Sensor with moving sensitive element having mixed vibrating and pendular operation, and methods for controlling such a sensor

• US 9,519,004 B2
• Filed: 10/21/2014
• Issued: 12/13/2016
• Est. Priority Date: 11/20/2013
• Status: Active Grant

• Current Assignee: Safran Electronics & Defense
• Original Assignee: Sagem Defense Securite SA (Safran SA)
• Inventors: Jeanroy, Alain
• Primary Examiner(s): Caputo, Lisa
• Assistant Examiner(s): DUNLAP, JONATHAN M
• Application Number:
  US15/037,518
• Publication Number:
  US 20160282382A1
• Time in Patent Office: 784 Days
• Field of Search: 735/041.2, 735/041.4, 735/040.4, 738/620.41, 735/10, 735/143.2, 735/142.9, 735/143.8
• US Class Current: 1/1
• 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: G01C 19/5642 using vibrating bars or beams
• CPC Class Codes: G01C 19/5656 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01C 19/5733 Structural details or topology
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/0888 for indicating angular acceleration
• CPC Class Codes: G01P 15/097 by vibratory elements
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/14 by making use of gyroscopes gyroscopes per se G01C19/00
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type
• CPC Class Codes: G01P 2015/082 for two degrees of freedom of movement of a single mass
• CPC Class Codes: G01P 2015/0848 using a plurality of mechanically coupled spring-mass systems, the sensitive direction of each system being different
• CPC Class Codes: G01P 2015/0857 using a particular shape of the suspension spring

Abstract

A sensor comprising: a stand; a first body movable along a sensing axis; two pairs of second bodies arranged symmetrically relative to the first body and along the sensing axis; transducers for detecting a position of the first body relative to the stand, for setting the second bodies into vibration along a vibration axis, and for detecting respective vibration frequencies of the second bodies; and surface electrostatic coupling means connecting each second body to the first body in such a manner that a movement of the first body relative to the stand along the sensing axis gives rise respectively to an increase and to a decrease in the electrostatic coupling for one and the other of the pairs of second bodies. Methods of controlling such a sensor.

Claims

1. A sensor comprising:

a stand;

a first body connected to the stand to be movable along a sensing axis by first suspension means defining a suspension plane;

two resonators that are arranged symmetrically about the first body along the sensing axis and each of which comprises a pair of second bodies each connected to the stand by second suspension means in order to be capable of vibrating along a vibration axis that is substantially perpendicular to the sensing axis, and that are connected to each other by third suspension means;

transducer members connected to a control unit for detecting a position of the first body relative to the stand, for setting the second bodies into vibration along the vibration axis, and for detecting respective vibration frequencies of the second bodies; and

surface electrostatic coupling means connecting each second body to the first body in such a manner that a movement of the first body relative to the stand along the sensing axis leads to an increase in electrostatic coupling for one of the pairs of second bodies and to a decrease in electrostatic coupling for the other pair of second bodies.

2. The sensor according to claim 1, wherein the resonators are arranged on either side of a portion of the first body, the surface electrostatic coupling means being mounted between said portion and the second bodies.

3. The sensor according to claim 2, wherein the first body has two cavities that are in alignment with each other on the sensing axis and each of which receives one of the pairs of second bodies.

4. The sensor according to claim 1, wherein the third suspension means comprise at least one elastically deformable strip given a lozenge shape having a first diagonal that is parallel to the vibration axis and that is defined by first vertices connected to the bodies and a second diagonal that is parallel to the sensing axis and that is defined by second vertices connected to the stand by links in such a manner that the second vertices are movable solely along the sensing axis.

5. The sensor according to claim 1, wherein the transducer members are also arranged to move the first body.

6. The method of controlling a sensor according to claim 5, comprising the step of causing the first body to perform a predetermined movement, and the step of processing a signal coming from the transducer members of the resonators in order to determine a measurement value.

7. A method of controlling a sensor according to claim 1, the method including the step of detecting a movement of the first body in order to determine a first measurement value, and the step of detecting a variation in the frequencies of the resonators in order to determine a second measurement value.

8. The method according to claim 7, comprising the step of retaining as the final measurement value a mean of the first measurement value and of the second measurement value.