Loading determination device, program, and loading determination method

Abstract

A load determination device, program, and load determination method are provided that can determine with high accuracy whether a vehicle is loaded or not based on the temperature inside the tires. [Solution] The loading determination device (10) includes an acquisition unit (131) that acquires input data including the internal tire temperature and ambient temperature for the front and rear wheels of the vehicle, respectively, detected by a detection device mounted on the vehicle; a calculation unit (132) that calculates the natural cooling temperature after a certain period of time based on the ambient temperature difference, which is the temperature difference between the internal tire temperature and the ambient temperature, and the cooling coefficient of the vehicle's tires, and calculates the degree of heat generation for the front and rear wheels of the vehicle over a certain period of time based on the calculated natural cooling temperature and the internal tire temperature after a certain period of time; and a determination unit (133) that performs a first determination to determine whether or not the vehicle is loaded based on the degree of heat generation of the rear wheels of the vehicle relative to the degree of heat generation of the front wheels of the vehicle.

Description

Technical Field

[0004] , , , , ,

[0005] , , ,

[0003] , , , ,

[0001] The present disclosure relates to a loading determination device, a program, and a loading determination method.

Background Art

[0002] Conventionally, methods for managing the state of tires of a vehicle during travel have been proposed. For example, Patent Document 1 discloses a tire deterioration state prediction method for predicting the deterioration state of a tire by a computer using a tire model composed of a plurality of elements. In addition, the state of the vehicle (for example, whether or not it is loaded) has also been determined from the state of the tire.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, it is possible to determine whether or not a vehicle is loaded (that is, whether the vehicle is in a loaded state or an empty state) using the temperature inside the tire as the state of the tire. The temperature inside the tire can be obtained from, for example, a tire pressure monitoring system (TPMS) mounted on the vehicle. Here, as a result of the inventor's intensive investigation regarding the temperature inside the tire, it has been found that the temperature inside the tire affected by the environment during stoppage (including a lot of noise) is detected during travel after a short stoppage of the vehicle. If the measured temperature inside the tire is inaccurate, the determination accuracy of whether or not it is loaded decreases.

[0005] In view of such circumstances, an object of the present disclosure is to provide a loading determination device, a program, and a loading determination method capable of determining whether or not a vehicle is loaded with high accuracy based on the temperature inside the tire.

Means for Solving the Problems

[0006] (1) A loading determination device according to one embodiment of the present disclosure is An acquisition unit that acquires input data including the internal tire temperature and ambient temperature for the front and rear wheels of the vehicle, respectively, as detected by a detection device mounted on the vehicle, A calculation unit calculates the natural cooling temperature after a certain period of time based on the temperature difference between the temperature inside the tire and the ambient temperature, which is the temperature difference between the ambient temperature and the temperature inside the tire, and the cooling coefficient of the vehicle's tire, and calculates the degree of heat generation for the front and rear wheels of the vehicle during that certain period of time based on the calculated natural cooling temperature and the temperature inside the tire after that certain period of time. The system includes a determination unit that performs a first determination to determine whether or not the vehicle is loaded, based on the degree of heat generation of the rear wheels of the vehicle relative to the degree of heat generation of the front wheels of the vehicle. This configuration allows for highly accurate determination of whether a vehicle is loaded or not based on the temperature inside the tires.

[0007] (2) As one embodiment of the present disclosure, in (1), If the input data includes the tire temperature and the outside air temperature for a period exceeding a predetermined time after the vehicle starts driving, The calculation unit calculates only the difference in ambient temperature based on the temperature inside the tire and the ambient temperature after a certain period of time has elapsed since the vehicle started driving. The determination unit performs a second determination to determine whether or not the vehicle is loaded, based on the difference in ambient temperature between the rear wheels of the vehicle and the difference in ambient temperature between the front wheels of the vehicle. This configuration allows for highly accurate determination of whether a vehicle is loaded or not based on the tire temperature, while reducing the computational load.

[0008] (3) As one embodiment of the present disclosure, in (2), The predetermined time is set such that the slope of the difference in ambient temperature at the rear wheels of the vehicle relative to the difference in ambient temperature at the front wheels of the vehicle can be calculated using the difference in ambient temperature after a certain period of time has elapsed since the vehicle started moving. This configuration allows the above-mentioned predetermined time to be set appropriately.

[0009] (4) In one embodiment of the present disclosure, in any of (1) to (3), The aforementioned fixed time is set as the time until the effects of the noise are eliminated by the vehicle driving. This configuration allows for the appropriate setting of the aforementioned time interval.

[0010] (5) A program according to one embodiment of the present disclosure is In the load determination device, The system acquires input data, including the internal tire temperature and ambient temperature for the front and rear wheels of the vehicle, as detected by a detection device mounted on the vehicle. Based on the temperature difference between the temperature inside the tire and the ambient temperature, which is the ambient temperature difference, and the cooling coefficient of the vehicle's tires, the natural cooling temperature after a certain period of time is calculated, and based on the calculated natural cooling temperature and the temperature inside the tire after the certain period of time, the degree of heat generation for the front and rear wheels of the vehicle during that certain period of time is calculated. A first determination is made to determine whether or not the vehicle is loaded, based on the degree of heat generated by the rear wheels of the vehicle relative to the degree of heat generated by the front wheels of the vehicle. This configuration allows for highly accurate determination of whether a vehicle is loaded or not based on the temperature inside the tires.

[0011] (6) A loading determination method according to one embodiment of the present disclosure is A loading determination method performed by a loading determination device, The aforementioned load determination device, Obtaining input data including the in-tire temperature and the outside air temperature for each of the front and rear wheels of the vehicle detected by a detection device mounted on the vehicle; Calculating a natural cooling temperature after a certain period of time based on the outside air temperature difference, which is the temperature difference between the in-tire temperature and the outside air temperature, and the cooling coefficient of the vehicle's tires, and calculating the degree of heat generation for each of the front and rear wheels of the vehicle at the certain time based on the calculated natural cooling temperature and the in-tire temperature after the certain period of time; Performing a first determination for determining whether the vehicle is loaded based on the degree of heat generation of the rear wheels of the vehicle with respect to the degree of heat generation of the front wheels of the vehicle. With this configuration, it is possible to determine whether the vehicle is loaded with high accuracy based on the in-tire temperature.

Effect of the Invention

[0012] According to the present disclosure, it is possible to provide a load determination device, a program, and a load determination method capable of determining whether a vehicle is loaded with high accuracy based on the in-tire temperature.

Brief Description of the Drawings

[0013] [Figure 1] FIG. 1 is a diagram showing a configuration example of a load determination system including a load determination device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is another diagram showing a configuration example of the load determination system of FIG. 1. [Figure 3] FIG. 3 is a diagram for explaining the classification of the mounting positions of the tires. [Figure 4] FIG. 4 is a diagram for explaining the difference in the distributed temperature of the temperature of the rear wheel tire with respect to the temperature of the front wheel tire. [Figure 5] FIG. 5 is a diagram showing an example of the change in the outside air temperature difference between the front and rear wheels of the vehicle after the start of travel. [Figure 6] FIG. 6 is a diagram for explaining the first determination. [Figure 7]FIG. 7 is a diagram showing another example of the change in the outside air temperature difference between the front and rear wheels of a vehicle after the start of travel. [Figure 8] FIG. 8 is a diagram for explaining the second determination. [Figure 9] FIG. 9 is an example of a flowchart showing the processing of the loading determination method according to an embodiment of the present disclosure.

MODE FOR CARRYING OUT THE INVENTION

[0014] Hereinafter, a loading determination device 10 (see FIG. 1), a program, and a loading determination method according to an embodiment of the present disclosure will be described with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals. In the description of the present embodiment, the description of the same or corresponding parts will be omitted or simplified as appropriate.

[0015] FIGS. 1 and 2 are diagrams showing a configuration example of a loading determination system including the loading determination device 10 according to the present embodiment. FIG. 1 is a block diagram including an internal configuration example of the loading determination device 10 and a configuration example of a device mounted on the vehicle 20. FIG. 2 shows the overall configuration of the loading determination system.

[0016] The load determination device 10 according to this embodiment determines whether the vehicle 20 is loaded or not. The determination of whether the vehicle 20 is loaded or not may be one of two states: loaded to nearly the maximum load capacity (full load) or loaded to nearly zero (empty load). The load determination device 10 is not limited to simply indicating whether or not the vehicle is loaded, but may also indicate numerical values ​​related to the condition of the tires 30 based on the determination result, so that the manager of the vehicle 20 can decide, for example, whether or not to replace, repair, or rotate the tires 30 to change their mounting position. Repair of the tires 30 may include retreading, which involves grinding down the surface of the tread rubber of the tire 30 and attaching new rubber for reuse (reuse). The numerical values ​​related to the condition of the tires 30 may be, for example, the cumulative time of full load. For example, the manager of the vehicle 20 may decide to replace some or all of the tires 30 when the cumulative time of full load of the vehicle 20 exceeds a standard time. Here, the vehicle 20 may be, for example, a passenger car, a truck, a bus, or a construction vehicle, and is not limited to a specific type of mobile body. In this embodiment, the vehicle 20 is described as a truck that transports cargo. Also, in order to avoid duplication of illustrations in Figures 1 and 2, only one vehicle 20 is shown, but the load determination system may be configured to include multiple vehicles 20.

[0017] The load determination device 10 comprises a communication unit 11, a storage unit 12, and a control unit 13. The control unit 13 comprises an acquisition unit 131, a calculation unit 132, a determination unit 133, and an output unit 134. The load determination device 10 may be, for example, a computer as its hardware configuration. The computer may be a server computer or a portable computer such as a laptop or tablet. Details of the components of the load determination device 10 will be described later. In this embodiment, the load determination device 10 is a computer in a management facility that manages the status of the vehicle 20 (a truck that transports cargo) and the tires 30. Here, the load determination device 10 is not a single device, but may consist of multiple devices arranged in multiple locations that can send and receive data from each other via a network 40. In other words, multiple devices connected by the network 40 may function as a whole as the load determination device 10 shown in Figure 1. Therefore, for example, the load determination device 10 may consist of a single computer as its hardware configuration, or it may consist of multiple computers connected by a network 40. In the case of a system composed of multiple computers, the storage unit 12 may be a shared memory accessible by each computer.

[0018] The load determination device 10 may constitute a load determination system together with devices mounted on a vehicle 20 connected via a network 40 (detection device 70 and in-vehicle communication device 80). The network 40 is, for example, the Internet. The network 40 may also be configured to include, for example, a LAN (Local Area Network) in part. Here, the load determination system may further include a terminal device 50 used by an administrator (the person in charge of the management facility who manages the status of the vehicle 20 and the tires 30). The terminal device 50 is, for example, a general-purpose mobile terminal such as a smartphone or tablet terminal, but is not limited to these. The terminal device 50 may function as a display unit that displays the determination result output by the output unit 134. The load determination system may also include a storage device 90 (a cloud-based storage device 90) located on the network 40 as viewed from the load determination device 10 and the devices mounted on the vehicle 20. In this embodiment, the storage device 90 includes a database that stores information regarding the status of the tires 30 detected by the detection device 70 mounted on the vehicle 20 as time-series data, linked to the vehicle 20 that is the target of detection. Furthermore, in this embodiment, the load determination device 10 acquires information regarding the state of the tires 30 from a database via the network 40 as input information.

[0019] In this embodiment, the vehicle 20 includes a detection device 70 and an in-vehicle communication device 80. The detection device 70 is a device or in-vehicle system equipped with sensors that generates information regarding the state of the tires 30. In this embodiment, the detection device 70 is configured to include a tire pressure monitoring system (TPMS). The detection device 70 also includes a device for detecting the ambient temperature in the environment in which the tires 30 are used. The ambient temperature may be detected by the tire pressure monitoring system and another device (e.g., an ambient temperature gauge), or by the tire pressure monitoring system.

[0020] The tire pressure monitoring system monitors the pressure (internal pressure) and temperature (internal tire temperature) of the tire 30 mounted on the vehicle 20. The tire pressure monitoring system may be configured to include, for example, a sensor installed inside the tire 30, a processor that calculates and outputs the pressure of the tire 30 based on the sensor's detected values, and a memory that stores the sensor's detected values. The sensor may include a pressure sensor and a temperature sensor. The temperature sensor may include a sensor installed inside the tire 30 to detect the internal tire temperature, as well as a sensor installed on the outer surface of the tire 30 to detect the ambient temperature.

[0021] The in-vehicle communication device 80 is a device that outputs information regarding the state of the tires 30 detected by the detection device 70, so that it is stored in a database. In this embodiment, the in-vehicle communication device 80 is implemented by the communication function of a digital tachograph, but is not limited to this, and may be, for example, a dedicated communication device. In this embodiment, the in-vehicle communication device 80 outputs information on at least the internal tire temperature and the ambient temperature, and this information is stored in a database of the storage device 90 on the cloud.

[0022] The components of the load determination device 10 are described below in detail. The communication unit 11 is composed of one or more communication modules connected to the network 40. The communication unit 11 may include communication modules that support mobile communication standards such as 4G (4th Generation) and 5G (5th Generation). The communication unit 11 may also include communication modules that support wired or wireless LAN standards.

[0023] The storage unit 12 is one or more memories. The memories are, for example, semiconductor memories, magnetic memories, or optical memories, but are not limited to these and can be any memory. The storage unit 12 is, for example, built into the loading determination device 10, but it is also possible to configure it to be accessed externally by the loading determination device 10 via any interface.

[0024] The storage unit 12 stores various data used in various calculations performed by the control unit 13. The storage unit 12 may also store the results and intermediate data of various calculations performed by the control unit 13.

[0025] In this embodiment, the storage unit 12 may temporarily store various information from the database of the storage device 90 on the cloud, which is acquired via the communication unit 11. The storage unit 12 may also store vehicle information, which is information related to the vehicle 20 (for example, axle configuration).

[0026] The control unit 13 is one or more processors. The processors are, for example, general-purpose processors or dedicated processors specialized for specific processing, but are not limited to these and can be any processor. The control unit 13 controls the overall operation of the load determination device 10.

[0027] Here, the load determination device 10 may have the following software configuration. One or more programs used to control the operation of the load determination device 10 are stored in the storage unit 12. When the programs stored in the storage unit 12 are read by the processor of the control unit 13, the control unit 13 is made to function as an acquisition unit 131, a calculation unit 132, a determination unit 133, and an output unit 134.

[0028] The acquisition unit 131 acquires input data, including the tire temperature and ambient temperature, detected by the detection device 70 mounted on the vehicle 20. In this embodiment, the input data is acquired as time-series data associated with the time when the tire temperature and ambient temperature were detected. Here, the input data includes the tire temperature for the front and rear wheels of the vehicle 20, respectively.

[0029] Here, if the vehicle 20 is a four-wheeled truck (see Figure 2), the two tires 30 on the left and right sides in the direction of travel are classified as front wheels, and the two tires 30 on the left and right sides in the direction of travel are classified as rear wheels. Figure 3 is a diagram for illustrating the classification of the mounting positions of the tires 30, and shows a bird's-eye view of a 12-wheeled (left) and a 10-wheeled (right) vehicle 20. The tires 30 at mounting positions P1, P2, P7, and P8 are front wheels. The tires 30 at mounting positions P3-P6 and P9-P12 are rear wheels. In this embodiment, the mounting positions of the tires 30 are not individual positions, but are classified as either front wheels or rear wheels, where the magnitude of the load on the tires 30 differs. Here, the mounting positions and number of tires 30 can be obtained, for example, from vehicle information.

[0030] The calculation unit 132 calculates the natural cooling temperature after a certain period of time based on the ambient temperature difference, which is the temperature difference between the temperature inside the tire and the ambient temperature, and the cooling coefficient of the tires 30 of the vehicle 20. The calculation unit 132 also calculates the degree of heat generation for the front and rear wheels of the vehicle 20 over a certain period of time, based on the calculated natural cooling temperature and the temperature inside the tire after a certain period of time. As will be described in detail later, the calculated degree of heat generation is used in the first determination by the determination unit 133.

[0031] Furthermore, if the input data includes the tire temperature and ambient temperature for a period exceeding a predetermined time after the vehicle 20 starts driving, the calculation unit 132 may exclude a portion of the input data and calculate only the ambient temperature difference. In other words, the calculation unit 132 may calculate only the ambient temperature difference based on the tire temperature and ambient temperature after a certain period of time has elapsed since the vehicle 20 started driving. As will be described in detail later, the calculated ambient temperature difference is used in the second determination by the determination unit 133.

[0032] Here, a method for determining whether a vehicle 20 is loaded or unloaded based on the temperature inside the tires is explained. Figure 4 is a diagram illustrating the difference in temperature distribution between the front and rear tires. The left side of Figure 4 shows the temperature distribution of the rear tires relative to the temperature of the front tires. Representative values ​​may be used for the front tires. For example, for multiple front tires, the one with the highest median temperature may be considered the reference front tire. Then, by plotting the temperature of multiple rear tires at the same time point relative to the temperature of the reference front tire at a given time point, for multiple time points, a distribution like the left side of Figure 4 is obtained. Here, the reference line is a straight line with Y=X, where the horizontal axis is the X-axis and the vertical axis is the Y-axis. In vehicle 20, which is a truck transporting cargo, the weight (load) on the front tires is large. The load on the rear tires is smaller than that on the front tires, and the load is especially small when the vehicle is empty or has a small load. Therefore, when vehicle 20 is empty, the temperature distribution of the rear tires is as shown in the lower right side of Figure 4. In other words, there are no plots in the region close to the baseline (R2), and plots are only found in the region (R1) that indicates a smaller load compared to the front tires. In contrast, when the vehicle 20 is loaded with a load close to its maximum load capacity, the temperature distribution of the rear tires shows plots in the region close to the baseline (R2), as shown in the upper right of Figure 4. Therefore, a straight line can be defined to define the region (R1) that indicates a smaller load compared to the front tires (in other words, a line separating R1 and R2), and its slope can be used as a threshold. Then, a straight line can be estimated for the temperature distribution of the target rear tire using the least squares method, and if the slope of that line is greater than or equal to the threshold, it can be determined that the vehicle 20 is loaded. In the determination method described with reference to Figure 4, the temperature of the front and rear tires can be determined by using the internal tire temperature, the difference in ambient temperature, or the degree of heat generation. Furthermore, the threshold may be determined using a machine learning method that performs classification, for example, by using historical performance data on the temperature of the front and rear tires of the same type of vehicle 20 as training data.

[0033] The inventors have diligently investigated tire temperature and found that when the vehicle 20 is driven after a short stop, the tire temperature is affected by the environment while stopped (it contains a lot of noise). The influence of the environment while stopped includes heat from the heated road surface, heat from the hot garage, heat from the vehicle body due to driving before stopping, or heat from sunlight, which is transferred to the tire 30. Figures 5 and 7 show examples of changes in the ambient temperature difference between the front and rear wheels of the vehicle 20 after starting to drive. Immediately after starting to drive, the ambient temperature difference between the front wheel and the rear wheel is almost the same (the influence of heat transfer from the environment while stopped is greater than the influence of natural cooling due to driving). For example, even if the temperature of the rear tire is plotted against the temperature of the front tire in a noisy state, accuracy is lost due to the noisy data enclosed by the dashed line, as shown in the left figure of Figure 8, so the relationship between the temperatures of the front and rear wheels cannot be approximated linearly.

[0034] Therefore, the control unit 13 sets the "certain time" as the time until the effects of noise are eliminated by the vehicle 20 running. The certain time is 30 minutes as an example, but is not limited to a specific value and may be determined based on past experimental data regarding the heat transfer of the tire 30. The certain time varies depending on the thermal time constant, for example, so it may be determined according to the size of the tire 30. For example, for large-sized tires 30 such as those for construction vehicles, the certain time may be set to be even longer than for truck tires 30. The control unit 13 also sets the "predetermined time" to a time such that the slope of the ambient temperature difference of the rear wheels of the vehicle 20 with respect to the ambient temperature difference of the front wheels of the vehicle 20 can be calculated using the ambient temperature difference after a certain time has elapsed since the vehicle 20 started running. In other words, the predetermined time is set to a time such that even if the data for the certain time is excluded, prediction using a linear regression equation is possible with the remaining data. The predetermined time is 2 hours as an example, but is not limited to a specific value and may be determined based on past performance data of vehicles 20 equipped with the same type of tire 30. The fixed time and predetermined time are set appropriately in advance and used in the calculation by the calculation unit 132 and the determination by the determination unit 133.

[0035] In the following, the front tires and rear tires may be simply referred to as the front wheels and rear wheels. The determination unit 133 performs a first determination to determine whether the vehicle 20 is loaded or not, based on the degree of heat generation of the rear wheels of the vehicle 20 relative to the degree of heat generation of the front wheels of the vehicle 20. The determination unit 133 also performs a second determination if the input data includes the internal tire temperature and ambient temperature for a period exceeding a predetermined time since the vehicle 20 started driving. In the second determination, the determination of whether the vehicle 20 is loaded or not is made based on the ambient temperature difference between the front wheels and the rear wheels of the vehicle 20.

[0036] The output unit 134 may output the determination result of whether the vehicle 20 is loaded or not, as determined by the determination unit 133, to a terminal device 50 or the like. The output unit 134 may also output numerical values ​​related to the condition of the tires 30 based on the determination result (for example, the cumulative time under full load). At this time, the administrator can plan or execute, for example, replacement, repair, or rotation of the tires 30 based on the displayed information.

[0037] Figure 9 is an example of a flowchart showing the processing of the loading determination method executed by the loading determination device 10 according to this embodiment.

[0038] If the total period of the input data acquired by the acquisition unit 131 exceeds a predetermined time (Yes in step S1), the determination unit 133 determines whether the vehicle 20 is loaded or not by a second determination (step S3). If the total period of the input data acquired by the acquisition unit 131 is less than or equal to the predetermined time (No in step S1), the determination unit 133 determines whether the vehicle 20 is loaded or not by a first determination (step S2). Then, the output unit 134 outputs the determination result of whether the vehicle 20 is loaded or not made by the determination unit 133 (step S4).

[0039] First, the details of the first determination will be explained. Among the input data, the data from a certain period after the start of driving includes the tire temperature, which is affected by the environment while stationary (contains a lot of noise). However, as shown in Figure 5, if the total period of input data is less than a predetermined time, deleting the data from a certain period after the start of driving results in insufficient data, making it impossible to accurately calculate the slope of the ambient temperature difference between the rear wheels of the vehicle 20 and the ambient temperature difference between the front wheels of the vehicle 20. Therefore, the calculation unit 132 uses the input data for the entire period to perform calculation processing to reduce the influence of noise.

[0040] The calculation unit 132 calculates the ambient temperature difference, which is the temperature difference between the temperature inside the tire and the ambient temperature, based on the input data. In the left diagram of Figure 6, the circles indicate the calculated ambient temperature difference. However, as mentioned above, the temperature inside the tire immediately after the start of driving contains a lot of noise, so the calculated ambient temperature difference may be inaccurate. Therefore, the calculation unit 132 calculates the "heat generation rate," which indicates the heat generated during a certain period of driving of the vehicle 20, depending on whether or not there is a load. To calculate the heat generation rate, the calculation unit 132 calculates the natural cooling temperature after a certain period of time based on the cooling coefficient of the tires 30 of the vehicle 20. In the left diagram of Figure 6, the triangles indicate the ambient temperature difference that has decreased due to natural cooling after a certain period of time. The natural cooling temperature may be calculated using a known formula in which the rate of temperature change (dθ / dt) is expressed as the value obtained by multiplying the cooling coefficient by the difference with the ambient temperature (for example, see Japanese Patent Application Publication No. 2021-001625 as a reference). For example, if the cooling coefficient is 0.18, the ambient temperature difference of the tire 30 after 30 minutes will be reduced to approximately 82%. The calculation unit 132 then calculates the degree of heat generation for the front and rear wheels of the vehicle 20 over a certain period of time, based on the calculated natural cooling temperature and the temperature inside the tire after a certain period of time. As shown in the left diagram of Figure 6, the degree of heat generation can be calculated as the difference between the ambient temperature difference reduced by natural cooling (triangle) and the ambient temperature difference calculated based on the input data (circle).

[0041] The determination unit 133 determines whether the vehicle 20 is loaded or unloaded based on the degree of heat generated by the rear wheels of the vehicle 20 relative to the degree of heat generated by the front wheels of the vehicle 20. In other words, the determination unit 133 performs a first determination using the degree of heat generated as the temperature of the front and rear wheels, as explained with reference to Figure 4. In the right diagram of Figure 6, the determination unit 133 generates a dashed line passing through the origin using the least squares method or the like, calculates the slope of that line, and determines whether the vehicle 20 is loaded or unloaded by comparing the calculated slope with a threshold. In the example in the right diagram of Figure 6, since the slope of the dashed line is less than the threshold, it is determined that the vehicle 20 is unloaded.

[0042] In this way, by having the determination unit 133 perform the first determination, the degree of heat generation is calculated using the input data (tire temperature) for the entire period containing noise, thereby reducing the influence of noise and enabling a highly accurate determination of whether or not the vehicle 20 is loaded.

[0043] Next, the second determination will be explained in detail. The determination unit 133 can determine whether or not the vehicle 20 is loaded for any input data by performing only the first determination described above. However, the computational load of calculating the degree of heat generation becomes large, especially when there is a large amount of data. Therefore, as shown in Figure 7, it is preferable that the second determination is performed instead of the first determination when the total period of the input data exceeds a predetermined time.

[0044] The calculation unit 132 calculates only the ambient temperature difference based on the tire temperature and ambient temperature after a certain amount of time has elapsed since the vehicle 20 started driving, based on the input data. In other words, the calculation unit 132 calculates the ambient temperature difference while excluding the tire temperature which contains noise. As described above, even if the temperature of the rear tire is plotted against the temperature of the front tire in a state containing a lot of noise, accuracy is lost due to the data enclosed by the dashed line in the left diagram of Figure 8. By excluding the tire temperature which contains noise (right diagram of Figure 8), the determination unit 133 can accurately determine whether the vehicle 20 is loaded or not based on the ambient temperature difference of the rear tire of the vehicle 20 relative to the ambient temperature difference of the front tire of the vehicle 20. The determination unit 133 performs a second determination using the ambient temperature difference as the temperature of the front tire and rear tire, using the determination method described with reference to Figure 4. In the right-hand diagram of Figure 8, the determination unit 133 generates a dashed line passing through the origin using the least squares method or the like, calculates the slope of that line, and determines whether the vehicle 20 is loaded or not by comparing the calculated slope with a threshold. In the example shown in the right-hand diagram of Figure 8, since the slope of the dashed line is less than the threshold, it is determined that the vehicle 20 is unloaded.

[0045] In this way, by having the determination unit 133 perform a second determination, input data (tire temperature) from periods containing noise can be excluded, reducing the calculation load, while determining with high accuracy whether or not the vehicle 20 is loaded based on the tire temperature.

[0046] As described above, the load determination device 10, program, and load determination method according to this embodiment can reduce or eliminate the influence of the environment while the vehicle 20 is stopped, and can determine with high accuracy whether or not the vehicle 20 is loaded based on the temperature inside the tires.

[0047] While embodiments of this disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art will find it easy to make various modifications or alterations based on this disclosure. Therefore, it should be noted that these modifications or alterations are included within the scope of this disclosure. For example, the functions included in each component or step can be rearranged in a logically consistent manner, and multiple components or steps can be combined into one or separated. Embodiments relating to this disclosure can also be realized as storage media recording programs executed by a processor in the device. These are also understood to be included within the scope of this disclosure. Contribution to the United Nations-led Sustainable Development Goals (SDGs)

[0048] The SDGs have been proposed to realize a sustainable society. One embodiment of this disclosure is considered to be a technology that can contribute to "No. 9 Industry, Innovation and Infrastructure" and other goals. [Explanation of Symbols]

[0049] 10 Loading Determination Device 11 Communications Department 12 Storage section 13 Control Unit 20 vehicles 30 tires 40 Networks 50 Terminal devices 70 Detection device 80 In-vehicle communication device 90 Storage device 131 Acquisition Department 132 Calculation Section 133 Judgment section 134 Output section

Claims

1. An acquisition unit that acquires input data including the internal tire temperature and ambient temperature for the front and rear wheels of the vehicle, respectively, as detected by a detection device mounted on the vehicle, A calculation unit calculates the natural cooling temperature after a certain period of time based on the temperature difference between the temperature inside the tire and the ambient temperature, which is the temperature difference between the ambient temperature and the temperature inside the tire, and the cooling coefficient of the vehicle's tire, and calculates the degree of heat generation for the front and rear wheels of the vehicle during that certain period of time based on the calculated natural cooling temperature and the temperature inside the tire after that certain period of time. A loading determination device comprising: a determination unit that performs a first determination to determine whether or not the vehicle is loaded based on the degree of heat generation of the rear wheels of the vehicle relative to the degree of heat generation of the front wheels of the vehicle.

2. If the input data includes the tire temperature and the outside air temperature for a period exceeding a predetermined time after the vehicle starts driving, The calculation unit calculates only the difference in ambient temperature based on the temperature inside the tire and the ambient temperature after a certain period of time has elapsed since the vehicle started driving. The loading determination device according to claim 1, wherein the determination unit performs a second determination to determine whether or not the vehicle is loaded based on the difference in ambient temperature between the rear wheels of the vehicle and the difference in ambient temperature between the front wheels of the vehicle.

3. The load determination device according to claim 2, wherein the predetermined time is set so that the slope of the difference in ambient temperature at the rear wheels of the vehicle relative to the difference in ambient temperature at the front wheels of the vehicle can be calculated using the difference in ambient temperature after a certain period of time has elapsed since the vehicle started to travel.

4. The load determination device according to any one of claims 1 to 3, wherein the aforementioned certain time is set as the time until the effects of noise are eliminated by the vehicle running.

5. In the load determination device, The system acquires input data, including the internal tire temperature and ambient temperature for the front and rear wheels of the vehicle, as detected by a detection device mounted on the vehicle. Based on the temperature difference between the temperature inside the tire and the ambient temperature, which is the ambient temperature difference, and the cooling coefficient of the vehicle's tires, the natural cooling temperature after a certain period of time is calculated, and based on the calculated natural cooling temperature and the temperature inside the tire after the certain period of time, the degree of heat generation for the front and rear wheels of the vehicle during that certain period of time is calculated. A program that performs a first determination to determine whether or not the vehicle is loaded, based on the degree of heat generated by the rear wheels of the vehicle relative to the degree of heat generated by the front wheels of the vehicle.

6. A loading determination method performed by a loading determination device, The aforementioned load determination device, The system acquires input data, including the internal tire temperature and ambient temperature for the front and rear wheels of the vehicle, as detected by a detection device mounted on the vehicle. Based on the temperature difference between the temperature inside the tire and the ambient temperature, which is the ambient temperature difference, and the cooling coefficient of the vehicle's tires, the natural cooling temperature after a certain period of time is calculated, and based on the calculated natural cooling temperature and the temperature inside the tire after the certain period of time, the degree of heat generation for the front and rear wheels of the vehicle during that certain period of time is calculated. A method for determining whether a vehicle is loaded, comprising: performing a first determination to determine whether a vehicle is loaded or not based on the degree of heat generated by the rear wheels of the vehicle relative to the degree of heat generated by the front wheels of the vehicle.

Images