CAPACITIVE SENSOR AND COMBINED CAPACITIVE DISPLACEMENT MEASUREMENT SENSING SYSTEM

摘要

A capacitive sensor (100) and a combined capacitive displacement measurement sensing system consists of at least one STATORs (104, 105) comprising a first capacitance electrode set (11; or 13) with m electrically connected conductive electrodes (11-1, 11-2,...11-n,...11-m; or 13-1,13-2,...13-n,...13-m) and a second capacitance electrode set (12; or 14) with m electrically connected conductive electrodes (12-1, 12-2,...12-n,...12-m; or 14-1,14-2,...14-n,...14-m). One of corresponding first set and one of corresponding second set (11 and 12, or 13 and 14) of electrodes are arranged alternately at preset distances on electrically insulated substrates (17, 19). In addition, the capacitive sensor (100) consist of at least one MOVER (106) comprising one or more sets of ground electrodes (15-1, 15-2,...15-n; or 16-1,16-2,...16-n). Corresponding capacitive electrodes of the STATORs (104, 105) and the ground electrodes of the MOVER (106) form capacitors. The MOVER (106) moves relatively to the STATORs (104,105) in a controllable manner to change the overlapping areas of the capacitors, resulting changes of the capacitances, thereof, and that reflects displacement measurement. The present invention further consists of signal processing system for capturing and converting electronic signals of the variable capacitors to obtain displacement data. While proper layout of electrodes reduces the impact due to the changes in capacitor gap during moving, mutual offsets of electrodes overcomes dead zones of measurements, together with proper design of electrode shape, thus to achieve both high-precision and long-range absolute displacement measurement.