Research On Adaptive Attitude Control Method Of Aircraft

Since the birth of modern aircraft,scholars from various countries have never stopped studying their attitude control methods.From the initial goal of flying to the current goal of fast and stable flight,from flying in the atmosphere visible to the naked eye to flying back and forth between the aerospace domains,regardless of the shape,performance,function and range of the aircraft,the aircraft Compared with the previous moment,the development of the company may have a qualitative leap.With the continuous development of aircraft,its attitude control technology also needs to keep pace with the times.This paper studies the attitude control technology of axisymmetric aircraft that can achieve cross-domain flight.The flight environment involved in the article is only in the atmosphere,and only the attitude control under the action of aerodynamic forces is studied.For a high-speed aircraft,it will be affected by strong aerodynamic forces during the flight,so fo r a large aspect ratio aircraft,it will produce strong elastic deformation.This interference will act on the control system along with the measurement result of the sensor,which will have a serious impact Time will cause the aircraft to lose control,so this article also makes a corresponding research on the attitude control of the aircraft when there is elastic interference.Based on the existing adaptive control theory,this paper designs and studies an effective aircraft adaptive attitude control meth od in view of the characteristics of parameter uncertainty and large variation range during the flight of the aircraft.First of all,this article introduces the development of adaptive control and the current research status of aircraft attitude control i n the introduction,and leads to the main content of the research.Secondly,the aircraft is mathematically modeled and the attitude feedback tracking control system is designed.First,simplify the aircraft motion model according to the conditions,and give the linearized model of the aircraft,and then establish the block diagram of the attitude control system for each channel.The controller is designed using classical frequency design method,and the Bode diagram and time domain response diagram are combined to verify the rationality of the design.Third,perform online identification of system parameters.Considering the estimation of the aircraft aerodynamic coefficient,interference and elastic frequency respectively,the observability analysis of the system in each case is carried out.Aiming at the estimation of elastic frequency,EKF,UKF and CKF are designed,and the estimation results of the three filters are simulated and compared.Finally,use the results of system parameter identification to de sign an adaptive control system.Here,adaptive control laws are designed for the pitch,yaw,and roll channels respectively,and then the respective results are combined with the design results of the classical frequency method to obtain a complete adapti ve control law.The final simulation results show that the response speed of tracking attitude angle under adaptive control is faster and the error is smaller,which is better than classical feedback control.