DESIGN OF DYNAMIC DISSIPATIVE COMPENSATORS FOR FLEXIBLE SPACE STRUCTURES

Control system design is considered for attitude control and vibration suppression of flexible space structures. The problem addressed Is th at of controlling both the zero-frequency rigid-body modes and the ela stic modes. Model-based compensators, which employ observers tuned to the plant parameters, are first investigated. Such compensators are sh own to generally exhibit high sensitivity to the knowledge of the para meters, especially the elastic mode frequencies. To overcome this prob lem, a class of dynamic dissipative compensators is nest proposed whic h robustly stabilize the plant in the presence of unmodeled dynamics a nd parametric uncertainties. An analytical proof of robust stability i s gh en, and a method of implementing the controller as a strictly pro per compensator is given. Methods of designing such controllers to obt ain optimal performance and robust stability are presented Numerical a nd experimental results of application of the methods are presented, w hich indicate that dynamic dissipative controllers can simultaneously provide excellent performance and robustness.