Magnets, how do they work?

**Mouldy** · 8th February 2014, 14:45

Robochallenge arena... they do all the uk champs so its there you want to use the full potential...

few tests from 540 when i first built it with magnets;

Driving verticle

Owning as a pusher... can see how it drove like it was on rails, and when other robots hit it, its like they drove into a brick wall... infact if i put the robot down on the floor... i physically couldnt push it sideways it had that much grip...also shows how the drive motors used to react to so much traction;

The next video shows how planted it made the robot when hitting into NST... doesnt budge at all... unfortunetly this is a good/bad thing... as all the force goes into making him fly off / straight into the body... which caused the armour to jam into the wheels;

The last video i found kinda wierd... it was due to the fact the magnet was so close to the drive motor i think (around 10mm away from a speed 900) or maybe it was so close to the esc...

Either way i had to ground out the magnets effect in the end as shown in the video by attaching a piece of hardox to the magnet, which in turn was held onto the removeable lid of the machine.... if i didnt do this id totally loose power to one side of the drive.

so in summary... make sure you balance out the size of your magnet to the power of your drive... if i built 540 again, id probably use a similar size magnet (50x50x20..BIG) but id go with a square wheel base with 4 off RS775 banebots on 16:1 with 75mm wheels or similar... would make for a pretty awesome pusher...

...but pushers are lame and still get owned by 720

**Flag Captured** · 8th February 2014, 17:31

How much downforce does 540 end up with in those videos? To barely move after a hit from NST is pretty incredible! It definitely looks like there's a lot of performance gain on that side of things, looking into some solutions for higher powered drive, since I think drills might be usable but end up causing a few problems...

Would there be much of a performance drop by having two smaller magnets instead of one larger one? HardWired has a removable weapon bay with a linear actuator in at the minute, and will eventually have other things like a small drum on there or what have you, so I can't really have a huge magnet on the underside of that since it'll probably wreck havoc with the weapon drives - the idea would be that I'd have a smaller magnet on each side in between the two wheels either side of the machine to keep it away from everything it'd affect as much as I could. Those wheels would most likely also have some kind of thick silver steel axle as well as bearings to help ease the load, but I'm still not sure yet.

Realistically, it's not probably going to be as solid a pusher as 540 or Stag, but it'd more be as a support to the lifting capabilities - pushing stuff around is the main aim, but if I can have significantly improved grip and stability, then that'd improve performance tenfold.

Oh, and Mouldy - that sounds like a bit of a challenge there