Research On Control Of ALPHA Space Solar Power Station Concentrator System

Faced with the energy crisis,many countries and scholars have made space solar power station the focus of their research.Space solar power station of on-orbit operation needs to achieve solar cell array orientation and precise orientation of microwave beam and ground receiving antenna.Therefore,this paper focuses on the research of the precise position and orientation control of space solar power station and the SSPS-ALPHA proposed by Prof.Mankins is the study object.Considering the influence of the space environment on the stable operation of the ALPHA concentrator system,the concentrator system mathematical model was used to describe the relationship between the control torque and attitude information,and the attitude determination system was used to measure the concentrator attitude information and fed back to the attitude control system,and then output control torque to overcome the space environmental interference,in order to achieve a stable control of the concentrator system.Therefore,the closed-loop concentrator system design is studied from the controlled object model,space environment,attitude determination system,and attitude control system.The specific work content is as follows:1.The concentrator system mathematical model can be described by the kinematics equations and attitude dynamics equations.Based on the coordinate system construction and the Euler angle description method,the kinematics equations are obtained.The system parameters are also analyzed by the numerical analysis method and the momentum moment theorem is combined with the attitude dynamics equation to depict the control moment and attitude angle information.2.For the influence of the factors of space perturbation on the stable operation of the concentrator system,by analyzing and studying various perturbation and interference models,the paper calculates the gravity gradient,the solar light pressure and the ground shadow respectively,and finally obtains the concentrator system disturbance torque model of the ‘sunlight pressure moment +1000N.m random interference'.3.Establish a posture determination system.Through comprehensive analysis and comparison of sensors used in space missions,this paper uses a high-precision ‘star sensor + fiber optic gyro' combination method as the attitude measurement device.Considering that the attitude sensor itself is accompanied by the interference of uncertain factors,based on the state estimation method,the extended attitude Kalman filter algorithm and the unscented Kalman filter algorithm are used to design the attitude estimator,and the simulation results are studied.Attitude determination algorithm design has feasibility and good state estimation performance,and the accuracy of the unscented Kalman filter algorithm over the extended Kalman filter algorithm is as high as one order of magnitude.4.For the design of the attitude control system,this paper first proposes the equivalent mathematical model of the zero-momentum reaction flywheel to describe the process characteristics of the actuator's recurring control commands.Subsequently,PID control algorithm,fuzzy PID control algorithm,BP neural network control algorithm and sliding film variable structure control algorithm were respectively used to design the attitude controller,and Simulink module simulation was used to verify that the four control algorithms meet the concentrator system performance index requirements.Based on the simulation results of the four control algorithms,this paper finally selects the sliding mode variable structure controller with the best control effect to realize the controlled position and position control of the controlled system.