Adaptive second order sliding mode controller for vertical take-off and landing aircraft system

In this paper, an adaptive second order sliding mode (SOSM) controller is proposed for the vertical take-off and landing (VTOL) aircraft system. The VTOL aircraft is a highly complex nonlinear system suffering from the mismatched type of uncertainty caused by varying aerodynamic parameters and environmental disturbance. The proposed SOSM controller uses an adaptive tuning mechanism to deal with the mismatched perturbations. Chattering elimination in the control input is a remarkable benefit offered by the proposed adaptive SOSM controller. The control input does not contain any discontinuous signal as the sliding surface acts on the derivative of the control input. Simulation results confirm that the proposed adaptive second order sliding mode controller is superior in chattering mitigation as compared to the existing adaptive first order sliding mode controllers designed for the VTOL aircraft.