Talking Shop with Assistant Professor Sangbae Kim


Professor Sangbae Kim Robotic Cat

Images courtesy of Sangbae Kim.


How does biology inform your research?

Our core motivation is to discover the design principles of biological systems to implement in robotic design. Simply mimicking their mechanical features may not be an effective method, because, unlike in nature where every feature needs to function alongside other physiological requirements, such as growth, reproduction, and digestion, engineers don’t need to consider these things. After learning more about biology through literature and discussions with biologists, I realized it takes much deeper reasoning to extract principles from such complex systems with intermingled design requirements.

Our research is centered around the idea of testing our hypotheses about biological design to ultimately solve our engineering problems. Because there are so many constraints and variables in nature, we decided to try testing in an engineering domain. Interestingly, sometimes the principles inspired from biological study is verified in robotics systems but not applicable to biological systems, due to that complexity.


How do you apply this information to your work in robotics?

We are trying to develop design and control principles to enhance the mobility of robots through these interdisciplinary research activities. There have been tremendous advances in robotic intelligence systems, but the mobility of robots is still very limited. For them to be useful in hazardous environments, or even in our living spaces, mobility is a critical factor. That, combined with the interest in how animals work, was the impetus for the hyperdynamic robotics we’re working on now.


Explain your current project, a robotic cheetah.

The fastest land animals, reaching speeds of about 70mph, cheetahs are fascinating. We are trying to extract design principles from these extraordinary creatures to develop dynamic mobile robots.

We have very little data for cheetahs, but there are two behaviors we found fascinating. One is that we noticed that cheetahs use their backs so much more than other animals, for example, greyhounds. We hypothesize that it helps them run faster. Their tail movements are very interesting too. When cheetahs change direction while they’re running, their tails are whipped in the opposite direction. These are both very interesting phenomena but extremely difficult to analyze. We are excited to implement our hypothesized design principles in our robotic systems and evaluate them.

There are many unexplored principles in biological design. It’s thrilling to discover them since they advance our engineering system building blocks. But an even more vital benefit of bio-inspiration is its ability to introduce a new perspective. We created airplanes by implementing the principles from birds, but we may never have even thought about flying if there were not flying animals.meche logo


Sangbae Kim joined the MIT Department of Mechanical Engineering in May 2009. He received a PhD from Stanford University, followed by a post-doctoral appointment at Harvard University’s Micro Robotics Lab. His research focuses on bio-inspired robotics and adhesion, and his work has been featured in several media outlets, including The Discovery Channel, Forbes Magazine, and National Geographic. In 2006, his Stickybot creation was selected as one of Time magazine’s best inventions of the year.