JP2022062947A - Magnetism generation source estimation device, and magnetism generation source estimation method - Google Patents

Abstract

To accurately estimate a position of a magnetism generation source even when an installation object of a magnetic sensor is deformed.SOLUTION: A magnetism generation source estimation device 10 includes a plurality of magnetic sensors, a sensor position estimation unit 82, and a magnetism generation source estimation unit 83. The plurality of magnetic sensors is installed on a structure 20 and each measures a magnetism generated by the magnetism generation source 90. The sensor position estimation unit 82 estimates positions of the plurality of magnetic sensors after displacement due to deformation of the structure 20. The magnetism generation source estimation unit 83 estimates a position of the magnetism generation source 90 by using the positions of the plurality of magnetic sensors after displacement estimated by the sensor position estimation unit 82, and the measured magnetism.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technique for estimating the position of a magnetic source using magnetism measured by a magnetic sensor.

Patent Document 1 describes a position / attitude detecting device using a plurality of magnetic sensors.

The apparatus of Patent Document 1 calculates the position and orientation of the magnetic marker using the magnetism detected by a plurality of magnetic sensors.

Japanese Unexamined Patent Publication No. 2016-75664

However, in the apparatus of Patent Document 1, a plurality of magnetic sensors are fixed to a case that does not deform. That is, the positions of the plurality of magnetic sensors do not change.

As described above, in the conventional configuration as shown in Patent Document 1, the position of the object (magnetic source) that generates magnetism is estimated while the position of the magnetic sensor does not change. Therefore, when the object to be installed of the magnetic sensor is deformed and the position of the magnetic sensor changes, the conventional configuration cannot accurately estimate the position of the magnetic source.

Therefore, an object of the present invention is to accurately estimate the position of the magnetic source even if the object to be installed of the magnetic sensor is deformed.

The magnetic source estimation device of the present invention includes a plurality of magnetic sensors, a sensor position estimation unit, and a magnetic source estimation unit. A plurality of magnetic sensors are installed in a deformable structure, and each of them measures the amount of magnetic charge generated by a magnetic source. The sensor position estimation unit estimates the positions of a plurality of magnetic sensors after displacement due to deformation of the structure. The magnetic source estimation unit estimates the position of the magnetic source using the positions of the plurality of magnetic sensors estimated by the sensor position estimation unit after displacement and the measured magnetic amount.

In this configuration, even if the structure is deformed, the positions of the plurality of magnetic sensors after the deformation can be obtained with high accuracy. As a result, the positional relationship between the magnetic source and the plurality of magnetic sensors can be accurately obtained without being affected by the deformation of the structure.

According to the present invention, even if the object to which the magnetic sensor is installed is deformed, the position of the magnetic source can be estimated accurately.

FIG. 1 is a functional block diagram showing an example of the configuration of the magnetic source estimation device according to the first embodiment. FIG. 2A is an end view and a side view of a structure in which the magnetic source estimation device according to the first embodiment is used, and FIG. 2B is a structure according to the first embodiment. It is a cross-sectional view of. FIG. 3 is a diagram showing one aspect of setting the three orthogonal axes of the sensor element. FIG. 4 is a diagram showing an example of position coordinates in an example of a coordinate system set by the sensor position estimation unit. FIG. 5 is a diagram showing an example of the positional relationship between the magnetic source and the plurality of sensor elements in a state where the structure is not deformed. FIG. 6 is a diagram showing an example of the positional relationship between the magnetic source and the plurality of sensor elements in a state where the structure is deformed. FIG. 7 is a flowchart showing the main flow of the method for estimating the magnetic source according to the first embodiment. FIG. 8 is a specific flowchart of position estimation. FIG. 9 is a functional block diagram showing an example of the configuration of the magnetic source estimation device according to the second embodiment. FIG. 10 is an end view and a side view of a structure in which the magnetic source estimation device according to the second embodiment is used. FIG. 11 is a diagram showing a state in which the structure is deformed in the magnetic source estimation device of the second embodiment. FIG. 12 is a flowchart showing the main flow of the method for estimating the magnetic source according to the second embodiment. FIG. 13 is an end view and a side view of a structure in which the magnetic source estimation device according to the third embodiment is used. FIG. 14 is an end view and a side view of a structure in which the magnetic source estimation device according to the fourth embodiment is used.

(First Embodiment)
The magnetic source estimation device and the magnetic source estimation method according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a functional block diagram showing an example of the configuration of the magnetic source estimation device according to the first embodiment.

As shown in FIG. 1, the magnetic source estimation device 10 includes a plurality of sensor elements (sensor element 311 and sensor element 312, sensor element 313, sensor element 314, sensor element 321 and sensor element 322, sensor element 323, and sensor element. 324) and a calculation device 80 are provided. Each of the plurality of sensor elements 311-314 and 321-324 is connected to the arithmetic unit 80.

(Structure of structure 20, installation mode of a plurality of sensor elements 311-314, 321-324 in the structure 20, and processing of a plurality of sensor elements 311-314, 321-324).
Each of the plurality of sensor elements 311-314 and 321-324 includes a magnetic sensor and an inertial sensor. For example, the sensor element 311 includes a magnetic sensor 311M and an inertial sensor 311I. The plurality of sensor elements are installed in the structure 20.

FIG. 2A is an end view and a side view of a structure in which the magnetic source estimation device according to the first embodiment is used, and FIG. 2B is a structure according to the first embodiment. It is a cross-sectional view of. The cross-sectional view shown in FIG. 2B is a cross-sectional view cut along a plane parallel to the end face (end face cross-sectional view) and a cross-sectional view cut along a plane orthogonal to the end face (side cross-sectional view).

As shown in FIGS. 2A and 2B, the plurality of sensor elements 311-314 and 321-324 are installed in the structure 20. The structure 20 has a cylindrical shape that can be elastically deformed. Here, elastically deformable means bending, partial denting, contracting, and stretching due to stress. Further, the elastic deformability in this case means that the amount of deformation changes according to the magnitude of the applied stress. The structure 20 is made of, for example, a resin having a predetermined elastic modulus and flexibility. Further, the structure 20 has magnetic permeability.

The structure 20 has one circular end face and the other end face, respectively. The structure 20 has a shape extending along a direction connecting one end face and the other end face. That is, the direction connecting one end face and the other end face is the stretching direction of the structure 20.

The structure 20 has an inner wall surface 201 and an outer wall surface 202. The space surrounded by the inner wall surface 201 becomes the hollow portion 200 of the structure 20. The structure 20 is not limited to a cylindrical shape and may be elastically deformable. However, the configuration of the present invention is more effective when the internal state of the structure 20 cannot be easily grasped by imaging from the outside, such as a shape having a hollow.

The plurality of sensor elements 311-314 and 321-324 are installed on the outer wall surface 202 of the structure 20. At this time, the plurality of sensor elements 311-314 and 321-324 are installed in the structure 20 so as to be able to detect the magnetic field (magnetic field) generated by the magnetic generation source.

As an example of more specific installation, the plurality of sensor elements 311-314 are installed at the first position in the stretching direction of the structure 20. The plurality of sensor elements 311-314 are installed at intervals along the circumferential direction of the structure 20. For example, the plurality of sensor elements 311-314 are installed at an angular interval of 90 ° along the circumferential direction.

The plurality of sensor elements 321-324 are installed at the second position in the stretching direction of the structure 20. The second position is a position separated from the first position by a predetermined distance in the stretching direction. The plurality of sensor elements 321-324 are installed at intervals along the circumferential direction of the structure 20. For example, the plurality of sensor elements 321-324 are installed at an angular interval of 90 ° along the circumferential direction.

The magnetic sensors of the plurality of sensor elements 311-314 and 321-324 measure the magnetic field (magnetic field) at the installation position of the sensor element. Each magnetic sensor outputs a magnetic measurement value (magnetic field strength, etc.) to the arithmetic unit 80. At this time, each magnetic sensor associates the identification information of the sensor element to which it belongs and outputs the magnetic measurement value.

The inertial sensors of the plurality of sensor elements 311-314 and 321-324 measure physical quantities due to the inertial force applied to the sensor elements. Each inertial sensor outputs the measured physical quantity to the arithmetic unit 80. More specifically, the inertial sensor includes an acceleration sensor and an angular velocity sensor. The acceleration sensor measures the acceleration applied to the sensor element. The acceleration is a triaxial acceleration. Each acceleration sensor outputs the measured acceleration to the arithmetic unit 80.

The angular velocity sensor measures the angular velocity applied to the sensor element. The angular velocity is the angular velocity around three axes. Each angular velocity sensor outputs the measured angular velocity to the arithmetic unit 80.

FIG. 3 is a diagram showing one aspect of setting the three orthogonal axes of the sensor element. As shown in FIG. 3, the sensor element 300 (sensor element having the same configuration as a plurality of sensor elements 311-314 and 321-324) has an xs axis (sensor system x axis) and an ys axis (sensor system y) orthogonal to each other. Axis) and zs axis (sensor system z axis) are set. The zs axis is an axis orthogonal to the main surface of the housing of the sensor element 300 (the installation surface on the structure 20), and the xs axis and the ys axis are parallel to the main surface of the housing of the sensor element 300. It is an axis.

The acceleration sensor measures the acceleration in the xs-axis direction, the acceleration in the ys-axis direction, and the acceleration in the zs-axis direction as the above-mentioned three-axis acceleration.

The angular velocity sensor measures the angular velocity θs around the xs axis, the angular velocity φs around the ys axis, and the angular velocity ψs around the zs axis as the above-mentioned three-axis angular velocity.

The three axes of acceleration and the three axes of angular velocity do not have to coincide. However, when the three axes of acceleration and the three axes of angular velocity match, the acceleration calibration process described later becomes easy.

The acceleration sensor and the angular velocity sensor of each sensor element associate the identification information of the sensor element to which each sensor element belongs, and output the acceleration and the angular velocity. Further, each set of the acceleration sensor and the angular velocity sensor outputs the acceleration and the angular velocity so as to be synchronized with the magnetic measurement value of the magnetic sensor of the sensor element to which the acceleration sensor and the angular velocity sensor belong.

(Configuration and processing of arithmetic unit 80)
The arithmetic unit 80 is realized by, for example, a personal computer, a microcomputer, or the like. The arithmetic unit 80 includes a magnetic measurement value storage unit 81, a sensor position estimation unit 82, and a magnetic source estimation unit 83.

The magnetic measurement value storage unit 81 is connected to magnetic sensors of a plurality of sensor elements. The magnetic measurement value storage unit 81 receives and stores the magnetic measurement values measured by the magnetic sensors of the plurality of sensor elements 311-314 and 321-324. At this time, the magnetic measurement value storage unit 81 stores the identification information of the plurality of sensor elements 311-314 and 321-324 in association with the magnetic measurement value measured in each of them.

The magnetic measurement value storage unit 81 can be omitted. In this case, the magnetic measurement values measured by the magnetic sensors of the plurality of sensor elements 311-314 and 321-324 are received by the magnetic source estimation unit 83.

The sensor position estimation unit 82 is connected to the inertial sensors of the plurality of sensor elements 311-314 and 321-324. In the following, a case where the inertial sensor includes an acceleration sensor and an angular velocity sensor will be described as a specific example. The sensor position estimation unit 82 receives the acceleration measurement value and the angular velocity measurement value from the plurality of sensor elements 311-314 and 321-324.

The sensor position estimation unit 82 estimates the position coordinates of the plurality of sensor elements 311-314 and 321-324 in the preset coordinate system.

FIG. 4 is a diagram showing a position coordinate example in an example of the coordinate system set by the sensor position estimation unit. As shown in FIG. 4, the sensor position estimation unit 82 sets the coordinates of a predetermined reference point to the reference origin Po in a state where the structure 20 is not deformed (stationary state: reference state). More specifically, one point on the central axis extending in the stretching direction in the hollow portion 200 of the structure 20 is set as the reference origin Po. Further, a direction parallel to the stretching direction is set in the z-axis direction, and two directions orthogonal to the z-axis direction and orthogonal to each other are set to the x-axis direction and the y-axis direction, respectively.

In this coordinate system, the position coordinates Pss and the attitude ATss in the reference state are set in the plurality of sensor elements 311-314 and 321-324. Specifically, the sensor element 311 is set with the position coordinates Pss ₃₁₁ and the attitude ATss ₃₁₁ , the sensor element 312 is set with the position coordinates Pss ₃₁₂ and the attitude ATss ₃₁₂ , and the sensor element 313 is set with the position coordinates Pss ₃₁₃ . , The posture ATss ₃₁₃ is set, and the position coordinates Pss ₃₁₄ and the posture ATss ₃₁₄ are set in the sensor element 314. The sensor element 321 is set with the position coordinates Pss ₃₂₁ and the posture ATss ₃₂₁ , the sensor element 322 is set with the position coordinates Pss ₃₂₂ and the posture ATss ₃₂₂ , and the sensor element 323 is set with the position coordinates Pss ₃₂₃ and the posture ATss ₃₂₃ . Is set, and the position coordinates Pss ₃₂₄ and the attitude ATss ₃₂₄ are set in the sensor element 324.

Further, the sensor position estimation unit 82 stores in advance the relationship between the coordinate system set by the reference origin Po and the coordinate systems of the plurality of sensor elements 311-314 and 321-324. Then, the sensor position estimation unit 82 stores, for example, a transformation matrix between these coordinate systems.

The sensor position estimation unit 82 detects whether or not there is a change in the acceleration and the angular velocity from the sensor element. The sensor position estimation unit 82 outputs the position coordinates of the reference state as the position coordinates of the sensor element if there is no change in the acceleration and the angular velocity from the reference state in the sensor element to be positioned.

If there is a change in acceleration and angular velocity from the reference state in the sensor element to be positioned, the sensor position estimation unit 82 estimates the changed position coordinates using the position coordinates, acceleration, and angular velocity in the reference state. Then, the sensor position estimation unit 82 outputs the estimated position coordinates after the change as the position coordinates of the sensor element.

Further, if there is no change in acceleration and angular velocity from a certain state (for example, a state in which the structure 20 is deformed) in the sensor element to be positioned estimated, the sensor position estimation unit 82 continuously obtains the position coordinates in this state. , Output as the position coordinates of the sensor element.

Further, if there is a further change in the acceleration and the angular velocity from a certain state (for example, a state in which the structure 20 is deformed) in the sensor element to be positioned estimated, the sensor position estimation unit 82 determines the position coordinates and the acceleration in a certain state. The angular velocity is used to estimate the position coordinates after further changes. Then, the sensor position estimation unit 82 outputs the estimated position coordinates after the further change as the position coordinates of the sensor element.

(Example of estimation method of position coordinates when there is a change in acceleration and angular velocity)
When the acceleration and the angular velocity change, the sensor position estimation unit 82 estimates the position coordinates of the sensor element more specifically by the following method. The sensor position estimation unit 82 acquires the acceleration measured by the sensor element together with the position coordinate Pss and the attitude ATss of the sensor element in the reference state. Since the sensor element is not displaced in this reference state, the sensor position estimation unit 82 extracts and stores the acceleration in this reference state as the gravitational acceleration.

The sensor position estimation unit 82 estimates the amount of attitude change by integrating (first-order integration) the angular velocities that are sequentially input. The sensor position estimation unit 82 estimates the posture after displacement of the sensor element by correcting (for example, adding) the posture ATss in the reference state with the amount of change in posture.

The sensor position estimation unit 82 corrects the gravitational acceleration by using the posture. The sensor position estimation unit 82 calibrates the acceleration acquired in parallel with the angular velocity for estimating the attitude with the corrected gravitational acceleration. For example, the corrected gravitational acceleration is subtracted from the measured 3-axis acceleration.

The sensor position estimation unit 82 calculates the speed by integrating the corrected acceleration, and estimates the amount of change in the position of the sensor element by integrating the speed. In other words, the sensor position estimation unit 82 estimates the amount of change in the position of the sensor element by integrating the corrected acceleration in the second order.

The sensor position estimation unit 82 estimates the position coordinates after the displacement of the sensor element by correcting (for example, adding) the position coordinates Pss in the reference state with the position change amount.

In the above description, the case of displacement from the reference state is shown, but even when displacement from one state to another state, the physical quantity in the reference state is replaced with the physical quantity in a certain state in the above processing. , The sensor position estimation unit 82 can estimate the position coordinates after the displacement of the sensor element.

By performing such processing, the sensor position estimation unit 82 can accurately estimate the position coordinates of the plurality of sensor elements 311-314 and 321-324 even if the structure 20 is deformed.

The sensor position estimation unit 82 outputs the position coordinates of the plurality of sensor elements 311-314 and 321-324 set or estimated to the magnetic source estimation unit 83.

The magnetic source estimation unit 83 uses the magnetic measurement values of the plurality of sensor elements 311-314 and 321-324 and the position coordinates of the plurality of sensor elements 311-314 and 321-324 to position the magnetic source 90. To estimate.

The magnetic source estimation unit 83 estimates the position coordinates of the magnetic source 90 from the following concept. When the amount of magnetism of the magnetic source 90 is known, the magnetic field strength according to the position of the magnetic source 90 and the posture of the magnetic source 90 (solid angle of the magnetic moment M) can be known. That is, the position of the magnetic source 90 and the posture of the magnetic source 90 (solid angle of the magnetic moment M) can be uniquely calculated from the magnetic measurement value measured by the magnetic sensor of the sensor element. The position coordinate P ₉₀ of the magnetic source 90 is determined by the x-axis coordinate, the y-axis coordinate, and the z-axis coordinate. That is, the position coordinate P ₉₀ of the magnetic source 90 has three unknowns. Further, the posture of the magnetic source 90 has two unknowns consisting of posture angles θ and φ representing a solid angle. Therefore, if the position coordinates of the five or more sensor elements and the distance between the five or more sensor elements and the magnetic source 90 are known, these five unknowns, that is, the position coordinates of the magnetic source 90 and the magnetic source 90 are known. The posture of 90 can be estimated by using the minimum square method or the like.

Utilizing this, the magnetic source estimation unit 83 uses the magnetic measurement values of the plurality of sensor elements 311-314 and 321-324 and the magnetic charge of the magnetic source 90 together with the attitude of the magnetic source 90 and the magnetic source. Estimate the position coordinates P ₉₀ of 90.

Specifically, the magnetic source estimation unit 83 is in a state where the structure 20 is deformed and a state in which the structure 20 is not deformed, and the position coordinates P ₉₀ of the magnetic source 90 are as follows. To estimate.

FIG. 5 is a diagram showing an example of the positional relationship between the magnetic source and the plurality of sensor elements in a state where the structure is not deformed. FIG. 6 is a diagram showing an example of the positional relationship between the magnetic source and the plurality of sensor elements in a state where the structure is deformed.

As shown in FIGS. 5 and 6, a magnetic source 90 is inserted into the hollow portion 200 of the structure 20. The magnetic source 90 is attached to, for example, the tip of the rod-shaped body 900. By inserting the rod-shaped body 900, the magnetic source 90 is inserted into the hollow portion 200 of the structure 20. This corresponds to, for example, simulating a state in which a catheter is inserted into an organ such as a blood vessel.

(The state where the structure 20 is not deformed)
In the example shown in FIG. 5, the magnetic source 90 does not come into contact with the inner wall surface 201 of the structure 20, and the structure 20 is not deformed.

If the structure 20 is not deformed, the position coordinates and attitudes of the plurality of sensor elements 311-314 and 321-324 remain in the reference state, and there is no change in acceleration or angular velocity. In this case, the position coordinates of the plurality of sensor elements 311-314 and 321-324 in the reference state are input to the magnetic source estimation unit 83. The magnetic source estimation unit 83 estimates the position coordinates P ₉₀ of the magnetic source 90 by using these position coordinates and the magnetic measurement values of each sensor element.

(The state where the structure 20 is deformed)
In the example shown in FIG. 6, the magnetic source 90 is in contact with the inner wall surface 201 of the structure 20, and the structure 20 is deformed by the stress received from the rod-shaped body 900 and the magnetic source 90.

When the structure 20 is deformed, the position coordinates and orientations of the plurality of sensor elements 311-314 and 321-324 change from the reference state. This also changes the acceleration and angular velocity. The sensor position estimation unit 82 uses the changes in acceleration and angular velocity to calculate the position coordinates and attitudes of the plurality of sensor elements 311-314 and 321-324 after displacement, as described above. For example, in the case of FIG. 6, the sensor position estimation unit 82 calculates the position coordinates Psb ₃₁₁ and the attitude ATsb ₃₁₁ after the displacement of the sensor element 311 by using the acceleration and the angular velocity from the sensor element 311. Similarly, the sensor position estimation unit 82 calculates the position coordinates Psb ₃₁₂ and the attitude ATsb ₃₁₂ after the displacement of the sensor element 312 by using the acceleration and the angular velocity from the sensor element 312, and calculates the acceleration and the angular velocity from the sensor element 313. Using, the position coordinates Psb ₃₁₃ and the attitude ATsb ₃₁₃ after the displacement of the sensor element 313 are calculated, and the position coordinates Psb ₃₁₄ and the attitude ATsb ₃₁₄ after the displacement of the sensor element 314 are calculated using the acceleration and the angular velocity from the sensor element 314. calculate. Further, similarly, the sensor position estimation unit 82 has the position coordinates Psb ₃₂₁ and the attitude ATsb ₃₂₁ after the displacement of the sensor element 321, the position coordinates Psb ₃₂₂ after the displacement of the sensor element 322, the attitude ATsb ₃₂₂ , and the sensor element 323 after the displacement. Position coordinates Psb ₃₂₃ , attitude ATsb ₃₂₃ , and position coordinates Psb ₃₂₄ and attitude ATsb ₃₂₄ after displacement of the sensor element 324 are calculated. The sensor position estimation unit 82 outputs the calculated position coordinates of the plurality of sensor elements 311-314 and 321-324 after displacement to the magnetic source estimation unit 83.

The magnetic source estimation unit 83 estimates the position coordinates P ₉₀ of the magnetic source 90 by using the position coordinates after these displacements and the magnetic measurement values of each sensor element.

As described above, by using the configuration of the present embodiment, the position coordinates P ₉₀ of the magnetic source 90 can be estimated accurately regardless of the presence or absence of deformation of the structure 20.

At this time, the magnetic source estimation unit 83 may combine the sensor elements used for estimating the position coordinates P ₉₀ of the magnetic source 90 based on predetermined conditions. For example, the magnetic source estimation unit 83 may perform processing such as combining sensor elements having a large magnetic measurement value, combining sensor elements having significantly different magnetic measurement values, or combining sensor elements at positions different in the stretching direction. good. By performing these processes, the magnetic source estimation unit 83 can improve the estimation accuracy. It should be noted that this combination method is an example, and other combination methods are also possible as appropriate.

Further, in the above description, the case where the magnetic charge generated by the magnetic source 90 is known has been shown, but even when the magnetic charge is unknown, the position coordinates P ₉₀ of the magnetic source 90 can be estimated. In this case, the magnetic source estimation unit 83 uses the magnetic measurement values and the position coordinates of six or more sensor elements, and sets the position coordinates P ₉₀ , the attitude angles θ, φ, and the magnetic quantity of the magnetic source 90 as unknowns. Perform an estimation operation.

With this configuration and processing, the magnetic source estimation device 10 can accurately estimate not only the position coordinate P ₉₀ of the magnetic source 90 but also the magnetic charge generated by the magnetic source 90.

(Magnetic source estimation method)
FIG. 7 is a flowchart showing the main flow of the method for estimating the magnetic source according to the first embodiment. FIG. 8 is a specific flowchart of position estimation. In the specific contents of the processes shown in FIGS. 7 and 8, the specific contents that can be easily understood by the above-mentioned explanation of the configuration will be omitted.

The sensor position estimation unit 82 of the magnetic source estimation device 10 stores the initial positions (position coordinates in the reference state) of the plurality of sensor elements 311-314 and 321-324 (S11).

The plurality of sensor elements 311-314 and 321-324 measure the magnetism from the magnetic source 90, respectively (S121). The magnetic measurement value storage unit 81 stores the magnetic measurement values of the plurality of sensor elements 311-314 and 321-324 (S122).

The plurality of sensor elements 311-314 and 321-324 measure acceleration and angular velocity, respectively (S131). The sensor position estimation unit 82 estimates a plurality of sensor elements 311-314 and 321-324 using the acceleration and angular velocity measured by the plurality of sensor elements 311-314 and 321-324 and the position coordinates of the immediately preceding state. (S132), and update.

More specifically, in the case of a change from the reference state (stationary state: the state in which the structure 20 is not deformed), the plurality of sensor elements 311-314 and 321-324 measure the acceleration in the reference state. (S311), the sensor position estimation unit 82 extracts and stores the gravitational acceleration from the accelerations in these reference states (S312).

The sensor position estimation unit 82 estimates the amount of change in posture of each sensor element using the angular velocity of each sensor element (S313). The sensor position estimation unit 82 estimates the posture of each sensor element from the posture change amount (S314). The sensor position estimation unit 82 corrects the gravitational acceleration using the posture (S315), and calibrates the measured acceleration using the corrected gravitational acceleration (S316).

The sensor position estimation unit 82 estimates the amount of position change using the calibrated measurement acceleration (S317). The sensor position estimation unit 82 estimates the position coordinates using the position coordinates in the reference state and the amount of position change (S318).

The magnetic source estimation unit 83 estimates the position coordinates P ₉₀ of the magnetic source 90 using the position coordinates of the plurality of sensor elements 311-314 and 321-324 and the magnetic measurement values (S14). At this time, the magnetic source estimation unit 83 can estimate the magnetic charge generated by the magnetic source 90 as well as the position coordinates P ₉₀ of the magnetic source 90.

(Second embodiment)
The magnetic source estimation device and the magnetic source estimation method according to the second embodiment of the present invention will be described with reference to the drawings. FIG. 9 is a functional block diagram showing an example of the configuration of the magnetic source estimation device according to the second embodiment. FIG. 10 is an end view and a side view of a structure in which the magnetic source estimation device according to the second embodiment is used.

As shown in FIG. 9, the magnetic source estimation device 10A according to the second embodiment uses a strain sensor instead of the inertial sensor for the magnetic source estimation device 10 according to the first embodiment. It differs in that. Other configurations of the magnetic source estimation device 10A are the same as those of the magnetic source estimation device 10, and the description of the same parts will be omitted.

The magnetic source estimation device 10A includes a plurality of magnetic sensors (magnetic sensor 311M, magnetic sensor 312M, magnetic sensor 313M, magnetic sensor 314M, magnetic sensor 321M, magnetic sensor 322M, magnetic sensor 323M, magnetic sensor 324M), and a plurality of strain sensors. (Strain sensor 41, strain sensor 42, strain sensor 43, strain sensor 43), and a calculation device 80A are provided. A plurality of strain sensors 41-44 correspond to the "deformation detection sensor" of the present invention.

The arithmetic unit 80A includes a magnetic measurement value storage unit 81, a sensor position estimation unit 82A, and a magnetic source estimation unit 83.

As shown in FIG. 10, the plurality of magnetic sensors 311M-314M, 321M-324M, and the strain sensor 41-44 are installed in the structure 20.

The plurality of magnetic sensors 311M-314M and 321M-324M are installed on the outer wall surface 202 of the structure 20. At this time, the plurality of magnetic sensors 311M-314M and 321M-324M are installed in the structure 20 so as to be able to detect the magnetic field (magnetic field) generated by the magnetic generation source. Generally, the plurality of magnetic sensors 311M-314M and 321M-324M are installed in the structure 20 in the same manner as the plurality of sensor elements 311-314 and 321-324 according to the first embodiment.

The plurality of magnetic sensors 311M-314M and 321M-324M output the magnetic measurement value to the magnetic measurement value storage unit 81.

The plurality of strain sensors 41-44 have a long and elastic film shape. The elastic modulus of the plurality of strain sensors 41-44 is preferably lower than the elastic modulus of the structure 20. As a result, the plurality of strain sensors 41-44 can more accurately follow the deformation of the structure 20 and detect the deformation of the structure 20 with high accuracy. The plurality of strain sensors 41-44 are installed on the outer wall surface 202 of the structure 20.

The plurality of strain sensors 41-44 are installed in the structure 20 so that the elongated direction is parallel to the stretching direction of the structure 20. The plurality of strain sensors 41-44 are installed at intervals along the circumferential direction of the structure 20. For example, the plurality of strain sensors 41-44 are installed at an angular interval of 90 ° along the circumferential direction. At this time, the installation positions of the plurality of strain sensors 41-44 and the installation positions of the plurality of magnetic sensors 311M-314M and 321M-324M do not overlap.

FIG. 11 is a diagram showing a state in which the structure is deformed in the magnetic source estimation device of the second embodiment. As shown in FIG. 11, when the structure 20 is deformed, the plurality of strain sensors 41-44 are deformed and distorted in a shape corresponding to the deformation of the structure 20.

The plurality of strain sensors 41-44 generate detection signals according to the strain state (for example, the amount of strain and the direction of strain). The plurality of strain sensors 41-44 output the strain detection signal to the sensor position estimation unit 82A.

The sensor position estimation unit 82A stores the position coordinates Pss of the plurality of magnetic sensors 311M-314M and 321M-324M in the reference state. Further, the sensor position estimation unit 82A determines the relationship between, for example, the combination of the detection signals of the strain sensors 41-44 and the displacement amount (vector amount) at the positions of the magnetic sensors 311M-314M and 321M-324M in the structure 20. I remember.

The sensor position estimation unit 82A detects the displacement amount at the positions of the magnetic sensors 311M-314M and 321M-324M in the structure 20 from the detection signal of the strain sensor 41-44, and the displacement amount and the plurality of magnetic sensors 311M. From the position coordinates Pss of 314M and 321M-324M, the position coordinates after displacement of the plurality of magnetic sensors 311M-314M and 321M-324M are estimated. The sensor position estimation unit 82A outputs the displaced position coordinates of the plurality of estimated magnetic sensors 311M-314M and 321M-324M to the magnetic source estimation unit 83.

The magnetic source estimation unit 83 uses the position coordinates of the magnetic sensors 311M-314M and 321M-324M after displacement and the magnetic measurement values of the magnetic sensors 311M-314M and 321M-324M, and the position coordinates of the magnetic source 90. Estimate P ₉₀ .

With such a configuration and processing, the magnetic source estimation device 10A can accurately estimate the position coordinates P ₉₀ of the magnetic source 90 regardless of the presence or absence of deformation of the structure 20.

(Magnetic source estimation method)
FIG. 12 is a flowchart showing the main flow of the method for estimating the magnetic source according to the second embodiment. In the specific contents of the process shown in FIG. 12, those that can be easily understood by the above-mentioned explanation of the configuration will be omitted.

The sensor position estimation unit 82A of the magnetic source estimation device 10A stores the initial positions (position coordinates in the reference state) of the plurality of sensor elements 311-314 and 321-324 (S11).

The plurality of magnetic sensors 311M-314M and 321M-324M each measure the magnetism from the magnetic source 90 (S121). The magnetic measurement value storage unit 81 stores the magnetic measurement values of the plurality of magnetic sensors 311M-314M and 321M-324M (S122).

The plurality of strain sensors 41-44 detect the strain state of the structure 20 at each installation position (S151). The sensor position estimation unit 82A estimates a plurality of sensor elements 311-314 and 321-324 using the strain state detected by the plurality of strain sensors 41-44 and the position coordinates of the immediately preceding state (S152). Update.

The magnetic source estimation unit 83 estimates the position coordinates P ₉₀ of the magnetic source 90 using the position coordinates of the plurality of sensor elements 311-314 and 321-324 and the magnetic measurement values (S14). At this time, the magnetic source estimation unit 83 can estimate the magnetic charge generated by the magnetic source 90 as well as the position coordinates P ₉₀ of the magnetic source 90.

(Third embodiment)
The magnetic source estimation device according to the third embodiment of the present invention will be described with reference to the drawings. FIG. 13 is an end view and a side view of a structure in which the magnetic source estimation device according to the third embodiment is used.

As shown in FIG. 13, the magnetic source estimation device according to the third embodiment differs from the magnetic source estimation device 10A according to the second embodiment in the installation mode of the strain sensor. Other configurations of the magnetic source estimation device according to the third embodiment are the same as those of the magnetic source estimation device 10A, and the description of the same parts will be omitted.

The plurality of strain sensors 41-44 are installed in the wall of the structure 20. In other words, the plurality of strain sensors 41-44 are built in the structure 20 and integrally molded. Even with such a configuration, the plurality of strain sensors 41-44 can detect the deformation of the structure 20. Therefore, the magnetic source estimation device can accurately estimate the position coordinates P90 of the magnetic source 90 regardless of the presence or absence of deformation of the structure 20.

Further, in this configuration, the plurality of strain sensors 41-44 are installed so as not to overlap the plurality of magnetic sensors 311M-314M and 321M-324M when viewed from a direction orthogonal to the outer peripheral surface of the structure 20. As a result, the influence of the plurality of strain sensors 41-44 on the magnetic field generated by the magnetic source 90 and measured by the plurality of magnetic sensors 311M-314M and 321M-324M can be suppressed. Therefore, the magnetic source estimation device can suppress deterioration of the measurement accuracy of the plurality of magnetic sensors 311M-314M and 321M-324M.

(Fourth Embodiment)
The magnetic source estimation device according to the fourth embodiment of the present invention will be described with reference to the drawings. FIG. 14 is an end view and a side view of a structure in which the magnetic source estimation device according to the fourth embodiment is used.

As shown in FIG. 14, the magnetic source estimation device according to the fourth embodiment differs from the magnetic source estimation device according to the third embodiment in the installation mode of the strain sensor. Other configurations of the magnetic source estimation device according to the fourth embodiment are the same as those of the magnetic source estimation device according to the third embodiment, and the description of the same parts will be omitted.

The magnetic source estimation device according to the fourth embodiment further includes a strain sensor 51 and a strain sensor 52 with respect to the magnetic source estimation device according to the third embodiment. The strain sensor 51 and the strain sensor 52, like the plurality of strain sensors 41-44, have a long film shape and have elasticity. The elastic modulus of the strain sensor 51 and the strain sensor 52 is lower than the elastic modulus of the structure 20.

The strain sensor 51 and the strain sensor 52 are installed in the structure 20 so that the elongated direction is parallel to the circumferential direction of the structure 20. The strain sensor 51 and the strain sensor 52 are installed in the wall of the structure 20. The installation position of the strain sensor 51 and the installation position of the strain sensor 52 are different in the stretching direction of the structure 20.

With such a configuration, the number of distortion sensors can be increased, and installation with a higher degree of freedom becomes possible. As a result, the deformation of the structure 20 can be detected more accurately by the plurality of strain sensors 41-44, 51, 52. Therefore, the magnetic source estimation device can estimate the position coordinates P90 of the magnetic source 90 with higher accuracy regardless of the presence or absence of deformation of the structure 20.

Further, in this configuration, the plurality of strain sensors 41-44, 51, 52 are installed so as not to overlap the plurality of magnetic sensors 311M-314M and 321M-324M when viewed from the direction orthogonal to the outer peripheral surface of the structure 20. Will be done. As a result, the influence of the plurality of strain sensors 41-44, 51, 52 on the magnetic field generated by the magnetic source 90 and measured by the plurality of magnetic sensors 311M-314M and 321M-324M can be suppressed. Therefore, the magnetic source estimation device can suppress deterioration of the measurement accuracy of the plurality of magnetic sensors 311M-314M and 321M-324M.

The installation positions and numbers of the sensor elements, magnetic sensors, inertial sensors, and strain sensors shown in each of the above embodiments are examples, and other installation positions and numbers can be used. Further, in each of the above-described embodiments, the mode in which the inertial sensor is used and the mode in which the strain sensor is used are individually shown. However, it is also possible to use both an inertial sensor and a strain sensor.

10, 10A: Magnetic source estimation device 20: Structure 41, 42, 43, 51, 52: Strain sensor 80, 80A: Arithmetic device 81: Magnetic measurement value storage unit 82, 82A: Sensor position estimation unit 83: Magnetic generation Source estimation unit 90: Magnetic source 200: Hollow part 201: Inner wall surface 202: Outer wall surface 300, 311, 313, 314, 321, 322, 323, 324: Sensor element 311I: Inertivity sensor 311M, 312M, 313M, 314M, 321M, 322M, 323M, 324M: Magnetic sensor 900: Rod-shaped body

Claims (14)

Multiple magnetic sensors installed in a deformable structure that measure the magnetism generated by each magnetic source,
A sensor position estimation unit that estimates the position of the plurality of magnetic sensors after displacement due to deformation of the structure, and a sensor position estimation unit.
A magnetic source estimation unit that estimates the position of the magnetic source using the positions after displacement of the plurality of magnetic sensors estimated by the sensor position estimation unit and the measured magnetism.
A magnetic source estimation device. A plurality of inertial sensors for measuring physical quantities due to inertial forces related to the plurality of magnetic sensors are provided.
The sensor position estimation unit is
Using the measurement results of the plurality of inertial sensors, the positions of the plurality of magnetic sensors after displacement are estimated.
The magnetic source estimation device according to claim 1. The inertial sensor includes an accelerometer.
The sensor position estimation unit is
Using the acceleration measured by the acceleration sensor, the position of the magnetic sensor after displacement is estimated.
The magnetic source estimation device according to claim 2. The inertial sensor includes an angular velocity sensor.
The sensor position estimation unit is
Using the angular velocity measured by the angular velocity sensor, the attitude of the magnetic sensor is estimated.
The acceleration is calibrated with the gravitational acceleration corrected using the estimated posture.
Using the calibrated acceleration, the position of the magnetic sensor after displacement is estimated.
The magnetic source estimation device according to claim 3. The magnetic sensor is a 3-axis magnetic sensor.
The inertial sensor is a 3-axis inertial sensor.
The directions of the three axes of the magnetic sensor and the directions of the three axes of the inertial sensor coincide with each other.
The magnetic source estimation device according to any one of claims 2 to 4. The magnetic sensor and the inertial sensor are housed in an integral housing.
The magnetic source estimation device according to any one of claims 2 to 5.
A deformation detection sensor for detecting the deformation state of the structure is provided.
The sensor position estimation unit is
Using the detection result of the deformation detection sensor, the positions of the plurality of magnetic sensors after displacement are estimated.
The magnetic source estimation device according to claim 1. The deformation detection sensor includes a strain sensor.
The sensor position estimation unit is
Using the amount of strain detected by the strain sensor, the positions of the plurality of magnetic sensors after displacement are estimated.
The magnetic source estimation device according to claim 7. The strain sensor has an elastic film shape.
The magnetic source estimation device according to claim 8. The strain sensor is built in the structure and integrally molded.
The magnetic source estimation device according to claim 9. The elastic modulus of the strain sensor is lower than the elastic modulus of the structure.
The magnetic source estimation device according to claim 9 or 10. The plurality of magnetic sensors and the deformation detection sensor are installed at different positions when the structure is viewed in a direction orthogonal to the outer surface.
The magnetic source estimation device according to any one of claims 7 to 11. The magnetic source estimation unit is
Using the magnetic charge measured by the plurality of magnetic sensors, the magnetic charge generated by the magnetic source is estimated.
The magnetic source estimation device according to any one of claims 1 to 12. A step to measure the magnetism generated by a magnetic source with multiple magnetic sensors installed in a deformable structure,
A step of estimating the position of the plurality of magnetic sensors after displacement due to the deformation of the structure, and
A step of estimating the position of the magnetic source using the estimated positions of the plurality of magnetic sensors after displacement and the measured magnetism.
A method for estimating a magnetic source.

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