JPS62124897A - Safety device for robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a safety device that prevents a collision between a robot and a stocker that exchanges workpieces with the robot.

[Prior Art] In recent years, robots have been used to transport workpieces in processing machines. This robot normally operates automatically according to a preset or taught operation program.

On the other hand, a stocker, which is within the operating range of the robot, has a work loading and unloading position for the robot, and carries in and out unprocessed workpieces or completed workpieces and stores them, and operates under control separately from the robot.

Therefore, when the robot approaches the stocker to deliver a workpiece, if the timing of the robot's movement and the stocker's loading/unloading movement do not match, the two may collide, which is extremely dangerous. This may cause serious damage to the robot.

Therefore, it is necessary to prevent collision between the two.

Conventionally, as a means to achieve this objective, a worker monitors the movement of the robot and the stocker, and if there is a risk of collision, the worker presses the robot's emergency stop button to bring the robot to an emergency stop. ing.

Furthermore, as another means, it has been considered to control both the robot and the stocker using the same sequence operation program.

[Problems to be Solved by the Invention] However, among the above-mentioned conventional means, those that rely on worker monitoring require constant monitoring by workers, even though they are automatic devices, and require a large number of robots. If such a system were installed, a large number of workers would be required for monitoring, which would be unreasonable.

Additionally, when a robot is brought to an emergency stop, the power to the entire robot is cut off, so the motion program stored in the robot's control unit is erased, making it necessary to teach the motion or load the program again. ,
The disadvantage is that it is very time consuming.

Furthermore, when controlling both the robot and the stocker using the same sequence motion program, there is a large degree of freedom in the motion of both, and in order to control them in common, an extremely complex and lengthy motion program is required. This has the disadvantage that it takes time to create a program, requires a large amount of memory to load it, and as the program becomes more complex, the CPU processing time increases. .

The present invention has been made to solve the above problems, and allows the robot and the stocker to be controlled by their own sequence operation programs, making the programs short and simple, and facilitating their production and loading. At the same time, CPU processing time can be shortened, worker monitoring can be omitted, and automatic operation can be streamlined, and emergency stoppages that require time and effort to restore can be avoided as much as possible. The purpose is to provide a safety device for robots that has improved safety.

[Means for Solving the Problems] The present invention provides a robot that automatically sequentially supplies workpieces to a processing machine, which is within the operating range of the robot, has a workpiece attachment/detachment position, and has a workpiece loading/unloading position of the robot. As a means for solving the above-mentioned problems in a safety device that includes a stocker that stores processed workpieces or completed workpieces, and a loading/unloading device that supplies the workpieces from outside the stocker to the workpiece loading/unloading position inside the stocker, a first detection means for detecting that the position of the robot arm is in the vicinity of the work loading/unloading position in the stocker; a second detection means for detecting that the position of the robot arm is in the vicinity of the stocker; When the loading/unloading device is in operation, a control means is provided for commanding the robot to make an emergency stop using a signal from the first detecting means, and commanding the robot to temporarily stop using a signal from the second detecting means. Features.

[Operation] The present invention provides a stocker in which a robot that automatically sequentially supplies workpieces to a processing machine is within the operating range of the robot, has a workpiece attachment/detachment position, and stores unprocessed workpieces or completed workpieces. This is to prevent collisions with the A workpiece is supplied to the workpiece attachment/detachment position in the stocker from outside the stocker by a loading/unloading device.

In such a situation, if the position of the robot arm is near the work loading/unloading position in the stocker, this is detected by the first detection means. Furthermore, when the robot arm is located near the stocker, this is detected by the second detection means.

When the carrying-in/out device is operating, the control means detects by the first detection means that the position of the robot arm is near the work loading/unloading position in the stocker;
The detection signal commands the robot to make an emergency stop. Also,
When the control means detects that the position of the robot arm is near the stocker by the second detection means,
The detection signal commands the robot to pause.

Usually, the second detection means is activated first, so in most cases the robot receives a temporary stop command. Then, only in the case of an abnormal situation, an emergency stop is performed by the detection signal of the first detection means, so an emergency stop that requires time-consuming recovery work is extremely rare.

Further, since the mutual relationship between the robot and the stocker is detected by the first and second detection means, and the movement of the robot is regulated by the control means, it is not necessary to share the operation program for both, and each Can be set independently.

[Example] Embodiments of the present invention will be described with reference to the drawings.

[Example] An example of the present invention will be described with reference to FIGS. 1 and 2. Note that FIG. 1 is a block diagram showing an embodiment of the robot safety device of the present invention, and FIG. 2 shows an outline of a loading/unloading device C for loading/unloading a workpiece platform B on which a plurality of workpieces W are placed in the direction a. FIG.

<Configuration of the Embodiment> The robot safety device of the present invention shown in FIG. It has a function to avoid collision with the stand. In addition, as shown in Fig. 2, the workpiece stand B is a linear drive device (reciprocating cylinder, etc.)
71, the kite 72.moves into and out of the operational danger zone A along 72.

First, an overview of the configuration of the apparatus of this embodiment will be explained with reference to FIGS. 1 and 2.

This embodiment is applied to a robot consisting of a robot body Rh and an arm Ra rotatably provided on the robot body Rh. Its main components include a control unit 10 that constitutes the control means, photoelectric detectors 20a and 20b that constitute the first detection means, and photoelectric detectors 21a and 21b that constitute the $2 detection means. , an encoder 30 that detects the arm rotation angle, a drive control device 40 that controls the drive of the robot, a teaching operation panel 50 that teaches the robot movement, and a drive direction detection means that drives the robot arm Ra to rotate. and a driving device 60.

Next, the above configuration will be explained in more detail.

Regarding the range in which the arm Ra of the robot above rotates,
The operating dangerous range A is defined as a turning locus whose turning radius is the state in which the arm Ra is extended to its maximum extent.

The control unit IO includes CPU 41. Latch circuit 12゜1
3. Display device 14a, keyboard 14c, input/output circuit 14b, ROM (read only memory) 15, external storage device 16, and input interface 1
7 and an input/output interface 18, which are connected by a bus BUS.

The CPU II controls various devices connected to the control unit 10. For example, it has functions such as input/output control of various signals, latch control of robot detection signals, and outputting commands for controlling robot operations based on robot detection signals. The ROM 15 stores a program that controls the CPU 1l.

The latch circuit 12 has an internal latch memory, and holds the second detection signal when it is input. The latch circuit 13 holds signals related to other robot movements.

The photoelectric detectors 20a and 20b are arranged near the workpiece stand B that constitutes the stocker operated by the loading/unloading device C, that is, near the workpiece loading/unloading position in the stocker, and when the robot arm Ra passes over it, The structure is such that the change in brightness caused by the shadow is photoelectrically detected and a detection signal is output.

Further, the photoelectric detectors 21a and 21b are arranged outside the photoelectric detectors 20a and 20b, that is, near the inside of the stocker, and when the robot arm Ra passes over them, changes in brightness due to the shadow are detected photoelectrically. The structure is such that it detects the current and outputs a detection signal.

Each photoelectric detector 20a, 20b, 21a,
21b are all connected to the input interface 17,
The detection signal is input to the control section 10 mentioned above. The input interface 17 connects each photoelectric detector 20a, 20b
, 21a, and 21b are numerically coded and sent to the CPU 11.

The encoder 30 includes, for example, a disk 31 on which a certain code pattern is formed by through holes, shading marks, etc., and a code pattern reading element 3 such as a photocoupler or a reed switch.
2. The output of the reading element 32 is taken into the control unit 10 via the input/output interface 18,
It is used for motion control as a signal to notify the robot's current position.

The drive control device 40 of the robot Rh is connected to the CPU II via the input/output interface 18, and controls the drive device 60 according to instructions thereof. Further, a teaching operation g150 is connected to this drive control device 40. This teaching operation panel 50 is used to indicate whether the robot should be operated normally or not.
A mode selector 51 is provided for selecting a teaching operation.

The drive device 60 includes a motor 6 that rotates the robot arm.
1, an amplifier 62 for driving the motor 61, a speed detector 63 for the motor 61, and an interpolator 64 for distributing pulses and the like.

<Operation of the embodiment> Next, the operation of the apparatus of the embodiment configured as described above will be explained.

The CPU 11 executes various controls according to programs stored in the ROM 15. That is, external storage device 1
A robot operation program is read from 6, and a control signal is outputted to cause the robot to sequentially execute the operations of the program. On the other hand, the actual operating state of the robot in response to these control signals is detected by signals from the encoder 30, etc., and feedback control is performed.

Further, when the stocker stand B is operated by the loading/unloading device C, the CPU II monitors for abnormal proximity of the robot and the force. That is, the photoelectric detector 20a
, 20b, 21a, 21b and store these signals in the latch circuit 12,
The operation of the robot is stopped depending on the state of the detection signal. This operation will be explained in further detail.

Here, it is assumed that the arm Ra of the robot turns and passes over the photoelectric detector 21a. As a result, the photoelectric detector 21
Since the shadow of arm Ra enters a, the photoelectric detector 21
a detects the passage of arm Ra.

This detection signal is input to the input interface 17,
It is converted into a predetermined signal code. Input interface 1
7 outputs an interrupt request signal to the CPU II. C
PUII performs interrupt processing and accepts this request.
The detection signal from the input interface 17 is transferred to the latch circuit 12 via the bus and stored and held in a predetermined area.

The CPU II then sends a stop signal to the drive control device 40 to temporarily stop the robot. Drive control device 4
0 receives this signal and stops the robot.

These states are displayed on the i-isplay device 14a via the input/output circuit 14b.

In this state, when the position of the workpiece stand B moves out of the dangerous operation range A, a release signal is input from the workpiece stand B side to the input interface 17. This release signal is
When sent to I, the latch of the detection signal held in the latch circuit 12 is reset, and the stop signal to the drive control device 40 is released.

Therefore, the CPU II returns to the state before the interrupt processing and resumes the operation of the robot.

By the way, although it is extremely rare, there is a possibility that the arm will be detected by the next photoelectric detector 20a before the robot is temporarily stopped due to, for example, an abnormally high robot rotation speed. In this case, a detection signal is sent to the CPU 11 by one interrupt in the same manner as described above. If you receive this, CP
UII immediately turns off the power switch and brings the robot to an emergency stop.

Therefore, in this example, under normal conditions, the robot:
By temporarily stopping, collision with the stocker is prevented. In addition, in an abnormal situation, a collision is prevented by an emergency stop.

[Effects of the Invention] As explained above, the present invention enables the robot and the stocker to be controlled by their own sequence operation programs, shortens and simplifies the programs, and facilitates their production and loading. , CPU processing time can be shortened, and operator monitoring can be omitted.
It is possible to streamline operations through automatic operation, and also to avoid emergency stops that take time and effort to restore as much as possible2.
This has the effect of

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the robot safety device of the present invention, and FIG. 2 is a configuration diagram showing an outline of a workpiece table and a loading/unloading device that constitute a stocker. 11...CPU 12...Latch circuit 1
3...Latch circuit 17...Input interface

Claims (1)

[Scope of Claims] A robot that automatically sequentially supplies workpieces to a processing machine, which is within the operating range of the robot, has a workpiece attachment/detachment position, and stores unprocessed workpieces or completed workpieces. In a safety device equipped with a stocker and a loading/unloading device for supplying workpieces from outside the stocker to the workpiece loading/unloading position in the stocker, the robot arm is located near the workpiece loading/unloading position in the stocker. a first detection means for detecting a position of the robot arm; a second detection means for detecting that the position of the robot arm is in the vicinity of the stocker; A safety device for a robot, comprising: control means for instructing the robot to make an emergency stop; and control means for instructing the robot to make a temporary stop based on a signal from the second detection means.