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Proceedings Paper

Experiences with integral microelectronics on smart structures for space
Author(s): Ted Nye; Scott Casteel; Sergio A. Navarro; Bob Kraml
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Paper Abstract

One feature of a smart structure implies that some computational and signal processing capability can be performed at a local level, perhaps integral to the controlled structure. This requires electronics with a minimal mechanical influence regarding structural stiffening, heat dissipation, weight, and electrical interface connectivity. The Advanced Controls Technology Experiment II (ACTEX II) space-flight experiments implemented such a local control electronics scheme by utilizing composite smart members with integral processing electronics. These microelectronics, tested to MIL-STD-883B levels, were fabricated with conventional thick film on ceramic multichip module techniques. Kovar housings and aluminum-kapton multilayer insulation was used to protect against harsh space radiation and thermal environments. Development and acceptance testing showed the electronics design was extremely robust, operating in vacuum and at temperature range with minimal gain variations occurring just above room temperatures. Four electronics modules, used for the flight hardware configuration, were connected by a RS-485 2 Mbit per second serial data bus. The data bus was controlled by Actel field programmable gate arrays arranged in a single master, four slave configuration. An Intel 80C196KD microprocessor was chosen as the digital compensator in each controller. It was used to apply a series of selectable biquad filters, implemented via Delta Transforms. Instability in any compensator was expected to appear as large amplitude oscillations in the deployed structure. Thus, over-vibration detection circuitry with automatic output isolation was incorporated into the design. This was not used however, since during experiment integration and test, intentionally induced compensator instabilities resulted in benign mechanical oscillation symptoms. Not too surprisingly, it was determined that instabilities were most detectable by large temperature increases in the electronics, typically noticeable within minutes of unstable operation.

Paper Details

Date Published: 26 May 1995
PDF: 11 pages
Proc. SPIE 2448, Smart Structures and Materials 1995: Smart Electronics, (26 May 1995); doi: 10.1117/12.210461
Show Author Affiliations
Ted Nye, TRW, Inc. (United States)
Scott Casteel, TRW, Inc. (United States)
Sergio A. Navarro, TRW, Inc. (United States)
Bob Kraml, TRW, Inc. (United States)


Published in SPIE Proceedings Vol. 2448:
Smart Structures and Materials 1995: Smart Electronics
Vijay K. Varadan, Editor(s)

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