JP7472523B2 - Mobile charging system - Google Patents

Description

The present invention relates to a mobile body charging system that charges a mobile body that moves using power stored in a storage battery from a charging device.

Conventionally, a device for charging an autonomous flying object such as a drone is described in Patent Document 1. The flying object power supply device described in Patent Document 1 has a landing pad on which the drone lands and a power transmission unit provided below the center of the landing pad. A power receiving coil is provided at the bottom of the drone, and this power receiving coil faces and electromagnetically couples with the power transmission coil of the power transmission unit, thereby supplying power to the drone through electromagnetic induction. The landing pad has a sloped portion in the shape of a flat inverted truncated pyramid with the center set lower than the periphery, and when the drone lands on the sloped portion, the slope of the sloped portion guides the drone to the center. Then, the power receiving coil and the power transmission coil are precisely facing each other, enabling highly efficient power supply.

An automatic landing system for automatically landing an autonomous flying object at a target location is described in Patent Document 2. In this automatic landing system, the flying object is equipped with an imaging device mounted on the underside of the aircraft, and the positional relationship between the landing target and the flying object is calculated based on an image of the landing target acquired by the imaging device, and the landing of the flying object is controlled based on the result of this calculation.

JP 2017-124758 A JP 2012-071645 A

For example, even if the landing of an aircraft is controlled based on an image of the landing position captured by an imaging device as described in Patent Document 2, the landing position may deviate from the target position due to external disturbances such as wind. Also, while it may seem possible to guide the aircraft to the center of the landing pad by providing a slope on the landing pad as described in Patent Document 1, the slope of the slope must be large in order to reliably guide the aircraft to the center of the landing pad, and if the slope is large, there is a risk that the drone will stop at a position past the center.

Therefore, the present invention aims to provide a mobile body charging system that can accurately align the power receiving unit of the mobile body and the power transmitting unit of the charging device.

In order to achieve the above-mentioned object, the present invention provides a mobile body charging system in which a storage battery of a mobile body that moves using power stored in the storage battery is charged by a charging device, wherein the mobile body has a power receiving unit that receives power from the charging device and stores the power received by the power receiving unit in the storage battery, the charging device has a power transmitting unit connected to the power receiving unit and a moving unit capable of moving the power receiving unit to a position where it is connected to the power transmitting unit , and the moving unit has a plurality of electromagnets arranged around the power transmitting unit, and the power receiving unit is guided toward the power transmitting unit by the magnetic force of the plurality of electromagnets .

The mobile body charging system of the present invention makes it possible to accurately align the power receiving unit of the mobile body and the power transmitting unit of the charging device.

1A is a diagram showing the state in which the aircraft has landed on the landing pad of the charging device, and FIG. 1B is a cross-sectional view taken along line AA of FIG. 2 is a block diagram showing an example configuration of an aircraft, a charging device, and an operation terminal. FIG. (a) to (c) are overhead views of the landing pad.

[Embodiment]
A mobile charging system according to an embodiment of the present invention will be described with reference to Figures 1 to 3. The embodiment described below is shown as a preferred specific example for implementing the present invention, and although there are some parts that specifically exemplify various technical matters that are technically preferable, the technical scope of the present invention is not limited to this specific embodiment. In the following description, "upper" and "lower" refer to upper and lower in the vertical direction.

The mobile body charging system according to this embodiment is composed of an aircraft as a mobile body to be charged, and a charging device that charges the aircraft. FIG. 1(a) shows the state in which the aircraft 1 has landed on the landing pad 20 of the charging device 2. FIG. 1(b) is a cross-sectional view taken along line A-A in FIG. 1(a). FIG. 2 is a block diagram showing an example configuration of the aircraft 1 and charging device 2 in the mobile body charging system 100, as well as the operation terminal 3 with which an operator operates the aircraft 1. FIGS. 3(a) to (c) are bird's-eye views of the landing pad 20.

The flying object 1 is a so-called drone, and includes an airframe 11, first to fourth motors 121 to 124 mounted on the airframe 11, first to fourth propellers 131 to 134 rotated and driven by the first to fourth motors 121 to 124, a first communication unit 141 that performs wireless communication with the operation terminal 3, a second communication unit 142 that performs wireless communication with the charging device 2, a position detection unit 15 that detects the position of the reference position of the airframe 11 (for example, the center of the torso 110) using a GPS signal transmitted from a GPS (Global Positioning System) satellite, for example, an imaging device 16 that images the area below the airframe 11, a current output unit 17 that outputs motor currents to the first to fourth motors 121 to 124, a control unit 18 that adjusts the motor currents output from the current output unit 17 to the first to fourth motors 121 to 124 to control the first to fourth motors 121 to 124, and a power supply unit 19.

The aircraft 11 comprises a torso 110, four arms 111-114 extending radially from the torso 110, a number of legs 115 extending downward from the torso 110, and a holder 116 that holds a power receiving unit 191 (described below). The first to fourth motors 121-124 are housed in each of the four arms 111-114, and the first to fourth propellers 131-134 are disposed above the tips of the four arms 111-114. The number of arms, motors, and propellers is not limited to four, and may be five or more.

The power supply unit 19 includes a power receiving section 191 that receives power from the charging device 2 by inductive power supply, a rectifier circuit 192 that rectifies the AC current generated by the power receiving section 191, a storage battery 193, and a charging circuit 194 that charges the storage battery 193 with the voltage rectified by the rectifier circuit 192. The storage battery 193 is, for example, a secondary battery such as a lithium ion battery or a nickel-metal hydride battery, or a large-capacity capacitor, and stores the power received by the power receiving section 191. The power stored in the storage battery 193 is supplied to the current output section 17 and used to drive the first to fourth motors 121 to 124. In other words, the aircraft 1 moves (flies) using the power stored in the storage battery 193.

The power receiving unit 191 has a core material 191a made of a soft magnetic material and a power receiving coil 191b arranged around the core material 191a. A metal with high magnetic permeability such as iron can be suitably used as the core material 191a. The power receiving coil 191b is formed by winding a conductor made of, for example, an enameled wire around the core material 191a. In this embodiment, the core material 191a is cylindrical and arranged so that its axial direction is along the vertical direction. As shown in FIG. 1(b), the power receiving unit 191 is accommodated in the holding unit 116 of the machine body 11. The holding unit 116 is a bottomed cylinder having a cylindrical cylindrical portion 116a and a disk-shaped bottom portion 116b, and the lower end surface of the core material 191a faces the bottom portion 116b.

The charging device 2 has a landing pad 20 on which the flying object 1 lands, a power transmission unit 21 that is placed at the center of the landing pad 20 and connected to the power receiving unit 191 of the flying object 1, a power transmission power supply unit 22 that generates a voltage to be supplied to the power transmission unit 21 by, for example, converting the voltage and frequency of a commercial power source, a moving unit 23 that can move the power receiving unit 191 to a position where it is connected to the power transmission unit 21, a communication unit 24 that performs wireless communication with the flying object 1, and a control unit 25 that controls the power transmission power supply unit 22 and the moving unit 23 based on information obtained by wireless communication with the flying object 1.

Like the power receiving unit 191, the power transmitting unit 21 has a core material 21a made of a soft magnetic material and a power transmitting coil 21b arranged around the core material 21a. The core material 21a of the power transmitting unit 21 is cylindrical and has the same diameter as the core material 191a of the power receiving unit 191, for example.

As shown in Figures 3(a) to (c), the moving unit 23 has multiple electromagnets 230 arranged around the power transmission unit 21. As shown in Figure 1(b), each electromagnet 230 has a core material 230a made of a soft magnetic material and a coil 230b arranged around the core material 230a. The magnetic force of the electromagnets 230 acts on the core material 191a, and the power receiving unit 191 of the aircraft 1 is guided to the power transmission unit 21 side by the magnetic force of the electromagnets 230.

In this embodiment, the moving unit 23 has a first annular band 23a consisting of a plurality of electromagnets 230 arranged to surround the power transmission unit 21, and a second annular band 23b consisting of a plurality of electromagnets 230 arranged to surround the outside of the first annular band 23a. In Figures 3(a) to (c), the first annular band 23a and the second annular band 23b are each shown surrounded by a dashed line. Hereinafter, among the plurality of electromagnets 230, the plurality of electromagnets 230 constituting the first annular band 23a may be referred to as first electromagnets 231, and the plurality of electromagnets 230 constituting the second annular band 23b may be referred to as second electromagnets 232. In the example shown in Figures 3(a) to (c), the first annular band 23a is constituted by four first electromagnets 231, and the second annular band 23b is constituted by eight second electromagnets 232.

The landing pad 20 has a surface plate 201 and a base plate 202 arranged below the surface plate 201. The landing pad 20 is formed with a power transmission unit housing 20a that houses the power transmission unit 21, and multiple electromagnet housings 20b that each house multiple electromagnets 230. The power transmission unit housing 20a and the electromagnet housing 20b penetrate the surface plate 201, and are partially formed in the base plate 202. The depth of the power transmission unit housing 20a is a height at which the height of the upper end surface of the core material 21a of the power transmission unit 21 coincides with the surface 201a of the surface plate 201. The depth of the electromagnet housing 20b is a height at which the height of the upper end surface of the core material 230a of the electromagnet 230 coincides with the surface 201a of the surface plate 201.

When the control unit 25 detects through wireless communication with the aircraft 1 that the aircraft 1 has landed on the landing pad 20, it controls the movement unit 23 to guide the aircraft 1 to a position where the power receiving unit 191 and the power transmitting unit 21 are connected, and then controls the power transmission power supply unit 22 to generate a high-frequency voltage and supply power to the aircraft 1.

The operation terminal 3 has an operation unit 31 that accepts operations from an operator, a communication unit 32 that communicates with the first communication unit 141 of the aircraft 1, and a communication control unit 33 that generates instruction information to be sent to the aircraft 1 based on the contents of the operation accepted by the operation unit 31 and controls the communication unit 32 to communicate with the aircraft 1. The operation unit 31 has switches and operation levers for accepting instruction operations from the operator, such as the flight direction and flight speed of the aircraft 1, stopping in the air (hovering), and landing on the landing pad 20.

Instruction information indicating the content of the operation received by the operation terminal 3 from the operator is transmitted from the communication unit 32 of the operation terminal 3 to the first communication unit 141 of the aircraft 1, and the control unit 18 of the aircraft 1 controls the first to fourth motors 121 to 124 based on the instruction information. When the operator instructs landing on the landing pad 20, the control unit 18 of the aircraft 1 controls the first to fourth motors 121 to 124 based on information obtained from the position detection unit 15 and the imaging device 16 so that the aircraft 1 lands on the landing pad 20 by autonomous flight. The target position for this landing is the center of the landing pad 20, and more specifically, the position where the core material 191a of the power receiving unit 191 and the core material 21a of the power transmitting unit 21 are aligned coaxially as shown in FIG. 1(b).

However, the landing position of the aircraft 1 may deviate from the center of the landing pad 20 due to, for example, external disturbances such as wind, or the impact of the legs 115 of the aircraft 1 hitting the landing pad 20 causing the aircraft 1 to bounce. In addition, when an operator operates the operation terminal 3 to land the aircraft 1 on the landing pad 20, the landing position of the aircraft 1 may also deviate from the center of the landing pad 20 due to the operator's poor operating skills.

The efficiency of power transmission from the power transmission unit 21 to the power receiving unit 191 is highest when the core material 191a of the power receiving unit 191 and the core material 21a of the power transmission unit 21 are aligned on the same axis. If the position of the power receiving unit 191 deviates from this ideal position, losses increase and the power transmission efficiency decreases. Furthermore, if the power receiving unit 191 deviates significantly from the power transmission unit 21, power cannot be transmitted from the power transmission unit 21 to the power receiving unit 191. For this reason, if the aircraft 1 lands in a position that is different from the ideal position, it is desirable to move the aircraft 1 so that the center position of the core material 191a of the power receiving unit 191 and the center position of the core material 21a of the power transmission unit 21 approach each other.

In this embodiment, the control unit 25 of the charging device 2 controls the moving unit 23 to move the aircraft 1 after landing so that the central axis of the core material 191a of the power receiving unit 191 coincides with the central axis of the core material 21a of the power transmitting unit 21. Next, the operation of this moving unit 23 will be described with reference to Figures 3(a) to (c).

In Figures 3(a) and (b), cross-hatching is applied to the upper end surface of the core material 230a of the electromagnet 230 in which current is passed through the coil 230b among the multiple electromagnets 230. Also, in Figure 3(c), cross-hatching is applied to the upper end surface of the core material 21a of the power transmission unit 21 in which current is passed through the power transmission coil 21b.

When the control unit 25 of the charging device 2 detects that the aircraft 1 has landed on the landing pad 20 by communicating with the aircraft 1 via the communication unit 24, it energizes the coils 230b of the multiple second electromagnets 232 of the second annular belt 23b. As a result, even if the aircraft 1 lands on the landing pad 20 with the power receiving unit 191 positioned outside the second annular belt 23b, the aircraft 1 moves closer to the center of the landing pad 20 due to the magnetic force of the second electromagnets 232. During this movement, the legs 115 of the aircraft 1 glide on the surface 201a of the surface plate 201. The control unit 25 continues to supply current to the second electromagnets 232 for a predetermined time (e.g., one second or more) that takes into account the time required for the aircraft 1 to move, and then stops supplying current to the second electromagnets 232.

Then, the control unit 25 of the charging device 2 cuts off the current supply to the second electromagnet 232, and then energizes the coils 230a of the multiple first electromagnets 231 in the first annular band 23a. This causes the magnetic force of the first electromagnets 231 to move the aircraft 1 closer to the center of the landing pad 20. The control unit 25 also continues to supply current to the first electromagnets 231 for a predetermined time, and then stops the current supply to the first electromagnets 231.

Next, the control unit 25 of the charging device 2 cuts off the current supply to the first electromagnet 231, and then controls the power supply unit 22 to supply current to the power transmission coil 21b of the power transmission unit 21 for a predetermined time. This current is an excitation current for generating a magnetic force in the power transmission unit 21 to attract the core material 191a of the power receiving unit 191, and the frequency of the voltage is not limited to the high frequency used when inductively feeding power to the power receiving unit 191, and may be, for example, direct current.

Then, the control unit 25 of the charging device 2 controls the power transmission power supply unit 22 to supply high-frequency current to the power transmission coil 21b of the power transmission unit 21, and performs inductive power supply to the power receiving unit 191. This charges the storage battery 193 of the aircraft 1. Furthermore, when the control unit 25 detects through communication with the aircraft 1 via the communication unit 24 that charging of the storage battery 193 is complete, it stops supplying high-frequency current to the power transmission coil 21b.

(Functions and Effects of the Embodiments)
According to the embodiment of the present invention described above, the flying object 1 is moved so that the power receiving unit 191 approaches the power transmitting unit 21 by the magnetic force acting on the core material 191a of the power receiving unit 191, so that the power receiving unit 191 and the power transmitting unit 21 can be accurately aligned. Then, inductive power supply from the power transmitting unit 21 to the power receiving unit 191 is started after the power receiving unit 191 and the power transmitting unit 21 are aligned, so that power can be supplied to the flying object 1 with high efficiency.

(Additional Note)
Although the present invention has been described above based on the embodiment, the invention according to the claims is not limited to the embodiment. It should be noted that not all of the combinations of features described in the embodiment are necessarily essential to the means for solving the problems of the invention.

The present invention can be modified as appropriate by omitting some of the components or adding or replacing components without departing from the spirit of the invention. For example, in the above embodiment, the mobile object to be charged is an airborne object, but the present invention is not limited to this, and the mobile object charging system can also be applied to cases where a mobile object moving on land or water is to be charged.

In the above embodiment, the case where inductive power is supplied from the power transmitting unit 21 to the power receiving unit 191 has been described, but this is not limiting, and power may be supplied, for example, by electrical coupling caused by contact between contacts.

In the above embodiment, the multiple electromagnets 230 are arranged so that the first annular band 23a and the second annular band 23b are concentric circular bands. However, this is not limiting. For example, a rectangular first annular band may be formed by some of the multiple electromagnets arranged in a lattice pattern, and a rectangular second annular band larger than the first annular band may be formed by other electromagnets. Also, a third annular band may be added outside the second annular band, and a fourth annular band may be further added outside that.

In the above embodiment, the power receiving unit 911 is held by the holding unit 116 of the aircraft 11, but the power receiving unit 911 may be supported in a floating manner so that it can move horizontally relative to the aircraft 11. In this case, it is not necessary to move the entire aircraft 1 on the landing pad 20, making it easier to align the power receiving unit 191 and the power transmitting unit 21.

Furthermore, in the above embodiment, the legs 115 slide along the surface 201a of the surface plate 201 when the aircraft 1 moves on the landing pad 20, but to make it easier to move the aircraft 1, casters with rolling wheels may be attached to the tips of the legs 115.

100... Mobile body charging system 1... Flying body (mobile body)
191: power receiving section 191a: core material 191b: power receiving coil 193: storage battery 2: charging device 21: power transmitting section 21a: core material 21b: power transmitting coil 23: moving section 23a: first annular band 23b: second annular band 230: electromagnet

Claims (4)

A mobile body charging system that charges a storage battery of a mobile body that moves using electric power stored in the storage battery from a charging device,
the moving body has a power receiving unit that receives power from the charging device, and stores the power received by the power receiving unit in the storage battery;
the charging device includes a power transmitting unit coupled to the power receiving unit, and a moving unit capable of moving the power receiving unit to a position where the power receiving unit is coupled to the power transmitting unit;
the moving unit includes a plurality of electromagnets arranged around the power transmitting unit,
The power receiving unit is guided to the power transmitting unit by the magnetic forces of the multiple electromagnets.
Mobile charging system. The power receiving unit and the power transmitting unit each have a core material made of a soft magnetic material and a coil disposed around the core material,
The magnetic force acts on the core material of the power receiving portion.
The mobile charging system according to claim 1 . the plurality of electromagnets include a plurality of first electromagnets that form a first annular band that surrounds the power transmitting unit, and a plurality of second electromagnets that form a second annular band that surrounds the outside of the first annular band,
After energizing the second electromagnets in the second annular band, energizing the first electromagnets in the first annular band, and then energizing the coil of the power transmission unit.
The mobile charging system according to claim 2 . The moving object is an aircraft capable of autonomous flight.
The mobile charging system according to any one of claims 1 to 3 .

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