motorized robot carts
 

Two friends and I on my robotic team have been assigned to make one for our team. All we have to work with is an electric wheel chair and basic robtics components in our shop. If your team has made one could you post pictures of them and how you guys made them any help is nice thanks.

Re: motorized robot carts
 

While I don't have any pictures, I can give you a basic description of the one I worked on a few years ago.

It was a very basic unit, we made a simple rectangular frame, the front had castors and was covered with a big sheet of diamond plate. At the rear there was a bump over the two drive wheels. It was setup like a basic tank drive robot using all old KOP components.

It worked decently well, one could ride on it with the robot, though we never brought it to competition as the legality was a bit sketchy, and we lacked the room to transport it. There are obvious drawbacks to a tank drive steering on a car, but it was still moderately maneuverable.

Re: motorized robot carts
 

We've had various proposals and sketches over the years. I thought one concept was pretty good: build a small "tractor" to pull a more typical non-motorized cart. Given sufficient power, that might also give you the option of adding an additional trailer for tools or batteries, or even seats for the drive team.

Re: motorized robot carts
 

As far as I have see, there are two main configurations. There is the afore mentioned tractor/trailer. This provides good stability, however driving the thing is a little bit more difficult, as the trailer doesn't follow the tractor's path exactly. A great advantage to this design is that you can make the tractor detachable. That way, if you run out of battery, you can just pull the tractor portion yourself.
The second configuration is a platform directly on top of the base. I saw one of these at the oregon regional. I seemed a little top heavy, so if you do this, beware of bumps. The platform for the robot was also really high up (approx 48 in), so lifting the robot may get a little awkward.

Re: motorized robot carts
 

Talk to T3 about it, I'm sure there is someone from their team lurking around here.

Re: motorized robot carts
 

While I don't have any specs on building one, you might want to try and get in touch with Team 1806, SWAT Team. They've had a motorized cart for some time now and it works pretty well. It's a regular cart with a segway-like attachment directly on the back. No joint inbetween, and they use a joystick/pedal to drive it.

Re: motorized robot carts
 

We have a motorized cart which is built on top of a motorized golf bag caddie. Unfortunately, the extra batteries needed take up a bit too much space so generally it is just pushed, which is no issue if one is going forwards, but it has an anti-rollback feature that makes backing up a slight issue. It is low to the ground and stable. The design allows for a couple of extra batteries to be stored in the bottom of the cart since the batteries are about the same height as the caddie's motor housing.

Re: motorized robot carts
 

Talk to 1075 about the coolest motorized robot cart ever.

Re: motorized robot carts
 

1899 built one for Logomotion. Wheelchair-based... A few pictures here:

http://www.flickr.com/photos/saintsr...57626693671452
http://www.flickr.com/photos/saintsr...57626693671452
http://www.flickr.com/photos/saintsr...57626693671452

I'll ping our mentor who worked on it... he has all the design details.

Re: motorized robot carts
 

Agreed 1075's cart is amazing, however, i believe it is extremely UNsafe. the drier has a hard time seeing it looks like. And having somthing like that in the pits seems very unsafe when there is a big crowd

Re: motorized robot carts
 

We took the motors and joystick off of an electric wheel chair, two car batteries, and a wooden table top the raises from about 18 inches to about 3 and a half feet off the ground. The rear two wheels are powered and the front two are casters. It has room for one person to ride. I'll put some pictures up later tomorrow.

Re: motorized robot carts
 

1293 modified a robot for parade duty in 2005, and it ended with me having to push around 200 pounds of robot and spare batteries mounted onboard for a half-mile to the parade end (including resistance from one of the gearboxes that was still engaged with its wheel). I had a lot of great memories with 1293...that was not one of them.

When your cart breaks*, what is your contingency for making sure the drive team can get the robot there safely and without exhausting themselves?

Something to consider.

*I'm not questioning your fabrication skills, but you know what will happen if you design with the assumption that it won't break....

Re: motorized robot carts
 

As someone who works team que at several events may I make a request on behalf of all field volunteers everywhere and ask you to please don't make one?
I know alot of teams think it's so cool to roll up tot he field in some tricked out cart pumping jams out of your expensive sound system and flashing lights but have you considered how tight the space is around the field and the pits, the amount of spectators milling around (especially children) and unless your team number is 67, 1114 or a 469 wouldn't that brainstorming be better served building a better robot (last I heard a team has never been picked because they had a cool robot cart but I wouldn't be surprise if a team wasn't picked because other teams found their cart annoying and their robot underwhelming)?
I know I'm being a big mean ol' jerk because of this but all I ask is you please think about this before you do this. It's one thing to make a cart that bring tools and batteries to the field but do you really need all that other stuff?

Re: motorized robot carts
 

I'm with Ed on this one. Yeah, they look cool, but is pushing/pulling a robot that difficult? Unless you can make one that is as small and can turn as tight as a normal cart, it probably not worth wasting your time on it.

And please don't be that team that blasts music from your cart. Its annoying and the rule book prohibits it.

Re: motorized robot carts
 

I completely agree, that is why this is an OFF SEASON project only. Its a great way to get your brain thinking before kickoff. We built ours in between regionals in 2008 as a present from our mentors for winning our first regional.