All-wheel steering

from Wikipedia, the free encyclopedia
All- wheel steering in motor sport : Fiat Stilo with all-wheel drive in an ice race of the Trophée Andros
All- wheel steering with a 3.10 m turning radius on a Multicar Tremo Carrier
Mercedes-Benz G5 Kübelwagen from 1937 to 1941 with all-wheel steering

All- wheel steering is a technique in motor vehicles in which all wheels are steered to change direction; In contrast to the common steering of only one axle, where usually only the wheels of the front axle are steered. In fork lift trucks , harvesters , front dumpers (haulers) and the like, the wheels of the rear axle are steered.

function

Only special vehicles that have to maneuver in a confined space are normally equipped with all-wheel steering. Examples are four-way forklifts that can move sideways instead of taking a curve and sweepers that can turn in the smallest of spaces.

The all-wheel steering increases the ability of special vehicles, such as extra-long heavy- duty transporters , to maneuver even in difficult spatial conditions.

In car -wheel steering is used, depending on the driving speed display the following functions:

  • Turning circle reduction when maneuvering by steering the rear wheels in opposite directions with relatively large steering angles (several degrees)
  • Increased agility at low and medium speeds by steering the rear wheels in opposite directions with small steering angles
  • Increased stability at higher speeds by steering the rear wheels in the same direction with small steering angles

The transition between the area of ​​agilization and stabilization depends on the tuning of the vehicle; it is in the range from approx. 50 to 100 km / h. When steering in the opposite direction, an increase in the yaw angular velocity is achieved, whereas when steering in the same direction this is reduced and the transverse acceleration builds up more quickly. Furthermore, the float angle is also reduced here, which also benefits driving stability.

technology

Drive for active rear wheel steering with integrated control unit from Aisin Seiki

Active rear-axle steering in cars use various technical implementations. A steering system similar to that on the front axle can be used ( rack and pinion steering, etc.), which adjusts both rear wheels via tie rods . In another implementation, the passive toe links on the rear axle are replaced by active actuators, so that both rear wheels each have their own drive. Furthermore, special steering linkages are used, which in turn are adjusted via a single drive. The systems used today are all steer-by-wire systems, i. H. it is controlled by an electric motor and there are no mechanical or hydraulic couplings to the front axle steering. This places special requirements on functional safety , in particular in accordance with ISO 26262 .

Various integration scenarios are conceivable for the actual steering function, i.e. the calculation of the rear axle steering angle from the vehicle parameters. All active systems known today have their own electronic control unit (also called “ECU” according to the English word) to control the system (adjustment function, diagnoses, etc.). The steering function can be placed on this control unit. Alternatively, the function is integrated elsewhere, e.g. B. in the control unit of the front axle steering or the vehicle dynamics control .

The above Steering function can be represented by various algorithms . Input variables are i. d. Usually the steering angle of the front axle and the driving speed . In the simplest case, it is a pre-control which, on the basis of the input variables, determines the so-called steering factor, i.e. the quotient of the rear axle to the front axle steering angle.

Various automotive suppliers have corresponding rear axle steering systems in their range:

history

In 1903 the Cotta Automobile Company from the USA produced steam cars with all-wheel drive and all-wheel steering.

In 1907 the Daimler-Motoren-Gesellschaft developed the Dernburg car with four driven and steered wheels. The Società Automobili Brevetti Angelino designed a prototype with all-wheel drive and all-wheel steering in 1927 , but it did not go into series production. In the 1930s, the Mercedes-Benz 170 VL and G5 off - road vehicles had all-wheel steering, as did two types of standard Wehrmacht cars up to 1940 .

The first mass-produced road car with all-wheel steering was the third generation Honda Prelude , which appeared in 1987. The steering worked mechanically with a planetary drive: with a small steering angle, the rear wheels were turned in the same direction as the front wheels, with large ones in opposite directions. Other cars with all-wheel steering include the Mitsubishi Sigma and Mitsubishi 3000 GT, as well as the Nissan 300ZX and the Nissan Skyline . The Mazda 626 in its third generation, the GD series, and other mostly Japanese cars were and are available with all-wheel steering on request. At BMW , between 1992 and 1996, the so-called active rear axle kinematics (AHK) was partly built in as standard (in the 850 CSi) or at an additional cost in the 8 series ( BMW E31 ) .

A new generation of all-wheel steering systems has been in use since the late 2000s . For example, BMW first introduced all-wheel steering as an option in the 7 Series at that time (integral active steering) ; this is also available in the new generation of the 7 series , as well as - also optionally - in vehicles of the 5 and 6 series . At Renault all-wheel steering is available as an option since 2009 (4CONTROL) , first in the Renault Laguna GT , below (also optional) in the model series Talisman , Mégane . and Espace In 2013 the Porsche 911 Turbo went . for the first time with standard all-wheel steering in series; The Porsche Panamera has also been available with all-wheel steering as an option since 2016 Audi has been equipping the Q7 with a system since 2014 . Japanese manufacturers also offer vehicles with all-wheel steering in the luxury segment, such as Infiniti in the QX70 (RAS - Rear Active Steering) model . and Lexus in the GS model With the Ferrari F12tdf , the Ferrari GTC4Lusso and the Lamborghini Aventador (S Coupé) , the Italian manufacturers also introduced this technology in the 2016/2017 model years.

See also

Individual evidence

  1. ↑ a b c d cars | AKC® - Active Kinematics Control - ZF Friedrichshafen AG. Retrieved April 4, 2017 .
  2. ↑ SAE Magazines: SAE Eye on Engineering: ZF Active Kinematic Steering. March 2, 2016, accessed April 5, 2017 .
  3. ↑ "Continental Automotive Systems. Facts & Figures 2009", page 37, section "The rear axle steering - Active Rear Axle Kinematics (ARK)." Continental AG , accessed on March 12, 2017.
  4. ↑ The electro-hydraulic rear axle steering eRAS (electric Rear Axle Steering System). Robert Bosch GmbH , accessed April 5, 2017 .
  5. ^ "Steering Impulses from the Rear Active Kinematics Control (AKC) for Passenger Cars", ZF ( Memento of March 13, 2017 in the Internet Archive ). ZF Friedrichshafen AG, accessed on March 12, 2017.
  6. ↑ Aisin Seiki: Active Rear Steering. YouTube video. October 2, 2016, accessed April 4, 2017 .
  7. ↑ a b Electronic four-wheel steering from Renault. Retrieved April 4, 2017 .
  8. ↑ Beverly Rae Kimes, Henry Austin Clark Jr .: Standard catalog of American Cars. 1805-1942. Digital edition . 3. Edition. Krause Publications, Iola 2013, ISBN 978-1-4402-3778-2 , pp. 382 (English).
  9. ^ Nick Georgano: The Beaulieu Encyclopedia of the Automobile, Volume 3 P – Z. Fitzroy Dearborn Publishers, Chicago 2001, ISBN 1-57958-293-1 (English)
  10. ↑ BMW 7 Series Sedan: All the facts. Retrieved April 4, 2017 .
  11. ↑ BMW 5 Series Sedan: Driving Dynamics & Efficiency. Retrieved April 4, 2017 .
  12. ↑ BMW 6 Series Coupé: Driving dynamics & efficiency. Retrieved April 4, 2017 .
  13. ↑ Renault TALISMAN - the coupe sedan. Retrieved April 4, 2017 .
  14. ↑ The new Renault MEGANE GT - first-class equipment. Retrieved April 4, 2017 .
  15. ↑ Renault ESPACE - equipment at the highest level. Retrieved April 4, 2017 .
  16. ↑ Porsche 911 Turbo S - rear axle steering - Porsche Germany. Retrieved April 4, 2017 .
  17. ↑ Stars by ZF - ZF Friedrichshafen AG. Retrieved April 4, 2017 .
  18. ^ Porsche Panamera - rear axle steering - Porsche Germany. Retrieved April 4, 2017 .
  19. ↑ Packages> Q7> Audi Germany. Retrieved April 5, 2017 .
  20. ↑ Infiniti QX70 Performance - Premium Crossover. Retrieved April 4, 2017 .
  21. ↑ News & Events, News. (No longer available online.) Archived from the original on February 22, 2017 ; Retrieved April 4, 2017 .
  22. ^ F12tdf: Racing Performance for the Road - Ferrari.com. (No longer available online.) Archived from the original on April 18, 2017 ; Retrieved April 4, 2017 (American English). Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / auto.ferrari.com
  23. ↑ GTC4Lusso - Ferrari.com. Retrieved April 4, 2017 (American English).
  24. ↑ Lamborghini Aventador S Coupé. Retrieved April 4, 2017 .