Xj. Li et Gcm. Meijer, A NEW METHOD FOR THE MEASUREMENT OF LOW-SPEED USING A MULTIPLE-ELECTRODE CAPACITIVE SENSOR, IEEE transactions on instrumentation and measurement, 46(2), 1997, pp. 636-639
A novel method for the measurement of low speeds by using a few-cost c
apacitive sensor is presented, Its main advantages are its simplicity,
low cost and the very low speed (as low as 0.02 rad/s), which can be
measured with a relatively high resolution in a short measurement time
, The multiple capacitors, whose values are piece-wise linearly relate
d to the position in a periodic way, are used as the sensing elements
of the low-speed sensor, A capacitance-controlled oscillator is used i
n the processing circuit to convert the capacitance to a period modula
ted signal which can be read directly out by a microcontroller, An alg
orithm, which is used to calculate the speed from the measured periods
, either eliminates or strongly reduces the influence of most errors,
The measurement time is relatively short for low speeds, Meanwhile, th
e direction of movement can be indicated.