DRIVING ASSISTANT FOR VEHICLES

Abstract

Driving assistant (2) for vehicles, which determines whether it is permissible or not for the own vehicle (C0) to enter an adjacent lane (Lrt) that is adjacent to a lane (Lr) in which the own vehicle (C0) is driving, and provides lane change assistance, wherein the driving assistant (2) for vehicles comprises: a proposed lane change segment placement unit (20) which, based on the relative speeds and relative positions of the own vehicle (C0) to a plurality of vehicles (C1 to C3) traveling parallel to it in the adjacent lane (Lrt), sets approach times (t1, t2 and t3) in which the own vehicle (C0) comes alongside each of the parallel vehicles (C1 to C3) and sets as a proposed lane change segment (Lp1, Lp3, Lp12, Lp23) a segment in front of or behind one of the parallel vehicles (C1 to C3) with which the own vehicle (C0) comes alongside in one of the shortest approach times (t1, t2 and t3); and a lane change determination unit (21) which, based on a relative speed calculated from the speed of movement of the proposed lane change section (Lp1, Lp3, Lp12, Lp23) and the speed of the own vehicle (C0), determines, when a section distance (Lk) of the proposed lane change section (Lp1, Lp3, Lp12, Lp23) is equal to or greater than a set value (Lth), whether or not it is permissible for the own vehicle (C0) to enter the proposed lane change section (Lp1, Lp3, Lp12, Lp23), wherein, in a case where the own vehicle (C0) is located between two parallel vehicles (C1 to C3), an average speed of the two parallel vehicles (C1 to C3) in front of or behind the own vehicle (C0) serves as the speed of movement of the proposed lane change section (Lp1, Lp3, Lp12, Lp23), and in a case where the own vehicle (C0) is not located between two parallel vehicles (C1 to C3), the speed of one of the parallel vehicles (C1 to C3) that is closest to the own vehicle (C0) serves as the speed of movement of the proposed lane change section (Lp1, Lp3, Lp12, Lp23).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from Japanese Patent Application No. 2015-137572, filed on July 9, 2015, the entire contents of which are hereby incorporated by reference. BACKGROUND

[0002] The invention relates to a driving assistant for vehicles which can assist a vehicle when changing lanes between adjacent lanes.

[0003] In recent years, various assistants for vehicles such as automobiles have been developed and put into practical use. Such assistants may be equipped with a camera or radar system and can detect a vehicle's driving environment to reduce the driver's workload. Such assistants can provide various driving assistance functions, one of which may be the ability to assist the driver's own vehicle in safely changing lanes.

[0004] For example, Japanese Unexamined Patent Application Publication No. JP 2009-294943 A discloses a technique that aims to assist safe lane changing. This technique includes determining a driving state of a vehicle in a target lane into which the host vehicle intends to enter; determining the presence or absence of a vehicle that intends to enter the target lane from outside a lane in which the host vehicle is traveling; and setting guidance information based on the vehicle in the target lane and the vehicle outside the target lane. SUMMARY

[0005] The lane change assistant disclosed in JP 2009-294943 A takes into account the presence of another vehicle attempting to enter the lane change target lane. On the other hand, this technology is not designed for driving conditions with multiple other vehicles in the lane change target lane, and therefore may not be able to support a quick and safe lane change in a case where the inter-vehicle distances between the vehicles in the lane change target lane are small. The same could apply to a case where the host vehicle and a vehicle in an adjacent lane are traveling in parallel.

[0006] WO 2015 / 052 865 A1 discloses a first inter-vehicle distance that serves as an indicator for a lane change of a home vehicle into an adjacent lane. It is used to decide whether the home vehicle's lane change is enabled or disabled. If a lane change is determined not to be possible, a second inter-vehicle distance before / after the first inter-vehicle distance is used to decide whether the first inter-vehicle distance extends to a length such that a lane change is possible. If a decision is made that such a possibility exists, a decision is made that a waiting time is required. If a decision is made that no such possibility exists, a decision is made that a waiting time is not required.

[0007] DE 101 34 367 A1 discloses a method for guidance when a vehicle changes lanes from a current lane to an adjacent target lane, wherein possible merging gaps are identified from the distances and speeds of objects located there, in particular other vehicles, by means of a simulation of the future movement, and potential merging gaps are signaled to the driver. The method provides that the location and speed of the vehicle are determined, the locations of all other vehicles in the vicinity of the vehicle are transmitted to it, the speed of the other vehicles is either determined by the vehicle from chronologically successive location data or is additionally transmitted to it, and a possible merging gap is determined from the information on the location and speed of the vehicles.

[0008] DE 10 2014 000 843 A1 discloses a method and a driver assistance system for performing a lane change of a vehicle driving autonomously in an actual lane to an adjacent target lane. The method according to the invention is characterized in that the lane change is initiated automatically by the vehicle or by an input in the vehicle, the presence of a traffic gap adequate for the lane change is determined based on first location and movement data of the vehicle and second location and movement data of second vehicles traveling in the target lane, and if an adequate traffic gap is present, the lane change is carried out autonomously by the vehicle.

[0009] DE 10 2005 023 185 A1 discloses a lane change assistant for motor vehicles, with a monitoring device for monitoring the traffic in front of and behind the vehicle and a decision device for deciding whether a safe lane change is possible, characterized by a recommendation device which is designed to calculate the temporal development of vehicle distances in advance and to issue a recommendation for a lane change if this lane change is possible without danger and if the distance to a vehicle driving ahead in the vehicle's own lane will become smaller than a predetermined minimum distance within a predetermined period of time.

[0010] It is desirable to provide a driving assistant for vehicles that makes it possible to support a rapid and safe lane change in response to driving conditions of vehicles in a lane change target lane.

[0011] One aspect of the invention provides a vehicle driving assistant that determines whether or not it is permissible for a host vehicle to enter a lane adjacent to a lane in which the host vehicle is traveling, and provides lane change assistance. The vehicle driving assistant includes a suggested lane change setting unit and a lane change determination unit.The proposed lane change section setting unit sets, based on the relative speeds and relative positions of the own vehicle and a plurality of vehicles traveling in parallel on the adjacent lane, closing time periods in which the own vehicle becomes level with each of the parallel vehicles, and sets, as the proposed lane change section, a section in front of or behind one of the parallel vehicles with which the own vehicle becomes level in the shortest of the closing time periods. The lane change determination unit determines, based on a relative speed calculated from the moving speed of the proposed lane change section and the speed of the own vehicle, when a section distance of the proposed lane change section is equal to or greater than a set value.whether or not it is permissible for the driver's vehicle to enter the proposed lane change section. In a case where the driver's vehicle is located between two parallel vehicles, the average speed of the two parallel vehicles traveling in front of or behind the driver's vehicle serves as the movement speed of the proposed lane change section. In a case where the driver's vehicle is not located between two parallel vehicles, the speed of one of the parallel vehicles closest to the driver's vehicle serves as the movement speed of the proposed lane change section. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows an example of a configuration of a driving assistant for vehicles according to an embodiment of the invention. Fig. 2 shows an example of an own vehicle and parallel vehicles. Fig. Figure 3 shows an example of a proposed lane change section. Fig. 4 is a flowchart of an example lane change assistance process. DETAILED DESCRIPTION

[0012] In the following, some embodiments of the invention are described in detail with reference to the drawings.

[0013] In Fig. In FIG. 1, reference numeral 1 denotes a vehicle such as an automobile. In one embodiment, the vehicle 1 can serve as a "personal vehicle." The personal vehicle 1 can be equipped with a driving assistant 2 that can perform driving assistance control, including autonomous automatic driving, upon a driver's driving operations. The driving assistant 2 can include an external environment detection device that can detect the external environment around the personal vehicle 1 and can be composed of various devices. The driving assistant 2 can receive signals from various sensors that detect driving conditions of the personal vehicle 1.

[0014] In the embodiment, the driving assistant may include a stereo camera unit 3, a side radar unit 4, and a rear radar unit 5 as external environment sensing devices. The stereo camera unit 3 can detect a three-dimensional position of an object in front of the vehicle 1. The side radar unit 4 can detect an object at the front side of the vehicle 1. The rear radar unit 5 can detect an object behind the vehicle 1 using microwaves or other waves. The driving assistant 2 may further include a traffic information communication unit 6. The traffic information communication unit 6 can obtain traffic information using infrastructure communication, such as road-to-vehicle communication or inter-vehicle communication.The stereo camera unit 3, the side radar unit 4, the rear radar unit 5 and the traffic information communication unit 6 may constitute the external environment recognition device that can recognize the external environment of the vehicle 1.

[0015] The stereo camera unit 3 may, for example, include stereo cameras as its main components. The stereo cameras may be composed of two laterally spaced cameras 3a and 3b arranged near the rearview mirror on the inside of a windshield in an upper part of the vehicle interior. The two laterally spaced cameras 3a and 3b may be shutter-synchronized cameras, each including an imaging device such as a CCD (charge-coupled device) and CMOS (complementary metal-oxide semiconductor), and may be mounted with a predetermined baseline length.

[0016] The stereo camera unit 3 may further include an image processor integrated with the stereo cameras. The image processor may perform stereo image processing on a pair of images captured by the side-mounted cameras 3a and 3b to obtain information about a three-dimensional position of a forward object in real space, such as a preceding vehicle. The three-dimensional position of the object may be converted into coordinate values ​​in three-dimensional space based on parallax data and an image coordinate value of the object. In three-dimensional space, for example, a road surface directly below a center point of the stereo cameras may serve as an origin, while a vehicle width direction, a vehicle height direction, and a vehicle length direction, i.e., a distance direction, may serve as axes.The parallax data and image coordinate value of the object can be obtained by stereo image processing.

[0017] The side radar unit 4 may be a short-range radar that detects an object at a relatively short distance around the host vehicle. The side radar unit 4 may be arranged, for example, at the right and left corners of a front bumper. The side radar unit 4 may transmit a radar wave such as a microwave and a millimeter wave with a high frequency band and receive a reflected wave from an object to measure a distance and direction of the object at the front side of the host vehicle. A front temporal zone of the host vehicle may fall outside a field of view of the stereo camera 3. The rear radar unit 5 may be arranged, for example, at the right and left ends of a rear bumper.The rear radar unit 5 can similarly transmit a radar wave and can receive a reflection wave from an object to measure a distance and a direction of the object behind or rear side of the own vehicle.

[0018] Incidentally, the rear object can also be detected by image recognition using a rearview camera, or by sensor fusion of image recognition and data obtained from other sensor devices.

[0019] The traffic information communication unit 6 can receive traffic information through road-to-vehicle communication via road auxiliary devices or inter-vehicle communication with another vehicle. The traffic information may include information about zones that cannot be seen or sensed by the stereo camera unit 3, the side radar unit 4, and the rear radar unit 5, cross streets, and other locations. Incidentally, the traffic information communication unit 6 may be a separate device, but another communication device provided with a positioning device, such as a navigation device, may also serve as the traffic information communication unit 6. The navigation device may include map information of the driving environment, such as the positions of intersections and traffic signals, the number of lanes, the curvature radii of roads, speed limits, and no-overtaking sections.

[0020] The sensors can detect the driving conditions of the host vehicle 1. The sensors can include a speed sensor 10, a steering angle sensor 11, and a gravity (G) sensor 12. The speed sensor 10 can detect a vehicle speed. The steering angle sensor 11 can detect a steering angle. The G-sensor 12 can detect acceleration. The driving assistant 2 can execute the driving assistance control of the vehicle 1 based on the traffic and surrounding information and information about the driving conditions of the host vehicle 1. The traffic and surrounding information can be obtained from the stereo camera unit 3, the side radar unit 4, the rear radar unit 5, and the traffic information communication unit 6. Information about the driving conditions of the host vehicle 1 can be detected by sensors such as the speed sensor 10, the steering angle sensor 11, and the G-sensor 12.

[0021] The driving assistance control of the driving assistant 2 may include a control for supporting a quick and safe lane change. Non-limiting examples of lane changes may include passing or overtaking a preceding vehicle and then returning to the previous lane, and entering an adjacent lane, such as for passing through a highway junction. Therefore, the driving assistant 2 may include, as control functions related to lane changes, a suggested lane change section setting unit 20, a lane change determination unit 21, and a lane change information output unit 22. Thus, the driving assistant 2 can select the most suitable lane change section based on the positional relationship and relative speeds to vehicles in the adjacent lane, allowing lane change assistance in an appropriate, natural manner.

[0022] The proposed lane change section setting unit 20 can detect, based on road lane lines and other data, a lane in which the host vehicle is traveling and an adjacent lane adjacent to the lane in which the host vehicle is traveling. Detection can be performed based on outputs from the stereo camera unit 3, the side radar unit 4, the rear radar unit 5, the speed sensor 10, and other sensors. The proposed lane change section setting unit 20 can measure the presence or absence of a plurality of vehicles in the vicinity of the host vehicle traveling in the adjacent lane. In one embodiment, the plurality of vehicles in the vicinity of the host vehicle traveling in the adjacent lane can serve as "parallel vehicles."The proposed lane change section setting unit 20 can measure the relative speeds and relative positions of the host vehicle to each of the parallel vehicles, as well as the inter-vehicle distances between two parallel vehicles. The proposed lane change section setting unit 20 provides for setting a proposed section where the host vehicle enters the adjacent lane based on the relative speeds and relative positions of the host vehicle to each of the plurality of parallel vehicles. In one embodiment, the proposed section where the host vehicle enters the adjacent lane can serve as a "proposed lane change section."

[0023] In a specific, non-limiting case, the proposed lane change section setting unit 20 provides for setting the proposed lane change section as follows. The proposed lane change section setting unit 20 can, based on the relative positions and the relative speeds of the own vehicle to respective ones of the parallel vehicles, set catching-up periods in which the own vehicle comes into line with respective ones of the parallel vehicles, and can identify one of the parallel vehicles with which the own vehicle comes into line with the same level in the shortest of the catching-up periods. Here, with reference to Fig. 2 describes a case in which a host vehicle C0 is traveling in a lane Lr, and three parallel vehicles C1, C2, and C3 are traveling in the order mentioned in an adjacent lane Lrt. Incidentally, the same can also apply to a case with four or more parallel vehicles.

[0024] Referring to Fig. 2, the traveling direction of the host vehicle C0 and the parallel vehicles C1 to C3 is given as the X direction. The positions of the vehicles are given as X0, X1, X2 and X3. The speeds of the vehicles are given as V0, V1, V2 and V3. Then, the relative speeds Vr1, Vr2 and Vr3 of the host vehicle C1 to the parallel vehicles C1, C2 and C3 can be given by the following expression (1). The relative positions Xr1, Xr2 and Xr3 of the host vehicle C1 to the parallel vehicles C1, C2 and C3 can be given by the following expression (2). The inter-vehicle distances L1 and L2 between any two of the parallel vehicles C1, C2 and C3 can be given by the following expression (3). Vri=Vi−V0 Xri=Xi−X0 Lj=Xj−X(j+1) where i = 1, 2, or 3 j = 1 or 2.

[0025] From expressions (1) to (3), the closing times t1, t2, and t3 in which the host vehicle C0 reaches the same level as the respective parallel vehicles C1, C2, and C3 can be estimated or calculated using the following expression (4). A shortest one of the closing times t1, t2, and t3 can be assigned to a position of one of the parallel vehicles C1 to C3 with which the host vehicle C0 first reaches the same level. A section in front of or behind the one of the parallel vehicles C1 to C3 thus identified can be referred to as the proposed lane change section, i.e., the target section into which the host vehicle C0 enters. ti=Xri / Vri=(Xi−X0) / (Vi−V0) where i = 1, 2 or 3.

[0026] For example, assume that the closing time t3 is the shortest among the closing time t1, t2, and t3, meaning that the host vehicle C0 first reaches the same level as the parallel vehicle C3. Then, the proposed lane change section can be set as shown in Fig. 3, depending on the positional relationship of the own vehicle C0 to the parallel vehicle C3, as shown in (a) and (b) below.

[0027] (a) A case where X3 is smaller than X0 (X3 <X0).

[0028] A section between the parallel vehicles C2 and C3 (a section Lp23 in Fig. 3) can be set as the proposed lane change section.

[0029] (b) A case where X3 is greater than X0 (X3>X0).

[0030] A section behind the parallel vehicle C3 (a section Lp3 in Fig. 3) can be set as the proposed lane change section.

[0031] The same may also apply to a case where the closing time t1 or t2 is the shortest. If the closing time t1 is the shortest, depending on the positional relationship of the host vehicle C0 to the parallel vehicle C1, a section between the parallel vehicles C1 and C2 (a section Lp12 in Fig. 3: X1>X0), or a section in front of the parallel vehicle C1 (a section Lp1 in Fig. 3: X1 <X0) als der vorgeschlagene Fahrspurwechselabschnitt gesetzt werden. Wenn die Aufschließzeitdauer t2 die kürzeste ist, kann, in Abhängigkeit von der Positionsbeziehung des eigenen Fahrzeugs C0 zum parallel fahrenden Fahrzeug C2, ein Abschnitt zwischen den parallel fahrenden Fahrzeugen C2 und C3 (ein Abschnitt Lp23 in Fig. 3: X2>X0), or a section between the parallel vehicles C1 and C2 (a section Lp12 in Fig. 3: X2 <X0) als der vorgeschlagene Fahrspurwechselabschnitt gesetzt werden.

[0032] The lane change determination unit 21 may determine whether the proposed lane change section has a length or section distance long enough to perform the lane change. In one embodiment, the length or section distance may serve as the "length." If the proposed lane change section has a sufficiently long section distance for the lane change, the lane change determination unit 21 may determine whether or not it is permissible to safely perform a lane change based on the speed of the host vehicle and a moving speed of the proposed lane change section.

[0033] Whether the proposed lane change has a sufficiently long section distance to complete the lane change can be determined by comparing the section distance Lk of the proposed lane change section with a set value Lth. The set value Lth can be a value obtained by adding a distance required for the lane change to the vehicle body length of the host vehicle. The set value Lth can be a fixed value preset according to vehicle specifications or can be set variably according to the vehicle speed.

[0034] If the section distance Lk is shorter than the set value Lth (Lk <Lth), kann die Fahrspurwechselbestimmungseinheit 21 bestimmen, dass der Fahrspurwechsel unzulässig ist, und kann die Vorgeschlagener-Fahrspurwechselabschnitt-Setzeinheit 20 anweisen, den vorgeschlagenen Fahrspurwechselabschnitt zurückzusetzen. Die Vorgeschlagener-Fahrspurwechselabschnitt-Setzeinheit 20 kann die Anweisung zum Rücksetzen des vorgeschlagenen Fahrspurwechselabschnitts empfangen, und kann, basierend auf einer nächstkürzesten Aufschließzeitdauer zu der dem zuvor gesetzten vorgeschlagenen Fahrspurwechselabschnitt zugeordneten Aufschließzeitdauer, unter den Aufschließzeitdauern, worin das eigene Fahrzeug zu den jeweiligen der parallel fahrenden Fahrzeugen auf gleiche Höhe kommt, für das Rücksetzen des vorgeschlagenen Fahrspurwechselabschnitt sorgen.

[0035] Incidentally, the proposed lane change section can be considered that the section distance is long enough to perform the lane change (Lk≥Lth) if the proposed lane change section is not a section between two parallel vehicles, for example, the section Lp1 in front of the foremost parallel vehicle C1, or the section Lp3 behind the last parallel vehicle C3, as in Fig. 3 shown.

[0036] Alternatively, the proposed lane change section setting unit 20 may determine whether the proposed lane change section has a section distance long enough for the lane change. If the section distance Lk of the currently set proposed lane change section is shorter than the set value Lth, the proposed lane change section setting unit 20 may sequentially set the proposed lane change section based on the catching-up times. Finally, if no proposed lane change section has a section distance Lk equal to or greater than the set value Lth, for example, a flag may be output indicating that no proposed lane change section exists, and the process may proceed to the next phase.

[0037] On the other hand, if the section distance Lk is equal to or greater than the set value Lth (Lk≥Lth), the lane change determination unit 21 may determine that the lane change is permitted, and may finally determine whether or not it is permitted to safely execute the lane change based on a relative speed calculated from the speed of the host vehicle and the moving speed of the proposed lane change section. The moving speed of the proposed lane change section may be defined according to the positional relationship of the host vehicle to the parallel vehicles, as listed in (c) and (d) below.

[0038] (c) A case where the own vehicle is between two parallel moving vehicles.

[0039] In this case, the average speed of the two parallel vehicles or vehicles traveling behind the own vehicle can serve as the moving speed of the proposed lane change section. When the own vehicle C0 is located between the two parallel vehicles Ci and C(i+1) (where i = 1 or 2), the moving speed Vk of the proposed lane change section can be given by the following expression (5). Vk=(Vi+V(i+1)) / 2 where i = 1 or 2.

[0040] (d) A case where the own vehicle is not between two parallel vehicles.

[0041] In this case, the speed of one of the parallel vehicles closest to the own vehicle can serve as the speed of movement of the proposed lane change section. Fig. In the case illustrated in Figure 2, if the proposed lane change section is located behind the parallel vehicle C3, the moving speed Vk of the proposed lane change section may be equal to V3, as given by the following expression (6). If the proposed lane change section is located in front of the parallel vehicle C1, the moving speed Vk may be equal to V1, as given by the following expression (7). Vk=V3 Vk=V1

[0042] The determination of whether or not it is permissible to perform a safe lane change may be made by comparing an absolute value |Vk-V0| with a threshold value Vth. The absolute value |Vk-V0| may be an absolute value of the relative speed of the host vehicle to the proposed lane change section. The threshold value Vth may be a speed difference, i.e., an absolute value, between the moving speed of the proposed lane change section and a speed that allows the host vehicle to safely reach a position where the lane change is permissible. The threshold value Vth may be appropriately set according to the presence or absence of a vehicle traveling in front of the host vehicle or a vehicle following the host vehicle, a relative speed of the host vehicle to the preceding vehicle or following vehicle, and other conditions.

[0043] If the absolute value |Vk-V0| is greater than Vth (|Vk-V0|>Vth), the lane change determination unit 21 may determine that it is impermissible to execute the lane change into the proposed lane change section. If the absolute value |Vk-V0| is equal to or less than Vth (|Vk-V0|≤Vth), the lane change determination unit 21 may determine that it is permissible to safely execute the lane change into the proposed lane change section. If it is permissible to execute the lane change into the proposed lane change section, the proposed lane change section may be determined as a lane change section into which the host vehicle enters, that is, the lane change section where the host vehicle performs the lane change.For example, if the lane change is performed by automatic driving, the vehicle can be accelerated or decelerated and its steering can be controlled to execute lane change control in the lane change section.

[0044] The lane change information output unit 22 may output audio, video, or any other form of output to provide various information related to the lane change to a driver via an HMI (Human Machine Interface). In a specific but non-limiting embodiment, the lane change information output unit 22 may provide a driver with information, for example, regarding the presence or absence of parallel vehicles, the relative speeds and relative positions of the driver's own vehicle to respective parallel vehicles, the presence of the following vehicle or the preceding vehicle, and the permissibility of the lane change. If the lane change is permitted, the lane change information output unit 22 may output a notification to the driver in the form of audio or video to prompt the driver to perform the lane change.In the case of automatic driving, the lane change can occur automatically.

[0045] In automatic driving, for example, lane changing can occur as follows. The acceleration and deceleration of the host vehicle can be controlled using an electronic throttle device and a brake device (both not shown) to allow the host vehicle to move to a position where lane changing is permitted. A turn signal light can then flash, while a power steering device (not shown) can be activated to allow the host vehicle to move to the lane change section.

[0046] It will now be explained with reference to a flow chart in Fig. 4 describes a program process executed by the driving assistant 2 with regard to the lane change assistance described above.

[0047] In Fig.In the lane change assistance process illustrated in Figure 4, first, in step S1, a measurement is taken based on the driving environment detected based on the outputs from the stereo camera unit 3, the side radar unit 4, the rear radar unit 5, the speed sensor 10, and other sensors. The measurement may include the presence or absence of parallel vehicles in the adjacent lane adjacent to the lane in which the subject vehicle is traveling, the relative speeds and relative positions of the subject vehicle to those of the parallel vehicles, and the inter-vehicle distances between two of the parallel vehicles.

[0048] The flow may then proceed to step S2, wherein the closing times in which the host vehicle comes level with the respective parallel vehicles are estimated based on the relative positions and relative speeds of the host vehicle to the respective parallel vehicles. The proposed lane change section may be set to the section in front of or behind one of the parallel vehicles with which the host vehicle comes level in the shortest closing time. Subsequently, in step S3, a check may be made as to whether or not the section distance Lk of the lane change section proposed as the lane change target is equal to or longer than the set value Lth.

[0049] If in step S3 Lk is smaller than Lth (Lk <Lth), kann der gegenwärtig gesetzte vorgeschlagene Fahrspurwechselabschnitt als zu kurz bestimmt werden, und der Fahrspurwechsel kann als unzulässig bestimmt werden. In diesem Fall kann der Fluss zu Schritt S2 zurückkehren, worin das Rücksetzen des vorgeschlagenen Fahrspurwechselabschnitts erfolgen kann. Wenn hingegen Lk gleich oder größer als Lth ist (Lk≥Lth), kann der gegenwärtig gesetzte vorgeschlagene Fahrspurwechselabschnitt als lang genug bestimmt werden, um den Fahrspurwechsel durchzuführen. In diesem Fall kann der Fluss zu Schritt S4 weitergehen.

[0050] In step S4, it may be determined whether or not it is permissible to safely execute the lane change into the proposed lane change section, given the vehicle speed. As described, the determination of whether or not it is permissible to safely execute the lane change into the proposed lane change section may be made by comparing the absolute value |Vk-V0| with the threshold value Vth. The absolute value |Vk-V0| may be the absolute value of the relative speed between the host vehicle and the proposed lane change section. If the absolute value |Vk-V0| is greater than Vth (|Vk-V0|>Vth), it may be determined that it is impermissible to execute the lane change. In this case, for example, a flag may be reset, and a determination result of the impermissibility of the lane change may be recorded.If the absolute value |Vk-V0| is equal to or less than Vth (|Vk-V0|≤Vth), it can be determined that the lane change is permissible. In this case, a flag can be set, and a determination result of the permissibility of the lane change can be recorded or recorded.

[0051] Next, in step S5, the determination result regarding the lane change, for example, regarding the flag, may be checked. If the lane change is prohibited, the flow may proceed to step S6. In step S6, acceleration or deceleration may be performed to allow the relative speed of the host vehicle to the proposed lane change section to decrease. Afterward, the flow may return to step S1, and the process for setting the proposed lane change section may be performed again while maintaining the driving conditions as they are.

[0052] Conversely, if the lane change is permitted, the flow may proceed from step S5 to step S7, where various information related to the lane change may be output to the HMI. Thereafter, the notification to prompt the driver to perform the lane change may be output in the form of sound or image. In the case of automatic driving, control may be performed that includes accelerating or decelerating the host vehicle to allow the host vehicle to move to a position where the lane change is permitted and flashing the turn signal lamp while allowing the host vehicle to automatically enter the proposed lane change section.

[0053] As described, in the embodiment of the invention, the setting of the proposed lane change is performed based on the relative speeds and relative positions of the host vehicle with respect to each of the plurality of parallel vehicles. Based on the moving speed of the proposed lane change section and the speed of the host vehicle, it is determined whether or not the host vehicle is permitted to enter the proposed lane change section. Thus, it becomes possible to provide prompt and safe lane change assistance in response to the driving conditions of the plurality of parallel vehicles, even when the lane change appears difficult in view of the positional relationship and speed difference between the host vehicle and the plurality of parallel vehicles.

[0054] Although preferred embodiments of the invention have been described above with reference to the accompanying drawings, the invention is by no means limited to the embodiments described above. It is understood that those skilled in the art may make modifications and changes without departing from the scope defined in the claims. The invention is intended to include such modifications and changes insofar as they fall within the scope of the appended claims or their equivalents.

[0055] A vehicle driving assistant provides lane change assistance and includes a suggested lane change section setting unit and a lane change determination unit. The suggested lane change section setting unit sets a suggested lane change section, which is a suggested section where the vehicle enters an adjacent lane, based on the relative speeds and relative positions of the vehicle and a plurality of vehicles traveling in parallel in the adjacent lane. The lane change determination unit determines whether the vehicle is permitted to enter the suggested lane change section based on a moving speed of the suggested lane change section and a speed of the vehicle.

Claims

[1] Driving assistant (2) for vehicles, which determines whether or not it is permissible for an own vehicle (C0) to enter an adjacent lane (Lrt) adjacent to a lane (Lr) in which the own vehicle (C0) is traveling, and provides lane change assistance, the driving assistant (2) for vehicles comprising: a proposed lane change section setting unit (20) which, based on relative speeds and relative positions of the host vehicle (C0) to respective ones of a plurality of vehicles (C1 to C3) traveling in parallel on the adjacent lane (Lrt), sets catching-up periods (t1, t2, and t3) in which the host vehicle (C0) comes to the same level with respective ones of the parallel vehicles (C1 to C3), and sets, as the proposed lane change section (Lp1, Lp3, Lp12, Lp23), a section in front of or behind one of the parallel vehicles (C1 to C3) with which the host vehicle (C0) comes to the same level in a shortest among the catching-up periods (t1, t2, and t3); and a lane change determination unit (21) which, based on a relative speed calculated from the moving speed of the proposed lane change section (Lp1, Lp3, Lp12, Lp23) and the speed of the host vehicle (C0), determines, when a section distance (Lk) of the proposed lane change section (Lp1, Lp3, Lp12, Lp23) is equal to or greater than a set value (Lth), whether or not it is permissible for the host vehicle (C0) to enter the proposed lane change section (Lp1, Lp3, Lp12, Lp23), wherein in a case where the own vehicle (C0) is located between two parallel vehicles (C1 to C3), an average speed of the two parallel vehicles (C1 to C3) traveling in front of or behind the own vehicle (C0) serves as the moving speed of the proposed lane change section (Lp1, Lp3, Lp12, Lp23), and in a case where the own vehicle (C0) is not located between two parallel vehicles (C1 to C3), the speed of one of the parallel vehicles (C1 to C3) closest to the own vehicle (C0) serves as the moving speed of the proposed lane change section (Lp1, Lp3, Lp12, Lp23). [2] Driving assistant (2) for vehicles according to claim 1, wherein, based on the closing time periods (t1, t2 and t3), when a length of the proposed lane change section (Lp1, Lp3, Lp12, Lp23) is less than a set value (Lth), the proposed lane change section (Lp1, Lp3, Lp12, Lp23) is reset. [3] Driving assistant (2) for vehicles according to claim 1 or 2, wherein the lane change determining unit (21) determines that it is permissible for the own vehicle (C0) to enter the proposed lane change section (Lp1, Lp3, Lp12, Lp23) when an absolute value of the relative speed is equal to or less than a threshold value, and the lane change determining unit (21) determines that it is not permissible for the own vehicle (C0) to enter the proposed lane change when the absolute value of the relative speed is greater than the threshold value.

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