Nonlinear Reduced-Order Observer-Based Predictive Control for Diving of an Autonomous Underwater Vehicle

Xuliang Yao,Yu Peng,Guangyi Yang

doi:10.1155/2017/4394571

Abstract

The attitude control and depth tracking issue of autonomous underwater vehicle (AUV) are addressed in this paper. By introducing a nonsingular coordinate transformation, a novel nonlinear reduced-order observer (NROO) is presented to achieve an accurate estimation of AUV’s state variables. A discrete-time model predictive control with nonlinear model online linearization (MPC-NMOL) is applied to enhance the attitude control and depth tracking performance of AUV considering the wave disturbance near surface. In AUV longitudinal control simulation, the comparisons have been presented between NROO and full-order observer (FOO) and also between MPC-NMOL and traditional NMPC. Simulation results show the effectiveness of the proposed method.

Highlights

Autonomous underwater vehicle (AUV) is an important tool for ocean exploitation
When AUV navigates near surface, diving control is one of the key research fields; a variety of methods have been proposed for AUV in vertical plane
This paper proposed MPC-NMOL design method based on nonlinear reduced-order observer (NROO) for a nonlinear Lipschitz model of AUV

Summary

Introduction

Autonomous underwater vehicle (AUV) is an important tool for ocean exploitation. Due to its strong autonomous ability, AUV can complete the mission given by human and has become widely used in military and scientific research [1]. In [13], a sampling based MPC is proposed to generate the control sequence with constraints effectively These methods have a good performance in the field of MPC use for AUV, but they do not deal with wave disturbances. Zhang et al [17] considered the elevator angle constraints and proposed a controller based on MPC with artificial bee colony algorithm, and a classical linear state observer is used. Kinsey et al [20] proposed a nonlinear observer based on dynamic model of AUV, which is used to estimate the vehicle’s velocity In their model, the coupling terms are neglected and there was only one degree of freedom. The nonlinear reduced-order observer is designed according to the dynamics above, to estimate the unmeasured state variables of AUV.

AUV Vertical Plane Dynamics

Nonlinear Reduced-Order Observer Design

Model Predictive Control with Nonlinear Model Online Linearization

Conclusions