Optimized fuzzy logic for motion control

Abstract

For any fuzzy logic application the first and foremost task is to select the optimum number and shape of membership functions such as bell shape, singleton, triangular, etc. for fuzzification; then it is equally essential to select the appropriate defuzzification method, such as COG, COM, MOM, etc. The sampling rate to execute the given command is another important parameter. If these three parameters are optimally selected then the output response of motion controller will have a shorter rise time, less settling time, minimized overshoots/undershoots and negligible steady state error. Hence, the systematic study on selection of number and shape of membership function, selection of defuzzification methods and sampling time for speed control of PMDC micro motor is studied experimentally by applying LabVIEW software. The experimental results reveal that 7 numbers of triangular membership functions, COG defuzzification method and 1 millisecond (msec) sampling rate for labVIEW program execution are the optimum parameters for motion control.