Phase modulation of robust variable structure control for nonlinear aircraft

This paper concerns phase plane description and modulation of the performance for a nonlinear Unmanned Aerial Vehicle (UAV) system based on Variable Structure Control (VSC) by reaching sliding mode. The novelty lies in the application of a phase analysis approach to achieve a robust controller for a complex nonlinear system. The aircraft dynamics are introduced and approximately linearized and decoupled on-line using feedback linearization theory. Then the sliding mode control (SMC) scheme is accomplished for the decoupled sub-channels. The phase modulation method is applied for theoretically ensuring further robustness. The simulation results demonstrate the efficiency and effectiveness of the proposed strategy.