Wikipedia

Steer-by-wire

Steer-by-wire, in the context of the automotive industry, is a technology or system that allows steering some or all of a vehicle's wheels without a steering column that turns the direction of those wheels mechanically. It is different from electric power steering or power-assist, as those systems still rely on the steering column to transfer some steering torque to the wheels.[3] It is often associated with other drive by wire technologies.

SpeedE, an academic concept car developed for studying drive-by-wire technologies[1][2]

A vehicle with a steer-by-wire system may be manually controlled by a driver through a steering wheel, a yoke, or any other controller which is connected to one or more electronic control units, which uses the input to control steering actuators that turn the wheels side-to-side, steering the vehicle. The steering wheel or yoke may be equipped with haptic feedback to simulate road feel and wheel resistance, and change depending on the vehicle speed or customizable settings.[3][4]

The safety of drive-by-wire systems is often ensured through redundancy, for example through redundant input sensors, redundant vehicle communication networks and power grids, redundant steering actuators per wheel, and fail-operational steering. If steering fails for one or even two wheels, the system can compensate with torque vectoring using the other available wheels.[5]

One-off vehicles

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Up-fitted drive-by-wire systems, such as the Paravan Space Drive, have been available since as early as 2003 for existing production vehicles.[6]

Several one-off vehicles and concept vehicles implemented steer-by-wire, such as the early-1990s Saab Prometheus,[7] 1996 Mercedes F200,[8] 2001 SKF Filo based on the Opel Zafira,[9] 2003 General Motors Hy-wire,[10] 2005 GM Sequel,[11] 2007 Mazda Ryuga,[12] and others.

Schaeffler Paravan Technologie has provided steer-by-wire systems for one-off racing vehicles, for example: a steer-by-wire Porsche Cayman GT4 raced the 2020 24 Hours of Nürburgring and finished 2nd place in its class and 29th overall; a steer-by-wire Mercedes-AMG GT3 raced the following year using the same system and finished 16th overall.[13][14]

Production combustion-engine vehicles

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Coupled with traditional steering

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See also: Steering § Four-wheel steering

Rear-axle-only steer-by-wire may be coupled with traditional front wheel steering for conditional four-wheel steering, reducing turning radius at low speeds and increasing stability at high speeds.[15] Purely mechanical four-wheel steering systems have been available in production cars since the mid 1980s, soon followed by computer-controlled systems in the late 1980s. Manufacturers implementing these systems included Citroën, Honda, Isuzu, Mazda, Mitsubishi, Nissan, Porsche, and Toyota. The popularity of four-wheel steering waned in the 1990s, with few models being offered in the early 2000s. Four-wheel steering systems reappeared in the late 2000s and 2010s in models by manufacturers including Acura, BMW, Nissan, Porsche, and Renault.[16] Car manufacturers that have offered rear-axle steering in the 2020s include Acura, Audi, Bentley, BMW, Cadillac, Ferrari, General Motors, Genesis, Lamborghini, Lexus, Mercedes-Benz, Porsche, and Rolls-Royce.[17]

One such rear-axle-only steer-by-wire system couple with traditional front steering was Quadrasteer. It was developed by Delphi and was offered starting 2002 on some General Motors trucks. Despite favorable reception the system was discontinued in 2005 due to poor market penetration of only 17 percent of sales of the same model, partially due to lack of familiarity with the system and partially due to its $1000 mark-up.[15]

Rolls-Royce vehicles based on the Architecture of Luxury platform, such as the Cullinan, Spectre, Ghost, and Phantom, have computer-controlled four-wheel steering.[18] The front wheel steering uses electric power assist[19] while an electronic system controls the rear wheel steering and turns them in the opposite direction of the front wheels when turning at lower speeds, and slightly in the same direction as the front wheels at higher speeds in order to increase stability.[20]

Without traditional steering

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The Infiniti Q50 was the first production road-vehicle without a traditional steering column, though one was still equipped as a backup.[2]

Steer-by-wire without the use of a steering column was first offered in a production car with the Infiniti Q50 in 2013.[4] The system has a backup steering column separated from the steering wheel with a clutch. The clutch connects the steering wheel to the steering rack in case of failure of the electronic steering sensors or actuators.[2] After negative reception the model was retrofitted with traditional hydraulic steering.[21] Steer-by-wire continued to be offered with the QX50 and QX55, and as late as 2022 it was being offered with the Infiniti Q60 coupe,[22] which was discontinued that year.[23]

Production electric vehicles

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Rolls-Royce Spectre
 
Lotus Eletre
 
GMC Hummer EV
 
Chevrolet Silverado EV
Production electric vehicles with rear SbW and a traditional steering column.
 
Tesla Cybertruck
 
Canoo Lifestyle Vehicle
 
REE P7-C class 4 electric truck
Production steer-by-wire electric vehicles with no steering column.

Production battery electric vehicles (BEVs) with rear-axle SbW coupled with traditional front-wheel steering include as of 2024 the Rolls-Royce Spectre,[24] Lotus Eletre,[25] GMC Hummer EV, and Chevrolet Silverado EV.[22]

Production BEVs with steer-by-wire with no steering column include as of 2024 the Tesla Cybertruck[26] which is sold at retail, and the Canoo Lifestyle Vehicle[27] and REE Automotive P7-C[28] which are sold to fleet operators. Planned production vehicles with no-steering-column SbW as of 2023 include: Lexus RZ 450e,[29] Nio ET9,[30] Toyota bZ4X,[22] and Geely Super Van.[31] As of 2023 Lotus,[25] Mercedes-Benz,[32] and Peugeot[33] plan to offer no-steering-column steer-by-wire cars in the mid to late 2020s.

References

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  1. ^ SpeedE - Forschungsplattform, ika - Institute for Motor Vehicles of RWTH Aachen University, 2016
  2. ^ a b c Lutz Eckstein (2016), "Future Trends for Automotive Steering Systems" (PDF), JTEKT Engineering Journal English Edition (1013E)
  3. ^ a b Chris Perkins (March 17, 2023), "How Toyota Is Making the Case for Steer-By-Wire", Road & Track
  4. ^ a b Jancer, Matt. "Take a Look Inside the First Steer-by-Wire Car". Archived from the original on 2014-03-16. Retrieved 2017-03-06.
  5. ^ Arunkumar Sampath, "Toward functional safety in drive by wire vehicles" (PDF), Mobility Engineering (December 2020)
  6. ^ Lydia Saß (July 26, 2023), "25 Jahre PARAVAN", barrierefrei-magazin.de
  7. ^ Gary Axon (May 21, 2018), "That time Saab built a car with a joystick", Goodwood
  8. ^ Adrian Padeanu (August 15, 2022), "Joystick-Driven Mercedes F200 Imagination Spotted With Its Many Screens", Motor1
  9. ^ Luca Ciferri (June 18, 2001), "Filo: is this the most high-tech independent car design?", Automotive News
  10. ^ Ralph King (October 1, 2003), "GM'S Race To The Future", CNN Money, archived from the original on February 25, 2007
  11. ^ Cesiel, D; et al. (April 3, 2006), Development of a Steer-by-Wire System for the GM Sequel, doi:10.4271/2006-01-1173
  12. ^ "Mazda Ryuga Concept Captures the Spirit of Motion", Bloomberg, January 10, 2007
  13. ^ "First race participation of a GT3 without steering column on the Nordschleife". www.schaeffler‑paravan.de. 10 May 2021. Retrieved 1 October 2021.
  14. ^ Bosch, Miguel (6 May 2021). "Schaeffler Paravan brings steer-by-wire system to GT3 with Mercedes-AMG entry in Nürburgring 24 Hours". www.gt‑report.com. Retrieved 1 October 2021.
  15. ^ a b Benjamin Hunting (January 5, 2021), "Why Did GM's Excellent Quadrasteer Full-Size Pickup Four-Wheel Steering System Simply Disappear?", DrivingLine
  16. ^ Aaron Severson (June 12, 2015), "Four-wheel steering demystified", Autoweek
  17. ^ Jonathon Klein (July 23, 2021), "How Exactly Does Four-Wheel Steering Work?", The Drive
  18. ^ Daniel Golson (October 18, 2022), "Rolls-Royce Spectre EV Is the Brand's Most Important Car Yet", CNET
  19. ^ Mark Vaughn (October 9, 2018), "Rolls-Royce Cullinan first drive: Seeing is believing", Autoweek
  20. ^ Mark Ewing (October 25, 2017), "First Drive: Rolls-Royce Phantom VIII Has No Rival, Equal Or Peer", Forbes
  21. ^ O'Kane, Tony (2 September 2014). "2016 Infiniti Q50 To Get 'Old Fashioned' Hydraulic Power Steering: Report". themotorreport.com.au. Archived from the original on 1 April 2017. Retrieved 13 April 2018.
  22. ^ a b c Jordan Golson (May 21, 2022), "What is Steer-by-Wire?", CapitalOne
  23. ^ Fitzgerald, Jack (2022-08-13). "Infiniti Q60 Is off to the Chopping Block for 2023". Car and Driver.
  24. ^ Britta O'Boyle (July 3, 2023), "Rolls-Royce Spectre review: The pinnacle of electric motoring", Pocket-lint
  25. ^ a b Georg Kacher (July 10, 2023), "2024 Lotus Eletre review: First international drive", Which Car?
  26. ^ Kevin Williams (November 30, 2023), "Huzzah, The Tesla Cybertruck Has Steer-By-Wire", InsideEVs
  27. ^ Frank Markus, "The 2024 Canoo Lifestyle Vehicle rocks the boat in our first drive review", USA Today
  28. ^ Ed Garsten (January 11, 2024), "REE Automotive delivers first totally by-wire commercial truck chassis", Forbes
  29. ^ Dave VanderWerp (September 20, 2023), "Lexus Continues to Hone Steer-by-Wire System, RZ Yoke Still a Year Away", Car and Driver
  30. ^ Mike Duff (January 3, 2024), "Nio Reveals ET9 EV Flagship, Promising Ultra-Fast 600-KW Charging", Car and Driver
  31. ^ "Chinese Farizon Auto launches its brand-new electric Super VAN, ready by 2024. Europe is the target", Sustainable Truck & Van, January 30, 2023
  32. ^ Anthony Alaniz (July 3, 2023), "New Mercedes S-Class Could Have Yoke Steering Wheel, More Physical Buttons", Motor1.com
  33. ^ Chris Chilton (January 6, 2023), "Hypersquare Steering On Road Cars By 2026, Peugeot CEO Says", Carscoops
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