Browse Prior Art Database

AUTOMATIC CORRECTION OF ROBOT DISPLACEMENT ERRORS

IP.com Disclosure Number: IPCOM000026556D
Original Publication Date: 1992-Oct-31
Included in the Prior Art Database: 2004-Apr-06
Document File: 2 page(s) / 125K

Publishing Venue

Xerox Disclosure Journal

Abstract

A method for automatically correcting displacement errors in robotic systems for part locations accessed by robot arms on assembly trays is disclosed. Part locations on trays are currently set in a robotic system using either a teaching or a framing method. The teaching method involves showing a robotic system where a part is located by moving a robot arm manually to each individual part location and subsequently saving a value representing that location in memory of the robotic system. Time incurred teaching is a major drawback of the teaching method when there are many parts on the assembly trays.

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XEROX DISCLOSURE JOURNAL

AUTOMATIC CORRECTION OF ROBOT DISPLACEMENT ERRORS

Jay A. Glaspy Jr. Marta A. Galuga

Proposed Classification

U.S. C1.318/568.13

Int. C1. B25j 09/22

10 @OOOOOO 000000:

000000 000000

42 - 41 00000

f

50 2---;5 -

---/

7 b-4

FIG. 1

XEROX DISCLOSURE JOURNAL - Vo1.17 No. 5 SeptembedOctober 1992 303

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AUTOMATIC CORRECTION OF ROBOT DISPLACEMENT ERRORS

(Cont'd)

A method for automatically correcting displacement errors in robotic systems for part locations accessed by robot arms on assembly trays is disclosed. Part locations on trays are currently set in a robotic system using either a teaching or a framing method. The teaching method involves showing a robotic system where a part is located by moving a robot arm manually to each individual part location and subsequently saving a value representing that location in memory of the robotic system. Time incurred teaching is a major drawback of the teaching method when there are many parts on the assembly trays.

The framing method however requires that a robotic system is given limited pieces of information, which together are known as a frame. A frame is composed of values describing an x, y plane in which parts lie on assembly trays and a value for the displacement between the parts. Once given a frame, a robotic system is capable of directing its robot to each part on a tray relative to a reference location. Position accuracy is maintained by the robotic system as long as the reference location of the frame is correct. The difference between the true location of a part and the location moved to by the robot relative to a given frame defines a displacement error.

The disclosed method shown in Figure 1 compensates for displacement error for incorrectly defined frames on tray 10 by automatically calculating or inputting manually a...