Victor braking feature

[Lloyd Burns]

We used braking on the FP motor / gearbox that drove a leadscrew to raise and lower a basket. That year, the idea was to catch a horizontal bar, and have the robot chin itself, hanging on the bar after the power went off. It would lose the scoring if it touched the ramp beneath within ten seconds of the end of the match.

Before we shipped, it worked acceptably, with about 80 pounds of robot suspended on the screw. After the screw wore in, however, the friction was low enough the the load could backdrive the motor, causing the body of our robot to descend slowly, for the longest ten seconds after the match. Had we allowed the basket to rise more slowly with a shorter lead, it would have had more friction as it unwound in descent, and it would have been harder to backdrive.

It is possible to backdrive a "braked" motor, more or less fast, depending on its load, and resistance in the shorting circuit.