Backstepping based integral sliding mode control for autonomous underwater vehicles

A backstepping-based integral sliding mode control is proposed for vertical plane control of autonomous underwater vehicles. The adaptive backstepping control law is derived for the nominal system to deal with unmatched uncertainty, while the integral sliding mode control is introduced in order to compensate for the matched perturbations. Therefore, the unmatched uncertainty is greatly reduced and the matched perturbations are cancelled. The dynamics of closed-loop system tend to the nominal system under the backstepping control. Simulations support the general analysis and show the effectiveness of this combination.