Opto-mechanical tilt and inertial force sensor

• US 20070261504A1
• Filed: 05/11/2006
• Published: 11/15/2007
• Est. Priority Date: 05/11/2006
• Status: Active Grant

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: Murelitharan, Munlandy
• Granted Patent: US 7,726,213 B2
• Time in Patent Office: Days
• US Class Current: 73/865.900
• CPC Class Codes: G01C 9/12 by using a single pendulum plumb lines G01C15/10
• CPC Class Codes: G01P 15/093 by photoelectric pick-up

Abstract

A sensor having a mass that moves relative to a structure is disclosed. The mass is attached to the structure by a rigid member such that the mass moves around a pivot point on the structure, the pivot point remaining fixed with respect to the structure as the mass moves. A code scale is attached to the mass. An imaging system that is fixed with respect to the structure forms an image of the code scale. A controller provides an indication of a position of the mass relative to the structure using the code scale image. The rigid member can include a surface having the code scale thereon, the surface rotating about the pivot point as the mass moves such that the surface remains at a fixed distance from the pivot point as the mass moves.

Claims

1. A sensor comprising:

a structure;

a mass that moves relative to said structure, said mass is attached to said structure by a rigid member such that said mass moves around a pivot point on said structure, said pivot point remaining fixed with respect to said structure as said mass moves;

a code scale attached to said mass;

an imaging system for forming an image of said code scale, said imaging system being fixed with respect to said structure;

a controller that provides an indication of a position of said mass relative to said structure, said controller utilizing said code scale image.

2. The sensor of claim 1 wherein said indication comprises a determination of an inclination of said structure with respect to the earth.

3. The sensor of claim 1 wherein said imaging system comprises a light source for illuminating said code scale and an imaging array.

4. The sensor of claim 1 wherein said rigid member comprises a surface having said code scale thereon, said surface rotating about said pivot point as said mass moves such that said surface remains at a fixed distance from said pivot point as said mass moves.

5. The sensor of claim 1 wherein said mass is located in a chamber attached to said structure, said chamber comprising a liquid through which said mass moves.

6. The sensor of claim 5 wherein said chamber comprises a transparent window and wherein said imaging system is located outside said chamber, said imaging system forming said image through said transparent window.

7. The sensor of claim 5 wherein said liquid is transparent to light.

8. The sensor of claim 1 further comprising a spring mechanism that applies a restoring force to said mass when said mass moves from an equilibrium position with respect to said structure.

9. The sensor of claim 8 wherein said restoring force is a monotonic function of a distance between said mass and said equilibrium position.