Transmissions

[Max Lobovsky]

A software filter for the drive train is not a bad thing in itself, but a turbo button is not really the best solution. There is enough resolution in human movement of joysticks to be able to control any robot I have seen (We have a omniwheel holonomic drive with no feedback. It is likely one of the most difficult to control FIRST drivetrains that exists). All that is required is a good input/output curve. The only time a "turbo button" is actually neccesary is when the thing you are controlling actually has a wider raneg of outputs than you can reasonably input. The turbo button lets you effectively double your input range.

[UCGL_Guy]

Our team worked over the summer to ue 222's design - best shift on the fly made. After finally getting the bugs worked out they work beautifully. We stuck with the three speeds a low low a middle and a high.
Thanks to Brad and 222 -- we did modify and tweak your design somewhat and if time ever permits will share with others.

[Rombus]

Heres my whole take on the "Turbo Button" issue:
i would have set it up to be locked in high all the time then have a slow mode for Perscis movement to cap or get a tetra from the loading zone. We tried the 4 speed transmission this year but ended up having to lock it into 2nd gear and we did OK with it. I dint know the exact reasons why we chose not to go fully shifting, but i personally didn't see much of a need for a 4 speed tranny on such a small field.

[Dave.Norton]

Originally Posted by Max Lobovsky

We have a omniwheel holonomic drive with no feedback. It is likely one of the most difficult to control FIRST drivetrains that exists)

We used the same wheels, and after looking at your site it looks like we had an identical layout. One difference though, ours was very easy to control. When we prototyped it the drive wouldn't go in a straight line to save itself, problem with 3 points defining a plane, and four being over constrained. Which is to say every time it hit a bump it would steer into a new direction. By adding a rotational accelerometer and suspension to the platform we got it under control (little joke there) and now it is fun to drive.

[Veselin Kolev]

Team 1072 (Harker Robotics Team) used a TechnoKat style dog shifter this year. Two speeds, two CIMS, geared to go 6 feet and 11 feet per second. Man.. what a beauty. Of course we totally ignored the white papers and designed everything ourselves... just to improve even more on an already very good design. We first of all did not use a flex coupler, instead we put a chain sprocket directly onto the output shaft of the transmission. We also made the whole thing with .25" and .125" plates screwed together, you could literally take the shifter OUT by unscrewing 5 bolts. And the thing was sturdy... even thought the transmissions were tiny they could pack a punch. For the record, or robot in low can push TWO other robots with the kit transmission. And we did this during competition. That is how we know..

As for shifting, it was very smooth and quiet, no jolt or sudden lurch of the robot. I was thinking about putting sycros on if shifting was too rough, but we tested it and they shifted fine. I highly reccomend any teams with access to a mill and lathe with the proper tooling and the urge to make a 2 speed transmission to consider a dog-style shifter like this.