Modelling and characteristic analysis of a displacement sensor with liftoff compensation

摘要

Purpose - The purpose of this paper is to present a magnetic contactless displacement sensor with liftoff compensation. The sensor consists of two-axis Hall sensor, moving permanent magnet (PM) and ferromagnetic substrate which is considered as a magnetic flux concentrator. Design/methodology/approach - The two Hall-effect sensors are used to detect the B_X and B_Y induced by the moving PM. The B_X and BY curves reflect the nature of the liftoff and the displacement of the inducing PM, respectively. Then the model of the displacement sensor, based on the facing current method, is constructed. Finally, the finite element method is used to compute the characteristics of B_X and B_Y. Findings - The B_Y curve can be corrected according to the liftoff distance of Hall-effect sensor distinguished by the B_X trough value. Therefore, the influence of the liftoff on the output signal can be eliminated when B_Y curve is corrected. Originality/value - The paper focused on the design of a contactless displacement sensor with compensated liftoff performance for the control measurement technology in general and for automotive engineering in particular.