Dynamic modeling and control of space manipulator with flexible joints and links

Only joint flexibility or link flexibility is considered in the dynamic modeling of the space manipulator by most researchers, and the assumed mode method, only suitable for small deformation, is usually utilized to describe the flexible deformation of link. Both nature coordinate formulation (NCF) to model the flexible joint and absolute nodal coordinate formulation (ANCF) to model the flexible link are used to obtain the dynamic equations of the space manipulator, which include both joint flexibility and link flexibility and are able to precisely describe both small and large deformations. The joint trajectory is developed by quintic polynomial function, and then the actuator torque is obtained by the inverse dynamics as feedforward. PID control scheme is used as feedback input. The two-link flexible manipulator is used to evaluate this method. Results show that the proposed control scheme is effective in both the tracking of joint trajectory and suppressing of vibration.