Information processing apparatus

Abstract

The invention relates to an information processing apparatus. The information processing apparatus is configured to acquire an actual lateral acceleration, which is an actual measurement value of a lateral acceleration of a vehicle detected by an acceleration sensor mounted on the vehicle, within a predetermined prescribed period of time. The information processing device is configured to acquire an estimated lateral acceleration, which is an estimated value of the lateral acceleration, within the prescribed period of time based on a parameter different from the actual lateral acceleration. The information processing device is configured to calculate 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 within the prescribed time period. The information processing apparatus is configured to determine that there is wheel looseness in the vehicle under a condition that the calculated error is equal to or greater than a predetermined prescribed value.

Description

Technical Field

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

[0002] Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2018-506470 (JP 2018-506470A) discloses a method for detecting that a wheel is not properly fixed to an axle of a vehicle (i.e., detecting wheel looseness). In the wheel looseness detection method of JP2018-506470 A, a wheel speed signal indicating the rotation speed of a wheel of the vehicle is acquired within a certain period of time. In the wheel looseness detection method, a correction signal is calculated by correcting the acquired wheel speed signal. In the wheel looseness detection method, a low-pass filtered signal is also calculated by low-pass filtering the calculated correction signal. In the wheel looseness detection method, an error of the correction signal relative to the low-pass filtered signal is then calculated based on the correction signal and the low-pass filtered signal. In the wheel looseness detection method, whether there is wheel looseness is determined based on the calculated error. Summary of the invention

[0003] In the wheel looseness detection method of JP 2018-506470 A, whether or not there is wheel looseness in the vehicle is determined based on the rotation speed of the wheel. However, JP 2018-506470 A does not focus on determining wheel looseness based on parameters other than the rotation speed of the wheel.

[0004] The scheme of the present disclosure provides an information processing device. The information processing device is configured to: obtain an actual lateral acceleration within a predetermined prescribed time period, the actual lateral acceleration being an actual measured value of the lateral acceleration of the vehicle detected by an acceleration sensor installed on the vehicle; obtain an estimated lateral acceleration within the prescribed time period based on a parameter different from the actual lateral acceleration, the estimated lateral acceleration being an estimated value of the lateral acceleration; calculate an error of the actual lateral acceleration relative to the estimated lateral acceleration based on the estimated lateral acceleration and the actual lateral acceleration obtained within the prescribed time period; and determine that there is wheel looseness in the vehicle under the condition that the calculated error is equal to or greater than a predetermined prescribed value.

[0005] According to the above configuration, it is possible to determine whether there is wheel looseness based on the error of the actual lateral acceleration relative to the estimated lateral acceleration. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, wherein like symbols represent like elements, and wherein:

[0007] Figure 1is a schematic configuration diagram of an information processing system;

[0008] Figure 2 is a functional block diagram showing a basic configuration of a motion manager; and

[0009] Figure 3 It is a sequence diagram showing collection control, determination control, and distribution control. DETAILED DESCRIPTION

[0010] Schematic configuration of information processing system

[0011] The following will refer to Figures 1 to 3 Embodiments of the present invention are described. First, a schematic configuration of an information processing system IS will be described.

[0012] like Figure 1 As shown, the information processing system IS includes a plurality of vehicles 100. An example of the vehicle 100 is a common four-wheeled motor vehicle. 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. Figure 1 Only one vehicle 100 is shown representatively.

[0013] The vehicle 100 includes a power transmission device 71 , a steering system 72 , and a braking device 73 .

[0014] The power transmission device 71 includes an engine, a motor generator, and a transmission. The engine can apply driving force to the driving wheels of the vehicle 100 via the transmission. The motor generator can apply driving force to the driving wheels of the vehicle 100 via the transmission.

[0015] An example of the steering system 72 is a rack and pinion electric steering device. The steering system 72 can change the direction of the steering wheels of the vehicle 100 by controlling a rack and pinion (not shown).

[0016] The brake device 73 is a so-called mechanical brake device for mechanically braking the wheels of the vehicle 100. In the present embodiment, an example of the brake device 73 is a disk brake.

[0017] like Figure 1 As shown, 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. The term "ECU" is an abbreviation of "electronic control unit".

[0018] 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 central processing unit (CPU). The storage device 12 includes a read-only memory (ROM) that can only be read, a volatile random access memory (RAM) that can be read and written, and a non-volatile memory that can be read and written. The storage device 12 stores various programs and various types of data in advance. The execution device 11 implements various processes by executing the programs stored in the storage device 12.

[0019] The powertrain ECU 20 can communicate with the central ECU 10 via the 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 memory. The storage device 22 pre-stores various programs and various types of data. The storage device 22 also pre-stores a powertrain application 23A as one of the various programs. The powertrain application 23A is application software for controlling the powertrain device 71. The execution device 21 realizes a function as a powertrain control unit 23 to be described later by executing the powertrain application 23A stored in the storage device 22.

[0020] The steering ECU 30 can communicate with the central ECU 10 via the second external bus 62. The steering ECU 30 controls the steering system 72 by outputting a control signal to the steering system 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 memory. The storage device 32 pre-stores various programs and various types of data. The storage device 32 also pre-stores a steering application 33A as one of the various programs. The steering application 33A is application software for controlling the steering system 72. The execution device 31 realizes a function as a steering control unit 33 to be described later by executing the steering application 33A stored in the storage device 32.

[0021] 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 memory. The storage device 42 pre-stores various programs and various types of data. The storage device 42 also pre-stores a brake application 43A as one of the various programs. The brake application 43A is an application software for controlling the brake device 73. The storage device 42 also pre-stores a motion manager application 45A as one of the various programs. The motion manager application 45A is an application software for mediating multiple motion requests. The execution device 41 realizes a function as a brake control unit 43 to be described later by executing the brake application 43A stored in the storage device 42. The execution device 41 also realizes a function as a motion manager 45 to be described later by executing the motion manager application 45A stored in the storage device 42.

[0022] The advanced driving assistance ECU 50 can communicate with the central ECU 10 via the fourth external bus 64. The advanced driving assistance ECU 50 performs various types of driving assistance. 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 memory. The storage device 52 stores various programs and various types of data in advance. The various programs include a first assistance application 56A, a second assistance application 57A, and a third assistance application 58A. An example of the first assistance application 56A is an application software for collision damage mitigation braking (i.e., so-called autonomous emergency braking (AEB)) for automatically applying brakes to mitigate collision damage to the vehicle 100. An example of the second assistance application 57A is an application software for so-called lane keeping assist (LKA) for keeping the vehicle 100 in its lane. An example of the third assistance application 58A is an application software for so-called adaptive cruise control (ACC), which allows the vehicle 100 to travel while maintaining a constant following distance with a leading vehicle traveling in front of the vehicle 100. In the present embodiment, the first assistance application 56A, the second assistance application 57A, and the third assistance application 58A are each application software that realizes the driving assistance function of the vehicle 100. The execution device 51 realizes the function as the first assistance unit 56 to be described later by executing the first assistance application 56A stored in the storage device 52. The execution device 51 also realizes the function as the second assistance unit 57 to be described later by executing the second assistance application 57A stored in the storage device 52. The execution device 51 also realizes the function as the third assistance unit 58 to be described later by executing the third assistance application 58A stored in the storage device 52.

[0023] like Figure 1 As shown, 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.

[0024] 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 the acceleration along the longitudinal axis of the vehicle 100. The lateral acceleration GY is the acceleration along the lateral axis of the vehicle 100. The vertical acceleration GZ is the acceleration along the vertical axis of the vehicle 100. In the present embodiment, the lateral acceleration GY is an actual measurement value of the lateral acceleration of the vehicle 100 detected by the acceleration sensor 81, that is, the actual lateral acceleration.

[0025] The wheel speed sensor 82 detects the 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 the present embodiment, the vehicle 100 includes four wheel speed sensors 82 for the four wheels of the vehicle 100. Figure 1 Only one wheel speed sensor 82 is representatively shown.

[0026] The GNSS receiver 83 detects position coordinates PC, that is, coordinates of a location where the vehicle 100 is located, by communicating with a GNSS satellite (not shown). The term "GNSS" is an abbreviation of "Global Navigation Satellite System".

[0027] The accelerator operation amount sensor 86 detects the accelerator operation amount ACC, that is, the operation amount of the accelerator pedal operated by the driver. The steering angle sensor 87 detects the steering angle SA, that is, the angular position of the steering wheel operated by the driver. The brake operation amount sensor 88 detects the brake operation amount BRA, that is, the operation amount of the brake pedal operated by the driver.

[0028] The powertrain ECU 20 acquires a signal indicating the accelerator operation amount ACC from the accelerator operation amount sensor 86. The steering ECU 30 acquires a signal indicating the steering angle SA from the steering angle sensor 87. The brake ECU 40 acquires a signal indicating the longitudinal acceleration GX, the lateral acceleration GY, and the vertical acceleration GZ from the acceleration sensor 81. The brake ECU 40 also acquires a signal indicating the position coordinate PC from the GNSS receiver 83. The brake ECU 40 also acquires a signal indicating the four wheel speeds WS from the four wheel speed sensors 82. The brake ECU 40 acquires a signal indicating the brake operation amount BRA from the brake operation amount sensor 88. The brake ECU 40 can acquire various values ​​including the accelerator operation amount ACC and the steering angle SA via the central ECU 10.

[0029] The brake ECU 40 calculates the vehicle speed SP, that 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 can acquire the vehicle speed SP.

[0030] like Figure 1 As shown, the vehicle 100 includes a DCM 91 and a display 92. The DCM 91 is connected to the central ECU 10 via the fifth external bus 65. The DCM 91 can wirelessly communicate with a device outside the vehicle 100 via a communication network NW. The term "DCM" is an abbreviation of "Data Communication Module". The display 92 is connected to the central ECU 10. The display 92 can display various types of information based on image data output from the central ECU 10.

[0031] like Figure 1 As shown, the information processing system IS includes a server 200. The server 200 includes an execution unit 210, a storage unit 220, and a communication unit 230. The communication unit 230 can communicate with a device outside the server 200 via a communication network NW. The storage unit 220 includes a ROM, a RAM, and a memory. The storage unit 220 stores various programs and various types of data in advance. An example of the execution unit 210 is a CPU. The execution unit 210 implements various processes by executing various programs stored in the storage unit 220. In the present embodiment, the server 200 is an example of an information processing device.

[0032] like Figure 1 As shown, the information processing system IS includes a plurality of personal terminals 300. An example of the personal terminal 300 is a mobile terminal owned by a user of the vehicle 100, namely, a so-called smartphone. Figure 1Only one personal terminal 300 is representatively shown in the figure. 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 a device outside the personal terminal 300 via a communication network NW. The storage unit 320 includes a ROM, a RAM, and a memory. The storage unit 320 stores various programs and various types of data in advance. An example of the execution unit 310 is a CPU. The execution unit 310 implements various processes by executing various programs stored in the storage unit 320.

[0033] Basic configuration related to motion manager

[0034] Next, we will refer to Figure 2 Describes the basic configuration related to the motion manager 45. Figure 2 As shown, the motion manager 45 can communicate with the first auxiliary unit 56, the second auxiliary unit 57, and the third auxiliary unit 58. The motion manager 45 can also communicate with the powertrain control unit 23, the steering control unit 33, and the brake control unit 43.

[0035] The first auxiliary unit 56, the second auxiliary unit 57, and the third auxiliary unit 58 output motion requests to the motion manager 45 when performing various types of control. At this time, for example, the first auxiliary unit 56, the second auxiliary unit 57, and the third auxiliary unit 58 continuously output motion requests from when various types of control become necessary until such control is no longer necessary. The motion request includes a request longitudinal acceleration GXR for controlling the acceleration along the longitudinal axis of the vehicle 100.

[0036] The motion manager 45 receives the request longitudinal acceleration GXR as the motion request from the first auxiliary unit 56, the second auxiliary unit 57 and the third auxiliary unit 58. The motion manager 45 mediates the received request longitudinal acceleration GXR. For example, when the motion manager 45 receives the request longitudinal acceleration GXR from a plurality of auxiliary units, the motion manager 45 selects the earliest received request longitudinal acceleration GXR as the mediation result. Alternatively, for example, when the motion manager 45 receives the request longitudinal acceleration GXR from a plurality of auxiliary units, the motion manager 45 selects the minimum request longitudinal acceleration GXR as the mediation result. Therefore, the motion manager 45 mediates the motion request according to a predetermined rule based on the driving condition of the vehicle 100.

[0037] The motion manager 45 generates an indication signal for controlling an action request of various actuators based on the requested longitudinal acceleration GXR selected as a result of the mediation. The various actuators include a power transmission device 71, a steering system 72, and a braking device 73. For example, when controlling the power transmission device 71, the motion manager 45 outputs an indication signal for an action request to the power transmission control unit 23. The power transmission control unit 23 then outputs a control signal to the power transmission device 71 based on the indication signal for the action request. In this way, the indication signal output from 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.

[0038] In addition to the indication signal for the motion request from the motion manager 45, each of the powertrain control unit 23, the steering control unit 33, and the brake control unit 43 may receive an indication signal for the motion request from the driver of the vehicle 100. When each of the powertrain control unit 23, the steering control unit 33, and the brake control unit 43 receives the indication signal for the motion request from the driver of the vehicle 100, each of the powertrain control unit 23, the steering control unit 33, and the brake control unit 43 outputs a control signal to its corresponding actuator based on the indication signal for the motion request from the driver of the vehicle 100. That is, when each control unit receives the indication signal for the motion request from the driver of the vehicle 100, each control unit disables the indication signal for the motion request from the motion manager 45. The powertrain control unit 23 may receive the accelerator operation amount ACC from the accelerator operation amount sensor 86 as an indication signal for the motion request to control the actuator based on the driver's operation. The steering control unit 33 may receive the steering angle SA from the steering angle sensor 87 as an indication signal for the motion request to control the actuator based on the driver's operation. The brake control unit 43 may receive the brake operation amount BRA from the brake operation amount sensor 88 as an instruction signal for an actuation request to control the actuator based on the driver's operation.

[0039] Collection Control

[0040] Next, we will refer to Figure 3 The collection control performed by the vehicle 100 and the server 200 is described. The collection control is a control in which the server 200 collects various values ​​from the vehicle 100. The collection control is performed in parallel between a plurality of vehicles 100 and a single server 200. In the present embodiment, the motion manager 45 of the vehicle 100 performs the collection control at each predetermined control cycle.

[0041] like Figure 3As shown, when the collection control starts, the motion manager 45 of the vehicle 100 executes step S11. In step S11, the motion manager 45 determines whether a predetermined precondition is satisfied. In this embodiment, the motion manager 45 determines that the precondition is satisfied when all of the following requirements (1) to (4) are satisfied.

[0042] Requirement (1): All sensors and ECUs are normal.

[0043] Requirement (2): The amount of change in the vehicle speed SP per unit time is equal to or smaller than a predetermined reference amount of change.

[0044] Requirement (3): The amount of change in the steering angle SA per unit time is equal to or smaller than a predetermined specific amount of change.

[0045] Requirement (4): The vehicle speed SP is within a predetermined reference speed range.

[0046] The reference speed range is determined in advance as a range of vehicle speed SP for ensuring determination accuracy in determination control to be described later by experiments, simulations, etc. An example of the reference speed range is approximately a dozen kilometers per hour to approximately several tens of kilometers per hour.

[0047] When the movement manager 45 determines in step S11 that the precondition is not satisfied, the movement manager 45 ends the current collection control. On the other hand, when the movement manager 45 determines in step S11 that the precondition is satisfied, the process proceeds to step S12.

[0048] In step S12, the motion manager 45 generates collected data DC. In the present embodiment, the motion manager 45 generates data including vehicle speed SP, steering angle SA, lateral acceleration GY and four wheel speeds WS as collected data DC. After step S12, the process proceeds to step S13.

[0049] 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. As the collection control is repeatedly executed, the execution unit 210 of the server 200 can acquire the collected data DC transmitted from each vehicle 100 in time sequence. After step S13, the execution unit 210 of the server 200 ends the current collection control.

[0050] Decision Control

[0051] Next, we will refer to Figure 3Described is the determination control performed by the server 200. The determination control is a control for determining whether there is a loose wheel in the vehicle 100. In the present embodiment, the execution unit 210 of the server 200 executes the determination control under the condition that the execution unit 210 has successfully acquired the collected data DC continuously from the same vehicle 100 within a predetermined prescribed time period. An example of the prescribed time period is about several seconds to about ten seconds.

[0052] like Figure 3 As shown, when it is determined that the control starts, the execution unit 210 of the server 200 executes step S31. In step S31, the execution unit 210 obtains the lateral acceleration GY of the prescribed time period from the collected data DC of the prescribed time period. In this embodiment, when the vehicle 100 is turning left, the lateral acceleration GY takes a positive value. On the other hand, when the vehicle 100 is turning right, the lateral acceleration GY takes a negative value.

[0053] The execution unit 210 also obtains the steering angle SA and the vehicle speed SP of the prescribed time period from the collected data DC of the prescribed time period. The execution unit 210 then calculates the estimated lateral acceleration GYE, that is, the estimated value of the lateral acceleration of the vehicle 100, based on the steering angle SA and the vehicle speed SP. For example, when the steering angle SA is the angle at which the vehicle 100 is turning left, the estimated lateral acceleration GYE has a positive value. On the other hand, when the steering angle SA is the angle at which the vehicle 100 is turning right, the estimated lateral acceleration GYE has a negative value. The execution unit 210 calculates the estimated lateral acceleration GYE within the prescribed time period. In the present embodiment, the estimated lateral acceleration GYE is an estimated value of the lateral acceleration of the vehicle 100 obtained based on the steering angle SA and the vehicle speed SP, which are parameters different from the lateral acceleration GY.

[0054] The execution unit 210 also obtains four wheel speeds WS of the prescribed time period from the collected data DC of the prescribed time period. In other words, the execution unit 210 obtains 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 within the prescribed time period. After step S31, the process proceeds to step S32.

[0055] In step S32, the execution unit 210 calculates the acceleration error DG, i.e., the mean square error of the lateral acceleration GY relative to the estimated lateral acceleration GYE, based on the estimated lateral acceleration GYE and the lateral acceleration GY acquired within the prescribed time period. As described above, the collected data DC is acquired in each predetermined control cycle. Therefore, as the values ​​acquired in each predetermined control cycle, there are multiple estimated lateral accelerations GYE and multiple lateral accelerations GY of the prescribed time period. In the following description, it is assumed that each of the estimated lateral acceleration GYE and the lateral acceleration GY of the prescribed time period has N data. Note that "N" is an integer greater than 2. The N data are composed of data at the first time point, data at the second time point, ..., and data at the Nth time point in chronological order, wherein the data at the first time point is the earliest. In step S32, the execution unit 210 calculates the square of the difference between the estimated lateral acceleration GYE at the first time point and the lateral acceleration GY at the first time point. The execution unit 210 also calculates the square of the difference between the estimated lateral acceleration GYE at the second time point and the lateral acceleration GY at the second time point. Similarly, the execution unit 210 calculates the square of the difference between the estimated lateral acceleration GYE and the lateral acceleration GY for each of the third to Nth time points. Then, the execution unit 210 calculates the average value of the N values ​​calculated as described above as the acceleration error DG. In the present embodiment, the acceleration error DG is an example of the error of the lateral acceleration GY relative to the estimated lateral acceleration GYE. After step S32, the process proceeds to step S33.

[0056] In step S33, the execution unit 210 determines the degree of looseness of the wheels of the vehicle 100 according to the acceleration error DG. Specifically, the execution unit 210 determines the degree of looseness of the wheels as follows. The execution unit 210 uses a predetermined first prescribed value A1, a predetermined second prescribed value A2, and a predetermined third prescribed value A3. The second prescribed value A2 is greater than the first prescribed value A1. The third prescribed value A3 is greater than the second prescribed value A2. The first prescribed value A1, the second prescribed value A2, and the third prescribed value A3 are predetermined as thresholds for determining the degree of looseness of the wheels through experiments, simulations, etc.

[0057] When the acceleration error DG is less than the first prescribed value A1, the execution unit 210 determines that the vehicle 100 is in a first state where there is no loose wheel. When the acceleration error DG is equal to or greater than the first prescribed value A1 and less than the second prescribed value A2, the execution unit 210 determines that the vehicle 100 is in a second state where there is loose wheel. When the acceleration error DG is equal to or greater than the second prescribed value A2 and less than the third prescribed value A3, the execution unit 210 determines that the vehicle 100 is in a third state where there is loose wheel. The third state is a state where the degree of loose wheel is greater than the second state. When the acceleration error DG is equal to or greater than the third prescribed value A3, the execution unit 210 determines that the vehicle 100 is in a fourth state where there is loose wheel. The fourth state is a state where the degree of loose wheel is greater than the third state. As described above, when the acceleration error DG is less than the first prescribed value A1, the execution unit 210 determines that there is no loose wheel. When the acceleration error DG is equal to or greater than the first prescribed value A1, the execution unit 210 determines that there is loose wheel.

[0058] Whenever the execution unit 210 determines the degree of wheel looseness, the execution unit 210 stores the determined degree of wheel looseness in the storage unit 220. In addition, when the newly determined degree of wheel looseness is greater than the degree of past wheel looseness stored in the storage unit 220, the execution unit 210 stores the newly determined degree of wheel looseness in the storage unit 220 in association with information about the date and time when the determination is made. For example, it is assumed here that the maximum value of the degree of past wheel looseness stored in the storage unit 220 is the second state. In this case, when the execution unit 210 determines in step S33 that the degree of wheel looseness is the third state or the fourth state, the execution unit 210 stores the newly determined degree of wheel looseness in the storage unit 220 in association with information about the date and time when the determination is made. After step S33, the process proceeds to step S34.

[0059] In step S34, the execution unit 210 calculates the first wheel speed error DW1, that is, the mean square error between the wheel speed WS of the right front wheel and the wheel speed WS of the left front wheel, based on the wheel speed WS of the right front wheel and the wheel speed WS of the left front wheel of the vehicle 100 acquired within the prescribed time period. Specifically, the execution unit 210 calculates the square of the difference between the wheel speed WS of the right front wheel at the first time point and the wheel speed WS of the left front wheel at the first time point. The execution unit 210 also calculates the square of the difference between the wheel speed WS of the right front wheel at the second time point and the wheel speed WS of the left front wheel at the second time point. Similarly, the execution unit 210 calculates the square of the difference between the wheel speed WS of the right front wheel and the wheel speed WS of the left front wheel for each of the third to Nth time points. The execution unit 210 then calculates the average value of the N values ​​calculated as described above as the first wheel speed error DW1. In the present embodiment, the first wheel speed error DW1 is an example of the error between the wheel speed WS of the right front wheel and the wheel speed WS of the left front wheel.

[0060] The execution unit 210 similarly calculates the second wheel speed error DW2, i.e., the 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 within the prescribed time period. In the present embodiment, the second wheel speed error DW2 is an example of the error between the wheel speed WS of the right rear wheel and the wheel speed WS of the left rear wheel. The execution unit 210 also calculates the third wheel speed error DW3, i.e., the 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 within the prescribed time period. In the present embodiment, the third wheel speed error DW3 is an example of the error between the wheel speed WS of the right front wheel and the wheel speed WS of the right rear wheel. The execution unit 210 also calculates a fourth wheel speed error DW4, i.e., 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 within a prescribed period of time. In the present 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 process proceeds to step S35.

[0061] In step S35, the execution unit 210 identifies the wheel of the vehicle 100 that is most likely to be loose 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 two maximum 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. As used herein, "maximum" means the maximum value. Under the condition that the acceleration error DG is equal to or greater than the first prescribed value A1, the execution unit 210 then identifies the wheel associated with the two identified maximum values ​​among the right front wheel, the left front wheel, the right rear wheel, and the left rear wheel of the vehicle 100 as the wheel that is most likely to be loose. For example, it is assumed here that the two identified maximum values ​​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 both when calculating the first wheel speed error DW1 and when calculating the third wheel speed error DW3. Therefore, in this example, the execution unit 210 identifies the right front wheel, which is the wheel associated with the two identified maximum values, as the wheel most likely to be loose. When there is no wheel associated with the two identified maximum values, the execution unit 210 determines that the loose wheel is not identifiable. After step S35, the execution unit 210 ends the current determination control.

[0062] Distribution Control

[0063] Next, we will refer to Figure 3 The distribution control performed by the personal terminal 300 and the server 200 is described. The distribution 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 distribution control is performed in parallel between a plurality of personal terminals 300 and a single server 200. Each vehicle 100 and the personal terminal 300 of the vehicle 100 are associated with each other in advance. In the present embodiment, whenever the user of the vehicle 100 requests execution of the distribution control by operating the personal terminal 300, the execution unit 310 of the personal terminal 300 executes the distribution control.

[0064] like Figure 3 As shown, when the distribution control starts, the execution unit 310 of the personal terminal 300 executes step S51. In step S51, the execution unit 310 of the personal terminal 300 sends a request signal for requesting the server 200 to send the determination information IJ. When the execution unit 210 of the server 200 receives the request signal, the process proceeds to step S52.

[0065] 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 in step S33 and the recognition result in step S35 as determination information IJ. That is, the determination information IJ includes the determination result as to whether there is a loose wheel in the vehicle 100. After step S52, the process proceeds to step S53.

[0066] 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 the display of the personal terminal 300 or the like. After step S53, the execution unit 310 of the personal terminal 300 ends the current distribution control.

[0067] Effect of the embodiment

[0068] For example, it is assumed herein that nuts for fixing wheels to wheel hubs have become loose in the vehicle 100. When the vehicle 100 has such a loose wheel, the behavior of the vehicle 100 tends to be disturbed during the travel of the vehicle 100. Therefore, 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., more often deviates 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, i.e., the mean square error of the lateral acceleration GY with respect to the estimated lateral acceleration GYE, increases due to the loose wheel of the vehicle 100.

[0069] Effects of the Embodiments

[0070] (1) In step S32 of the determination control, the execution unit 210 of the server 200 calculates the acceleration error DG, i.e., the mean square error of the lateral acceleration GY relative to the estimated lateral acceleration GYE, based on the estimated lateral acceleration GYE and the lateral acceleration GY acquired within the prescribed time period. In step S33, when the acceleration error DG is equal to or greater than the first prescribed value A1, the execution unit 210 determines that there is wheel looseness in the vehicle 100. Therefore, it is possible to determine whether there is wheel looseness based on the acceleration error DG.

[0071] (2) In step S33 of the determination control, the execution unit 210 of the server 200 determines the degree of wheel looseness 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 determines that the vehicle 100 is in a first state where there is no wheel looseness. 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 vehicle 100 is in a second state where there is wheel looseness. 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 determines that the vehicle 100 is in a third state where the degree of wheel looseness is greater than the second state. When the acceleration error DG is equal to or greater than the third specified value A3, the execution unit 210 determines that the vehicle 100 is in a fourth state where the degree of wheel looseness is greater than the third state. Therefore, the degree of wheel looseness is determined in more than three stages, rather than in two stages (i.e., whether looseness has occurred or has not yet occurred). Therefore, a more accurate and convenient determination result can be obtained.

[0072] (3) In step S33 of the determination control, each time the execution unit 210 of the server 200 determines the degree of wheel looseness, the execution unit 210 stores the determined degree of wheel looseness in the storage unit 220. In addition, when the newly determined degree of wheel looseness is greater than the past degree of wheel looseness stored in the storage unit 220, the execution unit 210 stores the newly determined degree of wheel looseness in the storage unit 220 in association with information about the date and time when the determination is made. Therefore, when the degree of wheel looseness increases, information about the date and time when the increase occurs is stored in the storage unit 220. Therefore, it is possible to identify, for example, the time to perform maintenance on the vehicle 100 based on the information about the date and time when the degree of wheel looseness increases.

[0073] (4) For example, it is assumed herein that the right front wheel has become loose among the right front wheel, the left front wheel, the right rear wheel and the left rear wheel of the vehicle 100. In this case, there is a deviation between the wheel speed WS of the right front wheel and the wheel speed WS of the left front wheel. Therefore, the first wheel speed error DW1, i.e., the mean square error between the wheel speed WS of the right front wheel and the wheel speed WS of the left front wheel, tends to become larger. Similarly, there is a deviation between the wheel speed WS of the right front wheel and the wheel speed WS of the right rear wheel. Therefore, the third wheel speed error DW3, i.e., the mean square error between the wheel speed WS of the right front wheel and the wheel speed WS of the right rear wheel, tends to become larger. As a result, the first wheel speed error DW1 and the third wheel speed error DW3 become larger than the second wheel speed error DW2 and the fourth wheel speed error DW4.

[0074] In this regard, in step S35 of the determination control, the execution unit 210 of the server 200 identifies two maximum 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. Under the condition that the acceleration error DG is equal to or greater than the first prescribed value A1, the execution unit 210 then identifies the wheel associated with the identified two maximum values ​​among the right front wheel, the left front wheel, the right rear wheel, and the left rear wheel of the vehicle 100 as the wheel most likely to be loose. Therefore, the wheel most likely to be loose can be identified.

[0075] (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. The determination information IJ includes the determination result in step S33 and the recognition result in step S35. When the determination information IJ is thus transmitted from the server 200, for example, the user of the vehicle 100 can grasp the determination result (i.e., the determination result as to whether there is loose wheel, etc.) included in the determination information IJ via the display of the personal terminal 300, etc.

[0076] Variations

[0077] The above-described embodiment can be modified as follows. The above-described embodiment and the following modified examples can be combined as long as no technical contradiction occurs.

[0078] - In the above embodiments, the collection control may be modified.

[0079] For example, in the collection control, the motion manager 45 of the vehicle 100 may perform steps S31 to S35. As a specific example, the motion manager 45 may perform steps S31 to S35 after step S12 based on the collection data DC generated in step S12. In this configuration, the motion manager 45 may transmit information such as the determination result in step S33 and the recognition result in step S35 to the outside of the vehicle 100. In the present embodiment, the brake ECU 40 is an information processing device.

[0080] - In the above-described embodiments, the decision control may be modified.

[0081] For example, the configuration for calculating the estimated lateral acceleration GYE in step S31 may be modified. As a specific example, when the vehicle 100 turns in response to a motion request received by the motion manager 45 from the first auxiliary unit 56 or the like, the motion manager 45 receives one or more request values ​​such as a steering angle, a yaw rate, and a turning radius as a motion request from the first auxiliary unit 56 or the like. Therefore, in the above case, the execution unit 210 may calculate the estimated lateral acceleration GYE based on one or more request values ​​such as a steering angle, a yaw rate, and a turning radius.

[0082] - For example, the configuration for calculating the acceleration error DG in step S32 may be modified. 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. That is, the configuration for calculating the acceleration error DG may be modified as long as the acceleration error DG can be calculated as a value indicating the error of the lateral acceleration GY relative to the estimated lateral acceleration GYE.

[0083] - For example, in step S33, each time the execution unit 210 of the server 200 determines the degree of wheel looseness, the execution unit 210 may always store the newly determined degree of wheel looseness in association with the information on the date and time when the determination is made in the storage unit 220. Alternatively, for example, the execution unit 210 of the server 200 may not store the newly determined degree of wheel looseness in association with the information on the date and time when the determination is made in the storage unit 220.

[0084] - For example, in step S33, the determination using the second and third prescribed values ​​A2 and A3 may be omitted. In other words, the execution unit 210 of the server 200 may determine whether there is wheel looseness in the vehicle 100 only by determining whether the acceleration error DG is equal to or greater than the first prescribed value A1.

[0085] - For example, the configuration for calculating the first wheel speed error DW1 in step S34 may be modified. 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. That is, the configuration for calculating the first wheel speed error DW1 may be modified 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 second wheel speed error DW2, the third wheel speed error DW3, and the fourth wheel speed error DW4 may be modified in a similar manner to that described above.

[0086] -For example, the error calculated by the execution unit 210 of the server 200 in step S34 may be modified. As a specific example, the execution unit 210 may calculate the mean square error of the original wheel speed WS relative to the low-pass filtered value based on the wheel speed WS of the right front wheel of the vehicle 100 acquired within a prescribed time period and the low-pass filtered value obtained by low-pass filtering the wheel speed WS of the right front wheel. Similarly, the execution unit 210 may calculate the mean square error of the original wheel speed WS relative to the low-pass filtered value for each of 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 identifies the maximum value of the four mean square errors calculated in step S34. The execution unit 210 then identifies the wheel associated with the identified maximum value as the wheel most likely to be loose.

[0087] - For example, steps S34 and S35 may be omitted. Even in this case, it is possible to determine whether there is loose wheel in the vehicle 100 by executing step S33.

[0088] - In the above embodiments, the distribution control may be modified.

[0089] For example, the execution unit 210 of the server 200 may transmit the determination information IJ to the vehicle 100. At this time, the motion manager 45 of the vehicle 100 preferably notifies the user of the vehicle 100 of the determination information IJ via the display 92 or the like.

Claims

1. An information processing device, configured to: acquiring an actual lateral acceleration within a predetermined prescribed time period, the actual lateral acceleration being an actual measured value of the lateral acceleration of the vehicle detected by an acceleration sensor mounted on the vehicle, acquiring an estimated lateral acceleration within the prescribed period of time based on a parameter different from the actual lateral acceleration, the estimated lateral acceleration being an estimated value of the lateral acceleration, calculating 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 within the prescribed period of time, and Under the condition that the calculated error is equal to or greater than a predetermined specified value, it is determined that there is wheel looseness in the vehicle.

2. The information processing device according to claim 1, characterized in that When the prescribed value is a first prescribed value, the information processing device is configured to: Under the condition that the calculated error is less than the first specified value, it is determined that the vehicle is in a first state where no wheel is loose, Under the condition that the calculated error is equal to or greater than the first prescribed value and less than a predetermined second prescribed value, it is determined that the vehicle is in a second state where the wheel is loose, the second prescribed value being a value greater than the first prescribed value, and Under the condition that the calculated error is equal to or greater than the second prescribed value, it is determined that the vehicle is in a third state in which the degree of wheel looseness is greater than that of the second state.

3. The information processing device according to claim 2, characterized in that: The information processing device is configured to: Each time the information processing device determines the degree of looseness of the wheel, the degree of looseness of the wheel is stored, and Under the condition that the newly determined degree of wheel looseness is greater than the stored past degree of wheel looseness, the newly determined degree of wheel looseness is stored in association with information on the date and time of making the determination of the newly determined degree of wheel looseness.

4. The information processing device according to any one of claims 1 to 3, characterized in that: The information processing device is configured to transmit determination information to the outside, the determination information including a determination result as to whether there is wheel looseness.

5. The information processing device according to claim 1, characterized in that When the error is an acceleration error, the information processing device is configured to: obtaining the rotation speed of the right front wheel of the vehicle within the specified time period, obtaining the rotation speed of the left front wheel of the vehicle within the specified time period, obtaining the rotation speed of the right rear wheel of the vehicle within the specified time period, obtaining the rotation speed of the left rear wheel of the vehicle within the specified time period, calculating a first wheel speed error as 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 within the prescribed period of time, calculating a second wheel speed error as 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 within the prescribed period of time, calculating a third wheel speed error as 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 within the prescribed period of time, calculating a fourth wheel speed error as 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 within the prescribed period of time, identifying two maximum values ​​of the first wheel speed error, the second wheel speed error, the third wheel speed error, and the fourth wheel speed error that have been calculated, and Under the condition that the calculated acceleration error is equal to or greater than the prescribed value, the wheel associated with the two identified maximum values ​​among the right front wheel, the left front wheel, the right rear wheel and the left rear wheel is identified as the wheel most likely to be loose.

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