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Dede Iskandar, ST

pengenalan sistem kontrol

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sistem kontrol

Text of pengenalan sistem kontrol

Dede Iskandar, ST

Pengenalan Sistem Kontrol

Topik Bahasan Konsep Dasar Sistem Kontrol Jenis Sistem Kontrol Contoh-contoh

Desain Sistem Kontrol

Konsep Dasar Sistem KontrolSistem = Kombinasi komponen2 yang bekerja bersama2 untuk mencapai tujuan tertentu (fisik atau abstrak,biologi,ekomoni) Sistem Kontrol = sistem yang dapat diidentifikasi atau ditengarai terdiri dari minimal 2 (dua) bagian utama, yaitu:- Plant/proses, obyek yang dikendalikan- Kontroller/Pengendali, yang mengendalikan

Jenis Sistem Kontrol

Secara garis besarSistem Kontrol Loop terbuka Sistem Kontrol Loop tertutup

Sistem Kontrol Loop TerbukaSistem yang kelurannya tidak mempunyai pengaruh terhadap aksi kendali Keluaran sistem tidak dapat digunakan sebagai perbandingan umpan balik dengan masukan.Masukan

Kontroller

Proses

Keluaran

Sistem Kontrol Loop TerbukaKarakteristik Sistem kendali lup terbuka : output tidak diukur maupun di umpanbalikkan bergantung pada kalibrasi hubungan antara output dan input diketahui tidak ada internal disturbance maupun eksternal disturbance terkait dengan waktu

Sistem Kontrol Loop TerbukaKelebihan: konstruksinya sederhana dan perawatannya mudah lebih murah tidak ada persoalan kestabilan cocok untuk keluaran yang sukar diukur /tidak ekonomis (contoh: untuk mengukur kualitas keluaran pemanggang roti)

Sistem Kontrol Loop TerbukaKelemahan: gangguan dan perubahan kalibrasi untuk menjaga kualitas yang diinginkan perlu kalibrasi ulang dari waktu ke waktu Contoh : - kendali traffic (lalu lintas) - mesin cuci

Sistem Kontrol Loop tertutup- Sistem yang memiliki umpan balik untuk mengurangi kesalahan atau beda antara masukan acuan dengan keluaran

Sistem Kontrol Loop tertutupreference input signal, commandisyarat masukan acuan, perintah,

control signal

(CONTROLLER)

PENGENDALI

isyarat kendali

feedback signalisyarat umpan-balik

PROSES (PLANT)

output signalluaran, isyarat luaran, hasil, produk

set-point

Contoh-Contoh Sistek Kontrol

Open Loop

Pemanggang Roti

Motor DC

Contoh-Contoh Sistem Kontrol

Sistem Kontrol Kecepatan James WattPlant : engine Controlled Variable : Engine speed Control Signal : jumlah Fuel

Contoh-Contoh Sistem Kontrol

Kontrol Manipulator Robot

Contoh-Contoh Sistem Kontrol

Sistem Kontrol Temperatur

Contoh-Contoh Sistem Kontrol

Kontrol Elevator Pesawat

Contoh-Contoh Sistem Kontrol

Sistem Kontrol Level

Contoh-Contoh Sistem Kontrol

SK Radar Tracking Pesawat

Radar mendeteksi posisi & kec pesawat

Contoh-Contoh Sistem KontrolRadar mendeteksi posisi & kec pesawat Dipakai komp u menentukan lead & firing angle penembak Sudut2 ini diumpankan ke power amp sebagai driver motor Feedback signal menjamin alignment penembak sesuai yang diset komputer

Contoh-Contoh Sistem Kontrol

SK Autopilot Kapal Laut

Gyro-Compas u ngitung actual heading Autopilot hit demand rudder anglesteering

geer Rudder menyebabkan hull(lambung kapal) bergeser

Contoh-Contoh Sistem Kontrol

SK Autopilot Kapal Laut

Contoh-Contoh Sistem Kontrol

Steering AutomobileSpeed actual direction desired direction

Noise

Response direction of travelRoad conditions Steering

Time Desired speed Actual speed21

Response speed

Time

Steering Automobile : Open loopDesired speed or direction Steering Driver mechanism Automobile Actual output

Desired output

Disturbance Controller Actuator Process/ Plant

Actual output

Open-loop menggunakan actuating device untuk mengontrol process secara langsung tanpa feedback Kerugian : sensitivity to disturbances and systems inability to correct for these disturbances

SK Steering Automobile : Close loopDesired speed or direction Steering Actual output Automobile

Comparison

Driver

mechanism

Measurement

Desired output +-

Disturbance error Controller Actuator Process/ Plant feedback

Actual output

Measurement output Sensor

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Contoh-Contoh Sistem Kontrol

Mesin Tenun

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Contoh 2: Komputer Kontrol untuk Mesin TenunMandrel

feed-eye and resin bath

Filament winding process25

Contoh 2: Komputer Kontrol untuk Mesin TenunSub CPU

Motion 11Master Computer 2 PWM 2 PWM 3 PWM 4 Motor 2 PWM 1 Motor 1

Motion 4 Motion 23 4 Motor 3 Motor 4

Motion 3

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Contoh 2: Komputer Kontrol untuk Mesin TenunDesired position of + motion 2 Disturbance error Sub CPU #2 PWM Unit DC/AC/step ping motor Actual position 2nd Motion control

Tachogenerator Speed feedback Feedback: position signal

OpticalEncoder

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Desain Sistem Kontrol

Performance specifications:

It is very important to define, in numerical terms, what is the expected performance of the control system One possibility is to examine the behavior of the output in response to a sudden change in input: known as the step responseovershoot

Typical requirements:

No overshoot Zero steady state error Rising time as small as possible

Steady state error

Rise time Time (s)29

Control System Design(1) Understand the system to be controlled. Define the objectives of the controller (establish control goals) (2) Identify the variables to control, build a simple mathematical model of the system and examine the system behavior. Does the model captures essential features of the system? If not revise the model. (3) Write the specifications for the variables (4) System configuration: sensor, controller, actuator, etc. (5) Developing a model of the process, the actuator, and the sensor (6) Describe a controller, select key parameters to be adjusted. (7) Analyze and simulate the controller. Are objectives achieved? If not, change the control strategy and redesign (8) Test the controller on the real system. Can the control law be fine tuned to achieve desired behavior? If not iterate until a satisfactory solution is obtained

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Step 1: Understand the system to be controlled. Definethe objectives of the controller (establish control goals) For example : control goal: to control the velocity of motor accurately or to control the direction of the motor

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Step 2: Identify the variables to control, build a simplemathematical model of the system and examine the system behavior.

control variable: angular of steering wheel mathematical model: f(v, t, P) control variable: position of each motion mathematical model: f(x, y, z, , v, t)

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Step 3: Write the specificationse.g. range of control variable values accuracy of control rise time of system response percent overshoot the response settling time peak time ...

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Step 4: System configuration: choosing control systemcomponents, which are assembled into a viable system, based upon requirements.

Sensor: tachogenerator, optical encoder, etc. Actuator: AC/DC servo motor with reduction gear boxes Controller: PWM unit; microcomputer for position control of each motion; PC used as master computer, to control the coupling movement of several motions Control algorithm: PID controller Computer programming language: C++ and Assembler

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DC motor

Optical encoder

tachometerhttp://www.micromo.com/35

Step 5: Developing a model of the process,the actuator and the sensor. model of the winding process AC/DC servo motor model Encoder and other sensor models

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Step 6: Decide on a control strategy, select keyparameters to be adjusted. In example 1: possible control law: P controller Throttle=K*(desired speed - actual speed)

In example 2: possible control law: PID controller

V K P e K D e K I edt037

T

Step 7: Analyze and simulate the controller, and selectkey parameters to be adjusted System characteristics to be analyzed include: transient response steady-state error stability sensitivity: system behavior changes with changes in componentvalues or system parameters, e.g. temperature, pressure, etc. (systems must be built so that expected changes do not degrade performance beyond specified bounds)

evaluation of time response of the system for a given input Parameters to be adjusted: KP, KD, KI38

Step 8: Test the controller on the real system.

Interference (Electromagnetic, noise, etc.) Hardware and software Controller parameters

...

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Review: Steps of control system designStep 1: Establish control goals

Step 2: Identify the variables to control

Step 3: Write the specifications for the variables

Step 4: System configuration: sensor, controller, actuator, etc.

Step 5: developing models for process, actuator, sensors

Step 6: Describe a controller, select key parameters Step 7: Analyze and simulate the controller40

Materi Sistem Kontrol DasarSpecification: control goals, variables, etc. Modeling and System Behavior

Feedback systemsTime domain specifications & system stability Controller design, PID; Root Locus analysis

Frequency domainBode plot Compensator design

Aspects of industrial PID Autotuning rules of PID

State variable Analysis & design41

Review questions:(1) Give examples of open-loop systems (2) Name several applications for feedback control system (3) Name reasons for using feedback control systems and reasons for not using them (4) Functionally, how do closed-loop systems differ from open-loop systems? (5) Name two possible control law for motion controls (6) Name advantages of having a computer in the control loop (7) Three major design criteria. (1) transient response, (2)steadystate error and (3) stability. Briefly describe the criteria. (8) Name components in a control system (9) Briefly describe performance specifications of control systems (10) Describe steps of a control system design.

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ReferensiSistem Kontrol Otomasti, K Ogata Automatic Control System, Benjamin C Kuo Advance Control Engineering, Ronald SB Internet dll