Identify Delay Using Transient-Response Plots

You can use transient-response plots to estimate the input delay, ordead time, of linear systems. Input delay represents the time it takes for the output to respond to the input.

In the System Identification app: To view the transient response plot, select theTransient respcheck box in the System Identification app. For example, the following step response plot shows a time delay of about 0.25 s before the system responds to the input.

At the command line: You can useimpulseplotto plot the impulse response. The time delay is equal to the first positive peak in the transient response magnitude that is greater than the confidence region for positive time values.

For example, the following commands create an impulse-response plot with a 1-standard-deviation confidence region:

loaddry2ze = dry2(1:500); opt = impulseestOptions('RegularizationKernel',“TC”); sys = impulseest(ze,40,opt); h = impulseplot(sys); showConfidence(h,1);

The resulting figure shows that the first positive peak of the response magnitude, which is greater than the confidence region for positive time values, occurs at 0.24 s.

Instead of usingshowConfidence, you can plot the confidence interval interactively, by right-clicking on the plot and selectingCharacteristics>Confidence Region.

Related Topics

• 估计使用系统脉冲响应模型Identification App
• Estimate Impulse-Response Models at the Command Line