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Proceedings Paper

Compensation for passive damping in a large-amplitude microgravity suspension system
Author(s): Mark C. Anderson; Timothy K. Hasselman; Thomas C. Pollock
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Paper Abstract

ACTA has developed and demonstrated a three-dimensional, large amplitude, actively-controlled, multi-cable suspension system for dynamically testing large space structures in a simulated microgravity environment. Tension in the cables is actively controlled by large amplitude rotary actuators designed and built at Texas A&M University. The actuators passively support the weight of the test article on soft spiral springs. Spring stiffness in each actuator is compensated by a torque- controlled direct current motor. Bearing and brush friction and damping are actively compensated as well as the algorithmic damping induced by the control law. Actuator stiffness properties were determined by measuring the torque- deflection characteristics of the actuator. Hysteresis loops are compared for the different spring materials Actuator friction and damping properties (velocity-dependent resistance) are determined by measuring the torque-speed characteristics of the actuator with the spring disconnected. Multiple tests were conducted to establish the degree of randomness in these characteristics for robust control design. This paper describes the characterization of actuator stiffness, kinetic friction, and damping, and describes how these characteristics are used to negate the resulting resistance torques in the suspension system. Conclusions regarding the effectiveness of the system and possible enhancements are discussed.

Paper Details

Date Published: 9 May 1997
PDF: 12 pages
Proc. SPIE 3045, Smart Structures and Materials 1997: Passive Damping and Isolation, (9 May 1997); doi: 10.1117/12.274204
Show Author Affiliations
Mark C. Anderson, ACTA Inc. (United States)
Timothy K. Hasselman, ACTA Inc. (United States)
Thomas C. Pollock, Texas A&M Univ. (United States)


Published in SPIE Proceedings Vol. 3045:
Smart Structures and Materials 1997: Passive Damping and Isolation
L. Porter Davis, Editor(s)

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