Download - Bag 1 Pengenalan Sistem Kontrol.ppt
Pengenalan Sistem Kontrol Topik Bahasan
Konsep Dasar Sistem KontrolJenis Sistem KontrolContoh-contohDesain Sistem Kontrol
Konsep Dasar Sistem Kontrol Sistem = Kombinasi komponen2 yang
bekerja bersama2 untuk mencapai tujuan tertentu (fisik atau abstrak,biologi,ekomoni)
Sistem Kontrol = sistem yang dapat di-identifikasi atau ditengarai terdiri dari minimal 2 (dua) bagian utama, yaitu:- Plant/proses, obyek yang dikendalikan- Kontroller/Pengendali, yang mengendalikan
Sistem Kontrol Loop Terbuka Sistem yang kelurannya tidak mempunyai
pengaruh terhadap aksi kendali Keluaran sistem tidak dapat digunakan
sebagai perbandingan umpan balik dengan masukan.
ProsesKontrollerMasukan 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 waktuContoh : - 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 tertutup
reference input signal,
comman
d
isyarat masukan
acuan, perintah, set-point
feedback signal
isyarat umpan-balik
output signal
luaran, isyarat luaran, hasil, produk
PROSES(PLANT)
control signal
isyarat kendali
PENGENDALI(CONTROLLE
R)
Contoh-Contoh Sistem Kontrol Sistem Kontrol Kecepatan – James Watt
Plant : engineControlled Variable : Engine speedControl Signal : jumlah Fuel
Contoh-Contoh Sistem Kontrol Radar 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 headingAutopilot hit demand rudder anglesteering
geerRudder menyebabkan hull(lambung kapal)
bergeser
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Road conditions
Speed
Steering
Noise
desired direction
actual direction
Response direction of travel
Time
Response speed
Time
Desired speed
Actual speed
Contoh-Contoh Sistem Kontrol Steering Automobile
Actual output
AutomobileSteering
mechanismDriver
Desired speed or direction
Process/
Plant
ActuatorController
Desired output
Actual output
Disturbance
Open-loop menggunakan actuating device untuk mengontrol process secara langsung tanpa feedback
Kerugian : sensitivity to disturbances and system’s inability to correct for these disturbances
Steering Automobile :Open loop
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Actual output
AutomobileSteering
mechanismDriver
Measurement
Comparison
Desired speed or direction
Process/
Plant
ActuatorController
Sensor
Desired output
Actual outputerror+
-
feedbackMeasurement output
Disturbance
SK Steering Automobile : Close loop
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feed-eye and resin bath
Filament winding process
Mandrel
Contoh 2: Komputer Kontrol untuk Mesin Tenun
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Master
Computer
Sub CPU
1
2
3
4
PWM 1
PWM 2
PWM 3
PWM 4
Motor 1
Motor 2
Motor 3
Motor 4
Motion 1
Motion 2
Motion 3
Motion 4
Contoh 2: Komputer Kontrol untuk Mesin Tenun
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2nd Motion control
DC/AC/stepping motor
PWM Unit
Optical
Encoder
Desired position of motion 2
Actual position
error+
-
Feedback: position signal
Speed feedback
Disturbance
Sub CPU #2
Tachogenerator
Contoh 2: Komputer Kontrol untuk Mesin Tenun
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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 response”
Steady state error
overshoot
Rise time
Time (s)
Out
put
Typical requirements:
• No overshoot• Zero steady state error• Rising time as small as possible
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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. Define the 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 simple mathematical 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 specifications
e.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 system components, 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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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 key parameters 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
T
IDP edtKeKeKV0
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Step 7: Analyze and simulate the controller, and select
key parameters to be adjusted
System characteristics to be analyzed include: transient response steady-state error stability sensitivity: system behavior changes with changes in component
values 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, KI
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Step 8: Test the controller on the real system.
Interference (Electromagnetic, noise, etc.)Hardware and softwareController parameters…...
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Step 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
Review: Steps of control system design
Step 7: Analyze and simulate the controller
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Specification: control goals, variables, etc.
Modeling and System Behavior
Controller design, PID; Root Locus analysis
Feedback systems
Time domain specifications & system stability
Frequency domain
Bode plot
Compensator design
Aspects of industrial PID State variable
Autotuning rules of PID Analysis & design
Materi Sistem Kontrol Dasar
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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)steady-
state 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.