| 摘要 |
PURPOSE:To reduce a radius of gyration of a vehicle, and improve steering performance when the vehicle retreats by controlling rear wheels so as to be steered into a negative phase to front wheels at vehicle speed or less whose absolute value is lower than advance time prescribed vehicle speed when the vehicle retreats. CONSTITUTION:A servo valve 6 is controlled through a servo amplifier 17 by an electronic control circuit 11 according to respective detecting signals of a vehicle speed sensor 13 and a front wheel steering angle detector 16, and a steering angle of rear wheels 21 and 22 is controlled through a hydraulic actuator 7. This rear wheel steering angle is detected by a displacement detecting mechanism 18, and a detecting value is fed back to the servo amplifier 17. At this time, at prescribed vehicle speed or more when a vehicle advances, the rear wheels 21 and 22 are steered into the same phase with front wheels 19 and 20 according to vehicle speed and a front wheel steering angle, and at the prescribed vehicle speed or less, the rear wheels are steered into a negative phase to the front wheels, on the one hand, when the vehicle retreats, an absolute value of retreat vehicle speed is detected, and at vehicle speed or less whose absolute value is lower than the prescribed vehicle speed, the rear wheels 21 and 22 are controlled so as to be steered into the negative phase to the front wheels 19 and 20. |
