Optimal Open-Loop Control Policies for a Class of Nonlinear Actuators

This paper deals with the design and analysis of open-loop soft-landing control policies for a class of nonlinear actuators. A third-order nonlinear parametric model is firstly presented and the particularities of the systems under study are highlighted. Then, time-optimal and energy-optimal trajectories are analytically derived by means of the Pontryagin principle. Numerical solutions are obtained for a nominal model and the robustness of the obtained open-loop input profiles on perturbed systems is studied via Monte Carlo simulations. The results show that the impact velocities are efficiently reduced with any of the proposed strategies and, consequently, that open-loop control could be a practical and cost-effective approach for improving the performance of these actuators.