Fuzzy Adaptive Active Control Isolator

The vibration phenomenon is inevitable for some mechanical systems. In order to reduce the invalid influence on the stability of systems, isolator is used to isolate the transmission of mechanical vibration. The control technology of the active vibration isolation is proposed according to the mathematical model of the controlled object and the performance requirements. And the corresponding controlling rules are described mathematically. However, there always exists considerable complexity in real systems due to system’s inherent nonlinearities, model uncertainty and time-varying parameters. That shows why it is difficult to design an effective and simple mathematical model. This paper focuses on the problem of vibration control to propose a new method of designing an adaptive fuzzy controller. The method of isolating vibration source is used to set up the dynamic model for active vibration. Fuzzy logical systems are utilized to approximate these unknown nonlinear functions, meanwhile, backstepping and adaptive fuzzy control technique are employed to construct a controller. The main content of the thesis are listed as follows:Part1:Adaptive fuzzy control of a class of nonlinear uncertain systemsThis part mainly considers adaptive fuzzy control problem of a class of nonlinear single-input/single output (SISO) strict-feedback systems. Fuzzy logic systems are used to approximate the unknown nonlinear functions, and then classical adaptive technique associated with backstepping are used to design the fuzzy adaptive controller. The simulation results illustrate that the proposed adaptive fuzzy controller ensures all the signals of the closed-loop system are uniformly ultimately bounded.Part2:Adaptive fuzzy control of an active vibration isolatorThis part mainly focuses on stabilization of an active vibration with uncertainties. By using the method of isolating vibration source, the dynamic model is established for active vibration. Fuzzy logical systems are used to approximate these unknown nonlinear functions, meanwhile, backstepping and adaptive fuzzy control technique are utilized to construct an adaptive fuzzy controller. The simulation results illustrate that all the state variables of the system can quickly converge to a small neighborhood of the origin under the action of the proposed controller. It is shown that the proposed fuzzy adaptive controller not only stabilizes the active isolator system but also keeps all of the adaptive signals bounded. The approach developed in this paper ensures that the active vibration isolation system has a good performance of vibration isolation.