Walking setup used to power upper limb prostheses in the works

August 29, 2022
Walking setup used to power upper limb prostheses in the works

Scientists at Rice University (Rice) in Texas are developing a pneumatic “extra limb” that will be powered by the wearer’s footsteps. Prosthetics are incredibly useful to those with disabilities – they could, however, do without the bulky and heavy batteries that often come with these devices.

An experimental system currently being developed by a Rice team led by Asst. Prof. Daniel Preston from the Department of Mechanical Engineering, graduate student Rachel Shveda, and postdoctoral associate Anoop Rajappan, is expected to do just that.

The lightweight, inexpensive, machine-washable setup incorporates three main components: a set of open-cell-foam-filled textile pumps worn like insoles inside the wearer’s shoes; an energy storage bladder worn around their waist; and an inflatable textile “arm” that stays curled around one hip when not in use. Air hoses connect the pumps to the bladder, and the bladder to the arm.

The system works like this: as the user walks and compresses the pumps with their body weight, those pumps push air up into the bladder, until it’s fully inflated. With the press of a button, the bladder releases some of that air into the arm, causing it to extend out from the body.

Another button-press releases air from the arm when it needs to curl around and pick up an object. A silicone rubber coating helps it maintain a steady grip on the object, allowing the user to carry it from one location to another.

Finally, when the user wishes to release the object, they just release some air back into the arm, causing it to extend back out again.

In another version of the system, walking causes the bladder to release air into a bellows-like apparatus worn over the armpit beneath one of the wearer’s arms. As that bellows inflates and expands, it raises the arm, letting the wearer lift up to 10 lb. (4.5 kg) without using any arm-muscle power.

The Rice team are now working on lowering the profile of the system, and on giving it the ability to predict the wearer’s actions, so not every step of those actions has to be manually activated.

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Category: Technology & Devices

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