Research On Nonlinear Control Method Of Electro-hydraulic Driving Pitch Mechanism

The control performance of the electro-hydraulic driving pitching mechanism in the missile launching device is the key factor determining the tracking accuracy and intercepting capability of the air defense weapon.Therefore,it is necessary to study its advanced control method to reduce the pitching time of the launching frame and improve the tracking accuracy.The nonlinear characteristics and model uncertainty of the electro-hydraulic driving pitching mechanism are the main obstacles to the development of high-precision servo performance.Therefore,it is of great significance to study the high-performance nonlinear control method to solve the problems caused by system nonlinearity and model uncertainty,and then improve the control performance of the electro-hydraulic driving pitching mechanism.In this dissertation,the key control problems of electro-hydraulic driving pitching mechanism are carried out in the following aspects:(1)The basic composition and working principle of the electro-hydraulic driving pitching mechanism are introduced,and the main parameters of the system are designed according to the technical requirements.Based on the analysis of the nonlinear characteristics of the system,a nonlinear mathematical model of the electro-hydraulic driving pitching mechanism is established.This model lays a foundation for the subsequent high performance nonlinear controller design.(2)By considering the parameter uncertainty and bounded uncertainty nonlinearity of electro-hydraulic driving pitching mechanism,an integral robust control strategy is designed,which can guarantee semi-global asymptotic stability of system.At the same time,in order to avoid the randomness and potential high gain feedback caused by artificially adjusting the robust gain ?,the idea of integral robust control method and adaptive control are combined to design an adaptive integral robust controller.The adaptation law assists the ? value to make online self-adjustment according to the actual working conditions.(3)In order to overcome the nonlinear characteristics of electro-hydraulic driving pitching mechanism and the influence of unmodeled dynamics on system performance in model uncertainty,based on the nonlinear model of electro-hydraulic driving pitching mechanism,an adaptive robust controller considering unmodeled friction dynamics and an adaptive robust controller considering unmodeled flexible dynamics are proposed to actively compensate friction dynamics and flexible dynamics,respectively.It proves that these two control strategies are able to guarantee the uniformly bounded stability of the system.(4)The adaptive integral robust control method and the robust adaptive control method considering flexible dynamics are experimentally verified by the hydraulic cylinder position servo experimental platform.The excellences of the proposed control methods are verified by comparison with traditional control methods and analysis of experimental results.