Method and apparatus for providing damping force feedback

• US 5,721,566 A
• Filed: 06/09/1995
• Issued: 02/24/1998
• Est. Priority Date: 01/18/1995
• Status: Expired due to Term

• Current Assignee: Immersion Corporation
• Original Assignee: Immersion Human Interface Corporation
• Inventors: Schena, Bruce M., Rosenberg, Louis B., Gillespie, Richard B.
• Primary Examiner(s): CHOW, DOON Y
• Application Number:
  US08/489,068
• Time in Patent Office: 991 Days
• Field of Search: 345/156, 345/157, 345/161, 345/162, 345/179, 74/471 XY, 200/6 A, 341/21, 178/18, 178/19, 318/568.1, 318/568.16, 318/568.17
• US Class Current: 345/161
• CPC Class Codes: A61B 90/50 Supports for surgical instruments, e.g. articulated arms
• CPC Class Codes: A63F 13/21 characterised by their sensors, purposes or types
• CPC Class Codes: A63F 13/24 Constructional details thereof, e.g. game controllers with detachable joystick handles
• CPC Class Codes: A63F 13/285 Generating tactile feedback signals via the game input device, e.g. force feedback
• CPC Class Codes: A63F 13/42 by mapping the input signals into game commands, e.g. mapping the displacement of a stylus on a touch screen to the steering angle of a virtual vehicle
• CPC Class Codes: A63F 13/57 Simulating properties, behaviour or motion of objects in the game world, e.g. computing tyre load in a car race game A63F13/56 takes precedence
• CPC Class Codes: A63F 2300/1006 having additional degrees of freedom
• 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: A63F 2300/1043 being characterized by constructional details
• CPC Class Codes: A63F 2300/6045 for mapping control signals received from the input arrangement into game commands
• CPC Class Codes: A63F 2300/64 for computing dynamical parameters of game objects, e.g. motion determination or computation of frictional forces for a virtual car
• CPC Class Codes: A63F 2300/8082 Virtual reality
• CPC Class Codes: G05G 2009/0474 characterised by means converting mechanical movement into electric signals
• CPC Class Codes: G05G 2009/04766 providing feel, e.g. indexing means, means to create counterforce
• CPC Class Codes: G05G 9/047 the controlling member being movable by hand about orthogonal axes, e.g. joysticks for switches H01H25/04
• CPC Class Codes: G05G 9/04737 with six degrees of freedom
• 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
• CPC Class Codes: G06F 3/0338 with detection of limited linear or angular displacement of an operating part of the device from a neutral position, e.g. isotonic or isometric joysticks
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/0383 : Signal control means within the pointing device
• CPC Class Codes: G09B 23/28 : for medicine
• CPC Class Codes: G09B 9/28 : Simulation of stick forces or the like
• CPC Class Codes: Y10T 74/20201 : Control moves in two planes

Abstract

A method and apparatus for interfacing the motion of an object with a digital processing system includes a sensor for detecting movement of the object along a degree of freedom. A passive pneumatic or hydraulic damper is coupled to the object to provide a damping resistance to the object along the degree of freedom and resist a movement of the object. The damping resistance is provided by regulating the control of a fluid with a digital computing apparatus, thus providing a low-cost, low-power force-feedback interface that is safe for the user. The damper and sensor provide an electromechanical interface between the object and the electrical system. A gimbal or other interface mechanism can be coupled between the damper and the object. The interface is well suited for simulations or video games in which an object such as a joystick is moved and manipulated by the user.

Claims

1. An apparatus for interfacing the motion of an object with a host computer, said host computer updating a graphical simulation in response to user manipulation of said object and commanding said apparatus to generate force feedback sensations in coordination with events within said graphical simulation, said apparatus comprising:

a support mechanism providing a degree of freedom to said object with respect to a grounding surface, wherein said object is moveable along said at least one degree of freedom by a user grasping said object;

a sensor electrically coupled to said host computer through an interface and coupled to said support mechanism for sensing motion of said object along said first degree of freedom and providing signals to said host computer representing said sensed motions; and

an actuator electrically coupled to said host computer and mechanically coupled to said object to create a passive damping resistance to motion of said object along said degree of freedom, said damping resistance resulting from fluid flow through an orifice and being varied by regulating a rate of passive flow of said fluid through said orifice in response to signals from said host computer.

2. An apparatus as recited in claim 1 wherein said support mechanism includes a gimbal mechanism providing a first revolute degree of freedom to said object engaged with said gimbal mechanism about a first axis of rotation.

3. An apparatus as recited in claim 2 wherein said gimbal mechanism provides a second degree of freedom to said object about a second axis of rotation, and further comprising a second sensor for sensing positions of said object along said second degree of freedom and a second actuator to create a passive damping resistance along said second degree of freedom by regulating a rate of a passive flow of a second fluid.

4. An apparatus as recited in claim 3 wherein said gimbal mechanism includes a closed loop five member linkage.

5. An apparatus as recited in claim 4 wherein said five member linkage includes:

a ground member coupled to said grounding surface;

first and second extension members, each extension member being coupled to said ground member;

first and second central members, said first central member having an end coupled to said first extension member and said second central member having an end coupled to said second extension member, wherein said central members are rotably coupled to each other at ends not coupled to said extension members.

6. An apparatus as recited in claim 3 wherein said actuator includes a piston assembly and a valve.

7. An apparatus as recited in claim 6 wherein said piston assembly includes a cylinder and a piston operative to move within said cylinder, said piston being coupled to said object by a piston rod.

8. An apparatus as recited in claim 7 wherein said piston rod includes two ends, each end including a ball joint.

9. An apparatus as recited in claim 7 wherein said fluid is air.

10. An apparatus as recited in claim 9 wherein said object includes a joystick.

11. An apparatus as recited in claim 7 wherein said valve is an on-off valve having an open state and a closed state.

12. An apparatus as recited in claim 7 wherein said valve is a servo valve having a passage having a variable size, said size of said passage selected by said host computer to determine an amount of damping resistance on said object.

13. An apparatus as recited in claim 1 further comprising a second actuator electrically coupled to said host computer and mechanically coupled to said support mechanism to create a passive damping resistance to movement of said object along a second degree of freedom, said second actuator including a damping mechanism that provides said damping resistance by regulating a rate of passive flow of a fluid through said orifice in response to signals from said host computer.

14. An apparatus as recited in claim 13 wherein said support mechanism includes a first linear member coupled between said object and said actuator to provide a first linear degree of freedom to said object, and a second linear member coupled between said object and said second actuator to provide a second linear degree of freedom to said object.

15. An apparatus as recited in claim 14 wherein said first linear member is a flexible member that flexes when said object is moved in said second degree of freedom, and wherein said second linear member is a flexible member that flexes when said object is moved in said first degree of freedom.

16. A method for interfacing motion of an object with a host computer, said host computer updating a graphical environment in response to user manipulation of said object and commanding said apparatus to generate force feedback sensations in coordination with events within said graphical environment, the method comprising

providing an object having a degree of freedom with respect to a ground surface, said object being grasped by a user;

sensing positions of said object along said degree of freedom with respect to said ground surface using a sensor and producing electrical sensor signals therefrom, said electrical sensor signals being received by said host computer; and

creating a passive damping resistance to movement of said object along said degree of freedom, said passive damping resistance being created by the passive flow of a fluid through an orifice caused by said user'"'"'s manipulation of said object, wherein said passive damping resistance is changed by adjusting an amount of said passive flow of said fluid through said orifice in response to signals received from said host computer.

17. A method as recited in claim 16 wherein said degree of freedom is a rotary degree of freedom.

18. A method as recited in claim 16 wherein said degree of freedom is a linear degree of freedom.

19. A method as recited in claim 16 wherein said step of creating a resistance to movement of said object includes coupling a passive brake to said object to provide said resistance, said brake including a piston assembly and a valve to regulate said flow of said fluid.

20. A method as recited in claim 19 wherein said fluid is air, and wherein said piston assembly and said valve comprise an open loop system for circulating air supplied externally to said piston assembly and said valve.

21. A method as recited in claim 19 wherein said piston assembly and said valve comprise a closed loop system for circulating a substantially fixed amount of said fluid within said piston assembly and said valve.

22. A method as recited in claim 16 wherein said creating a passive damping is accomplished using an electrorheological fluid and a plurality of electrodes such that said adjusting said passive flow of said fluid is accomplished by applying a voltage to said electrodes to control a viscosity of said electrorheological fluid and thereby regulate said flow of said fluid.

23. A computer interface device for use with a host computer updating a graphical simulation in response to user manipulation of said interface device, said host computer commanding said computer interface device to generate force feedback sensations in coordination with events within said graphical simulation, said interface device comprising:

a user object grasped by a user;

a support mechanism which supports said user object while allowing a degree of freedom of motion of said object with respect to a grounding surface;

an actuator for providing resistance to motion of said user object along said degree of freedom of said user object, said actuator including a grounded portion and a non-grounded portion, wherein said grounded portion of said actuator remains stationary with respect to said grounding surface, and wherein said resistance to motion is varied by said actuator in response to commands from said host computer;

a coupling mechanism provided between said actuator and said user object, said coupling mechanism allowing play between said user object and said non-grounded portion of said actuator; and

a sensor system, said sensor system being grounded wherein a portion of said sensor system remains stationary with respect to said grounding surface, and wherein a different portion of said sensor system is coupled to said user object and moves with respect to said grounding surface when said user object moves along said degree of freedom, wherein no substantial play is allowed between said user object and said portion of said grounded sensor system coupled to said user object, said motion of said coupled sensor portion resulting in signals representing a position of said user object along said degree of freedom.

24. A computer interface device as recited in claim 23 wherein a magnitude of said play is measurable by said sensor system within a sensing resolution of said sensor system.

25. A computer interface device as recited in claim 23 wherein said play is rotary backlash.

26. A computer interface device as recited in claim 25 wherein said coupling mechanism that allows rotary backlash between said actuators and said user object includes gears.

27. A computer interface device as recited in claim 23 wherein one of said portions of said sensor system includes an emitter of electromagnetic energy and another of said portions of said sensor system includes a detector of said electromagnetic energy.

28. A computer interface device as recited in claim 23 wherein said resistance to motion is a damping resistance.

29. A computer interface device as recited in claim 23 wherein said resistance to motion is a force proportional to a velocity of said user object.

30. A computer interface device as recited in claim 23 wherein said resistance to motion is a sensation representing the feel of moving through a fluid.

31. A computer interface device as recited in claim 23 wherein said resistance to motion is a sensation representing the feel of contacting a wall.

32. A computer interface device as recited in claim 23 wherein said resistance to motion is a sensation representing the feel of moving over a texture.

33. A computer interface device as recited in claim 23 further including a local microprocessor separate from said host computer, said local microprocessor electrically coupled to said actuator and to said sensor system such that said local microprocessor is operative to control said actuator and read said sensor, said local microprocessor coupled to said host computer by a communication interface and executing a local process in parallel with host execution of said graphical simulation.

34. A computer interface device as recited in claim 33 wherein said host computer sends commands to said local microprocessor indicating a magnitude of said damping resistance to be applied by said actuator.

35. A computer interface device as recited in claim 33 wherein said host computer sends commands to said local microprocessor, said commands indicating a direction of said damping resistance to be applied by said actuator.

36. A computer interface device as recited in claim 33 wherein said local microprocessor reads said sensor system locally to detect free motion of said user object within a play region defined by said play and adjust resistance applied by said actuator based on said motion in said play region.

37. A computer interface device as recited in claim 23 wherein said actuator is a pneumatic actuator.

38. A computer interface device as recited in claim 23 wherein said actuator is an electromagnetic actuator.

39. A computer interface device as recited in claim 23 wherein said actuator includes a fluid that changes its viscous properties in response to an electromagnetic field.

40. A computer interface device as recited in claim 23 wherein said play is torsion flex.

41. A joystick interface device for use with a host computer updating a graphical simulation in response to user manipulation of said interface device, said host computer commanding said interface device to generate force feedback sensations in coordination with events within said graphical simulation, said interface device comprising:

a joystick handle grasped by a user;

a support mechanism which supports said joystick handle while allowing at least two degrees of freedom of motion of said joystick handle with respect to a grounding surface;

two actuators coupled to said joystick handle, said actuators providing resistance to motion of said joystick handle along each of said two degrees of freedom, wherein a portion of each of said actuators remains stationary with respect to said grounding surface, wherein a coupling between said joystick handle and each of said actuators introduces play between said joystick handle and each of said actuators, and wherein said resistance to motion is varied by said actuators in response to commands from said host computer; and

a grounded sensor system in which a portion of said sensor system remains stationary with respect to said grounding surface and a different portion of said sensor system is coupled to said joystick handle such that no substantial play is allowed between said joystick handle and said different portion of said sensor system, said lack of substantial play allowing said sensor to accurately track the position of said joystick handle along at least one of said degrees of freedom, regardless of said resistance provided by said actuator.

42. A joystick interface device as recited in claim 41 wherein the magnitude of said play is measurable by said sensor system within a sensing resolution of said sensor system.

43. A joystick interface device as recited in claim 41 wherein said play is rotary backlash.

44. A joystick interface device as recited in claim 43 wherein said coupling mechanism that allows rotary backlash between said actuators and said joystick handle includes gears.

45. A joystick interface device as recited in claim 41 wherein said sensory system is an optical sensor system wherein one said portions of said sensor system includes an emitter and wherein another one of said portions of said sensor system includes a detector of electromagnetic energy.

46. A joystick interface device as recited in claim 41 wherein said resistance to motion is a damping resistance.

47. A joystick interface device as recited in claim 41 wherein said resistance to motion is a force proportional to the velocity of said joystick handle.

48. A joystick interface device as recited in claim 41 wherein said resistance to motion is a sensation representing the feel of moving through a liquid.

49. A joystick interface device as recited in claim 41 wherein said resistance to motion is a sensation representing the feel of contacting a wall.

50. A joystick interface device as recited in claim 41 wherein said resistance to motion is a sensation representing the feel of moving over a texture.

51. A joystick interface device as recited in claim 41 wherein said support mechanism includes a five-member gimbal.

52. A joystick interface device as recited in claim 41 wherein said actuators are pneumatic actuators.

53. A joystick interface device as recited in claim 41 wherein said actuator includes a fluid that changes its viscous properties in response to an electromagnetic field.

54. An interface apparatus for interfacing the motion of a user object with a host computer system, said host computer system updating a graphical simulation in response to user manipulation of said interface apparatus, said host computer commanding said interface apparatus to generate force feedback sensations in coordination with events within said graphical simulation, comprising:

a user object grasped by a user and manipulable by said user in at least one degree of freedom;

a sensor coupled to said user object such that substantially no play exists between said sensor and said user object, allowing said sensor to accurately track a position of said user object in said at least one of said degree of freedom; and

an actuator coupled to said user object and coupled to said sensor, said actuator outputting a damping resistance on said user object, wherein an amount of play exists between said actuator and said user object and between said actuator and said sensor allowing movement of said user object to be detected by said sensor regardless of an amount of damping resistance output by said actuator.

55. An interface device for use with a host computer, said host computer commanding said interface device to generate force feedback sensations in coordination with events within a host application, said interface device comprising:

a user object engaged by a user;

a support mechanism which supports said user object while allowing at least two degrees of freedoms of motion of said user object with respect to a base;

two grounded actuators coupled to said user object wherein rotary backlash between said object and each of said actuators introduces play between said object and each of said grounded actuators, said grounded actuators providing resistance to motion of said object along each of said two degree of freedom, wherein a portion of each of said actuators remains stationary with respect to said base, and wherein said resistance to motion is varied by said actuators in response to commands from said host computer; and

a sensor system grounded such that a portion of said sensor system remains stationary with respect to said grounding surface, and wherein a different portion of said sensor system is coupled to said user object such that substantially no play exists between said object and said coupled portion of said sensor system, said lack of play allowing said sensor system to accurately track a position of said user object along at least one of said degrees of freedom regardless of said resistance provided by said actuators.

56. An interface device for use with a host computer system displaying a graphical object within a graphical environment, said host computer system updating the location of said graphical object in response to user manipulation of said interface device, said host computer system commanding force resistance to said interface device in coordination with interactions between said graphical object and said graphical environment, said interface device comprising:

a user object grasped by a user and movable in a plurality of degrees of freedom with respect to said fixed surface;

a tranducer system coupled to said user manipulatable object, said transducer system including an actuator and a sensor, said actuator providing damping resistance to motion of said user manipulatable object, and said sensor detecting movement of said user manipulatable object along a degree of freedom and generating a sensor signal;

a local microprocessor separate from said computer system and coupled to said transducer system for executing a process in parallel with said host computer system, said microprocessor reporting data to said computer system representative of said sensor signal, said microprocessor receiving a command from said host computer system and causing said transducer system to provide said damping resistance to motion of said object in accordance with said host command, wherein said microprocessor decodes said host command and determines a magnitude of a damping resistance to be applied on said user object that is coordinated with said host computer system updating said graphical environment, wherein said damping resistance produced by said transducer system upon said user object simulates a feel of at least one of a plurality of feel sensations, said feel sensations including moving through a fluid, moving over a textured surface, and colliding with a simulated obstruction.

57. A device as recited in claim 56 wherein said local microprocessor controls said transducer system to vary the resistance on said user object at a desired frequency.

58. A device as recited in claim 56 wherein said graphical object is a cursor and wherein said interface device simulates a feel of moving through a fluid when said cursor is moved through a displayed region in said graphical environment.

59. A device as recited in claim 56 wherein said graphical object is a cursor and wherein said interface device simulates the feel of encountering an obstacle when said cursor is moved into a graphically displayed obstruction.

60. A device as recited in claim 56 wherein said process decodes said host command and determines if said resistance to be applied to said user object should be uni-directional or bi-directional from information in said host command.

61. An interface device as recited in claim 56 wherein said actuator includes a fluid-controlled damper which provides resistance to motion of said user object in response to host commands from said host computer which command an amount of fluid flow through an orifice of said damper.

62. An interface device as recited in claim 56 wherein said user object is movable in two degrees of freedom that define a planar region and wherein said interface device includes two transducer systems to sense a position and provide resistance in said two degrees of freedom.

63. An interface device as recited in claim 62 wherein said user object is a stylus-receiving user object.

64. An interface device as recited in claim 62 wherein said user object is a finger-receiving user object.

65. An interface device as recited in claim 62, further comprising a first linear member and a second linear member coupled between said user object and said transducer systems, wherein first linear member is a flexible member that flexes when said object is moved in said second degree of freedom, and wherein said second linear member is a flexible member that flexes when said object is moved in said first degree of freedom.

66. An interface device for use with a host computer, said host computer commanding said interface device to generate force feedback sensations in coordination with events within a host application, said interface device comprising:

a user object engaged by a user;

a support mechanism which supports said user object while allowing two degrees of freedoms of motion of said user object with respect to a base wherein said two degrees of freedom allow said user object to move in a plane;

two linear actuators coupled to said user object for providing resistance to motion of said object along each of said two degree of freedom, wherein said linear actuators are grounded such that a portion of each of said linear actuators remains stationary with respect to said base, and wherein said resistance to motion is varied by said linear actuators in response to commands from said host computer; and

a grounded sensor system including a portion that remains stationary with respect to said grounding surface, and wherein a different portion of said sensor system is coupled to said user object such that substantially no play is allowed between said object and said different portion of said sensor along one of said degrees of freedom, said substantial lack of play allowing said sensor to accurately track the position of said user object along said degrees of freedom.

67. An interface device as recited in claim 66 wherein a coupling between each of said linear actuators and said user object includes a flexure.

68. An interface device as recited in claim 66 wherein a coupling between each of said linear actuators and said user object includes a link member with first and second ends, wherein each of said ends includes a rotary joint.

69. An interface device as recited in claim 66 wherein said sensor system is a linear optical sensor.

70. An apparatus for interfacing the motion of a user object with a host computer system comprising:

a sensor for detecting movement of said user object along a degree of freedom, said sensor being operative to develop a sensor signal, wherein a representation of said sensor signal is reported to said host computer system over a communication interface;

an actuator coupled to said object for imparting resistance to movement of said user object in response to a command from said host computer sent over a communication interface;

a local microprocessor separate from said host computer and executing routines in parallel with host execution of a graphical simulation, said local microprocessor reading said sensor signal and reporting a representation of said sensor signal to said host computer, said local microprocessor receiving a host command from said host computer and controlling said actuator in response to said host command, said host command specifying the magnitude of a damping resistance to be generated by said actuator for movement of said object along a particular direction of said degree of freedom; and

a local routine executing on said local microprocessor for controlling said actuator to produce a damping resistance of said specified magnitude, said local routine monitoring said sensor signal, determining a direction of motion of said user object along said degree of freedom, and modifying the magnitude of damping resistance to be generated by said actuator in response to said direction.

71. An apparatus as recited in claim 70 wherein said damping is uni-directional such that a damping resistance is set by said local microprocessor to a magnitude indicated by said host command when user object moves in a first direction along said degree of freedom and is set to zero when said user object moves in a second direction opposite to said first direction along said degree of freedom, thereby allowing said user to feel a simulated damping resistance when moving in only one direction along said degree of freedom.

72. An apparatus as recited in claim 71 wherein said uni-directional damping is used in a tactile simulation of a collision with an obstacle.

73. An apparatus as recited in claim 70 wherein said host command indicates a degree of freedom associated with the specified damping resistance magnitude.

74. An apparatus as recited in claim 73 wherein said host command also indicates the direction of motion associated with the specified degree of freedom.

75. An apparatus as recited in claim 70 wherein said user object is a joystick allowing two degrees of freedom specified as horizontal and vertical, wherein said specified damping can be provided in either said horizontal or said vertical degree of freedom.

76. An apparatus as recited in claim 70 wherein said local microprocessor controls said actuator to simulate three different tactile sensations including a simulated obstruction, a simulated texture, and a simulated fluid.

77. An apparatus as recited in claim 70 wherein said local microprocessor controls said actuator to vary said resistance to motion on said user object at a desired frequency.

78. An apparatus as recited in claim 70 wherein said host computer system executes a video game.