Patent Description:
<CIT> proposes annunciation means for performing annunciation directed to pedestrians from an automated driving vehicle. Examples of the annunciation means that are proposed include colors, text messages, sounds, and so forth, and are described as being communication means for communication directed to pedestrians.

In addition to <CIT>, <CIT> (<CIT>) is exemplified as literature indicating technical levels in the technical field of the present invention or related technical fields, at the time of filing. <CIT> discloses a vehicle projection control system and a method of controlling image projection. <CIT> discloses a road surface display device. <CIT> discloses a projection control device, a projection control method, a projection control program and a storage medium. <CIT> discloses a method and driver system for assisting a driver of a vehicle. <CIT> discloses a dynamic vehicle warning signal emission. <CIT> discloses a vehicle proximity warning apparatus and method. <CIT> discloses a road surface image-drawing system for vehicle. <CIT> discloses a vehicle safety device.

Accidents are more likely to occur at intersections with limited visibility, and non-priority intersections. At least some of these accidents are collisions between vehicles and potential traffic participants that are not visible from the vehicles. A potential traffic participant becomes a manifested traffic participant by being sensed by a vehicle. However, it is not always easy for a traveling vehicle to avoid colliding with a traffic participant that suddenly appears.

The present invention provides technology that contributes to reducing collision accidents between vehicles and potential traffic participants that are not visible to the vehicles.

The present invention provides an annunciation method according to claim <NUM>. The first annunciation is an annunciation for notifying those in the vicinity that the vehicle is traveling. By performing the first annunciation, when a potential traffic participant actually is present, the potential traffic participant can be made aware of the presence of the traveling vehicle.

The second annunciation is an annunciation for notifying those in the vicinity regarding collision avoidance actions of the vehicle. Performing the second annunciation reduces misunderstandings in communication between the manifested traffic participant and the vehicle.

Also, by giving priority to the first annunciation, priority is given to avoidance of the potential collision risk that may result in a more serious collision accident.

The foreseeing of the potential collision risk may include sensing a region in which a probability that a traffic participant is present in the direction of travel of the vehicle is high, or a region that is a blind spot to the vehicle. These regions have a higher probability for potential traffic participants to be present than other regions. Accordingly, a potential collision risk may be foreseen, assuming that such regions exist.

The foreseeing of the potential collision risk may include calculating a height of a likelihood of presence of a potential traffic participant, based on environment information. The foreseeing of the potential collision risk may also include calculating a height of a likelihood of a collision of the potential traffic participant with the vehicle, assuming that the potential traffic participant is present, based on environment information. The likelihood of the presence of potential traffic participants is affected by the environment. Further, the likelihood of collisions between potential traffic participants and vehicles is also affected by the environment. Accordingly, the accuracy of foreseeing the potential collision risk can be improved by taking the height of these likelihoods into consideration.

When the vehicle is a vehicle driven by a driver, the foreseeing of the potential collision risk may include sensing that the driver will encounter difficulty in handling the potential collision risk. In other words, even when there is a potential collision risk, the driver may be entrusted with handling the situation as long as the driver is capable of doing so.

The present invention also provides an annunciation device according to claim <NUM>.

Further, the present invention provides a storage medium according to claim <NUM>.

According to the technology of the present invention, a potential traffic participant can be made aware of the presence of a traveling vehicle by performing the first annunciation in response to a potential collision risk being foreseen. Thus, collision accidents between potential traffic participants and vehicles can be reduced.

It should be noted that when a numerical value such as a count, quantity, amount, range, etc. of each element is mentioned in the embodiment below, the invention is not limited to the mentioned numerical value unless otherwise specified in particular, or unless the numerical value is obviously limited in principle to the mentioned numerical value. Also, the structures and so forth that will be described in the following embodiment are not necessarily essential to the invention unless otherwise specified in particular, or unless the structures and so forth are obviously limited in principle to the mentioned structures and so forth.

First, a configuration of an annunciation device according to the present embodiment will be described. The annunciation device according to the present embodiment is applied to an automated driving vehicle capable of traveling autonomously.

<FIG> is a diagram illustrating an example of installation of external sensors of an automated driving vehicle <NUM> to which the annunciation device according to the present embodiment is applied. The automated driving vehicle <NUM> illustrated in <FIG> is a route bus or a bus-type vehicle used in on-demand traffic. The automated driving vehicle <NUM> will be hereinafter referred to simply as "vehicle <NUM>". Typical examples of external sensors installed in the vehicle <NUM> include cameras, Lidar (an acronym of "Laser Imaging Detection and Ranging") sensors, and radar devices. In <FIG>, a sensing range indicated by a continuous line is an example of a sensing range of a camera, sensing ranges indicated by dashed lines are examples of sensing ranges of Lidar sensors, and sensing ranges indicated by long dashed short dashed lines are examples of sensing ranges of radar devices.

In the example illustrated in <FIG>, a camera <NUM> for shooting forward is installed as an in-vehicle camera. Also, a forward Lidar sensor 22F for sensing in a forward direction, a left-forward Lidar sensor 22FL for sensing in a left-forward direction, a right-forward Lidar sensor 22FR for sensing in a right-forward direction, a rearward Lidar sensor 22R for sensing in a rearward direction, a left-rearward Lidar sensor 22RL for sensing in a left-rearward direction, and a right-rearward Lidar sensor 22RR for sensing in a right-rearward direction, are installed as in-vehicle Lidar sensors. Also, a left-forward radar device 24FL for sensing in the left-forward direction, a right-forward radar device 24FR for sensing in the right-forward direction, a left-rearward radar device 24RL for sensing in the left-rearward direction, and a right-rearward radar device 24RR for sensing in the right-rearward direction, are installed as in-vehicle radar devices.

An automated driving system of the vehicle <NUM> recognizes the state of the surroundings, using the multiple types of external sensors described above, and causes the vehicle <NUM> to autonomously travel based on recognition results thereof. Specifically, the automated driving system estimates the position thereof by comparison with map information, based on information from the Lidar sensors. The automated driving system also dynamically tracks obstructions, based on information from the radar devices and the Lidar sensors, performs fusion thereof, and distinguishes lanes based on the results of the fusion. At this time, basic recognition of three-dimensional objects is performed by the Lidar sensors, and measurement of distances to moving objects is performed by the radar devices. A travel plan for causing the vehicle <NUM> to safely travel in compliance with traffic regulations is created based on localization results, lane distinguishing results, map information including traveling routes, traffic light information recognized by the camera, a target route decided by an automotive navigation system, and so forth.

The automated driving system generates a target course based on the travel plan. The target course is a travel course to be ultimately followed by the vehicle <NUM>, and is decided taking into consideration collision with an obstruction that is situated forward of the vehicle <NUM> and is sensed by the external sensors. The target course includes a set of target positions of the vehicle <NUM> on a road where the vehicle <NUM> is traveling, and target speeds at the respective target positions. The automated driving system calculates deviations (lateral deviation, yaw angle deviation, speed deviation, and so forth) between the vehicle <NUM> and the target course, and controls steering, braking, and driving of the vehicle <NUM> to reduce the deviations, in order to cause the vehicle <NUM> to follow the target course.

The annunciation device according to the present embodiment uses the multiple types of external sensors for use in the automated driving system as information acquisition devices for acquiring information related to the state of the surroundings of the vehicle <NUM>. Among the external sensors serving as the information acquisition devices, the Lidar sensors are mainly used for sensing three-dimensional objects in the surroundings of the vehicle <NUM>. Note however, that cameras or radar devices may be used as sensing means instead of the Lidar sensors, or cameras or radar devices may be used as sensing means in combination with the Lidar sensors.

The annunciation device according to the present embodiment includes an externally-directed annunciator that performs annunciation directed to the outside of the vehicle <NUM>. In the present embodiment, the externally-directed annunciator is configured as a display panel that presents visual information. <FIG> are diagrams illustrating installation examples of the display panels to the vehicle <NUM>.

<FIG> schematically illustrates an external view of the vehicle <NUM> from the right-forward side. As illustrated in <FIG>, a front display panel 30F is attached to a front face 12F of the vehicle <NUM>. The front display panel 30F is a display panel that extends in a width direction of the vehicle <NUM>, between headlights thereof. Also, a right-side display panel 30SR is attached to a right-side face 12SR of the vehicle <NUM>. The right-side display panel 30SR is a display panel that extends in a front-rear direction of the vehicle <NUM>, in a range from a right front wheel 14FR to a right rear wheel 14RR.

<FIG> schematically illustrates an external view of the vehicle <NUM> from the left-rearward side. As illustrated in <FIG>, a rear display panel 30R is attached to a rear face 12R of the vehicle <NUM>. The rear display panel 30R is a display panel that extends in the width direction of the vehicle <NUM>, between taillights thereof. Also, a left-side display panel 30SL is attached to a left-side face 12SL of the vehicle <NUM>. The left-side display panel 30SL is a display panel that extends in the front-rear direction of the vehicle <NUM>, in a range from a left front wheel 14FL to a left rear wheel 14RL. The left-side display panel 30SL is divided into a plurality of parts at a boarding door <NUM>.

As described above, the four display panels 30F, 30R, 30SR, and 30SL making up the externally-directed annunciator are attached so as to face in different directions from each other. Accordingly, traffic participants present in the vicinity of the vehicle <NUM> can view at least one of the display panels 30F, 30R, 30SR, and 30SL, from any direction. Each of the display panels 30F, 30R, 30SR, and 30SL is, for example, a display panel capable of displaying contents that can be changed, such as a liquid crystal display panel, an organic electroluminescence (EL) display panel, a light-emitting diode (LED) display panel, or the like.

<FIG> is a diagram illustrating a system configuration of the annunciation device according to the embodiment of the present invention. The annunciation device includes a control device <NUM>. Information obtained by the multiple types of external sensors installed in the vehicle <NUM>, i.e., the camera <NUM>, the Lidar sensors 22F, 22FL, 22FR, 22R, 22RL, and 22RR, and the radar devices 24FL, 24FR, 24RL, and 24RR, is transmitted to the control device <NUM>. The external sensors are connected to the control device <NUM> by an in-vehicle network. The display panels 30F, 30R, 30SR, and 30SL installed in the vehicle <NUM> are also connected to the control device <NUM> by the in-vehicle network. The contents displayed on the display panels 30F, 30R, 30SR, and 30SL are individually controlled based on control signals transmitted from the control device <NUM>.

Devices such as a data communication module <NUM>, an automotive navigation system <NUM>, an automated/manual changeover switch <NUM>, and so forth, are connected to the control device <NUM>. The data communication module <NUM> is connected to a server via a communication network, and acquires map information necessary for automated driving, from a road features map, a tracking map, a traffic rules map, and a travel route map, which are on the server, the map information then being provided to the control device <NUM>. The automotive navigation system <NUM> creates a route plan from a navigation map, and provides the route plan to the control device <NUM>. The automated/manual changeover switch <NUM> is a switch for switching between automated driving and manual driving. Switching can be performed at the request of the automated driving system or by judgment of a driver him/herself.

The control device <NUM> is an in-vehicle computer including a processor <NUM> and memory <NUM>. The control device <NUM> may be made up of a single electronic control unit (ECU), or may be an aggregate of a plurality of ECUs. The control device <NUM> may be an ECU that also serves as an ECU making up the automated driving system, or may be another ECU. The memory <NUM> stores various types of programs <NUM> that can be executed by the processor <NUM>, and data related to the programs <NUM>. The memory <NUM> here may include, in addition to memory in a narrow sense such as random access memory (RAM), a data storage device typified by a magnetic disk such as a hard disk drive (HDD), an optical disc such as a digital versatile disc (DVD), a flash memory storage device such as a solid-state drive (SSD), and so forth.

The programs <NUM> stored in the memory <NUM> include an annunciation program <NUM>. The annunciation program <NUM> is a program that causes the control device <NUM> to execute annunciation using the in-vehicle annunciation device, i.e., the display panels 30F, 30R, 30SR, and 30SL. The annunciation program <NUM> includes an annunciation determination routine <NUM>, a manifested collision risk determination routine <NUM>, a potential collision risk determination routine <NUM>, and a driver state risk estimation routine <NUM>. The annunciation program <NUM> including these routines <NUM>, <NUM>, <NUM>, and <NUM>, is executed by the processor <NUM>, thereby executing an annunciation method according to the present embodiment by the annunciation device.

Next, an overview of the annunciation method to be executed by the annunciation device according to the present embodiment will be described with reference to <FIG>. Note that in each of the examples illustrated in <FIG>, the vehicle <NUM> is assumed to be autonomously traveling by the automated driving system.

In the example illustrated in <FIG>, there is an intersection <NUM> ahead on the road on which the vehicle <NUM> is traveling. Visibility of a side road connecting to the intersection <NUM> is poor, and a region of the side road is a blind spot to the vehicle <NUM>. Even when a traffic participant, such as a pedestrian or a bicycle, is present in the blind spot region, the external sensors of the vehicle <NUM> cannot sense the traffic participant. There is a possibility that the vehicle <NUM> will not be able to avoid a collision with the traffic participant in a situation in which the vehicle <NUM> is passing through the intersection <NUM> and the traffic participant, who is not sensed, suddenly enters the roadway.

Accordingly, in the annunciation method according to the present embodiment, when there is the intersection <NUM> ahead of the vehicle <NUM>, the control device <NUM> determines that a potential traffic participant <NUM> is present at the intersection <NUM>. The control device <NUM> then determines a potential collision risk between the potential traffic participant <NUM> and the vehicle <NUM>. A potential collision risk is a potentially-existing collision risk, and the potential traffic participant <NUM> is not a traffic participant that is actually present in front of the vehicle <NUM>. Accordingly, collision avoidance action is not taken by the collision avoidance system installed in the vehicle <NUM>. Thus, when foreseeing a potential collision risk, the control device <NUM> performs a first annunciation for avoidance of the potential collision risk. The first annunciation is annunciation for notifying those in the vicinity that the vehicle <NUM> is traveling. Specifically, "passing" or "starting to move" is conspicuously displayed on the display panels. By performing such a display, when the potential traffic participant <NUM> notices the presence of the vehicle <NUM>, the potential traffic participant <NUM> can quickly recognize that the vehicle <NUM> is traveling, i.e., it is dangerous unless he/she stops.

In the example illustrated in <FIG>, a pedestrian is walking ahead on the road on which the vehicle <NUM> is traveling. The pedestrian is a manifested traffic participant <NUM> whose presence is confirmed by the external sensors of the vehicle <NUM>. Once the presence of the manifested traffic participant <NUM> is confirmed, a manifested collision risk between the manifested traffic participant <NUM> and the vehicle <NUM> is determined. The manifested collision risk is a collision risk that has already been manifested, and accordingly the vehicle <NUM> is required to take action for avoidance thereof. Hence, when a manifested collision risk is sensed, the collision avoidance system takes collision avoidance actions with respect to the manifested traffic participant <NUM>. Specifically, the vehicle <NUM> decelerates toward a position short of the manifested traffic participant <NUM>, and slows down to yield or stops when near to the manifested traffic participant <NUM>, and starts moving when there is no longer a danger of collision.

In the annunciation method according to the present embodiment, the control device <NUM> performs a second annunciation for avoiding the manifested collision risk, in conjunction with the collision avoidance action by the collision avoidance system. The second annunciation is an annunciation for notifying those in the vicinity with regard to collision avoidance actions of the vehicle <NUM>. Specifically, "decelerating" is displayed on the display panel while the vehicle <NUM> is decelerating, "yielding" is displayed on the display panel while the vehicle <NUM> is slowing down to yield, and "stopping" is displayed on the display panel while the vehicle <NUM> is stopped. When the vehicle <NUM> is going to accelerate, "accelerating" is displayed on the display panel from several seconds before accelerating. Performing such displays reduces misunderstandings in communication between the manifested traffic participant <NUM> and the vehicle <NUM>.

In the example illustrated in <FIG>, there is the intersection <NUM> ahead on the road on which the vehicle <NUM> is traveling, and the potential traffic participant <NUM> is hidden in the intersection <NUM>. Also, the manifested traffic participant <NUM> is sensed further ahead, on the other side of the intersection <NUM>. In this case, a potential collision risk between the potential traffic participant <NUM> and the vehicle <NUM> is foreseen, and subsequently, a manifested collision risk between the manifested traffic participant <NUM> and the vehicle <NUM> is also sensed.

In the annunciation method according to the present embodiment, the first annunciation is given with priority over the second annunciation, as long as the potential collision risk continues. In the example illustrated in <FIG>, even at a position where "decelerating" would be displayed on the display panels when there is only a manifested collision risk, "passing" or "starting to move" is displayed on the display panels when there is a potential collision risk. Thereafter, when the vehicle <NUM> enters the intersection <NUM> and the potential collision risk is gone, the display on the display panels is switched from "passing" or "starting to move" to "decelerating". By giving priority to the first annunciation in this way, priority is given to avoidance of the potential collision risk that may result in a more serious collision accident.

In the example illustrated in <FIG>, the manifested traffic participant <NUM> is sensed ahead on the road on which the vehicle <NUM> is traveling. Also, there is the intersection <NUM> further beyond the manifested traffic participant <NUM>, and the potential traffic participant <NUM> is hidden in the intersection <NUM>. In this case, a manifested collision risk between the manifested traffic participant <NUM> and the vehicle <NUM> is sensed, and subsequently, a potential collision risk between the potential traffic participant <NUM> and the vehicle <NUM> is also foreseen.

In the annunciation method according to the present embodiment, even when the second annunciation is being performed due to sensing of a manifested collision risk, priority is given to the first annunciation over the second annunciation when a potential collision risk is foreseen. In the example illustrated in <FIG>, "decelerating" is displayed on the display panel while only the manifested collision risk is sensed. However, at the point in time that a potential collision risk is foreseen, the display on the display panel is switched from "decelerating" to "passing" or "starting to move". By giving priority to the first annunciation in this way, priority is given to avoidance of the potential collision risk that may result in a more serious collision accident.

Thus, in the annunciation method according to the present embodiment, when a potential collision risk is foreseen, the first annunciation is made to notify those in the vicinity that the vehicle <NUM> is traveling. In the examples illustrated in <FIG>, <FIG> and <FIG>, "passing" or "starting to move" is displayed on the display panels as the first annunciation. When this display catches the eye of the potential traffic participant <NUM>, the potential traffic participant <NUM> can instantly recognize the presence of the vehicle <NUM> that is traveling. Thus, collision accidents between the vehicle <NUM> and potential traffic participants <NUM> that are not visible to the vehicle <NUM> are reduced. Also, the first annunciation is given priority over the second annunciation as long as the potential collision risk continues, and accordingly the potential collision risk, in which a more serious collision accident may occur, is preferentially avoided.

The annunciation method according to the present embodiment is executed by the control device <NUM>, by the processor <NUM> executing the annunciation program <NUM>. Logic of the annunciation program <NUM> for implementing the annunciation method according to the present embodiment will be described below.

<FIG> and <FIG> are flowcharts showing logic of the annunciation program <NUM>. Of these, <FIG> shows logic for automated driving, and <FIG> shows logic for manual driving. The logic for automated driving is selected when the vehicle <NUM> is automatically driven by the automated driving system, and the logic for manual driving is selected when the vehicle <NUM> is manually driven by the driver. The logic for automated driving and the logic for manual driving have much in common, and there are only some partial differences.

First, the logic for automated driving will be explained with reference to <FIG>. According to the flowchart shown in <FIG>, first, in step S01, manifested collision risk determination processing is performed. The manifested collision risk determination processing is performed by the manifested collision risk determination routine <NUM> that is a subroutine of the annunciation program <NUM>.

<FIG> is a flowchart showing logic of the manifested collision risk determination routine <NUM>. According to this flowchart, first, in step S21, determination is made regarding whether the external sensors of the vehicle <NUM> recognize a traffic participant. When no traffic participant is recognized, determination is made that there is no manifested collision risk, and the manifested collision risk determination routine <NUM> ends.

When a traffic participant is recognized, determination is made in step S22 whether deceleration is below a certain value. The certain value is a limit of deceleration at which determination can be made that the vehicle <NUM> is decelerating due to braking. Deceleration lower than the certain value means that the vehicle <NUM> is decelerating due to braking. When there is a risk of collision with respect to a traffic participant that is recognized, collision avoidance actions are taken by the collision avoidance system. Accordingly, when the vehicle <NUM> is not decelerating, determination is made that there is no manifested collision risk, and the manifested collision risk determination routine <NUM> ends.

When the vehicle <NUM> is decelerating, probability computation of a manifested collision risk is performed in step S23. Specifically, the movement of the traffic participant over a certain amount of time thereafter is predicted from the movement of the traffic participant that is recognized. The movement of the traffic participant over a certain amount of time thereafter can be deemed to follow a Gaussian distribution that includes the influence of past movement history. The probability that the traffic participant will appear in front of the vehicle <NUM> is calculated from the predicted movement over the certain amount of time.

Returning to <FIG>, description of the flowchart of the annunciation program <NUM> will be continued. In step S02, determination is made regarding whether sudden braking will be performed with respect to the traffic participant recognized in step S01. As a specific example, Time to Reach (TTR), which is the time until the traffic participant recognized in step S01 will arrive at the vehicle <NUM>, and Time to Collision (TTC), which is the time until the vehicle <NUM> will collide with the traffic participant, are compared. When TTR is greater than TTC as a result of the comparison, determination is made that sudden braking will not be performed, and when TTR is no greater than TTC, determination is made that sudden braking will be performed. When no traffic participant is recognized in step S01, determination is made that sudden braking will not be performed.

When determination is made that sudden braking will occur, the processing of step S08 is executed. In step S08, a passing display is made. The passing display is to display "passing" or "starting to move" on the display panels. When the determination in step S02 is negative, the collision avoidance system performs sudden braking to avoid a collision. However, when the display on the display panels is set to "decelerating" or "stopping," there is a risk that the traffic participant will be relieved, and will delay avoidance actions. On the other hand, by displaying "passing" or "starting to move" on the display panels, it can be anticipated that the traffic participant will be notified of the presence of the vehicle <NUM> that is approaching, and will be prompted to take avoidance actions.

When determination is made in step S02 that sudden braking will not be performed, the processing of step S03 is executed. In step S03, determination is made regarding whether there is a manifested collision risk. Whether there is a manifested collision risk is determined based on the results of the probability computation of the manifested collision risk performed in step S01. When the probability value of the manifested collision risk is no less than a certain value, determination is made that there is a manifested collision risk. When determination is made that there is no manifested risk of collision, the routine ends without performing annunciation by the display panels.

When determination is made in step S03 that there is a manifested collision risk, potential collision risk determination processing is performed in step S04. The potential collision risk determination processing is performed by the potential collision risk determination routine <NUM> that is a subroutine of the annunciation program <NUM>. In the potential collision risk determination routine <NUM>, a probability value of the potential collision risk is computed.

<FIG> is a flowchart showing the logic of the potential collision risk determination routine <NUM>. According to this flowchart, first, in step S31, a region in which there is a high probability that a traffic participant will be present in the direction of travel of the vehicle <NUM>, or an area that is a blind spot from the vehicle <NUM>, is sensed. In addition to intersections, such as in the example illustrated in <FIG>, objects of sensing include regions where there are crosswalks, regions where there are traffic lights, regions where the road width is narrow, and so forth. These regions have a higher probability for potential traffic participants to be present than other regions. Accordingly, a base probability value of the potential collision risk is computed, assuming that such regions exist.

Next, in step S32, the height of the likelihood of potential traffic participants to be present is calculated based on environment information of the vehicle <NUM>. The probability of presence of potential traffic participants is affected by the environment. Schools, train stations, and residential areas are examples of environments in which the probability of the presence of potential traffic participants is high. A weighting value to be applied to the base probability value is decided according to the presence or absence of schools or the like. Also, the weighting value is increased further the closer to a school or the like.

Next, in step S33, the height of the likelihood of collision between the potential traffic participant and the vehicle is calculated based on the environment information of the vehicle <NUM>, assuming that the potential traffic participant is present. The probability of collision between the potential traffic participant and the vehicle also is affected by the environment. An example of an environment that increases the probability of a collision is a shielding object that shields from view a side street connecting to an intersection. A weighting value to be applied to the base probability value is decided according to the presence or absence of a shielding object. Also, the weighting value is increased when the height of the shielding object is no less than a certain value.

Then, in step S34, the probability of a potential traffic participant who is not visible to the vehicle <NUM> appearing in front of the vehicle <NUM> is calculated based on the calculation results of steps S31 to S33. Specifically, the probability value of the potential collision risk is computed by multiplying the weighting values calculated in steps S32 and S33 by the base value calculated in step S31.

Returning to <FIG>, description of the flowchart of the annunciation program <NUM> will be continued. In step S05, determination is made regarding whether there is a potential collision risk. Whether there is a potential collision risk is determined based on the results of the probability computation of the potential collision risk performed in step S04. When the probability value of the potential collision risk is no less than a certain value, determination is made that there is a potential collision risk.

When determination is made that there is no potential collision risk, the processing of step S06 is executed. In step S06, normal annunciation processing is performed to handle the manifested collision risk. Normal annunciation processing is performed by an annunciation determination routine <NUM> that is a subroutine of the annunciation program <NUM>. In the annunciation processing by the annunciation determination routine <NUM>, the display on the display panel is changed from "decelerating" to "yielding" or "stopping", and further changed to "accelerating", in accordance with the distance between the vehicle <NUM> and the manifested traffic participant (see <FIG>).

When determination is made that there is a potential collision risk, the processing of step S07 is executed. In step S07, a passing display is executed to display "passing" or "starting to move" on the display panel. By performing such a "passing" or "starting to move" display on the display panels, when the potential traffic participant <NUM> notices the presence of the vehicle <NUM>, the potential traffic participant <NUM> can quickly recognize that the vehicle <NUM> is traveling, i.e., it is dangerous unless he/she stops.

Next, the logic for manual driving will be described with reference to <FIG>. The difference between the logic for manual driving and the logic for automated driving is that the processing of steps S10 and S11 are added. According to the flowchart shown in <FIG>, the content of which does not form a part of the invention as such, when determination is made that there is a potential collision risk in step S05, the processing of step S07 is not executed immediately, and driver state risk estimation processing is performed in step S10. The driver state risk estimation processing is performed by the driver state risk estimation routine <NUM> that is a subroutine of the annunciation program <NUM>.

<FIG> is a flowchart showing logic of the driver state risk estimation routine <NUM>. According to this flowchart, in step S41, drowsiness of the driver is determined from movement of the eyelids and the line of sight of the driver. Also, in step S42, each state of operation of an accelerator pedal, a brake pedal, and a steering wheel, performed by the driver is determined, and in step S43, the orientation of the face of the driver is determined. Then, in step S44, probability computation of the driver state risk is performed, based on the determination results of steps S41 to S43. The driver state risk means the risk that it is difficult for the driver to handle the potential collision risk.

Returning to <FIG>, description of the flowchart of the annunciation program <NUM> will be continued, the content of which does not form a part of the invention as such. In step S11, determination is made regarding whether there is a driver state risk. Whether there is a driver state risk is determined based on the results of the probability computation of the driver state risk performed in step S10. When the probability value of the driver state risk is no less than a certain value, determination is made that there is a driver state risk.

When determination is made that there is no driver state risk, the processing of step S06 is executed. That is to say, even when determination is made in step S05 that there is a potential collision risk, normal annunciation processing is performed as long as the driver is in a state of being capable of handling the potential collision risk. In other words, during manual driving, even when there is a potential collision risk, the driver is entrusted with handling the situation as long as the driver is capable of doing so.

When determination is made that there is a driver state risk, the processing of step S07 is then executed. That is to say, when determination is made in step S05 that there is a potential collision risk and the driver is in a state where handling of the potential collision risk is difficult, the passing display of "passing" or "starting to move" is made on the display panels. During manual driving, foreseeing of a potential collision risk includes that the driver will encounter difficulty in handling thereof, and the first annunciation is performed only when the driver will encounter difficulty in handling the situation.

The processor <NUM> executes the annunciation program <NUM> of the contents described above according to a predetermined execution cycle, whereby the annunciation method according to the the invention is executed by the control device <NUM> that makes up the annunciation device. By executing the annunciation method according to the invention, the first annunciation is performed in response to foreseeing a potential collision risk. This enables the potential traffic participant to be aware of the presence of the vehicle that is traveling, thereby reducing collision accidents between vehicles and potential traffic participants that are not visible from the vehicle.

The annunciation device according to the embodiment described above is applied to bus-type automated driving vehicles. However, the automated driving vehicle to which the annunciation device according to the present invention is applied may be, for example, a privately owned vehicle, a ride-share vehicle in which multiple people ride together, or a public transportation vehicle such as a bus or a taxi. Furthermore, the annunciation device according to the present invention is also applicable to remotely operated vehicles that are remotely driven by a remote operator.

Also, although the annunciation device according to the above embodiment includes the display panels, an audio output device having one or more speakers may also be used as the annunciator. That is to say, annunciation by sound may be performed. For example, an audio output device having a plurality of directional speakers pointing in different directions may be provided, with annunciation being performed limiting the first annunciation to the direction of the potential traffic participant. The annunciation using the display panel and the annunciation using the audio output device may be performed together.

Claim 1:
An annunciation method comprising:
foreseeing a potential collision risk between a vehicle (<NUM>) and a potential traffic participant (<NUM>) predicted to be present ahead in a direction of travel of the vehicle (<NUM>);
performing a first annunciation notifying those in a vicinity that the vehicle (<NUM>) is traveling, using an externally-directed annunciator installed in the vehicle (<NUM>), in response to the potential collision risk being foreseen;
sensing a manifested collision risk between the vehicle (<NUM>) and a manifested traffic participant (<NUM>) of which presence is confirmed ahead in the direction of travel of the vehicle (<NUM>);
performing a second annunciation notifying those in the vicinity regarding collision avoidance actions of the vehicle, using the externally-directed annunciator, in response to the manifested collision risk being sensed;
wherein the externally-directed annunciator includes at least one display panel which is attached to at least one face of the vehicle;
the method further comprising
prioritizing the first annunciation over the second annunciation as long as the potential collision risk continues,
the method being characterized in that
when the first annunciation is prioritized, "passing" or "starting to move" is displayed as the first annunciation on the at least one display panel; and
when the first annunciation is not prioritized, the second annunciation is performed and "decelerating" or "yielding" is displayed, as the second annunciation, instead on the at least one display panel.