Research On Fault Tolerant Control Strategy For Six-Rotor Aircraft Power System

The multi-rotor helicopter,depending on its advantages of small size,light weight and low requirements of landing places has been used rapidly and widely in military and civil fields since its birth.The six rotor aircraft,as the representative of the multi rotor aircraft,is relatively simple in structure,stronger in load capacity than in the general four rotor,and has the features that are easy to operate as the four rotor.With the application of six-rotor aircroft being used more and more widely in various fields,various of crashes happens continually,for example,due to aging of drive components and collisions between rotor blades and obstacles during flight,etc.Therefore,higher requirements on their reliability and safety have been put forward,which has stimulated domestic and foreign scholars' interest in studying the fault-tolerant control strategies.The six-rotor aircroft is taken as the research object in this article to discuss the method when the typical malfunction of the power system occurs.The specific research works are as follows:First of all,the research status of controling strategy for six-rotor aircroft is deeply analyzed,and common fault types are summarized.The body structure and flight working principle of six-rotor aircroft are described.Combining the Newton-Euler law,the analysis of attitude transformation relationship and the force of the aircroft,the attitude equations and position coupling equations of six-rotor aircroft have been established,and make them become predigestion.Secondly,based on the mathematical model,the reference model with good performance is designed by using the Linear Quadratic Regulator(LQR)method to deal with the problem of controlling complexity and strong state coupling of a six-rotor aircroft.At the same time,considering the advantages of sliding mode variable structure control method and the characteristics of integral function which can effectively eliminate the steady-state error,the integral sliding surface is designed based on the pseudo-inverse theory and the state error.Then,aiming at the problem that the traditional PID control method has poor robustness to external disturbances,a model reference sliding mode attitude controller in the presence of interference is designed.By decoupling the attitude angles,the sliding mode position controller is designed,and the stability of the closed-loop system is analyzed by using Lyapunov stability theory.Again,based on the design of basic attitude and position controllers,a control distribution strategy idea is introduced to the typical common faults in rotor motor of the six-rotor aircroft power system.The sliding mode observer is used to estimate the fault information matrix which can adjust the control distribution matrix online,thus reducing the use of fault actuators and realizing the purpose of fault-tolerant control.Then,the typical failure phenomena are selected to carry out the simulation experiment analysis.Finally,the work of the full text is summarized,and the existing problems and subsequent research directions are briefly arranged.