Research automatic stability technology of spacecraft assembly with captured non-cooperative targets on orbit

After capturing non-cooperative targets, the mass properties of the spacecraft change abruptly, which makes the system uncertain and unstable. To avoid excessive interference during the control process, an automatic balancing strategy is proposed which identifies the mass properties of the assembly and then moves the non-cooperative targets. First, the capturing process of non-cooperative targets and the automatic balancing strategy are described. Secondly, based on the theorem of the moment of momentum, the dynamic models of the assembly are generated, and the analytical relationship between the location of the non-cooperative target and the offset of the centroid is derived. Thirdly, based on the information measured by the optical gyros, a nonlinear programming method is used to get the mass properties. Finally, the sliding mode variable structure control theory is used to design the control loop of the non-cooperative targets, while the stability of the system is analyzed by Lyapunov theory. It is demonstrated that the strategy proposed in this paper is effective and suitable for services on-orbit.