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

Abstract

To provide a vehicle control device which can perform a pulse and gride travel of an own vehicle without giving uneasiness to a driver of a preceding vehicle.SOLUTION: A vehicle control device comprises: a determination part 31 which determines whether the degree of visibility around an own vehicle 10 or the degree of rear visibility of a preceding vehicle that precedes the own vehicle 10 satisfies a prescribed decrease condition or not; a travel control part 33 which performs a pulse and gride travel of the own vehicle 10 so that acceleration travel and inertia travel are repeated in a prescribed vehicle speed range or in a variation range of a vehicular gap between the own vehicle 10 and the preceding vehicle; and a setting part 32 which sets at least one of the vehicle speed range, target acceleration at the time of the acceleration travel, the variation range of the vehicular gap, and a minimum vehicular gap between the own vehicle 10 and the preceding vehicle at the time of changeover from the acceleration travel to the inertial travel to change at least one of them.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] It is known that fuel consumption can be reduced by a vehicle performing intermittent driving (also called pulse-and-glide driving), which involves repeating acceleration and coasting within a predetermined vehicle speed range. A technology has been proposed that prevents a vehicle from causing a nuisance to the surrounding environment by performing such intermittent driving (see Patent Document 1).

[0003] In the proposed technology, when another vehicle or a pedestrian is detected around the host vehicle, the vehicle cruise control device narrows a predetermined speed range in which the vehicle alternates between accelerating by driving the engine and decelerating by stopping the engine. In particular, the vehicle cruise control device changes the predetermined speed range so that the predetermined speed range is narrowed as the inter-vehicle distance between the host vehicle and at least one of the preceding vehicle and the following vehicle becomes smaller. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-167794 Summary of the Invention [Problem to be solved by the invention]

[0005] Although the above technology reduces inconvenience to drivers of other vehicles traveling around the vehicle, there is a risk that the vehicle's ability to perform pulse-and-glide driving may be excessively restricted.

[0006] Therefore, an object of the present invention is to provide a vehicle control device that can make the vehicle travel in pulse-and-glide mode without making the driver of the leading vehicle feel uneasy. [Means for solving the problem]

[0007] A vehicle control device according to one embodiment has a determination unit that determines whether the degree of visibility around the host vehicle or the degree of rear visibility of a preceding vehicle ahead of the host vehicle satisfies a predetermined deterioration condition; a driving control unit that performs pulse-and-glide driving control of the host vehicle so that acceleration driving and coasting are repeated within a predetermined vehicle speed range or a change range of the inter-vehicle distance between the host vehicle and the preceding vehicle; and a setting unit that sets at least one of the vehicle speed range, target acceleration during acceleration driving, change range of the inter-vehicle distance, and minimum inter-vehicle distance between the host vehicle and the preceding vehicle when switching from acceleration driving to coasting, so as to change at least one of these depending on whether the deterioration condition is satisfied.

[0008] In one embodiment, the setting unit sets at least one of the vehicle speed range, the target acceleration during accelerating driving, and the range of change in the inter-vehicle distance when the lowering condition is not satisfied to a value smaller than at least one of these when the lowering condition is satisfied.

[0009] In one embodiment, the setting unit sets the minimum inter-vehicle distance when the reduction condition is not satisfied to be greater than the minimum inter-vehicle distance when the reduction condition is satisfied.

[0010] In one embodiment, the setting unit determines whether the reduction condition is satisfied by inputting an external sensor signal representing the area ahead of the host vehicle, which is generated by an external sensor mounted on the host vehicle, into a classifier that has been trained in advance to determine whether the degree of rear visibility of the leading vehicle satisfies the reduction condition.

[0011] A vehicle control method according to another embodiment includes determining whether the degree of visibility around the host vehicle or the degree of rear visibility of a preceding vehicle ahead of the host vehicle satisfies a predetermined deterioration condition, performing pulse-and-glide driving control of the host vehicle so as to repeat acceleration driving and coasting within a predetermined vehicle speed range or a range of change in the inter-vehicle distance between the host vehicle and the preceding vehicle, and setting at least one of the vehicle speed range, target acceleration during acceleration driving, range of change in the inter-vehicle distance, and minimum inter-vehicle distance between the host vehicle and the preceding vehicle when switching from acceleration driving to coasting so as to change at least one of these depending on whether the deterioration condition is satisfied.

[0012] In yet another embodiment, a computer program for vehicle control includes instructions to cause a processor mounted on the host vehicle to determine whether the degree of visibility around the host vehicle or the degree of rear visibility of a preceding vehicle ahead of the host vehicle satisfies a predetermined deterioration condition, perform pulse-and-glide driving control of the host vehicle so that acceleration driving and coasting are repeated within a predetermined vehicle speed range or a change range of the inter-vehicle distance between the host vehicle and the preceding vehicle, and set at least one of the vehicle speed range, target acceleration during acceleration driving, change range of the inter-vehicle distance, and minimum inter-vehicle distance between the host vehicle and the preceding vehicle when switching from acceleration driving to coasting, so as to change at least one of these depending on whether the deterioration condition is satisfied. [Effects of the Invention]

[0013] The vehicle control device according to the present disclosure has the effect of being able to cause the host vehicle to pulse-and-glide traveling without making the driver of the leading vehicle feel uneasy. [Brief explanation of the drawings]

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

[0015] A vehicle control device, a vehicle control method executed on the vehicle control device, and a computer program for vehicle control will be described below with reference to the drawings. This vehicle control device performs pulse-and-glide driving control of the host vehicle so that acceleration driving and coasting are repeated within a predetermined vehicle speed range or within a range of change in the inter-vehicle distance between the host vehicle and a preceding vehicle. In particular, this vehicle control device determines whether the degree of visibility around the host vehicle or the degree of rear visibility of a preceding vehicle ahead of the host vehicle satisfies a predetermined reduction condition related to visibility. Then, depending on whether the reduction condition is satisfied, this vehicle control device changes at least one of the vehicle speed range when performing pulse-and-glide driving control of the host vehicle, the target acceleration during acceleration driving, the range of change in the inter-vehicle distance between the host vehicle and the preceding vehicle, and the minimum inter-vehicle distance between the host vehicle and the preceding vehicle when switching from acceleration driving to coasting. Hereinafter, pulse-and-glide driving will be referred to as: PG Pulse and glide driving control is also called PG This is called cruise control.

[0016] 1 is a schematic diagram of a vehicle in which an electronic control device, which is an example of a vehicle control device, is implemented. In this embodiment, a vehicle 10 is an example of a host vehicle, and is a vehicle that includes a motor as a power source in a powertrain 11, such as a battery electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. PG This is preferable from the viewpoint of improving fuel efficiency through driving control. However, the vehicle 10 may be a vehicle in which only a power source other than a motor, such as an engine, is included in the powertrain 11. The vehicle 10 has a vehicle speed sensor 12, an external sensor 13, a GPS receiver 14, a wireless communication terminal 15, and an electronic control unit (ECU) 16.

[0017] The vehicle speed sensor 12 measures the speed of the vehicle 10 , generates a speed signal representing the speed of the vehicle 10 , and outputs the speed signal to the ECU 16 .

[0018] The exterior sensor 13 is a sensor that generates an exterior sensor signal that indicates the situation around the vehicle 10, and is a camera that is provided so as to be able to capture an image of a predetermined area around the vehicle 10 (for example, an area in front of the vehicle 10), or a distance measurement sensor such as a LiDAR or a radar. The vehicle 10 may be provided with a plurality of exterior sensors 13 with different detectable ranges or types. Each time the exterior sensor 13 generates an exterior sensor signal, the exterior sensor 13 outputs the generated exterior sensor signal to the ECU 16.

[0019] The GPS receiver 14 determines the position of the vehicle 10 based on the GPS signals received from GPS satellites at predetermined intervals, and outputs positioning information indicating the positioning results to the ECU 16. Note that the vehicle 10 may have a receiver, instead of a GPS receiver, that receives positioning signals from satellites of another satellite positioning system to determine the position of the vehicle 10.

[0020] The wireless communication terminal 15 is an example of a communication device, and is a device that executes wireless communication processing in accordance with a predetermined wireless communication standard, and by accessing, for example, a wireless base station (not shown), it is connected to an external device (for example, a server that distributes weather information) via the wireless base station and a communication network. The wireless communication terminal 15 receives downlink wireless signals containing various information such as weather information from the external device via the wireless base station, and outputs the various information contained in the downlink wireless signals to the ECU 16 via the in-vehicle network.

[0021] The ECU 16 is an example of a vehicle control device, and is capable of executing driving assistance processes including automatic driving control processes or speed control, such as adaptive cruise control (ACC), that automatically controls the vehicle speed of the vehicle 10, as examples of vehicle control processes for the vehicle 10. The ECU 16 is capable of executing PG driving control while the automatic driving control or vehicle speed control is being applied to the vehicle 10.

[0022] The ECU 16 has a communication interface 21, a memory 22, and a processor 23. The communication interface 21, the memory 22, and the processor 23 may be configured as separate circuits, or may be integrated into a single integrated circuit.

[0023] The communication interface 21 has an interface circuit for connecting the ECU 16 to other devices. The communication interface 21 passes signals from the vehicle speed sensor 12, the outside sensor 13, and the GPS receiver 14, as well as information received from the wireless communication terminal 15, to the processor 23. Furthermore, the communication interface 21 outputs a control signal for the powertrain 11 received from the processor 23 to the powertrain 11.

[0024] The memory 22 is an example of a storage unit and includes a volatile semiconductor memory and a non-volatile semiconductor memory. The memory 22 stores various data used in the vehicle control process executed by the processor 23 or generated during the vehicle control process.

[0025] The processor 23 includes one or more central processing units (CPUs) and their peripheral circuits. The processor 23 may further include other arithmetic circuits such as a logic unit, a numerical calculation unit, or a graphics processing unit. The processor 23 executes vehicle control processing.

[0026] 2 is a functional block diagram of the processor 23 related to vehicle control processing. The processor 23 has a determination unit 31, a setting unit 32, and a driving control unit 33. Each of these units in the processor 23 is, for example, a functional module realized by a computer program running on the processor 23. Alternatively, each of these units may be a dedicated arithmetic circuit provided in the processor 23.

[0027] The determination unit 31 determines whether the degree of visibility around the vehicle 10 or the degree of rear visibility of a leading vehicle ahead of the vehicle 10 satisfies a predetermined deterioration condition related to visibility (hereinafter simply referred to as the deterioration condition).

[0028] The determination unit 31 determines the degree of visibility around the vehicle 10 based on the environment around the vehicle 10, for example, the weather around the vehicle 10. That is, when the weather around the vehicle 10 is raining, snowing, or foggy, the determination unit 31 determines that the reduction condition is satisfied. To make such a determination, the determination unit 31 refers to weather information received by the ECU 16 via the wireless communication terminal 15 mounted on the vehicle 10 from a server (not shown) that distributes weather information. The determination unit 31 then determines that the reduction condition is satisfied when the latest position of the vehicle 10, determined by the GPS receiver 14, is included in the area of ​​rain, snow, or fog indicated by the weather information.

[0029] Alternatively, the determination unit 31 determines that the reduction condition is satisfied when the amount of rain measured by a rainfall sensor (not shown) mounted on the vehicle 10 is equal to or greater than a threshold value that indicates that the amount of rain is so great that the visibility around the vehicle 10 is reduced. Furthermore, the determination unit 31 may determine that the reduction condition is satisfied when the wiper operation mode of the vehicle 10 is a mode in which the wipers operate continuously.

[0030] Alternatively, if the vehicle 10 is equipped with a camera as the exterior sensor 13 for capturing an image of a predetermined area around the vehicle 10, the determination unit 31 may determine whether the lowering condition is satisfied based on an image generated by the camera. In this case, the determination unit 31 inputs the image generated by the camera to a classifier that has been trained in advance to output a determination result as to whether the lowering condition is satisfied based on the input image representing the surroundings of the vehicle 10. Such a classifier may be configured, for example, by a deep neural network (DNN) having a convolutional neural network (CNN)-type architecture. In this case, the classifier may have, for example, from the input side, multiple convolutional layers, one or more fully connected layers, and an output layer. The output layer may, for example, perform a softmax operation on the output from the fully connected layer to calculate the confidence that the lowering condition is satisfied and the confidence that the lowering condition is not satisfied. If the confidence that the lowering condition is satisfied is higher than the confidence that the lowering condition is not satisfied and is equal to or greater than a predetermined threshold, the determination unit 31 determines that the lowering condition is satisfied.

[0031] Such a classifier is trained in advance according to a predetermined learning method such as backpropagation using a large number of training images, including a plurality of images representing the situation around the vehicle 10 when the degradation condition is satisfied (e.g., images during rainfall, snowfall, or fog) and a plurality of images representing the situation around the vehicle 10 when the degradation condition is not satisfied (e.g., images during clear weather).

[0032] The classifier may be configured based on a machine learning method other than DNN, for example, a support vector machine.

[0033] Furthermore, when a preceding vehicle exists, the determination unit 31 determines whether the preceding vehicle has poor rear visibility, and if the preceding vehicle has poor rear visibility, determines that the reduction condition is satisfied. Vehicles with poor rear visibility are, for example, large vehicles such as trucks and buses, or towing vehicles, whose drivers can only see what is behind them using side mirrors. On the other hand, vehicles with good rear visibility are, for example, ordinary passenger cars, whose drivers can see what is behind them using a rearview mirror.

[0034] To determine whether the deterioration condition is satisfied based on the rear visibility of the leading vehicle, the determination unit 31 first detects the leading vehicle and identifies the vehicle type. To this end, the determination unit 31 inputs the exterior sensor signal representing the area ahead of the vehicle 10, generated by the exterior sensor 13, into a classifier pre-trained to detect other vehicles traveling around the vehicle 10 from the exterior sensor signal and identify the type of the other vehicles. This classifier detects other vehicles and identifies their vehicle types. Examples of such classifiers include CNNs for object detection, such as YOLO and Single Shot Multibox Detector, or DNNs with an attention mechanism, such as Vision Transformer. Alternatively, the classifier may be configured based on a machine learning method other than DNN, such as a support vector machine or adaBoost. The classifier is pre-trained according to a predetermined learning method using a large amount of training data representing various vehicle types to be detected. If the exterior sensor 13 is a ranging sensor and the exterior sensor signal is a ranging signal, the classifier may only detect other vehicles. In this case, the determination unit 31 may estimate the size of the detected other vehicle based on the range of directions in which the other vehicle detected on the ranging signal is represented and the distance measurement value for that direction, and identify the type of the other vehicle based on the estimated size.

[0035] When another vehicle is detected, the determination unit 31 determines whether the detected other vehicle is a preceding vehicle. If the external sensor signal is a ranging signal generated by a ranging sensor, the determination unit 31 compares the direction indicated by the detected other vehicle in the ranging signal with a forward range corresponding to the area ahead of the vehicle 10. If the direction indicated by the detected other vehicle is included in the forward range, the determination unit 31 determines that the other vehicle is a preceding vehicle. On the other hand, if the direction indicated by the detected other vehicle is outside the forward range, the determination unit 31 determines that the other vehicle is not a preceding vehicle.

[0036] Furthermore, when the external sensor signal is an image generated by a camera, the determination unit 31 identifies an own lane area on the image that corresponds to the own lane in which the vehicle 10 is traveling. If the lower end of the object area in which the detected other vehicle is depicted is included in the own lane area, the determination unit 31 determines that the other vehicle is a preceding vehicle. On the other hand, if the lower end of the object area is outside the own lane area, the determination unit 31 determines that the other vehicle depicted in the object area is not a preceding vehicle.

[0037] To identify the vehicle's own lane area, the determination unit 31 detects lane markings from the image. The determination unit 31 detects lane markings by inputting the image into a classifier that has been trained in advance to detect lane markings. In this case, a classifier for detecting other vehicles may be trained in advance to also detect lane markings, or a DNN for semantic segmentation, such as a U-Net, may be used as the classifier for detecting lane markings. Alternatively, the determination unit 31 may detect edges with varying brightness for each horizontal line in the image and detect a combination of edges separated by a distance equivalent to the lane width as the edge of a lane marking. The determination unit 31 determines the region between the two detected lane markings closest to the vehicle 10 as the vehicle's own lane area.

[0038] If the detected other vehicle is a preceding vehicle, the determination unit 31 determines whether the type of the other vehicle corresponds to a vehicle type with poor rear visibility. If the type of the other vehicle corresponds to a vehicle type with poor rear visibility, the determination unit 31 determines that the reduction condition is satisfied. Note that if both a camera and a distance measurement sensor are provided as the external sensor 13, the determination unit 31 may determine whether there is a preceding vehicle and whether the rear visibility of the preceding vehicle satisfies the reduction condition by performing the above processing on both the image from the camera and the distance measurement signal from the distance measurement sensor. In this case, if the preceding vehicle is determined to be a vehicle with poor rear visibility based on either the image or the distance measurement sensor, the determination unit 31 may determine that the reduction condition is satisfied.

[0039] When the determination unit 31 determines that the degradation condition is satisfied according to any of the above-mentioned criteria, it notifies the setting unit 32 of the determination result indicating that fact. On the other hand, when the determination unit 31 does not determine that the degradation condition is satisfied according to any of the criteria, it determines that the degradation condition is not satisfied and notifies the setting unit 32 of the determination result.

[0040] Note that if the inter-vehicle distance between vehicle 10 and the preceding vehicle is greater than a predetermined distance (for example, several hundred meters), the behavior of vehicle 10 does not affect the driver of the preceding vehicle, and therefore, determination unit 31 may determine that the reduction condition is satisfied. Similarly, determination unit 31 may determine that the reduction condition is satisfied even when no preceding vehicle is detected. In these cases, determination unit 31 may notify setting unit 32 of the determination result that the reduction condition is satisfied.

[0041] When a leading vehicle is detected from an image generated by a camera, which is an example of the external sensor 13, the position of the bottom edge of the object area in which the leading vehicle is depicted in the image is assumed to correspond to the position where the leading vehicle touches the road surface. Furthermore, the position in the image corresponds one-to-one with the orientation as seen from the camera. Therefore, the determination unit 31 may estimate the distance between the vehicle 10 and the leading vehicle based on parameters such as the mounting position, shooting direction, and angle of view of the camera, which is an example of the external sensor 13, and the position of the bottom edge of the object area in which the leading vehicle is depicted in the image. Alternatively, when a ranging sensor is mounted on the vehicle 10 as one of the external sensors 13, the determination unit 31 may use the measured value of the distance indicated by the ranging signal in the orientation in which the leading vehicle was detected as the distance between the vehicle 10 and the leading vehicle.

[0042] The setting unit 32 determines whether the lowering condition is satisfied or not by PG Parameters in driving control (hereinafter, PG That is, the setting unit 32 sets at least one of the vehicle speed range, the target acceleration during acceleration, the range of change in the inter-vehicle distance between the vehicle 10 and the preceding vehicle, and the minimum inter-vehicle distance between the vehicle 10 and the preceding vehicle when switching from acceleration to coasting, depending on the determination result of whether the lowering condition is satisfied. PG At least one vehicle is configured to change a cruise control parameter. PG Set the cruise control parameters.

[0043] When the lowering condition is satisfied, it is more difficult for the driver of the preceding vehicle to check the behavior of the vehicle 10 than when the lowering condition is not satisfied. PG Even if the vehicle 10 repeatedly approaches and moves away from the preceding vehicle due to the driving control, the driver of the preceding vehicle is unlikely to notice such behavior of the vehicle 10, and therefore the driver of the preceding vehicle is unlikely to feel uneasy about the behavior of the vehicle 10. On the other hand, if the lowering condition is not satisfied, the driver of the preceding vehicle is unlikely to feel uneasy about the behavior of the vehicle 10. PG By controlling the vehicle's speed, it is relatively easy to notice the vehicle's behavior of repeatedly approaching and moving away from the vehicle ahead. PGThe driver of the leading vehicle is likely to feel uneasy about the vehicle 10 undergoing driving control.

[0044] Therefore, the setting unit 32 sets the following when the lowering condition is not satisfied: PG The change in the behavior of the vehicle 10 or the change in the inter-vehicle distance during the driving control is made more gradual than when the lowering condition is satisfied. PG The driving control parameters are set. Specifically, the setting unit 32 determines a range of the vehicle speed of the vehicle 10 under PG driving control when the lowering condition is not satisfied (hereinafter referred to as the vehicle speed range), PG At least one of the target acceleration during acceleration travel and the range of change in the inter-vehicle distance between the vehicle 10 and the preceding vehicle (hereinafter simply referred to as the range of change in the inter-vehicle distance) is made smaller than when the reduction condition is satisfied.

[0045] For example, the setting unit 32 sets the vehicle speed range when the reduction condition is satisfied to ±5% to ±10% of the target vehicle speed, and sets the vehicle speed range when the reduction condition is not satisfied to a range obtained by multiplying the vehicle speed range when the reduction condition is satisfied by 0.4 to 0.8. The target vehicle speed may be a speed set by the driver via an operating device (not shown) provided in the cabin of the vehicle 10, or the legal speed of the road section on which the vehicle 10 is traveling. The legal speed of the road section on which the vehicle 10 is traveling is determined by referring to the position of the vehicle 10 measured by the GPS receiver 14 and map information including information on the position and legal speed of each road section. Such map information is stored in advance in the memory 22.

[0046] Alternatively, the setting unit 32 sets the target acceleration during accelerating travel when the reduction condition is satisfied to an acceleration at which the vehicle speed changes from the lower limit to the upper limit of the vehicle speed range in about 10 seconds to several tens of seconds, and sets the target acceleration when the reduction condition is not satisfied to a range obtained by multiplying the target acceleration when the reduction condition is satisfied by 0.4 to 0.8.Alternatively, the setting unit 32 sets the change range of the inter-vehicle distance when the reduction condition is satisfied to about several tens of meters to 200 meters, and sets the change range of the inter-vehicle distance when the reduction condition is not satisfied to a range obtained by multiplying the change range of the inter-vehicle distance when the reduction condition is satisfied by 0.4 to 0.8.

[0047] Alternatively, the setting unit 32 may set the minimum inter-vehicle distance between the vehicle 10 and the preceding vehicle when the reduction condition is not satisfied so that it is greater than the minimum inter-vehicle distance when the reduction condition is satisfied. For example, the setting unit 32 sets the minimum inter-vehicle distance when the reduction condition is satisfied to approximately several tens of meters to 100 meters, and sets the minimum inter-vehicle distance when the reduction condition is not satisfied to a distance obtained by multiplying the minimum inter-vehicle distance when the reduction condition is satisfied by 1.2 to 2. In this way, when the driver of the preceding vehicle can easily visually recognize the behavior of the vehicle 10 traveling behind, the vehicle 10 does not get too close to the preceding vehicle, which reduces the driver of the preceding vehicle from feeling uneasy.

[0048] The setting unit 32 PG Of the driving control parameters, parameters other than those that are changed depending on whether the lowering condition is satisfied may be set to predetermined reference values.

[0049] The setting unit 32 PG Two or more of the driving control parameters that can be applied in combination PGThe travel control parameters may be set depending on whether or not the reduction condition is satisfied. For example, the setting unit 32 may set either one of the vehicle speed range or the range of change in the inter-vehicle distance and the target acceleration during accelerating travel depending on whether or not the reduction condition is satisfied as described above, or may set either one of the vehicle speed range or the range of change in the inter-vehicle distance and the minimum inter-vehicle distance depending on whether or not the reduction condition is satisfied as described above.

[0050] The setting unit 32 sets each PG The driving control parameters are notified to the driving control unit 33.

[0051] The travel control unit 33 controls the vehicle 10 according to each of the settings made by the setting unit 32 while the vehicle 10 is under automatic driving control or speed control. PG for the vehicle 10 according to the driving control parameters PG In particular, the driving control unit 33 executes PG driving control when the vehicle 10 can continue driving at the target vehicle speed. Specifically, the driving control unit 33 executes PG driving control when the distance between the vehicle 10 and a preceding vehicle traveling ahead of the vehicle 10 in the vehicle's own lane is greater than a distance threshold at which driving at the target vehicle speed can be continued, or when there is no preceding vehicle traveling in the vehicle's own lane, and the vehicle 10 does not need to accelerate or decelerate.

[0052] Therefore, the driving control unit 33 may detect the preceding vehicle by performing the same processing as that described for the determination unit 31, or may receive the detection result of the preceding vehicle from the determination unit 31. When the preceding vehicle is detected, the driving control unit 33 may estimate the distance between the vehicle 10 and the preceding vehicle in the same manner as that described for the determination unit 31.

[0053] Furthermore, the driving control unit 33 may determine whether there is a point within a predetermined distance in the direction of travel of the vehicle 10 where acceleration or deceleration is required, based on map information, the latest position of the vehicle 10 measured by the GPS receiver 14, and the direction of travel of the vehicle 10 measured by a direction sensor (not shown) mounted on the vehicle 10. A point where deceleration is required may be, for example, a point where a stop line is installed or a point where a toll gate is installed on a motorway. If there is no such point where deceleration is required, the driving control unit 33 may determine that there is no need to decelerate the vehicle 10.

[0054] The driving control unit 33 may be configured to execute the PG driving control only when the driver has performed an operation to approve the execution of the PG driving control via an operating device provided in the vehicle cabin.

[0055] While the PG driving control is being executed, the driving control unit 33 accelerates the vehicle 10 at the target acceleration set by the setting unit 32 until the vehicle speed of the vehicle 10 reaches the upper limit of the vehicle speed range, or until the inter-vehicle distance between the vehicle 10 and the preceding vehicle reaches the lower limit of the range of change in the inter-vehicle distance (i.e., the minimum inter-vehicle distance). The driving control unit 33 may also estimate the inter-vehicle distance using a method similar to that described for the determination unit 31.

[0056] The driving control unit 33 generates a control signal for controlling the powertrain 11 so that the acceleration measured by an acceleration sensor (not shown) mounted on the vehicle 10 approaches a target acceleration. In this case, the driving control unit 33 may generate the control signal according to feedback control such as PID control. The driving control unit 33 then outputs the generated control signal to the powertrain 11.

[0057] When the vehicle speed of vehicle 10 measured by vehicle speed sensor 12 reaches the upper limit of the vehicle speed range, the inter-vehicle distance reaches the lower limit of the inter-vehicle distance change range, or the inter-vehicle distance from a preceding vehicle reaches the upper limit of the inter-vehicle distance change range, the cruise control unit 33 controls the powertrain 11 to coast the vehicle 10. That is, the cruise control unit 33 generates a control signal corresponding to the minimum value of the accelerator pedal depression and outputs the control signal to the powertrain 11. Then, when the speed of vehicle 10 measured by vehicle speed sensor 12 reaches the lower limit of the vehicle speed range, the cruise control unit 33 controls the powertrain 11 to accelerate the vehicle 10 at a predetermined target acceleration. In this way, while the PG cruise control is being applied, the cruise control unit 33 controls the powertrain 11 so that the vehicle speed of vehicle 10 is within the vehicle speed range, or the inter-vehicle distance is within the inter-vehicle distance change range, and the vehicle 10 alternates between accelerating and coasting. When a preceding vehicle is not detected or the distance to the preceding vehicle is greater than a predetermined distance (for example, several hundred meters), the travel control unit 33 determines whether the vehicle is traveling within the vehicle speed range set by the setting unit 32. PG Cruise control can be performed.

[0058] The cruise control unit 33 terminates the PG cruise control when the distance between the preceding vehicle and vehicle 10 in the own lane becomes equal to or less than a distance threshold, or when the distance from the current position of vehicle 10 to a point where deceleration is required becomes equal to or less than a predetermined distance. The distance threshold is a value smaller than the minimum inter-vehicle distance set by the setting unit 32. Alternatively, the cruise control unit 33 may terminate the PG cruise control when the driver performs an operation to terminate the PG cruise control via an operating device, or when the driver depresses the accelerator pedal or brake pedal by a predetermined amount or more.

[0059] 3(a) to 3(d) are diagrams showing examples of the relationship between the PG driving control parameters when the reduction condition is satisfied and when it is not satisfied, respectively. In FIG. 3(a) to 3(d), the horizontal axis represents elapsed time.

[0060] FIG. 3(a) shows an example in which the vehicle speed range differs depending on whether the reduction condition is satisfied. In FIG. 3(a), the vertical axis represents vehicle speed. Graph 301 represents the change in vehicle speed over time when the reduction condition is satisfied, and graph 302 represents the change in vehicle speed over time when the reduction condition is not satisfied. As shown in this example, compared to vehicle speed range R1 when the reduction condition is satisfied, vehicle speed range R2 when the reduction condition is not satisfied is narrower. Therefore, compared to when the reduction condition is satisfied, it is more difficult for the driver of the leading vehicle to notice a change in vehicle speed of vehicle 10 when the reduction condition is not satisfied.

[0061] FIG. 3(b) shows an example in which the range of change in the inter-vehicle distance between vehicle 10 and the preceding vehicle differs depending on whether the reduction condition is satisfied. In FIG. 3(b), the vertical axis represents the inter-vehicle distance. Graph 311 represents the change over time in the inter-vehicle distance when the reduction condition is satisfied, and graph 312 represents the change over time in the inter-vehicle distance when the reduction condition is not satisfied. As shown in this example, the change range D2 of the inter-vehicle distance when the reduction condition is not satisfied is narrower than the change range D1 of the inter-vehicle distance when the reduction condition is satisfied. Therefore, when the reduction condition is not satisfied, it is more difficult for the driver of the preceding vehicle to notice a change in the inter-vehicle distance from vehicle 10 than when the reduction condition is satisfied.

[0062] 3(c) shows an example in which the target acceleration during accelerating driving differs depending on whether the reduction condition is satisfied. In FIG. 3(c), the vertical axis represents vehicle speed. Graph 321 represents the change in vehicle speed over time when the reduction condition is satisfied, and graph 322 represents the change in vehicle speed over time when the reduction condition is not satisfied. As shown in this example, the vehicle speed change period P2 when the reduction condition is not satisfied is longer than the vehicle speed change period P1 when the reduction condition is satisfied. Therefore, compared to when the reduction condition is satisfied, it is more difficult for the driver of the leading vehicle to notice a change in vehicle speed of vehicle 10 when the reduction condition is not satisfied.

[0063] FIG. 3(d) shows an example in which the minimum inter-vehicle distance between vehicle 10 and the preceding vehicle differs depending on whether the reduction condition is satisfied. In FIG. 3(d), the vertical axis represents the inter-vehicle distance. Graph 331 represents the change over time in the inter-vehicle distance when the reduction condition is satisfied, and graph 332 represents the change over time in the inter-vehicle distance when the reduction condition is not satisfied. As shown in this example, the minimum inter-vehicle distance M2 when the reduction condition is not satisfied is larger than the minimum inter-vehicle distance M1 when the reduction condition is satisfied. Therefore, when the reduction condition is not satisfied, the driver of the preceding vehicle is less likely to feel pressured by the approach of vehicle 10 than when the reduction condition is satisfied.

[0064] 4 is an operational flowchart of the vehicle control process. While PG driving control is being executed, processor 23 executes the vehicle control process in accordance with this operational flowchart.

[0065] The determination unit 31 determines whether or not a condition for lowering visibility is satisfied (step S101). If the condition for lowering visibility is satisfied (step S101—Yes), the setting unit 32 PG At least one of the vehicle speed range, the target acceleration during acceleration, and the range of change in the inter-vehicle distance among the driving control parameters is set to a relatively large value, or PG Among the driving control parameters, the minimum inter-vehicle distance is set to a relatively small value (step S102). On the other hand, if the reduction condition is not satisfied (step S101-No), the setting unit 32 PG At least one of the vehicle speed range, the target acceleration during acceleration, and the range of change in the inter-vehicle distance among the driving control parameters is set to a relatively small value, or PG Among the driving control parameters, the minimum inter-vehicle distance is set to a relatively large value (step S103). After step S102 or S103, the driving control unit 33 PG for the vehicle 10 according to the driving control parameters PG Processor 23 then executes travel control (step S104), and repeats the processes from step S101 onwards.

[0066] As described above, this vehicle control device determines whether the degree of visibility around the vehicle or the degree of rear visibility of the leading vehicle satisfies the visibility reduction condition. PG In particular, the vehicle control device sets a driving control parameter when the lowering condition is not satisfied compared to when the lowering condition is satisfied. PG The driving control parameters are PG The vehicle control device is set so that the behavior of the host vehicle changes gradually while the driving control is being applied. As a result, the vehicle control device can control the host vehicle without making the driver of the preceding vehicle feel uneasy. PG It can be run.

[0067] A computer program that realizes the functions of the processor 23 of the ECU 16 according to each of the above embodiments or variations 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. [Explanation of symbols]

[0068] 10 vehicle, 11 power train, 12 vehicle speed sensor, 13 outside sensor, 14 GPS receiver, 15 wireless communication terminal, 16 electronic control unit (ECU), 21 communication interface, 22 memory, 23 processor, 31 determination unit, 32 setting unit, 33 driving control unit

Claims

1. a determination unit that determines whether a degree of visibility around the host vehicle or a degree of rear visibility of a preceding vehicle preceding the host vehicle satisfies a predetermined deterioration condition; a travel control unit that performs pulse-and-glide travel control of the host vehicle so that acceleration travel and coasting are repeated within a predetermined vehicle speed range or a range of change in the inter-vehicle distance between the host vehicle and the preceding vehicle; a setting unit that sets at least one of the vehicle speed range, the target acceleration during the accelerating traveling, the range of change of the inter-vehicle distance, and the minimum inter-vehicle distance between the host vehicle and the preceding vehicle when switching from the accelerating traveling to the coasting traveling, depending on whether the reduction condition is satisfied; A vehicle control device having the above.

2. 2. The vehicle control device according to claim 1, wherein the setting unit reduces at least one of the vehicle speed range, the target acceleration, and the range of change of the inter-vehicle distance when the lowering condition is not satisfied, compared to the at least one of the ranges when the lowering condition is satisfied.

3. The vehicle control device according to claim 1 , wherein the setting unit increases the minimum inter-vehicle distance when the reduction condition is not satisfied, compared to the minimum inter-vehicle distance when the reduction condition is satisfied.

4. 3. The vehicle control device according to claim 1, wherein the determination unit determines whether the deterioration condition is satisfied by inputting an external sensor signal, which is generated by an external sensor mounted on the vehicle and indicates an area ahead of the vehicle, into a classifier that is trained in advance to determine whether a degree of rear visibility of the leading vehicle satisfies the deterioration condition.

5. determining whether the degree of visibility around the host vehicle or the degree of rear visibility of a preceding vehicle preceding the host vehicle satisfies a predetermined deterioration condition; pulse-and-glide travel control of the host vehicle so that acceleration travel and coasting are repeated within a predetermined vehicle speed range or a range of change in the inter-vehicle distance between the host vehicle and the preceding vehicle; setting at least one of the vehicle speed range, the target acceleration during the accelerating traveling, the range of change of the inter-vehicle distance, and the minimum inter-vehicle distance between the host vehicle and the preceding vehicle when switching from the accelerating traveling to the coasting traveling, so as to change the at least one of the vehicle speed range, the target acceleration during the accelerating traveling, the range of change of the inter-vehicle distance, and the minimum inter-vehicle distance between the host vehicle and the preceding vehicle when switching from the accelerating traveling to the coasting traveling, depending on whether the decrease condition is satisfied; A vehicle control method comprising:

6. determining whether the degree of visibility around the host vehicle or the degree of rear visibility of a preceding vehicle preceding the host vehicle satisfies a predetermined deterioration condition; pulse-and-glide travel control of the host vehicle so that acceleration travel and coasting are repeated within a predetermined vehicle speed range or a range of change in the inter-vehicle distance between the host vehicle and the preceding vehicle; setting at least one of the vehicle speed range, the target acceleration during the accelerating traveling, the range of change of the inter-vehicle distance, and the minimum inter-vehicle distance between the host vehicle and the preceding vehicle when switching from the accelerating traveling to the coasting traveling, so as to change the at least one of the vehicle speed range, the target acceleration during the accelerating traveling, the range of change of the inter-vehicle distance, and the minimum inter-vehicle distance between the host vehicle and the preceding vehicle when switching from the accelerating traveling to the coasting traveling, depending on whether the decrease condition is satisfied; A computer program for vehicle control that causes a processor mounted on the vehicle to execute the above.

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