Determination device

Abstract

To provide a technique by which prediction accuracy of a sign of anomaly of a vehicle underbody component is improved.SOLUTION: A determination device determines the presence / absence of a sign of anomaly of a vehicle underbody component, in which one or more processors acquire the tire forces of left and right wheels on at least one side of the front and rear sides of the vehicle, or the tire forces of front and rear wheels on at least one side of the left and right sides of the vehicle. The device determines the presence / absence of a sign of anomaly of a vehicle underbody component based on the acquired tire forces.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a determination device, and more particularly to a determination device that determines whether or not there is a sign of an abnormality in a suspension component of a vehicle. [Background technology]

[0002] BACKGROUND ART Conventionally, techniques for determining whether or not there is an abnormality in a suspension part such as a wheel of a vehicle have been known.

[0003] Patent Document 1 discloses a tire condition estimation device that includes a wheel speed sensor that detects wheel speed, which is the angular velocity of the wheels, and outputs a wheel speed signal corresponding to the wheel speed; a vehicle state quantity detection device that detects state quantities such as vehicle tire pressure and outputs a vehicle state quantity signal corresponding to the detected state quantities; and an estimator that estimates the tire condition based on the wheel speed signal output from the wheel speed sensor, and that performs normalization processing to normalize the tire condition estimate using the wheel speed signal based on the vehicle state quantity signal output from the vehicle state quantity detection device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-248915 Summary of the Invention [Problem to be solved by the invention]

[0005] According to the technology disclosed in Patent Document 1, the presence or absence of a tire pressure abnormality is determined using state quantities such as tire pressure indirectly estimated based on wheel speed signals that represent the angular velocity of the wheels. However, there are various other abnormalities in vehicle suspension components in addition to tire pressure abnormalities, and the conventional technology has room for improvement in terms of accurately predicting the signs of these abnormalities.

[0006] In view of the above circumstances, an object of the present disclosure is to provide a technology that improves the accuracy of predicting signs of abnormalities in vehicle suspension components. [Means for solving the problem]

[0007] A determination device according to one embodiment of the present disclosure is a determination device that determines whether or not there are signs of an abnormality in a vehicle's suspension parts, and includes one or more processors and one or more memories communicatively connected to the one or more processors, wherein the one or more processors acquire tire forces of the left and right wheels on at least one of the front and rear sides of the vehicle, or tire forces of the front and rear wheels on at least one of the left and right sides of the vehicle, and determines whether or not there are signs of an abnormality in the vehicle's suspension parts based on the acquired tire forces. [Effects of the Invention]

[0008] According to an embodiment of the present disclosure, it is possible to improve the accuracy of predicting signs of abnormalities in vehicle suspension components. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram illustrating an example configuration of a vehicle equipped with a determination device according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a block diagram illustrating an example configuration of a determination device according to an embodiment of the present disclosure. [Figure 3] 10 is a flowchart illustrating an example of operation of a determination device according to an embodiment of the present disclosure. [Figure 4] 10 is a flowchart illustrating an example of operation of a determination device according to an embodiment of the present disclosure. [Figure 5] 10 is a flowchart illustrating an example of operation of a determination device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0011] (1. Overall vehicle configuration) An example of the overall configuration of a vehicle 1 equipped with a determination device 50 according to an embodiment of the present disclosure will be described with reference to FIG.

[0012] The vehicle 1 is configured as a front-wheel drive four-wheel vehicle that transmits drive torque output from a drive power source 9 that generates drive torque for the vehicle 1 to left and right front wheels 3LF, 3RF. The vehicle 1 may be a vehicle equipped with an internal combustion engine such as a gasoline engine or a diesel engine as the drive power source 9, an electric vehicle equipped with a drive motor as the drive power source 9, or a hybrid electric vehicle equipped with both an internal combustion engine and a drive motor as the drive power source 9.

[0013] The combination of drive wheels and the drive method are not limited. For example, vehicle 1 may be a rear-wheel drive vehicle, a four-wheel drive vehicle, or an electric vehicle equipped with drive motors corresponding to the wheels 3LF, 3RF, 3LR, and 3RR (hereinafter collectively referred to as "wheels 3" unless a distinction is required). Furthermore, if vehicle 1 is an electric vehicle or a hybrid electric vehicle, vehicle 1 is equipped with a secondary battery that stores power supplied to the drive motor, and a motor or a generator such as a fuel cell that generates power to charge the battery.

[0014] Vehicle 1 is equipped with a driving force source 9, an electric steering device 15, and brake devices 17LF, 17RF, 17LR, and 17RR (hereinafter collectively referred to as "brake devices 17" unless a distinction is required) as equipment used to control the operation of vehicle 1.

[0015] The driving force source 9 outputs a driving torque that is transmitted to the front drive shaft 5F via a transmission (not shown) and a differential mechanism 7. The operation of the driving force source 9 and the transmission is controlled by a vehicle control unit 41 that includes one or more electronic control units (ECUs: Electronic Control Units).

[0016] The electric steering device 15 is provided on the front-wheel drive shaft 5F. The electric steering device 15 includes an electric motor (not shown) and a gear mechanism (not shown), and is controlled by a vehicle control unit 41 to adjust the steering angle of the front wheels 3LF, 3RF, which are drive wheels. The vehicle control unit 41 controls the driving of the electric steering device 15 so as to control the steering angle of the front wheels 3LF, 3RF, which are drive wheels, based on the steering angle of the steering wheel 13 by the driver. If the vehicle 1 is a vehicle capable of executing automatic driving control, the vehicle control unit 41 controls the electric steering device 15 based on the steering angle of the steering wheel 13 by the driver during manual driving. On the other hand, the vehicle control unit 41 controls the electric steering device 15 based on the set steering angle or steering angular velocity during driving assistance or automatic driving.

[0017] Electric steering device 15 may be a steer-by-wire type steering device in which a steering device (not shown) that receives steering input from steering wheel 13 operated by the driver and a wheel steering device (not shown) that steers the steered wheels are mechanically separated (linkless) and controlled in conjunction with each other by vehicle control unit 41. However, the present disclosure is not limited to this.

[0018] The brake devices 17LF, 17RF, 17LR, and 17RR apply braking force to the wheels 3LF, 3RF, 3LR, and 3RR, respectively. The brake devices 17 may be, for example, hydraulic brake devices. In this case, the vehicle control unit 41 controls the drive of the hydraulic unit 16 to adjust the hydraulic pressure supplied to each brake device 17. If the vehicle 1 is an electric vehicle or a hybrid electric vehicle, the brake devices 17 are used in combination with regenerative braking using a drive motor.

[0019] The vehicle control unit 41 includes one or more electronic control units (ECUs) that control the driving of the driving force source 9, the electric steering device 15, and the hydraulic unit 16. If the vehicle 1 is equipped with a transmission that changes the speed of the output from the driving force source 9 and transmits it to the wheels 3, the vehicle control unit 41 has a function to control the driving of the transmission. Note that if the vehicle 1 is a vehicle that can perform driving assistance control or automatic driving control, the vehicle control unit 41 has a function to control the driving assistance or automatic driving of the vehicle 1.

[0020] The vehicle 1 further includes an ambient environment sensor 31, a vehicle state sensor 33, a GNSS (Global Navigation Satellite System) sensor 35, a load detection device 37, a notification device 43, and the like.

[0021] The surrounding environment sensor 31 is one or more sensors that detect information about the surrounding environment of the vehicle 1. The surrounding environment sensor 31 captures an image of the surroundings of the vehicle 1 as the surrounding environment of the vehicle 1, and outputs the image data to the determination device 50. The surrounding environment sensor 31 includes, for example, a pair of left and right stereo cameras 31LF, 31RF that capture images of the area ahead of the vehicle 1. The surrounding environment sensor 31 may include, for example, any one or more sensors selected from the group consisting of a LiDAR, a radar sensor, and an ultrasonic sensor.

[0022] The vehicle state sensor 33 includes one or more sensors that detect the state of the vehicle 1. The vehicle state sensor 33 includes a steering angle sensor that detects the steering angle of the steering wheel 13. The vehicle state sensor 33 also includes an acceleration sensor that detects vibrations input to the vehicle 1. The acceleration sensor is provided in a suspension device (not shown) or the like. The vehicle state sensor 33 may include a torque sensor that detects the steering force input by the driver via the steering wheel 13. The vehicle state sensor 33 may also include a yaw rate sensor that detects the yaw rate. The vehicle state sensor 33 may also include at least one of a vehicle speed sensor, an angular velocity sensor, an accelerator position sensor, a brake stroke sensor, a brake pressure sensor, and an engine rotation speed sensor. The vehicle state sensor 33 outputs information indicative of the detection result to the determination device 50.

[0023] The GNSS sensor 35 receives satellite signals from positioning satellites such as GPS (Global Positioning System) satellites. The GNSS sensor 35 outputs position information of the vehicle 1 contained in the received satellite signals to the determination device 50. Note that the GNSS sensor 35 may be provided with an antenna, in addition to the GPS sensor, that receives satellite signals from other satellite systems that identify the position of the vehicle 1.

[0024] The load detection devices 37LF, 37RF, 37LR, and 37RR (hereinafter collectively referred to as "load detection device 37" unless a distinction is required) detect tire forces applied to the respective wheels 3LF, 3RF, 3LR, and 3RR of the vehicle 1 based on differential signals output from load cells having bridge circuits to which strain gauges are connected. The load detection devices 37LF and 37RF are provided at the connection points between the front drive shaft 5F and the front wheels 3LF and 3RF, respectively. The load detection devices 37LR and 37RR are provided at the connection points between the rear wheel axle (not shown) and the rear wheels 3LR and 3RR, respectively. The load detection device 37 may be a six-component force detector or the like that detects loads (Fx, Fy, Fz) applied in the longitudinal direction (hereinafter also referred to as the "x-axis direction"), the width direction (hereinafter also referred to as the "y-axis direction"), and the height direction (hereinafter also referred to as the "z-axis direction") of the vehicle 1, and moments (Mx, My, Mz) around the x-axis, y-axis, and z-axis, respectively. The load detection device 37 outputs information indicating the detection results to the determination device 50.

[0025] The notification device 43 is driven by the determination device 50 and notifies the driver of the vehicle 1 of various warnings by means of image display, audio output, or the like. The notification device 43 may include, for example, a display device provided in an instrument panel, or may include a speaker provided in the vehicle 1. The display device may be a display device provided in a navigation device. The notification device 43 may also include a HUD (Head Up Display) that displays on the front window of the vehicle 1.

[0026] (2. Judgment device) Referring to FIG. 2, a determination device 50 according to an embodiment of the present disclosure will be described.

[0027] (2-1. Configuration example) The determination device 50 functions as a device that determines whether or not there is a sign of an abnormality in an underbody component of the vehicle 1 by having one or more processors, such as CPUs (Central Processing Units), execute a computer program. The computer program is a computer program that causes the processor to execute the operations, described below, that should be performed by the determination device 50. The computer program executed by the processor may be recorded on a recording medium that functions as a storage unit (memory) 52, described below, or may be recorded on a recording medium built into the determination device 50 or any recording medium that can be externally attached to the determination device 50.

[0028] Recording media for recording computer programs may include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical recording media such as CD-ROMs, DVDs, and Blu-ray (registered trademark), magneto-optical media such as floptical disks, memory elements such as RAMs and ROMs, flash memories such as USB memories and SSDs, and other media capable of storing programs.

[0029] The determination device 50 is connected to an ambient environment sensor 31, a vehicle condition sensor 33, a GNSS sensor 35, a load detection device 37, a vehicle control unit 41, and a notification device 43 via a dedicated line or a communication means such as a CAN (Controller Area Network) or a LIN (Local Inter Net).

[0030] The determination device 50 includes a processing unit 51 and a storage unit 52 .

[0031] (Processing section) The processing unit 51 includes one or more processors such as a CPU and various peripheral components. Part or all of the processing unit 51 may be configured with updatable components such as firmware, or may be a program module executed by instructions from the CPU or the like.

[0032] (Storage part) The storage unit 52 is configured with one or more storage elements such as RAM or ROM connected to the processing unit 51 so as to be able to communicate with the processing unit 51. However, there is no particular limitation on the type and number of the storage units 52. The storage unit 52 stores information indicating the computer program executed by the processing unit 51, various parameters used in the calculation process, detection results, calculation results, etc.

[0033] (2-2. Functional configuration of the processing unit) The functional configuration of the processing unit 51 of the determination device 50 will be described. The processing unit 51 includes an acquisition unit 61, a pre-processing unit 62, a determination unit 63, and a notification processing unit 64. These units each have a function realized by execution of a computer program by one or more processors such as a CPU. However, some or all of the acquisition unit 61, pre-processing unit 62, determination unit 63, and notification processing unit 64 may be configured using analog circuits.

[0034] (Acquisition Department) The acquisition unit 61 acquires the tire forces of the left wheel 3LF (3LR) and the right wheel 3RF (3RR) on at least one of the front and rear sides of the vehicle 1, or the tire forces of the front wheel 3LF (3RF) and the rear wheel 3LR (3RR) on at least one of the left and right sides of the vehicle 1. Specifically, the acquisition unit 61 acquires the loads (Fx, Fy, Fz) corresponding to the above-mentioned tire forces from the load detection devices 37LF, 37RF, 37LR, 37RR provided on the respective wheels 3LF, 3RF, 3LR, 3RR of the vehicle 1.

[0035] The acquisition unit 61 also acquires vehicle body vibrations input to the vehicle 1 from an acceleration sensor included in the vehicle state sensor 33.

[0036] (Preprocessing section) The pre-processing unit 62 calculates pre-processed loads (Fx, Fy, Fz) and moments (Mx, My, Mz) by performing pre-processing on the tire forces of the wheels 3LF, 3RF, 3LR, and 3RR acquired by the acquisition unit 61. The pre-processing unit 62 extracts predetermined components from the tire forces of the wheels 3LF, 3RF, 3LR, and 3RR by band-pass filtering or the like, as will be described in detail later.

[0037] (Judgment Department) The determination unit 63 determines whether or not there is a sign of an abnormality in the suspension parts of the vehicle 1 based on the tire forces of the wheels 3LF, 3RF, 3LR, and 3RR acquired by the acquisition unit 61.

[0038] Specifically, the determination unit 63 determines whether or not there is a sign of abnormality in the suspension parts of the vehicle 1 based on the DC component of the load Fx on the front wheels 3LF (3RF) and rear wheels 3LR (3RR) among the tire forces acquired for the front wheels 3LF (3RF) and rear wheels 3LR (3RR) on at least one of the left and right sides of the vehicle 1. The determination unit 63 also determines whether or not there is a sign of abnormality in the suspension parts of the vehicle 1 based on information relating to the amplitude of the load on the front wheels 3LF (3RF) and rear wheels 3LR (3RR). Further details will be described later.

[0039] More specifically, the determination unit 63 determines whether or not there is a sign of an abnormality in the suspension components of the vehicle 1 based on the phase of the load Fy of the left wheel 3LF (3LR) and the right wheel 3RF (3RR) among the tire forces acquired for the left wheel 3LF (3LR) and the right wheel 3RF (3RR) on at least one of the front and rear sides of the vehicle 1. Further details will be described later.

[0040] It is preferable that the determination unit 63 makes the above-mentioned determination using the tire forces of the wheels 3LF, 3RF, 3LR, and 3RR that have been preprocessed by the preprocessing unit 62.

[0041] (Notification processing unit) The notification processing unit 64 controls the driving of the notification device 43 to issue various warnings to the driver of the vehicle 1 when the determination unit 63 determines that there is a sign of an abnormality in the suspension parts of the vehicle 1. The notification processing unit 64 issues the notification by outputting sound or voice, or by displaying an image or text. Details of the content of the warning will be described later, but the volume or display format may be changed depending on the severity of the warning.

[0042] (2-3. Example of operation of the determination device) An example of the operation of the determination device 50 according to an embodiment of the present disclosure will be described with reference to flowcharts shown in FIGS.

[0043] In step S10, the determination unit 63 determines whether the vehicle 1 is traveling straight. Specifically, the determination unit 63 determines whether the vehicle 1 is traveling straight based on the steering angle of the steering wheel 13 acquired by the acquisition unit 61. If it is determined that the vehicle 1 is traveling straight (step S10: YES), the process proceeds to step S11. On the other hand, if it is determined that the vehicle 1 is not traveling straight (step S10: NO), the process repeats step S10 until it is determined that the vehicle 1 is traveling straight. Here, instead of the steering angle, a steering force or a yaw rate may be used, or at least one of the steering force and the yaw rate may be used together with the steering angle. Note that in step S10, it may be determined whether the vehicle 1 is traveling straight based on the detection result from the surrounding environment sensor 31 or the GNSS sensor 35. If a negative determination is made, the process may end.

[0044] In step S11, the acquisition unit 61 acquires tire forces from the wheels 3LF, 3RF, 3LR, and 3RR of the vehicle 1. Specifically, the acquisition unit 61 acquires the loads (Fx, Fy, Fz) detected by the load detection devices 37LF, 37RF, 37LR, and 37RR from the load detection devices 37LF, 37RF, 37LR, and 37RR, respectively. The loads (Fx, Fy, Fz) acquired by the acquisition unit 61 are stored in the storage unit 52. Step S11 is performed, for example, at predetermined time intervals, and time-series data of the loads (Fx, Fy, Fz) is accumulated in the storage unit 52. Thereafter, the process proceeds to step S12. The predetermined time interval is, for example, 5 to 30 seconds, but can be set appropriately. In step S11, the acquisition unit 61 may acquire only components of the loads (Fx, Fy, Fz) necessary for the processing described below.

[0045] In step S12, the pre-processing unit 62 performs pre-processing on the tire forces acquired for each of the wheels 3LF, 3RF, 3LR, and 3RR in step S11 to calculate pre-processed tire forces. Specifically, the following pre-processing is performed.

[0046] The pre-processing unit 62 removes vibrations due to fluctuations in the drive torque output from the drive force source 9 from the tire force of each wheel 3LF, 3RF, 3LR, 3RR of the vehicle 1 by band-pass filtering or the like. The frequency of the vibrations due to fluctuations in the drive torque can be set appropriately depending on the type of motor, etc. The pre-processing unit 62 also removes vibrations in the wheel speed signals indicating the rotational angular velocities of each wheel 3LF, 3RF, 3LR, 3RR from the tire force of each wheel 3LF, 3RF, 3LR, 3RR of the vehicle 1 by band-pass filtering or the like. The frequency of the vibrations in the wheel speed signals can be set appropriately depending on the vehicle speed, for example, 0 to 10 Hz at low speeds and 1 kHz or higher at high speeds. The pre-processing unit 62 also removes (subtracts, etc.) the required drive torque from the load Fx and moment Mz of each drive wheel of the vehicle 1 (in this embodiment, the left front wheel 3LF and the right front wheel 3RF, respectively). Thereafter, the pre-processing unit 62 extracts vibration components and DC components by applying band-pass filtering or the like to the tire forces of the wheels 3LF, 3RF, 3LR, and 3RR that have been subjected to the above-described pre-processing. The process then proceeds to step S13. In this specification, the term "vibration component" refers to information about amplitude, and means, for example, a value from the maximum value to the minimum value in a certain section, such as peak-to-peak. Furthermore, the term "DC component" refers to, for example, a component of about 1 to 3 Hz or less. However, the present disclosure is not limited to these.

[0047] During manual driving, the required driving torque refers to the driving torque output from the driving force source 9 calculated based on the amount of operation of the accelerator pedal or the brake pedal. During automated driving, the required driving torque refers to the driving torque output from the driving force source 9 calculated based on the required acceleration / deceleration calculated by the vehicle control unit 41.

[0048] In step S13, the determination unit 63 determines whether the vibration component of the load Fy of each wheel 3LF, 3RF, 3LR, 3LL is equal to or less than the first threshold. If the vibration component of the load Fy of all wheels 3 is equal to or less than the first threshold (step S13: YES), the process proceeds to step S14. If there is even one wheel among all wheels 3 whose vibration component of the load Fy is not equal to or less than the first threshold (step S13: NO), this will be described later with reference to FIG. 5. The first threshold can be set appropriately taking into account vibration caused by wheel rotation.

[0049] In step S14, the determination unit 63 determines whether the vibration component of the load Fx of each of the front wheels 3LF (3RF) and rear wheels 3LR (3RR) on at least one of the left and right sides of the vehicle 1 exceeds the second threshold. If the vibration component of the load Fx of at least one of the front wheels 3LF (3RF) and rear wheels 3LR (3RR) exceeds the second threshold (step S14: YES), the process proceeds to step S15. If the vibration component of the load Fx of neither the front wheels 3LF (3RF) nor the rear wheels 3LR (3RR) exceeds the second threshold, the process ends. The second threshold can be set appropriately taking into account the vibration component caused by general road surface irregularities and the vibration component of drivetrain components including the wheels. Note that if a negative determination is made, no particular warning or the like is output.

[0050] In step S15, the determination unit 63 determines whether the DC components of the loads Fx on the front wheels 3LF (3RF) and the rear wheels 3LR (3RR) determined in step S14 are comparable to each other. If it is determined that the DC components of the loads Fx are comparable to each other (step S15: YES), this will be described later with reference to FIG. 4. On the other hand, if it is determined that the DC components of the loads Fx are not comparable to each other (step S15: NO), the process proceeds to step S16. Note that comparable means that the difference between the DC component of the load Fx on the front wheels 3LF (3RF) and the DC component of the load Fx on the rear wheels 3LR (3RR) is small enough to be considered substantially identical. A difference small enough to be considered substantially identical can be calculated appropriately by experiment, analysis, or the like.

[0051] In addition, when making the determinations in steps S14 and S15, the processing unit 51 may adjust the time axis of the load Fx of each of the front wheels 3LF (3RF) and the rear wheels 3LR (3RR). Specifically, the processing unit 51 calculates the time at which the front wheels 3LF (3RF) and the rear wheels 3LR (3RR) each pass the same point on the road surface on which the vehicle 1 is traveling, based on the vehicle speed from a vehicle speed sensor provided on the vehicle 1. Then, using the calculated time, the processing unit 51 adjusts the time axis so that the loads Fx at the times at which the front wheels 3LF (3RF) and the rear wheels 3LR (3RR) each pass the same point can be compared. At this time, information such as the wheelbase of the vehicle 1 stored in advance in the memory unit 52 may be used.

[0052] In step S16, the determination unit 63 determines to output a first warning indicating that there is a risk of a tire pressure drop or burst in either of the front wheels 3LF (3RF) and rear wheels 3LR (3RR) determined in step S15. The determination unit 63 may also determine to output a first warning indicating that there is a risk of a tire pressure drop or burst in the wheel having a larger DC component between the front wheels 3LF (3RF) and the rear wheels 3LR (3RR). Such a determination is possible because, when running resistance increases due to a drop in tire pressure or a risk of a tire burst, the DC component of the load Fx differs from its normal value. Then, the notification processing unit 64 receives the determination result of the determination unit 63 and controls the driving of the notification device 43 to issue the first warning to the driver of the vehicle 1. The process then ends.

[0053] In this way, the processing unit 51 of the determination device 50 determines whether there are any signs of abnormality in the suspension components of the vehicle 1 based on the DC components of the loads Fx of the front wheels 3LF (3RF) and rear wheels 3LR (3RR) among the tire forces obtained for the front wheels 3LF (3RF) and rear wheels 3LR (3RR) on at least one of the left and right sides of the vehicle 1.

[0054] Referring to FIG. 4, an example of the operation of the determination device 50 when a positive determination is made in step S15 will be described along with a flowchart.

[0055] In step S20, it is determined whether the vibration components of the loads Fx of the front wheels 3LF (3RF) and rear wheels 3LR (3RR) for which a positive determination was made in step S15 are comparable to each other. If it is determined that the vibration components are comparable to each other (step S20: YES), the process ends as shown in FIG. 3. On the other hand, if it is determined that the vibration components are not comparable to each other (step S20: NO), the process proceeds to step S21. Note that "comparable" means that the difference between the vibration components of the loads Fx of the front wheels 3LF (3RF) and the rear wheels 3LR (3RR) is small enough to be considered substantially identical. Furthermore, a difference small enough to be considered substantially identical can be calculated appropriately by experiment, analysis, or the like.

[0056] In step S21, the acquisition unit 61 acquires the vehicle body vibration input to the vehicle 1 from an acceleration sensor corresponding to the vehicle state sensor 33. Then, the determination unit 63 determines whether or not the vehicle body vibration contains a vibration component of the same magnitude as the vibration component of the load Fx used in the determination in step S14. If it is determined that the vehicle body vibration contains a vibration component of the same magnitude as the vibration component of the load Fx (step S21: YES), the process proceeds to step S22. On the other hand, if it is determined that the vehicle body vibration does not contain a vibration component of the same magnitude as the vibration component of the load Fx (step S21: NO), the process proceeds to step S23. Here, the pre-processing unit 62 may perform the same pre-processing as in step S12 on the vehicle body vibration before the determination unit 63 makes the determination in step S21. Note that "similar magnitude" means that the difference between the vibration component of the load Fx and the vibration component of the vehicle body vibration is small enough to be considered to be substantially identical. Furthermore, a difference small enough to be considered to be substantially identical can be determined appropriately through experimentation, analysis, or the like.

[0057] In step S22, the determination unit 63 determines to output a second warning indicating that there is a high possibility that a malfunction will occur in a suspension part, such as a suspension mount, wheel, or hub, on either the front wheel 3LF (3RF) or the rear wheel 3LR (3RR) determined in step S20. The determination unit 63 may also determine to output a second warning indicating that there is a high possibility that a malfunction will occur in a suspension part, such as a suspension mount, wheel, or hub, on either the front wheel 3LF (3RF) or the rear wheel 3LR (3RR), whichever has a larger vibration component. Then, the notification processing unit 64 receives the determination result of the determination unit 63 and controls the driving of the notification device 43 to issue the second warning to the driver of the vehicle 1. Thereafter, the process ends. Note that the second warning is a more severe warning than the third warning, which will be described later, because the vibration components of the loads Fx on the front wheel 3LF (3RF) and the rear wheel 3LR (3RR) are different from each other and vehicle body vibration is also occurring.

[0058] In step S23, the determination unit 63 determines to output a third warning recommending checking the tire air pressure, etc., for either the front wheels 3LF (3RF) or the rear wheels 3LR (3RR) determined in step S20. Then, the notification processing unit 64 receives the determination result of the determination unit 63 and controls the driving of the notification device 43 to issue the third warning to the driver of the vehicle 1. Thereafter, the process ends. Note that the third warning is a milder warning than the second warning described above, because although the vibration components of the load Fx of the front wheels 3LF (3RF) and the rear wheels 3LR (3RR) are different from each other, vehicle body vibration has not yet occurred.

[0059] In this way, the processing unit 51 of the determination device 50 determines whether or not there are signs of abnormality in the suspension parts of the vehicle 1 based on information regarding the amplitude of the load Fx of the front wheels 3LF (3RF) and rear wheels 3LR (3RR) on at least one of the left and right sides of the vehicle 1.

[0060] Referring to FIG. 5, an example of the operation of the determination device 50 when a negative determination is made in step S13 will be described along with a flowchart.

[0061] In step S30, the determination unit 63 performs the following process for the left wheel 3LF (3LR) and the right wheel 3RF (3RR) on the front or rear side of the vehicle 1, at least on the side to which the wheel 3 for which it was determined in step S13 that the vibration component of the load Fy is not equal to or less than the first threshold is attached. That is, the determination unit 63 determines whether the phases of the vibration components of the load Fy of the left wheel 3LF (3LR) and the right wheel 3RF (3RR) on at least one side of the front or rear of the vehicle 1 are different from each other. If it is determined that the phases of the vibration components of the load Fy are different from each other (step S30: YES), the process proceeds to step S31. On the other hand, if it is determined that the phases of the vibration components of the load Fy are not different from each other (step S30: NO), the process proceeds to step S34. Note that "the phases are different from each other" means that the phases of the left wheel 3LF (3LR) and the right wheel 3RF (3RR) are not the same, but does not necessarily mean that they are not the same in a mathematically strict sense. Furthermore, "phases are different from each other" may also include a case where the phases of the left wheel 3LF (3LR) and the right wheel 3RF (3RR) differ by substantially 180 degrees (that is, where the positive and negative phases are opposite).

[0062] In step S31, the acquisition unit 61 acquires the vehicle body vibration input to the vehicle 1 from an acceleration sensor corresponding to the vehicle state sensor 33. Then, the determination unit 63 determines whether or not the vehicle body vibration contains a vibration component of the same magnitude as the vibration component of the load Fy used in the determination in step S13. If it is determined that the vehicle body vibration contains a vibration component of the same magnitude as the vibration component of the load Fy (step S31: YES), the process proceeds to step S32. On the other hand, if it is determined that the vehicle body vibration does not contain a vibration component of the same magnitude as the vibration component of the load Fy (step S31: NO), the process proceeds to step S33. Here, the pre-processing unit 62 may perform the same processing as the pre-processing in step S12 on the vehicle body vibration before the determination unit 63 makes the determination in step S31.

[0063] In step S32, the determination unit 63 determines to output a fourth warning indicating that there is a risk that either the left wheel 3LF (3LR) or the right wheel 3RF (3RR) determined in step S30 may fall off. Then, the notification processing unit 64 receives the determination result of the determination unit 63 and controls the driving of the notification device 43 to issue the fourth warning to the driver of the vehicle 1. The process then ends. Such a determination is possible because, when there is a risk that the wheel 3 may fall off, the phases of the vibration components of the load Fy of the left wheel 3LF (3LR) and the right wheel 3RF (3RR) are different from each other due to loosening of the wheel nuts of the wheel 3, etc. The fourth warning is a more severe warning than the fifth warning, which will be described later, because the phases of the vibration components of the load Fy of the left wheel 3LF (3LR) and the right wheel 3RF (3RR) are different from each other and even vehicle body vibration is occurring.

[0064] In step S33, the determination unit 63 determines to output a fifth warning recommending checking the air pressure, etc., for either the left wheel 3LF (3LR) or the right wheel 3RF (3RR) determined in step S30. Then, the notification processing unit 64 receives the determination result of the determination unit 63 and controls the driving of the notification device 43 to issue the fifth warning to the driver of the vehicle 1. Thereafter, the process ends. The fifth warning is a milder warning than the fourth warning because although the phases of the vibration components of the load Fy of the left wheel 3LF (3LR) and the right wheel 3RF (3RR) are different from each other, vehicle body vibration has not yet occurred.

[0065] On the other hand, if a negative determination is made in step S30, then in step S34 the determination unit 63 determines that the vehicle 1 is traveling on a rough road. Such a determination is possible because, when the vehicle 1 is traveling on a rough road, the left wheel 3LF (3LR) and the right wheel 3RF (3RR) are simply subjected to a load Fy of the same magnitude, and the phases of the vibration components of the load Fy are also substantially the same. Therefore, by focusing on the phase of the vibration component of the load Fy, it is possible to distinguish whether the vehicle 1 is traveling on a rough road or whether there is a risk of the wheel 3 coming off. Note that a rough road refers to a road or the like on which vehicle body vibration exceeds a predetermined value due to bumps or ruts on the road.

[0066] In this way, the processing unit 51 of the determination device 50 determines whether or not there are signs of abnormality in the suspension parts of the vehicle 1 based on the phase of the vibration component of the load Fy of the left wheel 3LF (3LR) and the right wheel 3RF (3RR) on at least one of the front and rear sides of the vehicle 1.

[0067] From the viewpoint of avoiding the influence of noise from the load detection device 37 such as a six-component force detector, it is preferable that the notification processing unit 64 outputs the first to fifth warnings described above when the events relating to the first to fifth warnings described above occur a predetermined number of times or more. The predetermined number of times is, for example, about several tens of times per minute, but the present disclosure is not limited to this and can be set as appropriate.

[0068] (effect) As described above, the processing unit 51 of the determination device 50 according to one embodiment acquires the tire forces of the left wheel 3LF (3LR) and the right wheel 3RF (3RR) on at least one of the front and rear sides of the vehicle 1, or the tire forces of the front wheel 3LF (3RF) and the rear wheel 3LR (3RR) on at least one of the left and right sides of the vehicle 1. Then, the processing unit 51 determines whether or not there is a sign of an abnormality in the suspension components of the vehicle 1 based on the acquired tire forces.

[0069] According to this configuration, it is possible to determine whether or not there is a sign of abnormality in the suspension components of the vehicle 1 based on the tire force of the wheel 3 of the vehicle 1. In this way, by using the tire force, it is possible to accurately predict the sign of abnormality even if there is insufficient information for estimating the tire state, such as the angular velocity of the wheel and the tire pressure. For example, it is possible to accurately predict the sign of abnormality even if the wheel 3 is increased or decreased in size. Furthermore, by using the tire force, it is possible to accurately predict the sign of abnormality regardless of the type of wheel. Therefore, it is possible to issue a warning even for wheels that are not equipped with air pressure sensors (TPMS: Tire Pressure Monitoring System).

[0070] Although preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art to which the present disclosure pertains can conceive of various modifications or alterations within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure. For example, the functions included in each component or step can be rearranged so as not to be logically inconsistent, and multiple components or steps can be combined or divided into one.

[0071] As one modified example, the processing unit 51 of the determination device 50 may determine whether to correct the acquired tire forces based on the load Fz applied in the height direction of the vehicle 1 among the tire forces acquired for the front wheel 3LF (3RF) on at least one of the left and right sides of the vehicle 1, and the load Fz applied in the height direction of the vehicle 1 among the tire forces acquired for the rear wheel 3LR (3RR) on that side. Specifically, the processing unit 51 acquires the loads (Fxlf, Fylf, Fzlf) on the left front wheel 3LF and the loads (Fxlr, Fylr, Fzlr) on the rear wheel 3LR. If either of the loads Fzlf and Fzlr exceeds a third threshold, the processing unit 51 corrects the load Fxlf on the left front wheel 3LF and the load Fxlr on the left rear wheel 3LR. The third threshold can be set appropriately taking into account the effect on tire forces of differences in weight distribution between the front and rear of the vehicle 1. For example, for the left front wheel 3LF, the processing unit 51 can perform correction using the following equation (1) by using the ratio of the load Fzlf of the front wheel 3LF to the sum of the front and rear loads Fzlf, Fzlr on the left side. Also, for example, for the left rear wheel 3LR, the processing unit 51 can perform correction using the following equation (2) by using the ratio of the load Fzlr of the rear wheel 3LR to the sum of the front and rear loads Fzlf, Fzlr on the left side. This makes it possible to take into account the influence on tire force due to differences in the front and rear weight distribution of the vehicle 1. Note that the y component of the load can also be corrected in a similar manner. Also, a similar correction can be made for the right side of the vehicle 1.

[0072]

number

[0073]

number

[0074] The technology disclosed herein can also be realized as a vehicle 1 equipped with the determination device 50 described in the above-mentioned embodiment, a determination method executed by the determination device 50, a computer program that causes a computer to function as the above-mentioned determination device 50, and a non-transitory tangible recording medium on which the computer program is recorded. [Explanation of symbols]

[0075] 1: vehicle, 50: determination device, 51: processing unit, 52: storage unit, 61: acquisition unit, 62: pre-processing unit, 63: determination unit, 64: notification processing unit

Claims

1. A determination device for determining whether or not there is a sign of abnormality in a vehicle suspension component, one or more processors; and one or more memories communicatively coupled to the one or more processors; the one or more processors: acquiring tire forces of left and right wheels on at least one of a front side and a rear side of the vehicle, or tire forces of front and rear wheels on at least one of a left side and a right side of the vehicle; determining whether or not there is a sign of an abnormality in the suspension component of the vehicle based on the acquired tire force; Judgment device.

2. the one or more processors: determining whether or not there is a sign of an abnormality based on a DC component of a load applied to the front wheels and the rear wheels in a longitudinal direction of the vehicle, among the tire forces acquired for the front wheels and the rear wheels on at least one of the left side and the right side of the vehicle; The determination device according to claim 1 .

3. the one or more processors: determining whether or not there is a sign of an abnormality based on information about the amplitude of the load on the front wheels and the rear wheels; The determination device according to claim 2 .

4. the one or more processors: determining whether or not there is a sign of an abnormality based on a phase of a load applied to the left wheel and the right wheel in a vehicle width direction of the vehicle, among the tire forces acquired for the left wheel and the right wheel on at least one of the front side and the rear side of the vehicle; The determination device according to claim 1 .

5. the one or more processors: determining whether to correct the acquired tire forces based on a load applied in the height direction of the vehicle out of the tire forces acquired for the front wheels on at least one of the left side and the right side of the vehicle, and a load applied in the height direction of the vehicle out of the tire forces acquired for the rear wheels; The determination device according to claim 1 .

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