Robust linear quadratic Gaussian control for flexible structures

A procedure is developed to deal with performance and robustness issues in the design of multiple-input multiple-output compensators for lightly damped flexible structures. The procedure is based upon representing errors in the plant design model as structured uncertainties, and applying a modified linear quadratic Gaussian design method. The cost function in the regulator problem and the process noise model in the estimator problem are varied in a manner that reflects specific parameter uncertainty including frequency, damping, or modal displacement errors. Numerical examples dealing with the control of a large flexible space antenna with uncertain frequencies demonstrate the application of the method.