SENSOR WITH ELECTROSTATIC PENDULAR ACCELEROMETER AND METHOD OF CONTROLLING SUCH A SENSOR

摘要

An accelerometer sensor and method of controlling the sensor, the accelerometer sensor including at least one electrostatic pendular accelerometer having stationary first and second electrodes fastened to a housing and connected to an exciter circuit, and a third electrode carried by a pendulum connected to the housing, thereby being movable and being connected to a detector circuit. The exciter circuit has an output connected to a switch connected to the first and second electrodes, the switch having a first connection position and a second connection position for selectively connecting the first or second electrode to the exciter circuit. The detector circuit, the exciter circuit, the switch, and the detector circuit are connected to a control circuit arranged so the first and second electrodes are excited by pulse trains, thus keeping the pendulum in a setpoint position and determining an acceleration to which the pendulum is subjected.

主权项

1. A method of controlling a sensor comprising at least one electrostatic pendular accelerometer having stationary first and second electrodes that are secured to a housing and that are connected to an exciter circuit, and a third electrode that is carried by a pendulum connected to the housing so as to be movable and that is connected to a detector circuit, the method comprising the steps of:
during two successive detection stages, exciting in alternation first one and then the other of the stationary electrodes by detection pulses in order to detect a first capacitance and a second capacitance between the movable electrode and the respective stationary electrodes; estimating a position of the pendulum from the detected capacitances; determining a servo-control error corresponding to a difference between the estimated position and a setpoint position; on the basis of the servo-control error, determining a command specifying whether the next detection pulse is to push or to pull the pendulum; calculating the acceleration that is to be measured as a function of the setpoint position and of the determined command; and during a control stage, exciting one or the other of the stationary electrodes by control pulses for servo-controlling the servo-controlled error to zero.