Driving assistance system and computer program

Abstract

To provide an operation support system capable of notifying a driver during driving of a steering state according to a method capable of suppressing degradation of attention power and thereby capable of making guidance to an appropriate steering behavior.SOLUTION: An operation support system, which supports steering operations by a driver, executes: acquiring information of scheduled tracks of a vehicle; determining an assumed steering angle of a steering wheel corresponding to the scheduled track; classifying a range of the steering angle of the steering wheel on the basis of the assumed steering angle into a plurality of angle areas and allocating sound for each angle area; and outputting the allocated sound according to the detected steering angle.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a driving assistance system and a computer program for guiding a driver to perform appropriate steering actions on a vehicle. [Background technology]

[0002] The level of vehicle driving operation varies depending on the driver. Various devices have been proposed to inform the driver of the vehicle's steering state. For example, Patent Document 1 proposes a driving assistance system that includes a steering angle detection means for detecting the steering angle of the steering wheel and a display means that is positioned visible to the driver and is capable of displaying the steering state around the center of rotation, where the display means displays steering angle information around the center of rotation in one-to-one correspondence with the steering angle and also displays steering direction information by moving the center of rotation. Patent Document 1 also proposes indicating the amount of steering of the steering wheel with a sound that changes in conjunction with the amount of steering, and controlling the sound so that, for example, the tone becomes higher as the amount of steering increases. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-062706 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the driving assistance system described in Patent Document 1, if the steering state is displayed to the driver while driving using an image display, there is a risk that the driver's attention to the surroundings of the vehicle will decrease when the driver visually checks it. Patent Document 1 also proposes indicating the steering amount of the steering wheel by using a sound that changes, but simply changing the sound does not allow the driver to know whether the steering action is appropriate.

[0005] 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 system and a computer program that can inform a driver of the steering state while driving in a manner that can prevent a decline in attention and guide the driver to appropriate steering behavior. [Means for solving the problem]

[0006] In order to solve the above problem, according to one aspect of the present disclosure, there is provided a driving assistance system that assists a driver in steering operation, the driving assistance system including one or more processors and one or more memories communicably connected to the one or more processors, wherein the processor acquires information on a predicted trajectory of the vehicle, calculates an expected steering angle of the steering wheel corresponding to the predicted trajectory, divides the range of the steering angle of the steering wheel into a plurality of angle regions based on the expected steering angle, assigns a sound to each angle region, and outputs the assigned sound according to the detected steering angle.

[0007] In order to solve the above problem, according to another aspect of the present disclosure, there is provided a computer program applicable to a driving assistance system that assists a driver in steering operation, the computer program causing one or more processors to execute processing including acquiring information on a predicted trajectory of a vehicle, determining an expected steering angle of the steering wheel corresponding to the predicted trajectory, dividing the range of the steering angle of the steering wheel into a plurality of angle regions based on the expected steering angle and assigning a sound to each angle region, and outputting the assigned sound according to the detected steering angle. [Effects of the Invention]

[0008] As described above, according to the present disclosure, a driver can be notified of the steering state while driving in a manner that can prevent a decline in attention, and can be guided to take appropriate steering action. [Brief explanation of the drawings]

[0009] [Figure 1]1 is a schematic diagram showing a vehicle to which a driving assistance system according to a first embodiment of the present disclosure is applied. [Figure 2] FIG. 2 is a block diagram showing a configuration example of a driving assistance system according to the embodiment. [Figure 3] 4 is a flowchart showing a main routine of auditory stimulation output processing by the driving assistance system according to the first embodiment. [Figure 4] FIG. 2 is an explanatory diagram showing an example of a sound allocation method according to the embodiment. [Figure 5] FIG. 10 is an explanatory diagram showing another example of a sound allocation method according to the embodiment. [Figure 6] FIG. 10 is an explanatory diagram showing another example of a sound allocation method according to the embodiment. [Figure 7] 3 is an explanatory diagram showing the operation of the driving assistance system according to the embodiment; FIG. [Figure 8] 3 is an explanatory diagram showing the operation of the driving assistance system according to the embodiment; FIG. [Figure 9] 3 is an explanatory diagram showing the operation of the driving assistance system according to the embodiment; FIG. [Figure 10] 3 is an explanatory diagram showing the operation of the driving assistance system according to the embodiment; FIG. [Figure 11] 3 is an explanatory diagram showing the operation of the driving assistance system according to the embodiment; FIG. [Figure 12] 3 is an explanatory diagram showing the operation of the driving assistance system according to the embodiment; FIG. [Figure 13] 10A and 10B are explanatory diagrams showing application examples of the sound allocation method according to the embodiment. [Figure 14] 10A and 10B are explanatory diagrams showing the effects of an application example of the sound allocation method according to the embodiment. [Figure 15] 10 is a flowchart showing a main routine of auditory stimulation output processing by a driving assistance system according to a second embodiment. [Figure 16] 10 is an explanatory diagram showing an example of a method for setting a reference scale when turning further according to the embodiment. FIG. [Figure 17] 10 is a flowchart showing an auditory output process when turning the steering wheel further according to the embodiment. [Figure 18] 10 is an explanatory diagram showing a method for adjusting the reference scale when turning further according to the embodiment. FIG. [Figure 19] 10 is an explanatory diagram showing a method for adjusting the reference scale when turning further according to the embodiment. FIG. [Figure 20] 10 is an explanatory diagram showing an example of a method for setting a reference scale during steering return according to the embodiment. FIG. [Figure 21] 10 is a flowchart showing an auditory output process during steering back according to the embodiment. [Figure 22] 10A and 10B are explanatory diagrams showing a method for adjusting the reference scale during steering return according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

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

[0011] <<1. First Embodiment>> <1-1. Driving assistance systems> First, a configuration example of a driving assistance system 10 according to a first embodiment of the present disclosure will be described with reference to Figures 1 and 2. Figure 1 is a schematic diagram showing a vehicle 1 equipped with the driving assistance system 10, and Figure 2 is a block diagram showing an example of the configuration of the driving assistance system 10.

[0012] The driving assistance system 10 includes a vehicle information acquisition device 11, a road shape information acquisition device 15, an output device 21, and an information processing device 50. The vehicle information acquisition device 11, the road shape information acquisition device 15, and the output device 21 are communicably connected to the information processing device 50 via a dedicated line, a communication bus such as a CAN (Controller Area Network), or a wireless communication means such as Bluetooth (registered trademark).

[0013] The vehicle information acquisition device 11 includes a steering angle sensor 12 and a vehicle speed sensor 13. The steering angle sensor 12 detects the rotation angle (steering angle) of the steering wheel 3. The vehicle speed sensor 13 detects the speed of the vehicle 1. In this embodiment, the vehicle information acquisition device 11 also includes a turn signal changeover switch 14. The turn signal changeover switch 14 is switched depending on the lighting state of the turn signal. The vehicle information acquisition device 11 may also include a driver imaging camera that images the driver. The information processing device 50 is configured to be able to receive signals output from the steering angle sensor 12, the vehicle speed sensor 13, and the turn signal changeover switch 14 or the driver imaging camera.

[0014] The road shape information acquisition device 15 includes a forward photographing camera 16 and a vehicle position detection sensor 17. The forward photographing camera 16 has an imaging element such as a CCD (Charged-Coupled Device) or a CMOS (Complementary Metal-Oxide-Semiconductor), and transmits generated image data to the information processing device 50. The forward photographing camera 16 may be a stereo camera including a pair of left and right cameras, or a monocular camera. Furthermore, the road shape information acquisition device 15 may include a LiDAR (Light Detection And Ranging) or radar sensor instead of or in addition to the forward photographing camera 16.

[0015] The vehicle position detection sensor 17 is a sensor used in a global navigation satellite system (GNSS) such as a global positioning system (GPS), receives satellite signals transmitted from satellites, and transmits the position information of the vehicle 1 contained in the satellite signals to the information processing device 50. Note that the vehicle position detection sensor 17 may include an antenna capable of receiving satellite signals from other satellite systems capable of identifying the position of the vehicle 1, instead of or in addition to the GPS antenna.

[0016] 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 system 10. 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 steering state through auditory stimulation.

[0017] The information processing device 50 is configured to include 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 executed by instructions from the processor.

[0018] The information processing device 50 functions as a device that outputs a sound according to the steering state by one or more processors executing a computer program. The computer program is a computer program that causes the processor to execute the operations to be performed by the information processing device 50, which will be described later. 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.

[0019] Recording media for recording computer programs may include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical recording media such as CD-ROMs (Compact Disk Read Only Memory), DVDs (Digital Versatile Disks), and Blu-ray (registered trademark), magneto-optical media such as floptical disks, memory elements such as RAMs and ROMs, and flash memories such as USB (Universal Serial Bus) memories, as well as other media capable of storing programs.

[0020] <1-2. Information processing devices> (1-2-1.Basic configuration) The information processing device 50 includes a communication unit 51, a processing unit 53, a storage unit 55, and a map data storage unit 57. The processing unit 53 includes an acquisition unit 61, a predicted trajectory calculation unit 63, an assumed steering angle calculation unit 65, a sound setting unit 67, and an output control unit 69. The processing unit 53 is configured by a processor such as a CPU, and the acquisition unit 61, the predicted trajectory calculation unit 63, the assumed steering angle calculation unit 65, the sound setting unit 67, and the output control unit 69 are functions realized by the processor executing a program. However, part of the acquisition unit 61, the predicted trajectory calculation unit 63, the assumed steering angle calculation unit 65, the sound setting unit 67, and the output control unit 69 may be configured by hardware such as an analog circuit or a logic circuit.

[0021] The communication unit 51 is an interface for communication between the processing unit 53 and the vehicle information acquisition device 11, the road shape information acquisition device 15, and the output device 21.

[0022] The storage unit 55 is configured to include one or more storage elements such as RAM or ROM, etc. The storage unit 55 stores the computer program executed by the processing unit 53, various parameters used for executing the computer program, acquired data, data of calculation results, etc.

[0023] The map data storage unit 57 is configured with a recording medium such as a hard disk, CD-ROM, or DVD. The map data storage unit 57 stores map data including at least road shape data. The road shape data includes information on road width, lanes, and curvature radius. The map data is configured so that a position on the map can be identified using a predetermined coordinate system, and the position of the vehicle 1 on the map data can be identified using information on a predetermined coordinate position included in the position data of the vehicle 1 transmitted from the vehicle position detection sensor 17.

[0024] Below, we will briefly explain the functions of the acquisition unit 61, predicted trajectory calculation unit 63, expected steering angle calculation unit 65, sound setting unit 67 and output control unit 69 of the processing unit 53, and then explain in detail the processing operations of each unit.

[0025] (1-2-2. Functional configuration) (Acquisition Department) The acquisition unit 61 acquires information transmitted from the vehicle information acquisition device 11 and the road shape information acquisition device 15 via the communication unit 51. The acquisition unit 61 acquires information at a predetermined calculation period and stores the acquired information in the memory unit 55.

[0026] (Predicted trajectory calculation section) The predicted trajectory calculation unit 63 calculates a predicted trajectory of the vehicle 1. The predicted trajectory calculation unit 63 identifies the shape of the road ahead in the traveling direction of the vehicle 1, and calculates a predicted trajectory of the vehicle 1 according to the road shape. In this embodiment, the predicted trajectory calculation unit 63 calculates the predicted trajectory of the vehicle 1 based on the position data of the vehicle 1 transmitted from the vehicle position detection sensor 17 and the map data recorded in the map data storage unit 57. In addition, the predicted trajectory calculation unit 63 calculates the shape of the road ahead of the vehicle 1 based on image data transmitted from the forward-facing imaging camera 16, and calculates the predicted trajectory of the vehicle 1.

[0027] Furthermore, based on the information on the predicted trajectory of the vehicle 1, the predicted trajectory calculation unit 63 calculates the radius of curvature of the turning section through which the vehicle 1 is scheduled to pass, the distance to the entrance of the turning section, and the distance from the entrance to the exit of the turning section. The "turning section" includes not only curved sections where the road shape is curved, but also driving sections when turning at an intersection.

[0028] The predicted trajectory calculation unit 63 may obtain the predicted trajectory of the vehicle 1 by either or both of calculating the predicted trajectory based on map data and calculating the predicted trajectory based on image data transmitted from the front-facing camera 16. For example, the predicted trajectory calculation unit 63 may obtain the predicted trajectory of the vehicle 1 by correcting the predicted trajectory obtained based on map data, for example, using information on obstacles identified based on the image data transmitted from the front-facing camera 16, the traveling position of the vehicle 1, and the like.

[0029] (Estimated steering angle calculation section) The expected steering angle calculation unit 65 calculates an expected steering angle of the steering wheel 3 corresponding to the predicted trajectory based on the information on the predicted trajectory of the vehicle 1 obtained by the predicted trajectory calculation unit 63. In addition, the expected steering angle calculation unit 65 calculates an expected maximum steering angle according to the radius of curvature of the turning section of the predicted trajectory.

[0030] (Sound settings section) The sound setting unit 67 executes a process of assigning sounds to the steering angle of the steering wheel 3 based on the information about the assumed steering angle calculated by the assumed steering angle calculation unit 65. Specifically, the sound setting unit 67 divides the range of the steering angle of the steering wheel 3 into a plurality of angle regions based on the assumed steering angle and assigns sounds to each angle region. At this time, the sound setting unit 67 assigns sounds so that the musical scale changes stepwise as the steering wheel 3 rotates in one direction when the steering wheel 3 is operated. In the first embodiment, the sound setting unit 67 assigns musical scales from a first standard scale to a second standard scale that are set in advance stepwise in the range from the standard steering angle to the assumed maximum steering angle.

[0031] (Output control section) The output control unit 69 converts the steering state of the steering wheel 3 by the driver into a sound based on the information about the sound allocation set by the sound setting unit 67 and the steering angle of the steering wheel 3 detected by the steering angle sensor 12, and executes a process of outputting the sound. Specifically, the output control unit 69 sets the sound assigned to the detected steering angle of the steering wheel 3 as the output sound, and controls the driving of the output device 21 to output the sound. The output sound may be, for example, the sound of a musical instrument such as a piano, organ, or violin, or may be a sound effect such as the sound of winning a medal, the sound of applause, or the sound of fireworks being launched. However, the output sound is not limited to these examples.

[0032] <1-3. Operation of driving assistance systems> So far, an example of the configuration of the driving assistance system 10 according to this embodiment has been described. Next, the operation of the driving assistance system 10 will be described using a specific example.

[0033] FIG. 3 is a flowchart showing a main routine of processing by the processing unit 53 of the information processing device 50 constituting the driving assistance system 10.

[0034] First, the processing unit 53 determines whether to start execution of a process for making the driver aware of the steering state of the steering wheel 3 through auditory stimulation (hereinafter also referred to as "auditory stimulation output process") (step S11). The condition for starting execution of the auditory stimulation output process is not particularly limited. For example, if the auditory stimulation 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 stimulation output process when the driving system is activated. Alternatively, the processing unit 53 may determine to start execution of the auditory stimulation 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 on / off the execution of the auditory stimulation output process, the processing unit 53 may determine to start execution of the auditory stimulation output process when the execution of the auditory stimulation output process is switched from off to on.

[0035] If it is not determined that the execution of the auditory stimulus output process should be started (S11 / No), the processing unit 53 repeatedly executes the determination process of step S11. If it is determined that the execution of the auditory stimulus output process should be started (S11 / Yes), the predicted trajectory calculation unit 63 of the processing unit 53 acquires road shape information (step S13). Specifically, the predicted trajectory calculation unit 63 identifies the position and orientation of the vehicle 1 on the map data based on the position data of the vehicle 1 transmitted from the vehicle position detection sensor 17. The predicted trajectory calculation unit 63 also acquires data on the road shape in the traveling direction of the vehicle 1, which is included in the map data. Alternatively, the predicted trajectory calculation unit 63 may calculate the road shape ahead of the vehicle 1 based on image data transmitted from the forward-facing imaging camera 16. In this case, the predicted trajectory calculation unit 63 executes a process of recognizing objects that can identify lane boundaries, such as white lines, curbs, guardrails, and sidewalls, and calculates the road shape.

[0036] Next, the predicted trajectory calculation unit 63 determines whether or not there is a curve section ahead in the traveling direction of the vehicle 1 (step S15). For example, if the radius of curvature of the acquired road shape is equal to or less than a predetermined threshold, the predicted trajectory calculation unit 63 determines that there is a curve section ahead in the traveling direction of the vehicle 1. The radius of curvature of the road shape may be included in the map data recorded in the map data storage unit 57, or may be calculated based on image data transmitted from the front-view photographing camera 16. The predetermined threshold may be set arbitrarily depending on the degree of the curve for which it is desired to make the driver aware of the steering state through an auditory stimulus.

[0037] If there is a curve section ahead in the traveling direction of the vehicle 1 (S15 / Yes), the predicted trajectory calculation unit 63 executes a process to calculate a predicted trajectory of the vehicle 1 (step S19). On the other hand, if there is no curve section ahead in the traveling direction of the vehicle 1 (S15 / No), the predicted trajectory calculation unit 63 determines whether or not the turn indicator is on based on the output signal of the turn indicator changeover switch (step S17). If the turn indicator is not on (S17 / No), the predicted trajectory calculation unit 63 returns to step S13 and repeats the process of each step described above. On the other hand, if the turn indicator is on (S17 / Yes), the predicted trajectory calculation unit 63 executes a process to calculate a predicted trajectory of the vehicle 1 (step S19).

[0038] In step S19, which is reached when there is a curve section ahead in the traveling direction (S15 / Yes) or when the turn signal is on (S17 / Yes), the predicted trajectory calculation unit 63 calculates the predicted trajectory of the vehicle 1. The predicted trajectory of the curve section may be calculated using any calculation method, such as using the center line in the width direction of the lane in which the vehicle 1 is traveling. Furthermore, the predicted trajectory when turning right or left may be an arc with a predetermined curvature radius that connects the center lines in the width direction of the lane before and after the turn. Furthermore, road shape data included in the map data may include data on the driving trajectory that is used as the predicted trajectory of the vehicle 1.

[0039] Furthermore, the predicted trajectory calculation unit 63 calculates a radius of curvature for each predetermined section of the calculated predicted trajectory. For example, the predicted trajectory calculation unit 63 calculates a radius of curvature of the predicted trajectory at each position of a passing point set for each predetermined section. The passing points set for each predetermined section may be set at a fixed distance, or may be set at a travel distance calculated by multiplying the vehicle speed of the vehicle 1 by a predetermined time.

[0040] Furthermore, the predicted trajectory calculation unit 63 defines the section from when the radius of curvature of the predicted trajectory becomes equal to or smaller than a predetermined threshold until it exceeds the predetermined threshold as a "turning travel section," and calculates the distance to the entrance of the turning travel section and the distance from the entrance to the exit of the identified turning travel section. The distance to the entrance of the turning travel section can be calculated as the length of the travel path from the position of the vehicle 1 to the entrance point of the turning travel section. Furthermore, the distance from the entrance to the exit of the turning travel section can be calculated as the length of the travel path from the entrance point of the turning travel section to the exit point. Each distance may be calculated as a distance specified on map data, or may be calculated as a distance specified by image data from the forward-viewing camera 16.

[0041] Next, the assumed steering angle calculation unit 65 calculates the assumed steering angle of the steering wheel 3 corresponding to the predicted trajectory based on the information on the predicted trajectory, and calculates the assumed maximum steering angle in each turning section (step S21). Specifically, the assumed steering angle calculation unit 65 determines the transition of the steering angle assumed when the vehicle 1 travels on the predicted trajectory by referring to data on the radius of curvature of the traveling trajectory with respect to the steering angle, which is set in advance based on the relationship between the steering angle of the steering wheel 3 and the steering angle of the steered wheels. Furthermore, the assumed steering angle calculation unit 65 determines the maximum steering angle assumed in each turning section from the data on the transition of the assumed steering angle.

[0042] Next, the sound setting unit 67 divides the range from the reference steering angle to the assumed maximum steering angle into a plurality of angle regions, and assigns preset scales from the first standard scale to the second standard scale in stages to the range from the reference steering angle to the assumed maximum steering angle (step S23). In this embodiment, when passing through each turning traveling section, the scales are assigned so that sounds from the first standard scale to the second standard scale are output from the time the vehicle 1 enters the turning traveling section until the steering angle becomes the assumed maximum steering angle, and sounds from the second standard scale to the first standard scale are output from the time the steering angle becomes the assumed maximum steering angle until the vehicle leaves the turning traveling section.

[0043] FIG. 4 is an explanatory diagram showing an example of assigning musical scales in which the first standard musical scale is set to "do" and the second standard musical scale is set to "do" one octave higher when the assumed maximum steering angle θz when the vehicle 1 travels through a right-curve section is 90 degrees. In the example shown in FIG. 4, the standard steering angle θ0 is set to the steering angle in a straight-ahead traveling state, i.e., 0 degree. The sound setting unit 67 divides the range from the standard steering angle θ0 (0 degree) to the assumed maximum steering angle θz (90 degrees) into eight angle regions, and assigns the musical scales "do," "re," "mi," "fa," "sol," "la," "si," and "do" in order from the standard steering angle θ0. As a result, the musical scales of "do," "re," "mi," "fa," "sol," "la," "si," and "do" are output so that the musical scale increases by one step from the time the vehicle 1 enters a turning traveling section until the steering angle reaches the assumed maximum steering angle θz. In addition, from the time the steering angle reaches the assumed maximum steering angle θz until the vehicle exits the turning section, the notes "Do," "Si," "La," "So," "Fa," "Mi," "Re," and "Do" are output in a manner that descends one musical scale step at a time.

[0044] If the scale is "Do," "Re," "Mi," "Fa," "So," "La," "Si," and "Do," many people can intuitively recognize the steering state in the range from the reference steering angle θ0 to the assumed maximum steering angle θz. Therefore, in this embodiment, regardless of the magnitude of the assumed maximum steering angle θz, the sound setting unit 67 divides the range from the reference steering angle θ0 to the assumed maximum steering angle θz into eight angle regions, and assigns the notes "Do," "Re," "Mi," "Fa," "So," "La," "Si," and "Do" in order from the reference steering angle θ0.

[0045] For example, Figures 5 and 6 show examples of scales assigned when the assumed maximum steering angle θz is 135 degrees and 70 degrees, respectively. Figure 5 is an example of traveling through a turning section with a larger curvature (smaller radius of curvature) than the example shown in Figure 4, and Figure 6 is an example of traveling through a turning section with a smaller curvature (larger radius of curvature) than the example shown in Figure 4. The larger the assumed maximum steering angle θz, the larger the angle range to which each scale is assigned, while the smaller the assumed maximum steering angle θz, the smaller the angle range to which each scale is assigned.

[0046] Note that the reference steering angle θ0 does not have to be 0 degrees, but by setting the reference steering angle θ0 to 0 degrees, it is possible to generate a sound of the first standard scale from the timing when the vehicle enters a turning section from a straight-ahead state or the timing when the turning direction is changed while traveling around an S-curve. On the other hand, when a curve section with a small curvature radius is recognized while traveling around a gentle curve with a large curvature radius, it is possible to set the scale by dividing the range from the steering angle immediately before entering the curve section to the assumed maximum steering angle into equal angle regions.

[0047] Next, the output control unit 69 determines whether the time it takes for the vehicle 1 to reach the entrance of the turning section is less than a predetermined threshold (step S25). This threshold determines the timing at which to start outputting a sound according to the steering state for each turning section, and may be set to any value including zero. The time it takes for the vehicle 1 to reach the entrance of the turning section can be calculated by dividing the distance from the vehicle 1 to the entrance of the turning section by the vehicle speed. The distance from the vehicle 1 to the entrance of the turning section may be calculated based on image data transmitted from the forward-facing camera 16, for example, or may be calculated based on map data and position information of the vehicle 1 identified by the vehicle position detection sensor 17.

[0048] If the time taken for the vehicle 1 to reach the entrance of the turning section is not less than the predetermined threshold (S25 / No), the output control unit 69 repeatedly determines whether the time taken for the vehicle 1 to reach the entrance of the turning section is less than the predetermined threshold. On the other hand, if the time taken for the vehicle 1 to reach the entrance of the turning section is less than the predetermined threshold (S25 / Yes), the output control unit 69 detects the steering angle θ based on the detection data transmitted from the steering angle sensor 12, and controls the output device 21 to output a sound assigned to an angle range including the detected steering angle θ (step S27).

[0049] Next, the output control unit 69 determines whether the vehicle 1 has passed through a turning section (step S29). For example, the output control unit 69 determines that the vehicle 1 has passed through a turning section when the steering angle θ of the steering wheel 3 becomes 0 degrees. The output control unit 69 may also determine that the vehicle 1 has passed through a turning section when a predetermined time has elapsed while the steering angle θ of the steering wheel 3 is maintained within a range of small steering angles centered on the reference steering angle θ0 (0 degrees). Alternatively, the output control unit 69 may determine that the vehicle 1 has passed through a turning section when the vehicle 1 reaches a section in which the radius of curvature of the predicted trajectory is equal to or greater than the predetermined threshold value used in step S15. When passing through successive curve sections such as an S-curve, the output control unit 69 may also determine that the vehicle 1 has passed through the previous curve section when the vehicle enters the next curve section.

[0050] If the vehicle 1 has not passed through a turning section (S29 / No), the output control unit 69 returns to step S23, where it repeats the process of detecting the steering angle θ and outputting the assigned sound. On the other hand, if the vehicle 1 has passed through a turning section (S29 / Yes), the processing unit 53 determines whether or not to end the auditory stimulus output process (step S31). For example, if the condition for determining in step S11 that the auditory stimulus output process should be started is not met, the processing unit 53 determines to end the auditory stimulus output process. If it is determined to end the auditory stimulus output process (S31 / Yes), the processing unit 53 stops the auditory stimulus output process and ends this routine. On the other hand, if it is not determined to end the auditory stimulus output process (S31 / No), the processing unit 53 returns to step S13 and continues the auditory stimulus output process.

[0051] <1-4. Effect> Next, the operation of the driving assistance system 10 according to this embodiment will be described with reference to Fig. 7 to Fig. 12. Fig. 7 to Fig. 12 all show examples in which the vehicle 1 passes through a right curve section in which the steering wheel 3 is turned further and then turned back at a constant steering angular velocity when the assumed maximum steering angle θz is 90 degrees and the steering operation is performed appropriately in accordance with the assumed steering angle for the entire turning section. Fig. 7 to Fig. 12 respectively show examples in which the driver performs an appropriate steering operation with the scales assigned as shown in Fig. 4 (Figs. 7 and 8), adds a corrective steering (Figs. 9 and 10), and turns the steering wheel 3 too far (Figs. 11 and 12).

[0052] As shown in FIGS. 7 and 8 , when the driver performs an appropriate steering operation, the sounds "Do," "Re," "Mi," "Fa," "So," "La," "Si," and "Do" are output in sequence while the steering wheel 3 is turned from the reference steering angle θ0 to the assumed maximum steering angle θz. Furthermore, without any interruption in the output sounds, the sounds "Do," "Si," "La," "So," "Fa," "Mi," "Re," and "Do" are output in sequence while the steering wheel 3 is turned back from the assumed maximum steering angle θz to the reference steering angle θ0. This allows the driver to intuitively recognize that the steering operation was appropriate when passing through a cornering section. Furthermore, the driver can intuitively recognize that the steering angle of the steering wheel 3 is approaching the assumed maximum steering angle θz while turning the steering wheel 3.

[0053] In contrast, as shown in FIGS. 9 and 10, when the driver applies a corrective steering, the sounds "Do," "Re," "Mi," "Fa," "So," "La," "Si," and "Do" are output in this order while the steering wheel 3 is turned from the reference steering angle θ0 to the assumed maximum steering angle θz. However, the speed at which the scale changes is faster than in the case of an appropriate steering operation (dashed line), and the sounds "Do," "Si," "La," "Si," and "Do" are output in succession in accordance with the corrective steering. Thereafter, the sounds "Do," "Si," "La," "So," "Fa," "Mi," "Re," and "Do" are output in this order while the steering wheel 3 is turned back from the assumed maximum steering angle θz to the reference steering angle θ0. Therefore, the driver can recognize that he or she has performed a corrective steering, and the driver can be made aware that the next time the steering operation will result in an appropriate change in the output sound.

[0054] 11 and 12, when the driver turns the steering wheel 3 too far, the notes "Do," "Re," "Mi," "Fa," "So," "La," "Si," and "Do" are output in this order while the steering wheel 3 is turned from the reference steering angle θ0 to the assumed maximum steering angle θz. However, the speed at which the notes change is faster than in the case of appropriate steering operation (dash-dotted line), and the output sound is interrupted thereafter while the steering angle exceeds the assumed maximum steering angle θz. Then, the notes "Do," "Si," "La," "So," "Fa," "Mi," "Re," and "Do" are output in this order while the steering wheel 3 is turned back from the assumed maximum steering angle θz to the reference steering angle θ0. Therefore, the driver can recognize that he / she has turned the steering wheel 3 too far, and the driver can be made aware of the need to prevent the output sound from being interrupted next time.

[0055] When assigning the musical scales, as shown in FIG. 13 , the angles of the angle regions obtained by dividing the range from the reference steering angle θ0 to the predetermined angle θx may be smaller than the angles of the angle regions obtained by dividing the range from the predetermined angle θx to the assumed maximum steering angle θz. In other words, the musical scales may be assigned so as to increase the sensitivity of the steering angle change indicated by the change in the musical scale when the steering wheel 3 starts to be turned further immediately after entering the turning section. In the example shown in FIG. 13 , the predetermined angle θx is 28 degrees, and the angular regions outputting the notes "Do," "Re," "Mi," and "Fa" are each set to 7 degrees, while the angular regions outputting the notes "So," "La," "Si," and "Do" are each set to 15.5 degrees. As a result, as shown in FIG. 14 , in order to operate the steering wheel 3 so that the musical scale changes at the same time intervals, the steering angular velocity needs to be gentle at the start of turning and the end of turning. Therefore, the driver is made aware of the need to gentle the steering operation at the start of turning or the end of turning. This makes it possible to realize a steering operation that more stabilizes the behavior of the vehicle 1.

[0056] <1-5. Effects of this embodiment> As described above, the driving assistance system 10 according to this embodiment calculates the expected steering angle of the steering wheel 3 corresponding to the predicted trajectory of the vehicle 1, divides the range of the steering angle of the steering wheel 3 into a plurality of angle regions based on the expected steering angle, assigns a sound to each angle region, and outputs the assigned sound according to the detected steering angle. This allows the driver to recognize the steering state of the steering wheel 3 in real time while driving. Furthermore, because the auditory stimulation does not include displayed or audio text information, the driver can intuitively recognize the steering state through the auditory stimulation, thereby preventing a decline in attention.

[0057] Furthermore, in the driving assistance system 10 according to this embodiment, the assumed maximum steering angle of the steering wheel is calculated, and sounds from a first standard scale to a second standard scale set in advance are assigned in stages in the range from the reference steering angle θ0 to the assumed maximum steering angle θz. Therefore, the driver can recognize how much the steering wheel 3 is turned relative to the assumed maximum steering angle, and can recognize that the steering wheel 3 has been turned too far. Furthermore, since sounds from the first standard scale to the second standard scale are output in stages as the steering wheel 3 is turned in one direction during operation, the driver can recognize that he or she has performed a corrective steering. This can motivate the driver to perform appropriate steering.

[0058] <<2. Second Embodiment>> Next, a driving assistance system according to a second embodiment of the present disclosure will be described. In the driving assistance system described in the first embodiment, an assumed maximum steering angle θz corresponding to the radius of curvature of the turning section of the predicted trajectory of the vehicle 1 is calculated, and notes from the first standard scale to the second standard scale are assigned in stages to the range from the reference steering angle θ0 to the assumed maximum steering angle θz. In contrast, in the driving assistance system according to the second embodiment, a reference rotation operation of the steering wheel corresponding to the predicted trajectory is set, and the interval of the angle region assigned so that the scale changes in stages when the steering angle changes in the rotation direction of the reference rotation operation of the steering wheel is made different from the interval of the angle region assigned so that the scale changes in stages when the steering angle changes in the direction opposite to the rotation direction of the reference rotation operation of the steering wheel.

[0059] The driving assistance system according to the second embodiment can be configured in the same manner as the driving assistance system 10 according to the first embodiment, except for the content of the sound allocation process. Below, among the processing operations of the driving assistance system according to this embodiment, those points that differ from the processing operations of the driving assistance system according to the first embodiment will be described.

[0060] FIG. 15 is a flowchart showing a main routine of processing by the processing unit 53 of the information processing device 50 that constitutes the driving assistance system 10 according to this embodiment.

[0061] First, after the processing unit 53 determines to start execution of the auditory stimulation output process, the predicted trajectory calculation unit 63 acquires road shape information and determines whether or not there is a turning section ahead in the traveling direction of the vehicle 1 (steps S41 to S47). Furthermore, if it is determined that there is a turning section ahead in the traveling direction of the vehicle 1 (S45 / Yes, S47 / Yes), the predicted trajectory calculation unit 63 calculates a predicted trajectory for the vehicle 1 while passing through the turning section (step S49). The processing up to this point, from step S41 to step S49, may be executed in the same manner as the processing from step S11 to step S19 in the flowchart shown in FIG. 3.

[0062] Next, the assumed steering angle calculation unit 65 calculates an assumed steering angle of the steering wheel 3 corresponding to the predicted trajectory based on the information on the predicted trajectory (step S51). Specifically, the assumed steering angle calculation unit 65 refers to data on the radius of curvature of the traveling trajectory with respect to the steering angle, which is set in advance based on the relationship between the steering angle of the steering wheel 3 and the steering angle of the steered wheels, and determines the transition of the steering angle that is assumed when the vehicle 1 travels through the turning traveling section.

[0063] Next, the assumed steering angle calculation unit 65 sets a reference rotation operation based on the transition of the calculated assumed steering angle (step S53). The "reference rotation operation" is data that sets, in time series, the timing at which the steering wheel 3 starts to be turned and the timing at which the steering wheel 3 starts to be turned back in accordance with the assumed steering angle, and the rotation direction of the steering wheel 3 while the vehicle 1 is traveling in a turning section. For example, when traveling in a curve section, the timing and rotation direction (increased steering direction) at which the steering wheel 3 starts to be turned in the turning direction of the curve, and the timing and rotation direction (returning direction) at which the steering wheel 3 starts to be turned back are set. In this embodiment, the reference rotation operation further includes information on the assumed maximum steering angle in the turning section.

[0064] Next, the sound setting unit 67 sets the current steering angle of the steering wheel 3 as a rotation start steering angle (reference steering angle) θ0, and divides the range of the steering angle in the rotation direction of the reference rotation operation, which turns the steering wheel 3 from the reference steering angle θ0 to an assumed maximum steering angle θz, into a plurality of angle regions, and assigns a standard musical scale for turning the steering wheel 3 so that the musical scale changes stepwise as the steering angle changes in the rotation direction (step S55). The standard musical scale for turning the steering wheel 3 also includes a musical scale that is assigned by dividing a predetermined range of the steering angle from the reference steering angle θ0 in the direction opposite to the rotation direction of the reference rotation operation into a plurality of angle regions, and changing the musical scale as the steering angle changes in the opposite direction. When setting the standard musical scale for turning the steering wheel 3, the sound setting unit 67 makes the interval between the angle regions set in the rotation direction of the reference rotation operation different from the interval between the angle regions set in the direction opposite to the rotation direction of the reference rotation operation.

[0065] FIG. 16 is an explanatory diagram showing a standard musical scale for further steering that is set when the assumed maximum steering angle θz is 90 degrees when the vehicle 1 travels through a section that curves to the right. In the example shown in FIG. 16, the range from the reference steering angle θ0 (0 degrees) to the assumed maximum steering angle θz (90 degrees) is divided into four angle regions, and the musical scales of "Do," "Re," "Mi," and "Fa" are assigned in order from the reference steering angle θ0 side. In addition, a predetermined range from the reference steering angle θ0 (0 degrees) in the direction opposite to the rotation direction of the reference rotation operation is divided into three angle regions, and the musical scales of "Si," "La," and "So" are assigned in order from the reference steering angle θ0 side. The interval between the angle regions in the range from the reference steering angle θ0 (0 degrees) to the assumed maximum steering angle θz (90 degrees) is 22.5 degrees, while the interval between the angle regions in the predetermined range in the opposite direction is 10 degrees.

[0066] As a result, when the steering angle changes in accordance with the reference rotation operation after the vehicle 1 enters a turning section, sounds of "do," "re," "mi," and "fa" are output so that the musical scale rises by one step until the steering angle reaches the assumed maximum steering angle θz. Also, if an unnecessary operation of turning the steering wheel 3 in the opposite direction is performed at the timing of entering the turning section, sounds of "si," "la," and "sol" are output so that the musical scale falls by one step. And, because the interval between the angle regions set in the opposite direction to the rotation direction of the reference rotation operation is smaller than the interval between the angle regions set in the rotation direction of the reference rotation operation, sensitivity to changes in sound when the steering wheel 3 is rotated in the opposite direction is higher.

[0067] The number of angle regions dividing the range from the reference steering angle θ0 to the assumed maximum steering angle θz is not limited to four. The number of divided angle regions may be set to any number, and the interval (angle) between each angle region may be set in advance. Furthermore, the range to which the sound is assigned in the direction opposite to the rotation direction of the reference rotation operation from the reference steering angle θ0 and the number of angle regions dividing this range are not particularly limited, but by making the interval between each angle region in this range smaller than the interval between the angle regions dividing the range from the reference steering angle θ0 to the assumed maximum steering angle θz, it becomes easier to recognize that the driver has turned the steering wheel 3 in the direction opposite to the rotation direction of the reference rotation operation.

[0068] Furthermore, the reference steering angle θ0 does not have to be 0 degrees, and the steering angle of the steering wheel 3 when the turning section is recognized may be set as the reference steering angle θ0. This allows the range from the steering angle immediately before entering the turning section to the assumed maximum steering angle θz to be divided into equal angle regions and the scale can be set.

[0069] After the reference tone scale for further turning is set before the vehicle 1 enters the turning section, the output control unit 69 executes the auditory output process for further turning (step S57). Figure 17 is a flowchart showing the auditory output process for further turning.

[0070] The output control unit 69 detects the steering angle θ based on the detection data transmitted from the steering angle sensor 12, and controls the output device 21 to output a sound assigned to an angle range including the detected steering angle θ (step S71). Next, the output control unit 69 determines whether the scale of the output sound has increased from the scale of the output sound in the previous routine (step S73). If the scale of the output sound has not increased (S73 / No), the output control unit 69 returns to step S71 and repeats the process of detecting the steering angle θ and outputting the assigned sound.

[0071] On the other hand, if the scale of the output sound has been raised (S73 / Yes), the sound setting unit 67 adjusts the allocation of the standard scale when the steering wheel 3 is turned further (step S75). Here, as the steering wheel 3 is turned further in accordance with the standard rotation operation, the intervals of the angle areas set in the direction opposite to the rotation direction of the standard rotation operation are adjusted.

[0072] 18 and 19 are explanatory diagrams showing a method for adjusting the reference scale when turning further. If the steering wheel 3 is turned to the right by 30 degrees from a state in which the standard musical scale for further steering is set as shown in FIG. 16, the musical scale of the output sound rises from "C" to "D". In this case, as shown in FIG. 18, the sound setting unit 67 makes the intervals of all angle regions located in the direction opposite to the further steering direction from the angle region including the current steering angle θ smaller than the intervals of angle regions located on the further steering side. Specifically, in the example shown in FIG. 18, the intervals of the angle regions to which the musical scale for "C" was assigned are changed from 22.5 degrees to 10 degrees.

[0073] Furthermore, if the steering wheel 3 is turned to the right by 80 degrees, the note of the output sound increases to "Fa." In this case, as shown in FIG. 19, the sound setting unit 67 makes the intervals between all angle regions located in the direction opposite to the further steering direction from the angle region including the current steering angle θ smaller than the intervals between angle regions located in the further steering direction. Specifically, in the example shown in FIG. 19, the intervals between the angle regions to which the notes "Re" and "Mi" were assigned are changed from 22.5 degrees to 10 degrees.

[0074] As a result, when the driver performs a steering correction while traveling in a turning section, the tone of the output sound is lowered, allowing the driver to intuitively recognize the steering correction.

[0075] Next, the output control unit 69 determines whether the vehicle 1 has passed through a position or range where the steering angle θ is the assumed maximum steering angle θz (step S77). If the vehicle 1 has not passed through a position or range where the steering angle θ is the assumed maximum steering angle θz (S77 / No), the output control unit 69 returns to step S71 and repeats the processing of each step described above. On the other hand, if the vehicle 1 has passed through a position or range where the steering angle θ is the assumed maximum steering angle θz (S77 / Yes), the output control unit 69 ends the auditory stimulation output processing when steering further.

[0076] Returning to FIG. 15 , next, the sound setting unit 67 divides the range of the steering angle in the rotation direction of the reference rotation operation, which is steering back from the assumed maximum steering angle θz to the reference steering angle θ0, into a plurality of angle regions, and assigns a standard steering scale for steering back so that the scale changes stepwise when the steering angle changes in that rotation direction (step S59). The standard steering scale for steering back also includes a scale that is assigned by dividing a predetermined range of the steering angle from the assumed maximum steering angle θz in the direction opposite to the rotation direction of the reference rotation operation (the direction of further steering) into a plurality of angle regions, and changing the scale when the steering angle changes in that opposite direction. When setting the standard steering scale for steering back, the sound setting unit 67 makes the spacing of the angle regions set in the rotation direction of the reference rotation operation different from the spacing of the angle regions set in the direction opposite to the rotation direction of the reference rotation operation.

[0077] FIG. 20 is an explanatory diagram showing the standard musical scale for steering back that is set when the assumed maximum steering angle θz is 90 degrees when the vehicle 1 is traveling through a section that curves to the right. In the example shown in FIG. 20, the range from the assumed maximum steering angle θz (90 degrees) to the reference steering angle θ0 (0 degrees) is divided into four angle regions, and the musical scales of "Fa," "Mi," "Re," and "Do" are assigned in order from the assumed maximum steering angle θz side. The musical scale assigned to the range from the assumed maximum steering angle θz (90 degrees) to the reference steering angle θ0 (0 degrees) is the same as the standard musical scale for turning further that is shown in FIG. 16. In addition, a predetermined range from the assumed maximum steering angle θz (90 degrees) in the direction opposite to the rotation direction of the reference rotation operation is divided into three angle regions, and the musical scales of "So," "La," and "Si" are assigned in order from the assumed maximum steering angle θz side. The interval between the angle regions ranging from the assumed maximum steering angle θz (90 degrees) to the reference steering angle θ0 (0 degrees) is 22.5 degrees, while the interval between the angle regions in the predetermined range in the opposite direction is 10 degrees.

[0078] As a result, when the steering angle changes in accordance with the reference rotation operation when the steering wheel 3 is turned back, the notes "Fa," "Mi," "Re," and "Do" are output so that the musical scale descends by one step until the steering angle reaches the reference steering angle θ0. Furthermore, if the steering wheel 3 is turned further at the timing when the steering wheel starts to be turned back, the notes "So," "La," and "Si" are output so that the musical scale ascends by one step. Furthermore, because the interval between the angle regions set in the opposite direction to the rotation direction of the reference rotation operation is smaller than the interval between the angle regions set in the rotation direction of the reference rotation operation, sensitivity to changes in the sound when the steering wheel 3 is rotated in the opposite direction is higher.

[0079] The number of angle regions dividing the range from the assumed maximum steering angle θz to the reference steering angle θ0 is not limited to four. The number of divided angle regions may be set to any number, and the interval (angle) between each angle region may be set in advance. Furthermore, the range to which the sound is assigned in the direction opposite to the rotation direction of the reference rotation operation from the assumed maximum steering angle θz and the number of angle regions dividing this range are not particularly limited, but by making the interval between each angle region in this range smaller than the interval between the angle regions dividing the range from the assumed maximum steering angle θz to the reference steering angle θ0, it becomes easier to recognize that the driver has turned the steering wheel 3 in the direction opposite to the rotation direction of the reference rotation operation.

[0080] Furthermore, the reference steering angle θ0 does not have to be 0 degrees, and if the assumed steering angle at the exit of the turning section is specified, the assumed steering angle may be set as the reference steering angle θ0. This allows the range from the assumed maximum steering angle θz to the steering angle immediately after exiting the turning section to be divided into equal angle regions and the scale set.

[0081] After the standard tone scale for steering back is set, the output control unit 69 executes auditory output processing for steering back (step S61). Figure 21 is a flowchart showing the auditory output processing for steering back.

[0082] The output control unit 69 detects the steering angle θ based on the detection data transmitted from the steering angle sensor 12, and controls the output device 21 to output a sound assigned to an angle range including the detected steering angle θ (step S81). Next, the output control unit 69 determines whether the pitch of the output sound has dropped from the pitch of the output sound in the previous routine (step S83). If the pitch of the output sound has not dropped (S83 / No), the output control unit 69 returns to step S81 and repeats the process of detecting the steering angle θ and outputting the assigned sound.

[0083] On the other hand, if the pitch of the output sound has dropped (S83 / Yes), the sound setting unit 67 adjusts the allocation of the standard pitch when steering back (step S85). Here, as the steering wheel 3 is turned back in accordance with the standard rotation operation, the intervals of the angle regions set in the direction opposite to the rotation direction of the standard rotation operation are adjusted.

[0084] FIG. 22 is an explanatory diagram showing a method for adjusting the reference scale when turning back. If the steering wheel 3 is returned to the right to a position of 35 degrees from a state in which the standard musical scale for steering back is set as shown in Fig. 20, the musical scale of the output sound will gradually decrease from "Fa" to "Re." In this case, as shown in Fig. 22, the sound setting unit 67 makes the intervals between all angle regions located in the opposite direction to the steering back direction from the angle region including the current steering angle θ smaller than the intervals between angle regions located on the steering back side. Specifically, in the example shown in Fig. 22, the intervals between the angle regions to which the notes "Mi" and "Fa" were assigned are changed from 22.5 degrees to 10 degrees.

[0085] As a result, when the driver makes a corrective steering while turning the steering wheel 3 back toward the exit of the turning section, the tone of the output sound rises, allowing the driver to intuitively recognize the corrective steering.

[0086] Next, the output control unit 69 determines whether the vehicle 1 has passed through a position or range where the steering angle θ becomes the reference steering angle θ0 (step S87). If the vehicle 1 has not passed through a position or range where the steering angle θ becomes the reference steering angle θ0 (S87 / No), the output control unit 69 returns to step S81 and repeats the processing of each step described above. On the other hand, if the vehicle 1 has passed through a position or range where the steering angle θ becomes the reference steering angle θ0 (S87 / Yes), the output control unit 69 ends the steering-back auditory stimulation output processing.

[0087] After the steering-back auditory stimulus output process is completed, the processing unit 53 determines whether or not to terminate the auditory stimulus output process (step S63). For example, if the condition for determining in step S41 that the auditory stimulus output process should be started is not met, the processing unit 53 determines to terminate the auditory stimulus output process. If it is determined to terminate the auditory stimulus output process (S63 / Yes), the processing unit 53 stops the auditory stimulus output process and terminates this routine. On the other hand, if it is not determined to terminate the auditory stimulus output process (S63 / No), the processing unit 53 returns to step S43 and continues the auditory stimulus output process.

[0088] As described above, the driving assistance system 10 according to this embodiment calculates the expected steering angle of the steering wheel 3 corresponding to the predicted trajectory of the vehicle 1, divides the range of the steering angle of the steering wheel 3 into a plurality of angle regions based on the expected steering angle, assigns a sound to each angle region, and outputs the assigned sound according to the detected steering angle. This allows the driver to recognize the steering state of the steering wheel 3 in real time while driving. Furthermore, because the auditory stimulation does not include displayed or audio text information, the driver can intuitively recognize the steering state through the auditory stimulation, thereby preventing a decline in attention.

[0089] Furthermore, in the driving assistance system 10 according to this embodiment, when the vehicle 1 enters a turning section, a standard steering scale is set in which sounds with gradually ascending tones are assigned to a range from the reference steering angle θ0 to the assumed maximum steering angle θz in the rotation direction of the reference rotation operation, and sounds with gradually descending tones are assigned to a predetermined range from the reference steering angle θ0 in the opposite direction. Furthermore, while the steering wheel 3 is being turned further, the standard steering scale is adjusted so that the interval between angle regions in the direction opposite to the turning further direction, relative to the angle region including the steering angle θ at that time, is smaller than the interval between angle regions in the turning further direction. Therefore, if a corrective steering operation is performed while the steering wheel 3 is being turned further, the driver can intuitively recognize that the corrective steering has been performed.

[0090] Furthermore, in the driving assistance system 10 according to this embodiment, when the vehicle 1 heads toward the exit of a turning section, a standard steering scale is set in which sounds with gradually descending tones are assigned to a range from the assumed maximum steering angle θz to the reference steering angle θ0 in the rotation direction of the reference rotation operation, and sounds with gradually ascending tones are assigned to a predetermined range from the assumed maximum steering angle θz in the opposite direction. Furthermore, while the steering wheel 3 is being turned back, the standard steering scale is adjusted so that the interval between angle regions in the direction opposite to the turning back direction, which are smaller than the interval between angle regions in the turning back direction, includes the steering angle θ at that time. Therefore, if the driver performs a corrective steering while the steering wheel 3 is being turned back, the driver can intuitively recognize that the corrective steering has been performed.

[0091] Therefore, the driver can be motivated to perform appropriate steering.

[0092] In the second embodiment, too, by assigning the notes of the musical scale "Do," "Re," "Mi," "Fa," "So," "La," "Si," and "Do" in order to the range from the reference steering angle θ0 to the assumed maximum steering angle θz, the driver can easily recognize the maximum steering angle when passing through a cornering section.

[0093] 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.

[0094] For example, in the above-described embodiments, when it is determined that there is a turning section ahead in the traveling direction of the vehicle 1 while the vehicle 1 is traveling, the steering angle range is divided into a plurality of angle regions based on the assumed steering angle, and sounds are assigned to the divided angle regions. However, the technology of the present disclosure is not limited to this example. If the vehicle 1 is equipped with a navigation system, when the destination and traveling route of the vehicle 1 are set, a turning section present on the traveling route may be identified and sounds assigned based on the map data and road shape data recorded in the map data storage unit 57. Even when sounds are assigned in this manner, the same effects as those of the above-described embodiments can be obtained.

[0095] In addition, in each of the above embodiments, musical scales are assigned to multiple angular regions so that the musical scale changes stepwise with changes in the steering angle θ, but the technology of the present disclosure is not limited to this example. For example, in addition to assigning sounds so that the musical scale changes stepwise with changes in the steering angle θ, sounds may be assigned so that the pitch of the sounds changes in order of frequency. Furthermore, sounds may be assigned so that the rhythm or pitch of musical sounds changes stepwise, or sounds may be assigned so that the number of sounds constituting the output sound changes stepwise. Even when sounds are assigned in this manner, the driver can intuitively recognize changes in the steering state, and effects similar to those of each of the above embodiments can be obtained.

[0096] Furthermore, in each of the above embodiments, no sound is assigned to the range exceeding the assumed maximum steering angle θz. However, a sound may be assigned to the range exceeding the assumed maximum steering angle θz. For example, the second standard scale may also be assigned to the range exceeding the assumed maximum steering angle θz. As a result, the driver feels the scale gradually increase as the steering wheel 3 is turned further, but if the steering wheel 3 is turned too far beyond the assumed maximum steering angle θz, the driver can recognize that he / she has turned the steering wheel 3 too far because there is no change in the scale. Alternatively, the range exceeding the assumed maximum steering angle θz may also be divided into a plurality of angle ranges, and a scale exceeding the second standard scale may be assigned to follow the change from the first standard scale to the second standard scale. As a result, if the driver turns the steering wheel 3 too far, a sound of a scale exceeding the second standard scale is output, allowing the driver to recognize that he / she has turned the steering wheel 3 too far.

[0097] Furthermore, in each of the above embodiments, the vehicle information acquisition device 11 and the road shape information acquisition device 15 of the driving assistance system 10 are sensors provided in the vehicle 1, the output device 21 is a speaker system provided in the vehicle, and the information processing device 50 is communicatively connected to the vehicle information acquisition device 11, the road shape information acquisition device 15, and the output device 21 via a communication bus such as a CAN. However, the technology of the present disclosure is not limited to this example. For example, the functions of the information processing device 50 may be realized as functions of a mobile terminal device such as a smartphone. 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. Configuring the driving assistance system 10 using a mobile terminal device makes it possible to use auditory stimulation output processing regardless of the vehicle 1 being driven, thereby increasing opportunities for the driver to improve their driving skills.

[0098] It is also understood that the following aspects fall within the technical scope of the present disclosure. A driving assistance system in which a processing unit of an information processing device sets a standard rotation operation of the steering wheel corresponding to a predicted trajectory, and differentiates the intervals of angle regions assigned so that the musical scale changes gradually when the steering angle changes in the rotation direction of the standard rotation operation of the steering wheel from the intervals of angle regions assigned so that the musical scale changes gradually when the steering angle changes in the direction opposite to the rotation direction of the standard rotation operation of the steering wheel. A driving assistance system that assists a driver in steering operation, comprising: a predicted trajectory calculation unit that calculates a predicted trajectory of the vehicle; an assumed steering angle calculation unit that calculates an assumed steering angle of the steering wheel corresponding to the predicted trajectory; a sound setting unit that divides the range of the steering angle of the steering wheel into a plurality of angle ranges based on the assumed steering angle and assigns a sound to each angle range; and an output control unit that outputs the assigned sound in accordance with the detected steering angle. A driving assistance device (information processing device) that assists a driver in steering operations, comprising one or more processors and one or more memories communicably connected to the one or more processors, wherein the processor acquires information on a predicted trajectory of the vehicle, calculates an assumed steering angle of the steering wheel corresponding to the predicted trajectory, divides the range of the steering angle of the steering wheel into a plurality of angle regions based on the assumed steering angle, assigns a sound to each angle region, and outputs the assigned sound in accordance with the detected steering angle. a vehicle equipped with at least a vehicle information acquisition device that detects the steering angle of a steering wheel; a road shape information acquisition device that acquires information on the road shape ahead in the vehicle's direction of travel; a predicted trajectory calculation unit that acquires information on a predicted trajectory of the vehicle; an assumed steering angle calculation unit that calculates an assumed steering angle of the steering wheel corresponding to the predicted trajectory; a sound setting unit that divides the range of the steering angle of the steering wheel into a plurality of angle ranges based on the assumed steering angle and assigns a sound to each angle range; and an output control unit that outputs the assigned sound in accordance with the detected steering angle. A recording medium on which the computer program disclosed in the above embodiment is recorded. [Explanation of symbols]

[0099] 1: vehicle, 3: steering wheel, 10: driving assistance system, 11: vehicle information acquisition device, 12: steering angle sensor, 13: vehicle speed sensor, 14: selector switch, 15: road shape information acquisition device, 16: front-view camera, 17: vehicle position detection sensor, 21: output device, 50: information processing device, 51: communication unit, 53: processing unit, 55: memory unit, 57: map data memory unit, 61: acquisition unit, 63: predicted trajectory calculation unit, 65: assumed steering angle calculation unit, 67: sound setting unit, 69: output control unit, θ0: reference steering angle, θz: assumed maximum steering angle

Claims

1. In a driving assistance system that assists the driver in steering, one or more processors; and one or more memories communicatively coupled to the one or more processors; The processor: Obtain information on the vehicle's predicted trajectory, determining an assumed steering angle of the steering wheel corresponding to the predicted trajectory; dividing a steering angle range of the steering wheel into a plurality of angle regions based on the assumed steering angle, and allocating a sound to each of the angle regions; A driving assistance system that outputs a sound assigned to the driver depending on the detected steering angle.

2. The processor: The driving assistance system according to claim 1 , wherein the sound is assigned so that the tone scale changes stepwise as the steering wheel is rotated in one direction during operation of the steering wheel.

3. The processor: calculating an expected maximum steering angle according to a radius of curvature of a turning section of the predicted trajectory; The driving assistance system according to claim 2 , wherein sounds from a first standard scale to a second standard scale that are set in advance are allocated in stages within a range from a standard steering angle to the assumed maximum steering angle.

4. The processor:

4. The driving assistance system according to claim 3, wherein the angle of each angle region obtained by dividing a range from a reference steering angle to a predetermined angle is set smaller than the angle of each angle region obtained by dividing a range from the predetermined angle to the assumed maximum steering angle.

5. A computer program applied to a driving assistance system that assists a driver in steering operation, one or more processors, Obtaining information about a predicted trajectory of a vehicle; determining an estimated steering angle of the steering wheel corresponding to the predicted trajectory; Dividing a steering angle range of the steering wheel into a plurality of angle regions based on the assumed steering angle, and allocating a sound to each angle region; outputting the assigned sound in accordance with the detected steering angle; A computer program that causes a process including the steps of:

Images