Matlab Tutorial For Eece 360

EECE 360

Matlab Tutorial Jan 29 2008

Outline  What

is Matlab?  Matlab Interface  Basic Syntax  Plotting Graphs  Control System Toolbox  Examples  Useful Resources

Overview of Matlab

What is Matlab?  Language

for technical computing  Supports mathematical computation, visualization, and programming  Composed using high-level programming language  similar

 For

to syntax of C

EECE 360

 Use

Matlab in the assignments

Matlab Interface

Workspace

Command History

Change the current directory to the location of your Matlab file at startup

Command Window

Matlab Programming  Two

Approaches

 Coding

in Command Window

Good

for short programs Commands must be re-entered each time you run a simulation  Coding Good

with .m-files

for long programs Allows users to save all the commands written in the .m-files

Command Window Interface

Write your commands here

(1) Creating .m-files File  New  MFile (2) Opening .m-files File  Open  select the .m-file

.m-file Interface

Write your commands here

To run the program, press F5

Workspace Interface  The

workspace provides a summary of the variables

Command History Interface  The

Command History stores all the commands entered in the Command Window previously  No

history of .m-files is shown here

Syntax Errors  All

errors are given in the Command Window in red  Nature

of error is explained

Examples on Matlab Interface

Basic Syntax

Basic Syntax  Assignment

of Variables

 Syntax:

Variable = Expression  Example: A = 1;  Use

of semi-colons

 With

semi-colon – suppress output  Without semi-colon – displays output in command window  Adding  Add

comments

% before command line

Example:

% This is a demo

Basic Syntax (cont’d)  Step

increment

 Example:

k = 1:0.1:10  k is a row-matrix from 1 to 10 with step size = 0.1  Matrix

Expression Row-matrix

 Hence, A

Column-matrix

for a 2x2 matrix, the syntax is

= [1 2; 3 4]

Basic Syntax (cont’d)  Mathematical

(Array) Operators

Mathematical

Mathematical Array

+

Addition

+ Addition

-

Subtraction

-

* /

Multiplicatio n Division

.* Multiplicatio n ./ Division

^

Power

.^ Power

 Note

Subtraction

the dimension of matrix in matrix computation

 Example:

A: 2x1 matrix, B: 2x2 matrix A*B  invalid operation B*A  valid operation

Basic Syntax (cont’d)  Common

Built-in Math Functions

 sin(x)

- sine  cos(x) - cosine  tan(x) - tangent  exp(x) - exponential  log10(x) – base10 logarithm  sqrt(x) – square root  abs(x) – absolute value  The

complete list can be found on pp. 833 of text

Examples on Basic Syntax

Plotting Graphs

Plotting Graphs  Matlab

allows graphical displays

 By

using the command plot  Syntax: plot(x)  Types

of plots -

Solid line

-- Dashed line

 Syntax:

:

Dotted line

-.

Dashdot line

plot(x,’-’)

Plotting Graphs (cont’d)  Labeling

Graphs

 Commonly

used Syntax:

ylabel(‘text’)

– label y-axis xlabel(‘text’) – label x-axis title(‘text’) – label title legend(‘legend1’, ‘length2’,…) – puts legend on current plot grid on (grid off) – add (remove) grid lines to figure subplot – subdivides graphic window hold on – hold the previous plot on the graphic window

Example (1)

Example (2) subplot(2,2,1) plot(x,’r’),hold on plot(y,’--’)

subplot(2,2,2) plot(x,’r’),hold on plot(y,’--’)

subplot(2,2,3) plot(x,’r’),hold on plot(y,’--’)

subplot(2,2,4) plot(x,’r’),hold on plot(y,’--’)

Examples on Plotting Graphs

Control System Toolbox

Overview to the Toolbox  Modeled

control systems as (1) transfer functions (2) zero-pole-gain (3) state-space form  Can manipulate both (1) continuous-time system (2) discrete-time system  Can compute and graph (1) time response (2) frequency response

Demo (1)  Transfer  Syntax:

Function tf(numerator, denomintor)

Demo (2)

 State-space  Syntax:

Representation

sys_ss = ss(sys)

Demo (3)  Finding

Poles and Zeros

 Syntax:

z = zero(sys) p = pole(sys)

 Pole-Zero  Syntax:

Diagram

zplane(z,p)

Demo (4)  Closed-Loop  Syntax:

+

System

CLsys = feedback(sys1,sys2)

System 1 -

System 2

Demo (5)  Step

Response

 Syntax:

step(sys)

Demo (6)  Pole-zero  Syntax:

 Impulse

cancellation

sysr = minreal(sys);

Response

 Syntax:

impulse(sys)

Examples on Control System Toolbox

Useful Resources  Appendix  End

A of Textbook

of Chapter – Matlab Demo

 http://www.mathworks.com