PURPOSE: To improve stability and operability of a vehicle by a method wherein, in a title device for a 4-wheel steering vehicle, when the trouble of a suspension device is detected, rear wheel steering ratio characteristics are corrected to the side in phase with that of front wheels.
CONSTITUTION: When a trouble detecting means 135 detects abnormality of variation control of suspension characteristics based on signals from various sensors, variation control of a suspension is stopped, a fail safe valve is brought into an OFF-state, and an abnormality signal is outputted to a controller 110 for controlling steering of rear wheels. Meanwhile, the controller 110 for controlling steering of rear wheels selects and controls prestored rear wheel steering ratio characteristics based on detecting signals from various sensors 115 - 126. When a suspension trouble signal is inputted, rear wheel ratio characteristics are corrected to the side in phase with that of front wheels by means of a steering ratio characteristics correction means. This constitution enables ensurance of stability and operability even during the occurrence of the trouble of a suspension device.
MORITA TOSHIKI
HIRABAYASHI SHIGEFUMI
NAKAJIMA TOSHIO
