Flow Rate Control System “Frequency Response” By: Taylor Murphy March 1, 2006 U.T.C. Engineering 329

Yellow Team Jimy George Jeff Lawrence Taylor Murphy Jennifer Potter

Outline System Background –Description, SSOC, Step Response Frequency Response Experiment Frequency Response Model Results Conclusions

Flow System Setup

Block Diagram

Steady State Operation

SSOC

SSOC with Step Ranges

Experimental and Model Results K (lb/min/%) =0.26 Tau (sec) =0.46 t0 (sec) =0.42

Step Results; K

Step Results; Tau

Step Results; t 0

Frequency Response Experiment Operate with alternating frequencies Amplitude equal to 5% or 7.5% Base Power equal to center of region. Starting Frequency of 1/(tau*2*pi) Vary frequency up and down to the limits - when output is in phase with input or there is no perceptible oscillation

Sample Sine Plot

Example Experimental Bode Plots

Modeling Approach Output Function Used Excel to Model

Model Bode Plots 45%-55%

Model Bode Plots 55%-70%

Model Bode Plots 70%-85%

Model Bode Plots 85%-100%

Comparison of Results: Gain

Comparison of Results: Time Constant

Comparison of Results: Dead Time

Comparison of Results: Ultimate Frequency

Comparison of Results: Ultimate Controller Gain

Comparison of Results: Order

Conclusion FOPDT parameters from the model: K = 0.22 lbs/min/% Tau = 0.3 sec to = 0.37 sec Other values from experiment: Kcu = 10 %/(lbs/min) fu = 0.87 Hz Order = 1