This paper presents a new trajectory generation algorithm for a space manipulator after capturing an uncooperative tumbling target. In particular, the previously developed Adaptive ReactionLess Control algorithm (ARLC) is extended to obtain minimum base reaction motion of the manipulator with consideration of joint limit constraints. A task-priority redundancy resolution technique is formulated within an adaptive control scheme with the primary task to maintain minimum disturbance to the base and the secondary task to avoid the physical joint limits. This control scheme is intended for use in the transition phase of the capture mission from the instant of capture till the unknown parameters are identified and/or the available post-capture stabilization methods can be applied properly. To verify the validity and feasibility of the proposed concept, MSC.Adams simulation platform is employed to implement a planar base-manipulator-target model as well as the three-dimensional model of Engineering Test Satellite VII system. The numerical results show that the proposed control scheme is able to generate the reactionless maneuver without violating joint limits of the arm, after capture of an unknown tumbling target.

This paper presents a new adaptive algorithm to generate reactionless motion for a space manipulator during and after capturing an unknown tumbling target. The intended application scenario is on-orbit servicing whereby the service spacecraft/manipulator system must dock to, or get a hold of the target satellite in order to conduct the required operations. In the course of these missions, it is important to maintain the base attitude of the servicer unchanged. However, the changes in the dynamics parameters of the system, as a result of capturing an unknown target, degrade the performance of the attitude stabilization system. To overcome this problem in the post capture scenario, the adaptive reactionless control algorithm to produce the arm motions with minimum disturbance to the base, without knowledge of target dynamics, is proposed in this study. This algorithm is intended for use in the transition phase from the instant of capture till the unknown parameters are identified and/or the available stabilization methods can be applied properly. The proposed approach is developed based on the momentum conservation of the system, while recursive least squares algorithm is employed for parameter adaptation. To verify the validity and feasibility of the proposed concept, MSC Adams simulation platform is employed to implement a planar base-manipulator-target model. Two basic scenarios are considered: one where the initial (prior to capture) angular momentum of the target is zero and the second where the target is spinning. The numerical results show that the space manipulator is able to perform reactionless motion after capturing an unknown spinning target.