Comparison of Three Nonlinear Control Methods for a Permanent Magnet Stepper Motor

This study compares three nonlinear control methods, Feedback Linearization, Sliding Mode Control, and Backstepping, applied to a Permanent Magnet Stepper Motor. Stepper motors are widely used in precision applications, but their nonlinear nature makes control challenging. This study implements and evaluates each method's performance based on the accuracy of motor position and angular velocity, phase currents, and control inputs. The analysis shows that each control strategy has distinct advantages. Sliding mode controller provides robustness to uncertainties but suffers from chattering, feedback linearization achieves precise control but is sensitive to disturbances, and backstepping demonstrates global asymptotic stability without any additional transformation. Simulations illustrate that the backstepping controller provides the most efficient control with lower input voltage requirements.