Soft-bodied robots move via pneumatic "muscles" that are selectively inflated or deflated. And while the muscles themselves may be soft and squishy, they're usually hooked up to hard, unwieldy pumps. A new pump, however, is both small and flexible.
Developed by scientists at the University of Bristol, the 5-gram electro-pneumatic pump is about the size and shape of a credit card. Not only is it thin and bendable, but it's reportedly also inexpensive and easy to manufacture.
The experimental device takes the form of a flat pouch, with an air tube attached to one side. Sealed within that pouch is an air pocket, and a small amount of a dielectric liquid. When an electrical current is applied to electrode sheets on either side of the pouch (and thus on either side of the liquid), a process known as dielectrophoretic liquid zipping occurs.
As part of this process, the two electrodes sheets compress the pouch by being drawn in toward one another – they start at one side of the pouch and move toward the other. This action causes the air within the pouch to be squeezed out, going through the tube and into an attached pneumatic muscle, thus expanding it. Once the electrical current is shut off, the pouch "unzips" and opens back up, drawing the air back in from the now-contracting muscle.
By varying the voltage applied to the electrodes, it's possible to control the strength and range of the muscle-activated movements.
It is hoped that once the technology is developed further, it could be used not only in robots but also in assistive clothing that helps physically challenged wearers move their arms or legs.
A paper on the research, which is being led by Prof. Jonathan Rossiter, was recently published in the journal Science Robotics. The electro-pneumatic pump is demonstrated in the video below.
Source: University of Bristol
