Examples
EXAMPLE
1  Modeling
an Equation
This example demonstrates how an equation can be modeled using
Simulink. Let's consider the temperature conversion equation:
In your model
window, create (drag from libraries) the following blocks:
 Ramp block
from Sources library
 Constant block
from Sources library
 Gain block
from Math library
 Sum block
from Math library
 Scope block
from Sinks library
then make a connection
as shown in the figure below
and the display
of the scope would look like this:
For an exercise,
create a Simulink model to convert Fahrenheit to Celsius degree,
or
EXAMPLE 2  Modeling
a Continuous System
In this example, the dynamics of a physical system is represented
by
where x and u
are functions of time t. Input u(t) is a square wave with
amplitude = 1; frequency = 1 radian/sec. In the time domain,
Simulink represents the system as
and the scope
display should look like this:
You may also consider
the system in the frequency domain by taking Laplace transform
of the firstorder linear differential equation above.
From the Laplace transform, we have
This is the transfer
function of the system. In Simulink you can use Transfer Fn
block to represent the above relation. The model may
look like this:
which is considerably
simpler than the previous model and provides the exact same
result.
NOTE: You must
change the paramters in the blocks such as in the case for
the Transfer Fcn block to change from the default values to
your model specifics. To change the parameters, double click
on the block and a new window will pop up to prompt you for
inputs/changes.
