03/24/2018 / By Edsel Cook
Not satisfied with the nature-inspired soft robots they’ve already created, a Harvard University (Harvard) research team is planning to install embedded sensors that will let their creations sense movement, pressure, touch, and temperature like living organisms do. In fact, reported an AlphaGalileo article, they based the idea upon the sensory capabilities of the human body.
Previous Harvard-designed robots can crawl, swim, hold delicate objects, and aid a beating heart. However, none of them could sense and respond to their surroundings.
That’s going to change with the new manufacturing platform developed by researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Wyss Institute for Biologically Inspired Engineering (Wyss Institute).
“Our research represents a foundational advance in soft robotics,” said Ryan Truby, primary author of the paper. According to him, the manufacturing platform makes it easy to integrate complex sensor systems into soft robots.
The joint team published their paper in the journal Advanced Materials. (Related: FREAKY: Boston Dynamics’ SpotMini robo-dogs can coordinate, navigate, open doors, climb stairs and even load the dishwasher.)
Most sensors have rigid shapes. This holds true for those employed in conventional electronics. This structural inflexibility hampers the integration of sensors into soft robots.
The Harvard researchers found a way around this problem through embedded 3D printing techniques. They used an organic ionic liquid-based conductive ink to 3D-print the sensors into the elastomer matrices that make up most soft robots.
“To date, most integrated sensor/actuator systems used in soft robotics have been quite rudimentary,” explained Michael Wehner, co-author of the SEAS paper on soft robots with embedded sensors.
“By directly printing ionic liquid sensors within these soft systems, we open new avenues to device design and fabrication that will ultimately allow true closed-loop control of soft robots.”
The embedded 3D printing technique was developed by Jennifer Lewis, the professor of Biologically Inspired Engineering at SEAS and a Core Faculty Member of the Wyss Institute.
“This work represents the latest example of the enabling capabilities afforded by embedded 3D printing – a technique pioneered by our lab,” explained Lewis.
Researcher Truby says Lewis’ embedded 3D printing method allowed the integration of flexible sensors into soft robots, greatly increasing their flexibility and functionality.
“This new ink combined with our embedded 3D printing process allows us to combine both soft sensing and actuation in one integrated soft robotic system,” he said. (Related: Would you allow an Amazon robot inside your house? They’ve patented a “postman” bot to unlock doors for delivery, pickup.)
To test the sensors, the team 3D-printed a soft robotic gripper comprised of three soft digits called actuators. A number of contact sensors were embedded into the robot’s elastomer matrix to detect light and deep touches.
The newly-manufactured robot gripper underwent tests to determine its ability to sense inflation pressure, curvature, contact, and temperature.
Co-author Robert Wood cited two main constraints on soft robotics. Conventional molding techniques limit the geometric shapes possible, while material selection stunts design choices for commercial 3D printing.
“The techniques developed in the Lewis Lab have the opportunity to revolutionize how robots are created – moving away from sequential processes and creating complex and monolithic robots with embedded sensors and actuators,” Wood said.
The next goal for the Harvard researchers is to add machine learning to the mix. They plan to train the soft robots to grasp various objects with different sizes, shapes, surface textures, and temperatures.
Find out more articles on soft robotics at Robotics.news.