Novel 3-D printing method embeds sensing capabilities within robotic actuators

Integrating sensors within soft robots has been difficult in part because most sensors, such as those used in traditional electronics, are rigid. To address this challenge, the researchers developed an organic ionic liquid-based conductive ink that can be 3D printed within the soft elastomer matrices that comprise most soft robots.

"To date, most integrated sensor/actuator systems used in soft robotics have been quite rudimentary," said Michael Wehner, former postdoctoral fellow at SEAS and co-author of the paper. "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."

Wehner is now an assistant professor at the University of California, Santa Cruz.

To fabricate the device, the researchers relied on an established 3D printing technique developed in the lab of Jennifer Lewis, the Hansjorg Wyss Professor of Biologically Inspired Engineering at SEAS and Core Faculty Member of the Wyss Institute. The technique -- known as embedded 3D printing -- seamlessly and quickly integrates multiple features and materials within a single soft body.

"This work represents the latest example of the enabling capabilities afforded by embedded 3D printing -- a technique pioneered by our lab," said Lewis.

"The function and design flexibility of this method is unparalleled," said Truby. "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."

To test the sensors, the team printed a soft robotic gripper composed of three soft fingers or actuators. The researchers tested the gripper's ability to sense inflation pressure, curvature, contact, and temperature. They embedded multiple contact sensors, so the gripper could sense light and deep touches.

"Soft robotics are typically limited by conventional molding techniques that constrain geometry choices, or, in the case of commercial 3D printing, material selection that hampers design choices," said Robert Wood, the Charles River Professor of Engineering and Applied Sciences at SEAS, Core Faculty Member of the Wyss Institute, and co-author of the paper. "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."

Next, the researchers hope to harness the power of machine learning to train these devices to grasp objects of varying size, shape, surface texture, and temperature.

The research was coauthored by Abigail Grosskopf, Daniel Vogt and Sebastien Uzel. It was supported it part by through Harvard MRSEC and the Wyss Institute for Biologically Inspired Engineering

Software aims to reduce food waste by helping those in need

"It is really heart wrenching to witness a mother in shabby and torn clothes, holding her baby, come to you and ask for help because her baby hasn't had anything to eat," Sharma said. "This I have witnessed often in my life."

Those interactions made an impression and heightened Sharma's awareness of hunger. When he moved to the U.S. in 2006 to continue his education, Sharma says he quickly recognized hunger was not just a problem in India. What he found most troubling was the amount of food wasted -- in the U.S. and India -- when so many people go without. After reading about elementary schools sending food packages home with students, Sharma decided to make hunger the primary focus of his research.

Given that 40 percent of the food produced in the U.S. is wasted, according to the USDA's Economic Research Service, Sharma wanted to find a way to divert excess food to those in need. It has taken almost three years for Sharma, a computer science expert and systems analyst in Iowa State University's Center for Survey Statistics and Methodology, and his collaborators to develop a software prototype -- eFeed-Hungers -- to do just that.

Ritu Shandilya, a third-year Ph.D. student in computer science; U. Sunday Tim, an associate professor of ag and biosystems engineering; and Johnny Wong, professor and associate chair of computer science, are all part of the research team. Their work is published online in the journals Resources, Conversation and Recycling, and Telematics and Informatics.

Making the connection

A program that distributes leftover food from catered events to the homeless in India inspired the vision for the online, interactive network, Sharma said. Restaurants, grocery stores and individuals can use the mobile-friendly software to post food they have to donate. Likewise, those in need can find nearby locations where food is available for pickup.

The researchers designed the software so donors take the food to a public place, such as a food pantry or church serving free meals, for pickup and distribution. It allows for one-time and recurring donations, so businesses or individuals do not have to enter their information repeatedly. Sharma says the interactive map makes it easy to search. Each location is marked with a flag to indicate the type of food, and hours it is available.

"We wanted to make it as simple as possible, so people will not hesitate to donate," Sharma said. "There is no scarcity of food. We see this as a way to take some of the food we're wasting and save it by providing a channel to get the extra food to the needy."

Test to implementation

Researchers continue to test the prototype and plan to launch the site for the Ames community in late summer or early fall. Sharma says they are working on funding to provide education and outreach for restaurants, food pantries, churches and residents interested in participating. Their goal is to add gradually other cities and regions that may benefit from the tool.

"Almost everyone has a cell phone and the technology has the potential for a much wider outreach," he said. "I don't know how successful we will be, but we're making an honest effort to tackle this problem. If we can help provide food for even one percent, we'll be happy."