轮机英语（二三管轮）Lesson 29 Theory of Automatic Control.pptx

MarineEngineeringEnglish《轮机英语》APracticalCourseforEngineersWorkingonBoardShips

MarineElectricalSystemandAutomatizationLesson29BasicTheoryofAutomaticControl第29课自动控制基本理论

LearningObjectives:1.Graspsomeusefulwordsandexpressionsinthewholetext.2.Afterstudyingthelesson,heorshewillhaveabetterunderstandingofBasicTheoryofAutomaticControl.3

4part1NewWordsandExpressions

5part2TextAnalysis

L29TheoryofAutomaticControlTocontroladeviceorsystemistobeabletoadjustorvarytheparameterswhichaffectit.#对一个设备的控制就是调节或改变影响它的参数。

L29TheoryofAutomaticControlThiscanbeachievedmanuallyorautomatically,dependinguponthearrangementsmadeinthesystem.#这可由手动实现，也可自动完成，取决于系统的布置。

L29TheoryofAutomaticControlAllformsofcontrolcanbeconsideredtoactinaloop.#所有控制形式可看作在一回路发生作用。

L29TheoryofAutomaticControlThebasicelementspresentintheloopareadetector,acomparatorandaregulator,allofwhichsurroundtheprocessandformtheloop.#组成回路的基本元件是传感器，比较器和调节器，它们均围绕处理过程，组成控制回路(图29-a)。

L29TheoryofAutomaticControlThisarrangementisanautomaticclosedloopiftheelementsaredirectlyconnectedtooneanotherandthecontrolactiontakesplacewithouthumaninvolvement.#若各元件依次相连，则组成自动闭环控制，控制作用无人干预。

L29TheoryofAutomaticControlAmanualclosedloopwouldexistifoneelementwerereplacedbyahumanoperator.如某一元件由人工代替，则为手动闭环控制。

L29TheoryofAutomaticControlItcanbeseenthereforethatinaclosedloopcontrolsystemthecontrolactionisdependentontheoutput.#由此可见，在闭环控制系统中，控制作用依赖于系统输出。

L29TheoryofAutomaticControlAdetectingormeasuringclementwillobtainasignalrelatedtothisoutputwhichisfedbacktothetransmitter.Fromthetransmitterthesignalisthenpassedtoacomparator.#检测元件或测量元件能获得与输出有关的信号，该信号传给变送器，之后传送到比较器。

L29TheoryofAutomaticControlThecomparatorwillcontainsomesetordesiredvalueofthecontrolledconditionwhichiscompared