Driving control device, driving control method, and driving control program

Abstract

To provide a travelling control device configured to enable opportunities to execute a coast travelling mode from increasing.SOLUTION: When a gradient in a downhill road satisfies a predetermined condition in a cruise travelling mode, a CPU switches the mode to a coast travelling mode. When an own vehicle VC(1) is travelling in a tunnel in which vehicles travel on a one-way road, the CPU switches the mode to the coast travelling mode, even when the vehicle is travelling on a sloping road gentler than a road on which the vehicle is travelling outside the tunnel.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a travel control device, a travel control method, and a travel control program.

Background Art

[0002] For example, Patent Document 1 below describes a control device that switches to coasting during cruise control. This device determines the transition to coasting and the end of coasting according to the inter-vehicle time, which is the time required for the host vehicle to travel only by the inter-vehicle distance from the preceding vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The above coasting is effective in reducing the energy consumption rate of the vehicle. However, in the case where the vehicle is traveling downhill, the above device cannot necessarily sufficiently reduce the energy consumption rate.

Means for Solving the Problems

[0005] Hereinafter, means for solving the above problems and their effects will be described. 1. The following processes are executed: coasting, cruising, gradient information acquisition (S72, S72a), deviation variable acquisition (S74, S74a, S86), and switching (S62). The coasting process is a process that causes the vehicle to coast; the cruising process is a process that controls the speed of the vehicle to a set speed while prioritizing the fulfillment of predetermined conditions; the predetermined conditions are conditions that maintain the distance to the preceding vehicle within a predetermined range when a preceding vehicle exists within a predetermined range in front of the vehicle; and the gradient information acquisition process acquires gradient information of the road surface on which the vehicle is traveling. The operation is a driving control device that includes a process, the deviation variable acquisition process being a process to acquire a deviation variable which is a variable that determines the acceleration generated in the vehicle when the vehicle is traveling down a slope having a predetermined gradient by coasting operation, separately from the gradient information, and the switching process being a process that takes the gradient information and the deviation variable as input and switches to coasting operation when the vehicle is traveling down a slope while cruising operation is being performed, and also includes a process that switches to coasting operation when the magnitude of the gradient differs depending on the value of the deviation variable.

[0006] While the acceleration of a vehicle coasting downhill depends on the road surface gradient, the variables influencing this acceleration are not limited to the road surface gradient. Therefore, when switching to coasting based solely on gradient information, the condition for switching is that the vehicle speed and distance between vehicles can be controlled within an appropriate range, regardless of the influence of other variables. This can lead to a decrease in the frequency of switching to coasting. In the above configuration, however, the decision of whether or not to switch to coasting is made not only based on the road surface gradient information but also on the value of the deviation variable. As a result, it is possible to increase the opportunities to switch to coasting as much as possible while controlling the vehicle speed and distance between vehicles within an appropriate range. [Brief explanation of the drawing]

[0007] [Figure 1] This is a diagram showing the configuration of a driving control system according to one embodiment. [Figure 2] This is a flowchart showing the procedure of processing performed by the control device according to the said embodiment. [Figure 3] This is a flowchart showing the procedure of processing performed by the control device according to the said embodiment. [Figure 4] This is a flowchart showing the procedure of processing performed by the control device according to the said embodiment. [Figure 5] Figures (a) and (b) show whether or not there is a switch depending on whether or not the tunnel is one-way. [Figure 6] This is a flowchart showing the procedure of processing performed by the control device according to the second embodiment. [Figure 7] This is a flowchart showing the procedure of processing performed by the control device according to the third embodiment. [Modes for carrying out the invention]

[0008] <First Embodiment> The first embodiment will be described below with reference to the drawings. Figure 1 shows the device mounted on the vehicle in this embodiment. As shown in Figure 1, the optical sensor 10 emits laser light, such as near-infrared light. The optical sensor 10 also generates distance point data based on receiving reflected laser light. The distance point data includes a distance variable, which is a variable indicating the distance between the object that reflected the laser light and the vehicle; a direction variable, which is a variable indicating the direction of irradiation of the laser light; and an intensity variable, which is a variable indicating the reflection intensity of the reflected object. This can be achieved, for example, by the TOF (Time of Flight) method. However, the distance point data may be generated using the FMCW (Frequency Modulated Continuous Wave) method, not limited to the TOF method. In that case, the distance point data can include a velocity variable, which is a variable indicating the relative velocity with respect to the object that reflected the laser light.

[0009] The optical sensor 10 periodically scans the direction of laser beam irradiation in the horizontal and vertical directions and outputs distance measurement point cloud data Drpc, which is a collection of distance measurement point data obtained. LIDARECU12 performs object recognition based on the distance measurement point cloud data Drpc. The recognition process can be performed, for example, according to the following steps: First, clustering is performed on the distance measurement point cloud data Drpc. Next, feature quantities are extracted from the set of distance measurement point data identified as a single object by the clustering process. Then, the extracted feature quantities are input into an identification model that determines whether or not it is a predetermined object. Alternatively, instead of the process involving these steps, the distance measurement point cloud data Drpc may be directly input into a deep learning model to recognize objects.

[0010] Camera 20 outputs image data Dpo from outside the vehicle VC. Image ECU 22 performs object recognition processing around the vehicle based on the image data Dpo, which is data related to the image captured by camera 20.

[0011] ADASECU30 executes processes to control the driving of the vehicle VC. When ADASECU30 executes processes to control driving, it receives recognition results from LIDARECU12 and image ECU22 via the local network 40. ADASECU30 also executes cruise control, etc., in response to input operations to the cruise control interface 50. The cruise control interface 50 is an interface that allows input operations such as instructions on whether or not to execute cruise control and instructions on the set vehicle speed SPD* in the cruise driving process. When ADASECU30 executes processes to control driving, it operates the drive system 60, braking system 62, and steering system 64.

[0012] The drive system 60 includes at least one of two devices that generate thrust for the vehicle: an internal combustion engine and a rotating electric machine. The drive system 60 may also include a drive control device that controls the internal combustion engine and the rotating electric machine. In that case, "ADASECU 30 operates the drive system 60" means that ADASECU 30 outputs a command signal to the drive control device.

[0013] The braking system 62 includes at least one of two devices: one that slows down the rotation of the wheels by frictional force, and another that slows down the rotation of the wheels by converting the power of the wheels into electrical energy. The device that slows down the rotation of the wheels by converting power into electrical energy may be shared with the rotating electric machine of the drive system. The braking system 62 may also include a braking control device that controls the device that slows down the rotation of the wheels. In that case, "ADASECU 30 operates the braking system 62" means that ADASECU 30 outputs a command signal to the braking control device.

[0014] The steering system 64 includes a steering actuator that steers the steering wheels. The steering system 64 may also include a steering control device that operates the steering actuator. In that case, "ADASECU 30 operates the steering system 64" means that ADASECU 30 outputs a command signal to the steering control device.

[0015] ADASECU30 refers to the vehicle speed SPD detected by the vehicle speed sensor 70 and the longitudinal acceleration Gx of the vehicle VC detected by the acceleration sensor 72. ADASECU30 also refers to the accelerator operation amount ACCP, which is the amount of accelerator pedal depression detected by the accelerator sensor 74, and the brake operation amount Brk, which is the amount of brake pedal depression detected by the brake sensor 76. ADASECU30 also refers to the Global Positioning System (GPS78) location data Dgps and map data 80. ADASECU30 also refers to the output signals Ssb(1) to Ssb(5) of the seat belt switch 82. Output signals Ssb(1) to Ssb(5) are turned on when the corresponding seat belt of one of the five seats is fastened, and turned off when it is released.

[0016] Specifically, the ADASECU 30 includes a CPU 32, a storage device 34, and a peripheral circuit 36. Here, the peripheral circuit 36 includes a circuit that generates a clock signal for defining internal operations, a power supply circuit, a reset circuit, and the like. The ADASECU 30 executes cruise driving processing and the like by the CPU 32 executing the driving control program 34a stored in the storage device 34.

[0017] In the present embodiment, when cruise control is instructed by an input operation to the cruise system interface 50, the CPU 32 executes cruise driving processing or coasting driving processing. The cruise driving processing is processing for controlling the vehicle speed SPD to the set vehicle speed SPD*. However, when there is a preceding vehicle within the defined range of the lane in which the host vehicle is traveling, the CPU 32 prioritizes control to maintain the inter-vehicle distance from the preceding vehicle within a predetermined range. Further, when there is no preceding vehicle within a predetermined range of the lane in which the host vehicle is traveling, etc., the CPU 32 executes coasting driving processing within a range where the difference between the vehicle speed SPD and the set vehicle speed SPD* is within a predetermined value or less. Incidentally, the CPU 32 recognizes the preceding vehicle based on the recognition results by each of the LIDARECU 12 and the image ECU 22.

[0018] The coasting driving processing is processing for not applying power from the vehicle's thrust generation device to the drive wheels. For example, when the drive system 60 includes an internal combustion engine as a thrust generation device and a transmission, the coasting driving processing may be processing for setting the neutral state in which the power transmission between the internal combustion engine and the drive wheels is interrupted. Also, for example, when the drive system 60 includes a rotary electric machine as a thrust generation device, the coasting driving processing may be processing for setting the torque command value of the rotary electric machine to zero. Note that when the drive system 60 includes an internal combustion engine as a thrust generation device and a rotary electric machine, etc., it is not essential for the thrust generation device not to generate power in the coasting driving processing. That is, in that case, for example, a process in which the ratio of the driving force of the internal combustion engine transmitted to the drive wheels becomes zero by converting the driving force of the internal combustion engine into the generated electric power of the rotary electric machine may be used.

[0019] The processes executed by ADASECU30 will be described in the order of "Process for determining whether to execute cruise control" and "Process for switching between cruise driving process and coasting driving process".

[0020] "Process for determining whether to execute cruise control" Fig. 2 shows the procedure of the process for determining whether to execute cruise control. The process shown in Fig. 2 is realized by the CPU 32 repeatedly executing the driving control program 34a, for example, at a predetermined cycle. In the following, the step numbers of each process are represented by numbers preceded by "S".

[0021] In the series of processes shown in Fig. 2, the CPU 32 first determines whether the ACC selection switch among the cruise system interfaces 50 is in the ON state (S10). The ACC selection switch is a switch that is turned on when cruise control is instructed. When the CPU 32 determines that it is in the ON state (S10: YES), it determines whether the cruise control flag Facc is "1" (S12). The cruise control flag Facc becomes "1" when either the cruise driving process or the coasting driving process is being executed, and becomes "0" when neither is being executed. When the CPU 32 determines that the cruise control flag Facc is "0" (S12: NO), it determines whether neither the accelerator pedal nor the brake pedal has been operated (S18). This process is to determine whether the execution conditions for cruise control are satisfied. That is, in this embodiment, the logical product of the ACC selection switch being in the ON state and there being no override by the driver is defined as the execution condition for cruise control. Here, an override is either the accelerator pedal being operated or the brake pedal being operated. When the CPU 32 determines that neither has been operated (S18: YES), it assigns "1" to the cruise control flag Facc (S20).

[0022] On the other hand, if the CPU 32 determines that the cruise control flag Facc is "1" (S12:YES), it determines whether the logical OR of the operation of the accelerator pedal and the operation of the brake pedal is true (S14). This process determines whether an override occurred while cruise control was being executed. If the CPU 32 determines that the logical OR is true (S14:YES), it assigns "0" to the cruise control flag Facc (S16).

[0023] Furthermore, when CPU32 completes processing S16 and S20, or when it makes a negative determination in processing S10, S14, and S18, it temporarily terminates the series of processes shown in Figure 2. "Processing related to switching between cruising and coasting." Figure 3 shows the procedure for switching based on the distance between vehicles, etc. The process shown in Figure 3 is realized by the CPU 32 repeatedly executing the driving control program 34a at a predetermined cycle, for example.

[0024] In the series of processes shown in Figure 3, the CPU 32 first determines whether the cruise control flag Facc is "1" (S30). If the CPU 32 determines that the cruise control flag Facc is "1" (S30: YES), it determines whether the vehicle is in coasting mode (S32). If the CPU 32 determines that the vehicle is in coasting mode (S32: YES), it determines whether the interval time is less than the threshold t1 (S34). The interval time is the time required for the vehicle to reach the current position of the preceding vehicle in the lane in which the vehicle is traveling. The interval time is calculated by the CPU 32 based on the vehicle speed SPD. This process determines whether braking force should be applied to the vehicle in order to drive the vehicle safely when a preceding vehicle is present. The threshold t1 is set to an interval time short enough that braking force should be applied to the vehicle.

[0025] If the CPU 32 determines that the threshold t1 is greater than or equal to (S34: NO), it determines whether the vehicle speed SPD is less than or equal to the set vehicle speed SPD* plus a predetermined amount α (S36). The predetermined amount α is the upper limit of the amount by which the vehicle speed SPD exceeds the set vehicle speed SPD* when controlling the vehicle speed SPD according to the set vehicle speed SPD*. If the CPU 32 determines that the vehicle speed SPD is less than or equal to the amount by which the predetermined amount α is added (S36: YES), it determines whether the vehicle speed SPD is greater than or equal to the amount obtained by subtracting a predetermined amount β from the set vehicle speed SPD* (S38). The predetermined amount β is the lower limit of the amount by which the vehicle speed SPD falls below the set vehicle speed SPD* when controlling the vehicle speed SPD according to the set vehicle speed SPD*.

[0026] If CPU32 determines that the value is less than the value obtained by subtracting a predetermined amount β (S38: NO), it determines whether the interval time is greater than or equal to the threshold t4 (S44). This process determines whether the distance to the preceding vehicle is excessively large. The threshold t4 is set to a value greater than the threshold t1. The preceding vehicle here refers to the vehicle targeted by the cruise control process. That is, it refers to vehicles located within a specified range in front of the vehicle in the lane in which the vehicle is traveling. Therefore, vehicles located far beyond the specified range are not included. If there is no preceding vehicle within the specified range, CPU32 makes a negative determination in the S44 process.

[0027] The CPU 32 switches to cruise mode (S42) when it makes a positive determination in processing S34 and S44, and when it makes a negative determination in processing S36. That is, in coasting mode, the CPU 32 switches to cruise mode when any of the following conditions are met.

[0028] Condition (A): The condition is that the interval between vehicles is less than the threshold t1. Condition (B): This condition means that the amount by which the vehicle speed SPD exceeds the set vehicle speed SPD* exceeds a predetermined amount α.

[0029] Condition (C): This condition states that the logical AND of the following two conditions is true: the amount by which the vehicle speed SPD falls below the set vehicle speed SPD* exceeds a predetermined amount β, and the interval between vehicles is greater than or equal to the threshold t4. On the other hand, if the CPU 32 determines that it is in cruise driving mode (S32: NO), it determines whether the braking force is greater than zero (S46). If the CPU 32 determines that it is greater than zero (S46: YES), it determines whether the interval between vehicles is greater than or equal to threshold t2 (S48). Threshold t2 is set to a value greater than threshold t1 but less than threshold t4. This process determines whether it is permissible to ease the braking force of the vehicle and coast. If the CPU 32 determines that it is greater than or equal to threshold t2 (S48: YES), it determines whether the vehicle speed SPD is greater than or equal to the value obtained by subtracting a predetermined amount β from the set vehicle speed SPD* (S50).

[0030] If CPU32 determines that the value is less than the value obtained by subtracting a predetermined amount β (S50: NO), it determines whether the interval time is less than the threshold t4 (S52). Also, if CPU32 determines that the braking force is zero or less (S46: NO), it determines whether the vehicle speed SPD is greater than or equal to the value obtained by subtracting a predetermined amount β from the set vehicle speed SPD* (S54). If CPU32 determines that the value is less than the value obtained by subtracting a predetermined amount β (S54: NO), it determines whether the interval time is less than the threshold t3 (S56). Threshold t3 is greater than threshold t2 but less than threshold t4. If CPU32 determines that the value is less than threshold t3 (S56: YES), it proceeds to the process in S58 (labeled as acceleration determination process in the figure).

[0031] Figure 4 shows the details of the process in S58. In the series of processes shown in Figure 4, the CPU 32 first acquires position data Dgps (S70). Next, based on the position data Dgps, the CPU 32 extracts the gradient θ of the road surface on which the vehicle VC is currently traveling from the map data 80 (S72). The CPU 32 also extracts a variable value from the map data 80 indicating whether or not the vehicle VC is traveling inside a tunnel, based on the position data Dgps (S74). Then, based on the result of the process in S74, the CPU 32 determines whether or not the vehicle VC is currently traveling inside a one-way tunnel (S76). If the CPU 32 determines that the vehicle is traveling inside a one-way tunnel (S76: YES), it assigns the tunnel threshold θ1 to the threshold θth (S78). The threshold θth is the value that is compared with the gradient θ obtained in the process in S72. The threshold θth is set to the value at which the vehicle VC accelerates due to coasting. In this embodiment, the gradient θ is positive for uphill slopes and negative for downhill slopes.

[0032] On the other hand, if the CPU 32 determines that the vehicle is not traveling in a one-way tunnel (S76: NO), it substitutes the reference threshold θ2 for the threshold θth (S80). The reference threshold θ2 is smaller than the tunnel threshold θ1. In other words, both the reference threshold θ2 and the tunnel threshold θ1 are negative values, and the absolute value of the reference threshold θ2 is greater than the absolute value of the tunnel threshold θ1. If the CPU 32 completes the processing in S78 and S80, it determines whether the gradient θ is less than or equal to the threshold θth (S82). If the CPU 32 determines that the gradient θ is less than or equal to the threshold θth (S82: YES), it makes an acceleration determination, which is a determination that the vehicle VC will accelerate due to the coasting process (S84).

[0033] Furthermore, CPU32 completes the S58 process when it finishes processing S84, and when it makes a negative determination in processing S82. Returning to Figure 3, the CPU 32 determines whether or not acceleration was detected in the process of S58 (S60). If the CPU 32 determines affirmatively in the processes of S52, S54, and S60, it switches to coasting mode (S62). In other words, the CPU 32 switches to coasting mode in cruise mode if any of the following conditions are met.

[0034] Condition (H): This condition is true if the logical AND of the following is true: braking force is zero or less, vehicle speed SPD is less than the value obtained by subtracting a predetermined amount β from the set vehicle speed SPD*, the interval between vehicles is less than the threshold t3, and the gradient θ is less than or equal to the threshold θth. The threshold t3 is set to a value greater than threshold t2 and less than threshold t4.

[0035] Condition (I): The logical AND of the following conditions is true: the braking force is positive, the vehicle speed SPD is less than the value obtained by subtracting a predetermined amount β from the set vehicle speed SPD*, and the interval between vehicles is greater than or equal to threshold t2 and less than threshold t4.

[0036] Condition (J): This condition is true if the logical AND of the following two conditions is true: the braking force is zero or less, and the vehicle speed SPD is greater than or equal to the value obtained by subtracting a predetermined amount β from the set vehicle speed SPD*. When CPU32 completes processing S42 and S62, when it makes a negative determination in processing S30, S44, S48, S52, S56, and S60, and when it makes a positive determination in processing S38, it temporarily terminates the series of processes shown in Figure 3.

[0037] Now, the operation and effects of this embodiment will be described. When the CPU 32 is performing cruise control, if the above condition (H) is met, it switches to coasting mode. Here, if the vehicle VC is traveling in a one-way tunnel, the CPU 32 switches to coasting mode even if the downhill slope is gentler than in other cases.

[0038] Figure 5(a) shows the case where a vehicle VC travels outside a tunnel, while Figure 5(b) shows the case where a vehicle VC travels inside a one-way tunnel. In Figure 5, the vehicle VC is identified by the number in parentheses after "VC". Specifically, Figure 5 shows "Vehicle VC(1)" and "Preceding Vehicle VC(2)" relative to Vehicle VC(1).

[0039] Figure 5(a) shows a case where the cruising mode is maintained outside the tunnel because the gradient θ is greater than the reference threshold θ2. Figure 5(b) shows an example where the vehicle switches to coasting mode in a one-way tunnel because the gradient θ is less than the tunnel threshold θ1. Note that the gradient θ shown in Figure 5(a) and the gradient θ shown in Figure 5(b) are assumed to be the same magnitude.

[0040] In the one-way tunnel shown in Figure 5(b), an airflow is formed that moves in the direction of travel. This airflow is generated by vehicles traveling through the one-way tunnel. Some one-way tunnels are also equipped with ventilation fans. When ventilation fans are installed, they create airflow. This airflow acts as a tailwind for the vehicle VC. Therefore, even if the gradient θ is the same, the longitudinal acceleration of the vehicle VC due to coasting tends to be greater inside a one-way tunnel compared to outside the tunnel.

[0041] Figure 5 shows examples where vehicle VC(1) is preceded by vehicle VC(2). The CPU 32 controls the vehicle to prevent the time between it and vehicle VC(2) from becoming excessively large. Therefore, in situations where deceleration occurs due to coasting, the switch from cruise mode to coasting mode may not occur. This situation is shown in Figure 5(a). Even with a gradient θ of such magnitude, vehicle VC(1) is expected to accelerate inside a one-way tunnel. Therefore, the CPU 32 switches to coasting mode.

[0042] This allows for precise control of the following distance and vehicle speed SPD while reducing the energy consumption rate of the vehicle's VC. <Second Embodiment> The second embodiment will be described below, focusing on the differences from the first embodiment, with reference to the drawings.

[0043] In the first embodiment described above, the gradient θ of the road surface on which the vehicle VC is currently traveling was used as the input for determining whether to switch to coasting mode. In contrast, in this embodiment, the gradient θx of the road surface on which the vehicle VC is predicted to travel in the near future is used as the input.

[0044] Figure 6 shows the details of the process S58 according to this embodiment. Note that, for convenience, the same step numbers are assigned to the processes corresponding to those shown in Figure 4 in Figure 6, and their explanations are omitted.

[0045] In the series of processes shown in Figure 6, if the CPU 32 completes the process in S70, it extracts the gradient θx at the time X elapsed between vehicles (S72a). This process can be executed as follows: First, the CPU 32 identifies the position after the time X has elapsed based on the current value on the map identified from the position data Dgps and map data 80, and the time X elapsed between vehicles calculated using the vehicle speed SPD as input. Then, the CPU 32 extracts the gradient θx at that position by searching the map data 80 for data related to the identified position.

[0046] Next, the CPU 32 extracts tunnel information at the time X has elapsed between vehicles (S74a). Then, based on the processing in S74a, the CPU 32 determines whether or not vehicle VC is traveling inside a one-way tunnel at the time X has elapsed (S76a).

[0047] Next, if the CPU 32 determines that the result in S76a is positive, it proceeds to the process in S78; otherwise, it proceeds to the process in S80. When the CPU 32 completes the process in S78 or S80, it determines whether the gradient θx is less than or equal to the threshold θth (S82a). If the CPU 32 determines that it is less than or equal to the threshold θth (S82a: YES), it proceeds to the process in S84.

[0048] Furthermore, CPU32 completes the process in S58 when it completes the process in S84, or when it makes a negative determination in the process in S82a. Thus, in this embodiment, the gradient θx of a point where the vehicle VC will travel in the near future was used as input to determine whether or not to switch to coasting mode. This increases the opportunities to perform coasting when it is appropriate to do so.

[0049] <Third Embodiment> The third embodiment will be described below, focusing on the differences from the first embodiment, with reference to the drawings.

[0050] Figure 7 shows the details of the process S58 according to this embodiment. Note that, for convenience, the same step numbers are assigned to the processes corresponding to those shown in Figure 4 in Figure 7, and their explanations are omitted.

[0051] In the series of processes shown in Figure 7, if the CPU 32 completes the process in S72, it obtains the output signals Ssb(1) to Ssb(5) (S86). Then the CPU 32 proceeds to the process in S74. If the CPU 32 makes a positive determination in the process in S76, it proceeds to the process in S78a. In the process in S78a, the CPU 32 sets a threshold θth according to the number of occupants. Here, the CPU 32 calculates the number of occupants using the output signals Ssb(1) to Ssb(5) as input. The CPU 32 also calculates a larger threshold θth value, assuming that the total weight of the occupants is smaller the fewer occupants there are. This setting is based on the consideration that the smaller the total weight, the easier it is to accelerate even on a gentle slope.

[0052] On the other hand, if the CPU 32 determines that the process in S76 is positive, it proceeds to the process in S80a. In the process in S80a, the CPU 32 sets a threshold θth according to the number of occupants. The CPU 32 assumes that the total weight of the occupants is smaller when there are fewer occupants, and calculates a larger threshold θth. However, for the same number of occupants, the CPU 32 calculates a smaller threshold θth in the process in S80a compared to the process in S78a.

[0053] Furthermore, once CPU32 has completed processing S78a and S80a, it will proceed to processing S82. Thus, in this embodiment, even if the magnitude of the gradient θ is the same, the ease of acceleration of the vehicle VC can differ, and in addition to whether or not it is in a one-way tunnel, the number of occupants is also taken into consideration. This allows for a more appropriate switch to coasting mode. That is, for example, if the threshold θth, which is set independently of the number of occupants, is set to a value that ensures the vehicle VC accelerates reliably through coasting, it becomes necessary to set it to a value that accelerates even when the number of occupants is at its maximum. This can lead to a situation where, when the number of occupants is small, the vehicle VC actually accelerates through coasting, but the switch to coasting mode is not performed. In contrast, according to this embodiment, the frequency of execution of coasting can be increased as much as possible.

[0054] <Other Embodiments> Furthermore, this embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0055] "Regarding pre-fetching" In the process shown in Figure 6, the condition that the threshold θth is set to the tunnel threshold θ1 may be amended to include the condition that the vehicle is currently located inside a tunnel with one-way traffic, in addition to the condition that the vehicle is inside a tunnel with one-way traffic after a time interval of X has elapsed.

[0056] In the process shown in Figure 6, even if the gradient θx is less than or equal to the threshold θth, the vehicle may choose not to switch to coasting mode if the gradient θ of the road surface it is currently traveling on is excessively large. In the process shown in Figure 7, the comparison target with the threshold θth may be the gradient θx at the time X elapsed between vehicles.

[0057] "Regarding deviation variables" The variable indicating the weight of the vehicle VC's occupants is not limited to a variable indicating the number of occupants. For example, it could be the sum of the weights of the vehicle VC's occupants. This can be achieved, for example, by having the vehicle VC's user register their weight on their mobile device and then sending that weight information to ADASECU30 from the same mobile device. This process can be achieved by pre-installing dedicated application software on the mobile device. Alternatively, the interior image data output by the in-vehicle camera that captures images of the vehicle VC's interior can be analyzed to estimate that the taller the occupant, the heavier their weight. In that case, the value obtained by this estimation becomes the value of the variable indicating weight.

[0058] The variable indicating the weight of the vehicle VC is not limited to a variable that has a positive correlation with the number of occupants. For example, it could be a variable indicating the weight of objects in the cargo area. In that case, the value of this variable can be estimated using, for example, image data output by a camera that captures images of objects in the cargo area. That is, for example, the weight can be estimated to be a larger value in proportion to the size of the imaged object.

[0059] • Among the deviation variables, the variable indicating the driving environment of the vehicle VC is not limited to the variable indicating whether or not it is a one-way tunnel. For example, it could be a variable indicating whether or not the preceding vehicle traveling within a predetermined distance in front of the vehicle VC is a large vehicle such as a truck. In that case, if it is a large vehicle, the air resistance will be smaller, so it is sufficient to switch to coasting mode even on a gentler gradient.

[0060] "Regarding the switching process" Switching to coasting mode based on a comparison of the magnitudes of the gradient θ and the threshold θth is not limited to when the above condition (H) is met. For example, instead of setting the threshold θth according to the time between vehicles in addition to whether or not the vehicle is traveling through a one-way tunnel, the logic for switching to coasting mode when condition (H) is met may be removed. Here, it is desirable that the threshold θth be a negative value with a larger absolute value as the time between vehicles increases.

[0061] In the above embodiment, the vehicle switched to cruise mode when the S44 process was positive, but this is not limited to this. For example, if the gradient θ is negative and has a large absolute value, the vehicle may continue coasting, assuming that sufficient acceleration is possible.

[0062] The switching process is not limited to switching to coasting when it is predicted that the vehicle will accelerate as a result. For example, the vehicle may switch to coasting when it is predicted that the current vehicle speed will be maintained as a result. This switching process may be executed, for example, when the vehicle speed SPD is greater than or equal to "SPD*-β" and less than or equal to "SPD*+α".

[0063] The switching process is not limited to switching to coasting mode when the gradient θ,θx is less than or equal to a threshold θth. For example, the switching process may be performed according to the value of a dependent variable of a function that takes the gradient θx and the value of the deviation variable as input variables and outputs a variable value that selectively indicates either cruising mode or coasting mode. Note that this function is designed so that, for example, when the value of the deviation variable indicates that the vehicle is in a one-way tunnel, the value of the dependent variable will indicate coasting mode even if the gradient θx is greater than when it does not.

[0064] "Regarding the driving control system" In the above embodiment, the ADASECU30, as a driving control device, receives the object recognition results from the LIDARECU12, which have undergone clustering processing on the distance measurement point cloud data Drpc. However, the embodiment is not limited to this. For example, the ADASECU30 may perform the processing that the LIDARECU12 performed in the above embodiment.

[0065] In the above embodiment, the ADASECU30, as a driving control device, receives the recognition result of an object whose image data Dpo has been processed by the image ECU22, but it is not limited to this. For example, the ADASECU30 may perform the processing that the image ECU22 performed in the above embodiment.

[0066] The driving control device is not limited to one that includes a CPU 32 and a storage device 34 to perform software processing. For example, it may include a dedicated hardware circuit, such as an ASIC, that performs hardware processing for at least a portion of what is processed by software in the above embodiment. That is, the execution device may have any of the following configurations (a) to (c): (a) It includes a processing unit that performs all of the above processing according to a program and a program storage unit that stores the program. (b) It includes a processing unit and a program storage unit that perform a portion of the above processing according to a program and a dedicated hardware circuit that performs the remaining processing. (c) It includes a dedicated hardware circuit that performs all of the above processing. Here, there may be multiple software execution devices equipped with a processing unit and a program storage unit, or multiple dedicated hardware circuits.

[0067] "About computers" The computer is not limited to a single CPU 32, as illustrated in Figure 1. Furthermore, it is not limited to a computer installed in the vehicle, as illustrated in Figure 1. For example, the processing shown in Figure 4 may be executed by a CPU installed in the driver's mobile device. In that case, the computer installed in the vehicle and the computer not installed in the vehicle will communicate and cooperate to execute the driving control program 34a.

[0068] "Other" • In the above embodiment, an example of object recognition based on distance measurement point cloud data Drpc output by the optical sensor 10 and image data Dpo output by the camera 20 was shown, but the method is not limited to this. For example, distance measurement data output by a radar device such as a millimeter-wave radar may also be taken into consideration. However, it is not essential to use so-called sensor fusion, which performs object recognition based on the detection values ​​of multiple sensors. [Explanation of Symbols]

[0069] 30…ADASECU 40…Local network

Claims

1. The following processes are executed: coasting, cruising, gradient information acquisition (S72, S72a), deviation variable acquisition (S74, S74a, S86), and switching (S62). The aforementioned coasting process is a process of causing the vehicle to coast, The aforementioned cruise control process is a process that controls the vehicle's speed to a set speed while prioritizing the fulfillment of predetermined conditions. The aforementioned predetermined condition is the condition that when a preceding vehicle is present within a predetermined range in front of the vehicle, the distance to the preceding vehicle is maintained within a predetermined range. The aforementioned gradient information acquisition process is a process for acquiring gradient information of the road surface on which the vehicle is traveling. The aforementioned deviation variable acquisition process is a process that acquires a deviation variable, which is a variable that determines the acceleration generated in the vehicle when the vehicle travels down a slope with a predetermined gradient using the coasting process, separately from the gradient information. The switching process takes the gradient information and the deviation variable as input and switches to the coasting process when the vehicle is traveling downhill while the cruising process is being executed, and includes a process in which, if the value of the deviation variable is a first value, the process switches to the coasting process if the absolute value of the gradient of the downhill slope is less than or equal to a first threshold, while if the value of the deviation variable is a second value, the process switches to the coasting process if the absolute value of the gradient of the downhill slope is less than or equal to a second threshold. The second value is a value that produces a greater acceleration than the first value when traveling downhill by coasting, The process includes a value such that the second threshold is smaller than the first threshold, The aforementioned gradient is negative when it is a downhill slope.

2. The driving control device according to claim 1, wherein the vehicle is accelerated by executing the coasting process through the switching process.

3. The aforementioned deviation variable includes a variable indicating whether or not the vehicle is traveling through a tunnel with one-way traffic. The driving control device according to claim 1 or 2, wherein the switching process includes a process to switch to the coasting process when the vehicle is traveling through a tunnel with one-way traffic, even though the magnitude of the gradient is smaller than when the vehicle is not traveling.

4. The driving control device according to any one of claims 1 to 3, wherein the switching process is a process of switching to the coasting process when the vehicle is traveling downhill, based on input of the gradient information of the road surface on which the vehicle is expected to travel when the vehicle has moved forward a predetermined distance.

5. The aforementioned deviation variable includes a variable indicating the weight of the vehicle's occupants, The driving control device according to any one of claims 1 to 4, wherein the switching process includes a process to switch to the coasting process when the number of occupants is small, even though the magnitude of the gradient is smaller compared to when there are many occupants.

6. A driving control method comprising the step of performing each of the processes described in any one of claims 1 to 5.

7. A driving control program that causes a computer to perform each of the processes described in any one of claims 1 to 5.

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