The four-wheel-steering automobile has several benefits. The system gives the driver a greater degree of control over the automobile. The driver gets a more forgiving vehicle over a wide variety of conditions. The system enables the driver to make sharp, smooth lane transitions. It also prevents yaw, which is the swaying of the rear end during sudden movements. Furthermore, the four-wheel-steering system gives a car increased maneuverability. This enables the driver to park the car in extremely tight quarters. With additional closed-loop computer operating systems, a car could be prevented from sliding out of control in abnormal icy or wet road conditions.
The system works by moving the rear wheels relative to the front-wheel-steering angle. The control system takes information about the front wheels* steering angle and passes it to the actuator in the back. This actuator then moves the rear wheels appropriately.
When the rear wheels are given a steering angle relative to the front ones, the vehicle can vary its lateral acceleration response according to the loop transfer function

where λ = 2q/(1 - q), and q is the ratio of rear wheel angle to front wheel steering angle [14]. We will assume that T1 = T2 = 1 second and ωn = 4. Design a unity feedback system, selecting an appropriate set of parameters (λ, K, ζ) so that the steering control response is rapid and yet will yield modest overshoot characteristics. In addition, q must be between 0 and 1.

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1+(1+ A)T;s+ (1+A)T2s G(s)G(s) = K- [1 + (24/w,s + (1/w,)s']