Active Fault-tolerant Control Method Research On Missile Flight With The Constraint Of Actuator

In modern warfare,as the complexity of missile control system increases,the possibility that cause system fault also increased.The fault of control system not only affect the accuracy and stability of flight,even may cause huge damage in the battlefield.The flight time of missile is often short,which is difficult to design fault detection and diagnosis and fault tolerant control model.Consequently,this dissertation tries to carry out study on modeling of disturbance system,fault observation and diagnosis,autopilot parameters design online and analysis and control allocation optimization with the actuator fault.First,aiming at the feature of missile,some coordinate are established,The motion equation in longitudinal plane of missile is established by analyzing the forces and torque on missile,in the assumption of small perturbation and coefficient freezing method,disturbance equation and transfer function of missile are derived and modeling the dynamic model of missile with the fault,which lays the foundation for the subsequent work in this dissertation.Second,aiming at the rudder fault of missile,considering that reduced-order observer is sensitive to noise,observer based on model reference adaptive control is used to observe the fault parameters.The simulation results indicate that observer can track the parameter accurately and convergent rapidly with the noise,which verifying the rapidity and robustness of this method.On this basis,simple linear regression analysis is used to do the logic diagnosis to get the type and parameter of fault.Third,considering the impact on control system caused by rudder fault,present section analyzes the impact of rudder fault on handle torque,dynamic coefficients and transfer function of missile body.Aiming at the rudder fault,a active fault tolerant control algorithm of controller parameter design is proposed,performance index is designed according to the fault degree,the simulation results indicate its effectiveness.Finally,considering that direct allocation method can't adapt to the consequence with rudder fault,bases sequence control method is used to optimize the allocation process of control instruction.Aiming at the jump of allocation result,some improvement is done on bases sequence control method.Comparing the simulation results between direct allocation method and bases sequence control method,bases sequence control method performs better than direct allocation method,which show the correctness and applicability of the method.