CN102813515A - Method and system for positioning planar remote target based on single magnetic field sensor array - Google Patents

Abstract

The invention provides a method for positioning a planar remote target based on a single magnetic field sensor array. The method comprises the following working steps: step 1, putting a positioning target with a magnetic field in a target area, and putting a magnetic field sensor array to detect a target magnetic field; step 2, putting the target area near a magnetic field sensor array plane; step 3, finding out a point (with the strongest planar magnetic field strength) inside the planar magnetic field by using a magnetic field sensor; step 4, supposing that the point with the strongest spatial magnetic field strength is located at one position A, enabling a tangent plane of a magnetic induction strength curve to go by the point; and step 5, calculating a middle point B of the magnetic field by using equations, and finally calculating a spatial coordinate position of the point with the largest supposed magnetic field strength in the step 4 through a solving equation set in combination with a surface vector equation of the curve and a normal vector of the strongest magnetic field through which the tangent plane passes. With the adoption of the method, the defect in traditional remote positioning is avoided, and the method has the advantages of accurate positioning, low cost, high efficiency and the like.

Description

Based on single array of magnetic field plane remote object localization method and system

Technical field

The present invention relates to the magnetic field localization method, be specifically related to a kind of based on single array of magnetic field plane remote object localization method and system.

Background technology

Exploration wireless medical capsule is widely known by the people in medical profession.This exploration capsule can be beamed back one with data and place external reception and recording equipment.The patient swallows this capsule in the abdomen, and it will move ahead along digestive tract, collects and transmit data on the way to receiving and recording equipment.Generally speaking, after one to two day, this disposable capsule will excrete with Excreta, and will get off to be used for to analyze and/or storage transmission such as data record such as body temperature, pH value, blood pressure and haulage times.Generally the approval wireless medical capsule that is equipped with photographic head can be used for images acquired in the industry, and the capsule that has a medicine reservoir then can be with the drug release of various various dose each zone to digestive system.

Deployment and detection are used in, and miniature probe or pick off airtight, that can't visit perhaps remote space scouting are very useful in many environment.And the position of in deployment, confirming object is the comparison difficulty, and in the plurality of applications process, the volume of target environment possibly be no more than several cubic decimeters.However, people still can accurately locate a minimum target as much as possible, like probe or pick off.Remote sensing technology is widely used in fields such as industry or medical treatment by people; For example, as wireless capsule commonly used in the present medical field be wriggling get into gastral, and in this process; Capsular particular location is unknowable, or only can be similar to and know its Position Approximate.Same, in non-armarium, the probe capsule is to be brought into by fluid or action of gravity, is example with the tubing, only can know the position that it is general in the time of confirming.The shortage of positional information is a defective of present wireless capsule technology.For example, the doctor can't be known the pathological characters by this data show when the capsular data of inspection ex vivo, like the particular location of intestinal canal tumour.And for the exact position of detecting the problem place usually needs extra position fixing process, even need operation to accomplish.

In the middle of armarium now, some magnetic location technologies have appearred.Wherein a kind of is the patent of being developed by U.S. Acker 5,558,091, and it is to be utilized in the embedded magnetic sensor ligand external magnetic field work in the capsule in the body, thereby realizes following the trail of in the body.Though this method possibly be useful to a certain extent, it does not consider the interference effect in the extra magnetic field that possibly produced by electric current and ferromagnetic material such as earth's magnetic field or those.Another kind method then is 6,216, No. 028 patent by the Haynor of U.S. exploitation, and it is installed in Magnet such as on the such medical apparatus and instruments of probe tip, replants in the patient body, utilizes external sensor Distribution of Magnetic Field to reach localized effect then.This method proposes to use four magnetic sensors to measure at X, and the magnetic field of Y and Z axle is come modeling with the tip, magnetic field as magnetic dipole, confirms the position of magnetic dipole through finding the solution Nonlinear System of Equations.Because related complexity of the calculation, this method need sizable computing capability and/or great amount of time to accomplish.And the complexity of this method has also greatly increased the probability of error.

Be used for accurately judging the improved method and system of remote object position; As to locate wireless capsule and probe etc. be highly effective; And it has great advantage, and it can be exactly accurately matees the image that is detected or other parameter such as pH value, body temperature, blood pressure etc. with the position.And it is accurately instructing drug dose, is taking to have more potentiality and advantage aspect biopsy and the post-operative recovery.And aspect non-medical use, it can be used for pipe detection or liquid processing system.When capsule or probe are used in combination with the motor control ability, in time detect probe or capsular position and just become very favourable.Owing to above-mentioned and other reason, and its some potential advantages, utilize the improved localization method in magnetic field and system to possess greatly application prospect in application.

The applicant has applied for simultaneously that also name is called two patents of invention of " based on two array of magnetic field plane remote object localization method and system " and " based on being no less than four array of magnetic field plane long range positioning method and system "; Though similar from seeing method therefor nominally, used in fact principle and method and emphasis are all different.The present invention combines solid geometry and Algebraic Equation set to find out impact point smoothly through a field intensity maximum point; And " based on two array of magnetic field plane remote object localization method and system " finds out impact point through two field intensity maximum points and magnetic torque, incorporated physics principle; And " based on being no less than four array of magnetic field plane long range positioning method and system " is through finding out the point more than four and four; The point that to find out again is linked to be line; Find out intersection point at last again, ideally transfer the problem of solid geometry the problem of plane geometry to, make it to be readily solved.In sum, three kinds of method and system likeness in form and god are not seemingly, and is each has something to recommend him, needs us to combine concrete problem concrete analysis, then which kind of method and system of decision utilization.

Summary of the invention

The technical problem that the present invention will solve is to overcome existing defective; The target area is positioned near the array of magnetic field plane; Find out the strongest point of field intensity in the plane, utilize the information of electromagnetism, the compensation of mathematical knowledge combined magnetic field to position again remote object.The method not only is fit to open environment, is equally applicable to enclosed environment, like digestion, liquid handling pipeline or some mechanical system.This method has been abandoned the drawback of traditional long range positioning, has accurate positioning, low, the efficient advantages of higher of cost.

In order to solve the problems of the technologies described above, the invention provides following technical scheme:

The present invention is based on single array of magnetic field plane remote object localization method and system, comprise following localization method:

Step 1, the anchored object that will contain magnetic field are placed in the target area, place the magnetic sensor array with detection of a target magnetic field;

Step 2, the target area is positioned near the array of magnetic field plane;

Step 3, utilize magnetic field sensor to find out that the strongest in the field intensity of plane point;

The point of step 4, hypothesis space magnetic field intensity maximum waits incisal plane of magnetic induction curve through this point, normal vector (0,0,1) in a certain position A (0,0,0);

Step 5, utilize formula $B(x,y,z)=\sqrt{B_x^2+B_{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="HDA00001835791800022.png"\; state="\{\{state\}\}">y</figure-callout>}}^2+B_z^2}=\frac{{\mathrm{\&mu;}}_0}{4\mathrm{\&pi;}{r}^4}\sqrt{3{\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="HDA00001835791800022.png"\; state="\{\{state\}\}">Q</figure-callout>}}^2+m^2{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA00001835791800022.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}$

Calculate magnetic field mid point B (x, y, z), and binding curve equation Q=[m _x(x-x ₀)+m _y(y-y ₀)+m _z(z-z ₀)]

$r=\sqrt{{(x-x_0)}^2+{(y-y_0)}^2+{(z-z_0)}^2}$ , the surperficial vector formula of last binding curve $F(x,y,z)=\frac{{\mathrm{\&mu;}}_0}{4\mathrm{\&pi;}{r}^4}\sqrt{3{\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="HDA00001835791800022.png"\; state="\{\{state\}\}">Q</figure-callout>}}^2+m^2{r}^2}-B$

$B_x=\frac{{\mathrm{\&mu;}}_0}{4\mathrm{\&pi;}}\frac{3Q(x-x_0)-m_x{r}^2}{r^5}$ And the incisal plane crosses the normal vector (0,0,1) of high-intensity magnetic field, can calculate the space coordinates position of the magnetic field intensity maximum point of supposing in the step 4 through the solving equation group;

Step 6, according to the numerical value that step 5 obtains, combine the background magnetic field compensation sensor to revise the bearing data in local measurement magnetic field again, just can draw at last the ready position of required anchored object.

Further, the target area in the said step 1 not only comprises open area, and comprises enclosed areas, such as the digestive tract of human body.

The localized system of remote object comprises required localized object, magnetic sensor array, magnetic field space analytical equipment and background magnetic field compensation sensor based on single array of magnetic field plane; Said magnetic sensor array comprises an on-fixed array of magnetic field plane, a Hall element, a magnetoresistive transducer.

Further, said required localized object itself should have magnetic field, as contains the capsule or the probe of permanent magnet.

The invention provides based on single array of magnetic field plane remote object localization method and system; The target area is positioned near the array of magnetic field plane; Find out the strongest point of field intensity in the plane, utilize the information of electromagnetism, the compensation of mathematical knowledge combined magnetic field to position again remote object.The method not only is fit to open environment, is equally applicable to enclosed environment, like digestion, liquid handling pipeline or some mechanical system.This method has been abandoned the drawback of traditional long range positioning, has accurate positioning, low, the efficient advantages of higher of cost.

Description of drawings

Accompanying drawing is used to provide further understanding of the present invention, and constitutes the part of description, is used to explain the present invention with embodiments of the invention, is not construed as limiting the invention.In the accompanying drawings:

Fig. 1 is the macrostructure sketch that the present invention is based on single array of magnetic field plane remote object localization method and system;

Fig. 2 be the present invention is based on single array of magnetic field plane remote object localization method and system supply to replace the diagram example;

Fig. 3 is that the present invention is based on single array of magnetic field plane remote object localization method and system extra supplies the planar preferred orientation method and system of the single array of magnetic field diagram example of replacing;

Fig. 4 is that the present invention is based on single array of magnetic field plane remote object localization method and system extra supplies the planar preferred orientation method and system of the single array of magnetic field diagram example of replacing;

Shown in Figure 5 is planar magnetic-field measurement of single array of magnetic field and location notion diagram.

The specific embodiment

Below in conjunction with accompanying drawing the preferred embodiments of the present invention are described, should be appreciated that preferred embodiment described herein only is used for explanation and explains the present invention, and be not used in qualification the present invention.

Fig. 1 is the macrostructure sketch based on single array of magnetic field plane remote object localization method and system.In the operating environment [10] (the non-part that should invent), such as the patient, or narrow environment has a sensor array [12] on a particular configuration, to insert each other as in machinery, liquid handling and the hydraulic system, and this structure will be further in this explanation.Sensor array [12] comprises one or more independently sensor units [14], and be evenly distributed on and operating environment [10] on target area [16] the corresponding sensor plane.Sensor array [12] can be connected with suitable computer or data handling equipment [18] and be used for showing in real time result of calculation.Capsule [20] or probe are more suitable for being installed in the inside of target area [16].As a kind of armarium, it can be swallowed by people or animal; And in the middle of some other equipment, capsule then can be inserted in the sealing constrained environments such as pipeline, tank body or other conduits, mechanical Feng Cang.And under above-mentioned various conditions, the remote sensing system all can play effectiveness.Capsule [20] comprises a dipole magnetic field, and this magnetic field is preferably produced by permanent magnet.As a capsular part, the dipole magnetic field is represented by embedded image, shown in formula 1:

$B(r,\mathrm{\&theta;})=\frac{{\mathrm{\&mu;}}_{0}m}{4\mathrm{\&pi;}{\mathrm{<figure-callout\; id="3"\; label="r"\; filenames="HDA00001835791800022.png"\; state="\{\{state\}\}">r</figure-callout>}}^3}\sqrt{1+3{\mathrm{<figure-callout\; id="2"\; label="Cos"\; filenames="HDA00001835791800022.png"\; state="\{\{state\}\}">Cos</figure-callout>}}^2\mathrm{\&theta;}}$ (formula 1)

Sensor unit [14] comprises hall effect sensor, and its output voltage changes along with the variation in magnetic field; And magnetic resistance sensor, its resistance also changes along with the variation of external magnetic field.Effective investigative range of Hall element is very big, and magnetoresistive transducer then has higher detection accuracy.Magnetic sensor or combination sensor as for other types also can use under the condition that does not break away from the principle of the invention.The typical case of system representative promptly is the field adaptability magnetic sensor of the common on the market 2mm of being of a size of x2mm at present in the organism.For example, the array of 5mm 2mm outside array of magnetic field when it detects magnetic field intensity and is 0.01 Gauss, uses the spatial resolution of these method and system can reach 0.05mm.Therefore, the position in magnetic field like magnetic dipole or capsule [20], can accurately be surveyed in the 1mm scope.In order to make the target area of being scanned greater than sensor array, simultaneously/or need an array in order to reduce the monomeric quantity of pick off, sensor array then can be moved into the target area so, and vice versa.The mobile best plane of magnetic sensor and/or target area along the sensor array place, and preferably operate according to mechanical guide, carry out along correct direction under the propelling of automatic or manpower to guarantee it.

In addition, owing to position the compensation that has taken into account magnetic field value in the calculation process at this, positioning accuracy also is improved.Such as the value in earth's magnetic field possibly be stored and be used to revise the capsule position of calculating gained based on magnetic field sensor.And field compensation pick off [22] can be used to survey the real offset in the magnetic field under certain position and the condition, the for example influence in earth's magnetic field, magnetic material or faradic magnetic field.Capsular position data is preferably by the field compensation data correction, and field compensation pick off [22] preferably is placed in the position of detection less than capsule [20] magnetic field.As everyone knows, the spatial parameter of the sensor unit [14] of sensor array [12] constant preferably.

A typical case of the present invention is as shown in Figure 2: single array of magnetic field plane [12] is used for through field curve is analyzed, can releasing the strongest condition of field intensity to capsule [20] location.What following Nonlinear System of Equations 2 to 5.6 was represented is the position and the amount of owing direction of being found the solution dipole by induced field.

$B(x,y,z)=\sqrt{B_x^2+B_{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="HDA00001835791800022.png"\; state="\{\{state\}\}">y</figure-callout>}}^2+B_z^2}=\frac{{\mathrm{\&mu;}}_0}{4\mathrm{\&pi;}{r}^4}\sqrt{3{\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="HDA00001835791800022.png"\; state="\{\{state\}\}">Q</figure-callout>}}^2+m^2{r}^2}$ (formula 2)

Q＝[m _x(x-x ₀)+m _y(y-y ₀)+m _z(z-z ₀)]

$r=\sqrt{{(x-x_0)}^2+{(y-y_0)}^2+{(z-z_0)}^2}$

$F(x,y,z)=\frac{{\mathrm{\&mu;}}_0}{4\mathrm{\&pi;}{r}^4}\sqrt{3{\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="HDA00001835791800022.png"\; state="\{\{state\}\}">Q</figure-callout>}}^2+m^2{r}^2}-B$ (formula 3)

$(\frac{\&PartialD;F}{\&PartialD;x},\frac{\&PartialD;F}{\&PartialD;y},\frac{\&PartialD;F}{\&PartialD;z})$ (formula 4)

$\frac{\&PartialD;F}{\&PartialD;x}=0$ (formula 5.1), $\frac{\&PartialD;F}{\&PartialD;y}=0$ (formula 5.2), $\frac{\&PartialD;F}{\&PartialD;z}=1$ (formula 5.3)

$B_x=\frac{{\mathrm{\&mu;}}_0}{4\mathrm{\&pi;}}\frac{3Q(x-x_0)-m_x{r}^2}{r^5}$ (formula 5.4)

$B_y=\frac{{\mathrm{\&mu;}}_0}{4\mathrm{\&pi;}}\frac{3Q(y-y_0)-m_y{r}^5}{r^5}$ (formula 5.5)

$B_z=\frac{{\mathrm{\&mu;}}_0}{4\mathrm{\&pi;}}\frac{3Q(z-z_0)-m_z{r}^2}{r^5}$ (formula 5.6)

If hypothesis magnetic field intensity maximum an A (0,0, O), wait the incisal plane (z=0) of magnetic induction curve Q to cross some A and normal vector (0,0,1).(x, y z) are provided by formula 2 magnetic field mid point B, and the equation of locus of curve Q is provided by formula 3, and the surface amount of owing of curve is provided by formula 4.And for the normal vector of crossing some A on the incisal plane, formula 5.1-5.6 can solve its six unknown parameters, and note is made x0, y0, and z0, mx, my and mz, representing magnetic dipole respectively is the position and the direction of capsule [20].

Another typical case of this invention is shown in Fig. 3 and 4: confirm magnetic field position with single array of magnetic field plane [12].In the method, Nonlinear System of Equations (formula 2-5.6) utilizes magnetic moment to find the solution that more succinct rapidly and this method can the same a kind of method be used in combination, and needn't know the size of magnetic moment, because must be known in a kind of method of this parameter pro-.

(formula 6.1)

(formula 6.2)

(formula 6.3)

Tan (β+α)=2 ^2/3Tan α (formula 6.4)

Magnetic dipole is at point (0 in the hypothetical examples; 0; 0) prescription is to along the z direction of principal axis, and incisal plane normal n crosses the maximum value of magnetic field B point that records, by geometrical symmetry; High field vector B and normal vector n and the vectorial m of dipole moment are in the same plane, and this just is converted into the three-dimensional localization problem effectively and is the two-dimensional localization problem.The angle of vector B and vector n is

, can be obtained by sensing data.For addressing this problem, maximum field vector and the magnetic dipole vector that will at first confirm α and β value, gained are shown in dotted line among Fig. 3, and accounting equation is 6.1 and 6.2.First angle equation (formula 6.3 and 6.4) derives from the topological transformation among Fig. 4, is the space along the linear geometric transformation definition of the solid of z direction shown in the dotted line.Curved surface by the dipole field equation obtains on the z axle can be regarded a spheroid as, and the topological structure characteristic as the point of contact then remains unchanged.Based on the geometrical relationship of each point, can obtain α and β value by formula 6.3-6.4, and definite dipole direction.If magnetic moment m is known, utilize formula 2 or formula 3, can confirm distance R, R represents the position of dipole.Additive method is simpler, more effective relatively on calculating for this method, and particularly it can confirm instantaneous position, like the controlled motion of real-time detection system and/or capsule and probe.

Shown in Figure 5 is planar magnetic-field measurement of single array of magnetic field and location notion diagram.Magnetic field sensor (among the figure [HMC5843]) evenly is embedded on the circuit board, and line number and columns can confirm with application request, and like 10*10, the sensor array on circuit board can be measured and confirm a H plane.This circuit board is by I ²C is parallel to be connected on the nRFLE1, again with the magnetic field data that records through being wirelessly transmitted to nRFLU1, the magnetic field of further handling can be connected to pc port through USB interface, realizes real-time positioning and monitoring to target through display screen.With respect to four magnetic field sensor plane positioning systems and two magnetic field sensor plane positioning systems; This system further is reduced to one with required H plane number; On algorithm, slightly have any different; But date processing when not influencing practical application and transmission speed, and can reach demand equally to the real-time positioning of target.And reduce the minimizing that H plane means the circuit board quantity that is inlaid with magnetic field sensor, also can reach the purpose of further saving cost.

The method and system of this invention have plurality of advantages, as: utilize based on the measurement in magnetic field and analyze accurate location remote object, high efficiency, low cost etc., it also has some other advantage in addition.When this invention was specialized by practical application, its meaning just had been not limited only to this.For example, in the practical application, do not breaking away under some specified conditions of the principle of the invention, material and step can change and reconfigure.Though say with regard to plane or plane geometry this respect, what mention here all is that now main flow is selected, if adopt the present invention, substitutes the plane with curved surface, and calculating according to selected curvature also is feasible in practical application.In addition, on the basis that does not deviate from the principle of the invention, the peaked method of calculating is applicable to too finds the solution minima or optional intermediate value.With reference to accompanying drawing and related description, for professional person in the industry, these examples and some other applying examples based on this invention, correction wherein, combination and other advantage all are conspicuous.

The above is merely the preferred embodiments of the present invention; Be not limited to the present invention; Although the present invention has been carried out detailed explanation with reference to previous embodiment; For a person skilled in the art, it still can be made amendment to the technical scheme that aforementioned each embodiment put down in writing, and perhaps part technical characterictic wherein is equal to replacement.All within spirit of the present invention and principle, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (4)

1. based on single array of magnetic field plane remote object localization method, it is characterized in that comprising following job step:

Step 1, the anchored object that will contain magnetic field are placed in the target area, place the magnetic sensor array with detection of a target magnetic field;

Step 2, the target area is positioned near the array of magnetic field plane;

Step 3, utilize magnetic field sensor to find out that the strongest in the field intensity of plane point;

The point of step 4, hypothesis space magnetic field intensity maximum waits incisal plane of magnetic induction curve through this point, normal vector (0,0,1) in a certain position A (0,0,0);

Step 5, utilize formula $B(x,y,z)=\sqrt{B_x^2+B_y^2+B_z^2}=\frac{{\mathrm{\&mu;}}_0}{4\mathrm{\&pi;}{r}^4}\sqrt{3Q^2+m^2{r}^2}$

Calculate magnetic field mid point B (x, y, z), and binding curve equation Q=[m _x(x-x ₀)+m _y(y-y ₀)+m _z(z-z ₀)]

$r=\sqrt{{(x-x_0)}^2+{(y-y_0)}^2+{(z-z_0)}^2}$ , the surperficial vector formula of last binding curve $F(x,y,z)=\frac{{\mathrm{\&mu;}}_0}{4\mathrm{\&pi;}{r}^4}\sqrt{3Q^2+m^2{r}^2}-B$

$B_x=\frac{{\mathrm{\&mu;}}_0}{4\mathrm{\&pi;}}\frac{3Q(x-x_0)-m_x{r}^2}{r^5}$ And the incisal plane crosses the normal vector (0,0,1) of high-intensity magnetic field, can calculate the space coordinates position of the magnetic field intensity maximum point of supposing in the step 4 through the solving equation group;

Step 6, according to the numerical value that step 5 obtains, combine the background magnetic field compensation sensor to revise the bearing data in local measurement magnetic field again, just can draw at last the ready position of required anchored object.

2. according to claim 1 based on single array of magnetic field plane remote object localization method, it is characterized in that: the target area in the said step 1 not only comprises open area, and comprises enclosed areas.

3. comprise required localized object, magnetic sensor array, magnetic field space analytical equipment and background magnetic field compensation sensor based on the described single array of magnetic field of claim 1 plane remote object localization method; Said magnetic sensor array comprises an on-fixed array of magnetic field plane, a Hall element, a magnetoresistive transducer.

4. according to claim 3 based on single array of magnetic field plane remote object navigation system, it is characterized in that: said localized object itself should have magnetic field.

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