A neuro-fuzzy-sliding mode controller using nonlinear sliding surface applied to the coupled tanks system
- 301 Downloads
The aim of this paper is to develop a neuro-fuzzy-sliding mode controller (NFSMC) with a nonlinear sliding surface for a coupled tank system. The main purpose is to eliminate the chattering phenomenon and to overcome the problem of the equivalent control computation. A first-order nonlinear sliding surface is presented, on which the developed sliding mode controller (SMC) is based. Mathematical proof for the stability and convergence of the system is presented. In order to reduce the chattering in SMC, a fixed boundary layer around the switch surface is used. Within the boundary layer, where the fuzzy logic control is applied, the chattering phenomenon, which is inherent in a sliding mode control, is avoided by smoothing the switch signal. Outside the boundary, the sliding mode control is applied to drive the system states into the boundary layer. Moreover, to compute the equivalent controller, a feed-forward neural network (NN) is used. The weights of the net are updated such that the corrective control term of the NFSMC goes to zero. Then, this NN also alleviates the chattering phenomenon because a big gain in the corrective control term produces a more serious chattering than a small gain. Experimental studies carried out on a coupled tank system indicate that the proposed approach is good for control applications.
KeywordsSliding mode fuzzy logic neural networks coupled tanks system
Unable to display preview. Download preview PDF.
- S. V. Emel’yanov. Variable Structure Control Systems, Nouka, Moscow, 1967.Google Scholar
- F. Boudjema, J. L. Abatut. Sliding-Mode: A New Way to Control Series Resonant Converters. In Proceedings of IEEE Conference Industrial Electronics Society, IEEE Press, Pacific Grove, Florida, USA, vol. 2, pp. 938–943, 1990.Google Scholar
- D. Boukhetala, F. Boudjema, T. Madani, M. S. Boucherit, N. K. M’sirdi. A New Decentralized Variable Structure Control for Robot Manipulators. International Journal of Robotics and Automation, vol. 18, no. 1, pp. 28–40, 2003.Google Scholar
- M. Ertugrul, O. Kaynak, A. Sabanovic, K. Ohnishi. A Generalized Approach for Lyapunov Design of Sliding Mode Controllers for Motion Control Applications. In Proceedings of the 4th IEEE International Workshop on Advanced Motion Control, IEEE Press, Mie University, Japan, pp. 407–412, 1996.CrossRefGoogle Scholar
- P. Wellstead. TecQuipment CE105 Coupled Tanks Apparatus, Control Systems Centre, Manchester, UK, 1993.Google Scholar
- J. J. Slotine, W. Li. Applied Nonlinear Control, Prentice Hall, 1991.Google Scholar
- N. Yeganefar, M. Dambrine, A. Kokosy. Stabilisation pratique par modes glissants pour un système linéaire à retard. In Proceedings of Conférence Internationale Francophone D’Automatique, Tunisia, CD-ROM, 2004. (in French)Google Scholar
- M. Ertugrul, O. Kaynak. Neural Computation of the Equivalent Control in Sliding Mode for Robot Trajectory Control Applications. In Proceedings of IEEE International Conference on Robotics and Automation, Belgium, vol. 3, pp. 2042–2047, 1998.Google Scholar
- J. Z. Liu, W. J. Zhao, L. J. Zhang. Design of Sliding Mode Controller Based on Fuzzy Logic. In Proceedings of the 3rd IEEE Conference on Machine Learning and Cybernetics, IEEE Press, Shanghai, PRC, pp. 616–619, 2004.Google Scholar