Snow removal schedule estimation system

Abstract

To provide a technology capable of improving accuracy of estimating snow removal schedule time.SOLUTION: A snow removal schedule time estimation system includes: a current location acquisition unit that acquires a current location of a snow removal vehicle; a traveling scheduled route acquisition unit that acquires a traveling scheduled route of the snow removal vehicle; and a snow removal schedule time estimation unit that estimates the time when the snow removal vehicle travels along a road section included in the traveling scheduled route based on the current location and the traveling scheduled route and acquires the time as snow removal schedule time for the road section.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a scheduled snow removal time estimation system.

Background Art

[0002] Conventionally, techniques for providing information related to snow removal vehicles are known. For example, Patent Document 1 discloses a technique for displaying the next scheduled snow removal time by a snow removal vehicle on a map. Furthermore, Patent Document 1 also discloses a technique for displaying the speed of a snow removal vehicle on a map in order to avoid traffic congestion caused by the snow removal vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The above-described conventional technique is configured to display the next scheduled snow removal time on a map, but the calculation method for the scheduled snow removal time is not embodied at all, and thus the scheduled snow removal time is considered to be merely a predetermined schedule. However, work performed by snow removal vehicles does not always proceed as scheduled. For this reason, conventionally, it has been difficult to know the accurate scheduled snow removal time for each road. The present invention was made in view of the aforementioned problems, and aims to provide a technique capable of increasing the possibility that the estimation accuracy of scheduled snow removal time is improved.

Means for Solving the Problems

[0005] To achieve the above objective, the snow removal schedule time estimation system comprises: a current position acquisition unit that acquires the current position of a snowplow; a planned route acquisition unit that acquires the planned route of the snowplow; and a snow removal schedule time estimation unit that estimates the time when the snowplow will travel through the road section included in the planned route, based on the current position and the planned route, and acquires this as the planned snow removal time for the road section.

[0006] In the snow removal schedule estimation system, the time at which the snowplow will travel along a road section included in the planned route is estimated based on the snowplow's current position and planned route. In other words, the snow removal schedule estimation system estimates the time at which the snowplow will travel along an arbitrary road section after its current position as the scheduled snow removal time, based on the snowplow's current position and the route it will travel after its current position. Therefore, even if the progress of the work by the snowplow changes due to speeding up or slowing down, the progress of the work is reflected in the estimation after the current position. As a result, it is possible to increase the likelihood of improving the accuracy of the snow removal schedule estimation. [Brief explanation of the drawing]

[0007] [Figure 1] This diagram shows the configuration of the snow removal schedule estimation system. [Figure 2] Figures 2A and 2B are explanatory diagrams illustrating the current location and planned route of the snowplow. [Figure 3] This is a flowchart for estimating the scheduled time for snow removal. [Modes for carrying out the invention]

[0008] The embodiments will be described in the following order. (1) Configuration of the snow removal schedule estimation system: (2) Processing to estimate the scheduled time for snow removal: (3) Other embodiments:

[0009] (1) Configuration of the snow removal schedule estimation system: Figure 1 is a block diagram showing the configuration of the snow removal schedule time estimation system 20. In this embodiment, the snow removal schedule time estimation system 20 cooperates with an in-vehicle system 10, a weather information management system 30, and a user terminal 40. The in-vehicle system 10 is mounted on a snowplow. The in-vehicle system 10 is a system that collects the driving history of the snowplow and transmits the driving history to the snow removal schedule time estimation system 20.

[0010] The weather information management system 30 is a system for collecting and storing weather information. In this embodiment, the weather information includes snowfall. In this embodiment, the weather information is defined for each pre-defined region. The region may be defined by various methods, and in this embodiment, the weather information is defined for each mesh, which is a rectangle of a predetermined size.

[0011] In this embodiment, snowfall is expressed as the amount of snow accumulation per hour. The weather information management system 30 collects weather information from the present and previous periods and stores it in a storage medium (not shown). Since weather information changes with time, the weather information management system 30 stores each hourly weather information from the present and previous periods in the storage medium, associating it with a specific time. The weather information management system 30 can transmit weather information for any given time to the snow removal schedule time estimation system 20 in response to a request for weather information transmission from the snow removal schedule time estimation system 20.

[0012] The user terminal 40 is a terminal for displaying the scheduled snow removal times for each road section. Users who wish to display the amount of snowfall operate the user terminal 40 to instruct the display of the scheduled snow removal times for each road section. In response to this operation, the user terminal 40 outputs a request to the snow removal schedule estimation system 20 to transmit the scheduled snow removal times along with the road sections to be displayed. In response to this request, the snow removal schedule estimation system 20 obtains the scheduled snow removal times for the road sections to be displayed and transmits them to the user terminal 40. The user terminal 40 is equipped with a display unit (not shown) and displays the obtained scheduled snow removal times in association with the road sections. The display method of the scheduled snow removal times can be in various forms; for example, the scheduled snow removal times may be displayed on a map in association with the road sections, or the scheduled snow removal times may be displayed as a pop-up in response to an operation on the map in which a road section is specified. The latter embodiment is assumed here.

[0013] In Figure 1, one in-vehicle system 10 and one user terminal 40 are shown, but the snow removal schedule estimation system 20 can receive detection results from multiple in-vehicle systems 10. Furthermore, the snow removal schedule estimation system 20 can output the snow removal schedule to multiple user terminals 40.

[0014] The in-vehicle system 10 includes a control unit 11 equipped with a CPU, RAM, ROM, etc., a recording medium 12, a communication unit 13, a GNSS receiver 14, a vehicle speed sensor 15, and a gyro sensor 16. Map information 121 is recorded on the recording medium 12. The communication unit 13 is a device for wireless communication with external devices. Information transmission and reception between the control unit 11 and the snow removal schedule estimation system 20 is performed via the communication unit 13. The GNSS receiver 14 is a device for receiving signals from the Global Navigation Satellite System. The GNSS receiver 14 receives radio waves from navigation satellites and outputs a signal for calculating the position of the snowplow via an interface (not shown). The control unit 11 acquires this signal to obtain the position of the snowplow.

[0015] The vehicle speed sensor 15 outputs a signal corresponding to the rotational speed of the wheels of the snowplow. The control unit 11 acquires this signal via an interface (not shown) and obtains the vehicle speed. The gyro sensor 16 detects the angular acceleration of the snowplow's turning in the horizontal plane and outputs a signal corresponding to the snowplow's orientation. The control unit 11 acquires this signal and obtains the snowplow's direction of travel. The vehicle speed sensor 15 and the gyro sensor 16 are used to determine the snowplow's travel trajectory. The travel trajectory is corrected based on the snowplow's position obtained based on the output of the GNSS receiver 14.

[0016] In this embodiment, the control unit 11 performs map matching processing based on the position of the snowplow acquired based on the output of the GNSS receiver 14, the snowplow's travel trajectory after a predetermined point, and the map information 121. Once the map matching processing is performed, it is determined whether or not the snowplow is on a link (road section). If the snowplow is on a link, the control unit 11 identifies the link on which the snowplow is located. The map information 121 is the same information as the map information 222 described later.

[0017] The control unit 11 can execute various programs stored in the recording medium 12 or ROM. In this embodiment, the control unit 11 can execute a driving history transmission program 110 as one of these programs. Through processing the driving history transmission program 110, the control unit 11 acquires the driving history 122 of the snowplow, associates it with the snowplow's identification information, and transmits it to the snowplow scheduled time estimation system 20 via the communication unit 13.

[0018] In the present embodiment, the travel history 122 includes a history of the position of the snowplow for each time, and the link subjected to map matching. Therefore, the control unit 11 acquires the position of the snowplow for each time through map matching processing, and associates the position of the snowplow with the time. Further, when the snowplow is on the link identified by the map matching processing, the control unit 11 refers to the map information 121 to identify the identification information of the link indicating the road section where the snowplow is located. Then, the control unit 11 associates the identification information of the link where the position is located with the position of the snowplow.

[0019] Next, the scheduled snow removal time estimation system 20 will be described. The scheduled snow removal time estimation system 20 includes a control unit 21 equipped with a CPU, a RAM, a ROM, etc., a recording medium 22, and a communication unit 23. The communication unit 23 is a device for performing wireless communication with an external device. Transmission and reception of information between the in-vehicle system 10, the weather information management system 30, the user terminal 40, and the scheduled snow removal time estimation system 20 are performed via the communication unit 23.

[0020] The travel history 122, planned travel route information 221, map information 222, and scheduled snow removal time information 223 are recorded in the recording medium 22. The travel history 122 is information transmitted from the in-vehicle system 10. However, the travel histories 122 transmitted from a plurality of snowplows are recorded in the recording medium 22 of the scheduled snow removal time estimation system 20. That is, the control unit 21 acquires the travel history 122 periodically transmitted from the in-vehicle system 10, and records it in the recording medium 22 in association with the identification information of the snowplow that is the transmission source.

[0021] The map information 222 includes node data indicating the positions of nodes corresponding to the endpoints of road sections, shape interpolation point data indicating the positions of shape interpolation points for specifying the shape of roads between nodes, link data indicating links connecting nodes, facility data indicating facilities existing around road sections, and the like. Here, the nodes correspond to intersections, and the links correspond to road sections from one intersection to another. In addition, information such as the position, name, and attribute of a facility is associated with the facility data.

[0022] The planned travel route information 221 is information indicating a planned travel route of the snow removal vehicle. In the present embodiment, the planned travel route information 221 is information indicating information (link ID) representing road segments constituting the planned travel route, and the order of traveling on each road segment. The planned snow removal time information 223 is information indicating a planned snow removal time for each road segment.

[0023] The control unit 21 can execute various programs stored in the recording medium 22 or the ROM. The control unit 21 of the present embodiment can execute a planned snow removal time estimation program 210 as this program. Through the processing of the planned snow removal time estimation program 210, the control unit 21 functions as a current position acquisition unit 211, a planned travel route acquisition unit 212, a snow accumulation amount estimation unit 213, and a planned snow removal time estimation unit 214.

[0024] The current position acquisition unit 211 has a function of acquiring the current position of the snow removal vehicle. Specifically, the in-vehicle system 10 transmits the travel history 122 to the planned snow removal time estimation system 20 at regular intervals. The planned snow removal time estimation system 20 acquires the transmitted travel history 122 and records it in the recording medium 22. The transmission interval of the travel history 122 from the in-vehicle system 10 is a predetermined short interval, and the position of the snow removal vehicle included in the latest travel history 122 can be regarded as the current position of the snow removal vehicle. Accordingly, the control unit 21 refers to the recording medium 22, and acquires the current position of the snow removal vehicle and the road segment on which the vehicle is traveling, based on the latest travel history 122 of the snow removal vehicle.

[0025] The number of snow removal vehicles performing work simultaneously is arbitrary, but here, for simplicity, a state is assumed in which one snow removal vehicle is working in the target area for which the planned snow removal time is to be estimated. FIG. 2A is a diagram showing the current position P of the snow removal vehicle and roads in its periphery. In FIG. 2A, roads are indicated by thin lines, and the planned travel route is indicated by thick solid lines and broken lines. The solid lines are assumed to represent road segments where the snow accumulation amount is less than a threshold value, and the broken lines are assumed to represent road segments where the snow accumulation amount is equal to or greater than the threshold value. Further, in the example shown in FIG. 2A, the snow removal vehicle present at the current position P is shown traveling toward the lower right while performing snow removal work.

[0026] The planned route information 221 is a function that acquires the planned route of the snowplow. That is, the control unit 21 refers to the recording medium 22 and acquires the planned route information 221 which shows the planned route of the snowplow traveling on the road section for which the snow removal schedule time is to be estimated. In the example shown in Figure 2A, the route of the snowplow traveling at the current position P is road sections L1 to L4, and the control unit 21 acquires these road sections L1 to L4 and also acquires that the travel order is L1, L2, L3, L4.

[0027] The snow depth estimation unit 213 is a function that estimates the amount of snow on the planned route based on the history of snow removal along the planned route and the amount of snowfall. When snow removal is performed, the amount of snow on the road immediately returns to an initial value (for example, 0 cm, a few cm, etc.), and the amount of snow is determined by the amount of snowfall after that. If snow removal is not performed, the amount of snow is determined by the amount of snowfall since the start of the snowfall.

[0028] Therefore, the control unit 21, using the function of the snow depth estimation unit 213, refers to the travel history 122 and obtains the snow removal history. That is, the control unit 21 refers to the travel history 122 and identifies the link that the snowplow traveled, i.e., the section that was cleared. At this time, the control unit 21 refers to the travel history 122 and identifies the time when the snowplow traveled the link. If the snowplow has traveled the same link multiple times, the control unit 21 identifies the time when the snowplow last traveled the road section indicating the link. In cases where the snowplow traveled the road section but simply passed through without clearing snow, the presence or absence of snow removal is associated with the travel history 122, and the control unit 21 refers only to the history where snow removal was performed. Furthermore, in road sections where two-way traffic is possible, the control unit 21 independently obtains the time when snow removal was performed for each direction.

[0029] Furthermore, the control unit 21 acquires the amount of snowfall in the cleared section using the function of the snow depth estimation unit 213. That is, the control unit 21 sends a request to the weather information management system 30 to transmit the amount of snowfall in the area including the cleared section. In response to the transmission request, the weather information management system 30 replies to the snow removal schedule time estimation system 20 with the amount of snowfall in the area including the cleared section. The control unit 21 acquires the amount of snowfall via the communication unit 23 and records it in RAM or the like (not shown).

[0030] The control unit 21 then estimates the amount of snow in the cleared section based on the amount of snowfall, using the function of the snow depth estimation unit 213. Specifically, the snow depth estimation unit 213 obtains the amount of snow by accumulating the product of the amount of snowfall and the duration of snowfall at that amount. The method for calculating the duration of snowfall varies depending on whether or not snow removal has been performed. For road sections that have not been cleared, it is the period from the start of snowfall to the present. For sections that have been cleared, it is the period from the time of the last snow removal to the present.

[0031] Furthermore, snow depth may be corrected using various methods. For example, based on weather information, corrections may be made so that lower temperatures result in greater snow depth. Also, corrections may be made so that lower humidity results in greater snow depth. In addition, corrections may be made to account for snow that has accumulated on the side of the road due to snow removal and falls onto the road, such as corrections so that stronger winds result in greater snow depth, or corrections so that narrower roads result in greater snow depth.

[0032] The snow removal schedule estimation unit 214 estimates the time at which the snowplow will travel through the road sections included in the planned route, based on the snowplow's current position and planned route, and obtains this as the scheduled snow removal time for each road section. In this embodiment, the control unit 21 estimates the travel speed of the snowplow for each road section using the function of the snow removal schedule estimation unit 214. The control unit 21 also accumulates the time required to travel through each road section at the said travel speed and adds it to the current time to obtain the scheduled snow removal time for each road section.

[0033] In this embodiment, the snowplow's travel speed is a predetermined standard speed, but it is adjusted according to the amount of snow. The travel speed of a regular vehicle when traveling on a road without snow can vary depending on road characteristics, etc. However, in the case of a snowplow, since it travels while performing snow removal work, in this embodiment, no difference in travel speed due to road characteristics, etc. occurs, and it is considered to be the standard travel speed.

[0034] However, since the ease of snow removal may differ depending on whether the amount of snow is heavy or light, in this embodiment, the travel speed is corrected according to the amount of snow. That is, when acquiring the travel speed, the control unit 21 sets the travel speed of the snowplow to a lower speed in sections where the amount of snow is above a threshold than in sections where the amount of snow is below a threshold. The threshold only needs to be predetermined, and in this embodiment, it is a value such that the travel speed is not affected if the amount of snow does not exceed the threshold, but decreases when it exceeds the threshold. Such an amount of snow is predetermined by statistics or the like and is set as the threshold. The control unit 21 then sets the travel speed in sections where the amount of snow is below the threshold to the standard speed, and the travel speed in sections where the amount of snow is above the threshold to a travel speed lower than the standard speed. In this embodiment, the travel speed when set to a speed lower than the standard travel speed is a predetermined value.

[0035] As described above, once the snow removal schedule is estimated, the estimated snow removal schedule is associated with identification information indicating the road section and recorded on the recording medium 22 as snow removal schedule information 223. The user operates the user terminal 40 at any time to instruct the display of the snow removal schedule for each road section. In response to this operation, the user terminal 40 outputs a request for the snow removal schedule along with the road section to be displayed to the snow removal schedule estimation system 20. In response to this request, the snow removal schedule estimation system 20 obtains the snow removal schedule for the road section to be displayed and transmits it to the user terminal 40. The transmitted snow removal schedule is displayed on the display unit of the user terminal 40.

[0036] In the user terminal 40, assuming a configuration where a map as shown in Figure 2A is displayed on the display unit, the user can tap a road section on the display unit to instruct the display of the scheduled snow removal time. In Figure 2A, it is assumed that road section L4 is tapped. In this case, the user terminal 40 outputs a request to send the scheduled snow removal time for road section L4. The snow removal scheduled time estimation system 20 obtains the scheduled snow removal time for road section L4 in response to the request and sends it back to the user terminal 40. As a result, the scheduled snow removal time, such as 13:30, is displayed in a pop-up box B as exemplified in Figure 2A on the display unit of the user terminal 40. According to this embodiment, the user can find out the scheduled snow removal time for a desired road section. Furthermore, in this embodiment, the time at which the snowplow reaches the target road section from its current position via the planned route is estimated based on the driving speed for each road section. Therefore, compared to a configuration in which a predetermined fixed time is used as the scheduled snow removal time, it is possible to increase the possibility of improving the accuracy of the snow removal scheduled time estimation.

[0037] (2) Processing to estimate the scheduled time for snow removal: Figure 3 is a flowchart showing the snow removal schedule time estimation process. In this embodiment, multiple snowplows transmit their driving history 122 at arbitrary timings. The control unit 21 receives the driving history 122 and records it sequentially on the recording medium 22. As the driving history 122 is recorded in this manner, the control unit 21 performs the snow removal schedule time estimation process at regular intervals. The length of the regular interval is not limited, but in this embodiment, the length is set such that the value obtained as a result of the snow removal schedule time estimation process can be considered as the snow removal schedule time estimated from the current position of the snowplow.

[0038] When the snow removal schedule time estimation process is started, the control unit 21 acquires links that constitute the planned route of the snowplow (step S100). As described above, in this embodiment, it is assumed that one snowplow is in operation. Therefore, the control unit 21 acquires links that constitute the planned route of the snowplow. For this purpose, the control unit 21 uses the function of the current position acquisition unit 211 to refer to the travel history 122 to which the identification information of the snowplow in operation is associated, and acquires the current position of the snowplow. Furthermore, the control unit 21 uses the function of the travel schedule information 221 to refer to the travel schedule information 221 to which the identification information of the snowplow is associated, and acquires links that indicate the road sections that constitute the travel schedule information 221 after the current position of the snowplow in operation.

[0039] Next, the control unit 21 acquires the travel history of the link acquired in step S100 (step S105). In this embodiment, it is assumed that one snowplow is in operation, but after the start of snowfall, before the said snowplow starts working, other snowplows may be working, and in this case, the presence or absence of snow removal may differ for each link acquired in step S100. Therefore, the control unit 21 refers to the travel history 122 and, if there is a history of traveling along the link acquired in step S100, acquires that history, that is, the time when the road section indicated by the link was cleared of snow.

[0040] Next, the control unit 21 performs the loop processing steps S110 to S150 on each of the links acquired in step S105. In step S110, the control unit 21 selects from the links acquired in step S100 any unprocessed links that have not yet been processed in steps S110 to S150 as targets for processing. Here, the control unit 21 processes the links in order of their proximity to the current position of the snowplow currently in operation.

[0041] Next, the control unit 21 determines, using the function of the snow removal scheduled time estimation unit 214, whether or not a snowplow has traveled through the road section indicated by the link to be processed (step S115). That is, the control unit 21 refers to the travel history acquired in step S105 and determines whether or not there is a travel history associated with the same identification information as the identification information of the link to be processed. If a travel history exists, the control unit 21 considers the road section indicated by the link to be processed to be a snow-cleared section. The control unit 21 also identifies the time when snow removal was performed based on the travel history. If there is no travel history associated with the same identification information as the identification information of the link to be processed, the control unit 21 considers the link to be processed to be not a snow-cleared section.

[0042] If, in step S115, it is determined that a snowplow has traveled on the road section indicated by the link to be processed, the control unit 21 estimates the amount of snow since the start of snowfall using the function of the snow depth estimation unit 213 (step S120). That is, the control unit 21 uses the function of the snow depth estimation unit 213 to obtain information from the weather information management system 30 indicating the amount of snowfall for each time period prior to the present, and identifies the time when the snow started falling and the amount of snowfall for each time period since the start of snowfall. The control unit 21 then estimates the amount of snow by accumulating the product of the amount of snowfall and the duration of snowfall at that amount. For example, if 3 hours have passed since the start of snowfall, and the amount of snowfall in the first hour was 5 cm / hour, and the amount of snowfall in the next 2 hours was 10 cm / hour, the control unit 21 estimates the amount of snow to be 25 cm by 1 × 5 + 2 × 10 = 25.

[0043] On the other hand, if it is determined in step S115 that a snowplow has traveled through the road section indicated by the link to be processed, the control unit 21 resets the snow depth using the function of the snow depth estimation unit 213 (step S125). That is, the control unit 21 obtains the time when the snowplow passed through the section indicated by the link to be processed and returns the snow depth at that time to its initial value.

[0044] Next, the control unit 21 estimates the amount of snow accumulated since the last time the snowplow passed through, using the function of the snow accumulation estimation unit 213 (step S130). Specifically, the control unit 21 refers to the travel history acquired in step S105 and identifies the time when the snowplow last passed through (passed through while clearing snow) the section indicated by the link to be processed. The control unit 21 also refers to information indicating the amount of snowfall for each time period prior to the present, using the function of the snow accumulation estimation unit 213, and identifies the amount of snowfall after the time when the snowplow last passed through the section indicated by the link to be processed. The control unit 21 then estimates the amount of snow by accumulating the product of the amount of snowfall and the duration of snowfall at that amount. For example, if 2 hours have passed since the last time a snowplow passed through the section indicated by the link to be processed, and the snowfall in the first hour was 10 cm / hour, and the snowfall in the next hour was 15 cm / hour, and the initial value is 5 cm, the control unit 21 estimates the snow depth to be 30 cm by calculating 1 × 10 + 1 × 15 + 5 = 30.

[0045] Next, the control unit 21 estimates the snowplow's travel speed from the amount of snow using the function of the snow removal scheduled time estimation unit 214 (step S135). That is, the control unit 21 determines whether the amount of snow estimated in step S120 or step S130 is above a threshold. If the amount of snow is below the threshold, it estimates that the snowplow's travel speed is a predetermined standard travel speed. If the amount of snow is above the threshold, it estimates that the snowplow's travel speed is a predetermined value lower than the standard travel speed.

[0046] Next, the control unit 21 estimates the travel time based on the travel speed using the function of the snow removal schedule time estimation unit 214 and obtains it as the snow removal schedule time (step S140). That is, the control unit 21 obtains the required time from the current position of the snowplow to the road section indicated by the link to be processed, and obtains the snow removal schedule time by adding it to the current time. As described above, in the loop processing of steps S110 to S150, the links to be processed are selected in order of proximity to the current position of the snowplow.

[0047] For example, in the example shown in Figure 2A, when the loop processing of steps S110 to S150 is performed for the first time while the snowplow is at its current position P, the link to be processed is the link indicating road section L1. As mentioned above, the amount of snow in road section L1 is below the threshold. Therefore, when step S135 is performed when road section L1 is the link to be processed, the control unit 21 considers the driving speed in road section L1 to be the reference driving speed. Then, in step S140, the control unit 21 obtains the distance of road section L1 by referring to map information 222 and obtains the required time to travel through road section L1 by dividing the distance by the reference driving speed. In this case, the current time + required time is the scheduled time for snow removal in road section L1. In other words, in this embodiment, the time when snow removal in road section L1 will be completed is estimated as the scheduled time for snow removal.

[0048] Next, when the loop processing of steps S110 to S150 is performed, the link indicating road section L2 becomes the link to be processed. As mentioned above, the amount of snow in road section L2 is above the threshold. Therefore, when step S135 is performed when road section L2 is the link to be processed, the control unit 21 considers the driving speed in road section L2 to be a value lower than the reference driving speed. Then, in step S140, the control unit 21 obtains the distance of road section L2 by referring to the map information 222, and obtains the required time to travel through road section L2 by dividing the distance by a value lower than the reference driving speed. In this case, the current time + required time for road section L1 + required time for road section L2 is the scheduled snow removal time for road section L2. In this way, when the scheduled snow removal time is obtained in step S140, the identification information of the road section is associated with it and recorded in the recording medium 22 as scheduled snow removal time information 223.

[0049] Next, the control unit 21 determines whether the loop processing from steps S110 to S155 has finished for all the links acquired in step S100 (step S150), and repeats the processing from step S110 onward until it is determined that the loop has finished.

[0050] (3) Other embodiments: The above embodiments are merely examples for carrying out the present invention, and various other embodiments can be adopted. For example, the snow removal scheduled time estimation system 20 may be a system implemented by multiple devices. At least a portion of the current position acquisition unit 211, the planned travel route acquisition unit 212, the snow depth estimation unit 213, and the snow removal scheduled time estimation unit 214 that constitute the snow removal scheduled time estimation system 20 may be divided among multiple devices. Of course, some of the configurations of the above embodiments may be omitted, and the order of processing may be changed or omitted.

[0051] For example, at least some of the functions of the current location acquisition unit 211, the planned route acquisition unit 212, the snow depth estimation unit 213, and the snow removal scheduled time estimation unit 214 may be executed by the in-vehicle system 10 or the user terminal 40. Furthermore, if the difference in driving speed due to the difference in snow depth is not large, the correction due to the snow depth may be omitted. In addition, various configurations can be adopted for acquiring the snow depth. For example, the snow depth may be acquired from the weather information management system 30.

[0052] The current location acquisition unit only needs to be able to acquire the current location of the snowplow. In other words, the current location acquisition unit only needs to be able to acquire the current location of the snowplow that is capable of performing work on the road section for which the snow removal schedule is to be estimated. If there are multiple snowplows performing snow removal work, the current location may be acquired for each snowplow, and the acquisition of the current location may be omitted for snowplows that are not traveling on the road section for which the snow removal schedule is to be estimated.

[0053] The planned route acquisition unit only needs to acquire the planned route of the snowplow. That is, the planned route that the snowplow will travel while clearing snow is predetermined, and each snowplow will clear snow while traveling along that planned route. The planned route may be defined in various ways; for example, the planned route may be defined by the starting point of snow removal, the ending point of snow removal, and the names of the roads to be traveled between these points.

[0054] The snow removal schedule estimation unit should estimate the time when the snowplow will travel through the road section included in the planned route, based on its current location and planned route, and obtain this as the scheduled snow removal time for that road section. In other words, the snow removal schedule estimation unit estimates the time when the snowplow will reach and travel through any road section on the planned route, assuming it travels along the planned route while performing snow removal as appropriate, starting from its current location.

[0055] The scheduled snow removal time only needs to be defined in a way that allows for recognition of the time when snow removal will take place. It may be the scheduled completion time, the scheduled start time, or a time between the two. For example, if the scheduled snow removal time is the scheduled completion time, the time of completion of passage through the road section is obtained and considered the scheduled snow removal time. If the scheduled snow removal time is the scheduled start time, the time of arrival at the road section is obtained and considered the scheduled snow removal time.

[0056] The time of travel through a road section can be any time it takes to reach any road section along the planned route, assuming the vehicle travels along the planned route from its current location. Various methods can be used to estimate this time. For example, the speed of a snowplow may depend on factors other than the amount of snow. Specifically, the time of travel through a road section may be estimated based on the travel speed, which depends on factors such as road congestion and road characteristics.

[0057] The travel speed may change in multiple stages or continuously depending on the amount of snow. In this case, for example, in the embodiment described above, the snow removal scheduled time estimation unit 214 may adopt a configuration that sets the travel speed of the snowplow to a lower speed in sections with more snow. The travel speed corresponding to the amount of snow is predetermined, and the control unit 21 acquires the corresponding travel speed according to the amount of snow in step S135. With this configuration, the snow removal scheduled time estimation can be estimated by more accurately reflecting the travel speed of the snowplow that changes according to the amount of snow.

[0058] Furthermore, while the above-described embodiment assumed a situation where one snowplow was operating simultaneously, multiple snowplows may be operating at the same time. In this case, for example, in the above-described embodiment, the snow depth estimation unit 213 is configured to acquire the latest snow removal history on the planned route based on the snow removal history of multiple snowplows.

[0059] Figure 2B shows an example where multiple snowplows C1 and C2 are present and working simultaneously. Here, solid lines are assumed to represent road sections with snow depths below a threshold, and dashed lines are assumed to represent road sections with snow depths above a threshold. In this example, the planned route for snowplow C1 is road sections L1, L2, L3, and L4, and the planned route for snowplow C2 is road sections L5, L3, and L6. Furthermore, it is assumed that snowplow C2 reaches road section L3 first and performs snow removal, and then snowplow C1 reaches road section L3 and performs snow removal.

[0060] In this case, the estimated time for snow removal can be estimated using various methods. For example, it can be achieved by performing the snow removal time estimation process shown in Figure 3 for each snowplow. Specifically, for example, a configuration can be adopted in which the snow removal time estimation process is performed for each snowplow at regular intervals (for example, each time the current position of the snowplow is updated). In this configuration, once snow removal of a road section is completed by each snowplow, the current position of the snowplow in the travel history 122 will indicate that it has passed through that road section. Therefore, the travel history 122 acquired in step S105 indicates that snow removal of that road section has been completed. Accordingly, after the determination in step S115, the amount of snow in that road section is reset in step S125.

[0061] For example, in the example shown in Figure 2B, we assume the state after snowplow C2 has cleared snow from road sections L5 and L3. In this state, we assume that snowplow C1 is continuing its snow removal work and is clearing snow from road section L2. In this state, since snow removal from road section L3 is complete, the amount of snow in road section L3 is reset in step S125. In this case, when snowplow C1 travels through road section L3, the amount of snow does not increase much, and in step S130, the amount of snow in road section L3 is estimated to be below the threshold. As a result, in step S135, the travel speed of snowplow C1 in road section L3 is estimated to be low, and based on this low travel speed, the estimated snow removal time in step S140 is performed. Therefore, compared to a configuration that estimates the snow removal time by snowplow C1 without considering snow removal by snowplow C2, the snow removal time can be estimated more accurately (as an earlier time in this example). Figure 2B shows an example where the scheduled snow removal time of 13:00 is displayed in pop-up box B.

[0062] The above process is just one example of how to handle situations where multiple snowplows are operating simultaneously, and various other processes can be employed. For example, before the snowplows actually perform snow removal, the order in which snow removal will be performed on any road section from the planned route can be identified, the amount of snow accumulation can be estimated according to that order, and the travel speed can be estimated. For example, in the example shown in Figure 2B, snowplow C2 reaches road section L3 before snowplow C1. Therefore, it can be determined that any road section to be cleared by both snowplows C1 and C2 will be cleared in the order of snowplow C2, then snowplow C1.

[0063] Therefore, by estimating the scheduled time for snow removal by snowplow C2 on the road section based on the planned route of snowplow C2, it is possible to estimate the amount of snow when snowplow C1 reaches the road section based on the elapsed time from that scheduled snow removal time. By performing this process, it is possible to evaluate the impact of snow accumulation on the driving speed even before actual snow removal is carried out, and to estimate the scheduled snow removal time based on the driving speed. Of course, the number of snowplows operating simultaneously can be more than two. In any case, by estimating the scheduled snow removal time for the snowplow that will perform snow removal first, and then estimating the scheduled snow removal time for each snowplow in the order in which they will perform snow removal, it is possible to estimate the scheduled snow removal time while considering the impact of snow removal by any number of snowplows.

[0064] Furthermore, the above-described system can also be applied as a program or method. Such programs and methods may be implemented as a single device, or as a combination of multiple devices using shared components, encompassing various forms. They can also be modified as needed, such as being partly software and partly hardware. Moreover, the invention also exists as a recording medium for a program that controls the system. Of course, this recording medium could be a magnetic recording medium, a semiconductor memory, or any recording medium developed in the future; the same principle applies. [Explanation of symbols]

[0065] 10...In-vehicle system, 11...Control unit, 12...Recording medium, 13...Communication unit, 14...GNSS receiver, 15...Vehicle speed sensor, 16...Gyro sensor, 20...Snow removal scheduled time estimation system, 21...Control unit, 22...Recording medium, 23...Communication unit, 30...Weather information management system, 40...User terminal, 110...Driving history transmission program, 121...Map information, 122...Driving history, 210...Snow removal scheduled time estimation program, 211...Current location acquisition unit, 212...Driving route acquisition unit, 213...Snow depth estimation unit, 214...Snow removal scheduled time estimation unit, 221...Driving route information, 222...Map information, 223...Snow removal scheduled time information

Claims

1. A current position acquisition unit that acquires the current position of the snowplow, A unit for acquiring the planned route of the snowplow, A snow depth estimation unit estimates the amount of snow on the planned route based on the snow removal history and snowfall amount along the planned route. A snow removal schedule time estimation unit estimates the time at which the snowplow will travel through the road section included in the planned route, based on the current location and the planned route, and obtains this as the planned snow removal time for the road section. Equipped with, The snow removal scheduled time estimation unit is, In sections where the snow depth exceeds a threshold, the snowplow's travel speed is set lower than in sections where the snow depth is below the threshold, and the time required for each section at each travel speed is accumulated to estimate the scheduled snow removal time. A system for estimating the scheduled time for snow removal.

2. The snow removal scheduled time estimation unit is, The more snow accumulation there is in a section, the lower the speed of the snowplow will be set. The snow removal schedule estimation system according to claim 1.

3. The aforementioned snowplows are operating in multiple units simultaneously. The snow depth estimation unit acquires the latest snow removal history on the planned route based on the snow removal history of multiple snowplows. The snow removal schedule estimation system according to claim 1.

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