Research On Conversion Mode Of Tiltrotor Aircraft By Simulation

Tiltrotor aircraft are hybrid aircraft that attempt to combine the hover and vertical take-off and landing capability of a helicopter with the speed and range of a fix-wing airplane. It is meaningful to study the conversion process of helicopter mode and airplane mode.This thesis contains two parts: the first, as a prototype of tiltrotor aircraft, the dynamic model of XV-15 was analyzed. Then its flight modes were analyzed, and also conversion corridor was analyzed; the second, based on the research method of first part, model tilt rotor aircraft was theory modeled, and by use of MATLAB, its simulation model was built.Based on the complex aerodynamic of XV-15 tiltrotor aircraft, the mathematical model of the tiltrotor was established with the consideration of the influence of the rotor wake on the airframe aerodynamics, such as wing, horizontal tail and vertical tail. Then simulation model was built in MATLAB, and was analyzed by trim operation. The linear model was then made nearby equilibrium point by linmod operation. After trimmed, the two flight modes were analyzed: helicopter mode and airplane mode. They were analyzed in four ways: the stability and control derivatives themselves, the roots of the plant (A) matrix, frequency response or Bode plots and time response to various inputs. Based on the results of simulation, operating characteristics of XV-15 tiltrotor aircraft were qualitative analyzed, and when to fade out the rotor control was determined, and also the conversion corridor was determined. Inside the conversion corridor, a conversion route that had the least trimmed pitch attitude was suggested.Besides, based on the similar method that used in XV-15 modeling, theory model of model tiltrotor aircraft was built, and then simulation model was built in MATLAB. At last, the next research direction and research method were raised...