Determination device, information transmission device, and determination system

Abstract

The invention provides a determination apparatus, an information transmission apparatus, and a determination system. A determination device acquires variation data indicating the transition of a variation value, which is the difference between a pre-processing wheel speed detected by a wheel speed sensor that detects the rotational speed of a wheel provided in a vehicle and a post-processing wheel speed obtained by applying a low-pass filtering process to the pre-processing wheel speed. The determination device determines the presence or absence of an abnormality in the wheel on the basis of the fluctuation data.

Description

Technical Field

[0001] The present disclosure relates to a determination device, an information sending device, and a determination system. Background Art

[0002] Japanese Patent No. 6526818 describes a determination device that uses the rotational speed of a wheel to determine an abnormality in the wheel. Summary of the Invention

[0003] Problems to be solved by the invention

[0004] Abnormalities in the wheels can affect the running of the vehicle. Currently, it is desired to be able to detect abnormalities in the wheels before they have a significant impact on the running of the vehicle.

[0005] Methods for solving problems

[0006] A determination device according to one embodiment of the present disclosure is configured to obtain change data indicating a shift in a change value, wherein the change value is a difference between a pre-processing wheel speed detected by a wheel speed sensor that detects a rotational speed of a wheel of a vehicle and a post-processing wheel speed obtained by applying a low-pass filter to the pre-processing wheel speed, and to determine the presence or absence of an abnormality in the wheel based on the change data.

[0007] An information sending device according to one embodiment of the present disclosure is configured to obtain a pre-processing wheel speed detected by a wheel speed sensor that detects the rotational speed of a wheel of a vehicle, obtain a post-processing wheel speed by applying a low-pass filter to the pre-processing wheel speed, calculate a variation value that is the difference between the pre-processing wheel speed and the post-processing wheel speed, and send variation data indicating the transition of the variation value to a determination device.

[0008] A determination system according to one embodiment of the present disclosure includes an information transmission device and a determination device. The information transmission device is configured to obtain a pre-processed wheel speed detected by a wheel speed sensor that detects the rotational speed of a wheel of a vehicle, obtain a post-processed wheel speed by applying a low-pass filter to the pre-processed wheel speed, calculate a variation value representing the difference between the pre-processed wheel speed and the post-processed wheel speed, and transmit variation data indicating the transition of the variation value to the determination device. The determination device is configured to determine the presence of an abnormality in the wheel based on the variation data, and, if it is determined that the wheel has an abnormality, notify a user of the vehicle of information indicating the presence of the abnormality in the wheel. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram showing the structure of a determination system according to one embodiment.

[0010] Figure 2 To express Figure 1 A sequence diagram of the communication method in the determination system.

[0011] Figure 3 This is a graph showing an example of the change in wheel speed before the treatment when there is no looseness in the connection between the wheel and the hub.

[0012] Figure 4 This is a graph showing an example of the change in wheel speed before processing when there is looseness in the connection between the wheel and the hub.

[0013] Figure 5 This is a graph showing an example of the change in wheel speed before processing when the vehicle travels on a road with large unevenness.

[0014] Figure 6 This is a graph showing an example of changes in the wheel speed before processing and the wheel speed after processing.

[0015] Figure 7 This is a graph showing an example of the transition of the amount of change when there is no looseness in the connection between the wheel and the hub.

[0016] Figure 8 This is a graph showing an example of the transition of the amount of change when there is looseness in the connection between the wheel and the hub.

[0017] Figure 9 This is a graph showing an example of the transition when an upper limit value is set for the amount of change when there is no looseness in the connection between the wheel and the hub.

[0018] Figure 10 This is a graph showing an example of the transition when an upper limit value is set for the amount of change when there is looseness in the connection between the wheel and the hub.

[0019] Figure 11 This is a graph showing an example of the transition of the cumulative time-integrated value of the fluctuation amount in a predetermined period.

[0020] Figure 12 It is a sequence diagram showing a communication method in the determination system of the first modification example.

[0021] Figure 13 This is a graph showing an example of the transition of the cumulative time-integrated value before and after the loosening of the connection between the wheel and the hub occurs.

[0022] Figure 14This is a table showing the form of past slopes stored for determining threshold values ​​in the determination system of the second modified example.

[0023] Figure 15 This is a graph showing an example of transition of the accumulation of time-integrated values ​​for each of a wheel with no looseness in connection with the hub and a wheel with looseness, for a plurality of wheels included in a vehicle.

[0024] Figure 16 This is a graph showing an example of the transition of the amount of change when there is no looseness in the connection between the wheel and the hub, and the relationship between the predetermined range.

[0025] Figure 17 This is a graph showing an example of the transition of the amount of change when there is looseness in the connection between the wheel and the hub, and the relationship between the change and the predetermined range.

[0026] Figure 18 It is a sequence diagram showing a communication method in the determination system according to the fourth modification example.

[0027] Figure 19 This is a graph showing the transition of the number of convergences in the determination system of the fifth modification example.

[0028] Figure 20 This is a table showing the form of the past convergence counts stored for determining the threshold value in the determination system of the fifth modification example.

[0029] Figure 21 This is a graph showing an example of transition of the number of convergences for each of a wheel with no looseness in connection with the hub and a wheel with looseness, for a plurality of wheels included in a vehicle. DETAILED DESCRIPTION

[0030] Hereinafter, an embodiment of the determination system will be described with reference to Figures 1 to 11 To explain.

[0031] <Structure of Determination System 100>

[0032] like Figure 1 As shown, the determination system 100 includes an information transmission device 28 provided in the vehicle 10 and a determination device 21. The determination device 21 is, for example, a server provided outside the vehicle 10. The determination device 21 may also be mounted on the vehicle 10.

[0033] Vehicle 10 includes four wheels: FR wheel 17, FL wheel 18, RR wheel 19, and RL wheel 20, and information transmission device 28. FR wheel 17 is located on the front right side of vehicle 10. FL wheel 18 is located on the front left side of vehicle 10. RR wheel 19 is located on the rear right side of vehicle 10. RL wheel 20 is located on the rear left side of vehicle 10.

[0034] like Figure 1 As shown, each wheel of vehicle 10 is coupled to a corresponding hub. FR wheel 17 is coupled to FR hub 24. FL wheel 18 is coupled to FL hub 25. RR wheel 19 is coupled to RR hub 26. RL wheel 20 is coupled to RL hub 27.

[0035] like Figure 1 As shown, the information transmitting device 28 includes a plurality of electronic control units (ECUs) and a plurality of wheel speed sensors 15. The information transmitting device 28 includes a brake ECU 11 and a central ECU 12 as the electronic control units.

[0036] like Figure 1 As shown, the central ECU 12 includes a storage device 14 storing programs and a processing circuit 13 that executes various processes by executing the programs stored in the storage device 14. The processing circuit 13 includes a processor. The central ECU 12 and the brake ECU 11 are connected to each other so as to be able to communicate with each other.

[0037] like Figure 1 As shown, four wheel speed sensors 15 are provided on the vehicle 10 so as to correspond to each of the FR wheel 17, the FL wheel 18, the RR wheel 19, and the RL wheel 20. Figure 1 As shown, each wheel speed sensor 15 is directly connected to the brake ECU 11 via a communication line 16 .

[0038] Each wheel speed sensor 15 detects the rotational speed of its corresponding wheel. Each wheel speed sensor 15 transmits the detected rotational speed as the pre-processing wheel speed to the brake ECU 11 via the communication line 16. In this way, the brake ECU 11 obtains the pre-processing wheel speed detected by the wheel speed sensor 15.

[0039] like Figure 1 As shown, the determination device 21 includes a storage device 23 storing a program, and a processing circuit 22 that executes various processes by executing the program stored in the storage device 23. The processing circuit 22 includes a processor.

[0040] Each of the processing circuits 13 and 22 may also include one or more dedicated hardware circuits, such as application-specific integrated circuits (ASICs), that perform at least a portion of the various processes. Alternatively, each of the processing circuits 13 and 22 may include a combination of one or more processors and one or more dedicated hardware circuits. The processor may include a CPU and memory such as RAM and ROM. The memory may store program code or instructions configured to cause the CPU to execute the processes. Memory, i.e., computer-readable media, includes all available media that can be accessed by a general-purpose or special-purpose computer.

[0041] The determination device 21 and the information transmission device 28 are connected to each other so as to be able to communicate with each other. The determination device 21 can be connected to the information transmission device 28 by wire or wirelessly, for example. The determination device 21 and the central ECU 12 are connected to each other so as to be able to communicate with each other.

[0042] The determination device 21 determines whether there is an abnormality in one or more wheels of the vehicle 10 based on information received from the information transmitting device 28. As an abnormality in a wheel, the determination device 21 determines whether there is looseness in the connection between the wheel and the hub.

[0043] Figure 2 FIG. 2 shows a method of communication performed between the brake ECU 11, the central ECU 12, the wheel speed sensor 15 and the determination device 21. Figure 2 In the example, the processing performed by the central ECU 12 is performed by the processing circuit 13. Figure 2 In the example, the processing performed by the determination device 21 is performed by the processing circuit 22.

[0044] Below, for Figure 2 The sequence diagram is shown in Figures 3 to 11 .

[0045] <Overview of Processing Front Wheel Speed>

[0046] like Figure 2 As shown in the upper part of FIG, the wheel speed sensor 15 sends the wheel speed before processing to the brake ECU 11. Figures 3 to 5 At the same time, the characteristics of processing the front wheel speed are explained.

[0047] Figure 3 An example of the change in wheel speed before the process is shown when there is no looseness in the connection between the wheel and the hub. Figure 3 The graph shown shows, for example, the wheel speed of the FR wheel 17 before processing detected by the wheel speed sensor 15 .

[0048] exist Figure 3 In the graph, the vertical axis represents the wheel speed before treatment. Figure 3 In the graph, the horizontal axis represents time. Figure 4 as well as Figure 5 The same is true for .

[0049] The wheel speed before the treatment will be affected by the slight unevenness of the road surface and the tread pattern of the wheel and will change slightly. Figure 3 The wheel speed before the treatment shown varies slightly with the passage of time.

[0050] Figure 4 An example of the change in wheel speed before processing when there is looseness in the connection between the wheel and the hub is shown. Figure 4 The graph shown shows the wheel speed before processing of the FR wheel 17 detected by the wheel speed sensor 15 when the bolts connecting the FR wheel 17 and the FR hub 24 are loosened by one rotation, for example. Figure 4 The wheel speed before treatment shown is the same as that detected except that the bolt is loose. Figure 3 The wheel speed is detected under the same conditions as before the processing shown. Figure 4 The wheel speed before processing is shown as follows: Figure 3 The wheel speeds before processing shown are wheel speeds before processing detected at the same location.

[0051] If Figure 3 and Figure 4 For comparison, Figure 4 The amplitude of the graph is Figure 3 That is, the amount of change in the wheel speed before treatment when there is looseness in the connection between the wheel and the hub is greater than the amount of change in the wheel speed before treatment when there is no looseness.

[0052] Figure 5 The diagram shows that the vehicle 10 travels through the vehicle 10 without loosening the connection between the wheel and the hub. Figure 3 This is an example of the change in wheel speed before processing on a road with larger unevenness than the situation. Figure 5 The graph shown is, for example, a graph showing the time period between when the vehicle 10 passes by and when the vehicle 10 is detected. Figure 3 The wheel speed before processing is the wheel speed of the FR wheel 17 detected by the wheel speed sensor 15 in the case of a road surface with a large unevenness compared to the road surface shown. Figure 5 The wheel speed before treatment is shown in the figure, except that the road surface is relatively uneven. Figure 3The wheel speed is detected under the same conditions as before the processing shown. Figure 5 The wheel speed before processing shown is the vehicle 10 with the detected Figure 3 The wheel speed before processing shown is the wheel speed before processing detected when the vehicle travels at the same speed.

[0053] exist Figure 5 The part surrounded by the dotted line reflects the Figure 3 On the other hand, the front wheel speed is Figure 5 At the portion not surrounded by the dotted line, the vehicle 10 is in contact with Figure 3 The vehicle is driven on a road surface with roughly the same size of bumps and depressions as the road surface it has driven on.

[0054] like Figure 5 As shown, the amplitude of the curve in the part not surrounded by the dotted line is Figure 3 The amplitudes of the graphs are roughly the same size. On the other hand, Figure 5 The amplitude of the curve in the part surrounded by the dotted line is Figure 3 That is, even if there is no looseness in the connection between the wheel and the hub, the greater the unevenness of the road surface, the greater the change in wheel speed before processing.

[0055] As reference Figure 3 As shown and explained above, the wheel speed before processing is affected by the slight unevenness of the road surface and the tread pattern of the wheel and changes slightly. Figure 4 As shown and explained, when there is looseness in the connection between the wheel and the hub, the change in the wheel speed before processing is larger than when there is no looseness. Figure 5 As shown and explained above, even if there is no looseness in the connection between the wheel and the hub, when the road surface has large unevenness, the amount of change in wheel speed before processing is larger than when the unevenness is small.

[0056] As reference Figure 2 As shown and described above, the wheel speed sensor 15 transmits the pre-processing wheel speed having such characteristics to the brake ECU 11 .

[0057] <Overview of Fluctuation Values ​​and Fluctuation Amounts Calculated in Determination System 100>

[0058] like Figure 2 As shown in the upper part of , the brake ECU 11 that has received the pre-processing wheel speed calculates the variation value and the variation amount based on the received pre-processing wheel speed.

[0059] In the following, reference is made to Figures 6 to 8 The change value and the change amount are explained below.

[0060] Figure 6 An example of the transition of the wheel speed before processing and the wheel speed after processing calculated based on the wheel speed before processing is shown. Figure 6 In the graph, the dotted line shows the same Figure 3 The graph of wheel speed before treatment is the same as that shown in . Figure 6 The solid line in the graph represents the Figure 3 The change of the wheel speed after processing is calculated from the wheel speed before processing. Figure 6 In, with Figure 3 Likewise, the horizontal axis represents time.

[0061] The post-processing wheel speed is a value obtained by applying a low-pass filter process to the pre-processing wheel speed. Figure 6 The processed wheel speeds shown represent the Figure 3 The values ​​shown are obtained by applying a 2 Hz low-pass filter to the wheel speed before processing. The filter value used in the low-pass filter is not limited to 2 Hz.

[0062] The wheel speed after processing, obtained by applying low-pass filtering to the wheel speed before processing, removes the slight fluctuation in the wheel speed before processing. In other words, the wheel speed after processing reflects the rough fluctuation of the wheel speed before processing. Figure 6 As shown, the wheel speed before processing fluctuates in a manner that fluctuates upward and downward with the wheel speed after processing as the center.

[0063] exist Figure 2 In the upper part of Figure 6 The change value and the change amount are calculated based on the wheel speed before processing and the wheel speed after processing as shown.

[0064] The variation value represents the difference between the wheel speed before processing and the wheel speed after processing. In other words, the variation value represents a slight variation in the wheel speed before processing.

[0065] The change is the absolute value of the change. Figure 7 as well as Figure 8 This is a graph showing an example of the change in the amount of change. Figure 7 as well as Figure 8 In, with Figure 3 Likewise, the horizontal axis represents time.

[0066] Specifically, Figure 7Indicates that it will Figure 6 The change in the difference between the wheel speed before and after the processing is converted into an absolute value. Figure 7 In the part with larger variation, the Figure 6 The divergence between the solid line and the dotted line is also large. Figure 7 In the part where the variation becomes zero, the Figure 6 The solid line overlaps the dotted line.

[0067] Figure 7 The changes shown are based on Figure 3 The wheel speed is calculated before the processing shown. That is, Figure 7 The fluctuation amount shown is an example of the transition of the fluctuation amount when there is no looseness in the connection between the wheel and the hub.

[0068] on the other hand, Figure 8 Indicates based on Figure 4 The change in the wheel speed before processing is shown in FIG. Figure 8 The amount of change shown is an example of the transition of the amount of change when there is looseness in the connection between the wheel and the hub.

[0069] If the Figure 7 and Figure 8 By comparison, we can see that Figure 8 The amplitude of the variation graph shown is Figure 7 The amplitude of the graph of the variation shown is relatively large. Thus, the variation is larger when there is looseness in the connection between the wheel and the hub than when there is no looseness.

[0070] Determination device 21 utilizes the characteristics of this fluctuation value to determine whether the connection between the wheel and the hub has loosened based on the change in the fluctuation value. As previously mentioned, the fluctuation value represents a subtle change in wheel speed before processing. By using the change in the fluctuation value, determination device 21 can detect the occurrence of loose connection between the wheel and the hub at the stage when the fluctuation value begins to change.

[0071] like Figure 2 As shown in the upper section of FIG, the brake ECU 11 calculates the change value and the amount of change based on the pre-processed wheel speed received from the wheel speed sensor 15. The determination device 21 determines the presence of a wheel abnormality based on the transition of the change value calculated by the brake ECU 11, which is directly connected to the wheel speed sensor 15. Because the brake ECU 11 and the wheel speed sensor 15 are directly connected via the communication line 16, they can obtain the pre-processed wheel speed at a high resolution. Therefore, the brake ECU 11 can calculate a precise change value.

[0072] <Overview of Time-Integrated Values ​​Calculated in Determination System 100>

[0073] like Figure 2 As shown in the upper part of , the brake ECU 11 having calculated the change value and the change amount calculates the time integral value of the change amount in a predetermined period. The brake ECU 11 calculates the time integral value regularly.

[0074] In the following, reference is made to Figure 9 as well as Figure 10 The time integral value will be described.

[0075] The time integral value of the variation in a predetermined period is larger when there is looseness in the connection between the wheel and the hub than when there is no looseness. This is because the variation is larger when there is looseness in the connection between the wheel and the hub than when there is no looseness.

[0076] like Figure 5 As shown and explained, even if there is no looseness in the connection between the wheel and the hub, when the road surface is relatively uneven, the change in wheel speed before processing is larger than when the unevenness is smaller. For example, in a situation where the vehicle 10 passes through a large height difference, the amplitude of the change value may sometimes increase instantaneously. In the event of such a transient situation, if the amplitude of the change amount is large, the time integral value of the change amount will become larger. In the event of such a transient situation, the determination device 21 may mistakenly determine that there is looseness in the connection between the wheel and the hub. Therefore, an upper limit value is set for the change amount used to calculate the time integral value used by the determination device 21 in the determination.

[0077] Figure 9 For the calculated Figure 7 In the case of the variation shown in FIG, the variation with the upper limit value is referred to in the determination system 100 in order to calculate the time integral value based on the variation. Figure 9 As shown in the figure, the upper limit of the fluctuation is 0.04. The upper limit is not limited to 0.04. Fluctuations exceeding the upper limit are replaced with a value equal to the upper limit. The upper limit is a cutoff value that defines the upper limit of the fluctuation.

[0078] The upper limit value set in the determination system 100 is set in consideration of the characteristics of the vehicle 10. The characteristics of the vehicle 10 are features of the vehicle 10 that affect the fluctuation value. Examples of the characteristics of the vehicle 10 include the size and weight of the wheels of the vehicle 10. Examples of the characteristics of the vehicle 10 include the weight of the vehicle 10 or the vibration transmissibility of the suspension of the vehicle 10.

[0079] For example, when the characteristics of the vehicle 10 are such that the fluctuation amount is easily reduced, the upper limit value is set low. The upper limit value may be set in advance according to the characteristics of the vehicle 10. The upper limit value may also be calculated based on the history of past fluctuation amount changes.

[0080] The determination device 21 is based on Figure 9 The time integral value of the change amount in a predetermined period as shown above is used to determine whether the connection between the wheel and the hub is loose. Figure 9 The period T1 shown is calculated as the predetermined period. In this manner, the time integral value used for determination by the determination device 21 is calculated using the variation limited by the upper limit value so as not to exceed the upper limit value.

[0081] Figure 10 For the calculated Figure 8 In the case of the variation shown in FIG. 1 , the variation with an upper limit value is referred to in the determination system 100 in order to calculate the time integral value based on the variation. Figure 10 In, also with Figure 9 Similarly, the time-integrated value of the variation amount is calculated using the period T1 as the predetermined period.

[0082] Figure 10 The time integral value of the change amount with the upper limit value shown is greater than Figure 9 Even when an upper limit is set for the fluctuation amount, the time-integrated value of the fluctuation amount when there is looseness in the connection between the wheel and the hub is larger than when there is no looseness.

[0083] like Figure 2 As shown in the upper section of the figure, the brake ECU 11 regularly calculates a time-integrated value based on the amount of change. The determination device 21 uses the time-integrated value of the amount of change over a predetermined period to determine whether the connection between the wheel and the hub is loose. As mentioned above, the wheel speed before processing may also fluctuate significantly and instantaneously due to external factors such as unevenness in the road surface. The determination device 21 makes a judgment using the time-integrated value, which summarizes the magnitude of the amount of change over a predetermined period, enabling accurate determination.

[0084] <Overview of Slope Calculated in Determination System 100>

[0085] like Figure 2 As shown in the upper part of , after calculating the time-integrated value, the brake ECU 11 calculates the slope associated with the calculated time-integrated value.

[0086] In the following, reference is made to Figure 11 Let's explain the slope.

[0087] Figure 11 An example of the transition of the accumulation of time-integrated values ​​calculated in the determination system 100 is shown.

[0088] As described above, the time integral value is calculated periodically. The brake ECU 11 calculates the time integral value every time a predetermined period elapses. Figure 11 The dots shown represent the accumulation of time integral values ​​calculated by the brake ECU 11 for each predetermined period. Figure 11 The value represented by each point shown is a value calculated by adding the calculated time-integrated value to the value represented by the previous point.

[0089] Brake ECU11 image Figure 11 The time integral values ​​calculated for each predetermined period are accumulated in this manner. The brake ECU 11 uses a plurality of time integral values ​​calculated for a longer calculation period than the predetermined period to calculate the slope of the cumulative change of the time integral values ​​during the calculation period. In this embodiment, the calculation period is Figure 11 In Chinese, it is represented by TA.

[0090] The brake ECU 11 calculates the slope based on the accumulation of the time integral values ​​calculated during the calculation period. Figure 11 The straight line shown represents a regression line related to the cumulative change in the time-integrated value. The brake ECU 11 calculates the slope of the regression line as the slope of the cumulative change in the time-integrated value during the calculation period. The determination device 21 determines whether the connection between the wheel and the hub is loose based on the slope calculated in this manner.

[0091] As previously mentioned, the time-integrated value of the change in the amount of wheel-hub coupling over a given period is larger when there is slack than when there is no slack. Therefore, the slope of the cumulative change in the time-integrated value over a given period is larger when there is slack than when there is no slack.

[0092] Based on such characteristics, when the determination device 21 determines that the slope calculated by the brake ECU 11 is greater than the normal slope, it can be determined that there is looseness in the connection between the wheel and the hub. Figure 2 As shown in the upper part of , the brake ECU 11 that has calculated the slope transmits the calculated slope to the central ECU 12 .

[0093] <Processing Method in Central ECU 12>

[0094] Below, in reference Figure 2 At the same time, a method of causing the central ECU 12 to communicate with the determination device 21 so that the determination device 21 determines whether there is looseness in the connection between the wheel and the hub based on the slope will be described.

[0095] like Figure 2 As shown in the middle section of the figure, the central ECU 12, having received the slope, executes a threshold setting process. Although described later, the determination device 21 compares the threshold with the slope to determine whether the wheel-hub connection is loose. During the threshold setting process, the central ECU 12 sets the threshold used by the determination device 21.

[0096] The central ECU 12 pre-stores a reference threshold value in, for example, the storage device 14. During the threshold value setting process, the central ECU 12 corrects the reference threshold value stored in the storage device 14 based on the characteristics of the vehicle 10 to thereby set the threshold value. Alternatively, the central ECU 12 may calculate the reference threshold value based on the past slope history of the vehicle 10, rather than pre-storing the reference threshold value in the storage device 14.

[0097] In the threshold value setting process, the central ECU 12 sets the threshold value in consideration of the characteristics of the vehicle 10. For example, when the characteristics of the vehicle 10 are such that the amount of fluctuation is likely to be large, the threshold value is set high.

[0098] During the threshold value setting process, the central ECU 12 may set a common threshold value for the FR wheel 17, the FL wheel 18, the RR wheel 19, and the RL wheel 20. During the threshold value setting process, the central ECU 12 may set a different threshold value for each of the FR wheel 17, the FL wheel 18, the RR wheel 19, and the RL wheel 20.

[0099] like Figure 2 As shown in the middle section of FIG, the central ECU 12 that has executed the threshold value setting process sends the slope received from the brake ECU 11 to the determination device 21. Figure 2 As shown in the middle section of , the central ECU 12 transmits the threshold value set in the threshold value setting process to the determination device 21 .

[0100] like Figure 2 As shown in the middle section of FIG, the central ECU 12 transmits information indicating the state of the vehicle 10 when transmitting the slope. The state of the vehicle 10 is information related to the running state of the vehicle 10 during the calculation period related to the slope transmitted to the determination device 21.

[0101] The central ECU 12 transmits information indicating the status of the vehicle 10 regarding the functions activated by the vehicle 10 during the calculation period. For example, if the anti-lock braking system is activated, the central ECU 12 transmits information indicating that the anti-lock braking system is activated. For example, if the traction control system is activated, the central ECU 12 transmits information indicating that the traction control system is activated. For example, if the vehicle 10 is activated, the central ECU 12 transmits information indicating that the vehicle 10 is activated. For example, if the vehicle stability control system is activated, the central ECU 12 transmits information indicating that the vehicle stability control system is activated.

[0102] As information indicating the status of the vehicle 10, the central ECU 12 transmits information indicating that the vehicle 10 was traveling on an uneven road during the calculation period. In this case, the central ECU 12 determines that the vehicle 10 was traveling on an uneven road based on, for example, information from a camera included in the vehicle 10. Alternatively, the central ECU 12 can determine that the vehicle 10 was traveling on an uneven road based on, for example, changes in the vehicle's 10 speed.

[0103] The information transmitting device 28 obtains the pre-processing wheel speed detected by the wheel speed sensor 15. Furthermore, the information transmitting device 28 calculates a variation value, which is the difference between the obtained pre-processing wheel speed and the post-processing wheel speed obtained by applying a low-pass filter to the pre-processing wheel speed. The information transmitting device 28 then transmits variation data indicating the transition of the calculated variation value to the determination device 21.

[0104] Information transmitting device 28 periodically calculates a time-integrated value over a predetermined period, which represents the amount of change in the absolute value of the change value. Information transmitting device 28 then uses multiple time-integrated values ​​calculated over a longer inclusion period to calculate the slope of the cumulative change in the included period. Information transmitting device 28 then transmits the calculated slope as change data to determination device 21.

[0105] <Processing Method in Determination Device 21>

[0106] like Figure 2 As shown in the lower section of FIG, the determination device 21 receives the slope, the threshold value, and information indicating the state of the vehicle 10 from the central ECU 12 and then determines whether or not the connection between the wheel and the hub is loose.

[0107] In determining whether the determination is possible, the determination device 21 confirms the received information indicating the state of the vehicle 10 .

[0108] For example, if the vehicle 10 is rapidly decelerating and is not in a normal driving state, the pre-processing wheel speed detected by the wheel speed sensor 15 may no longer be the normal pre-processing wheel speed. If the determination device 21 is based on a change value calculated in such a state, it will be difficult to make an accurate determination.

[0109] When the vehicle 10 is rapidly decelerating, the vehicle 10 is operating the anti-lock braking system. Thus, the function that the vehicle 10 is operating may sometimes reflect that the vehicle 10 is not in a normal driving state. When the vehicle 10 is in a state in which a function that is operated when the vehicle 10 is not in a normal driving state is operating, the determination device 21 does not determine whether the connection between the wheel and the hub is loose. For example, when the information indicating the state of the vehicle 10 indicates that the vehicle 10 is operating the anti-lock braking system, the traction control system, the vehicle stability control system, etc., the determination device 21 does not determine whether the connection between the wheel and the hub is loose.

[0110] Thus, the determination device 21 does not utilize the changes in the calculated variation values ​​based on the pre-processing wheel speeds detected by the wheel speed sensors 15 while the anti-lock braking system of the vehicle 10 is in operation to determine whether a wheel abnormality exists. Furthermore, the determination device 21 does not utilize the changes in the calculated variation values ​​based on the pre-processing wheel speeds detected by the wheel speed sensors 15 while the traction control system of the vehicle 10 is in operation to determine whether a wheel abnormality exists. Furthermore, the determination device 21 does not utilize the changes in the calculated variation values ​​based on the pre-processing wheel speeds detected by the wheel speed sensors 15 while the vehicle stability control system of the vehicle 10 is in operation to determine whether a wheel abnormality exists.

[0111] As mentioned above, even if there is no looseness in the connection between the wheel and the hub, the change in wheel speed before processing is greater when the road surface is relatively uneven than when the road surface is relatively uneven. Therefore, the determination device 21 cannot accurately perform determination on such uneven roads.

[0112] When the determination device 21 receives information indicating that the vehicle 10 is traveling on an uneven road as information indicating the state of the vehicle 10, it does not determine whether the connection between the wheel and the hub is loose. Thus, the determination device 21 does not use the change in the calculated value based on the pre-processing wheel speed detected by the wheel speed sensor 15 while the vehicle 10 is traveling on an uneven road to determine whether there is an abnormality in the wheel.

[0113] like Figure 2 As shown in the lower section of FIG, if the determination device 21 determines that the presence or absence of looseness in the connection between the wheel and the hub is possible, it executes a looseness determination process. In the looseness determination process, the determination device 21 compares the slope received from the central ECU 12 with a threshold value. Furthermore, if the slope is greater than the threshold value, the determination device 21 determines that there is looseness in the connection between the wheel and the hub for the wheel whose pre-processing wheel speed used in calculating the slope is detected.

[0114] like Figure 2 As shown in the lower section of FIG, if the determination device 21 determines that the connection between a wheel and the hub of the vehicle 10 is loose, it sends a warning to the central ECU 12. During the looseness determination process, the determination device 21 compares the slope associated with each of the FR wheel 17, FL wheel 18, RR wheel 19, and RL wheel 20 with a threshold value. If the determination device 21 determines that any of the FR wheel 17, FL wheel 18, RR wheel 19, and RL wheel 20 is loose, it sends a warning to the central ECU 12. The determination device 21 sends a warning message indicating that there is a possibility of loose connection between the wheel and the hub, as well as information indicating the wheel determined to be loose. Based on the received information, the central ECU 12 displays a warning message on the display of the vehicle 10, for example. In this way, when the determination device 21 determines that there is an abnormality in a wheel, it notifies the user of the vehicle 10 of the information indicating the abnormality in the wheel.

[0115] <Function of this embodiment>

[0116] The wheel speed before processing is affected by subtle fluctuations in the road surface and the wheel tread pattern, causing subtle changes. The processed wheel speed, obtained by applying a low-pass filter to the wheel speed before processing, is a value obtained by removing these subtle fluctuations. In other words, the processed wheel speed is a value that reflects the approximate fluctuations in the wheel speed before processing. When a wheel abnormality occurs, the absolute value of the fluctuation increases. By using the change in the value indicating subtle fluctuations in the wheel speed before processing, the determination device 21 can detect the occurrence of an abnormality at the stage where the fluctuation begins to change.

[0117] <Effects of this embodiment>

[0118] (1) According to the above-described determination device 21, it is possible to detect abnormality in a wheel before significantly affecting the driving.

[0119] (2) As an abnormality in the wheel, the determination device 21 determines whether there is any looseness in the connection between the wheel and the hub. When there is looseness in the connection between the wheel and the hub, the variation becomes larger. Since the looseness gradually develops, the variation gradually becomes larger. The determination device 21 uses the transition of the variation value to determine whether there is any looseness. Therefore, the determination device 21 can sense the occurrence of looseness in the middle stage of the looseness development, that is, in the stage before a significant impact occurs in the driving of the vehicle 10.

[0120] (3) The determination device 21 uses the time integral value of the variation amount in a predetermined period, which is the absolute value of the variation value, to determine whether the connection between the wheel and the hub is loose. The time integral value of the variation amount when the connection between the wheel and the hub is in a loose state is larger than when there is no abnormality in the wheel. The time integral value of the variation amount is a value that summarizes information on the size of the variation amount in a predetermined period. The wheel speed before processing sometimes changes greatly instantaneously due to external factors such as the unevenness of the road surface. The above-mentioned determination device 21 determines whether the connection between the wheel and the hub is loose based on the time integral value of the variation amount. In this way, it is possible to suppress the situation where the determination device 21 makes an erroneous judgment based on the change of the instantaneous variation value.

[0121] (4) An upper limit value is set for the fluctuation amount used in calculating the time integral value. The time integral value used by the determination device 21 is calculated using the fluctuation amount limited by the upper limit value so as not to exceed the upper limit value.

[0122] For example, in the case where the vehicle 10 passes through a large height difference, the amplitude of the variation value sometimes increases instantaneously. In the case of such an instantaneous event, if the amplitude of the variation is large, the time integral value of the variation will become larger. Therefore, in the case of such an instantaneous event, the determination device 21 may make an erroneous determination. The time integral value used in the determination by the above-mentioned determination device 21 is calculated using the variation that is limited by the upper limit value in a manner not exceeding the upper limit value. Therefore, even if the amplitude of the variation value increases instantaneously, the variation that is limited by the upper limit value will be reflected in the time integral value. Therefore, the above-mentioned determination device 21 can suppress the influence of the instantaneous event on the determination and thus implement a more accurate determination.

[0123] (5) The time integral value is calculated periodically. The determination device 21 uses a plurality of time integral values ​​calculated during a calculation period that is longer than a predetermined period to calculate a slope of the cumulative change of the time integral value during the calculation period, and determines the presence or absence of loosening of the connection between the wheel and the hub based on the calculated slope.

[0124] If the vehicle 10 continues to travel while the connection between the wheel and the hub is loose, the looseness will gradually develop. Therefore, the time-integrated value of the variation will gradually increase. Therefore, when the looseness is developing, the slope of the cumulative transition of the time-integrated value will change. The determination device 21 uses the slope of the cumulative transition of the time-integrated value to determine whether there is looseness between the wheel and the hub. By monitoring the changes in the slope, the determination device 21 can detect looseness as it develops.

[0125] (6) When the slope exceeds a threshold, the determination device 21 determines that there is slack in the connection between the wheel and the hub. The determination device 21 detects that slack is developing based on the fact that the slope becomes larger than the normal slope. Thus, the determination device 21 can sense that slack is occurring.

[0126] (7) The determination device 21 does not use the change in the variation value calculated based on the pre-processing wheel speed detected by the wheel speed sensor 15 while the vehicle 10 is operating the anti-lock brake system to determine the presence or absence of an abnormality in the wheel.

[0127] The determination device 21 may not be able to accurately determine whether there is an abnormality in the wheel, depending on the driving state of the vehicle 10, such as when the vehicle 10 is rapidly decelerating. Therefore, it is desirable that the vehicle 10 is in a normal driving state when the determination device 21 determines whether there is an abnormality in the wheel.

[0128] When the vehicle 10 is rapidly decelerating, the anti-lock brake system is being activated. The determination device 21 does not determine the presence of an abnormality in the wheel while the anti-lock brake system is being activated. This allows the determination device 21 to prevent erroneous determinations.

[0129] (8) The determination device 21 does not use the change in the variation value calculated based on the pre-processing wheel speed detected by the wheel speed sensor 15 while the vehicle 10 is operating the traction control system to determine the presence or absence of an abnormality in the wheel.

[0130] When the vehicle 10 is operating its traction control system, the determination device 21 cannot make an accurate determination because the vehicle 10 is not in a normal driving state. The determination device 21 does not determine the presence of an abnormality in the wheel while the vehicle 10 is operating its traction control system. This prevents erroneous determinations by the determination device 21.

[0131] (9) The determination device 21 does not use the change in the variation value calculated based on the pre-processing wheel speed detected by the wheel speed sensor 15 while the vehicle 10 is operating the vehicle stability control system to determine whether there is an abnormality in the wheel.

[0132] When the vehicle 10 is operating the vehicle stability control system, the determination device 21 cannot make an accurate determination because the vehicle 10 is not in a normal driving state. When the vehicle 10 is operating the vehicle stability control system, the determination device 21 does not determine whether there is an abnormality in the wheel. This prevents erroneous determinations by the determination device 21.

[0133] (10) The determination device 21 does not use the change in the variation value calculated based on the pre-processing wheel speed detected by the wheel speed sensor 15 while the vehicle 10 is traveling on the uneven road to determine whether there is an abnormality in the wheel.

[0134] When the vehicle 10 is traveling on an uneven road, the determination device 21 cannot make an accurate determination. When the vehicle 10 is traveling on an uneven road, the determination device 21 does not determine whether there is an abnormality in the wheel. This allows the determination device 21 to prevent erroneous determinations.

[0135] (11) The vehicle 10 includes a brake ECU 11, which is an electronic control unit directly connected to the wheel speed sensor 15 via a communication line 16. The determination device 21 determines whether there is an abnormality in the wheel based on the transition of the variation value calculated by the brake ECU 11.

[0136] Because the brake ECU 11 is directly connected to the wheel speed sensor 15 via a communication line 16, it can obtain a highly resolvable pre-processed wheel speed value. Consequently, the brake ECU 11 can accurately calculate the variation value. The determination device 21 determines the presence of a wheel abnormality based on the variation value calculated by the brake ECU 11. This allows the determination device 21 to perform a highly accurate determination.

[0137] (12) The information transmitting device 28 obtains the pre-processing wheel speed detected by the wheel speed sensor 15. The information transmitting device 28 calculates a variation value, which is the difference between the obtained pre-processing wheel speed and the post-processing wheel speed obtained by applying a low-pass filter to the pre-processing wheel speed. The information transmitting device 28 transmits variation data indicating the transition of the calculated variation value to the determination device 21.

[0138] Thus, the information transmitting device 28 can cause the determination device 21 to determine whether or not there is an abnormality in the wheel.

[0139] (13) The information transmitting device 28 periodically calculates the time-integrated value of the absolute value of the change amount during a predetermined period. The information transmitting device 28 uses the multiple time-integrated values ​​calculated during a longer inclusion period to calculate the slope of the cumulative change of the time-integrated values ​​during the inclusion period. The information transmitting device 28 transmits the calculated slope as change data to the determination device 21.

[0140] Thus, the information transmitting device 28 can cause the determining device 21 to determine the presence or absence of an abnormality in the wheel based on the gradient of the transition of the cumulative time-integrated value.

[0141] (14) The determination system 100 includes an information transmitting device 28 and a determination device 21. The information transmitting device 28 obtains the wheel speed before processing detected by the wheel speed sensor 15. The information transmitting device 28 calculates a variation value that is the difference between the obtained wheel speed before processing and the wheel speed after processing obtained by applying a low-pass filter process to the wheel speed before processing. The information transmitting device 28 transmits variation data indicating the transition of the calculated variation value to the determination device 21. The determination device 21 determines whether there is an abnormality in the wheel based on the received variation data. When the determination device 21 determines that there is an abnormality in the wheel, it notifies the user of the vehicle 10 of information indicating that there is an abnormality in the wheel.

[0142] The determination system 100 determines the presence of an abnormality in the wheel by observing the transition of the variation value. Thus, the determination system 100 can notify the user of the presence of an abnormality in the wheel before it significantly affects the driving.

[0143] (15) In the determination system 100, the determination device 21 determines whether there is loosening of the connection between the wheel and the hub as an abnormality in the wheel. Thus, the determination system 100 can warn the user of the occurrence of loosening at a stage in which the loosening is developing, that is, before it significantly affects the driving of the vehicle 10.

[0144] <Change Example>

[0145] This embodiment can be implemented by modifying the following aspects: This embodiment and the following modifications can be implemented in combination with each other within a range that does not technically conflict.

[0146] In the above-described embodiment, the determination device 21 determines whether the connection between the wheel and the hub is loose as a wheel abnormality. However, the wheel abnormality determined by the determination device 21 is not limited to loose connection between the wheel and the hub. For example, the determination device 21 can detect improper wheel air pressure as a wheel abnormality. For example, the determination device 21 can detect whether one of the multiple wheels on the vehicle 10 is a studless tire.

[0147] In the above-described embodiment, the determination device 21 determines whether the FR wheel 17, FL wheel 18, RR wheel 19, and RL wheel 20 are loose in connection with the wheel hub. The number of wheels for which the determination device 21 determines whether there is looseness is not limited to the above-described embodiment. For example, the determination device 21 may determine only whether there is looseness in the connection between the FR wheel 17 and the FR hub 24. In this case, the information transmitting device 28 does not need to include wheel speed sensors 15 corresponding to wheels other than the FR wheel 17.

[0148] In the above embodiment, if Figure 1 As shown and described above, the brake ECU 11 and the wheel speed sensor 15 are connected by wire via the communication line 16. Alternatively, the brake ECU 11 and the wheel speed sensor 15 may be connected wirelessly.

[0149] In the above embodiment, if Figure 2 As shown and explained, the determination device 21 determines whether the determination is possible before executing the relaxation determination process. In the determination system 100, the information transmitting device 28 may also perform the determination whether the determination is possible.

[0150] For example, the central ECU 12 in the information transmitting device 28 determines whether the determination device 21 can execute the slack determination process based on information indicating the state of the vehicle 10. Furthermore, if the central ECU 12 determines that the determination device 21 cannot execute the slack determination process, it does not transmit information such as the slope to the determination device 21.

[0151] In the above embodiment, as shown in FIG. Figure 2 As shown in FIG, the determination device 21 determines whether the determination can be made before executing the relaxation determination process. The determination device 21 may not determine whether the determination can be made but always executes the determination. In this case, the central ECU 12 Figure 2 There is no need to transmit information indicating the characteristics of the vehicle 10 in the middle section.

[0152] In the above embodiment, as shown in FIG. Figure 2 As shown and described, the brake ECU 11 calculates the change value and the amount of change. The brake ECU 11 may not be the only one to calculate the change value and the amount of change. For example, the central ECU 12 may calculate the change value and the amount of change based on the wheel speed before processing. Furthermore, for example, the determination device 21 may calculate the change value and the amount of change based on the wheel speed before processing.

[0153] In the above embodiment, as shown in FIG. Figure 2 As shown and described, the brake ECU 11 calculates the time-integrated value. However, the time-integrated value may be calculated by a different unit than the brake ECU 11. For example, the central ECU 12 may calculate the time-integrated value based on the amount of change. For example, the determination device 21 may calculate the time-integrated value based on the amount of change.

[0154] In the above embodiment, as shown in FIG. Figure 2 As shown and described, the brake ECU 11 calculates the slope. However, the brake ECU 11 may not be the only one to calculate the slope. For example, the central ECU 12 may calculate the slope based on the time-integrated value. For example, the determination device 21 may calculate the slope based on the time-integrated value.

[0155] In the above embodiment, as shown in FIG. Figure 2 As shown and described above, the central ECU 12 sets the threshold value. However, the determination device 21 may also set the threshold value.

[0156] Figure 12FIG. 2 shows a method of communication performed among the brake ECU 11, the central ECU 12, the wheel speed sensor 15, and the determination device 21 in the determination system 100 of the first modified example. Figure 12 In the example, the processing performed by the central ECU 12 is performed by the processing circuit 13. Figure 12 In the example, the processing performed by the determination device 21 is performed by the processing circuit 22.

[0157] exist Figure 12 The communication method from the wheel speed sensor 15 sending the wheel speed before processing to the brake ECU 11 sending the slope is the same as Figure 2 same.

[0158] exist Figure 12 In the middle section, the central ECU 12 receives the slope and sends the received slope, information indicating the characteristics of the vehicle 10, and information indicating the state of the vehicle 10 to the determination device 21. The determination device 21 receives the information from the central ECU 12 and determines whether the wheel and hub are loose. At this time, the processing performed by the determination device 21 is the same as that in Figure 2 The processing performed by the lower section determination device 21 is the same.

[0159] like Figure 12 As shown in the lower section of FIG, if the determination device 21 determines that the presence or absence of looseness in the connection between the wheel and the hub is possible, it executes a threshold setting process. The determination device 21, for example, pre-stores a reference threshold value in the storage device 23. During the threshold setting process, the determination device 21 corrects the reference threshold value stored in the storage device 23 based on the characteristics of the vehicle 10 to set the threshold value. Alternatively, the determination device 21 may calculate the reference threshold value based on the past slope history of the vehicle 10, rather than pre-storing the reference threshold value in the storage device 23.

[0160] During the threshold value setting process, the determination device 21 sets a common threshold value for the FR wheel 17, the FL wheel 18, the RR wheel 19, and the RL wheel 20. During the threshold value setting process, the determination device 21 may set a different threshold value for each of the FR wheel 17, the FL wheel 18, the RR wheel 19, and the RL wheel 20.

[0161] like Figure 12As shown in the lower section of FIG, after executing the threshold setting process, the determination device 21 performs a slack determination process. In the slack determination process, the determination device 21 compares the slope received from the central ECU 12 with a threshold value set by the determination device 21. If the slope is greater than the threshold value, the determination device 21 determines that there is slack in the connection with the hub for the wheel whose pre-processing wheel speed used in the slope calculation was detected.

[0162] like Figure 12 As shown in the lower part of FIG, when the determination device 21 determines that there is looseness in the connection between the wheel and the hub of the vehicle 10, it sends a warning to the central ECU 12. The processing performed here is the same as that in Figure 2 The process of the determination device 21 sending a warning to the central ECU 12 is the same as in the lower section.

[0163] In the above embodiment, as shown in FIG. Figure 2 As shown in the middle section of FIG, the central ECU 12 executes a threshold setting process. In the threshold setting process, the central ECU 12 sets the threshold by correcting the reference threshold. The central ECU 12 may also set the threshold based on the past slope history of the wheel to be determined.

[0164] Figure 13 FIG. 2 shows an example of the transition of the accumulation of the time integral value calculated in the determination system 100 of the second modification. Figure 13 The included period represented by TA is the same as that in Figure 11 The calculation period represented by TA is the same as that in Figure 13 In the example, each period of TB, TC, TD, TE, and TF represents the same period as in Figure 11 The included periods represented by TA in are included periods of the same length. Figure 13 In the table, TA, TB, TC, TD, TE, and TF represent the included periods.

[0165] Figure 13 The cumulative change of the time-integrated value shown is calculated based on the wheel speed before processing detected in the FR wheel 17, for example. Figure 13 From the middle of the TD period, the loosening of the connection between the FR wheel 17 and the FR hub 24 begins to develop.

[0166] like Figure 13As shown, the slope calculated based on the time-integrated value of the FR wheel 17 increases from the time TD. The slope calculated based on the time-integrated value of the FR wheel 17 gradually increases after TD. This is because if the vehicle 10 continues to travel with slack in the connection between the wheel and the hub, the slack gradually develops, causing the time-integrated value of the variation to gradually increase. Thus, the slope calculated based on the time-integrated value of the wheel increases as the slack develops, starting from the point at which slack occurs.

[0167] The determination device 21 can determine that the connection between the target wheel and the hub has loosened when the slope calculated based on the time integral value of the target wheel becomes larger than the previous slope of the same wheel.

[0168] Figure 14 1 shows data stored in the storage device 14 for the central ECU 12 to set the threshold value in the determination system 100 of the second modified example. Figure 14 As shown, the central ECU 12 stores the slope calculated based on the time-integrated value at the wheel to be determined in the storage device 14 in association with the respective calculation periods.

[0169] exist Figure 14 middle, Figure 13 The slope of the TA period is A1. Figure 14 In the form of A1, A2, A3, the symbols are used to express Figure 13 In the determination system 100 of the second modified example, when performing determination on each of the FR wheel 17 , the FL wheel 18 , the RR wheel 19 , and the RL wheel 20 , the central ECU 12 stores the slope for each wheel.

[0170] As reference Figure 2 As described above, the brake ECU 11 transmits the calculated slope to the central ECU 12. The central ECU 12 sets the threshold value using a moving average of the received slopes. The central ECU 12 stores three slopes received from the brake ECU 11, in descending order. The central ECU 12 then sets the threshold value based on these three stored slopes. For example, the central ECU 12 sets the threshold value to a value that is greater than the average of the three stored slopes.

[0171] Hereinafter, an example will be given for explanation. For example, it is assumed that the central ECU 12 Figure 14The central ECU 12 receives the slope during the TD period from the brake ECU 11 while storing the slopes during the TA, TB, and TC periods shown in FIG. Figure 2 In the threshold setting process shown, Figure 14 The central ECU 12 sets the larger value than the average of A1, A2, and A3 in the TA period as the threshold value. Thereafter, the central ECU 12 discards A1, the slope during the TA period, and stores A4, the slope during the TD period, in the storage device 14. In this way, the central ECU 12 updates the slope stored in the storage device 14 and sets the threshold value based on the stored slope.

[0172] The number of slopes stored in the central ECU 12 is not limited to the number described in the second modification, and the method by which the central ECU 12 sets the threshold based on past slopes is not limited to setting a value larger than the average of the stored slopes as the threshold.

[0173] In the second modification, the threshold is set by the central ECU 12. As in the first modification, the threshold may be set by the determination device 21. In this case, the determination device 21 sets the threshold based on the slope stored in the storage device 23.

[0174] In this manner, the determination device 21 can determine whether or not there is looseness in the connection between the wheel and the hub using a threshold value set based on the past slope of the wheel to be determined.

[0175] In this case, the determination device 21 uses a threshold value set based on the past slope of the wheel being determined. As slack develops, the slope of the time-integrated value increases. The determination device 21 detects developing slack based on data obtained from the wheel being determined. This allows the determination device 21 to detect the occurrence of wheel slack.

[0176] In the above embodiment, as shown in FIG. Figure 2 As shown in the middle section of FIG, the central ECU 12 executes a threshold setting process. In the threshold setting process, the central ECU 12 sets the threshold by correcting the reference threshold. Alternatively, the central ECU 12 may set the threshold based on the slope of the time-integrated value for a wheel not subject to determination among the multiple wheels of the vehicle 10.

[0177] Figure 15 FIG. 2 shows an example of the transition of the accumulation of the time integral value calculated in the determination system 100 of the third modification. Figure 15 In the period of TA Figure 11 The TA period shown is the same. Figure 15 Each period of TB, TC, TD, TE, and TF is also related to Figure 11 The TA period shown is the same. Figure 15 In the table, TA, TB, TC, TD, TE, and TF represent the included periods.

[0178] exist Figure 15 In FIG, the transition of the time integral value in the FR wheel 17 and the FL wheel 18 is collectively shown. Figure 15 In, with Figure 13 Likewise, from midway through the TD period, the loosening of the connection between the FR wheel 17 and the FR hub 24 begins to develop.

[0179] like Figure 15 As shown, the slope of FR wheel 17 before the TD period is the same as the slope of FL wheel 18 during the same time period. Some factors affecting the pre-processing wheel speed may uniformly affect the pre-processing wheel speed of each wheel in vehicle 10. For example, changes in road conditions may uniformly affect the pre-processing wheel speed of each wheel on the same vehicle. Therefore, during a period when no such factors affecting the pre-processing wheel speed of a specific wheel in vehicle 10 are present, the slope of FR wheel 17 is substantially the same as the slopes of other wheels during the same time period.

[0180] like Figure 15 As shown, the slope calculated based on the time-integrated value for FR wheel 17 increases with the TD period as the boundary. Furthermore, the slope for FR wheel 17 after the TD period becomes larger than the slope for the FL wheel 18 during the same time period. Thus, if the connection between one of the multiple wheels on the same vehicle and the hub becomes loose, the slope associated with the loosened wheel will become larger than the slopes associated with the other wheels.

[0181] When the slope calculated for the wheel to be determined becomes larger than the slopes of other wheels in the same time period, the determination device 21 can determine that the connection between the wheel to be determined and the hub has loosened.

[0182] Hereinafter, it will be described what kind of processing is executed in the determination system 100 of the third modification example.

[0183] In the determination system 100 of the third modified example, the central ECU 12 obtains the slopes in the same time period of the FR wheel 17, the FL wheel 18, the RR wheel 19, and the RL wheel 20. Figure 2As described above, the brake ECU 11 transmits the calculated slope to the central ECU 12. In the third modified example, the central ECU 12 starts the threshold setting process when the slopes of the FR wheels 17, FL wheels 18, RR wheels 19, and RL wheels 20 in the same time period are made consistent.

[0184] During the threshold setting process, the central ECU 12 calculates the average of the slopes during the same time period for wheels other than those being determined, among the multiple wheels of the vehicle 10. For example, when setting the threshold for determining the FR wheel 17, the central ECU 12 calculates the average of the slopes during the same time period for the FL wheel 18, the RR wheel 19, and the RL wheel 20. The central ECU 12 then sets the threshold based on the calculated average. For example, the central ECU 12 sets a larger value than the calculated average as the threshold for the FR wheel 17.

[0185] The method by which the central ECU 12 sets the threshold value based on the slope of a wheel not subject to determination among the plurality of wheels of the vehicle 10 is not limited to that described in the third modified example. For example, the central ECU 12 may set a larger value as the threshold value corresponding to the FR wheel 17 than the slope of the FL wheel 18 in the same time period.

[0186] In the third modification, the threshold is set by the central ECU 12. As in the first modification, the threshold may be set by the determination device 21. In this case, the determination device 21 obtains information on the slopes of the plurality of wheels from the brake ECU 11.

[0187] In this manner, the determination device 21 can determine whether the connection between the wheel and the hub is loose using a threshold value set based on the slope in the same time period of a wheel that is not the subject of determination among the multiple wheels of the vehicle 10.

[0188] In this case, the determination device 21 uses a value set based on the slope of the same time period in the wheels that are not the objects of determination among the multiple wheels of the vehicle 10 as a threshold value. In the event that the connection with the hub of any of the multiple wheels becomes loose, the slope of the loose wheel will become larger than the slopes of the other wheels. Among the main factors that affect the wheel speed before processing, there are also cases such as changes in road conditions that uniformly affect the wheel speed before processing of each wheel in the same vehicle. The determination device 21 determines the presence or absence of looseness by comparing the slopes of the wheels of the same vehicle. In this way, the determination device 21 can suppress erroneous determinations caused by the main factors that uniformly affect the wheel speed before processing of each wheel.

[0189] In the above-described embodiment, the determination device 21 determines whether the connection between the wheel and the hub is loose based on the slope of the time-integrated value calculated based on the amount of wheel fluctuation. In order for the determination device 21 to determine whether the connection between the wheel and the hub is loose, it is not necessary to calculate the time-integrated value or the slope. For example, the determination device 21 may also determine whether the connection between the wheel and the hub is loose based on the number of convergences in the fluctuation value.

[0190] In the following, it is shown Figure 16 as well as Figure 17 Let's explain the number of convergences.

[0191] Figure 16 For Figure 7 The same graph as the change in the amount shown. In other words, Figure 16 The amount of change shown is an example of the transition of the amount of change when there is no looseness in the connection between the wheel and the hub.

[0192] for Figure 16 A predetermined range is set for the change in the amount of change shown. The predetermined range is a range set with zero as the center for the change value. Figure 16 In FIG, since the amount of change is shown as the absolute value of the change value, the prescribed range is shown corresponding to the amount of change.

[0193] exist Figure 16 In the example, the limit value of the prescribed range is 0.04. The limit value of the prescribed range is set in consideration of the characteristics of vehicle 10. For example, if the characteristics of vehicle 10 are such that the fluctuation amount is easily reduced, the limit value of the prescribed range is set lower. The limit value of the prescribed range may also be set in accordance with the characteristics of vehicle 10 in advance. Alternatively, the limit value of the prescribed range may be a value calculated based on the history of the change in the past fluctuation amount.

[0194] The scope of the method is not limited to Figure 16 The limit value of the specified range is not limited to 0.04. Figure 16 In the example, the predetermined range is set for the amount of change, which is the absolute value of the change value. On the other hand, the determination system 100 can also set the predetermined range for the change value by setting two values, 0.04 and -0.04, as the limit values ​​of the predetermined range.

[0195] The number of convergences is the sum of the number of times the variation value changes from outside the specified range to within the specified range and the number of times the variation value changes from within the specified range to outside the specified range during the counting period. Figure 16 In the example, T1 represents the counting period. Figure 16 In the example, circles are used to highlight the positions where the variation changes from outside the specified range to within the specified range, and the positions where the variation changes from within the specified range to outside the specified range. Figure 16 The number of circles in .

[0196] The number of convergences may include the case where the change value reaches the limit value of the specified range from outside the specified range and then changes back to outside the specified range. The number of convergences may also include the case where the change value reaches the limit value of the specified range from within the specified range and then changes back to the specified range.

[0197] Figure 17 For Figure 8 The same graph as the change in the amount shown. In other words, Figure 17 The fluctuation amount shown is an example of the change amount when there is looseness in the connection between the wheel and the hub. Figure 17 In, also with Figure 16 Similarly, a specified range is set. Figure 17 In, also with Figure 16 Similarly, the position where the amount of change changes from outside the prescribed range to within the prescribed range, and the position where the amount of change changes from within the prescribed range to outside the prescribed range are emphasized using circles.

[0198] If the Figure 16 and Figure 17 By comparison, we can see that Figure 17 The number of convergences in Figure 16 Thus, when there is looseness in the connection between the wheel and the hub, the convergence number is smaller than when there is no looseness.

[0199] Figure 18FIG. 4 shows a method of communication performed between the brake ECU 11, the central ECU 12, the wheel speed sensor 15, and the determination device 21 in the determination system 100 of the fourth modification. Figure 18 In the example, the processing performed by the central ECU 12 is performed by the processing circuit 13. Figure 18 In the embodiment, the processing performed by the determination device 21 is performed by the processing circuit 22. In the determination system 100 of the fourth modification, the determination device 21 determines whether there is looseness in the connection between the wheel and the hub based on the number of convergences.

[0200] like Figure 18 As shown in the upper section of FIG, in the determination system 100 of the fourth modified example, the wheel speed sensor 15 transmits the pre-processed wheel speed to the brake ECU 11. Upon receiving the pre-processed wheel speed, the brake ECU 11 calculates the change value and the change amount based on the received pre-processed wheel speed. In the determination system 100 of the fourth modified example, if a predetermined range is set for the change value, calculation of the change amount is unnecessary.

[0201] like Figure 18 As shown in the upper part of , the brake ECU 11 having calculated the variation value and the variation amount calculates the number of convergences during the counting period. The brake ECU 11 having calculated the number of convergences transmits the number of convergences to the central ECU 12 .

[0202] like Figure 18 As shown in the middle section of FIG, the central ECU 12 receives the number of convergence times and executes the threshold setting process. In the threshold setting process, the central ECU 12 executes the same process as the Figure 2 The method shown is the same as that shown. Specifically, the central ECU 12 pre-stores the reference threshold value in the storage device 14, for example. During the threshold setting process, the central ECU 12 corrects the reference threshold value stored in the storage device 14 based on the characteristics of the vehicle 10 to thereby set the threshold value. Alternatively, the central ECU 12 may calculate the reference threshold value based on the history of past convergence times in the vehicle 10, rather than pre-storing the reference threshold value in the storage device 14.

[0203] like Figure 18 As shown in the middle section of FIG, the central ECU 12 with the threshold set sends the convergence number, the threshold, and information indicating the state of the vehicle 10. The information indicating the state of the vehicle 10 is the same as Figure 2 The information shown in the middle section of is the same. In this way, the information transmitting device 28 calculates the number of convergences. The information transmitting device 28 transmits the calculated number of convergences to the determination device 21.

[0204] like Figure 18As shown in the lower part of FIG, the determination device 21 receives the convergence number, threshold value, and information indicating the state of the vehicle 10 from the central ECU 12 and determines whether the loosening of the connection between the wheel and the hub can be determined. The determination device 21 determines whether the loosening of the connection between the wheel and the hub can be determined in the same way as the determination device 21. Figure 2 The same way as shown in the next paragraph.

[0205] like Figure 18 As shown in the lower part of FIG, the judging device 21 performs a loosening judging process when it is judged that the loosening of the connection between the wheel and the hub can be judged. In the loosening judging process, the judging device 21 Figure 18 The number of convergences received in the middle section is compared with the threshold.

[0206] As previously mentioned, the convergence count decreases when there is looseness in the connection between the wheel and the hub compared to when there is no looseness. Therefore, the determination device 21 can determine that there is looseness in the connection between the wheel and the hub when the convergence count becomes less than the normal convergence count. When the convergence count is below a threshold, the determination device 21 determines that there is looseness in the connection between the wheel and the hub for the wheel whose pre-processing wheel speed was detected and used in calculating the convergence count. In this way, the determination device 21 compares the received convergence count with the threshold to determine whether the convergence count is less than the normal convergence count.

[0207] like Figure 18 As shown in the lower part of FIG, the determination device 21 sends a warning to the central ECU 12 when it is determined that there is looseness in the connection between the wheel and the hub of the vehicle 10. The determination device 21 sends a warning in the same manner as in Figure 2 The same method is shown in the lower paragraph.

[0208] In this manner, in the determination system 100 of the fourth modified example, the determination device 21 can determine the presence or absence of looseness in the connection between the wheel and the hub based on the number of convergences.

[0209] The determination device 21 determines whether the connection between the wheel and the hub is loose based on the number of convergences, which is calculated by summing the number of times the variation value changes from outside the specified range centered on zero to within the specified range and the number of times the variation value changes from within the specified range to outside the specified range during the counting period. If looseness occurs, the variation value becomes difficult to converge to a value close to zero. Therefore, if looseness occurs, the number of convergences will be smaller than if no looseness occurs. Therefore, the determination device 21 can determine whether looseness exists based on the number of convergences.

[0210] When the number of convergences falls below a threshold, the determination device 21 determines that there is loosening between the wheel and the hub. The determination device 21 detects that loosening is developing based on the number of convergences falling below a normal number of convergences. This allows the determination device 21 to detect that loosening is occurring.

[0211] Information transmitting device 28 calculates the number of convergences, which is the sum of the number of times the variation value changes from outside the specified range centered on zero to within the specified range and the number of times the variation value changes from within the specified range to outside the specified range during the counting period. Information transmitting device 28 transmits the calculated number of convergences to determination device 21.

[0212] Thus, the information transmitting device 28 can cause the determination device 21 to determine the presence or absence of an abnormality in the wheel based on the number of convergence times.

[0213] In the fourth modification, the central ECU 12 is as shown in FIG. Figure 18 As shown in the middle section of FIG, the threshold setting process is executed. In the threshold setting process, the central ECU 12 sets the threshold by correcting the reference threshold. The central ECU 12 may also set the threshold based on the history of past convergence times for the wheel to be determined.

[0214] Figure 19 An example of the transition of the number of convergences obtained in the determination system 100 is shown. Figure 19 In the number of convergences shown, T1, T2, T3, T4, T5, and T6 represent count periods.

[0215] Figure 19 The transition of the convergence frequency shown is calculated based on, for example, the wheel speed before processing detected in the FR wheel 17. Figure 19 From the middle of the period T4, the loosening of the connection between the FR wheel 17 and the FR hub 24 begins to develop.

[0216] like Figure 19 As shown, the number of convergences in the FR wheel 17 decreases sharply starting from the period T4. The number of convergences in the FR wheel 17 decreases gradually after the period T4. Thus, the number of convergences in the wheel decreases as the loosening progresses, starting from the point at which the connection between the wheel and the hub begins to loosen.

[0217] In this way, when the number of convergences acquired for a wheel to be determined becomes smaller than the past number of convergences for the same wheel, the determination device 21 can determine that the connection between the wheel and the hub has loosened.

[0218] Figure 201 shows data stored in the storage device 14 in order for the central ECU 12 to set a threshold value in the determination system 100 of the fifth modified example. Figure 20 As shown, the central ECU 12 stores the number of convergences during the counting period for the wheel to be determined in the storage device 14. Figure 20 middle, Figure 19 The number of convergences in the time period T1 is B1. Figure 20 In the form of B1, B2, B3, symbols are used to express Figure 19 In the determination system 100 of the fifth modified example, when the central ECU 12 performs determination on each of the FR wheel 17 , the FL wheel 18 , the RR wheel 19 , and the RL wheel 20 , it stores the convergence count for each wheel.

[0219] As reference Figure 18 As described in the upper section of FIG, the brake ECU 11 transmits the acquired convergence count to the central ECU 12. The central ECU 12 sets the threshold value by using the moving average of the received convergence counts. The central ECU 12 stores three convergence counts received from the brake ECU 11, in descending order. The central ECU 12 then sets the threshold value based on the three stored convergence counts. For example, the central ECU 12 sets the threshold value to a smaller value than the average of the three stored convergence counts.

[0220] Hereinafter, an example will be given for explanation. For example, it is assumed that the central ECU 12 Figure 20 In the state where the convergence counts during the periods T1, T2, and T3 shown in FIG. 1 are stored, the convergence count during the period T4 is received from the brake ECU 11. At this time, the central ECU 12 Figure 18 In the threshold setting process shown, Figure 20 The central ECU 12 sets the smaller value than the average of B1, B2, and B3 in the above data as the threshold value. Thereafter, the central ECU 12 discards B1, the number of convergences during T1, and stores B4, the number of convergences during T4, in the storage device 14. In this way, the central ECU 12 updates the number of convergences stored in the storage device 14 and sets the threshold value based on the stored number of convergences.

[0221] The number of convergence times stored by the central ECU 12 is not limited to the number described in the fifth modification. The method by which the central ECU 12 sets the threshold based on past convergence times is not limited to setting a value smaller than the average of the stored convergence times as the threshold.

[0222] In the fifth modification, the threshold is set by the central ECU 12. As in the first modification, the threshold may be set by the determination device 21. In this case, the determination device 21 sets the threshold based on the number of convergences stored in the storage device 23.

[0223] In this manner, the determination device 21 can determine whether or not there is looseness in the connection between the wheel and the hub using a threshold value set based on the past number of convergences in the wheel to be determined.

[0224] In this case, the determination device 21 uses a threshold value set based on the past convergence counts for the wheel being determined. As slack progresses, the convergence counts decrease. The determination device 21 detects developing slack based on data obtained from the wheel being determined. This allows the determination device 21 to detect the occurrence of loosening in the connection between the wheel and the hub.

[0225] In the fourth modification, as shown in FIG. Figure 18 The central ECU 12 may set the threshold value based on the number of convergences at a wheel that is not a target of determination among the plurality of wheels included in the vehicle 10 .

[0226] Figure 21 An example of the transition of the number of convergences obtained in the determination system 100 is shown. Figure 21 In the number of convergences shown, T1, T2, T3, T4, T5, and T6 represent count periods.

[0227] exist Figure 21 In FIG, the convergence frequency of the FR wheel 17 and the FL wheel 18 included in the vehicle 10 is shown. Figure 21 In , the white circles indicate the number of convergences in FR wheel 17. Figure 21 In , the black circles represent the number of convergences in the FL wheel 18. Figure 21 In, with Figure 19 Likewise, from the middle of the period T4, the loosening of the connection between the FR wheel 17 and the FR hub 24 begins to develop.

[0228] The convergence count before T4 for the FR wheel 17 does not differ significantly from the convergence count for the FL wheel 18 during the same time period. As previously mentioned, some of the factors affecting the pre-processing wheel speed may uniformly affect the pre-processing wheel speed of each wheel in the vehicle 10. Therefore, during a period when no such factors affecting the pre-processing wheel speed of a specific wheel in the vehicle 10 occur, the convergence count for the FR wheel 17 is substantially the same as the convergence count for the other wheels during the same time period.

[0229] like Figure 21 As shown, the number of convergences for FR wheel 17 decreases with period T4 as the boundary. Furthermore, the number of convergences for FR wheel 17 after period T4 is less than the number of convergences for FL wheel 18 during the same period. Thus, if the connection between one of the multiple wheels on a vehicle and the hub becomes loose, the number of convergences for the loosened wheel will become less than the number of convergences for the other wheels.

[0230] When the number of convergences obtained in the wheel to be determined becomes smaller than the number of convergences in the same time period of other wheels, the determination device 21 can determine that loosening of the connection with the hub has occurred in the wheel to be determined.

[0231] Hereinafter, it will be described what kind of processing is executed in the determination system 100 according to the sixth modification.

[0232] In the determination system 100 of the sixth modified example, the central ECU 12 obtains the number of convergences in the same time period of the FR wheel 17, the FL wheel 18, the RR wheel 19, and the RL wheel 20. Figure 18 As described in the upper section of FIG, the brake ECU 11 transmits the calculated number of convergences to the central ECU 12. In the sixth modified example, when the central ECU 12 successfully obtains the number of convergences in the same time period for all of the FR wheels 17, FL wheels 18, RR wheels 19, and RL wheels 20, it starts executing the threshold value setting process.

[0233] During the threshold setting process, the central ECU 12 calculates the average number of convergences during the same time period for wheels other than those being determined, among the multiple wheels of the vehicle 10. For example, when setting the threshold for determining the FR wheel 17, the central ECU 12 calculates the average number of convergences during the same time period for the FL wheel 18, the RR wheel 19, and the RL wheel 20. The central ECU 12 then sets the threshold based on the calculated average. For example, the central ECU 12 sets a smaller value than the calculated average as the threshold for the FR wheel 17.

[0234] The method by which the central ECU 12 sets the threshold value based on the number of convergences at a wheel not subject to determination among the plurality of wheels of the vehicle 10 is not limited to that described in the sixth modified example. For example, the central ECU 12 may set a smaller value than the number of convergences at the FL wheel 18 in the same time period as the threshold value corresponding to the FR wheel 17.

[0235] In the sixth modification, the threshold is set by the central ECU 12. As in the first modification, the threshold may be set by the determination device 21. In this case, the determination device 21 obtains information on the number of convergences related to the plurality of wheels from the brake ECU 11.

[0236] In this manner, the determination device 21 can determine whether the connection between the wheel and the hub is loose using a threshold value set based on the number of convergences in the same time period in wheels other than the determination target among the plurality of wheels of the vehicle 10 .

[0237] In this case, the determination device 21 uses, as the threshold value, a value set based on the number of convergences in the same time period at wheels that are not the subject of determination among the plurality of wheels included in the vehicle 10 .

[0238] If any of the multiple wheels becomes loose in connection with the hub, the convergence count for the loosened wheel will be smaller than the convergence count for the other wheels. Among the main factors that affect the pre-processing wheel speed, there are cases where changes in road conditions, such as changes in road conditions, uniformly affect the pre-processing wheel speed for each wheel on the same vehicle. The determination device 21 determines the presence or absence of looseness by comparing the convergence counts for the multiple wheels on the same vehicle. Thus, the determination device 21 can suppress erroneous determinations caused by main factors that uniformly affect the pre-processing wheel speed for each wheel.

Claims

1. A determination device, comprising: obtaining variation data indicating a change in a variation value, the variation value being a difference between a pre-processing wheel speed detected by a wheel speed sensor for detecting a rotational speed of a wheel of a vehicle and a post-processing wheel speed obtained by applying a low-pass filter to the pre-processing wheel speed, and The presence or absence of abnormality in the wheel is determined based on the variation data.

2. The determination device according to claim 1, wherein: The anomaly in the wheel includes loosening of the coupling of the wheel to the hub.

3. The determination device according to claim 2, wherein: The variation data includes a time-integrated value of a variation amount, which is an absolute value of the variation value, over a predetermined period.

4. The determination device according to claim 3, wherein: An upper limit is set for the variation. The time-integrated value is calculated using the variation limited by the upper limit value so as not to exceed the upper limit value.

5. The determination device according to claim 3 or claim 4, wherein: The variation data includes a slope of a transition of the accumulation of the time-integrated value in a calculation period, the calculation period being longer than the predetermined period, The slope is calculated using the plurality of time-integrated values ​​calculated during the calculation period.

6. The determination device according to claim 5, wherein: The determination device is configured to determine that there is looseness in the connection between the wheel and the hub when the slope becomes equal to or greater than a threshold value.

7. The determination device according to claim 6, wherein: The threshold value is set based on the past slope of the wheel to be determined.

8. The determination device according to claim 6, wherein: The wheels include wheels that are the subject of determination and wheels that are not the subject of determination. The threshold value is set based on the slope of the wheel that is not the subject of determination, The slope used for setting the threshold value is acquired in the same time period as the time period in which the slope of the wheel to be determined is acquired.

9. The determination device according to claim 2, wherein: The variation data includes a convergence count, which is a total of the number of times the variation value changes from outside a predetermined range centered on zero to within the predetermined range and the number of times the variation value changes from within the predetermined range to outside the predetermined range during a counting period.

10. The determination device according to claim 9, wherein: The determination device is configured to determine that there is looseness in the connection between the wheel and the hub when the number of convergence times becomes equal to or smaller than a threshold value.

11. The determination device according to claim 10, wherein: The threshold value is set based on the past convergence count for the wheel to be determined.

12. The determination device according to claim 10, wherein: The wheels include wheels that are the subject of determination and wheels that are not the subject of determination. The threshold value is set based on the number of convergences in the wheel that is not the subject of determination. The number of convergences used for setting the threshold value is acquired in the same time period as the time period in which the number of convergences in the wheel to be determined is acquired.

13. The determination device according to claim 1 or claim 2, wherein: The determination device is configured not to use the variation data obtained based on the pre-processing wheel speed detected when the vehicle is in a specific state in determining the presence or absence of an abnormality in the wheel. The specific state includes at least one of the following states: The vehicle is in a state where the anti-lock braking system is in operation, The vehicle is in a state where the traction control system is in operation, The vehicle is in a state where a vehicle stability control system is in operation, and The vehicle is traveling on an uneven road.

14. The determination device according to claim 1 or claim 2, wherein: The vehicle includes an electronic control device, and the electronic control device and the wheel speed sensor are directly connected via a communication line. The determination device is configured to determine the presence or absence of an abnormality in the wheel based on the variation data calculated by the electronic control device.

15. An information transmitting device, comprising: Obtaining the wheel speed before processing detected by a wheel speed sensor that detects the rotation speed of a wheel provided in the vehicle, The post-processing wheel speed is obtained by applying a low-pass filter process to the pre-processing wheel speed. calculating a variation value which is a difference between the wheel speed before the processing and the wheel speed after the processing, and The variation data indicating the transition of the variation value is transmitted to the determination device according to any one of claims 1 to 14.

16. The information transmitting device according to claim 15, wherein: The information sending device is configured as follows: The time integral value of the variation amount, which is the absolute value of the variation value, in a predetermined period is calculated periodically. The slope of the transition of the accumulation of the time-integrated values ​​in the calculation period is calculated using the plurality of time-integrated values ​​calculated in the calculation period, the calculation period being longer than the predetermined period, and The slope is sent to the determination device as the variation data.

17. The information transmitting device according to claim 15, wherein: The information sending device is configured as follows: The convergence number is calculated, which is the sum of the number of times the variation value changes from outside the prescribed range centered on zero to within the prescribed range and the number of times the variation value changes from within the prescribed range to outside the prescribed range during the counting period, and The number of convergences is sent to the determination device as the variation data.

18. A determination system comprising an information transmitting device and a determination device, wherein: The information sending device is configured as follows: Obtaining the wheel speed before processing detected by a wheel speed sensor that detects the rotation speed of a wheel provided in the vehicle, The post-processing wheel speed is obtained by applying a low-pass filter process to the pre-processing wheel speed. calculating a variation value which is a difference between the wheel speed before the processing and the wheel speed after the processing, and sending the change data indicating the transition of the change value to the determination device, The determination device is configured as follows: determining whether or not there is an abnormality in the wheel based on the variation data, and When it is determined that the wheel has an abnormality, information indicating that the wheel has an abnormality is notified to the user of the vehicle.

19. The determination system according to claim 18, wherein: The anomaly in the wheel includes loosening of the coupling of the wheel to the hub.

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