pengenalan sistem kontrol

2. Pengenalan Sistem Kontrol
 Topik Bahasan
Konsep Dasar Sistem Kontrol
Jenis Sistem Kontrol
Contoh-contoh
Desain Sistem Kontrol

3. 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

4. Jenis Sistem Kontrol
 Secara garis besar
 Sistem Kontrol Loop terbuka
 Sistem Kontrol Loop tertutup

5. 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

6. Sistem Kontrol Loop Terbuka
Karakteristik 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

7. Sistem Kontrol Loop Terbuka
Kelebihan:
 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)

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

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

10. Sistem Kontrol Loop tertutup
reference
input
signal,
command
isyarat
masukan
acuan,
perintah,
set-point
feedback signal
isyarat umpan-balik
output signal
luaran, isyarat
luaran, hasil,
produk
PROSES
(PLANT)
control signal
isyarat kendaliPENGENDALI
(CONTROLLE
R)

11. Contoh-Contoh Sistek Kontrol
 Open Loop
Pemanggang Roti Motor DC

12. Contoh-Contoh Sistem Kontrol
 Sistem Kontrol Kecepatan – James Watt
Plant : engine
Controlled Variable : Engine speed
Control Signal : jumlah Fuel

13. Contoh-Contoh Sistem Kontrol
 Kontrol Manipulator Robot

14. Contoh-Contoh Sistem Kontrol
 Sistem Kontrol Temperatur

15. Contoh-Contoh Sistem Kontrol
 Kontrol Elevator Pesawat

16. Contoh-Contoh Sistem Kontrol
 Sistem Kontrol Level

17. Contoh-Contoh Sistem Kontrol
 SK Radar Tracking Pesawat
Radar mendeteksi posisi & kec pesawat

18. 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

19. Contoh-Contoh Sistem Kontrol
 SK Autopilot Kapal Laut
Gyro-Compas u ngitung actual heading
Autopilot hit demand rudder anglesteering
geer
Rudder menyebabkan hull(lambung kapal)
bergeser

20. Contoh-Contoh Sistem Kontrol
 SK Autopilot Kapal Laut

21. 21
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

22. Actual
output
Automobile
Steering
mechanism
Driver
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

23. 23
Actual
output
Automobile
Steering
mechanism
Driver
Measurement
Comparison
Desired
speed or
direction
Process/
Plant
ActuatorController
Sensor
Desired
output
Actual
outputerror+
-
feedbackMeasurement output
Disturbance
SK Steering Automobile :
Close loop

24. 24
Contoh-Contoh Sistem Kontrol
 Mesin Tenun

25. 25
feed-eye and resin bath
Filament winding process
Mandrel
Contoh 2: Komputer Kontrol
untuk Mesin Tenun

26. 26
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

27. 27
2nd Motion
control
DC/AC/step
ping 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

28. Desain Sistem Kontrol

29. 29
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)
Output
Typical requirements:
• No overshoot
• Zero steady state error
• Rising time as small as
possible

30. 30
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

31. 31
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

32. 32
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, ϕ, v, t)

33. 33
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
 …...

34. 34
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

35. 35
DC motor
tachometer
Optical encoder
http://www.micromo.com/

36. 36
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

37. 37
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 edtKeKeKV
0


38. 38
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

39. 39
Step 8: Test the controller on the real system.
Interference (Electromagnetic, noise, etc.)
Hardware and software
Controller parameters
…...

40. 40
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

41. 41
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

42. 42
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.

43. Referensi
 Sistem Kontrol Otomasti, K Ogata
 Automatic Control System, Benjamin C
Kuo
 Advance Control Engineering, Ronald
SB
 Internet
 dll