Vehicle driving control device

Abstract

To enable a vehicle in a stopped state on a road shoulder to start moving while minimizing an influence on a traffic flow without relying excessively on detection performance of a sensor.SOLUTION: In a start mode which enables an own vehicle 1 in a stopped state on a road shoulder to start: (i) in a case where another vehicle 3 is detected in a rear detection region, the own vehicle is caused to wait until the other vehicle 3 passes when an estimated deceleration degree d required for the other vehicle 3 due to starting of the own vehicle 1 is equal to or larger than a predetermined threshold or the own vehicle 1 is caused to start when the estimated deceleration degree d required for another vehicle 3 is less than the predetermined threshold; and (ii) in a case where another vehicle is not detected in the rear detection region, the own vehicle 1 is caused to start moving with a target route set to a first lateral position P1 closer to the road shoulder than a center of a traffic lane of the own vehicle, to accelerate while traveling along the first lateral position P1, and then to transit to travel for maintaining a second lateral position P2 with the target route set to the second lateral position P2 (or the center of the traffic lane of the own vehicle) close to the center of the traffic lane of the own vehicle while the own vehicle is in a state of being accelerated to a predetermined speed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle travel control device, and more particularly to control of starting a vehicle from a state where the vehicle is parked on the shoulder of a road. [Background technology]

[0002] Various driving control systems aimed at reducing the burden on drivers and supporting safe driving are being put into practical use. For example, Patent Document 1 discloses a driving support method that predicts the situation around a vehicle and supports driving based on the prediction results, in which a rear vehicle located behind the vehicle is detected, the behavior of the rear vehicle is predicted based on the environment in which the rear vehicle is located, and the vehicle starts moving or waits for the rear vehicle to pass before starting. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-197966 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because the sensor's detection range is limited and road conditions are diverse, if a vehicle approaches from behind at high speed from outside the sensor's detection range after the vehicle has started moving, there is a risk of problems occurring, such as causing the vehicle behind to suddenly brake.

[0005] The present invention has been made in consideration of the above-described circumstances, and its purpose is to provide a driving control device that can execute control to start a vehicle from a state where the vehicle is stopped on the shoulder of the road, without relying excessively on the detection capabilities of sensors, and with minimal impact on traffic flow. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides: A vehicle travel control device that recognizes a road environment based on detection information from an external sensor, generates a target route, and performs speed control and steering control so as to follow the target route, A start mode in which the vehicle starts from a state in which the vehicle is stopped on the shoulder of the road, (i) when another vehicle is detected within the detection range behind the host vehicle, if the deceleration estimated to be required for the other vehicle due to the host vehicle starting is equal to or greater than a predetermined threshold, wait for the other vehicle to pass, and if the deceleration estimated to be required for the other vehicle is less than the predetermined threshold, start the host vehicle; (ii) A vehicle driving control device having a start mode that executes a first step of setting the target route to a first lateral position closer to the shoulder than the center of the vehicle's lane, starting the vehicle, and accelerating while traveling along the first lateral position, if no other vehicle is detected within the rear detection range, and then a second step of setting the target route to a second lateral position closer to the center of the vehicle's lane while accelerating to a predetermined speed, and transitioning to traveling while maintaining the second lateral position. [Effects of the Invention]

[0007] By having the above-described starting mode, the vehicle driving control device of the present invention can maximize the opportunity to start without causing sudden braking in other vehicles even when other vehicles are detected in the detection range behind, and if no other vehicles are detected in the detection range behind, it accelerates while traveling along the first lateral position close to the shoulder immediately after starting.Therefore, even if a rear vehicle approaches the sensor's detection range at high speed after starting, not only is there sufficient driving space in the center of the lane, but the vehicle can also decelerate from the first lateral position close to the shoulder and immediately stop on the shoulder, thereby avoiding sudden braking in the rear vehicle and allowing the vehicle to start with minimal impact on traffic flow without relying excessively on the detection capabilities of the sensor. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a block diagram showing a vehicle driving control device. [Figure 2] FIG. 10 is a schematic diagram showing a starting mode from a state where the vehicle is stopped on the shoulder of the road. [Figure 3] FIG. 10 is a schematic diagram showing a speed estimation of a hypothetical approaching vehicle after starting. [Figure 4] 10 is a flowchart showing a starting mode. [Figure 5] 10A is a graph showing the speed of the host vehicle and the estimated speed of a virtual approaching vehicle, and FIG. 10B is a graph showing the estimated inter-vehicle distance between the host vehicle and the virtual approaching vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the driving control device of the vehicle 1 is equipped with a control system 10 including a group of input devices consisting of an external sensor 21, an internal sensor 22, a positioning system 23, etc., and a vehicle operation determination unit 13 that determines a target route for the vehicle 1 based on road environment information 11 and vehicle information 12 obtained through these devices, and executes lateral control 14 and longitudinal control 15.

[0010] The external sensor 21 is composed of a group of sensors selected from front and rear radars (millimeter wave radars) that detect objects (position, relative speed) in front of and behind the vehicle, image sensors such as monocular cameras and stereo cameras that capture images of the road environment in front of and behind the vehicle, and LIDAR (laser scanner) that acquires the road environment around the vehicle as 3D point cloud data.

[0011] For example, as shown in FIG. 2, the external sensor 21 includes a forward sensor 211 (radar, image sensor or laser scanner), a rear sensor 212 (radar, image sensor), a front side sensor 213 and a rear side sensor 214 (radar, image sensor or laser scanner), only the right side of which is shown in FIG. 2, and are arranged so that the surroundings of the vehicle 1 are included in the detection range.

[0012] The internal sensors 22 are composed of a group of multiple sensors that determine the motion state of the vehicle 1, such as a vehicle speed sensor, an acceleration sensor, a yaw rate sensor, a steering angle sensor, an accelerator sensor, and a brake sensor.These detection values ​​are acquired by the control system 10 via in-vehicle communication (in-vehicle network) and form vehicle information 12 as state values ​​that indicate the current motion state of the vehicle 1.

[0013] The positioning system 23 is implemented as a satellite positioning system (GNSS sensor) for acquiring position information of the vehicle 1, and constitutes a driving plan system (navigation system) that uses map data and traffic information in combination to provide route guidance based on a driving plan. Traffic information such as lane regulations and speed limits related to the position information is acquired through broadcast information distribution, V2I road-to-vehicle communication, mobile communication using a cellular communication network, etc., and furthermore, information on traffic signals and traffic signs is acquired from information detected by the external sensor 21.

[0014] The driving planning system provides route guidance based on a pre-determined driving plan, referring to traffic information related to the destination and route information input using an HMI device or wireless communication terminal, and specifies driving modes according to the situation, such as speed control, lane keeping and distance maintenance control, lane changes, merging, and right and left turns, to enable autonomous driving in accordance with traffic rules.

[0015] The control system 10 includes a road structure recognition unit that recognizes road structures (road dividing lines, guardrails, medians, etc.) from image data or 3D point cloud data acquired by an external sensor 21, and a road environment estimation unit that generates road environment information 11 that is updated at a predetermined frame rate by detecting preceding vehicles and obstacles in the vehicle's lane using radar.

[0016] The control system 10 includes a vehicle operation determination unit 13 that generates a target route based on road environment information 11 and vehicle information 12, a lateral control unit 14 that outputs a steering angle command to the steering unit 33 to provide a target steering angle for causing the vehicle 1 to follow the target route, and a longitudinal control unit 15 that outputs a speed command (acceleration / deceleration command) to the drive unit 34 and the braking unit 35 to achieve the target speed, as control units.

[0017] The vehicle operation decision unit 13 has driving modes such as speed control, distance control, lane keeping, lane changing, merging and turning right or left based on the road environment information 11 and vehicle information 12, and is configured to be able to perform vehicle motion control optimized for each driving scene and associated blinker flashing.

[0018] For example, the road environment estimation unit constituting the road environment information 11 has the function of recognizing the lane (driving lane) of the vehicle 1 based on image data or 3D point cloud data acquired by the forward sensor 211 constituting the external sensor 21, and estimating the center (center line) of the lane (driving lane) from the road dividing lines (or alternative structures) on both sides of the driving lane, and the vehicle operation determination unit 13 performs lane center keeping driving by setting a target route in the center of the lane and performing steering control.

[0019] In addition, the road environment estimation unit that constitutes the road environment information 11 has the function of recognizing road dividing lines (or alternative structures) of adjacent lanes and estimating the center of the adjacent lanes, and the vehicle operation determination unit 13 executes lane changes by setting a target route at the forward center of the adjacent lane and performing steering control when it has been confirmed in the road environment information 11 that no other vehicles exist within a specified range of the adjacent lane.

[0020] Furthermore, the control system 10 includes a start control unit 17 that executes a start mode in which the vehicle 1 starts from the shoulder of the road, based on rear approaching vehicle information 16, by using a rear sensor 212 (rear radar) that constitutes the external sensor 21. The start mode will be described later.

[0021] Each control unit constituting the control system 10 described above is implemented as a computer (ECU) equipped with a ROM (flash memory) that stores programs operable to execute the respective functions, a CPU that performs calculation processing, a RAM into which the programs are read and which serves as the CPU's working area and temporary storage area for the calculation results, and an input / output interface.

[0022] The steering unit 33 is composed of a steering mechanism including steering wheels and a steering actuator (an EPS motor that constitutes an electric power steering system). The drive unit 34 is composed of an internal combustion engine and an engine controller in the case of an internal combustion engine vehicle, a motor generator and a motor controller in the case of an electric vehicle, and these and a hybrid controller in the case of a hybrid vehicle. The braking unit 35 is composed of a brake device for braking each wheel, a brake actuator, a brake controller (ABS / ESC controller), etc.

[0023] FIG. 4 is a flowchart showing the flow of processing in the start mode from a roadside stop state, and the start mode will be described in detail below with reference to the drawings.

[0024] As shown in FIG. 2, when vehicle 1 is started from a state where it is parked on the shoulder 50, the driver or user of vehicle 1 performs a trigger operation (such as operating the turn signal lever or touch panel) to indicate the intention to start, or when it is determined that the vehicle 1 is ready to start based on detection information from an in-vehicle monitor or the like, the vehicle switches to a start mode and starts flashing the turn signals to indicate to traffic that vehicle 1 intends to start (step 100).

[0025] At the same time, traffic information such as lane regulations and speed limits related to the position information of the vehicle 1 acquired by the positioning system 23 is acquired, and based on the forward road environment information acquired by the front sensor 211 and the front side sensor 213 that constitute the external sensor 21, detection of other vehicles and obstacles on the road ahead of the vehicle 1 is performed, and based on the rear road environment information acquired by the rear sensor 212 (rear radar) that constitutes the external sensor 21, detection of vehicles approaching from behind in the own lane 5 is performed (step 101).

[0026] (1) When a following vehicle is detected When it is confirmed that there are no obstacles or specific driving situations ahead on the road that would hinder starting, and a vehicle 3 approaching from behind is detected (step 102; YES), the deceleration d required for the following vehicle 3 while accelerating to the target speed after vehicle 1 starts is estimated from the speed V and distance (inter-vehicle time) of the following vehicle 3 detected by the rear sensor 212 (rear radar) (step 103).

[0027] (1-1) If it is determined that the deceleration d estimated to be required for the following vehicle 3 due to the start of vehicle 1 is not less than a predetermined value, i.e., is equal to or greater than a predetermined threshold (step 104; NO), the vehicle 1 does not start, but waits until the following vehicle 3 has passed, and after confirming that the following vehicle 3 has passed based on the detection information of the external sensor 21, the process returns to step 101 and vehicle 1 is restarted.

[0028] (1-2) If it is determined that the deceleration d that is estimated to be necessary for the following vehicle 3 due to the start of the vehicle 1 is less than a predetermined value (step 104; YES), the vehicle 1 is started (step 105).

[0029] In this case, the following vehicle 3 will not be required to suddenly decelerate between the time when vehicle 1 starts and the time when it accelerates to the target speed at a predetermined acceleration, and the presence of the following vehicle 3 means that there cannot be any other following vehicles that will suddenly approach from behind the detection range of the rear sensor 212 (rear radar), so after vehicle 1 starts, the target route is set to the center of the lane (second lateral position P2), and the vehicle accelerates while traveling in the center of the lane (step 106).

[0030] Thereafter, when the target speed is reached (step 107; YES), the start mode is terminated and the mode shifts to normal driving mode (step 108). If the vehicle catches up with the preceding vehicle before reaching the target speed, the mode shifts to following the preceding vehicle while maintaining a predetermined inter-vehicle time.

[0031] (2) When a following vehicle is not detected If it is confirmed that there are no obstacles or specific driving situations ahead on the road that would hinder starting, and no vehicle approaching from behind is detected (step 102; NO), as shown in Figure 2, first, the target route is set to a first lateral position P1 that is closer to the shoulder 50 than the center of the own lane, and the vehicle is started (step 109), and the vehicle accelerates while traveling along the first lateral position P1 (step 110).

[0032] The first lateral position P1 is determined based on the road environment information 11 so that the center of the vehicle 1 is maintained at a predetermined distance consisting of 1 / 2 the vehicle width and a margin, with the shoulder 50 (outer line) of the own lane 5 as the reference, or is determined as a predetermined lateral deviation (offset amount) with the center of the own lane as the reference so that the margin is secured.

[0033] (2-1) Immediately after vehicle 1 starts moving, or while vehicle 1 is traveling along the first lateral position P1, a rear vehicle appears approaching at high speed within the detection range of rear sensor 212 (rear radar), and if it is determined from the speed and distance (inter-vehicle time) of this rear vehicle that the deceleration estimated to be required by the rear vehicle while vehicle 1 is accelerating to the target speed is equal to or greater than a predetermined value (step 111; YES), the target route is set closer to shoulder 50, the vehicle decelerates, and stops on shoulder 50 (step 116), allowing the rear vehicle to pass, and after confirming the passage of the rear vehicle based on the detection information of external sensor 21, the process returns to step 101 and vehicle 1 is restarted.

[0034] (2-2) On the other hand, after vehicle 1 starts moving, while traveling along first lateral position P1, if no other vehicle is detected rapidly approaching from behind, a hypothetical approaching vehicle is assumed and hypothetical approaching vehicle calculation 18 is executed to dynamically determine the timing of transition from first lateral position P1 to traveling maintaining second lateral position P2 (or the center of the lane).

[0035] That is, the speed Vv of the imaginary approaching vehicle is estimated based on the road environment (step 112), and an imaginary approaching vehicle calculation 18 is executed to determine the closest distance to vehicle 1 when the imaginary approaching vehicle decelerates from the estimated speed Vv at a predetermined deceleration dv (step 113). When the closest inter-vehicle distance becomes equal to or greater than a predetermined value (step 114; YES), the target route is set to a second lateral position P2 closer to the center of the own lane, and the road is changed to the second lateral position P2 (or the center of the lane) (step 115).

[0036] For example, as shown in Figure 3, for a speed V1 and acceleration a1 of a vehicle 1 traveling at a first lateral position P1, the estimated speed Vv of a hypothetical approaching vehicle 4v traveling at a position within the detection range Y+α of the rear sensor 212 (rear radar) of the vehicle 1 is determined from the speed limit Z in the road environment and the variable factor β using the following equation. Estimated speed Vv = speed limit Z + variable factor β

[0037] Here, the speed limit Z in the road environment is acquired by referring to the position information of the vehicle 1 acquired by the positioning system 23, map data or traffic information.

[0038] The following are examples of the variable factor β that depends on the road environment. The variable factor β (km / h) may be the maximum value of each factor, or may be a dimensional matrix with the number of factors. Alternatively, the dominant factor may be selected for each driving situation. Road shape: straight line β=30; curve β=20 Road type: Community road β=20; Main road β=30 Number of lanes: 1 lane β=20; 2 or more lanes β=30 Road width: Less than 3m β=20; More than 3m β=30

[0039] The closest approaching distance Dm between the virtual approaching vehicle 4v, traveling at the estimated speed Vv as described above, and the vehicle 1 is calculated when the virtual approaching vehicle 4v slows down at a non-hazardous deceleration dv (for example, -0.05 G equivalent to engine braking or -0.1 G equivalent to light braking), and the vehicle 4v continues traveling in the first lateral position P1 while the closest approaching distance Dm is less than the safe inter-vehicle distance Ds, and moves to the second lateral position P2 when the closest approaching distance Dm becomes equal to or greater than the safe inter-vehicle distance Ds.

[0040] Once the closest approach distance Dm is equal to or greater than the safe inter-vehicle distance Ds, even if a rear vehicle approaches from outside the detection range of the rear sensor 212 (rear radar), the safe inter-vehicle distance Ds can be maintained without the need for sudden deceleration, so it can be assumed that changing lanes to the second lateral position P2 closer to the center of the own lane will not affect traffic flow.

[0041] For example, as shown in Figure 5(a), when the host vehicle 1 accelerates to a speed Vt = 40 km / h at +0.111 G, the hypothetical approaching vehicle 4v is assumed to decelerate from a rear position corresponding to the detection distance D0 = 80 m of the rear sensor 212 at a speed Vv = 70 km / h to a speed Vt = 40 km / h at a deceleration dv = -0.06 G equivalent to engine braking.

[0042] Based on the start of vehicle 1, the timing t0 at which the virtual approaching vehicle 4v begins to decelerate is the same as the start of vehicle 1, and t2 to t8 indicate the cases 2 to 8 seconds later.As shown in Figure 5(b), if vehicle 1 moves to the second lateral position P2 5 seconds after starting to move from the first lateral position P1, a safe inter-vehicle distance Ds = 22 m can be ensured at the closest approach distance Dm.

[0043] In addition, the vehicle 1 can be configured to move from the first lateral position P1 to the second lateral position P2 (or the center of the lane) when it accelerates to the target vehicle speed or a speed that is a predetermined percentage of the target vehicle speed (for example, 90% of the target vehicle speed).

[0044] As described above, according to the start mode of the present invention, even if a following vehicle is detected within the detection range of the rear sensor 212, it is possible to maximize the opportunity to start without causing the following vehicle to suddenly brake.

[0045] On the other hand, if no following vehicle is detected within the detection range of the rear sensor 212, the vehicle accelerates while traveling along the first lateral position P1 close to the shoulder 50 immediately after starting. Therefore, even if a following vehicle appears approaching the detection range of the rear sensor 212 at high speed after starting, the vehicle can decelerate from the first lateral position P1 close to the shoulder 50 and immediately stop on the shoulder 50, leaving space in the center of the lane 5 for steering to avoid the vehicle, thereby avoiding sudden braking by the vehicle behind.

[0046] In particular, it has the advantage of being able to handle cases where the detection range of the rear sensor 212 is limited due to the presence of a curve with poor visibility (blind corner) behind the vehicle or a stopped vehicle, or when a following vehicle appears due to a lane change from an adjacent lane.

[0047] Furthermore, while traveling at the first lateral position P1, a hypothetical approaching vehicle 4v is assumed to approach from outside the detection range of the rear sensor 212, and when the closest inter-vehicle distance Dm between the virtual approaching vehicle 4v and the host vehicle 1, which is calculated from the estimated speed Vv and deceleration dv of the virtual approaching vehicle 4v determined based on the road environment, and the speed V1 and acceleration a1 of the host vehicle 1, becomes equal to or greater than the safe inter-vehicle distance Ds, the vehicle moves to the second lateral position P2 closer to the center of the lane. This allows the vehicle to move to the second lateral position P2 at an appropriate timing depending on the road environment, and travel at the first lateral position P1 can be kept to a necessary minimum.

[0048] Therefore, the cruise control device according to the present invention does not rely excessively on the detection capability of the rear sensor 212, and can start the vehicle 1 while minimizing the impact on traffic flow.

[0049] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made based on the technical concept of the present invention. [Explanation of symbols]

[0050] 1 vehicle 3. Following vehicles 4v Virtual Approaching Vehicle 5 lanes (travel lanes) 10. Control System 11 Track environment information 12 Vehicle Information 13 Vehicle operation decision unit 14 Lateral control section 15 Vertical control section 16 Rear approaching vehicle information 17 Starting control unit 18 Virtual approaching vehicle calculation 21 External Sensor 22 Internal Sensors 23 Positioning System 50 Shoulder

Claims

1. A vehicle travel control device that recognizes a road environment based on detection information from an external sensor, generates a target route, and performs speed control and steering control so as to follow the target route, A start mode in which the vehicle starts from a state in which the vehicle is stopped on the shoulder of the road, (i) when another vehicle is detected within a detection range behind the host vehicle, if the deceleration estimated to be required for the other vehicle due to the host vehicle starting is equal to or greater than a predetermined threshold, wait for the other vehicle to pass, and if the deceleration estimated to be required for the other vehicle is less than the predetermined threshold, start the host vehicle; (ii) A vehicle driving control device having a starting mode that, if no other vehicle is detected within the rear detection range, executes a first step of setting the target route to a first lateral position closer to the shoulder than the center of the vehicle's lane, starting the vehicle, and accelerating while traveling along the first lateral position, and then, after accelerating to a predetermined speed, sets the target route to a second lateral position closer to the center of the vehicle's lane, and transitions to traveling while maintaining the second lateral position.

2. 2. A vehicle driving control device according to claim 1, configured such that, when a second vehicle approaching from behind is detected while the vehicle is traveling in the first step, if the deceleration estimated to be required for the second vehicle based on the traveling state of the vehicle and the speed of the second vehicle is less than a predetermined threshold, the vehicle continues to accelerate, and if the deceleration estimated to be required for the second vehicle is equal to or greater than the predetermined threshold, the vehicle changes the target route toward the shoulder of the road, decelerates and stops, and waits for the second vehicle to pass.

3. The start mode is configured to, in a state where no other vehicle approaching from behind is detected during traveling in the first step, assume a virtual approaching vehicle approaching from outside the detection range behind, and when the speed of the virtual approaching vehicle determined based on the road environment and the closest inter-vehicle distance between the virtual approaching vehicle and the subject vehicle calculated from the speed and acceleration of the subject vehicle become equal to or greater than a predetermined value, execute the second step even if the speed is less than the predetermined value, the speed of the virtual approaching vehicle determined based on the road environment is determined from a speed limit in the road environment and a variable factor dependent on the road environment, the variable factor being at least one selected from the group consisting of a road shape, a road type, a number of lanes, and a road width; 3. A vehicle driving control device according to claim 1 or 2.

4. 4. The vehicle cruise control device according to claim 1, wherein the second lateral position is the center of a lane.

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