JP3340095B2 - Automatic transfer control method and device for press - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling automatic transfer of a press related to an accident prevention system in an automatic transfer machine for a press.

[0002]

2. Description of the Related Art Conventionally, in a transfer press in an automatic transfer machine for presses, a plurality of dies are vertically arranged side by side, beam drive mechanisms are provided on both right and left sides of a press body, and feed is mechanically performed from a rotary shaft of the press. Bar lift elevating movement,
The three-dimensional movement of the forward and backward movement of the feed and the opening and closing movement of the clamp is combined and mechanically driven.

In the mechanical drive system of this transfer press, each step of three-dimensional movement such as lifting up and down, feed advance and retreat, and opening and closing of a clamp is determined by a cam curve. Therefore, the driving of the transfer can be executed under certain conditions according to the cam curve. However, depending on the type and size of the work (material) of the press, the die and the like must be replaced. Therefore, the cam curve differs depending on the mold to be replaced, and the gear and the cam must be replaced each time.

[0004] The exchange of the mold and the like requires a lot of work time and lowers productivity, and the cost of mechanical parts as spare parts is large, making maintenance and inspection complicated.

[0005] In recent years, the drive system of the transfer press has been switched from the mechanical drive system described above to an electric drive system using servo control in order to increase productivity or to cope with small-lot production of various types.

In this electric drive system using servo control, synchronous control by servo control is performed while each drive shaft of the transfer is synchronized with the rotation of the press using an individual electric motor.

The electric drive system using the servo control is as follows.
As described above, each drive shaft is driven by an individual motor, so the structure is simpler than the mechanical drive system, so no large mechanical parts are required, and the cost of maintenance parts is reduced. , Maintenance and inspection can be easily performed.

A position curve and a speed curve, which are motion curves of each drive of the electric drive type transfer using the servo control, are constructed by software. Since each drive shaft is driven by an individual electric motor, it is necessary to take measures to prevent an accident when an abnormality occurs between each drive shaft and the press.

When an abnormality occurs in each of the drive shafts and the press, in the abnormality detection method of the transfer press, a certain abnormality detection range such as a speed (rotation of a motor), a torque, and a moving distance from each drive of the transfer. And outputs a stop signal.

For example, Japanese Patent Application Laid-Open No. Sho 60-44137 discloses that a value obtained by adding a predetermined value to a value set by a feed setting device (digital switch) and a current value obtained from a rotation amount of a motor are used. A method is disclosed in which a stop signal is output when the current value exceeds the added value by comparing with a comparator.

Japanese Unexamined Patent Publication No. Hei 3-226325 discloses a method of monitoring the position of a feed bar provided with a distance meter for measuring the position of the feed bar at a specific stop point in a series of operations of the feed bar. Is disclosed.

In Japanese Patent Application Laid-Open No. 7-275971, a torque value actually measured in normal operation for each predetermined transfer pattern is used as a standard torque value of the pattern, and an upper limit torque value obtained by adding or subtracting a preset deviation value to or from the standard torque value. Calculates and stores the allowable torque value range specified by the upper limit torque value and the lower limit torque value, compares the actual torque value measured each time a specific transfer pattern is actually operated with the allowable torque range, and detects the moment it deviates from this range Is disclosed.

The arithmetic circuit (CPU) of the conventional program controller using servo control cannot detect an abnormality in the arithmetic circuit itself because it is dedicated to control. Press failure could not be prevented.

[0014]

In any case, in the conventional method, when an error range (abnormality detection range) is exceeded from a target value, or an abnormality occurs in the arithmetic circuit (CPU) of the program controller. Later, since an abnormality is detected and a stop signal is output, there is a certain period of time before the stop. For this reason, it is possible to prevent breakage accidents in the low speed range, but it is not possible to completely prevent machine damage in the middle and high speed range. Therefore,
It is not possible to cope with measures to prevent accidents in transfer presses, which have become sophisticated and complicated, such as the size of transfer presses has been increasing.

It is an object of the present invention to solve these problems by synchronizing the speeds of the motors of the feed shaft, the lift shaft and the clamp shaft of the transfer with the angle of one rotation of the reference shaft of the press. Lift up and down,
An object of the present invention is to provide an automatic transfer control method and apparatus for a press that selects a transfer stop method according to the position of a press when an abnormality occurs during a process such as a feed forward / backward operation and a clamp opening / closing operation.

Another object of the present invention is to provide a check system based on software duplication, that is, to control an electric motor in a calculation circuit (CPU) of a program controller based on software for forming a position curve and a speed curve for each drive shaft. The check arithmetic circuit, which stores the position curve and the speed curve corresponding to each drive shaft, stores the data of the control arithmetic circuit to be controlled and the value of the position curve or the speed curve stored by itself, and the value of the reference shaft one rotation of the press. A comparison operation is performed while synchronizing with the angle. If there is a difference between the data, it is judged that there is an abnormality, and at least a stop signal is output to prevent press and transfer accidents from occurring. An object of the present invention is to provide a transfer control method and apparatus.

[0017]

According to the present invention, a position curve and a speed curve in which the speed of an electric motor for driving a feed shaft, a lift shaft, and a clamp shaft of a transfer are synchronized with an angle of one rotation of a reference shaft of a press. Program to be formed
In an automatic transfer control device for a press having a controller, the speed of the electric motor of the feed shaft, the lift shaft, and the clamp shaft of the transfer is synchronized with the angle of one rotation of the reference shaft of the press, while the feed shaft is retracted, the clamp shaft is closed, and the lift is lifted. If an error is detected during the process of ascending the shaft → advance the feed shaft, stop the press, immediately stop the motors of the feed shaft, lift shaft and clamp shaft, and lower the lift shaft → open the clamp shaft. If an abnormality is detected in the press during the process of (1), the press is stopped, the motors of the feed shaft and the lift shaft are immediately stopped, and the motor of the clamp shaft continues the operation of opening the clamp for a certain period of time. It is characterized by the following.

Further, according to the present invention, each electric motor driving each drive shaft of feed, lift and clamp of transfer is provided.
An automatic transfer control device for a press having a program controller for forming a position curve and a speed curve synchronized with an angle of one rotation of a reference axis of a press of a press , wherein two program controllers are provided, and the two programs are provided.
・ The position and speed curves of each motor are stored in the controller.
Control arithmetic circuits for controlling the motor based on
A certain motor to one program controller
When the control arithmetic circuit for controlling is provided,
A check operation circuit for storing a position curve and a speed curve corresponding to the certain electric motor , wherein the check operation circuit includes
The check arithmetic circuit stores the data controlled by the position curve or the speed curve of the corresponding control arithmetic circuit provided in the program controller, the data of the position curve or the speed curve stored therein, and the reference of the press. Axis 1
The comparison is performed in synchronization with the rotation angle. If there is a difference between the data as a result of the comparison, it is determined that there is an abnormality, and at least a stop signal is output.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Control of a transfer press in an automatic transfer control device for a press according to an embodiment of the present invention will be described below.

FIG. 1 is a block diagram of a transfer press control device. This transfer press is composed of a press and a transfer. This press includes a press 1, a flywheel 2, a press motor 3, a pulse encoder 4 for a press, and a serial / parallel converter 5.

As shown in FIG. 1, the transfer press of the transfer press includes a feed bar (A-axis, B-axis).
Motor 13, a pulse encoder 14, a drive circuit 12, and a control circuit 1
1, motors 23A and 23B for raising and lowering a feed bar (A axis and B axis) by a lift axis, and a pulse encoder 24
A, 24B, drive circuits 22A, 22B, control circuits 21A, 21B, electric motors 33A, 33B for opening and closing feed bars (A axis, B axis) with clamp axes, pulse encoders 34A, 34B, drive circuits 32A, 32B, And a control circuit 31A, 31B and a digital distributed control device 50.

Next, the operation of the transfer press will be described with reference to FIGS. FIG. 2 shows a control block diagram of the feed bar of the transfer, and FIG. 3 shows an operation diagram of the transfer press.

First, when the transfer press is returned to the home position, the press stops at the home position (approximately 280 °) and stops with the clutch engaged and the brake engaged, and waits. Similarly, the transfer waits in an operable state.

In this state, when the press is started to be driven (clutch on, brake released), the speed of the press starts to increase and reaches a certain speed (or higher). Following the movement of the press, the feed bar of the transfer starts a three-dimensional movement.

In the three-dimensional movement of the feed bar, as shown in FIG. 3, first, when the clamp shaft is driven, the clamp starts closing the clamp. When the clamp is closed, the lift shaft is driven. Start climbing. Then, the feed shaft is driven immediately when the lift is raised, and the feed bar starts to move forward.

When the feed bar is advanced, the lift shaft is driven immediately before the advance is completed, and starts to descend. When the lift is at the lower limit, the clamp starts to open. As soon as the clamp is opened, the feed bar starts retreating, and after retreating, starts closing the next workpiece with the clamp shaft.The transfer does not interfere with the press while the press is continuously driven. And repeat this.

Next, a digital distributed control device (hereinafter referred to as PSC) 50 which is a program controller used in the transfer press will be described with reference to FIGS. However, a detailed view of the entire PSC is not shown.

The PSC shown in FIG. 1 has various functions such as an arithmetic function, a speed control function, a torque control function, a positioning function, and a sequence function that can form a position curve and a speed curve. By combining these functions, multiple speed control circuits, torque control circuits, position control circuits, and sequence circuits can be configured,
Further, it can be used for multi-axis motor control.

Transfer using the PSC 50, that is, control by multi-axis motor control can be performed using five motors of feed (one axis), lift (two axes), and clamp (two axes).

This feed (one axis), lift (two axes),
The control by the motor control of the five axes of the clamps (two axes) is common.
A description will be given based on FIG. As shown in FIG. 2, the control circuit of the feed bar includes a feed motor 13, a pulse encoder 14, a drive circuit 12, and a control circuit 11,
Arithmetic circuit (CPU) 100 and D / A in PSC 50
And a converter 103.

As described above, when the press of the feed bar is started to be driven (the clutch is engaged and the brake is released), the press bar starts to rise. When the press starts to ascend, the pulse encoder 4 of the press rotates, generates a pulse, and inputs the pulse to the PSC 50. By the pulse input to the PSC 50, the feed bar is driven (forward) while following the press along the position curve.

This position curve sets the advance angle range of the feed bar, that is, the "a certain angle range" of one revolution of the reference shaft of the press, for example, the stroke (distance) of the start angle 300 ° and the end angle 60 °, Set the position stroke of the bar backward angle range, start angle 120 ° and end angle 240 °.

A position curve is created by a program from the set forward or backward “angle range” based on the number of pulses generated by the press pulse encoder 4, and stored in the arithmetic circuit 100. The stored position curve is converted to a speed curve by time differentiation, and is input to the D / A converter 103 as a digital speed signal. The digital speed signal input to the D / A converter 103 is converted to an analog speed signal, input to the control circuit 11, and
2 drives the electric motor 13.

As a correction for the position control, a position curve signal and a pulse signal from the pulse encoder 14 of the electric motor 13 are used to calculate the position, the position is corrected based on the value, and the drive is performed while following the movement of the press based on the position curve. . Similarly, three-dimensional movement is performed while following the movement of the press 1 in the same manner as lifting and lowering of the feed bar by the lift axes (A axis, B axis) and opening and closing of the feed bar by the clamp axes (A axis, B axis).

As described above, when the feed bar makes a three-dimensional movement while following the movement of the press, if an abnormality occurs, conventionally, when the feed bar exceeds an error range (abnormality detection range) from the target value, the abnormality occurs. A signal was output and the feed bar was stopped.

In the present invention, if an abnormality occurs while the feed bar follows the movement of the press, the stop signal is output immediately upon detection of the abnormality, and the press 1 is stopped to prevent danger in advance.

Since the press 1 is driven by the flywheel, it takes a certain stop time until it stops due to inertia. Depending on the position of the press 1 and the position of the feed bar, the press and the feed bar interfere. A method of stopping each motor of the feed bar to avoid this interference in advance will be described.

As shown in FIGS. 1 and 3, the transfer performs the following steps while the speed of the motor driving the feed shaft, the lift shaft, and the clamp shaft is synchronized with the angle of one rotation of the reference shaft of the press. repeat.

In this process, when the clamp shaft is driven, the closing of the clamp is started. When the clamp is closed, the lift shaft is driven and the lift starts to rise. Then, the feed shaft is driven immediately when the lift is raised, and the feed bar starts to move forward. The lift shaft of the feed bar that has advanced has started to descend immediately before the advance is completed, and the clamp shaft starts to open when the lift is at the lower limit. Immediately after the clamp is completely opened, the feed bar starts retreating. After the retreat, the clamp starts closing the next work by the clamp shaft, and while the press is continuously driven, the feed bar is pressed by the press 1
To follow without interference to, to repeat this.

According to the feed bar stopping method of the present invention, the feed shaft is retracted (return) → the clamp shaft while the feed bar is synchronized with the angle of one rotation of the reference shaft of the press.
Close → lift shaft rise → feed shaft advance (feed)
If an abnormality is detected in the transfer during the process, the press is stopped by the press stop signal. However, as described above, since the press 1 is driven by the flywheel, the inertia is large. It takes a certain amount of downtime.

Accordingly, the motors of the feed shaft, the lift shaft and the clamp shaft are immediately stopped so as not to interfere with the press. Thus, danger can be avoided without interference between the feed bar and the press.

Similarly, the feed bar is the reference axis 1 of the press.
When an abnormality is detected in the transfer during the process of lowering the lift shaft and opening the clamp shaft while synchronizing with the rotation angle, the press is stopped by the press stop signal, but the press 1 is driven by the flywheel. Because
Since the inertia is large, it takes a certain stop time to stop. Therefore, in order to prevent interference with the press, the motors of the feed shaft and the lift shaft are immediately stopped, and the motor of the clamp shaft does not use the absolute signals of the pulse encoder for the press and the pulse encoder of the motor.
Immediately continue the operation of opening the clamp with a fixed speed command to avoid danger. The operation of opening the clamp is terminated after a predetermined time has elapsed after outputting a stop signal to the press to avoid interference of transfer with the lowering of the press 1.

As described above, the feed bar can be safely stopped without interfering with the press 1.

Next, when an abnormality occurs while the transfer according to the present invention follows the movement of the press, a stop signal is issued to the press 1 to stop the press, and a program controller operation to prevent danger in advance. Circuit (CPU)
Will be described.

First, the position curve of the press for each drive shaft synchronized with the angle of one rotation of the reference shaft of the press will be described.
FIG. 4 shows a change in the rotation angle of the press 1. The vertical axis indicates the rotation angle of the press, and the horizontal axis indicates the time.
゜ indicates a state where the press is at the top dead center, and a rotation angle 180 ° indicates a state where the press 1 is at the bottom dead center.

The arithmetic circuit of the program controller is
The storage of the press rotation angle (reference axis input) input from the pulse encoder 4 of the press 1 is repeatedly executed every several mmSEC (in this case, every 2 mmSEC). This is the position curve of the press 1.

As another example, a speed curve will be described. The operation circuit of the program controller is Press 1
A position curve is set based on the pulse generated by the rotation of the pulse encoder 4 and the set position curve is converted into a speed curve by time-differentiating the set position curve. FIG. 5 shows an example of the speed curve of the press 1. The vertical axis indicates the pressing speed, and the horizontal axis indicates the time. The arithmetic circuit of the program controller updates the value of this speed curve every several mmSEC (in this case, 2 mmS
Calculated for each EC) and stored.

Next, a description will be given of a check system by duplicating software in the program controller. FIG. 6 shows an embodiment of the mutual check method of the program controller ( PSC ). FIG. 7 is a flowchart for explaining the operation of the mutual check of the arithmetic circuits of the program controller.

An embodiment using two PSCs as shown in FIG. 6 will be described. The PSC 50-1 controls the clamp shaft (two axes) with an electric motor, and the PSC 50-2 controls the feed shaft (one axis) and the lift shaft (two axes) with the electric motor.

The operation circuits 100-1 and PSC 50-2 of the PSC 50-1 form a position curve and a speed curve in which the speed of the motor driving each axis of the transfer is synchronized with the angle of the reference 1 rotation of the press 1. Arithmetic circuit 100-
2.

The operation circuit 100-1 of the PSC 50-1
The PSC 50- comprises a control arithmetic circuit for controlling the electric motor based on software for forming a position curve and a speed curve for each of the clamp axes (A axis, B axis).
2 has a clamp shaft (A
(A and B axes), each of which has a check arithmetic circuit for storing a position curve and a speed curve corresponding to each axis.

The operation circuit 100- of the PSC 50-2
The 2, provided each individual feed shaft and the lift shaft (A axis, B axis) of the control operation circuit for controlling the electric motor on the basis of the software forming the position curve and speed curve forming the respective axes, PSC 50 -1 arithmetic circuit 100-1 includes:
A check arithmetic circuit for storing a position curve and a speed curve corresponding to each of the feed axis and the lift axis (A axis, B axis) described above is individually provided.

As described above, each PSC has an individual arithmetic circuit (CPU), and a control arithmetic circuit for controlling the motor based on software for forming a position curve and a speed curve for each drive axis, and a control arithmetic circuit for each drive. A check arithmetic circuit that stores a position curve and a speed curve corresponding to each axis is relatively configured.

Next, a checking method will be described with reference to FIGS. 7, 8 and 9. For example, a clamp shaft (FIG. 7)
) Indicates that the signal of the press rotation angle (reference axis input) input from the pulse encoder 4 of the press 1 is a PSC 50-1.
And the arithmetic circuit 100-2 of the PSC 50-2.

The press rotation angle (reference axis input) signal (step 1) input to the PSC 50-1 is input to a control arithmetic circuit for each of the clamp axes (A axis and B axis), and (A axis, B axis) The motor is controlled based on the position curve and the speed curve for each axis (step 2). Also, P
Press rotation angle input to SC 50-2 (reference axis input)
Is the clamp axis of PSC 50-2 (A axis, B axis)
The position and speed curves corresponding to each of the clamp axes (A-axis and B-axis) are also checked (step 3).

Then, the arithmetic circuit 100 of the PSC 50-1
-1 clamping axis (A axis, B axis) of the data controlled by the position curve and the speed curve of the control calculation circuit for each axis of the clamp shaft of the arithmetic circuit 100-2 PSC 50 - 2 (A axis, more check calculation circuits for storing positional curve and speed curve corresponding to each axis of the B-axis), the number of positions in synchronism with the angle of the reference axis one revolution of the press mmSE
The comparison operation is repeatedly executed for each C (in this case, every 2 mmSEC) (step 4). If they match each other, check repeatedly. If they do not match, a press stop signal is generated (step 5), and the press is stopped (step 6).

Next, the lift shaft (see FIG. 8)
PSC 50-2 Press rotation angle input (reference axis input)
(Step 1) is input to the control arithmetic circuit for each of the lift axes (A axis, B axis), and the lift axis (A axis, B axis)
The motor is controlled based on the position curve and the speed curve for each axis (step 2). The signal of the press rotation angle is inputted to the PSC 50-1 (reference axis input), PSC
The position curve and the speed curve corresponding to each of the lift axes (A-axis, B-axis) are inputted to the check arithmetic circuit for each of the lift axes (A-axis, B-axis) 50-1. (Step 3).

Then, the arithmetic circuit 100 of the PSC 50-1
The data controlled by the position curve and the speed curve of the control arithmetic circuit for each of the -2 lift axes (A-axis and B-axis) are represented by P
Lift shaft arithmetic circuit 100-2 SC 50 - 2 (A axis,
(B axis) The position is shifted by several mmSEC (in this case, every 2 mmSEC) in synchronization with the angle of one rotation of the reference axis of the press by a check arithmetic circuit that stores a position curve and a speed curve corresponding to each axis. (Step 4). If they match each other, check repeatedly. If they do not match, a press stop signal is generated (step 5), and the press is stopped (step 6).

[0059] Similarly, the feed axis (see FIG. 9) is, P
Press rotation angle input to SC 50-2 (reference axis input)
(Step 1) is input to the control arithmetic circuit of the feed shaft to control the electric motor based on the position curve and the speed curve of the feed shaft (step 2). Also, PSC 50
The signal of the press rotation angle (reference axis input) input to -1 is also input to the feed shaft checking arithmetic circuit of the PSC 50-1 to check the position curve and the speed curve corresponding to the feed axis (step). 3).

Then, the arithmetic circuit 100 of the PSC 50-2
A check arithmetic circuit for storing data controlled by the position curve and the speed curve of the control arithmetic circuit of the feed axis of -2 for the feed axis of the arithmetic circuit 100-1 of the PSC 50-1; The position is several mmSE synchronized with the angle of one rotation of the reference axis of the press.
The comparison operation is repeatedly executed for each C (in this case, every 2 mmSEC) (step 4). If they match each other, check repeatedly. If they do not match, a press stop signal is generated (step 5), and the press is stopped (step 6).

According to the above-described method, when an abnormality occurs while the transfer follows the movement of the press 1, it is possible to detect the abnormality and output a stop signal at the same time to stop the transfer press, thereby preventing the danger in advance. it can.

In the above-described check method based on software duplication in the program controller, the position is compared and calculated. However, it is apparent that the speed may be compared and calculated.

[0063]

According to the present invention, when an abnormality occurs during the lifting and lowering of the feed bar, the feed advance and retreat, and the opening and closing of the clamp, the method of stopping the transfer is selected according to the position of the press, and the program An abnormality can be detected by a check method based on software duplication in the controller, and the press can be stopped immediately to prevent occurrence of an accident.

[Brief description of the drawings]

FIG. 1 is a block diagram of a transfer press control device.

FIG. 2 is a control block diagram of a feed bar of a transfer.

FIG. 3 is a diagram illustrating an operation of a transfer press.

FIG. 4 is a diagram illustrating an example of a position curve.

FIG. 5 is a diagram showing an example of a speed curve.

FIG. 6 is a diagram showing an embodiment of a mutual check method of an arithmetic circuit (CPU) of a PSC.

FIG. 7 shows a PSC calculation circuit (CP
It is a figure which shows the flowchart of the mutual check of U).

FIG. 8 shows a PSC calculation circuit (CPU) in the lift axis.
It is a figure which shows the flowchart of mutual check.

FIG. 9 shows a PSC calculation circuit (CP
It is a figure which shows the flowchart of the mutual check of U).

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 press 2 flywheel 3 press motor 4 press pulse encoder 5 serial / parallel converter 11 control circuit 12 drive circuit 13 electric motor 14 pulse encoder 21A, 21B control circuit 22A, 22B drive circuit 23A, 23B electric motor 24A, 24B pulse encoder 31A , 31B Control circuit 32A, 32B Drive circuit 33A, 33B Motor 34A, 34B Pulse encoder 50 Digital distributed control device

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Kuramoto 2-3-3 Fukuura, Kanazawa-ku, Yokohama-shi, Kanagawa 2 Japan Reliance Co., Ltd. (56) References JP-A-8-19828 (JP, A) 9-314258 (JP, A) JP-A-2-263530 (JP, A) JP-A-10-71440 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21D 43/05

Claims (4)

(57) [Claims] 1. An automatic press machine having a program controller for forming a position curve and a speed curve in synchronization with the angle of one rotation of a reference shaft of a press of each electric motor driving each drive shaft of a transfer feed, lift and clamp. In the transfer control device, two of the program controllers are provided, and control arithmetic circuits for controlling the motors based on the position curve and the speed curve of each motor are separately provided in the two program controllers. When the controller is provided with a control arithmetic circuit for controlling a certain motor, the other program controller is provided with a check arithmetic circuit for storing a position curve and a speed curve corresponding to the certain motor The check operation circuit is provided in the one program controller. The check arithmetic circuit synchronizes the data controlled by the position curve or the speed curve of the corresponding control arithmetic circuit with the data of the position curve or the speed curve stored therein and the angle of one rotation of the reference axis of the press. Automatic transfer control method for a press, characterized in that if there is a difference between the data as a result of the comparison, it is determined that there is an abnormality and at least a stop signal is output. 2. If the above abnormality is detected during the process of lowering the lift shaft → opening the clamp shaft, the press is stopped, and the motors of the feed shaft and the lift shaft are immediately stopped, and the motor of the clamp shaft is stopped. The automatic transport control method for a press according to claim 1, wherein the operation of opening the clamp is continued for a predetermined time. 3. A control operation for forming a position curve and a speed curve of each electric motor for driving any one of a feed, lift and clamp of a transfer in synchronization with an angle of one rotation of a reference shaft of a press. A first program controller having a circuit, and a position curve and a speed curve of each electric motor driving each of the remaining drive shafts of the transfer feed, lift and clamp, which are synchronized with the angle of one rotation of the reference shaft of the press. A second program controller having a control arithmetic circuit to be formed, wherein the first program controller has a position curve and a speed corresponding to a motor controlled by the control arithmetic circuit of the second program controller. First to memorize curve
The second program controller stores a position curve and a speed curve corresponding to a motor controlled by the control calculation circuit of the first program controller.
Wherein the first and second check arithmetic circuits are respectively controlled by a position curve or a speed curve of a corresponding control arithmetic circuit provided in the other program controller. Is compared with the data of the position curve or the speed curve stored therein, while synchronizing with the angle of one rotation of the reference shaft of the press. As a result of the comparison, if there is a difference between the data, it is determined that there is an abnormality. And outputting at least a stop signal. 4. If the abnormality is detected during a process of lowering the lift shaft → opening the clamp shaft, the press is stopped, and the motors of the feed shaft and the lift shaft are immediately stopped, and the motor of the clamp shaft is stopped. The automatic transfer control device for a press according to claim 3, further comprising: means for continuing the operation of opening the clamp for a predetermined time.