OPTIMAL MODAL-SPACE CONTROLLER FOR STRUCTURAL DAMPING ENHANCEMENTS

A stochastic optimum-based compensator is developed to enhance structu ral damping with collocated rate sensors/actuators. This controller is based on explicit solutions for the Riccati equations from a modal-sp ace model. The performance of each controlled mode can be easily adjus ted by the corresponding design parameters in the controller. NASA's S pacecraft Control Laboratory Experiment facility is used to demonstrat e the effectiveness of this control design. A distributed-parameter mo del is first obtained by using Holzer's transfer matrix method and the corresponding modal parameters are identified. Then the distributed-p arameter model is reduced to a finite-dimensional modal-space model fo r the controller design. Three torque actuators and three collocated r ate sensors are used to suppress the vibration of the first five modes . Analytical and experimental results show that the proposed controlle r is effective in damping enhancements for large flexible structures.