JP6013681B2 - Servo press machine - Google Patents

Description

  The present invention relates to a servo press device that is operated by a servo motor, and more particularly to a servo press device that includes a control device that is characterized by a method for controlling a servo motor.

In many factories that perform machining, a servo press device that operates by a servo motor (for example, Patent Document 1) is used. Here, the reasons why the servo press device is used in many factories include advantages such as no need for large equipment such as pneumatic equipment or hydraulic equipment, and high controllability of the press operation.

JP 2011-115835 A

  In the servo press apparatus as described above, the servo motor that operates the press mechanism of the press apparatus is generally controlled by current control. In this current control, a current command signal corresponding to the load detection signal from the load cell that detects the press load of the press mechanism is formed, and the drive of the servo motor is controlled based on this current command signal.

However, when controlling the servo motor by current control in this way, there is a concern that a predetermined current command signal may continue to be output due to an abnormality inside or outside the control device. When the predetermined current command signal continues to be output as described above, the servo press device continues to operate and safety is not guaranteed.

Accordingly, the present invention has been made in view of the above-described circumstances, and provides a servo press device that is guaranteed to operate safely.

In order to solve the above problems, a servo press device according to claim 1 is a servo motor including a motor shaft, a press mechanism operated by the servo motor, a load cell for detecting a press load of the press mechanism, a servo A rotation position sensor that detects the rotation position of the motor shaft of the motor, and a control device that supplies control power to the servomotor based on detection signals from the load cell and the rotation position sensor. In this servo press device, the control device includes a subtracter, a load controller, an adder, and a servo motor driver.

Here, the subtracter in the control device calculates a load deviation signal based on the load command signal and the load detection signal from the load cell. The load controller is a rotation control signal for rotating the motor shaft of the servo motor by a predetermined angle from the reciprocal of the load deviation signal and a predetermined position proportional gain in order to generate a press load corresponding to the load deviation signal. Is calculated. The adder calculates a rotational position command signal to rotate the motor shaft of the servo motor toward a predetermined rotational position based on the rotational control signal and the rotational position detection signal from the rotational position sensor. Then, the servo motor driver calculates control power using the position proportional gain to rotate the motor shaft of the servo motor to the rotational position corresponding to the rotational position command signal, and supplies it to the servo motor.

  Thus, the servo press apparatus described in claim 1 uses the rotational position command signal as a control signal to the servo motor driver that controls the control power supplied to the servo motor. Therefore, even when a predetermined rotational position command signal is continuously output due to an abnormality inside and outside the control device, the servomotor is safely stopped after the motor shaft of the servo motor is rotated to a predetermined rotational position. Therefore, the servo press device according to claim 1 is guaranteed to operate safely.

In the servo press device according to the first aspect, as described above, the rotational position command signal is used as a control signal to the servo motor driver. Here, the rotational position command signal is generated based on the rotational control signal smoothed in time by the load control device, and the rotational position command signal is also a signal smoothed in time. Accordingly, when the servo motor driver is operated by the control signal smoothed in this way, a stable control current is output from the servo motor driver without being messy. Therefore, the servo press device described in claim 1 can realize highly stable motor control.

  Next, the servo press apparatus according to claim 2 is the servo press apparatus according to claim 1, wherein the control device of the press apparatus includes an output filter.

Here, the output filter has a filter characteristic that compensates for the delay transmission characteristic of the press mechanism, and corrects the rotational position command signal based on the filter characteristic, and outputs the corrected corrected rotational position command signal. The servo motor driver of the control device supplies control power to the servo motor so as to rotate the motor shaft of the servo motor to the rotational position corresponding to the corrected rotational position command signal.

  Thus, the press apparatus described in claim 2 includes an output filter configured with a filter characteristic that compensates for a delay transmission characteristic of the press mechanism. The output filter corrects the rotational position command signal and outputs the corrected rotational position command signal to the servo motor driver. Thus, the servo motor driver can compensate for the above dynamic characteristics by outputting a command signal that can compensate for the dynamic characteristics (transmission characteristics) of the mechanical delay of the press mechanism to the servo motor driver. A control current can be supplied to the servo motor. Therefore, the press apparatus described in claim 2 can cancel the operation delay of the press mechanism that inevitably has a delay transmission characteristic, and becomes a highly responsive apparatus.

Next, a servo press device according to a third aspect is the servo press device according to the second aspect, wherein the filter characteristic of the output filter is a reverse transmission characteristic of a delay transmission characteristic of the press mechanism or the press mechanism. The delay transmission characteristic is a characteristic corresponding to the characteristic corresponding to the inverse transmission characteristic of the approximate delay transmission characteristic obtained by approximating the second delay system .

Thus, by configuring the filter characteristic of the output filter to correspond to the reverse transmission characteristic of the delay transmission characteristic of the press mechanism, it is possible to effectively cancel out the operating delay of the press mechanism that inevitably has the delay transmission characteristic. The press device having the output filter can be a highly responsive device. Also, by configuring the filter characteristics of the output filter to correspond to the reverse transmission characteristic of the delay transmission characteristic of the press mechanism, it is possible to effectively cancel out the operating delay of the press mechanism that inevitably has the delay transmission characteristic. The press device having the output filter is a highly responsive device.

Next, in a servo press device according to a fourth aspect of the present invention, a ball screw whose press mechanism is rotated by the servo motor, a screw nut screwed into the ball screw, and one end of the ball screw are rotatable. A base plate to be supported; a main shaft having one end fixed to the base plate; a first linear member that is integrally attached to the screw nut and linearly moves along the main shaft; and the first shaft of the main shaft. A second linear motion member disposed between the linear motion member and the base plate, wherein the first linear motion member is linearly moved by a rotation operation of the servo motor to generate a press load. To do.

ADVANTAGE OF THE INVENTION According to this invention, the servo press apparatus guaranteed to operate | move safely can be provided.

It is a model figure which shows the servo press apparatus of the 1st Embodiment of this invention. 1 is a system block diagram showing a servo press apparatus according to a first embodiment of the present invention. It is a system block diagram which shows the servo press apparatus of the 2nd Embodiment of this invention.

Next, a servo press device 1 according to a first embodiment of the present invention will be described with reference to FIGS. Here, FIG. 1 is a model diagram showing the servo press apparatus according to the first embodiment of the present invention, and FIG. 2 is a system block diagram showing the servo press apparatus according to the first embodiment of the present invention.

As shown in FIG. 1, the servo press device 1 includes a press mechanism 20, a servo motor 5 that operates the press mechanism 20, a control device 30 that supplies control power to the servo motor 5, and a press load of the press mechanism 20. The load cell 4 to detect and the rotational position sensor 6 are provided. Here, the servo motor 5 includes a motor shaft 5a that outputs motor rotation, and the rotational position sensor 6 detects the rotational position of the motor shaft 5a.

A power supply PS to which power is supplied is connected to the control device 30 through a power supply line L1, and the load cell 4 and the rotational position sensor 6 are connected through signal lines (L2, L3), respectively. The servo motor 5 is connected to the control device 30 by a power line L3. The control device 30 supplies control power to the servomotor 6 based on detection signals from the load cell 4 and the rotational position sensor 6.

Next, the press mechanism 20 provided in the press apparatus 1 will be described with reference to FIG.

As shown in FIG. 1, the press mechanism 20 includes a base plate 21, a ball screw 22, a screw nut 23, a driven pulley 24, a drive pulley 25, a belt 26, a main shaft 27, first and second linear motion members (28, 29). Is provided.

Here, one end of the ball screw 22 is rotatably supported on the base plate 21 and one end of the main shaft 27 is fixedly disposed. A driven pulley 24 is attached to the other end of the ball screw 22, and a drive plate 25 is attached to the motor shaft 5 a of the servo motor 5. A belt 26 is wound around the driven pulley 24 and the driving pulley 25, and the ball screw 22 is rotated via the belt 26 by the rotation operation of the motor 5.

A first linear motion member 28 is supported on the main shaft 27 so as to be linearly movable in the axial direction, and a screw nut 23 that is screwed into the ball screw 22 is attached to the first linear motion member 28. With the above configuration, the first linear motion member 28 moves linearly up and down by the rotation of the servo motor 5 to generate a press load.

The main shaft 27 supports the second linear motion member 28 so as to be linearly movable in the axial direction below the first linear motion member 28 (between the first linear motion member 28 and the base plate 21). And the movable jig 3 is below the first linear motion member 28, the fixed jig 2 is above the second linear motion member 29,
Each is attached. And the workpiece | work w distribute | arranged to the fixed jig | tool 2 is press-processed by the movable jig | tool 3 attached to the 1st linear motion member 28 which carries out a linear motion.

Here, the load cell 4 is disposed between the second linear motion member 28 and the base plate 21, and the press load of the press mechanism 20 is detected by the load cell 4.

Next, the control device 30 provided in the servo press device 1 will be described with reference to FIG.

The control device 30 includes a subtractor 31, a load controller 32, an adder 33, and a servo motor driver 34. Here, the subtracter 31 is supplied with a load command signal from an external device (not shown) such as a personal computer and a load detection signal from the load cell 4. Then, a process of subtracting the load detection signal from the load command signal is executed, and a load deviation signal is calculated based on the load command signal and the load detection signal. In addition, the memory which recorded the load command signal in the control apparatus 30 may be provided, and a load command signal may be supplied from this memory.

The load controller 32 is supplied with the load deviation signal from the subtractor 31, and calculates a predetermined rotation control signal based on the load deviation signal. Here, the rotation control signal is a command signal for additionally rotating the motor shaft 5a of the servo motor 5 by a predetermined angle (rotating by an additional rotation angle) in order to generate a press load corresponding to the load deviation signal. is there. Note that the command signal to be additionally rotated by a predetermined angle is a command signal converted by the reciprocal of the position proportional gain of the servo motor driver 34.

The adder 33 is supplied with a rotation control signal from the load controller 32 and a rotation position detection signal from the rotation position sensor 6. Here, the rotational position detection signal is a position signal indicating the current rotational position of the motor shaft 5 a of the motor 5. The adder 33 adds the rotation control signal to the rotation position detection signal, and calculates the rotation position command signal. Here, the rotational position detection signal calculates a rotational position command signal to rotate the motor shaft 5a of the servomotor 5 toward a predetermined rotational position (current rotational position + additional rotational angle).

The servo motor driver 34 is supplied with power from the power source PS, a rotational position command signal from the adder 33, and a rotational position detection signal from the rotational position sensor 6. Then, the servo motor driver 34 calculates the control power to rotate the motor shaft 5a of the servo motor 5 to the rotation position corresponding to the rotation position command signal, based on the rotation position command signal and the rotation position detection signal, Control power is supplied to the servo motor 6.

Next, a servo press apparatus 100 according to a second embodiment of the present invention will be described with reference to FIG. Here, FIG. 3 is a system block diagram showing a servo press apparatus according to the second embodiment of the present invention. The servo press device 100 of the second embodiment is different from the servo press device 1 of the first embodiment only in the control device, and the other parts are the same. Therefore, the control device 40 will be described, and the other parts will be denoted by the same reference numerals and description thereof will be omitted.

The control device 40 includes a subtracter 41, a load controller 42, an adder 43, a servo motor driver 44, and an output filter 45. Here, the subtracter 41 is supplied with a load command signal from an external device (not shown) such as a personal computer and a load detection signal from the load cell 4. Then, a process of subtracting the load detection signal from the load command signal is executed, and a load deviation signal is calculated based on the load command signal and the load detection signal. In addition, the memory which recorded the load command signal in the control apparatus 40 may be provided, and a load command signal may be supplied from this memory.

The load controller 42 is supplied with the load deviation signal from the subtractor 41, and calculates a predetermined rotation control signal based on the load deviation signal. Here, the rotation control signal is a command signal for additionally rotating the motor shaft 5a of the servo motor 5 by a predetermined angle (rotating by an additional rotation angle) in order to generate a press load corresponding to the load deviation signal. is there.

The adder 43 is supplied with a rotation control signal from the load controller 42 and a rotation position detection signal from the rotation position sensor 6. Here, the rotational position detection signal is a position signal indicating the current rotational position of the motor shaft 5 a of the motor 5. The adder 43 adds the rotation control signal to the rotation position detection signal, and calculates the rotation position command signal. Here, the rotational position detection signal calculates a rotational position command signal to rotate the motor shaft 5a of the servomotor 5 toward a predetermined rotational position (current rotational position + additional rotational angle).

The output filter 45 is supplied with the rotational position command signal from the adder 43 and undergoes the following processing.

The output filter 45 has a filter characteristic that compensates for the delay transmission characteristic of the press mechanism 20, corrects the rotational position command signal based on the filter characteristic, and outputs a corrected corrected rotational position command signal. The delay transmission characteristic is due to a power transmission element such as a belt 26 that inevitably expands and contracts in the press mechanism 20.

Here, the filter characteristic of the output filter 45 may be configured to correspond to a reverse transmission characteristic of the delay transmission characteristic of the press mechanism. The filter characteristic of the output filter 45 is expressed as an approximate delay transmission characteristic that approximates the delay transmission characteristic of the press mechanism 20 to a second-order delay system, and the reverse transfer characteristic of the approximate delay transfer characteristic expressed in the second-order delay system. May be set to a characteristic corresponding to.

The servo motor driver 44 is supplied with power from the power source PS, a corrected rotational position command signal from the output filter 45, and a rotational position detection signal from the rotational position sensor 6. Then, the servo motor driver 44 calculates the control power to rotate the motor shaft 5a of the servo motor 5 to the rotation position corresponding to the corrected rotation position command signal, based on the rotation position command signal and the rotation position detection signal. Control power is supplied to the servo motor.

The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Servo press apparatus, 2 Fixing jig, 3 Movable jig 4 Load cell, 5 Servo motor, 5a Motor shaft 6 Rotation position sensor 20 Press mechanism, 21 Base plate 22 Ball screw, 23 Screw nut 24 Drive pulley, 25 Drive pulley, 26 Belt 27 Main shaft, 28 1st linear motion member, 29 2nd linear motion member 30, 40 Controller, 31, 41 Subtractor 32, 42 Load controller, 33, 43 Adder 34, 44 Servo motor driver, 45 outputs Filter 100 Servo press, w Workpiece, PS Power supply

Claims (4)

Servo motor having a motor shaft, press mechanism operated by the servo motor, a load cell for detecting a press load of the press mechanism, a rotational position sensor for detecting a rotational position of the motor shaft of the servo motor, the load cell, and In a servo press device comprising: a control device that supplies control power to the servo motor based on a detection signal from the rotational position sensor;
The control device includes:
A subtractor for calculating a load deviation signal based on a load command signal and a load detection signal from the load cell;
Load control for calculating a rotation control signal for rotating the motor shaft of the servo motor by a predetermined angle from the reciprocal of the load deviation signal and a predetermined position proportional gain in order to generate a press load corresponding to the load deviation signal. And
An adder for calculating a rotational position command signal to rotate the motor shaft of the servo motor toward a predetermined rotational position based on the rotational control signal and a rotational position detection signal from the rotational position sensor;
A servo motor driver that calculates control power using the position proportional gain to rotate the motor shaft of the servo motor to a rotational position corresponding to the rotational position command signal, and supplies the servo motor to the servo motor. Servo press device. In the servo press device according to claim 1,
The control device includes:
A filter characteristic that compensates for a delay transmission characteristic of the press mechanism is configured, and includes an output filter that corrects the rotational position command signal by the filter characteristic and outputs a corrected rotational position command signal.
The servo motor driver is
A servo press apparatus for supplying control electric power to the servo motor to rotate the motor shaft of the servo motor to a rotation position corresponding to the corrected rotation position command signal. In the servo press device according to claim 2,
The filter characteristic of the output filter is a characteristic corresponding to a reverse transmission characteristic of the delay transmission characteristic of the press mechanism, or a reverse transmission characteristic of an approximate delay transmission characteristic approximating the delay transmission characteristic of the press mechanism to a second order delay system. A servo press device characterized by having corresponding characteristics . In the servo press apparatus according to any one of claims 1 to 3,
The press mechanism is
A ball screw rotated by the servo motor;
A screw nut screwed onto the ball screw;
A base plate that rotatably supports one end of the ball screw;
A main shaft having one end fixed to the base plate;
A first linear motion member that is integrally attached to the screw nut and linearly moves along the main shaft;
A second linear motion member disposed between the first linear motion member of the main shaft and the base plate;
Have
The servo press device according to claim 1, wherein the first linear motion member is linearly moved by the rotation of the servo motor to generate a press load.

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