Predictive fuzzy PID control: Theory, analysis and applications.
详细信息
文摘
Predictive fuzzy PID control theory is developed in this dissertation, which offers a new approach for robust control of time-delay systems. The dissertation describes the functional structure, design principle, and stability analysis of a new predictive fuzzy PID controller, along with sufficient computer simulations and a real-world application in laser coagulation measurement and control.;First, the structure of the controller is derived from both the fuzzy PID controller and the generalized predictive control concepts. A particular type of PID controller, called PD+I controller is studied. Then on-line model identification, optimal cost index, fuzzification, rule base and defuzzification of the representative predictive fuzzy PD+I controller are discussed in detail.;After the Lyapunov asymptotic stability analysis is completed, many computer simulations are performed and compared to several closely related controllers such as the fuzzy PD+I controller and the Smith-type predictive fuzzy PD+I controller. In the simulations, second-order linear systems with/without time delays, nonlinear systems with/without time delays, uncertain linear systems with time delays, and uncertain nonlinear systems with time delays are used to confirm the advantages of the new predictive fuzzy PD+I controller. Finally, this method is applied to control some chaotic systems with success. The dissertation, thus, provides new ways for controlling uncertainty and complex linear and nonlinear systems with time delays.;In the dissertation, as a real-world application, a new design of a fuzzy PD controller (which is the main component of the PD+I controller) is also presented for the Nd:YAG laser coagulation of liver cancer in vitro. Real-time control experimental results obtained from a laboratory of the University of Texas Medical Branch at Galveston are reported. The designed system is unique, as it is the first laser coagulation control system that is guided by noninvasive measurement and controlled by fuzzy PD controller in real-time. This work establishes the feasibility for real-time feedback control of laser therapy.