One speed vs Two speed gearboxes

[AdamHeard]

Originally Posted by asid61

Autoshifting is done by either current sensing or heat sensing on the main breaker. When the current spikes (or the heat) for an extended period of time, you shift down. You can find a curve fit for the graph of the main breaker current limit versus time, or just have hard limits and times. This prevents breaker blows.
Generally you only need to utilize this in a pushing match, and the driver gets distracted. You could potentially also use collision detection, where the driver is pushing on the joystick but the robot is not moving. Then the program shifts down after a couple seconds. Shifting up is manual.
There is a number of ways to accomplish autoshifting.

I know no team is autoshifting off heat currently.

I'm unsure any teams are using current (as you technically could with the jaguars).

Teams that autoshift now are primarily shifting based on encoder feedback, once they hit a certain rpm in low gear they shift up (for a full voltage output). Once they hit below a certain rpm in high gear (for full voltage output) they shift down. There is sometimes a timer on it to prevent gear hunting (rapid back and forth).

Easy current monitoring will make the down/up shift easier next year.

By checking rpm and assuming full voltage output, the above method was essentially shifting based on current.