Abstract: While manipulating a huge transfer vehicle cargo (TVC) in space, shock and impact are inevitable due to its high inertia and velocity and even can influence the safety of the whole system. The Chinese large-scale space end-effector (EER) is developed. Large-tolerance flexible steel cables capture mechanism and the retracting mechanism based on ball screw assembly are designed. The capture sensory system is also presented. According to the characteristics of EER’s mechanism and its working principle, the capture strategy based on Loop/Contact model is proposed. The control strategy decreases the impact to the system dramatically. The dynamic models of EER and TVC under space zero-gravity environment are established. The dynamic equations of EER manipulating TVC in orbit are derived. Computer simulations show that the capture force reduces up to 50% in comparison with that of the traditional method. Experiments demonstrate the capture force is lower than 700 N. Both verify the innovation of the EER mechanism and the feasibility of the control strategy, which has important meaning to EER working stability.

Key words: Capture strategy, End-effector, Loop/Contact model, Transfer vehicle cargo