serious problem found - robot controller resets when jarred!

[Dave Flowerday]

Originally posted by seanwitte
There has to be a cap in the controller to filter out noise from the motors.

Yup, we have a controller apart here (it's not this year's, but I doubt they've changed much) and it has two good size caps near the power connector: a 100uF and a 1000uF.

Originally posted by KenWittlief
I dont know why there would be a large electrolytic cap in the robot controller - Its powered by a battery, which would have very little ripple

I recommend you watch the voltage readout on your OI sometime when you take your robot from a standing still position to full speed, or worse, full reverse to full forward. The voltage will drop by quite a bit. On our 4WD drive robot last year we would frequently see short dropouts to down near 8v when the match began, since our drivers were holding the sticks full forward. Those caps are in there to supply power when the battery voltage drops too low like that. Various parts of the RC use an 8v regulator which requires some voltage higher than 8 to maintain a steady output. Look at the PDF I'm attaching - the first graph is a plot of our battery voltage over 1 match at the Great Lakes Regional last year. The graphs following are current measurements from each of our motors. If it weren't for the above mentioned caps the RC would reset pretty much all the time.

But even still, caps are intended to smooth out noise and ripple on the power supply, not to hold it up during power interuption.

In my mind, a very short power interruption from a jolt is the same thing as noise. Noise causes the voltage to quickly drop and come back, just like bumping the breaker. What's the difference?