Flight Hardware Implementation of a Feed-Forward Vibration Control System for Space Flight Cryocoolers
A simple control system using force sensors and non-real time signal processing has been designed and tested which reduces vibration levels to 0.1 Newtons or less at the fundamental drive frequency and the 2nd through the 10th harmonics. The NASA/GSFC control algorithm is briefly discussed.
The control system utilizes a proven radiation hardened flight microprocessor card designed and built for the Cosmic Ray Upset Experiment (CRUX). The card was adapted for use with the NASA/GSFC feed forward non-real time vibration control algorithm. The card design consists of an 8085 microprocessor running at 2 MHz with 8 k of PROM and 8 k of RAM. It has one serial RS-422 UART and one 12 bit analog to digital converter. An auxiliary circuit board was fabricated which contains dual port memory, I/O, and four digital to analog converters. The CRUX and auxiliary circuit card designs are discussed in detail.
The vibration control hardware and software system has been tested on a variety of cryocoolers including a Texas Instrument tactical cryocooler, and Lockheed & Ball long-life cryocoolers. Test results, conclusions and lessons learned from the GSFC test experience are presented.
KeywordsVibration Control Soft Error Single Event Upset Stirling Cycle Auxiliary Circuit
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