Nonlinear programming methods for real-time control of an industrial robot

The optimal control of an industrial robot is considered as a parametric nonlinear control problem subject to control and state constraints. Based on recent stability results for parametric control problems, a robust nonlinear programming method is proposed to compute the sensitivity of open-loop control solutions. Real-time control approximations of the perturbed optimal solutions are obtained by evaluating first-order Taylor expansions of the optimal solutions with respect to the parameter. The proposed numerical methods are applied to the industrial robot Manutec r3. The quality of the real-time approximations is illustrated for perturbations in the transport load.