Closed-loop identification and compensation for environmental disturbance torques acting on spacecraft

In this paper, disturbance torque identification method was proposed to improve the precise attitude control of three-axis stabilized spacecraft for steady-state operation. Based on output-only data for steady state and the system transfer function, closed-loop identification was used to obtain the complete models of environmental disturbance torque. Meanwhile, the modified eigensystem realization algorithm with data correlation (ERA/DC) and multivariate linear regression method were used to obtain the disturbance model parameters. By choosing feedforward control method, we can achieve on-line compensation for the identified environmental disturbance torques. Simulation results show that the approach can compensate the uncertain environmental disturbance torques effectively, and improve the steady-state precision of spacecraft attitude control system.