While some humanoid robots we've reported on recently can walk up stairs or fight fires, researchers at the Tokyo Institute of Technology have developed a "swumanoid" robot they say faithfully mimics human swimming motions for applications that may include more streamlined swimsuits or methods for improving the performance of competitive swimmers. Other uses that come to mind include robots as an aid in physical therapy.
The half-scale swumanoid incorporates 20 waterproof motors that are controlled by a computer to mimic the actions of human swimmers. Tokyo Tech researchers Chung Changhyun and Motomu Nakashima say they developed the robot by carefully analyzing real human swimmers' body movements.
Previous research relied on analyzing video images of human swimmers to monitor their movements, but the researchers say this led to the problem of how to reproduce those movements. That's because this approach depends on the ability of the swimmers to recreate their own movements precisely. It also depends on the ability of researchers to make accurate measurements of the forces that are acting on swimmers' bodies while they are in motion. Both of these tasks have proven extremely difficult to accomplish.
The half-scale swumanoid swimming robot incorporates 20 waterproof motors that are controlled by a computer to mimic the actions of human swimmers. (Source: Tokyo Institute of Technology)
Nakashima and his colleagues at Tokyo Tech previously developed the SWUM (SWimming hUman Model) swimming human simulation model for analyzing the whole-body dynamics of swimmers. Data for body geometry, joint motion, and specific analysis settings are given. The model estimates the fluid force acting on the swimmer's body, solves the equations of motion of the rigid human body, and computes the absolute motion of the whole human body. The developers have created a free implementation of the model called "Swumsuit" that can be downloaded here.
Two of the major issues to resolve have been reducing body resistance to movement through water and increasing the driving force caused by the swimmers' hands and feet. The swumanoid robot enables control of the precise movements and driving forces of the robot swimmer. The robot is half the size of an adult human, but has the same proportions and external features. Twelve of the 20 motors actuate the movements of the arms and one motor turns the waist. Each arm has six degrees of freedom, while the shoulder has four degrees and the elbow has two. Extra joints have been added to the shoulder to reproduce the retraction of the shoulder blade.
The swumanoid demonstrated the accuracy of both hardware and software models by its performance in reproducing the arm motions of the front crawl, which is the most complicated swimming stroke.
Changhyun and Nakashima say that in the future, they want to produce much faster swumanoids and also analyze those robots' movements to develop high-speed swimwear.
As someone who has spent more swimming hrs in the water than 1000 average people combined I found this a poor use of everything. No wonder Japan is falling far behind.
Next the human form and especially this unit is about the worst you can get for propulsion movement in the water as can exert little force with a very large amount of drag.
I hunt fish. etc for food underwater, no scuba, just snorkeling to 50' down and even with fins I'm almost the slowest fish down there except the poison ones. Only by tactics is one able to get the fish one wants to eat like sneaking around a coral head, etc and surprising them.
I think the point of optimized swimwear is to not slow down the competitive swimmer. Any clothing does so: it introduces drag. Regarding arm movements, it's important to remember that this hardware is a first effort, although the simulation software is not, and the researchers point out that getting the shoulder movement down was the hardest part, as it's the most complex. It's a WIP.
I think it would be a good idea under certain conditions like a bad weather where it's almost impossible to send someone to rescue, but I think the legs in water are inefficient and for that a propeller for lower body is much better in many aspects. The upper body with limbs is a good idea if you are trying to grab someone or something from the water. Nice work though!
This is a great start. Agree with Beth that its movements are quite choppy. I also noticed that it has the advantage (or disadvantage for good human swimming simulation) of not having to raise its head above water to take a breath. We all could swim a bit better if breathing was unnecessary. Seems like simulating taking a breath and seeing where you are going must be a part of this at some point.
Beth. I agreee with you. When I first saw the video, the first thing that I noticed was that the movement was choppy. Why they didn't put sensors on a swimmer to provide a model is beyond me.
The other thing that I noticed was that the arm movement was wrong. You have to do two things at the same time which the robot seems to not be able to do. You pull down one arm at the same time you move the second arm up. It appears that they move the one arm up AND THEN move the other arm down and back.
I would bet that if they put it in water that it would sink which is why the video doesn't show the robot actually swimming.
Using the robot to enable competitive swimwear--that's likely to open up the can worms of too much reliance on technology and not enough on performance of the human body. Nevertheless, as Ann points out, the fact that they put all this energy into developing the full swimmer's body model is exciting and an effort that could have applicability in numerous places.
Rescue robots are currently being developed mostly for use on land. Based on some other nautical robot designs, I'd guess that rescue robots developed for use in the water would not replicate the details of human anatomy or swimming movements, as the swumanoid does, since human swimming movements aren't the most efficient way to move through water. The swumanoid has been optimized for those last two functions, but rescue robots are optimized for speed and strength, such as lifting or pulling heavy objects. For example, the Hawkes Remotes T-Series is small, compact and provides enough torque to lift 220 lbs: http://www.designnews.com/author.asp?section_id=1386&itc=dn_analysis_element&doc_id=246206&image_number=11
Thanks, gsmith120. That's an interesting idea, to combine these swimming abilities with some of the abilities of the robots shown in the nautical robot slideshow. The team stated that its next steps are to develop faster robots to better emulate competitive swimmer's movements and also to come up with swimwear optimized for high-speed swimming.
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