OFF-AXIS MAGNETIC ANGULAR SENSOR USING A MAGNETIC SENSING PROBE AND MULTI-POLE MAGNET ARRAY

• Main Authors: ANDREWS, Richard, KENNEY, Christopher, SCHWEIZER, Pascal
• Format: Patent
• Language: English; French; German
• Published: 22.02.2023
• Subjects: ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVEREDIN A SINGLE OTHER SUBCLASS; MEASURING; MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR; PHYSICS; TARIFF METERING APPARATUS; TESTING

A position measurement system for measuring the position of a movable device versus a fixed device, the position measurement system comprising: a two-dimensional (2D) surface magnet array with at least three adjacent magnetized tracks having sequentially alternating magnetic polarities, each magnetized track having a constant width w; and at least one magnetic field sensor disposed proximate to, and maintaining a constant airgap with respect to, the 2D surface magnet array, wherein an airgap distance between the at least one magnetic field sensor and the 2D surface magnet array is between w/2 and w/4 to minimize signal distortion, wherein the 2D surface magnet array and the at least one magnetic field sensor are in a specific relative orientation such that a relative trajectory of the at least one magnetic field sensor is configured to be at a tilted, acute angle θ with respect to a length direction of the at least three adjacent magnetized tracks of the 2D surface magnet array, wherein in response to relative movement along the relative trajectory, the at least one magnetic field sensor is configured to generate a periodic position signal having a period Pθ that depends, at least in part, upon the width w and the tilted, acute angle θ according to the equation: Pθ=awcosθ,witha=1ora=2.