Torque Sensor
When the steering wheel is turned, twist occurs in the torsion bar between the steering side of the input shaft and the output shaft on the road reaction force side.
Inductance is changed by the movement of the core. The amount this voltage changes (varies with the amount of movement and direction of the core) is amplified with the interface circuitry of the sensor coil and output to the EPS control unit as a steer signal.