Jaguar Meltdown

[Joe Ross]

Originally Posted by boomergeek

I'm relatively new to FIRST (my second year). And I was kind of surprised that neither the speed controllers themselves nor the standard software for driving the speed controllers had sufficient defensive measures for preventing a full speed motors in one direction (with the momentum of a robot traveling 10 fps) being instantaneously subjected to full voltage in the reverse direction.

While not enabled by default, when using CAN you can set a voltage ramp rate.

[Al Skierkiewicz]

Dick,
We rarely will suggest "brake" mode be used on drive motors. In low center of gravity robots it is not as dramatic as in high center of gravity robots like last year. Brake mode will usually tip a robot over.

[boomergeek]

Originally Posted by Al Skierkiewicz

Dick,
We rarely will suggest "brake" mode be used on drive motors. In low center of gravity robots it is not as dramatic as in high center of gravity robots like last year. Brake mode will usually tip a robot over.

Tipping can even be an issue this year.
Our tall stylish robot helped get us an imagery award in Connecticut this weekend and had the crowd on the edge of their seats when it does a 2-5 foot reverse front wheelie coming over the bump. (But not a single rollover thanks to our driver). "FLOOR IT coming down the hill until all four wheels are back on the carpet!"

We used the voltage rate change of the CAN control.
The use of brake mode was an experiment by our programmers that made it in early in the season and never really got a good A vs B comparison.