CONSTANT CHARGE CONTROL CIRCUIT FOR A CAPACITIVE MOTOR, IN PARTICULAR FOR A RATE GYRO OR AN ACCELEROMETER

摘要

An electrostatic motor is constituted by a capacitor (10) having relatively movable electrodes (11, 12) separated by a variable gap (13). The control circuit includes a DC source (60) which is servo-controlled to current measurement means (20) and integrator means (30) for calculating the charge on the capacitor plates and for maintaining said charge constant (Q0). By applying servo control to keep the charge constant, the force on the plates is independent of the variable value of the gap (14). The charge is preferably on/off switched with a pulse width modulation ratio that is a function of the force which is to be applied.