Research On Attitude Control Considering The Static Instability Of Missile

In the past,researchers designed missiles to simplify their attitude control systems,it was usually expected that the center of mass was always in front of the focus during the flight of the missile,and the static stability of the missile was always negative,that is to say,the missile was statically stable under various circumstances.In order to improve the mobility,the missile flight speed,endurance capability,reduce the structure weight of the missile,the design concept of relaxing static stability has been gradually applied to the design of missile attitude control system,and various kinds of statically unstable missile have come out one after another.In attitude control design of static-unstable missile,it is difficult to obtain accurate mathematical model due to the influence of uncertain missile parameters,unmodeled dynamic state of missile and external interference.Therefore,the traditional PID controller is sometimes difficult to achieve the required performance index.Aiming at this problem,the adaptive control theory is introduced into the attitude control system design of statically unstable missile.This paper takes statically unstable missile as the research object,designs three attitude controllers by using PID control method and model reference adaptive control method,and conducts simulation analysis and comparison.The main contents are as follows:1.The present situation of statically unstable missile research,the composition of missile attitude system and the application of modern control theory in missile attitude control system are analyzed,the missile mathematical model and transfer function are deduced,and the mathematical model of attitude control system is determined.2.The concept and judgment method of missile longitudinal static stability are summarized.The stability of statically unstable missile is analyzed and the PID controller design of statically unstable missile is completed.3.The basic principle of adaptive control and the design method of model reference adaptive system are introduced.According to Lyapunov theory and super stability theory,the adaptive law is deduced and two attitude adaptive controllers for statically unstable missiles are designed.The application of PID control and model reference adaptive control in static-unstable missile is emphatically studied.The performance indexes of the three attitude controllers designed are compared and analyzed,and finally the attitude controller of static-unstable missile with better performance is obtained.