Speed control device, speed control method, and program

Abstract

To suppress unnecessary deceleration.SOLUTION: A speed control device 30 includes: an acquisition unit 321 that acquires a vertical distance being an inter-vehicle distance between a position of another vehicle traveling ahead in a traveling direction of an own vehicle and a position of the own vehicle in the longitudinal direction of the own vehicle from a first measuring device that identifies the position of the other vehicle on the basis of reflected waves of light waves or radio waves emitted toward the other vehicle; a determination unit 322 that determines a first deceleration time during which deceleration is performed at second deceleration smaller than first deceleration that brings relative speed of the own vehicle relative to the other vehicle to zero on the basis of the relative speed between the other vehicle and the own vehicle and the vertical distance at a first time point; and a speed control unit 323 that decelerates the own vehicle at the second deceleration from the first time point to a second time point of when the first deceleration time has elapsed, and decelerates the own vehicle at a third deceleration greater than the first deceleration after the second time point.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] When a second other vehicle different from the first other vehicle cuts in between the host vehicle and the first other vehicle traveling ahead in the traveling direction of the host vehicle, the vehicle control device of Patent Document 1 determines the upper limit value of the deceleration of the host vehicle based on the difference between the speed of the host vehicle and the speed of the second other vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When traveling in the vicinity of an object that reflects radio waves (for example, the inner wall of a tunnel, the outer wall of a building), the conventional vehicle control device may obtain an incorrect position of another vehicle from the radar provided in the host vehicle by acquiring radio waves reflected by the radar from multiple propagation paths. As a result, there has been a problem that another vehicle traveling in a lane adjacent to the lane in which the host vehicle is traveling is misrecognized as another vehicle traveling ahead in the traveling direction of the host vehicle, resulting in unnecessary deceleration.

[0005] Therefore, the present invention has been made in view of these points, and an object thereof is to suppress unnecessary deceleration.

Means for Solving the Problems

[0006] The speed control device according to the first aspect of the present invention includes an acquisition unit that acquires a longitudinal distance, which is a distance between the position of another vehicle traveling ahead of the own vehicle in the longitudinal direction of the own vehicle and the position of the own vehicle, from a first measurement device that identifies the position of the other vehicle based on a reflected wave of light waves or radio waves emitted to the other vehicle; a determination unit that determines a first deceleration time for decelerating the own vehicle at a second deceleration smaller than a first deceleration that makes the relative speed of the own vehicle with respect to the other vehicle zero, based on the relative speed between the other vehicle and the own vehicle and the longitudinal distance at a first time; and a speed control unit that decelerates the own vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerates the own vehicle at a third deceleration greater than the first deceleration at a time after the second time.

[0007] The acquisition unit acquires the vehicle speed of the own vehicle, and when the vehicle speed is equal to or higher than a first threshold value, the speed control unit decelerates the own vehicle at the second deceleration from the first time to the first deceleration time, and when the vehicle speed is lower than the first threshold value, the speed control unit may decelerate the own vehicle at the third deceleration at a time after the first time.

[0008] The acquisition unit acquires a first lateral distance between the position of the other vehicle and the position of the own vehicle in the width direction of the own vehicle measured by the first measurement device, and a second lateral distance different from the first lateral distance measured by a second measurement device that identifies the position of the other vehicle based on an imaging image generated by imaging the front of the own vehicle in the traveling direction. When the speed control unit detects that the difference between the first lateral distance and the second lateral distance is equal to or greater than a second threshold value, the speed control unit may decelerate the own vehicle at the second deceleration from the detected time to the first deceleration time.

[0009] The acquisition unit acquires vehicle identification information for identifying the other vehicle from the first measurement device in association with the longitudinal distance or the first lateral distance. When the vehicle identification information acquired at a time before a predetermined time is different from the vehicle identification information acquired at the predetermined time, the speed control unit may decelerate the own vehicle at the second deceleration from the predetermined time to the first deceleration time.

[0010] Based on the relative speed and the longitudinal distance at the first time, the determination unit determines a first target deceleration which is the upper limit value of the second deceleration, a second target deceleration which is the upper limit value of the third deceleration, and a second deceleration time for decelerating at the third deceleration. The speed control unit may decelerate the host vehicle so that the second deceleration reaches the first target deceleration at the first deceleration time, and may decelerate the host vehicle so that the third deceleration reaches the second target deceleration at the second deceleration time.

[0011] The apparatus further includes a storage unit that stores a first change amount map indicating a change amount of the second deceleration per unit time corresponding to the relative speed and the longitudinal distance, and a second change amount map indicating a change amount of the third deceleration per unit time corresponding to the relative speed and the longitudinal distance. The speed control unit may decelerate the host vehicle at the second deceleration determined by referring to the first change amount map at the first deceleration time, and may decelerate the host vehicle at the third deceleration determined by referring to the second change amount map at the second deceleration time.

[0012] The determination unit determines a standby time from the first time until a time when deceleration at the second deceleration starts, based on the relative speed and the longitudinal distance at the first time. The speed control unit may decelerate the host vehicle at the second deceleration from the time when the standby time has elapsed until the first deceleration time.

[0013] The acquisition unit acquires the vehicle speed of the host vehicle. When the vehicle speed is equal to or higher than a third threshold value, the speed control unit may decelerate the host vehicle at the second deceleration from the time when the standby time has elapsed until the first deceleration time.

[0014] When the relative speed at the first time indicates that the speed of the host vehicle is greater than the speed of the other vehicle, the speed control unit may decelerate the host vehicle at the second deceleration from the time when the standby time has elapsed.

[0015] The acquisition unit acquires vehicle identification information for identifying the other vehicle from the first measuring device, in association with the longitudinal distance or a first lateral distance between the position of the other vehicle and the position of the host vehicle in the width direction of the host vehicle. When the vehicle identification information acquired at a predetermined time and the vehicle identification information acquired at a time earlier than the predetermined time are different during the standby time, the speed control unit may start decelerating the host vehicle at the second deceleration at the time when the standby time has elapsed from the predetermined time.

[0016] The acquisition unit acquires vehicle identification information for identifying the other vehicle from the first measuring device, in association with the longitudinal distance or a first lateral distance between the position of the other vehicle and the position of the host vehicle in the width direction of the host vehicle. When the first vehicle identification information at a predetermined time is different from the second vehicle identification information at a time earlier than the predetermined time during the standby time or the first deceleration time, the speed control unit may decelerate the host vehicle at a deceleration based on the relative speed and the longitudinal distance associated with the first vehicle identification information.

[0017] The acquisition unit acquires a first lateral distance between the position of the other vehicle and the position of the host vehicle in the width direction of the host vehicle measured by the first measuring device, and a second lateral distance different from the first lateral distance measured by a second measuring device that specifies the position of the other vehicle based on a captured image generated by imaging the front in the traveling direction of the host vehicle. After the standby time has elapsed, when the difference between the first lateral distance and the second lateral distance is greater than or equal to a second threshold value, the speed control unit may not decelerate the host vehicle.

[0018] The acquisition unit acquires other vehicle information indicating the presence or absence of other vehicles traveling in an area measurable by the first measuring device in front of the traveling direction of the host vehicle. When the acquisition unit acquires the other vehicle information indicating that no other vehicle is present while the host vehicle is being decelerated, the speed control unit may accelerate the host vehicle after ending the deceleration of the host vehicle.

[0019] The acquisition unit acquires other vehicle information indicating the presence or absence of other vehicles traveling in an area measurable by the first measurement device in front of the traveling direction of the host vehicle, and when ending the deceleration of the host vehicle, the speed control unit, if the acquisition unit has acquired the other vehicle information indicating that no other vehicle is present, may increase the acceleration after ending the deceleration more than when the acquisition unit has acquired the other vehicle information indicating that an other vehicle is present.

[0020] The speed control method according to the second aspect of the present invention includes an acquisition step of acquiring, by a processor, a longitudinal distance, which is a distance between the position of an other vehicle traveling in front of the traveling direction of the host vehicle and the position of the host vehicle in the longitudinal direction of the host vehicle, from a first measurement device that identifies the position of the other vehicle based on a reflected wave of light waves or radio waves emitted to the other vehicle, a determination step of determining a first deceleration time for decelerating the host vehicle at a second deceleration smaller than a first deceleration for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed between the other vehicle and the host vehicle and the longitudinal distance at a first time, and a speed control step of decelerating the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerating the host vehicle at a third deceleration greater than the first deceleration at a time after the second time.

[0021] The program according to the third aspect of the present invention causes a processor to execute a step of acquiring a longitudinal distance, which is a distance between the position of an other vehicle traveling in front of the traveling direction of the host vehicle and the position of the host vehicle in the longitudinal direction of the host vehicle, from a first measurement device that identifies the position of the other vehicle based on a reflected wave of light waves or radio waves emitted to the other vehicle, a step of determining a first deceleration time for decelerating the host vehicle at a second deceleration smaller than a first deceleration for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed between the other vehicle and the host vehicle and the longitudinal distance at a first time, and a step of decelerating the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerating the host vehicle at a third deceleration greater than the first deceleration at a time after the second time.

Advantages of the Invention

[0022] According to the present invention, it has an effect of suppressing unnecessary deceleration.

Brief Description of the Drawings

[0023]

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Embodiments for Carrying Out the Invention

[0024] <Overview of the host vehicle S1> FIG. 1 is a diagram for explaining the overview of the host vehicle S1 according to the present embodiment. The host vehicle S1 shown in FIG. 1 includes a measurement system 10, a vehicle speed sensor 14, a drive source 21, a braking device 22, and a speed control device 30. The host vehicle S1 has ACC (Adaptive Cruise Control). ACC is a function in which, when the driver of the host vehicle S1 does not perform a driving operation related to the vehicle speed, the host vehicle S1 travels with the vehicle speed set by the driver as an upper limit value, or travels so that the distance between the host vehicle S1 and a preceding vehicle traveling ahead in the traveling direction of the host vehicle S1 becomes a predetermined distance. In the present embodiment, the operation when the host vehicle S1 travels by ACC will be described.

[0025] The measurement system 10 includes a first measurement device 11, a second measurement device 12, and a measurement control device 13. The measurement system 10 is a system for measuring the distance between the position of another vehicle with respect to the host vehicle S1 and the position of the host vehicle S1. In the present embodiment, the preceding vehicle is a vehicle that travels in the travel lane in which the host vehicle S1 travels in front of the traveling direction of the host vehicle S1, and does not include a vehicle that travels in an adjacent lane adjacent to the travel lane in which the host vehicle S1 travels in front of the traveling direction of the host vehicle S1. Further, in the present embodiment, the other vehicle includes the preceding vehicle and a vehicle that travels in an adjacent lane adjacent to the travel lane in which the host vehicle S1 travels in front of the traveling direction of the host vehicle S1.

[0026] The first measurement device 11 is, for example, RADAR (Radio Detection And Ranging), but may be LiDAR (Light Detection And Ranging). The first measurement device 11 specifies the position of another vehicle with respect to the host vehicle S1 based on the reflected wave of light waves or radio waves emitted to another vehicle traveling ahead in the traveling direction of the host vehicle S1. As an example, the position of another vehicle is the coordinates indicating the position of the center of the rear surface of the other vehicle in the width direction of the host vehicle S1 when the position of the center of the front surface of the host vehicle S1 in the width direction of the host vehicle S1, where the first measurement device 11 or the second measurement device 12 is provided, is taken as the origin.

[0027] The first measuring device 11 generates point cloud data based on, for example, a reflected wave of a light wave or a radio wave emitted to another vehicle, and extracts the outer contour line of the other vehicle from the point cloud data. Based on the extracted outer contour line, the first measuring device 11 specifies the position of the other vehicle in the longitudinal direction of the host vehicle S1 (hereinafter sometimes referred to as "longitudinal position") and the position of the other vehicle in the lateral direction of the host vehicle S1 (hereinafter sometimes referred to as "lateral position"). Based on the specified position of the other vehicle, the first measuring device 11 generates other vehicle information indicating the presence or absence of another vehicle traveling in the area measurable by the first measuring device 11, and notifies the measurement control device 13 of the longitudinal position and lateral position of the other vehicle and the other vehicle information. The first measuring device 11 generates vehicle identification information (hereinafter referred to as "vehicle ID") for identifying the other vehicle included in the extracted point cloud data, and notifies the measurement control device 13 of the longitudinal position and lateral position of the other vehicle and the vehicle ID. Note that the other vehicle information may include information indicating the presence or absence of an object other than a vehicle, and the vehicle ID may be generated as identification information for identifying an object other than a vehicle included in the point cloud data.

[0028] The second measuring device 12 is an imaging device such as a stereo camera, for example. The second measuring device 12 specifies the position of the other vehicle with respect to the host vehicle S1 based on an imaging image generated by imaging the front in the traveling direction of the host vehicle S1. The second measuring device 12 extracts, for example, the area of the other vehicle in the imaging area of the second measuring device 12 from the imaging image, and specifies the position of the center of the rear surface of the other vehicle in the lateral direction of the host vehicle S1, thereby specifying the longitudinal position and lateral position of the other vehicle. The second measuring device 12 notifies the measurement control device 13 of the specified longitudinal position and lateral position of the other vehicle.

[0029] The measurement control device 13 is a device including a processor such as one or more CPUs (Central Processing Units) or ECUs (Electronic Control Units), for example. The measurement control device 13 specifies the distance between the host vehicle S1 and the other vehicle based on the longitudinal position and the lateral position of the other vehicle acquired from the first measurement device 11 and the second measurement device 12. The distance between the host vehicle S1 and the other vehicle includes the distance between the host vehicle S1 and the other vehicle in the longitudinal direction of the host vehicle S1 (i.e., the "inter-vehicle distance", hereinafter referred to as the "longitudinal distance") and the distance between the host vehicle S1 and the other vehicle in the width direction of the host vehicle S1 (hereinafter referred to as the "lateral distance").

[0030] As an example, when the distance between the lateral position acquired from the first measurement device 11 and the lateral position acquired from the second measurement device 12 is less than a predetermined distance, the measurement control device 13 specifies the longitudinal distance and the lateral distance based on the longitudinal position acquired from the first measurement device 11 and the lateral position acquired from the second measurement device 12. The predetermined distance is, for example, half of the width of the lane in which the host vehicle S1 travels, or a fixed value such as 2 meters. On the other hand, when the distance between the lateral position acquired from the first measurement device 11 and the lateral position acquired from the second measurement device 12 is greater than or equal to the predetermined distance, the measurement control device 13 specifies the longitudinal distance and the lateral distance based on the longitudinal position and the lateral position acquired from the first measurement device 11.

[0031] The measurement control device 13 outputs the specified longitudinal distance and lateral distance to the speed control device 30 as the distance between the other vehicle and the host vehicle S1 with respect to the host vehicle S1. Further, the measurement control device 13 outputs the other vehicle information and the vehicle ID acquired from the first measurement device 11 to the speed control device 30 in association with the longitudinal distance and the lateral distance. Note that the measurement control device 13 may be included in the speed control device 30.

[0032] The vehicle speed sensor 14 is a sensor for detecting the vehicle speed of the host vehicle S1. The vehicle speed sensor 14 detects the vehicle speed of the host vehicle S1 at a predetermined cycle (for example, 0.1 second), and outputs it to the speed control device 30. The drive source 21 is an engine or a motor for driving the host vehicle S1. The braking device 22 is a device for decelerating or stopping the host vehicle S1, and includes, for example, a brake master cylinder and at least one of a disc brake and a drum brake.

[0033] Based on the distance between the other vehicle and the host vehicle S1 acquired from the measurement control device 13, the speed control device 30 identifies the preceding vehicle with respect to the host vehicle S1, and executes a process of determining a deceleration or an acceleration for making the distance between the host vehicle S1 and the preceding vehicle a predetermined distance. The preceding vehicle is another vehicle traveling in the lane in which the host vehicle S1 travels in front of the traveling direction of the host vehicle S1. When the speed control device 30 makes the deceleration of the host vehicle S1 greater than 0, it causes the braking device 22 to generate a braking force for generating the deceleration. When the speed control device 30 makes the acceleration of the host vehicle S1 greater than 0, it causes the drive source 21 to generate a driving force for generating the acceleration. The speed control device 30 may have a housing including electronic components, or may be a printed circuit board on which the electronic components are mounted.

[0034] By the way, when the host vehicle S1 travels inside or near a building, the first measurement device 11 may acquire reflected waves obtained by the light waves or radio waves emitted to another vehicle contacting and reflecting from the other vehicle from a plurality of propagation paths (so-called, multipath may occur). The building is, for example, a tunnel or a bridge, and the building is, for example, an office building or a condominium.

[0035] FIG. 2 is a diagram for explaining an example of multipath. In FIG. 2, a host vehicle S1, an other vehicle S2, a lane R1 on which the host vehicle S1 travels, a lane R2 adjacent to the lane R1, and walls N1 and N2 of a building or a structure are shown. In FIG. 2, it is assumed that the other vehicle S2 is traveling in the lane R2 (the position of the other vehicle S2 indicated by the solid line). As shown in FIG. 2, a first measuring device 11 provided in the host vehicle S1 obtains a reflected wave of a light wave or a radio wave emitted to the other vehicle S2 not only from a path K1 that travels linearly from the other vehicle S2 to the host vehicle S1, but also from a path K2 that travels from the other vehicle S2 to the host vehicle S1 via the wall N2, thereby causing multipath. When multipath occurs, the first measuring device 11 may erroneously identify the position of the other vehicle S2 as position F3.

[0036] When multipath does not occur, the measurement control device 13 uses the longitudinal position identified by the first measuring device 11 and the lateral position identified by the second measuring device 12 because the distance between the position F1 identified by the first measuring device 11 and the position F2 identified by the second measuring device 12 is less than the threshold value T. Then, in order for the measurement control device 13 to identify the longitudinal distance V and the lateral distance H1 between the host vehicle S1 and the other vehicle S2, the speed control device 30 can determine that the other vehicle S2 is traveling in the lane R2.

[0037] However, when multipath occurs, the measurement control device 13 uses the lateral position and the longitudinal position identified by the first measuring device 11 because the distance between the position F1 and the position F3 is greater than or equal to the threshold value T. As a result, in order for the measurement control device 13 to identify the longitudinal distance V and the lateral distance H2, the speed control device 30 erroneously determines that the other vehicle S2 is traveling in the lane R1 (the position of the other vehicle S2 indicated by the dotted line), which is the traveling lane of the host vehicle S1. Then, the speed control device 30 erroneously determines that the other vehicle S2 is a preceding vehicle in the traveling lane of the host vehicle S1, and decelerates the host vehicle S1 to travel at a predetermined longitudinal distance even though there is no preceding vehicle in front of the traveling direction of the host vehicle S1 in reality. For example, the speed control device 30 suddenly decelerates the host vehicle S1.

[0038] Therefore, when the speed control device 30 determines that the other vehicle S2 is a preceding vehicle with respect to the host vehicle S1, the speed control device 30 decelerates the host vehicle S1 at a second deceleration (hereinafter sometimes referred to as "gentle brake") that is smaller than the first deceleration for a predetermined time from the time of determination. The first deceleration is, for example, the deceleration that makes the relative speed of the host vehicle S1 with respect to the other vehicle S2 zero at the timing when the longitudinal distance between the host vehicle S1 and the other vehicle S2 becomes zero. Then, at the time after the elapse of the predetermined time, the speed control device 30 decelerates the host vehicle S1 at a third deceleration (hereinafter sometimes referred to as "normal brake") that is larger than the first deceleration.

[0039] By operating as described above, the speed control device 30 can re-determine whether the other vehicle S2 is a preceding vehicle when the host vehicle S1 is executing a gentle brake. And, for example, when the speed control device 30 re-determines that the other vehicle S2 is not a preceding vehicle due to the elimination of the multipath, the speed control device 30 can accelerate the host vehicle S1. As a result, the speed control device 30 can suppress unnecessary deceleration or shorten the time for accelerating the host vehicle S1 to the vehicle speed of the host vehicle S1 at the time of misjudgment, compared with executing a normal brake from the time of misjudging that the other vehicle S2 is a preceding vehicle. Hereinafter, the configuration and operation of the speed control device 30 will be described in detail.

[0040] <Configuration of Speed Control Device 30> As shown in FIG. 1, the speed control device 30 includes a storage unit 31 and a control unit 32. The control unit 32 includes an acquisition unit 321, a determination unit 322, and a speed control unit 323.

[0041] The storage unit 31 has a storage medium such as, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), an HDD (Hard Disk Drive), or an SSD (Solid State Drive). The storage unit 31 stores a program executed by the control unit 32. The storage unit 31 stores various types of information for identifying a preceding vehicle with respect to the host vehicle S1 or determining the deceleration or acceleration of the host vehicle S1.

[0042] The control unit 32 is, for example, a processor such as a CPU or an ECU. By executing the program stored in the storage unit 31, the control unit 32 functions as an acquisition unit 321, a determination unit 322, and a speed control unit 323. When the measurement control device 13 is included in the speed control device 30, the control unit 32 may function as the acquisition unit 321, the determination unit 322, the speed control unit 323, and the measurement control device 13 by executing the program stored in the storage unit 31. Note that the control unit 32 may be constituted by one processor, or may be constituted by a combination of a plurality of processors or one or more processors and an electronic circuit. Hereinafter, the configuration of each unit realized by the control unit 32 will be described.

[0043] The acquisition unit 321 acquires a longitudinal distance, which is the inter-vehicle distance between the position of the other vehicle S2 traveling ahead in the traveling direction of the host vehicle S1 and the position of the host vehicle S1 in the longitudinal direction of the host vehicle S1, from the first measurement device 11. The acquisition unit 321 acquires a first lateral distance between the position of the other vehicle S2 and the position of the host vehicle S1 in the width direction of the host vehicle S1, which is measured by the first measurement device 11.

[0044] The acquisition unit 321 may acquire other vehicle information from the first measurement device 11. The other vehicle information is information indicating the presence or absence of the other vehicle S2 traveling in the area measurable by the first measurement device 11 ahead in the traveling direction of the host vehicle S1 (that is, information indicating that the other vehicle S2 has been extracted from the point cloud data). The acquisition unit 321 acquires, for example, at least one of the longitudinal distance and the first lateral distance and the other vehicle information from the first measurement device 11 at a predetermined period. The predetermined period is, for example, a fixed value less than 1 second. The acquisition unit 321 may acquire a vehicle ID for identifying the other vehicle from the first measurement device 11 in association with the longitudinal distance or the first lateral distance. The acquisition unit 321 acquires, for example, at least one of the longitudinal distance and the first lateral distance and the vehicle ID from the first measurement device 11 at a predetermined period.

[0045] The acquisition unit 321 acquires a second lateral distance different from the first lateral distance from the second measurement device 12. The second lateral distance is the distance between the position of the other vehicle S2 and the position of the host vehicle S1 in the width direction of the host vehicle S1 measured by the second measurement device 12. The acquisition unit 321 may acquire the longitudinal distance between the host vehicle S1 and the other vehicle S2 from the second measurement device 12.

[0046] The acquisition unit 321 acquires the vehicle speed of the host vehicle S1 from the vehicle speed sensor 14. For example, the acquisition unit 321 acquires the vehicle speed of the host vehicle S1 from the vehicle speed sensor 14 at a predetermined cycle. The acquisition unit 321 may store the longitudinal distance, the first lateral distance, the other vehicle information, and the vehicle ID acquired from the first measurement device 11, the longitudinal distance and the second lateral distance acquired from the second measurement device 12, and the vehicle speed acquired from the vehicle speed sensor 14 in the storage unit 31.

[0047] The determination unit 322 determines a gentle braking time (first deceleration time) for decelerating with gentle braking (second deceleration). The determination unit 322 determines a gentle braking time for decelerating with a second deceleration (gentle braking) smaller than the first deceleration based on the relative speed and the longitudinal distance between the other vehicle S2 and the host vehicle S1 at the first time. The first time is the time when the acquisition unit 321 acquires other vehicle information indicating the presence of the other vehicle S2 (that is, the time when it is specified that the other vehicle S2 exists in front of the traveling direction of the host vehicle S1). The relative speed is, for example, a subtraction value obtained by subtracting the vehicle speed of the host vehicle S1 from the vehicle speed of the other vehicle S2. The first deceleration is the deceleration for making the relative speed of the host vehicle S1 with respect to the other vehicle S2 zero at the timing when the longitudinal distance between the other vehicle S2 and the host vehicle S1 becomes zero (that is, the deceleration for making the vehicle speed of the host vehicle S1 the same as the vehicle speed of the other vehicle S2 at the timing when the host vehicle S1 contacts the other vehicle S2).

[0048] The determination unit 322 calculates the relative speed at the first time based on the longitudinal distances at a plurality of times including the first time, for example. The determination unit 322 determines a first target deceleration, which is the upper limit value of the deceleration of gentle braking corresponding to the calculated relative speed and longitudinal distance, by referring to target deceleration information indicating the target deceleration corresponding to the relative speed and the longitudinal distance stored in the storage unit 31.

[0049] FIG. 3 is a diagram showing an example of target deceleration information stored in the storage unit 31. FIG. 3(a) is address information indicating an address in the storage unit 31 where target decelerations corresponding to the relative speed and the vertical distance are stored. FIG. 3(b) is the target deceleration stored in the area indicated by the address included in FIG. 3(a) within the storage unit 31. The horizontal axis of FIG. 3(a) indicates the vertical distance, and the vertical axis of FIG. 3(a) indicates the relative speed. As shown in FIG. 3(a), the area D1 of the address information includes an address in the storage unit 31 where a target deceleration for the speed control unit 323 to decelerate the host vehicle S1 when the relative speed is less than 0 is stored. Also, the area D2 may or may not include an address in the storage unit 31 that stores a target acceleration (the upper limit value of the acceleration) for the speed control unit 323 to accelerate the host vehicle S1 when the relative speed is greater than 0.

[0050] The determination unit 322 refers to the address information stored in the storage unit 31 to identify an address where the target deceleration corresponding to the relative speed and the inter-vehicle speed is stored, and accesses the address in the storage unit 31 to obtain the target deceleration. Specifically, the determination unit 322 refers to the address information shown in FIG. 3(a) to identify an address D11 of an area where the target deceleration corresponding to the vertical distance C11 and the relative speed E11 is stored. The determination unit 322 accesses the address D11 shown in FIG. 3(b) to obtain the target deceleration "1.0 m / s 2 " stored at the address D11.

[0051] Subsequently, the determination unit 322 determines the deceleration time so that the deceleration of the host vehicle S1 reaches the first target deceleration during the deceleration time. For example, based on the calculated relative speed and longitudinal distance, the determination unit 322 determines the deceleration time until the first target deceleration is reached so that when decelerating with normal braking, the host vehicle S1 does not contact the other vehicle S2 at a predetermined longitudinal distance. The predetermined longitudinal distance is, for example, a distance determined according to the vehicle speed of the preceding vehicle and is stored in the storage unit 31. As an example, the determination unit 322 refers to a deceleration time map stored in the storage unit 31 that indicates the deceleration time corresponding to the relative speed, longitudinal distance, and the first target deceleration, and determines the deceleration time corresponding to the calculated relative speed and longitudinal distance and the first target deceleration.

[0052] The determination unit 322 may determine the standby time from the first time until the time to start decelerating with deceleration braking (second deceleration) based on the relative speed and longitudinal distance at the first time. For example, the determination unit 322 refers to a standby time map stored in the storage unit 31 that indicates the standby time corresponding to the relative speed and longitudinal distance, and determines the standby time corresponding to the longitudinal distance and relative speed between the host vehicle S1 and the other vehicle S2. By determining the standby time in this way, the speed control unit 323 can execute deceleration braking after the standby time has elapsed. Details of the standby time will be described later.

[0053] The determination unit 322 may determine the normal braking time (second deceleration time) to decelerate with normal braking (third deceleration) after the deceleration time has elapsed. The determination unit 322 determines the normal braking time to decelerate with the third deceleration (normal braking) based on the relative speed and longitudinal distance at the first time. For example, by referring to the target deceleration information stored in the storage unit 31, the determination unit 322 determines the second target deceleration, which is the upper limit value of normal braking, corresponding to the relative speed and longitudinal distance at the first time, and determines the normal braking time so that the deceleration of the host vehicle S1 reaches the second target deceleration.

[0054] The determination unit 322 determines the normal braking time such that, for example, after the deceleration of the host vehicle S1 reaches the second target deceleration, the distance between the host vehicle S1 and the preceding vehicle becomes a predetermined longitudinal distance at which they do not contact. As an example, the determination unit 322 refers to a normal braking time map stored in the storage unit 31, which shows the normal braking time corresponding to the longitudinal distance and relative speed with the preceding vehicle, and the second target deceleration, to determine the normal braking time corresponding to the longitudinal distance and relative speed with the preceding vehicle, and the second target deceleration.

[0055] The speed control unit 323 determines the acceleration or deceleration of the host vehicle S1 based on the relative speed and longitudinal distance between the host vehicle S1 and the preceding vehicle. The speed control unit 323 controls the vehicle speed of the host vehicle S1 by causing the drive source 21 to generate a driving force corresponding to the determined acceleration or causing the braking device 22 to generate a braking force corresponding to the determined deceleration. The speed control unit 323 determines whether a preceding vehicle of the host vehicle S1 exists at a predetermined cycle. The speed control unit 323 determines, for example, whether another vehicle S2 is traveling in the lane in which the host vehicle S1 is traveling in the forward direction of travel based on other vehicle information and the first lateral distance.

[0056] For example, when the acquisition unit 321 acquires other vehicle information indicating the existence of another vehicle S2 and the position corresponding to the first lateral distance is included in the area of the travel lane of the host vehicle S1, the speed control unit 323 determines that the other vehicle S2 is the preceding vehicle in the travel lane of the host vehicle S1. Subsequently, the speed control unit 323 determines the acceleration or deceleration based on the relative speed and longitudinal distance between the host vehicle S1 and the other vehicle S2, and controls the vehicle speed of the host vehicle S1 by accelerating or decelerating the host vehicle S1. On the other hand, when the acquisition unit 321 acquires other vehicle information indicating the non-existence of the other vehicle S2 or the position corresponding to the first lateral distance is not included in the area of the travel lane of the host vehicle S1, the speed control unit 323 determines that there is no preceding vehicle for the host vehicle S1. Subsequently, the speed control unit 323 controls the vehicle speed of the host vehicle S1 with the vehicle speed set by the driver as the upper limit value.

[0057] When it is determined that the other vehicle S2 is the leading vehicle in the driving lane of the host vehicle S1, the speed control unit 323 decelerates the host vehicle S1 with a gentle brake (second deceleration) from the first time until the second time when the gentle brake time (first deceleration time) has elapsed. Subsequently, at times after the second time, the speed control unit 323 decelerates the host vehicle S1 with a normal brake (third deceleration) that is greater than the first deceleration (i.e., the deceleration for making the vehicle speed of the host vehicle S1 the same as that of the leading vehicle). The time after the second time is, for example, the normal brake time (second deceleration time) determined by the determination unit 322.

[0058] By operating in this manner, the speed control unit 323 can re-determine whether the other vehicle S2 is the leading vehicle during the gentle brake time. And when the speed control unit 323 determines in the re-determination that the other vehicle S2 is not the leading vehicle, it can accelerate to return to the vehicle speed before executing the gentle brake. As a result, since the vehicle speed of the host vehicle S1 does not decrease more than when executing the normal brake from the first time, the time to return to the vehicle speed before executing the gentle brake can be reduced. Furthermore, since the change amount of the vehicle speed of the host vehicle S1 can be suppressed more than when executing the normal brake from the first time, the discomfort given to the driver can be reduced. Also, since the normal brake is executed at times after the second time, even when it is correctly determined that the other vehicle S2 is the leading vehicle, the host vehicle S1 can be decelerated so that the longitudinal distance from the leading vehicle becomes a predetermined longitudinal distance.

[0059] The speed control unit 323 determines the change amount of the gentle brake per unit time so that the deceleration of the host vehicle S1 reaches the first target deceleration determined by the determination unit 322 during the gentle brake time. The speed control unit 323 calculates, for example, based on the relative speed and the longitudinal distance, the change amount of the gentle brake per unit time until the first target deceleration is reached so that the host vehicle S1 does not contact the other vehicle S2 even if decelerated with a normal brake during the gentle brake time and a predetermined longitudinal distance is obtained. By operating in this manner, the speed control unit 323 can maintain a predetermined longitudinal distance, for example, even if the other vehicle S2 suddenly decelerates.

[0060] During the gentle braking time, the speed control unit 323 may decelerate the host vehicle S1 with the gentle braking determined by referring to the gentle braking change amount map (first change amount map) stored in the storage unit 31. The gentle braking change amount map is a map showing the change amount of gentle braking per unit time corresponding to the relative speed and the longitudinal distance. The speed control unit 323 determines, for example, the change amount of gentle braking corresponding to the relative speed and the longitudinal distance at a predetermined time by referring to the gentle braking change amount map. The speed control unit 323 determines the gentle braking at a predetermined time based on the gentle braking (second deceleration) at a time one unit time before the predetermined time and the determined change amount of gentle braking.

[0061] During the normal braking time, the speed control unit 323 determines the change amount of normal braking per unit time so that the deceleration of the host vehicle S1 reaches the second target deceleration determined by the determination unit 322. The speed control unit 323 calculates, for example, the change amount of normal braking per unit time until the second target deceleration is reached so that the host vehicle S1 does not contact the other vehicle S2 even when decelerating at the maximum value of normal braking during the normal braking time, based on the relative speed and the longitudinal distance, to a predetermined longitudinal distance.

[0062] During the normal braking time, the speed control unit 323 may decelerate the host vehicle S1 with the normal braking determined by referring to the normal braking change amount map (second change amount map) stored in the storage unit 31. The normal braking change amount map is a map showing the change amount of normal braking per unit time corresponding to the relative speed and the longitudinal distance. The change amount included in the normal braking change amount map indicates a larger change amount than the change amount included in the gentle braking change amount map. The speed control unit 323 determines, for example, the change amount of normal braking corresponding to the relative speed and the longitudinal distance at a predetermined time by referring to the normal braking change amount map. The speed control unit 323 determines the normal braking at a predetermined time based on the normal braking (third deceleration) at a time one unit time before the predetermined time and the determined change amount of normal braking.

[0063] Further, the speed control unit 323 decelerates the host vehicle S1 so that the normal brake reaches the second target deceleration during the normal brake time. For example, when the sum of the normal brake at a time unit time before a predetermined time and the change amount of the normal brake determined at the predetermined time does not reach the second target deceleration, the speed control unit 323 determines the sum as the normal brake at the predetermined time. On the other hand, when the sum reaches the second target deceleration, the speed control unit 323 determines the second target deceleration as the normal brake. By operating in this way, the speed control unit 323 can decelerate the host vehicle S1 so that the normal brake reaches the second target deceleration during the normal brake time and can decelerate the host vehicle S1 so that the normal brake does not exceed the second target deceleration.

[0064] The host vehicle S1 increases the longitudinal distance from the preceding vehicle as the vehicle speed of the host vehicle S1 increases, and decreases the longitudinal distance from the preceding vehicle as the vehicle speed of the host vehicle S1 decreases. When the longitudinal distance between the host vehicle S1 and the preceding vehicle is short, if the host vehicle S1 executes the normal brake after executing the gentle brake, there is a risk that the host vehicle S1 cannot decelerate in time and the host vehicle S1 and the preceding vehicle will come into contact.

[0065] Therefore, for example, when the vehicle speed is less than the first threshold value, the speed control unit 323 decelerates the host vehicle S1 with the normal brake at a time after the first time. That is, when the vehicle speed is less than the first threshold value, the speed control unit 323 executes the normal brake without executing the gentle brake. On the other hand, when the vehicle speed is greater than or equal to the first threshold value, the speed control unit 323 decelerates the host vehicle S1 with the gentle brake during the gentle brake time from the first time, and decelerates the host vehicle S1 with the normal brake at a time after the time when the gentle brake time has elapsed. The first threshold value is the vehicle speed when driving in an urban area, for example, 30 km / h. By operating in this way, the speed control unit 323 can safely decelerate the host vehicle S1 according to the lane in which the host vehicle S1 travels.

[0066] Incidentally, when multipath occurs in the propagation path of the reflected wave of the light wave or radio wave acquired by the first measuring device 11, the acquisition unit 321 may acquire an incorrect first lateral distance, so that the speed control unit 323 may incorrectly identify the position of the other vehicle S2 and erroneously determine the other vehicle S2 as the preceding vehicle. In contrast, although the speed control unit 323 may be able to correctly determine whether the other vehicle S2 is the preceding vehicle by re-determining at a predetermined cycle, the time required for correct determination may be longer than the creep braking time. Therefore, the speed control unit 323 decelerates the host vehicle S1 by creep braking from the time when the standby time determined by the determination unit 322 has elapsed to the creep braking time. Hereinafter, an outline of the operation of the host vehicle S1 during the standby time and the creep braking time will be described.

[0067] FIGS. 4 and 5 are diagrams showing the operation of the host vehicle S1 that correctly determines the presence of the preceding vehicle and decelerates. FIG. 4 is a diagram showing the positions of the host vehicle S1 and the other vehicle S2, and FIG. 5 is a diagram showing the operation of the host vehicle S1 decelerating. In FIG. 4, the host vehicle S1, the other vehicle S2 (i.e., the preceding vehicle), the lane R1 in which the host vehicle S1 and the preceding vehicle travel, the lane R2 adjacent to the lane R1, and the walls N1 and N2 of the building or structure are shown. The horizontal axis in FIG. 5 represents time, and the vertical axis in FIG. 5 represents "preceding vehicle determination" indicating the result of determining the presence of the preceding vehicle, "deceleration control" indicating the state of the decelerating operation, "deceleration" and "vehicle speed". In the deceleration and vehicle speed shown in FIG. 5, the solid line indicates the operation of the host vehicle S1 considering the standby time and the creep braking time, the dotted line indicates the operation of the host vehicle S1 not considering the standby time and the creep braking time (i.e., decelerating by normal braking from the first time), and the dashed-dotted line indicates the operation of the other vehicle S2.

[0068] As shown in Fig. 4, in front of the traveling direction of the host vehicle S1 traveling in the lane R1 at a speed of 100 km / h, another vehicle S2 is traveling in the lane R1 at a speed of 90 km / h. At the time T11 (the first time) in Fig. 5, the speed control unit 323 correctly determines that there is a preceding vehicle (another vehicle S2) in front of the host vehicle S1 shown in Fig. 4 in the traveling direction. When not considering the waiting time and the gentle braking time, the speed control unit 323 makes the vehicle speed of the host vehicle S1 coincide with the vehicle speed of the preceding vehicle at the time T12. That is, at the time T12, the operation of decelerating the host vehicle S1 is terminated, and the host vehicle S1 is made to travel so that the distance between the preceding vehicle and the host vehicle S1 becomes a predetermined distance.

[0069] On the other hand, when considering the waiting time and the gentle braking time, the speed control unit 323 does not decelerate the host vehicle S1 during the waiting time from the time T11 to the time T12, and maintains the vehicle speed V0. Then, the speed control unit 323 decelerates the host vehicle S1 with gentle braking during the gentle braking time from the time T12 to the time T13, and decelerates the host vehicle S1 with normal braking during the normal braking time from the time T13 to the time T14.

[0070] Figs. 6 and 7 are diagrams showing the operation of the host vehicle S1 when erroneously determining the presence of a preceding vehicle. Fig. 6 is a diagram showing the positions of the host vehicle S1 and another vehicle S2, and Fig. 7 is a diagram showing the operation of the host vehicle S1 decelerating. In Fig. 6, different from Fig. 4 in that the other vehicle S2 shown by the solid line is shown in the area of the lane R2, and the other vehicle S2 shown by the dotted line is shown in the area of the lane R1, and the other points are the same. Regarding the horizontal axis and the vertical axis in Fig. 7, the solid line, the dotted line, and the one-dot chain line in the deceleration and the vehicle speed shown in Fig. 7 are the same as those in Fig. 5.

[0071] As shown in Fig. 6, in front of the traveling direction of the host vehicle S1 traveling in the lane R1 at a speed of 100 km / h, the other vehicle S2 shown by the solid line is traveling in the lane R2 adjacent to the lane R1 at a speed of 90 km / h. At the time T21 (the first time) in Fig. 7, based on the first lateral distance acquired from the acquisition unit 321, the speed control unit 323 erroneously specifies that the position of the other vehicle S2 shown by the solid line in Fig. 6 is the position of the other vehicle S2 shown by the dotted line in Fig. 6, and erroneously determines that the other vehicle S2 is a preceding vehicle.

[0072] When the speed control unit 323 does not consider the standby time and the creep braking time, it starts decelerating with normal braking from time T21, and makes the vehicle speed V0 of the host vehicle S1 match the vehicle speed V2 of the other vehicle S2 at time T23. Then, when it is re-determined at time T24 that the other vehicle S2 is not the preceding vehicle of the host vehicle S1, the speed control unit 323 changes the vehicle speed V2 to the vehicle speed V0 by accelerating the host vehicle S1 during the time from time T24 to time T26.

[0073] On the other hand, when considering the standby time and the creep braking time, the speed control unit 323 does not decelerate the host vehicle S1 during the standby time from time T21 to time T22, and maintains the vehicle speed V0. Then, during the creep braking time from time T22, the speed control unit 323 decelerates the host vehicle S1 with creep braking. When it is re-determined at time T24 that the other vehicle S2 is not the preceding vehicle of the host vehicle S1, the speed control unit 323 changes the vehicle speed V1 to the vehicle speed V0 by accelerating the host vehicle S1 during the time from time T24 to time T25.

[0074] As described above, the speed control unit 323 can increase the time for re-determining whether the other vehicle S2 is the preceding vehicle or not by decelerating the host vehicle S1 with creep braking from the time after the standby time has elapsed. That is, the speed control unit 323 can re-determine whether the other vehicle S2 is the preceding vehicle or not during the standby time and the creep braking time. As a result, since the number of times of re-determination increases, the accuracy of determining whether the other vehicle S2 is the preceding vehicle or not can be improved. The outline of the operation of the host vehicle S1 during the standby time and the creep braking time has been described above.

[0075] When the relative speed obtained by subtracting the vehicle speed of the host vehicle S1 from the vehicle speed of another vehicle S2 is greater than 0, the speed control unit 323 does not require a waiting time before starting to decelerate the host vehicle S1 in order to accelerate the host vehicle S1. Therefore, for example, when the relative speed calculated based on the longitudinal distances acquired by the acquisition unit 321 at a plurality of times including the first time is greater than 0, the speed control unit 323 accelerates the host vehicle S1 without providing a waiting time. By operating in this manner, the speed control unit 323 can quickly accelerate the host vehicle S1. On the other hand, when the relative speed at the first time indicates that the speed of the host vehicle S1 is greater than the speed of the other vehicle S2 (that is, when the relative speed is less than 0), the speed control unit 323 decelerates the host vehicle S1 at the second deceleration rate from the time when the waiting time has elapsed. By operating in this manner, the speed control unit 323 can provide a waiting time only when decelerating the host vehicle S1.

[0076] For example, on a road with a high speed limit such as a highway, the host vehicle S1 increases the longitudinal distance from the preceding vehicle, and on a road with a low speed limit such as a general road, the host vehicle S1 shortens the longitudinal distance from the preceding vehicle. When the longitudinal distance between the host vehicle S1 and the preceding vehicle is short, if the host vehicle S1 executes a gentle brake after the waiting time has elapsed and then executes a normal brake, there is a risk that the host vehicle S1 and the preceding vehicle will come into contact because the deceleration of the host vehicle S1 is not in time.

[0077] Therefore, for example, when the vehicle speed acquired by the acquisition unit 321 from the vehicle speed sensor 14 at the first time is equal to or higher than the third threshold value, the speed control unit 323 decelerates the host vehicle S1 with a gentle brake during the gentle brake time from the time when the waiting time has elapsed. On the other hand, when the vehicle speed is less than the third threshold value, the speed control unit 323 decelerates the host vehicle S1 with a gentle brake from the first time during the gentle brake time without providing a waiting time. The third threshold value is a value indicating a vehicle speed higher than the first threshold value and corresponding to the minimum speed of a highway, and is, for example, 50 km / h. By operating in this manner, when the longitudinal distance makes it difficult to provide a waiting time, the speed control unit 323 can decelerate the host vehicle S1 without providing a waiting time.

[0078] By the way, when a multipath occurs in the propagation path of the reflected wave of the light wave or radio wave acquired by the first measuring device 11, the acquisition unit 321 acquires, from the first measuring device 11, a first lateral distance corresponding to the position of the wrong other vehicle S2. Therefore, when a multipath occurs, the difference between the first lateral distance acquired from the first measuring device 11 and the second lateral distance acquired from the second measuring device 12 becomes larger than when no multipath occurs.

[0079] Therefore, for example, after a waiting time has elapsed, when the difference between the first lateral distance and the second lateral distance is equal to or greater than a second threshold value, the speed control unit 323 does not decelerate the host vehicle S1. The second threshold value is, for example, a distance equal to half the width of the lane in which the host vehicle S1 travels. By operating in this way, the speed control unit 323 can determine with high accuracy whether the other vehicle S2 is the preceding vehicle of the host vehicle S1. Furthermore, by performing re-determination as to whether the other vehicle S2 is the preceding vehicle of the host vehicle S1 using the difference between the first lateral distance and the second lateral distance, the accuracy of re-determination during the waiting time can be improved.

[0080] The host vehicle S1 may have a preceding vehicle changed when the preceding vehicle changes the travel lane or when another vehicle moves between the host vehicle S1 and the preceding vehicle. Also, even when the other vehicle does not change lanes or move between the host vehicle S1 and the preceding vehicle, there may be a case where it is erroneously determined that another vehicle has moved between the host vehicle S1 and the preceding vehicle due to the occurrence of a multipath.

[0081] FIG. 8 is a diagram for explaining an operation of erroneously determining that the preceding vehicle has changed. In FIG. 8, unlike FIG. 4, another vehicle S3 shown by a solid line is shown in the area of lane R2, and another vehicle S3 shown by a dotted line is shown in the area of lane R1, and the other points are the same. As shown in FIG. 8, in front of the traveling direction of the host vehicle S1 traveling at 100 km / h in lane R1, another vehicle S2 is traveling at 100 km / h. In lane R2, another vehicle S3 is traveling at 90 km / h. In this case, based on the first lateral distance acquired from the acquisition unit 321, the speed control unit 323 may erroneously identify the position of another vehicle S3 shown by a solid line in FIG. 8 as the position of another vehicle S3 shown by a dotted line in FIG. 8, and may erroneously determine that the preceding vehicle has changed from another vehicle S2 to another vehicle S3.

[0082] Therefore, from the first time when the preceding vehicle has changed from another vehicle S2 to another vehicle S3 until the standby time, the speed control unit 323 does not decelerate the host vehicle S1 and re-determines whether another vehicle S3 is the preceding vehicle. FIG. 9 is a diagram for explaining an operation when the preceding vehicle has changed. The horizontal axis and vertical axis of FIG. 9, the solid line, dotted line, and one-dot chain line in the deceleration and vehicle speed shown in FIG. 9 are the same as those in FIG. 5.

[0083] Before the time T31 (the first time) shown in FIG. 9, the host vehicle S1 shown in FIG. 8 is traveling behind another vehicle S2 (the preceding vehicle) shown in FIG. 8 at the same vehicle speed as another vehicle S2. At time T31, the speed control unit 323 erroneously determines that the preceding vehicle has changed from another vehicle S2 shown in FIG. 8 to another vehicle S3. If the standby time is not considered, the speed control unit 323 decelerates the host vehicle S1 with a normal brake from time T31. Then, at time T32, the speed control unit 323 re-determines that the preceding vehicle is another vehicle S2 instead of another vehicle S3, and accelerates the host vehicle S1.

[0084] On the one hand, when considering the waiting time, the determination unit 322 determines the waiting time W1 at time T31, and the speed control unit 323 maintains the vehicle speed V0 without decelerating the host vehicle S1 during the waiting time from time T31. Then, at time T32, which is a time before the end of the waiting time, when the speed control unit 323 re-determines that the leading vehicle is the other vehicle S2 instead of the other vehicle S3, the speed control unit 323 maintains the vehicle speed V0 at a time after time T32. By operating in this way, the speed control unit 323 can suppress unnecessary deceleration even when it is erroneously determined that the leading vehicle has changed.

[0085] Furthermore, even when the speed control unit 323 determines that the leading vehicle has changed after identifying the leading vehicle, the speed control unit 323 may determine the deceleration of the host vehicle S1 using the longitudinal distance acquired by the acquisition unit 321 at a time before the time when it is determined that the leading vehicle has changed. For example, during the waiting time or the gentle braking time, when the first vehicle ID at a predetermined time is different from the second vehicle ID at a time before the predetermined time, the speed control unit 323 decelerates the host vehicle S1 at a deceleration based on the relative speed and the longitudinal distance associated with the first vehicle ID.

[0086] FIG. 10 is a diagram for explaining the operation when the leading vehicle changes. The horizontal axis and the vertical axis in FIG. 10, and the solid line, the dotted line, and the one-dot chain line in the deceleration and the vehicle speed shown in FIG. 7 are the same as those in FIG. 5. Before the time T41 (the first time) shown in FIG. 10, the host vehicle S1 shown in FIG. 8 is traveling behind the other vehicle S2 (the leading vehicle) shown in FIG. 8 at the same vehicle speed as the other vehicle S2. At time T41, the speed control unit 323 erroneously determines that the leading vehicle has changed from the other vehicle S2 shown in FIG. 8 to the other vehicle S3. When not considering the waiting time and the gentle braking time, the speed control unit 323 decelerates with normal braking from time T41. Then, at time T43, when the speed control unit 323 re-determines that the leading vehicle is the other vehicle S2 instead of the other vehicle S3, the speed control unit 323 accelerates the host vehicle S1 from the vehicle speed V2 to the vehicle speed V0 during the time from time T43 to time T45.

[0087] On the other hand, when considering the waiting time and the creep braking time, the speed control unit 323 identifies that the vehicle ID indicating the other vehicle S3 acquired at time T41 is different from the vehicle ID indicating the other vehicle S2 acquired at a time before time T41. The determination unit 322 calculates the relative speed based on a plurality of longitudinal distances associated with the vehicle ID indicating the other vehicle S2 acquired at a time before time T41 during the waiting time from time T41 to time T42 and the creep braking time B1 determined by the determination unit 322. Then, the speed control unit 323 determines the creep braking (second deceleration) based on the longitudinal distance associated with the vehicle ID indicating the other vehicle S2 acquired at a time before time T41 and the calculated relative speed during the time from time T42 to time T43, and decelerates the host vehicle S1.

[0088] By operating in this way, even when the speed control unit 323 erroneously determines that the leading vehicle of the host vehicle S1 has changed, the deceleration of the host vehicle S1 can be determined using the longitudinal distance acquired at the time when the leading vehicle of the host vehicle S1 was correctly determined. As a result, the speed control unit 323 can suppress decelerating the host vehicle S1 based on the longitudinal distance between the host vehicle S1 and another vehicle due to, for example, an erroneous determination that another vehicle has moved between the leading vehicle and the host vehicle S1, and thus can suppress unnecessary deceleration of the host vehicle S1.

[0089] During the waiting time and the creep braking time, the speed control unit 323 determines, at a predetermined cycle, whether or not the other vehicle S2 traveling ahead in the traveling direction of the host vehicle S1 is the leading vehicle, or whether or not the leading vehicle has changed. Therefore, when a change in the leading vehicle occurs during measurement of the elapsed time of the waiting time or the creep braking time, the waiting time or the creep braking time for the changed leading vehicle becomes shorter than the waiting time or the creep braking time determined by the determination unit 322.

[0090] Therefore, when the speed control unit 323 re-determines that another vehicle S2, which was previously determined to be the leading vehicle, is not the leading vehicle, or determines that the leading vehicle has changed, it re-measures the elapsed time in the waiting time or the gentle braking time determined by the determination unit 322. That is, when a change in the leading vehicle occurs, the speed control unit 323 initializes (sets to zero) the measurement of the elapsed time in the waiting time or the gentle braking time, thereby extending the waiting time or the gentle braking time.

[0091] For example, in the waiting time, when the vehicle ID acquired at a predetermined time is different from the vehicle ID acquired at a time before the predetermined time, the speed control unit 323 starts decelerating the host vehicle S1 with gentle braking at the time when the waiting time has elapsed since the predetermined time. For example, in the waiting time, the speed control unit 323 re-measures the waiting time from the time when the vehicle indicated by the vehicle ID acquired by the acquisition unit 321 changes at a predetermined cycle (that is, the time when it changes to a new leading vehicle). The speed control unit 323 starts decelerating the host vehicle S1 with gentle braking at the time when the re-measured waiting time (elapsed time) has elapsed the waiting time determined by the determination unit 322.

[0092] FIG. 11 is a diagram showing an operation of initializing the waiting time or the gentle braking time. FIG. 11(a) shows the operation of initializing the waiting time, and FIG. 11(b) shows the operation of initializing the gentle braking time. The horizontal axis of FIG. 11 indicates time, and the vertical axis of FIG. 11 indicates "leading vehicle determination" and "deceleration control" shown in FIG. 5.

[0093] Specifically, as shown in FIG. 11(a), at time T51, the speed control unit 323 determines that the preceding vehicle of the host vehicle S1 is the other vehicle S2. From time T51, the speed control unit 323 maintains the vehicle speed of the host vehicle S1 without decelerating the host vehicle S1 during the waiting time W1 determined by the determination unit 322. At time T52, since the preceding vehicle is changed from the other vehicle S2 to the other vehicle S3, the speed control unit 323 extends the waiting time so as to maintain the vehicle speed of the host vehicle S1 without decelerating the host vehicle S1 during the waiting time W1 from time T52. At time T54, the speed control unit 323 starts to decelerate the host vehicle S1 by means of a gentle brake. By operating in this manner, the speed control unit 323 can provide the waiting time determined by the determination unit 322 for the changed preceding vehicle even if the preceding vehicle changes during the waiting time.

[0094] For example, when the vehicle ID acquired at a time before a predetermined time is different from the vehicle ID acquired at the predetermined time, the speed control unit 323 decelerates the host vehicle S1 by means of a gentle brake from the predetermined time for the gentle brake time. For example, during the gentle brake time, when the vehicle indicated by the vehicle ID acquired by the acquisition unit 321 changes at a predetermined cycle (that is, the time when the vehicle is changed to a new preceding vehicle), the speed control unit 323 remeasures the gentle brake time from that time. When the elapsed time of the remeasured gentle brake reaches the time when the gentle brake time determined by the determination unit 322 has elapsed, the speed control unit 323 starts to decelerate the host vehicle S1 by means of a normal brake.

[0095] Specifically, as shown in Fig. 11(b), at time T61, the speed control unit 323 determines that the leading vehicle of the host vehicle S1 is another vehicle S2, and from time T61, decelerates the host vehicle S1 with a gentle brake for the gentle brake time B1 determined by the determination unit 322. At time T62, since the leading vehicle is changed from another vehicle S2 to another vehicle S3, from time T62, the host vehicle S1 is decelerated with a gentle brake for the gentle brake time B1. At time T64, the speed control unit 323 starts to decelerate the host vehicle S1 with a normal brake. By operating in this way, even if the leading vehicle changes during the gentle brake time, the gentle brake time determined by the determination unit 322 can be provided for the changed leading vehicle.

[0096] The speed control unit 323 may decelerate the host vehicle S1 with a gentle brake for the gentle brake time from the time when it is detected that the difference between the first lateral distance and the second lateral distance is equal to or greater than the second threshold value. For example, when the difference between the first lateral distance and the second lateral distance is equal to or greater than the second threshold value, the speed control unit 323 re-determines that another vehicle S2 determined as the leading vehicle of the host vehicle S1 at a time before the current time is not the leading vehicle at the current time. Then, the speed control unit 323 re-measures the gentle brake time determined by the determination unit 322 from the current time to extend the gentle brake time. By operating in this way, the time for re-determining whether the change of the leading vehicle is a misjudgment can be provided by extending the gentle brake time.

[0097] When the leading vehicle of the host vehicle S1 changes from a state where the leading vehicle exists to a state where the leading vehicle does not exist, the speed control unit 323 ends the deceleration of the host vehicle S1 and accelerates the host vehicle S1. For example, when the acquisition unit 321 acquires other vehicle information indicating that another vehicle S2 does not exist while the host vehicle S1 is being decelerated, the speed control unit 323 accelerates the host vehicle S1 after ending the deceleration of the host vehicle S1. By operating in this way, when there is no leading vehicle for the host vehicle S1, the host vehicle S1 can be quickly accelerated based on the upper limit value of the vehicle speed set by the driver.

[0098] When there is a preceding vehicle during the acceleration of the host vehicle S1, the speed control unit 323 determines the acceleration of the host vehicle S1 based on the longitudinal distance and relative speed between the preceding vehicle and the host vehicle S1, and accelerates the host vehicle S1. On the other hand, when there is no preceding vehicle during the acceleration of the host vehicle S1, the speed control unit 323 determines the acceleration and vehicle speed based on the upper limit value of the vehicle speed set by the driver, and accelerates the host vehicle S1. Therefore, when there is a preceding vehicle, the speed control unit 323 accelerates the host vehicle S1 under the influence of the preceding vehicle, but when there is no preceding vehicle, the host vehicle S1 can be accelerated without being affected by other surrounding vehicles, so the acceleration can be increased.

[0099] Therefore, for example, when the speed control unit 323 finishes decelerating the host vehicle S1, the acquisition unit 321 specifies whether it has acquired other vehicle information indicating the absence of the other vehicle S2 or other vehicle information indicating the presence of the other vehicle S2. Then, when the speed control unit 323 specifies based on the other vehicle information that the other vehicle S2 does not exist, the acceleration after finishing decelerating is made larger than when it is specified based on the other vehicle information that the other vehicle S2 exists. By operating in this way, the speed control unit 323 can accelerate the host vehicle S1 according to the state around the host vehicle S1, so it is possible to suppress giving the driver a sense of discomfort.

[0100] <Processing sequence in the speed control device 30> FIGS. 12, 13, 14, and 15 are diagrams showing examples of processing sequences in the speed control device 30. FIG. 12 is a processing sequence showing an operation of specifying a preceding vehicle of the host vehicle S1 (preceding vehicle specifying process). FIG. 13 is a processing sequence showing an operation of waiting for deceleration of the host vehicle S1 (deceleration waiting process). FIG. 14 is a processing sequence showing an operation of decelerating the host vehicle S1 (deceleration process). FIG. 15 is a processing sequence showing an operation of accelerating the host vehicle S1 (return process).

[0101] The deceleration standby process shown in FIG. 13 is a sub-process of the preceding vehicle identification process shown in FIG. 12 and corresponds to the process of S17 shown in FIG. 12. The return process shown in FIG. 15 is a sub-process of the deceleration process shown in FIG. 14 and corresponds to the process of S32 shown in FIG. 14. As an example, the preceding vehicle identification process shown in FIG. 12 is repeated at a predetermined first cycle (for example, a fixed value less than 1 second), and the deceleration process shown in FIG. 14 is repeated at a predetermined second cycle longer than the predetermined first cycle.

[0102] First, the preceding vehicle identification process will be described with reference to FIG. 12. The acquisition unit 321 acquires the longitudinal distance and the first lateral distance between the host vehicle S1 and the other vehicle S2, the other vehicle information, and the vehicle ID from the first measurement device 11 (RADAR or LiDAR) (S10). The acquisition unit 321 acquires the second lateral distance from the second measurement device 12 (camera) (S11). The acquisition unit 321 acquires the vehicle speed of the host vehicle S1 from the vehicle speed sensor 14 (S12).

[0103] The speed control unit 323 determines whether there is an other vehicle S2 in front of the traveling direction of the host vehicle S1 by referring to the other vehicle information (S13). When there is no other vehicle S2 (NO in S13), the speed control device 30 ends the preceding vehicle identification process and ends the deceleration if the host vehicle S1 is decelerating. When there is an other vehicle S2 (YES in S13), the speed control unit 323 determines whether the vehicle speed of the host vehicle S1 acquired by the acquisition unit 321 is equal to or higher than the third threshold value (S14). When the vehicle speed is less than the third threshold value (NO in S14), the speed control unit 323 outputs the deceleration process parameter determined in the deceleration standby process shown in FIG. 13 to the deceleration process sequence shown in FIG. 14 (S18) and ends the preceding vehicle identification process. The details of the deceleration process parameter will be described later.

[0104] When the vehicle speed is equal to or higher than the third threshold (YES in S14), the determination unit 322 calculates a relative speed, which is a subtraction value obtained by subtracting the vehicle speed of the host vehicle S1 from the vehicle speed of the other vehicle S2, based on a plurality of longitudinal distances acquired by the acquisition unit 321 at a plurality of times including the first time (S15). When the relative speed is equal to or higher than 0 (NO in S16), the speed control device 30 ends the preceding vehicle identification process. When the relative speed is less than 0 (YES in S16), the speed control device 30 executes a deceleration standby process shown in FIG. 13 (S17).

[0105] Here, the deceleration standby process will be described with reference to FIG. 13. The speed control unit 323 acquires the first vehicle ID at a predetermined time (for example, the current time) and the second vehicle ID before a predetermined first period from the predetermined time. When the first vehicle ID and the second vehicle ID are the same, the speed control unit 323 determines that the other vehicle S2 traveling ahead in the traveling direction of the host vehicle S1 is the same at the current time and the time before the predetermined first period. On the other hand, when the first vehicle ID and the second vehicle ID are different, the speed control unit 323 determines that the other vehicle S2 traveling ahead in the traveling direction of the host vehicle S1 is different at the current time and the time before the predetermined first period.

[0106] When the other vehicle S2 at the current time is different from the other vehicle S2 at the time before the first period (YES in S20), the speed control unit 323 initializes the standby elapsed time that has elapsed at the current time among the standby times determined by the determination unit 322 (S21). On the other hand, when the other vehicle S2 at the current time is the same as the other vehicle S2 at the time before the first period (NO in S20), the speed control unit 323 does not initialize the standby elapsed time. Subsequently, the speed control unit 323 calculates an addition value obtained by adding the cycle time corresponding to the first period to the standby elapsed time (S22). The determination unit 322 refers to the standby time map stored in the storage unit 31 to determine the standby time corresponding to the relative speed calculated in S15 shown in FIG. 12 and the longitudinal distance acquired in S10 shown in FIG. 12 (S23).

[0107] If the added value calculated in S22 is less than the waiting time determined in S23 (NO in S24), the speed control unit 323 determines whether the host vehicle S1 is "following a preceding vehicle" (S28). "Following a preceding vehicle" means that the speed control device 30 identifies a preceding vehicle traveling in the same lane as the host vehicle S1 in front of the traveling direction of the host vehicle S1, and based on the longitudinal distance and relative speed between the host vehicle S1 and the preceding vehicle, the host vehicle S1 travels at a constant speed or accelerates or decelerates.

[0108] If it is "following a preceding vehicle" (YES in S28), the speed control unit 323 determines the relative speed, longitudinal distance, and the difference between the first lateral distance and the second lateral distance between the host vehicle S1 and the other vehicle S2 at a time before a predetermined first period from the current time as deceleration processing parameters (S29), and ends the deceleration waiting process. On the other hand, if it is not "following a preceding vehicle" (NO in S28), the speed control unit 323 ends the deceleration waiting process and the preceding vehicle identification process without determining the deceleration processing parameters.

[0109] If the added value calculated in S22 is greater than or equal to the waiting time determined in S23 (YES in S24), the speed control unit 323 determines whether the host vehicle S1 is not "following a preceding vehicle" (S25). If it is "following a preceding vehicle" (NO in S25), the speed control unit 323 determines the relative speed, longitudinal distance, and the difference between the first lateral distance and the second lateral distance between the host vehicle S1 and the other vehicle S2 at the current time as deceleration processing parameters (S27), and ends the deceleration waiting process. If it is not "following a preceding vehicle" (YES in S25), the speed control unit 323 determines whether the difference between the first lateral distance and the second lateral distance is less than a second threshold value (S26).

[0110] When the difference between the first lateral distance and the second lateral distance is less than the second threshold value (YES in S26), the speed control unit 323 determines the relative speed, longitudinal distance, and the difference between the first lateral distance and the second lateral distance between the host vehicle S1 and the other vehicle S2 at the current time as deceleration processing parameters (S27), and ends the deceleration standby process. When the difference between the first lateral distance and the second lateral distance is greater than or equal to the second threshold value (NO in S26), the speed control unit 323 ends the deceleration standby process and the preceding vehicle identification process without determining the deceleration processing parameters. Returning to FIG. 12, the speed control unit 323 outputs the deceleration processing parameters determined in the deceleration standby process shown in FIG. 13 to the deceleration processing sequence shown in FIG. 14 (S18), and ends the preceding vehicle identification process.

[0111] Next, the deceleration process will be described with reference to FIG. 14. The speed control unit 323 acquires the deceleration processing parameters, other vehicle information, vehicle ID, and the vehicle speed of the host vehicle S1 output by the preceding vehicle identification process sequence in S18 shown in FIG. 12 (S30). The speed control unit 323 determines whether there is an other vehicle S2 in front of the traveling direction of the host vehicle S1 by referring to the other vehicle information (S31). When there is no other vehicle S2 (NO in S31), the speed control device 30 executes the return process shown in FIG. 15 (S32) and ends the deceleration process.

[0112] Here, the return process will be described with reference to FIG. 15. The speed control unit 323 relaxes the deceleration of the host vehicle S1 (S50). When the deceleration has not reached 0 (NO in S51), the speed control unit 323 repeats the process of step S50. When the deceleration has reached 0 (YES in S51), the speed control unit 323 determines the acceleration for returning to the predetermined vehicle speed (S52), and accelerates the host vehicle S1 with the acceleration (S53). The predetermined vehicle speed is, for example, the vehicle speed of the host vehicle S1 at the first time. When the predetermined vehicle speed has not been reached (NO in S54), the speed control unit 323 repeats the process of step S53. When the predetermined vehicle speed has been reached (YES in S54), the speed control unit 323 ends the return process.

[0113] Returning to FIG. 14, when there is another vehicle S2 (YES in S31), the speed control unit 323 determines whether the vehicle speed of the host vehicle S1 is equal to or higher than the first threshold value (S33). When the vehicle speed of the host vehicle S1 is less than the first threshold value (NO in S33), the speed control unit 323 refers to the normal brake change amount map stored in the storage unit 31 to determine the change amount of the normal brake per unit time corresponding to the relative speed and the longitudinal distance. Then, the speed control unit 323 determines the normal brake (third deceleration) at the current time based on the normal brake (third deceleration) at a time before a predetermined second period from the current time and the determined change amount of the normal brake, decelerates the host vehicle S1 (S41), and ends the deceleration process.

[0114] When the vehicle speed of the host vehicle S1 is equal to or higher than the first threshold value (YES in S33), the speed control unit 323 determines whether the other vehicle S2 at the current time is the same as the other vehicle S2 at a time before a predetermined second period from the current time (S34). When the other vehicle S2 at the current time is different from the other vehicle S2 at the time before the second period (NO in S34), the speed control unit 323 initializes the elapsed soft brake time at the current time among the soft brake times determined by the determination unit 322 (S36). When the other vehicle S2 at the current time is the same as the other vehicle S2 at the time before the second period (YES in S34), the speed control unit 323 determines whether the difference between the first lateral distance and the second lateral distance is equal to or greater than the second threshold value (S35).

[0115] When the difference between the first lateral distance and the second lateral distance is equal to or greater than the second threshold value (YES in S35), the speed control unit 323 initializes the elapsed soft brake time at the current time (S36) and adds the cycle time corresponding to the second period to the soft brake standby time (S37). On the other hand, when the difference between the first lateral distance and the second lateral distance is less than the second threshold value (NO in S35), the speed control unit 323 adds the cycle time corresponding to the second period to the soft brake standby time without initializing the elapsed soft brake time (S37).

[0116] The determination unit 322 determines a creep braking time corresponding to the relative speed and the longitudinal distance, for example, by referring to the creep braking time map stored in the storage unit 31 (S38). When the added value calculated in S37 is equal to or greater than the creep braking time determined in S38 (NO in S39), the speed control unit 323 decelerates the host vehicle S1 with a normal brake (third deceleration) (S41), and ends the deceleration process.

[0117] When the added value calculated in S37 is less than the creep braking time determined in S38 (YES in S39), the speed control unit 323 determines the amount of change in creep braking per unit time corresponding to the relative speed and the longitudinal distance by referring to the creep braking change amount map stored in the storage unit 31. The speed control unit 323 may calculate the amount of change in creep braking per unit time so that the host vehicle S1 reaches a predetermined longitudinal distance even if it decelerates with a normal brake based on the relative speed and the longitudinal distance. Then, the speed control unit 323 determines the creep braking (second deceleration) at the current time based on the creep braking (second deceleration) at a time before a predetermined second period from the current time and the determined amount of change in creep braking, decelerates the host vehicle S1 (S40), and ends the deceleration process.

[0118] <Modification example> In the above description, the operation of the determination unit 322 calculating the subtracted value obtained by subtracting the vehicle speed of the host vehicle S1 from the vehicle speed of the other vehicle S2 as the relative speed is exemplified, but it is not limited to this. The determination unit 322 may calculate the subtracted value obtained by subtracting the vehicle speed of the other vehicle S2 from the vehicle speed of the host vehicle S1 as the relative speed. In this case, the speed control unit 323 controls the speed of the host vehicle S1 so as to decelerate the host vehicle S1 if the relative speed is greater than 0, and accelerate the host vehicle S1 if the relative speed is less than 0.

[0119] <Effect of the speed control device 30> As described above, the speed control device 30 includes an acquisition unit 321 that acquires, based on the reflected wave of light waves or radio waves emitted to the other vehicle S2, the longitudinal distance between the position of the other vehicle S2 traveling ahead in the traveling direction of the host vehicle S1 and the position of the host vehicle S1 in the longitudinal direction of the host vehicle S1 from a first measuring device 11 that specifies the position of the other vehicle S2; a determination unit 322 that determines a first deceleration time for decelerating the host vehicle S1 at a second deceleration that is smaller than a first deceleration for making the relative speed of the host vehicle S1 with respect to the other vehicle S2 zero, based on the relative speed and the longitudinal distance between the other vehicle S2 and the host vehicle S1 at a first time; and a speed control unit 323 that decelerates the host vehicle S1 at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerates the host vehicle S1 at a third deceleration that is greater than the first deceleration at times after the second time.

[0120] With the speed control device 30 configured in this way, even if the speed control device 30 erroneously determines that the other vehicle S2 is a preceding vehicle, it can re-determine whether the other vehicle S2 is a preceding vehicle while suppressing the deceleration of the host vehicle S1 during the first deceleration time for decelerating at the second deceleration. Then, when it is determined in the re-determination that the other vehicle S2 is a preceding vehicle, the speed control device 30 can decelerate at the third deceleration. As a result, the speed control device 30 can improve the accuracy of determining whether the other vehicle S2 is a preceding vehicle and can decelerate so as not to contact the preceding vehicle.

[0121] Furthermore, when it is determined in the re-determination that the other vehicle S2 is not a preceding vehicle, the speed control device 30 can end the deceleration of the host vehicle S1 in a state where the change amount of the vehicle speed is small during the first deceleration time and accelerate the host vehicle S1. As a result, since the change amount of the vehicle speed until the deceleration of the host vehicle S1 ends can be suppressed, the vehicle speed can be quickly restored to the vehicle speed before the host vehicle S1 is decelerated, or the sense of discomfort given to the driver of the host vehicle S1 can be reduced.

[0122] As described above, the present invention has been described using embodiments. However, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist. For example, all or part of the device can be configured by functionally or physically dispersing and integrating it in any unit. Also, new embodiments resulting from any combination of a plurality of embodiments are included in the embodiments of the present invention. The effects of the new embodiments resulting from the combination have the effects of the original embodiments combined.

Explanation of Reference Numerals

[0123] 10 Measurement system 11 First measurement device 12 Second measurement device 13 Measurement control device 14 Vehicle speed sensor 21 Drive source 22 Braking device 30 Speed control device 31 Storage unit 32 Control unit 321 Acquisition unit 322 Determination unit 323 Speed control unit

Claims

1. An acquisition unit that acquires a longitudinal distance, which is a distance between the position of another vehicle traveling ahead in the traveling direction of the host vehicle and the position of the host vehicle in the longitudinal direction of the host vehicle, from a first measuring device that identifies the position of the other vehicle based on a reflected wave of light waves or radio waves emitted to the other vehicle; A determination unit that determines a first deceleration time for decelerating the host vehicle at a second deceleration that is smaller than a first deceleration for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed between the other vehicle and the host vehicle and the longitudinal distance at a first time; A speed control unit that decelerates the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerates the host vehicle at a third deceleration that is greater than the first deceleration at times after the second time; comprising The acquisition unit acquires the vehicle speed of the host vehicle; When the vehicle speed is equal to or higher than a first threshold value, the speed control unit decelerates the host vehicle at the second deceleration from the first time to the first deceleration time, and when the vehicle speed is lower than the first threshold value, the speed control unit decelerates the host vehicle at the third deceleration at times after the first time. A speed control device.

2. An acquisition unit that acquires a longitudinal distance, which is a distance between the position of another vehicle traveling ahead in the traveling direction of the host vehicle and the position of the host vehicle in the longitudinal direction of the host vehicle, from a first measuring device that identifies the position of the other vehicle based on a reflected wave of light waves or radio waves emitted to the other vehicle; A determination unit that determines a first deceleration time for decelerating the host vehicle at a second deceleration that is smaller than a first deceleration for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed between the other vehicle and the host vehicle and the longitudinal distance at a first time; A speed control unit that decelerates the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerates the host vehicle at a third deceleration that is greater than the first deceleration at times after the second time; comprising The acquisition unit acquires a first lateral distance, which is a distance between the position of the other vehicle and the position of the host vehicle in the width direction of the host vehicle, measured by the first measuring device, and a second lateral distance, which is different from the first lateral distance, measured by a second measuring device that identifies the position of the other vehicle based on an imaging image generated by imaging the front in the traveling direction of the host vehicle. When the speed control unit detects that the difference between the first lateral distance and the second lateral distance is equal to or greater than a second threshold value, the speed control unit decelerates the host vehicle at the second deceleration in the first deceleration time from the detected time. Speed control device.

3. The acquisition unit acquires vehicle identification information for identifying the other vehicle from the first measurement device, in association with the longitudinal distance or the first lateral distance. When the vehicle identification information acquired at a time before a predetermined time is different from the vehicle identification information acquired at the predetermined time, the speed control unit decelerates the host vehicle at the second deceleration in the first deceleration time from the predetermined time. The speed control device according to claim 2.

4. An acquisition unit that acquires a longitudinal distance, which is a distance between the position of the other vehicle traveling ahead in the traveling direction of the host vehicle and the position of the host vehicle in the longitudinal direction of the host vehicle, from a first measurement device that specifies the position of the other vehicle based on a reflected wave of a light wave or a radio wave emitted to the other vehicle; A determination unit that determines a first deceleration time for decelerating at a second deceleration that is smaller than a first deceleration for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at a first time; A speed control unit that decelerates the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed from the first time, and decelerates the host vehicle at a third deceleration that is greater than the first deceleration at a time after the second time; comprising The determination unit determines a first target deceleration that is the upper limit value of the second deceleration, a second target deceleration that is the upper limit value of the third deceleration, and a second deceleration time for decelerating at the third deceleration, based on the relative speed and the longitudinal distance at the first time. The speed control unit decelerates the host vehicle so that the second deceleration reaches the first target deceleration in the first deceleration time, and decelerates the host vehicle so that the third deceleration reaches the second target deceleration in the second deceleration time. Speed control device.

5. The speed control device further includes a storage unit that stores a first change amount map indicating a change amount per unit time of the second deceleration corresponding to the relative speed and the longitudinal distance, and a second change amount map indicating a change amount per unit time of the third deceleration corresponding to the relative speed and the longitudinal distance. The speed control unit decelerates the host vehicle at the second deceleration determined by referring to the first change amount map during the first deceleration time, and decelerates the host vehicle at the third deceleration determined by referring to the second change amount map during the second deceleration time. The speed control device according to claim 4.

6. An acquisition unit that acquires a longitudinal distance, which is a distance between the position of another vehicle traveling ahead of the host vehicle in the longitudinal direction of the host vehicle and the position of the host vehicle, from a first measuring device that specifies the position of the other vehicle based on a reflected wave of light waves or radio waves emitted to the other vehicle; A determination unit that determines a first deceleration time for decelerating the host vehicle at a second deceleration that is smaller than a first deceleration for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at a first time; A speed control unit that decelerates the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed from the first time, and decelerates the host vehicle at a third deceleration that is greater than the first deceleration at a time after the second time; comprising The acquisition unit acquires the vehicle speed of the host vehicle; The determination unit determines a waiting time from the first time until a time when deceleration at the second deceleration starts, based on the relative speed and the longitudinal distance at the first time; When the vehicle speed is equal to or higher than a third threshold value, the speed control unit decelerates the host vehicle at the second deceleration during the first deceleration time from the time when the waiting time has elapsed. Speed control device.

7. An acquisition unit that acquires a longitudinal distance, which is a distance between the position of another vehicle traveling ahead of the host vehicle in the longitudinal direction of the host vehicle and the position of the host vehicle, from a first measuring device that specifies the position of the other vehicle based on a reflected wave of light waves or radio waves emitted to the other vehicle; A determination unit that determines a first deceleration time for decelerating the host vehicle at a second deceleration that is smaller than a first deceleration for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at a first time; A speed control unit that decelerates the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed from the first time, and decelerates the host vehicle at a third deceleration that is greater than the first deceleration at a time after the second time; comprising The acquisition unit acquires, from the first measurement device, vehicle identification information for identifying the other vehicle, in association with the longitudinal distance or a first lateral distance between the position of the other vehicle and the position of the host vehicle in the width direction of the host vehicle. The determination unit determines a waiting time from the first time until the time to start deceleration at the second deceleration rate, based on the relative speed and the longitudinal distance at the first time. If the vehicle identification information acquired at a predetermined time is different from the vehicle identification information acquired at a time before the predetermined time during the waiting time, the speed control unit starts decelerating the host vehicle at the second deceleration rate at the time when the waiting time has elapsed from the predetermined time, and decelerates the host vehicle at the second deceleration rate during the first deceleration time from the time when the waiting time has elapsed. Speed control device.

8. An acquisition unit that acquires, from a first measurement device that specifies the position of the other vehicle based on a reflected wave of light waves or radio waves emitted to the other vehicle, a longitudinal distance that is a distance between the position of the other vehicle traveling ahead of the host vehicle in the traveling direction of the host vehicle and the position of the host vehicle in the longitudinal direction of the host vehicle, in association with vehicle identification information for identifying the other vehicle; A determination unit that determines a first deceleration time for decelerating at a second deceleration rate that is smaller than a first deceleration rate for setting the relative speed of the host vehicle with respect to the other vehicle to zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at a first time; A speed control unit that decelerates the host vehicle at the second deceleration rate from the first time until a second time when the first deceleration time has elapsed, and decelerates the host vehicle at a third deceleration rate that is larger than the first deceleration rate at a time after the second time; comprising The acquisition unit acquires, from the first measurement device, vehicle identification information for identifying the other vehicle, in association with the longitudinal distance or a first lateral distance between the position of the other vehicle and the position of the host vehicle in the width direction of the host vehicle. The determination unit determines a waiting time from the first time until the time to start deceleration at the second deceleration rate, based on the relative speed and the longitudinal distance at the first time. If the first vehicle identification information at a predetermined time is different from the second vehicle identification information at a time before the predetermined time during the waiting time or the first deceleration time, the speed control unit decelerates the host vehicle at the second deceleration rate based on the relative speed and the longitudinal distance associated with the first vehicle identification information, during the first deceleration time from the time when the waiting time has elapsed. Speed control device.

9. An acquisition unit that acquires, based on a reflected wave of light waves or radio waves emitted to the other vehicle, a longitudinal distance, which is a distance between the position of the other vehicle traveling ahead of the host vehicle in the longitudinal direction of the host vehicle and the position of the host vehicle, from a first measuring device that specifies the position of the other vehicle; A determination unit that determines a first deceleration time for decelerating the host vehicle at a second deceleration that is smaller than a first deceleration for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at a first time; A speed control unit that decelerates the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerates the host vehicle at a third deceleration that is greater than the first deceleration at a time after the second time; comprising: The acquisition unit acquires a first lateral distance, which is a distance between the position of the other vehicle and the position of the host vehicle in the width direction of the host vehicle, measured by the first measuring device, and a second lateral distance, which is different from the first lateral distance, measured by a second measuring device that specifies the position of the other vehicle based on an imaging image generated by imaging the front of the traveling direction of the host vehicle; The determination unit determines a waiting time from the first time until a time when deceleration at the second deceleration starts, based on the relative speed and the longitudinal distance at the first time; The speed control unit does not decelerate the host vehicle when the difference between the first lateral distance and the second lateral distance is equal to or greater than a second threshold value after the waiting time has elapsed; Speed control device.

10. The acquisition unit acquires other vehicle information indicating the presence or absence of other vehicles traveling in a region measurable by the first measuring device ahead of the traveling direction of the host vehicle; When the acquisition unit acquires the other vehicle information indicating that there is no other vehicle while the host vehicle is being decelerated, the speed control unit accelerates the host vehicle after terminating the deceleration of the host vehicle; The speed control device according to any one of claims 1 to 9.

11. An acquisition unit that acquires, based on a reflected wave of light waves or radio waves emitted to the other vehicle, a longitudinal distance, which is a distance between the position of the other vehicle traveling ahead of the host vehicle in the longitudinal direction of the host vehicle and the position of the host vehicle, from a first measuring device that specifies the position of the other vehicle; A determination unit that determines a first deceleration time for decelerating at a second deceleration smaller than a first deceleration that makes the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at a first time; A speed control unit that decelerates the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerates the host vehicle at a third deceleration greater than the first deceleration at times after the second time; comprising; The acquisition unit acquires other vehicle information indicating the presence or absence of other vehicles traveling in a region measurable by the first measurement device in front of the traveling direction of the host vehicle; When the acquisition unit acquires the other vehicle information indicating that no other vehicle exists when the speed control unit ends the deceleration of the host vehicle, the speed control unit increases the acceleration after ending the deceleration more than when the acquisition unit acquires the other vehicle information indicating the presence of the other vehicle; A speed control device.

12. Executed by a processor, An acquisition step of acquiring, from a first measurement device that identifies the position of an other vehicle based on a reflected wave of light waves or radio waves emitted to the other vehicle, a longitudinal distance that is the inter-vehicle distance between the position of the other vehicle traveling in front of the traveling direction of the host vehicle and the position of the host vehicle in the longitudinal direction of the host vehicle; A determination step of determining a first deceleration time for decelerating at a second deceleration smaller than a first deceleration that makes the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at a first time; A speed control step of decelerating the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerating the host vehicle at a third deceleration greater than the first deceleration at times after the second time; comprising; In the acquisition step, the vehicle speed of the host vehicle is acquired; In the speed control step, when the vehicle speed is equal to or higher than a first threshold value, the host vehicle is decelerated at the second deceleration from the first time to the first deceleration time, and when the vehicle speed is lower than the first threshold value, the host vehicle is decelerated at the third deceleration at a time after the first time; A speed control method.

13. Executed by a processor, An acquisition step of acquiring, from a first measuring device that specifies the position of the other vehicle based on a reflected wave of light waves or radio waves emitted to the other vehicle, a longitudinal distance that is the inter-vehicle distance between the position of the other vehicle traveling ahead in the traveling direction of the host vehicle and the position of the host vehicle in the longitudinal direction of the host vehicle; A determination step of determining a first deceleration time for decelerating at a second deceleration that is smaller than a first deceleration for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed between the other vehicle and the host vehicle and the longitudinal distance at a first time; A speed control step of decelerating the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerating the host vehicle at a third deceleration that is greater than the first deceleration at times after the second time; comprising; In the acquisition step, a first lateral distance between the position of the other vehicle and the position of the host vehicle in the width direction of the host vehicle measured by the first measuring device, and a second lateral distance different from the first lateral distance measured by a second measuring device that specifies the position of the other vehicle based on a captured image generated by imaging the front in the traveling direction of the host vehicle are acquired; In the speed control step, when it is detected that the difference between the first lateral distance and the second lateral distance is equal to or greater than a second threshold value, the host vehicle is decelerated at the second deceleration from the detected time to the first deceleration time. A speed control method.

14. Executed by a processor, An acquisition step of acquiring, from a first measuring device that specifies the position of the other vehicle based on a reflected wave of light waves or radio waves emitted to the other vehicle, a longitudinal distance that is the inter-vehicle distance between the position of the other vehicle traveling ahead in the traveling direction of the host vehicle and the position of the host vehicle in the longitudinal direction of the host vehicle; A determination step of determining a first deceleration time for decelerating at a second deceleration that is smaller than a first deceleration for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed between the other vehicle and the host vehicle and the longitudinal distance at a first time; A speed control step of decelerating the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerating the host vehicle at a third deceleration that is greater than the first deceleration at times after the second time; comprising; In the determination step, based on the relative speed and the longitudinal distance at the first time, a first target deceleration which is the upper limit value of the second deceleration, a second target deceleration which is the upper limit value of the third deceleration, and a second deceleration time for decelerating at the third deceleration are determined. In the speed control step, the host vehicle is decelerated such that the second deceleration reaches the first target deceleration at the first deceleration time, and the host vehicle is decelerated such that the third deceleration reaches the second target deceleration at the second deceleration time. Speed control method.

15. Executed by a processor An acquisition step of acquiring, from a first measuring device that specifies the position of another vehicle traveling ahead in the traveling direction of the host vehicle in the longitudinal direction of the host vehicle, a longitudinal distance which is the inter-vehicle distance between the position of the other vehicle and the position of the host vehicle, based on a reflected wave of a light wave or a radio wave emitted to the other vehicle. A determination step of determining a first deceleration time for decelerating at a second deceleration that is smaller than a first deceleration for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at a first time. A speed control step of decelerating the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerating the host vehicle at a third deceleration that is greater than the first deceleration at a time after the second time. having In the acquisition step, the vehicle speed of the host vehicle is acquired. In the determination step, based on the relative speed and the longitudinal distance at the first time, a waiting time from the first time until the time to start decelerating at the second deceleration is determined. In the speed control step, when the vehicle speed is equal to or higher than a third threshold value, the host vehicle is decelerated at the second deceleration from the time when the waiting time has elapsed until the first deceleration time. Speed control method.

16. Executed by a processor An acquisition step of acquiring, from a first measuring device that specifies the position of another vehicle traveling ahead in the traveling direction of the host vehicle in the longitudinal direction of the host vehicle, a longitudinal distance which is the inter-vehicle distance between the position of the other vehicle and the position of the host vehicle, based on a reflected wave of a light wave or a radio wave emitted to the other vehicle. A determination step of determining a first deceleration time for decelerating at a second deceleration that is smaller than a first deceleration for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at a first time. From the first time until the second time when the first deceleration time has elapsed, the host vehicle is decelerated at the second deceleration, and at times after the second time, the host vehicle is decelerated at a third deceleration greater than the first deceleration; a speed control step having In the acquisition step, vehicle identification information for identifying the other vehicle is acquired from the first measurement device in association with the longitudinal distance or a first lateral distance between the position of the other vehicle and the position of the host vehicle in the width direction of the host vehicle. In the determination step, based on the relative speed and the longitudinal distance at the first time, a waiting time from the first time until the time to start deceleration at the second deceleration is determined. In the speed control step, during the waiting time, when the vehicle identification information acquired at a predetermined time is different from the vehicle identification information acquired at a time before the predetermined time, the deceleration of the host vehicle at the second deceleration is started at the time when the waiting time has elapsed from the predetermined time, and from the time when the waiting time has elapsed until the first deceleration time, the host vehicle is decelerated at the second deceleration. A speed control method.

17. Executed by a processor An acquisition step of acquiring, from a first measurement device that specifies the position of an other vehicle traveling ahead of the host vehicle in the traveling direction of the host vehicle in the longitudinal direction of the host vehicle, a longitudinal distance that is the inter-vehicle distance between the position of the other vehicle and the position of the host vehicle, based on a reflected wave of light waves or radio waves emitted to the other vehicle; A determination step of determining a first deceleration time for decelerating at a second deceleration that is smaller than a first deceleration for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at the first time; From the first time until the second time when the first deceleration time has elapsed, the host vehicle is decelerated at the second deceleration, and at times after the second time, the host vehicle is decelerated at a third deceleration greater than the first deceleration; a speed control step having In the acquisition step, vehicle identification information for identifying the other vehicle is acquired from the first measurement device in association with the longitudinal distance or a first lateral distance between the position of the other vehicle and the position of the host vehicle in the width direction of the host vehicle. In the determination step, based on the relative speed and the longitudinal distance at the first time, a waiting time from the first time until the time to start deceleration at the second deceleration is determined. In the speed control step, in the standby time or the first deceleration time, when the first vehicle identification information at a predetermined time is different from the second vehicle identification information at a time before the predetermined time, from the time when the standby time has elapsed to the first deceleration time, the host vehicle is decelerated at the second deceleration rate based on the relative speed and the longitudinal distance associated with the first vehicle identification information. Speed control method.

18. Executed by a processor An acquisition step of acquiring, from a first measurement device that identifies the position of another vehicle traveling ahead of the host vehicle in the traveling direction of the host vehicle in the longitudinal direction of the host vehicle, the longitudinal distance that is the inter-vehicle distance between the position of the other vehicle and the position of the host vehicle, based on the reflected wave of light waves or radio waves emitted to the other vehicle; A determination step of determining a first deceleration time for decelerating the host vehicle at a second deceleration rate that is smaller than a first deceleration rate for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at a first time; A speed control step of decelerating the host vehicle at the second deceleration rate from the first time until a second time when the first deceleration time has elapsed from the first time, and decelerating the host vehicle at a third deceleration rate that is greater than the first deceleration rate at a time after the second time; comprising In the acquisition step, based on the first lateral distance between the position of the other vehicle and the position of the host vehicle in the width direction of the host vehicle measured by the first measurement device, and a second lateral distance different from the first lateral distance measured by a second measurement device that identifies the position of the other vehicle based on an imaging image generated by imaging the front in the traveling direction of the host vehicle, the host vehicle acquires the second lateral distance; In the determination step, based on the relative speed and the longitudinal distance at the first time, a standby time from the first time until the time when deceleration at the second deceleration rate starts is determined; In the speed control step, after the standby time has elapsed, when the difference between the first lateral distance and the second lateral distance is greater than or equal to a second threshold value, the host vehicle is not decelerated. Speed control method.

19. Executed by a processor An acquisition step of acquiring, from a first measurement device that identifies the position of another vehicle traveling ahead of the host vehicle in the traveling direction of the host vehicle in the longitudinal direction of the host vehicle, the longitudinal distance that is the inter-vehicle distance between the position of the other vehicle and the position of the host vehicle, based on the reflected wave of light waves or radio waves emitted to the other vehicle; A determination step of determining a first deceleration time for decelerating at a second deceleration smaller than a first deceleration that makes the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at a first time; A speed control step of decelerating the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerating the host vehicle at a third deceleration greater than the first deceleration at a time after the second time; comprising: In the acquisition step, other vehicle information indicating the presence or absence of an other vehicle traveling in an area measurable by the first measuring device is acquired in front of the traveling direction of the host vehicle; In the speed control step, when ending the deceleration of the host vehicle, the acceleration after ending the deceleration is made greater when the other vehicle information indicating the absence of the other vehicle is acquired in the acquisition step than when the other vehicle information indicating the presence of the other vehicle is not acquired in the acquisition step; A speed control method.

20. On a processor, a step of obtaining, from a first measuring device that identifies the position of an other vehicle based on a reflected wave of a light wave or a radio wave emitted to the other vehicle, a longitudinal distance that is the distance between the position of the other vehicle traveling in front of the traveling direction of the host vehicle and the position of the host vehicle in the longitudinal direction of the host vehicle; a step of determining a first deceleration time for decelerating at a second deceleration smaller than a first deceleration that makes the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at a first time; a step of decelerating the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerating the host vehicle at a third deceleration greater than the first deceleration at a time after the second time; causing to execute, In the obtaining step, the vehicle speed of the host vehicle is obtained; In the decelerating step, when the vehicle speed is equal to or higher than a first threshold value, the host vehicle is decelerated at the second deceleration from the first time to the first deceleration time, and when the vehicle speed is lower than the first threshold value, the host vehicle is decelerated at the third deceleration at a time after the first time; A program.

21. On a processor, A step of obtaining a longitudinal distance, which is a distance between the position of another vehicle traveling ahead in the traveling direction of the host vehicle and the position of the host vehicle in the longitudinal direction of the host vehicle, from a first measuring device that specifies the position of the other vehicle based on a reflected wave of light waves or radio waves emitted to the other vehicle; A step of determining a first deceleration time for decelerating at a second deceleration smaller than a first deceleration that makes the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed between the other vehicle and the host vehicle and the longitudinal distance at a first time; A step of decelerating the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerating the host vehicle at a third deceleration greater than the first deceleration at a time after the second time; To execute; In the obtaining step, a first lateral distance between the position of the other vehicle and the position of the host vehicle in the width direction of the host vehicle measured by the first measuring device, and a second lateral distance different from the first lateral distance measured by a second measuring device that specifies the position of the other vehicle based on an imaging image generated by imaging the front in the traveling direction of the host vehicle are obtained; In the decelerating step, the host vehicle is decelerated at the second deceleration from the time when it is detected that the difference between the first lateral distance and the second lateral distance is equal to or greater than a second threshold value until the first deceleration time; Program.

22. To a processor, A step of obtaining a longitudinal distance, which is a distance between the position of another vehicle traveling ahead in the traveling direction of the host vehicle and the position of the host vehicle in the longitudinal direction of the host vehicle, from a first measuring device that specifies the position of the other vehicle based on a reflected wave of light waves or radio waves emitted to the other vehicle; A step of determining a first deceleration time for decelerating at a second deceleration smaller than a first deceleration that makes the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed between the other vehicle and the host vehicle and the longitudinal distance at a first time; A step of decelerating the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerating the host vehicle at a third deceleration greater than the first deceleration at a time after the second time; To execute; In the step of making the determination, based on the relative speed and the longitudinal distance at the first time, a first target deceleration which is the upper limit value of the second deceleration, a second target deceleration which is the upper limit value of the third deceleration, and a second deceleration time for decelerating at the third deceleration are determined. In the step of decelerating, the host vehicle is decelerated such that the second deceleration reaches the first target deceleration at the first deceleration time, and the host vehicle is decelerated such that the third deceleration reaches the second target deceleration at the second deceleration time. Program.

23. To a processor, a step of obtaining, from a first measuring device that identifies the position of another vehicle traveling ahead of the host vehicle in the traveling direction of the host vehicle in the longitudinal direction of the host vehicle, a longitudinal distance which is the inter-vehicle distance between the position of the other vehicle and the position of the host vehicle, based on a reflected wave of light waves or radio waves emitted to the other vehicle; a step of determining a first deceleration time for decelerating at a second deceleration which is smaller than a first deceleration for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at a first time; a step of decelerating the host vehicle at the second deceleration from the first time until a second time when the first deceleration time has elapsed, and decelerating the host vehicle at a third deceleration which is greater than the first deceleration at a time after the second time; to execute, in the step of obtaining, the vehicle speed of the host vehicle is obtained; in the step of making the determination, based on the relative speed and the longitudinal distance at the first time, a waiting time from the first time until a time when deceleration at the second deceleration starts is determined; in the step of decelerating, when the vehicle speed is equal to or higher than a third threshold value, the host vehicle is decelerated at the second deceleration from a time when the waiting time has elapsed until the first deceleration time. Program.

24. To a processor, a step of obtaining, from a first measuring device that identifies the position of another vehicle traveling ahead of the host vehicle in the traveling direction of the host vehicle in the longitudinal direction of the host vehicle, a longitudinal distance which is the inter-vehicle distance between the position of the other vehicle and the position of the host vehicle, based on a reflected wave of light waves or radio waves emitted to the other vehicle; a step of determining a first deceleration time for decelerating at a second deceleration which is smaller than a first deceleration for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at a first time; From the first time until the second time when the first deceleration time has elapsed, decelerate the host vehicle at the second deceleration rate, and at times after the second time, decelerate the host vehicle at a third deceleration rate that is greater than the first deceleration rate; Cause to execute; In the step of obtaining, obtain vehicle identification information for identifying the other vehicle from the first measuring device in association with the longitudinal distance or a first lateral distance between the position of the other vehicle and the position of the host vehicle in the width direction of the host vehicle; In the step of determining, determine a waiting time from the first time until the time to start deceleration at the second deceleration rate based on the relative speed and the longitudinal distance at the first time; In the step of decelerating, due to the vehicle identification information obtained at a predetermined time being different from the vehicle identification information obtained at a time before the predetermined time during the waiting time, start decelerating the host vehicle at the second deceleration rate at the time when the waiting time has elapsed from the predetermined time, and decelerate the host vehicle at the second deceleration rate during the first deceleration time from the time when the waiting time has elapsed; Program.

25. A processor, Obtain, from a first measuring device that specifies the position of the other vehicle based on a reflected wave of light waves or radio waves emitted to the other vehicle, a longitudinal distance that is the distance between the position of the other vehicle traveling ahead of the host vehicle in the longitudinal direction of the host vehicle and the position of the host vehicle; Determine a first deceleration time to decelerate at a second deceleration rate that is smaller than a first deceleration rate that makes the relative speed of the host vehicle with respect to the other vehicle zero based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at the first time; From the first time until the second time when the first deceleration time has elapsed, decelerate the host vehicle at the second deceleration rate, and at times after the second time, decelerate the host vehicle at a third deceleration rate that is greater than the first deceleration rate; Cause to execute; In the step of obtaining, obtain vehicle identification information for identifying the other vehicle from the first measuring device in association with the longitudinal distance or a first lateral distance between the position of the other vehicle and the position of the host vehicle in the width direction of the host vehicle; In the step of determining, determine a waiting time from the first time until the time to start deceleration at the second deceleration rate based on the relative speed and the longitudinal distance at the first time; In the step of decelerating, in the waiting time or the first deceleration time, when the first vehicle identification information at a predetermined time is different from the second vehicle identification information at a time before the predetermined time, from the time when the waiting time has elapsed to the first deceleration time, the host vehicle is decelerated at the second deceleration rate based on the relative speed and the longitudinal distance associated with the first vehicle identification information. Program.

26. The processor is caused to acquire, from a first measuring device that identifies the position of another vehicle traveling ahead of the host vehicle in the traveling direction of the host vehicle in the longitudinal direction of the host vehicle, the longitudinal distance that is the inter-vehicle distance between the position of the other vehicle and the position of the host vehicle, based on the reflected wave of the light wave or radio wave emitted to the other vehicle; determine a first deceleration time for decelerating the host vehicle at a second deceleration rate that is smaller than a first deceleration rate for making the relative speed of the host vehicle with respect to the other vehicle zero, based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at a first time; decelerate the host vehicle at the second deceleration rate from the first time until a second time when the first deceleration time has elapsed from the first time, and decelerate the host vehicle at a third deceleration rate that is greater than the first deceleration rate at a time after the second time; execute, in the step of acquiring, acquire a first lateral distance that is the lateral distance between the position of the other vehicle and the position of the host vehicle in the width direction of the host vehicle measured by the first measuring device, and a second lateral distance that is different from the first lateral distance and is measured by a second measuring device that identifies the position of the other vehicle based on a captured image generated by imaging the front in the traveling direction of the host vehicle; in the step of determining, determine a waiting time from the first time until the time when deceleration at the second deceleration rate starts, based on the relative speed and the longitudinal distance at the first time; in the step of decelerating, after the waiting time has elapsed, when the difference between the first lateral distance and the second lateral distance is equal to or greater than a second threshold value, do not decelerate the host vehicle. Program.

27. The processor is caused to acquire, from a first measuring device that identifies the position of another vehicle traveling ahead of the host vehicle in the traveling direction of the host vehicle in the longitudinal direction of the host vehicle, the longitudinal distance that is the inter-vehicle distance between the position of the other vehicle and the position of the host vehicle, based on the reflected wave of the light wave or radio wave emitted to the other vehicle; Based on the relative speed and the longitudinal distance between the other vehicle and the host vehicle at the first moment, determining a first deceleration time for decelerating at a second deceleration smaller than a first deceleration that makes the relative speed of the host vehicle with respect to the other vehicle zero; From the first moment until the second moment when the first deceleration time has elapsed, decelerating the host vehicle at the second deceleration, and at a time after the second moment, decelerating the host vehicle at a third deceleration greater than the first deceleration; causing the execution; In the obtaining step, obtaining other vehicle information indicating the presence or absence of other vehicles traveling in a region measurable by the first measuring device in front of the traveling direction of the host vehicle; In the decelerating step, when ending the deceleration of the host vehicle, the acceleration after ending the deceleration is made greater when the other vehicle information indicating the absence of the other vehicle is obtained in the obtaining step than when the other vehicle information indicating the presence of the other vehicle is not obtained in the obtaining step; Program.

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