$10 Construction
There wasn't much in the way of designing this robot. 2003 was my first year competing in the ECRG, and I wasn't really sure what to expect in a 6.6 pound sumo. I found an r/c car for sale at a clearance store, upon noticing that it had two drive motors, I bought it immediately. I thought it was just what I was looking for, just replace the wheels with much smaller ones to give it more torque. After stipping it down, I came up with a design that gave it decent traction, and excellent handling characteristics. A tall, wide shape that was very short. This ensured that most of the robot's weight was on the drive wheels, and made it turn very quickly.
The Event
Beast of Burden put in a decent showing, winning two of its matches while losing one. Its ability to turn quickly was a definite advantage, despite the lack of power in its drivetrain. Although the robot good reach a decent speed, even with smaller wheels it had little torque. This is what cost me my last match, as I could get underneath my opponent right from the beginning of the match, but it was a struggle to push it out. I ended up driving myself off of the platform in two of the rounds.
Lessons Learned
Basically, speed means nothing if you don't have the torque to back it up. The rebuild for ECRG 2004
And The Designing Begins...
About 3 or 4 months went into designing the robot on AutoCAD, with most of the time devoted to the drivetrain. Actually, all of the time went into the drivetrain, construction on the weapon only started two days before the event. The drivetrain was much improved over the previous year, with more than enough torque to spin the grippy foam wheels, and with only a slight decrease in speed. The only explanation for this was that the drivetrain was overloaded last year, which I already knew. The drive modules consisted of 2" x 2" aluminum square tubing, which housed the wheels and the gear train.
Made the trip to Toronto once again, this time with my good friend Tom, who brought one hell of a mean little machine called Tiny Thrasher. Met up with some other competitors and saw their creations. Some interesting designs, although the classic wedge shape prevailed. The weapon was not done in time, but with Tom's help, we managed to attach a ramming lance to the lifter assembly. This aided the robot, although Beast of Burden was plagued with problems with the gears in the gear train. This problem was fixed on Saturday night, although it was a bit too late. Beast of Burden finished with a record of 2 wins and 2 losses, with one win coming in the form of a BYE, and one loss with someone else driving the robot (we had to go check into the hotel, and missed our last matches).
Publicity? The Wonders of Television
Tom and I received some publicity in the way of an interview by a university newspaper of some sort, as well as a brief camera appearance by Global. I was a little too pre-occupied to care at the time. However, we did get a LIVE interview by CBC Newsworld, which ended up being 5 minutes in length. Not too bad...
Plans for Next Year
Not much will change in the drivetrain, as I was very pleased with it. The weapon will be finished this time, not quite how I originally designed it, but it should still be effective. You'll just have to see next year! (Here's a sneak peek)
The jaws were made out of polycarbonate plastic (bulletproof lexan), and were shaped to resemble a beetle or ant's jaws. Springs were used to open the jaws while a power screwdriver motor with steel cables was used to close them. The only part of the weapon that wasn't finished in time was the attachment between the jaw assembly and the lifter portion, which consisted of another power screwdriver motor with a 2:1 gear reduction in a lexan gearbox. Installed a last minute weapon in the form of two lexan wedges, each hinged on the front of the drive assemblies
ECRG 2004, here we come
The rebuild for ECRG 2005
Going Back To Basics
The image you see above is what I was going to bring to the ECRG in 2005...however, the gear problems that plagued me in the 2004 event returned, and I had to ditch the 4 wheel drive setup that I liked so much. As a result, I went back to what worked for me back in 2003. This was a 2 wheel drive setup with plenty of speed and a fast turning radius.
I used the same motors as the two previous years, but I made my own gearboxes for them, as well as over-volting them to 12v. I decided that it was time to go big or go home. I fashioned a lifter assembly consisting of a 6v power wheels jeep motor (also running at 12v) with a sharpened wedge blade attached. This blade was made of tool steel and was tested as 60 Rockwell C. For those who are not familiar with this hardness scale, let me just tell you that you cannot cut or drill through this metal without annealing it first. To avoid this, I used a mill to make a clamp-type holder for the blade, which worked beautifully.
The Event and Its Misinformation
Due to some strange and last minute rule changes, lifters were not allowed. In previous years, you could lift and flip your opponent as long as there was no intent to damage them. This rule change was so sudden that they had to re-do a couple of the first round matches just to comply. The Beast Of Burden now had to leave that blade stationary, pretty much wasting the big lifter motor that I had attached.
After about 3/4 of the first matches were filled with no-shows, the organizers made a revised list of matches with those who were actually attending. The Beast of Burden went undefeated (3 and 0) until the semi finals. There were then three robots that had to fight to determine who came in first second and third. How it worked was that everyone in the semi's faced each other; whoever ended up with 2 wins was the champion, 1 win was second, and no wins was third. First up I faced a robot called Space Junk. I was very familiar with this opponent and I knew the torque and traction it had. After a tough couple of rounds I smoked one of my drive motors. With no spares I had to face my good friend Tom (Tiny Thrasher) immediately after. I gave it my best shot, but going in circles isn't going to win a match.
Tiny Thrasher won both of its semi final matches (against Space Junk and I) and won first place in the R/C Sumo class. Space Junk came in second, while I came in third with Beast of Burden. Below is a list of five things to sum up this year's event:
5. Beer.
The rebuild for ECRG 2006
4. The ECRG is an awesome event.
3. I finally placed in the ECRG (and went down smoking at least!)
2. Tom came in first place!
1. The big name in the R/C Sumo event (Biohazard) went down hard, 4th place.
The rebuild for ECRG 2008
Even though the previous version was highly successful I was a little bored of it and there were no room for changes. For this design I went back to the basic drivetrain of 2004...two drive motors with a custom geartrain to four wheels. I crammed the biggest motors I could fit into the bot, and it has unbelievable power for a robot this size. Check out my YouTube account for videos of some of the matches
2009/2010
Four Mabuchi 550 motors, custom spur gearing, and custom moulded urethane wheels makes the newest Beast of Burden a mean competitor in the sumo ring!
