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The front wheel steering system of conventional vehicle fails to keep the vehicle stable at high speeds and prove futile for heavy vehicles like tracks and trailers, especially in tight space. But if the rear wheels too could be steered, manoeuvrability of the vehicle will be enhanced. This results in the evolution Four-wheel steering (4WS). In 4WS, rear wheel are also steered in combination with the front wheels. This system helps in achieving superior cornering stability, improved steering responsiveness and precision, high -speed straight-line stability and a smaller turning radius and tight-space manoeuvrability at low vehicle speed range. Four-wheel steering is of course a beneficial technology. Due to the high cost of manufacturing and complexity in design the 4 WS system is fitted only to certain heavy and special utility vehicles. But the advancing development in electric steering system, the future may see more cars fitted with rear wheel steering.
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hai...thanks for the topic...i would like to present it as my college seminars...could you please provide me with more information on the topic..thanks in advance..
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What is Four-Wheel Steering (4WS) ,Quadrasteer?
Four wheel steering is a system that allows the rear wheels to turn for maneuvering, rather than just follow the front wheels. 4WS isn't new, you might remember it as an option on Honda Preludes in the late 1980's and early 1990's.
GM's Quadrasteer Features
The Quadrasteer steering system offers a 21% reduction in turning radius. So if a vehicle is capable of making a U-turn in a 25-foot space, Quadrasteer allows the driver to do it in about 20 feet.
Computer-controlled Quadrasteer can be switched on and off and has an effective trailer towing mode.
A computer determines how much and in which direction the rear wheels should move, and whether the rear wheels should turn the same direction as the front wheels or in the opposite direction. The movement is variable up to a couple of inches.
At slow speeds, the rear wheels move the opposite direction of the front wheels. This makes for easier parking and maneuvering.
At highway speeds, the rear wheels move in the same direction as the front wheels for easier lane changing. If you're pulling a trailer you'll really appreciate this feature, since it allows your vehicle to change lanes without the snaking-effect you'd normally experience.
In order to accommodate the steering mechanism and wheel movement, the Sierra Denali's track and fender width are wider than its conventional counterpart--but it's not as wide as the rear of a dually pickup.
Whether you are going off road, pulling a boat or trailer, driving on the Interstate, or parking in a tight spot, you'll notice a big difference in maneuverability when the rear wheels take part in the steering. Look for an increasing number of vehicles to be equipped with this maneuver-enhancing feature.
read more
monstergtarticles/steering_4_wheel.php
en.wikipediawiki/Steering
