MATLAB and Simulink Files

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MATLAB and Simulink files for textbook Nise/Controls 6e.

ch13p8.m
% Nise, N.S. 
% Control Systems Engineering, 5th ed. 
% John Wiley & Sons, Hoboken, NJ, 07030
%
% Control Systems Engineering Toolbox Version 5.0 
% Copyright  2008 by John Wiley & Sons, Inc.
%
% (ch13p8) Example 13.11:   We now use the root locus to find the gain to meet a 
% transient response requirement. After MATLAB produces a z-plane root locus, 
% along with damping ratio curves superimposed using the command zgrid, we 
% interactively select the desired operating point at a damping ratio of 0.7, 
% thus determining the gain. MATLAB responds with the gain value as well as the 
% step response of the closed-loop sampled system using step(Tz), where Tz is a 
% digital LTI transfer-function object. Let us look at Example 13.11.

'(ch13p8) Example 13.11'            % Display label.
clf                                 % Clear graph.
numgz=[1 1];                        % Define numerator of G(z).
dengz=poly([1 0.5]);                % Define denominator of G(z).
'G(z)'                              % Display label.
Gz=tf(numgz,dengz,[])               % Create and display G(z).
rlocus(Gz)                          % Plot root locus.
axis([0,1,-1,1])                    % Create close-up view.
zgrid                               % Add damping ratio curves to root 
                                    % locus.
title(['z-Plane Root Locus'])       % Add title to root locus.
[K,p]=rlocfind(Gz)                  % Allows input of K by selecting
                                    % point on graphic.
'T(z)'                              % Display label.
Tz=feedback(K*Gz,1)                 % Find T(z).
step(Tz)                            % Find step response of gain-
                                    % compensated system.
title(['Gain Compensated Step Response'])         
                                    % Add title to step response of gain- 
                                    % compensated system.

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