AN EFFICIENT RETRIEVING ALGORITHM FOR ACCURATE CAPACITIVE POSITION SENSORS

In capacitive position sensors many problems of mechanical origin can be solved by using well-designed multi-capacitance sensing elements. T his paper discusses a new and efficient algorithm to retrieve the meas urand from data measured using multi-capacitance capacitive elements. An overview is presented of the entire capacitive position-sensor syst em and shows that the design aspects of the various system parts and t he retrieving algorithm are closely related to each other. After formu lating four basic requirements, the complete set of retrieving algorit hms satisfying these four basic requirements is derived in a mathemati cal way. From this complete set, an optimum algorithm is selected, wit h respect to the smallest non-linearity possible, by applying the tech nique of fine tuning. Numerical simulations and experiments show that this algorithm is very effective in obtaining a high accuracy and a lo w cross-sensitivity.