Trw Steering Systems Japan Co. Ltd.

Kenji Furukawa

In an electromotive power steering device, when input is received in a reverse direction, i.e., from the road, no assist torque connection is made in the reverse direction. The upper inertial moment is appropriately compensated for. Detection signals from each sensor are received and converted to an input torque, vehicle speed and phase angle. An assist torque command value is calculated from the input torque and the vehicle speed, and an angular velocity and angular acceleration are calculated from the phase angle. Subsequently, the inertial moment of the steering wheel is read and multiplied by the angular acceleration, thereby computing the inertial torque of the steering wheel. It is then determined whether the multiplication of the input torque and the angular velocity results in a positive value or a negative value. Only when the value is positive, correction is made of the assist torque command value. Consequently, no compensation for the upper inertial moment is made against the reverse input from the road. No malfunction arises.

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Nagoya, Japan

Kenji Furukawa