Researchers from Georgia Tech recently presented novel, bio-inspired camera motion technology at the IEEE International Conference on Biomedical Robotics and Biomechatronics in Rome, Italy. The camera’s eye movement is activated using a complicated piezoelectric mechanism that involves many small actuators that work in synchronicity much like muscle cells in our own eyes.
The research team hopes that the new technology, which is also considerably more energy efficient than common motor driven camera actuators, will be useful for a variety of medical applications such as MRI guided surgery, rehabilitation, and all kinds of assistive robots of the future.
Some details of the new technology:
“For a robot to be truly bio-inspired, it should possess actuation, or motion generators, with properties in common with the musculature of biological organisms,” said Schultz. “The actuators developed in our lab embody many properties in common with biological muscle, especially a cellular structure. Essentially, in the human eye muscles are controlled by neural impulses. Eventually, the actuators we are developing will be used to capture the kinematics and performance of the human eye.”
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 cellular actuator concept developed by the research team was inspired by biological muscle structure that connects many small actuator units in series or in parallel.
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.
“Each muscle-like actuator has a piezoelectric material and a nested hierarchical set of strain amplifying mechanisms,” said Ueda. “We are presenting a mathematical concept that can be used to predict the performance as well as select the required geometry of nested structures. We use the design of the camera positioning mechanism’s actuators to demonstrate the concepts.”
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.
“Our research shows a two-port network model that describes compliant strain amplification mechanisms that increase the stroke length of the stacks,” said Schultz. “Our findings make a contribution to the use of piezoelectric stack devices in robotics, modeling, design and simulation of compliant mechanisms. It also advances the control of systems using a large number of motor units for a given degree of freedom and control of robotic actuators.”