Active Structures for Vibration Suppression and Precision Pointing

This paper describes the work performed at ULB for the development of active structures for space applications, using the piezoelectric technology. The control strategy involves two embedded control loops. The inner loop consists of a decentralized active damping using colocated actuator‐sensor pairs and control schemes with guaranteed stability properties. The outer loop consists of a pointing or position control using non‐colocated actuators and sensors. Two examples of active damping are presented: a truss with linear actuators and a plate with piezo strips. Next, a position control is developed for the truss. The control law is derived from the frequency‐shaped LQG methodology, using a simplified model of the actively damped structure; the band‐width of the control system includes the first two flexible modes of the structure. It is demonstrated that the active damping improves substantially the performance and the robustness of the position control loop, inside and outside its bandwidth. Copyright © 1995 John Wiley & Sons, Ltd