Information processing apparatus

Abstract

To evaluate the slipperiness of a vehicle on a road in more detail.SOLUTION: The information processing device calculates the actual measurement value of the wheel speed difference of the target vehicle according to the probe information including the wheel speed of each wheel of the target vehicle in the evaluation section of the slipperiness of the vehicle. Further, the information processing apparatus acquires the reference value of the wheel speed difference of the target vehicle in the evaluation interval. The information processing apparatus calculates an evaluation parameter by using the measured value and the reference value. The information processing device evaluates the slipperiness of the vehicle due to the influence of the change in the road surface condition in the evaluation interval according to the evaluation parameter. Then, the information processing apparatus outputs result information of the evaluation.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to an information processing device. [Background technology]

[0002] Patent Document 1 discloses a driving assistance device. The driving assistance device disclosed in Patent Document 1 acquires vehicle speed data before the ABS of the vehicle is activated and vehicle speed data when the ABS of the vehicle is deactivated. The driving assistance device calculates a sliding friction coefficient based on the vehicle speed data before the ABS is activated and the vehicle speed data when the ABS is deactivated. The driving assistance device determines whether the sliding friction coefficient is equal to or less than a threshold value, and if the sliding friction coefficient is equal to or less than the threshold value, detects that a slip due to a frozen road surface has occurred.

[0003] Patent Document 2 discloses a stuck vehicle risk calculation program. The program calculates predicted snow and ice condition data in a road surface snow and ice layer based on a heat balance model and an ice-water-air balance model for the road surface snow and ice layer using predicted data on meteorological and traffic conditions. The program also determines a road surface sliding friction coefficient based on the calculated snow and ice condition prediction data. The program then calculates a risk of a vehicle getting stuck in a road surface snow and ice layer, which is determined by a linear combination of a first function that uses the road surface snow and ice thickness as a variable from the snow and ice condition prediction data, a second function that uses the road surface snow and ice moisture content as a variable from the snow and ice condition prediction data, and a third function that uses the road surface sliding friction coefficient as a variable.

[0004] Patent Document 3 discloses a road surface condition identification device. The road surface condition identification device disclosed in Patent Document 3 calculates the wheel speed of a vehicle. The road surface condition identification device calculates the wheel acceleration / deceleration from the wheel speed. The road surface condition identification device calculates the difference in wheel acceleration / deceleration calculated by wheel acceleration / deceleration calculation means. The road surface condition identification device performs low-pass filtering to pass only the low-frequency components of a value obtained by rectifying the wheel acceleration / deceleration difference. The road surface condition identification device then compares the low-pass filtered value obtained by the low-pass filter means with a road surface condition identification threshold value predetermined based on the vehicle characteristics and road surface condition to identify the road surface condition. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-24312 [Patent Document 2] Japanese Patent Application Publication No. 2023-119792 [Patent Document 3] Japanese Patent Application Publication No. 11-192932 Summary of the Invention [Problem to be solved by the invention]

[0006] The present disclosure aims to provide a more detailed assessment of the slipperiness of a vehicle on a road. [Means for solving the problem]

[0007] An information processing device according to a first aspect of the present disclosure includes: calculating an actual measurement value of a wheel speed difference of the target vehicle in accordance with probe information including the wheel speed of each wheel of the target vehicle in an evaluation section of vehicle slipperiness; acquiring a reference value of the wheel speed difference of the target vehicle in the evaluation section; calculating an evaluation parameter using the actual measurement value and the reference value; Evaluating the slipperiness of a vehicle due to the influence of changes in road surface conditions in the evaluation section according to the evaluation parameters; outputting information on the result of the evaluation; The controller is configured to:

[0008] An information processing device according to a second aspect of the present disclosure includes: receiving probe information in real time, the probe information including the position of the target vehicle acquired by a GPS device mounted on the target vehicle and the wheel speed of each wheel sensed by a wheel speed sensor of the target vehicle; determining in real time whether the target vehicle is traveling in an evaluation section for vehicle slipperiness by referring to the probe information; calculating an actual measurement value of a wheel speed difference of the target vehicle in accordance with the probe information when the target vehicle is traveling in the evaluation section; acquiring a reference value of the wheel speed difference in the evaluation section; calculating an evaluation parameter using the actual measurement value and the reference value; Evaluating the slipperiness of a vehicle due to the influence of changes in road surface conditions in the evaluation section according to the evaluation parameters; outputting the evaluation result information to an external device; The controller is configured to: [Effects of the Invention]

[0009] The present disclosure makes it possible to evaluate the slipperiness of a vehicle on a road in more detail. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of an evaluation system. [Figure 2] FIG. 2 is a block diagram illustrating an example of the functional configuration of the evaluation server. [Figure 3] FIG. 3 is a diagram showing an example of a table configuration of history information held in the history information database. [Figure 4] FIG. 4 is a flowchart of the process executed by the control unit in the assessment server. [Figure 5] FIG. 5 is a diagram showing the difference between the inner and outer wheels when the vehicle is traveling around a curve. DETAILED DESCRIPTION OF THE INVENTION

[0011] When a vehicle is traveling on a road that is prone to slippage, the wheels are more likely to spin. Therefore, it is expected that the wheel speed difference will be large when the vehicle is traveling on a road that is prone to slippage. On the other hand, there are cases where the road is more prone to slippage than usual due to the influence of changes in road surface conditions. Here, changes in road surface conditions occur due to factors other than the road shape or the vehicle's traveling conditions. Therefore, the information processing device according to the first aspect of the present disclosure uses the wheel speed difference to evaluate the vehicle's slipperiness due to the influence of changes in road surface conditions.

[0012] A control unit of an information processing device according to a first aspect of the present disclosure calculates an actual measurement value of a wheel speed difference of a target vehicle in accordance with probe information. Here, the probe information is information including the wheel speeds of each wheel of the target vehicle in an evaluation section for vehicle slipperiness. The control unit of the information processing device also acquires a reference value of the wheel speed difference of the target vehicle in the evaluation section. The control unit of the information processing device calculates an evaluation parameter using the actual measurement value and the reference value. This makes it possible to calculate the wheel speed difference caused by the influence of changes in road surface conditions. Here, the evaluation parameter is a value that correlates with the vehicle's slipperiness due to changes in road surface conditions. Therefore, the control unit of the information processing device evaluates the vehicle's slipperiness due to the influence of changes in road surface conditions in the evaluation section in accordance with the evaluation parameter. Then, the control unit of the information processing device outputs evaluation result information.

[0013] As explained above, the evaluation parameters are calculated by the information processing device. The information processing device evaluates the slipperiness of the vehicle due to the influence of changes in road surface conditions in the evaluation section according to the evaluation parameters. In this way, it is possible to evaluate the slipperiness of the vehicle on the road in more detail.

[0014] Specific embodiments of the present disclosure will be described below with reference to the accompanying drawings. Unless otherwise specified, the hardware configuration, module configuration, functional configuration, etc. described in each embodiment are not intended to limit the technical scope of the disclosure to those configurations.

[0015] <Embodiment> (System Overview) An evaluation system 1 in this embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing a schematic configuration of the evaluation system 1. The evaluation system 1 includes an on-vehicle device 100, an evaluation server 200, and a user terminal 300. In the evaluation system 1, the on-vehicle device 100, the evaluation server 200, and the user terminal 300 are interconnected by a network N1. The network N1 may be, for example, a WAN (Wide Area Network), which is a global public communication network such as the Internet, or a telephone communication network such as a mobile phone.

[0016] (In-vehicle device) The in-vehicle device 100 is a device mounted on the vehicle 10. The in-vehicle device 100 acquires probe information from an electronic control unit (ECU) of the vehicle 10 via an in-vehicle network. Here, the probe information is information including the position of the vehicle 10, the accelerator operation amount in the vehicle 10, the speed of the vehicle 10, and the wheel speed of each wheel of the vehicle 10.

[0017] Here, the position of the vehicle 10 is acquired by a GPS sensor in the vehicle 10. Furthermore, the accelerator operation amount in the vehicle 10 is acquired by a sensor that senses the depression amount of the accelerator pedal in the vehicle 10. Furthermore, the wheel speed of each wheel of the vehicle 10 is acquired by a wheel speed sensor in the vehicle 10 sensing the wheel speed of each wheel. The wheel speed sensor senses the angular velocity of each wheel as the wheel speed. In this embodiment, the vehicle 10 has four wheels. Therefore, the probe information includes information indicating the wheel speeds of the four wheels. Furthermore, the on-vehicle device 100 calculates the speed of the vehicle 10 from the wheel speeds of each wheel of the vehicle 10 sensed by the wheel speed sensor. The on-vehicle device 100 transmits the probe information to the evaluation server 200 in real time via the network N1.

[0018] (evaluation server) The evaluation server 200 is a server device that evaluates the slipperiness (ease of slipping) of a vehicle on a road. The evaluation server 200 receives probe information of the vehicle 10 from the on-board device 100 via the network N1. The evaluation server 200 evaluates the slipperiness of the vehicle in the evaluation section according to the probe information of the vehicle 10 received from the on-board device 100. The evaluation server 200 outputs information indicating the evaluation result of the slipperiness of the vehicle in the evaluation section (hereinafter, sometimes referred to as "evaluation information") to the user terminal 300 via the network N1. The method by which the evaluation server 200 evaluates the slipperiness of the vehicle in the evaluation section according to the probe information will be described in detail later.

[0019] The evaluation server 200 is configured to include a computer having a processor 210, a main memory 220, an auxiliary memory 230, and a communication interface (communication I / F) 240. The processor 210 is, for example, a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). The main memory 220 is, for example, a RAM (Random Access Memory). The auxiliary memory 230 is, for example, a ROM (Read Only Memory). The auxiliary storage unit 230 is, for example, a hard disk drive (HDD) or a disk recording medium such as a CD-ROM, a DVD disk, or a Blu-ray disk. The auxiliary storage unit 230 may also be a removable medium (portable storage medium). Examples of removable media include a USB memory or an SD card. The communication I / F 240 is, for example, a local area network (LAN) interface board or a wireless communication circuit for wireless communication.

[0020] In the assessment server 200, the auxiliary storage unit 230 stores an operating system (OS), various programs, various information tables, etc. Furthermore, in the assessment server 200, the processor 210 loads the programs stored in the auxiliary storage unit 230 into the main storage unit 220 and executes them to realize various functions as described below. However, some or all of the functions of the assessment server 200 may be realized by hardware circuits such as ASIC or FPGA. Note that the assessment server 200 does not necessarily have to be realized by a single physical configuration, and may be composed of multiple computers that cooperate with each other. Note that the in-vehicle device 100 and the user terminal 300 are also composed of computers, just like the assessment server 200.

[0021] (user terminal) The user terminal 300 is a terminal associated with a user who receives the evaluation results of the vehicle's slipperiness. Here, the terminal associated with the user is, for example, a computer or a mobile information terminal used by the user. The terminal associated with the user may also be, for example, an in-vehicle device such as a navigation system installed in the vehicle used by the user. The user terminal 300 receives the evaluation information from the evaluation server 200 via the network N1. This allows the user of the user terminal 300 to understand the vehicle's slipperiness in the evaluation section.

[0022] (Functional configuration) Next, the functional configuration of the assessment server 200 constituting the assessment system 1 will be described with reference to Fig. 2. Fig. 2 is a block diagram showing an example of the functional configuration of the assessment server 200. The assessment server 200 includes a control unit 201, a communication unit 202, and a history information database 203 (history information DB203).

[0023] The control unit 201 has a function of performing arithmetic processing for controlling the assessment server 200. The control unit 201 can be realized by the processor 210 in the assessment server 200. The communication unit 202 has a function of connecting the assessment server 200 to the network N1. The communication unit 202 can be realized by a communication I / F in the assessment server 200. The control unit 201 receives probe information from the in-vehicle device 100 via the communication unit 202. The control unit 201 updates the history information held in the history information DB 203 according to the probe information received from the in-vehicle device 100.

[0024] The history information DB 203 has a function of storing history information. The history information is information that indicates the history of wheel speed differences when the vehicle travels on a road. Here, the wheel speed difference is a value obtained by subtracting the minimum wheel speed from the maximum wheel speed of the vehicle. Note that if the vehicle 10 is a two-wheel drive vehicle and the wheel speeds of the non-drive wheels and the drive wheels are the same, the wheel speed difference may be determined by the absolute value of the difference between the wheel speed of the non-drive wheels and the wheel speed of the drive wheels.

[0025] Fig. 3 is a diagram showing an example of a table configuration of history information stored in the history information DB 203. As shown in Fig. 3, the history information has an in-vehicle device ID field, a section ID field, a shape field, a date and time field, a wheel speed difference field, a speed field, and a weather field.

[0026] The on-board device ID field stores an identifier (on-board device ID) for identifying the on-board device that transmitted the probe information. The section ID field stores an identifier (section ID) for identifying a section of the road. The section ID field stores the section ID of a section that includes an evaluation section of the road for vehicle slipperiness. The shape field stores information indicating the road shape of the section with the corresponding section ID. Specifically, the shape field stores information indicating the curve shape of the section with the corresponding section ID. As information indicating the curve shape, for example, information indicating the curvature (radius of curvature) of the curve is stored. Furthermore, if the section with the corresponding section ID is a straight line, the shape field stores information indicating that the section is a straight line. Furthermore, the shape field stores information indicating the gradient of the section with the corresponding section ID.

[0027] The date and time field stores information indicating the date and time when a vehicle equipped with an on-board device having a corresponding on-board device ID traveled through the section having a corresponding section ID. The wheel speed difference field stores information indicating the wheel speed difference when the vehicle traveled through the section having a corresponding section ID. The control unit 201 calculates the wheel speed difference when the vehicle traveled through the section having a corresponding section ID based on the vehicle's position in the probe information and the wheel speeds of each wheel of the vehicle. That is, when the control unit 201 refers to the probe information and determines that the vehicle is traveling through the section having a corresponding section ID, it calculates the wheel speed difference by subtracting the minimum wheel speed from the maximum wheel speed of the vehicle. The control unit 201 then stores the calculated wheel speed difference in the wheel speed difference field.

[0028] The speed field stores information regarding the speed of the vehicle when traveling through the section with the corresponding section ID. Specifically, the speed field stores information indicating whether the speed of the vehicle when traveling through the section with the corresponding section ID was constant. The control unit 201 references the vehicle speed in the probe information and determines whether the speed of the vehicle when traveling through the section with the corresponding section ID was constant. The control unit 201 then stores the determination result in the speed field. Here, if the vehicle speed is constant, the speed field stores information indicating "constant speed." Furthermore, if the vehicle speed is not constant, the speed field stores information indicating "speed change."

[0029] In addition, the speed field stores information indicating the speed when the vehicle travels through the section of the corresponding section ID. If the speed when the vehicle travels through the section of the corresponding section ID is constant, information indicating the constant speed is stored. If the speed when the vehicle travels through the section of the corresponding section ID changes, information indicating the range of the changed speed is stored.

[0030] The weather field stores information indicating the weather at the date and time when the vehicle traveled through the section with the corresponding section ID. The weather field stores information such as the amount of precipitation, the amount of snow, the temperature, and whether or not the road is frozen. The control unit 201 obtains the weather at the date and time when the vehicle traveled through the section with the corresponding section ID via the communication unit 202 from a server device or the like that manages weather information, and stores the information in the weather field.

[0031] The control unit 201 determines in real time whether the vehicle 10 is traveling in the evaluation section by referring to the probe information received from the in-vehicle device 100. When the vehicle 10 is traveling in the evaluation section, the control unit 201 evaluates the slipperiness of the vehicle in the evaluation section according to the probe information of the vehicle 10.

[0032] At this time, if the vehicle is traveling on a road that is prone to slippage, the wheels are more likely to spin. Therefore, if the vehicle is traveling on a road that is prone to slippage, it is expected that the wheel speed difference will be large. In addition, there are cases where the road is more prone to slippage than usual due to changes in road surface conditions due to precipitation, snow accumulation, or freezing on the road. Therefore, the control unit 201 uses the wheel speed difference to evaluate the vehicle's slipperiness due to the influence of changes in road surface conditions.

[0033] Specifically, the control unit 201 refers to the history information stored in the history information DB 203 and acquires, as a reference value, the wheel speed difference when the vehicle 10 traveled through the evaluation section at a reference date and time. Here, the control unit 201 specifies, as the reference date and time, a date and time when the amount of precipitation is 0, the amount of snowfall is 0, and the road is not frozen. Note that whether the road is frozen may be determined based on whether the air temperature is equal to or higher than a predetermined temperature. Here, the predetermined temperature is set in advance as a temperature at which the road is expected to freeze.

[0034] Furthermore, if there are multiple dates and times that correspond to the reference date and time, the control unit 201 may obtain, as the reference value, the average value of the wheel speed differences at the multiple reference dates and times. Furthermore, even when traveling in the same evaluation section, it is expected that the wheel speed difference will be different when the vehicle 10 is traveling at a high speed and when the vehicle 10 is traveling at a low speed. Therefore, the control unit 201 refers to the speed field in the history information and obtains, as the reference value, the wheel speed difference when the vehicle 10 is traveling at the same speed as the current speed of the vehicle 10 or within a predetermined range from the current speed.

[0035] The control unit 201 calculates the wheel speed difference (the value obtained by subtracting the smallest wheel speed from the largest wheel speed) as an actual measurement value from the wheel speeds of each wheel in the probe information of the vehicle 10. Here, the value obtained by subtracting the reference value from the actual measurement value is the difference between the wheel speed difference when the vehicle 10 is traveling in the evaluation section and the wheel speed difference when the vehicle 10 is traveling in the evaluation section at the reference date and time (the wheel speed difference under normal conditions when no freezing or the like occurs). Therefore, the value obtained by subtracting the reference value from the actual measurement value is the wheel speed difference caused by the influence of changes in road surface conditions. Therefore, the control unit 201 calculates the value obtained by subtracting the reference value from the actual measurement value as an evaluation parameter. Here, the evaluation parameter is a value that correlates with the vehicle's slipperiness due to the influence of changes in road surface conditions. Note that methods other than subtracting the reference value from the actual measurement value can also be used as a method of calculating the evaluation parameter.

[0036] The control unit 201 evaluates the vehicle's slipperiness in the evaluation section according to the calculated evaluation parameters. Here, an evaluation value for vehicle slipperiness associated with each evaluation parameter is set. The control unit 201 determines the evaluation value associated with the calculated evaluation parameter as the evaluation result. Then, the control unit 201 outputs evaluation information including the evaluation value to the user terminal 300 via the communication unit 202. The evaluation information may also include an evaluation value for vehicle slipperiness according to an actual measurement value (an evaluation value for vehicle slipperiness that includes the influence of changes in road surface conditions).

[0037] In this embodiment, multiple vehicles 10 are targets for collecting probe information. In this case, after one vehicle 10 has traveled through the evaluation section, another vehicle 10 may travel through the evaluation section. In this case, the control unit 201 updates the evaluation value to the evaluation value when the other vehicle 10 traveled through the evaluation section. After a predetermined time has elapsed since one vehicle 10 traveled through the evaluation section, the control unit 201 may calculate an evaluation value according to the probe information of the other vehicle 10 that traveled through the evaluation section. Then, the control unit 201 outputs evaluation information including the updated evaluation value to the user terminal 300.

[0038] (flowchart) Next, the process executed by the control unit 201 in the assessment server 200 in the assessment system 1 will be described with reference to Fig. 4. Fig. 4 is a flowchart of the process executed by the control unit 201 in the assessment server 200. This process is a process for outputting assessment information. The process shown in Fig. 5 is repeatedly executed at predetermined intervals.

[0039] In the process shown in FIG. 4, first, in S101, the profile received from the in-vehicle device 100 is Then, in S102, it is determined whether the vehicle 10 is traveling in the evaluation section. If a negative determination is made in S102, the vehicle 10 is not traveling in the evaluation section, and therefore the vehicle's slipperiness in the evaluation section cannot be evaluated. Therefore, the processing shown in FIG. 4 is temporarily terminated.

[0040] If a positive determination is made in S102, the vehicle 10 is traveling through the evaluation section, and therefore an actual measurement value is calculated in S103. That is, the control unit 201 calculates a wheel speed difference in accordance with the wheel speeds of each wheel of the vehicle 10 in the probe information. Furthermore, in S104, the historical information stored in the historical information DB 203 is referenced, and the wheel speed difference when the vehicle 10 traveled through the evaluation section on a reference date and time is acquired as a reference value. Here, the control unit 201 may calculate the reference value each time by referring to the historical information, or may acquire a reference value that has been calculated in advance by referring to the historical information and is stored in the database.

[0041] Next, in S105, an evaluation parameter is calculated according to the actual measurement value and the reference value. That is, the evaluation parameter is output by subtracting the wheel speed difference of the reference value from the wheel speed difference of the actual measurement value. Next, in S106, evaluation information is generated according to the evaluation parameter. Next, in S107, the evaluation information is output to the user terminal 300. Then, the processing shown in FIG. 4 is temporarily terminated.

[0042] As explained above, the evaluation system 1 calculates the evaluation parameters. Then, the information processing device evaluates the vehicle's slipperiness in the evaluation section according to the evaluation parameters. This makes it possible to evaluate the vehicle's slipperiness due to the influence of changes in road surface conditions. In this way, it becomes possible to evaluate the vehicle's slipperiness on the road in more detail.

[0043] (Variation 1) In this embodiment, the reference value is the wheel speed difference when the vehicle 10 travels through the evaluation section on the reference date and time. However, other values ​​can be used as the reference value. In this modified example, the reference value is a value calculated according to a prediction formula for the wheel speed difference caused by the curve shape.

[0044] The control unit 201 acquires the curve shape in the evaluation section. In this embodiment, the control unit 201 acquires the curvature (curvature radius) of the curve as the curve shape in the evaluation section. The control unit 201 references the shape field in the history information held in the history information DB 203 and acquires information indicating the curve shape in the evaluation section. Note that the control unit 201 may acquire the curve shape in the evaluation section from an external server via the communication unit 202.

[0045] FIG. 5 is a diagram showing the wheel difference between the inside and outside when the vehicle 10 is traveling around a curve. In the example shown in FIG. 5, a diagram is shown in which the vehicle 10 is traveling around a left curve. The positions (centers of the contact patches) of the four wheels of the vehicle 10 are defined as points A, B, C, and D, respectively. Here, points A, B, C, and D are located at the positions of the right front wheel, left front wheel, left rear wheel, and right rear wheel of the vehicle 10, respectively. The center (centre) of the vehicle 10 is defined as point X. The wheelbase of the vehicle 10 is defined as HB, and the tread of the vehicle 10 is defined as TR. The center of curvature of the curve is defined as point O.

[0046] When the vehicle 10 is traveling around a left curve, the wheel speed of the wheel located at point A, which is the farthest from point O, is the highest. In this case, the wheel speed of the wheel located at point C, which is the closest from point O, is the lowest. Using Pythagoras' theorem, the distances OA and OC can be expressed by the following (Equation 1) and (Equation 2), respectively.

number

number

[0047] Also, let r be the radius of the wheel, and v be the speed of vehicle 10 (the speed at point X). In this case, the time it takes for vehicle 10 to go around a circle of radius OX is 2πOX / v. On the other hand, when vehicle 10 goes around a circle of radius OX, the wheel at point A moves 2πOA, so the speed of the wheel at point A is (OA / OX)·v, obtained by dividing 2πOA by 2πOX / v. Therefore, the number of rotations of the wheel at point A is (OA / OX)·v / 2πr, obtained by dividing (OA / OX)·v by the circumference of the wheel, 2πr. Therefore, the wheel speed (angular velocity) at point A is (OA / OX)·v / r. Similarly, the wheel speed of the wheel at point C is (OC / OX)·v / r.

[0048] Therefore, the difference (wheel speed difference) between the wheel speed of the wheel at point A and the wheel speed of the wheel at point C is {(OA-OC) / OX}·v / r. Therefore, when the vehicle 10 is traveling on the left curve shown in Fig. 5, the wheel speed difference is expressed by the following (Equation 3) using OX, HB, TR, v, and r.

number

[0049] Here, OX is the radius of curvature of the left curve. HB, TR, and r are values ​​specific to the vehicle 10. v can be acquired from probe information. Therefore, the control unit 201 acquires the curvature (OX) of the curve and the wheelbase (HB), tread (TR), speed (v), and wheel radius (r) of the vehicle 10, and substitutes them into (Equation 3), thereby enabling the control unit 201 to calculate the wheel speed difference predicted to occur when the vehicle 10 is traveling around a left curve.

[0050] Also, when the vehicle 10 is traveling on a right curve, the wheel speed of the wheel located at point B, which is the farthest from point O (the center of curvature of the right curve), is greater than the other wheels. In this case, the wheel speed of the wheel located at point D, which is the closest from point O, is the smallest. There is symmetry between when the vehicle 10 is traveling on a left curve and when it is traveling on a right curve. Therefore, OB when traveling on a right curve is the same value as the right side of (Equation 3). Also, OD when traveling on a right curve is the same value as the right side of (Equation 4). Also, since OX is the radius of curvature of the right curve, when the vehicle 10 is traveling on a right curve, according to (Equation 3), It is possible to calculate the wheel speed difference that is predicted to occur when the vehicle is in a rolling position.

[0051] The control unit 201 calculates the evaluation parameters using the wheel speed difference predicted to occur when the vehicle 10 is traveling around a curve as a reference value. This allows the control unit 201 to calculate the wheel speed difference excluding the wheel speed difference caused by the curve shape. Therefore, the control unit 201 can evaluate the vehicle's slipperiness due to the influence of changes in road surface conditions, excluding the influence of the road shape (curve shape). This also makes it possible to evaluate the vehicle's slipperiness on the road in more detail.

[0052] (Variation 2) When a large torque is applied to the wheel, the rotational force applied to the wheel is larger than when a small torque is applied to the wheel, and therefore, when a large torque is applied to the wheel, the wheel speed difference is more likely to be larger than when a small torque is applied to the wheel.

[0053] Furthermore, when the gradient in the evaluation section is large, the normal force acting on each wheel of the vehicle 10 is smaller than when the gradient is small. As a result, the frictional force acting on the vehicle 10 is smaller. Therefore, when the gradient in the evaluation section is large, the wheel speed difference that occurs due to the generation of torque is more likely to be large than when the gradient is small.

[0054] Therefore, the control unit 201 calculates an evaluation parameter according to the wheel speed difference (estimated wheel speed difference) that is expected to occur when torque is applied to the wheels, and the gradient in the evaluation section. Specifically, the control unit 201 acquires the accelerator operation amount or brake operation amount of the vehicle 10 from the probe information. The control unit 201 acquires a correspondence (hereinafter, sometimes simply referred to as "correspondence") between the gradient, the accelerator operation amount or the brake operation amount, and the estimated wheel speed difference. The control unit 201 acquires a reference value according to the correspondence. Then, the control unit 201 calculates the evaluation parameter according to the acquired reference value.

[0055] Here, the control unit 201 determines the association based on the probe information received in the past. In doing so, the control unit 201 determines the association based on the accelerator operation amount, the brake operation amount, and the wheel speed difference data when traveling through sections with each gradient at a reference date and time. The association may also be determined in advance based on correlations obtained through experiments. In this case, the association is determined based on the results of experiments when the amount of precipitation is 0, the amount of snowfall is 0, and the road is dry.

[0056] This makes it possible to evaluate the vehicle's slipperiness due to changes in road surface conditions, excluding the influence of the vehicle's running state (accelerator operation amount or brake operation amount). This also makes it possible to evaluate the vehicle's slipperiness on the road in more detail.

[0057] Furthermore, when torque is applied to the wheels of the vehicle 10, it is assumed that longitudinal acceleration occurs in the vehicle 10. Therefore, the control unit 201 may acquire the longitudinal acceleration acting on the vehicle 10 from the probe information, instead of the accelerator operation amount or the brake operation amount. Then, the control unit 201 acquires the reference value according to the correspondence between the gradient, longitudinal acceleration, and predicted wheel speed difference that is stored in advance. This also makes it possible to evaluate the vehicle's slipperiness on the road in more detail.

[0058] There are cases where the vehicle 10 travels through an evaluation section that has a gradient and a curved shape while changing the accelerator operation amount, etc. In this case, the control unit 201 may calculate the evaluation parameter by using as a new reference value the sum of a reference value according to the gradient of the evaluation section and the torque of the vehicle 10, and a reference value according to the curved shape of the evaluation section. The vehicle's slipperiness due to the influence of changes in road surface conditions can be evaluated, excluding wheel speed differences caused by applying torque to the wheels when traveling through an evaluation section that has a gradient and a curved shape.

[0059] (Variation 3) A wheel speed difference may occur due to a change in the diameter of the wheels of the vehicle 10. For example, the diameter of one wheel may be smaller than the diameter of the other wheels. In this case, the wheel with the smaller diameter has a higher wheel speed than the other wheels, resulting in a wheel speed difference.

[0060] Here, the diameter of the wheels of the vehicle 10 changes depending on the load on the vehicle 10. Furthermore, if the position of the load on the vehicle 10 is uneven, a load is applied to a specific wheel. This causes the tire on the specific wheel to be crushed, thereby reducing the diameter of the wheel of the vehicle 10. Furthermore, the diameter of the wheels of the vehicle 10 decreases depending on the air pressure of the tires on the wheels. Furthermore, the diameter of the wheels of the vehicle 10 decreases as the tires on the wheels wear.

[0061] Furthermore, when the vehicle 10 is traveling straight, as described above, no wheel speed difference due to a curve occurs. Furthermore, when the vehicle 10 is traveling at a constant speed, as described above, no wheel speed difference due to torque occurs. Therefore, the wheel speed difference when the vehicle 10 is traveling straight and at a constant speed is assumed to be a wheel speed difference caused by a change in the diameter of the wheels of the vehicle 10. Therefore, the control unit 201 refers to the history information stored in the history information DB 203 and acquires, as a reference value, the wheel speed difference when the vehicle 10 is traveling straight and at a constant speed. Specifically, the control unit 201 refers to the shape field and the speed field in the history information and acquires the wheel speed difference when the vehicle 10 traveled through a section ID in which the road shape is straight and information indicating "constant speed" is stored.

[0062] In this case, the history information may contain multiple pieces of data on travel through a section with a section ID where the road shape is straight and information on "constant speed" is stored. In this case, the control unit 201 acquires the wheel speed difference during the most recent travel as the reference value. This makes it possible to acquire the wheel speed difference when traveling with wheels having a diameter closest to the current diameter of the vehicle 10 as the reference value.

[0063] Here, the faster the speed of the vehicle 10, the greater the wheel speed. Therefore, when the speed of the vehicle 10 is high, it is expected that the wheel speed difference between the wheels with smaller diameters and the other wheels will be greater than when the speed of the vehicle 10 is low. Therefore, the control unit 201 acquires, as a reference value, the wheel speed difference when the vehicle 10 is traveling straight at the same speed (constant speed) as the speed when the vehicle 10 is traveling in the evaluation section or at a speed within a predetermined range from that speed.

[0064] The control unit 201 calculates the evaluation parameter by subtracting the reference value from the actual measurement value, thereby making it possible to evaluate the vehicle's slipperiness in the evaluation section while excluding the influence of wheel speed differences caused by changes in the diameter of the wheels of the vehicle 10.

[0065] Note that the diameter of the wheels of the vehicle 10 may be different from when the vehicle 10 traveled through the evaluation section in the past. Therefore, the control unit 201 may calculate the evaluation parameter by using as a new reference value the sum of the reference value when the vehicle 10 traveled through the evaluation section on the reference date and time and the reference value when the vehicle 10 is traveling straight at the same speed (constant speed) as when it is traveling through the evaluation section. This makes it possible to evaluate the vehicle's slipperiness in the evaluation section by further excluding the influence of the wheel diameter of the vehicle 10 being different from when the vehicle 10 traveled through the evaluation section in the past.

[0066] Furthermore, there may be cases where the vehicle 10 travels through an evaluation section having a curved shape with wheels of different diameters. In this case, the control unit 201 may calculate the evaluation parameter by using as a new reference value the sum of a reference value calculated according to a prediction formula for the wheel speed difference caused by the curved shape and a reference value when the vehicle 10 travels straight at the same speed (constant speed) as the speed when traveling through the evaluation section. This makes it possible to evaluate the vehicle's slipperiness in the evaluation section, excluding the influence of the vehicle 10 traveling through an evaluation section having a curved shape with wheels of different diameters.

[0067] Furthermore, there may be cases where the vehicle 10 travels through an evaluation section having a gradient with wheels of different diameters. In this case, the control unit 201 may calculate the evaluation parameters by using as a new reference value the sum of a reference value according to the gradient of the evaluation section and the torque of the vehicle 10, and a reference value when the vehicle 10 is traveling straight at the same speed (constant speed) as the speed when the vehicle 10 is traveling through the evaluation section. This makes it possible to evaluate the vehicle's slipperiness in the evaluation section, excluding the influence of the vehicle 10 traveling through an evaluation section having a gradient with torque being applied to wheels of different diameters of the vehicle 10.

[0068] (Variation 4) In this embodiment, the output destination of the result information is the user terminal 300. However, the output destination of the result information does not necessarily have to be the user terminal 300. The output destination of the result information may be a terminal used by a road administrator. Furthermore, the output destination of the result information may be, for example, a server device that distributes the evaluation results of the vehicle's slipperiness to users.

[0069] <Other embodiments> The above-described embodiment is merely an example, and the present disclosure may be modified as appropriate within the scope of the present disclosure. Furthermore, the processes and means described in the present disclosure may be freely combined and implemented as long as no technical contradiction occurs.

[0070] Furthermore, a process described as being performed by one device may be shared and executed by multiple devices. Alternatively, a process described as being performed by different devices may be executed by a single device. In a computer system, the hardware configuration (server configuration) by which each function is realized can be flexibly changed.

[0071] The present disclosure can also be realized by supplying a computer program implementing the functions described in the above embodiments to a computer, and having one or more processors in the computer read and execute the program. Such a computer program may be provided to the computer via a non-transitory computer-readable storage medium connectable to the computer's system bus or via a network. Non-transitory computer-readable storage media include any type of medium suitable for storing electronic instructions, such as a magnetic disk (e.g., a floppy disk or a hard disk drive (HDD)), an optical disk (e.g., a CD-ROM, a DVD disk, or a Blu-ray disk), a read-only memory (ROM), a random-access memory (RAM), an EPROM, an EEPROM, a magnetic card, a flash memory, or an optical card. [Explanation of symbols]

[0072] 1. Rating System 10. Vehicle 100...In-vehicle equipment 200··Review Server 201 Control section 202··Communications Department 203··History Information DB 300 User terminal

Claims

1. receiving probe information in real time, the probe information including the position of the target vehicle acquired by a GPS device mounted on the target vehicle and the wheel speed of each wheel sensed by a wheel speed sensor of the target vehicle; determining in real time whether the target vehicle is traveling in an evaluation section for vehicle slipperiness by referring to the probe information; calculating an actual measurement value of a wheel speed difference of the target vehicle in accordance with the probe information when the target vehicle is traveling in the evaluation section; acquiring a reference value of the wheel speed difference in the evaluation section; calculating an evaluation parameter using the actual measurement value and the reference value; Evaluating the slipperiness of a vehicle due to the influence of changes in road surface conditions in the evaluation section according to the evaluation parameters; outputting the evaluation result information to an external device; a control unit configured to perform Information processing device.

2. calculating an actual measurement value of a wheel speed difference of the target vehicle in accordance with probe information including the wheel speed of each wheel of the target vehicle in an evaluation section of vehicle slipperiness; acquiring a reference value of the wheel speed difference of the target vehicle in the evaluation section; calculating an evaluation parameter using the actual measurement value and the reference value; Evaluating the slipperiness of a vehicle due to the influence of changes in road surface conditions in the evaluation section according to the evaluation parameters; outputting information on the result of the evaluation; a control unit configured to perform Information processing device.

3. acquiring the reference value includes acquiring a wheel speed difference when the target vehicle travels through the evaluation section at a reference time. The information processing device according to claim 2 .

4. Obtaining the reference value acquiring a curve shape in the evaluation section; calculating the reference value according to a prediction formula for a wheel speed difference caused by the curve shape; Including, The information processing device according to claim 2 .

5. the probe information includes at least one of an accelerator operation amount, a brake operation amount, and a longitudinal acceleration of the target vehicle in the evaluation section; acquiring the reference value includes acquiring at least one of an accelerator operation amount, a brake operation amount, and a longitudinal acceleration of the target vehicle, and a predicted value of a wheel speed difference that occurs depending on a gradient in the evaluation section; 5. The information processing device according to claim 2 or 4.

6. acquiring the reference value includes acquiring a wheel speed difference when the target vehicle is traveling straight and at a constant speed. The information processing device according to claim 2 .

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