building a robot transport

[Bcahn836]

Originally Posted by bskll

my team is interested in building a motorized cart that help us transport our heavy robot.

the total amount of weight that the motors has to support is about 130 pounds for the robot and about 20-30 pounds for the cart it self.

we are planning to drive it with a simple drive system of two motors each individually connecting to a chain and then the chain will connect to 1 wheel each.

what gear ratio do you guys suggest? we don't need it to be fast here. we just need to help move along the robot.

thanks for any suggestion.

P.S. this is my first post.

Cool we are doing almost the same thing. For my senior project we too are building a motorized cart to carry the robot. Except we are using two wheel chair motors that were donated, we have the motors in a direct drive straight to the wheel chair wheel. Even might use the controls from the wheel chair too.

I have no idea on the correct gear ratio, we almost used the chain drive using an electric car motor, but my teacher brought out a donated motorized wheel chair and that quickly changed our minds.

GOOD LUCK.

[Koko Ed]

I would recommend making one as light and simple as possible.
While it is really cool to have one with alot of bell and whistles you should remeber that the more stuff you put on it, the more it weighs and the more it costs to transport is (not to mention the amount of space it takes up).
Think of keeping things more functional than fancy. That goes for the robot as it does the cart.

[[527]phil]

and don't forget that if you burn out a motor you'll be carrying the robot, or switching a motor, i think i'll just stick with an old fashioned cart cuz if it aint broke don't fix it, plus we got a load of freshmen to pull it for us , lol

[Ian W.]

Originally Posted by [527]phil

and don't forget that if you burn out a motor you'll be carrying the robot, or switching a motor, i think i'll just stick with an old fashioned cart cuz if it aint broke don't fix it, plus we got a load of freshmen to pull it for us , lol

Nonsense, that's the beauty of doing a chain drive, if a motor dies, take out the master link, put the chain somewhere safe, and now you have a slighty heavier push cart, which you can easily make back into a motorized cart should you find another motor.

That being the case, I suggest trying to use a CIM, or something else that will be in next year's KoP, or similar to something in it, because that way if it dies at a competition, you could possibly get replacements from other teams with a bit of trading. Or just use somethin that won't burn out under normal use (like a wheelchair motor, think of the trouble a company could get into for having their wheelchairs dying).

[sanddrag]

While motorized carts are really cool, I would not recommend one at all. When you're about to miss a match, a freewheeling cart will get your bot to the field much faster. Also, a non-motorized cart is much afer for everyone else in the pits.

[Doug G]

This comes up every year on our team, to build a motorized, super-duper, fancy dancy cart with toolboxes, battery charging stations, etc.. etc... I say keep it simple, light weight, and collapseable if possible. And just how is it getting to the competition - in the same crate as your robot? If the competition is too far to drive it to, are you willing to build a second crate to ship this cart in and pay for the extra drayage and feights charges, hmmm?

[Bcahn836]

we have always used our cart as a shipping crate for tools, and had it non motorized, but if you remember at Atlanta it was a pretty good distance and always up hill and the same 4 people got stuck pushing it from pits to playing Field, after last year i am tired of pushing that cart, so we are building a motorized on that will work like a lawn mower with a power assist. And we will still be able to use the cart as a shipping crate with tools we would just have to un hook the motors and unbolt the casters in front and board up the sides. Oh and it is only 10" bigger than the cart we used last year that fit in the pits just fine.