I constructed this robot as a final project for Making Things Interactive, a course offered at Carnegie Mellon University.
Typically, most of the robotics projects I've done have been on the small scale, not exceeding a foot in their largest dimension. With the recent donation of an electric wheelchair to the CMU Robotics Club, I was intrigued by the thought of using the wheelchair motors in some sort of big project. When I brought up the idea about making a large-scale something with Mark Gross, the CMU professor who teaches Making Things Interactive, his eyes lit up like a kid on Christmas morning. His response was "Go for it!"
With his approval, I needed to actually come up with something to build with these motors. Since the wheelchair motors were very powerful, I definitely wanted to make something that I could ride on. The idea of a wheeled vehicle seemed kind of boring, so I began thinking about walking mechanisms. This was somewhat challenging since I only had two motors at my disposal and still wanted to create something capable of turning, not just moving forwards and backwards. After some frustrating prototyping attempts, I began looking at toys on the internet to get some ideas. I happened to find the Tamiya Insect. It was perfect! With this as my inspiration, I was able to create CAD models of the robot and begin construction.
During the creation of this project, I was stupid and didn't take any pictures during the actual construction process. So, to create this Instructable, I took the robot apart and took pictures of the assembly process step-by-step. So, you may notice that holes appear before I talk about drilling them, and other little discrepancies that wouldn't exist if I had done this right in the first place!
Edit 1/20/09: I discovered that, for some reason, Step 10 had the exact same text as Step 4. This discrepancy has been corrected. Step 10 now tells you how to attach the motors, rather than telling you how to machine the motor linkages again. Also, thanks to Instructables for saving a history of edits, I was simply able to find an early version with the right text and copy/paste it in!
Step 1: CAD Model
A folder of part, assembly, and drawing files for the robot can be downloaded below. You'll need SolidWorks to open the various files. There are some .pdf drawings in the folder as well, and these are also available to download in subsequent steps of this report.