An optimal modal-space controller for structural damping enhancements

A stochastic optimum-based compensator is developed to enhance structural damping with collocated rate sensors/actuators. This controller is based on explicit solutions for the Riccati equations from a modal-space model. The performance of each controlled mode can be easily adjusted by the corresponding design parameters in the controller. NASA´s Spacecraft Control Laboratory Experiment (SCOLE) facility is used to demonstrate the effectiveness of this control design. A distributed parameter model is first obtained by using the Holzer´s transfer matrix method and the corresponding modal parameters are identified. Then the distributed parameter model is reduced to a finite-dimensional modal-space model for the controller design. Three torque actuators and three collocated rate sensors are used to suppress the vibration of the first five modes. Analytical and experimental results show that the proposed controller is effective in damping enhancements for large flexible structures.