Apparatuses and systems for finishing three-dimensional surfaces

Patent metadata

Field	Value
Publication number	US-10131033-B2
Application number	US-201414265028-A
Country	US
Kind code	B2
Filing date	Apr 29, 2014
Priority date	Feb 24, 2011
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

A method and an apparatus for smart automation of robotic surface finishing of a three-dimensional surface of a work piece is described. A three-dimensional motion path is created along the surface of the work piece. A variable contact force profile is specified along the three-dimensional motion path. The three-dimensional motion path is modified based on the specified variable contact force profile. The surface of the work piece is finished using one or more surface finishing tools along the modified three-dimensional motion path. The surface of the work piece includes at least a flat region and a curved region.

First claim

What is claimed is:

1. A system for imparting a finish to a three-dimensional surface of a part, the system comprising:
a finishing tool coupled to a movable arm, wherein the finishing tool includes a finishing surface capable of applying a variable contact force against the three-dimensional surface during a finishing operation;
a sensor unit configured to measure an actual force vector associated with applying the variable contact force between the finishing surface and the three-dimensional surface during the finishing operation; and
a controller unit in communication with the sensor unit, the controller unit configured to send a control signal to the finishing tool for controlling a position of the finishing tool during the finishing operation, wherein the controller unit includes a non-transitory computer readable medium including instructions that cause the controller unit to:
determine a nominal path and a target force vector associated with moving the finishing tool along the three-dimensional surface, wherein the target force vector is based on the variable contact force between the finishing surface and the three-dimensional surface,
receive, from the sensor unit, the actual force vector associated with applying the variable contact force against the three-dimensional surface along the nominal path during the finishing operation,
adjust the nominal path, and
provide the control signal to the finishing tool, wherein the control signal is based on the nominal path that was adjusted.

2. The system of claim 1 , wherein the sensor unit includes a multi-axis load cell that measures forces and torques about one or more independent orthogonal axes.

3. The system of claim 1 , wherein the sensor unit includes a single-axis load cell that measures forces along a normal direction with respect to a contacted area of the part.

4. The system of claim 1 , wherein the nominal path is calculated using computer simulated data.

5. The system of claim 4 , wherein the computer simulated data includes calculations of at least one of pressure, contact area, finishing media abrasion properties, finishing media compressibility and conformability, work piece geometry, robotic arm position, or finishing media fluid dynamics.

6. The system of claim 4 , wherein the computer simulated data is based on CAD model data corresponding to a shape of the part.

7. The system of claim 1 , wherein the movable arm comprises a multi-axis robotic arm configured to move in three-dimensions for measuring the actual force vector.

8. The system of claim 1 , wherein the controller unit controls at least one of a position, an angle, a speed of the finishing tool during the finishing operation, or a velocity of the finishing tool during the finishing operation.

9. The system of claim 1 , wherein the controller unit is configured to generate a predicted response time that accounts for a time between measuring the actual force vector and sending the control signal to the finishing tool.

10. A system to impart a finish to a three-dimensional surface of a part, the system comprising:
a positioning assembly configured to position a finishing tool with respect to the three-dimensional surface;
a sensor unit configured to measure an actual force vector associated with applying a variable contact force between a finishing surface of the finishing tool and the three-dimensional surface during a finishing operation; and
a controller unit in communication with the sensor unit, the controller unit configured to send a control signal to the positioning assembly for controlling a position of the finishing tool during the finishing operation, wherein the controller unit includes a non-transitory computer readable medium including instructions that cause the controller unit to:
determine a nominal path and a target force vector associated with moving the finishing tool along the three-dimensional surface, wherein the target force vector is based on a variable contact force between the finishing surface and the three-dimensional surface,
receive, from the sensor unit, the actual force vector associated with applying the variable contact force against the three-dimensional surface along the nominal path during the finishing operation,
in response to determining that the actual force vector differs from the target force vector by more than a tolerance value:
adjust the nominal path, and
provide the control signal to the finishing tool that is based on the adjusted nominal path.

11. The system of claim 10 , wherein the nominal path is calculated based on at least one of force, pressure, contact area, finishing media abrasion properties, finishing media compressibility and conformability, work piece geometry, robotic arm position, or finishing media fluid dynamics.

12. The system of claim 10 , wherein the nominal path compensates for a predicted response time during a subsequent measuring of an actual force vector.

13. The system of claim 10 , wherein the sensor unit includes a multi-axis load cell that measures forces and torques about one or more independent orthogonal axes.

14. The system of claim 10 , wherein the sensor unit includes a single-axis load cell that measures forces along a normal direction with respect to a contacted area of the part.

15. A system for imparting a finish to a three-dimensional surface of a part, the system comprising:
a movable robotic arm coupled to a finishing tool having a finishing surface that is configured to apply a variable contact force against the three-dimensional surface during a finishing operation;
a contact force sensor unit coupled to the movable robotic arm and configured to measure an actual force vector associated with applying the variable contact force between the finishing surface and the three-dimensional surface; and
a controller unit in communication with the contact force sensor unit, the controller unit configured to send a control signal to the movable robotic arm for adjusting a position of the finishing tool during the finishing operation, wherein the controller unit includes a non-transitory computer readable medium capable of executing instructions that cause the controller unit to:
determine a target force vector associated with moving the finishing tool along the three-dimensional surface, wherein the target force vector is based on the variable contact force between the finishing surface and the three-dimensional surface,
measure an actual force vector associated with applying the variable contact force against the three-dimensional surface during the finishing operation,
determine an adjusted target force vector based on a variance between the actual force vector and the target force vector, and
provide the control signal to the finishing tool, wherein the control signal is based on the adjusted target force vector.

16. The system of claim 15 , wherein the non-transitory computer readable medium is further capable of executing instructions that cause the controller unit to:
determine a nominal path associated with moving the finishing tool along the three-dimensional surface.

17. The system of claim 15 , wherein the system is configured to perform at least one of a polishing, lapping, or sanding operation on the three-dimensional surface.

18. The system of claim 15 , wherein the nominal path includes a correction to compensate for a predicted response time during a subsequent measuring of the actual force vector.

19. The system of claim 15 , wherein the contact force sensor unit includes a multi-axis load

Assignees

• Apple Inc

Inventors

• Maloney Max A
• Bujtor Howard E
• Miehm Brian K

Classifications

• B24B27/0038

  with the grinding tool mounted at the end of a set of bars · CPC title

• B24B37/04

  designed for working plane surfaces · CPC title

• B24B49/16

  taking regard of the load · CPC title

• B24B41/068

  Table-like supports for panels, sheets or the like · CPC title

• B24B37/30

  for single side lapping of plane surfaces · CPC title