Vehicle driving assistance device

Abstract

The invention provides a vehicle driving assistance device capable of suppressing an increase in energy consumption for driving a host vehicle when follow-up travel control is executed. A vehicle driving assistance device (10) executes: follow-up travel control for causing a host vehicle (100) to travel by autonomously switching between power travel control for causing the host vehicle to power travel and coasting travel control for causing the host vehicle to coasting travel so as to maintain the inter-vehicle distance between a preceding vehicle (200) and the host vehicle (100) within a predetermined inter-vehicle distance range; and a vehicle speed control for causing the vehicle to travel by autonomously switching between the power travel control and the coasting travel control so as to maintain the vehicle speed of the vehicle within a prescribed vehicle speed range. The vehicle driving assistance device executes following travel control when the vehicle speed of the preceding vehicle is equal to or less than a predetermined vehicle speed, and executes vehicle speed control when the vehicle speed of the preceding vehicle is greater than the predetermined vehicle speed.

Description

Technical Field

[0001] The present invention relates to a vehicle driving assistance device. Background Art

[0002] A vehicle driving assistance device is known that performs following driving control, autonomously switching between power driving control (where the vehicle is powered) and inertial driving control (where the vehicle is coasting) to drive the vehicle so that the distance between the vehicle ahead, i.e., the inter-vehicle distance, is maintained within a certain range (see, for example, Patent Document 1). This vehicle driving assistance device utilizes inertial driving control to reduce energy consumption for driving the vehicle. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-95320 Summary of the Invention

[0004] However, if the preceding vehicle's speed is high during the execution of the aforementioned following control, the distance between the vehicle and the preceding vehicle increases rapidly during inertial control. Consequently, the control for the preceding vehicle's travel quickly switches from inertial control to power travel control. Consequently, frequent switching from inertial control to power travel increases the energy consumed by the preceding vehicle.

[0005] An object of the present invention is to provide a vehicle driving assistance device that can suppress an increase in energy consumption for traveling a host vehicle when follow-up traveling control is executed.

[0006] A vehicle driving assistance device according to the present invention includes a control device that performs: following travel control, which autonomously switches between power travel control, which causes the host vehicle to travel, and inertial travel control, which causes the host vehicle to travel, so as to maintain the distance between the host vehicle and a preceding vehicle, i.e., the inter-vehicle distance, within a predetermined inter-vehicle distance range; and speed control, which autonomously switches between power travel control and inertial travel control, so as to maintain the host vehicle's speed within a predetermined speed range. The control device is configured to perform following travel control when the preceding vehicle's speed is below a predetermined speed, and to perform speed control when the preceding vehicle's speed exceeds the predetermined speed.

[0007] As previously described, if the leading vehicle's speed is high during following control, the distance between the vehicles increases rapidly when the host vehicle is coasting using inertial control. This causes the host vehicle's control to quickly switch from inertial control to powered control. Consequently, frequent switching from inertial control to powered control increases the energy consumed by the host vehicle.

[0008] According to the vehicle driving assistance device involved in the present invention, when the speed of the vehicle traveling ahead is high, the vehicle is driven by speed control, thereby suppressing the frequent switching from inertial driving control to power driving control. As a result, the increase in energy consumption used to drive the vehicle can be suppressed.

[0009] In the vehicle driving assistance device according to the present invention, the predetermined vehicle speed is, for example, a vehicle speed obtained by subtracting a value corresponding to the width of the predetermined vehicle speed range from an upper limit value of the predetermined vehicle speed range.

[0010] The vehicle driving assistance device of the present invention determines whether to execute following driving control or vehicle speed control according to the width of the predetermined vehicle speed range. Therefore, it is possible to execute vehicle speed control in a more appropriate manner while suppressing an increase in energy consumption for driving the vehicle.

[0011] In the vehicle driving support device according to the present invention, the predetermined vehicle speed is, for example, a vehicle speed that is equal to or lower than an average vehicle speed of the host vehicle when the host vehicle is traveling by the vehicle speed control.

[0012] The vehicle driving assistance device according to the present invention uses the average speed of the vehicle during travel by speed control to determine whether to execute following travel control or speed control. Therefore, speed control can be executed more appropriately while suppressing an increase in energy consumption for traveling the vehicle.

[0013] The components of the present invention are not limited to the embodiments of the present invention described below with reference to the drawings. Other objects, other features, and advantages of the present invention can be easily understood from the description of the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a diagram showing a vehicle driving assistance device according to an embodiment of the present invention. Figure 2 This is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention. Figure 3 This is a diagram showing a situation where there is a vehicle traveling ahead of the host vehicle. DETAILED DESCRIPTION

[0015] Hereinafter, a vehicle driving assistance device according to an embodiment of the present invention will be described with reference to the drawings. Figure 1 The vehicle driving assistance device 10 involved in an embodiment of the present invention is shown. The vehicle driving assistance device 10 is mounted on the vehicle 100. Hereinafter, the vehicle driving assistance device 10 will be described by taking the case where the operator of the vehicle 100 is a person who rides in the vehicle 100 and drives the vehicle 100 (i.e., the driver of the vehicle 100) as an example. However, the operator of the vehicle 100 may also be a person who does not ride in the vehicle 100 but drives the vehicle 100 remotely (i.e., the remote operator of the vehicle 100). In addition, the present invention may also be applied to a vehicle that can be driven only by automatic driving control, and may also be applied to a vehicle that can be driven by manual driving operation and automatic driving control.

[0016] like Figure 1 As shown, the vehicle driving assistance device 10 includes an ECU (electronic control unit) 90 as a control device. The ECU 90 includes a microcomputer as its main component. The microcomputer includes a CPU, storage media such as ROM, RAM, and non-volatile memory, as well as interfaces, etc. The CPU implements various functions by executing instructions, programs, or routines stored in the storage media. In particular, in this example, the vehicle driving assistance device 10 stores programs that implement the various controls executed by the vehicle driving assistance device 10 in the storage medium.

[0017] In this example, the vehicle driving assistance device 10 includes only one ECU 90. However, the vehicle driving assistance device 10 may also include multiple ECUs, with each ECU sharing the functions of the vehicle driving assistance device 10 described below. Furthermore, the vehicle driving assistance device 10 may also be configured so that the program stored in the storage medium can be updated (upgraded) via wireless communication (e.g., Internet communication) with an external device.

[0018] like Figure 1 As shown, the vehicle 100 is equipped with a drive device 20 , a brake device 30 , a driving support operator 40 , a vehicle speed detection device 50 , and a peripheral information detection device 60 .

[0019] The drive device 20 is a device that generates driving force applied to the host vehicle 100 (particularly, the drive wheels of the host vehicle 100). In this example, the drive device 20 includes an internal combustion engine 21 and a motor 22. The drive device 20 is electrically connected to the ECU 90. The vehicle driving assistance device 10 can control the driving force applied to the host vehicle 100 by controlling the operation of the drive device 20 (i.e., the internal combustion engine 21 and the motor 22).

[0020] The brake device 30 is a device that applies braking force to the vehicle 100 (particularly, the wheels of the vehicle 100). The brake device 30 is, for example, a hydraulic brake device. The brake device 30 is electrically connected to the ECU 90. The vehicle driving assistance device 10 can control the braking force applied to the vehicle 100 by controlling the operation of the brake device 30.

[0021] The driving assistance operator 40 is an instrument operated by the driver of the vehicle 100 to request execution of the follow-up travel control (described later) or to request termination of the follow-up travel control. The driving assistance operator 40 is electrically connected to the ECU 90. In this example, if the driving assistance operator 40 is operated while the follow-up travel control is not being executed, the vehicle driving assistance device 10 determines that execution of the follow-up travel control has been requested. On the other hand, if the driving assistance operator 40 is operated while the follow-up travel control is being executed, the vehicle driving assistance device 10 determines that termination of the follow-up travel control has been requested.

[0022] The vehicle speed detection device 50 detects the traveling speed of the host vehicle 100. The vehicle speed detection device 50 includes, for example, wheel speed sensors installed on each wheel of the host vehicle 100. The vehicle speed detection device 50 is electrically connected to the ECU 90. The vehicle driving assistance device 10 obtains the traveling speed of the host vehicle 100 from the vehicle speed detection device 50 as the host vehicle speed Vego.

[0023] The surrounding information detection device 60 detects information about the surroundings of the host vehicle 100. In this example, the surrounding information detection device 60 includes an electromagnetic wave sensor 61 and an image sensor 62. The electromagnetic wave sensor 61 and the image sensor 62 are electrically connected to the ECU 90. The electromagnetic wave sensor 61 is, for example, a radar sensor such as a millimeter-wave radar. The vehicle driving assistance device 10 uses the electromagnetic wave sensor 61 to obtain information about objects around the host vehicle 100 as surrounding information IS. Furthermore, the image sensor 62 is, for example, a camera sensor. The vehicle driving assistance device 10 uses the image sensor 62 to obtain image information about the surroundings of the host vehicle 100 as surrounding information IS.

[0024] <Operation of vehicle driving assistance system> Next, the operation of the vehicle driving assistance device 10 will be described. The vehicle driving assistance device 10 is configured to execute the following operation at predetermined time intervals: Figure 2 The routine shown executes following travel control or vehicle speed control as automatic driving control when predetermined conditions are satisfied.

[0025] As a follow-up driving control, Figure 3When the preceding vehicle 200 exists, the host vehicle 100 is driven by autonomously or automatically switching between power running control and inertial running control so as to maintain the inter-vehicle distance D within the predetermined inter-vehicle distance range RD.

[0026] Power running control applies driving force from the drive unit 20 to the vehicle 100, causing the vehicle 100 to run under power. Specifically, power running control is optimal power running control, which applies driving force from the drive unit 20 to the vehicle 100 while operating the drive unit 20 at optimal energy efficiency, causing the vehicle 100 to run under power. Meanwhile, coasting control disconnects the drive unit 20 from the drive wheels of the vehicle 100, reducing the driving force applied from the drive unit 20 to zero, causing the vehicle 100 to coast.

[0027] The preceding vehicle 200 is another vehicle traveling in the lane in which the host vehicle 100 is traveling, and is located within a predetermined distance in front of the host vehicle 100. Furthermore, the inter-vehicle distance D is the distance between the host vehicle 100 and the preceding vehicle 200. The vehicle driving assistance device 10 determines whether the preceding vehicle 200 exists based on the surrounding information IS. Furthermore, the vehicle driving assistance device 10 obtains the inter-vehicle distance D based on the surrounding information IS.

[0028] In this example, the specified inter-vehicle distance range RD is defined as a range with the set inter-vehicle distance Dset as the lower limit Dlower and a distance greater than the set inter-vehicle distance Dset by a specified width WD (or a specified value) as the upper limit Dupper. The set inter-vehicle distance Dset is set by the driver. The specified width WD can be a fixed value independent of the vehicle speed Vego, or it can vary depending on the vehicle speed Vego. Specifically, it can be a value that increases as the vehicle speed Vego increases.

[0029] During the execution of the following travel control, if the inter-vehicle distance D becomes longer than the upper limit value Dupper of the predetermined inter-vehicle distance range RD, the vehicle driving assistance device 10 initiates the power travel control. On the other hand, during the execution of the following travel control, if the inter-vehicle distance D becomes shorter than the lower limit value Dlower of the predetermined inter-vehicle distance range RD, the vehicle driving assistance device 10 initiates the inertial travel control.

[0030] Furthermore, in this example, when the vehicle speed Vego increases to the set vehicle speed Vset during the follow-up driving control, the vehicle driving assistance device 10 autonomously or automatically controls the operation of the drive device 20 and the brake device 30 to drive the vehicle 100 so as to maintain the vehicle speed Vego at the set vehicle speed Vset. The set vehicle speed Vset is set by the driver.

[0031] On the other hand, the vehicle speed control is a control for running the host vehicle 100 by autonomously or automatically switching between power running control and inertial running control so as to maintain the host vehicle speed Vego within a predetermined vehicle speed range RV.

[0032] In this example, the prescribed vehicle speed range RV is defined as a range with the set vehicle speed Vset as the upper limit Vupper and a vehicle speed lower than the set vehicle speed Vset by a prescribed width WV (or a prescribed value) as the lower limit Vlower. As described above, the set vehicle speed Vset is the vehicle speed set by the driver. The prescribed width WV can be a fixed value independent of the vehicle speed Vego, or it can be a different value corresponding to the vehicle speed Vego. Specifically, it can be a value that increases as the vehicle speed Vego increases.

[0033] During vehicle speed control, if the vehicle speed Vego exceeds the upper limit Vupper of the predetermined vehicle speed range RV, the vehicle driving assistance device 10 initiates inertial running control. On the other hand, during vehicle speed control, if the vehicle speed Vego falls below the lower limit Vlower of the predetermined vehicle speed range RV, the vehicle driving assistance device 10 initiates power running control.

[0034] If it is at a predetermined timing, the vehicle driving assistance device 10 Figure 2 The routine shown starts processing at step S200, and the process proceeds to step S205, where it is determined whether a driving assistance request condition C1 is satisfied. The driving assistance request condition C1 is a condition that the driver has requested execution of the follow-up travel control.

[0035] When the determination in step S205 is “YES”, the vehicle driving assistance device 10 advances the process to step S210 to determine whether or not the preceding vehicle 200 exists.

[0036] If the determination in step S210 is "YES," the vehicle driving assistance device 10 proceeds to step S215 to determine whether the preceding vehicle speed condition C2 is satisfied. The preceding vehicle speed condition C2 is a condition that enables the host vehicle 100 to follow the preceding vehicle 200 through following travel control. In this example, the preceding vehicle speed condition C2 is a condition that the preceding vehicle speed Vpre is equal to or less than a predetermined speed Vth. The preceding vehicle speed Vpre is the speed of the preceding vehicle 200. The vehicle driving assistance device 10 obtains the preceding vehicle speed Vpre based on the surrounding information IS and the host vehicle speed Vego.

[0037] The prescribed vehicle speed Vth can be any vehicle speed that is appropriately set in order to obtain the effects described below. In this example, the prescribed vehicle speed Vth is the value obtained by subtracting the value ΔV corresponding to the width WV of the prescribed vehicle speed range RV from the upper limit value Vupper of the prescribed vehicle speed range RV (Vth=Vupper-ΔV). In particular, in this example, the value ΔV corresponding to the width WV of the prescribed vehicle speed range RV is the value obtained by multiplying the width WV of the prescribed vehicle speed range RV by a prescribed coefficient k (ΔV=WV·k). In this example, the prescribed coefficient k is a value less than "1". The prescribed coefficient k is set so that the prescribed vehicle speed Vth becomes less than the average vehicle speed Vave of the vehicle 100 when the vehicle 100 is traveling by speed control (Vth≤Vave). Alternatively, the prescribed coefficient k is set, for example, so that the prescribed vehicle speed Vth becomes less than the vehicle speed Vcenter in the middle of the prescribed vehicle speed range RV (Vth≤Vcenter).

[0038] If the determination in step S215 is "YES", the vehicle driving assistance device 10 advances the process to step S220 and executes the follow-up driving control. Next, the vehicle driving assistance device 10 advances the process to step S295 and temporarily ends the process of this routine.

[0039] On the other hand, if the determination in step S215 is "No," the vehicle driving assistance device 10 proceeds to step S225 and executes vehicle speed control. That is, even when a leading vehicle 200 is present and a request for follow-up driving control is made, the vehicle driving assistance device 10 executes vehicle speed control if the leading vehicle speed Vpre is greater than the predetermined vehicle speed Vth. The vehicle driving assistance device 10 then proceeds to step S295, temporarily terminating the processing of this routine.

[0040] If a "No" is determined in step S205 or step S210, the vehicle driving assistance device 10 proceeds to step S230 and, if following travel control or vehicle speed control is currently being executed, terminates the following travel control or vehicle speed control. The vehicle driving assistance device 10 then proceeds to step S295 to temporarily terminate the processing of this routine.

[0041] The above is the operation of the vehicle driving assistance device 10 .

[0042] When the speed Vpre of the preceding vehicle is high during the execution of following travel control, the inter-vehicle distance D rapidly increases when the host vehicle 100 is coasting under inertial travel control. Therefore, the control for driving the host vehicle 100 is rapidly switched from inertial travel control to power travel control. As a result, frequent switching from inertial travel control to power travel control increases the energy consumption for driving the host vehicle 100.

[0043] According to the vehicle driving assistance device 10, since the vehicle 100 is driven by vehicle speed control when the speed Vpre of the vehicle traveling ahead is large, the frequent switching from inertial driving control to power driving control can be suppressed. As a result, the increase in energy consumption used to drive the vehicle 100 can be suppressed.

[0044] In addition, the present invention is not limited to the above-described embodiment, and various modifications can be adopted within the scope of the present invention. Description of the label

[0045] 10 ...Vehicle driving assistance device, 20 ...Driving device, 30 ...Braking device, 40 ...Driving assistance operation unit, 50 ...Vehicle speed detection device, 60 ...Peripheral information detection device, 90 ...ECU, 100 ...Own vehicle, 200 ...Vehicle traveling ahead

Claims

1. A vehicle driving assistance device comprising a control device, The control device performs: following driving control to drive the host vehicle by autonomously switching between power driving control for driving the host vehicle by power and inertial driving control for driving the host vehicle by inertial driving in such a manner that the distance between the host vehicle and the preceding vehicle, i.e., the inter-vehicle distance, is maintained within a prescribed inter-vehicle distance range; and vehicle speed control to drive the host vehicle by autonomously switching between the power driving control and the inertial driving control in such a manner that the speed of the host vehicle is maintained within a prescribed vehicle speed range. In the vehicle driving assistance device, The control device is configured as follows: When the speed of the preceding vehicle is below a predetermined speed, the following travel control is executed. The vehicle speed control is executed when the vehicle speed of the preceding vehicle is greater than the prescribed vehicle speed.

2. The vehicle driving assistance device according to claim 1, wherein: The prescribed vehicle speed is a vehicle speed obtained by subtracting a value corresponding to the width of the prescribed vehicle speed range from an upper limit value of the prescribed vehicle speed range.

3. The vehicle driving assistance device according to claim 1 or 2, wherein: The predetermined vehicle speed is a vehicle speed that is equal to or lower than an average vehicle speed of the host vehicle when the host vehicle is traveling by the vehicle speed control.

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