Research On Autonomous Orbit Maneuver And Attitude-orbit Coupling System Control Of Remote Sensing Satellite

With the rapid development of commercial aerospace technology,satellites have developed from the early single-satellite technology verification to multi-satellite cooperative application to fulfill the application requirements that can not be achieved by a single satellite,such as rapid observation and reconnaissance,rapid coverage and other tasks.In view of the large number of satellite constellation space missions,it not only increases the orbit control frequency,causing the ground station pressure,but also greatly increases the risk of collision between the satellites.Therefore,autonomous orbit maneuver and attitude-orbit coupling control technology is the key of the remote sensing satellite platform in-orbit flight operations and the research focus of remote sensing satellite at present.In this thesis,the autonomous orbit maneuver and the coupling control of attitude and orbit of remote sensing satellites are discussed and studied comprehensively and systematically,and the complete orbit control algorithm and control scheme of remote sensing satellites are established for the typical orbit control tasks,such as collision avoidance,flying-around,constellation configuration maintenance and orbit transfer.The main contents and research work of this thesis are as follows:Aiming at the problem of satellites collision with multiple constraints,mathematical representation method is adopted to establish the station resources,payload and constellation configuration constraint model,collision avoidance control is designed through the numerical analysis method and the Hohmann theory,the numerical analysis shows the direction and control moment of the optimal orbit control.The control direction in the inertial system is obtained by coordinate transformation,and the reasonable velocity increment is given according to Hohmann's orbit transformation theory.In order to reduce the fuel consumption in the process of collision avoidance,a optimal collision avoidance control method is designed for satellites with multiple constraints,the satellite relative motion model in centroid coordinates is established based on the C-W equation,and the model was mapped to the inertial coordinate system by coordinate transformation,and then the collision avoidance strategy is developed by the constraints of the constraint model.The optimization index of satellite energy,the Hamiltonian function and the state equation are selected to give the velocity increment and direction under the optimal conditions,and achieving the optimal fuel collision avoidance control.The phase control and formation flight control are designed for high precision orbital maneuvering control.A small thrust propulsion system is used to design the phase control.Because of the small thrust of the propulsion system and the long control period,the phase control process is divided into three stages: phase adjustment,phase stable drift and phase braking.Propulsion system will exist installation deviation,which leads to the disturbance torque in the process of orbit control,thus the maximum control time of phase adjustment and braking was given through disturbance torque analysis.Under this constraint,setting the completion days of phase control,Kepler's law is used to calculate the control quantity,meantime reaction flywheel is used to control the attitude in the orbit control process.An adaptive sliding mode control algorithm is designed for high precision formation control.Considering the influence of non-circular orbit and other gravitational perturbation,a relative motion model is established,by model transformation technology to linear this model,on the basis of the model,an adaptive sliding mode controller is designed,using neural network to approximate linearization error and gravity disturbance,The asymptotic stability of the closed-loop tracking system can be guaranteed by using the Lyapunov stability theorem and the positive definite matrix judgment theorem.The orbit control completely depends on the ground station,when the number of satellites increases gradually,it not only increases the burden of daily ground operation,but also increases the pressure of the ground station.Aiming at this problem,an autonomous orbit control strategy is designed.Firstly,the balance arm optimization method is designed to give the optimal installation structure of the propulsion system,and the coupling torque generated by the propulsion system is analyzed.Secondly,an extended Kalman filter(EKF)algorithm is designed to determine the precise satellite orbit,and the EKF model parameters are optimized by GPS observation data.Finally,the phase control strategy is formulated based on the orbit determined by EKF,when the phase threshold is exceeded,the satellite starts to work automatically.Based on the attitude-control thruster structure layout,a multiple pulse attitude control method is designed to solve the attitude disturbance problem in the process of track control,the RBF neural network is used to approximate the coupling torque and disturbance torque in the orbit control process,and the stability of the control system is proved by Lyapunov stability theory.Aiming at the control problem of attitude orbit coupling system,the design of satellite attitude orbit coupling simulation system and the control algorithm are studied.The satellite attitude and orbit coupling control simulation system includes a simulation computer,a onboard computer,a simulation simulator for cross-linked environment,flywheels and a satellite dynamics model.Simulation software is used to model the main components,such as star sensor,fiber optic gyro,propulsion system and GPS receiver.The semi-physical attitude and orbit coupling simulation system is established by connecting the cross-linked environment real-time simulation simulator with the onboard computer.Because of satellite propulsion system installation deviation and thrust vector deviation,it will lead to an unstable attitude in the process of the orbit control,thus an orbit control method is proposed in which the reaction flywheel and propulsion system work together.Based on the satellite attitude and orbit coupling control simulation system,when the attitude deviation angle is small,the reaction flywheel starts to adjust the attitude,when the attitude deviation angle is large,the propulsion system starts to adjust the attitude.Fuel consumption can lead to the change of the center of mass and moment of inertia,affecting the attitude control accuracy,and the satellite will be influenced by all kinds of perturbation forces in the complex space environment.In order to achieve that the orbit and attitude can simultaneously track the desired state with high-precision,an adaptive RBF neural network sliding mode control method with finite force and torque is designed.The fuel consumption rate and the rule of variation of moment of inertia are given by test,then 6 degree of freedom time-varying dynamics model is established,RBF neural network is used to compensate the coupling disturbance torque and space environment disturbance caused by orbit transfer of small satellite,and the stability is proved by Lyapunov theory.