Contact force limiting with haptic feedback for a tele-operated robot

Patent metadata

Field	Value
Publication number	US-9849595-B2
Application number	US-201615016578-A
Country	US
Kind code	B2
Filing date	Feb 5, 2016
Priority date	Feb 6, 2015
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

One exemplary embodiment is a system comprising an operator input device structured to move in response to operator-applied force and to selectably output feedback force to the operator. A first computing system is structured to receive input from the operator input device and provide an output. A second computing system is structured to receive the output and provide a robot control command subject to a force constraint. An industrial robot system is in operative communication with the second computing system and comprises a robotic arm structured to move in response to the command. The second computing system is structured process the output to impose a force constraint using a dual threshold hysteresis control. The first computing system is structured to apply a feedback force to the operator input device correlated to force associated with the industrial robot system.

First claim

The invention claimed is:

1. A system comprising:
an operator input device structured to move in response to operator-applied force and to selectably output feedback force to the operator;
a first computing system structured to receive input from the operator input device indicating position or movement of the operator input device, process the received input, and provide a resulting output to a communication link;
a second computing system structured to receive the output from the communication link, process the output to provide a robot control command subject to a force constraint, and output the command; and
an industrial robot system in operative communication with the second computing system, the industrial robot system comprising a robotic arm structured to move in response to the command, a tool operatively coupled with the robotic arm, and feedback device structured to provide feedback to the second computing system from which force encountered by the tool may be determined;
wherein the second computing system is structured to process the output to impose force constraint using a dual threshold hysteresis control structured to activate a force limit if the output exceeds a first threshold and to deactivate the force limit if the output is below a second threshold, the second threshold being below the first threshold, and the first computing system is structured to receive the feedback from the second computing system via the communication link, process the feedback to compute a feedback force, and output a feedback force command effective to cause the input device to apply the feedback force to the operator.

2. The system of claim 1 wherein the force constraint is implemented as a limit on speed.

3. The system of claim 1 wherein the feedback force is calculated as a value equal to the difference between a commanded position of the tool and an actual position of the tool multiplied by a constant.

4. The system of claim 3 wherein the first computing device is structured to perform one or both of coordinate transformation and scaling on the calculated feedback force.

5. The system of claim 1 wherein the feedback force is calculated as a value equal to the difference between a commanded velocity of the tool and an actual velocity of the tool multiplied by a constant.

6. The system of claim 5 wherein the first computing device is structured to perform one or both of coordinate transformation and scaling on the feedback information utilized as input to calculate the feedback force.

7. The system of claim 1 wherein the first computing system is structured to process the received input by performing one or both of a coordinate transformation and a scaling operation.

8. The system of claim 1 wherein the feedback force is calculated based upon a force measurement provided as the feedback from the industrial robot system to the second computing system.

9. A method of operating an industrial robotic system including a robotic arm and a tool operatively coupled to the robotic arm, the method comprising:
operating an operator input device structured to move in response to operator-applied force and to selectably output feedback force to the operator;
receiving, with a first computing system, input from the operator input control device indicating position or movement of the operator input device;
processing the received input with the first computing system;
transmitting an output from processing the received input to a second computing system;
processing, with the second computing system, the output to generate a robot control command subject to a force constraint, the force constraint being imposed using a dual threshold hysteresis control structured to activate a force limit if the output exceeds a first threshold and to deactivate the force limit if the output is below a second threshold, the second threshold being below the first threshold;
transmitting the robot control command to the industrial robotic system;
operating the industrial robotic system using the robot control command;
receiving, with the first computing system, feedback from the industrial robotic system indicating force encountered by the tool;
processing, with the first computing system, the feedback to compute a feedback force;
outputting, with the second computing system, a feedback force command to the operator input device; and
applying the feedback force to the operator in response to the feedback force command.

10. The method of claim 9 wherein the feedback force is haptic feedback.

11. The method of claim 10 wherein a magnitude of the haptic feedback is proportional to a magnitude of the feedback from the industrial robotic system subject to a force limit which indicates to the operator that a hard limit on robotic operation has been reached.

12. The method of claim 9 wherein the feedback force is calculated as a value equal to the difference between a commanded velocity of the tool and an actual velocity of the tool multiplied by a constant.

13. The method of claim 9 wherein processing the received input includes performing one or both of a coordinate transformation and a scaling operation.

14. The method of claim 9 comprising measuring the feedback using a plurality of sensors including at least two of a position sensor, a proximity sensors, a camera, a microphone and a force sensor.

15. A control system for a remote industrial robot system including a robotic arm structured to move in response to a robot control command, a tool operatively coupled with the robotic arm, and feedback device structured to provide feedback from which force encountered by the tool may be determined, the control system comprising:
an operator input device structured to move in response to operator-applied force and to selectably output feedback force to the operator; and
a computing system structured to
receive input from the operator input device indicating position or movement of the operator input device,
process the received input to provide the robot control command subject to a force constraint, the force constraint being imposed using a dual threshold hysteresis control structured to activate a force limit if the output exceeds a first threshold and to deactivate the force limit if the output is below a second threshold, the second threshold being below the first threshold,
output the command to the industrial robot system,
receive the feedback from the feedback device,
calculate a feedback force using the feedback, and
output a feedback force command effective to cause the input device to apply the feedback force to the operator,

wherein the computing system comprises a local computing system in communication with the operator input device and a remote computing system in communication with the industrial robot system, and
wherein the local computing system is in communication with the remote computing system by way of a communication link.

16. The system of claim 15 wherein the force constraint is implemented as a limit on velocity.

17. The system of claim 1 wherein the feedback force is calculated as a value equal to the difference between a commanded position or velocity of the tool and an actual position or velocity of the tool multiplied by a constant, and wherein the local first computing device is structured to perform one or both of coordinate transformation and scaling on the calculated feedback force.

18. The computing device of claim 15 wherein the feedback device is a six-axis force/torque sensor.

19. The system of claim

Assignees

• Abb Schweiz Ag

Inventors

• Wang Jianjun
• Fuhlbrigge Thomas A
• Zhang Biao

Classifications

• Y10S901/04

  Manual lead through · CPC title

• G06F2203/014

  Force feedback applied to GUI · CPC title

• G05B2219/37396

  Tactile feedback, operator feels reaction, force reflection · CPC title

• G06F3/016

  Input arrangements with force or tactile feedback as computer generated output to the user · CPC title

• B25J13/025 Primary

  comprising haptic means · CPC title