User:Laptop bird/Draft:West Coast drive

A West Coast drivetrain (also known as a West Coast drive, or WCD) is a form of drivetrain with a few distinctive features. Typically, a West Coast drive has six cantilevered wheels, with the center wheel directly connected to the output of the gearbox. The outer wheels are connected to the output by chain. The center wheel is usually slightly lower than the other wheels, allowing for greater maneuverability. It is also always a tank drive system, where power to each side of the robot is controlled independently.

West Coast drivetrains are commonly used in FIRST Robotics Competition robots. This form of drivetrain was popularized by FRC teams on the west coast of the United States (such as teams 60 and 254), hence the name.

Design

The most common form of West Coast drivetrain is a six-wheel drive with four- to six-inch diameter wheels. This gives adequate ground clearance for driving over most obstacles.

A WCD is best described as a center drop direct drive drivetrain with cantilevered wheels. This means that the center wheel is dropped a fraction of an inch, in order to allow for easier turning yet still maintain the stability of a 6-wheel drivebase. The robot would rock back and forth over the center wheel, so that only four wheels have non-inconsequential contact with the ground.

A benefit of having the gearbox output shaft connected directly to the wheel (direct drive) is that the robot will still maintain power even if all the chain broke on the robot.

The benefit of having cantilevered wheels is that it is easier to swap out the wheels for maintenance.