Frequency Resposnse of a System: Pneumatic Air Valve

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Frequency Resposnse of a System Pneumatic Air
Valve Air Tanks

• GROUP 3 Nick Pham, Trevor Chambers, Dai Bui,
  Hien Dang

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TABLE OF CONTENTS

• Experimental Setup
• Test Plan
• Test Data
• Data Analysis
• Recommendations
• Comments, Feedback, and Suggestion

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Experimental Setup
4
Experimental Setup
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Test Plan

• Open inlet air supply
• Ensure transducer calibration
• Match gauge with computer reading
• Input in mA Output in psig ? 1mA/psig
• Select gain value for air valve control signal
• 3 mA selected
• Determine a range of frequencies to sweep that
  will provide a response to characterize the
  system.
• .01 - .30 Hz ?total of 30 runs Inlet air
  pressure 25 psig
• Each test run determine the gain, and the phase
  difference between input and output.

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Test Data
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Test Data cont.
Actual data taken from 0.01 - 0.30 Hz in
increments of 0.01
B peak trough / 2 A 3.00 Amplitude (Db)
20log(B/A) Phase shift (deg) 360 (peak to
peak shift) / (seconds per cycle)
Input test signal P(t) P0
Asin(2pft) P(t) 11 3sin(2pft)
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Data Analysis
Response suggests that system is 2nd order or
higher and overdamped Max phase lag -140
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Goodness of Model

• Can fit 2nd order overdamped model
• Peaks suggest possible resonance
• Phase lag plot not representative of standard
  response (need more data at higher frequency)

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Recommendations

• Find step response
• -fit transfer function to bode plot
• Acquire more data points on both sides of data
  set (wider range)
• If we were to use this system in industry, choose
  operating range and fit that portion only.

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Comments, Feedback, and Suggestions

• SUGGESTIONS ???