Sink or swim

On a Friday in early December, teams of students from ME 102B displayed their inventions, products and novel devices along the hallway on the ground floor of Etcheverry Hall. The day marked the end of Professor Homayoon Kazerooni’s mechatronics design course for mechanical engineering seniors. The class, a much-anticipated part of the ME undergraduate experience, lets students take everything they have learned during their college career and put it into one capstone project.

In years past, ME 102B students began the class with an open-ended syllabus. “We used to let students work on anything and everything and come up with whatever they wanted, as long as it contained mechatronics and creativity,” says Yoon Jung Jeong, one of the course’s graduate student instructors. This semester was a little different.

Students were given the option of designing an amphibious vehicle built from parameters supplied by DARPA, the Defense Advanced Research Projects Agency.  The goal of the government agency’s sponsorship of this exercise was not so much for the students to build the best vehicle for land and water, but to test a new set of modeling tools, in the hope of saving time and money when it awards contracts to build new equipment.

“Their modeling software is so new that they are trying to get feedback,” says Kyle Edelberg, a graduate student in Professor Karl Hedrick’s vehicle dynamics lab, and one of the liaisons between DARPA and the student teams in ME 102B. Berkeley was one of the first universities to be involved in the testing, along with engineers from Vanderbilt and MIT.

By noon on demo day, the demonstrations began pouring onto the trellis-covered plaza outside. Some of the students continued to tinker, making last-minute adjustments to such varied creations as an electric go-kart, a robotic bottle opener and exoskeleton devices. The amphibious vehicle teams gathered on the adjacent sand volleyball court behind Soda Hall.

Thanks to the winter rains, the court had turned bog-like, with soft spots and giant puddles. On one side of the court, graduate instructors placed a ramp leading to a wading pool filled with water—the perfect proving ground for the new vehicles’ capabilities.

The amphibious vehicles, each about the size of a large suitcase, presented a mechatronics design challenge. Teams spent months testing different methods of powering their vehicles and getting them to transform from a land vehicle to a water craft. One team even set out to build a hovercraft, but then shifted quickly back to a more traditional vehicle design. In the end, the vehicles that performed the best were the simplest, allowing for multiple iterations over the semester.

Before long, the crowd stood in a knot around the small pool, cheering and providing out-loud critiques—mostly about the driver’s ability to handle the remote control. There were collective sounds of approval when the vehicles made it near the water hazard, which was their final destination. Towards the conclusion of the demo, one vehicle, called the “cooler” because it looked like a rolling purveyor of cold beverages, sped up the ramp and splashed hard into the pool, soaking many in the audience. There were more cheers.

Despite the playfulness on the volleyball-court-turned-testing-course, there was an undercurrent of seriousness, and not only because of the implications for national security.

“This class helped me to solidify that I’m interested in designing and building things,” says Spencer Poff, who will be graduating in May and is considering a career in product development. Standing over the “cooler,” back in the mechatronics lab, with its lid off and inner workings exposed, he says, “In the beginning all you have are the design constraints on paper—and then you take those and use them to build something.”