JP6950632B2 - Power transmission device that supplies power wirelessly and foreign matter detection method - Google Patents

Description

The present invention relates to a device for detecting the entry of a foreign substance such as a person in a predetermined detection range including a power transmission range in wireless power transmission.

In the technology of supplying power to a target by wireless power transmission, there is a concern about the influence of radio waves on a person when a person enters the power transmission area when transmitting a large amount of power. For this reason, conventionally, in wireless power transmission technology, it is detected whether or not an object such as a person has entered a predetermined area, and when the entry is detected, the power transmission is stopped.

For example, in the power transmission system of Patent Document 1, a radio wave is transmitted to a detection range, the reflected wave of the transmitted radio wave is received by a plurality of receiving units, and information on the phase difference of the reflected wave received by the plurality of receiving units is used. As a result, the presence of foreign matter is detected, and when the foreign matter is detected, power transmission is stopped.

Japanese Unexamined Patent Publication No. 2014-207949

When the detection technology as in Patent Document 1 is applied to an environment in which a moving robot exists, such as a factory, the moving robot may enter the detection range, and in that case, the robot is mistaken as a foreign substance. There is a problem of detecting it.

The present invention is a device that wirelessly transmits electric power, and is a power transmission device that detects that a foreign substance such as a person has entered a predetermined detection range without erroneously detecting a normally moving object such as a robot. offer.

In the first aspect of the present disclosure, there is provided a power transmission device that wirelessly supplies electric power to a power receiving device in an environment in which robots that move in a plurality of operation patterns are arranged. The power transmission device is an array antenna equipped with a plurality of antenna elements for transmitting radio waves for supplying power, and information indicating the state of the radio wave propagation environment within a predetermined detection range, and foreign matter is contained within the detection range. Propagation of radio waves in the detection range obtained in advance based on the signal received by the array antenna in the non-existent state and after obtaining the first environmental information and then obtained by the signal received by the array antenna. It includes a control unit that detects the intrusion of foreign matter in the detection range based on the second environmental information indicating the state of the environment. The first environmental information is obtained for each operation pattern, and includes a change in the state of the radio wave propagation environment at regular intervals when the robot operates in each operation pattern. The control unit obtains the second environmental information based on the signal received by the array antenna, acquires the operation pattern of the robot when the second environmental information is obtained, and is constant when the robot operates according to the acquired operation pattern. Presence or absence of foreign matter in the detection range based on the result of comparison between the second environmental information and the acquired first environmental information after acquiring the first environmental information including the change in the state of the radio wave propagation environment every hour. Is detected.

In the second aspect of the present disclosure, a wireless power transmission system including the above-mentioned power transmission device and a power receiving device that receives power wirelessly from the power transmission device is provided.

In a third aspect of the present disclosure, there is provided a method for detecting foreign matter in a wireless power system used in an environment in which robots that move in a plurality of motion patterns are arranged. The foreign matter detection method is information that transmits radio waves for supplying power through an array antenna provided with a plurality of antenna elements and indicates the state of the radio wave propagation environment within the detection range by the control unit. The first environmental information is obtained in advance based on the signal received by the array antenna in a state where no foreign matter exists within the range. The first environmental information is obtained for each operation pattern, and includes a change in the state of the radio wave propagation environment at regular intervals when the robot operates in each operation pattern. When the control unit obtains the first environmental information, then obtains the second environmental information indicating the state of the radio wave propagation environment in the detection range based on the signal received by the array antenna, and obtains the second environmental information. The first environmental information including the change in the state of the radio wave propagation environment at regular intervals when the robot operates according to the acquired motion pattern is acquired, and the acquired first environment information is acquired. Is compared with the second environmental information, and the presence or absence of foreign matter in the detection range is detected based on the comparison result.

In a fourth aspect of the present disclosure, there is provided a foreign matter detecting device that detects the entry of foreign matter within a predetermined detection range in an environment in which robots that move in a plurality of motion patterns are arranged. The foreign matter detection device is an array antenna equipped with a plurality of antenna elements that transmit radio waves in the detection range, and information indicating the state of the radio wave propagation environment in the detection range, and is an array in a state where no foreign matter exists in the detection range. The first environmental information obtained in advance based on the signal received by the antenna and the state of the radio wave propagation environment in the detection range obtained based on the signal received by the array antenna after obtaining the first environmental information are shown. It is provided with a control unit that detects the entry of foreign matter in the detection range based on the environmental information of 2. The first environmental information is obtained for each operation pattern, and includes a change in the state of the radio wave propagation environment at regular intervals when the robot operates in each operation pattern. The control unit obtains the second environmental information based on the signal received by the array antenna, acquires the operation pattern of the robot when the second environmental information is obtained, and is constant when the robot operates according to the acquired operation pattern. The first environmental information including the change in the state of the radio wave propagation environment every hour is acquired, and the presence or absence of foreign matter in the detection range is determined based on the comparison result between the acquired first environmental information and the second environmental information. To detect.

According to the present invention, the entry of a foreign substance such as a person into the detection range is detected based on the difference from the environmental information indicating a normal environmental state in which no foreign substance exists. As a result, even if there is a moving object in a normal environment state, it is possible to prevent erroneous detection of the moving object, and it is possible to accurately detect the entry of a foreign substance into the detection range.

The figure which shows the example which applied the technique of the object detection apparatus which concerns on this invention to a wireless power transmission system. Block diagram showing the configuration of the wireless power transmission system according to the first embodiment of the present invention. Diagram explaining the measurement method of reference propagation environment data A diagram showing propagation environment data (reference propagation environment data) when there is no person in the detection range and propagation environment data when a person enters the detection range. Diagram showing an example of a propagation environment table Diagram explaining the measurement of propagation environment data in a wireless power transmission system A flowchart showing a measurement operation of reference propagation environment data in the wireless power transmission system of the first embodiment. A flowchart showing a foreign matter detection operation in the wireless power transmission system of the first embodiment. A block diagram showing a configuration of a wireless power transmission system according to a second embodiment of the present invention. A flowchart showing a measurement operation of reference propagation environment data in the wireless power transmission system of the second embodiment. A flowchart showing a foreign matter detection operation in the wireless power transmission system of the second embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

(Application example)
First, an example of a situation in which the foreign matter detection device according to the present disclosure is applied will be described. The foreign matter detection device according to the present disclosure can be applied to, for example, a wireless power transmission system used for wireless power transmission in a manufacturing factory.

FIG. 1 is a diagram showing an example in which the foreign matter detection device according to the present disclosure is applied to a wireless power transmission system. The wireless power transmission system 10 is a system that wirelessly transmits electric power to a device to be supplied with power. The wireless power transmission system 10 includes a power transmission device 100 and a power receiving device 200. The power transmission device 100 supplies electric power to the power receiving device 200 by, for example, microwaves. The power receiving device 200 receives microwaves from the power transmitting device 100 and operates on the power of the received microwaves. The power receiving device 200 is, for example, a sensor arranged in a manufacturing factory. The power transmission device 100 includes an array antenna 110 for power transmission. The array antenna 110 includes a plurality of antenna elements 112, and is capable of transmitting and receiving directional radio waves.

According to the wireless power transmission system 10, the power transmission device 100 transmits radio waves (microwaves) from the array antenna 110 to transmit power to a plurality of power receiving devices 200 within a predetermined power supply range P. Further, the power transmission device 100 receives the reflected wave from an object within a predetermined detection range S (details will be described later) including the power supply range P by the array antenna 110, and based on the received radio wave, the detection range at that time. Detects the radio wave propagation environment in the space inside S. Then, the power transmission device 100 detects whether or not a foreign substance has entered the detection range S based on the detected propagation environment. Here, the foreign matter is an object that is not originally arranged or does not exist in the detection range S during the operation of the wireless power transmission system 10, and is, for example, a person, an animal, or a moving machine.

When the power transmission device 100 detects the intrusion of a foreign substance such as a person 420, the power transmission device 100 either stops supplying power to the power receiving device 200 or performs a process of reducing the value of the transmitted power to a level that does not affect the human body. conduct. This makes it possible to reduce the influence of radio waves for power transmission on the human body and machines.

The propagation environment of radio waves in the space within the detection range S changes depending on whether a foreign substance such as a person 420 is present in the detection range S or not. Therefore, the power transmission device 100 detects the entry of foreign matter such as human 420 into the detection range S by utilizing the difference in the propagation environment between the presence and absence of foreign matter such as human 420. In this way, by utilizing the difference in the propagation environment between when a foreign object such as a person 420 exists in the detection range S and when it does not exist, a moving object such as a robot 400 exists in the detection range S. Even in this case, it is possible to accurately detect the entry of foreign matter into the detection range S.

(Embodiment 1)
Hereinafter, embodiments of the wireless power transmission system and the foreign matter detection device according to the present invention will be described with reference to the accompanying drawings.

1. 1. Configuration Figure 2 is a block diagram showing the configuration of the wireless power transmission system according to the first embodiment of the present disclosure. The wireless power transmission system 10 according to the first embodiment includes a power transmission device 100 that wirelessly transmits power, and a power receiving device 200 that receives power transmitted from the power transmission device 100.

The power transmission device 100 includes an array antenna 110 having directivity, a directional control unit 120 that controls the directivity of the array antenna, a power supply signal generation unit 130 that generates a power supply signal for transmitting power, and an array antenna 110. It includes a receiving unit 140 that receives radio waves indicating the propagation environment via the antenna, a control unit 150 that controls the operation of the power transmission device 100, and a memory 160 that stores a propagation environment table that indicates reference propagation environment data.

The array antenna 110 includes a plurality of antenna elements 112, and can realize desired radiation directivity. For example, in the array antenna 110, N antenna elements 112 (N is a natural number of 2 or more) are appropriately arranged, all or part of them are excited, and the amplitude and phase of the excitation current (voltage) are controlled. The desired radiation directivity (radiation pattern) can be obtained.

The power supply signal generation unit 130 is a circuit that generates a power supply signal for generating microwaves that carry electric power according to the control from the control unit 150. The power feeding signal generation unit 130 is, for example, a semiconductor oscillator such as a Gunn diode or a microwave oscillator such as a magnetron.

The directivity control unit 120 is a circuit that controls the directivity of the signal radiated from the array antenna 110 according to the control from the control unit 150, and supplies power to each antenna element 112 based on the power supply signal from the power supply signal generation unit 130. Generate a signal to do.

Specifically, the directional control unit 120 distributes the power supply signal generated by the power supply signal generation unit 130 to N power supply signals (microwaves). Further, the directivity control unit 120 individually adjusts the phase of each of the N feed signals. This function of the directivity control unit 120 can be realized by, for example, a phase shifter. Further, the directivity control unit 120 individually adjusts the amplitudes of N microwaves. This function of the directional control unit 120 can be realized by, for example, a power amplifier such as a variable gain amplifier.

The receiving unit 140 is a circuit that takes out a radio wave received via the array antenna 110 as an electric signal.

The control unit 150 controls the entire operation of the power transmission device 100, and realizes a predetermined function by executing a program, for example. The control unit 150 includes a CPU, RAM, ROM, and the like. The control unit 150 may include another type of general-purpose processor, for example, an MPU, instead of the CPU. Alternatively, instead of a CPU, a processor specially designed to realize a predetermined function may be used. That is, the control unit 150 can include various processors such as a CPU, MPU, GPU, DSP, FPGA, and ASIC.

The memory 160 is a recording medium for recording information, for example, a flash memory. The memory 160 may be another type of recording medium (for example, a hard disk, SSD) as long as it is a non-volatile recording medium. In particular, the memory 160 stores in advance the propagation environment data measured in an environment where no foreign matter such as a person exists in the detection range S (details will be described later).

The power receiving device 200 receives electric power from the power transmitting device 100 and is driven by the received electric power. The power receiving device 200 is, for example, a sensor. The power receiving device 200 includes an antenna 210 that receives radio waves indicating a power feeding signal, a receiving unit 220 that processes radio waves received by the antenna 210, and a control unit 230 that controls the operation of the power receiving device 200. The receiving unit 220 includes a circuit for generating electric power from the power feeding signal received by the antenna 210. The control unit 230 includes a control circuit that realizes the function of the power receiving device 200.

Further, the power transmission device 100 is connected to the control device 300 that controls the robot 400 via an interface circuit (not shown) for communicating with other devices.

2. Operation The operation of the wireless power transmission system 10 having the above configuration will be described below. In particular, the foreign matter detection operation in the wireless power transmission system 10 will be described below.

In the wireless power transmission system 10, the power transmission device 100 monitors the radio wave propagation environment in the space of the detection range S during power transmission, and whether a foreign substance such as a person has entered the detection range based on the state of the radio wave propagation environment. Detect whether or not. Here, the predetermined detection range S is a range in which the array antenna 110 can receive radio waves. The detection range S can be controlled by adjusting the sensitivity and directivity of the array antenna 110. The detection range S may be set to, for example, the same range as the power supply range P, or may be set to a range larger than that.

Therefore, in the wireless power transmission system 10 of the present embodiment, the propagation environment of radio waves in the space of the detection range S is measured in advance in a state where the robot 400 is normally operated in a state where there is no foreign matter such as a person. Hereinafter, information indicating the propagation environment of radio waves is referred to as "propagation environment data". In this embodiment, information indicating the Doppler effect is adopted as an example of the propagation environment data.

Specifically, as shown in FIG. 3, a state in which the robot 400 is normally operated and power is supplied to the power receiving device 200 (for example, a sensor) in an environment where there is no foreign matter such as a person in the detection range S (for example). In the "reference state"), the array antenna 110 receives radio waves from the surrounding environment. The radio wave received at this time is a reflected wave in which microwaves transmitted from the array antenna 110 for power transmission are reflected by a robot 400, a power receiving device 200, or the like in the space of the detection range S. Since the robot 400 is moving, this reflected wave also changes with time. FIG. 4 is a diagram showing an example of a change in the reflected wave received by the array antenna 110. The solid line A in FIG. 4 shows the waveform of the reflected wave received by the array antenna 110 in the reference state.

The propagation environment data (hereinafter referred to as "reference propagation environment data") obtained in the reference state as described above is stored in the memory 160 as a propagation environment table.

FIG. 5 is a diagram showing an example of a propagation environment table including reference propagation environment data. The robot 400 can operate in a plurality of operation patterns. The propagation environment table includes the operation pattern of the robot 400, the operation period (from the start time to the end time) of the operation pattern, and the reference propagation environment data measured during the operation of the operation pattern. The propagation environment data is data in which information indicating the Doppler effect is quantified. As described above, the reference propagation environment data is obtained for each operation pattern, and includes changes in the state of the radio wave propagation environment at regular intervals when the robot 400 operates in each operation pattern.

The power transmission device 100 receives reflected waves from the surrounding environment via the array antenna 110 during normal power transmission operation. The power transmission device 100 obtains propagation environment data from the received reflected wave.

For example, as shown in FIG. 6, when the person 420 enters the detection range S, the array antenna 110 receives the reflected wave from the person 420. Therefore, the radio wave received through the array antenna 110 is different from that measured in the reference state without the person 420. Therefore, for example, in FIG. 4, the waveform obtained in the reference state is the waveform shown by the solid line A, whereas when there is a person 420, the waveform is as shown by the broken line B, and both are different.

Therefore, the power transmission device 100 compares the propagation environment data obtained during normal power transmission operation with the reference propagation environment data obtained in advance in a reference state free of foreign matter such as humans, and detects the difference. Detects whether or not a foreign object such as a person has entered the detection range S.

Hereinafter, the measurement operation of the reference propagation environment data in the power transmission device 100 of the wireless power transmission system 10 of the present embodiment and the power transmission operation accompanied by the foreign matter detection operation will be described.

2.1 Measurement of reference propagation environment data FIG. 7 is a flowchart showing a measurement operation of reference propagation environment data in the power transmission device 100 of the wireless power transmission system 10. The process shown in FIG. 7 is performed in advance in the environment in which the wireless power transmission system 10 is installed before the start of the normal power transmission operation. Further, it is assumed that the robot 400 is arranged within the detection range S in the environment where the wireless power transmission system 10 is installed.

First, the control unit 150 of the power transmission device 100 starts a power supply operation to the power reception device 200 (S10). For this purpose, the control unit 150 sends a control signal indicating the power Pout_i, the phase θout_i, and the frequency fout to be input to each antenna element (i) 112 of the array antenna 110 to the power supply signal generation unit 130 and the directivity control unit 120. Send. The power supply signal generation unit 130 generates a power supply signal by microwaves having a frequency fout. The directivity control unit 120 modulates the power supply signal from the power supply signal generation unit 130, generates a power supply signal having power Pout_i, phase θout_i, and frequency fout for each antenna element (i) 112, and generates each antenna element (i). ) Send to 112. As a result, a radio wave (feeding signal) having a desired directivity is transmitted from the array antenna 110.

Next, the control unit 150 sets the control variable N to 1 (S11). Next, the control unit 150 instructs the control device 300 that controls the robot 400 to operate the robot 400 in the Nth operation pattern (S12). As a result, the robot 400 operates in the Nth operation pattern.

The power transmission device 100 receives radio waves from the environment via each antenna element 112 of the array antenna 110 (S13).

The control unit 150 calculates Doppler effect information based on the signal received by each antenna element 112 of the array antenna 110 (S14). Specifically, first, the receiving unit 140 removes the same frequency component as the transmission frequency fout from the signal received by each antenna element 112, and removes only the component varied depending on the environment (for example, the reflected wave from the robot 400). Generate a signal that contains. Then, the control unit 150 Fourier transforms the signal including the fluctuation component due to this environment to obtain a plurality of Doppler frequencies and their intensities (amplitudes). Then, the information of the Doppler frequency and its intensity (amplitude) is used as the Doppler effect information. The Doppler effect information is disclosed in, for example, Japanese Patent Application Laid-Open No. 2017-211348.

Calculation of Doppler effect information (S12 to S14) for each motion pattern is executed for all motion patterns of the robot 400 (S15, S17). When the above processing (S12 to S14) is executed for all the operation patterns, the control unit 150 is as shown in FIG. 5 based on the calculated Doppler effect information (information on the Doppler frequency and its intensity (amplitude)). The reference propagation environment data is generated and registered in the propagation environment table in the memory 160 (S16).

As described above, the reference propagation environment data regarding the Doppler effect can be obtained.

2.2 Power transmission with foreign matter detection operation Next, the power transmission operation with foreign matter detection operation of the wireless power transmission system 10 will be described. FIG. 8 is a flowchart showing a power transmission operation accompanied by an object detection operation in the power transmission device 100 of the wireless power transmission system 10. The process shown in FIG. 8 is periodically executed at predetermined time intervals.

The control unit 150 of the power transmission device 100 acquires an operation pattern number indicating an operation pattern of the operating robot 400 from the control device 300 that controls the robot 400 (S21). Based on the acquired operation pattern number, the control unit 150 refers to the propagation environment table stored in the memory 160 and acquires the reference propagation environment data corresponding to the current operation pattern of the robot (S22).

The control unit 150 measures the current propagation environment data based on the radio waves received by the array antenna 110 (S23). Specifically, when the power transmission device 100 is transmitting power, the receiving unit 140 removes the same frequency component as the transmission frequency fout from the signal received by each antenna element 112 of the array antenna 110, and fluctuates depending on the environment. Only the components (for example, the reflected wave from the robot 400) are extracted and transmitted to the control unit 150. On the other hand, when the power transmission device 100 does not transmit power, the power transmission device 100 transmits power for a very short period of time, and removes the same frequency component as the transmission frequency fout from the signal received by each antenna element 112 of the array antenna 110. Only the components that have changed depending on the environment are extracted and transmitted to the control unit 150. The control unit 150 calculates Doppler effect information (Doppler frequency and intensity) using the signal received from the reception unit 140, and obtains a measured value of propagation environment data.

The control unit 150 compares the reference propagation environment data stored in the memory 160 with the current propagation environment data obtained by the measurement (S24).

When both are in agreement (YES in S24), the control unit 150 starts the power supply when the power supply is not performed, and continues the power supply when the power supply has already been performed (S25). In this case, it can be determined that the radio wave propagation environment state has not changed from the reference state, and it is considered that no foreign matter such as a person has entered the detection range S, so that it is not necessary to stop the power supply. The match includes both the case where the reference propagation environment data and the current propagation environment data obtained by the measurement completely match, and the case where the difference between them is within a predetermined allowable range.

On the other hand, when the two do not match (NO in S24), the control unit 150 stops the power supply (S26). In this case, it is considered that a foreign substance such as a person has entered the detection range S, so it is necessary to stop the power supply. It should be noted that the power supply may be continued in a state where the magnitude of the transmitted power is reduced to a level that does not affect an object such as a person without stopping the power supply.

3. 3. Summary As described above, the wireless power transmission system 10 of the present embodiment wirelessly supplies electric power to the power receiving device 200 in an environment in which the power transmission device 100 and the robot 400 that can move in a plurality of operation patterns are arranged. The power transmission device 100 is information indicating a state of an array antenna 110 including a plurality of antenna elements 112 for transmitting radio waves for supplying power and a state of a radio wave propagation environment within the detection range S, and is within the detection range S. After obtaining the reference propagation environment data (an example of the first environment information) obtained in advance based on the signal received by the array antenna 110 in the state where no foreign matter is present (reference state) and the reference propagation environment data, the array antenna A control unit that detects the entry of foreign matter in the detection range S based on the propagation environment data (an example of the second environmental information) indicating the state of the radio wave propagation environment in the detection range S obtained based on the signal received in 110. 150 and. The reference propagation environment data is obtained for each operation pattern, and includes changes in the state of the radio wave propagation environment at regular intervals when the robot operates in each operation pattern. The control unit 150 obtains the propagation environment data (an example of the second environment information) based on the signal received by the array antenna 110, acquires the operation pattern of the robot 400 when the propagation environment data is obtained, and acquires the operation pattern. The reference propagation environment data including the change in the state of the propagation environment of the radio wave at regular intervals when the robot 400 is operated is acquired, and the detection is performed based on the comparison result between the obtained propagation environment data and the acquired reference propagation environment data. The presence or absence of foreign matter invading in the range S is detected.

As described above, in the wireless power transmission system 10 of the present embodiment, the difference between the propagation environment data obtained based on the signal received by the array antenna 110 at the time of detecting a foreign object and the reference propagation environment data measured in advance in the reference state is used. Based on this, the presence or absence of foreign matter entering in the detection range S is detected. As a result, even if there is a moving object such as a robot within the detection range S in a normal operating environment, foreign matter can be detected accurately based on the signal received by the array antenna 110 without erroneous detection.

Further, the present embodiment discloses a foreign matter detection method in the wireless power transmission system 10 used in an environment in which a robot 400 that can move in a plurality of operation patterns is arranged. The foreign matter detection method is information that transmits radio waves for supplying power via an array antenna 110 provided with a plurality of antenna elements, and the control unit 150 indicates the state of the radio wave propagation environment within the detection range S. Therefore, the reference propagation environment data is obtained in advance based on the signal received by the array antenna in a state where no foreign matter is present in the detection range. The reference propagation environment data is obtained for each operation pattern, and includes changes in the state of the radio wave propagation environment at regular intervals when the robot operates in each operation pattern. After obtaining the reference propagation environment data by the control unit 150, the propagation environment data indicating the state of the radio wave propagation environment in the detection range S is obtained based on the signal received by the array antenna 110, and the robot when the propagation environment data is obtained. The motion pattern of is acquired, and the reference propagation environment data including the change in the state of the radio wave propagation environment at regular intervals when the robot operates according to the acquired motion pattern is acquired. Further, the control unit 150 compares the obtained propagation environment data with the acquired reference propagation environment data, and detects the presence or absence of foreign matter in the detection range S based on the comparison result.

Further, the present embodiment discloses the concept of a foreign matter detecting device that detects the intrusion of foreign matter in the detection range S in an environment in which robots that move in a plurality of motion patterns are arranged. The foreign matter detection device is information indicating the state of the radio wave propagation environment in the detection range S and the array antenna 110 having a plurality of antenna elements that transmit radio waves in the detection range S, and there is no foreign matter in the detection range. In the state, the reference propagation environment data obtained in advance based on the signal received by the array antenna 110 and the radio wave propagation environment in the detection range S obtained based on the signal received by the array antenna 110 after obtaining the reference propagation environment data. A control unit 150 that detects the entry of foreign matter in the detection range S based on the propagation environment data indicating the state is provided. The reference propagation environment data is obtained for each operation pattern, and includes changes in the state of the radio wave propagation environment at regular intervals when the robot operates in each operation pattern. The control unit 150 obtains the propagation environment data based on the signal received by the array antenna 110, acquires the motion pattern of the robot when the propagation environment data is obtained, and at regular time intervals when the robot operates according to the acquired motion pattern. The reference propagation environment data including the change in the state of the propagation environment of the radio wave is acquired, and the presence or absence of foreign matter in the detection range S is detected based on the comparison result between the acquired reference propagation environment data and the obtained propagation environment data. ..

(Embodiment 2)
In the first embodiment, Doppler effect information is adopted as the radio wave propagation environment data. On the other hand, in the present embodiment, the propagation coefficient is adopted as the propagation environment data of the radio wave. Hereinafter, the wireless power transmission system of the present embodiment will be described.

FIG. 9 is a block diagram showing a configuration of a wireless power transmission system according to a second embodiment of the present invention. The wireless power transmission system 10b of the present embodiment is different from that of the first embodiment in that the power transmission device 100b further includes a transmission unit 170 that outputs a transmission request for a beacon signal to the power reception device 200b. The power receiving device 200b is different from that of the first embodiment in that the power receiving device 200b includes a beacon transmitting unit 240 that generates a beacon signal and transmits it via the antenna 210. The beacon signal is a very short RF signal containing unique information such as the serial number of the power receiving device 200b.

In the present embodiment, the power transmission device 100b detects a difference from the propagation environment of the reference state based on the state of the beacon signal received from the power reception device 200b, and detects the entry of foreign matter into the detection range S according to the detection result. do. That is, with respect to the beacon signal received from the power receiving device 200b in the reference state where there is no foreign matter, it is detected whether or not the beacon signal received from the power receiving device 200b fluctuates during the power transmission operation. Then, when the fluctuation is detected, it is detected that a foreign substance such as a person has entered the detection range S. The beacon signal transmitted from the power receiving device 200b is modulated by the entry of foreign matter into the detection range S by the time it is received by the array antenna 110. Therefore, the entry of foreign matter into the detection range S can also be detected by observing the beacon signal received by the array antenna 110.

FIG. 10 is a flowchart showing a measurement operation of reference propagation environment data in the wireless power transmission system 10b of the second embodiment. The process shown in FIG. 10 is performed in advance in the environment in which the wireless power transmission system 10b is installed, before the start of the normal power transmission operation. Further, it is assumed that the robot 400 is arranged within the detection range S in the environment where the wireless power transmission system 10b is installed.

First, the control unit 150 of the power transmission device 100b starts a power supply operation for the power reception device 200b (S40). Next, the power transmission device 100 requests the power reception device 200b to transmit a beacon signal (S41). Therefore, the control unit 150 instructs the transmission unit 170 to transmit the transmission request of the beacon signal. The transmission unit 170 transmits a transmission request for the beacon signal via the array antenna 110. When the power receiving device 200b receives the beacon signal transmission request from the power transmission device 100b, the beacon transmitting unit 240 starts transmitting the beacon signal.

The control unit 150 of the power transmission device 100b sets the control variable N to 1 (S42). The control unit 150 instructs the control device 300 that controls the robot 400 to operate the robot 400 in the Nth operation pattern (S43). As a result, the robot 400 operates in the Nth operation pattern.

The receiving unit 140 of the power transmitting device 100b receives the beacon signal from the power receiving device 200b via each antenna element 112 of the array antenna 110 (S44).

The control unit 150 calculates the propagation coefficient based on the beacon signal received by each antenna element 112 of the array antenna 110 (S45). The propagation coefficient is an element of the channel matrix H shown below.
y = Hx + w (1)
Here, y is the strength of the received signal received by each antenna element 112 of the array antenna 110, x is the strength of the transmitted signal, and w is the noise received by each antenna element of the array antenna (Japanese Patent Laid-Open No. 2008-086003). Etc.).

Specifically, first, the receiving unit 140 calculates the power Pi and the phase θi of the beacon signal from the beacon signal received by each antenna element (i) 112. The control unit 150 calculates the propagation coefficient (each element of H) based on the power Pi and the phase θi of the beacon signal.

The calculation processing of the propagation coefficient for each operation pattern (S43 to S45) is executed for all the operation patterns of the robot 400 (S46, S48). When the above processing (S43 to S45) is executed for all the operation patterns (YES in S46), the control unit 150 generates the reference propagation environment data as shown in FIG. 5 based on the calculated propagation coefficient. Register in the propagation environment table in the memory 160 (S47).

As described above, the reference propagation environment data regarding the propagation coefficient can be obtained.

Next, a power transmission operation accompanied by an object detection operation of the wireless power transmission system 10b will be described. FIG. 11 is a flowchart showing a power transmission operation accompanied by an object detection operation in the power transmission device 100b of the wireless power transmission system 10b. The process shown in FIG. 11 is periodically executed at predetermined time intervals.

First, the control unit 150 of the power transmission device 100b transmits a transmission request for the beacon signal to the power reception device 200b (S50). Upon receiving the request for transmitting the beacon signal, the power receiving device 200 starts transmitting the beacon signal.

The control unit 150 acquires an operation pattern number indicating the current operation pattern of the operating robot 400 from the control device 300 that controls the robot 400 (S51). Based on the acquired operation pattern number, the control unit 150 refers to the propagation environment table stored in the memory 160 and acquires the reference propagation environment data corresponding to the current operation pattern of the robot (S52).

The control unit 150 measures the current propagation environment data based on the beacon signal received by the array antenna 110 (S53). Specifically, the control unit 150 calculates the propagation coefficient based on the power Pi and the phase θi of the beacon signal.

The control unit 150 compares the reference propagation environment data stored in the memory 160 with the current propagation environment data obtained by the measurement (S54).

When both are in agreement (YES in S54), the control unit 150 starts the power supply when the power supply is not currently performed, and continues the power supply when the power supply has already been performed (S55). In this case, it can be determined that the radio wave propagation environment state has not changed from the reference state, and it is considered that no foreign matter such as a person has entered the detection range S, so that it is not necessary to stop the power supply. The match includes both the case where the reference propagation environment data and the current propagation environment data obtained by the measurement completely match, and the case where the difference between them is within a predetermined allowable range.

On the other hand, when the two do not match (NO in S54), the control unit 150 stops the power supply (S56). In this case, it is considered that a foreign substance such as a person has entered the detection range S, so it is necessary to stop the power supply. It should be noted that the power supply may be continued after reducing the magnitude of the transmitted power to a level that does not affect people, mobile machines, or the like without stopping the power supply.

As described above, the radio wave propagation coefficient in the power transmission environment may be used as an index indicating the radio wave propagation environment.

(Other embodiments)
In the above embodiment, an example in which the object detection device of the present disclosure is applied to a wireless power transmission system has been described, but the object detection device of the present disclosure may be applied to another device or system. That is, the object detection device of the present disclosure can be applied to any device or system capable of transmitting a predetermined signal via an array antenna and receiving a signal by the array antenna.

In the above embodiment, the Doppler effect information and the propagation coefficient are adopted as the radio wave propagation environment data, but other types of information may be adopted. That is, any information can be adopted as long as it is information indicating the propagation characteristics of radio waves in the space of the range for detecting foreign matter (for example, the detection range S).

In the above embodiment, the reference propagation environment data is stored in the memory 160 built in the power transmission devices 100 and 100b, but the reference propagation environment data is stored in an external device or recording medium of the power transmission devices 100 and 100b. You may. The power transmission devices 100 and 100b may acquire reference propagation environment data from an external device. For example, the power transmission devices 100 and 100b may acquire the reference propagation environment data from an external server via the network.

Since the above-described embodiment is for exemplifying the technique in the present disclosure, various changes, replacements, additions, omissions, etc. can be made within the scope of claims or the equivalent thereof.

10, 10b Wireless power transmission system 100, 100b Transmission device 110 Array antenna 112 Antenna element 120 Directional control unit 130 Power supply signal generation unit 140 Reception unit 150 Control unit 160 Memory 170 Transmission unit 200, 200b Power receiving device (for example, sensor)
210 Antenna 300 Control device 400 Robot 420 Person P Power supply range S Detection range

Claims (10)

A power transmission device that wirelessly supplies power to a power receiving device in an environment in which robots that move in multiple motion patterns are arranged.
An array antenna equipped with multiple antenna elements that transmit radio waves to supply power,
Information indicating the state of the propagation environment of radio waves within a predetermined detection range, the first environmental information obtained in advance based on the signal received by the array antenna in a state where no foreign matter exists within the detection range, and After obtaining the first environmental information, the foreign matter in the detection range is based on the second environmental information indicating the state of the radio wave propagation environment in the detection range obtained based on the signal received by the array antenna. Equipped with a control unit that detects intrusion,
The first environmental information is obtained for each operation pattern, includes a change in the state of the radio wave propagation environment at regular time intervals when the robot operates in each operation pattern, and the control unit uses the array antenna. The second environmental information is obtained based on the signal received in, the operation pattern of the robot when the second environmental information is obtained is acquired, and a certain period of time when the robot operates with the acquired operation pattern. The first environmental information including the change in the state of the propagation environment of each radio wave is acquired, and the entry of foreign matter in the detection range is based on the comparison result between the acquired first environmental information and the second environmental information. Detects the presence or absence of
Power transmission device. The power transmission device according to claim 1, wherein the first and second environmental information includes information indicating the Doppler effect of radio waves received by the array antenna. The power transmission device according to claim 1, wherein the first and second environmental information includes information indicating a propagation coefficient of radio waves received by the array antenna. It further includes a receiving unit that receives a beacon signal from the power receiving device.
The control unit generates the first and second environmental information from the received beacon signal.
The power transmission device according to claim 3. A storage unit that stores the first environmental information in advance is further provided.
The control unit acquires the first environmental information from the storage unit.
The power transmission device according to claim 1. The control unit acquires the first environmental information from the outside of the power transmission device.
The power transmission device according to claim 1. The power transmission device according to claim 1, wherein the control unit stops power transmission to the power receiving device or reduces the power transmitted to the power receiving device when it detects the intrusion of foreign matter in the detection range. The power transmission device according to any one of claims 1 to 7.
A power receiving device that receives power wirelessly from the power transmitting device, and
Wireless power transmission system with. A foreign matter detection method in a wireless power transmission system used in an environment where robots that move in multiple motion patterns are arranged.
Information for transmitting radio waves for supplying power via an array antenna provided with a plurality of antenna elements and indicating the state of the radio wave propagation environment within the detection range by the control unit, which is foreign matter within the detection range. First environmental information is obtained in advance based on the signal received by the array antenna in the absence of
The first environmental information is obtained for each of the operation patterns, and includes a change in the state of the radio wave propagation environment at regular intervals when the robot operates in each operation pattern.
After obtaining the first environmental information by the control unit, the second environmental information indicating the state of the radio wave propagation environment in the detection range is obtained based on the signal received by the array antenna, and the control unit obtains the second environmental information. The operation pattern of the robot when the second environmental information is obtained is acquired, and the operation pattern is acquired.
The control unit acquires the first environmental information including the change in the state of the radio wave propagation environment at regular time intervals when the robot operates in the acquired operation pattern.
The control unit compares the acquired first environmental information with the second environmental information, and detects the presence or absence of foreign matter in the detection range based on the comparison result.
Foreign matter detection method. A foreign matter detection device that detects the entry of foreign matter within a predetermined detection range in an environment in which robots that move in a plurality of motion patterns are arranged.
An array antenna equipped with a plurality of antenna elements that transmit radio waves within the detection range, and
Information indicating the state of the radio wave propagation environment in the detection range, the first environmental information obtained in advance based on the signal received by the array antenna in a state where no foreign matter exists in the detection range, and the first environment information. After obtaining the environmental information of 1, the entry of foreign matter in the detection range is performed based on the second environmental information indicating the state of the propagation environment of the radio wave in the detection range obtained based on the signal received by the array antenna. Equipped with a control unit to detect
The first environmental information is obtained for each of the operation patterns, and includes a change in the state of the radio wave propagation environment at regular intervals when the robot operates in each operation pattern.
The control unit obtains the second environmental information based on the signal received by the array antenna, acquires the operation pattern of the robot when the second environmental information is obtained, and uses the acquired operation pattern to obtain the operation pattern. The first environmental information including the change in the state of the radio wave propagation environment at regular intervals when the robot operates is acquired, and the result of comparison between the acquired first environmental information and the second environmental information is obtained. Based on this, the presence or absence of foreign matter entering in the detection range is detected.
Foreign matter detection device.

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