Performance Improvement of Non-Minimum Phase System Using IMC and FUZZY Controller

Abstract

Non-minimum phase system contains zero/zeros on the right hand side of S-Plane. When a step change or sudden change occurs in set point of non-minimum phase system, response of system first go in opposite direction then it reach at set point value. To reduce negative peak and settling IMC and Fuzzy controller has been used. IMC controller have many advantage over convention PID controller and many controllers. By using IMC it is easy to analyze effect of process characteristics such as right hand zero on over all controllability of process. Tuning of IMC controller is very easy because it has only one parameter. IMC controller has a disadvantage over disturbance rejection. It has very low capability to reduce disturbance. To remove this problem FUZZY CONTROLLER has been used. Nowadays Fuzzy controller is very popular among all controller because it works according to human experience. Fuzzy controller contains rule base. Rule base is set of rules according to which controller provides output. Designing of rule base for non-minimum phase system is very difficult. A number of Fuzzy rule base and membership functions range can be design and to find best fuzzy set is very difficult. IMC controller gives very good response for non-minimum phase system but if there is disturbance then response of system become worse. Disturbance effect on output of system is reduced by controller. By using both controller, response of system is improved in project work. 1DF IMC and 2nd DF (degree of freedom) IMC controller is also used to improve the system response. Due to non-minimum phase system IMC controller is designed by different method.1DF IMC controller response is better than 2DF IMC response. In this thesis IMC and FUZZY controller used in such a way that so we can get optimal result. For this both controller is used in various way. Some method did not provide better result. So, to improve them some modification has been done in design. In this thesis performance of Non minimum phase system has been improved by using IMC and FUZZY controller. MATLAB Simulink software is used for the simulation purpose. Designing of fuzzy controller is done by using Mamdani’s fuzzy inference method in MATLAB.