BattleBots

Since I've had a good amount of free time so far this summer, I've spent some of it on my latest fancy: combat robots! I remember watching BattleBots on TV many years ago and thought it was totally awesome. Ever since participating in 2.007 at MIT, I've wanted to build one of my own. I also have a friend who has built and competed with several combat robots, so that helps too. So far I've come up with two designs, both of which utilize the ever-destructive spinning weapon on top. The first is a 30 pound robot that I call Eli Wrath (a play on my name and Eli Roth, as inspired by a silly robot I made last summer in about 1 hour when I was bored).  Here are some renderings of the fully functional Solidworks model.

The dimensions are about 14"x12"x4", and based on the Solidworks estimate it will need some more weight reduction to be under 30lbs. I also priced out the parts to at least $500 without waterjetting. However, I still would probably want to replace the brushless hobby motors with brushed motors for more torque. Factoring this with the amount of work it takes to machine steel, I thought I would try designing a 3 pound miniature version. Thus, I present EliBot.

The dimensions for this one are about 7"x7"x3.5". As you can see, the frame is entirely waterjet out of 3/16" aluminum plate. I had a lot of trouble with the weight, but luckily I was able to cut out some of the frame and remove the motors from the two backwheels to come out to 2.9lbs without the electronics. Those should be pretty light, but hopefully the Solidworks estimate isn't on the low end or I might have to come up with some "creative" solutions to keep EliBot under 3lbs. With a T-slotted frame, assembly should be relatively painless, and it should cost around $300 for all the parts I need, including the waterjetting. Birthday present, anyone?

Eli-Kart and Motor

After a busy spring semester, I'm finally done! As I mentioned in my last post, I was an assistant for the electric vehicle section of 2.007. To go along with this, I worked on Eli-Kart for my undergraduate thesis. Now that the semester is over, I can tell you all about it. But first, a video!

Eli-Kart's design has remained largely the same. See how similar they look? However, I also designed and built a large custom brushless motor that could be used to replace the hobby aircraft motor seem in the original design. I used FEA and CAD to help with the design. Here's an exploded rendering of the motor, along with the results of my finite element analysis on the motor using FEMM.

With the hobby motor, Eli-Kart tops out at about 20mph and has good acceleration (depending on the load). The motor overheats if you beast it too much though, but its good for cruising. If you're interested in learning more about the process, I created an Instructable that details the design of both the go-kart and motor.