Research on Transition Flight Control Method of QTR Aircraft

Abstract

AbstractDue to the non-affine and non-linear characteristics of quad tilt rotor (QTR) aircraft in transition process, two kinds of methods were used to design the flight control law of transition process in this paper, nonlinear dynamic inverse method based on equivalent control input and the incremental nonlinear dynamic inverse method based on incremental affine nonlinear system, the theoretical analysis and simulation verification of these two methods were carried out simultaneously. The first approach converts the original non-affine system to an affine system by introducing equivalent control inputs, while the second method converts the original non-affine system into an affine system by first-order Taylor expansion, the control input of new affine system is the increment of original system control input. The simulation results indicate that the three transition control laws can ensure QTR aircraft transit between helicopter mode and fixed-wing mode steadily when satisfying certain flying quality, moreover, the two methods have strong suppression effect on parameter perturbation in certain range. The control commands of the first method have jump phenomenon during flight mode switching, while the second method keeps control commands continuous during flight mode switching due to the incremental output of control law.KeywordsNon-affine systemEquivalent control inputIncremental affine systemParameter perturbationFlight mode switching