A new method for simultaneous structural/control optimization

The research involving the coupling of control and structural optimization has met with some difficulties. The new method proposed in this paper optimizes both the structural parameters and time-invariant control gains while including the effects of transient loads. The control force gains are written as explicit functions of the response and are included in the equation of state, which in turn is directly embedded into the augmented performance index. Variations are taken with respect to all of the design variables (state, co-state, structural parameters, and position and/or rate feedback control gains) to generate the governing equations for the system. A computer code was developed to solve the resulting equations and simultaneously solve for the optimal control gains and structural parameters using gradient-based search techniques. The resulting structure is optimal for the specified service environment (initial conditions and/or transient loads) with constant control force gains (position and/or rate feedback). Examples illustrating the viability of this approach are presented.