Inertial Measurement Unit

• US 20110192227A1
• Filed: 02/08/2011
• Published: 08/11/2011
• Est. Priority Date: 02/08/2010
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Post, Ernest, Gershenfeld, Neil
• Granted Patent: US 8,590,377 B2
• Time in Patent Office: Days
• US Class Current: 73/514.01
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01P 15/097 by vibratory elements
• CPC Class Codes: G01P 2015/0805 being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration

Abstract

In exemplary embodiments of this invention, an inertial measurement unit (IMU) includes a cantilevered proof mass and electrostatic drive. The electrostatic drive puts the proof mass into a controlled trajectory in which it oscillates rapidly, for example, by vibrating back and forth in a plane or traveling in a circular or elliptical orbit. The IMU detects lateral or angular acceleration of the IMU, by measuring the perturbations of the proof mass trajectory from the expected motion in a fixed, non-rotating inertial frame. In exemplary embodiments of this invention, the proof mass position and motion are measured by methods of differential potential measurement (with constant slope voltage), differential displacement current measurement, or phase-sensitive or synchronous detection of motion.

Claims

1. A inertial measurement unit, comprising a cantilevered proof mass, an electrostatic drive for putting the proof mass into a controlled trajectory, and a capacitive sensor for measuring the position and motion of the proof mass, wherein lateral acceleration and rotation of the inertial measurement unit may be determined by measuring perturbations in said trajectory from a trajectory that the proof mass would travel in a fixed, non-rotating inertial frame.