Three degree of freedom mechanism for input devices

• US 6,580,418 B1
• Filed: 02/29/2000
• Issued: 06/17/2003
• Est. Priority Date: 02/29/2000
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Grome, Donald C., Nielsen, Kurt T.
• Primary Examiner(s): Saras, Steven
• Assistant Examiner(s): Anyaso, Uchendu O.
• Application Number:
  US09/515,967
• Time in Patent Office: 1,204 Days
• Field of Search: 345/161, 345/162, 345/163-167
• US Class Current: 345/161
• CPC Class Codes: A63F 13/21 characterised by their sensors, purposes or types
• CPC Class Codes: A63F 13/22 Setup operations, e.g. calibration, key configuration or button assignment
• CPC Class Codes: A63F 13/24 Constructional details thereof, e.g. game controllers with detachable joystick handles
• CPC Class Codes: G05G 2009/04774 with additional switches or sensors on the handle
• CPC Class Codes: G05G 2009/04777 with additional push or pull action on the handle
• CPC Class Codes: G05G 2009/04781 with additional rotation of the controlling member
• CPC Class Codes: G05G 9/047 the controlling member being movable by hand about orthogonal axes, e.g. joysticks for switches H01H25/04

Abstract

A joystick produces a control input signal in response to a pivotal displacement of a control handle about any of a plurality of axes. Corrected signals for each of orthogonal “X” and “Y” axes are provided in response to a pivotal displacement of the control handle about a center point disposed within a housing. Rotation of the control handle about the center point is enabled through use of a pair of members having spherical exterior surfaces sharing a common center. The member includes a hemispherical-shaped shell coupled to the control handle shaft, and an end cap defining a spherical surface disposed at the end of the control handle shaft. The control handle shaft extends into the housing through an opening defined in an upper portion of the housing. The opening provides a bearing surface adapted to slidingly engage the spherical upper surface of the hemispherical-shaped shell. The housing further includes a lower portion with a receiver adapted to slidingly engage the end cap. A pair of nested gimbals disposed in the housing are respectively rotated about the X and Y axes through engagement with the control handle shaft. Preferably, the joystick further provides a third input axis (the “Z” axis), about which the control handle is rotated to produce a control input signal. Rotation of the control handle about each of the X, Y, and Z axes is monitored by a corresponding potentiometer that is coupled to the gimbals and the control handle shaft. Torsion springs oppose displacement of the control handle about each of the X, Y, and Z axes and return the control handle to a center position, for each axis.

Claims

1. A joystick, comprising:

(a) a multi-axis control assembly, including;

(i) a control handle upon which an input force is applied to pivotally displace the control handle;

(ii) a control handle shaft extending from an end of the control handle;

(iii) an end member defining a spherical surface having a first radius about a center point, the end member being coupled to the control handle shaft; and

(iv) a first hemispherical-shaped shell coupled to the control handle shaft and including a spherical exterior surface having a second radius different than the first radius about the center point;

(b) a housing that includes;

(i) a top portion comprising an opening having a bearing surface defined therein that is adapted to slidingly engage the spherical exterior surface of the first hemispherical-shaped shell; and

(ii) a base portion coupled to said top portion and including a receiver adapted to slidingly engage the spherical surface of the end member;

(c) a first angular position sensor operatively coupled to the control handle shaft so as to measure a rotation of the control handle about a first axis that extends through the center point; and

(d) a second angular position sensor operatively coupled to the shaft so as to determine a rotation of the control handle about a second axis that extends through the center point, wherein an input motion applied to the control handle causes the control handle shaft to be pivotally displaced about the center point so as to cause at least one of the angular position sensors to produce an output signal indicative of a direction and an extent of rotation of the control handle.

2. The joystick of claim 1, wherein said first and second axes are orthogonal.

3. The joystick of claim 1, further comprising:

(a) an upper gimbal pivotally mounted to said housing, comprising a yoke connected at opposing ends to support shafts having a common centerline coincident with the first axis and having a slot defined therein parallel to the first axis through which the control handle shaft extends, said slot being adapted to slidingly engage the control handle shaft, said upper gimbal being operatively coupled to said first angular position sensor; and

(b) a lower gimbal pivotally mounted to said housing, comprising a yoke connected at opposing ends to support shafts having a common centerline coincident with the second axis and having a slot defined therein parallel to the second axis through which the control handle shaft extends, said slot being adapted to slidingly engage the control handle shaft, said lower gimbal being operatively coupled to said second angular position sensor.

4. The joystick of claim 3, wherein each of the upper and lower gimbals is operatively coupled to corresponding springs that develop a bias force applied against the control handle when the control handle is pivotally displaced away from a center position.

5. The joystick of claim 4, wherein each of said springs comprises a torsion spring including a looped portion having a pair of tangs extending therefrom, each of said torsion springs being disposed in a holder coupled to a respective one of said upper or lower gimbals, said tangs engaging the housing and holder such that rotation of the control handle in either direction about one of said first and second axes causes a distance between the tangs of the torsion spring corresponding to that axis to change such that one of said tangs is caused to exert a force against the housing while the other tang exerts a force against the holder, producing a torque opposing the rotation about said one of the first and second axis and tending to restore the control handle to the center position.

6. The joystick of claim 3, wherein the yoke of the upper gimbal comprises a second hemispherical-shaped shell nested adjacent to the first hemispherical-shaped shell.

7. The joystick of claim 6, wherein the yoke of the lower gimbal comprises an upper surface substantially hemispherical in shape that is nested adjacent to an underside of the yoke of the upper gimbal.

8. The joystick of claim 1, wherein the control handle includes at least one input switch connected to at least one lead wire, and wherein the control handle shaft is hollow, said at least one lead wire extending through the control handle shaft into the housing.

9. The joystick of claim 1, wherein the control handle is rotatably mounted on the control handle shaft so as to be rotatable about a longitudinal axis of the control handle and the control handle shaft, further comprising a third angular position sensor that monitors the rotation of the control handle about said longitudinal axis.

10. The joystick of claim 9, wherein the control handle shaft is coupled with at least one of said upper and lower gimbals so as to prevent rotation of the control handle shaft about its longitudinal axis.

11. The joystick of claim 10, wherein the control handle shaft and the control handle are operatively coupled to a spring that produces a bias torque opposing rotation of the control handle about the longitudinal axis of the control handle shaft, away from a center position.

12. The joystick of claim 1, wherein each of said first axis and said second axis has an associated full range of motion through which the control handle may be rotated between a maximal displacement in each direction about that axis, and wherein the opening defined in the top portion of the housing is substantially rectangular in shape so as to enable the full range of motion about one of said first and second axes while maintaining the maximal displacement of the control handle about the other of said first and second axes.

13. The joystick of claim 12, wherein the first hemispherical-shaped shell comprises a perimeter divided into quadrants, a relief being defined in each quadrant thereof so as to enable the full range of motion about one of said first and second axes while maintaining the maximal displacement of the control handle about the other of the first and second axes.

14. The joystick of claim 1, wherein said first and second angular position sensors respectively comprise a first potentiometer and a second potentiometer, further comprising:

(a) a memory in which calibration data corresponding to each of said first and second potentiometers are stored; and

(b) a signal processing circuit electrically connected to each of said first and second potentiometers and said memory, for measuring voltages across each of said first and second potentiometers and producing respective corrected output signals indicative of a pivotal displacement of the control handle about said first and second axes by applying the calibration data to the voltages.

15. A joystick, comprising:

(a) a multi-axis control assembly, including;

(i) a control handle upon which an input force is applied to pivotally displace the control handle;

(ii) a control handle shaft extending from the control handle and having an end defining a spherical surface with a first radius; and

(iii) a first hemispherical-shaped shell coupled to the control handle shaft comprising a spherical exterior surface with a second radius;

(b) a housing that includes;

(i) a top portion comprising an opening,through which the control handle extends, said opening defining a bearing surface adapted to slidingly engage the spherical exterior surface of the hemispherical-shaped member; and

(ii) a bottom portion coupled to said top portion and comprising a receiver adapted to slidingly engage the spherical surface of the end of the control handle shaft;

(c) an upper gimbal pivotally mounted to said housing, comprising a yoke connected at opposing ends to respective support shafts having a common centerline defining a first gimbal axis and having a slot defined therein parallel to the first gimbal axis through which the control handle shaft extends, said slot slidingly engaging the control handle shaft;

(d) a lower gimbal pivotally mounted to said housing, comprising a yoke connected at opposing ends to respective support shafts having a common centerline defining a second gimbal axis and having a slot defined therein parallel to the second gimbal axis through which the control handle shaft extends, said slot slidingly engaging the control handle shaft;

(e) a first angular position sensor operatively coupled to the upper gimbal so as to monitor a rotation of the control handle about the first gimbal axis; and

(f) a second angular position sensor operatively coupled to the lower gimbal so as to monitor a rotation of the control handle about the second gimbal axis, wherein an input motion applied to the control handle causes the control handle to be pivotally displaced such that at least one of said upper and lower gimbals is rotated about its respective gimbal axis and at least one of the first and second angular position sensors provides an output signal indicative of a direction and an extent of rotation of the control handle.

16. The joystick of claim 15, wherein said first and second gimbals are disposed such that the first gimbal axis is orthogonal to the second gimble axis.

17. The joystick of claim 15, wherein the first radius and second radius share a substantially common center point such that an input motion applied to the control handle causes the control handle shaft to be pivotally displaced about the common center point.

18. The joystick of claim 17, wherein the upper and lower gimbal axes generally pass through the common center point.

19. The joystick of claim 15, wherein each of the first and second gimbals are pivotally mounted to the housing by a corresponding trunnion bearing mount.

20. The joystick of claim 15, wherein said first and second angular position sensors respectively comprise a first potentiometer and a second potentiometer, further comprising:

(a) a memory in which calibration data corresponding to each of said first and second potentiometers are stored; and

(b) a signal processing circuit electrically connected to each of said first and second potentiometers and said memory, for measuring voltages across each of said first and second potentiometers and producing respective corrected output signals indicative of a pivotal displacement of the control handle about said first and second axes by applying the calibration data to the voltages.

21. The joystick of claim 15, wherein each of the upper and lower gimbals is operatively coupled to corresponding springs that develop a bias force applied against the control handle when the control handle is pivotally displaced away from a center position.

22. The joystick of claim 21, wherein each of said springs comprises a torsion spring including a looped portion having a pair of tangs extending therefrom, each of said torsion springs being disposed in a holder coupled to a respective one of said upper or lower gimbals, said tangs engaging the housing and holder such that rotation of the control handle in either direction about one of said first and second gimbal axes causes a distance between the tangs of the torsion spring corresponding to that gimbal axis to change such that one of said tangs exerts a force against the housing while the other tang exerts a force against the holder, producing a torque opposing the rotation of the control handle about said one of the first and second gimbal axes and tending to restore the control handle to the center position.

23. The joystick of claim 15, wherein yoke of the upper gimbal comprises a second hemispherical-shaped shell nested adjacent to the first hemispherical-shaped shell.

24. The joystick of claim 15, wherein the yoke of the lower gimbal comprises an upper surface substantially hemispherical in shape that is nested adjacent to the second hemispherical shell of the upper gimbal.

25. The joystick of claim 15, wherein the control handle comprises at least one input switch connected to at least one lead wire, and wherein the control handle shaft is hollow so as to enable routing of said at least one lead wire through the control handle shaft.

26. The joystick of claim 15, wherein the control handle is rotatably mounted to the control handle shaft so as to be rotatable about a longitudinal axis of the control handle and the control handle shaft, further comprising a third angular position sensor that monitors the rotation of the control handle about said longitudinal axis.

27. The joystick of claim 26, wherein the control handle shaft is coupled with at least one of said upper and lower gimbals so as to prevent rotation of the control handle shaft about its longitudinal axis.

28. The joystick of claim 26, wherein the control handle shaft and control handle are operatively coupled to a spring such that a bias torque is applied against the control handle when the control handle is rotated about the longitudinal axis, away from a center position.

29. The joystick of claim 15, wherein each of said first gimbal axis and said second gimbal axis has an associated full range of motion through which the control handle may be rotated between a maximal displacement in each direction about that axis, and wherein the opening defined in the top portion of the housing is substantially rectangular in shape so as to enable the full range of motion about one of said first and second gimbal axes while maintaining the maximal displacement of the control handle about the other of said first and second gimbal axes.

30. The joystick of claim 29, wherein the first hemispherical-shaped shell comprises a perimeter divided into quadrants, a relief being defined in each quadrant so as to enable the full range of motion about one of said first and second axes while maintaining the maximal displacement of the control handle about the other of the first and second axes.

31. A joystick comprising:

(a) a base, said base comprising a receiver, an upper gimbal and a lower gimbal;

(b) a control handle shaft comprising a longitudinal axis and a spherical end member pivotally coupled to the receiver so as to allow a pivotal displacement of the control handle shaft about a first axis and a second axis, the control handle shaft passing through said upper gimbal and lower gimbal, the gimbals substantially preventing rotation of the control handle shaft about the longitudinal axis;

(c) a control handle upon which an input force is applied to pivotally displace the control handle shaft about the base, said control handle being rotatably coupled to the control handle shaft so as to enable rotation of the control handle about the longitudinal axis; and

(d) an angular position sensor operatively coupled to the control handle so as to measure a rotational displacement of the control handle about the longitudinal axes.

32. The joystick of claim 31, wherein the angular position sensor comprises a potentiometer that is fixedly coupled to one of the control handle and the control handle shaft and includes an input member coupled to the other of the control handle and the control handle shaft.

33. The joystick of claim 31, wherein the control handle and control handle shaft are operatively coupled to a spring that develops a bias force applied against the control handle when the control handle is rotated about the longitudinal axis, away from a center position.

34. The joystick of claim 33, wherein said spring comprises a torsion spring including a looped portion having a pair of tangs extending therefrom, said torsion spring being disposed in a holder coupled to the control handle shaft, said tangs engaging the control handle and the holder such that rotation of the control handle in either direction about the longitudinal axis causes a distance between the tangs to change, one of said tangs then exerting a force against the control handle while the other tang exerts a force against the holder, producing a torque opposing the rotation of the control handle about the longitudinal axis and tending to restore the control handle to the center position.

35. A joystick comprising:

(a) a base;

(b) a control handle pivotally coupled to the base so as to pivotally rotate about at least a first axis and a second axis, wherein for each of said first and second axes, the control handle can be pivotally displaced in opposite directions up to a maximal displacement, and wherein the control handle has a centered position about each of said first and second axis when there is no force applied to the control handle by a user;

(c) a first potentiometer operatively coupled to the joystick and the base so as to produce a voltage output signal that is substantially proportional to a pivotal displacement of the control handle about the first axis;

(d) a second potentiometer operatively coupled to the joystick and the base so as to produce a voltage output signal that is substantially proportional to a pivotal displacement of the control handle about the second axis;

(e) a memory in which calibration data for said first and second potentiometers are stored, wherein the memory stores a plurality of microcode instructions, and said calibration data comprise a pair of limit values for each of said first and second axes derived from the first and second potentiometers when the control handle is pivotally displaced to the maximal displacement in each direction about said first and second axes; and

(f) a signal processing circuit electrically connected to said first and second potentiometers and said memory, said signal processing circuit processing voltages derived from said first and second potentiometers and producing respective corrected signals corresponding to a pivotal displacement of the joystick about said first and second axes by correcting the voltages with the calibration data stored in said memory, wherein execution of said plurality of microcode instructions by the processing circuit enable the joystick to;

(i) determine a center position value for each of said first and second axes when the control handle is in the centered position about each of the first and second axes; and

(ii) determine at least one scaling correction for each of said first and second axes, based on the centered position that is determined for that axis and the limit values for that axis, wherein said center position value and said at least one scaling correction is used to determine a corrected signal for that axis.

36. The joystick of claim 35, wherein the signal processing circuit comprises:

(a) an analog-to-digital converter that receives the voltages derived from said first and second potentiometers and converts said voltages into corresponding digitized signals; and

(b) a processor coupled to the memory and to the analog-to-digital converter to receive said digitized signals, said processor executing said plurality of microcode instructions to convert the digitized signals into the corrected signals.

37. The joystick of claim 36, wherein the processor comprises a microcontroller, and wherein the analog-to-digital converter and memory are embedded in the microcontroller.

38. The joystick of claim 36, wherein the signal processing circuit further comprises a passive filter disposed between each of said first and second potentiometers and said analog-to-digital converter.

39. The joystick of claim 36, wherein the digitized signals include extraneous noise and the signal processing circuit further comprises an active filter disposed between the analog-to-digital converter and the processor, said active filter receiving said digitized signals as an input and filtering said extraneous noise to produce filtered signals that are input to the processor to produce the corrected signals.

40. The joystick of claim 36, wherein execution of said plurality of microcode instructions causes the processor to filter the digitized signals to remove extraneous noise from the digitized signals prior to producing the corrected signals.

41. The joystick of claim 36, wherein execution of said plurality of microcode instructions causes the processor to encode the corrected signals corresponding to each of said first and second axes into a composite control signal that is formatted for transmission over a communication link.

42. The joystick of claim 41, wherein the communication link comprises a Universal Serial Bus interface.

43. The joystick of claim 35, wherein a unique serial number is stored in the memory and is available to a Universal Serial Bus interface to which the joystick is adapted to be connected, so as to uniquely identify the joystick.

44. The joystick of claim 35, wherein the center position value for each of said first and second axes and said at least one scaling correction are automatically performed in response to a power-on reset of the joystick.

45. The joystick of claim 36, wherein execution of said plurality of microcode instructions further causes the processor to:

(a) monitor the voltages derived from first and second potentiometers in response to a pivotal displacement of the joystick about each of said first and second axes, to determine if the limit values stored in the memory for said first and second axes has been exceeded;

(b) in response to a determination that a limit value has been exceeded, modifying the calibration data corresponding to that limit value as a function of at least one voltage derived from the potentiometer that was determined to exceed the limit value; and

(c) storing modified calibration data in said memory.

46. A joystick comprising:

(a) a control handle shaft comprising a longitudinal axis and a spherical end member;

(b) a control handle upon which an input force is applied to pivotally displace the control handle shaft, said control handle being rotatably coupled to the control handle shaft so as to enable rotation of the control handle about the longitudinal axis;

(c) a housing that includes;

(i) a top portion comprising an opening through which said control handle shaft passes, such that said top portion is displaced by the control handle shaft as the control handle shaft is pivotally displaced, said opening preventing said control handle shaft from freely rotating; and

(ii) a base portion coupled to said top portion and including a receiver adapted to pivotally engage the spherical surface of the end member; and

(d) at least one angular position sensor operatively coupled to the control handle so as to measure a rotational displacement of the control handle about the longitudinal axes.