Depth Control of an Autonomous Underwater Vehicle with System Uncertainties Based on Discrete Variable Structure System

J. Ocean Eng. Technol. 1997;11(4):169-179.

이산 가변구조제어기를 이용한 자율무인잠수정의 심도제어

이판묵,홍석원,전봉환

한국기계연구원 선박해양공학연구센터,한국기계연구원 선박해양공학연구센터,한국기계연구원 선박해양공학연구센터

Keywords: Discrete Control, VSS, Quasi-Sliding Mode, Parameter Uncertainty, AUV

핵심용어: 이산제어, 가변구조시스템, 의사-슬라이딩 모드, 불확실성, 자율무인잠수정

Abstract

This paper presents a discrete-time sliding mode control of an autonomous underwater vehicle with parameter uncertainties and long sample interval based on discrete variable structure system. Although conventional sliding mode montrol techniques are robust to system uncertainties, in the case of the system with long sample interval, the sliding control system reveals chattering phenomenon and even makes the system unstable. This paper considers the AUV which acquires position informations from a surface ship through an acoustic telemetry system with a certain discrete interval. The control system is designed on the basis of a Lyapunov function and a sufficient condition of the switching gain to make the system stable is give. Each component of the switching gain can be determined separately one another. The controller is robust to the uncertainties, and reaching condition of the control system is satisfied for any initial condition. This control law is a generalized form of the discrete sliding mode control and reduce the chattering problem considerably. Motion control of the AUV in the vertical plane shows the effectiveness of the proposed technique.