Inter-vehicle distance control device and method

Abstract

Provided is an inter-vehicle distance control device (100) wherein: a driving force control unit (156) starts first control for reducing a driving force of a host vehicle (1) when an inter-vehicle distance identified by a distance identification unit (152) changes from a first distance to a second distance which is shorter than the first distance, and the second distance is not more than a first control execution start distance that has been set in advance as the distance at which the first control is started; and the driving force control unit (156) further starts second control for regulating the driving force of the host vehicle (1) so as not to exceed the driving force of the host vehicle (1) corresponding to the speed of a preceding vehicle (O) identified by a speed identification unit (154), when the inter-vehicle distance that has become the second distance becomes a third distance which is shorter than the second distance, and the third distance is a second control execution start distance that has been set in advance as the distance at which the second control is started.

Description

Vehicle distance control device and method

[0001] The present invention relates to a vehicle distance control device and method.

[0002] In recent years, from the viewpoint of improving the safety of vehicles and the traffic environment in which the vehicles travel, research and development has been conducted on advanced driver-assistance systems (ADAS) having a function of assisting the driving operation of a vehicle driver. Among such advanced driver-assistance systems, for example, an adaptive cruise control (ACC) system and a forward collision warning (FCW) system monitor the vehicle speed of a host vehicle and a preceding vehicle, the inter-vehicle distance and relative vehicle speed between the host vehicle and the preceding vehicle, and the distance between the host vehicle and surrounding objects. The ACC system has a function of following the host vehicle and the preceding vehicle while maintaining a constant inter-vehicle distance, and the FCW system has a function of warning the driver of the possibility of a collision when the host vehicle gets too close to the preceding vehicle.

[0003] Under such circumstances, Patent Document 1 relates to a vehicle distance control device, and discloses a configuration in which a controller 12 calculates the actuator drive amount of an automatic braking mechanism 11 and the target throttle opening of a throttle device based on the output of a vehicle distance sensor 12 and the output 14 of a vehicle speed sensor, and controls the braking force and throttle opening.

[0004] Japanese Patent Application Publication No. 05-166099

[0005] However, according to the inventor's research, Patent Document 1 intends to reduce the burden on the automatic braking mechanism by setting the throttle opening to zero simultaneously with automatic braking when the distance between the subject vehicle and the preceding vehicle becomes narrow, and widening the distance between the vehicles by controlling the throttle opening. However, there is no disclosure or suggestion of controlling the driving force of the subject vehicle so that the distance between the vehicles reaches the set distance appropriately, and then controlling the driving force of the subject vehicle so that the distance between the vehicles is maintained appropriately at the set distance, and it is believed that there is room for improvement in this regard.

[0006] The present invention was developed based on the above considerations, and aims to provide a vehicle distance control device and method that can control the driving force of the vehicle so that the vehicle distance between the vehicle and a preceding vehicle appropriately reaches a set vehicle distance, and then control the driving force of the vehicle so that the vehicle distance is appropriately maintained at the set vehicle distance.

[0007] In order to achieve the above object, in one aspect of the present invention, there is provided an inter-vehicle distance control device comprising a distance determination unit that determines the inter-vehicle distance between a host vehicle and a preceding vehicle traveling in front of the host vehicle, a speed determination unit that determines the speed of the preceding vehicle, and a driving force control unit that controls the driving force of the host vehicle, wherein the driving force control unit initiates the first control to reduce the driving force of the host vehicle when the inter-vehicle distance determined by the distance determination unit changes from a first distance to a second distance that is shorter than the first distance and the second distance is equal to or shorter than a first control execution start distance that is preset as a distance at which a first control is to be initiated, and the driving force control unit further initiates the second control to restrict the driving force of the host vehicle so that it does not exceed the driving force of the host vehicle that corresponds to the speed of the preceding vehicle determined by the speed determination unit when the inter-vehicle distance determined by the distance determination unit becomes a third distance that is shorter than the second distance and the third distance is a second control execution start distance that is preset as a distance at which a second control is to be initiated.

[0008] According to the inter-vehicle distance control device of one aspect of the present invention described above, the driving force control unit initiates a first control to reduce the driving force of the host vehicle when the inter-vehicle distance determined by the distance determination unit changes from a first distance to a second distance shorter than the first distance, and the second distance is equal to or shorter than a first control execution start distance that is preset as the distance at which the first control is to be initiated; and when the inter-vehicle distance that has become the second distance becomes a third distance shorter than the second distance, and the third distance is the second control execution start distance that is preset as the distance at which the second control is to be initiated, the driving force control unit initiates a second control to restrict the driving force of the host vehicle so that it does not exceed the driving force of the host vehicle that corresponds to the speed of the preceding vehicle determined by the speed determination unit.Therefore, after controlling the driving force of the host vehicle so that the inter-vehicle distance between the host vehicle and the preceding vehicle appropriately reaches the set inter-vehicle distance, the driving force of the host vehicle can be controlled so that the inter-vehicle distance is appropriately maintained at the set inter-vehicle distance.

[0009] Fig. 1 is a side view showing the right side of a vehicle equipped with an inter-vehicle distance control device according to an embodiment of the present invention. Fig. 2 is a schematic diagram showing the configuration of the inter-vehicle distance control device according to this embodiment. Fig. 3 is a time chart showing an example of the operation of the inter-vehicle distance control device according to this embodiment. Fig. 4 is a diagram showing the positional relationship between the host vehicle and the amount of a preceding vehicle as viewed from above, for explaining an example of the operation of the inter-vehicle distance control device according to this embodiment.

[0010] Hereinafter, a driving assistance system for a saddle-ride type vehicle according to an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the x-axis, y-axis, and z-axis form a three-axis Cartesian coordinate system, in which the x-axis direction is the longitudinal direction and direction of travel of the vehicle, with the forward direction indicated as the positive direction of the x-axis, the y-axis direction is the width direction of the vehicle, with the leftward direction indicated as the positive direction of the y-axis, and the z-axis direction is the vertical direction of the vehicle, with the upward direction indicated as the positive direction of the z-axis.

[0011] [Configuration of Vehicle] First, with reference to FIG. 1, the configuration of a vehicle to which the inter-vehicle distance control device of this embodiment is applied will be described in detail.

[0012] FIG. 1 is a side view showing the right side of a vehicle to which the following distance control device of this embodiment is applied.

[0013] As shown in FIG. 1 as a representative example of a motorcycle, which is a type of saddle-ride type vehicle, the vehicle (which may be referred to as the subject vehicle as necessary) 1 typically mainly comprises a frame member 10, which is a vehicle body framework member made of a metal such as an iron pipe, a drive source 20, which is an internal combustion engine, a steering / front suspension mechanism 30 that suspends front wheels 32, which are driven wheels, so that the vehicle can be steered, a front brake FB, a rear suspension mechanism 40 that suspends rear wheels 42, which are driven wheels, and a rear brake RB. In addition to motorcycles, the saddle-ride type vehicle may also be a small and lightweight three-wheeled or four-wheeled vehicle such as a buggy. Furthermore, the drive source 20 may be an engine, an electric motor, or a combination of an engine and an electric motor.

[0014] In more detail, the steering front suspension mechanism 30 typically includes a telescopic front fork 34 that suspends the front wheel 32 and is attached to a support member (not shown) of the frame member 10, a steering stem 36 that is attached to the support member of the frame member 10, and a handle 38 that is an operating member when steering the front wheel 32 and is fixed to the steering stem 36.

[0015] The rear suspension mechanism 40 has a swing arm 44 that is set on the frame member 10 and supports the rear wheel 42 so that it can swing freely with a predetermined geometry, using a pivot shaft (not shown) as the axis of rotation for swinging, and a rear spring / damper unit 46 that suspends the rear wheel 42.

[0016] The front brake FB is attached to the vehicle 1 as a braking mechanism for braking the front wheels 32, and the rear brake RB is attached to the vehicle 1 as a braking mechanism for braking the rear wheels 42.

[0017] The vehicle 1 also includes an imaging device 200, which is an optical unit that captures and acquires information about the vehicle's surrounding environment as images of surrounding environmental objects, an inertial measurement unit (IMU) 300 that measures the acceleration and angular acceleration of the vehicle 1, an alarm A that notifies the driver of the vehicle 1 of predetermined notification information through the driver's vision, hearing, etc., a crank angle sensor S1 that detects the rotation angle of a crankshaft (not shown) when the drive source 20 is an engine, a vehicle speed sensor S2 that detects the speed of the vehicle 1 from the rotation speed of an output shaft of a transmission (not shown) of the vehicle 1, and an accelerator opening sensor S3 that detects the opening amount (accelerator opening amount: drive operation amount) of an accelerator grip that is an accelerator operating member attached to a steering wheel 38 of the vehicle 1 and not shown. Note that the alarm (alert unit) A specifically refers to a screen display device, a speaker, etc. that are generally provided.

[0018] [Configuration and Operation of Inter-Vehicle Distance Control Device] Next, with further reference to FIGS. 2 to 4, the configuration and operation of the inter-vehicle distance control device in this embodiment will be described in detail.

[0019] Fig. 2 is a schematic diagram showing the configuration of the inter-vehicle distance control device according to this embodiment. Fig. 3 is a time chart showing an example of the operation of the inter-vehicle distance control device according to this embodiment. Fig. 4 is a diagram showing the positional relationship between the host vehicle and a preceding vehicle from a top view, for explaining an example of the operation of the inter-vehicle distance control device according to this embodiment. In Fig. 4, the position of the host vehicle is indicated by a single circle, and the position of the preceding vehicle is indicated by a double circle.

[0020] As shown in FIG. 2 , the inter-vehicle distance control device 100 is typically mounted on a frame member 10 or the like shown in FIG. 1 , is mounted on the vehicle 1, and operates using a battery (not shown) as a power source. The inter-vehicle distance control device 100 is mainly composed of an ECU (Electronic Control Unit) 10, which is an arithmetic processing device including a microcomputer having a CPU (Central Processing Unit) or the like. A crank angle sensor S1, a vehicle speed sensor S2, an accelerator opening sensor S3, an image capture device 200, an inertial measurement unit 300, and the like are electrically connected to the inter-vehicle distance control device 100. The inter-vehicle distance control device 100 functions as a control device that controls the driving state of the drive source 20 by executing a control program while referring to control data based on electrical signals output from the sensors and devices, and also functions as a control device that calculates the acceleration, angular acceleration, tilt angle, etc. of the vehicle 1 to control its running state. The inter-vehicle distance control device 100 has a control unit 150 shown as a functional block. The control programs are stored in advance in a memory (not shown) and are read from the memory when they are executed. If the drive source 20 is an engine, the control unit 150 controls the operation of the spark plugs 22, the injectors 24, and the throttle valve 26, which are respectively attached to the engine, when controlling the operating state of the engine. Typically, the throttle valve 26 is connected to a drive motor of an electronically controlled throttle device (not shown), and the opening of the throttle valve 26 changes as the control unit 150 controls the operation of the drive motor to rotate the throttle valve 26.

[0021] In detail, the control unit 150, all of which are shown as functional blocks, mainly has a distance determination unit 152, a speed determination unit 154, and a driving force control unit 156, and may further include a notification control unit 158, a driving lane discrimination unit 162, a sign detection unit 164, and an operation amount detection unit 166.

[0022] The distance determination unit 152 indicates imaging information, typically including parallax, obtained by imaging the environment of the host vehicle 1, including the preceding vehicle O of the host vehicle 1, using the imaging device 200. The distance determination unit 152 calculates the distance between the position of the host vehicle 1 and the position of the preceding vehicle O based on the electrical signal output from the imaging device 200, and determines the calculated distance as the inter-vehicle distance (sometimes simply referred to as inter-vehicle distance) between the position of the host vehicle 1 and the position of the preceding vehicle O. The distance determination unit 152 can also calculate the distance between the position of the host vehicle 1 and the position of an edge of a roadway or the position of an outer edge of an object in the environment based on the electrical signal output from the imaging device 200, and determine the calculated distance as the distance between the position of the host vehicle 1 and the position of the edge or outer edge of an object such as a roadway. The distance determination unit 152 can also determine the distance to a portion of the preceding vehicle O or an object other than the edge or outer edge. The imaging device (imaging unit) 200 is an optical unit, typically a camera, but devices other than cameras can be used as long as they are capable of capturing images of the environment, including the roadway along which the vehicle 1 is traveling and objects, within a predetermined imaging range. When a camera is used as the imaging device 200, a stereo camera that can obtain imaging information with parallax is more preferable than a monocular camera. If the imaging data contains optical disturbance components such as flicker, a filter value such as an average value of the imaging data may be referenced. Furthermore, the distance determination unit 152 can determine the distance to the vehicle 1 based not only on the imaging information from the imaging device 200, but also on location information from a GPS (Global Positioning System) or environmental information from a navigation system.

[0023] The speed identification unit 154 identifies the speed of the preceding vehicle O from the change over time in the inter-vehicle distance identified by the distance identification unit 152 and the speed of the host vehicle 1 calculated by the control unit 150 based on the electrical signal output from the vehicle speed sensor S2. Note that the speed of the preceding vehicle O may be the relative speed of the preceding vehicle O with respect to the host vehicle 1. Furthermore, the speed identification unit 154 can identify the speed of the preceding vehicle O based not only on the imaging information from the imaging device 200 but also on speed detection information from a radar device or the like.

[0024] The driving force control unit 156 determines whether the inter-vehicle distance determined by the distance determination unit 152 changes from the first distance to a second distance shorter than the first distance, and whether the second distance is less than or equal to the first control execution start distance (inter-vehicle distance control execution start distance) that is preset as the distance at which the first control is to be started, and when the second distance is less than or equal to the inter-vehicle distance control execution start distance, starts the first control, which is a first driving force control process that reduces the driving force of the host vehicle 1. Furthermore, when the inter-vehicle distance specified by the distance specifying unit 152 becomes the second distance, which is a third distance shorter than the second distance, and the third distance is a second control execution start distance (set inter-vehicle distance) previously set as the distance at which the second control is to be started, the driving force control unit 156 starts the second control, which is a second driving force control process that restricts the driving force of the host vehicle 1, by restricting the driving force requested by the driver of the host vehicle 1 so that the driving force of the host vehicle 1 does not exceed the driving force corresponding to the speed of the preceding vehicle O specified by the speed specifying unit 154. Therefore, after controlling the driving force of the host vehicle 1 so that the inter-vehicle distance between the host vehicle 1 and the preceding vehicle O appropriately reaches the set inter-vehicle distance, it is possible to control the driving force of the host vehicle 1 so that the inter-vehicle distance is appropriately maintained at the set inter-vehicle distance. When the driving source 20 is an engine, it is preferable that the driving force control unit 156 control the driving force of the host vehicle 1 by adjusting the throttle opening of the host vehicle 1, from the viewpoint of appropriately controlling the driving force while suppressing unnecessary effects on the characteristics of the engine. If the drive source 20 is an electric motor, the drive current and the like are adjusted according to the type of electric motor to control the drive force of the host vehicle 1. Furthermore, with regard to the timing to start the second control, in order to prevent the inter-vehicle distance from falling below the second control execution start distance (set inter-vehicle distance), the second control may be started when the inter-vehicle distance is equal to the second control execution start distance plus a predetermined distance (a set added inter-vehicle distance obtained by adding a predetermined value to the value of the set inter-vehicle distance).

[0025] In addition, from the viewpoint of reducing the driving force by a predetermined amount per unit time to prevent unnecessary posture changes in the vehicle 1, it is preferable that the driving force control unit 156 continues to reduce the driving force in the first control until the inter-vehicle distance changes from the second distance to the third distance.

[0026] In addition, from the viewpoint of suppressing excessive reduction in the inter-vehicle distance during the second control, it is preferable that the driving force control unit 156 reduces the driving force so that the inter-vehicle distance becomes the third distance when the inter-vehicle distance becomes a fourth distance that is shorter than the third distance after starting the second control.

[0027] In addition, from the viewpoint of suppressing excessive reduction in the inter-vehicle distance during the second control, it is preferable that the driving force control unit 156 reduces the driving force so that the speed of the host vehicle 1 becomes the second speed when the speed of the preceding vehicle O decreases from the first speed to a second speed lower than the first speed after starting the second control.

[0028] In addition, from the viewpoint of continuing to execute the second control even when the preceding vehicle O is lost, it is preferable that when the speed of the preceding vehicle O is not identified in the second control, the driving force control unit 156 regulates the driving force of the subject vehicle 1 so that it does not exceed the driving force corresponding to the speed of the preceding vehicle O identified in the control processing at the control cycle with the calculation timing immediately before that.

[0029] The notification control unit 158 ​​executes notification control, which is a control process for controlling the alarm A that notifies the driver of the vehicle 1 of information, from the viewpoint of urging the driver of the vehicle 1 to perform an operation to suppress a decrease in the inter-vehicle distance. In detail, the notification control unit 158 ​​starts the notification control when the inter-vehicle distance becomes a fifth distance that is longer than the first distance and the fifth distance is equal to or less than a fifth distance that is preset as a distance at which notification control starts.

[0030] In addition, in situations where the driver is exposed to the vehicle 1, such as in a saddle-type vehicle, the notification control unit 158 ​​preferably controls the alarm A in the notification control and notifies the driver of information by varying the driving force of the vehicle 1, in order to more reliably notify the driver that the distance between the vehicles is narrowing by generating periodic vibrations in the vehicle 1.

[0031] The driving lane discrimination unit 162 determines whether the host vehicle 1 and the preceding vehicle O are traveling in the same lane based on the electrical signal output from the imaging device 200. At this time, from the viewpoint of avoiding determining that a vehicle traveling in an adjacent lane is the preceding vehicle O, it is preferable that the driving force control unit 156 executes the first control and the second control when the driving lane discrimination unit 162 determines that the host vehicle 1 and the preceding vehicle O are traveling in the same lane.

[0032] The sign detection unit 164 detects road signs (not shown) that are present ahead of the host vehicle 1 based on the electrical signal output from the imaging device 200. At this time, from the viewpoint of realizing a vehicle-to-vehicle distance that corresponds to information such as the speed limit indicated by the road sign, it is preferable that the driving force control unit 156 executes a second control that restricts the driving force of the host vehicle 1 so that the driving force does not exceed the driving force corresponding to the lower of the speed limit indicated by the road sign detected by the sign detection unit 164 and the speed of the preceding vehicle O.

[0033] The operation amount detection unit 166 detects the accelerator opening (driving operation amount) of the driver of the vehicle 1 based on the electrical signal output from the accelerator opening sensor S3.

[0034] Here, an example of the operation of the vehicle distance control device 100 will be explained using an example configuration in which an engine is used as the driving source 20, the notification control unit 158 ​​executes the notification control before the first control and the second control are executed by the driving force control unit 156, and when the first control and the second control are executed, the driving lane discrimination unit 162 determines whether the vehicle 1 and the preceding vehicle O are traveling in the same lane.

[0035] 3 , the control processing of the inter-vehicle distance control device 100 includes a notification control processing and a driving force control processing, which are started when an ignition switch (not shown) is turned on, the engine speed of the host vehicle 1 is equal to or greater than a lower limit engine speed, and the speed of the host vehicle 1 is equal to or greater than a lower limit vehicle speed, and are repeatedly executed at predetermined control intervals. The notification control processing and the driving force control processing may be terminated when the ignition switch is turned off, or when the driving force control unit 156 or the notification control unit 158 ​​determines that the driver of the host vehicle 1 has operated the brakes for a predetermined period of time or more, or that the driver of the host vehicle 1 has opened the accelerator pedal at a predetermined opening or greater for a predetermined period of time. While the ignition switch is on, the distance determination unit 152 determines the inter-vehicle distance between the host vehicle 1 and the preceding vehicle O, and the speed determination unit 154 determines the speed of the preceding vehicle O.

[0036] Up until time t1, the host vehicle 1 is approaching the preceding vehicle O, and the distance between the vehicles is decreasing. Note that, although the preceding vehicle O is illustrated as traveling at a constant speed v1, there is a certain degree of variation in the speed depending on the operation of the driver of the preceding vehicle O and the functions of the preceding vehicle O, and there is a similar variation in the speed of the host vehicle 1.

[0037] At time t1, the inter-vehicle distance becomes equal to or less than the inter-vehicle distance control execution start distance, and the notification control unit 158 ​​determines that the inter-vehicle distance has changed from a distance greater than the inter-vehicle distance control execution start distance to a distance equal to or less than the inter-vehicle distance control execution start distance. In response to this, the notification control unit 158 ​​starts notification control to control the alarm A to notify the driver of the host vehicle 1. At the same time, the notification control unit 158 ​​switches the target opening of the throttle valve 26 from the driver-requested target opening corresponding to the accelerator opening detected by the operation amount detection unit 166 to the notification control target opening. That is, the notification control unit 158 ​​causes the alarm device A to issue a notification that the inter-vehicle distance is decreasing and the host vehicle 1 is approaching the preceding vehicle O, and at the same time, the notification control unit 158 ​​intermittently decreases the value of the notification control target opening from the value of the driver-requested target opening, setting it to exhibit a time-series change in the shape of a so-called ramp burst, for example, and feedback-controls the opening and closing operation of the throttle valve 26 to periodically vibrate the drive source 20 so that the throttle opening (actual throttle opening) exhibits a time-series change in the shape of a ramp burst (the maximum value is indicated by TH1 and the minimum value is indicated by TH2), thereby executing a notification control process to issue a notification that the inter-vehicle distance is decreasing and the host vehicle 1 is approaching the preceding vehicle O. Accordingly, the engine speed of the host vehicle 1 decreases from NE1 to NE2, and the speed of the host vehicle 1 decreases from v2 to v3. The value of the inter-vehicle distance control execution start distance is predetermined according to the speed of the host vehicle 1, converted into data, and stored in memory, and the notification control unit 158 ​​reads and uses the data from memory. The value of the notification control target opening that changes over time is also predetermined according to the speed of the host vehicle 1, converted into data, and stored in memory, and the notification control unit 158 ​​reads and uses the data from memory. The length of time for which the notification control unit 158 ​​executes the notification control process is also predetermined according to the speed of the host vehicle 1, converted into data, and stored in memory, and the notification control unit 158 ​​reads and uses the data from memory. In addition, in the notification control process by the notification control unit 158, priority may be given to the notification that periodically vibrates the drive source 20, and the notification by the alarm A may be omitted.

[0038] At time t2, the notification control unit 158 ​​determines that the time period for executing the notification control process has elapsed, and the notification control process by the notification control unit 158 ​​ends. The driving lane discrimination unit 162 determines whether the host vehicle 1 and the preceding vehicle O are traveling in the same lane, based on the electrical signal output from the imaging device 200. Specifically, as shown in Fig. 4 as an example, the driving lane discrimination unit 162 determines that the host vehicle 1 and the preceding vehicle O are traveling in the same lane when a host vehicle reference line 1L passing in the fore-and-aft direction through the position of the host vehicle 1, illustrated by a single circle, overlaps with an area B (illustrated as the vehicle width area of ​​the preceding vehicle O) having widths indicated by w on both sides of a preceding vehicle reference line OL passing in the fore-and-aft direction through the position of the preceding vehicle O, illustrated by a double circle. On the other hand, if the host vehicle reference line 1L' does not overlap with area B, for example, if the host vehicle 1' is traveling in an adjacent lane across a white line CL or its extension CL', the driving lane discrimination unit 162 determines that the host vehicle 1' and the preceding vehicle O are not traveling in the same lane. Next, if the driving lane discrimination unit 162 determines that the host vehicle 1' and the preceding vehicle O are traveling in the same lane, the driving force control unit 156 starts a first driving force control process (first control) while applying the inter-vehicle distance control target opening as the target opening of the throttle valve 26 so that the inter-vehicle distance becomes the set inter-vehicle distance. Specifically, the driving force control unit 156 reduces the driving force of the host vehicle 1 by reducing the throttle opening so that the inter-vehicle distance becomes the set inter-vehicle distance while typically maintaining a constant decrease in the inter-vehicle distance per unit time. The set inter-vehicle distance value is determined in advance, converted into data, and stored in memory, with the driving force control unit 156 reading and using the data from memory. Alternatively, instead of the set inter-vehicle distance value, a set additional inter-vehicle distance value obtained by adding a predetermined value to the set inter-vehicle distance value may be used so that the inter-vehicle distance is not shorter than the set inter-vehicle distance. The set additional inter-vehicle distance value is determined in advance in accordance with the speed of the vehicle 1, converted into data, and stored in memory, with the driving force control unit 156 reading and using the data from memory. In this case, the driving force control unit 156 may read the data for the set inter-vehicle distance value or the set additional inter-vehicle distance value from memory and present it to the driver of the vehicle 1, allowing the driver to select a desired value from the presented multiple values.In addition, if the notification control processing by the notification control unit 158 ​​during the period from time t1 to time t2 is omitted, if the driving lane discrimination unit 162 determines at time t2 that the host vehicle 1 and the preceding vehicle O are traveling in the same lane, the driving force control unit 156 determines that the inter-vehicle distance has changed from a distance longer than the inter-vehicle distance control execution start distance to a distance equal to or shorter than the inter-vehicle distance control execution start distance, and in response, the driving force control unit 156 switches the target opening of the throttle valve 26 from the driver-requested target opening to the inter-vehicle distance control target opening, and the driving force control unit 156 starts the first driving force control processing (first control) so that the inter-vehicle distance becomes the set inter-vehicle distance.

[0039] At time t3, the driving force control unit 156 determines that the inter-vehicle distance matches the set inter-vehicle distance (or set added inter-vehicle distance), terminates the first driving force control process, and starts the second driving force control process (second control) to maintain the inter-vehicle distance at the set inter-vehicle distance. Specifically, while applying the driver-requested target opening as the target opening of the throttle valve 26, if the driving force control unit 156 determines that the inter-vehicle distance has become shorter than the set inter-vehicle distance or that the speed of the preceding vehicle O has decreased below v1, the driving force control unit 156 reduces the actual throttle opening so that the actual throttle opening does not exceed the vehicle speed restriction opening by reducing the driver-requested target opening so that the driver-requested target opening does not exceed the vehicle speed restriction opening, thereby reducing the driving force of the host vehicle 1. On the other hand, if the driving force control unit 156 determines that the inter-vehicle distance has become longer than the set inter-vehicle distance or that the speed v1 of the preceding vehicle O has increased, the driving force control unit 156 increases the driver-requested target opening within a range in which the driver-requested target opening does not exceed the vehicle speed restriction opening, thereby increasing the actual throttle opening within a range in which the actual throttle opening does not exceed the vehicle speed restriction opening, thereby increasing the driving force of the host vehicle 1. Here, when increasing or decreasing the vehicle speed limit opening degree, the amount of change per unit time of the increase or decrease may be set according to the relative speed between the host vehicle 1 and the preceding vehicle O. If, during the execution of the current second driving force control process, a situation occurs in which image data of the preceding vehicle O cannot be obtained, the inter-vehicle distance cannot be calculated, or the speed of the preceding vehicle O cannot be calculated, and the driving force control unit 156 is unable to determine the speed of the preceding vehicle O and, so to speak, loses sight of the preceding vehicle O, it is preferable to apply the value of the vehicle speed limit opening degree in the previous second driving force control process to the value of the vehicle speed limit opening degree in the current or subsequent second driving force control process and continue the second driving force control process. Furthermore, in such a case in which the speed of the preceding vehicle O cannot be determined and, so to speak, loses sight of the preceding vehicle O, if the driving force control unit 156 determines that the value of the driver-requested target opening degree has fallen below the value of the vehicle speed limit opening degree, the second driving force control process may be terminated, prioritizing the driver's intention to decelerate.

[0040] As is clear from the above explanation, in the first aspect of the inter-vehicle distance control device 100 in this embodiment, the driving force control unit 156 starts a first control to reduce the driving force of the host vehicle 1 when the inter-vehicle distance determined by the distance determination unit 152 changes from the first distance to a second distance shorter than the first distance, and the second distance is equal to or shorter than the first control execution start distance that is preset as the distance at which the first control is to be started; and when the inter-vehicle distance that has become the second distance becomes a third distance shorter than the second distance, and the third distance is the second control execution start distance that is preset as the distance at which the second control is to be started, the driving force control unit 156 starts a second control to restrict the driving force of the host vehicle 1 so that the driving force does not exceed the driving force of the host vehicle 1 that corresponds to the speed of the preceding vehicle O determined by the speed determination unit 154.Therefore, after controlling the driving force of the host vehicle 1 so that the inter-vehicle distance between the host vehicle 1 and the preceding vehicle O appropriately reaches the set inter-vehicle distance, the driving force of the host vehicle 1 can be controlled so that the inter-vehicle distance is appropriately maintained at the set inter-vehicle distance.

[0041] In addition, in the second phase of the inter-vehicle distance control device 100 in this embodiment, in addition to the first phase, the driving force control unit 156 continues to reduce the driving force of the host vehicle 1 during the first control until the inter-vehicle distance changes from the second distance to the third distance, thereby reducing the driving force of the host vehicle 1 by a predetermined amount per unit time, thereby preventing unnecessary posture changes in the host vehicle 1.

[0042] Furthermore, in the third phase of the inter-vehicle distance control device 100 in this embodiment, in addition to the first or second phase, when the inter-vehicle distance becomes a fourth distance, which is shorter than the third distance, after the driving force control unit 156 starts the second control, the driving force of the host vehicle 1 is reduced so that the inter-vehicle distance becomes the third distance, thereby preventing excessive reduction in the inter-vehicle distance.

[0043] Furthermore, in the fourth aspect of the inter-vehicle distance control device 100 in this embodiment, in addition to the third aspect, when the speed of the preceding vehicle O decreases from the first speed to a second speed lower than the first speed after the driving force control unit 156 starts the second control, the driving force of the host vehicle 1 is reduced so that the speed of the host vehicle 1 becomes the second speed, thereby preventing excessive reduction in the inter-vehicle distance.

[0044] In addition, in the fifth aspect of the vehicle distance control device 100 of this embodiment, in addition to the third aspect, when the speed of the preceding vehicle O is not identified in the second control, the driving force control unit 156 regulates the driving force of the vehicle 1 by regulating the driving force requested by the driver of the vehicle 1 so that it does not exceed the driving force corresponding to the speed of the preceding vehicle O identified immediately before.Therefore, the second control can be continued even if the preceding vehicle O is lost.

[0045] Furthermore, in a sixth aspect of the inter-vehicle distance control device 100 of this embodiment, in addition to the fifth aspect, it further includes an operation amount detection unit 166 that detects the amount of driving force operation by the driver of the vehicle 1, and the driving force control unit 156 terminates the second control when the driving force corresponding to the driving force operation amount detected by the operation amount detection unit 166 becomes smaller than the driving force corresponding to the speed of the preceding vehicle O, so that driving operation of the vehicle 1 based on the driver's intention can be prioritized.

[0046] Furthermore, in a seventh aspect of the inter-vehicle distance control device 100 of this embodiment, in addition to any one of the first to sixth aspects, it further includes a notification control unit 158 ​​that executes notification control to notify the driver of the vehicle 1 of information, and the notification control unit 158 ​​starts notification control when the inter-vehicle distance becomes a fifth distance that is longer than the first distance and the fifth distance is equal to or less than a distance that is preset as the distance at which notification control is to be started, thereby urging the driver of the vehicle 1 to perform an operation to suppress a decrease in the inter-vehicle distance.

[0047] Furthermore, in the eighth aspect of the inter-vehicle distance control device 100 in this embodiment, in addition to the seventh aspect, the notification control unit 158 ​​notifies the driver of the vehicle 1 of information by varying the driving force during notification control, so that in a situation where the driver is exposed from the vehicle 1, such as in a saddle-type vehicle, periodic vibrations are generated in the vehicle 1, thereby more reliably notifying the driver that the inter-vehicle distance is narrowing.

[0048] Furthermore, in the ninth aspect of the inter-vehicle distance control device 100 of this embodiment, in addition to any of the first to eighth aspects, it further includes a driving lane discrimination unit 162 that determines whether the host vehicle 1 and the preceding vehicle O are traveling in the same lane, and the driving force control unit 156 executes the first control and the second control when the driving lane discrimination unit 162 determines that the host vehicle 1 and the preceding vehicle O are traveling in the same lane, thereby making it possible to avoid determining that a vehicle traveling in an adjacent lane is the preceding vehicle O.

[0049] Furthermore, in a tenth aspect of the inter-vehicle distance control device 100 of this embodiment, in addition to any of the first to ninth aspects, it further includes a sign detection unit 164 that detects road signs present ahead of the host vehicle 1, and the driving force control unit 156 executes a second control that restricts the driving force of the host vehicle 1 so that the driving force does not exceed the driving force corresponding to the lower of the speed limit indicated by the road sign detected by the sign detection unit 164 and the speed of the preceding vehicle O identified by the speed identification unit 154, thereby making it possible to achieve an inter-vehicle distance that corresponds to information such as the speed limit indicated by the road sign.

[0050] Furthermore, in an eleventh aspect of the vehicle distance control device 100 in this embodiment, in addition to any one of the first to tenth aspects, the driving force control unit 156 controls the driving force of the vehicle 1 by adjusting the throttle opening of the vehicle 1, so that when the driving source 20 is an engine, the driving force can be appropriately controlled while suppressing unnecessary effects on its characteristics.

[0051] In addition, in another aspect of the present embodiment, the method for controlling inter-vehicle distance includes a distance specifying step for specifying the inter-vehicle distance between the host vehicle 1 and a preceding vehicle O traveling ahead of the host vehicle, a speed specifying step for specifying the speed of the preceding vehicle O, and a driving force control step for controlling the driving force of the host vehicle 1. In the driving force control step, when the inter-vehicle distance specified in the distance specifying step changes from a first distance to a second distance shorter than the first distance and the second distance is equal to or shorter than a first control execution start distance preset as a distance at which the first control is to be started, the first control for reducing the driving force of the host vehicle 1 is started, and in the driving force control unit step, the inter-vehicle distance which has become the second distance is further specified as a second distance. When the third distance becomes a third distance shorter than the distance from the preceding vehicle O, and the third distance is the second control execution start distance that is preset as the distance at which the second control is to be started, the second control is started to regulate the driving force of the subject vehicle 1 by regulating the driving force requested by the driver of the subject vehicle 1 so that it does not exceed the driving force of the subject vehicle 1 that corresponds to the speed of the preceding vehicle O identified in the speed identification process.Therefore, as with the inter-vehicle distance control device 100 of the first aspect, after controlling the driving force of the subject vehicle 1 so that the inter-vehicle distance between the subject vehicle 1 and the preceding vehicle O appropriately reaches the set inter-vehicle distance, the driving force of the subject vehicle 1 can be controlled so that the inter-vehicle distance is appropriately maintained at the set inter-vehicle distance.

[0052] It should be noted that the present invention is not limited to the above-described embodiment in terms of the type, shape, arrangement, number, etc. of the components, and it goes without saying that such modifications can be made as appropriate within the scope of the gist of the invention, such as by appropriately replacing the components with components that achieve equivalent effects.

[0053] As described above, the present invention can provide a vehicle distance control device and method that can control the driving force of the vehicle so that the vehicle distance between the vehicle and a preceding vehicle reaches a set vehicle distance, and then control the driving force of the vehicle so that the vehicle distance is maintained at the set vehicle distance.Due to its general-purpose and universal nature, it is expected that the present invention can be widely applied to driving assistance systems for motorcycles, automobiles, etc.

[0054] DESCRIPTION OF SYMBOLS 1...Vehicle 10...Frame member 20...Drive source 22...Spark plug 24...Injector 26...Throttle valve 30...Steering / front suspension mechanism 32...Front wheel 34...Telescopic front fork 36...Steering stem 38...Handle 40...Rear suspension mechanism 42...Rear wheel 44...Swing arm 46...Rear damper / spring unit 100...Inter-vehicle distance control device 150...Control unit 152...Distance determination unit 154...Speed ​​determination unit 156...Driving force control unit 158...Notification control unit 162...Travel lane discrimination unit 164...Sign detection unit 166...Operation amount detection unit 200...Image capture device 300...Inertial measurement unit FB...Front brake RB...Rear brake A...Alarm S1...Crank angle sensor S S2...Vehicle speed sensor S3...Accelerator opening sensor

Claims

1. A vehicle-to-vehicle distance control device comprising: a distance determination unit that determines the inter-vehicle distance between a host vehicle and a preceding vehicle traveling in front of the host vehicle; a speed determination unit that determines the speed of the preceding vehicle; and a driving force control unit that controls the driving force of the host vehicle, wherein the driving force control unit initiates the first control to reduce the driving force of the host vehicle when the inter-vehicle distance determined by the distance determination unit changes from a first distance to a second distance shorter than the first distance, and the second distance is equal to or shorter than a first control execution start distance that is preset as a distance at which a first control is to be initiated; and the driving force control unit further initiates the second control to restrict the driving force of the host vehicle so that it does not exceed the driving force of the host vehicle corresponding to the speed of the preceding vehicle determined by the speed determination unit, when the inter-vehicle distance determined by the distance determination unit becomes a third distance shorter than the second distance, and the third distance is a second control execution start distance that is preset as a distance at which a second control is to be initiated.

2. The inter-vehicle distance control device according to claim 1, wherein the driving force control unit, in the first control, continues to reduce the driving force until the inter-vehicle distance changes from the second distance to the third distance.

3. A vehicle-to-vehicle distance control device as described in claim 1, wherein the driving force control unit reduces the driving force so that the vehicle-to-vehicle distance becomes the third distance when the vehicle-to-vehicle distance becomes a fourth distance that is shorter than the third distance after starting the second control.

4. A vehicle-to-vehicle distance control device as described in claim 1, wherein the driving force control unit reduces the driving force so that the speed of the host vehicle becomes the second speed when the speed of the preceding vehicle decreases from a first speed to a second speed lower than the first speed after starting the second control.

5. A vehicle distance control device as described in claim 1, wherein, when the speed of the preceding vehicle is not identified in the second control, the driving force control unit regulates the driving force of the subject vehicle by regulating the driving force requested by the driver of the subject vehicle so that it does not exceed the driving force corresponding to the speed of the preceding vehicle identified immediately before that.

6. A vehicle-to-vehicle distance control device as described in claim 5, further comprising an operation amount detection unit that detects an amount of driving force operation by a driver of the vehicle, and the driving force control unit terminates the second control when the driving force corresponding to the driving force operation amount detected by the operation amount detection unit becomes smaller than the driving force corresponding to the speed of the preceding vehicle.

7. A vehicle-to-vehicle distance control device as described in claim 1, further comprising a notification control unit that executes notification control to notify the driver of the vehicle of information, wherein the notification control unit starts the notification control when the vehicle-to-vehicle distance becomes a fifth distance that is longer than the first distance and the fifth distance is equal to or less than a distance that has been preset as a distance at which the notification control is started.

8. The inter-vehicle distance control device according to claim 7, wherein the notification control unit notifies the driver of the information by varying the driving force during the notification control.

9. A vehicle-to-vehicle distance control device as described in claim 1, further comprising a driving lane discrimination unit that determines whether the host vehicle and the preceding vehicle are traveling in the same lane, and the driving force control unit executes the first control and the second control when the driving lane discrimination unit determines that the host vehicle and the preceding vehicle are traveling in the same lane.

10. A vehicle-to-vehicle distance control device as described in claim 1, further comprising a sign detection unit that detects road signs present ahead of the vehicle, and the driving force control unit executes the second control to restrict the driving force of the vehicle so that it does not exceed the driving force corresponding to the lower of the speed limit indicated by the road sign detected by the sign detection unit and the speed of the preceding vehicle identified by the speed identification unit.

11. The inter-vehicle distance control device according to claim 1, wherein the driving force control unit controls the driving force of the host vehicle by adjusting a throttle opening of the host vehicle.

12. A vehicle-to-vehicle distance control method comprising: a distance specifying step for specifying the inter-vehicle distance between a vehicle and a preceding vehicle traveling ahead of the vehicle; a speed specifying step for specifying the speed of the preceding vehicle; and a driving force control step for controlling the driving force of the vehicle, wherein in the driving force control step, when the inter-vehicle distance specified in the distance specifying step changes from a first distance to a second distance shorter than the first distance and the second distance is equal to or shorter than a first control execution start distance previously set as a distance for starting the first control, a first control is initiated to reduce the driving force of the vehicle; and further, in the driving force control unit step, when the inter-vehicle distance that has become the second distance becomes a third distance shorter than the second distance and the third distance is a second control execution start distance previously set as a distance for starting the second control, a second control is initiated to restrict the driving force of the vehicle so that it does not exceed the driving force of the vehicle corresponding to the speed of the preceding vehicle specified in the speed specifying step.

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