Four-wheel steering system for road vehicle - has target value for control of steering of rear wheels in answer to steering movement of front wheels by addition and subtraction of operands determined by basic position of signals

摘要

The four-wheel steering system for a road vehicle has a front-wheel steering mechanism (14) controlled by the steering wheel, and a rear wheel steering mechanism (20). A sensor (26) determines the vehicle speed (V). There is a target value adjustment of the operands on the basic position of at least one vehicle operating condition (V, theta F, theta'F, psi') and the system adjusts a target value for the control of the steering of the rear wheels (18) by addition and subtraction of the operands. The value of the operands is restricted within acceptable ranges. A control device (24) controls the rear wheel steering mechanism on the basic position of the target value. A target value correction unit, when the adjusted target value is outside a predetermined acceptable range, adjusted in accordance with the vehicle speed (V), corrects the target value to a value within the range. USE/ADVANTAGE - The operands are restricted and also the target value for control of the steering of the rear wheels by addition and subtraction of the operands.