Distance estimation device, antenna device, power supply system, power supply device, and power supply method

Abstract

To provide a distance estimation device that can estimate in real time the distance between a power reception device and a power supply device.SOLUTION: A distance estimation device includes a position derivation unit that replaces a first position of a marker included in an image acquired through a fisheye lens with respect to an image acquisition unit with a second position at the polar coordinates on a first plane including a first axis and a second axis; and an elevation angle acquisition unit that acquires a first angle of elevation of a position obtained by projecting the first position on a second plane including the first axis and a third axis based on the second position with respect to the third axis in the second plane, and the distance estimation device estimates the first axial direction between the image acquisition unit and the marker based on the coordinates of an upper end of the marker included in the image determined from a second angle of elevation to the third axis of the upper end and an azimuth to the first axis, the coordinates of a lower end of the marker included in the image determined from a third angle of elevation to the third axis of the lower end and an azimuth to the first axis, and the length between the upper end and the lower end, and estimates the distance in the third axis direction between the image acquisition unit and the marker from the first angle of elevation and the first axial distance.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a distance estimation device, an antenna device, a power supply system, a power supply device, and a power supply method.

Background Art

[0002] Conventionally, there is a wireless power transmission device including: a beam transmission unit that transmits an energy beam for power supply to a wireless power reception device mounted on an aircraft; an information acquisition unit that acquires control information for increasing the power reception efficiency of the wireless power reception device; and a control unit that controls the energy beam based on the control information so as to increase the power reception efficiency of the wireless power reception device. It is described that an array antenna may be used as a transmission antenna (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when power is transmitted from a plurality of antenna elements of an array antenna and received by a wireless power reception device, when the wireless power reception device is mounted on an aircraft as in a conventional wireless power transmission device, there is a sufficient distance between the wireless power transmission device (power supply device) and the wireless power reception device (power reception device). For this reason, the angular difference between the plurality of antenna elements and the power reception device is negligible, and even when power is transmitted from the plurality of antenna elements to the same target, the reception phase shift is small when the power reception device receives power and hardly causes a problem.

[0005] However, when the distance between the power receiving device and the power feeding device is as short as about several meters, if power is transmitted from a plurality of antenna elements to the same target, when the power receiving device receives power, the difference in the angles from each antenna element to the power receiving device is large and the received phase shift becomes large, so that the combined received power may be reduced.

[0006] In order to solve such a problem, in order to adjust the phases of the power transmission signals transmitted from a plurality of antenna elements to align the received phases, it is desirable to know in real time the distance between the power receiving device and the power feeding device.

[0007] Accordingly, an object of the present invention is to provide a distance estimation device, an antenna device, a power feeding system, a power feeding device, and a power feeding method capable of estimating in real time the distance between a power receiving device and a power feeding device.

Means for Solving the Problems

[0008] The distance estimation device according to an embodiment of the present invention includes an image acquisition unit that acquires an image through a fisheye lens, a position derivation unit that converts a first position of a marker included in the image acquired by the image acquisition unit with respect to the image acquisition unit into a second position in polar coordinates on a first plane including a first axis and a second axis, an elevation angle acquisition unit that acquires a first elevation angle with respect to a third axis in the second plane of a projection position obtained by projecting the first position onto a second plane including the first axis and a third axis based on the second position, and a distance estimation unit that estimates a distance between the image acquisition unit and the marker. The distance estimation unit estimates a distance in the first axis direction between the image acquisition unit and the marker based on coordinates of an upper end portion of the marker included in the image obtained from a second elevation angle with respect to the third axis and an azimuth angle with respect to the first axis, coordinates of a lower end portion of the marker included in the image obtained from a third elevation angle with respect to the third axis and an azimuth angle with respect to the first axis, and a length between the upper end portion and the lower end portion, and estimates a distance in the third axis direction between the image acquisition unit and the marker based on the first elevation angle acquired by the elevation angle acquisition unit and the estimated distance in the first axis direction.

Advantages of the Invention

[0009] It is possible to provide a distance estimation device, an antenna device, a power supply system, a power supply device, and a power supply method that can estimate in real time the distance between a power receiving device and a power supply device.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Modes for Carrying Out the Invention

[0011] Hereinafter, embodiments to which the distance estimation device, the antenna device, the power supply system, the power supply device, and the power supply method of the present invention are applied will be described.

[0012] <Embodiment> FIG. 1 is a diagram showing a power supply device 100 according to an embodiment. The power supply device 100 includes an array antenna 110, a phase shifter 120, a microwave generation source 130, a camera 140, and a control device 150. The antenna device 100A according to the embodiment is obtained by removing the microwave generation source 130 from the power supply device 100.

[0013] Hereinafter, the description will be made using the XYZ coordinate system. The plan view means the XY plane view. Also, the X-axis is an example of the first axis, the Y-axis is an example of the second axis, and the Z-axis is an example of the third axis. Also, the XY plane is an example of the first plane, and the XZ plane is an example of the second plane.

[0014] The array antenna 110 is grouped into, for example, N sub-arrays 110A. The first (#1) to the Nth (#N) of the N sub-arrays 110A are shown. #1 to #N represent the coordinates of the N sub-arrays 110A in the X-axis direction. Here, N is an integer of 2 or more, and FIG. 1 shows a form in which N is an even number of 4 or more as an example. The N sub-arrays 110A are arranged in the X-axis direction (the first axis direction), and each sub-array 110A includes, for example, four antenna elements 111. Therefore, the array antenna 110 includes, for example, 4N antenna elements 111. Each array antenna 110 extends in the Y-axis direction (the second axis direction). The antenna element 111 is a rectangular patch antenna in plan view. The array antenna 110 may have a ground plate held at the ground potential on the -Z-axis direction side of the antenna element 111. As an example, the centers of the positions of the 4N antenna elements 111 coincide with the origin of the XYZ coordinate system. Also, the number of antenna elements 111 included in each sub-array 110A may be 2 or more, and they may be arranged two-dimensionally.

[0015] Hereinafter, in addition to FIG. 1, FIG. 2 will be used for explanation. FIG. 2 is a diagram showing the power supply device 100 of the embodiment. In FIG. 2, the configuration around the phase shifter 120 is shown in a simplified manner as in FIG. 1. In FIG. 2, the origin of the XYZ coordinate system is shifted for easy viewing of the drawing, but hereinafter, it will be described as if the origin of the XYZ coordinate system coincides with the center of the positions of the 4N antenna elements 111 as shown in FIG. 1. Also, in FIG. 2, for each sub-array 110A, one antenna element 111 adjacent to the -Y-axis side in the X-axis direction is shown. Further, FIG. 2 shows the components included in the control device 150, and the marker 50A and the power receiving device 50B. The marker 50A and the power receiving device 50B are fixed to the inner wall 51 of the tunnel as an example. The inner wall 51 of the tunnel is an example of a wall portion, and the inside of the tunnel is an example of a space where the marker 50A arranged along the inner wall 51 exists. The antenna device 100A and the power supply device 100 are mounted on a work vehicle as an example, and while traveling in the tunnel, detect the marker 50A attached to the inner wall 51 of the tunnel and perform power transmission toward the power receiving device 50B.

[0016] Also, in FIG. 2, the marker 50A exists in the direction of an angle θb from the Z-axis in the XZ plane view. In FIG. 2, for convenience of explanation, the XYZ coordinate system is shifted, but since the origin of the XYZ coordinate system coincides with the center of the positions of the 4N antenna elements 111, the angle θb is the angle formed by the straight line connecting the origin of the XYZ coordinate system and the marker 50A in the XZ plane and the Z-axis. The angle θb is shown as a positive value when it swings toward the +X-axis side when viewed from the +Y-axis direction side of the XZ plane, and the value when it swings toward the -X-axis side is shown as a negative value.

[0017] Here, the distance estimation device 100B of the embodiment includes a camera 140, an elevation angle acquisition unit 152, a position shift detection unit 153, and a distance estimation unit 154 of the control device 150, and is a device for estimating the distance between the camera 140 and the marker 50A. In FIG. 2, the camera 140, the elevation angle acquisition unit 152, the position shift detection unit 153, and the distance estimation unit 154 included in the distance estimation device 100B are marked with the symbol 100B in parentheses.

[0018] The power supply system of the embodiment includes an antenna device 100A, a microwave generation source 130, a marker 50A, and a power receiving device 50B, and is a system that transmits a power transmission signal composed of microwaves generated by the microwave generation source 130 from the antenna device 100A to the power receiving device 50B. The power supply system will be described later with reference to FIG. 10. Also, the method executed by the power supply device 100 to supply power to the power receiving device 50 is the power supply method of the embodiment.

[0019] N phase shifters 120 are provided corresponding to N sub-arrays 110A, and the N phase shifters 120 are respectively connected to the antenna elements 111 of the N sub-arrays 110A. The phase shifter 120 is an example of a phase adjustment unit that adjusts the phase and is an example of a phase shifter. Among each sub-array 110A, four antenna elements 111 are connected in parallel to one phase shifter 120.

[0020] Among each sub-array 110A, power transmission signals of the same phase are supplied to the four antenna elements 111. Also, the phases of the power transmission signals output by the N phase shifters 120 to the N sub-arrays 110A are different from each other. Therefore, the angle (elevation angle) of the beam formed by the radio waves radiated from the 4N antenna elements 111 can be controlled within the XZ plane.

[0021] The beam formed by the radio waves radiated from the 4N antenna elements 111 is synonymous with the beam output by the array antenna 110. Also, the beam output by the array antenna 110 is synonymous with the beam output by the antenna device 100A and the power supply device 100.

[0022] The microwave generation source 130 is connected to the N phase shifters 120 and supplies microwaves of a predetermined power. The microwave generation source 130 is an example of a radio wave generation source. The frequency of the microwaves is, for example, a frequency in the 920 MHz band. Here, a form in which the power supply device 100 includes the microwave generation source 130 is described, but it is not limited to microwaves, and any radio wave of a predetermined frequency may be used.

[0023] The camera 140 is disposed between the N / 2-th sub-array 110A and the N / 2 + 1-th sub-array 110A in the X-axis direction, and is disposed between the second antenna element 111 and the third antenna element 111 from the +Y-axis direction side among the four antenna elements 111 included in each sub-array in the Y-axis direction. The camera 140 has a fisheye lens 141 and a camera body 142. The camera 140 is an example of an image acquisition unit. In FIG. 2, the camera body 142 is shown divided into an imaging unit 142A and an image processing unit 142B.

[0024] The fisheye lens 141 is a lens that adopts an equidistant projection method. The position of the center of the fisheye lens 141 coincides with the center of the 4N antenna elements 111 and the origin of the XYZ coordinate system as an example. The camera body 142 is a part of the camera 140 other than the fisheye lens 141, and may be a camera including a CMOS (Complementary Metal Oxide Semiconductor) image sensor or an infrared camera.

[0025] The camera 140 acquires an image including the marker 50A through the fisheye lens 141 and outputs the image data to the control device 150. The marker 50A is attached to a power receiving device 50B having a power receiving antenna which is a target to be irradiated with the beams output from the antenna device 100A and the power supply device 100. The antenna device 100A and the power supply device 100 obtain the position of the marker 50A included in the image acquired by the camera 140 and irradiate the power receiving device 50B with a beam.

[0026] The camera body 142 has an imaging unit 142A and an image processing unit 142B. The imaging unit 142A includes an imaging element and is a part that acquires image data by performing imaging through the fisheye lens 141. The image processing unit 142B performs image processing such as binarization processing on the image data acquired by the imaging unit 142A and outputs a pixel index to the control device 150. The pixel index is an XY coordinate value (address) indicating the position of the marker 50A on the imaging screen.

[0027] In addition, the image processing unit 142B performs a process of obtaining the contour of the marker 50A, a process of obtaining the maximum contour, and a process of reading the coordinates of the upper and lower ends of the marker 50A, and outputs data representing the coordinates of the upper and lower ends of the marker 50A to the control device 150.

[0028] The process of obtaining the contour of the marker 50A is a process of extracting one or more contours based on the distribution of pixel indices obtained by binarizing the image data acquired by the imaging unit 142A.

[0029] The process of obtaining the maximum contour is a process of obtaining the largest contour from the one or more contours extracted based on the distribution of pixel indices (the maximum contour extraction process by counting the number of pixels within the contour). By obtaining the largest contour, the influence of noise and the like can be excluded.

[0030] The process of reading the coordinates of the upper and lower ends of the marker 50A is a process of reading the coordinates of the upper and lower ends from the largest contour obtained by the process of obtaining the maximum contour. The image processing unit 142B outputs the read coordinates of the upper and lower ends of the marker 50A to the control device 150.

[0031] The control device 150 includes a position derivation unit 151, an elevation angle acquisition unit 152, a position deviation detection unit 153, a distance estimation unit 154, a control unit 155, and a memory 156. The control device 150 is realized by a computer including a CPU (Central Processing Unit) and a memory. The position derivation unit 151, the elevation angle acquisition unit 152, the position deviation detection unit 153, the distance estimation unit 154, and the control unit 155 are shown as functional blocks of the functions of the program executed by the control device 150. Further, the memory 156 functionally represents the memory of the control device 150.

[0032] Here, the position derivation unit 151, elevation angle acquisition unit 152, position deviation detection unit 153, distance estimation unit 154, control unit 155, and memory 156 will be described with reference to FIG. 3 in addition to FIGS. 1 and 2. FIG. 3 is a diagram showing the polar coordinate system of the array antenna 110. FIG. 3 shows the sub-array 110A of the array antenna 110 in the power supply device 100, the antenna elements 111 included in each sub-array 110A, and the beam 115 output from the array antenna 110, and other components are omitted. Further, FIG. 3 shows the polar coordinate system on a plane 1 parallel to the XY plane. The plane 1 is the xy plane of the image data acquired by the imaging unit 142A and is equal to the xy plane used for the pixel index output from the image processing unit 142B. The x-axis and y-axis are parallel to the X-axis and Y-axis of the XYZ coordinates, respectively, and have the same direction.

[0033] Also, let the position of the marker 50A in the XYZ coordinate system be P1, the elevation angle of the line segment connecting the origin O and the position P1 be θ, and the azimuth angle be φ. The elevation angle is the angle with respect to the +Z-axis direction, the azimuth angle is the angle with respect to the +X-axis direction, and the clockwise direction is taken as the positive value in the plan view seen from the +Z-axis direction side. Also, let the elevation angle of the line segment connecting the position P1a, which is the projection of the position P1 onto the XZ plane, and the origin O be θa. The elevation angle θa is an angle approximately obtained by projecting the elevation angle θ onto the XZ plane when the position of the marker 50A is close to the XZ plane. Similar to the angle θb, the elevation angle θa is shown as a positive value when it swings to the +X-axis direction side when viewing the XZ plane from the +Y-axis direction side, and the value when it swings to the -X-axis direction side is shown as a negative value.

[0034] The position P1 is an example of the first position, and the position P1a is an example of the projection position. Also, the origin O is an example of the reference point of the XYZ coordinate system.

[0035] The antenna device 100A and the power feeding device 100 control the elevation angle of the beam 115 output by the array antenna 110 only within the XZ plane. This is because the array antenna 110 performs in-phase power feeding in the Y-axis direction, resulting in a fixed beam in the Y-axis direction and enabling the beam to be swung in the elevation angle direction with the Z-axis set to 0 degrees. It is assumed that the position of the power receiving device 50B is not significantly deviated from the XZ plane (for example, within about ±30 degrees with respect to the elevation angle with respect to the Z-axis in the YZ plane). For a power receiving device 50B in such a position, by controlling only the elevation angle of the beam 115 within the XZ plane, it is possible to efficiently irradiate the power receiving device 50B with the beam 115 while suppressing the scale of the control unit of the array antenna 110.

[0036] The position derivation unit 151 calculates the centroid of the image of the marker 50A based on the pixel index output from the image processing unit 142B. The pixel index output from the image processing unit 142B represents an equidistant projection image obtained through the fisheye lens 141. Through this image processing, the position P1 of the marker 50A included in the image acquired by the camera 140 with respect to the array antenna 110 is converted into the position P2 in polar coordinates on the plane 1. In this way, the position derivation unit 151 derives the position P2. The position P2 is the position of the centroid calculated by the position derivation unit 151. The position P2 is an example of the second position.

[0037] The position P2 is represented by the radial distance r from the origin O and the declination angle φ. The radial distance r is expressed as r = f L assuming the focal length of the fisheye lens 141 is f L and θ. The declination angle φ is the same as the azimuth angle φ. The position derivation unit 151 obtains r·cosφ obtained by mapping the radial distance r to the X-axis through the above-described image processing. The position derivation unit 151 outputs the data representing the position P2 to the elevation angle acquisition unit 152.

[0038] The elevation angle acquisition unit 152 divides the X coordinate (r·cosφ) of the mapped position P2a obtained by mapping the position P2 to the X-axis by the focal length f L of the fisheye lens 141 to obtain a value (r·cosφ / f Lis obtained (calculated) as the elevation angle θa. The reason why the elevation angle θa can be obtained in this way will be described later. The elevation angle acquisition unit 152 outputs the elevation angle θa to the distance estimation unit 154 and the control unit 155.

[0039] The position deviation detection unit 153 obtains the shape and centroid of the marker 50A based on the pixel index output from the image processing unit 142B, and detects the position deviation between the camera 140 and the marker 50A in the Y-axis direction based on the position of the centroid within the range where the marker 50A exists. As an example, since the position of the center of the fish-eye lens 141 coincides with the center of the 4N antenna elements 111 and the origin of the XYZ coordinate system, as an example, if the position of the centroid in the Y-axis direction when there is no position deviation between the camera 140 and the marker 50A is set to Y = 0. The position deviation detection unit 153 determines that there is no position deviation between the camera 140 and the marker 50A if the position of the centroid in the Y-axis direction within the obtained range where the marker 50A exists is Y = 0. Further, the position deviation detection unit 153 determines that a position deviation occurs between the camera 140 and the marker 50A if the position of the centroid in the Y-axis direction within the obtained range where the marker 50A exists is not Y = 0, and detects the position deviation. The position deviation detection unit 153 outputs the detection result to the distance estimation unit 154. Note that the position of the centroid may be obtained from the position derivation unit 151.

[0040] When the elevation angle θa calculated by the elevation angle acquisition unit 152 is zero degrees (0°), the distance estimation unit 154 estimates the distance from the center of the fish-eye lens 141 to the marker 50A based on the number of pixel indexes output from the image processing unit 142B of the camera 140. The fact that the elevation angle θa is 0° means that the marker 50A exists in front of the fish-eye lens 141 in the Z-axis direction (the centroid of the marker 50A exists on the Z-axis).

[0041] The distance estimation unit 154 estimates the facing distance r from the center of the fish-eye lens 141 to the marker 50A when the elevation angle θa is 0°. FD The fact that the elevation angle θa is 0° is an example of being included in a predetermined angle range including 0°. The facing distance r FDIt is the distance when the marker 50A faces the camera 140 on the Z axis.

[0042] For example, when the camera 140 and the marker 50A are separated at a plurality of distances on the Z axis, the number of a plurality of binarized pixel indexes acquired by the image processing unit 142B is stored in advance in the memory 156. Then, when the elevation angle θa is zero degrees (0 degrees), the distance estimation unit 154 counts the number of pixel indexes output from the image processing unit 142B of the camera 140, and compares it with a plurality of reference data corresponding to the plurality of facing distances r FD in the memory 156, and estimates the facing distance r FD from the center of the fisheye lens 141 to the marker 50A when the elevation angle θa is 0 degrees. Since the number of pixel indexes varies depending on the facing distance r FD , the facing distance r FD can be estimated based on the number of pixel indexes.

[0043] When pixel indexes are output from the image processing unit 142B of the camera 140 a plurality of times when the elevation angle θa is zero degrees (0 degrees), the facing distance r FD may be estimated based on the average of the number of a plurality of pixel indexes.

[0044] Also, since the fisheye lens 141 is used, when there is a positional deviation between the camera 140 and the marker 50A, the number of pixel indexes is smaller than when there is no positional deviation between the camera 140 and the marker 50A for the same facing distance r FD . Therefore, when the positional deviation detection unit 153 determines that there is a positional deviation between the camera 140 and the marker 50A in the Y-axis direction, the distance estimation unit 154 stores in advance in the memory 156 data representing the degree of change in the number of pixel indexes with respect to the positional deviation in the Y-axis direction, and uses the corrected number of pixel indexes according to the degree of positional deviation in the Y-axis direction to estimate the facing distance r FD .

[0045] In addition, when the elevation angle θa is included in a predetermined angle range including 0 degrees, the distance estimation unit 154 estimates the opposing distance r using the above-described estimation method. FD However, when the elevation angle θa is not included in the predetermined angle range including 0 degrees, the distance X and the opposing distance Z are estimated in real time using an estimation method different from the above. The distance X and the opposing distance Z are the X component and the Z component of the distance from the center of the fisheye lens 141 to the marker 50A. Estimating the distance X and the opposing distance Z in real time means that when the elevation angle θa is not included in the predetermined angle range including 0 degrees, the distance X and the opposing distance Z are estimated in real time according to the elevation angle θa at that time. The above-described opposing distance r FD can be estimated only when the elevation angle θa is zero degrees (0 degrees), whereas the distance X and the opposing distance Z can be estimated at various angles where the elevation angle θa is not included in the predetermined angle range including 0 degrees, so they can be estimated in real time. The method for estimating the distance X and the opposing distance Z will be described later with reference to FIG. 7.

[0046] The control unit 155 controls the phase shift amount (adjustment amount) in the phase shifter 120 so that the direction of the beam 115 radiated by the array antenna 110 becomes the elevation angle θa in the XZ plane. The elevation angle θa is acquired by the elevation angle acquisition unit 152. In addition, the control unit 155 performs output control of the microwave generation source 130, shooting control of the camera 140, and the like.

[0047] The control unit 155 specifically performs the control of the phase shift amount in the phase shifter 120 as follows. The control unit 155 reads out phase data corresponding to the opposing distance r estimated by the distance estimation unit 154 and the elevation angle θa acquired by the elevation angle acquisition unit 152 from the memory 156, and controls the phase shift amounts in the N phase shifters 120 based on the read phase data. The opposing distance r estimated by the distance estimation unit 154 FD is the opposing distance r estimated by the distance estimation unit 154 when the elevation angle θa is included in the predetermined angle range including 0 degrees and when the elevation angle θa is not included in the predetermined angle range including 0 degrees. FD That is. FD

[0048] Here, for the power receiving antenna of the power receiving device to receive power efficiently, it is ideal that the phases of the power transmission signals when the power receiving antenna of the power receiving device receives power from the N sub-arrays 110A are equal. By the way, the antenna device 100A and the power feeding device 100 transmit a power transmission signal to a power receiving device 50B located at a short distance of about 3 m to about 7 m, for example, from the array antenna 110. When transmitting power to the power receiving device 50B attached to the inner wall 51 of the tunnel, in a state where the angle θb is 0 degrees, the distance from the array antenna 110 to the power receiving device 50B is about 3 m to about 5 m.

[0049] Since such short-distance power transmission is assumed, the relative difference in the distances from each of the N sub-arrays 110A to the power receiving antenna of the power receiving device is relatively large. When the N sub-arrays 110A transmit power to the same target, the phases of the power transmission signals received by the power receiving antenna of the power receiving device from the N sub-arrays 110A do not align, and the power receiving device 50B cannot receive power efficiently. The difference in the distances from each of the N sub-arrays 110A to the power receiving antenna of the power receiving device varies depending on the angle θb and the distance in the Z-axis direction from the N sub-arrays 110A to the power receiving antenna of the power receiving device.

[0050] Therefore, the antenna device 100A and the power feeding device 100 use phase data for adjusting the phases when each of the N sub-arrays 110A transmits power so that the phases of the power transmission signals received by the power receiving antenna of the power receiving device from the N sub-arrays 110A align. The phase data represents the amount of phase shift (adjustment amount). Here, as an example, assuming that power transmission is performed when the elevation angle θa changes from +70 degrees to -70 degrees as the antenna device 100A and the power feeding device 100 move, a plurality of sets of phase data for adjusting the amount of phase shift of the N sub-arrays 110A in 1-degree increments are prepared. Each phase data includes the amounts of phase shift of N phases set in N phase shifters 120 respectively connected to the N sub-arrays 110A corresponding to a certain elevation angle θa. 141 sets of such phase data were prepared in 1-degree increments for the range from +70 degrees to -70 degrees of the elevation angle θa, for a certain opposing distance r FDIt is phase data for a plurality of sets regarding FD In order to make it possible to adjust the phase shift amounts of the N sub-arrays 110A according to each of the plurality of opposing distances r FD prepare a plurality of sets of phase data for as many opposing distances r FD . Since the phase data is data created based on the angle θb, FIG. 2 shows a plurality of sets of phase data ψ3(θb) to ψ7(θb) using θb. The control unit 155 may use a plurality of sets of phase data for the angle θb equal to the elevation angle θa. Also, each of the phase data ψ3(θb) to ψ7(θb) has shift amounts θs#1 to θs#N corresponding to the coordinates (#1 to #N) of the N sub-arrays 110A. For example, among the shift amounts θs#1 to θs#N included in the phase data ψ3(θb), the shift amount θs#1 is used for the antenna element 111 of the sub-array 110A at coordinate #1, and the shift amount θs#N is used for the antenna element 111 of the sub-array 110A at coordinate #N. Hereinafter, when not distinguishing the shift amounts θs#1 to θs#N, they are referred to as the shift amount θs.

[0051] The control unit 155 uses a plurality of sets of phase data corresponding to the opposing distance r FD estimated by the distance estimation unit 154, and uses the phase data for the angle θb equal to the elevation angle θa obtained by the elevation angle acquisition unit 152 from among the plurality of sets of phase data, to control the phase shift amounts in the N phase shifters 120.

[0052] Here, the control unit 155 uses a plurality of sets of phase data corresponding to the opposing distance r FD estimated by the distance estimation unit 154, and uses the phase data for the angle θb equal to the elevation angle θa obtained by the elevation angle acquisition unit 152 from among the plurality of sets of phase data, to control the phase shift amounts in the N phase shifters 120.

[0053] The memory 156 is an example of a storage unit, and stores programs executed by the position derivation unit 151, the elevation angle acquisition unit 152, and the control unit 155 during processing, data used in association with the execution of the programs, data generated by the execution of the programs, and image data acquired by the camera 140, etc. Further, the memory 156 stores a plurality of sets of phase data for each of a plurality of opposing distances r FD For each of the plurality of opposing distances r, such as 3m, 4m, ···, 7m, five types of opposing distances r FD stores 141 sets of phase data at 1-degree intervals for the range where the elevation angle θa is from +70 degrees to -70 degrees. Further, the memory 156 stores length data representing the length between the upper end and the lower end of the marker 50A.

[0054] Next, a method for obtaining the elevation angle θa will be described.

[0055] The elevation angle θa can be obtained from the geometric relationship between the position P1 and the position P1a by the following equation (1) using the azimuth angle φ and the elevation angle θ.

[0056]

Equation

[0057]

Equation

[0058]

Equation

[0059] Also, as described above, the focal length of the fisheye lens 141 is fL Then, the radial distance r is expressed by the following equation (4).

[0060]

Equation

[0061]

Equation

[0062] Next, the method for obtaining the phase data will be described. FIG. 4 is a diagram for explaining the method for obtaining the phase data. FIG. 4 shows the fisheye lens 141 of the camera 140, the marker 50A, the power receiving device 50B, and N antenna elements 111. Each antenna element 111 is one of the four antenna elements 111 included in N sub-arrays 110A. The position of the marker 50A is equal to the position of the power receiving device 50B.

[0063] As shown in FIG. 4, let the distances from the N sub-arrays 110A to the marker 50A be r1 to rN. Here, for simplicity of explanation, it is assumed that there is no displacement in the Y-axis direction between the camera 140 and the marker 50A. Since the centers of the 4N antenna elements 111 coincide with the origin of the XYZ coordinate system, the coordinates of the centers of the 4N antenna elements 111 are (X, Y, Z) = (0, 0, 0). Also, since there is no displacement in the Y-axis direction between the camera 140 and the marker 50A and the facing distance is r FD and the angle of the power receiving device 50B as seen from the fisheye lens 141 is θb, the position of the power receiving device 50B can be expressed as (X, Y, Z) = (r FD ·tanθb, 0, r FD ). Here, if the distance from the fisheye lens 141 to the power receiving device 50B is r ref then the distance r ref can be expressed by the following equation (6).

[0064]

Equation

[0065] When the position of the i-th antenna element 111 among the N antenna elements 111 is (X, Y, Z) = (d i , 0, 0), the distance r from the i-th antenna element 111 to the power receiving device 50B i can be expressed by the following equation (7).

[0066]

Equation

[0067] Therefore, the path difference τ between the distance r from the fish-eye lens 141 to the power receiving device 50B ref and the distance ri from the i-th antenna element 111 to the power receiving device 50B i can be expressed by the following equation (8).

[0068]

Equation

[0069] The path difference τ i is in meters, so it is converted to the phase difference φ in terms of the wavelength λ of the microwave used i and can be expressed by the following equation (9).

[0070]

Equation

[0071] -ψr FDi (θb) obtained by inverting the sign of the phase difference expressed by Equation (9) is set as the phase to be set in the phase shifter 120 when the i-th antenna element 111 transmits power. For the N sub-arrays 110A, a plurality of sets of phase data corresponding to a plurality of elevation angles θa are prepared and stored in the memory 156. Also, for a plurality of opposing distances r FDPrepare multiple sets of phase data for and store them in the memory 156. By using such multiple sets of phase data, the power transmission signals transmitted from the N sub-arrays 110A can reach the power receiving device 50B in the same phase. The multiple sets of phase data corresponding to the multiple angles θb are represented by the following equation (10).

[0072] [Number]

[0073] The control unit 155 may set the shift amounts in the N phase shifters 120 respectively connected to the N sub-arrays 110A by using the phase data of the angle θb corresponding to the elevation angle θa.

[0074] FIG. 5 is a diagram for explaining the effects of the antenna device 100A and the power feeding device 100. In FIG. 5, the opposing distance r FD is 4 m, and it is a diagram showing the antenna gain received by the power receiving antenna of the power receiving device when the speed of the vehicle equipped with the antenna device 100A and the power feeding device 100 is 80 km / h. The horizontal axis represents time, 0 seconds represents the time when the elevation angle θa is 0 degrees, -300 seconds represents the time when the elevation angle θa is +70 degrees, and +300 seconds represents the time when the elevation angle θa is -70 degrees. That is, the time on the horizontal axis corresponds to the elevation angle θa.

[0075] Also, in FIG. 5, the antenna gain when the shift amount in the phase shifter 120 is adjusted by using the phase data based on the opposing distance and the elevation angle with the antenna device 100A and the power feeding device 100 is shown by a solid line, and the antenna gain when using the phase data based only on the elevation angle for comparison is shown by a dashed line. The antenna gain when using the phase data based only on the elevation angle is the antenna gain obtained by the power receiving device 50B when the shift amounts in the N phase shifters 120 connected to the N sub-arrays 110A are set to values corresponding to the elevation angle θa.

[0076] As shown in FIG. 5, the antenna gain when using phase data based on the opposing distance and elevation angle is greater than or equal to the antenna gain when using phase data based only on the elevation angle, and the closer the time zone is to 0 seconds (the smaller the absolute value of the elevation angle θa), the greater the difference between the antenna gain when using phase data based on the opposing distance and elevation angle and the antenna gain when using phase data based only on the elevation angle. The closer the elevation angle θa is to 0 degrees, the shorter the distance between the N sub-arrays 110A and the power receiving device 50B, and it is considered that the effect of individual phase control of the N sub-arrays 110A by the phase data based on the opposing distance and elevation angle becomes remarkable.

[0077] <Configuration of Marker 50A> FIG. 6 is a diagram showing the marker 50A. The vertical direction in FIG. 6 represents the vertical direction when the marker 50A is installed. As shown in FIG. 6(A), the marker 50A has an upper end 50AU, a lower end 50AL, and a wide portion 50AW. As an example, the marker 50A includes a reflector that reflects infrared rays by retroreflection (retroreflectivity), and can reflect infrared rays over the entire surface of the marker 50A.

[0078] The marker 50A has a vertically long (vertically cylindrical) shape, the width of the wide portion 50AW is the widest (thickest), and the widths of the upper end 50AU side and the lower end 50AL side are thinner than the wide portion 50AW. Also, as an example, the vertical length of the portion on the upper end 50AU side than the wide portion 50AW and the vertical length of the portion on the lower end 50AL side than the wide portion 50AW are equal. Note that the marker 50A only needs to be able to reflect infrared rays and visible light, and the coordinates of the upper end 50AU, the lower end 50AL, and the center of gravity can be obtained by image processing of the camera 140, and the configuration shown here is an example.

[0079] Further, FIG. 6(B) shows an example of pixel indices obtained by the image processing unit 142B performing image processing such as binarization processing on the image data acquired by the imaging unit 142A. In FIG. 6(B), the horizontal axis is the x-axis and the vertical axis is the y-axis. The x-axis and the y-axis are the same as the x-axis and the y-axis of the plane 1 shown in FIG. 3, and the origin is also the same.

[0080] The pixel index includes the contour of the marker 50A, and the coordinates of the upper end 50AU are (x U , y U ), the coordinates of the lower end 50AL are (x L , y L ), and the coordinates of the center of gravity of the marker 50A are (x C , y C ). The contour of the marker 50A is obtained by the image processing unit 142B performing a process of extracting the contour based on the distribution of the pixel index. Since the actual pixel index may include small contours caused by noise or the like in addition to the contour of the marker 50A, the contour of the marker 50A is obtained by performing a process of obtaining the maximum contour that obtains the largest contour from among a plurality of contours extracted based on the distribution of the pixel index. Further, the image processing unit 142B obtains the coordinates of the upper end 50AU and the lower end 50AL from the contour of the marker 50A obtained as the maximum contour. The coordinates of the center of gravity are obtained by the position derivation unit 151.

[0081] The reason why the marker 50A has the above-described configuration is that when the position derivation unit 151 calculates the center of gravity of the image of the marker 50A based on the pixel index output from the image processing unit 142B, the deviation of the position of the center of gravity with respect to the center of the marker 50A (the center in the vertical direction and the center in plan view) is made as small as possible. It is ideal that the center of the marker 50A is derived as the center of gravity of the marker 50A by the position derivation unit 151.

[0082] The reason for making the deviation of the position of the center of gravity with respect to the center of the marker 50A as small as possible is to make the deviation of the height in the Y-axis direction between the center of gravity of the marker 50A and the origin O as small as possible in the polar coordinate system shown in FIG. 3, so as to accurately obtain the elevation angle θa in the XZ plane and perform phase control with high accuracy.

[0083] In addition, by using the coordinates of the upper end 50AU, the lower end 50AL, and the center of gravity of the marker 50A, and the length data representing the vertical length of the marker 50A, it becomes possible to estimate in real time the facing distance Z in the Z-axis direction from the origin O to the marker 50A. The possibility of estimating the facing distance Z will be described later with reference to FIG. 7.

[0084] Here, the form in which the image processing unit 142B obtains the coordinates of the upper end 50AU and the lower end 50AL of the marker 50A will be described. However, it is not necessarily required to be the upper end 50AU and the lower end 50AL of the marker 50A. For example, when the reflector is provided up to a portion offset downward from the upper end of the marker 50A, the coordinates of the upper end portion where the reflector exists among the portions on the upper end side of the marker 50A may be used. Further, when the reflector is provided up to a portion offset upward from the lower end of the marker 50A, the coordinates of the lower end portion where the reflector exists among the portions on the lower end side of the marker 50A may be used. As the length data representing the vertical length of the marker 50A, length data representing the length between the upper end portion and the lower end portion may be used.

[0085] <Method for Estimating the Facing Distance Z in Real Time> FIG. 7 is a diagram showing the polar coordinate system of the array antenna 110. The process of estimating the facing distance Z is executed by the control device 150. The method for estimating the facing distance Z is realized by executing the process of estimating the facing distance Z.

[0086] In FIG. 7, similar to FIG. 3, the sub-array 110A of the array antenna 110, the antenna elements 111 included in each sub-array 110A, and the beam 115 output from the array antenna 110 are shown. In addition to these, FIG. 7 also shows the marker 50A. The marker 50A is configured such that the center 50AC1 and the center of gravity 50AC2 coincide. However, since the center of gravity 50AC2 derived by the position derivation unit 151 based on the maximum contour of the pixel index may deviate from the center 50AC1, in FIG. 7, the center 50AC1 and the center of gravity 50AC2 are shown separately.

[0087] The Y coordinate of the center 50AC1 of the marker 50A is Y = 0. That is, the height of the center 50AC1 of the marker 50A in the Y-axis direction is aligned with the height of the origin O of the XYZ coordinate system. Also, the coordinates of the upper end 50AU, the lower end 50AL, and the center of gravity 50AC2 of the marker 50A in the XYZ coordinates are, respectively, (X, Y U , Z), (X, Y L , Z), (X, Y C , Z). Since the marker 50A extends parallel to the Y-axis, the X coordinates and Z coordinates of the upper end 50AU, the lower end 50AL, and the center of gravity 50AC2 are the same. In FIG. 7, the marker 50A is simplified and shown as a cylinder.

[0088] Also, the polar coordinates of the upper end 50AU are the elevation angle θ U , the azimuth angle φ U , and the polar coordinates of the lower end 50AL are the elevation angle θ L , the azimuth angle φ L . The polar coordinates of the center of gravity 50AC2 are the elevation angle θ C , the azimuth angle φ C . The elevation angle θ U is an example of the second elevation angle, and the elevation angle θ L is an example of the third elevation angle. Also, the points obtained by projecting the upper end 50AU, the lower end 50AL, and the center of gravity 50AC2 onto the plane 1 are P3 U , P3 L , P3 C . Let the xy coordinates of the points P3 U , P3 L , P3 C in the plane 1 be (x U , y U ), (x L , y L ), (x C , y C ), respectively. Also, the radii of the points P3 U , P3 L , P3 C are r U , r L , r C , respectively.

[0089] The radius r C of the center of gravity 50AC2 is the focal length f L of the fish-eye lens 141 and the elevation angle θ of the center of gravity 50AC2C When using r C = f L θ C it is represented by. Also, the xy coordinates (x C , y C ) of the centroid 50AC2, when using the radial distance r C and the azimuth angle φ C are such that x C = r C cos φ C , y C = r C sin φ C . Therefore, the coordinates (x C , y C ) of the centroid 50AC2 can be expressed by the following equations (11) and (12).

[0090]

Equation

[0091]

Equation

[0092] When fitting the elevation angle θa shown in Equation (3) to the centroid 50AC2, the following equation (13) holds. Here, θa = x C / f L holds because for the centroid 50AC2, r C = f L θ C holds. The elevation angle θa is an example of the first elevation angle.

[0093]

Equation

[0094] The elevation angle θ U and the azimuth angle φ U of the upper end 50AU can be expressed by the following equations (14) and (15) when using the XYZ coordinates (X, Y U , Z) of the upper end 50AU.

[0095]

Number

[0096]

Number

[0097] The radial distance r of the upper end 50AU U is the focal length f of the fish-eye lens 141 L and the elevation angle θ of the upper end 50AU U Using these, r U = f L θ U is expressed as. Also, the xy coordinates (x U , y U ) on the plane 1 of the upper end 50AU are x U = r U cosφ U , y U = r U sinφ U = r U sinφ U U . Therefore, the coordinates (x, y U ) of the upper end 50AU can be expressed by the following equations (16) and (17).

[0098]

Number

[0099]

Number

[0100] Also, similar to the upper end 50AU, the elevation angle θ L and the azimuth angle φ L of the lower end 50AL can be expressed by the following equations (18) and (19) using the XYZ coordinates (X, Y L , Z) of the lower end 50AL.

[0101]

Number

[0102] [Numerical]

[0103] The radial distance r of the lower end 50AL L is the focal length f of the fish-eye lens 141 L and the elevation angle θ of the lower end 50AL L When used, r L = f L θ L is represented by. Also, the xy coordinates (x L , y L ) on the plane 1 of the lower end 50AL, when using the radial distance r L and the azimuth angle φ L , x L = r L cos φ L , y L = r L sin φ L are. Therefore, the coordinates (x L , y L ) of the lower end 50AL can be represented by the following equations (20) and (21).

[0104] [Numerical]

[0105] [Numerical]

[0106] When equations (15) and (19) are transformed, the following equations (22) and (23) are obtained respectively.

[0107] [Numerical]

[0108] [Numerical]

[0109] Taking the difference between Equation (22) and Equation (23), the following Equation (24) is obtained.

[0110]

Number

[0111] Therefore, the distance X in the X-axis direction between the center of the fisheye lens 141, which is the origin O of the XYZ coordinate system, and the centroid 50AC2 of the marker 50A can be estimated as the following Equation (25) from Equation (24). The distance X hat is an estimated value. The distance X is the X-axis direction component of the distance between the center of the fisheye lens 141, which is the origin O of the XYZ coordinate system, and the centroid 50AC2 of the marker 50A.

[0112]

Number

[0113] Also, the center 50AC1 of the marker 50A is at the same height as the center of the fisheye lens 141, which is the origin O of the XYZ coordinate system, and for the Y coordinate (Y C ) of the centroid 50AC2, Y C ≈ 0 holds. Also, when the Y coordinate of the point P1 of the elevation angle θ shown in FIG. 3 is set to 0 (Y = 0), the elevation angle θ can be considered to be the elevation angle θa obtained by projecting the elevation angle θ onto the XZ plane. Therefore, the opposing distance Z in the Z-axis direction between the center of the fisheye lens 141, which is the origin O of the XYZ coordinate system, and the centroid 50AC2 of the marker 50A can be expressed by the following Equation (26). The opposing distance Z hat is an estimated value.

[0114]

Number

[0115] Here, the length L PM between the upper end 50AU and the lower end 50AL of the marker 50A is U Y LTherefore, the following equation (27) is obtained from equation (26).

[0116] [Number]

[0117] Note that Y U -Y L is also included in the numerator of equation (25) for estimating the distance X. Therefore, substitute the length L PM into the numerator of equation (25) to estimate the distance X, and use the estimated distance X hat and the elevation angle θa to obtain the opposing distance Z hat from equation (26).

[0118] Since the distance estimation unit 154 estimates the opposing distance Z using the image data, the opposing distance Z hat is an estimated value. Such an opposing distance Z cannot be obtained when the elevation angle θa is 0 degrees because the values of x U and x L and tanθa become 0, but it can be obtained in real time when the elevation angle θa is other than 0 degrees. The opposing distance Z is the Z component (distance in the Z-axis direction) of the distance between the center of the array antenna 110 (the origin O of the XYZ coordinate system) and the centroid 50AC2 of the marker 50A. The center of the array antenna 110 (the origin O of the XYZ coordinate system) is the center of the fisheye lens 141.

[0119] When the power supply device 100 mounted on the vehicle moves with respect to the marker 50A and the power receiving device 50B, the relative position of the marker 50A as seen from the power supply device 100 changes every moment. Therefore, it is possible to detect and track the centroid 50AC2 of the marker 50A using the image data of the marker 50A. However, since the opposing distance Z hat is a substantially constant value, the opposing distance Z may be estimated at predetermined discrete angles (for example, 60 degrees, 50 degrees, 40 degrees, 30 degrees, 20 degrees) of the elevation angle θa, and the average of the opposing distance Z hats estimated at a plurality of discrete angles may be taken, and phase control may be performed using the average value of the opposing distance Z hats.

[0120] The distance Rref between the center of the array antenna 110 (the origin O of the XYZ coordinate system) and the power receiving antenna of the power receiving device can be obtained by the following equation (28).

[0121]

Equation

[0122] Here, since the height of the center 50AC1 of the marker 50A is aligned with the height of the origin O of the XYZ coordinate system, it can be considered that Y = 0 in Equation (28). The distance Ri between the antenna element 111 included in the i-th sub-array 110A among the N sub-arrays 110A and the power receiving antenna of the power receiving device can be expressed by the following equation (29) using Equation (28).

[0123]

Equation

[0124]

Equation

[0125] When the opposing distance Z hat and the elevation angle θa are given, in order to align the phases of the transmission signals received by the antenna of the power receiving device 50 from the antenna elements 111 included in the N sub-arrays 110A, the phase of the transmission signal supplied to the antenna element 111 of the i-th sub-array 110A is as follows in Equation (31).

[0126] [Number] Here, λ is the wavelength of the microwave used for power transmission.

[0127] The phase represented by Equation (31) is based on the same concept as the above-described phase data and may be used instead of the phase data. Since the phase represented by Equation (31) can be calculated in real time, phase control may be performed by calculating it in real time. When calculating the phase using Equation (31), for example, the control unit 155 may perform the calculation. Also, it is not always necessary to calculate in real time. The phase may be obtained for several discrete opposing distances Z hat and elevation angles θa, stored in the memory 156, and the phase corresponding to the opposing distance Z hat and elevation angle θa estimated in real time may be read out for phase control.

[0128] <Estimation Process of Opposing Distance Z in Real Time> Figure 8 is a flowchart showing the estimation process of the opposing distance Z. When the process starts, the image processing unit 142B reads the luminance value of each pixel of the image data acquired by the imaging unit 142A (step S1).

[0129] The image processing unit 142B performs binarization on the image data acquired by the imaging unit 142A and obtains the distribution of pixel indices (step S2).

[0130] The image processing unit 142B extracts one or more contours based on the distribution of pixel indices (step S3).

[0131] The image processing unit 142B performs a process of obtaining the largest contour (maximum contour) from the one or more contours extracted based on the distribution of pixel indices (step S4).

[0132] The position derivation unit 151 calculates the centroid of the maximum contour included in the pixel index obtained by the image processing unit 142B (step S5A). As a result, the coordinates of the centroid 50AC2 of the marker 50A are derived. The position derivation unit 151 treats the centroid of the maximum contour as the coordinates of the centroid 50AC2.

[0133] The image processing unit 142B reads the coordinates of the upper end and the lower end of the maximum contour obtained by the image processing unit 142B (step S5B). As a result, the coordinates of the upper end 50AU and the lower end 50AL of the marker 50A are obtained. The process of step S5B is performed in parallel with step S5A. The image processing unit 142B outputs the read coordinates of the upper end and the lower end of the maximum contour to the control device 150 as the coordinates of the upper end 50AU and the lower end 50AL of the marker 50A.

[0134] The elevation angle acquisition unit 152 obtains the elevation angle θ of the centroid 50AC2 C and the azimuth angle φ C and obtains the elevation angle θa based on Equation (13) (step S6A). The elevation angle θ of the centroid 50AC2 C and the azimuth angle φ C may be obtained from the coordinates (x C , y C ) of the centroid 50AC2.

[0135] The distance estimation unit 154 reads the data representing the length L PM from the memory 156 and estimates the distance X using Equation (25) (step S6B).

[0136] The distance estimation unit 154 estimates the opposing distance Z using Equation (26) based on the distance X^ and the elevation angle θa (step S7).

[0137] <Simulation result of received power amount> Figure 9 is a diagram showing the simulation results of the received power. These simulation results were obtained by setting the opposing distance Z to 3 m. In Figure 9, the horizontal axis is time (ms), the left vertical axis is the elevation angle θa (degrees), and the right vertical axis is the received power (mJ) of the power receiving device 50B. The received power is the amount of received power that the power receiving device 50 receives from the power feeding device 100. Also, in Figure 9, the dashed-dotted line indicates the time change of the elevation angle θa. The solid line indicates the time change of the received power of the power receiving device 50B that receives power from the power feeding device 100. The dashed line indicates the time change of the received power of the power receiving device 50B that receives power from a comparative power feeding device.

[0138] Here, the comparative power feeding device transmits a power transmission signal such that the phases of the power transmission signals transmitted from the antenna elements 111 of all the sub-arrays 110A from #1 to #N are equal, and transmits the power transmission signal toward the power receiving device 50B existing in the direction of the elevation angle θa. For this reason, the phases of the power transmission signals received by the power receiving antenna of the power receiving device from the antenna elements 111 of the N sub-arrays 110A of the comparative power feeding device are not aligned.

[0139] Assuming that the power feeding device 100 has moved in the X-axis direction with respect to the power receiving device 50B, when the elevation angle θa was changed from +30 degrees to -30 degrees as shown in Figure 9, the received power from the power feeding device 100 was approximately 50% more than the received power from the comparative power feeding device. As a result, while estimating the opposing distance Z in real time with the power feeding device 100, by performing phase control so that the phases of the power transmission signals transmitted from the antenna elements 111 of all the sub-arrays 110A from #1 to #N are aligned at the power receiving antenna of the power receiving device located in the direction of the elevation angle θa, it was confirmed that the received power of the power receiving device 50B can be significantly increased.

[0140] As described above, by using Equation (25) and Equation (26), or Equation (25) to Equation (27), the distance estimation unit 154 can use the length L between the upper end 50AU and the lower end 50AL of the marker 50A PM to estimate in real time the opposing distance Z between the center of the fisheye lens 141, which is the origin O of the XYZ coordinate system, and the centroid 50AC2 of the marker 50A. The opposing distance Z represents the estimated value of the Z coordinate of the centroid 50AC2 of the marker 50A as seen from the origin O.

[0141] Therefore, it is possible to provide a distance estimation device 100B, an antenna device 100A, a power feeding system, a power feeding device 100, and a power feeding method that can estimate the facing distance Z hat between the power receiving device 50B and the power feeding device 100 in real time.

[0142] When the elevation angle θa is not included in a predetermined angle range including 0 degree, the distance estimation unit 154 can estimate the facing distance Z in real time. The predetermined angle range is, for example, a range in which it is not suitable for the distance estimation unit 154 to calculate the facing distance Z hat using the formula (27), and is a predetermined range around the angle at which the elevation angle θa becomes 0 degree.

[0143] Further, as shown by the formula (25), the distance estimation unit 154 can also estimate the distance X in the X-axis direction in real time when the elevation angle θa is not included in a predetermined angle range including 0 degree. The Y in the numerator of the formula (25) U -Y L is the length L between the upper end 50AU and the lower end 50AL of the marker 50A PM and the denominator tan φ U , tan φ L can be calculated from the xy coordinates (x U , y L ), (x U , y U ) of the points P3 L , P3 L ) as shown in the formula (27). Similar to the facing distance Z hat, the distance estimation unit 154 can estimate the distance X when the elevation angle θa is not included in a predetermined angle range including 0 degree.

[0144] Further, since the length of the marker 50A in the vertical direction is longer than the length in the horizontal direction, the center of gravity of the marker 50A derived by the position derivation unit 151 from the contour included in the pixel index is likely to coincide with the center in the vertical direction of the marker 50A, and the positional deviation of the center of gravity from the center can be reduced. As a result, the elevation angle θa can be calculated with high accuracy, and phase control can be performed with high accuracy.

[0145] In addition, since the marker 50A has a wide portion 50AW at the central portion in the vertical direction, the position of the center of gravity of the marker 50A derived by the position derivation unit 151 from the contour included in the pixel index can be guided to the central portion of the marker 50A. As a result, the elevation angle θa can be calculated with high precision, and phase control can be performed with high precision.

[0146] In addition, since the wide portion 50AW is located at the center in the vertical direction of the marker 50A, the position of the center of gravity of the marker 50A derived by the position derivation unit 151 from the contour included in the pixel index can be guided to the center of the marker 50A. As a result, the elevation angle θa can be calculated with higher precision, and phase control can be performed with higher precision.

[0147] In addition, since length data representing the length between the upper end 50AU and the lower end 50AL of the marker 50A is stored in the memory 156, the calculation of the distance X hat or the opposing distance Z hat can be easily performed.

[0148] In addition, since the upper end portion and the lower end portion of the marker 50A are the upper end and the lower end of the marker 50A, respectively, the pixel index can be easily obtained.

[0149] In addition, phase data for a plurality of sets is stored in the memory 156 for a plurality of opposing distances r FD and the distance estimation unit 154 estimates the opposing distance r FD so that the shift amounts in the N phase shifters 120 respectively connected to the N sub-arrays 110A can be set using the phase data for a plurality of sets corresponding to the opposing distance r FD . Therefore, by using the phase data for a plurality of sets corresponding to the distance in the Z-axis direction to the power receiving device 50B, it is possible to provide the power transmitting antenna device 100A and the power supply device 100 that can transmit power so that the power receiving device 50B can efficiently receive power even at a short distance according to the distance in the Z-axis direction to the power receiving device 50B. Note that, for example, when there is no phase data for a plurality of sets corresponding to the opposing distance r FD , the opposing distance r FD estimated is the opposing distance r FDPhase data corresponding thereto may be used.

[0150] Also, the plurality of antenna elements 111 are grouped into a plurality of sub-arrays 110A extending along the Y-axis direction, and the phase shifter 120 is connected to each of the plurality of sub-arrays 110A to adjust the phase of the transmission signal for each sub-array 110A. Therefore, with phase control in the X-axis direction, it is possible to transmit a transmission signal with aligned phases to the power receiving device 50B. Also, since phase control is performed only by phase control in the X-axis direction, phase control can be simplified.

[0151] Also, when the elevation angle θa is included in a predetermined angle range including 0 degrees, as shown in FIG. 3, the distance estimation unit 154 converts the position P1 obtained by equidistant projection into polar coordinates on a plane 1 parallel to the XY plane to obtain the position P2, and further maps the position P2 to the X-axis to obtain the X coordinate (r·cosφ) of the mapped position P2a of the focus distance f of the fisheye lens 141 L and divides by to obtain the elevation angle θa (=r·cosφ / f L ).

[0152] Then, the control unit 155 may set the shift amounts in the N phase shifters 120 respectively connected to the N sub-arrays 110A by using the phase data of the angle θb corresponding to the elevation angle θa. By controlling the shift amounts in the N phase shifters 120 by using the phase data corresponding to the change in the elevation angle θa accompanying the movement of the antenna device 100A and the power supply device 100, it is possible to transmit a transmission signal that always reaches the power receiving antenna of the power receiving device with the same phase from the N sub-arrays 110A while the antenna device 100A and the power supply device 100 are moving.

[0153] Also, when the elevation angle θa is within a predetermined angle range including 0 degrees, the position displacement detection unit 153 detects the position displacement between the camera 140 and the marker 50A in the Y-axis direction. When a position displacement occurs, the distance estimation unit 154 reads data representing the degree of change in the pixel index number for the position displacement in the Y-axis direction from the memory 156, and uses the pixel index number corrected according to the degree of the position displacement in the Y-axis direction to estimate the opposing distance r FD Thereby, when the elevation angle θa is within a predetermined angle range including 0 degrees and a position displacement occurs between the camera 140 and the marker 50A in the Y-axis direction, the control unit 155 uses the corrected pixel index number to estimate the opposing distance r FD By using a plurality of sets of phase data corresponding to the opposing distance r, even when a position displacement occurs between the camera 140 and the marker 50A in the Y-axis direction, the power receiving device 50B can efficiently receive power at a short distance according to the distance in the Z-axis direction to the power receiving device 50B, and it is possible to provide the power transmission antenna device 100A capable of power transmission, and the power supply system, the power supply device 100, and the power supply method.

[0154] In addition, since the antenna device 100A and the power supply device 100 control the elevation angle of the beam 115 output by the array antenna 110 only within the XZ plane, the number of phase shifters 120 is only one-fourth compared to the case where the elevation angle is controlled in both the XZ plane and the YZ plane. Therefore, the antenna device 100A and the power supply device 100 can be realized at low cost.

[0155] Note that, in the above, the form in which the center of the fisheye lens 141 coincides with the center of the 4N antenna elements 111 has been described. However, the center of the fisheye lens 141 may be displaced from the center of the 4N antenna elements 111. In this case, the coordinate origin of the array antenna control phase calculation may be shifted by the amount of the displacement. Alternatively, the marker 50A and the power receiving antenna may be installed at a distance corresponding to the amount of the displacement.

[0156] In the above description, the form in which the control device 150 includes the misalignment detection unit 153 has been described. However, for example, when it is known that no misalignment occurs between the camera 140 and the marker 50A, the control device 150 does not include the misalignment detection unit 153, and the distance estimation unit 154 does not have to perform correction corresponding to the misalignment.

[0157] <Application Example of Power Feeding Device 100 and Power Feeding System 10> FIG. 10 is a diagram showing an application example of the power feeding device 100. The power feeding device 100 is mounted on a vehicle 60 as an example, and a power receiving antenna 50C as a target is provided on the inner wall 51 of the tunnel. A marker 50A and a power receiving device 50B are attached to the power receiving antenna 50C. The marker 50A is the marker 50A shown in FIG. 6(A), and the power receiving antenna 50C is disposed adjacent to the wide portion 50AW of the marker 50A. This is to efficiently receive power with the power receiving antenna 50C because the power feeding device 100 radiates a beam of a power transmission signal toward the centroid 50AC2 obtained from the image data of the marker 50A. The distance between the inner wall 51 of the tunnel and the vehicle 60 varies for each tunnel passed through. Further, when the vehicle 60 travels, if the vehicle 60 travels in an oblique direction with respect to the travel lane, the distance between the inner wall 51 and the vehicle 60 may change from moment to moment.

[0158] Here, the system including the power feeding device 100, the marker 50A, the power receiving device 50B, and the power receiving antenna 50C is the power feeding system 10 of the embodiment. Since the power feeding device 100 includes the antenna device 100A and the microwave generation source 130, the power feeding system 10 includes the antenna device 100A, the microwave generation source 130, the marker 50A, the power receiving device 50B, and the power receiving antenna 50C.

[0159] When the vehicle 60 travels in the +X axis direction, the power feeding device 100 converts the position of the marker 50A into polar coordinates on a plane parallel to the XY plane with the camera 140, and further maps the X coordinate (r·cosφ) of the mapped position (the mapped position corresponding to P2a) on the X axis by the focal length f of the fisheye lens 141 L and divides by it to obtain the elevation angle θa (=r·cosφ / f LFind it. Also, the power supply device 100 obtains the opposing distance Z-hat in real time based on the image data of the marker 50A and the vertical length LPM of the marker 50A, reads out the phase data corresponding to the opposing distance Z-hat and the elevation angle θa from the memory 156, and controls the shift amounts in the N phase shifters 120. Then, while the power supply device 100 is moving, a transmission signal with the same phase can always be transmitted from the N sub-arrays 110A to the power receiving antenna 50C of the power receiving device 50B. The transmission signal with the same phase is irradiated onto the power receiving antenna 50C as a beam. Also, instead of reading out the phase data from the memory 156, the power supply device 100 may set the phase of the transmission signal transmitted from the N sub-arrays 110A in real time using the above-described formula (9).

[0160] Also, when the elevation angle θa is included in a predetermined angle range including 0 degrees, the distance estimation unit 154 estimates the opposing distance r from the center of the fisheye lens 141 to the marker 50A based on the number of pixel indices acquired by the image processing unit 142B FD It may be estimated. Also, the power supply device 100 estimates the opposing distance Z every predetermined discrete angle (for example, 60 degrees, 50 degrees, 40 degrees, 30 degrees, 20 degrees), takes the average of the opposing distances Z-hat estimated at a plurality of discrete angles, and performs phase control using the average value of the opposing distances Z-hat.

[0161] For example, a power receiving antenna 50C, a sensor for monitoring loosening of bolts or the like of the fixing part, a rectenna, and a wireless communication module are provided on a fixing part that fixes infrastructure structures such as a jet fan or a sign attached to the inner wall 51 of the tunnel to the inner wall 51. When a beam is radiated from the power supply device 100 to the power receiving antenna 50C while the vehicle 60 is running, the rectenna connected to the power receiving antenna 50C generates power and activates the wireless communication module. The wireless communication module radiates a signal representing the output of the sensor and the vehicle 60 side receives it, so that the fixing state of the infrastructure structure can be inspected while running.

[0162] In this case, the array antenna 110 may receive a signal representing the output of the sensor by the wireless communication module.

[0163] Also, the X coordinate (r·cosφ) of the mapping position (the mapping position corresponding to P2a) mapped to the X axis from the position of the power receiving antenna 50C shifted from the XZ plane is obtained, and the X coordinate (r·cosφ) is divided by the focal length f L of the fisheye lens 141, and the value (r·cosφ / f L ) is used as the elevation angle θa to control the beam. Therefore, even when the vehicle 60 traveling in the X-axis direction is shifted to either the plus or minus side of the Y axis, the positional deviation can be absorbed to obtain the elevation angle θa.

[0164] Also, here, the form in which the power feeding device 100 (antenna device 100A) communicates with the wireless communication module provided on the inner wall 51 of the tunnel has been described with reference to FIG. 10. However, the wireless communication module is not limited to being provided on the inner wall 51 of the tunnel and may be installed in various places and the like. In this way, the power feeding device 100 (antenna device 100A) can be used as a communication device.

[0165] As described above, the distance estimation device, antenna device, power feeding system, power feeding device, and power feeding method according to the exemplary embodiments of the present invention have been described. However, the present invention is not limited to the specifically disclosed embodiments, and various modifications and changes are possible without departing from the scope of the claims.

Explanation of Reference Numerals

[0166] 50A Marker 50B Power receiving device 50C Power receiving antenna 100 Power feeding device 100A Antenna device 100B Distance estimation device 110 Array antenna 110A Sub-array 111 Antenna element 120 Phase shifter 130 Microwave generation source 140 Camera 141 Fisheye lens 150 Control device 151 Position derivation unit 152 Elevation angle acquisition unit 153 Position deviation detection unit 154 Distance estimation unit 155 Control unit 156 Memory

Claims

1. an image acquisition unit that acquires an image through a fish-eye lens; a position derivation unit that converts a first position of a marker included in the image acquired by the image acquisition unit with respect to the image acquisition unit into a second position in polar coordinates on a first plane including a first axis and a second axis; an elevation angle acquisition unit that acquires a first elevation angle with respect to a third axis within the second plane of a projection position obtained by projecting the first position onto a second plane including the first axis and a third axis based on the second position; a distance estimation unit that estimates a distance between the image acquisition unit and the marker and comprising: wherein the distance estimation unit estimates a distance in the first axis direction between the image acquisition unit and the marker based on coordinates of an upper end portion of the marker included in the image, which are obtained from a second elevation angle with respect to the third axis and an azimuth angle with respect to the first axis, coordinates of a lower end portion of the marker included in the image, which are obtained from a third elevation angle with respect to the third axis and an azimuth angle with respect to the first axis, and a length between the upper end portion and the lower end portion; a distance estimation device that estimates a distance in the third axis direction between the image acquisition unit and the marker based on the first elevation angle acquired by the elevation angle acquisition unit and the estimated distance in the first axis direction.

2. The distance estimation device according to claim 1, wherein the distance estimation unit estimates a distance in the first axis direction between the image acquisition unit and the marker when the first elevation angle acquired by the elevation angle acquisition unit is not included in a predetermined angle range including zero degrees, and estimates a distance in the third axis direction between the image acquisition unit and the marker based on the first elevation angle acquired by the elevation angle acquisition unit and the estimated distance in the first axis direction.

3. The distance estimation device according to claim 2, wherein the distance estimation unit estimates a distance in the third axis direction from the image acquisition unit to the marker based on the image acquired by the image acquisition unit when the first elevation angle acquired by the elevation angle acquisition unit is included in the predetermined angle range including zero degrees.

4. further comprising a position deviation detection unit that detects a position deviation between the image acquisition unit and the marker in the second axis direction based on a position of the center of gravity of the marker included in the image acquired by the image acquisition unit. When the first elevation angle acquired by the elevation angle acquisition unit is included in the predetermined angle range including 0 degrees, the distance estimation unit estimates the distance in the third axis direction from the image acquisition unit to the marker based on the image corrected according to the degree of positional deviation detected by the positional deviation detection unit. The distance estimation device according to claim 3.

5. The upper end portion and the lower end portion are, respectively, the upper end and the lower end of the marker. The distance estimation device according to any one of claims 1 to 4.

6. The elevation angle acquisition unit obtains, as the first elevation angle, a value obtained by dividing the coordinates of the mapping position obtained by mapping the second position onto the first axis by the focal length of the fisheye lens. The distance estimation device according to any one of claims 1 to 5.

7. The coordinates of the mapping position are represented by a value obtained by multiplying the radial distance in the polar coordinates by the cosine of the declination angle. The distance estimation device according to claim 6.

8. The distance estimation device according to any one of claims 1 to 7, An array antenna having a plurality of antenna elements two-dimensionally arranged along the first axis and the second axis, A phase adjustment unit that adjusts the phase of the transmission signal supplied to the plurality of antenna elements in the first axis direction, A control unit that controls the phase adjustment unit based on the first elevation angle acquired by the elevation angle acquisition unit and the distance in the third axis direction estimated by the distance estimation unit An antenna device including.

9. The plurality of antenna elements are grouped into a plurality of sub-arrays extending along the second axis direction, The phase adjustment unit is a plurality of phase shifters respectively connected to the plurality of sub-arrays and adjusting the phase of the transmission signal for each sub-array. The antenna device according to claim 8.

10. The antenna device according to claim 8 or 9, further including a storage unit that stores length data representing the length between the upper end portion and the lower end portion of the marker.

11. When transmitting the transmission signal from the plurality of antenna elements to the power receiving device located at the position of the marker, a plurality of phases are adjusted so that the phases at which the power receiving device receives the transmission signal from the plurality of antenna elements are aligned. The storage unit further stores a plurality of sets of phase data corresponding to a plurality of the first elevation angles. The storage unit stores a plurality of sets of the phase data according to a plurality of types of distances from the image acquisition unit to the marker. The control unit reads out the phase data corresponding to the distance in the third axis direction estimated by the distance estimation unit and the first elevation angle acquired by the elevation angle acquisition unit from the storage unit, and controls the phase adjustment unit based on the read phase data. The antenna device according to claim 8 or 9.

12. The antenna device according to any one of claims 8 to 11, A radio wave source that supplies the transmission signal to the plurality of antenna elements, A power receiving device located at the position of the marker, The marker attached to the power receiving device including The marker has a longer length in the vertical direction than in the horizontal direction. A power supply system.

13. The marker has a wide portion at the central portion in the vertical direction. The power supply system according to claim 12.

14. The wide portion is located at the center in the vertical direction. The power supply system according to claim 13.

15. An array antenna having a plurality of antenna elements two-dimensionally arranged along a first axis and a second axis, A radio wave source, A phase adjustment unit provided between the array antenna and the radio wave source, for adjusting the phase of a transmission signal supplied from the radio wave source to the plurality of antenna elements in the first axis direction, An image acquisition unit that acquires an image through a fisheye lens, A position derivation unit that converts a first position of a marker included in an image acquired by the image acquisition unit with respect to the image acquisition unit into a second position in polar coordinates on a first plane including a first axis and a second axis, Based on the second position, an elevation angle acquisition unit that acquires a first elevation angle with respect to a third axis in the second plane of a projection position obtained by projecting the first position onto a second plane including the first axis and a third axis, A distance estimation unit that estimates a distance between the image acquisition unit and the marker, A control unit that controls the phase adjustment unit based on the first elevation angle acquired by the elevation angle acquisition unit and the distance in the third axis direction estimated by the distance estimation unit including The distance estimation unit Based on the coordinates of the upper end of the marker included in the image obtained from the second elevation angle with respect to the third axis and the azimuth angle with respect to the first axis, the coordinates of the lower end of the marker included in the image obtained from the third elevation angle with respect to the third axis and the azimuth angle with respect to the first axis, and the length between the upper end and the lower end, estimate the distance in the first axis direction between the image acquisition unit and the marker. A power supply device that estimates the distance in the third axis direction between the image acquisition unit and the marker based on the first elevation angle acquired by the elevation angle acquisition unit and the estimated distance in the first axis direction. **Claim 16** An array antenna having a plurality of antenna elements two-dimensionally arranged along a first axis and a second axis; A radio wave source; A phase adjustment unit provided between the array antenna and the radio wave source, for adjusting the phase of the power transmission signal supplied from the radio wave source to the plurality of antenna elements in the first axis direction; An image acquisition unit that acquires an image through a fish-eye lens; A position derivation unit that converts the first position of the marker included in the image acquired by the image acquisition unit with respect to the image acquisition unit into a second position in polar coordinates on a first plane including the first axis and the second axis; An elevation angle acquisition unit that acquires a first elevation angle with respect to the third axis within the second plane of the projection position obtained by projecting the first position onto a second plane including the first axis and the third axis based on the second position; In a power supply device including: Based on the coordinates of the upper end of the marker included in the image obtained from the second elevation angle with respect to the third axis and the azimuth angle with respect to the first axis, the coordinates of the lower end of the marker included in the image obtained from the third elevation angle with respect to the third axis and the azimuth angle with respect to the first axis, and the length between the upper end and the lower end, estimate the distance in the first axis direction between the image acquisition unit and the marker. Estimate the distance in the third axis direction between the image acquisition unit and the marker based on the first elevation angle acquired by the elevation angle acquisition unit and the estimated distance in the first axis direction. A power supply method for controlling the phase adjustment unit based on the first elevation angle acquired by the elevation angle acquisition unit and the estimated distance in the third axis direction.

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