My second Antweight Robot: "mV"

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JeffSergeant
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My second Antweight Robot: "mV"

Post by JeffSergeant »

Principle behind this one is to start with CAD/3D, the last one started with whatever I had laying around. So I did! and it looks remarkably like the plan. Mapped it out in Blender 3D; 'Unwrapped' the chassis mesh and printed it on a piece of paper; transferred that onto aluminium and cut it out.
Image

For control; I hacked three 'Tower Pro' 9g Micro Servos (SG90) into two ESCs (I think I melted one with over-enthusiastic soldering). Removing the potentiometers and soldering resistors in their place. Both servos had a different 'centre point' on the pot (surely it's harder to make them inconsistent than it would be to make them identical?) one was 1:0.666 the other 1:0.75 This resistor combination calculator was invaluable.

Image


Screwed to a testing chassis with a testing RX, it drives really well compared to my last robot, (Youtube).
will definitely be converting the other one's drive system to these controllers ASAP

The basic construction is almost flea-weight compatible, main chassis, motors, BEC and receiver come in under 75g, but is slightly too wide.

With 75g to play with, I have added a BLDC motor with an emax bullet ESC; and strapped a blade to it with a couple of screws into the shaft supported by cable ties. Tried to cut a thread on the motor shaft but it's made of a harder metal than my Aldi Tap & Die set (i.e. something harder than cheese) so no joy.

Currently does more harm to itself than anything else; mostly in the form of rattling screws loose until it breaks something.. but it's entertaining to watch; and I made a robot with a spinning weapon! How cool is that?
In 3 testing rounds, it lost to: A Scrap of Metal; The wooden Testing Box, an LED torch, and Itself (Youtube).

Need to upgrade the blade to something less bendy, and fine something slightly more robust than masking tape to hold it's guts in, then apply liberal amounts of epoxy to the loose bits.. then I'm done for this iteration!
Derek Dudge
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Joined: Thu Dec 07, 2017 9:32 pm

Re: My second Antweight Robot: "mV"

Post by Derek Dudge »

Indeed it is cool, and the test video made me laugh. You say it's your 2nd ant but are you already a robot builder for other weights or something? You seem to know your stuff about the components.
My robots:

Third Law (antweight) - push/ram bot
Manticore (antweight) - hammer bot
Paulmchurd
Posts: 227
Joined: Sun Dec 10, 2017 4:39 pm

Re: My second Antweight Robot: "mV"

Post by Paulmchurd »

How easy is it to bend the aluminium and what did you use to do it?
JeffSergeant
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Re: My second Antweight Robot: "mV"

Post by JeffSergeant »

Paulmchurd wrote: Thu Feb 01, 2018 7:29 am How easy is it to bend the aluminium and what did you use to do it?
It's only 0.8mm, it bends with a stern look! I bent 3 sides with a bench vice and the last with a pair or pliers.
Derek Dudge wrote: Thu Feb 01, 2018 6:03 am are you already a robot builder for other weights or something? You seem to know your stuff
My job is seeming to know what I'm talking about! It's technically my 3rd if you include my janky robot arm!
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GeorgeR
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Re: My second Antweight Robot: "mV"

Post by GeorgeR »

JeffSergeant wrote: Thu Feb 01, 2018 8:47 am It's only 0.8mm, it bends with a stern look!
Is it wrong to hope one of my spinners gets drawn against this?

But on a more helpful note, the properties of aluminium varies dramatically depending on the alloy. The most common aluminium sheet (and I guess what you've got here) is the 1050h14 grade, which is fairly low strength and generally not recommended for robots. A better bet would be 6082t6, which is 3 times stronger.
Team Zero - AWS 58 Champion!
Zero - rambot - - Axiom - axebot - - Valkyrie - drum spinner
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RBMK - quad spinner gyro walker - - Duality - dual spinner gyro walker
JeffSergeant
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Re: My second Antweight Robot: "mV"

Post by JeffSergeant »

Is it wrong to hope one of my spinners gets drawn against this?
Bring it on! I'm totally open to the prospect of having a mangled lump of ex-robot to commemorate my first foray into Antweights; I was only supposed to be going along to watch, I slipped and accidentally made a couple of robots, just passing the tech checks will be a major achievement!

This Aluminium had the benefit of being £8 for a sheet that's lasted me two robots and counting; and I have all the tools I need to work with it! If I have fun this weekend I'll work out a proper plan for the next bot; probably polycarbonate over metal.

The other end is a lot fightier though, I've found a suitable piece of steel to replace the aluminium blade, it certainly looks the part.
JeffSergeant
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Re: My second Antweight Robot: "mV"

Post by JeffSergeant »

Survived Antfreeze 5, did so much better than expected, got lots of time in the arena.

First round it wouldn't start, until I whacked the throttle to 100% and it did an awesome gyro backflip, still drove inverted and put up a good fight.

Second fight, spinner was totally dead, I think I started it up with the wrong model on the transmitter, which the ESC didn't like; probably for the best as it won by pushing and no unexpected backflips.

Third fight, Spinner worked! The opponent kept getting within it's radius so it couldn't start up, but when I got a bit of space and ramped it up it did exactly what it was supposed to do.

Fourth fight, controls were a bit dodgy by now, again, spinner failed to start, I spent so much time trying to get it working I forgot to pay attention to the opponent and got pitted. The spinner started up when it was teetering on the edge of the pit, and bounced me back out again, but apparently that doesn't count!

Gladiator: Survived for a bit; got inverted, then got stuck on a pile of robots, then Tlactotlyllltosoldlldsldl put me out of my misery into the pit. Took a huge whack from a vertical spinner in the process bending the blade 45 degrees, and bending the brushless motor; can't wait to see the video of that one because I have no real idea what was going on!

Lessons: Spinner is awesome when it works, but need to get it working more than 25% of the time! Start with balancing the blade, then check the ESC is rated properly. hopefully that will help the motor spin more consistently, if not work out why not!
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