Editing Drive by wire

{{Short description|Automotive technology}}
{{Use mdy dates|date=July 2023}}
[[File:Erprobungsfahrzeug SpeedE der fka GmbH.jpg|thumb|right|SpeedE, an academic concept car developed for studying drive-by-wire technologies<ref name="SpeedEpapers"/>]]
'''Drive by wire''' or '''DbW''' in the  [[automotive industry]] is the [[technology]] that uses [[electronics]] or [[electro-mechanical]] systems in place of [[mechanical linkage]]s to control driving functions. The concept is similar to [[fly-by-wire]] in the aviation industry.<ref name="Assembly2010" /> Drive-by-wire may refer to just the [[ground propulsion|propulsion]] of the vehicle through [[electronic throttle control]],<ref name="Scheibert2023">{{cite book | doi=10.4271/2023-01-0581 | chapter=Challenges with the Introduction of X-By-Wire Technologies to Passenger Vehicles and Light Trucks in regards to Functional Safety, Cybersecurity and Availability | title=SAE Technical Paper Series | date=2023 | last1=Scheibert | first1=Klaus | last2=Kostarigka | first2=Artemis | last3=Dannebaum | first3=Udo | last4=Ambekar | first4=Abhijit | last5=Cai | first5=Wenlin | last6=Heidt | first6=Laurent | volume=1 | s2cid=258033364 }}</ref> or it may refer to electronic control over propulsion as well as [[steering]] and [[braking]], which separately are known as [[steer by wire]] and [[brake by wire]], along with electronic control over other vehicle [[driving]] functions.<ref>{{cite book |doi=10.1063/5.0113232 |chapter-url=https://pubs.aip.org/aip/acp/article-abstract/2452/1/030001/2824443/Overview-of-drive-by-wire-technologies-in |volume=2452 |issue=1|bibcode=2022AIPC.2452c0001P |s2cid=253697706 |chapter=Overview of drive by wire technologies in automobiles |title=INTERNATIONAL CONFERENCE ON TRENDS IN CHEMICAL ENGINEERING 2021 (ICoTRiCE2021) |date=2022 |last1=Pillai |first1=Arjun V. |last2=Manojkumar |first2=B. |series=AIP Conference Proceedings |page=030001 }}</ref>

Driver input is traditionally transferred to the motor, wheels, and brakes through a [[mechanical linkage]] attached to controls such as a [[steering wheel]], [[car controls#Throttle control|throttle]] pedal, [[hydraulic brake]] pedal, [[parking brake#Pedal or pull handle|brake pull handle]], and so on, which apply mechanical forces. In drive-by-wire systems, driver input does not directly adjust a mechanical linkage, instead the input is processed by an [[electronic control unit]] which controls the vehicle using [[electromechanical]] [[actuators]]. The [[human–machine interface]], such as a steering wheel, yoke, accelerator pedal, brake pedal, and so on, may include [[haptic technology|haptic feedback]] that simulates the resistance of hydraulic and mechanical pedals and steering, including [[steering kickback]]. Components such as the steering column, intermediate shafts, pumps, hoses, belts, coolers, [[vacuum servo]]s and master cylinders are eliminated from the vehicle. Safety standards for drive-by-wire are specified by the [[ISO 26262]] standard [[Automotive Safety Integrity Level|level D]].

== Properties ==
[[File:REE Automotive P7-C class 4 electric truck with Knapheide vocational body Work Truck Week 2024 facing left.jpg|thumb|right|alt=REE Automotive P7-C class 4 electric truck.|The [[REE Automotive|REE]] P7-C truck is the first production vehicle to be road-certified in the United States with all by-wire controls, including drive, steer, brake,<ref>{{citation |url=https://www.autoexpress.co.uk/news/362018/world-first-everything-wire-vehicle-breaks-all-mechanical-links-driver |title=World first 'everything-by-wire' vehicle breaks all mechanical links to driver |author=Chris Rosamond |date=January 12, 2024 |website=[[Auto Express]]}}</ref> and park-brake by-wire, collectively called x-by-wire.<ref name="Scheibert2023" />]]
Dispensing with mechanical linkages has several advantages: it reduces complexity and simplifies assembly; simplifies service and tuning; reduces the force required to engage inputs and allows it to be customized with [[haptic technology]]; allows for more [[Automotive design#Interior design|interior design]] freedom in the placement of input mechanisms; allows for automation of driving functions; reduces cabin noise by eliminating the acoustic linkage to the drive systems; and by reducing floor openings it improves the [[Automotive safety|crash behavior]] of the vehicle.<ref name="Naunheimer2011">{{citation |title=Automotive Transmissions: Fundamentals, Selection, Design and Application |edition=Second |publisher=Springer |author=Harald Naunheimer |isbn=978-3-642-16213-8 |doi=10.1007/978-3-642-16214-5 |year=2011 |display-authors=etal |chapter=9.1.3 Shift-by-Wire}}</ref> Because driver inputs can be overridden, safety can be improved by providing computer controlled intervention of vehicle controls with systems such as [[electronic stability control]] (ESC), [[Autonomous cruise control system|adaptive cruise control]] and [[Lane departure warning system|lane assist systems]].<ref name="Assembly2010">{{citation |url=https://www.assemblymag.com/articles/87508-wire-processing-drive-by-wire |title=Wire Processing: Drive-by-Wire |author=Austin Weber |date=March 26, 2010 |website=Assembly Magazine}}</ref>

Each drive-by-wire system leads to more actuator in the vehicle and therefore greater energy consumption. For instance, the drive-by-wire technology adds actuator motors to create the torque needed to turn the wheels, and a feedback transducer to create the "road feel" on the steering wheel.

Safety considerations require [[Redundancy (engineering)|redundancy]] of driver input sensors, [[CAN bus|vehicle communication network]]s, actuators,<ref name="Naunheimer2011" /> and other systems. Automotive safety standards such as [[ISO 26262]] require drive-by-wire [[Safety-critical system#Reliability regimes|fail-operational and fail-safe]] behaviors.<ref name="Sampath2020" />

== Safety and security ==
[[File:Space Drive Paravan.webm|thumb|Up-fitted drive-by-wire systems, such as the [[:de:Paravan|Paravan]] Space Drive, have been available since as early as 2003 for existing production {{nowrap|vehicles.<ref>{{citation |url=https://barrierefrei-magazin.de/artikel/25-jahre-paravan/ |title=25 Jahre PARAVAN |author=Lydia Saß |date=July 26, 2023 |website=barrierefrei-magazin.de}}</ref>}} Space Drive II is equipped with a redundant power system and {{nowrap|triple-[[Redundancy (engineering)|redundant]]}} communications and processors.]]
Failures in drive by wire systems can lead to potential hazardous situations where safety depends entirely on the vehicle's [[Safety-critical system#Reliability regimes|failure mode]]. The [[Aachen University]] Institute for Motor Vehicles (ika – [[:de:Institut für Kraftfahrzeuge Aachen|Institut für Kraftfahrzeuge Aachen]]), in collaboration with [[Mercedes-AMG]] and others, studies the operation, risks, and safety mechanisms of drive-by-wire systems through its drive-by-wire concept vehicle, SpeedE. Studied scenarios include loss of control over acceleration, brakes, or steering.<ref name="SpeedEpapers">{{citation |url=https://www.ika.rwth-aachen.de/de/kompetenzen/projekte/fahrzeugkonzepte-und-design/speede-de.html |title=SpeedE – Forschungsplattform |year=2016 |publisher=ika – Institute for Motor Vehicles of RWTH Aachen University}}</ref>

Early by-wire systems had mechanical backup systems in case the by-wire systems failed.<ref name="Scheibert2023" /> The modern drive by wire paradigm dispenses with mechanical backups, and relies on [[Redundancy (engineering)|redundancy]], [[Safety-critical system#Reliability regimes|fail-operational]] systems, and other safety and security measures: computational redundancy through [[Lockstep (computing)|lockstep CPUs]]; functional redundancy through modular design where the failure of one module is compensated by an identical module, for example by [[torque vectoring]] to compensate for a failed steering or braking module; multi-sensor fault detection; self-isolation of damaged systems; and fault-tolerant communication. Such fail-safes are specified by the [[ISO 26262]] standard [[Automotive Safety Integrity Level|level D]].<ref name="Sampath2020">{{citation |url=https://saeindia.org/jbframework/uploads/2020/12/Tech-Trends-Towards-Functional-Safety-in-Drive-By-Wire-Vehicles-compressed.pdf |title=Toward functional safety in drive by wire vehicles |author=Arunkumar Sampath |journal=Mobility Engineering |issue=December 2020}}</ref>

Assessment and standardization of drive-by-wire [[computer security]] has also taken place. Researchers demonstrated in 2011<ref>{{cite web |last1=Checkoway |first1=Stephen |title=Comprehensive Experimental Analyses of Automotive Attack Surfaces |url=https://www.youtube.com/watch?v=bHfOziIwXic |website=YouTube |date=August 15, 2011 |access-date=August 23, 2018 |archive-date=May 31, 2017 |archive-url=https://web.archive.org/web/20170531064515/https://www.youtube.com/watch?v=bHfOziIwXic |url-status=live }}</ref> and 2013<ref>{{cite web|url=https://www.forbes.com/sites/andygreenberg/2013/07/24/hackers-reveal-nasty-new-car-attacks-with-me-behind-the-wheel-video/|title=Hackers Reveal Nasty New Car Attacks—With Me Behind The Wheel (Video)|first=Andy|last=Greenberg|website=[[Forbes]] |access-date=2017-08-26|archive-date=2017-08-25|archive-url=https://web.archive.org/web/20170825000835/https://www.forbes.com/sites/andygreenberg/2013/07/24/hackers-reveal-nasty-new-car-attacks-with-me-behind-the-wheel-video/|url-status=live}}</ref><ref name="wired2015">{{cite magazine|url=https://www.wired.com/2015/07/hackers-remotely-kill-jeep-highway/|title=Hackers Remotely Kill a Jeep on the Highway—With Me in It|first=Andy|last=Greenberg|magazine=Wired |access-date=2017-03-06|archive-date=2017-01-19|archive-url=https://web.archive.org/web/20170119103855/https://www.wired.com/2015/07/hackers-remotely-kill-jeep-highway/|url-status=live}}</ref> that some systems in commercially-available vehicles are susceptible to [[Security hacker|hacking]], allowing for external control of the vehicle. Hacking demonstrations included remote activation of systems like the horn, windshield wipers, accelerator, brakes, and transmission.<ref name="wired2015" /> Modern standards such as the [[IT security standards#ISO/SAE 21434|ISO/SAE 21434]] standard and [[Regulation of self-driving cars#UNECE WP.29 GRVA|UNCE regulations 155, 156, and 157]] require dedicated [[cryptographic module]]s that encrypt all communication between the ECUs and the drive system components.<ref name="Scheibert2023" />

== Systems ==
[[File:Lotus Eletre 010 (cropped).jpg|thumb|right|alt=Lotus Eletre|A model of the [[Lotus Eletre]] with drive-, steer-, and brake-by-wire provided by [[ZF Friedrichshafen|ZF Group]]<ref>{{citation |url=https://www.iaa-mobility.com/en/newsroom/news/cars/zf-drive-by-wire |title=ZF presents MOBILITY by-wire technology at IAA |year=2023}}</ref> is planned for 2025<ref name="Kacher2024Lotus">{{citation |url=https://www.whichcar.com.au/reviews/2024-lotus-eletre-review-iirst-international-drive |title=2024 Lotus Eletre review: First international drive |date=July 10, 2023 |author=Georg Kacher |website=Which Car?}}</ref>]]
=== Brake by wire ===
{{Main|Brake-by-wire}}
A brake-by-wire system eliminates the need for a mechanical connection that transfers force between the brakes and a driver input apparatus such as a [[brake pedal|pedal]] or [[parking brake|lever]]. The three main types of brake-by-wire systems are: [[electronic parking brake]]s which have, since the turn of the 21st century, become more common; [[electro-hydraulic brake]]s (EHB) which can be implemented alongside legacy [[hydraulic brakes]] and as of 2020 have found small-scale usage in the automotive industry; and [[electro-mechanical brake]]s (EMB) that use no hydraulic fluid, which as of 2020 have yet to be successfully introduced in production vehicles due to their novel actuation methods.<ref name="Schramm 2020">{{citation |title=Vehicle Technology: Technical foundations of current and future motor vehicles |author=Dieter Schramm |display-authors=etal |chapter=5 Braking systems |doi=10.1515/9783110595703 |publisher=De Gruyter Oldenbourg |year=2020|isbn=9783110595703 |s2cid=216374738 }}</ref>

=== Shift by wire ===
{{Main|Shift by wire}}
Shift-by-wire employs electrical or electronic connections that replace the [[Linkage (mechanical)|mechanical connection]] between the driver's [[gearshift]] mechanism and the [[Transmission (mechanical device)|transmission]]. Since becoming commercially available in 1996, shift-by-wire has been commonly used in [[automated manual transmission]], and has later been implemented in [[semi-automatic transmission]] and [[automatic transmission]].<ref name="Naunheimer2011" />

[[Park by wire]] may be considered a form of shift-by-wire.<ref name="Naunheimer2011" /> Not to be confused with [[#Brake by wire|park-brake by wire]] which engages a [[parking brake]], park-by-wire engages the [[parking pawl]]. A parking pawl in a traditional automatic transmission has a mechanical link to the [[gear stick]] and locks the transmission in the park position when the gear-shift handle is set in "park". A park-by-wire system uses electronic commands sent to an actuator that engages the parking pawl.

=== Steer by wire ===
{{Main|Steer-by-wire}}
A vehicle equipped with a steer-by-wire system is able to steer some or all of its wheels without a [[steering column]] connected to the wheel axles. It is different from [[electric power steering]] or power-assist, as those systems still rely on the steering column to mechanically transfer some steering torque to the wheels.<ref name="RnT-sbw-Toyota">{{citation |url=https://www.roadandtrack.com/news/a43350167/toyota-steer-by-wire/ |title=How Toyota Is Making the Case for Steer-By-Wire |author=Chris Perkins |date=March 17, 2023 |website=Road & Track}}</ref>

A vehicle with a steer-by-wire system may be manually controlled by a driver through a steering wheel, a yoke, or any other steering apparatus which is connected to one or more [[electronic control unit]]s, which uses the input to control steering actuators that turn the wheels and steer the vehicle. The steering wheel or yoke may be equipped with [[haptic technology|haptic feedback]] to simulate road feel and wheel resistance, and change depending on the vehicle speed or customizable settings.<ref name="RnT-sbw-Toyota" /><ref name="Q50Wired">{{cite magazine|url=https://www.wired.com/2013/05/al-drivebywire/|title=Take a Look Inside the First Steer-by-Wire Car|first=Matt|last=Jancer|magazine=Wired |access-date=2017-03-06|archive-date=2014-03-16|archive-url=https://web.archive.org/web/20140316025422/http://www.wired.com/autopia/2013/05/al_drivebywire|url-status=live}}</ref>

=== Throttle by wire ===
{{Main|Electronic throttle control}}
Accelerate-by-wire or throttle-by-wire,<ref>{{citation|url=https://auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/drive-by-wire.htm |title=How Drive-by-wire Technology Works |author=John Fuller |date=April 28, 2009 |website=HowStuffWorks}}</ref> more commonly known as [[electronic throttle control]], is a system that actuates vehicle propulsion without any mechanical connections, such as cables, from the accelerator pedal to the throttle valve of the engine or other [[ground propulsion|propulsion]] systems. In electric vehicles, this system controls the electric motors by sensing the accelerator pedal input and sending commands to the power inverter modules.

== References ==
{{reflist}}

== External links ==
*[https://web.archive.org/web/20070930002022/http://www.isif.org/2075D04.pdf Fusion of redundant information in brake-by-wire systems, using a fuzzy Voter]

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[[Category:Automotive engineering|defaultsort]]
[[Category:Vehicle braking technologies]]
[[Category:Vehicle safety technologies]]
[[Category:Automotive steering technologies]]