A general control strategy for planar 3-DoF underactuated manipulators with one passive joint

Abstract

This paper presents a general control strategy based on the trajectory planning and tracking control for the planar 3-DoF underactuated manipulators with one passive joint at different position. According to the target position of the system, a set of target angles of all links are quickly obtained by using differential evolution algorithm. In order to achieve the control objective of the system from the initial position to the target position, we design the trajectory for each active link of the system, which is composed of two parts. The first part of the trajectory is designed according to the initial and target angle of the active link. The second part of the trajectory is designed based on the constraints between the passive joint and the active joints. Meanwhile, the parameters of the trajectories are optimized by the differential evolution algorithm to ensure that all links reach to their target angles eventually by tracking the designed trajectories. Then, the sliding mode variable structure controllers are designed to make all active links track their trajectories. The effectiveness of the proposed strategy is demonstrated through simulation results.