Simulink Presentation

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SIMULINK INTRODUCTION

Sadaf Anjum

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Lecture Overview

What is Simulink? How to use Simulink

Getting Start with Simulink Building a model

Example 1 (Differential Equations ) Example 2 (Transfer Function) Creating Subsystems System modeling example System Identification

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Example 1 (Differential Equations ) Example 2 (Transfer Function) Creating Subsystems Useful Information System Identification

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Simulink

Is a software package for modeling, simulating, and analyzing dynamic systems.

Supports linear and nonlinear systems, modeled in continuous time, sample time, or a hybrid of the two.

For modeling, it provides a graphical user interface (GUI) for building models as block diagrams (using click-and-drag mouse operations)

You can simulate, analyze the output results, explore, revise your models.

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Start a Simulink Session

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Start a Simulink Session

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Simulink Library Browser

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Create a New Model

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Building a Model

Simulink Block Diagram – clear model of a dynamic system

Each block represents an elementary dynamic system that produces an output (either continuous or discrete output)

Lines represent connections of block inputs to block outputs

u(Input)

x(states)

y(Output)

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The following steps will guide you to construct a system/model:

STEP 1: Creating Blocks

STEP 2: Making connections

STEP 3: Set Parameters

STEP 4: Running Simulation

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Step 1: Creating Blocks

Click-Drag-Drop the Sine Wave block to Workspace Window

This is the Sine Wave block is

from the Sources library

Sources library

Save this model

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Step 1: Creating Blocks

These arefrom the Sinks

library

The Gain block isfrom the

Math library

The Mux block is from the Signals &Systems library

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Step 2: Making connectionsTo make connection: left-click while holding down control key (on keyboard) and drag from source port to a destination port

A connected Model

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Gain value = 5

Name the output parameter as “out1”

Double click the Gain block to set the parameter for the Gain block

Step 3: Set Parameters

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View output via Scope block

Double click on Scope block to display output of the scopeNote: Scope block is similar to oscilloscope!

Output of the scope

Yellow: Input sine wavePurple: Output (sine wave with gain of 5

To fit graph to frame

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Three outputs show here

View output (workspace)

You can plot the output using the plot function

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Example 1:Differential Equations Example of a dynamic system:

1x Bx Kx f t

M

The Mathematical model of the system is describe by:

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2x x x f t

Lets M=2kg; B = 2 Ns/m; K=2 N/m

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Unit Step Input

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Use Simulink to simulate the step response of the system, i.e.


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2x x x f t

f(t), N

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0 Time, s

Select BLOCK set Location in Simulink Library

Step Sources

Sum Math Operation

Gain Math Operation

Integrator Continuous

Scope & To Workspace Sinks

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2x x x f t

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2x x x f t

STEP 2: Making connections

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Continue…Step 4 Run SimulationStep Response for system example

Output from Scope block Plot system response

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Example 2: Transfer Function Use the system example and simulate the

response using transfer function approach

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2x x x f t

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( ) 1

( ) 2 2 2

X s

F s s s

The transfer function of the equation (assume all initial conditions =0)

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Select BLOCK set Location in Simulink Library

Step Sources

Transfer Function Continuous

Scope & To Workspace Sinks

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Continue… STEP 2: Making

connections

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( ) 1

( ) 2 2 2

X s

F s s s

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Step 3 set parameters

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Step 4 Run Simulation

Output from Scope blockPlot system response

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Creating Subsystems

Subsystem – similar to “Subroutine” Advantage of Subsystems:

Reduce the number of blocks display on the main window (i.e. simplify the model)

Group related blocks together (i.e. More organized)

Can create a hierarchical block diagram (i.e. you can create subsystems within a subsystem )

Easy to check for mistakes and to explore different parameters

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Create Subsystem using model in Example 1STEP 1: Creating Blocks (Main window)

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STEP 2: Double click Subsystem block and create a model in the Subsystem block

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STEP 3: Making connections (Main window)

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STEP 4: Set Parameter (Main window)STEP 5: Running SimulationThen view output response

Output from Scope block

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Example 1 (Differential Equations ) Example 2 (Transfer Function) Creating Subsystems System Modeling example System Identification

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System modeling Example.

Moment of inertia of the rotor (J) = 3.2284E-6 kg.m^2/s^2

Damping ratio of the mechanical system (b) = 3.5077E-6 Nms

Electromotive force constant (K=Ke=Kt) = 0.0274 Nm/Amp

Electric resistance (R) = 4 ohm Electric inductance (L) =

2.75E-6 H Input (V): Source Voltage

Output (theta): position of shaft

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System Identification

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Coninue…

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This is the identified model of the unknown system.

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THANK YOU…

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Simulink Presentation