WO2007099599A1

WO2007099599A1 - Magnetic gyroscope

Info

Publication number: WO2007099599A1
Application number: PCT/JP2006/303745
Authority: WO
Inventors: Yoshinobu Honkura; Katsuhiko Tsuchida; Eiji Kako
Original assignee: Aichi Micro Intelligent Corporation
Priority date: 2006-02-28
Filing date: 2006-02-28
Publication date: 2007-09-07
Also published as: JPWO2007099599A1

Abstract

A magnetic gyroscope (1) comprises a three-axis magnetic sensor (2) for detecting geomagnetism as a magnetic vector in a three-axis orthogonal coordinate system fixed to a measured object, a memory (3) for storing data on the magnetic vector chronologically detected by the three-axis magnetic sensor (2) when the measured object moves around any rotation axis running through the origin of the three-axis orthogonal coordinate system, a rotation axis calculator (4) for calculating the rotation axis according to the magnetic vector data at three or more different points of time stored in the memory (3), and a rotation angle calculator (5) for calculating the rotation angle of the measured object around the rotation axis according to the magnetic vector data.

Description

Specification

Magnetic gyro

Technical field

[0001] The present invention relates to a magnetic gyro that uses geomagnetism to measure a rotation angle based on an arbitrary posture or to measure a rotation angular velocity.

Background art

[0002] In recent years, for example, when a portable electronic device such as a mobile phone or a PDA is tilted or swung, the rotation angle in the pitch, shoot, and roll directions (apparatus posture) and the rotation angular velocity are detected, and these are detected by the above mobile phone. Techniques have been developed for use as input signals to electronic devices.

In addition, a technology has been developed to detect camera rotation angles and rotation angular velocities and use them as correction signals to prevent camera shake in photographs (photographed images)!

In these technologies, a gyro is used as a means for detecting the rotation angle and rotation angular velocity of the device.

[0003] The gyro includes, for example, a directional gyro that measures postures and azimuths (that is, rotation angles) of various devices, vehicles, airplanes, and the like, and a rate gyro that measures a rotation angular velocity that is a change rate of the rotation angle. There is. There is also a means for calculating the rotation angle by integrating the rate gyro output signal.

[0004] As the directional gyro described above, a mechanical rotor that rotates about an axis is supported by a gimbal, and the rotation angle (posture and azimuth angle) of the measured object is measured using the inertia force of the rotor. (Patent Document 1).

Moreover, as the rate gyro, a vibration gyro of a type that detects a signal corresponding to Coriolis acting on a vibrator is often used (Patent Document 2).

[0005] However, all of these conventional gyros utilize the kinematic principle. Therefore, there is a risk of reacting to mechanical vibrations or impacts other than the rotational motion that is the object of measurement. As a result, there is a problem that noise is superimposed on the output signal and accurate measurement may be difficult.

[0006] The directional gyro described in Patent Document 1 requires a complicated mechanism. Therefore, it is difficult to reduce the size if the cost is low. In addition, a lot of electric power is required to rotate the rotor. Therefore, it will be limited to special uses, such as an aircraft.

Further, the rate gyro described in Patent Document 2 (vibration gyro) also requires a vibration mechanism, so that it is difficult to reduce the size.

Therefore, it is difficult to incorporate these gyros into, for example, portable electronic devices that are becoming smaller and higher in density.

[0007] Patent Document 1: US Patent No. 3143892

Patent Document 2: JP-A-7-139951

Disclosure of the invention

Problems to be solved by the invention

[0008] The present invention has been made in view of the conventional problems that are striking, and an object of the present invention is to provide a magnetic gyro that is excellent in measurement accuracy and that can be easily miniaturized.

Means for solving the problem

[0009] The present invention provides a three-axis magnetic sensor that detects geomagnetism as a magnetic vector in a three-axis orthogonal coordinate system fixed to a measurement object;

Memory that accumulates data of the magnetic vector detected in time series by the 3-axis magnetic sensor when the measured object moves around an arbitrary rotation axis passing through the origin of the 3-axis orthogonal coordinate system When,

Rotation axis calculation means for calculating the rotation axis based on the magnetic vector data at three or more different points of time accumulated in the memory;

There is provided a magnetic gyro comprising rotation angle calculation means for calculating a rotation angle of the measured object around the rotation axis based on data of the magnetic vector.

Next, the function and effect of the present invention will be described.

The magnetic gyro has the three-axis magnetic sensor, the memory, the rotation axis calculation means, and the rotation angle calculation means. Based on the geomagnetism detected by the three-axis magnetic sensor, the change in the posture of the measured object is detected. Under normal circumstances, geomagnetism basically has a certain direction and size relative to the ground. Therefore, when the posture of the object to be measured, that is, when the posture of the 3-axis Cartesian coordinate system changes, the 3-axis The magnetic vector in the orthogonal coordinate system will change. By detecting this changing magnetic vector, it is possible to accurately measure changes in the posture of the measured object.

[0011] The change in the posture of the measured object can be specified by an arbitrary rotation angle around an arbitrary rotation axis.

Therefore, in the magnetic gyro as described above, the rotation axis is calculated by the rotation axis calculation means. The memory stores the magnetic vector data at three or more different points necessary to calculate the rotation axis. Further, the rotation angle calculation means calculates the rotation angle of the measured object around the rotation axis based on the magnetic vector data.

As described above, since the rotation axis and the rotation angle around the rotation axis can be obtained, the change in the posture of the measurement object can be measured.

[0012] Further, unlike the conventional mechanical gyro using the kinematic principle, the magnetic gyro can measure a change in posture of the measurement object based on the geomagnetism. Therefore, even if mechanical vibrations or impacts other than the rotational motion to be measured are applied, accurate measurement without reacting to these can be ensured.

[0013] In addition, since the magnetic gyro uses a three-axis magnetic sensor, it does not require a complicated mechanism or a lot of electric power unlike a mechanical type. Therefore, downsizing and low cost can be easily achieved. As a result, it can be easily incorporated into, for example, portable electronic devices whose size and density are increasing.

[0014] As described above, according to the present invention, it is possible to provide a magnetic gyro which is excellent in measurement accuracy and can be easily miniaturized.

Brief Description of Drawings

FIG. 1 is a conceptual diagram of a magnetic gyroscope in an embodiment.

FIG. 2 is an explanatory diagram of a three-axis orthogonal coordinate system, a rotation axis, a magnetic vector, and the like in the embodiment.

FIG. 3 is an auxiliary explanatory diagram of a method for calculating center coordinates in the embodiment.

FIG. 4 is an auxiliary explanatory diagram of a method for calculating a rotation angle in the embodiment.

FIG. 5 is a perspective view of a three-axis magnetic sensor in the example.

FIG. 6 is a plan view of a magneto 'impedance' sensor element in an example. FIG. 7 is a schematic cross-sectional view taken along line A—A in FIG.

BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention, the magnetic gyro can be mounted on various measured objects such as mobile electronic devices such as mobile phones and PDAs, cameras, vehicles, robots, aircrafts, ships, and the like.

The magnetic vector is a vector parallel to the geomagnetism starting from the origin in the three-axis orthogonal coordinate system, and its magnitude is constant.

[0017] Further, the magnetic gyro is configured to calculate a rotation angle of the measured object between two different time points calculated by the rotation angle calculating means and a difference between the sampling times of the magnetic vector data at the two time points. On the basis of this, it is preferable to have an angular velocity calculating means for calculating the rotational angular velocity of the object to be measured around the rotation axis.

In this case, it is possible to obtain a magnetic jar that can easily detect the rotational angular velocity of the object to be measured. Therefore, it is possible to detect the posture change speed that is based on only the posture change amount of the measured object.

[0018] Further, it is preferable that the interval at which the magnetic vector data is collected is constant.

In this case, the calculation in the rotation axis calculation means and the rotation angle calculation means can be performed easily and accurately, and the posture change can be accurately measured.

[0019] In addition, the rotation axis calculation means calculates two difference vectors that are differences between two magnetic vectors among the magnetic vectors at three or more different time points, and calculates an outer product of these two difference vectors. Accordingly, it is preferable to calculate a rotation axis vector in the same direction as the rotation axis. In this case, the rotation axis can be calculated easily and accurately.

[0020] Further, the rotation angle calculation means includes a data plane determined by coordinate points of the magnetic vector at three or more different time points in the three-axis orthogonal coordinate system, and the rotation axis calculated by the rotation axis calculation means. Rotation center coordinate calculation means for calculating the center coordinates of the trajectory circle passing through the coordinate points of the above magnetic vector at three or more different time points by calculating the intersection of the above and the center calculated by the rotation center coordinate calculation means Calculate the radius to calculate the radius of the locus circle by calculating the distance between the coordinates and the coordinate point of the magnetic vector. Preferably, the rotation angle is calculated based on the radius of the locus circle calculated by the radius calculation means and the coordinate points of the magnetic vector at two different time points.

In this case, the rotation angle can be calculated easily and accurately.

[0021] The rotation center coordinate calculation means may calculate the center coordinate of the trajectory circle by taking an inner product of the rotation axis vector calculated by the rotation axis calculation means and the magnetic vector. preferable.

In this case, the center coordinates can be calculated easily and accurately.

[0022] The radius calculation means calculates the radius of the trajectory circle by calculating a difference between a center coordinate vector having the origin as a start point and the center coordinate as an end point, and the magnetic vector. It is preferable.

In this case, the radius of the locus circle can be calculated easily and accurately.

[0023] Further, the three-axis magnetic sensor is preferably constituted by a magneto 'impedance' sensor element.

In this case, it is possible to obtain a magnetic gyro with higher accuracy, higher sensitivity, higher response, and smaller size.

That is, since the magneto-impedance sensor element (Ml element) is highly sensitive, it can detect weak geomagnetism with high accuracy. Furthermore, since the magneto 'impedance' sensor element is small, a small three-axis magnetic sensor can be obtained. This also makes it possible to fit the magnetic gyro in the IC chip.

The three-axis magnetic sensor can be formed by disposing the three magneto 'impedance' sensor elements so that their magnetic sensitive directions are in the three-axis directions orthogonal to each other.

[0024] The three-axis magnetic sensor is not limited to the magneto-impedance sensor element, and can be configured using various magnetic detection elements such as a Hall element, a magnetoresistive element, and a flux gate.

Example

[0025] A magnetic gyro according to an embodiment of the present invention will be described with reference to Figs. The magnetic gyro 1 of this example includes a three-axis magnetic sensor 2, a memory 3, a rotation axis calculation means 4, a rotation angle calculation means 5, and an angular velocity calculation means 6 as shown in FIG.

[0026] The triaxial magnetic sensor 2 detects geomagnetism as magnetic vectors m, m, m in the triaxial orthogonal coordinate system 10 fixed to the measurement object shown in FIG.

one two Three

The above memory 3 is stored in time series by the 3-axis magnetic sensor 2 when the measured object moves as indicated by the arrow V in Fig. 1 around an arbitrary rotation axis K passing through the origin O of the 3-axis orthogonal coordinate system 10. The data of magnetic vectors m, m, m detected in is stored.

one two Three

[0027] The rotation axis calculation means 4 is a magnetic vector m, m stored in the memory 3 at three or more different time points.

1 2

Calculate the rotation axis K based on the data of m.

Three

The rotation angle calculation means 5 calculates the rotation angle of the object to be measured about the rotation axis K based on the magnetic vector data m, m, m.

one two Three

[0028] The angular velocity calculation means 6 is based on the rotation angle of the measured object at two different time points calculated by the rotation angle calculation means 5 and the difference in the collection time of the magnetic vector data at the two time points. Then, the rotational angular velocity of the object to be measured about the rotation axis K is calculated.

The three-axis magnetic sensor 2 is constituted by a magneto-impedance sensor element 20 as shown in FIG. That is, the three-axis magnetic sensor 2 is configured so that the three magneto 'impedance' sensor elements 20 are in the three-axis directions (X-axis direction, Y-axis direction, Z-axis direction) in which the respective magnetic sensing directions are orthogonal to each other. It is formed by arranging. In FIG. 5, electronic components and wiring other than the magneto-impedance sensor element 20 are omitted.

As shown in FIGS. 6 and 7, the magneto-impedance sensor element 20 includes a magnetic sensing body 21 and a detection coil 22 wound around the magnetic sensing body 21. The magnetic sensitive body 21 penetrates through an insulator 23 having an epoxy resin and the like, and the detection coil 22 is disposed on the outer peripheral surface of the insulator 23. As the magnetosensitive member 21, for example, Co Fe Si B having a length of 1. Omm and a wire diameter of 20 μm is used.

68.1 4.4 12.5 1 Use amorphous wire made of alloy.

5.0

[0031] Magnet'impedance sensor element 20 has a so-called MI (Magneto) in which an induced voltage corresponding to the magnitude of the magnetic field acting on the element is generated in the detection coil 22 in accordance with a change in the current applied to the magnetic sensing element 21. -Magnetic sensing using impedance phenomenon. This Ml phenomenon is caused by a magnetic field having an electron spin arrangement in the circulation direction with respect to the supplied current direction. It is generated for the magnetic sensitive material 21 that is a material strength. When the energization current of the magnetosensitive body 21 is suddenly changed, the magnetic field in the circulation direction changes abruptly, and the change in the spin direction of electrons occurs according to the peripheral magnetic field due to the effect of the magnetic field change. A phenomenon in which changes in the internal magnetic field, impedance, etc. of the magnetic sensitive member 21 at that time occur is the Ml phenomenon.

In this example, by measuring the induced voltage generated between the electrodes 221 and 222 at both ends of the detection coil 22 when a pulsed current (pulse current) is passed through the magnetosensitive body 21. Detect the strength of the magnetic field. In this magnetic detection method, an induced voltage generated in the detection coil 22 is measured when the pulse current supplied to the magnetosensitive body 21 falls.

[0033] The magneto-impedance sensor element 20 has a depth of 50 to 150 as shown in FIG.

It is formed on an element substrate 240 provided with a groove-like recess 24 having a substantially rectangular cross section of / z m. The recess 24 is filled with an insulator 23, and a magnetosensitive body 21 is embedded in the insulator 23.

A conductive pattern is continuously formed in a spiral shape on the inner peripheral surface of the recess 24 and the side surface of the insulator 23 disposed at the position of the opening of the recess 24, and this conductive pattern is formed around the magnetic body 21. The detection coil 22 for winding is configured.

[0034] As a method of forming the conductive pattern of the detection coil 22, for example, the following method is available. That is, after depositing a conductive metal thin film on the inner peripheral surface of the recess 24, an etching process is performed to form a conductive pattern. Thereafter, the insulator 23 and the magnetic sensitive body 21 are disposed in the recess 24. Then, after depositing a conductive metal thin film on the side surface of the insulator 23, an etching process is performed to form a conductive pattern. At this time, the conductive pattern formed on the inner peripheral surface of the recess 24 and the conductive pattern formed on the side surface of the insulator 23 are made to be continuous spirally.

The inner diameter of the detection coil 22 of this example has 66 μm as a circle-equivalent inner diameter that is the diameter of a circle having the same cross-sectional area as that of the recess 24. The line width and the line width of the detection coil 22 are both 25 m. Note that in FIG. 6, consideration for the line width and the line width is omitted.

Next, a method for detecting the posture change amount and posture change speed of the measurement object using the magnetic gyro 1 of this example will be specifically described. As shown in FIG. 1, the magnetic gyro 1 accumulates the above three-axis magnetic sensor 2 and the magnetic vector data detected by the three-axis magnetic sensor 2, and based on these, changes in the posture of the object to be measured and And a computer 11 that performs a calculation for calculating a posture change speed. That is, the computer 11 is provided with the memory 3, the rotation axis calculation means 4, the rotation angle calculation means 5, and the angular velocity calculation means 6. The rotation angle calculation means 5 includes a rotation center coordinate calculation means 51 and a radius calculation means 52 described later.

The memory 3 is composed of hardware, and the rotation axis calculation means 4, the rotation angle calculation means 5, and the angular velocity calculation means 6 are constructed as calculation programs in software.

[0037] The three-axis magnetic sensor 2 is fixed to a part of the measurement object, and detects the geomagnetism as the magnetic vectors m, m, m at regular time intervals At. Magnetic vector m, m, m

1 2 3 1 2 3 A vector whose origin is the origin O of the 3-axis Cartesian coordinate system 10 fixed to the measurement object. At this time, when the object to be measured moves and changes its posture, a plurality of magnetic vectors m, m, and m detected in time series are different from each other.

one two Three

This data of magnetic vectors m, m, m detected in time series is stored in computer 11.

one two Three

Is sent to memory 3 and stored as time-series data.

Next, the rotation axis K of the object to be measured is calculated by the rotation axis calculation means 4 based on the magnetic vector data at three or more different points accumulated in the memory 3.

That is, for example, data of magnetic vectors at three different time points (t, t + A t, t + 2 At) are read from the memory 3. The magnetic vector at time t is m = (m, m, m)

1 lx ly lz time t + At the magnetic vector at t + A t is m2 (m, m, m),

2 2x 2y 2z

Let the air vector be m = (m, m, m).

3 3x 3y 3z

[0039] The end points M, M, M of these magnetic vectors are one in the three-magnetic orthogonal coordinate system 10.

one two Three

It exists on the data plane S and exists on the circumference of one locus circle Q. This is the axial force rotation axis K that is orthogonal to the data plane S and passes through the center of the locus circle Q.

In addition, the magnetic vector data can be drawn as an average orbital circle passing through three forces, which are three here, and the more magnetic vector data, the more accurate the calculation is possible. It becomes. [0040] Therefore, first, as shown in FIG. 4, the difference vector n, which is the difference between the magnetic vectors m and m,

1 2 1

Then, a difference vector n which is a difference between the magnetic vectors m and m is calculated. And the following formula (1

3 2 2

) And (2), the X, Y, and Ζ components of the difference vectors n and n can be organized.

1 2

[0041] n = m— m = (m — m, m — m, m — m) = (n, n, n)

1 1 2 lx 2x ly 2y lz 2z lx ly lz

••• (1)

n = m— m = (m — m, m — m, m — m) = (n, n, n)

2 3 2 3x 2x 3y 2y 3z 2z 2x 2y 2z

••• (2)

[0042] Then, by taking the outer product n X n of the difference vector n and the difference vector n, a difference beta is obtained.

1 2 1 2

As a vector perpendicular to n, n, that is, a vector perpendicular to the data plane S,

1 2

Couttle k can be obtained as shown in equation (3) below.

k = n X n = (, η n — n n n n — n n n n — n n)

1 2 ly 2z lz 2y lz 2x lx 2z lx 2y ly 2x

= (k, k, k) (3)

one two Three

A straight line that is parallel to the rotation axis vector k thus obtained and passes through the origin O of the three-axis orthogonal coordinate system 10 is the rotation axis K. The point force at which the rotation axis K and the data plane S intersect is the center coordinate C of the trajectory circle Q. Therefore, the rotation center coordinate calculation means 51 included in the rotation angle calculation means 5 obtains the center coordinate C as an intersection of the rotation axis K and the data plane S as follows.

[0044] As shown in Fig. 3, the size of the center coordinate vector OC is the inner product of the rotation axis vector k and the magnetic vector m (or m or m) having the end point M (or M or M) on the locus circle Q.

1 2 3 1 2 3 The direction of the center coordinate vector OC is the same as the rotation axis vector k. Therefore, if the central coordinate vector OC is set as the vector ak, the following equation (4) is established. Here, a is an arbitrary coefficient.

k-ak = k-m (4)

1

[0045] From this equation (4), the coefficient a can be obtained as in the following equation (5).

a = (mk + mk + mk) / (k ² + k ² + k ² )… (5)

x x y y z z x y z

Since the center coordinate vector OC in the data plane S is equal to ak, the center coordinate C (center coordinate vector OC) is obtained from (ak, ak, ak).

[0046] The center coordinate C obtained by the center coordinate calculation means 51 in this way is used as the radius calculation method. Output to stage 52. Then, the center coordinate vector OC, whose center is C, which is the center of the locus circle Q, and the magnetic vector whose end point is the point M (or M or M) on the circumference of the locus circle Q are shown.

one two Three

The radius R of the trajectory circle Q is calculated from the difference from Torr m (or m or m) by the following formula (6).

one two Three

The

R ² = (m-OC) ² = (m— OC) ² = (m-OC) ² ... (6)

one two Three

[0047] Here, only one magnetic vector may be used for the calculation, but the above three data m, m

1

By calculating the average using m, more accurate calculation is possible. 4 or more

twenty three

By calculating the average of the radius R calculated based on the magnetic vector data, it is possible to perform more accurate calculation.

Based on the radius R obtained as described above, the rotation angle calculating means 5 calculates the rotation angle as follows.

For example, as shown in FIG. 4, the magnetic vector is changed from m to t

When changing to 1 m, the rotation angle Θ in the locus circle Q is calculated by the following equation (7).

2

[0049] [Equation 1]

[0050] The above equation (7) is inscribed in the locus circle Q as shown in FIG.

1 2 Applying the sine theorem to a right triangle M M G with two endpoints M and M

1 2 1 2

Can get more. That is, in the triangle M M G, the following equation (8) is established. here

1 2

The line segment M G corresponds to the diameter 2R of the locus circle Q. And corner M GM and corner M CM

Since 1 1 2 1 2 has a relationship between the circumferential angle and the central angle, the angle M GM is the angle M CM (ie, the rotation angle Θ)

1 2 1 2

Half of that.

[0051] [Equation 2] ... (8)

Therefore, the above equation (7) is derived from this equation (8), and the rotation angle Θ can be obtained. This rotation angle Θ signal is output from output terminal P1 (Fig. 1).

As described above, since the rotation axis K and the rotation angle Θ around the rotation axis K can be obtained, the amount of change in the posture of the measured object from time t to time t + Δ is divided.

Further, using this result, in the angular velocity calculation means 6, the rotation angle Θ is calculated as time.

By dividing by At, the angular velocity ω can be obtained. That is, Θ ′ = 0 Z At. This angular velocity ω signal is output from output terminal P2.

As described above, since the rotation axis Κ and the rotation angular velocity ω around the rotation shaft 、 can be obtained, the posture change speed of the measured object is divided.

Next, the function and effect of this example will be described.

The magnetic gyro 1 includes the triaxial magnetic sensor 2, the memory 3, the rotation axis calculation means 4, and the rotation angle calculation means 5. Based on the geomagnetism detected by the three-axis magnetic sensor 2, a change in the posture of the measured object is detected. Under normal circumstances, geomagnetism basically has a certain direction and size with respect to the ground. Therefore, when the attitude of the measured object, that is, the attitude of the three-axis orthogonal coordinate system 10 changes, the magnetic vector in the three-axis orthogonal coordinate system 10 changes in response to the change in attitude. . By detecting this changing magnetic vector, it is possible to accurately measure changes in the posture of the measured object.

[0055] The change in the posture of the measured object can be specified by an arbitrary rotation angle Θ around an arbitrary rotation axis Κ.

Therefore, in the magnetic gyro 1 as described above, the rotation axis 手段 is calculated by the rotation axis calculation means 4. The memory 3 stores magnetic vector data at three or more different time points necessary for calculating the rotation axis Κ. Further, the rotation angle calculation means 5 allows the measurement object to be measured around the rotation axis Κ. The rotation angle Θ is calculated based on the magnetic vector data.

As described above, since the rotation axis Κ and the rotation angle Θ around the rotation axis できる can be obtained, the change in the posture of the measured object can be measured.

[0056] Further, unlike the conventional mechanical gyro using the kinematic principle, the magnetic gyro can measure a change in the posture of the measurement object based on the geomagnetism. Therefore, even if mechanical vibrations or impacts other than the rotational motion to be measured are applied, accurate measurement without reacting to these can be ensured.

[0057] Further, since the magnetic gyro 1 uses the three-axis magnetic sensor 2, it does not require a complicated mechanism or a lot of electric power unlike a mechanical type. Therefore, downsizing and low cost can be easily achieved. As a result, it can be easily incorporated into, for example, portable electronic devices that are becoming smaller and higher in density.

[0058] Further, since the magnetic gyro 1 has the angular velocity calculation means 6, the rotational angular velocity ω of the measured object can be easily detected. Therefore, it is possible to detect the posture change speed as well as the posture change amount of the measured object.

The rotation angle calculation means 5 includes a rotation center coordinate calculation means 51 and a radius calculation means 52, and is configured to calculate the rotation angle Θ using these as described above. Thus, the rotation angle Θ can be calculated easily and accurately.

[0059] Further, since the three-axis magnetic sensor 2 is composed of the magneto 'impedance' sensor element 20, it is possible to obtain a magnetic gyro 1 with higher accuracy, higher sensitivity, higher response, and smaller size. That is, since the magneto 'impedance' sensor element 20 has high sensitivity, it can detect weak geomagnetism with high accuracy. Furthermore, since the magneto 'impedance' sensor element 20 is small, a small three-axis magnetic sensor 2 can be obtained. This also makes it possible to fit the magnetic gyro 1 inside the IC chip.

[0060] According to this example as described above, it is possible to provide a magnetic gyro which is excellent in measurement accuracy and can be easily miniaturized.

[0061] The magnetic gyro of the present invention is not limited to the above-described embodiment, and various modes are conceivable. Also, the above-described embodiment is merely an example of the calculation method of the rotation angle and the rotation angular velocity. That is, for example, the three-axis magnetic sensor includes, for example, a Hall element, a magnetoresistive element, and a flat element. Can be configured by other than magnet, impedance sensor element such as tas gate

[0062] In addition, the interval between magnetic vector sampling times by the three-axis magnetic sensor is not necessarily constant. Further, the number of magnetic vector data used for the calculation is not limited to three, and may be four or more. In calculating the data plane S, trajectory circle Q, radius R, etc., extremely high-precision measurements can be made by taking measures such as taking averages using as many magnetic vector data as possible. Is possible.

[0063] The magnetic gyro of the present invention is mounted on a portable electronic device such as a mobile phone or a PDA, for example, so that the posture change amount and the posture change speed detected by the magnetic gyro Various input signals can be used.

In addition, for example, by mounting the magnetic gyro on the camera, the posture of the subject in the frame can be corrected or camera shake can be prevented using the detected posture change amount and posture change speed. Can do.

[0064] Further, for example, by installing the magnetic gyro in the robot, the detected posture change amount and posture change speed can be used for robot posture control and the like.

In addition, the magnetic gyro can be mounted on various objects to be measured such as vehicles, robots, airplanes, and ships.

Claims

The scope of the claims

[1] A three-axis magnetic sensor that detects geomagnetism as a magnetic vector in a three-axis orthogonal coordinate system fixed to the object to be measured;

And a rotation angle calculation means for calculating a rotation angle of the object to be measured around the rotation axis based on data of the magnetic vector.

[2] In Claim 1, based on the rotation angle of the object to be measured at two different time points calculated by the rotation angle calculating means and the difference between the sampling times of the magnetic vector data at the two time points. A magnetic gyro comprising angular velocity calculation means for calculating a rotation angular velocity of the object to be measured around the rotation axis.

[3] The magnetic gyro according to claim 2, wherein the time interval for collecting the magnetic vector data is constant.

[4] In any one of claims 1 to 3, the rotation axis calculation means calculates two difference vectors that are differences between two magnetic vectors among the magnetic vectors at three or more different time points, A magnetic gyro characterized by calculating a rotation axis vector in the same direction as the rotation axis by taking the outer product of these two difference vectors.

[5] The rotation angle calculation means according to any one of claims 1 to 4, wherein the rotation angle calculation means includes a data plane defined by coordinate points of the magnetic vector at three or more different points in the three-axis orthogonal coordinate system, and the rotation axis. Rotation center coordinate calculation means for calculating a center coordinate of a trajectory circle passing through the coordinate points of the magnetic vector at three or more different points by calculating an intersection with the rotation axis calculated by the calculation means, and the rotation center coordinates A radius calculating means for calculating a radius of the trajectory circle by calculating a distance between the center coordinate calculated by the calculating means and a coordinate point of the magnetic vector, and calculating the radius calculated by the radius calculating means; Based on the radius of the locus circle and the coordinate points of the magnetic vector at two different time points, A magnetic gyroscope configured to calculate a rotation angle.

[6] In Claim 5, the rotation center coordinate calculation means calculates the center coordinates of the locus circle by taking the inner product of the rotation axis vector calculated by the rotation axis calculation means and the magnetic vector. Magnetic gyro characterized by that.

[7] In Claim 5 or 6, the radius calculation means calculates the difference between the magnetic vector and the center coordinate vector having the origin as the start point and the center coordinate as the end point. A magnetic gyro characterized by calculating a radius of a locus circle.

[8] The magnetic gyro according to any one of claims 1 to 7, wherein the three-axis magnetic sensor is constituted by a magneto impedance sensor element.