CN109164273B

CN109164273B - Permanent magnetic torquer for accelerometer

Info

Publication number: CN109164273B
Application number: CN201810818839.4A
Authority: CN
Inventors: 梁璞; 张习文; 赵坤帅; 李鹏飞; 张志刚; 王晓勇; 孙继奕
Original assignee: Xian Flight Automatic Control Research Institute of AVIC
Current assignee: Xian Flight Automatic Control Research Institute of AVIC
Priority date: 2018-07-24
Filing date: 2018-07-24
Publication date: 2021-04-20
Anticipated expiration: 2038-07-24
Also published as: CN109164273A

Abstract

The invention belongs to the technical field of flexible pendulum accelerometers, and particularly relates to a silicon-based coil-based permanent magnet torquer for an inertial navigation accelerometer. The permanent magnetic torquer for the accelerometer comprises a yoke iron, a permanent magnet, a magnetic conductive sheet and a silicon-based coil, wherein the yoke iron is positioned at the bottommost part, the permanent magnet is fixed on the yoke iron, and the magnetic conductive sheet is fixed on the upper surface of the permanent magnet. A permanent magnet air gap is formed between the yoke iron and the magnetic conductive sheet, the silicon-based coil is positioned in the permanent magnet air gap, and when the permanent magnet torquer works, the silicon-based coil is fixed on the accelerometer pendulum sheet through the coil cushion block. According to the invention, the silicon-based coil is adopted to replace an enameled wire wound coil of the accelerometer permanent magnetic torquer, so that the thermal stress between the pendulous reed of the accelerometer and the coil of the permanent magnetic torquer is effectively reduced, and the viscoelasticity of the coil is reduced. The silicon-based coil has better space stability in a permanent magnetic circuit, and the scale factor stability of the accelerometer can be obviously improved.

Description

Permanent magnetic torquer for accelerometer

Technical Field

The invention belongs to the technical field of flexible pendulum accelerometers, and particularly relates to a silicon-based coil-based permanent magnet torquer for an inertial navigation accelerometer.

Background

The flexible accelerometer for inertial navigation is a core component in the inertial navigation equipment, and the temperature and time repeatability of the zero position and the scale factor directly influence the precision level of the inertial navigation. With the continuous progress of modern aerospace technology, the requirement of an inertial navigation system on an accelerometer is higher and higher, and the repeatability improvement of the scale factor of the accelerometer becomes the technical bottleneck of the horizontal improvement of the accelerometer. For a flexible pendulum accelerometer, the stability of its torquer is a key factor in determining the stability of the accelerometer scale factor.

The torquer is composed of two parts, one part is a permanent magnetic circuit composed of a permanent magnet and a yoke, and the other part is a conductive coil fixed on a pendulous reed of the accelerometer. To improve the stability of the torquer, it is necessary to improve the magnetic circuit stability of the permanent magnetic circuit and the stability of the torquer coil in space with temperature and time.

At present, a coil of a permanent magnet torquer of an accelerometer is mostly formed by winding an enameled wire, the wound coil has viscoelasticity characteristics according with materials, and meanwhile, the expansion coefficient of the wound coil is usually different from that of a pendulous reed material of the accelerometer by more than one order of magnitude, such as monocrystalline silicon, quartz and the like. After the coil is fixed on the oscillating piece of the accelerometer, the coil is subjected to thermal stress under the action of temperature and is greatly deformed, and the coil cannot return to an initial position after being subjected to stress deformation due to viscoelasticity, so that the spatial position of the coil of the torquer is permanently changed, and the repeatability of a scale factor is reduced. In order to improve the stability of the scale factor of the accelerometer, common methods include that the accelerometer adopts methods such as a framework coil, and the like, and the methods can improve the nonlinearity of the scale factor of the accelerometer to a certain extent, but the effect is very limited. The silicon-based coil has a stable structure, but has the problems of short winding length and large coil resistance, and is difficult to be directly applied to the torquer for the accelerometer.

The torquer coil for the accelerometer is usually fixed on the pendulum piece of the accelerometer through gluing, the connection mode has the problems of poor positioning consistency and large thermal stress, a cushion block can be added between the coil and the pendulum piece to control the position of the coil and reduce the thermal stress, but the effect of reducing the thermal stress between the coil and the pendulum piece by the structure effect is still very limited.

Disclosure of Invention

The invention aims to provide a permanent magnetic torquer for an accelerometer, which is used for effectively reducing the thermal stress between a pendulous reed and a coil of the permanent magnetic torquer and obviously improving the scale factor stability of the accelerometer.

The permanent magnetic torquer for the accelerometer comprises a yoke iron, a permanent magnet, a magnetic conductive sheet and a silicon-based coil, wherein the yoke iron is positioned at the bottommost part, the permanent magnet is fixed on the yoke iron, and the magnetic conductive sheet is fixed on the upper surface of the permanent magnet. A permanent magnet air gap is formed between the yoke iron and the magnetic conductive sheet, the silicon-based coil is positioned in the permanent magnet air gap, and when the permanent magnet torquer works, the silicon-based coil is fixed on the accelerometer pendulum sheet through the coil cushion block.

The fixing mode among the silicon-based coil, the coil cushion block and the accelerometer pendulous reed is bonding or glass sintering.

The coil cushion block is a monocrystalline silicon cushion block with a flexible structure so as to release thermal stress between the accelerometer pendulous reed and the coil; the flexible structure can be a supporting structure with small rigidity in the middle and large rigidity at two ends.

Wherein, in order to increase the winding length of the silicon-based coil and the lifting moment coefficient, the silicon-based coil can be a spiral structure stacked by a plurality of layers, and the spiral directions of each layer are opposite, so as to increase the winding length of the coil.

In order to reduce the resistance of the silicon-based coil and improve the conductivity of the silicon-based coil, metal can be filled in the gap of the silicon-based coil or a metal layer can be plated on the surface of the silicon-based coil, and metal eutectic fusion can also be carried out on the surface of the silicon-based coil.

According to the invention, the silicon-based coil is adopted to replace an enameled wire wound coil of the accelerometer permanent magnetic torquer, so that the thermal stress between the pendulous reed of the accelerometer and the coil of the permanent magnetic torquer is effectively reduced, and the viscoelasticity of the coil is reduced. The silicon-based coil has better space stability in a permanent magnetic circuit, and the scale factor stability of the accelerometer can be obviously improved.

Drawings

FIG. 1 is a perspective view of a permanent magnetic torquer and a pendulous reed for an accelerometer;

FIG. 2 is a sectional view of the permanent magnetic torquer and the pendulous reed for the accelerometer;

FIG. 3 is a cross-sectional view of a coil spacer in a permanent magnetic torquer for an accelerometer of the present invention;

fig. 4 is a top view of a silicon-based coil used in the permanent magnetic torquer for the accelerometer of the present invention.

In the figure:

1-yoke iron, 2-permanent magnet, 3-magnetic conductive sheet, 4-silicon-based coil, 5-permanent magnet air gap, 6-coil cushion block, 7-swinging sheet, 8-swinging sheet flexible part, 9-silicon-based coil lead terminal and 10-gap

Detailed Description

For a clearer understanding of the objects, technical solutions and advantages of the present invention, the following detailed description of the present invention will be made with reference to the accompanying drawings and embodiments.

Referring to fig. 1 and 2, the permanent magnetic torquer for the accelerometer based on the silicon-based coil comprises a yoke 1, a permanent magnet 2, a magnetic conductive sheet 3 and a silicon-based coil 4, wherein the yoke 1 is located at the bottommost part of the structure, the permanent magnet 2 is fixed on the yoke by means of glue joint and the like, and the magnetic conductive sheet 3 is fixed on the upper surface of the permanent magnet 2 by means of glue joint and the like. A permanent magnet air gap 5 is arranged between the yoke iron 1 and the magnetic conductive sheet 3, and the silicon-based coil is positioned in the permanent magnet air gap 5.

Referring to fig. 2 and 3, when the silicon-based coil permanent magnet torquer of the accelerometer works, the silicon-based coil 4 needs to be fixed on the swinging plate 7, and the swinging plate 7 and the silicon-based coil 4 are connected through the coil cushion block 6, wherein the connection mode can be bonding or glass sintering. The coil cushion block 6 is a supporting structure with small rigidity in the middle and large rigidity at two ends and is used for releasing the thermal stress between the swinging sheet and the coil. The permanent magnet 2 is magnetized along the axial direction, and the yoke iron 1 and the magnetic conductive sheet 3 guide the magnetic field generated by the permanent magnet 2 to enter the permanent magnet air gap 5 to form a magnetic field distributed along the radial direction of the magnetic conductive sheet 3. When the silicon-based coil 4 is electrified, due to electromagnetic induction, the silicon-based coil 4 will generate an acting force along the axial direction of the magnetic conductive sheet 3, and the acting force is as follows:

F＝BIL

wherein B is the magnetic field strength of the permanent magnet air gap 5, I is the energizing current of the silicon-based coil 4, and L is the length of the lead of the silicon-based coil 4. The swinging piece 7 is subjected to the moment generated by the silicon-based coil 4, the swinging piece rotates around the flexible part 8 of the swinging piece, the direction of the current in the silicon-based coil 4 determines the stress direction of the silicon-based coil 4, and the moment applying control of the swinging piece 7 based on the silicon-based coil permanent magnet torquer can be realized by adjusting the magnitude and the direction of the current in the silicon-based coil 4.

Referring to fig. 4, the silicon-based coil 4 is formed by etching single crystal silicon, and a surface insulation process is required after the silicon-based coil is processed. The silicon-based coil 4 is of a spiral structure, and is subjected to lead energization through two silicon-based coil lead terminals 9. In order to increase the coil wire length, the silicon-based coils 4 may be stacked in multiple layers to increase the coil winding length, wherein the spiral direction of each stacked silicon-based coil is opposite. In order to reduce the resistance of the silicon-based coil 4 and improve the conductivity of the silicon-based coil, metal can be filled in the gap 10 of the silicon-based coil or a metal layer can be plated on the surface of the silicon-based coil 4, and metal eutectic fusion can also be carried out on the surface of the silicon-based coil 4.

Claims

1. A permanent magnetic torquer for an accelerometer comprises a yoke (1), a permanent magnet (2), a magnetic conductive sheet (3) and a silicon-based coil (4), wherein the yoke (1) is located at the bottommost part, the permanent magnet (2) is fixed on the yoke (1), the magnetic conductive sheet (3) is fixed on the upper surface of the permanent magnet (2), a permanent magnetic air gap (5) is formed between the yoke (1) and the magnetic conductive sheet (3), the silicon-based coil is located inside the permanent magnetic air gap (5), when the permanent magnetic torquer works, the silicon-based coil (4) is fixed on an accelerometer pendulous reed (7) through a flexible coil cushion block (6), the fixing modes among the silicon-based coil (4), the flexible coil cushion block (6) and the accelerometer pendulous reed (7) are bonding or glass sintering, the silicon-based coil (4) is of a multi-layer stacked spiral structure, the spiral directions of each layer are opposite, gaps (10) of the silicon-based, the surface of the silicon-based coil (4) is plated with a metal plating layer or is subjected to metal eutectic fusion.

2. A permanent magnetic torquer for an accelerometer as claimed in claim 1 wherein the flexible coil pad (6) is a single crystal silicon pad.

3. The permanent magnetic torquer for an accelerometer of claim 2, wherein the single crystal silicon spacer is a support structure with low rigidity in the middle and high rigidity at the two ends.