control engineering fundamentals, Lecture notes of Electronics

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MAGESH MANI LECTURER AERONAUTICAL DEPARTMENT Rajalakshmi Engineering College Thandalam 602 105

INTRODUCTION

System

 Collection of elements arranged in a particular sequence that act together and perform an objective in a coordinated manner  The system does not imply physical system alone. It includes abstract systems such as economics

What sorts of

Systems?

Many systems can be considered using control system techniques  (^) Vehicle Control and Design (land, sea, air, space) – understanding how the system responds to external disturbances  (^) Biomedical (cardiac system, dialysis machine) – design and control of the system with relation to human interaction  (^) Stock Market - understanding the relationship between interest rates and inflation where one drives the other  (^) Biological - determining the relationship between the outcome of a natural phenomenon when the system is disturbed

Representing a Control

System

 Block diagram shows relationship between components  Driver performs numerous functions including measurement, control and selecting destinations

Representing a Control

System

We can expand the driver block to show the various functions they perform

Automation

Room Temperature

Control

• (^) Rate of change of temperature α to temperature difference
• (^) Without feedback, system will reach different steady state depending on environment

Negative Feedback Control System  Two Types are Positive Feedback & Negative Feedback

• Positive Feedback never achieves automation Example: Oscillators, Inflation in Economy, Vicious Circle

* Negative Feedback only achieves automation Example:

All automation process, Virtuous Circle Automation means Negative Feedback

 Process or Plant System to be controlled including actuators and power amplifiers  Sensor Instrumentation that measures output and converts it to a signal  Compensator or controller System added to enhance performance of control loop

Mathematical

Modeling

• (^) To understand system performance, a

mathematical model of the plant is

required

• This will eventually allow us to design

control systems to achieve a particular

specification

Physical Systems



Hydraulic Systems



Thermal Systems



Pneumatic Systems



Mechanical Systems



Electrical Systems

Linear System

 What is Linear System? The system whose steady state output is always proportional to input is a Linear System. During transient state, this need not be maintained  A system whose transient output is proportional to input at the instant of the application of input is the zero order linear system  Zero order system is the simplest linear system to analyse, but most difficult to construct  Examples of Physical Systems