pic: Speedy

[Donut]

Okay, Speedy officially started running today. Some problems I have encountered...

1. High gear is geared too high, it has so little power it can barely accelerate and can't turn the robot in high gear
2. The robot will not shift into high gear while moving

I will be changing the overall gearing lower to fix the first problem, and I hope the second one will just take care of itself. The transmission shifts into either gear while stationary, and shifts from high to low on the fly, but won't shift from low to high on the fly.

Video will come when I can get it working better.

[RyanN]

Originally Posted by artdutra04

Very cool - I like it! Once this is done, I would love to see video of it shifting from low gear to high gear.

Just don't forget about gear train efficiencies. It looks like there are eight gear/chain reductions per side, and all those losses can all really add up. Each Vex gear reduction will only be about 90-95% efficient, while each Vex chain reduction will be about 95% efficient.

I have a video of a Vex robot that is 2 speed with tank treads. If you want it, you can contact me.

[TheOtherGuy]

wow. just like everyone else said. very interesting

Originally Posted by Donut

I am worried about it being top heavy since there are 6 motors attached to the top layer, but with a battery and controller on the bottom I think it will balance out okay.

How fast did the battery die when you drove it around?

Originally Posted by Donut

It uses up gears from the standard kit and one expansion gear kit (2 12-tooths, 8 36-tooths, and 6 60-tooths). It uses two chain kits though; I think you could get enough sprockets from one, but it uses so much chain that I only had 2 inches of chain left from both kits combined (this after moving the encoders closer to one side so I had enough chain). It uses 2 metal kits, but if you're willing to cut many of the long pieces and shafts to length it could easily be done with 1.

gee, I wish I had that many accessory kits!

[Donut]

I didn't use the Vex battery as it was more difficult to connect. I haven't really tried to drain the batteries purposely or anything, but I can guarantee it runs perfectly fine for at least 5 minutes under heavy driving.