ELECTRIC POWER STEERING DEVICE

PROBLEM TO BE SOLVED: To improve active safety by restraining influences of cross wind disturbance to steering while securing a smooth traveling performance on a curved road in an electric power steering device. SOLUTION: This device is equipped with an estimation means 32 for separating a lateral gradient disturbance rb from other lateral disturbance cw among lateral disturbances of a vehicle for estimation from a steering angle δ, a yaw rate γ, lateral acceleration Gy, and vehicle speed V of the vehicle detected by a steering angle detecting means 22, a yaw rate detecting means 23, a lateral acceleration detecting means 24, and a vehicle speed detecting means 25 respectively based on a steering-vehicle system model of the vehicle. A steering assist torque generated to an electric motor 11 in a manner to restrain the lateral disturbance cw with the lateral gradient disturbance removed from the lateral disturbances of the vehicle is corrected from results estimated by the estimation means 32. COPYRIGHT: (C)2004,JPO