JP2003345442A - Synchronization control unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize stabilized control without need of circuits except servomotors. <P>SOLUTION: In this unit, motor control unit models 2, 6 each of which is modeled as a servo controller are provided with each servo controller 3, 7 which controls servomotors 5, 8; the disturbance suppression is performed by making servo controllers 3, 7 operate according to each of the corresponding motor control unit model 2 or 6, and as the result the stabilized control is realized by preventing of turning into oscillation condition; and synchronization control can be realized when ball screws 10 and 11 are controlled independently in their own way without need of the circuits which correct the positions between both shafts because the constitution is made to suppress the disturbance by regarding the interference between two shafts, that is the ball screws 10, 11, as the disturbance of each shaft. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous control device for synchronously driving a plurality of servomotors based on the same position command to control the operation of one movable portion.

[0002]

2. Description of the Related Art When a heavy movable part is controlled by a single servomotor, the torque may be insufficient, and the target acceleration and speed may not be obtained. In such a case, a plurality of servomotors are synchronously driven, and one movable unit is controlled by the plurality of servomotors. A synchronous control device is used to synchronously drive a plurality of servomotors. As disclosed in Japanese Patent Application Laid-Open No. H11-305839, "Method of Controlling Plurality of Servo Motors" and the like, a conventional configuration of such a synchronous control device includes a plurality of propulsion shafts mounted on a movable portion of a device such as a ball screw. And driving control of each of the propulsion shafts is performed by a servomotor.

FIG. 6 shows the configuration of such a conventional synchronous control device. As shown in FIG. 6, the conventional synchronous control device includes servo controllers 32 and 33 and a subtractor 5.
1, comprising an adder 52, a position correction gain multiplier 31, servo motors 5 and 8, encoders 4 and 9, ball screws 10 and 11 as propulsion shafts, and a table 12 as a movable portion. I have.

In this conventional synchronous control device, a table 1
The operation of the table 12 is controlled by synchronously rotating the ball screws 10 and 11 screwed in 2 in predetermined directions by the servo motors 5 and 8, respectively.

The servo controller 32 includes a position controller 24, a speed controller 28, a current controller 29, a voltage amplifier 30, a difference calculator 37, and subtracters 48 to 50.
It is composed of Also, the servo controller 33
Comprises a speed controller 34, a current controller 35, a voltage amplifier 36, a difference calculator 38, and subtracters 53 and 54.

The subtractor 4 in the servo controller 32
9, the method of driving the servo motor 5 by the speed controller 28, the subtractor 50, the current controller 29, the voltage amplifier 30, and the difference calculator 37 is the same as the method of driving the servo motor 8 by the servo controller 33. Controller 3
Only the description of 2 will be given.

[0007] In the servo controller 32, the encoder 4 detects the motor position of the servo motor 5 and outputs it as motor position information. The difference calculator 37 detects the motor speed from the motor position information detected by the encoder 4 and outputs the motor speed information. The subtracter 48 subtracts the motor position information detected by the encoder 4 from the position command 1 and outputs the result. The position controller 24 includes the subtractor 4
8 is multiplied by the position gain to calculate and output a speed command. The subtractor 49 subtracts the motor speed information obtained by the difference calculator 37 from the speed command calculated by the position controller 24 to obtain a speed deviation. Speed controller 28
Calculates a torque command by performing a speed loop process such as proportional and integral control on the speed deviation obtained by the subtractor 49. The subtracter 50 subtracts the current feedback value from the voltage amplifier 30 from the torque command from the speed controller 28. The current controller 29 performs a process of converting the value from the subtractor 50 into a current command. The voltage amplifier 30 calculates the voltage value of each phase from the current command from the current controller 29 to control the servomotor 5 and outputs a current feedback value to the subtractor 50.

The subtracter 51 obtains a difference between the motor position information in the servo controller 32 and the motor position information in the servo controller 33. The position correction gain multiplier 31 multiplies the output of the subtractor 51 by a position correction gain and outputs the result as a correction value. The adder 52 outputs a command signal obtained by adding a correction value from the position correction gain multiplier 31 to a speed command from the position controller 24 as a speed command to the servo controller 33.

In the conventional synchronous control device shown in FIG. 6, a speed command for the servo motor 5 which is position-compensated based on the position deviation between the servo motor 5 and the servo motor 8 is used as a speed command for the servo motor 8. As a result, synchronous control of the two servo motors 5 and 8 can be realized.

More specifically, if there is a difference between the positions of the servo motor 5 and the servo motor 8, the speed command to the servo controller 33 is corrected to a value that compensates for the difference. , 8 are synchronously controlled.

When an attempt is made to construct such a conventional synchronous control device, a two-way controller for controlling the servomotors 5 and 8 is used.
Not only the two servo controllers 32 and 33, but also the position correction gain multiplier 31,
A configuration such as an adder 52 and a subtractor 51 is required. Even when the above-described compensation calculation is not performed, it is necessary to input a speed command from the servo controller 32 to the servo controller 33. However, when the above-described compensation calculation is performed by the servo controller 32 on the servo motor 5, the servo motor 8 Further, a circuit for inputting the motor position to the servo controller 32 needs to be added. Conversely, when the servo controller 33 performs the compensation calculation, it is necessary to add a circuit for inputting the motor position of the servo motor 5 to the servo controller 33.

When the compensation data is created by performing calculations inside the servo controller, the payout timing can be taken into consideration during software debugging and adjustment is easy. However, when compensation data is created outside the servo controller. Is difficult to adjust. Therefore, when data is exchanged via a network between servo controllers, there is a problem that the timing of dispensing compensation data does not match well and the performance of synchronous control is degraded. Further, since the control by the servo controller 32 is a position control and the control by the servo controller 33 is a speed control, both the servo motors 5 and 8 are controlled in a steady state and a transient state as compared with a configuration in which both servo motors 5 and 8 are controlled by position control. There is also a problem that a positional deviation occurs. Further, when the ball screw 10 is used as the first axis and the ball screw 11 is used as the second axis, the interference between the two axes may cause a load disturbance to cause oscillation.

[0013]

The above-mentioned conventional synchronous control device has the following problems. (1) A circuit for performing position compensation is required in addition to the servo controller for controlling the servomotor. (2) There is a possibility of deterioration of synchronous control performance, occurrence of position deviation, oscillation and the like, and stable control cannot be realized.

An object of the present invention is to provide a synchronous control device that can realize stable control without requiring a circuit other than a servo controller.

[0015]

To achieve the above object, a synchronous control device of the present invention controls the operation of one movable part by synchronously driving a plurality of servomotors based on the same position command. A synchronous controller provided for each of the plurality of servo motors, for controlling each servo motor based on an input position command, and a servo controller corresponding to the servo controller. And generating model torque information, model speed information, and model position information based on the position command. The difference between the generated model torque information and the motor torque information in the correspondingly provided servo controller is fixed. The signal subjected to phase compensation by multiplying the gain is fed back to the torque command in the servo controller, the generated model speed information and A signal obtained by multiplying a difference between the motor speed information in the corresponding servo controller by a certain gain and performing phase compensation is fed back to a speed command in the servo controller to generate the model position information. And a motor control device model for adding a signal obtained by multiplying a difference between the difference from the motor position information in the servo controller and a constant gain to the position command input to the servo controller.

According to the present invention, disturbance suppression can be performed by operating the servo controller according to the model of the corresponding motor control device. Therefore, an oscillation state can be prevented, and stable control can be realized.

Further, according to the present invention, since the interference between the two axes is regarded as a disturbance of each axis and the disturbance is suppressed, each of the independent axes is not corrected without performing the position correction between the two axes. Even when control is performed, synchronous control can be realized. Therefore, a synchronous control device can be easily realized only by combining a plurality of servo controllers for one axis without requiring a circuit for performing position compensation other than the servo controller.

Also, a first subtractor for subtracting model position information from the input position command and outputting the motor control device model is provided. The output from the first subtractor is multiplied by a position gain. Multiplier for outputting the model speed command from the model multiplier, a second subtractor for subtracting the model speed information from the model speed command from the model multiplier and outputting the same, and integrating the output from the second subtractor. And multiplying the model torque information from the first model integrator by a transfer function representing a servomotor, a load, and a speed gain. And a model obtained by performing an integral operation on the model speed information from the model speed control unit. A second model integrator for outputting the position information, and a third model for subtracting the motor position information of the servomotor controlled by the corresponding servo controller from the model position information from the second model integrator and outputting the result. A first subtractor which outputs a signal obtained by multiplying the output of the third subtractor by a constant gain to the position command input to the corresponding servo controller;
A fourth subtractor for subtracting the motor speed information from the corresponding servo controller from the model speed information from the model speed control unit and outputting the subtracted result; and a constant gain for the output of the fourth subtractor. And a second multiplier that outputs a signal obtained by multiplying the signal as a signal for feedback to a speed command in the corresponding servo controller, and motor torque information from the corresponding servo controller based on model torque information from the model integrator. A fifth subtractor for subtracting and outputting a signal, and a third multiplication for outputting a signal obtained by multiplying the output of the fifth subtracter by a constant gain as a signal for feeding back a torque command in a corresponding servo controller. And a container.

Further, the servo controller is controlled by a difference calculator for detecting the motor speed from the motor position information of the servo motor controlling the motor and outputting the detected motor speed as motor speed information, and the input position command. A first arithmetic unit that subtracts the motor position information of the servo motor that is present, adds the output from the first multiplier in the corresponding motor control device model and outputs the result, and an output from the first arithmetic unit. A fourth multiplier for multiplying by a position gain and outputting as a speed command, and subtracting the motor speed information output from the difference calculator from the speed command output from the fourth multiplier, and A second arithmetic unit for adding and outputting the output from the second multiplier in the motor control device model, and integrating the output from the second arithmetic unit. An integrator for outputting the obtained torque command, and subtracting the motor speed information output from the difference calculator from the torque command output from the integrator, and performing a third multiplication in a corresponding motor control device model. A third computing unit for adding the output from the motor and outputting the result as motor torque information; and multiplying the motor torque information output from the third computing unit by a speed gain to control the servomotor. A fifth multiplier generating a voltage may be used.

[0020]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a synchronization control device according to an embodiment of the present invention. In FIG. 1, the same components as those in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted.

The synchronous control device according to the present embodiment includes servo controllers 3 and 7 provided corresponding to the servo motors 5 and 8, and motor control devices provided corresponding to the servo controllers 3 and 7, respectively. Device model 2,
6, encoders 4, 9 and ball screws 10, 11,
And a table 12.

In the synchronous control device according to the present embodiment, FIG.
As in the conventional synchronous control device shown in FIG.
By controlling the movement of the table 12, which is a movable portion, by synchronously rotating the table 12 in the respective predetermined directions.

In the synchronous control device according to the present embodiment, a control system including a motor control device model 2, a servo controller 3, a servo motor 5, an encoder 4, and a ball screw 10;
Since the control system including the motor control device model 6, the servo controller 7, the servo motor 8, the encoder 9, and the ball screw 11 has the completely same configuration, only the configuration and operation of the control system for one axis will be described. . FIG. 2 shows a configuration of a motor control device model 2 and a servo controller 3 which are control systems for one axis.

The encoder 4 detects the position of the motor 5 and outputs information on the detected motor position to the motor controller model 2 and the servo controller 3.

The motor device model 2 is a model of a servo controller, and based on a position command 1,
Model torque information, model speed information, and model position information were generated, and the phase difference was compensated by multiplying the difference between the generated model torque information and the corresponding motor torque information in the servo controller 3 by a constant gain. The signal is fed back to the torque command in the servo controller 3, and a signal obtained by multiplying a difference between the generated model speed information and the corresponding motor speed information in the servo controller 3 by a constant gain to obtain a phase compensation signal The position command input to the servo controller 3 is obtained by multiplying the difference between the generated model position information and the corresponding motor position information of the corresponding servo controller 3 by a constant gain. The processing of adding to 1 is performed.

A specific configuration of the motor control device model 2 that performs such an operation will be described with reference to FIG. As shown in FIG. 2, the motor control device model 2 includes a switch 13, a model multiplier 14, a model integrator 15, a model speed control unit 16, a model integrator 17, a phase lead / lag filter 18, 20, 22 and multipliers 19, 21,
23 and subtractors 40 to 44.

The switch 13 has a function of determining whether or not to output the position command 1 to the subtractor 40. The on / off of the switch 13 determines the validity / invalidity of the function according to the present embodiment.

The subtracter 40 subtracts the model position information from the model integrator 17 from the position command 1 input via the switch 13 and outputs the result to the model multiplier 14. The model multiplier 14 adds the position gain Kp to the output from the subtractor 40.
Is multiplied and output as a model speed command. Subtractor 41
Subtracts the model speed information from the model speed controller 16 from the model speed command from the model multiplier 14 and outputs the result to the model integrator 15. The model integrator 15 outputs model torque information obtained by integrating the output from the subtractor 41.

The model speed controller 16 controls the model integrator 1
5, the model speed information obtained by multiplying the model torque information from No. 5 by a transfer function Kv / (s + Kv) representing the servo motor, load and speed gain is output. The model integrator 17 outputs to the subtractor 42 model position information obtained by performing an integration operation on the model speed information from the model speed controller 16.

The subtracter 42 is motor position information of the servo motor 5 controlled by the corresponding servo controller 3 based on the model position information from the model integrator 17.
The motor position information detected by the encoder 4 is subtracted and output to the phase lead / lag filter 18. Multiplier 1
9 is input through the phase lead / lag filter 18,
The difference between the model position information and the motor position information is multiplied by a gain α. The output of the multiplier 19 is added to the position command 1 input to the servo controller 3.

The subtracter 43 subtracts the motor speed information from the servo controller 3 from the model speed information from the model speed controller 16 and outputs the result to the phase lead / lag filter 20. The multiplier 21 includes a phase lead / lag filter 20
Is multiplied by the gain β between the difference between the model speed information and the motor speed information input through the. The output of the multiplier 21 is added to a speed command output from the multiplier 24.

The subtractor 44 subtracts the motor torque information from the servo controller 3 from the model torque information from the model integrator 15 and outputs the result to the phase lead / lag filter 22. The multiplier 23 includes a phase lead / lag filter 22
Is multiplied by the gain γ, the difference between the model torque information and the motor torque information input via the. The output of the multiplier 23 is added to the torque command output from the integrator 25.

The servo controller 3 includes a multiplier 2
4 to 26, a difference calculator 27, and calculators 45 to 47.

The difference calculator 27 detects the motor speed from the motor position information detected by the encoder 4 and outputs it as motor speed information. The arithmetic unit 45 calculates the position command 1
, The motor position information detected by the encoder 4 is subtracted, and the output from the multiplier 19 in the motor control device model 2 is added and input to the multiplier 24.

The multiplier 24 multiplies the output from the calculator 45 by the position gain Kp and outputs the result as a speed command. The arithmetic unit 46 subtracts the motor speed information output from the difference arithmetic unit 27 from the speed command output from the multiplier 24 and adds the output from the multiplier 21 to add the integrator 25.
To enter.

The integrator 25 outputs to the computing unit 47 a torque command obtained by integrating the output from the computing unit 46. The calculator 47 subtracts the motor speed information output from the difference calculator 27 from the torque command output from the integrator 25 and adds the output from the multiplier 23 to the multiplier 26 as motor torque information. You are typing. The multiplier 26 generates a torque command for controlling the servo motor 5 by multiplying the motor torque information output from the calculator 47 by a speed gain Kv.

Next, FIG. 3, FIG. 4, and FIG. 5 show the results of simulation using the synchronization control device of the present embodiment and the conventional synchronization control device.

FIG. 3 shows that one table 1 is driven by driving ball screws 10 and 11 by two servo motors 5 and 8.
FIG. 6 is a diagram showing a simulation model simulating controlling the operation of FIG. The numbers in FIG. 3 correspond to the numbers in FIG. 1, and the servo motors 5, 8, the ball screw 10,
11 and the models in Table 12 are represented by transfer functions. The transfer functions representing the models of the ball screws 10 and 11 include the spring characteristics of the ball screws. The servo motor 5, the ball screw 10, the table 12 and the motor 8, the ball screw 11, the table 1
2 is a two inertia model. When the resonance frequencies are different, vibration occurs in the conventional synchronous control device. A simulation was performed in which the integrated speed command at a feed speed of 60 m / min was used as position command data.

FIG. 4 shows a simulation result using the conventional synchronization control device, and FIG. 5 shows a simulation result using the synchronization control device of the present embodiment.

FIGS. 4 (a) and 5 (a) show speed response waveforms, and FIGS. 4 (b) and 5 (b) show torque response differences between the two shafts. 4 (c) and FIG. 5 (c)
FIG. 4D and FIG. 5D show the difference in speed response between the axes, and FIG. 4D shows the difference in position between the two axes.

As shown in FIG. 4, the conventional synchronous control device oscillates, but in the synchronous control device of the present embodiment, referring to FIG. 5, the torque difference (FIG. 5B) and the speed difference (FIG. 5 (c)), the peak value of the pulse deviation (FIG. 5 (d)) is about 1/10 to 1/100 as compared with FIG. 4, indicating that the vibration is suppressed.

Here, the torque difference, the speed difference, and the pulse deviation are obtained by taking the difference between the torque, the motor speed, and the pulse in the servo controller 3 and the servo controller 7, respectively.

Next, the reason why oscillation is suppressed according to the synchronous control device of the present embodiment will be described below.

In the conventional synchronous control device, since there is interference between the two axes, there is a problem that a synchronization error increases when high-speed feeding is performed, and when the dynamic characteristics of the two axes do not match, as shown in FIG. However, there is a problem that an oscillation state occurs. On the other hand, in the synchronous control device of the present embodiment, the servo controllers 3 and 7 are operated in the motor control device models 2 and 6 types. Then, the motor control device models 2 and 6
Does not include an element that oscillates, and therefore cannot oscillate in a command system. In addition, motor control device model 2,
Since no load disturbance occurs in the motor 6, the disturbance can be suppressed by operating the servo controllers 3 and 7 in the motor control device models 2 and 6 respectively. Therefore, the oscillation state can be prevented.

In the synchronous control device according to the present embodiment, 2
Since the interference between axes is regarded as disturbance of each axis and this disturbance is suppressed, synchronous control can be realized even if they are controlled independently without performing position correction between both axes. Can be. Therefore, according to the synchronous control device of the present embodiment, a control device including a motor control device model and a servo controller can be configured independently for each of the axes of the ball screws 10 and 11, so that one axis can be used. Can be easily replaced with a new controller for the synchronous control device. Further, since it is not necessary to extract a signal from one control device to the other control device, the number of signal lines is small, and the number of components for synchronous control is small. Also, since the parameters of the motor control device model are the same for both axes, there is an advantage that adjustment is required for one axis.

In the synchronous control device according to the present embodiment, the case where the drive of the table 12 as the movable portion is controlled by the two servo motors 5 and 8 has been described. However, the present invention is not limited to this. The present invention can be similarly applied to a case where the movable portion is synchronously driven by three or more servomotors.

[0048]

As described above, according to the present invention,
The following effects can be obtained. (1) Synchronous control of a plurality of servomotors can be performed without requiring a circuit for performing position compensation other than the servo controller. (2) Synchronous control that is illegal and stable, such as deterioration of synchronous control performance, occurrence of position deviation, occurrence of oscillation state, etc., can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a synchronization control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a motor control device model 2 and a servo controller 3, which are control systems for one axis in the synchronous control device shown in FIG.

FIG. 3 is a diagram showing a simulation model that simulates controlling the operation of one table 12 by driving ball screws 10 and 11 by two servo motors 5 and 8;

FIG. 4 is a diagram showing a simulation result using a conventional synchronization control device.

FIG. 5 is a diagram showing a simulation result using the synchronization control device of the present embodiment.

FIG. 6 is a block diagram showing a configuration of a conventional synchronization control device.

[Explanation of symbols]

1 Position command 2 Motor controller model 3 Servo controller 4 Encoder (E) 5 Motor (M) 6 Motor controller model 7 Servo controller 8 Motor (M) 9 Encoder (E) 10, 11 Ball screw 12 tables 13 switches 14 Model multiplier 15 Model Integrator 16 Model speed controller 17 Model Integrator 18 Phase lead / lag filter 19 Multiplier (α) 20 Phase lead / lag filter 21 Multiplier (β) 22 Phase lead / lag filter 23 Multiplier (γ) 24 Multiplier (Kp) 25 Integrator 26 Multiplier (Kv) 27 Difference calculator 28 Speed controller 29 Current controller 30 Voltage amplifier 31 Position correction gain multiplier 32, 33 Servo controller 34 Speed controller 35 Current controller 36 Voltage amplifier 37, 38 Difference calculator 40-44 subtractor 45-47 arithmetic unit 48-51 subtractor 52 adder 53, 54 Subtractor

Claims (3)

[Claims] 1. A synchronous control device for synchronously driving a plurality of servomotors based on the same position command to control the operation of one movable portion, wherein the synchronous control device corresponds to each of the plurality of servomotors. Provided,
A servo controller that controls each servo motor based on the input position command, and provided corresponding to the servo controller, based on the position command, model torque information, model speed information,
A signal obtained by generating model position information and multiplying a difference between the generated model torque information and the corresponding motor torque information in the servo controller provided by a certain gain to perform phase compensation is used as a torque command in the servo controller. And a signal obtained by multiplying a difference between the generated model speed information and the corresponding motor speed information of the servo controller by a constant gain and performing phase compensation to a speed command in the servo controller. A motor control device for adding a signal obtained by multiplying a difference between the generated model position information and the motor position information in the corresponding servo controller by a constant gain to the position command input to the servo controller; A synchronous control device comprising a model; 2. A motor control device model comprising: a first subtracter for subtracting model position information from the input position command and outputting the result; and a position gain multiplied by an output from the first subtractor. Multiplier for outputting the model speed command from the model multiplier, a second subtractor for subtracting the model speed information from the model speed command from the model multiplier and outputting the same, and integrating the output from the second subtractor. Multiplying a model torque information from the first model integrator by a transfer function representing a servo motor, a load, and a speed gain. A model speed control unit that outputs the model speed information obtained by the above, and a model position obtained by performing an integral operation on the model speed information from the model speed control unit. A second model integrator for outputting position information; and a third model for subtracting motor position information of a servomotor controlled by a corresponding servo controller from model position information from the second model integrator and outputting the result. A subtractor; a first multiplier that outputs a signal obtained by multiplying an output of the third subtractor by a constant gain as a signal for adding to the position command input to a corresponding servo controller; A fourth subtractor for subtracting and outputting the motor speed information from the corresponding servo controller from the model speed information from the model speed control unit, and a signal obtained by multiplying the output of the four subtracters by a constant gain, A second multiplier that outputs a signal for returning to a speed command in a corresponding servo controller, and a model multiplier that outputs a signal based on model torque information from the model integrator. A fifth subtractor for subtracting and outputting the motor torque information from the servo controller, and a signal obtained by multiplying the output of the fifth subtractor by a constant gain to a torque command in the corresponding servo controller. 3. The synchronous control device according to claim 1, further comprising a third multiplier that outputs the signal as a signal. 3. The servo controller according to claim 1, wherein the servo controller detects a motor speed from the motor position information of the servo motor controlling the motor, outputs the motor speed as motor speed information, and performs control based on the input position command. A first arithmetic unit that subtracts the motor position information of the servo motor that is present, adds the output from the first multiplier in the corresponding motor control device model and outputs the result, and an output from the first arithmetic unit. A fourth multiplier for multiplying by a position gain and outputting as a speed command, and subtracting the motor speed information output from the difference calculator from the speed command output from the fourth multiplier, and A second arithmetic unit for adding and outputting the output from the second multiplier in the motor control device model; and integrating the output from the second arithmetic unit. An integrator that outputs a corrected torque command; and a third multiplier in a corresponding motor control device model, wherein the motor speed information output from the difference calculator is subtracted from the torque command output from the integrator. A third computing unit for adding the output from the third computing unit to output as motor torque information; and a voltage for controlling the servo motor by multiplying the motor torque information outputted from the third computing unit by a speed gain. 3. The synchronization control device according to claim 2, further comprising: a fifth multiplier that generates the following.