Integrated vector field and backstepping control for quadcopters

In this work, we present an Integrated Guidance and Controller (IGC) scheme to drive quadcopters in path-following tasks with obstacle avoidance and constant uncertainty rejection. This scheme is based on the combination of a time-varying artificial vector field and Backstepping with integral action control. The vector field switches between two behaviors: (i) path-following; and (ii) obstacle circumnavigation to allow collision avoidance. This vector field is then integrated into a nonlinear controller designed via Backstepping with Integral Action to deal with the quadcopter vehicle dynamics and reject constant uncertainties. The considered vehicle model is based on quaternion algebra. The control inputs are considered to be the total thrust and torques. Stability is proved by using Lyapunov's Theory and Matrosov's Theorem.