EXTENDED STROKE POSITION SENSOR

摘要

A position sensing system including a waveguide positioned adjacent to a quantity of soft or semi-soft magnetic material is described. A magnet, movable relative to the waveguide and magnetic material, closely positioned to the magnetic material and configured to generate a local magnetic field sufficient to locally saturate the magnetic material. The saturated magnetic material operates to change the characteristic impedance of the waveguide at the point of saturation, which causes signals to be reflected at the point of impedance discontinuity. A signal generator for communicating a first signal to the waveguide and a signal receiver for receiving the first signal and/or the reflected signal and a position sensing processor or circuit for determining the position of the waveguide relative to the magnet based on the first signal and the reflected signal are described.

主权项

1. A position sensing system comprising:
an extended stroke position sensor comprising: a waveguide having a given characteristic impedance; and a magnetic material positioned in close proximity to the waveguide, the magnetic material comprising soft or semi-soft magnetic material; a signal generator communicatively coupled to the waveguide and a signal receiver, the signal generator configured to generate a first signal and communicate the first signal to the waveguide and the signal receiver; one or more impedance matching devices electrically coupled to the waveguide and configured such that the waveguide is impedance matched with the signal generator and the signal receiver; a magnet movable relative to the extended stroke position sensor, the magnet configured to generate a magnetic field sufficient to locally saturate the magnetic material, wherein the magnetic material configures to cause an impedance discontinuity in the waveguide such that the first signal is reflected at the point of the impedance discontinuity and communicated to the signal receiver; and a position sensor circuit communicatively coupled to the signal receiver, the position sensor circuit configured to determine the position of the magnet relative to the extended stroke position sensor based in part on the first signal and the reflected signal as received by the signal receiver.