# HW 7 Prob 1 Comments

For Problem 1c you need to design two controllers. The first one is designed using the Ziegler-Nichols rules for the step response method. You need to plot the step response of the closed-loop and the frequency response of the loop transfer function L. Then you are asked to design a controller using the Ziegler-Nichols rules for the frequency response method. You also need to plot the step response of the closed-loop and the frequency response of the loop transfer function L (this is what is in the solutions). Both the step response method and frequency response method rules are found in table 10.1 on pg. 301.

Remember that when you use the step-response Ziegler-Nichols method, you need to plot the unit step response for the plant. You must draw the steepest tangent line to the step response until it crosses the two axes. You can then approximate the values for "a" and "tao" by visual or numerical approximation.
As usual for all HW questions, give a title to your plots, label axes, and turn in code along with your plots.
--Soto 14:20, 25 November 2007 (PST)