[ontrack2]

much simpler, it is basically an electric motor that attaches to the steering shaft.

Two sensors on the steering rack are used. One sensor monitors driver input from the steering wheel. As soon as the wheel is turned, the steering module provides power to an electric motor that moves the steering gear. The second sensor monitors the steering gear position and provides feedback on correct operation to the steering module. Other inputs such as vehicle speed or vehicle lateral acceleration can be used to modify steering assist for better steering feel.

The electric steering unit is still connected to the steering wheel by a steel shaft, but this is only used to provide input to the sensor during normal operation. If the steering module detects a fault, it shuts down the electric motor and the steel shaft allows the vehicle to still be steered.