Industrial robot synchronous control method and apparatus

• US 5,254,923 A
• Filed: 07/22/1992
• Issued: 10/19/1993
• Est. Priority Date: 07/24/1991
• Status: Expired due to Fees

• Current Assignee: Nachi-Fujikoshi Corporation
• Original Assignee: Nachi-Fujikoshi Corporation
• Inventors: Kanitani, Kiyoshi
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): Masih, Karen
• Application Number:
  US07/916,717
• Time in Patent Office: 454 Days
• Field of Search: 901/1, 901/8, 318/568.11, 318/568.15, 318/568.12
• US Class Current: 318/568.11
• CPC Class Codes: B25J 9/009 being mechanically linked with one another at their distal ends
• CPC Class Codes: B25J 9/1682 Dual arm manipulator; Coordination of several manipulators
• CPC Class Codes: G05B 2219/34397 Synchronize manipulators and machine by using a reference clock for all
• CPC Class Codes: G05B 2219/34399 Switch between synchronous and asynchronous mode of controllers
• CPC Class Codes: G05B 2219/39132 Robot welds, operates on moving workpiece, moved by other robot
• CPC Class Codes: G05B 2219/39141 Slave program has no taught positions, receives position from master, convert from master
• CPC Class Codes: G05B 2219/39142 Moving time between positions in slave program coordinated online with master
• CPC Class Codes: G05B 2219/45074 Edge treating robot, machine

Abstract

In order to synchronize the operations of at least two industrial robots which can operate independently of each other in accordance with their respective operation programs, the time is obtained which is required for one of the robots serving as the master to move from one working position to the next position at which it operates jointly with the remaining robot. The remaining robot serving as the slave is moved from the position where it exists at present to another position corresponding to said next position, thereby synchronizing the operations of all the robots. An apparatus for such synchronous control comprises a program used to compute with a specified moving speed the interpolation movement due to which each robot is moved between the adjacent working positions and a program used to compute the interpolation movement with a specified moving time. In case of the asynchronous control, the robots move independently in accordance with their respective operation programs. On the other hand, in case of the synchronous control, the interpolation movement of the master robot is decided according to the moving speed specified program, while the interpolation movement of the slave robot is decided according to another program with the moving time of the master robot being specified.

Claims

1. A method of controlling at least two industrial robots with use of a control apparatus which comprises at least one microcomputer used to execute operation programs of respective robots, at least one operation program storage section in which said operation programs are stored, at least one interpolation computing program storage section in which an interpolation computing program used to move each robot from one working position to the next working position is stored, actuator control sections the number of which corresponds to the number of said robots, and one shared memory, wherein said interpolation computing program storage section is provided with means for computing an interpolation movement with a specified moving speed and means for computing the interpolation movement with a specified moving time, said operation programs each contain a master/slave changing information used to designate one of the robots as the master and the remainder as the slave, and a synchronization ON/OFF changing information used to judge whether or not it is necessary to synchronize the robots, the method comprising the steps of changing said two interpolation computer means in accordance with said two changing informations, operating said robots independently of each other when the synchronization is turned OFF about all the robots, performing with the master robot the moving speed specified interpolation movement when the synchronization is turned ON about all the robots, and performing with the slave robot the moving time specified interpolation movement due to which the slave robot is moved in the same time required for the movement of the master robot without making use of the specified moving speed, thereby controlling at least two robots synchronously while performing the interpolation movements.

2. A method according to claim 1, wherein said control apparatus has only one microcomputer, said operation programs each contain a master control program and a slave control program, further comprising the steps of executing said master control program and said slave control program by said one microcomputer through a time-sharing processing, and executing interpolation computing processings of the master and slave robots in accordance with said master control program when the synchronization is turned ON while omitting the interpolation computing processing of said slave control program, thereby reducing the discrepancy in synchronization in case of controlling two robots by one microcomputer.

3. A control method of synchronizing the operations of at least two industrial robots which can operate independently of each other in accordance with their respective operation programs, said method comprising the steps of:

obtaining the time required for one of said robots to move from one working position to the next position at which it operates jointly with the remaining robot; and

synchronizing the operations of all the robots by moving the remaining robot from the position where it exists at present to another position corresponding to said next position in the same time as said required time.

4. A method according to claim 3, wherein the operation program of each robot contains an information used to instruct the synchronization so that the synchronization of said robots is executed in accordance with these informations.

5. A method according to claim 3, further comprising the steps of:

designating one of the robots as the master and the remaining robot as the slave when performing the synchronous control; and

computing said required time about the robot designated as the master

6. A control apparatus used to synchronize the operations of at least two industrial robots which can operate independently of each other in accordance with their respective operation programs, said apparatus comprising;

means for obtaining the time required for one of said robots to move from one working position to the next position at which it operates jointly with the remaining robot; and

means for synchronizing the operations of all the robots by moving the remaining robot from the position where it exists at present to another position corresponding to said next position in the same time as said required time.

7. An apparatus according to claim 6, wherein the operation program of each robot contains an information used to instruct the synchronization so that the synchronization of said robots is executed in accordance with these informations.

8. An apparatus according to claim 7, wherein the operation program of said each robot further contains an information used to designate one of the robots as the master and the remaining robot as the slave in performing the synchronous control, and said required time is computed about the robot designated as the master.

9. An apparatus according to claim 6, further comprising a storage section in which a program used to compute the interpolation movement due to which each robot is moved from a first working position to a second position is stored, said storage section is provided with means for computing the interpolation movement with a specified moving speed and means for computing the interpolation movement with a specified moving time, and said means for synchronizing the operations includes said moving time specified interpolation movement computing means.

10. An apparatus according to claim 8, further comprising one microcomputer means for executing the operation program of each robot, wherein said operation program contains a master control program and a slave control program, said master control program and said slave control program are executed by said one microcomputer means through the time-sharing processing, and the interpolation computing processings of the master and slave robots are executed in accordance with said master control program when the synchronous control is effected while omitting the interpolation computing processing of said slave control program, thereby reducing the discrepancy in synchronization in case of controlling two robots by one microcomputer means.