INTEGRATED OPTIMIZATION OF STRUCTURES AND LQR CONTROL SYSTEMS FOR REDUCED ORDER MODELS

Abstract

Abstract In this study, integrated optimum design of structures and control systems is studied by using reduced order models. The structures and controllers are optimized simultaneously and successively. Since the degree-of-freedom (DOF) for structures is very large in practice, model order reduction techniques have to be employed at every controller design iteration during optimization in integrated optimum design approaches, that increase the CPU time and involves modeling errors. In this study, Subspace Based Identification (SBI) method is used as a model order reduction technique in frequency domain. It is shown that simultaneous optimization of structures and controllers by using LQR formulations can be achieved by an equivalent decoupled optimization problem where structures are optimized by shaping the structural singular values and following any control law of interest can be designed. Decoupled optimization of structures and controllers has certain advantages, especially for structures having large DOF.