Driver assistance systems

Abstract

To provide a two-wheeled motor cycle driving support system that can avoid contact of the two-wheeled motor cycle with a pedestrian as much as possible.SOLUTION: A driving support system comprises: an external sensor unit that acquires forward information on a forward state of a vehicle body of a self vehicle serving as a two-wheeled motor cycle; and a driving support control device that calculates a relative speed and collision prediction time between the vehicle body and an object in front of the vehicle on the basis of the acquired forward information, and further implements emergency avoidance-purpose brake control automatically operating a brake device at a timing determined based on the collision prediction time. When an object is a pedestrian, the driving support control device implements the emergency avoidance-purpose brake control when a current state point to be identified by the relative speed and the collision prediction time falls within an area 1 higher than a braking avoidance limit line L4, and implements emergency avoidance-purpose steering control automatically changing an advancement direction of the vehicle body when the state point falls within an area 2 equal to or less than the braking avoidance limit line L4.SELECTED DRAWING: Figure 16

Description

[Technical Field]

[0001] The present invention relates to a driving assistance system, and more particularly to a driving assistance system for a motorcycle that has a function of automatically operating a brake device based on forward information and a predicted collision time. [Background technology]

[0002] In recent years, many four-wheeled passenger vehicles have been equipped with collision mitigation braking systems (hereinafter also referred to as "AEB systems") in order to improve traffic safety. An AEB system is a system that automatically operates the braking device in order to avoid a collision between the vehicle and an obstacle or to reduce the collision speed. In the case of motorcycles, AEB systems can also reduce collision damage by reducing the collision speed, and therefore research into installing AEB systems on motorcycles has been progressing in recent years (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-2328 Summary of the Invention [Problem to be solved by the invention]

[0004] In this way, conventional AEB devices can reduce the collision speed before contact with the target, so even if the driver is unable to stop the vehicle before the predicted collision point where contact with the target is predicted due to a delay in recognizing the target, damage to both the vehicle and the target can be reduced. However, if the target is a pedestrian, it is preferable to avoid contact between the two as much as possible.

[0005] An object of the present invention is to provide a motorcycle driving assistance system that can avoid contact between a motorcycle and a pedestrian as much as possible. [Means for solving the problem]

[0006] (1) The driving assistance system of the present invention comprises a forward information acquisition means for acquiring forward information regarding the condition ahead of the vehicle body, which is a motorcycle; a prediction means for calculating the relative speed and predicted collision time between the vehicle body and an object ahead of the vehicle body based on the forward information; and a driving assistance control means for executing automatic braking control that automatically operates a brake device at a timing determined based on the predicted collision time, wherein, when the object is a pedestrian, the driving assistance control means executes the automatic braking control when the relative speed is less than a speed threshold determined based on the predicted collision time, and executes direction change control that automatically changes the direction of travel of the vehicle body when the relative speed is equal to or greater than the speed threshold.

[0007] (2) In this case, it is preferable that the driving assistance control means sets the speed threshold to a smaller value as the collision prediction time becomes shorter.

[0008] (3) In this case, it is preferable that the driving assistance control means executes the travel direction change control and changes the travel direction of the vehicle body to the avoidance space when the relative speed is equal to or greater than the speed threshold and there is an avoidance space in which at least one obstacle is not present near the target, and executes the automatic braking control when the relative speed is equal to or greater than the speed threshold and there is no avoidance space.

[0009] (4) In this case, it is preferable that the driving assistance control means determines whether or not the avoidance space exists within the lane in which the host vehicle is traveling or within the roadway excluding the sidewalk.

[0010] (5) In this case, when the object is a pedestrian crossing the roadway, it is preferable that the driving assistance control means determines whether or not the avoidance space exists by prioritizing the rear side of the object's direction of movement over the front side of the object's direction of movement.

[0011] (6) In this case, it is preferable that the prediction means calculates the relative speed and the collision prediction time after the start-up time of the automatic braking control from the time when it is determined that the collision prediction time is equal to or less than a predetermined first time threshold as an estimated relative speed and an estimated collision prediction time, respectively, and that the driving assistance control means executes the automatic braking control when the estimated relative speed is less than the speed threshold determined based on the estimated collision prediction time, and executes the direction change control when the estimated relative speed is equal to or greater than the speed threshold.

[0012] (7) In this case, when the collision prediction time is equal to or less than a second time threshold set greater than the first time threshold, it is preferable that the driving assistance control means automatically operates the brake device to perform warning braking that vibrates the vehicle body by intermittently generating braking force.

[0013] (8) In this case, it is preferable that the driving assistance control means executes the travel direction change control to avoid contact with the object, and then executes a post-avoidance assistance process to decelerate the vehicle body while keeping it upright by automatically operating the brake device and steering device.

[0014] (9) The driving assistance system of the present invention comprises a forward information acquisition means for acquiring forward information regarding the condition ahead of the vehicle body, which is a motorcycle; a prediction means for calculating the relative speed and predicted collision time between the vehicle body and an object ahead of the vehicle body based on the forward information; and a driving assistance control means for executing automatic braking control that automatically operates a brake device at a timing determined based on the predicted collision time, wherein, when the object is a pedestrian, the driving assistance control means executes the automatic braking control when the predicted collision time is greater than a time threshold determined based on the relative speed, and executes direction change control that automatically controls the direction of travel of the vehicle body when the predicted collision time is equal to or less than the time threshold.

[0015] (10) In this case, it is preferable that the driving assistance control means sets the time threshold to a smaller value as the relative speed decreases. [Effects of the Invention]

[0016] (1) In the driving assistance system according to the present invention, the driving assistance control means executes automatic braking control, which automatically operates the brake device at a timing determined based on the collision prediction time calculated by the prediction means. Here, when the target is a pedestrian, the driving assistance control means executes automatic braking control when the relative speed calculated by the prediction means is less than a speed threshold determined based on the collision prediction time, and executes direction change control, which automatically changes the traveling direction of the vehicle body when the relative speed is equal to or greater than the speed threshold. Therefore, according to the present invention, when the relative speed is less than the speed threshold and contact with the target can be avoided by automatic braking control, automatic braking control, which reduces the risk of the host vehicle tipping over, is executed, thereby avoiding contact between the host vehicle and the target and preventing damage caused by tipping over of the host vehicle. Furthermore, when the relative speed is equal to or greater than the speed threshold and contact with the target cannot be avoided by automatic braking control, direction change control is executed, thereby avoiding contact between the host vehicle and the target. Therefore, according to the present invention, by switching between automatic braking control and direction change control depending on the relative speed with respect to the target and the collision prediction time, contact between the host vehicle and the pedestrian target can be avoided as much as possible, thereby improving traffic safety.

[0017] (2) By setting the speed threshold to a smaller value as the collision prediction time becomes shorter, the driving assistance control means can appropriately distinguish between cases where contact can be avoided by automatic braking control and cases where contact can be avoided by direction change control, thereby making it possible to avoid contact between pedestrians and the vehicle as much as possible.

[0018] (3) The driving assistance control means changes the traveling direction of the vehicle body to the avoidance space by executing a traveling direction change control when the relative speed is equal to or greater than the speed threshold and there is an avoidance space where at least one obstacle is not present near the target, and executes an automatic braking control when the relative speed is equal to or greater than the speed threshold and there is no avoidance space. This makes it possible to prevent the vehicle body from coming into contact with an obstacle after changing the traveling direction of the vehicle body to avoid contact with the target, thereby further improving traffic safety.

[0019] (4) The driving assistance control means determines whether or not there is an avoidance space within the roadway excluding the vehicle's lane or the sidewalk. This prevents the vehicle from colliding with another moving object in an adjacent lane or running onto the sidewalk after changing the direction of travel of the vehicle to avoid contact with an object, thereby further improving traffic safety.

[0020] (5) When the target is a pedestrian crossing the roadway, the driving assistance control means determines whether there is an avoidance space behind the target rather than ahead of it in the direction of travel. This makes it possible to more reliably avoid contact between the vehicle and the target, further improving traffic safety.

[0021] (6) The prediction means calculates the relative speed and the collision prediction time from the time when it is determined that the collision prediction time is equal to or less than the first time threshold until the automatic braking control starts up time as an estimated relative speed and an estimated collision prediction time, respectively, and the driving assistance control means executes automatic braking control when the estimated relative speed is less than the speed threshold determined based on the estimated collision prediction time, and executes directional change control when the estimated relative speed is equal to or greater than the speed threshold. Therefore, according to the present invention, when the collision prediction time becomes equal to or less than the first time threshold, it is possible to appropriately determine whether automatic braking control or directional change control should be executed, taking into account the time it takes for automatic braking control to start up, thereby making it possible to avoid contact between the host vehicle and an object as much as possible, and ultimately to further improve traffic safety.

[0022] (7) When the collision prediction time is equal to or less than a second time threshold set greater than the first time threshold, i.e., before executing automatic braking control or direction change control, the driving assistance control means automatically operates the brake device to generate braking force intermittently, thereby executing warning braking that vibrates the vehicle body and ultimately parts of the rider's body that are in contact with the vehicle body. This makes it possible to reliably make the presence of an object known to, for example, a rider who is not looking at the display or a rider who is wearing a full-face helmet and has difficulty hearing the warning sound before starting automatic braking control or direction change control, thereby making it possible to avoid contact between the vehicle and the object as much as possible, and ultimately to further improve traffic safety.

[0023] (8) The driving assistance control means executes a travel direction change control to avoid contact with the object, and then executes a post-avoidance assistance process to automatically operate the brake device and steering device to decelerate the vehicle body while keeping it upright. This makes it possible to avoid both contact between the vehicle and the object and the vehicle tipping over, thereby further improving traffic safety.

[0024] (9) The driving assistance system according to the present invention has the same effects as the invention according to (1) above.

[0025] (10) The driving assistance system according to the present invention has the same effects as the invention according to (2) above. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a diagram schematically illustrating a configuration of a driving assistance system according to an embodiment of the present invention. [Figure 2] 10A and 10B are diagrams for explaining a procedure for determining an avoidance space by an avoidance space determination unit. [Figure 3] 10A and 10B are diagrams for explaining a procedure for determining an avoidance space by an avoidance space determination unit. [Figure 4]4 is a flowchart showing a specific procedure for emergency braking control by the driving assistance control device (from recognition of an object to start of emergency avoidance braking control or emergency avoidance steering control). [Figure 5] 4 is a flowchart showing a specific procedure for emergency braking control by the driving assistance control device (from recognition of an object to start of emergency avoidance braking control or emergency avoidance steering control). [Figure 6] 4 is a flowchart showing a specific procedure for emergency braking control by the driving assistance control device (processing for determining whether steering avoidance control is to be performed). [Figure 7] 4 is a flowchart showing a specific procedure of emergency braking control by the driving assistance control device (after the start of emergency avoidance braking control). [Figure 8] 4 is a flowchart showing a specific procedure for emergency braking control by the driving assistance control device (emergency avoidance steering control). [Figure 9] 4 is a flowchart showing a specific procedure for emergency braking control by the driving assistance control device (emergency avoidance steering control). [Figure 10] 4 is a flowchart showing a specific procedure for emergency braking control by the driving assistance control device (post-avoidance assistance processing). [Figure 11] 4 is a flowchart showing a specific procedure for emergency braking control by the driving assistance control device (post-avoidance assistance processing). [Figure 12] 4 is a flowchart showing a specific procedure for emergency braking control by the driving assistance control device (post-avoidance assistance processing). [Figure 13] 4 is a flowchart showing a specific procedure for emergency braking control by the driving assistance control device (post-avoidance assistance processing). [Figure 14] 4 is a flowchart showing a specific procedure for emergency braking control by the driving assistance control device (post-avoidance assistance processing). [Figure 15] 4 is a flowchart showing a specific procedure for emergency braking control by the driving assistance control device (post-avoidance assistance processing). [Figure 16]FIG. 10 is a diagram showing an example of a map showing a warning judgment line, a warning braking judgment line, a collision possibility judgment line, a braking avoidance limit line, and a steering avoidance limit line. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, the configuration of a driving assistance system according to an embodiment of the present invention will be described with reference to the drawings.

[0028] FIG. 1 is a diagram showing the configuration of a driving assistance system 1 according to this embodiment. The driving assistance system 1 is mounted on a motorcycle (not shown). The driving source of the motorcycle may be an internal combustion engine, a rotating electric machine, or a combination of these. The power source for the rotating electric machine may be a secondary battery, a capacitor, or a fuel cell.

[0029] The driving assistance system 1 assists the driver in safe driving of a motorcycle. Among the various driving assistance functions realized by this driving assistance system 1, the following describes an emergency braking function that automatically operates the brake device to avoid a collision between the vehicle body of the vehicle (hereinafter simply referred to as "vehicle body") and an object or to mitigate damage from the collision.

[0030] The driving assistance system 1 includes an external sensor unit 2, a vehicle sensor unit 3, a human machine interface 4 (hereinafter abbreviated as "HMI4"), an emergency notification device 5, a driving assistance control device 6, a driving operator 81, a driving force output device 82, a braking device 83, and a rear wheel rocking mechanism 84. These devices are connected to each other by multiplexed communication lines such as a CAN (Controller Area Network) communication line, serial communication lines, a wireless communication network, etc.

[0031] The external sensor unit 2 is composed of a front sensor unit 21, a rear sensor unit 22, an external recognition device 24, and the like.

[0032] The front sensor unit 21 is configured with a digital camera using a solid-state image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) provided at the front of the vehicle, a millimeter wave radar that detects an object by measuring the wave reflected from the object when irradiated with millimeter waves, etc. The digital camera and millimeter wave radar that configure the front sensor unit 21 are attached to any position on the front of the vehicle, such as the front windshield or mirror, with each facing forward.

[0033] The rear sensor unit 22 is configured with a digital camera, millimeter-wave radar, etc., provided at the rear of the vehicle body. The digital camera and millimeter-wave radar that make up the rear sensor unit 22 are provided at any position on either side of the rear of the vehicle body, such as near the left and right turn signals or near the tail lamps, while facing toward the left and right rear sides of the vehicle body.

[0034] The external recognition device 24 is a computer that performs sensor fusion processing on the detection results from some or all of the front sensor unit 21 and the rear sensor unit 22 to acquire information about the state in front of the vehicle body, more specifically, information about the position, shape, type, and speed of roads and objects in front of the vehicle body, as well as information about road signs (hereinafter, these will be collectively referred to as "front information"), and information about the state behind the vehicle body (including the rear, left rear, and right rear of the vehicle body), more specifically, information about the position, shape, type, and speed of roads and objects behind the vehicle body (hereinafter, these will be collectively referred to as "rear-side information"). The external recognition device 24 transmits the acquired front information and rear-side information to, for example, the driving assistance control device 6.

[0035] The vehicle sensor unit 3 includes a vehicle speed sensor 31 that detects the vehicle speed, a five-axis or six-axis inertial measurement unit 32, etc. The inertial measurement unit 32 detects the angles or angular velocities and accelerations of three axes (roll axis, pitch axis, and yaw axis) of the vehicle body. The detection signals of the vehicle sensor unit 3 are transmitted to, for example, the driving assistance control device 6.

[0036] The HMI 4 is composed of multiple interfaces that present various information to the vehicle occupants and accept input operations by the occupants. Of the multiple interfaces that make up the HMI 4, only the display 41 and speaker 42, which are particularly related to the emergency braking function, are shown in Figure 1.

[0037] The display 41 is provided in a position visible to the rider while driving, and displays images and messages in response to commands from a warning control unit 66 (described later) of the driving assistance control device 6. The speaker 42 issues warning sounds and messages in response to commands from the warning control unit 66.

[0038] The emergency notification device 5 makes an emergency notification to an emergency notification center (not shown) by wireless communication based on a command from an emergency notification control unit 65 (described later) of the driving assistance control device 6.

[0039] The driving operators 81 include an accelerator grip and brake lever that the rider operates when accelerating or decelerating, a clutch lever and shift pedal that the rider operates when shifting gears, a steering handle that the rider operates when turning, and multiple operator sensors that detect the amount of operation of these and whether or not they are operated. Detection signals from these operator sensors are sent to the driving assistance control device 6.

[0040] The driving force output device 82 outputs a driving force to the driving wheels for driving the vehicle. The driving force output device 82 includes a driving force source such as an internal combustion engine or a rotating electric machine, a transmission, and an electronic control unit that controls the driving force source and the transmission based on command signals sent from the driving assistance control device 6 and generates acceleration / deceleration according to the commands.

[0041] The braking device 83 includes, for example, a brake caliper, a cylinder that transmits hydraulic pressure to the brake caliper in accordance with the amount of operation of the brake lever or brake pedal, an electric motor that generates hydraulic pressure in the cylinder, and an electronic control unit that controls the electric motor based on a command signal sent from the driving assistance control device 6 and generates braking force in accordance with the command.

[0042] The rear wheel rocking mechanism 84 changes the position of the center of gravity of the vehicle along the vehicle width direction by rocking the orientation of the rotation axis of the rear wheel relative to the vehicle body based on a command signal transmitted from a later-described attitude control unit 64 of the driving assistance control device 6. Note that the detailed configuration of this rear wheel rocking mechanism 84 is described in Japanese Patent Application Laid-Open Nos. 2021-175638 and 2021-175639 by the applicant of the present application, and therefore detailed description thereof will be omitted.

[0043] The steering device 85 changes the direction of the front wheels in response to the operation of the steering wheel by the driver. The steering device 85 also includes an actuator that changes the direction of the front wheels in response to an input from an automatic steering control unit 62, which will be described later.

[0044] The driving assistance control device 6 is a computer that is responsible for controlling the driving assistance functions. The driving assistance control device 6 includes a prediction control unit 60, an automatic braking control unit 61, an automatic steering control unit 62, an avoidance space determination unit 63, an attitude control unit 64, an emergency call control unit 65, and an alarm control unit 66 as modules that realize the emergency braking function among the multiple driving assistance functions.

[0045] Based on the forward information acquired by the external sensor unit 2, the prediction control unit 60 identifies moving objects, obstacles, etc. in front of the vehicle body that may come into contact with the vehicle body in the near future, and calculates parameters such as the predicted course of the vehicle, the position of the object, direction of travel, movement speed, and relative speed between the object and the vehicle body, and based on these parameters, calculates the predicted collision point, which is the point where the object is predicted to collide with the vehicle body, and the predicted collision time, which is the time it is predicted will be until the object and the vehicle body collide.

[0046] The automatic braking control unit 61 executes automatic braking control to automatically operate the brake device 83 in response to a predetermined condition being satisfied, thereby decelerating the vehicle body. In particular, when the current state point identified by the relative speed and collision prediction time calculated by the prediction control unit 60 is within a region below a collision possibility judgment line L3 (see FIG. 16 described below), the automatic braking control unit 61 executes automatic braking control to automatically operate the brake device 83 so that the vehicle body stops before the collision prediction point and contact between the object and the vehicle body is avoided. Note that, hereinafter, the automatic braking control executed in response to a determination that the state point is within a region below the collision possibility judgment line L3 is also referred to as emergency avoidance braking control.

[0047] The automatic steering control unit 62 executes automatic steering control, which automatically operates the steering device 85 and changes the direction of the front wheels when a predetermined condition is satisfied, thereby automatically changing the traveling direction of the vehicle body and keeping the vehicle body upright. In particular, similar to the automatic braking control unit 61, when the current state point specified by the relative speed and collision prediction time is within the area below the collision possibility judgment line L3, the automatic steering control unit 62 executes automatic steering control, which automatically operates the steering device 85 so as to change the traveling direction of the vehicle body toward an avoidance space determined by an avoidance space determination unit 63, which will be described later. Note that hereinafter, automatic steering control for changing the traveling direction of the vehicle body to the avoidance space determined by the avoidance space determination unit 63 in this way is also particularly referred to as emergency avoidance steering control. Note that this automatic steering control by the automatic steering control unit 62 may be executed in combination with automatic attitude control, which will be described later, in order to prevent the vehicle body from tipping over by automatically changing the traveling direction of the vehicle body.

[0048] The avoidance space determination unit 63 determines an avoidance space that determines the traveling direction of the body of the host vehicle when executing emergency avoidance steering control for a pedestrian. When it is determined that the current state point specified by the relative speed and collision prediction time calculated for the pedestrian is within an area below the collision possibility determination line L3, the avoidance space determination unit 63 extracts, as an avoidable area, an area that is near the object and does not contain at least an obstacle that will hinder the traveling of the host vehicle, based on forward information acquired by the external sensor unit 2, and determines, from the extracted multiple avoidable areas, the area that is most suitable for avoiding contact with the object as the avoidance space.

[0049] An example of a procedure for determining the avoidance space by the avoidance space determining unit 63 will now be described with reference to FIGS.

[0050] Fig. 2 is a plan view of the roadway 9 at the time when it is determined that the state point (relative speed and predicted collision time) calculated for a pedestrian attempting to cross the roadway 9 from left to right as viewed from a motorcycle is within the area below the collision possibility judgment line L3. In Fig. 2, the predicted collision point 9a, i.e., the point where the pedestrian is predicted to be present after the predicted collision time from the time shown in Fig. 2, is indicated by a dashed line. Fig. 3 is a plan view of the roadway 9 from the time shown in Fig. 2 to the predicted collision time.

[0051] First, the avoidance space determination unit 63 extracts, as an avoidable area, an area within the vehicle's travel lane or the roadway (excluding the sidewalk) that excludes the predicted collision point 9a and points where obstacles that may obstruct the travel of the vehicle are present and that is wider than the body of the vehicle. In other words, the avoidance space determination unit 63 does not determine an avoidance space outside the vehicle's travel lane (i.e., a travel lane adjacent to the vehicle's travel lane), on the sidewalk, within the predicted collision point, or within points where obstacles are present. In addition, in this case, it is preferable that the avoidance space determination unit 63 extracts, as an avoidable area, an area that is a predetermined margin distance away from the predicted collision point 9a on both sides of the vehicle width direction. Here, it is preferable that the margin distance determined with the predicted collision point 9a as the base point be set longer on the front side of the target's movement direction (in the example of FIG. 2, the right side as viewed from the motorcycle) than on the rear side of the target's movement direction (in the example of FIG. 2, the left side as viewed from the motorcycle).

[0052] For this reason, in the example shown in FIG. 2, the avoidance space determination unit 63 extracts two areas as avoidable areas: a first avoidable area 9b to the left of the predicted collision point 9a as seen from the motorcycle; and a second avoidable area 9c to the right of the predicted collision point 9a as seen from the motorcycle. When multiple avoidable areas 9b, 9c are extracted in this manner, the avoidance space determination unit 63 determines, as the avoidance space, the area that is most suitable for avoiding contact with the object from among these multiple avoidable areas 9b, 9c. As shown in FIG. 2, if the object is a crossing pedestrian, the first avoidable area 9b, which is located behind the object in the direction of movement, has a lower risk of contact than the second avoidable area 9c, which is located ahead of the object in the direction of movement. For this reason, in the example shown in FIG. 2, the avoidance space determination unit 63 prioritizes the first avoidable area 9b over the second avoidable area 9c when determining the avoidance space. Furthermore, by executing emergency avoidance steering control to change the direction of travel of the vehicle body toward the avoidance space determined in this manner, it is possible to avoid contact between the motorcycle and the object after the collision prediction time, as shown in Figure 3.

[0053] When multiple avoidable areas are extracted as described above, the avoidance space determination unit 63 determines an avoidance space so as to reduce not only the risk of contact with the target, but also the risk of contact with moving objects other than the target and the risk of the vehicle tipping over, by taking into consideration the direction of movement of pedestrians as described above, as well as the size of each avoidable area, the distance between each avoidable area and the sidewalk, the amount of steering control required to change the direction of travel of the vehicle to each avoidable area, the presence of other moving objects, pedestrians, and obstacles in the vicinity of each avoidable area, and the position of following vehicles.

[0054] More specifically, when two avoidable areas of different sizes are extracted, the avoidance space determination unit 63 determines the wider avoidable area as the avoidance space with priority over the narrower avoidable area. Also, when two avoidable areas of different distances from the sidewalk are extracted, the avoidance space determination unit 63 determines the avoidable area that is farther from the sidewalk with priority over the avoidable area that is closer to the sidewalk with priority over the avoidable area that is closer to the sidewalk. Therefore, when two avoidable areas of the same size are extracted, the avoidance space determination unit 63 determines the one that is farther from the sidewalk as the avoidance space.

[0055] 1, when a predetermined condition is satisfied, the attitude control unit 64 automatically operates the rear wheel rocking mechanism 84 to change the position of the center of gravity of the vehicle along the vehicle width direction, thereby performing automatic attitude control to automatically control the attitude of the vehicle body. Note that the specific procedure for this automatic attitude control is described in Japanese Patent Application Laid-Open Nos. 2021-175638 and 2021-175639 by the applicant of the present application, and therefore a detailed description thereof will be omitted.

[0056] The emergency call control unit 65 makes an emergency call to the emergency call center using the emergency call device 5 when a predetermined condition is satisfied.

[0057] When a predetermined condition is satisfied, the warning control unit 66 issues a warning using, for example, a horn to an object that may come into contact with the body of the vehicle. Furthermore, when a predetermined condition is satisfied, the warning control unit 66 automatically and intermittently operates the brake device 83 to issue a warning brake that vibrates the body of the vehicle and, ultimately, a part of the rider's body that is in contact with the body.

[0058] 4 to 15 are flowcharts showing specific steps of emergency braking control by the driving assistance control device 6. Note that, below, the emergency braking function that operates particularly for pedestrians will be described in detail. That is, a description of the emergency braking function that operates for bicycles, four-wheeled vehicles, etc. will be omitted. The processing shown in FIGS. 4 to 15 is repeatedly executed by the driving assistance control device 6 in a predetermined control cycle after the rider turns on a main switch (not shown) to start the driving assistance system 1. Note that each step shown in FIGS. 4 to 15 is realized by the driving assistance control device 6 executing a computer program stored in a storage device (not shown) while the driving assistance system 1 is running.

[0059] 4 and 5 are flowcharts showing the procedure in emergency braking control from when an object is recognized to when either emergency avoidance braking control or steering avoidance control for this object is started.

[0060] First, in step ST1, the driving assistance control device 6 acquires forward information from the external sensor unit 2 and proceeds to step ST2. In step ST2, the driving assistance control device 6 determines whether or not a pedestrian has been recognized in front of the vehicle based on the forward information acquired in step ST1. If the determination result in step ST2 is YES, the driving assistance control device 6 proceeds to step ST3, and if the determination result is NO, the driving assistance control device 6 returns to step ST1.

[0061] In step ST3, the driving assistance control device 6 calculates the position, traveling direction, and moving speed of the pedestrian recognized in step ST2, and the relative speed between the pedestrian and the vehicle, based on the forward information and the vehicle speed, and then proceeds to step ST4. In step ST4, the driving assistance control device 6 calculates the predicted course of the vehicle based on the steering angle, and then proceeds to step ST5.

[0062] In step ST5, the driving assistance control device 6 determines, based on the forward information acquired in step ST1 and the information calculated in step ST3, whether the pedestrian recognized in step ST2 has entered or is about to enter the predicted path of the vehicle calculated in step ST4. If the determination result in step ST5 is YES, the driving assistance control device 6 proceeds to step ST6, and if the determination result is NO, the driving assistance control device 6 returns to step ST1. Note that, hereinafter, the pedestrian recognized in step ST5 will also be simply referred to as the "target."

[0063] In step ST6, the driving assistance control device 6 calculates the collision prediction time, which is the time it is predicted to take for the object to collide with the vehicle body, based on the position, direction of travel, moving speed, and relative speed of the object calculated in step ST3, and the predicted course of the vehicle calculated in step ST4, and then proceeds to step ST7.

[0064] In step ST7, the driving assistance control device 6 determines whether it is time to issue a warning to the target based on the relative speed between the target and the vehicle and the predicted collision time. More specifically, the driving assistance control device 6 determines whether it is time to issue a warning to the target by determining whether the current state point specified by the current relative speed and the predicted collision time is within an area below a warning determination line L1 (i.e., an area shorter along the collision prediction time axis than the warning determination line L1) defined on a state map (see FIG. 16) with the relative speed on the horizontal axis and the predicted collision time on the vertical axis. If the determination result in step ST7 is YES, the driving assistance control device 6 proceeds to step ST8, and if the determination result is NO, the driving assistance control device 6 returns to step ST1.

[0065] In step ST8, the driving assistance control device 6 issues a warning to the pedestrian target, and then proceeds to step ST9. Here, the warning to the target is, for example, the generation of a warning sound using a horn.

[0066] In step ST9, the driving assistance control device 6 determines whether it is time to perform warning braking based on the relative speed between the target and the vehicle and the collision prediction time. More specifically, the driving assistance control device 6 determines whether it is time to perform warning braking by determining whether the current state point identified by the current relative speed and the collision prediction time is within an area below the warning braking judgment line L2 defined on the state map illustrated in FIG. 16 (i.e., an area shorter along the collision prediction time axis than the warning braking judgment line L2). Note that, as shown in FIG. 16, this warning braking judgment line L2 is defined on the state map below the above-mentioned warning judgment line L1 and slightly above the collision possibility judgment line L3 described below. Note that in this embodiment, the warning braking judgment line L2 is described as being constant with respect to the relative speed, for example, as shown in FIG. 16, i.e., the warning braking judgment line L2 is defined as a threshold for the collision prediction time (hereinafter also referred to as the "warning braking judgment time threshold"). However, the present invention is not limited to this. Therefore, in step ST9, the driving assistance control device 6 determines whether the time has come to perform warning braking by determining whether the current collision prediction time is equal to or less than the warning braking determination time threshold. If the determination result in step ST9 is YES, the driving assistance control device 6 proceeds to step ST10, and if the determination result is NO, the driving assistance control device 6 returns to step ST1.

[0067] In step ST10, the driving assistance control device 6 executes warning braking and proceeds to step ST11. In step ST11, the driving assistance control device 6 determines whether it is time to perform emergency avoidance braking control or emergency avoidance steering control. More specifically, the driving assistance control device 6 determines whether it is time to perform emergency avoidance braking control or emergency avoidance steering control by determining whether the current state point specified by the current relative speed and the collision prediction time is within an area equal to or less than a collision possibility determination line L3 defined on the state map illustrated in FIG. 16 (i.e., an area shorter along the collision prediction time axis than the collision possibility determination line L3). Note that in this embodiment, a case will be described in which the collision possibility determination line L3 is constant with respect to the relative speed, for example, as shown in FIG. 16, that is, a case in which the collision possibility determination line L3 is defined as a threshold for the collision prediction time (hereinafter also referred to as a "collision possibility determination time threshold"); however, the present invention is not limited to this. Therefore, in step ST11, the driving assistance control device 6 determines whether the time has come to perform emergency avoidance braking control or emergency avoidance steering control by determining whether the current collision prediction time is equal to or less than the collision possibility judgment time threshold.

[0068] In addition, the collision possibility determination line L3 is set in a region above the limit at which contact with the object can be avoided when emergency avoidance steering control is performed (i.e., a steering avoidance limit line L5 described later). If the determination result of step ST11 is YES, the driving assistance control device 6 proceeds to step ST12 (see FIG. 5), and if the determination result is NO, the driving assistance control device 6 returns to step ST1.

[0069] As shown in Fig. 5, in step ST12, the driving assistance control device 6 determines whether or not the current state point specified by the current relative speed and the collision prediction time is within an area equal to or less than the braking avoidance limit line L4 defined on the state map illustrated in Fig. 16 (i.e., an area shorter than the braking avoidance limit line L4 along the collision prediction time axis). Here, the braking avoidance limit line L4 is a line obtained by plotting the limit state point at which contact with the object can be avoided when emergency avoidance braking control is executed. Therefore, it can be said that determining whether or not the current state point is within an area equal to or less than the braking avoidance limit line L4 is equivalent to determining whether or not contact with the object can be avoided when emergency avoidance braking control is executed from the present time.

[0070] 16, the relative speed on such a braking-avoidance limit line L4 decreases as the collision prediction time decreases. In other words, if this braking-avoidance limit line L4 is defined as a speed threshold for the relative speed, the speed threshold is set to a smaller value as the collision prediction time decreases. Therefore, in step ST12, the driving assistance control device 6 can determine whether the current state point is within the area below the braking-avoidance limit line L4 by determining whether the current relative speed is equal to or greater than the speed threshold determined based on the current collision prediction time.

[0071] 16, the collision prediction time on the braking avoidance limit line L4 becomes shorter as the relative speed becomes lower. In other words, if this braking avoidance limit line L4 is defined as a time threshold for the collision prediction time, this time threshold is set to a smaller value as the relative speed becomes lower. Therefore, in step ST12, the driving assistance control device 6 can also determine whether the current state point is within the area below the braking avoidance limit line L4 by determining whether the current collision prediction time is equal to or less than the time threshold determined based on the current relative speed.

[0072] If the determination result in step ST12 is YES, that is, if it is determined that there is a possibility that contact with the object cannot be avoided even if emergency avoidance braking control is started from the current time, the driving assistance control device 6 proceeds to step ST13. On the other hand, if the determination result in step ST12 is NO, that is, if it is determined that there is a high possibility that contact with the object can be avoided if emergency avoidance braking control is started from the current time, the driving assistance control device 6 proceeds to step ST18.

[0073] In step ST13, the driving assistance control device 6 determines whether or not the current state point specified by the current relative speed and the collision prediction time is within an area equal to or less than the steering avoidance limit line L5 defined on the state map illustrated in FIG. 16 (i.e., an area shorter than the steering avoidance limit line L5 along the collision prediction time axis). Here, the steering avoidance limit line L5 is a line obtained by plotting the limit state point at which contact with the object can be avoided when emergency avoidance steering control is executed. Therefore, it can be said that determining whether or not the current state point is within an area equal to or less than the steering avoidance limit line L5 is equivalent to determining whether or not contact with the object can be avoided when emergency avoidance steering control is executed from the present time.

[0074] Note that in this embodiment, the steering avoidance limit line L5 is assumed to be constant with respect to the relative speed as shown in Fig. 16, for example, that is, the steering avoidance limit line L5 is defined as a threshold value for the collision prediction time (hereinafter also referred to as "steering avoidance limit time threshold"), but the present invention is not limited to this. Therefore, in step ST13, the driving assistance control device 6 determines whether the current collision prediction time is equal to or less than the steering avoidance limit time threshold, thereby determining whether the current state point is within the area equal to or less than the steering avoidance limit line L5.

[0075] 16, the steering avoidance limit line L5 is located closer to the collision prediction time axis than the braking avoidance limit line L4 in areas where the relative speed is high, and is located farther to the collision prediction time axis than the braking avoidance limit line L4 in areas where the relative speed is low. Therefore, the area below the collision possibility judgment line L3 is divided into area 1 between the collision possibility judgment line L3 and the braking avoidance limit line L4, area 2 between the collision possibility judgment line L3, the braking avoidance limit line L4, and the steering avoidance limit line L5, and area 3 below the braking avoidance limit line L4 and the steering avoidance limit line L5.

[0076] Region 1 is a region where there is a high possibility that contact with the object can be avoided by at least executing emergency avoidance braking control. Region 2 is a region where there is a possibility that contact with the object cannot be avoided even if emergency avoidance braking control is executed, but there is a high possibility that contact with the object can be avoided by executing emergency avoidance steering control. Region 3 is a region where there is a possibility that contact with the object cannot be avoided by executing either emergency avoidance braking control or emergency avoidance steering control.

[0077] If the determination result in step ST13 is YES, that is, if it is determined that there is a possibility that contact with the object cannot be avoided even if emergency avoidance braking control or emergency avoidance steering control is started from the current point in time, the driving assistance control device 6 proceeds to step ST14. On the other hand, if the determination result in step ST12 is NO, that is, if it is determined that there is a high possibility that contact with the object can be avoided if emergency avoidance braking control is started from the current point in time, the driving assistance control device 6 proceeds to step ST18.

[0078] In step ST14, the driving assistance control device 6 starts emergency avoidance braking control in response to the determination that the current state point is within region 3, and proceeds to step ST51 (see FIG. 7). Here, when starting emergency avoidance braking control, the driving assistance control device 6 preferably gradually changes the control amount (e.g., brake operation amount) in the automatic braking control over an automatic braking control rise time determined according to the current state of the vehicle body (e.g., vehicle speed, acceleration, etc.), in order to prevent the vehicle body behavior from becoming unstable.

[0079] In step ST15, the driving assistance control device 6 executes a steering avoidance control execution determination process to determine whether or not emergency avoidance steering control can be executed in response to the determination that the current state point is within region 2, and then proceeds to step ST16. Note that the specific procedure of this steering avoidance control execution determination process will be described later with reference to FIG.

[0080] In step ST16, the driving assistance control device 6 determines whether or not emergency avoidance steering control can be executed by referring to the processing result of step ST15. If the determination result of step ST16 is NO, that is, if emergency avoidance steering control cannot be executed, the driving assistance control device 6 proceeds to step ST14 and starts emergency avoidance braking control.

[0081] If the determination result in step ST16 is YES, that is, if emergency avoidance steering control can be executed, the driving assistance control device 6 proceeds to step ST17. In step ST17, the warning braking that is being executed is canceled, and the driving assistance control device 6 proceeds to step ST71 (see FIG. 8) to start emergency avoidance steering control.

[0082] In step ST18, in response to determining that the current state point is within region 1, the driving assistance control device 6 calculates the relative velocity and the collision prediction time from the current point (the point at which it was determined in step ST11 that the state point is below the collision possibility judgment line L3) after the above-mentioned automatic braking control rise time as the estimated relative velocity and the estimated collision prediction time, respectively, and proceeds to step ST19.

[0083] In step ST19, the driving assistance control device 6 determines whether or not the state point after the automatic braking control rise time specified by the estimated relative speed and estimated collision prediction time calculated in step ST18 is in a region equal to or less than the braking avoidance limit line L4 defined on the state map illustrated in Fig. 16. Here, in step ST19, the specific procedure for determining whether or not the state point is in a region equal to or less than the braking avoidance limit line L4 is the same as in step ST12 described above, and therefore a detailed description thereof will be omitted.

[0084] If the judgment result of step ST19 is YES, that is, if it is determined that the current state point is within region 1 but the state point will move into region 2 after the automatic braking control start-up time, the driving assistance control device 6 proceeds to step ST15 to execute emergency avoidance steering control.

[0085] Furthermore, if the determination result of step ST19 is NO, that is, if the current state point and the state point after the automatic braking control rise time are both within region 1, the driving assistance control device 6 proceeds to step ST14 to execute emergency avoidance braking control.

[0086] FIG. 6 is a flowchart showing a specific procedure for the steering avoidance control execution determination process.

[0087] First, in step ST21, the driving assistance control device 6 determines whether the target is a pedestrian crossing the roadway. If the determination result in step ST21 is YES, the driving assistance control device 6 proceeds to step ST22, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST25.

[0088] In step ST22, based on the forward information, the driving assistance control device 6 extracts at least one avoidable area within the vehicle's driving lane or the roadway excluding the sidewalk, excluding the predicted collision point (the point where a crossing pedestrian is estimated to be present after the predicted collision time) and the point where an obstacle exists, and which is larger than the body of the vehicle, and then proceeds to step ST23.

[0089] In step ST23, the driving assistance control device 6 detects the presence or absence of a moving object on the rear side based on the rear side information acquired by the external sensor unit 2, and then proceeds to step ST24.

[0090] In step ST24, the driving assistance control device 6 determines, from the multiple avoidable areas extracted in step ST22, the avoidable area that has the lowest risk of contact with the object and other moving objects, etc. and the lowest risk of the host vehicle tipping over, as the avoidance space, and proceeds to step ST28. In particular, at this time, if multiple avoidable areas have been extracted, the driving assistance control device 6 preferably determines, as the avoidance space, an avoidable area that is on the rear side of the moving direction of the object, who is a crossing pedestrian, with priority.

[0091] On the other hand, in step ST25, the driving assistance control device 6 extracts at least one avoidable area, based on the forward information, within the vehicle's driving lane or within the roadway excluding the sidewalk, excluding the point where the current object is located (since the object is not a crossing pedestrian, there is little movement along the vehicle width direction) and the point where an obstacle is located, and which is wider than the body of the vehicle, and then proceeds to step ST26.

[0092] In step ST26, the driving assistance control device 6 detects the presence or absence of a moving object on the rear side based on the rear side information acquired by the external sensor unit 2, and then proceeds to step ST27.

[0093] In step ST27, the driving assistance control device 6 determines, from the multiple avoidable areas extracted in step ST25, the avoidable area that has the lowest risk of contact with the target and other moving bodies and the lowest risk of the vehicle tipping over, as the avoidance space, and proceeds to step ST28. In particular, at this time, if multiple avoidable areas have been extracted, the driving assistance control device 6 preferably prioritizes an avoidable area that is wider or that is farther from the sidewalk in determining it as the avoidance space.

[0094] In step ST28, the driving assistance control device 6 determines whether or not an avoidance space has been determined, in other words, whether or not an avoidance space exists that can reduce the risk of contact with the target and other moving bodies, etc., and the risk of the vehicle tipping over. If the determination result in step ST28 is YES, the driving assistance control device 6 proceeds to step ST29, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST31.

[0095] In step ST29, the driving assistance control device 6 determines whether it is possible to change the traveling direction of the vehicle body to the determined avoidance space by executing automatic steering control. If the determination result in step ST29 is YES, the driving assistance control device 6 proceeds to step ST30, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST31.

[0096] In step ST30, the driving assistance controller 6 determines that emergency avoidance steering control can be executed, and proceeds to step ST16 (see FIG. 5). In step ST31, the driving assistance controller 6 determines that emergency avoidance steering control cannot be executed, and proceeds to step ST16 (see FIG. 5).

[0097] FIG. 7 is a flowchart showing the procedure of processing after emergency avoidance braking control is started in emergency braking control.

[0098] As shown in Fig. 7, in step ST51, the driving assistance control device 6 acquires updated forward information from the external sensor unit 2, and then proceeds to step ST52. In step ST52, the driving assistance control device 6 determines whether or not the object can be continuously recognized based on the forward information acquired in step ST51. If the determination result in step ST52 is YES, the driving assistance control device 6 proceeds to step ST53. In step ST53, the driving assistance control device 6 calculates the position of the object, the traveling direction of the object, the moving speed of the object along the traveling direction of the object, and the relative speed between the object and the subject vehicle, based on the forward information and the subject vehicle speed, and then proceeds to step ST54.

[0099] In step ST54, the driving assistance control device 6 calculates a predicted path of the vehicle based on the steering angle, and proceeds to step ST55. In step ST55, the driving assistance control device 6 determines, based on the forward information updated and acquired in step ST51, whether the pedestrian recognized in step ST52 has entered or is about to enter the predicted path of the vehicle calculated in step ST54. If the determination result in step ST55 is YES, the driving assistance control device 6 proceeds to step ST56.

[0100] In step ST56, the driving assistance control device 6 determines whether the object is moving away from the predicted collision point based on the information calculated in step ST53. If the determination result in step ST56 is YES, the driving assistance control device 6 proceeds to step ST57.

[0101] In step ST57, the driving assistance control device 6 determines that contact between the vehicle body and the object has been avoided due to the traveling direction of the object, ends the warning and emergency avoidance braking control that are being executed, and ends the emergency braking control.

[0102] If the determination result in step ST56 is NO, the driving assistance control device 6 proceeds to step ST58. In step ST58, the driving assistance control device 6 continues to execute emergency avoidance braking control, and returns to step ST51.

[0103] If the determination result in step ST52 is NO, i.e., if the object can no longer be recognized, the driving assistance control device 6 proceeds to step ST59. In step ST59, the driving assistance control device 6 determines whether or not an impact due to contact between the vehicle body and the object or an impact due to the vehicle body tipping over has been detected, based on the acceleration measured by the inertial measurement unit 32. If the determination result in step ST59 is YES, the driving assistance control device 6 proceeds to step ST60.

[0104] In step ST60, the driving assistance control device 6 determines that an accident has occurred, terminates the warning and emergency avoidance braking control that are being executed, and proceeds to step ST61. In step ST61, the driving assistance control device 6 makes an emergency call to an emergency call center using the emergency call device 5, and then terminates the emergency braking control.

[0105] Furthermore, if at least one of the determination results in step ST55 and step ST59 is NO, the driving assistance control device 6 proceeds to step ST62. In step ST62, the driving assistance control device 6 determines that contact between the vehicle body and the object has been avoided due to deceleration of the object, ends the warning and emergency avoidance braking control that are being executed, and ends the emergency braking control.

[0106] 8 and 9 are flowcharts showing a specific procedure for emergency avoidance steering control.

[0107] As shown in Fig. 8, in step ST71, the driving assistance control device 6 calculates a target path for the vehicle body to the avoidance space determined by the processing in Fig. 6, and then proceeds to step ST72. In step ST72, the driving assistance control device 6 calculates a steering control amount for moving the vehicle body along the target path, and then proceeds to step ST73. In step ST73, the driving assistance control device 6 starts automatic steering control based on the steering control amount calculated in step ST72, and then proceeds to step ST74.

[0108] In step ST74, the driving assistance control device 6 acquires updated forward information from the external sensor unit 2, and proceeds to step ST75. In step ST75, the driving assistance control device 6 determines whether or not it can continue to recognize the object based on the updated forward information acquired in step ST74. If the determination result in step ST75 is YES, the driving assistance control device 6 proceeds to step ST76, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST80.

[0109] In step ST76, the driving assistance control device 6 calculates the position of the object, the traveling direction of the object, the moving speed of the object along the traveling direction of the object, and the relative speed between the object and the own vehicle based on the forward information and the own vehicle speed, and then proceeds to step ST77. In step ST77, the driving assistance control device 6 calculates the predicted course of the own vehicle based on the steering angle, and then proceeds to step ST78. In step ST78, the driving assistance control device 6 determines, based on the forward information updated and acquired in step ST74, whether the pedestrian recognized in step ST75 has entered or is about to enter the predicted course of the own vehicle calculated in step ST77. If the determination result in step ST78 is YES, the driving assistance control device 6 proceeds to step ST79, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST81.

[0110] In step ST79, the driving assistance control device 6 determines that it is necessary to continue to execute emergency avoidance steering control for the target, and proceeds to step ST91 (see FIG. 9).

[0111] In step ST80, the driving assistance control device 6 determines whether or not an impact due to contact between the vehicle body and an object or an impact due to the vehicle body tipping over has been detected, based on the acceleration measured by the inertial measurement unit 32. If the determination result in step ST80 is NO, the driving assistance control device 6 proceeds to step ST81, and if the determination result is YES, the driving assistance control device 6 proceeds to step ST82.

[0112] In step ST81, the driving assistance control device 6 determines that it has succeeded in avoiding contact with the object, and proceeds to post-avoidance assistance processing, and then to step ST111 (see FIG. 10).

[0113] In step ST82, the driving assistance control device 6 determines that an accident has occurred, terminates the warning and emergency avoidance braking control that are being executed, and proceeds to step ST83. In step ST83, the driving assistance control device 6 makes an emergency call to an emergency call center using the emergency call device 5, and then terminates the emergency braking control.

[0114] 9, in step ST91, the driving assistance control device 6 recalculates the avoidance space based on the updated forward information acquired in step ST74, and proceeds to step ST92. In step ST92, the driving assistance control device 6 determines whether the recalculated avoidance space allows for continued avoidance. If the determination result in step ST92 is YES, the driving assistance control device 6 proceeds to step ST93.

[0115] In step ST93, the driving assistance control device 6 acquires updated rearward information from the external sensor unit 2, and proceeds to step ST94. In step ST94, the driving assistance control device 6 determines whether or not another moving object is present to the rearward side in the steering direction under automatic steering control, based on the updated rearward information acquired in step ST93. If the determination result in step ST94 is NO, the driving assistance control device 6 proceeds to step ST95.

[0116] In step ST95, the driving assistance control device 6 calculates a target path for the vehicle body to the avoidance space calculated in step ST91, and then proceeds to step ST96. In step ST96, the driving assistance control device 6 calculates a steering control amount for moving the vehicle body along the target path, and then proceeds to step ST97. In step ST97, the driving assistance control device 6 continues to perform automatic steering control based on the steering control amount calculated in step ST96, and then proceeds to step ST74 (see FIG. 8).

[0117] If the determination result in the above-mentioned step ST92 is NO, the driving assistance control device 6 proceeds to step ST98 to stop the emergency avoidance steering control that is currently being performed and to transition to emergency avoidance braking control. In a situation immediately before a collision, it may be difficult to change the traveling direction of the vehicle body. In such a case, it is better to quickly stop the emergency avoidance steering control and transition to emergency avoidance braking control, so that damage to both parties can be reduced. Furthermore, if the determination result in the above-mentioned step ST94 is YES, that is, if another moving object is present to the rear side in the steering direction, the driving assistance control device 6 proceeds to step ST98 to stop the emergency avoidance steering control that is currently being performed and to transition to emergency avoidance braking control.

[0118] In step ST98, the driving assistance control device 6 starts automatic steering control to keep the vehicle body upright, and then proceeds to step ST99. At this time, the driving assistance control device 6 may keep the vehicle body upright by combining automatic steering control and automatic attitude control.

[0119] In step ST99, the driving assistance control device 6 determines whether the vehicle body is upright. If the determination result in step ST99 is NO, the driving assistance control device 6 proceeds to step ST100, and if the determination result is YES, the driving assistance control device 6 proceeds to step ST101. In step ST100, the driving assistance control device 6 continues to execute automatic steering control to keep the vehicle body upright, and then returns to step ST99. In step ST101, the driving assistance control device 6 starts emergency avoidance braking control, and then proceeds to step ST51 (see FIG. 7).

[0120] 10 to 15 are flowcharts showing the specific steps of the post-avoidance support process.

[0121] 10, in step ST111, the driving assistance control device 6 determines whether or not the rider has performed a steering operation or a braking operation while emergency avoidance steering control is being executed. If the determination result in step ST111 is YES, the driving assistance control device 6 proceeds to step ST112, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST113.

[0122] In step ST112, the driving assistance control device 6 determines that the rider can continue driving, and ends the warning and automatic steering control that are being executed, and ends the emergency braking control.

[0123] In step ST113, the driving assistance control device 6 issues a warning to prompt the rider to perform an operation, and proceeds to step ST114. An example of the warning to prompt the rider to perform an operation here is warning braking. In step ST114, the driving assistance control device 6 acquires updated forward information from the external sensor unit 2, and proceeds to step ST115. In step ST115, the driving assistance control device 6 determines whether or not there is a new obstacle in front of the vehicle body that may cause a collision, based on the updated forward information acquired in step ST114. If the determination result in step ST115 is YES, the driving assistance control device 6 proceeds to step ST116, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST118.

[0124] In step ST116, the driving assistance control device 6 determines whether the obstacle recognized in step ST115 is a pedestrian. If the determination result in step ST116 is YES, the driving assistance control device 6 returns to step ST1 (see FIG. 4) to resume emergency braking control targeting this new pedestrian. On the other hand, if the determination result in step ST116 is NO, the driving assistance control device 6 proceeds to step ST117. In step ST117, the driving assistance control device 6 ends the ongoing warning and automatic steering control and ends the emergency braking control in order to start emergency braking control targeting this new obstacle.

[0125] In step ST118, the driving assistance control device 6 proceeds to a stop assistance process for safely stopping the vehicle body, and then proceeds to step ST121 (see FIG. 11).

[0126] 11, in step ST121, the driving assistance control device 6 acquires the current lane (i.e., the dividing line separating the current lane from an adjacent lane) based on the forward information updated and acquired in step ST114, and proceeds to step ST122. In step ST122, the driving assistance control device 6 determines whether the avoidance direction by emergency avoidance steering control is toward the shoulder of the road. If the determination result in step ST121 is YES, the driving assistance control device 6 proceeds to step ST123, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST124.

[0127] In step ST123, the driving assistance control device 6 sets the target route of the vehicle body to follow the shoulder side of the own lane acquired in step ST121 so that the own vehicle does not obstruct the following vehicle, and then proceeds to step ST125.

[0128] In step ST124, the driving assistance controller 6 sets a target path for the vehicle body so that the current position of the vehicle body along the width direction within the own lane does not change, and then proceeds to step ST125.

[0129] In step ST125, the driving assistance control device 6 calculates a steering control amount for moving the vehicle body along the calculated target route, and then proceeds to step ST126. In step ST126, the driving assistance control device 6 executes automatic steering control based on the calculated steering control amount, and then proceeds to step ST127.

[0130] In step ST127, the driving assistance controller 6 determines whether or not the vehicle body has been brought upright in a state parallel to the vehicle's own lane. If the determination result in step ST127 is YES, the driving assistance controller 6 proceeds to step ST161 (see FIG. 14), and if the determination result is NO, the driving assistance controller 6 proceeds to step ST131 (see FIG. 12).

[0131] As shown in Fig. 12, in step ST131, the driving assistance control device 6 determines whether or not the rider has performed a steering operation or a braking operation after starting the post-avoidance assistance processing shown in Fig. 10 to Fig. 15. If the determination result in step ST131 is YES, the driving assistance control device 6 proceeds to step ST132, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST133.

[0132] In step ST132, the driving assistance control device 6 determines that the rider can continue driving, and ends the warning and automatic steering control that are being executed, and ends the emergency braking control.

[0133] In step ST133, the driving assistance control device 6 acquires updated forward information from the external sensor unit 2 and proceeds to step ST134. In step ST134, the driving assistance control device 6 determines whether or not there is a new obstacle in front of the vehicle body that may cause a collision, based on the updated forward information acquired in step ST133. If the determination result in step ST134 is YES, the driving assistance control device 6 proceeds to step ST135, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST137.

[0134] In step ST135, the driving assistance control device 6 determines whether the obstacle recognized in step ST134 is a pedestrian. If the determination result in step ST135 is YES, the driving assistance control device 6 returns to step ST1 (see FIG. 4) to resume emergency braking control targeting this new pedestrian. On the other hand, if the determination result in step ST135 is NO, the driving assistance control device 6 proceeds to step ST136. In step ST136, the driving assistance control device 6 ends the ongoing warning and automatic steering control and ends the emergency braking control in order to start emergency braking control targeting this new obstacle.

[0135] In step ST137, the driving assistance controller 6 proceeds to a stop assistance process for safely stopping the vehicle body, and then proceeds to step ST141 (see FIG. 13).

[0136] 13, in step ST141, the driving assistance control device 6 acquires the current lane based on the forward information updated and acquired in step ST133, and proceeds to step ST142. In step ST142, the driving assistance control device 6 sets the target route according to the same procedure as the previous time (step ST123 or step ST124), and proceeds to step ST143.

[0137] In step ST143, the driving assistance control device 6 determines whether the previously set target route and the currently set target route are continuous. If the determination result in step ST143 is YES, the driving assistance control device 6 proceeds to step ST144, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST145. Here, cases in which the previously set target route and the currently set target route are not continuous may be due to, for example, a malfunction of the external sensor unit 2 caused by a fall or a change in the environment ahead (such as blurred white lines).

[0138] In step ST144, the driving assistance control device 6 calculates the steering control amount for moving the vehicle body along the target route set in step ST142, and then returns to step ST126 (see FIG. 11).

[0139] In step ST145, the driving assistance control device 6 determines whether or not an impact due to contact between the vehicle body and an object or an impact due to the vehicle body tipping over has been detected, based on the acceleration measured by the inertial measurement unit 32. If the determination result in step ST145 is YES, the driving assistance control device 6 proceeds to step ST146, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST148.

[0140] In step ST146, the driving assistance control device 6 determines that an accident has occurred, terminates the ongoing warning and post-avoidance assistance processing, and proceeds to step ST147. In step ST147, the driving assistance control device 6 makes an emergency call to the emergency call center using the emergency call device 5, and then terminates the emergency braking control.

[0141] In step ST148, the driving assistance control device 6 starts automatic steering control for uprighting the vehicle body, and proceeds to step ST149. At this time, the driving assistance control device 6 may upright the vehicle body by combining automatic steering control and automatic attitude control.

[0142] In step ST149, the driving assistance control device 6 determines whether the vehicle body is upright. If the determination result in step ST149 is NO, the driving assistance control device 6 proceeds to step ST150, and if the determination result is YES, the driving assistance control device 6 proceeds to step ST161 (see FIG. 14). In step ST150, the driving assistance control device 6 continues to execute automatic steering control to keep the vehicle body upright, and then returns to step ST149.

[0143] 14, in step ST161, the driving assistance control device 6 issues a warning to prompt the rider to perform an operation, and then proceeds to step ST162. An example of the warning to prompt the rider to perform an operation here is warning braking. Because it is difficult for a motorcycle to maintain a stopped state, the driving assistance control device 6 issues a warning to prompt the rider to perform an operation before starting automatic braking control in the next step ST162.

[0144] In step ST162, the driving assistance control device 6 starts automatic braking control to automatically stop the upright vehicle body at a safe position, and then proceeds to step ST163. In step ST163, the driving assistance control device 6 acquires updated forward information from the external sensor unit 2, and then proceeds to step ST164.

[0145] In step ST164, the driving assistance control device 6 determines whether the forward information acquired in step ST163 is continuous from the previous acquisition. If the determination result in step ST164 is YES, the driving assistance control device 6 proceeds to step ST165, and if the determination result is NO, the driving assistance control device 6 determines that the vehicle body has overturned and proceeds to step ST168.

[0146] In step ST165, the driving assistance control device 6 determines whether or not there is an obstacle in front of the vehicle body that may cause a collision, based on the forward information updated and acquired in step ST163. If the determination result in step ST165 is YES, the driving assistance control device 6 proceeds to step ST166, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST168.

[0147] In step ST166, the driving assistance control device 6 determines whether the obstacle recognized in step ST165 is a pedestrian. If the determination result in step ST166 is YES, the driving assistance control device 6 returns to step ST1 (see FIG. 4) to resume emergency braking control targeting this new pedestrian. On the other hand, if the determination result in step ST166 is NO, the driving assistance control device 6 proceeds to step ST167. In step ST167, the driving assistance control device 6 ends the ongoing warning and automatic braking control, and then ends the emergency braking control, in order to start emergency braking control targeting this new obstacle.

[0148] In step ST168, the driving assistance control device 6 determines whether or not an impact due to contact between the vehicle body and an object or an impact due to the vehicle body overturning has been detected, based on the acceleration measured by the inertial measurement unit 32. If the determination result in step ST168 is YES, the driving assistance control device 6 proceeds to step ST170, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST168. In step ST168, the driving assistance control device 6 continues the automatic braking control started in step ST162, and proceeds to step ST181 (see FIG. 15).

[0149] In step ST170, the driving assistance control device 6 determines that an accident has occurred, terminates the warning and automatic braking control that are being executed, and proceeds to step ST171. In step ST171, the driving assistance control device 6 makes an emergency call to an emergency call center using the emergency call device 5, and then terminates the emergency braking control.

[0150] 15, in step ST181, the driving assistance control device 6 determines whether or not automatic braking control has been temporarily suspended since the previous time. If the determination result in step ST181 is YES, the driving assistance control device 6 proceeds to step ST182, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST184.

[0151] In step ST182, the driving assistance control device 6 determines whether or not the vehicle has passed through an intersection. If the determination result in step ST182 is YES, the driving assistance control device 6 proceeds to step ST183, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST185. In step ST183, the driving assistance control device 6 resumes the automatic braking control that was temporarily suspended, and proceeds to step ST163 (see FIG. 14). In addition, in step ST185, the automatic braking control that is being executed is temporarily suspended, and proceeds to step ST163 (see FIG. 14).

[0152] In step ST184, the driving assistance control device 6 determines whether or not an intersection is present ahead. If the determination result in step ST184 is YES, the driving assistance control device 6 proceeds to step ST185, and if the determination result is NO, the driving assistance control device 6 proceeds to step ST186. In step ST186, the driving assistance control device 6 continues the automatic braking control that is being executed, and proceeds to step ST187.

[0153] In step ST187, the driving assistance control device 6 determines whether or not the vehicle body has stopped. If the determination result in step ST187 is NO, the driving assistance control device 6 returns to step ST163 (see FIG. 14), and if the determination result in step ST187 is YES, the driving assistance control device 6 proceeds to step ST188. In step ST188, the driving assistance control device 6 determines that the vehicle body has moved to a safe position, terminates the warning and automatic braking control that are being executed, and proceeds to step ST189. In step ST189, the driving assistance control device 6 notifies the rider that the post-avoidance assistance processing has ended, and terminates the emergency braking control.

[0154] As described above, the driving assist control device 6 avoids contact with the object by executing the emergency avoidance automatic steering control, and then executes the post-avoidance support processing shown in Figures 10 to 15. In this post-avoidance support processing, the driving assist control device 6 decelerates the vehicle body while keeping it upright by executing a combination of automatic steering control (see step ST148), automatic attitude control (see step ST148), and automatic braking control (see step ST162). This makes it possible to avoid both contact with the object and the vehicle tipping over.

[0155] The driving assistance system 1 according to this embodiment has the following advantages. (1) In the driving assistance system 1, the driving assistance control device 6 executes automatic braking control, which automatically operates the brake device 83 at a timing determined based on the predicted collision time calculated by the prediction control unit 60. Here, when the target is a pedestrian, the driving assistance control device 6 executes emergency avoidance braking control when the relative speed calculated by the prediction control unit 60 is less than a speed threshold determined based on the predicted collision time, and executes emergency avoidance steering control, which automatically changes the traveling direction of the vehicle body, when the relative speed is equal to or greater than the speed threshold. Therefore, according to the driving assistance system 1, when the relative speed is less than the speed threshold and contact with the target can be avoided by emergency avoidance braking control, emergency avoidance braking control, which reduces the risk of the host vehicle tipping over, is executed, thereby avoiding contact between the host vehicle and the target and preventing damage caused by tipping over of the host vehicle. Furthermore, when the relative speed is equal to or greater than the speed threshold and contact with the target cannot be avoided by automatic emergency avoidance braking control, emergency avoidance steering control is executed, thereby avoiding contact between the host vehicle and the target. Therefore, according to the driving assistance system 1, by switching between emergency avoidance braking control and emergency avoidance steering control depending on the relative speed to the object and the predicted collision time, it is possible to avoid contact between the vehicle and a pedestrian object as much as possible, thereby improving traffic safety.

[0156] (2) By setting the speed threshold to a smaller value as the collision prediction time becomes shorter, the driving assistance control device 6 can appropriately distinguish between cases where contact can be avoided by emergency avoidance braking control and cases where contact can be avoided by emergency avoidance steering control, thereby making it possible to avoid contact between pedestrians and the vehicle as much as possible.

[0157] (3) When the relative speed is equal to or greater than the speed threshold and there is an avoidance space near the target that is free of at least one obstacle, the driving assistance control device 6 executes emergency avoidance steering control to change the traveling direction of the vehicle body toward the avoidance space, and when the relative speed is equal to or greater than the speed threshold and there is no avoidance space, the driving assistance control device 6 executes emergency avoidance braking control. This makes it possible to prevent the vehicle body from coming into contact with an obstacle after changing the traveling direction of the vehicle body to avoid contact with the target, thereby further improving traffic safety.

[0158] (4) The driving assistance control device 6 determines whether or not there is an avoidance space within the roadway excluding the vehicle's lane or the sidewalk. This prevents the vehicle from colliding with another moving object traveling in an adjacent lane or running onto the sidewalk after changing the vehicle's direction to avoid contact with an object, thereby further improving traffic safety.

[0159] (5) When the target is a pedestrian crossing the roadway, the driving assistance control device 6 determines whether or not there is an avoidance space by prioritizing the rear side of the target's direction of movement over the front side of the target's direction of movement. This makes it possible to more reliably avoid contact between the vehicle and the target, thereby further improving traffic safety.

[0160] (6) The prediction control unit 60 calculates the relative speed and the collision prediction time from the time when it is determined that the collision prediction time is equal to or less than the collision possibility judgment time threshold (i.e., the collision possibility judgment line L3) until the automatic braking control rise time as the estimated relative speed and the estimated collision prediction time, respectively, and the driving assistance control device 6 executes emergency avoidance braking control when the estimated relative speed is less than the speed threshold determined based on the estimated collision prediction time, and executes emergency avoidance steering control when the estimated relative speed is equal to or greater than the speed threshold. Therefore, according to the driving assistance system 1, when the collision prediction time becomes equal to or less than the collision possibility judgment threshold, it is possible to appropriately determine whether to execute emergency avoidance braking control or emergency avoidance steering control, taking into account the time required for the emergency avoidance braking control to rise, thereby making it possible to avoid contact between the vehicle and the object as much as possible, and ultimately to further improve traffic safety.

[0161] (7) When the collision prediction time is equal to or less than the warning braking judgment time threshold (i.e., warning braking judgment line L2) that is set larger than the collision possibility judgment time threshold, i.e., before executing emergency avoidance braking control or emergency avoidance steering control, the driving assistance control device 6 automatically operates the brake device to generate braking force intermittently, thereby executing warning braking that vibrates the vehicle body and ultimately the part of the rider's body that is in contact with the vehicle body. This makes it possible to reliably make the rider aware of the presence of the object before starting emergency avoidance braking control or emergency avoidance steering control, thereby making it possible to avoid contact between the vehicle and the object as much as possible, and ultimately to further improve traffic safety.

[0162] (8) After avoiding contact with the object by executing emergency avoidance steering control, the driving assistance control device 6 executes post-avoidance assistance processing to decelerate the vehicle body while keeping it upright by automatically operating the brake device and steering device. This makes it possible to avoid both contact between the vehicle and the object and the vehicle tipping over, thereby further improving traffic safety.

[0163] Although one embodiment of the present invention has been described above, the present invention is not limited to this, and the detailed configuration may be modified as appropriate within the scope of the spirit of the present invention. [Explanation of symbols]

[0164] 1. Driving assistance system 2...External sensor unit 21...Front sensor unit (forward information acquisition means) 22...Rear sensor unit 3...Vehicle sensor unit 5…Emergency call device 6... Driving assistance control device (driving assistance control means) 60...Prediction control unit (prediction means) 61...Automatic braking control unit 62...Automatic steering control unit 64...Attitude control unit 65...Emergency call control unit 66...Alarm control unit 81...Driving controls 82...Traveling driving force output device 83...Brake device 84...Rear wheel rocking mechanism 85...Steering device

Claims

1. a forward information acquisition means for acquiring forward information relating to a state ahead of a body of the host vehicle, which is a motorcycle; a prediction means for calculating a relative speed and a predicted collision time between the vehicle body and an object ahead of the vehicle body based on the forward information; a driving assistance control means for executing automatic braking control that automatically operates a braking device at a timing determined based on the collision prediction time, a driving assistance system characterized in that, when the target is a pedestrian, the driving assistance control means executes the automatic braking control when the relative speed is less than a speed threshold determined based on the collision prediction time, and executes a traveling direction change control that automatically changes the traveling direction of the vehicle body when the relative speed is equal to or greater than the speed threshold.

2. 2. The driving assistance system according to claim 1, wherein the driving assistance control means sets the speed threshold to a smaller value as the collision prediction time becomes shorter.

3. 3. The driving assistance system according to claim 1, wherein the driving assistance control means executes the traveling direction change control to change the traveling direction of the vehicle body to the avoidance space when the relative speed is equal to or greater than the speed threshold and there is an avoidance space near the target that is free from at least one obstacle, and executes the automatic braking control when the relative speed is equal to or greater than the speed threshold and there is no avoidance space.

4. 4. The driving assistance system according to claim 3, wherein the driving assistance control means determines whether or not the avoidance space exists within a driving lane of the host vehicle or within a roadway excluding a sidewalk.

5. 5. The driving assistance system according to claim 3, wherein, when the object is a pedestrian crossing the roadway, the driving assistance control means determines whether or not the avoidance space exists by prioritizing the rear side of the object in the direction of movement rather than the front side in the direction of movement of the object.

6. the prediction means calculates the relative velocity and the collision prediction time from a time point at which it is determined that the collision prediction time is equal to or shorter than a predetermined first time threshold until a rise time of the automatic braking control has elapsed, as an estimated relative velocity and an estimated collision prediction time, respectively; 6. The driving assistance system according to claim 1, wherein the driving assistance control means executes the automatic braking control when the estimated relative speed is less than the speed threshold determined based on the estimated collision prediction time, and executes the direction change control when the estimated relative speed is equal to or greater than the speed threshold.

7. The driving assistance system according to claim 6, characterized in that, when the collision prediction time is equal to or less than a second time threshold set greater than the first time threshold, the driving assistance control means automatically operates the brake device to intermittently generate braking force, thereby executing warning braking that vibrates the vehicle body.

8. 8. The driving assistance system according to claim 1, wherein the driving assistance control means executes the travel direction change control to avoid contact with the object, and then executes a post-avoidance assistance process to decelerate the vehicle body while keeping it upright by automatically operating the brake device and the steering device.

9. a forward information acquisition means for acquiring forward information relating to a state ahead of a body of the host vehicle, which is a motorcycle; a prediction means for calculating a relative speed and a predicted collision time between the vehicle body and an object ahead of the vehicle body based on the forward information; a driving assistance control means for executing automatic braking control that automatically operates a braking device at a timing determined based on the collision prediction time, and when the target is a pedestrian, the driving assistance control means executes the automatic braking control when the collision prediction time is greater than a time threshold determined based on the relative speed, and executes a traveling direction change control that automatically controls the traveling direction of the vehicle body when the collision prediction time is equal to or less than the time threshold.

10. The driving assistance system according to claim 9 , wherein the driving assistance control means sets the time threshold to a smaller value as the relative speed decreases.

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