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Rack and Pinion Steering

Rack and Pinion Steering

A DRIVER steering a car on a twisting road has two distinct tasks: to match the road curvature, and to keep a proper distance from the lane edges. Both

are achieved by turning the steering wheel, but it is not clear which part or parts of the road ahead supply the visual information needed, or how it is

used. Current models of the behaviour of real drivers1,2 or 'co-driver' simulators3–5 vary greatly in their implementation of these tasks, but all

agree that successful steering requires the driver to monitor the angular deviation of the road from the vehicle's present heading at some

'preview' distance ahead, typically about 1 s into the future. Eye movement recordings generally support this view6–9. Here we have used a simple

road simulator, in which only certain parts of the road are displayed, to show that at moderate to high speeds accurate driving requires that both a distant

and a near region of the road are visible. The former is used to estimate road curvature and the latter to provide position-in-lane feedback. At lower speeds

only the near region is necessary. These results support a two-stage model1 of driver behaviour.

Why do some cars respond so well to the driver? Great handling makes you feel safe and in control – and makes panic swerves and steering corrections as

effective as possible. The lightest touch of the wheel should direct the steering system effortlessly and precisely. As well as a well-designed suspension parts, it takes a good quality steering system and steering parts to achieve

excellent handling. If you’d like to know the anatomy of a steering system and how it supports handling, road holding and driveability, here is an easy

overview.