Patent ID: 6856869

Claim:
An electric power steering device comprising: a neutral angle estimation means for estimating a neutral angle θc of a steering angle based on a sampling value θa of the steering angle when a predetermined sampling condition is established, the sampling condition being defined by a vehicle speed V, an angular velocity ω of the steering angle, a steering torque T, or relating values of the vehicle speed V, the angular velocity ω of the steering angle, and the steering torque T; and a sample reliability level calculation means for calculating a reliability y of the sampling value θa as the neutral angle θc based on the vehicle speed V, the angular velocity ω, the steering torque T, or the relating values of the vehicle speed V, the angular velocity ω of the steering angle, and the steering torque T when the sampling condition is established; wherein the neutral angle estimation means temporarily determines, confirms, or renews the value of the neutral angle θc based on the sampling value θa and the reliability level y.