Reconfigurable spacecraft attitude takeover control in post-capture of target by space manipulators

Most current research on reconfigurable control system puts emphasis on reconfiguration for adapting to actuator failures. However, the reconfigurable control system is necessitated for spacecraft attitude takeover control in the application of capturing target spacecraft whose fuel is exhausted to extend its operational lifetime by supplying them propulsion, navigation and guidance services. In this scenario, the capture of target spacecraft by space manipulators will cause a large shift in the dynamics of the service spacecraft. Not only do the mass properties change, but also does the thruster configuration. The changes in the mass, center of mass and inertia of the combined spacecraft will cause changes in the equivalent force exerted by each thruster. In this paper, considering the changes of thruster configuration and the control reallocation, a reconfigurable control system is designed for spacecraft attitude takeover control in post-capture of target by space manipulators in order to adapt to changes in the mass properties. The unknown inertia properties of target spacecraft in the system constitute a formidable technical challenge for controller design. Therefore, a modified adaptive dynamic inverse controller is proposed to provide global asymptotic stability in the presence of model uncertainties and nonlinearities. Moreover, by the null-space intersections control reallocation method, the thrust forces of service spacecraft can be redistributed and satisfy some constraints. Numerical simulations validate the feasibility of reconfigurable spacecraft attitude takeover control with large center of mass shifts and unknown inertia properties.