Fuzzy Depth Control of Small Cylindrical Object Navigating near Free-Surface

Abstract

Small cylindrical object navigating near free-surface is subject to wave disturbance. Wave disturbance can dramatically influence the depth control of the near-surface navigating object. A self-regulating fuzzy depth control method is proposed to keep the small cylindrical object navigate at the expected depth under free-surface disturbance. The near-surface dynamic model of the cylindrical object is presented and the fuzzy depth control method is modeled. The results obtained by a series of hardware-in-loop simulations demonstrate that the self-tuning fuzzy depth control method is valid to keep the small cylindrical object navigate steadily in the expected depth under free-surface disturbances.

Hydrodynamic Behavior of a Submerged Spheroid in Close Proximity to the Sea Surface

“…The vector is expressed in the co-ordinate system (r, θ, z). Finally, a radiation condition, specifying that propagating disturbances must exhibit outward behavior should be fulfilled (see Equation (13) in Ref. [45]).…”

“…Similar physical arguments were employed by [12] to elucidate the negative added mass and sharp force coefficient peaks and hydrodynamic characteristics of groups of interacting axisymmetric submerged bodies near the free surface or seabed. In addition, Shao et al [13] developed a self-regulating fuzzy depth control method to maintain a cylindrical submerged structure at a specific depth below the free water surface under free surface disturbances. Also, the hydrodynamic coefficients of twin connected circular cylinders were studied in [14].…”

Depth Controller Design for Submerged Body Moving near Free Surface Based on Adaptive Control

“…Linear quadratic regulator (LQR), Fuzzy 등을 이용한 제어기 설 계가 주를 이루었다 (Richards and Stoten, 1982;Hao et al, 2004;Choi et al, 2006;Choi et al, 2008;Kim et al, 2009;Shao et al, 2012). Hao et al(2004) …”

Hydrodynamics of an underwater vehicle near the sea surface

“…Similar physical argumentation was applied by Mavrakos (1993) in order to explain the negative added mass and sharp peaks of the force coefficients and the hydrodynamic characteristics of groups of interacting axisymmetric submerged bodies near the free surface or the seabed. Recently, a self-regulating fuzzy depth control method was developed by Shao et al (2012) in order to maintain a cylindrical submerged structure at a specific depth below the free water surface, under free surface disturbances.…”