MICROMACHINED CROSS-DIFFERENTIAL DUAL-AXIS ACCELEROMETER

Micromachined accelerometer having one or more proof masses (16, 36, 37, 71, 72) mounted on one or more decoupling frames (17, 38, 39) or on a shuttle (73) such that the proof mass(es) can move along a first (y) axis in response to acceleration along the first axis while being constrained against movement along a second (x) axis and for torsional movement about a third (z) axis perpendicular to the first and second axes in response to acceleration along the second axis. Electrodes (26, 53, 54, 78, 79) that move with the proof mass(es) are interleaved with stationary electrodes (27, 56, 57, 81, 82) to form capacitors (A - D) that change in capacitance both in response to movement of the proof mass(es) along the first axis and in response to torsional movement of the proof mass(es) about the third axis, and circuitry (31 - 34) connected to the electrodes for providing output signals corresponding to acceleration along the first and second axes. The capacitances of two capacitors on each side of the second axis change in the same direction in response to acceleration along the first axis and in opposite directions in response to acceleration along the second axis. Signals from the capacitors that change capacitance in opposite directions both in response to acceleration along the first axis and in response to acceleration along the second axis are differentially combined to provide first and second difference signals, and the difference signals are additively and differentially combined to provide output signals corresponding to acceleration along the first and second axes. L'invention concerne un accéléromètre micro-usiné comportant une ou plusieurs masses étalons (16, 36, 37, 71, 72) montées sur un ou plusieurs cadres de couplage (17, 38, 39) ou sur une navette (73) de telle sorte que la ou les masses étalons puissent se déplacer le long d'un premier axe (y) en réponse à une accélération le long du premier axe tout en étant contraint vis-à-vis d'un mouvement le long d'un second axe (x) et pour un mouvement de torsion autour d'un troisième axe (z) perpendiculaire au premier et second axe en réponse à une accélération le long du second axe. Des électrodes (26, 53, 54, 78, 79) qui se déplacent avec la ou les masses étalons sont entrelacées avec des électrodes stationnaires (27, 56, 57, 81, 82) pour former des condensateurs (A à D) qui changent de capacité à la fois en réponse à un mouvement de la ou des masses étalons le long du premier axe et en réponse à un