CHENNAI: With robotics emerging as a major area of focus for military applications, especially the bio-inspired ones, countries across the globe are investing heavily in this domain. But, not many have tasted success so far.
However, Santhosh Ravichandran, an MS student specialising on machine design in the Department of Mechanical Engineering at IIT Madras, has developed a first-of-its kind turtle shaped Robotic Underwater Vehicle (ROV) with bio-inspired propeller similar to a dolphin fin in just three months.
Called ‘Duli’, a Sanskrit name for a turtle, it had immediately caught the attention of Defence Research Development Organisation (DRDO). The robot has unique hydrodynamics with exceptional energy efficiency and camouflage abilities suited for carrying out of underwater SEAL operations. It can do visual inspection withstanding the undercurrent of the ocean, it is claimed.
Project supervisor and associate professor at IIT-M Prabhu Rajagopal said a DRDO lab was in talks. “They wanted us to install their own sensors and do certain modifications to suit military requirements,” he said.
Santhosh said the currently available underwater robots are predominantly operated with mechanical thrusters, which gives only 30% energy efficiency (read output to input), while Duli with bio-inspired flap movement will give 70% efficiency similar to biological organisms like dolphins.
“We have exhibited the prototype at Underwater Interventions expo in United States in February this year. US navy, which is a participant, was all praise for our product and actually am in touch with them for any technical assistance. They also now plan to start a bio-inspired robotics programme,” Santhosh said.
Rajagopal, who is also the director of Plany’s Technologies, a spin-off start-up providing robotic services to port and shipping industry, said the product was still at preliminary stage and needed a lot of on-field testing to address several practical problems that might arise, but all the basics are covered. An autonomous version would be ready in a few months.
The novelty of the Duli is bio-inspired tail that could be used for rapid long motion which is eco-friendly. It will do sensitive jobs like surveying coral reefs without causing any disturbance to marine life. The mechanical pectoral thrusters are used only for manoeuvring. Usually bio-inspired designs suffer from complexities in control systems such as under-actuation, lower manoeuvrability.
Rajagopal said optimal shape of the caudal fin and its driving mechanism is currently being researched using computational fluid dynamics (CFD) simulations validated by experiments. Efforts are on to improve the hydrodynamic and mechanical dynamic performance of the vehicle with an improved hull design for robustness in a wide variety of applications.