“Purely” analog “truly” fractional control of the coupled tank system

1. “Purely” analog “truly” fractional control of the coupled tank system Shayok Mukhopadhyay, Calvin Coopmans CSOIS, Department of Electrical & Computer Engineering, Utah State University FOC Literature reading group

2. The actual coupled tank system FOC Literature reading group

3. A schematic of the system FOC Literature reading group

4. Sensor Calibration FOC Literature reading group

5. Sensor Calibration – contd. • The sensors for this system are very noisy and a bit non-linear. • Hence good calibration is very essential. • The method for calibration consists of choosing finite number of points in the range of operation, noting the corresponding output voltage and interpolating the voltage for points in between. • With increase in the number of points, the accuracy increases. • The Simulink ‘Look up table’ block can be used to perform interpolation at run time. FOC Literature reading group

6. Schematic of the analog PID/FOPID controller board FOC Literature reading group

7. Board Layout FOC Literature reading group

8. Actual Board FOC Literature reading group

9. System Layout FOC Literature reading group

10. Prize winning Op-Amps TLV 2774i *Courtsey of TI.com FOC Literature reading group

11. Ziegler-Nichols tuning • For the traditional PID control, Ziegler-Nichols tuning rules are used. • Relay auto-tuning provides the gains required for the system. FOC Literature reading group

12. Results of ZN-PID control FOC Literature reading group

13. Results of ZN-PID control.. FOC Literature reading group

14. Results of ZN-PID control… FOC Literature reading group

15. Fractors… • We have 10 of these devices with the following specifications FOC Literature reading group

16. Finding the order..? (Fractor #8) Magnitude=-α*20dB/Decade FOC Literature reading group

17. Experimental results… FOPID control FOC Literature reading group

18. Experimental results… FOPID control FOC Literature reading group

19. Experimental results… FOPID control FOC Literature reading group

20. Experimental results… FOPI control FOC Literature reading group

21. Experimental results… FOPI control FOC Literature reading group

22. Experimental results… FOPI control FOC Literature reading group

23. Comparison…1 FOC Literature reading group

24. Comparison…2 FOC Literature reading group

25. Comparison…3 FOC Literature reading group

26. Conclusions • PID control with ZN tuning rules shows slow response, oscillations and some steady state error. • Experimentally tuned FOPI/FOPID controllers are a bit faster, show no oscillations and error is almost zero. • Control effort for FOPI/FOPID controllers is lower than corresponding ZN-PID controllers. • Using tuning algorithms for determining FOPI parameters should show better results as observed in simulations. • “Purely” Analog control is much faster and better than ‘hybrid’ or partly digital control done by using computers in a hardware in loop setting. FOC Literature reading group

27. Future work • Using earlier work to attain correct orders and gains. • Finding a way to approximate the order by using a collection of ‘Fractors’ of other orders available. • Simulating / Real life testing to see how well it works. FOC Literature reading group

28. Acknowledgements… • Cal Coopmans – For helping in board design and construction. • Austin Jensen – Thanks for helping in the milling process. FOC Literature reading group

29. References • http://mechatronics.ece.usu.edu/ece5320/Schedule/ClassNotes/W13_PID_ra_ECE5320.zip • www.mathworks.com • www.ti.com • http://www.ecircuitcenter.com/Circuits/op_pid/op_pid.htm FOC Literature reading group

30. Questions..? FOC Literature reading group