Quaternion-based position control of a quadrotor unmanned aerial vehicle using robust nonlinear third-order sliding mode control with disturbance cancellation

Abstract

In this paper, we propose a robust nonlinear position and attitude control method for quadrotor using higher order sliding mode control concept. The control of quadrotor is realized in an inner- and outer-loop structure. Both inner- (attitude control) and outer (position control)-loop controllers are synthesized using third-order sliding mode control. The attitude control is designed in a quaternion framework to avoid gimbal lock and for better computational efficiency. A low-pass filter is used to reduce the effect of chattering in higher order sliding mode. A disturbance observer is designed for disturbance estimation. The robustness of proposed control method is ensured by providing the disturbance compensation term in the control law. Lyapunov stability analysis is provided for both inner- and outer-loop controls. Numerical results show that the proposed method provides effective control solution under continuous disturbance/uncertainties due to unmodeled dynamics, parameter variations, and external disturbance with high position accuracy.