Team Toad: FrostBite 3.0

FrostBite 3.0 is the third version of Team Toad's flagship heavyweight robot. FrostBite made its first appearance at Las Vegas in November 2000, and is currently the #19 ranked heavyweight BattleBot.

(22-Jan-2002) Okay, FrostBite was in the third episode of BattleBots Season 4.0, and had a spectacular if short loss to Surgeon General.

Both robots started towards each other, but then Surgeon General turned left and ran off to the far side of the box. Julio claims he was manuvering to get to the side of FrostBite, but after 30 seconds, the crowd started booing, thinking he was merely running away. FrostBite gave chase, but wasn't quite fast enough to catch the General in the rear.

Eventually, SG turned and ran straight for FrostBite. I tried to turn to the right to meet weapon to weapon, but we met at an angle. The wicked horizontal spinner of SG caught FrostBite's thresher and right front wheel at almost exactly the same time. FrostBite's right wheel was torn off, shearing the 0.83" steel shaft of the gearmotor, while Surgeon General's wheel was separated completely from the robot and flew around the box. When SG's weapon landed, it spun for about a minute like a giant top.

The photo at the left shows two gouges left in FrostBite's outmost tooth from SG's blade.

Since FrostBite's front and rear wheels were connected by bicycle chain, when the front wheel was ripped off, the back wheel was torn off, too. Poor FrostBite sat there motionless as its thresher spun.

Without its weapon, Surgeon General tried to push FrostBite, and wound up stuck on top with its wheels spinning in the air, too. After 30 seconds, the fight was stopped while the two robots were separated. At this point, FB had a weapon but no drive, and SG could drive but had no weapon.

So Surgeon General won by a knockout. The good news is that we got to test the weapon, and it was both sturdy and destructive. Maybe next time I'll get the thresher turned into the opponent so I don't try to lead with my wheels.

(22-Nov-2001) FrostBite 1.0 had only an unpowered snowplow for a weapon. Version 2.0 had an electrically actuated control for the snowplow blade angle. For version 3.0, we wanted a more destructive weapon, so we designed a vertical spinner based on an agricultural harvesting machine. The photos at the top show our creation: the "thresher", with a 1.250 inch solid steel shaft and nine steel teeth each weighing 4.6 pounds. They mount with ANSI standard 1/4 inch keyways and are held in place by split shaft collars.

The photo to the left shows the major components of FrostBite 3.0, and the same photo to the right shows the parts labelled. The thresher is driven by a MagMotor running at 36 volts powered by 168 Nickel Metal Hydride 3000 mAhr battery cells. The batteries provide a peak current over 400 amps, and sustained loads over 300 amps for the 3 minute fight time. At 36 volts, the MagMotor puts out almost 9 horsepower. The rotating mass is 55 pounds, and the current draw at startup is approximately 220 amps. The power is transmitted from the motor to the weapon shaft using a size B V-belt, with a 2 to 1 speed reduction, giving a final weapon speed of over 2,800 rpm.

For drive motors, we use custom built wheelchair motors from National Power Chair. The front wheels are driven directly, and the back wheels ride on Team Delta pillow blocks, with bicycle chains connecting the front and back wheels. This gives us four wheel drive without the weight of four motors. The white blocks are High Density Polyethylene (HDPE), and serve to maintain tension in the two drive chains. They are not attached to the robot body, but rather float back and forth as the wheels turn.

We use a Vantec RDFR47e speed controller for both the drive motors, and an RSFR48e for the weapon motor. The batteries and Vantecs are protected from the kill saws by 0.05 inch 6-4 titanium plates bolted above the bottom floor of the robot body. The photo to the left shows a trick we picked up from Team Delta and their middleweight champion, Hazard: put double-sided sticky tape on the floor of the robot to collect and trap any dirt, shavings or pieces of metal that get inside the robot.

To mount the Vantecs and battery holders, we had to drill holes in the titanium plates. The secret to drilling titanium is to use a drill press. For accuracy, we use "Poor Man's CNC". We draw the bolt pattern on the computer, print it out on sticker paper, and then use the sticker as a template for drilling.

In preliminary testing with the thresher at full speed, FrostBite threw a piece of 2x4 over 60 feet. We are hoping for similar results with the other robots in the arena this month.

(29-Sep-2001) This is our first build report for FrostBite for fall of 2001. In order to make FrostBite a more exciting robot for the judges, we're adding a set of sharpened steel teeth made from 1 inch x 2.5 inch steel bars weighing about 4.6 pounds each. The photo at the left shows a couple of the teeth.

  

To make room in the weight budget for such a heavy new modular weapon, we've dropped from 4 motors to 2 motors. To avoid losing power as a result, we're using a pair of specially modified NPC 80522's to drive the robot. The photo at the top right shows the drive train as it was first tested today.

Of course, Team Toad is well aware of the advantages of using 4 wheels to steer in the box, so we're mounting the rear wheels on Team Delta pillow blocks with special axles originally machined by Dan Danknick for use in the original design of Ice Cube. Since we didn't use these axles for Ice Cube, we can use them now for FrostBite.

Of course 4 wheels don't help, unless they are all powered, so we're using the sprocket hubs we had made for the May competition, as well. We're using regular bicycle chains, because the sprockets are 7075 aluminum from a bicycle sypply house. To keep the chains from slipping, we made a set of floating chain tensioners from 1/2" and 1/4" HDPE sheet. We thought about bolting the tensioner to the side, but it seems to work just fine floating around.