JP7772004B2 - Vehicle control device, vehicle control method, and vehicle control computer program - Google Patents

Description

The present invention relates to a vehicle control device, a vehicle control method, and a computer program for vehicle control.

Technology is being researched that references map information to perform autonomous vehicle driving control. However, the accuracy of the information displayed in such map information is not always sufficient. Therefore, technology has been proposed that performs autonomous movement control based on the accuracy or reliability of the map (see Patent Document 1).

The mobile body control device disclosed in Patent Document 1 suppresses the movement speed of the mobile body when the deviation in lateral distance between a first target movement path displayed on an external map and a second target movement path generated using external world information, movement information of the mobile body, or a map for autonomous movement generated based on the external world information and movement information exceeds a predetermined value. However, even if the deviation in lateral distance is large, this mobile body control device maintains the initial setting speed of the mobile body in areas where the deviation in curvature at each location between the second target movement path on the map for autonomous movement and the first target movement path on the external map is small.

Patent No. 6970807

As with the technology described above, multiple maps may be available for use in autonomous vehicle driving control. In such cases, when the vehicle's control device switches from one map actually used to another, the vehicle's behavior may become unstable. This unstable vehicle behavior may cause the driver of the vehicle to feel uneasy or uncomfortable.

Therefore, the present invention aims to provide a vehicle control device that can reduce the driver's anxiety or discomfort when the map used for vehicle driving control is switched.

According to one embodiment, a vehicle control device is provided. This vehicle control device has a storage unit that stores a first map and a second map that represent information about roads, and a control unit that controls vehicle driving based on the first map or the second map. When the map used to control vehicle driving is switched from the first map to the second map, the control unit controls the acceleration/deceleration so that the absolute value of the change in acceleration/deceleration per unit time for the transition from vehicle driving behavior based on the first map to vehicle driving behavior based on the second map is equal to or less than a predetermined threshold.

This vehicle control device preferably further includes a detection unit that detects a preceding vehicle traveling ahead of the vehicle based on sensor signals representing the vehicle's surroundings and estimates the distance between the vehicle and the preceding vehicle, and a determination unit that determines whether the preceding vehicle is traveling in the same lane as the vehicle, based on a first map or a second map. Furthermore, when the map used to control the vehicle's traveling is switched from the first map to the second map, if the determination result of the lane in which the preceding vehicle is traveling changes from outside the same lane to the same lane, and the distance between the vehicle and the preceding vehicle is less than a predetermined distance, the control unit preferably suppresses the amount of change in the vehicle's deceleration per unit time until the distance between the vehicle and the preceding vehicle reaches a predetermined distance below a predetermined threshold.

It is also preferable that this vehicle control device further includes a detection unit that detects nearby vehicles traveling in an adjacent lane adjacent to the lane in which the vehicle is traveling. In this case, if the first map being used to control the vehicle's travel shows a merging point where an adjacent lane merges into the vehicle's travel lane within a predetermined distance from the vehicle, the control unit reduces the vehicle's speed below a predetermined speed so that the distance between the vehicle and the nearby vehicles remains equal to or greater than a predetermined distance even when the nearby vehicle merges into the vehicle's travel lane. On the other hand, if the second map does not show a merging point and the map being used to control the vehicle's travel is switched from the first map to the second map while the vehicle's speed is being decelerated, it is preferable that the control unit suppress the amount of change per unit time in the vehicle's acceleration as the vehicle accelerates to a predetermined speed or less.

Alternatively, in this vehicle control device, the control unit preferably generates a planned driving route based on either the first map or the second map, whichever is currently being used to control the vehicle's driving, so that the vehicle passes through a predetermined position in the width direction of the lane in which the vehicle is driving, and controls the vehicle to drive along the generated planned driving route. In this case, if the position of the planned driving route in the width direction changes when the map used to control the vehicle's driving is switched from the first map to the second map, the control unit preferably suppresses the amount of change per unit time in the vehicle's acceleration in the width direction until the vehicle's position reaches the planned driving route generated based on the second map to below a predetermined threshold.

According to another embodiment, a vehicle control device is provided. The vehicle control device includes a memory unit that stores a first map showing information about roads surrounding the vehicle and a second map showing information about the roads but with lower accuracy than the first map, and a control unit that controls the vehicle based on the first map or the second map to drive the vehicle in a position adjacent to the lane in which the vehicle is traveling and that is spaced from the center of the lane by a predetermined offset amount in a direction away from the adjacent lane in which another vehicle is traveling, based on the first map or the second map. The control unit then sets the predetermined offset amount when controlling the vehicle's traveling based on the second map to be smaller than the predetermined offset amount when controlling the vehicle's traveling based on the first map.

According to another embodiment, a vehicle control method is provided. This vehicle control method includes controlling vehicle travel based on a first map representing information about roads or a second map representing information about the roads. Controlling vehicle travel includes, when the map used to control vehicle travel is switched from the first map to the second map, controlling acceleration/deceleration so that the absolute value of the change in vehicle acceleration/deceleration per unit time for transitioning from vehicle travel behavior based on the first map to vehicle travel behavior based on the second map is equal to or less than a predetermined threshold.

According to yet another embodiment, a computer program for controlling a vehicle is provided. The computer program for controlling a vehicle includes instructions for causing a processor mounted on the vehicle to control vehicle travel based on a first map representing information about roads or a second map representing information about the roads. Controlling vehicle travel includes controlling acceleration/deceleration when the map used to control vehicle travel is switched from the first map to the second map, so that the absolute value of the change in acceleration/deceleration per unit time for transitioning from vehicle travel behavior based on the first map to vehicle travel behavior based on the second map is equal to or less than a predetermined threshold.

The vehicle control device disclosed herein has the advantage of being able to reduce driver anxiety or discomfort when the map used for vehicle driving control is switched.

1 is a schematic configuration diagram of a vehicle control system in which a vehicle control device is implemented. 1 is a hardware configuration diagram of an electronic control device that is one embodiment of a vehicle control device. FIG. 2 is a functional block diagram of a processor of an electronic control unit related to vehicle control processing. 10A and 10B are diagrams illustrating an example in which the determination result of the positional relationship between a vehicle and a preceding vehicle changes before and after the map used for cruise control is switched. FIG. 5 is a diagram showing an example of the relationship between the change over time of the inter-vehicle distance between the vehicle and the preceding vehicle and the change over time of the deceleration of the vehicle in the example shown in FIG. 4 . 10A and 10B are diagrams illustrating an example in which the predicted behavior of a nearby vehicle changes before and after a map used for cruise control is switched. FIG. 7 is a diagram showing an example of the relationship between the presence or absence of a merging point shown on a map used for cruise control and the change in acceleration/deceleration of the vehicle over time in the example shown in FIG. 6 . 10A and 10B are diagrams illustrating an example in which the positions of lane markings shown on a map change before and after a map used for cruise control is switched. FIG. 9 is a diagram showing an example of the relationship between the lateral position of the planned travel route and the change over time in the lateral acceleration of the vehicle in the example shown in FIG. 8 . 10 is an operational flowchart of a vehicle control process accompanying switching of a map used for driving control. 10A and 10B are diagrams showing the relationship between a map used for cruise control and an offset amount in the VLO function, respectively. 10 is an operational flowchart of a vehicle control process related to a VLO function according to a modified example.

Below, with reference to the figures, we will explain a vehicle control device, a vehicle control method executed on the vehicle control device, and a computer program for vehicle control. This vehicle control device controls vehicle driving using one of two maps that represent information about roads. More specifically, when the map used to control vehicle driving is switched from one map to the other, this vehicle control device controls the acceleration/deceleration so that the absolute value of the change in the vehicle acceleration/deceleration per unit time required to transition from the vehicle's driving behavior based on one map to the vehicle's driving behavior based on the other map is below a predetermined threshold.

In this embodiment, each of the two maps includes information about roads that is used to generate the planned driving route, such as information about road markings such as lane markings, information about the types of features such as curbs, road signs, and roadside signs, and information about the locations of these features.

Furthermore, it is preferable that the map with the higher accuracy of information regarding roads shown on the two maps be set as the map to be used as the standard (hereinafter referred to as the first map). This enables more appropriate control of vehicle travel. The smaller the error in the position of the roads or the features located around the roads shown on the map, or the more accurate the type and presence of the features, the higher the accuracy of the information regarding the roads shown on the map. Therefore, for road sections that have not changed since the first map and the other map (hereinafter referred to as the second map) were last updated, it is preferable that the accuracy of the feature positions and the accuracy of the feature type and presence of the features in that road section are higher in the first map than in the second map. However, the accuracy of the road information on each of the two maps may be the same. Furthermore, in this embodiment, the timing of a map update refers to the timing when information regarding roads shown on the map is updated. For example, if a map server that manages maps or distributes maps to vehicles updates information about a specific road section on a first map to a first date and time, that first date and time becomes the timing for the update.

On the other hand, it is preferable that the second map be updated more frequently than the first map. As a result, even if, for example, some construction work was carried out on a specific road section after the first map was last updated and the first map does not display accurate information about that specific road section, the second map may have been last updated after the construction work on the specific road section was carried out. As a result, the second map may display accurate information about the specific road section. Therefore, the vehicle control device can appropriately control vehicle driving by selectively using the first and second maps depending on the situation.

Figure 1 is a schematic diagram of a vehicle control system in which a vehicle control device is implemented. Figure 2 is a hardware configuration diagram of an electronic control device, which is one embodiment of a vehicle control device. In this embodiment, the vehicle control system 1 is mounted on a vehicle 10 and controls the vehicle 10. The vehicle control system 1 includes a camera 2, a GPS receiver 3, a wireless communication terminal 4, a storage device 5, and an electronic control unit (ECU) 6, which is an example of a vehicle control device. The camera 2, GPS receiver 3, wireless communication terminal 4, storage device 5, and ECU 6 are communicatively connected via an in-vehicle network that conforms to a standard such as a controller area network. The vehicle control system 1 may also include a ranging sensor (not shown), such as a LiDAR or radar, that measures the distance from the vehicle 10 to objects around the vehicle 10. The vehicle control system 1 may also include a navigation device (not shown) that searches for a route to a destination.

Camera 2 is an example of a sensor that generates a sensor signal representing the surroundings of vehicle 10. It has a two-dimensional detector composed of an array of photoelectric conversion elements sensitive to visible light, such as a CCD or C-MOS, and an imaging optical system that forms an image of the area to be photographed on the two-dimensional detector. Camera 2 is mounted, for example, inside the passenger compartment of vehicle 10 so that it faces forward. Camera 2 photographs the area in front of vehicle 10 at a predetermined photographing interval (for example, 1/30 to 1/10 seconds) and generates an image of the area in front of vehicle 10. The image obtained by camera 2 is an example of a sensor signal. Note that vehicle 10 may be equipped with multiple cameras with different photographing directions or focal lengths.

Each time the camera 2 generates an image, it outputs the generated image to the ECU 6 via the in-vehicle network.

The GPS receiver 3 receives GPS signals from GPS satellites at predetermined intervals and determines the vehicle's 10 position based on the received GPS signals. Then, the GPS receiver 3 outputs positioning information representing the results of determining the vehicle's 10 position based on the GPS signals to the ECU 6 via the in-vehicle network at predetermined intervals. Note that instead of a GPS receiver, the vehicle 10 may have a receiver that receives positioning signals from satellites of other satellite positioning systems and determines the vehicle's 10 position.

The wireless communication terminal 4 communicates wirelessly with a wireless base station in accordance with a predetermined mobile communication standard. The wireless communication terminal 4 receives map information representing the first map or the second map, or update information for the first map or the second map, from the map server via the wireless base station. The wireless communication terminal 4 then outputs the received map information or update information to the storage device 5 via the in-vehicle network.

Storage device 5 is an example of a storage unit and includes, for example, a hard disk drive, non-volatile semiconductor memory, or an optical recording medium and its access device. Storage device 5 stores the first map and the second map, as well as update information indicating the date and time when information about each road segment depicted on the first map and the second map was last updated. Note that if the accuracy of the information about roads depicted on the first map differs from the accuracy of the information about roads depicted on the second map, the first map and the second map may each include information indicating the accuracy of the information about the roads (e.g., the average error in the positions of features depicted on the maps).

Furthermore, the storage device 5 has a processor for executing processes such as updating the first or second map and processing related to map read requests from the ECU 6. For example, the storage device 5 transmits a request to acquire the first and second maps, along with the current location of the vehicle 10, to the map server via the wireless communication terminal 4 each time the vehicle 10 travels a predetermined distance. The storage device 5 then receives map information, including the first and second maps, for a predetermined area surrounding the current location of the vehicle 10 from the map server via the wireless communication terminal 4, and stores the first and second maps included in the received map information. Furthermore, when the storage device 5 receives update information for the first or second map via the wireless communication terminal 4, it stores the update information. Furthermore, when the storage device 5 receives a map read request from the ECU 6, it extracts an area from the stored first and second maps that includes the current location of the vehicle 10 and is relatively narrower than the predetermined area, and outputs the extracted area to the ECU 6 via the in-vehicle network.

The ECU 6 controls the automatic driving of the vehicle 10 based on the first map or the second map.

As shown in FIG. 2, the ECU 6 has a communication interface 21, a memory 22, and a processor 23. The communication interface 21, the memory 22, and the processor 23 may each be configured as separate circuits, or may be integrated into a single integrated circuit.

The communication interface 21 has an interface circuit for connecting the ECU 6 to the in-vehicle network. Each time the communication interface 21 receives an image from the camera 2, it passes the received image to the processor 23. Each time the communication interface 21 receives positioning information from the GPS receiver 3, it passes the positioning information to the processor 23. Furthermore, the communication interface 21 passes the first and second maps and update information read from the storage device 5 to the processor 23.

Memory 22 is another example of a storage unit and includes, for example, volatile and non-volatile semiconductor memory. Memory 22 stores various data used in the vehicle control process executed by processor 23. For example, memory 22 stores images of the surroundings of vehicle 10 received from camera 2, positioning information of vehicle 10 received from GPS receiver 3, and first and second maps and update information read from storage device 5. Memory 22 also stores parameters such as the focal length, shooting direction, and mounting position of camera 2, as well as various parameters for identifying object detection classifiers used to detect features, etc. Memory 22 also temporarily stores various data generated during the vehicle control process.

The processor 23 has one or more CPUs (Central Processing Units) and their peripheral circuits. The processor 23 may also have other arithmetic circuits such as a logic operation unit, a numerical operation unit, or a graphics processing unit. The processor 23 then executes vehicle control processing for the vehicle 10 at predetermined intervals.

Figure 3 is a functional block diagram of the processor 23 related to vehicle control processing. The processor 23 has a switching point detection unit 31, a detection unit 32, a driving lane determination unit 33, and a control unit 34. Each of these units in the processor 23 is a functional module realized by, for example, a computer program running on the processor 23. Alternatively, each of these units in the processor 23 may be a dedicated arithmetic circuit provided in the processor 23.

The switching point detection unit 31 detects a switching point where the map used for driving control of the vehicle 10 switches from one of the first and second maps to the other within a section from the current position of the vehicle 10 to a predetermined distance ahead in the direction of travel of the vehicle 10.

To this end, the switching point detection unit 31 determines the position of the vehicle 10 indicated by the most recent positioning information as the current position of the vehicle 10. The switching point detection unit 31 also determines the direction of travel of the vehicle 10 based on changes in the position of the vehicle 10 indicated by the most recent multiple pieces of positioning information, or based on a sensor signal indicating the orientation of the vehicle 10 received by the ECU 6 from a direction sensor (not shown) mounted on the vehicle 10. Furthermore, the switching point detection unit 31 references either the first map or the second map, whichever is currently being used to control the travel of the vehicle 10, and determines the road including the current position of the vehicle 10 as the road on which the vehicle 10 is traveling.

The switching point detection unit 31 refers to update information for a section of the road on which the vehicle 10 is traveling, up to a predetermined distance from the vehicle 10's current position, and compares the timing of the last update for the first map and the second map. It then determines whether there is a section of the first map or the second map where the update timing of the map used to control the vehicle 10's travel at the vehicle's current position is later than the update timing of the other map. If such a section is found, the switching point detection unit 31 detects the start point, which is the endpoint of that section closer to the vehicle 10, as the switching point.

Alternatively, the switching point detection unit 31 determines whether there is an unsupported section of the road on which the vehicle 10 is traveling, within a section from the current position of the vehicle 10 to a predetermined distance away, that is not shown on either the first map or the second map, whichever map is being used to control the vehicle 10's travel at the vehicle's current position. Furthermore, if the unsupported section is shown on the other map, the switching point detection unit 31 detects the start point, which is the endpoint of the unsupported section closest to the vehicle 10, as the switching point.

Alternatively, the switching point detection unit 31 determines whether there is a deviation section within a predetermined distance from the current position of the vehicle 10, where the information displayed on the first map and the information displayed on the second map diverge. If there is a deviation section, the switching point detection unit 31 may detect, as switching points, the start point, which is the endpoint of the deviation section closer to the vehicle 10, and the end point, which is the endpoint farthest from the vehicle 10. However, if the first map and the second map are the same, and the map with the shorter elapsed time since the information about the deviation section was updated is the same as the map with the shorter elapsed time since the information about the sections before and after the deviation section was updated, the switching point detection unit 31 does not need to set the endpoints of the deviation section as switching points. This is because, for both the deviation section and the sections before and after the deviation section, the map with the shorter elapsed time since the information was updated is more likely to represent more accurate information than the other map.

To detect deviation sections, the switching point detection unit 31 sets sampling points at first intervals (e.g., several hundred meters to 1 km) along a section extending a predetermined distance from the current position of the vehicle 10 in the direction of travel of the vehicle 10. The switching point detection unit 31 then calculates, for each sampling point, the distance between the position of the road on which the vehicle 10 is traveling or a feature around it (e.g., lane markings, curbs, guardrails, or road signs) shown on the first map at that sampling point and the position of the corresponding feature shown on the second map, as the deviation. Note that when features that are continuous along the road, such as the lane markings in the above example, are used to calculate the deviation, the switching point detection unit 31 may calculate, as the deviation, the distance from the position of the feature shown on the first map at the sampling point of interest to the closest position of the corresponding feature shown on the second map. The switching point detection unit 31 may also calculate the deviation as the average value of the distance between the position of each of the multiple features shown on the first map at the sampling point of interest and the position of the corresponding feature shown on the second map.

The switching point detection unit 31 compares the deviation calculated for each sampling point with a predetermined threshold. The switching point detection unit 31 then identifies sampling points where the deviation is equal to or greater than the predetermined threshold. The switching point detection unit 31 resets sampling points at second intervals (e.g., several tens to 100 meters) that are narrower than the first intervals before and after each sampling point where the deviation is equal to or greater than the predetermined threshold. The switching point detection unit 31 then calculates the deviation between the first map and the second map for each reset sampling point, as described above. The switching point detection unit 31 then identifies sampling points from the reset sampling points where the deviation is equal to or greater than the predetermined threshold. The switching point detection unit 31 then detects, as a deviation section, the section from the sampling point immediately before the sampling point closest to the vehicle 10, among the sampling points where the deviation degree is equal to or greater than the predetermined threshold, to the sampling point immediately after the sampling point farthest from the vehicle 10, among the sampling points where the deviation degree is equal to or greater than the predetermined threshold.

The switching point detection unit 31 may set a deviation degree equal to or greater than a predetermined threshold for sampling points where the number of lanes or the number of lane markings differ between the first and second maps. The switching point detection unit 31 may also set a deviation degree equal to or greater than a predetermined threshold for sampling points where the type of lane markings differ between the first and second maps. Furthermore, the switching point detection unit 31 may set points where the presence or absence of predetermined features, such as road signs or guardrails, differ between the first and second maps as sampling points with a deviation degree equal to or greater than a predetermined threshold.

The switching point detection unit 31 notifies the control unit 34 of the detected switching point.

The detection unit 32 detects other vehicles traveling around the vehicle 10. For ease of explanation, other vehicles traveling around the vehicle 10 will be referred to as surrounding vehicles below. The detection unit 32 then estimates the distance between the detected surrounding vehicles and the vehicle 10, as well as the direction from the vehicle 10 to the surrounding vehicles.

The detection unit 32 detects one or more surrounding vehicles and identifies the vehicle type (e.g., passenger car, large vehicle, motorcycle, etc.) of each detected surrounding vehicle by, for example, inputting images obtained by the camera 2 or ranging signals obtained by a ranging sensor (not shown) into a classifier pre-trained to detect surrounding vehicles. The detection unit 32 may use a deep neural network (DNN) with a convolutional neural network (CNN)-type architecture, such as the Single Shot MultiBox Detector or Faster R-CNN, as such a classifier. Alternatively, the detection unit 32 may use a DNN with a self-attention network (SAN)-type architecture, such as the Vision Transformer, as such a classifier. Alternatively, the detection unit 32 may use a classifier based on other machine learning techniques, such as the AdaBoost classifier, as such a classifier. Such a classifier is pre-trained according to a predetermined learning method, such as backpropagation, using a large number of training images depicting vehicles, so as to detect surrounding vehicles from images. The classifier outputs information identifying the object region containing the surrounding vehicle detected on the input image and information indicating the type of the detected surrounding vehicle.

The detection unit 32 further estimates the distance between the vehicle 10 and each of the detected surrounding vehicles, and determines the direction from the vehicle 10 to the surrounding vehicle. Note that the detection unit 32 only needs to perform the same processing for each surrounding vehicle, so the following describes the processing for one surrounding vehicle.

Here, the position of the bottom edge of the object area including the surrounding vehicle is assumed to represent the position where the surrounding vehicle touches the road surface. Furthermore, positions on the image have a one-to-one correspondence with the orientation as seen from the camera that generated the image. Therefore, the detection unit 32 can estimate the distance from camera 2 to the surrounding vehicle and the orientation from vehicle 10 to the surrounding vehicle by referencing the position of the bottom edge of the object area on the image and parameters such as the installation height and shooting direction of camera 2. Alternatively, the detection unit 32 may estimate the distance from camera 2 to the surrounding vehicle based on the reference number of pixels on the image when the inter-vehicle distance is the reference distance, which corresponds to the reference vehicle width corresponding to the vehicle type of the surrounding vehicle, and the horizontal width of the object area including the surrounding vehicle. The detection unit 32 may then determine the distance from camera 2 to the surrounding vehicle as the distance between vehicle 10 and the surrounding vehicle.

Furthermore, when a surrounding vehicle is detected based on the ranging signal, the detection unit 32 may determine the direction in which the surrounding vehicle was detected on the ranging signal as the direction from the vehicle 10 to the surrounding vehicle. Furthermore, the detection unit 32 may determine the distance indicated in the ranging signal for that direction as the estimated distance from the vehicle 10 to the surrounding vehicle.

For each detected nearby vehicle, the detection unit 32 notifies the driving lane determination unit 33 and the control unit 34 of information indicating the vehicle type of the nearby vehicle, the estimated distance between the vehicle 10 and the nearby vehicle, and the direction from the vehicle 10 to the nearby vehicle.

The driving lane determination unit 33 determines the lane in which each nearby vehicle detected by the detection unit 32 is traveling.

In this embodiment, the driving lane determination unit 33 determines whether a nearby vehicle (hereinafter referred to as a preceding vehicle) traveling ahead of vehicle 10 among the detected surrounding vehicles is traveling in the lane in which vehicle 10 is traveling (hereinafter referred to as the vehicle's own lane). To do this, the driving lane determination unit 33 identifies, among the surrounding vehicles, a nearby vehicle whose orientation from vehicle 10 is within a predetermined angle range (e.g., ±60° to ±80°) centered on the vehicle's direction of travel as the preceding vehicle. Furthermore, the driving lane determination unit 33 determines whether the preceding vehicle is traveling in the vehicle's own lane by referring to one of the first and second maps, which is used to control vehicle 10's travel at the vehicle's current location. In other words, until vehicle 10 reaches the switching point, the driving lane determination unit 33 refers to the map that was previously used to control vehicle 10's travel. On the other hand, once vehicle 10 passes the switching point, driving lane determination unit 33 refers to a map different from the map previously used to control vehicle 10's travel. Note that driving lane determination unit 33 sets the most recent position of vehicle 10 measured by GPS receiver 3 as the current position of vehicle 10. Alternatively, driving lane determination unit 33 may determine the current position of vehicle 10 by correcting the most recent position of vehicle 10 measured by GPS receiver 3 using odometry information from the time of that positioning to the present time. Then, driving lane determination unit 33 may determine whether vehicle 10 has reached the switching point by comparing the current position of vehicle 10 with the switching point.

Furthermore, the driving lane determination unit 33 estimates the position of the preceding vehicle based on a more accurate position of vehicle 10, the estimated distance between vehicle 10 and the preceding vehicle, and the direction from vehicle 10 to the preceding vehicle. Then, the driving lane determination unit 33 determines, in a map referenced in controlling the driving of vehicle 10, the lane containing the estimated position of the preceding vehicle as the lane in which the preceding vehicle is traveling. Furthermore, in a map referenced in controlling the driving of vehicle 10, the driving lane determination unit 33 determines whether the lane in which the preceding vehicle is traveling is the same as the own lane. If the lane in which the preceding vehicle is traveling is the same as the own lane, the driving lane determination unit 33 determines that the preceding vehicle is traveling in the own lane. On the other hand, if the lane in which the preceding vehicle is traveling is different from the own lane, the driving lane determination unit 33 determines that the preceding vehicle is not traveling in the own lane.

To detect the exact position of the vehicle 10, the driving lane determination unit 33 compares the image generated by the camera 2 with the map used for driving control. For example, the driving lane determination unit 33 assumes the position and attitude of the vehicle 10 and projects onto the map features on or around the road detected from the image, or projects onto the image features on or around the road around the vehicle 10 shown on the map. Note that features on or around the road may be, for example, road markings such as lane markings or stop lines, or curbs. The driving lane determination unit 33 then estimates the position and attitude of the vehicle 10 when the features detected from the image most closely match the features shown on the map as the vehicle's 10's exact position. Furthermore, the driving lane determination unit 33 detects the lane on the map that includes the vehicle's current position as the vehicle's current lane.

The driving lane determination unit 33 determines the position where features will be projected on the map or image using the assumed initial values of the position and attitude of the vehicle 10 and parameters of the camera 2, such as focal length, installation height, and shooting direction. The initial values of the position and attitude of the vehicle 10 are the latest position of the vehicle 10 measured by the GPS receiver 3, or the position and attitude of the vehicle 10 estimated during the previous self-position detection, corrected using odometry information. The driving lane determination unit 33 then calculates the degree of match between features on or around the road detected from the image and corresponding features shown on the map (for example, the inverse of the sum of the squares of the distances between corresponding features).

The driving lane determination unit 33 repeats the above process while changing the assumed position and attitude of the vehicle 10. The driving lane determination unit 33 then estimates the assumed position and attitude when the degree of match is greatest as the accurate own position of the vehicle 10. The driving lane determination unit 33 then refers to the map used for driving control and identifies the lane that includes the own position of the vehicle 10 as the own lane.

The driving lane determination unit 33 may detect the feature to be detected by, for example, inputting the image into a classifier that has been trained in advance to detect the feature from the image. The driving lane determination unit 33 may use, as such a classifier, a classifier similar to the classifier used by the detection unit 32 to detect surrounding vehicles. Alternatively, the classifier used by the detection unit 32 may detect not only surrounding vehicles but also the feature to be detected.

Furthermore, the driving lane determination unit 33 determines whether not only the preceding vehicle but also other surrounding vehicles are traveling in lanes adjacent to the own lane (hereinafter referred to as adjacent lanes). In this case, the driving lane determination unit 33 may determine the lane in which the surrounding vehicles are traveling using a process similar to the process for determining the lane in which the preceding vehicle is traveling described above. The driving lane determination unit 33 then determines that the surrounding vehicles are traveling in an adjacent lane if the lane in which the surrounding vehicles are traveling is adjacent to the own lane on a map referenced in controlling the traveling of the vehicle 10. Alternatively, the driving lane determination unit 33 may determine the lateral distance between the vehicle 10 and the surrounding vehicles in a direction perpendicular to the traveling direction of the vehicle 10 based on the estimated distance between the vehicle 10 and the surrounding vehicles and the direction from the vehicle 10 to the surrounding vehicles. The driving lane determination unit 33 may then determine that the surrounding vehicles are traveling in an adjacent lane if the lateral distance is within a distance range equivalent to the width of one lane.

The driving lane determination unit 33 notifies the control unit 34 of the determination result of the lane in which each surrounding vehicle, including the preceding vehicle, is traveling.

The control unit 34 controls the driving of the vehicle 10 by referring to the map, either the first or second map, that is used to control the driving of the vehicle 10. In this embodiment, as described in the driving lane determination unit 33, the control unit 34 uses, for driving control, either the first map or the second map, whichever map has been used up until that point. On the other hand, once the vehicle passes the switching point, the control unit 34 uses, for driving control, either the first map or the second map, whichever map is different from the map that has been used up until that point. More specifically, if the switching point is set based on the difference between the last update timing of the first map and the last update timing of the second map, the control unit 34 uses, for driving control, the map, either the first map or the second map, which has been updated later, for the section before the switching point and the section after the switching point, respectively. Furthermore, when a switching point is set based on the presence or absence of an unsupported section, the control unit 34 uses, for driving control, the map from the first map or the second map that displays information about the section before the switching point and the section after the switching point. Furthermore, when a switching point is set based on the presence or absence of a deviation section, the control unit 34 uses, for driving control, the map from the first map or the second map that has more accurate road information for sections other than the deviation section. For deviation sections, the control unit 34 uses, for driving control, the map from the first map or the second map that is updated more frequently or that has been updated less recently.

For example, the control unit 34 controls each part of the vehicle 10 so that the vehicle 10 continues traveling in the current lane. In doing so, the control unit 34 sets the acceleration/deceleration of the vehicle 10 so that the inter-vehicle distance between the vehicle 10 and a preceding vehicle traveling in the current lane is maintained at a predetermined distance or greater.

Here, if the information about roads displayed on the first map differs from the information about roads displayed on the second map for the section after the switching point, the results of determining the positional relationship between surrounding vehicles and vehicle 10, or the predicted behavior of the surrounding vehicles, may suddenly change before and after the map used for cruise control switches at the switching point. Due to such changes, control unit 34 may need to change the driving behavior of vehicle 10 when vehicle 10 passes through the switching point. For example, control unit 34 may need to decelerate or accelerate vehicle 10, or change the position of vehicle 10 within the own lane in a direction perpendicular to the extension of the own lane (hereinafter referred to as the width direction or lateral direction). Even in such cases, control unit 34 controls acceleration/deceleration so that the absolute value of the change in acceleration/deceleration per unit time is equal to or less than a predetermined threshold.

First, we will explain an example in which it becomes necessary to change the driving behavior of vehicle 10 because the results of determining the positional relationship between vehicle 10 and surrounding vehicles change before and after the map used for driving control is switched.

Figure 4 shows an example in which the determination result of the positional relationship between the preceding vehicle and vehicle 10 changes before and after the map used for cruise control is switched. In this example, a first map is used for cruise control until vehicle 10 reaches switching point Pc, and a second map is used for cruise control after vehicle 10 passes switching point Pc. Also, in Figure 4, the lane 400 in which vehicle 10 is traveling is represented by a solid line. In contrast, in the first map, the lane 400 is represented by a dashed line 401, and in the second map, the lane 400 is represented by a dashed line 402.

As shown, in the section beyond the switching point Pc, the actual vehicle lane 400 curves to the right in the direction of travel of the vehicle 10. The second map also depicts the vehicle lane 400 in this manner, whereas the first map depicts it as a straight line. Therefore, the first map is referenced until the vehicle 10 reaches the switching point Pc, and even if the preceding vehicle 410 of the vehicle 10 is traveling on the curved section of the vehicle lane 400, it is determined that the preceding vehicle 410 is not traveling in the vehicle lane. Therefore, the control unit 34 controls the traveling of the vehicle 10 regardless of the inter-vehicle distance d between the vehicle 10 and the preceding vehicle 410. However, once the vehicle 10 passes the switching point Pc, the referenced map is switched from the first map to the second map. Therefore, the determination result by the traveling lane determination unit 33 changes from a determination that the preceding vehicle 410 is traveling outside the vehicle lane to a determination that the preceding vehicle 410 is traveling in the vehicle lane. As a result, the control unit 34 needs to set the acceleration/deceleration rate according to the inter-vehicle distance d between the vehicle 10 and the preceding vehicle 410. In particular, if the inter-vehicle distance d is less than a predetermined distance, the control unit 34 decelerates the vehicle 10 so that the inter-vehicle distance d increases.

As described above, if the vehicle 10 needs to decelerate due to a change in the map used for cruise control, the driver may feel uneasy if the vehicle 10 suddenly decelerates. Therefore, the control unit 34 decelerates the vehicle 10 if, before and after the map used for cruise control is changed, the determination result of the lane in which the preceding vehicle is traveling changes from a result indicating that the preceding vehicle is traveling in a lane other than the vehicle's own lane to a result indicating that the preceding vehicle is traveling in the vehicle's own lane, and if, after the map change, the inter-vehicle distance between the preceding vehicle and vehicle 10 is less than a predetermined distance. In this case, the control unit 34 suppresses the absolute value of the change in deceleration per unit time to a predetermined threshold or less. This prevents the vehicle 10 from suddenly decelerating before and after the map change used for cruise control, thereby reducing the driver's sense of uneasiness.

Figure 5 shows an example of the relationship between the change in inter-vehicle distance between vehicle 10 and the preceding vehicle and the change in acceleration/deceleration of vehicle 10 over time for the example shown in Figure 4. The horizontal axis of each of the upper and lower charts in Figure 5 represents time. The vertical axis of the upper chart represents inter-vehicle distance, and the vertical axis of the lower chart represents acceleration/deceleration of vehicle 10. Furthermore, the upper chart 501 represents the change in inter-vehicle distance between vehicle 10 and the preceding vehicle over time, and the lower chart 502 represents the change in acceleration/deceleration of vehicle 10 over time. However, if the acceleration/deceleration is a positive value, it indicates that vehicle 10 is accelerating, and if the acceleration/deceleration is a negative value, it indicates that vehicle 10 is decelerating. Then, at time t1, vehicle 10 passes through switching point Pc, and the maps used for cruise control are switched before and after that.

As shown in chart 501, until time t1, the first map determines that the preceding vehicle is not traveling in the vehicle's own lane, so the inter-vehicle distance is represented by a dashed line. Therefore, even if the inter-vehicle distance is less than the predetermined distance Thd, vehicle 10 does not decelerate. However, at time t1, the map used for cruise control switches from the first map to the second map, and it is determined that the preceding vehicle is traveling in the vehicle's own lane. Therefore, from time t1 onward, the inter-vehicle distance is represented by a solid line. Since the inter-vehicle distance is less than the predetermined distance Thd at time t1, as shown in chart 502, from time t1 onward, the control unit 34 decelerates vehicle 10 so that the deceleration gradually increases. At this time, the amount of change in deceleration per unit time, i.e., the absolute value of the slope α of chart 502, is kept below a predetermined threshold value Th. Once the deceleration reaches the predetermined deceleration, the control unit 34 maintains the deceleration constant until the inter-vehicle distance increases to a certain extent. The control unit 34 then gradually reduces the deceleration, and when the inter-vehicle distance becomes equal to or greater than the predetermined distance Thd, the deceleration is set to 0. In this way, even if the determination result of the driving lane of the preceding vehicle changes when the map used for cruise control is switched, the control unit 34 does not suddenly decelerate the vehicle 10. As a result, the control unit 34 does not cause the driver to feel uneasy.

Next, we will explain an example in which it becomes necessary to change the driving behavior of vehicle 10 because the predicted behavior of surrounding vehicles changes before and after the map used for driving control is switched.

Figure 6 shows an example in which the predicted behavior of surrounding vehicles changes before and after the map used for cruise control is switched. In this example, the first map is used for cruise control until the vehicle 10 reaches the switching point Pc, and the second map is used for cruise control after the vehicle 10 passes the switching point Pc. Also, in Figure 6, the current lane 600 and adjacent lane 601 in which the vehicle 10 is traveling are represented by solid lines. In contrast, the current lane 600 and adjacent lane 601 are represented by dashed lines 610 in the first map, and the current lane 600 and adjacent lane 601 are represented by dashed lines 611 in the second map.

As shown in the figure, in the section beyond the switching point Pc, the first map shows the adjacent lane 601 merging into the own lane 600. In this case, the first map is referenced until the vehicle 10 reaches the switching point Pc, and the control unit 34 predicts that the surrounding vehicle 620 traveling ahead of the vehicle 10 in the adjacent lane 601 will change lanes into the own lane 600. As a result, when the surrounding vehicle 620 changes lanes into the own lane 600, the control unit 34 suppresses the speed of the vehicle 10 so that the inter-vehicle distance between the vehicle 10 and the surrounding vehicle 620 is equal to or greater than a predetermined distance.

However, in reality, adjacent lane 601 does not merge into the current lane 600, and the current lane 600 and adjacent lane 601 continue straight while remaining adjacent to each other. The second map also shows adjacent lane 601 and adjacent lane 600 continuing straight while remaining adjacent to each other. Therefore, when vehicle 10 passes through switching point Pc and the referenced map switches from the first map to the second map, control unit 34 predicts that nearby vehicle 620 traveling in adjacent lane 601 will continue straight. As a result, control unit 34 no longer needs to suppress the speed of vehicle 10, and instead accelerates vehicle 10 to the target vehicle speed.

In this way, if the vehicle 10 needs to accelerate due to a change in the map used for cruise control, the driver may feel uncomfortable if the vehicle 10 suddenly accelerates. Therefore, if the presence or absence of a merging point shown on the map changes before and after the map used for cruise control is changed and the vehicle 10 is decelerating, the control unit 34 accelerates the vehicle 10 after the map is changed. At that time, the control unit 34 suppresses the absolute value of the change in acceleration per unit time to below a predetermined threshold. This prevents the vehicle 10 from suddenly accelerating before and after the map used for cruise control is changed, reducing discomfort to the driver.

Figure 7 shows an example of the relationship between the presence or absence of a merging point shown on the map used for cruise control and the change in acceleration/deceleration of the vehicle 10 over time for the example shown in Figure 6. The horizontal axis of each of the upper and lower charts in Figure 7 represents time. The vertical axis of the upper chart represents the presence or absence of a merging point, and the vertical axis of the lower chart represents the acceleration/deceleration of the vehicle 10. Furthermore, the upper chart 701 represents the change in the presence or absence of a merging point shown on the map used for cruise control over time, and the lower chart 702 represents the change in acceleration/deceleration of the vehicle 10 over time. However, if the acceleration/deceleration is a positive value, it indicates that the vehicle 10 is accelerating, and if the acceleration/deceleration is a negative value, it indicates that the vehicle 10 is decelerating. Then, at time t1, the vehicle 10 passes through the switching point Pc, and the map used for cruise control is switched before and after that.

As shown in chart 701, the first map is referenced until time t1, and it is determined that there is a merging point ahead of vehicle 10. However, when the map used for cruise control switches from the first map to the second map at time t1, the merging point is no longer displayed on the second map, and it is determined that there is no merging point ahead of vehicle 10. Therefore, as shown in chart 702, before time t1, it is predicted that a nearby vehicle traveling in an adjacent lane will change lanes into the vehicle's own lane ahead of vehicle 10, and vehicle 10 decelerates. However, after time t1, it is predicted that the nearby vehicle will continue traveling straight in the adjacent lane, and therefore, from time t1 onwards, the control unit 34 accelerates vehicle 10 so that the acceleration gradually increases. At this time, the change in acceleration per unit time, i.e., the absolute value of the slope α of chart 702, is suppressed to a predetermined threshold value Th or less. Once the acceleration reaches the predetermined acceleration, the control unit 34 maintains the acceleration constant until the speed of the vehicle 10 approaches the target vehicle speed. The control unit 34 then gradually reduces the acceleration, and when the speed of the vehicle 10 reaches the target vehicle speed, the acceleration is set to zero. In this way, even if the predicted behavior of a nearby vehicle traveling in an adjacent lane changes when the map used for cruise control is switched, the control unit 34 does not suddenly accelerate the vehicle 10. As a result, the control unit 34 can reduce discomfort to the driver.

Once the acceleration/deceleration is set as described above, the control unit 34 sets the accelerator opening or braking amount according to the set acceleration/deceleration. The control unit 34 calculates the fuel injection amount according to the set accelerator opening, and outputs a control signal corresponding to the fuel injection amount to the fuel injection device of the engine of the vehicle 10. Alternatively, the control unit 34 calculates the amount of power to be supplied to the motor according to the set accelerator opening, and controls the motor drive circuit so that the amount of power is supplied to the motor. Alternatively, the control unit 34 outputs a control signal corresponding to the set braking amount to the brake of the vehicle 10.

In addition, when causing the vehicle 10 to continue traveling in the current lane, the control unit 34 creates a planned driving route that passes through the current lane and controls each part of the vehicle 10 so that the vehicle 10 travels along the planned driving route. In doing so, the control unit 34 creates the planned driving route by referencing a map used for driving control. For example, the control unit 34 creates a planned driving route that passes through the center between the two lane markings that divide the current lane, as shown on the map.

If the accuracy of the road information shown on the map used for cruise control for the section before the switching point differs from the accuracy of the road information shown on the map used for cruise control for the section after the switching point, the position of the lane markings in the lateral direction may change before and after the switching point. In such a case, the lateral position of the planned driving route also changes before and after the switching point.

Figure 8 is a diagram showing an example in which the position of lane markings shown on a map changes before and after the map used for cruise control is switched. In this example, the first map is used for cruise control until the vehicle 10 reaches the switching point Pc, and the second map is used for cruise control after the vehicle 10 passes the switching point Pc. Also, in Figure 8, the lane markings 800 that define the lane in which the vehicle 10 is traveling are represented by solid lines. In contrast, the lane markings 800 on the first map are represented by dashed lines 801, and the lane markings 800 on the second map are represented by dashed lines 802.

As shown in the figure, the lateral position of lane marking 802 shown on the second map is offset from the lateral position of lane marking 801 shown on the first map. As a result, the lateral position of planned driving route 810 created based on the lane markings also shifts before and after switching point Pc. Because vehicle 10 cannot move sideways suddenly, control unit 34 creates planned driving route 810 so that planned driving route 810 smoothly connects before and after switching point Pc. Even so, if vehicle 10 is traveling along planned driving route 810 in the section just before switching point Pc, the position of vehicle 10 will shift from planned driving route 810 after vehicle 10 passes switching point Pc.

The control unit 34 therefore controls the vehicle 10 so that the vehicle 10 approaches the planned driving route 810. The control unit 34 measures the position of the vehicle 10 at predetermined intervals and compares the measured position of the vehicle 10 with the planned driving route. As explained for the driving lane determination unit 33, the control unit 34 can measure the exact position of the vehicle 10 by comparing the image obtained by the camera 2 with the map used to generate the planned driving route.

The control unit 34 may measure the position of the vehicle 10 without using a map. In particular, when the map containing less accurate road information is used for driving control, between the first and second maps, the control unit 34 may estimate the position of the vehicle 10 without using a map. By estimating the position of the vehicle 10 without using a map in this manner, the control unit 34 can suppress a decrease in the accuracy of estimating the position of the vehicle 10 due to the accuracy of the information displayed on the map. In this case, the control unit 34 inputs the image obtained by the camera 2 into a classifier to detect the left and right lane markings that demarcate the vehicle's lane displayed in the image. The control unit 34 then estimates the positions of the left and right lane markings relative to the camera 2 based on the horizontal positions of the left and right lane markings closest to the bottom of the image and parameters such as the focal length, shooting direction, and installation height of the camera 2. Furthermore, the control unit 34 may measure the lateral position of the vehicle 10 within the vehicle's lane based on the estimation results.

If the measured position of vehicle 10 is on the planned driving route, control unit 34 determines the steering angle of vehicle 10 so that vehicle 10 moves along the planned driving route, and controls the steering of vehicle 10 to achieve the determined steering angle. Also, if the measured position of vehicle 10 is away from the planned driving route, control unit 34 determines the steering angle of vehicle 10 so that vehicle 10 moves closer to the planned driving route, and controls the steering of vehicle 10 to achieve the determined steering angle.

At that time, the control unit 34 controls the vehicle 10 so that the absolute value of the change in lateral acceleration per unit time is equal to or less than a predetermined threshold. For example, the control unit 34 adjusts the steering angle so that the absolute value of the change in lateral acceleration per unit time is equal to or less than a predetermined threshold. A reference table representing the relationship between the speed of the vehicle 10 and the change in steering angle per unit time at which the absolute value of the change in lateral acceleration per unit time is equal to or less than the predetermined threshold is stored in the memory 22 in advance. The control unit 34 determines the change in steering angle per unit time by referencing the speed of the vehicle 10 measured by a vehicle speed sensor (not shown) and the reference table. This prevents the vehicle 10 from suddenly moving laterally before and after switching maps used for cruise control, reducing anxiety felt by the driver.

Figure 9 shows an example of the relationship between the lateral position of the planned driving route and the change over time in the lateral acceleration/deceleration of the vehicle 10 for the example shown in Figure 8. The horizontal axis of each of the upper and lower charts in Figure 9 represents time. The vertical axis of the upper chart represents the lateral position, and the vertical axis of the lower chart represents the lateral acceleration of the vehicle 10. Furthermore, the upper chart 901 represents the change over time in the lateral position of the planned driving route, and the lower chart 902 represents the change over time in the lateral acceleration of the vehicle 10. Then, at time t1, the vehicle 10 passes through the switching point Pc, and the maps used for driving control are switched before and after that.

As shown in chart 901, around time t1, the map used for driving control switches from the first map to the second map, causing a change in the lateral position of the planned driving route. Therefore, after time t1, the control unit 34 controls the vehicle 10 so that it approaches the planned driving route. At this time, as shown in chart 902, the control unit 34 gradually increases the steering angle so that the amount of change in lateral acceleration per unit time, i.e., the absolute value of the slope β of chart 902, is kept below a predetermined threshold Th. Once the lateral acceleration reaches a predetermined acceleration, the control unit 34 maintains the steering angle constant to maintain the lateral acceleration constant until the difference between the lateral position of the vehicle 10 and the planned driving route becomes less than a certain level. The control unit 34 then reduces the steering angle so that the lateral acceleration gradually decreases. Once the vehicle 10 is aligned with the planned driving route, the control unit 34 controls the steering angle so that the lateral acceleration becomes zero. In this way, when the map used for cruise control is switched, even if the lateral position of the lane markings shown on that map changes, the control unit 34 does not cause the vehicle 10 to suddenly move laterally. As a result, the control unit 34 does not cause the driver to feel uneasy.

Figure 10 is an operational flowchart of the vehicle control process that accompanies switching of maps used for driving control.

The control unit 34 of the processor 23 determines whether to switch the map used for driving control (step S101). As described above, the control unit 34 may determine that the map used for driving control should be switched when the vehicle 10 passes the switching point.

If the map used for driving control is not to be switched (step S101—No), the control unit 34 controls the driving of the vehicle 10 by referring to the map that was previously used, either the first map or the second map (step S102). On the other hand, if the map used for driving control is to be switched (step S101—Yes), the control unit 34 will thereafter use the map that is different from the map that was previously used, either the first map or the second map. The control unit 34 then determines whether or not it is necessary to change the driving behavior of the vehicle 10 in response to the map switch (step S103).

If there is no need to change the behavior of the vehicle 10 (step S103—No), the control unit 34 controls the vehicle 10 to maintain its previous driving behavior (step S104). On the other hand, if there is a need to change the behavior of the vehicle 10 (step S103—Yes), the control unit 34 controls the vehicle 10 to transition to the driving behavior required after switching maps, while suppressing the amount of change in acceleration/deceleration per unit time to a predetermined threshold or less (step S105). After step S102, S104, or S105, the processor 23 terminates the vehicle control process.

As explained above, when the map used to control the vehicle's driving is switched from one map to another, this vehicle control device controls the acceleration/deceleration so that the absolute value of the change in the vehicle's acceleration/deceleration per unit time required to transition from the vehicle's driving behavior based on one map to the vehicle's driving behavior based on the other map is below a predetermined threshold. Therefore, this vehicle control device can prevent the driver from feeling uneasy or uncomfortable when the map used to control the vehicle's driving is switched.

According to a modified example, when the vehicle 10 and a nearby vehicle traveling in an adjacent lane are traveling side by side, the control unit 34 may execute a Vehicle Lateral Offset (VLO) function. That is, when a nearby vehicle is determined to be traveling in the adjacent lane and its estimated distance from the vehicle 10 is within a predetermined distance, the control unit 34 may shift the planned driving path away from the adjacent lane by a predetermined offset amount from the center of the vehicle's own lane so as to increase the lateral distance between the vehicle 10 and the nearby vehicle. In this case, if the accuracy of the road information displayed on the map used for driving control is low, the distance between the planned driving path and the actual lane markings may become too short. As a result, the vehicle 10 may get too close to the lane markings. Therefore, if the accuracy of the road information differs between the first map and the second map, the control unit 34 may change the predetermined offset amount depending on the map used for driving control. For example, if the accuracy of the road information displayed on the second map is lower than the accuracy of the information displayed on the first map, the control unit 34 reduces the predetermined offset amount when the second map is used for driving control compared to the predetermined offset amount when the first map is used for driving control.

Figures 11(a) and 11(b) are diagrams showing the relationship between the maps used for cruise control and the offset amount in the VLO function. In Figures 11(a) and 11(b), the lane markings 1101 that separate the vehicle's lane 10 and adjacent lanes are represented by solid lines. Furthermore, in the first map, the lane markings 1102 that separate the vehicle's lane and adjacent lanes are represented by dashed lines, and in the second map, the lane markings 1103 that separate the vehicle's lane and adjacent lanes are represented by dashed lines. Furthermore, in this example, the accuracy of the information about roads represented on the first map is assumed to be higher than the accuracy of the information about roads represented on the second map.

Figure 11(a) shows the offset amount Δ1 when the first map, which has relatively high accuracy of road-related information, is used for driving control. In this example, the position of the actual lane marking 1101 and the position of the lane marking 1102 shown on the first map are nearly identical. Therefore, the offset amount Δ1 for increasing the distance between vehicle 10 and a nearby vehicle 1110 traveling in an adjacent lane is also set to be relatively large.

Figure 11(b) shows the offset amount Δ2 when the second map, which has relatively low-accuracy road-related information, is used for cruise control. In this example, the position of the lane marking 1103 shown on the second map is shifted on the opposite side of the adjacent lane in which the surrounding vehicle 1110 is traveling, relative to the actual position of the lane marking 1101. Therefore, if the planned cruise path is shifted from the center of the own lane calculated based on the lane marking 1103 shown on the second map by the offset amount Δ1 used when the first map is used for cruise control, the vehicle 10 will get too close to the actual lane marking 1101. Therefore, the specified offset amount Δ2 when the second map is used for cruise control is set to a value smaller than Δ1. This prevents the vehicle 10 from getting too close to the lane marking.

Figure 12 is an operational flowchart of the vehicle control process related to the VLO function according to this modified example. When the control unit 34 determines that the VLO function should be executed, it controls the vehicle 10 according to the following operational flowchart.

The control unit 34 determines whether the map currently being used for cruise control, out of the first map and the second map, is the map with the higher accuracy of road information (step S201). If the map currently being used for cruise control is the map with the higher accuracy of road information (step S201—Yes), the control unit 34 sets the predetermined offset amount to a relatively large value (step S202). On the other hand, if the map currently being used for cruise control is the map with the lower accuracy of road information (step S201—No), the control unit 34 sets the predetermined offset amount to a relatively small value (step S203).

After step S202 or S203, the control unit 34 shifts the position of the planned driving route from the center of the vehicle's own lane in the opposite direction to the adjacent lane in which the surrounding vehicle is traveling by the set offset amount, and causes the vehicle 10 to travel along the shifted planned driving route (step S204). The processor 23 then terminates the vehicle control process.

According to this variant, when the VLO function is being executed, the vehicle control device can prevent the vehicle from getting too close to lane markings, even if the accuracy of the road-related information displayed on the map used for cruise control is relatively low. As a result, this vehicle control device can reduce the driver's anxiety when the VLO function is being executed.

In yet another variant, the control unit 34 may set the target vehicle speed when the vehicle 10 is traveling around a curve when a map with less accurate road information is used for cruise control to be lower than the target vehicle speed when traveling around a curve when a map with more accurate road information is used for cruise control. This makes it possible to prevent the vehicle 10 from getting too close to lane markings, even when a map with relatively less accurate information is used for cruise control.

A computer program that realizes the functions of the processor 23 of the ECU 6 according to the above embodiment or variant may be provided in a form recorded on a computer-readable portable recording medium, such as a semiconductor memory, a magnetic recording medium, or an optical recording medium.

As described above, those skilled in the art will be able to make various modifications to suit the implementation form within the scope of the present invention.

1 Vehicle control system 10 Vehicle 2 Camera 3 GPS receiver 4 Wireless communication terminal 5 Storage device 6 Electronic control unit (ECU)
21 Communication interface 22 Memory 23 Processor 31 Switching point detection unit 32 Detection unit 33 Traveling lane determination unit 34 Control unit

Claims (10)

a storage unit that stores a first map and a second map that represent information about roads;
a detection unit that detects a preceding vehicle traveling ahead of the vehicle based on a sensor signal representing the surroundings of the vehicle, and estimates a distance between the vehicle and the preceding vehicle;
a determination unit that determines whether the preceding vehicle is traveling in the same lane in which the vehicle is traveling, based on the first map or the second map;
a control unit that controls the traveling of the vehicle based on the first map or the second map;
and
When the map used for controlling the traveling of the vehicle is switched from the first map to the second map, if the determination result of the lane in which the preceding vehicle is traveling changes from outside the own lane to the own lane and the distance between the vehicle and the preceding vehicle is less than a predetermined distance, the control unit suppresses a change amount per unit time of the deceleration of the vehicle until the distance between the vehicle and the preceding vehicle reaches the predetermined distance to a predetermined threshold or less.
Vehicle control device. a storage unit that stores a first map and a second map that represent information about roads;
a detection unit that detects a surrounding vehicle traveling in an adjacent lane adjacent to the lane in which the vehicle is traveling ;
a control unit that controls the traveling of the vehicle based on the first map or the second map;
and
The control unit
When a merging point where the adjacent lane merges into the own lane is displayed within a predetermined distance from the vehicle on the first map being used to control the traveling of the vehicle, the speed of the vehicle is reduced below a predetermined speed so that even if the surrounding vehicle merges into the own lane, the distance between the vehicle and the surrounding vehicle will be equal to or greater than a predetermined distance;
On the other hand, when the second map does not show the merging point and the map used to control the traveling of the vehicle is switched from the first map to the second map while the speed of the vehicle is being decelerated, the amount of change in the acceleration of the vehicle per unit time when the speed of the vehicle is accelerating until it reaches the predetermined speed is suppressed to a predetermined threshold value or less .
Vehicle control device. a storage unit that stores a first map and a second map that represent information about roads;
a control unit that controls vehicle travel based on the first map or the second map;
and
the control unit generates a planned driving route based on the map currently being used for controlling the driving of the vehicle, either the first map or the second map, such that the vehicle passes through a predetermined position in a width direction of the own lane in which the vehicle is traveling, and controls the vehicle so that the vehicle travels along the generated planned driving route;
When a map used for controlling the traveling of the vehicle is switched from the first map to the second map, if a position in the width direction of the planned traveling route changes, an amount of change in acceleration of the vehicle in the width direction per unit time until the position of the vehicle reaches the planned traveling route generated based on the second map is suppressed to a predetermined threshold value or less .
Vehicle control device. a storage unit that stores a first map that represents information about roads and a second map that represents information about the roads and has information about the roads that is less accurate than the first map;
a control unit that controls the vehicle based on the first map or the second map so that the vehicle travels in a position adjacent to the lane in which the vehicle is traveling and that is spaced from the center of the lane by a predetermined offset amount in a direction away from an adjacent lane in which another vehicle is traveling;
and
the control unit makes the predetermined offset amount smaller when controlling the traveling of the vehicle based on the second map than when controlling the traveling of the vehicle based on the first map.
Vehicle control device. Detecting a preceding vehicle traveling ahead of the vehicle based on a sensor signal representing the surroundings of the vehicle, and estimating a distance between the vehicle and the preceding vehicle;
determining whether the preceding vehicle is traveling in the lane in which the vehicle is traveling based on a first map representing information about a road or a second map representing information about the road;
controlling the travel of the vehicle based on the first map or the second map;
Controlling the running of the vehicle includes:
When the map used for controlling the traveling of the vehicle is switched from the first map to the second map, if the determination result of the lane in which the preceding vehicle is traveling changes from outside the own lane to the own lane and the distance between the vehicle and the preceding vehicle is less than a predetermined distance, suppressing the amount of change in deceleration of the vehicle per unit time until the distance between the vehicle and the preceding vehicle reaches the predetermined distance to a predetermined threshold or less.
A vehicle control method comprising: Detecting surrounding vehicles traveling in adjacent lanes adjacent to the lane in which the vehicle is traveling;
controlling the travel of the vehicle based on a first map representing information about roads or a second map representing information about the roads;
Controlling the running of the vehicle includes:
When a merging point where the adjacent lane merges into the own lane is displayed within a predetermined distance from the vehicle on the first map being used to control the traveling of the vehicle, the speed of the vehicle is reduced below a predetermined speed so that even if the surrounding vehicle merges into the own lane, the distance between the vehicle and the surrounding vehicle will be equal to or greater than a predetermined distance;
On the other hand, when the second map does not show the merging point and the map used to control the traveling of the vehicle is switched from the first map to the second map while the speed of the vehicle is being decelerated, the amount of change in the acceleration of the vehicle per unit time when the speed of the vehicle is accelerating until it reaches the predetermined speed is suppressed to a predetermined threshold value or less.
A vehicle control method comprising: controlling vehicle travel based on a first map representing information about roads or a second map representing information about the roads;
Controlling the running of the vehicle includes:
generating a planned driving route based on the map currently being used for controlling the driving of the vehicle, either the first map or the second map, so that the vehicle passes through a predetermined position in a width direction of the lane in which the vehicle is traveling, and controlling the vehicle so that the vehicle travels along the generated planned driving route;
When a map used for controlling the traveling of the vehicle is switched from the first map to the second map, if a position in the width direction of the planned traveling route changes, an amount of change in acceleration of the vehicle in the width direction per unit time until the position of the vehicle reaches the planned traveling route generated based on the second map is suppressed to a predetermined threshold value or less.
A vehicle control method comprising: Detecting a preceding vehicle traveling ahead of the vehicle based on a sensor signal representing the surroundings of the vehicle, and estimating a distance between the vehicle and the preceding vehicle;
determining whether the preceding vehicle is traveling in the lane in which the vehicle is traveling based on a first map representing information about a road or a second map representing information about the road;
controlling the travel of the vehicle based on the first map or the second map;
A vehicle control computer program for causing a processor mounted on the vehicle to execute the above,
Controlling the running of the vehicle includes:
When the map used for controlling the traveling of the vehicle is switched from the first map to the second map, if the determination result of the lane in which the preceding vehicle is traveling changes from outside the own lane to the own lane and the distance between the vehicle and the preceding vehicle is less than a predetermined distance, the deceleration is controlled so as to suppress the amount of change in the deceleration of the vehicle per unit time until the distance between the vehicle and the preceding vehicle reaches the predetermined distance to a predetermined threshold or less.
A computer program for vehicle control, comprising: Detecting surrounding vehicles traveling in adjacent lanes adjacent to the lane in which the vehicle is traveling;
controlling the travel of the vehicle based on a first map representing information about roads or a second map representing information about the roads;
A vehicle control computer program for causing a processor mounted on the vehicle to execute the above,
Controlling the running of the vehicle includes:
When a merging point where the adjacent lane merges into the own lane is displayed within a predetermined distance from the vehicle on the first map being used to control the traveling of the vehicle, the speed of the vehicle is reduced below a predetermined speed so that even if the surrounding vehicle merges into the own lane, the distance between the vehicle and the surrounding vehicle will be equal to or greater than a predetermined distance;
On the other hand, when the second map does not show the merging point and the map used for controlling the traveling of the vehicle is switched from the first map to the second map while the speed of the vehicle is being decelerated, the acceleration is controlled so as to suppress the amount of change in acceleration of the vehicle per unit time when the speed of the vehicle accelerates until it reaches the predetermined speed to be equal to or less than the predetermined threshold.
A computer program for vehicle control, comprising: controlling vehicle travel based on a first map representing information about roads or a second map representing information about the roads;
A vehicle control computer program for causing a processor mounted on the vehicle to execute the above,
Controlling the running of the vehicle includes:
generating a planned driving route based on the map currently being used for controlling the driving of the vehicle, either the first map or the second map, so that the vehicle passes through a predetermined position in a width direction of the lane in which the vehicle is traveling, and controlling the vehicle so that the vehicle travels along the generated planned driving route;
When a map used for controlling the traveling of the vehicle is switched from the first map to the second map, if a position in the width direction of the planned traveling route changes, an amount of change in acceleration of the vehicle in the width direction per unit time until the position of the vehicle reaches the planned traveling route generated based on the second map is suppressed to a predetermined threshold value or less.
A computer program for vehicle control, comprising: