Matlab Implementation of Position Control of a Hybrid Stepper Motor Using Fuzzy Logic Controller

Abstract

Hybrid Stepper Motors (HSMs) have received enormous industrial applications due to their higher efficiency, better resolution, better detent torque and smoother operation as compared to other stepper motors and servomotors. HSM conventional control schemes however could not overcome poor damping characteristics at increasing load inertia, high overshoot, undershoot and settling time which compromise motor integrity in terms of efficiency and precise positioning. In this paper, a PI-based Mamdani type Fuzzy Logic Controller (FLC) was designed for an HSM. Triangular and trapezoidal membership functions for input and output linguistic variables were employed giving 49 rules in the rule base of the FLC. Matlab fuzzy logic toolbox was used for the FLC design. The FLC was used to model a position controller for the HSM in Simulink. The dynamic response for a unit step input for the HSM position control system presented better characteristics in terms of overshoot and undershoot but higher settling time and rise time as compared to the system without FLC. With the FLC, overshoot and undershoot were 0.454% and 1.892% as against 0.562% and 4.069% for the non-FLC respectively. The settling time and rise time were 15.36 ms and 9.83 ms for the FLC as against 13.727 ms and 5.306 ms for the non-FLC respectively. Further, the FLC response had almost no ripples. The FLC could be considered for the control of the HSM.