The Cajun Crawler is a remarkable application of what was previously simply an esthetic design, Theo Jansen's fascinating articulated walking leg. What makes it even more remarkable is that this first-known practical application for the celebrated device was designed and built by UL Engineering students. ultoday.com shows the demonstration video and speaks with Engineering's Dr. Terrence Chambers, and Don Tamosaitis, the student who led the design & construction team.
Tell us about the Cajun Crawler.
Dr. Terrence Chambers, Associate Dean of the College of Engineering:
Actually, Don was the mastermind behind this, he built it with his own money.
The Crawler was a senior project that began as a class project for MCHE 363, the kinematics class I was teaching.
We wanted to do something interesting using the information they had learned in the junior class. This project was inspired by the artist Theo Jansen, who is both an artist and an engineer, who makes kinetic sculpture.
That was the initial assignment for their junior project, and then some of them wanted to continue it for their senior design project. Dr. Ted Kozman was the adviser for that project.
The idea was inspired by Jansen's leg mechanism. We had to do a kinematics project with Dr. Chambers the semester before, and I made a walking device out of chicken bones. When I started working on my senior project, I wanted do something that carried weight. It just kinda grew from there.
The crawler travels about 2-3 miles/hour. There were five of us working on it, there was a lot of 3D modeling of all the parts in SolidWorks, a CAD package. We tested our assembly in SolidWorks also. It's a really useful software tool, because you can make the parts and assemble them, and then check for interference, do some finite element analysis to see if it can take the stress.
The motors looked pretty small.
Yeah, they are. There are two motors on there, one for each side left & right, so it steers like a tank. They're actually 18V hand-drill motors. Our main focus at that point was getting the legs to work smoothly, and to be able to carry the biggest guy on our team, about 325 pounds. And he can ride it.
So we chose those motors because in the time allotted, you try to focus on the important things, and those motors already had batteries and switches that match them.
In the video, it seems a little unstable.
There's a little learning curve with it, just like a skateboard or a bicycle. It's really stable after you learn to use it. Guys in the video fall over because they were stopping too fast. Once you learn to stop by easing off the speed, you won't fall over.
What did it cost to build?
Between donated materials and what we bought, the materials were probably $1100-1200 bucks.
Taken from the YouTube page for the Cajun Walker:
The following video is a documentary of sorts. The video shows the Cajun Crawler. It was a project that was completed for the Fall 08 semester at the University of Louisiana. The scooter was inspired by Theo Jansen's leg mechanism. Throughout our research, we found no application where Jansen's leg mechanism was used as a weight-bearing application or vehicle. The legs are made of standard 5052 Aluminum. The joints all contain deep-groove ball bearings.