New Delhi | Researchers at the Indian Institutes of Technology (IIT) Mandi and Palakkad have developed a marine robot that can cater to real-time problems and reduce maintenance cost and death risk for underwater operation scenarios.

The research which was partially funded by the Naval Research Board (NRB) of Defence Research and Development Organization (DRDO) has been published in two journals-- Journal of Intelligent and Robotic Systems, and Ocean Engineering.

The state-of-the-art robot has been developed for meticulous underwater monitoring and inspections, promising heightened efficiency, minimised risks, and potential cost savings, the researchers said.

The Earth's surface is covered approximately 71 per cent by water, with the oceans holding about 96.5 per cent of all the Earth's water, where only a tiny percentage of the ocean floor and the submerged ecosystem is known to man.

"As understood from history, the ocean interior has been mainly observed using instruments lowered from research ships," Jagadeesh Kadiyam, Assistant Professor, Centre for Artificial Intelligence and Robotics at IIT Mandi, told PTI.

Kadiyam, a co-author of the stydy, said typical ship cruises lasted a month or two, therefore making the detailed monitoring of oceans limited.

"It is often said that ocean variables do not wait for the ship to come for measurements," he pointed out.

"This problem of under-sampling and the relatively high cost of these observation platforms demands technologies that could provide longer observation times at a lower cost through spatial and temporal density," Kadiyam said.

"Similarly, infrastructure safety is a global concern with ageing dams and increased environmental stresses necessitating more advanced inspection methods. Traditional inspection approaches often involve human divers, which can be risky, time-consuming and expensive," he said.

"Integrating marine robots into dam inspection procedures offers a safer, cost-effective, and technologically advanced solution,” he added.

Kadiyam explained that the recent open-water reservoir field trials signifies a considerable advancement in the maturity of underwater vehicle technology.

"Our research focuses on the prototype development and performance investigations of an underwater vehicle for intervention and inspection applications. A novel framework has been designed and implemented to cater to the various missions in the oceans and inland waters," he said.

Several simulations and experimental outcomes have proven the system's capabilities in the presence of external disturbances such as water currents and varying payloads, the professor said.

The number of submerged structures is steadily increasing due to the advent of new technologies and the rapid expansion of existing infrastructure for defence or civil purposes. Therefore, it is an essential routine to check, maintain, and repair these structures.

Earlier, the jobs underwater were done by human divers, which posed a long-term health effect but now underwater vehicles can be deployed to reduce human intervention.

Santhakumar Mohan, Professor at IIT-Palakkad highlighted the challenges faced by researchers in developing marine robots.

"From research point of view, the marine robotics community faces numerous challenges due to the uncertain aquatic environment and disturbances. Communication underwater is still tricky as it predominantly depends on acoustics since the radio waves are hard to pass through the water medium. As this is a niche area, the component cost of the vehicles is also high," Mohan said.

"Other issues include waterproofing, choice of non-corrosive materials, and high-pressure operations underwater. Therefore, marine robotic technology will take time to get matured, unlike the vehicles used on land and in the air. Our research focuses on developing systems and designing advanced controls to increase the robot's accuracy, precision, efficiency, and performance," he added.

Various fixed-actuator or thruster setups are commercially available in the market, but surprisingly, the choice of optimised thruster configuration for a specific application is not available so far. The location and arrangement of thrusters and the number of thrusters can change the vehicle's performance in overall.

"Our research provides valuable insight into choosing a specific configuration based on the mission in the presence of unknown underwater disturbances. A prototype test vehicle has been developed and was rigorously tested using simulations and real-time experiments to demonstrate its effectiveness for various underwater operations.

"The deployment of these vehicles could play a crucial role in various applications, such as hydroelectric infrastructure inspection (inspecting submerged structures), environmental monitoring of water bodies (early detection of environmental issues), and search and rescue operations,” Mohan said.