Steering with four wheels

Quadrasteer is a new electronic four-wheel steering system from Delphi Automotive Systems.

As I write, a lorry outside our London Offices has unsuccessfully attempted to snake its way through the cramped Soho streets and crashed into the side of our building.

This sorry turn of events could so easily have been avoided had the lorry in question been fitted with Quadrasteer, Delphi Automotive Systems’ new electronic four-wheel steering system.

Scheduled to make its debut on a 2002 GM full size pick up truck, Delphi claims that the new system gives full size vehicles the turning circle and maneuverability of much smaller cars while improving stability, handling and control at higher speeds.

Four wheel steering is not an entirely new concept. Honda, Mazda and Mitsubishi have all introduced it in the past and then dropped it. The problem was that they designed it into sporty cars which already had excellent maneuverability. This is the first time the technology has been applied to larger vehicles, and many analysts are convinced that it’s going to be big.

Current vehicles use the front two wheels to steer. The rear wheels remain straight and can actually create resistance. However, with Quadrasteer, the rear wheels are electronically controlled according to the speed of the vehicle. At lower speeds, the rear wheels turn in the opposite direction to the front wheels improving parking maneuvers. At moderate speeds, the rear wheels remain straight or neutral, and at higher speeds, the rear wheels turn in the same direction as the front wheels improving vehicle stability.

The system also makes driving with a trailer a far less fraught experience, reducing trailer sway and meaning that the driver has to make fewer steering allowances for disturbances like gusts of wind and uneven road surfaces.

Quadrasteer has four main components – a front-wheel position sensor, steerable solid hypoid rear axle, electric motor-driven actuator, and control unit. Handwheel position and vehicle speed sensors continuously report data to the control unit, which in turn determines the appropriate angle of the rear wheels. Algorithms are then used to determine the correct phase of operation.

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