Vehicle control device, vehicle control method, and computer program for vehicle control

Abstract

To provide a vehicle control device capable of executing the formulation of a driving plan at appropriate timing in response to switching of maps to be used.SOLUTION: A vehicle control device includes: a deviation section detection unit 31 that detects a deviation section where the information about a road which is represented on a first map and on which a vehicle 10 is traveling differs from the information about that road which is represented on a second map; a driving plan formulation unit 32 that formulates a first driving plan for a first section from a current position of the vehicle 10 to a start point of the deviation section or a control switching point set on the front side thereof on the basis of one of the first map and the second map, and, before the vehicle 10 reaches the control switching point, formulates a second driving plan for a second section which includes the deviation section beyond the control switching point on the basis of the other of the first map and the second map; and a control unit 34 that controls the vehicle 10 to follow the first driving plan for the first section and follow the second driving plan for the second section.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device, a vehicle control method, and a computer program for vehicle control. [Background technology]

[0002] Technologies are being researched that use map information to perform autonomous driving control of vehicles. However, vehicles may sometimes travel through areas where the accuracy of the map information is low. Therefore, technologies have been proposed to enable the continuation of autonomous driving even when traveling through areas with low map information accuracy (see Patent Document 1).

[0003] The driving control method disclosed in Patent Document 1 calculates a route from the vehicle's current position to its destination by referring to map information having a first map containing lane identification information and a second map not containing lane identification information. Furthermore, this driving control method sets a first driving control when traveling along a first route belonging to the first map, and sets a second driving control with fewer executable controls than the first driving control when traveling along a second route belonging to the second map, and formulates a driving plan to have the vehicle travel along that route with the content of the set driving control. This driving control method then presents the driving plan, which includes control change points where the first driving control and the second driving control switch, to the vehicle occupants before the start of execution of the driving plan. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 6721118 [Overview of the project] [Problems that the invention aims to solve]

[0005] In some cases, multiple maps may be available for creating a driving plan for the same road section. In such cases, it is necessary to appropriately determine the point at which the map used for planning the driving plan should be switched. Furthermore, when a map switch occurs, it is necessary to appropriately set the timing for creating the driving plan.

[0006] Therefore, the present invention aims to provide a vehicle control device that can formulate a driving plan in conjunction with switching the map being used at an appropriate timing. [Means for solving the problem]

[0007] According to one embodiment, a vehicle control device is provided. This vehicle control device includes a storage unit that stores a first map and a second map representing road information; a divergence section detection unit that detects a divergence section in the direction of travel of the vehicle where the road information shown on the first map and the road information shown on the second map diverge from each other; a driving plan formulation unit that formulates a first driving plan for a first section from the vehicle's current position to the vehicle's starting point of the divergence section or a control switching point set closer to the vehicle than the starting point, based on one of the first map and the second map, and before the vehicle reaches the control switching point, formulates a second driving plan for a second section including the divergence section beyond the control switching point, based on the map of the first map and the second map that is different from the map used for the first section; and a control unit that controls the vehicle so that it travels in the first section according to the first driving plan, and controls the vehicle so that it travels in the second section according to the second driving plan.

[0008] In this vehicle control device, the driving plan formulation unit formulates a first driving plan based on a first map and a second driving plan based on a second map, wherein the accuracy of the road information shown on the first map is higher than the accuracy of the road information shown on the second map, and the update frequency of the second map is higher than the update frequency of the first map.

[0009] Furthermore, in this vehicle control device, it is preferable that the deviation section detection unit detects deviation sections such that the distance between the location of a predetermined feature on or around a road shown on the first map and the location of a corresponding predetermined feature shown on the second map is greater than or equal to a predetermined threshold, or that the presence or absence of a predetermined feature differs between the first map and the second map.

[0010] Another embodiment provides a vehicle control method. This vehicle control method includes detecting a divergence section in the direction of travel of the vehicle where information about the road the vehicle is traveling on, as shown on a first map, and information about the road the vehicle is traveling on, as shown on a second map, diverge from each other; formulating a first driving plan based on one of the first map and the second map for a first section from the vehicle's current position to the vehicle's starting point of the divergence section or a control switching point set closer to the vehicle than the starting point; formulating a second driving plan based on the map different from the one used for the first section for a second section including the divergence section beyond the control switching point, before the vehicle reaches the control switching point; controlling the vehicle so that it travels in accordance with the first driving plan for the first section; and controlling the vehicle so that it travels in accordance with the second driving plan for the second section.

[0011] In yet another embodiment, a computer program for vehicle control is provided. This computer program for vehicle control includes instructions to cause a processor mounted on the vehicle to perform the following actions: detect a divergence section in the direction of travel of the vehicle where information about the road the vehicle is traveling on, as shown on a first map, and information about the road the vehicle is traveling on, as shown on a second map, diverge from each other; formulate a first driving plan for a first section from the vehicle's current position to the vehicle's starting point of the divergence section or a control switching point set to be closer to the vehicle than the starting point, based on one of the first map and the second map; formulate a second driving plan for a second section, including the divergence section beyond the control switching point, before the vehicle reaches the control switching point, based on the map of the first map and the second map that is different from the map used for the first section; control the vehicle so that it travels in the first section according to the first driving plan; and control the vehicle so that it travels in the second section according to the second driving plan. [Effects of the Invention]

[0012] The vehicle control device according to the present invention has the effect of being able to formulate a driving plan at an appropriate timing in conjunction with the switching of the map being used. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram of the vehicle control system in which the vehicle control device is implemented. [Figure 2] This is a hardware configuration diagram of an electronic control unit, which is one embodiment of a vehicle control system. [Figure 3] This is a functional block diagram of the processor in an electronic control unit related to vehicle control processing. [Figure 4] (a) and (b) are conceptual diagrams illustrating an example of the relationship between the degree of discrepancy and the discrepancy interval between two maps. [Figure 5] This is a conceptual diagram illustrating an example of detecting a deviation interval through modification. [Figure 6]This figure is a diagram explaining an overview of individual operation plans established as deviation sections and the display timing thereof. [Figure 7] It is an operation flowchart of vehicle control processing. MODE FOR CARRYING OUT THE INVENTION

[0014] Hereinafter, a vehicle control device, a vehicle control method executed on the vehicle control device, and a computer program for vehicle control will be described with reference to the drawings. The vehicle control device formulates a travel plan using either of two maps, and causes the vehicle to travel in accordance with the formulated travel plan. More specifically, the vehicle control device detects, in a section from the current position of the vehicle to a point a predetermined distance ahead in the traveling direction of the vehicle, a deviation section where pieces of information about the road on which the vehicle is traveling, which are respectively represented on the two maps, deviate from each other. The vehicle control device formulates a first operation plan based on one of a first map and a second map for a first section from the current position of the vehicle to the start point of the deviation section on the vehicle side, or to a control switching point set closer to the vehicle than the start point. Further, the vehicle control device formulates a second operation plan for a second section beyond the control switching point including the deviation section, based on the map, of the first map and the second map, different from the map used for the first section. Then, the vehicle control device controls the vehicle such that the vehicle travels according to the first operation plan for the first section, and controls the vehicle such that the vehicle travels according to the second operation plan for the second section.

[0015] In this embodiment, the driving plan refers to a plan that defines the actions that the vehicle or vehicle control device should take in the future. For example, if the road leading to the vehicle's destination branches off from the road the vehicle is currently traveling on, the driving plan includes one or more lane changes to be performed up to that branching point. Similarly, if the vehicle is scheduled to turn right or left at an intersection a predetermined distance away in order to reach its destination, the driving plan includes one or more lane changes to be performed up to that intersection. Furthermore, the driving plan may include speed control according to the structure of the road the vehicle is traveling on or the speed limit. Moreover, the driving plan may include the termination of automated driving control (i.e., handover to the driver) at a point a predetermined distance from the vehicle's current position on the road the vehicle is traveling on.

[0016] In this embodiment, each of the two maps includes information related to roads, such as information representing the types of features like road markings such as lane markings, curbs, road signs, and roadside billboards, as well as information representing the locations of these features, which is used in formulating driving plans. Preferably, the update timings of these two maps are different. In this embodiment, the timing of a map update refers to the timing when the road information represented on the map is updated. For example, if a map server that manages maps or distributes maps to vehicles updates the information for a predetermined road section of either map at a first date and time, that first date and time becomes the update timing for that map.

[0017] Furthermore, it is preferable that the map with higher accuracy in the road information shown on the two maps be designated as the standard map (hereinafter referred to as the first map). This increases the likelihood of developing an appropriate driving plan. The accuracy of the road information shown on the map is considered higher if the error in the position of the roads or features around those roads is small, or if the type and presence of those features are certain. Therefore, for road sections where there have been no changes since the last update of either the first map or the other map (hereinafter referred to as the second map), it is preferable that the accuracy of the position of features and the certainty of the type and presence of features in that road section are higher in the first map than in the second map. However, the accuracy of the road information in each of the two maps may be the same.

[0018] On the other hand, it is preferable that the update frequency of the second map is higher than that of the first map. This means that, for example, even if the first map does not accurately represent information about a given road section because some construction work was carried out on that section after the first map was last updated, the second map may have been last updated later than when the construction work was carried out on that section. Therefore, the second map may accurately represent information about that given road section. Thus, the vehicle control device can formulate an appropriate driving plan by using the first and second maps appropriately depending on the situation.

[0019] Figure 1 is a schematic diagram of a vehicle control system on which a vehicle control device is implemented. Figure 2 is a hardware diagram of an electronic control device, which is one embodiment of the vehicle control device. In this embodiment, the vehicle control system 1, which is mounted on and controls the vehicle 10, 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 communicated via an in-vehicle network compliant with standards such as a controller area network. The vehicle control system 1 may further include a distance measuring sensor (not shown), such as LiDAR or radar, for measuring the distance from the vehicle 10 to objects in the vicinity of the vehicle 10. The vehicle control system 1 may also further include a navigation device (not shown) for searching for a route to a destination.

[0020] Camera 2 is an example of a sensor that generates sensor signals 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 vehicle 10 so as to face forward of the vehicle 10. Camera 2 photographs the area in front of vehicle 10 at predetermined shooting cycles (e.g., 1 / 30 second to 1 / 10 second) and generates an image of that area. 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 shooting directions or focal lengths.

[0021] Camera 2 outputs the generated image to ECU 6 via the in-vehicle network each time it generates an image.

[0022] The GPS receiver 3 receives GPS signals from GPS satellites at predetermined intervals and determines the vehicle's position based on the received GPS signals. At predetermined intervals, the GPS receiver 3 outputs positioning information representing the vehicle's position based on the GPS signals to the ECU 6 via the in-vehicle network. The vehicle 10 may also have a receiver that determines its own position by receiving positioning signals from satellites of another satellite positioning system, instead of a GPS receiver.

[0023] The wireless communication terminal 4 communicates wirelessly with the 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.

[0024] The storage device 5 is an example of a storage unit and includes, for example, a hard disk drive, a non-volatile semiconductor memory, or an optical recording medium and its access device. The storage device 5 stores the first map and the second map, and update information for each of the first map and the second map, which indicates the date and time when the information about the individual road sections represented on the map was last updated.

[0025] Furthermore, the storage device 5 has a processor for performing tasks such as updating the first or second map and processing requests for reading maps from the ECU 6. For example, each time the vehicle 10 moves a predetermined distance, the storage device 5 sends a request to the map server via the wireless communication terminal 4 to acquire the first and second maps, along with the vehicle 10's current location. The storage device 5 then receives map information from the map server via the wireless communication terminal 4, including the first and second maps for a predetermined area around the vehicle 10's current location, and stores the first and second maps included in the received map information. The storage device 5 also stores update information for the first or second map when it receives such information via the wireless communication terminal 4. Furthermore, when the storage device 5 receives a request to read a map from the ECU 6, it extracts a range from the stored first and second maps that includes the vehicle 10's current location and is relatively smaller than the predetermined area, and outputs it to the ECU 6 via the in-vehicle network.

[0026] The ECU 6 controls the vehicle 10 for automatic driving. In this embodiment, the ECU 6 formulates a driving plan based on a first map or a second map and controls the vehicle 10 for automatic driving so that it drives according to the formulated driving plan.

[0027] As shown in Figure 2, the ECU 6 includes 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 they may be integrated as a single integrated circuit.

[0028] The communication interface 21 has an interface circuit for connecting the ECU 6 to the in-vehicle network. Whenever the communication interface 21 receives an image from the camera 2, it passes the received image to the processor 23. Also, whenever the communication interface 21 receives positioning information from the GPS receiver 3, it passes that 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.

[0029] Memory 22 is another example of a storage unit, and may include, for example, volatile semiconductor memory and non-volatile semiconductor memory. Memory 22 stores various data used in vehicle control processing performed by processor 23. For example, memory 22 stores images of the vehicle 10's surroundings 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. Furthermore, memory 22 stores parameters of camera 2 such as focal length, shooting direction and mounting position, and various parameters for identifying object detection classifiers used for detecting features and other objects. In addition, memory 22 temporarily stores various data generated during vehicle control processing.

[0030] The processor 23 has one or more CPUs (Central Processing Units) and their peripheral circuits. The processor 23 may further have other arithmetic circuits such as a logic unit, a numerical unit, or a graphics processing unit. The processor 23 then performs vehicle control processing for the vehicle 10 at predetermined intervals.

[0031] Figure 3 is a functional block diagram of the processor 23 related to vehicle control processing. The processor 23 includes a deviation section detection unit 31, a driving plan formulation unit 32, a presentation processing unit 33, and a control unit 34. Each of these parts of the processor 23 is, for example, a functional module realized by a computer program running on the processor 23. Alternatively, each of these parts of the processor 23 may be a dedicated arithmetic circuit provided on the processor 23.

[0032] The discrepancy section detection unit 31 detects a discrepancy section in the direction of travel of the vehicle 10, from the vehicle 10's current position to a predetermined distance ahead, where the information about the road the vehicle 10 is traveling on, as shown on the first map, differs from the information shown on the second map.

[0033] To this end, the deviation section detection unit 31 sets the position of the vehicle 10 indicated by the latest positioning information as the vehicle 10's current position. The deviation section detection unit 31 also determines the direction of travel of the vehicle 10 based on the changes in the vehicle 10's position indicated by multiple recent positioning data, or based on the sensor signal indicating the vehicle 10's orientation received by the ECU 6 from a compass sensor (not shown) mounted on the vehicle 10. Furthermore, the deviation section detection unit 31 refers to the map currently being used to formulate the driving plan from the first map and the second map to identify the road containing the vehicle 10's current position as the road the vehicle 10 is traveling on.

[0034] The deviation section detection unit 31 sets sampling points at first intervals (for example, several hundred meters to 1 kilometer) in a section from the current position of the vehicle 10 to a predetermined distance ahead along the direction of travel of the vehicle 10. For each sampling point, the deviation section detection unit 31 calculates the deviation degree as the distance between the position of the road or surrounding features (for example, lane markings, curbs, guardrails, or road signs) that the vehicle 10 is traveling on, as shown on the first map, and the position of the corresponding feature shown on the second map. In the case where features that are continuous along the road, such as lane markings in the above example, are used to calculate the deviation degree, the deviation section detection unit 31 only needs to calculate the deviation degree as the distance from the position of the feature shown on the first map at the sampling point of interest to the nearest position of the corresponding feature shown on the second map. The deviation interval detection unit 31 may calculate the deviation degree as the average 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.

[0035] The deviation interval detection unit 31 compares the degree of deviation calculated for each sampling point with a predetermined threshold. The deviation interval detection unit 31 then identifies sampling points where the degree of deviation is greater than or equal to the predetermined threshold. The deviation interval detection unit 31 resets sampling points at second intervals (for example, several tens to 100 meters) that are narrower than the first interval, before and after the sampling points where the degree of deviation is greater than or equal to the predetermined threshold. The deviation interval detection unit 31 then calculates the degree of deviation between the first map and the second map for each reset sampling point, in the same manner as above. The deviation interval detection unit 31 then identifies sampling points among the reset sampling points where the degree of deviation is greater than or equal to the predetermined threshold. The deviation interval detection unit 31 then detects a deviation interval from the sampling point immediately preceding the sampling point closest to the vehicle 10 among the sampling points where the deviation degree is above a predetermined threshold, to the sampling point immediately following the sampling point furthest from the vehicle 10 among the sampling points where the deviation degree is above a predetermined threshold. The deviation interval detection unit 31 may detect multiple deviation intervals by repeating the above process.

[0036] Figures 4(a) and 4(b) are conceptual diagrams illustrating an example of the relationship between the degree of discrepancy and the discrepancy interval between two maps. Note that in Figure 4(a), vehicle 10 is exaggerated in its representation. As shown in Figure 4(a), on the road where vehicle 10 is traveling, sampling points S are set at first intervals from the current position P of vehicle 10. i (i=1,2,...,m) is set. Then sampling point S i For each case, the degree of deviation D between lane marking 401 shown on the first map and the corresponding lane marking 402 shown on the second map. i This is calculated. In this example, the sampling point S B In this case, the degree of deviation D B The threshold Th is above a predetermined threshold.

[0037] Therefore, as shown in Figure 4(b), sampling point S B Before and after, sampling point S at the second interval j(j=B-n, B-(n-1), ..., B-1, B, B+1, ..., B+n) is reset. And sampling point S j for each, the deviation D between the lane marking 401 represented on the first map and the corresponding lane marking 402 represented on the second map j is calculated. In this example, the sampling point S B-a to the sampling point S B+b in the section, the deviation D j is equal to or greater than the predetermined threshold Th. Therefore, the sampling point S B-a on the immediately preceding side of the sampling point S B-a-1 to the sampling point S B+b on the immediately next side of the sampling point S B+b+1 up to is specified as the deviation section A.

[0038] Note that the deviation section detection unit 31 may set a deviation degree equal to or higher than a predetermined threshold for sampling points where the number of lanes or the number of lane markings differs between the first map and the second map. Further, the deviation section detection unit 31 may also set a deviation degree equal to or higher than a predetermined threshold for sampling points where the type of lane marking differs between the first map and the second map. Furthermore, the deviation section detection unit 31 may set points where the presence or absence of a predetermined feature such as a road sign or a guardrail differs between the first map and the second map as sampling points having a deviation degree equal to or higher than the predetermined threshold.

[0039] In a modified version, the deviation section detection unit 31 may calculate the degree of deviation at predetermined intervals (for example, several tens of meters to 100 meters) starting from the point closest to the current position of the vehicle 10 along the direction of travel of the vehicle 10, in the same manner as in the embodiment described above. The deviation section detection unit 31 then defines the point where the degree of deviation first exceeds a first threshold (for example, the same threshold as the predetermined threshold described above) as the starting point, which is the vehicle 10 side of the deviation section. The deviation section detection unit 31 then defines the point where the degree of deviation first falls below a second threshold, among the points further from the vehicle 10 than the starting point of the deviation section, as the ending point, which is the farther end of the deviation section from the vehicle 10. The second threshold for identifying the ending point of the deviation section may be set lower than the first threshold for identifying the starting point of the deviation section. This prevents the deviation section from being set in such a way that it frequently switches between deviation sections and other sections, or from being misdetected as the end point of a deviation section. Preferably, each of the above thresholds is set to a value greater than the mean, median, or mode of the positional errors of individual features shown on the first and second maps. This prevents points where there is virtually no difference between the road information shown on the first map and the road information shown on the second map from being mistakenly included in the deviation section.

[0040] Furthermore, if the distance between two consecutive divergence intervals is less than a predetermined distance threshold (for example, several hundred meters to 1 kilometer), the divergence interval detection unit 31 may set a single consecutive interval containing those two divergence intervals as a single divergence interval. Similarly, for three or more divergence intervals, if the distance between two consecutive divergence intervals is less than the distance threshold, the divergence interval detection unit 31 may set a single consecutive interval containing those three or more divergence intervals as a single divergence interval. This prevents the map used to generate the driving plan from switching frequently, thus preventing the driving plan from switching frequently. As a result, the vehicle 10 is prevented from exhibiting unnatural behavior, thus preventing the driver from feeling unnecessary anxiety.

[0041] Figure 5 is a conceptual diagram showing an example of the detection of deviation sections using this modified method. In the example shown in Figure 5, five deviation sections 501 to 505 are detected based on the degree of deviation at individual points on the road while the vehicle 10 is traveling. However, the distance d between deviation section 501 and deviation section 502 is not considered. 12 The distance d between deviation interval 502 and deviation interval 503 is less than the predetermined distance threshold Thd. 23 , and the distance d between deviation section 503 and deviation section 504 34 However, it is also below the predetermined distance threshold Thd. On the other hand, the distance d between deviation interval 504 and deviation interval 505 45 This is greater than or equal to a predetermined distance threshold Thd. Therefore, section 510, from the start point of deviation section 501 to the end point of deviation section 504, is detected again as a deviation section. However, deviation section 505 is maintained as a separate deviation section from deviation section 510.

[0042] The deviation section detection unit 31 notifies the operation plan formulation unit 32 of the start and end points of the detected deviation section.

[0043] The driving plan formulation unit 32 generates a driving plan from the current position of the vehicle 10 to a predetermined distance ahead, based on either the first map or the second map. In this embodiment, the driving plan formulation unit 32 formulates a first driving plan for a first section from the current position of the vehicle 10 to the start point of the deviation section or a control switching point set closer to the vehicle 10 than the start point, based on either the first map or the second map. The control switching point is set, for example, to a position closer to the current position of the vehicle 10 by a control switching offset distance than the start point of the deviation section. The control switching offset distance is set, for example, to about 0m to several hundredm. In particular, by setting the control switching offset distance to a distance that is not 0, for example, to about 100m to several hundredm, it is possible to prevent the driving plan from being suddenly changed even if there is a point near the start point where it is necessary to change the behavior of the vehicle 10. Furthermore, the map used in formulating the first driving plan may be the map used in formulating the driving plan that vehicle 10 follows at its current location, out of the first and second maps.

[0044] Furthermore, the operation plan formulation unit 32 formulates a second operation plan for the second section beyond the control switching point before the vehicle 10 reaches the control switching point, based on the map that is different from the map used for the first section among the first map and the second map. The second section is set as the section from the control switching point to the end point, which is the endpoint of the divergence section furthest from the vehicle 10, or a point near it, so as to include the divergence section.

[0045] As described above, if the accuracy of the first map is higher than that of the second map regarding road information, the driving plan formulation unit 32 preferably formulates a driving plan based on the first map for the first section where the information shown on the first map and the information shown on the second map do not deviate. Furthermore, if the update frequency of the second map is higher than that of the first map, the driving plan formulation unit 32 preferably formulates a driving plan based on the second map for the second section beyond the control switching point, including the deviating section. However, this is not limited to this example, and if there is no substantial difference between the accuracy of the first map and the second map regarding road information, the driving plan formulation unit 32 may formulate a driving plan based on the second map for the first section. Furthermore, if the elapsed time since the last update of road information for the second section is shorter on the first map than on the second map, the operation plan formulation unit 32 prefers to formulate the operation plan for the second section beyond the control switching point based on the first map. For the sake of explanation, the map used to formulate the operation plan for the first section may be referred to as the field map. The map used to formulate the operation plan for the second section may be referred to as the alternative map.

[0046] The driving plan formulation unit 32 refers to the field map and detects points in the first section that will trigger actions that the vehicle 10 should take. For example, the driving plan formulation unit 32 refers to the driving route to the destination of the vehicle 10, received by the ECU 6 from the navigation device (not shown), and the field map, and determines whether there is a branching point in the first section where a lane leading to the destination branches off from the road the vehicle 10 is currently traveling on. If such a branching point exists, the driving plan formulation unit 32 determines whether the lane the vehicle 10 is currently traveling in (hereinafter referred to as the vehicle's lane) and the lane leading to the destination are different. If the vehicle's lane and the lane leading to the destination are different, the driving plan formulation unit 32 formulates a driving plan that involves one or more lane changes, with the lane leading to the destination as the target lane.

[0047] To determine whether the vehicle's own lane is different from the target lane, the driving plan formulation unit 32 detects the vehicle's own lane. To do this, the driving plan formulation unit 32 detects the vehicle's own lane by comparing an image (hereinafter sometimes simply referred to as "image") generated by the camera 2, which represents the area around the vehicle 10, with a site map. For example, the driving plan formulation unit 32 assumes the position and orientation of the vehicle 10 and projects road or surrounding features detected from the image onto the site map, or projects road or surrounding features around the vehicle 10 shown on the site map onto the image. These road or surrounding features can be, for example, road markings such as lane markings or stop lines, or curbs. The driving plan formulation unit 32 then estimates the position and orientation of the vehicle 10 at which the features detected from the image and the features shown on the site map best match as the vehicle 10's actual position, and detects the lane containing that position on the site map as the vehicle's own lane.

[0048] The driving plan formulation unit 32 determines the position where features are projected on the field map or image using the initial values ​​of the assumed position and orientation of the vehicle 10, and the parameters of the camera 2, such as focal length, installation height, and shooting direction. The initial values ​​of the position and orientation of the vehicle 10 are either the latest position of the vehicle 10 measured by the GPS receiver 3, or the position of the vehicle 10 estimated during the previous lane detection, corrected using odometry information. The driving plan formulation unit 32 then calculates the degree of agreement between features on or around the road detected from the image and the corresponding features represented on the field map (for example, the reciprocal of the sum of the squares of the distances between the corresponding features).

[0049] The driving plan formulation unit 32 repeats the above process while changing the assumed position and orientation of the vehicle 10. The driving plan formulation unit 32 then estimates the assumed position and orientation when the degree of agreement is maximized as the actual position of the vehicle 10. The driving plan formulation unit 32 then refers to the field map and identifies the lane in which the vehicle 10's position is located as its own lane.

[0050] The operation planning unit 32 can detect features by inputting an image into a classifier that has been pre-trained to detect features from an image. The operation planning unit 32 can use a deep neural network (DNN) with a convolutional neural network (CNN) architecture, such as a Single Shot MultiBox Detector or Faster R-CNN, as such a classifier. Alternatively, the operation planning unit 32 may use a DNN with a self-attention network (SAN) architecture, such as a Vision Transformer, as such a classifier.

[0051] Furthermore, the driving plan formulation unit 32 identifies the target lane by referring to the site map and the driving route. The driving plan formulation unit 32 then refers to the site map to determine whether the current lane and the target lane are the same lane. If the current lane and the target lane are not the same lane, the driving plan formulation unit 32 determines that the current lane and the target lane are different. Furthermore, if the current lane and the target lane are different, the driving plan formulation unit 32 refers to the site map to count the number of lanes from the current lane to the target lane and formulates a driving plan that involves changing lanes that many times.

[0052] Similarly, the driving plan formulation unit 32 refers to the driving route of the vehicle 10 to its destination and the site map to determine whether there is an intersection within the first section where the vehicle 10 must turn right or left from the road it is currently traveling on to reach its destination. If such an intersection exists, the driving plan formulation unit 32 determines whether the vehicle's own lane is different from the lane on which it can turn right or left. If the vehicle's own lane is different from the lane on which it can turn right or left, the driving plan formulation unit 32 formulates a driving plan that involves one or more lane changes, with the lane on which it can turn right or left as the target lane.

[0053] Furthermore, the driving plan formulation unit 32 determines whether there is a section within the first section where a different speed limit is set than the speed limit at the vehicle 10's current position. If such a section exists, the driving plan formulation unit 32 formulates a driving plan that changes the target speed of the vehicle 10 to the speed limit for that section when it enters that section.

[0054] Furthermore, the driving plan formulation unit 32 determines whether there is a point within the first section where the automated driving control will end (for example, an entrance or exit to an expressway). If such a point exists, the driving plan formulation unit 32 formulates a driving plan that transfers driving control to the driver up to that point.

[0055] Furthermore, if there is no point within the first section that would trigger an action that vehicle 10 should take, the driving plan formulation unit 32 formulates a driving plan in which vehicle 10 continues to travel in its own lane.

[0056] The driving plan formulation unit 32 should formulate a driving plan for the second section beyond the control switching point, similar to the driving plan for the first section. However, unlike the first section, for the second section, the driving plan formulation unit 32 should refer to an alternative map to detect points that trigger actions that the vehicle 10 should take. The driving plan formulation unit 32 should also refer to the alternative map to determine whether the vehicle's lane and the target lane are different. In this way, a driving plan for the divergence section is formulated before the vehicle 10 reaches the divergence section. This prevents the driving plan from being suddenly changed even if the map used to formulate the driving plan changes. Therefore, it prevents the driver from feeling uneasy due to changes in the driving plan. For the sake of explanation, the driving plan for the first section will be referred to as the first driving plan, and the driving plan for the second section will be referred to as the second driving plan.

[0057] Furthermore, the operation plan formulation unit 32 may formulate the operation plan for the section beyond the end point of the divergence section by referring to the on-site map again.

[0058] The operation plan formulation unit 32 notifies the presentation processing unit 33 and the control unit 34 of the first and second operation plans that it has formulated.

[0059] The presentation processing unit 33 notifies the driver of the first and second driving plans it has formulated via a notification device (not shown) installed inside the vehicle. In this embodiment, the presentation processing unit 33 presents the first driving plan to the driver via the notification device until the vehicle 10 reaches a display switching point, which is set to be closer to the vehicle 10's current position by a display switching offset distance than the deviation section. On the other hand, when the vehicle 10 reaches the display switching point, the presentation processing unit 33 switches the driving plan presented to the driver via the notification device from the first driving plan to the second driving plan. The presentation processing unit 33 only needs to determine whether the vehicle 10 has reached the display switching point based on the latest position of the vehicle 10 determined by the GPS receiver 3. The display switching offset distance is set to a value larger than the control switching offset distance described above, for example, several hundred meters to about 1 kilometer. That is, the display switching point is set closer to the vehicle 10's current position than the control switching point.

[0060] In this way, the presentation processing unit 33 switches the driving plan presented to the driver from the first driving plan to the second driving plan before the vehicle 10 actually reaches the point where the control of the vehicle 10 is switched. This prevents the presented driving plan from switching just before the behavior of the vehicle 10 changes, so that the presentation processing unit 33 can suppress the driver from feeling anxious or uncomfortable with the presented driving plan and the behavior of the vehicle 10.

[0061] Figure 6 is a diagram illustrating the divergence section, the individual driving plans formulated, and the timing of their display. In Figure 6, for road 600 on which vehicle 10 is traveling, lane information represented by the first map is shown as a solid line, and lane information represented by the second map is shown as a dotted line. As shown in the figure, in section 601, which is further from vehicle 10 than point P1, there is a divergence between the information on road 600 represented by the first map and the information on road 600 represented by the second map. In other words, section 601 is a divergence section. The first and second maps show that within the divergence section 601, the lane leading to the destination branches off from road 600. Furthermore, it is assumed that the update timing of the second map for the divergence section 601 is later than that of the first map, and the second map shows the latest information for the divergence section 601.

[0062] In this embodiment, for the first section 602, which is located on the side of the vehicle 10's current position from the control switching point Pc, which is located a control switching offset distance before point P1 where the divergence section 601 begins, a first driving plan is formulated based on a first map, which is a field map. In this example, there are no points in the first section 602 that would trigger an action that the vehicle 10 should take. Therefore, in the first driving plan, the vehicle 10 is planned to travel along its own lane, which it is currently traveling in. On the other hand, for the second section 603, which includes the divergence section 601 and extends beyond the control switching point Pc, a second driving plan is formulated based on a second map, which is an alternative map. In particular, in this example, the first map, which is a field map, shows that a lane branching off from the current lane towards the destination, while the second map, which is an alternative map, shows that a lane branching off from a lane adjacent to the current lane towards the destination. Therefore, the second driving plan includes one or more lane changes from the current lane to the lane leading to the destination. In this way, by using the alternative map in formulating the driving plan for the second section 603, an appropriate driving plan can be formulated.

[0063] In the first section 602, the vehicle 10 is controlled according to the first driving plan, while in the second section 603, the vehicle 10 is controlled according to the second driving plan. Furthermore, the first driving plan is presented to the driver until the vehicle 10 reaches the display switching point Pd, which is located a distance before point P1 by the display switching offset distance. After the vehicle 10 has passed the display switching point Pd, the second driving plan is presented to the driver.

[0064] For example, if the presented driving plan includes one or more lane changes, the presentation processing unit 33 displays an image or icon representing those one or more lane changes on a display device, which is an example of a notification device. Alternatively, the presentation processing unit 33 may output an audio signal representing those one or more lane changes from a speaker, which is another example of a notification device. Similarly, if the presented driving plan includes the vehicle 10 turning right or left at a predetermined intersection, the presentation processing unit 33 displays an image or icon representing the predetermined intersection and the right or left turn at that intersection on the display device. Alternatively, the presentation processing unit 33 may output an audio signal representing the predetermined intersection and the right or left turn at that intersection from a speaker. Furthermore, if the presented driving plan includes the transfer of driving control to the driver, the presentation processing unit 33 displays an image or icon representing the driver change request on the display device before the vehicle 10 reaches the point where automatic driving control ends. Alternatively, the presentation processing unit 33 may output an audio signal representing the driver change request from a speaker. In this case, the notification processing unit 33 may notify the driver of the request for a change of driver via two or more notification devices.

[0065] The control unit 34 controls each part of the vehicle 10 to drive the vehicle 10 according to the first and second driving plans received from the driving plan formulation unit 32. In this embodiment, the control unit 34 controls the vehicle 10 so that it drives according to the first driving plan while the vehicle 10 is traveling through the first section, that is, until the vehicle 10 reaches the control switching point. The control unit 34 also controls the vehicle 10 so that it drives according to the second driving plan while the vehicle 10 is traveling through the second section beyond the control switching point. The control unit 34 can determine whether or not the vehicle 10 has reached the control switching point based on the latest position of the vehicle 10 determined by the GPS receiver 3.

[0066] The control unit 34 generates a planned route (hereinafter simply referred to as the planned route) for the vehicle 10, according to the driving plan used for controlling the vehicle 10 in the section in which the vehicle 10 is currently traveling, from among the first and second driving plans. For example, if the driving plan used for controlling the vehicle 10 includes one or more lane changes for the vehicle 10 to move to a target lane, the control unit 34 generates a planned route that moves from the current lane to the target lane. If the driving plan used for controlling the vehicle 10 does not include lane changes, the control unit 34 generates a line passing through the center of the current lane as the planned route. The control unit 34 may refer to the local map until the vehicle 10 reaches the control switching point, and then refer to an alternative map after the vehicle 10 reaches the control switching point to generate the planned route.

[0067] 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 route generated according to the driving plan created for the section the vehicle 10 is currently traveling. The control unit 34 can accurately measure the position of the vehicle 10 by comparing the image obtained by the camera 2 with the map used to generate the planned route, as described in the driving plan formulation unit 32. If the measured position of the vehicle 10 is on the planned route, the control unit 34 determines the steering angle of the vehicle 10 so that it moves along the planned route and controls the steering of the vehicle 10 to achieve the determined steering angle. If the measured position of the vehicle 10 is away from the planned route, the control unit 34 determines the steering angle of the vehicle 10 so that it moves closer to the planned route and controls the steering of the vehicle 10 to achieve the determined steering angle. The control unit 34 also controls the accelerator and brakes so that the speed of the vehicle 10 approaches the target speed. Furthermore, if the driving plan includes the vehicle 10 stopping at a specific point, the control unit 34 controls the accelerator and brakes so that the vehicle 10 stops at that specific point.

[0068] Furthermore, the control unit 34 sets the acceleration and deceleration of vehicle 10 so that the distance between vehicle 10 and other vehicles traveling in front of it is maintained at or above a certain distance. To this end, the control unit 34 detects other vehicles by inputting the image obtained by camera 2 or the distance measurement signal obtained by distance measurement sensor (not shown) into a classifier that has been pre-trained to detect other vehicles. The control unit 34 then estimates the distance between vehicle 10 and other vehicles based on the size of the other vehicles in the image, the position of the lower edge of the area where the other vehicles are represented, or the distance indicated by the distance measurement signal in the direction to the detected other vehicles. When the distance between vehicle 10 and other vehicles falls below a predetermined distance threshold, the control unit 34 sets the acceleration and deceleration of vehicle 10 to slow down vehicle 10. On the other hand, if the distance between vehicle 10 and other vehicles is above the predetermined distance threshold, the control unit 34 sets the acceleration and deceleration of vehicle 10 to maintain a constant speed or to approach the speed limit of the road on which vehicle 10 is traveling or a target speed set by the driver. The control unit 34 then sets the accelerator opening or brake amount according to the set acceleration / deceleration. The control unit 34 determines the fuel injection amount according to the set accelerator opening and outputs a control signal corresponding to that fuel injection amount to the fuel injection device of the vehicle 10's engine. Alternatively, the control unit 34 determines the amount of power to be supplied to the motor according to the set accelerator opening and controls the motor drive circuit so that that amount of power is supplied to the motor. Or, the control unit 34 also outputs a control signal corresponding to the set brake amount to the brakes of the vehicle 10.

[0069] Figure 7 is an operation flowchart of the vehicle control process executed by the processor 23. The processor 23 should execute the vehicle control process according to the following operation flowchart each time the vehicle 10 travels a predetermined distance or each time a predetermined amount of time has elapsed.

[0070] The deviation section detection unit 31 of the processor 23 detects a deviation section in the direction of travel of the vehicle 10, from the current position of the vehicle 10 to a predetermined distance ahead, where the information on the road the vehicle 10 is traveling on, as shown on the first map, differs from the information shown on the second map (step S101). The driving plan formulation unit 32 of the processor 23 then formulates a first driving plan for the first section from the current position of the vehicle 10 to the start point of the deviation section or a control switching point set closer to the vehicle 10, by referring to a local map (step S102). Furthermore, the driving plan formulation unit 32 then formulates a second driving plan for the second section beyond the control switching point, including the deviation section, by referring to an alternative map (step S103).

[0071] The presentation processing unit 33 of the processor 23 determines whether or not the vehicle 10 has reached the display switching point (step S104). If the vehicle 10 has not reached the display switching point (step S104-No), the presentation processing unit 33 presents the first driving plan to the driver via the notification device (step S105). On the other hand, if the vehicle 10 has reached the display switching point (step S104-Yes), the presentation processing unit 33 presents the second driving plan to the driver via the notification device (step S106).

[0072] The control unit 34 of the processor 23 determines whether the vehicle 10 has reached the control switching point (step S107). If the vehicle 10 has not reached the control switching point (step S107-No), the control unit 34 controls the vehicle 10 so that it travels according to the first driving plan (step S108). On the other hand, if the vehicle 10 has reached the control switching point (step S107-Yes), the control unit 34 controls the vehicle 10 so that it travels according to the second driving plan (step S109). After step S108 or step S109, the processor 23 terminates the vehicle control process.

[0073] As explained above, this vehicle control system detects discrepancies in the road information represented on each of the two maps, where the information about the road the vehicle is traveling on diverges from each other. The vehicle control system also formulates a driving plan for the section beyond the control switch point, including the discrepancy, before the vehicle 10 reaches the start point of the discrepancy or a control switch point set closer to the vehicle than the start point. Therefore, even if a discrepancy exists ahead of the vehicle, the vehicle control system can set the driving plan at an appropriate time so that the driving plan is not suddenly changed. Thus, the vehicle control system can eliminate the driver's discomfort caused by sudden changes in the driving plan.

[0074] In a modified version, the map server may detect the deviation section by performing a process similar to that performed by the deviation section detection unit 31. In this case, when the map server distributes the first map and the second map to the vehicle 10, it may also distribute deviation section information that identifies the deviation sections included within the areas represented by the first map and the second map. In this case, the storage device 5 also stores the deviation section information received via the wireless communication terminal 4. The deviation section detection unit 31 then refers to the deviation section information to identify the deviation section that exists within a predetermined distance from the vehicle 10's current position along the direction of travel of the vehicle 10. According to this modified version, the computational load on the ECU 6's processor 23 is reduced.

[0075] The computer program that realizes the functions of the processor 23 of the ECU 6 according to the above embodiment or modification may be provided in the form of being recorded on a computer-readable portable recording medium such as semiconductor memory, magnetic recording medium, or optical recording medium.

[0076] As described above, those skilled in the art can make various modifications within the scope of the present invention to suit the implemented form. [Explanation of symbols]

[0077] 1. Vehicle control system 10 vehicles 2 cameras 3 GPS receivers 4 Wireless communication terminals 5. Storage devices 6. Electronic Control Unit (ECU) 21 Communication Interface 22 memory 23 processors 31. Discrepancy interval detection unit 32. Operation Planning Department 33 Presentation Processing Unit 34 Control Unit

Claims

1. A storage unit that stores a first map and a second map representing information about roads, A discrepancy section detection unit detects a discrepancy section in which the road information shown on the first map and the road information shown on the second map diverge from each other in the direction of travel of the vehicle. A driving plan formulation unit formulates a first driving plan based on the first map for a first section from the current position of the vehicle to the starting point of the divergence section on the vehicle side or a control switching point set closer to the vehicle than the starting point, and before the vehicle reaches the control switching point, a second driving plan based on the second map for a second section including the divergence section beyond the control switching point, A control unit controls the vehicle so that it travels in the first section according to the first driving plan, and controls the vehicle so that it travels in the second section according to the second driving plan, It has, A vehicle control device wherein the accuracy of the road information represented on the first map is higher than the accuracy of the road information represented on the second map, and the update frequency of the second map is higher than the update frequency of the first map.

2. The vehicle control device according to claim 1, wherein the deviation section detection unit detects the deviation section such that the distance between the position of a predetermined feature on or around the road shown on the first map and the position of the predetermined feature shown on the second map is greater than or equal to a predetermined threshold, or the presence or absence of the predetermined feature differs between the first map and the second map.

3. A discrepancy section is detected in which the road information shown on the first map and the road information shown on the second map diverge from each other in the direction of travel of the vehicle. A first driving plan is formulated based on the first map for a first section from the current position of the vehicle to the starting point of the deviation section on the vehicle side, or a control switching point set to be closer to the vehicle than the starting point. Before the vehicle reaches the control switching point, a second driving plan is formulated for the second section, including the divergence section beyond the control switching point, based on the second map. Control the vehicle so that it travels in the first section according to the first driving plan. Control the vehicle so that it travels in the second section according to the second driving plan. This includes, A vehicle control method wherein the accuracy of the road information represented on the first map is higher than the accuracy of the road information represented on the second map, and the update frequency of the second map is higher than the update frequency of the first map.

4. A discrepancy section is detected in which the road information shown on the first map and the road information shown on the second map diverge from each other in the direction of travel of the vehicle. A first driving plan is formulated based on the first map for a first section from the current position of the vehicle to the starting point of the deviation section on the vehicle side, or a control switching point set to be closer to the vehicle than the starting point. Before the vehicle reaches the control switching point, a second driving plan is formulated for the second section, including the divergence section beyond the control switching point, based on the second map. Control the vehicle so that it travels in the first section according to the first driving plan. Control the vehicle so that it travels in the second section according to the second driving plan. The processor installed in the vehicle is made to perform this action. A computer program for vehicle control, wherein the accuracy of the road information represented on the first map is higher than the accuracy of the road information represented on the second map, and the update frequency of the second map is higher than the update frequency of the first map.

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