Accession Number : ADA298801

Title :   Radix Systems, Inc. 50 lb. Moving Magnet Actuator Digital Controller - Design and Implementation,

Corporate Author : RADIX SYSTEMS INC ROCKVILLE MD

Personal Author(s) : Chassaing, Charles E. ; Jones, Mark J.

PDF Url : ADA298801

Report Date : OCT 1994

Pagination or Media Count : 62

Abstract : This document discusses the development and testing of a digital feedback controller on the 50 lbf convectively cooled moving magnet actuator. The shaker design and performance without the digital controller are discussed. The purposes of the digital controller are twofold: to flatten the shaker lbf/voltage frequency response and to reduce the total harmonic distortion in the 26 to 200 Hz operating band. The controller makes use of the moving mass acceleration and/or the shaker voice coil electrical current feedback signals to reduce the shaker distortion. Testing of analog feedback control systems on moving coil transducers has shown that reduction in distortion is possible through feedback by increasing the open loop gain of the system at the drive frequency harmonics. A digital controller provides increased flexibility in the choice of compensation for the feedback, and unlike analog compensation which is hardwired, allows for easy changes to the compensation through software. This is especially significant for shakers used in Naval applications because the frequency response of the shaker is dependent upon the impedance of the structure to which it is mounted; therefore, the feedback compensation also has this dependency. A digital controller also provides the possibility of developing the feedback compensation on- line. With an analog controller, testing must be conducted to determine the shaker frequency response at the mounting location, and then the proper compensation developed off line (for example, in an office with computing facilities) and hardwired in the laboratory. With a digital controller, the system identification and compensation can be determined on line without human intervention.

Descriptors :   *ACTUATORS, *MAGNET COILS, COMPUTER PROGRAMS, CONTROL, DIGITAL SYSTEMS, CONTROL SYSTEMS, ACCELERATION, MASS, HARMONICS, MOTION, VOLTAGE, FEEDBACK, GAIN, MOUNTS, ELECTRICAL IMPEDANCE, DISTORTION, OPEN LOOP SYSTEMS, ANALOG SYSTEMS, FREQUENCY RESPONSE, DRIVES(ELECTRONICS), SHAKING.

Subject Categories : Machinery and Tools

Distribution Statement : APPROVED FOR PUBLIC RELEASE