Research On Coordinate Attitude Control For Satellite Formation Based On Fuzzy Logic

Small satellites formation technology gains lots of advantages such as short development cycle, low cost, mass process and emission, and has been widely used in various space missions in recent years, to meet different mission requirements. With space missions become more and more complicate, formation satellite systems are facing new challenges, put forward higher controlling requirements. Under the research background of the satellite attitude formation system, this paper focuses on the attitude coordinated control of the leader-follower spacecraft formation flying(SFF) which consists of the small satellites. Fuzzy control method is combined with the classical control theory for the attitude coordinated controllers design, which makes the controllers more intelligent.This paper introduces several common coordinate systems and conversion methods and between two systems and the mathematical description of the satellite attitude, and also highlights the quaternion description method, establishes the mathematical model of the research object and attitude model of rigid satellite, and a satellite relative attitude kinematics and dynamics equations, as the mathematical research basis for the follow research. Given the limitations of conventional control technology, combined with a more optimized intelligent control technology-- fuzzy control, the article describes the basics of fuzzy theory and gives a fuzzy controller design principles.As the research background is the ideal state of the external environment, when the absolutely desired attitude of the satellite formation is a constant value, the paper gives the design of the classic PD satellite attitude controller. Due to the less convenient of the real-time adjustment of PD controller parameters, design the formation of satellite attitude coordinated controller combined with Mamdani fuzzy logic and classical PD controller, and compared with the classical PD controller in the simulation. The simulation results can be observed that the fuzzy controller in the control performance is slight better than classical PD controller, but because of the design of fuzzy controller is dependent on the accumulation of expert experience, and the effect of the controlling depends on the divide of the membership functions, so the advantage is not obvious.In most cases, the attitude of the satellite formation under the leader-follower mode are very value, which because when the satellite at the space missions, their quality will change and receive a variety of interference from the external environment, these would impact the satellite attitude control. In order to suppress the factors of uncertainty and external disturbance, combined fuzzy sliding mode which has better robustness with fuzzy controller, would further optimize the control system performance.