Ziegler-Nichols-criteria

MATLAB calculation details and plots can be found on our Web Support. You should observe that Cohen-Coon and Ziegler-Nichols tuning relations lead to roughly 74% and 64% overshoot, respectively, which are more significant than what we expect with a quarter decay ratio criterion. 

IV.66 Repeat Problem IV. 39 but use the Ziegler-Nichols tuning technique instead of the ISE criterion. Compare the Ziegler-Nichols settings found here with those found in Problem IV. 39. 

Perhaps the most well known and most frequently published method is that by Ziegler and Nichols (Reference 3). They developed an open loop method in addition to the more frequently published closed loop method. The criterion used by both methods is the quarter decay ratio. This is illustrated in Figure 3.21 following a SP change the PV response should be slightly oscillatory with the height of the second peak being one-quarter of that of the first. 

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