Closed-Loop AUV Temperature Control Using Internet of Underwater Things-Based Multi-Node Underwater Communication

As the Internet of Things has become an integral part of the modern digitized society, connecting devices in real-time and exchanging data, its limitation to land needs to be overcome. To reduce the human effort in underwater applications, AUVs have played a significant role in underwater surveillance, oceanography, marine defence systems and environment monitoring. A significant challenge exists in underwater communication due to the limited range and harsh underwater environment that can cause attenuation and distortion. As the temperature in deep waters varies, the AUVs need to balance the inside temperature at an ambient condition for its batteries and electronics to perform at maximum efficiency. A temperature-dependent closed loop system is implemented for remote access and AUV protection, which uses an underwater radio frequency-based communication system along with the Internet of Things to transmit data from water to land for monitoring purposes. The battery temperature and other parameter data are transmitted from the AUV to the land through radio communication using the multi-node system for faster communication over a longer range. The data is then uploaded to the cloud using the internet. With the help of IoT, the control centre can access AUV data remotely and control the temperature in the AUV for the efficient performance of the battery. The overall system has been demonstrated using embedded system sensors and actuators and RF transmitters with Arduino and ESP32.

I. Introduction

The last decade has observed growth in technologies in underwater applications. There has been a significant shift from manned underwater vehicles (MUVs) and remotely operated vehicles (ROVs) to autonomous underwater vehicles (AUVs) for applications such as oceanography, environment monitoring, underworld industry and underwater surveillance in the defence sector. AUVs have proven to provide higher efficiency at a lower cost with a larger area of reach. As they are self-propelled, AUVs follow a specific course collect data on the way and later transmit the data to the remote-control centre wirelessly. These unmanned vehicles are specifically designed for deep sea diving to reach areas where humans and larger vehicles can't access such as deep trenches or ice shelves and even at a greater depth. Day-by-day the increasing demand for lithium-ion batteries has not been limited to terrestrial applications in electric vehicles but also gave rise to the need for its use in underwater vehicles. The longer life cycle, lower self-discharge rates and higher charge density of lithium-ion batteries make them suitable for adoption in underwater vehicles. However, temperature is an important criterion as lithium-ion batteries are directly affected by the change in temperature and the underwater environment has a varied temperature curve. A well-maintained temperature within the batteries will help operate at maximum efficiency providing greater distance of commute and longer battery life. Recent research focuses on the control of AUVs remotely through either Internet of Things or acoustic control.