JPH05313721A - Numerical controller - Google Patents

Abstract

PURPOSE:To provide the numerical controller capable of making the position of a motor and contents of a present position register coincide with each other in whiechever state the motor is made to be in a free state. CONSTITUTION:When a command pulse signal is outputted and a motor 50 is rotated and the motor 50 is made to be in a free state by an emergency stop switch 226 in this state, while the motor is kept stopped by an auxiliary computer, contents of a presetnt position register 216 is made to coincide with the position of the motor to cause both of them to coincide with each other. If the command pulse signal is not outputted from an acceleration calculating part 214 and the motor 50 is stopped at the time when the motor 50 is made to be in the free state by a speed control circuit 224, the motor 50 is operated in accordance with contents of a deviation counter 218 by the auxiliary computer, and contents of the present position register 216 and the position of the motor 50 are caused to coincide with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerical controller, and more particularly to position control of a motor for moving a moving member.

[0002]

2. Description of the Related Art A numerical control device is a device for moving a moving member to a command position commanded by numerical data, and is used in a machine tool, a welding device, an industrial robot, a carrier device, an industrial sewing machine and the like.

In a numerical control device, feedback control is generally performed to move a moving member to a command position. Therefore, a movement command means, a command pulse signal generating means, a deviation counter, a speed control circuit and an operation amount detector are provided. The movement command means issues a movement command including a target position value that is a numerical value representing the target position of the moving member, and the command pulse signal creation means creates a command pulse signal based on the target position value commanded by the movement command means. , Output to the deviation counter. The deviation counter stores the difference between the pulse number of the command pulse signal output from the command pulse signal creating means and the pulse number of the feedback pulse signal from the operation amount detector that detects the operation amount of the motor, and the speed control circuit The motor is driven while the speed is controlled by the analog voltage according to the content of the deviation counter. Thereby, the moving member is moved to the position designated by the target position value by the movement command means.

In such a numerical controller, conventionally, in order to start and stop the moving member with less impact, the motor is gradually accelerated, operated at a constant speed, and gradually decelerated. .. In this case, a distribution means is provided, and the operation amount increment for operating the motor is calculated and output from the target position value and the movement speed value issued by the movement command means at regular time intervals, and at the same time, the current position is calculated. A register is provided to store the current position value representing the current position of the motor and to update the contents by the operation amount increment value every time the operation amount increment value is output by the distributing means. Further, the command pulse signal creating means is designed to create and output a command pulse signal for accelerating, operating at a constant speed and decelerating the motor based on the operation amount increment value output from the distributing means. It In this way, the moving member starts to move gently and stops gently.

Further, in such a numerical control device, the speed control circuit is capable of switching the motor between the locked state and the free state, and free control means and emergency stop means for controlling the switching are provided. There is. The locked state is a state in which the motor is driven according to the content of the deviation counter, and the free state is a state in which the motor can freely rotate regardless of the content of the deviation counter.
The free control means is configured to cause the speed control circuit to put the motor in a free state in the state where the command pulse signal is not output, and the emergency stop means is configured to make the speed control circuit in the state where the command pulse signal is output. By making the motor in the free state, the motor is stopped and the output of the command pulse signal to the command pulse signal creating means is stopped.

The speed control circuit is configured to switch the motor between the locked state and the free state as described above for various reasons. For example, the speed control circuit of the motor for driving the work table of the 0 ° / 180 ° rotary work table device provided in the NC tapping machine is configured to switch the motor between the locked state and the free state for the following reason.

The work table of this device has a rectangular shape,
Workpieces are fixed to pallets respectively provided at both ends thereof, and the worktable is rotated to 0 ° and 180 ° so that one of the two is positioned at the processing position and the other is attached / detached for attaching / detaching the work. Be positioned in position. The work table device is provided with a clamp device that clamps the work table to the housing so that the work table does not move even if a large force is applied when the work is attached or detached, and the work being processed is not displaced. Has been

If the motor is locked while the work table is clamped in this way, and if the motor position shifts due to an external force including the clamping force, etc., a command pulse signal is not issued, but an operation amount is generated. The count value of the deviation counter changes based on the feedback pulse signal from the detector, and the speed control circuit operates the motor to try to cancel the change. However, when the external force is stronger, the motor cannot return to the original position, the speed control circuit tries to operate the motor with a larger voltage, and the position control is interrupted due to the overload of the motor. Therefore, when the work table is clamped and it is not necessary to rotate the work table, the motor is set to the free state, feedback control is performed even if the motor moves, and overload is not performed, and the clamp is released. Sometimes it is locked.

As described above, when the motor is in the free state and is moved by the external force, the current position value of the motor indicated by the current position register and the actual position of the motor do not match. The current position register is updated by the operation amount increment value distributed by the distribution means, and the contents of the current position register and the actual position of the motor match when the motor operates by an amount corresponding to the operation amount increment value. Therefore, if the motor moves freely regardless of the command pulse signal, the contents of the current position register and the actual position of the motor will not match.

Therefore, as a follow-up means for matching them, conventionally, when the motor is changed from the free state to the locked state, the contents of the current position register are updated according to the position of the motor while the motor is stopped. Means and current position register follow-up means for actuating the position of the motor to a position that matches the contents of the current position register without updating the contents of the current position register are known. The current position register follow-up method was adopted.

[0011]

However, in the case of the current position register follow-up means, for example, when the motor is driven and the motor is brought into the free state by the emergency stop means while the work table is being rotated. , There was a problem that the motor position and the contents of the current position register could not be synchronized.

While the contents of the current position register are updated by the operation amount increment value output by the distributing means, the command pulse signal creating means creates a command pulse signal for accelerating and decelerating the motor, Output. Therefore, during acceleration, the number of pulses output at regular intervals is gradually increased, and the motor operation amount during this period is the motor operation amount indicated by the current position register (the operation speed value commanded from the beginning of operation). It corresponds to the amount of operation when operated at a constant speed). This deficiency is recovered when the motor is decelerated when it is decelerated, and as a result the motor operates by the commanded amount.However, if the motor is stopped before the scheduled deceleration is performed, The actuation amount is still below the commanded amount,
There is a deviation between the actual operating position of the motor and the position of the motor represented by the current position register.

Further, even when the motor is operating at a constant speed, the command pulse signal generating means is arranged to
Since a large number of command pulses are created and sequentially output to operate the motor, when the command pulses of the number corresponding to the operation amount increment value have just been output, the motor within the operation amount increment value and the corresponding time Is equal to the operating amount of
If the output of the command pulses and the operation of the motor are stopped while the output of the command pulses of the number corresponding to the operation amount increment value is not finished, the deviation occurs due to the unoutput.

The above-mentioned two kinds of deviations are deviations between the contents of the current position register and the operation amount of the motor actually commanded by the command pulse signal creating means, and the number of command pulses output by the command pulse signal creating means. Since there is no difference between the number of feedback pulses that represents the actual operation amount of the motor and the number of feedback pulses that represent the actual operation amount of the motor, the motor cannot be rotated by the stored contents of the deviation counter, and there is a discrepancy between the motor position and the contents of the current position register. It will still occur. An object of the present invention is to provide a numerical controller capable of matching the position of the motor with the contents of the current position register regardless of the free state of the motor.

[0015]

In order to solve the above-mentioned problems, the present invention, as shown in FIG. 1, includes the movement command means 1, the distribution means 2, the current position register 3, and the command pulse signal generating means 4 as shown in FIG. , A deviation counter 5, a speed control circuit 6, a free control means 7 and an emergency stop means 8, and a command pulse signal creating means 4 creates a command pulse signal for accelerating the motor, operating it at a constant speed, and decelerating it. In the numerical control device in which the speed control circuit 6 can switch the motor between the locked state and the free state, a command pulse signal is output when the motor is brought into the free state by the speed control circuit 6. Is being output, when the speed control circuit 6 locks the motor next time, the contents of the current position register 3 are updated according to the position of the motor while the motor is stopped. And over data follow-up means 9, when the motor is in a state in which the command pulse signal is not output when it is in the free state by the speed control circuit 6,
Next, when the speed control circuit 6 locks the motor, the current position register follow-up means 10 for operating the motor to a position matching the contents of the current position register 3 without updating the contents of the current position register 3 is provided. The purpose is to provide.

[0016]

Operation: When the command pulse signal is output and the motor is rotated by the emergency stop means 8 while the motor is rotating, the contents of the current position register 3 and the command pulse signal creation means 4 command The deviation from the position can be known from the state of the command pulse signal creating means 4, and the deviation between the command position of the command pulse signal creating means 4 and the actual position of the motor can be known from the content of the deviation counter 5. Therefore, the position of the motor when the motor is locked next can be known from the contents of the command pulse signal creating means 4 and the deviation counter 5,
By matching the contents of the current position register 3 with the position of the motor while the motor is stopped by the motor follow-up means 9, both can be matched. On the other hand, if the command pulse signal creating means 4 does not output the command pulse signal when the motor is brought into the free state by the speed control circuit 6 and the motor is stopped, the contents of the current position register 3 And the command position of the command pulse signal creating means 4 match, the motor is brought into the free state. Then, the command pulse signal creating means 4
Since the deviation between the command position of the current position and the actual position of the motor can be known from the content of the deviation counter 5, when the motor is locked next time, the current position register follow-up means 10
Thus, the motor is operated according to the content of the deviation counter 5, and the content of the current position register 3 and the position of the motor are matched.

[0017]

As described above, according to the present invention, the distributing means 2, the current position register 3, the command pulse signal generating means 4,
In the numerical controller provided with the deviation counter 5 and the like, the current position is not changed when the motor is brought into the free state from the locked state while the motor is stopped, or the free state is provided during the rotation. The contents of the register 3 and the position of the motor can be matched, and the movement control of the moving member thereafter can be performed without any trouble.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment in which the present invention is applied to an NC tapping machine will be described in detail below with reference to the drawings.

FIG. 2 shows an NC tapping machine equipped with a 0 ° / 180 ° rotating work table device 10 (hereinafter abbreviated as work table device 10). The work table device 10 is provided with a work table 12 which holds a work and rotates by 180 °. The NC tapping machine is for processing the work table device 10 and a workpiece on the work table 12. Processing equipment 14
It has and. A tool 16 such as a drill, a center drill, or a tap attached to the processing device 14 can be moved to any position in the three-dimensional space. This is the processing device 14
Has three parts movable in the X-axis direction (direction perpendicular to the plane of the drawing), the Y-axis direction (horizontal direction in the drawing), and the Z-axis direction (vertical direction in the drawing).

The movement in the X-axis direction is supported on the carriage 20 by moving the carriage 20 supported by the bed 18 by the X-axis direction drive motor 21 (see FIG. 9). By moving the column 26 by the Y-axis direction drive motor 24, Z
Axial movement is performed by a spindle head 28 supported by a column 26.
Are moved by the Z-axis direction drive motor 30. Further, the tool 16 is rotated by a spindle drive motor 32 attached to a spindle head 28,
Cut the work piece. If necessary, the work table 12 is also set to 1 by a motor built in the work table device 10.
Rotate 80 °. The carriage 20, the column 26, and the spindle head 28 are moving members that move linearly, the spindle that holds the tool 16 and that is rotated by the spindle drive motor 32, and the work table 12 that moves by rotation.

As shown in FIG. 3, the work table device 10 is provided.
The work table 12 has a rectangular shape, and pallets 36 and 38 are provided at both ends in the longitudinal direction. Grooves 40 and 42 for attaching the work piece directly or via a jig are cut in the pallets 36 and 38, respectively, and the work table 12 is rotated by 180 ° at the time of the work, so that the pallet 36, 38 are alternately positioned at the processing position below the processing device 14 and the attachment / detachment position separated from the processing device 14.

As shown in FIG. 4, the work table device 10
Has a table drive motor 50. This motor 5
The rotation of 0 is transmitted to the pinion 58 integrally formed at the tip of the rotary shaft by the engagement of the spur gear 52 mounted on the rotary shaft of the motor 50 and the spur gear 56 mounted on the rotary shaft 54. The rotation is caused by the engagement of the pinion 58 and the gear wheel 60 (see FIG. 3).
(See).

The material of the pinion 58 is SCM (chromium molybdenum steel) material, and the material of the large gear 60 is SCM material, both of which are finished by quenching and grinding. The offset amount of the pinion 58 is 72 mm which corresponds to 30% of the outer diameter of the large gear 60, and the large gear 60 can rotate the large gear 60 by this offset amount, but the large gear 60 can rotate the pinion 58. It cannot be configured.

In the staggered bevel gear mechanism 62 composed of the pinion 58 and the large gear 60, the rotation of the pinion 58 generates an axial force, so that the rotation shaft 54 is supported as shown in FIG. Is performed by tapered roller bearings 64 and 66 which can receive not only radial force but also axial force. The tapered roller bearings 64 and 66 are supported by a pinion bracket 72 fixed to a housing 68 with bolts 70. Both ends of the rotating shaft 54 are provided with pinion brackets 72 via tapered roller bearings 64 and 66.
Is supported by the two tapered roller bearings 64, 6
6 is fitted into the pinion bracket 72 until it abuts on its shoulder surfaces 74, 76, and the tapered roller bearing 64
The inner ring of is contacted with the pinion 58 via the spacer 78, and the inner ring of the tapered roller bearing 66 is contacted with the lock nut 80, thereby preventing the relative movement of the rotary shaft 54 and the pinion bracket 72 in the axial direction. It has been done. When the lock nut 80 is tightened with respect to the rotary shaft 54, the pinion 58 and the lock nut 80 approach each other,
The inner rings of the tapered roller bearings 64 and 66 are brought close to each other,
Since the pinion bracket 72 is sandwiched between the outer rings of the tapered roller bearings 64 and 66, they cannot be approached, and the tapered roller bearings 64 and 66 are preloaded.

The pinion 58 is supported in a state where the backlash with the large gear 60 can be adjusted. The backlash adjustment is performed by adjusting the position of the pinion 58 in the axial direction and the radial direction. The adjustment in the axial direction is performed by the spacer 78 described above.
The radial adjustment is performed by adjusting the thickness of the
The bolt 82 shown in FIG. 6 shows a cross section along the cutting plane including the rotation axis of the work table 12 in the left half, and a cross section along the cutting plane including the rotation axis of the pinion 58 in the right half, and in the right half, the work table 12 is shown. It shows a state in which the rotating portion mainly composed of is removed. The clearance between the pinion bracket 72 and the housing 68 in the radial direction is adjusted by the bolt 82, and then the pinion bracket 72 is fixed to the housing 68. After the backlash adjustment is completed, the pinion bracket 72 and the housing 6 are fixed by the pin 84 shown in FIG.
8 relative movement is prevented.

As shown in FIG. 7, the work table device 10 is provided with a rotating portion 88 composed of a large gear 60, a spindle 86 and a work table 12 which are fixed to each other, and this rotating portion 88 is a cross roller bearing. It is supported by the housing 68 via 90. The inner ring of the cross roller bearing 90 is fixed between the work table 12 and the large gear 60, and the outer ring is fixed to the housing 68. A cutout 92 is formed on the outer peripheral surface of the spindle 86, and an origin sensor 94 for detecting the cutout 92 is fixed to the housing 68. With these, it is detected that one pallet 36 of the work table 12 is at the processing position.

Since the work table device 10 has the irreversible rotation characteristic as described above, it does not need a clamp mechanism. However, in the work table device 10 of the present embodiment, while machining is performed on one of the pallets 36 and 38, the work piece is attached and detached on the other side, so that it is large when the work piece is attached and detached. A clamp device 96 is provided as shown in FIG. 7 for the purpose of preventing a slight positional deviation from occurring in the position of the workpiece being machined even if a force is applied.

The clamp device 96 is of a friction type in which the rotation of the rotary portion 88 is prevented by the frictional force between the clamp disk 98 attached to the spindle 86 and the housing 68. The clamp disk 98 is fixed to the lower end of the spindle 86 by a bolt 100 and a pin 102, and faces the friction surface 104 formed on the housing 68 with a minute gap. A clamp cylinder 106 is provided behind the clamp disk 98. The clamp cylinder 106 includes a cylinder housing 108 and a clamp piston 110 that is liquid-tightly fitted to the cylinder housing 108 and is axially movable. Clamp piston 110
Is always kept at the retracted position slightly apart from the clamp disc 98 by the return spring 112, but the clamp piston 110 and the cylinder housing 10 are
8 is moved forward by supplying hydraulic pressure to the hydraulic chamber 114 formed between the clamp disk 98 and the friction surface 10.
Press on 4.

The hydraulic chamber 114 is provided in the cylinder housing 10.
The liquid passage 116 and the pipe 118 formed at 8 are connected to the hydraulic pressure source 120. An electromagnetic directional control valve 122 is provided in the pipe line 118 to connect the hydraulic pressure chamber 114 to the hydraulic pressure source 12
The hydraulic chamber 11 is adapted to be switched between a state in which it is in communication with 0 and a state in which it is in communication with the tank 124.
4 is communicated with the hydraulic pressure source 120. A pressure sensor 126 is provided in the pipeline 118, detects the hydraulic pressure in the hydraulic chamber 114, and outputs an ON signal when the hydraulic pressure in the hydraulic chamber 114 becomes lower than a set value and the clamp is released. When the work table 12 is clamped at a value higher than the set value, an OFF signal is issued.

The NC tapping machine is controlled by the main controller 130 shown in FIG. 8 and the sub controller 132 shown in FIG. These control devices 130 and 132 are shown in FIG.
It is attached to the bed 18 as shown in FIG. The main controller 130 includes a main CPU 134, a main ROM 136, and a main R.
Mainly comprises a main computer 141 having an AM 138 and a bus 140 connecting them.
A keyboard 144, an input device 146, an emergency stop switch 148, and the like are connected to 40 via an input / output unit 142.
Data and signals are provided.

The keyboard 144 is used for inputting an operation program, data, etc., and is provided with a large number of keys such as numeric keys and alphabet keys. The input device 146 is N
This is a device for inputting C data (operation program including numerical data), and the input is performed by reading NC data punched on a paper tape. The emergency stop switch 148 is operated to issue an ON signal when the operation of the machine needs to be stopped for some reason. However, it is the mechanical part of the machine that is stopped, and the power of the computer remains on.
A display device 152 and the like are also connected to the input / output unit 142 via the control circuit 150.

An operation data buffer 160 is further connected to the input / output unit 142, and an operation data memory 162 is connected to the operation data buffer 160. The operation data memory 162 stores various operation programs managed by program numbers. The operation program consists of a series of instruction codes, and a part of the instruction codes stored in the operation data memory 162 is continuously read and stored in the operation data buffer 160 in accordance with a request from the main CPU 134.

The sub-control device 132 is a device for controlling the motor, and like the main control device 130, mainly comprises a sub-computer 180 having a sub-CPU 170, a sub-ROM 172, a sub-RAM 174 and a bus 176 connecting them. is there. The drive circuits 182, 184, 186, 188, 19 are connected to the input / output unit 178 connected to the bus 176.
Drive motors 21, 24, 30, drive motors 21, 24, 30 in the X-axis, Y-axis, and Z-axis directions, a main shaft drive motor 32, a table drive motor 50, an electromagnetic directional control valve 122, etc. are connected via 0, 191, and Pulse encoders 192, 194, 196, 198, 200 for detecting the respective rotation amounts
Further, a pressure sensor 126 provided on the clamp device 96 of the work table device 10 is connected. The pulse encoders 192-200 are incremental encoders that generate one pulse each time the motor rotates by a certain angle. The detection signal of the pressure sensor 126 is also supplied to the main computer 141.

Main computer 141 and sub computer 1
A shared motor command memory 204 is provided between these computers 141 and 180 for exchanging information with each other. Motor command memory 20
4 is provided with a storage area for each of the five motors 30, 40, 52, 58, 82 controlled by the sub-control device 132, and the target position or movement amount or direction of the moving member moved by the motors is provided. Data for instructing etc. is stored. Further, each storage area is provided with a command execution start flag and a command execution end flag for instructing the start and end of the commanded operation.

FIG. 10 is a conceptual illustration of the main computer 141 and the sub computer 180, in which the parts for controlling the table drive motor 50 for rotating the work table 12 and the clamp device 96 in the work table device 10 are extracted and shown in FIG. is there. Among the constituent elements of FIG. 10, the NC control unit 210 and the current position register 216 are configured by the main computer 141, and the axis movement control unit 2
12, the acceleration / deceleration calculation unit 214 and the deviation counter 218 are configured by the sub computer 180. Also, D
The A converter 222 includes an input / output unit 178, and the speed control circuit 224 corresponds to the drive circuit 190.

The NC controller 210 uses the operation data buffer 1
The NC data transferred to 60 is read and analyzed, converted into internal data that can be executed by a computer, and if the NC data is a rotation command for the work table 12, the target movement position of the work table 12 The rotation command value including the rotation speed is output. Axis movement control unit 212
Calculates the rotation amount θ and the rotation speed ω of the motor 50 required to execute the rotation command from the target rotation position and rotation speed of the work table 12 and the contents of the current position register 216, and distributes them to obtain the current value. Position register 216
And the acceleration / deceleration calculation unit 214. The distribution is to obtain the number of distribution command pulses to be supplied to the deviation counter 218 within a certain time Δt in order to achieve the rotation amount θ at the rotation speed ω.

A more specific description will be given. In order to rotate the table drive motor 50 at the rotation speed ω by θ degrees, Δt
It is necessary to rotate by Δθ (= ω · Δt) degrees for each time, and the command pulse numbers corresponding to θ degrees and Δθ degrees are p (= kθ) and Δp (= kωΔ, respectively).
If it is t), it is decided by distribution to supply Δp command pulses every Δt time n (= p / Δp) times. Thereby, the content of the current position register 216 is updated by adding the value Δp distributed by the axis movement control unit 212, and the current position value of the table drive motor 50 represented by the current position register 216 is shown in FIG. It will be increased step by step.

Further, the acceleration / deceleration calculation unit 214 is supplied with the command pulse number kω per unit time and the distribution command pulse number Δp corresponding to the rotation speed ω. Acceleration / deceleration calculation unit 21
4 produces a command pulse signal in response to this and outputs it to the deviation counter 218, but at the beginning of rotation, the table drive motor 50 is accelerated by a predetermined time constant,
After rotating at a constant speed, a command pulse signal is created to decelerate and stop with the same time constant. That is, at the time of acceleration, a command pulse signal is created so that the pulse output time interval gradually narrows from a wide state and becomes the same as the transmission time interval Δt / Δp at constant speed rotation. The command pulse signal is generated so that

In this way, when the table drive motor 50 is accelerated, rotated at a constant speed, and decelerated, Δp command pulses are not output within Δt time during acceleration, and the number of command pulses is increased by the amount shown by hatching in FIG. The constant speed rotation is performed with the shortage of the shortage, but the shortage is compensated during deceleration. The deceleration is performed after the distribution of Δp pulses n times is completed, whereby the table drive motor 50 is rotated by the target rotation angle θ.

The deviation counter 218 is the acceleration / deceleration calculation unit 214.
1 is added each time one command pulse signal is supplied from the pulse encoder 200, and 1 is subtracted each time one feedback pulse is supplied from the pulse encoder 200 that detects the rotation amount of the table drive motor 50. The difference is stored, and the digital value of the difference is converted by the DA converter 222 into an acceleration / deceleration command voltage that is an analog amount and output to the speed control circuit 224.

The speed control circuit 224 is a circuit for driving the table drive motor 50 while changing the speed of the table drive motor 50 with a gradient corresponding to the acceleration / deceleration command voltage, and the table drive motor 50 is in a locked state and a free state. A switch 226 that can be switched to and is provided. The switch 226 is controlled by the axis movement control unit 212.

When the switch 226 is in the contact (ON) state, the table drive motor 50 is in a locked state controlled by the speed control circuit 224. The speed of the table drive motor 50 is controlled so that the content of the deviation counter 218 is maintained at an offset value that cancels the offsets of the DA converter 222 and the speed control circuit 224. Generally, the DA converter 222 and the speed control circuit 224 have an offset more or less, and if there is an offset, the table drive motor 50 operates at a constant speed (speed 0, speed 0, even if the output value of the deviation counter 218 is 0). In other words, including stop)
Can't be kept. Therefore, an offset value that can cancel this offset is set in advance in the deviation counter 218, and when it is necessary to keep the table drive motor 50 at a constant speed, the offset value is output from the deviation counter 218. -ing

It should be noted that this offset value is set after the table drive motor 50 is once turned off, as will be described later.
It is updated every time it is turned on, and the stop position of the table drive motor 50 is controlled with high accuracy despite the fluctuation of the offset of the DA converter 222 and the speed control circuit 226.

Further, when the switch 226 is in the disconnected (OFF) state, the table drive motor 50 is operated by the speed control circuit 224.
It is in the free state that is not controlled by. This switch 22
6 is turned on when the work table 12 is rotated, and is turned off when the work table 12 is rotated and positioned. When the work table 12 is clamped by the clamp device 96 and an external force is applied to the work table 12 and the position of the work table 12 is displaced, if the switch 226 is ON, feedback control is performed to try to return the work table 12 to the original position. However, when the external force is larger, the original position cannot be returned, and a larger current is supplied to the table drive motor 50 to cause an overload, so that it is not necessary to rotate the work table 12 to avoid it. Therefore, the switch 226 is turned off.

The switch 226 is turned off not only when the work table 12 is not rotated but also when the emergency stop switch 148 is turned on and an emergency stop is instructed. In this case, the switch 226 is turned off and the table drive motor 50 is brought into a free state regardless of whether the table drive motor 50 is rotating.

The sub ROM 172 of the sub computer 180 stores the work table rotation control routine shown in FIG. 11, the emergency stop processing routine shown in FIG. 12, and the emergency stop release processing routine shown in FIG. Hereinafter, the rotation control of the work table 12 and the control at the time of operating the emergency stop switch 148 will be described based on these routines.

In the work table rotation control routine, first, in step S1 (hereinafter abbreviated as S1; the same applies to other steps), it is determined whether or not a work table rotation command is issued. When the instruction code read from the operation data buffer 160 is the rotational positioning of the work table 12, the main computer 141 functioning as the NC control unit 210.
Stores the rotation direction, the target rotation position, the rotation speed, etc. of the work table 12 in the motor command memory 204 and sets the command execution start flag. Therefore, whether or not the command execution start flag is set is determined. It is determined whether or not.

If the determination result is YES, S2
After the switch 226 of the speed control circuit 224 is turned on in S, S3 is executed and the clamp of the work table 12 is released. When the clamp release signal is turned on, the electromagnetic direction switching valve 122 of the clamp device 96 is switched, the hydraulic chamber 114 is communicated with the tank 124, and the clamp is released. When the clamp is released, the signal of the pressure sensor 126 is turned on, and the next step is executed accordingly. It should be noted that ON / OFF of the clamp release signal, ON / OFF of the clamp release confirmation signal generated by the pressure sensor 126, ON / OFF of the switch 226 of the speed control circuit 224, and the table drive motor 50.
The timing of executing the rotation control (rotational positioning of the work table 12) is shown in the time chart of FIG.

Next, S4 is executed, and the deviation counter 218
The average value of the offset values of is acquired. DA converter 22
2 and the offset of the speed control circuit 224 usually fluctuate, and also change due to temperature change during long-term use, so that the rotation control of the table drive motor 50 is performed before starting the rotation control. Deviation counter 218
The average value of the values is calculated and the offset value is updated.

Following the update of the offset value, S5 is executed to position the work table 12. The target rotation position, rotation speed and rotation direction of the table drive motor 50 are read from the motor command memory 204, distributed by the function of the axis movement control unit 212 of the sub computer 180, and output to the current position register 216. At the same time, the function as the acceleration / deceleration calculation unit 214 creates a command pulse signal, and the deviation counter 2
18 and the command execution end flag of the motor command memory 204 is reset.

The deviation counter 218 outputs the difference between the pulse number of the command pulse signal and the feedback pulse number, and the speed control circuit 224 controls the speed of the table drive motor 50 with an analog voltage according to the contents of the deviation counter 218. To drive. As described above, the acceleration / deceleration calculation unit 214 creates the command pulse signal so that the table drive motor 50 is first accelerated, then rotated at a constant speed, and then decelerated when stopped. Starts rotating gently and then stops. When the table drive motor 50 rotates by the commanded amount and the positioning of the work table 12 is completed, the command execution end flag of the motor command memory 204 is set.

After the positioning, the work table 12 is clamped. When the clamp release signal is turned off, the electromagnetic directional control valve 122 is switched, and the hydraulic chamber 1
Since 14 is connected to the hydraulic pressure source 120 to supply hydraulic pressure, if the signal of the pressure sensor 126 is turned off and the clamp is completed, S7 is executed and the speed control circuit 224 is executed.
The switch 226 is turned off. Then, in S8, the state of the table drive motor 50 and the deviation counter 2
The contents of 18 are stored in the sub RAM 174, and the execution of the routine ends. The state of the table drive motor 50 indicates whether the table drive motor 50 is rotating or is stopped. Since the command execution end flag of the motor command memory 204 is set when S8 is executed, it is determined that the table drive motor 50 is stopped. Information is stored. In addition, the signal of the pressure sensor 126 is OFF
In response to this, the main computer 141 resets the command execution start flag of the motor command memory 204.

Next, the case where the emergency stop switch 148 is operated will be described. An interrupt signal is issued in response to the operation of the emergency stop switch 148, the execution of the work table rotation control routine of FIG. 11 is stopped, and
The emergency stop processing routine shown in 2 is executed. First,
In S101, the switch 226 of the speed control circuit 224
After is turned off, it is determined in S102 whether or not the state of the table drive motor 50 and the content of the deviation counter 218 are stored.

When the rotation positioning of the work table 12 is completed and the emergency stop is instructed after the command execution completion flag is set, the determination result of S102 is YES and the routine execution is completed. Table drive motor 5
The state of 0 and the contents of the deviation counter are maintained as they are stored in S8. On the other hand, when the work table 12 is rotating, the command execution start flag is set, and the command execution end flag is not yet set, the determination result of S102 is NO and S103 is executed. , The state of the table drive motor 50 and the contents of the deviation counter 218 are sub RAMs.
It is stored in 174.

The portion functioning as the acceleration / deceleration calculation unit 214 of the sub computer 180 counts the total number of command pulse signals output to the deviation counter 218, and when the emergency stop is instructed, the pulse signal generation, The output is stopped and the total number of pulses stops at the value at the time of stop.

The switch 22 of the speed control circuit 224
6 is turned off, the table drive motor 5
0 becomes a free state, and after a small amount of rotation due to inertia, it stops. This amount of rotation is detected by the pulse encoder 200, fed back to the deviation counter 218, and stored.

Then, if the emergency stop is released, FIG.
The emergency stop release processing routine shown in 3 is executed, and S2
01, the switch 226 of the speed control circuit 224 is turned off.
When it is set to FF, it is determined whether or not the table drive motor 50 is rotating. S2 if not rotating
The determination result of 01 is NO, and the execution of the routine ends.

Therefore, when the switch 226 is turned on next in response to the work table rotation command, the contents of the current position register 216 remain unchanged and the table drive motor 50 is rotated in the reverse direction by the amount of rotation in the free state. It is returned to the position before being freed. The current position register follow-up is performed to match the position of the table drive motor 50 with the contents of the current position register 216.

Table drive motor 5 in free state
The rotation amount of 0 is stored in the deviation counter 218, and the speed control circuit 226 rotates the table drive motor 50 in the reverse direction so as to cancel the stored rotation amount, thereby causing the current position register 216 to rotate. The target position and the actual position of the table drive motor 50 represented by the current position value of are matched. If the table drive motor 50 is not rotating when the switch 226 is turned off by the instruction of the emergency stop, the contents of the current position register 216 and the command position of the sub computer 180 functioning as the acceleration / deceleration calculation unit 214 are combined. If the table drive motor 50 is rotated according to the stored contents of the deviation counter 218, the rotation of the table drive motor 50 after the emergency stop is returned to the original position register 2
The position of the table drive motor 50 is matched with the contents of 16.

On the other hand, when the switch 226 of the speed control circuit 224 is turned off, the table drive motor 5
If 0 is rotating, the determination result of S201 is YE.
When S is reached and S202 is executed, the current position register 21
A motor follow-up is executed to match the contents of 6 with the actual position of the table drive motor 50. This motor follow-up is performed as follows.

Acceleration / deceleration calculator 21 of the sub computer 180
In the portion functioning as 4, the total number of command pulse signals transmitted at the time when the emergency stop is instructed is stored, the command position of the table drive motor 50 at that time is known, and in the deviation counter 218, The amount of deviation between the command position when the emergency stop is instructed and the actual position of the table drive motor 50 is stored and is updated by the amount of rotation while the table drive motor 50 is in the free state. Therefore, the current position of the table drive motor 50 is known from the contents of the deviation counter 218 and the total transmission number of the command pulse signals stored in the portion functioning as the acceleration / deceleration calculation unit 214 of the sub computer 180, and the current position is found at this position. The contents of the position register 216 are matched.

The case where the emergency stop is instructed while the table drive motor 50 is rotating at a constant speed will be described more specifically by taking an example. When the table drive motor 50 is accelerated, the number of command pulses supplied to the deviation counter 218 is smaller than that at the constant speed rotation as described above, and the current position register 21 is used.
While the contents of 6 are increased at once by the number of distribution command pulses at one time, the command pulses to the deviation counter are supplied every moment, so if an emergency stop is performed at the time shown in FIG. At that time, the command position to the deviation counter 218 is p with respect to the contents of the current position register 216.
_A (called command shortage) is insufficient.

Further, the table drive motor 5 at the time of emergency stop
There may be a difference between the actual position of 0 and the command position to the deviation counter 218, and the table drive motor 50 may rotate a small amount due to inertia or external force even after the emergency stop. Also between the command position to 218 and the actual position of the table drive motor 50, p _B (referred to as the deviation amount from the command) occurs.

Therefore, if an emergency stop is performed while the table drive motor 50 is rotating at a constant speed, a command shortage amount p _A between the contents of the current position register 216 and the actual position of the table drive motor 50 is set. And deviation from command p _B
It will be that there is equal displacement to the difference between, the shift amount p _A
By subtracting -p _B from the current position value of the current position register 216, the contents of the current position register 216 can be matched with the actual position of the table drive motor 50.

As described above, in the present embodiment, when the table drive motor 50 is brought into the free state by performing the emergency stop during the rotation of the table drive motor 50, the motor follow-up and the work table 12 are performed. When the table drive motor 50 is brought into a free state at the end of positioning of the table drive motor or an emergency stop is performed while the table drive motor 50 is stopped, the contents of the current position register 216 and the contents of the current position register 216 are determined by follow-up of the current position register. The actual position of the table drive motor 50 is matched. Therefore, the subsequent positioning of the work table can be performed without any trouble.

As is apparent from the above description, in this embodiment, the NC control unit 210 of the main computer 141 is used.
The portion functioning as is the operation data memory 162, the operation data buffer 160, and the motor command memory 204.
And the movement command means 1 are configured in cooperation with the above. The portion of the sub computer 180 that functions as the axis movement control unit 212 constitutes the distribution unit 2, and the portion that functions as the acceleration / deceleration calculation unit 214 constitutes the command pulse signal generation unit 4. Furthermore, the DA converter 22 of the sub computer 180
Input / output unit 178 functioning as 2, and speed control circuit 22
4 and a drive circuit 190 functioning as a switch 226.
And constitute the speed control circuit 6, the area for storing S7 of the sub ROM 172 and the portion of the sub CPU 170 for executing S7 constitute free control means 7, and the emergency stop switch 14
8, the area for storing S101 of the sub ROM 172 and the portion of the sub CPU 170 for executing S101 constitute the emergency stop means 8. In addition, S103 of the sub ROM 172,
The portion that stores S202 and the portion that executes those steps of the sub CPU 170 are the motor follow-up means 9.
The area for storing S8 and S201 of the sub ROM 172 and the portion of the sub CPU 170 for executing these steps are the current position register follow-up means 10.
Are configured.

The present invention controls the motors other than the table drive motor for driving the work table of the work table device in the NC tapping machine, machine tools other than the NC tapping machine, transfer devices, industrial robots, welding devices, etc. It can also be applied to the numerical control device.

Besides, the present invention can be carried out in various modified and improved modes based on the knowledge of those skilled in the art without departing from the scope of the claims.

[Brief description of drawings]

FIG. 1 is a diagram conceptually showing a configuration of the present invention.

FIG. 2 is a side view showing the appearance of an NC tapping machine that is an embodiment of the present invention.

FIG. 3 is a plan view showing a work table device of the NC tapping machine.

FIG. 4 is a plan view showing the work table detached from the work table device and partly in section.

5 is an enlarged plan sectional view showing a pinion and its peripheral portion in the work table device shown in FIG. 4. FIG.

6 is a cross-sectional view taken along the line AA ′ in FIG.

FIG. 7 is a side sectional view of the work table device.

FIG. 8 is a block diagram showing a main controller that controls the NC tapping machine.

FIG. 9 is a block diagram showing a sub control device for controlling the NC tapping machine.

FIG. 10 is a block diagram showing a part related to control of a table drive motor of the work table device taken out of a main computer and a sub computer which are main components of the main control device and the sub control device.

FIG. 11 is a flowchart showing a work table rotation control routine stored in a sub ROM of the sub computer.

FIG. 12 is a flowchart showing an emergency stop processing routine stored in the sub ROM.

FIG. 13 is a flowchart showing an emergency stop release time processing routine stored in the sub ROM.

FIG. 14 is a time chart of work table rotation control performed according to the work table rotation control routine.

FIG. 15 is a diagram illustrating motor follow-up performed in the processing routine at the time of releasing the emergency stop.

[Explanation of symbols]

 12 work table 20 carriage 21 X-axis direction drive motor 24 Y-axis direction drive motor 26 column 28 main spindle head 30 Z-axis direction drive motor 50 table drive motor 130 main controller 132 sub controller 141 main computer 180 sub computer

Claims (1)

[Claims] 1. A movement command means for issuing a movement command including a target position value and a movement speed value of a moving member which is moved by a motor, and from the target position value and the movement speed value at regular time intervals,
Distribution means for obtaining and outputting an operation amount increment value for operating the motor, and a current position value representing the current position of the motor are stored, and the operation is performed every time the operation amount increment value is output by the distribution means. A current position register whose contents are updated in increments of quantity, and a command pulse signal for accelerating, operating at a constant speed and decelerating the motor based on the increment of operation quantity output from the distributing means. And a command pulse signal generating means for outputting, and a deviation counter for storing the difference between the pulse number of the command pulse signal output and the pulse number of the feedback pulse signal from the operation amount detector for detecting the operation amount of the motor. And, the motor can be driven while controlling the speed with an analog voltage according to the content of the deviation counter, and the motor can be switched between the locked state and the free state. A speed control circuit, free control means for causing the speed control circuit to put the motor in a free state in a state in which the command pulse signal is not output, and in the state in which the command pulse signal is output, to the speed control circuit In a numerical control device including an emergency stop means for stopping the motor by causing the motor to be in a free state and stopping the output of the command pulse signal to the command pulse signal creating means, the motor is freed by the speed control circuit. When the command pulse signal is being output when the state is changed,
Next, when the speed control circuit locks the motor, the motor follow-up means for updating the contents of the current position register according to the position of the motor while the motor is stopped, and the motor is freed by the speed control circuit. If the command pulse signal is not output when the motor is put into the state, when the speed control circuit next locks the motor, the motor is not updated without updating the contents of the current position register. And a current position register follow-up means for operating up to a position that matches the contents of the current position register.