Percussive Maintenance XL - Beetleweight Build Diary

I popped over to Norwich this weekend to compete at the inaugural MITE with PMXL

Fight 1 was against Flick!, an amazing first build that won Best Design, and rightly so, as it is a choo choo spring flipper! My works were very effective in this fight in getting under their wedgelets, which let me largely dictate the pace of the fight. The new weapon module is hitting hard, with inital misses impacting the floor with even louder bangs than previously. I managed to push them against the wall a couple of times, firing my axe while they were pinned. At one point, I managed to overturn them, but they managed to self-right. Around half-way into the fight, I opened the pit as KOs were worth more than a judges win in this format. I lost a couple of rollers at this point - these wheels had already seen a handful of events, so they were wearing down. I managed to get them in between me and the pit, and a combination of me pushing and them reversing to try to escape had them in to the pit.

It turns out that I had forgotten to add the backstop before the first fight - the top armour is used for the tech check as you have to weigh in with the heaviest config, and that integrates the backstop in. This meant that during the first fight, I sometimes had some control issues as the retracted axe was rubbing against the rear wheel.

With the backstop attached, I was up against AOB, a pneumatic flipper. We started by circling around the centre, then we went head on. They missed with his flipper, and I swung my axe in return. It turns out their top armour is 1mm polycarb, and the axe had no trouble punching through, actually getting stuck! AOB pushed me back into a wall before using its flipper to free me. I managed to get round to their back and push them against the wall, but my axe wasn’t working properly for some reason. We locked horns again and they managed to partially lift me. I managed to get around to the side again but missed my attacks, or they were weaker than usual. Another head-on engagement had AOB under me and managing to flip me over next to the OOTA zone. For some reason, the axe was struggling to self-right, until eventually it righted me. The pit got dropped in the meantime, and AOB managed to get a good pin and lift against me. We spent some time jockeying for position, until I managed to get to the side and land a full power axe hit, getting embedded again. I tried to drag them into the pit, but not quite managing it. Retracting and firing again, the axe got stuck, and this time AOB pushed me over to the pit button. The fight closed with a few more swings from me, ending the fight embedded in their top once again.

That was a very nervous fight for me, due to the self-righting issues and the control AOB exerted over me in the second half of the fight/ However, I did get the judges win.

In between rounds, I tweaked the axe settings, so retract and throttle control were upped to 50% from 30%. I suspect the slightly smaller motor and reduction were the cause of my self-righting issues, so I was hoping that just giving it more power would resolve it.

Everyone’s third fight was a 3-way melee, with my opponents being BAM!, a 2WD vert using a big brushed motor, and Gremlin Bait, a low 2WD wedge. I started the fight by going for BAM!, getting two hits in which appeared to cut all power to it. I think I managed to ever the fuse in his removable link, as it was still in the bot but there was not motion. I then went after gremlin Bait, my forks consistently getting under their wedge. I pushed them against the wall and fired a few times, severing the power light, though I initially thought I had hit their link. I managed to pin them several times, each pin accompanied with several axe hits, then the pit got dropped. Gremlin Bait got caught on the edge of the pit and I pushed them in, earning me a win.

Now into the top 8, my opponent was Boom Zoom. He was all over me in this fight, I couldn’t manage to get any hits in, and he kpt on getting round to my sides and pushing me across the arena and slamming me against the wall. He eventually got a great push and lift that sent me cleanly over the OOTA wall and out! Great job by Rob.

Overall, a great day out, well done to the MITE team for putting on a great event. I’m happy with the new weapon module, and I’m generally happy with how PMXL is running. I’v egot some AM32 ESCs on order though, I’m hoping that will help with the low speed power that would be required for self-righting. These should arrive in time for Roboshowdown at the start of May.

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Nice write-up, thanks for sharing!
I’m impressed by the polycarb impaling!

I’m planning on testing some upgrades at RoboShowdown, hopefully working out well enough to be retained for June NHRL (oh yeah, I haven’t mentioned this here! PMXL will be going to June NHRL!).

I had a productive weekend - first up was upgrading the weapon ESC to AM32. Having some self-righting issues at MITE made me finally pull the trigger on some AM32 ESCs, so I picked up some Ranglebox AM32s. I also set up an Arduino Nano to tweak the settings, to remove braking and change the kv tuning to match my weapon. Initial tests are promising!

I also made a new standard armour config, taking the weight savings from the hammersaw armour config - 4mm sides and rear (down from 8mm) and aggressively removing excess material from the front. With this config and 4 forks, PMXL is still under 3lb, so if it goes well enough at RoboShowdown, it’ll stick around.


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Back from Roboshowdown in Birmingham with another Top 8 performance from PMXL!

Roboshowdown ran a 3 fight Fight Night format with a top 8 (it was going to be top 16 but was reduced due to time constraints). The first fight was against Mow Problem, Rob Weston’s Bloodshot/Billy inspired big wheel undercutter. Because I was concerned about his blade height when inverted, I went with a split wedge design - one half anti-horizontal and one half anti-hammer saw (sans forks), the idea that if he was inverted I could use the higher wall to protect the bulkheads better. I slightly whiffed the initial box-rush, and Mow Problems was able to get up to speed for several big impacts early on, which cut the anti-hammersaw flap off and detached the anti-horizontal side from the front of the bot. His weapon started screaming (literally - check out the footage!) - his weapon gears had partially melted and weren’t meshing as well. This gave me the opportunity to assert a bit more control over the engagements rather than just impacting and flying apart. I eventually got the pit dropped and managed to get the fight close enough to the pit that he went in.

Both front wedges were badly damaged and essentially written off due to the mounting points being torn - these were given to Rob as a trophy. I also swapped out the weapon module as one of the bulkheads was cracked, and replaced a wheel that had been clipped.

Fight 2 was another horizontal in New York Slice. Slice is an interesting design in that it has an undercutter on the front but forks on the back. Because of this, I went for another split wedge, anti-horizontal and twin forks. The motor on Slice stuck out the top, and the link door was thin, so I was hoping to hit either one of those. The box-rush went a lot better this time, and the wedge held out a lot better against his undercutter. For the most part, I managed to keep engagements to the wedge, but there were a few times where he managed to clip the forks, eventually partly pulling out one of the mounting bolts causing the forks to splay out. I took several shots with the hammer where I could, but I was mostly focused on keeping the wedge pointed at the blade. Halfway through the fight, he got inverted after a big impact, which put his blade at a much more dangerous height. I eventually managed to get him turned over for a couple more hits, before the fight went to the judges, which I won.

I managed to get some fairly good shots at his top plate. There’s an impact right next to the motor, I wonder what would have happened if I had hit the shot!

The final fight night fight was against Blahaj, a great first build that was a 4WD 4-bar lifter. This time, I put on the 4 fork front and the cleaver, hoping to cut his link wire. My forks consistently got under him, but I couldn’t quite reach his link from the front. He also did a good job of either blocking me from flanking him to get to the link, or using his lifter to block blows. The fight went to the judges which I won.

Winning my 3 fights meant I was in the top 8 again! My opponent for this was Inversion, a very well-driven lifter. His forks were just a tad longer and more effective than mine, resulting in many pushes and pins from him. Unfortunately, my axe arm was too short for me to hit his link over his front wedge, and I couldn’t quite get the hit I needed on his weapon belt. There was a scare early on where he pushed me over to the OOTA zone and nearly got ne out, but I think PMXL’s awkward shape prevented it from happening. Eventually, he dropped the pit and I got pushed in. Very well done to Inversion, who ended up placing 2nd overall!

Overall, a great day out, big thanks to Tom and Sarah for putting it on, I look forward to more! And to each of my opponents, who all gave great fights. This marks the 4th event in the past 5 running tournament structures that PMXL has finished in the top 8, a fact which I’m very happy about. Its performance in all of Sunday’s fights was great as well, and I think I’m in a good place in the lead up to NHRL in June.

I’ve got a couple of changes in mind, primarily aimed at control bots. The first is slightly longer forks, with hooks (akin to Shatter’s ‘social distancing forks’) to catch robots riding up the fork and preventing them from getting too close. This should hopefully keep the main body from being engaged by a control bot’s weapon, and coupled with a longer axe arm, should let me hit them safely. The armour will also be lifted around the wheels, exposing them more, so if a lifter does get under me, I’m more likely to have at least one wheel touching the floor with thich I can try to wriggle free.

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