Adaptive robust sliding mode controller design for full control of quadrotor with external disturbances

This paper proposes two different adaptive robust sliding mode controllers for attitude, altitude and position control of a quadrotor. First it proposes a backstepping non-singular terminal sliding mode control with adaptive algorithm which applied to the quadrotor for free chattering, finite time convergences and robust aims. In this control scheme instead of regular control input, the derivative of the control input is achieved from non-singular terminal second-layer sliding surface. And an adaptive tuning method is utilized to deal with the external disturbances whose upper bounds are not required to be known in advance in the inner loop. Second nonlinear disturbance observer based on integral sliding mode with adaptive gains is proposed for position control which is known as outer loop. Stability and robustness of the proposed controller are proved by using the classical Lyapunov criterion. The simulation results demonstrate the validation of the proposed control scheme.