Microgyroscope for Determining Rotational Movements About Three Spatial Axes which are Perpendicular to One Another

Abstract

A micro gyroscope for determining rotational movements about three spatial axes x, y and z, which are perpendicular to one another has a substrate (I) on which a plurality of masses ( 2, 3 ) oscillating tangentially about the z axis, which is perpendicular to the substrate (I), are arranged. The oscillating masses ( 2, 3 ) are fastened on the substrate (I) by means of springs ( 5, 6, 8 ) and tie bolts ( 7, 9 ). Driving elements (II) serve to maintain oscillating, tangential vibrations of the masses ( 2, 3 ) about the z axis, as a result of which, upon rotation of the substrate (I) about any spatial axis, the masses ( 2, 3 ) are subjected to Corolis forces and deflections caused as a result. Sensor elements detect the deflections of the masses ( 2, 3 ) on the basis of the Corolis forces generated. Some of the masses ( 2, 3 ) oscillating about the z axis are mounted in a tiltable manner substantially about the x axis which runs parallel to the substrate (I). Others of the masses ( 2, 3 ) oscillating about the z axis are mountable in a tiltable manner substantially about the y axis, which likewise runs parallel to the substrate (I). At least one other of the oscillating masses ( 2, 3 ) can be additionally at least partially deflected substantially radially to the z axis in the x-y plane parallel to the plane of the substrate (I). Said additionally radially deflectable z mass ( 3 ) is assigned a sensor element ( 12 ) which can likewise be deflected radially with respect to the z axis but does not oscillate about the z axis.

What is claimed is: 
     
         1 . A gyroscope for detecting movement around a z axis, the gyroscope comprising:
 a substrate;   at least one anchor coupled to the substrate;   a first driving mass coupled to the at least one anchor, the first driving mass radially oscillate with respect to a location on the substrate;   a second driving mass coupled to the at least one anchor, the second driving mass radially oscillate with respect to a location on the substrate;   a first sensor electrode coupled to the first driving mass, the first sensor electrode detects a first capacitive change caused by a rotational movement around the z-axis and generates a first signal; and   a second sensor electrode coupled to the first driving mass, the second sensor electrode detects a second capacitive change caused by the rotational movement around the z-axis and generates a second signal, the first and second signals relate to a differential measurement of the rotational movement around the z-axis.   
     
     
         2 . The gyroscope of  claim 1  wherein the first sensor electrode comprises a first plate electrode located above the first driving mass. 
     
     
         3 . The gyroscope of  claim 2  wherein the first plate electrode moves in response to rotational motion about the z-axis, the first plate electrode movement causes the first capacitive change within the first sensor electrode. 
     
     
         4 . The gyroscope of  claim 3  wherein the first plate electrode and the first sensor electrode are in the same plane. 
     
     
         5 . The gyroscope of  claim 3  wherein the first plate electrode is on a side surface of the first driving mass and the first sensor electrode is located adjacent to and in the same plane as the first driving mass. 
     
     
         6 . The gyroscope of  claim 1  wherein the second sensor electrode comprises first and second plates, the first and second sensor electrodes move relative to each other to detect in-plane capacitive movement between the first and second plates. 
     
     
         7 . The gyroscope of  claim 1  wherein oscillation of the first and second driving masses are synchronized with each other using at least one spring. 
     
     
         8 . The gyroscope of  claim 7  wherein the first and second driving masses oscillate along a first axis and are 180 degrees out of phase from each other. 
     
     
         9 . The gyroscope of  claim 7  wherein the first and second driving masses are separated by the central anchor and that oscillate at 180 degrees out of phase from each other. 
     
     
         10 . A method for detecting rotational rate about a z-axis, the method comprising:
 causing radial oscillation of a first pair of driving masses relative to a location on a substrate, the first pair of driving masses oscillating 180 degrees out of phase with each other and along a first axis;   detecting a first capacitance change within a first sensor electrode associated with a first driving mass within the first pair of driving masses;   detecting a second capacitance change within a second sensor electrode associated with a second driving mass within the second pair of driving masses; and   determining a first rotation rate about the z-axis based at least in part on the first and second capacitance changes.   
     
     
         11 . The method of  claim 10  wherein the first pair of driving masses are coupled using a plurality of springs. 
     
     
         12 . The method of  claim 10  wherein the first pair of driving masses are coupled using a first joint at the location on the substrate, the first joint allowing the first pair of driving masses to deflect and sense differential measurements related to the first rotational rate. 
     
     
         13 . The method of  claim 10  wherein the oscillation of the first pair of driving masses is at least partially controlled by a plurality of springs. 
     
     
         14 . The method of  claim 13  wherein the plurality of springs provides synchronized oscillation of the first pair of driving masses. 
     
     
         15 . The method of  claim 10  wherein at least two driving electrodes drive the radial oscillation of the first pair of driving masses. 
     
     
         16 . A gyroscope comprising:
 a substrate;   an anchor coupled to the substrate;   a first drive mass coupled to the anchor, the first drive mass radially oscillates along a first axis;   a second drive mass coupled to the anchor, the second drive mass radially oscillates along the first axis and is synchronized with the first drive mass; and   a first synchronization spring coupling the first and second drive masses, the synchronized radial oscillation of the first and second drive masses being at least partially controlled by the first synchronization spring.   
     
     
         17 . The gyroscope of  claim 16  further comprising:
 a first sensor coupled to the first drive mass, the first sensor detects movement around a z-axis; 
 a second sensor coupled to the second mass, the second sensor detects movement around the z-axis; and 
 wherein the first and second sensors generate signals from which a first differential measurement is derived. 
 
     
     
         18 . The gyroscope of  claim 17  further comprising:
 a first sensor electrode associated with the first sensor, the first sensor electrode detects a first capacitive change caused by a first movement around the z-axis; and 
 a second sensor electrode associated with the second sensor, the second sensor electrode detects a second capacitive change caused by the first movement around the z-axis. 
 
     
     
         19 . The gyroscope of  claim 18  wherein the first sensor electrode comprises a first plate electrode and a second plate electrode that move tangentially to each other. 
     
     
         20 . The gyroscope of  claim 16  further comprising:
 a first drive element coupled to the first drive mass, the first drive element causing the first drive mass to radially oscillate along the first axis; and 
 a second drive element couple to the second drive mass, the second drive element causing the second drive mass to radially oscillate.