Underwater exoskeletons could help divers use less air and move more efficiently
Chinese Academy of Sciences Headquarters
image:
A scuba diver wearing the PEAKED soft underwater exosuit, which provides lower-limb assistance during underwater locomotion.
view moreCredit: Image by SIAT
Scuba diving places heavy demands on the human body. Divers must constantly overcome water resistance while carrying breathing equipment and other gear, and their underwater time is ultimately limited by both physical endurance and the amount of breathing gas they can carry.
Now, a team of Chinese researchers led by Prof. WU Xinyu at the Shenzhen Institute of Advanced Technology (SIAT) of the Chinese Academy of Sciences (CAS) has developed wearable underwater exoskeletons that may ease this burden. By assisting divers’ leg movements, these robotic systems can reduce physical effort while allowing divers to retain control over their movements and decisions and perceive their surroundings directly.
The study was published as a Focus article in Science Robotics on October 21.
One of the team’s representative systems is PEAKED, a soft underwater hip exosuit designed to assist both hip flexion and extension. The system supports several common underwater movement patterns, including flutter kicking, frog kicking, and underwater walking. Unlike rigid robotic structures, PEAKED uses a compliant design that allows large and natural lower-limb movements while still providing mechanical assistance.
In previous human experiments, PEAKED reduced respiratory minute volume by 29.77% during flutter kicking, 25.70% during frog kicking, and 18.35% during underwater walking. Respiratory minute volume measures the volume of gas breathed per minute. These results suggest that underwater exoskeletons may reduce divers’ ventilatory demands during different forms of underwater locomotion.
The researchers also point out that underwater exoskeletons cannot simply copy designs developed for walking or running on land. Buoyancy reduces the need to support body weight, while water resistance acts throughout much of the leg movement. This makes bidirectional assistance especially important during kicking.
As a result, the structure of the device, the joints being assisted, and the timing and direction of assistance all need to be matched to specific underwater movements. Practical systems must also work together with scuba tanks, ballast, and other diving equipment, remain waterproof under pressure, and allow rapid removal in an emergency.
Looking ahead, the researchers highlight two promising directions: personalized assistance and posture stabilization. Future systems incorporating advances in these areas could automatically adjust assistance to different divers, movement patterns, and task demands, while also helping maintain body stability underwater.
According to the researchers, these potential advances could help transform underwater exoskeletons from simple assistive devices into intelligent wearable systems that help divers move more efficiently and undertake demanding underwater tasks with less physical effort.
Journal
Science Robotics
Article Title
Reducing energy and air consumption in scuba diving with underwater exoskeletons
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