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Completely unfolded, the milliDelta with 12 mm-by-15 mm-20 mm roughly compares to a cent piece, and uses piezoelectric actuators and flexural joints in its three arms to control high-frequency movements of a stage on top. Credit: Wyss Institute at Harvard University

Inspired by origami, researchers have created a miniaturized Delta robot that could be compatible with a range of micromanipulation tasks in manufacturing and medicine.

A team of researchers from Harvard University have designed a new robot called the milliDelta robot, by integrating a microfabrication technique with high-performance composite materials that can incorporate flexural joints and bending actuators to enable the robot to operate with high speed, force and micrometer precision.

Inspired by pop-up books and origami, the researchers developed a micro-fabrication approach called pop-up microelectromechanical systems (MEMS) that enabled the assembly of robots from flat sheets of composite materials and creates a Delta robot that is 15 mm-by-15-mm-by-20-mm.

“The physics of scaling told us that bringing down the size of Delta robots would increase their speed and acceleration, and pop-up MEMS manufacturing with its ability to use any material or combination of materials seemed an ideal way to attack this problem,” Robert Wood, the Charles River Professor of Engineering and Applied Sciences at the School of Engineering and Applied Sciences (SEAS), said in a statement. “This approach also allowed us to rapidly go through a number of iterations that led us to the final milliDelta.”

Delta robots are used in many industrial processes, including pick-and-place assemblies, machining, welding and food packaging because of their high precision and speed. Delta robots use three individually controlled and lightweight arms to guide a platform to move fast and accurately in three directions.

The platform is used as a stage—similar to the ones being used in flight simulators—or coupled to a manipulating device that can grasp, move and release objects in prescribed patterns. However, attempts to shrink Delta robots in the past has been fruitless.

The new design incorporate a composite laminate structure with embedded flexural joints that approximate the more complicated joints found in large scale Delta robots.

“With the help of an assembly jig, this laminate can be precisely folded into a millimeter-scale Delta robot,” first-author Hayley McClintock, a Wyss Institute Staff Researcher on Wood's team, said in a statement. “The milliDelta also utilizes piezoelectric actuators, which allow it to perform movements at frequencies 15 to 20 times higher than those of other currently available Delta robots.”

The team also demonstrated that the milliDelta can operate in a workspace of about seven cubic millimeters and can apply forces and exhibit trajectories, that when coupled with its high frequencies, could make it suitable for micromanipulations in industrial pick-and-place processes and microscopic surgeries ,including retinal microsurgeries.

To test this possibility, the researchers explored the robot as a hand tremor-cancelling device.

“We first mapped the paths that the tip of a toothpick circumscribed when held by an individual, computed those, and fed them into the milliDelta robot, which was able to match and cancel them out,” co-first author Fatma Zeynep Temel, Ph.D., a SEAS Postdoctoral Fellow in Wood's team, said in a statement.

The new robot could be added to existing robotic devices or developed as a standalone device.

“The work by Wood's team demonstrating the enhanced speed and control of their milliDelta robot at the millimeter scale opens entirely new avenues of development for industrial and medical robots, which are currently beyond the reach of existing technologies,” Wyss Institute Founding Director Dr. Donald Ingber, Ph.D., who is also the Judah Folkman Professor of Vascular Biology at HMS and the Vascular Biology Program at Boston Children's Hospital, as well as a professor of Bioengineering at SEAS, said in a statement. “It's yet another example of how our Bioinspired Robotics platform is leading the way into the future.”      

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