US6134506A — Method and apparatus for tracking the position an…

Claim 1

Independent Claim 296 words

A method for calibrating a probe apparatus which provides three-dimensional position and orientation data to a computer system, said probe apparatus including a probe coupled to a mechanical linkage assembly including a plurality of joints, said mechanical linkage assembly being supported by a support base, wherein said probe is moveable within a selected volume, and wherein sensors coupled to said mechanical linkage assembly are operative to sense joint angles related to a position and orientation of said probe and provide joint angle data to said computer system, the method comprising: (a) positioning said probe such that a known point on said probe is located at an arbitrary location within said selected volume with respect to said support base; (b) varying an orientation of said probe to move a plurality of joints of said mechanical linkage assembly while maintaining said known point on said probe at said arbitrary location; (c) sampling sets of data at a plurality of orientations of said probe as said orientation of said probe is varied about said arbitrary location, said sets of data being provided by said sensors and describing different configurations of angles of said joints; (d) determining a set of spatial coordinates for said known point on said probe at each of said plurality of orientations of said probe; (e) determining a plurality of error, values each error value being between said set of said spatial coordinates determined for each of said plurality of said orientations of said probe and at least one other set of said spatial coordinates; and (f) increasing the accuracy of position and orientation data provided by said probe apparatus by determining calibration parameters based on said error values, said calibration parameters being used when determining said position and orientation of said probe in normal usage.

Claim 2

Independent Claim 296 words

A method for calibrating a probe apparatus which provides three-dimensional position and orientation data to a computer system, said probe apparatus including a probe coupled to a mechanical linkage assembly including a plurality of joints, said mechanical linkage assembly being supported by a support base, wherein said probe is moveable within a selected volume, and wherein sensors coupled to said mechanical linkage assembly are operative to sense joint angles related to a position and orientation of said probe and provide joint angle data to said computer system, the method comprising: (a) positioning said probe such that a known point on said probe is located at an arbitrary location within said selected volume with respect to said support base; (b) varying an orientation of said probe to move a plurality of joints of said mechanical linkage assembly while maintaining said known point on said probe at said arbitrary location; (c) sampling sets of data at a plurality of orientations of said probe as said orientation of said probe is varied about said arbitrary location, said sets of data being provided by said sensors and describing different configurations of angles of said joints; (d) determining a set of spatial coordinates for said known point on said probe at each of said plurality of orientations of said probe; (e) determining a plurality of error, values each error value being between said set of said spatial coordinates determined for each of said plurality of said orientations of said probe and at least one other set of said spatial coordinates; and (f) increasing the accuracy of position and orientation data provided by said probe apparatus by determining calibration parameters based on said error values, said calibration parameters being used when determining said position and orientation of said probe in normal usage.

Claim 3

Dependent Claim 17 words

A method as recited in claim 1 further comprising loading previous calibration parameters from a memory device.

Claim 4

Dependent Claim 26 words

A method as recited in claim 2 wherein said determining a set of spatial coordinates includes adjusting said previous calibration parameters based on said error values.

Claim 5

Dependent Claim 28 words

A method as recited in claim 3 wherein said previous calibration parameters are nominal calibration parameters with assumed ideal values when said probe apparatus is first being calibrated.

Claim 6

Dependent Claim 32 words

A method as recited in claim 4 wherein said adjusted calibration parameters are stored such that said adjusted calibration parameters may be later retrieved and used during operation of said probe apparatus.

Claim 7

Dependent Claim 38 words

A method as recited in claim 5 wherein said adjusted calibration parameters are stored on an EPROM memory device, said EPROM memory device being unable to store data over previously written data stored in said EPROM memory device.

Claim 8

Dependent Claim 58 words

A method as recited in claim 6 wherein said adjusted calibration parameters are stored as a most recent set of adjusted calibration parameters in a specific section of said EPROM memory device such that, when said adjusted calibration parameters are retrieved during operation of said probe apparatus, only said most recent set of adjusted calibration parameters are retrieved.

Claim 9

Dependent Claim 18 words

A method as recited in claim 7 wherein said EPROM memory device is positioned within said support base.

Claim 10

Dependent Claim 75 words

A method as recited in claim 1 further comprising repeating said positioning said probe, said varying an orientation, said sampling, said determining a set of spatial coordinates, and said determining a plurality of error values, said repeating performed when said probe is placed at a location in said selected volume different from said arbitrary location and using said plurality of sampled orientations from said arbitrary location and said different location when determining said error values.

Claim 11

Dependent Claim 20 words

A method as recited in claim 1 wherein said known point on said probe is a tip of said probe.

Claim 12

Dependent Claim 37 words

A method as recited in claim 1 therein said determining a set of spatial coordinates includes using kinematic equations in a mathematical representation of said probe, and wherein said error values represent inaccuracies in said mathematical representation.

Claim 13

Dependent Claim 36 words

A method as recited in claim 11 wherein said calibration parameters are to be used in calculation with said kinematic equations for said probe when determining said position and orientation of said probe in normal usage.

Claim 14

Independent Claim 241 words

A method for zeroing sensors of a probe apparatus of a three-dimensional coordinate measuring system, said probe apparatus including a linkage arm assembly having a probe positioned at a first end, a support base positioned at a second end, and at least five rotary joints positioned between said probe and said support base, said at least five rotary joints being coupled to a plurality of sensors, each sensor operative to measure an angle differential resulting from movement of an associated rotary joint, the method comprising: placing said probe in a receptacle positioned on said probe apparatus, said receptacle being positioned such that when said probe is positioned in said receptacle, four of said at least five rotary joints are substantially fixed in a known angular configuration and wherein a fifth of said at least five rotary joints may be positioned at any rotary position relative to a member coupled to said fifth rotary joint, said known angular configuration being a home position; receiving an indication to zero said sensors of said probe apparatus, wherein said fifth rotary joint is positioned at a particular rotary position relative to said member coupled to said fifth rotary joint when said indication to zero said sensors is received; and assigning a known angle to each of said at least five rotary joints when said probe is positioned in said receptacle, wherein said particular rotary position is considered a known angle for said fifth rotary joint.

Claim 15

Independent Claim 241 words

A method for zeroing sensors of a probe apparatus of a three-dimensional coordinate measuring system, said probe apparatus including a linkage arm assembly having a probe positioned at a first end, a support base positioned at a second end, and at least five rotary joints positioned between said probe and said support base, said at least five rotary joints being coupled to a plurality of sensors, each sensor operative to measure an angle differential resulting from movement of an associated rotary joint, the method comprising: placing said probe in a receptacle positioned on said probe apparatus, said receptacle being positioned such that when said probe is positioned in said receptacle, four of said at least five rotary joints are substantially fixed in a known angular configuration and wherein a fifth of said at least five rotary joints may be positioned at any rotary position relative to a member coupled to said fifth rotary joint, said known angular configuration being a home position; receiving an indication to zero said sensors of said probe apparatus, wherein said fifth rotary joint is positioned at a particular rotary position relative to said member coupled to said fifth rotary joint when said indication to zero said sensors is received; and assigning a known angle to each of said at least five rotary joints when said probe is positioned in said receptacle, wherein said particular rotary position is considered a known angle for said fifth rotary joint.

Claim 16

Dependent Claim 13 words

A method as recited in claim 13 wherein said probe is a stylus.

Claim 17

Dependent Claim 19 words

A method as recited in claim 14 wherein said known angles have previously been calibrated for said probe apparatus.

Claim 18

Dependent Claim 22 words

A method as recited in claim 13 wherein said indication to zero said sensors includes receiving electrical power for said probe apparatus.

Claim 19

Dependent Claim 29 words

A method as recited in claim 13 wherein said receptacle comprises a divot positioned on a joint member rotatable coupled to a grounded joint member of said probe apparatus.

Claim 20

Dependent Claim 37 words

A method as recited in claim 13 wherein said fifth of said rotary joints is coupled to said support base and said fifth rotary joint may be positioned to any rotary position relative to said support base.

Claim 21

Dependent Claim 32 words

A method as recited in claim 13 wherein a local microprocessor performs said zeroing method such that values associated with said at least five rotary joints in said home position are set.

Claim 22

Dependent Claim 28 words

A method as recited in claim 19 wherein said local microprocessor includes setting predefined starting counts associated with said at least five rotary joints in said home position.

Claim 23

Dependent Claim 18 words

A method as recited in claim 20 wherein said predefined starting counts are communicated to a quadrature chip.

Claim 24

Dependent Claim 16 words

A method as recited in claim 13 wherein said linkage arm assembly includes six rotary joints.

Claim 25

Independent Claim 267 words

A method for calibrating a three-dimensional probe apparatus having a probe moveable within a selected volume and a plurality of joints provided in a mechanical linkage coupled to said probe, the method comprising: retrieving calibration parameters from a storage device; sampling a plurality of orientations of said probe as said orientations of said probe are varied at an arbitrary location within said selected volume, wherein a position of a known point on said probe is maintained fixed at said arbitrary location while said orientation of said probe is varied to provide multiple configurations of angles of said joints of said probe apparatus, said sampled plurality of orientations of said probe being sampled from data provided by sensors that detect said joint angles and are coupled to said probe apparatus; using said sampled plurality of orientations of said probe to determine a set of spatial coordinates of said known point on said probe at each of said sampled plurality of orientations; comparing said set of determined spatial coordinates of said known point at each of said sampled plurality of orientations and determining differences between said set of determined spatial coordinates at each of said sampled plurality of orientations and at least one other set of said determined spatial coordinates; and adjusting said calibration parameters based on said determined differences between said set of determined spatial coordinates at each of said sampled plurality of orientations and at least one other set of said determined spatial coordinates such that said adjusted calibration parameters are used when determining a position and orientation of said probe during operation of said probe apparatus.

Claim 26

Independent Claim 267 words

A method for calibrating a three-dimensional probe apparatus having a probe moveable within a selected volume and a plurality of joints provided in a mechanical linkage coupled to said probe, the method comprising: retrieving calibration parameters from a storage device; sampling a plurality of orientations of said probe as said orientations of said probe are varied at an arbitrary location within said selected volume, wherein a position of a known point on said probe is maintained fixed at said arbitrary location while said orientation of said probe is varied to provide multiple configurations of angles of said joints of said probe apparatus, said sampled plurality of orientations of said probe being sampled from data provided by sensors that detect said joint angles and are coupled to said probe apparatus; using said sampled plurality of orientations of said probe to determine a set of spatial coordinates of said known point on said probe at each of said sampled plurality of orientations; comparing said set of determined spatial coordinates of said known point at each of said sampled plurality of orientations and determining differences between said set of determined spatial coordinates at each of said sampled plurality of orientations and at least one other set of said determined spatial coordinates; and adjusting said calibration parameters based on said determined differences between said set of determined spatial coordinates at each of said sampled plurality of orientations and at least one other set of said determined spatial coordinates such that said adjusted calibration parameters are used when determining a position and orientation of said probe during operation of said probe apparatus.

Claim 27

Dependent Claim 72 words

A method as recited in claim 23 wherein said probe apparatus provides three-dimensional position and orientation data to a computer system, wherein said sensors are coupled to said mechanical linkage and are operative to sense said joint angles that are related to said position and orientation of said probe and send joint angle data to said computer system, and wherein said known point on said probe is a tip of said probe.

Claim 28

Dependent Claim 27 words

A method as recited in claim 23 wherein said calibration parameters are nominal calibration parameters with assumed ideal values when said probe apparatus is first being calibrated.

Claim 29

Dependent Claim 32 words

A method as recited in claim 25 wherein said adjusted calibration parameters are stored such that said adjusted calibration parameters may be later retrieved and used during operation of said probe apparatus.

Claim 30

Dependent Claim 19 words

A method as recited in claim 26 wherein said adjusted calibration parameters are stored on an EPROM memory device.

Claim 31

Dependent Claim 109 words

A method as recited in claim 23 further comprising repeating said sampling a plurality of orientations of said probe, using said sampled plurality of orientations of said probe to determine a set of spatial coordinates, and comparing said set of determined spatial coordinates, said repeating performed when the probe is placed at a location in said selected volume different from said arbitrary location and using said plurality of sampled orientations from said arbitrary location and said different location when determining said determined differences between said set of determined spatial coordinates at each of said sampled plurality of orientations and at least one other set of said determined spatial coordinates.

Claim 32

Independent Claim 222 words

A method for zeroing sensors of a probe apparatus of a three dimensional coordinate measuring system, said probe apparatus including a linkage arm assembly having a probe positioned at a first end, a support base positioned at a second end, and N rotary joints positioned between said probe and said support base, wherein N is an integer, said N rotary joints being coupled to a plurality of sensors, each sensor operative to measure an angle differential resulting from movement of an associated rotary joint, the method comprising: placing said probe in a receptacle positioned on said probe apparatus, said receptacle being positioned such that when said probe is within said receptacle, N-1 of said rotary joints are substantially fixed in a known angular configuration, and an Nth rotary joint is substantially free to be positioned at any rotary position relative to a member coupled to said Nth rotary joint; and providing a known angle reference for said sensors when said N-1 rotary joints are in said known angular configuration when an indication to zero said sensors is received, wherein a particular rotary position of said Nth rotary joint relative to said member is considered a known angle for said Nth rotary joint, said Nth rotary joint being positioned at said particular rotary position when said indication to zero said sensors is received.

Claim 33

Independent Claim 222 words

A method for zeroing sensors of a probe apparatus of a three dimensional coordinate measuring system, said probe apparatus including a linkage arm assembly having a probe positioned at a first end, a support base positioned at a second end, and N rotary joints positioned between said probe and said support base, wherein N is an integer, said N rotary joints being coupled to a plurality of sensors, each sensor operative to measure an angle differential resulting from movement of an associated rotary joint, the method comprising: placing said probe in a receptacle positioned on said probe apparatus, said receptacle being positioned such that when said probe is within said receptacle, N-1 of said rotary joints are substantially fixed in a known angular configuration, and an Nth rotary joint is substantially free to be positioned at any rotary position relative to a member coupled to said Nth rotary joint; and providing a known angle reference for said sensors when said N-1 rotary joints are in said known angular configuration when an indication to zero said sensors is received, wherein a particular rotary position of said Nth rotary joint relative to said member is considered a known angle for said Nth rotary joint, said Nth rotary joint being positioned at said particular rotary position when said indication to zero said sensors is received.

Claim 34

Dependent Claim 40 words

A method as recited in claim 29 wherein said member coupled to said Nth rotary joint is said support base, wherein said Nth rotary joint is substantially free to be positioned at any rotary position relative to said support base.

Claim 35

Independent Claim 216 words

A method for zeroing sensors of a probe apparatus of a three dimensional coordinate measuring system, said probe apparatus including a linkage arm assembly having a probe positioned at a first end, a support base positioned at a second end, and a plurality of rotary joints positioned between said probe and said support base, said rotary joints being coupled to a plurality of relative sensors, each of said sensors operative to measure an angle differential resulting from movement of an associated rotary joint, the method comprising: providing an index mark at a predetermined position in a sensing range of each of said relative sensors such that each of said index marks corresponds to a known angle of an associated rotary joint; detecting said index mark for each of said sensors when a user grasps said probe and moves said probe within a workspace, said movement of said probe causing said rotary joints to rotate such that said index mark of each of said sensors is detected; and assigning a predefined reference angle to each of said rotary joints associated with said detected index mark of each of said sensors, wherein said predefined reference angle of each of said rotary joints associated with said detected index mark of each of said sensors is a reference zero angle.

Claim 36

Independent Claim 216 words

A method for zeroing sensors of a probe apparatus of a three dimensional coordinate measuring system, said probe apparatus including a linkage arm assembly having a probe positioned at a first end, a support base positioned at a second end, and a plurality of rotary joints positioned between said probe and said support base, said rotary joints being coupled to a plurality of relative sensors, each of said sensors operative to measure an angle differential resulting from movement of an associated rotary joint, the method comprising: providing an index mark at a predetermined position in a sensing range of each of said relative sensors such that each of said index marks corresponds to a known angle of an associated rotary joint; detecting said index mark for each of said sensors when a user grasps said probe and moves said probe within a workspace, said movement of said probe causing said rotary joints to rotate such that said index mark of each of said sensors is detected; and assigning a predefined reference angle to each of said rotary joints associated with said detected index mark of each of said sensors, wherein said predefined reference angle of each of said rotary joints associated with said detected index mark of each of said sensors is a reference zero angle.

Claim 37

Dependent Claim 47 words

A method as recited in claim 31 wherein said probe is moved by said user from a first location in said workspace to a second location in said workspace, said movement causing said index mark of each of said sensors to be sensed by said associated sensor.

Claim 38

Dependent Claim 18 words

A method as recited in claim 32 wherein said first and second locations in said workspace are predetermined.

Claim 39

Dependent Claim 34 words

A method as recited in claim 31 wherein said movement of said probe in said workspace is a single, fluid motion to cause said index mark of each of said sensors to be detected.

Claim 40

Dependent Claim 248 words

A probe apparatus which provides three-dimensional position and orientation data to a computer system and determines calibration parameters, said probe apparatus comprising: a mechanical linkage assembly, including: a support base provided at a first end of said mechanical linkage assembly for supporting said mechanical linkage assembly; a probe provided at a second end of said mechanical linkage assembly and moveable within a selected volume; a plurality of joints provided between said probe and said support base; and a plurality of sensors coupled to said mechanical linkage assembly operative to sense joint angles related to a position and orientation of said probe and provide joint angle data to said computer system; means for determining a set of spatial coordinates for a known point on said probe at each of a plurality of sampled orientations of said probe when said probe is positioned at an arbitrary location within said selected volume and said orientation of said probe is varied while maintaining said known point on said probe at said arbitrary location; means for determining error values, each of said error values being between said set of spatial coordinates determined for each of said plurality of said sampled orientations and at least one other set of said spatial coordinates; and means for increasing the accuracy of position and orientation data provided by said probe apparatus by determining calibration parameters based on said error values, said calibration parameters being used when determining said position and orientation of said probe in normal usage.

Claim 41

Dependent Claim 248 words

A probe apparatus which provides three-dimensional position and orientation data to a computer system and determines calibration parameters, said probe apparatus comprising: a mechanical linkage assembly, including: a support base provided at a first end of said mechanical linkage assembly for supporting said mechanical linkage assembly; a probe provided at a second end of said mechanical linkage assembly and moveable within a selected volume; a plurality of joints provided between said probe and said support base; and a plurality of sensors coupled to said mechanical linkage assembly operative to sense joint angles related to a position and orientation of said probe and provide joint angle data to said computer system; means for determining a set of spatial coordinates for a known point on said probe at each of a plurality of sampled orientations of said probe when said probe is positioned at an arbitrary location within said selected volume and said orientation of said probe is varied while maintaining said known point on said probe at said arbitrary location; means for determining error values, each of said error values being between said set of spatial coordinates determined for each of said plurality of said sampled orientations and at least one other set of said spatial coordinates; and means for increasing the accuracy of position and orientation data provided by said probe apparatus by determining calibration parameters based on said error values, said calibration parameters being used when determining said position and orientation of said probe in normal usage.

Claim 42

Dependent Claim 188 words

A probe apparatus which provides three-dimensional position and orientation data to a computer system and zeroes transducers of the apparatus, the probe apparatus comprising: a mechanical linkage assembly, including: a support base provided at a first end of said mechanical linkage assembly for supporting said mechanical linkage assembly; a probe provided at a second end of said mechanical linkage assembly and moveable within a selected volume; N rotary joints positioned between said probe and said support base, wherein N is an integer; and a plurality of sensors coupled to said mechanical linkage assembly, each sensor operative to measure an angle differential resulting from movement of an associated rotary joint; a receptacle positioned on a joint member rotatably coupled to said support base of said probe apparatus such that when said probe is positioned in said receptacle, N-1 of said rotary joints are substantially fixed in a known angular configuration, and an Nth rotary joint is substantially free to be positioned at any angular position; and a device that provides a known zero angle reference for said sensors when said N-1 rotary joints are in said known angular configuration.

Claim 43

Dependent Claim 188 words

A probe apparatus which provides three-dimensional position and orientation data to a computer system and zeroes transducers of the apparatus, the probe apparatus comprising: a mechanical linkage assembly, including: a support base provided at a first end of said mechanical linkage assembly for supporting said mechanical linkage assembly; a probe provided at a second end of said mechanical linkage assembly and moveable within a selected volume; N rotary joints positioned between said probe and said support base, wherein N is an integer; and a plurality of sensors coupled to said mechanical linkage assembly, each sensor operative to measure an angle differential resulting from movement of an associated rotary joint; a receptacle positioned on a joint member rotatably coupled to said support base of said probe apparatus such that when said probe is positioned in said receptacle, N-1 of said rotary joints are substantially fixed in a known angular configuration, and an Nth rotary joint is substantially free to be positioned at any angular position; and a device that provides a known zero angle reference for said sensors when said N-1 rotary joints are in said known angular configuration.

Claim 44

Independent Claim 194 words

A method for zeroing sensors of a probe apparatus of a three-dimensional coordinate measuring system, said probe apparatus including a linkage arm assembly having a probe positioned at a first end, a support base positioned at a second end, and at least five joints positioned between said probe and said support base, said at least five joints being coupled to a plurality of sensors, each sensor operative to measure an angle differential resulting from movement of an associated joint, the method comprising: placing said probe in a receptacle positioned on said probe apparatus, said receptacle being positioned on a joint member rotatably coupled to a grounded joint member of said probe apparatus such that when said probe is positioned in said receptacle, four of said at least five joints are substantially fixed in a known angular configuration and wherein a fifth of said at least five joints may be positioned at any angular configuration, said known angular configuration being a home position; receiving an indication to zero said sensors of said probe apparatus; and assigning a known angle to each of said at least five joints when said probe is positioned in said receptacle.

Claim 45

Independent Claim 194 words

A method for zeroing sensors of a probe apparatus of a three-dimensional coordinate measuring system, said probe apparatus including a linkage arm assembly having a probe positioned at a first end, a support base positioned at a second end, and at least five joints positioned between said probe and said support base, said at least five joints being coupled to a plurality of sensors, each sensor operative to measure an angle differential resulting from movement of an associated joint, the method comprising: placing said probe in a receptacle positioned on said probe apparatus, said receptacle being positioned on a joint member rotatably coupled to a grounded joint member of said probe apparatus such that when said probe is positioned in said receptacle, four of said at least five joints are substantially fixed in a known angular configuration and wherein a fifth of said at least five joints may be positioned at any angular configuration, said known angular configuration being a home position; receiving an indication to zero said sensors of said probe apparatus; and assigning a known angle to each of said at least five joints when said probe is positioned in said receptacle.

Claim 46

Dependent Claim 25 words

A method as recited in claim 37 wherein said receptacle comprises a divot positioned on said joint member rotatably coupled to said grounded joint member.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2003-10-17	2004-04-17	2004-10-17	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2007-10-17	2008-04-17	2008-10-17	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2011-10-17	2012-04-17	2012-10-17	$7700.00	Window Closed / Lapsed

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

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