CN106969750B - Magnetic liquid omnibearing horizontal inclination angle sensor - Google Patents
Magnetic liquid omnibearing horizontal inclination angle sensor Download PDFInfo
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- CN106969750B CN106969750B CN201710321011.3A CN201710321011A CN106969750B CN 106969750 B CN106969750 B CN 106969750B CN 201710321011 A CN201710321011 A CN 201710321011A CN 106969750 B CN106969750 B CN 106969750B
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- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C9/00—Measuring inclination, e.g. by clinometers, by levels
- G01C9/18—Measuring inclination, e.g. by clinometers, by levels by using liquids
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C9/00—Measuring inclination, e.g. by clinometers, by levels
- G01C9/18—Measuring inclination, e.g. by clinometers, by levels by using liquids
- G01C2009/187—Measuring inclination, e.g. by clinometers, by levels by using liquids magnetic, e.g. ferromagnetic
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Abstract
The invention relates to a magnetic liquid omnibearing horizontal tilt angle sensor, which comprises a magnetic liquid measuring element, a bracket, a horizontal base and a stacked permanent magnet; the magnetic liquid measuring element comprises a closed spherical shell, three tunneling magneto-resistance (TMR) sensors, a connecting rod, a connecting ring and magnetic liquid; the sealed spherical shell is filled with magnetic liquid accounting for 40-50% of the volume of the spherical shell and stacked permanent magnets, and is connected with the connecting ring through a connecting rod. The sensor solves the problem of non-uniform change rate of the magnetic induction intensity B along with the change of the inclination angle through the design of the stacked permanent magnets, and remarkably improves the measurement precision and the stability of the sensor. The sensor solves the problem of a reference object of the deflection direction through the design of the compass on the horizontal base, and increases the normalization of the measured value of the deflection direction angle.
Description
Technical Field
The invention relates to an inclination angle sensor, in particular to an inclination angle sensor adopting magnetic liquid.
Background
With the continuous progress of science and technology, the inclination angle of a working plane relative to the horizontal plane is required to be accurately measured in social production practice, such as high-precision laser instrument leveling, engineering machinery leveling, dam monitoring, the launching angle of a satellite missile, the flight attitude of an aircraft and the like, so that the inclination angle sensor has a very wide application prospect. The tilt angle sensor applied in the industry at present can be divided into three types of solid pendulum, liquid pendulum and gas pendulum. Compared with the sum of 'solid pendulum'; the liquid pendulum type tilt angle sensor and the gas pendulum type tilt angle sensor are easily interfered by a plurality of factors, so the gas pendulum type tilt angle sensor has poor performance stability and low actual application rate. Compared with a liquid pendulum tilt sensor, a solid pendulum tilt sensor has the problems of mechanical hysteresis and abrasion.
There is a magnetic liquid sensor having a glass tube filled with a non-magnetic carrier liquid and a magnetic liquid of about half the volume of the container, the glass tube having an excitation coil and a differential induction coil wound around its radially outer periphery. The exciting coil generates a magnetic field to magnetize the magnetic liquid in the tube, when the glass tube is inclined, the magnetic liquid moves under the action of gravity, and the differential induction coil of the outer Zhou Chanrao generates induction current. The current is a function of the sensor tilt angle. Because the inclination angle sensor can only measure the inclination angle in a certain fixed direction, the measurement of the inclination angle in the three-dimensional space can be realized only by at least two inclination angle sensors which are vertically arranged in practical use, and the inclination angle sensor can not realize the synchronous measurement of the inclination angle and the deflection angle; due to the structural limitation of the sensor, the magnetic liquid in the pipe of the tilt sensor moves less and less under the action of gravity along with the increase of the tilt angle, so that the measurement accuracy of the tilt sensor is reduced along with the increase of the tilt angle, and the tilt sensor cannot realize the measurement of +/-180 degrees of full angle; because the sensor needs to generate a magnetic field through the exciting coil, a corresponding exciting power supply needs to be equipped when the tilt angle sensor is used, the use difficulty and the cost of the tilt angle sensor are increased, the conversion from a tilt angle signal to an electric signal is realized through the differential induction coil, the size and the weight of the sensor are increased, and the sensor is inconvenient to use in the existing system.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide the inclination angle sensor which is suitable for +/-180-degree full-angle and multi-azimuth measurement in a three-dimensional space. The sensor solves the problems of fixed and single measuring direction, narrow measuring range and the like of the existing magnetic liquid sensor through the design of the magnetic liquid measuring element, can synchronously measure the inclination angle and the deflection angle in a three-dimensional space, and the measuring range is expanded to +/-180 degrees, thereby obviously improving the applicability and the working efficiency of a measuring system. The sensor solves the problem of uneven change rate of the magnetic induction intensity B along with the change of the inclination angle through the design of the stacked permanent magnets, and obviously improves the measurement precision of the sensor and the stability of the sensor. The sensor solves the problem of a reference object of the deflection direction through the design of the compass on the horizontal base, and increases the normalization of the measured value of the deflection direction angle.
The technical scheme of the invention is as follows:
a magnetic liquid omnibearing horizontal tilt angle sensor comprises a magnetic liquid measuring element, a bracket, a horizontal base and a stacked permanent magnet; the bracket is fixed on the horizontal base through the mounting hole; the magnetic liquid measuring element is arranged on the bracket; the stacked permanent magnet is suspended in the magnetic liquid inside the magnetic liquid measuring element; the horizontal base is fixed on the surface to be detected by a fixing bolt;
the magnetic liquid measuring element comprises a closed spherical shell, a tunneling magneto-resistance (TMR) sensor a, a tunneling magneto-resistance (TMR) sensor b, a tunneling magneto-resistance (TMR) sensor c, a connecting rod, a connecting ring and magnetic liquid; the closed spherical shell is internally provided with magnetic liquid and stacked permanent magnets which account for 40-50% of the volume of the spherical shell, and is connected with the connecting ring through a connecting rod; 4 connecting rods are uniformly distributed on the maximum circumference of the closed spherical shell in the horizontal direction, and one end of each connecting rod is vertically fixed on the spherical shell; the other end of the connecting rod is connected with a connecting ring, and the annular connecting ring is arranged on the outer side of the maximum circumference in the middle of the closed spherical shell; a tunnel magneto-resistance (TMR) sensor b is fixed at the bottommost part of the outer side of the closed spherical shell, and a tunnel magneto-resistance (TMR) sensor a and a tunnel magneto-resistance (TMR) sensor c are respectively positioned at the outer side of the maximum circumference of the closed spherical shell in the horizontal direction and are positioned on the same straight line with the center of the sphere;
the magnetic liquid is kerosene-based Fe 3 O 4 Magnetic liquid of Fe by volume ratio 3 O 4 : kerosene =8:92, preparation; ferroferric oxide is nano-particles, and the diameter range is 2-20 nm;
the stacked permanent magnet is formed by stacking 3-5 cylindrical permanent magnets in the order of the radius from small to large, the thicknesses of the cylindrical permanent magnets are the same, and the cylindrical permanent magnet with the largest diameter is positioned at the top; the cylindrical permanent magnets which are axially magnetized are stacked to form a whole body by virtue of the adsorption force between the cylindrical permanent magnets; the central axes of the permanent magnets are overlapped; the stacked permanent magnet is preferably formed by stacking 5 cylindrical permanent magnets, the thickness of each of the five cylindrical permanent magnets is 2mm, and the radius of each of the five cylindrical permanent magnets is 10mm, 8mm, 6mm, 4mm and 2mm in sequence; the radius of the closed spherical shell is 20mm.
The support is four support legs, and each support leg comprises a semi-annular support column, a support column a, an adjusting column and a support column b; the semi-annular support is used for supporting the connecting ring, and the support b is fixedly arranged in a corresponding support leg mounting hole of the horizontal base; the non-threaded end of the strut a is connected with the semi-annular strut, the threaded end is connected with the adjusting column, and the other end of the adjusting column is connected with the threaded end of the strut b.
The horizontal base of the magnetic liquid omnibearing horizontal tilt angle sensor comprises four support leg mounting holes, four fixing bolt through holes and a compass mounting hole, wherein a compass is mounted in the holes.
The magnetic liquid omnibearing horizontal inclination angle sensor also comprises an A/D (analog/digital) converter and a micro-control processor, wherein each tunneling magneto-resistance (TMR) sensor is connected with one A/D converter, and the three A/D converters are connected with the micro-control processor.
The application method of the magnetic liquid omnibearing horizontal inclination angle sensor comprises the following steps:
(1) Placing magnetic liquid omnibearing horizontal inclination angle sensor to make its lowest tunnel magneto-resistance (TMR) sensor
The axial measurement direction is consistent with the north direction shown by the compass, and at the moment, the magnetic liquid omnibearing horizontal tilt angle sensor is fixed on a surface to be measured, of which the tilt angle and the deflection angle need to be measured, through a fixing bolt;
wherein, the connecting line of the measuring points of the spherical center O and the tunnel magneto-resistance (TMR) sensor c 1-4 is a Y axis, the connecting line of the measuring points of the spherical center O and the tunnel magneto-resistance (TMR) sensor b 1-3 is a Z axis, and the X axis is perpendicular to a plane formed by Y, Z axes;
(2) Adjusting zero of a rotary adjusting column inclination angle sensor: the adjusting columns on the four supporting feet are rotated to ensure that the tunnel magneto-resistors a and c are positioned on the same horizontal line, and at the moment, the tunnel magneto-resistor (TMR) sensors a and c have respective
In the directions of the three magnetic sensitive axes, the output measurement values of the corresponding axes in the three axes are equal; total magnetic induction B measured by tunnel magneto-resistance (TMR) sensor B b Equal to 895.7Gs; zero setting of the magnetic liquid omnibearing horizontal inclination angle sensor is realized;
wherein the three tunnel magnetsThe resistance (TMR) sensors each have
A shaft,
A shaft,
Three tunnel magneto-resistance (TMR) sensors with axes in three mutually perpendicular measuring directions and fixed on spherical shell
The axis is consistent with the direction of the X axis,
the axis is directed towards the centre of the sphere of the spherical shell,
axis perpendicular to
A shaft,
The axis lies in the plane and complies with the right-hand rule;
(3) When the surface to be measured is inclined, standing for 2-3 minutes until the inclination angle sensor is stable;
(4) Collecting output voltage of tunnel magneto-resistance (TMR) sensor, and calculating magnetic induction intensity B a 、B b 、B c The size of (c): the micro control processor STM32 sequentially collects nine paths of differential output voltage signals of three tunnel magneto-resistance (TMR) sensors through an A/D (analog-to-digital) converter ADS 1256; the analog-to-digital converter converts the analog voltage signal into a digital voltage signal and forwards the digital voltage signal to the micro control processor STM32; the micro-control processor STM32 outputs nine digital differential output voltages according to a formula (1) V x ＝K·B x Respectively calculating respective of three tunnel magneto-resistance (TMR) sensors
Magnetic induction component B of three axes of direction x 、B y 、B z Then, the formula (2)
Calculating the magnetic induction B at three positions measured by tunnel magneto-resistance (TMR) sensors a, B and c a 、B b 、B c ；
Wherein, V x 、B x And K are tunnel magneto-resistance (TMR) sensors respectively
Axially outputting voltage, magnetic induction intensity measurement values and sensitivity; b is x 、B y 、B z Three components of magnetic induction B on the spherical shell;
(5) Magnetic induction intensity B is judged to micro-control processor STM32 a 、B b 、B c Substituting the maximum value into the function corresponding to the formula (4) to obtain an inclination angle theta and sending the settlement result to a PC (personal computer) for display through an RS232 serial port line;
wherein θ is an inclination angle; b is a 、B b 、B c Respectively measuring magnetic induction intensity at three positions of a tunnel magneto-resistance (TMR) sensor a, b and c;
(6) After the micro-control processor SIM32 finishes the calculation of the inclination angle theta, the magnetic induction intensity B is calculated a 、B b 、B c Two magnetic induction intensity components B of medium, maximum value y 、B x Substituting the calculated deflection angle beta into a function corresponding to the formula (6), and sending a settlement result to a PC (personal computer) for display through an RS232 serial port line;
wherein β is a deflection angle; b is y 、B x Three magnetic induction densities B a 、B b 、B c Corresponding to the maximum value of
A magnetic induction component;
(7) Both values are obtained and the measurement is finished.
Compared with the prior art, the invention has the beneficial effects that:
1. the design of the magnetic liquid measuring element not only can provide a stable environment which is not influenced by external factors for the magnetic liquid in the magnetic liquid measuring element and the stacked permanent magnet suspended in the magnetic liquid measuring element through the spherical shell structure, but also provides a +/-180-degree full-angle measuring space for a tunnel magneto-resistance (TMR) sensor fixed on the outer side of the spherical shell, so that the magnetic liquid all-dimensional level sensor can simultaneously measure the inclination angle and the deflection angle in a three-dimensional space, the process of measuring the inclination angle in the three-dimensional space is effectively simplified, the range of the inclination angle sensor is expanded to the maximum extent, and all-dimensional measurement in the three-dimensional space is realized.
2. According to the invention, the stacked permanent magnet is used for exciting the magnetic field, firstly, the problem of uneven change rate of the magnetic induction intensity B along with the change of the inclination angle is solved by the design of the stacked permanent magnet, the precision of the sensor is obviously improved, and when the inclination angle slightly changes, the magnetic induction intensity B obviously changes. And secondly, an external excitation source is not needed, the operation process of using the tilt angle sensor is simplified, and the structure of the tilt angle sensor is reduced. Compared with the existing magnetic liquid tilt angle sensor, the magnetic liquid omnibearing horizontal tilt angle sensor has more convenient and faster operation steps.
3. The invention adopts a tunnel magneto-resistance (TMR) sensor to measure the magnitude of magnetic induction intensity B so as to realize the conversion from an angle signal to an electric signal. The tunneling magneto-resistance (TMR) sensor is in a packaging form of LGA (4 mm multiplied by 2.5 mm), and is much smaller in volume compared with a differential induction coil. The tunnel magneto-resistance (TMR) sensor has high sensitivity, a 5V direct-current power supply is adopted to supply power to the tunnel magneto-resistance (TMR) sensor, and the sensitivity K of the tunnel magneto-resistance (TMR) sensor is 5mV/Gs. The tunnel magneto-resistance (TMR) sensor can accurately acquire signals, improve the sensitivity precision of the magnetic liquid all-dimensional level sensor and simplify the whole structure of the sensor.
Drawings
FIG. 1 is a schematic diagram of the overall structure of the magnetic liquid omni-directional horizontal tilt sensor of the present invention;
FIG. 2 is a schematic diagram of a magnetic liquid measuring cell of the magnetic liquid omni-directional horizontal tilt sensor of the present invention;
FIG. 3 is a schematic diagram of a vertical cross-sectional structure of a magnetic liquid measuring cell of the magnetic liquid omni-directional horizontal tilt sensor of the present invention;
FIG. 4 is a schematic structural diagram of one embodiment of a stacked permanent magnet of the magnetic liquid omni-directional horizontal tilt angle sensor of the present invention;
FIG. 5 is a schematic diagram of the coordinate system of the magnetic liquid omnibearing horizontal tilt angle sensor according to the present invention;
FIG. 6 is a schematic structural diagram of a leg of the magnetic liquid omni-directional horizontal tilt sensor of the present invention;
FIG. 7 is a schematic view of a horizontal base structure of the magnetic liquid omni-directional horizontal tilt sensor of the present invention;
FIG. 8 is a graph showing the functional relationship between the magnetic induction B and the tilt angle θ in a quarter of the circumference of the magnetic liquid measuring element of the magnetic liquid omni-directional horizontal tilt sensor according to the present invention;
FIG. 9 is a schematic diagram of the magnetic liquid omni-directional horizontal tilt angle sensor of the present invention for measuring the deflection angle;
FIG. 10 is a schematic diagram of the resolving deflection angle of the magnetic liquid omni-directional horizontal tilt angle sensor according to the present invention;
in the figure, 1, a magnetic liquid measuring element, 2, a bracket, 3, a horizontal base, 4, a stacked permanent magnet, 1-1, a closed spherical shell, 1-2, a tunneling magneto-resistance (TMR) sensor a, 1-3, a tunneling magneto-resistance (TMR) sensor b, 1-4, a tunneling magneto-resistance (TMR) sensor c, 1-5, a connecting rod, 1-6, a connecting ring, 1-7, magnetic liquid, 4-1, a cylindrical permanent magnet a, 4-2, a cylindrical permanent magnet b, 4-3, a cylindrical permanent magnet c, 4-4, a cylindrical permanent magnet d, 4-5, a cylindrical permanent magnet e, 2-1, a semi-annular support, 2-2, an adjusting column, 2-4, a support column b, 3-1, a support leg mounting hole, 3-2, a support leg b mounting hole, 3-3, a compass mounting hole, 3-4, a support leg c mounting hole, 3-5, a support leg d mounting hole, 3-6, a fixing bolt through hole a, 3-7, a fixing bolt b, 3-8, a fixing bolt through hole and a fixing bolt through hole.
Detailed Description
The invention is described in further detail below with reference to examples and figures:
as shown in fig. 1, the overall structure of the magnetic liquid omni-directional horizontal tilt sensor of the present invention includes a magnetic liquid measuring element 1, a support 2, a horizontal base 3 and a stacked permanent magnet 4; the bracket 2 is fixed on the horizontal base through a mounting hole; the magnetic liquid measuring element 1 is arranged on the bracket 2; the stacked permanent magnet 4 is suspended in the magnetic liquid inside the magnetic liquid measuring element 1; the horizontal base 3 is fixed on the surface to be detected by a fixing bolt;
as shown in fig. 2, the magnetic liquid measuring element 1 includes a closed spherical shell 1-1, a tunneling magneto-resistance (TMR) sensor a 1-2, a tunneling magneto-resistance (TMR) sensor b 1-3, a tunneling magneto-resistance (TMR) sensor c 1-4, a connection rod 1-5, a connection ring 1-6, and a magnetic liquid 1-7; a closed spherical shell with the outer diameter of 40mm is internally provided with magnetic liquid 1-7 and a stacked permanent magnet 4 which account for 40-50% of the volume of the spherical shell, and is connected with a connecting ring 1-6 through a connecting rod 1-5; 4 connecting rods 1-5 are uniformly distributed on the maximum circumference of the closed spherical shell 1-1 in the horizontal direction, and one end of each connecting rod 1-5 is vertically fixed on the spherical shell; the other end of the connecting rod 1-5 is connected with the connecting ring 1-6, and the annular connecting ring 1-6 is arranged on the outer side of the maximum circumference in the middle of the closed spherical shell 1-1; a tunnel magneto-resistance (TMR) sensor b 1-3 is fixed at the bottommost part of the outer side of the closed spherical shell 1-1, a tunnel magneto-resistance (TMR) sensor a 1-2 and a tunnel magneto-resistance (TMR) sensor c 1-4 are respectively positioned at the outer side of the maximum circumference of the closed spherical shell 1-1 in the horizontal direction, and the tunnel magneto-resistance (TMR) sensor a 1-2 and the tunnel magneto-resistance (TMR) sensor c 1-4 are positioned on the same straight line with the center of a sphere;
as shown in FIG. 3, the magnetic liquid of the magnetic liquid omnibearing horizontal inclination angle sensor of the present inventionThe vertical section structure of the measuring element comprises a closed spherical shell 1-1, a tunneling magneto-resistance (TMR) sensor a 1-2, a tunneling magneto-resistance (TMR) sensor b 1-3, a tunneling magneto-resistance (TMR) sensor c 1-4, a stacked permanent magnet 4 and magnetic liquid 1-7; the magnetic liquid 1-7 is a novel functional material, in particular to kerosene base Fe 3 O 4 Magnetic liquid of Fe by volume ratio 3 O 4 : kerosene =8:92 preparation, density 1.13g/cm 3 The viscosity is 3.25 mPas, the saturation magnetization is 381.5Gs, the ferroferric oxide is nano-particles, the diameter range is 2-20 nm, and the average value is 10nm. The kerosene base is Fe 3 O 4 The magnetic liquid has the characteristic of being capable of suspending magnetic substances with density higher than that of the magnetic liquid, and can be used for providing a suspension environment which can be static relative to the gravity direction for the stacked permanent magnet; the stack type permanent magnet 4 provides a measurable static magnetic field relative to the gravity direction for a tunnel magneto-resistance (TMR) sensor by utilizing a magnetic field excited by the stack type permanent magnet and a suspension environment which is provided by the magnetic liquid and is static relative to the gravity direction.
The stacked permanent magnet 4 is formed by stacking 3-5 cylindrical permanent magnets with the same thickness in a sequence from small radius to large radius, wherein the thickness of each cylindrical permanent magnet is in the range of 0.05-0.14 times of the radius of the closed spherical shell, the total thickness of the stacked permanent magnets is in the range of 0.25-0.7 times of the radius of the closed spherical shell, and the radius of each cylindrical permanent magnet is in the range of 0.05-0.6 times of the radius of the closed spherical shell; as shown in fig. 4, in an embodiment of the stacked permanent magnet of the omnibearing horizontal inclination angle sensor for magnetic liquid according to the present invention, the radius of the closed spherical shell is 20mm, and the stacked permanent magnet includes a cylindrical permanent magnet a 4-1, a cylindrical permanent magnet b 4-2, a cylindrical permanent magnet c 4-3, a cylindrical permanent magnet d 4-4, and a cylindrical permanent magnet e 4-5; the thickness of each of the five cylindrical permanent magnets is 2mm, and the radiuses of the five cylindrical permanent magnets are 10mm, 8mm, 6mm, 4mm and 2mm in sequence; five cylindrical permanent magnets which are axially magnetized are stacked to form a whole by means of the adsorption force among the five cylindrical permanent magnets; the central axes of the five permanent magnets are overlapped. In the above-mentioned embodiment the lowest point of the permanent magnet is 3mm from the lowest point of the spherical shell. But in general embodiments the height of the permanent magnet in the magnetic liquid is arbitrary.
The magnetic liquid omnibearing horizontal inclination angle sensor also comprises an A/D (analog to digital) converter and a micro-control processor, the three tunneling magneto-resistance (TMR) sensors are the same in composition, each tunneling magneto-resistance (TMR) sensor is connected with one A/D (analog to digital) converter, and the three A/D converters are connected with the micro-control processor.
Analog electric signals output by the three tunnel magneto resistors are sequentially converted into digital electric signals by an analog-to-digital (ADS) 1256, the digital electric signals are transmitted to a micro-control processor STM32 for calculation and processing, and the micro-control processor transmits settlement results to a Personal Computer (PC) for display through an RS232 serial port line.
The tunneling magneto-resistive (TMR) sensor is a commercially known electronic device having
When the magnetic force line of the magnetic field and the magnetic sensitive shaft are in the same direction, the linear magnetic sensors in the directions of the three mutually perpendicular magnetic sensitive shafts have the following effects according to the tunnel magnetoresistance effect:
V x ＝K·B x (1)
wherein, V x 、B x And K are tunnel magneto-resistance (TMR) sensors respectively
Axially outputting voltage, magnetic induction intensity measurement values and sensitivity; the magnetic induction B on the spherical shell can be divided into three components B which are perpendicular to each other x 、B y 、B z Comprising the following steps:
from this relationship, a tunneling magneto-resistance (TMR) sensor can measure the magnetic induction B on the spherical shell. In the embodiment, the sensitivity K of the tunneling magneto-resistance is 5mV/Gs.
To better illustrate the measurement directions of the respective magnetic sensitive axes of the three tunneling magneto-resistance (TMR) sensors on the spherical shell, a spatial rectangular coordinate as shown in FIG. 5 is establishedThe system is that the sphere center O of the magnetic liquid measuring element 1 is taken as the origin of a rectangular space coordinate system, the connecting line of the sphere center O and the measuring point of a tunnel magneto-resistance (TMR) sensor c 1-4 is the Y axis, the connecting line of the sphere center O and the measuring point of a tunnel magneto-resistance (TMR) sensor b 1-3 is the Z axis, and the X axis is perpendicular to the plane formed by Y, Z; measurement direction of initial state tunneling magneto-resistance (TMR) sensor b 1-3
The direction of the axis is consistent with that of the established coordinate system; the magnetic liquid measuring element 1 rotates clockwise 90 degrees around the X axis as the center, and the measuring direction of a tunneling magneto-resistance (TMR) sensor c 1-4 is measured at the moment
The axis is consistent with the measuring direction of a tunnel magneto-resistance (TMR) sensor b 1-3; the magnetic liquid measuring element 1 rotates 90 DEG counterclockwise around the X-axis as a center, and the measuring direction of the tunneling magneto-resistance (TMR) sensor a 1-2 is measured at this time
The axis coincides with the measurement direction of the tunneling magneto-resistance (TMR) sensor b 1-3. The tunneling magneto-resistance (TMR) sensor has
A shaft,
A shaft,
Three tunnel magneto-resistance (TMR) sensors with axes in three mutually perpendicular measuring directions and fixed on spherical shell
The axis is consistent with the direction of the X axis,
the axis is directed towards the centre of the sphere of the spherical shell,
axis perpendicular to
A shaft,
The axis lies in the plane and complies with the right-hand rule;
the support 2 is provided with four support legs, and the structure of each support leg is shown in figure 6 and comprises a semi-annular support column 2-1, a support column a 2-2, an adjusting column 2-3 and a support column b 2-4; the unthreaded end of the strut a 2-2 is connected with the semi-annular strut 2-1, the threaded end is connected with the adjusting column 2-3, and the other end of the adjusting column 2-3 is connected with the threaded end of the strut b 2-4. When the adjusting column 2-3 is rotated clockwise, the support column a 2-2 moves upwards, so that the relative position of the magnetic liquid measuring element and the horizontal base is adjusted to achieve the purpose of zero adjustment of the tilt angle sensor. One end of the pillar b2-4 is connected with the horizontal base 3 and is fixedly arranged in the supporting leg mounting through hole of the horizontal base. One end of the semi-annular strut 2-1 is connected with the connecting ring 1-6 to play a role of supporting the magnetic liquid measuring element;
as shown in FIG. 7, the structural schematic diagram of the horizontal base of the magnetic liquid omnibearing horizontal tilt angle sensor comprises four supporting foot mounting holes, a supporting foot a 3-1, a supporting foot b 3-2, a supporting foot c 3-4, a supporting foot d 3-5, four fixing bolt through holes, a through hole a 3-6, a through hole b 3-7, a through hole c 3-8, a through hole d 3-9 and a compass mounting hole 3-3, wherein a compass is mounted in the mounting hole 3-3. Mounting support feet into corresponding mounting holes, fixing the horizontal base of the magnetic liquid omnibearing horizontal tilt angle sensor to a surface to be measured through a fixing bolt through hole, and ensuring that the north direction shown by a compass and a tunnel magneto-resistance (TMR) sensor b 1-2 are ensured during fixing
The axial measurement directions are consistent.
As shown in fig. 8, the magnitude of the magnetic induction B within a quarter of the outer side of the spherical shell (as shown by the dotted line in fig. 3) is calculated by using the lowest point on the spherical shell as the origin at an interval of 0.4 degrees by using a finite element method; when theta =0, the magnetic induction intensity B is maximum, and the maximum value is 895.7Gs; when theta =90 degrees, the magnetic induction intensity B is minimum, and the minimum value is 143.3Gs; determining a functional relation between the magnetic induction intensity B and the inclination angle theta by adopting a polynomial regression analysis method as follows:
B＝f(θ)＝877.927-14.713θ+0.075θ 2 (90 degrees > theta > 0 degrees) and (3) a correlation coefficient R-Square =0.99529, and data have high correlation degree; from this formula the tilt angle theta can be calculated.
The device of the invention can measure the inclination angle theta and the deflection angle beta in the three-dimensional space. The measurement calculation process for the two angles is described below.
The invention measures the angle theta of inclination (angle relative to Z axis in space rectangular coordinate system O) and calculates the process according to the magnetic induction intensity B measured by tunnel magneto-resistance (TMR) sensors a 1-2, B1-3 and c 1-4 at three positions a 、B b 、B c And formula (3) according to three magnetic induction B a 、B b 、B c The magnitude relation determines a calculation function, and the maximum value is substituted into the corresponding formula (4) to calculate the inclination angle theta.
The invention measures the deflection angle beta (relative to the angle of X axis in the space rectangular coordinate system O, namely the angle in the initial state
) In the calculation process, as shown in the schematic diagram of fig. 9 for measuring the deflection angle β, three magnetic induction intensities B are used to calculate the inclination angle θ a 、B b 、B c By rotating the measurement point of the maximum value by 360 ° about the Z axis, the possible positions on the spherical shell are determined, which form a circle with its center on the Z axis, as shown in fig. 9
Shown as a straight line
Perpendicular to the circular plane and perpendicular to the foot
Point; measurement point O 1 、O 3 、O 4 Is a circle
The intersection point, O, of two axial planes XZ and YZ in the rectangular space coordinate system 2 Is O 1 And O 3 At any point in between. Of a tunneling magneto-resistance (TMR) sensor at a deflection angle beta different from the measurement point
The triaxial measurement direction changes; since the stacked permanent magnets 3-5 generate a symmetrical magnetic field,
axis and straight line
The included angle between the two is the inclined angle theta and is kept constant, so the circle
The magnetic induction intensity B corresponding to any point is equal in size and can be decomposed into two constant components B xy 、B z As to O in the figure 1 The decomposition of the magnetic induction B at the measurement point is shown.
As shown in FIG. 10, in
In-plane to constant component B xy Synthesis and decomposition ofAnd deflection angle β are specified; wherein B is 1 、B 2 、B 3 、B 4 Respectively, in a circle
To O 1 、O 2 、O 3 、O 4 Constant component B of different measuring point positions xy (ii) a Constant component B xy In that
The size in the plane is unchanged, but the direction changes along with the deflection angle beta; the initial state defines a constant component B xy And
with axes in the same direction and a constant component B of deflection angle beta xy And
the included angle of the axes; by applying a constant component B xy At O 2 The orthogonal decomposition is performed on the B2 at the measurement point, and it is known that the deflection angle β at this time is:
wherein | B y I and I B x I is the magnetic induction intensity B on the spherical shell
Absolute value of the on-axis component. The formula (5) is generalized to be applicable to a +/-180-degree full angle.
The application method of the magnetic liquid omnibearing horizontal inclination angle sensor comprises the following steps:
(1) Placing magnetic liquid omnibearing horizontal tilt angle sensor to make tunnel magneto-resistance (TMR) sensor at lowest part
The axial measurement direction is consistent with the north direction shown by the compass, and at the moment, the magnetic liquid omnibearing horizontal tilt angle sensor is fixed on a surface to be measured, of which the tilt angle and the deflection angle need to be measured, through a fixing bolt;
wherein, the connecting line of the measuring points of the spherical center O and the tunnel magneto-resistance (TMR) sensor c 1-4 is a Y axis, the connecting line of the measuring points of the spherical center O and the tunnel magneto-resistance (TMR) sensor b 1-3 is a Z axis, and the X axis is perpendicular to a plane formed by Y, Z axes;
(2) Adjusting zero of the inclination angle sensor of the rotary adjusting column: the adjusting columns on the four supporting feet are rotated to enable the tunnel magneto-resistances a and c to be in the same horizontal line, and at the moment, the tunnel magneto-resistance (TMR) sensors a and c respectively
In the directions of the three magnetic sensitive axes, the output measurement values of the corresponding axes in the three axes are equal; total magnetic induction B measured by tunnel magneto-resistance (TMR) sensor B b Equal to 895.7Gs; zero setting of the magnetic liquid omnibearing horizontal tilt angle sensor is realized;
wherein the three tunneling magneto-resistance (TMR) sensors each have
A shaft,
A shaft,
Three tunnel magneto-resistance (TMR) sensors with axes in three mutually perpendicular measuring directions and fixed on spherical shell
The axis is consistent with the direction of the X axis,
the axis is directed towards the centre of the sphere of the spherical shell,
axis perpendicular to
A shaft,
The axis lies in the plane and complies with the right-hand rule;
(3) When the surface to be measured inclines, standing for 2-3 minutes until the inclination angle sensor is stable;
(4) Collecting output voltage of tunnel magneto-resistance (TMR) sensor, and calculating magnetic induction intensity B a 、B b 、B c The size of (2): the micro control processor STM32 sequentially collects nine paths of differential output voltage signals of three tunnel magneto-resistance (TMR) sensors through an A/D (analog-to-digital) converter ADS 1256; the analog-to-digital converter converts the analog voltage signal into a digital voltage signal and forwards the digital voltage signal to the micro control processor STM32; the micro-control processor STM32 outputs nine digital differential output voltages according to a formula (1) V x ＝K·B x Respectively calculating respective of three tunnel magneto-resistance (TMR) sensors
Magnetic induction component B of three axes of direction x 、B y 、B z Then, the formula (2)
Calculating the magnetic induction intensity B at three positions measured by tunnel magneto-resistance (TMR) sensors a, B and c a 、B b 、B c ；
Wherein, V x 、B x And K are tunnel magneto-resistance (TMR) sensors respectively
Axially outputting voltage, magnetic induction intensity measurement values and sensitivity; b is x 、B y 、B z Three components of magnetic induction B on the spherical shell;
(5) Magnetic induction intensity B judged by micro-control processor STM32 a 、B b 、B c Substituting the maximum value into the function corresponding to the formula (4) to obtain an inclination angle theta and sending the settlement result to a PC (personal computer) for display through an RS232 serial port line;
wherein θ is an inclination angle; b is a 、B b 、B c Respectively measuring magnetic induction intensity at three positions of a tunnel magneto-resistance (TMR) sensor a, b and c;
(6) After the micro-control processor SIM32 finishes the calculation of the inclination angle theta, the magnetic induction intensity B is calculated a 、B b 、B c Two magnetic induction intensity components B of medium, maximum value y 、B x Substituting the calculated deflection angle beta into a function corresponding to the formula (6), and sending a settlement result to a PC (personal computer) for display through an RS232 serial port line;
wherein β is a deflection angle; b is y 、B x Three magnetic induction densities B a 、B b 、B c Corresponding to the maximum value of
A magnetic induction component;
(7) Both values are obtained and the measurement is finished.
It should be emphasized that the described embodiments of the present invention are illustrative rather than restrictive, and thus the present invention includes embodiments that are not limited to the embodiments described in the detailed description, and that other embodiments derived from the technical solutions of the present invention by those skilled in the art are also within the scope of the claims of the present application.
Nothing in this specification is said to apply to the prior art.
Claims (4)
1. An omnibearing horizontal inclination sensor of magnetic liquid is characterized in that the sensor comprises a magnetic liquid measuring element, a bracket, a horizontal base and a stacked permanent magnet; the bracket is fixed on the horizontal base through the mounting hole; the magnetic liquid measuring element is arranged on the bracket; the stacked permanent magnet is suspended in the magnetic liquid inside the magnetic liquid measuring element; the horizontal base is fixed on the surface to be detected by a fixing bolt;
the magnetic liquid measuring element comprises a closed spherical shell, a tunneling magneto-resistance (TMR) sensor a, a tunneling magneto-resistance (TMR) sensor b, a tunneling magneto-resistance (TMR) sensor c, a connecting rod, a connecting ring and magnetic liquid; the closed spherical shell is internally provided with magnetic liquid and stacked permanent magnets which account for 40-50% of the volume of the spherical shell, and is connected with the connecting ring through a connecting rod; 4 connecting rods are uniformly distributed on the maximum circumference of the closed spherical shell in the horizontal direction, and one end of each connecting rod is vertically fixed on the spherical shell; the other end of the connecting rod is connected with a connecting ring, and the annular connecting ring is arranged on the outer side of the maximum circumference in the middle of the closed spherical shell; a tunnel magneto-resistance (TMR) sensor b is fixed at the bottommost part of the outer side of the closed spherical shell, and a tunnel magneto-resistance (TMR) sensor a and a tunnel magneto-resistance (TMR) sensor c are respectively positioned at the outer sides of the maximum circumference of the closed spherical shell in the horizontal direction and are positioned on the same straight line with the center of the sphere;
the stacked permanent magnet is formed by stacking 3-5 cylindrical permanent magnets in the order of the radius from small to large, the thicknesses of the cylindrical permanent magnets are the same, and the cylindrical permanent magnet with the largest diameter is positioned at the top; the cylindrical permanent magnets magnetized in the axial direction are stacked to form a whole by means of the adsorption force between the cylindrical permanent magnets; the central axes of the permanent magnets are overlapped;
the support is four support legs, and each support leg comprises a semi-annular support column, a support column a, an adjusting column and a support column b; the semi-annular support is used for supporting the connecting ring, and the support b is fixedly arranged in a corresponding support leg mounting hole of the horizontal base; the non-threaded end of the strut a is connected with the semi-annular strut, the threaded end of the strut a is connected with the adjusting column, and the other end of the adjusting column is connected with the threaded end of the strut b;
the horizontal base of the magnetic liquid omnibearing horizontal tilt angle sensor comprises four support leg mounting holes, four fixing bolt through holes and a compass mounting hole, wherein a compass is mounted in the mounting hole;
the magnetic liquid omnibearing horizontal inclination angle sensor also comprises an A/D (analog/digital) converter and a micro-control processor, wherein each tunneling magneto-resistance (TMR) sensor is connected with one A/D converter, and the three A/D converters are connected with the micro-control processor.
2. The omnibearing horizontal inclination angle sensor of magnetic liquid according to claim 1, characterized in that said stackable permanent magnet is composed of 5 cylindrical permanent magnets stacked together, the five cylindrical permanent magnets are 2mm thick and have radii of 10mm, 8mm, 6mm, 4mm, 2mm in this order; the radius of the closed spherical shell is 20mm.
3. The omni-directional horizontal tilt sensor of magnetic fluid of claim 1 wherein said magnetic fluid is kerosene based Fe 3 O 4 Magnetic liquid of Fe by volume ratio 3 O 4 : kerosene =8:92, preparation; the ferroferric oxide is nano-particles, and the diameter range is 2-20 nm.
4. The method of claim 1, wherein the magnetic liquid omni-directional horizontal tilt sensor comprises the steps of:
(1) Placing magnetic liquid omnibearing horizontal tilt angle sensor to make tunnel magneto-resistance (TMR) sensor at lowest part
The axial measurement direction is consistent with the north direction shown by the compass, and at the moment, the magnetic liquid omnibearing horizontal tilt angle sensor is fixed on a surface to be measured, of which the tilt angle and the deflection angle need to be measured, through a fixing bolt;
wherein, the connecting line of the measuring points of the spherical center O and the tunnel magneto-resistance (TMR) sensor c 1-4 is a Y axis, the connecting line of the measuring points of the spherical center O and the tunnel magneto-resistance (TMR) sensor b 1-3 is a Z axis, and the X axis is perpendicular to a plane formed by Y, Z axes;
(2) Adjusting zero of a rotary adjusting column inclination angle sensor: the adjusting columns on the four supporting feet are rotated to enable the tunnel magneto-resistances a and c to be in the same horizontal line, and at the moment, the tunnel magneto-resistance (TMR) sensors a and c respectively
In the directions of the three magnetic sensitive axes, the output measurement values of the corresponding axes in the three axes are equal; total magnetic induction B measured by tunneling magneto-resistance (TMR) sensor B b Equal to 895.7Gs; zero setting of the magnetic liquid omnibearing horizontal inclination angle sensor is realized;
wherein each of the three tunneling magneto-resistance (TMR) sensors has
A shaft,
A shaft,
Three tunnel magneto-resistance (TMR) sensors with axes in three mutually perpendicular measuring directions and fixed on spherical shell
The axis is consistent with the direction of the X axis,
the axis is directed towards the centre of the sphere of the spherical shell,
axis perpendicular to
A shaft,
The axis lies in the plane and complies with the right-hand rule;
(3) When the surface to be measured is inclined, standing for 2-3 minutes until the inclination angle sensor is stable;
(4) Collecting output voltage of tunnel magneto-resistance (TMR) sensor, and calculating magnetic induction intensity B a 、B b 、B c The size of (2): the micro control processor STM32 sequentially collects nine differential output voltage signals of three tunneling magneto-resistance (TMR) sensors through an A/D (analog-to-digital) converter ADS 1256; the analog-to-digital converter converts the analog voltage signal into a digital voltage signal and forwards the digital voltage signal to the micro control processor STM32; the micro-control processor STM32 outputs nine digital differential output voltages according to a formula (1) V x ＝K·B x Respectively calculating respective of three tunnel magneto-resistance (TMR) sensors
Magnetic induction component B of three axes of direction x 、B y 、B z Then, the formula (2)
Calculating the magnetic induction intensity B at three positions measured by tunnel magneto-resistance (TMR) sensors a, B and c a 、B b 、B c ；
Wherein, V x 、B x And K are tunnel magneto-resistance (TMR) sensors respectively
Axially outputting voltage, magnetic induction intensity measurement values and sensitivity; b is x 、B y 、B z Three components of magnetic induction B on the spherical shell;
(5) Magnetic induction intensity B judged by micro-control processor STM32 a 、B b 、B c Substituting the maximum value into the function corresponding to the formula (4) to obtain an inclination angle theta and sending the settlement result to a PC (personal computer) for display through an RS232 serial port line;
wherein θ is an inclination angle; b is a 、B b 、B c Respectively measuring magnetic induction intensity values of a tunnel magneto-resistance (TMR) sensor at a position a, a position b and a position c;
(6) After the micro-control processor SIM32 finishes the calculation of the inclination angle theta, the magnetic induction intensity B is calculated a 、B b 、B c Two magnetic induction intensity components B of medium, maximum value y 、B x Substituting the calculated deflection angle beta into a function corresponding to the formula (6), and sending a settlement result to a PC (personal computer) for display through an RS232 serial port line;
wherein β is a deflection angle; b is y 、B x Three magnetic induction densities B a 、B b 、B c Corresponding to the maximum value of
A magnetic induction component;
(7) Both values are obtained and the measurement is ended.
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| JP7258348B2 (en) * | 2019-07-27 | 2023-04-17 | 株式会社日本アレフ | fall detection sensor |
| CN113818866B (en) * | 2021-11-24 | 2022-02-08 | 枣庄高新区立正安装工程有限公司 | All-round inclinometer |
| CN114935329A (en) * | 2022-05-18 | 2022-08-23 | 清华大学 | Magnetic liquid horizontal inclination angle sensor |
| CN114952418B (en) * | 2022-08-01 | 2023-01-13 | 扬州市翰玛机电有限公司 | External base level of lathe indicates ware |
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