Study On Microsatellite Magnetic Attitude Control And Three Axis Passivity Stabilization

Since the concept of microsatellite was proposed in the 80's 20 centuries, its techniques have made great progress in recent years, the development of which is a significant trend in the aerospace area. The microsatellite characterized with light weight, good performance, short development cycle, low cost and its performance can be enhanced greatly by means of constellation or formation flying. As a key section of microsatellite, the microsatellite attitude control system should have the feature of simple configuration, light weight, long working time and high reliability. In this paper, the methods of microsatellite magnetic attitude control and three axis passivity stabilization are studied systemically under the " 863-2 " fund aiding.The microsatellite attitude control system possesses the characteristics of simple configuration, light quality, long working time and high reliability. According to this, the microsatellite magnetic attitude control and three-axis attitude passive stabilization are studied systematically.Through the analysis of the attitude dynamic equation, the potential energy function is derived. The relationships of attitude varieties are derived from energy function and angle momentum equation and thus the attitude control laws of bias momentum satellite are put forward.Through the analysis of the dynamic characteristic of geomagnetic intensity in a orbit, the magnetic dipoles produced by magnetorquer are expanded in Fourier series. The new method of momentum unloading is educed according to the need of the sum of unloaded momentum, and the magnetic dipoles are figured out under the theory of optimal control.According to the direction and damping characteristic of the torque produced by the magnetorquers, the three axis attitude control schemes of gravity gradient satellite and other satellite with damper is presented. The control coefficients are determined by the dynamic characteristics of geomagnetic intensity, so the attitude control precision is improved.According to the direction and damping characteristic of magnetic torque and the theory of linearity, the scheme of satellite attitude control just using magnetic torque is presented.The magnetic attitude control laws for the microsatellite are presented from Lyapunov function and the theory of fuzzy control. The sliding mode function can be educed by constructing a Lyapunov function . and the theory of fuzzy control is used to solve the sliding mode vibration problem.Through the approximate handling of geomagnetic intensity and differential riccati equation, the magnetic attitude H control law of the microsatellite in a circle orbit which has external disturb and the structural perturbation is presented.Through the analysis of attitude dynamic equation, how to realize three axis passivity stabilization of the mircrosatellite by just using environmental torque is presented. Three sortsconformations of three axis passivity stabilization of the mircrosatellite by using environmental torque are put forward, one is to realize the passive attitude control of microsatellite by using the aerodynamic moment and the gravity gradient, the other two by making use of the gravity gradient and the geomagnetic moment, the attitude dynamics of microsatellite of the three sorts are analysed in detail.