Driving control device

Abstract

To suppress acceleration and make a smooth turn in a state that ACC control is maintained, although a map locator is not loaded or in a situation when information according to a map locator cannot be acquired.SOLUTION: An ACC control unit 3 detects a self-vehicle speed Vs, and a steering angle absolute value |θst| when a handle is operated by a driver, and sets a steering angle correction value θs on the basis of the detected self-vehicle speed and a steering angular speed ωst set by time-differentiating the steering angle absolute value |θst|. Then, self-vehicle target acceleration αm during ACC control is set on the basis of a steering angle θst set by adding the steering angle correction value θs to the steering angle absolute value |θst| and the self-vehicle speed Vs. Since the steering angle θst is bulk-increased only by the steering angle correction value θs, as a result, the self-vehicle target acceleration αm is suppressed in accordance with handle operation of the driver.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cruise control device that can continue constant speed cruise control or follow-up cruise control even when the driver is turning the vehicle by operating the steering wheel. [Background technology]

[0002] In recent vehicles, various driving assistance technologies have been proposed to reduce the burden on the driver and enable comfortable and safe driving, and some of them have already been put into practical use. Adaptive Cruise Control (ACC) with automatic distance maintenance control is known as this type of driving assistance. In ACC control, for example, an on-board camera or various radar sensors mounted on the vehicle, or a driving environment recognition unit consisting of a combination of these, recognizes the distance to the preceding vehicle and makes the vehicle travel following the preceding vehicle, or, if there is no preceding vehicle ahead, makes the vehicle travel at a set vehicle speed set by the driver.

[0003] Furthermore, in vehicles equipped with a map locator function in addition to this ACC control function, it is possible to ascertain the current position of the vehicle from well-known GNSS (Global Navigation Satellite System) information and provide driving assistance (e.g., automatic driving) to guide the vehicle to a destination along a route set on a road map. In such driving assistance, road information such as road shape and curve curvature is obtained from map information, enabling the vehicle to turn at intersections and curves while maintaining ACC control.

[0004] However, not all commercially available vehicles are equipped with a map locator, etc. Also, some countries do not have a road information network required for providing driving assistance to the vehicle. Furthermore, while driving, the vehicle may travel in an environment where the reception sensitivity from GNSS satellites is low and the positioning signal cannot be effectively received, such as in a city surrounded by buildings or inside a tunnel. In such driving environments, ACC control is performed only based on information obtained from the driving environment recognition unit.

[0005] As described above, when a preceding vehicle to be followed is detected, the ACC control maintains a constant distance between the vehicles by accelerating and decelerating to follow the preceding vehicle. On the other hand, when a preceding vehicle to be followed is not detected, constant speed driving at a set vehicle speed is performed.

[0006] For example, Patent Document 1 (JP 2017-222317 A) discloses a technology that reduces the burden on the driver by continuing ACC control even when the vehicle follows a preceding vehicle into an intersection and then crosses an oncoming lane to turn toward an intersecting lane. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2017-222317 A Summary of the Invention [Problem to be solved by the invention]

[0008] In the technology disclosed in the above-mentioned document, when the vehicle is turned toward the intersecting lane crossing the oncoming lane and a preceding vehicle to be followed is not detected, normal ACC control is executed. Since the ACC control in this case is constant speed driving at a set vehicle speed, for example, after the vehicle enters an intersection in a predetermined deceleration state, when the driver operates the steering wheel in a direction crossing the oncoming lane, the ACC control tries to increase the speed of the vehicle (the vehicle speed) to the set vehicle speed with a preset target acceleration.

[0009] In this case, if the ACC control attempts to increase the vehicle speed at the same acceleration as when driving on a straight road, the vehicle will swerve outward, causing the driver to panic, as shown by the dashed line in Fig. 9. For this reason, a technique is known in which the ACC control reads the yaw rate detected by the yaw rate sensor when the driver is turning the steering wheel, and when this yaw rate exceeds a predetermined threshold, suppresses the acceleration by a target acceleration set according to this yaw rate.

[0010] However, with this technology, when the vehicle is turning, acceleration is not suppressed until a large yaw rate equal to or greater than a predetermined threshold is detected, which means that there is a high likelihood of a delay in the timing at which acceleration suppression begins, making it difficult to achieve a sufficient acceleration suppression effect.

[0011] In view of the above circumstances, the present invention aims to provide a driving control device that can perform smooth turning without delaying the timing of suppressing acceleration while maintaining ACC control, even in a situation where a map locator is not installed or information from the map locator cannot be obtained. [Means for solving the problem]

[0012] The present invention relates to a steering wheel operation by a driver. Self a steering angle detection unit that detects a steering angle absolute value, which is an absolute value of a rotation angle of a steering wheel of a vehicle based on a neutral position of the steering wheel; The aboveA driving control device having a vehicle speed detection unit that detects the speed of a host vehicle, and a cruise control unit that drives the host vehicle at a constant speed at a set vehicle speed or drives the host vehicle to follow a preceding vehicle, includes a steering angular velocity detection unit that calculates a steering angular velocity based on the steering angle absolute value detected by the steering angle detection unit, and the cruise control unit includes a steering angle correction value setting unit that sets a steering angle correction value that becomes larger as the steering angular velocity increases and that becomes larger as the speed of the host vehicle increases, and that is a positive value, based on the steering angular velocity detected by the steering angular velocity detection unit and the speed of the host vehicle detected by the vehicle speed detection unit, and a target acceleration setting unit that sets a target acceleration of cruise control that becomes smaller as the additional steering angle increases and that becomes smaller as the speed of the host vehicle increases, based on an added steering angle set by adding the steering angle correction value set by the steering angle correction value setting unit to the steering angle absolute value detected by the steering angle detection unit and the speed of the host vehicle detected by the vehicle speed detection unit. Effect of the Invention

[0013] According to the present invention, the steering angle is set by adding the steering angle correction value, which is set based on the speed and steering angle speed of the vehicle, to the absolute steering angle value, and the target acceleration of the cruise control is set based on this steering angle and the speed of the vehicle, so that the steering angle is set by increasing the steering angle by the steering angle correction value. As a result, the target acceleration is suppressed in response to the driver's steering wheel operation, and even in a situation where a map locator is not installed or information from the map locator cannot be obtained, it is possible to perform smooth turning while maintaining the cruise control without delaying the timing of suppressing the acceleration. [Brief description of the drawings]

[0014] [Figure 1] Schematic diagram of the driving control device [Diagram 2] Flowchart showing acceleration suppression control routine [Diagram 3] Flowchart showing steering angle correction value setting subroutine [Figure 4] Flowchart showing a target acceleration setting subroutine [Diagram 5] Conceptual diagram of turning area determination table [Figure 6] Conceptual diagram of steering angle correction value map [Figure 7] Conceptual diagram of target acceleration map [Figure 8] Timing chart showing increase in vehicle speed due to target acceleration [Figure 9] An explanatory diagram showing how to turn right at an intersection using ACC control. [Figure 10] FIG. 13 is an explanatory diagram showing how the vehicle runs on a curved road using ACC control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] An embodiment of the present invention will be described below with reference to the drawings. A cruise control device 1 shown in Fig. 1 is mounted on a host vehicle M (see Figs. 9 and 10). This cruise control device 1 includes a driving environment recognition unit 2 and an ACC control unit 3 as a cruise control section. This ACC control unit 3 and a forward driving environment recognition section 13 of the driving environment recognition unit 2, which will be described later, are composed of a microcomputer including a CPU, ROM, RAM, etc., and peripheral devices thereof, and the ROM stores fixed data such as a control program for realizing operations set for each system, data tables, data maps, etc.

[0016] The driving environment recognition unit 2 according to this embodiment includes a camera section 11, an image processing section 12, and a forward driving environment recognition section 13. The camera section 11 is a stereo camera consisting of a main camera 11a and a sub camera 11b, and the two cameras 11a and 11b are installed, for example, above the rearview mirror, at equal intervals with a predetermined baseline length from the center in the vehicle width direction to the left and right at a position close to the windshield. Each of the cameras 11a and 11b is provided with an imaging element such as a CCD or a CMOS, and the driving environment in front of the vehicle M, including the driving lane of the vehicle M, is captured and acquired by both imaging elements. The acquired driving environment information in front of the vehicle M is then subjected to predetermined image processing by the image processing section 12, and then output to the forward driving environment recognition section 13.

[0017] The forward driving environment recognition unit 13 recognizes the forward driving environment based on the image-processed driving environment information. This forward driving environment includes the road shape (the road curvature at the center of the dividing line dividing the left and right, and the width between the left and right dividing lines (lane width)) of the lane in which the host vehicle M is traveling (host vehicle driving lane), intersections, traffic light indications (lighting colors), road signs, and roadside obstacles (electric poles, utility poles, guardrails, fences, parked vehicles, etc.).

[0018] The forward driving environment recognized by the forward driving environment recognition unit 13 is read by the ACC control unit 3. In addition to the driving environment recognition unit 2, the input side of the ACC control unit 3 is connected to various sensors and switches that detect various parameters required for driving control, such as a turn signal switch 21 that blinks (ON) the turn signal on the side to be turned when turning right or left or changing lanes, a vehicle speed sensor 22 as a vehicle speed detection unit that detects the speed (vehicle speed) Vs [Km / h] of the host vehicle M, a yaw rate sensor 23 that detects the yaw rate acting on the host vehicle M, and a steering angle sensor 24 as a steering angle detection unit. Here, the steering angle sensor 24 detects the absolute value of the left and right steering angles (steering angle absolute value) |θst| [deg] based on the neutral position of the steering.

[0019] In addition, a control actuator 25 is connected to the output side of the ACC control unit 3. The control actuator 25 is a general term for a power actuator, an electric power steering (EPS) actuator, a brake actuator, and the like that realize the running of the host vehicle M. These are operated by a control signal from the control actuator 25.

[0020] Incidentally, a power actuator controls the output of a drive source such as an engine or an electric motor, an EPS actuator controls the drive of the EPS motor, and a brake actuator adjusts the brake hydraulic pressure supplied to the brake wheel cylinders provided on each wheel.

[0021] When the ACC control unit 3 detects a preceding vehicle to be followed that is traveling at a set vehicle speed or slower based on forward driving environment information recognized by the forward driving environment recognition section 13 of the driving environment recognition unit 2, the ACC control unit 3 executes a following driving control to follow the preceding vehicle. When a preceding vehicle to be followed is not detected, the ACC control unit 3 causes the vehicle to travel at a constant speed set by the driver in advance.

[0022] Furthermore, when the driver operates the steering wheel to turn the host vehicle M that has entered an intersection or the like to the right or left, or when the host vehicle M travels at high speed on a curved road, the ACC control unit performs acceleration suppression control so that the host vehicle M does not swerve outward. The acceleration suppression control executed by the ACC control unit 3 is specifically processed according to an acceleration suppression control routine shown in FIG.

[0023] This routine is executed at every predetermined calculation cycle. First, in step S1, the vehicle speed Vs detected by the vehicle speed sensor 22 and the absolute steering angle |θst| detected by the steering angle sensor 24 are read.

[0024] Next, the process proceeds to step S2, where the process refers to a turning area determination table based on the vehicle speed Vs and the steering angle absolute value |θst| to check whether the current running state is within a turning area that is subject to acceleration suppression control. Note that the processes in steps S1 and S2 correspond to the turning area determination unit of the present invention.

[0025] The concept of the turning area determination table is shown in Fig. 5. As shown in Fig. 5, the turning area is set to an area where the steering angle absolute value |θth| becomes smaller as the host vehicle speed Vs becomes higher, and conversely, the steering angle absolute value |θth| becomes larger as the host vehicle speed Vs becomes lower. In other words, the turning area set in this turning area determination table is an area showing a tendency that a large yaw rate is easily generated in the host vehicle M under the target acceleration set in the normal ACC control, and is set in advance by obtaining it through experiments or the like.

[0026] Situations in which an excessive yaw rate is likely to occur include, for example, when the vehicle speed Vs is low but the steering angle absolute value |θst| is relatively large, such as when turning right or left from an intersection, or when the vehicle is traveling on a curved road at high speed where understeer is likely to occur. Since the turning area determination table identifies the area in which an excessive yaw rate is likely to occur, even when the vehicle M is not at an intersection or cornering at high speed, the vehicle is subject to acceleration suppression control if the vehicle M is in the turning area.

[0027] And the driving condition is in the turning area. Inside If it is determined that the vehicle is in the turning area, the process proceeds to step S3. If the vehicle is not in the turning area, the process exits from the routine and normal ACC control is executed.

[0028] When it is determined that the host vehicle M is in the turning area and the process proceeds to step S3, the steering angle correction value θs is calculated and the process proceeds to step S4. 3 The process in step S2 is executed according to a steering angle correction value setting subroutine shown in FIG.

[0029] In this subroutine, first, in step S11, the absolute steering angle |θth| is time-differentiated to calculate the steering angular velocity ωst [deg / s]. The process in this step corresponds to the steering angular velocity detection unit of the present invention.

[0030] Next, the process proceeds to step S12, where the steering angle correction value map is referenced with an interpolation calculation based on the vehicle speed Vs and the steering angular velocity ωst, and the steering angle correction value θs [deg] is set, and the process proceeds to step S4 in Fig. 2. The process in this step corresponds to the steering angle correction value setting unit of the present invention.

[0031] The concept of the steering angle correction value map is shown in Fig. 6. As shown in the figure, in the steering angle correction value map, when the vehicle speed Vs and the steering angular velocity ωst are both low, the steering angle correction value θs is set to a small value, and as either the vehicle speed Vs or the steering angular velocity ωst increases, the steering angle correction value θs is set to a higher value. In other words, as the yaw rate tends to increase, the steering angle correction value θs is set to a larger value.

[0032] When the process proceeds to step S4 in FIG. 2, the target acceleration αo [m / s 2 ] is set, and the process proceeds to step S5. The process in step S4 is executed according to a target acceleration setting subroutine shown in Fig. 4. The process in this subroutine corresponds to the target acceleration setting unit of the present invention.

[0033] In this subroutine, first, in step S21, the steering angle correction value θs is added to the steering angle absolute value |θst| to calculate the steering angle θst. Next, the process proceeds to step S22, where the target acceleration map is referenced with an interpolation calculation based on the steering angle θst and the host vehicle speed Vs to calculate the host vehicle target acceleration αm [m / s 2 ] and proceed to step S23.

[0034] The concept of the target acceleration map is shown in Fig. 7. As shown in Fig. 7, the target acceleration map is set with a host vehicle target acceleration αm that gradually decreases as the host vehicle speed Vs and steering angle θst both increase. This steering angle θst is set by increasing the steering angle absolute value |θst| by the steering angle correction value θs. As described above, the steering angle correction value θs is set to a larger value as the yaw rate tends to increase. Therefore, even when driving at a low speed, if the driver operates the steering wheel at a relatively high speed, the host vehicle target acceleration αm, which is set based on the host vehicle speed Vs and steering angle θst, is set to a more suppressed value accordingly.

[0035] For example, as shown in Fig. 9, when the driver turns the vehicle M in a direction crossing an oncoming diagonal line at an intersection by steering (turning right in the figure) during driving under ACC control, if it is determined that the vehicle M is in a turning area, the ACC control unit 3 detects the steering angle absolute value |θst| and sets the steering angle correction value θs, so that the target acceleration αm of the vehicle during turning can be quickly suppressed in response to the steering operation of the driver. As a result, the vehicle M can be prevented from swerving due to an excessive yaw rate as shown by the dashed line in Fig. 9 during turning, and good driving stability can be obtained.

[0036] 10, the same applies when turning at high speed around a curved road, and when the driver operates the steering wheel to enter a curved road while driving under ACC control, the ACC control unit 3 sets the host vehicle target acceleration αm, which is set based on the steering angle absolute value |θst| detected by the steering angle sensor 24, to a suppressed value. As a result, it is possible to prevent the vehicle from swerving due to an excessive yaw rate, as shown by the dashed line in the figure.

[0037] Thereafter, in step S23, the ACC control unit 3 checks whether or not a preceding vehicle to be followed in the turning direction is recognized based on the forward driving environment information recognized by the forward driving environment recognition unit 13. If it is determined that there is a preceding vehicle to be followed, the process proceeds to step S24. On the other hand, if it is determined that there is no preceding vehicle to be followed, the process jumps to step S26.

[0038] When the process proceeds to step S24, a following target acceleration αs is set so that the host vehicle M follows the preceding vehicle. The process in this step corresponds to the following target acceleration setting unit of the present invention.

[0039] The following target acceleration αs is set based on the vehicle speed Vs, for example. Marking car The target vehicle distance is set by referring to a map based on the distance deviation (= target vehicle distance - vehicle distance) calculated from the difference between the vehicle distance and the preceding vehicle and the vehicle's relative speed (= preceding vehicle speed - vehicle speed) between the preceding vehicle and the vehicle itself. Note that the characteristics of this map are described in, for example, JP 2017-56765 A previously submitted by the present applicant, and therefore will not be described here.

[0040] Next, the process proceeds to step S25, where the two target accelerations αs and αm are compared to determine which one is smaller (select low). If αs≧αm, the process proceeds to step S26. If αs<αm, the process branches to step S27.

[0041] When the process proceeds to step S26, a new target acceleration, αo, is set to the host vehicle target acceleration αm, and the process proceeds to step S5 in Fig. 2. When the process branches to step S27, a new target acceleration, αo, is set to the following target acceleration αs, and the process proceeds to step S5 in Fig. 2.

[0042] Then, when the process proceeds to step S5 in Fig. 2, the vehicle speed Vs is compared with the target vehicle speed Vo, and if Vs>Vo, the process branches to step S6, the target acceleration αo is cleared (αo←0), and the process proceeds to step S7. If Vs≦Vo, the process proceeds to step S7. If a preceding vehicle to be followed is detected, the target vehicle speed Vo is set based on the preceding vehicle speed. If a preceding vehicle to be followed is not detected, the target vehicle speed Vo is set based on the road shape (curvature from the intersection in the traveling direction, curvature of a curved road, etc.) obtained from the forward driving environment information recognized by the forward driving environment recognition unit 13, or based on the set vehicle speed.

[0043] Then, the process proceeds to step S7, where the target acceleration αo is output and the routine ends. The ACC control unit 3 outputs a drive signal corresponding to the target acceleration αo to the control actuator 25, and causes the host vehicle M to travel at a predetermined acceleration. This allows the driver to travel stably through intersections and curved roads by operating the steering wheel alone, without depressing the accelerator pedal.

[0044] In this manner, according to the present embodiment, first, it is determined whether the host vehicle M is traveling in the turning area based on the host vehicle speed Vs and the steering angle absolute value |θst|. mosquito Check whether Turning When the vehicle is traveling in the area, a steering angle correction value θs is set based on the vehicle speed Vs and the steering angular velocity ωst, and this is added to the steering angle absolute value |θst| to set the steering angle θst.

[0045] Since the host vehicle target acceleration αm is set based on the steering angle θst and the host vehicle speed Vs, the host vehicle target acceleration αm is set based on the steering angle θst that is greater than the actual steering angle absolute value |θst|, and the host vehicle target acceleration αm has a relatively low value. As a result, as shown in Fig. 8, when the host vehicle M is turned by the driver's steering operation, a suppressed target acceleration αo(αm) is set immediately after steering is started.

[0046] Therefore, compared to the conventional target acceleration shown by the dashed line in FIG. 8, which suppresses the target acceleration after an excessive yaw rate occurs, the target acceleration αo (αm) set in this embodiment quickly suppresses the acceleration during cornering, making it possible to prevent an excessive yaw rate from occurring, and thereby obtaining good driving stability.

[0047] In this case, when the yaw rate detected by the yaw rate sensor 23 exceeds a preset threshold value while the host vehicle M is turning, it goes without saying that the target acceleration αo is set to a lower value as in the conventional case.

[0048] Furthermore, in this embodiment, the turning condition during ACC control is basically checked based on the vehicle speed Vs and the steering angle absolute value |θst|. Therefore, even in a situation where a map locator is not installed or information from the map locator cannot be obtained, a smooth turning condition can be obtained in response to the driver's steering operation while maintaining ACC control and without delaying the timing of suppressing acceleration.

[0049] The present invention is not limited to the above-described embodiment. For example, the driving environment recognition unit 2 may use a distance sensor such as a millimeter wave radar, a sonic radar, or a LiDAR (Light detection and Ranging) instead of a stereo camera, or may use a combination of these with a monocular camera. [Explanation of symbols]

[0050] 1...Traction control device, 2... Driving environment recognition unit, 3...ACC control unit, 11…Camera section, 11a…Main camera, 11b…Sub camera, 12...Image processing unit, 13...Front driving environment recognition unit, 21...Wind signal switch, 22...Vehicle speed sensor, 23...Yaw rate sensor, 24...Steering angle sensor, 25...Control actuator, M…own vehicle, Vo...Target vehicle speed, Vs…Vehicle speed, αm…Target acceleration of own vehicle, αo…target acceleration, αs: target acceleration, θs: steering angle correction value, θst: steering angle, ωst: Steering angular velocity

Claims

1. a steering angle detection unit that detects a steering angle absolute value, which is an absolute value of a rotation angle of a steering wheel of a vehicle relative to a neutral position of the steering wheel in accordance with a steering operation by a driver; a vehicle speed detection unit that detects a speed of the host vehicle; a cruise control unit that causes the host vehicle to travel at a constant speed at a set vehicle speed or to follow a preceding vehicle; In a driving control device having a steering angular velocity detection unit that calculates a steering angular velocity based on the absolute steering angle value detected by the steering angle detection unit, The cruise control unit a steering angle correction value setting unit that sets a steering angle correction value that is a positive value and that increases as the steering angular velocity increases and as the speed of the host vehicle increases, based on the steering angular velocity detected by the steering angular velocity detection unit and the speed of the host vehicle detected by the vehicle speed detection unit; a target acceleration setting unit that sets a target acceleration of a cruise control based on an added steering angle set by adding the steering angle correction value set by the steering angle correction value setting unit to the steering angle absolute value detected by the steering angle detection unit and a speed of the host vehicle detected by the vehicle speed detection unit so that the target acceleration becomes smaller as the added steering angle increases and becomes smaller as the speed of the host vehicle increases; A driving control device comprising:

2. The cruise control unit a turning area determination unit that determines whether or not the speed of the host vehicle and the absolute steering angle value are within a turning area indicating a predetermined range, based on the absolute steering angle value detected by the steering angle detection unit and the speed of the host vehicle detected by the vehicle speed detection unit, When the turning area determination unit determines that the steering angle absolute value and the speed of the host vehicle are within the turning area, an acceleration suppression control is performed to suppress the target acceleration, When the turning area determination unit determines that the steering angle absolute value and the speed of the host vehicle are not within the turning area, the acceleration suppression control is not performed.

2. The driving control device according to claim 1.

3. The cruise control unit further includes a driving environment recognition unit that recognizes a driving environment in front of the vehicle. The vehicle control system further includes a following target acceleration setting unit that sets a following target acceleration for following the preceding vehicle when the driving environment recognition unit detects the preceding vehicle to be followed by the host vehicle, and the target acceleration setting unit compares the target acceleration with the following target acceleration set by the following target acceleration setting unit and sets the smaller value as a new target acceleration.

3. The driving control device according to claim 2.

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