Centripetal opposed pendulous accelerometer

Abstract

The invention utilizes a sensing body having a non-zero product of inertia to sense acceleration when spun about the y'-axis of an x'-y'-z' Cartesian coordinate system. The product of inertia is computed with respect to an x-y-z coordinate system fixed in the sensing body, the z-axis being in the x'- z' plane, they and y' axes being aligned in the absence of acceleration. The sensing body is pivotally attached to a platform and pivots about an axis parallel to the z-axis. A torquing device applies a torque about the z-axis to the sensing body sufficient to cause the angle between the y-axis and the y'-axis to be zero in the absence of acceleration when the sensing body is being spun at predetermined rate. The accelerometer also includes an orientation sensor which provides a measure of the angle between the y-axis and the y'-axis. A drive assembly rotates the platform about the y'-axis. A control circuit receives the output of the orientation sensor and causes the drive assembly to drive the platform at a rate which causes the orientation angle to be near zero. A rotation sensor provides a measure of either the angle of rotation of the platform or the angular velocity of the platform. The acceleration is determinable from the angular velocity of the platform and the velocity is determinable from the angle of rotation. The invention can also use an assembly of N individually-pivoting sensing bodies to sense acceleration.