After millions of years of evolution, your feet are still not perfectly energy efficient. Enter exoskeletons. Researchers have created a new boot that, unlike other exoskeletons, makes walking more efficient without an extra battery or power source.
The boot contraption reduces the energy it takes to walk by about 7 per cent. That may not sound like a lot, but keep in mind this is without a bulky battery pack for power. And it works differently from exoskeletons that give you superhuman strength, which are really a matter of expending less energy over a longer period of time, so total energy expenditure is the same.
Here, it's a more subtle process of finding tiny inefficiencies and correcting them. It is human walking, optimised. For example, one inefficiency is that our muscles use energy even when they're locked in place. Not so for a mechanical clutch. Davide Castelvecchi explains in Nature:
The researchers' exoskeleton structures, built of lightweight carbon-based materials, have a spring that connects the back of the foot to just below the back of the knee, where it attaches with a mechanical clutch. When the Achilles tendon is being stretched, the clutch is engaged and the spring, rather like an additional tendon, stretches and helps to store energy. After the standing leg pushes down, unleashing elastic energy, the clutch releases and absorbs the slack in the spring, in preparation for the next cycle..
The downside though, as you can hear in the video below, is that you sound like a robot squeaking through the woods. The researchers hope to refine the boot, so that energy gains apply regardless of speed and terrain. No word on the squeakiness though. [Nature: Study, News]
Picture: Stephen Thrift