Driving assistance system, driving assistance program, and driving assistance method

Abstract

According to the present invention, a processor of a driving assistance system for assisting avoidance of collision with an object during driving of a host vehicle is configured to execute: turning control of the host vehicle in an avoidance direction (Da) for avoiding collision before the risk of collision of the host vehicle with the object increases to a collision avoidance range in which the host vehicle is requested to perform collision avoidance; and cooperative control of a braking force (Fb) and a steering angle (θs) that are applied to a wheel from an actuator system in response to the collision risk reaching the collision avoidance range in the host vehicle that has been subjected to the turning control in the avoidance direction (Da), in accordance with a drive trajectory (Td) planned for the host vehicle to achieve collision avoidance.

Description

Driving assistance system, driving assistance program, driving assistance method CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2023-190329 filed in Japan on November 7, 2023, and the contents of the original application are incorporated by reference in their entirety.

[0002] The present disclosure relates to a driving assistance technology that assists a vehicle driver in avoiding a collision with a target.

[0003] The technology disclosed in Patent Document 1 controls the steering torque output to an actuator in order to avoid a collision of a vehicle with a target.

[0004] Japanese Patent Application Laid-Open No. 2021-11227

[0005] However, in the technology disclosed in Patent Document 1, even when the vehicle is decelerated by braking, the target steering angle is merely set according to the amount of lateral movement on the driving trajectory required to avoid a predicted collision. As a result, if the steering torque for providing the target steering angle according to the amount of lateral movement is controlled high by the correction gain, there is a concern that insufficient lateral movement may occur due to a delay in the steering angle response of the actuator. This interferes with the vehicle's accurate tracing of the driving trajectory to avoid a collision, and therefore, from the perspective of safety and security, improvement was needed to ensure a margin for collision avoidance.

[0006] An object of the present disclosure is to provide a driving assistance system that is effective for avoiding a collision between a vehicle and a target. Another object of the present disclosure is to provide a driving assistance program that is effective for avoiding a collision between a vehicle and a target. Yet another object of the present disclosure is to provide a driving assistance method that is effective for avoiding a collision between a vehicle and a target.

[0007] The technical means of the present disclosure for solving the problems will be described below.

[0008] A first aspect of the present disclosure is a driving assistance system having a processor that assists a host vehicle in avoiding a collision with a target when driving the host vehicle, wherein the processor is configured to: control the host vehicle to turn in an avoidance direction toward collision avoidance before the risk of collision between the host vehicle and the target increases to a collision avoidance range that requires the host vehicle to avoid the collision; and, in response to the collision risk of the host vehicle that has been controlled to turn in the avoidance direction reaching the collision avoidance range, cooperatively control the braking force and steering angle applied to the wheels from the actuator system in accordance with a driving trajectory planned for the host vehicle toward collision avoidance.

[0009] A second aspect of the present disclosure is a driving assistance program stored in a storage medium to assist in avoiding a collision with a target when driving a host vehicle, and including instructions to cause a processor to execute the assistance, the instructions including: turning control of the host vehicle in an avoidance direction toward collision avoidance before the risk of collision of the host vehicle with the target increases to a collision avoidance range that requires the host vehicle to avoid collision; and cooperative control of the braking force and steering angle applied to the wheels from the actuator system in accordance with a driving trajectory planned for the host vehicle toward collision avoidance in response to the collision risk of the host vehicle that has been turned in the avoidance direction reaching the collision avoidance range.

[0010] A third aspect of the present disclosure is a driving assistance method executed by a processor to assist in avoiding a collision with a target when driving a host vehicle, the method including: controlling the host vehicle to turn in an avoidance direction toward collision avoidance before the risk of collision between the host vehicle and the target increases to a collision avoidance range that requires the host vehicle to avoid the collision; and cooperatively controlling the braking force and steering angle applied to the wheels from an actuator system in accordance with a driving trajectory planned for the host vehicle toward collision avoidance in response to the collision risk reaching the collision avoidance range in the host vehicle that has been controlled to turn in the avoidance direction.

[0011] According to these first to third aspects, the host vehicle is controlled to turn in an avoidance direction toward collision avoidance before the risk of collision between the host vehicle and the target object rises to a collision avoidance range that requires the host vehicle to avoid collision. As a result, in response to the collision risk reaching the collision avoidance range in the host vehicle that has been controlled to turn in the avoidance direction, the braking force and steering angle applied to the wheels by the actuator system are cooperatively controlled according to the driving trajectory planned for the host vehicle toward collision avoidance. This allows for the host vehicle to accurately trace the driving trajectory and ensure a margin for collision avoidance from the perspective of safety and security, thereby realizing driving assistance that is effective in avoiding a collision between the host vehicle and a target object.

[0012] FIG. 1 is a block diagram showing the physical configuration of a driving assistance system according to a first embodiment. FIG. 2 is a schematic diagram showing a traveling environment of a host vehicle to which the first embodiment is applied. FIG. 3 is a block diagram showing the functional configuration of a driving assistance system according to the first embodiment. FIG. 4 is a flowchart showing a driving assistance flow according to the first embodiment. FIG. 5 is a graph for explaining the driving assistance flow according to the first embodiment. FIG. 6 is a flowchart showing a driving assistance flow according to a second embodiment. FIG. 7 is a graph for explaining the driving assistance flow according to the second embodiment. FIG. 8 is a flowchart showing a driving assistance flow according to a third embodiment. FIG. 9 is a graph for explaining the driving assistance flow according to the third embodiment.

[0013] Hereinafter, multiple embodiments of the present disclosure will be described with reference to the drawings. Note that corresponding components in each embodiment are designated by the same reference numerals, and redundant description may be omitted. Furthermore, when only a portion of the configuration is described in each embodiment, the configuration of another previously described embodiment may be applied to the remaining portions of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of multiple embodiments may be partially combined together even if not explicitly stated, provided that there is no particular problem with the combination.

[0014] (First Embodiment) A driving assistance system 1 of a first embodiment shown in FIG. 1 assists in driving a host vehicle 2. At least a portion of the driving assistance system 1 is mounted on the host vehicle 2. The host vehicle 2 to which the driving assistance system 1 is applied may be capable of achieving a level of automated driving specified in, for example, SAE J3016, at which a manual driving assistance task exists that assists an operator in performing manual driving operations, along with an automated driving task. Such a host vehicle 2 is a road user, such as a car or a truck, and may also be referred to as an ego-vehicle. As described above, the driving assistance system 1, as the operator of the host vehicle 2, provides driving assistance to a driver who is aboard the host vehicle 2 and is capable of performing manual driving operations.

[0015] As shown in FIG. 2 , the driving environment in which the host vehicle 2 travels includes at least one of the following types of targets 3 other than the host vehicle 2: other road users, obstacles, and structures. The other road users include non-vulnerable road users and vulnerable road users. The non-vulnerable road users are at least one type of moving body with a human on board, such as a car, truck, motorcycle, or bicycle. The vulnerable users are, for example, pedestrians. The obstacles include at least one type of construction signboard, work signboard, or fallen object. The structures include at least one type of building, road structure, traffic light, or road sign.

[0016] 1, a host vehicle 2 is equipped with an actuator system 4, a sensor system 5, a communication system 6, a map database (DB) 7, and an information presentation system 8, along with at least a part of a driving assistance system 1. However, FIG. 1 representatively shows an example in which the entire driving assistance system 1 implemented in the form of a processing circuit (e.g., a processing ECU) or a semiconductor device (e.g., a semiconductor chip) is equipped in the host vehicle 2.

[0017] The actuator system 4 is configured to be able to control the driving behavior of the host vehicle 2 based on control commands from the driving assistance system 1. As shown in Fig. 3, the actuator system 4 includes at least one type of power train actuator 40, such as an internal combustion engine or a motor-generator-motor. The actuator system 4 also includes at least one type of steering actuator 42, such as a power steering unit. The actuator system 4 also includes at least one type of braking actuator 44, such as a brake unit.

[0018] 2, the host vehicle 2 has a plurality of wheels 20 including front wheels 20fl, 20fr and rear wheels 20rl, 20rr. The brake actuator 44 independently adjusts the braking forces Fb applied to the front wheels 20fl, 20fr and the rear wheels 20rl, 20rr as braking forces (see FIG. 5, described later) to be applied to the host vehicle 2. This allows the host vehicle 2 to control the left-right and front-rear distribution of the braking forces Fb.

[0019] On the other hand, the steering actuator 42 adjusts at least one of the steering angle θs common to the front wheels 20fl, 20fr and the steering angle θs common to the rear wheels 20rl, 20rr as the steering angle (see FIG. 5 described later) to be applied to the host vehicle 2. As a result, particularly in the first embodiment, in the host vehicle 2 in which the common steering angle θs of the front wheels 20fl, 20fr and the common steering angle θs of the rear wheels 20rl, 20rr are adjusted independently of each other, it becomes possible to control the front / rear distribution of these common steering angles.

[0020] 1 , the sensor system 5 senses the external and internal environments of the host vehicle 2 to obtain sensing information that can be used in the driving assistance system 1. To this end, the sensor system 5 includes an external sensor 50 and an internal sensor 52.

[0021] The external sensor 50 senses targets 3 that exist in the external world of the host vehicle 2. The target sensing type external sensor 50 is at least one type of sensor selected from the group consisting of an image sensor (i.e., an on-board camera), a LiDAR (light detection and ranging / laser imaging detection and ranging), a laser sensor, a millimeter wave sensor, and a sonar sensor. The target sensing type external sensor 50 may be implemented by combining multiple types of sensors so as to be capable of sensing the front, side, and rear directions of the host vehicle 2.

[0022] The internal sensor 52 senses a specific physical quantity of motion related to vehicle motion in the internal environment of the host vehicle 2. The internal sensor 52 of the motion sensing type is at least one of, for example, a speed sensor, an acceleration sensor, a gyro sensor, etc. The internal sensor 52 may sense the operation or state of occupants, including the driver, riding in the internal environment of the host vehicle 2. The internal sensor 52 of the occupant sensing type is at least one of, for example, an accelerator pedal sensor, a steering angle sensor, a steering torque sensor, a brake pedal sensor, a shift sensor, an occupant camera, a steering switch, a biosensor, a seating sensor, and an in-vehicle device switch, etc.

[0023] The communication system 6 acquires communication information usable in the driving assistance system 1 via wireless communication. The communication system 6 may receive positioning signals from satellites of a global navigation satellite system (GNSS) present in the external world of the host vehicle 2. The positioning-type communication system 6 is, for example, a GNSS receiver. The communication system 6 may transmit and receive communication signals to and from a V2X system present in the external world of the host vehicle 2. The V2X communication-type communication system 6 is, for example, at least one of a dedicated short range communications (DSRC) communication device and a cellular V2X (C-V2X) communication device. The communication system 6 may transmit and receive communication signals to and from a mobile terminal present in the internal world of the host vehicle 2. The terminal communication-type communication system 6 is, for example, at least one of a Bluetooth (registered trademark) device, a Wi-Fi (registered trademark) device, an infrared communication device, etc.

[0024] The map DB 7 stores map information that can be used in the driving assistance system 1. The map DB 7 includes at least one type of non-transitory tangible storage medium, such as a semiconductor memory, a magnetic medium, or an optical medium. The map DB 7 may be a DB of a locator that estimates the self-position of the host vehicle 2. The map DB may be a DB of a navigation unit that navigates the driving route of the host vehicle 2. The map DB 7 may be constructed by combining multiple types of DBs.

[0025] The map DB 7 acquires and stores the latest map information, for example, through V2X communication with an external center via the communication system 6. The map information is converted into two-dimensional or three-dimensional data as information representing the external environment in which the host vehicle 2 is traveling. Digital data of a high-precision map may be used as the three-dimensional map information. The map information includes road information representing at least one of the following: the position, shape, and road surface condition of a road structure. The map information may also include structure information representing at least one of the following: the position, shape, and other information of buildings and traffic lights facing the road. The map information may also include marking information representing at least one of the following: the position, shape, and other information of signs and lane markings attached to the road.

[0026] The information presentation system 8 presents notification information to occupants, including the driver, of the host vehicle 2. The information presentation system 8 presents notification information by stimulating the vision of the occupants in the host vehicle 2. The information presentation system 8 of the visual information presentation type is, for example, at least one of an in-vehicle monitor, a head-up display (HUD), a combination meter, a navigation unit, and an illumination unit. The information presentation system 8 may present notification information by stimulating the auditory sense of the occupants. The information presentation system 8 of the auditory information presentation type is, for example, at least one of a speaker, a buzzer, and a vibration unit. The information presentation system 8 may present notification information by stimulating the cutaneous sense of the occupants. The information presentation system 8 of the cutaneous sense information presentation type is, for example, at least one of a vibration unit, a reaction force unit, and an air conditioning unit.

[0027] The driving assistance system 1 is connected to an actuator system 4, a sensor system 5, a communication system 6, a map DB 7, and an information presentation system 8 via at least one of, for example, a local area network (LAN), a wire harness, an internal bus, or a wireless communication line. The driving assistance system 1 is configured to include at least one dedicated computer.

[0028] The dedicated computer constituting the driving assistance system 1 may be an integrated ECU (electronic control unit) that integrates the driving control of the host vehicle 2. The dedicated computer constituting the driving assistance system 1 may be a sensing ECU that processes sensing information in the driving control of the host vehicle 2. The dedicated computer constituting the driving assistance system 1 may be a recognition ECU that recognizes the external world in the driving control of the host vehicle 2. The dedicated computer constituting the driving assistance system 1 may be a locator ECU that estimates the self-position of the host vehicle 2.

[0029] The dedicated computer constituting the driving assistance system 1 may be a planning ECU that plans driving control of the host vehicle 2. The dedicated computer constituting the driving assistance system 1 may be a navigation ECU that navigates a driving route in driving control of the host vehicle 2. The dedicated computer constituting the driving assistance system 1 may be an actuator ECU that controls the actuator system 4 as part of driving control of the host vehicle 2.

[0030] The dedicated computer constituting the driving assistance system 1 may be an information management ECU that controls the information presentation system 8 as part of driving control of the host vehicle 2. The dedicated computer constituting the driving assistance system 1 may also be at least one external computer that constitutes, for example, an external center or a mobile terminal that can communicate via the communication system 6.

[0031] The dedicated computer constituting the driving assistance system 1 has at least one memory 10 and one processor 12. The memory 10 is at least one type of non-transitory tangible storage medium, such as a semiconductor memory, a magnetic medium, or an optical medium, that non-temporarily stores computer-readable programs and data. The processor 12 includes at least one type of core, such as a central processing unit (CPU), a graphics processing unit (GPU), or a reduced instruction set computer (RISC)-CPU.

[0032] The processor 12 executes a plurality of instructions included in a driving assistance program stored as software in the memory 10. In this way, the driving assistance system 1 constructs a plurality of functional blocks for carrying out driving assistance processing for the host vehicle 2. The plurality of functional blocks constructed by the driving assistance system 1 in this way include an operation judgment block 100, a trajectory generation block 120, and a driving control block 140 shown in FIG.

[0033] The operation determination block 100 acquires sensing information from the sensor system 5. The operation determination block 100 generates operation data by determining the driver's manual driving operation of the host vehicle 2 based on the acquired sensing information. The operation data related to the manual driving operation may represent at least one type of operation parameter corresponding to the driver's operation, such as the accelerator pedal operation amount, steering operation angle, steering operation torque, brake pedal operation amount, and shift operation position.

[0034] The trajectory generation block 120 acquires sensing information from the sensor system 5. The trajectory generation block 120 acquires communication information from the communication system 6. The trajectory generation block 120 acquires map information from the map DB 7. The trajectory generation block 120 acquires data of past control commands to the host vehicle 2 from the driving control block 140. The trajectory generation block 120 processes this acquired information and data individually and then fuses them to generate recognition data that recognizes the external environment and internal environment of the host vehicle 2. In this way, the recognition data generated by the trajectory generation block 120 represents the state of the external environment and internal environment recognized for each driving scene in which the host vehicle 2 travels.

[0035] Specifically, the trajectory generation block 120 may generate the recognition data by localization that recognizes the self-state of the host vehicle 2. The recognition data regarding the self-state may represent at least one type of physical quantity of motion, such as position, velocity, acceleration, jerk, yaw rate, and yaw angle, which appear in the host vehicle 2 in accordance with a control command from the driving control block 140, which will be described in detail later. The trajectory generation block 120 may generate the recognition data by recognizing a target 3 in the external world of the host vehicle 2. The recognition data regarding the target 3 may represent at least one type of physical quantity of motion, such as separation distance, direction of motion, relative velocity, relative acceleration, and time to collision (TTC) with the host vehicle 2.

[0036] The trajectory generation block 120 plans a target driving trajectory Td (see FIG. 2) for future driving of the host vehicle 2 based on the generated recognition data. The driving trajectory Td specifies time-series changes for each control cycle expected in the future beyond the present regarding motion parameters that are targets for the host vehicle 2's own state. Specifically, the driving trajectory Td may represent position coordinates for each control cycle of a trajectory that the host vehicle 2 is to follow in the future. Furthermore, the driving trajectory Td may represent at least one type of physical quantity of motion, such as speed, acceleration, jerk, yaw rate, and yaw angle, as motion parameters to be revealed for each control cycle on such a trajectory.

[0037] The driving control block 140 acquires operation data from the operation judgment block 100. The driving control block 140 acquires data on the driving trajectory Td from the trajectory generation block 120, along with the recognition data. The driving control block 140 acquires data on past control commands to the host vehicle 2 by reading it from the memory 10. The driving control block 140 generates control commands for controlling the driving behavior of the host vehicle 2 based on this acquired data. At this time, a control command is generated to be issued to the actuator system 4 so as to control a driving task corresponding to the autonomous driving level adjusted to suit the driving scene, out of the autonomous driving task and the manual driving assistance task in the host vehicle 2. The control command generated in this manner is stored in the memory 10.

[0038] Examples of driving tasks corresponding to the autonomous driving level include adaptive cruise control (ACC), autonomous emergency braking (AEB), and lane keeping assist (LKA). Therefore, adjusting the autonomous driving level may include a handover in which the driving task is transferred between the driving assistance system 1 and the driver by transitioning the driving mode between the autonomous driving task and the manual driving assistance task. Such a handover is realized at least at one of the following times: a driver's request for handover; a move toward or away from an autonomous driving operational design domain (ODD); and a required time for a minimum risk maneuver (MRM).

[0039] (Driving Assistance Flow) In the first embodiment, a driving assistance flow that realizes a driving assistance method for assisting driving of the host vehicle 2 is repeatedly executed according to Fig. 4 by cooperation of multiple blocks 100, 120, and 140. Note that in the following explanation, each "S" in the driving assistance flow refers to multiple steps that are executed by multiple commands included in the driving assistance program.

[0040] 4, the trajectory generation block 120 determines whether a pre-avoidance condition, which requires advance preparation for avoiding a collision with a target 3 in a future travel of the host vehicle 2, is met. The pre-avoidance condition is met when the collision risk between the host vehicle 2 and the target 3 reaches a pre-avoidance range, which is lower than the collision avoidance range, before the collision risk rises to the collision avoidance range that requires the host vehicle 2 to avoid the collision. Therefore, whether the collision risk has reached the pre-avoidance range is determined based on the recognition data generated by the trajectory generation block 120. In this case, the collision risk may be determined to have reached the avoidance range when the TTC becomes equal to or less than a pre-threshold time (e.g., 2.3 seconds).

[0041] If a negative determination is made in S10 because the pre-avoidance conditions are not met, the current driving assistance flow ends. On the other hand, if a positive determination is made in S10 because the pre-avoidance conditions are met, the current driving assistance flow proceeds to S20. In S20, the trajectory generation block 120 sets an avoidance control period Pa as shown in FIG. 5 in order to carry out control of the host vehicle 2 to avoid a collision.

[0042] In S30 shown in FIG. 4 , the trajectory generation block 120 determines whether a collision avoidance condition, which requires the host vehicle 2 to avoid a collision with the target 3 in future travel, has been met. The collision avoidance condition is met when the collision risk between the host vehicle 2 and the target 3 exceeds the pre-avoidance range of S10 and rises to a collision avoidance range that requires the host vehicle 2 to avoid a collision. Therefore, whether the collision risk has reached the collision avoidance range is determined based on the recognition data generated by the trajectory generation block 120. In this case, the collision risk may be determined to have reached the collision avoidance range when the TTC is equal to or less than a threshold time (e.g., 2.0 seconds). The collision risk may also be determined to have reached the collision avoidance range when, in addition to these TTC requirements, the probability of collision avoidance, for example, by changing lanes, is equal to or greater than a threshold.

[0043] If a negative determination is made in S30 because the collision avoidance conditions are not met, the current driving assistance flow sequentially proceeds to S40, S50, and S60. That is, the sequential transition from S30 to S40, S50, and S60 is realized in response to the risk of collision between the host vehicle 2 and the target 3 reaching a pre-avoidance range that is lower than the collision avoidance range.

[0044] In S40, the trajectory generation block 120 plans a driving trajectory Td to be traced by the host vehicle 2 over a pre-control period Pap, which is a period before the collision avoidance condition is met, within the avoidance control period Pa shown in FIG. 5 , in preparation for avoiding a collision with the target object 3 during future travel of the host vehicle 2. At this time, the driving trajectory Td is planned so as to define, for each control cycle, the time-series change in the required yaw rate Y_c as well as the trajectory representing the time-series change in the position coordinates as a motion parameter to be targeted during future travel of the host vehicle 2. However, during the pre-control period Pap, the magnitude of the required yaw rate Y_c is planned to be essentially zero, as shown in FIG. 5. Note that, although the sign of the required yaw rate Y_c in FIG. 5 is defined around the yaw axis of the host vehicle 2 in a top view, with the counterclockwise direction being positive and the clockwise direction being negative, it is of course possible to define the opposite relationship.

[0045] 4, the driving control block 140 generates a control command to the actuator system 4 to perform turning control (yawing control) of the host vehicle 2 in the avoidance direction Da to avoid a collision. At this time, the avoidance direction Da is preferably set to one of the left turning direction and the right turning direction about the yaw axis from the longitudinal axis of the host vehicle 2, which direction follows the driving trajectory Td planned in S40. However, it is possible to imagine driving scenarios in which it is difficult or impossible to determine the avoidance direction Da from the planned driving trajectory Td. In such imagined scenarios, it is preferable to obtain a predicted probability of the avoidance direction Da in future driving based on at least one of the recognition data from the trajectory generation block 120 and the driving trajectory Td, and select the avoidance direction Da with a high predicted probability.

[0046] In S50, the driving control block 140 of the first embodiment generates a control command to the brake actuator 44 to control the attitude of the host vehicle 2 in the avoidance direction Da by adjusting the left / right distribution of the braking force Fb applied to each wheel 20 of the host vehicle 2. At this time, the control command controls the left / right distribution of the braking force Fb to the front wheels 20fl, 20fr and the left / right distribution of the braking force Fb to the rear wheels 20rl, 20rr so that turning in the avoidance direction Da can be achieved with a slight actual yaw rate. Note that, although the sign of the braking force Fb in Figure 5 is defined as negative when the host vehicle 2 is moving backward, it may of course be defined as positive.

[0047] 5 , when the avoidance direction Da is a left turning direction, a control command is generated to apply a braking force Fb to the left front wheel 20fl and left rear wheel 20rl, which are on the inside wheels of the host vehicle 2, at a magnitude that brings the difference between the required yaw rate Y_c, which is substantially zero, and the actual yaw rate determined by the control command within a small allowable range. At this time, when the host vehicle 2 is in a driver override state due to manual driving operation, the braking forces Fb applied to the left front wheel 20fl and left rear wheel 20rl may be corrected within the range of the difference within the allowable range based on operation data from the operation judgment block 100. Furthermore, when the avoidance direction Da is a left turning direction, a control command is generated to apply a braking force Fb, which is substantially zero, to the right front wheel 20fr and right rear wheel 20rr, which are on the outside wheels of the host vehicle 2.

[0048] When the avoidance direction Da is a right turning direction, similar to the case of a left turning direction, a control command is generated to apply a braking force Fb to the right front wheel 20fr and right rear wheel 20rr, which are on the inside wheels of the host vehicle 2, with a magnitude that brings the difference between the required yaw rate Y_c, which is substantially zero, and the actual yaw rate based on the control command within a small allowable range. At this time, when the host vehicle 2 is in a driver override state through manual driving operation, the braking forces Fb applied to the right front wheel 20fr and right rear wheel 20rr may be corrected within the range of the difference within the allowable range based on operation data from the operation judgment block 100. Furthermore, when the avoidance direction Da is a right turning direction, similar to the case of a left turning direction, a control command is generated to apply a braking force Fb, with a magnitude that is substantially zero, to the left front wheel 20fl and left rear wheel 20rl, which are on the outside wheels of the host vehicle 2.

[0049] In S60 shown in FIG. 4, the driving control block 140 determines whether the pre-control period Pap in the current driving assistance flow has ended. If a negative determination is made during the pre-control period Pap, the current driving assistance flow returns to S50, and the next control cycle begins. On the other hand, if a positive determination is made upon completion of the pre-control period Pap, the current driving assistance flow returns to S30, and the next control cycle begins. As described above, during the pre-control period Pap, the braking force Fb applied to each wheel 20 is controlled to an appropriate value at an appropriate time required for turning control in the avoidance direction Da. That is, during the pre-control period Pap, the yawing of the host vehicle 2 follows the control command of S50, and the actual yaw angle of the host vehicle 2 is optimized in the avoidance direction Da to avoid a collision, as illustrated in FIG. 5. Furthermore, in the event that, for example, the TTC exceeds or increases to the pre-threshold time in response to the driver's collision avoidance action by at least one of braking and steering, the current driving assistance flow may be terminated at S60, and normal control of the driving task may be carried out on the host vehicle 2 until the next time the pre-avoidance condition is met.

[0050] 4, if a positive determination is made because the collision avoidance conditions are met, the current driving assistance flow sequentially advances to S70, S80, and S90. That is, the sequential advancement from S30 to S70, S80, and S90 is realized in response to the host vehicle 2, which has been subjected to turning control (yawing control) in the avoidance direction Da in response to the control command during the pre-control period Pap, reaching the collision avoidance range.

[0051] In S70, the trajectory generation block 120 plans a driving trajectory Td to be traced by the host vehicle 2 over the emergency control period Pae from the establishment of the collision avoidance condition within the avoidance control period Pa shown in Fig. 5, in order to avoid a collision with the target object 3 in the future traveling of the host vehicle 2. At this time, the driving trajectory Td is planned so as to specify, for each control period, the time-series change in the required yaw rate Y_c as shown in Fig. 5, in addition to the trajectory that is the time-series change in the position coordinates, as the motion parameter to be targeted in the future traveling of the host vehicle 2.

[0052] In S80 shown in FIG. 4, the driving control block 140 generates a control command to the actuator system 4 based on the driving trajectory Td planned in S70 to move the host vehicle 2 toward collision avoidance. At this time, the control command is generated so as to cooperatively control the braking force Fb and steering angle θs applied to each wheel 20 of the host vehicle 2 in accordance with each motion parameter represented by the driving trajectory Td, as shown in FIG. 5. Here, cooperative control refers to the concept of controlling the braking force Fb and the steering angle θs in a mutually cooperative manner, and is understood to include a control state in which, as a result of this cooperation, one is controlled to a substantially zero value and the other is variably adjusted. Note that the sign of the steering angle θs in FIG. 5 is defined in accordance with the required yaw rate Y_c, with the counterclockwise direction being positive and the clockwise direction being negative around the yaw axis from the longitudinal axis of the host vehicle 2 in a top view, but of course the opposite relationship may also be used.

[0053] Specifically, the control command in S80 controls the common steering angle θs of the front wheels 20fl, 20fr to a magnitude that correlates with the required yaw rate Y_c in the left turning direction when the required yaw rate Y_c is positive as illustrated in the period Pael in Fig. 5 during the emergency control period Pae. The control command in S80 controls the common steering angle θs of the front wheels 20fl, 20fr to a magnitude that correlates with the required yaw rate Y_c in the right turning direction when the required yaw rate Y_c is negative as illustrated in the period Paer in Fig. 5 during the emergency control period Pae.

[0054] In either of these periods Pael and Paer, the control command in S80 may also control the distribution of the common steering angles θs between the front and rear wheels 20rl and 20rr by correlating the common steering angle θs of the rear wheels 20rl and 20rr with the required yaw rate Y_c when the common steering angle θs of the front wheels 20fl and 20fr can be adjusted independently. Furthermore, in either of the periods Pael and Paer, the control command in S80 may control the left-right distribution of the braking force Fb applied to the front wheels 20fl and 20fr and the braking force Fb applied to the rear wheels 20rl and 20rr correlated with the required yaw rate Y_c as shown in Figure 5. Here, Figure 5 illustrates the left-side braking force Fb during the period Pael, and does not illustrate the right-side braking force Fb during the period Paer. 5, a control command may be generated to generate a required amount of left-side braking force Fb in the period Paer and / or a required amount of right-side braking force Fb in the period Pael. In addition to the above, in either period Pael or Paer, when the host vehicle 2 is in a driver override state due to manual driving operation, the control command in S80 may correct each common steering angle θs and each braking force Fb within the range of the above-mentioned control requirements based on operation data from the operation judgment block 100.

[0055] The control command at S80 is preferably generated so that the maximum left and right lateral movement amounts δL appearing in the host vehicle 2 are averaged on the left and right sides over the avoidance control period Pa that follows the control command at S50, as illustrated in FIG. 5 . That is, during the avoidance control period Pa, which extends from the start of turning control during the pre-control period Pap to the end of cooperative control during the emergency control period Pae, averaging control is preferably performed to average the maximum left and right lateral movement amounts δL in cooperation with the turning control and emergency control. That is, averaging control of the maximum lateral movement amount δL means controlling the maximum left lateral movement amount resulting from a left turn and the maximum right lateral movement amount resulting from a right turn to be substantially the same on the host vehicle 2. Note that, although the signs of the lateral movement amounts, including the maximum lateral movement amount δL, are defined in FIG. 5 as being positive for the left lateral movement amount and negative for the right lateral movement amount, they may of course be defined as being inversely related.

[0056] In S90 shown in FIG. 4, the driving control block 140 determines whether the emergency control period Pae in the current driving assistance flow has ended. If a negative determination is made during the emergency control period Pae, the current driving assistance flow returns to S80, and the next control cycle begins. On the other hand, if a positive determination is made upon completion of the emergency control period Pae, the current driving assistance flow ends. As described above, during the emergency control period Pae, the steering angle θs of each wheel 20, together with the braking force Fb as necessary, is controlled to a timely and appropriate value required for cooperative control. That is, even during the emergency control period Pae, which is subsequent to the pre-control period Pap, the yawing of the host vehicle 2 follows the control command of S80, and the actual yaw angle of the host vehicle 2 is optimized for collision avoidance, as illustrated in FIG. 5. By ending the current driving assistance flow at S90 and the above-described S10, normal control of the driving task may be performed on the host vehicle 2 until the next time the pre-avoidance condition is satisfied.

[0057] (Operations and Effects) Operations and effects of the first embodiment described above will be described below.

[0058] According to the first embodiment, the host vehicle 2 is controlled to turn in the avoidance direction Da toward collision avoidance before the risk of collision between the host vehicle 2 and the target 3 increases to a collision avoidance range that requires the host vehicle 2 to avoid collision. As a result, in response to the collision risk of the host vehicle 2, which has been controlled to turn in the avoidance direction Da, reaching the collision avoidance range, the braking force Fb and steering angle θs applied to the wheels 20 by the actuator system 4 are cooperatively controlled according to the driving trajectory Td planned for the host vehicle 2 toward collision avoidance. According to this, even if a response delay of the braking force Fb and / or the steering angle θs occurs in the actuator system 4, the insufficient lateral movement of the host vehicle 2 in the cooperative control can be resolved by performing the turning control during a period where the risk is lower than the collision avoidance range. Therefore, the host vehicle 2 can be accurately traced along the driving trajectory Td, ensuring a margin for collision avoidance from the perspective of safety and security, thereby enabling effective driving assistance for the host vehicle 2 to avoid a collision with the target 3.

[0059] According to the first embodiment, the host vehicle is controlled to turn in the avoidance direction Da in response to the collision risk reaching the pre-avoidance range, where the collision risk is lower than the collision avoidance range. Thus, even if a response delay occurs in the actuator system 4 with the braking force Fb and / or the steering angle θs, the turning control is performed at an appropriate time to reach the pre-avoidance range, where the collision risk is lower than the collision avoidance range, so that the insufficient lateral movement of the host vehicle 2 in the cooperative control can be accurately resolved. Therefore, the host vehicle 2 can be made to trace the driving trajectory Td with high accuracy, ensuring a margin for collision avoidance, making it possible to achieve highly reliable driving assistance for the host vehicle 2 to avoid a collision with the target 3.

[0060] According to the first embodiment, the host vehicle 2 is controlled to turn in the avoidance direction Da by allocating the braking force Fb applied to the wheels 20 from the brake actuator 44 to the left and right sides. As a result, in the host vehicle 2 controlled to turn in the avoidance direction Da, the steering angle θs applied to the wheels 20 from the steering actuator 42 and the braking force Fb from the brake actuator 44 are cooperatively controlled according to the driving trajectory Td. As a result, even if a delay in the response of the braking force Fb from the brake actuator 44 and / or a delay in the response of the steering angle θs from the steering actuator 42 occurs, turning control utilizing the left and right allocation of the braking force Fb can be performed while the risk is low, thereby making it possible to increase the amount of lateral movement. Therefore, a margin for collision avoidance can be secured while substantially maintaining the steering angle θs and the steering operation angle that determines it, thereby making it possible to provide driving assistance that is effective for avoiding a collision between the host vehicle 2 and the target 3, and that provides peace of mind to the driver.

[0061] In the turning control and cooperative control according to the first embodiment, averaging control is performed to average the maximum lateral movement amount δL that appears in the host vehicle 2 during the avoidance control period Pa from the start of turning control to the end of cooperative control, on the left and right sides of the host vehicle 2. This makes it possible to stably manifest the desired behaviors on the left and right sides of the host vehicle 2 through the turning in the avoidance direction Da and the subsequent coordination of the braking force Fb and steering angle θs. Therefore, driving assistance that is effective for avoiding a collision with the target object 3 in the host vehicle 2 makes it possible to realize vehicle behavior that gives the driver a sense of security.

[0062] The turning control and cooperative control according to the first embodiment may be performed in a driver override state for the host vehicle 2. In this case, even in response to the driver override, the host vehicle 2 can be made to exhibit the desired behaviors, namely, turning in the avoidance direction Da and subsequent coordination of the braking force Fb and steering angle θs. Therefore, even in the host vehicle 2 in which manual driving operation by the driver is expected, it is possible to achieve driving assistance that is effective in avoiding a collision with the target 3.

[0063] Second Embodiment The second embodiment is a modified example of the first embodiment. As shown in FIG. 6 , in the driving assistance flow of the second embodiment, S2050 is executed instead of S50. For this reason, in the second embodiment, the steering actuator 42 adjusts both the common steering angle θs of the front wheels 20fl, 20fr and the common steering angle θs of the rear wheels 20rl, 20rr. As a result, in the second embodiment, the front / rear distribution of the common steering angle θs of the front wheels 20fl, 20fr and the common steering angle θs of the rear wheels 20rl, 20rr can be controlled.

[0064] In detail below, in S2050, the driving control block 140 of the second embodiment generates a control command to the brake actuator 44 to control the attitude of the host vehicle 2 in the avoidance direction Da by the front / rear distribution of the steering angle θs to be applied to each wheel 20 of the host vehicle 2. At this time, the control command controlling the front / rear distribution of the common steering angle θs of the front wheels 20fl, 20fr and the common steering angle θs of the rear wheels 20rl, 20rr limits the distribution of the steering angle θs matched with the avoidance direction Da to the rear wheels 20rl, 20rr, thereby making it possible to realize turning with a slight actual yaw rate.

[0065] 7, when the avoidance direction Da is a left turning direction, a control command is generated to impart a negative clockwise common steering angle θs to the rear wheels 20rl, 20rr, with a magnitude that keeps the difference between the required yaw rate Y_c, which is substantially zero, and the actual yaw rate according to the control command within a small allowable range. At this time, when the host vehicle 2 is in a driver override state through manual driving operation, the common steering angle θs of the rear wheels 20rl, 20rr may be corrected within the range of the difference within the allowable range based on operation data from the operation judgment block 100. Furthermore, when the avoidance direction Da is a left turning direction, a control command is generated to impart a common steering angle θs, which is substantially zero, to the front wheels 20fl, 20fr.

[0066] When the avoidance direction Da is a right-turning direction, similar to the case of a left-turning direction, a control command is generated to impart a counterclockwise common steering angle θs with a positive sign to the rear wheels 20rl, 20rr, with a magnitude that keeps the difference between the required yaw rate Y_c, which is substantially zero, and the actual yaw rate based on the control command within a small allowable range. At this time, if the host vehicle 2 is in a driver override state through manual driving operation, the common steering angle θs of the rear wheels 20rl, 20rr may be corrected within the range of the difference within the allowable range based on operation data from the operation judgment block 100. Furthermore, when the avoidance direction Da is a right-turning direction, similar to the case of a left-turning direction, a control command is generated to impart a common steering angle θs of substantially zero to the front wheels 20fl, 20fr.

[0067] (Operations and Effects) Operations and effects specific to the second embodiment described above will be described below.

[0068] According to the second embodiment, the host vehicle 2 is controlled to turn in the avoidance direction Da by the front / rear allocation of the steering angle θs applied to the wheels 20 from the steering actuator 42. As a result, in the host vehicle 2 controlled to turn in the avoidance direction Da, the braking force Fb applied to the wheels 20 from the brake actuator 44 and the steering angle θs from the steering actuator 42 are cooperatively controlled according to the driving trajectory Td. As a result, even if a response delay in the steering angle θs of the steering actuator 42 and / or a response delay in the braking force Fb of the brake actuator 44 occurs, the turning control utilizing the front / rear allocation of the steering angle θs is quickly performed at a low-risk timing, and insufficient lateral movement of the host vehicle 2 under cooperative control can be eliminated. Therefore, the host vehicle 2 can be traced to the driving trajectory Td with high accuracy, ensuring a margin for collision avoidance, thereby enabling highly reliable driving assistance for the host vehicle 2 to avoid a collision with the target 3.

[0069] According to the second embodiment, the host vehicle 2 is controlled to turn in the avoidance direction Da by applying a steering angle θs that matches the avoidance direction Da, with the allocation limited to the rear wheels 20rl, 20rr. This allows the host vehicle 2 to be controlled to turn in the avoidance direction Da. Even if there is a response delay in the steering angle θs of the steering actuator 42 and / or a response delay in the braking force Fb of the braking actuator 44, turning control that concentrates the front / rear allocation of the steering angle θs on the rear wheels 20rl, 20rr can be performed while the risk is low, thereby increasing the amount of lateral movement. In particular, turning using the rear wheels 20rl, 20rr can increase the amount of lateral movement as much as possible even with a small steering angle θs, making it possible to achieve driving assistance that is effective in avoiding a collision with the target 3 in the host vehicle 2 and that provides peace of mind to the driver. Furthermore, in the host vehicle 2, which is configured to be able to disconnect the rear wheels 20rl, 20rr from the steering operation angle that determines the steering angle θs of the front wheels 20fl, 20fr, the steering operation angle can be essentially maintained to ensure a margin for collision avoidance, thereby making it possible to realize driving assistance that provides peace of mind to the driver.

[0070] Third Embodiment The third embodiment is a modification of the second embodiment. As shown in Fig. 8, in the driving assistance flow of the third embodiment, S3050 is executed instead of S2050. Therefore, in the third embodiment, the steering actuator 42 adjusts at least one of the common steering angle θs of the front wheels 20fl, 20fr and the common steering angle θs of the rear wheels 20rl, 20rr, similar to the first embodiment.

[0071] In detail below, in S3050, the driving control block 140 of the third embodiment generates a control command to the brake actuator 44 to control the attitude of the host vehicle 2 in the avoidance direction Da by allocating the steering angle θs applied to each wheel 20 of the host vehicle 2 between the front and rear wheels. At this time, the control command controlling the front-rear allocation of the common steering angle θs of the front wheels 20fl, 20fr and the common steering angle θs of the rear wheels 20rl, 20rr limits the allocation of the steering angle θs to the front wheels 20fl, 20fr to match the avoidance direction Da, thereby enabling turning with a slight actual yaw rate. Note that even in a host vehicle 2 configured without a mechanism for adjusting the common steering angle θs of the rear wheels 20rl, 20rr, this can be simulated as being equivalent to generating a control command that structurally sets the allocation of the steering angle θs to the rear wheels 20rl, 20rr to zero.

[0072] 9, when the avoidance direction Da is a left turning direction, a control command is generated to impart a counterclockwise common steering angle θs with a positive sign to the front wheels 20fl, 20fr, with a magnitude that keeps the difference between the required yaw rate Y_c, which is substantially zero, and the actual yaw rate according to the control command within a small allowable range. At this time, when the host vehicle 2 is in a driver override state through manual driving operation, the common steering angle θs of the front wheels 20fl, 20fr may be corrected within the range of the difference within the allowable range based on operation data from the operation judgment block 100. Furthermore, when the avoidance direction Da is a left turning direction, a control command is generated to impart a common steering angle θs of substantially zero to the rear wheels 20rl, 20rr.

[0073] When the avoidance direction Da is a right-turning direction, similar to the case of a left-turning direction, a control command is generated to impart a negative clockwise common steering angle θs to the front wheels 20fl, 20fr, with a magnitude that keeps the difference between the substantially zero requested yaw rate Y_c and the actual yaw rate based on the control command within a small tolerance range. At this time, if the host vehicle 2 is in a driver override state through manual driving operation, the common steering angle θs of the front wheels 20fl, 20fr may be corrected within the range of the difference within the tolerance range based on operation data from the operation judgment block 100. Furthermore, when the avoidance direction Da is a right-turning direction, similar to the case of a left-turning direction, a control command is generated to impart a substantially zero common steering angle θs to the rear wheels 20rl, 20rr.

[0074] (Operations and Effects) Operations and effects specific to the third embodiment described above will be described below.

[0075] According to the third embodiment, the host vehicle 2 is controlled to turn in the avoidance direction Da by applying a steering angle θs that matches the avoidance direction Da, with the steering angle θs allocated only to the front wheels 20fl, 20fr. This allows the host vehicle 2 to be controlled to turn in the avoidance direction Da. Even if there is a delay in the response of the steering actuator 42 in the steering angle θs and / or a delay in the response of the braking actuator 44 in the braking force Fb, it is possible to quickly perform turning control that concentrates the front and rear allocation of the steering angle θs on the front wheels 20fl, 20fr while the risk is low, thereby increasing the amount of lateral movement. Therefore, the host vehicle 2 can be made to trace the driving trajectory Td with high accuracy, ensuring a margin for collision avoidance, thereby enabling highly reliable driving assistance for the host vehicle 2 to avoid a collision with the target 3.

[0076] (Other Embodiments) Although multiple embodiments have been described above, the present disclosure should not be construed as being limited to those embodiments, and can be applied to various embodiments and combinations within the scope that does not deviate from the gist of the present disclosure.

[0077] In a modified example, the dedicated computer constituting the driving assistance system 1 may have at least one of a digital circuit and an analog circuit as a processor. Here, the digital circuit is at least one of an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a system on a chip (SOC), a programmable gate array (PGA), and a complex programmable logic device (CPLD). Furthermore, such a digital circuit may have a memory that stores a program.

[0078] In a modified example, the operator who manually drives the host vehicle 2 to which the driving assistance system 1 is applied may be a remote operator who remotely controls the driving of the host vehicle 2 from an external center. In a modified example, the driving assistance system 1 may be configured to be capable of realizing only automated driving tasks, without a manual driving assistance task that assists the operator in manual driving. During the pre-control period Pap of the modified example, the generation of control commands described in at least two of the first to third embodiments may be performed in combination.

[0079] (Additional Remarks) This specification discloses the following technical ideas and their combinations. Note that the reference symbols in parentheses in this Additional Remarks section indicate the correspondence with the specific means described in the above detailed embodiments, and do not limit the technical scope of the present disclosure.

[0080] (Technical Idea 1) A driving assistance system having a processor (12) that assists in avoiding a collision with a target (3) when driving a host vehicle (2), wherein the processor is configured to: turn control the host vehicle in an avoidance direction (Da) toward collision avoidance before a collision risk of the host vehicle with the target increases to a collision avoidance range that requires the host vehicle to avoid the collision; and cooperatively control a braking force (Fb) and a steering angle (θs) applied to wheels (20) from an actuator system (4) in accordance with a driving trajectory (Td) planned for the host vehicle toward collision avoidance in response to the collision risk reaching the collision avoidance range in the host vehicle that has been turned in the avoidance direction.

[0081] (Technical Idea 2) The driving assistance system according to Technical Idea 1, wherein the turning control of the host vehicle includes turning the host vehicle in the avoidance direction in response to the collision risk reaching a pre-avoidance range that is lower than the collision avoidance range.

[0082] (Technical Idea 3) A driving assistance system according to Technical Idea 1 or 2, wherein the turning control of the host vehicle includes controlling the turning of the host vehicle in the avoidance direction by distributing the braking force applied to the wheels from a braking actuator (44) to the left and right in the host vehicle, and the cooperative control of the host vehicle includes cooperatively controlling the steering angle and the braking force applied to the wheels from a steering actuator (42) in the host vehicle.

[0083] (Technical Idea 4) A driving assistance system according to Technical Idea 1 or 2, wherein the turning control of the host vehicle includes controlling the turning of the host vehicle in the avoidance direction by allocating the steering angle applied to the wheels from a steering actuator (42) in the host vehicle to the front and rear, and the cooperative control of the host vehicle includes cooperatively controlling the braking force applied to the wheels from a braking actuator (44) in the host vehicle and the steering angle.

[0084] (Technical Idea 5) A driving assistance system according to Technical Idea 4, wherein the turning control of the host vehicle includes controlling the host vehicle to turn in the avoidance direction by limiting the allocation to one of the rear wheels (20rl, 20rr) and the front wheels (20fl, 20fr) of the host vehicle and applying the steering angle in accordance with the avoidance direction.

[0085] (Technical Idea 6) A driving assistance system according to Technical Idea 5, wherein the turning control of the host vehicle includes controlling the host vehicle to turn in the avoidance direction by limiting the allocation to the rear wheels of the host vehicle and applying the steering angle in accordance with the avoidance direction.

[0086] (Technical Idea 7) A driving assistance system described in any one of Technical Ideas 1 to 6, wherein the turning control and the cooperative control of the host vehicle include performing averaging control that averages the maximum lateral movement amount (δL) that appears in the host vehicle between the left and right sides of the host vehicle during an avoidance control period (Pa) from the start of the turning control to the end of the cooperative control.

[0087] (Technical Concept 8) The driving assistance system according to Technical Concept 1 or 2, wherein the turning control of the host vehicle and the cooperative control are performed in a driver override state for the host vehicle.

[0088] The above-mentioned technical concepts 1 to 8 may be understood as the respective technical concepts of the program and method.

Claims

1. A driver assistance system having a processor (12) that assists in avoiding collisions with targets (3) during the operation of a host vehicle (2), The aforementioned processor, Before the risk of the host vehicle colliding with the target increases to the collision avoidance range that requires the host vehicle to avoid the collision, the host vehicle is controlled to turn in the avoidance direction (Da) toward collision avoidance, In the host vehicle, which is controlled to turn in the avoidance direction, the system is configured to coordinately control the braking force (Fb) and steering angle (θs) applied from the actuator system (4) to the wheels (20) in accordance with the driving trajectory (Td) planned for the host vehicle toward collision avoidance, in response to the collision risk reaching the collision avoidance range. The turning control of the host vehicle is as follows: This includes controlling the host vehicle to turn in the avoidance direction by limiting the distribution of the braking force applied to the wheels from the braking actuator (44) in the host vehicle to the left and right distribution, The coordinated control of the host vehicle is as follows: A driving assistance system that includes coordinating control of the steering angle applied to the wheels by the steering actuator (42) and the braking force in the host vehicle.

2. The turning control of the host vehicle is as follows: The driver assistance system according to claim 1, further comprising controlling the host vehicle to turn in the avoidance direction in response to the collision risk reaching a pre-avoidance range where the collision risk is lower than the collision avoidance range.

3. The turning control and the coordinated control of the host vehicle are as follows: The driving support system according to claim 1 or 2, further comprising performing an averaging control to average the maximum lateral movement amount (δL) that appears in the host vehicle during the avoidance control period (Pa) from the start of the turning control to the end of the cooperative control, on the left and right sides of the host vehicle.

4. A driving assistance program that is stored in a storage medium (10) to assist in avoiding collisions with targets (3) during the driving of a host vehicle (2), and includes instructions for causing a processor (12) to perform said assistance, Before the risk of the host vehicle colliding with the target increases to the collision avoidance range that requires the host vehicle to avoid the collision, the host vehicle is controlled to turn in the avoidance direction (Da) toward collision avoidance, The command includes causing the host vehicle, which is controlled to turn in the avoidance direction, to coordinately control the braking force (Fb) and steering angle (θs) applied from the actuator system (4) to the wheels (20) in accordance with the driving trajectory (Td) planned for the host vehicle toward collision avoidance, in response to the collision risk reaching the collision avoidance range, The turning control of the host vehicle is as follows: This includes controlling the host vehicle to turn in the avoidance direction by limiting the distribution of the braking force applied to the wheels from the braking actuator (44) in the host vehicle to the left and right distribution, The coordinated control of the host vehicle is as follows: A driving assistance program that includes coordinating control of the steering angle applied to the wheels by the steering actuator (42) in the host vehicle and the braking force.

5. A driving assistance method performed by a processor (12) to assist in avoiding collision with a target (3) during the operation of a host vehicle (2), Before the risk of the host vehicle colliding with the target increases to the collision avoidance range that requires the host vehicle to avoid the collision, the host vehicle is controlled to turn in the avoidance direction (Da) toward collision avoidance, This includes, in response to the collision risk reaching the collision avoidance range in the host vehicle which has been controlled to turn in the avoidance direction, coordinating the braking force (Fb) and steering angle (θs) applied from the actuator system (4) to the wheels (20) according to the driving trajectory (Td) planned for the host vehicle toward collision avoidance, The turning control of the host vehicle is as follows: This includes controlling the host vehicle to turn in the avoidance direction by limiting the distribution of the braking force applied to the wheels from the braking actuator (44) in the host vehicle to the left and right distribution, The coordinated control of the host vehicle is as follows: A driving assistance method that includes coordinating control of the steering angle applied to the wheels by the steering actuator (42) and the braking force in the host vehicle.