Congratulations to Aerospace Engineering Professor John Shaw’s team of students for their third place SPIE 2019 Bioinspiration, Biomimetics, and Bioreplication Best Student Paper Award. Aerospace Ph.D. candidate Mohammad Kazemi and undergraduate seniors Anthony Dostine and Jiadi Zhang are researching a novel use of shape memory alloys (SMAs) as artificial muscles in robotic jellyfish. SMAs are adaptive materials, a category of smart materials studied in the Adaptive Materials and Structures Laboratory, directed by Professor Shaw. SMAs are an area of intense interest due to their high energy density and their ability to transform thermal energy into mechanical work.
The biomimetic jellyfish consists of a radially-symmetric, soft rubber disk equipped with multiple flaps (similar to the tentacles of the actual sea creature) and a pre-stretched SMA spring embedded along its circumference. The SMA spring serves as the artificial muscle of the robot that, once Joule-heated above a threshold temperature buckles the jellyfish body. This buckling causes the flaps to row inwards, producing a net positive thrust and allowing the robot to swim underwater.
Aerospace senior Anthony Dostine joined the project to get more experience with structures, his aerospace engineering sub-field of interest. Within his first week of research in the summer of 2018, Dostine was able to “dive in headfirst,” becoming a full contributor to the jellyfish design, testing, and data-collection portion of the project. His main piece of advice for getting involved in research: “just ask”. Dostine urges fellow undergraduates to, “ask professors what they’re working on and how you can work with them because they’re willing to find what you can do to contribute. They realize this is a top research university and they know students want to get involved, so they’ll help you through any issues so that you can do the really interesting work.”
The jellyfish robot has many applications, all falling under the field of soft robotics, a major area of study at Shanghai Jiao Tong University (SJTU). Jiadi Zhang, a senior working on a dual mechanical-aerospace engineering degree through SJTU and U-M brought his knowledge of soft robotics and engineering design to Professor Shaw’s research project. Zhang explains how the research taught him new ways to problem-solve:
“This project is about combining what you learn in class and what you learn from nature. With our knowledge of structures, fluid mechanics, and additive manufacturing, we are able to come up with different designs and arrangements for underwater robotics fabrication. Earlier in the project, the jellyfish initially didn’t have enough thrust, so we said, let’s see why real jellyfish could move so well, but not ours. When we added flaps, that opened the door. We were able to continue the study and we made great progress.”
The award-winning paper, “Robotic jellyfish actuated with a shape memory alloy spring” was presented at the 2019 International Society for Optics and Photonics’ (SPIE) Smart Structures and Nondestructive Evaluation conference in Denver, CO.