Browse Prior Art Database

Three-Degree-of-Freedom Active Robotic Final Positioning System

IP.com Disclosure Number: IPCOM000099428D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Document File: 3 page(s) / 61K

Publishing Venue

IBM

Related People

Pinckney, DJ: AUTHOR [+2]

Abstract

Disclosed is a system which enables a robot manipulator to adapt in real time to limited X, Y, and angular (planar) positional changes of objects in its workspace.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 88% of the total text.

Three-Degree-of-Freedom Active Robotic Final Positioning System

       Disclosed is a system which enables a robot manipulator to
adapt in real time to limited X, Y, and angular (planar) positional
changes of objects in its workspace.

      Presently, there are a few techniques which enable a robot
manipulator to adapt in "real time" to positional changes of objects
in their workspace.  These include vision and force feedback systems.
 The disclosed system provides a simple, low cost, non-contact
alternative solution to this problem.

      Figs. 1A and 1B depict the essential elements of the
disclosure.  The application shown is utilized in semiconductor
manufacturing to accurately transfer a silicon wafer from a fixed
pick-up position to a varying drop-off position.  The robot includes
a vacuum paddle 1, used to hold a wafer 2 in place during transport.
Rigidly affixed to the paddle is a sensor bar 3 containing three
solid-state optical switches 4, 5, 6.  One switch is used to define X
location 4, a second for Y 5, and the third for angular (or theta) 6.

      At both the product pick-up and drop-off positions are sensor
interrupt flags 7.  These flags 7 are accurately located with respect
to each position and are designed to fit in the air gap of the
optical switches.

      Final end effector position is determined at both product
pick-up and drop-off locations via the following procedure as
depicted in Figs.  2A, 2B and 2C.
    1.   R...