CONTROL SYSTEMSCHAPTER ONEINTRODUCTION1INTRODUCTIONContros/msacombnatonofeementsarrangednpanned manner where each eement produce desre o/p.System:Itsagroupofeementsarrangednsequenceto acheve a desred functon.S/Mscoectonofob|ects&arrangenmannertoacheveAIMor OUTPUT.s/m has /p, o/p and way to acheve ths/p-o/p combnaton.Control : It means to Reguate, Drect or Command a s/m so that desred ob|ectve s obtaned.Control system : It s arrangement of dherent physca eement connected n such a manner so as to reguate, drect or command t sef to acheve certan ob|ectvesExampes : Manufacturng process.Servomechansmnbatte-shp,spacecraft,nucearreactor,bottng pants.Guded msses, nucear power weapons.Robotcs.Prepared by : Ndh Pate2Block diagram of BASIC CONTROL S/MPrepared by : Ndh PateControsystemControsystemI/P varabe(actuatng sg.)eO/P varabe(controed varabe)CThe varabe C s to be controed by an actuatng sg e through the eements of the contro s/m.Input : The exctaton apped to contro s/m from externa source n order to produce o/p caed /p.Out put : The actua response obtaned from a s/m s caed O/P. 3Steerng mechansmSteerng mechansmPoston of steerng wheeDrecton ofsteerngwheeAn exampe s :Classifcation of control systemcontroactonsaquanttyresponsbefor actvatng the system to produce o/pControsystemmaybecassedntotwotypes dependnguponcontrolactionsdependanton status of o/p.Open oop contro systemCosed oop contro systemOpen loop control s/m : The s/m n whch contro actonstotayndependentofo/pofthes/ms caed OLCSClosedloopcontrols/m:Thes/mnwhch controactonssomehowdependentono/pofthe s/m s caed CLCS.Prepared by : Ndh Pate4Open loop control systemThereference/psappedtocontroeror amperwhoseo/psactuatngsg.,actuates contro s/m and drves contro varabe (.e o/p) The /p s no way ahected by controed o/p. /p s xed by |udgment and estmate.Change n s/m component may aso change n o/p quantty.Thedsturbancesgmaycausechangeno/p quantty.Prepared by : Ndh Pate5ControerOr AmperControerOr AmperPantPantActuatngsgControed o/pCommand OrReference sgExamples of open loop CSEectrc heatng devce wthout thermostat (.e eectrc ron and room heater)Automatc washng machne.Automatc tramc ght s/m. Eectrc hand drerBread toasterAutomatc cohee / mk serverAutomatc Eectrc ft.Gasone engnePrepared by : Ndh Pate6Advantages of open loop control s/mThe most smpestn constructon and desgnEconomcaEasy to mantan because of absence of compex eectronc crcutryProper cabraton s not a probem as the operaton of the s/m s fuy controed by human operatorThey are cheaperNot much probems of stabtyPrepared by : Ndh Pate7Disadvantage of open loop CSUsuaynaccurateandunreabe(accuracy depends on accuracy of cabraton)Thecontroad|ustmentdependsonhuman operatorhemustknewwhchgvesnaccurate resut due to atmospherc and other condton Parameter varaton uctuates the o/pThs s/m do not adapt to varaton n envronmenta condton and externa dsturbancesTheses/msaresowbecausetheynormay controed by human & he s not emcent to contro severa parameters smutaneousyOny few varabes can be ntroduced n these s/msPrepared by : Ndh Pate8Close loop control system/p command :Ths sg s generay produce by potentometer or sutaby transducer and apped to comparator.Comparator or error detector:That compares ref. sg and f/b sg and by ths error sg s produce. Error sg shows how much o/p devates from reference.Prepared by : Ndh Pate9comparatorControerControerPantPantFeed backeementFeed backeementFeed back sg.InputcommandRef.sgErrorsgActuatngsgDsturbanceControedo/pRef.TransducerRef.TransducerForward pathFeedback pathFeed back: the sg from o/ps apped to feed back n/w. ths produces the sg proportona to o/p. f/b sg fed to comparator. There shoed be -ve or +ve type feed back possbe. If f/b sg s equa to o/p then t s caed unty f/b s/m. normay t s ess then unty.Prepared by : Ndh Pate10Close loop control systemExamples of closed loop CS11Automatc eectrc ronLaunchng of guded mssesMachne too postonng etc. . .Desred tempComparsonControerO vaveFurnaceHeat sourceRoomtempHotarThermo stateActua tempError sgO suppyHome heatng s/mAccuracy s very hgh as error arsng s correctedFaster response compared to human bengSenses changes n o/p due to envronmenta dsturbences and parametrc changesUsed n hazardous and remote areas ke chemca pants, areas wth hgh nucear radaton, at very & hgh ow temperature.Decson makng s very fastReduced ehect of non-neartyMore reabe then human operator hence ed automatonNumber of varabes can be handed smutaneousy.Prepared by : Ndh Pate12Advantages of CLCSMore expensveInstaaton and ad|ustment becomes dmcutMantenance s dmcut as t nvoves compcated eectroncs and done by a traneeIf there s any faut n nstrument to fauty error sg. then no type of contro s possbe. Such a faut s dmcut and tme consumng.Prepared by : Ndh Pate13Disadvantages of CLCSComparison of OLCS & CLCSOpen loop Closed loop14No f/b is appliedNo error detectors/m is simple & requires less componentsInaccurateHigh sensitive to parameter changesMore stableDisturbance cause change in desired o/p.EconomicalSmall bandidthf/b is applied Error detector is present!omple" & requires more components#ccurate$ess sensitiveMa% become unstableDisturbance change the o/p but corrective action done & desired o/p obtained!ostl%$arge bandidthPrepared by : Ndh Pate15Servomechansmreferstothes/mwhchs manyconcernwththephyscapostonngof the oad. .e poston contro s/m.They use f/b to set the o/p to the desred eve. So they are cosed oop s/m.Exampes. Postonng of oadGun barre poston controContro of wngs and ta of ar craftPostonng of contro rods n nucear reactorsCNC machne too drvesAutomatc trackng of sateteServo mechanismGun barrel position control16In ths the gun barre s postoned n any desred drecton vewed from gun sght.It s rotated by 2 motors.Azmutha eevatonPrepared by : Ndh PateGun barrel position control17Azmuth servo: It gves command sg to azmuth comparator from the gun sghtAzmuth comparator: It compares two sgnas one from azmuth servo & other f/b sg.Azmuth amper: It ampes error sg generated by comparatorAzmuth ampdyne: t generates sumcent power to drve DC motor to poston the gun barre n azmuth drectonAzmuth f/b servo: t gves f/b sg from yhe gun barre to comparator.Smary the gun barre poston s controed n vertca. .eeevaton.Prepared by : Ndh PateAutomatic tracking of satellite18In satete communcaton s/m the antenna at ground staton has to bepostonedcorrectysoastosendsgrghttoantennaofthe satete.Prepared by : Ndh PateAc position control system19Used n the hazardous & remote areas to contro poston of oad.For ths a synchro transmtter, synchro contro transformer, an amper, 2 phase servo motor, oad are connected. Prepared by : Ndh Pate20If rotor of transmtter s shfted n poston an error votage s generated n contro transformer.Ths s amped by the amper & fed to contro wndng of 2 phase servo motor.Thus we can change poston of the oad wth hep of rotor of servo motor.When the oad shaft shfts ts poston rotor of contro transformer shfts through same ange as that of transmtter, the error become zero.Hence oad at the remote end can be postonedPrepared by : Ndh PateAc position control systemRegulators 21Reguators are cosed oop contro s/m whch are concern wth contro of a quantty.Exampes; Temperature contro of a furnaceVotage contro of generatorPressure reguaton n a vesseLqud eve contro n over head tankVotage reguaton n power suppyContro of qud ow through ppePrepared by : Ndh PateAutomatic tracking of satellite22Prepared by : Ndh PateAutomatic tracking of satellite23Prepared by : Ndh PateAutomatic tracking of satellite24Prepared by : Ndh PateAutomatic tracking of satellite25Prepared by : Ndh Pate