Driving assistance device, driving assistance method, and program

Abstract

To improve the convenience of an operation up to an ACC start or a restart from a vehicle stop state.SOLUTION: A drive support system comprises: a control part 11 for performing at least either of constant-speed traveling control for making an own vehicle 100 travel at a constant speed on the basis of a situation around the own vehicle 100, and following traveling control for making the own vehicle 100 travel following a preceding vehicle 200, and stopping the traveling control during a stop of the own vehicle 100; detection parts 43, 13 for detecting the release of a brake pedal by an occupant of the own vehicle 100; and acceptance parts 60, 13 which can accept a support requirement from the occupant. The control part 11 detects the release of the brake pedal by the detection parts 43, 13 during the stop of the own vehicle 100, and when the acceptance parts 60, 13 accept the support requirement, starts or restarts the traveling control.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a driving assistance device, a driving assistance method, and a program, and in particular to a technology of adaptive cruise control (ACC). [Background technology]

[0002] Conventionally, there is known a driving assistance device capable of executing ACC (see, for example, Patent Document 1). ACC is a control that performs constant speed traveling control to make the host vehicle travel at a constant speed at a target vehicle speed when there is no preceding vehicle ahead of the host vehicle, and performs follow-up traveling control to make the host vehicle follow the preceding vehicle at a speed equal to or lower than the target vehicle speed when there is a preceding vehicle ahead. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-010371 Summary of the Invention

[0004] In vehicles equipped with an electric parking brake (EPB), which is an electric stop-holding mechanism, the EPB can be activated to hold the vehicle in a stopped state. Therefore, in vehicles equipped with an EPB, the ACC can be enabled even when the vehicle is stopped, and the driver can start or resume the ACC early by depressing the accelerator pedal when starting the vehicle.

[0005] On the other hand, in vehicles that are not equipped with EPB, there is a limit to the braking force that can be applied to the wheels from the system while the vehicle is stopped, and if ACC is enabled while the vehicle is stopped, there is a possibility that safety cannot be guaranteed if the driver gets out of the vehicle, etc. For this reason, in vehicles that are not equipped with EPB, it is common to disable ACC while the vehicle is stopped and leave it up to the driver to operate the brakes to keep the vehicle stopped.

[0006] In such vehicles without an EPB, the driver must release the brake pedal, operate the accelerator to increase the vehicle speed to a predetermined speed, and then turn on the start switch before starting or restarting ACC from a stopped state, which can be inconvenient for the driver. In other words, there is room for improvement in the convenience of the operations required to start or restart ACC from a stopped state.

[0007] The present disclosure has been made to solve the above-mentioned problems. That is, one of the objects of the present disclosure is to improve the convenience of operations from a vehicle stopped state to starting or restarting ACC.

[0008] The device of the present disclosure comprises: A driving assistance device (1) for a vehicle (100), a control unit (11) that executes at least one of a constant speed travel control for causing the host vehicle (100) to travel at a constant speed and a follow-up travel control for causing the host vehicle (100) to follow a preceding vehicle (200) based on the situation around the host vehicle (100), and stops the travel control while the host vehicle (100) is stopped; a detection unit (43, 13) for detecting the release of a brake pedal by an occupant of the vehicle (100); a reception unit (60, 13) capable of receiving a request for assistance from the occupant, The control unit (11) is characterized in that, when the detection unit (43, 13) detects the release of the brake pedal while the host vehicle (100) is stopped and the reception unit (60, 13) receives the assistance request, the control unit (11) starts or resumes the driving control.

[0009] The method of the present disclosure comprises: A driving assistance method for a vehicle (100), Based on the situation around the host vehicle (100), at least one of constant speed travel control for causing the host vehicle (100) to travel at a constant speed and follow-up travel control for causing the host vehicle (100) to follow up a preceding vehicle is executed, and the travel control is stopped while the host vehicle (100) is stopped; The driving control is started or resumed when the release of the brake pedal by the occupant of the vehicle (100) is detected while the vehicle (100) is stopped and an assistance request is received from the occupant.

[0010] The program of the present disclosure is A computer of a driving assistance device (1) of a vehicle (100) Based on the situation around the host vehicle (100), at least one of constant speed travel control for causing the host vehicle (100) to travel at a constant speed and follow-up travel control for causing the host vehicle (100) to follow up a preceding vehicle is executed, and the travel control is stopped while the host vehicle (100) is stopped; The system is characterized in that when it detects that the brake pedal has been released by an occupant of the vehicle (100) while the vehicle (100) is stopped, and receives an assistance request from the occupant, it executes a process to start or resume the driving control.

[0011] According to the above configuration, when the driver starts the stopped vehicle (100) using the cruise control (ACC), the driver can quickly start or resume the cruise control (ACC) by simply releasing the brake pedal and turning on the ACC switch (61, 64) while the vehicle (100) is stopped. That is, the accelerator operation required to start or resume the cruise control (ACC) in a conventional vehicle not equipped with an EPB, specifically, the operation of depressing the accelerator pedal to increase the vehicle speed (V) to the lower limit vehicle speed (Vs), is no longer necessary. This effectively prevents the driver from feeling annoyed and reliably improves operational convenience. Furthermore, the cruise control (ACC) can be quickly started or resumed before the vehicle speed (V) reaches the lower limit vehicle speed (Vs), thereby improving drivability.

[0012] In another aspect of the present disclosure, The vehicle control system further includes a determination unit (12) that determines whether the vehicle (100) is in a start-ready state where the vehicle (100) can start moving forward based on a situation around the vehicle (100) while the vehicle (100) is stopped, After the determination unit (12) determines that the vehicle is in the start-possible state, the detection unit (43, 13) detects that the brake pedal has been released, and the reception unit (60, 13) receives the assistance request, the control unit (11) starts or resumes the driving control.

[0013] According to this aspect, the control unit (11) starts or resumes the ACC cruise control in a state where the vehicle (100) can reliably start moving forward. This prevents the ACC cruise control from stopping in a short time, for example, when a preceding vehicle stops immediately after the ACC cruise control is started, and effectively prevents the driver from feeling uncomfortable.

[0014] In another aspect of the present disclosure, a braking force control unit (15) that, when the host vehicle (100) stops on an uphill road, executes braking force maintaining control to maintain a braking force for maintaining the host vehicle (100) in a stopped state, The braking force control unit (15) maintains the braking force even if the detection unit (43, 13) detects that the brake pedal is released while the braking force maintenance control is being executed, and releases the braking force when the reception unit (60, 13) receives the assistance request.

[0015] According to this aspect, when the cruise control (ACC) is started or resumed from a state in which the vehicle (100) is stopped on an uphill road, even if the driver releases the brake pedal, braking force is applied to the wheels by the braking force maintenance control until the driver turns on the ACC switch (61, 64). As a result, when the vehicle (100) starts moving from an uphill road, the cruise control (ACC) can be started or resumed smoothly without causing the vehicle (100) to roll downhill, thereby improving drivability.

[0016] In the above description, in order to facilitate understanding of the invention, the symbols used in the embodiments are added in parentheses to the constituent elements of the invention corresponding to the embodiments, but each constituent element of the invention is not limited to the embodiments defined by the symbols. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram illustrating the overall configuration of a driving assistance device according to an embodiment of the present invention. [Figure 2] 10 is a timing chart illustrating the flow of ACC restart processing according to the present embodiment. [Figure 3] 10 is a flowchart illustrating a routine for starting processing of ACC according to the present embodiment. [Figure 4] 10 is a flowchart illustrating a routine for restarting the ACC according to the present embodiment. [Figure 5] FIG. 10 is a schematic overall configuration diagram of a driving assistance device according to a modified example. [Figure 6] 10 is a timing chart illustrating the flow of ACC restart processing according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, a driving assistance device, a driving assistance method, and a program according to this embodiment will be described with reference to the drawings. The same components are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[0019] [Overall configuration] 1 is a schematic diagram of the overall configuration of a driving assistance device 1 according to this embodiment. The driving assistance device 1 is mounted on a vehicle 100. The vehicle 100 on which the driving assistance device 1 is mounted is also referred to as "host vehicle" hereinafter in order to distinguish it from other vehicles.

[0020] The driving assistance device 1 has an ECU 10. The ECU 10 has a microcomputer as its main component. ECU is an abbreviation for Electronic Control Unit. The microcomputer includes a CPU, ROM, RAM, an interface, etc., and the CPU realizes various functions by executing instructions (programs, routines) stored in the ROM.

[0021] The ECU 10 is a central control device that provides driving assistance to the driver and performs adaptive cruise control (ACC). Here, driving assistance is a concept that includes autonomous driving. The ACC is a control that causes the host vehicle 100 to travel at a constant speed at a target vehicle speed when there is no preceding vehicle ahead of the host vehicle 100, and causes the host vehicle 100 to follow the preceding vehicle at a speed equal to or lower than the target vehicle speed while maintaining the inter-vehicle distance between the host vehicle 100 and the preceding vehicle at the target inter-vehicle distance when there is a preceding vehicle ahead of the host vehicle 100. The ACC is performed by the ECU 10 controlling the operation of the drive unit 20, the brake unit 30, etc. based on the driving state of the vehicle 100 and the situation around the vehicle 100. For this reason, the ECU 10 is communicably connected to the drive unit 20, the brake unit 30, the vehicle state acquisition device 40, the surroundings recognition device 50, the ACC switch 60, etc.

[0022] The drive unit 20 generates a drive force that is transmitted to the drive wheels of the vehicle 100. Examples of the drive unit 20 include an engine and an electric motor. In this embodiment, the vehicle 100 may be any of a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a fuel cell electric vehicle (FCEV), an electric vehicle (BEV), and an engine vehicle.

[0023] The braking device 30 is, for example, a disc brake device that applies braking force to the wheels of the vehicle 100. Note that the braking device 30 is not limited to a disc brake device and may be a drum brake device or the like. In this embodiment, the vehicle 100 is, for example, a vehicle not equipped with an electric parking brake (EPB), which is not equipped with an electric stop-holding mechanism such as an EPB. Note that the vehicle 100 may also be an EPB-equipped vehicle that is equipped with an EPB.

[0024] The vehicle state acquisition device 40 is a group of sensors that acquire the state of the vehicle 100. Specifically, the vehicle state acquisition device 40 includes a vehicle speed sensor 41, an accelerator sensor 42, a brake sensor 43, a yaw rate sensor 44, a longitudinal acceleration sensor 45, and the like.

[0025] The vehicle speed sensor 41 detects the traveling speed (vehicle speed V) of the vehicle 100 and transmits the detected vehicle speed V to the ECU 10. The vehicle speed sensor 41 may be a wheel speed sensor. The accelerator sensor 42 detects the amount of operation of an accelerator pedal (not shown) by the driver and transmits the detected amount of operation of the accelerator pedal to the ECU 10. The brake sensor 43 detects the amount of operation of a brake pedal (not shown) by the driver and transmits the detected amount of operation of the brake to the ECU 10. The yaw rate sensor 44 detects the yaw rate of the vehicle 100 and transmits the detected yaw rate to the ECU 10. The longitudinal acceleration sensor 45 detects the acceleration G in the longitudinal direction of the vehicle 100 and transmits the detected acceleration G to the ECU 10.

[0026] The surroundings recognition device 50 is a type of sensor that recognizes target information related to targets around the vehicle 100. Specifically, the surroundings recognition device 50 includes a radar sensor 51, a camera sensor 52, etc. Examples of the target information include surrounding vehicles, traffic lights, white lines on the road, signs, fallen objects, etc. The target information around the vehicle 100 acquired by the surroundings recognition device 50 is transmitted to the ECU 10.

[0027] The radar sensor 51 is provided, for example, at the front of the vehicle 100 and detects targets present in the area ahead of the vehicle 100. The radar sensor 51 includes a millimeter-wave radar and / or a lidar. The millimeter-wave radar emits millimeter-wave radio waves (millimeter waves) and receives millimeter waves reflected by targets present within the emission range (reflected waves). The millimeter-wave radar acquires the relative distance Dr between the vehicle 100 and the target, the relative speed Vr between the vehicle 100 and the target, and the like based on the phase difference between the transmitted millimeter waves and the received reflected waves, the attenuation level of the reflected waves, and the time from transmitting the millimeter waves to receiving the reflected waves. The lidar sequentially scans a pulsed laser beam with a wavelength shorter than that of the millimeter waves in multiple directions and receives the reflected light reflected by the target to acquire the shape of the target detected ahead of the vehicle 100, the relative distance Dr between the vehicle 100 and the target, the relative speed Vr between the vehicle 100 and the target, and the like. The relative distance Dr is the distance between the host vehicle 100 and a target (e.g., a preceding vehicle) along the central axis of the host vehicle 100. The relative speed Vr is the difference (=Vb-V) between the speed Vb of the target (e.g., a preceding vehicle) and the vehicle speed V of the host vehicle 100. The target speed Vb is the speed of the target in the traveling direction of the host vehicle 100.

[0028] The camera sensor 52 is, for example, a stereo camera or a monocular camera, and a digital camera having an imaging element such as a CMOS or a CCD can be used. The camera sensor 52 is disposed, for example, above the front windshield glass of the vehicle 100. The camera sensor 52 captures an image of the area ahead of the vehicle 100 and processes the captured image data to acquire target information ahead of the vehicle 100. The target information is information that indicates the type of target detected ahead of the vehicle 100, the relative distance Dr between the vehicle 100 and the target, the relative speed Vr between the vehicle 100 and the target, etc. The type of target may be recognized, for example, by machine learning such as pattern matching.

[0029] The surroundings recognition device 50 repeatedly transmits the acquired target information to the ECU 10 every time a predetermined time has elapsed. The ECU 10 determines the relative relationship between the vehicle 100 and the target by combining the relative relationship between the vehicle 100 and the target obtained by the radar sensor 51 and the relative relationship between the vehicle 100 and the target obtained by the camera sensor 52. Note that the surroundings recognition device 50 does not necessarily have to include both the radar sensor 51 and the camera sensor 52, and may include, for example, only the radar sensor 51 or only the camera sensor 52.

[0030] The ACC switch 60 is provided near the driver's seat (for example, on the steering wheel or steering column) and is a switch operated by the driver. The ACC switch 60 includes a start switch 61, a setting switch 62, a cancel switch 63, a resume switch 64, etc.

[0031] The start switch 61 is a switch that allows the driver to select whether to start or stop the ACC. The setting switch 62 is a switch that allows the driver to arbitrarily set or change the target vehicle speed Vtag and target inter-vehicle distance Dtag (or target inter-vehicle time) of the ACC within a predetermined range. Here, the target vehicle speed Vtag is the vehicle speed that the vehicle 100 maintains when performing constant speed cruise control, which will be described later. The target vehicle speed Vtag has a lower limit speed Vs (e.g., 30 km / h) as the minimum speed that can be set. The target inter-vehicle distance Dtag is the inter-vehicle distance to be maintained between the vehicle and the preceding vehicle at a vehicle speed V equal to or lower than the target vehicle speed Vtag when performing follow-up cruise control, which will be described later.

[0032] The cancel switch 63 is a switch for temporarily canceling ACC that is running. When the driver turns on the cancel switch 63 while ACC is running, ACC is canceled. The resume switch 64 is a switch for restoring ACC that has been temporarily canceled. ACC that has been temporarily canceled by turning on the cancel switch 63 or by depressing the brake pedal can be restored by turning on the resume switch 64 before the driver stops the vehicle 100.

[0033] In this embodiment, the ACC, which is stopped when the vehicle 100 is stopped, can be restarted by the driver turning on the start switch 61 or the resume switch 64. The details of the ACC restart process will be described later.

[0034] [ACC] Next, the ECU 10 according to this embodiment will be described in detail. Focusing on its functions, the ECU 10 has, as some of its functional elements, an ACC control unit 11, a forward start possibility determination unit 12, a start intention determination unit 13, and an ACC start / restart processing unit 14. These functional elements will be described as being included in the ECU 10, which is an integrated piece of hardware, but some of these functional elements may also be provided in an ECU separate from the ECU 10. Furthermore, some of the functional elements of the ECU 10 may also be provided in an external information processing device or the like that is capable of communicating with the vehicle 100.

[0035] The ACC control unit 11 executes ACC based on the target vehicle speed Vtag and the target inter-vehicle distance Dtag. ACC itself is well known (see, for example, Japanese Patent Application Laid-Open No. 2014-148293, Japanese Patent Application Laid-Open No. 2006-315491, Japanese Patent No. 4172434, and Japanese Patent No. 4929777). Therefore, only a brief explanation will be given below. ACC includes two types of control: constant speed cruise control and adaptive cruise control.

[0036] The constant speed traveling control is a control for causing the vehicle 100 to travel at a constant speed in accordance with the target vehicle speed Vtag without requiring the driver to operate the accelerator.

[0037] When there is no preceding vehicle, the ACC control unit 11 executes constant speed cruise control. That is, the ACC control unit 11 determines the target acceleration Gtgt based on the target vehicle speed Vtag and the vehicle speed V so that the vehicle speed V of the vehicle 100 matches the target vehicle speed Vtag. If the current vehicle speed V matches the target vehicle speed Vtag, the ACC control unit 11 sets the target acceleration Gtgt to "0." If the target vehicle speed Vtag is higher than the vehicle speed V, the ACC control unit 11 increases the target acceleration Gtgt. If the target vehicle speed Vtag is lower than the vehicle speed V, the ACC control unit 11 decreases the target acceleration Gtgt.

[0038] The ACC control unit 11 controls the driving of the drive unit 20 so that the acceleration of the vehicle 100 matches the target acceleration Gtgt, in other words, so that the vehicle 100 travels according to the target acceleration Gtgt, and also controls the operation of the braking unit 30 as necessary.

[0039] The following running control is a control for causing the vehicle 100 to run so as to follow the preceding vehicle while maintaining the inter-vehicle distance to the preceding vehicle at the target inter-vehicle distance Dtag.

[0040] When a preceding vehicle is present, the ACC control unit 11 executes follow-up running control. In this case, the ACC control unit 11 selects the vehicle to be followed based on target information acquired by the surroundings recognition device 50. Furthermore, the ACC control unit 11 calculates the target acceleration Gtgt according to either the following formula (1) or formula (2).

[0041] Gtgt(acceleration)=ka1·(k1·ΔD+k2·Vr) …(1) Gtgt (deceleration)=kd1·(k1·ΔD+k2·Vr) …(2) In Equation (1) and Equation (2), Vr is the relative speed of the vehicle to be followed, k1 and k2 are predetermined positive gains (coefficients), and ΔD is the inter-vehicle deviation (=Dr-Dtag) obtained by subtracting the target inter-vehicle distance Dtag from the relative distance Dr of the vehicle to be followed.

[0042] If the value (k1·ΔD+k2·Vr) is positive or "0", the ACC control unit 11 determines the target acceleration Gtgt using equation (1). ka1 is a positive gain (coefficient) for acceleration and is set to a value equal to or less than "1". If the value (k1·ΔD+k2·Vr) is negative, the ACC control unit 11 determines the target acceleration Gtgt using equation (2). kd1 is a gain (coefficient) for deceleration and is set to "1" in this example. The ACC control unit 11 controls the driving of the drive unit 20 so that the acceleration of the vehicle 100 matches the target acceleration Gtgt, in other words, so that the vehicle 100 travels in accordance with the target acceleration Gtgt, and also controls the operation of the braking unit 30 as necessary.

[0043] The ACC control unit 11 temporarily cancels the ACC when any of the following cancellation conditions is met. Cancellation condition (1): When the driver turns on the cancel switch 63 while ACC is running. Release condition (2): When the driver presses the brake pedal while ACC is running. When the ACC is released, the driving mode transitions from a driving assistance mode in which constant speed driving control or follow-up driving control is performed to a normal driving mode in which driving operation of the vehicle 100 is left to the driver.

[0044] When the cancellation condition (1) or (2) is satisfied, the ACC control unit 11 temporarily cancels the ACC and temporarily stores the target vehicle speed Vtag and target inter-vehicle distance Dtag of the canceled ACC in the RAM of the ECU 10. After canceling the ACC due to the satisfaction of the cancellation condition (1) or (2), the ACC control unit 11 resumes the ACC if the driver turns on the resume switch 64 before the vehicle 100 stops. In this case, the ACC is executed based on the target vehicle speed Vtag and target inter-vehicle distance Dtag temporarily stored in the RAM.

[0045] The ACC control unit 11 stops, that is, disables, the ACC when any of the following stop conditions is met. Stop condition (1): When the driver turns off the start switch 61. Stop condition (2): When the host vehicle 100 stops due to the stop of the preceding vehicle while follow-up cruise control is being executed. Stop condition (3): After the ACC is released due to the satisfaction of the release condition (1) or (2), the vehicle 100 is stopped without the driver turning on the resume switch 64.

[0046] When the ACC control unit 11 stops the ACC because stop condition (1) is satisfied, it resets (deletes) the target vehicle speed Vtag and the target inter-vehicle distance Dtag. Furthermore, when the ACC control unit 11 stops the ACC because stop condition (2) is satisfied, it switches the start switch 61 from ON to OFF and temporarily stores the target vehicle speed Vtag and target inter-vehicle distance Dtag of the stopped ACC in the RAM of the ECU 10. Furthermore, when the ACC control unit 11 stops the ACC because stop condition (3) is satisfied, it switches the start switch 61 from ON to OFF and retains the target vehicle speed Vtag and target inter-vehicle distance Dtag that were temporarily stored in the RAM of the ECU 10 when the ACC was released. After the ACC is stopped, the stopping operation to continuously stop the vehicle 100 is left to the driver's braking operation.

[0047] The forward start possibility determination unit 12 determines whether or not the vehicle 100 is in a state where it can start moving forward while the driver is depressing the brake pedal to stop the vehicle 100. Hereinafter, the state where the stopped vehicle 100 can start moving forward is referred to as a "forward start possible state."

[0048] The forward departure possibility determination unit 12 determines whether or not a preceding vehicle exists in front of the stopped host vehicle 100 based on the detection result of the surroundings recognition device 50. If a preceding vehicle exists, the forward departure possibility determination unit 12 determines whether or not the preceding vehicle has started forward. If the preceding vehicle has started forward, the forward departure possibility determination unit 12 determines whether or not the following departure possibility conditions are met. Start enabling condition (1): The relative distance Dr of the preceding vehicle to the host vehicle 100 increases to a predetermined threshold distance Dth (Dr≧Dth). Start enabling condition (2): The relative speed Vr of the preceding vehicle with respect to the host vehicle 100 increases to a predetermined threshold speed Vth (Vr≧Vth).

[0049] The forward departure possibility determination unit 12 determines that the host vehicle 100 is in a forward departure possible state when either the departure possible condition (1) or (2) is met. On the other hand, when neither the departure possible condition (1) nor (2) is met, the forward departure possibility determination unit 12 determines that the host vehicle 100 is not in a forward departure possible state. Hysteresis may be added to the threshold distance Dth and the threshold speed Vth to prevent the determination result from repeatedly switching within a short period of time.

[0050] On the other hand, there may be cases where there is no preceding vehicle ahead of the stopped host vehicle 100, such as when the host vehicle 100 is stopped at the front of an intersection with a red light. In such cases, the forward departure possibility determination unit 12 recognizes the light color of the traffic light based on the detection result of the surroundings recognition device 50, and determines that the host vehicle 100 is in a state where it is possible to start forward when the light color of the traffic light changes from red to green. The light color of the traffic light may be recognized by performing machine learning such as pattern matching based on image data of the traffic light captured by the camera sensor 52. Note that when there is no preceding vehicle, the forward departure possibility determination unit 12 may not determine whether it is possible to start forward, but may leave it to the driver's visual judgment.

[0051] When it is determined that the host vehicle 100 can start forward, the start intention determination unit 13 determines whether or not the driver intends to start the vehicle 100 using ACC. Hereinafter, the driver's intention to start the vehicle 100 using ACC will be simply referred to as "ACC start intention."

[0052] The start intention determination unit 13 first determines whether the driver has performed a first start operation of releasing the brake pedal. The release of the brake pedal may be determined based on the detection result of the brake sensor 43. If the driver has performed the first start operation, the start intention determination unit 13 determines whether the driver has performed either a second start operation of turning on the start switch 61 or a third start operation of turning on the resume switch 64. If the driver performs either the second start operation or the third start operation after performing the first start operation, the start intention determination unit 13 determines that the driver has an intention to start in ACC mode. On the other hand, if the driver has performed the first start operation but has not performed either the second start operation or the third start operation, the start intention determination unit 13 determines that the driver has no intention to start in ACC mode.

[0053] When the host vehicle 100 is stopped and it is determined that the host vehicle 100 is able to start moving forward and that the driver has the intention to start with ACC, the ACC start / restart processing unit 14 sends an instruction signal to the ACC control unit 11 to start or restart ACC.

[0054] Here, starting ACC refers to the case where the driver executes ACC by first turning on the start switch 61 after turning on the ignition switch or power switch of the vehicle 100, or the case where the driver executes ACC by turning on the start switch 61 again after turning off the start switch 61 (stop condition (1) described above) and before turning off the ignition switch or power switch. Also, resuming ACC refers to the case where the driver executes ACC again by turning on the start switch 61 or resume switch 64 before turning off the ignition switch or power switch of the vehicle 100 after the system stops ACC due to the vehicle 100 being stopped with the start switch 61 on.

[0055] The ACC control unit 11 starts or resumes ACC when it receives an instruction signal from the ACC start / restart processing unit 14. When the driver performs a second start operation by turning on the start switch 61, the ACC control unit 11 sets the target vehicle speed Vtag to the lower limit vehicle speed Vs and starts or resumes ACC. On the other hand, when the driver performs a third start operation by turning on the resume switch 64, the ACC control unit 11 resumes ACC based on the target vehicle speed Vtag that was temporarily stored in the RAM of the ECU 10 when ACC was released. Note that turning on the resume switch 64 is valid when resuming ACC, but is invalid when starting ACC.

[0056] In this embodiment, when the driver starts the stopped vehicle 100 using the ACC, the ACC can be started or resumed early with only two steps: (1) releasing the brake pedal and (2) turning on the start switch 61 or the resume switch 64 while the vehicle 100 is ready to start moving forward. In other words, the accelerator operation required to start or resume ACC in a conventional vehicle without an EPB, specifically, the accelerator operation required to increase the vehicle speed V to the lower limit vehicle speed Vs, is no longer necessary. This effectively prevents the driver from feeling annoyed and reliably improves operational convenience. Furthermore, the ACC can be started or resumed early, before the vehicle speed V reaches the lower limit vehicle speed Vs, thereby improving drivability.

[0057] Next, the flow of the ACC restart process according to this embodiment will be described based on the timing chart shown in Fig. 2. Note that the only difference between the cases where a preceding vehicle 200 is present ahead of the stopped host vehicle 100 and where it is not is the process of determining whether the vehicle is ready to start ahead; other processes are the same, so the following will describe the case where a preceding vehicle 200 is present. Also, the only difference between the ACC start process and the ACC restart process is whether the resume switch 64 is ON or not, so the following will describe the ACC restart process.

[0058] At time t0, the ACC is stopped due to the satisfaction of the above-mentioned stop condition (2) or (3), and the driver has depressed the brake pedal to stop the vehicle 100. At time t1, when the preceding vehicle 200 starts moving, the ECU 10 starts the process of determining whether forward starting is possible. At time t2, when either the start possible condition (1) in which the relative distance Dr of the preceding vehicle 200 to the host vehicle 100 is equal to or greater than a predetermined threshold distance Dth, or the start possible condition (2) in which the relative speed Vr of the preceding vehicle 200 to the host vehicle 100 is equal to or greater than a predetermined threshold speed Vth, is satisfied, the ECU 10 determines that the host vehicle 100 is in a forward start possible state.

[0059] At time t3, the driver releases the brake pedal, and at time t4, the driver turns on the start switch 61 (or the resume switch 64), and the ECU 10 resumes the ACC from time t4. That is, from time t4, the following travel control of the ACC, which causes the host vehicle 100 to follow the preceding vehicle 200, is resumed without the driver needing to operate the accelerator.

[0060] In contrast, with conventional control, ACC cannot be resumed unless the driver determines that forward start is possible, releases the brake pedal, and depresses the accelerator pedal to increase the vehicle speed V to the lower limit vehicle speed Vs, and then turns on the start switch. In this embodiment, ACC can be resumed early without waiting for such accelerator operation or an increase in vehicle speed V, so compared to conventional control, it is possible to effectively reduce the inconvenience to the driver and reliably improve operational convenience.

[0061] Next, a routine for processing to start the ACC by the ECU 10 will be described based on the flowchart shown in Fig. 3. The routine shown in Fig. 3 is started when the ACC is stopped by default (the start switch 61 is OFF) after the ignition switch or power switch of the vehicle 100 is turned ON, or when the driver turns the start switch 61 OFF (the above-mentioned stop condition (1) is satisfied).

[0062] In step S100, the ECU 10 determines whether the vehicle 100 is stopped. Whether the vehicle 100 is stopped may be determined based on the detection result of the vehicle speed sensor 41. If the vehicle 100 is stopped (Yes), the ECU 10 proceeds to processing of step S110. On the other hand, if the vehicle 100 is not stopped (No), that is, if the vehicle 100 is running, the ECU 10 proceeds to processing of step S180.

[0063] In step S180, the ECU 10 detects whether the start switch 61 is turned on. If the start switch 61 is turned on, the ECU 10 proceeds to the processing of step S185. On the other hand, if the start switch 61 is not turned on (No), that is, if the start switch 61 is off, the ECU 10 temporarily ends (returns) this routine.

[0064] In step S185, the ECU 10 determines whether the current vehicle speed V of the vehicle 100 exceeds the lower limit vehicle speed Vs, based on the detection result of the vehicle speed sensor 41. If the vehicle speed V exceeds the lower limit vehicle speed Vs (Yes), the ECU 10 proceeds to the process of step S190, sets the current vehicle speed V to the target vehicle speed Vtag, and starts ACC. On the other hand, if the vehicle speed V does not exceed the lower limit vehicle speed Vs (No), the ECU 10 proceeds to the process of step S195, sets the lower limit vehicle speed Vs to the target vehicle speed Vtag, and starts ACC. After starting ACC in step S190 or S195, the ECU 10 temporarily ends (returns) this routine.

[0065] If the determination in step S100 is affirmative (Yes), that is, if the vehicle 100 is stopped, the ECU 10 proceeds to processing in step S110, and determines whether or not a preceding vehicle that is stopped is present ahead of the host vehicle 100, based on the detection result of the surroundings recognition device 50. If a preceding vehicle is present (Yes), the ECU 10 proceeds to processing in step S115. On the other hand, if a preceding vehicle is not present (No), the ECU 10 proceeds to processing in step S130.

[0066] In step S115, the ECU 10 determines whether the preceding vehicle has started moving forward. If the preceding vehicle has started moving forward (Yes), the ECU 10 proceeds to the process of step S120. On the other hand, if the preceding vehicle has not started moving (No), that is, if the preceding vehicle is stopped, the ECU 10 repeats the determination of step S115.

[0067] In step S120, the ECU 10 determines whether or not either a start enabling condition (1) in which the relative distance Dr of the preceding vehicle to the host vehicle 100 is equal to or greater than a predetermined threshold distance Dth, or a start enabling condition (2) in which the relative speed Vr of the preceding vehicle to the host vehicle 100 is equal to or greater than a predetermined threshold speed Vth, is met. If either the start enabling condition (1) or (2) is met, the ECU 10 proceeds to processing of step S140. On the other hand, if neither the start enabling condition (1) nor the start enabling condition (2) is met (No), the ECU 10 repeats the determination of step S120.

[0068] If the determination in step S110 is negative (No), that is, if there is no preceding vehicle stopped ahead of the host vehicle 100, it is assumed that the host vehicle 100 is stopped at the front of an intersection with a red light. In this case, the ECU 10 proceeds to the process of step S130, and determines whether or not there is a traffic light ahead of the host vehicle 100 based on the detection result of the camera sensor 52. If there is a traffic light (Yes), the ECU 10 proceeds to the process of step S135. On the other hand, if there is no traffic light, the ECU 10 proceeds to the process of step S140.

[0069] In step S135, ECU 10 determines whether the traffic light is green based on image data captured by camera sensor 52. If the traffic light is green (Yes), ECU 10 proceeds to the process of step S140. On the other hand, if the traffic light is not green (No), that is, if the traffic light is red, ECU 10 repeats the determination of step S135. Note that if the traffic light color is left to the driver's visual judgment, the processes of steps S130 and S135 can be omitted and the process can proceed to the process of step S140.

[0070] In step S140, the ECU 10 determines that the host vehicle 100 is in a state in which it can start forward. Next, in step S145, the ECU 10 determines whether or not the driver has performed a first start operation of releasing the brake pedal. If the driver has performed the first start operation (Yes), the ECU 10 proceeds to the processing of step S150. On the other hand, if the driver has not performed the first start operation (No), that is, if the vehicle 100 remains stopped, the ECU 10 proceeds to the processing of step S170.

[0071] In step S150, the ECU 10 determines whether or not the driver has performed the second start operation of turning on the activation switch 61. If the driver has performed the second start operation (Yes), the ECU 10 proceeds to the process of step S160. On the other hand, if the driver has not performed the second start operation (No), the ECU 10 proceeds to the process of step S170.

[0072] In step S170, the ECU 10 determines whether the elapsed time since the host vehicle 100 became capable of starting forward has reached a predetermined threshold time. If the elapsed time has not reached the predetermined threshold time (No), the ECU 10 returns to the processing of step S145. On the other hand, if the elapsed time has reached the predetermined threshold time (Yes), the ECU 10 proceeds to the processing of step S175, determines that the driver has no intention of starting the vehicle in ACC mode, and temporarily ends (returns) this routine without starting ACC.

[0073] If the determination in step S150 is affirmative (Yes), that is, if the driver has performed the second starting operation, the ECU 10 proceeds to step S160 and determines that the driver intends to start in ACC mode. Next, in step S165, the ECU 10 sets the lower limit vehicle speed Vs to the target speed Vtag and starts ACC. Once ACC has started, the ECU 10 temporarily ends (returns) this routine.

[0074] Next, a routine for restarting the ACC by the ECU 10 will be described with reference to the flowchart shown in Fig. 4. This routine starts when the ACC is executed according to the flow shown in Fig. 3.

[0075] In step S200, the ECU 10 determines whether the stop condition (2) is satisfied, i.e., whether the host vehicle 100 has stopped as the preceding vehicle has stopped while follow-up cruise control is being performed. If the stop condition (2) is satisfied (Yes), the ECU 10 proceeds to the process of step S205, where the start switch 61 is switched from ON to OFF to stop, i.e., disable, the ACC. After the ACC is stopped in step S205, the ECU 10 proceeds to the process of step S230.

[0076] If the determination in step S200 is negative (No), that is, if the stop condition (2) is not satisfied, ECU 10 proceeds to the process of step S210.

[0077] In step S210, the ECU 10 determines whether the stop condition (3) is met, i.e., whether the vehicle 100 has stopped without restoring the ACC after it was temporarily released. If the stop condition (3) is met (Yes), the ECU 10 proceeds to the process of step S215, where the start switch 61 is switched from ON to OFF to stop, i.e., disable, the ACC. After the ACC is stopped in step S215, the ECU 10 proceeds to the process of step S220. On the other hand, if the stop condition (3) is not met (No) in the determination of step S210, the ECU 10 temporarily ends (returns) this routine.

[0078] If the determination in step S210 is affirmative (Yes), that is, if the stop condition (3) is satisfied, it is assumed that there may or may not be a preceding vehicle that is stopped ahead of the host vehicle 100. Therefore, in step S220, the ECU 10 determines whether or not there is a preceding vehicle that is stopped ahead of the host vehicle 100 based on the detection result of the surroundings recognition device 50. If there is a preceding vehicle (Yes), the ECU 10 proceeds to processing in step S230. On the other hand, if there is no preceding vehicle (No), the ECU 10 proceeds to processing in step S224.

[0079] In step S230, the ECU 10 determines whether the preceding vehicle has started moving forward. If the preceding vehicle has started moving forward (Yes), the ECU 10 proceeds to the process of step S235. On the other hand, if the preceding vehicle has not started moving (No), that is, if the preceding vehicle is stopped, the ECU 10 repeats the determination of step S230.

[0080] In step S235, the ECU 10 determines whether either a start enabling condition (1) in which the relative distance Dr of the preceding vehicle to the host vehicle 100 is equal to or greater than a predetermined threshold distance Dth, or a start enabling condition (2) in which the relative speed Vr of the preceding vehicle to the host vehicle 100 is equal to or greater than a predetermined threshold speed Vth, is met. If either the start enabling condition (1) or (2) is met, the ECU 10 proceeds to processing in step S240. On the other hand, if neither the start enabling condition (1) nor the start enabling condition (2) is met (No), the ECU 10 repeats the determination in step S235.

[0081] If the determination in step S220 is negative (No), that is, if there is no preceding vehicle stopped ahead of the host vehicle 100, it is assumed that the host vehicle 100 is stopped at the front of an intersection with a red light. In this case, the ECU 10 proceeds to the process of step S224, and determines whether or not there is a traffic light ahead of the host vehicle 100 based on the detection result of the camera sensor 52. If there is a traffic light (Yes), the ECU 10 proceeds to the process of step S228. On the other hand, if there is no traffic light, the ECU 10 proceeds to the process of step S240.

[0082] In step S228, ECU 10 determines whether the traffic light is green based on image data captured by camera sensor 52. If the traffic light is green (Yes), ECU 10 proceeds to step S240. On the other hand, if the traffic light is not green (No), that is, if the traffic light is red, ECU 10 repeats the determination of step S228. Note that if the traffic light color is left to the driver's visual judgment, steps S224 and S228 may be omitted and the process may proceed to step S240.

[0083] In step S240, the ECU 10 determines that the host vehicle 100 is in a state in which it can start forward. Next, in step S245, the ECU 10 determines whether or not the driver has performed a first start operation of releasing the brake pedal. If the driver has performed the first start operation (Yes), the ECU 10 proceeds to the processing of step S250. On the other hand, if the driver has not performed the first start operation (No), that is, if the vehicle 100 remains stopped, the ECU 10 proceeds to the processing of step S270.

[0084] In step S250, the ECU 10 determines whether the driver has performed a second start operation of turning on the start switch 61 or a third start operation of turning on the resume switch 64. If the driver has performed either the second start operation or the third start operation (Yes), the ECU 10 proceeds to the processing of step S260. On the other hand, if the driver has not performed either the second start operation or the third start operation (No), the ECU 10 proceeds to the processing of step S270.

[0085] In step S270, the ECU 10 determines whether the elapsed time since the host vehicle 100 became capable of starting forward has reached a predetermined threshold time. If the elapsed time has not reached the predetermined threshold time (No), the ECU 10 returns to the processing of step S245. On the other hand, if the elapsed time has reached the predetermined threshold time (Yes), the ECU 10 proceeds to the processing of step S275, determines that the driver has no intention of starting in ACC, and temporarily ends (returns) this routine without resuming ACC.

[0086] If the determination in step S250 is affirmative (Yes), i.e., if the driver has performed the second or third start operation, the ECU 10 proceeds to step S260 and determines that the driver intends to start the vehicle in ACC mode. Next, in step S265, the ECU 10 resumes ACC. If the driver has performed the second start operation, i.e., turned on the start switch 61, the ECU 10 sets the lower limit vehicle speed Vs as the target speed Vtag and resumes ACC. On the other hand, if the driver has performed the third start operation, i.e., turned on the resume switch 64, the ECU 10 resumes ACC based on the target vehicle speed Vtag that was temporarily stored in the RAM of the ECU 10 when the ACC was released. Once ACC has been resumed, the ECU 10 temporarily ends (returns) this routine.

[0087] According to the present embodiment described above in detail, when the driver starts the stopped vehicle 100 using ACC, the ACC can be started quickly by simply (1) releasing the brake pedal and (2) turning on the start switch 61 while the vehicle 100 is ready to start moving forward. Furthermore, the ACC can be resumed quickly by simply (1) releasing the brake pedal and (2) turning on the start switch 61 or the resume switch 64 while the vehicle 100 is ready to start moving forward. In other words, the accelerator operation required to start or resume ACC in a conventional vehicle not equipped with an EPB, specifically, the operation of depressing the accelerator pedal to increase the vehicle speed V to the lower limit vehicle speed Vs, is no longer necessary. This effectively prevents the driver from feeling annoyed and reliably improves the convenience of operation.

[0088] The above describes the driving assistance device, driving assistance method, and program according to this embodiment, but the present disclosure is not limited to the above embodiment, and various modifications are possible as long as they do not deviate from the purpose of the present invention.

[0089] [Variations] 5 is a schematic diagram of the overall configuration of a driving assistance device 1 according to a modified example. In this modified example, the ECU 10 includes a hill-hold control unit 15 as a functional element. When the host vehicle 100 comes to a stop on an uphill road, the hill-hold control unit 15 applies braking force to the wheels of the host vehicle 100 to hold the vehicle 100 in place regardless of the driver's brake operation, thereby performing so-called hill-hold control to prevent the host vehicle 100 from rolling downhill.

[0090] When the vehicle 100 comes to a stop, the hill-hold control unit 15 estimates the gradient θ of the uphill road based on the longitudinal acceleration G detected by the longitudinal acceleration sensor 45. If the vehicle 100 is equipped with a gradient sensor, the gradient θ may be detected directly by the gradient sensor. If the gradient θ is equal to or greater than a predetermined threshold gradient θth, the hill-hold control unit 15 activates the braking device 30 to initiate hill-hold control, which applies braking force to the wheels of the vehicle 100. Here, the braking force may be a fixed value or may be a variable value that varies depending on the gradient θ.

[0091] After starting hill hold control, the hill hold control unit 15 releases the braking force when the driver depresses the accelerator pedal. Also, after starting hill hold control, the hill hold control unit 15 releases the braking force when the driver turns on the start switch 61 to start ACC, or when the driver turns on the start switch 61 or the resume switch 64 to resume ACC.

[0092] Next, the flow of the ACC restart process according to the modified example will be described based on the timing chart shown in Fig. 6. Note that the only difference between the cases where a preceding vehicle 200 is present ahead of the stopped host vehicle 100 and where it is not is the process of determining whether forward departure is possible; other processes are the same, so the following will describe the case where a preceding vehicle 200 is present. Also, the only difference between the ACC start process and the ACC restart process is whether the resume switch 64 is ON or not, so the following will describe the ACC restart process.

[0093] At time t0, the ACC is stopped due to the satisfaction of the stop condition (2) or (3) described above, and hill-hold control is being executed due to the host vehicle 100 being stopped on an uphill road. At time t1, when the preceding vehicle 200 starts moving, the ECU 10 starts the process of determining whether forward starting is possible. At time t2, when either the start possible condition (1) in which the relative distance Dr of the preceding vehicle 200 to the host vehicle 100 is equal to or greater than a predetermined threshold distance Dth, or the start possible condition (2) in which the relative speed Vr of the preceding vehicle 200 to the host vehicle 100 is equal to or greater than a predetermined threshold speed Vth, is satisfied, the ECU 10 determines that the host vehicle 100 is in a state in which forward starting is possible.

[0094] At time t3, the driver releases the brake pedal, and at time t4, the driver turns on the start switch 61 (or resume switch 64), and the ECU 10 releases the braking force provided by the hill-hold control and resumes ACC. That is, even if the driver releases the brake pedal at time t3, the braking force provided by the hill-hold control is applied until the driver turns on the start switch 61 (or resume switch 64) at time t4. As a result, even if the driver releases the brake pedal when the vehicle 100 starts from a stopped state on an uphill road, the vehicle 100 does not roll downhill, and ACC can be smoothly resumed, thereby improving drivability.

[0095] [others] In the above embodiment, the ECU 10 may further have a function of performing automatic stop control to activate the braking device 30 and stop the host vehicle 100 in front of the traffic light when a red traffic light is detected ahead of the traveling vehicle 100. In this case, the following stop condition may be added as a stop condition for the ACC in addition to the above-described stop conditions (1) to (3). Stop condition (4): When the host vehicle 100 is stopped in front of a traffic light due to automatic stop control while ACC is running.

[0096] Even when the vehicle 100 stops due to the satisfaction of the stop condition (4), as in the above embodiment, when the vehicle 100 is in a state where it can start moving forward, the driver releases the brake pedal and turns on the start switch 61 (or the resume switch 64), thereby starting or resuming the ACC, thereby effectively improving convenience. [Explanation of symbols]

[0097] 1... driving assistance device, 10... ECU, 11... ACC control unit, 12... forward start possibility determination unit, 13... starting intention determination unit, 14... ACC start / restart processing unit, 15... hill hold control unit, 16... deceleration control unit, 30... braking device, 40... vehicle state acquisition device, 41... vehicle speed sensor, 42... accelerator sensor, 43... brake sensor, 44... yaw rate sensor, 45... longitudinal acceleration sensor, 50... surrounding recognition device, 51... radar sensor, 52... camera sensor, 60... ACC switch, 61... start switch, 62... setting switch, 63... cancel switch, 64... resume switch, 100... host vehicle, 200... preceding vehicle

Claims

1. A driving assistance device for a vehicle, a control unit that executes at least one of constant speed travel control for causing the host vehicle to travel at a constant speed and follow-up travel control for causing the host vehicle to follow a preceding vehicle based on a situation around the host vehicle, and that disables the travel control when the host vehicle stops with the travel control enabled and thereafter a brake pedal operation by an occupant of the host vehicle causes the host vehicle to stop; a detection unit that detects the release of a brake pedal by an occupant of the vehicle; a reception unit capable of receiving an assistance request from the occupant, the control unit, when the detection unit detects the release of the brake pedal while the host vehicle is stopped with the driving control disabled and the reception unit receives the assistance request, enables the driving control to start or resume the driving control; When the host vehicle is stopped on an uphill road due to depression of the brake pedal by the occupant, a braking force maintaining control is executed to maintain a braking force for maintaining the host vehicle in a stopped state; the braking force maintenance control is a control for releasing the braking force when the occupant depresses the accelerator pedal after releasing the brake pedal, When the braking force maintaining control is being executed with the driving control disabled, the braking force is maintained even if the detection unit detects the release of the brake pedal, and when the reception unit receives the assistance request, the braking force is released and the driving control is enabled. A driving assistance device characterized by:

2. The driving assistance device according to claim 1, a determination unit that determines whether the host vehicle has reached a start-ready state in which the host vehicle can start moving forward based on a situation around the host vehicle while the host vehicle is stopped, The control unit enables the driving control when the determination unit determines that the host vehicle is in the start-possible state while the host vehicle is stopped with the driving control disabled, the detection unit detects that the brake pedal is released, and the reception unit receives the assistance request. Driving assistance device.

3. The driving assistance device according to claim 2, When the host vehicle stops at an intersection equipped with a traffic light, the determination unit determines whether the host vehicle is in a start-ready state in which it can start moving forward by recognizing a change in the light color of the traffic light based on a detection result of a surroundings recognition device that recognizes the surroundings of the host vehicle. Driving assistance device.

4. The driving assistance device according to claim 2 or 3, When the determination unit determines that the host vehicle is in the start-ready state while the host vehicle is stopped with the travel control disabled, the control unit enables the travel control if the detection unit detects that the brake pedal is released and the reception unit receives the assistance request before the elapsed time from when the host vehicle was determined to be in the start-ready state reaches a predetermined threshold time. Driving assistance device.

5. The driving assistance device according to any one of claims 1 to 4, The vehicle is a vehicle not equipped with an electric parking brake. Driving assistance device.

6. A vehicle driving assistance method, comprising: Based on the situation around the host vehicle, at least one of constant speed travel control for causing the host vehicle to travel at a constant speed and follow-up travel control for causing the host vehicle to travel following a preceding vehicle is executed, and the host vehicle stops with the travel control enabled, and thereafter, when the host vehicle is stopped by a brake pedal operation by an occupant of the host vehicle, the travel control is disabled to stop the travel control; When detecting a brake pedal release by an occupant of the host vehicle while the host vehicle is stopped with the travel control disabled and receiving an assistance request from the occupant, enabling the travel control to start or resume the travel control; When the host vehicle is stopped on an uphill road due to depression of the brake pedal by the occupant, a braking force maintaining control is executed to maintain a braking force for maintaining the host vehicle in a stopped state; the braking force maintenance control is a control for releasing the braking force when the occupant depresses the accelerator pedal after releasing the brake pedal, When the braking force maintaining control is being executed with the travel control disabled, the braking force is maintained even if the release of the brake pedal is detected, and when the assistance request is received, the braking force is released and the travel control is enabled. A driving assistance method comprising:

7. The computer of the vehicle's driving assistance device Based on the situation around the host vehicle, at least one of constant speed travel control and follow-up travel control for causing the host vehicle to follow a preceding vehicle is executed, and the host vehicle stops with the travel control enabled, and thereafter, when the host vehicle is stopped by a brake pedal operation by an occupant of the host vehicle, the travel control is disabled to stop the travel control; When detecting a brake pedal release by an occupant of the host vehicle while the host vehicle is stopped with the travel control disabled and receiving an assistance request from the occupant, enabling the travel control to start or resume the travel control; When the host vehicle is stopped on an uphill road due to depression of the brake pedal by the occupant, a braking force maintaining control is executed to maintain a braking force for maintaining the host vehicle in a stopped state; the braking force maintenance control is a control for releasing the braking force when the occupant depresses the accelerator pedal after releasing the brake pedal, When the braking force maintaining control is being executed with the travel control disabled, the braking force is maintained even if the release of the brake pedal is detected, and when the assistance request is received, the braking force is released and a process of enabling the travel control is executed. A program characterized by:

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