From the point of view of the layman, climbing up is always more difficult than going down, but physicists say that everything is much more complicated. The muscles of the legs work both during the ascent and during the descent, but in the first case, almost all the energy expended is converted into useful work. While going down we scatter it in vain, only so as not to fall. And this upsets innovators.
A team of scientists from Georgia Tech Institute and Emory University has developed a device to recover energy as a person moves up stairs. This is a set of spring loaded guides fitted with motion sensors. When a person descends, he lowers the plate with his own weight and cocks the spring, and when lifting, the lock opens and pushes the leg up.
The work of the system is tied to the steps of the users, the plates move cyclically and only along the height of one step, so that the staircase always retains its shape. Sensors help distinguish the movement down from the path up, the force of the springs is matched to gently push the person's legs so that he does not lose balance. Certainly, it will take some practice and such recuperators cannot be installed absolutely everywhere - old fixed ladders are safer.
Georgia Tech's calculations give the following numbers: the system collects 26% of the energy when moving down and makes it 37% easier to climb. Not the most outstanding indicators, in comparison with the same escalator, but such recuperator ladders would be useful in hospitals, to help pregnant women and patients in rehabilitation. They can be installed directly on top of existing stairs, on a short-term or permanent basis.
The cost price of such an energy recuperator is almost symbolic, in comparison with the installation of any elevator or lift, and even more so on a personal order, in a private house. And they can become a help for the elderly and simply weak people who find it difficult to climb the stairs.