Editing Automation (section)

===Early history===
[[Image:Clepsydra-Diagram-Fancy.jpeg|thumb|upright|Ctesibius's clepsydra (3rd century BC)]]

It was a preoccupation of the Greeks and Arabs (in the period between about 300&nbsp;BC and about 1200&nbsp;AD) to keep accurate track of time. In [[Ptolemaic Egypt]], about 270&nbsp;BC, [[Ctesibius]] described a float regulator for a [[water clock]], a device not unlike the ball and cock in a modern flush toilet. This was the earliest feedback-controlled mechanism.<ref>{{Cite journal|last=Guarnieri|first=M.|s2cid=24885437|date=2010|title=The Roots of Automation Before Mechatronics|journal=IEEE Ind. Electron. M. |volume=4| issue=2| pages=42–43 |doi=10.1109/MIE.2010.936772 |hdl=11577/2424833 |hdl-access=free}}</ref> The appearance of the mechanical clock in the 14th century made the water clock and its feedback control system obsolete.

The [[History of Iran|Persian]] [[Banū Mūsā]] brothers, in their ''[[Book of Ingenious Devices]]'' (850&nbsp;AD), described a number of automatic controls.<ref name=Hassan>[[Ahmad Y Hassan]], [http://www.history-science-technology.com/Articles/articles%2071.htm Transfer Of Islamic Technology To The West, Part II: Transmission Of Islamic Engineering] {{webarchive|url=https://web.archive.org/web/20080218171021/http://www.history-science-technology.com/Articles/articles%2071.htm |date=18 February 2008 }}</ref> Two-step level controls for fluids, a form of discontinuous [[variable structure control]]s, were developed by the Banu Musa brothers.<ref>{{citation|title=Soft variable-structure controls: a survey|author=J. Adamy & A. Flemming|journal=Automatica|volume=40|issue=11|date=November 2004|pages=1821–1844|doi=10.1016/j.automatica.2004.05.017|url=https://www1.rmr.tu-darmstadt.de/pdf/flemming2004.pdf|access-date=12 July 2019|archive-date=8 March 2021|archive-url=https://web.archive.org/web/20210308124345/https://www1.rmr.tu-darmstadt.de/pdf/flemming2004.pdf}}</ref> They also described a [[Control theory|feedback controller]].<ref name=Mayr>[[Otto Mayr]] (1970). ''The Origins of Feedback Control'', [[MIT Press]].</ref><ref name=Hill>[[Donald Routledge Hill]], "Mechanical Engineering in the Medieval Near East", ''Scientific American'', May 1991, p. 64-69.</ref> The design of feedback control systems up through the Industrial Revolution was by trial-and-error, together with a great deal of engineering intuition. It was not until the mid-19th century that the stability of feedback control systems was analyzed using mathematics, the formal language of automatic control theory.{{Citation needed|date=May 2021}}

The [[centrifugal governor]] was invented by [[Christiaan Huygens]] in the seventeenth century, and used to adjust the gap between [[millstone]]s.<ref>{{cite web|title=Charting the Globe and Tracking the Heavens|url=http://www.princeton.edu/~hos/Mahoney/clarklec.html|website=Princeton.edu}}</ref><ref>{{cite book|last=Bellman|first=Richard E.|url=https://books.google.com/books?id=iwbWCgAAQBAJ&pg=PA36|title=Adaptive Control Processes: A Guided Tour|date=8 December 2015|publisher=Princeton University Press|isbn=978-1-4008-7466-8}}</ref><ref>{{cite book|last1=Bennett|first1=S.|title=A History of Control Engineering 1800–1930|publisher=Peter Peregrinus Ltd.|year=1979|isbn=978-0-86341-047-5|location=London|pages=47, 266}}
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