Dynamic all wheel steering (Courtesy: Audi)

Dynamic All Wheel Steering System In Modern Cars


What Is Dynamic All Wheel Steering System?

Function of steering mechanism is to effectively steer the vehicle with safety during its speed range without much effort. Moreover, it is the basic function of the steering system is to steer the vehicle straight and maintain it at that position. It should turn the vehicle at the driver’s will without them putting much efforts. It is also necessary that the moving vehicle is under driver’s control at all times. Dynamic all wheel steering even enhances this further. It, too, is controlled by the vehicle’s electronic suspension platform (ESP).

All Wheel Steering
All Wheel Steering

Besides, dynamic all wheel steering system treats the steer angle and directional stability as separate issues. At low speeds and on tight bends, the system significantly reduces steering effort. But it never disturbs it. An abrupt lane change at high speed does not even ruffle the vehicle. The driver always feels focused & isolates the feedback from the road.

Components:

  1. Electromechanical front axle steering
  2. Active superposition steering
  3. Electromechanical rear axle steering

Furthermore, dynamic all wheel steering comprises two different high-tech steering systems. The front axle includes strain wave gearing. In this, the ratio varies as a function of speed. However, at low speeds, the rear wheels turn by a spindle drive and two track-rods by up to five degrees against the direction of steering. This facilitates maneuvering and reduces the turning circle by about one meter to 11.8 meters.

Components - All wheel steering
Components - All wheel steering

At medium and high speeds, the dynamic all wheel steering system turns the wheels by up to two degrees in the direction of steering. This increases stability. The system matches the steering ratio optimally to the driving situation. It adjusts the ratio across a range of 9.5 to 17. On slippery surfaces, the system again stabilizes the vehicle by manipulating the steering at the front and rear axles.

Dynamic All Wheel Steering Operation:

In a conventional rack and pinion steering mechanism, when the driver makes a right turn,

  • Both the steering wheel and steering tube turn clockwise. This causes the pinion to rotate and in turn move the steering rack.
  • This action moves the rack sideways and pushes the tie rod.
  • The tie rod pushes the left steering knuckle and left-side front wheel to the left.
  • The right tie rod pulls the steering knuckle and right front wheel to the left.
  • However, the dynamic all wheel steering mechanism also slightly moves both the rear wheels to the right.
  • This allows the ease of turning and maneuverability at low speeds in compact spaces.

Advantages:

There are many advantages of dynamic all wheel steering system. Following are the advantages of using this mechanism in vehicles.

  1. Greater steering stability in the same direction. When the vehicle is going in a straight line, the all wheel steering provides greater stability and steadiness.  
  2. Optimized steering feedback: Dynamic all wheel steering mechanism allow noticeable road surface variations on the steering wheel. So, the driver gets a better feel of the road surface.
  3. Quick & sharp steering response: This system provides the driver with sharp steering response. This enables the driver to quickly steer away from the obstacles without losing control over the vehicle.
  4. Besides, enhanced handling by steering in the opposite direction.
  5. Ease of parking: Dynamic all wheel steering mechanism offers ease of steering ability; thereby provides ease of parking.
  6. Furthermore, it also reduces the turning circle radius/diameter by about at least one meter. Thus, the vehicle requires less space to turn. You can park your vehicle in compact spaces easily. This is particularly useful in congested cities where parking and maneuvering in smaller old cities is a daunting task.
  7. Dynamic all wheel steering also enhances stability. At medium and high speeds, it turns the wheels by up to two degrees in the direction of steering, for increased stability. It also matches the steering ratio optimally to the driving situation and adjusts it across a range of 9.5 to 17.

In conclusion, dynamic all wheel steering is an advanced type of steering gear mechanism which uses steering on all wheels of the car. This is the most dynamic driving technology in the vehicles to date.

All Images – Courtesy (Audi)

Watch the Dynamic All Wheel Steering system in action here:

Read More: What is Volvo dynamic steering system?>>

About CarBikeTech

CarBikeTech is a technical blog with experience of over 20 years in the automobile field. It regularly publishes specific technical articles on automotive technology.

Don't miss out on Automotive Knowledge