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

Abstract

A vehicle control device comprising: a target torque calculation unit that calculates a first target torque for changing the inter-vehicle distance between a preceding vehicle and a following vehicle following the preceding vehicle; a torque recording unit that records an actual torque generated on the basis of the first target torque, until the inter-vehicle distance reaches a specific inter-vehicle distance between the following vehicle and the preceding vehicle; and a distance setting unit that sets, for the inter-vehicle distance, a corresponding inter-vehicle distance corresponding to a value within a specific range including a minimum value among the recorded actual torques.

Description

Vehicle control device, vehicle control program, and vehicle control method CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims the benefit of priority from Patent Application No. 2023-203182, filed November 30, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a vehicle control device, a vehicle control program, and a vehicle control method.

[0003] The conventional technology disclosed in Patent Document 1 calculates the rate of change in air resistance based on a reference torque and an actual torque, and causes vehicles to travel in a convoy at a distance that satisfies a target rate of change in air resistance.

[0004] Japanese Patent Application Laid-Open No. 2021-059131

[0005] As a result of detailed investigation by the inventors, it was found that, with the conventional technology, even if the rate of increase or decrease in air resistance satisfies the target value, the following vehicle is not necessarily traveling at an inter-vehicle distance at which the gain can be maximized or close to the maximum, i.e., at an inter-vehicle distance at which the running resistance can be minimized or close to the minimum. As such, the conventional technology has room for improvement in terms of suppressing the consumption of running energy by the following vehicle following the leading vehicle.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a vehicle control device, a vehicle control program, and a vehicle control method that suppress the consumption of traveling energy by a following vehicle.

[0007] In order to achieve the above-mentioned object, the vehicle control device of the present disclosure includes a target torque calculation unit that calculates a first target torque that changes the inter-vehicle distance from a leading vehicle to a following vehicle following the leading vehicle, a torque recording unit that records the actual torque generated based on the first target torque until the inter-vehicle distance reaches a specific inter-vehicle distance to be maintained between the following vehicle and the leading vehicle, and a distance setting unit that sets a corresponding inter-vehicle distance to a value within a specific range including the minimum value of the recorded actual torque.

[0008] The vehicle control program of the present disclosure causes at least one processor to execute processing including calculating a first target torque that changes the inter-vehicle distance from a leading vehicle to a following vehicle following the leading vehicle, recording the actual torque generated based on the first target torque until the inter-vehicle distance reaches a specific inter-vehicle distance to be maintained between the following vehicle and the leading vehicle, and setting the inter-vehicle distance to a corresponding inter-vehicle distance that corresponds to a value within a specific range including the minimum value of the recorded actual torque.

[0009] The vehicle control method disclosed herein executes processing in which at least one processor calculates a first target torque that changes the inter-vehicle distance from a leading vehicle to a following vehicle following the leading vehicle, records the actual torque generated based on the first target torque until the inter-vehicle distance reaches a specific inter-vehicle distance to be maintained between the following vehicle and the leading vehicle, and sets the inter-vehicle distance to a corresponding inter-vehicle distance that corresponds to a value within a specific range including the minimum value of the recorded actual torque.

[0010] According to the present disclosure, it is possible to reduce the consumption of energy required for driving by a following vehicle.

[0011] FIG. 1 is a diagram illustrating a vehicle equipped with a vehicle control device according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating a hardware configuration of the vehicle control device according to an embodiment of the present disclosure. FIG. 3 is a diagram illustrating functional blocks of the vehicle control device according to an embodiment of the present disclosure. FIG. 4 is a flowchart illustrating the operation of the vehicle control device according to an embodiment of the present disclosure. FIG. 5 is a diagram illustrating the operation of the vehicle control device according to an embodiment of the present disclosure. FIG. 6 is a diagram illustrating the operation of the vehicle control device according to an embodiment of the present disclosure. FIG. 7 is a diagram illustrating the operation of the vehicle control device according to an embodiment of the present disclosure. FIG. 8 is a diagram illustrating the operation of the vehicle control device according to an embodiment of the present disclosure. FIG. 9 is a diagram illustrating the operation of the vehicle control device according to an embodiment of the present disclosure. FIG. 10 is a diagram illustrating the operation of the vehicle control device according to an embodiment of the present disclosure. FIG. 11A is a diagram illustrating a method of correcting actual torque. FIG. 11B is a diagram illustrating a method of correcting actual torque. FIG. 11C is a diagram illustrating a method of correcting actual torque. FIG. 12 is a flowchart illustrating the operation of the vehicle control device when correcting the amount of lateral deviation. FIG. 13 is a diagram illustrating a following vehicle before and after the amount of lateral deviation is corrected. FIG. 14 is a flowchart illustrating a method of estimating vehicle weight. Fig. 15 is a flow chart for explaining the operation of the vehicle control device when a cutting-in vehicle is detected, and Fig. 16 is a diagram showing the following vehicles before and after the cutting-in vehicle is detected.

[0012] Hereinafter, one embodiment of the present disclosure will be described.

[0013] 1 is a diagram illustrating a vehicle 100 equipped with a vehicle control device according to an embodiment of the present disclosure. The vehicle 100 may include a battery 101, an inverter 102, a motor 103, an EPS (Electric Power Steering) 104, a brake ECU (Electronic Control Unit) 105, a vehicle distance calculation unit 106, a sensor group 200, and a vehicle control device 300.

[0014] The battery 101 may be interpreted as a power storage device including a plurality of cells. The battery 101 may store power to drive the motor 103 and may also store power regenerated from the motor 103. Each of the plurality of cells may be interpreted as a secondary battery such as a lithium ion battery, a nickel-metal hydride battery, or a lithium iron phosphate battery.

[0015] The inverter 102 may be interpreted as a device that controls the rotation of the motor 103. The inverter 102 may convert DC power supplied from the battery 101 into AC power in accordance with the torque from the vehicle control device 300, and supply the AC power to the motor 103, thereby controlling the rotation of the motor 103. One or more inverters 102 may be provided in the vehicle 100.

[0016] The motor 103 may be interpreted as a traction motor that generates driving force to run the vehicle 100. The motor 103 may generate rotational torque to run the vehicle 100 using AC power supplied from the inverter 102. One or more motors 103 may be provided in the vehicle 100. The rotational torque of the motor 103 is transmitted to a drive train 107. The drive train 107 may include a driving force transmission system for the front wheels, tires for the front wheels, a driving force transmission system for the rear wheels, tires for the rear wheels, etc.

[0017] The EPS 104 may be considered as a system that assists steering of the steering wheel using an electric motor. The brake ECU 105 may brake each wheel of the vehicle 100 by driving an actuator (not shown) according to the braking amount.

[0018] The sensor group 200 may include a brake oil pressure sensor 201 , a wheel speed sensor 202 , a resolver 203 , an acceleration sensor 204 , a motor output current sensor 206 , and an external sensor 207 .

[0019] The brake oil pressure sensor 201 may be interpreted as a sensor that detects brake oil pressure. The wheel speed sensor 202 may be interpreted as a sensor that detects the wheel speed (vehicle speed) of the vehicle 100. The resolver 203 may be interpreted as a sensor that detects the rotation angle of the rotor provided in the motor 103. The acceleration sensor 204 may be interpreted as a sensor that detects the acceleration of the vehicle 100. The motor output current sensor 206 may be interpreted as a sensor that detects the output current supplied to the motor 103.

[0020] The external sensor 207 may be interpreted as a sensor that detects the surrounding conditions of the vehicle 100. The external sensor 207 may include a sensor (such as an on-board millimeter-wave radar, a camera, an on-board sonar sensor, or a LiDAR (Light Detection and Ranging)) that detects the inter-vehicle distance from the following vehicle to the leading vehicle and outputs the detected inter-vehicle distance as inter-vehicle distance information. The inter-vehicle distance calculation unit 106 may calculate the inter-vehicle distance between the leading vehicle and the following vehicle based on the inter-vehicle distance information from the external sensor 207. The following vehicle may be interpreted as the vehicle 100 of the present disclosure.

[0021] The vehicle control device 300 may be interpreted as a device that controls the inverter 102. The vehicle control device 300 may control the rotation speed, rotation direction, torque, etc. of the motor 103 by controlling the inverter 102. The configuration of the vehicle control device 300 will be described in detail later.

[0022] Next, the hardware configuration of the vehicle control device 300 will be described with reference to Fig. 2. Fig. 2 is a diagram showing the hardware configuration of the vehicle control device 300 according to an embodiment of the present disclosure.

[0023] The vehicle control device 300 may include an input / output interface (I / F) 1, a memory 2, and a processor 3. These may be communicably connected via a bus 4.

[0024] The input / output I / F 1 may be interpreted as an interface for communicating with the on-board device shown in Fig. 1. The on-board device may include the sensor group 200, the inverter 102, the EPS 104, the brake ECU 105, the inter-vehicle distance calculation unit 106, and the like shown in Fig. 1.

[0025] The memory 2 may store a vehicle control program 2a for controlling the motor 103 and the like shown in Fig. 1. The processor 3 may execute specific processing by deploying the vehicle control program 2a. Functions realized by the vehicle control program 2a will be described with reference to Fig. 3.

[0026] Next, the functional configuration of the vehicle control device will be described with reference to Fig. 3. Fig. 3 is a diagram showing functional blocks of a vehicle control device 300 according to an embodiment of the present disclosure.

[0027] The vehicle control device 300 may include an inter-vehicle distance output unit 301, a friction coefficient estimation unit 302, and a torque output unit 303. The inter-vehicle distance output unit 301, the friction coefficient estimation unit 302, and the torque output unit 303 may be realized by the processor 3 shown in FIG. 2 executing a vehicle control program 2 a.

[0028] (Inter-vehicle distance output unit 301) The inter-vehicle distance output unit 301 may estimate the inter-vehicle distance at which the actual torque (running resistance) of the following vehicle following the preceding vehicle when traveling is minimum or close to minimum, based on vehicle information, and output information indicating the inter-vehicle distance.

[0029] The vehicle information may include a follow-up travel permission signal, a vehicle-to-vehicle distance, a lateral deviation amount, a steering angle, a vehicle speed, a gradient, an actual torque, a rotation speed of the motor 103, a brake torque, etc. The vehicle control device 300 may calculate the gradient based on a value detected by a longitudinal acceleration sensor, an acceleration calculated from the wheel speed, etc.

[0030] The follow-up travel permission signal may be interpreted as a signal indicating that the following vehicle is permitted to travel following the leading vehicle. For example, the follow-up travel permission signal may be output when the driver arbitrarily sets a distance to maintain a certain distance between the leading vehicle and the following vehicle. The lateral deviation amount may be interpreted as the relative deviation amount of the following vehicle in the lateral width direction with respect to the leading vehicle. The lateral deviation amount may be interpreted as the deviation amount of the following vehicle in the lateral width direction from the center of the leading vehicle in the lateral width direction (vehicle width direction).

[0031] The actual torque may be interpreted as the torque generated by the motor 103. Because there is a certain correlation between the current flowing through the motor 103 and the torque generated by the motor 103, the actual torque may be calculated based on the current, the angular velocity of the motor 103, etc. The current may be large when the running resistance is large, and may be small when the running resistance is small.

[0032] The inter-vehicle distance output unit 301 may include a torque recording unit 10, a distance setting unit 11, a lateral deviation amount correction unit 12, a vehicle weight estimation unit 13, a safe inter-vehicle distance calculation unit 14, and the like.

[0033] (Torque Recording Unit 10) The torque recording unit 10 may record the actual torque generated based on the first target torque until the inter-vehicle distance reaches (is equal to) a specific inter-vehicle distance, for example.

[0034] The first target torque may be interpreted as a target torque calculated by the target torque calculation unit 16. The first target torque may also be interpreted as a target torque that changes the inter-vehicle distance, a target motor torque, or the like.

[0035] The specific following distance may be interpreted as a distance arbitrarily set by a driver to maintain a certain distance between a leading vehicle and a following vehicle when cruise control (CC) is set, for example. The specific following distance may be interpreted as a safe following distance to be maintained between a following vehicle and the leading vehicle. The safe following distance may be interpreted as a distance that increases the possibility of avoiding a collision of the following vehicle with the leading vehicle. Specifically, the safe following distance may be interpreted as a braking distance that can avoid a collision of the following vehicle with the leading vehicle, a cutting-in vehicle, etc., or a distance obtained by adding a free-running distance to the braking distance. The free-running distance may be interpreted as the distance traveled from the time the driver senses danger and applies the brakes until the brakes actually start to operate. The braking distance may be interpreted as the distance traveled from the time the brakes are applied until the following vehicle stops.

[0036] Examples of actual torque recorded by the torque recording unit 10 will be described with reference to Figures 6 to 10. These figures show actual torque that changes depending on the inter-vehicle distance, etc. The vertical axis represents actual torque, and the horizontal axis represents inter-vehicle distance. These figures also show the minimum value of actual torque, actual torque within a specific range including the minimum value, etc.

[0037] The specific range may be interpreted as a certain range from the inter-vehicle distance corresponding to the minimum value of the actual torque. For example, if the inter-vehicle distance is 30 m, the certain range may be interpreted as a distance equivalent to X% of 30 m (e.g., ±3 m). X% may include any value from several percent to several tens of percent, taking into account errors in the detection accuracy of the external sensor 207, the detection accuracy of the actual torque, and the like.

[0038] The actual torque within the specific range may include the minimum value of the actual torque, an actual torque that can be considered equivalent to this minimum value, etc. Specifically, the actual torque within the specific range may include the minimum actual torque, the actual torque that is next smallest after the minimum actual torque, etc.

[0039] In this way, the torque recording unit 10 may chronologically record the actual torque generated based on the first target torque calculated so that the following vehicle approaches the leading vehicle until the inter-vehicle distance reaches, for example, a safe inter-vehicle distance (specific inter-vehicle distance). This makes it possible to search for an inter-vehicle distance at which the air resistance, i.e., running resistance, of the following vehicle traveling following the leading vehicle is at or near the minimum. In other words, it is possible to search for an inter-vehicle distance at which the following vehicle consumes less energy to run.

[0040] (Another configuration example 1 of the torque recording unit 10) The torque recording unit 10 may record the actual torque after correcting the actual torque based on at least one of the vehicle speed of the following vehicle, the gradient of the following vehicle, and the steering angle of the following vehicle.

[0041] In this way, by correcting the actual torque based on the gradient, steering angle, etc., it is possible to record the actual torque according to the driving conditions of the following vehicle, thereby improving the accuracy of the inter-vehicle distance that reduces the driving energy consumption of the following vehicle. The method of correcting the actual torque will be described in detail later.

[0042] (Another Configuration Example 2 of the Torque Recording Unit 10) The torque recording unit 10 may record the actual torque when the lateral deviation amount of the following vehicle is within a specific range. Specifically, the torque recording unit 10 may record the actual torque when it receives information indicating that the lateral deviation amount is within the specific range. The torque recording unit 10 may stop recording the actual torque when it does not receive the information.

[0043] This allows the actual torque to be recorded with most of the body of the following vehicle positioned within the projected area (projected region) of the leading vehicle, so that a smaller actual torque can be recorded. Details of the lateral deviation correction operation for keeping the lateral deviation amount within a specific range will be described later.

[0044] (Another Example Configuration 3 of the Torque Recording Unit 10) The torque recording unit 10 may further record the actual torque generated based on the first target torque when the following vehicle approaches the leading vehicle up to a specific distance where the inter-vehicle distance becomes shorter than the safe inter-vehicle distance (specific inter-vehicle distance). For example, if the safe inter-vehicle distance is 20 m, the specific distance may be interpreted as the inter-vehicle distance (e.g., 15 m) obtained by subtracting a distance equivalent to N% of 20 m (e.g., 5 m) from 20 m. N% may include any value ranging from several percent to several tens of percent, taking into account errors in the detection accuracy of the external sensor 207, the detection accuracy of the actual torque, and the like.

[0045] By recording the actual torque up to a specific distance, it is possible to search for an inter-vehicle distance at which the following vehicle will consume less energy to run.

[0046] (Distance setting unit 11) The distance setting unit 11 may set an appropriate inter-vehicle distance corresponding to a value (minimum value, etc.) within a specific range of the actual torque recorded as shown in, for example, Figures 6 to 9, as the inter-vehicle distance between the leading vehicle and the following vehicle. The distance setting unit 11 may output information about the set appropriate inter-vehicle distance to the target torque calculation unit 16.

[0047] The corresponding inter-vehicle distance may be interpreted as the inter-vehicle distance corresponding to the minimum actual torque, or as the inter-vehicle distance corresponding to the actual torque next to the minimum actual torque. When there are multiple minimum actual torques with the same value, the corresponding inter-vehicle distance may be interpreted as the inter-vehicle distance corresponding to any one of these actual torques. When there are multiple minimum actual torques with the same value, the corresponding inter-vehicle distance may be interpreted as the inter-vehicle distance corresponding to the value of these actual torques that corresponds to the position where the following vehicle is farthest from the leading vehicle.

[0048] By setting the corresponding inter-vehicle distance as the inter-vehicle distance in this manner, the target torque calculation unit 16 can calculate the second target torque based on the corresponding inter-vehicle distance. The second target torque may be interpreted as a target torque for maintaining the corresponding inter-vehicle distance, i.e., a distance that reduces the driving energy consumption of the following vehicle. The configuration of the target torque calculation unit 16 will be described in detail later.

[0049] (Another Example Configuration 1 of Distance Setting Unit 11) When there is one value when the actual torque changes from decreasing to increasing (for example, the actual torque indicated by the dashed line in FIG. 8 ), the distance setting unit 11 may set the corresponding inter-vehicle distance as a value within a specific range. This makes it possible to set an inter-vehicle distance that minimizes the consumption of driving energy by the following vehicle.

[0050] (Another Example Configuration 2 of Distance Setting Unit 11) When there are multiple values ​​when the actual torque changes from decreasing to increasing (for example, the two actual torques indicated by dashed lines in FIGS. 9 and 10 ), the distance setting unit 11 may set the corresponding inter-vehicle distance as a value within a specific range among the multiple values. This reduces the processing time required to identify the minimum value by sequentially comparing the magnitudes of the actual torque in chronological order, and enables the setting of an inter-vehicle distance that can minimize the consumption of driving energy by the following vehicle.

[0051] (Another Example Configuration 3 of Distance Setting Unit 11) When there are multiple values ​​at which the actual torque changes from decreasing to increasing, the distance setting unit 11 may set the corresponding inter-vehicle distance to the lowest value (see FIG. 9 ) among the multiple values ​​within a specific range. This makes it possible to set an inter-vehicle distance that minimizes the consumption of driving energy by the following vehicle.

[0052] (Another Example Configuration 4 of Distance Setting Unit 11) When there are multiple values ​​when the actual torque changes from decreasing to increasing, and when the multiple values ​​are equal (see FIG. 10 ), the distance setting unit 11 may set the corresponding inter-vehicle distance as a value within a specific range, which is the value that corresponds to the position where the following vehicle is farthest from the leading vehicle. This makes it possible to set an inter-vehicle distance that minimizes the consumption of driving energy by the following vehicle while maintaining a safe inter-vehicle distance.

[0053] (Another example configuration 5 of distance setting unit 11) The distance setting unit 11 may compare the actual torque at a first point in time with the actual torque at a second point in time prior to the first point in time, and may set the corresponding inter-vehicle distance as the inter-vehicle distance by setting the actual torque whose value is smaller as a value within a specific range as the inter-vehicle distance.

[0054] Specifically, the distance setting unit 11 may compare the latest actual torque detected in chronological order with the minimum value of the actual torque detected up to the last time. The comparison may be continued until the following vehicle reaches a safe inter-vehicle distance (specific inter-vehicle distance), or until the following vehicle reaches (or becomes equal to) the specific distance described above.

[0055] If the comparison shows that the currently detected actual torque is smaller than the minimum value among the actual torques detected up to the last time, the distance setting unit 11 may set the corresponding inter-vehicle distance corresponding to the currently detected actual torque as the inter-vehicle distance. In other words, the inter-vehicle distance may be updated. On the other hand, if the currently detected actual torque is larger than the minimum value among the previously detected actual torques, the setting of the corresponding inter-vehicle distance corresponding to the minimum value among the previously detected actual torques may be maintained.

[0056] By comparing the magnitude of the actual torque in chronological order in this way, it is possible to easily set an inter-vehicle distance that will result in a value close to the minimum for the running energy consumption of the following vehicle.

[0057] (Another Example Configuration 6 of Distance Setting Unit 11) The distance setting unit 11 may set the corresponding inter-vehicle distance to the smallest value (minimum value) of the actual torque within a specific range, thereby making it possible to maintain an inter-vehicle distance that minimizes the consumption of the driving energy of the following vehicle.

[0058] (Another Example Configuration 7 of Distance Setting Unit 11) When the specific inter-vehicle distance is a safe inter-vehicle distance and the corresponding inter-vehicle distance is shorter than the safe inter-vehicle distance, the distance setting unit 11 may set the safe inter-vehicle distance instead of the corresponding inter-vehicle distance as the inter-vehicle distance. On the other hand, when the corresponding inter-vehicle distance is longer than the safe inter-vehicle distance, the distance setting unit 11 may set the corresponding inter-vehicle distance instead of the safe inter-vehicle distance as the inter-vehicle distance.

[0059] This makes it possible to reduce the running energy consumption of the following vehicle while maintaining a safe distance when the following distance is shorter than the safe following distance, and also makes it possible to reduce the running energy consumption of the following vehicle while maintaining a safer distance when the following distance is longer than the safe following distance.

[0060] (Another Example Configuration 8 of Distance Setting Unit 11) The distance setting unit 11 may set the corresponding inter-vehicle distance to the inter-vehicle distance during a period when a specific function is being executed. The specific function may include CC (cruise control), a platooning mode, an autonomous driving mode, an autonomous lane keeping mode, etc. For example, when a specific function is not being executed in the following vehicle, the distance setting unit 11 may not set the corresponding inter-vehicle distance to the inter-vehicle distance. When a specific function is being executed in the following vehicle, the distance setting unit 11 may set the corresponding inter-vehicle distance to the inter-vehicle distance.

[0061] In this way, by setting the corresponding inter-vehicle distance only while a specific function is being executed, it is possible to prevent the driver from feeling uncomfortable with accelerator operation when the specific function is not being executed, for example, because the vehicle is being driven manually. Also, at the driver's discretion, the vehicle can be shifted to a driving mode that reduces the driving energy consumption of the following vehicle.

[0062] (Lateral deviation amount correction unit 12) The lateral deviation amount correction unit 12 may correct the relative deviation amount (lateral deviation amount) of the following vehicle with respect to the preceding vehicle in the lateral width direction. Specifically, the lateral deviation amount may be kept within a specific range by adjusting the steering amount of the following vehicle based on image information including the image of the preceding vehicle captured by the imaging means.

[0063] If the calculated lateral deviation amount exceeds a specific range (specific amount), the lateral deviation amount correction unit 12 may adjust the steering amount of the following vehicle until the lateral deviation amount becomes less than the specific amount. If the lateral deviation amount is less than the specific amount, the lateral deviation amount correction unit 12 may output information indicating that the lateral deviation amount is within the specific range.

[0064] The specific range may be interpreted as a certain range from a position near the center in the width direction (vehicle width direction) of the preceding vehicle. The certain range may include any value, for example, from several percent to several tens of percent of the width of the preceding vehicle, taking into account errors such as the detection accuracy of the imaging means.

[0065] (Vehicle Weight Estimation Unit 13) The vehicle weight estimation unit 13 may estimate the weight (vehicle weight) of the vehicle 100. A vehicle weight estimation method will be specifically described with reference to Fig. 14 .

[0066] 14 is a flowchart illustrating a vehicle weight estimation method. In step S30, the vehicle weight estimation unit 13 may determine whether a start switch (e.g., an ignition switch) is turned on. If the start switch is turned on (step S30: YES), the vehicle weight estimation unit 13 may determine in step S31 whether the vehicle speed is less than 1 km / h.

[0067] If the vehicle speed is less than 1 km / h (step S31: YES), in step S32, the vehicle weight estimation unit 13 may output an instruction to output creep torque. When the torque output unit 303 outputs creep torque, in step S33, the vehicle weight estimation unit 13 may determine whether the vehicle speed is less than 6 km / h.

[0068] If the vehicle speed is less than 6 km / h (step S33: YES), in step S34, the vehicle weight estimation unit 13 may estimate the vehicle weight based on the actual torque generated at low speeds, the wheel speed change (ΔVwheel), the reference acceleration at the reference weight, etc.

[0069] (Friction Coefficient Estimation Unit 302) Returning to Fig. 3, the friction coefficient estimation unit 302 may estimate the friction coefficient of the road surface on which the vehicle 100 travels and output information indicating the estimated friction coefficient. Specifically, the friction coefficient estimation unit 302 may calculate the friction coefficient μ based on the actual torque (actual motor torque) and the brake torque. The friction coefficient estimation unit 302 may estimate the maximum μ value of the road surface by predicting the position of the peak of the friction coefficient (μ peak) using a cubic function approximation based on the calculated friction coefficient μ and slip ratio.

[0070] (Safe inter-vehicle distance calculation unit 14) The safe inter-vehicle distance calculation unit 14 may calculate the safe inter-vehicle distance based on at least one of the vehicle speed, the vehicle weight, and the friction coefficient of the road surface on which the following vehicle is traveling. The vehicle weight may be interpreted as the vehicle weight estimated by the vehicle weight estimation unit 13. The friction coefficient may be interpreted as the maximum μ value estimated by the friction coefficient estimation unit 302.

[0071] (Torque Output Unit 303) The torque output unit 303 may include a required torque calculation unit 15 and a target torque calculation unit 16.

[0072] (Required Torque Calculation Unit 15) The required torque calculation unit 15 may calculate a required torque according to the accelerator operation by the driver and output the calculated torque to the switching unit SW.

[0073] (Target Torque Calculation Unit 16) The target torque calculation unit 16 may calculate a first target torque that changes the inter-vehicle distance. The target torque calculation unit 16 may also calculate a second target torque for maintaining the corresponding inter-vehicle distance and output the second target torque to the switching unit SW instead of the first target torque. The switching unit SW may output either the torque output from the required torque calculation unit 15 or the torque output from the target torque calculation unit 16 to the inverter 102 (see FIG. 1).

[0074] (Another example of the configuration of the target torque calculation unit 16) The target torque calculation unit 16 may detect that a specific vehicle (cutting in vehicle) has cut in between the leading vehicle and the following vehicle during a period in which the following vehicle is performing driving control to follow the leading vehicle while maintaining the corresponding inter-vehicle distance described above.

[0075] In this case, the applicable inter-vehicle distance may become shorter than the specific inter-vehicle distance. When the applicable inter-vehicle distance becomes shorter than the specific inter-vehicle distance in this manner, the target torque calculation unit 16 may calculate a first target torque to make the applicable inter-vehicle distance longer than the specific inter-vehicle distance. Specifically, instead of the second target torque for maintaining the applicable inter-vehicle distance, the target torque calculation unit 16 may calculate a first target torque for increasing the inter-vehicle distance to a distance equivalent to twice the safe inter-vehicle distance (applicable inter-vehicle distance) before the cutting-in vehicle cuts in, and output the first target torque to the switching unit SW.

[0076] Furthermore, when the inter-vehicle distance exceeds a distance equivalent to twice the safe inter-vehicle distance (compatible inter-vehicle distance), the target torque calculation unit 16 may calculate a first target torque that changes the inter-vehicle distance so that the following vehicle approaches the leading vehicle, i.e., a first target torque that closes the inter-vehicle distance. At this time, the torque recording unit 10 may record the actual torque generated based on the first target torque until the inter-vehicle distance reaches a specific inter-vehicle distance. Then, the distance setting unit 11 may set the inter-vehicle distance to a compatible inter-vehicle distance that corresponds to a value within a specific range including the minimum value of the recorded actual torque.

[0077] This configuration makes it possible to minimize the driving energy consumption of the following vehicle following the cutting-in vehicle.

[0078] Next, the operation of the vehicle control device 300 will be described with reference to Figures 4 to 16. Figure 4 is a flowchart for explaining the operation of the vehicle control device according to the embodiment of the present disclosure.

[0079] When CC is set (ON) in step S1, the vehicle control device 300 determines in step S2 whether the set vehicle speed exceeds a specific vehicle speed (for example, 60 km / h).

[0080] If the vehicle speed is less than a specific vehicle speed (e.g., 60 km / h) (step S2: NO), the process of step S2 is repeatedly executed. If the vehicle speed exceeds the specific vehicle speed (step S2: YES), the process from step S3 onward is executed.

[0081] When low-torque search driving is permitted in step S3, the vehicle control device 300 may set a target speed for performing low-torque search driving in step S4. Low-torque search driving may be interpreted as a driving mode that searches for an inter-vehicle distance at which the actual torque is at or near its minimum value. Low-torque search driving may be activated, for example, in conjunction with CC or the like, or may be set (activated) manually by the driver.

[0082] The process of step S4 will be described in detail with reference to Fig. 5. The left side of Fig. 5 shows the following vehicle when starting low-torque exploratory driving. The following vehicle is traveling at a target speed V (= 70 km / h), for example, following the leading vehicle.

[0083] When low torque search driving is permitted, as shown in the center diagram of FIG. 5, the target speed V (=70 km / h) of the following vehicle is updated to, for example, target speed V+α (α=1 km / h).

[0084] Then, in step S5, the vehicle control device 300 may calculate a first target torque corresponding to the target speed of V+α. As a result, the following vehicle travels so as to close the gap with the leading vehicle, and the inter-vehicle distance from the following vehicle to the leading vehicle changes.

[0085] In step S6, the vehicle control device 300 compares the inter-vehicle distance with the safe inter-vehicle distance, and if the inter-vehicle distance is equal to or greater than the safe inter-vehicle distance (step S6: YES), in step S7, the vehicle control device 300 may record the actual torque corresponding to the inter-vehicle distance in chronological order. The processes of steps S6 and S7 may be repeatedly executed until the inter-vehicle distance becomes less than the safe inter-vehicle distance. In this way, the actual torque corresponding to the inter-vehicle distance can be recorded until the inter-vehicle distance becomes less than the safe inter-vehicle distance.

[0086] If the inter-vehicle distance is less than the safe inter-vehicle distance (step S6: NO), the vehicle control device 300 executes the process of step S8. In step S8, the vehicle control device 300 determines whether there are multiple values ​​when the recorded actual torque changes from decreasing to increasing.

[0087] For example, as shown in Figure 8, if there is one value at which the actual torque has changed from decreasing to increasing (step S8: NO), in step S9, the vehicle control device 300 may set the corresponding inter-vehicle distance as a value within a specific range.

[0088] For example, as shown in Figures 9 and 10, if there are multiple values ​​at which the actual torque changes from decreasing to increasing (step S8: YES), in step S10, the vehicle control device 300 may set one of these values ​​as a value within a specific range and set the corresponding inter-vehicle distance as the inter-vehicle distance.

[0089] Specifically, the vehicle control device 300 may set the corresponding inter-vehicle distance as the inter-vehicle distance by setting the lowest value of the multiple actual torques as a value within a specific range, as shown in Fig. 9. As shown in Fig. 10, when there are multiple values ​​at which the actual torque changes from decreasing to increasing and these values ​​are equal, the vehicle control device 300 may set the corresponding inter-vehicle distance as the value of the multiple values ​​that corresponds to the position where the following vehicle is farthest from the leading vehicle as a value within the specific range.

[0090] In step S11, the vehicle control device 300 may calculate a second target torque for maintaining the set corresponding inter-vehicle distance, and in step S12, output the second target torque instead of the first target torque. This makes it possible to maintain a specific inter-vehicle distance (optimal inter-vehicle distance) at which the torque of the following vehicle is small (low torque) while traveling, as shown in the diagram on the right side of Fig. 5. In other words, it is possible to maintain an inter-vehicle distance at which the traveling energy consumption of the following vehicle is minimum or close to minimum.

[0091] (Method of Correcting Actual Torque) The above-mentioned method of correcting the actual torque will be specifically described with reference to Figures 11A to 11C. Figures 11A to 11C are diagrams for explaining the method of correcting the actual torque.

[0092] FIG. 11A shows a graph showing the relationship between running resistance and vehicle speed. The horizontal axis of the graph represents vehicle speed, and the vertical axis represents running resistance. Running resistance can be correlated with actual torque. The solid line represents actual torque when the following vehicle runs independently without following the leading vehicle. The dashed line represents actual torque recorded when the following vehicle runs at the first target torque. Both running resistances change exponentially with vehicle speed.

[0093] 11B shows a graph showing the relationship between grade resistance and road gradient. The horizontal axis of the graph represents grade, and the vertical axis represents grade resistance (Rg). Grade resistance (Rg) can be correlated with actual torque.

[0094] 11C shows a graph showing the relationship between steering resistance (Rsteer) and steering angle. The horizontal axis of the graph represents steering angle, and the vertical axis represents steering resistance (Rsteer). The steering resistance (Rsteer) can be correlated with the actual torque.

[0095] The vehicle control device 300 may calculate a new actual torque by subtracting the gradient resistance change (ΔRg) and steering resistance change (ΔRsteer) from the running resistance (Rspd), i.e., actual torque, when the following vehicle's speed, gradient, and steering angle are based on, for example, a following vehicle speed of 100 km / h, a gradient of 0%, and a steering angle of 0°.

[0096] Specifically, as shown in the following equation (1), a value obtained by subtracting ΔRg and ΔRsteer from Rspd (converted motor torque: Tspd) may be calculated as a new actual torque for setting the specific inter-vehicle distance. The converted motor torque may be interpreted as the actual torque after correcting the actual torque.

[0097] Converted motor torque (Tspd) = Rspd - ΔRg - ΔRsteer (1)

[0098] The torque recording unit 10 may record the calculated Tspd as the actual torque shown in Figures 6 to 10. This may improve the accuracy of the specific inter-vehicle distance (optimum inter-vehicle distance) at which the traveling energy consumption of the following vehicle is minimum or close to minimum.

[0099] (Another Operation Example 1) Next, an operation when correcting the lateral deviation amount of a following vehicle will be described with reference to Figures 12 and 13. Figure 12 is a flowchart for explaining the operation of the vehicle control device when correcting the lateral deviation amount. Figure 13 is a diagram showing the following vehicle before and after the lateral deviation amount is corrected. The flowchart shown in Figure 12 differs from the flowchart shown in Figure 4 in that the processing of steps S20 to S22 is added between steps S2 and S3.

[0100] If the vehicle speed exceeds the specific vehicle speed (step S2: YES), in step S20, the lateral deviation amount corrector 12 determines whether the lateral deviation amount is less than a specific range (specific amount Y).

[0101] 13, if the lateral deviation amount exceeds the specific amount Y (step S20: NO), the lateral deviation amount correction unit 12 may adjust the steering amount of the following vehicle until the lateral deviation amount becomes less than the specific amount Y. Specifically, the lateral deviation amount correction unit 12 may calculate the steering angle correction amount in step S21, and instruct the EPS 104 on the operation amount based on the calculated steering angle correction amount in step S22.

[0102] 13 , when the lateral deviation amount becomes less than the specific amount Y (step S20: YES), the lateral deviation amount correction unit 12 may output information indicating that the lateral deviation amount is within a specific range. When the low-torque exploration traveling is permitted in step 3 with this information being output, the vehicle control device 300 may set a target speed for performing the low-torque exploration traveling in step S4.

[0103] (Another operation example 2) Next, referring to Figures 15 and 16, we will explain the operation when a specific vehicle (a vehicle cutting in) is detected during a period in which a following vehicle is performing driving control to follow a leading vehicle while maintaining the aforementioned corresponding inter-vehicle distance.

[0104] Fig. 15 is a flowchart for explaining the operation of the vehicle control device when a cutting-in vehicle is detected. Fig. 16 is a diagram showing the following vehicles before and after the cutting-in vehicle is detected. The flowchart shown in Fig. 15 differs from the flowchart shown in Fig. 4 in that the processing of steps S40 to S44 has been added, and the processing of step S4 and subsequent steps is executed again after step S43.

[0105] In step S40, the vehicle control device 300 may determine whether the following vehicle is traveling to follow the leading vehicle. If the following vehicle is traveling to follow the leading vehicle (step S40: YES), in step S41, the vehicle control device 300 may determine whether a cutting-in vehicle has been detected.

[0106] If a cutting-in vehicle is detected (step S41: YES), in step S42, the vehicle control device 300 updates the vehicle to the preceding vehicle, and in step S43, determines whether the inter-vehicle distance from the cutting-in vehicle (the preceding vehicle after the update) to the following vehicle exceeds a distance equivalent to, for example, twice the safe inter-vehicle distance (corresponding inter-vehicle distance).

[0107] If the inter-vehicle distance is less than twice the safe inter-vehicle distance (corresponding inter-vehicle distance) (step S43: NO), the vehicle control device 300 may correct the first target torque in step S44. Specifically, the vehicle control device 300 may calculate the first target torque so as to move the following vehicle away from the cutting-in vehicle (the updated leading vehicle).

[0108] If the inter-vehicle distance exceeds a distance equivalent to twice the safe inter-vehicle distance (compatible inter-vehicle distance) (step S43: YES), the vehicle control device 300 may again execute the processing from step 4 onwards. That is, the vehicle control device 300 may calculate a first target torque that changes the inter-vehicle distance so that the following vehicle approaches the leading vehicle, that is, a first target torque that closes the inter-vehicle distance. At this time, the vehicle control device 300 may record the actual torque generated based on the first target torque until the inter-vehicle distance reaches the specific inter-vehicle distance. Then, the vehicle control device 300 may set the inter-vehicle distance to a compatible inter-vehicle distance that corresponds to a value within a specific range including the minimum value of the recorded actual torque.

[0109] This makes it possible to minimize the energy consumption of the following vehicle following the cutting-in vehicle.

[0110] (Action, effect) The vehicle control device 300 of the present disclosure calculates a first target torque that changes the inter-vehicle distance from the leading vehicle to the following vehicle, records the actual torque generated based on the first target torque until the inter-vehicle distance reaches a specific inter-vehicle distance, and sets the inter-vehicle distance to a corresponding inter-vehicle distance that corresponds to a value within a specific range including the minimum value of the recorded actual torque.

[0111] This makes it possible to maintain a distance (specific distance) between vehicles at which the torque of the following vehicle is small while the following vehicle is traveling. Therefore, the following vehicle can travel at a distance at which the air resistance generated while traveling is minimum or close to minimum, thereby reducing the traveling energy consumption of the following vehicle.

[0112] The vehicle of the present disclosure may be a vehicle equipped with an internal combustion engine in addition to the motor 103 .

[0113] Furthermore, the vehicle control device 300 of the present disclosure may record the actual torque while adjusting the lateral deviation amount of the following vehicle, and may set the corresponding inter-vehicle distance using, for example, the minimum value of the recorded actual torque. Specifically, for example, when a following vehicle is traveling at the same speed as the leading vehicle while maintaining a constant inter-vehicle distance from the leading vehicle, the vehicle control device 300 may adjust the steering amount so that the lateral deviation amount of the following vehicle falls within the specific range described above. The vehicle control device 300 may record the actual torque detected at this time, and may set the corresponding inter-vehicle distance using, for example, the minimum value of the recorded actual torque.

[0114] Furthermore, the vehicle control device 300 of the present disclosure may record the actual torque when the following vehicle travels away from (moves away from) the leading vehicle, and may set the corresponding inter-vehicle distance using, for example, the minimum value of the recorded actual torque. Specifically, the vehicle control device 300 may calculate a target torque that causes the following vehicle to approach the leading vehicle up to a specific distance where the inter-vehicle distance becomes shorter than the safe inter-vehicle distance (specific inter-vehicle distance). When the following vehicle reaches this specific distance, the vehicle control device 300 may calculate a first target torque that causes the following vehicle to gradually move away from (moves away from) the leading vehicle. The vehicle control device 300 may record the actual torque generated based on the first target torque until, for example, the inter-vehicle distance reaches a distance equivalent to twice the safe inter-vehicle distance. The vehicle control device 300 may then set the corresponding inter-vehicle distance to the inter-vehicle distance using, for example, the minimum value of the recorded actual torque.

[0115] The controller and methods described herein may be implemented by a special-purpose computer having a processor programmed to perform one or more functions embodied in a computer program. Alternatively, the apparatus and methods described herein may be implemented by a special-purpose computer having a processor configured with dedicated hardware logic circuitry. Alternatively, the apparatus and methods described herein may be implemented by one or more special-purpose computers configured by a combination of a processor executing a computer program and one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0116] <Additional Notes> The features of the present invention are as follows.

[0117] (Supplementary Note 1) A vehicle control device comprising: a target torque calculation unit that calculates a first target torque that changes the inter-vehicle distance from a leading vehicle to a following vehicle following the leading vehicle; a torque recording unit that records an actual torque generated based on the first target torque until the inter-vehicle distance reaches a specific inter-vehicle distance to be maintained between the following vehicle and the leading vehicle; and a distance setting unit that sets, as the inter-vehicle distance, a corresponding inter-vehicle distance that corresponds to a value within a specific range including the minimum value of the recorded actual torque.

[0118] (Supplementary Note 2) The vehicle control device according to Supplementary Note 1, wherein, when there is one value when the actual torque changes from decreasing to increasing, the distance setting unit sets the corresponding inter-vehicle distance to that value as a value within the specific range.

[0119] (Appendix 3) The vehicle control device according to appendix 1 or 2, wherein, when there are multiple values ​​when the actual torque changes from decreasing to increasing, the distance setting unit sets the corresponding inter-vehicle distance to one of the multiple values ​​as a value within the specific range.

[0120] (Supplementary Note 4) The vehicle control device according to Supplementary Note 3, wherein the distance setting unit sets the corresponding inter-vehicle distance by setting the lowest value of the plurality of values ​​as a value within the specific range.

[0121] (Supplementary Note 5) The vehicle control device according to Supplementary Note 3, wherein, when the plurality of values ​​are equal, the distance setting unit sets the corresponding inter-vehicle distance as a value within the specific range, the value corresponding to the position where the following vehicle is farthest from the preceding vehicle, among the plurality of values.

[0122] (Appendix 6) The vehicle control device described in any one of Appendices 1 to 5, wherein the distance setting unit compares the actual torque at a first point in time with the actual torque at a second point in time prior to the first point in time, and sets the corresponding inter-vehicle distance by setting the actual torque whose value is smaller as a result of the comparison to a value within the specific range.

[0123] (Supplementary Note 7) The vehicle control device according to any one of Supplementary Notes 1 to 6, wherein the target torque calculation unit calculates a second target torque for maintaining the corresponding inter-vehicle distance, and outputs the second target torque instead of the first target torque.

[0124] (Supplementary Note 8) The vehicle control device according to any one of Supplementary Notes 1 to 7, wherein the distance setting unit sets the corresponding inter-vehicle distance corresponding to the minimum value.

[0125] (Appendix 9) The vehicle control device according to any one of Appendices 1 to 8, wherein the torque recording unit records the actual torque after correcting the actual torque based on at least one of the vehicle speed of the following vehicle, the gradient of the following vehicle, and the steering angle of the following vehicle.

[0126] (Supplementary Note 10) A vehicle control device as described in any one of Supplementary Notes 1 to 9, comprising a lateral deviation amount correction unit that adjusts the steering amount of the following vehicle based on image information including the preceding vehicle imaged by an imaging means, thereby keeping the relative lateral deviation amount of the following vehicle with respect to the preceding vehicle within a specific range, and the distance setting unit sets the corresponding inter-vehicle distance to the inter-vehicle distance when the deviation amount falls within the specific range.

[0127] (Appendix 11) A vehicle control device described in any one of Appendices 1 to 10, wherein the distance setting unit: when the specific inter-vehicle distance is a safe inter-vehicle distance that increases the possibility of avoiding a collision of the following vehicle with the preceding vehicle, if the corresponding inter-vehicle distance is shorter than the safe inter-vehicle distance, sets the safe inter-vehicle distance instead of the corresponding inter-vehicle distance; and when the corresponding inter-vehicle distance is longer than the safe inter-vehicle distance, sets the corresponding inter-vehicle distance instead of the safe inter-vehicle distance.

[0128] (Appendix 12) The vehicle control device according to Appendix 11, wherein the torque recording unit further records an actual torque generated based on the first target torque when the following vehicle approaches the leading vehicle up to a specific distance where the inter-vehicle distance becomes shorter than the safe inter-vehicle distance.

[0129] (Supplementary Note 13) The vehicle control device according to Supplementary Note 11, further comprising a safe inter-vehicle distance calculation unit that calculates the safe inter-vehicle distance based on at least one of a vehicle speed of the following vehicle, a vehicle weight estimated at the time of starting of the following vehicle, and a friction coefficient of a road surface on which the following vehicle is traveling.

[0130] (Appendix 14) A vehicle control device as described in any one of Appendices 1 to 13, wherein the target torque calculation unit calculates the first target torque that makes the corresponding inter-vehicle distance longer than the specific inter-vehicle distance when, during a period in which the following vehicle is performing driving control to follow the leading vehicle while maintaining the corresponding inter-vehicle distance, the target torque calculation unit detects that a specific vehicle has cut in between the leading vehicle and the following vehicle, causing the corresponding inter-vehicle distance to become shorter than the specific inter-vehicle distance; the torque recording unit records the actual torque generated based on the first target torque until the inter-vehicle distance reaches the specific inter-vehicle distance between the following vehicle and the specific vehicle; and the distance setting unit sets the corresponding inter-vehicle distance to a value within a specific range including the minimum value of the recorded actual torque.

[0131] (Supplementary Note 15) The vehicle control device according to Supplementary Note 1, wherein the distance setting unit sets the corresponding inter-vehicle distance during a period in which a specific function is being executed.

[0132] (Supplementary Note 16) A vehicle control program that causes at least one processor to execute processing including: calculating a first target torque that changes the inter-vehicle distance from a leading vehicle to a following vehicle following the leading vehicle; recording an actual torque generated based on the first target torque until the inter-vehicle distance reaches a specific inter-vehicle distance to be maintained between the following vehicle and the leading vehicle; and setting the inter-vehicle distance to a corresponding inter-vehicle distance that corresponds to a value within a specific range including the minimum value of the recorded actual torque.

[0133] (Supplementary Note 17) A vehicle control method in which at least one processor executes processing including: calculating a first target torque that changes the inter-vehicle distance from a leading vehicle to a following vehicle following the leading vehicle; recording an actual torque generated based on the first target torque until the inter-vehicle distance reaches a specific inter-vehicle distance to be maintained between the following vehicle and the leading vehicle; and setting the inter-vehicle distance to a corresponding inter-vehicle distance that corresponds to a value within a specific range including the minimum value of the recorded actual torque.

[0134] The above describes one embodiment of the present invention, but the present invention is not limited to the above, and it goes without saying that the present invention can be implemented in various modified forms within the scope of the gist of the present invention.

Claims

1. A vehicle control device (300) comprising: a target torque calculation unit (16) that calculates a first target torque that changes the inter-vehicle distance from a leading vehicle to a following vehicle following the leading vehicle; a torque recording unit (10) that records an actual torque generated based on the first target torque until the inter-vehicle distance reaches a specific inter-vehicle distance to be maintained between the following vehicle and the leading vehicle; and a distance setting unit (11) that sets, to the inter-vehicle distance, a corresponding inter-vehicle distance corresponding to a value within a specific range including a minimum value of the recorded actual torque.

2. A vehicle control device as described in claim 1, wherein, when there is one value when the actual torque changes from decreasing to increasing, the distance setting unit sets the corresponding inter-vehicle distance to the corresponding inter-vehicle distance as a value within the specific range.

3. A vehicle control device as described in claim 1, wherein, when there are multiple values ​​when the actual torque changes from decreasing to increasing, the distance setting unit sets the corresponding inter-vehicle distance to one of the multiple values ​​as a value within the specific range.

4. A vehicle control device according to claim 3, wherein the distance setting unit sets the corresponding inter-vehicle distance as the inter-vehicle distance by taking the lowest value among the plurality of values ​​as a value within the specific range.

5. A vehicle control device as described in claim 3, wherein, when a plurality of said values ​​are equal, the distance setting unit sets the corresponding inter-vehicle distance as the value within the specific range that corresponds to the position where the following vehicle is farthest from the leading vehicle, among the plurality of said values.

6. A vehicle control device as described in claim 1, wherein the distance setting unit compares the actual torque at a first point in time with the actual torque at a second point in time prior to the first point in time, and sets the corresponding inter-vehicle distance as the inter-vehicle distance by setting the actual torque whose value is smaller as a value within the specific range as a result of the comparison.

7. The vehicle control device according to claim 1, wherein the target torque calculation unit calculates a second target torque for maintaining the corresponding inter-vehicle distance, and outputs the second target torque instead of the first target torque.

8. The vehicle control device according to claim 1, wherein the distance setting unit sets the corresponding inter-vehicle distance corresponding to the minimum value as the inter-vehicle distance.

9. The vehicle control device according to claim 1, wherein the torque recording unit records the actual torque after correcting the actual torque based on at least one of the vehicle speed of the following vehicle, the gradient which is the inclination of the following vehicle, and the steering angle of the following vehicle.

10. A vehicle control device as described in claim 1, further comprising a lateral deviation correction unit (12) that adjusts the steering amount of the following vehicle based on image information including the preceding vehicle imaged by an imaging means, thereby keeping the relative lateral deviation amount of the following vehicle with respect to the preceding vehicle within a specific range, and wherein the distance setting unit sets the corresponding following distance to the following distance when the deviation amount falls within the specific range.

11. A vehicle control device as described in claim 1, wherein the distance setting unit: when the specific inter-vehicle distance is a safe inter-vehicle distance that increases the possibility of avoiding a collision of the following vehicle with the preceding vehicle, when the corresponding inter-vehicle distance is shorter than the safe inter-vehicle distance, sets the vehicle distance to the safe distance instead of the corresponding inter-vehicle distance; and when the corresponding inter-vehicle distance is longer than the safe inter-vehicle distance, sets the vehicle distance to the corresponding inter-vehicle distance instead of the safe distance.

12. A vehicle control device as described in claim 11, wherein the torque recording unit further records an actual torque generated based on the first target torque when the following vehicle approaches the leading vehicle up to a specific distance where the vehicle distance becomes shorter than the safe vehicle distance.

13. A vehicle control device as described in claim 11, further comprising a safe vehicle distance calculation unit (14) that calculates the safe vehicle distance based on at least one of the vehicle speed of the following vehicle, the vehicle weight estimated when the following vehicle starts moving, and the friction coefficient of the road surface on which the following vehicle is traveling.

14. A vehicle control device as described in claim 1, wherein when the corresponding inter-vehicle distance becomes shorter than the specific inter-vehicle distance due to detection that a specific vehicle has cut in between the leading vehicle and the following vehicle during a period in which the following vehicle is performing driving control to follow the leading vehicle while maintaining the corresponding inter-vehicle distance, the target torque calculation unit calculates the first target torque that makes the corresponding inter-vehicle distance longer than the specific inter-vehicle distance, the torque recording unit records the actual torque generated based on the first target torque until the inter-vehicle distance reaches the specific inter-vehicle distance between the following vehicle and the specific vehicle, and the distance setting unit sets the corresponding inter-vehicle distance to a value within a specific range including a minimum value of the recorded actual torque.

15. The vehicle control device according to claim 1, wherein the distance setting unit sets the corresponding inter-vehicle distance to the inter-vehicle distance during a period in which a specific function is being executed.

16. A vehicle control program (2a) that causes at least one processor (3) to execute processes including: calculating a first target torque that changes the inter-vehicle distance from a leading vehicle to a following vehicle following the leading vehicle; recording an actual torque generated based on the first target torque until the inter-vehicle distance reaches a specific inter-vehicle distance between the following vehicle and the leading vehicle; and setting, as the inter-vehicle distance, a corresponding inter-vehicle distance that corresponds to a value within a specific range including the minimum value of the recorded actual torque.

17. A vehicle control method in which at least one processor executes processes including: calculating a first target torque that changes the inter-vehicle distance from a leading vehicle to a following vehicle following the leading vehicle; recording an actual torque generated based on the first target torque until the inter-vehicle distance reaches a specific inter-vehicle distance between the following vehicle and the leading vehicle; and setting, as the inter-vehicle distance, a corresponding inter-vehicle distance that corresponds to a value within a specific range including the minimum value of the recorded actual torque.