Research On Characteristics And Control Of FanWing

FanWing is recently developed to be a low-speed,large-load vehicle.With the help of a propulsive wing,it replaces the conventional fuselage with an extremely thick wing with partially embedded,distributed cross-flow fans for both thrust and flow control.Meanwhile,it could also offer short-field performance close to that of a helicopter,as well as operation economy close to that of a conventional aircraft.FanWing is becoming a research hotspot for its performances that between a conventional aircraft and a helicopter.As a new unmanned aircraft potentially serving both military and civilian markets,FanWing has a broad prospect.However,the domestic research on FanWing has just begun.Scientists mostly concentrate on the optimization of the fan-wing structure to improve the power system and the dynamic performance of FanWing,but rarely consider the control system.There is still a lot of work to do about the theoretical research and engineering applications.Therefore according to its aerodynamic characteristics and flight performance,the nonlinear model is established and the corresponding control systems are designed,including two PID control methods: the traditional elevator,aileron,and rudder control method,as well as the fan-wing control method,and the Uncertainty-and-Disturbance-Estimator(UDE)based control method.The research has important significance for the improvement of the flight performance and its development.Firstly,the nonlinear mathematical model during the course of taking off and cruising flight is built.And the characteristics of FanWing are analyzed.Therefore,both the similarities and differences between FanWing and the conventional aircraft are pointed out.Based on that,this thesis focuses on the results at different rotation speeds.The effects of the factors with and without control on the short take-off performances are discussed through numerial simulation.Thus,the allocation of the four factors is needed to gain a better take-off performance.All these researches will provide guidelines for the structural design and the flight control of FanWing.Secondly,inspired by the successful application of the thrust vectoring technique in flight control,a technique that we called ‘fan wing control system' is proposed.To start from the control system design in the air,this thesis introduces the traditional aerodynamic surfaces control and fan wing control both in longitudinal control and lateral control.And the longitudinal control system is one of the emphases for research.The comparative analyses show the feasibility of the fan wing control system instead of the aerodynamic surfaces control.Further more,the influences of the additional nose down moment enlargement on the fan wing longitudinal control are studied.Thirdly,according to the high pitch angle flight of FanWing,the longitudinal take-off and landing control systems are presented.And the combination of the elevator control and the fan wing control is proposed to solve the coupling between the height control and the attitude control.At the same time,this thesis proposes a control solution based on pitch rate to realize the stability control of the pitch attitude.On this basis,the UDE based control method is applied to the longitudinal control of FanWing.A bandwidth parameterized robust attitude control scheme with a simple parameter tuning algorithm is presented.And the final simulation proves that the UDE control method has more superior longitudinal attitude control performances than the combination control by the simulation and the performance analysis.At last,based on the MATLAB simulation environment,the nonlinear simulation of FanWing is realized.The simulation results of different modes show the feasibility and the autonomous tracking capability of the two control systems,and the stability control of the fan wing control system is feasible when the aerodynamic surface is out of order.