Robust level flight control design for scaled Yak-54 unmanned aerial vehicle using single sliding surface.

This paper deals with devising robust nonlinear control strategy for benchmark system of scaled Yak-54 Unmanned Aerial Vehicle. Authors considered the applications of sliding mode controllers to the longitudinal flight dynamics of the Yak-54 UAV for executing maneuvers over full flight envelope. Unlike the classical technique of the two sliding surfaces for the two loops a single surface is selected for the level flight. Control of unmanned aerial vehicle involves the problem of incomplete measurements, modeling uncertainties and external disturbances which makes flight dynamic analysis and control system design difficult. We present an innovative robust control strategy based on powerful tools provided by the theory of sliding mode control algorithms. First order sliding mode controller are designed but they provide chattering at the control input thus a non linear second order super twisting controller is used to provide chattering free control with improved robust stabilization.