System for commanding a robot

• US 9,254,567 B2
• Filed: 01/27/2014
• Issued: 02/09/2016
• Est. Priority Date: 07/27/2011
• Status: Expired due to Fees

• Current Assignee: ABB Schweiz AG (ABB Limited)
• Original Assignee: ABB Technology AG (ABB Limited)
• Inventors: Dai, Fan, Becker, Oliver
• Primary Examiner(s): Sample, Jonathan L
• Application Number:
  US14/165,161
• Publication Number:
  US 20140142754A1
• Time in Patent Office: 743 Days
• US Class Current: 1/1
• CPC Class Codes: B25J 9/16 Programme controls programme controls in general G05B19/00, e.g. numerical pogramme controls G05B19/18; recording or playback systems G05B19/42
• CPC Class Codes: G05B 19/056 Programming the PLC

Abstract

A system and method for commanding a robot by a programmable logic controller are disclosed. The system can include a programmable logic controller, at least two function blocks with at least one input for triggering an execution of a PLC function and at least one output indicating status of a function block. Each function block corresponds to a movement segment of a movement path of a robot to be commanded. A command queue can store and send orchestrated robot commands to the robot. Backwards motion of the robot can be performed by stopping execution of not yet executed robot commands for forward motion, and sequentially resending at least one executed robot command stored in the command queue in a contrawise sequence.

Claims

1. A system for commanding a robot by a programmable logic controller, the system comprising:

a programmable logic controller;

at least two function blocks with at least one respective input configured to trigger an execution of a programmable logic controller (PLC) function block and at least one respective output configured to indicate a status of the respective function block, and wherein each function block corresponds to a movement segment of a programmed movement path of a robot to be commanded;

a robot controller interface configured to orchestrate a PLC function block currently in execution into a robot command;

a command queue configured to store the respective orchestrated robot commands and for sending them sequentially to the robot for sequentially execution, wherein the command queue is configured to keep at least a last executed robot command within a memory within the command queue, and wherein the command queue is configured to store information, which includes whether a robot command has not yet been executed, is currently in execution or has been executed;

wherein the system is configured to control a backwards motion of the robot along a movement path by stopping the execution of not yet executed robot commands for forward motion and by sequentially resending the at least one executed robot command stored in the command queue in a contrawise sequence to the robot via the programmable logic controller; and

the system is foreseen to delete all not yet executed robot commands for forward motion from the command queue in case of a backward motion.

2. The system according to claim 1, comprising:

an operation mode for backward motion.

3. The system according to claim 1, wherein an executed robot command is acknowledged before resending the command to the robot.

4. The system according to claim 1, wherein in combination with a robot which comprises:

an internal backward motion functionality, which is configured to address backwards motion along a path of an incompletely executed movement segment.

5. The system according to claim 1, wherein a request for backwards motion is only executable when at least one executed robot command is available within the command queue which has not yet been resent to the robot.

6. The system according to claim 1, wherein the programmable logic controller is configured to:

swap coordinate data of a starting and/or an end point of a movement segment represented by an already executed robot command before resending the command to the robot.

7. The system according to claim 6, wherein the coordinate data of the starting point of the movement segment are represented by coordinate data of the end point of a preceding movement segment.

8. The system according to claim 1, comprising:

a shifting register or a ring buffer, wherein the command queue is organized in the shifting register or the ring buffer, such that an oldest robot command is overwritten by a newest robot command.

9. The system according to claim 1, wherein the programmable logic controller is configured to delete an executed robot command within the command queue after resending.

10. The system according to claim 1, comprising:

a common data processing device, wherein the programmable logic controller and a robot controller for the robot to be commanded are integrated within the common data processing device.

11. A method for commanding a robot using a system including a programmable logic controller, at least two function blocks with at least one respective input configured to trigger an execution of a programmable logic controller (PLC) function and at least one respective output configured to indicate a status of a respective function block, and wherein each function block corresponds to a programmed movement segment of a movement path of a robot to be commanded, a robot controller interface configured to orchestrate a PLC function block currently in execution into a robot command, and a command queue configured to store respective orchestrated robot commands and for sending them sequentially to the robot for sequentially execution, the method comprising:

temporarily switching the system into an operational mode;

sequentially orchestrating robot commands into the command queue;

sequentially sending the robot commands to the robot;

sequentially executing the robot commands by the robot;

stopping the orchestrating, sending and execution of the robot commands;

switching the system into a backwards motion mode;

temporarily deleting the orchestrated, but not yet executed robot commands within the command queue;

automatically identifying a last executed robot command within the command queue;

sequentially resending at least a part of the executed robot commands stored in the command queue in a contrawise sequence to the robot via the programmable logic controller;

temporarily acknowledging, before resending, a robot command;

backwards executing a robot command by the robot;

temporarily deleting the executed robot command, which has been resent, from the command queue;

switching the system back to the operational mode; and

restarting normal operational mode from the actual robot position.

12. The method of claim 11, comprising:

configuring the command queue to keep at least a last executed robot command within a memory within the command queue.

13. The method of claim 12, comprising:

configuring the command queue to store information, which includes whether a robot command has not yet been executed, is currently in execution or has been executed.

14. The method of claim 13, comprising:

configuring the system to control backwards motion of the robot along a movement path by stopping execution of not yet executed robot commands for forward motion.