In this article, a new adaptive coordinated motion control approach is introduced for a dual-arm free-floating space robot. This adaptive algorithm is used for the post-capture of a large noncooperative target with joint-limit avoidance and uncertain dynamic parameters. To overcome the problem of dynamics coupling between the space base, its manipulators, and the target, we develop a dual-arm space robotic system. One arm is used to complete the capture task and the other is used to counteract the disturbance to the space base. In this case, a new coordinated motion control law is derived based on reaction null space control. An improved joint-limit avoidance algorithm is implemented for large noncooperative target capture; otherwise, a significant base disturbance may result if the joint-limit constraints are not explicitly considered. Based on momentum conservation, the linear regression form of the estimation problem is obtained, and we further identify the unknown inertial parameters of the target. Finally, the simulation results demonstrate the effectiveness of the proposed algorithm.
Abstract
In this paper, the kinematics and dynamics of a free-floating space robot system with prismatic joint are analyzed, and it is shown that the Jacobian matrix and the dynamic equations of the system cannot be linearly parameterized. With the augmentation approach, we demonstrate that the augmented generalized Jacobi matrix and the dynamic equation of the system can be linearly dependent on inertial parameters. Based on the results, the composite adaptive control scheme for a free-floating space robot with unknown inertial parameters to track the desired trajectory in workspace is proposed, and a two-link planar space robot system with prismatic joint is simulated to verify the proposed control scheme.
Coordinated motion control of a dual-arm space robot with joint-limit avoidance and uncertain inertial parameters