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Animatronic design challenge takes to the water

Animatronic design challenge takes to the water

Stanford mechanical engineering students demonstrate their autonomous, battery-powered waterfowl.
March 17, 2014

If it paddles like a duck, glides like a duck and moves its head, wings or tail feathers like a duck, it must be an entry in Stanford Engineering’s duck-amatronics event.

The animatronic design challenge was the final test drive of mechanical creatures that students created for Professor Mark Cutkosky’s Mechanical Systems Design class. The challenge, which drew 37 teams of four students each to Stanford’s Avery Recreation Pool on Friday, was to “create an autonomous, battery-powered animatronic waterfowl that propels itself using an authentic bio-inspired paddling motion.”

Each craft had to propel itself with “legs” and “feet,” swim at a leisurely speed of about .35 meters per second and be powered by onboard rechargeable NiMH batteries. In addition to swimming, each duckbot had to bob its head, flap its wings or wiggle its tail feathers.

ME112 students have been creating self-propelled mechanical creatures for years, said Cutkosky, the Fletcher Jones Chair in the School of Engineering. But this is the first project that required the inventions to move through water. The Unorthoducks team, Monica Vu, Susan Nitta, Josh Siegel and Kelly LaBuff, began with a wide single hull made of foam. Testing revealed that the craft went off course with the legs set far apart outside the hull. So the team trimmed the width of the hull and added a narrow hull outside each leg for stability. Vu and Nitta were especially proud of their oar-like design of the legs and feet, which exited the water with minimal drag.

At the end of the day, the El Pato Valador team, Isabel Sosa, Jose Juarez, Angel Jimenez and Juan Jimenez, won the speed category with .39 meters per second. Quack is Whack fell to 10th place, edged by Unorthoducks in ninth place at .31 meters per second. Teams scored the most points if their speed landed between .30 meters per second and .50 meters per second.

Students will present final documentation for their projects this week. Download photos of the event here.

Cutkosky said the aquatic theme was inspired by the arrival of new faculty member David Lentink, assistant professor of mechanical engineering, who is an expert on fluid dynamics of flight and swimming. After guest lectures from Lentink, the students of ME112 received their project requirements, then headed for their drawing boards and testing pools.

The teams put their entries through several design reviews and tests before Friday’s final demonstration. Many revised their craft after unsatisfactory results in early tests.

The final demonstration featured a variety of designs. A few teams went with a single-hull approach, but most favored a catamaran design.

The Duck Norris team, Brian Guymon, Daniel Espinel, Mateo Vargas and Cam Hutton, said its dual-fiberglass-hull design helped keep its craft on a straighter path. “I think we’ve done some of the least testing compared with the other teams because of the design,” Hutton said. The team also focused on keeping its design simple to make changing parts easier.

The Quack is Whack team, Monica Caravias, Colin Le, John Castello and Sid Kumar, began with a foam catamaran design, Caravias said. But after testing, the team decided on a “tank look,” foam wrapped around the entire mechanism. Caravias said the rounded front helped keep the craft on course.

With half an hour to go, Caravias said her team was leading in the speed category at .28 meters per second.