Toobrichard (Hobby Weight 12lb)
Toobrichard is my hobby weight (12lb) combat robot. The name is barely funny if you know the long rambling joke and entirely unfunny to explain, so I will not. Toobrichard was made possible by a sponsorship from the Bot Hockey League designed to allow more people to get into the sport. I took the chance to build a robot I had already been envisioning.
The goal was simple: build a hobby weight robot for under $300. Simple, at least, in theory. Combat robots typically follow the cost estimate of $100 per pound, so I was trying to build a robot for ¼ of the typical price. As an added challenge, I wanted to try to make Toobrichard simple to build and easily scalable, should I want to sell a kit of the robot. It needed to be able to be built economically with the machines I had access to. Thankfully, I have access to a good number of tools.
Manufacturing!
(The fun part)
I manufactured my prototype using scrap 16Ga 4”x2” steel tubing on a Bend-Tech Dragon A400 plasma tube cutter. I was working on getting the machine running and the chassis was complex enough to test multiple different features of the machine. It also gave me a chance to test the software’s ability to import a STEP file. As a plus, I got some very cool videos.
After I got the prototype functioning, I unfortunately did not get to keep playing with the Dragon. The final robot is made of 0.25” tubing of the same size. Due to the budget constraints of the project, I could not get stock long enough for the fixturing in the machine. Instead, I went to my local metal supply company and combed through their remnant racks. I got very lucky to find tubing that was almost exactly the correct size. When cut to length on the bandsaw, it would be perfect.
With some extra manpower to speed things up, I cut the chassis to length on the bandsaw the went to the mill to add the slots for the fork mounts and threaded holes for wedge mounting. Using an angle grinder and a Dremel, I cut out the top bottom slots for the wheel wells. Then the chassis went back to the mill to be cleaned up before welding.
Both chassis were primarily welded together with a MiG torch. The chassis received two endcaps and fork mounts welded on. Then, with the shop closing the night before I needed to leave, I quickly made top plates out of scrap steel using an iron worker.
COMPETING (The funner part)
Toobrichard competed at Orange County Maker Faire in SCAR’s Big Bot Event. It also competed in the hockey bot tournament the same day. For a first time running the robot, it did great.
Certainly a Robot
Success! I built a robot for only $300! And All it took was thousands of dollars worth of equipment. In all seriousness, I had planned to use mostly those thousands of dollars worth of equipment, but most of the days I was working the shop was closed, so I actually ended up mostly just using hand tools. A Toobrichard can be built with a drill, Dremel/angle grinder, and a welding torch. It’s a bit easier with a drill press, but it would still be doable without it. Using a 3D printer, even the welding could probably be avoided entirely.
Future Upgrades
I have some big plans for this robot. It has a lot of potential but definitely needs work. The addition is a wedge for the front of the tube. This will serve as armor, but also keep the robot from tipping too far forward. It will also push the center of mass further forward. The wedge also allows me to add magnets for downforce to Toobrichard without it becoming stuck to the ground.
I also plan to add a wheelie bar to the back of Toobrichard to keep it from tipping back when it starts moving.
