Truss Structures with Piezoelectric Actuators and Sensors

There are two possible ways of dealing with flexibility in a structure: use stiffer structural members, which increase weight, or augment the inherent damping in the structure. Due to weight restrictions, only the second approach is feasible. In this article, the analytic and experimental development for the active vibration suppression of a flexible truss structure with piezoelectric actuators and sensors is explained. The structure is said to be smart, as it incorporates sensors, actuators and the intelligence to react to disturbances. Finite element modelling and modal decomposition techniques are used to obtain an accurate model of the complex dynamics. The relations that govern the response of the piezoelectric sensors and the influence of the piezoelectric actuators are derived. These relations are presented in such a way that they are easily integrated into the finite element modelling framework. Piezoelectric actuators and sensors are used as components of an active control system for the truss structure that is designed using robust H∞ optimal control theory. Stimulations are performed on both the open and closed loop dynamics to assess the amount of additional damping obtained by the active control system. Simulation results show that the controller significantly increases the damping of the structure. The active controller has been implemented on an experimental truss structure. The experiments performed on the structure closely matched the simulation results. Keywords: Active vibration control; Flexible structures; Piezoelectric materials; organization; Smart structures; Truss structure configuration; Model analysis; Actuator; Sensors; Piezoelectric actuator; Model construction; Vibration suppression; Impact test; Shaker test