Tank steering

From Combat Robot

Tank steering (or differential steering) is a type of drivetrain layout that depends on changing motor speeds (differentially) to rotate the vehicle. It differs from "car steering" (AKA pivot steering) in that the wheels remain aligned with the longitudinal axis and do not swivel.

Design

A robot designed with tank steering requires the ability to apply power at different speeds and/or directions to opposite sides of the robot. This is typically accomplished by separate motors, controllers, and drivetrains for the left and right sides. Final drive may be via wheels, tracks, or walker legs. Moving the right side forward and the left side backward results in a left-hand spin. Moving both sides forward results in forward motion.

Tank steering can also be achieved with a single drive motor and a powered active differential, as seen in the Robot Wars competitor Firestorm.

The advantage of "tank" steering lies in the ability to make "zero radius" turns ("spinning on the spot"), as compared to the wide arc that pivot steering traces. Tank steering is the most popular method for robots, since maneuverability is of critical importance.