We’ve decided not to, but my team had tossed around the idea of 2-speed trannies on our bot. But, (apropo of nothing I guess…) what kind of programming would this take? Keep in mind, all you need to get the trannies to shift at the same time is a lock between individual shifters (like the throttles on a twin-engine boat), so that is no problem. But for the rest of it, if my team decided to do this next year, how hard would it be on the programmers?
It depends on how you are shifting. We use a pneumatic piston to shift. our trannies are parallel to each other, and we make an adapter so one piston shifts both sides at the same time. For us all we have to do is program a button on the controls to fire the piston via the festo valve. I don’t know if this will help, but thats as much as i know.
To shift a transmission (without a synchro) smoothly and properly would mean knowing the output shaft speed, input shaft speed, and motor speed. When a shift occurs, the clutch (however it is implemented) releases, and the transmission shifts. The input shaft speed changes when the gear is shifted. Knowing this new input shaft speed, match the motor speed to the input shaft speed (or at least get close). Re-engage the clutch…Bingo, smooth shift. It’s really just a matter of timing and acquisition, assuming the transmssion is robust and reliable (difficult to do at the FRC scale in 6 weeks).
Last year’s autonomous-free solution:
-Determine which relay output was triggered by the right drive joystick’s trigger.
-Plug relay for that solenoid into that relay output.
We’ll probably get fancier with it this season, since the Super Shifter’s built-in encoder gives us no excuse not to try more daring feats of shifting.
last year we just had one pneumatic solenoid that was split with a T joint and was connected to 2 pneumatic pistons that shifted. so they would always shift at the same time. The joystick on our trigger would control the shift
by the way, last year’s was a ball shift, which did not need some sort of timing mechanism