Research On Fault Diagnosis Methods For Four-rotor Aircraft

With the characteristics of simple structure,flexible operation,small size,light weight,strong load capacity,four-motor aircraft has important applications in military and civilian fields.Because the four-rotor is a nonlinear,multivariable and strong coupling dynamics system,so it is prone to failure.In order to improve the safety and reliability of four-rotor aircraft,fault diagnosis has become a hot issue.In this paper,the actuators' fault diagnosis methods of four-rotor aircraft are researched.The main work is as follows:The research statuses at home and abroad on the four-rotor aircraft fault diagnosis are summarized.By analyzing the composition and structural characteristics of the four-rotor,the dynamic model and fault model are established.Besides,the Qball-X4 experimental platform and composition are presented.Aiming the actuators' failure problems of four-rotor aircraft,the fault diagnosis methods based on the model are studied.Fault diagnosis method of Qball-X4 based on particle filter,fault diagnosis method of Qball-X4 based on cost reference particle filter residual likelihood ratio test and fault diagnosis method of Qball-X4 based on unknown input observers are proposed.Building fault diagnosis model in Qball-X4 experimental platform,communicating by wireless LAN,locating by 24 Optitrack positioning camera and downloading code to the processor,system is controlled in real time.By injecting faults during flight,fault is diagnosed according to residual signal outputs from the three algorithms respectively.Fault diagnosis result shows,residuals remain near zero under normal circumstances,and residuals transition when it failure.Therefore,comparing the residuals to the set thresholds determines whether the failure happens.Analyzing and comparing the proposed three methods and giving the prospect of future work.