Tread and brownouts

[cbale2000]

Originally Posted by mrnoble

running Brecoflex

Originally Posted by mrnoble

the pulleys are cantilevered, WCD style.

In my opinion, and having used treads (Brecoflex specifically) on a number of robots, this is asking for trouble. In theory you can make cantilevered pulleys work, but you have to have some VERY ridged shafts. The problem with doing this on tread drive is that any sort of flex in the shafts or change in the relative position of the pulleys can drastically increase the friction of the system, which can, amongst other things, cause increased current draw on the motors. That 1/2" of deflection may not seem like a lot, but what's happening is the contours on the back side of the tread is grabbing unevenly on the pulleys, causing higher friction than normal; this will also, very likely reduce the lifespan of the shafts/bearings/pulleys in your drive. Additionally, having the pulleys cantilevered leaves you more vulnerable to having a tread to pop/break off your drive.

Now, that said, your current gear reduction may also be a factor here, when my team used to use tank treads, we would gear the system to run at, maybe, 10fps tops when using 4 CIMs. In 2006 we got away with a bit higher speeds by adding a pair of Mini Bike motors ("Big CIMs") to the drive, but even then you should almost never plan to be one of the faster robots on the field while running tank treads. Lowering the reduction on the gearbox/belts may help offset the efficiency loss enough to save some battery life.