Patent ID: 7520365

Claim:
A steering apparatus for a vehicle, comprising: a steering wheel; a steering rod configured to give a steering angle of tires; a steering motor coupled to the steering rod and configured to drive the steering rod to control the steering angle; a steering reaction force generation motor coupled to the steering wheel and configured to give a steering feedback to a driver; a torque sensor configured to detect a rotational torque on the steering wheel; a steering angle sensor configured to detect a steering angle of the steering wheel; and a control unit, said control unit comprising; a generation unit configured to generate a drive signal as a measurement signal required to drive the steering feedback motor so as to forcibly turn the steering wheel a predetermined amount which does not substantially interfere with the driving of the vehicle; and an estimation unit configured to estimate a mechanical impedance of the driver based on outputs from the torque sensor and the steering angle sensor when a steering manipulation is applied in response to the turn of the steering wheel by driving the steering reaction force generation motor according to the measurement signal; wherein the control unit is configured to control the steering reaction force generation motor based on the estimated mechanical impedance, thereby giving a proper steering feedback to the driver.