Method and apparatus for tracking the position and orientation of a stylus and for digitizing a 3-D object

• US 5,724,264 A
• Filed: 08/07/1995
• Issued: 03/03/1998
• Est. Priority Date: 07/16/1993
• Status: Expired due to Term

• Current Assignee: Emory University, Immersion Corporation
• Original Assignee: Immersion Human Interface Corporation
• Inventors: Schena, Bruce M., Rosenberg, Louis B., Jackson, Bernard G.
• Primary Examiner(s): Voeltz, Emanuel T.
• Assistant Examiner(s): Wachsman, Hal D.
• Application Number:
  US08/512,084
• Time in Patent Office: 939 Days
• Field of Search: 364/559-563, 364/190, 364/167.01, 364/474.03, 364/474.17, 364/474.22, 364/474.28, 364/474.29, 364/474.34, 364/474.36, 364/474.37 , 364/505, 364/506, 364/551.02, 364/413.13, 364/571.01, 364/571.05, 364/709.11, 364/578, 901/41, 901/15, 901/3, 901/40, 901/27-29, 901/13, 33/556, 33/558, 33/502-505, 33/559, 33/561, 33/1 MP, 33/1 PT, 33/1 CC, 33/551, 395/82, 395/83, 395/86, 395/93, 395/96, 395/99, 73/866.5, 73/862.041, 73/862.043, 82/1.11, 82/1.2, 269/900, 74/813 R, 74/813 C, 74/479.01, 74/490.01, 74/490.05-490.07, 74/490.09, 74/471 XY, 345/179, 345/161, 345/168, 345/156, 178/18, 433/72, 128/653.1, 128/662.06, 128/897, 128/774, 414/5, 318/567, 318/568.11, 318/432, 318/561, 318/568.2, 318/568.24, 318/25, 600/201, 250/231.14
• US Class Current: 702/152
• 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: B25J 9/1692 Calibration of manipulator
• CPC Class Codes: G01B 21/04 by measuring coordinates of points
• CPC Class Codes: G01B 21/042 Calibration or calibration artifacts G01B3/30, G01B9/02072 take precedence
• CPC Class Codes: G01B 5/008 using coordinate measuring machines
• CPC Class Codes: G05B 19/4207 in which a model is traced or scanned and corresponding data recorded
• CPC Class Codes: G05B 2219/37021 Robot controls position of touch probe
• CPC Class Codes: G05B 2219/37043 Touch probe, store position of touch point on surface
• CPC Class Codes: G05B 2219/39015 With different manipulator configurations, contact known sphere, ballbar
• CPC Class Codes: G05B 2219/39021 With probe, touch reference positions
• CPC Class Codes: G05B 2219/39024 Calibration of manipulator
• CPC Class Codes: G05B 2219/39048 Closed loop kinematic self calibration, grip part of robot with hand
• CPC Class Codes: G05B 2219/45055 Assembly
• CPC Class Codes: G05B 2219/45061 Measuring robot
• 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 3/0346 with detection of the device orientation or free movement in a 3D space, e.g. 3D mice, 6-DOF [six degrees of freedom] pointers using gyroscopes, accelerometers or tilt-sensors
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry
• CPC Class Codes: G06F 3/0383 Signal control means within the pointing device
• CPC Class Codes: H01H 2003/008 with a haptic or a tactile feedback controlled by electrical means, e.g. a motor or magnetofriction

Abstract

A method and apparatus for measuring three-dimensional (3-D) coordinates. A 3-D object can be digitized into a mesh representation manipulable by a computer system by tracing a stylus of a probe apparatus over surfaces of the object. The probe apparatus includes an arm having a series of linkages and joints. The arm can be assembled by placing the joints of the arm in joint fixtures a desired distance and angle apart and bonding the joints to a linkage. The probe apparatus is calibrated by placing the tip of the stylus at an arbitrary point in a work volume and varying the stylus'"'"' orientation to find error values and determine calibration parameters. The sensors of the probe apparatus are zeroed by placing the probe apparatus in the only possible home position and assigning assumed starting angles to the sensors. A rotary table can be used to support the object being digitized, where the rotation of the rotary table and object during digitization is sensed and included in coordinate calculations. A mesh representation of the object is developed by a computer system by incrementally creating and displaying triangles from data points of contour lines of the mesh. A selection template allows commands to be selected by the stylus by defining a template having selection areas within the probe'"'"'s work volume and associating the selection areas with specific commands to the host computer.

Claims

1. A method for locating the position and orientation of a rotary table apparatus with reference to a probe apparatus, said rotary table and said probe apparatus used for measuring three-dimensional geometry of an object placed on a surface of said rotary table, the method comprising:

providing a base portion of said rotary table apparatus on a first surface;

providing a base of said probe apparatus on said first surface, said probe apparatus including a probe connected to said base of said probe apparatus by an arm linkage including rotary joints that allow said probe to move in multiple degrees of freedom;

placing a tip of said probe of said probe apparatus on a fixed location of a turntable portion of said rotary table apparatus;

rotating said turntable portion of said rotary table apparatus while maintaining said probe at said fixed location on said turntable portion such that said fixed location and said probe are moved through a plurality of angular positions in at least a portion of a circle;

sampling data from sensors included in said joints of said arm linkage of said probe apparatus as said turntable is rotated, said data including representations of a position and an orientation of said probe at a plurality of different angular positions of said turntable portion;

detecting a change in angular positions of said turntable portion with respect to said base portion as said turntable is rotated; and

determining the position and orientation of said surface of said rotary table apparatus relative to said base portion of said probe apparatus, said position and orientation being determined utilizing said data sampled at said plurality of different angular positions of said turntable portion from said probe sensors and utilizing said detected change in said angular positions of said turntable portion, thereby allowing new rotary positions of said object to be known during said measuring of said three-dimensional geometry of said object after said rotary table and said object have been rotated during said measuring.

2. A method as recited in claim 1 wherein said rotary table includes a table sensor coupled between said base portion and said turntable portion for providing data describing said change in angular position of said turntable portion with respect to said base portion when said turntable is rotated.

3. A method as recited in claim 2 wherein said probe is a stylus held by a hand of a user, and wherein said fixed location on said turntable is a receptacle shaped to receive a tip of said stylus and to hold said stylus tip at said fixed location when said turntable is rotated.

4. A method as recited in claim 3 wherein said receptacle is positioned near a periphery of said turntable portion of said rotary table apparatus.

5. A method as recited in claim 4 wherein said receptacle is a divot in a surface of said turntable portion shaped to receive said tip of said stylus.

6. A method as recited in claim 3 further comprising placing said tip of said stylus at a fixed center location of said turntable portion of said rotary table apparatus and sampling data from said probe sensors to locate said rotary table apparatus relative to said probe apparatus before said placing of said probe at said fixed location of said turntable portion.

7. A method as recited in claim 3 wherein said receptacle is a divot positioned near a periphery of said turntable portion of said rotary table apparatus.

8. A method as recited in claim 3 further comprising a step of placing said tip of said stylus at an approximately center location of said turntable portion of said rotary table apparatus and sampling a position of said stylus to locate said rotary table apparatus relative to said probe apparatus before said placing of said tip of said stylus at said receptacle of said turntable.

9. A method as recited in claim 2 wherein said probe apparatus is coupled to a computer system to receive said position and orientation data from said probe apparatus, and wherein said sampling is performed by a microprocessor provided locally to said probe apparatus and separate from said computer system.

10. A method for locating the position and orientation of a rotary table apparatus with reference to a probe apparatus for measuring three-dimensional coordinates of a physical object positioned on the rotary table apparatus, the method comprising the steps of:

placing a tip of a stylus of said probe apparatus in a receptacle positioned near a periphery of a turntable of said rotary table apparatus, wherein said probe apparatus includes a linkage of members provided as an arm with said stylus at an end of said arm, said stylus being moveable in a plurality of degrees of freedom;

rotating said turntable about a central axis while said stylus tip is positioned in said receptacle;

sampling a plurality of positions and orientations of said stylus using sensors included in said linkage of said probe apparatus as said turntable is rotated;

sampling an angular position of said turntable about said central axis at each of said sampled plurality of positions and orientations of said stylus, wherein a sensor included in said turntable senses said angular position; and

determining the position and orientation of said rotary table apparatus relative to said probe apparatus utilizing said sampled plurality of positions and orientations of said stylus and said sampled angular positions of said turntable, thereby subsequently allowing a physical object on said rotary table, having its coordinates measured by said probe apparatus, to be rotated on said rotary table during said measuring process.

11. A method as recited in claim 10 wherein said receptacle is a divot shaped to receive said tip of said stylus.

12. A method as recited in claim 11 wherein said turntable is approximately circular, and wherein said turntable is rotated by said user holding said stylus in said receptacle and rotating said turntable while holding said stylus.

13. A method as recited in claim 10 wherein said probe apparatus is coupled to a computer system to receive said positions and orientations from said probe apparatus.

14. A method as recited in claim 13 wherein said step of sampling of said positions and orientations of said stylus is performed by a microprocessor provided locally to said probe apparatus and separate from said computer system.

15. A method as recited in claim 10 further comprising a step of placing said tip of said stylus at an approximately center location of said turntable portion of said rotary table apparatus and sampling a position of said stylus to locate said rotary table apparatus relative to said probe apparatus before said placing of said tip of said stylus at said receptacle of said turntable.

16. A probe system for measuring the three-dimensional geometry of an object and providing information describing said three-dimensional geometry to a host computer system, the probe system comprising:

(a) a probe apparatus including a base and a probe having multiple degrees of freedom, said probe coupled to said base by a plurality of links and joint members such that said probe and each of said links is coupled to at least one of said joint members, said probe apparatus including a plurality of sensors measuring probe data defining a position and orientation of said probe, and wherein said probe is used to physically trace a surface of said object to provide said information describing said three-dimensional geometry to said host computer system;

(b) a rotary table including;

(i) a base;

(ii) a turntable coupled to said base and rotatable about an axis positioned perpendicularly to a surface of said turntable, said turntable for receiving on its surface said object to be measured and allowing a user to move said turntable and said object about said axis during said measuring of said geometry of said object to allow convenient tracing of said surface of said object with said probe; and

(iii) a turntable sensor coupled to said base, said sensor being operative to measure a rotation of said turntable about said axis, wherein said sensor outputs turntable data indicative of said rotation; and

(c) an interface microprocessor separate from said host computer system and coupled to said probe apparatus, said turntable sensor, and said host computer system, said microprocessor being adapted to receive said probe data and said turntable data and providing information derived from said probe data and said turntable data to said host computer system, wherein said turntable data is used to locate said object on said rotary table with respect to said probe after said rotation.

17. A system as recited in claim 16 wherein said probe of said probe apparatus is a stylus having a tip for contacting said object.

18. A system as recited in claim 16 wherein said probe apparatus includes:

a first joint member coupled to said probe;

a first linkage rotatably coupled to said first joint member;

a second joint member rigidly coupled to said first linkage;

a second linkage rigidly coupled to said second joint member; and

a third joint member rigidly coupled to said second linkage and to said base.

19. A system as recited in claim 16 wherein said interface microprocessor is included in said base of said probe apparatus.

20. A system as recited in claim 16 wherein said microprocessor is coupled to a single serial port of said host computer via a serial interface.

21. A system as recited in claim 16 wherein said turntable includes a receptacle positioned near a periphery of said turntable for receiving said probe in an initialization procedure for locating said turntable relative to said probe apparatus.

22. A method for measuring three dimensional geometry of an object using a probe apparatus, where said object is positioned on a rotary table, the method comprising:

providing a probe apparatus on a fixed surface, said probe apparatus including a serial linkage of members coupled to a base, said base coupled to said fixed surface, wherein a stylus for a user to hold is provided at an end of said linkage of members;

providing a rotary table on said fixed surface, said rotary table including a rotatable surface, wherein an object is positioned on said rotatable surface;

measuring coordinates of said object by measuring a location of a tip of said stylus measured with respect to said base of said probe apparatus using sensors included in said linkage of members, said stylus being held by said user to allow said tip to contact a surface of said object when said coordinates are measured;

measuring a rotational motion of said rotatable surface and said object with respect to said base of said probe apparatus using a rotary sensor included in said rotary table; and

continuing to measure coordinates of said object after said rotation by measuring a location of said tip of said stylus with respect to said base of said probe apparatus when said stylus is held by said user such that said tip contacts said surface of said object, said continuation of said measuring of said coordinates being performed without measuring multiple coordinates of said object with said stylus to relocate said object with respect to said base after said rotation.

23. A human computer interface apparatus for allowing a user to manually manipulate a probe within a three dimensional volume while a host computer tracks a position and orientation of said probe with respect to a fixed surface within said volume, said host computer displaying a user-controlled image on a display screen at a position derived from a position of said probe in said three dimensional volume, wherein said interface apparatus allows said probe to be moved in at least five degrees of freedom with respect to said fixed surface, said interface apparatus comprising:

a probe manipulatable by a user;

a support base;

a movable linkage including a first, second, and third joint configuration, wherein said first joint configuration couples said probe to a first link member, allowing said probe to move in two degrees of freedom of rotation with respect to said first link member, said second joint configuration couples said first link member to a second link member, allowing rotation of said first link member with respect to said second link member, and said third joint configuration couples said second link member to said support base, allowing said second link member to move in two degrees of freedom of rotation with respect to said support base;

at least one sensor associated with each of said first, second, and third joint configurations, wherein each of said sensors measures said rotation in a degree of freedom allowed by said joint configurations; and

a microprocessor electrically coupled to said sensors and separate from said host computer system, said microprocessor reading data from said sensors and reporting a representation of said data to said host computer, said microprocessor receiving, decoding, and responding to high level host commands sent from said host computer, wherein said high level host commands include requests to report a single set of said representation of said data, requests to report a repeated stream of said representations of said data over time, and requests to modify parameters stored within memory local to said microprocessor and separate from said host computer.

24. A human computer interface apparatus as recited in claim 23 wherein said image displayed on said display screen is a cursor, said cursor being updated on said display screen in accordance with said position of said probe.

25. A human computer interface apparatus as recited in claim 24 wherein said probe controls a three-dimensional motion of said cursor in a three-dimensional environment displayed by said display screen.

26. A human computer interface apparatus as recited in claim 23 wherein said first joint configuration allows said probe to rotate about an axis passing through a length of said probe, said rotation allowed when said first link member is held fixed with respect to said fixed surface.

27. A human computer interface apparatus as recited in claim 23 wherein said joint configurations allow said probe to rotate about an axis extending through a length of said probe while motion in all other degrees of freedom of said probe is fixed.

28. A human computer interface apparatus as recited in claim 23 wherein said high level host commands include a command to cease reporting said repeated stream of said representations of said data.

29. A human computer interface apparatus as recited in claim 23 wherein exactly one degree of freedom of rotation of said first link member is allowed with respect to said second link member.

30. A human computer interface apparatus as recited in claim 23 wherein said probe includes a switch that can be manually depressed by the user in order to send a command to said host computer.

31. A human computer interface apparatus as recited in claim 30 wherein a signal is sent to said host computer when said switch is manually depressed, sid signal indicating to said host computer of said depressing of said switch.

32. A human computer interface apparatus as recited in claim 23 further comprising a foot pedal manually actuable by said user to send a command to said host computer that allows said user to hold said probe without disturbance when said pedal is actuated.

33. A human computer interface apparatus as recited in claim 23 wherein said third joint configuration includes a counterweight for counterbalancing a weight of said second joint configuration and said first and second linkages.

34. A human computer interface apparatus as recited in claim 23 further including a spring for counterbalancing a weight of said second joint configuration.

35. A human computer interface apparatus as recited in claim 23 wherein said first link member and said second link member are unable to rotate with respect to each other about either of the longitudinal axes extending through a center of each of said first and second link members.

36. A human computer interface apparatus as recited in claim 23 wherein at least one of said joint configurations includes a multistage stop joint which is operative to provide over 360 degrees of rotational movement about an axis to said joint configuration.

37. A human computer interface apparatus as recited in claim 23 wherein said sensor for measuring rotation of one of said degrees of freedom provided by said first joint configuration is positioned within a housing associated with said second joint configuration.

38. A human computer interface apparatus as recited in claim 23 wherein said first joint configuration provides three degrees of freedom of rotation to said probe with respect to said first link member.

39. A human computer interface apparatus as recited in claim 23 wherein said first and second link members are made of graphite.

40. A human computer interface apparatus as recited in claim 39 wherein said graphite is bonded into aluminum members included in said first, second, and third, joint configurations.

41. A human computer interface apparatus as recited in claim 23 wherein said probe is a stylus.

42. A system for measuring spatial coordinates and controlling a cursor displayed on a computer display apparatus, said system comprising:

a host computer for displaying said cursor in a three-dimensional environment displayed on said computer display apparatus, said position of said cursor in said three-dimensional environment being derived from locative data received by said host computer;

an interface apparatus for allowing a user to manually manipulate a probe within a three dimensional volume while reporting said locative data to said host computer, wherein said host computer tracks a position of said probe within said volume using said locative data, and wherein said probe is movable in at least five degrees of freedom with respect to a fixed surface, and wherein user control of said probe in three-dimensional space controls motion of cursor in said three-dimensional environment on said computer display apparatus;

a movable linkage including a first, second, and third joint configuration, wherein said first joint configuration couples said probe to a first link member and allows said probe to move in two degrees of freedom of rotation with respect to said first link member, said second joint configuration couples said first link member to a second link member and allows rotation of said first link member with respect to said second link member, and said third joint configuration couples said second link member to a support base and allows said second link member to move in two degrees of freedom of rotation with respect to said fixed surface;

one or more sensors associated with each of said first, second, and third joint configurations, wherein each of said sensors measures the rotation of a degree of freedom allowed by said joint configuration; and

a microprocessor, separate from said host computer system, for reading locative data from said sensors and reporting a representation of said locative data to said host computer, wherein said host computer manipulates a displayed location of said cursor in response to said reported data, wherein said microprocessor receives, decodes, and responds to high level host commands sent from said host computer, said high level host commands including requests to report data and requests to modify parameters stored within memory local to said microprocessor and separate from said host computer.

43. A system as recited in claim 42 wherein said high level host commands from said host computer to said microprocessor include requests to report a single set of said representation of said data and requests to report a repeated stream of said representations of said data over time.

44. A system as recited in claim 42 including a human computer interface apparatus wherein said first joint configuration allows said probe to rotate about an axis passing through a length of said probe when said first link member is held fixed with respect to said fixed surface.

45. A system as recited in claim 42 wherein said probe includes a switch that can be manually depressed by the user in order to send a command to said host computer.

46. A system as recited in claim 42 wherein said human computer interface apparatus includes a foot pedal that can be manually depressed by the user in order to send a command to said host computer while not disturbing a user'"'"'s ability to hold said probe steady.

47. A system is recited in claim 42 wherein said human computer interface apparatus further includes a counter weight for counterbalancing the weight of said second joint member.

48. A system as recited in claim 42 wherein said human computer interface apparatus further includes a tension spring for counterbalancing the weight of said second joint member.