In the study, the scientists sought to resolve a previous conundrum. A cable-driven eye could produce the eye's kinematics, but rigid servomotors would not allow researchers to test the hypothesis for the neurological basis for eye motion.
Some measure of flexibility could be used in software with traditional actuators, but it depended largely on having a continuously variable control signal and it could not show how flexibility could be maintained with quantized actuation corresponding to neural recruitment phenomena.
"Each muscle-like actuator consists of a piezoelectric material and a nested hierarchical set of strain amplifying mechanisms," said Ueda. "Unlike traditional actuators, piezoelectric cellular actuators are governed by the working principles of muscles - namely, motion results by discretely activating, or recruiting, sets of active fibers, called motor units.
"Motor units are linked by flexible tissue, which serves a two-fold function," said Ueda. "It combines the action potential of each motor unit, and presents a compliant interface with the world, which is critical in unstructured environments."
The Georgia Tech team has presented a camera positioner driven by a novel cellular actuator technology, using a contractile ceramic to generate motion. The team used 16 amplified piezoelectric stacks per side.
The use of multiple stacks addressed the need for more layers of amplification. The units were placed inside a rhomboidal mechanism. The work offers an analysis of the force-displacement tradeoffs involved in the actu
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Georgia Institute of Technology Research News