Laboratory in Automatic Control Lab1

8/2/2019 Laboratory in Automatic Control Lab1

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Laboratory in Automatic Control

Lab 1

MatLab Basics


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View or change current directory

Command Window

Current Directory

Command History

Status Bar


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Desktop | Desktop Layout | Default


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Editor M-file

File | New |Blank M-File


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Editor M-file

Command


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Debug | Save and Run F5


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Naming rules

The first letter of the filename must be English.

SPACE is not allowed to use.


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Matlab program

a=1 ;

b=2

c=3


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clc % clearing the Command Window


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clear all % clearing the Workspace


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Naming Variables

MATLAB variable names must begin with a letter, which may befollowed by any combination of letters, digits, and underscores.

MATLAB distinguishes between uppercase and lowercasecharacters, so A and a are not the same variable.

Avoid Using Function Names for Variables To test whether a proposed variable name is already used as a

function name, use

which -all variable_name


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Special Values

Function Return Value

ansMost recent answer (variable). If you do not assign an output variable to an expression,

MATLAB automatically stores the result in ans.

eps Floating-point relative accuracy. This is the tolerance MATLAB uses in itscalculations.

intmax Largest 8-, 16-, 32-, or 64-bit integer your computer can represent.

intmin Smallest 8-, 16-, 32-, or 64-bit integer your computer can represent.

realmax Largest floating-point number your computer can represent.

realmin Smallest positive floating-point number your computer can represent.

pi 3.1415926535897...

i, j Imaginary unit.

inf Infinity. Calculations like n/0, where n is any nonzero real value, result in inf.

NaNNot a Number, an invalid numeric value. Expressions like 0/0 and inf/inf result in a

NaN, as do arithmetic operations involving a NaN.

version MATLAB version string.

Several functions return important special values that you can

use in your M-files.


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How to use the HELP?


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Mathematical Operators

Mathematical Operators

+ Addition or unary plus.

- Subtraction or unary minus.

* Matrix multiplication.

.* Array multiplication.

/ Backslash or matrix left division.

./ Array left division.

^ Matrix power.

.^ Array power.

Matrix transpose.


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Example


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Subplot function

Syntax

Subplot(m,n,p)

Matlab code

x = -10:0.1:10;y = x.^2 ;

subplot(2,2,1),plot(x,sin(x))

subplot(2,2,2),plot(x,y,'--')

subplot(2,2,3),plot(-x)

subplot(2,2,4)

subplot(2,2,1),plot(x,sin(x)) subplot(2,2,2),plot(x,y,'--')

subplot(2,2,3),plot(-x) subplot(2,2,4)


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How to do exponential ?

Syntax

Y=exp(X)

Example

Matlab code

-0.2

When 5 10

and vector in increment of 0.2

Solve eX

X

X

Y

X = 5:0.2:10

Y = exp(-0.2*X)

Result


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Plot Function

Syntax

Plot(X, Y, 'PropertyName',PropertyValue,...)

Matlab code

Result

X = -pi:0.1:pi ;

Y = cos(X) ;Z = sin(X) ;

plot(X, Y, '-xr', X, Z, ':og') ;


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Matlab code

X = -pi:0.1:pi;Y = cos(X);

Z = sin(X);

plot(X, Y, '-xr', X, Z, ':og');

legend('cos_x','sin_x',0);

Xlabel('X');

Ylabel('Return Values');

title('Plot of function');

grid on;

Result

Legend

Ylabel

Xlabel

Title

Grid


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File | Save As

File Name


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2 '

-

1.

1 2 3 9 8 7

4 5 6 , 6 5 4

7 8 9 3 2 1

solve : ( ) , ( ) , ( ) , and ( )

2.

( ) plot: cos( )

(b) plot: sin( )

(c) plot: cos( ) and sin( )

(d) plot:note:

(1) subplot, (2) - ,0.1, (3)

x

A B

a A B b A B c A d B

a x

x

x x

e

x

title, (4) and ladel,

(5) grid, and (6) legend

x y

Lab1 Homework

Laboratory in Automatic Control Lab1

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