An analysis of the stability and chattering reduction of high-order sliding mode tracking control for a hypersonic vehicle

This paper addresses the stability and chattering reduction issue of the high-order sliding mode tracking control for a hypersonic vehicle. Quasi-continuous third order mode (Q3OSM) and fourth order sliding mode (Q4OSM) controllers are proposed for the tracking control of velocity and altitude of the aircraft, respectively. To alleviate the chattering phenomena, a method incorporating the idea of artificial increase of the relative degree in quasi-continuous high-order sliding mode (QHOSM) is introduced. In the meanwhile, the transient time function is constructed using the initial values of the output and their derivatives through the homogeneous technique. Comparison of the results by QHOSM control with those by classical sliding mode control (SMC) is presented. It is shown that QHOSM controller delivers a high dynamic tracking performance and can reduce chattering phenomena significantly. It is also shown that the resulting controller has strong robustness to parameter uncertainties. Simulation results demonstrate the effectiveness of the controller design methodology.