Non-contact measurement technique for horizontal force perturbations in magnetic levitation systems

Abstract Accurate measurement of small forces on large objects under experimental laboratory conditions is challenging due to the limited sensitivity of available instruments and adaptable methods. For example, in wind tunnel testing for aerodynamic performance, the generation of very small lift or drag forces on the test object often proves difficult to quantify. Recent advancements in maglev technology have led to its application in wind tunnel studies, where it is used to mitigate the interference on measurements caused by support systems. However, the accuracy of measurements may be compromised due to systemic errors affecting the performance of force sensors in the wind tunnel, such as mechanical vibrations, misalignments, and contact deformations. To address these issues in the measurement of small forces during wind tunnel experiments, this paper proposes a contactless method for measuring small horizontal forces based on current variation in the levitation coil, which can be generally applied in maglev systems. To investigate and understand the changes in the coil with applied control system, a coil-to-permanent-magnet maglev model with applied horizontal force has been developed and studied. Both software simulations and experimental validations are used to ensure the validity of the proposed method.