Approximating Ackermann Steering Geometry with a Trapezoidal Linkage
Ackermann geometry is a theoretical model for a steering system that has zero slip. It is achieved when all four wheels of a car are perpendicular to the same turning circle center. This Demonstration uses a common approximation for Ackermann geometry: a simple three-bar linkage. The linkage is arranged in a trapezoid so that the wheel on the inside of a turn will angle more than the outside wheel.[more]
The slider "toe" angles both the front wheels inward to allow the system to be optimized to Ackermann geometry for any turning radius.[less]
 Wikipedia. "Ackermann Steering Geometry." (Jul 23, 2013) en.wikipedia.org/wiki/Ackermann_steering_geometry.