Design of Low Order Controllers for Robust Disturbance Rejection in Large Space Structures

摘要

This thesis will investigate several issues relating to the objective of improving the disturbance rejection of a Large Space Structure (LSS) type system. Due to properties of LSS systems, the design of the controller must address three main issues: 1) improving of the disturbance rejection properties of the system; 2) insuring that the controller is robust to modeling uncertainty; and 3) implementing the design as a low order output feedback controller. The disturbance rejection of the system will be quantified using the H-norm. An arbitrary level of disturbance rejection will then be achieved through a Linear Quadratic (LQ) minimization. This LQ solution produces a state feedback controller which is robust to modeling uncertainty. In order to realize this design, a low order output feedback controller will be designed based on the LQ solution using projective controls. The method described in this thesis will then be applied to a 40th order LSS example. Using a decentralized approach, a controller will be designed which satisfies the issues discussed above.