Plot in Fig 12.6(b) looks slightly incorrect

[Adrian Ong]

This item specifically refers to: Version v3.0i (2018-11-11), Example 12.3, Figure 12.6, pg. 12-12.

I used maxima & the COMA toolbox to plot the step response and magnitude response for P(s), C(s) as given in Example 12.3. The plots for Guw look slightly different from what's in the book.

kp : 0.6; ki : 0.5; kd : 2.0; Tf : 0.1; P : 1/(s+1)^3; C : (kds^2+kps+ki) / s/(s^2Tf^2/2 + sTf + 1); T : PC; Gyv : P/(1+T); Guw : C/(1+T); /step_response(Gyv, xrange=[0,20]);/ step_response(Guw, xrange=[0,2]); /magnitude_plot(Gyv, xrange=[0.1, 10], yrange=[10^-2, 1]);*/ magnitude_plot(Guw, xrange=[0.1, 100], yrange=[.1, 100]);

[Richard Murray]

Fixed in commit d854313. Parameters in the text were incorrect. They should have been

kp = 2.0;
ki = 1.5;
kd = 2.0;
Tf = 0.1;

[Richard Murray]

Fixed.