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Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

Adaptive Fuzzy Control Design Based on Nonlinear System of Underwater Vehicle
Xingbang Pan, Guohua Xu, Zhemin Huang, Sha Xie

Underwater Technology Laboratory, School of Naval Architecture and ocean Engineering, Huazhong University of Science and Technology
Wuhan, Hubei Province, China

ABSTRACTAUV HYDRODYNAMIC MODEL

The control effect of traditional PD controller is poor, because AUVhydrodynamic model is a typical nonlinear system. This paper uses
fuzzy control theory to design fuzzy controller. Based on AUV
nonlinear hydrodynamic model, four controllers are designed: PDcontroller, Mamdani fuzzy controller, T-S fuzzy controller and adaptive
fuzzy controller. Based on SIMLINK simulation, a good heading angle
control curve is obtained by repeatedly adjusting the parameters. The
experimental results show that the designed fuzzy controller has
reliable control

Establish coordinate system(1) Geodetic coordinate system E -X1Y1Z1: its origin e is any point onthe earth, and the three axes are X1, Y1, Z1 respectively. The Z1 axis isdetermined by the right-hand screw rule, and the Z1 axis generally
points to the geocenter. Although the earth has a certain rotation speed,
this speed is very small and has little impact on low-speed objects.
Generally, the earth coordinate system is regarded as an inertial
coordinate system, so Newton's kinematics law can be applied.

KEY WORDS: AUV, underwater vehicle, nonlinear system,(2) Body coordinate system O-XBYBZB: this coordinate system isfixedly connected with the submarine. The origin O is usually locatedat the floating center of the AUV, the XB axis is usually along the axis
direction of the submarine, YB is generally pointing to the starboard
side along the transverse motion direction, and the ZB axis is pointing
to the vertical axis direction of the AUV. The body coordinate systemmeets the right-hand spiral law. As shown in Fig. 1.

Adaptive fuzzy control

INTRODUCTION
With the development of science and technology, there are more andmore kinds of controlled objects, and the control model is more andmore complex. At the same time, higher requirements are put forward
for the accuracy of control, so the linear model is not applicable.
Submarine hydrodynamic model is a typical nonlinear system, and thetraditional linear control method is no longer applicable.
In the past few decades, many emerging control theories produced by
the research on nonlinear systems have generally combined Lyapunovstability theory, such as the Backstepping control theory represented by
Kokotovic and the micro geometric control theory represented byProfessor Isidori of Italy, the dynamic surface control design method
developed based on backstepping control theory is represented bySwaroop and Hedrick. E.H.Mamdani (1974) first used fuzzy logic in
the control of the boiler, marking the birth of fuzzy control.

Fig. 1 Geodetic coordinate system and carrier coordinate system

Fuzzy control theory is based on fuzzy set theory, fuzzy language andfuzzy logic. It is the application of fuzzy mathematics in control system
and a kind of nonlinear intelligent control.

(3) Pose and velocity definition. The underwater motion of the vehicle
has six degrees of freedom, so six degrees of freedom parameters areneeded to describe its motion characteristics.

In this paper, the fuzzy control theory represented by Zade andMamdani is adopted. For the hydrodynamic model of AUV, PDcontroller and three fuzzy controllers are designed: Mamdani PDcontroller, T-S PD controller and adaptive fuzzy controller. Based onSIMLINK platform simulation, the heading angle control curve isobtained.

η1 = [ xz]Tη2 = [φ θ ψ ]v1 = [u v w]

v2 = [ p q r ]yTT

τ1 = [ X Y1175TZ]

Tτ2 = [KM(1)N]T