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 the 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 of the derived recommended driving; and a distance measurement unit (4) that measures the inter-vehicle distance (L) from the own vehicle (101) to the preceding vehicle (102). The display control unit (24) controls the display unit (10) to display a first image corresponding to the information of the recommended driving when the inter-vehicle distance (L) measured by the distance measurement unit (4) is greater than a specified value (La), and to display the first image and a second image as a warning message together when the inter-vehicle distance (L) is less than or equal to the specified value (La).

Description

Technical Field

[0001] The present invention relates to a driving assistance device that assists 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 timing of the deceleration operation is notified to the driver through a display unit.

[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 affecting the surrounding traffic flow while suppressing a decrease in traffic flow. However, in the device described in Patent Document 1 above, no suggestion is 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 that notifies 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 the information of the recommended driving derived by the derivation unit; and a distance measurement unit that measures the inter-vehicle distance from the own vehicle to a preceding vehicle traveling in front of the own vehicle. The display control unit controls the display unit to display a first image corresponding to the information of the recommended driving when the inter-vehicle distance measured by the distance measurement unit is greater than a specified value, and to display a second image as a warning message together with the first image when the inter-vehicle distance is equal to or less than the specified value. 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 a diagram showing an example of a driving scene of a driving assistance device having an embodiment of the present invention.

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

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

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

[0015] Figure 4B This is a diagram showing Figure 4A a modified example of

[0016] Figure 4C This is a diagram showing Figure 4A another modified example of

[0017] Figure 5 This is a flowchart showing an example of a process executed by the controller of Figure 3 Detailed Embodiments

[0018] Hereinafter, embodiments of the present invention will be described with reference to Figures 1A to 5 Figure 1A , 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 , 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 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.

[0019] 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 does not switch the light color but shows the direction in which travel is possible with an arrow. It may also be a device that sequentially switches to green and red.

[0020] The vehicle 101 receives the signal information of the traffic signal 201 from communication devices such as optical beacons and radio beacons (such as the optical beacon roadside unit 202) provided on the side of the road. The signal information of the traffic signal includes the switching information of the traffic signal 201, that is, the remaining time until the traffic signal 201 switches from green to yellow and the remaining time until it switches from red to green, etc. Figure 1A , Figure 1B An example is shown in which the vehicle 101 passes through the intersection where the traffic signal 201 is provided without stopping, that is, an example in which the vehicle 101 passes through without stopping at the stop line 203.

[0021] In this way, in the situation where the vehicle 101 travels toward the intersection where the traffic signal 201 is provided, 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 command when the vehicle 101 stops at the intersection, and the like.

[0022] The information on the vehicle speed range and the information on the deceleration command are displayed on a display device provided on the instrument panel facing the driver. The display of the navigation unit disposed near the instrument panel can also be used as the display device. The display device can also be constituted by a head-up display that projects an image on the front windshield or a panel provided near the front windshield.

[0023] Figure 2A It is a diagram showing 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 the area A1 on one side (for example, the right side) of the left and right of the display screen 10a, and an image showing whether the vehicle can pass through the intersection where the traffic signal is provided without stopping is displayed in the area A2 on the other side (for example, the left side) of the left and right. Figure 2A It corresponds to the display screen 10a of the vehicle traveling toward the traffic signal 201 as shown in FIG. 1, for example.

[0024] The image of area A1 includes a scale image 11 that shows the vehicle speed and values together with scales, a target vehicle speed image 12 (shaded) that shows the target vehicle speed range within which the vehicle can pass through the intersection with a traffic signal in front of the vehicle without stopping, a bar-shaped own vehicle speed image 13 that shows the current vehicle speed of the vehicle, and a bar-shaped legal speed image 14 that shows 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. In Figure 2A , 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 can also be omitted.

[0025] In area A2, a background image 15 that schematically shows the road and the traffic signal and a driving action image 16 (shaded) that shows the driving action in which the vehicle can travel through the intersection with a traffic signal without stopping are displayed. The driving action image 16 is an image that shows the driving action of the vehicle 101 passing through the intersection with the traffic signal 201 without stopping. As long as the own vehicle speed is within the target vehicle speed range, the vehicle can pass through the intersection without stopping. In Figure 2A 's example, on the image of the road in the background image 15, the driving action image 16 is represented by an arrow image that exceeds the traffic signal image. In this way, the own vehicle speed image 13 that shows the current vehicle speed is displayed in correspondence with the target vehicle speed image 12 that shows the target vehicle speed range, and the driving action image 16 of the vehicle is also displayed. Thus, the driver can easily grasp whether it is necessary to accelerate or decelerate the vehicle in order to smoothly pass through the intersection with a traffic signal, and good driving assistance can be provided to the driver.

[0026] When the traffic signal changes from green to red before the vehicle reaches the traffic signal, or when the traffic signal is still red at the time when the vehicle reaches the traffic signal, the 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 vehicle stops at the stop line 203 in front of the traffic signal 201 in Figure 1A .

[0027] As Figure 2BAs shown, in area A1, a target vehicle speed image 12, a host vehicle speed image 13, and a legal speed image 14 are displayed. The target vehicle speed image 12 is an image showing a target vehicle speed range for smoothly stopping the host vehicle in motion at a stop line while suppressing 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 host 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 against the image 17a is displayed. In this way, when the host vehicle needs to decelerate to stop in front of a traffic signal, by displaying the deceleration instruction image 17 showing an instruction for the deceleration operation, the driver can easily recognize the necessity of the deceleration operation and can decelerate the host vehicle at an appropriate timing.

[0028] However, as Figure 1B shown, in a state where there is a preceding vehicle 102, when the driver drives according to the display on the display screen 10a, 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 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 such a situation, the driving assistance device of the present embodiment is configured as follows.

[0029] Figure 3 is a block diagram schematically showing the main part configuration of a 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.

[0030] The communication unit 1 is configured to be able to perform wireless communication with a beacon roadside unit 202 ( 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 a traffic signal located in the traveling direction of the host vehicle, that is, a traffic signal at an intersection that the host vehicle is about to pass through, from a communication device provided in the beacon roadside unit 202. The traffic signal information includes the position information of the traffic signal and information on the switching time of the traffic signal lamp color. The information on the switching time includes information on the remaining time until switching from green to yellow when the traffic signal is currently green and information on the remaining time until switching to green next when the traffic signal is currently a color other than green (e.g., red).

[0031] The positioning sensor 2 receives a positioning signal transmitted from a positioning satellite. The positioning satellite is an artificial satellite such as a GPS satellite or a quasi-zenith satellite. The current position (latitude, longitude, altitude) of the own vehicle is determined using the positioning information received by the positioning sensor 2. The positioning sensor 2 is used to detect the position of the own vehicle (distance to the signal light, etc.) relative to the intersection where the signal light is installed. Therefore, a distance detector (radar, lidar, etc.) that detects the distance from the own 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 own vehicle.

[0032] The distance sensor 4 detects the Figure 1B inter-vehicle distance L from the own vehicle 101 to the preceding vehicle 102 as shown. A lidar, radar, etc. can be used as the distance sensor 4. The lidar measures the distance and direction to the object by irradiating pulsed infrared laser light and detecting the reflected light reflected by the object (preceding vehicle), and the radar detects the distance and direction to the object by irradiating electromagnetic waves and detecting the reflected wave. It should be noted that the speed of the object can also be detected using a lidar or radar.

[0033] 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 a 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 derivation unit 22, a vehicle speed detection unit 23, and a display control unit 24. Road information is pre-stored in the memory of the controller 20. The road information includes information on the legal speed of each road.

[0034] The information acquisition unit 21 acquires the signal light information received by the communication unit 1, the information on the current position of the own vehicle (position information) detected by the positioning sensor 2, the information on the vehicle speed of the own vehicle (vehicle speed information) detected by the vehicle speed sensor 3, and the information on the inter-vehicle distance from the own vehicle to 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 own vehicle, and acquires the information on the legal speed (legal speed information) corresponding to the road based on the road information pre-stored in the memory.

[0035] The driving guidance unit 22 derives the recommended driving for the driver based on the traffic signal information, position information, vehicle speed information, and legal speed information obtained by the information acquisition unit 21. Specifically, it calculates the distance from the own vehicle to the intersection where the traffic signal is installed using the position information, and calculates the range of vehicle speeds at which the own vehicle can pass through the intersection without stopping based on this distance and the remaining time until the traffic signal ahead of the own vehicle changes from green to yellow included in the traffic signal information. Then, it calculates the range of vehicle speeds below the legal speed within this vehicle speed range as the target vehicle speed range. The target vehicle speed range is included in the recommended driving recommended to the driver.

[0036] On the other hand, when it is determined that the own vehicle cannot pass through the intersection without stopping at a speed below the legal speed, the driving guidance unit 22 calculates the range of target vehicle speeds for smoothly stopping the own vehicle in front of the traffic signal. Then, when the vehicle speed of the own vehicle included in the vehicle speed information exceeds the target vehicle speed, it derives a deceleration command including the target vehicle speed range as the recommended driving. Or instead of calculating the range of target vehicle speeds, it only derives a deceleration command for stopping in front of the traffic signal.

[0037] The vehicle speed detection unit 23 detects the vehicle speed of the preceding vehicle based on the vehicle speed of the own 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, the change amount of the inter-vehicle distance L per unit time corresponds to the relative vehicle speed of the preceding vehicle with respect to the own vehicle, and the vehicle speed of the own vehicle is added to the relative vehicle speed to detect (calculate) the vehicle speed of the preceding vehicle. It should be noted that the vehicle speed information of the preceding vehicle can also be obtained from the preceding vehicle via the communication unit 1, thereby detecting the vehicle speed of the preceding vehicle.

[0038] The display control unit 24 controls the display of the monitor 10 in a manner that displays 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 it is determined by the driving guidance unit 22 that the own vehicle can pass through the intersection without stopping, the monitor 10 is controlled so that, as shown in Figure 2A In addition to the target vehicle speed image 12, the own 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.

[0039] On the other hand, when it is determined by the driving guidance unit 22 that the own vehicle cannot pass through the intersection without stopping, the display control unit 24 controls the monitor 10 as shown in Figure 2BAs shown, in addition to the target vehicle speed image 12, the own vehicle speed image 13, the legal speed image 14 and the scale image 11 being displayed in a corresponding relationship, a deceleration instruction image 17 showing a deceleration operation instruction is also displayed on the background image 15. It should be noted that for convenience, Figure 2A , Figure 2B the images shown are called reference images. The reference image is a display image in a situation where it is impossible to approach the preceding vehicle or impossible to approach the preceding vehicle to a degree above the specified level in the section up to the signal machine 201. The reference image is an image for assisting in passing through the intersection.

[0040] The display control unit 24 controls the monitor 10 as follows in a state where there is a preceding vehicle as shown in Figure 1B . The display control unit 24 first determines whether the vehicle speed of the preceding vehicle detected by the vehicle speed detection unit 23 is smaller than the maximum value of the target vehicle speed range derived by the driving derivation unit 22. When it is determined that the vehicle speed of the preceding vehicle is above the maximum value of the target vehicle speed range, the own vehicle is not approaching the preceding vehicle. In this case, Figure 2A the same as, the monitor 10 is controlled to display the reference image.

[0041] On the other hand, when it is determined that the vehicle speed of the preceding vehicle is smaller than the maximum value of the target vehicle speed range, the own vehicle may approach the preceding vehicle. In this case, the display control unit 24 also determines whether the inter-vehicle distance L is less than or equal to a specified value La according to 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 the reference image. When the inter-vehicle distance L is less than or equal to the specified value La, in order to alert the driver, the monitor 10 is controlled to display the reference image and a warning image showing a warning message together. For example, the monitor 10 is controlled to additionally display the warning image on the reference image on the display screen 10a.

[0042] Figure 4A is a diagram showing this example, which is an example of the display in a situation where the own vehicle can pass through the intersection under a green signal. As shown in Figure 4A , on the display screen 10a, the warning image 18 is displayed overlapping the reference image. The warning image 18 includes a message for the driver informing of approaching the preceding vehicle. For example, the message "Attention ahead" is emphasized and displayed in a display color different from the reference image (the target vehicle speed image 12, the background image 15, etc.). Thus, the driver can easily recognize that it is possible to approach the preceding vehicle when driving at the target vehicle speed.

[0043] Figure 4B is a diagram showing Figure 4A a modified example of. In Figure 4B , compared with Figure 4ACompare and omit the display of the target vehicle speed image 12 that is part of the reference image. That is, a part of the image for passing assistance display at the intersection is not displayed, and the provision of passing assistance display is restricted. As a result, the driver can drive safely while paying attention to the preceding vehicle without giving priority to passing through the intersection without stopping, that is, without giving priority to driving within the target vehicle speed range.

[0044] In the driving scenario where the warning image 18 is displayed, the passing assistance display at the intersection can also be stopped. Figure 4C This is a diagram showing this example. In Figure 4C compared with Figure 4B the display of the driving action image 16 that is part of the reference image is omitted. That is, the passing assistance display is stopped. A message such as "Passing assistance display is stopped" is also displayed as the warning image 18 on the display screen 10a. As a result, the driver can drive while concentrating on the front without looking at the display screen 10a, and can prevent approaching the preceding vehicle too quickly. In this way, the display control unit 24 can also omit at least one of the target vehicle speed image 12 and the driving action image 16 when the warning image 18 is displayed.

[0045] Figure 5 This is a flowchart showing an example of the process executed by the Figure 3 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.

[0046] As Figure 5 shown, first, in S1 (S: processing step), the signal information 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 signal information includes information on the remaining time until the signal changes from green to yellow or from red to green (green signal remaining time, red signal remaining time). Also in S1, the information on the legal speed of the road being traveled is acquired with reference to the road information pre-stored in the memory. Note that the information on the legal speed of the road being traveled can also be acquired by the in-vehicle camera recognizing road signs.

[0047] Next, in S2, based on the 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 without stopping at the intersection where the signal is set or a target vehicle speed range in the case of stopping in front of the signal is calculated.

[0048] Next, in S3, it is determined whether there is a preceding vehicle within a specified distance based on the signal from the distance sensor 4. It is also possible to determine whether there is a preceding vehicle based on the image from the camera mounted on the vehicle that captures the surroundings of the vehicle. The specified distance is, for example, the distance from the current location to the traffic signal. When S3 is negative (S3: No), it proceeds to S4.

[0049] In S4, a control signal is output to the monitor 10 to display an image (reference image) of recommended driving including the target vehicle speed range calculated in S2. A control signal is output to the monitor 10, for example, as Figure 2A , Figure 2B shown, the target vehicle speed image 12, 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.

[0050] On the other hand, when S3 is affirmative (S3: Yes), it 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 obtained in S1.

[0051] Next, in S6, it is determined whether the vehicle speed Vf detected in S5 is smaller than the maximum value Va of the target vehicle speed range calculated in S2. This determination is whether the own vehicle traveling according to the recommended driving is likely to approach the preceding vehicle. When S6 is affirmative (S6: Yes), it proceeds to S7, and when it is negative (S6: No), it proceeds to S4.

[0052] 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 less than or equal to the specified value La using the inter-vehicle distance information. When S7 is affirmative (S7: Yes), it proceeds to S8, and when it is negative (S7: No), it proceeds to S4.

[0053] In S8, a control signal is output to the monitor 10 so that in addition to displaying the image (reference image) of recommended driving including the target vehicle speed range calculated in S2, a warning image 18 as shown in, for example, Figure 4A shown, is also displayed. As Figure 4B , Figure 4C shown, a control signal can also be output to the monitor 10 so that the warning image 18 is displayed in a state where part or all of the reference image is not displayed. In S8, in addition to displaying Figure 4A , Figure 4B or Figure 4C display, the speed of the preceding vehicle can also be displayed.

[0054] The operation of the driving assistance device 100 of the present embodiment is summarized as follows. As Figure 1AAs shown, when the vehicle 101 is approaching an intersection where a traffic signal 201 is installed and there is no preceding vehicle in front of the vehicle 101, for example, the following is displayed on the monitor 10 Figure 2A The reference image shown. Specifically, the target vehicle speed image 12 showing the target vehicle speed range for the vehicle 101 to pass through the intersection where the traffic signal 201 is installed without stopping and the driving action image 16 showing the driving action that can pass through the intersection without stopping are displayed together (S4). Thus, the driver can easily recognize the target vehicle speed for passing through the intersection without stopping and can perform a smooth driving action of the vehicle 101.

[0055] On the other hand, as Figure 1B shown, when there is a preceding vehicle 102 at a distance L in front of the vehicle 101, different images are displayed on the monitor 10 according to the magnitude relationship between the maximum value Va of the target vehicle speed shown by the target vehicle speed image 12 and the vehicle speed Vf of the preceding vehicle 102 and the inter-vehicle distance L between the vehicle 101 and the preceding vehicle 102. That is, when the vehicle speed Vf of the preceding vehicle 102 is equal to or higher than the maximum value Va of the target vehicle speed, the vehicle 101 is not approaching the preceding vehicle 102. In this case, instead of displaying the warning image 18, the same reference image as when there is no preceding vehicle 102 is displayed on the monitor 10 (S6→S4). Even when Vf < Va and the vehicle 101 is approaching the preceding vehicle 102, as long as the inter-vehicle distance L is larger than the specified value La, there is no need to warn the driver of approaching the preceding vehicle 102, and in this case, the same reference image as when there is no preceding vehicle 102 is also displayed (S7→S4). Therefore, the display of a part of the reference image is not blocked by the warning image 18, and the driver can easily recognize the target vehicle speed based on the displayed image.

[0056] In contrast, when the vehicle speed Vf of the preceding vehicle 102 is smaller than the maximum value Va of the target vehicle speed and the inter-vehicle distance L is equal to or smaller than the specified value La, for example, the following warning image 18 is displayed on the monitor 10 as Figure 4A shown (S8). Thus, the driver can easily recognize that when driving at the target vehicle speed to pass through the intersection without stopping, it is possible to approach (rapidly approach) the preceding vehicle 102 by more than a specified degree. Therefore, it is possible to drive while paying full attention to the inter-vehicle distance from the preceding vehicle 102, and the driving safety when performing the passing assistance display at the intersection can be improved.

[0057] Adopting this embodiment can achieve the following effects.

[0058] (1) The driving assistance device 100 of the present embodiment includes: an information acquisition unit 21 that acquires traffic signal information including the switching information of traffic signals and position information indicating the position of the own vehicle 101 relative to the traffic signal; a driving derivation unit 22 that derives recommended driving recommended to the driver based on the traffic signal information and 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 distance sensor 4 that measures the inter-vehicle distance L from the own vehicle 101 to the preceding vehicle 102 traveling ahead of the own vehicle ( Figure 3 ). When the inter-vehicle distance L measured by the distance sensor 4 is greater than a specified value La, the display control unit 24 controls the monitor 10 to display a reference image corresponding to the information on the recommended driving, and when the inter-vehicle distance L is less than or equal to the specified value La, the reference image and a warning image 18 as warning information are displayed together ( Figure 5 ).

[0059] With this structure, the driver can recognize the target vehicle speed at which the intersection can be passed without stopping, and can easily recognize that the preceding vehicle may be rapidly approached when traveling at the target vehicle speed. As a result, a driving assistance device 100 that takes into account the safety when there is a preceding vehicle 102 can be provided.

[0060] (2) The information on the recommended driving derived by the driving derivation unit 22 includes information on the recommended vehicle speed (target vehicle speed) of the own vehicle 101. The driving assistance device 100 further includes a vehicle speed detection unit 23 that detects the vehicle speed Vf of the preceding vehicle 102 based on signals from sensors 3 and 4 ( Figure 3 ). When the vehicle speed Vf detected by the vehicle speed detection unit 23 is less than the maximum value Va of the target vehicle speed range, the display control unit 24 controls the monitor 10 to display the warning image 18 ( Figure 5 ). Thus, when the own vehicle 101 may approach the preceding vehicle 102, the warning image 18 is displayed, and an alarm can be output to the driver at the optimal timing. Instead of Vf < Va, the display control unit 24 may also control the monitor 10 to display the warning image 18 when the vehicle speed of the own vehicle 101 detected by the vehicle speed sensor 3 is faster than the vehicle speed Vf detected by the vehicle speed detection unit 23. Thus, the warning image 18 is displayed when the own vehicle 101 approaches the preceding vehicle 102.

[0061] (3) The target vehicle speed V is the vehicle speed at which the own vehicle 101 can pass through the intersection provided with traffic signals without stopping. Thus, the traffic at the intersection can be made to flow smoothly while reminding the driver to pay attention when approaching the preceding vehicle.

[0062] (4) The display control unit 24 controls the monitor 10 to overlap and display the warning image 18 with the reference image when the inter-vehicle distance L is equal to or less than a specified value La. Figure 4A ) Thus, useful information for the driver can be appropriately notified within a limited display area.

[0063] The above-described embodiment can be modified in various ways. Several modification examples will be described below. In the above-described embodiment, the information acquisition unit 21 acquires the signal information including the switching information of the traffic signal transmitted from the optical beacon roadside unit 202. However, the current position of the vehicle may also be determined by the positioning sensor 2, and the information acquisition unit may acquire the 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 vehicle is detected by the positioning sensor 2. However, a radar, lidar, or camera may also be used to detect the position of the vehicle relative to the traffic signal.

[0064] In the above-described embodiment, the driving guidance unit 22 derives the recommended driving recommended to the driver based on the signal information acquired by the information acquisition unit 21 and the position information of the vehicle. Specifically, the range of the vehicle speed that the vehicle should satisfy (target vehicle speed range) and the instruction to perform a deceleration operation (deceleration instruction) are derived as part of the recommended driving. However, other recommended driving such as a lane change instruction may also be derived, and the configuration of the derivation unit is not limited to the above description. 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 outputting voice in addition to the display.

[0065] In the above-described embodiment, the reference image (first image) and the warning image 18 (second image) are displayed on the monitor 10 together on the condition that the vehicle speed Vf of the preceding vehicle is slower than the maximum value Va of the target vehicle speed and the inter-vehicle distance L is equal to or less than the specified value La. However, the vehicle speed Vf of the preceding vehicle being slower than the maximum value Va of the target vehicle speed may be omitted from the condition, and the warning image 18 may be displayed. That is, as long as the monitor is controlled such that the first image corresponding to the information of the recommended driving is displayed when the inter-vehicle distance measured by the distance sensor 4 (distance measurement unit) is greater than the specified value, and the first image and the second image as the warning information are displayed together when the inter-vehicle distance is equal to or less than the specified value, the configuration of the display control unit can be in any form.

[0066] In the above-described embodiment, a reference image is constituted by including a target vehicle speed image 12, a driving action image 16, etc. However, the traffic signal may also include information on the remaining time until the traffic signal switches from green as the first mode to yellow as the second mode, and the remaining time until the traffic signal switches from red as the first mode to green as the second mode in the reference image for display. The display of the own vehicle speed image 13 and the legal speed image 14 may also be omitted. That is, the configuration of the first image is not limited to the above. In the above-described embodiment, a prescribed text message is displayed as the warning image 18, but a graphic such as an illustration may also be displayed. The configuration of the second image is not limited to the above.

[0067] In the above-described embodiment, the configuration of the driving assistance device 100 has been described by taking the case where the own vehicle passes through an intersection provided with a traffic signal as an example. However, the traffic signal is not limited to intersections and may sometimes be 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.

[0068] The present invention can also be used as a driving assistance method, including: a step of measuring the inter-vehicle distance from the own vehicle to a preceding vehicle traveling in front of the own vehicle; a step of obtaining traffic signal information including the switching information of the traffic signal and position information indicating the position of the own vehicle relative to the traffic signal; 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 to notify the driver of the information of the recommended driving. The control step includes controlling the display unit such that when the measured inter-vehicle distance is greater than a prescribed value, a first image corresponding to the information of the recommended driving is displayed, and when the inter-vehicle distance is less than or equal to the prescribed value, the first image and a second image as warning information are displayed together.

[0069] One or more of the above-described embodiments and modification examples can be arbitrarily combined, and the modification examples can also be combined with each other.

[0070] By adopting the present invention, driving assistance considering safety can be performed in the presence of a preceding vehicle.

[0071] The present invention has been described above in conjunction with preferred embodiments. However, 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 machine information including switching information of a signal machine (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 signal machine (201); A derivation unit (22) that derives a recommended driving for the driver based on the signal machine 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 the information of the recommended driving derived by the derivation unit (22); And A distance measurement unit (4) that measures the inter-vehicle distance (L) from the own vehicle (101) to a preceding vehicle (102) traveling ahead of the own vehicle (101), The display control unit (24) controls the display unit (10) to display a first image corresponding to the information of the recommended driving when the inter-vehicle distance (L) measured by the distance measurement unit (4) is greater than a specified value (La), and to display the first image and a second image as warning information together when the inter-vehicle distance (L) is less than or equal to the specified value (La).

2. 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 information of the recommended driving speed of the own vehicle (101) is included in the information of the recommended driving derived by the derivation unit (22), The display control unit (24) controls the display unit (10) to display the second image when the vehicle speed (Vf) detected by the vehicle speed detection unit (23) is less than the maximum value (Va) of the recommended vehicle speed range.

3. The driving assistance device according to claim 2, characterized in that The recommended vehicle speed is the vehicle speed at which the own vehicle (101) can travel without stopping at the specified position.

4. The driving assistance device according to claim 3, characterized in that The first image includes a target vehicle speed image (12) showing the vehicle speed of the own vehicle (101) that can travel without stopping at the specified position and a driving action image (16) showing the driving action of the own vehicle (101) traveling without stopping at the specified position.

5. The driving assistance device according to claim 4, characterized in that The display control unit (24) controls the display unit (10) to omit at least one of the target vehicle speed image (12) and the driving action image (16) when the inter-vehicle distance (L) is less than or equal to the specified value (La).

6. The driving assistance device according to any one of claims 1 to 5, characterized in that The display control unit (24) controls the display unit (10) to display the second image overlapping the first image when the inter-vehicle distance (L) is less than or equal to the specified value (La).

7. A driving assistance method, characterized in that, Including: A step of measuring a distance (L) between the own vehicle (101) and a preceding vehicle (102) traveling ahead of the own vehicle (101); A step of obtaining traffic signal information including switching information of a traffic signal (201) that notifies 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 to be recommended to the driver based on the traffic signal information and the position information; And A step of controlling a display unit (10) to notify the driver of the information on the recommended driving, The step of the control includes controlling the display unit (10) such that a first image corresponding to the information on the recommended driving is displayed when the measured distance (L) is greater than a specified value (La), and when the distance (L) is less than or equal to the specified value (La), the first image and a second image as warning information are displayed together.

Images