Adaptive Cooperative Diving of Saucer-Type Underwater Gliders Subject to Model Uncertainties and Input Constraints

This paper is concerned with the cooperative diving problem of homogenous under-actuated saucer-type autonomous underwater gliders subject to model uncertainties, input constraints as well as external disturbances. A modular back-stepping design method is used to design a robust adaptive cooperative diving controller for each glider. Especially, a kinematic control law is at first designed by employing a line-of-sight guidance principle, and a path variable update law is developed based on a synchronization strategy. Next, in order to identify the unknown dynamics of gliders, an estimation model is constructed by using a fuzzy approximation technique and a low-frequency learning scheme. Finally, it is proved that the closed-loop system is input-to-state stable by using a cascade stability analysis. The simulation results are given to demonstrate the effectiveness of the proposed method for cooperative diving of autonomous underwater gliders in a vertical plane.