CN1766647A - Magnetofluidic accelerometer with partial filling of cavity with magnetic fluid - Google Patents
Magnetofluidic accelerometer with partial filling of cavity with magnetic fluid Download PDFInfo
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- CN1766647A CN1766647A CN 200510107504 CN200510107504A CN1766647A CN 1766647 A CN1766647 A CN 1766647A CN 200510107504 CN200510107504 CN 200510107504 CN 200510107504 A CN200510107504 A CN 200510107504A CN 1766647 A CN1766647 A CN 1766647A
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- magnetic fluid
- coasting body
- sensor
- acceleration
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Abstract
A sensor comprises a housing and magnetic fluid in the housing which is partly filled by the magnetic fluid. An inertial body contacts with the magnetic fluid and moves relative to the magnetic fluid to indicate the acceleration of the housing. The acceleration is composed by linear acceleration and/or angular acceleration. Several magnets are arranged on the housing, wherein, the magnetic fluid is positioned within liquid drop among the magnets and the inertial body, being as a single liquid drop or several liquid drop between each magnet and the inertial body. The residual volume of the housing can be filled completely with non-magnetic fluid.
Description
Technical field
The present invention relates to Magnetofluidic accelerometer sensor (magnetofluidic accelerationsensor).
Background technology
Usually, the U.S. Patent application No.10/836 that submits in for example on May 3rd, 2004,624, the U.S. Patent application No.10/836 that on May 3rd, 2004 submitted to, 186, the U.S. Patent application No.10/422 that on May 21st, 2003 submitted to, 170, the U.S. Patent application No.10/209 that on August 1st, 2002 submitted to, 197 (present U.S. Patent No.s 6,731,268), the U.S. Patent application No.09/511 that on February 24th, 2000 submitted to, 831 (present U.S. Patent No.s 6,466,200), with disclosure and description among the Russ P application No.99122838 that submitted on November 3rd, 1999 Magnetofluidic accelerometer, this Magnetofluidic accelerometer uses magnetic current principle and is suspended in coasting body in the magnetic fluid, and acceleration is measured.This accelerometer generally includes the sensor case (sensor outer housing, or " container ") that is full of magnetic fluid.Coasting body (inert matter) is suspended in this magnetic fluid.This accelerometer is usually included in several drive coils (power coil) that produce magnetic field in the magnetic fluid and measures several measurement coils of the variation that produces because of relatively moving of coasting body in the magnetic field.
When power coil energising and generation magnetic field, magnetic fluid is attempted himself as close as possible power coil location.This causes coasting body to be suspended in roughly how much central authorities of shell effectively.When applying power to accelerometer (the perhaps device of installing to accelerometer), thereby when causing angular acceleration or linear acceleration, coasting body attempts to remain on the place, position.Therefore, coasting body " extruding " makes hydromagnetic distrubance and changes the Distribution of Magnetic Field of magnetic fluid inside on magnetic fluid.This variation in the Distribution of Magnetic Field detects by measuring coil, converts the value of linear acceleration and angular acceleration then to electronic device.Under the situation of knowing linear acceleration and angular acceleration values, may calculate linear speed and angular velocity by the simple mathematical computing then, and if necessary, calculate linear position and position, angle.In other words, accelerometer provide three linear degree of freedom of the information about six-freedom degree----(x, y, z) and three angles (perhaps rotation) degree of freedom (about x, y, the angular acceleration ω of z axle
x', ω
y', ω
z').
Usually, the accurate characteristic height of accelerometer relies on the geometric configuration of shell, coasting body, the setting of magnet, the attribute of magnetic fluid etc.For the deviser, wish the sensor parameters of wide region as far as possible.This parameter comprises for example dynamic range, susceptibility, and the response time, physical dimension, cost, deviation, to the susceptibility of environmental factor, or the like.One of them factor that influences sensor performance is a hydrodynamic resistance, and it is by attempting to overcome the coasting body generation that magnetic fluid moves.Usually, magnetic fluid is the fluid than viscosity, and the area that coasting body contacts with magnetic fluid is big more, and hydrodynamic resistance is big more.Therefore, higher hydrodynamic resistance causes lower frequency response.
Therefore, need to reduce the method for the hydrodynamic resistance in the Magnetofluidic accelerometer in the prior art.
Summary of the invention
The present invention relates to Magnetofluidic accelerometer, wherein magnetic fluid partly fills up cavity, and this Magnetofluidic accelerometer has been avoided the one or more problems relevant with existing accelerometer basically.
More particularly, in exemplary embodiment of the present invention, sensor comprises shell and is arranged in the magnetic fluid of shell that this magnetic fluid not exclusively fills up shell.Coasting body contacts with this magnetic fluid.Coasting body is the indication of the acceleration on the shell with respect to the displacement of magnetic fluid.This acceleration comprises linear acceleration and/or angular acceleration.This coasting body can be air bubble or not similar liquid.Several magnets are installed on the shell, and wherein magnetic fluid is positioned in the drop between magnet and the coasting body.This magnetic fluid can be the single drop between each magnet and the coasting body, or a plurality of drops between each magnet and the coasting body.Residual volume in the shell can fill up non magnetic fluid.
On the other hand, sensor comprises substantially around coasting body and is arranged on magnetic fluid in the drop.The second fluid operated by rotary motion different with magnetic fluid are between magnetic fluid and coasting body.Coasting body is the indication of acceleration on the sensor with respect to the displacement of magnetic fluid.
On the other hand, sensor comprises coasting body and several drops of magnetic fluid that coasting body keep is suspended.Several magnetic poles keep the drop of magnetic fluid to contact with coasting body.Coasting body is the indication of acceleration on the sensor with respect to the displacement of magnetic fluid.
On the other hand, the method that is used to measure acceleration comprises and uses the drop of magnetic fluid that coasting body is suspended; In response to the power that is applied on the coasting body position of coasting body is measured; Reaching with this displacement is the basic calculation acceleration.
On the other hand, the method that is used to measure acceleration comprises and uses the drop of magnetic fluid that coasting body is suspended; In magnetic fluid, produce magnetic field; Adjust magnetic field, to offset coasting body since acceleration and with respect to the drop of magnetic fluid in locational variation; Reaching with this adjusting range is the basic calculation acceleration.
Other features and advantages of the present invention will be illustrated in the following description, and some will be perfectly clear in description, perhaps can know from realization of the present invention.By the structure that in described description and claim and accompanying drawing, particularly points out, will realize and obtain advantage of the present invention.
Should be appreciated that aforesaid general introduction and following detailed are exemplary and indicative, and be desirable to provide more explanations of the present invention as claim.
Description of drawings
Accompanying drawing is illustrated embodiments of the invention, and plays the effect of explaining inventive principle jointly with instructions, and these accompanying drawings provide the further understanding to invention, merges in this instructions and has constituted its part.In the accompanying drawings:
Accompanying drawing 1 has illustrated the equal proportion 3-D view of the magnetic fluid acceleration transducer (assembledmagneto fluidic acceleration sensor) of assembling of the present invention.
Accompanying drawing 2 has illustrated the side view of this sensor, and having dismantled, one of them drives magnetic device (drive magnet assembly).
Accompanying drawing 3 has illustrated the view of partly cutting open, shows the setting that drives magnetic coil and sensing coil.
Accompanying drawing 4 has illustrated the decomposition side view of this sensor.
Accompanying drawing 5 has illustrated the three-dimensional isometric view of the sensor of accompanying drawing 4 from different viewing angles.
Accompanying drawing 6 has illustrated one embodiment of the present of invention, and this embodiment is used for each driving magnetic device with the magnetic fluid of single drop.
Accompanying drawing 7 has illustrated alternative, and wherein the magnetic fluid of a plurality of drops is used for each driving magnetic device.
Embodiment
Embodiments of the present invention is described in detail for present general, and its example is illustrated in the accompanying drawings.
Accompanying drawing 1 to 5 has illustrated the exemplary embodiment of magnetic fluid acceleration transducer of the present invention.The basic functional principle of magnetic fluid sensor is in U.S. Patent No. 6,466, is described in 200, at this it merged to come in for your guidance.The performance of this sensor is described by a series of nonlinear partial differential equations usually, referring to U.S. Provisional Patent Application No.60/614, and 415, the application requires right of priority to this provisional application.
Especially, accompanying drawing 1 has illustrated the equal proportion 3-D view of the acceleration transducer of assembling.Accompanying drawing 2 has illustrated the side view of acceleration transducer, has wherein dismantled one and has driven magnetic shell.Shown the coasting body (Inertial body) that is positioned at central authorities.
Accompanying drawing 3 has illustrated the view of partly cutting open, shows the setting that drives magnetic coil and sensing coil.Accompanying drawing 4 has illustrated the sectional side view of sensor, shows shell, the magnetic fluid in the shell and by this magnetic fluid around coasting body.Accompanying drawing 5 has illustrated the three-dimensional isometric view of sensor shown in the accompanying drawing 4 from different viewing angles.
With further reference to accompanying drawing 1, the accelerometer 102 that is in the assembling form shown in the accompanying drawing 1 comprises that shell 104 and several drive magnetic device 106A-106E, and each drives magnetic device and all uses corresponding line 110A-110E to be connected on the power supply.Note, in this view, only show five driving magnetic devices 106, but, the 6th driving magnetic device (being represented by 106F) has been described also wherein referring to accompanying drawing 4.
Accompanying drawing 2 has illustrated the sensor 102 of accompanying drawing 1, the driving magnetic device of wherein having dismantled.Under the situation that driving magnetic device 106c dismantles, can see that coasting body 202 is positioned at the roughly geometric center place of shell 104.Magnetic fluid 204 fills up the remainder of the useful volume in the shell.Note, for the sake of clarity, although these most of fluids be black and have " oiliness " sensation, do not draw magnetic fluid itself is actual in the accompanying drawings.
Accompanying drawing 3 has illustrated the view of partly cutting open, shows sensor 102.For the sake of clarity, have only some parts in accompanying drawing 3, to mark.That shown in Figure 3 is four drive coils (or magnet) 302A, 302B, 302E and 302D, is generically and collectively referred to as magnet 302 (remaining two magnet is not shown in this accompanying drawing).Magnet 302 also is referred to as levitated magnet (suspension magnet) sometimes, power magnet (power magnet), or suspended coil (suspension coil) (if using electromagnet).
In one embodiment, each this driving magnetic device 106 all has two sensing coils by 306 and 308 (being 306A, 308A, 306B, 308B, 306E, 308E, 306E, 308E in accompanying drawing 3) expression.Sensing coil 306,308 also is referred to as " sensing magnet " or " measurement coil " sometimes.Notice that further for measure linear acceleration and angular acceleration, each side of " cube " all needs two sensing coils.If have only single sensing coil to navigate to the centre of each side of " cube ", then can not the measured angular acceleration.As not being best selection, cubical each side may only be used a sensing coil, but its offset from center is provided with.Yet in this case, it is obviously complicated more that mathematical analysis becomes.
Attached Figure 4 and 5 have illustrated " decomposition " view of sensor 102, show same structure from two different angles.Especially, be one of them decomposition view that drives magnetic device 106D shown in the attached Figure 4 and 5.As shown in the accompanying drawings, drive magnetic device 106D and comprise case 402, bonnet 404, drive coil 302D, two sensing coil 306D and 308D, magnetic core 406 (each sensing coil 306D and 308D have) and drive magnetic core 408.In alternative, magnetic core 406 and 408 can be fabricated to single general part (in fact, as single " transformer core ").
In the present embodiment, sensing coil 306D and 308D are positioned at drive coil 302D inside, and bonnet 404 remains on drive coil 302D and sensing coil 306D and 308D on the position among the drive coil device 106D.
Magnet 302 is used for coasting body 202 maintenances are suspended in the roughly geometric center place of shell 104.The magnetic flux change that sensing coil 306,308 is measured in the shell 104.Magnetic fluid 204 attempts to flow to the strongest position, magnetic field.This has caused the repulsive force to coasting body 202, and this coasting body is generally non magnetic or part magnetic (promptly the magnetic than magnetic fluid 204 is little).
Magnetic fluid 203 is high magnetic, and attractive to magnet 302.Therefore, by attempting to be positioned as close to magnet 302, magnetic fluid effectively with coasting body 202 away from magnet 302 " release " or repel.Basic identical in all magnet 302, perhaps all magnet 302 apply essentially identical power and magnet 302 about under the coasting body 202 symmetrically arranged situations, and coasting body 202 will tend to be positioned at the geometric center place of shell 104.This effect can think to repel magnetic force (although coasting body 202 can directly not be activated magnet 302 influences in the reality, can be subjected to remote effect by magnetic fluid 204).
An example of magnetic fluid 204 is wherein to be dissolved with iron oxide (Fe
3O
4) kerosene.Magnetic fluid 204 is a colloidal suspension.This Fe
3O
4The general diameter of particle is the order of magnitude of 10 to 20 nanometers (perhaps littler).This Fe
3O
4Particle is being generally spherical in shape, and plays the effect of magnetic dipole when applying magnetic field.
More generally, magnetic fluid 204 can use other feeromagnetic metal, as cobalt, gadolinium, nickel, dysprosium and iron, and their oxide, for example Fe
3O
4, FeO
2, Fe
2O
3, and magnetic compound, as MnZn acid iron (Zn
xMn
1-xFe
2O
4), vectolite, or other ferromagnetic alloy, oxide and ferrite.Simultaneously, except kerosene, water or oil also can be used as base fluid (base liquid).
Accompanying drawing 6 has illustrated one embodiment of the present of invention.Accompanying drawing 6 shows sensor illustrated in the accompanying drawing 1 to 5 with cut-open view, wherein the magnetic fluid of several drops coasting body 202 that is used to suspend.For the sake of clarity, have only some element to mark in the accompanying drawing 6.As shown in accompanying drawing 6, single drop (mark with 620A, 620D, 620E and 620B in accompanying drawing 6, four in six drops wherein have been shown in this accompanying drawing) is used for each and drives magnetic device 106.Simultaneously, for the sake of clarity, the cavity that coasting body 202 is positioned at or " clearance spaces " are by 622 expressions in accompanying drawing 6.Except drop 620 and coasting body 202, cavity 622 can be full of air or some other gas.Perhaps, the remainder of the volume of cavity 622 can be full of the second liquid (not shown).This second liquid is preferably nonmagnetic, thereby it is not easy to mix with magnetic fluid.Notice that further this second liquid not similar with magnetic fluid can self be used as coasting body, rather than " solid-state " coasting body 202 shown in the accompanying drawing.Simultaneously, air bubble can be used as coasting body and (in other words, remove the coasting body 202 shown in the accompanying drawing 6 basically, and sensing coil detect drop 620 " rocking ".
Be noted that also and have only when magnet 302 applies magnetic field that drop 620 just roughly has the shape shown in the accompanying drawing 6.Lacking under the situation in magnetic field, all magnetic fluids 204 are with one of them corner of " injecting (pool) " cavity 622.Generally, preferably use permanent magnet as magnet 302, the combination of perhaps using permanent magnet and electromagnet is as magnet 302, in particular for the assembling purpose, thereby avoid the possibility of concentrating synthetic (pooling) of magnetic fluid 204, and guarantee situation shown in drop 620 formation.
Also be noted that magnetic fluid 204 can be whole sensor 102 than expensive component.So, wish to reduce the amount of magnetic fluid 204 sensor 102 from the angle of saving cost.Simultaneously, as mentioned above, hydrodynamic resistance depends on the contact area between coasting body 202 and the magnetic fluid 204.If magnetic fluid 204 is arranged to the form of drop 620, the contact area between magnetic fluid 204 and the coasting body 202 reduces, and improves the frequency characteristic of sensor 102.
Accompanying drawing 7 has illustrated another embodiment of the present invention, wherein drives magnetic device 106 and used a plurality of drops for each, rather than single drop 620.These drops are corresponding 626A, 624A, 626B, 624B or the like of being labeled as in accompanying drawing 7.Although shown in Figure 7 each drive two drops of magnetic device 106, but according to needed characteristic, the Distribution of Magnetic Field that the setting of magnet 302 and magnet 302 are produced can be used for more a plurality of this drops each and drive magnetic device 106, for example three or four.As shown in Figure 6, the residual volume in the cavity 622 can fill up air, gas, second liquid or the like.
By description, it will be apparent to those skilled in the art that some advantage that has obtained described method and apparatus to the embodiment of the invention.Also will be appreciated that, within scope and spirit of the present invention, can make various modifications, adaptations and alternative thereof.The present invention is further limited by claims.
Claims (17)
1. sensor comprises:
Shell;
Magnetic fluid in the shell, this magnetic fluid not exclusively fills up shell; And
The coasting body that contacts with this magnetic fluid,
Wherein coasting body is the indication of the acceleration on the shell with respect to the displacement of magnetic fluid.
2. sensor as claimed in claim 1 is characterized in that acceleration comprises linear acceleration.
3. sensor as claimed in claim 1 is characterized in that acceleration comprises angular acceleration.
4. sensor as claimed in claim 1 is characterized in that, this coasting body is an air bubble.
5. sensor as claimed in claim 1 is characterized in that, this coasting body is the drop with the not similar liquid of magnetic fluid.
6. sensor as claimed in claim 1 is characterized in that, also comprises a plurality of magnets that are installed on the shell, and wherein magnetic fluid is positioned in the drop between magnet and the coasting body.
7. sensor as claimed in claim 6 is characterized in that, magnetic fluid comprises the single drop between each magnet and the coasting body.
8. sensor as claimed in claim 6 is characterized in that, magnetic fluid comprises a plurality of drops between each magnet and the coasting body.
9. sensor as claimed in claim 1 is characterized in that the residual volume in the shell is full of non magnetic fluid.
10. sensor comprises:
Be arranged on the basic magnetic fluid in the drop around coasting body; And
Second fluid different with magnetic fluid, this second fluid is substantially disposed between magnetic fluid and the coasting body,
Wherein the displacement of coasting body is the indication of the acceleration of sensor.
11. sensor as claimed in claim 10 is characterized in that, coasting body is an air bubble.
12. sensor as claimed in claim 10 is characterized in that, coasting body is the drop with the not similar liquid of magnetic fluid.
13. sensor as claimed in claim 10 is characterized in that, also comprises shell and is installed in a plurality of magnets on the shell, wherein drop is between magnet and coasting body.
14. sensor as claimed in claim 13 is characterized in that, magnetic fluid comprises the single drop between each magnet and the coasting body.
15. sensor as claimed in claim 13 is characterized in that, magnetic fluid comprises a plurality of drops between each magnet and coasting body.
16. a sensor comprises:
Coasting body;
The a plurality of drops that keep the magnetic fluid of coasting body suspension; And
A plurality of magnetic poles that the drop of magnetic fluid is held in place,
Wherein coasting body is the indication of the acceleration on the sensor with respect to the displacement of magnetic fluid.
17. a method that is used to measure acceleration comprises:
Adopt the drop of magnetic fluid that coasting body is suspended;
In response to the power that is applied on the coasting body, the position of coasting body is measured; Reaching with this displacement is the basic calculation acceleration.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US61222704P | 2004-09-23 | 2004-09-23 | |
| US60/612,227 | 2004-09-23 | ||
| US60/613,723 | 2004-09-29 | ||
| US11/033,513 | 2005-01-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1766647A true CN1766647A (en) | 2006-05-03 |
Family
ID=36742648
Family Applications (4)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200510107507 Pending CN1776433A (en) | 2004-09-23 | 2005-09-23 | Housing for magnetofluidic accelerometer |
| CN 200510107504 Pending CN1766647A (en) | 2004-09-23 | 2005-09-23 | Magnetofluidic accelerometer with partial filling of cavity with magnetic fluid |
| CN 200510107506 Pending CN1776431A (en) | 2004-09-23 | 2005-09-23 | Magnetofluidic accelerometer with active suspension |
| CN 200510107505 Pending CN1776435A (en) | 2004-09-23 | 2005-09-23 | Magnetofluidic accelerometer with real-time correction |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200510107507 Pending CN1776433A (en) | 2004-09-23 | 2005-09-23 | Housing for magnetofluidic accelerometer |
Family Applications After (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200510107506 Pending CN1776431A (en) | 2004-09-23 | 2005-09-23 | Magnetofluidic accelerometer with active suspension |
| CN 200510107505 Pending CN1776435A (en) | 2004-09-23 | 2005-09-23 | Magnetofluidic accelerometer with real-time correction |
Country Status (1)
| Country | Link |
|---|---|
| CN (4) | CN1776433A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101246184B (en) * | 2007-02-15 | 2011-03-23 | 华南理工大学 | Quasi-two-dimension magnetic fluid acceleration transducer |
| CN103344786A (en) * | 2013-06-21 | 2013-10-09 | 浙江大学 | Method using static electricity supporting type differential capacitance method to measure three-dimensional acceleration |
| CN108548940A (en) * | 2018-06-22 | 2018-09-18 | 西安交通大学 | A kind of acceleration transducer |
| CN110104220A (en) * | 2019-05-08 | 2019-08-09 | 北京理工大学 | A kind of fluid-type reaction device |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6059229B2 (en) * | 2011-09-02 | 2017-01-11 | コーニンクレッカ フィリップス エヌ ヴェＫｏｎｉｎｋｌｉｊｋｅ Ｐｈｉｌｉｐｓ Ｎ．Ｖ． | Bed exit monitoring device |
| CN103453896B (en) * | 2013-09-13 | 2015-12-23 | 天津大学 | A kind of Magnetic-fluid gyroscope |
| CN103727935A (en) * | 2013-12-31 | 2014-04-16 | 天津大学 | Triaxial magnetofluid gyroscope |
| US10649043B2 (en) * | 2014-04-28 | 2020-05-12 | Infineon Technologies Ag | Magnetic field sensor device configured to sense with high precision and low jitter |
| CN105738653B (en) * | 2016-02-18 | 2019-01-29 | 三峡大学 | High-precision optical is displaced magnetic suspension accelerometer |
| CN105675920B (en) * | 2016-02-18 | 2018-11-13 | 三峡大学 | Quiet magnetic suspension accelerometer in high precision |
| CN107942096B (en) * | 2017-10-11 | 2019-11-19 | 杭州电子科技大学 | Three-dimensional magnetic suspension accelerometer and its manufacturing method |
-
2005
- 2005-09-23 CN CN 200510107507 patent/CN1776433A/en active Pending
- 2005-09-23 CN CN 200510107504 patent/CN1766647A/en active Pending
- 2005-09-23 CN CN 200510107506 patent/CN1776431A/en active Pending
- 2005-09-23 CN CN 200510107505 patent/CN1776435A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101246184B (en) * | 2007-02-15 | 2011-03-23 | 华南理工大学 | Quasi-two-dimension magnetic fluid acceleration transducer |
| CN103344786A (en) * | 2013-06-21 | 2013-10-09 | 浙江大学 | Method using static electricity supporting type differential capacitance method to measure three-dimensional acceleration |
| CN108548940A (en) * | 2018-06-22 | 2018-09-18 | 西安交通大学 | A kind of acceleration transducer |
| CN110104220A (en) * | 2019-05-08 | 2019-08-09 | 北京理工大学 | A kind of fluid-type reaction device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1776431A (en) | 2006-05-24 |
| CN1776433A (en) | 2006-05-24 |
| CN1776435A (en) | 2006-05-24 |
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