Coordinated motion control of a dual-arm space robot with joint-limit avoidance and uncertain inertial parameters

Abstract

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.

Adaptive coordinated motion control with variable forgetting factor for a dual-arm space robot in post-capture of a noncooperative target

“…Special attention must be paid to the dynamic coupling between the space base and its manipulators. The kinematic and dynamic model of a dual-arm space robot has been described in Jiao et al 17,18 For clarification purposes, we recall the process of building the kinematic model here. The body 0 in Figure 1 represents the space base of the space robot, which is connected to two manipulators, each with three links.…”

“…Under Assumption (3), there are no external forces or torques acting on the space robot system; therefore, the linear and angular momentum of the system are conserved, which means ( P , L ) remains constant. With Assumption (3), the initial momentum is zero, and we can obtain the following equation, the elements of the matrix are explicitly described in the study by Jiao et al 18…”

Space robot motion planning in the presence of nonconserved linear and angular momenta

“…In [14] the GJM method was extended to the case of multiarm space robot system, in which one arm is used to keep constant satellite attitude. Other approaches in which one arm of a dual-arm space robot system was used to counteract the disturbance induced by the motion of the other arm on the satellite can be found in [15][16][17]. In [18] the equations of motion of a rotation floating space robot were modified through adding new states representing the kinetic moment exchange.…”