Coordinated Control of a Dual-arm Space Robot to Approach and Synchronise with the Motion of a Spinning Target in 3D Space

Abstract The non-cooperative objects in space such as space debris and spinning defunct satellites have attracted significant attention because of the rapid development of space exploration. To approach and capture the spinning targets in 3D space, the dual-arm space robot could be more efficient and safer than single-arm space robot to carry out the complicated tasks for spinning targets. The paper extends the model of a dual-arm space robot with Reaction Wheels into 3D space, which is more realistic in practice. The desired trajectories for end-effectors of the space robot are designed to securely approach and prepare to capture the spinning object through synchronising with the grasp points, while at the same time the desired attitude of the base could be maintained. Then coordinated control of the base and end-effectors could be carried out by Nonlinear Model Predictive Controller (NMPC) and a state feedback controller called Direct Parametric Method (DPM) with the consideration of the uncertainties of the space robot system. NMPC has performed with a higher accuracy than DPM without the uncertainties of the space robot system. Considering the imperfect knowledge of the mass and inertia as the uncertainties, NMPC could hold the accuracy of tracking error at the same level of accuracy, but the DPM has showed the poor robustness and downgraded performance in the presence of uncertainties.