Locating a workpiece using a measurement of a workpiece feature

• US 9,880,544 B2
• Filed: 05/01/2015
• Issued: 01/30/2018
• Est. Priority Date: 05/01/2015
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Hull, Jerald A., Freeman, Philip L.
• Primary Examiner(s): Tran, Vincent
• Application Number:
  US14/701,937
• Publication Number:
  US 20160318144A1
• Time in Patent Office: 1,005 Days
• CPC Class Codes: G05B 19/401 characterised by control arrangements for measuring, e.g. calibration and initialisation, measuring workpiece for machining purposes G05B19/19 takes precedence
• CPC Class Codes: G05B 19/402 characterised by control arrangements for positioning, e.g. centring a tool relative to a hole in the workpiece, additional detection means to correct position G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/37207 Verify, probe, workpiece

Abstract

A method of determining a pose of a workpiece includes receiving known positions of a plurality of reference features of a workpiece in a first pose in a first coordinate space, determining from the known positions an estimate of the first pose of the workpiece in a second coordinate space in which any pose of the workpiece is defined by six distinct components, and at least one of the six components are known. The method includes receiving a position of a second feature of the workpiece in the second coordinate space when the workpiece is disposed in a distinct, second pose in which the at least one known components remain constant between the first and second pose. The method includes determining the second pose of the workpiece from the first pose estimate and the position of the second feature of the workpiece in the second pose.

Claims

1. A method of performing a machining or manufacturing operation on a workpiece, the method comprising:

a machine tool engaging a workpiece to perform a machining or manufacturing operation on the workpiece; and

a control unit determining a pose of the workpiece, including the control unit at least;

receiving known positions of a plurality of reference features of a workpiece in a first pose in a first coordinate space;

determining from the known positions an estimate of the first pose of the workpiece in a second coordinate space in which any pose of the workpiece including the first pose is definable by six distinct components, at least one of the six components of the first pose being known;

receiving a position of a second feature of the workpiece in the second coordinate space, the workpiece being disposed in a distinct, second pose in which the at least one of the six known components of the first pose are common to the second pose;

determining the second pose of the workpiece from the estimate of the first pose of the workpiece and the position of the second feature of the workpiece in the second pose; and

transmitting the second pose of the workpiece to the machine tool to enable the machine tool to locate the workpiece in the second pose, and thereby enable the machine tool to perform the machining or manufacturing operation on the workpiece based thereon.

2. The method of claim 1, wherein receiving the known positions of the plurality of reference features of the workpiece includes receiving the positions of three discrete reference features of the workpiece.

3. The method of claim 1, wherein the six distinct components include three components of translation and three components of rotation, the three components of rotation including pitch, yaw and roll, and

wherein two of the six components are common to the first pose and the second pose and are the pitch and yaw of the workpiece.

4. The method of claim 1, wherein receiving the position of the second feature of the workpiece in the second coordinate space includes:

receiving a position of the second feature of the workpiece in a third coordinate space; and

translating the position of the second feature from the third coordinate space to the second coordinate space.

5. The method of claim 4, wherein any of the coordinate spaces correspond to at least one of the workpiece, a machine, a machine tool, a workpiece carrier, a change in a pose of the workpiece, and/or a distinct, second pose of the workpiece.

6. The method of claim 1, wherein receiving the position of the second feature of the workpiece includes receiving a measured position of the workpiece, and

wherein determining the second pose of the workpiece includes determining a solution to a system of equations corresponding to a known position of the second feature of the workpiece in the second pose, the measured position of the second feature of the workpiece in the second pose, and a rotation of the workpiece about a longitudinal axis of the workpiece.

7. A machine system comprising:

a machine tool configured to engage a workpiece to perform a machining or manufacturing operation on the workpiece; and

a control unit including at least a processor and a memory storing executable instructions that in response to execution by the processor cause the control unit to at least;

receive known positions of a plurality of reference features of the workpiece in a first pose in a first coordinate space;

determine from the known positions an estimate of the first pose of the workpiece in a second coordinate space in which any pose of the workpiece including the first pose is definable by six distinct components, at least one of the six components of the first pose being known;

receive a position of a second feature of the workpiece in the second coordinate space, the workpiece being disposed in a distinct, second pose in which the at least one of the six known components of the first pose are common to the second pose;

determine the second pose of the workpiece from the estimate of the first pose of the workpiece and the position of the second feature of the workpiece in the second pose; and

transmit the second pose of the workpiece to the machine tool to enable the machine tool to locate the workpiece in the second pose, and thereby enable the machine tool to perform the machining or manufacturing operation on the workpiece based thereon.

8. The machine system of claim 7, wherein the control unit being caused to receive the known positions of the plurality of reference features of the workpiece includes being caused to receive the positions of three discrete reference features of the workpiece.

9. The machine system of claim 7, wherein the six distinct components include three components of translation and three components of rotation, the three components of rotation including pitch, yaw and roll, and

wherein two of the six components are common to the first pose and the second pose and are the pitch and yaw of the workpiece.

10. The machine system of claim 7, wherein the control unit being caused to receive the position of the second feature of the workpiece in the second coordinate space includes the control unit being caused to:

receive a position of the second feature of the workpiece in a third coordinate space; and

translate the position of the second feature of the workpiece from the third coordinate space to the second coordinate space.

11. The machine system of claim 10, wherein any of the coordinate spaces correspond to at least one of the workpiece, a machine, a machine tool, a workpiece carrier, a change in a pose of the workpiece, and/or a distinct, second pose of the workpiece.

12. The machine system of claim 7, wherein the control unit being configured to receive the position of the second feature of the workpiece includes the control unit being caused to receive a measured position of the workpiece, and

wherein the control unit being caused to determine the second pose of the workpiece includes the control unit being caused to determine a solution to a system of equations corresponding to a known position of the second feature of the workpiece in the second pose, the measured position of the second feature of the workpiece in the second pose, and a rotation of the workpiece about a longitudinal axis of the workpiece.

13. A computer-readable storage medium that is non-transitory and has computer-readable program code portions stored therein that, in response to execution by a processor, cause an apparatus to at least:

receive known positions of a plurality of reference features of a workpiece in a first pose in a first coordinate space, the workpiece being engaged by a machine tool configured to perform a machining or manufacturing operation on the workpiece;

determine from the known positions, an estimate of the first pose of the workpiece in a second coordinate space in which any pose of the workpiece including the first pose is definable by six distinct components, at least one of the six components of the first pose being known;

receive a position of a second feature of the workpiece in the second coordinate space, the workpiece being disposed in a distinct, second pose in which the at least one of the six known components of the first pose are common to the second pose;

determine the second pose of the workpiece from the estimate of the first pose of the workpiece and the position of the second feature of the workpiece in the second pose; and

transmit the second pose of the workpiece to the machine tool to enable the machine tool to locate the workpiece in the second pose, and thereby enable the machine tool to perform the machining or manufacturing operation on the workpiece based thereon.

14. The computer-readable storage medium of claim 13, wherein causing the apparatus to receive the known positions of the plurality of reference features of the workpiece includes causing the apparatus to receive the positions of three discrete reference features of the workpiece.

15. The computer-readable storage medium of claim 13, wherein the six distinct components include three components of translation and three components of rotation, the three components of rotation including pitch, yaw and roll, and

wherein two of the six components are common to the first pose and the second pose and are the pitch and yaw of the workpiece.

16. The computer-readable storage medium of claim 13, wherein causing the apparatus to receive the position of the second feature of the workpiece in the second coordinate space includes causing the apparatus to:

receive the position of the second feature of the workpiece in a third coordinate space; and

translate the position of the second feature from the third coordinate space to the second coordinate space.

17. The computer-readable storage medium of claim 16, wherein any of the coordinate spaces correspond to at least one of the workpiece, a machine, a machine tool, a workpiece carrier, a change in a pose of the workpiece, and/or a distinct, second pose of the workpiece.

18. The computer-readable storage medium of claim 13, wherein causing the apparatus to receive the position of the second feature of the workpiece includes causing the apparatus to receive a measured position of the workpiece, and

wherein causing the apparatus determine the second pose of the workpiece causing the apparatus to determine a solution to a system of equations corresponding to a known position of the second feature of the workpiece in the second pose, the measured position of the second feature of the workpiece in the second pose, and a rotation of the workpiece about a longitudinal axis of the workpiece.