PItuningapp

Here you can run a javascript app, or download an app for Android for tuning PI controllers based on the open loop step response of the plant.

 It requires the user to introduce some measurements obtained from an open loop step experiment in the plant. For minimum phase systems, the measurements are:

• The final output value, to calculate the static gain, K.

• The times that takes the output to reach, the 5%, the 35.3%, and the 85.3% of the final value.

For non minumum phase systems, more measurements are needed:

• The time and value of the minimum point of the inverse oscillation.

• The time to reach the 0 value, instead of the time to reach the 5%.

For minimum phase systems, with those measurements, the application computes an approximate model with three real poles and a time delay defined by parameters : K, tau, L and alpha. 

For non minimum phase systems, with those measurements, the application computes an approximate model with three real poles, a positive zero and a time delay defined by parameters : K, tau, L, beta and alpha. 

The desired robustness is then selected by the user introducing the value of Ms (through a slider or a numeric input). Finally, the user can select the desired detuning factor (gamma<1). For gamma=1, the optimum PI controller is obtained (the one that minimizes the disturbance IAE). For lower values of  gamma  one obtains slower PI controllers with the same robustness. The application shows the performance indicator IE=1/Ki, and the high frequency noise amplification, Kp, to guide in the selection of detuning parameter. The expected response to a step change in the reference and to a step input disturbance is also shown. 

FILE DOWNLOAD (for minimum phase only):

PItuning.apk

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