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

• US 6,078,876 A
• Filed: 10/29/1996
• Issued: 06/20/2000
• Est. Priority Date: 08/07/1995
• Status: Expired due to Term

• Current Assignee: Immersion Corporation
• Original Assignee: Microscribe, LLC
• Inventors: Schena, Bruce M., Rosenberg, Louis B., Brave, Scott B.
• Primary Examiner(s): WACHSMAN, HAL D
• Application Number:
  US08/741,190
• Time in Patent Office: 1,330 Days
• Field of Search: 364/559-564, 364/474.05, 364/474.24, 364/474.37, 364/468.04, 364/468.25, 364/474.03, 364/474.29, 364/474.35, 364/474.36 , 364/571.01, 364/571.02, 364/551.02, 364/505, 364/506, 901/41, 901/15, 901/16, 901/27-29, 345/156-158, 345/161, 345/162, 345/179, 345/184, 345/419, 345/420, 345/423, 33/556, 33/558, 33/559, 33/561, 33/550, 33/555.3, 33/502-505, 33/551, 33/1 M, 33/1 N, 33/1 MP, 33/1 PT, 33/1 CC, 73/866.5, 73/865.8, 73/1.79, 73/1.81, 128/661.04, 128/660.07, 128/660.08, 128/660.09, 395/123, 395/86, 395/89, 395/93, 395/95, 395/99, 395/120, 395/119, 178/18, 82/1.11, 82/1.2, 382/152-154, 382/209, 382/217, 702/33-36, 702/94, 702/95, 702/85-88, 702/104, 702/105, 702/113, 702/115, 702/116, 702/124, 702/126, 702/150-153
• 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 rotary table for use with a three-dimensional digitizing system, said digitizing system including a probe apparatus for measuring three-dimensional coordinates from an object resting on said rotary table, wherein a probe of said probe apparatus is used to physically trace a surface of said object to provide said three-dimensional coordinates to a host computer system, the rotary table comprising:

a support base;

a turntable coupled to said base and operative to rotate about an axis positioned approximately perpendicularly to a surface of said turntable, said turntable for receiving on said turntable surface said object to be measured and allowing a user to move said turntable and said object about said axis during or between said measuring of said coordinates of said object when necessary to allow convenient tracing of said surface of said object with said probe of said probe apparatus; and

a sensor coupled to said support base and operative to measure an angular rotation of said turntable, wherein said sensor provides a signal indicative of said angular rotation to a host computer system, said host computer system being operative to include said angular rotation of said turntable in a determination of the position and orientation of said probe of said probe apparatus with respect to said object on said rotary table when said probe is proximate to said object, said angular rotation being included in said determination when said probe has contacted said object before and after said turntable has been rotated.

2. A rotary table as recited in claim 1 wherein said rotary table further includes interface electronics for providing said angular rotation to said host computer.

3. A rotary table as recited in claim 1 wherein said sensor is positioned near the center of said turntable, and wherein a shaft of said sensor is coupled to said turntable.

4. A rotary table as recited in claim 3 wherein said probe of said probe apparatus is a stylus having a tip for contacting said object.

5. A rotary table as recited in claim 1 wherein said turntable includes a receptacle positioned near a periphery of said turntable for receiving said probe in a, initialization procedure for locating said turntable relative to said probe apparatus.

6. A rotary table as recited in claim 5 wherein said receptacle receives said probe such that when said turntable is rotated in said initialization procedure, said probe rotates with said turntable and a plurality of positions and orientations of said probe are sampled during said rotation to locate said rotary table with respect to said probe apparatus.

7. A rotary table as recited in claim 1 wherein said turntable includes a receptacle positioned near the center of said turntable for receiving said probe in an initialization procedure for locating said turntable relative to said probe apparatus.

8. A rotary table as recited in claim 1 wherein said support base is coupled to a base of said probe apparatus such that a position and orientation of said rotary table is fixed relative to said probe apparatus.

9. A rotary table as recited in claim 1 wherein said turntable includes a first receptacle positioned near a periphery of said turntable and a second receptacle positioned near a center of said turntable, said receptacles for receiving said probe in an initialization procedure for locating said turntable relative to said probe apparatus.

10. A rotary table as recited in claim 1 wherein said turntable is manually rotated by said user to allow said convenient tracing of said surface of said object by said probe.

11. A method for developing a mesh representation of a three-dimensional object by a computer system, the method comprising:

receiving a data point from a probe corresponding to a surface point on a surface of a three-dimensional (3-D) object as a user moves said probe over said surface of said 3-D object;

adding said data point to an end of a current contour line of a mesh representation when said data point is received, said current contour line including a plurality of data points corresponding to surface points on said surface of said 3-D object; and

creating a triangle in said mesh representation when said data point is received and when a previous contour line exists in said mesh representation, said previous contour line being adjacent to said current contour line and including a plurality of data points corresponding to surface points on said 3-D object, said triangle including a data point of said current contour line, a data point of a previous contour line, and a third data point from either said current contour line or said previous contour line.

12. A method as recited in claim 11 wherein said data point of said current contour line, said data point of said previous contour line, and said third data point are chosen based on the distance between data points of said current contour line and data points of said previous contour line.

13. A method as recited in claim 12 wherein said received data point, an index data point of said previous contour line, and a prior data point of said current contour line immediately previous to said received data point are included in said triangle when a distance between said received data point and said index data point is less than the distance between a next data point on said previous contour line immediately following said index data point and said prior data point.

14. A method as recited in claim 13 wherein said prior data point, said index data point, and said next data point are included in said triangle when said distance between said next data point and said prior data point is less than said distance between said received data point and said index data point.

15. A method as recited in claim 12 wherein said previous contour line is adjacent to said current contour line, wherein said data points of said previous contour line have been previously received from said probe.

16. A method as recited in claim 15 wherein said data points of said current contour line and said previous contour line are received successively along each respective contour line.

17. A method as recited in claim 12 wherein said received data point is received by a host computer, and wherein said received data point is provided to said host computer when a user control is activated and when said probe has been traced a minimum distance on said surface of said 3-D object.

18. A method as recited in claim 12 wherein when said received data point is a last data point of said current contour line, a triangle is created for each data point of said previous contour line that is not included in a triangle.

19. A method as recited in claim 12 wherein when said received data point is a second data point of said current contour line, a meshing direction is determined from said previous contour line and said current contour line, said meshing direction indicating from which end of said previous contour line to start creating said triangle.

20. A method as recited in claim 11 further comprising a step of assigning a normal vector to said triangle, said normal vector indicating an exterior surface of said mesh representation, wherein an orientation of said normal vector is based on orientation data included in at least one of said data points of said triangle.

21. A method as recited in claim 11 further comprising a step of displaying said triangle by drawing sides to said triangle between said received data point, said data point of said previous contour line, and said third data point after said triangle is created.

22. A method as recited in claim 21 wherein said triangle and said mesh representation are displayed on a display screen coupled to said computer system.

23. A method as recited in claim 11 wherein said received data point is received by a host computer, and wherein said received data point is provided to said host computer when a user control is activated.

24. A method as recited in claim 11 wherein said received data point is received by a host computer, and wherein said received data point is provided to said host computer after said user manually traces said probe a minimum distance on said surface of said object from a previous location on said surface at which a data point was provided.

25. A method as recited in claim 11 wherein three sides of said created triangle include one side that is a portion of either said current contour line or said previous contour line, and two remaining of said sides are mesh lines connecting said current contour line to said previous contour line.

26. A method as recited in claim 25 further comprising repeating said receiving a data point, said adding said data point to an end of a current contour line, and said creating a triangle in said mesh representation, wherein said triangle created upon said repetition includes one side that is a side of said triangle previously created.

27. A method for providing a selection template for receiving commands from a probe apparatus used for measuring three-dimensional coordinates, the method comprising steps of:

defining a template region within a selected volume as said selection template, wherein a probe included in said probe apparatus is movable within said selected volume;

defining a selection region within said template region and associating said selection region with a command to a host computer coupled to said probe apparatus, said command being used to select a function of said host computer or of said probe apparatus and not being used to determine the position of said stylus; and

providing said command associated with said selection region to said host computer to select said function of said host computer or of said probe apparatus, wherein said command is provided when said probe of said probe apparatus is detected within said selection region.

28. A method as recited in claim 27 wherein a plurality of selection regions are defined within said template region, each of said selection regions being associated with a different command.

29. A method as recited in claim 28 wherein at least one of said selection regions includes indicia describing said command associated with said selection region.

30. A method as recited in claim 29 wherein said indicia in said selection regions include icons and labels.

31. A method as recited in claim 28 wherein said probe apparatus is operative to digitize a three-dimensional object into a geometric representation of said object when said object is traced with said probe, said geometric representation being developed by said host computer from data provided by said probe apparatus.

32. A method as recited in claim 31 wherein said command includes a command to manipulate said geometric representation of said object.

33. A method as recited in claim 32 wherein said geometric representation is a mesh representation.

34. A method as recited in claim 32 wherein said commands include a command to rotate said geometric representation of said object and a command to zoom a view of said geometric representation of said object displayed on said host computer.

35. A method as recited in claim 31 wherein one of said commands is operative to select one of at least two modes of said probe apparatus, wherein said modes determine the manner in which said three-dimensional coordinates are input to said host computer from said probe apparatus.

36. A method as recited in claim 35 wherein one of said modes is autotrigger mode, in which a coordinate is automatically input to said host computer from said probe apparatus at a predetermined distance from a previously input coordinate.

37. A method as recited in claim 31 wherein said commands include a command to save a set of coordinates input to said host computer by said probe apparatus on a storage device, and a command to load a previously stored set of coordinates from said storage device into a memory device of said host computer.

38. A method as recited in claim 27 wherein said stylus has a tip, such that said command is provided to said host computer when said tip of said stylus is detected within said selection region.

39. A method as recited in claim 38 wherein said probe apparatus includes an arm linkage assembly having a plurality of joints and a plurality of linkages connecting said joints, wherein said stylus is positioned at one end of said arm linkage assembly.

40. A method for developing a mesh representation of a three-dimensional object by a computer system, the method comprising the steps of:

receiving a data point from a probe corresponding to a surface point on a surface of a three-dimensional (3-D) object;

adding said data point to an end of a current contour line of a mesh representation, said current contour line including a plurality of data points corresponding to surface points on said surface of said 3-D object; and

creating a triangle in said mesh representation, said triangle including a data point of said current contour line, a data point of a previous contour line, and a third data point from either said current contour line or said previous contour line, wherein said triangle is created only when said current contour line is not the only contour line of said mesh representation, and wherein said received data point, an index data point of said previous contour line, and a prior data point of said current contour line immediately previous to said received data point are included in said triangle when a distance between said received data point and said index data point is less than the distance between a next data point on said previous contour line immediately following said index data point and said prior data point.

41. A method as recited in claim 40 wherein said prior data point, said index data point, and said next data point are included in said triangle when said distance between said next data point and said prior data point is less than said distance between said received data point and said index data point.

42. A method for developing a mesh representation of a three-dimensional object by a computer system, the method comprising the steps of:

receiving a data point from a probe corresponding to a surface point on a surface of a three-dimensional (3-D) object;

adding said data point to an end of a current contour line of a mesh representation, said current contour line including a plurality of data points corresponding to surface points on said surface of said 3-D object; and

creating a triangle in said mesh representation, said triangle including a data point of said current contour line, a data point of a previous contour line, and a third data point from either said current contour line or said previous contour line, wherein said triangle is created only when said current contour line is not the only contour line of said mesh representation, wherein when said received data point is a second data point of said current contour line, a meshing direction is determined from said previous contour line and said current contour line, said meshing direction indicating from which end of said previous contour line to start creating said triangle.