Application of piezoelectric devices to vibration suppression

Embedded piezoelectric devices may be ideally suited for vibration control of space structures, which lack an inertial ground. When subjected to an input voltage, an embedded piezoelectric actuator changes its dimensions, which in turn generates a pair of forces exerted on adjacent structural members. From the direct piezoelectric effect, an embedded piezoelectric transducer generates an electric charge proportional to the structural dynamic response. In this paper, the implementation, testing, and modeling of an active truss structure with piezoelectric sensors and actuators are described. Linear quadratic Gaussian, second-order, and direct-rate feedback control schemes are designed to suppress the vibrations of the active structure. Simulation and test results are presented. It is shown that special model reduction considerations are required to achieve good correlation between test and analysis. Nomenclature The typical symbology for piezoelectric material properties are used in this paper. Except where noted, the piezoelectric variables are with respect to the standard piezoelectric material 1-2-3 Cartesian coordinate frame. The single, or first of the double, subscript denotes the direction of the applied/sensed electrical field. The second subscript represents the direction of the stress/strain in the piezoelectric material. The subscript r represents the radial direction, as measured in a cylindrical coordinate frame. A = cross-sectional area Ac - controller state matrix As - surface area B, BI = input matrix, /th input matrix Bc = controller input matrix