Editing Radio control

{{short description|Use of radio signals to remotely control a device, vehicle or drone}}
[[Image:MQ-1 Predator unmanned aircraft.jpg|thumb|upright=0.8|US Air Force [[MQ-1 Predator]] drone flown remotely by a pilot on the ground]]
[[Image:Md4-200.jpg|thumb|upright=0.8|[[Quadcopter]], a popular radio-controlled toy]]

'''Radio control''' (often abbreviated to '''RC''') is the use of [[control signal]]s transmitted by [[radio]] to [[remotely operate]] a device. Examples of simple radio control systems are [[garage door opener]]s and [[keyless entry system]]s for vehicles, in which a small handheld radio transmitter unlocks or opens doors.  Radio control is also used for control of [[model vehicles]] from a hand-held [[radio transmitter]]. [[Industrial organization|Industrial]], [[Military organization|military]], and [[scientific research]] organizations make use of radio-controlled vehicles as well.  A rapidly growing application is control of [[unmanned aerial vehicle]]s (UAVs or drones) for both civilian and military uses, although these have more sophisticated control systems than traditional applications.

==History==
The idea of controlling unmanned vehicles (for the most part in an attempt to improve the accuracy of [[Torpedo|torpedoes]] for military purposes) predates the invention of radio. The latter half of the 1800s saw development of many such devices, connected to an operator by wires, including the first practical application invented by German engineer [[Werner von Siemens]] in 1870.<ref>H. R. Everett, Unmanned Systems of World Wars I and II, MIT Press - 2015, pages 79-80</ref>

[[File:Tesla boat1.jpg|150px|thumb|left|In 1898, Tesla demonstrated a radio-controlled scale boat.]]
Getting rid of the wires via using a new wireless technology, radio, appeared in the late 1890s. In 1897 British engineer Ernest Wilson and C. J. Evans patented a radio-controlled torpedo or demonstrated radio-controlled boats on the [[Thames river]] (accounts of what they did vary).<ref>H. R. Everett, Unmanned Systems of World Wars I and II, MIT Press - 2015, page 87</ref><ref>{{Cite book |url=https://books.google.com/books?id=fNjgCgAAQBAJ&q=Wilson+1897+Torpedo&pg=PA87 |title=Unmanned Systems of World Wars I and II |isbn=9780262029223 |last1=Everett |first1=H. R. |date=6 November 2015|publisher=MIT Press }}</ref> At an 1898 exhibition at [[Madison Square Garden]], [[Nikola Tesla]] demonstrated a small boat that used a [[coherer]]-based radio control.<ref>[[Tapan K. Sarkar]], '' History of wireless'', John Wiley and Sons, 2006, {{ISBN|0-471-71814-9}}, p. 276-278.</ref> With an eye towards selling the idea to the US government as a torpedo, Tesla's 1898 patent included a clockwork frequency changer so an enemy could not take control of the device.<ref>{{cite patent |country=US |number=613809 |pubdate=1898-11-08 |title=Method of and apparatus for controlling mechanism of moving vessels or vehicles |inventor1-last=Tesla |inventor1-first=Nikola}}</ref>

[[File:Telekino receptor.JPG|thumb|The ''Telekino'', invented by Leonardo Torres Quevedo in 1903, which consisted of a [[robot]] that executed commands transmitted by electromagnetic waves.]]
In 1903, the Spanish engineer [[Leonardo Torres Quevedo]] introduced a radio based control system called the "''Telekino''"<ref>[[Tapan K. Sarkar]], '' History of wireless'', John Wiley and Sons, 2006, {{ISBN|0-471-71814-9}}, p. 97.</ref> at the [[Paris Academy of Sciences]]. In the same year, he applied for several patents in other countries.<ref>Torres, Leonardo, "[https://worldwide.espacenet.com/patent/search/family/001377220/publication/FR327218A?q=pn%3DFR327218A FR327218A Système dit telekine pour commander à distance un mouvement mécanique.]", ''Espacenet'', 10 December 1902.</ref><ref>Torres, Leonardo, "[https://worldwide.espacenet.com//publicationDetails/originalDocument?CC=GB&NR=190327073a&FT=D GB190327073 (A) ― Means or Method for Directing Mechanical Movements at or from a Distance.]", ''Espacenet'', 10 December 1903.</ref> It was intended as a way of testing [[Astra-Torres airship]], a dirigible of his own design, without risking human lives.<ref>Randy Alfred, "[https://www.wired.com/2011/11/1107wireless-remote-control/ Nov. 7, 1905: Remote Control Wows Public]", ''Wired'', 7 November 2011.</ref> Unlike the previous mechanisms, which carried out actions of the 'on/off' type, Torres established a system for controlling any mechanical or electrical device with different states of operation. This method required a transmitter capable of sending a family of different [[Code word (communication)|code word]]s by means of a binary [[telegraph key]] signal, and a receiver, which was able to set up a different state of operation in the device being used, depending on the code word. It was able to select different positions for the [[steering engine]] and different velocities for the [[propelling engine]] independently, and also to act over other mechanisms such an [[electric light]], for switching it, and a [[flag]], for raising or dropping it, at the same time,<ref name="Yuste2008">A. P. Yuste. ''[https://pdfs.semanticscholar.org/4e50/0c55919cb5188ea379033bde77ac7aa2de2b.pdf Electrical Engineering Hall of Fame. Early Developments of Wireless Remote Control: The Telekino of Torres-Quevedo],''(pdf) vol. 96, No. 1, January 2008, Proceedings of the IEEE.</ref> and so up to 19 different actions.<ref>{{cite web|title=1902 – Telekine (Telekino) – Leonardo Torres Quevedo (Spanish)|date=2010-12-17|url=https://cyberneticzoo.com/early-robot-enabling-technologies/1902-telekine-telekino-leonardo-torres-quevedo-spanish/}}</ref> In 1904, Torres chose to carry out the first test on a three-wheeled land vehicle with a range of 20 to 30 meters.<ref>H. R. Everett, Unmanned Systems of World Wars I and II, MIT Press - 2015, pages 91-95</ref> In 1906, in the presence of an audience which included King [[Alfonso XIII]] of Spain, Torres demonstrated the invention in the [[Port of Bilbao]], guiding the electrically powered launch ''Vizcaya'' from the shore with people on board, which was controlled at a distance over 2 km.<ref>{{Cite book |url=https://books.google.com/books?id=wkYOrgEACAAJ |title=Unmanned Systems of World Wars I and II |isbn=9780262029223 |last1=Everett |first1=H. R. |date=6 November 2015|publisher=MIT Press }}</ref>

In 1904, ''Bat'', a [[Windermere]] steam launch, was controlled using experimental radio control by its inventor, [Jack Kitchen]. In 1909 French inventor [Gabet] demonstrated what he called his "''Torpille Radio-Automatique''", a radio-controlled torpedo.<ref>{{cite web |url=http://www.ctie.monash.edu.au/hargrave/rpav_home.html#Gabet |title=Remote Piloted Aerial Vehicles |first=Russell |last=Naughton |website=www.ctie.monash.edu.au |access-date=2006-12-30 |archive-url=https://web.archive.org/web/20061208003823/http://www.ctie.monash.edu.au/hargrave/rpav_home.html#Gabet |archive-date=2006-12-08 |url-status=live}}</ref>

In 1917, [[Archibald Low]], as head of the secret [[Royal Flying Corps]] (RFC) experimental works at [[Feltham]], was the first person to use radio control successfully on an aircraft, a [[1917 Aerial Target]]. It was "piloted" from the ground by future world aerial speed record holder [[Henry Segrave]].<ref>{{Cite web |url=https://www.iwm.org.uk/history/a-brief-history-of-drones |title = A Brief History of Drones}}</ref> Low's systems encoded the command transmissions as a countermeasure to prevent enemy intervention.<ref>"The Dawn of the Drone" Steve Mills 2019 Casemate Publishers. Page 189 "In order further to safeguard against outside interference I may have a number of inertia wheels of variable speed, only one being correctly adjusted to pick up the timed signals and actuate the mechanism."</ref> By 1918 the secret [[D.C.B. Section of the Royal Navy's Signals School, Portsmouth]] under the command of [[Eric Robinson V.C.]] used a variant of the Aerial Target’s radio control system to control from ‘mother’ aircraft different types of naval vessels including a submarine.<ref name=adm253>UK National Archives ADM 1/8539/253 Capabilities of distantly controlled boats. Reports of trials at Dover 28 - 31 May 1918</ref>

[[File:USS Iowa Radio Gear.JPG|150px|thumb|left|alt=Black-and-white picture of a cabin. In a corner, intricate apparatus is mounted on a wall above a desk|Radio control gear invented by John Hays Hammond, Jr. installed in the battleship USS ''Iowa'' (1922)]]
During World War I American inventor [[John Hays Hammond, Jr.]] developed many techniques used in subsequent radio control including developing remote controlled torpedoes, ships, anti-jamming systems and even a system allowing his remote-controlled ship targeting an enemy ship's searchlights.<ref>{{cite web |url=https://lemelson.mit.edu/resources/john-hays-hammond-jr |title=John Hays Hammond, Jr - Lemelson-MIT Program |website=lemelson.mit.edu |access-date=2017-12-13 |archive-url=https://web.archive.org/web/20170824033434/https://lemelson.mit.edu/resources/john-hays-hammond-jr |archive-date=2017-08-24 |url-status=live}}</ref> In 1922 he installed radio control gear on the obsolete US Navy battleship [[USS Iowa (BB-4)|USS ''Iowa'']] so it could be used as a [[target ship]]<ref name="Battleship4">{{cite web |url=http://www.history.navy.mil/photos/sh-usn/usnsh-i/bb4-t.htm |title=Coast Battleship No. 4 (ex-USS Iowa, Battleship # 4) -- As a Target Ship, 1921–1923 |date=13 April 2003 |work=Online Library of Selected Images:U.S. NAVY SHIPS |publisher=Naval History and Heritage Command |access-date=21 May 2012 |archive-url=https://web.archive.org/web/20100209003739/http://www.history.navy.mil/photos/sh-usn/usnsh-i/bb4-t.htm |archive-date=2010-02-09 |url-status=dead }}</ref> (sunk in gunnery exercise in March 1923).

The Soviet [[Red Army]] used remotely controlled [[teletank]]s during the 1930s in the [[Winter War]] against [[Finland]] and fielded at least two teletank battalions at the beginning of the [[Great Patriotic War]]. A teletank is controlled by radio from a control tank at a distance of 500–1500 m, the two constituting a ''telemechanical group''. There were also remotely controlled cutters and experimental remotely controlled planes in the Red Army.

The United Kingdom's World War One development of their radio-controlled 1917 'Aerial Target' (AT) and 1918 'Distant Control Boat' (DCB) using Low's control systems led eventually to their 1930s fleet of "[[de Havilland Tiger Moth|Queen Bee]]". This was a remotely controlled unmanned version of the [[de Havilland]] "[[Tiger Moth]]" aircraft for [[Navy fleet]] gunnery firing practice. The "Queen Bee" was superseded by the similarly named ''[[Airspeed Queen Wasp]]'', a purpose-built target aircraft of higher performance.

==Second World War==
Radio control was further developed during World War II, primarily by the Germans who used it in a number of [[missile]] projects. Their main effort was the development of [[radio-controlled missile]]s and [[glide bomb]]s for use against shipping, a target otherwise both difficult and dangerous to attack. However, by the end of the war, the ''[[Luftwaffe]]'' was having similar problems attacking Allied [[bomber]]s and developed a number of radio [[command guided]] [[surface-to-air anti-aircraft missile]]s, none of which saw service.

The effectiveness of the [[Luftwaffe]]'s systems, primarily comprising the series of [[Telefunken]] ''Funk-Gerät'' (or FuG) 203 ''Kehl'' twin-axis, single joystick-equipped transmitters mounted in the deploying aircraft, and Telefunken's companion FuG 230 ''Straßburg'' receiver placed in the ordnance to be controlled during deployment and used by both the [[Fritz X]] unpowered, armored anti-ship bomb and the powered [[Henschel Hs 293]] guided bomb, was greatly reduced by British efforts to jam their radio signals, eventually with American assistance. After initial successes, the British launched a number of [[commando]] raids to collect the missile radio sets. Jammers were then installed on British ships, and the weapons basically "stopped working". The German development teams then turned to [[wire-guided missiles]] once they realized what was going on, but the systems were not ready for deployment until the war had already moved to France.

The German ''[[Kriegsmarine]]'' operated ''FL-Boote'' (''ferngelenkte Sprengboote'') which were radio controlled [[motor boats]] filled with explosives to attack enemy shipping from 1944.

Both the British and US also developed radio control systems for similar tasks, to avoid the huge anti-aircraft batteries set up around German targets. However, no system proved usable in practice, and the one major US effort, ''[[Operation Aphrodite]]'', proved to be far more dangerous to its users than to the target. The American [[Azon]] guided free-fall ordnance, however, proved useful in both the [[European Theater of World War II|European]] and [[CBI Theater]]s of World War II.

Radio control systems of this era were generally electromechanical in nature, using small metal "fingers" or "[[reed receiver|reeds]]" with different [[resonant]] frequencies each of which would operate one of a number of different [[relay]]s when a particular frequency was received. The relays would in turn then activate various [[actuator]]s acting on the control surfaces of the missile. The controller's radio transmitter would transmit the different frequencies in response to the movements of a control stick; these were typically on/off signals. The radio gear used to control the rudder function on the American-developed [[Azon]] guided ordnance, however, was a fully proportional control, with the "ailerons", solely under the control of an on-board gyroscope, serving merely to keep the ordnance from rolling.

These systems were widely used until the 1960s, when the increasing use of [[solid state (electronics)|solid state]] systems greatly simplified radio control. The electromechanical systems using [[reed relay]]s were replaced by similar electronic ones, and the continued miniaturization of electronics allowed more signals, referred to as ''control channels'', to be packed into the same package. While early control systems might have two or three channels using [[amplitude modulation]], modern systems include twenty or more using [[frequency modulation]].

==Radio-controlled models==
{{Main|Radio-controlled model}}
[[File:Radiostyrning - Ystad-2019.jpg|thumb|A boy runs his radio controlled boat in [[Ystad]]'s marina 2019.]]
The first general use of radio control systems in models started in the early 1950s with single-channel self-built equipment; commercial equipment came later. The advent of [[transistor]]s greatly reduced the battery requirements, since the current requirements at low voltage were greatly reduced and the high voltage battery was eliminated. In both tube and early transistor sets the model's control surfaces were usually operated by an electromagnetic '[[Servo (radio control)#Escapements|escapement]]' controlling the stored energy in a rubber-band loop, allowing simple on/off rudder control (right, left, and neutral) and sometimes other functions such as motor speed.<ref>http://www.rcmodelswiz.co.uk/users-basic-guide-to-radio-control-systems {{Webarchive|url=https://web.archive.org/web/20150403201207/http://www.rcmodelswiz.co.uk/users-basic-guide-to-radio-control-systems |date=2015-04-03 }} RC Models Wiz: Basic Guide to Radio Control Systems.</ref>

[[Crystal oscillator|Crystal-controlled]] [[superheterodyne receiver]]s with better selectivity and stability made control equipment more capable and at lower cost. Multi-channel developments were of particular use to aircraft, which really needed a minimum of three control dimensions (yaw, pitch and motor speed), as opposed to boats, which required only two or one.

As the electronics revolution took off, single-signal channel circuit design became redundant, and instead radios provided proportionally coded signal streams which a [[servomechanism]] could interpret, using [[pulse-width modulation]] (PWM).

More recently, high-end [[hobby]] systems using [[pulse-code modulation]] (PCM) features have come on the market that provide a [[computer]]ized [[digital data]] [[bit]]-stream signal to the receiving device, instead of the earlier PWM encoding type. However, even with this coding, loss of transmission during flight has become more common{{Citation needed|date=July 2015}}, in part because of the ever more wireless society. Some more modern FM-signal receivers that still use "PWM" encoding instead can, thanks to the use of more advanced computer chips in them, be made to lock onto and use the individual signal characteristics of a particular PWM-type RC transmitter's emissions alone, ''without'' needing a special "code" transmitted along with the control information as PCM encoding has always required.

In the early 21st century, 2.4 gigahertz [[spread spectrum]] RC control systems have become increasingly utilized in control of model vehicles and aircraft. Now, these 2.4&nbsp;GHz systems are being made by most radio manufacturers. These radio systems range in price from a couple thousand [[dollar]]s, all the way down to under US$30 for some. Some manufacturers even offer conversion kits for older digital 72&nbsp;MHz or 35&nbsp;MHz receivers and radios. As the emerging multitude of 2.4&nbsp;GHz band spread spectrum RC systems usually use a "[[Frequency agility|frequency-agile]]" mode of operations, like [[Frequency-hopping spread spectrum|FHSS]] that do not stay on one set frequency any longer while in use, the older "exclusive use" provisions at model flying sites needed for VHF-band RC control systems' frequency control, for VHF-band RC systems that only used one set frequency unless serviced to change it, are not as mandatory as before.

==Modern military and aerospace applications==
{{Main|Command guidance|UAV}}
[[File:X-33 air drop model.jpg|300px|thumb|This radio-controlled [[airplane]] is carrying a scale model of [[Lockheed Martin X-33]] and is taking part in [[NASA]] research.]]
Remote control military applications are typically not radio control in the direct sense, directly operating flight control surfaces and propulsion power settings, but instead take the form of instructions sent to a completely [[Wiktionary:autonomy|autonomous]], computerized [[autopilot|automatic pilot]]. Instead of a "turn left" signal that is applied until the aircraft is flying in the right direction, the system sends a single instruction that says "fly to this point".

Some of the most outstanding examples of remote radio control of a vehicle are the  [[Mars Exploration Rover]]s such as [[Mars Pathfinder|Sojourner]].

==Industrial radio remote control==
Today radio control is used in industry for such devices as overhead [[Crane (machine)|crane]]s and switchyard [[locomotive]]s. Radio-controlled [[teleoperators]] are used for such purposes as inspections, and special vehicles for disarming of [[bomb]]s. Some remotely controlled devices are loosely called [[robot]]s, but are more properly categorized as teleoperators since they do not operate autonomously, but only under control of a human operator.

An industrial radio remote control can either be operated by a person, or by a computer control system in a [[machine to machine]] (M2M) mode. For example, an automated warehouse may use a radio-controlled crane that is operated by a computer to retrieve a particular item. Industrial radio controls for some applications, such as lifting machinery, are required to be of a fail-safe design in many jurisdictions.<ref>{{cite web|last=Autec srl|title=Radio Remote Control Safety|url=http://www.industryiq.com.au/index_htm_files/SafetyPaper2011.pdf|access-date=18 November 2013|archive-url=https://web.archive.org/web/20150310154158/http://industryiq.com.au/index_htm_files/SafetyPaper2011.pdf|archive-date=2015-03-10|url-status=live}}</ref>

Industrial remote controls work differently from most consumer products. When the receiver receives the radio signal which the transmitter sent, it checks it so that it is the correct frequency and that any security codes match. Once the verification is complete, the receiver sends an instruction to a [[relay]] which is activated. The relay activates a function in the application corresponding to the transmitters button. This could be to engage an electrical directional motor in an [[overhead crane]].
In a receiver there are usually several relays, and in something as complex as an overhead crane, perhaps up to twelve or more relays are required to control all directions. In a receiver which opens a gate, two relays are often sufficient.<ref>{{cite web|last=Tele Radio AB|title=What is industrial remote control|url=http://www.tele-radio.com/it/prodotti/what-is-industrial-remote-control/|access-date=14 November 2014|archive-url=https://web.archive.org/web/20141022021925/http://www.tele-radio.com/it/prodotti/what-is-industrial-remote-control/|archive-date=2014-10-22|url-status=live}}</ref>

Industrial remote controls are getting more and higher safety requirements. For example: a remote control may not lose the safety functionality in case of malfunction.<ref>{{Cite news|url=https://remotecontrol.help/explanation/redundant-circuits|title=Redundant circuits {{!}} Industrial remote controls|date=2016-05-03|work=Industrial remote controls|access-date=2017-06-12|language=en-US|archive-url=https://web.archive.org/web/20171227063434/https://remotecontrol.help/explanation/redundant-circuits|archive-date=2017-12-27|url-status=live}}</ref> This can be avoided by using redundant relays with forced contacts.

==See also==
* [[Precision-guided munition]]
* [[Radio-controlled airplane]]
* [[Radio-controlled boat]]
* [[Radio-controlled car]]
* [[Radio-controlled helicopter]]
* [[Remote control]]
* [[Remote control vehicle]]
* [[Telecommand]]
* [[Teletank]]

==Notes and references==
{{reflist}}

==Further reading==
{{Commons|Remote control|Radio Control}}
{{Wiktionary}}

* Bill Yenne, ''Attack of the drones: a history of unmanned aerial combat'', Zenith Imprint, 2004, {{ISBN|0-7603-1825-5}}
* Laurence R. Newcome ''Unmanned aviation: a brief history of unmanned aerial vehicles'', AIAA, 2004, {{ISBN|1-56347-644-4}},

{{Nikola Tesla|state=collapsed}}

{{Authority control}}

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