Water velocity sensor with the ability to estimate the sideslip angle based on Bernoulli's law for use in autonomous underwater vehicles

Abstract

One of the most important parameters in navigating an Autonomous Underwater Vehicle (AUV) is velocity estimation. There are a variety of water velocity sensors that can measure the velocity of an AUV using different technologies. For example ultrasonic, electromagnetic, optical, paddlewheel and Doppler velocity sensors are used for measuring the water velocity. In this paper, the aim is to design and manufacturing an inexpensive water velocity sensor based on differential pressure that can measure the surge and sway velocity of an AUV using Bernoulli's law. In the present paper, in order to prove the claim of the proposed theory, the results of Computational Fluid Dynamics (CFD) related to a part of the body of an AUV are also presented. To evaluate the performance of the proposed sensor, a part of the body of an AUV was constructed and tested in the towing tank of the National Iranian Marine Laboratory (NIMALA). In order to check the accuracy of the proposed sensor, a velocity sensor is used as a reference sensor that is installed on the towing tank. Finally, the results show that in the speed range of 0.5–4.5 m/s, the accuracy of measuring the axial velocity is about 0.05 m/s (1% Full scale span (FSS)), and for speeds higher than 2 m/s, the accuracy of estimating the sideslip angle and sway velocity are respectively 0.2° and 0.015 m/s.