Investigation of the effects of design parameters on output characteristics of capacitive angular displacement sensors by finite element field modelling

The effects of design parameters on performance characteristics of a capacitive angular displacement sensor used in limited angle torque motors are investigated. This is done by 2D finite element modelling and computation of electrostatic fields in the complex geometry of the sensor. Results are presented in terms of sensor's output characteristic showing the effects of some of its material and geometric parameters. The output characteristic investigated is the variation of sensor output voltage V with angular position /spl theta/ of the motor rotor, V=f(/spl theta/). The design parameters used comprise permittivities of various dielectric materials and angular width w/sub 1/ of the sensor.