| Rotated wing aircraft is a unique new type of aircraft structure,whose rotor is non-torqued blade rotor and rotating with all or part of the wing which can avoid lift losing caused by down-wash flow in the helicopter mode,thus reduce the total weight of aircraft and increase the flight.Rotated wing aircraft which not only can cruise with highly speed like the aircraft but also can fly with vertical takeoff,vertical landing and hover on air like the helicopter.It has three flight modes: the helicopter mode,the transition mode and the airplane mode.Control is the key and difficult point in the transition mode because the angle of attack of rotated wing,the tail steering,the flight speed etc constitute a Time-Varying system.In this paper,the longitudinal control technology of rotated wing aircraft transition mode were studied.First of all,the aerodynamic models of rotated wing,fixed wing,rotors,flat tail of the rotated wing aircraft which are founded respectively,then combined with rotated wing aircraft longitudinal motion equation,the rotated wing aircraft longitudinal nonlinear simulation model is constructed in the simulink environment.It is helpful for the design of the rotated wing aircraft longitudinal control system.Then,the work of designing the shift channel based on trimming and analyzing the simulation model has finished.The model is linearized then it’s matrix A characteristic roots are analyzed for discussing the longitudinal stability of the model.The results show that the rotated wing aircraft transition section is stable under the fixed high constraint.Next,based on the linear model,the classical PID control theory is used to design rotated wing aircraft’s pitch attitude,altitude and speed control system,the feasibility of control scheme verified by the simulated results.The pole assignment method is used to design the control system of transition section.These simulated results show that the control system has good dynamic performance and anti-interference performance,satisfy the requirement of control indicators and keeping the height.Finally,to adopt new control scheme,the transition period of nonlinear model of control system has designed.The simulated results show that the designed control system satisfy the requirement of keeping the height and verify the feasibility ofcontrol scheme. |
