Swumanoid, a humanoid robot developed in Japan by the Tokyo Institute of Technology, is capable of reproducing the complex movements of the crawl, back crawl and butterfly. The aim: to measure the efficiency of the movements and the hydrodynamics to improve the technique of the swimmers. One of the creators answered Futura-Sciences' questions.
Finding the perfect move to swim better and faster. This is the quest of the top swimmers who have once again distinguished themselves in these Olympic Games from London. For these outstanding athletes, performance is hidden in the details and every find can give a decisive advantage over the competition. To achieve this, sports research is primarily based on the analysis of movement through video. The problem with this empirical method is that it requires swimmers to be able to reproduce their movements in the water with precision and consistency. Moreover, it is very difficult to take measurements using sensors that may be distracting to the athlete.
The solution may come from Swumanoid...a humanoid swimming robot designed by two researchers at the Tokyo Institute of Technology, Motomu Nakashima and Chung Changhyun. Equipped with four articulated limbs driven by 20 waterproof electric motors, it is capable of reproducing the specific movements of three swims (the crawl, the back crawl and the butterfly) and provides reliable information on the motive force generated by the hands, arms, legs and the resistance of the body in the water. Swumanoid was built at half the human scale, but the volume and weight of each of its parts were calculated to reproduce the proportions and gravity. It weighs a total of 5.5 kg for a height of 900 mm and a width of 270 mm. The robot's body and limbs are made of acrylonitrile butadiene styrene (ABS) - a robust plastic - using a 3D printer.
The Swumanoid Joint
The electric minimotors have been modified to fit into the narrowest parts of the joints (arms, legs, ankles). Twelve motors ensure the complex movements of the arms. In total, Swumanoid has 21 degrees of freedom: 14 for the upper limbs of which 4 for the arms and 2 for each shoulder and 7 degrees for the lower limbs. "One of the main difficulties we encountered was the wide variety of movements at the shoulder junction. To solve this, we added an extra joint on each shoulder to reproduce scapular retraction," Motomu Nakashima told Futura-Sciences.
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The Japanese research team used a 3D scanner to capture the movements of a competitive swimmer and then used it to teach Swumanoid how to swim. The robot is not yet autonomous, it is remotely controlled by a computer. Swumanoid is far from achieving the fluidity of human movements, but the result is rather impressive when you see it swimming the crawl, faithfully reproducing the gestures.
Video presentation of Swumanoid, the swimming robot developed by the Tokyo Institute of Technology. © DigInfo, YouTube
Swumanoid, lifeguard at sea?
"With this robot, we can measure the differences between the driving forces of the various movements, even if the differences in gestures are minimal. So that we can know which gesture is effective in maximizing the driving force," adds Professor Nakashima. Nakashima sees many opportunities for Swumanoid to one day become a lifeguard who can help swimmers in difficulty. Advances in articulation and movement could also pave the way for new underwater robots.
However, there is still a long way to go. For the moment, Swumanoid is still very slow and can only work with a series of support arms. "Our future goals are to perform autonomous tests without supports and to develop an algorithm to control posture during swimming," says Motomu Nakashima. According to him, it will take another 10 to 15 years before such a robot will be able to act as a lifeguard at sea.