Relay Feedback Based Improved Critical Point Estimation for Process Control Systems

  • D. Simhachalam
  • S. Talukder
  • R. K. Mudi
Part of the Communications in Computer and Information Science book series (CCIS, volume 250)


Relay feedback auto-tuning test is used for estimation of critical point i.e. ultimate gain and ultimate period for designing process control systems. An experimental technique is proposed for improved estimation of the critical point by conducting the relay feedback test for two different hysteresis bands. Simulation results show that the critical point estimation by our proposed method is superior to standard relay feedback method, and very close to the actual one. Usefulness of the proposed method is demonstrated through close-loop control performance for both set-point change and load disturbance.


Process Control System Internal Model Control Load Disturbance Controller Tuning Relay Feedback 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. 1.
    Astrom, K.J., Hagglund, T.: PID controller: Theory, Design and Tuning, USA. Instru ment Society of America (1995)Google Scholar
  2. 2.
    Dey, C., Mudi, R.K.: An improved auto-tuning scheme for PID controllers. ISA Transactions 48(4), 396–409 (2009)CrossRefGoogle Scholar
  3. 3.
    Astrom, K.J., Hagglund, T.: Revisiting the Ziegler-Nichols step response method for PID control. Journal of Process Control 14(6), 635–650 (2004)CrossRefGoogle Scholar
  4. 4.
    Ziegler, J.G., Nichols, N.B.: Optimum settings for automatic controllers’. ASME Transactions 64, 759–768 (1942)Google Scholar
  5. 5.
    Astrom, K.J., Hagglund, T.: Automatic Tuning of Simple Regulators with Specifications on Phase and Amplitude Margins’. Automatica 20, 645–651 (1984)MathSciNetCrossRefzbMATHGoogle Scholar
  6. 6.
    Lee, T.H., Wang, Q.G., Tan, K.K.: A modified relay based technique for improved critical point estimation in process control. IEEE Transactions on Control Systems Tech. 3(3), 330–337 (1995)MathSciNetCrossRefGoogle Scholar
  7. 7.
    Sung, S.W., Park, J.H., Lee, I.: Modified relay feedback method. Industrial Engineering and Chemistry Research 34(11), 4133–4135 (1995)CrossRefGoogle Scholar
  8. 8.
    Shen, S., Yu, H., Yu, C.C.: ‘Use of the saturation relay feedback for autotune identification. Chem. Eng. Sci. 51(8), 1187–1198 (1996)CrossRefGoogle Scholar
  9. 9.
    Wang, Q.G., Hang, C.C., Zou, B.: Low-Order Modeling from Relay Feedback. Industrial Engineering and Chemistry Research 36(2), 375–381 (1997)CrossRefGoogle Scholar
  10. 10.
    Choudhury, D.R.: Modern Control Engineering. Prentice Hall of India, New Delhi (2006)Google Scholar
  11. 11.
    Mudi, R.K., Dey, C., Lee, T.T.: An improved auto-tuning scheme for PI controllers. ISA Transactions 47(1), 45–52 (2008)CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  • D. Simhachalam
    • 1
  • S. Talukder
    • 1
  • R. K. Mudi
    • 1
  1. 1.Dept. of Instrumentation & Electronics EnggJadavpur UniversityKolkataIndia

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