Estimation of Hydrodynamic Coefficients for an AUV Using Nonlinear Observers |
Kim, Joon-Young; |
College of Ocean Sciences, Cheju National University; |
비선형 관측기를 이용한 무인잠수정의 유체동역학 계수 추정 |
김준영; |
제주대학교 해양과학대학; |
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© 2006 The Korean Society of Ocean Engineers
Open access / Under a Creative Commons License
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Keywords:
Autonomous underwater vehicle (AUV), Hydrodynamic coefficient, Nonlinear observer, Extended ka1man filter, Sliding mode observer, Sliding mode control |
핵심용어:
무인잠수정, 유체동역학 계수, 비선형 관측기, 비선형 칼만 필터, 슬라이딩 모드 관측기, 슬라이딩 모드 제어 |
Abstract |
Hydrodynamic coefficients strongly affect the dynamic performance of an AUV. Thus, it is important to know the true values of these coefficients, in order to accurately simulate the AUV's dynamic performance. Although these coefficients are generally obtained experimentally, such as through the PMM test, the measured values are not completely reliable because of experimental difficulties and errors. Another approach, by which these coefficients can be obtained, is the observer method, in which a model-based estimation algorithm estimates the coefficients. In this paper, the hydrodynamic coefficients are estimated using two nonlinear observers: a sliding mode observer and an extended Kalman filter. Their performances are evaluated in Matlab simulations, by comparing the estimated coefficients obtained from the two observer methods, with the experimental values as determined from the PMM test. A sliding mode controller is constructed for the diving and steering maneuver by using the estimated coefficients. It is demonstrated that the controller, applied with the estimated values, maintains the desired depth and path with sufficient accuracy. |
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