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Page 1: Week14 Controls

KU1101 Pengantar Rekayasa dan Desain I

Control

Luaran pertemuan pekan keempatbelasMahasiswa memahami prinsip pengendalian sistem

Mahasiswa dapat mengenali elemen-elemen dari sebuah sistem denganpengendalian

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uncontrolled

controlled

What is Control ?Microsoft® Encarta® Reference Library 2003

operate, work, run, use, utilize, manipulate, maneuverrestrain, limit, restrict, hold back, rein in, containmanage, command, supervise, organize, run, directrule, manipulate, influence, dominate, oppress, have a hold over, hold sway over, dictateoversee, monitor, regulate, inspect, limit, restrict

Merriam-Webster :to direct the actions or function of (something) : to cause (something) to act or function in a certain way

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Open loop vs Closed loopOpen loop

No feedback

INPUTTap handle

OUTPUTWater flowSYSTEM

Open loop vs Closed loopClosed loop

Feed backsensor

INPUTDesired water level

OUTPUTWater level

SYSTEM

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Open or closed loop ?

Mesin pengering gabah

Open or closed loop ?

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Governor -> control steam engine pressure

Boulton-Watt steam engine

Balls fly out as speed

increases,

Valve closes,slowing engine

Flyballgovernor

Steamengine

Human body

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Control System Element

Control Unit strategyOn-offProportionalOthers : PID (proportional-integral-dirivative), model based, etc

Air Conditioning

Elements:Controlled variable : ambient temperatureReferences value : temperature settingComparison Element : thermostat (RTD)Error Signal : temperature differenceControl Unit : thermostat (on-off)Correction Unit : air conditioning unitProcess : room temperatureMeasuring device : thermostat

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Toilet water tank

Elements :Controlled variable: water levelReference value: initial setting of float & leverComparison element: leverError signal: difference setting vs lever positionControl unit: pivoted lever (proportional)Correction unit: valveProcess: water level in tankMeasuring device: floating ball & lever

Iron

Elements:Controlled variable : plate temperatureReferences value : temperature settingComparison Element : thermostat (RTD)Error Signal : temperature differenceControl Unit : thermostat (on-off)Correction Unit : electric plate heaterProcess : plate temperatureMeasuring device : thermostat

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ExerciseMicrowave ovenWater pumpSegway

Elements:Controlled variable :References value :Comparison Element :Error Signal :Control Unit :Correction Unit :Process :Measuring device :

Purpose of controlTo regulate : maintain certain steady state condition with respect to disturbanceTo manipulate (tracking) :perform a specific predefined task

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Copy-milling machine

Elements:Controlled variable :References value :Comparison Element :Error Signal :Control Unit :Correction Unit :Process :Measuring device :

System QualitiesStability

the quality or state of something that is not easily changed or likely to change (Merriam-Webster)The ability of a system to return to its initial/new steady state condition in respond to a disturbance after a certain time

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PerformanceHow fast a system response to a disturbance/voluntary change

Robustness How big disturbance can be manage by the system

Challenge in controller development to determine a proper corrective action from the controller that result in system stabilityto determine a proper action from the controller that result in a new desired condition