JPH03104581A - Robot control system - 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] [Industrial Application Field] The present invention positions a moving body such as a robot hand at a final target position according to a movement path determined by a pre-designated target position, and causes the robot hand to grip a component, etc. , regarding a robot control system that performs a predetermined work such as transport to an assembly position, more specifically, when the movable body is brought to an emergency stop, the movable body deviates from the planned path due to the inertia of the movable body, etc. The present invention relates to a robot control system configured to easily and safely return the movable body to the position at the time when an emergency stop signal was detected even when the movable body has stopped, and then restart the movable body.

[Prior Art] Conventionally, a moving body such as a robot hand is positioned at a final target position according to a movement path determined by a pre-designated target position, and a moving body such as a robot hand is gripped and transported to an assembly position. Robot control systems for performing work are widely used in various manufacturing factories.

For example, such robot control systems are used in the automobile industry, where a seat is supplied to a predetermined location and is gripped by a robot hand, and then transported to a position on the vehicle body by a belt conveyor or the like. Various processes such as assembly are automated by robot control systems.

By the way, in such a robot control system,
If the robot hand comes into contact with the workpiece, a malfunction or abnormality occurs in the robot hand's attached parts, the operator's operation, or the system's 7 fail-safe function causes the problem.
The robot hand may come to an emergency stop. At this time, the robot hand will deviate from the specified movement path due to its inertia and stop. Especially in robots that handle heavy seats or car bodies, the inertia is large and the stopping position may deviate greatly from the planned path. Become.

As is well known, in the robot control system of the teaching playback system, an operator moves the robot in advance, stores information such as target position information indicating a predetermined path, desired work content, and work order, and sequentially reads out the information. , the robot hand is moved along a predetermined movement path and is made to perform a predetermined task.

For this reason, the main part of the control is generally configured with a microcomputer, etc., and the contents taught by teaching are stored in the storage device of the microcomputer, and are executed by pressing the start key on the operation table. The robot is configured to read out data sequentially according to a playback program and operate the robot as scheduled.

In this type of robot, if the robot hand is to restart after the emergency stop as described above and the cause of the stop has been resolved, the teaching data, that is, the instruction to restart from the beginning (starting end) of the preset movement path, is required. It was extremely difficult to start from a stopped position.

Furthermore, even if it is set to restart from the stopped position, as mentioned above, there will be a large deviation from the position of the robot hand at the time the stop signal was detected to the position where the robot hand is actually stopped due to inertia. If there is
If the robot hand restarts from the position where it is currently stopped, it will move off the planned path and there is a risk of contact (interference) with the workpiece or contact with other workers. , there was a big problem in terms of safety.

In order to alleviate this problem, for example, JP-A-60-123
As in the technical idea described in Publication No. 905, after determining whether the stopping position is within the scheduled range, if the stopping position is within the scheduled range, the system restarts from the stopping position. There is a structured robot control method.

[Problems to be Solved by the Invention]However, with this control method, depending on the stopping position, it may not be possible to restart from the stopping position, which poses a practical problem. In other words, according to the conventional technology, if the position where the robot hand is currently stopped is significantly different from the position of the robot hand at the time the emergency stop signal was detected, it is not possible to restart the robot hand from that position. There was an inconvenience that there was no one.

Therefore, the present invention has been made to solve these problems, and it positions a movable body such as a robot hand at a final target position according to a movement path determined by a pre-designated target position, and removes parts, etc. In a robot control system that performs predetermined tasks such as gripping and transporting to an assembly position, when the moving object is brought to an emergency stop,
Even if the movable body deviates from the planned route and stops due to inertia of the movable body, the movable body can be easily and safely returned to the position at the time when the emergency stop signal was detected, and then restarted. The purpose of this invention is to provide a robot control system configured to.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention positions a moving body at a final target position according to a movement route determined by a pre-designated target position, and moves the mobile body to a predetermined position. In a robot control system for performing work, the system includes a first storage unit that stores a final target position, a second storage unit that stores a current target position, and a second storage unit that stores a current position where the moving object is currently located. and a fourth storage unit that stores the position of the moving body at the time when the emergency stop signal is detected when the moving body is brought to an emergency stop as a return target position, When the signal is detected, the moving body is returned from the current position of the moving body stored in the third storage unit to the return target position stored in the fourth storage unit at a speed slower than the normal movement speed. After that, the moving body is positioned at the final target position stored in the first storage unit.

[Function] Since the robot control system according to the present invention is constructed as described above, it has the following functions. That is, when the robot hand (moving body) is brought to an emergency stop due to the above-mentioned causes, the position of the robot hand at the time when the emergency stop signal is detected is stored in the fourth storage unit as the target position to which it should be returned; The position where the robot hand actually stops due to inertia or the like is stored in the third storage unit as the current position. When the restart signal is detected, the robot hand is controlled to move from the current position of the robot hand stored in the third storage unit to the final target position stored in the first storage unit; Even if the actual stopped position of the robot hand deviates greatly from the planned movement route, the robot hand can be restarted from the stopped position very easily and safely.

Furthermore, even if an emergency stop occurs during the return operation to the return target position, the robot hand can be returned to the planned movement path by nesting and repeating the above operations multiple times.

[Example] Next, an example of a robot control system according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of an assembly robot system to which the robot control system according to the present embodiment is applied.

In the figure, reference numeral 10 indicates an assembly robot system to which the robot control system according to the present embodiment is applied, and in this assembly robot system 10, an assembly robot 14 is driven based on sequence control by a sequencer 12. In this case, the assembly robot 14 is taught its operation by the teaching box 18, and is driven and controlled by the hydraulic unit 22 via the robot controller 20.

Here, as shown in FIG. 2, the assembly robot 14 is arranged at a work station 24, and a vehicle body 30 is transported in a predetermined direction on an assembly line 26 by a transport device 28.
The task is to assemble the chassis 32 as a workpiece.

The work station 24 further includes a work stocker 34 for arranging a plurality of the chassis 32, and a jig holding mechanism 36 attached to the tip of the assembly robot 14 to hold the chassis 32. A jig stocker 40 is provided in which a plurality of jigs 38 are arranged. Note that when the jig 38 is supported via the jig holding mechanism 36 that constitutes the assembly robot 14, the supported jig 3
Since 8 functions as a robot hand (moving body), the supported jig 38 will be hereinafter referred to as a robot hand 38a for convenience (see FIG. 2).

Here, the operating state of the assembly robot 14 itself and each jig such as the robot hand 38a1, the workpiece stocker 34, and the jig stocker 40 is detected by sensors such as a potentiometer and a limit switch (not shown), and this detection signal is transmitted to the kneading board l3. The detection signal is sent to the sequencer 12 disposed within the robot controller 20, and the sequencer 12 executes the operation while checking the operating state of each part, and this detection signal is sent to the robot controller 20.

On the other hand, the movement of the assembly robot [4 is performed by operating the hydraulic unit 22, but the movement route and final target position, etc., are determined in advance by manually setting the teaching points while actually moving the assembly robot 14 using the teaching box l8. is stored in the robot controller 20, and the robot controller 20 adjusts the hydraulic unit 2 based on this taught point.
A teaching playback system is adopted in which the robot 2 is activated and the movement of the 7 assembly robots 14 is controlled. Note that the moving position of the assembly robot 14 is detected by a sensor (not shown), and is also fed back to the robot controller 20.

As shown in FIG. 1, the robot controller 20 includes an I/O processing section 42 that performs human output processing of control information and control data with external devices such as the teaching box 18 and the sequencer 12, and a hydraulic unit 22. A servo control unit that outputs signals based on teaching data or sequence programs to each hydraulic system such as a hydraulic motor and a hydraulic cylinder that make up the assembly robot 14 through the assembly robot 14, and receives response signals from the hydraulic unit 22. 44, and a main processing section 46 that exchanges necessary control information and control data with the ■/○ processing section 42 and the servo control section 44, and controls the overall operation of the assembly robot 14 and the work station 24. It is structured as follows.

The I/O processing section 42, servo control section 44 and main processing section 46 each have a microprocessor,
Data processing is possible independently.

The engineering/○ processing section 42 further includes an LCD display 4.
8. Numeric keypad 50 and floppy disk drive 5
2 are connected.

In addition, the ■/○ processing section 42 and the main processing section 46 are connected by a first dual port RAM 54, and the connection between the main processing section 46 and the servo control section 44 is via a second dual port RAM 54.
dual baud} RAM 56. And ■
/○ Between the processing section 42, main processing section 46 and servo control section 44, dual port RAM 54 and 5
6, control information and control data are exchanged. In this case, the dual port RAMs 54, 56 function as shared memory in a conventional multi-cPU system.

In addition, ■/○ processing section 42, main processing section 46, servo control section 44, dual baud} R A M54 and 56 are main boards (main wiring boards) not shown.
are arranged integrally on the top.

Teaching data such as the movement route, work order, and work content of the assembly robot } 14 created using the teaching box 18 is sent to the main processing section 46 via the ■/○ processing section 42 and stored in the main memory 58. Ru. Main processing section 46
sequentially reads out the teaching data stored in this main memory 58 and sends it to the I/O processing section 42 and the servo control section 4.
4, and controls the operation of the work station 24.

FIG. 3 is a schematic diagram for explaining the functions of the main memory 58 within the main processing section 46. As shown in FIG. In addition, in the configuration diagram of the main memory 58 shown in FIG. 3, in order to facilitate understanding of this embodiment, only the functional parts necessary for controlling the movement of the robot hand 38a are illustrated, and other functional parts are not shown. Omitted.

The main memory 58 includes a first storage section 58A that stores the final target position where the robot hand 38a is finally positioned;
A third storage unit 58C stores the current position of the robot hand 38a, and a second storage unit stores the current target position to which the robot hand 38a should move next at this current position.
A storage unit 58B and a fourth storage unit that stores a return target position to be described later.
It is composed of a storage section 58D. These final target position data and each target position leading thereto, that is, movement route data, are taught from the teaching box 18 as described above. Further, each position data is stored as position data between each axis of a three-dimensional orthogonal coordinate system.

When the robot hand 38a is brought to an emergency stop, the fourth storage unit 58D stores the position of the robot hand 38a at the time when the emergency stop signal is detected as a return target position to which the robot hand 38a should return when restarting.

The assembly robot system to which the robot control system according to the present invention is applied is basically constructed as described above, and its operation and effects will be explained next.

FIG. 4 is a diagram showing the movement path of the robot hand 38a. The robot hand 38a is currently specified to move from position A to position B through teaching points Nl, N2, . . . according to the teaching data. It is assumed that The earliest target position B of the robot hand 38H is stored in the first storage unit 58.
The teaching points N1, N2, . The target positions to which the robot hand 38a should be moved are sequentially read out. Robot hand 38a
The current position where is currently located is stored at address ○ in the third storage section 58C.

When the robot hand 38a is brought to an emergency stop for some reason, the position of the robot hand 38H at the time when the emergency stop signal was detected is stored in the fourth storage section as the return target position E to which the robot hand 38a should return after restarting. It is stored at address P of 58D. In the example of FIG. 4, suppose that while the robot hand 38a is moving from position A to position B along the planned route, an emergency stop signal is detected at the position.
The position E to which the robot hand 38a should return after restarting is stored at address P in the fourth storage unit 58D. Even if the emergency stop signal is issued at position E, the robot hand 38a cannot stop immediately, and due to its inertia, it deviates from the planned path and stops at position S. This current position is stored after address ○+1 in the third storage section 58C.

FIG. 5 is an operation flowchart of the robot control system during an emergency stop according to the present invention.

Normally, the robot hand 38a starts from the initial position A (FIG. 4), and the main processing section 46 stores the current position of the robot hand 38a stored in the third storage section 58C of the main memory 58 and the second storage section 58B. The target position is calculated from the current target position stored in
The robot hand 38a of No. 4 is moved toward the target position (STPI). When the emergency stop signal is not detected in step 2 and the current target position Ni is reached in step 3, the next target position NI is reached. 1 is given as the target position command, and this operation is repeated until the robot hand 38a passes through each previously taught target position (planned route) to the final target position B (FIG. 4) stored in the first storage unit 58A. When you move, the action is complete.

During this operation, when the operator presses the emergency stop button at position E in FIG. 4 for the reason mentioned above, this information is detected by the I/O processing unit 42, and the second dual
The data is sent to the main processing section 46 via the RAM 54. Alternatively, when an emergency stop command is issued by the safety function of the main processing section 46 and such an emergency stop signal is detected by the main processing section 46 in step 2, the current position of the robot hand 38a is is taken into the main processing section 46 from the servo control section 44, and stored as the return target position E in the fourth storage section 58D of the main memory 58 (STP5). In step 6, the process waits until the robot hand 38a comes to a complete stop. During this time, the robot hand 38a deviates from the planned movement path to positions S, % S2, . . . due to the influence of inertia and the like, and completely stops at position S. This stop position, that is, the position S where the robot hand 38a actually exists is set at step 7.
is detected in the third storage section 58 of the main memory 58.
It is stored after address ○+1 of C.

In step 8, the state of the hydraulic unit 22 is checked, and when the hydraulic pressure is on, the target position is set as the stop position S of the robot hand 38a, and in step 10 it is checked whether a restart signal is detected. If the oil pressure is off (STP8) or if a restart signal is not detected (STPIO), the process returns to step 7. When the hydraulic pressure is off, the robot (robot hand 38a) is in a free state, and the current position S of the robot hand 38a is always set as the command position. In step 10, when the restart signal is detected, it is checked whether or not the operation is to be stopped (STPII). If not, in step 12, the main processing unit 46 moves the robot hand 38a from the current position S to the return target position E ( Step 5 to the fourth storage unit 58D
The robot hand 38a is moved to the position stored in ) at a speed slower than the normal speed.

After this, the return target position E is the robot hand 38a at the time when the emergency stop signal was detected, as described above.
By returning the robot hand 38a to this position, the robot hand 38a returns to the planned movement path. Thereby, the robot hand 38a can return to the operation at the time when it was brought to an emergency stop in step 13.

The robot hand 38a returns from the stop position S to the return target position E.
If an emergency stop occurs while the robot is returning, the position of the robot hand 38a at the time the emergency stop signal was detected is stored as a new return target position E1 at address P+1 of the fourth memory B58D. The actual stop target position of the arm is stored in the third storage unit 58C, and when the restart signal is detected, the robot hand 38a first returns to the return target position E1 at address P+1, and then returns to the return target position E1 at address P+1.
The address is nested so as to return to the return target position E, and multiple return processing is performed. For example, in FIG. 4, while the robot hand 38a is returning from position S to position E in the order of K1, K2, etc., an emergency stop signal is further detected at position K2, and the robot hand 38a moves back to position K1.
, K2, .
a is returned, and then the robot hand 38a can restart from the return target position E, which was the emergency stop signal detection position, according to the planned movement route.

In the above embodiment, the storage units are described as being divided into the first to fourth storage units 58A to 58D, but the present invention is not limited to this. For example, for the return target positions El and E2, , it goes without saying that the storage units may be combined so that they are stored at addresses N111 and N+2 of the first storage unit 58A, respectively.

[Effects of the Invention] Since the present invention is constructed as described above, it produces the effects described below.

That is, according to the robot control system according to the present invention, when an emergency stop is performed while the robot hand is moving along a planned movement path, and the robot hand deviates from the planned movement path and stops, the emergency stop signal is detected. The fourth position is set as the return target position at the time when the robot hand is moved.
The position where the robot hand actually stopped is stored in the third storage unit as the current position, and the robot hand returns from the current position to the return target position at a speed slower than the normal speed when restarting. Therefore, restarting after an emergency stop can be performed extremely easily and safely.

Further, according to the present invention, even if an emergency stop occurs during the return operation of the robot hand from the stop position at the time of emergency stop to the return target position, the nesting is performed so that the same operation can be repeated and the movement processing can be performed. Since the system is designed so that multiple emergency stops can be easily accommodated.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an assembly robot system to which a robot control system according to an embodiment of the present invention is applied, FIG. 2 is a schematic diagram of a work station, and FIG. 3 is a diagram showing a robot control system according to an embodiment of the present invention. FIG. 4 is a diagram for explaining the movement path of the robot hand, and FIG. 5 is a flowchart for explaining the operation during an emergency stop. 10... Assembly robot system l2... Sequencer 14... Assembly robot 18... Teaching box 20... Robot controller 22... Hydraulic unit 24... Work station 42... I/O processing Section 44... Servo control section 46... Main processing section 54, 56... Dual boat RAM 58... Main memory 58A to 58D... Storage section Current target position

Claims (3)

[Claims] (1) In a robot control system that positions a moving body at a final target position according to a movement path determined by a pre-specified target position and causes the mobile body to perform a predetermined work, the system stores the final target position. a first storage unit that stores the current target position; a third storage unit that stores the current position of the moving body; and a third storage unit that stores the current position of the moving body; a fourth storage unit that stores the position of the moving body at the time when the signal is detected as a return target position, and when a restart signal is detected after an emergency stop, the movement stored in the third storage unit After returning the mobile body from the current position of the body to the return target position stored in the fourth storage unit at a speed slower than the normal movement speed, the mobile body is returned to the final target position stored in the first storage unit. A robot control system characterized by positioning. (2) The control system according to claim 1, wherein the first
Robot control characterized in that the position information of the moving body stored in the storage unit, the second storage unit, the third storage unit, and the fourth storage unit is stored as position data on each orthogonal axis of a three-dimensional space. system. (3) In the control system according to claim 1 or 2,
The mobile body makes an emergency stop, a restart signal is detected,
While moving to the return target position stored in the fourth storage unit,
Furthermore, when an emergency stop signal is detected, the position of the moving body at the time when the emergency stop signal is detected is determined by the fourth
sequentially storing the movable body as a return target position in a storage unit, and sequentially performing operations for returning the movable body from the current position of the movable body stored in the third storage unit to the return target position stored in the fourth storage unit; A robot control system characterized by enabling repeated nesting control.