Time-Optimal Manipulator Control for Management of Angular Momentum Distribution during the Capture of a Tumbling Target

Abstract

This paper deals with management problems of angular momentum distribution during the capture of a tumbling target by a free-floating space robot with constraints on the torque and angular momentum that the reaction wheels of the robot are able to output to suppress rotational motion of the robot base. A time-optimal control of the manipulator arm during the approaching phase of the capturing mission and an estimation method to minimize the base rotation after the manipulator captures the tumbling target are proposed in order to realize desirable angular momentum distribution of the entire system. The proposed strategy is verified by numerical simulation with a free-floating space robot model equipped with a 7-d.o.f. manipulator and a system of three reaction wheels.

Avoiding dynamic singularities in Cartesian motions of free-floating manipulators

“…Distributed momentum control has been proposed [20][21][22][23] so that the spacecraft attitude reactions during the approach and postimpact phases are minimized. Several time-optimal control methods have been presented [24][25][26][27], considering either the constraints on the reaction wheel torques or the momentum it can store, along with the constraints on the grasping forces and torques. In all these works, the spacecraft attitude is controlled with the reaction wheel.…”

Kinematic Indices of rotation-floating space robots for on-orbit servicing

“…One can deduce from (8) and (12), the expression of the linear and angular part of the jacobian matrices J 0 q and J 0 r :…”

“…That implies that the relative contributions of the joints and reaction wheels to the base angular motion do not depend on the base inertia but only on the relative angular momentum capabilities of the manipulator and the base spacecraft actuator. This highlights that the distribution of the angular momentum is a critical point to insure the controlability of the system and dedicated control algorithms are required [12].…”

“…The free-floating manipulator kinematic was well known [6] [7], and studies on space manipulator which consider kinetic moment exchange devices are focussed on the compensation of the reaction manipulator torque on the base [8][9] [10].Indeed as satellites integrate such devices to achieve attitude control, these actuators are most of the time controlled separately from the joint manipulator [11] and only few address the issue of the angular momentum distribution of the system [12] and its implication to the base actuators sizing [13].…”

Adaptive robust control for free-floating space robot with unknown uncertainty based on neural network

“…[1][2][3] The FFSR arm movement must cause the coupling motion of the base, and the system is more nonlinear. [4][5][6] In particular, if the influences of uncertainty factors are considered, such as measurement errors, machining accuracy, external interferences, and gear clearances, the precise mathematical model is difficult to get. These problems increase the difficulty of high precision control.…”