Stability analysis and suppression control of rotor oscillation for stepping motors by Lyapunov´s direct method

Stepping motors are used as the driver for positioning in control systems. It is well-known that the transient response of a stepping motor is generally oscillatory in the case of open-loop control. The rotor oscillation must be suppressed in quick positioning applications. In this paper, the stability analysis and the suppression control of rotor oscillations of variable reluctance stepping motors are studied by Lyapunov´s direct method. Since the motor is a nonlinear system, the method is useful for analyzing the stability of the motor. The suppression control of rotor oscillations is achieved by excitation control of phase windings using the Lyapunov function. The validity of this method is examined by experiments