Planning and Control of Two-Link Rigid Flexible Manipulators in Dynamic Object Manipulation Missions

Abstract

This research focuses on proposing an optimal trajectory planning and control method of two link rigid-flexible manipulators (TLRFM) for Dynamic Object Manipulation (DOM) missions. For the first time, achievement of DOM task using a rotating one flexible link robot was taken into account in [20]. The authors do not aim to contribute on either trajectory tracking or vibration control of the End-Effector (EE) of the manipulator; On the contrary, utilizing the powerful tool optimal control accomplishing a point-to-point task for TLRFM is the purpose of the current research. Towards this goal, the pseudospectral method will be developed to meet the optimality conditions subject to system dynamics and boundary conditions. The complicated optimal trajectory planning is formulated as a nonlinear programming problem and solved by SNOPT nonlinear solver. To make robust the response of optimal control against external disturbances as well as model parameter uncertainties, the control partitioning concept is employed. The controlled input is composed of an optimal control-based feedforward part and a PID-based feedback component. The obtained simulation results reveal the usefulness and robustness of the developed composite scheme, in DOM missions.