Anti-torque-windup control and vibration suppression of flexible-joint dual-arm space robot with an attitude-controlled base

The paper studies the anti-torque-windup control and flexible vibration suppression problems on the coordinated positioning of the base attitude and manipulator joints of a free-floating flexible-joint dual-arm space robot. The full-actuated dynamic equations of flexible-joint dual-arm space robot with an attitude-controlled base are derived by using the linear momentum conservation and Lagrange method. With the flexibility compensating and singular perturbation technology, singular perturbation model of the system is obtained. To suppress the joint flexible vibration of two arms, a torque differential state feedback control strategy is presented for the fast subsystem. Meanwhile, an anti-torque-windup control method based on the torque active constraint design is proposed for the slow subsystem to track the desired positions of the base attitude and joints, and then the control saturation problems of the actual base attitude control system and joint motors are avoided. The obtained simulation results show that the proposed control scheme can accurately position the base attitude and two arms' joint, suppress the flexible vibration of joints and limit the output amplitude of the actual control torques effectively.