A novel angular joint-sensor using a fluxgate magnetometer

We present a new angular joint-sensor by using a microfabricated fluxgate magnetometer. Fluxgates are normally used for geodetic measurements, navigation of satellites or as an electronic compass. For use as an angular joint-sensor the rotation of a permanent magnet, which transmits the rotation of the joint axis, can be detected by the fluxgate. The measuring range is 180deg. The basic configuration of the fluxgate consists of a helical excitation coil with a soft magnetic toroidal core and a sensing coil wound around the whole body of the core. The integration of the sensor into the joint requires application of miniaturization techniques. The fluxgate is fabricated either monolithically or by mounting the soft magnetic core, for which a new mounting method without gluing is presented. For the optimization of the measured magnetic field self fabricated polymer magnets are used. The sensor works contactless and the output signal is proportional to the angle position of the joint