Driving assistance device

Abstract

The present invention provides a driving assistance device (100), comprising: an information acquisition unit (21) that acquires traffic signal information and position information indicating the position of the own vehicle (101) relative to a traffic signal (201); a derivation unit (22) that derives a recommended driving for the driver based on the acquired traffic signal information and position information; a display unit (10) that displays information; a display control unit (24) that controls the display unit (10) to notify the driver of the information on the derived recommended driving; and a detection unit (4) that detects the degree of approach of the own vehicle (101) to a preceding vehicle. The display control unit (24) controls the display unit (10) such that the information on the maximum value (V1) of the recommended vehicle speed derived by the derivation unit (22) is changed and displayed according to the degree of approach detected by the detection unit (4).

Description

Technical Field

[0001] The present invention relates to a driving assistance device for assisting a driver's driving operation. Background Art

[0002] As such a device, a device that notifies a driver of a vehicle traveling on a road provided with a traffic signal of the start timing of a deceleration operation has been conventionally known. Such a device is described, for example, in Patent Document 1. In the device described in Patent Document 1, in order to pass through an intersection provided with a traffic signal without stopping, the display unit notifies the driver of the timing of the deceleration operation.

[0003] When there is a preceding vehicle traveling in front of the own vehicle, by giving a prompt corresponding to this situation to the driver, it is possible to improve traffic safety without disturbing the surrounding traffic flow and suppress a decrease in traffic flow. However, in the device described in Patent Document 1 above, no suggestions are made regarding the prompt to the driver when there is a preceding vehicle.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2014-096016 (JP2014-096016A). Summary of the Invention

[0007] A driving assistance device according to one aspect of the present invention includes: an information acquisition unit that acquires traffic signal information including switching information of a traffic signal for notifying a driver to stop or not stop at a specified position and position information indicating the position of the own vehicle relative to the traffic signal; a derivation unit that derives a recommended driving for the driver based on the traffic signal information and the position information acquired by the information acquisition unit; a display unit that displays information; a display control unit that controls the display unit to notify the driver of information on a recommended vehicle speed included in the recommended driving derived by the derivation unit; and a detection unit that detects the degree of approach of the own vehicle to a preceding vehicle traveling in front of the own vehicle. The display control unit controls the display unit so that information on the maximum value of the recommended vehicle speed derived by the derivation unit is changed and displayed according to the degree of approach of the own vehicle to the preceding vehicle detected by the detection unit. Brief Description of the Drawings

[0008] The object, features, and advantages of the present invention will be further clarified by the following description of embodiments related to the drawings.

[0009] Figure 1A FIG. is an example of a driving scene of a vehicle equipped with a driving assistance device according to an embodiment of the present invention.

[0010] Figure 1B This is a diagram showing another example of a driving scene of a vehicle equipped with a driving assistance device according to an embodiment of the present invention.

[0011] Figure 2A This is a diagram showing an example of a display image of a driving assistance device according to an embodiment of the present invention.

[0012] Figure 2B This is a diagram showing another example of a display image of a driving assistance device according to an embodiment of the present invention.

[0013] Figure 3 This is a block diagram showing the main components of a driving assistance device according to an embodiment of the present invention.

[0014] Figure 4 This is a diagram showing an example of a display image in the presence of a preceding vehicle.

[0015] Figure 5 This shows the processing Figure 3 executed by the controller of... Detailed Embodiments

[0016] The following is a description of an embodiment of the present invention with reference to Figures 1A to 5 ... Figure 1A and Figure 1B This is a diagram showing an example of a driving scene of the host vehicle equipped with a driving assistance device according to an embodiment of the present invention. In Figure 1A and Figure 1B examples are shown in which the host vehicle 101 travels along the arrow A on a road provided with a traffic signal (abbreviated as a signal) 201. In particular, Figure 1A shows an example in which there is no preceding vehicle traveling in front of the host vehicle 101 in the section from the host vehicle 101 to the signal 201, Figure 1B shows an example in which there is a preceding vehicle 102.

[0017] The signal 201 is configured to sequentially switch to red indicating a stop command, green indicating that travel is possible, and yellow indicating that travel is possible when it is difficult to stop safely at a predetermined cycle. It should be noted that the signal may also be an arrow signal that shows the direction in which travel is possible instead of switching the light color. It may also be a device that sequentially switches to green and red.

[0018] The host vehicle 101 receives the signal information of the signal 201 from a communication device such as an optical beacon or a radio beacon provided on the side of the road (for example, an optical beacon roadside unit 202). The signal information includes the switching information of the signal 201, that is, switching information such as the remaining time until the signal 201 switches from green to yellow and the remaining time until it switches from red to green. Figure 1A andFigure 1B An example is shown in which the vehicle 101 passes through the intersection where the traffic signal 201 is installed without stopping, that is, an example in which the vehicle 101 passes through without stopping at the stop line 203.

[0019] In this way, in a situation where the vehicle 101 travels toward the intersection where the traffic signal 201 is installed, the driving assistance device according to the embodiment of the present invention is configured to provide predetermined information to the driver of the vehicle 101 based on the traffic signal information received from the optical beacon roadside unit 202. That is, the driving assistance device has a driving assistance function of notifying the driver of information on the vehicle speed range (information on the target vehicle speed range) in which the vehicle 101 can pass through the intersection without stopping, information on the deceleration instruction when the vehicle 101 stops at the intersection, and the like.

[0020] The information on the vehicle speed range and the information on the deceleration instruction are displayed on a display device provided on the instrument panel facing the driver. It is also possible to use the display of the navigation unit disposed near the instrument panel as the display device. The display device may also be constituted by a head-up display that projects an image on the front windshield or a panel provided near the front windshield.

[0021] Figure 2A FIG. is an example of a display screen 10a displayed on a display device (monitor) when the vehicle approaches the traffic signal. As Figure 2A shown, an image showing the target vehicle speed range is displayed in an area A1 on one side (for example, the right side) of the left and right on the display screen 10a, and an image showing whether the vehicle can pass through the intersection where the traffic signal is installed without stopping is displayed in an area A2 on the other side (for example, the left side) of the left and right. Figure 2A This corresponds to the display screen 10a of the vehicle traveling toward the traffic signal 201 as shown in FIG. 1, for example.

[0022] The image in the area A1 includes a scale image 11 that shows the vehicle speed and numerical values together with scales, a target vehicle speed image 12 (shaded) showing the target vehicle speed range in which the vehicle can pass through the intersection where the traffic signal is installed in front of the vehicle without stopping, a bar-shaped own vehicle speed image 13 showing the current vehicle speed of the vehicle, and a bar-shaped legal speed image 14 showing the legal speed of the road. The target vehicle speed image 12, the own vehicle speed image 13, and the legal speed image 14 are in correspondence with the scale image 11, that is, they are displayed on the scale image 11. The monitor has a color display, and the scale image 11, the target vehicle speed image 12, the own vehicle speed image 13, and the legal speed image 14 are displayed in mutually different colors. The target vehicle speed image 12 is shown as a band-shaped image extending from the minimum value V0 to the maximum value V1 of the target vehicle speed. In Figure 2A this case, the maximum value of the target vehicle speed range coincides with the legal speed. It should be noted that the display of the legal speed image 14 may also be omitted.

[0023] In area A2, a background image 15 schematically showing a road and a traffic signal and a driving action image 16 (shaded) showing that the present vehicle can travel through an intersection with a traffic signal without stopping are displayed. The driving action image 16 is an image showing the driving action of the present vehicle 101 passing through an intersection with a traffic signal 201 without stopping. As long as the vehicle speed of the present vehicle is within the target vehicle speed range, the present vehicle can travel through the intersection without stopping. In Figure 2A the example, on the image of the road in the background image 15, an arrow image exceeding the traffic signal image is used to represent the driving action image 16. In this way, a vehicle speed image 13 of the present vehicle showing the current vehicle speed is displayed in correspondence with a target vehicle speed image 12 showing the target vehicle speed range, and the driving action image 16 of the present vehicle is also displayed. Thus, the driver can easily grasp whether it is necessary to accelerate or decelerate the present vehicle in order to smoothly pass through an intersection with a traffic signal, and good driving assistance can be provided to the driver.

[0024] When the traffic signal changes from green to red before the present vehicle reaches the traffic signal, or when the traffic signal is still red at the time when the present vehicle reaches the traffic signal, the present vehicle needs to stop in front of the traffic signal. Figure 2B FIG. is an example of a display screen 10a in this case. Figure 2B Corresponds to, for example, the display screen 10a when the present vehicle stops at a stop line 203 in front of a traffic signal 201 such as Figure 1A .

[0025] As Figure 2B shown, a target vehicle speed image 12, a vehicle speed image 13 of the present vehicle, and a legal speed image 14 are displayed in area A1. The target vehicle speed image 12 is an image showing a target vehicle speed range for smoothly stopping the present vehicle in motion at a stop line while suppressing the deceleration below a specified value. It should be noted that the display of the target vehicle speed image 12 can also be omitted. In area A2, a deceleration instruction image 17 showing a deceleration instruction for the present vehicle is displayed on the background image 15. Specifically, a deceleration instruction image 17 including an image 17a of a stop line and a strip-shaped image 17b shaded as shown is displayed. In this way, when it is necessary to decelerate the present vehicle in order to stop the present vehicle in front of the traffic signal, by displaying the deceleration instruction image 17 showing an instruction for a deceleration operation, the driver can easily recognize the necessity of the deceleration operation and can perform a deceleration operation on the present vehicle at a good timing.

[0026] However, as Figure 1BAs shown, when the driver drives according to the display on the display screen 10a in the state where there is a preceding vehicle 102, the host vehicle 101 may approach (e.g., rapidly approach) the preceding vehicle 102. Specifically, when the maximum value of the target vehicle speed specified by the target vehicle speed image 12 is faster than the vehicle speed of the preceding vehicle 102, when the driver who refers to the target vehicle speed range information drives at the maximum value of the target vehicle speed in order to pass through the intersection without stopping, the host vehicle 101 approaches the preceding vehicle 102. In order to improve safety in this case, the driving assistance device of the present embodiment is configured as follows.

[0027] Figure 3 is a block diagram schematically showing the main part configuration of the driving assistance device 100 according to an embodiment of the present invention. As Figure 3 shown, the driving assistance device 100 includes a controller 20 and a communication unit 1, a positioning sensor 2, a vehicle speed sensor 3, a distance sensor 4, and a monitor 10 that are respectively communicably connected to the controller 20.

[0028] The communication unit 1 is configured to be able to perform wireless communication with a roadside optical beacon 202 ([[]]END]] Figure 1A , Figure 1B ) provided on the road, that is, to be able to perform vehicle-to-vehicle communication. The communication unit 1 receives traffic signal information about the traffic signal located in the traveling direction of the host vehicle, that is, the traffic signal at the intersection that the host vehicle is about to pass through, from the communication device provided in the roadside optical beacon 202. The traffic signal information includes the position information of the traffic signal and the information on the switching time of the traffic signal light color. The information on the switching time includes the remaining time until the traffic signal switches from green to yellow when the traffic signal is currently green, and the remaining time until the traffic signal switches to green next when the traffic signal is currently a color other than green (e.g., red).

[0029] The positioning sensor 2 receives positioning signals transmitted from positioning satellites. The positioning satellites are artificial satellites such as GPS satellites and quasi-zenith satellites. The current position (latitude, longitude, altitude) of the host vehicle is measured using the positioning information received by the positioning sensor 2. The positioning sensor 2 is used to detect the position of the host vehicle relative to the intersection where the traffic signal is provided (distance to the traffic signal, etc.). Therefore, a distance detector (radar, lidar, etc.) that detects the distance from the host vehicle to an object (an object near the intersection) can also be used instead of the positioning sensor 2. The vehicle speed sensor 3 detects the vehicle speed of the host vehicle.

[0030] The distance sensor 4 detects as Figure 1BThe inter-vehicle distance L from the present vehicle 101 to the preceding vehicle 102 is shown. A lidar, a radar, etc. can be used as the distance sensor 4. The lidar measures the distance and direction to the object (preceding vehicle) by irradiating pulsed infrared laser light and detecting the reflected light reflected by the object, and the radar detects the distance and direction to the object by irradiating electromagnetic waves and detecting the reflected waves. It should be noted that the lidar and the radar can also detect the speed of the object.

[0031] The controller 20 performs prescribed processing based on signals from the communication unit 1, the positioning sensor 2, the vehicle speed sensor 3, and the distance sensor 4, and outputs a control signal to the monitor 10 having the display screen 10a. The controller 20 is configured by a computer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and other peripheral circuits such as an I / O (Input / Output) interface. The controller 20 has a functional structure including an information acquisition unit 21, a driving guidance unit 22, a vehicle speed detection unit 23, and a display control unit 24. Road information is prestored in the memory of the controller 20. The road information includes information on the legal speed of each road.

[0032] The information acquisition unit 21 acquires the traffic signal information received by the communication unit 1, the information on the current position of the present vehicle (position information) detected by the positioning sensor 2, the information on the vehicle speed of the present vehicle (vehicle speed information) detected by the vehicle speed sensor 3, and the information on the inter-vehicle distance from the preceding vehicle (inter-vehicle distance information) detected by the distance sensor 4. It should be noted that the inter-vehicle distance information also includes the speed of the preceding vehicle. Further, the information acquisition unit 21 determines the road on which the vehicle is traveling based on the position information of the present vehicle, and acquires the information on the legal speed (legal speed information) corresponding to the road based on the road information prestored in the memory.

[0033] The driving guidance unit 22 derives recommended driving recommended to the driver based on the traffic signal information, the position information, the vehicle speed information, and the legal speed information acquired by the information acquisition unit 21. Specifically, the distance from the present vehicle to the intersection where the traffic signal is provided is calculated using the position information, and the range of vehicle speeds at which the present vehicle can pass through the intersection without stopping is calculated based on the distance and the remaining time until the traffic signal ahead of the present vehicle changes from green to yellow included in the traffic signal information. Then, the range of vehicle speeds below the legal vehicle speed within the range of the vehicle speeds is calculated as the target vehicle speed range. The target vehicle speed range is included in the recommended driving recommended to the driver.

[0034] On the other hand, when it is determined that the host vehicle cannot pass through the intersection without stopping at a speed below the legal speed, the driving guidance unit 22 calculates the range of the target speed for smoothly stopping the host vehicle in front of the traffic signal. Then, when the speed of the host vehicle included in the vehicle speed information exceeds the target speed, a deceleration command including the target speed range is derived as recommended driving. Alternatively, instead of calculating the range of the target speed, only a deceleration command for stopping in front of the traffic signal is derived.

[0035] The vehicle speed detection unit 23 detects the speed of the preceding vehicle based on the speed of the host vehicle detected by the vehicle speed sensor 3 and the change amount of the inter-vehicle distance L detected by the distance sensor 4. That is, since the change amount of the inter-vehicle distance L per unit time corresponds to the relative speed of the preceding vehicle with respect to the host vehicle, the speed of the preceding vehicle is detected (calculated) by adding the speed of the host vehicle and the relative speed. It should be noted that the speed information of the preceding vehicle can also be obtained from the preceding vehicle via the communication unit 1, thereby detecting the speed of the preceding vehicle.

[0036] The display control unit 24 controls the display of the monitor 10 so as to display the recommended driving derived by the driving guidance unit 22. For example, in a state where there is no preceding vehicle as shown in Figure 1A , when the driving guidance unit 22 determines that the host vehicle can pass through the intersection without stopping, the monitor 10 is controlled to display, as shown in Figure 2A , in addition to the target speed image 12, the host vehicle speed image 13, the legal speed image 14 and the scale image 11 being displayed in correspondence, a driving action image 16 showing that the intersection can be passed through without stopping is also displayed on the background image 15.

[0037] On the other hand, when the driving guidance unit 22 determines that the host vehicle cannot pass through the intersection without stopping, the display control unit 24 controls the monitor 10 to display, as shown in Figure 2B , in addition to the target speed image 12, the host vehicle speed image 13, the legal speed image 14 and the scale image 11 being displayed in correspondence, a deceleration command image 17 showing a deceleration operation command is also displayed on the background image 15. It should be noted that Figure 2A , Figure 2B is a display image in a case where it is impossible to approach the preceding vehicle or it is impossible to approach the preceding vehicle by a specified degree or more in the section up to the traffic signal 201.

[0038] The display control unit 24 is as shown in Figure 1BIn the state where a preceding vehicle is present as shown, the monitor 10 is controlled as follows. The display control unit 24 first determines whether the speed of the preceding vehicle detected by the vehicle speed detection unit 23 is less than the maximum value V1 of the target speed range derived by the driving derivation unit 22. When it is determined that the speed of the preceding vehicle is equal to or higher than the maximum value V1 of the target speed range, the host vehicle is not approaching the preceding vehicle. In this case, Figure 2A the same as that, the monitor 10 is controlled to display an image showing recommended driving.

[0039] On the other hand, when it is determined that the speed of the preceding vehicle is less than the maximum value V1 of the target speed range, the host vehicle may approach the preceding vehicle. In this case, the display control unit 24 also determines whether the inter-vehicle distance L is equal to or less than a specified value La based on the inter-vehicle distance information acquired by the information acquisition unit 21. The specified value La is set according to the vehicle speed, and the faster the vehicle speed, the larger the specified value La. When the inter-vehicle distance L is greater than the specified value La, the monitor 10 is controlled to display an image Figure 2A the same as that. When the inter-vehicle distance L is equal to or less than the specified value La, the monitor 10 is controlled in such a way as to reduce the maximum value V1 of the target speed shown by the target speed image 12.

[0040] Figure 4 is a diagram showing this example, which is an example of the display when the host vehicle can pass through the intersection under a green signal. As Figure 4 shown, a different target speed image 12 is displayed in the display image 10a. That is, the maximum value V2 of the target speed shown by the target speed image is smaller than Figure 2A the maximum value V1 of that, and the overall length of the target speed image 12 is shorter compared to Figure 2A that. It should be noted that in Figure 2A the display of the legal speed image 14 is omitted, but the legal speed image 14 may also be displayed. Figure 4 The maximum value V2 of the target speed in

[0041] Figure 4 is set to the same value as, for example, the speed of the preceding vehicle. Thereby, it is possible to prevent the host vehicle from approaching the preceding vehicle. The maximum value V2 may also be set according to the inter-vehicle distance L between the host vehicle and the preceding vehicle. For example, the shorter the inter-vehicle distance L, the smaller the maximum value V2 may be set. Also, the faster the speed of the host vehicle is compared to the speed of the preceding vehicle, the smaller the maximum value V2 may be set. Since the maximum value V2 of the target speed when there is a preceding vehicle is smaller than the maximum value V1 when there is no preceding vehicle, the driver drives such that the vehicle speed is within the target speed range, whereby the host vehicle can pass through the intersection smoothly without approaching the preceding vehicle too closely. Therefore, useful information can be provided to the driver in the presence of a preceding vehicle.

[0042] Figure 5 is shown byFigure 3 Flowchart of an example of the process executed by the controller 20. The process shown in this flowchart starts, for example, when the power button switch is turned on and is repeated at a specified cycle.

[0043] As Figure 5 shown, first, in S1 (S: processing step), the signal information of the traffic signal received by the communication unit 1 is acquired, and the position information of the own vehicle obtained from the signal of the positioning sensor 2, the vehicle speed information obtained from the signal of the vehicle speed sensor 3, and the inter-vehicle distance information obtained from the signal of the distance sensor 4 are acquired. The traffic signal information includes information on the remaining time (green signal remaining time, red signal remaining time) until the traffic signal changes from green to yellow or from red to green. Also in S1, the information on the legal speed of the road being traveled is acquired with reference to the road information prestored in the memory. Note that the information on the legal speed of the road being traveled can also be acquired by recognizing road signs with an in-vehicle camera.

[0044] Next, in S2, based on the traffic signal information, position information, and legal speed information acquired in S1, a target vehicle speed range with the legal speed as the upper limit is calculated as a recommended driving for the driver. That is, a target vehicle speed range that can pass through the intersection where the traffic signal is installed without stopping or a target vehicle speed range in the case of stopping in front of the traffic signal is calculated. In other words, the minimum value V0 and the maximum value V1 of the target vehicle speed are calculated.

[0045] Next, in S3, it is determined based on the signal from the distance sensor 4 whether there is a preceding vehicle within a specified distance. It is also possible to determine whether there is a preceding vehicle based on an image from a camera mounted on the own vehicle that captures the surroundings of the own vehicle. The specified distance is, for example, the distance from the current location to the traffic signal. When S3 is negative (S3: no), the process proceeds to S4.

[0046] In S4, a control signal is output to the monitor 10 to display an image of recommended driving including the target vehicle speed range calculated in S2. Outputting a control signal to the monitor 10 is, for example, as Figure 2A 、 Figure 2B shown, the target vehicle speed image 12 including the minimum value V0 and the maximum value V1, the own vehicle speed image 13, and the legal speed image 14 are displayed in correspondence with the scale image 11 of the area A1, and the driving action image 16 or the deceleration instruction image 17 is displayed on the background image 15.

[0047] On the other hand, when S3 is positive (S3: yes), the process proceeds to S5, and the vehicle speed Vf of the preceding vehicle is detected based on the vehicle speed information and the inter-vehicle distance information acquired in S1.

[0048] Next, in S6, it is determined whether the speed difference obtained by subtracting the maximum value V1 of the target speed range calculated in S2 from the vehicle speed Vf detected in S5 is equal to or greater than a specified value Va. This determination is to determine whether the host vehicle traveling according to the recommended driving is likely to approach the preceding vehicle. The specified value Va is set to 0, for example. When S6 is affirmative (S6: Yes), the process proceeds to S7, and when it is negative (S6: No), the process proceeds to S4.

[0049] In S7, a specified value La corresponding to the vehicle speed is set using the vehicle speed information obtained in S1, and it is determined whether the inter-vehicle distance L is equal to or less than the specified value La using the inter-vehicle distance information. When S7 is affirmative (S7: Yes), the process proceeds to S8, and when it is negative (S7: No), the process proceeds to S4.

[0050] In S8, a display maximum value V2 different from the maximum value V1 of the target vehicle speed included in the recommended driving calculated in S2 is calculated based on the inter-vehicle distance information obtained in S1. That is, a new maximum value V2 smaller than V1 is calculated. For example, the vehicle speed Vf of the preceding vehicle detected in S5 is calculated as the maximum value V2. The maximum value V2 of the target vehicle speed can also be calculated based on the inter-vehicle distance L or based on the speed difference between the host vehicle and the preceding vehicle so that the host vehicle does not approach the preceding vehicle too closely.

[0051] Next, in S9, a control signal is output to the monitor 10 so that an image of the recommended driving including the maximum value V2 of the target vehicle speed calculated in S8 is displayed. The monitor 10 is controlled to display, for example Figure 4 the image shown.

[0052] The operation of the driving support device 100 according to the present embodiment is summarized as follows. As Figure 1A shown, when the host vehicle 101 is approaching the intersection where the traffic signal 201 is provided and there is no preceding vehicle in front of the host vehicle 101, an image of the recommended driving as shown in, for example Figure 2A is displayed on the monitor 10. Specifically, the target vehicle speed image 12 showing the range from the minimum value V0 to the maximum value V1 of the target vehicle speed, which is used for the host vehicle 101 to pass through the intersection where the traffic signal 201 is provided without stopping, and the driving action image 16 that can pass through the intersection without stopping are displayed together (S4). As a result, the driver can easily recognize the target vehicle speed for passing through the intersection without stopping, and the host vehicle 101 can perform a smooth driving action.

[0053] On the other hand, as Figure 1BAs shown, when there is a preceding vehicle 102 in front of the host vehicle 101 at a distance L of 101, an image is displayed on the monitor 10 based on the difference between the maximum value V1 of the target speed shown in the target speed image 12 and the speed Vf of the preceding vehicle 102, and the inter-vehicle distance L between the host vehicle 101 and the preceding vehicle 102. That is, when the speed difference obtained by subtracting the maximum value V1 of the target speed from the speed Vf of the preceding vehicle 102 is equal to or greater than a specified value Va (for example, when the speed Vf is equal to or greater than the maximum value V1), an image showing recommended driving, which is the same as when there is no preceding vehicle 102, is displayed (S6 → S4). Even if the speed difference is lower than the specified value Va, as long as the inter-vehicle distance L is greater than the specified value La, it is impossible for the host vehicle 101 to quickly approach the preceding vehicle 102, and in this case, an image showing recommended driving, which is the same as when there is no preceding vehicle 102, is also displayed (S7 → S4).

[0054] In contrast, when the speed difference obtained by subtracting the maximum value V1 of the target speed from the speed Vf of the preceding vehicle 102 is smaller than the specified value Va and the inter-vehicle distance L is equal to or less than the specified value La, an image of recommended driving including the target speed image 12, as shown, for example, is displayed on the monitor 10 (S9). In this case, the maximum value V2 of the target speed is restricted and displayed (V2 < V1). Thus, even when there is a preceding vehicle 102, as long as the driver drives the host vehicle at a speed within the target speed range, the host vehicle 101 can pass through the intersection without getting too close to the preceding vehicle 102 and without stopping. Therefore, the driving safety when performing the passing assistance display at the intersection is improved. Figure 4 shown Figure 2A the maximum value V1 of which is restricted and displayed (V2 < V1). Thus, even when there is a preceding vehicle 102, as long as the driver drives the host vehicle at a speed within the target speed range, the host vehicle 101 can pass through the intersection without getting too close to the preceding vehicle 102 and without stopping. Therefore, the driving safety when performing the passing assistance display at the intersection is improved.

[0055] The present embodiment can achieve the following effects.

[0056] (1) The driving assistance device 100 of the present embodiment includes: an information acquisition unit 21 that acquires signal information including the switching information of a traffic signal and position information indicating the position of the host vehicle 101 relative to the traffic signal; a driving derivation unit 22 that derives recommended driving recommended to the driver based on the signal information and the position information acquired by the information acquisition unit 21; a monitor 10 that displays information; a display control unit 24 that controls the monitor 10 to notify the driver of the information on the recommended driving derived by the driving derivation unit 22; and a detection unit that detects the degree of approach of the host vehicle 101 to a preceding vehicle 102 traveling in front of the host vehicle, such as a distance sensor 4 that detects the inter-vehicle distance L from the host vehicle 101 to the preceding vehicle 102 ( Figure 3)。The display control unit 24 controls the monitor 10 so that the information on the maximum value V1 of the recommended vehicle speed derived by the driving derivation unit 22 changes according to the proximity (e.g., the inter-vehicle distance L) between the host vehicle 101 and the preceding vehicle 102 detected by the detection unit and is displayed. Figure 5 )。

[0057] More specifically, the display control unit 24 controls the monitor 10 so that when the proximity (e.g., the inter-vehicle distance L) between the host vehicle 101 and the preceding vehicle 102 detected by the distance sensor 4 or the like is equal to or greater than a specified value La, the recommended driving information including the information on the maximum value V1 of the recommended vehicle speed included in the recommended driving derived by the driving derivation unit 22 is displayed, and when the inter-vehicle distance L is lower than the specified value La, the recommended driving information including the information on the maximum value V2 smaller than the maximum value V1 is displayed. With this configuration, it is possible to notify the driver of the target vehicle speed range in which the host vehicle 101 can pass through the intersection without rapidly approaching the preceding vehicle 102 and without stopping. As a result, while improving safety, the host vehicle can smoothly pass through the intersection.

[0058] (2) The vehicle speed detection unit 23 uses the signals from the vehicle speed sensor 3 and the distance sensor 4 to detect the vehicle speed Vf of the preceding vehicle 102 that affects the proximity. The display control unit 24 controls the monitor 10 so that when the speed difference obtained by subtracting the maximum value V1 from the vehicle speed Vf of the preceding vehicle 102 detected by the vehicle speed detection unit 23 is equal to or greater than a specified value Va, the recommended driving information including the information on the maximum value V1 is displayed. Figure 2A ) When the speed difference is lower than the specified value Va, the recommended driving information including the information on the maximum value V2 smaller than the maximum value V1 is displayed. Figure 4 ) By changing the display of the maximum value of the target vehicle speed according to the speed difference from the preceding vehicle 102 in this way, it is possible to notify the driver of the optimal target vehicle speed for suppressing the approach of the host vehicle 101 to the preceding vehicle 102.

[0059] (3) The display control unit 24 controls the monitor 10 to display the target vehicle speed range by the strip-shaped target vehicle speed image 12 having a length corresponding to the range from the minimum value V0 to the maximum values V1 and V2 of the target vehicle speed. Figure 2A 、 Figure 4 ) Thus, the driver can easily recognize the target vehicle speed range based on the length of the image.

[0060] The above-described embodiments can be deformed in various ways. Several modification examples will be described below. In the above-described embodiment, the information acquisition unit 21 acquires the traffic signal information including the switching information of the traffic signal transmitted from the optical beacon roadside device 202. However, the current position of the own vehicle may also be determined by the positioning sensor 2, and the information acquisition unit may acquire the traffic signal information transmitted from the server device that manages the switching of the traffic signal corresponding to the current position. In the above-described embodiment, the position of the own vehicle is detected by the positioning sensor 2. However, a radar, a lidar, or a camera may also be used to detect the position of the own vehicle relative to the traffic signal.

[0061] In the above-described embodiment, the driving guidance unit 22 derives the recommended driving recommended to the driver based on the traffic signal information acquired by the information acquisition unit 21 and the position information of the own vehicle. Specifically, the speed range (target speed range) that the own vehicle should satisfy and the instruction to perform a deceleration operation (deceleration instruction) are derived as part of the recommended driving. However, the configuration of the derivation unit is not limited to the above. In the above-described embodiment, the information of the recommended driving derived by the driving guidance unit 22 is notified to the driver through the monitor 10 (display unit). However, it may also be notified to the driver by voice output in addition to the display.

[0062] In the above-described embodiment, the condition is that the speed difference obtained by subtracting the maximum value V1 of the target speed from the speed Vf of the preceding vehicle is lower than the specified value Va and the inter-vehicle distance L is equal to or less than the specified value La, and the maximum value of the target speed is changed from V1 (first maximum value) to V2 (second maximum value). However, it may also be the condition that the speed difference obtained by subtracting V1 from the speed Vf is lower than the specified value Va or the inter-vehicle distance L is equal to or less than the specified value La, and the maximum value of the target speed is changed from V1 to V2. Alternatively, the maximum value of the target speed may be changed from V1 to V2 according to other parameters indicating the degree of approach. That is, as long as the control monitor 10 is such that when the degree of approach between the own vehicle and the preceding vehicle is lower than the specified value, the recommended driving information including the information of the maximum value V1 of the recommended speed included in the recommended driving derived by the driving guidance unit 22 (derivation unit) is displayed, and when the degree of approach reaches the specified value or more, the recommended driving information including the information of the other maximum value V2 is displayed, the configuration of the display control unit may be in any form. The display control unit may also control the monitor 10 such that when the speed Vf of the preceding vehicle 102 is equal to or higher than the maximum value V1 of the target speed or the speed Vf is equal to or higher than the speed of the own vehicle detected by the vehicle speed sensor 3, the recommended driving information including the information of the maximum value V1 of the recommended speed is displayed, and when the speed Vf is lower than the maximum value V1 of the target speed or the speed Vf is lower than the speed of the own vehicle, the recommended driving information including the information of the other maximum value V2 is displayed.

[0063] In the above-described embodiment, the vehicle speed detection unit 23 uses the vehicle speed detected by the vehicle speed sensor 3 and the inter-vehicle distance L detected by the distance sensor 4 to detect the vehicle speed Vf of the preceding vehicle. As an example of the degree of approach, the vehicle speed difference between the preceding vehicle and the host vehicle is detected (calculated) using the vehicle speed Vf of the preceding vehicle detected by the vehicle speed detection unit 23. However, the configuration of the detection unit that detects the degree of approach between the host vehicle and the preceding vehicle is not limited to the above. It is also possible to perform time differentiation on the inter-vehicle distance L between the host vehicle and the preceding vehicle to obtain the change rate of the relative speed, thereby detecting the degree of approach.

[0064] In the above-described embodiment, the recommended vehicle speed range is displayed by the belt-shaped target vehicle speed image 12 having a length corresponding to the range from the minimum value V0 to the maximum values V1, V2 of the recommended vehicle speed (target vehicle speed). However, the configuration of the target vehicle speed image is not limited to the above. For example, the minimum and maximum values of the recommended vehicle speed can also be displayed numerically. It is also possible to display only the maximum value of the recommended vehicle speed. In order for the driver to recognize that the maximum value of the recommended vehicle speed is limited from V1 to V2 due to the presence of the preceding vehicle, the image showing the maximum value V1 and the image showing the maximum value V2 can also be displayed in different ways. For example, the two can be displayed in mutually different display colors. In the above-described embodiment, the display image 10a displays the target vehicle speed image 12, the host vehicle speed image 13, the legal speed image 14, etc. However, the display of the host vehicle speed image 13 and the legal speed image 14 can also be omitted.

[0065] In the above-described embodiment, the configuration of the driving assistance device 100 has been described by taking the case where the host vehicle passes through an intersection provided with a traffic signal as an example. However, the traffic signal is not limited to intersections and is sometimes provided at a crosswalk or the like. In this case, the driving assistance device of the present invention can also be applied in the same manner.

[0066] The present invention can also be used as a driving assistance method, including: a step of detecting the degree of approach between the host vehicle 101 and the preceding vehicle 102 traveling in front of the host vehicle 101; a step of obtaining signal light information including the switching information of the signal light 201 and position information indicating the position of the host vehicle 101 relative to the signal light 201; a step of deriving recommended driving recommended to the driver based on the signal light information and the position information; a step of controlling the display unit to notify the driver of the information of the recommended vehicle speed included in the recommended driving, and the control step includes controlling the display unit so that the information of the maximum value V1 of the recommended vehicle speed changes according to the detected degree of approach between the host vehicle 101 and the preceding vehicle 102 and is displayed.

[0067] One or more of the above-described embodiments and modifications can be arbitrarily combined, and the modifications can also be combined with each other.

[0068] The present invention enables safety - considered driving assistance in the presence of a preceding vehicle.

[0069] The present invention has been described above in conjunction with preferred embodiments, but those skilled in the art should understand that various modifications and changes can be made without departing from the scope of disclosure of the following claims.

Claims

1. A driving assistance device, characterized in that, Comprising: An information acquisition unit (21) that acquires signal information including switching information of a traffic signal (201) for notifying a driver of stopping or non-stopping at a specified position and position information indicating the position of the own vehicle (101) relative to the traffic signal (201); A derivation unit (22) that derives recommended driving recommended to the driver based on the signal information and the position information acquired by the information acquisition unit (21); A display unit (10) that displays information; A display control unit (24) that controls the display unit (10) to notify the driver of information on a recommended vehicle speed included in the recommended driving derived by the derivation unit (22); and A detection unit (4) that detects the degree of approach of the own vehicle (101) to a preceding vehicle traveling ahead of the own vehicle (101), The display control unit (24) controls the display unit (10) such that when the degree of approach of the own vehicle (101) to the preceding vehicle (102) detected by the detection unit (4) is lower than a specified value, recommended driving information including information on a first maximum value (V1), which is the maximum value of the recommended vehicle speed included in the recommended driving derived by the derivation unit (22), is displayed, and when the degree of approach reaches the specified value or more, recommended driving information including information on a second maximum value (V2) different from the first maximum value (V1) is displayed.

2. The driving assistance device according to claim 1, characterized in that The detection unit (4) detects a vehicle-to-vehicle distance (L) from the own vehicle (101) to the preceding vehicle (102), The display control unit (24) controls the display unit (10) such that when the vehicle-to-vehicle distance (L) detected by the detection unit (4) is a specified value (La) or more, recommended driving information including information on the first maximum value (V1) is displayed, and when the vehicle-to-vehicle distance (L) is lower than the specified value (La), recommended driving information including information on the second maximum value (V2) smaller than the first maximum value (V1) is displayed.

3. The driving assistance device according to claim 1, characterized in that It further comprises a vehicle speed detection unit (23) that detects the vehicle speed (Vf) of the preceding vehicle (102), The detection unit (4) detects a speed difference obtained by subtracting the first maximum value (V1) from the vehicle speed (Vf) of the preceding vehicle (102) detected by the vehicle speed detection unit (23), The display control unit (24) controls the display unit (10) such that when the speed difference is a specified value (Va) or more, recommended driving information including information on the first maximum value (V1) is displayed, and when the speed difference is lower than the specified value (Va), recommended driving information including information on the second maximum value (V2) smaller than the first maximum value (V1) is displayed.

4. The driving assistance device according to claim 1, characterized in that It also includes a vehicle speed detection unit (23) that detects the vehicle speed (Vf) of the preceding vehicle (102). The display control unit (24) controls the display unit (10) such that when the vehicle speed (Vf) of the preceding vehicle (102) detected by the vehicle speed detection unit (23) is equal to or higher than the first maximum value (V1), recommended driving information including information on the first maximum value (V1) is displayed, and when the vehicle speed (Vf) of the preceding vehicle (102) is lower than the first maximum value (V1), recommended driving information including information on the second maximum value (V2) smaller than the first maximum value (V1) is displayed.

5. The driving assistance device according to any one of claims 1 to 4, characterized in that: The display control unit (24) controls the display unit (10) such that a range of recommended vehicle speeds is displayed by a strip-shaped image having a length corresponding to the range from the minimum value (V0) to the maximum values (V1, V2) of the recommended vehicle speeds.

6. The driving assistance device according to any one of claims 1 to 4, characterized in that: The display control unit (24) controls the display unit (10) to display, in addition to information on the maximum value of the recommended vehicle speed, a driving action image (16) showing an action of the own vehicle (101) passing through the specified position without stopping.

7. A driving assistance method, characterized in that, Comprising: A step of detecting the proximity of the own vehicle (101) to a preceding vehicle (102) traveling in front of the own vehicle (101); A step of acquiring traffic signal information including switching information of a traffic signal (201) for notifying a driver of stopping or non-stopping at a specified position and position information indicating the position of the own vehicle (101) relative to the traffic signal (201); A step of deriving recommended driving recommended to the driver based on the traffic signal information and the position information; And A step of controlling the display unit (10) to notify the driver of information on the recommended vehicle speed included in the recommended driving, The step of control includes controlling the display unit (10) such that when the proximity of the own vehicle (101) to the preceding vehicle (102) detected by the detection unit (4) is lower than a specified value, recommended driving information including information on the first maximum value (V1), which is the maximum value of the recommended vehicle speed included in the recommended driving derived by the derivation unit (22), is displayed, and when the proximity reaches the specified value or higher, recommended driving information including information on the second maximum value (V2) different from the first maximum value (V1) is displayed.

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