Direct Fuzzy Model-reference Adaptive Control of Nonlinear pH-process

| Fuzzy adaptive systems may be viewed as a framework for solving the problems of nonlinear system control. In the paper a novel model reference fuzzy adaptive control system is introduced which is based on the fuzzy model of the process. The combination of adaptive control theory based on models obtained by fuzzy basis function expansion results in fuzzy direct model-reference adaptive control which provides higher adaptation ability than basic adaptive control systems. Direct fuzzy adaptive controller directly adjust the parameter of the system to achieve arbitrary small tracking of the model-reference input. The main advantage of the proposed approach is simplicity together with high performance, and it has been proved that the closed-loop system using direct fuzzy adaptive controller is globally stable and the tracking error converges to the residual set which depends on fuzzi cation properties. In the paper the basics of the proposed algorithm are given and a simulation example on pH-process is shown and discussed. Keywords|adaptive control, fuzzy control