Experimental Validation of a Model-Free High-Order Sliding Mode Controller with Finite-Time Convergence for Trajectory Tracking of Autonomous Underwater Vehicles

Josué González-García,Alfonso Gómez-Espinosa,Luis Govinda García-Valdovinos,Jesús Arturo Escobedo Cabello,Tomás Salgado-Jiménez,Enrique Cuan-Urquizo

doi:10.3390/s22020488

Abstract

Several control strategies have been proposed for the trajectory tracking problem of Autonomous Underwater Vehicles (AUV). Most of them are model-based, hence, detailed knowledge of the parameters of the robot is needed. Few works consider a finite-time convergence in their controllers, which offers strong robustness and fast convergence compared with asymptotic or exponential solutions. Those finite-time controllers do not permit the users to predefine the convergence time, which can be useful for a more efficient use of the robot’s energy. This paper presents the experimental validation of a model-free high-order Sliding Mode Controller (SMC) with finite-time convergence in a predefined time. The convergence time is introduced by the simple change of a time-base parameter. The aim is to validate the controller so it can be implemented for cooperative missions where the communication is limited or null. Results showed that the proposed controller can drive the robot to the desired depth and heading trajectories in the predefined time for all the cases, reducing the error by up to 75% and 41% when compared with a PID and the same SMC with asymptotic convergence. The energy consumption was reduced 35% and 50% when compared with those same controllers.

Highlights

Published: 9 January 2022Autonomous Underwater Vehicles (AUV) have permitted us to deepen the knowledge of the oceans and seafloors
Autonomous navigation can be performed by different methods such as waypoint tracking, path following, and trajectory tracking [8]
General equations for kinematics and hydrodynamics of the AUVs are introduced along with the particularities of the robot used in the experiments

Summary

Introduction

Autonomous Underwater Vehicles (AUV) have permitted us to deepen the knowledge of the oceans and seafloors. The use of AUVs in tasks such as structural inspection [1,2], environmental risks detection [3], and mapping underwater structures [4], among others, increases the safety of the mission and the reliability of their results [5], and reduces the operational costs considerably [6]. Autonomous navigation can be performed by different methods such as waypoint tracking, path following, and trajectory tracking [8]. In the waypoint tracking method, the vehicle navigates throughout a set of pre-defined waypoints. This is the easier method to be implemented, it could result in some uncertainty in the trajectory followed by the vehicle between two waypoints [9]. The integration of time and space restrictions makes trajectory tracking the most complex of Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations

Methods

Results

Conclusion