Roko.ca

Sometime in the mid to late 90s, I got the idea to build a quadrupedal walking robot. Ideas bounced around my head constantly since then, but school and work got in the way of “free time”. Over the years I gained more knowledge and experience in electronics and robotics design, and constantly refined the ideas I had in my head. In mid-October 08, with the local diving season comming to the time of year where it no longer takes up most of my free time, I finally began to get concrete design work done on the robot. The picture below is what I came up with.

An admittedly ambitious project, this Quadruped is to be named Bert and/or Spyder, I haven’t really decided yet. It will be powered by 3 PortEscap gear motors per leg (a sum total of 12), due to a lucky surplus find a couple of years back, at BG Micro. Each joint will have bearings for smoothness (another surplus find, care of the the Electronics Goldmine). The frame will be rough cut from from Aluminum by the Big Blue Saw. Although it’ll add a bit of cost, it will save me an imense ammount of time making some intricate parts and fancy shapes, so I decided it would be worth it. The rest of the machining to be completed on my Dad’s Sherline mill and lathe.

The brains will be a Gumstix computer I picked up a while back and have been playing with, and eventually I plan on creating a head to go in the center of the robot, however I haven’t quite decided how I want to go about this. The entire robot will be powered by some LiPo batteries, which hopefully should provide a good life time.

After a couple of months of design work, I finally sent the files off to have the core, and one leg water jet cut. I only ordered one leg to start with in order to make sure everything works out properly before committing to building the other four legs. Today I got the water jet cut parts back, and they look nice! All the parts came connected as one big piece, so some dremel work was required to seperate them without damaging the parts, and I’ll have to take care in filing the connecting bits flush to the part.


Another issue with water jet cutting is the kerf diameter, or diameter of the waterjet stream, in this case approximatley 1mm, so some corners that I had cut to that diameter will need to be filed into square points, but that’s no big deal.

Next up, I’ll have to do the boring and drilling of various holes that will fit bearings, shafts, screw threads, screw counter-bores, and various pins for the various parts of the robot. This will probably take a while to do since I’ll have to take it easy to make sure everything lines up correctly.


To the left you can see some of the parts that will make up one leg of the robot. I’m still waiting on some small parts such as teflon washers to use in the joints, but that should be arriving any day now. You can see my H-Bridge in the mix, I’ll need 6 of those dual H-Bridge boards on the final robot.


All in all an exciting build!