JP7599964B2 - Vehicle driving control method and driving control device - Google Patents

Description

The present invention relates to a vehicle driving control method and a driving control device.

A conventional method for recognizing road information is known that detects lane markers in the lane in which the vehicle is traveling, detects lane markers and lane widths in lanes adjacent to this lane, and estimates the lane marker that pairs with the nearby lane marker in the lane after the lane change based on lane markers common to the lane before and after the lane change and the lane width of the lane after the lane change (see Patent Document 1).

JP 2017-134664 A

However, the above-mentioned conventional road information recognition method has a problem in that when estimating the lane markers of the lane after a lane change, if a nearby lane marker cannot be detected, the corresponding distant lane marker cannot be estimated either.

The problem that this invention aims to solve is to provide a vehicle driving control method and driving control device that can recognize lane markers after a lane change when changing lanes through autonomous driving control.

The present invention solves the above problem by estimating the shape of the road on which the vehicle is currently traveling based on side lane marker information detected on the sides of the vehicle, and generating a control command value for autonomous lane change control based on the estimated road shape, the detected traveling state of the vehicle, and the generated target trajectory.

According to the present invention, when changing lanes using autonomous driving control, it is possible to recognize lane markers after the lane change.

1 is a block diagram showing an embodiment of a vehicle cruise control device according to the present invention; FIG. 2 is a front view showing a part of the input device of FIG. 1 . 2 is a plan view showing an example of lane change control of the driving control device of FIG. 1; 2 is a plan view showing an example of mounting a front camera, a side camera, and a rear camera included in the sensor of FIG. 1. 1A and 1B are plan views showing an example of lane change control using a forward camera. 2 is a block diagram showing an example of a lane change control unit included in the control device of FIG. 1 . 7 is a diagram illustrating an example of processing executed by a lane change target trajectory generating unit in FIG. 6; 1A and 1B are plan views showing an example of lane change control using a front camera and a side camera, respectively. 7 is a diagram illustrating an example of a process executed by a road curvature estimation unit in FIG. 6; 7 is a diagram illustrating an example of processing executed by a first follow-up command value generating unit and a second follow-up command value generating unit in FIG. 6 . 7 is a flowchart showing an example of a control process executed by the lane change control unit of FIG. 6 .

Configuration of the driving control device
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing the configuration of a vehicle cruise control device 1 according to this embodiment. The cruise control device 1 of this embodiment is also an embodiment for carrying out a vehicle cruise control method according to the present invention.

As shown in FIG. 1, the driving control device 1 of this embodiment includes a sensor 11, a vehicle position detection device 12, a map database 13, in-vehicle equipment 14, a navigation device 15, a presentation device 16, an input device 17, a drive control device 18, and a control device 19. These devices are connected, for example, by a CAN (Controller Area Network) or other in-vehicle LAN, and can send and receive information between them.

The sensor 11 detects the driving state of the vehicle. For example, the sensor 11 may be a front camera that captures an image in front of the vehicle, a side camera that captures an image of the left and right sides of the vehicle, a rear camera that captures an image of the rear of the vehicle, a front radar that detects obstacles in front of the vehicle, a rear radar that detects obstacles behind the vehicle, a side radar that detects obstacles on the left and right sides of the vehicle, a vehicle speed sensor that detects the vehicle speed, a touch sensor (capacitive sensor) that detects whether the driver is holding the steering wheel, and an in-vehicle camera that captures an image of the driver. The sensor 11 may be configured to use one of the above-mentioned multiple sensors, or may be configured to use a combination of two or more types of sensors. The detection results of the sensor 11 are output to the control device 19 at predetermined time intervals.

The vehicle position detection device 12 includes a GPS unit, a gyro sensor, a vehicle speed sensor, and the like. The vehicle position detection device 12 detects radio waves transmitted from multiple satellite communications by the GPS unit, and periodically acquires position information of the target vehicle (the vehicle itself). The vehicle position detection device 12 also detects the current position of the target vehicle based on the acquired position information of the target vehicle, angle change information acquired from the gyro sensor, and vehicle speed acquired from the vehicle speed sensor. The position information of the target vehicle detected by the vehicle position detection device 12 is output to the control device 19 at predetermined time intervals.

The map database 13 is a memory that stores three-dimensional high-precision map information including the position information of various facilities and specific points, and is accessible from the control device 19. The three-dimensional high-precision map information is three-dimensional map information based on the road shape detected when an actual road is driven on using a data acquisition vehicle. The three-dimensional high-precision map information is map information that is associated with detailed and highly accurate position information, such as curved roads and the size of the curve (e.g., curvature or curvature radius), road junctions, branching points, toll gates, and positions where the number of lanes decreases, as well as map information, as three-dimensional information. However, the map information stored in the map database of the present invention is not limited to only three-dimensional high-precision map information, and may be other map information.

The in-vehicle devices 14 are various devices mounted on the vehicle and are operated by the driver. Such in-vehicle devices include the steering wheel, accelerator pedal, brake pedal, turn signals, wipers, lights, the horn, and other specific switches. When the in-vehicle devices 14 are operated by the driver, they output operation information to the control device 19.

The navigation device 15 obtains the current position information of the vehicle from the vehicle position detection device 12, and displays the vehicle's position on a display or the like by overlaying it on map information for guidance. The navigation device 15 also has a navigation function that, when the driver inputs a destination, calculates a route to the destination and guides the driver along the set route. With this navigation function, the navigation device 15 displays the route to the destination on the map on the display, and notifies the driver of recommended driving behavior along the route by voice or the like.

The presentation device 16 includes various displays such as a display provided in the navigation device 15, a display built into the rearview mirror, a display built into the meter section, and a head-up display projected on the windshield. The presentation device 16 also includes devices other than displays, such as speakers in an audio device and a seat device with an embedded vibrator. The presentation device 16 notifies the driver of various presentation information according to the control of the control device 19.

The input device 17 is, for example, a button switch that allows input by manual operation by the driver, a touch panel arranged on a display screen, or a microphone that allows input by the driver's voice. In this embodiment, the driver can input setting information for the presentation information presented by the presentation device 16 by operating the input device 17. Figure 2 is a front view showing a part of the input device 17 of this embodiment, and shows an example consisting of a group of button switches arranged on the spokes of a steering wheel, etc.

The illustrated input device 17 is a button switch used to set the ON/OFF of the autonomous driving control function (autonomous speed control function and autonomous steering control function) of the control device 19. Details of the autonomous driving control function including the autonomous speed control function and the autonomous steering control function will be described later. The input device 17 of this embodiment includes a main switch 171, a resume/accelerate switch 172, a set/coast switch 173, a cancel switch 174, a vehicle distance adjustment switch 175, and a lane change assistance switch 176.

The main switch 171 is a switch for turning on/off the power supply of the system that realizes the autonomous speed control function and the autonomous steering control function of the control device 19. The resume/accelerate switch 172 is a switch for performing a resume operation such as restarting the autonomous speed control function at the set speed before turning off the autonomous speed control function once and then turning it off, or restarting the autonomous speed control function by the control device 19 after stopping to follow a preceding vehicle (another vehicle traveling in front of the vehicle in the same lane as the vehicle itself. The same applies hereinafter in this specification), or an accelerate operation for increasing the set speed. The set/coast switch 173 is a switch for performing a set operation for starting the autonomous speed control function at the traveling speed, or a coast operation for decreasing the set speed. The cancel switch 174 is a switch for turning off the autonomous speed control function. The vehicle distance adjustment switch 175 is a switch for setting the vehicle distance from the preceding vehicle, and is a switch for selecting one of multiple settings such as short distance, medium distance, and long distance. The lane change assistance switch 176 is a switch for accepting the start of a lane change when the control device 19 confirms with the driver that the lane change should be started. After accepting the start of a lane change, the lane change assistance switch 176 can be pressed for longer than a predetermined time to cancel the acceptance of the lane change suggestion made by the control device 19.

In addition to the button switches shown in FIG. 2, the turn signal lever of the turn signal or other switches of the in-vehicle equipment 14 can be used as the input device 17. For example, when the control device 19 suggests whether to change lanes through autonomous control, the driver can turn on the turn signal switch to input consent or permission to the lane change. Also, when the control device 19 suggests whether to change lanes through autonomous control, the driver can operate the turn signal lever to change lanes in the direction in which the turn signal lever is operated, rather than the proposed lane change. The setting information input by the input device 17 is output to the control device 19.

The drive control device 18 controls the running of the host vehicle in various ways. For example, when the host vehicle runs at a constant speed at a set speed due to the autonomous speed control function, the drive control device 18 controls the operation of the drive mechanism (including the operation of the internal combustion engine in an engine vehicle, the operation of the driving motor in an electric vehicle system, and the torque distribution between the internal combustion engine and the driving motor in a hybrid vehicle) and the brake operation in order to accelerate and decelerate the host vehicle to the set speed, and to maintain the running speed. In addition, when the host vehicle runs following a preceding vehicle due to the autonomous speed control function, the drive control device 18 controls the operation of the drive mechanism and the brake operation to achieve the acceleration/deceleration and running speed so that the distance between the host vehicle and the preceding vehicle is constant.

The drive control device 18 also controls the operation of the steering actuator in addition to the above-mentioned drive mechanism and brake operation control by the autonomous steering control function, thereby performing steering control of the host vehicle. For example, when performing lane keeping control by the autonomous steering control function, the drive control device 18 detects lane markers in the host lane (the lane in which the host vehicle is traveling; the same applies hereinafter in this specification) and controls the host vehicle's traveling position in the width direction so that the host vehicle travels at a predetermined position within the host lane. When performing lane change assistance by the lane change assistance function described later, the drive control device 18 controls the host vehicle's traveling position in the width direction so that the host vehicle changes lanes. Furthermore, when performing right/left turn assistance by the autonomous steering control function, the drive control device 18 performs driving control to turn right or left at an intersection or the like. The drive control device 18 controls the driving of the host vehicle according to instructions from the control device 19 described later. Other known methods can also be used as driving control methods by the drive control device 18.

The control device 19 includes a ROM (Read Only Memory) that stores a program for controlling the traveling of the vehicle, a CPU (Central Processing Unit) that executes the program stored in the ROM, and a RAM (Random Access Memory) that functions as an accessible storage device. Note that, as the operating circuit, an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), etc. can be used instead of or in addition to the CPU (Central Processing Unit).

<Functions Realized by the Control Device 19>
The control device 19 executes a program stored in the ROM by the CPU, thereby realizing a driving information acquisition function for acquiring information regarding the driving state of the vehicle, a driving scene determination function for determining the driving scene of the vehicle, and an autonomous driving control function for autonomously controlling the driving speed and/or steering of the vehicle. Each function of the control device 19 will be described below.

The driving information acquisition function of the control device 19 is a function that allows the control device 19 to acquire driving information related to the driving state of the vehicle. For example, the control device 19 acquires image information of the outside of the vehicle captured by the front camera, rear camera, and side camera of the sensor 11 as driving information. The control device 19 also acquires the detection results of the front radar, rear radar, and side radar as driving information. Furthermore, the control device 19 acquires vehicle speed information of the vehicle detected by the vehicle speed sensor of the sensor 11, the attitude angle and yaw rate of the vehicle detected by the gyro sensor, image information of the driver's face captured by the in-vehicle camera, and other information as driving information.

Furthermore, the control device 19 acquires the current position information of the vehicle from the vehicle position detection device 12 as driving information. The control device 19 also acquires the set destination and the route to the destination from the navigation device 15 as driving information. The control device 19 also acquires position information such as curved roads and the magnitude of the curve (e.g., curvature or curvature radius), merging points, branching points, toll booths, and positions where the number of lanes decreases as driving information from the map database 13. In addition, the control device 19 acquires information on the operation of the in-vehicle device 14 by the driver from the in-vehicle device 14 as driving information. The above is the driving information acquisition function realized by the control device 19.

The driving scene determination function of the control device 19 is a function that determines the driving scene in which the host vehicle is traveling by referring to a table stored in the ROM of the control device 19. The table stored in the ROM of the control device 19 stores, for each driving scene, driving scenes suitable for, for example, lane changing or overtaking, and the determination conditions for such scenes. The control device 19 refers to the table stored in the ROM to determine whether the driving scene in which the host vehicle is traveling is suitable for, for example, lane changing or overtaking.

For example, the following four conditions are set as conditions for determining a "scene of catching up with a preceding vehicle": "there is a preceding vehicle ahead," "the speed of the preceding vehicle is less than the set speed of the vehicle itself," "the preceding vehicle is reached within a specified time," and "the direction of the lane change does not satisfy a lane change prohibition condition." In this case, the control device 19 determines whether the vehicle itself satisfies the above conditions based on, for example, the detection results of the forward camera and forward radar included in the sensor 11, the vehicle speed of the vehicle itself detected by the vehicle speed sensor, and the position information of the vehicle itself from the vehicle position detection device 12. If the above conditions are met, the control device 19 determines that the vehicle itself is in a "scene of catching up with a preceding vehicle." This is the driving scene determination function realized by the control device 19.

The autonomous driving control function of the control device 19 is a function that allows the control device 19 to autonomously control the driving of the vehicle without relying on the driver's operation. The autonomous driving control function of the control device 19 includes an autonomous speed control function that autonomously controls the driving speed of the vehicle, and an autonomous steering control function that autonomously controls the steering of the vehicle. Note that autonomous control without relying on the driver's operation also includes the driver performing some operations. Furthermore, the autonomous speed control function and the autonomous steering control function may be functions independent of each other, or may be functions related to each other. The autonomous speed control function and the autonomous steering control function of this embodiment are described below.

The autonomous speed control function is a function that, when a preceding vehicle is detected, follows the preceding vehicle while controlling the distance between the vehicles to maintain a distance according to the vehicle speed, with the upper limit set by the driver, and when a preceding vehicle is not detected, drives at a constant speed at the vehicle speed set by the driver. The former is also called distance control, and the latter is called constant speed control. The autonomous speed control function may also include a function that detects the speed limit of the road being traveled from road signs using the sensor 11, or obtains the speed limit from the map information in the map database 13, and automatically sets the set vehicle speed to that speed limit.

To activate the autonomous speed control function, the driver first operates the resume/accelerate switch 172 or the set/coast switch 173 of the input device 17 shown in FIG. 2 to input the desired driving speed. For example, if the set/coast switch 173 is pressed while the vehicle is traveling at 70 km/h, the current driving speed is set as is, but if the driver's desired speed is 80 km/h, the resume/accelerate switch 172 can be pressed multiple times to increase the set speed. The "+" mark on the resume/accelerate switch 172 indicates that this is a switch that increases the set value. Conversely, if the driver's desired speed is 60 km/h, the set/coast switch 173 can be pressed multiple times to decrease the set speed. The "-" mark on the set/coast switch 173 indicates that this is a switch that decreases the set value. The driver can adjust the desired distance by operating the distance adjustment switch 175 of the input device 17 shown in FIG. 2 and selecting one of several settings, such as short distance, medium distance, or long distance.

Constant speed control, which drives the vehicle at a constant speed set by the driver, is executed when the forward radar of the sensor 11 or the like detects that there is no preceding vehicle ahead in the vehicle's lane. In constant speed control, the drive control device 18 controls the operation of the drive mechanisms, such as the engine and brakes, while feeding back vehicle speed data from the vehicle speed sensor so as to maintain the set driving speed.

The vehicle distance control, which follows the preceding vehicle while performing vehicle distance control, is executed when the forward radar of the sensor 11 detects the presence of a preceding vehicle ahead in the vehicle's lane. In vehicle distance control, the drive control device 18 controls the operation of the engine, brakes, and other drive mechanisms while feeding back the vehicle distance data detected by the forward radar so as to maintain the set vehicle distance with the set travel speed as the upper limit. If the preceding vehicle stops while traveling under vehicle distance control, the vehicle stops following the preceding vehicle. Also, if the preceding vehicle starts moving within, for example, 30 seconds after the vehicle stops, the vehicle also starts moving and starts following the preceding vehicle under vehicle distance control again. If the vehicle has been stopped for more than 30 seconds, the vehicle does not start automatically even if the preceding vehicle starts moving, and if the resume/accelerate switch 172 is pressed or the accelerator pedal is depressed after the preceding vehicle starts moving, the vehicle starts following the preceding vehicle under vehicle distance control again.

On the other hand, the autonomous steering control function is a function for controlling the operation of the steering actuator to execute steering control of the vehicle. The autonomous steering control function of this embodiment includes: (1) a lane keeping function (lane width direction maintaining function) that controls the steering to drive, for example, near the center of the lane and assists the driver in steering; (2) a lane change assist function that controls the steering when the driver operates the turn signal lever and assists the steering operation required for lane change; (3) an overtaking assist function that, when a vehicle slower than the set vehicle speed is detected ahead, asks the driver through a display whether to perform an overtaking operation, and when the driver operates an acceptance switch, controls the steering and assists the overtaking operation; and (4) a route driving assist function that, when the driver has set a destination in a navigation device or the like, asks the driver through a display whether to perform a lane change when the lane change point required for driving according to the route is reached, and controls the steering and assists the lane change when the driver operates an acceptance switch. When autonomous steering control is executed, autonomous speed control is also executed at the same time, but speed control may be executed by the driver's accelerator and brake operation.

Here, the lane change assist function of the autonomous steering control function will be described. Note that autonomous speed control is also executed simultaneously with lane change assist. FIG. 3 is a plan view showing an example of lane change control (lane change assist function) executed by the control device 19 of this embodiment. As shown in FIG. 3, when the driver operates the turn signal lever of the vehicle V1, the control device 19 turns on the turn signal, and starts the lane change operation LCP (Lane Change Process, a series of processes for autonomous lane change) when a preset lane change start condition is met. The control device 19 determines whether the lane change start condition is met based on various driving information acquired by the sensor 11. The lane change start conditions are not particularly limited, but examples include the following: (1) the lane is in lane keeping mode; (2) the driver is holding the steering wheel; (3) the vehicle is traveling at a speed of 60 km/h or more; (4) there is a lane in the direction of the lane change; (5) there is space in the lane to which the lane is to be changed so that the lane can be changed; (6) the lane marker type indicates that the lane change is possible; (7) the curvature radius of the road is 250 m or more; and (8) the driver has operated the turn signal lever within one second. Note that when the control device 19 determines that the lane change start conditions are met by the lane change assistance function, even without a driver's instruction, it may suggest to the driver to change lanes by notifying the driver through the presentation device 16.

When the lane change start condition is satisfied, the control device 19 starts the lane change operation LCP. As shown in FIG. 3, the lane change operation LCP in this embodiment includes a lateral movement in which the vehicle V1 moves toward the adjacent lane L2 within the lane L1, and a lane change maneuver LCM (Lane Change Manipulation) in which the vehicle V1 moves from the lane L1 to the adjacent lane L2 across a lane marker. While the lane change operation LCP is being performed, the control device 19 presents information indicating that the lane change is being performed by autonomous control to the driver via the presentation device 16, and urges the driver to pay attention to the surroundings. When the lane change maneuver LCM is completed, the control device 19 turns off the turn signal and starts the execution of a lane keeping function in the adjacent lane L2. The lane change maneuver LCP refers to the period from when the turn signal is turned on to when it is turned off by operating the turn signal lever, and the lane change maneuver LCM refers to the period from when the vehicle V1 starts to step on the boundary line between the vehicle's lane L1 and the adjacent lane L2 to when it stops stepping on it.

Now, when executing a lane change using the lane change assistance function of the autonomous steering control function, the control device 19 must recognize the position of the own lane and the position of the adjacent lane to which the lane will be changed, as well as the curvature of the road, and then check whether or not there is driving space for the own vehicle in this adjacent lane. In this case, if three-dimensional high-precision map information is stored in the map database 13, position information of the own lane and adjacent lanes and road curvature information are included, but for roads that do not contain three-dimensional high-precision map information, it is necessary to capture an image of the actual road using the front camera, side camera, and rear camera of the sensor 11, and recognize the positions of the own lane and adjacent lanes and the curvature of the road.

Figure 4 is a plan view showing an example of the installation of the front camera 111, the side camera 112, and the rear camera 113 included in the sensor 11 of Figure 1. In the installation example shown in the figure, the front camera 111 is provided in the center of the front grill or front bumper of the vehicle V, and captures the front scanning area FA of the vehicle V. The side camera 112 is provided in the door mirror of the vehicle V, and captures the left and right side scanning areas SA of the vehicle V. The rear camera 113 is provided in the center of the trunk lid, back door, or rear bumper, and captures the rear scanning area BA of the vehicle V. Although not limited in particular, the front scanning area FA captured by the front camera 111, the front scanning area SA captured by the side camera 112, and the rear scanning area BA captured by the rear camera 113 are sector-shaped with a radius of about 10 m.

5 shows an example of autonomous lane change control using the front camera 111, side camera 112, and rear camera 113 mounted in this manner. FIG. 5(A) is a plan view showing a scene in which the host vehicle V1 and the preceding vehicle V2 are traveling in the host lane L1 and the host vehicle V1 changes lanes to the adjacent lane L2 to overtake or pass the preceding vehicle V2. In this case, the positions of the lane markers LM1 and LM2 in the host lane L1 and the positions of the lane markers LM2 and LM3 in the adjacent lane L2 to which the host vehicle V1 is to change lanes are included in the forward scanning area FA by the front camera 111 even if the attitude (yaw angle) of the host vehicle V1 changes due to the lane change, so the control device 19 can recognize the position of the host lane L1 and the position of the adjacent lane L2 to which the host vehicle V1 is to change lanes. In addition, after recognizing the positions of the host lane L1 and the adjacent lane L2, the front camera 111 can also confirm whether or not there is a driving space for the host vehicle V1 in the adjacent lane L2.

In contrast, as shown in FIG. 5(B), when the attitude (yaw angle) of the vehicle V1 increases due to a lane change, the positions of the lane markers LM1, LM2 of the vehicle's lane L1 and the lane markers LM2, LM3 of the adjacent lane L2 to which the lane is to be changed are no longer included in the forward scanning area FA of the forward camera 111, and the control device 19 cannot recognize the position of the vehicle's lane L1 or the position of the adjacent lane L2 to which the lane is to be changed. As a result, the autonomous lane change control is interrupted or stopped, and the driver is forced to switch to manual operation. This situation often occurs when the distance between the vehicle V1 and the preceding vehicle V2 is short.

In the vehicle driving control device 1 according to this embodiment, when the forward scanning area FA of the front camera 111 does not include the lane markers LM1 and LM2 of the own lane L1 and the lane markers LM2 and LM3 of the adjacent lane L2 to which the lane is to be changed, and therefore the autonomous lane change control cannot be continued, the side camera 112 is used to recognize the lane markers LM1 and LM2 of the own lane L1 and the lane markers LM2 and LM3 of the adjacent lane L2 to which the lane is to be changed. Hereinafter, an embodiment of lane change control using the front camera 111 and the side camera 112 will be described. FIG. 6 is a block diagram showing an example of the lane change control unit 190 included in the control device 19, and FIGS. 7(A) and (B) are plan views showing an example of lane change control using the front camera 111 and the side camera 112, respectively.

As shown in FIG. 6, the lane change control unit 190 of this embodiment includes a lane change target trajectory generator 191, a forward lane marker estimator 192, a first following command value generator 193, a road curvature estimator 194, a second following command value generator 195, and a command value switcher 196. Signals or information are read into the lane change control unit 190 from the forward camera 111 as a forward lane marker detector, the side camera 112 (and/or the rear camera 113) as a side lane marker detector, and the sensor 11 as a vehicle state detector, and the final command value is output to the drive control device 18. Each part constituting the lane change control unit 190 is represented for convenience, and is actually realized by a program stored in ROM.

The lane change target trajectory generating unit 191 generates a target trajectory of lane change by using a lane change start signal as a trigger. When the lane change is autonomously performed by the above-mentioned driving scene determination function or when a lane change is instructed by the driver, a lane change start signal is input to the lane change target trajectory generating unit 191. FIG. 7 is a diagram showing an example of a generation process executed by the lane change target trajectory generating unit 191, in which the upper diagram is a plan view showing a scene in which the vehicle V changes lanes from the start position of the lane L1 to the end position of the lane L2, and the lower diagram is a graph showing the target lateral position _Yref and the target attitude angle _θref in the scene shown in the upper diagram. The attitude angle θ is a yaw angle with respect to the traveling direction of the vehicle V.

The lane change target trajectory generating unit 191 stores in advance the distance from the reference start position to the end position and the reference lateral position at this distance, and generates a lane change target trajectory based on these reference distances and reference lateral positions. For example, for the start position to the end position set according to the traveling speed, a transition curve that smoothly connects these start positions and end positions, such as a trigonometric function, a polynomial function, a clothoid curve, or a Bezier curve, is generated, as shown in the distance-target lateral position _{Yref graph} in the following figure. In addition, the target attitude angle θref for these start positions to end positions can be obtained by differentiating the target lateral position Yref in the distance-target lateral position Yref _graph by distance, as shown in the distance-target lateral position _θref graph in the _following figure. The lane change target trajectory generating unit 191 outputs the generated target lateral position _Yref and target attitude angle _θref for the start position to end position of the lane change to the first following command value generating unit 193.

The forward lane marker estimation unit 192 extracts forward lane markers from the image of the forward scanning area FA captured by the forward camera 111, which is the forward lane marker detection unit, and the image of the side scanning area SA captured by the side camera 112 (and/or rear camera 113), which is the side lane marker detection unit, and recognizes the lane markers of the lane in which the vehicle is currently traveling and the lane markers of the adjacent lane to which the vehicle will change lanes. Figure 8 (A) is a plan view showing an example of lane change control using the forward camera 111 and the side camera 112. Since the vehicle V1 can capture lane markers LM1, LM2 of the lane L1 in which the vehicle is currently traveling and lane markers LM2, LM3 of the adjacent lane L2 in the forward scanning area FA of the forward camera 111 and the side scanning area SA of the side camera 112, the forward lane marker estimation unit 192 recognizes the lane markers LM1, LM2, L3, calculates the road curvature ρ from the forward lane marker information (i.e., lateral position Y, attitude angle θ) of the recognized forward lane markers LM1, LM2, L3, and outputs this lane marker information Y, θ and the road curvature ρ to the first following command value generation unit 193.

The side camera 112 (and/or rear camera 113), which is the lateral lane marker detection unit, recognizes the lane markers of the lane in which the vehicle is currently traveling and the lane markers of the adjacent lane to which the vehicle is to change lanes from the captured image of the lateral scanning area SA. In FIG. 8(A), the vehicle V1 can capture the lane markers LM1 and LM2 of the lane L1 in which the vehicle is currently traveling and the lane markers LM2 and LM3 of the adjacent lane L2 in the lateral scanning area SA of the lateral camera 112. The resulting lateral lane marker information (i.e., the lateral position Y and the attitude angle θ) of the lateral lane markers LM1, LM2, and LM3 is output to the second following command value generation unit 195 and the road curvature estimation unit 194. However, the side lane marker information is only the lane markers LM1, LM2, and LM3 detected in the side scanning area SA of the vehicle V1, and not the lane markers detected in the forward area of the adjacent lane L2 into which the vehicle V1 is about to change lanes, so the curvature of the road cannot be detected directly from the captured image.

Therefore, the road curvature estimation unit 194 accumulates side lane marker information of lane markers LM1, LM2, and LM3 detected in the side scanning area SA of the vehicle V1 by the side camera 112 over time, calculates the road curvature ρ from the lateral position Y and attitude angle θ of the accumulated side lane marker information and the vehicle speed and yaw rate of the vehicle V1 detected by the sensor 11, which is the vehicle state detection unit, and outputs this to the first following command value generation unit 193. Figure 9 is a diagram showing an example of the estimation process in the road curvature estimation unit 194, and lane marker information located behind the vehicle V (lateral position Y and attitude angle θ, shown by white circles in Figure 9) corresponds to the accumulated side lane marker information.

The road curvature estimation unit 194 accumulates side lane marker information, which is a past detection result, by dead reckoning using odometry based on the vehicle speed and yaw rate of the vehicle V. Then, (1) using the accumulated most recent lateral position Y information, function approximation to a polynomial function or the like is performed by regression analysis such as the least squares method, and the road curvature is estimated from this. Alternatively or in addition, (2) using the accumulated most recent attitude angle θ information, an average value of the attitude angle change amount with respect to distance may be calculated, and the road curvature may be estimated from this. Furthermore, instead or in addition, (3) from the vehicle speed and yaw rate included in the driving state of the host vehicle V1 detected by the sensor 11, the curvature of the driving trajectory T of the vehicle V shown in FIG. 9 may be estimated, and the road curvature may be estimated from this. The method of estimating the curvature of the road from the curvature of the travel trajectory of the vehicle V (3) above may be used only when the function approximation error by the regression analysis (1) above is greater than a predetermined threshold, or when the variance of the average value of the relative angle change amount (2) above is greater than a predetermined threshold.

The first following command value generator 193 calculates a first control command value for lane change to be actually output to the drive control device 18, from the target lateral position Y _ref and target attitude angle θ _ref generated by the lane change target trajectory generator 191, and the lateral position Y _sens , attitude angle θ _sens , and road curvature ρ _road estimated by the front lane marker estimation unit 192. Fig. 10 is a diagram showing an example of the generation process executed by the first following command value generator 193 and the second following command value generator 195, where the upper diagram is a plan view showing a scene in which the vehicle V changes lanes from the start position of lane L1 to the end position of lane L2, and the lower diagram is a circuit diagram showing an example of a control circuit that compensates for the lateral position Y, attitude angle θ, and road curvature ρ in the scene shown in the upper diagram.

In the control circuit diagram shown in the lower diagram of Fig. 10, a lateral position compensation unit 197 calculates a difference ΔY between a target lateral position _Yref generated by the lane change target trajectory generation unit 191 and a lateral position _Ysens estimated by the front lane marker estimation unit 192, and outputs a control command value for a lateral position that brings this difference ΔY closer to zero by performing feedback control. An attitude angle compensation unit 198 calculates a difference Δθ between a target attitude angle _θref generated by the lane change target trajectory generation unit 191 and an attitude angle _θsens estimated by the front lane marker estimation unit 192, and outputs a control command value for an attitude angle that brings this difference Δθ closer to zero by performing feedback control. A road curvature compensation unit 199 adds a road curvature _ρroad estimated by the front lane marker estimation unit 192 to the control command value. As a result, the first following command value generation unit 193 outputs to the drive control device 18 a first control command value for following the target trajectory, which is obtained by adding the road curvature ρ _road estimated by the front lane marker estimation unit 192 to the target lateral position Y _ref and target attitude angle θ _ref generated by the lane change target trajectory generation unit 191.

In addition, the road curvature ρ _road estimated by the forward lane marker estimation unit 192 is updated successively over time when forward lane marker information can be detected by the forward camera 111. However, when the forward lane marker information goes from a detectable state to an undetectable state, it is more preferable to retain the last estimated road curvature ρ _road and use it to generate the first control command value of the first following command value generation unit 193 until the forward lane marker information becomes detectable again.

In response to this, a second following command value generator 195 calculates a second control command value for lane change to be actually output to the drive control device 18, based on the target lateral position _Yref and target attitude angle _θref generated by the lane change target trajectory generator 191, the lateral position _Ysens and attitude angle _θsens detected by the side camera 112 (and/or rear camera 113) which is a lateral lane marker detector, and the road curvature _ρroad estimated by the road curvature estimator 194. That is, using the control circuit diagram shown in the lower diagram of Fig. 10 like the above-mentioned first following command value generator 193, a lateral position compensation unit 197 calculates a difference ΔY between the target lateral position _Yref generated by the lane change target trajectory generator 191 and the lateral position _Ysens detected by the side camera 112, and outputs a lateral position control command value that brings this difference ΔY closer to zero by feedback control. The attitude angle compensation unit 198 calculates the difference Δθ between the target attitude angle θ _ref generated by the lane change target trajectory generation unit 191 and the attitude angle θ _sens detected by the side camera 112, and outputs a control command value for the attitude angle that brings this difference Δθ closer to zero by feedback control. The road curvature compensation unit 199 adds the road curvature ρ _road estimated by the road curvature estimation unit 194 to the control command value. As a result, the second following command value generation unit 195 outputs to the drive control device 18 a second control command value for following the target trajectory, which is obtained by adding the road curvature ρ _road estimated by the road curvature estimation unit 194 to the target lateral position Y _ref and target attitude angle θ _ref generated by the lane change target trajectory generation unit 191.

The command value switching unit 196 selectively switches between the first control command value generated by the first following command value generating unit 193 and the second control command value generated by the second following command value generating unit 195, and outputs one of them to the drive control device 18. The control command value output to the drive control device 18 may be either the first control command value or the second control command value, but preferably, when the forward lane marker information can be detected, that is, when the forward lane marker's lateral position, attitude angle, and road curvature can be recognized by the forward camera 111, the command value switching unit 196 outputs the first control command value of the first following command value generating unit 193 to the drive control device 18. On the other hand, when the forward lane marker information cannot be detected, that is, when the forward lane marker's lateral position, attitude angle, and road curvature cannot be recognized by the forward camera 111, the command value switching unit 196 outputs the second control command value of the second following command value generating unit 195 to the drive control device 18.

Although not particularly limited, when the command value switching unit 196 switches between the control command value of the first following command value generating unit 193 and the control command value of the second following command value generating unit 195, it is preferable that the command value switching unit 196 performs low-pass filter processing on the control command value or executes processing to suppress the amount of change in the control command value over time.

<Lane change control processing>
Next, the lane change control process according to this embodiment will be described with reference to Fig. 11. Fig. 11 is a flowchart showing an example of the lane change control process executed by the control device 19 of this embodiment. The driving control process described below is executed by the control device 19 at a predetermined time interval. In addition, in the following, it is assumed that the autonomous driving control function of the control device 19 executes autonomous speed control and autonomous steering control, and performs lane keep control to control the driving position of the host vehicle in the width direction so that the host vehicle drives within the lane at a speed set by the driver.

In step S1 of FIG. 11, the control device 19 determines whether or not a lane change control start signal has been input. The control device 19 repeats step S1 until a lane change control start signal has been input. On the other hand, if a lane change control start signal has been input, the control device 19 proceeds to step S2.

When a lane change control start signal is input, in step S2, the control device 19 judges whether the lane markers of the lane currently being traveled and the adjacent lane to which the lane is to be changed can be detected by the front camera 111, which is the front lane marker detection unit. For example, in the state shown in FIG. 8(A), the front camera 111 detects lane markers LM1, LM2, and LM3 of lanes L1 and L2 in the forward scanning area FA, so it is judged that the front lane marker information can be detected. In contrast, in the state shown in FIG. 8(B) where the attitude angle of the host vehicle V1 has increased, the front camera 111 does not detect lane markers LM1 and LM2 of lanes L1 and L2 in the forward scanning area FA, so it is judged that the front lane marker information cannot be detected. If it is judged that the front lane marker information can be detected, the process proceeds to step S3, and if it is judged that the front lane marker information cannot be detected, the process proceeds to step S6.

If it is determined that forward lane marker information can be detected, in step S3, the first following command value generator 193 generates a first control command value, and in the following step S4, lane change control is executed based on the first control command value.

On the other hand, if it is determined that the front lane marker information cannot be detected, as in the state shown in FIG. 8(B), in step S6, it is determined whether the lane markers of the lane in which the vehicle is traveling and the adjacent lane to which the vehicle is changing lanes can be detected by the side camera 112 (and/or the rear camera 113). In the state shown in FIG. 8(B), the lane markers LM1 and LM2 of the lanes L1 and L2 are not included in the forward scanning area FA of the front camera 111, but the lane markers LM1, LM2, and LM3 of the lanes L1 and L2 are included in the side scanning area SA of the side camera 112, so it is determined that the side lane marker information can be detected. Then, in step S7, the second following command value generator 195 generates a second control command value, and in the following step S4, lane change control is executed based on the second control command value. Note that if it is determined in step S6 that the side lane marker information cannot be detected, the lane change control is terminated.

In step S5, it is determined whether the lane change is complete, and if not, the process returns to step S2 and repeats the subsequent steps.

As described above, according to the vehicle driving control method and driving control device 1 of this embodiment, the road shape on which the vehicle is currently traveling, specifically the road curvature ρ, is estimated based on lateral lane marker information (lateral position Y and attitude angle θ) detected on the side of the vehicle V1, and a control command value for autonomous lane change control is generated based on this estimated road shape, a target trajectory generated by a command to start autonomous lane change control, and the detected driving state of the vehicle. This makes it possible to recognize lane markers after a lane change when changing lanes through autonomous lane change control. As a result, autonomous lane change control can be continued even if forward lane marker information cannot be detected.

In addition, according to the vehicle driving control method and driving control device 1 of this embodiment, the shape of the road on which the vehicle is currently traveling is estimated based on forward lane marker information detected in front of the vehicle V1, and autonomous lane change control is performed by selectively using a first control command value based on the road shape estimated based on the forward lane marker information and a second control command value based on the road shape estimated based on the side lane marker information. This makes it possible to expand the range of lane markers that can be detected around the vehicle V1.

In addition, according to the vehicle driving control method and driving control device 1 of this embodiment, when forward lane marker information can be detected, autonomous lane change control is executed using a first control command value based on the forward lane marker information, and when forward lane marker information cannot be detected, autonomous lane change control is executed using a second control command value based on side lane marker information, so that autonomous lane change control can be continuously executed even when forward lane marker information cannot be detected.

In addition, according to the vehicle driving control method and driving control device 1 of this embodiment, when switching between a first control command value based on forward lane marker information and a second control command value based on side lane marker information, low-pass filtering of the control command value or processing to suppress the amount of change in the control command value over time is performed, so that it is possible to suppress abrupt fluctuations in the control command value when switching.

In addition, according to the vehicle cruise control method and cruise control device 1 of this embodiment, the road shape estimated based on the forward lane marker information is updated successively over time when the forward lane marker information is detectable, and when the forward lane marker information changes from detectable to undetectable, the last estimated road shape is held and used to generate the first control command value until it becomes detectable. This makes it possible to utilize the first control command value using the forward lane marker information, which has a high reliability for estimating the road shape, as much as possible.

In addition, according to the vehicle driving control method and driving control device 1 of this embodiment, the curvature of the road is estimated by performing a regression analysis of the position information of the accumulated side lane marker information with a predetermined function, or the curvature of the road is estimated by calculating the average value of the relative angle change per unit length from the relative angle information of the accumulated side lane marker information, so that the curvature of the road can be estimated with high accuracy.

In addition, according to the vehicle driving control method and driving control device 1 of this embodiment, if the function near-time error by regression analysis is greater than a predetermined threshold value, or the variance of the average value of the relative angle change amount is greater than a predetermined threshold value, the curvature of the vehicle's driving trajectory is estimated from the vehicle speed and yaw rate included in the detected driving state of the vehicle, and this estimated curvature of the vehicle's driving trajectory is estimated as the curvature of the road, so that the curvature of the road can be estimated as accurately as possible.

In addition, according to the vehicle driving control method and driving control device 1 of this embodiment, the target trajectory when executing autonomous lane change control is generated so as to smoothly connect the position and attitude at which the host vehicle starts changing lanes and the position and attitude at which the host vehicle ends changing lanes, and the target values for the lateral position and attitude angle when executing autonomous lane change control are generated from the generated target trajectory, so that lane changes can be made along a smooth driving trajectory that provides a comfortable ride.

In addition, according to the vehicle driving control method and driving control device 1 of this embodiment, when executing the autonomous lane change control from the current lane to the target lane, a lateral position compensation process is executed to reduce the deviation between the target value of the lateral position and the actual lateral position, an attitude angle compensation process is executed to reduce the deviation between the target value of the attitude angle and the actual attitude angle, and an estimated road shape is added, so that lane changes can be performed with accurate control.

REFERENCE SIGNS LIST 1: Driving control device 11: Sensor 12: Vehicle position detection device 13: Map database 14: In-vehicle equipment 15: Navigation device 16: Presentation device 17: Input device 18: Drive control device 19: Control device V1: Vehicle V2: Leading vehicle L1: Lane currently being driven L2: Adjacent lane

Claims (11)

A vehicle driving control method for performing autonomous lane change control from a current lane to a target lane,
Detect the driving state of the vehicle,
estimating a shape of a road on which the vehicle is currently traveling based on side lane marker information detected on the sides of the vehicle;
generating a target trajectory for performing the autonomous lane change control based on a start command of the autonomous lane change control;
A vehicle driving control method for generating a control command value for the autonomous lane change control based on the detected driving state of the host vehicle, the estimated road shape, and the generated target trajectory,
A vehicle driving control method that selectively uses a first control command value based on a road shape estimated based on forward lane marker information and a second control command value based on a road shape estimated based on side lane marker information to perform the autonomous lane change control. The vehicle driving control method according to claim 1, wherein the lateral lane marker information is information about lane markers that divide lanes of a road, and includes position information of the lane markers and relative angle information of the lane markers with respect to the vehicle. When the forward lane marker information is detectable, the autonomous lane change control is executed using the first control command value;
3. The vehicle driving control method according to claim 1, wherein when the forward lane marker information cannot be detected, the autonomous lane change control is executed using the second control command value. 4. The vehicle driving control method according to claim 1, wherein, when switching between the first control command value and the second control command value, a low-pass filter process of the control command value or a process of suppressing a time-dependent change amount of the control command value is executed. The road shape estimated based on the forward lane marker information is
When the forward lane marker information is detectable, the forward lane marker information is successively updated over time;
5. A vehicle driving control method according to claim 1, wherein, when the forward lane marker information changes from detectable to undetectable, the last estimated road shape is held and used to generate a first control command value until the forward lane marker information becomes detectable. The road shape is a road curvature,
6. The vehicle driving control method according to claim 1, further comprising the step of: estimating a road curvature by performing a regression analysis of position information of the accumulated side lane marker information with a predetermined function. A vehicle driving control method for performing autonomous lane change control from a current lane to a target lane,
Detect the driving state of the vehicle,
estimating a shape of a road on which the vehicle is currently traveling based on side lane marker information detected on the sides of the vehicle;
generating a target trajectory for performing the autonomous lane change control based on a start command of the autonomous lane change control;
A vehicle driving control method for generating a control command value for the autonomous lane change control based on the detected driving state of the host vehicle, the estimated road shape, and the generated target trajectory,
The road shape is a road curvature,
A vehicle travel control method for estimating road curvature by calculating an average value of a relative angle change amount per unit length from the relative angle information of accumulated side lane marker information. A vehicle driving control method for performing autonomous lane change control from a current lane to a target lane,
Detect the driving state of the vehicle,
estimating a shape of a road on which the vehicle is currently traveling based on side lane marker information detected on the sides of the vehicle;
generating a target trajectory for performing the autonomous lane change control based on a start command of the autonomous lane change control;
A vehicle driving control method for generating a control command value for the autonomous lane change control based on the detected driving state of the host vehicle, the estimated road shape, and the generated target trajectory,
The road shape is a road curvature,
The road curvature is estimated by performing a regression analysis of the position information of the accumulated side lane marker information with a predetermined function;
estimating a road curvature by calculating an average value of a relative angle change amount per unit length from the relative angle information of the accumulated side lane marker information;
estimating a curvature of a travel path of the host vehicle from a vehicle speed and a yaw rate included in the detected travel state of the host vehicle;
When the function approximation error by the regression analysis is larger than a predetermined threshold value, or when the variance of the average value of the relative angle change amount is larger than a predetermined threshold value, the curvature of the estimated vehicle travel trajectory is estimated as the road curvature. a target trajectory when performing autonomous lane change control is generated so as to smoothly connect a position and posture at which the host vehicle starts changing a lane and a position and posture at which the host vehicle ends changing a lane;
The vehicle driving control method according to any one of claims 1 to 8 , further comprising generating a target value of a lateral position and a target value of an attitude angle when performing autonomous lane change control from the generated target trajectory. When executing the autonomous lane change control from the current lane to the target lane,
A lateral position compensation process is executed to reduce a deviation between the target value of the lateral position and an actual lateral position.
Executing an attitude angle compensation process to reduce a deviation between the target value of the attitude angle and an actual attitude angle;
The vehicle travel control method according to claim 9, further comprising adding the estimated road shape. A vehicle cruise control device including a processor for executing autonomous lane change control from a current lane to a target lane,
The processor,
Detect the driving state of the vehicle,
estimating a shape of a road on which the vehicle is currently traveling based on side lane marker information detected on the sides of the vehicle;
generating a target trajectory for performing the autonomous lane change control based on a start command of the autonomous lane change control;
A vehicle driving control device that generates a control command value for the autonomous lane change control based on the detected driving state of the host vehicle, the estimated road shape, and the generated target trajectory,
A vehicle driving control device that selectively uses a first control command value based on a road shape estimated based on forward lane marker information and a second control command value based on a road shape estimated based on side lane marker information to perform the autonomous lane change control.

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