Better Prosthetics with Piezoelectrics

If this is successful, the research could result in better prosthetic movements and also provide instant electrical power for soldiers and others through the simple act of walking.

Pradeep Sharma, a UH mechanical engineering professor, is leading the team to create a “piezoelectric on steroids.” Piezoelectricity is the ability of some materials to generate an electric charge when placed under stress. Piezoelectrics are already involved for example in making an airbag deploy or a lighter producing a flame.

Although piezoelectrics are naturally occurring, they have their limits. If an application requires a level of energy conversion not found in a naturally occurring piezoelectric, a composite consisting of piezoelectrics and non-piezoelectrics must be made. Sharma and his team are creating piezoelectrics from man-made materials that have no piezoelectric property.

“If you press on a piezoelectric, or apply mechanical force, it will produce a voltage,” Sharma said. “Or, if you apply a voltage or electrical force to it, the object will bend or change its shape.”

The highly customizable piezoelectrics could enable the creation of prosthetics that come closer to offering both the flexibility and the strength of real limbs. Current prosthetic limbs face challenges in range and movement by the two types of naturally occurring piezoelectrics, ceramic and polymer.

“Ceramic piezoelectrics are very hard and brittle, and don’t allow for a lot of movement,” Sharma said. “They take a lot of electrical energy for a lot of motion. Polymers are better for large forces of motion, but don’t have a lot of strength. So, you can stretch adequately, but may not even be able to pick up an egg. Nature has given us some elements, and now we’re going beyond and designing materials from the ground up. We wanted to combine the best qualities of the two types of piezoelectrics, among other things.”; Source: University of Houston