TW202508213A - Simulation devices and mechanical control devices - Google Patents

Abstract

The simulation device simulates the change of the temperature of the motor including the blower. The simulation device has a temperature estimation unit and an action setting unit. The temperature estimation unit estimates the temperature of the stator based on the model of the motor, and the action setting unit sets the action of the blower. The model of the motor includes the models of the components of the motor, and coefficients related to heat transfer are set between the models of the components. The action setting unit sets the action of the blower based on the rate of change per unit time of the estimated temperature of the stator estimated by the temperature estimation unit.

Description

Simulation devices and mechanical control devices

The present disclosure relates to a simulation device and a mechanical control device.

It is known that a motor is arranged in a machine to move components. When the motor is driven, the stator core, the coil fixed to the stator core, etc. will heat up, and the temperature of the motor will rise. When the temperature of the motor is too high, the motor may not operate properly, the components of the motor may be damaged, or the life of the motor may be shortened. Therefore, it is known to arrange a blower in the motor to cool the body of the motor. It is known that the stator, etc. can be cooled by the flow of air generated by the blower.

The actual temperature of the components of the motor when the motor is driven can be detected by a temperature detector installed on the components of the motor. Alternatively, it can be estimated by a simulation that estimates the temperature of the motor. For example, a thermal model is known that estimates the temperature of the components of the motor based on the heat loss in the motor. Prior Art Literature Patent Literature

Patent document 1: Japanese Patent Publication No. 7-79592 Patent document 2: Japanese Patent Publication No. 11-37097 Patent document 3: Japanese Patent Publication No. 2018-121384

Invention Problems to be Solved

During the operation of the motor, the air is supplied to the motor by the blower, thereby effectively cooling the motor. However, if the blower is always driven at the maximum rotation speed, there is a problem that the power consumption of the motor increases.

Furthermore, when the blower is driven continuously at a fixed rotational speed, the temperature of the motor body will change in accordance with the load factor of the motor. When the load factor of the motor is large, the temperature of the motor will become high, and when the load factor is small, the temperature of the motor will become low. The heat of the motor is transferred to the components of the machine in contact with the motor. When the temperature fluctuation range of the motor becomes larger, the temperature fluctuation range of the components of the machine in contact with the motor will also become larger. As a result, thermal displacement will occur due to thermal expansion or contraction of the components of the machine.

When the components of a machine produce thermal displacement, the accuracy of the driving machine may deteriorate. For example, when the machine is a machine tool that cuts a workpiece, the heat of the motor may be transferred to the tool holding component that holds the tool. When the tool holding component expands thermally, the position of the front end of the tool changes, and the machining accuracy of the workpiece decreases. In this case, it is ideal for the temperature of the motor to vary as little as possible. In other words, it is ideal to be able to drive the motor at a fixed temperature as much as possible. Means used to solve the problem

One aspect of the present disclosure is a simulation device for simulating the change in temperature of a motor including a blower. The simulation device comprises: a memory unit for storing a model of the motor, wherein the model of the motor is a model for estimating the temperature of the components of the motor; a temperature estimating unit for estimating the temperature of the stator based on the model of the motor; and an action setting unit for setting the action of the blower. The model of the motor includes a model of the components of the motor and a model of the outside air. A heat capacity is set in the model of at least one component. Coefficients related to heat transfer are set between the models of the components of the motor and between the models of the components of the motor and the model of the outside air. The operation setting unit sets the operation of the blower according to the rate of change per unit time of the estimated temperature of the stator estimated by the temperature estimating unit.

The form used to implement the invention

Referring to Fig. 1 to Fig. 18, a motor simulation device and a machine control device for controlling a machine equipped with a motor in an embodiment are described. The motor simulation device of this embodiment has the following functions: using a thermal model of the motor, the temperature of a predetermined component of the motor is estimated. The machine control device has the function of controlling the operation of the machine according to an operation program.

(Machine structure) Figure 1 is a block diagram of a simulation device of a machine and a motor in this embodiment. Any machine equipped with a motor 10 can be used as the machine 1. In this embodiment, a machine tool for cutting a workpiece is cited as an example to illustrate the machine 1. A spindle motor or a feed shaft motor can be exemplified as the motor 10. The spindle motor rotates the spindle holding the tool, and the feed shaft motor is used to move the worktable holding the workpiece or the spindle head including the spindle along a predetermined coordinate axis.

The machine 1 has an electric motor 10 for driving the components of the machine 1, and a machine control device 41 for controlling the machine 1. The machine control device 41 of this embodiment has an operation processing device (computer). The machine control device 41 includes a CPU (Central Processing Unit) as a processor. The machine control device 41 has a RAM (Random Access Memory) and a ROM (Read Only Memory) connected to the CPU via a bus.

The machine 1 of this embodiment is numerically controlled. The machine 1 is driven according to the instruction statements recorded in the pre-made action program 45. When the machine 1 is a machine tool, the processing formula is equivalent to the action program 45. The machine control device 41 includes: a memory unit 42, which stores the action program 45; and an action control unit 43, which generates an action instruction for the motor 10 according to the action program 45. The machine 1 includes a drive device 44, and the drive device 44 includes a circuit that supplies power to the motor 10 according to the action instruction generated by the action control unit 43. The motor 10 is driven by the power supplied by the drive device 44.

The memory unit 42 may be composed of a non-temporary memory medium that can store information. For example, the memory unit 42 may be composed of a memory medium such as a volatile memory, a non-volatile memory, a magnetic memory medium, or an optical memory medium. The action control unit 43 is equivalent to a processor driven according to the action program 45. The processor reads the action program 45 to implement the control determined by the action program 45, thereby functioning as the action control unit 43.

FIG2 is a cross-sectional view of the motor of the present embodiment. Referring to FIG1 and FIG2, the motor 10 is a synchronous motor having a rotor 11 with a magnet 18. The motor 10 has a rotor 11 and a stator 12. The stator 12 includes a stator core 20 formed of a magnetic material and a coil 16 fixed to the stator core 20. The stator core 20 is formed of, for example, a plurality of magnetic steel plates stacked in the axial direction of the shaft 13. The coil 16 includes, for example, a winding wound on the stator core 20 and a resin portion that fixes the winding.

The rotor 11 is fixed to a rod-shaped shaft 13. The rotor 11 includes a rotor core 17 fixed to the outer peripheral surface of the shaft 13 and formed of a magnetic material, and a plurality of magnets 18 fixed to the rotor core 17. The magnets 18 of this embodiment are permanent magnets.

The shaft 13 is connected to other components in order to transmit rotational force. The shaft 13 rotates around the rotation axis RA. The shaft 13 is supported by bearings 14 and 15 as bearings. In this embodiment, in the motor 10, the side where the shaft 13 is connected to other components is called the front side. In addition, the opposite side of the front side is called the rear side. In the example shown in Figure 2, the arrow 91 shows the front side of the motor 10.

The motor 10 includes a housing 21 at the front and a housing 22 at the rear. The stator core 20 of the stator 12 is supported by the housings 21 and 22. The housing 21 supports the bearing 14. A bearing support member 24 supporting the bearing 15 is fixed to the housing 22. The housings 21 and 22 support the shaft 13 rotatably through the bearings 14 and 15. A rear cover 23 that closes the internal space of the housing 22 is fixed to the end of the rear side of the housing 22.

At the rear end of the shaft 13, a rotational position detector 32 for detecting the rotational position or rotational speed of the shaft 13 is arranged. The rotational position detector 32 of this embodiment is composed of an encoder. A temperature detector 31 for detecting the temperature of the coil 16 is fixed to the coil 16 of the stator 12. The temperature detector 31 of this embodiment is composed of a thermistor. The outputs of the temperature detector 31 and the rotational position detector 32 are input to the mechanical control device 41.

As the components of the motor 10, there can be exemplified the rotor 11, the rotor core 17, the magnet 18, the stator 12, the stator core 20, the coil 16, the housing 21, 22, the shaft 13, the back cover 23, the bearing support member 24, the bearings 14, 15, the temperature detector 31, and the rotation position detector 32. The components of the motor 10 are not limited to this form, and any part constituting the motor 10 can be adopted. For example, a frame covering the outer peripheral surface of the stator core can be arranged as a component of the motor.

The motor 10 of this embodiment includes a blower 29 that supplies air for cooling the motor body. The blower 29 of this embodiment is fixed to the stator core 20 through a cylindrical member 25. The cylindrical member 25 is fixed to the stator core 20. The space inside the cylindrical member 25 constitutes a flow path for air.

The blower 29 includes a cooling fan 27, a housing 28, and a motor for rotating the cooling fan 27. The blower 29 of this embodiment is arranged so that the rotation axis of the cooling fan 27 coincides with the rotation axis RA of the shaft 13. The cooling fan 27 is not limited to this form, and can be arranged at any position so that air contacts the main body of the motor.

The stator core 20 of this embodiment has a through hole 26a for circulating cooling air. The through hole 26a is penetrated from one end face of the stator core 20 to the other end face along the axial direction of the rotor 11. The housing 21 has a through hole 26b for circulating air. The through hole 26b is connected to the through hole 26a. In addition, an air hole 28a for circulating air is formed on the housing 28 of the blower 29.

When the blower 29 is driven, the cooling fan 27 rotates, causing the air to flow in the direction indicated by the arrow 91. The cooling air flows into the interior of the housing 28 from the air hole 28a of the housing 28. The cooling air circulates in the interior of the housing 28 and in the interior of the cylindrical member 25. The cooling air circulates in the air flow path between the housing 22 and the cylindrical member 25. As indicated by the arrow 92, the cooling air circulates in the through hole 26a of the stator core 20 and the through hole 26b of the housing 21. The cooling air cools the housing 22 on the rear side, the stator core 20, and the housing 21 on the front side. The flow of cooling air is not limited to this form, and the cooling air may also flow in the opposite direction of arrow 91.

(Structure of simulation device) Simulation device 2 estimates the temperature of the components of the motor. In the present embodiment, the temperature of the stator among the components of the motor is estimated. As the temperature of the stator, the temperature of the stator core, the temperature of the coil wound around the stator core, and the temperature of the frame arranged around the stator core can be considered. In the present embodiment, the temperature of the stator core 20 is estimated as the temperature of the stator. Simulation device 2 estimates the change of the temperature of the stator core 20 with respect to the passage of time. In the present embodiment, the temperature actually measured by the temperature detector 31 is referred to as the measured temperature. In addition, the temperature of the component estimated by the simulation device 2 is referred to as the estimated temperature.

The simulation device 2 includes a calculation processing device (computer) including a CPU as a processor. The simulation device 2 is formed to be able to communicate with the machine control device 41. The simulation device 2 includes a memory unit 51 for storing information related to the simulation of the motor.

The memory unit 51 may be composed of a non-temporary memory medium capable of storing information. For example, the memory unit 51 may be composed of a memory medium such as a volatile memory, a non-volatile memory, a magnetic memory medium, or an optical memory medium. The program for driving the simulation device 2 is stored in the memory unit 51. In particular, the program for the simulation execution unit 64 and the program for the parameter setting unit 57 are stored in the memory unit 51.

The simulation device 2 includes a display unit 52 for displaying information related to the simulation of the motor. The display unit 52 can be formed of any display panel such as a liquid crystal display panel or an organic EL (Electro Luminescence) display panel.

The simulation device 2 in this embodiment includes a parameter setting unit 57 for setting parameters included in the model of the motor. The parameter setting unit 57 includes a temperature estimation unit 53 for calculating the temperature of the components of the motor. The temperature estimation unit 53 includes a loss calculation unit 54, which calculates the amount of heat generated by the primary copper loss of the coil 16 and the amount of heat generated by the iron loss of the stator core 20 based on the operation instruction of the motor 10. The temperature estimation unit 53 includes a temperature calculation unit 55, which estimates the temperature of the components of the motor using the model (thermal model) of the motor. The temperature calculation unit 55 calculates the estimated temperature of the component based on the heat generated by the primary copper loss and iron loss, the heat capacity of the model of each component, and the coefficient related to the heat transfer between the models of the component.

The parameter setting unit 57 includes a parameter calculating unit 59 that calculates parameters included in the model of the motor 10. The parameters include the heat capacity set in the model of the component of the motor 10 and a coefficient related to heat transfer between the models of the component.

The parameter setting unit 57 includes a state acquisition unit 58, which acquires the driving state of the motor 10 when the motor 10 is actually driven. The driving state of the motor 10 includes a measured temperature, which is a measured temperature detected by a temperature detector 31 installed on the motor 10. The driving state of the motor 10 includes: an action command of the motor 10 output from the action control unit 43, and a rotation speed output from the rotation position detector 32. In addition, the state acquisition unit 58 can acquire the temperature of the outside air from the outside air temperature detector 33. The outside air temperature detector 33 is configured to detect the temperature around the machine 1, for example.

The parameter calculation unit 59 of this embodiment calculates the parameters so that the change of the estimated temperature of the temperature detector calculated by the motor model corresponds to the change of the actual measured temperature. The parameter calculation unit 59 of this embodiment can set the parameters of the motor model by machine learning.

The loss calculation unit 54 of the temperature estimation unit 53 calculates the amount of heat generated by the coil 16 and the stator core 20 based on the action command generated by the action control unit 43 and the rotation speed detected by the rotation position detector 32. In addition, the temperature calculation unit 55 calculates the estimated temperature of the temperature detector 31 based on the amount of heat generated by the coil 16 and the stator core 20 and the thermal model.

The parameter calculation unit 59 includes an evaluation unit 60 that compares the estimated temperature of the temperature detector 31 with the measured temperature of the temperature detector 31 obtained by the state acquisition unit 58 to evaluate the estimated temperature of the temperature detector. The parameter calculation unit 59 includes a parameter change unit 61 that changes the value of the parameter according to the evaluation result of the evaluation unit 60.

Each of the parameter setting unit 57, the temperature estimation unit 53, the loss calculation unit 54, and the temperature calculation unit 55 is equivalent to a processor driven by a program. Each of the state acquisition unit 58, the parameter calculation unit 59, the evaluation unit 60, and the parameter change unit 61 is equivalent to a processor driven by a program. The processor functions as each unit by executing the control determined by the program.

The simulation device 2 includes a simulation execution unit 64, and the simulation execution unit 64 simulates the change of the temperature of the components of the motor. The simulation execution unit 64 is formed to calculate the change of the temperature of the components of the motor in a time series manner. The simulation execution unit 64 includes the temperature estimation unit 53. The temperature estimation unit 53 calculates the temperature of the components of the motor according to the model of the motor, and the model of the motor includes the parameters set by the parameter setting unit 57.

The simulation execution unit 64 includes an action setting unit 65 for setting the action of the blower 29 of the motor 10. The simulation execution unit 64 includes an auxiliary program generating unit 66 for generating an auxiliary program, wherein the auxiliary program determines the action of the blower 29 relative to the action instruction based on the action program 45. The simulation execution unit 64 includes a variation range comparison unit 67, wherein the variation range of the temperature of the stator in a predetermined period is calculated. The simulation execution unit 64 includes a power consumption comparison unit 68, wherein the power consumption comparison unit 68 is used to calculate the power consumption of the blower in a predetermined period.

The simulation execution unit 64 is equivalent to a processor driven according to a predetermined program. In addition, each unit of the action setting unit 65, the auxiliary program generation unit 66, the variation range comparison unit 67, and the power consumption comparison unit 68 is equivalent to a processor driven according to a predetermined program. The processor reads the program and implements the control determined by the program, thereby performing the function as each unit.

A flow chart for setting the control of the operation of the blower of the motor in the simulation device of the present embodiment is shown in Fig. 3. In step 101, the parameter setting unit 57 sets the parameters included in the model of the motor according to the temperature measured by the temperature detector 31.

(Model of the motor and parameter setting of the model of the motor) Fig. 4 shows the model of the motor that models the heat transfer of the synchronous motor in the present embodiment. The model of the motor in the present embodiment is a thermal model. The model of the motor includes models of a plurality of components. The model of the motor includes the following parameters: the heat capacity of the components, and coefficients related to heat transfer between the components. The model 10a of the motor includes models of the main components that constitute the motor 10. The model 10a of the motor includes: a model 11a of the rotor, a model 20a of the stator core, and a model 16a of the coil wound on the stator core.

Furthermore, the model 10a of the motor includes a model 31a of a temperature detector for detecting the temperature of the coil 16. In this embodiment, the model 31a of the temperature detector having a small heat capacity is set, but the present invention is not limited to this form. The heat capacity of the temperature detector 31a may be set to zero, and the temperature of the temperature detector may be calculated as being the same as the temperature of the model of the component on which the temperature detector is mounted.

Referring to Fig. 2, an air layer exists between the rotor 11 and the stator core 20. In addition, an air layer exists between the rotor 11 and the coil 16. Referring to Fig. 4, the motor model 10a in this embodiment includes a model 35a of the air layer. Furthermore, the motor model 10a includes a model 36a of the external air as a model of the air around the motor 10.

A plurality of parameters including heat capacity and coefficients related to heat transfer are set in the model 10a of the motor. Heat capacity is set in the model of at least one component. Temperatures T1, T2, T3, T4, T5 as variables and heat capacities _C1 , _C2 , _C3 , _C4 , _C5 as constants are set in each of the models of the coil 16a, the stator core 20a, the air layer 35a, the _{rotor 11a} , _and the temperature detector _31a . In addition, temperature _Tr is set as a variable in _the model 36a of the outside air.

The heat of one component of the motor 10 is transferred to other components. A coefficient related to heat transfer is set between the models of the components of the motor 10. As the coefficient related to heat transfer, a heat transfer coefficient or a coefficient obtained by multiplying the heat transfer coefficient by the contact area between the components can be used. In this example, a coefficient obtained by multiplying the heat transfer coefficient by the contact area is determined.

A coefficient ha related to heat transfer is set between the model 20a of the stator core and the model 16a of the coil. A coefficient hc1 related to heat transfer is set between the model 35a of the air layer and the model 16a of the coil. A coefficient hc2 related to heat transfer is set between the model 35a of the air layer and the model 20a of the stator core. A coefficient hc3 related to heat transfer is set between the model 35a of the air layer and the model 11a of the rotor. A coefficient hd related to heat transfer is set between the model 16a of the coil and the model 31a of the temperature detector. Furthermore, in order to simulate the release of heat from the stator core 20 to the outside air, a coefficient hb related to heat transfer is set between the stator core model 20a and the outside air model 36a.

In the model 10a of the motor in this embodiment, the primary copper loss P _c1 generated in the coil 16 of the stator 12 can be considered as the heat generated by the components. The amount of heat generated due to the primary copper loss is input to the model 16a of the coil. In addition, the iron loss P _i of the stator core 20 generated by the magnetic force of the magnet 18 of the rotor 11 can be considered. The amount of heat generated due to the iron loss is input to the model 20a of the stator core.

Heat moves between components such as the coil and the stator core depending on the size of the coefficient related to heat transfer. In addition, the temperature of each component rises or falls according to the difference between the heat input and the heat output. The temperature change rate of each component of the motor model 10a shown in Figure 3 can be expressed by the following equations (1) to (5). In each component, the temperature change rate can be calculated by dividing the difference between the heat input and the heat output by the heat capacity.

[Mathematical formula 1]

The heat capacities _C1 , _C2 , _C3 , _C4 , and _C5 of the components are constants and can be determined in advance. The coefficients ha, hb, hc1, hc2, hc3, and hd related to heat transfer are coefficients obtained by multiplying the heat transfer coefficient by the contact area. The coefficients ha, hb, hc1, hc2, hc3, and hd are constants and can be determined in advance. The loss calculation unit 54 of the temperature estimation unit 53 calculates the primary copper loss _Pc1 in the coil 16 and the iron loss _P1 in the stator core as described later. The temperature calculation unit 55 of the temperature estimation unit 53 can calculate the temperature change in the small time dt according to the above-mentioned equations (1) to (5).

Next, the calculation method of the primary copper loss P _c1 and the iron loss P _i included in equations (1) and (2) is explained. The rotation speed of the motor 10 and the load factor (ratio relative to the maximum load) of the motor 10 can be set in advance by the operator according to the operation performed by the machine. The loss calculation unit 54 of the temperature estimation unit 53 calculates the primary copper loss P _c1 and the iron loss P _i . The loss diagram used to calculate the loss is shown in Table 1.

[Table 1]

Table 1 shows the loss at maximum output, the loss at no load, and the current at maximum output relative to the rotation speed (rotation speed) of the motor 10. The loss P _m at maximum output is the loss when the load factor of the motor is 100%, and is a value determined by the rotation speed of the motor. The loss P _n at no load is the loss when the load factor of the motor is zero, and is dependent on the rotation speed of the motor. The current _Im at maximum output is the current value when the load factor is 100% at each rotation speed. The loss diagram shown in Table 1 can be produced by actually driving the motor. This loss diagram can be stored in advance in the memory unit 51 of the simulation device 2, for example.

The loss calculation unit 54 calculates the total loss _Pt including the primary copper loss _Pc1 and the iron loss _Pi . The total loss _Pt can be calculated by the following equations (6) and (7).

[Mathematical formula 2]

The total loss _Pt can be calculated from the loss _Pm at maximum output, the loss _Pn at no load, and the motor load factor LF. Since the motor rotation speed and load factor are already determined, the loss _Pm at maximum output and the loss _Pn at no load can be calculated from Table 1. The constants k1 and k2 can be determined in advance by the operator. Next, the primary copper loss _Pc1 can be calculated by the following equations (8) and (9).

[Mathematical formula 3]

The primary copper loss P _c1 is equivalent to the Joule heat of the current flowing in the coil 16. In addition, the current I flowing in the coil 16 can be calculated by multiplying the current _Im at the maximum output by the load factor LF of the motor. The current _Im at the maximum output can be obtained from Table 1. Here, the primary resistance r1 of the coil 16 is measured in advance. Next, the iron loss _Pi can be calculated by the following formula (10). The iron loss _Pi can be calculated by subtracting the primary copper loss P _c1 from the total loss P _t .

[Mathematical formula 4]

The temperature estimation unit 53 obtains the motor operation mode from the state acquisition unit 58. The operation mode includes the rotation speed and the load factor for driving the machine 1. The temperature calculation unit 55 of the temperature estimation unit 53 can first set the temperature T ₁ to T ₅ of each component to an arbitrary temperature. For example, the temperature calculation unit 55 sets the temperature T ₁ to T ₅ of the component to the normal temperature _Tr of the outside air. The temperature _Tr of the outside air can be determined in advance according to the location where the machine 1 is arranged.

The loss calculation unit 54 of the temperature estimation unit 53 calculates the primary copper loss and iron loss based on the rotation speed and the load factor of the motor in the operation mode. Then, the temperature calculation unit 55 can calculate the change in the temperature _T5 of the temperature detector 31 in the micro time dt by solving the above equations (1) to (5). In this way, the operator can determine the operation mode of the motor and estimate the change in the temperature of the temperature detector over time when the motor is operated in the operation mode.

Incidentally, the motor model 10a of the present embodiment is configured to estimate the temperature of one of the plurality of components of the motor with high accuracy. In this example, the model 10a is configured to estimate the temperature T ₅ of the temperature detector model 31a with high accuracy.

In addition, the heat capacities _C1 to _C5 set in the motor model 10a, and the coefficients ha, hb, hc1, hc2, hc3, and hd set between the components and related to heat transfer have inherent values depending on the materials, shapes, and arrangements of the components. However, in the motor model 10a in the present embodiment, at least some of the parameters among the plurality of heat capacities and the plurality of coefficients related to heat transfer may be set to values different from the actual heat capacities or the coefficients related to actual heat transfer.

Each parameter is set so that the change of the temperature _T5 of the model 31a of the temperature detector corresponds to the change of the actual temperature. For example, the parameters of the model of the motor can be set so that the temperature of the temperature detector shows a value close to the actual temperature. In addition, the heat capacity and the coefficients related to heat transfer are calculated, and as a result, all the heat capacities and all the coefficients related to heat transfer of the components correspond to the actual heat capacity and the actual coefficients related to heat transfer with good accuracy. Furthermore, when the temperature estimation unit estimates the temperature of the components, the temperatures of all the components can also correspond to the actual temperatures of the components with good accuracy.

Referring to FIG. 1 , the parameter calculation unit 59 calculates the heat capacity included in the motor model 10a, the coefficient related to heat transfer, and the constants k1 and k2 of equations (6) and (7). First, the operator actually drives the motor 10 according to the predetermined operation mode. The state acquisition unit 58 acquires the load factor of the motor 10, the rotation speed of the motor 10, and the temperature output from the temperature detector 31 as the driving state of the motor 10. In addition, the state acquisition unit 58 acquires the temperature of the outside air from the outside air temperature detector 33.

FIG5 is a diagram showing an operation mode when the motor is driven in order to set the parameters included in the model of the motor of the present embodiment. FIG5 shows an operation mode when there is no load. In this operation mode, no load is applied to the motor 10, and the rotation speed of the motor 10 is gradually increased. The load factor of the motor is temporarily increased at predetermined time intervals, thereby increasing the rotation speed of the motor 10.

The temperature detected by the temperature detector 31 gradually increases. During the time t1 to t7, the load factor of the motor 10 is temporarily increased, thereby increasing the rotation speed of the motor 10. The state acquisition unit 58 acquires the load factor of the motor 10, the rotation speed of the motor 10, and the temperature output from the temperature detector 31 at predetermined intervals, and stores them in the memory unit 51. In addition, in the present embodiment, although the state acquisition unit 58 acquires the temperature of the outside air from the outside air temperature detector 33 at predetermined intervals, it is not limited to this form. The temperature of the outside air may also be a fixed temperature.

1 , the state acquisition unit 58 acquires a torque command, which is an operation command generated by the operation control unit 43 included in the machine control device 41. Since the torque command corresponds to the load factor of the motor 10, the state acquisition unit 58 can calculate the load factor from the torque command.

The parameter calculation unit 59 calculates the parameters of the motor model 10a based on the variables acquired by the state acquisition unit 58. The parameter calculation unit 59 of this embodiment calculates parameters including heat capacity C1, _C2 , _C3 , _C4 , _C5 and coefficients ha, hb, hc1, hc2, hc3, hd related to heat transfer based on the heat generated in the coil ₁₆ and the stator core 20 and the temperature detected by the temperature detector 31. The parameter calculation unit 59 calculates constants k1 and k2 in equations (6) and (7) as parameters. In this example, the parameter calculation unit 59 calculates the parameters so that the change in the estimated temperature of the temperature detector model 31a during the simulation approaches the actual measured temperature change.

The parameter calculation unit 59 sets the initial value of each parameter. The initial value of the parameter can be set by any method. The loss calculation unit 54 calculates the heat generated by the primary copper loss of the coil 16 and the heat generated by the iron loss of the stator core 20. The loss calculation unit 54 calculates the primary copper loss P c1 and the iron loss P i based on the rotation speed of the motor 10 and the load factor of the motor 10 obtained by the state acquisition unit 58, and uses Table ₁ and equations (6) to ( ₁₀ ).

The constants k1 and k2 are included in the equations (6) and (7) for calculating the primary copper loss P _c1 and the iron loss P _i . In addition, the loss calculation unit 54 calculates the loss in the predetermined micro time dt, that is, calculates the amount of heat generated in the micro time. In this way, the loss calculation unit 54 calculates the primary copper loss P _c1 and the iron loss P _i in the equations (1) and (2) based on the motor operation command (load factor) and the actual measurement value including the output of the rotation position detector 32.

The temperature calculation unit 55 estimates the temperature of the components. The temperature calculation unit 55 can calculate the change in the estimated temperature detected by the temperature detector 31 over time after the start of the drive of the motor 10 using the various parameters and the loss calculated by the loss calculation unit 54, based on the model 10a of the motor and based on the temporarily determined parameters. The temperature of the model of each component of the motor 10 can be calculated using the differential equations of the above-mentioned equations (1) to (5). The initial value of the temperature of the model of each component can be set to, for example, the temperature of the outside air when the drive of the motor 10 is started, that is, to room temperature.

The evaluation unit 60 of the parameter calculation unit 59 compares the temperature (estimated temperature) of the temperature detector model 31a calculated by the temperature calculation unit 55 with the measured temperature actually measured by the temperature detector 31, thereby evaluating the parameters temporarily set in the motor model 10a. In this example, the evaluation unit 60 does not evaluate variables other than the temperature of the temperature detector model 31a, but only evaluates the temperature of the temperature detector model 31a.

Next, the parameter changing section 61 of the parameter calculating section 59 changes the parameters according to the evaluation result of the evaluating section 60. Then, according to the changed parameters, the calculation of the loss by the loss calculating section 54, the calculation of the estimated temperature of the model of the temperature detector by the temperature calculating section 55, the evaluation by the evaluating section 60, and the parameter changing by the parameter changing section 61 are repeated by the same calculation as above. When the evaluation by the evaluating section satisfies the conditions determined in advance, the parameters can be determined as the final parameters.

Here, the number of combinations of the plurality of parameters in the model 10a of the motor is very large. The plurality of parameters can be determined by a machine learning method. For example, the plurality of parameters can be set by a Bayesian optimization method. In Bayesian optimization, a target function that is an evaluation object is generated for an explanatory variable including a parameter that is an input. Then, a parameter that is predicted to be the minimum or maximum of the target function is searched and set. By repeating this parameter search, the optimal value of the parameter can be set. Here, the range for setting each parameter can be determined in advance.

In this example, regarding the temperature of the temperature detector 31, the difference between the temperature of the model 31a of the temperature detector estimated by the model 10a of the motor (estimated temperature) and the measured temperature actually detected by the temperature detector 31 is set as the target function. That is, regarding the temperature of the temperature detector 31, the target function can use the difference between the predicted value calculated from equations (1) to (5) based on the temporarily set parameters and the measured value actually detected by the temperature detector 31. For example, the average value of the difference within a small time period can be used as the target function. Then, the parameter changing unit 61 searches for the next parameter in such a way that the target function becomes smaller.

In Bayesian optimization, parameter search and parameter evaluation can be repeated. If the target function is within a predetermined judgment range, the evaluation unit 60 can adopt the value of the parameter at that time. On the other hand, when the target function exceeds the predetermined judgment range, the next parameter search can be performed. In the Bayesian optimization method, since the search is performed while predicting the area where the solution exists, the amount of calculation processing can be suppressed. The memory unit 51 can store the generated motor model 10a in advance.

The parameters included in the model 10a of the motor can be set by any method other than the setting of the parameters of the Bayesian optimization. For example, the range of each parameter setting can be determined in advance. The parameter changing unit 61 of the parameter calculation unit 59 randomly sets a plurality of parameters within the parameter range. The temperature calculation unit 55 estimates the temperature of the model 31a of the temperature detector based on the set parameters. The evaluation unit 60 can evaluate the set parameters based on the measured value of the temperature obtained from the temperature detector 31. Such a parameter setting method is called a random search method.

Alternatively, the parameter changing unit 61 may set the parameters at predetermined intervals within the range of the set parameters. The temperature calculating unit 55 estimates the temperature of the model 31a of the temperature detector using the set parameters. The evaluating unit 60 evaluates all combinations of discretely set parameters. This method is called a grid search method.

In the random search method or the grid search method, the evaluation unit 60 may also set the temperature of the temperature detector 31 as the object of evaluation, similarly to the Bayesian optimization method. If the target function is within the predetermined judgment range, the evaluation unit 60 may adopt the value of the parameter at that time. Alternatively, the evaluation unit 60 may adopt the parameter with the best target function. The evaluation unit 60 may determine the parameter in the model 10a of the motor as the parameter for which the estimated temperature of the temperature detector 31 and the actual measured temperature detected by the temperature detector 31 are well consistent.

In the above-mentioned embodiment, although the operation under no load is shown as the operation mode for driving the motor 10 in order to set the parameters of the model 10a of the motor, it is not limited to this form. When determining the parameters of the model of the motor, it is ideal to operate the motor 10 in various operation modes and obtain the driving state of the motor 10. For example, an operation mode can be adopted in which the load factor of the motor 10 is repeatedly increased and decreased. The load factor of the motor 10 can be greatly changed to change the rotation speed of the motor. The temperature detected by the temperature detector 31 will rise or fall rapidly. In this way, an operation mode including a rapid temperature change of the motor can be adopted.

In addition, the parameter setting unit 57 of this embodiment sets the parameters of the motor model 10a according to the operation of the blower 29 of the motor 10. That is, the parameter setting unit 57 creates a plurality of motor models 10a according to the operation of the blower 29 of the motor 10.

In this embodiment, a first model of the motor 10 can be produced when the blower 29 is driven at a fixed rotational speed. Here, a first model of the motor 10 is produced when the blower 29 is driven at the maximum rotational speed. The state acquisition unit 58 of the parameter setting unit 57 acquires the driving state of the motor when the blower 29 is driven at a fixed rotational speed. The parameter calculation unit 59 calculates the parameters of the model of the motor when the blower 29 is driven at a fixed rotational speed.

Furthermore, a second model of the motor 10 can be prepared when the blower 29 of the motor 10 is stopped. The state acquisition unit 58 of the parameter setting unit 57 acquires the driving state of the motor when the blower 29 is stopped. The parameter calculation unit 59 calculates the parameters of the model of the motor when the blower 29 is stopped. In this way, a thermal model can be generated in response to the operation of the blower 29, and the aforementioned thermal model is a thermal model in which all parameters such as heat capacity included in the model of the motor have been changed.

Alternatively, referring to FIG. 4 , the amount of heat released from the model 20a of the stator core to the model 36a of the outside air by alternately driving and stopping the blower 29 of the motor 10 will change. That is, the coefficient hb related to heat transfer will change. Therefore, in the calculation of the parameters in the model of the motor with the blower stopped, only the coefficient hb related to heat transfer can be calculated. Parameters other than the coefficient hb related to heat transfer can be the parameters calculated when the blower is driven at a fixed rotational speed. The coefficient hb related to heat transfer when the blower is stopped can be calculated by any method such as the aforementioned Bayesian optimization method, random search method, and grid search method.

In the above embodiment, although the synchronous motor whose rotor has permanent magnets is described, it is not limited to this embodiment. The temperature of any component of the motor can be estimated by using the thermal model. For example, the motor model of this embodiment can also be applied to an induction motor whose rotor does not have permanent magnets.

FIG6 shows a model of another motor in the present embodiment. The model 30a of another motor is a model of an induction motor. The rotor of the induction motor includes a cage-shaped conductor formed of stainless steel, copper, etc. The cage-shaped conductor is fixed to the shaft and rotates integrally with the shaft. In the induction motor, the induced current flows inside the cage-shaped conductor due to the magnetic force generated by the coil of the stator. A magnetic field is generated around the cage-shaped conductor, and the rotor rotates.

In the induction motor, since the current flows in the cage-shaped conductor of the rotor, secondary copper loss P _c2 is generated as secondary loss. Secondary loss is equivalent to Joule heat caused by the current flowing in the cage-shaped conductor. In the model 30a of the other motor, heat is generated due to the secondary copper loss of the rotor. The heat capacity in the components of the other motor and the coefficient related to heat transfer between the components are the same as the model 10a of the motor for the synchronous motor mentioned above.

The differential equation for calculating the temperature change of the rotor in the other motor model 30a is different from the motor model 10a for the synchronous motor of the present embodiment. The differential equation expressing the temperature change of the rotor is the following equation (11).

[Mathematical formula 5]

In equation (11), the heat generated by the secondary copper loss P _c2 is added to equation (4) of the model 11a of the motor rotor of this embodiment. The other differential equations representing the temperature changes of the coil, stator core, air layer, and temperature sensor are the same as the differential equations in the thermal model of the synchronous motor.

The loss calculation unit 54 calculates the amount of heat generated by the secondary copper loss generated in the conductor of the rotor. The loss calculation unit 54 estimates the current flowing in the cage-shaped conductor. The loss calculation unit 54 can calculate the secondary copper loss by the current flowing in the conductor, the secondary resistance of the conductor, the inductance of the conductor, and the mutual inductance between the conductor, the stator, and the coil. The inductance, mutual inductance, and secondary resistance of the conductor can be determined in advance.

The total loss _Pt and primary copper loss _Pc1 in the induction motor can be calculated in the same way as the total loss and primary copper loss in the synchronous motor. Then, the iron loss _Pi can be calculated by taking the secondary copper loss _Pc2 into consideration using the following formula (12).

[Mathematical formula 6]

In this way, the primary copper loss, iron loss, and secondary copper loss are calculated in the model 30a of the other motor. In the model 30a of the other motor, the parameter calculation unit 59 can also calculate the parameters included in the model 30a of the other motor by the same control as the model 10a of the motor for the synchronous motor.

FIG7 shows a graph of the estimated temperature of the temperature detector estimated by the temperature estimation unit using the parameters calculated by the parameter calculation unit of the present embodiment. Here, an example of an induction motor as another motor is shown. FIG7 shows a graph when a simulation is performed using parameter group A and parameter group B having different values. Parameter group A and parameter group B are calculated by parameter calculation unit 59. The parameters included in parameter group A and parameter group B are shown in Table 2.

[Table 2]

Parameter group A and parameter group B can be obtained by driving other motors with different operation modes. Table 2 shows the coefficients related to heat transfer obtained by multiplying the heat transfer coefficient between the components of the motor by the contact area. In addition, the heat capacity is calculated by multiplying the specific heat of the material of each component by the mass. Since the specific heat of each material can be determined in advance, the mass m of the component used to calculate the heat capacity is shown in Table 2. By comparing parameter group A and parameter group B, it can be seen that the values of some parameters such as the coefficients hc2 and hd related to heat transfer and the mass _m4 of the rotor will be different between the two parameter groups A and B.

On the other hand, referring to FIG. 7 , it can be seen that the estimated temperature of the temperature detector calculated using the parameter group B is well consistent with the estimated temperature of the temperature detector calculated using the parameter group A. In particular, the temperature changes are well consistent both during the period of temperature rise and during the period of temperature fluctuation within a predetermined range. In addition, it can be seen that the temperature change shown in FIG. 6 estimated by the temperature estimation unit 53 is well consistent with the temperature change detected by the temperature detector 31 when the motor 10 is actually driven.

In the above-mentioned embodiment, although an example of installing a temperature detector on a coil including a winding is cited for explanation, it is not limited to this form. The temperature detector can be installed on any component of the motor. For example, a temperature detector can also be installed on a stator core. In addition, a plurality of temperature detectors can be installed on a plurality of components of the motor. The evaluation unit of the parameter calculation unit can compare the measured temperatures of a plurality of temperature detectors with the estimated temperatures calculated by the simulation. The parameter changing unit can set the parameters of the model of the motor in such a way that the estimated temperatures of a plurality of components are close to the actual measured temperatures detected by the temperature detector.

The more temperature detectors are installed on the motor, the closer the values of the multiple parameters of the motor model can be to the actual values. In addition, the estimated temperature of each component of the motor can be made close to the actual measured temperature. When multiple temperature detectors are installed, it is possible that all heat capacities and all coefficients related to heat transfer are the same as the actual heat capacities and the actual coefficients related to heat transfer. In this case, when the temperature estimation unit estimates the temperature of the component, the temperature of all components will correspond to the actual temperature of the component with good accuracy.

(Estimation of the driving state of the motor by the motion estimation device) Referring to FIG. 1, in order to perform simulation by the simulation execution unit 64 of the simulation device 2 of this embodiment, the heat generation must be calculated by the loss calculation unit 54 of the temperature estimation unit 53. In order to calculate the heat generation by the loss calculation unit 54, as described above, information 69 of the driving state of the motor including the load factor and rotation speed of the motor is required.

Referring to Figures 8 to 15, the motion estimation device for estimating the driving state of the motor in this embodiment is explained. The driving state of the motor includes the load factor and the rotation speed of the motor. The machine tool 1 as the machine of this embodiment processes the workpiece while changing the relative position of the tool with respect to the workpiece. The machine tool of this embodiment is equipped with: a spindle motor for rotating the tool; and a moving device for moving at least one of a worktable holding the workpiece and a spindle head holding the tool. The moving device includes a feed shaft motor configured corresponding to each feed shaft.

The feed axis of this embodiment is composed of three mutually orthogonal linear motion axes (X axis, Y axis, and Z axis). In the machine tool of this embodiment, the worktable that fixes the workpiece moves in the direction of the X axis and the direction of the Y axis, and the spindle that holds the tool moves in the direction of the Z axis. The feed axis of the machine tool is not limited to this form, and can be composed of any linear motion axis or rotary feed axis.

FIG8 shows a block diagram of the action estimation device in the present embodiment. The action estimation device 81 estimates the driving state of the motor installed in the machine tool. The action estimation device 81 includes an operation processing device (computer) having a CPU as a processor. The action estimation device 81 includes a memory unit 82, and the memory unit 82 stores information used to estimate the driving state of the motor. The memory unit 82 can be composed of a non-transitory storage medium that can store information. The memory unit 82 can be composed of a storage medium that can store information, such as a volatile memory, a non-volatile memory, a magnetic storage medium, or an optical storage medium.

The motion estimation device 81 inputs an estimation program 71, which is a program for estimating the driving state of the motor. The estimation program 71 is prepared in advance by the operator who performs the simulation. In addition, the moving device includes a speed reducer connected to the motor and a driving mechanism for driving components such as a workbench. The driving mechanism includes, for example, a ball screw mechanism for moving the workbench of a machine tool. The motion estimation device 81 inputs information 72 of the moving device. The moving device information 72 includes information such as the gear ratio of the speed reducer and the pitch of the ball screw.

Furthermore, inertia information 73 is input to the action estimation device 81. The inertia (inertia torque) related to the drive of the motor includes the inertia of the component driven by the motor. Furthermore, the inertia related to the drive of the motor includes the inertia of the load applied to the motor. For example, the inertia includes: the inertia of the rotor of the motor, the inertia of the speed reducer connected to the feed shaft motor, and the inertia of the main shaft connected to the main shaft motor. The inertia can be calculated in advance by the operator performing the simulation. Furthermore, the output characteristic 74 of the motor is input to the action estimation device 81. The estimation program 71 , the information 72 of the moving device, the information 73 of the inertia, and the output characteristics 74 of the motor are stored in the memory unit 82 .

The motion estimation device 81 includes a calculation unit 83, which calculates variables indicating the driving state of the motor according to the estimation program 71. The variables indicating the driving state of the motor include the rotation speed of the motor, the angular acceleration of the motor, the load factor of the motor, and the rotation position of the motor. The calculation unit 83 includes a speed estimation unit 84, which calculates the change of the rotation speed of the motor over time. The calculation unit 83 includes a torque estimation unit 85, which estimates the change of the load factor of the motor over time.

The calculation unit 83 includes a determination unit 86 that determines a variable estimated by the calculation unit 83. The calculation unit 83 includes a display control unit 87 that generates a command to display the result determined by the determination unit 86 on the display unit 88.

The calculation unit 83 is equivalent to a processor of the operation processing device driven according to a predetermined rule. The calculation unit 83 of this embodiment is equivalent to a processor driven according to the estimation program 71. In particular, each unit of the speed estimation unit 84, the torque estimation unit 85, the determination unit 86, and the display control unit 87 is equivalent to a processor of the operation processing device. The processor is driven according to the estimation program 71, thereby performing functions as each unit.

The operation estimation device 81 includes a display unit 88 for displaying information related to the estimation of the driving state of the motor. The display unit 88 is composed of a display panel such as a liquid crystal display panel. The display unit 88 displays arbitrary information according to the instruction from the display control unit 87.

In addition, although the motion estimation device of this embodiment is composed of a different operation processing device from the operation processing device of the mechanical control device and the operation processing device of the simulation device, it is not limited to this form. The operation processing device of the mechanical control device or the operation processing device of the simulation device may also have the function of the motion estimation device. For example, the processor of the mechanical control device may also have the function of the calculation unit of the motion estimation device.

The motion estimation device 81 of this embodiment estimates the variable indicating the driving state of the motor according to the estimation program 71. The aforementioned estimation program 71 is a modification of a machining program as an motion program for driving a machine tool. In the estimation program 71 of this embodiment, auxiliary variables useful for estimating the driving state of the motor are added to the instruction statement of the machining program.

The calculation unit 83 of the motion estimation device 81 of the present embodiment predicts the change of the driving state of the motor in a time series manner based on the instruction statement including the auxiliary variables recorded in the estimation program 71, the output characteristics of the motor, and the inertia related to the driving of the motor. The inertia related to the driving of the motor includes the inertia of the rotor, etc. and the inertia of the load of the motor. In particular, the calculation unit 83 calculates at least one of the change of the rotation speed of the motor over time and the change of the load rate of the motor over time. That is, the calculation unit 83 calculates at least one of the rotation speed of the motor and the load rate of the motor in a time series manner. Furthermore, the operation estimating device 81 estimates the time length for which the machine tool performs an operation.

In the estimation control of the spindle motor of the motion estimation device 81 of the present embodiment, the driving state of the spindle motor is estimated. The time constant for changing the rotation speed of the spindle is not specified for the spindle motor. The time constant is the length of time from one rotation speed to the target rotation speed. The time constant is a variable corresponding to the angular acceleration of the motor. In the control of the present embodiment, the driving state of the spindle motor is estimated according to the estimation program, and the aforementioned estimation program is an auxiliary variable that adds a load factor of the motor to the instruction statement of the machining program.

FIG9 shows an example of a machining formula corresponding to an estimation program in the estimation control of the spindle motor. In the machining formula of the machine tool, there are command statements for operating the spindle motor and the feed shaft motor. The machining formula is composed of command statements called codes such as G codes, M codes, and S codes. In the machining formula, a command statement is recorded in each line. The command statement in each line is called a block. In addition, the variable contained in the command statement is called a word.

FIG9 shows the command statements for rotating and stopping the spindle motor. In machining formula 75, the command statement M03 on the first line is an M code indicating that the spindle is rotated in the positive direction. The command statement S2000 on the second line is an S code indicating the target rotation speed of the spindle. The command statements on the first and second lines indicate that the spindle is rotated in the positive direction until the motor rotation speed reaches 2000 rpm.

The G04 instruction statement in the third line is a G code indicating the pause function. The G04 instruction statement indicates the instruction to stop the machining process while the machine tool is running. The variable P1000 indicates the instruction to stop the machining process for 1000 msec. The M05 instruction statement in the next line indicates the instruction to stop the spindle. The machining process is stopped for 1000 msec by the G04 instruction statement in the next line. The M99 instruction statement in the last line is an M code indicating the end of the subroutine. In this way, in machining process 75, the instruction statement is formed by the code and the variable (argument) related to the code.

FIG10 shows an estimation program in the estimation control of the spindle motor. The estimation program 75a is generated corresponding to the machining formula 75 shown in FIG9. The estimation program of this embodiment is an instruction statement for driving the machining formula of the machine tool, and an auxiliary variable indicating the load factor of the motor is added. The load factor of the motor is the ratio of the output torque to the rated torque.

In the estimation program 75a, the first auxiliary variable (spindlepower) used to accelerate or decelerate the spindle motor is recorded in the command statement M03 on the first line and the command statement M05 on the fourth line. The first auxiliary variable is a variable related to the load factor and used to change the rotation speed of the motor. Each first auxiliary variable is displayed as "spindlepower100%" or "spindlepower-100%". For example, in the command statement M03 on the first line, a command to accelerate the spindle motor with a load factor of 100% is recorded based on the first auxiliary variable added to the command statement of the processing formula 75.

In the G04 command statement on the 3rd line and the G04 command statement on the 5th line, the second auxiliary variable (spindlecutpower) related to the load factor for machining the workpiece is recorded. In the present embodiment, the rotation speed of the motor is fixed while the workpiece is being machined. The load factor corresponding to the cutting torque of the workpiece is displayed in the second auxiliary variable. Here, "spindlecutpower50%" which displays the load factor of the spindle motor during cutting is recorded in the G04 command statement on the 3rd line as the second auxiliary variable. That is, it is displayed that the workpiece is cut with a load factor of 50% of the spindle motor. In addition, since the cutting has been completed in the G04 command statement on the 5th line, "spindlecutpower0%" is recorded. Such a load factor of the motor can be determined in advance by the operator who performs the simulation. The estimation program 75a is formed by adding the first auxiliary variable and the second auxiliary variable to the instruction statement of the processing formula 75.

Figure 11 is a graph showing the output characteristics of the spindle motor. The output characteristics of the motor show the relationship between the output of the motor and the rotation speed when the motor is driven at a 100% load rate. The horizontal axis shows the rotation speed of the spindle motor, and the vertical axis shows the output of the spindle motor. The output is proportional to the rotation speed up to about 7000rpm.

Referring to FIG8 , in the estimation control of the spindle motor, the speed estimation unit 84 of the calculation unit 83 calculates the angular acceleration of the spindle motor based on the first auxiliary variable. The speed estimation unit 84 estimates the change of the rotation speed of the spindle motor over time. That is, the speed estimation unit 84 calculates the change of the rotation speed of the spindle motor in a time series manner. Furthermore, the speed estimation unit 84 estimates the time until the spindle motor reaches the target rotation speed based on the change of the rotation speed over time.

FIG12 shows a timing diagram of the spindle motor driving state estimated by the estimated control of the spindle motor. Referring to FIG10 and FIG12, from time t0 to time t1, the rotation speed of the spindle motor increases according to the command statements of M03 and S2000. According to the command statement of S2000, the rotation speed is accelerated to 2000rpm. The load factor for the acceleration of the spindle at this time is set to 100% by the first auxiliary variable "spindlepower100%" added to the command statement of M03.

From time t1 to time t2, the rotation speed is maintained for 1 second according to the G04 command statement on line 3. The duty factor of the spindle motor for cutting from time t1 to time t2 is set to 50% by the second auxiliary variable. From time t2 to time t3, the duty factor is decelerated by -100% according to the first auxiliary variable of the M05 command statement. After time t3, the duty factor for cutting is maintained at 0% for 1 second according to the second auxiliary variable of the G04 command statement on line 5.

Figure 11 shows a graph of output characteristics when the load factor is 100%. When the spindle motor rotates at about 7000 rpm, the output increases in proportion to the rotation speed. Since the motor output is calculated by multiplying the rotation speed by the torque, the motor output torque is fixed before the rotation speed reaches 7000 rpm.

Here, according to the G04 instruction statement of the estimation program 75a, the time length from time t1 to time t2 and the time length from time t3 to time t4 are 1 second. However, since the time (time constant) until the target rotation speed of the spindle motor is reached is not determined in advance, the speed estimation unit 84 calculates the change of the rotation speed of the spindle motor in a time series manner.

The speed estimation unit 84 calculates the angular acceleration of the spindle motor during the period from time t0 to time t1. The speed estimation unit 84 calculates the output of the spindle motor corresponding to the rotation speed based on the output characteristics of the spindle motor shown in FIG. 11. Here, the speed estimation unit 84 calculates the output of the spindle motor corresponding to the rotation speed of 2000 rpm as shown by arrows 95 and 96. In this example, since the load factor for accelerating the spindle motor is set to 100% by the first auxiliary variable, the output of the spindle motor obtained from FIG. 11 can be used. In addition, when the acceleration duty factor of the spindle motor is less than 100% due to the first auxiliary variable, the output of the spindle motor can be calculated based on the output of the spindle motor and the acceleration duty factor obtained from FIG. 11 .

Next, the speed estimation unit 84 divides the output of the main shaft motor by the rotation speed to calculate the torque of the main shaft motor. Then, the speed estimation unit 84 divides the torque of the main shaft motor by the inertia to calculate the angular acceleration, and the aforementioned inertia includes the inertia of the motor rotor and the inertia of the load applied to the motor. The slope of the graph of the rotation speed from time t0 to time t1 is equivalent to the angular acceleration. The speed estimation unit 84 can calculate the time length SX1 from time t0 to time t1 based on the final rotation speed and angular acceleration. In addition, the speed estimation unit 84 can calculate the time t1.

The speed estimation unit 84 can also calculate the angular acceleration during deceleration in the interval from time t2 to time t3 by the same control. The speed estimation unit 84 can calculate the time length SX2 from time t2 to time t3. The speed estimation unit 84 can calculate time t3 based on time t2 and time length SX2. In addition, the calculation unit 83 can estimate the time length (cycle time) of the machine tool operation from time t0 to time t4 based on time lengths SX1 and SX2. That is, the calculation unit 83 can calculate the time from the start to the stop of the motor based on the machining process.

In this way, the speed estimation unit 84 can estimate the change of the rotation speed over time based on the angular acceleration. In addition, the speed estimation unit 84 can calculate the time until the spindle motor reaches the target rotation speed based on the angular acceleration. In addition, the speed estimation unit 84 can estimate the change of the rotation speed of the motor over time from the start to the stop of the motor.

In the estimated control of the spindle motor, in order to calculate the rotation speed of the motor, an instruction statement can be generated in which the first auxiliary variable is added as the load factor for accelerating the motor to the instruction statement of the processing formula. In addition, the angular acceleration when the motor is accelerated or decelerated can be estimated based on the output characteristics and inertia of the motor. In addition, an instruction statement can be generated in which the second auxiliary variable is added as the load factor corresponding to the cutting torque of the spindle motor to the instruction statement during the period of cutting the workpiece. The second auxiliary variable can be used to determine the load factor during the period of cutting the workpiece from moment t1 to moment t2. The calculation unit 83 can estimate the change in the load factor of the motor over time from the start to the stop of the motor.

Next, the estimation control of the driving state of the feed shaft motor of the motion estimation device 81 of this embodiment is explained. In the estimation control of the feed shaft motor, the driving state of the feed shaft motor is estimated. The time constant of the feed shaft motor is determined in advance. The time constant corresponds to the angular acceleration when the feed shaft motor is accelerated or decelerated. The time constant of the motor is determined by, for example, the control software that controls the motor. In the estimation control of the feed shaft motor, the torque output by the feed shaft motor when accelerating according to a fixed angular acceleration is estimated. In this embodiment, the load rate of the feed shaft motor is estimated. In the estimation control of the feed shaft motor, the temporal change in the rotation speed of the feed shaft motor and the change in the position of the object driven by the feed shaft motor are estimated.

FIG. 13 shows the instruction statement recorded in the estimation program in the estimation control of the feed shaft motor. In estimation program 76a, the G01 instruction statement is recorded to drive the feed shaft motor. The G01 instruction statement of estimation program 76a is an instruction statement in which an auxiliary variable is recorded in the G01 instruction statement of the machining program. The G01 instruction statement indicates the instruction to move the table linearly. In this instruction statement, the movement of the table that fixes the workpiece in the X-axis direction is displayed.

In the machine tool of this embodiment, a mechanical coordinate system is determined so that the spindle head 6 and the table do not move even if they move. In the G01 command statement, the target position of the table is displayed in the mechanical coordinate system. In the G01 command statement, there is a command to move the table so that the coordinate value of the X axis and the coordinate value of the Y axis of the mechanical coordinate system become 10 and 10, respectively. In addition, F1000 is a variable that displays the target moving speed when the table moves. Here, it is recorded that the table is moved at a speed of 1000 mm/min.

In the estimation program 76a, a third auxiliary variable related to the load factor used to process the workpiece is added to the G01 instruction statement used in the machining program. Here, as the third auxiliary variable, "servocutpower10%" which shows the load factor of the feed shaft motor during cutting is added after the G01 instruction statement of the machining program. This load factor is equivalent to the torque instruction during cutting. The third auxiliary variable here shows the situation where the load factor of the feed shaft motor during cutting the workpiece is 10%.

Fig. 14 is a graph showing the output characteristics of the feed shaft motor. Similar to the graph of the spindle motor in Fig. 11, the graph of Fig. 14 shows the relationship between the rotation speed and the output of the feed shaft motor at a total load factor of 100%.

8, the torque estimation unit 85 of the calculation unit 83 calculates the change of the load factor of the motor during operation with time based on the time constant of the feed shaft motor, the output characteristics of the feed shaft motor, the instruction statement having the third auxiliary variable included in the estimation program 76a, and the inertia related to the driving of the motor. As described later, the torque estimation unit calculates the load factor when the feed shaft motor is accelerated or decelerated.

FIG. 15 shows a timing diagram of the driving state of the feed shaft motor estimated by the estimated control of the feed shaft motor. Here, an example of moving the worktable of the machine tool in the direction of the X-axis is shown. From time t0 to time t5, the rotation speed of the feed shaft motor increases. From time t5 to time t6, the feed shaft motor is maintained at a fixed rotation speed C. Furthermore, from time t6 to time t7, the rotation speed of the feed shaft motor decreases. The position of the worktable in the X-axis direction moves from the current position to a position with a coordinate value of 10 on the X-axis.

The target rotation speed C of the feed shaft motor when the table is moved in the direction of the X axis can be calculated based on the variable F1000 in the G01 instruction statement of the estimation program 76a. The variable F1000 shows that the target movement speed of the table is 1000 mm/min. The calculation unit 83 can calculate the target rotation speed C of the feed shaft motor of the X axis based on the target movement speed of the table and the information 72 of the moving device such as the pitch of the ball screw of the ball screw mechanism that moves the table in the X axis direction. In addition, although the example in which the table moves in the X axis direction is shown here, it is not limited to this form. When the table moves in the Y-axis direction in addition to the X-axis direction, the rotation speed of the Y-axis feed shaft motor can be calculated based on the table's Y-axis movement speed and the information of the Y-axis moving device. In addition, the drive state of the motor can be estimated for the Y-axis feed shaft motor by the same control as the X-axis feed shaft motor.

The calculation unit 83 calculates the angular acceleration from the time constant determined in the feed shaft motor. The calculation unit 83 can calculate the change of the rotation speed over time in the interval from time t0 to time t5. The calculation unit 83 can calculate the time length SL1 from time t0 to time t5 for reaching the target rotation speed C based on the change of the rotation speed. In addition, the calculation unit 83 can calculate the change of the rotation speed over time and the time length SL3 in the interval from time t6 to time t7 based on the angular acceleration.

The calculation unit 83 can integrate the rotation speed of the feed shaft motor to calculate the rotation position of the feed shaft motor at time t5 and time t6. In addition, the calculation unit 83 can calculate the position of the worktable on the X-axis corresponding to the rotation position of the feed shaft motor based on the information 72 of the moving device. The calculation unit 83 can calculate the position of the object driven by the feed shaft motor. The calculation unit 83 can calculate the movement distance in the X-axis direction from time t5 to time t6 based on the rotation position of the feed shaft motor or the position of the worktable in the X-axis direction. In addition, the calculation unit 83 can calculate the time length SL2 from time t5 to time t6 based on the movement distance in the X-axis direction and the fixed rotation speed C. The calculation unit 83 can estimate the time length (cycle time) of the machine tool operating from time t0 to time t7. In addition, the calculation unit 83 can calculate the times t5, t6, and t7 based on the time lengths SL1, SL2, and SL3.

In this way, the calculation unit 83 can estimate the change in the rotation speed of the feed shaft motor and the change in the position of the table in the X-axis direction from the start to the end of the table movement. In addition, the calculation unit 83 can estimate the length of time from the start to the end of the table movement.

Next, in the estimation control of the feed shaft motor, the torque estimation unit 85 of the calculation unit 83 calculates the temporal change of the load factor when the feed shaft motor is operating. In the present embodiment, the torque estimation unit 85 calculates the load factor (TX1) when the feed shaft motor is accelerating or decelerating.

Referring to FIG. 14 and FIG. 15 , in the interval between time t0 and time t5, the torque estimation unit 85 multiplies the inertia related to the driving of the motor by the angular acceleration to calculate the torque required for acceleration. Referring to the output characteristics of the motor in FIG. 14 , the torque estimation unit 85 calculates the output when the load factor is 100% according to the target rotation speed C as shown by arrows 97 and 98. The torque estimation unit 85 divides the output when the load factor is 100% by the rotation speed to calculate the torque when the load factor is 100%. The torque estimation unit 85 can divide the torque required for acceleration by the torque when the load factor is 100% to calculate the load factor TX1 of the feed shaft motor. The load factor here is equivalent to the torque command of the feed shaft motor of the machine tool.

In this way, the torque estimation unit 85 calculates the load factor (TX1) shown in Fig. 15. The load factor (-TX1) during deceleration from time t6 to time t7 can also be calculated by the same control.

The load factor of the feed shaft motor during the machining of the workpiece by the machine tool can be set in advance by the operator who performs the simulation. The operator can estimate the load factor during machining based on the information of the tool and the information of the workpiece. Referring to FIG. 13 , the operator specifies the load factor of the feed shaft motor during cutting as the third auxiliary variable in the estimation program 76a. In this example, the load factor of the feed shaft motor during cutting is 10%.

Referring to FIG. 15 , the torque estimation unit 85 sets the load factor of the feed shaft motor during the processing of the workpiece according to the third auxiliary variable recorded in the instruction statement of the estimation program 76a. The torque estimation unit 85 sets the load factor of the feed shaft motor to 10% in the interval from time t5 to time t6. As a result, the torque estimation unit 85 can estimate the change of the load factor over time from the start to the stop of the feed shaft motor. That is, the change of the load factor of the feed shaft motor from the start to the end of the movement of the worktable can be estimated. In this way, the driving state of the feed shaft motor can be calculated in the estimation control of the feed shaft motor.

However, in the estimation control of the feed shaft motor, when the torque estimation unit 85 has calculated the torque required for acceleration, the torque required for acceleration may exceed the rated torque. In other words, the load factor may exceed 100%. When the variable estimated by the calculation unit 83 exceeds the pre-determined allowable range, the determination unit 86 of the calculation unit 83 implements control to notify the operator who performs the simulation of the motor.

In the present embodiment, the determination unit 86 determines whether the load factor estimated by the torque estimation unit 85 exceeds the permissible range. The permissible range of the load factor is predetermined to be greater than 0% and less than 100%. In particular, the determination unit 86 determines whether the load factor exceeds 100%. Furthermore, when the load factor exceeds 100%, the determination unit 86 may output a text file as a control to notify the operator, and the text file may record a warning that the load factor has exceeded the permissible range. Alternatively, the determination unit 86 may include the warning in the file of the result of the estimated driving state of the motor.

Alternatively, the determination unit 86 may send a signal corresponding to the information that the load factor of the motor exceeds the allowable range to the display control unit 87. The display control unit 87 may display on the display unit 88 that the machine tool cannot be driven under the current conditions. Alternatively, the display control unit 87 may display on the display unit 88 that the load factor of the feed shaft motor exceeds the allowable range.

The control for notifying the operator who is performing the simulation of the warning is not limited to the control for outputting a file recording the warning or the control for displaying the information on the display unit, and any control may be adopted. For example, the operator may be notified by sound that the machine tool cannot be driven.

The motion estimation device 81 of this embodiment can estimate the driving state of the motor such as the rotational speed, angular acceleration, and load factor of the motor without actually driving the machine tool. The driving state of the motor calculated by the calculation unit 83 can be stored in the storage unit 82. In addition, the operator can confirm that there is no problem in driving the machine tool or change the conditions for driving the machine tool based on the estimated driving state of the motor.

(Simulation of the motor and setting of the action of the blower) Next, the simulation of the motor driving state performed by the simulation execution unit of the simulation device and the simulation results are explained to set the action of the blower of the motor.

FIG. 16 shows a timing chart of the simulation result of the temperature of the components of the motor of the present embodiment. Here, the driving state of the spindle motor when the machine tool cuts the workpiece at a predetermined interval is exemplified. The driving state of the motor repeats the state of a load factor of 100% and the state of a load factor of 0% at a predetermined interval. When the load factor is 100%, the workpiece is cut, and when the load factor is 0%, the tool runs idle. For example, at time _t11 , the load factor starts to increase and changes from 0% to 100%, and at time _t12 , the load factor starts to decrease and changes from 100% to 0%. For example, the rotation speed of the motor 10 decreases from 5000 rpm to 500 rpm at time _t11 , and increases from 500 rpm to 5000 rpm at time _t12 .

Referring to FIG3, in step 102, the motion estimation device 81 estimates the driving state of the motor according to the motion program 45. In the timing diagram of FIG16, when the rotation speed increases from 500 rpm to 5000 rpm, or decreases from 5000 rpm to 500 rpm, as shown in FIG12, the rotation speed changes at a predetermined slope. The operator generates the estimation program 71 according to the processing formula as the motion program 45. The motion estimation device 81 calculates the driving state of the motor including the rotation speed and the load factor of the motor in a time series manner according to the estimation program 71.

The motion estimation device 81 can calculate the driving state of the motor at a predetermined time interval. For example, the motion estimation device 81 calculates the rotation speed and load factor of the motor at each time interval when the simulation execution unit 64 performs the simulation. Referring to FIG. 1 , the information 69 of the driving state of the motor estimated by the motion estimation device 81 is stored in the memory unit 51 of the simulation device 2.

Referring to FIG3 , in step 103, the temperature estimation unit 53 of the simulation execution unit 64 estimates the temperature of the components of the motor including the estimated temperature of the stator core 20. The action setting unit 65 of the simulation execution unit 64 sets the action of the blower 29 of the motor 10 according to the temperature change of the stator core 20. FIG16 shows the estimated temperature of the coil, the estimated temperature of the rotor, and the estimated temperature of the stator core estimated by the temperature estimation unit 53. FIG16 also shows the driving state including the action of the blower 29 set by the action setting unit 65.

The operation of the blower 29 is determined to be an ON state and an OFF state. When the blower 29 is in the ON state, the blower 29 is operated at the maximum rotation speed. When the blower 29 is in the OFF state, the blower 29 stops.

In this embodiment, as described above, the model of the first motor when the blower 29 of the motor 10 is driven at the maximum rotation speed and the model of the second motor when the blower 29 of the motor 10 is stopped are prepared in advance by the parameter setting unit 57. Thus, in this embodiment, the model of the motor is prepared based on the driving state of the blower 29 when the machine is actually driven.

1 , the simulation execution unit 64 includes a temperature estimation unit 53. The loss calculation unit 54 of the temperature estimation unit 53 calculates the copper loss of the coil and the iron loss of the stator core according to the load factor and the rotation speed of the motor set by the action estimation device 81. That is, the heat generated in the coil and the heat generated in the stator core are calculated. The temperature calculation unit 55 calculates the temperature of each component included in the motor according to the loss calculated by the loss calculation unit 54 using the model of the motor.

The temperature calculation unit 55 estimates the temperature of the components of the motor 10 using the motor model corresponding to the driving state of the blower 29. In this example, when the blower is turned on (ON), the model of the first motor when the blower 29 is driven at the maximum rotation speed is used. When the blower is turned off (OFF), the model of the second motor when the blower 29 is stopped is used.

The action setting unit 65 of the simulation execution unit 64 obtains the estimated temperature of the stator estimated by the temperature estimation unit 53. In this embodiment, the estimated temperature of the stator core is used as the estimated temperature of the stator. The temperature of the stator is not limited to the temperature of the stator core, and the temperature of any component constituting the stator can be used. For example, the temperature of the coil can be used. Alternatively, when the stator has a frame surrounding the stator core, a model of the motor including the stator frame can be made. In addition, the temperature of the stator frame calculated by the motor model can also be used as the stator temperature.

The action setting unit 65 calculates the rate of change per unit time of the estimated temperature of the stator core 20 at predetermined time intervals. That is, the action setting unit 65 calculates the slope of the estimated temperature of the stator core 20. The action setting unit 65 sets the action of the blower 29 of the motor 10 according to the slope of the estimated temperature of the stator core 20. That is, the action of the blower 29 is changed according to the temperature increase or temperature decrease per unit time of the estimated temperature of the stator core 20.

The action setting unit 65 of this embodiment is set to stop the blower 29 when the absolute value of the slope of the estimated temperature rise of the stator core 20 is less than a predetermined judgment value. That is, when the cooling effect of the blower becomes larger relative to the heat generated by the motor and the temperature rise rate becomes slower, the blower 29 is stopped. In addition, the action setting unit 65 is set to start the blower 29 when the absolute value of the slope of the estimated temperature drop of the stator core 20 is less than a predetermined judgment value. That is, when the heat generated increases relative to the heat dissipated by the motor and the temperature drop rate becomes slower, the blower 29 is started. In the present embodiment, the control of changing the driving state of the blower according to the slope of the estimated temperature of the components of the motor such as the stator is referred to as the control of the operation of the blower.

In the example shown in FIG. 16 , after the load factor is increased at time _t11 , at time _t21 , the absolute value of the temperature drop rate of the stator core 20 is less than the judgment value. Therefore, the blower 29 is started at time _t21. Moreover, after the load factor is reduced at time _t12 , at time _t22 , the absolute value of the temperature rise rate of the stator core 20 is less than the judgment value. Therefore, the blower 29 is stopped at time _t22 . In this way, the action setting unit 65 sets the period for switching the drive state of the blower 29 between the ON state and the OFF state. In addition, the temperature estimation unit 53 estimates the temperature of the component parts using the model of the motor, and the aforementioned motor model corresponds to the driving state of the motor set by the action setting unit 65.

The temperature of the components of the motor when actually driving the machine corresponds to the estimated temperature of the components when the simulation is performed. The estimated temperature of the coil increases when the load factor of the motor is 100%, and decreases when the load factor of the motor is 0%. The estimated temperature of the rotor 11 and the estimated temperature of the stator core 20 change slightly later than the change in the estimated temperature of the coil 16. As a result, the blower 29 of the motor 10 starts and stops slightly delayed from the change in the load factor. The action of the blower 29 is to repeat the on (ON) state and the off (OFF) state.

By setting the action of the blower performed by the action setting unit 65 of this embodiment, the temperature fluctuation range ΔT ₂₁ of the stator core 20 becomes smaller. The difference between the maximum temperature and the minimum temperature of the stator core 20 in a predetermined period can be calculated as the fluctuation range. As the predetermined period, the period after the stator core temperature rise ends and the temperature of the stator core is almost constant after the motor is started can be used. For example, the period in which the temperature of the stator core changes within the predetermined temperature range can be determined. In Figure 16, the interval from time t ₁₁ to time t ₂₆ can be determined. In this example, the temperature fluctuation range ΔT ₂₁ of the stator core 20 is 1.2°C.

FIG. 17 shows a timing chart of the simulation result of the motor of the first comparative example. In the first comparative example, the blower 29 is continuously driven at a predetermined fixed rotation speed regardless of the load factor of the motor 10 and the temperature of the components of the motor 10. In this example, the blower 29 is not stopped but driven at the maximum rotation speed. That is, the action setting unit 65 does not determine the action of switching the blower 29.

In order to perform simulation corresponding to the driving state of the blower 29 of the motor 10, the temperature estimating unit 53 estimates the temperature of the components of the motor using a model of the motor when the blower 29 is driven at the maximum rotation speed. FIG17 shows the estimated temperature of the coil 16, the estimated temperature of the rotor 11, and the estimated temperature of the stator core 20.

When the control of the operation of the blower shown in FIG. 16 is implemented, the maximum value of the temperature of the coil 16 is higher than the maximum value of the temperature of the coil 16 when the blower 29 is driven all the time as shown in FIG. 17. Moreover, the average value of the temperature of the rotor 11 and the average value of the temperature of the stator core 20 are higher when the control of the operation of the blower is implemented than the values when the blower is driven all the time. The fluctuation range ΔT ₂₂ of the estimated temperature of the stator core 20 in the simulation of the first comparative example is 4°C during the period from time t ₁₁ to time t ₁₆ .

FIG18 shows a timing diagram of the simulation result of the motor of the second comparative example. In the second comparative example, the operation of the blower 29 is changed in accordance with the change in the load factor of the motor 10. In the example shown in FIG18, when the load factor of the motor 10 is 100%, the blower 29 is driven at the maximum rotation speed. When the load factor of the motor 10 is 0%, the blower 29 is stopped. When the load factor of the motor 10 is 100%, the temperature estimation unit 53 estimates the temperature of the components of the motor 10 using a model of the motor when the blower 29 is driven at the maximum rotation speed. Furthermore, when the load factor of the motor 10 is 0%, the temperature estimating unit 53 estimates the temperature of the components of the motor 10 using a model of the motor when the blower 29 is stopped.

In the second comparative example, the operation of the blower is not determined based on the change rate of the temperature of the stator core 20 of the operation setting unit 65, but the operation of the blower is changed as the load factor changes. The variation range ΔT ₂₃ of the estimated temperature of the stator core ₂₀ in this simulation is 1.9°C during the period from time t11 to time _t16 .

16 to 18, when the action of the blower is determined by the action setting unit 65 of the present embodiment, the variation range _ΔT21 of the estimated temperature of the stator core is smaller than the variation range _ΔT22 of the estimated temperature in the first comparison example and the variation range _ΔT23 of the estimated temperature in the second comparison example. More specifically, the variation range _ΔT23 of the estimated temperature when the action of the blower and the change in the load factor are changed simultaneously (the second comparison example) is smaller than the variation range _ΔT22 of the estimated temperature when the blower is always driven (the first comparison example). Furthermore, the fluctuation range _ΔT21 during the control of the operation of the blower in the present embodiment is smaller than the fluctuation range _ΔT23 of the estimated temperature in the second comparative example.

In this way, by controlling the operation of the blower according to the present embodiment, the temperature fluctuation range of the stator core 20 can be reduced. In other words, the temperature fluctuation range of the motor 10 can be reduced.

Since the temperature fluctuation range of the motor 10 becomes smaller, the thermal displacement of the components of the machine that the motor 10 contacts can be reduced. As a result, the accuracy of the driving machine can be improved. For example, there may be a case where the motor is a spindle motor configured on the spindle head of a machine tool. A spindle for holding the tool is configured on the spindle head. Therefore, there may be a case where the heat of the motor is transferred to the spindle. When the temperature fluctuation range of the motor is large, the temperature fluctuation range of the spindle will increase. The thermal displacement of the spindle will increase, and there is a concern that the position of the front end point of the tool will be displaced. As a result, there is a concern that the accuracy of the processed workpiece will deteriorate.

By reducing the fluctuation range of the temperature of the motor, the temperature fluctuation of the spindle will also be reduced, and the thermal displacement of the spindle can be reduced. As a result, the displacement of the position of the tip point of the tool can be suppressed. Alternatively, there may be a situation where the position of the tip point of the tool is corrected in response to the driving state of the motor. In this case, by reducing the temperature fluctuation of the spindle, it is not necessary to change the correction amount of the position of the tip point of the tool in response to the driving state of the spindle. Alternatively, the correction amount of the position of the tip point of the tool can be set to be fixed. Alternatively, there is no need to correct the position of the tip point of the tool.

Moreover, when the blower 29 is always driven, the power consumption of the motor 10 increases. When the control of the operation of the blower of this embodiment is performed, since a period of stopping the blower 29 is generated, the power consumption of the motor 10 can be suppressed.

The action setting unit 65 of this embodiment sets the action of the blower according to the slope of the estimated temperature of the stator. The temperature of the stator will rise due to copper loss of the coil and iron loss of the stator core. The stator may contact the components of the machine. By suppressing the temperature fluctuation of the stator, the thermal displacement of the components of the machine can be suppressed.

Furthermore, the stator core may contact the components of the machine or be arranged close to the components of the machine. Therefore, the estimated temperature of the stator core is used as the estimated temperature of the stator, thereby estimating the heat transferred to the components of the machine with good accuracy.

In addition, the action setting unit 65 is a slope for determining the temperature of the stator. In determining the temperature of the stator, the relationship between the heat generation and the heat dissipation is unknown. However, by determining the slope of the temperature of the stator, the heat generation per unit time and the heat dissipation per unit time of the motor can be directly compared. In the control of the action of the blower in this embodiment, the variation range of the stator temperature can be reduced compared to the control (the second comparison example) in which the driving state of the blower is changed in accordance with the change of the load factor.

(Auxiliary program generation unit) Referring to FIG. 3 , in step 104 , the simulation execution unit 64 is an auxiliary program for creating the action of the blower 29 . Referring to FIG. 1 , the auxiliary program generation unit 66 of the simulation execution unit 64 is to generate an auxiliary program so that when the machine 1 is actually driven, the action of the blower 29 set by the action setting unit 65 can be implemented. In the auxiliary program, for example, the action of the blower 29 corresponding to the action instruction output by the action control unit 43 according to the action program 45 is recorded.

For example, in the control of the operation of the blower in Fig. 16, the auxiliary program is created so that the blower 29 is activated after a time difference Δt has passed since the operation command of the load factor 100% was issued. The time difference Δt is, for example, (time _t21 - time _t11 ), which can be calculated based on the simulation result.

The auxiliary program is stored in the memory unit 42 of the machine control device 41. When the machine 1 is actually driven, the motion control unit 43 drives the motor 10 according to the motion program 45. In addition, the motion control unit 43 controls the motion of the blower 29 according to the motion command of the motor 10 and the auxiliary program.

In the above form, although the auxiliary program is created by the simulation execution unit to control the movement of the blower based on the movement of the motor in the action program, the present invention is not limited to this form. For example, the simulation execution unit may also add the instruction statement of the movement of the blower to the action program. For example, in addition to the instruction statement of the movement of the motor in the action program 45, the instruction statement of the movement of the blower may also be recorded in a manner corresponding to the driving state of the motor. Here, the generation of the auxiliary program or the modification of the action program may also be implemented by the simulation execution unit of the simulation device or the operator.

(Variation Range Comparison Unit and Power Consumption Comparison Unit) Referring to FIG. 1 , the variation range comparison unit 67 of the simulation execution unit 64 calculates the variation range of the stator temperature during a predetermined period. The difference between the maximum value and the minimum value of the estimated temperature of the stator core 20 can be calculated as the variation range as described above. Referring to FIG. 16 and FIG. 17 , the variation range comparison unit 67 calculates a variable for comparing the variation range based on the variation range ΔT ₂₁ when the fan is controlled and the variation range ΔT ₂₂ when the fan is driven at a predetermined fixed rotation speed.

The difference in the variation range (ΔT ₂₂ - ΔT ₂₁ ) obtained by subtracting the variation range ΔT ₂₁ from the variation range ΔT ₂₂ can be calculated as a variable for comparing the variation ranges. Alternatively, the variation range ratio (ΔT _{21 / ΔT 22 ) obtained by dividing the variation range ΔT 21 by the} variation range ΔT ₂₂ can be calculated as a variable for comparing the variation ranges.

The coefficient related to the difference in the variation amplitude can be calculated by the variation amplitude comparison unit 67 to determine whether to implement the control of the action of the blower. For example, even if the control of the action of the blower shown in FIG. 16 is implemented, there may be a case where the variation amplitude of the temperature of the motor 10 cannot be sufficiently reduced. In this case, it can be determined that the control of the action of the blower in this embodiment is not implemented. This determination can be made by the variation amplitude comparison unit or the operator.

Alternatively, the accuracy of the driving machine can be estimated based on a coefficient related to the difference in the amplitude of variation. When the amplitude of variation of the estimated temperature of the stator core is sufficiently small, it can be determined that the driving accuracy of the machine is high. For example, it can be determined that it is not necessary to correct the position of the tip point of the tool according to the driving state of the spindle motor of the machine tool. This determination can be made by the amplitude of variation comparison department or the operator.

The variation range comparison unit 67 can calculate a variable for comparing the variation range in any driving state of the motor. In particular, it is desirable that the variation range comparison unit 67 calculates a variable for comparing the variation range during a period in which the estimated temperature of the stator core 20 is almost constant. For example, after the motor 10 is started from a state of long-term stop, the temperature of the motor components such as the stator core gradually rises from room temperature. When the motor operation state has become a stable state or a state in which a predetermined operation mode is repeated, the variation range of the estimated temperature of the stator core becomes almost constant.

Whether the estimated temperature of the stator core is almost fixed is determined, for example, by calculating the fluctuation range at predetermined time intervals. And, when the fluctuation range gradually decreases and becomes smaller than the predetermined judgment value, it can be determined that the estimated temperature of the stator core is almost fixed. Alternatively, the moving average of the estimated temperature of the stator core is calculated at each predetermined time interval. At this time, when the difference between the last moving average and the current moving average becomes smaller than the predetermined judgment criterion, it can be determined that the estimated temperature of the stator core has become almost fixed. By comparing the fluctuation range when the estimated temperature of the stator core is almost fixed, the effect of controlling the action of the blower can be accurately determined.

Referring to FIG. 1 , the power consumption comparison unit 68 of the simulation execution unit 64 calculates the power consumption of the blower during a predetermined period. The power consumption comparison unit 68 calculates a variable for comparing power consumption based on the power consumption when the blower is controlled (the control of FIG. 16 ) and the power consumption when the blower is driven at a predetermined fixed rotation speed (the control of FIG. 17 ). The variable for comparing power consumption can be calculated by subtracting the power consumption when the blower is controlled from the power consumption when the blower is driven at a fixed rotation speed. Alternatively, the variable can be calculated by dividing the power consumption when the blower is controlled by the power consumption when the blower is driven at a fixed rotation speed.

By calculating the variable used to compare power consumption, the amount of power consumption reduction caused by the implementation of the control of the action of the blower can be known. In addition, it can be determined whether to implement the control of the action of the blower based on the reduction in power consumption. For example, when the power consumption is not sufficiently small, it can be determined that the control of the action of the blower is not implemented. This determination can be made by the power consumption comparison unit or the operator.

In the aforementioned embodiment, as the action of the blower 29, although the state of being driven at a predetermined fixed rotational speed and the state of the blower 29 being stopped are exemplified, it is not limited to this form. The action setting unit can arbitrarily set the action of the blower according to the slope of the estimated temperature of the stator estimated by the temperature estimation unit. For example, the action setting unit sets the action of the blower so that the greater the absolute value of the slope of the estimated temperature rise of the stator estimated by the temperature estimation unit, the greater the rotational speed of the blower. Alternatively, the action of the blower can be set so that the greater the absolute value of the slope of the estimated temperature drop of the stator estimated by the temperature estimation unit, the smaller the rotational speed of the blower.

In particular, the action setting unit may also be configured to continuously change the rotation speed of the blower in accordance with the slope of the estimated temperature of the stator. Alternatively, the action setting unit may be configured to change the rotation speed of the blower in stages in accordance with the slope of the estimated temperature of the stator.

In addition, when the rotation speed of the motor is to be changed, the temperature calculation unit may use a model of the motor corresponding to the rotation speed of the blower. For example, a plurality of rotation speed ranges of the blower are determined in advance, and the parameter setting unit may create a model of the motor using a rotation speed in the middle of each rotation speed range. The temperature calculation unit may switch the model of the motor in accordance with the rotation speed of the blower when performing the simulation of the motor.

Referring to FIG. 1 , the simulation device 2 of this embodiment is composed of a different operation processing device from the mechanical control device 41. For example, although the simulation device 2 is composed of a laptop computer, it is not limited to this form. The mechanical control device 41 can have the function of the simulation device 2. That is, the mechanical control device 41 can also include a simulation execution unit 64, a parameter setting unit 57, a memory unit 51, and a display unit 52.

The mechanical control device may include the above-mentioned simulation device and an action control unit that generates action instructions for driving the machine. Furthermore, the action control unit may output action instructions for the blower to implement the action of the blower set by the simulation device. For example, the action control unit may drive the blower of the motor according to the auxiliary program generated by the auxiliary program generation unit. By adopting this structure, the temperature fluctuation range of the motor can be reduced to suppress the thermal displacement of the components of the machine. As a result, the accuracy of the driving state of the machine can be improved. In addition, the power consumption of the motor can be suppressed.

According to at least one embodiment as described above, a simulation device and a machine control device having the simulation device can be provided, wherein the simulation device sets the action of the blower of the motor in response to the temperature change of the stator.

Although the present disclosure has been described in detail, the present disclosure is not limited to the above-mentioned embodiments. These embodiments can be variously added, replaced, changed, partially deleted, etc. within the scope of the main purpose of the present disclosure, or within the scope of the purpose of the present disclosure derived from the contents recorded in the patent application and its equivalents. Moreover, these embodiments can also be implemented in combination. For example, in the above-mentioned embodiments, the order of each action or the order of each processing is only shown as an example, and the embodiments are not limited to these. Moreover, the same is true when numerical values or formulas are used in the description of the above-mentioned embodiments.

The following notes are disclosed regarding the above-mentioned embodiments and modifications.

(Note 1) A simulation device is a simulation device for simulating the temperature change of a motor including a blower, the simulation device comprising: a memory unit for storing a model of the motor, wherein the model of the motor is a model for estimating the temperature of a component of the motor; a temperature estimating unit for estimating the temperature of the stator based on the model of the motor; and an action setting unit for setting the action of the blower, the model of the motor includes a model of a component of the motor and a model of external air, a heat capacity is set in the model of at least one component, a coefficient related to heat transfer is set between the models of the component of the motor and between the model of the component of the motor and the model of the external air, The action setting unit sets the action of the blower according to the rate of change per unit time of the estimated temperature of the stator estimated by the temperature estimation unit.

(Note 2) A simulation device as described in Note 1, wherein the action setting unit is set to stop the blower when the absolute value of the slope of the estimated temperature rise of the stator estimated by the temperature estimation unit is less than a predetermined judgment value, and is set to start the blower when the absolute value of the slope of the estimated temperature drop of the stator estimated by the temperature estimation unit is less than a predetermined judgment value.

(Note 3) In the simulation device described in Note 1, the action setting unit sets the rotation speed of the blower to a higher value as the slope of the estimated temperature rise of the stator estimated by the temperature estimation unit increases.

(Note 4) The simulation device as described in any one of Notes 1 to 3 has a variation amplitude comparison unit, which calculates the variation amplitude of the temperature of the stator during a predetermined period. The variation amplitude comparison unit calculates a variable for comparing the variation amplitude based on the variation amplitude when the action of the blower set by the action setting unit is controlled and the variation amplitude when the blower is driven at a predetermined fixed rotation speed.

(Note 5) The simulation device as described in any one of Notes 1 to 3 has a power consumption comparison unit, which calculates the power consumption of the blower during a predetermined period. The power consumption comparison unit calculates a variable for comparing power consumption based on the power consumption when the blower is controlled by the action setting unit and the power consumption when the blower is driven at a predetermined fixed rotation speed.

(Note 6) A simulation device as described in any one of Notes 1 to 3, wherein the temperature estimation unit includes: a loss calculation unit that calculates the heat generated by the copper loss of the coil and the heat generated by the iron loss of the stator core according to the load factor and rotation speed of the motor; and a temperature calculation unit that calculates the estimated temperature of the stator using a model of the motor based on the heat generated by the coil and the heat generated by the stator core.

(Note 7) A simulation device as described in any one of Notes 1 to 3, which has an action estimation device, the action estimation device estimates the driving state of a motor installed in a machine, The action estimation device includes a calculation unit, the calculation unit calculates a variable indicating the driving state of the motor according to a pre-made estimation program, The estimation program is a program in which auxiliary variables useful for estimating the driving state of the motor are added to the instruction statement of the action program for driving the machine, The calculation unit calculates at least one of the change in the rotation speed of the motor and the change in the load factor of the motor over time based on the output characteristics of the motor, the inertia related to the drive of the motor determined in advance, and the auxiliary variable. The temperature estimation unit estimates the temperature of the stator based on the rotation speed and the load factor of the motor calculated by the calculation unit.

(Note 8) A mechanical control device comprising: A simulation device as described in Note 1; and An action control unit that generates an action command for a motor, The action control unit outputs an action command for a blower to implement the action of the blower set by the action setting unit.

1: Machine 2: Simulation device 10: Motor 10a, 30a: Motor model 11: Rotor 11a: Rotor model 12: Stator 13: Shaft 14, 15: Bearing 16: Coil 16a: Coil model 17: Rotor core 18: Magnet 20: Stator core 20a: Stator core model 21, 22: Housing 23: Back cover 24: Bearing support member 25: Cylindrical member 26a ,26b: through hole 27: cooling fan 28: cover 28a: air hole 29: blower 31: temperature detector 31a: temperature detector model 32: rotation position detector 33: external air temperature detector 35a: air layer model 36a: external air model 41: mechanical control device 42: memory unit 43: action control unit 44: drive device 45: action program 51: memory unit 52: Display unit 53: Temperature estimation unit 54: Loss calculation unit 55: Temperature calculation unit 57: Parameter setting unit 58: State acquisition unit 59: Parameter calculation unit 60: Evaluation unit 61: Parameter change unit 64: Simulation execution unit 65: Action setting unit 66: Auxiliary program generation unit 67: Variation range comparison unit 68: Power consumption comparison unit 69: Information on the driving state of the motor 71: Estimation program 72: Information of moving device 73: Information of inertia 74: Output characteristics of motor 75: Processing formula 75a, 76a: Estimation program 81: Motion estimation device 82: Memory unit 83: Calculation unit 84: Speed estimation unit 85: Torque estimation unit 86: Determination unit 87: Control unit 88: Display unit 91, 92, 95, 96: Arrows 101, 102, 103, 104: Step C: Rotation speed C ₁ , _C2 , _C3 , _C4 , _C5 : heat capacity ha, hb, hc1, hc2, hc3, hd: coefficients related to heat transfer _Pc1 : primary copper loss _Pc2 : secondary copper loss _Pi : iron loss RA: rotation axis SL1, SL2, SL3, SX1, SX2: time length _T1 , _T2 , _T3 , _T4 , _T5 , _Tr : temperature TX1: load rate t0, t1, t2, t3, t4, _t5 , t6, t7, t11, t12, _t13 , _t14 , _t15 , _{t16 , t21} , _t22 , _t23 , _t24 , _t25 ,t ₂₆ : time ΔT ₂₁ ,ΔT ₂₂ ,ΔT ₂₃ : variation range

FIG. 1 is a block diagram of a machine and a simulation device in an embodiment. FIG. 2 is a schematic cross-sectional view of a motor in an embodiment. FIG. 3 is a flow chart for setting the action of a blower. FIG. 4 is a model of a motor in an embodiment. FIG. 5 is a timing diagram of an operation mode of a motor for explaining parameters used to set the model of the motor. FIG. 6 is a model of another motor in an embodiment. FIG. 7 is a graph of the results of a simulation using parameters set by a parameter setting unit. FIG. 8 is a block diagram of an action estimation device for estimating the driving state of a motor in an embodiment. FIG. 9 is an example of a machining formula for a spindle motor of a machine tool. FIG. 10 is an estimation program for estimating the driving state of the spindle motor by the motion estimation device. FIG. 11 is a graph showing the output relative to the rotational speed at a predetermined load rate of the spindle motor. FIG. 12 is a timing diagram showing the driving state of the spindle motor estimated by the motion estimation device. FIG. 13 is an estimation program for estimating the driving state of the feed shaft motor of the machine tool. FIG. 14 is a graph showing the output relative to the rotational speed at a predetermined load rate of the feed shaft motor. FIG. 15 is a timing diagram showing the driving state of the feed shaft motor estimated by the motion estimation device. FIG. 16 is a timing diagram showing the temperature of the components of the motor estimated by the simulation device. FIG. 17 is a timing chart showing a comparative example of the temperature of the components of the motor estimated by the simulation device. FIG. 18 is a timing chart showing another comparative example of the temperature of the components of the motor estimated by the simulation device.

101,102,103,104: Steps

Claims (8)

A simulation device is a simulation device for simulating the temperature change of a motor including a blower, the simulation device comprising: a memory unit for storing a model of the motor, the model of the motor being a model for estimating the temperature of a component of the motor; a temperature estimating unit for estimating the temperature of the stator based on the model of the motor; and an action setting unit for setting the action of the blower, the model of the motor includes a model of a component of the motor and a model of external air, a heat capacity is set in the model of at least one component, a coefficient related to heat transfer is set between the models of the component of the motor and between the model of the component of the motor and the model of the external air, The aforementioned action setting unit sets the action of the blower according to the rate of change per unit time of the estimated temperature of the stator estimated by the aforementioned temperature estimating unit. A simulation device as in claim 1, wherein the action setting unit is set to stop the blower when the absolute value of the slope of the estimated temperature rise of the stator estimated by the temperature estimation unit is less than a predetermined judgment value, and is set to start the blower when the absolute value of the slope of the estimated temperature drop of the stator estimated by the temperature estimation unit is less than a predetermined judgment value. In the simulation device of claim 1, the action setting unit sets the rotation speed of the blower to a higher value as the slope of the estimated temperature rise of the stator estimated by the temperature estimating unit is greater. A simulation device as claimed in any one of claims 1 to 3, which has a variation amplitude comparison unit, the variation amplitude comparison unit calculates the variation amplitude of the temperature of the stator during a predetermined period, The variation amplitude comparison unit calculates a variable for comparing the variation amplitude based on the variation amplitude when the action of the blower set by the action setting unit is controlled and the variation amplitude when the blower is driven at a predetermined fixed rotation speed. A simulation device as claimed in any one of claims 1 to 3, comprising a power consumption comparison unit, the power consumption comparison unit calculating the power consumption of the blower during a predetermined period, the power consumption comparison unit calculating a variable for comparing power consumption based on the power consumption when the blower action set by the action setting unit is controlled and the power consumption when the blower is driven at a predetermined fixed rotation speed. A simulation device as claimed in any one of claims 1 to 3, wherein the temperature estimating unit comprises: a loss calculating unit, which calculates the amount of heat generated by the copper loss of the coil and the amount of heat generated by the iron loss of the stator core according to the load factor and rotation speed of the motor; and a temperature calculating unit, which uses a model of the motor to calculate the estimated temperature of the stator according to the heat generated by the coil and the heat generated by the stator core. A simulation device as claimed in any one of claims 1 to 3, which has an action estimation device, wherein the action estimation device estimates the driving state of a motor installed in a machine. The action estimation device includes a calculation unit, wherein the calculation unit calculates a variable indicating the driving state of the motor according to a pre-made estimation program. The estimation program is a program in which an auxiliary variable for estimating the driving state of the motor is added to the instruction statement of the action program for driving the machine. The calculation unit calculates at least one of the change in the rotation speed of the motor and the change in the load factor of the motor over time based on the output characteristics of the motor, the inertia determined in advance and related to the driving of the motor, and the auxiliary variable. The temperature estimation unit estimates the temperature of the stator based on the rotation speed and load factor of the motor calculated by the calculation unit. A mechanical control device, comprising: a simulation device as claimed in claim 1; and an action control unit, which generates an action command of a motor, wherein the action control unit outputs an action command of a blower to implement the action of the blower set by the action setting unit.