Large angle maneuvers of spacecraft based on singularity avoidance of SGCMGs

Attitude control is investigated for a rigid spacecraft using single gimbal control moment gyros(SGCMGs) as actuators. By taking spacecraft and SGCMGs as a whole system, the combined dynamics of SGCMGs and spacecraft are fully considered. The singularity problem of the SGCMGs is converted into the problem of state constraints and input constraints, by so doing the actuation capacity of the SGCMGs is fully utilized. To ensure accurate real-time computation, Gauss Pseudospectral Method(GPM) and Sequential Quadratic Programming(SQP) are used to solve the attitude path planning of the system. Finally, considering the uncertainties of the disturbance torques and the estimation error of the inertia matrix, feedback control of the system is designed by using nonlinear model predictive control(NMPC). Simulation results show good tracking performance and robustness of the designed controller. The modeling method and the control method given in the paper provide a solution to the singularity problem of the SGCMGs.