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hi all
For my course at school, I can build some sort of non-combat robot, but i really cant think of any ideas
all i really want from it is to be able to drive it off road, look visually ok and not cost me an absolute bomb.
can anyone help me think of any ideas?
thanks all
matt
My off roader
http://www.youtube.com/watch?v=XOflL6MYpAk
Big wheels and high ground clearance are a must (perhaps borrow St Hammer :lame:)
Does it have to be offroad? If not you could just use your robot and say its for picking stuff up and moving it
or axe ones u could say to chop tomatos :)
imainly want it off road since there is a massive open green around my house which i could really have some fun at :)
build a saint type machine with huge wheels powered by wheel chair motors or similar. Couple of electronize and some nimh. Job done.
Not sure how much they are costing, but I remember seeing somewhere that Shane Swan had a supply of wheelchair motors, wheels speed controllers and possibly batteries (although I may be wrong on the batteries). Eric is using wheelchair motors and controller so it will work and if you don't want it for combat you might get away with using the batteries too.
i have 3 battreys for sale 2 are 12v ones 4000mah other 4700mah
the other one i think 9.6 v 3300 mah if that helps
I think you would really struggle with those batteries on wheelchair motors.
have all three :P
You would probably be ok. Wheelchair motors pull only a few amps when running normally. We have to over rate everything for combat because everything is pushed to it's limit.
I could go for overvolted Bosch 400's or 750's but then I would need a big speed controller
and a custom transmission. Why bother over volting? Get some wheel chair motors, run them at their rated voltage and attach some bigger wheels. Job done
I guess that's a possible idea but I doubt I would achieve the speed I want unless a go for something like a 2:1 increase
yes you would. An electric wheelchair has wheels of say 200mm. Up that to 600mm and suddenly you got a whole lot more speed from them
very true, and electrocize (or how ever you spell them) 30a esc's would do it ok at 24v?
or could i even get away with 15a with 25a fuses?
electronize. They should be ok as long as you don't do anything stupid like try and sit on the thing. If you were really concerned you could do the external relay modification to them and run them with 40A car relays.
if we are talking 40a car relays, then i have found that my 15a run fine with 25a fuses so in theory i could run a electronize 30a on 40a fuses?
Your 15A electronize should be fine.
ok then, just if i did want to have a ride on it, what amp would i need?
so do u want my battreys :P
i thought that this was meant to be a simple cheap school project? I wouldn't bother trying to build it to take a person, build it as light as possible with large wheels with a decent amount of torque. Anything more and the costs will rocket.
true, i got a rough idea in my head involving sla's, those esc's, wheel chair motors and bike wheels :)
That setup should work fine. As I said I wouldn't bother trying to complicate it by making it strong enough to ride on.
and some steel box tub for a chassis with some metal just as protection :)
I was suggesting SLA's rather than NiMH's just to keep the price down, also wasn't sure on how those would work with wheelchair motors but if Gary thinks they would be fine then he knows better than me and I would agree :D . Also the SLA's Eric runs if used at 12v are 40Ah and to get that sort of longevity would cost you a fair whack in NiMH's compared to the 40 quid or so I spent on SLA's
@ Blazerbotics.
What does that offroader use for motors and where did those tyres come from?
viewtopic.php?f=240&t=2955
Thats the build diary for it. Bosch 750's.
I may go for something omega style :)
@Haywire The wheels are from a quad bike trailer (ebay £55 for all 4, new about £60 each) 18 diameter. Its running boschs, origannly on 36v (in the videos) but ive since had them rewound and it seems to have lots more power, so i've dropped it to 24v as it was it lively on 36v, kept wheelying and rolling over forwards!
Matt, i really suggest you aim for the 50kg mark, any more than that you start needing heavyweight stuff. Pair of wheelchair motors, old 4qds (or the wheelchair controller) and a pair of sla's means it can be done cheaply, if you were to build Omega from scratch then your looking £2000
It won't be an omega replica, just something which is inspired by omega :)
I got a few different ideas in my head with a few different options to look at :)
There have been a few people that have built robots for school projects and nearly every single one came VERY close to failing. Why? Because of time and cash restraints. Plan to build something as simple and as easily as possible. Two wheelchair motors or windscreen wiper motors, basic speed controllers on a basic chassis with two large wheels will do the job. The teacher won't care if you are running 24v motors on 36v with 4WD, they will likely only care that it works.
That was what I found - originally I was going to build a featherweight with a pneumatic flipper for an Extended Project, but my ineptness and focusing on my antweights led to that going out of the window and I built an overhead thwackbot antweight weighing less than 100g instead.
All the teachers were so impressed with 'TINY ROBOT THAT WORKS~!' and the accompanying dossier of misinformation presented entirely in the third person that they didn't notice how rubbish it was, and I ended up getting quite good marks for it and my college offered me the use of the school hall to host an Antweight World Series, so...yep, go as simple as possible and perfect the design later on :) (or, in the case of my project, disassemble it and send the parts to Canada!)
That's the aim, keep it simple and cheap. Wheel chair motors I can get, pair of esc's ain't a problem and already have two sets if bike wheels. Then it's just sla's
Thankyou, I have plans for a small invertible one for playing around with at the local common.Quote:
Originally Posted by blazerbotics