Research On Control Methods Of Flexible Solar Array Driving System

Flexible solar array driving system is the research object of this thesis,the method of combining theoretical analysis,digital simulation and simulation experiment is adopted in this paper,which is used in the research of flexible solar array driving system modeling,solar array rotating shaft speed control and solar array elastic vibration suppression.The main research contents are as follows:Firstly,a flexible solar array and a rigid-flexible coupling model of its driving system is established.At first,the small deformation field of the flexible solar array is analyzed.Then according to the situation of its small deformation,the relevant assumptions are proposed before the dynamic modeling of the flexible solar array.After that,Hamilton principle and hypothetical modal method are used to model the flexible solar array dynamically based on these assumptions.Besides,the influence of the additional mass on the flexible solar array is analyzed.Finally,according to the principle of stepping motor and the operating conditions of the solar array,a driving system model is built.Secondly,the features of the flexible solar array driving system is analyzed with the use of digital simulation technology.Mathematica is used to calculate the value of each parameter matrix in the state equation of the solar array,and then a simulation model is established in the MATLAB/Simulink platform according to the modeling principle of the flexible solar array driving system.In the end,related simulation calculations were performed according to the movement conditions of the solar array.Through the simulation calculations,it is found that the system had two typical problems,namely,the large fluctuation of the rotating shaft speed and poor anti-interference ability,and the elastic vibration of the solar array in the process of driving.Thirdly,a current compensation technology based on sliding mode control is designed for the problem of the large fluctuation of the rotating shaft speed and poor anti-interference ability.Through analyzing the system,it is found that the current fluctuation of motor winding has a great impact on the system speed.Thus,in the light of features of the system,a current compensation technology based on sliding mode control is designed.The simulation result shows that it can effectively reduce the fluctuation of the rotating shaft speed and improve its anti-interference ability.Fourthly,a zero vibration and derivative input shaper is designed for the problem of elastic vibration generated by the solar array during the driving process and is used to suppress vibration.First of all,the characteristics of various types of input shapers are analyzed,and then taking an undamped second-order system as an example,the input shaper is designed to illustrate the principle of input shaper restraining linear system vibration.However,because the stepper motor uses a nonlinear method for modeling,the system simulation model is a nonlinear model.It is impossible to use linear system analysis methods to obtain the system frequency and damping ratio,so as to design the input shaper.However,according to the simulation result,it is found that the elastic vibration generated by the solar array during the driving process is mainly affected by the characteristics of the solar array,while the solar array is modeled with the linear system method.That is,although the system has non-linear components,the elastic vibration response is similar to that of a linear system.Therefore,the elastic vibration signal is analyzed to obtain the frequency and damping ratio of the elastic vibration signal.Finally,the simulation experiment proves that the method effectively reduces the elastic vibration generated by the solar array during the driving process.Fifthly,the method of combining digital simulation technology and ground simulation experiment is adopted to analyze the disturbance of the solar array to the spacecraft platform during the driving process.First,based on the model principle,the disturbance torque of the solar array to the spacecraft platform is obtained,and the simulation technology is analyzed.Then the interference signal of the solar array to the platform during the driving process is obtained by conducting ground simulation experiments.Finally,comparing the simulation results with the ground simulation experiment results,the generated disturbance characteristics of the solar array to the spacecraft during the driving process are analyzed.