Two-Dimensional Inductive Position Sensing System

摘要

A two-dimensional inductive position sensing system uses four drive inductors arranged at the vertices of a parallelogram and a sensing inductor positioned within the parallelogram. The sensing inductor is movable within the parallelogram and relative to the drive inductors. A first oscillating current at a first frequency is supplied to a first pair of the drive inductors located at ends of a first diagonal of the parallelogram. A second oscillating current at a second frequency is supplied to a second pair of the drive inductors located at ends of a second diagonal of the parallelogram. As a result, the sensing inductor generates a first output voltage at the first frequency and a second output voltage at the second frequency. A processor determines a position of the sensing inductor relative to the drive inductors using the first output voltage and the second output voltage.

主权项

1. An inductive position sensing system, comprising:
four drive inductors, each of said drive inductors having an axial core, said drive inductors arranged at vertices of a parallelogram wherein said axial core for each corresponding one of said drive inductors is located at one of said vertices; a sensing inductor having an axial core, said sensing inductor positioned within said parallelogram wherein said axial core of said sensing inductor is parallel to each said axial core of said drive inductors; each of said drive inductors and said sensing inductor being a mechanically independent inductor structure; said drive inductors and said sensing inductor immersed in a common medium wherein said drive inductors and said sensing inductor are inductively coupled through said common medium; said sensing inductor being movable within said parallelogram and relative to said drive inductors wherein said axial core of said sensing inductor remains parallel to each said axial core of said drive inductors; sources for supplying a first oscillating current at a first frequency to a first pair of said drive inductors located at ends of a first diagonal of said parallelogram, and for supplying a second oscillating current at a second frequency to a second pair of said drive inductors located at ends of a second diagonal of said parallelogram, wherein said sensing inductor generates a first output voltage at said first frequency and a second output voltage at said second frequency; and a processor coupled to said sensing inductor for determining a position of said sensing inductor relative to said drive inductors using said first output voltage and said second output voltage.