High precision dynamic model and control considering J2 perturbation for spacecraft hovering in low orbit.

• This paper does not linearize or average orbit parametersfor J 2 perturbation. • Gauss's variation equations and the coordinate transformation method are combined. • The open-loop control of spacecraft hovering with J 2 perturbation is derived. • A closed-loop controller that keeps the spacecraft hovering state stable is obtained. For spacecraft hovering in low orbit, a high precision spacecraft relative dynamics model without any simplification and considering J 2 perturbation is established in this paper. Using the derived model, open-loop control and closed-loop control are proposed respectively. Gauss's variation equations and the coordinate transformation method are combined to deal with the relative J 2 perturbation between the two spacecraft. The sliding mode controller is adopted as the closed-loop controller for spacecraft hovering. To improve the control accuracy, the relative J 2 perturbation is regarded as a known parameter term in the closed-loop controller. The external uncertainty perturbations except J 2 perturbation are estimated by numerical difference method, and the boundary layer method is used to weaken the impact of chattering on the sliding mode controller. The open-loop control of spacecraft hovering with the relative J 2 perturbation and without the relative J 2 perturbation are simulated and compared, and the results prove that the accuracy of open-loop control with relative J 2 perturbation has been significantly improved. Similarly, the simulation of the closed-loop control are presented to validate the effectiveness of the designed sliding mode controller, and the results demonstrate that the designed sliding mode controller including the derived relative J 2 perturbation can guarantee the high accuracy and robustness of spacecraft hovering in long-term mission. [ABSTRACT FROM AUTHOR]