A Study On Adaptive Fuzzy Control Of A Class Of Three-Species Food Chain

In this paper,we study a class of three-species food chain systems with functional response function.Based on the mathematical models we have established for the food chain systems,we combine the fuzzy control theory and the ecosystem theory and then study the application of fuzzy control method in food chain systems,which helps us establish an effective stable control method for ecosystem.Chapter one introduces the background and actuality of the study and the primary conclusion of this article.Chapter two introduces some basic fuzzy control theories and how to design a direct adaptive fuzzy controllor.In Chapter three,based on a three-species food chain system advanced by Hastings and Powell,considering that the phytoplankton can release toxin which can affect the number of fish indirectly,so in order to realize the biological control and maintain the ecology balance we introduced fuzzy control method to construct the adaptive feedbacking controller by Lyapunov synthetic analysis method.The control problem of three-species food chain system was studied after the adaptive algorithm was presented.At last the simulation results demonstrated the feasibility and effectiveness of this kind of adaptive controller.In Chapter four,taking a three-specise food chain system with Hollingâ…£functional response function for an example,we found fuzzy dynamic model and construct an adaptive fuzzy controller by fuzzy logic.In order to overcome the complexities came from the outer environment,the supervisory controller was added as a compensatory controller which makes the adaptive fuzzy controller steady.All the uncertain parameters can be adjusted using the adaptive law which can be got by Lyapunov stability theory and make practical output track ideal output.At last the simulation results demonstrated the effectiveness of this method.