Driving assistance device, driving assistance processing method, and recording medium

Abstract

This driving assistance device comprises a sound source data storage unit in which a plurality of sound source data are stored, the plurality of sound source data being configured from a plurality of measures or parts, and the plurality of sound source data being classified according to the ease of noticing changes in a playback method for the sound source data. The driving assistance device selects sound source data to be played back from among the plurality of sound source data in accordance with acquisition of information pertaining to the sensitivity of the driver with respect to changes in the playback method. When the behavior of the vehicle is stable, the sound source data is advanced to the next measure or the next part in a predetermined order, and the sound source data is played back normally at a constant playback volume and at a constant playback speed. When the behavior of the vehicle is not stable, the sound source data is played back using a playback method different from the normal playback.

Description

Driving assistance device, driving assistance processing method, and recording medium

[0001] The present disclosure relates to a driving assistance device, a driving assistance processing method, and a recording medium for improving vehicle driving skills.

[0002] Vehicle driving skills vary from driver to driver. Driving skills affect ride comfort and traffic safety. In response to this, various devices have been proposed that assess driver performance, notify the driver of the assessment results, and provide advice.

[0003] For example, Patent Document 1 proposes a driving assistance device that accurately determines a driving operation state and allows a driver to know information about an overall evaluation of the driving operation state in the current driving session, thereby improving driving skills in the next driving session. Specifically, Patent Document 1 discloses a driving assistance device that includes: a change amount calculation unit that calculates a first related value related to an amount of change in acceleration; a jerk calculation unit that calculates a second related value related to a jerk; a state determination unit that determines whether the driving state is smooth or shaky from the first and second related values ​​according to a predetermined determination criterion using a vibration model; and a comprehensive determination unit that calculates a score for the determination result by the state determination unit in the current driving session, divides the score by the number of determinations made by the state determination unit in the current driving session to calculate a first evaluation index, and calculates an overall evaluation score for the driving operation state in the current driving session based on the first evaluation index.

[0004] JP 2012-198344 A

[0005] However, because the driving assistance device described in Patent Document 1 evaluates a series of driving operations performed during the current drive, it is difficult for the driver to understand at what point in time the driving operations were evaluated. In contrast, if the evaluation results and advice on driving operations are presented to the driver while driving using audio text or image display, the driver's attention to the surroundings of the vehicle may decrease when checking the evaluation results or the advice. Furthermore, while it is possible to alert the driver when the vehicle's behavior becomes unstable while the driver is driving, this may give the impression that the driver's driving is being denied, and may be less effective in improving the driving skills of drivers who have little motivation to improve their driving skills.

[0006] In response to this, it is conceivable to inform the driver of the vehicle's behavioral stability by changing the auditory stimulus (sound, etc.) according to the vehicle's behavioral stability. However, the sensitivity to changes in auditory stimuli varies from person to person depending on the driver's attention to the surroundings while driving the vehicle and the sound source used. Therefore, there is a risk that the driver will not notice the change in auditory stimulus, resulting in a reduced effect of stabilizing the vehicle's behavior.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present disclosure is to provide a driving assistance device, a driving assistance processing method, and a recording medium that are capable of improving the driver's driving skills by presenting changes in the vehicle's behavioral stability to the driver by changing auditory stimuli according to the vehicle's behavioral stability.

[0008] In order to solve the above problem, according to an aspect of the present disclosure, there is provided a driving assistance device that presents a vehicle's behavior stability to a driver through auditory stimulation, the driving assistance device comprising: one or more processors; one or more memories communicatively connected to the one or more processors; and a sound source data storage unit communicatively connected to the one or more processors and storing a plurality of sound source data composed of a plurality of measures or parts, the plurality of sound source data being classified according to how easily the driver notices a change in a playback method of the sound source data, wherein the one or more processors execute the following operations: an acquisition process that acquires information on the driver's sensitivity to changes in the playback method; a sound source selection process that selects sound source data to be played back from the plurality of sound source data according to the driver's sensitivity; a behavior stability determination process that determines the stability of the vehicle's behavior; and a sound source playback process that, if the vehicle's behavior is stable, progresses to the next measure or next part in a predetermined order and plays back the sound source data normally at a constant playback volume and a constant playback speed, and, if the vehicle's behavior is unstable, plays back the sound source data by a playback method different from the normal playback.

[0009] In order to solve the above problem, according to another aspect of the present disclosure, there is provided a driving assistance processing method for presenting the stability of vehicle behavior to a driver through auditory stimulation, in which a computer acquires information on the driver's sensitivity to changes in the playback method, selects sound source data to be played from the plurality of sound source data according to the sensitivity of the driver, determines the stability of the vehicle's behavior, and, if the vehicle's behavior is stable, progresses to the next measure or next part in a predetermined order and plays the sound source data normally at a constant playback volume and a constant playback speed, and if the vehicle's behavior is unstable, plays the sound source data using a playback method different from the normal playback.

[0010] In order to solve the above problem, according to one aspect of the present disclosure, there is provided a non-transitory tangible recording medium having recorded thereon a computer program that causes a computer to perform the following operations: acquire information on the driver's sensitivity to changes in the playback method; select sound source data to be played from the plurality of sound source data according to the driver's sensitivity; determine the stability of the vehicle's behavior; and, if the vehicle's behavior is stable, proceed to the next measure or next part in a predetermined order and play the sound source data normally at a constant playback volume and a constant playback speed; and, if the vehicle's behavior is unstable, play the sound source data using a playback method different from the normal playback.

[0011] As described above, according to the present disclosure, the behavioral stability of the vehicle driven by the driver can be improved by changing the auditory stimulus depending on the behavioral stability of the vehicle.

[0012] 1 is a schematic diagram showing a vehicle to which a driving assistance device according to the present disclosure is applied; FIG. 2 is a block diagram showing an example configuration of a driving assistance device according to an embodiment of the present disclosure; FIG. 3 is an explanatory diagram showing an example of bar list data for sound source data; FIG. 4 is an explanatory diagram showing an example of a data table in which sound source data selectable according to information on sensitivity of changes in playback method are set; FIG. 5 is an explanatory diagram showing an example of data conversion processing by the driving assistance device according to the present embodiment; FIG. 6 is an explanatory diagram showing an example of changing a threshold according to driver attributes according to the same embodiment; FIG. 7 is an explanatory diagram showing examples of behavior stability determination processing and sound source playback processing according to the same embodiment; FIG. 8 is a flowchart showing a main routine of control processing according to the same embodiment; FIG. 9 is a flowchart showing a main routine of control processing according to the same embodiment; FIG. 10 is a flowchart of a playback condition setting processing according to the same embodiment; FIG. 11 is a flowchart of behavior stability determination processing according to the same embodiment.

[0013] 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.

[0014] 1. Overview of Driving Assistance Device First, an overview of a driving assistance device according to an embodiment of the present disclosure will be described. While the vehicle is traveling, the driving assistance device acquires information indicating the vehicle's behavior, determines the vehicle's behavior stability based on the acquired information, and outputs a predetermined sound according to the determination result. Because the vehicle's behavior mainly reflects the driver's steering operation state, accelerator operation state, and brake operation state, the driver can intuitively recognize the evaluation of his or her own driving operation state in real time through auditory stimulation.

[0015] The driving assistance device according to this embodiment has a sound source data storage unit that stores a plurality of sound source data, each of which is made up of a plurality of measures or parts, and which is classified according to how easily the driver notices a change in the playback method of the sound source data. The driving assistance device selects the sound source data to be played back according to the driver's sensitivity to changes in the playback method, and when the vehicle behavior is stable, plays back the sound source data normally at a constant playback volume and a constant playback speed, progressing to the next measure or next part in a predetermined order, and when the vehicle behavior is unstable, plays back the sound source data by a playback method different from the normal playback.

[0016] This allows the playback method of the sound source data to change depending on the vehicle's behavioral stability, so the driver does not get the impression that their driving is being denied. Also, because sound source data that the driver can easily notice when the playback method is changed is selected, the driver can intuitively recognize the behavioral stability of the vehicle they are driving in real time through auditory stimulation.

[0017] "Noticeability of changes in the playback method of sound source data" refers to an index of the nature of music that indicates whether a listener will easily notice a change in one or more of the playback order of bars or parts, the playback volume, and the playback speed during playback of the sound source data. Sound source data that is easily noticeable when a change in playback method is made is, for example, music that is known to the driver of the vehicle. In this case, multiple sound source data are classified according to the number of times they have been played based on the playback history when the driver was driving the vehicle in the past, and stored in the sound source data storage unit.

[0018] However, the criteria for the ease of noticing a change in the playback method of the sound source data are not limited to the above example, and may be classified according to any criteria. For example, the multiple sound source data may be classified as music for which the more frequently a song is selected, the more likely it is that a change in the playback method will be noticed, based on data on the number of times the vehicle driver has selected the song at karaoke in the past. Alternatively, the multiple sound source data may be classified as music for which the more similar the lyrics, pitch, and rhythm of the multiple sound source data are to the previously selected songs, the more likely it is that a change in the playback method will be noticed.

[0019] In the embodiment described below, the degree of noticeability of a change in the playback method of sound source data is indicated in four stages: "hard to notice," "somewhat hard to notice," "somewhat easy to notice," and "easy to notice," and at least one song is assigned to each stage and stored in the sound source data storage unit. However, the method for setting the index of the degree of noticeability of a change in the playback method of sound source data is not particularly limited, and it may be indicated in multiple stages.

[0020] "Driver's sensitivity to changes in the playback method of sound source data" means an index that indicates whether the driver is a person who is likely to notice changes in one or more of the playback order of measures or parts, the playback volume, and the playback speed during playback of sound source data. In the embodiment described below, the driver's sensitivity to changes in the playback method of sound source data is indicated in four levels: "low," "slightly low," "slightly high," and "high." However, the method of setting the index is not particularly limited, and it may be indicated in multiple levels.

[0021] In the embodiment described below, "ease of noticing changes in the playback method of sound source data" may be referred to as "ease of noticing changes in playback method," and "sensitivity to changes in the playback method of sound source data" may be referred to as "sensitivity to changes in playback method."

[0022] 2. Configuration Example of Driving Assistance Device First, a configuration example of a driving assistance device 1 according to an embodiment of the present disclosure will be described with reference to Figures 1 and 2. Figure 1 is a schematic diagram showing a vehicle to which the driving assistance device 1 is applied, and Figure 2 is a block diagram showing an example of the configuration of the driving assistance device 1.

[0023] The driving assistance device 1 includes an information processing device 50. The information processing device 50 includes one or more processors such as a CPU (Central Processing Unit) and one or more memories such as a RAM (Random Access Memory) or a ROM (Read Only Memory) communicably connected to the processor. A part or all of the information processing device 50 may be configured with updatable firmware or the like, or may be a program module or the like that is executed in response to an instruction from the processor.

[0024] The information processing device 50 functions as a device that controls the operation of the driving assistance device 1 by having one or more processors execute a computer program. The computer program is a computer program that causes the processor to execute the operations described below that should be executed by the information processing device 50. The computer program executed by the processor may be recorded on a recording medium that functions as a storage unit (memory) 55 provided in the information processing device 50, or may be recorded on a recording medium built into the information processing device 50 or any recording medium that can be externally attached to the information processing device 50.

[0025] The recording medium for recording a computer program may be a magnetic medium such as a hard disk, a floppy disk, or a magnetic tape; an optical recording medium such as a CD-ROM (Compact Disk Read Only Memory), a DVD (Digital Versatile Disk), or a Blu-ray (registered trademark); a magneto-optical medium such as a floptical disk; a memory element such as a RAM or a ROM; a flash memory such as a USB (Universal Serial Bus) memory; or any other medium capable of storing a program.

[0026] The driving assistance device 1 also includes a vehicle behavior measurement device 11, an input device 13, a surrounding situation detection device 15, a position detection sensor 17, and an output device 21. The vehicle behavior measurement device 11, the input device 13, the surrounding situation detection device 15, the position detection sensor 17, and the output device 21 are communicably connected to an information processing device 50 via a communication bus such as a dedicated line or a CAN (Controller Area Network).

[0027] (2-1. Vehicle behavior measurement device) The vehicle behavior measurement device 11 is a device that measures information indicating the behavior of the vehicle. The vehicle behavior measurement device 11 includes, for example, at least one of a vehicle speed sensor, an acceleration sensor, and an angular velocity sensor. The vehicle speed sensor detects, for example, the rotational speed of the drive shaft of the vehicle. The acceleration sensor detects at least longitudinal acceleration, which is acceleration in the longitudinal direction of the vehicle body, and lateral acceleration, which is acceleration in the width direction of the vehicle. The acceleration sensor may also detect vertical acceleration, which is acceleration in the height direction of the vehicle body. The angular velocity sensor detects the rate of change of each of the rotation angle around an axis in the longitudinal direction of the vehicle body (roll angle), the rotation angle around an axis in the width direction of the vehicle body (pitch angle), and the rotation angle around an axis in the height direction of the vehicle body (yaw angle). The angular velocity sensor may be a yaw rate sensor that detects the rate of change of the yaw angle.

[0028] The data measured by the vehicle behavior measurement device 11 can change depending on the driver's steering, accelerator, and brake operations, and is transmitted as information indicating the vehicle behavior to the information processing device 50. The information processing device 50 is configured to be able to acquire the information measured by the vehicle behavior measurement device 11. The vehicle behavior measurement device 11 may include a sensor capable of measuring data reflecting the vehicle behavior, in addition to a vehicle speed sensor, an acceleration sensor, and an angular velocity sensor.

[0029] (2-2. Input Device) The input device 13 accepts user operation input and transmits it to the information processing device 50. The input device 13 may be, for example, a touch panel display or a dial-type operating device. Alternatively, the input device 13 may be a voice recognition device that accepts input by the voice of the occupant, or an image recognition device that accepts input by gesture.

[0030] In this embodiment, the input device 13 accepts input of information related to the driver's attributes. The information related to the driver's attributes is information related to the driver's driving skills, and includes, for example, at least one of the following information: the driver's age, the number of years since obtaining a license, driving frequency, the number of years since the last driving session, etc. Furthermore, other information that can be used to estimate the driver's driving skills may also be included. This information may be input in the form of a questionnaire in which the driver or the like answers questions presented by the information processing device 50, or data that has been determined or accumulated in advance may be input.

[0031] The input device 13 may also accept input of information about a sound desired as an output sound. For example, the input device 13 may be configured to allow the driver or the like to select a desired sound from among tones or types of sounds presented by the information processing device 50. Specifically, the type of instrument sound or sound effect to be output may be selectable. Data about the selected sound is stored in advance in the storage unit 55 of the information processing device 50, but the sound data may be updated or added by communicating with an external server or the like.

[0032] It should be noted that the input device 13 is not an essential component when the control conditions are not changed depending on the driver attributes or when the output sound is made unselectable.

[0033] (2-3. Surrounding Condition Detection Device) The surrounding condition detection device 15 detects the surrounding conditions of the vehicle. The surrounding condition detection device 15 is configured to include at least one of a stereo camera, a monocular camera, an ultrasonic sensor, a LiDAR (Light Detection and Ranging / Laser Imaging Detection and Ranging), and a radar sensor, for example. The driving assistance device 1 illustrated in FIG. 1 is equipped with a pair of left and right stereo cameras as the surrounding condition detection device 15.

[0034] The surrounding situation detection device 15 detects objects around the vehicle 10, such as other vehicles, bicycles, pedestrians, road signs, and other obstacles, based on the measured data, and calculates the distance to these objects, as well as their relative position and relative speed. The surrounding situation detection device 15 also detects the surrounding situation of the vehicle 10, such as road width and road shape, based on the measured data. Information on the surrounding situation detected by the surrounding situation detection device 15 is transmitted to the information processing device 50. The information processing device 50 is configured to be able to acquire the information detected by the surrounding situation detection device 15.

[0035] The surrounding condition detection device 15 may include other sensors capable of detecting the surrounding conditions of the vehicle 10 in addition to the stereo camera, monocular camera, ultrasonic sensor, LiDAR, and radar sensor. The surrounding condition detection device 15 may also include a raindrop sensor for detecting the amount of rainfall or an anemometer for detecting wind speed. Furthermore, the surrounding condition detection device 15 may include a communication device for communicably connecting the information processing device 50 to an external server that provides information on the surrounding conditions of the vehicle.

[0036] (2-4. Position Detection Sensor) The position detection sensor 17 receives positioning signals transmitted from satellites of a Global Navigation Satellite System (GNSS), such as the Global Positioning System (GPS), and detects the position of the vehicle. The position of the vehicle is acquired, for example, as data of latitude and longitude on the Earth. The position detection sensor 17 may receive positioning signals transmitted from another system, such as a quasi-zenith satellite system, instead of or in addition to the GNSS, and detect the position of the vehicle. Information on the vehicle position detected by the position detection sensor 17 is transmitted to the information processing device 50. The information processing device 50 is configured to acquire information on the vehicle position (position information) detected by the position detection sensor 17 and identify the position of the vehicle 10 on map data.

[0037] (2-5. Output Device) The output device 21 is a device that outputs a sound that can be recognized by the driver. The output device 21 may be a speaker provided in the vehicle, or may be a speaker dedicated to the driving assistance device 1. In this embodiment, the output device 21 is configured as a speaker system including a plurality of speakers 21a to 21d provided in the vehicle. The output of the output device 21 is controlled by the information processing device 50, and the output device 21 makes the driver aware of the vehicle's behavioral stability through auditory stimulation.

[0038] (2-6. Information Processing Device) The information processing device 50 includes a communication unit 51, a processing unit 53, a storage unit 55, a sound source data storage unit 57, and a map data storage unit 59. The processing unit 53 includes an acquisition unit 61, a sensitivity determination unit 63, a sound source selection unit 65, a data processing unit 67, a behavior stability determination unit 69, a playback condition setting unit 71, and a sound source playback processing unit 73. The processing unit 53 is a processor such as a CPU, and each of the acquisition unit 61, sensitivity determination unit 63, sound source selection unit 65, data processing unit 67, behavior stability determination unit 69, playback condition setting unit 71, and sound source playback processing unit 73 is a function realized by the processor executing a program. However, part of the acquisition unit 61, sensitivity determination unit 63, sound source selection unit 65, data processing unit 67, behavior stability determination unit 69, playback condition setting unit 71, and sound source playback processing unit 73 may be configured using analog circuits.

[0039] (Storage Unit) The storage unit 55 is configured to include one or more storage elements such as RAM or ROM. The storage unit 55 stores programs executed by the processing unit 53, various parameters used in executing the programs, acquired data, data of calculation results, etc. A part of the storage unit 55 is used as a work area for the processing unit 53.

[0040] (Sound Source Data Storage Unit) The sound source data storage unit 57 is composed of any recording medium communicably connected to the processing unit 53. The sound source data storage unit 57 stores a plurality of sound source data consisting of a plurality of measures or parts, and classified according to the ease with which changes in playback method are noticeable. The sound source data storage unit 57 also stores bar list data for each of the recorded sound source data.

[0041] FIG. 3 shows an example of bar list data. The sound source data shown in the bar list data shown in the figure consists of 14 bars (0 to 13). Each bar has a uniform length (time) of 10 seconds. The bar list data includes information on the start position (seconds) and end position (seconds) of each bar, with the start position of the sound source data as the reference (0 seconds). The sound source data storage unit 57 stores bar list data corresponding to each piece of recorded sound source data.

[0042] In this embodiment, the ease of noticing a change in playback method is classified into four levels: "hard to notice," "somewhat hard to notice," "somewhat easy to notice," and "easy to notice," and at least one song is assigned to each level of noticeability. In the following explanation, to facilitate understanding of the technology of the present disclosure, an example will be described in which sound source data of one song is recorded for each level of noticeability.

[0043] (Map Data Storage Unit) The map data storage unit 59 is a storage unit that stores map data. The map data includes not only information on topography, road type, road shape, buildings, locations of traffic signals, and pedestrian crossings, but also all kinds of traffic-related information such as road width, road gradient, number of lanes, speed limits, and traffic regulation signs. Various pieces of information included in the map data are associated with, for example, latitude and longitude position coordinates on the Earth. The map data storage unit 59 may be part of the storage unit 55 built into the information processing device 50, or may be realized by an on-board storage unit or an external server communicably connected to the information processing device 50.

[0044] (Communication Unit) The communication unit 51 is an interface for transmitting and receiving data and signals to and from the vehicle behavior measurement device 11, the input device 13, and the output device 21.

[0045] (Acquisition Unit) The acquisition unit 61 of the processing unit 53 acquires information transmitted from the vehicle behavior measurement device 11 and the input device 13 via the communication unit 51. The information acquired by the acquisition unit 61 includes information indicating the vehicle behavior output from the vehicle behavior measurement device 11. The acquisition unit 61 acquires information at a predetermined calculation period and stores the acquired information in the storage unit 55. The acquisition unit 61 also acquires information on the sensitivity of the vehicle's driver to changes in the playback method. In this embodiment, the acquisition unit 61 reads the information on the sensitivity of the driver to changes in the playback method determined by the sensitivity determination unit 63 and recorded in the storage unit 55.

[0046] (Sensitivity Determination Unit) The sensitivity determination unit 63 of the processing unit 53 determines the sensitivity of each driver to a change in the playback method. In this embodiment, the sensitivity determination unit 63 determines the degree to which a change has occurred in the vehicle's behavior stability before and after the sound source playback processing unit 73 changes the playback method of the sound source data. For example, the sensitivity determination unit 63 determines the sensitivity of the change in the playback method as the ratio of the number of times a change has occurred in the vehicle's behavior stability to the number of times the playback method of the sound source data has been changed. Since the purpose is to determine whether the driver has recognized the change in the playback method, the sensitivity determination unit 63 only needs to determine whether a change has occurred in the vehicle's behavior stability regardless of whether the vehicle's behavior stability has improved or deteriorated.

[0047] The sensitivity determination unit 63 associates information about the determination result with identification information about the driver and records it in the storage unit 55. For example, the sensitivity determination unit 63 identifies the driver based on driver information input by the driver via the input device 13, and records information about the determination result of the sensitivity to changes in the playback method in association with the identification information, such as an identification number, in the storage unit 55. If the vehicle is equipped with an in-vehicle camera that can capture an image of the driver, the sensitivity determination unit 63 may identify the driver based on features of the driver's face extracted from image information captured by the in-vehicle camera.

[0048] The method of determining the sensitivity to changes in the playback method by the sensitivity determination unit 63 is not limited to the above example, and any method may be used. Also, information on the results of a test conducted in advance by the driver to determine the sensitivity to changes in the playback method may be recorded in the storage unit 55. In this case, the sensitivity determination unit 63 may be omitted.

[0049] (Sound Source Selection Unit) The sound source selection unit 65 of the processing unit 53 selects sound source data to be reproduced from among a plurality of sound source data in accordance with the sensitivity of the driver to changes in the reproduction method. Specifically, the sound source selection unit 65 selects sound source data to be reproduced from one or more sound source data that are set selectable in accordance with the sensitivity, based on information on the sensitivity of the driver to changes in the reproduction method that is recorded in the storage unit 55.

[0050] 4 shows an example of a data table in which selectable sound source data is set according to information on sensitivity to changes in playback method. In the data table shown in FIG. 4, among songs A, B, C, and D assigned based on how easily users notice changes in playback method, selectable and unselectable songs are set according to each user's sensitivity to changes in playback method. Song A is a song in which changes in playback method are difficult to notice, song B is a song in which changes in playback method are somewhat difficult to notice, song C is a song in which changes in playback method are somewhat easy to notice, and song D is a song in which changes in playback method are easy to notice.

[0051] If the driver has a "high" sensitivity to changes in playback method, it is possible to select all of the sound source data for songs A to D. Also, if the driver has a "moderately high" sensitivity to changes in playback method, it is possible to select the sound source data for songs B to D other than song A, for which changes in playback method are difficult to notice. Also, if the driver has a "moderately low" sensitivity to changes in playback method, it is possible to select the sound source data for song C, for which changes in playback method are somewhat easy to notice, and song D, for which changes in playback method are easy to notice. Also, if the driver has a "low" sensitivity to changes in playback method, it is possible to select only the sound source data for song D, for which changes in playback method are easy to notice.

[0052] The sound source selection unit 65 selects sound source data to be reproduced based on the data table in accordance with the driver's sensitivity to changes in the reproduction method. This makes it possible to make the driver aware of changes in the reproduction method of the sound source data being reproduced, thereby increasing the reliability of the driver recognizing that the vehicle's behavior stability is decreasing due to the driver's driving. Therefore, the driver is made aware of driving operations that improve the vehicle's behavior stability, and the vehicle driving operation skill can be improved.

[0053] (Data Processing Unit) The data processing unit 67 of the processing unit 53 performs predetermined data processing on the information indicating the behavior of the vehicle acquired by the acquisition unit 61. Specifically, the data processing unit 67 performs at least one of smoothing processing, absolute value conversion processing, and differentiation processing on the acquired measurement data of the vehicle speed, acceleration (longitudinal acceleration, lateral acceleration, and vertical acceleration), or angular velocity (angular velocity of yaw angle, roll angle, and pitch angle), and calculates an index value that is a value indicating the magnitude of the behavior of the vehicle.

[0054] For example, the data processing unit 67 performs smoothing, absolute value conversion, and differentiation on the measurement data of the vehicle speed, acceleration, or angular velocity to calculate the absolute value of acceleration, the jerk of the absolute value of acceleration (jerk), or the jerk of the absolute value of angular velocity (angular acceleration). The calculated absolute values ​​of acceleration, angular velocity, jerk, or angular acceleration are larger the greater the vehicle behavior, and smaller the smaller the behavior, and are used as index values ​​indicating the magnitude of the vehicle behavior. In particular, by using the absolute value of the jerk or angular acceleration as the index value, the influence of changes in vehicle speed, acceleration, or angular velocity due to the trajectory of the road or the acceleration / deceleration of other vehicles is reduced, and changes in vehicle behavior due to the driver's driving operation state can be more accurately evaluated.

[0055] 5 is an explanatory diagram showing an example of data conversion processing by the data processing unit 67. Fig. 5 shows an example in which a lateral jerk value obtained from lateral acceleration measurement data detected by an acceleration sensor serving as one of the vehicle behavior measurement devices 11 is calculated as an index value indicating the magnitude of vehicle behavior. Specifically, the data processing unit 67 performs smoothing processing and absolute value conversion processing on the lateral acceleration measurement data detected by the acceleration sensor to convert it into absolute value data of lateral acceleration. Furthermore, the data processing unit 67 performs time differentiation processing on the absolute value data of lateral acceleration to convert the lateral acceleration measurement data into absolute value data of lateral jerk (lateral jerk) to use it as an index value.

[0056] The data processing unit 67 may calculate one index value using multiple data items selected from the acceleration, angular velocity, jerk, and absolute values ​​of angular acceleration. In this case, the data processing unit 67 may replace the values ​​of each piece of data used with the same index (for example, a value between 0 and 100), and use the average value of the values ​​obtained by replacing all the values ​​of the data used with the same index as the index value. In this case, each type of data may be weighted.

[0057] In this embodiment, an example will be described in which the data processing unit 67 acquires measurement data of the lateral acceleration detected by an acceleration sensor and calculates the lateral jerk as an index value indicating the magnitude of the vehicle behavior.

[0058] (Behavior Stability Determination Unit) The behavior stability determination unit 69 of the processing unit 53 executes a process for determining the behavior stability of the vehicle while the driver is driving the vehicle. In the present embodiment, the behavior stability determination unit 69 determines the behavior stability of the vehicle by comparing an index value indicating the magnitude of the vehicle's behavior, which is calculated while the vehicle is traveling, with a predetermined threshold. More specifically, in the present embodiment, the behavior stability determination unit 69 determines that the behavior stability of the vehicle is low when the number of times the index value exceeds the predetermined threshold reaches a predetermined reference number.

[0059] Furthermore, the behavior stability determination unit 69 generates an evaluation signal indicating the behavior stability determination result each time the vehicle travels for a predetermined period in a state where the behavior stability is high. That is, the behavior stability determination unit 69 generates an evaluation signal each time the predetermined period elapses without the number of times the index value has exceeded a predetermined threshold value reaching a predetermined reference number after starting to count the predetermined period. The count for the predetermined period is reset when the predetermined period elapses and then starts counting up again.

[0060] The predetermined period for determining whether the vehicle's behavior stability is being maintained at a high level is set to a time corresponding to each measure or part of the sound source data being used. That is, the behavior stability determination unit 69 refers to the measure list data of the sound source data selected by the sound source selection unit 65, and determines the end of the measure being played as the end of the predetermined period. If the measures of the sound source data are not of uniform length, the length of the predetermined period for determining whether the vehicle's behavior stability is being maintained at a high level also varies.

[0061] The behavior stability determination unit 69 may set a threshold value used to determine the behavior stability of the vehicle based on the level of the driving skill of each driver. The smaller the threshold value, the smaller the vehicle behavior needs to be to increase the behavior stability, and the driver can be guided to further stabilize the vehicle behavior. Instead of or in addition to the threshold value, the reference number of times used to determine the behavior stability of the vehicle may also be set based on the level of the driving skill of the driver.

[0062] For example, the behavior stability determination unit 69 sets the threshold to a smaller value as the driver's driving skill improves, and sets the threshold to a larger value as the driver's driving skill improves. Thus, for example, in the case of a driver with high driving skill and stable vehicle behavior, the threshold is set to a smaller value, and in order to be determined as having high behavior stability, the vehicle behavior needs to be more stable than that of a driver with low driving skill. Therefore, a driver with high driving skill can be guided to further stabilize the vehicle behavior. On the other hand, a driver with low driving skill can be guided to an appropriate level of behavior stability according to the driver's driving skill.

[0063] The behavior stability determination unit 69 may estimate the driver's driving skill based on at least one of information such as the driver's age, the number of years since obtaining a license, driving frequency, the number of years since the last drive, etc. In other words, if the driver's age is, for example, 70 years or older, the threshold is increased because the driver's driving skill is likely to have declined. Also, the longer the number of years since obtaining a license, the higher the driving skill is estimated to be, so the threshold is decreased. Also, the more frequently the driver drives, the higher the driving skill is estimated to be, so the threshold is decreased. Also, the longer the number of years since the last drive (number of blank years) is, the higher the driver's driving skill is likely to have declined, so the threshold is increased. These pieces of information on the driver's attributes may be information input via the input device 13.

[0064] Furthermore, the behavior stability determination unit 69 may estimate the driver's driving skill based on data on behavior stability during the driver's past driving. For example, the behavior stability determination unit 69 may use information on the number or frequency at which the index value calculated by the data processing unit 67 exceeded a threshold during the driver's past driving. In this case, the threshold is set to a smaller value because the driving skill is estimated to be higher the fewer the number or frequency at which the index value exceeded the threshold.

[0065] Furthermore, the behavior stability determination unit 69 may set conditions for data processing by the data processing unit 67 based on information about the driver's driving skill. For example, the behavior stability determination unit 69 may set the number of types of data to be used when the data processing unit 67 calculates an index value indicating the magnitude of the vehicle's behavior based on information about the driver's driving skill. Specifically, the behavior stability determination unit 69 increases the types of data to be used for calculating the index value as the driver's driving skill improves, and decreases the types of data to be used for calculating the index value as the driver's driving skill improves. As a result, for example, in the case of a driver with high driving skill and stable vehicle behavior, the behavior stability is determined based on more types of data, and the driver can be guided to further stabilize the vehicle's behavior. On the other hand, for a driver with low driving skill, the behavior stability is determined based on a relatively smaller number of data, and the driver can be guided to an appropriate level of behavior stability according to the driver's driving skill.

[0066] Even when the types of data used to calculate the index value are increased or decreased, regardless of the number of types of data used, the driver's steering operation state can be more easily evaluated by preferentially using data on lateral jerk or angular acceleration of yaw angle.Furthermore, the driver's accelerator operation and brake operation state can be more easily evaluated by preferentially using data on longitudinal jerk or angular acceleration of roll angle.

[0067] FIG. 6 is an explanatory diagram showing an example of a method for setting a threshold and a reference number of times based on information on the attributes of a driver whose driving skill can be estimated, and a method for increasing or decreasing the types of data used to calculate the index value. As shown in FIG. 6, when the driver's age is older than a predetermined age, the threshold is increased by a predetermined number, and the types of data used to calculate the index value are reduced. Furthermore, the longer the number of years since obtaining a driver's license, the smaller the threshold is, and the more types of data used to calculate the index value are. On the other hand, the shorter the number of years since obtaining a driver's license, the larger the threshold is, and the more types of data used to calculate the index value are reduced. Furthermore, the more frequently the driver drives, the smaller the threshold is, and the more types of data used to calculate the index value are. On the other hand, the less frequently the driver drives, the larger the threshold is, and the more types of data used to calculate the index value are reduced. Furthermore, the longer the number of years since the last driving (number of blank years) is, the larger the threshold is, and the more types of data used to calculate the index value are reduced.

[0068] For example, when evaluating behavior stability using one threshold, behavior stability determination unit 69 increases or decreases the threshold and increases or decreases the type of data based on information about the driver's attributes relative to a preset reference value of the threshold. For example, when calculating an index value from 0 to 100, the reference value of the threshold may be set to 50, and the threshold may be increased or decreased by multiplying it by a coefficient less than 1 or a coefficient greater than 1 based on each piece of information. Alternatively, when the data usable for evaluating behavior stability are set to 12 pieces of data, namely, longitudinal acceleration, lateral acceleration, vertical acceleration, angular velocity of yaw angle, angular velocity of pitch angle, angular velocity of roll angle, longitudinal jerk, lateral jerk, vertical jerk, angular acceleration of yaw angle, angular acceleration of pitch angle, and angular acceleration of roll angle, the number of pieces of data to be used may be set to five as the reference data, and the number of pieces of data to be used may be increased or decreased by one based on each piece of information.

[0069] Increasing or decreasing the threshold value can be replaced by increasing or decreasing the reference count. Alternatively, both the threshold value and the reference count may be changed. Note that the coefficients used when increasing or decreasing the threshold value or the reference count, and the coefficients used when increasing or decreasing the number of data types, may be constant regardless of the information, or may be weighted according to the information. However, the threshold value and the number of data types are increased or decreased within a range of a predetermined maximum value and a predetermined minimum value, respectively.

[0070] (Reproduction Condition Setting Unit) The reproduction condition setting unit 71 of the processing unit 53 executes a reproduction condition setting process that sets the reproduction volume and reproduction speed of the sound source data reproduced by the sound source reproduction processing unit 73. The driving assistance device 1 according to this embodiment is configured to make the driver recognize the vehicle's behavior stability by having the driver listen to the sound source data, so if the driver is in a situation where it is difficult for him to notice a change in the reproduction method of the sound source data, the effectiveness of the assistance process may be reduced. For this reason, if the surrounding conditions in which the vehicle is traveling are predetermined surrounding conditions where it is difficult for the driver to notice a change in the reproduction method, the reproduction condition setting unit 71 determines the reproduction volume or reproduction speed of the sound source data according to the surrounding conditions.

[0071] For example, the regeneration condition setting unit 71 determines whether a situation in which the driver's driving operation amount or driving operation items are large is a predetermined surrounding situation in which a change in the regeneration method is difficult to notice. Specifically, the regeneration condition setting unit 71 determines that a situation in which the driver's driving operation amount or steering operation items are large is a situation in which the driver's driving operation amount or steering operation items are large, based on information about the surrounding situation of the vehicle transmitted from the surrounding situation detection device 15.

[0072] Furthermore, the playback condition setting unit 71 determines whether the predetermined situation in which a change in the playback method is difficult to notice is one of the following: a situation in which there is a lot of noise around the vehicle, a situation in which the vehicle is running, a situation in which there is heavy rainfall, or a situation in which the wind speed is fast. Specifically, the playback condition setting unit 71 determines whether the situation is a situation in which there is a lot of noise around the vehicle, a situation in which the vehicle is running, a situation in which there is heavy rainfall, or a situation in which the wind speed is fast, based on the information on the situation around the vehicle transmitted from the surrounding situation detection device 15.

[0073] The playback condition setting unit 71 may estimate the surrounding conditions while the vehicle is traveling based on the vehicle position information detected by the position detection sensor 17 and the information recorded in the map data storage unit 59, in addition to the information on the surrounding conditions of the vehicle transmitted from the surrounding conditions detection device 15.

[0074] When the playback condition setting unit 71 determines that the situation around the vehicle corresponds to a predetermined situation, it increases the playback volume or speed of the sound source data being played. By increasing the playback volume, the sound source data becomes easier for the driver to hear, and the driver becomes more likely to notice a change in the playback method of the sound source data. Furthermore, by increasing the playback speed, the playback time of each measure becomes shorter, and the playback method changes more frequently, so the driver becomes more likely to notice a change in the playback method of the sound source data.

[0075] In order to prevent frequent changes in the playback volume or playback speed, which would make it difficult to distinguish between changes in playback conditions due to the vehicle's behavior stability and changes in the playback volume or playback speed due to changes in the surrounding conditions, a minimum time for maintaining the playback volume or playback speed is set. After setting the playback volume or playback speed, the playback condition setting unit 71 does not change the playback volume or playback speed due to changes in the surrounding conditions until the minimum time has elapsed.

[0076] (Sound Source Reproduction Processing Unit) The sound source reproduction processing unit 73 of the processing unit 53 executes sound source reproduction processing to progress to the next measure or next part in a predetermined order and reproduce the sound source data normally at a constant reproduction volume and a constant reproduction speed when the vehicle behavior is stable, and to reproduce the sound source data by a reproduction method different from the normal reproduction when the vehicle behavior is unstable. For example, as a reproduction method different from the normal reproduction when the vehicle behavior is unstable, the sound source reproduction processing unit 73 reproduces measures or parts different from the predetermined order, or reproduces the sound source data by changing the reproduction volume or reproduction speed.

[0077] As a result, while driving continues with a high level of vehicle behavior stability, the sound source data is normally played back at a constant playback volume and a constant playback speed, allowing the driver to listen to the sound source data comfortably and without any sense of discomfort. On the other hand, when the vehicle behavior stability decreases, the sound source data is played back in a different playback method from the normal playback, causing the driver to feel uncomfortable listening to the sound source data. This makes the driver conscious of trying to maintain a high level of vehicle behavior stability and increases their motivation to improve their driving skills.

[0078] The basic playback volume during normal playback may be set by the driver, for example, or may be a preset fixed value. The basic playback speed during normal playback may be a speed preset for each piece of sound source data. The playback volume and playback speed are changed by the playback condition setting unit 71 in accordance with the surrounding conditions of the vehicle, and are used as the playback volume and playback speed during normal playback.

[0079] In this embodiment, if the behavior stability determination unit 69 generates an evaluation signal at the end of each measure of the sound source data after the start of playback of the sound source data, the sound source playback processing unit 73 moves to the next measure and continues normal playback of the sound source data. On the other hand, if the behavior stability determination unit 69 does not generate an evaluation signal at the end of each measure of the sound source data, the sound source playback processing unit 73 plays the sound source data using a playback method different from normal playback.

[0080] However, the sound source playback processor 73 may also change at least one of the playback speed and playback volume when repeating the same measure. Alternatively, the sound source playback processor 73 may sequentially change the playback speed or playback volume if the vehicle behavior is not stable even after repeating the same measure a predetermined number of times. This gradually increases the sense of discomfort felt by the driver, making the driver aware that the vehicle behavior is becoming unstable for a longer period of time.

[0081] 7 is an explanatory diagram showing an example of the behavior stability determination process by the behavior stability determination unit 69 and the sound source reproduction process by the sound source reproduction processing unit 73. FIG. 7 shows an example in which the behavior stability determination unit 69 generates an evaluation signal each time the vehicle travels through each measure while the vehicle's behavior stability is high. "seg" in the diagram indicates a measure.

[0082] When the sound source playback processing unit 73 starts playing the sound source data at a predetermined playback speed and a playback volume set by the driver or the like, the behavior stability determination unit 69 determines whether the absolute value (index value) of the lateral jerk exceeds the threshold value thre_A while the vehicle is being driven. The behavior stability determination unit 69 counts the number of times that the index value exceeds the threshold value thre_A during the playback time T (seconds) of each measure segment. In the example shown in FIG. 7 , the reference number of times is set to four so that the behavior stability of the vehicle is determined to be low when the number of times that each index value exceeds the threshold value thre_A reaches four.

[0083] Since the playback time T (seconds) has elapsed without the index value exceeding the threshold thre_A in bar segment 0, the behavior stability determination unit 69 generates an evaluation signal at the end of bar segment 0. In response to the evaluation signal, the sound source playback processing unit 73 advances the playback bar to the next bar segment 1 while maintaining the playback speed. Unless the playback volume setting has been changed, the sound source playback processing unit 73 also maintains the playback volume.

[0084] Next, since the playback time T (seconds) has elapsed without the index value exceeding the threshold thre_A in measure segment 1, the behavior stability determination unit 69 generates an evaluation signal at the end of measure segment 1. In response to the generation of the evaluation signal, the sound source playback processing unit 73 advances the playback measure to the next measure segment 2 while maintaining the playback speed. Unless the playback volume setting has been changed, the sound source playback processing unit 73 also maintains the playback volume.

[0085] Next, in measure segment 2 of measure number 2, the index value exceeds the threshold value thre_A four or more times, so the behavior stability determination unit 69 does not generate an evaluation signal at the end of measure segment 2. When the playback time for measure segment 2 ends without generating an evaluation signal, the sound source playback processing unit 73 repeats playback of the same measure segment 2. While the playback speed is maintained in the example shown in FIG. 7 , the sound source playback processing unit 73 may change the playback speed. The sound source playback processing unit 73 may also change the playback volume.

[0086] Since the playback time T (seconds) for the second played measure seg2 has elapsed without the index value exceeding the threshold thre_A, the behavior stability determination unit 69 generates an evaluation signal at the end of measure seg2. In response to the generation of the evaluation signal, the sound source playback processing unit 73 advances the playback measure to the next measure seg3 while maintaining the playback speed. If the playback speed or playback volume has been changed, the sound source playback processing unit 73 returns the playback speed and playback volume to the speed or volume before the change.

[0087] Next, in measure segment 3 of measure number 3, the playback time T (seconds) has elapsed without the index value exceeding the threshold value thre_A, so the behavior stability determination unit 69 generates an evaluation signal at the end of measure segment 3. In response to the generation of the evaluation signal, the sound source playback processing unit 73 advances the playback measure to the next measure segment 4 while maintaining the playback speed. Unless the playback volume setting has been changed, the sound source playback processing unit 73 also maintains the playback volume.

[0088] In this way, after the start of playback of the sound source data, the behavior stability determination unit 69 determines the behavior stability of the vehicle for each played measure, and generates an evaluation signal when it determines that the vehicle's behavior has remained stable. Furthermore, during playback of the sound source data, if the behavior stability determination unit 69 generates an evaluation signal at the end of each measure, the sound source playback processing unit 73 advances the played measure to the next measure, but if no evaluation signal is generated, the sound source playback processing unit 73 repeatedly plays the same measure. This makes the driver aware of the need to maintain high vehicle behavior stability and increases his or her motivation to improve his or her driving skills.

[0089] 3. Processing Operation of Driving Assistance Device Up to this point, an example of the configuration of the driving assistance device 1 according to this embodiment has been described. Next, processing operation of the driving assistance device 1 will be described using a specific example.

[0090] 8 and 9 are flowcharts showing a processing routine performed by the processing unit 53 of the information processing device 50. First, the processing unit 53 determines whether to start execution of a process for presenting the driver's behavioral stability to the driver through auditory stimuli (hereinafter also referred to as "auditory stimulus output process") (step S11). The condition for starting execution of the auditory stimulus output process is not particularly limited. For example, if the auditory stimulus output process is constantly executed while the vehicle's driving system is activated, the processing unit 53 may determine to start execution of the auditory stimulus output process when the driving system is activated. Alternatively, the processing unit 53 may determine to start execution of the auditory stimulus output process when it is detected that the driver is seated in the driver's seat based on an output signal from a driver imaging camera or a load sensor installed in the driver's seat. Furthermore, if an occupant such as the driver can switch the execution of the auditory stimulus output process on and off, the processing unit 53 may determine to start execution of the auditory stimulus output process when the execution of the auditory stimulus output process is switched from off to on.

[0091] If it is determined that the auditory stimulus output process should not be started (S11 / No), the processing unit 53 repeatedly executes the determination process of step S11. If it is determined that the auditory stimulus output process should be started (S11 / Yes), the sound source selection unit 65 acquires information on the driver's sensitivity to changes in the playback method (step S13). For example, the sound source selection unit 65 identifies the driver based on the driver's facial features extracted from an image captured by an in-vehicle camera or driver information input by the driver via the input device 13, and reads out the information on the driver's sensitivity to changes in the playback method that is associated with the driver's identification information and stored in the storage unit 55. This determines whether the driver's sensitivity to changes in the playback method is "low," "slightly low," "slightly high," or "high."

[0092] Next, the sound source selection unit 65 selects sound source data to be played from the plurality of sound source data stored in the sound source data storage unit 57 according to the driver's sensitivity to changes in the playback method (step S15). Specifically, the sound source selection unit 65 refers to the data table shown in Fig. 4 and selects one of the selectable songs corresponding to the driver's sensitivity to changes in the playback method. Among the selectable songs, the sound source selection unit 65 may select the song that has been selected the least number of times in the past, may select randomly, or may select the song that resulted in the highest vehicle behavior stability when the auditory stimulation output process was previously performed.

[0093] Next, the sound source playback processor 73 refers to the bar list data (see FIG. 3) of the selected sound source data, and acquires the playback start position (time) and playback end position (time) of the bar to be played back from the sound source data (step S17). For example, before starting playback of the sound source data, the sound source playback processor 73 acquires information on the playback start position (0 seconds) and playback end position (10 seconds) of bar segment 0, which has bar number zero. After starting playback of the sound source data, the sound source playback processor 73 acquires information on the playback start position (0 seconds) and playback end position (10 seconds) of the bar segment to be played back next.

[0094] Next, the playback condition setting unit 71 sets the playback volume or playback speed of the sound source data according to the conditions around the vehicle (step S19). Figure 10 shows a flowchart of the playback condition setting process. First, the playback condition setting unit 71 determines whether a predetermined time has elapsed since the playback condition settings were changed in the previous playback condition setting process (step S41). The predetermined time is set to a value within a range of 60 to 300 seconds, for example, so that the playback conditions are not frequently changed according to the conditions around the vehicle.

[0095] If the regeneration condition setting unit 71 does not determine that a predetermined time has elapsed since the regeneration condition settings were changed in the previous regeneration condition setting process (S41 / No), it simply ends the regeneration condition setting process. On the other hand, if the regeneration condition setting unit 71 determines that a predetermined time has elapsed since the regeneration condition settings were changed in the previous regeneration condition setting process (S41 / Yes), it acquires information about the surrounding conditions of the vehicle (step S43). Specifically, the regeneration condition setting unit 71 acquires information about the surrounding conditions transmitted from the surrounding conditions detection device 15. Furthermore, the regeneration condition setting unit 71 acquires information about the surrounding conditions of the vehicle based on vehicle position information detected by the position detection sensor 17 and information recorded in the map data storage unit 59. Alternatively, the regeneration condition setting unit 71 may communicate with a server installed outside the vehicle to acquire information about the surrounding conditions of the vehicle.

[0096] Next, the playback condition setting unit 71 determines whether the situation around the vehicle is a predetermined situation in which a change in the playback method is unlikely to be noticed (step S45). If the playback condition setting unit 71 does not determine that the situation around the vehicle is a predetermined situation in which a change in the playback method is unlikely to be noticed (S45 / No), the playback condition setting unit 71 sets the correction values ​​for the playback volume and playback speed to zero (no correction) and ends the playback condition setting process.

[0097] On the other hand, if the playback condition setting unit 71 determines that the situation around the vehicle is a predetermined situation in which a change in the playback method is unlikely to be noticed (S45 / Yes), it sets a correction value to increase the playback volume or playback speed (step S47). The correction value to increase the playback volume or playback speed may be a correction coefficient for increasing the playback volume or the reference playback speed of the selected sound source data, or may be an additional correction value. After setting the correction value, the playback condition setting unit 71 ends the playback condition setting process.

[0098] Returning to FIG. 8, the sound source playback processing unit 73 plays back the sound source from the playback start position (time) of the selected sound source data at the set playback speed and playback volume (step S21).

[0099] Next, the behavior stability determination unit 69 executes a process for determining the behavior stability of the vehicle (step S23). Fig. 11 is a flowchart showing a routine for the behavior stability determination process. First, the behavior stability determination unit 69 resets a counter C that counts the number of times the behavior of the vehicle has become unstable (step S51).

[0100] Next, the acquisition unit 61 acquires data indicating the vehicle behavior transmitted from the vehicle behavior measurement device 11 (step S53). In this embodiment, the acquisition unit 61 acquires data on the vehicle speed, longitudinal acceleration, lateral acceleration, vertical acceleration, angular velocity of the roll angle, angular velocity of the pitch angle, and angular velocity of the yaw angle.

[0101] Next, the data processing unit 67 performs smoothing, absolute value conversion, and differentiation on each of the acquired data to calculate an index value that indicates the magnitude of the vehicle behavior (step S55). The data processing unit 67 replaces each of the data to be used with the same index (for example, a value between 0 and 100), and sets the average value of all the data to be used as the index value.

[0102] Next, the behavior stability determination unit 69 determines whether the calculated index value exceeds the threshold value thre_A (step S57). If the index value does not exceed the threshold value thre_A (S57 / No), the behavior stability determination unit 69 proceeds to step S61. If the index value exceeds the threshold value thre_A (S57 / Yes), the behavior stability determination unit 69 counts up (increments by 1) the counting counter C (step S59).

[0103] Next, the behavior stability determination unit 69 determines whether the currently played bar segment of the sound source data has ended (step S61). For example, the behavior stability determination unit 69 determines whether the playback position of the sound source data is the playback end position corresponding to the end position of the bar segment. If the behavior stability determination unit 69 does not determine that the currently played bar segment of the sound source data has ended (S61 / No), the process returns to step S53. On the other hand, if the behavior stability determination unit 69 determines that the currently played bar segment of the sound source data has ended (S61 / Yes), the process returns to step S53. If the behavior stability determination unit 69 determines that the currently played bar segment of the sound source data has ended (S61 / Yes), the process determines whether the counter value of the counting counter C has reached a reference number C0 (step S63).

[0104] If the counter value of the counting counter C has not reached the reference number C0 (S63 / No), the behavior stability determination unit 69 generates an evaluation signal (evaluation signal=1) indicating that the behavior of the vehicle was stable while the sound source data was being played back from the set playback start position to the playback end position (step S67).On the other hand, if the counter value of the counting counter C has reached the reference number C0 (S63 / Yes), the behavior stability determination unit 69 does not generate an evaluation signal (evaluation signal=0) (step S65) because the behavior of the vehicle was not stable while the sound source data was being played back from the set playback start position to the playback end position.

[0105] After the currently played bar segment ends and the behavior stability determination unit 69 performs the process of generating or not generating an evaluation signal, it returns to step S51, resets the counting counter C, and continues the behavior stability determination process.

[0106] 9 , while the behavior stability determination unit 69 is performing the behavior stability determination process, the sound source playback processing unit 73 determines whether the playback of the currently played bar segment has ended (step S25). The sound source playback processing unit 73 determines whether the playback position of the sound source data is the playback end position of the sound source data corresponding to the end position of the currently played bar segment. If the sound source playback processing unit 73 does not determine that the playback of the currently played bar segment has ended (S25 / No), the process returns to step S23. On the other hand, if the sound source playback processing unit 73 determines that the playback of the currently played bar segment has ended (S25 / Yes), the process returns to step S23. On the other hand, if the sound source playback processing unit 73 determines that the playback of the currently played bar segment has ended (S25 / Yes), the process determines whether the behavior stability determination unit 69 has generated an evaluation signal (step S27).

[0107] If the sound source playback processor 73 determines that an evaluation signal has been generated (Yes in S27), it advances the bar segment to be played back by one (Step S29). On the other hand, if the sound source playback processor 73 determines that an evaluation signal has not been generated (No in S27), it sets the bar segment to be played back to the same bar segment as the current setting (Step S31). This sets the next bar segment to be played back.

[0108] Next, the sound source playback processor 73 determines whether or not to terminate the auditory stimulation output process (step S33). If the sound source playback processor 73 does not determine to terminate the auditory stimulation output process (S33 / No), the process returns to step S17 and plays back the set bar. On the other hand, if the sound source playback processor 73 determines to terminate the auditory stimulation output process (S33 / Yes), the sensitivity determination unit 63 determines the sensitivity of the driver to changes in the playback method and updates the sensitivity data stored in the storage unit 55 (step S35).

[0109] For example, the sensitivity determination unit 63 determines the degree of change in the vehicle's behavior stability before and after the sound source playback processing unit 73 changes the playback method of the sound source data between the start and end of the auditory stimulation output process. The sensitivity determination unit 63 assigns the sensitivity of the playback method change to one of "low," "slightly low," "slightly high," or "high" depending on the ratio of the number of times the vehicle's behavior stability changed to the number of times the sound source data playback method was changed. The sensitivity determination unit 63 records the information on the determination result in the storage unit 55 in association with the driver's identification information.

[0110] The recorded information on the sensitivity to changes in the playback method is used the next time the auditory stimulation output process is performed. After the sensitivity determination unit 63 determines the driver's sensitivity to changes in the playback method, the processing unit 53 stops the auditory stimulation output process and ends this routine.

[0111] 4. Effects of the Present Embodiment As described above, the driving assistance device 1 according to the present embodiment acquires information indicating vehicle behavior while the vehicle is traveling, and if the vehicle behavior is stable, advances to the next measure or next part in a predetermined order and plays back the sound source data normally at a constant playback volume and a constant playback speed. If the vehicle behavior is unstable, the driving assistance device 1 plays back the sound source data using a playback method different from the normal playback. This allows the driver to recognize the vehicle's behavior stability in real time while driving. Furthermore, because the auditory stimulus does not include displayed or spoken text information, the driver can intuitively recognize the behavior stability through the auditory stimulus, thereby preventing a decline in attention. Furthermore, if the vehicle behavior is stable, advances to the next measure or next part in a predetermined order and plays back the sound source data normally at a constant playback volume and a constant playback speed. This motivates the driver to perform driving operations that will result in more stable vehicle behavior.

[0112] Furthermore, the driving assistance device 1 according to this embodiment acquires information on the driver's sensitivity to changes in the playback method, and selects sound source data to be played from among a plurality of sound source data according to the driver's sensitivity. Therefore, even if a driver has a low sensitivity to changes in the playback method, sound source data that is easy to notice when the playback method is changed can be selected, thereby increasing the reliability with which the driver is made aware of the vehicle behavior stability due to the driver's driving operation.

[0113] Furthermore, the driving assistance device 1 according to this embodiment compares an index value obtained from measurement data acquired while the vehicle is traveling with a predetermined threshold, and uses the number of times the index value exceeds the predetermined threshold as information on the vehicle behavior stability. This prevents the vehicle behavior stability from being determined to have deteriorated when the index value exceeds the threshold only once, and allows the vehicle behavior stability due to the driver's driving operation to be correctly evaluated.

[0114] Furthermore, in the driving assistance device 1 according to this embodiment, a threshold value or a reference number of times is set based on information on attributes related to the driver's driving skill. In particular, the higher the driver's driving skill, the lower the threshold value or the lower the reference number of times, and the lower the driver's driving skill, the higher the threshold value or the higher the reference number of times. Therefore, a driver with high driving skill can be guided to a driving operation state that further improves the vehicle's behavioral stability. Furthermore, a driver with low driving skill can be guided to a behavioral stability level appropriate for the driver's driving skill.

[0115] Furthermore, the driving assistance device 1 according to this embodiment plays back measures or parts different from the default order, or plays back sound source data with a different playback volume or playback speed, as a playback method different from normal playback when the vehicle behavior is unstable. This makes it possible to give the driver a sense of discomfort when the vehicle behavior is unstable, and motivates the driver to perform driving operations that will make the vehicle behavior more stable.

[0116] Furthermore, the driving assistance device 1 according to this embodiment determines whether the surrounding conditions in which the vehicle is traveling are predetermined conditions in which a change in the playback method is difficult to notice, and if the predetermined conditions are met, determines the playback volume or playback speed of the sound source data according to the surrounding conditions. Therefore, by changing the playback method of the sound source data, it is possible to increase the reliability of making the driver aware that the vehicle's behavior is unstable.

[0117] Furthermore, the driving assistance device 1 according to this embodiment determines whether the predetermined surrounding circumstances in which the change in the playback method is unlikely to be noticed are circumstances in which the driver has many driving operations or many driving operation items. Therefore, even in circumstances in which the driver's attention is likely to be directed to things other than the sound source data, it is possible to increase the reliability of making the driver aware that the vehicle's behavior is unstable.

[0118] Furthermore, the driving assistance device 1 according to this embodiment determines whether the predetermined situation in which a change in the playback method is difficult to notice is one of the following: a situation in which the sound around the vehicle is loud, a situation in which the vehicle is running is loud, a situation in which there is heavy rainfall, or a situation in which the wind speed is fast. Therefore, even in a situation in which the playback sound of the sound source data is easily hidden by sounds other than the sound source data, it is possible to increase the reliability of making the driver recognize that the behavior of the vehicle is unstable.

[0119] Although the preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the technology of the present disclosure is not limited to such examples. It is clear that a person skilled in the art of the technology to which the present disclosure pertains can conceive of various modified or altered examples 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.

[0120] For example, in each of the above embodiments, the vehicle behavior measurement device 11 of the driving assistance device 1 is a sensor or the like provided in the vehicle, the output device 21 is a speaker system provided in the vehicle, and the information processing device 50 is communicably connected to the vehicle behavior measurement device 11 and the output device 21 via a communication bus such as a CAN, but the technology of the present disclosure is not limited to this example. For example, the driving assistance device 1 may be configured as a mobile terminal device such as a smartphone. Configuring the driving assistance device 1 as a mobile terminal device makes it possible to use the auditory stimulation output processing regardless of the vehicle being driven, thereby increasing opportunities for the driver to improve their driving skills and improving their driving skills when driving different vehicle types.

[0121] In this case, a speaker mounted on the mobile terminal device may be used as the output device 21, or a vehicle speaker system connected to the mobile terminal device via wireless or wired communication means may be used as the output device 21. Furthermore, when the driving assistance device 1 is configured as a mobile terminal device, sensors such as an acceleration sensor mounted on the mobile terminal device may be used as the vehicle behavior measurement device 11. In this case, the information processing device 50 is configured to execute a process of converting the axial direction of the sensor mounted on the mobile terminal device to a predetermined direction so that the vehicle behavior can be accurately estimated using the sensor. For example, when the vehicle is stopped on a level road, the sensor mounted on the mobile terminal device may detect the direction of gravitational acceleration, record information on the deviation between the direction of gravitational acceleration and the axial direction of the sensor, and convert the axial direction of the sensor to a predetermined direction based on the information on the deviation. Alternatively, during the auditory stimulation output process, a process of guiding the mobile terminal device to be placed in the vehicle so that the axial direction of the sensor mounted on the mobile terminal device coincides with the longitudinal direction or lateral direction of the vehicle may be executed.

[0122] For example, in the above embodiment, an example has been described in which the information processing device of the driving assistance device is configured as a single device, but the technology of the present disclosure is not limited to such an example. Some or all of the functions of the information processing device 50 may be provided in an external server installed outside the vehicle.

[0123] In addition, the technology of the present disclosure can also be realized as a vehicle equipped with the driving assistance device described in the above embodiment, a driving assistance processing method using the driving assistance device, a computer program that causes a computer to function as the above driving assistance device, and a non-transitory tangible recording medium on which the computer program is recorded.

[0124] 1: Driving assistance device 10: Vehicle 11: Vehicle behavior measurement device 21: Output device 50: Information processing device 51: Communication unit 53: Processing unit 55: Storage unit 57: Sound source data storage unit 59: Map data storage unit 61: Acquisition unit 63: Sensitivity determination unit 65: Sound source selection unit 67: Data processing unit 69: Behavior stability determination unit 71: Reproduction condition setting unit 73: Sound source reproduction processing unit

Claims

1. A driving assistance device that presents the driving stability of a vehicle to a driver by means of an auditory stimulus, comprising: one or more processors; one or more memories communicably connected to the one or more processors; a sound source data storage unit communicably connected to the one or more processors and storing a plurality of sound source data composed of a plurality of musical phrases or parts, the plurality of sound source data being classified according to the ease of noticing that the playback method has been changed when the playback method of the sound source data is changed; the one or more processors are configured to: perform an acquisition process of acquiring information on the driver's sensitivity to the change in the playback method; perform a sound source selection process of selecting sound source data to be played back from among the plurality of sound source data according to the driver's sensitivity; perform a driving stability determination process of determining the driving stability based on a change in the behavior of the vehicle; perform a sound source playback process of, when the driving stability is higher than a predetermined standard, playing back the sound source data in a normal manner at a constant playback volume and a constant playback speed while proceeding to the next musical phrase or the next part in a predetermined order, and when the driving stability is lower than the predetermined standard, playing back the sound source data by a playback method different from the normal playback; A driving assistance device that executes the above processes.

2. The one or more processors are configured to: as the playback method different from the normal playback when the driving stability is lower than the predetermined standard, play back musical phrases or parts in an order different from the predetermined order, or change the playback volume or the playback speed to play back the sound source data. The driving assistance device according to Claim 1.

3. The one or more processors are configured to: determine whether the actual surrounding situation in which the vehicle is traveling is a predetermined surrounding situation in which it is difficult to notice that the playback method has been changed, and if it is the predetermined surrounding situation, determine the playback volume or the playback speed of the sound source data according to the surrounding situation. The driving assistance device according to Claim 1.

4. The one or more processors are configured to: determine whether the situation in which the driver has a large amount of driving operation or driving operation items is a predetermined surrounding situation in which it is difficult to notice that the playback method has been changed. The driving assistance device according to Claim 3.

5. The one or more processors are configured to: Determine whether any of the following situations, i.e., a situation where the sound around the vehicle is loud, a situation where the driving sound of the vehicle is loud, a situation where the rainfall is heavy, or a situation where the wind speed is high, is the predetermined situation in which it is difficult to notice that the playback method has been changed. The driving support device according to claim 3.

6. A driving support processing method for presenting the driving stability of a vehicle to a driver by auditory stimulation, wherein a computer acquires information on the driver's sensitivity to a change in the playback method of sound source data; selects sound source data to be played back from among the plurality of sound source data composed of a plurality of measures or parts, the plurality of sound source data being classified according to the ease of noticing that the playback method has been changed when the playback method of the sound source data is changed, according to the sensitivity of the driver; determines the driving stability based on a change in the behavior of the vehicle; when the driving stability is higher than a predetermined standard, proceeds to the next measure or the next part in a predetermined order and normally plays the sound source data at a constant playback volume and a constant playback speed, and when the driving stability is lower than the predetermined standard, plays the sound source data by a playback method different from the normal playback; A driving support processing method for executing the above.

7. On a computer, acquire information on the driver's sensitivity to a change in the playback method of sound source data; select sound source data to be played back from among the plurality of sound source data composed of a plurality of measures or parts, the plurality of sound source data being classified according to the ease of noticing that the playback method has been changed when the playback method of the sound source data is changed, according to the sensitivity of the driver; determine the driving stability based on a change in the behavior of the vehicle; A non-transitory tangible recording medium recording a computer program that causes the computer to perform the following: when the driving stability is higher than a predetermined standard, proceed to the next measure or the next part in a predetermined order and normally play the sound source data at a constant playback volume and a constant playback speed, and when the driving stability is lower than the predetermined standard, play the sound source data by a playback method different from the normal playback.

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