Percussive Maintenance XL - Beetleweight Build Diary

I believe normal Swiss matchups are done by grouping entrants by score, whereas we just split the field into 2 halves and randomise that way. This is because a) people can have multiple entries, so it increases the pool of potential opponents when it gets to the later rounds (e.g. preventing one person with 2 bots at 3:0 having no opponents except themselves!) and b) I’m too lazy to program it properly :stuck_out_tongue:

We have no internet access at Dojo, so we can’t use Challonge or Rampage, so I put together some Python scripts a while back to do the draws (available here, though I think I need to push some changes)

sweet! Thanks for sharing! Is it a few rounds of a round robin split in to two pools at that point? Or do opponents in the two pools still get paired by similar score?

Round 1 is just random pairings, from Round 2 we use modified Swiss, where we split the entrants into top and bottom halves based on their score (4 for a win, 3 for a jd win, 1 for a loss, 0 for a forfeit), and randomly pair in their own halves for each round.

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To finally catch up, I also went to Capital Punishment.

Similar setup to Dojo, with 4 fights with a Swiss format. For fight 1, I drew Dolos. Last time we fought, I had a battery dented when he got round to my back, so for this fight I actually took off the rear armour to expose the back wheel so if I went up his forks, my rear wheel could still steer me and I could hopefully point the shield towards his weapon. And I think this actually worked, as all the impacts I could find were on the shield. The shield itself is also 6mm rather than 4mm at Burgh 4, so it also held up much better. He did manage to OOTA me which at the time we had no idea how it happened, but watching back the footage, I can see that because my rear wheel was exposed, the rollers on it allowed my back to slide up the OOTA wall easily when he pushed me against it!

Fight 2 was against Detonator. BIG drum spinner from Milo, so the hooked forks went on. For the most part, they did their job, letting me control the fight. I got a bit brave with the axe, on several occasions sending it towards the weapon system. I kept on missing anything important though, Detonator’s design leaves a large block of air in between the weapon and the rest of the bot which my axe kept finding! He also managed to get some big pops on me, including one that removed my rear armour - I had forgotten to reinsert the bolts holding it in after removing it for Dolos! The fight went to the judges, which I won. Brilliant fight either way, I think we were both very happy with it.

Fight 3 was against newcomer Pi, with a 4WD cam lifter. I was concerned about the length of the lifters, so I removed the rear armour again for more control. I got pinned early, but firing my axe let me slowly point towards them and start pecking away. An early shot took out one of the LED strips, and later got lodged in the casing for a servo, requiring an unstick. The pit got dropped, and I was nearly pushed in, but I fired the axe a bit more and managed to get away. Eventually, I got lodged again, this time in the thick top plate, so the fight went to the judges which I won.

Finally, I went up against Icebreaker. My forks worked quite well when we went head on, but axe shots to the body didn’t do anything, as he now runs carbon fibre lids. On a few occasions, the axe went into his weapon, sending me cartwheeling. Despite the punishment, the axe seemed to continue to work. He continued to juggle me several times, but I managed to self-right from all, save the last one, which ended with me with a dead weapon and over the pit.

Fire! Of course, I lost the fight here, but what an amazing fight. After evacuating the robot and getting it open, it turns out the weapon ESC let out the magic smoke. When packing up the robot afterwards, I noticed several SMD components at the bottom of the chassis - my working theory is (because this is also an older ESC that has seen many events), the repeated shocks from Icebreaker dislodged some chips and/or the power wires, which then caused a short!

Really loved the vibes from not having a bracket here, and I think these fights were a great sendoff to PMXL V2. For now, I’m going to be focusing on the new DJ2 for beetles, while this chassis gets a well-deserved retirement! Definitely not done with PMXL of course, but the next time I get back to it, I want to redo the CAD completely (i.e. proper F360 CAD).

The last time PMXL fought was 6 months ago, and it ended with the weapon ESC going up in literal flames.

So I built a new one.

Finally moving to a fully F360 model for PMXLV3. It’s still very similar to the previous version, using the same drive and weapon motors and having a similar profile. Drive is still on Repeat Daul ESC + single ESC, the weapon ESC is now also a Repeat single ESC.

The front end has had a bit of a rejig. I’ve swapped from the 4x 5mm forks to 2x 8mm forks, and redone the profile of them.

The anti-horizontal setup has also been rethought, adding hardox to the top lip.

In terms of changes to the axe, the HDPE gear ratio is now 10:12 from 10:14 in V2.x, and the axe head has been redesigned. It now uses a 2mm impactor and brass plates to concentrate mass at the head.

This results in clean punches through 4mm HDPE now!

Taking it out for a spin tomorrow at Dojo, should be able to get some good data on the axe performance.

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