Mechanics

Oct 31, 2013 (5 years and 2 months ago)

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LOGIKA & PEMROGRAMAN
KOMPUTER

MATLAB

PEMBENTUKAN SISTEM KONTROL

TEKNIK MESIN

FAKULTAS TEKNIK UNUD

2009

Creating hierarchical models using subsystems.

Writing S
-
functions for Customization & Creating
new blocks.

Implementation of Conditions & Logics.

Creating Virtual Worlds & Animations.

Soft Computing in Control.

Real
-
Time Technology & Hardware in the Loop
Simulations.

Example: A Control System

This example illustrates the modeling of a more complex
system, which is the thermodynamics of a house and its
temperature control system. This demo also illustrate the
usage of
subsystems

to create
hierarchical models
.

S
-
Functions

You can use
S
-
Functions

to
customize

and
create

blocks.

An interesting example is providing
custom animations

for
-
diagram models.

A simple example of a
mass
-
spring sys with an
animation S
-
Function

is provided
as a demo named
dblcart1
in the software documentation.

A general M
-
file S
-
function template
is also provided in:
C:
\
MATLAB
\
toolbox
\
\
blocks
\
sfuntmpl.m

which can be used as a guide to write M
-
file S
-
functions.
Writing S
-
Functions

PDF guide.

Implementation of

Conditions &Logics

Conditionally Executed Subsystems:

enabled/triggered/triggered
-
enabled subsystems

Control Flow Statements & Blocks

StateFlow:

For implementation of more complex Flow Control
Logics (Event
-
controlled models)

Virtual Reality Toolbox

SimMechanics

What Is SimMechanics?

SimMechanics is a block diagram modeling
environment for the engineering design and
simulation of rigid body machines and their
motions, using the standard Newtonian
dynamics of forces and torques.

Physical vs. Mathematical
Modeling

represent
mathematical operations or operate on signals,

Physical Modeling blocks:

represent
physical components or relationships directly,

Note:

Sensors & Actuators

are used to connect
these two kinds of blocks.

SimMechanics Analysis Modes:

Forward Dynamics analysis:

integrates applied
forces/torques, maintaining imposed constraints, and
obtains resulting motions.

Inverse Dynamics analysis:

finds the
forces/torques necessary to produce user
-
specified
motions in topologically open systems.

Kinematics analysis:

finds the forces/torques
necessary to produce user
-
specified motions in
topologically closed (loop) systems.

Trimming analysis:

equilibrium states of a system.

SimMechanics Block Libraries

Bodies Library

Joints Library

Constraints & Drivers
Library

Sensors & Actuators
Library

Force Elements
Library

Utilities Library

Essential Steps to Build a Model

1.
Select Ground, Body, and Joint blocks.

2.
Position and connect blocks.

3.
Configure Body blocks.

4.
Configure Joint blocks.

5.
Select, connect, and configure Constraint and
Driver blocks.

6.
Select, connect, and configure Actuator and
Sensor blocks.

7.
Encapsulate subsystems.

Example#1

Modeling a Double Pendulum

Example#2

One Degree of Freedom Mass
-
Spring
-
Damper System

Solution Methods:

MATLAB:

Solving the DE with an IVP/ODE solver

Control Toolbox:

Transfer Fcn, State Space Modeling

DE
-
solving, Transfer Fcn, State Space

SimMechanics:

Physical Modeling

Using Body Spring & Damper

Using Joint Spring & Damper

Using Sensor
-
Actuator Feedback

Assignment

2
-
D Bounce & Pitch Vehicle Model

Model the suspension system physically using
SimMechanics.

Compare the modeling approach with the
mathematical one, done previously using Simulink.