Browse Prior Art Database

Feedback Position Control

IP.com Disclosure Number: IPCOM000073576D
Original Publication Date: 1971-Jan-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Cary, HB: AUTHOR

Abstract

A positive feed system using P-I-N diodes can be made to give accurate position control. The system uses a light source 1 directed into a target prism 2 which returns the output beam 3 to the mirror 4. The feedback control is obtained by directing the beam 3 onto a P-I-N position detector diode 5 through a focusing prism 6. The target prism 2, the focusing prism 6, and the mirror 4 are mounted on the movable carriage 7 or portion of the machine that is to be precisely positioned. The P-I-N diode 5 is mounted on a fixed portion of the machine as a precision reference device or index. The P-I-N diode-decoder combination shows the actual number of index points that the carriage moving part has traveled.

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Feedback Position Control

A positive feed system using P-I-N diodes can be made to give accurate position control. The system uses a light source 1 directed into a target prism 2 which returns the output beam 3 to the mirror 4. The feedback control is obtained by directing the beam 3 onto a P-I-N position detector diode 5 through a focusing prism 6. The target prism 2, the focusing prism 6, and the mirror 4 are mounted on the movable carriage 7 or portion of the machine that is to be precisely positioned. The P-I-N diode 5 is mounted on a fixed portion of the machine as a precision reference device or index. The P-I-N diode-decoder combination shows the actual number of index points that the carriage moving part has traveled. This value is compared in the comparator 8 with pre-set reference input 9 and fed back to the control circuits which drive the carriage 7. The comparator 8 output need only be plus, minus or equal. In this way, forward, reverse and no movement or stop is directed to the carriage drive circuits. The focusing lens required for the return beam directed to the P-I-N diode detector may be either a triangular prism or a light-pipe type. The triangular prism forms a line of light and the light pipe a small dot of light.

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