[Kevin Sevcik]

We used a similar design for a simple 2 speed tranny this year. We also had no problems at all shifting on the fly, but we ground the outsides of the gears to points so that the would mesh better. I will say that you need to be very careful about the size, pitch, strength, etc of your gears, as it's easier than you think to strip them.

Also, I'm also questioning the need of 3 gears, when you only really need a pushing and driving gear. I'm doubting that a mid-range would really help the acceleration of your robot THAT much, considering how short the field is, and how hard it is to make a turn at full speed.

That being said, I was thinking of a way to accurately shift one of these cylinders half way. I was thinking of using a split system of pneumatics with 60 psi and ~30 psi. shifting full distance would involve flooding one side with 60 psi. to shift half way, you lower the pressure on the extended side to a little more than 30 psi, then flood the other side with 60psi. Then P1V1=P2V2 does all the complicated positioning for you. The valve system would be complicated and/or impossible. I haven't looked into that yet. but it should work in theory, atleast.