Integrated Structure Decomposition, Optimization and Control Design

In this paper, an integrated optimization, controller design and reduced order finite element modeling based approach is presented for structural design. The proposed approach involves structure decomposition, subcontroller design, system controller assembly, and multiobjective optimization. The concept of structure decomposition with compatible and incompatible interfaces is presented for a control/optimum system problem, and developed for problems with compatible interfaces involving substructure controller design and multiobjective optimization. The substructure information obtained through finite element analysis is synthesized to reconstruct a reduced order model for the entire structure. Based on SSSC (Substructure Synthesis-Substructure Controller), a controller is designed for each substructure. The global controller is obtained by assembling all subcontrollers designed at the substructure level. A multiobjective optimum formulation is presented based on structure decomposition and controller design. Four objective functions are simultaneously optimized. These include a stability robustness index, structural weight, controller energy, and a controller performance index. Numerical examples are presented to demonstrate the effectiveness of the proposed methodology. Results obtained using the proposed approach are compared with those obtained from optimization of the entire structure.