Multiplication Of Control System Polynomes In MatLab®

The reduction of sets of polynomials into one transfer function of a system is a very important work in control systems engineering. Matlab® provides various kinds of commands for this. One of these commands is the ‘conv()’ command.

Here we show you how to use the ‘conv()’ command to multiplicate the polynomials in Matlab®. 

Use Of The ‘conv()’ Command In MatLab® For Transfer Functions

There can be different polynomials in closed-loop or open-loop control systems to be multiplicated. Consider a situation that we have two polynomials in s-domain like them; 

x = 3s^2+5s-3;

y = 2s^3+2s+1;

Take a look at the very basic code below; 

>> x = [0 3 5 -3];
y = [2 0 2 1];
z = conv(x,y)

z =

     0     6    10     0    13    -1    -3


In this example, we defined two variables ‘x’ and ‘y’ which include the coefficients of the polynomials in the s-domain. And we typed these variables inside the ‘conv()’ command to get the result. 

The result includes the coefficients of the multiplication of the s-domain polynomials. As you understand that, the ‘conv()’ command is a very important command for the reductions of closed-loops or open-loops. 


The use of the ‘conv()’ command in Matlab® for the reduction of control systems is very simple like above.

Do not forget to leave your comments and questions below about the ‘conv()’ command in Matlab® below. 

If you want further coding examples about the ‘conv()’ command in Matlab®, inform us in the comments.

This article is prepared for completely educative and informative purposes. Images used courtesy of Matlab®

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