FOUR-WHEEL STEERING WHEEL

PROBLEM TO BE SOLVED: To provide a four-wheel steering vehicle in which an involving ratio of a driver to a rear wheel steering amount is enhanced so as to improve maneuverability and steering feeling. SOLUTION: A rear wheel steering ratio base value setting part 52 sets a rear wheel steering ratio base value on the basis of a vehicle speed signal inputted from a vehicle speed sensor 8. A rear wheel steering angle base value setting part 53 sets a rear wheel steering angle base value on the basis of the output of the rear wheel steering ratio base value setting part 52, and of a front wheel steering signal inputted from a steering angle sensor 15. A target rear wheel steering angle calculation part 55 calculates the target steering angle of the right and left rear wheels on the basis of the output of the rear wheel steering angle base value setting part 53, and of a rear wheel steering command value. A drive current generation part 56 generates a drive current with respect to a rear wheel turning mechanism 6 on the basis of the calculation result of the target rear wheel steering angle calculation part 55, and of a rear wheel turning amount signal inputted from rear wheel turning sensors 22rl, 22rr. An output interface 57 outputs the drive current generated in the drive current generation part 56 to right and left rear wheel steering actuators 21rl, 21rr. COPYRIGHT: (C)2009,JPO&INPIT