Tests of a novel 3 DOF differential capacitive sensor

A four-quadrants differential set-up made by two plane-parallel capacitors to measure displacements and small angle rotations is presented. The capacitors electrodes are interfaced to a bridge-based circuit of new conception to be used either for displacements and small angle readings, independently and almost simultaneously detected. Sensitivities of about 0,11 V/μm with a 0,1% relative standard deviation, and of 0,13 V/mrad with a 0,3% relative standard deviation, were determined over displacements up to ±50 μm and yaw rotations up to ±10 μrad.