1. Pengantar Sistem Pengendalian

1Introduction to Automatic

Control System

Faridah, ST. MSc

Manual (human) level control system

2Automatic level control system

Controller

Sensor

Valve/actuator

Control Systems

A control system is an interconnection of components forming a system configuration that will provide a desired system response.

The process is the component (or group of components) to be controlled.

The controller is the component (or group of component) that controls the process.

Control is automatic if it is accomplished without manual (human) intervention.

3Process

The process outputs are the variables to be controlled.

The process inputs are the variables that are manipulated by the controller.

Controller

The controller outputs are the variables that manipulate the process.

The controller inputs include the desired values of the process output variables, and may also include the actual of values of the process variables ( the process variables).

The objective of the controller is to make the actual values of the process output variables equal to the desired values.

4Single - Input, Single -Output Process

Open-Loop Control

Desired speed set in terms of amplifier input voltage. (An accurate motor - amplifier model is required!)

Speed errors are Speed errors are not corrected.

5Closed-Loop Control

Desired speed set in terms of tachometer voltage. (An accurate motor-amplifier is model is

not required). Speed errors are corrected.

Why study automatic control system?

We build control systems for four primary reasons: Power amplification Remote control Convenience of input form Compensation for disturbances

Automatic control of industrial processes (chemical, paper, automotive, etc.) is called automation. Automation enables: less expensive products, more reliable and higher quality products, quick adaptation to changes in markets.

Automatic control is crucial to: appliances and communication systems, military and aviation systems, computer disk drives and printers, etc.

6a. Early elevators were controlled by hand ropes or an elevator operator. Here, a rope is cut to demonstrate the safety brake, an innovation in earlyelevators;b. Modern Duo-lift elevators make their way up the Grande Arche in Paris, driven by one motor, with each car counterbalancing the other. Today, elevators are fully automatic, using control systems to regulate position and velocity.

Elevators Photos courtesy of United Technologies Otis Elevator.

Rover was built towork in contaminatedareas at Three MileIsland in Middleton,PA, where a nuclearaccident occurred in1979. The remotecontrolled robots long arm can be seen at the front of the vehicle.

Photo Hank Morgan/Rainbow/PNI.

Robot

7Video Laser Disc

What is important in a control system?

Response speed Accuracy

dynamic overshoot steady-state error

Stability Robustness

errors in models non-linear and variable process dynamics effects of disturbances

Elevator input and output

8Case Study 1

Fluid Level Regulator

Case Study 1

Fluid Level Regulator

9Case Study 2:Antenna Azimuth (Position Control System)

System concept

Case Study 2:Antenna Azimuth (Position Control System)

Detailed layout

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Case Study 2:Antenna Azimuth (Position Control System)

Schematic

Case Study 2:Antenna Azimuth (Position Control System)

functional block diagram

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Case Study 2:Antenna Azimuth (Position Control System)

Response of a position control system showing effect of high and low controller gain on the output response

Control Engineering

Control engineering is concerned with the the analysis, design, and implementation of goal-oriented systems.

Goal-oriented systems attempt to either : Regulate to maintain systems variables at

constant desired values (automobile, cruise control, room temperature, etc.)

Servo to make system variables follow continually changing desired values (robot motion, missile guidance, etc.)

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The control system design process

Test waveforms used in control systems

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Course Objective

Introduction to Automatic Control System Mathematical model of system (Modeling in

frequency domain) Time Response Transfer function and Block Diagram System Response Steady state error Stability Root Locus technique and design via root locus

Referensi

Nise, N.S., 2000, Control Systems Engineering, ed. 3, John Wiley & Sons, Inc.

Ogata, K., 1997, Modern Control Engineering, ed. 3, Prentice Hall.