Integrated Adaptive Control for Spacecraft Attitude and Orbit Tracking Using Disturbance Observer

This paper addresses the control issue of the integrated attitude and orbit tracking of spacecraft in the presence of inertia parameter uncertainty and spatial disturbance. By considering thruster as the control actuator, the 6-degree-of-freedom integrated model consisting of attitude and orbit dynamics is formulated. Based on the backstepping design, an adaptive control strategy is developed by exploiting a projected disturbance observer that compensates for the dynamics uncertainty and an adaptive algorithm that counteracts the observer error. Moreover, an optimal control allocation solution is employed to get the control command of each thruster. Stability analysis proves that the overall closed-loop system is ultimately bounded. To validate the proposed control, the hardware-in-the-loop experiment examples are conducted on the ground testbed facility. Simulation and experiment results show that the spacecraft/simulator can achieve the trajectory tracking and attitude synchronization simultaneously.