Design of suboptimal controllers for reduction of vibration and sound radiation of plates using piezoelectric actuators

The work presented in this thesis is addressed to the problem of controlling vibration (active vibration control, AVC) and noise (active structural acoustic control, ASAC) of rectangular plates, using multiple accelerometers and piezoelectric actuators. A coupled structural acoustic model is developed, taking into account the electromechanical dynamics associated to the actuators and the dynamics of the integrators, that convert acceleration measures to velocities. Relying on the suboptimal control technique, a velocity feedback optimal controller is designed. In particular, the types of controller studied are the decentralized velocity feedback with independent gains, the centralized velocity feedback and the decentralized velocity feedback with equal gains. Results and considerations are presented for the reduction of vibration and sound radiation of plates with variable characteristics, dimensions and boundary conditions. Configurations of sensors and actuators in assigned positions are studied. Two optimization approaches based on the use of different performance indexes are presented for vibro-acoustic control problems.