Communication system, stationary body, and mobile body

Abstract

The position of a drone (2) with respect to a reference position associated with a take-off and landing port (3) is specified on the basis of communication that complies with UWB wireless communication standard and that occurs between a plurality of drone-side communication devices mounted on the drone (2) and a plurality of port-side communication devices mounted on the take-off and landing port (3). A detection region (A) is defined in association with at least one of the drone (2) and the reference position. Detection of an object positioned in the detection region (A) is performed, with radio waves used for said communication, at least temporarily by at least one the plurality of port-side communication devices and the plurality of drone-side communication devices.

Description

Communication system, stationary object, and mobile object

[0001] The present disclosure relates to a stationary object associated with a reference position and a mobile object that wirelessly communicates with the stationary object. The present disclosure also relates to a communication system including the stationary object and the mobile object.

[0002] Japanese Patent Application Laid-Open No. 2024-139777 discloses a system that controls a drone, which is an example of a mobile object, to reach a target position based on image information acquired by a camera mounted on the drone.

[0003] There is a need to be able to acquire the surrounding information of a mobile object without relying on image information.

[0004] One exemplary aspect that can be provided by the present disclosure is a communication system including: a plurality of first communication devices mounted on a mobile object; a plurality of second communication devices mounted on a stationary object; and a control device that specifies the position of the mobile object with respect to a reference position associated with the stationary object based on communication conforming to the UWB (Ultra-Wide Band) wireless communication standard performed between the plurality of first communication devices and the plurality of second communication devices. The control device causes at least one of the plurality of first communication devices and the plurality of second communication devices to at least temporarily detect an object located within a region defined in association with at least one of the mobile object and the reference position by using radio waves used for the communication.

[0005] One exemplary aspect that can be provided by the present disclosure is a stationary object associated with a reference position, including: a plurality of communication devices; and a control device that specifies the position of the mobile object with respect to the reference position based on communication conforming to the UWB wireless communication standard performed between the plurality of communication devices and a plurality of communication devices mounted on the mobile object. The control device causes at least one of the plurality of communication devices to at least temporarily detect an object located within a region defined in association with at least one of the mobile object and the reference position by using radio waves used for the communication.

[0006] One embodiment that may be provided by this disclosure is a mobile body comprising: a plurality of communication devices; and a control device that determines the position of the stationary body relative to a reference position associated with the stationary body based on communication in accordance with the UWB wireless communication standard between the plurality of communication devices and a plurality of communication devices mounted on a stationary body, wherein the control device causes at least one of the plurality of communication devices to at least temporarily detect an object located within a region defined in association with at least one of the mobile body and the reference position using radio waves used in the communication.

[0007] According to the configurations described in each of the above examples, based on communication compliant with a UWB wireless communication standard that enables not only positioning but also radar functions, it is possible to detect not only the position of a moving object relative to a reference position but also objects located within a defined area associated with at least one of the moving object and the reference position. Therefore, it is possible to acquire information about the surroundings of a moving object without relying on image information.

[0008] This shows an example of a drone and landing / takeoff port included in a communication system according to one embodiment. The functional configuration of the drone and landing / takeoff port in Figure 1 is illustrated. An example of the communication flow between the first port-side communicator and the first drone-side communicator in Figure 2 is shown. Another example of the communication flow between the first port-side communicator and the first drone-side communicator in Figure 2 is shown. An example of object detection processing performed by the drone in Figure 1 is shown. Another example of object detection processing performed by the drone in Figure 1 is shown. Another example of object detection processing performed by the drone in Figure 1 is shown. An example of a detection area is illustrated. Another example of a detection area is illustrated. An example of the processing flow performed by the drone in Figure 1 is illustrated.

[0009] The embodiments will be described in detail below with reference to the attached drawings. In the drawings used in the following description, the scale has been appropriately changed to make each element recognizable.

[0010] Figure 1 illustrates the external appearance of a drone 2 and a landing / takeoff port 3 included in a communication system 1 according to one embodiment. The communication system 1 is configured to land the drone 2 at a target position at the landing / takeoff port 3 using communication compliant with the UWB wireless communication standard. The drone 2 is an example of an aerial body and an example of a mobile body. The landing / takeoff port 3 is an example of a stationary body.

[0011] An example of a UWB wireless communication standard is channel number 9 in IEEE 802.15.4z (center frequency: 7987.2 MHz, frequency bandwidth: 499.2 MHz).

[0012] As illustrated in Figure 2, the drone 2 is equipped with multiple drone-side communication devices. In this example, the drone 2 is equipped with a first drone-side communication device D1, a second drone-side communication device D2, a third drone-side communication device D3, and a fourth drone-side communication device D4. Multiple drone-side communication devices are an example of multiple first communication devices.

[0013] On the other hand, the arrival / departure port 3 is equipped with multiple port-side communicators. In this example, the arrival / departure port 3 is equipped with a first port-side communicator P1, a second port-side communicator P2, a third port-side communicator P3, and a fourth port-side communicator P4. Multiple port-side communicators are an example of multiple second communicators.

[0014] Each of the multiple drone-side communicators and multiple port-side communicators has a well-known configuration that enables bidirectional communication in accordance with the aforementioned UWB wireless communication standard. In other words, each of the multiple drone-side communicators and multiple port-side communicators has radio wave transmission and reception functions.

[0015] Drone 2 is equipped with a drone-side control device 21. The drone-side control device 21 is configured to control the radio wave transmission operation of each of the multiple drone-side communication devices. The drone-side control device 21 is configured to acquire information superimposed on the radio waves received by each of the multiple drone-side communication devices.

[0016] The arrival / departure port 3 is equipped with a port-side control device 31. The port-side control device 31 is configured to control the radio wave transmission operation of each of the multiple port-side communication devices. The port-side control device 31 is configured to acquire information superimposed on the radio waves received by each of the multiple port-side communication devices.

[0017] Referring to Figure 3, the positioning process performed between the first port-side communication device P1 and the first drone-side communication device D1 will be explained.

[0018] The port-side control device 31 causes the first port-side communicator P1 to transmit a first start signal p1 at time t1. The first start signal p1 is received by the first drone-side communicator D1 at time t2.

[0019] The drone-side control device 21, in response to the first start signal p1, causes the first drone-side communicator D1 to transmit a first response signal r1 at time t3. The first response signal r1 is received by the first port-side communicator P1 at time t4.

[0020] The port-side control device 31, in response to the first response signal r1, causes the first port-side communicator P1 to transmit a first completion signal f1 at time t5. The first completion signal f1 is configured to include information that identifies times t1, t4, and t5. The first completion signal f1 is received by the first drone-side communicator D1 at time t6.

[0021] The drone-side control device 21 holds information that identifies time points t2, t3, and t6. Adding the information that identifies time points t1, t4, and t5 provided by the first completion signal f1, the drone-side control device 21 calculates the following equation to obtain the distance d11 between the first port-side communicator P1 and the first drone-side communicator D1. The symbol c is the speed of light. d11 = c[(t4 - t1) - (t3 - t2) + (t6 - t3) - (t5 - t4)] / 4

[0022] Similarly, the drone-side control device 21 obtains the distance d21 between the second port-side communicator P2 and the first drone-side communicator D1, the distance d31 between the third port-side communicator P3 and the first drone-side communicator D1, and the distance d41 between the fourth port-side communicator P4 and the first drone-side communicator D1. Based on the distances between the first drone-side communicator D1 and each of the four port-side communicators, the three-dimensional coordinates of the first drone-side communicator D1 can be determined by solving a system of three equations well known in positioning technology.

[0023] The drone-side control device 21 controls the flight of the drone 2 so that the three-dimensional coordinates of the identified first drone-side communication device D1 are brought closer to the three-dimensional coordinates corresponding to the target position of the landing port 3. This allows the drone 2 to land at the landing port 3.

[0024] In this embodiment, the distance between each of the four port-side communication devices is obtained in the same manner for each of the second drone-side communication device D2, the third drone-side communication device D3, and the fourth drone-side communication device D4. Therefore, the three-dimensional coordinates of the four drone-side communication devices are obtained based on a total of 16 pieces of distance information.

[0025] In the example above, the start signal is transmitted from multiple port-side communicators mounted on the arrival / departure port 3. However, as illustrated in Figure 4, the start signal may also be transmitted from multiple drone-side communicators mounted on the drone 2.

[0026] In this case, the acquired distance information is located at the take-off / arrival port, so in order for drone 2 to determine its own position, the acquired distance information is transmitted from take-off / arrival port 3 to drone 2. For example, the transmission of distance information is performed using communication compliant with the UWB wireless communication standard.

[0027] However, communication compliant with the UWB wireless communication standard has the characteristic that the power consumption burden is greater on the receiving side than on the transmitting side. As an alternative to avoid this problem, distance information can be transmitted using signals that do not comply with the UWB wireless communication standard.

[0028] Specifically, as illustrated in Figure 2, the drone 2 and the landing / takeoff port 3 may be equipped with auxiliary communication devices 22 and 32, respectively. The auxiliary communication devices 22 and 32 are configured to send and receive auxiliary signals ax using short-range wireless communication that does not conform to the UWB wireless communication standard. Examples of such short-range wireless communication include Bluetooth®, Bluetooth Low Energy®, ZigBee®, and Wi-Fi®.

[0029] Each of the multiple drone-side communication devices and the multiple port-side communication devices may have a function (so-called radar function) that detects the presence or absence of an object in a specific direction by transmitting radio waves (detection waves) compliant with the UWB wireless communication standard in a specific direction and receiving reflected waves from that direction.

[0030] Figure 1 illustrates a state in which a drone-side detection wave DS is emitted from the drone 2 toward a detection area A defined in association with the target position of the landing / takeoff port 3. For example, when a person 4 enters the detection area A, the drone-side reflected wave DR, which is generated by the reflection of the drone-side detection wave DS by the person 4, is received by the drone 2.

[0031] Based on the time elapsed between the emission of the drone-side detection wave DS and the reception of the drone-side reflected wave DR, the distance to the object that generated the drone-side reflected wave DR can be determined. Since the drone 2 can determine its own position through the positioning process described above, it can determine whether the object is located within the detection area A based on the distance to the object determined based on the drone-side reflected wave DR.

[0032] Similarly, the diagram illustrates a state in which a port-side detection wave PS is emitted from the arrival / departure port 3 toward the detection area A. For example, when a person 4 enters the detection area A, the port-side detection wave PS is reflected by person 4, and the resulting port-side reflected wave PR is received by the arrival / departure port 3.

[0033] Based on the time elapsed between the emission of the port-side detection wave PS and the reception of the port-side reflected wave PR, the distance to the object that generated the port-side reflected wave PR can be determined. Since the position of the stationary departure / arrival port 3 is known, it can be determined whether the object is located within the detection area A based on the distance to the object identified based on the port-side reflected wave PR.

[0034] In the communication system 1 according to this embodiment, the detection process of an object located within the detection area A using radio waves compliant with the UWB wireless communication standard is performed at least temporarily by at least one of the multiple drone-side communication devices and the multiple port communication devices.

[0035] Figure 5 shows an example of object detection processing performed by the drone-side control device 21. In this example, the positioning processing over a period T1, as described with reference to Figures 3 and 4, and the object detection processing over a period T2, as described with reference to Figure 1, are periodically repeated. Both the positioning processing and the object detection processing are performed using all of the first drone-side communicators D1, D2, D3, and D4. In other words, the drone-side control device 21 temporarily causes all of the multiple drone-side communicators to perform object detection processing.

[0036] Figure 6 shows another example of object detection processing performed by the drone-side control device 21. In this example, positioning processing is always performed by the first drone-side communicator D1, the second drone-side communicator D2, and the third drone-side communicator D3, and object detection processing is always performed by the fourth drone-side communicator D4. In other words, the drone-side control device 21 causes one of the multiple drone-side communicators to always perform object detection processing.

[0037] Figure 7 shows another example of object detection processing performed by the drone-side control device 21. In this example, each of the multiple drone-side communication devices periodically repeats positioning processing over period T1 and object detection processing over period T2. On the other hand, at any given time, only one drone-side communication device performs object detection processing. That is, a single drone-side communication device performing object detection processing is sequentially switched so that the periods T2 do not overlap. In other words, the drone-side control device 21 temporarily causes one of the multiple drone-side communication devices to perform object detection processing.

[0038] Figure 8 shows another example of object detection processing performed by the drone-side control device 21. In this example, positioning processing is always performed by the first drone-side communicator D1 and the third drone-side communicator D3, and object detection processing is always performed by the second drone-side communicator D2 and the fourth drone-side communicator D4. In other words, the number of drone-side communicators that always perform object detection processing can be appropriately determined as long as positioning processing can be performed in parallel. This explanation can also be applied to the processing example in Figure 7.

[0039] Although not shown in the diagram, the port-side control device 31 can also cause the first port-side communication device P1, the second port-side communication device P2, the third port-side communication device P3, and the fourth port-side communication device P4 to perform the processing examples described with reference to Figures 5 to 8.

[0040] Object detection processing at a specific point in time may be performed by either the drone-side control device 21 or the port-side control device 31, or by both.

[0041] According to the configuration of this embodiment, based on communication compliant with the UWB wireless communication standard, which enables not only positioning but also radar functionality, it is possible to detect not only the position of the drone 2 relative to the target position but also objects located within the detection area A. Therefore, it is possible to acquire information about the surroundings of the drone 2 without relying on image information.

[0042] As illustrated in FIG. 1, when approaching the target position of the landing / takeoff port 3 of the drone 2, it is preferable that a detection area A is defined between the drone 2 and the target position. With such a configuration, it is possible to detect the presence of an object that may interfere with the landing or unloading of the drone 2 at the landing / takeoff port 3.

[0043] The position of the detection area A may be constant or may be changed according to the situation. When the drone 2 takes off from the landing / takeoff port 3, as illustrated in FIG. 9, it is preferable that the detection area A is defined so as to include the planned flight path of the drone 2. With such a configuration, it is possible to detect the presence of an object that may interfere with the takeoff of the drone 2 from the landing / takeoff port 3.

[0044] As illustrated in FIG. 10, the drone-side detection area AD assigned to a plurality of drone-side communication devices and the port-side detection area AP assigned to a plurality of port-side communication devices may be different. In this example, the drone-side detection area AD is defined within a predetermined distance range from a reference position determined for the drone 2. That is, the drone-side detection area AD can move together with the drone 2. On the other hand, the port-side detection area AP is defined within a predetermined distance range from the target position of the landing / takeoff port 3. The port-side detection area AP in this example is stationary.

[0045] With such a configuration, through the cooperation of the drone-side control device 21 and the port-side control device 31, it is possible to set a more dynamic and highly flexible detection area. Note that the object detection process by the drone-side control device 21 and the object detection process by the port-side control device 31 do not necessarily have to be performed simultaneously.

[0046] FIG. 11 illustrates the flow of a process that can be executed by the drone-side control device 21 mounted on the drone 2.

[0047] First, it is determined whether an object exists within the detection area A through the above-described object detection process (STEP 1). The process is repeated until it is determined that an object exists (NO in STEP 1).

[0048] When it is determined that an object exists within the detection area A (YES in STEP 1), the movement schedule of the drone 2 is changed (STEP 2). The change is made to abort the entry into the detection area A. As an example, the drone-side control device 21 controls the rotation speed of each of the plurality of propellers mounted on the drone 2 so as to maintain the current position. As another example, the drone-side control device 21 controls the rotation speed of each propeller so as to achieve a movement that avoids the detection area A or a movement that causes the object to exit the detection area A.

[0049] It is preferable that at least one of the fact that an object has been detected within the detection area A and the fact that the movement schedule of the drone 2 has been changed is notified to the movement schedule manager of the drone 2 through appropriate means.

[0050] According to such a configuration, it is possible to suppress the occurrence of a situation in which the takeoff / landing or unloading of the drone 2 is hindered by an object existing within the detection area A.

[0051] Subsequently, the object detection process is executed, and it is determined whether an object is absent within the detection area A (STEP 3). This process is repeated until it is determined that the object is absent (NO in STEP 3).

[0052] When it is determined that an object is absent within the detection area A (YES in STEP 3), the drone-side control device 21 controls the rotation speed of each propeller so as to achieve a movement that causes the drone 2 to reach the target position. (STEP 4). In other words, based on the determination that the cause that may hinder the takeoff / landing or unloading of the drone 2 has been eliminated, the movement toward the target position is resumed. At that time, the necessity of re-entering the detection area A is not questioned.

[0053] At least one of the drone-side control device 21 and the port-side control device 31 having the various functions described so far is realized by at least one dedicated integrated circuit provided with a storage element in which a computer program for realizing the function is pre-installed. Examples of the dedicated integrated circuit include a microcontroller, an ASIC, an FPGA, and the like.

[0054] Alternatively, at least one of the drone-side control device 21 and the port-side control device 31 may be implemented by at least one general-purpose microprocessor operating in cooperation with at least one general-purpose memory. Examples of general-purpose microprocessors include CPUs, MPUs, and GPUs. Examples of general-purpose memory include ROMs and RAMs. In this case, the ROM may store a computer program for implementing the function. The general-purpose microprocessor selects at least a portion of the program stored in the ROM and loads it onto the RAM, and then executes the above-described process in cooperation with the RAM.

[0055] At least one of the drone-side control device 21 and the port-side control device 31 may be implemented by a combination of a general-purpose microprocessor and a dedicated integrated circuit.

[0056] The configurations described herein are merely examples to facilitate understanding of this disclosure. Each configuration example may be modified and combined with other configuration examples as appropriate, without departing from the spirit of this disclosure.

[0057] The "UWB wireless communication standard" used in the above embodiment example originates from a standardization standard compliant with IEEE 802.15. However, this expression is not intended to limit the scope to that standard. Any short-range wireless communication standard that can determine the relative positions of communication devices with high accuracy and has advantages such as low power consumption and low interference with other communications may be adopted. For example, distance values ​​may be obtained by short-range wireless communication compliant with the Bluetooth Low Energy (registered trademark) standard.

[0058] In the above embodiment, the communication system 1 is used to determine the position of the drone 2 relative to the target position. However, the communication system 1 may also be used to determine the position of an aircraft capable of carrying a person. Alternatively, the communication system 1 may be used to determine the position of a mobile body other than the drone 2. Examples of such mobile bodies include vehicles, trains, and ships. Such mobile bodies do not necessarily require a driver.

[0059] In part with respect to this disclosure, the contents of Japanese Patent Application No. 2025-005338, filed on January 15, 2025, are incorporated herein by reference.

Claims

1. A communication system comprising: a plurality of first communication devices mounted on a moving body; a plurality of second communication devices mounted on a stationary body; and a control device that determines the position of the moving body relative to a reference position associated with the stationary body based on communication between the plurality of first communication devices and the plurality of second communication devices in accordance with the UWB wireless communication standard, wherein the control device causes at least one of the plurality of first communication devices and the plurality of second communication devices to at least temporarily detect an object located within a defined area associated with at least one of the moving body and the reference position using radio waves used for the communication.

2. The communication system according to claim 1, wherein the area is defined between the moving body and the reference position when the moving body approaches the reference position.

3. The communication system according to claim 1 or 2, wherein the region is defined to include the planned path of the moving body before the moving body moves away from the reference position.

4. The communication system according to any one of claims 1 to 3, wherein the area assigned to the plurality of first communication devices and the area assigned to the plurality of second communication devices are different.

5. The communication system according to any one of claims 1 to 4, wherein the control device changes the movement schedule of the moving body when an object is detected within the area.

6. The communication system according to any one of claims 1 to 5, wherein the moving body is an aerial vehicle.

7. A stationary body associated with a reference position, comprising: a plurality of communication devices; and a control device that determines the position of the mobile body relative to the reference position based on communication in accordance with the UWB wireless communication standard between the plurality of communication devices and a plurality of communication devices mounted on a mobile body, wherein the control device causes at least one of the plurality of communication devices to at least temporarily detect an object located within a defined area associated with at least one of the mobile body and the reference position using radio waves used for the communication.

8. A mobile body comprising: a plurality of communication devices; and a control device that determines the position of the immobile body relative to a reference position based on communication in accordance with the UWB wireless communication standard between the plurality of communication devices and a plurality of communication devices mounted on a mobile body, wherein the control device causes at least one of the plurality of communication devices to at least temporarily detect an object located within a defined area associated with at least one of the mobile body and the reference position using radio waves used for the communication.

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