Disturbance Observer Based Sliding Mode Control for Lateral Motion of an AUV

A lateral motion control problem of an experimental autonomous underwater vehicle (AUV) MAYA AUV is considered. In this paper, a disturbance observer based sliding mode control (DOB-SMC) scheme is proposed in the presence of parameter perturbation and disturbances. During motion, a highly uncertain ocean environment demands robust control to handle the parameter perturbations and disturbances. This problem can be directly resolved by a sliding mode control (SMC) design. The disturbance observer (DOB) is designed to approximate the equivalent control of SMC containing disturbances. To restrain the chattering, DOB is designed such that the disturbance estimation converges to disturbance exponentially and feedback switching gain converges to zero exponentially. The proposed control scheme is examined through a computational tool.