www.gusucode.com > robust 案例源码程序 matlab代码 > robust/SensitivityToUncertainElementsExample.m
%% Sensitivity to Uncertain Elements % Examine the relative sensitivity of the robust stability margin to the uncertain % elements of the system. Consider a model of a control system containing % uncertain elements. %% k = ureal('k',10,'Percent',40); delta = ultidyn('delta',[1 1]); G = tf(18,[1 1.8 k]) * (1 + 0.25*delta); C = pid(2.3,3,0.38,0.001); CL = feedback(G*C,1); %% % Create an options set for |robstab| that enables the sensitivity calculation. opts = robOptions('Sensitivity','On'); %% % Calculate the robust stability margin, specifying the |info| output to % access additional information about the calculation. [stabmarg,wcu,info] = robstab(CL,opts); %% % Examine the |Sensitivity| field of |info|. info.Sensitivity %% % The values in this field indicate how much a change in the normalized % perturbation on each element affects the stability margin. For example, % the sensitivity for |k| is 21. This value means that a given change |dk| % in the normalized uncertainty range of |k| causes a change of about 21% % percent of that, or |0.21*dk|, in the stability margin. The margin in % this case is much more sensitive to |delta|, for which the margin changes % by about 81% of the change in the normalized uncertainty % range.