Force and torque converter

• US 5,591,924 A
• Filed: 04/23/1993
• Issued: 01/07/1997
• Est. Priority Date: 12/18/1985
• Status: Expired due to Term

• Current Assignee: Labtec, Inc. (Logitech International SA)
• Original Assignee: Spacetec IMC Corporation
• Inventors: Hilton, John A.
• Primary Examiner(s): Chilcot, Richard
• Assistant Examiner(s): Dougherty, Elizabeth L.
• Application Number:
  US08/052,377
• Time in Patent Office: 1,355 Days
• Field of Search: 73/862.042, 73/862.043, 73/862.05, 73/862.041, 74/471 XY, 250/221
• US Class Current: 73/862.043
• CPC Class Codes: G01L 1/248 using infrared G01L1/241, G01L1/242 take precedence
• CPC Class Codes: G01L 5/1627 of strain gauges using piezoresistors G01L5/162
• CPC Class Codes: G01L 5/166 using photoelectric means
• CPC Class Codes: G01L 5/223 to joystick controls
• CPC Class Codes: G06F 3/03543 Mice or pucks G06F3/03541 takes precedence
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry
• CPC Class Codes: H01H 2239/052 Strain gauge
• CPC Class Codes: Y10T 74/20201 Control moves in two planes

Abstract

A force and torque converter is provided which provides an electronic representation of a planarly applied force and a torque applied about an axis that is orthogonal to the plane. The converter includes a base, an actuating member which is relatively displaced in response to the applied torque and force, resilient mechanisms to provide a restoring force and torque to the actuating member, and sensing mechanisms to sense the applied torque and force and generate an electronic representation thereof. The electronic representation is characterized by a sensitivity curve in which relatively small applied forces and torques result in a relatively low scale factor and where for a range of small applied forces and torques the relation of scale factor with respect to applied torque and force has a relatively low derivative. Further, for a range of larger applied forces and torques, the sensitivity curve has a relatively large scale factor and a relatively large derivative. In one embodiment, the sensitivity curve is implemented by a processing mechanism which includes a microprocessor and firmware.

Claims

1. An apparatus for providing an electronic representation in response to force being applied to said apparatus, the apparatus comprising:

a base;

an actuating member for receiving said applied force;

resilient means for generally supporting the actuating member from the base, and for providing restoring force to said actuating member; and

sensing means responsive to movement of the actuating member relative to said base for providing said electronic representation, the electronic representation being representative of the applied force in a direct relationship which is defined by a sensitivity curve relating the electronic representation to the applied force, said sensitivity curve having a derivative in a first region of the curve that is relatively small compared to a derivative in a second region of the curve and further having a derivative in a third region of the curve that is relatively small compared to said derivative in a second region, said first region corresponding to a range of small applied forces, said second region corresponding to a range of intermediate applied forces, and said third region corresponding to high applied forces.

2. An apparatus as set forth in claim 1, wherein said resilient means provides restoring force to return the actuating member to an original position.

3. An apparatus as set forth in claim 1, wherein the sensitivity curve further includes a null region corresponding to a range of very small applied forces and having a negligible derivative in said null region, and wherein for applied forces within said range of very small applied forces the electronic representation indicates that no force has been applied.

4. An apparatus as set forth in claim 1, wherein the electronic representation is also representative of a torque applied to the apparatus in a direct relationship characterized by a second sensitivity curve relating the electronic representation to the applied torque, said second sensitivity curve having a derivative in a first region of the second curve that is relatively small compared to a derivative in a second region of the second curve and further having a derivative in a third region of the second curve that is relatively small compared to said derivative in a second region of the second curve, said first region of the second curve corresponding to a range of small applied torques, said second region of the second curve corresponding to a range of intermediate applied torques, said third region of the second curve corresponding to high applied torques.

5. An apparatus as set forth in claim 4, wherein the second curve further includes a null region corresponding to a range of very small applied torques and having a negligible derivative in said null region of said second curve, and wherein for applied torques within said range of very small applied torques the electronic representation indicates that no torque has been applied.

6. An apparatus as set forth in claim 1, further comprising inhibiting means for limiting movement of the actuating member to predetermined desirable directions and to predetermined limited extension.

7. An apparatus for providing an electronic representation in response to force being applied in a plane and torque being applied about an axis that is orthogonal to said plane, comprising:

a base;

an actuating member for receiving said applied force and said applied torque, said actuating member being planarly displaced relative to said base in direct relationship to the applied force and being angularly displaced about the axis and relative to said base in direct relationship to the applied torque;

resilient means for generally supporting the actuating member from the base, and for providing restoring force and restoring torque to the actuating member; and

sensing means, responsive to movement of said actuating member relative to said base, for providing said electronic representation, the electronic representation being representative of the applied force and the applied torque according to a non-linear sensitivity curve.

8. An apparatus as set forth in claim 7 wherein the sensing means includes a photo-masking means for masking light and a photo-optical sensing means for emitting light and detecting light.

9. An apparatus as set forth in claim 8 wherein photo-optical sensing means is mounted on the base and the photo-masking means depends from the actuating member, the photo-masking means masking light emitted by the photo-optical sensing means in a direct relationship to the planar displacement and the angular displacement of the actuating member.

10. An apparatus as set forth in claim 7, wherein the resilient means provides limited planar displacement with negligible friction and limited angular displacement with negligible friction.

11. An apparatus as set forth in claim 7, wherein said resilient means provides restoring force to return the actuating member to an original position.

12. An apparatus as set forth in claim 7, further comprising inhibiting means for limiting movement of the actuating member to predetermined desirable directions and to predetermined limited extension.

13. An apparatus as set forth in claim 7, wherein the actuating member includes a grip that is constructed and arranged to receive said applied force and said applied torque by a human hand.

14. An apparatus for providing an electronic representation in response to force being applied in a plane and torque being applied about an axis that is orthogonal to said plane, comprising:

a base;

an actuating member for receiving said applied force and said applied torque, said actuating member being planarly displaced relative to said base in direct relationship to the applied force and being angularly displaced about the axis and relative to said base in direct relationship to the applied torque;

resilient means for generally supporting the actuating member from the base, and for providing restoring force and restoring torque to the actuating member; and

sensing means responsive to movement of said actuating member relative to said base for providing said electronic representation, the electronic representation being representative of the applied force and the applied torque in a direct relationship, wherein the electronic representation is representative of the applied force in a direct relationship which is defined by a sensitivity curve relating the electronic representation to the applied force, said sensitivity curve having a derivative in a first region of the curve that is relatively small compared to a derivative in a second region of the curve and further having a derivative in a third region of the curve that is relatively small compared to said derivative in said second region, said first region corresponding to a range of small applied forces, said second region corresponding to a range of intermediate applied forces, and said third region corresponding to high applied forces.

15. An apparatus as set forth in claim 14, wherein the sensitivity curve further includes a null region corresponding to a range of very small applied forces and having a negligible derivative, and wherein for applied forces within said range of very small applied forces the electronic representation indicates that no force has been applied.

16. An apparatus as set forth in claim 15, wherein the electronic representation is also representative of the applied torque in a direct relationship characterized by a second sensitivity curve relating the electronic representation to the applied torque, said second sensitivity curve having a derivative in a first region of the second curve that is relatively small compared to a derivative in a second region of the second curve and further having a derivative in a third region of the second curve that is relatively small compared to said derivative in a second region of the second curve, said first region of the second curve corresponding to a range of small applied torques, said second region of the second curve corresponding to a range of intermediate applied torques, said third region of the second curve corresponding to high applied torques.

17. An apparatus as set forth in claim 16, wherein the second curve further includes a null region corresponding to a range of very small applied torques and having a negligible derivative, and wherein for applied torques within said range of very small applied torques the electronic representation indicates that no torque has been applied.

18. An apparatus for providing an electronic representation in response to force being applied in a plane and torque being applied about an axis that is orthogonal to said plane comprising:

a base;

an actuating member for receiving said applied force and said applied torque, said actuating member being planarly displaced relative to said base in direct relationship to the applied force and being angularly displaced about the axis and relative to said base in direct relationship to the applied torque;

resilient means for generally supporting the actuating member from the base, and for providing restoring force and restoring torque to the actuating member;

sensing means responsive to movement of said actuating member relative to said base for providing said electronic representation, the electronic representation being representative of the applied force and the applied torque in a direct relationship; and

processing means for receiving said electronic representation and for providing output data wherein said output data is representative of the applied force in a direct relationship which is defined by a sensitivity curve relating the output data to the applied force, said sensitivity curve having a derivative in a first region of the curve that is relatively small compared to a derivative in a second region of the curve and further having a derivative in a third region of the curve that is relatively small compared to said derivative in said second region, said first region corresponding to a range of small applied forces, said second region corresponding to a range of intermediate applied forces, and said third region corresponding to high applied forces.

19. An apparatus as set forth in claim 18, wherein said electronic representation is analog and wherein said output data is digital.

20. An apparatus as set forth in claim 19, wherein said processing means includes an A/D converter for receiving said electronic representation, and providing A/D data utilizing a dual-slope conversion technique.

21. An apparatus as set forth in claim 20, wherein said processing means further includes a microprocessor that receives the A/D data, and provides the output data according to user customized sensitivity characteristics.

22. An apparatus as set forth in claim 18, wherein the sensitivity curve further includes a null region corresponding to a range of very small applied forces and having a negligible derivative, and wherein for applied forces within said range of very small applied forces the output data indicates that no force has been applied.

23. An apparatus as set forth in claim 22, wherein the output data is also representative of the applied torque in a direct relationship characterized by a second sensitivity curve relating the output data to the applied torque, said second sensitivity curve being continuous and having a derivative in a first region of the second curve that is relatively small compared to a derivative in a second region of the second curve and further having a derivative in a third region of the second curve that is relatively small compared to said derivative in a second region of the second curve, said first region of the second curve corresponding to a range of small applied torques, said second region of the second curve corresponding to a range of intermediate applied torques, said third region of the second curve corresponding to high applied torques.

24. An apparatus as set forth in claim 23, wherein the second curve further includes a null region corresponding to a range of very small applied torques and having a negligible derivative, and wherein for applied torques within said range of very small applied torques the output data indicates that no torque has been applied.

25. An apparatus for providing an electronic representation in response to force being applied in a plane and torque being applied about an axis that is orthogonal to said plane, comprising:

a base;

an actuating member for receiving said applied force and said applied torque, said actuating member being planarly displaced relative to said base in direct relationship to the applied force and being angularly displaced about the axis and relative to said base in direct relationship to the applied torque, said actuating member constructed to be responsive only to said planarly applied force and said axially applied torque;

resilient means for generally supporting the actuating member from the base, and for providing restoring force and restoring torque to the actuating member; and

sensing means, responsive to movement of said actuating member relative to said base, for providing said electronic representation, the electronic representation being representative of the applied force and the applied torque according to a non-linear sensitivity curve.