Accelerometer including rectangular coil and rectangular pole piece

Patent metadata

Field	Value
Publication number	US-11275098-B2
Application number	US-202016928725-A
Country	US
Kind code	B2
Filing date	Jul 14, 2020
Priority date	Jul 14, 2020
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

This disclosure is related to devices, systems, and techniques for determining an acceleration. For example, an accelerometer system includes a proof mass, a pole piece connected to the proof mass, and a coil disposed around the pole piece and connected to the proof mass, where the coil is rectangular in shape. Additionally, the accelerometer system includes circuitry configured to deliver an electrical signal to the coil in order to maintain the proof mass at a null position and determine an electrical current value corresponding to the electrical signal. Additionally, the circuit is configured to identify, based on the electrical current value, an acceleration of the accelerometer system.

First claim

What is claimed is:

1. An accelerometer system comprising:
a proof mass;
a pole piece that extends along a longitudinal axis, wherein the pole piece is connected to the proof mass, wherein a cross section of the pole piece is rectangular in shape, wherein the cross section of the pole piece represents a cross section that is perpendicular to the longitudinal axis of the pole piece, and wherein the pole piece comprises a first pole piece outer side, a second pole piece outer side, a third pole piece outer side opposite the first pole piece outer side, and a fourth pole piece outer side opposite the second pole piece outer side;
a coil having a cross section that is rectangular in shape, wherein the cross section of the coil is perpendicular to the longitudinal axis of the pole piece,
wherein the coil comprises a first coil inner side, a second coil inner side, a third coil inner side opposite the first coil inner side, and a fourth coil inner side opposite the second coil inner side,
wherein the coil is disposed around the pole piece so that a first space exists between the first pole piece outer side and the first coil inner side, a second space exists between the second pole piece outer side and the second coil inner side, a third space exists between the third pole piece outer side and the third coil inner side, and a fourth space exists between the fourth pole piece outer side and the fourth coil inner side, wherein the coil is connected to the proof mass; and
circuitry configured to:
deliver an electrical signal to the coil in order to maintain the proof mass at a null position;
determine an electrical current value corresponding to the electrical signal; and
identify, based on the electrical current value, an acceleration of the accelerometer system.

2. The accelerometer system of claim 1 , wherein the accelerometer system further comprises:
a non-moving member,
wherein the circuitry is configured to:
receive, from a capacitance sensor, a capacitance signal indicating a capacitance value, wherein the capacitance value is correlated with a width of a gap between the proof mass and the non-moving member; and
generate the electrical signal to include an electrical current value which maintains the proof mass at the null position by maintaining the width of the gap between the proof mass and the non-moving member at a null gap width.

3. The accelerometer system of claim 2 , wherein the pole piece is a first pole piece, wherein the coil is a first coil, wherein the electrical signal is a first electrical signal, wherein the electrical current value is a first electrical current value, and wherein the accelerometer system further comprises:
a second pole piece, wherein the second pole piece is connected to the proof mass; and
a second coil disposed around the second pole piece, wherein the second coil is connected to the proof mass, and wherein the second coil is rectangular in shape,
wherein the circuitry is further configured to:
deliver a second electrical signal to the second coil in order to maintain the proof mass at the null position;
determine a second electrical current value corresponding to the second electrical signal; and
identify, based on the second electrical current value and the first electrical current value, the acceleration of the accelerometer system.

4. The accelerometer system of claim 3 , wherein the non-moving member is a first non-moving member, wherein the capacitance sensor is a first capacitance sensor, wherein the capacitance signal is a first capacitance signal, wherein the capacitance value is a first capacitance value, wherein the null gap width is a first null gap width, and wherein the acceleration system further comprises:
a second non-moving member,
wherein the circuitry is configured to:
receive, from a second capacitance sensor, a second capacitance signal indicating a second capacitance value, wherein the second capacitance value is correlated with a width of a gap between the proof mass and the second non-moving member; and
generate the second electrical signal to include a second electrical current value which maintains the proof mass at the null position by maintaining the width of the gap between the proof mass and the second non-moving member at a second null gap width.

5. The accelerometer system of claim 1 , wherein the circuitry is configured to maintain the proof mass at the null position such that the longitudinal axis of the pole piece remains perpendicular to a plane of the proof mass.

6. The accelerometer system of claim 5 , wherein the acceleration of the accelerometer system identified by the circuitry represents an acceleration perpendicular to the plane of the proof mass.

7. The accelerometer system of claim 1 , wherein the circuitry is configured to identify the acceleration by calculating the acceleration based on a relationship between the electrical current value and the acceleration, wherein the electrical current value is positively correlated with the acceleration.

8. The accelerometer system of claim 1 ,
wherein a magnetic field at the first coil inner side is constant along a length of the first coil inner side from a first end of the first coil inner side to a second end of the first coil inner side,
wherein a magnetic field at the second coil inner side is constant along a length of the second coil inner side from a first end of the second coil inner side to a second end of the second coil inner side,
wherein a magnetic field at the third coil inner side is constant along a length of the third coil inner side from a first end of the third coil inner side to a second end of the third coil inner side, and
wherein a magnetic field at the fourth coil inner side is constant along a length of the fourth coil inner side from a first end of the fourth coil inner side to a second end of the fourth coil inner side.

9. The accelerometer system of claim 1 ,
wherein the coil is configured to receive a magnetic flux from the pole piece, wherein the magnetic flux passes through the coil to a non-moving member, and
wherein by delivering the electrical signal to the coil, the circuitry is configured to induce a flow of the electrical current around a path of the coil, causing a force to maintain the proof mass at the null position.

10. The accelerometer system of claim 9 , wherein a magnitude of the force represents a cross-product of a magnitude of the electrical current which flows around the path of the coil and a magnitude of the magnetic flux which passes through the coil.

11. A method comprising:
delivering, by circuitry of an accelerometer system, an electrical signal to a coil in order to maintain a proof mass at a null position, wherein the accelerometer system comprises:
the proof mass;
a pole piece that extends along a longitudinal axis, wherein the pole piece is connected to the proof mass, wherein a cross section of the pole piece is rectangular in shape, wherein the cross section of the pole piece represents a cross section that is perpendicular to the longitudinal axis of the pole piece, and wherein the pole piece comprises a first pole piece outer side, a second pole piece outer side, a third pole piece outer side opposite the first pole piece outer side, and a fourth pole piece outer side opposite the second pole piece outer side;
the coil having a cross section that is rectangular in shape, wherein the cross section of the coil is perpendicular to the longitudinal axis of the pole piece, wherein the coil comprises a first coil inner side, a second coil inner side, a third coil inner side opposite the first coil inner side, and a fourth coil inner side opposite the second coil inner side,

Assignees

• Honeywell Int Inc

Inventors

• Dwyer Paul W

Classifications

• G01P15/13

  by measuring the force required to restore a proofmass subjected to inertial forces to a null position · CPC title

• G01P15/125 Primary

  by capacitive pick-up · CPC title

• G01P15/132 Primary

  with electromagnetic counterbalancing means · CPC title

• G01P2015/0837

  the mass being suspended so as to only allow movement perpendicular to the plane of the substrate, i.e. z-axis sensor · CPC title