Bit of advice on my drumbot please

**calumco** · 20th September 2011, 10:22

right, hoping to start making a new one this friday, ordered some 20mm nylon 6 for the 2 bulk heads that will support the drum and the drill motors, theres gonna be a 3mm ali or mabye even 2mm ti baseplate and the rest is hardox with the exception of the lid

but i need some advice as to whether i go 2 or 4 wheel drive off a pair of drill motors some pics are below........

[attachment=1:39vw2ait]BILD0001.JPG[/attachment:39vw2ait]

[attachment=0:39vw2ait]BILD0002.JPG[/attachment:39vw2ait]

not fully settled on a design yet and the insides would be set out differentally but i'd use the 75mm wheels instead thou to save on the weight as wheels that big aren't really needed but im really stuck as to what set up im having, the benifits of 4 wheel drive were purley due to the drum being 3.7 kg i was worried about it being front heavy and not driving properly so with 2 wheels either side of the drum it would get rid of this problem and drive better, but then of course then theres all the extra weight from extra wheels and mountings etc and the robot slowly starts to get less compact as it'd have to be made wider to house the wheels and belts so i'd have to skimp on armour. or with the 2 wheels i'd use that size of wheel but i've tried making the robot to have as much weight as possible over the wheels and i've also put them as close to the drum as possible. Althought 4 wheel drive would look better visually, part of me just wants to keep everything simple and 2 wheel drive and see what happens,

then of course theres the problem of it not being invertible, but i think i could live with this because once its upside down anyway the drum isnt effective spining downwards, i could use those massive 150mm wheels again but i don't fancy it cause that take away too much power from the motors and pushing power is very low, but any ideas anyone?

**Ellis** · 20th September 2011, 11:27

I'd personally try to setup 4 wheel drive. No use having a stonking weapon if you can move it near the enemy effectively! And surely 2 belts and 4 pulleys, with bearings and mounts, isn't going to hugely affect your weight? That weight could be made back quite comfortably by cutting holes in bulkheads and smaller batteries?

**rallikas** · 20th September 2011, 14:12

Hmm... the drum setup you are using isnt going to work! That kind of setup doesnt work, as the COG on the drum moves up and down (or something like that

)as it spins, and there are going to be some very bad vibrations.

**calumco** · 20th September 2011, 14:25

heyy yeah i forgot to say i already new this, the 2 bars were a rush job to get my old drumbot working and they were a very bad idea. im grinding those off later on in the build and getting 2 ring teeth made with 2 teeth on each. not fully decided on that thou yet

**Mouldy** · 20th September 2011, 17:11

get tom to make you 4... two in the middle on one side, and one on each end with teeth on the oposite side.

go 4wd... with self-righter.

and get brushless stuff... thought you wanted to make a proper robot this time?

**mattsdragons** · 20th September 2011, 17:17

YE CALUM! BUILD A PROPER ONE!

just forgetting the fact that i can build robots properly yet but still

**Mouldy** · 20th September 2011, 19:51

or you could buy a robot you dont know how to use and just start loads of new threads talking about all the projects you want to start that will never materialise? dribble dribble.