Non-contact linear actuator position sensor having a pid-compensating controller

US6246228A · kind A · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• Dean C. Alhorn · Huntsville, US
• David E. Howard · Hazel Green, US

Key dates

• Filing date: Nov 27, 1998
• Grant date: Jun 12, 2001
• Expiry date: Nov 27, 2018

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B7/14
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A position sensor or controller generates a response signal in existing armature windings of an actuator and detects the response signal to determine the position of the armature. To generate the response signal, the actuator includes a sensor excitation winding near the armature. Two sensor excitation windings can be provided, above and below the armature, to cancel out z components and thus allow for a variable gap. The sensor excitation winding or windings are supplied with an excitation signal to induce the response signal in the armature windings. The response signal is derived by differentially amplifying and frequency filtering a raw output of the armature windings. The response signal is demodulated to determine position. If a position controller rather than a mere sensor is desired, the position signal can be buffered, PID compensated, amplified, and fed back to the armature windings.