Four speed transmission

From FIRSTwiki

Synopsis

This elegant design, demo-ed by The KillerBees, has been described (by Dave Lavery) as "the slickest drivetrain yet." This is high praise coming from the leader of the team that was known for its simple gearbox design before this one came on the scene.

The picture below, of the demo board they had at the NASA/VCU Regional, says it all. Essentially two pneumatics allow for four positionings of the gears. It is cheap (<$100), easy to build, and robust. It was developed during the 2004 season, and we can expect to see a lot of it in 2005.

Possible improvement might be the addition of a Multiple motor drivetrain.

Development

Jim Zondag, the Killer Bee's Leader, talked about it in this ChiefDelphi post.

Thanks, I'm glad everyone likes our design. We have made two speed transmissions for the past several years. Each year we try to make them simpler and smaller. I found that with the kind of high/low shift range that I like to have (3:1 or more) that the robot would tend to lurch severely if you downshifted at high speeds. I really want to make a 3 speed with an intermediate gear to help this. It turned out it was easier to build a 4 speed than a 3 speed ( its really two small two-speeds in series). We focused the design around reliablity and ease of construction, the demo unit on display was made entirely by high school students in a few evenings using no special tooling. Once I had a design with 4 gears I was pretty much forced to automate the shifting in order to keep from overloading the driver. I talked with a few Automatic Transmission experts at DaimlerChrysler on how to do a shift scheduler and viola....a fully automatic electronic robot transmission. It really is pretty neat, providing a nearly flat power output across a very wide RPM band with a 5:1 total shift span.

Illustration