Simulation and Robustness Analysis for a Novel Capacitive/Magnetic Full-Turn Absolute Angular Position Sensor

In order to reduce the influence of axial displacement and/or to ease the assembly, certain capacitive angular sensors use symmetric designs limiting their absolute measuring range to (360/spl deg//n) where n is the number of blades. This paper presents a combined sensor that utilizes a Wiegand sensor to obtain additional information needed to resolve 360/spl deg/. Since magnetic and electric fields required by the sensing principles do not interfere, one single rotor design can be used for both fields. When the receiver coil on a Wiegand sensor has to drive a current, this current influences the shape and duration of the pulse generated by the sensor. We found that shape and amplitude of the pulse vary depending on the strength of the applied fields and the location of the initial inverse nucleation. Since most of design optimization for capacitive sensors is done by means of simulations, an adequate model of the combined sensor is needed. For the capacitive part, numerical approaches such as the finite element method are available. For the pulse wire part, an extended Ising model has been developed; results of measurements and numerical simulations are reported.