human factors engineering ppp zhrp 1e

8/8/2019 Human Factors Engineering Ppp Zhrp 1e

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Human Factors EngineeringHuman Factors Engineering


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HumanHuman FactorsFactors EngineeringEngineering embracesembraces aa broadbroad approach,approach,focusfocus uponupon mansmans sensorysensory input,input, motormotor responseresponse output,output,

andand informationinformation processingprocessing characteristicscharacteristics andand theirtheirinteractioninteraction withwith environmentalenvironmental conditionsconditions andand systemsystemfunctionfunction requirementsrequirements..

HumanHuman FactorsFactors EngineersEngineers tasktask isis toto definedefine humanhuman

performanceperformance requirementsrequirements andand ensureensure thatthat thesethese areare notnotcompromisedcompromised byby improperimproper equipmentequipment designdesign andand layoutlayout..

IndustrialIndustrial EngineeringEngineering concernedconcerned withwith thethe relationrelationbetweenbetween men,men, machines,machines, andand materials,materials, andand

accordinglyaccordingly hashas evolvedevolved effectiveeffective methodologymethodology forfordealingdealing withwith thethe problemsproblems ofof operatoroperator efficiencyefficiencyandand workplaceworkplace layoutlayout..


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Human Factors Engineering Topics:Human Factors Engineering Topics:

1.1. display and control designdisplay and control design

2.2. human physical characteristicshuman physical characteristics

3.3. environmental factorsenvironmental factors

4.4. design for maintenancedesign for maintenance

**othersothers

injury controlinjury control

product designproduct design

misconception regarding fatiguemisconception regarding fatigue

and environmental stressand environmental stress


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THE HUMAN FACTORS ENGINEERING APPROACHTHE HUMAN FACTORS ENGINEERING APPROACH

CharacteristicsCharacteristics ofof thethe FieldField.. TheThe humanhuman factorsfactorsengineeringengineering fieldfield characterizedcharacterized byby concernconcern withwith thetheefficientefficient andand safesafe utilizationutilization ofof manman inin manman--machinemachinesystems,systems, soso asas toto taketake intointo accountaccount bothboth mansmans capabilitiescapabilities

andand hishis limitationslimitations..

ContrastContrast withwith IndustrialIndustrial EngineeringEngineering.. AA distinctivedistinctive aspectaspect ofofthethe fieldfield involvesinvolves thethe vastvast interdisciplinaryinterdisciplinary bodybody ofof

knowledgeknowledge andand methodologiesmethodologies consideredconsidered byby humanhumanfactorsfactors specialistsspecialists inin hishis approachapproach toto manman--machinemachine systemssystemsproblemsproblems..


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EducationEducation andand th ethe CommunicationCommunication GapGap.. AlthoughAlthoughpsychologistspsychologists havehave beenbeen aa dominantdominant forceforce ofofthethe humanhumanfactorsfactors thethe challengeschallenges ofof thethe fieldfield demanddemand aa departuredeparturefromfrom traditionaltraditional trainingtraining inin psychologypsychology asas wellwell asas ininindustrialindustrial engineeringengineering..

HistoryHistory ofof thethe fieldfield.. HistoryHistory providesprovides manymany examplesexamples wherewhere

littlelittle attentionattention hashas beenbeen givengiven duringduring systemssystemsdevelopmentdevelopment toto humanhuman functionsfunctions andand requirementsrequirements..

TypicalTypical humanhumanerrorerror tracetrace toto::

1.1. failurefailure onon thethe partpart ofofthethe designdesign engineersengineers toto con siderconsiderhumanhuman limitationslimitations..

2.2. placingplacing tootoo muchmuch ofofaa demanddemand uponupon thethe operatoroperator..

3.3. poorpoor oror improperimproper equipmentequipment designdesign andand layoutlayout..


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TheThe SystemsSystems ConceptConcept.. WhenWhen aa humanhuman factorsfactors engineerengineertalkstalks ofof systems,systems, generallygenerally meansmeans manman--machinemachine systemssystems..SuchSuch systemssystems cancan varyvary inin sizesize andand complexitycomplexity..

RolesRoles ofof thethe HumanHuman FactorsFactors EngineerEngineer.. TheThe specialtyspecialty ofof thethehumanhuman factorsfactors engineerengineer isis hishis approachapproach toto manman--machinemachinesystemsystem design,design, developmentdevelopment ,, andand evaluationevaluation.. ThiThi99ss

approachapproach putsputs primeprime emphasisemphasis onon analysisanalysis andand allocationallocationofof systemsystem functionfunction toto ensureensure thethe effectiveeffective useuse ofof manmanmeetingmeeting systemsystem requirementsrequirements..

ManMan asas aa systemsystem ElementElement.. ToTo considerconsider humanhuman performanceperformance inin

properproper perspective,perspective, itit isis firstfirst necessarynecessary toto understandunderstandexactlyexactly howhow manman relatesrelates toto andand interactsinteracts withwith otherother systemsystemelementselements..


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Determinants of Systems Performance:Determinants of Systems Performance:A.A. Personnel capabilityPersonnel capability

1.1. SelectionSelection

a.a. Ability, experienceAbility, experienceb.b. Personality, attitude, interestPersonality, attitude, interestc.c. Physical characteristicsPhysical characteristics

2.2. TrainingTraining

B.B. The systemThe system1.1. DesignDesigna.a. Equipment design, displays, and controlsEquipment design, displays, and controlsb.b. Workplace layoutWorkplace layoutc.c. Job aids, tool designJob aids, tool design

d.d. Environmental considerationsEnvironmental considerations2.2. OperationOperation

a.a. Work loadWork loadb.b. Communication channelsCommunication channelsc.c. MaintainabilityMaintainability


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C.C. Modifiers of contextModifiers of context

1.1. SupervisionSupervision

2.2. Administrative procedures, policy; rules, lawsAdministrative procedures, policy; rules, laws

3.3. Health and moraleHealth and morale

a.a. Drugs, diet, sleepDrugs, diet, sleep

b.b. Family problems as source mental distractionFamily problems as source mental distraction

4.4. Work schedule and rotationWork schedule and rotation

5.5. Unusual environmental stressUnusual environmental stress


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THE SYSTEMS DEVELOPMENT CYCLETHE SYSTEMS DEVELOPMENT CYCLE

UnderstandingUnderstanding ofof thethe conceptconcept ofof thethe systemssystemsdevelopmentdevelopment cyclecycle isis aa corecore requirementrequirement forfor thethe humanhumanfactorsfactors engineerengineer.. Although Although itit isis recognizedrecognized thatthat fewfew

IndustrialIndustrial engineerengineer commonlycommonly playplay thethe rolerole ofof thethe humanhumanfactorsfactors protagonistprotagonist inin thethe systemsystem development,development,nonetheless,nonetheless, whenwhen aa newnew manufacturingmanufacturing plantplant ororproductionproduction systemsystem isis regardedregarded asas aa manman--machinemachinesystem,system, thethe conceptconcept hashas directdirect relevancerelevance toto thethe engineerengineerinvolvedinvolved inin plantplant designdesign andand layoutlayout..


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HumanHuman PerformancePerformance RequirementsRequirements.. TheThe identificationidentificationandand analysisanalysis ofof humanhuman performanceperformance requirementsrequirements beginbegininin thethe predesignpredesign stagestage ofof thethe systemsystem developmentdevelopment cyclecycleandand continuecontinue intointo developmentdevelopment stagestage..

Three phases of application are associate with theThree phases of application are associate with theanalysis activity:analysis activity:

I.I. FunctionFunction AnalysisAnalysis.. TheThe factionfaction analysisanalysis phasephase beginsbeginswithwith thethe criticalcritical assessmentassessment ofof thethe factionsfactions toto bebeperformedperformed byby thethe systemsystem.. TheThe goalgoal isis toto allocateallocate

functionsfunctions toto man,man, machine,machine, oror manman--machinemachinecombinationscombinations soso asas toto optimizeoptimize overalloverall systemssystems

efficiencyefficiency..


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StepsSteps ofof functionfunction analysisanalysis

11stst stepstep:: functionfunction allocation,allocation, informationinformation onon systemsystemoperationaloperational requirementsrequirements isis requiredrequired..

22ndnd

stepstep:: operationaloperational requirementsrequirements areare brokenbroken downdown intointofunctionfunction systemsystem thatthat isis capabilitiescapabilities forfor convertingconverting inputsinputs totooutputsoutputs..

FinalFinal stepstep:: assignmentassignment ofof functionfunction toto menmen andand equipmentequipment..


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WhichWhich functionfunction areare performedperformed betterbetter byby manman oror byby machine?machine?TheThe followingfollowing generalizationsgeneralizations cancan bebe serveserve guideguide..

ManMan isis betterbetter andand uniqueunique::

1.1. AtAt discriminatingdiscriminating relevantrelevant fromfrom irrelevantirrelevant signalssignals

2.2. AtAt innovationinnovation andand problemproblem solvingsolving

3.3. InIn reasoningreasoning inductivityinductivity

4.4. InIn perceivingperceiving patternspatterns andand generalizinggeneralizing aboutabout themthem

5.5. InIn profitingprofiting andand experienceexperience

6.6. InIn abilityability toto selectselect hishis ownown inputsinputs

7.7. InIn improvising,improvising, adoptingadopting flexibleflexible procedures,procedures, andand

exercisingexercising judgmentjudgment basedbased onon minimalminimal informationinformation8.8. InIn beingbeing sensitivesensitive toto aa widewide varietyvariety ofof stimulistimuli

9.9. InIn selectiveselective recallrecall ofof oldold informationinformation


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MachinesMachines areare betterbetter oror areare uniqueunique::

1.1. ForFor routineroutine processingprocessing andand storagestorage ofof largelarge amountsamounts ofof

factsfacts andand detailsdetails2.2. ForFor exertingexerting greatgreat force,force, smoothlysmoothly andand preciselyprecisely

3.3. ForFor monitoringmonitoring manman andand machinemachine

4.4. ForFor repetitiverepetitive andand preciseprecise operationsoperations

5.5. In operating under conditions that are stressful orIn operating under conditions that are stressful orintolerable to manintolerable to man

6.6. For rapid response to signalsFor rapid response to signals

7.7. For rapid recall of large amounts of dataFor rapid recall of large amounts of data

8.8. For accurate, rapid, and complex computationsFor accurate, rapid, and complex computations9.9. For originating and sustaining many actions concurrentlyFor originating and sustaining many actions concurrently

10.10. In sensing stimuli beyondIn sensing stimuli beyond the range of human sensitivitythe range of human sensitivity


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II.II. TaskTask DerivationDerivation.. TaskTask derivationderivation beginsbegins wherewhere thethefunctionfunction a llocationallocation phasephase endsends.. FunctionFunction toto bebe

performedperformed byby manman areare consideredconsidered inin relationrelation toto thetheequipmentequipment whichwhich hehe willwill work,work, thethe goalgoal herehere beingbeing thetheidentificationidentification ofof specificspecific elementselements ofof behaviorbehavior requiredrequiredinin thethe operationaloperational contextcontext..

III.III. TaskTask andand SkillSkill AnalysisAnalysis.. TheThe finalfinal phasephase ofofthethe activityactivity inindeterminingdetermining humanhuman performanceperformance requirementsrequirements isis tasktaskandand skillskill analysisanalysis.. TheThe goalgoal herehere isis aa comprehensivecomprehensivedelineationdelineation o fof thethe physicalphysical andand physiologicalphysiological

characteristicscharacteristics requiredrequired byby allall thethe systemsystem tasks,tasks, withwithaccompanyingaccompanying specificationspecification ofof thethe levelslevels ofof KnowledgeKnowledgerequiredrequired..


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EquipmentEquipment DesignDesign.. CollaborationCollaboration withwith designdesign engineersengineers ininthethe designdesign andand layoutlayout ofof equipmentequipment isis thethe secondsecond majormajor

areaarea ofof humanhuman factorfactor responsibilityresponsibility.. ConsiderationConsideration maymayincludeinclude displaydisplay ofof informationinformation neededneeded forfor decisiondecision andandresponse,response, selectionselection controlcontrol forfor effectiveeffective action,action, provisionprovision ofofnecessarynecessary jobjob aids,aids, efficientefficient layoutlayout ofof thethe workplace,workplace, andanddesigndesign forfor maintainabilitymaintainability..

DesignDesign TradeTrade--offsoffs.. AsAs tentativetentative designdesign areare proposed,proposed, theretherewillwill bebe inevitableinevitable conflictsconflicts inin tryingtrying toto satisfysatisfy bothboth humanhumanfactorsfactors andand engineersengineers designdesign criteriacriteria..

UndesirableUndesirable DesignDesign CharacteristicsCharacteristics.. AnalysisAnalysis ofof accidentaccident data,data,casecase studies,studies, andand laboratorylaboratory researchresearch hashas identifiedidentified certaincertainpracticespractices whichwhich increaseincrease probabilityprobability ofof humanhuman errorerror ororefficiencyefficiency..


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DetectionDetection of of ErrorError--producingproducing DesignDesign.. SeveralSeveral techniquestechniques oror

aidsaids forfor identifyingidentifying errorerror--producingproducing designdesign areare availableavailableandand areare discusseddiscussed inin greatergreater detaildetail suchsuch referencereference asasChapanisChapanis ororMeisterMeisterandandRabideauRabideau..

JobJob AidsAids.. Manuals,Manuals, checklists,checklists, handbooks,handbooks, charts,charts, andand

troubleshootingtroubleshooting guidesguides areare classedclassed asas jobjob aidsaids whenwhen theytheyusedused toto facilitatefacilitate tasktask performanceperformance andand reducereduce thethe burdenburdenononanan operator'soperator'smemorymemory andand decisiondecisionmakingmakingabilitiesabilities..

EnvironmentalEnvironmental ConsiderationsConsiderations.. As As t askstasks andand equipmentequipment

becomebecome specifiedspecified inin thethe developmentdevelopment cycle,cycle, attentionattentionshouldshouldbebe givengiven environmentalenvironmental factorsfactors thatthat relaterelate toto safety,safety,comfortcomfortandand performanceperformance..


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PersonnelPersonnel SubsystemsSubsystems.. TheThe personnelpersonnel subsystemsubsystem conceptconceptimpliesimplies concurrentconcurrent attentionattention toto equipmentequipment designdesign andand toto

thethe personnelpersonnel thatthat willwill operateoperate equipmentequipment.. OtherOther aspectsaspectsofof thethe personnelpersonnel subsystemssubsystems programprogram includeinclude developmentdevelopmentofof trainingtraining aidsaids andand devicesdevices andand ofof thethe proficiencyproficiency teststestschecklistschecklists forfor useuse inin apprisingapprising performanceperformance ofof thethe systemsystemonceonce itit isis operationaloperational..

DISPLAY AND DESIGN AND SELECTIONDISPLAY AND DESIGN AND SELECTION

DisplaysDisplays areare necessarynecessary extensionsextensions toto mansmans sensesense andandprovideprovide bothboth supplementalsupplemental andand primeprime informationinformation neededneededbyby humanhuman operatorsoperators inin makingmaking decisiondecision andand effectingeffectingcontrolcontrol responseresponse..


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GeneralGeneral GuidelinesGuidelines.. AA basicbasic rulerule inin displaydisplay designdesign isis totopresentpresent onlyonly thatthat thethe informationinformation neededneeded byby operatoroperator toto

makemake decisiondecision responseresponse andand nono moremore..

ConditionCondition useuse.. TheThe distancedistance andand positionposition ofof thethe operatoroperatorrelativerelative toto thethe displaydisplay areare importantimportant considerationconsideration.. OptimalOptimal

viewingviewing distancedistance forfor printedprinted materialsmaterials isis typicallytypicallyconsideredconsidered aboutabout 1616 inches,inches, whilewhile forfor cathodecathode rayray tubestubesrangerange ofof 1414 toto 1818 inchesinches isis acceptableacceptable.. TheThe preferredpreferred angleangleviewview isis 9090 degreesdegrees toto thethe planeplane displays,displays, 6060 degreesdegrees forforseatedseated andand forfor alternatesalternates sittingsitting andand standingstanding 4545 degreesdegrees..

DependingDepending onon thethe angleangle viewview andand onon installationinstallation practices,practices,glassglass coverscovers onon displaysdisplays cancan bebe sourcesource ofof problemsproblemsinvolvinginvolving glare,glare, shadows,shadows, andand parallaxparallax..


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TypesTypes ofof DisplaysDisplays.. ThereThere areare variousvarious waysways toto categorizedcategorizeddisplaysdisplays inin termsterms ofof theirtheir purposepurpose andand useuse.. SignsSigns andandlabelslabels are,are, inin effect,effect, displaysdisplays of of aa staticstatic varietyvariety.. MostMost

displaysdisplays areare symbolicsymbolic inin thatthat theythey areare anan abstractabstractrepresentationrepresentation systemsystem conditionsconditions (rpm,(rpm, pressure,pressure,temperature)temperature) oror parametersparameters relatedrelated toto performanceperformance(altitude,(altitude, distance)distance)..

VisualVisual DisplayDisplay DesignDesign FactorsFactors.. RelatedRelated toto eacheach ofof thetheusersusers andand typestypes ofofdisplaysdisplays..

MechanicalMechanical IndicatorsIndicators.. SymbolicSymbolic indicationindication areare 33 basicbasic typestypes ::

a.a. TheThe directdirect--readingreading countercounter

b.b. TheThe movingmoving pointerpointer--fixedfixed scalescale

c.c. FixedFixed pointerpointer--movingmoving scalescale


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DigitalDigital ReadoutsReadouts.. VariousVarious kindskinds ofof digitaldigital readoutsreadouts arearecommonlycommonly foundfound inin electronicelectronic equipment,equipment, suchsuch asas digitaldigital

voltmetersvoltmeters andandhighhigh--speedspeedcounterscounters.. TheseThese includeinclude decimaldecimalarrays,arrays, matrixmatrix displays,displays, registerregister tubestubes (the(the soso--calledcalled NixieNixiereadout),readout), edgeedge lightedlightedplates,plates, andand rearrear--projectorprojector devicesdevices..

PictorialPictorial a ndand Cat hodeCathode RayRay TubeTube DisplaysDisplays.. ForFor industrialindustrial

applicationapplication ,, carecare shouldshould bebe exercisedexercised inin selectingselecting thosethoseportionsportions ofof aa pictorialpictorial displaysdisplays thatthat constituteconstitute referencereferenceandand thosethose thatthat representrepresent movementmovement.. CathodeCathode rayray tubestubeshavehave commoncommon applicationapplication inin radar,radar, sonar,sonar, navigation,navigation,electronicelectronic testing,testing, andandmonitoringmonitoring..

IndicatorIndicator Lights,Lights, Signals,Signals, andand WarningWarning DevicesDevices.. LightsLights andandmechanicalmechanical flagflag signalsignal areare usefuluseful toto indicateindicate statusstatus ofofsystemsystem oror totoprovideprovide cautionscautions andandwarningswarnings..


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The principal design requirements here involve:The principal design requirements here involve:

1.1. getting the attention of the operator.getting the attention of the operator.2.2. telling him what his wrong or what should do.telling him what his wrong or what should do.

LabelsLabels.. GoodGood labelslabels areare aa necessarynecessary additionaddition forfor displaysdisplays

identificationidentification andand interpretationinterpretation.. LabelsLabels shouldshould bebe placedplacedhorizontalhorizontal toto thethe limelime sightsight ,, closeclose toto thethe componentcomponent beingbeingidentified,identified, andand indicateindicate parametersparameters measuredmeasured ratherrather thanthanthethe typetype ofof instrumentinstrument.. ClarityClarity andand brevitybrevity ofof wordingwording areare

essentialessential.. Manufacture'sManufacture's andand tradetrade namesnames shouldshould avoidedavoidedonon instrumentinstrument facesfaces.. LabelsLabels forfor aa numbernumber ofof groupedgroupeddisplaysdisplays shouldshould bebe arrangedarranged consistentlyconsistently (preferably(preferably above)above)andand inin anan orderly,orderly, logicallogical patternpattern asas shouldshould displaydisplaythemselvesthemselves..


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** OtherOther generalgeneral recommendationsrecommendations::

1.1. useuse allall capitalcapital lettersletters

2.2. avoidavoid abbreviationsabbreviations

3.3. letterletter widthwidth--toto--heightheight ratioratio shouldshould bebe 33 toto 55

4.4. strokestroke widthwidth shouldshould bebe aboutabout 11//88 charactercharacter heightheight

5.5. forfor 2828--inchinch panelpanel distancesdistances oror less,less, letterletter heightheight shouldshouldbebe atat leastleast 00..2020 inchinch

6.6. printprint shouldshould bebe blackblack onon whitewhite mattematte background,background, exceptexcept

forfor situationsituation wherewhere lowlow levelslevels ofof illuminationillumination obtain,obtain, andandthenthen thethe relationrelation shouldshould reversedreversed..


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AuditoryAuditory SignalsSignals.. ConsiderationConsideration isis oftenoften givengiven toto thethe useuse ofofauditoryauditory displaysdisplays::

1.1. whenwhen thethe visualvisual channelchannel isis overloadedoverloaded

2.2. whenwhen illuminationillumination oror vibrationvibration levelslevels areare suchsuch asas totoprecludepreclude optimaloptimal useuse ofof aa visualvisual displaydisplay

3.3. asas anan alertingalerting cuecue oror warningwarning devicedevice

** AuditoryAuditory warningswarnings shouldshould bebe atat leastleast 1010 decibelsdecibels aboveabovethethe ambientambient noisenoise levellevel.. TheyThey alsoalso usefuluseful toto indicateindicate offoff--

coursecourse oror outout--ofof--tolerancetolerance conditionsconditions inin operatoroperator trackingtrackingtasktask..

** Buzzers,Buzzers, bells,bells, chimes,chimes, sirens,sirens, hornshorns allall havehave specificspecific

warningwarning devicesdevices..


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CharacteristicsCharacteristics toto considerconsider includeinclude thethe followingfollowing::

1.1. forfor distancedistance overover 11,,000000 feet,feet, useuse44 highhigh--intensityintensity signalssignalslessless thanthan 11,,000000 cyclescycles perper secondsecond

2.2. IfIf obstaclesobstacles oror portionsportions intervene,intervene, keepkeep frequenciesfrequencies

belowbelow 500500 cyclescycles perper secondsecond3.3. ToTo demanddemand attentionattention ,, useuse intermittentintermittent beepsbeeps oror warblingwarbling

soundssounds varyingvarying inin frequencyfrequency

4.4. ChooseChoose signalsignal frequenciesfrequencies toto optimizeoptimize differencesdifferences fromfrompossiblepossible makingmaking noisesnoises


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CONTROLCONTROL DESIGNDESIGN ANDAND SELECTIONSELECTION

The selection of controls should be considered withregard to the functional requirements of the system. Theamount of informational detail presented in a displaycommonly predetermines the choice of a control.Additional functional requirements that add refinement to

control specifications include:

1. the amount of force required by the response

2. the speed and precision of operation required

3. desirable feedback to the operator concerning theresult of his action


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Design Factors.Design Factors. The following discussion applies to controlsThe following discussion applies to controls

generally .although specific controls will receive somegenerally .although specific controls will receive somemention for purposes of illustration.mention for purposes of illustration.

ControlControl--DisplayDisplay CompatibilityCompatibility.. A A basicbasic rulerule inin panelpanel ororworkplaceworkplace layoutlayout isis toto makemake thethe relationsrelations betweenbetween displaysdisplaysandand theirtheir associatedassociated controlcontrol logicallogical andand clearclear--cutcut.. TheThe

problemproblem ofof habithabit interferenceinterference isis broughtbrought aboutabout ((11))violationsviolations ofof populationpopulation stereotypesstereotypes oror ((22)) lacklack ofofstandardizationstandardization inin taskstasks whichwhich operatorsoperators encounterencounter inin moremorethanthan oneone situationsituation..

ControlControl--displaydisplay RatiosRatios.. TheThe ratioratio ofof thethe distancedistance ofof controlcontrolmovementmovement toto thatthat ofof thethe movingmoving elementelement ofof thethe displaydisplay orortoto movementmovement ofof aa vehiclevehicle underunder controlcontrol isis calledcalled thethecontrolcontrol--displaydisplay ratioratio..


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ControlControl ResistanceResistance andand F eedbackFeedback.. ResistanceResistance inin controlcontroloperationsoperations inin aa criticalcritical variablevariable because,because, itit cancan affectaffect aanumbernumber ofof factors,factors, includingincluding ((11)) thethe feedbackfeedback toto thetheoperatoroperator regardingregarding controlcontrol positionposition;; ((22)) thethe speed,speed,precision,precision, andand smoothnesssmoothness ofof controlcontrol operationoperation;; ((33)) thethesusceptibilitysusceptibility ofof thethe controlcontrol toto accidentaccident activationactivation andandvariationvariation..

AccidentAccident ActivationActivation.. CriticalCritical controlscontrols cancan bebe isolatedisolated ororarrangedarranged inin aa sequencesequence thatthat tendstends toto precludepreclude accidentalaccidentaloperationoperation..

ControlControl CodingCoding.. OperationOperation ofofthethe wrongwrong controlcontrol atat timestimes cancanbebe frustratingfrustrating ,, leadlead inefficiency,inefficiency, oror causecause accidentsaccidents..


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ChoiceChoice ofof codescodes cancan bebe affectedaffected byby suchsuch variablesvariables asas thethenumbernumber ofof controlscontrols toto bebe coded,coded, availableavailable panelpanel space,space,levellevel andand qualityquality ofof illumination,illumination, operatoroperator workwork load,load, thethe

criticallycritically ofof controlcontrol function,function, andand whetherwhether codingcoding hashasbeenbeen usedused forfor otherother purposespurposes (safety(safety codescodes oror displaydisplay orortargettarget identification)identification)..

SpecificSpecific ControlControl RecommendationsRecommendations.. Various Various functionalfunctional

requirementsrequirements andand designdesign featuresfeatures areare summarizedsummarized herehereforfor specificspecific controlscontrols areare followsfollows::

1.1. PushPush buttonsbuttons shouldshould havehave positive,positive, snapsnap (click)(click) actionaction forforoperatoroperator feedbackfeedback andand concaveconcave oror roughrough surfacesurface topstops toto

aidaid inin fingeringfingering..2.2. RockerRocker keyskeys provideprovide desirabledesirable visualvisual feedbackfeedback ofof theirtheir

state,state, butbut inin horizontalhorizontal layoutslayouts areare proneprone toto inadvertentinadvertentoperationoperation..


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3.3. ToggleToggle switchesswitches provideprovide aa quickquick modemode response,response, requirerequirelittlelittle space,space, andand cancan bebe operatedoperated simultaneouslysimultaneously withwithothersothers inin thethe bankbank..

4.4. RotaryRotary selectorselector switchesswitches requirerequire aa mediummedium amountamount ofofspacespace andand cancan givegive goodgood visualvisual andand tactualtactual feedbackfeedback ofofposition,position, butbut requirerequire aa tradetrade--ofof speedspeed andand accuracyaccuracy ififmanymany sittingssittings requiredrequired..

5.5. SlideSlide switchesswitches andand thumbthumb--wheelswheels havehave limitedlimited useuse;; forforeaseease ofof operationsoperations serrationsserrations areare recommendedrecommended..

6.6. KnobsKnobs forfor continuouscontinuous controlcontrol cancan bebe shape,shape, andand colorcolorcodedcoded effectively,effectively, andand withwith appropriateappropriate gearing,gearing, provideprovide

aa considerablyconsiderably flexibleflexible choicechoice ofof adjustmentsadjustments..7.7. CranksCranks areare usedused forfor highhigh ratesrates ofof adjustmentadjustment overover longlong

distancesdistances.. PositionPosition feedbackfeedback isis poorpoor.. TheyThey areare generallygenerallyamenableamenable toto codingcoding..


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8.8. LeversLevers areare commonlycommonly usedused asas geargear shifts,shifts, throttles,throttles, ororjoysticksjoysticks inin positioningpositioning oror trackingtracking tasktask..

9.9. SteeringSteering (hand)(hand) wheelswheels areare usefuluseful wherewhere largelarge rotaryrotaryforcesforces mustmust bebe applied,applied, butbut theythey demanddemand aa spacespacepenaltypenalty..

10.10. PedalsPedals havehave characteristicscharacteristics similarsimilar toto handwheelshandwheels goodgoodforfor largelarge forceforce applications,applications, poorpoor inin termsterms ofof spacespace utilityutility..

WORKSPACEWORKSPACE LAYOUTLAYOUT

TheThe effectiveeffective layoutlayout workplaceworkplace isis basedbased onon manymanyconsiderations,considerations, includingincluding thethe naturenature ofof thethe taskstasks (speed(speed

andand accuracyaccuracy requirements,requirements, loadload sequence,sequence, efforteffortcritically),critically), allowableallowable systemsystem tolerance,tolerance, informationinformation input,input,responseresponse outputs,outputs, environmentalenvironmental conditions,conditions, equipmentequipmentspecification,specification, andand maintenancemaintenance requirementsrequirements..


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PrinciplePrinciple ArrangementArrangement.. InIn thethe contextcontext ofof industrialindustrial plantplantlayoutlayout ,, thethe industrialindustrial engineerengineer willwill havehave evaluatedevaluated spacespace

allocations,allocations, utilizingutilizing flowflow chartscharts ofof materialmaterial equipment,equipment,people,people, andand operationsoperations..

LinksLinks AnalysisAnalysis.. AA valuablevaluable techniquetechnique forfor determiningdetermining thethefrequencyfrequency andand importanceimportance ofof interactionsinteractions betweenbetween menmenandand machinesmachines soso asas toto developdevelop efficientefficient workspaceworkspacearrangementarrangement..

ProceduresProcedures::

1.1. ConstructConstruct aa roughrough diagramdiagram usingusing circlescircles labeledlabeled withwithnumbersnumbers toto identifyidentify operatoroperator functions,functions, andand squaressquareslabeledlabeled withwith lettersletters toto identifyidentify equipmentequipment..


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2.2. DeterminingDetermining andand identifyingidentifying separately,separately, throughthrough codedcodedline,line, thethe variousvarious control,control, visual,visual, andand talktalk linkslinks betweenbetween allallcombinationcombination elements,elements, thatthat isis manman--man,man, machinemachine--machine,machine, andand manman--machinemachine..

3.3. UsingUsing thethe threethree--pointpoint scale,scale, havehave expertsexperts weightweight eacheachlinklink inin termsterms ofof bothboth frequencyfrequency andand importanceimportance ofof useuse..

4.4. MultiplyMultiply thethe twotwo weightingsweightings forfor eacheach links,links, andand thenthen listlist

allall componentscomponents inin rankrank orderorder accordingaccording toto thethe sumsum ofoftheirtheir compositecomposite linklink ratingsratings..

5.5. RedrawRedraw thethe originaloriginal diagramdiagram soso thatthat thethe linkslinks withwith higherhighercompositescomposites ratingsratings areare shortershorter thanthan thosethose whowho withwith

lowerlower ratings,ratings, andand trytry toto reducereduce crossingcrossing linkslinks..6.6. ModifyModify thethe drawingdrawing inin accordanceaccordance withwith thethe systemsystem

constrain,constrain, includingincluding physicalphysical accessaccess toto controlscontrols ,, fieldfield ofofvision,vision, communicationcommunication efficiency,efficiency, andand indicesindices ofof walkingwalkingandand crowdingcrowding..


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WorkplaceWorkplace ArrangementArrangement CriteriaCriteria.. AttentionAttention isis thethe nextnext focusedfocusedonon thethe individualindividual operatoroperatorstationsstations..

SeveralSeveral principles,principles, oror criteria,criteria, toto taketake intointo accountaccount areare asasfollowsfollows::

1.1. GroupGroup togethertogether componentscomponents ofof similarsimilar functionfunction..

2.2. PlacePlace importantimportant oror criticalcritical controlscontrols inin thethe bestbest locationlocation forfor

rapidrapid andand earlyearly useuse..3.3. ArrangeArrange componentscomponents operatedoperated oror viewedviewed inin sequencesequence inin

closeclose andand logicallogical physicalphysical relationshipsrelationships..

4.4. PlacePlace componentscomponents usedused mostmost frequentlyfrequently inin centralcentrallocations,locations, andand thosethose infrequentlyinfrequently usedused inin peripheralperipheral

areasareas..5.5. RecognizedRecognized areare certaincertain controlscontrols requiredrequired optimumoptimum

locationslocations inin termsterms ofof reactionreaction time,time, accuracy,accuracy, ofof forceforcethatthat mustmustbebe appliedapplied..


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AnalyticalTechniques.AnalyticalTechniques. Task analyses previouslyperformedTask analyses previouslyperformedcanprovide usefulinformationaboutinformationdisplay,canprovide usefulinformationaboutinformationdisplay,controlresponse, and communication requirementsatcontrolresponse, and communication requirementsat

individualwork station.individualwork station.

Display,Display, Controls,Controls, andand PanelPanel LayoutLayout.. TheThe problemsproblems ofof habithabitinterferenceinterference andand compatibilitycompatibility discusseddiscussed earlierearlier areare

accentuatedaccentuated whenwhen controlscontrols andand displaysdisplaysmustmustbebe integratedintegratedwithinwithin thethe largerlarger contextcontextofof panelpanel layoutlayout..

OtherOther DesignDesign ConsiderationsConsiderations.. StandardStandard humanhuman factorsfactors guidesguides

includeinclude thethe datadata onon thethe designdesign ofof aislesaisles andand corridors,corridors,doorways,doorways, hatches,hatches, ladders,ladders, stairs,stairs, ramps,ramps, workwork platform,platform,andand specialspecial chairschairs andand tablestables.. RelatedRelated toto eacheach ofof thesetheseapplicationapplication isis needneed toto considerconsider humanhuman bodybody size,size, structure,structure,andand physicalphysicalmovementmovement..


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Anthropometric Anthropometric FactorsFactors.. FailureFailure toto taketake intointo accountaccounthumanhuman bodybody measurementsmeasurements asas characteristicscharacteristics inin workplaceworkplace

layoutlayout cancan havehave adverseadverse effectseffects onon operatoroperator efficiency,efficiency,health,health, andand wellwell--beingbeing..

StaticStatic AnthropometryAnthropometry.. ItIt mustmust bebe recognizedrecognized thatthat therethere isis nonosuchsuch thingthing asas anan averageaverage manman.. AA personperson averageaverage isis oneonedimensiondimension maymay bebe farfar fromfrom averageaverage inin another,another, andand thusthus ititisis virtuallyvirtually impossibleimpossible toto designdesign forfor allall extremesextremes ofof aaworkplaceworkplace layoutlayout problemsproblems.. AnthropometricAnthropometric datadata arearefurtherfurther usefuluseful inin thethe designdesign ofof personalpersonal equipmentequipment

(helmets,(helmets, goggles,goggles, masks,masks, earphones,earphones, gloves),gloves), escapeescapehatches,hatches, worktablesworktables andand desks,desks, vehicles,vehicles, prosthetic,prosthetic,devices,devices, furniture,furniture, appliances,appliances, officeoffice equipment,equipment, andandpassengerpassenger seatsseats..


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DynamicDynamic AnthropometryAnthropometry.. ConcernedConcerned withwith thethe functionalfunctional rangerangeandand thethe patternpattern ofof thethe bodybody movementsmovements andand withwith thetheoperationsoperations thatthat cancan bebe mademade byby thethe limbslimbs inin variousvariouspositionspositions.. DynamicDynamic datadata forfor kneeling,kneeling, crawling,crawling, andand pronepronepositionspositions havehave uniqueunique applicationapplication wherewhere workwork isis spatiallyspatiallyrestricted,restricted, asas oftenoften thethe casecase withwith mechanics,mechanics, plumbers,plumbers, ororrepairmenrepairmen..

MaintainabilityMaintainability DesignDesign.. ImportantlyImportantly relatedrelated toto thethe overalloverallworkspaceworkspace layoutlayout problemproblem areare thethe designdesign andand arrangementarrangementofof componentscomponents foefoe easeease andand reliabilityreliability ofof maintenancemaintenance..

PoorPoor maintainabilitymaintainability designdesign cancan contributecontribute toto maintenancemaintenanceerror,error, inefficiency,inefficiency, andand accidentsaccidents.. ItIt isis desirabledesirable toto designdesignequipmentequipment soso thatthat thethe maintenancemaintenance doesdoes notnot interfereinterfere withwithororunnecessarilyunnecessarilydisruptdisrupt itsits operationoperation..


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AA briefbrief surveysurvey ofof majormajor designdesign principlesprinciples isis asas followsfollows::

1.1. LocateLocate parts,parts, assemblies,assemblies, andand fusesfuses soso thatthat theirtheir removalremoval

doesdoes notnot requirerequire removalremoval ofof otherother componentscomponents..2.2. ProvideProvide sufficientsufficient accessaccess forfor testtest probes,probes, soldering,soldering, irons,irons,

andand otherother toolstools..

3.3. PlugPlug--inin assembliesassemblies areare generallygenerally preferredpreferred toto soldersolderconnectionconnection..

4.4. UseUse aa minimumminimum ofof mountingmounting hardware,hardware, consistentconsistent withwithvibrationvibration andand stressstress..

5.5. ForFor frequentfrequent access,access, useuse hinges,hinges, andand pulloutspullouts withwith stops,stops,andand capitalizecapitalize onon accessaccess fromfrom bothboth sidessides..

6.6. UseUse handhand--operatedoperated fastenersfasteners or,or, alternatively,alternatively, slotted,slotted,hexhex--headhead screwsscrews thatthat permitpermit choicechoice ofof toolstools..

7.7. UU--lugslugs areare generallygenerally preferredpreferred toto OO--lugslugs forfor wirewireconnectionsconnections


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8.8. LabelLabel allall components,components, andand useuse colorcolor codescodes oror labelslabels totoidentifyidentify relationsrelations betweenbetween wireswires andand terminalsterminals andandbetweenbetween cablescables andand connectorsconnectors..

9.9. CablesCables shouldshould bebe routedrouted soso theythey areare notnot caughtcaught inin docrs,docrs,pinched,pinched, oror trippedtripped averaver operatorsoperators..

10.10. Aligning Aligning pinspins onon plugsplugs shouldshould havehave anan asymmetricalasymmetricalarrangementarrangement toto avoidavoid incorrectincorrect insertionsinsertions intointo

receptaclesreceptacles..

11.11. ProvideProvide sufficientsufficient accessaccess doorsdoors oror windowswindows ononcomponentscomponents thatthat requirerequire internalinternal adjustmentadjustment bybytechnicianstechnicians..

12.12. ConsiderConsider thethe anthropometricanthropometric characteristicscharacteristics ofoftechnicians,technicians, bothboth forfor easeease ofof accessaccess asas wellwell asas forfor useuse ofoftoolstools inin closeclose quartersquarters..


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BIOMECHANICAL, SAFETY, AND PRODUCT DESIGNBIOMECHANICAL, SAFETY, AND PRODUCT DESIGN

Biomechanics is concerned with the relation betweenBiomechanics is concerned with the relation between

physical force and the human body. Many people arephysical force and the human body. Many people areinjured or subjected to discomfort by equipment or productinjured or subjected to discomfort by equipment or productthat, forma biomechanics viewpoint are poorly designed.that, forma biomechanics viewpoint are poorly designed.Research in biomechanics. A field involving collaborationResearch in biomechanics. A field involving collaborationamong engineers and biomedical scientists, is focused onamong engineers and biomedical scientists, is focused on

the reduction of such trauma.the reduction of such trauma.

SystemsSystems SafetySafety EngineeringEngineering.. A A subspecialtysubspecialty thatthat givesgivesrecognitionrecognition toto thethe aboveabove viewview byby acknowledgeacknowledge thatthat maymay

accidentsaccidents areare inevitableinevitable .. SafetySafety andand efficiencyefficiency arearerecognizedrecognized toto bebe intrinsicallyintrinsically related,related, notnot separateseparate entriesentries..ItIt isis muchmuch concernedconcerned withwith thethe problemproblem ofof productproduct liabilityliability..


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ProductProduct LiabilityLiability.. TheThe operatoroperator broughtbrought suitsuit a gainstagainst thetheequipmentequipment manufacturer,manufacturer, claimingclaiming negligencenegligence inin designdesign;;

thethe injuryinjury foundfound thethe manufacturermanufacturer liableliable..

IndustrialIndustrialBiomechanicsBiomechanics..

human factors engineering ppp zhrp 1e

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