Near-zero-vibration non-contact transportation by single-body decoupled 2-DOF magnetic levitator for multi-size targets with unknown mass

This paper presents a near-zero-vibration control (NZVC) method to significantly reduce the inertial disturbance for high-throughput non-contact transportation of multi-size levitated targets with unknown mass using a single-body 2-DOF magnetic levitation actuator. The proposed NZVC method is composed of two key components: (1) a parameter estimation algorithm designed to identify the target size with unknown mass and the associated changes in system dynamics, and (2) an adaptive feedforward controller, capable of compensating for inertial disturbances in the levitated targets during high-acceleration transportation. The proposed parameter estimation algorithm, which is based on the comprehensive system model that integrates the magnetic levitation actuator and the fiber optical sensor, enables accurate estimation of the size of the targets with an error of less than 1$\text{\%}$. The NZVC method, combined with an adaptive feedforward controller, achieves a maximum of 87.4$\text{\%}$ and 52.2$\text{\%}$ reduction in the target vibration and accumulated energy consumption by decreasing the current required to compensate for the undesired vibration from inertial disturbances during high-throughput non-contact transportation.