Browse Prior Art Database

COMPENSATING FOR ROBOT Z-AXIS INACCURACIES USING A SYSTEM NON-CONTACT MEASUREMENT

IP.com Disclosure Number: IPCOM000026751D
Original Publication Date: 1993-Jun-30
Included in the Prior Art Database: 2004-Apr-06
Document File: 2 page(s) / 103K

Publishing Venue

Xerox Disclosure Journal

Abstract

Disclosed is a method for improving the accuracy of robotic movement in the vertical direction for robotic applications that require a fixed z-axis position throughout a sequence of robotic movements in a horizontal x and y plane. Since robotic components are temperature dependent and vary during movement in the horizontal plane (x and y axes), robot accuracy specifications do not apply to movements in the vertical direction (along the z-axis). Figure 1 exemplifies the resulting movements 1 or 2 in the vertical direction along the z-axis when a change in position along the x and y axes occurs.

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XEROX DISCLOSURE JOURNAL

COMPENSATING FOR ROBOT Z- INACCURACIES AXIS NON-CONTACT MEASUREMENT USING A SYSTEM
Andrea P. Richardson
Jan J. van der Steen
Mansoor Ghazizadeh

Proposed Classification

U.S. C1.901/014 Int. C1. B25j 11/00

ACTUAL PATH DESIRED

 PATH ACTUAL PATH

i-.

XEROX DISCLOSURE JOURNAL - Vol. 18, No. 3 May/June 1993 331

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FIG. I

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FIG. 2

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COMPENSATING FOR ROBOT Z-AXIS INACCURACIES USING A NON-CONTACT MEASUREMENT SYSTEM (Cont'd)

Disclosed is a method for improving the accuracy of robotic movement in the vertical direction for robotic applications that require a fixed z-axis position throughout a sequence of robotic movements in a horizontal x and y plane. Since robotic components are temperature dependent and vary during movement in the horizontal plane (x and y axes), robot accuracy specifications do not apply to movements in the vertical direction (along the z-axis). Figure 1 exemplifies the resulting movements 1 or 2 in the vertical direction along the z-axis when a change in position along the x and y axes occurs.

The disclosed method for measuring robot z-axis inaccuracies is shown in Figure 2. The method detects and measures, small, unintended z-axis robot movements that occur as a result of motion in the x-y plane, by placing an additional non-contact measurement device at the end of robot gripper 4. Reference sensor 5 is a reflective sensor with a laser light source and sensor arra...