Angular direction sensor

• US 3,913,405 A
• Filed: 08/16/1974
• Issued: 10/21/1975
• Est. Priority Date: 08/16/1974
• Status: Expired due to Term

• Current Assignee: Kearfott Guidance and Navigation Corporation
• Original Assignee: Bo H.G. Ljung, John C. Stiles
• Inventors: Stiles, John C., Ljung, Bo H. G.
• Primary Examiner(s): Gill, James J.
• Application Number:
  US05/498,035
• Time in Patent Office: 431 Days
• Field of Search: 73/505,517AV 310/25
• US Class Current: 73/504.14
• CPC Class Codes: G01C 19/5642 using vibrating bars or beams

Abstract

A angular direction sensor formed of a casing and an elongated vibrating element. The vibrating elastic element, such as a rod, is secured at each end to the casing by a flexible connection and is furthermore rigidly connected to vibrating members, providing linear inertial momentum. The linear inertial momentum is obtained by symmetrically arranged members secured to the vibrating element so that the nodal points of the vibrating element are exterior to the same and coincident with the flexible connections to the case.

Claims

1. An angular direction sensor comprising a housing, an elastic a rod located to oscillate within said housing, said rod being supported at each end by a flexible connection within said housing comprising a pair of spaced necked down portions formed in said rod inwardly of the ends, a pair of spaced weight elements concentrically secured to said rod providing an inertial moment estabalishing the nodal points of oscillation exterior of said rod, means for exciting said rod to oscillate in a predefined plane, and pick-off means for providing a signal which varies as a function of the angular relationship of the plane of vibration with respect to the housing.

2. The sensor according to claim 1, wherein said nodal points and said flexible connections coincide.

3. The sensor according to claim 1, wherein said weight elements are symmetrically secured to said member to establish said inertial moment.

4. The indicator according to claim 3, wherein said inertial elements are adjustable with respect to said member to enable adjustments of said nodal points.

5. The sensor according to claim 1, wherein said pick-off and exciting means comprises a plurality of sensing electrodes spaced uniformaly about said rod and a plurality of driving electrodes spaced uniformly about said rod, and means foR exciting said rod to oscillate in any plane, unrestricted by the location of said electrodes.

6. The sensor according to claim 5, wherein said electrodes comprise at least two sets of orthogonally arranged paired electrodes.

7. The angular direction sensor according to claim 6, including means for controlling the drive current as a function of the pick-off signal to maintain said rod oscillating at a constant amplitude.

8. The angular direction sensor according to claim 6, including a cylindrical conductive ring secured to said rod between said weight elements, said electrodes comprising arcuate plates fixed in said housing and surrounding said ring.

9. The angular direction sensor according to claim 5 comprises two pairs of electrodes, each pair being arranged perpendicularly to each other, and connected to a voltage bias source by means of resistors.