Nonlinear stabilization control of tilt rotor UAV during transition flight based on HOSVD

Aiming at the transition progress of tilt rotor UAV and considering the characteristic that tilt angle leads the mode transition, a new control approach is proposed. Jacobian linearization is used at an appropriate quantity of equilibrium points chosen at equal interval in the range of tilt angle, then putting the resulting LTI systems into a tensor and discarding smaller and zero singular values together with their corresponding singular vectors through higher older singular value decomposition (HOSVD), reconstructing the reduced-rank tensor to obtain a polynomial system constructed by a finite number of vertexes and their weight functions. Based on SOS programming technique and Lyapunov stability theory, both the stability analysis and controller design problems are converted into solving a parameter-dependent linear matrix inequalities (LMI), which can be solved directly through SOS technique. Finally, the transition progress of the fixed wing mode to helicopter mode is simulated in the longitudinal channel, the result shows that the aircraft can complete the conversion mode flight accurately along the predetermined trajectory and the controller is robust to the variations of the aerodynamic parameters and external disturbance.