Information processing device

Abstract

To determine whether there is wheel loosening, on the basis of a parameter different from a wheel speed.SOLUTION: An information processing device acquires actual lateral acceleration that is an actual measured value of lateral acceleration of a vehicle detected by an acceleration sensor mounted on the vehicle, over a prescribed period that is predetermined (S31). The information processing device acquires estimated lateral acceleration that is an estimated value of the lateral acceleration, over the prescribed period on the basis of a parameter different from the actual lateral acceleration (S31). The information processing device calculates an error of the actual lateral acceleration with respect to the estimated lateral acceleration on the basis of the estimated lateral acceleration and the actual lateral acceleration that have been acquired over the prescribed period (S32). The information processing device determines that there is wheel loosening in the vehicle on a condition that the calculated error is equal to or greater than a prescribed value that is predetermined (S33).SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Patent Document 1 discloses a method for detecting that a wheel is not properly fixed to an axle of a vehicle, i.e., that the wheel is loose. In the looseness detection method of Patent Document 1, a wheel speed signal indicating the rotation speed of the wheel of the vehicle is acquired over a certain period of time. In addition, in the looseness detection method, a correction signal is calculated by correcting the acquired wheel speed signal. In addition, in the looseness detection method, a signal obtained by applying a low-pass filter to the calculated correction signal is calculated. In addition, in the looseness detection method, an error of the correction signal with respect to the low-pass filtered signal is calculated based on the correction signal and a signal obtained by applying a low-pass filter to the correction signal. In addition, in the looseness detection method, whether or not the wheel of the vehicle is loose is determined based on the calculated error. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2018-506470 Summary of the Invention [Problem to be solved by the invention]

[0004] The looseness detection method of Patent Document 1 determines whether or not a vehicle wheel has looseness based on the rotation speed of the wheel. On the other hand, Patent Document 1 does not pay any attention to determining whether a wheel has looseness based on parameters other than the rotation speed of the wheel. [Means for solving the problem]

[0005] An information processing device for solving the above problem performs the following steps: acquires actual lateral acceleration, which is an actual measured value of the lateral acceleration of the vehicle detected by an acceleration sensor mounted on the vehicle, over a predetermined specified period; acquires estimated lateral acceleration, which is an estimated value of the lateral acceleration, over the specified period based on a parameter other than the actual lateral acceleration; calculates an error of the actual lateral acceleration relative to the estimated lateral acceleration based on the estimated lateral acceleration and the actual lateral acceleration acquired over the specified period; and determines that loosening has occurred in the wheels of the vehicle, provided that the calculated error is greater than or equal to a predetermined specified value. Effect of the Invention

[0006] According to the above configuration, the presence or absence of slack in the wheel can be determined based on the error between the actual lateral acceleration and the estimated lateral acceleration. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram of an information processing system. [Diagram 2] FIG. 2 is a functional block diagram showing the basic configuration of the exercise manager. [Diagram 3] FIG. 3 is a sequence diagram showing collection control, determination control, and distribution control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] <Outline of information processing system configuration> An embodiment of the present invention will now be described with reference to Figures 1 to 3. First, a schematic configuration of an information processing system IS will be described.

[0009] As shown in Fig. 1, the information processing system IS includes a plurality of vehicles 100. An example of the vehicles 100 is a standard automobile having four wheels. Therefore, the vehicle 100 includes a total of four wheels, a right front wheel, a left front wheel, a right rear wheel, and a left rear wheel. Note that Fig. 1 illustrates only one of the vehicles 100 as a representative example.

[0010] The vehicle 100 is equipped with a powertrain device 71, a steering device 72, and a braking device 73. The powertrain device 71 includes an engine, a motor generator, a transmission, etc. The engine can apply driving force to the drive wheels of the vehicle 100 via the transmission. The motor generator can apply driving force to the drive wheels of the vehicle 100 via the transmission.

[0011] An example of the steering device 72 is a rack-and-pinion type electric steering device. The steering device 72 can change the direction of the steered wheels of the vehicle 100 by controlling a rack and pinion (not shown).

[0012] The brake device 73 is a so-called mechanical brake device that mechanically brakes the wheels of the vehicle 100. In this embodiment, an example of the brake device 73 is a disc brake.

[0013] 1, the vehicle 100 includes a central ECU 10, a powertrain ECU 20, a steering ECU 30, a brake ECU 40, and an advanced driving assistance ECU 50. The vehicle 100 also includes a first external bus 61, a second external bus 62, a third external bus 63, a fourth external bus 64, and a fifth external bus 65. Note that "ECU" is an abbreviation for Electronic Control Unit.

[0014] The central ECU 10 centrally controls the entire vehicle 100. The central ECU 10 includes an execution device 11 and a storage device 12. An example of the execution device 11 is a CPU. The storage device 12 includes a read-only ROM, a readable and writable volatile RAM, and a readable and writable non-volatile storage. The storage device 12 stores various programs and various data in advance. The execution device 11 executes the programs stored in the storage device 12 to realize various processes.

[0015] The powertrain ECU 20 can communicate with the central ECU 10 via a first external bus 61. The powertrain ECU 20 controls the powertrain device 71 by outputting a control signal to the powertrain device 71. The powertrain ECU 20 includes an execution device 21 and a storage device 22. An example of the execution device 21 is a CPU. The storage device 22 includes a ROM, a RAM, and a storage. The storage device 22 stores various programs and various data in advance. The storage device 22 also stores a powertrain application 23A in advance as one of the various programs. The powertrain application 23A is application software for controlling the powertrain device 71. The execution device 21 executes the powertrain application 23A stored in the storage device 22 to realize a function as a powertrain control unit 23 described later.

[0016] The steering ECU 30 can communicate with the central ECU 10 via the second external bus 62. The steering ECU 30 controls the steering device 72 by outputting a control signal to the steering device 72. The steering ECU 30 includes an execution device 31 and a storage device 32. An example of the execution device 31 is a CPU. The storage device 32 includes a ROM, a RAM, and a storage. The storage device 32 stores various programs and various data in advance. The storage device 32 also stores a steering application 33A in advance as one of the various programs. The steering application 33A is application software for controlling the steering device 72. The execution device 31 executes the steering application 33A stored in the storage device 32 to realize a function as a steering control unit 33 described later.

[0017] The brake ECU 40 can communicate with the central ECU 10 via the third external bus 63. The brake ECU 40 controls the brake device 73 by outputting a control signal to the brake device 73. The brake ECU 40 includes an execution device 41 and a storage device 42. An example of the execution device 41 is a CPU. The storage device 42 includes a ROM, a RAM, and a storage. The storage device 42 stores various programs and various data in advance. The storage device 42 also stores a brake application 43A in advance as one of the various programs. The brake application 43A is application software for controlling the brake device 73. The storage device 42 also stores an exercise manager application 45A in advance as one of the various programs. The exercise manager application 45A is application software for mediating a plurality of exercise requests. The execution device 41 executes the brake application 43A stored in the storage device 42 to realize a function as a brake control unit 43 described later. Moreover, the execution device 41 executes an exercise manager application 45A stored in the storage device 42 to realize the function of an exercise manager 45, which will be described later.

[0018] The advanced driving assistance ECU 50 can communicate with the central ECU 10 via a fourth external bus 64. The advanced driving assistance ECU 50 executes various driving assistance functions. The advanced driving assistance ECU 50 includes an execution device 51 and a storage device 52. An example of the execution device 51 is a CPU. The storage device 52 includes a ROM, a RAM, and a storage. The storage device 52 stores various programs and various data in advance. The various programs include a first support application 56A, a second support application 57A, and a third support application 58A. An example of the first support application 56A is application software for a collision damage mitigation brake that automatically applies the brakes to reduce damage caused by a collision to the vehicle 100, so-called AEB (Autonomous Emergency Braking). An example of the second support application 57A is application software for a lane keeping assistance that maintains the lane in which the vehicle 100 is traveling, so-called LKA (Lane Keeping Assist). An example of the third support application 58A is application software for so-called ACC (Adaptive Cruise Control), which is a follow-up driving mode in which the vehicle 100 drives while maintaining a constant distance from a preceding vehicle that drives ahead of the vehicle 100. In this embodiment, each of the first support application 56A, the second support application 57A, and the third support application 58A is application software for implementing a driving support function of the vehicle 100. The execution device 51 implements a function as a first support unit 56, which will be described later, by executing the first support application 56A stored in the storage device 52. In addition, the execution device 51 implements a function as a second support unit 57, which will be described later, by executing the second support application 57A stored in the storage device 52. The execution device 51 implements a function as a third support unit 58, which will be described later, by executing the third support application 58A stored in the storage device 52.

[0019] 1, the vehicle 100 includes an acceleration sensor 81, a wheel speed sensor 82, and a GNSS receiver 83. The vehicle 100 also includes an accelerator operation amount sensor 86, a steering angle sensor 87, and a brake operation amount sensor 88.

[0020] The acceleration sensor 81 is a so-called three-axis sensor. That is, the acceleration sensor 81 can detect longitudinal acceleration GX, lateral acceleration GY, and vertical acceleration GZ. The longitudinal acceleration GX is acceleration along the longitudinal axis of the vehicle 100. The lateral acceleration GY is acceleration along the lateral axis of the vehicle 100. The vertical acceleration GZ is acceleration along the lateral axis of the vehicle 100. In this embodiment, the lateral acceleration GY is an actual measured value of the lateral acceleration of the vehicle 100 detected by the acceleration sensor 81, that is, the actual lateral acceleration.

[0021] The wheel speed sensor 82 detects a wheel speed WS, which is the rotation speed of the wheels of the vehicle 100. The wheel speed sensor 82 is located near each wheel of the vehicle 100. In this embodiment, the vehicle 100 is equipped with four wheel speed sensors 82 corresponding to the four wheels equipped on the vehicle 100. Note that only one wheel speed sensor 82 is shown representatively in FIG.

[0022] The GNSS receiver 83 detects position coordinates PC, which are the coordinates of the location of the vehicle 100, by communicating with a GNSS satellite (not shown). Note that "GNSS" is an abbreviation for Global Navigation Satellite System.

[0023] The accelerator operation amount sensor 86 detects the accelerator operation amount ACC, which is the amount of operation of the accelerator pedal operated by the driver. The steering angle sensor 87 detects the steering angle SA, which is the angular position of the steering wheel operated by the driver. The brake operation amount sensor 88 detects the brake operation amount BRA, which is the amount of operation of the brake pedal operated by the driver.

[0024] The powertrain ECU 20 obtains a signal indicating the accelerator operation amount ACC from the accelerator operation amount sensor 86. The steering ECU 30 obtains a signal indicating the steering angle SA from the steering angle sensor 87. The brake ECU 40 obtains signals indicating the longitudinal acceleration GX, the lateral acceleration GY, and the vertical acceleration GZ from the acceleration sensor 81. The brake ECU 40 also obtains a signal indicating the position coordinate PC from the GNSS receiver 83. The brake ECU 40 obtains signals indicating the four wheel speeds WS from the four wheel speed sensors 82. The brake ECU 40 obtains a signal indicating the brake operation amount BRA from the brake operation amount sensor 88. The brake ECU 40 can obtain various values ​​including the accelerator operation amount ACC and the steering angle SA via the central ECU 10.

[0025] The brake ECU 40 calculates the vehicle speed SP, which is the speed of the vehicle 100, at each predetermined control cycle. For example, the brake ECU 40 calculates the vehicle speed SP by multiplying the average value of the four wheel speeds WS by a predetermined coefficient. That is, the brake ECU 40 is able to obtain the vehicle speed SP.

[0026] As shown in FIG. 1, the vehicle 100 includes a DCM 91 and a display 92. The DCM 91 is connected to the central ECU 10 via a fifth external bus 65. The DCM 91 is capable of wireless communication with devices outside the vehicle 100 via a communication network NW. Note that "DCM" is an abbreviation for Data Communication Module. The display 92 is connected to the central ECU 10. The display 92 is capable of displaying various types of information based on image data output from the central ECU 10.

[0027] As shown in FIG. 1, the information processing system IS includes a server 200. The server 200 includes an execution unit 210, a memory unit 220, and a communication unit 230. The communication unit 230 is capable of communicating with devices external to the server 200 via a communication network NW. The memory unit 220 includes a ROM, a RAM, and a storage. The memory unit 220 stores various programs and various data in advance. An example of the execution unit 210 is a CPU. The execution unit 210 realizes various processes by executing various programs stored in the memory unit 220. In this embodiment, the server 200 is an example of an information processing device.

[0028] As shown in FIG. 1, the information processing system IS includes a plurality of personal terminals 300. An example of the personal terminal 300 is a mobile terminal, a so-called smartphone, owned by a user of the vehicle 100. Note that FIG. 1 illustrates only one personal terminal 300 as a representative. The personal terminal 300 includes an execution unit 310, a storage unit 320, and a communication unit 330. The communication unit 330 can communicate with devices outside the personal terminal 300 via a communication network NW. The storage unit 320 includes a ROM, a RAM, and a storage. The storage unit 320 stores various programs and various data in advance. An example of the execution unit 310 is a CPU. The execution unit 310 realizes various processes by executing various programs stored in the storage unit 320.

[0029] <Basic configuration of the exercise manager> Next, a basic configuration of the motion manager 45 will be described with reference to Fig. 2. As shown in Fig. 2, the motion manager 45 can communicate with a first support unit 56, a second support unit 57, and a third support unit 58. In addition, the motion manager 45 can communicate with the powertrain control unit 23, the steering control unit 33, and the brake control unit 43.

[0030] The first support unit 56, the second support unit 57, and the third support unit 58 output an exercise request to the exercise manager 45 when executing various controls. At this time, the first support unit 56, the second support unit 57, and the third support unit 58 continue to output the exercise request, for example, from when various controls become necessary until the controls are no longer necessary. Here, the exercise request includes a required longitudinal acceleration GXR for controlling the acceleration along the longitudinal axis of the vehicle 100, and the like.

[0031] The exercise manager 45 receives the requested longitudinal acceleration GXR as an exercise request from the first support unit 56, the second support unit 57, and the third support unit 58. The exercise manager 45 also arbitrates the received requested longitudinal acceleration GXR. For example, when the exercise manager 45 receives the requested longitudinal acceleration GXR from a plurality of support units, the exercise manager 45 selects the requested longitudinal acceleration GXR that was received the earliest as the arbitration result. For example, when the exercise manager 45 receives the requested longitudinal acceleration GXR from a plurality of support units, the exercise manager 45 selects the smallest requested longitudinal acceleration GXR as the arbitration result. In this way, the exercise manager 45 arbitrates the exercise requests according to a rule that is predetermined according to the driving situation of the vehicle 100.

[0032] The motion manager 45 generates an instruction signal of an operation request for controlling various actuators based on the required longitudinal acceleration GXR selected as the arbitration result. Here, the various actuators are the powertrain device 71, the steering device 72, the brake device 73, etc. For example, when controlling the powertrain device 71, the motion manager 45 outputs an instruction signal of an operation request to the powertrain control unit 23. Then, the powertrain control unit 23 outputs a control signal to the powertrain device 71 based on the instruction signal of the operation request. In this way, the instruction signal output by the motion manager 45 is received by the control unit corresponding to the actuator to be controlled, and the actuator is controlled by the control unit.

[0033] Each of the powertrain control unit 23, the steering control unit 33, and the brake control unit 43 can receive an instruction signal of an operation request from the driver of the vehicle 100 in addition to an instruction signal of an operation request from the motion manager 45. When the powertrain control unit 23, the steering control unit 33, and the brake control unit 43 receive an instruction signal of an operation request from the driver of the vehicle 100, the powertrain control unit 23, the steering control unit 33, and the brake control unit 43 output a control signal to the actuator based on the instruction signal of the operation request from the driver of the vehicle 100. That is, when the powertrain control unit 23 receives an instruction signal of an operation request from the driver of the vehicle 100, each control unit disables the instruction signal of the operation request from the motion manager 45. The powertrain control unit 23 can receive an accelerator operation amount ACC from the accelerator operation amount sensor 86 as an instruction signal of an operation request for controlling the actuator based on the operation of the driver. The steering control unit 33 can receive a steering angle SA from the steering angle sensor 87 as an instruction signal of an operation request for controlling the actuator based on the operation of the driver. Furthermore, the brake control unit 43 can receive a brake operation amount BRA from a brake operation amount sensor 88 as an instruction signal of an operation request for controlling the actuator based on the operation of the driver.

[0034] <Collection Control> Next, the collection control executed by the vehicle 100 and the server 200 will be described with reference to Fig. 3. This collection control is a control for the server 200 to collect various values ​​from the vehicle 100. The collection control is executed in parallel between a plurality of vehicles 100 and one server 200. In this embodiment, the motion manager 45 of the vehicle 100 executes the collection control at each predetermined control period.

[0035] As shown in Fig. 3, when the motion manager 45 of the vehicle 100 starts collection control, it executes the process of step S11. In step S11, the motion manager 45 judges whether or not a predetermined prerequisite is satisfied. In this embodiment, the motion manager 45 judges that the prerequisite is satisfied when all of the following requirements (1) to (4) are satisfied.

[0036] Requirement (1): All sensors and ECUs are functioning normally. Requirement (2): The amount of change per unit time of the vehicle speed SP is equal to or less than a predetermined reference amount of change.

[0037] Requirement (3): The amount of change in the steering angle SA per unit time must be less than a predetermined specific amount of change. Requirement (4): The vehicle speed SP is within a predetermined reference speed range.

[0038] Here, the reference speed region is determined in advance as a region of the vehicle speed SP for ensuring the accuracy of the determination control described later through experiments, simulations, etc. An example of the reference speed region is about 10 km / h to several tens of km / h.

[0039] In step S11, if the exercise manager 45 determines that the prerequisites are not satisfied, the exercise manager 45 ends the current collection control. On the other hand, in step S11, if the exercise manager 45 determines that the prerequisites are satisfied, the exercise manager 45 advances the process to step S12.

[0040] In step S12, the motion manager 45 generates collected data DC. In this embodiment, the motion manager 45 generates data including the vehicle speed SP, the steering angle SA, the lateral acceleration GY, the four wheel speeds WS, etc. as the collected data DC. After step S12, the motion manager 45 advances the process to step S13.

[0041] In step S13, the motion manager 45 of the vehicle 100 transmits the collected data DC to the server 200. As a result, the execution unit 210 of the server 200 acquires the collected data DC. At this time, the execution unit 210 of the server 200 stores the acquired collected data DC in the storage unit 220. Note that by repeatedly executing the collection control, the execution unit 210 of the server 200 can acquire the collected data DC transmitted from each vehicle 100 in chronological order. After step S13, the execution unit 210 of the server 200 ends the current collection control.

[0042] <Decision control> Next, the determination control executed by the server 200 will be described with reference to Fig. 3. This determination control is a control for determining whether or not looseness has occurred in the wheels of the vehicle 100. In this embodiment, the execution unit 210 of the server 200 executes the determination control on the condition that the collected data DC has been continuously acquired from the same vehicle 100 over a predetermined specified period by the above-mentioned collection control. Here, an example of the specified period is about several seconds to a dozen seconds.

[0043] 3, when the execution unit 210 of the server 200 starts the determination control, it executes the process of step S31. In step S31, the execution unit 210 acquires the lateral acceleration GY for the specified period from the collected data DC for the specified period. In this embodiment, when the vehicle 100 is turning left, the lateral acceleration GY has a positive value. On the other hand, when the vehicle 100 is turning right, the lateral acceleration GY has a negative value.

[0044] The execution unit 210 also acquires the steering angle SA and the vehicle speed SP for the specified period from the collected data DC for the specified period. The execution unit 210 then calculates an estimated lateral acceleration GYE, which is an estimated value of the lateral acceleration of the vehicle 100, based on the steering angle SA and the vehicle speed SP. For example, in the case of a steering angle SA such that the vehicle 100 is turning left, the estimated lateral acceleration GYE is a positive value. On the other hand, for example, in the case of a steering angle SA such that the vehicle 100 is turning right, the estimated lateral acceleration GYE is a negative value. The execution unit 210 calculates the estimated lateral acceleration GYE over the specified period. In this embodiment, the estimated lateral acceleration GYE is an estimated value of the lateral acceleration of the vehicle 100 acquired based on the steering angle SA and the vehicle speed SP, which are parameters different from the lateral acceleration GY.

[0045] Furthermore, the execution unit 210 acquires four wheel speeds WS for the specified period from the collected data DC for the specified period. In other words, the execution unit 210 acquires the wheel speeds WS of the right front wheel, the left front wheel, the right rear wheel, and the left rear wheel of the vehicle 100 over the specified period. After step S31, the execution unit 210 advances the process to step S32.

[0046] In step S32, the execution unit 210 calculates an acceleration error DG, which is the mean square error of the lateral acceleration GY with respect to the estimated lateral acceleration GYE, based on the estimated lateral acceleration GYE and the lateral acceleration GY acquired over a specified period. As described above, the collected data DC is acquired for each predetermined control period. Therefore, the estimated lateral acceleration GYE and the lateral acceleration GY within the specified period exist as a plurality of values ​​for each control period. In the following, it is assumed that there are N pieces of data for each of the estimated lateral acceleration GYE and the lateral acceleration GY within the specified period. Note that "N" is an integer of 2 or more. In addition, the N pieces of data are, in order from the oldest to the oldest, the data at the first time point, the data at the second time point, ..., the data at the Nth time point. In step S32, the execution unit 210 calculates a value obtained by squaring the difference between the estimated lateral acceleration GYE at the first time point and the lateral acceleration GY at the first time point. In addition, the execution unit 210 calculates a value obtained by squaring the difference between the estimated lateral acceleration GYE at the second time point and the lateral acceleration GY at the second time point. Similarly to the above, the execution unit 210 calculates the squared difference between the estimated lateral acceleration GYE and the lateral acceleration GY for the third time point to the Nth time point. Then, the execution unit 210 calculates the average of the N values ​​calculated as above as the acceleration error DG. In this embodiment, the acceleration error DG is an example of the error of the lateral acceleration GY with respect to the estimated lateral acceleration GYE. After step S32, the execution unit 210 advances the process to step S33.

[0047] In step S33, the execution unit 210 determines the degree of looseness of the wheels of the vehicle 100 based on the acceleration error DG. Specifically, the execution unit 210 determines the degree of looseness of the wheels as follows. Here, the execution unit 210 uses a first specified value A1, a second specified value A2, and a third specified value A3 that are determined in advance. The second specified value A2 is a value larger than the first specified value A1. In addition, the third specified value A3 is a value larger than the second specified value A2. Note that the first specified value A1, the second specified value A2, and the third specified value A3 are determined in advance as threshold values ​​for determining the degree of looseness of the wheels through experiments, simulations, etc.

[0048] The execution unit 210 determines that the wheel is in a first state where no looseness occurs when the acceleration error DG is less than the first specified value A1. The execution unit 210 determines that the wheel is in a second state where looseness occurs when the acceleration error DG is equal to or greater than the first specified value A1 and less than the second specified value A2. The execution unit 210 determines that the wheel is in a third state where looseness occurs when the acceleration error DG is equal to or greater than the second specified value A2 and less than the third specified value A3. This third state is a state in which the wheel is looser than the second state. The execution unit 210 determines that the wheel is in a fourth state where looseness occurs when the acceleration error DG is equal to or greater than the third specified value A3. This fourth state is a state in which the wheel is looser than the third state. In this way, the execution unit 210 determines that the wheel is not loose when the acceleration error DG is less than the first specified value A1. Moreover, the execution unit 210 determines that the wheel is loose when the acceleration error DG is equal to or greater than the first specified value A1.

[0049] Each time the execution unit 210 determines the degree of looseness of the wheel, it stores the degree of looseness in the storage unit 220. Furthermore, if the newly determined degree of looseness is greater than the past degree of looseness stored in the storage unit 220, the execution unit 210 associates the newly determined degree of looseness with information on the date and time when the determination was made and stores the information in the storage unit 220. For example, it is assumed that the maximum value of the past degrees of looseness stored in the storage unit 220 is the second state. In this case, in step S33, if the execution unit 210 determines that the degree of looseness of the wheel is the third state or the fourth state, it associates the newly determined degree of looseness with information on the date and time when the determination was made and stores the information in the storage unit 220. After step S33, the execution unit 210 advances the process to step S34.

[0050] In step S34, the execution unit 210 calculates a first wheel speed error DW1, which is a mean square error between the wheel speeds WS of the right front wheel and the left front wheel, based on the wheel speeds WS of the right front wheel and the left front wheel of the vehicle 100 acquired over a specified period. Specifically, the execution unit 210 calculates a value obtained by squaring the difference between the wheel speed WS of the right front wheel at a first time point and the wheel speed WS of the left front wheel at the first time point. The execution unit 210 also calculates a value obtained by squaring the difference between the wheel speed WS of the right front wheel at a second time point and the wheel speed WS of the left front wheel at the second time point. Similarly to the above, the execution unit 210 calculates a value obtained by squaring the difference between the wheel speed WS of the right front wheel and the wheel speed WS of the left front wheel for the third time point to the Nth time point. Then, the execution unit 210 calculates the average value of the N values ​​calculated as above as the first wheel speed error DW1. In this embodiment, the first wheel speed error DW1 is an example of an error between the wheel speed WS of the right front wheel and the wheel speed WS of the left front wheel.

[0051] In the same manner as above, the execution unit 210 calculates a second wheel speed error DW2, which is a mean square error between the wheel speed WS of the right rear wheel and the wheel speed WS of the left rear wheel, based on the wheel speed WS of the right rear wheel and the wheel speed WS of the left rear wheel of the vehicle 100 acquired over a specified period. In this embodiment, the second wheel speed error DW2 is an example of an error between the wheel speed WS of the right rear wheel and the wheel speed WS of the left rear wheel. In addition, the execution unit 210 calculates a third wheel speed error DW3, which is a mean square error between the wheel speed WS of the right front wheel and the wheel speed WS of the right rear wheel, based on the wheel speed WS of the right front wheel and the wheel speed WS of the right rear wheel of the vehicle 100 acquired over a specified period. In this embodiment, the third wheel speed error DW3 is an example of an error between the wheel speed WS of the right front wheel and the wheel speed WS of the right rear wheel. Furthermore, the execution unit 210 calculates a fourth wheel speed error DW4, which is a mean square error between the wheel speed WS of the left front wheel and the wheel speed WS of the left rear wheel, based on the wheel speed WS of the left front wheel and the wheel speed WS of the left rear wheel of the vehicle 100 acquired over a specified period. In this embodiment, the fourth wheel speed error DW4 is an example of an error between the wheel speed WS of the left front wheel and the wheel speed WS of the left rear wheel. After step S34, the execution unit 210 advances the process to step S35.

[0052] In step S35, the execution unit 210 identifies a wheel of the vehicle 100 that is most likely to have looseness, based on the first wheel speed error DW1, the second wheel speed error DW2, the third wheel speed error DW3, and the fourth wheel speed error DW4. Specifically, the execution unit 210 identifies the top two values ​​of the first wheel speed error DW1, the second wheel speed error DW2, the third wheel speed error DW3, and the fourth wheel speed error DW4. Here, the top value means a larger value. Then, the execution unit 210 identifies the wheels associated with the top two values ​​identified above, among the right front wheel, the left front wheel, the right rear wheel, and the left rear wheel of the vehicle 100, as the wheels that are most likely to have looseness, on the condition that the acceleration error DG is equal to or greater than the first specified value A1. For example, it is assumed that the top two values ​​identified above are the first wheel speed error DW1 and the third wheel speed error DW3. In this case, the wheel speed WS of the right front wheel is used to calculate the first wheel speed error DW1 and the third wheel speed error DW3. Therefore, in this example, the execution unit 210 identifies the right front wheel, which is the wheel related to the top two values ​​identified above, as the wheel most likely to have looseness. If there is no wheel related to the top two values ​​identified above, the execution unit 210 determines that it is not possible to identify the wheel. After step S35, the execution unit 210 ends the current determination control.

[0053] <Distribution control> Next, the delivery control executed by the personal terminal 300 and the server 200 will be described with reference to Fig. 3. This delivery control is a control for transmitting the determination information IJ from the server 200 to the personal terminal 300. The determination information IJ will be described in detail later. The delivery control is executed in parallel between the multiple personal terminals 300 and one server 200. The vehicle 100 and the personal terminal 300 of the vehicle 100 are linked in advance. In this embodiment, every time the user of the vehicle 100 requests the execution of the delivery control by operating the personal terminal 300, the execution unit 310 of the personal terminal 300 executes the delivery control.

[0054] 3, when the execution unit 310 of the personal terminal 300 starts distribution control, it executes the process of step S51. In step S51, the execution unit 310 of the personal terminal 300 transmits a request signal to the server 200 to request transmission of the determination information IJ. Then, when the execution unit 210 of the server 200 receives the request signal, the execution unit 210 of the server 200 advances the process to step S52.

[0055] In step S52, the execution unit 210 of the server 200 generates determination information IJ. Specifically, the execution unit 210 generates information including the determination result of step S33 and the identification result of step S35 as the determination information IJ. That is, the determination information IJ includes the determination result of whether or not looseness has occurred in the wheels of the vehicle 100. After step S52, the execution unit 210 advances the process to step S53.

[0056] In step S53, the execution unit 210 of the server 200 transmits the determination information IJ to the personal terminal 300. As a result, the execution unit 310 of the personal terminal 300 acquires the determination information IJ. At this time, the execution unit 310 of the personal terminal 300 notifies the user of the vehicle 100 of the determination information IJ via a display or the like of the personal terminal 300. After step S53, the execution unit 310 of the personal terminal 300 ends the current distribution control.

[0057] <Action of this embodiment> For example, assume that a nut for fixing a wheel to a hub of the vehicle 100 becomes loose. When such a looseness occurs in the wheel of the vehicle 100, the behavior of the vehicle 100 is likely to become unstable when the vehicle 100 is traveling. Therefore, there are many occasions where the estimated lateral acceleration GYE, which is an estimated value of the lateral acceleration of the vehicle 100 derived based on the steering angle SA, etc., diverges from the lateral acceleration GY, which is an actual measured value of the lateral acceleration of the vehicle 100 detected by the acceleration sensor 81. As a result, the acceleration error DG, which is the mean square error of the lateral acceleration GY with respect to the estimated lateral acceleration GYE, becomes large due to the looseness of the wheel of the vehicle 100.

[0058] <Effects of this embodiment> (1) In step S32 of the determination control, the execution unit 210 of the server 200 calculates an acceleration error DG, which is the mean square error of the lateral acceleration GY with respect to the estimated lateral acceleration GYE, based on the estimated lateral acceleration GYE and the lateral acceleration GY acquired over a specified period. Then, in step S33, the execution unit 210 determines that the wheels of the vehicle 100 are loose when the acceleration error DG is equal to or greater than a first specified value A1. As a result, the presence or absence of looseness in the wheels can be determined based on the acceleration error DG.

[0059] (2) In step S33 of the judgment control, the execution unit 210 of the server 200 judges the degree of looseness of the wheels of the vehicle 100 based on the acceleration error DG. Specifically, when the acceleration error DG is less than the first specified value A1, the execution unit 210 judges that the vehicle is in a first state in which the wheels are not loose. When the acceleration error DG is equal to or greater than the first specified value A1 and less than the second specified value A2, the execution unit 210 judges that the vehicle is in a second state in which the wheels are loose. When the acceleration error DG is equal to or greater than the second specified value A2 and less than the third specified value A3, the execution unit 210 judges that the vehicle is in a third state in which the wheels are looser than the second state. When the acceleration error DG is equal to or greater than the third specified value A3, the execution unit 210 judges that the vehicle is in a fourth state in which the wheels are looser than the third state. In this way, by determining the degree of wheel looseness in three or more stages rather than in two stages, that is, looseness is present or not, a more precise and user-friendly determination result can be obtained.

[0060] (3) In step S33 of the judgment control, the execution unit 210 of the server 200 stores the degree of looseness in the memory unit 220 each time it judges the degree of looseness of the wheel. Furthermore, when the newly judged degree of looseness is greater than the past degree of looseness stored in the memory unit 220, the execution unit 210 links the newly judged degree of looseness to information on the date and time when the judgment was made and stores the information in the memory unit 220. Therefore, when the degree of looseness of the wheel increases, information on the date and time at that time is stored in the memory unit 220. This makes it possible to identify, for example, the time when maintenance of the vehicle 100 should be performed based on the information on the date and time when the degree of looseness of the wheel increased.

[0061] (4) For example, let us assume that the right front wheel of the vehicle 100 is loose among the right front wheel, the left front wheel, the right rear wheel, and the left rear wheel. In this case, the wheel speed WS of the right front wheel and the wheel speed WS of the left front wheel are likely to diverge, so that the first wheel speed error DW1, which is the mean square error of the wheel speed WS of the right front wheel and the wheel speed WS of the left front wheel, is likely to become large. Similarly, the wheel speed WS of the right front wheel and the wheel speed WS of the right rear wheel are likely to diverge, so that the third wheel speed error DW3, which is the mean square error of the wheel speed WS of the right front wheel and the wheel speed WS of the right rear wheel, is likely to become large. As a result, the first wheel speed error DW1 and the third wheel speed error DW3 are larger than the second wheel speed error DW2 and the fourth wheel speed error DW4.

[0062] In this regard, in step S35 of the judgment control, the execution unit 210 of the server 200 identifies the top two values ​​among the first wheel speed error DW1, the second wheel speed error DW2, the third wheel speed error DW3, and the fourth wheel speed error DW4. Then, on condition that the acceleration error DG is equal to or greater than the first specified value A1, the execution unit 210 identifies the wheels associated with the top two values ​​identified above among the right front wheel, the left front wheel, the right rear wheel, and the left rear wheel of the vehicle 100 as the wheels most likely to have looseness. This makes it possible to identify the wheels most likely to have looseness.

[0063] (5) In step S53 of the distribution control, the execution unit 210 of the server 200 transmits the determination information IJ to the personal terminal 300. Here, the determination information IJ includes the determination result of step S33 and the identification result of step S35. When the determination information IJ is transmitted from the server 200 in this manner, for example, the user of the vehicle 100 can grasp the determination result, such as whether or not the wheel is loose, contained in the determination information IJ via the display of the personal terminal 300 or the like.

[0064] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0065] In the above embodiment, the collection control may be changed. For example, in the collection control, the motion manager 45 of the vehicle 100 may execute the processes of steps S31 to S35. As a specific example, after step S12, the motion manager 45 may execute the processes of steps S31 to S35 based on the collected data DC generated in step S12. In this configuration, the motion manager 45 may transmit information such as the determination result of step S33 and the identification result of step S35 to the outside of the vehicle 100. In this configuration, the brake ECU 40 corresponds to an information processing device.

[0066] In the above embodiment, the determination control may be changed. For example, the configuration for calculating the estimated lateral acceleration GYE in step S31 may be changed. As a specific example, when the vehicle 100 turns in response to a motion request received by the motion manager 45 from the first support unit 56 or the like, the motion manager 45 receives one or more required values ​​such as a steering angle, a yaw rate, and a turning radius as the motion request from the first support unit 56 or the like. Therefore, in the above situation, the execution unit 210 may calculate the estimated lateral acceleration GYE based on one or more required values ​​such as a steering angle, a yaw rate, and a turning radius.

[0067] For example, the configuration for calculating the acceleration error DG in step S32 may be changed. As a specific example, the execution unit 210 of the server 200 may calculate the absolute value of the difference between the estimated lateral acceleration GYE at the Nth time point and the lateral acceleration GY at the Nth time point as the acceleration error DG. In other words, as long as the acceleration error DG can be calculated as a value indicating the error of the lateral acceleration GY with respect to the estimated lateral acceleration GYE, the configuration for calculating the acceleration error DG may be changed.

[0068] For example, in step S33, the execution unit 210 of the server 200 may always link the newly determined degree of looseness with information on the date and time when the determination was made and store the information in the storage unit 220 each time the execution unit 210 determines the degree of looseness of the wheel. Also, for example, the execution unit 210 of the server 200 may not need to link the newly determined degree of looseness with information on the date and time when the determination was made and store the information in the storage unit 220.

[0069] For example, in step S33, the determination using the second specified value A2 and the third specified value A3 may be omitted. In other words, the execution unit 210 of the server 200 may only determine whether or not the wheels of the vehicle 100 are loose by determining whether or not the acceleration error DG is equal to or greater than the first specified value A1.

[0070] For example, the configuration for calculating the first wheel speed error DW1 in step S34 may be changed. As a specific example, the execution unit 210 of the server 200 may calculate the absolute value of the difference between the wheel speed WS of the right front wheel at the Nth time point and the wheel speed WS of the left front wheel at the Nth time point as the first wheel speed error DW1. In other words, as long as the first wheel speed error DW1 can be calculated as a value indicating the error between the wheel speed WS of the right front wheel and the wheel speed WS of the left front wheel, the configuration for calculating the first wheel speed error DW1 may be changed. As above, the configuration for calculating the second wheel speed error DW2, the third wheel speed error DW3, and the fourth wheel speed error DW4 may be changed.

[0071] For example, in step S34, the error calculated by the execution unit 210 of the server 200 may be changed. As a specific example, the execution unit 210 may calculate the mean square error of the original wheel speed WS with respect to the low-pass filtered value based on the wheel speed WS of the right front wheel of the vehicle 100 acquired over a specified period and the value obtained by applying a low-pass filter to the wheel speed WS of the right front wheel. Similarly to the above, the execution unit 210 may calculate the mean square error of the original wheel speed WS with respect to the value obtained by applying a low-pass filter for the wheel speed WS of the left front wheel, the wheel speed WS of the right rear wheel, and the wheel speed WS of the left rear wheel. In this configuration, in step S35, the execution unit 210 specifies the largest value among the four mean square errors calculated in step S35. Then, the execution unit 210 may specify the wheel related to the largest value specified above as the wheel most likely to have looseness.

[0072] For example, the processes of steps S34 and S35 may be omitted. Even in this case, it is possible to determine whether or not the wheels of the vehicle 100 are loose by executing the process of step S33.

[0073] In the above embodiment, the distribution control may be changed. For example, the execution unit 210 of the server 200 may transmit the judgment information IJ to the vehicle 100. At this time, it is preferable that the motion manager 45 of the vehicle 100 notifies the user of the vehicle 100 of the judgment information IJ via the display 92 or the like. [Explanation of symbols]

[0074] DC...Collected data GX...Longitudinal acceleration GY...Lateral acceleration GYE...Estimated lateral acceleration GZ...Upward acceleration IJ...Judgment information IS...Information processing system NW...Communication network 10...Central ECU 20...Powertrain ECU 30...Steering ECU 40...Brake ECU 45...Motion manager 50...Advanced driving assistance ECU 71...Powertrain device 72...Steering device 73...Brake device 81...Acceleration sensor 82...Wheel speed sensor 83...GNSS receiver 86...Accelerator operation amount sensor 87...Steering angle sensor 88...Brake operation amount sensor 91...DCM 92...Display 100...Vehicle 200...Server 300...Personal terminal

Claims

1. acquiring an actual lateral acceleration, which is an actual measurement value of the lateral acceleration of the vehicle detected by an acceleration sensor mounted on the vehicle, over a predetermined specified period of time; obtaining an estimated lateral acceleration, which is an estimate of the lateral acceleration over the specified period, based on a parameter other than the actual lateral acceleration; calculating an error of the actual lateral acceleration with respect to the estimated lateral acceleration based on the estimated lateral acceleration and the actual lateral acceleration acquired over the specified period; determining that a wheel of the vehicle is loose when the calculated error is equal to or greater than a predetermined value; Run Information processing device.

2. When the specified value is a first specified value, determining that the wheel is in a first state in which no looseness has occurred when the calculated error is less than the first specified value; determining that the wheel is in a second state in which looseness has occurred, when the calculated error is equal to or greater than the first specified value and is less than a second specified value that is a predetermined value greater than the first specified value; determining that the wheel is in a third state in which the degree of looseness of the wheel is greater than that of the second state when the calculated error is equal to or greater than the second specified value; Run The information processing device according to claim 1 .

3. storing the degree of looseness of the wheel each time the degree of looseness of the wheel is determined; If the newly determined degree of looseness is greater than the previously stored degree of looseness, the newly determined degree of looseness is associated with information on the date and time when the determination was made and stored. Run The information processing device according to claim 2 .

4. Transmitting to an external device determination information including a result of determining whether or not looseness has occurred in the wheel; Run The information processing device according to any one of claims 1 to 3.

5. When the error is an acceleration error, obtaining a rotational speed of a right front wheel of the vehicle over the specified period of time; acquiring a rotational speed of a left front wheel of the vehicle over the specified period; obtaining a rotational speed of a right rear wheel of the vehicle over the specified period of time; obtaining a rotational speed of a left rear wheel of the vehicle over the specified period of time; calculating a first wheel speed error, which is an error between the rotation speed of the right front wheel and the rotation speed of the left front wheel, based on the rotation speed of the right front wheel and the rotation speed of the left front wheel acquired over the specified period; calculating a second wheel speed error, which is an error between the rotation speed of the right rear wheel and the rotation speed of the left rear wheel, based on the rotation speed of the right rear wheel and the rotation speed of the left rear wheel acquired over the specified period; calculating a third wheel speed error, which is an error between the rotation speed of the right front wheel and the rotation speed of the right rear wheel, based on the rotation speed of the right front wheel and the rotation speed of the right rear wheel acquired over the specified period; calculating a fourth wheel speed error, which is an error between the rotation speed of the left front wheel and the rotation speed of the left rear wheel, based on the rotation speed of the left front wheel and the rotation speed of the left rear wheel acquired over the specified period; identifying two highest values ​​among the first wheel speed error, the second wheel speed error, the third wheel speed error, and the fourth wheel speed error; Identifying the wheels associated with the identified top two values ​​among the right front wheel, the left front wheel, the right rear wheel, and the left rear wheel as the wheels most likely to have looseness, on condition that the calculated acceleration error is equal to or greater than the specified value; Run The information processing device according to claim 1 .

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