JPH0610768B2 - Robot controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention has a function of instantaneously stopping the operation of a robot by pressing an emergency stop button when an emergency occurs, and is wasteful. The present invention relates to a control device for an industrial robot in which a returning operation is omitted.

[Conventional technology]

FIG. 5 is a block diagram showing a control device for a conventional industrial robot of this type. (1) is a main central processing unit (hereinafter referred to as main CPU) for overall control, and (2) is this main CPU. Read-only memory (hereinafter referred to as ROM) for storing the control procedure of (1), (3) is the main C
When the PU (1) controls the robot according to the contents of the ROM (2), a readable and writable memory (hereinafter referred to as RAM) used for temporarily storing data, (4) is the main CPU A timer for periodically inputting an interrupt signal to (1), and (5) a keyboard / C for inputting the robot's work procedure or displaying the current status.
RT (monitor TV), (6) is a teaching device used for manually operating the robot to teach a predetermined operation, that is, a teaching pendant, which also has an emergency stop button. (7) is an operation panel for making the robot perform various operations, (9) is a gate for inputting signals to the main CPU (1), (10) is a 0R gate, and (11) is other than the robot controller. Input device for inputting emergency stop signal from, (12)
Is a common signal line group (hereinafter referred to as a bus) that connects the main CPU (1) and various input / output devices.

Next, (20) is a servo CP that controls the servo of the robot.
U, (37) is a ROM for storing the control procedure of the servo CPU (20), (8) is the main CPU (1) and the servo C
RAM for communication with the PU (20), (21) a timer for periodically interrupting the servo CPU (20), and (22) a signal from the servo CPU (20). A latch for holding, (23) a digital-analog converter for converting the signal from the servo CPU (20) into an analog value (hereinafter referred to as a D / A converter), (24) a servo amplifier, (25) is a motor for driving each axis of the robot arm and hand device, etc. Although only one motor is shown in FIG. 5, in reality, the same number of motors as the number of robot axes is used. It goes without saying that they have it. (26)
Is a pulse encoder that converts the rotation of each motor (25) into a pulse train and outputs it, (27) is a brake, and (28) outputs a voltage proportional to the frequency of the pulse signal output from the pulse encoder (26). Frequency-voltage converter (hereinafter referred to as F / V converter), (29) is the pulse encoder (2
Directional discrimination circuit for separating the pulse signal output from 6) into positive and negative direction pulses, (30) is this direction discrimination circuit (29)
Up / down counter that counts positive and negative pulses output from the servo CPU (20),
It is a bus that connects each input / output device.

Next, (15) and (16) are the above teaching pendants.
(6) and the emergency stop signal output from the operation panel (7), (17) the emergency stop signal input from the outside, (34) the servo amplifier error signal output from the servo amplifier (24) This signal is an error signal output when the servo amplifier detects an abnormality in the servo system such as overcurrent or overload. (35) is a voltage signal output from the D / A converter (23) and input to the servo amplifier (33), which corresponds to a speed command. (36) is a speed feedback value output from the F / V converter (28), which corresponds to the feedback of the speed of the motor.

Next, (32) is a brake ON / OFF signal for controlling brake “ON” and “OFF”, and (33) enables or disables the operation of the servo amplifier for the servo amplifier (24). Servo ON / OFF signal for instructing whether to turn it on, (13) is the output of the OR gate (10). This is when a servo error or the emergency stop button is pressed or an emergency stop signal is input from the outside. , An emergency interrupt signal for interrupting the main CPU (1), and (14) and (38) are timer interrupt signals to the main CPU (1) and the servo CPU (20).

The conventional robot control device is configured as described above, and normally the main CPU (1) is not
After the teaching operation using the pendant (6) or the keyboard / CRT (5) and the position is read out by the RAM (3) for one operation, it is converted into a speed pattern to realize this, and then it is converted to each axis. Convert to each speed pattern. Then, the speed pattern is divided into values at regular time intervals, and R is output each time the timer interrupt signal (14) is output.
A position command to be actuated at regular intervals is output to the servo CPU (20) via the AM (8). on the other hand,
The servo CPU (20) divides the position command value into finer values for each time, takes the difference from the position feedback value obtained from the up / down counter (30), and further calculates it by a timer interrupt signal ( Each time 38) is output, it is output as a voltage signal, that is, a speed command (35) to the servo amplifier (24) via the D / A converter (23). Also, servo amplifier (24)
In, the difference between this speed command (35) and the speed feedback value (36) obtained from the F / V converter (28) is taken as the current command, and the motor (25) is controlled based on that. Has been done.

By controlling the motor (25) according to the procedure described above, the robot performs a predetermined work.For example, during this work, the servo amplifier (24) fails, or the pulse encoder (26). The motor (25) may run away due to a broken line from the robot, or the robot arm may try to move to the wrong position due to an incorrect teaching operation. In preparation for this, the industrial robot is configured so that when a serious failure such as a failure of the servo amplifier occurs, the operator presses the emergency stop button to instantly stop the operation of the robot. That is, as shown in FIG. 5, for example, when an emergency stop button (not shown) provided on the teaching pendant (6) is pressed, an emergency stop signal (15) is output and the OR gate (10) is output. An interrupt signal is input to the main CPU (1) via this, this main CPU (1) interrupts the current processing, and commands the servo CPU (20) to turn the servo "OFF" and brake "ON". Is output to instantly stop the robot arm.

[Problems to be Solved by the Invention] When the robot is stopped by the means described above, the inertia force is suppressed only by the brake, but the stop distance is an emergency stop using a normal servo. Compared with the means (hereinafter referred to as emergency stop means), the stop distance is usually longer as shown in the timing chart of FIG. On the other hand, if the emergency stop means is used by using the servo as described above, it is impossible considering the failure of the CPU and the servo amplifier. Also, if the robot is stopped by pressing the emergency stop button, it is not possible to confirm whether the control system is operating smoothly after the emergency stop. If you do not do this, there is a drawback that you cannot return to normal operation.

The present invention has been made by paying attention to such a point, and although the above-mentioned conventional emergency stop means by a brake is effective in the case of a failure of the control system or the like, an unexpected robot due to a teaching mistake of an operator or the like. This is not preferable as a stopping method when the emergency stop button is pressed and the emergency stop button is pressed. This is because not only the stop distance becomes longer as described above, but also a troublesome origin return operation must be performed in order to return the robot to the original position.
This is because the operating efficiency of the robot is reduced.

[Means for Solving Problems] A robot control device according to the present invention includes a main CPU that integrally controls a robot, and a brake servo control means that servo-controls the robot and controls a brake that causes an emergency stop of the servo when an abnormality occurs. The servo CPU has and the main CPU to which an emergency stop signal from an emergency stop button of an operator is input when a serious failure occurs. The servo CPU issues a deceleration start command of a predetermined emergency stop pattern by the servo "ON" and the brake "OFF". When the emergency interruption signal is output to the monitor CPU and the emergency interruption signal is output to the monitor CPU, it is monitored whether or not the deceleration is started based on the deceleration start command after a lapse of a certain time after receiving the emergency interruption signal, and it is not decelerated Occasionally, a command for outputting a servo "OFF" and a brake "ON" is output to the brake servo control means. A ROM that stores a program and a monitor CPU that monitors the servo control of the servo CPU and executes the program of the ROM when the emergency interrupt signal output from the main CPU is received.

[Operation] In the robot controller according to the present invention, when an emergency stop signal from the operator's emergency stop button is input to the main CPU when a serious failure occurs, the main CPU causes the servo "ON",
When the brake is "OFF", a deceleration start command of a predetermined emergency stop pattern is output to the servo CPU and an emergency interrupt signal is output to the monitor CPU, and the monitor CPU is stored in the ROM when the emergency interrupt signal is received. When a certain time has elapsed since the emergency interrupt signal was received and the deceleration start command was used to monitor whether or not the servo system is still being used for deceleration after a certain period of time has elapsed and it is determined that it will not be decelerated and will not stop For the first time, the command of the servo "OFF" and the brake "ON" is output to the brake servo control means to switch to the stop by the brake, so that the operator can press the emergency stop button when a serious failure of the robot controller occurs. When pressed, it may stop due to an emergency stop pattern, and the stop distance due to the stop of the brake It is possible to determine whether or not the home return is necessary by determining whether the robot has stopped normally by an emergency stop pattern or stopped by the brake by the servo "OFF". The home return operation can be omitted.

[Embodiment of the Invention] FIGS. 1 to 4 show an embodiment of the present invention. FIG. 1 is a block diagram showing a robot controller of the present invention, FIG. 2 and FIG. FIG. 4 is a timing chart for explaining the operation in the case of an emergency stop, and FIG. 4 is a flow chart for explaining the operation of the robot control device according to the present invention. The description of each member is omitted.

First, in FIG. 1, (40) is a monitor CPU provided to monitor the operation of the servo system, and (41) is this monitor C.
A ROM for storing the control procedure of the PU (40), and (42) for temporarily storing data when the monitor CPU (40) monitors the servo system according to the contents of the ROM (41). RAM, (43) a timer for periodically outputting an interrupt signal to the monitor CPU (40), (44) a latch for holding the output signal of the monitor CPU (40), and (45) a servo amplifier ( An analog-digital converter (hereinafter referred to as an A / D converter) for converting the speed command (35) input to 24) and the speed feedback value (36) to a digital value (46) is the above A bus for connecting the monitor CPU (40) and each input / output device, (47) a control circuit for controlling operations of a brake, a servo amplifier and the like, (48) a monitor CPU
A timer interrupt signal to (40), (49) is a signal from the monitor CPU (40) to the main CPU (1), and (50) is a signal for controlling the brake and the servo amplifier.

Since the robot control device of the present invention is configured as described above, the emergency stop signal (16) is now output by pressing the emergency stop button (not shown) provided on the operation panel (7). Then, this emergency stop signal becomes an emergency interrupt signal (13) via the OR gate (10), and when this is input to the main CPU (1), this main CPU (1) becomes a conventional one. In contrast, the emergency stop pattern is output as shown in the time chart of FIG. 2 while the servo is “ON”. At the same time, the emergency interrupt signal (13) is input to the monitor CPU (40). After that, the monitor CPU (40) displays the speed command value (35) and the speed feedback value.
(36) is compared, but if the difference is extremely large, the emergency stop signal (4) is sent to the main CPU (1) via the gate (9).
Enter 9) to stop the robot in an emergency. In the case of such an emergency interrupt, the operation is performed as shown in the flowchart of FIG. That is, when the emergency interrupt signal (13) is input, after a certain time “td” has elapsed in step (101) of the flowchart, the next step (10
In 2), check whether the speed command value (35) is starting to decelerate according to the emergency stop pattern. If the deceleration is not started, the command for servo “OFF” and brake “ON” is immediately input to the brake / servo amplifier control circuit (47) in step (106) and is unrelated to the speed command (35). The servo is turned off and the brake is applied to stop the robot operation.

In step (102) of the flowchart, if the speed command (35) is decelerating according to the emergency stop pattern, the speed feedback (36) is checked this time, and the speed command (3
Check to see if you are following 5) with a certain amount of difference. If it is not following, go to the next step (106) and if it is following, check whether the speed feedback value (36) is "0" in step (104). If the next step (105)
After waiting for a certain time at step (102)
The following is repeated. If the speed feedback value becomes "0", the next step (107)
And returns to normal monitor operation.

It should be noted that FIG. 2 shows an example of the normal stop in the emergency stop pattern when an emergency interrupt occurs.
The figure shows an example where an emergency interrupt occurs when the motor (25) begins to run away due to some failure.
In addition, the return from the emergency stop state described above
Whether or not U (1) is normally stopped by the emergency stop pattern by the signal (49) from the monitor CPU (40) or stopped by the brake by the servo "OFF" is used to determine whether or not the origin return operation is necessary. Since the determination can be made, useless operations can be omitted. Furthermore, the processing after the emergency interrupt input is processed by the main CPU (1) and the servo C.
Since the monitor CPU (40) separate from the PU (20) manages it,
It goes without saying that even if either the main CPU (1) or the servo CPU (20) fails, the robot can be surely stopped. The monitor CPU
As described above, (40) is normally operated by the main CPU (1) and the servo CPU (20) even during normal operation.
It is designed to check for abnormalities.

〔The invention's effect〕

As described above, according to the present invention, when a serious failure occurs, the emergency stop signal from the operator's emergency stop button is transmitted to the main CP.
When input to U, the main CPU causes the servo "O
When the deceleration start command of a predetermined emergency stop pattern is output to the servo CPU with "N" and the brake "OFF", an emergency interrupt signal is output to the monitor CPU, and the monitor CPU stores the ROM in the ROM when the emergency interrupt signal is received. Execute the stored program, and after a lapse of a certain time after receiving the emergency interrupt signal, monitor whether or not the servo system is being decelerated by utilizing the servo system as it is based on the deceleration start command. When doing, the servo "OFF" for the brake servo control means for the first time,
Since the brake "ON" command is output to switch to the stop by the brake, when the operator presses the emergency stop button when a serious failure of the robot controller occurs, the stop may be due to the emergency stop pattern. , The chance that the stopping distance becomes longer due to the stop of the brake is reduced, and it is judged whether or not the origin return is necessary by judging whether it stopped normally by the emergency stop pattern or stopped by the brake by the servo "OFF". As a result, it is possible to omit an unnecessary return-to-origin operation of the robot.

[Brief description of drawings]

1 to 4 all show an embodiment of the present invention. FIG. 1 is a block diagram of a robot controller, and FIGS. 2 and 3 are for explaining the operation in case of an emergency stop. FIG. 4 is a flow chart for explaining the operation of the robot controller. FIG. 5 is a block diagram showing a conventional robot controller, and FIG. 6 is a timing chart for explaining its operation. In the figure, (1) is the main CPU and (20) is the servo CP.
U, (40) monitor CPU, (41) ROM, (42) RA
M, (43) is a timer, (44) is a latch, and (45) is an A / D converter. The same reference numerals in the drawings indicate the same or corresponding parts.

Continuation of the front page (56) Reference JP-A-59-81706 (JP, A) JP-A-55-39944 (JP, A) JP-A-59-69296 (JP, A) JP-A-57-75313 (JP , A) JP 59-202509 (JP, A) JP 56-152005 (JP, A) JP 59-216206 (JP, A) Actual development Sho 52-38592 (JP, U) "Industrial Robot Safety Management: Its Theory and Practice "May 16, 1984, Central Industrial Accident Prevention Association, page 85

Claims (1)

[Claims] Claims: 1. A main CPU that controls the robot as a whole, a servo CPU that has brake servo control means that servo-controls the robot and controls a brake that makes an emergency stop of the servo when an abnormality occurs, and an emergency stop of an operator when a serious failure occurs. The main CPU, to which the emergency stop signal from the button is input, turns off the servo.
When the brake "ON" outputs a deceleration start command with a predetermined emergency stop pattern to the servo CPU and also outputs an emergency interrupt signal to the monitor CPU, deceleration starts after a lapse of a certain time after receiving the emergency interrupt signal. A ROM storing a program for monitoring whether or not the vehicle is decelerated based on the command, and outputting a command for servo "OFF" and brake "ON" to the brake servo control means when the vehicle is not decelerated, and the servo CPU Servo control is monitored and the main C
A robot controller comprising: a monitor CPU that executes a program in the ROM when the emergency interrupt signal output from the PU is received.