VEHICLE-VEHICLE CONTROL DEVICE AND VEHICLE-VEHICLE CONTROL PROCEDURES

Abstract

Vehicle-to-vehicle control device (40) attached to a vehicle (3) and comprising: - a control device (403, 407, 409) that performs acceleration control of the own vehicle (3) on the basis of a physical actual-vehicle-vehicle size and a physical target-vehicle-vehicle size, wherein the physical actual-vehicle-vehicle size describes a detection value of a physical quantity corresponding to a vehicle-vehicle distance between the own vehicle and a preceding vehicle (5) and the physical target-vehicle-vehicle size describes a target value of the physical actual-vehicle-vehicle size; - a limiting device (405, S140 to S160) that sets a limit value for a desired jerk during acceleration control; - a detection device (405, S110, S120) that detects the occurrence of at least one of the following two events: (i) a first event in which the vehicle-to-vehicle distance decreases discontinuously; and (ii) a second event in which a target vehicle-to-vehicle distance increases discontinuously in accordance with the physical target vehicle-to-vehicle size; and - a determining device (405, S130) that determines a risk of collision with the vehicle ahead, as perceived by the driver of the own vehicle, based on an operating condition of the vehicle ahead with respect to the own vehicle, wherein - the limiting device then, when the detection device detects the first event and / or the second event, sets the limit value for the target jerk to a value based on the collision risk determined by the determining device, such that a change in deceleration of the own vehicle is kept lower when the determined collision risk decreases.

Description

BACKGROUND OF THE INVENTION (Field of Invention)

[0001] The present invention relates to a vehicle-to-vehicle control device and a vehicle-to-vehicle control method. (Related technology)

[0002] From JP 2000 - 108 720 A, a vehicle-to-vehicle control device is known that controls the vehicle-to-vehicle distance between a vehicle and a vehicle ahead. The vehicle-to-vehicle control device detects, for example, the vehicle-to-vehicle distance between a vehicle and a vehicle ahead using a radar device. Based on the detected vehicle-to-vehicle distance, the vehicle-to-vehicle control device then performs acceleration control of the vehicle such that the vehicle-to-vehicle distance approaches a target vehicle-to-vehicle distance.According to another example, the vehicle-to-vehicle control device controls the vehicle-to-vehicle distance by performing acceleration control of the vehicle in such a way that a vehicle-to-vehicle time, obtained by dividing the detected vehicle-to-vehicle distance by the speed of the own vehicle, approximates a target vehicle-to-vehicle time.

[0003] In the related technique described above, the driver may perform an overtaking maneuver to get closer to the vehicle in front. A physical actual vehicle-to-vehicle size corresponding to the recorded vehicle-to-vehicle distance or the recorded vehicle-to-vehicle time may fall below a physical target vehicle-to-vehicle size corresponding to the target vehicle-to-vehicle distance or the target vehicle-to-vehicle time.

[0004] In this case, the target physical vehicle-vehicle size is modified to approximate the actual physical vehicle-vehicle size and then gradually increased over time to control the vehicle's deceleration. The target physical vehicle-vehicle size is modified to approximate the actual physical vehicle-vehicle size that should be realized when the relative speed between the vehicle and the vehicle ahead decreases. The target physical vehicle-vehicle size is modified to approximate the actual physical vehicle-vehicle size when the relative speed between the vehicle and the vehicle ahead increases.

[0005] In the related technique, as described above, the degree of deceleration is suppressed, and subsequently the driving feel is improved. The following are examples of situations in which the actual physical vehicle-to-vehicle size falls below the target physical vehicle-to-vehicle size. For example, a new vehicle ahead cuts in front of the vehicle in front. Alternatively, the target physical vehicle-to-vehicle size is changed to a high value as a result of a change in operating mode.

[0006] In the related technique described above, the degree of deceleration is suppressed by changing the physical target vehicle-to-vehicle size. For example, if a new vehicle ahead cuts in front of the vehicle in front, and the vehicle-to-vehicle distance changes discontinuously, an unnecessarily high degree of deceleration can occur. The following can be shown as an example of a case where an unnecessarily high degree of deceleration occurs: For instance, an excessively high degree of deceleration, disproportionate to the collision risk with the vehicle ahead as perceived by the driver, may occur, thus causing the driver discomfort. Consequently, the related technique described above still offers room for improvement with regard to the driving experience.

[0007] From DE 102 51 037 A1, a device for adaptive distance and speed control in motor vehicles is also known, comprising a sensor device for measuring the distance and relative speed of a target object located in front of the vehicle, a control device that has a distance control function for regulating to a specific distance to the target object and outputs time-varying control variables to actuators of the drive and / or brake system of the vehicle, a jerk limiter for limiting the temporal changes of the control variables, and a dynamic device that detects sudden changes in the traffic situation detected by the sensor device and, depending on the situation, restricts the function of the jerk limiter while distance and speed control continues.

[0008] DE 603 ​​04 628 T2 teaches an accelerator pedal device that applies reaction force to an accelerator pedal, and DE 60 2004 001 922 T2 relates to a method and a device for evaluating the front / rear collision risk between vehicles. SUMMARY

[0009] The purpose of the present disclosure is to provide a vehicle-to-vehicle control device and a vehicle-to-vehicle control method that can achieve a deceleration behavior of a vehicle that is suitable for a driver's perception.

[0010] The problem is solved by a vehicle-to-vehicle control device according to claim 1 and a vehicle-to-vehicle control method according to claim 9. Advantageous embodiments are the subject of the dependent claims.

[0011] An exemplary embodiment of the present invention provides a vehicle-to-vehicle control device that is attached to a vehicle and comprises a control unit, a limiting unit, a detection unit and a determination unit.

[0012] The control unit performs acceleration control of a vehicle based on a physical actual-vehicle distance and a physical target-vehicle distance. The physical target-vehicle distance describes a setpoint for the physical actual-vehicle distance. The physical actual-vehicle distance describes a measured value of a physical quantity corresponding to the vehicle-to-vehicle distance between the vehicle and a vehicle ahead.

[0013] The limiting device determines a limit value for a target jerk during acceleration control. The detection device detects the occurrence of at least one of the following two events: (i) an event (first event) in which the vehicle-to-vehicle distance decreases discontinuously; and (ii) an event (second event) in which a target vehicle-to-vehicle distance increases discontinuously according to the physical target vehicle-to-vehicle size. An example of the first event could be an event in which a new vehicle ahead merges in front of the vehicle being driven. An example of the second event could be an event in which the target vehicle-to-vehicle distance changes to a value greater than the actual value as a result of a change in the vehicle's operating mode.

[0014] The device determines the perceived risk of a collision with the vehicle ahead, as perceived by the driver of the vehicle. The device determines this risk based, for example, on the operating condition of the vehicle ahead relative to the vehicle. Furthermore, the device can be designed to determine the collision risk based on the relative speed between the vehicle ahead and the vehicle.

[0015] When the detection device registers the events described above, the limiting device sets the target jerk limit to a value based on the collision risk determined by the determining device. This ensures that the change in the vehicle's deceleration can be kept smaller when the determined collision risk decreases.

[0016] In the vehicle-to-vehicle control device of the exemplary embodiment, the target jerk, as described above, is provided with a limit value. Consequently, even if a new vehicle ahead merges in front of the vehicle in question and the actual vehicle-to-vehicle size changes discontinuously, a sudden deceleration caused by a discrepancy between the actual vehicle-to-vehicle size and the target vehicle-to-vehicle size can be suppressed.

[0017] Furthermore, in the vehicle-to-vehicle control system, the change in deceleration is kept smaller as the collision risk decreases, based on the vehicle's perceived risk of collision with the vehicle ahead. If the driver perceives a high risk of collision, the necessary immediate deceleration of the vehicle is generated. If the driver does not perceive a high risk of collision, the unpleasant feeling of sudden deceleration is suppressed. Consequently, the vehicle-to-vehicle control system can implement a desirable vehicle deceleration behavior that is appropriate for the driver's perception.

[0018] When the first event and / or the second event is detected, the limiting device, as the limit of the target jerk, can adjust the upper limit of a target deceleration gradient such that: (i) the upper limit gradually increases over time from an initial value; and (ii) the slope of the upper limit is kept lower when the collision risk determined by the determining device decreases.

[0019] By configuring the vehicle-to-vehicle control device in this way, a sudden deceleration caused by the occurrence of the events described above can be suppressed at an early stage. Furthermore, the actual physical vehicle-to-vehicle size can be changed to the desired physical vehicle-to-vehicle size at a given speed, based on the driver's perceived risk of collision.

[0020] Furthermore, when the first event and / or the second event is detected, the limiting device can adjust the upper limit such that: (i) the upper limit gradually increases from an initial value to a standard value over time; and (ii) the time it takes for the upper limit of the deceleration gradient to change from the initial value to the standard value increases as the collision risk decreases. The above-described technique for changing the target jerk limit allows the limit to be appropriately adjusted through a simple process. This enables the implementation of a deceleration behavior that is desirable from the driver's perspective. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The attached drawings show: Fig. 1 a block diagram of a configuration of an on-board system according to an embodiment; Fig. 2. A block diagram of functions that are called from the onboard system by a control device. Fig. 1 be realized; Fig. 3. A flowchart of a process that is modified by a correction unit in the functions of the control device from the Fig. 2 is realized; Fig. 4. An illustration to demonstrate the relationship between an actual vehicle-to-vehicle distance and a target vehicle-to-vehicle distance before and after a change in the target vehicle-to-vehicle distance; Fig. 5. An illustration to demonstrate a correspondence between a driving condition of a vehicle ahead and a collision risk; Fig. 6. A diagram of limit values ​​for a target jerk and a curve for a target acceleration; and Fig. 7 a diagram of the correspondence between a collision risk and a relaxation time. DESCRIPTION OF THE EXECUTION FORMS

[0022] An example of the present invention is described below with reference to the drawings.

[0023] Fig. Figure 1 shows an onboard system 1 of the present example. The onboard system 1 is attached to a vehicle, such as a two-wheeler or a four-wheeled vehicle. The onboard system 1 is designed to control the vehicle-to-vehicle distance between a vehicle 3 and a preceding vehicle 5 by controlling the internal combustion engine and the brakes. The onboard system 1 essentially comprises an object detection device 10, a vehicle speed sensor 20, an input interface 30, a control device 40, an electronic internal combustion engine control unit (ECU) 50, and a brake ECU 60. The devices forming the onboard system 1 are interconnected via a vehicle network. Alternatively, the devices are directly connected to the control device 40 via specific cables.

[0024] The object detection device 10 functions as a radar device. The object detection device 10 transmits detection waves (such as optical or electromagnetic waves) into an area in front of the vehicle 3 and then receives reflected waves of the detection waves to detect an object located ahead. The object detection device 10 detects the distance between the vehicle 3 and the object located ahead, the orientation of the object located ahead relative to the vehicle 3, and the relative speed of the object located ahead relative to the vehicle 3.

[0025] The object detection device 10 can be configured to also include a camera that captures images of the area in front of the vehicle 3. In this case, the object detection device 10 can be designed to detect an object located ahead based on the images captured by the camera. The object detection device 10 can then determine the object type. The object detection device 10 can also determine the object's position relative to the vehicle 3's lane.

[0026] The object detection device 10 detects the vehicle 5 ahead based on the detection results described above. The vehicle 5 ahead is a vehicle traveling in front of the vehicle 3 in the same lane as the vehicle 3. The object detection device 10 identifies a distance (more precisely, the vehicle-to-vehicle distance) D and a relative speed W of the vehicle 5 ahead with respect to the vehicle 3. The object detection device 10 transmits the information about the vehicle-to-vehicle distance D and the relative speed W to the control device 40.

[0027] Meanwhile, the vehicle speed sensor 20 detects the vehicle speed V of the vehicle 3. The vehicle speed sensor 20 then transmits the speed information to the control device 40. Furthermore, the input interface 30 transmits operating information about actions performed by the driver to the control device 40. The input interface 30 includes, as switches that can be operated by the driver, a switch for entering an execution command for a vehicle-to-vehicle control process and a switch for changing operating modes.

[0028] The control device 40 starts the vehicle-to-vehicle control process when the execution command is entered via the input interface 30. In the vehicle-to-vehicle control process, the control device 40 controls the vehicle-to-vehicle distance D based on the information about the vehicle-to-vehicle distance D and the relative speed W, which are entered by the object detection device 10, and the vehicle speed V of the own vehicle 3, which is entered by the vehicle speed sensor 20, to a target vehicle-to-vehicle distance Dr.

[0029] The control device 40 comprises a CPU 41, a ROM 43, and a RAM 45. The ROM 43 stores various programs. The RAM 45 is used as a workspace when the CPU 41 executes processes. The control device 40 performs various functions required for vehicle-to-vehicle control through the CPU 41, which executes various processes based on the programs described above. When the vehicle-to-vehicle control process occurs, the control device 40 sends a drive command or a brake command to the internal combustion engine ECU 50 or the brake ECU 60 to control the acceleration A of the vehicle.

[0030] In the present application, the "acceleration" in the direction in which the vehicle 3 accelerates ahead is set to a positive value. Conversely, the "acceleration" in the direction of deceleration is set to a negative value. "Deceleration" in the present application refers to a value obtained by inverting the sign (positive / negative) of the "acceleration." The "relative speed" of the vehicle 5 ahead with respect to the vehicle 3 is set to a positive value if the speed of the vehicle 5 ahead is greater than the speed of the vehicle 3. The "relative speed" is set to a negative value if the speed of the vehicle 5 ahead is less than the speed of the vehicle 3.

[0031] The combustion engine ECU 50 controls the combustion engine such that the wheels generate a drive torque based on the drive command from the control device 40 described above. The brake ECU 60 controls the hydraulic brake such that the wheels generate a braking torque based on the braking command from the control device 40.

[0032] The following describes in more detail a configuration of the control device 40. Since the CPU 41 executes various processes based on the programs, the control device 40 serves, as shown in Fig. 2 shown as a setpoint vehicle-to-vehicle distance adjustment unit 401, a setpoint jerk adjustment unit 403, a correction unit 405, a setpoint acceleration adjustment unit 407, and an acceleration control unit 409. However, the control device 40 can be configured as a specific circuit comprising a circuit group that serves as these units.

[0033] The target vehicle-to-vehicle distance setting unit 401 sets the target vehicle-to-vehicle distance Dr between the vehicle 3 and the vehicle 5 ahead. Specifically, the target vehicle-to-vehicle distance setting unit 401 sets the target vehicle-to-vehicle distance Dr according to the operating mode selected by the driver, based on a command entered by the driver via the input interface 30. The operating modes include a short-distance mode and a long-distance mode.

[0034] When the short-distance mode is selected as the operating mode, the target vehicle-to-vehicle distance setting unit 401 sets a target vehicle-to-vehicle distance Dr1 for short-distance mode. The target vehicle-to-vehicle distance Dr1 for short-distance mode is predetermined. Conversely, when the long-distance mode is selected as the operating mode, the target vehicle-to-vehicle distance setting unit 401 sets a target vehicle-to-vehicle distance Dr2 for long-distance mode. The target vehicle-to-vehicle distance Dr2 for long-distance mode is greater than the target vehicle-to-vehicle distance Dr1 for short-distance mode.

[0035] The target jerk adjustment unit 403 sets a target jerk Jr to approximate the vehicle-to-vehicle distance D to the target vehicle-to-vehicle distance Dr, based on the vehicle-to-vehicle distance D detected by the object detection device 10 and the target vehicle-to-vehicle distance Dr. In addition to the vehicle-to-vehicle distance D and the target vehicle-to-vehicle distance Dr, the target jerk Jr can be set using the velocity V and the acceleration A of the vehicle 3.

[0036] In the present application, the actual vehicle-to-vehicle distance, jerk, acceleration, and speed are indicated rather than the target values ​​when simply referring to the vehicle-to-vehicle distance, jerk, acceleration, and speed. The acceleration A of the vehicle 3 can be determined by a time derivative of the speed V detected by the vehicle speed sensor 20. The jerk Jr can be determined by a time derivative of the acceleration A.

[0037] The following procedure is already known. In this known procedure, the target acceleration Ar or the target jerk Jr is set to approximate the vehicle-to-vehicle distance D to the target vehicle-to-vehicle distance Dr. The vehicle-to-vehicle distance D is controlled to the target vehicle-to-vehicle distance Dr based on the target acceleration Ar or the target jerk Jr. The target jerk setting unit 403 can set the target jerk Jr based on this known procedure.

[0038] The correction unit 405 corrects the target jerk Jr. set by the target jerk setting unit 403. The correction unit 405 then sends the corrected target jerk Jc to the target acceleration setting unit 407. Specifically, the correction unit 405 corrects when the target jerk Jr. input by the target jerk setting unit 403 is below a target jerk limit value (hereinafter simply referred to as a "limit") JL, which is set to a negative value (Jr). <JL), den Soll-Ruck Jr auf den Grenzwert JL. Anschließend gibt die Korrektureinheit 405 den korrigierten Soll-Ruck Jc=JL an die Soll-Beschleunigungs-Einstelleinheit 407.

[0039] In contrast, the correction unit 405 does not correct the target jerk Jr if the target jerk Jr input by the target jerk setting unit 403 is greater than or equal to the limit JL (Jr > JL). The correction unit 405 sets the corrected target jerk Jc to the same value as the target jerk Jr. The correction unit 405 then outputs the corrected target jerk Jc = Jr to the target acceleration setting unit 407. The sign-inverted value (-JL) of the limit JL corresponds to an upper limit of a target deceleration gradient (the time derivative of a target deceleration).

[0040] In the onboard system 1 of the present example, if the target jerk Jc has a negative value, the deceleration of the own vehicle 3 is increased more quickly when the target jerk Jc decreases (when the absolute value increases).

[0041] The target acceleration setting unit 407 sets the target acceleration Ar according to the target jerk Jc based on the corrected target jerk Jc, which is corrected by the correction unit 405. The acceleration control unit 409 calculates the required drive torque or brake torque to approximate the acceleration A of the vehicle 3 to the target acceleration Ar, based on the acceleration A of the vehicle 3 and the target acceleration Ar set by the target acceleration setting unit 407. The acceleration control unit 409 then issues a drive command or a brake command to the internal combustion engine ECU 50 or the brake ECU 60 to apply the drive torque or brake torque. This causes the acceleration control unit 409 to control the acceleration A of the vehicle 3 to the target acceleration Ar.

[0042] If the one in the Fig. When the process shown in section 3 is started, the correction unit 405 determines whether or not a lane-closing event has occurred due to a preceding vehicle 5 (step S110). The lane-closing event due to a preceding vehicle 5 refers to an event in which a new preceding vehicle 5 enters the area in front of the vehicle 3.

[0043] When it is determined that a lane-cutting event has occurred due to a preceding vehicle 5, the reference point for the vehicle-to-vehicle distance D changes from the existing preceding vehicle 5 to the new preceding vehicle 5 that has cut in between the own vehicle 3 and the existing preceding vehicle 5. The vehicle-to-vehicle distance D between the own vehicle 3 and the preceding vehicle 5 becomes discontinuously shorter. This results in a discrepancy between the vehicle-to-vehicle distance D and the target vehicle-to-vehicle distance Dr. The target jerk adjustment unit 403 sets a target jerk Jr with a high target deceleration gradient to reduce the discrepancy.

[0044] More precisely, the target jerk adjustment unit 403 sets the target jerk Jr to a negative value with a high absolute value. In the present example, the target jerk Jr is corrected in such a situation by a specific procedure. Consequently, the determination described above takes place. The determination as to whether or not the lane-cutting event has occurred can be realized by the object detection device 10, which provides the control device 40 with the information about the preceding vehicle 5 that is necessary for the determination.

[0045] If it is determined that the rejoining event occurred (YES in step S110), correction unit 405 advances to step S130. If it is determined that the rejoining event did not occur (NO in step S110), correction unit 405 advances to step S120.

[0046] After advancing to step S120, the correction unit 405 determines whether or not a switching event has occurred. The switching event refers to the case where the operating mode for the vehicle-to-vehicle control changes from the short-distance mode described above to the long-distance mode. This determination can be achieved by monitoring the operating information via the input interface 30.

[0047] As a result of the switching event, the target vehicle-to-vehicle distance Dr, as in Fig. Figure 4 shows the system switching discontinuously from the target vehicle-to-vehicle distance Dr=Dr1 in short-distance mode to the target vehicle-to-vehicle distance Dr=Dr2 in long-distance mode. A discrepancy occurs between the vehicle-to-vehicle distance D and the target vehicle-to-vehicle distance Dr. This causes the target jerk adjustment unit 403 to adjust the target jerk Jr, which has a high target deceleration gradient, to reduce the discrepancy, in a manner similar to the case where the merging event occurs due to the preceding vehicle 5.

[0048] Accordingly, if it is determined that the switching event described above has occurred (YES in step S120), the correction unit 405 advances to step S130. Conversely, if it is determined that the switching event has not occurred (NO in step S120), the correction unit 405 advances to step S180.

[0049] After advancing to step S180, the correction unit 405 sets the limit JL of the target jerk Jr to a default value JL0. The default value JL0 is a negative value that is predetermined by the developer. Subsequently, based on the limit JL=JL0, the correction unit 405 outputs the corrected target jerk Jc, corresponding to the target jerk Jr, to the target acceleration adjustment unit 407 (step S190).

[0050] More precisely, if it is determined that the target jerk Jr is below the limit JL=JL0, the correction unit 405 corrects the target jerk Jr to the limit JL=JL0. The correction unit 405 then sends the corrected target jerk Jc=JL0 to the target acceleration adjustment unit 407. Conversely, if it is determined that the target jerk Jr is greater than or equal to the limit JL=JL0, the correction unit 405 sets the corrected target jerk Jc to the same value as the target jerk Jr. The correction unit 405 then sends the corrected target jerk Jc=Jr to the target acceleration adjustment unit 407. Following this, the correction unit 405 terminates the process described in the... Fig. The process shown in point 3 is temporary.

[0051] Conversely, after advancing to step S130, correction unit 405 calculates a collision risk Z. The collision risk Z refers to the risk of a collision between the vehicle 3 and the vehicle 5 ahead, as perceived by the driver of the vehicle 3. Specifically, the collision risk Z is calculated based on the vehicle-to-vehicle distance D between the vehicle 3 and the vehicle 5 ahead, the relative speed W of the vehicle 5 ahead with respect to the vehicle 3, and the speed V of the vehicle 3. The collision risk Z is calculated, for example, based on the following equation. Z=α / THW+β / TTC THW=D / V TTC=D / (−W)

[0052] Here, α and β represent positive coefficients. In the equation described above, the collision risk Z is calculated such that it is higher when the speed V of the vehicle 3 with respect to the vehicle-to-vehicle distance D increases. Furthermore, the collision risk Z is calculated such that it is higher when the relative speed W with respect to the vehicle-to-vehicle distance D in the direction (negative direction) in which the preceding vehicle 5 is approaching the vehicle 3 assumes a higher value. The relative speed W with respect to the vehicle-to-vehicle distance D represents the operating state of the preceding vehicle 5. However, the lower limit of the collision risk Z is zero.

[0053] The driver tends to perceive a higher risk of collision with the vehicle 5 ahead when the speed V of vehicle 3 increases with respect to the vehicle-to-vehicle distance D. Furthermore, the driver tends to perceive a higher risk of collision with the vehicle 5 ahead when the time until collision TTC with the vehicle 5 ahead decreases. Consequently, since a result of the risk of collision Z is calculated based on the equation above, a suitable value can be calculated as the collision risk perceived by the driver.

[0054] The section on the left side in the Fig. Figure 5 shows an example where the vehicle-to-vehicle distance D is shorter than the target vehicle-to-vehicle distance Dr as a result of the merging event by the vehicle 5 in front. In this example, the speed of the vehicle 5 in front is 80 km / h. The speed of the vehicle in question is 60 km / h. The section on the right in the Fig. Figure 5 shows an example where the speed of the vehicle in front is 60 km / h. The speed of the vehicle in question is 60 km / h.

[0055] If the combination of the vehicle-to-vehicle distance D and the target vehicle-to-vehicle distance Dr is both in the first example in the section on the left in the Fig. 5 as well as in the second example in the section on the right-hand side in the Fig. Since 5 is equal, the collision risk Z=Z1 in the first example is calculated in such a way that it has a lower value than the collision risk Z=Z2 in the second example.

[0056] In the first example, the relative speed W is positive, and the vehicle 5 ahead is moving away from the vehicle 3. In the second example, the relative speed W is zero. Furthermore, the collision risk Z=Z1 in the first example and the collision risk Z=Z2 in the second example are calculated such that they have values ​​lower than the collision risk Z for the case where the relative speed W is negative and the vehicle 3 is approaching the vehicle 5 ahead.

[0057] After the collision risk calculation Z is completed, such as the one described above, the correction unit 405 sets a reduction time Tx based on the calculated collision risk (step S140). The reduction time Tx refers to the time it takes for the limit JL to be reduced to the default value JL0.

[0058] In the present example, as in the section above, the Fig. Figure 6 shows that when the lane-cutting event caused by the preceding vehicle 5 and the operating mode changeover event occur, the limit value JL gradually changes from its initial value of zero to the standard value JL0 in a linear fashion. More precisely, the upper limit (-JL) of the target deceleration gradient (-Jr) is gradually changed to increase from its initial value of zero to the standard value (-JL0). The decrease time Tx corresponds to the time interval that elapses until the limit value JL has changed from its initial value of zero to the standard value JL0 in this manner.

[0059] The dotted line in the diagram, which shows time t with respect to the limit JL, specifically in the upper section of the Fig. Figure 6 describes the limiting curve JL when the decay time Tx has a value Tx1. The dashed line describes the limiting curve JL when the decay time Tx has a value Tx2 that is greater than the value Tx1. The solid line describes the limiting curve JL when the decay time Tx has a value Tx3 that is greater than the value Tx2.

[0060] Meanwhile, the dotted line in the diagram showing time t with respect to the target acceleration Ar is located in the lower section of the Fig. Figure 6 shows an example of the target acceleration Ar when the deceleration time Tx has the value Tx1. The dashed line is an example of the target acceleration Ar when the deceleration time Tx has the value Tx2. The solid line is an example of the target acceleration Ar when the deceleration time Tx has the value Tx3.

[0061] The reduction time Tx is, as in Fig. Figure 7 shows the function being set to be either a monotonically non-increasing or a monotonically decreasing function with respect to the collision risk Z. In this ratio, the reduction time Tx is set to a higher value as the collision risk Z decreases. The function shown in the Fig. The correlation shown in Figure 7 between the collision risk Z and the reduction time Tx serves only as an example. Various ratios can be used where the reduction time Tx increases as the collision risk Z decreases.

[0062] In the present example, the reduction time Tx is set to a higher value when the collision risk Z decreases. Consequently, the slope of the limit JL (i.e., the upper limit of the target deceleration gradient) is kept lower when the collision risk Z decreases. The target acceleration (target deceleration) is changed gradually. This allows the jerk J (deceleration gradient) in the vehicle 3 to be suppressed immediately after the occurrence of the events described above. An unnecessary sudden deceleration of the vehicle 3 can be avoided, as described in the section below. Fig. 6 shown, can be prevented. The driving experience can be improved.

[0063] In step S140, the reduction time Tx is set based on the collision risk Z calculated in step S130, using a function that shows the correspondence between the collision risk Z and the reduction time Tx, which has been determined in advance. Alternatively, in step S140, the reduction time Tx can be set based on the collision risk Z calculated in step S130 using a table that shows the correspondence between the collision risk Z and the reduction time Tx, which has been stored in advance in ROM 43. The function and the table can be generated based on the results of experiments regarding driving feel.

[0064] The control device 40 then advances to step S150. The control device 40 determines whether or not the elapsed time t since the occurrence of the shearing-in or switching event described above has exceeded the reduction time Tx. If it is determined that the elapsed time t has not exceeded the reduction time Tx (NO in step S150), the control device 40 advances to step S160. This causes the control device 40 to repeatedly execute the processes in steps S160 and S170 until the elapsed time t exceeds the reduction time Tx.

[0065] In step S160, the control device 40 calculates and determines the limit value JL using the following equation based on the default value JL0, the elapsed time t and the reduction time Tx. JL=(JL0 / Tx)⋅t

[0066] In step S170, the correction unit 405 then makes a correction if it is determined that the target jerk Jr is below the limit value JL (Jr <JL), den Soll-Ruck Jr auf den Grenzwert JL. Anschließend gibt die Korrektureinheit 405 den korrigierten Soll-Ruck Jc=JL=(JL0 / Tx)·t an die Soll-Beschleunigungs-Einstelleinheit 407. Wenn bestimmt wird, dass der Soll-Ruck Jr größer oder gleich dem Grenzwert JL ist (Jr≥JL), setzt die Korrektureinheit 405 den korrigierten Soll-Ruck Jc auf den gleichen Wert wie der Soll-Ruck Jr. Anschließend gibt die Korrektureinheit 405 den korrigierten Soll-Ruck Jc=Jr an die Soll-Beschleunigungs-Einstelleinheit 407.

[0067] In this way, the correction unit 405 adjusts the limit JL when the events described above occur, so that it gradually changes from the initial value of zero to the standard value JL0 over time. This suppresses sudden delays. More precisely, the correction unit 405 adjusts the upper limit (=JI) of the target delay gradient so that it gradually changes from the initial value of zero to the standard value (-JL). The correction unit 405 thus corrects the target jerk Jr to suppress sudden delays.

[0068] Subsequently, the correction unit 405 sets the limit JL to the default value JL0 (step S180) when it is determined that the elapsed time t has exceeded the reduction time Tx (JA in step S150). The correction unit 405 then corrects the target jerk Jr based on the default value JL0 (step S190).

[0069] The onboard system 1 of the present example is described above. In onboard system 1, when the events described above occur, the limit JL is set for the target jerk Jr based on the driver's perceived collision risk Z with the vehicle 5 ahead. By setting the limit JL, the jerk in the vehicle 3 can be limited, regardless of the discrepancy between the vehicle-to-vehicle distance D and the target vehicle-to-vehicle distance Dr. The occurrence of a sudden deceleration caused by the discrepancy, which is disproportionate to the risk perceived by the driver, can be prevented in the vehicle 3.

[0070] In particular, in the onboard system 1, based on the driver's perceived collision risk Z with the vehicle 5 ahead, the change in deceleration is kept lower when the collision risk Z decreases. Consequently, when the driver perceives a high collision risk, the necessary sudden deceleration of the vehicle 3 is generated. If the driver does not perceive a high collision risk, a negative driving experience due to sudden deceleration is suppressed. Accordingly, in the onboard system 1, a desirable vehicle deceleration behavior, suitable for the driver's perception, can be achieved.

[0071] Furthermore, in the onboard system 1, the collision risk Z is calculated based on the relative speed W between the vehicle 5 ahead and the vehicle 3. Consequently, the collision risk Z perceived by the driver can be calculated appropriately. In particular, in the onboard system 1, based on the actual vehicle-to-vehicle distance D, the speed V of the vehicle 3, and the relative speed W, the collision risk Z is calculated such that it is higher when the speed V of the vehicle 3 increases with respect to the vehicle-to-vehicle distance D, and when the relative speed W with respect to the vehicle-to-vehicle distance D increases in the direction in which the vehicle 5 ahead is approaching the vehicle 3. Consequently, a more suitable value than the collision risk Z can be calculated.

[0072] Furthermore, in the onboard system 1, if the events described above do not occur, the limit JL is set to the default value JL0. If the events are detected, the limit JL is adjusted such that the upper limit (the sign-inverted value of limit JL) of the target delay gradient is set to gradually increase from the initial value of zero to the default value over time. Additionally, the limit JL is adjusted such that the slope of the upper limit is kept smaller as the collision risk Z decreases.

[0073] Consequently, a sudden deceleration due to the occurrence of the events described above can be suppressed at an early stage. Furthermore, the vehicle-to-vehicle distance D can be changed to the target vehicle-to-vehicle distance Dr at a speed based on the collision risk Z perceived by the driver.

[0074] The present invention is not limited to the example described above, but can be implemented in various ways. Instead of the vehicle-to-vehicle distance D and the target vehicle-to-vehicle distance Dr, for example, the vehicle-to-vehicle time (D / V) and the target vehicle-to-vehicle time (Dr / V) can be used to execute the vehicle-to-vehicle control of the self-propelled vehicle 3. Here, the vehicle-to-vehicle time (D / V) and the target vehicle-to-vehicle time (Dr / V) are the vehicle-to-vehicle distance D and the target vehicle-to-vehicle distance Dr, respectively, divided by the speed V of the self-propelled vehicle 3.

[0075] Furthermore, in the example described above, the onboard system 1 is mounted in a vehicle that uses an internal combustion engine as a power source. However, the present invention can be mounted on / be mounted on various types of vehicles, such as a vehicle that uses an electric motor as a power source. Furthermore, the present invention can be applied to an onboard system that executes a deceleration control only when the vehicle-to-vehicle distance is below the target vehicle-to-vehicle distance, without executing the acceleration control when the vehicle-to-vehicle distance is above the target vehicle-to-vehicle distance.

[0076] Furthermore, the procedure for calculating the collision risk Z perceived by the driver is not limited to the equation described above. The collision risk Z can, for example, be calculated taking into account the road environment, the driver's personality, and similar factors, in addition to the operating state of the vehicle 5 ahead. For instance, uncertainties regarding the behavior of the vehicle 5 ahead a few seconds in the future are greater on a local road compared to a highway. It is taken into account that the driver is more likely to perceive danger. Consequently, an increase in the permissible target deceleration gradient can be considered. Furthermore, information regarding the driver's personality can be collected from the driver via the input interface 30. The calculation equation for the collision risk Z can then be modified.Alternatively, the reduction time Tx with respect to the collision risk Z can be changed.

[0077] Finally, the correspondence is described. The control device 40 is an example of the vehicle-to-vehicle control device. The set jerk adjustment unit 403, the set acceleration adjustment unit 407, and the acceleration control unit 409 are examples of the control device (equivalent to a control unit or controller). The functions implemented by steps S110 and S120, which are performed by the correction unit 405, correspond to functions implemented by the sensing device (equivalent to a sensing unit or detector). The functions implemented by step S130 correspond to functions implemented by the determining device (equivalent to a determining unit or determiner).The functions implemented by steps S140 to S160 are an example of functions implemented by the limiting device (equivalent to a limiting unit or limiter).

Claims

[1] Vehicle-to-vehicle control device (40) attached to a vehicle (3) and comprising: - a control device (403, 407, 409) that performs acceleration control of the own vehicle (3) on the basis of a physical actual-vehicle-vehicle size and a physical target-vehicle-vehicle size, wherein the physical actual-vehicle-vehicle size describes a detection value of a physical quantity corresponding to a vehicle-vehicle distance between the own vehicle and a preceding vehicle (5) and the physical target-vehicle-vehicle size describes a target value of the physical actual-vehicle-vehicle size; - a limiting device (405, S140 to S160) that sets a limit value for a desired jerk during acceleration control; - a detection device (405, S110, S120) that detects the occurrence of at least one of the following two events: (i) a first event in which the vehicle-to-vehicle distance decreases discontinuously; and (ii) a second event in which a target vehicle-to-vehicle distance increases discontinuously in accordance with the physical target vehicle-to-vehicle size; and - a determining device (405, S130) that determines a risk of collision with the vehicle ahead, as perceived by the driver of the own vehicle, based on an operating condition of the vehicle ahead with respect to the own vehicle, wherein - the limiting device then, when the detection device detects the first event and / or the second event, sets the limit value for the target jerk to a value based on the collision risk determined by the determining device, such that a change in deceleration of the own vehicle is kept lower when the determined collision risk decreases. [2] Vehicle-to-vehicle control device according to claim 1, wherein the determining device determines the collision risk on the basis of a relative speed between the vehicle ahead and the vehicle being driven. [3] Vehicle-to-vehicle control device according to claim 1 or 2, wherein the limiting device, when the first event and / or the second event is detected, sets an upper limit of a target deceleration gradient such that: (i) the upper limit gradually increases from an initial value over time; and (ii) the slope of the upper limit is kept lower when the collision risk determined by the determining device decreases. [4] Vehicle-to-vehicle control device according to claim 3, wherein the limiting device, when the first event and / or the second event is detected, adjusts the upper limit such that: (i) the upper limit gradually increases from an initial value over time to a standard value; and (ii) the time interval until the upper limit of the deceleration gradient changes from the initial value to the standard value increases as the collision risk decreases. [5] Vehicle-to-vehicle control device according to any one of claims 1 to 4, wherein the determining device determines the collision risk on the basis of: (i) a vehicle-to-vehicle distance between the own vehicle and the vehicle ahead; (ii) a speed of the own vehicle; and (iii) a relative speed between the vehicle ahead and the own vehicle. [6] Vehicle-to-vehicle control device according to claim 5, wherein the determining device calculates the collision risk such that it has a higher value when the speed of the own vehicle with respect to the vehicle-to-vehicle distance increases, and when the relative speed with respect to the vehicle-to-vehicle distance in a direction in which the preceding vehicle is approaching the own vehicle assumes a higher value. [7] Vehicle-to-vehicle control device according to one of claims 1 to 6, wherein the detection device detects, as the occurrence of the first event in which the vehicle-to-vehicle distance decreases discontinuously, an occurrence of an event in which a new preceding vehicle merges into the area in front of the own vehicle. [8] Vehicle-to-vehicle control device according to one of claims 1 to 7, wherein the detection device detects, as the occurrence of the second event in which a target vehicle-to-vehicle distance increases discontinuously according to the physical target vehicle-to-vehicle size, an occurrence of an event in which the target vehicle-to-vehicle distance changes to a value which is above a current value as a result of a change in an operating mode of the vehicle. [9] Vehicle-to-vehicle tax procedure comprising the following steps: - Executing, by means of a control device (403, 407, 409) of a vehicle-to-vehicle control device (40) attached to a vehicle (3), an acceleration control of a self-propelled vehicle, which is the vehicle (3), based on a physical actual-vehicle-to-vehicle size and a physical target-vehicle-to-vehicle size, wherein the physical actual-vehicle-to-vehicle size describes a detection value of a physical quantity corresponding to a vehicle-to-vehicle distance between the self-propelled vehicle and a preceding vehicle (5) and the physical target-vehicle-to-vehicle size describes a target value of the physical actual-vehicle-to-vehicle size; - Setting, using a limiting device (405, S140 to S160) of the vehicle-to-vehicle control device, a limit value for a desired jerk during acceleration control; - Detect, using a detection device (405, S110, S120) of the vehicle-vehicle control device, the occurrence of at least one of the following two events: (i) a first event in which the vehicle-vehicle distance decreases discontinuously; and (ii) a second event in which a target vehicle-vehicle distance increases discontinuously in accordance with the physical target vehicle-vehicle size; - Determine, using a determining device (405, S130) of the vehicle-to-vehicle control device, a risk of collision with the vehicle ahead as perceived by the driver of the own vehicle, based on an operating state of the vehicle ahead with respect to the own vehicle; and - then, when the detection device detects the first event and / or the second event, adjust, using the limiting device, the limit of the target jerk to a value based on the specified collision risk, such that a change in deceleration of the own vehicle is kept lower when the specified collision risk decreases.

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