“I was treating these rubbery materials like balloons and inflating them with air…I could make rubber fingers and legs that could bend and flex.” (Photo Credit: Dave Burbank)

Robotic Hand with a High-Tech Transmission

Cornell Research
Jun 17 · 5 min read

by Colton Poore

The world of prosthetics is evolving every day. After one of Kevin O’Brien’s good friends — a combat rescue pilot — lost her leg, she was able to receive a prosthetic and had her wings back in only a year. Even 10 years ago, that sort of recovery time was hard, if not impossible, to imagine. Yet there is still a long way to go. O’Brien, a graduate student at Cornell University and an Engineering Commercialization Fellow in the Robert Shepherd lab, Mechanical and Aerospace Engineering, is working to expand the burgeoning field of soft robotics and to witness its practical applications in the world.

Soft Robotics — Stretchy Flexible Rubbery Materials

What is soft robotics? O’Brien has a quick reply: “Soft robotics is creating robots that people actually want to interact with.” Instead of hard plastics and metals, soft robots have bodies made from stretchy, rubbery materials, like silicone and elastomers. “When I started in the lab, I was treating these rubbery materials like balloons and inflating them with air. I could easily change the shape of the rubber. I could make rubber fingers and legs that could bend and flex.”

Soft robotics, in many ways, mimics biological tissues. Our hands aren’t rigid; they’re flexible. This field of robotics tries to capture that, to make robots that are approachable in everyday life. Everywhere a person interacts with a robot — prosthetics or machinery, for instance — a soft robot could be there, inviting someone to use it.

A Better Prosthetic Hand — Comfortable, Durable, Quick

O’Brien’s work deals with three-dimensional (3-D) printing of soft robotics, an intersection that is only a few years old. “Until recently, there weren’t even printers that could print soft materials. It’s a very new field.” The soft robotic hand that O’Brien is perfecting could be used as a prosthetic — a robotic hand with human-like motion. It would have speed, strength, and degrees of freedom (the number of different ways in which the joints can move).

“Basically, I just wanted to make these prosthetic hands a little better than how they were.”

“The human hand is more than five times stronger and faster than any prosthetics out there. It has 21 degrees of freedom, which corresponds to having about 21 different motors. Commercial prosthetics only have about five. The human hand is durable, while most prosthetics might last only a few months. Basically, I just wanted to make these prosthetic hands a little better than how they were.”

Assisted by undergraduate researchers Michael Xiao and Ho-Jung Yang, O’Brien invented a small, low-cost transmission system. He could fit six of them in the palm of the robotic hand. He compares it to the transmission system in a car: In first gear, the transmission system gives a high force output, but once you accelerate, you need more speed and less force. In a car, there is one big transmission system that changes all the gears, but in a hand, there simply isn’t space.

Photo Credit: Dave Burbank

O’Brien’s small transmission systems allows more motors to be put into the hand, causing it to be both stronger and faster without adding too much bulk. O’Brien was also able to put sensors in the fingertips that allow the robot to detect how far away something is. “It can kind of see. If you throw a ball at it, or a can, it could have the reflexes to catch it.”

Through 3-D printing, O’Brien could make thousands of iterations of his designs relatively quickly. A lot of his work was centered around designing a product that would work the way he intended it to. “I would get on the computer, make a 3-D model, and print it. Ninety-five percent of the time, it didn’t work. Then I would ask myself how I could change my design to get the output that I actually wanted.” Through trial-and-error, he honed the technical aspects of his robotic hand until he obtained an outcome that functioned correctly.

The Commercialization Experience, Out of the Lab into the Real World

O’Brien was interested in more than just the technology itself. He wanted to see how his designs might function in the real world. “The engineering program has a lot of patents filed, but nothing happens with them. We have people with a lot of technical training, and it would be good to have business and entrepreneurial training as well.” As a commercialization fellow, O’Brien spent time completely immersed in a world of learning how to start a successful technology business and ways to license technology. He began to think of how an invention in a lab might actually become a real-life application.

He was also involved with the National Science Foundation’s I-Corps program. O’Brien travelled around the United States to speak with robotics companies about their needs. With this information, he would no longer be inventing new technology with no immediate use. Instead, he could improve his own technology to address some of the issues the industry was facing.

In the world of prosthetics, the most important issue was not necessarily having stronger prosthetics but instead having a prosthetic with better control and comfortable for the patient to use. Prosthetic durability was also an active area of interest. Interviews with robotics companies allowed O’Brien to refine his own designs. He realized, for example, that his transmission system in the hand needed to be made with more durable materials than he had been using.

“There is this thought with engineers that if you build it, they will come. All you have to do is build something, and you’ll be successful. But the truth is you have to spend a majority of the time talking to the humans that would potentially buy what you’re building. You have to build your technology around the customers’ needs, not the other way around.”

Above all, O’Brien learned how to build useful technology and how to sell that technology. He spoke with industry leaders and made valuable connections in robotics. It turns out that after defending his PhD thesis, he had a job offer with one of the companies to which he was introduced through the commercialization fellowship.

“I’ve always been passionate about robotics. I want to see robots out in the real world as much as possible. That makes me also interested in business and entrepreneurship and startups.” Technology can only progress meaningfully if it knows the direction in which it can grow. O’Brien, having learned something about the direction and the means to follow it, hopes to one day bring his and other technologies out of the lab and into the real world.

O’Brien officially receives his PhD degree in August 2019, and he has a position with Berkshire Grey in Boston, an industrial robotics and automation company.

Photo Credit: Dave Burbank

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