Fixed-time sliding mode formation control of AUVs based on a disturbance observer

Abstract

In this paper, we investigate formation tracking control of autonomous underwater vehicles &#x0028 AUVs &#x0029 with model parameter uncertainties and external disturbances. The external disturbances due to the wind, waves, and ocean currents are combined with the model parameter uncertainties as a compound disturbance. Then a disturbance observer &#x0028 DO &#x0029 is introduced to estimate the compound disturbance, which can be achieved within a finite time independent of the initial estimation error. Based on a DO, a novel fixed-time sliding control scheme is developed, by which the follower vehicle can track the leader vehicle with all the states globally stabilized within a given settling time. The effectiveness and performance of the method are demonstrated by numerical simulations.