Team 931 Omniwheels

[bheller]

Omniwheel Render
Omniwheel Picture

Click on the above links to both a render and actual picture of Team 931's new omniwheels. The outer plates were waterjetted and milled by a sponsor, but the rest was student-fabricated, including the shafts, hubs, spacers, and rollers. These wheels are a drop-in replacement for the 9" Skyway wheels. We used 60A durometer urethane for the rollers. It's extremely flexible stuff -a pain to machine but worth it due to the excellent traction. The weight of the robot actually deflects the profile of the rollers so much at the roller edges that the wheel profile very closely approximates a circle.

So we installed them on the robot the other day, and they worked _too_ well! Think about it - with an omniwheel you essentially have casters when the robot's turning. The rotational inertia causes the robot to keep spinning when you lay off the stick, just like casters, causing overshoot. We're pursuing a gyro (ADXRS series) to fix this. The robot turns MUCH faster now.

Many thanks go to the Technokats, whose Trick Wheel design inspired these wheels. At the end of the season, I'll post a White Paper on the design, with inventor files, .dxfs and bill of materials.

Whaddaya think?

Brandon Heller
Team 931 Mentor
Team 449 Alum