JP2017051071A - Mobile device and non-contact power transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mobile device for performing non-contact power transmission advantageous in downsizing the device.SOLUTION: The mobile device movable on a track includes: a power reception antenna for receiving power in a non-contact manner from a transmission antenna disposed on the track; and a control unit for controlling moving and stopping of the mobile device. The transmission antenna is so configured that a coupling state with the power reception antenna changes at a predetermined interval along the track. The control unit controls stopping of the mobile device on the basis of the coupling state.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a technology for transmitting and receiving power in a contactless manner.

  Since MIT (Massachusetts Institute of Technology) conducted a demonstration experiment of non-contact power transmission by magnetic resonance in 2007, wireless power transmission technology has been widely researched and developed.

  Patent Document 1 discloses a technique for receiving power supply in a non-contact manner while a moving body such as an electric vehicle is moving on a traveling path. In Patent Document 1, a moving body includes a power transmission antenna that receives power from a power feeding antenna on a traveling road and a position detection antenna that is induced by a marker on the traveling road.

JP, 2014-082805, A

  However, in the technique of Patent Document 1, the moving body needs to include two power receiving antennas. Mounting a plurality of power receiving antennas is disadvantageous when downsizing of the moving body is required.

  An object of the present invention is to provide a mobile device that performs non-contact power transmission, which is advantageous in terms of downsizing the device, for example.

  According to one aspect of the present invention, there is provided a mobile device capable of moving along a traveling path, a power receiving antenna that receives power in a non-contact manner from a power transmission antenna disposed on the traveling path, and movement and stop of the mobile device. The power transmission antenna is configured such that a coupling state with the power receiving antenna varies at a predetermined interval along the traveling path, and the control unit is in the coupling state. On the basis of this, the mobile device is controlled to stop the mobile device.

  ADVANTAGE OF THE INVENTION According to this invention, the mobile apparatus which performs non-contact electric power transmission which is advantageous at the point of size reduction of an apparatus can be provided, for example.

The figure which shows the structural example of the non-contact electric power transmission system which concerns on embodiment. The figure which shows the structural example of the power transmission antenna and power receiving antenna in embodiment. The graph showing the relationship between the position of a receiving antenna and a coupling coefficient. The flowchart which shows the process from the movement start of a trolley | bogie to stopping in 1st Embodiment. The flowchart which shows the process from the movement start of a trolley | bogie to stopping in 2nd Embodiment. The figure which shows another structural example of a power transmission antenna.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment, It shows only the specific example advantageous for implementation of this invention. Moreover, not all combinations of features described in the following embodiments are indispensable for solving the problems of the present invention.

<First Embodiment>
In the present embodiment, an example is shown in which the present invention is applied to an automatic conveyance system that conveys a package using an automatic guided vehicle (AGV). Such an automatic conveyance system can be used in a factory or the like. The AGV has a rechargeable battery for driving.

  As a method for charging the battery of the AGV, a method in which the AGV stops after moving to the charging spot and charges the battery is common. However, in this method, since the time when the AGV does not travel occurs, it is necessary for another AGV to perform the conveyance of the load during that time or to be performed by a person. On the other hand, this embodiment employs a non-contact power transmission system that performs non-contact power feeding during movement for transmitting power while the AGV is traveling.

  The AGV needs to stop at a specified point in order to carry a package. Therefore, the AGV stops by detecting a magnetic marker laid on the floor surface, for example. Conventionally, on the AGV side, it is necessary to mount an antenna for receiving power and an antenna for detecting a magnetic marker. Since a plurality of antennas are mounted, it is not suitable for reducing the weight and size of the AGV body. Furthermore, when laying an antenna for power transmission on the floor surface, laying a magnetic marker may cause magnetic interference and deteriorate antenna characteristics. It is also necessary to change the position of the magnetic marker every time the travel location changes. Therefore, in the present embodiment, a system is realized in which power is transmitted using only a pair of power transmitting and receiving antennas, and the position where the AGV stops is detected and stopped.

  FIG. 1 shows a schematic diagram of a non-contact power transmission system according to the present embodiment. The non-contact power transmission system includes a power transmission unit 101 arranged along a travel path 10 extending in the X direction, and a carriage 102 (mobile device) that can move on the travel path 10. The carriage 102 includes a power reception unit 103. The power transmission unit 101 disposed on the travel path 10 includes a power transmission antenna 201, and the carriage 102 includes a power reception antenna 202 that receives power from the power transmission antenna 201. Further, the carriage 102 includes a first storage unit 104 and a second storage unit 105 that store various data, and a control unit 106 that controls movement and stopping of the carriage 102.

  FIG. 2 is a diagram illustrating a configuration example of the power transmission antenna 201 and the power reception antenna 202 in the present embodiment. The power transmission antenna 201 is configured such that the electromagnetic coupling state with the power reception antenna 202 varies periodically along the traveling path 10. For example, the power transmission antenna 201 is an 8-shaped antenna wired in an 8-shape along the traveling path 10 extending in the X direction, as illustrated. A large-sized antenna in a large-scale system such as an automatic conveyance system in a factory is required to have a leaking magnetic field as small as possible. In this regard, the figure-8 antenna is a low-leakage antenna. The principle will be described. When an alternating current is passed through the figure-8 antenna, the directions of the currents flowing through the ring 2011 and the ring 2022 are different. Specifically, when a clockwise current flows through the ring 2011, a counterclockwise current flows through the ring 2022. As a result, the generated magnetic fields cancel each other out, resulting in a low-leakage antenna. If the direction of the magnetic field generated by the adjacent annular conductors is different, it will meander in the direction of the traveling path 10 as shown in FIG. 6, for example, instead of the 8-shaped antenna. A meander-type antenna wired to the cable may be used.

  As the power receiving antenna 202, for example, a spiral antenna as shown in FIG. 2 is used. For example, a helical antenna may be used instead of the spiral antenna.

  As described above, the power transmitting antenna 201 is configured such that the electromagnetic coupling state with the power receiving antenna 202 varies periodically along the traveling path 10. The control unit 106 calculates or acquires a coupling coefficient between the power transmitting antenna 201 and the power receiving antenna 202 for each position of the mobile device on the travel path 10 as representing the coupling state. In the configuration of the power transmission / reception antenna of FIG. 2, the coupling coefficient representing the coupling state between the power transmission antenna and the power reception antenna when the power reception antenna 202 moves in the positive direction from the point X = 0 by the movement of the carriage 102 is as shown in FIG. It looks like the graph of In FIG. 3, the horizontal axis indicates the position of the power receiving antenna in the X direction, and the vertical axis indicates the coupling coefficient between the power transmitting antenna and the power receiving antenna. As can be seen from FIG. 3, there is a “null point” corresponding to a minimum value at which the coupling coefficient is almost zero at a constant period. The control unit 106 identifies the position of the carriage 102 by detecting this null point, and controls the running and stopping of the carriage 102.

  FIG. 4 is a flowchart showing processing by the control unit 106 from the start of movement of the carriage 102 to the stop thereof. First, before the carriage 102 starts moving, the first storage unit 104 stores in advance a predetermined value N (N is an integer equal to or greater than 1) indicating the number of null points that should be detected before the vehicle stops. Yes. Further, 0 is stored in the second storage unit 105 as an initial value of the count value m indicating the number of times the null point has been detected (S1). Thereafter, the carriage 102 starts moving on the travel path 10 (that is, on the power transmission antenna 201) (S2). If the null point is detected while the carriage 102 is moving (S3), “1” is added (incremented) to the count value m stored in the second storage unit 105 (S4). Next, it is determined whether the count value m stored in the second storage unit 105 is smaller than N−1 (S5). If the count value m is smaller than N-1, the running is continued and the process returns to S3. When the count value m becomes the same as N-1, deceleration is started (S6). The carriage 102 detects the Nth null point in the deceleration traveling (S7). Here, the count value m is incremented (S8). Thereafter, the carriage 102 stops (S9). Finally, the carriage 102 resets the count value m of the second storage unit 105 to the initial value “0” in preparation for the next conveyance.

  According to the above-described embodiment, the carriage 102 which is a mobile device need only include one power receiving antenna 202 corresponding to the power transmitting antenna 201 arranged on the travel path 10. In other words, the carriage 102 can be realized with a smaller number of power receiving antennas (power receiving coils) than the prior art, which is advantageous in reducing the size of the apparatus. In the above-described embodiment, the example in which the power transmission antenna 201 is configured so that the electromagnetic coupling state between the power transmission antenna 201 and the power reception antenna 202 is periodically changed has been described. In other words, the power transmission antenna 201 may be configured so that the coupling state between the power transmission antenna 201 and the power reception antenna 202 varies at a predetermined interval. The predetermined interval is not limited to a fixed interval.

Second Embodiment
In the first embodiment, the configuration when the carriage 102 has two storage units has been described. In the present embodiment, it will be described that even if the carriage 102 has only one storage unit, the carriage, which is a mobile device, can detect the stop position by itself using the power transmission / reception antenna and can stop. The system configuration in this embodiment is the same as that in FIG. 1, but it is assumed that the carriage 102 has the first storage unit 104 but does not have the second storage unit 105. FIG. 5 shows a flowchart of the process from the start of movement of the carriage 102 to the stop thereof in the present embodiment. The first storage unit 104 stores a count value n indicating the remaining number of null points to be detected during movement. First, before the carriage 102 starts moving, the count value n is set to the total number N of null points to be detected during movement (n = N) (S11). Thereafter, the carriage 102 starts moving on the power transmission antenna (S12). When a null point is detected (S13), “1” is subtracted (decremented) from the count value n stored in the first storage unit 104 (S14). Next, it is determined whether the count value n is greater than 1 (S15). If the count value n is greater than 1, the running is continued, and the process returns to S13. When the count value n becomes 1, deceleration is started (S16). Thereafter, the carriage 102 stops in response to detecting the last null point. Finally, the carriage 102 sets the count value n of the first storage unit 104 to “N” in preparation for the next conveyance.

  As described above, according to this embodiment, even when the carriage has only one storage unit, the carriage, which is a mobile device, can detect the stop position by itself using the power transmission / reception antenna and can stop. is there.

  In each of the above-described embodiments, the carriage stop control is performed based on the value of the coupling coefficient of the transmission / reception antenna. However, the present invention is not limited to this, and represents the coupling state of other transmission / reception antennas. An indicator may be used. For example, the carriage stop control may be performed based on the power consumed on the power receiving side, the current detected on the power receiving side, or the voltage instead of the coupling coefficient.

Further, in each of the above-described embodiments, the stop position of the carriage is detected by counting the number of detections of the null point that takes the minimum value at which the coupling coefficient value of the power transmission / reception antenna is approximately zero. However, as shown in the graph of FIG. 3, points other than the null point can also be observed periodically. The position of the carriage can be specified by the number of times the extreme value is detected. As the extreme value, a minimum value, a maximum value, or both can be used. For example, the stop position of the carriage may be detected by counting points that are not the local minimum value corresponding to the null point but the local maximum value.
In each of the above-described embodiments, the value of the coupling coefficient of the power transmission / reception antenna is periodically changed with a constant interval, but it is not necessary to have a constant interval.

(Other embodiments)
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

101: power transmission unit, 102: carriage (mobile device), 103: power reception unit, 104: first storage unit, 105: second storage unit, 106: control unit, 201: power transmission antenna, 202: power reception antenna

Claims (11)

A mobile device capable of moving along a traveling path,
A power receiving antenna for receiving power in a non-contact manner from a power transmitting antenna disposed on the road;
A control unit that controls movement and stop of the mobile device;
Have
The power transmitting antenna is configured such that a coupling state with the power receiving antenna varies at a predetermined interval along the traveling path,
The said control part controls the stop of the said mobile body apparatus based on the said connection state, The mobile body apparatus characterized by the above-mentioned.   The mobile device according to claim 1, wherein the control unit specifies a position of the mobile device by detecting an extreme value in the change in the coupling state.   The mobile unit according to claim 2, wherein the control unit stops the mobile unit when the number of detected extreme values during the movement of the mobile unit reaches a predetermined value N. apparatus.   The said control part starts deceleration of the said mobile device, when the number which detected the said extreme value during the movement of the said mobile device becomes the said predetermined value N-1. A mobile device according to claim 1.   The mobile device according to any one of claims 2 to 4, wherein the extreme value is a local minimum value in the change of the coupled state.   5. The mobile device according to claim 2, wherein the extreme value is a local maximum value in the variation of the combined state. 6.   The said control part acquires the coupling coefficient between the said power transmission antenna and the said power receiving antenna for every position of the said mobile body apparatus in the said travel path as a parameter | index showing the said coupling state. The mobile body device according to any one of 1 to 6.   The said control part acquires the electric power, electric current, or voltage detected with the said receiving antenna for every position of the said mobile body apparatus in the said travel path as a parameter | index showing the said coupling state. The mobile body device according to any one of 1 to 6.   The mobile device according to any one of claims 1 to 8, wherein the power transmission antenna is an 8-shaped antenna wired in an 8-shape along the traveling path.   The mobile device according to any one of claims 1 to 8, wherein the power transmission antenna is a meander antenna wired so as to meander with respect to the direction of the travel path. A power transmission antenna disposed along the road;
A power receiving antenna that receives power from the power transmitting antenna in a non-contact manner, and a mobile device capable of moving along the travel path;
A contactless power transmission system comprising:
The power transmitting antenna is configured such that a coupling state with the power receiving antenna varies at a predetermined interval along the traveling path,
The mobile device has a control unit that controls movement and stop of the mobile device,
The said control part controls the stop of the said mobile body apparatus based on the said connection state, The non-contact electric power transmission system characterized by the above-mentioned.

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