| In recent years,people have gradually realized the importance of protecting the ecological environment.In some of the latest research and reports,it can be seen that many biological species have been affected by soil erosion and the living environment has been destroyed,resulting in a continuous reduction in species density,and species even in a vulnerable state.In practice,the population density of organisms will also be disturbed by various factors,such as the influence of living space,natural enemies,climate,and food.For the influence of these completely unknown factors on species density,it is also necessary to seek solutions.Therefore,there is an urgent need to track biological population densities by proposing a control scheme.This thesis applies the adaptive control to the biological system to solve the tracking control problem of the biological population density,and the biological system finally reaches the stability.In this thesis,focusing on the biological system with stage structure.The tracking control problem of biological population density is studied by combining adaptive control,fuzzy system theory and fuzzy logic system.The main research work is as follows:(1)The adaptive tracking control of biological system with stage structure based on T-S fuzzy observer is studied.First,a biological model with a stage structure is established to analyze its stability at equilibrium points.Considering the impact of human activities on population density,an adaptive controller is applied to the system.Since the density of biological populations is difficult to measure directly,a fuzzy state observer is designed to estimate the density of biological populations.Then,under the adjustment of the designed adaptive controller,the density of the predator can track the given desired density,which ensures the stability of the biological system,and makes both the observer error and the tracking error converge to zero.Finally,the effectiveness of the proposed adaptive control method is verified by numerical simulation.(2)The adaptive fuzzy tracking control of stochastic biological systems with stage structure is studied.For biological systems with stage structure,considering the influence of external uncertain factors on biological populations,fuzzy logic systems are introduced to approximate these unknown nonlinear terms.By defining a suitable Lyapunov function and combining the backstepping method with adaptive fuzzy control,an adaptive fuzzy controller is designed.Applying the controller to the prey-predator model ensures that the juvenile population density of the prey can track a given density and that the tracking error converges to a neighborhood of zero,while all states in the biological system are semi-globally consistent eventually bounded.Finally,we verify the effectiveness of the designed control scheme in biological control problems through numerical simulations,and highlight the advantages of the proposed scheme through comparison with existing adaptive schemes. |
