THE BUILD
Built September 2-October 5, 2022
KRAKEN VS BETA
Season 6 Episode 4
Original air date January 26, 2023
FIGHT REPORT: Our strategy going into this match was to run in our vertical spinner mode (jaw down and weapon spinning upwards) because we thought we could get under the front wedge of Beta and chuck him into the air. The match started and both bots raced out of their starting squares like a pack of turtles. Clearly neither Beta nor Kraken was working properly. In the early exchange Beta was able to get under Kraken, but thankfully Cayden was quick on the weapon controls, and by moving the jaw backwards, he was able to rock us off of Beta’s wedge. We danced around each other for a little bit before Kraken was able to land a huge hit on Beta’s wedge. This bent the armor on Beta and further hindered their driving. Eventually Beta got hung up and Kraken was able to deliver some nice impacts to the back of Beta. Some of those impacts hit freed up Beta’s armor and they were able to drive much better after that. Kraken was still struggling to drive, and it started getting worse as the treads on the wheels started to load up with paint from the floor and in some cases the tread itself started to rip apart. Beta was able to take advantage and came in to deliver a monster shot. We couldn’t tell exactly what happened, but the spinner had stopped. We also noticed Beta’s hammer didn’t fare well either and was now bent at an odd angle. The jaw was still fully functional, so mid-match we decided to just become a hammer bot and swing away. The blade weighs 13 pounds, so it’s a pretty effective sledgehammer. While we were trying to hammer on Beta, he continued to hammer on us. The match ended with Beta getting behind us and landing a couple of key last second shots on the head. I didn’t see the scoring, but I have to think those last bits of control from Beta were enough to tip the scales in Beta’s favor.
DAMAGE REPORT: Well, that didn’t go to plan. The bot really struggled to move around the arena. Kraken has over 22hp of drive power and should reach around 20mph, which would make her one of the fastest bots. In the post-fight interview, I discussed the new tires we’re trying and how they didn’t work. The tread loaded up with paint from the floor and started to tear off the wheels. We also found that two of the four keys had come loose. Apparently, the Loctite reacted with the grease on the sprockets and made an ugly brown paste that never fully set. Overall, the wheel experiment was a total failure.
The wheels weren’t the only problem. In the test box after the match, 1 wheel would occasionally stop, but sometimes it worked and the other wheel would stop. We thought maybe we had a bad load in our VESC settings, so we went back to reload the firmware and recalibrate the drive. Something was wrong here, and we needed to figure it out.
The weapon on the other hand was a treat. It spun up quickly and delivered that monster shot to Beta. In the opening impact we were spinning in the upward direction, but we couldn’t get under Beta’s wedge. We raised the jaw to try to move weight onto the rear wheels to help us move around. That worked and we were able to bring the jaw down onto Beta’s armor, bending and tearing through it. We reversed the weapon and were able to take some chunks from the back of Beta when they got stuck on the floor. We were very close to disabling Beta’s hammer. The disk came down and we could see paint transfer from our weapon and a small scratch in their air-tank. We were fractions of an inch from completely destroying the air system.
That’s the point that the match started to turn. Beta landed a huge hit on Kraken’s head. That impact bent the armor that was protecting the belts for the weapon pulley and jammed the pulley. The whole head had a bend to it after the match. Beta was able to land some crucial hits as time ticked down, leaving some dings and gashes in Kraken’s armor.
KRAKEN VS LUCKY
Season 6 Episode 7
Original air date February 16, 2023
FIGHT REPORT: Oof. Do I need to write more than that, because I feel like that epitomizes that fight pretty well. For the past two days the team had been working VERY hard to correct all the issues we had in our Beta match that we thought were affecting the drive. The tires were failing, the armor was hanging up, the CG was off, and most significantly the VESC tuning for the motors was clearly wrong. We worked hard those two days, which made the match with Lucky all the more frustrating. When we got to the match our bot still wasn’t right, but we had to just send it with whatever we had. Unfortunately, when we went out to start the right front wheel refused to turn. Usually, after moving the bot a little bit the wheel would begin spinning, but this time we had nothing. Our strategy for this match was to keep the jaw down and run in 4wd vert mode, but with the right front wheel locked up we had to raise the jaw to shift the weight over the rear wheels. This was less than ideal against a bot with a stellar driver. Matt from Lucky knew exactly what he was doing and took full advantage of a Kraken machine that wasn’t at 100%. He bodied us around the arena, put us on the shelf a couple times, got us under the pulverizer, and just dominated the match. They ultimately won a unanimous judge’s decision. Hats off to Lucky on a well-deserved win, and back to the pits to dig into those drive motors for us.
DAMAGE REPORT: We had a lot of trouble with our tire treads in our first match with Beta, so for this one we tried to use bike treads, like we’ve seen other teams used in the past. It turns out bike treads aren’t well suited for 22hp drivetrains, and we absolutely shredded them. The right front wheel was locked up from the start, so it was fine, but the tread on the right rear wheel was completely gone. Neither left side wheel faired much better. The bike tread experiment was a failure, but unfortunately there wasn’t much time left that we could change before our next match 24-hours later against the very powerful Copperhead. We also sustained a surprisingly large amount of damage from Lucky in this fight. Landing on her head repeatedly bent both front wedge points inwards, chipped a tooth on the jaw sprocket, and just in general made a mess of all the top head panels.
THE GREAT VESC FIASCO: First, a HUGE THANK YOU to Brian from team Tantrum for helping us troubleshoot Kraken’s drive after the Lucky match and getting her running! We may have spent the rest of the competition with a semifunctional bot if it weren’t for his help.
So why wouldn’t this bot move reliably? Let’s dive into brushless motors and motor controllers. Brushless motors offer huge performance and weight advantages. For comparison, old Kraken had 30 pounds of brushed motors and produced about 3-4 hp. New Kraken has 20 pounds of brushless motors and produces nearly 22 hp. But brushless motors have one key drawback, ease of use. They rely on a motor controller (VESC) that turns the coils in the motor on and off at just the right time to make the motor spin. If the VESC doesn’t switch at the right speed, the performance is reduced. The VESCs require a “tune” for each specific motor. If this tune is off, the motor won’t perform optimally. If you have worked on cars, it’s like having the sparkplugs in the wrong order and not igniting at the right time.
Part of the problem is that bot builders are using this hardware/software completely wrong. It was designed for the electric skateboards. If you’re riding a skateboard, you want a smooth acceleration and constant speed. Bot builders want instant acceleration, stopping, and direction changes. Imagine riding a skateboard that accelerated, stopped, and reversed directions instantly. I see a head injury in your future.
Since these controllers are complicated AND we’re using them wrong, how is a rocket scientist like myself supposed to figure out what’s wrong with our bot? Thankfully the builder community is amazing. Brian spent several hours helping us make Kraken work. It turns out there was a bug in the specific version of firmware we were using (5.3). Brian shared the previous version of the software (5.2), and we reprogrammed all the VESCs. It made an instant difference! It was such a relief to have a bot that could go in a straight line, get there fast, spin donuts, and drive figure 8s in the small test box. It was great to finally have a bot at 100%, and we left that day full of confidence.
KRAKEN VS COPPERHEAD
Season 6 Episode 10
Future air date March 9, 2023
KRAKEN VS MAMMOTH
Season 6 Episode 15
Future air date April 27, 2023
Team Kraken 