JP7458310B2 - Navigation device, mobile object, navigation method and computer program - Google Patents

Description

The present invention relates to a navigation device, a mobile object, a navigation method, and a computer program.

In recent years, navigation technology that assumes autonomously moving robots and self-driving vehicles traveling outdoors has been studied. For example, Patent Document 1 describes a navigation data generation system that acquires navigation data based on a navigation route and the node type of an intermediate node (an operation to be performed by a vehicle at a node) when automatically transporting an object. ing.

Special table 2019-537730 publication

When remotely monitoring a robot or self-driving vehicle that autonomously moves outdoors via wireless communication, it is preferable that the robot or self-driving vehicle move along a route that does not disconnect wireless communication. However, with the above-mentioned conventional navigation technology, it is not possible to perform a route search in a manner that avoids disconnection of wireless communication. Furthermore, it is preferable to be able to take appropriate measures if wireless communication is interrupted.

The present invention has been made in consideration of these circumstances, and its purpose is to realize stable wireless communication when remotely monitoring a mobile object by wireless communication, and also to realize stable wireless communication when wireless communication is disconnected. The aim is to take appropriate measures when such matters occur.

(1) One aspect of the present invention is a navigation device that provides route information indicating a route from a departure point to a destination to a moving object whose remote monitoring is performed via a wireless communication line, A location wireless quality information storage section that stores location wireless quality information recorded in association with the wireless communication quality at the location; and a location wireless quality information storage section that stores the location wireless quality information stored in the location wireless quality information storage section. a route search unit that searches for the route from among the candidates; and a wireless disconnection behavior determination unit that determines the action that the mobile body will take when wireless communication is disconnected while the mobile body is moving along the route. a transmission unit that transmits in advance radio disconnection behavior information indicating the behavior of the mobile body determined by the wireless disconnection behavior determining unit to the mobile body; and a transmitting unit that evaluates a risk in the case where wireless communication is disconnected for each location. a risk evaluation unit, the wireless disconnection action determination unit determines an action to be taken by the mobile body based on the risk evaluation result of the risk evaluation unit, and the risk evaluation unit determines the action to be taken by the mobile object when wireless communication is disconnected. This navigation device evaluates an estimated wireless disconnection continuation distance, which is an estimated value of the distance over which wireless communication continues to be disconnected .
(2) One aspect of the present invention is the navigation device according to (1) above, wherein the risk evaluation unit further evaluates the difficulty level when the mobile object autonomously moves through the estimated wireless disconnection continuation distance .
(3) In one aspect of the present invention, when the risk evaluation result exceeds a predetermined threshold, the wireless disconnection behavior determining unit determines the behavior of the moving body to return to a point where it can resume movement; On the other hand, if the risk evaluation result does not exceed the threshold, the navigation device according to any one of (1) or (2) above determines to continue moving along the route even after wireless communication is disconnected. be.
( 4 ) One aspect of the present invention is that the location wireless quality information storage unit stores location information in which base station identification information identifying a base station that provides wireless communication connection at each location is recorded in association with the location wireless quality information. The navigation device according to any one of (1) to (3) above, wherein wireless quality base station information is stored, and the risk evaluation unit determines the estimated wireless disconnection continuation distance based on the location wireless quality base station information. be.
( 5 ) One aspect of the present invention is the navigation according to any one of (1) to ( 4 ) above, wherein the mobile body is a mobile body that performs delivery, and the route is a route that the mobile body delivers. It is a device.

( 6 ) One aspect of the present invention is a mobile object that moves based on route information provided from the navigation device according to any one of (1) to ( 5 ) above, and that performs wireless communication with the navigation device. an information storage unit that stores the behavior information at the time of wireless disconnection received in advance from the navigation device; This is a moving body that includes a control unit that takes action.
( 7 ) One aspect of the present invention further includes a wireless disconnection cause determination unit that determines the cause of disconnection of wireless communication in the wireless communication unit, and the control unit is configured to determine the cause of the disconnection by the determination unit. The mobile object according to ( 6 ) above takes the action indicated by the radio disconnection action information based on the wireless disconnection action information.

( 8 ) One aspect of the present invention is a navigation method that provides route information indicating a route from a departure point to a destination to a moving object whose remote monitoring is performed via a wireless communication line, a step of storing location radio quality information recorded in association with radio communication quality at the location in a location radio quality information storage unit; and a location radio quality information stored in the location radio quality information storage unit; a route searching step of searching for the route from among the route candidates based on the information; and determining an action to be taken by the mobile body when wireless communication is disconnected while the mobile body is moving along the route. a step of determining behavior at the time of wireless disconnection, a step of transmitting in advance behavior information at the time of wireless disconnection indicating the behavior of the mobile object determined in the step of determining behavior at the time of wireless disconnection to the mobile object, and a step of disconnecting wireless communication for each location. a risk evaluation step of evaluating the risk in the case where the wireless disconnection occurs, and the step of determining the action at the time of wireless disconnection determines the action to be taken by the mobile body based on the risk evaluation result of the risk evaluation step, is a navigation method that evaluates an estimated wireless disconnection continuation distance, which is an estimated value of the distance over which wireless communication will continue to be disconnected when wireless communication is disconnected .

( 9 ) One aspect of the present invention provides a computer of a navigation device that provides route information indicating a route from a departure point to a destination for a mobile object whose remote monitoring is performed via a wireless communication line. a location wireless quality information storage step of storing location wireless quality information recorded in association with wireless communication quality at the location in a location wireless quality information storage unit; a route searching step of searching for the route from among the route candidates based on quality information; and determining an action that the mobile body takes when wireless communication is disconnected while the mobile body is moving along the route. a step of determining behavior at the time of wireless disconnection, a transmitting step of transmitting behavior information at the time of wireless disconnection indicating the behavior of the mobile object determined in the step of determining behavior at the time of wireless disconnection to the mobile body in advance, and a step of transmitting wireless communication for each location. a risk evaluation step of evaluating a risk in the case of disconnection, and the step of determining an action upon wireless disconnection determines an action that the moving object will take based on the risk evaluation result of the risk evaluation step. The risk evaluation step is a computer program that evaluates an estimated wireless disconnection continuation distance, which is an estimated value of the distance over which wireless communication will continue to be disconnected if wireless communication is disconnected .

According to the present invention, it is possible to achieve stable wireless communication when remotely monitoring a mobile object using wireless communication, and also to take appropriate measures if wireless communication is interrupted. is obtained.

FIG. 1 is a block diagram illustrating a configuration example of a navigation system according to an embodiment. 2 is a flowchart illustrating an example of an action procedure of a mobile robot when wireless communication is disconnected according to an embodiment. FIG. 2 is a diagram illustrating a configuration example of a location/wireless quality/base station ID storage unit according to an embodiment. 3 is a flowchart illustrating an example of a procedure of a route search method according to an embodiment. It is an explanatory diagram for explaining an example of the route search method concerning one embodiment. It is an explanatory diagram for explaining a route search method concerning one embodiment.

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, a navigation system in a delivery service system that performs delivery using autonomously moving robots (hereinafter referred to as mobile robots) will be described as an example.

FIG. 1 is a block diagram illustrating a configuration example of a navigation system 10 according to an embodiment. In FIG. 1, a mobile robot 2 communicates with a navigation device 4 via a wireless communication line. The mobile robot 2 is an example of a mobile object. The navigation device 4 provides the mobile robot 2 with route information indicating a route from a starting point to a destination.

The navigation device 4 according to this embodiment has a remote monitoring function in addition to the navigation function. Note that a device other than the navigation device 4 outside the mobile robot 2 may be provided with the remote monitoring function.

The navigation device 4 uses a remote monitoring function to remotely monitor the mobile robot 2 via wireless communication. For example, the navigation device 4 receives images captured by the mobile robot 2 and sounds captured by the mobile robot 2 via a wireless communication line, and displays or reproduces the received images and sounds. By viewing the image and the sound, the observer can monitor the movement status of the mobile robot 2 in real time. Therefore, in the delivery service system according to this embodiment, stable wireless communication in the mobile robot 2 is required. Therefore, in this embodiment, the navigation device 4 provides route information for realizing stable wireless communication in the mobile robot 2.

Furthermore, if wireless communication in the mobile robot 2 becomes unstable and communication with the navigation device 4 is interrupted, the mobile robot 2 will not be able to be controlled remotely. Therefore, in this embodiment, when the wireless communication in the mobile robot 2 is cut off, the mobile robot 2 is designed to take appropriate measures.

The configuration of a navigation system 10 according to this embodiment will be described below with reference to FIG.

[User terminal]
The user terminal 1 is a terminal used by a user of the delivery service system according to this embodiment (hereinafter referred to as a delivery service user). A delivery service user specifies the destination to which the package is to be delivered and requests delivery. The user terminal 1 may be a mobile communication terminal device such as a smartphone or a tablet computer (tablet PC), or may be a stationary communication terminal device (for example, a stationary personal computer). good.

The user terminal 1 includes a product ordering section 101 and a destination information input section 102. The product ordering unit 101 selects a product and orders the selected product in response to an operation by a delivery service user.

The product ordering unit 101 manages the remaining amount of items owned by the delivery service user in real time, and automatically replenishes the product when the remaining amount of the item falls below a preset threshold. You may place an order.

The destination information input unit 102 inputs destination information indicating the destination, such as an address, when the product ordering unit 101 orders a product. The destination information may be specified each time by the delivery service user, or the destination information input unit 102 may record destination information specified by the delivery service user in the past and input the destination information in the record. May be automatically reused.

Further, the destination information input unit 102 may use a GPS (Global Positioning System) positioning function provided in the user terminal 1 to set the current position acquired by GPS as the destination. Further, the destination information input unit 102 may add an image of the scenery around the user terminal 1 taken by the camera of the user terminal 1 to the destination information as reference information for the destination.

[Mobile robot]
The mobile robot 2 is a robot that can run autonomously. The mobile robot 2, for example, travels around town and delivers packages to a destination designated by a delivery service user.

The mobile robot 2 includes a current position acquisition unit 201, a wireless quality acquisition unit 202, a base station identification information (base station ID) acquisition unit 203, a status acquisition unit 204, a wireless communication unit 205, and a route information storage unit 206. , an imaging section 207 , a motion determination section 208 , and a motion control section 209 .

The current position acquisition unit 201 acquires the current position (position information) using a positioning system such as GPS. The wireless quality acquisition unit 202 acquires wireless communication quality (wireless communication quality information) when the wireless communication unit 205 performs wireless communication with the navigation device 4 for each wireless communication method and radio frequency band supported by the wireless communication unit 205. ) to obtain.

The base station ID acquisition unit 203 acquires the base station ID of each base station with which the mobile robot 2 (wireless communication unit 205) can establish a wireless communication connection. The base station ID is identification information that individually identifies each base station. An example of a base station ID is what is called a CID (Cell ID). Note that by combining the MCC (Mobile Country Code), MNC (Mobile Network Code), LAC (Location Area Code), and CID (Cell ID), it is possible to uniquely identify the base station of each country and each telecommunications carrier.

The status acquisition unit 204 acquires status data (status information) such as remaining battery power, temperature, and movement speed from various sensors included in the mobile robot 2 .

The wireless communication unit 205 performs wireless communication with the navigation device 4. The wireless communication unit 205 supports wireless communication systems such as LTE (Long Term Evolution) and 5G (fifth generation mobile communication system), and performs wireless communication via a base station of the wireless communication system that it supports. Furthermore, the wireless communication unit 205 may be compatible with an unlicensed wireless communication method such as Wi-Fi (registered trademark), and may perform wireless communication using the unlicensed wireless communication method.

The wireless communication unit 205 transmits information obtained by the current position acquisition unit 201, the wireless quality acquisition unit 202, the base station ID acquisition unit 203, and the status acquisition unit 204 to the operation monitoring unit 401 of the navigation device 4. Additionally, the wireless communication unit 205 receives route information transmitted from the route distribution unit 411 of the navigation device 4 and stores it in the route information storage unit 206. The route information stored in the route information storage unit 206 is utilized for determining the motion of the mobile robot 2.

Furthermore, the wireless communication unit 205 receives the wireless disconnection behavior information transmitted from the route distribution unit 411 of the navigation device 4 and stores it in the route information storage unit 206. The behavior information at the time of wireless disconnection describes the behavior that the mobile robot 2 takes when wireless communication is disconnected while the mobile robot 2 is moving along the route (initial route) indicated by the route information stored in the route information storage unit 206. This is the information shown. The behavior information at the time of wireless disconnection is, for example, route information indicating the route along which the mobile robot 2 moves when the wireless communication is disconnected (route at the time of wireless disconnection). The behavior information at the time of wireless communication is, for example, information indicating whether the mobile robot 2 should return to a point where it can resume movement or continue moving along the initial route when wireless communication is disconnected. The wireless disconnection behavior information stored in the route information storage unit 206 is used to determine the movement of the mobile robot 2 when wireless communication in the wireless communication unit 205 is disconnected. When the route information storage unit 206 detects the disconnection of wireless communication in the wireless communication unit 205, it transmits the behavior information at the time of wireless disconnection to the operation determination unit 208.

The imaging unit 207 images the moving direction of the mobile robot 2. The motion determining unit 208 determines the next motion of the mobile robot 2. The motion determining unit 208 uses the current position acquired by the current position acquisition unit 201, the captured image captured by the imaging unit 207, etc. when moving along the route indicated by the route information stored in the route information storage unit 206. Based on this, the mobile robot 2 determines its motion in accordance with the surrounding environment.

When the motion determination unit 208 receives the wireless disconnection behavior information from the route information storage unit 206 when disconnection of wireless communication in the wireless communication unit 205 is detected, the motion determination unit 208 determines the next behavior of the mobile robot 2 based on the wireless disconnection behavior information. Judging behavior.

The motion control unit 209 causes the mobile robot 2 to execute the motion determined by the motion determination unit 208. The motion control unit 209 controls the type and speed of movement of the mobile robot 2, such as forward movement, backward movement, and right/left turns, as well as the type of movement other than movement, such as changing the imaging direction of the imaging unit 207.

When the wireless communication in the wireless communication unit 205 is disconnected, the operation control unit 209 takes the action indicated by the wireless disconnection behavior information according to the determination result of the operation determination unit 208.

Here, with reference to FIG. 2, the action procedure of the mobile robot according to the present embodiment when wireless communication is disconnected will be explained. FIG. 2 is a flowchart illustrating an example of the action procedure of the mobile robot according to the present embodiment when wireless communication is disconnected.

(Step S101) The mobile robot 2 determines whether or not wireless communication has been disconnected. If wireless communication has been disconnected, the process proceeds to step S102. On the other hand, if wireless communication has not been disconnected, the process proceeds to step S103.

(Step S102) The mobile robot 2 takes action based on the action information at the time of wireless disconnection. For example, the mobile robot 2 autonomously travels along the wireless disconnection route indicated by the wireless disconnection behavior information.

(Step S103) The mobile robot 2 continues moving along the initial route indicated by the route information.

Note that the mobile robot 2 may further include a wireless disconnection cause determination unit that determines the cause of disconnection of wireless communication in the wireless communication unit 205. The motion determining unit 208 determines the next motion of the mobile robot 2 based on the behavior information at the time of wireless disconnection, in accordance with the determination result of the cause by the wireless disconnection cause determining unit. Therefore, the operation control unit 209 takes the action indicated by the wireless disconnection behavior information based on the determination result of the cause by the wireless disconnection cause determination unit. For example, if the cause of disconnection of wireless communication in the wireless communication unit 205 is interference by a large vehicle such as a truck, the wireless communication may be restored if the large vehicle moves. Therefore, if the cause of disconnection of wireless communication in the wireless communication unit 205 is interference by a large vehicle such as a truck, the action indicated in the behavior information at the time of wireless disconnection may include waiting at the current location for a certain period of time. .

[Mobile device]
The mobile terminal 3 is a mobile communication terminal device such as a smartphone or a tablet PC. The mobile terminal 3 may be used as the user terminal 1, or may be separate from the user terminal 1. The mobile terminal 3 may be, for example, the mobile terminals of all subscribers who have subscribed to a particular wireless communication carrier and who have agreed with the wireless communication carrier to acquire location information.

The mobile terminal 3 periodically reports the current position (position information) and the wireless communication quality (wireless communication quality information) at the current position to the navigation device 4 for each wireless communication method and radio frequency band that it supports. .

[Navigation device]
The navigation device 4 performs navigation for one or more mobile robots 2 from a starting point to a destination. Furthermore, the navigation device 4 performs operational monitoring of one or more mobile robots 2.

The navigation device 4 includes an operation monitoring section 401, an operation information storage section 402, a location/wireless quality/base station ID storage section 403, a map information storage section 404, a wireless quality movement cost calculation section 405, and a mobile terminal position storage section 403. Information storage section 406, outdoor population density estimation section 407, order information storage section 408, destination acquisition section 409, route search section 410, route distribution section 411, radio quality old and new comparison section 412, risk evaluation 413 , and a wireless disconnection behavior determination unit 414 .

The functions of the navigation device 4 are realized by the navigation device 4 being equipped with computer hardware such as a CPU (Central Processing Unit) and memory, and the CPU executing a computer program stored in the memory. The navigation device 4 may be configured using a general-purpose computer device, or may be configured as a dedicated hardware device. For example, the navigation device 4 may be configured using a server computer connected to a communication network such as the Internet. The functions of the navigation device 4 may be realized by cloud computing. The navigation device 4 may be realized by a single computer, or may be realized by distributing the functions of the navigation device 4 among multiple computers. The navigation device 4 may also be configured to set up a website using, for example, a WWW system.

The operation monitoring unit 401 monitors the operation of one or more mobile robots 2. The operation monitoring unit 401 performs operation monitoring by associating the position information, wireless communication quality information, and status information received from the mobile robot 2 in real time with information for identifying the individual mobile robot 2 (mobile robot ID). The operation monitoring unit 401 performs operation monitoring based on information (position information, wireless communication quality information, and status information) that is updated periodically, for example, at one-second intervals. The operation monitoring unit 401 analyzes the position information, wireless communication quality information, and status information received from the mobile robot 2, and when a failure of the mobile robot 2 is detected, issues an alarm to a supervisor, for example. The operation information storage unit 402 stores information (position information, wireless communication quality information, and status information) that the operation monitoring unit 401 receives from the mobile robot 2 in order to investigate the cause of a failure and consider future countermeasures.

The location/wireless quality/base station ID storage unit 403 stores location/wireless quality base station information in which location information, wireless communication quality information, and base station ID are recorded in association with each other for each wireless communication method and radio frequency band. .

The position information, wireless communication quality information, and base station ID recorded in the position wireless quality base station information are information transmitted from the mobile robot 2 or the mobile terminal 3 to the navigation device 4. Note that position information, wireless communication quality information, and base station ID measured by a device other than the mobile robot 2 or the mobile terminal 3 may be recorded in the position wireless quality base station information.

Further, the position information is, for example, GPS coordinates. For indoor facilities and the like where GPS coordinates cannot be acquired, absolute position information acquired by indoor positioning technology such as IMES (Indoor MEssaging System) may be used as the position information. Further, the wireless communication quality information is, for example, RSRP (Reference Signal Received Power) indicating received power of LTE.

The location wireless quality base station information may be provided for each date, day of the week, time period, or event. For example, location wireless quality base station information for weekdays (Monday to Friday) and location wireless quality base station information for holidays (Saturday, Sunday, and public holidays) may be provided. For example, location wireless quality base station information for daytime hours and location wireless quality base station information for nighttime hours may be provided. For example, location wireless quality base station information for New Year's Day, Golden Week, and Obon may be provided.

Fig. 3 is a diagram showing an example of the configuration of the position/wireless quality/base station ID storage unit 403 according to this embodiment. In the example of Fig. 3, the position/wireless quality/base station ID storage unit 403 stores, for the wireless communication method "LTE", position/wireless quality/base station information 4031 of wireless frequency band LTE_a and position/wireless quality/base station information 4032 of wireless frequency band LTE_b. In addition, for the wireless communication method "5G", the position/wireless quality/base station ID storage unit 403 stores, for the wireless communication method "5G", position/wireless quality/base station information 4033 of wireless frequency band 5G_a and position/wireless quality/base station information 4034 of wireless frequency band 5G_b.

For example, LTE uses radio frequency bands such as Band 1 (2.1 GHz) and Band 18 (800 MHz). For 5G, the 28 GHz band is used.

For example, the location wireless quality base station information 4031 is information in which the wireless communication quality and base station ID at each position_a, position_b, ... of the radio frequency band_LTE_a of the wireless communication system "LTE" are recorded in association with each other. . For example, the location wireless quality base station information 4033 is information in which the wireless communication quality and base station ID at each position_a, position_b, ... of the radio frequency band_5G_a of the wireless communication system "5G" are recorded in association with each other. .

Further, the location wireless quality base station information 4032 is information in which the wireless communication quality and base station ID at each position_a, position_b, ... of the radio frequency band_LTE_b of the wireless communication system "LTE" are recorded in association with each other. . In addition, in the location wireless quality base station information 4032, the same base station ID_LTE_b_ab is recorded in association with location_a and location_b. This is because in the radio frequency band _LTE_b of the wireless communication system "LTE", the base station with base station ID_LTE_b_ab was providing the wireless communication connection at the positions _a and _b at the time of measuring the wireless communication quality at the positions _a and _b. It is.

In the location wireless quality base station information, the base station ID is information that identifies a base station that provides wireless communication connection at the location associated with the base station ID. Furthermore, in the location wireless quality base station information, the base station ID identifies the base station that was providing wireless communication connection at the location associated with the base station ID at the time of measurement of the wireless communication quality at the location. It is information.

Note that in the location wireless quality base station information, the wireless communication quality and base station ID recorded in association with the position may be the base station ID of the base station that has obtained the best wireless communication quality at the position. Furthermore, in the location wireless quality base station information, the wireless communication quality and base station ID recorded in association with the location are the base station IDs and the wireless communication quality of all base stations from which wireless communication quality was obtained at the location. It may be.

In this embodiment, the position/wireless quality/base station ID storage unit 403 stores position/wireless quality/base station information of an area including at least the service target area of this delivery service system. The service target area of this delivery service system is an area (target area) for which the navigation device 4 provides route information. The position/wireless quality/base station ID storage unit 403 according to this embodiment stores position/wireless quality/base station information in which a position included in the target area is associated with the wireless communication quality and base station ID at that position and recorded for each wireless communication method (LTE, 5G, etc.) and wireless frequency band (wireless frequency band LTE_a, wireless frequency band LTE_b, wireless frequency band 5G_a, wireless frequency band 5G_b, etc.) for which wireless communication services are provided in the target area for which the navigation device 4 provides route information.

The map information storage unit 404 stores nationwide road map data and associated facility data such as various facilities and shops. The road map data is provided as link data in which roads on a map are divided into multiple parts with intersections and the like as nodes, and the parts between each node are defined as links. This link data includes data such as a link-specific identifier (link ID), link length, position information (longitude, latitude) of the start and end points (nodes) of the link, angle (direction) data, road width, and road type. The road map data may also include lane information indicating lanes that the mobile robot 2 can travel. The map information storage unit 404 may also store indoor map data.

The wireless quality movement cost calculation unit 405 calculates the wireless communication system and wireless quality base station based on each location wireless quality base station information stored for each wireless communication system and radio frequency band in the location/wireless quality/base station ID storage unit 403. For each frequency band, wireless communication quality information recorded in association with position information corresponding to each road is converted into a wireless quality link cost.

The wireless quality movement cost calculation unit 405 converts wireless communication quality information into a wireless quality link cost in response to a wireless quality link cost request from the route search unit 410. The wireless quality movement cost calculation unit 405 responds to the route search unit 410 with the wireless quality link cost.

For example, the wireless quality movement cost calculation unit 405 divides the value of the wireless quality link cost into three levels, and when the wireless communication quality is sufficiently good, the wireless quality link cost is set to "0", and when the wireless communication quality is not so high that the wireless communication is disconnected. When the wireless communication quality is poor, the wireless quality link cost is set to "large", and when there is a possibility that the wireless communication may be disconnected, the wireless quality link cost is set to "∞".

When the wireless communication quality is good enough, the possibility of wireless communication being disconnected is sufficiently low. For this reason, when a certain wireless communication quality is met that can be judged to be sufficiently unlikely to cause wireless communication to be disconnected (for example, when the received power is equal to or greater than a certain value), the wireless quality link cost may be made small (for example, the wireless quality link cost may be set to "0"), and when this is not the case, the wireless quality link cost may be made large (for example, the wireless quality link cost may be set to "large" or "∞").

For example, the wireless quality movement cost calculation unit 405 calculates a value near the lowest value of the wireless communication quality information, taking into account the lowest value of the wireless communication quality information and outliers, from among the wireless communication quality information group corresponding to each link data. The wireless quality link cost may be converted. This is to calculate the possibility that wireless communication will be disconnected when the mobile robot 2 travels on the road of the link data as a risk.

Note that the route search unit 410, which will be described later, sequentially calculates (integrates) the cost of the road (link) from the departure point to the destination until the next intersection (node) that can be reached. Select the route with the lowest cost to reach the destination. Therefore, if a small wireless quality link cost value is set for a road, that road will be more likely to be selected as a route.

The mobile terminal position information storage unit 406 stores the history of position information of each mobile terminal 3. For example, the GPS coordinates of each mobile terminal 3 are stored in association with time.

The outdoor population density estimation unit 407 determines whether each mobile terminal 3 was indoors or outdoors based on the history of the position information stored in the mobile terminal position information storage unit 406, and based on this determination result. Based on this, the outdoor population density is estimated for each preset area. Outdoor population density is the number of people per unit area outdoors. Information such as the outdoor population density determined by the outdoor population density estimating unit 407 is stored in the map information storage unit 404 in association with the corresponding link data in the road map data of the map information storage unit 404.

For example, the outdoor population density estimating unit 407 determines that the mobile terminal 3 is indoors when the change in location information is less than a certain value and is determined to be almost no change. If the value is above a certain level and it is determined that there has been a certain degree of change, it is determined that the person was outdoors.

In addition, the outdoor population density estimation unit 407 performs map matching by comparing the location information of each mobile terminal 3 with the road map data stored in the map information storage unit 404, and performs map matching to determine whether the mobile terminal 3 uses the road. It can be assumed that he did. Map matching is a process that uses map information to correct position information obtained by GPS, which may include errors, so that the position information is on the road. Map matching is used, for example, in car navigation systems.

Furthermore, the outdoor population density estimating unit 407 may determine, based on the moving speed of the mobile terminal 3, whether the means of transportation of the mobile terminal 3 is walking or a vehicle.

The outdoor population density estimation unit 407 may estimate the outdoor population density for each month, day of the week, and time period. This is because the outdoor population density may vary significantly depending on the month, day of the week, time period, etc., even in the same area.

The outdoor population density estimation unit 407 may also estimate the outdoor population density using a method other than the method using the location information of the mobile terminal 3. For example, the outdoor population density estimation unit 407 may use video captured by the mobile robot 2 and estimate the outdoor population density based on the results of image recognition of people in the captured video.

The order information storage unit 408 receives order information for ordering products from the user terminal 1 and stores the received order information. The order information storage unit 408 works in conjunction with a purchasing system (not shown) to carry out purchasing processing and formulate a product delivery plan. The order information storage unit 408 stores scheduled delivery information such as the departure point, destination, and time period for the mobile robot 2 to deliver the products according to the formulated product delivery plan. The destination acquisition unit 409 acquires destination information from the order information or scheduled delivery information stored in the order information storage unit 408.

The route search unit 410 searches for a route from the starting point of the mobile robot 2 to the destination as a route along which the mobile robot 2 is scheduled to travel. The destination of the mobile robot 2 is the location indicated by the destination information acquired by the destination acquisition unit 409. The starting point of the mobile robot 2 is set in advance. For example, a product delivery base (for example, a distribution warehouse where the product is stored, a delivery handling store closest to the destination, etc.) is set in advance as the departure point of the mobile robot 2. Further, when the mobile robot 2 is transported by a vehicle to the vicinity of the destination, the location of the transportation destination of the mobile robot 2 is set in advance as the departure point of the mobile robot 2.

As a route search method used by the route search unit 410, for example, Dijkstra's method, A* algorithm, genetic algorithm, etc. can be used.

The route search unit 410 calculates a total link cost for each link of each road based on the wireless quality link cost etc. as a conversion result of the wireless quality movement cost calculation unit 405. The route search unit 410 performs route search based on the total link cost. The route search unit 410 uses the wireless quality link cost and the information stored in the map information storage unit 404 to calculate the total link cost for each link on each road for each wireless communication method and radio frequency band. do.

The route search unit 410 weights each link on each road based on the wireless quality link cost so that poor wireless communication quality is given a low evaluation. For example, the route search unit 410 weights road links for which it is determined that there is a high possibility that wireless communication will be disconnected based on the wireless quality link cost so that the total link cost is the largest. Good too. This aims to realize stable wireless communication in the mobile robot 2.

The route search unit 410 may also calculate the overall link cost based on the outdoor population density. The route search unit 410 may weight the links of roads where the outdoor population density is equal to or greater than a threshold so that the overall link cost is large. This allows the mobile robot 2 to travel on roads with fewer people.

Further, the route search unit 410 may calculate the total link cost based on at least one of the type of mobile robot 2 and the content of delivery by the mobile robot 2, and the road condition of each link on each road. . The types of mobile robots 2 are classified according to the size, structure, etc. of the mobile robots 2. Further, the types of mobile robots 2 are classified according to the wireless communication method and radio frequency band that can be used by the mobile robots 2. The contents of the delivery by the mobile robot 2 include, for example, the type of cargo to be delivered by the mobile robot 2 and the expected loading amount.

For example, the route search unit 410 does not increase the total link cost because a small mobile robot 2 can safely travel on a link on a road with a road width less than a threshold, but a large mobile robot 2 In this case, increase the total link cost. In addition, since it is assumed that depending on the structure of the mobile robot 2, it may be difficult for the mobile robot 2 to overcome a step on the road, the route search unit 410 may be configured to On the other hand, increase the total link cost. Furthermore, when the type of cargo to be delivered by the mobile robot 2 is fragile, it is preferable to travel on a road with few unevenness, so the route search unit 410 reduces the total link cost of links on roads with few unevenness. On the other hand, the total link cost of links on roads with many unevenness is increased.

Additionally, the route search unit 410 may use evaluation factors used in known navigation systems as information used to calculate the total link cost. Evaluation factors used in known navigation systems include, for example, the required distance of a link, the time required for travel, weighting based on road conditions and road width, weighting based on signal frequency, weighting based on congestion tendency, and the like.

The route distribution unit 411 transmits route information indicating the route searched by the route search unit 410 to the mobile robot 2.

Here, the route search method according to this embodiment will be explained with reference to FIG. FIG. 4 is a flowchart illustrating an example of the procedure of the route search method according to the present embodiment.

(Step S1) The route search unit 410 acquires the starting point where the mobile robot 2 starts traveling and the destination where the mobile robot 2 is traveling.

(Step S2) The route search unit 410 acquires the type of mobile robot 2 and the details of the delivery.

(Step S3) The route search unit 410 recognizes the wireless communication method and wireless frequency band that can be used by the mobile robot 2 from the type of the mobile robot 2 acquired in step S2. The correspondence between the type of the mobile robot 2 and the available wireless communication method and wireless frequency band is set in advance in the navigation device 4.

(Step S4) The route search unit 410 specifies the search range including the departure point and destination of the mobile robot 2 acquired in step S1 to the wireless quality movement cost calculation unit 405, and searches each road within the search range. Request the radio quality link cost for each link in . The route search unit 410 receives the wireless quality link cost of each link of each road within the search range from the wireless quality movement cost calculation unit 405 as a response to the wireless quality link cost request.

The route search unit 410 calculates a total link cost for each link of each road within the search range for each wireless communication method and radio frequency band. In calculating this total link cost, each link on each road is weighted so that poor wireless communication quality results in a low evaluation. Note that if there are multiple wireless communication systems and radio frequency bands that can be used by the mobile robot 2, the route search unit 410 selects a wireless communication system that provides the best wireless communication quality for each link on each road. and only the total link cost for the radio frequency band may be calculated.

(Step S5) The route search unit 410 calculates a route from the starting point to the destination based on the total link cost calculated in step S4, with respect to the starting point and destination of the mobile robot 2 obtained in step S1. Explore. In this route search, a search is performed for a route that minimizes the total link cost of each link passed from the starting point to the destination.

(Step S6) The route distribution unit 411 transmits route information indicating the route searched for in step S5 to the mobile robot 2.

FIG. 5 is an explanatory diagram for explaining an example of a route search method. FIG. 6 is an explanatory diagram for explaining the route searching method according to this embodiment. In FIGS. 5 and 6, circles indicate nodes, and lines connecting nodes indicate links. Further, the starting point node is S, and the destination node is G. Further, the number written on the link indicates the link cost. FIG. 5 shows link costs when wireless communication quality is not considered. On the other hand, FIG. 6 shows the total link cost according to the present embodiment when wireless communication quality is taken into consideration. Further, here, it is assumed that the link L2 has poor wireless communication quality and there is a high possibility that the wireless communication will be disconnected.

In the case of the link costs in FIG. 5, as a result of the route search, the route from the departure point "Node S" to the destination "Node G" is "L1 → L2 → L3", which is the route with the minimum total link cost. is selected. Since the link cost in FIG. 5 does not take wireless communication quality into consideration, link L2 with a high possibility of wireless communication being disconnected is selected as the route. As a result, if the wireless communication between the mobile robot 2 and the navigation device 4 is cut off on the selected route, the mobile robot 2 may become unable to be remotely monitored.

On the other hand, in FIG. 6, a total link cost "4+∞", which is the sum of the radio quality link cost "∞" and the link cost "4" in FIG. 5, is set for the link L2. As a result, according to the total link cost shown in FIG. 6, link L2, which has a high possibility of wireless communication being disconnected, is not selected as a route. In the case of the link costs in FIG. 6, as a result of the route search, the route from the departure point "Node S" to the destination "Node G" is "L4→L5", which is the route with the minimum total link cost. is selected. According to this selected route "L4→L5", it is possible to realize stable wireless communication in the mobile robot 2. Thereby, the mobile robot 2 can be stably monitored remotely through wireless communication.

The explanation returns to FIG. 1.
The wireless quality old and new comparison unit 412 compares the current wireless communication quality at the current position of the mobile robot 2 monitored by the operation monitoring unit 401 and the position wireless quality stored in the position/wireless quality/base station ID storage unit 403. Compare the wireless communication quality at a location corresponding to the current location in the base station information. The timing of this comparison is the timing when the mobile robot 2 moves toward the destination. The timing at which the mobile robot 2 moves toward the destination is the timing at which the mobile robot 2 starts delivery, the timing at which the mobile robot 2 is moving for delivery, or the like. In other words, the wireless quality old and new comparison unit 412 compares the past wireless communication quality recorded in the location wireless quality base station information in the area where the mobile robot 2 makes deliveries and the wireless quality at the timing when the mobile robot 2 actually makes deliveries. Compare communication quality. Thereby, it can be determined whether or not the wireless communication quality at the timing when the mobile robot 2 actually makes a delivery has deteriorated compared to the past wireless communication quality.

The risk evaluation unit 413 evaluates the risk of disconnection of wireless communication for each location. The risk evaluation unit 413 uses the change status of wireless communication quality acquired by the old and new wireless quality comparison unit 412 and the position wireless information stored in the position/wireless quality/base station ID storage unit 403 corresponding to the movement route of the mobile robot 2. Based on the quality base station information, the total link cost calculated by the route search unit 410, etc., the risk in the case where wireless communication is disconnected on the movement route of the mobile robot 2 is evaluated.

The risk evaluation unit 413 performs risk evaluation in real time at short intervals and updates the risk evaluation results. The update interval of the risk evaluation results is, for example, every 10 seconds.

(Example of risk assessment method)
An example of a risk evaluation method in the risk evaluation section 413 will be explained.
The risk evaluation unit evaluates the estimated continuous distance of wireless disconnection and the difficulty level when the mobile robot 2 autonomously moves over the estimated continuous distance of wireless disconnection. The estimated wireless disconnection continuation distance is an estimated value of the distance over which wireless communication will continue to be disconnected if wireless communication is disconnected.

The risk evaluation unit 413 determines the estimated distance of continuous wireless disconnection based on the location/wireless quality base station information stored in the location/wireless quality/base station ID storage unit 403. Specifically, the risk evaluation unit 413 determines whether the mobile robot 2 is in a section where the same base station ID as the base station ID of the position where wireless communication is assumed to be disconnected (assumed disconnection position) continues on the movement route of the mobile robot 2; The distance of the section where there is no other base station ID different from the base station ID is determined as the estimated wireless disconnection continuation distance. Further, among the sections, the distance of only the section where the wireless communication quality is worse than the assumed disconnection position may be determined as the estimated wireless disconnection continuation distance.

The risk evaluation unit 413 uses the size of the evaluation link cost for a certain distance as the size of the risk. The evaluation link cost is based on factors other than the wireless quality link cost, such as road conditions, road width, outdoor population density, type of mobile robot 2, delivery details (type of cargo, expected loading amount, etc.), and road surface conditions. It is weighted according to If the total link cost includes factors other than those radio quality link costs, the total link cost may be used as the evaluation link cost.

A road with a large evaluation link cost compared to the length of the road has a high degree of difficulty for the mobile robot 2 to move autonomously. Therefore, this road is a road where there is a high risk of autonomous movement of the mobile robot 2, which is in a state where wireless communication is cut off and remote monitoring is not possible.

For example, suppose the evaluation link cost is 1 when the mobile robot 2 moves autonomously along a road that is 100 meters (m) long and there is no particular danger. Then, a road that is 200 m long and has an evaluation link cost of 4 is a road that is difficult for the mobile robot 2 to move autonomously along. The magnitude of the evaluation link cost (magnitude of risk) for a certain distance (for example, 100 m) on this road is "4/(200 m/100 m) = 2".

The risk evaluation unit 413 calculates a risk evaluation value using, for example, the following equation (1).

Risk evaluation value = "estimated distance of continued wireless disconnection" x "size of evaluation link cost for a certain distance (size of risk)" ... (1)

In equation (1) above, if the estimated continuous distance of wireless disconnection is converted to "1" per 100m, then if the estimated continuous distance of wireless disconnection is 300m and the risk size is 2, the risk evaluation value becomes “3×2=6”.

Note that the evaluation link cost is preferably updated in real time. For example, the evaluation link cost may be updated in accordance with a real-time outdoor population density update result by the outdoor population density estimation unit 407.

The wireless disconnection behavior determination unit 414 determines the behavior of the mobile robot 2 when wireless communication is interrupted while the mobile robot 2 is moving along a path indicated in the path information. The path distribution unit 411 transmits in advance to the mobile robot 2 behavior information during wireless disconnection indicating the behavior of the mobile robot 2 determined by the wireless disconnection behavior determination unit 414.

(Example of how to decide on behavior when wireless is disconnected)
An example of a method for determining behavior at wireless disconnection in the wireless disconnection behavior determination unit 414 will be described.
The wireless disconnection behavior determination unit 414 determines the behavior that the mobile robot 2 will take based on the risk evaluation value that is the risk evaluation result of the risk evaluation unit 413.

For example, the wireless disconnection behavior decision unit 414 has multiple candidate behaviors set in advance, performs a threshold judgment on the risk assessment value, and selects an action from the multiple candidate behaviors according to the threshold judgment result. As a specific example, if the risk assessment value exceeds a predetermined threshold, the wireless disconnection behavior decision unit 414 determines the behavior of the mobile robot 2 to return to a point where it can resume its movement, and on the other hand, if the risk assessment value does not exceed the threshold, determines the behavior of continuing movement along the path indicated in the path information even after wireless communication is disconnected. Note that if the mobile robot 2 returns to a point where it can resume its movement, the path search unit 410 searches for an alternative path from the return point where it can resume its movement to the destination. Updated path information indicating the alternative path as a result of the search may be included in the wireless disconnection behavior information in advance and transmitted to the mobile robot 2.

Note that action candidates are not limited to the above-mentioned ``return to a point where movement can be resumed'' or ``continue movement along the route indicated in the route information,'' but may be any action candidate that is appropriate when wireless communication is disconnected. Bye.

Furthermore, when the mobile robot 2 disconnects the wireless communication, the mobile robot 2 may determine the cause of the wireless communication being disconnected, and the mobile robot 2 may determine its own behavior based on the result of determining the cause. In this case, the wireless disconnection behavior determination unit 414 includes behavior candidates for each cause of wireless communication disconnection in the wireless disconnection behavior information. The mobile robot 2 takes an action corresponding to the determination result of the cause of the disconnection of wireless communication from among the action candidates in the action information at the time of wireless disconnection. For example, if the cause of disconnection of wireless communication is interference by a large vehicle such as a truck, the action indicated in the behavior information at the time of wireless disconnection may include waiting at the current location for a certain period of time.

The judgment threshold of the risk evaluation value is based on the magnitude of the impact when the state of the mobile robot 2 including its position cannot be remotely monitored due to disconnection of wireless communication, and the time it takes to reach the destination. There is a trade-off relationship with travel time. Therefore, the determination threshold of the risk evaluation value may be determined depending on which of the two is considered more important by the operator.

The behavior information at the time of wireless disconnection is transmitted in advance to the mobile robot 2 by the route distribution unit 411. Thereby, even if the wireless communication with the navigation device 4 is interrupted, the mobile robot 2 can act autonomously based on the wireless disconnection behavior information received and held in advance.

According to the embodiment described above, it is possible to provide route information for realizing stable wireless communication in the mobile robot 2. Furthermore, if the wireless communication is cut off, the mobile robot 2 can take appropriate measures.

Although the embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like may be made without departing from the gist of the present invention.

In the embodiment described above, the navigation system is applied to the delivery service system, but it may be applied to other systems other than the delivery service system. For example, the navigation system according to the embodiment described above may be applied to a road inspection service system that inspects roads using a mobile robot.

Further, in the above-described embodiment, a mobile robot is used as an example of a mobile object, but the present invention is not limited to this. As the moving object, a vehicle that performs self-driving (self-driving vehicle), a flying object that flies autonomously, etc. may be applied.

Further, a computer program for realizing the functions of each device described above may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read into a computer system and executed. Note that the "computer system" here may include hardware such as an OS and peripheral devices.
Furthermore, "computer-readable recording media" refers to flexible disks, magneto-optical disks, ROMs, writable non-volatile memories such as flash memory, portable media such as DVDs (Digital Versatile Discs), and media built into computer systems. A storage device such as a hard disk.

Furthermore, the term "computer-readable recording medium" includes devices that retain a program for a certain period of time, such as volatile memory (e.g., DRAM (Dynamic Random Access Memory)) within a computer system that serves as a server or client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line.
The program may be transmitted from a computer system in which the program is stored in a storage device or the like to another computer system via a transmission medium, or by a transmission wave in the transmission medium. Here, the "transmission medium" that transmits the program refers to a medium that has a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
The program may be a program for implementing some of the above-mentioned functions, or may be a so-called differential file (differential program) that can implement the above-mentioned functions in combination with a program already recorded in the computer system.

1... User terminal, 2... Mobile robot, 3... Mobile terminal, 4... Navigation device, 10... Navigation system, 401... Operation monitoring section, 402... Operation information storage section, 403... Location/wireless quality/base station ID storage Department, 404...Map information storage unit, 405...Wireless quality movement cost calculation unit, 406...Mobile terminal location information storage unit, 407...Outdoor population density estimation unit, 408...Order information storage unit, 409...Destination acquisition unit, 410 ...Route search section, 411...Route distribution section, 412...Wireless quality old and new comparison section, 413...Risk evaluation section, 414...Wireless disconnection behavior determination section

Claims (9)

A navigation device that provides route information indicating a route from a departure point to a destination for a moving object whose remote monitoring is performed via a wireless communication line,
a location wireless quality information storage unit that stores location wireless quality information in which a location and wireless communication quality at the location are recorded in association with each other;
a route search unit that searches for the route from among the route candidates based on the location radio quality information stored in the location radio quality information storage unit;
a wireless disconnection action determination unit that determines an action to be taken by the mobile body when wireless communication is disconnected while the mobile body is moving along the route;
a transmitter that transmits in advance wireless disconnection behavior information indicating the behavior of the mobile body determined by the wireless disconnection behavior determination unit to the mobile body;
A risk evaluation unit that evaluates the risk of disconnection of wireless communication for each location,
The wireless disconnection action determining unit determines the action to be taken by the mobile body based on the risk evaluation result of the risk evaluation unit,
The risk evaluation unit evaluates an estimated wireless disconnection continuation distance, which is an estimated value of a distance over which wireless communication will continue to be disconnected when wireless communication is disconnected.
navigation device. The risk evaluation unit further evaluates the difficulty level when the mobile object autonomously moves through the estimated wireless disconnection continuation distance.
2. The navigation device of claim 1. The wireless disconnection action determining unit includes:
If the risk assessment result exceeds a predetermined threshold, the moving object decides to return to a point where it can resume movement;
On the other hand, if the risk evaluation result does not exceed the threshold, the action is determined to continue moving along the route even after wireless communication is disconnected;
The navigation device according to claim 1 or 2 . The location wireless quality information storage unit stores location wireless quality base station information in which base station identification information identifying a base station that provides wireless communication connection at each location is recorded in association with the location wireless quality information;
The risk evaluation unit determines the estimated wireless disconnection continuation distance based on the location wireless quality base station information.
A navigation device according to any one of claims 1 to 3 . The mobile object is a mobile object that performs delivery,
The route is a route along which the mobile unit delivers the information.
A navigation device according to any one of claims 1 to 4 . A mobile body that moves based on route information provided by the navigation device according to any one of claims 1 to 5 ,
a wireless communication unit that performs wireless communication with the navigation device;
an information storage unit that stores behavior information at the time of wireless disconnection received in advance from the navigation device;
a control unit that causes an action indicated by the wireless disconnection behavior information when wireless communication in the wireless communication unit is disconnected;
A mobile body equipped with. further comprising a wireless disconnection cause determination unit that determines the cause of disconnection of wireless communication in the wireless communication unit,
The control unit takes the action indicated in the wireless disconnection action information based on the determination result of the cause by the wireless disconnection cause determination unit.
The moving body according to claim 6 . A navigation method for providing route information indicating a route from a departure point to a destination to a mobile object, the mobile object being remotely monitored via a wireless communication line,
a position/wireless quality information storage step of storing, in a position/wireless quality information storage unit, position/wireless quality information in which a position and a wireless communication quality at the position are associated with each other and recorded;
a route searching step of searching for the route from among the route candidates based on the position and radio quality information stored in the position and radio quality information storage unit;
a wireless disconnection time behavior determination step of determining a behavior to be taken by the moving object when wireless communication is disconnected while the moving object is moving along the route;
a transmitting step of transmitting, in advance to the moving body, behavior information during wireless communication disconnection, which indicates the behavior of the moving body determined in the behavior determination step during wireless communication disconnection;
A risk assessment step of assessing a risk of wireless communication being disconnected for each location,
The wireless disconnection behavior decision step decides a behavior to be taken by the moving object based on a result of the risk assessment in the risk assessment step,
The risk assessment step includes evaluating an estimated wireless disconnection duration distance, which is an estimated value of a distance over which the wireless communication disconnection will continue when the wireless communication is disconnected.
Navigation methods. a computer of a navigation device that provides route information indicating a route from a departure point to a destination for a mobile object whose remote monitoring is performed via a wireless communication line;
a location wireless quality information storage step of storing location wireless quality information in which a location and wireless communication quality at the location are recorded in association with each other in a location wireless quality information storage unit;
a route searching step of searching for the route from among the route candidates based on the location radio quality information stored in the location radio quality information storage unit;
a wireless disconnection behavior determining step of determining an action to be taken by the mobile body when wireless communication is disconnected while the mobile body is moving along the route;
a transmitting step of transmitting in advance to the mobile body wireless disconnection behavior information indicating the behavior of the mobile body determined in the wireless disconnection behavior determining step;
a risk evaluation step of evaluating the risk of disconnection of wireless communication for each location;
is a computer program that runs
The step of determining the action at the time of wireless disconnection determines the action to be taken by the mobile body based on the risk evaluation result of the risk evaluation step,
The risk evaluation step evaluates an estimated wireless disconnection continuation distance, which is an estimated value of the distance over which wireless communication will continue to be disconnected when wireless communication is disconnected.
computer program.

Images