| 摘要 |
<p>A sensor ( 46 ) for sensing the angular position of a rotatable body ( 10 ) including a stationary transmitter plate ( 12 ) with at least one transmitter electrode ( E, F ), a stationary receiver plate ( 14 ) with at least a first and a second receiver electrode ( A, B, C, D ), and a rotor ( 16 ) formed of a dielectric material and positioned between the facing electrodes ( A , B, C, D, E, F ) of the plates ( 12, 14 ). The rotor ( 16 ) is smaller than the plates ( 12, 14 ) and rotates with the rotatable body ( 10 ) to change the capacitance between the transmitter electrode(s) ( E, F ) and opposed receiver electrodes ( A, B, C, D ). The induced voltages on the receiver electrodes ( A, B, C, D ) indicate the angular position of the rotatable body ( 10 ). Preferably, the sensor ( 46 ) uses a square waveform signal and two transmitter electrodes ( E, F ) receive signals 180 degrees out of phase. Then, four receiver electrodes ( A, B, C, D ) forming two receiver pairs ( AC, BD ) are connected so that the current flowing between each pair is measured and converted to a voltage. A lookup table compares the values of the voltage pairs to known values ( 46, 48 ) from calibration, giving the angular position.</p> |
