Backlash 2000 Construction

This is the very first version of Backlash, built in 2000 for the BotBash tournament.

After completing the designs in the computer, I started building Backlash from the ground up.

Backlash started with a base plate of 1/4" aluminum to mount everything to, this started out kind of heavy already, and I was already very concerned with staying inside the 55lb weight limit, so I milled out a few channels in the plate to lighten it a bit (with my nice new milling machine! Yippee!). I constructed the corner pieces to attach the external armor to.

Next, I started mounting the components: drive motors, Hawker Odyssey 12v battery (awesome, but probably a bit overkill on a 55lb bot), Vantec speed controller (RDFR23), and weapon power switching system (Team Delta RC switch, 12V 40A relay, and 200A solenoid).

Motors and battery are held in place with hose-clamps. Vantec was shock-mounted with spare mousepads.

Next came the options for supporting the weapon disc. Here's a picture of Backlash with some steel front weapon-support forks. I abandoned this design because the steel was both too heavy and would bend too much under stress. I replaced it all with aluminum (see below).

I started building the aluminum weapon support arms, I used some heavy gauge aluminum L-beams for the main supports, and a U-channel for the 1.4 horsepower weapon motor support. After it was constructed, I drilled out several holes to lighten the whole assembly and had the whole thing welded together. I capped the front support legs with a couple of caster wheels. I was very surprised at how much weight was saved with these holes!

The components inside Backlash were packed pretty tight to conserve space and weight, so I enclosed the whole assembly inside an aluminum box to protect the innards.

Also, note the cool drive wheels I found. These are solid, heavy duty rubber wheels that are actually made to drive conveyor belts. I tested these out extensively on asphault, and they didn't get chewed up much at all, overall, I've been pleased with these wheels.

These pictures were all taken before I extended the drive shafts. I had to extend the shaft another 5 inches on each side, because I found that when spinning the disc weapon, the gyroscopic force tended to make the robot lean to the side when turning, so to avoid flipping myself, I used the extended shafts as 'kickstands'.

I then started the chore of lightening the disc weapon. As I did with Nightmare, I started with the 1/4" thick aluminum disc, and built a hole pattern on the computer, then printed out tiled sheets of paper of the pattern, and taped them securely to the face of the disc. I put the disc on my milling/drilling machine and started cutting away.

When I was done with all the holes, I mounted the pulley to drive the weapon. I decided to try driving the weapon with a belt instead of a chain this time. It worked pretty well too!

I chose stainless steel for Backlash's teeth, just like on Nightmare. I had to mill a 1/4" wide channel through each tooth so it would fit over the aluminum disc and be attached with two bolts. This was a long and tedious operation, but definitely easier than what I had to do on Nightmare (cut a channel with a grinding disc- yuck)

That was it for Backlash! All ready for battle!

The whole time I was building Backlash, I was very concerned for the weight, and was cutting corners and holes wherever possible to lighten the robot to the 55 pound weight limit.

Imagine my happiness when I put him on the scale a couple days before the competition, and seeing those beautiful numbers: 55.0 pounds!

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