Research On Sliding Mode Control For Aircraft Attitude Control Systems

With the rapid development of the aeronautics and astronautics technology, the attitude control of aircraft becomes more and more important, and there are more and higher requirements of stability and pointing accuracy problem of aircraft. Variable structure control with sliding mode (VSS) was firstly proposed by Emelyanov, a Soviet researcher, in the1950s, and then was more developed by Utkin, etc. It has gotten much attention because of its excellent invariance to the change of system parameters, external disturbance, namely complete robustness. During the50years, it has been applied in all sorts of controlling fields, such as robot, technical control, aeronautics and astronautics etc. Based on sliding mode control of the aircraft were studied. The main works are as follows:First of all, the thesis makes some discussion about three kinds of description method of the kinematic model of the attitude, i.e. direction method, Euler method and quaternion method, and makes comparison between advantage and disadvantage. The kinematic equations based on Euler method and quaternion of the attitude are introduced and analyzed in the thesis.Secondly, the thesis makes exact linearization of the mathematical model based on the Euler method and design sliding mode controller, on this basis, for. Linear switching function is chosen in the thesis, and the error between desired output and actual output is used to design sliding surface. In order to ensure the accessibility of sliding mode and the perfect performance of the reaching movement, reaching law method is applied. simulation is made to the control system, and validate the controller by the response figures.Thirdly, take into account the advantage of the global sliding mode variable control: only the sliding mode, but no closer to modality. Based on the equivalent control theory, Chapter â…¤ designs the whole sliding mode controller. The form of the controller is simple, easy to implement and the controller eliminates the traditional sliding mode control method to reach the stages of exercise, overcome the perturbation of the unknown parameters, the system is robust in the whole progress. Finally, Matlab Simulink toolbox in the design of the control system simulation, simulation results show that the designed controller not only to achieve precise attitude control and play a very part in inhibition to buffeting of attitude control of aircraft. At last, the thesis is summarized and the open problems for further research are also discussed. The controller is simple and easy to implement.