Data recording device and data recording program

Abstract

Data recording device (10) installed in a vehicle and allowing a recording section (12) to record data generated in the vehicle, comprising: Data acquisition device (S110) which acquires a variety of diagnostic data contained in the data generated in the vehicle; Importance level setting means (S130) which sets an importance level indicating the importance of an abnormal part according to each part of the diagnostic data, based at least on the type of diagnostic data; Anomaly grade setting tools (S140) which set for each part of the diagnostic data a grade of anomaly indicating an extent of the anomaly, using models created for each part of the diagnostic data and each type of diagnostic data; Recording parameter setting means (S150), which sets for each part of the diagnostic data a recording parameter that affects the data size when a recording section is allowed to record data, based on the importance level and the degree of anomaly, and Recording means (S155, S160) which allow a recording section to record at least part of the generated data according to the recording parameter, where the recording device (S155, S160) is configured: to set a priority level for each part of the diagnostic data to be recorded, so that the priority level of each part of the diagnostic data increases with an increase in the importance level of the corresponding part of the diagnostic data and If at least two parts of the diagnostic data have the same level of importance, the priority level of the at least two parts of the diagnostic data is to be determined based on the degree of anomaly of the corresponding parts of the diagnostic data.

Description

CROSS-REFERENCE TO A RELATED APPLICATION

[0001] This application is based on and claims the benefit of priority from earlier Japanese patent application JP 2014-95 984 A, filed on May 7, 2014, which is incorporated by reference in its entirety. Background (Technical Area)

[0002] The present invention relates to a data recording apparatus that records data generated in an own vehicle and a data recording program. (State of the art)

[0003] A data recording device is known which, according to an error pattern (importance of the error parts), changes the sampling rate when recording data in order to save memory capacity when recording the data (for example, reference to JP 2007-41952 A).

[0004] However, since this data recorder sets a similar sampling rate regardless of the error magnitude, data is collected unnecessarily when the error magnitude is small, and storage space is consumed unnecessarily.

[0005] Further relevant prior art is known from DE 197 07 847 A1, JP H09- 126 045 A and JP 2003- 312 553 A. BRIEF DESCRIPTION OF THE INVENTION

[0006] The object of the present invention is to provide a data recording device that records data generated in a vehicle and can optimize the memory capacity during data recording. Furthermore, the object of the present invention is to provide a corresponding data recording program.

[0007] The problem is solved by the features of claims 1 or 9.

[0008] As one aspect of this embodiment, a data recording device is installed in a vehicle and allows a recording section to record data generated in the vehicle. The device includes: data acquisition means that acquires a plurality of diagnostic data included in the data generated in the vehicle; importance level setting means that sets an importance level indicating the importance of an abnormal part according to each piece of diagnostic data based on at least the type of diagnostic data; abnormality level setting means that sets an abnormality level indicating a degree of abnormality for each piece of diagnostic data by utilizing models established for each piece of diagnostic data and each type of diagnostic data;Recording parameter setting means that sets, for each piece of the diagnostic data, a recording parameter that affects the data size when the recording section is allowed to record data based on the degree of importance and the degree of abnormality, and recording means that allows the recording section to record at least part of the generated data according to the recording parameters; BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In the accompanying drawings: Fig. 1 is a block diagram showing a schematic configuration of a data recording system; Fig. 2 is a flowchart showing a data recording process performed by the CPU of a data recording device; Fig. 3A, Fig. 3B and Fig. 3C are figures illustrating a method for calculating an importance level; Fig. 4 is a diagram for explaining an example of an importance-degree map according to a modification; Fig. 5A and Fig. 5B are illustrations for explaining a method for calculating an anomaly degree; Fig. 6A and Fig. 6B are diagrams for explaining a method of setting parameters; Fig. 7 is a diagram for explaining an example of the timing of sensor data collection; Fig. 8A and Fig. 8B are illustrations for explaining an example of a method of setting a priority level when storing data; Fig. 9 is a flowchart showing a data storage process in the data recording process; Fig. 10A and Fig. 10B are graphs illustrating an example of a method of setting a priority level according to a modification; and Fig. 11A and Fig. 11B are illustrations for explaining a method of setting parameters according to a modification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Embodiments of the present invention will be described below with reference to the accompanying drawings. It should be noted that in the following embodiments, like reference numerals designate substantially like parts. (Structure of the embodiment)

[0011] A data recording system 1 is installed in a car (own vehicle), such as a passenger vehicle. The data recording system 1 changes the data size when recording data, taking into account an importance level indicating the importance of an abnormal part of the own vehicle and an abnormality level indicating the extent of the abnormality, to optimize the recording data size.

[0012] Especially, as in Fig. As shown in Figure 1, the data recording system 1 includes a data recording device 10, various ECUs (electronic control units) 21 to 24, and various sensors 25. The data recording device 10, the electronic control units 21 to 24, and the sensors 25 are connected to a communication line 5 for communication with each other.

[0013] The ECUs 21 to 24 include an engine control unit (engine ECU) 21 that controls the engine of the host vehicle, a brake control unit 22 that controls the brakes of the host vehicle, a steering control unit 23 that controls a steering angle of the host vehicle, and a suspension control unit 24 that controls the vehicle height and attitude of the host vehicle. The sensors 25 include a vehicle speed sensor that measures the speed of the host vehicle, an acceleration sensor that measures the acceleration of the host vehicle, and a yaw rate sensor that measures the angular velocity of the host vehicle.

[0014] The control units 21 to 24 output calculation results thereof and values ​​received from the sensors connected thereto to the communication line 5. The sensors 25 output sensing signals to the communication line 5.

[0015] The data recording device 10 is configured as a computer including a CPU 11 and a memory 12, such as ROM or RAM. The CPU 11 performs various operations, described later, based on a program (data recording program) stored in the memory 12. While performing such processes, the data recording device 10 allows the memory 12 to record and temporarily store a portion of the data received via the communication link. Note that the data recording device 10 temporarily stores all received data in the memory 12 (at least during the maximum value of |TS|, which is the absolute value of the storage start time TS, described later). (Process of the embodiment)

[0016] In the data recording unit 1 configured as described above, the CPU 11 in the data recording device 10 performs a data recording process which is Fig. 2. The data recording process allows data to be recorded to memory 12, taking into account the degree of importance and the degree of abnormality of the received data. Additionally, the data recording process starts when power is supplied to the vehicle. Thereafter, the data recording process is repeatedly performed at a constant period.

[0017] In the data recording process, as in Fig. 2, first in step S110, the CPU 11 receives data temporarily recorded in the memory 12. The data represents the output values ​​of the control units 21 to 24 and the sensors 25.

[0018] Further, in step S120, the CPU 11 sets a variable k to 1. The variable k is a value for indicating the type of abnormality (the type of abnormal condition) that is detected and increases to the prepared number K, which is the number of types of abnormal conditions, in the later process.

[0019] Next, in step S130, the CPU 11 performs an importance degree calculation process. Note that steps S130 to S165 are performed for each piece of data previously set as diagnostic data for abnormality detection, which diagnostic data is included in the temporarily recorded data in the memory 12.

[0020] The severity level indicates the importance of an anomalous part. The anomalous part is classified by an ID that identifies the type of data. The ID is included in the diagnostic data.

[0021] In the importance calculation process, as in Fig. 3A, the CPU 11 first obtains its own vehicle speed v from the vehicle speed sensor of the sensors 25 in step S210.

[0022] Next, in step S220, the CPU 11 calculates the importance degree y k . As in Fig. 3B shows how the importance level y k , the functions G k set according to the type of anomaly conditions. For example, as in Fig. As shown in Figure 3C, each of the functions G k a function of the vehicle's own speed v.

[0023] Especially for diagnostic data of basic functional systems, including the powertrain system, steering system, braking system, and the like, which can affect the safety of a moving vehicle, the importance level is set to a relatively high value regardless of the vehicle speed. As the vehicle speed increases, the importance level increases.

[0024] In addition, for the diagnostic data of a body system, including a door lock system, a power window system, an air conditioning system, and the like, which does not affect vehicle driving safety but is relatively important, the importance level is set lower than that of the diagnostic data of the basic function system and higher than that of the diagnostic data of an entertainment system, which will be described later. Furthermore, for the diagnostic data of the entertainment system, including an audio system, an internal vehicle lighting system, and the like, which does not affect vehicle driving safety but only affects passenger comfort, the importance level is set lower than that of the diagnostic data of the body system.

[0025] It should be noted that, as in Fig. 3C, for example, for the entertainment system diagnostic data, the importance level can be set as if it were constant, regardless of the vehicle speed v. In addition, as shown in Fig. As shown in Figure 4, the importance level can be a fixed value, according to the type of anomaly condition.

[0026] Upon completion of the above steps, the importance calculation process ends and the data recording process returns to Fig. 2. Then, in step S140, the CPU 11 performs an anomaly-degree calculation process to calculate the anomaly. The anomaly degree indicates the extent of the anomaly in the diagnostic data.

[0027] In the anomaly degree calculation process, as in Fig. As shown in Figure 5A, the CPU 11 calculates an abnormality level using a model based on the distribution of the diagnostic data previously collected under normal conditions and the received diagnostic data. In this case, for example, a classifying support vector machine (SVM) can be used.

[0028] Specifically, the following expression is determined using Mahalanobis' generalized distance between the mean of the distribution of the normal diagnostic data and the observed diagnostic data, or a normal mean function f(t) and an observed mean function g(t). The normal mean function f(t) is an average function of the normal diagnostic data. The observed mean function g(t) is an average function of a plurality of pieces of the diagnostic data. ‖f−g‖k:=∫|f(t)−g(t)|kdtk

[0029] Here, the distance d between the distribution of the normal diagnostic data and that of the observed diagnostic data is calculated.

[0030] After the distance d is calculated, an anomaly degree s of the function is obtained by inputting the distance d to a predetermined function. For example, as in Fig. As shown in Figure 5B, the function can be a linear form or a quadratic form at a distance d. If the distance d is no more than a normal threshold, the anomaly degree s = 0. Time sequence information can be incorporated into the analysis. For example, the weight of new data can be increased.

[0031] Next, in S150, the CPU 11 determines data storage information. In this process, the CPU 11 sets parameters that can affect the data size, such as the type of data (sensor data type), storage start time (TS k,m ), memory stop time (TE k,m ), and a sampling period (SPk,m ), using the importance level y k and the anomaly degree s.

[0032] For example, as shown in function 6A, the type of sensor data (SD m ), which depends on the type of anomaly condition (FD k ) is to be saved. Based on the type of anomaly conditions and the type of sensor data, the CPU 11 selects a function (F k,m ) to set the memory start time, the memory stop time, and the sampling period. An example of function F k,m is shown in the following expression: Fk,m(s):=[TSk.m(s),TEk,m(s),SPk,m(s)]

[0033] As in Fig. As shown in Figure 6B, the storage start time and the storage stop time are set so that the data collection time period becomes longer as the anomaly degree s becomes higher. It should be noted that time 0 in the graph indicates a time at which the trigger for saving data (the anomaly degree s ≠ 0) is generated.

[0034] In addition, the memory start time and memory stop time also depend on the importance level y k If the importance level y k of the diagnostic data becomes higher, the data collection period is extended. For example, the storage start time and storage stop time, which are set depending on the abnormality level s, can be set depending on the severity level y. k be modified.

[0035] Additionally, Fig. 6B that data is not collected when the anomaly level is 0. The graph shown in Fig. 6B is an example of the function F k,m. Every function F k,m may vary.

[0036] In addition, the sampling period can be set, for example, as inversely proportional to the anomaly degree s. That is, if the anomaly degree s and the importance degree y k higher, the sampling period can be set smaller.

[0037] Under the setting described above, as in Fig. As shown in Figure 7, the data collection time and sampling period are individually set depending on the type of sensor data being stored.

[0038] Next, in step S155, the CPU 11 determines whether or not the recording timing is present. If the recording timing is not present (S155: NO), the process proceeds to step S165 described later. If the recording timing is present (S155: YES), the CPU 11 performs a data saving operation (S160).

[0039] In the data storage process, as in Fig. 8A, the CPU 11 sets a priority level depending on the importance level y k and the abnormality level s of the diagnostic data, and overwrites data that has a lower priority level if the capacity of the memory 12 is insufficient. For example, as in Fig. As shown in Figure 8B, the CPU 11 stores data having a higher priority level at the lower numbered address in the memory 12. When the memory 12 is full, the CPU 11 deletes the data having a lower priority level.

[0040] The data storage process is explained in detail. As in Fig. As shown in Figure 9, in step S310, the CPU 11 obtains data storage information. In this step, the CPU 11 obtains information about the degree of importance, the degree of abnormality, the storage start time, and the storage stop time.

[0041] Next, in step S320, the CPU 11 adds the data storage information to the database. In step S330, the CPU 11 calculates the total data size (DBS) including the data in the memory 12. Next, in step S340, the CPU 11 compares the capacity of the memory 12 (DB max ) with the total data size.

[0042] If the capacity of the memory 12 is equal to or greater than the total data size (S340: NO), the data storage operation is terminated. If the capacity of the memory 12 is less than the total data size (S340: YES), in steps S350 to S370, the CPU 11 sorts the stored data according to the importance level, the abnormality level, and the storage start time. That is, the CPU 11 sorts the stored data according to the priority level as described above. For a plurality of data pieces with the same priority level, a higher priority level is applied to the more recent data.

[0043] Next, in step S380, the CPU 11 writes the data in the order of priority into the memory 12 and completes the data storage operation. Upon completion of the data storage operation, then returning to Fig. 2, in step S165, the CPU determines whether the obtained data has been stored or not (that is, whether or not the storage stop time has passed).

[0044] If the data has not been saved (S165: NO), the process returns to step S155. If the data has been saved (S165: YES), in step S170, the CPU 11 compares the variable k with the number K, which is the number of types of abnormal conditions. If the variable k is less than the number K (S170: NO), the CPU 11 increments the variable k, and the process returns to step S130.

[0045] If the variable k is equal to (or greater than) the number K (S170: YES), the CPU 11 ends the data recording process. (Advantages of the embodiment)

[0046] The data recorder 10 (CPU 11) receives multiple types of diagnostic data included in the data generated in the vehicle (S110) and sets a severity level indicating the severity of an abnormal part for each piece of diagnostic data based on at least the type of diagnostic data (S130). Additionally, the data recorder 10 sets an abnormality level for each piece of diagnostic data, indicating the extent of the abnormality, using the received diagnostic data and models created for each type of normal diagnostic data (S140).

[0047] The data recording device 10 sets a recording parameter for each piece of diagnostic data that affects the data size when allowing a recording section to record data based on the degree of importance and the degree of abnormality (S150). Additionally, the data recording device 10 allows the recording section to record at least a portion of the generated data according to the recording parameters (S155, S160).

[0048] Since the data recording device 10 sets the recording parameters that affect the data size in consideration of an importance degree indicating the importance of an abnormal part and an anomaly degree indicating a degree of the abnormality, the recording data size can be optimized.

[0049] In addition, the data recording device 10 sets the abnormality degree using a model based on a distribution of the diagnostic data previously collected under normal conditions.

[0050] Since the data recording device 10 uses the distribution when calculating the abnormality degree, the abnormality degree can be appropriately calculated according to the distribution of the diagnostic data collected under normal conditions. Furthermore, the calculation of the abnormality degree can be simplified.

[0051] In addition, the data recording device 10 sets the anomaly degree using a divergence degree calculated from the model and the received diagnostic data.

[0052] Since the data recording device 10 sets the anomaly degree using the divergence degree, the process for setting the anomaly degree can be simplified.

[0053] In addition, when the divergence degree is less than a predetermined lower limit, the data recorder 10 sets the anomaly degree to zero.

[0054] Since the data recorder 10 ignores the degree of divergence smaller than the lower limit, the calculation can be simplified. Furthermore, the data size can be reduced.

[0055] In addition, the data recording device 10 sets at least one of the types of data, the data size, a sampling rate, and a sampling time range as recording parameters.

[0056] The data recording device 10 can reliably change the data size to be recorded according to the degree of importance and the degree of anomaly.

[0057] Additionally, the data recording device 10 determines the presence or absence of a recording area in the recording section. If no recording area exists, the data recording device 10 selects the data whose importance level is lower than a predetermined threshold from the recorded data in the recording section as a target to be overwritten. The data recording device 10 then overwrites the data selected as the target to be overwritten with the data to be recorded according to the recording parameters.

[0058] According to the data recording device 10, important data can be prevented from being overwritten when there is no recording area.

[0059] In addition, the data recording device 10 sets the abnormality level obtained when the abnormality affects the vehicle operation safety higher in priority than the abnormality level obtained when the abnormality does not affect the vehicle operation safety.

[0060] According to the data recording device 10, larger data can be recorded when the vehicle is in a situation where the vehicle is difficult to operate.

[0061] In addition, the data recording device 10 sets the degree of importance higher as the speed of the own vehicle increases.

[0062] That is, since the risk of the own vehicle increases as the own vehicle speed increases, the importance level is set higher. According to the data recorder 10, the importance level can be set appropriately. (Other embodiments)

[0063] It should be understood that the present application is not limited to the arrangement as described above, but any and all modifications, variations or equivalents which may occur to a person skilled in the art should be considered to fall within the scope of the present invention.

[0064] In the above example, the degree of importance is defined as a function of the vehicle speed v. However, as in Fig. 10A, the importance level can be a constant depending on the anomaly condition (FD k ). In addition, in the above embodiment, the priority level becomes higher as the importance level becomes higher. However, as in Fig. As shown in Figure 10B, the priority level can be set based on an appropriate balance between the degree of importance and the degree of abnormality. It should be noted that diagnostic data related to the basic functional systems are recorded preferentially.

[0065] Additionally, in the above embodiment, the memory start time (TS k,m ) and the memory stop time (TE k,m ) are set variably depending on the degree of anomaly. However, as in Fig. As shown in Figure 11A, these timings can be set to be constant. Additionally, the sampling rate f can be adjusted using a function in which the sampling rate increases (i.e., the sampling period becomes smaller) as the anomaly degree s increases.

[0066] In the above embodiment, older data is preferably overwritten. However, an overwritten area can be determined depending on the types of anomaly conditions. In particular, a function H k,m provided that have an importance level y k based on the input anomaly level S and the data acquisition time t. yk=Hk,m(s,t),TSk,m(s)≤∀t≤TEk,m(s)

[0067] In the above expression, y k indicates the importance level, s indicates the anomaly level, and t indicates the data collection time.

[0068] Therefore, a priority level is determined in the database (memory 12) along the time axis, and diagnostic data with a low priority level can be preferentially overwritten. Accordingly, important data with a higher priority level can be reliably stored in a finite capacity. In addition, diagnostic data with a relatively low priority level can also be effectively stored. (Relationship between the embodiment and the means of the invention)

[0069] The data recording device 10 in the above embodiment corresponds to a data recording device. In the above embodiment, step S110 performed by the data recording device 10 corresponds to the data acquisition means (section).

[0070] Step S130 corresponds to importance level setting means (section). Step S140 corresponds to abnormality level setting means (section). Step S150 corresponds to recording parameter setting means (section). Steps S155 and S160 correspond to recording means (section).

[0071] Step S340 corresponds to recording area determining means (section).

[0072] Steps S350 to S380 correspond to selection means for a target (section) to be overwritten.

[0073] Aspects of the embodiment described above are summarized below.

[0074] As one aspect of the embodiment, a data recording device 10 is provided. Data acquisition means (S110) acquires a plurality of types of diagnostic data included in the data generated in the vehicle. Importance level setting means (S130) sets an importance level indicating the importance of an abnormal part corresponding to each piece of diagnostic data based on at least the type of diagnostic data. Abnormality level setting means (S140) sets an abnormality level indicating a degree of abnormality for each piece of diagnostic data using models created for each piece of diagnostic data and each type of diagnostic data.

[0075] Additionally, recording parameter setting means (S150) sets a recording parameter for each piece of diagnostic data that affects the data size when the recording section is allowed to record data based on the degree of importance and the degree of abnormality. Recording means (S155, S160) allow the recording section to record at least a portion of the generated data according to the recording parameters.

[0076] Since, according to the data recording device, the recording parameters that affect the data size are set by considering an importance degree indicating the importance of an abnormal part and an anomaly degree indicating the extent of the anomaly, the storage capacity when recording the data can be optimized.

[0077] It is noted that a data recording program may be provided which allows a computer to operate as each of the means of the data recording device.

Claims

[1] A data recording device (10) installed in a vehicle and allowing a recording section (12) to record data generated in the vehicle, comprising: Data acquisition means (S110) which acquire a plurality of diagnostic data contained in the data generated in the vehicle; Importance level setting means (S130) which sets an importance level indicating the importance of an abnormal part corresponding to each piece of the diagnosis data based at least on the type of the diagnosis data; Anomaly degree setting means (S140) that sets, for each piece of the diagnosis data, a degree of anomaly indicating a degree of the anomaly using models created for each piece of the diagnosis data and each type of diagnosis data; Recording parameter setting means (S150) which sets, for each piece of the diagnosis data, a recording parameter that affects the data size when a recording section is allowed to record data based on the degree of importance and the degree of abnormality, and Recording means (S155, S160) which allow a recording section to record at least part of the generated data according to the recording parameter, wherein the recording means (S155, S160) is configured: to set a priority level of each piece of diagnostic data for recording, so that the priority level of each piece of diagnostic data becomes higher with an increase in the importance level of the corresponding piece of diagnostic data, and if at least two pieces of the diagnostic data have the same degree of importance, to determine the priority degree of the at least two pieces of the diagnostic data based on the abnormality degree of the corresponding one of the at least two pieces of the diagnostic data. [2] A data recording apparatus according to claim 1, wherein said abnormality degree setting means sets the degree of abnormality using a model based on the distribution of the diagnostic data collected under normal conditions. [3] A data recording apparatus according to claim 1, wherein said abnormality degree setting means sets the degree of abnormality using a degree of divergence calculated from said model and said diagnosis data. [4] A data recording apparatus according to claim 3, wherein the anomaly degree setting means sets the degree of anomaly to 0 when the degree of divergence is smaller than a predetermined lower limit. [5] A data recording apparatus according to claim 1, wherein the recording parameter setting means sets at least one of a type of data, the data size, a sampling rate, and a capture time range. [6] A data recording device according to claim 1, further comprising: Recording area determining means (S340) which determines the presence or absence of an area for recording in the recording section; and Overwrite target selecting means (S350 to S380) which selects data as the overwrite target whose degree of importance is lower than a predetermined threshold from the recorded data in the recording section if there is no area for recording, wherein the recording media overwrite the data selected as the target to be overwritten with the data to be recorded in accordance with the recording parameters. [7] A data recording apparatus according to claim 1, wherein said importance level setting means sets the importance level in an abnormal condition in which the vehicle is difficult to operate higher than the importance level in an abnormal condition in which the vehicle operation safety is not impaired. [8] A data recording apparatus according to claim 1, wherein said importance level setting means sets the importance level higher as the vehicle speed increases. [9] A data recording program which allows a computer to operate as any of the means of the data recording apparatus according to claim 1.

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