Study On H_∞Loop Shaping Attitude Control Of A Flexible Satellite

The research object of this paper is the satellites with large solar panels andother flexible accessories. Zero friction problem of zero momentum reaction flywheelbased on the Dahl low speed friction model. Eliminate the zero friction adverseimpacts on the satellite attitude control through the method of zero friction stateobserver design. Considering the uncertainty of system modeling, H-infinity loopshaping controller was designed for the satellite attitude control system simulation.Considering coupling effects brought by the flexible accessories represented bysolar panels and the attitude of the star, the paper establish the dynamic equations offlexible satellite based on Lagrange method. Quaternion and euler Angle methodwere used respectively to describe the body posture, the related parameters of theflexible satellite is presented.Satellite attitude controller PID is designed on the basis of Dahl low speedfriction model of flywheel. the reaction flywheel zero friction negative influence onattitude control of stars was analyzed by numerical simulation. In order to eliminatethe adverse effect, zero friction state observer was designed to compensate the zerofriction. By simulation, illustrates this method can effectively suppress the negativeimpact of the attitude control brought by the zero friction.Aiming at the uncertainty of the flexible satellite system, h-infinity loop shapingcontroller is designed, robust stability analysis was carried out on the controller bythe method of mu analysis. Good robust stability of the controller is shown throughthe numerical simulation results. Based on the flexible satellite control systemsimulation, the following conclusions could be made by the analysis of the result,design of h-infinity loop shaping controller with zero friction compensation method，not only make the system has good robust performance, and control of satelliteattitude control accuracy and stability can reach a high level.