A capacitive system for micro/nano positioning and attitude controls

A novel multi-electrodes plane capacitive sensor was designed and built at INRIM. The circular active electrode of a plane-parallel capacitive sensor was built in four sectors of equal area. Each sector is guarded by a circular guard ring and by other sectors. The output signals of the four independent sensors-channels of the measuring electronics are summed to measure the displacement and differentiated. From the relative differences of sectors signals, rotations of the moving elements are obtained. The electronics was optimized for a full scale displacement range of some hundreds of micrometers