자율무인잠수정의 심도제어를 위한 비선형 적응제어기법

Abstract

This paper presents a direct method for adaptive nonlinear depth control of an autonomous underwater vehicle (AUV). As a matter of fact, by using a certain differential geometric theory, nonlinear diving behavior of an AUV could be transferred to a certain linear system, where many matured control methods could be applied. However, in this case, it is difficult for us to determine a reasonable coordinate transformation that should be a diffeomorphism. For this reason, in this paper, we solve the nonlinear diving equation of an AUV, which is not in a well-known strict-feedback form, directly using backstepping method. Furthermore, certain unknown-bound unstructured uncertainties are also considered in the vehicle's diving behavior. Proposed control scheme can guarantee all of the signals in the closed-loop system are uniformly ultimately bounded (UUB).