An Universal Control Strategy for Planar 2-DoF Underactuated Manipulator with One Passive Joint

This paper presents an unified control strategy based on the trajectory planning and tracking control for the planar 2-DoF underactuated manipulator. The trajectory of the active link is composed of two parts. The first part trajectories are designed according to the initial and target angles of the active link. The second part trajectories are designed based on the constraints between the underactuated link and the active link. Meanwhile, the parameters of the trajectories are optimized by the differential evolution algorithm (DEA) to ensure all links eventually reach to their target values by tracking the designed trajectories. Then, the sliding mode variable structure controller are designed to make the active link track their trajectories. The effectiveness of such strategy is demonstrated through simulation results.