Traveling assistance device, traveling assistance method, and storage device

Abstract

A travel assistance device (100) assists a lane change of a host vehicle that is inserted between a plurality of other vehicles traveling on a lane at a lane change destination. The travel assistance device includes a permission / non-permission determination unit (130) that predicts an expansion degree of an inter-vehicle distance between the other vehicles to which the host vehicle is inserted, and determines permission or non-permission of the lane change based on the expansion degree. The travel assistance device includes a trajectory planning unit (140) that determines a lane change trajectory in which the lane change is performed, when the permission of the lane change is determined, and determines a discontinuation trajectory in which the lane change is discontinued, when the non-permission of the lane change is determined.

Description

[0001] Cross-reference to related applications

[0002] This application is based on Japanese Patent Application No. 2020-28411, filed on February 21, 2020, the contents of which are incorporated herein by reference. Technical Field

[0003] The disclosure in this specification relates to driving assistance technologies that assist the vehicle in lane changing. Background Technology

[0004] Patent Document 1 discloses a device for controlling lane changes of a vehicle. This device determines that a lane change is possible and executes the lane change when the inter-vehicle distance between other vehicles at the destination of the lane change is greater than a threshold.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-217829

[0006] In the device of Patent Document 1, if the distance between other vehicles is not guaranteed to be above a threshold before lane change, lane change is not considered possible. Therefore, there is a concern that the device of Patent Document 1 may not be able to easily implement lane changes in lanes where the distance between other vehicles is relatively short. Summary of the Invention

[0007] The purpose of this disclosure is to provide driving assistance devices, driving assistance methods, and storage devices that enable easy lane changes.

[0008] The various methods disclosed in this specification employ different technical units to achieve their respective objectives. Furthermore, the reference numerals enclosed in parentheses in the claims and their items are merely examples indicating the correspondence with specific units described as embodiments described later, and do not limit the scope of the technology.

[0009] One of the disclosed driving assistance devices is a driving assistance device that assists the vehicle in changing lanes when it is inserted between multiple other vehicles traveling in the lane where the lane change destination is located, and includes:

[0010] The prediction unit predicts the extent of the expansion of the inter-vehicle distance between other vehicles that may be cutting into it, and determines whether a lane change is permitted based on the extent of the expansion; and

[0011] The track decision-making department, if it determines that a lane change is permitted, decides to execute the lane change on the designated track; if it determines that a lane change is prohibited, it decides to abort the lane change on the designated track.

[0012] One of the disclosed driving assistance methods is a driving assistance method executed by a processor to assist a vehicle in changing lanes between multiple other vehicles traveling in the lane of the lane change destination, including:

[0013] The prediction process involves forecasting the extent of the lane change between other vehicles that might be intersecting the vehicle, and determining lane change permission based on this forecast.

[0014] The track determines the process: if lane change permission is granted, the track for executing the lane change is determined; if lane change prohibition is granted, the track for interrupting the lane change is determined.

[0015] One disclosed storage device is a storage device that stores a driving assistance program containing commands executed by the processor to assist in lane changes of the vehicle when it is inserted between multiple other vehicles traveling in the lane of the lane change destination.

[0016] Commands include:

[0017] The prediction process involves forecasting the extent of the lane change between other vehicles that might be intersecting the vehicle, and determining lane change permission based on this forecast.

[0018] The track determines the process: if lane change permission is granted, the track for executing the lane change is determined; if lane change prohibition is granted, the track for interrupting the lane change is determined.

[0019] Based on these disclosures, the decision to execute or interrupt a lane change is made by predicting the expansion of the inter-vehicle distance between other vehicles that may be intersecting the vehicle. Therefore, lane changes can be easily permitted even when the inter-vehicle distance before the lane change begins. Based on the above, a driving assistance system, a driving assistance method, and a storage device that can easily execute lane changes can be provided. Attached Figure Description

[0020] Figure 1 This is a diagram showing a system that includes driving assistance devices.

[0021] Figure 2 This is a block diagram illustrating one example of the functions of a driving assistance device.

[0022] Figure 3 These are different charts representing the time-varying changes in workshop distance corresponding to initiative.

[0023] Figure 4 These are different charts that represent the change in speed over time corresponding to initiative.

[0024] Figure 5 This is a diagram illustrating an example of a method for predicting the extent of expansion.

[0025] Figure 6 This is a diagram illustrating an example of a method for predicting the extent of expansion.

[0026] Figure 7 This is a flowchart illustrating an example of a driving assistance method performed by a driving assistance device.

[0027] Figure 8 This is a detailed flowchart illustrating the process of determining whether or not permission is granted. Detailed Implementation

[0028] (First Implementation)

[0029] Reference Figures 1 to 8 The driving assistance device of the first embodiment will be described. The driving assistance device of the first embodiment is provided by an electronic control unit, namely a driving assistance ECU 100, mounted on the vehicle A. The vehicle A has at least one of an automatic driving function and a high-level driving assistance function. The driving assistance ECU 100 predicts the movement of moving objects around the vehicle A and assists the driving of the vehicle A based on the prediction results. Figure 1 As shown, the driving assistance ECU 100 is connected to the locator 10, the perimeter monitoring ECU 20, the vehicle speed sensor 30, the vehicle communicator 40, and the vehicle control ECU 50 via a communication bus, etc.

[0030] The locator 10 generates vehicle location information by combining multiple composite positioning signals. The locator 10 includes a GNSS (Global Navigation Satellite System) receiver 11, an inertial sensor 12, a map database (hereinafter referred to as map DB) 13, and a locator ECU 14. The GNSS receiver 11 receives positioning signals from multiple positioning satellites. The inertial sensor 12 is a sensor that detects the inertial forces acting on the vehicle A. The inertial sensor 12 includes, for example, a three-axis gyroscope sensor and a three-axis accelerometer sensor, detecting the angular velocity and acceleration acting on the vehicle A.

[0031] Map DB13 is a non-volatile memory that stores map information such as route data, node data, terrain, and structures. Map information may include, for example, a 3D map composed of feature points of terrain and structures. Furthermore, the 3D map can also be generated from captured images using REM (Road Experience Management). Additionally, the map information may include road sign information, traffic restriction information, road construction information, and weather information. The map information stored in Map DB13 is updated periodically or continuously based on the latest information received by the vehicle-mounted communicator 40.

[0032] The locator ECU 14 is configured to primarily consist of a microcomputer equipped with a processor, memory, input / output interfaces, and a bus connecting them. The locator ECU 14 sequentially measures the position of the vehicle A (hereinafter referred to as the vehicle position) by combining the positioning signal received by the GNSS receiver 11, map data from the map DB 13, and measurement results from the inertial sensor 12. The vehicle position can be represented, for example, by latitude and longitude coordinates. Alternatively, the vehicle position can be determined using the travel distance calculated from signals sequentially output from the vehicle speed sensor 30 mounted on the vehicle A. When using a three-dimensional map composed of feature points of road shapes and structures as map data, the locator ECU 14 can also be configured to determine the vehicle position using the three-dimensional map and the detection results from the surrounding monitoring sensor 25, without using the GNSS receiver 11. The locator ECU 14 sequentially provides the vehicle position information, the acceleration information of the vehicle A, and map information of the surrounding area of ​​the vehicle A to the driving assistance ECU 100.

[0033] The perimeter monitoring ECU 20 is mainly composed of a microcomputer with a processor, memory, input / output interfaces, and a bus connecting them. It performs various processes by executing control programs stored in the memory. The perimeter monitoring ECU 20 acquires detection results from the perimeter monitoring sensors 25 and identifies the vehicle's driving environment based on these detection results.

[0034] The surrounding surveillance sensor 25 is an autonomous sensor that monitors the surrounding environment of vehicle A. It includes LiDAR (Light Detection and Ranging / Laser Imaging Detection and Ranging) for detecting feature points of ground objects, and a surrounding surveillance camera for capturing images of a predetermined area in front of vehicle A. Additionally, the surrounding surveillance sensor 25 may also include millimeter-wave radar and sonar.

[0035] The surrounding monitoring ECU 20, for example, analyzes and processes point cluster images acquired from LiDAR and images captured by surrounding monitoring cameras to identify the presence, location, and speed of other vehicles around vehicle A. The surrounding monitoring ECU 20 then provides this information related to other vehicles as other vehicle information to the driving assistance ECU 100.

[0036] The vehicle-to-everything (V2N) communicator 40 is a communication module installed in vehicle A. The V2N communicator 40 has at least the capability for V2N (Vehicle to Cellular Network) communication based on communication standards such as LTE (Long Term Evolution) and 5G, enabling it to transmit and receive signals with base stations around vehicle A. The V2N communicator 40 may also have vehicle-to-roadside infrastructure (V2I) communication and vehicle-to-vehicle (V2V) communication capabilities. Furthermore, the V2N communicator 40 can obtain information from other vehicles via V2V communication and provide it to the driving assistance ECU 100. The V2N communicator 40 can also facilitate cloud-to-car collaboration between the vehicle and the cloud system. Through the installation of the V2N communicator 40, vehicle A becomes a connected car capable of connecting to the Internet.

[0037] The vehicle control ECU 50 is an electronic control device that performs acceleration / deceleration control and steering control of vehicle A. The vehicle control ECU 50 includes a steering control ECU for steering control, a power unit control ECU for acceleration / deceleration control, and a braking ECU. The vehicle control ECU 50 acquires detection signals from various sensors mounted on vehicle A, such as the steering angle sensor and vehicle speed sensor 30, and outputs control signals to various driving control devices, such as the electronic throttle valve, brake actuator, and EPS (Electric Power Steering) motor. The vehicle control ECU 50 obtains the trajectory plan (described later) from the driving assistance ECU 100 and controls the various driving control devices to achieve automatic driving or highly assisted driving corresponding to the trajectory plan.

[0038] The driving assistance ECU 100 assists vehicle A in lane changing based on information from the aforementioned components. The driving assistance ECU 100 is configured to include a computer as its main body, comprising a memory 101, a processor 102, input / output interfaces, and buses connecting them. The processor 102 is hardware used for computational processing. The processor 102 may include at least one of the following as its core: a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or a RISC (Reduced Instruction Set Computer) CPU.

[0039] The memory 101 is a non-transitory tangible storage medium, such as semiconductor memory, magnetic media, and optical media, capable of being read by a computer, that stores or transmits programs and data. The memory 101 stores various programs, such as driving assistance programs described later, that are executed by the processor 102.

[0040] The processor 102 executes multiple commands contained in the driving assistance program stored in the memory 101. Thus, the driving assistance ECU 100 constructs multiple functional units for assisting vehicle A in lane changes when it inserts itself between other vehicles traveling in the lane of its destination lane. In this way, the program stored in the memory 101 in the driving assistance ECU 100 causes the processor 102 to execute multiple commands, thereby constructing multiple functional units. Specifically, as... Figure 2 As shown, the driving assistance ECU 100 includes functional units such as a need determination unit 110, a position setting unit 120, a permission determination unit 130, and a track planning unit 140.

[0041] The lane change determination unit 110 determines whether a lane change is necessary. Specifically, the lane change determination unit 110 determines whether the current driving scenario requires a lane change based on the driving route to the destination, map information around the vehicle A, and information on other vehicles around the vehicle A.

[0042] For example, the need-to-change determination unit 110 determines that a lane change is necessary in scenarios where the current lane cannot reach the destination or requires a detour (a difficult-to-reach scenario). Difficult-to-reach scenarios include situations where the driver is traveling in a lane other than the right-turn lane when a right turn is required at an intersection, traveling in a lane on a branch road heading in a direction different from the destination, and traveling in a lane not adjacent to the exit lane when exiting a highway. Furthermore, the need-to-change determination unit 110 determines that a lane change is necessary in merging scenarios where the driver is traveling in a merging lane. Additionally, the need-to-change determination unit 110 determines that a lane change is necessary in scenarios where continued travel in the current lane is restricted due to construction, accidents, obstacles, etc. Finally, the need-to-change determination unit 110 determines that a lane change is necessary in scenarios where other vehicles traveling at low speeds are overtaking in the current lane.

[0043] In addition, the necessity determination unit 110 determines whether the necessity of a lane change is within the permissible range when it determines that a lane change is necessary. Specifically, if the current driving scenario is any one of a difficult-to-reach scenario, a merging scenario, or a restricted scenario, the necessity determination unit 110 determines that the necessity of a lane change is outside the permissible range. On the other hand, if the current driving scenario is an overtaking scenario, the necessity determination unit 110 determines that the necessity is within the permissible range. In other words, if it is difficult to reach the destination without a lane change, or if continuing to drive is difficult, the necessity determination unit 110 determines that the necessity is outside the permissible range. The necessity determination unit 110 sequentially provides the determination result of whether a lane change is necessary and the determination result of the necessity when it is determined to be necessary to the position setting unit 120. The necessity determination unit 110 is an example of a "necessity determination unit".

[0044] The position setting unit 120 sets the predicted starting position for the degree of expansion between other vehicles. Specifically, the position setting unit 120 acquires information about other vehicles traveling in the lane to which the lane change destination is located (the lane to which the lane change destination is located), and determines the other vehicles that will be the preceding and following vehicles of the current vehicle A after the lane change. In other words, the position setting unit 120 determines the lane change destination space that the current vehicle A will enter through the lane change. For example, the position setting unit 120 can select, for example, two other vehicles within the detection range of the surrounding monitoring sensor 25 that have the largest inter-vehicle distance as the preceding and following vehicles after the lane change.

[0045] Furthermore, the position setting unit 120 estimates the aggressiveness 'a' for the determined following vehicle. Aggressiveness 'a' is an indicator representing the behavioral characteristics of other vehicles in response to changes in inter-vehicle distance. Specifically, aggressiveness 'a' is the behavioral characteristic of bringing the actual inter-vehicle distance closer to the target inter-vehicle distance when the actual inter-vehicle distance (i.e., the actual inter-vehicle distance) differs from the assumed target inter-vehicle distance (target inter-vehicle distance) of other vehicles. When the actual inter-vehicle distance is larger than the target inter-vehicle distance, such as... Figure 3 As shown, the greater the initiative 'a', the more likely it is to shorten the workshop distance in a shorter time. Additionally, as... Figure 4 As shown, the greater the initiative 'a', the more likely it is to accelerate to a higher speed in a short time and then decelerate more quickly afterward.

[0046] The position setting unit 120 calculates the initiative degree 'a' using a learned model adjusted by machine learning. For example, a learned model can be generated through teacher-guided learning based on a dataset containing the temporal changes in the position and speed of the following vehicle as input data and the initiative degree 'a' as output data. If a following vehicle is determined, the position setting unit 120 observes the following vehicle's position 'xi' and speed 'vi' for a predetermined time (e.g., several seconds) to acquire input data. The position setting unit 120 sequentially provides information on the preceding and following vehicles, along with the estimated initiative degree 'a', to the permission determination unit 130. Furthermore, the position setting unit 120 instructs the track planning unit 140 to generate a preparation track for moving ahead of the following vehicle in the currently traveling lane and preparing for lane changes.

[0047] The lane change determination unit 130 predicts the extent of the expansion of the inter-vehicle distance between other vehicles intervening in the insertion of vehicle A, based on the preceding and following vehicles determined by the position setting unit 120, and determines whether a lane change is permitted, i.e., whether a lane change can be permitted. The lane change determination unit 130 assumes a spring model with the preceding and following vehicles as mass points and predicts the expansion extent based on this spring model. Specifically, the lane change determination unit 130 estimates the negative acceleration (deceleration) of the following vehicles intervening in the insertion of vehicle A based on the action of the spring model, and predicts the expansion extent based on this deceleration. The deceleration for the insertion of vehicle A is the deceleration expected by the following vehicles as they assume they make a yielding action to the forward insertion of vehicle A, leaving sufficient inter-vehicle distance. Hereinafter, this deceleration will be described as "expected deceleration".

[0048] Reference Figure 5 , 6An example of a method for calculating the expected deceleration is given. Assume other vehicles B, C, and D are traveling in a lane changing destinations. Let the speed of other vehicle B be vi-1 and its position xi-1, the speed of other vehicle C be vi and its position xi, and the speed of other vehicle D be vi+1 and its position xi+1. Here, each position xi-1, xi, and xi+1 is its position in the direction of extension of the current lane. Furthermore, let the actual inter-vehicle distance between other vehicle B and other vehicle C be δi. If the inter-vehicle time is set to h and the minimum inter-vehicle distance is set to δmin, then the ideal inter-vehicle distance (target inter-vehicle distance) δi between other vehicle B and other vehicle C can be expressed using the following formula (1). - Furthermore, in formula (1), the workshop target value δi - This is represented by an overline above δi. - The symbol.

[0049] [Formula 1]

[0050]

[0051] Here, the workshop time h and the minimum workshop distance δmin are design parameters based on actual vehicle test results or simulation results. According to formula (1), the following formula (2) expresses the value relative to the workshop target value δi. - The deviation ei of the actual workshop distance δi.

[0052] [Equation 2]

[0053] e i =hv i +δ min -δ i …(2) Here, it is assumed that other vehicles C, through acceleration and deceleration control, bring the current actual vehicle-to-vehicle distance δi toward the ideal vehicle-to-vehicle distance, i.e., the target vehicle-to-vehicle distance δi. - Convergence, that is, the deviation ei converges to 0. At this time, the action based on the spring model, using the deviation ei and the degree of initiative a, can be regarded as the following relationship of formula (3) holds.

[0054] [Formula 3]

[0055]

[0056] Here, if the acceleration of the other vehicle C that makes the deviation ei converge is set as ui, then according to formula (2) and formula (3), the relationship of the following formula (4) holds.

[0057] [Formula 4]

[0058]

[0059] like Figure 6 As shown, when vehicle A changes lanes in front of another vehicle C, the other vehicle C identifies vehicle A as the new leading vehicle after the lane change begins. In this case, it can be assumed that the other vehicle C aims to converge the actual inter-vehicle distance δi with the new leading vehicle, i.e., vehicle A, to the target inter-vehicle distance δi. - The acceleration ui is generated. The acceleration ui in the deceleration direction, that is, the negative value of the acceleration ui, becomes the expected deceleration of other vehicles C due to the insertion of this vehicle A. Based on the above, the expected deceleration can be calculated based on formula (4) and the following formula (5). In addition, vi-1 in formula (4) can be replaced with the velocity ve of this vehicle A.

[0060] [Formula 5]

[0061] δ i =x e -x i …(5)

[0062] Furthermore, the timing at which other vehicles C recognize vehicle A as a new preceding vehicle can be, for example, when ye > l / 2 and xe ≥ xi. Here, ye is the lateral (vehicle width direction) separation distance of vehicle A from the lane center L1c of the current lane, and l is the interval between the lane center L1c and the lane center L2c of the destination lane. The permission determination unit 130 obtains the vehicle's position xe from the locator ECU 14, the vehicle's speed ve from the vehicle speed sensor 30, and the following vehicle's position xi and speed vi from the surrounding monitoring ECU 20. Alternatively, the permission determination unit 130 can also obtain the following vehicle's position xi and speed vi through vehicle-to-vehicle communication.

[0063] The lane change determination unit 130 predicts the extent of the expansion of the inter-vehicle distance for yielding actions by a following vehicle that is intersecting with vehicle A, based on the expected deceleration calculated above. Then, the lane change determination unit 130 determines whether or not a lane change is permitted based on the predicted expansion. For example, if the lane change determination unit 130 determines that the state in which a following vehicle can intersect with vehicle A without collision has lasted for a predetermined period, it determines that a lane change is permitted. Conversely, if the lane change determination unit 130 determines that the state in which a non-collision intersects with vehicle A has not lasted for the predetermined period, it determines that a lane change is not permitted. The lane change determination unit 130 begins the above lane change determination, for example, at the stage of reaching the front of the following vehicle. The lane change determination unit 130 repeatedly performs the above lane change determination until the lane change is completed.

[0064] Furthermore, the permission determination unit 130 calculates the parameters required for generating the lane change track (hereinafter referred to as the LC track) T1 based on the expected deceleration. Specifically, the permission determination unit 130 uses three parameters as determining variables: the starting position of the lane change, the starting speed of the lane change, and the time from the start to the completion of the lane change (completion time). It calculates each parameter by solving an optimization problem. For example, the permission determination unit 130 uses a fifth-order polynomial and other assumed LC track T1 to search for parameters that minimize the abrupt change (jump) of the current vehicle A and subsequent vehicles during the lane change. The permission determination unit 130 provides the calculated parameters to the track planning unit 140.

[0065] Furthermore, if the lane change determination unit 130 determines that the necessity of lane change is within the permissible range, it interrupts the prediction of other vehicles' actions based on the degree of expansion between other vehicles. In this case, the lane change determination unit 130 performs a lane change permission determination based on linear prediction. Specifically, the lane change determination unit 130 calculates the inter-vehicle distance at the start of the lane change, assuming the current speeds of all other vehicles are maintained, based on the speeds and positions of the preceding and following vehicles. Then, if the calculated inter-vehicle distance is above a threshold, the lane change determination unit 130 determines that lane change is permissible; if the inter-vehicle distance is below the threshold, the lane change is not permissible. Alternatively, the lane change determination unit 130 may calculate the collision margin between other vehicles and vehicle A instead of the inter-vehicle distance, and perform the lane change determination based on the collision margin. The lane change determination unit 130 sequentially provides either a lane change determination result based on expected deceleration or a lane change determination result based on linear prediction to the track planning unit 140. The permission / disapproval determination unit 130 is an example of a "prediction unit".

[0066] The track planning unit 140 determines the travel track of vehicle A. For example, based on information from the position setting unit 120, the track planning unit 140 generates a preparation track for lane changing by entering the lane changing destination space from the side. Then, if the permission determination unit 130 determines that lane changing is permissible, the track planning unit 140 generates an LC track T1 from the start position to the end position of the lane change. The track planning unit 140 determines the LC track T1 using the start position, start speed, and completion time of the lane change calculated by the permission determination unit 130.

[0067] Additionally, if the permission determination unit 130 determines that lane changes are not permitted, the track planning unit 140 generates an interrupted track T2, which is a track that interrupts lane changes. Figure 6As shown, the interrupted track T2 is the track on which the vehicle continues to travel in the current driving lane. Furthermore, the track planning unit 140 can pre-generate both the LC track T1 and the interrupted track T2 before determining whether permission is granted, and decide on the track to be used based on the permission determination result. The track planning unit 140 provides the generated driving tracks T1 and T2 sequentially to the vehicle control ECU 50. The track planning unit 140 is an example of a "track determination unit".

[0068] Next, refer to the following Figure 2 and according to Figure 7 , 8 The flow of the driving assistance method, which is implemented through the cooperation of functional units and by the driving assistance ECU 100 executing the driving assistance program, will be explained. Figure 7 , 8 In this context, lane changing is referred to as "LC". Furthermore, in the process described later, "S" refers to multiple steps in the process executed through multiple commands included in the driving assistance program.

[0069] First of all Figure 7 In step S10, the necessity determination unit 110 determines whether a lane change is necessary. If it determines that a lane change is not necessary, the process ends. If it determines that a lane change is necessary, the process proceeds to step S20. In step S20, the necessity determination unit 110 determines whether the necessity of the lane change is within the permissible range. If it determines that the necessity is outside the permissible range, the process proceeds to step S30.

[0070] In S30, the position setting unit 120 determines the preceding and following vehicles and calculates the initiative 'a' of the following vehicles. Next, in S40, the position setting unit 120 determines the predicted starting positions of other vehicles' movements and completes preparation for lane changing. In S40, if the predicted starting positions cannot be determined, the system returns to S30 to re-determine the preceding and following vehicles.

[0071] If the preparation for lane changing is completed in S40, then in S50, the permission determination unit 130 performs a permission determination that takes into account the yielding action of the following vehicle. In other words, the permission determination unit 130 predicts the extent of the expansion of the inter-vehicle distance between the preceding vehicle and the following vehicle for the insertion of this vehicle A, and determines whether the lane change can be permitted based on the prediction result.

[0072] Reference Figure 8The processing of S50 performed by the permission determination unit 130 is explained in detail. First, in S51, the positions and speeds of the preceding and following vehicles are obtained. Next, in S52, the actions of the following vehicle are simulated. Specifically, based on the estimate of the expected deceleration, the extent of the expansion of the inter-vehicle distance for insertion of vehicle A is calculated. Then, in S53, based on the simulation results, it is determined whether insertion is permissible. Specifically, in S53, if it can be determined that the following vehicle will not collide with vehicle A, insertion is deemed permissible; if it can be determined that a collision will occur, insertion is deemed inadmissible.

[0073] If it is determined in S53 that insertion is permissible, then in S54, the counter is incremented. Conversely, if it is determined in S53 that insertion is not permissible, then in S55, the counter is reset to zero. After S54 or S55, in S56, it is determined whether the counter count has reached the permitted lane change value (LC permitted value). If it is determined that the permitted value has been reached, then in S57, the determination that lane change is permissible is made.

[0074] On the other hand, if it is determined in S56 that the permitted value has not been reached, then in S58, it is determined whether the permitted time has elapsed since the start of the count. If it is determined that the permitted time has not elapsed, then it returns to S51. On the other hand, if it is determined that the permitted time has elapsed, then in S59, a determination is made that lane changing is not permitted. If either S57 or S59 is executed, then proceed to... Figure 7 The S70.

[0075] On the other hand, in S20, if the necessity of lane changing is determined to be within the permissible range, the process proceeds to S60. In S60, similar to S40, the position setting unit 120 determines the predicted start position of other vehicle movements and completes the preparation for lane changing. In S60, if the predicted start position cannot be determined, the preparation for lane changing is attempted again by re-determining the preceding and following vehicles. If the preparation for lane changing is completed in S60, then in S65, the permission determination unit 130 performs a permission determination for lane changing based on a linear prediction of other vehicle movements.

[0076] After executing either S50 or S65, in S70, the track planning unit 140 determines whether a lane change permission determination or a prohibition determination was made in the permission / prohibition determination. If a permission determination is made, in S80, the track planning unit 140 decides that LC track T1 is the running track. Through S80, lane changing begins if it is before lane changing begins, and continues if lane changing is in progress.

[0077] On the other hand, if a lane change prohibition is determined, in S90, the track planning unit 140 decides to suspend track T2 as the driving track. Through S90, if the lane change has not yet begun, driving continues in the lane before the lane change; if a lane change is underway, the system resumes driving in the lane before the lane change.

[0078] Furthermore, S20 is an example of a "necessity determination process", S50 is an example of a "prediction process", and S80 and S90 are examples of "track determination processes".

[0079] Next, the effects of the first implementation method will be explained.

[0080] According to the first embodiment, based on the prediction of the expansion of the inter-vehicle distance between other vehicles B and C that are intervening in front of vehicle A, it is determined whether to execute or interrupt a lane change. Therefore, even when the inter-vehicle distance before the lane change begins is relatively short, lane changes can be easily permitted. Based on the above, lane changes can be easily executed.

[0081] Furthermore, according to the first embodiment, the degree of expansion is predicted based on a spring model that assumes other vehicles as point masses. Therefore, it is possible to simulate the interaction of actions between multiple other vehicles and reflect this in the decision of permission.

[0082] In addition, according to the first embodiment, for other vehicles C that become following vehicles A after a lane change, the expected deceleration for the insertion of vehicle A is estimated, and the extent of expansion is predicted based on the expected deceleration. Therefore, it is possible to reflect the degree of deceleration of following vehicles due to the lane change of vehicle A in the decision on whether or not permission is granted.

[0083] Furthermore, according to the first embodiment, the expected deceleration is estimated based on the behavior characteristics of other vehicles C in response to changes in inter-vehicle distance, thus enabling more accurate prediction of the behavior of other vehicles C. Additionally, according to the first embodiment, the timing of starting a lane change after reaching the front of another vehicle C is determined based on the extent of expansion, thus enabling more reliable initiation of lane changes.

[0084] In addition, according to the first embodiment, it is determined whether the necessity of lane changing is within the permissible range. If the necessity is determined to be within the permissible range, the determination of whether lane changing is permitted based on the degree of expansion is interrupted. Therefore, it is possible to use the determination of whether lane changing is permitted separately when the necessity of lane changing is high and low. In particular, in the first embodiment, the determination of whether lane changing is permitted is performed without considering or inserting the corresponding degree of expansion, so when the necessity of lane changing is low, lane changing can be performed with more leeway in the inter-vehicle distance.

[0085] (Other implementation methods)

[0086] The disclosure in this specification is not limited to the illustrated embodiments. The disclosure includes the illustrated embodiments and modifications that can be made by those skilled in the art based on these embodiments. For example, the disclosure is not limited to the combination of components and / or elements shown in the embodiments. The disclosure can be implemented in a wide variety of combinations. The disclosure can have additional portions that can be added to the embodiments. The disclosure includes embodiments with components and / or elements omitted. The disclosure includes substitutions or combinations of components and / or elements between one embodiment and other embodiments. The scope of the disclosure is not limited to the description of the embodiments. It should be understood that some scopes of the disclosure are shown by the description of the claims and include all modifications within the meaning and scope equivalent to the description of the claims.

[0087] In the above embodiment, the necessity determination unit 110 determines whether the necessity of lane changing is within the permissible range based on the type of driving scenario requiring lane changing. Alternatively, the necessity determination unit 110 may determine whether the necessity of lane changing is within the permissible range based on the remaining distance of the vehicle A to a specific location. In this case, if the remaining distance to the specific location is above a threshold distance, the necessity determination unit 110 determines that the necessity is within the permissible range; if the remaining distance is below the threshold distance, the necessity is determined to be outside the permissible range. The specific location can be, for example, a location where lane changing is practically impossible if the vehicle passes through. Specifically, the specific location could be a right-turn point in a right-turn lane lane changing scenario, a branch point in a branch road lane changing scenario, or the end of a merging lane in a merging scenario, etc.

[0088] The driving assistance ECU 100 can also be a dedicated computer comprising at least one of digital circuitry and analog circuitry as a processor. Specifically, the digital circuitry includes at least one of the following: ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), SOC (System on a Chip), PGA (Programmable Gate Array), and CPLD (Complex Programmable Logic Device). Furthermore, such digital circuitry may also include a memory storing the program.

[0089] The driving assistance ECU 100 can be provided via a single computer or a group of computer resources linked via a data communication device. For example, some of the functions provided by the driving assistance ECU 100 in the above embodiments can also be implemented by other ECUs.

Claims

1. A travel assist apparatus that assists a lane change of a host vehicle that is inserted between a plurality of other vehicles traveling on a lane at a lane change destination, wherein The above-described travel assistance device includes: a prediction unit that predicts an expansion degree of an inter-vehicle distance between the other vehicles into which the host vehicle is inserted, and determines permission or non-permission of the lane change based on the expansion degree; a track determination unit that determines a lane change track in which the lane change is performed, in a case where the permission of the lane change is determined, and determines a discontinuance track in which the lane change is discontinued, in a case where the non-permission of the lane change is determined; and a necessity determination unit that determines whether a necessity of the lane change is within an allowable range, in a case where it is determined that the necessity is within the allowable range, the prediction unit discontinues the determination of the permission or non-permission of the lane change based on the expansion degree, and performs determination of the permission or non-permission of the lane change based on a linear prediction of behavior of the other vehicles, the prediction unit estimates an aggressiveness of the other vehicle that becomes a following vehicle of the host vehicle after the lane change, the aggressiveness being an index indicating a behavior characteristic of the other vehicle that reacts to a change in an actual inter-vehicle distance with respect to a target inter-vehicle distance, and the greater the aggressiveness, the shorter the time in which the other vehicle that becomes the following vehicle of the host vehicle after the lane change adjusts the inter-vehicle distance, the prediction unit estimates a deceleration into which the host vehicle is inserted, based on the aggressiveness of the other vehicle that becomes the following vehicle of the host vehicle after the lane change, and estimates an expansion degree of the inter-vehicle distance based on a spring model, based on the deceleration.

2. The travel assistance device according to claim 1, wherein the prediction unit determines a start timing of the lane change after reaching a front of the other vehicle that becomes the following vehicle of the host vehicle after the lane change, based on the expansion degree. The above-described travel assistance method includes:

3. A travel assistance method that is executed by a processor in order to assist a lane change of a host vehicle that is to be inserted between a plurality of other vehicles traveling on a lane at a lane change destination, wherein a prediction process of predicting an expansion degree of an inter-vehicle distance between the other vehicles into which the host vehicle is inserted, and determining permission or non-permission of the lane change based on the expansion degree; a track determination process of determining a lane change track in which the lane change is performed, in a case where the permission of the lane change is determined, and determining a discontinuance track in which the lane change is discontinued, in a case where the non-permission of the lane change is determined; and a necessity determination process of determining whether a necessity of the lane change is within an allowable range, in a case where it is determined that the necessity is within the allowable range, in the prediction process, the determination of the permission or non-permission of the lane change based on the expansion degree is discontinued, and determination of the permission or non-permission of the lane change based on a linear prediction of behavior of the other vehicles is performed, in the prediction process, an aggressiveness of the other vehicle that becomes a following vehicle of the host vehicle after the lane change is estimated, the aggressiveness being an index indicating a behavior characteristic of the other vehicle that reacts to a change in an actual inter-vehicle distance with respect to a target inter-vehicle distance, and the greater the aggressiveness, the shorter the time in which the other vehicle that becomes the following vehicle of the host vehicle after the lane change adjusts the inter-vehicle distance, in the prediction process, a deceleration into which the host vehicle is inserted is estimated, based on the aggressiveness of the other vehicle that becomes the following vehicle of the host vehicle after the lane change, and an expansion degree of the inter-vehicle distance based on a spring model is estimated, based on the deceleration. In the prediction process, an aggressiveness of the other vehicle that becomes a following vehicle of the host vehicle after the lane change is estimated based on the expansion degree, and a deceleration of the host vehicle for the insertion is estimated based on the expansion degree.

4. The travel assist method according to claim 3, wherein In the prediction process, a start timing of the lane change after reaching in front of the other vehicle that becomes a following vehicle of the host vehicle after the lane change is determined based on the expansion degree.

5. A storage device storing a travel assist program, the travel assist program including commands for causing a processor to execute in order to assist a lane change of a host vehicle that is inserted between a plurality of other vehicles traveling on a lane at a lane change destination, wherein The commands include: a prediction process that predicts an expansion degree of an inter-vehicle distance between the other vehicles for the insertion of the host vehicle, and determines permission or prohibition of the lane change based on the expansion degree; a track determination process that determines a lane change track in which the lane change is performed when the permission of the lane change is determined, and determines a discontinuation track in which the lane change is discontinued when the prohibition of the lane change is determined; and a necessity determination process that determines whether a necessity of the lane change is within an allowable range, when it is determined that the necessity is within the allowable range, in the prediction process, the determination of the permission or prohibition of the lane change based on the expansion degree is discontinued, and a permission or prohibition determination of the lane change based on a linear prediction of a behavior of the other vehicles is performed, In the prediction process, an aggressiveness of the other vehicle that becomes a following vehicle of the host vehicle after the lane change is estimated based on the expansion degree, and a deceleration of the host vehicle for the insertion is estimated based on the expansion degree.

6. The storage device according to claim 5, wherein In the prediction process, a start timing of the lane change after reaching in front of the other vehicle that becomes a following vehicle of the host vehicle after the lane change is determined based on the expansion degree. ​

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