Here is my introduction to Active Steering, correct me if i am wrong.
BMW Active Steering/Servotronic Power Assist Explained
As you may be familiar with a new term often associated with BMW cars, its called Active Steering (AS). This new technology was originaly conceived and introduced by BMW in the 5 and 6 series cars.
AS is not the same as Power Steering. It works slightly different than traditional streeing systems. With AS, you won't be crossing your arms over each other on the steering wheel as often during sharp cornering, and parking requires far fewer turns of the wheel. Just like aircraft technology, AS works as "steering-by-wire" mechanism. It uses sensors and mechnical gears to turn wheels from direction of the streeing.
When the system's sensors detect driver input at the steering wheel (turning motion), a computer analyzes the data and then sends the information to an electric motor and linkage. Based on this input, the front wheels are turned the appropriate amount.
AS is different than variable assist power steering, which only varies the amount of effort, not the actual steering ratio.
Servotronic provides gears for AS and it is a trademark for Servotronic INC in USA. This company also provides aircraft parts for different manufacturers.
Here is a diagram of how Active Steering works:
Sources: www.bmwusa.com
