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James Crumley, Applied Physics


Measuring where an object is located is an invaluable tool across many disciplines. An emerging technology utilizes the magnetic field readings of a known source to locate where the object is in space. This type of sensor is useful since the target object can be measuring without contact, such as measuring the position of a piston through a cylinder wall. However, many problems arise since magnetic fields combine and distort when multiple fields are present. The magnetic disturbance has not been characterized for magnetic sensors in close proximity to DC electric motors. By modeling the known magnetic field source and gathering data of the distorted signal, a model of the DC motor field can be developed and later filtered out of the raw signal. In this thesis, a model for the magnetic field of a dipole magnet combined with that of a DC motor is explored in order to filter out the magnetic disturbances and regain the dipole field necessary for accurate position measurements. A characteristic DC magnetic field offset along with oscillations of the measured field has been shown to be attributed to the DC electric motor’s influence and has been modeled.