Xj. Li et al., AN ACCURATE LOW-COST CAPACITIVE ABSOLUTE ANGULAR-POSITION SENSOR WITHA FULL-CIRCLE RANGE, IEEE transactions on instrumentation and measurement, 45(2), 1996, pp. 516-520
A novel high-performance smart capacitive angular-position sensor with
a full-circle measurement range is presented, The sensor is mainly co
mposed of three parts: the capacitive sensing element, a signal proces
sor and a microcontroller, Using an appropriate algorithm, the effects
of the main undesired influences are eliminated or strongly reduced,
The measurement range covers the full-circle range (360 degrees). The
structure of the sensing element is optimized to reduce the influence
of the electric-field-bending effect and the mechanical errors, The si
gnal processor has a multicapacitance input and a single period-modula
ted output, and includes a nearly linear capacitance/period converter.
The microcontroller acquires output data from the processor, calculat
es the positions and optionally communicates with the outside digital
world. The resolution of the smart capacitive angular-position sensor
is 1.5 arcsec, and the nonlinearity is less than +/- 58 arcsec over th
e 0-360 degrees range for a measurement time of 140 ms.