Simplified Position Estimation Using Back-EMF for Two-DoF Linear Resonant Actuator

This paper proposes a simplified position estimation method and clarifies the dynamic characteristics of the two-degree-of-freedom (DoF) resonant actuator under sensorless control. The feature of this two-DoF actuator is that movement in the x- and z-axis can be independently controlled by vector control. In this paper, we extrapolate the mover position from the zero crossing time and amplitude of the back electromotive force. During both single and biaxial drives, it was found that the amplitude of the x- and z-axis could be independently controlled without using position sensors. The measured results agree well with the analyzed results. From these results, the effectiveness of the proposed estimation method was verified.