Disturbance Observer Based Discrete Sliding Mode Controller for Linear Reluctance Actuator

The magnetoresistance effect is a promising approach for designing high-force density actuators, but its strong nonlinearity limits its application in nano-positioning systems. In this study, a Hammerstein configuration is employed to characterize the rate-dependency of the reluctance actuator. Furthermore, a novel control approach was introduced that integrates inverse model compensation with the discrete sliding mode control using disturbance observer. This innovative strategy demonstrates remarkable efficacy in mitigating the impact of hysteresis phenomenon. What’s more, the discrete sliding mode controller based on disturbance observer improves tracking performance and robustness under parameter variations of model and external disturbances. The results indicate that, with inverse compensator, the novel control method can achieve 1.26% flux density tracking accuracy, which demonstrates superiority over both the PI controller and the discrete sliding mode controller, thereby validating its effectiveness in mitigating hysteresis.