Introduction : Four-wheel steering, 4WS, also called rear-wheel steering or all-wheel steering, provides a means to actively steer the rear wheels during turning maneuvers.
It should not be confused with four-wheel drive in which all four wheels of a vehicle are powered. It improves handling and help the vehicle make tighter turns.
Production-built cars tend to understeer or, in few instances, oversteer. If a car could automatically compensate for an understeer/oversteer problem, the driver would enjoy nearly neutral steering under varying conditions.
4WS is a serious effort on the part of automotive design engineers to provide near-neutral steering. The front wheels do most of the steering.
Rear wheel turning is generally limited to 50-60 during an opposite direction turn. During a same direction turn, rear wheel steering is limited to about 10-1.50.
When both the front and rear wheels steer toward the same direction, they are said to be in-phase and this produces a kind of sideways movement of the car at low speeds.
When the front and rear wheels are steered in opposite direction, this is called anti-phase, counter-phase or opposite-phase and it produces a sharper, tighter turn.
Please find the following attachments"Four-wheel steering(FWS) seminar report/pdf/ppt report" here......
Attached Files for Direct Download
* Click on the 'file icon' or 'file name' to start downloading