Editing Anti-lock braking system (section)

=== Early systems ===
The concept for ABS predates the modern systems that were introduced in the 1950s. In 1908, for example, J.E. Francis introduced his 'Slip Prevention Regulator for Rail Vehicles'.<ref name="Lawes2014">{{cite book |author=Jon Lawes |title=Car Brakes: A Guide to Upgrading, Repair and Maintenance |url=https://books.google.com/books?id=Sod8AwAAQBAJ&pg=PT207 |date=31 January 2014 |publisher=Crowood |isbn=978-1-84797-675-8 |pages=207–}}</ref>

In 1920 the French [[automobile]] and aircraft pioneer [[Gabriel Voisin]] experimented with systems that modulated the hydraulic braking pressure on his aircraft brakes to reduce the risk of tire slippage, as threshold braking on aircraft is nearly impossible. These systems used a [[flywheel]] and valve attached to a hydraulic line that feeds the brake cylinders. The flywheel is attached to a drum that runs at the same speed as the wheel. In normal braking, the drum and flywheel should spin at the same speed. However, when a wheel slows down, then the drum would do the same, leaving the flywheel spinning at a faster rate. This causes the valve to open, allowing a small amount of brake fluid to bypass the master cylinder into a local reservoir, lowering the pressure on the cylinder and releasing the brakes. The use of the drum and flywheel meant the valve only opened when the wheel was turning. In testing, a 30% improvement in braking performance was noted, because the pilots immediately applied full brakes instead of slowly increasing pressure in order to find the skid point. An additional benefit was the elimination of burned or burst tires.<ref>{{cite web |url=http://www.flightglobal.com/pdfarchive/view/1953/1953%20-%201433.html |title=Non-Skid Braking |work=Flight International |date=30 October 1953 |pages=587–588}}</ref>

The first proper recognition of the ABS system came later with the German engineer Karl Wässel, whose system for modulating braking power was officially [[patent]]ed in 1928. Wässel, however, never developed a working product and neither did [[Robert Bosch]] who produced a similar patent eight years later.<ref name="Lawes2014"/>

A similar braking system called [[Decelostat]] that used [[dynamo|direct-current generator]]s to measure wheel slippage was used in railroads in the 1930s.<ref name=annual>{{cite book|title=Annual Report|year=1936|publisher=Westinghouse Air Brake Company|page=1|url=https://books.google.com/books?id=EPQeAQAAMAAJ&q=decelostat|access-date=24 November 2013}}</ref> By 1951, flywheel-based Decelostat was used in aircraft to provide anti skid in landings. The device was on trials first in the United States and later by the British.<ref>{{cite journal |title=Optimum Braking |journal=Flight International |date=8 February 1951 |volume=59 |issue=2194 |pages=167–168 |url=https://books.google.com/books?id=9gsnAAAAMAAJ |access-date=9 July 2021}}</ref> In 1954, ''[[Popular Science]]'' revealed that there was preliminary testing of the Decelostat system to prevent car swirling on a heavy brake by the [[Big Three (automobile manufacturers)|US car manufacturers in Detroit]]. However, there was no public information of the test results.<ref>{{cite journal |title=Brakes |journal=Popular Science |date=August 1954 |volume=165 |issue=2 |page=232 |url=https://books.google.com/books?id=ziADAAAAMBAJ&pg=RA1-PA232 |access-date=9 July 2021}}</ref>

By the early 1950s, the [[Maxaret|Dunlop Maxaret]] anti-skid system was in widespread aviation use in the UK, with aircraft such as the [[Avro Vulcan]] and [[Handley Page Victor]], [[Vickers Viscount]], [[Vickers Valiant]], [[English Electric Lightning]], [[de Havilland Comet|de Havilland Comet 2c]], [[de Havilland Sea Vixen]], and later aircraft, such as the [[Vickers VC10]], [[Hawker Siddeley Trident]], [[British Aerospace 125|Hawker Siddeley 125]], [[Hawker Siddeley HS 748]] and derived [[British Aerospace ATP]], and [[BAC One-Eleven]], and the Dutch [[Fokker F27 Friendship]] (which unusually had a Dunlop high pressure (200 Bar) pneumatic system in lieu of hydraulics for braking, nose wheel steering and landing gear retraction), being fitted with Maxaret as standard.<ref>{{cite web |url=http://www.flightglobal.com/pdfarchive/search.aspx?ArchiveSearchForm%24search=maxaret&ArchiveSearchForm%24fromYear=&ArchiveSearchForm%24toYear=&x=0&y=0 |title=Browse Flight's archive of Historic Aviation |website=Flightglobal.com |access-date=2014-08-26}}</ref> Maxaret, while reducing braking distances by up to 30% in icy or wet conditions, also increased tire life, and had the additional advantage of allowing take-offs and landings in conditions that would preclude flying at all in non-Maxaret equipped aircraft.

In 1958, a [[Royal Enfield Super Meteor]] [[motorcycle]] was used by the [[Transport Research Laboratory|Road Research Laboratory]] to test the Maxaret anti-lock brake.<ref name="Reynolds">{{cite book |last=Reynolds |first=Jim |title=Best of British Bikes |publisher=Patrick Stephens Ltd |year=1990 |isbn=1-85260-033-0 |url-access=registration |url=https://archive.org/details/bestofbritishbik0000reyn}}</ref> The experiments demonstrated that anti-lock brakes can be of great value to motorcycles, for which skidding is involved in a high proportion of accidents. Stopping distances were reduced in most of the tests compared with locked wheel braking, particularly on slippery surfaces, in which the improvement could be as much as 30%. Enfield's technical director at the time, Tony Wilson-Jones, saw little future in the system, however, and it was not put into production by the company.<ref name="Reynolds"/>

A fully-mechanical system saw limited automobile use in the 1960s in the [[Ferguson P99]] racing car, the [[Jensen FF]], and the experimental [[all-wheel drive]] [[Ford Zodiac]], but saw no further use; the system proved expensive and unreliable.

The first fully-electronic anti-lock braking system was developed in the late-1960s for the [[Concorde]] aircraft.

The modern ABS system was invented in 1971 by Mario Palazzetti (known as 'Mister ABS') in the Fiat Research Center and has become standard in almost every car. The system was called Antiskid and the patent was sold to Bosch who named it ABS.<ref name="Patent">{{US Patent|3707313A}} - Anti-skid braking systems patent accessdate: 16. July 2020</ref>