Integrated structure and control design of actively controlled structures using substructure decomposition

This paper presents a substructuring based approach to the combined structure and control system design problem for flexible space structures. The proposed approach involves decomposing the structure to be controlled into a number of substructures. The substructure information obtained through finite element analysis is synthesized to reconstruct a reduced order model for the entire structure. Two approaches for controller design based on linear quadratic regulator (LQR) theory are proposed. The first approach involves designing a controller for the entire structure obtained by assembling individual substructures. For the second approach, the global controller is obtained by assembling all subcontrollers designed at the substructure level. The integrated control/structure design problem is solved iteratively until a minimum weight design is achieved. A numerical example which compares the results obtained from both the methods with those obtained by directly synthesizing a global controller for the entire structure is presented. The results indicate that both methods proposed herein provide good agreement with the results obtained by analyzing the structure in its entirety.