Angular Velocity Sensor
EPS equipped vehicle has a AVS in multifunction switch. AVS is composed of a set of photo interrupters (light emitting diode, photo TR and slitted disc).
The slitted disc has 18 outer slits for detecting steering wheel rotating direction and angular speed. An inner slit is provided for checking whether wheel position is within neutral or not. 2 sets of LED and photo TR check rotation of steering wheel, calculating degrees per time through on, off photo TR. An other set of LED and photo TR is used to sense wheel location. See Fig 1 .
With signal from sensors, EPS control module miscellaneously decides current flow to solenoid valve from 0A to 1A compensating steering wheel effort.