The SEAS-colada is the trendiest summer drink right now. To make it, you’ll need gin, pineapple juice, coconut milk, and a special soft peristaltic pump created by Robert Wood, a professor at Harvard’s School of Engineering and Applied Sciences.
But don’t worry, you’ll soon be able to find this pump outside of the lab.
Wood and his team have been working on solving a major problem in soft robotics: how to replace bulky and rigid power components with soft alternatives. They’ve been developing soft versions of valves and sensors, and now they’ve created a compact and versatile pump.
In fluid-driven robotic systems, pumps control the pressure or flow of the liquid that powers the robot’s movement. Most pumps available today for soft robots are either too big or rigid to fit onboard, not powerful enough, or only work with certain fluids.
The pump created by Wood’s team is different. It’s small, powerful, and can pump a variety of fluids with different viscosities, like gin, juice, and coconut milk. It can even power soft haptic devices and a soft robotic finger.
This pump opens up a world of possibilities for soft robots in various industries, including food handling, manufacturing, and biomedicine.
The research was recently published in Science Robotics.
The Power of Peristaltic Pumps
Peristaltic pumps are widely used in industry. They work by compressing a flexible tube with a motor, creating a pressure difference that pushes liquid through the tube. These pumps are especially useful in biomedical applications because the fluid doesn’t come into contact with the pump’s components.
“Peristaltic pumps can handle liquids with different viscosities, suspensions, and fluids like blood, which are challenging for other types of pumps,” said Siyi Xu, the first author of the study.
Xu and the team used electrically powered dielectric elastomer actuators (DEAs) as the motor and rollers for the pump. These soft actuators have high power density, are lightweight, and can run for a long time.
A Compact and Powerful Solution
The team designed an array of DEAs that work together, compressing a tiny channel in a programmed sequence to create pressure waves.
The result is a small pump that can fit on a soft robot and provide enough power for movement. It also allows the user to control the pressure, flow rate, and direction of the liquid.
“By adjusting the input voltages and the outlet resistance, we can change the pump’s output from a continuous flow to droplets,” explained Xu. “This feature could be useful not only in robotics but also in microfluidic applications.”
According to Wood, most soft robots still have rigid components in their drivetrain. The goal of this research was originally to find a soft alternative to the pump, but it turned out that these compact soft pumps have even more potential. They could be used in biomedical settings for drug delivery or implantable devices.
The study was co-authored by Cara M. Nunez and Mohammad Souri and received support from the National Science Foundation.
Watch the video of the pump in action: https://youtu.be/knC9HJ6K-sU