Controller design for rigid-flexible multibody systems

Controller design for rigid-flexible multibody systems is considered. The importance of full coupling between the rigid and flexible motions in the dynamic model is emphasized. Some computed torque-type controllers for rigid-flexible multibody systems are studied using simulations of a two-link system. It is found that a controller design based on uncoupled equations of motion generally provides good performance when evaluated on a fully coupled simulation model. Evaluating controllers, however, using uncoupled equations in the simulation can give misleading results. Robustness to nonlinearities is investigated, since the computed torque-type control cannot cancel all the nonlinear terms. Uncoupled controllers tend to be more robust than controllers based on linear quadratic design, and of the controllers considered the Corless-Leitmann controller gave the best robustness results for uncancelled nonlinear terms. Spillover and robustness to model parameter uncertainty are also investigated through simulations