FCW device for saddle-type vehicle and FCW method for saddle-type vehicle

Abstract

This FCW device for a saddle-type vehicle comprises: a warning unit which issues a warning to a driver; and at least one control unit which executes a host vehicle course prediction for predicting the course of a host vehicle and a host vehicle peripheral object position detection for detecting the position of an object around the host vehicle, calculates a collision likelihood between the host vehicle and the object by using the result of the host vehicle course prediction and the result of the host vehicle peripheral object position detection, and executes warning control for controlling the presence or absence of the warning by the warning unit on the basis of the collision likelihood. The FCW device for the saddle-type vehicle is used in a saddle-type vehicle. The FCW device for a saddle-type vehicle further comprises a monocular camera that is fixed to the host vehicle and captures an image of the surroundings of the host vehicle. The control unit is characterized by executing calculation of a temporal change of the relative position of the object detected by the host vehicle peripheral object position detection in a captured image captured by the monocular camera, and executing warning control as described in each of the following situations by using the results of the host vehicle course prediction, the host vehicle peripheral object position detection, and the temporal change of the relative position. Situation 1: When the host vehicle is travelling straight at a vehicle speed V1 on a road having no white lines, if a first preceding vehicle is traveling straight in the same direction as the host vehicle at a vehicle speed V2 (V2 < V1) smaller than the vehicle speed of the host vehicle and is in a position which is on an extension of the center line in the vehicle width direction of the host vehicle and is ahead of the host vehicle, the control unit executes the warning control so that the warning unit issues a warning when the collision likelihood between the host vehicle and the first preceding vehicle is equal to or greater than a predetermined collision likelihood. Situation 2: When the host vehicle is travelling straight at a vehicle speed V3 on a road having no white lines, if a second preceding vehicle is traveling so as to pass a position which is on an extension of the center line in the width direction of the host vehicle, is ahead of the host vehicle, and is at an inter-vehicle distance equal to the inter-vehicle distance between the host vehicle and the first preceding vehicle when the warning is issued by the warning unit in Situation 1, at a vehicle speed such that the relative speed with the host vehicle is the relative speed (V2-V1) of Situation 1, the control unit executes the warning control so that no warning is issued by the warning unit. Situation 3: In a situation where the relative position between the host vehicle and a third preceding vehicle changes such that Situation 3(a) described below changes to Situation 3(b) described below, the control unit executes the warning control so that no warning is issued by the warning unit. Situation 3(a): When the host vehicle is travelling straight at a vehicle speed V1 on a road without white lines, the third preceding vehicle is traveling in the same direction as the host vehicle at a vehicle speed V2 (V2 < V1) smaller than the vehicle speed of the host vehicle in a position which is on an extension of the central line in the width direction of the host vehicle and is such that the position of the right end of the vehicle body of the third preceding vehicle is the same as the position of the right end of the vehicle body of the host vehicle in the vehicle width direction, and the inter-vehicle distance between the host vehicle and the third preceding vehicle is greater than the inter-vehicle distance between the host vehicle and the first preceding vehicle when the warning is issued by the warning unit in Situation 1. Situation 3(b): In a situation in which the third preceding vehicle rotates the traveling direction to the right by 20 degrees and the right end of the vehicle body of the host vehicle is on the right side of the left end of the vehicle body of the third preceding vehicle and on the left side of the vehicle body center position in the vehicle body width direction of the third preceding vehicle, the inter-vehicle distance between the host vehicle and the third preceding vehicle is the same as the inter-vehicle distance between the host vehicle and the first preceding vehicle when the warning is issued by the warning unit.

Description

FCW device for saddle-riding type vehicle and FCW method for saddle-riding type vehicle

[0001] The present disclosure relates to a FCW device for a saddle-ride type vehicle and a FCW method for a saddle-ride type vehicle that issues a forward collision warning (FCW) to a driver of the saddle-ride type vehicle.

[0002] Conventionally, FCW devices are known that issue a warning to a driver of a saddle-riding vehicle based on the possibility of a collision with a surrounding object. An example of a saddle-riding vehicle is a motorcycle. For example, Patent Document 1 discloses a device that issues a warning based on the positional relationship between a saddle-riding vehicle and a preceding vehicle traveling in front of the saddle-riding vehicle when multiple saddle-riding vehicles are traveling together. Patent Document 2 discloses a system that captures an image of the front using a camera attached to the saddle-riding vehicle, detects surrounding vehicles using the captured image, and issues a warning.

[0003] International Publication No. 2021 / 060357 Special Publication No. 2021-526681

[0004] Compared to a non-saddle-ride type four-wheel vehicle, a straddle-type vehicle has a greater degree of freedom in the relative position that it can assume with respect to surrounding vehicles while traveling. The techniques disclosed in Patent Documents 1 and 2 do not sufficiently consider FCW control that takes into account the above characteristics of a straddle-type vehicle.

[0005] An object of the present disclosure is to provide an FCW device for a saddle-riding type vehicle and an FCW method for a saddle-riding type vehicle that perform FCW control different from conventional methods.

[0006] In an FCW device for a saddle-riding vehicle, it is conceivable to calculate the probability of collision between the vehicle and a nearby vehicle using the positions of objects (neighboring vehicles) around the vehicle on an image captured by an on-board camera and predicted path information for the vehicle. The present inventors have considered using the conventional technologies of Patent Documents 1 and 2 in an FCW device for a saddle-riding vehicle in various situations. As a result of their consideration, the present inventors have noticed that there are situations where a nearby vehicle is on the predicted path of the vehicle, even though the possibility of a collision is low. Examples of such situations include a situation where an oncoming vehicle passes another vehicle just before a turning circle (hereinafter also referred to as a passing just before a turning circle) and a situation where a leading vehicle traveling ahead of the vehicle changes lanes (hereinafter also referred to as a leading vehicle out).

[0007] The inventors of the present application also considered a situation specific to saddle-ride type vehicles, in which the vehicle changes its position in the width direction of the lane while traveling within the lane, as a situation specific to saddle-ride type vehicles. It is conceivable that a saddle-ride type vehicle will change its position in the width direction of the lane while traveling within the lane depending on the surrounding road conditions and the traveling conditions of surrounding vehicles.

[0008] In light of the above, the inventors of the present application have come to propose an FCW device for saddle-riding vehicles that takes into consideration the degree of freedom in lane width positioning that is unique to saddle-riding vehicles, and that is capable of suppressing the recognition of nearby vehicles with a low risk of collision as obstacles and sounding an alarm in situations such as the aforementioned passing just before a turning circle or when the preceding vehicle is out of position.

[0009] In general, in FCW control, after detecting objects around the vehicle, an object that is likely to collide with the vehicle is selected from the detected objects. Then, to determine whether to issue a warning to the driver of the vehicle, for example, the time to collision (TTC) between the selected object and the vehicle is calculated. The FCW device executes multiple processes from the time the object is detected until the warning is issued to the driver. Since straddle-type vehicles have limited space for installing devices such as an FCW device compared to four-wheeled vehicles, it is necessary to increase the design flexibility of image processing hardware resources by reducing the processing load in various locations.

[0010] The inventors of the present application have investigated a configuration in which the relative movement between the vehicle and surrounding vehicles is detected using images captured by a monocular camera fixed to the vehicle body, and the vehicle to be warned is selected without detecting white lines, and it is determined whether or not to issue a warning. As a result, they have found that it is possible to increase the degree of freedom in designing hardware resources for image processing while controlling warnings in consideration of the above-mentioned situations.

[0011] The FCW device for a saddle-ride type vehicle according to the present disclosure employs the following configuration in order to achieve both of the above-mentioned problems associated with the saddle-ride type vehicle.

[0012] An FCW device for a saddle-riding type vehicle according to one embodiment of the present disclosure includes an alarm unit that issues an alarm to a driver, and one or more control units that perform host vehicle path prediction to predict a path of the host vehicle and host vehicle peripheral object position detection to detect the positions of objects around the host vehicle, calculate a possibility of a collision between the host vehicle and an object using the host vehicle path prediction result and the host vehicle peripheral object position detection result, and perform alarm control that controls whether or not an alarm is issued by the alarm unit based on the possibility of collision. The FCW device for a saddle-riding type vehicle is used in a saddle-riding type vehicle and further includes a monocular camera that is fixed to the host vehicle and captures images of the area around the host vehicle, and the control unit calculates changes over time in the relative positions of objects detected in the host vehicle peripheral object position detection relative to the host vehicle in the images captured by the monocular camera, and performs the alarm control using the results of the host vehicle path prediction, the host vehicle peripheral object position detection, and the changes over time in the relative positions, as described in each of the following situations. Situation 1: When the host vehicle is traveling straight at a vehicle speed V1 on a road without white lines and a first leading vehicle is traveling straight in the same direction as the host vehicle at a vehicle speed V2 (V2<V1) that is slower than the vehicle speed of the host vehicle and passes a position that is an extension of the center line of the host vehicle in the vehicle width direction and is in front of the host vehicle, the control unit executes the warning control so that the warning unit issues a warning when the possibility of a collision between the host vehicle and the first leading vehicle reaches a predetermined collision possibility or higher. Situation 2: When the host vehicle is traveling straight at a vehicle speed V3 on a road without white lines and a second leading vehicle is traveling so that the relative speed between the host vehicle and the first leading vehicle is the relative speed (V2-V1) in situation 1 and passes a position that is an extension of the center line of the host vehicle in the vehicle width direction and is in front of the host vehicle, and the inter-vehicle distance between the host vehicle and the first leading vehicle is the same as the inter-vehicle distance between the host vehicle and the first leading vehicle when the warning unit issued the warning in situation 1, the control unit executes the warning control so that the warning unit does not issue a warning. Situation 3: In a situation where the relative position between the vehicle and the third preceding vehicle changes from situation 3(a) to situation 3(b) described below, the control unit executes the warning control so that the warning unit does not issue a warning.Situation 3(a): While the subject vehicle is traveling straight on a road without white lines at a vehicle speed V1, a third preceding vehicle is located ahead of the subject vehicle on an extension of the vehicle width center line, and is traveling in the same direction as the subject vehicle at a vehicle speed V2 (V2 < V1) that is slower than the vehicle speed of the subject vehicle, at a position where the position of the right end of the body of the third preceding vehicle is the same as the position of the right end of the body of the subject vehicle in the vehicle width direction, and the inter-vehicle distance between the subject vehicle and the third preceding vehicle is greater than the inter-vehicle distance between the subject vehicle and the first preceding vehicle when the alarm was issued by the alarm unit in situation 1. Situation 3(b): The third leading vehicle turns its direction of travel 20 degrees to the right, and the right edge of the host vehicle is to the right of the left edge of the third leading vehicle and to the left of the center position of the third leading vehicle in the vehicle width direction, and the inter-vehicle distance between the host vehicle and the third leading vehicle becomes the same as the inter-vehicle distance between the host vehicle and the first leading vehicle when the alarm was issued by the alarm unit in Situation 1. One feature of the FCW device for a saddle-riding vehicle is that it calculates the time change in the relative position of an object detected in the position detection of an object around the host vehicle relative to the host vehicle, and is capable of executing different alarm controls depending on the host vehicle path prediction, the position detection of the object around the host vehicle, and the time change in the relative position. Due to this feature, the FCW device for a saddle-riding vehicle issues an alarm when Situation 1 is reproduced, and does not issue an alarm when Situation 2 or Situation 3 is reproduced. Situations 1, 2, and 3 are merely example situations to illustrate the characteristics of the FCW device for saddle-riding type vehicles according to the present disclosure, and are not intended to limit the warning control by the FCW device for saddle-riding type vehicles to these situations.

[0013] In the above configuration, when the host vehicle is traveling straight on a road without white lines at a vehicle speed V3 equal to the relative speed between the host vehicle and the second leading vehicle in situation 1, and a fourth leading vehicle is stopped sideways to the direction of travel of the host vehicle at a position extended from the center line of the host vehicle's width direction and in front of the host vehicle, the control unit may execute the warning control so that the warning unit will issue a warning when the inter-vehicle distance between the host vehicle and the fourth leading vehicle becomes the same as the inter-vehicle distance between the host vehicle and the first leading vehicle when the warning unit issued a warning in situation 1.

[0014] In the above configuration, in calculating the change over time of the relative position, the control unit may calculate a movement vector from the difference between the detection coordinates of objects around the vehicle in multiple images captured by the monocular camera, or may calculate the movement vector using optical flow.

[0015] An FCW method for a saddle-riding type vehicle according to one embodiment of the present disclosure includes a warning unit that issues a warning to a driver, and one or more control units that perform host vehicle path prediction to predict a path of the host vehicle and host vehicle peripheral object position detection to detect the positions of objects around the host vehicle, calculate a possibility of a collision between the host vehicle and an object using the host vehicle path prediction result and the host vehicle peripheral object position detection result, and perform warning control that controls whether or not to issue a warning by the warning unit based on the possibility of collision, and is an FCW method for a saddle-riding type vehicle for an FCW device used in a saddle-riding type vehicle that leans to the inside of a turn when turning, the FCW method for a saddle-riding type vehicle includes a step of calculating a time change in the relative position of an object detected in the host vehicle peripheral object position detection relative to the host vehicle in an image captured by a monocular camera fixed to the host vehicle that captures an image of the periphery of the host vehicle, and a step of performing the warning control as described in each of the following situations using the results of the host vehicle path prediction, the host vehicle peripheral object position detection, and the time change in the relative position. Situation 1: When the host vehicle is traveling straight at a vehicle speed V1 on a road without white lines and a first leading vehicle is traveling straight in the same direction as the host vehicle at a vehicle speed V2 (V2<V1) that is slower than the vehicle speed of the host vehicle and passes a position that is an extension of the center line of the host vehicle in the vehicle width direction and is in front of the host vehicle, the control unit executes the warning control so that the warning unit issues a warning when the possibility of a collision between the host vehicle and the first leading vehicle reaches a predetermined collision possibility or higher. Situation 2: When the host vehicle is traveling straight at a vehicle speed V3 on a road without white lines and a second leading vehicle is traveling so that the relative speed between the host vehicle and the first leading vehicle is the relative speed (V2-V1) in situation 1 and passes a position that is an extension of the center line of the host vehicle in the vehicle width direction and is in front of the host vehicle, and the inter-vehicle distance between the host vehicle and the first leading vehicle is the same as the inter-vehicle distance between the host vehicle and the first leading vehicle when the warning unit issued the warning in situation 1, the control unit executes the warning control so that the warning unit does not issue a warning. Situation 3: In a situation where the relative position between the vehicle and the third preceding vehicle changes from situation 3(a) to situation 3(b) described below, the control unit executes the warning control so that the warning unit does not issue a warning.Situation 3(a): While the subject vehicle is traveling straight on a road without white lines at a vehicle speed V1, the third preceding vehicle is located ahead of the subject vehicle on an extension of the vehicle width center line, and is traveling in the same direction as the subject vehicle at a vehicle speed V2 (V2 < V1) that is slower than the vehicle speed of the subject vehicle, at a position where the position of the right end of the body of the third preceding vehicle is the same as the position of the right end of the body of the subject vehicle in the vehicle width direction, and the inter-vehicle distance between the subject vehicle and the third preceding vehicle is greater than the inter-vehicle distance between the subject vehicle and the first preceding vehicle when the alarm was issued by the alarm unit in situation 1. Situation 3 (b): When the third preceding vehicle rotates its direction of travel by 20 degrees to the right and the right end of the vehicle's body is to the right of the left end of the third preceding vehicle's body and to the left of the center position of the third preceding vehicle's body in the width direction, the inter-vehicle distance between the vehicle and the third preceding vehicle becomes the same as the inter-vehicle distance between the vehicle and the first preceding vehicle when the alarm was issued by the alarm unit in situation 1.

[0016] In the above configuration, in the warning control, when the host vehicle is traveling straight on a road without white lines at a vehicle speed V3 equal to the relative speed between the host vehicle and the second leading vehicle in situation 1, and a fourth leading vehicle is stopped sideways to the direction of travel of the host vehicle at a position extending from the center line of the host vehicle in the vehicle width direction and in front of the host vehicle, the warning unit may be configured to issue a warning when the inter-vehicle distance between the host vehicle and the fourth leading vehicle becomes the same as the inter-vehicle distance between the host vehicle and the first leading vehicle when the warning unit issued a warning in situation 1.

[0017] In the above configuration, in calculating the change over time of the relative position, a movement vector may be obtained from the difference in detection coordinates of objects around the vehicle in multiple images captured by the monocular camera, or the movement vector may be obtained by optical flow.

[0018] According to the FCW device for a saddle-riding type vehicle and the FCW method for a saddle-riding type vehicle of the present disclosure, it is possible to provide an FCW device for a saddle-riding type vehicle and an FCW method for a saddle-riding type vehicle that can perform FCW control different from conventional ones.

[0019] [Saddle-riding Vehicle] A saddle-riding vehicle according to the present disclosure refers to any vehicle on which a driver sits astride a saddle. As viewed from the driver of a saddle-riding vehicle, the right-hand side is referred to as the right, the left-hand side as the left, the front as the front, and the rear as the rear. The term "host vehicle" used in this disclosure refers to a saddle-riding vehicle. Saddle-riding vehicles include motorcycles. A saddle-riding vehicle includes at least one front wheel and at least one rear wheel. For example, a saddle-riding vehicle may have two front wheels and one or two rear wheels, or one front wheel and one or two rear wheels. A saddle-riding vehicle may have steered front wheels or steered rear wheels. A saddle-riding vehicle travels by driving drive wheels with a drive source. The drive source may be an internal combustion engine, an electric motor, or a hybrid drive source including an engine and an electric motor.

[0020] [FCW Device for Straddle-Type Vehicle] The FCW device for a saddle-type vehicle described in the present disclosure includes an alarm unit, one or more control units, and a monocular camera.

[0021] [White Lines] The white lines described in this disclosure refer to lines drawn on roads to indicate the vehicle's travel lane, and are not intended to be limited to a specific color. For example, the lines may be drawn in other colors, such as yellow. Such road lines may also be called outer roadway lines, shoulder strips, diagonal boundary lines, or dividing lines. The FCW device can perform FCW control without detecting white lines. In this disclosure, when a description is made that the vehicle is traveling on a road without white lines, this indicates that FCW control can be performed even on roads without white lines, and is not intended to limit the roads on which saddle-type vehicles travel to roads without white lines.

[0022] [Situation] In this disclosure, situations described with numbers, such as "Situation 1," indicate examples of situations in which the operation of the FCW device can be confirmed. One of the characteristics of the FCW device is that it performs processes such as detecting the position of objects around the vehicle and predicting the vehicle's path, and can change whether or not to issue an alarm depending on the situation. Each situation described with a number indicates that the alarm control performed by the FCW device can be confirmed by recreating this situation, and it is not intended to limit the operation of the FCW device to the described situation.

[0023] [Warning Unit] The warning unit described in the present disclosure is a warning device that issues a warning to at least the driver of a saddle-riding type vehicle. The warning unit issues a warning targeting at least one of the auditory, visual, and tactile senses. A warning targeting the auditory sense may be issued by emitting a voice or warning sound from a speaker. A warning targeting the visual sense may be issued by displaying information on a display device or illuminating a light-emitting device. Warning devices such as speakers, display devices, and light-emitting devices may be installed, for example, on or near the handlebars. If the driver wears a helmet, the warning device may be mounted on the helmet. Devices such as a speedometer and a navigation device provided in the saddle-riding type vehicle may be used as warning devices. A warning targeting the tactile sense may be issued by vibrating at least one of the handlebars, helmet, and seat.

[0024] [Control Unit] The control unit described in the present disclosure controls each unit constituting the FCW device. The control unit controls each unit to realize the functions and operations of the FCW device described in the present disclosure. The control unit is a control device that executes FCW control. FCW control includes host vehicle path prediction, host vehicle peripheral object position detection, and warning control. The FCW device may include multiple control units, and multiple processes may be executed in parallel by separate control units. For example, a process related to host vehicle path prediction and a process related to host vehicle peripheral object position detection may be executed in parallel simultaneously. The control unit calculates a numerical value indicating the likelihood of a collision between the host vehicle and the object based on the host vehicle path prediction result and the host vehicle peripheral object position detection result. For example, the time to collision (TTC) may be used as the numerical value indicating the likelihood of a collision. Furthermore, the numerical value indicating the likelihood of a collision may be, for example, the distance between the leaning vehicle and the object or the relative movement speed. The control unit determines whether an alarm is necessary and when to issue the alarm based on the possibility of a collision, and executes alarm control to issue an alarm from the alarm device based on the determination result. The control unit can execute alarm control continuously while the saddle-riding type vehicle is traveling, regardless of whether the saddle-riding type vehicle is traveling straight or turning. A program corresponding to the control unit is prepared in advance in a non-volatile storage device, and the function and operation of the control unit are realized by executing this program by predetermined hardware. The control unit may be realized by an ECU (Electronic Control Unit) for vehicle control, or the FCW device may have a dedicated control unit.

[0025] [Monocular Camera] The monocular camera described in the present disclosure is an imaging device that captures images of the periphery of a saddle-riding vehicle. The FCW device can perform FCW control using a single monocular camera, which is smaller than a stereo camera. The monocular camera is fixed to the saddle-riding vehicle and used. The monocular camera can capture images of the area ahead of the road on which the saddle-riding vehicle is traveling. The monocular camera captures images of preceding vehicles traveling ahead of the saddle-riding vehicle while the saddle-riding vehicle is traveling straight or turning, vehicles stopped or parked in front of the saddle-riding vehicle, and other obstacles. The preceding vehicles captured by the monocular camera include vehicles traveling on a predicted path obtained by predicting the vehicle's path and vehicles traveling at a position deviating from the predicted path. The monocular camera captures moving images or continuously captures still images, thereby continuously capturing images of objects around the saddle-riding vehicle.

[0026] [Vehicle Path Prediction] The vehicle path prediction described in the present disclosure is a process for predicting the path of the vehicle. Vehicle path prediction also includes predicting the path on an image captured by a monocular camera. Note that predicting the path on the captured image may be performed by mapping the predicted path of the vehicle in three-dimensional coordinates in the real world onto corresponding planar coordinates on the captured image. Planar coordinates on the captured image are, for example, an orthogonal coordinate system with the center of the captured image as the origin. When the saddle-riding vehicle is traveling straight, the FCW device can predict the path of the saddle-riding vehicle on the image captured by the monocular camera based on the mounting position, mounting angle, imaging direction, imaging range, etc. of the monocular camera on the saddle-riding vehicle. When the saddle-riding vehicle is turning, the FCW device can predict a curved path as the path of a lean vehicle turning based on the detection result by the turning state detection unit. When the saddle riding type vehicle is turning, the FCW device can also predict the path of the turning saddle riding type vehicle by curvature correcting the predicted path on the captured image, which is obtained assuming that the saddle riding type vehicle is traveling straight, based on the detection result by the turning state detection unit.The FCW device can predict the path of the turning saddle riding type vehicle in approximately real time after acquiring an image by the monocular camera while the saddle riding type vehicle is traveling.

[0027] [Position Detection of Objects Surrounding the Vehicle] The position detection of objects surrounding the vehicle described in the present disclosure is a process of detecting objects around the vehicle and identifying the position of each object. The position detection of objects around the vehicle is performed using images captured by a monocular camera. Here, the position of an object may be a position on the image captured by the monocular camera. By performing image analysis to detect objects on the image captured by the monocular camera, the objects appearing in the captured image and the positions of each object are detected. This type of image analysis is sometimes referred to as object detection, object recognition, or the like. Objects detected from the captured image include a preceding vehicle traveling ahead of the saddle-riding vehicle while the vehicle is traveling straight or turning, a stopped or parked vehicle ahead, and other obstacles. The preceding vehicle detected from the captured image includes a vehicle traveling on a predicted path obtained by vehicle path prediction and a vehicle traveling at a position deviating from the predicted path. When a detected vehicle is referred to as a "preceding vehicle," it refers to a vehicle traveling ahead of the saddle-riding vehicle in the same direction as the saddle-riding vehicle. The FCW device can detect the positions of objects around the vehicle in substantially real time after capturing an image using a monocular camera while the straddle-type vehicle is traveling.

[0028] [Calculation of Time-Varying Relative Position Between Detected Object and Vehicle] The calculation of time-ary changing of the relative position between a detected object and the vehicle (relative movement analysis) described in the present disclosure calculates time-ary changing of the relative position between the vehicle and objects around the vehicle based on the results of position detection of objects around the vehicle obtained from multiple captured images taken by a monocular camera. For example, a movement vector is calculated from the difference between detected coordinates of objects around the vehicle in multiple captured images taken by the monocular camera based on the time history. Furthermore, the calculation of time-ary changing of the relative position may also calculate the movement vector using optical flow.

[0029] [Collision Likelihood] The collision likelihood described in the present disclosure is a numerical value indicating the likelihood of a collision between the saddle-riding vehicle and a nearby object. For example, the collision likelihood can be determined based on the relative movement speed of the object relative to the saddle-riding vehicle, the distance between the saddle-riding vehicle and the object, the time until the saddle-riding vehicle collides with the object, and the like. The collision likelihood is calculated based on the predicted path of the host vehicle obtained by performing host-vehicle path prediction, the position of each object obtained by performing host-vehicle peripheral object position detection, and the relative movement between each detected object and the saddle-riding vehicle. For example, the position detection of the object's peripheral object determines the distance from the detected object to the saddle-riding vehicle in the captured image. The direction and movement speed of the detected object relative to the saddle-riding vehicle are determined by comparing multiple consecutively captured images. The time until collision is determined based on the distance from the object to the saddle-riding vehicle and the relative movement speed. Alarm control is performed to determine whether and when an alarm should be issued by the alarm unit based on the result of comparing the value indicating the collision likelihood with a threshold value prepared in advance according to the type of collision likelihood. For example, when the time to collision (TTC) is used as the collision probability, a predetermined time is set as a threshold, and when the time to collision reaches the threshold time, alarm control is performed to issue an alarm.

[0030] [Passing each other just before a turning course] As described in the present disclosure, passing each other just before a turning course refers to a situation in which, when the vehicle is traveling straight and there is a turning course ahead in the path, an oncoming vehicle comes from the turning course toward the vehicle, and the oncoming vehicle is detected as a detected object ahead of the predicted path of the vehicle.

[0031] [Preceding vehicle out] In the present disclosure, the preceding vehicle out refers to a situation in which, when the host vehicle is traveling straight and there is a preceding vehicle ahead of the host vehicle's predicted path, the preceding vehicle moves to the right or left of the host vehicle's direction of travel at a predetermined angle relative to the host vehicle's direction of travel, thereby deviating from the host vehicle's predicted path.

[0032] [Hardware Configuration] The FCW device according to the present disclosure is characterized in that it performs FCW control that has not been achieved in the past. A person skilled in the art can implement the hardware configuration of the FCW device according to the present disclosure and a saddle-riding type vehicle equipped with an FCW device using the hardware configurations of devices and saddle-riding type vehicles known in prior art documents, other publicly known documents, and conventional technology. Therefore, a detailed description of the hardware configuration of the FCW device and saddle-riding type vehicle will be omitted.

[0033] [Others] In this disclosure, when a process is described as being performed "based on A" or "taking A into consideration," the process is performed using A, but the information used is not limited to A, and information other than A may also be used. In this disclosure, when "at least one" is used in conjunction with an option, this means that all possible combinations of multiple options are included. In this disclosure, when "including," "comprising," "having," and their derivatives are used, this means that other content may be included in addition to the listed content. In this disclosure, when "may" or "may" is used, this means that this is a non-exclusive example and is not limited to the described example. In this disclosure, unless the number of components is clearly specified, the number of components may be one or more. Unless otherwise defined, the terms used in this disclosure have the general meaning understood by those skilled in the art of FCW control. The FCW device according to the present disclosure is not limited to the configurations described in the following embodiments or the configurations shown in the drawings. The FCW device according to the present disclosure can be implemented by combining multiple embodiments described below. The FCW device according to the present disclosure can also be implemented in forms other than the embodiments described below, or by modifying the embodiments described below.

[0034] Fig. 1 is a diagram for explaining an overview of an FCW device for a saddle-ride type vehicle according to an embodiment of the present disclosure. Fig. 2 is a diagram for explaining the operation when a preceding vehicle is traveling ahead of the host vehicle. Fig. 3 is a diagram for explaining the operation when a preceding vehicle is traveling on a turning path ahead of the host vehicle. Fig. 4 is a diagram for explaining the operation when a preceding vehicle ahead of the host vehicle is traveling so as to deviate from the path of the host vehicle. Fig. 5 is a diagram for explaining the operation when a preceding vehicle stops ahead of the host vehicle.

[0035] An FCW device 2 for a saddle-riding type vehicle according to an embodiment of the present disclosure will be described with reference to Figures 1 to 5. As shown in Figure 1, the FCW device 2 for a saddle-riding type vehicle is provided on a saddle-riding type vehicle 1.

[0036] The FCW device 2 for a saddle-riding type vehicle includes an alarm unit 21 , one or more control units 22 , and a monocular camera 23 .

[0037] The warning unit 21 issues a warning to the driver of the saddle riding type vehicle 1. The control unit 22 predicts the path of the saddle riding type vehicle 1, i.e., the host vehicle, detects the positions of objects around the host vehicle, and analyzes the relative movement between the host vehicle and the objects around the host vehicle. The control unit 22 calculates the possibility of a collision using the results of the host vehicle path prediction, the detection of the positions of objects around the host vehicle, and the analysis of the relative movement between the host vehicle and the objects, and performs warning control to control whether or not the warning unit 21 issues a warning and the timing of issuing the warning based on the collision possibility. The FCW device 2 for a saddle riding type vehicle performs FCW control, including object position detection, host vehicle path prediction, analysis of the relative movement between the host vehicle and the objects, and warning control, as shown within the dashed line frame in Fig. 1 .

[0038] A monocular camera 23 fixed to the body of the saddle riding type vehicle 1 captures images of the surroundings of the vehicle, including the area ahead of the saddle riding type vehicle 1. The control unit 22 acquires (A) the captured image captured by the monocular camera 23. Based on the acquired captured image, the control unit 22 detects (B) the positions of objects around the vehicle and predicts (C) the path of the vehicle.

[0039] The control unit 22 performs a relative movement analysis (D) between the host vehicle and the object based on the results obtained by detecting the position of an object around the host vehicle and the results obtained by predicting the path of the host vehicle, and can execute warning control (E) in situations 1, 2, and 3 shown in FIG. 1 based on the results of the relative movement analysis between the host vehicle and the object. Here, the relative movement analysis performs object position detection around the host vehicle to obtain detected coordinates, and calculates a movement vector (direction and magnitude) from the difference between the detected coordinates in the time-series data of the obtained detected coordinates. Note that the movement vector may be calculated using the optical flow of an image captured by a monocular camera.

[0040] Situations 1, 2, and 3 shown in Figure 1 show the positional relationship between the traveling saddle-riding vehicle 1 and preceding vehicles 101-103 detected by detecting the positions of objects around the vehicle, as viewed from above, the predicted path of the saddle-riding vehicle 1 obtained by predicting the vehicle's path, and the results of a relative movement analysis between the preceding vehicle and the vehicle. The dashed-dotted line shows the predicted path of the saddle-riding vehicle 1 obtained by predicting the vehicle's path. The dashed lines show the paths that both ends of the saddle-riding vehicle 1 in the vehicle width direction will take as the saddle-riding vehicle 1 travels along the predicted path. The arrows attached to the preceding vehicles 101-103 indicate the direction of movement of the preceding vehicles. If an object is present in the band-shaped area indicated by the two dashed lines, there is a possibility that the saddle-riding vehicle 1 will collide with this object as it travels along the predicted path. Based on the analysis of the relative movement between the preceding vehicle and the vehicle itself, the control unit 22 executes warning control such that if there is a high possibility of the saddle-type vehicle 1 colliding with the preceding vehicle while traveling along the predicted course, the warning unit 21 is controlled to issue a warning, and if there is a low possibility of the saddle-type vehicle 1 colliding with the preceding vehicle, the warning unit 21 is controlled not to issue a warning.

[0041] In situation 1, while the host vehicle is traveling straight on a road without white lines at a vehicle speed V1, a first leading vehicle 101 is traveling straight in the same direction as the host vehicle at a vehicle speed V2 (V2 < V1) that is slower than the host vehicle's speed, at a position that is an extension of the vehicle's widthwise center line and ahead of the host vehicle.

[0042] In situation 1, the control unit 22 executes warning control to issue a warning when the possibility of a collision between the saddle riding type vehicle 1 and the first leading vehicle 101 reaches or exceeds a predetermined collision possibility. For example, as shown in Figure 2(a), if at time t = t1 the distance d between the saddle riding type vehicle 1 and the leading vehicle 101 is longer than the distance Da at which a warning is issued at a predetermined relative speed Vr (V1 - V2), the control unit 22 executes warning control to prevent the warning unit 21 from issuing a warning.

[0043] On the other hand, as shown in FIG. 2(b), when the distance d between the saddle-type vehicle 1 and the preceding vehicle 101 becomes equal to or shorter than Da at time t=t2 (t2>t1), the control unit 22 executes alarm control to control the alarm unit 21 to issue an alarm.

[0044] In situation 2, while the host vehicle is traveling straight at a vehicle speed V3 on a road without white lines, the second leading vehicle 102 is traveling so as to pass a position which is an extension of the center line in the vehicle width direction of the host vehicle, a position in front of the host vehicle, and a position where the inter-vehicle distance between the host vehicle and the first leading vehicle is the same as the inter-vehicle distance between the host vehicle and the first leading vehicle when the alarm was issued by the alarm unit in situation 1, at a relative speed (V2-V1) of situation 1. In addition, the movement vector of the second leading vehicle 102 in the traveling direction is at an angle of 110° with respect to the traveling direction of the host vehicle.

[0045] In situation 2, the control unit 22 executes warning control to control the warning unit 21 so as not to issue a warning for the second leading vehicle 102. For example, as shown in Figure 3(a), at time t = t1, the saddle riding type vehicle 1 is traveling straight. The second leading vehicle 102, which has come out of a turning path, is present on the predicted path of the saddle riding type vehicle 1. In this case, the distance d between the vehicle and the second leading vehicle 102 is longer than the distance Da at which a warning is issued, so the control unit 22 controls the warning unit 21 so as not to issue a warning.

[0046] As shown in Figure 3(b), at time t = t2 (t2 > t1), the distance d between the saddle riding type vehicle 1 and the second leading vehicle 102 becomes equal to or shorter than Da. In Figures 3(a) and 3(b), an analysis of the relative movement between the saddle riding type vehicle 1 and the second leading vehicle 102 obtains an analysis result indicating that the second leading vehicle 102 is traveling at a movement vector angle of 110° with respect to the traveling direction of the saddle riding type vehicle 1. Based on the obtained analysis result, the control unit 22 controls the warning unit 21 so as not to issue a warning targeting the second leading vehicle 102. That is, in Figure 3(b), the control unit 22 executes warning control so that the warning unit 21 will not issue a warning even if the second leading vehicle 102 is traveling at the same relative speed and at the same distance as when the warning was issued in situation 1.

[0047] 1 , a scenario is assumed in which the situation changes from situation 3(a) to situation 3(b) described below. In situation 3(a), the subject vehicle is traveling straight ahead at a vehicle speed V1 on a road without white lines, and the third leading vehicle 103 is located ahead of the subject vehicle on an extension of the center line in the vehicle width direction, and is traveling in the same direction as the subject vehicle at a vehicle speed V2 (V2<V1) that is slower than the vehicle speed of the subject vehicle, at a position where the right end of the third leading vehicle is positioned at the same position as the right end of the subject vehicle in the vehicle width direction. Furthermore, at this time, the distance between the subject vehicle and the third leading vehicle 103 is greater than the distance between the subject vehicle and the first leading vehicle 101 when the warning unit 21 issued a warning in situation 1.

[0048] In situation 3(b), the third leading vehicle 103 rotates its direction of travel 20 degrees to the right, and the right edge of the host vehicle's body is to the right of the left edge of the third leading vehicle 103's body and to the left of the center position of the third leading vehicle 103 in the vehicle width direction. The distance between the host vehicle and the third leading vehicle 103 is the same as the distance between the host vehicle and the first leading vehicle 101 when the warning unit 21 issued a warning in situation 1. The control unit 22 controls the warning unit 21 so as not to issue a warning in situation 3. For example, as shown in FIG. 4(a), at time t = t1, the saddle-riding type vehicle 1 is traveling straight. The third leading vehicle 103 is traveling on the predicted path of the saddle-riding type vehicle 1, with its movement vector angle forming a 20° angle with the direction of travel of the saddle-riding type vehicle 1.

[0049] On the other hand, as shown in Figure 4(b), at time t = t2 (t2 > t1), the distance d between the saddle riding type vehicle 1 and the third leading vehicle 103 becomes equal to or shorter than Da. In Figures 4(a) and 4(b), analysis of the relative movement between the saddle riding type vehicle 1 and the third leading vehicle 103 results in an analysis result indicating that the third leading vehicle 103 is traveling at a movement vector angle of 20° with the traveling direction of the saddle riding type vehicle 1. Based on the obtained analysis result, the control unit 22 executes warning control such that an alarm is not issued for the third leading vehicle 103. That is, in Figure 4(b), the control unit 22 executes warning control so that an alarm is not issued by the warning unit 21 even if the third leading vehicle 103 is traveling at the same relative speed and at the same distance as when the alarm was issued in situation 1.

[0050] Next, the operation of the FCW device for a saddle-riding type vehicle when a leading vehicle 201 is stopped in front of the saddle-riding type vehicle 1 will be described. Fig. 5 is a diagram for explaining the operation when a fourth leading vehicle 201 is present and stopped in front of the host vehicle. As shown in Fig. 5, while the host vehicle is traveling straight on a road without white lines, the fourth leading vehicle 201 is stopped in front of the host vehicle on an extension of the center line in the vehicle width direction. As shown in Fig. 5, the fourth leading vehicle 201 is stopped sideways with respect to the traveling direction of the host vehicle.

[0051] The control unit 22 executes warning control so that the warning unit 21 issues a warning when the saddle-type vehicle 1 is traveling at a vehicle speed V1-V2 and the distance d between the saddle-type vehicle 1 and the stopped fourth preceding vehicle 201 becomes equal to or shorter than Da.

[0052] In this way, the FCW device 2 for a saddle-riding vehicle predicts the path of the saddle-riding vehicle 1 and controls the warning unit 21 to issue a warning when the possibility of a collision with an object on the predicted path reaches a predetermined probability of collision. In other words, the FCW device 2 for a saddle-riding vehicle does not issue a warning for objects that are not on the predicted path. As shown in Situations 2 and 3, even when there is a leading vehicle ahead of the predicted path of the saddle-riding vehicle 1, the FCW device 2 for a saddle-riding vehicle can exclude the leading vehicle from the list of targets for warning about a forward collision based on the analysis results of the relative movement analysis between the saddle-riding vehicle 1 and the leading vehicle.

[0053] The FCW device 2 for a saddle riding type vehicle issues an alarm when an object approaching the saddle riding type vehicle 1 due to movement of the saddle riding type vehicle 1 or relative movement between the saddle riding type vehicle 1 and the object is on the predicted path of the saddle riding type vehicle 1, but does not issue an alarm when it is predicted that the object will deviate from the predicted path of the vehicle. Situations 1, 2, and 3 are examples to illustrate this, and the alarm control by the FCW device 2 for a saddle riding type vehicle is not limited to situations 1, 2, and 3.

[0054] 1 saddle-riding type vehicle 2 FCW device for saddle-riding type vehicle 21 alarm unit 22 control unit 23 monocular camera

Claims

1. An FCW device for a saddle-riding type vehicle comprising: an alarm unit which issues an alarm to a driver; and one or more control units which execute a host vehicle path prediction which predicts a path of the host vehicle and a host vehicle peripheral object position detection which detects the positions of objects around the host vehicle, calculate a possibility of a collision between the host vehicle and the object using the results of the host vehicle path prediction and the results of the host vehicle peripheral object position detection, and execute alarm control which controls whether or not an alarm is issued by the alarm unit based on the possibility of collision; the FCW device for a saddle-riding type vehicle is further provided with a monocular camera which is fixed to the host vehicle and images the surroundings of the host vehicle, wherein the control unit executes calculations of changes in the relative positions of the objects detected in the position detection of the objects around the host vehicle relative to the host vehicle in the images captured by the monocular camera, and executes the alarm control using the results of the host vehicle path prediction, the host vehicle peripheral object position detection, and the changes in the relative positions as described in each of the following situations. Situation 1: When the host vehicle is traveling straight at a vehicle speed V1 on a road without white lines, and a first preceding vehicle is traveling straight in the same direction as the host vehicle at a position extended from the vehicle width centerline of the host vehicle and in front of the host vehicle at a vehicle speed V2 (V2 < V1) that is slower than the vehicle speed of the host vehicle, the control unit executes the warning control so that the warning unit issues a warning when the possibility of a collision between the host vehicle and the first preceding vehicle reaches or exceeds a predetermined possibility of collision. Situation 2: When the host vehicle is traveling straight on a road without white lines at a vehicle speed V3, and a second preceding vehicle is passing at a position that is an extension of the center line in the vehicle width direction of the host vehicle, that is in front of the host vehicle, and that has a similar inter-vehicle distance between the host vehicle and the first preceding vehicle when the alarm was issued by the alarm unit in situation 1, at a vehicle speed such that the relative speed between the host vehicle and the second preceding vehicle is the relative speed (V2-V1) in situation 1, the control unit executes the alarm control so that the alarm unit does not issue an alarm. Situation 3: In a situation in which the relative position between the host vehicle and a third preceding vehicle changes so as to change from situation 3(a) to situation 3(b) described below, the control unit executes the alarm control so that the alarm unit does not issue an alarm.Situation 3 (a): While the host vehicle is traveling straight on a road without white lines at the vehicle speed V1, the third preceding vehicle is located ahead of the vehicle width centerline of the host vehicle, and is traveling in the same direction as the host vehicle at a vehicle speed V2 (V2 < V1) that is slower than the vehicle speed of the host vehicle, at a position where the position of the right end of the third preceding vehicle is the same as the position of the right end of the host vehicle in the vehicle width direction, and the inter-vehicle distance between the host vehicle and the third preceding vehicle is greater than the inter-vehicle distance between the host vehicle and the first preceding vehicle when the alarm was issued by the alarm unit in situation 1. Situation 3 (b): When the third preceding vehicle rotates its direction of travel by 20 degrees to the right, and the right end of the host vehicle's body is to the right of the left end of the third preceding vehicle's body and to the left of the center position of the third preceding vehicle's body in the width direction, the inter-vehicle distance between the host vehicle and the third preceding vehicle becomes the same as the inter-vehicle distance between the host vehicle and the first preceding vehicle when the alarm was issued by the alarm unit in situation 1.

2. The FCW device for a saddle-type vehicle as described in claim 1, characterized in that, when the vehicle is traveling straight on a road without white lines at a vehicle speed V3 equal to the relative speed between the vehicle and the second preceding vehicle in situation 1, and a fourth preceding vehicle is stopped sideways to the traveling direction of the vehicle at a position extended from the vehicle width direction center line of the vehicle and in front of the vehicle, the control unit executes the warning control so that the warning unit issues a warning when the inter-vehicle distance between the vehicle and the fourth preceding vehicle becomes the same as the inter-vehicle distance between the vehicle and the first preceding vehicle when the warning unit issued a warning in situation 1.

3. The FCW device for a saddle-type vehicle as described in claim 1, characterized in that, in calculating the change over time of the relative position, the control unit determines a movement vector from the difference in detection coordinates of the object around the vehicle in multiple images captured by the monocular camera, or determines the movement vector by optical flow.

4. An FCW method for a saddle-type vehicle, for an FCW device for a saddle-type vehicle, comprising a warning unit which issues a warning to a driver, and one or more control units which execute a host vehicle path prediction which predicts a path of the host vehicle, and a host vehicle peripheral object position detection which detects the positions of objects around the host vehicle, calculate a possibility of a collision between the host vehicle and the object using the results of the host vehicle path prediction and the results of the host vehicle peripheral object position detection, and execute warning control which controls whether or not a warning is issued by the warning unit based on the possibility of collision, the FCW method for a saddle-type vehicle comprising: a step of calculating a time change in the relative position of the object detected in the position detection of the host vehicle peripheral object in an image captured by a monocular camera fixed to the host vehicle for capturing an image of the surroundings of the host vehicle, relative to the host vehicle, and a step of executing the warning control using the results of the host vehicle path prediction, the host vehicle peripheral object position detection, and the time change in the relative position, as described in each of the following situations. Situation 1: When the host vehicle is traveling straight at a vehicle speed V1 on a road without white lines, and a first preceding vehicle is traveling straight in the same direction as the host vehicle at a position extended from the vehicle width centerline of the host vehicle and in front of the host vehicle at a vehicle speed V2 (V2 < V1) that is slower than the vehicle speed of the host vehicle, the control unit executes the warning control so that the warning unit issues a warning when the possibility of a collision between the host vehicle and the first preceding vehicle reaches or exceeds a predetermined collision possibility. Situation 2: When the host vehicle is traveling straight on a road without white lines at a vehicle speed V3, and a second preceding vehicle is passing at a position that is an extension of the center line in the vehicle width direction of the host vehicle, that is in front of the host vehicle, and that has a similar inter-vehicle distance between the host vehicle and the first preceding vehicle when the alarm was issued by the alarm unit in situation 1, at a vehicle speed such that the relative speed between the host vehicle and the second preceding vehicle is the relative speed (V2-V1) in situation 1, the control unit executes the alarm control so that the alarm unit does not issue an alarm. Situation 3: In a situation in which the relative position between the host vehicle and a third preceding vehicle changes to change from situation 3(a) to situation 3(b) described below, the control unit executes the alarm control so that the alarm unit does not issue an alarm.Situation 3 (a): While the host vehicle is traveling straight on a road without white lines at a vehicle speed V1, the third preceding vehicle is located ahead of the host vehicle's vehicle width direction center line, and is traveling in the same direction as the host vehicle at a vehicle speed V2 (V2 < V1) that is slower than the vehicle speed of the host vehicle, at a position where the position of the right end of the third preceding vehicle is the same as the position of the right end of the host vehicle in the vehicle width direction, and the inter-vehicle distance between the host vehicle and the third preceding vehicle is greater than the inter-vehicle distance between the host vehicle and the first preceding vehicle when the alarm was issued by the alarm unit in situation 1. Situation 3 (b): When the third preceding vehicle rotates its direction of travel by 20 degrees to the right, and the right end of the host vehicle's body is to the right of the left end of the third preceding vehicle's body and to the left of the center position of the third preceding vehicle's body in the width direction, the inter-vehicle distance between the host vehicle and the third preceding vehicle becomes the same as the inter-vehicle distance between the host vehicle and the first preceding vehicle when the alarm was issued by the alarm unit in situation 1.

5. The FCW method for a saddle-type vehicle as described in claim 4, characterized in that in the warning control, when the host vehicle is traveling straight on a road without white lines at a vehicle speed V3 equal to the relative speed between the host vehicle and the second preceding vehicle in situation 1, and a fourth preceding vehicle is stopped sideways to the traveling direction of the host vehicle at a position extended from the center line of the host vehicle in the vehicle width direction and in front of the host vehicle, an alarm is issued by the warning unit when the inter-vehicle distance between the host vehicle and the fourth preceding vehicle becomes the same as the inter-vehicle distance between the host vehicle and the first preceding vehicle when the alarm was issued by the warning unit in situation 1.

6. The FCW method for a saddle-type vehicle according to claim 4, characterized in that in calculating the change over time of the relative position, a movement vector is calculated from the difference in detection coordinates of the object around the vehicle in multiple images captured by the monocular camera, or the movement vector is calculated by optical flow.

Images