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.