JP7484597B2 - Driving Support Devices - Google Patents

Description

The technology disclosed herein belongs to the technical field of vehicle driving assistance devices that can change the vehicle speed without the driver's operation.

Conventionally, cruise control systems that change the vehicle speed without the driver's operation have been known. Some cruise control systems obtain the speed limit from a sign captured by a camera equipped in the vehicle, or obtain the speed limit for the area in which the vehicle is scheduled to travel using a navigation system, and then change the vehicle speed based on the speed limit.

For example, Patent Document 1 discloses an automatic driving control device for a vehicle that includes a vehicle control unit that is connected to be able to communicate with an actuator and configured to drive the vehicle automatically, a speed limit detection unit that is configured to output a deceleration command to the actuator via the vehicle control unit when it detects the presence of a restricted area where the speed limit is set lower than the preset driving conditions based on information obtained from outside the vehicle while the vehicle control unit is driving the vehicle automatically, and a notification signal output unit that outputs a signal to an information presentation unit to notify the occupant that the vehicle is entering a restricted area when the speed limit detection unit detects a restricted area.

JP 2019-185225 A

The system disclosed in Patent Document 1 has the advantage that the vehicle occupants are notified before the vehicle enters an area where the speed limit must be changed, allowing the occupants to know in advance that an area exists where the speed limit must be changed.

However, the system disclosed in Patent Document 1 only issues one notification, making it difficult for the occupants to recognize the current state of the vehicle, such as whether the vehicle is before decelerating or is decelerating. In autonomous driving assistance, it is important to improve the occupants' sense of security. For this reason, there is room for improvement in terms of making it easier for occupants to understand the current vehicle situation.

The technology disclosed here has been developed in light of these points, and its purpose is to enable occupants to understand the vehicle's condition as easily as possible in a vehicle in which the vehicle speed can be changed without the occupant's operation.

In order to solve the above problem, the technology disclosed herein is directed to a driving assistance device for a vehicle that can change the vehicle speed without the operation of the occupant, and includes a speed limit acquisition unit that acquires a planned speed limit, which is the speed limit on the road on which the vehicle is traveling and is the speed limit in a planned driving area in which the vehicle is predicted to travel, a vehicle speed setting unit that sets the planned speed limit as a target vehicle speed, a notification unit that is mounted on the vehicle and notifies the occupant of the vehicle of information, and a notification control unit that controls the notification by the notification unit, and the notification unit is configured to be able to notify the planned speed limit when the planned speed limit differs from the current speed limit, which is the speed limit in the area in which the vehicle is currently traveling, by a first notification, and when the planned speed limit differs from the current speed limit, by a second notification that the vehicle speed setting unit will set the target vehicle speed to the planned speed limit before the vehicle speed setting unit sets the target vehicle speed to the planned speed limit.

With this configuration, the first notification allows the occupant to recognize that the speed limit will change in the planned travel area, and at the same time, allows the occupant to recognize that the vehicle speed is not currently being changed. Furthermore, the second notification allows the occupant to recognize that the planned travel area is approaching and that the vehicle speed will begin to change. This allows the occupant to understand the current status of the vehicle heading toward the planned travel area. Therefore, the occupant can easily understand the status of the vehicle.

In the driving assistance device, the notification unit may be configured to notify the second notification by emphasizing it so that it stands out more than the first notification.

In other words, the second notification notifies the occupant of a change in the vehicle's status, and is therefore more important to inform than the first notification. For this reason, by making the second notification more noticeable than the first notification, the occupant can more easily understand the vehicle's status.

In the driving assistance device, the notification unit may be configured to further provide a third notification when the planned speed limit differs from the current speed limit, notifying the driver that the vehicle speed setting unit has set the target vehicle speed to the planned speed limit.

With this configuration, the occupant can understand that the target speed is set to the planned speed limit and that the vehicle is decelerating. Therefore, the occupant can more easily understand the vehicle's situation.

In the driving assistance device, the vehicle speed setting unit may be configured to set a target vehicle speed setting position that is a position before the planned driving area and is a position where the target vehicle speed is set to the planned speed limit when the planned speed limit is different from the current speed limit, and the notification control unit may be configured to set a position a predetermined distance before the target vehicle speed setting position calculated from the current vehicle speed and a predetermined time as a notice start position where the second notification is started.

This configuration ensures an appropriate amount of time between the start of the second notification and the vehicle entering an accelerating or decelerating state. This prevents the occupant from missing the second notification. As a result, the occupant can more easily understand the vehicle's situation.

In the driving assistance device, the first notification may be a notification that simultaneously displays the current speed limit and the planned speed limit, and the second notification may be a notification that displays the planned speed limit in a more prominent manner than the current speed limit.

With this configuration, the occupant can simultaneously understand the current speed limit and the planned speed limit, and can understand when and how much the vehicle will accelerate or decelerate. As a result, the occupant can more easily understand the vehicle's situation.

As described above, the technology disclosed herein allows the notification unit to provide different types of notifications depending on the vehicle's condition, making it easier for occupants to understand the vehicle's situation.

1 is a block diagram showing a configuration of a driving assistance device according to an exemplary embodiment 1. FIG. 11A shows an example of notifications by a notification unit, in which (a) shows a current value notification, (b) shows an acquisition notification, (c) shows a preliminary notification, and (d) shows a setting notification. 5 is a schematic diagram showing the timing of each notification by a notification unit. FIG. 11 is a part of a flowchart showing a notification setting process executed by a VCM. 11 is the remainder of the flowchart showing the notification setting process executed by the VCM. 10 is a part of a flowchart showing a vehicle speed change process executed by a VCM according to a second embodiment. 11 is the remaining part of the flowchart showing the vehicle speed change process executed by the VCM according to the second embodiment.

An exemplary embodiment will be described in detail below with reference to the drawings.

(Embodiment 1)
1 shows the configuration of a driving assistance device according to embodiment 1. This vehicle (here, an automobile) includes a power mechanism 1, a transmission 2 interposed on a power transmission path between the power mechanism 1 and front wheels 6, and a brake device 10 that brakes each of the front wheels 6 and each of the rear wheels (not shown). The power mechanism 1 is, for example, an internal combustion engine or an electric motor.

The output shaft of the power mechanism 1 is connected to the input shaft of the transmission 2, and the output shaft of the power mechanism 1 and the input shaft of the transmission 2 extend in the vehicle width direction. Power from the transmission 2 is transmitted to the differential device 4, and the power transmitted to the differential device 4 drives the left and right front wheels 6 (the left front wheel is omitted) via the left and right drive shafts 5, respectively.

The brake device 10 operates by supplying hydraulic pressure through the operation of a hydraulic control valve (not shown) controlled by a PCM (Powertrain Control Module) 60 (described later), and brakes each of the front wheels 6 and each of the rear wheels. A DSC (Dynamic Stability Control) device 9 is provided between the hydraulic control valve and the brake device 10. The DSC device 9 adjusts the braking force applied to each of the front wheels 6 and each of the rear wheels.

The vehicle is equipped with a VCM (Vehicle Control Module) 50 that controls the entire vehicle. This VCM 50 is a controller based on a well-known microcomputer, and includes a central processing unit (CPU) that executes programs, a memory consisting of, for example, RAM and ROM that stores programs and data, and an input/output (I/O) bus that inputs and outputs electrical signals.

The VCM 50 receives signals from multiple cameras 41 mounted on the vehicle that capture the external environment of the vehicle, a signal from a navigation system 42 that has vehicle position and map information, a signal from a vehicle speed sensor 43 that detects the vehicle speed, and a G sensor 44 that detects G (acceleration) input to the vehicle. Based on the above input signals, the VCM 50 outputs control signals to a display unit 61 such as a head-up display or meter, a speaker 62, and the PCM 60. Based on the signals from the VCM 50, the PCM 60 controls the operation of the power mechanism 1, the transmission 2, and the brake device 10.

In this embodiment 1, the VCM 50 is configured to be able to execute auto cruise control (hereinafter, referred to as ACC, an abbreviation of Adaptive Cruise Control) that automatically changes the vehicle speed without the operation of the occupant. The ACC control in this embodiment 1 is a control that acquires the speed limit on the road on which the vehicle travels, sets the speed limit as a target speed, and operates the power mechanism 1, the transmission 2, and the brake device 10 so that the target speed is reached. In the ACC control, the speed limit (hereinafter, referred to as the planned speed limit FV) in the planned travel area FR in which the vehicle is predicted to travel, that is, the area located ahead of the vehicle in the traveling direction, is acquired. In the ACC control, the power mechanism 1 and the like are controlled so that the vehicle speed becomes the planned speed limit FV before entering the planned travel area FR. The planned speed limit FV is acquired, for example, by photographing a sign located ahead of the vehicle in the traveling direction with the camera 41, or by acquiring map information and traffic information with the navigation system 42. The camera 41 and the navigation system 42 are examples of a speed limit acquisition unit.

The VCM 50 has a vehicle speed setting unit 51 that sets the target vehicle speed for ACC control. The vehicle speed setting unit 51 sets the planned speed limit FV acquired by the camera 41 or the like as the target vehicle speed. When the planned speed limit FV is the same as the current speed limit PV, which is the speed limit in the area in which the vehicle is currently traveling, the vehicle speed setting unit 51 outputs a control signal to the PCM 60 so that the current vehicle speed is maintained. When the planned speed limit FV differs from the current speed limit PV, the vehicle speed setting unit 51 sets the planned speed limit FV to the target vehicle speed, and outputs a control signal to the PCM 60 so that the vehicle speed becomes the planned speed limit FV before entering the planned traveling area FR.

When the planned speed limit FV is different from the current speed limit PV, the vehicle speed setting unit 51 calculates a position (hereinafter referred to as the target vehicle speed setting position) in front of the planned driving area FR where the planned speed limit FV is set as the target vehicle speed, that is, a position where acceleration/deceleration begins. First, the vehicle speed setting unit 51 acquires the position of the planned driving area FR and the position of the vehicle based on information from the navigation system 42. Next, the vehicle speed setting unit 51 calculates the distance required to decelerate (accelerate) from the current vehicle speed to the planned speed limit FV at a predetermined deceleration (acceleration). Specifically, the vehicle speed setting unit 51 calculates the time required to decelerate (accelerate) from the current vehicle speed to the planned speed limit FV at a predetermined deceleration (acceleration), and calculates the distance required for deceleration (acceleration) based on the calculated time and the current vehicle speed. Then, the vehicle speed setting unit 51 sets the target vehicle speed setting position to a position the calculated distance before the start position of the planned driving area FR. The predetermined deceleration (acceleration) is, for example, about 0.15G to 0.2G.

The VCM 50 has a notification control unit 52 for notifying the vehicle status in relation to ACC control. The notification control unit 52 transmits control signals to a display unit 61 and a speaker 62 as notification units to notify the vehicle occupants (particularly the driver) of the vehicle status.

The display unit 61 and the speaker 62 are configured to be able to notify the state of the vehicle when the vehicle is automatically accelerated or decelerated while the vehicle is executing ACC control. In this embodiment 1, the display unit 61 and the speaker 62 are configured to be able to notify the following: a current value notification indicating the current speed limit PV; an acquisition notification (first notification) notifying the planned speed limit FV when the planned speed limit FV acquired by the camera 41 or the like is different from the current speed limit PV; a notice notification (second notification) notifying the vehicle speed setting unit 51 that the target vehicle speed will be set to the planned speed limit FV before the vehicle speed setting unit 51 sets the target vehicle speed to the planned speed limit FV when the planned speed limit FV is different from the current speed limit PV; and a setting notification (third notification) notifying the vehicle speed setting unit 51 that the target vehicle speed has been set to the planned speed limit FV when the planned speed limit FV is different from the current speed limit PV.

The display unit 61 is configured to be able to display a current value display 61a relating to the current value notification, an acquisition display 61b (first notification) relating to the acquisition notification, a notice display 61c (second notification) relating to the notice notification, and a setting display 61d (third notification) relating to the setting notification. The display unit 61 is also configured to display the current vehicle speed simultaneously with each of the displays 61a to 61d.

Figure 2 shows examples of the current value display 61a, acquisition display 61b, preview display 61c, and setting display 61d displayed by the display unit 61. Figure 2(a) shows the current value display 61a, Figure 2(b) shows the acquisition display 61b, Figure 2(c) shows the preview display 61c, and Figure 2(d) shows the setting display 61d. Figure 2 shows an example in which the current speed limit PV is 100 km/h, and the planned speed limit FV in the planned driving region FR is 80 km/h, which is lower than the current speed limit PV.

In the current value display 61a, the display unit 61 displays the current speed limit PV of 100 km/h. The display at this time is, for example, a display imitating a sign indicating the maximum speed as shown in FIG. 2(a). When the vehicle enters the planned driving region FR, the current value display 61a displays the planned speed limit FV of 80 km/h.

In the acquired display 61b, the display unit 61 simultaneously displays the current speed limit PV of 100 km/h and the planned speed limit FV of 80 km/h. Like the display of the current speed limit PV, the display of the planned speed limit FV is modeled after a sign indicating a maximum speed. At this time, the display unit 61 displays the planned speed limit FV smaller than the current speed limit PV.

In the advance notice display 61c, the display unit 61 simultaneously displays the current speed limit PV and the planned speed limit FV, and displays the planned speed limit FV in an emphasized manner so that it stands out more than the current speed limit PV. Specifically, as shown in FIG. 2(c), a blinking frame is displayed around the planned speed limit FV. This makes the advance notice display 61c stand out more than the acquired display 61b.

In the setting display 61d, the display unit 61 simultaneously displays the current speed limit PV and the planned speed limit FV, and displays the planned speed limit FV in a manner different from the preview display 61c, emphasizing it so that it stands out more than the current speed limit PV. In detail, in the setting display 61d, the display unit 61 displays the planned speed limit FV in a manner that stands out more than the acquisition display 61b, but less than the preview display 61c. Specifically, as shown in FIG. 2(d), a lit frame is displayed around the display of the planned speed limit FV. Although not clear in FIG. 2, a frame of a different color than the preview display 61c may be displayed.

The speaker 62 is configured to be able to provide audio guidance such as "Set target vehicle speed to X km/h" when the display unit 61 displays the advance notice 61c in the advance notice. The audio from the speaker 62 also constitutes the advance notice. On the other hand, in this embodiment 1, the speaker 62 does not provide any audio notification in the current value notice, the acquisition notice, and the setting notice. As a result, the advance notice becomes a more prominent and emphasized notice compared to the current value notice, the acquisition notice, and the setting notice.

The notification control unit 52 transmits a control signal to the display unit 61 and the speaker 62 so as to notify the acquisition notification, the advance notice, and the setting notification at a preset timing, respectively. Specifically, the notification control unit 52 transmits a control signal to the display unit 61 so as to perform the acquisition notification at a timing when the camera 41 or the like acquires the planned speed limit FV of the planned driving area FR. The notification control unit 52 transmits a control signal to the display unit 61 and the speaker 62 so as to perform the advance notice at a timing when the vehicle reaches a notice start position set based on the target vehicle speed setting position set by the vehicle speed setting unit 51. The notice start position will be described later. The notification control unit 52 transmits a control signal to the display unit 61 so as to perform the setting notice at a timing when the vehicle reaches the target vehicle speed setting position. Note that, after the setting notice, when the vehicle speed becomes the planned speed limit FV, the notification control unit 52 may transmit a control signal to the speaker 52 so as to notify the occupant that the vehicle speed has become the planned speed limit FV. The notification at this time may be a voice guide or a buzzer sound.

When the vehicle has passed the advance notice start position at the time when the camera 41 or the like acquires the planned speed limit FV of the planned driving area FR, the notification control unit 52 transmits a control signal to the display unit 61 and the speaker 62 so as to perform the advance notice without performing the acquisition notice. In addition, when the vehicle has passed the target vehicle speed setting position at the time when the camera 41 or the like acquires the planned speed limit FV of the planned driving area FR, the notification control unit 52 transmits a control signal to the display unit 61 and the speaker 62 so as to perform the setting notice without performing the acquisition notice and the advance notice.

The notification setting unit 52 sets the advance notice start position to a position a predetermined distance before the target vehicle speed setting position calculated from the current vehicle speed and a predetermined time. When the camera 41 or the like acquires the planned speed limit FV and the planned speed limit FV is different from the current speed limit PV, the notification setting unit 52 calculates the predetermined distance and sets the planned start position. The predetermined time is set to a time during which a vehicle occupant can recognize the advance notice and predict the acceleration or deceleration of the vehicle, that is, a time longer than the average human reaction speed, and is specifically set to about one second. The predetermined distance is expressed by the following formula, for example.
Predetermined distance = current vehicle speed x predetermined time

Next, the transition of each notification will be described with reference to FIG. 3. FIG. 3 illustrates a case where the current speed limit PV is 100 km/h and the planned speed limit FV in the planned driving region FR is 80 km/h, which is lower than the current speed limit PV.

First, before the planned speed limit FV is acquired, the current value notification is performed, and the display unit 61 displays the current value display 61a showing only the current speed limit PV. Next, when the camera 41 or the like acquires the planned speed limit FV, the acquisition notification is performed. At this time, the display of the display unit 61 is switched to the acquisition display 61b, and the current speed limit PV and the planned speed limit FV are displayed on the display unit 61. Also, when the camera 41 or the like acquires the planned speed limit FV, the vehicle speed setting unit 51 calculates the target vehicle speed setting position, and the notification limiting unit 52 calculates the advance notice start position based on the target vehicle speed setting position. Next, when the vehicle passes the advance notice start position, the advance notice is performed. The display of the display unit 61 is switched from the acquisition display 61b to the advance notice display 61c, and a blinking frame is displayed in the portion showing the planned speed limit FV. Also, voice guidance is performed by the speaker 62. Then, when the vehicle passes the target vehicle speed setting position, the setting notification is performed. The display on the display unit 61 is switched from the advance notice display 61c to the setting display 61d, and a lit frame is displayed in the area showing the planned speed limit FV. When the vehicle then enters the planned driving region FR, the current value notification is again given. The display on the display unit 61 is switched from the setting display 61d to the current value display 61a, and the planned speed limit FV of 80 km/h is displayed on the display unit 61 as the current speed limit PV.

As described above, by gradually changing the notification mode depending on the vehicle's condition, the vehicle occupants can properly recognize the vehicle's condition even when the vehicle is automatically accelerated or decelerated under ACC control.

Next, the vehicle speed change process executed by the VCM 50 according to the first embodiment will be described with reference to the flowcharts in FIGS. 4 and 5. In the first embodiment, the VCM 50 executes the flowcharts shown in FIGS. 4 and 5 at a predetermined cycle (e.g., every 0.1 seconds).

First, in step S1, the VCM 50 acquires various information from the camera 41, etc.

Next, in step S2, the VCM 50 determines whether or not the planned speed limit FV has been acquired. The VCM 50 determines that the planned speed limit FV has been acquired when the camera 41 captures an image of a sign present in the planned driving area FR, or when the navigation system 42 acquires speed limit information for the planned driving area FR. If the planned speed limit FV has been acquired (YES), the VCM 50 proceeds to step S3, whereas if the planned speed limit FV has not been acquired (NO), the VCM 50 proceeds to step S4.

In step S3, the VCM 50 determines whether the acquired planned speed limit FV is different from the current speed limit PV. If the acquired planned speed limit FV is different from the current speed limit PV (YES), the VCM 50 proceeds to step S101, whereas if the acquired planned speed limit FV is the same as the current speed limit PV (NO), the VCM 50 proceeds to step S4.

In step S4, the VCM 50 sets the current speed limit PV as the target vehicle speed.

In the next step S5, the VCM 50 generates the current value notification.

Steps S101 to S111 are shown in FIG. 5. In step S101, the VCM 50 determines whether the planned speed limit FV has been set as the target vehicle speed. If the result is YES, meaning that the planned speed limit FV has been set as the target vehicle speed, the VCM 50 proceeds to step S102, whereas if the result is NO, meaning that the planned speed limit FV has not been set as the target vehicle speed, the VCM 50 proceeds to step S103.

In step S102, the VCM 50 generates the setting notification.

In step S103, the VCM 50 calculates the target vehicle speed setting position.

In the next step S104, the VCM 50 determines whether or not the vehicle has passed the target vehicle speed setting position. The VCM 50 determines whether or not the vehicle has passed the target vehicle speed setting position based on information from the navigation system 42. If the result is YES, meaning that the vehicle has passed the target vehicle speed setting position, the VCM 50 proceeds to step S105, whereas if the result is NO, meaning that the vehicle has not passed the target vehicle speed setting position, the VCM 50 proceeds to step S106.

In step S105, the VCM 50 sets the planned speed limit FV as the target vehicle speed. After step S105, the process proceeds to step S102.

In step S106, the VCM 50 calculates the advance notice start position.

In the next step S107, the VCM 50 determines whether or not the vehicle has passed the advance notice start position. The VCM 50 determines whether or not the vehicle has passed the advance notice start position based on information from the navigation system 42. If the result is YES, meaning that the vehicle has passed the advance notice start position, the VCM 50 proceeds to step S108, whereas if the result is NO, meaning that the vehicle has not passed the advance notice start position, the VCM 50 proceeds to step S110.

In step S108, the VCM 50 sets the current speed limit PV as the target vehicle speed.

In the next step S109, the VCM 50 generates the advance notice.

In step S110, the VCM 50 sets the current speed limit PV as the target vehicle speed.

In the next step S111, the VCM 50 generates the acquisition notification.

Returning to FIG. 4, in step S6 after the generation of the notification is completed, the notification generated in steps S5, S102, S109, and S111 is output and notified by the display unit 61 and the speaker 62. After step S6, the process returns.

Therefore, in this embodiment 1, in a vehicle in which the vehicle speed can be changed without the operation of the occupant, the vehicle is provided with a speed limit acquisition unit (camera 41 and navigation system 42) that acquires a planned speed limit FV, which is the speed limit on the road on which the vehicle is traveling and is the speed limit in the planned driving region FR in which the vehicle is predicted to travel, a vehicle speed setting unit 51 that sets the planned speed limit FV as a target vehicle speed, a notification unit (display unit 61 and speaker 62) that is mounted on the vehicle and notifies the occupant of the vehicle of information, and a notification control unit 52 that controls the notification by the notification unit, and the notification unit is configured to be able to provide an acquisition notification that notifies the planned speed limit FV when the planned speed limit FV differs from the current speed limit PV, which is the speed limit in the region in which the vehicle is currently traveling, and a warning notification that the vehicle speed setting unit 51 will set the target vehicle speed to the planned speed limit FV before the vehicle speed setting unit 51 sets the target vehicle speed to the planned speed limit FV when the planned speed limit FV differs from the current speed limit PV. This allows the occupant to recognize through the acquired notification that the speed limit will change in the planned driving area FR, and at the same time, recognize that the vehicle speed is not currently being changed. Furthermore, the advance notification allows the occupant to recognize that the planned driving area FR is approaching and that the vehicle speed will begin to change. This allows the occupant to understand the current status of the vehicle heading toward the planned driving area FR. Therefore, the occupant can easily understand the status of the vehicle.

In addition, in this embodiment 1, the notification unit is configured to notify the advance notification by emphasizing it so that it stands out more than the acquisition notification. This makes it possible to make the advance notification, which is of high importance to the occupant, more easily recognizable by the occupant than the acquisition notification. As a result, the occupant can more easily understand the vehicle status.

In particular, in this embodiment 1, the acquisition notification is a notification that simultaneously displays the current speed limit PV and the planned speed limit FV, and the advance notification is a notification that displays the planned speed limit FV in an emphasized manner so that it is more noticeable than the current speed limit PV. This allows the occupant to simultaneously understand the current speed limit PV and the planned speed limit FV, and to understand when and to what extent the vehicle will accelerate or decelerate. As a result, the occupant can more easily understand the vehicle's situation.

In addition, in this embodiment 1, the notification unit is configured to be capable of further issuing a setting notification notifying the driver that the vehicle speed setting unit 51 has set the target vehicle speed to the planned speed limit FV when the planned speed limit FV differs from the current speed limit PV. This allows the occupant to understand that the target speed has been set to the planned speed limit FV and that the vehicle is decelerating. This allows the occupant to more easily understand the vehicle's status.

In addition, in this embodiment 1, the vehicle speed setting unit 51 is configured to set a target vehicle speed setting position that is a position before the planned driving region FR and is a position where the target vehicle speed is set to the planned speed limit FV when the planned speed limit FV is different from the current speed limit PV, and the notification control unit 52 is configured to set a position a predetermined distance before the target vehicle speed setting position calculated from the current vehicle speed and a predetermined time as the advance notice start position where the advance notice starts. This makes it possible to appropriately secure the time from when the advance notice starts until the vehicle enters an accelerating or decelerating state, thereby preventing the occupant from missing the advance notice. As a result, the occupant can more easily understand the situation of the vehicle.

(Embodiment 2)
Hereinafter, the second embodiment will be described in detail with reference to the drawings. In the following description, the same reference numerals are used to designate the same parts as those in the first embodiment, and detailed description thereof will be omitted.

In the second embodiment, the notification system and the associated flow chart executed by the VCM 50 are different from those in the first embodiment. Specifically, in the first embodiment, the VCM 50 selects an appropriate notification according to the vehicle's position and issues the notification. On the other hand, in the second embodiment, the VCM 50 issues the acquisition notification when the planned speed limit FV is acquired, and issues the advance notification or the setting notification by adding information to the acquisition notification according to the vehicle's position. Specifically, taking the display of the display unit 61 as an example, the VCM 50 issues the acquisition display 61b when the planned speed limit FV is acquired. Then, when the vehicle passes the advance notification start position, a blinking frame is displayed in the portion of the acquisition display 61b indicating the planned speed limit FV. Furthermore, when the vehicle passes the advance notification start position, a lit frame is displayed in the portion of the acquisition display 61b indicating the planned speed limit FV.

The vehicle speed change process executed by the VCM 50 according to the second embodiment will be described with reference to the flowcharts in FIGS. 6 and 7. In the second embodiment, the VCM 50 executes the flowcharts shown in FIGS. 6 and 7 at a predetermined cycle (e.g., every 0.1 seconds).

First, in step S201, the VCM 50 acquires various information from the camera 41, etc.

Next, in step S202, the VCM 50 determines whether or not the planned speed limit FV has been acquired. The VCM 50 determines that the planned speed limit FV has been acquired when the camera 41 captures an image of a sign present in the planned driving area FR, or when the navigation system 42 acquires speed limit information for the planned driving area FR. If the planned speed limit FV has been acquired (YES), the VCM 50 proceeds to step S203, whereas if the planned speed limit FV has not been acquired (NO), the VCM 50 proceeds to step S207.

In step S203, the VCM 50 determines whether the acquired planned speed limit FV is different from the current speed limit PV. If the acquired planned speed limit FV is different from the current speed limit PV (YES), the VCM 50 proceeds to step S204, whereas if the acquired planned speed limit FV is the same as the current speed limit PV (NO), the VCM 50 proceeds to step S207.

In step S204, the VCM 50 sets the current speed limit PV as the target vehicle speed.

In the next step S205, the VCM 50 generates the acquisition notification.

In the next step S206, the VCM 50 outputs the acquisition notification. After step S206, the VCM 50 proceeds to step S301.

On the other hand, in step S207, the VCM 50 sets the current speed limit PV as the target vehicle speed.

In the next step S208, the VCM 50 generates the current value notification.

In the next step S209, the VCM 50 outputs the current value notification. After step S209, the VCM 50 returns.

Steps S301 to S311 are shown in FIG. 7. In step S301, the VCM 50 determines whether the planned speed limit FV has been set as the target vehicle speed. If the result is YES, meaning that the planned speed limit FV has been set as the target vehicle speed, the VCM 50 proceeds to step S302, whereas if the result is NO, meaning that the planned speed limit FV has not been set as the target vehicle speed, the VCM 50 proceeds to step S304.

In step S302, the VCM 50 generates information regarding the setting notification.

In the next step S303, the VCM 50 adds information about the setting notification to the acquisition notification. After step S303, the VCM 50 returns.

In step S304, the VCM 50 calculates the target vehicle speed setting position.

In step S305, the VCM 50 determines whether the vehicle has passed the target vehicle speed setting position. The VCM 50 determines whether the vehicle has passed the target vehicle speed setting position based on information from the navigation system 42. If the result is YES, meaning that the vehicle has passed the target vehicle speed setting position, the VCM 50 proceeds to step S306, whereas if the result is NO, meaning that the vehicle has not passed the target vehicle speed setting position, the VCM 50 proceeds to step S307.

In step S306, the VCM 50 sets the planned speed limit FV as the target vehicle speed. After step S306, the process proceeds to step S302.

In step S307, the VCM 50 calculates the advance notice start position.

In the next step S308, the VCM 50 determines whether or not the vehicle has passed the advance notice start position. The VCM 50 determines whether or not the vehicle has passed the advance notice start position based on information from the navigation system 42. If the result is YES, meaning that the vehicle has passed the advance notice start position, the VCM 50 proceeds to step S309, whereas if the result is NO, meaning that the vehicle has not passed the advance notice start position, the VCM 50 returns.

In step S309, the VCM 50 sets the current speed limit PV as the target vehicle speed.

In the next step S310, the VCM 50 generates information regarding the advance notice.

Then, in step S311, VCM 50 adds information about the advance notice to the acquisition notice. After step S311, VCM 50 returns.

Therefore, even in the configuration of this embodiment 2, the occupant can understand the current status of the vehicle heading toward the planned travel area FR through each notification that is given in stages. Therefore, the occupant can easily understand the status of the vehicle.

Other Embodiments
The technology disclosed herein is not limited to the above-described embodiment, and may be substituted without departing from the spirit and scope of the claims.

For example, in the above-mentioned first and second embodiments, the warning display 61c shows a blinking frame around the part showing the planned speed limit FV, but for example, an arrow pointing from the planned speed limit FV to the current speed limit PV may be blinked between the part showing the current speed limit PV and the part showing the planned speed limit FV. In this case, the setting display 61d may be configured to light up the arrow.

In addition, in the above-described first and second embodiments, the case where the target vehicle speed is changed in ACC control has been described. However, the driving assistance device according to the first and second embodiments can also be applied to the case where the target vehicle speed is changed in automatic driving of the vehicle.

The above-described embodiments are merely examples and should not be interpreted as limiting the scope of the present disclosure. The scope of the present disclosure is defined by the claims, and all modifications and variations that fall within the scope of equivalence of the claims are within the scope of the present disclosure.

The technology disclosed here is useful as a driving assistance device for a vehicle that can change the vehicle speed without the driver's operation.

41 Camera (speed limit acquisition unit)
42 Navigation system 51 Vehicle speed setting unit 52 Notification control unit 61 Display unit (notification unit)
61b Acquisition display (first notification)
61c Advance notice (second notice)
61d Setting display (third notification)
62 Speaker (notification unit)
FR Planned driving area FV Planned speed limit PV Current speed limit

Claims (3)

A driving assistance device for a vehicle capable of changing a vehicle speed without an operation by a driver,
a speed limit acquisition unit that acquires a planned speed limit, which is a speed limit on a road on which the vehicle is traveling, and is a speed limit in a planned traveling area in which the vehicle is predicted to travel;
a vehicle speed setting unit that sets the planned speed limit as a target vehicle speed;
A notification unit that is mounted on the vehicle and notifies an occupant of the vehicle of information;
A notification control unit that controls a notification by the notification unit,
The notification unit is
a first notification of the planned speed limit when the planned speed limit is different from a current speed limit that is the speed limit in an area in which the vehicle is currently traveling;
a second notification that, when the planned speed limit is different from the current speed limit, before the vehicle speed setting unit sets the target vehicle speed to the planned speed limit, the vehicle speed setting unit notifies the driver that the target vehicle speed will be set to the planned speed limit;
a third notification that notifies the driver that the vehicle speed setting unit has set a target vehicle speed to the planned speed limit when the planned speed limit is different from the current speed limit;
The device is configured to notify
The notification unit is configured to notify the second notification by emphasizing the second notification so that the second notification is more noticeable than the first notification,
a notification unit configured to notify the third notification by emphasizing the planned speed limit so that the planned speed limit is more prominent than in the first notification and less prominent than in the second notification. The driving assistance device according to claim 1 ,
the vehicle speed setting unit is configured to set a target vehicle speed setting position, which is a position before the planned travel area and is a position where a target vehicle speed is set to the planned speed limit when the planned speed limit is different from the current speed limit,
The notification control unit is configured to set a position a predetermined distance before the target vehicle speed setting position calculated from the current vehicle speed and a predetermined time as the advance notice start position for starting the second notification. The driving assistance device according to claim 1 or 2 ,
The first notification is a notification that simultaneously displays the current speed limit and the planned speed limit,
The driving assistance device according to claim 1, wherein the second notification is a notification that displays the planned speed limit in a more prominent manner than the current speed limit.

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