118 Crab Module Conference Presentation

[MasonMM]

Are you curious about crab drives?
Looking to expand your knowledge on swerve drive trains?
Want a chance to discuss the details of making a successful wheel box?

As a late addition to the 2009 FIRST Robotics Conference, The Robonauts will be presenting a session on the evolution of our crab drive wheel box. The official schedule has yet to be updated, but we will be presenting at 8AM Thursday Morning.

Lucien and I will be covering an in depth and technical view of our wheelbox along with justification for many of our teams design decisions. We will share insight from six years of using this crab module and why we've settled on the point we are at.

This presentation will be beneficial to any students or mentors who are thinking about building a crab drive. Building a crab drive can be a nightmare to undertake and we want to use this opportunity to help anyone by sharing everything we have learned. We will have wheel modules from our last 5 robots, a slew of spare pieces, and Pro/E models from 6 years of robots for all to play with.

I want to highly encourage team members to attend the Robotics conference, be it our session or any others. This is an excellent opportunity to learn from some of the top mentors and teams in the country. You can never learn too much!

Title: Robonauts’ Crab Drive Wheel Box
By: FRC Team #118, The Robonauts
Abstract:
The Robonauts first implemented a crab drive in the 2004 FIRST Robotics Competition. During each of the past six seasons the crab drive has evolved, resulting in a complex and powerful solution to omni-directional motion. The Robonauts’ wheel box is an infinite rotation module designed with weight, traction, and serviceability in mind. The Robonauts’ wheel box features adjustable steering sprockets for easy wheel alignment along with a coaxial design for steering and power transfer. Knowledge and theory gained from these FIRST robots has been used in the design of NASA’s Lunar Electric Rover. This 7,000 lb prototype vehicle uses six crab modules to effectively traverse a wide array of difficult terrains while carrying astronauts in a pressurized cabin.

Included in the session will be an in depth analysis of design choices and system features of our wheel box. Participants will gain insight into design decisions ranging from bevel gears to bearing selection to machining needs. There will also be a short overview of popular crab drives used by other FRC teams. This presentation will conclude by highlighting the transformation of design from FRC robots to a lunar rover.