Using piezoelectric materials, researchers have replicated the muscle motion of the human eye to control camera systems in a way designed to improve the operation of robots. This new muscle-like action could help make robotic tools safer and more effective for MRI-guided surgery and robotic rehabilitation.
Piezoelectric materials expand or contract when electricity is applied to them, providing a way to transform input signals into motion. This principle is the basis for piezoelectric actuators that have been used in numerous applications, but use in robotics applications has been limited due to piezoelectric ceramic’s minuscule displacement.
The Georgia Tech team has developed a lightweight, high speed approach that includes a single-degree of freedom camera positioner that can be used to illustrate and understand the performance and control of biologically inspired actuator technology. This new technology uses less energy than traditional camera positioning mechanisms and is compliant for more flexibility.
The scientists’ research shows mechanisms that can scale up the displacement of piezoelectric stacks to the range of the ocular positioning system. In the past, the piezoelectric stacks available for this purpose have been too small.
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.
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 actuator design and shows how to find geometry that meets the requirement of the camera positioner, said Schultz.
This story is reprinted from material from Georgia Tech, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.