KR102562559B1 - Electronic Device and And Control Method Thereof - Google Patents

Abstract

The present invention relates to a technique for estimating the position and posture of a moving object using a magnetic field.
The present invention provides a magnetic field sensor for measuring magnetic fields having different frequencies generated by a plurality of electromagnets, a storage unit for storing a magnetic field map for a moving area of an electronic device, and a magnetic field map based on values measured by the magnetic field sensor and the magnetic field map. It includes a control unit for estimating the location and posture of the electronic device.
In the case of the present invention, since the alternating magnetic field generated from the magnetic body is measured and restored to estimate the position and posture of the mobile body, there is an effect of more accurately estimating the three-dimensional position and posture of the mobile body unaffected by the surrounding magnetic field environment.

Description

Electronic Device and Control Method Thereof

The present invention relates to an electronic device and a control method thereof, and more particularly, to a technology for estimating the position and attitude of a moving object within a certain space using a magnetic field sensor, an inertial sensor, and a magnetic field map.

In modern society, technology for estimating the position of a person or a specific object is widely used in various fields. This is called Location-Based Service (LBS). Representatively, the GPS (Global Positioning System) method using artificial satellites or mobile communication base stations to cover a wide area and the RTLS (Real Time Location System) method used inside buildings or in limited spaces are used. system), etc. In the case of the RTLS method, Zigbee communication, RFID (Radio-Frequency Identification), Bluetooth, and Wi-Fi methods are used.

In the case of an inertial navigation system (Pure System) that uses an inertial sensor (IMU, Inertial Measurement Unit) to estimate the position of a moving object, the angular velocity and acceleration signals output using a gyro and accelerometer are converted into coordinates and then time-integrated to determine the position of the moving object. Determine posture and position. Therefore, in the case of such an inertial sensor-based, the output integral value has a disadvantage in that the position of the moving object cannot be accurately estimated because errors are accumulated over time due to bias included in the measurement signal and irregular behavior components of the moving object.

In addition, a technique for estimating a position using the earth's magnetic field is also widely used. In the case of estimating a position using the earth's magnetic field, unlike electromagnetic waves, it has the advantage of being virtually unaffected by most substances and can estimate the position. Therefore, it can be measured underwater, and is widely used as an important navigation means in an environment where radio navigation such as GPS is impossible, for example, in a submarine in the sea.

However, in the case of position estimation using a magnetic field, as described above, if there is a material that is not affected by other materials, but ferromagnetic materials such as iron, nickel, and cobalt exist around the moving object, these materials block the magnetic field or Distortion may occur. That is, an error is generated by affecting the measurement value of a 3-axis MEMS (Micro Electro Mechanical System) magnetic sensor that measures magnetic fields of objects having magnetic properties. The error generated at this time is offset shift (Hard Iron Effect) and proportional constant error (Soft Iron Effect), which are errors of the magnetic sensor itself. Therefore, in the case of a position estimation system using a peripheral magnetic field, many considerations are required in configuration and component arrangement.

The present invention was developed to solve the above-mentioned problems, and its purpose is to more accurately estimate the three-dimensional position and attitude of a moving object without being restricted by the surrounding magnetic field environment.

A magnetic material may cause a problem of blocking or distorting a magnetic field, but may also actively generate an alternating magnetic field. Therefore, in the case of the present invention, since the alternating magnetic field generated from the magnetic body is measured and restored to estimate the position and posture of the mobile body, it is possible to more accurately estimate the three-dimensional position and posture of the mobile body unaffected by the surrounding magnetic field environment.

In an electronic device according to an embodiment of the present invention, in an electronic device for estimating the position and posture of a moving object, a magnetic field sensor for measuring magnetic fields having different frequencies generated by a plurality of electromagnets and a magnetic field for a moving area of the moving object It may include a storage unit for storing a map, and a control unit for estimating the position and attitude of the mobile body based on the values measured by the magnetic field sensor and the magnetic field map.

In addition, the magnetic field sensor may measure magnetic fields having different frequencies generated from the plurality of electromagnets using frequency division multiple access (FDMA).

In addition, the magnetic field sensor may set a frequency that is twice or more of the largest frequency among frequencies generated by the plurality of electromagnets as a sampling frequency of the magnetic field sensor.

In addition, the control unit is a Kalman filter, an extended Kalman filter (EKF), an unscented Kalman filter (UKF), an information filter, a histogram filter, The position and posture of the moving object may be estimated using any one of Markov position recognition methods.

In addition, the control unit may further include a restoration unit that restores each magnetic field vector generated from the plurality of electromagnets based on the values measured by the magnetic field sensor.

In addition, the control unit calculates a vector for the position and attitude of the moving object based on the restored magnetic field vector and a value measured by the magnetic field sensor, and compares the vector with the magnetic field map to estimate the position and attitude of the moving object. Wealth may be further included.

In addition, the estimator may compare the calculated position and attitude vector of the moving object with the vector of the magnetic field map, and estimate a point having the smallest difference as the position and attitude of the moving object.

In addition, the electronic device according to an embodiment of the present invention may further include a display unit that displays information on the estimated location and posture of the moving object on a screen.

In addition, the electronic device according to an embodiment of the present invention may further include a communication unit that transmits information about the estimated position and attitude of the moving object to an external device.

In addition, the electronic device according to an embodiment of the present invention may further include an inertial measurement unit (IMU) for measuring acceleration and angular velocity values of the moving object.

In addition, the control unit may further include a correction unit for correcting the estimated position and attitude of the moving object using the values measured by the inertial sensor.

Also, the correction unit may calculate a tilt error of the moving object based on the values measured by the inertial sensor, and correct the estimated position and attitude of the moving object using the tilt error.

Also, the tilt error may include a pitch of the movable body, a roll of the movable body, and a yaw of the movable body.

A control method of an electronic device according to an embodiment of the present invention is a method of estimating the position and posture of a moving body, comprising the steps of measuring magnetic fields having different frequencies generated in a plurality of electromagnets and in a moving area of the moving body. The method may include obtaining a magnetic field map for the object and estimating a position and attitude of the moving object based on the values measured by the magnetic field sensor and the magnetic field map.

In addition, the measuring of the magnetic field may further include measuring magnetic fields having different frequencies generated from the plurality of electromagnets using frequency division multiple access (FDMA).

In addition, the measuring of the magnetic field may further include, as a sampling frequency of the magnetic field sensor, a frequency that is twice or more of the highest frequency among the frequencies generated by the plurality of electromagnets. there is.

In addition, the step of estimating the position and posture of the moving object includes a Kalman filter, an Extended Kalman filter (EKF), an Unscented Kalman filter (UKF), an information filter, and a hiss The method may further include estimating the position and attitude of the moving object using any one of a histogram filter and a Markov position recognition method.

In addition, estimating the position and posture of the moving body may further include restoring each magnetic field vector generated from the plurality of electromagnets based on the values measured by the magnetic field sensor.

In addition, the step of estimating the position and attitude of the moving object calculates a vector for the position and attitude of the moving object based on the restored magnetic field vector and a value measured by the magnetic field sensor, and compares the vector with the magnetic field map to determine the position and attitude of the moving object. A step of estimating the position and posture of the may be further included.

In addition, the step of estimating the position and attitude of the moving object by comparing with the magnetic field map compares the calculated position and attitude vector of the moving object with the vector of the magnetic field map, and determines the position and attitude of the moving object at a point where the difference is smallest. A step of estimating the posture may be further included.

Also, the control method of an electronic device according to an embodiment of the present invention may further include displaying information on the estimated position and attitude of the moving object on a screen.

Also, the control method of an electronic device according to an embodiment of the present invention may further include transmitting information about the estimated location and posture of the moving object to an external device.

In addition, the method for controlling an electronic device according to an embodiment of the present invention may further include measuring acceleration values and angular velocity values of the moving object using an inertial measurement unit (IMU).

The method may further include correcting the estimated position and attitude of the movable body using the values measured by the inertial sensor.

The correcting may further include calculating a tilt error of the moving object based on values measured by the inertial sensor and correcting the estimated position and attitude of the moving object using the tilt error. can

Also, the tilt error may include a pitch of the movable body, a roll of the movable body, and a yaw of the movable body.

In the case of the present invention, by estimating the posture and position of a moving object using an alternating magnetic field generated from a magnetic body installed in a certain area where the moving object moves, the error of the sensor itself and the influence of the surrounding magnetic field, which the conventional position estimation system using a magnetic field had, have It is possible to overcome the disadvantages of receiving , and more accurately estimate the position and posture of a moving object.

1 is a block diagram showing an internal configuration of an electronic device according to an embodiment of the present invention.
Figure 2 (a) shows the state in which lines of magnetic force are emitted from two points (X, Y) according to an embodiment of the present invention, Figure 2 (b) shows the strength of the lines of magnetic force attenuation at two points (X, Y) This is a drawing showing what it would look like.
3 is a view showing the overlapping of electromagnetic force lines emitted from two points (X, Y).
4 is a diagram showing a state in which a secondary position of a moving object is estimated using a magnetic force vector according to an embodiment of the present invention.
5 is a flowchart illustrating a control method of an electronic device according to an embodiment of the present invention.
6 is a block diagram showing the internal configuration of an electronic device according to another embodiment of the present invention.
7 is a flowchart illustrating a control method of an electronic device according to another embodiment of the present invention.
8 is a diagram illustrating a state in which a tertiary position of a moving object is estimated using a magnetic force vector according to an embodiment of the present invention.
9 is a view showing an experimental model using four electromagnets to prove the effect of the present invention.
FIG. 10 is a diagram showing an actual moving distance and an estimated distance of a moving object according to the experiment of FIG. 9 .
FIG. 11(a) is a diagram showing the estimated change in altitude of the moving object according to the experiment of FIG. 9, and FIG. 11(b) is a diagram showing the trajectory rotation speed of the estimated moving object according to the experiment of FIG.
FIG. 12 is a diagram illustrating the movement of a yaw corresponding to the vertical posture of the mobile body according to the experiment of FIG. 9 .

The configurations shown in the embodiments and drawings described in this specification are preferred examples of the disclosed invention, and there may be various modified examples that can replace the embodiments and drawings in this specification at the time of filing of the present application.

In addition, the same reference numerals or numerals presented in each drawing in this specification indicate parts or components that perform substantially the same function.

In addition, terms used in this specification are used to describe embodiments, and are not intended to limit and/or limit the disclosed invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

In this specification, terms such as "include", "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or the existence or addition of more other features, numbers, steps, operations, components, parts, or combinations thereof is not excluded in advance.

In addition, terms including ordinal numbers such as “first” and “second” used herein may be used to describe various components, but the components are not limited by the terms, and the terms It is used only for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element, without departing from the scope of the present invention. The term "and/or" includes any combination of a plurality of related listed items or any of a plurality of related listed items.

Hereinafter, problems of the prior art for estimating the position of a moving object using a magnetic field will be investigated, and features of the present invention will be studied in detail through the following drawings.

In the case of conventional technology for estimating the position of a moving object using the Earth's magnetic field, the magnetic field has characteristics that are hardly affected by most substances, unlike electromagnetic waves, so that it can be measured underwater differently from other electromagnetic waves. Therefore, it is widely used as an important navigation method in an environment where radio navigation such as GPS is impossible, for example, a submarine in the sea.

However, in the case of position estimation using the Earth's magnetic field, if there are materials such as iron, nickel, and cobalt, which are ferromagnetic materials, around the moving object, although there are characteristics that are not affected by other materials, these materials block or distort the magnetic field. Problems can arise.

In other words, objects with magnetic properties may affect the measured values of the 3-axis MEMS (Micro Electro Mechanical System) magnetic sensor that measures the magnetic field, causing errors, and the errors generated at this time are offset transitions, which are errors in the magnetic sensor itself. (Hard Iron Effect) and Proportion Constant Error (Soft Iron Effect).

In the case of estimating a position using a magnetic sensor, due to its characteristics, an offset shift (Hard Iron Effect) error occurs more than a proportional constant error (Sort Iron Effect).

However, since the present invention estimates the position and attitude of a moving object using an alternating magnetic field, there is an advantage in fundamentally solving the offset shift error described above.

That is, in the case of an offset shift error, a part disposed around the sensor or the sensor itself is magnetized in a specific direction. The magnetization of a magnetic body basically has a fixed magnetic field property and cannot have a frequency property, so the offset transition No error occurs.

Even if a magnetic field with a frequency property is generated from a component such as a processor or an oscillator, it is very unlikely that the frequency and phase difference match the signal of the AC magnetic field to be used, and even if it matches the signal of the AC magnetic field, the magnitude very small and can be ignored.

For these reasons, an offset shift error does not occur when estimating the position of a moving object using an alternating magnetic field. Therefore, there is an advantage that there is no need for very periodic calibration.

In addition, in the case of estimating a position using an alternating magnetic field, a different advantage from the prior art is that a signal can be detected for each frequency by treating the magnetic field like an electromagnetic wave signal.

in other words. Since signals can be detected for each frequency, even if multiple alternating magnetic fields are in one space, their components can be detected individually, which has the advantage of generating more information than when using a single magnetic field. In addition, there is also a feature capable of performing positional navigation as well as positional navigation.

The configuration and operating principle of the present invention will be described in detail through the following drawings.

1 is a diagram showing the overall configuration of an electronic device according to an embodiment of the present invention.

1 is a block diagram showing an internal configuration of an electronic device 100 for estimating the position and attitude of a moving object to which the electronic device 100 is attached according to an embodiment of the present invention.

Referring to FIG. 1 , the present invention provides a magnetic field sensor 200 for measuring a magnetic field around a moving object to which an electronic device 100 is attached and a storage unit 300 storing information related to a magnetic field map 310 of a moving area of the moving object. ) and a control unit 400 for estimating the attitude and position of the moving object based on the measured magnetic field value 210 and the magnetic field map 310.

The magnetic field sensor 200 may measure the magnitude and direction of a magnetic field generated from an electromagnet installed in a certain area in which a moving object moves. In addition, the magnetic field sensor 200 may measure each magnetic field value for three axes including the X axis, Y axis, and Z axis of the moving object to be measured.

In the case of the magnetic field sensor 200, various types of sensors may be included depending on the purpose. A coil-type magnetic sensor using a voltage generated in proportion to the time change of the linkage magnetic flux, a solid-state magnetic sensor using the physical properties of a solid, a resonance-type magnetic sensor using the magnetic moment of an atomic nucleus or the level of atomic energy separated by a magnetic field, etc. may be included in this.

In the case of the present invention, since the position and posture of the moving object are estimated using the magnetic fields generated from a plurality of electromagnets installed in a certain area where the moving object moves, signals having frequencies interfere with each other when a plurality of electromagnets exist in a certain space. Problems can arise.

Therefore, in the case of the present invention, in order to solve this problem, the frequency generated by the electromagnet installed in a certain area in which the moving object moves is different from each other to prevent the problem of interference between frequencies. If the frequencies are different from each other, even if several electromagnets transmit different magnetic fields within a certain space, interference between magnetic fields does not occur.

Therefore, in the case of position estimation using an alternating magnetic field, as in the present invention, since the magnetic field is treated like an electromagnetic wave signal and signal detection is possible for each frequency, even if a plurality of alternating magnetic fields are present in one space, their components can be separately detected. Because of this, more information can be generated than in the case of using a fixed magnetic field, and there is an advantage in that it can estimate not only the position of the moving object but also the attitude using this information.

Therefore, in the case of the magnetic field sensor 200, as described above, since magnetic fields having different frequencies generated from several electromagnets must be detected, the magnetic field can be detected using frequency division multiple access (FDMA).

Frequency division method (FDMA) refers to a method of separating different frequencies using the signal superposition principle. That is, after generating and multiplying a sin wave signal of each frequency having an amplitude of 1 by the received superposition signal, the multiplied values are integrated. By integrating the multiplied values, a value directly related to the amplitude of each signal before superposition is calculated, and the amplitude of each signal can be obtained using the relationship.

The frequency division method has the advantage of being able to continuously use information of several magnetic field vectors in one space, unlike Time Division Multiple Access (TDMA), which separates and measures a range of time.

In addition, in order to digitally measure the alternating magnetic field using the frequency division method described above, the sampling frequency of the magnetic field sensor 200 should be more than twice the largest frequency among the frequencies of the magnetic field emitted by the electromagnets. do.

Since the maximum frequency of the alternating magnetic field used in the experiments to be described later is 70 Hz, a minimum sampling frequency of 140 Hz is required. However, this is the lowest value and further frequency selection is required to more precisely contain the frequency components of the signal.

Therefore, the magnetic field sensor 200 of the present invention is used by selecting a frequency at least twice as large as the frequency generated by the electromagnets installed in the space to be measured as the sampling frequency. In the case of the experiment to be described later, a frequency of 1 kHz was selected and used as a sampling frequency.

The storage unit 300 may serve to store information related to the magnetic field map 310 .

Here, the magnetic field map 310 refers to a map in which magnetic field values measured in a range in which a moving object can move are stored. Since a plurality of electromagnets are installed in the moving area, the plurality of electromagnets generate alternating magnetic fields at different frequencies. Accordingly, the magnetic field map 310 refers to a map including information about the magnitude and direction of a magnetic field generated by alternating magnetic fields within a moving object range. A space in which such a movable body can move may be an enclosed space such as a washing machine, and may correspond to a room of about several meters.

In this case, the plurality of locations on the map may be locations maintained at predetermined intervals, and in some cases may be locations where a magnetic field value can be measured or locations composed only of locations that a mobile body can reach.

Also, the plurality of positions may be positions on a 3-dimensional space rather than simply on a 2-dimensional plane.

In general, if only one electromagnet exists in a certain space, a one-dimensional position can be calculated with the measured magnetic field vector, and if two electromagnets are used, a two-dimensional position can be calculated. In addition, if three electromagnets are used, the 3D position can be calculated, and if more electromagnets are used, the 3D position can be more accurately calculated.

Therefore, in order to estimate the 3D position of the moving object, at least three electromagnets are required, and a magnetic field map 310 storing magnetic values in a specific space in which at least three electromagnets are installed is required.

The storage unit 300 may also store a plurality of magnetic field maps to perform position estimation in a plurality of regions.

The control unit 400 may estimate the position and posture of the moving object using the magnetic field value 210 measured by the magnetic field sensor 200 and the magnetic field map 310 stored in the storage unit 300 .

More specifically, the control unit 400 restores the isomagnetic force vector in space for each magnetic field generated from a plurality of electromagnets installed in the space to be measured based on the magnetic field value 210 measured by the magnetic field sensor 200. It may further include an estimator 420 that estimates the current position and attitude of the moving object by calculating vector information on the current position of the moving object using the unit 410 and the restored vector and comparing it with the magnetic field map 310. there is.

The control unit 400 is an algorithm for estimating the position of a moving object, a Kalman filter, an Extended Kalman filter (EKF), an unscented Kalman filter (UKF), and an information filter The position may be estimated using at least one of , a histogram filter, and a Markov position recognition method.

FIG. 2 is a view showing the restored alternating magnetic field generated by electromagnets A and B in a certain space by the restoration unit 410. FIG. 2(a) shows the equal magnetic force vector of the alternating magnetic field, (b) shows the magnitude of the magnetic field vector attenuated from the centers A and B of the electromagnet.

Referring to FIG. 2, it can be seen that the direction of the magnetic force line is parallel to the direction of the magnetic field, comes out of the N pole and heads to the S pole, and the magnetic field has a closed curve shape in which the magnetic field is absorbed again as much as it is emitted from the electromagnet.

The density of the lines of magnetic force represents the strength of the magnetic field, and the closer the lines of magnetic force are, the stronger the magnetic field. In general, the spacing of the lines of magnetic force is close at both magnetic poles of a magnet, and the density of the lines of magnetic force decreases as they gradually move away from the magnetic poles.

Therefore, referring to FIG. 2, it can be seen that the density of the magnetic field is high in the vicinity of A and B, which generate the magnetic field, so that the intensity of the magnetic field is high, and the intensity of the magnetic field decreases as the distance from A and B increases. 310) can be stored.

FIG. 3(a) is a diagram showing equal magnetic force vectors of two overlapping alternating magnetic fields in a certain space, and FIG. 3(b) is a diagram showing the strength of two overlapping alternating magnetic fields.

Since a plurality of electromagnets are required to more accurately estimate the position of a moving object, when a plurality of electromagnets are installed as shown in FIG. 3 (a), two magnetic force vectors having different frequencies appear.

However, since the frequencies of the two alternating magnetic fields are different from each other, interference does not occur even when the vectors of the two alternating magnetic fields overlap in space. Therefore, an independent magnetic field vector can be restored.

As shown in (b) of FIG. 3, since no interference occurs, the two alternating magnetic fields can be independently restored, and the strength of the magnetic fields also independently attenuates as the distance from the center of the magnetic field increases.

4 is a diagram illustrating a state in which a position and attitude of a moving object are estimated using a magnetic force vector according to an embodiment of the present invention.

As shown in FIG. 4, one or more electromagnets are installed in a space in which the location of a moving object is to be estimated. In the case of FIG. 4 , two-dimensional coordinate measurement using two electromagnets is shown, but three electromagnets may be installed in the case of three-dimensional coordinate measurement.

That is, in the case of FIG. 4, there are two electromagnets (A and B), each electromagnet generates an alternating magnetic field having a different frequency, and the magnetic field sensor 200 of the present invention has a magnetic field generated by the electromagnets A and B. measure the size and position of

In addition, the restoration unit 410 restores the equal magnetic force curves M1 and M2, respectively, as shown in FIG. 4 based on the measured magnetic field value 210, and uses the restored equal magnetic force curves M1 and M2 to determine the current position of the moving object. to estimate

That is, as shown in FIG. 4, the estimator 420 obtains the intersection of the curves of the two isomagnetic lines of force, and based on this, it is possible to estimate the coordinate point in space by matching the size of the vector.

If, in case of estimating a position in a 3-dimensional space, the magnetic fields generated by the three electromagnets are measured, respectively, and three isomagnetic force curves M1 and M2. The location of the moving object can be estimated by restoring M3. Then, by obtaining the intersection of these three curved surfaces and performing matching on the magnitude of the magnetic field vector, the coordinate point on the space of the moving object can be obtained.

If the position and attitude of the moving object are estimated through the process described above, the estimator 420 calculates vector information for the estimated position and then compares it with information on the position stored in the magnetic field map 310 to calculate the vector information for the moving object. estimate the location of

That is, the estimator 420 compares spatial vector information already stored in the magnetic field map 310 based on the vector for the estimated location and details of the moving object, and then estimates the location with the smallest difference as the current location. . The reason why the position with the smallest difference is estimated as the current position is that the current moving object has the highest probability of being at that position.

5 is a flowchart illustrating a control method of an electronic device according to an embodiment of the present invention.

First, the electronic device 100 attached to the moving object measures the magnetic field around the moving object using the magnetic field sensor 200 (S100).

Since electromagnets are already installed in the moving environment, each electromagnet will emit alternating magnetic fields with different frequencies. Therefore, the magnetic field sensor 200 can measure the magnitude and direction of this alternating magnetic field.

Since the position and attitude of the moving object are estimated based on the measured magnetic field, not only the size of the magnetic field but also the direction (or position) of the magnetic field along the X, Y, and Z axes can be measured.

When the magnitude and direction of the magnetic field are measured, vectors for each alternating magnetic field generated by the electromagnet are restored based on the measured magnetic field (S200).

Since each electromagnet transmits an AC magnetic field having a different frequency, and the magnetic field sensor 200 measures the magnetic field using a frequency division method, vectors for each independent AC magnetic field can be restored. The appearance of the restored alternating magnetic field vector is shown in FIGS. 2 and 3 as seen above.

If the vector for the alternating magnetic field is restored, vector information on the position and posture of the moving object is calculated based on this. (S300)

If the vectors are restored based on the alternating magnetic fields emitted from the two electromagnets, the position of the 2D moving object can be estimated. If the vectors are restored based on the alternating magnetic fields emitted from the three electromagnets, the position and attitude of the 3D moving object can be estimated. can do. When four or more electromagnets are added, it is possible to more accurately estimate the position and posture of the moving body of the three-dimensional moving body.

If vector information about the location and details of the moving object is calculated, based on this, the position and attitude of the moving object are estimated by comparing with the magnetic field map (S400).

That is, vector information about the location and details of the moving object is compared with the information on the magnetic field for each location stored in the magnetic field map, and the area with the smallest difference in the vector is estimated as the location of the moving object, and based on this, the posture of the moving object is estimated. to estimate

6 is a block diagram showing an internal configuration of an electronic device according to another embodiment of the present invention.

Descriptions of the magnetic field sensor 200, the storage unit 300, the restoration unit 410, and the estimation unit 420 are omitted because they are the same as those described in FIG. 1, and other features will be described below.

The inertial sensor 500 may measure the acceleration value and the angular velocity value of the moving object using an inertia measurement unit, and the correction unit 420 may determine the position and posture of the moving object estimated by the estimation unit 410. It can play a role of correcting the information more accurately by using the acceleration value 510 and the angular velocity value 520 measured by the inertial sensor 500.

The inertial sensor 500 refers to a sensor capable of measuring various motion information such as acceleration, speed direction, and distance of a moving object after detecting the inertial force of the moving object, and measures the inertial force acting on the inertial body by the acceleration applied to the object. It works on the detection principle.

The inertial sensor 500 can be classified into an accelerometer and a gyros cope, and can be operated in various ways such as a method using a laser and a non-mechanical method.

Accordingly, the inertial sensor 500 may include an inertial sensor using an inertial input, for example, an acceleration sensor, an inertial sensor, a geomagnetic sensor, and the like, and the acceleration sensor may include a piezoelectric acceleration sensor, a capacitive acceleration sensor, and a strain gauge acceleration sensor It may include at least any one of the like.

When the position of the moving object is estimated using the magnetic field sensor 200, if the position of the moving object is tilted at the time when the magnetic field sensor 200 measures the magnetic field value 210, the measured magnetic field value has a tilt error can happen

Tilt error is an error in the magnetic field value 210 caused by the tilt of the magnetic field sensor. At this time, the tilt error can be expressed as the degree of rotation about each of the three axes as the central axis, and the three axes The degree of rotation about each of them as a central axis may be expressed as pitch, roll, and yaw, respectively.

That is, pitch refers to the degree of rotation around an axis in a horizontal plane perpendicular to the direction of movement, and roll refers to the degree of rotation around an axis in a horizontal plane parallel to the direction of movement. And Yaw refers to the degree of rotation around an axis in the vertical plane perpendicular to the direction of movement.

In addition, since the control unit 400 of the present invention estimates the position of a moving object using an estimation algorithm such as a particle filter, if an error occurs in an intermediate result value for position estimation during the algorithm, the final position estimation result value becomes very inaccurate. Problems can arise. This is because a position estimation algorithm such as a particle filter performs a next cycle based on a position estimated in a previous cycle and calculates a final position result value by repeating the cycle.

Therefore, due to the two problems described above, the value of the magnetic field 210 estimated by the magnetic field sensor 200 may be different from the actual value, and accordingly, the estimated position and attitude of the moving object may also result in slightly different results from the actual result. can

Therefore, the correction unit 430 more accurately corrects the position and posture of the moving object estimated by the estimation unit 420 using the acceleration and angular velocity values measured by the inertial sensor 500 to prevent the above-described problems. can play a role

That is, the correction unit 430 obtains the speed information of the moving object using the acceleration value 510 obtained from the inertial sensor 500 and obtains the azimuth information of the moving object using the angular velocity value 520 obtained using a magnetic sensor or the like. The moving position and direction of the moving object may be determined by calculating information on the moving distance and direction from the initial position of the moving object to the next position. In addition, the position of the moving object estimated by the estimator 420 can be more accurately corrected using this information.

More specifically, the correction unit 430 includes magnetic field values 210, acceleration values 510, and angular velocity values 520 for the X-axis, Y-axis, and Z-axis obtained from the magnetic field sensor 200 and the inertial sensor 500. ) is used to calculate the tilt error of the moving body. As described above, the tilt error may be expressed by pitch, roll, and yaw of the moving body.

Further, the correction unit 420 may more accurately estimate the position and attitude of the moving object by calibrating the measured magnetic field value 210 based on the offset-calculated tilt error.

The communication unit 600 may serve to transmit information about the position and posture of the moving object estimated by the control unit 400 to an external device.

Here, the external device may be a user's mobile terminal device using a mobile body, and the display unit 700 may correspond thereto.

Therefore, the communication unit 600 is a module for communicating with an external device, wireless Internet technologies include WLAN (Wireless LAN), Wi-Fi, WiBro (Wireless Broadband), WiMAX (World Interoperability for Microwave Access) , modules such as HSPDA (High Speed Downlink Packet Access) may be installed, and as short-range communication technologies, Bluetooth, Zigbee, RFID (Radio Frequency Identification), infrared communication (IrDA: Infrated Data Association) , modules such as UWB (Ultra Wideband) communication can be installed.

The display unit 700 may play a role of displaying information on the position and attitude of the moving object estimated by the controller 400 on the screen. Accordingly, a liquid crystal display (LCD) may be used to express this, and other flat display panels may be used.

7 is a flowchart illustrating a control method of an electronic device according to another embodiment of the present invention.

The magnetic field sensor 200 and the inertial sensor 500 of the electronic device 100 attached to the moving object measure the magnetic field value 210 of the moving object area, the acceleration value 510, and the angular velocity value 520 of the moving object, respectively. (S1000, S1100)

And, if the magnetic field value 210 is measured, the alternating magnetic field generated by each electromagnet is restored based on this, and vector information about the position of the moving object is calculated based on this, and based on the magnetic field information about the position stored in the magnetic field map Estimate the position and posture of the moving object. (S1200 ~ S1400)

Then, the estimated position and posture are corrected using the values of acceleration and angular velocity measured using the inertial sensor 500 (S1500).

As described above, the technique of correcting the estimated position and attitude using the acceleration value 510 and the angular velocity value 520 can calculate and correct the tilt error of the moving object.

If the information on the position and posture of the moving object is finally estimated, the information can be transmitted to an external device or displayed on the display unit 700 .

In the case of FIG. 7 , the corrected position and posture are expressed as being sent to the outside, but the position and posture of the moving object estimated according to FIG. 5 may be directly transmitted to the outside and to the display unit 700 .

FIG. 8 is a diagram showing a state in which the 3D position and attitude of a moving object are estimated according to FIG. 5 or FIG. 7 .

As described above, in order to know the three-dimensional position and posture, as shown in FIG. 8, at least three electromagnets (X, Y, and Z) generating alternating magnetic fields are required.

In the case of a three-dimensional constant magnetic force vector, a curved surface is formed, and it can be estimated that the moving body is located at the intersection of the three restored curved surfaces.

9 is a view schematically showing a model tested to prove the effect of the present invention, and FIGS. 10 to 12 are views expressing the results of the experiment in FIG.

Referring to FIG. 9, in this experiment, four electromagnets were used, and the frequencies of each electromagnet were set to 40 Hz, 50 Hz, 60 Hz, and 70 Hz differently. In addition, a small model car moved in a circle in the four electromagnets, and at this time, the position, altitude, and speed of the moving model car were estimated, and the result of actual movement was compared with the estimated value.

10 is a view showing the results of the horizontal position of the model car as a result of the experiment in FIG. 9 .

Referring to FIG. 10 , a circle drawn with a dotted line represents the moving range of the actual model car, and the other lines represent the estimated position of the moving object. As can be seen from FIG. 10, it can be seen that the actual moved position and the estimated position are not significantly different, and it can be seen that the estimated value does not tend to diverge at all during one rotation time.

11(a) is a diagram showing the estimated vertical position of the model car, and FIG. 11(b) is a diagram showing the estimated trajectory rotational speed of the model car.

In the case of (a) of FIG. 11, it can be seen that the estimated numerical value is relatively accurately estimated without diverging as shown in FIG. 10, and in the case of (b) of FIG. It can be seen that the and movement sections are clearly distinguished. It can be seen from the two graphs of FIG. 11 that position estimation is performed relatively accurately.

FIG. 12 is a view showing changes in yaw corresponding to the vertical posture of the model car as a result of the experiment in FIG. 9 .

Referring to FIG. 12, it can be seen that the yaw corresponding to the vertical posture has completely rotated the trajectory, and in the case of position estimation by the traditional inertial sensor, there is a tendency to diverge, but it can be seen that there is no such tendency there is. Through this, it can be seen that the present invention enables more accurate position estimation.

So far, the technology related to location recognition and map creation of the mobile robot corresponding to the present invention has been studied.

In the case of the present invention, since the position and posture of the moving object are estimated using a magnetic field, it can be used even in water where radio waves cannot penetrate. For example, it can be used for a cooling tower using a circulating flow water tank, a tidal power plant, an underwater probe, etc., and can be attached to laundry to accurately estimate the position of the laundry in the washing machine.

In addition, it can also be applied to cases where the body or object interferes with positioning by affecting radio wave radiation. For example, by attaching the present invention to human body motion capture or a person or object moving indoors, the position and posture of a person or object can be determined. can be accurately estimated.

In the case of the present invention, since the alternating magnetic field generated from the magnetic body is measured and restored to estimate the position and posture of the moving body, there is an effect of estimating the three-dimensional position and posture of the moving body more accurately without being affected by the surrounding magnetic field environment. . In addition, there is an effect of more accurately estimating a position by measuring a magnetic field using an inertial sensor.

100: electronic device 200: magnetic field sensor
210: magnetic field value 300: storage unit
310: magnetic field map 400: control unit
410: restoration unit 420: estimation unit
430: correction unit 500: inertial sensor
510: acceleration value 520: angular velocity value
600: communication unit 700: display unit

Claims (26)

In an electronic device for estimating the position and attitude of a moving object,
a magnetic field sensor for measuring magnetic fields having different frequencies generated by a plurality of electromagnets;
a storage unit storing a magnetic field map of the moving area of the mobile body;
A controller for estimating the position and attitude of the moving object based on the values measured by the magnetic field sensor and the magnetic field map;
The control unit,
Restoring each magnetic field vector and isomagnetic force line generated from the plurality of electromagnets based on the values measured by the magnetic field sensor,
Calculate a vector for the position and attitude of the moving object based on the magnitude of the magnetic field vector and the intersection of the equal magnetic force lines;
An electronic device for estimating a position and attitude of the moving object by comparing the calculated vector with the magnetic field map. According to claim 1,
The magnetic field sensor,
An electronic device for measuring magnetic fields having different frequencies generated from the plurality of electromagnets using frequency division multiple access (FDMA). According to claim 1,
The magnetic field sensor,
The electronic device of claim 1 , wherein a sampling frequency of the magnetic field sensor is a frequency that is twice or more of a frequency having a largest frequency among frequencies generated by the plurality of electromagnets. According to claim 1,
The control unit,
Kalman Filter, Extended Kalman filter (EKF), Unscented Kalman filter (UKF), Information filter, Histogram Filter, Markov position An electronic device for estimating the position and posture of the moving object using any one of the recognition methods. delete delete According to claim 1,
The control unit,
An electronic device that compares the calculated vector with the vector of the magnetic field map and estimates a point having the smallest difference as the position and attitude of the moving object. ◈Claim 8 was abandoned when the registration fee was paid.◈ According to claim 1,
The electronic device further comprising a display unit displaying information on the estimated position and posture of the moving object on a screen. According to claim 1,
The electronic device further comprising a communication unit that transmits information about the estimated position and attitude of the moving object to an external device. According to claim 1,
The electronic device further comprising an inertial sensor (IMU, Inertial Measurement Unit) for measuring an acceleration value and an angular velocity value of the moving object. According to claim 10
The control unit,
The electronic device further includes a correction unit for correcting the estimated position and posture of the moving object using the values measured by the inertial sensor. According to claim 11,
The correction unit,
An electronic device that calculates a tilt error of the moving object based on the values measured by the inertial sensor and corrects the estimated position and attitude of the moving object using the tilt error. According to claim 12,
The tilt error is
An electronic device comprising a pitch of the movable body, a roll of the movable body, and a yaw of the movable body. ◈Claim 14 was abandoned when the registration fee was paid.◈ A method for estimating the position and posture of a moving object,
Measuring magnetic fields having different frequencies generated in a plurality of electromagnets;
obtaining a magnetic field map of a moving area of the moving body;
Estimating the position and attitude of the mobile body based on the measured values and the magnetic field map;
The step of estimating the position and attitude of the mobile body,
restoring magnetic field vectors and isomagnetic lines of force generated from the plurality of electromagnets based on the measured magnetic field values;
calculating a vector for a position and posture of the moving object based on the magnitude of the magnetic field vector and the intersection of the equal magnetic force lines;
and estimating a position and posture of the moving object by comparing the calculated vector with the magnetic field map. ◈Claim 15 was abandoned when the registration fee was paid.◈ According to claim 14,
The step of measuring the magnetic field,
A control method of an electronic device comprising measuring magnetic fields having different frequencies generated from the plurality of electromagnets by using frequency division multiple access (FDMA). ◈Claim 16 was abandoned when the registration fee was paid.◈ According to claim 14,
The step of measuring the magnetic field,
A control method of an electronic device comprising the step of setting a frequency that is twice or more of the largest frequency among frequencies generated by the plurality of electromagnets as a sampling frequency of the magnetic field measurement. ◈Claim 17 was abandoned when the registration fee was paid.◈ According to claim 14,
The step of estimating the position and attitude of the mobile body,
Kalman Filter, Extended Kalman filter (EKF), Unscented Kalman filter (UKF), Information filter, Histogram Filter, Markov position A control method of an electronic device comprising the step of estimating the position and posture of the moving object using one of the recognition methods. delete delete ◈Claim 20 was abandoned when the registration fee was paid.◈ According to claim 14,
The step of estimating the position and attitude of the mobile body,
The control method of the electronic device further comprising the step of comparing the calculated vector with the vector of the magnetic field map and estimating a point where the difference is smallest as the position and posture of the moving object. ◈Claim 21 was abandoned when the registration fee was paid.◈ According to claim 14,
The control method of the electronic device further comprising the step of displaying information on the position and posture of the estimated moving object on a screen. ◈Claim 22 was abandoned when the registration fee was paid.◈ According to claim 14,
The method of controlling an electronic device further comprising transmitting information about the estimated position and posture of the moving object to an external device. ◈Claim 23 was abandoned when the registration fee was paid.◈ According to claim 14,
The method of controlling an electronic device further comprising measuring acceleration values and angular velocity values of the moving object using an inertial measurement unit (IMU). ◈Claim 24 was abandoned when the registration fee was paid.◈ 24. The method of claim 23,
and correcting the estimated position and posture of the moving object using the values measured by the inertial sensor. ◈Claim 25 was abandoned when the registration fee was paid.◈ 25. The method of claim 24,
The correcting step is
Calculating a tilt error of the moving object based on the values measured by the inertial sensor and correcting the estimated position and posture of the moving object using the tilt error. ◈Claim 26 was abandoned upon payment of the setup registration fee.◈ According to claim 25,
The tilt error is
A control method of an electronic device comprising a pitch of the movable body, a roll of the movable body, and a yaw of the movable body.

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