Optimal placement of piezoelectric actuators based on dynamic sensitivity analysis

Abstract

Positions of actuators play an important role in active vibration control, which affect not only the performance of vibration control but also the stability of whole system, especially for flexible structures. On optimal placement of actuators, many scholars have proposed a variety of optimization criteria, although some of these criteria have generality, but are complex to implement, and the results obtained by using closed-loop design idea to study the optimal placement of actuators are usually affected by initial conditions, the weight matrix and different control laws; which make the problem complicated, and this couldn't improve the effects of vibration control. In fact, before the system design, the initial conditions are difficult to determine, and the placement of the actuators should not affected by initial conditions and control laws, but should only by the inherent characteristics of the system and the external disturbances. In this paper, for a whole-spacecraft vibration isolator using piezoelectric stack actuators, dynamic sensitivity analysis method was used to derive an optimization criteria for piezoelectric stack actuator's placement, this criteria only related to the dynamic characteristics of the structure and the features of disturbance, but wasn't affected by initial conditions and control methods. By using the criteria, optimal placement of the piezoelectric actuators on the whole-spacecraft vibration isolator was studied; simulation results comparison verified the validity of the criteria, and obtained conclusion that different disturbance characteristics and output performances have great effects on the optimal placement.