Characteristic model and attitude control based on Golden-section control law for small satellite

This paper presents a study of the large angle maneuvers and high-accuracy attitude control of a small satellite which uses a variable inertia reaction wheel(VIRW). Based on the traditional kinetic model of a reaction wheel, a kinetic model of a VIRW with three-axis orthogonal variable inertia is established which takes rotational inertia as the physical variable. A characteristics model of the small satellite attitude motion is then established. This model takes rotational inertia change rate and rotational angular acceleration of the VIRW as a state variable and the satellite attitude angle as the output. The Golden-section control(GSC) law is designed for the attitude control of small satellites, and also tests the function of the control system designed in this paper through simulation. The simulation shows that the small satellite attitude control system based on the VIRW, which uses the GSC law designed in this paper, can achieve a stable control system and smooth transient process. When there is no external perturbed moment, this design won´t produce any steady-state errors, and under the perturbed moment of 20mNm, there will be 0.005° error of attitude angle positioning. The simulation shows a good signal tracking performance under a 5°/s attitude angular velocity.