Method and apparatus for compensating for position slip in interface devices

• US 20050088408A1
• Filed: 11/23/2004
• Published: 04/28/2005
• Est. Priority Date: 05/11/1999
• Status: Active Grant

• Current Assignee: Immersion Corporation
• Original Assignee: Immersion Corporation
• Inventors: Martin, Kenneth M., Schena, Bruce M., Braun, Adam C., Tierling, Kollin M.
• Granted Patent: US 7,447,604 B2
• Time in Patent Office: Days
• US Class Current: 345/156
• CPC Class Codes: A63F 2300/1018 Calibration; Key and button assignment
• CPC Class Codes: A63F 2300/1037 being specially adapted for converting control signals received from the game device into a haptic signal, e.g. using force feedback
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user

Abstract

Method and apparatus for compensating for position slip in interface devices that may occur between a manipulandum and a sensor of the device due to a mechanical transmission. A device position delta is determined from a sensed position of a manipulandum of an interface device. It is determined if position slip has occurred caused by a change in position of the manipulandum that was not sensed by a sensor of the interface device, typically caused by a mechanical transmission between sensor and manipulandum. If position slip has occurred, an error in the sensed position caused by the position slip is corrected by adjusting the sensed position to take into account the position slip. The adjusted position delta is used as the position of the manipulandum and the display of objects controlled by the interface device are accordingly compensated.

Claims

1. A method comprising:

determining a device position delta from a sensed position of a manipulandum of an interface device in a degree of freedom, said position delta indicating a change in an actual position of said manipulandum;

determining if a position slip has occurred in a position sensing system, said position slip caused by a change in position of said manipulandum that was not sensed by a sensor of said interface device; and

correcting an error in said sensed position caused by said position slip by adjusting said sensed position to take into account said position slip, and using said adjusted position as said actual position of said manipulandum.

2. A method as recited in claim 1 wherein said determining if said position slip has occurred comprises checking a reference signal from a reference sensor coupled to said interface device, said reference sensor detecting a position of a reference location of said manipulandum.

3. A method as recited in claim 1 further comprising determining a computation value from said device position delta, and outputting said computation value.

4. A method as recited in claim 3 further comprising disregarding said position slip when determining said computation value.

6. A method as recited in claim 1 further comprising performing said determining a device position, said determining if a position slip has occurred, and said correcting an error over a plurality of iterations, and adjusting said sensed position by an amount which gradually reduces said error in said sensed position over said plurality of iterations.

7. A method as recited in claim 1 further comprising using said sensed position of said manipulandum as said actual position of said manipulandum is not performed if said manipulandum is not moving in said degree of freedom.

8. A method as recited in claim 1 wherein said position slip comprises slip caused by a mechanical transmission coupled between said sensor and said manipulandum.

10. A method as recited in claim 3 further comprising modifying said computation value to compensate for an offset between said device position and a screen position of an object displayed by a host computer.

11. A method as recited in claim 3 further comprising modifying said computation value to allow object displayed by said host computer to continue moving after said manipulandum has reached a limit to a workspace of said manipulandum in a direction corresponding to a direction of said manipulandum into said limit.

5. A method as recited in claim 43 further comprising determining a force having a magnitude and a direction at least partially based on said computation value, and outputting said force with an actuator disposed within said interface device.

9. A method as recited in claim 48 wherein said mechanical transmission comprises a drive selected from the group consisting of a gear drive, a belt drive, and a capstan drive.

12. A device comprising:

a manipulandum movable in at least one degree of freedom;

a position sensor operative to detect a position of said manipulandum in at least one of said degrees of freedom;

a mechanical transmission coupled between said manipulandum and said position sensor; and

a reference sensor operative to detect the motion of at least one reference location of said manipulandum.

13. A device as recited in claim 12 wherein said mechanical transmission comprises a gear drive.

14. A device as recited in claim 12 wherein said mechanical transmission in comprises a belt drive.

15. A device as recited in claim 12 wherein said position sensor is comprises a relative digital encoder.

16. A device as recited in claim 12 wherein at least one of said reference locations comprises a physical edge to a member, and wherein said reference sensor comprises an optical sensor operable to detects a passage of said physical edge through an transmitted beam.

17. A device as recited in claim 12 wherein said reference sensor is operable to provides a rising signal edge or a falling signal edge in said reference signal.

18. A device as recited in claim 12 further comprising a local microprocessor, said local microprocessor operable to receive said reference signal and operable to adjust said detected position of said manipulandum if said position slip has occurred.

19. A device as recited in claim 18 wherein said local microprocessor is operable to determines a computation value from a position delta determined from said position, wherein adjusting said computation value is adjusted if said position slip has occurred, said computation value.

20. A method comprising:

enabling a determination of a device position delta from a sensed position of a manipulandum of an interface device in a degree of freedom, said position delta indicating a change in an actual position of said manipulandum;

enabling a determination of whether a position slip has occurred in said position sensing system, said position slip caused by a change in position of said manipulandum that was not sensed by a sensor of said interface device; and

enabling a correction of an error in said sensed position caused by said position slip by adjusting said sensed position to take into account said position slip, and enabling said adjusted position be provided as said actual position of said manipulandum.

21. A method as recited in claim 20 wherein said determining if said position slip has occurred comprises checking a reference signal from a reference sensor coupled to said interface device, said reference sensor operable to detect a position of a reference location of to said manipulandum.

22. A method as recited in claim 21 further comprising performing said determining a device position, said determining if a position slip has occurred, and said correcting an error over a plurality of iterations, and adjusting said sensed position by an amount which gradually reduces said error in said sensed position over said plurality of iterations.

23. A method as recited in claim 20 wherein said position slip is comprises a slip caused by a mechanical transmission coupled between said sensor and said manipulandum.