Position estimation for a capacitively-sensed magnetoelastic rotary microstage using an extended Kalman smoother

An estimation scheme is described for measuring angular rotation of a magnetoelastic rotary micro-stage with capacitive sensing electrodes. Experimental measurements of micro-stage motion are used to create a simulation model for translational dynamics of the stage rotor. A capacitive sensing electrode geometry providing stable peak capacitance measurements at specific rotation angles is then introduced. Application of an extended Kalman smoother to the measurement of rotation angle in the simulated system is shown to produce high precision estimates of angular position near peak capacitance locations.