MODIFIED FUZZY GAIN SCHEDULING OF PID CONTROLLERS. B.HEMAKUMAR. OBJECTIVES. To obtain responses for various SISO processes using fuzzy gain scheduling of PID controller and to compare this with conventional PID controller response.
DESIGN OF FUZZY GAIN SCHEDULING OF PID CONTROLLERS
This scheme utilities fuzzy rules and reasoning to determine the controller parameters for PID controller to generate the control signals.
WORKING RANGE FOR Kp AND Kd
Kc,min = 0.4Ku; Kc,max = 0.55Ku
Kd,min = 0.09KuTu; Kd,max = 0.16KuTu
For fuzzy set small,
μsmall (x) = - ¼ ln(x) or xsmall (μ) = e-4µ
For fuzzy set big,
μbig (x) = - ¼ ln(1 - x) or xbig (μ) = 1 - e-4µ
Based on µi, the values of Kc’ and Kd’ for each rule are determined from their corresponding membership functions.