Force output adjustment in force feedback devices based on user contact

• US 7,965,276 B1
• Filed: 03/01/2001
• Issued: 06/21/2011
• Est. Priority Date: 03/09/2000
• Status: Active Grant

• Current Assignee: Immersion Corporation
• Original Assignee: Immersion Corporation
• Inventors: Braun, Adam C., Moore, David F., Martin, Kenneth M.
• Primary Examiner(s): Nguyen; Kevin M
• Application Number:
  US09/798,872
• Time in Patent Office: 3,764 Days
• Field of Search: 345156-184
• US Class Current: 345/161
• CPC Class Codes: G06F 2203/013 Force feedback applied to a game
• CPC Class Codes: G06F 2203/015 Force feedback applied to a joystick
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user

Abstract

A method and apparatus for adjusting force output from force feedback devices based on user contact with the device. A degree of user contact with a manipulandum of the device is determined by examining the motion of the manipulandum in at least one degree of freedom. A force is output in the degree of freedom of the manipulandum by an actuator of the force feedback device, where a magnitude of the force is adjusted in accordance with the degree of user contact. The force output can be stopped if the user is not contacting the manipulandum, or the forces can be reduced in magnitude if the user has a light contact or reduced grip on the manipulandum. The device can also continue to monitor manipulandum motion to determine when the user is again interacting with the manipulandum and to reapply or increase the magnitude of the forces.

Claims

1. A method comprising:

receiving a sensor signal that relates to a motion of a manipulandum in at least one degree of freedom;

determining a degree of user contact with the manipulandum associated with the received sensor signal; and

outputting a force having a magnitude in the at least one degree of freedom, the force magnitude being associated with the determined degree of user contact;

wherein said determining a degree of user contact includes comparing a motion of the manipulandum with a predicted motion of the manipulandum based on a model of motion of said manipulandum.

2. A method as recited in claim 1, wherein the magnitude of the output force is substantially zero if no user contact with the manipulandum is detected.

3. A method as recited in claim 1 wherein said determining a degree of user contact includes detecting whether a user is contacting the manipulandum.

4. A method as recited in claim 3, wherein the output force is output at a first magnitude when a user is contacting the manipulandum, and is output at a second magnitude when a user is not contacting the manipulandum.

5. A method as recited in claim 1, further comprising changing the force magnitude based on the degree of user contact.

6. A method as recited in claim 1, wherein said determining a degree of user contact includes determining a velocity of the manipulandum in at least one degree of freedom, wherein said force magnitude is adjusted if a change in said velocity is determined to be outside a predetermined range.

7. A method as recited in claim 1, wherein the magnitude of the output force is adjusted if high frequency oscillations of the manipulandum in the at least one degree of freedom are detected.

8. A method as recited in claim 1, wherein the magnitude of the output force is adjusted if a velocity of the manipulandum in the at least one degree of freedom is detected above a predetermined threshold.

9. A method as recited in claim 1, further comprising applying a test force to the manipulandum and examining a test motion of the manipulandum resulting from the test force.

10. A method as recited in claim 9, wherein the test force is applied periodically.

11. A method as recited in claim 1, wherein the force output is based on a host command received from a host computer.

12. An apparatus comprising:

a manipulandum that is moveable in at least one degree of freedom;

a movement-sensor coupled to said manipulandum;

a force-feedback actuator coupled to said manipulandum; and

a processor coupled to said force-feedback actuator and to said movement sensor; and

, a memory coupled to said processor, said memory storing instructions to receive sensor signals that relate to a motion of a manipulandum in at least one degree of freedom, determine a degree of user contact with the manipulandum associated with the received sensor signals, and output a force in the at least one degree of freedom, the force magnitude being associated with the determined degree of user contact;

wherein said determine a degree of user contact includes comparing a motion of the manipulandum with a predicted motion of the manipulandum based on a model of motion of said manipulandum.

13. Processor-executable code comprising:

code to receive a sensor signal that relates to a motion of a manipulandum in at least one degree of freedom;

code to determine a degree of user contact with the manipulandum associated with the received sensor signal; and

code to output a force in the at least one degree of freedom, the force magnitude being associated with the determined degree of user contact;

wherein said code to determine a degree of user contact includes code to compare a motion of the manipulandum with a predicted motion of the manipulandum based on a model of motion of said manipulandum.

14. The processor-executable code of claim 13, further comprising code to output a force of magnitude that is substantially zero if no user contact with the manipulandum is detected.

15. The processor-executable code of claim 13, wherein said code to determine a degree of user contact includes code to determine whether the user is contacting the manipulandum.

16. The processor-executable code of claim 15, wherein said code to output a force includes code to output at a force at a first magnitude when a user is contacting the manipulandum, and code to output a force at a second magnitude when a user is not contacting said manipulandum.

17. The processor-executable code as recited in claim 13, further comprising code to change the force magnitude based on the degree of user contact.

18. The processor-executable code as recited in claim 13, where said code to determine a degree of user contact includes code to determine a velocity of the manipulandum in at least one degree of freedom, and code to adjust the force magnitude if a change in said velocity is determined to be outside a predetermined range.

19. The processor-executable code as recited in claim 13, further comprising code to adjust a magnitude of the output force if high frequency oscillations of the manipulandum are detected.

20. The processor-executable code as recited in claim 13, further comprising code to adjust a magnitude of the output force if a velocity of the manipulandum in said at least one degree of freedom is determined to be above a predetermined threshold.

21. The processor-executable code as recited in claim 13, further comprising code to apply a test force to the manipulandum and code to examine a test motion of the manipulandum resulting from the test force.

22. The processor-executable code as recited in claim 21, wherein the test force is applied periodically.

23. The processor-executable code as recited in claim 13, wherein said force output is based on a host command received from a host computer.