Question 11.8.12: By applying MATLAB, perform the Nyquist plots in the complex......
By applying MATLAB, perform the Nyquist plots in the complex plane of the third-order system whose transfer function is given by Equation (11.9), that is:
G(s)={\frac{5}{10s^{3}+31s^{2}+253s+\ 25}}. (11.9)
The input to and output from MATLAB are included in Program Listing 11.12a and Figure 11E12a, respectively
Script File
Program Listing 11.12a
>> num = [0 0 0 5];
>> den = [10 31 253 25];
>> nyquist(num,den)
>> title(‘Nyquist Diagram of a Third Order System’)
In order to provide a better or larger view of the plot close to the origin of the complex plane in Figure 11E12a, one would add a statement in the above MATLAB so that a closer inspection may be made. The input to and output from MATLAB are presented in Program Listing 11.12b and Figure 11E12b, respectively
Program Listing 11.12b
>> num = [0 0 0 5];
>> den = [10 31 253 25];
>> nyquist(num,den)
>> axis([−0.02 0.02 −0.03 0.03]);
>> title(‘Nyquist Diagram of a Third Order System’)
