Research On Orbital Maneuver Control For Satellite With Finite Thrust

Orbital maneuver control for spacecraft is widely used as a mature theory in thefield of spacecraft orbital injection and maintenance. For orbital maneuver theoreticalstudy, the early days focused on the pulse thrust control, but in the process of the actualorbital transfer, thrust amplitude is limited, propulsion is not instantaneous, then finitethrust is widely adopted. As the diversity of the spacecraft mission, requirements forrapid orbital maneuver deserved more and more attention. This thesis, with the satelliteas the study object, research rapid orbital maneuver control under finite thrust. Also, inthe process of orbital transfer, the satellite needs to maintain earth-orientation fortransporting data to ground monitor stations. Therefore, good robust is required for theextern disturbance in the process of orbital maneuver. In addition, the system parameteruncertainty and the saturation nonlinearity of the implementing agencies are also needto be considered. In this thesis, effective control strategies are developed.Firstly, the two-body models of the satellite and the attitude dynamics equationsare established, and then the largest impact on satellite (J2perturbation) is analyzed.Some basic knowledge is introduced for studying the subsequent chapters.Secondly, this thesis transformed the rapid orbital maneuver question into a classof time optimal problem. For distance greater than1km of orbital maneuver, in thegeocentric inertial frame, the orbital maneuver model with J2perturbation is established.Coplanar orbital maneuver and noncoplanar orbital maneuver make the simulation. Fordistance less then1km of orbital transfer, though the introduction of virtual satellite, therelative motion equations of satellite are set up. Orbital maneuver that can provide anydirection of thrust and that only can provide single-axis thrust due to some reasonsmake the simulation. The results show the method is effective.Finally, the thrust misalignment and the center of mass drift in the process of thesatellite orbit transfer have an effect on the satellite attitude. Under the thrustmisalignment and the center of mass drift, saturation nonlinearity of the implementingagencies and parameter uncertainty, two controllers are designed. The first one isadaptive sliding mode controller that based on neural networks. For the upper bounds ofparameters in the actual flight control are difficult to be determined, the adaptive law isdesigned to estimate the upper bounds of the uncertain parameters online. A saturationcompensator based on the ability of universal approximation is developed to overcomethe saturation characteristics of the implementing agencies. Another controller isanti-saturation controller based on the bounded hyperbolic tangent function. L2gain isproposed to suppress interference on the attitude of satellite. The bounded hyperbolictangent function is adopted to meet the bounded control input. Verified by simulation of the two controllers are able to ensure that the satellite can transfer the satellite from oneorbit to another, while maintaining the satellite earth-orientation.