Patent ID: 7640803
Filing Date: 2010-01-05
Classification: G01C,G01P

Abstract:
1. An inertial sensor, comprising: a planar, H-shaped mass suspended by a pair of elongated springs disposed on opposite sides thereof so as to define a spring-mass system; means for exciting the sensor in a first torsional resonance mode and at a constant amplitude of motion; and, means for monitoring the rotational motion of the inertial sensor in a second torsional mode and for measuring the rate of rotation of the sensor therein, wherein: the springs have substantially identical rectangular cross-sections, sides perpendicular to the plane of the mass and upper and lower surfaces parallel to the plane of the mass, the springs being coplanar with the mass and coaxial with a rotation sensing axis of the sensor passing through the center of mass of the mass, the spring-mass system has a first torsional resonance about a drive axis of the sensor disposed perpendicular to the plane of the mass and extending through the center of mass thereof that is a function of the cross-sectional width of the springs, and a second torsional resonance about a third axis of the sensor passing through the center of mass of the mass and disposed perpendicular to the rotation sensing and drive axes of the sensor that is a function of the cross-sectional height of the springs, the respective frequencies of the first and second torsional resonances are substantially equal to each other, the monitoring and measuring means uses the motion of the inertial sensor in the first torsional mode to determine the average position of the mass and thereby measure acceleration of the sensor, and, the sensor is operable to measure the rate of rotation of the sensor about the rotation sensing axis and a linear acceleration of the sensor along at least one of the drive and the third axes.