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Theory and Application of a Novel Optimal Robust Control: A Fuzzy Approach

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Abstract

A new optimal robust control is proposed for mechanical systems with fuzzy uncertainty. Fuzzy set theory is used to describe the uncertainty in the mechanical system. The desirable system performance is deterministic (assuring the bottom line) and also fuzzy (enhancing the cost consideration). The proposed control is deterministic and is not the usual if–then rules-based. The resulting controlled system is uniformly bounded and uniformly ultimately bounded proved via the Lyapunov minimax approach. A performance index (the combined cost, which includes average fuzzy system performance and control effort) is proposed based on the fuzzy information. The optimal design problem associated with the control can then be solved by minimizing the performance index. The unique closed-form optimal gain and the cost are explicitly shown. The resulting control design is systematic and is able to guarantee the deterministic performance as well as minimizing the cost. In the end, an example is chosen for demonstration.

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References

  1. Bede, B., Rudas, I.J., Fodor, J.: Friction Model by using Fuzzy Differential Equations. Foundations of Fuzzy Logic and Soft Computing, pp. 338–353. Springer, Berlin (2007)

    Google Scholar 

  2. Bezdek, J.C.: Special issue on fuzziness vs. probability—the N-th round. IEEE Trans. Fuzzy Syst. 2, 1–42 (1994)

    Article  MATH  Google Scholar 

  3. Bronshtein, I.N., Semendyayev, K.A.: Handbook of Mathematics. Van Nostrand Reinhold, New York (1985)

    Google Scholar 

  4. Chen, Y.H.: Performance analysis of controlled uncertain systems. Dyn. Control 6, 131–142 (1996)

    Article  MATH  Google Scholar 

  5. Chen, Y.H.: Fuzzy dynamical system approach to the observer design of uncertain systems. J. Syst. Control Eng. 224, 509–520 (2010)

    Google Scholar 

  6. Chen, Y.H., Leitmann, G.: Robustness of uncertain systems in the absence of matching assumptions. Int. J. Control 45, 1527–1542 (1987)

    Article  MATH  MathSciNet  Google Scholar 

  7. Corless, M.: Control of uncertain nonlinear systems. J. Dyn. Syst. Meas. Contr. 115, 362–372 (1993)

    Article  MATH  Google Scholar 

  8. Hale, J.K.: Ordinary Differential Equations. Wiley, New York (1969)

    MATH  Google Scholar 

  9. Hanss, M.: Applied Fuzzy Arithmetic: An Introduction with Engineering Applications. Springer, Berlin (2005)

    Google Scholar 

  10. Huang, J., Chen, Y.H., Cheng, A.: Robust control for fuzzy dynamical systems: uniform ultimate boundedness and optimality. IEEE Trans. Fuzzy Syst. 20(6), 1022–1031 (2012)

    Article  MathSciNet  Google Scholar 

  11. Kalman, R.E.: A new approach to linear filtering and prediction problems. Trans. ASME, J. Basic Eng. 82D, 35 (1960)

    Article  Google Scholar 

  12. Kalman, R.E.: Contributions to the theory of optimal control. Boletin de la Sociedad Mastematica Mexicana 5, 102–119 (1960)

    MathSciNet  Google Scholar 

  13. Kalman, R.E.: Randomness reexamined. Model. Identif. Control 15, 141–151 (1994)

    Article  MATH  MathSciNet  Google Scholar 

  14. Klir, G.J., Yuan, B.: Fuzzy Sets and Fuzzy Logic: Theory and Applications. Pretice-Hall, Englewood Cliffs (1995)

    MATH  Google Scholar 

  15. Lee, T.S., Chen, Y.H., Chuang, J.: Robust control design of fuzzy dynamical systems. Appl. Math. Comput. 164(2), 555–572 (2005)

    Article  MATH  MathSciNet  Google Scholar 

  16. Leitmann, G.: on one approach to the control of uncertain systems. J. Dyn. Syst. Meas. Control 115, 373–380 (1993)

    Article  Google Scholar 

  17. Li, X.P., Chang, B.C., Banda, S.S.: Robust control system design using H∞ optimization theory. J. Guid. Control Dyn. 2, 1975–1980 (1992)

    Google Scholar 

  18. McKerrow, P.J.: Introduction to Robotics. Addison-Wesley, Sydney (1991)

    Google Scholar 

  19. Schoenwald, D.A., Ozgunner, I.: Robust stabilization of nonlinear systems with parametric uncertainty. IEEE Trans. Autom. Control 39, 1751–1755 (1994)

    Article  MATH  Google Scholar 

  20. Shen, T., Tamura, K.: Robust H∞ control of uncertain nonlinear system via state feedback. IEEE Trans. Autom. Control 40, 766–768 (1995)

    Article  MATH  MathSciNet  Google Scholar 

  21. Slotine, J.E., Li, W.: Applied Nonlinear Control. Prentice Hall, Englewood Cliffs (1991)

    MATH  Google Scholar 

  22. Soong, T.T.: Active Structural Control: Theory and Practice. Longman Scientific and Technical, Essex, England (1990)

    Google Scholar 

  23. Stengel, R.F.: Optimal Control and Estimation. Dover Publications, Mineola (1994)

    MATH  Google Scholar 

  24. Utkin, V.: Sliding mode control in mechanical systems. In: 20th International Conference on Industrial Electronics, Control and Instrumentation, vol. 3, pp. 1429–1431 (1994)

  25. Xu, J., Chen, Y.H., Guo, H.: Fractional robust control design for fuzzy dynamical systems: an optimal approach. J. Intell. Fuzzy Syst. (2014). doi:10.3233/IFS-141316

    MathSciNet  Google Scholar 

  26. Zadeh, L.A.: Fuzzy sets. Inf. Control 8, 338–353 (1965)

    Article  MATH  MathSciNet  Google Scholar 

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Acknowledgments

The authors would like to express sincere thanks to National Natural Science Foundation of China No.51275147, who have supported this research work.

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Correspondence to Shengchao Zhen.

Appendix: fuzzy mathematics

Appendix: fuzzy mathematics

We briefly review some preliminaries regarding fuzzy numbers and their operations [14]:

1.1 Fuzzy number

Let G be a fuzzy set in R, the real number. G is called a fuzzy number if (i) G is normal, (ii) G is convex, (iii) the support of G is bounded, and (iv) all α-cuts are closed intervals in R.

Throughout, we shall always assume the universe of discourse of a fuzzy set number to be its 0-cut.

1.2 Fuzzy arithmetic

Let G and H be two fuzzy numbers and \( G_{\alpha } = [g_{\alpha }^{ - } ,g_{\alpha }^{ + } ] \), \( H_{\alpha } = [h_{\alpha }^{ - } ,h_{\alpha }^{ + } ] \) be their α-cuts, \( \alpha \in [0,1] \). The addition, subtraction, multiplication, and division of G and H are given by, respectively,

$$ (G + H)_{\alpha } = [\overline{g}_{\alpha }^{ - } + h_{\alpha }^{ - } ,g_{\alpha }^{ + } + h_{\alpha }^{ + } ] $$
(9.1)
$$ (G - H)_{\alpha } = [\hbox{min} (g_{\alpha }^{ - } - h_{\alpha }^{ - } ,g_{\alpha }^{ + } - h_{\alpha }^{ + } ),\hbox{max} (g_{\alpha }^{ - } + h_{\alpha }^{ - } ,g_{\alpha }^{ + } + h_{\alpha }^{ + } )] $$
(9.2)
$$ (G.H)_{\alpha } = [\hbox{min} (g_{\alpha }^{ - } h_{\alpha }^{ - } ,g_{\alpha }^{ - } h_{\alpha }^{ + } ,g_{\alpha }^{ + } h_{\alpha }^{ - } ,g_{\alpha }^{ + } h_{\alpha }^{ + } ),\hbox{max} (g_{\alpha }^{ - } h_{\alpha }^{ - } ,g_{\alpha }^{ - } h_{\alpha }^{ + } ,g_{\alpha }^{ + } h_{\alpha }^{ - } ,g_{\alpha }^{ + } h_{\alpha }^{ + } )] $$
(9.3)
$$ (G / H)_{\alpha } = [\hbox{min} (g_{\alpha }^{ - } /h_{\alpha }^{ - } ,g_{\alpha }^{ - } /h_{\alpha }^{ + } ,g_{\alpha }^{ + } /h_{\alpha }^{ - } ,g_{\alpha }^{ + } /h_{\alpha }^{ + } ),\hbox{max} (g_{\alpha }^{ - } /h_{\alpha }^{ - } ,g_{\alpha }^{ - } /h_{\alpha }^{ + } ,g_{\alpha }^{ + } /h_{\alpha }^{ - } ,g_{\alpha }^{ + } /h_{\alpha }^{ + } )]. $$
(9.4)

1.3 Decomposition theorem

Define a fuzzy set \( \tilde{V}_{\alpha } \) in U with the membership function \( \mu_{{\tilde{V}_{\alpha } }} = I_{{\tilde{V}_{\alpha } }} (x), \) where \( I_{{\tilde{V}_{\alpha } }} (x) = 1 \) if \( x \in \tilde{V}_{\alpha } \) and \( I_{{\tilde{V}_{\alpha } }} (x) = 0 \) if \( x \in U - \tilde{V}_{\alpha } \). Then the fuzzy set V is obtained as

$$ V = \bigcup\limits_{\alpha \in [0,1]} {\tilde{V}_{\alpha } }, $$
(9.5)

where \( \cup \) is the union of the fuzzy sets (that is, sup over \( \alpha { \in }[0,1] \)).

Based on these, after the operation of two fuzzy numbers via their α-cuts, one may apply the decomposition theorem to build the membership function of the resulting fuzzy number.

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Zhang, K., Han, J., Xia, L. et al. Theory and Application of a Novel Optimal Robust Control: A Fuzzy Approach. Int. J. Fuzzy Syst. 17, 181–192 (2015). https://doi.org/10.1007/s40815-015-0026-3

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  • DOI: https://doi.org/10.1007/s40815-015-0026-3

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