Research of capture error and error compensate for space net capture robot

Using flexible net to capture malfunction satellites is more preferable than using rigid mechanisms. However, when the flexible net is ejected directly from the platform without control, capture error will be presented because of the orbital dynamic disturbance. In this paper, the capture net is simplified as a mass point, the capture errors are investigated in local orbital coordinate by using Hill equations. An error compensating control scheme is proposed based on tether tension, whereas this control scheme is proved unfeasibility due to the unstable of the rotation libration. After that a tethered satellite net release strategy is proposed as an alternative method. By employing sub-satellite the capture net is transported near to the target firstly and then to be cast, thus the net free flying distance under the orbital dynamical disturbance is reduced and the capture error is minimized. As a demonstration of this strategy, the sub-satellite release dynamic is established and corresponding nonlinear controller for trajectory tracking is employed, the performance of the trajectory tracking controller is also proved by simulations.