Probably not your average weekend getaway and a brief discourse on LiPos23 Oct 2016
Battle on the Parkway is a combat robotics event hosted at the Franklin Institute in Philadelphia every October, and happens to be one of two events* on the upper East Coast that supports full combat 30s, albeit with some extra restrictions due to the fact that it is hosted at a children’s museum. While most events allow the use of LiPoly battery chemistry in robots, Battle on the Parkway only allows the use of LiFe batteries due to fire hazards. LiPo batteries are readily available, light, high discharge and energy dense, which makes them an attractive battery choice in R/C and drone applications. However, LiPo batteries suffer from the fact that they are extremely volatile and can catch fire if the battery is punctured or improperly charged. LiFe utilizes a much safer chemistry, which makes it suitable for events hosted at venues like museums so the fire alarms won’t be set off by battery mishaps, especially in an application like combat robotics.
which reminds me… that I really need a better place to store and charge my own LiPo fleet so I uhm don’t burn down the second nicest residence hall on campus.
Luckily there is an army navy surplus store in the small harbor town of Port Jefferson just 10 minutes away from campus by train. I need to get myself some ammo canisters soon so I can safely and conveniently store and charge them.
My trip to Port Jeff on Saturday also happened to be the first time in my life that I walked into a place that sold guns. NY sucks :/. Need to go back soon to pick up that 100pc .50cal ammo can.
So it all began with Charles senpai asking me if I had plans to come to Franklin about two or three weeks prior to the event. Before then I had no plans to attend- it was not convenient for me to leave campus on Friday and board the LIRR and Amtrak to Philly. For a one day event, it was hard to justify spending ~$100+ just to attend the event, especially considering the fact that I had no robot compete with.
I hear you Xo. You’ll see me with a bot at Moto. I 80% promise.
But Charles was willing to swing by the city before departing for Franklin to pick me and Cassandra up, making a Franklin weekend trip much more realistic. Love you <3
However that meant that I had to meet up with mikuvan at West Harlem at 6:30AM… which presented a very real challenge to me considering the fact that I am very much not a morning person. The ever so veritably reliable MTA runs very infrequently during the graveyard shift, which made the trek from the eastern reaches of Queens to West Harlem all the more difficult. I recall waking up at 3:30AM to shower before heading out, but a quick glance at bustime indicated that the Q65 bus to Jamaica wouldn’t come anytime soon.
Which gave me an excuse to use my referral code and call an Uber to Jamaica.
I was immediately reminded of just how sketchy the stations in the Jamaica area can be during the ass o’ clock hours. After avoiding the gaze of several panhandlers who approached me, I stepped onto the F train with some equally sketchy passengers. Perhaps Bethesda could take very useful notes for Dishonored 2 worldbuilding…
some two hours later, I reached my destination at the CUNY Tower where I met with Cassandra. My timing couldn’t have been better, as not even two minutes passed when I saw mikuvan reversing down the one way street to meet us. Oh Charles, I honestly did not expect any less. The path of least resistance sometimes require a few rules to be bent, kashira.
Charles brought Jamison along for the ride, who in a last minute decision made a LiFe battery for MegatRON/notsawblaze so it could compete at Franklin. picture credits to Cassandra
We later converted this battery to an XT60 output connector so it can reliably interface with a charger.
Cassandra brought a 6 pack of pumpkin ale, ale which I could not resist the urge to pregame during the ride down as I witnessed the fiery amber sunrise pierce the dark sky with its periwinkle tendrils in what must have been the first time.
I must admit I did get slightly buzzed after I finished the bottle.
Parking was a bit awkward to find because the parking lot was full by the time we rolled in, but we managed to park in the corner with about 3mm of clearance between mikuvan’s roof rack and the ceiling.
Fights started around an hour after we arrived, and I assigned myself to the duty of being Jamison’s pit bro. Jamison was running one robot in each weight class, so I helped him make repairs and recharge batteries when he was competing. Due to the extremely short time between fights, it’s extremely difficult for one person to compete and take care of behind the scenes stuff as well without forfeiting because you did ran out of time, but that didn’t happen to us ^.^
Shortly before Franklin I got myself a nifty Nebo tool, which I saw Jamison use during last Motorama. It’s a ratcheting socket tool that comes with different screwdriver attachments. Came in very very handy for servicing MegatRON.
Here is MegatRON in all its pretty glory-
It uses 2 Axii motors mated to P60s for drive, and the same motor to power the weapon. Unlike the last MegatRON at Moto, this version contains all its motors except the arm actuation motor inside the chassis bulkheads instead of having the weapon motor mounted on the arm. This is accomplished via a “live dead shaft”, which is essentially a live shaft that rotates over a dead shaft that the arm is connected to.
In addition to MegatRON, Jamison also ran Silent Spring and DDT, a beetle and an antweight respectively. Both robots made it very far into the bracket, with Silent Spring winning the Beetleweight championship title. Silent Spring, picture credits to Cassandra DDT, picture credits to Cassandra
picture credits to Cassandra
Megatron is packaged so efficiently and neatly o.o
Charles brought Not Overhaul to Franklin, which is essentially a scaled down version of actual Overhaul that competed at Battlebots last season.
Like MegatRON, it also uses 2 Axii-P60 gearbox combo for drive. It features custom Urethane molded wheels to divert arena grime away from critical drivetrain moving parts, a design decision made by Charles so that #setscrewghazi never happens to him again ;). Charles goes into more detail on this at his blog here.
Do you have a minute to learn about our lord and savior, Markforged-jesus?
If you take a look back at the photo of Megatron’s guts, you’ll notice that the chassis cavity is formed by four black bulkheads. These bulkheads aren’t aluminum or steel, but rather a 3D printed plastic developed by Markforged called Onyx. It’s a plastic alloy of Nylon and Carbon fiber, which the Markforged 3D printer can lay down in continuous strands, rather than in chopped up bits and pieces like how all the other 3D printers print Nylon or CF infused -insert plastic here-. The successful use of Onyx as the chassis material is a testament to its astounding mechanical properties- well, all the way until it failed under extreme circumstances.
Which brings me to this robot, Big Ripto. A very very nasty single tooth disc (STD) bot indeed.
This is the bot that chewed its way to the 30lb full combat championship title, leaving nothing but broken parts and shattered dreams in its wake.
MegatRON eventually faced off against Big Ripto after defeating Not Overhaul, which ended in MegatRON’s front plow shearing from the Onyx bulkheads when MegatRON’s underside made contact with the STD and into the arena ceiling .
Here is MegatRON post-match.
The saw on MegatRON is a HSS slitting saw, so it fractured as expected when it made contact with Big Ripto. While steel is usually rather ductile, HSS is hardened to a point where it acts like a brittle material.
The electronics were not damaged by the impacts so MegatRON lived on to fight again against Overhaul, which was also crippled in an earlier match against Duck Yeah, another STD style robot.
The steel plow (the quarter inch AR500 escaped mostly undamaged) was bent and ground back and reattached with Harambe tape and whatever screw threads remaining that were not completely sheared off. notoverhaul won the match, pitting it against Big Ripto. At that point, Big Ripto did enough damage to the arena that the EOs decided that it could not contain another match with Big Ripto, so Charles gave Big Ripto the match as it was very unlikely notoverhaul would have won at that state.
Seeing as how the fights towards the end had to be paused for nontrivial amounts of time to hammer the door and various lexan panels back into place, I totally agree with their decision. The ceiling impact sustained in Big Ripto v. MegatRON packed enough energy to partly pop out and bend a lexan panel. At least we’re better than India, right?
After a very grueling twelve hours, the event finally concluded with the last antweight match. Spencer and Luke left early and invited us to a local pizza place, but in the best interests of the group (we were very tired, hungry and still had a long drive home) we stopped at a Tony Luke’s, a philly cheesesteak place somewhere in New Jersey for dinner.
PC to Cassandra
None of us ordered any toppings on our cheesesteaks because the menu inside the store did not list that option at all. So we all got very mediocre cheesesteaks that tasted exactly like how I expected roast beef, cheese, and bread to taste when you put them together. It was only until we saw a menu poster outside the store when we realize we all fucked up**. :( next time.
I managed to get home around 2AM after we arrived back in Uptown Manhattan at midnight, probably making this the longest day of my life.
So naturally I spent the majority of the following Sunday catching up on sleep.
*To my knowledge, anyway.
** Jamison got cheez whiz as the cheese option because that was the default, and cashier mistook his cheese fries for regular fries so we feel extra bad for him. On the bright side, maybe they would have used cheez whiz on his cheese fries too?