An exoskeleton device that increases walking efficiency without external power supply is developed

Various types of instruments that aid human walking are developed, but it is indispensable to borrow the power of electricity when trying to obtain higher effect. Although it is mid-common sense that it is necessary to rely on external energy such as electricity in order to improve efficiency, scientific journalsNatureIn the paper published in the paper, it is clear that we succeeded in developing exoskeleton type devices that realized up to 10% increase in walking efficiency without using any electric power.

Reducing the energy cost of human walking using an unpowered exoskeleton: Nature: Nature Publishing Group
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14288.html

An unpowered exoskeleton decreases the energy required for walking | Ars Technica
http://arstechnica.com/science/2015/04/an-unpowered-exoskeleton-decreases-the-energy-required-for-walking/

The appearance of the developed exoskeleton device looks like this. Although the body made of carbon fiber has a structure similar to ordinary prosthesis, one arm extends rearward from the base part covering the heel comfortably, and a spring and a rope, and a calf part through a special clutch This is the most important mechanism for producing high efficiency.


Here is a picture etc actually attached. As shown in the right picture, the spring is in the extended state with the back leg stretched, it seems that the structure is configured to support the motion of kicking the ground forward by the spring returning force. Clutches located around the back of the knee allow rotation only in certain directionsRatchet mechanismIt controls the expansion and contraction of the spring to control the accumulation and release of energy.


You can watch the video showing the state of walking experiment with this device on YouTube.

2013 01 01398D Supplementary Video 1 Walking with the exoskeletons - YouTube


Male subjects walking on the walking machine. It is the moment of kicking out the left foot from now on.


Take the left foot forward ... ....


At the timing when the heel arrives at the ground, the ratchet mechanism turns on, and only the winding of the rope becomes possible.


By winding up the rope a little ......


The ratchet is locked and the rope and the spring are taut. At this time, the heel is in a state where most of the weight is on the ground completely.


As the foot moves backwards, the spring is stretched and the tension is applied.


The tension of the spring reaches the maximum when the foot strokes to the back. By using this force, it supports the action of lifting the heel by kicking the ground with a toe.


When the heel lifts, the ratchet is unlocked and it becomes free.


Then, the spring and the rope are in a state where no force is applied, so there is no way to disturb the walking movement at all. By repeating this series of cycles, this device helps human's walking movement and realizes efficient walking.


The research team examined how much the metabolic energy consumption of humans is reduced by this exoskeleton device. As a result, it turned out that good results are obtained when the weight of the main body is sufficiently lightweight. In addition, it is understood that the strength of the spring also has a great influence on efficiency. As we gradually raise the spring from the weakest state, the metabolic rate has decreased to a certain level and the efficiency got higher, but as we further strengthened the spring, the metabolism increased conversely this time is. This means that extra energy was consumed to stretch the spring that was too strong, which means that it is important to optimize the strength of the spring for efficient walking It is supposed to do.

As a result of the experiment, it was found that the energy required for walking was reduced by 7.3% (± 2.6%) on average on the device, which means it is a device comparable to a general auxiliary device using a power supply . If you think carefully, raising efficiency without using external energy can be said to be the ultimate device that also passes to a perpetual institution, but this is still an inefficient part remaining in the way people walk It may prove that it was being done.

In the future, it was a research result that attracted attention as to how the walking efficiency was improved.