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CONTROL ENGINEERING

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Introduction

Technology development in 20th century have madepossible

High speed bullet trains

Exotic vehicles

Safe, comfortable and efficient automobiles

Military aircraft

Huge transport and luxury ships

Efficient robotic assembly lines etc..

The successful operation of all these systems depends onthe proper functioning of the large number of controlsystems used in such ventures.

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Introduction to Control Systems

Example 1

The setting of the darkness knob ortimer, represents the input quantity andthe degree of darkness and crispness ofthe toast produces is output quantity.

If the degree of darkness is notsatisfactory, this condition can in no wayautomatically alter the length of timer thatheat is applied.

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Introduction to Control Systems

Example 2

The dc shunt motor in figure is anotherexample .

For a given value of field current a required

value of voltage is applied to the armature toproduce the desired value of motor speed.

A variation of the speed from the desiredvalue, due to a change of mechanical load

on the shaft, can in no way cause a changein the value of the applied armature voltageto maintain the desired speed.

Therefore, the output quantity has noinfluence on the input quantity.

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Open Loop Control Systems

System in which the output quantity has no effect uponthe input quantity are called open loop control systems.

The examples just cited are represented symbolically by afunctional block diagram, as shown in figure below

Heating Example

Motor Example

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Close Loop Control System

Systems in which the output has a direct effect upon theinput quantity are called close loop control system

Comparison element

Control unit

Correction unit

Process plant

Measuring deviceReference input

Controlled variable

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Close Loop Control System

Example of person with thermometer

Speed control of motor

Block diagram

Rules

Modeling

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System

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Translational Mechanical System