Steering assistance

Integrated in the system is the Servotronic, the electronic control of the speed-dependent steering power assistance. The EPS control unit determines the required steering power assistance from various input variables.

Characteristic maps for the support and damping characteristics are stored in the control unit. The values calculated from the input variables added to each characteristic curve result in the necessary steering power assistance. The electric motor and reduction gear provide the steering momentum.

Important input variables for steering power assistance are:

• Driving speed
• Steering torque on the driver side via steering torque sensor
• Steering angle speed
• Steering angle
• Operating temperature

On vehicles without steering-angle sensor, the EPS control unit calculates the steering angle. The calculation involves an algorithm on the basis of the wheel speed. The EPS learns the center position of the steering via the motor position sensor after a short driving time.