Research On Three-degree-of-freedom Helicopter Model Identification And Its Robust Control

With the deployment of military strategy and the needs of production and life,helicopters in military and civilian applications more and.more widely.As a typical representative of the family of helicopters,three DOF helicopter due to its high order,nonlinear,multiple-input multiple-output characteristics and strong coupling,became the ideal object automatic control experiment research.It is very important to study the precise modeling of the three degree of freedom helicopter system and the robust control of the unknown disturbance.Based on the above problems,the system model is identified by the method of system identification.This paper studies from the following aspects:(1)From the hardware structure and software real-time control system of the two aspects of the structure of the introduction,the hardware mainly includes the helicopter body,power control box,control platform and motion control card,the part of the software is the use of the exclusive kernel Matlab/Simulink toolbox Real-Time Workshop for real-time operation;helicopter data flow diagram and working principle diagram describes the working principle of helicopter.(2)Identification of three degree of freedom helicopter model based on PEM.Introduces the basic concepts of system identification;the helicopter model is introduced;in the analysis of coherence function analysis and composite window function are introduced in frequency domain identification theory;prediction error identification method is updated based on subspace identification method,it does not need to provide accurate data,can make accurate prediction of helicopter model;time of flight test is the best verification of the identification model,and the prediction results by time domain flight comparison,proved the accuracy of identification model.(3)Design of adaptive fuzzy H? mixed sensitivity robust controller.The PID controller based on LQR is designed,and the control parameters of PID are determined by LQR;based on the adaptive fuzzy H? mixed sensitivity controller,an indirect adaptive fuzzy controller is designed to approximate the unknown parameters online.In the analysis of weighted function,the H? Mixed Sensitivity Robust control effectively suppresses the interference of the external environment,and the Laypunov theory proves the global stability of the system.Finally,it is proved that the adaptive fuzzy H? hybrid sensitivity controller has better stability and robustness than the PID controller based on LQR.In this paper,the method of prediction error is used to analyze the frequency domain analysis method from the model identification and the design of H? adaptive fuzzy mixed sensitivity robust controller,and the time domain flight test and the actual test are carried out respectively.Finally,it is proved that the model identification method and the robust control method are effective.