JPH033786A - Control method for manipulator - Google Patents

Abstract

PURPOSE:To continue work with the use of residual driving part where no abnormality is generated or to retreat so as not to hinder the work of the other manipulator by fixing a driving part where abnormality is generated and changing a control program according to the abnormal state. CONSTITUTION:In the case of abnormality being generated on several joints (driving part) in a manipulator having joints 1 - 5 in (n) pieces, it is detected by a detection circuit 10, an abnormality generating joint is fixed and also a control program is changed by a program preparing circuit 12 according to the abnormal state. Consequently the work can be done by using the residual joints on which no abnormality is generated or it can be retreated so as not to hinder the works of other manipulators.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a control method for a manipulator, and particularly for manipulators in environments where timely repair is difficult, such as deep sea, space, and nuclear reactors. Control Method (Prior Art) Conventionally, control programs for manipulators have been created on the premise that all driving parts, such as joints, function normally. Therefore, in a manipulator having n joints, even if an abnormality occurs in only one joint, all functions of the manipulator are stopped.

(Problems to be Solved by the Invention) In the conventional manipulator control system, if the drive part in which the abnormality has occurred, for example, the joint, is in an environment where it can be repaired, is it possible to eliminate the abnormality and work by repairing it? Items that are controlled by remote control or autopilot, such as deep sea or space applications, or under high temperature or extremely low temperatures.
In manipulators used for work in places unsuitable for humans to work, such as around radioactive materials, if an abnormality occurs in the joint, it is difficult to resolve the abnormality and it is difficult to continue the work.

In actual work, a manipulator with n joints does not have to operate all of the n joints, but rather fixes the joint where an abnormality has occurred and uses the remaining joints. Some work is possible.

In addition, in a transport system consisting of multiple transport robots with manipulators, if an abnormality occurs in the joint of the manipulator of one transport robot, the joint where the abnormality has occurred is fixed, making it difficult to perform operations using the remaining joints. If so, it is necessary to evacuate the robot so that it does not interfere with the work of the manipulators of other robots.

The present invention has been made in view of the above-mentioned problems, and even if a manipulator having a plurality of drive parts, such as joints, malfunctions in some of the joints, the remaining joints can be used to perform work or retreat posture. The purpose of this invention is to provide a manipulator control method that can take the following steps.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a manipulator that has a plurality of drive parts and is controlled by a control program created in advance. an abnormality detecting means for detecting a mechanical system abnormality and a control system abnormality in a part; a driving part locking means for fixing a driving part in which an abnormality is detected by the abnormality detecting means; and program changing means for changing the control program for the manipulator depending on the abnormal state of the part.

(Function) In the manipulator control method of the present invention, by adopting a two-state configuration, when an abnormality occurs in some of the joints in a manipulator having n joints, the joint in which the abnormality has occurred is It is fixed and the control program is changed depending on the abnormal condition.

As a result, it is possible to work using the remaining joints in which no abnormality has occurred, or to evacuate the joints so as not to interfere with the work of other manipulators.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a schematic diagram of the manipulator, and in the figure, numerals 5 to 5 are joints 1 to 5, which are drive parts that drive the arms of the manipulator, and the 5th joint is the tip of the joint.
A hand 6 is provided at the end of the joint 5, and each joint has a built-in motor (not shown) for driving the arm, an encoder, and a joint lock mechanism for fixing the joint in the event of an abnormality. There is.

As the joint lock mechanism, there is a mechanism that locks the motor by turning off the power, for example.

The manipulator is controlled by a control device 7, and the control device 7 reads programs from a RAM 8, which is a storage device in which control programs are stored, as needed to control the manipulator.

The joint confirmation signal consisting of the joint bending angle signal output from the encoder built in each joint I and the speed signal output from the motor is bus 9.
The signal is input to the abnormality detection circuit 10 via. Furthermore, a measured attitude signal obtained by a monitoring stereo camera 11.11 that monitors the attitude of the manipulator and a theoretical attitude signal outputted from the control device 7 are input to this abnormality detection circuit. - The abnormality detection circuit 10 includes a mechanical system abnormality detection section that detects abnormalities in the mechanical system such as abnormal rotation of a motor, a control system abnormality detection section that detects abnormalities in the control system such as the bending angle of the joint and the posture of the manipulator; It consists of an attitude detection section that three-dimensionally recognizes the attitude of the manipulator based on the measured attitude signal.

1. When an abnormality in the mechanical system or an abnormality in the control system is detected in the abnormality detection circuit 10, an abnormality detection signal is sent from the abnormality detection circuit 10 to the control unit 7, and an abnormality is generated in the program creation circuit 12. Abnormal data for each joint part is output.

The program creation circuit 12 creates a new control program based on the abnormality data input from the abnormality detection circuit 1o, outputs this new program to the RAM 8, and outputs a program creation end signal to the abnormality detection circuit 10.

Next, a control method for the manipulator will be explained using flowchart 1 shown in FIGS. 1 and 2 showing the operation of the manipulator in FIG. 1.

First, when a command to move the part P from point A to point B is input to the control device 7 from an operation console (not shown) or a host I/computer, the control device 7 moves each of the first to fifth joints 1.2, 2. 3. You will be instructed to start work on 4.5. (Step Sl).

When instructed to start work, a join I/confirmation signal is input from each of the first to fifth joins l-1, 2, 3, 4, and 5 to the abnormality detection circuit 10 via the bus 9. Based on the joint confirmation signal thus obtained, the abnormality detection circuit 10 detects whether or not there is an abnormality in the mechanical system due to abnormal rotation of the motor in a mechanical system abnormality detection section. In addition, the control system abnormality detection unit uses the joint confirmation signal regarding the bending angle of the joint and the 7Illll fixed attitude signal inputted from the monitoring stereo camera 1111, and the posture of the manipulator that is three-dimensionally recognized by the attitude detection unit. The presence or absence of an abnormality in the control system is detected by comparing it with the theoretical attitude signal input from 7.

(Steps S2, S3).

In step S2 and step S3, if there is no abnormality in the joint, the control device 7
8, the fourth joint 4 is operated as shown by the dotted line, and the part P is moved from point A to point B.

(Step 811).

Next, for example, when an abnormality occurs in which the motor of the fourth joint 4 stops rotating and the fourth joint 4 does not operate, the abnormality detection circuit 10 detects that the joint confirmation signal from the fourth joint has stopped changing. Detected by the mechanical abnormality detection section. When an abnormality is detected, an abnormality detection signal is output from the abnormality detection circuit 10 to the control device 7,
The control device 7 issues a work stop command to the manipulator to temporarily stop the work. At the same time, a command is issued from the control device 7 to the joint i/lock mechanism of the fourth joint, where the abnormality has occurred, to fix the fourth joint, and the fourth joint is fixed. (Steps S4, S5).

Further, from the abnormality detection circuit 10 to the program creation circuit 12
The program creation circuit 2 creates a coordinate conversion program that can perform work with the fourth joint 4 fixed based on the input abnormal data, and uses this to create a new control program. create. When the created new control program is written into the RAM 8, the program creation circuit 12 outputs a program creation end signal to the abnormality detection circuit 10. (Steps S6, S7, S8
).

Next, when the abnormality detection circuit 10 instructs the control device 7 to cancel the work-time stoppage and restart the work, the control device 7 first instructs the manipulator to cancel the work-time stoppage. (Step S9).

Then, the control device 7 searches whether or not there is a new control program written in the RAM 8j- for the operation to be performed for restarting.

If this work is on a new control program, the work program is read and the fourth joint 4 is kept fixed and moved as shown by the two-dot chain line to move the part P from point A to point B. (Step SIO, S11).

If there is no such manipulator, the control device 7 determines that it is impossible to continue the work, and changes the command to the manipulator to take a retracted posture so as not to interfere with other manipulators. (Step 512).

It is especially necessary for transfer robots each having a manipulator to take such a retreat posture.

In the first embodiment, an abnormality in the mechanical system was explained, but in the case of an abnormality in the control system, a joint confirmation signal manually input from the encoder of each joint and a monitoring stereo camera] 1. , I1, the theoretical attitude signal inputted from the control device 7 and the abnormality detection circuit 1.
By comparing the values with 0 and 0, it is detected whether or not an abnormality has occurred in the control system. Operations other than abnormality detection in the control system are the same as those for abnormality in mechanical system 0 above.

It should be noted that the present invention is not limited to the embodiments shown in FIGS. 1 and 2 above, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As described in detail, according to the manipulator control method of the present invention, when an abnormality occurs in the drive section, the drive section in which the abnormality has occurred is fixed, and the control system is adjusted according to the abnormal state. Since the control program is changed, it is possible to continue work using the remaining drive parts that have not experienced an abnormality, or to evacuate them so that they do not interfere with the work of other manipulators.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the manipulator of the present invention, and FIG. 2 is a flowchart showing the operation of the manipulator shown in FIG. 1.2, 3, 4.5... Drive section (joint), 8.
・RAM, 10... Abnormality detection circuit, 1 code program creation circuit

Claims (1)

[Claims] In a manipulator having a plurality of drive parts and controlled by a control program created in advance, an abnormality detection means detects a mechanical system abnormality and a control system abnormality of the plurality of drive parts, and an abnormality is detected by the abnormality detection means. and a program changing means for changing the control program of the manipulator in accordance with an abnormal state of the driving part whose abnormality is detected by the abnormality detecting means. Manipulator control method.