| 摘要 |
In a four-wheel steering system for a vehicle a target value for controlling turning of the rear wheels (3,4) in response to turning of the front wheels (1,2) is determined by adding and subtracting a plurality of correction terms which are determined on the basis of running state values ( THETA F, PSI ', THETA 'F2) other than the vehicle speed (V) to and from a base term (G4.f4(V)) which is determined according to the vehicle speed (V). The base term is set according to the vehicle speed so that the rear wheels (3,4) are turned in the reverse phase in a low vehicle speed range and in the same phase in a high vehicle speed range, and each of the correction terms is a product of a function of the corresponding running state value ( THETA F, PSI ', THETA 'F2) and a control gain (f1(V),f2(V),f3(V)) determined according to the vehicle speed. The base term (G4.f4(V)) and the control gains (f1(V),f2(V),f3(V)) of at least one of the correction terms are fixed to respective predetermined values and the target value (TG THETA S1) is determined on the basis of the base term and the correction terms thus obtained when it is determined that the vehicle is making a sharp deceleration. <IMAGE> |
