Driving control method and driving control device

Abstract

A processor 10 that causes a host vehicle V3 to execute autonomous driving control increases the steering amount of the host vehicle V3 when the deceleration amount input by a braking operation by a driver is high, as compared to when the deceleration amount is low, during execution of driving control of a lane change for causing the host vehicle V3 to move from a first lane, in which the host vehicle V3 travels, to a second lane.

Description

Operation control method and operation control device

[0001] The present invention relates to an autonomous driving control method and driving control device for a vehicle.

[0002] There is a known system that, when the driver applies the brakes during an autonomous lane change, aborts the lane change if the deceleration is greater than or equal to a predetermined value, and completes the lane change if the deceleration is less than the predetermined value.

[0003] JP 2016-40139 A

[0004] However, if a lane change is executed on the condition that the deceleration is less than a predetermined deceleration, there is a possibility that other vehicles traveling behind the vehicle in the lane where the lane change is to be made may approach the vehicle. On the other hand, if the possibility of a lane change is determined based on the deceleration taking into account the approach of other vehicles in the lane where the lane change is to be made, the number of situations in which the lane change can be completed will decrease.

[0005] The problem to be solved by the present invention is to complete a lane change even when a braking operation is performed during a lane change and there is another vehicle approaching the vehicle in the lane to which the lane is to be changed.

[0006] The present invention solves the above problem by increasing the steering amount of the vehicle when the deceleration amount input by the driver's braking operation during autonomous lane change is high compared to when the deceleration amount is low.

[0007] According to the present invention, even if a braking operation is performed during a lane change and there is another vehicle approaching the vehicle in the lane to which the lane is to be changed, the lane change can be completed.

[0008] Fig. 1 is a block diagram showing a hardware configuration of a driving control system; Fig. 2 is a first flowchart showing a processing procedure of driving control; Fig. 3 is a diagram showing the relationship between an input deceleration amount and a steering amount; Fig. 4 is a diagram for explaining the movement of a vehicle due to driving control; and Fig. 5 is a second flowchart showing a processing procedure of driving control.

[0009] 1 shows the hardware configuration of a driving control system 100 equipped with a driving control device 1 according to this embodiment. This driving control method is implemented using the hardware components of the driving control system 100, including a processor 10 of the driving control device 1 that controls the driving of the host vehicle. The host vehicle is the vehicle that is the target of control by the driving control device 1.

[0010] The driving control system 100 includes one or more sensors 2, a host vehicle information acquisition device 3, and an other vehicle information acquisition device 4. A plurality of sensors 2 are provided in the vehicle, forming a sensor group that works in cooperation with each other. The sensors 2 detect the presence or absence of objects, including other vehicles, around the host vehicle, the distance to the objects, and the relative speed and relative acceleration of the objects. The sensors 2 detect other vehicles traveling in front of, behind, and on the left and right sides of the host vehicle (oncoming lanes, adjacent lanes, and adjacent lanes). The sensors 2 detect other vehicles traveling in at least a first lane in which the host vehicle is traveling, a second lane adjacent to the first lane (different from the first lane), and a third lane adjacent to the second lane (an adjacent lane to the first lane). The detection information acquired by the sensors 2 is provided to the processor 10.

[0011] The sensor 2 includes one or more cameras 21 arranged on the vehicle. The single or multiple cameras 21 capture images of the vehicle's surroundings in all directions. The cameras 21 include image sensors with imaging elements such as CCDs, ultrasonic cameras, and infrared cameras. The cameras 21 include at least a front camera that captures images in front of the vehicle, a rear camera that captures images behind or on the rear sides of the vehicle, and left and right side cameras that capture images of the left and right sides of the vehicle, and the front and rear of the left and right sides. The type of camera 21 is not limited as long as it can capture images in all directions of the vehicle. A single camera 21 mounted on a base with a rotation mechanism may be used, or it may be used in combination with one or more other cameras 21. The sensor 2 includes a radar device 22 that detects (measures distance to) the presence, position, and position change of objects around the vehicle. The radar device 22 emits electromagnetic waves toward the object and measures the reflected waves to measure the distance and direction to the object. The radar device 22 includes a laser radar, a millimeter-wave radar (LRF), a light detection and ranging (LiDAR) unit, an ultrasonic radar, and a sonar. The sensor 2 includes a global positioning system (GPS) unit, a gyro sensor, a vehicle speed sensor, and the like, and detects the position of the vehicle at each timing. Each sensor 2 can also acquire information from an in-vehicle device or an external device according to its function. Each sensor 2 transmits the acquired detection information to the vehicle information acquisition device 3, the other vehicle information acquisition device 4, or the processor 10 in response to a request or command. The processor 10 may acquire the detection information directly from the camera 21 or the radar device 22, or may acquire the detection information via the vehicle information acquisition device 3 or the other vehicle information acquisition device 4.

[0012] The host vehicle information acquisition device 3 calculates the current position, attitude, speed, acceleration, behavior, and direction of travel of the host vehicle based on the detection information acquired from the sensor 2, and provides the calculated information to the processor 10. The other vehicle information acquisition device 4 calculates the position, attitude, speed, acceleration, behavior, and direction of travel of objects, including other vehicles, around the host vehicle based on the detection information acquired from the sensor 2, and provides the calculated information to the processor 10.

[0013] The driving control system 100 further includes map information 5 and lane information 51. The map information 5 and lane information 51 are stored in an on-board storage device or an external server that the processor 10 can access via the communication device 30. The map information 5 is high-precision map information that includes the lane information 51 that is referenced when performing autonomous lane change control. The lane information 51 includes identification information that identifies each of multiple lanes belonging to a road. The navigation device 6 references the map information 5 and calculates a route to a set destination. This route includes a target trajectory that identifies the lanes to travel on. The route and target trajectory calculated by the navigation device 6 are provided to the vehicle controller 200 and used for autonomous driving control.

[0014] The driving control system 100 includes a vehicle controller 200. The vehicle controller 200 includes a steering control device 210 and a drive control device 220. The vehicle controller 200 acquires command values ​​for autonomous driving control according to a driving plan formulated by the processor 10 of the driving control device 1, and controls the host vehicle to travel along a route to a destination. The route is composed of a series of target trajectories to which command values ​​are associated. The target trajectories include trajectories for lateral movement and / or lane changes to avoid approaching other vehicles. The trajectories for lateral movement are calculated based on target lateral positions that avoid approaching other vehicles in front and behind. The trajectories for lane changes are calculated based on target lateral positions set in adjacent lanes to avoid approaching other vehicles. The command values ​​for driving control are generated by the vehicle controller 200 or the processor 10. The command values ​​are vehicle control command values ​​for driving the host vehicle along the target trajectory. The command values ​​include a set speed for driving the vehicle, and the vehicle controller 200 drives the host vehicle according to the set speed. The set speed may be set automatically according to predetermined standards based on information detected by sensors 2, such as the distance to the preceding vehicle and the relative speed and acceleration relative to the preceding vehicle, subject to legal regulations, or may be set by the driver via the input / output device 20. The vehicle controller 200 inputs longitudinal and lateral forces that control the vehicle's driving position based on command values. Based on these inputs, the vehicle body behavior and wheel behavior are controlled so that the vehicle autonomously travels along a route to the destination. Based on these controls, at least one of the drive actuators and brake actuators of the vehicle body drive mechanism controlled by the drive control device 220 and the steering actuator of the steering control device 210, which is activated as needed, operate autonomously, thereby executing autonomous driving control that causes the vehicle to autonomously travel along a target trajectory. The vehicle controller 200 suspends autonomous driving in response to a predetermined driver intervention, even during autonomous driving, and transfers driving control to the driver. The vehicle controller 200 drives in accordance with command values ​​based on the driver's manual operation input via the input / output device 20.

[0015] The driving control device 1, which performs overall control of the driving control system 100, includes a processor 10. The processor 10 controls autonomous driving of the vehicle. As one form of autonomous driving control, the processor 10 autonomously executes lane changes of the vehicle. The processor 10 includes a ROM (Read Only Memory) 12 that stores programs for controlling autonomous driving, including autonomous lane changes, a CPU (Central Processing Unit) 11 that executes the programs stored in the ROM 12, and a RAM (Random Access Memory) 13 that functions as an accessible storage device. The processor 10 implements this driving control method using each piece of hardware in the driving control system 100.

[0016] Processor 10 executes each function by cooperating with software for realizing a driving control function that causes the vehicle to travel along a route to the destination and, as one aspect of that function, a lane control function that causes the vehicle to move from the first lane to the second lane while traveling, and each hardware shown in Figure 1.

[0017] Processor 10 executes lane change control to move the host vehicle from the first lane in which the host vehicle is traveling to the second lane. The second lane is a lane different from the first lane and adjacent to the first lane. The lane change function of processor 10 refers to lane information 51 based on the current position of the host vehicle, identifies the first lane in which the host vehicle is traveling, and identifies the second lane adjacent to the first lane in which the host vehicle is traveling. The lane change function determines whether there is an area in which the host vehicle can travel after moving to the second lane, detects the positional relationship between a front vehicle in front of the host vehicle and a rear vehicle in the rear lane, determines the inter-vehicle distance and relative speed between the host vehicle and the rear vehicle, and controls the longitudinal and lateral behavior of the host vehicle so that the inter-vehicle distance or time to collision (TTC) with the rear vehicle in the second lane does not fall below a predetermined threshold. The lane change function controls the steering of the vehicle, moving the vehicle from the first lane to a target lateral position in the second lane according to the target trajectory of the driving plan formulated at the time of lane change execution (including at the start and after the start). Once the lateral movement is complete, the vehicle's orientation is aligned with the direction of travel in the second lane, completing the lane change. Depending on the lane width of each road, the amount of lateral movement of the vehicle's reference position along the road width from the start to the completion of the lane change corresponds to the width of the first or second lane along which the vehicle is traveling. The reference position of the vehicle is the vehicle's width center or center of gravity. If the driver feels that the speed during autonomous lane change execution is high or recognizes a change in the driving environment, the driver may perform a braking operation, such as depressing the brake pedal (I / O device 20). The processor 10 calculates the deceleration amount based on the amount of operation, such as the amount of brake pedal depression, and calculates the steering amount corresponding to the calculated deceleration amount. The processor 10 controls the steering amount according to the calculated deceleration amount. The steering amount may be calculated as a steering angle. Specifically, when the deceleration rate input by the driver's braking operation is high, the processor 10 calculates a larger steering amount for the host vehicle than when the deceleration rate is low. A driving plan with the changed steering amount is created after the lane change is initiated. The calculated steering amount is sent to the vehicle controller 200 and used for autonomous lane change control. By relatively increasing the steering amount when the deceleration rate is high, the host vehicle can be moved according to the target lateral position change amount in the driving plan created at the start of the lane change.This allows the planned lane change to be completed even if a braking operation is input during a lane change and another vehicle in the second lane behind approaches the vehicle.

[0018] Based on the flowchart in FIG. 2, the autonomous driving control process when the driver inputs a deceleration operation during a lane change will be described. The processor 10 acquires detection information from the sensor 2 (S1). The detection information includes detection information based on image capture information from the camera 21 and detection information based on observation information from the radar device 22. The processor 10 acquires host vehicle information, including the current position and speed of the host vehicle, from the host vehicle information acquisition device 3 (S2). The processor 10 acquires the deceleration amount input by the driver's braking operation, the route planned for the host vehicle to move from the first lane to the second lane, and driving command values ​​associated with each position constituting the route. The driving command values ​​include one or more of the operation command value, drive command value, and braking command value set for the route. The processor 10 acquires lane information for the first lane in which the host vehicle is traveling and the second lane adjacent to the first lane by referring to the detection information from the sensor 2 or the lane information 51 in the map information 5. The first lane and the second lane are included in the route to the destination. The lane positions of the first and second lanes are obtained from the detection information of the sensor 2.

[0019] The processor 10 acquires information about other vehicles traveling around the host vehicle, such as the presence or absence, position (distance), speed, and acceleration, from the other vehicle information acquisition device 4 (S3). When changing lanes, the processor 10 acquires information about other vehicles traveling ahead and behind the host vehicle in the second lane, i.e., the front vehicle diagonally ahead and the rear vehicle diagonally behind the host vehicle traveling in the first lane.

[0020] The processor 10 determines whether the lane change conditions are met as necessary (S4). The lane change condition is that the drivable area of ​​the host vehicle can be calculated while maintaining a predetermined inter-vehicle distance or a predetermined TTC with respect to another vehicle ahead or behind in the second lane. If the lane change conditions are met, lane change control is initiated to move the host vehicle toward the second lane (S5). The lane change control includes a process for calculating a target trajectory for the planned lane change and a process for generating vehicle command values ​​(steering command value, braking command value, and drive command value) for each point on the target trajectory. At this point, the processor 10 formulates a reference lane change plan. This reference lane change plan does not take into account deceleration due to braking input by the driver during a lane change. If a braking input is input after the lane change has started, the processor 10 formulates a new target lane change plan to follow, based on or independently of the reference lane change plan. When a lane change is initiated, the vehicle moves laterally from the center of lane 1 to approach lane 2. If the lane change conditions are not met, the driving situation is checked repeatedly (if NO in S4, return to S1).

[0021] After the lane change is initiated (S5), the processor 10 determines whether the driver has input a braking operation during the lane change (S6). The driver can input a braking operation by, for example, depressing the brake pedal of the vehicle, even during a lane change. The processor 10 acquires a deceleration amount corresponding to the amount of braking operation input by the driver (S7). The processor 10 calculates a steering amount of the vehicle corresponding to the deceleration amount (S8). The processor 10 stores a mathematical formula defining the relationship between the deceleration amount and the steering amount, and calculates the steering amount by applying the acquired deceleration amount of the vehicle to this mathematical formula. The processor 10 also stores a relationship that associates the deceleration amount with the steering amount, and acquires the steering amount by applying the deceleration amount to this relationship. In this embodiment, the steering amount when the deceleration amount input by the driver's braking operation is high is defined as being larger than when the deceleration amount is low. The change in steering amount is achieved by an increase in the steering angle, an increase in the steering angular velocity, and an increase in the steering angular acceleration. As the steering amount increases, the rate of change or acceleration of change in the lateral position of the host vehicle increases. The mathematical formula or the corresponding relationship is defined depending on the performance of the host vehicle.

[0022] FIG. 3 shows an example of the relationship between the deceleration amount input by the driver and the steering amount. As shown by the relationship F1 (solid line) in FIG. 3, the correspondence relationship between the deceleration amount and the steering amount may be defined such that the steering amount increases as the deceleration amount input by the driver increases. The increase coefficient may be set arbitrarily depending on the vehicle performance, etc. As shown by F2 (dashed line) in the same figure, the correspondence relationship between the deceleration amount and the steering amount may be defined such that the steering amount increases stepwise as the deceleration amount input by the driver increases. The range of the deceleration amount and the increase amount of the operation amount may be set arbitrarily depending on the vehicle performance, etc. As shown by F3 (dashed line) in the same figure, the correspondence relationship between the deceleration amount and the steering amount may be defined such that the steering amount increases according to an index as the deceleration amount input by the driver increases. The increase index may be set arbitrarily depending on the vehicle performance, etc. In the curved relationship of F3, the increase magnitude of the steering amount can be adjusted depending on the range of the deceleration amount. Based on the input deceleration amount and the steering amount calculated based on the deceleration amount, processor 10 calculates a target trajectory for lane change control and command values ​​at each point on the target trajectory, and creates a driving plan including these. Processor 10 then causes vehicle controller 200 to execute the driving plan including the lane change (S9). The host vehicle moves from the first lane to the second lane with the specified steering amount (S10). Note that if the driver does not input a braking operation during the lane change (NO in S6), the lane change is executed based on the driving plan that was created at the start of the lane change and does not take into account the input of a braking operation (S9), and the host vehicle is moved to the second lane (S10).

[0023] An example of lane change control according to this embodiment is shown in FIGS. 4(a), 4(b), and 4(c). In this specification, the horizontal direction indicates the X direction in FIG. 4, which corresponds to the lane width, and the vertical direction indicates the Y direction, which corresponds to the lane extension direction. Each diagram is a schematic representation of the positional relationship between the host vehicle and the lane. The time axes in each diagram are not the same, and are not intended to accurately represent the relative speed or relative position between the host vehicle and other vehicles. FIG. 4(a) schematically illustrates the host vehicle V1 traveling in the first lane L2 and the other vehicle VX traveling in the second lane L3 when a lane change is executed. The host vehicle V1 (T1) moves along the target trajectory R1 in the lane change control. At timing T1 when the lane change is initiated, the host vehicle V1 (T1) begins lateral movement (movement along the X direction) to approach the second lane L3. At timing T2, a portion of the host vehicle V1 (T2) enters the second lane L3; at timing T3, the reference position (lateral center or center of gravity) of the host vehicle V1 (T3) enters the second lane L3; and at timing T4, the entire host vehicle V1 (T4) enters the second lane L3. Finally, the host vehicle V1 (T4) is steered so that its direction is aligned with the direction of travel of the second lane L3, and the lane change is determined to be complete. Alternatively, the lane change may be determined to be complete when the reference point (vehicle width center) of the host vehicle V1 (T1) moves from the center position L2M of the first lane L2 to the center position L3M of the second lane L3. The lateral movement (X direction in the figure) of the host vehicle V1 (T1-T4) from the start to the completion of the lane change is TX1, and the longitudinal movement (Y direction in the figure) is TY1. The distance between the vehicle V1 (T4) that has completed the lane change and the vehicle VX traveling behind it in the second lane L3 is indicated by D1.

[0024] Figure 4(b) shows a schematic diagram of the host vehicle V2 traveling in the first lane L2 and the other vehicle VX traveling in the second lane L3 when the driver inputs a braking operation during a lane change. The host vehicle V2 (T1) moves along the target trajectory R2 for lane change control. When the lane change is initiated, the host vehicle V2 (T1) begins to move laterally (in the X direction) to approach the second lane L3, passing through the positions of the host vehicle V2 (T2) and the host vehicle V2 (T3), and then to the host vehicle V2 (T4) in the second lane L3. When a braking operation is input during a lane change, movement in the Y direction is suppressed, and the inter-vehicle distance D2 between the host vehicle V2 (T4) and the other vehicle VX becomes shorter than the inter-vehicle distance D1 between the host vehicle V1 (T4) and the other vehicle VX when no braking operation is input (D1 > D2), indicating a tendency for the two vehicles to approach each other.

[0025] Figure 4(c) shows a schematic diagram of the host vehicle V3 and the other vehicle VX when the driver inputs a braking operation during a lane change and control is performed to control the steering amount according to the input deceleration amount. The host vehicle V2 changes lanes from the first lane L2 to the second lane L3, and the other vehicle VX travels in the second lane L3. The host vehicle V3 (T1) moves along the target trajectory R3 for lane change control. In this control, the driving of the host vehicle is controlled so that the steering amount is larger when the deceleration amount is high than when the deceleration amount is low. For example, when the driver presses the brake pedal hard, the lane change is executed with a larger steering amount than when the driver presses the brake pedal lightly. When the lane change is initiated, the host vehicle V3 (T1') begins to move laterally (in the X direction) toward the second lane L3, passing the positions of the host vehicle V2 (T2') and the host vehicle V2 (T3') before reaching the host vehicle V2 (T4') in the second lane L3. Note that the timings T1'-T4' in Figure 4(c) are not limited to being the same as the timings T1-T4 in Figures 4(a) and 4(b). Due to the influence of a braking operation input during a lane change, the displacement of the longitudinal position (Y-axis coordinate) of the host vehicle V3 tends to be smaller relative to the displacement of its lateral position (X-axis coordinate). However, in the control example shown in Figure 4(c), the steering amount is increased. Therefore, the time required to complete the lane change is shorter in the control example shown in Figure 4(c) than in the control example shown in Figure 4(b). In other words, as shown in Figure 4(c), in lane change control with an increased steering amount, the lateral position of the host vehicle V3 moves toward the second lane L3 at an early timing. The timing N2' when a part of the host vehicle V3 enters the second lane L3 and the timing N3' when the reference position of the host vehicle V3 enters the second lane L3 are located upstream compared to the timings N2 and N3 (shown in FIG. 4(b)) of lane change control that does not increase the steering amount. Therefore, the host vehicle V3 is moved to the second lane L3 before the other vehicle VX shown in FIG. 4(c) reaches position Y1, that is, when the other vehicle VX is at upstream position Y2. The host vehicle V3 (T4) completes the lane change before the other vehicle VX behind approaches the host vehicle V3, and therefore the inter-vehicle distance between the other vehicle VX (Y2) and the host vehicle V3 is maintained appropriately.Depending on the speed of the other vehicle VX, the lateral movement required for changing lanes can be performed in a short time, so the inter-vehicle distance D3 between the subject vehicle V3 (T4') and the other vehicle VX (Y2) shown in Figure 4(c) can be made longer than the inter-vehicle distance D2 between the subject vehicle V2 (T4) and the other vehicle VX shown in Figure 4(b) (D3 > D2).

[0026] If the vehicle completes the lane change without taking any action when a braking operation is input during a lane change, there is a high possibility that the vehicle will approach another vehicle VX following behind in the second lane L3. Furthermore, if the vehicle determines whether to change lanes at a reduced speed while avoiding approaching another vehicle VX, the number of situations in which the lane change can be completed will decrease. Furthermore, while braking operations input by the driver for purposes other than lane changes are reflected in the autonomous driving system, ignoring braking operations only when driving control for a lane change is executed can cause the driver to feel uncomfortable. In contrast, when a braking operation is input, the lane change is executed with a higher steering amount when the deceleration rate is high compared to when the deceleration rate is low. This maintains or shortens the time required to complete the lane change, i.e., the time required to move the vehicle V3 from the first lane L2 to the second lane L3. This allows the vehicle to move into the second lane so as to follow the lateral position change amount defined by the target trajectory (a target trajectory in which no braking operation is planned) planned at the start of the lane change. Since the time when the host vehicle V3 enters the second lane L3 can be advanced, the other vehicle VX behind the host vehicle V3 in the second lane L3 can notice the host vehicle V3's lane change earlier and can autonomously perform operations to maintain a safe distance. Even if a braking operation increases the likelihood of a situation in which a rear vehicle approaches the lane change destination, the host vehicle can complete the lane change by increasing the steering amount, thereby not reducing the number of situations in which a lane change is possible. Furthermore, even if a braking operation is input during a lane change, the driver's braking control is reflected in the driving, so the driver does not feel uncomfortable. Incidentally, this driving control focuses on braking operations (brake control) input by the driver during an autonomous lane change. When the host vehicle is decelerated by a braking operation, the relative speed with respect to the other vehicle behind increases, so the detection range is expanded rearward, and it becomes necessary to consider the impact on the rear vehicle traveling within the expanded detection range. Since the lane change is executed with the trajectory corrected by controlling the steering amount, the lateral movement to the second lane can be completed early and the vehicle further behind can be prevented from being affected. On the other hand, even if a driving operation (acceleration control) is performed during the lane change, the problems of the increase in relative speed with the vehicle further behind caused by the braking operation described above, the expansion of the detection area to the rear, and the need for new processing to adjust the position with the vehicle further behind do not arise.The driving control of this embodiment is effective when a braking operation is input during a lane change.

[0027] In this embodiment, the processor 10 increases the steering amount so that the target time for moving the host vehicle V1 from the first lane L2 to the second lane L3 is equal to or shorter than a predetermined reference time. This feature can also be defined as the target time being shorter than the reference time. Specifically, the processor 10 references the reference time T1 defined in a driving plan, which is created at the start of a lane change and is intended for when no braking operation is performed during the lane change. The processor 10 increases the steering amount so that the target time T3 required for the reference position of the host vehicle V3 shown in FIG. 4(c) to move a lateral movement amount TX3 from the center L2M of the first lane L2 to the center L3M of the second lane L3 is equal to or shorter than the reference time T1 required for the reference position of the host vehicle V1 (T1) shown in FIG. 4(a) to move a lateral movement amount TX1 from the center position L2M of the first lane L2 to the center position L3M of the second lane L3. The processor 10 laterally moves the host vehicle V3 according to a lateral position change rate that completes the lane change of the host vehicle V3 when the target time T3 is equal to or shorter than the reference time T1. The time T3 is shorter than the time T2 required to move the lateral movement amount TX2 when the steering amount is not controlled, as shown in FIG. 4(b). The reference time T1 is set based on a typical movement time (e.g., approximately 6 seconds) when no braking operation is performed during a lane change (see FIG. 4(a)). The target time T3 can be set to a shorter time (e.g., 4-5 seconds). The reference time T1 and the target time T3 are appropriately set in consideration of the driving environment based on one or more factors, such as the relative positions, relative speeds, and TTC between the host vehicle V3 and the other vehicles ahead and behind it traveling in the second lane L3. The processor 10 sets a target position in a drivable area between the vehicle ahead and the vehicle behind traveling on the second lane L3, where the host vehicle V3 that has changed lanes can maintain a predetermined distance or more between the vehicle ahead and the vehicle behind. The processor 10 then calculates a reference time and / or a target time based on one or more of the distance in the X direction (horizontal direction) between the current position of the host vehicle V3 and the target position, the distance in the Y direction (vertical direction), and the route from the current position to the target position. The reference time and / or the target time are periodically calculated and updated to respond to changes in the situation.From a similar perspective, the steering amount is set large so that the target lateral speed VL3 when the host vehicle V3 shown in FIG. 4(c) moves a lateral movement amount TX3 is equal to or less than the reference lateral speed VL3 when the host vehicle V1 (T1) shown in FIG. 4(a) moves a lateral movement amount TX1. This allows the target time T3 to be equal to or less than the reference time T1. By shortening the target time T3 required for the lane change compared to the reference time T1, the host vehicle completes its movement to the second lane L3 before the other vehicle VX behind approaches, thereby completing the lane change. The processor 10 drives the host vehicle V3 based on the lateral position movement plan that was planned at the start of the lane change, i.e., based on the driving plan in a situation where no braking operation is input. Therefore, even if another vehicle is traveling behind in the second lane L3, the lane change destination, the lane change can be completed without narrowing the inter-vehicle distance with the other vehicle VX. Furthermore, the target time T3 may be set depending on whether the lane change is mandatory. When a lane change is mandatory, the processor 10 relaxes the conditions for whether or not a lane change is possible (such as proximity to other vehicles) compared to when a lane change is not mandatory. In a situation where a lane change is mandatory, failing to change the lane can result in disadvantages such as not reaching the destination on time. To avoid this, it is considered to prioritize the execution of the lane change by relaxing the conditions for executing the lane change. On the other hand, when there is another opportunity to change the lane, it prioritizes a normal lane change without relaxing (changing) the conditions for executing the lane change. This relaxation measure can also be applied to the reference time T1 and target time T3 required for a lane change described above. For example, when a lane change is mandatory, the reference time T1 and target time T3 can be set shorter than when a lane change is not mandatory. Although the change in steering amount is larger, this is allowed in order to ensure that the lane change, which is the only opportunity to execute, is completed. As a specific processing, when a lane change is necessary, the target time T3 may be directly shortened, or the reference time T1 may be shortened and the target time T3 may be calculated according to the shortened reference time T1.

[0028] Here, a description will be given of lane changes that are mandatory for the host vehicle to travel along a route to the destination. For the host vehicle to travel along a route to the destination, it is necessary to move from the road it is currently traveling on to another road at a predetermined junction, and for this movement to occur, it is necessary to change lanes by the predetermined point. Mandatory lane changes are performed in a remaining area (upstream area) of a predetermined distance up to a location where road structures such as a branch, merge, exit, or entrance intersect. If a lane change fails in the remaining area, the host vehicle will not arrive at the destination by the scheduled time, which would impair the achievement of the original purpose of autonomous driving. Furthermore, there are situations in which a lane change must be performed to avoid an obstacle ahead in order for the host vehicle to travel along a route to the destination. In this specification, a lane change that is mandatory for the host vehicle to travel along a route to the destination is referred to as a first lane change. The first lane change includes a mandatory lane change defined in the field of autonomous driving technology. A second lane change other than the first lane change is an optional lane change that can be performed at a later time. The second lane change includes a discretionary lane change defined in the field of autonomous driving technology. A lane change is necessary to travel on a branching road leading to a destination, but a lane change made early due to the driver's preference or the policy of the navigation device 6 even when there is sufficient distance to the branching point is not essential and is a second lane change. A lane change to overtake another vehicle ahead in order to travel at the driver's desired speed is also a second lane change.

[0029] Although not particularly limited, the driving control of this embodiment can be executed in a predetermined scenario. Returning to FIG. 2 , after the lane change condition is satisfied (YES in S4), the processor 10 determines whether the driving environment is a predefined scenario (S20). The driving environment is determined based on the detection results of the sensor 2, the host vehicle information obtained from the host vehicle information acquisition device 3, and the other vehicle information obtained from the other vehicle information acquisition device 4. The process of S20, which is connected by a dashed line, can be skipped. As a process for determining the first control execution scenario, the processor 10 determines whether the lane change to be executed is a first lane change, which is required for the host vehicle to travel along a route to the destination, based on the host vehicle's driving environment (S20). Whether the lane change is a first lane change is determined by the following process. The processor 10 acquires a remaining area within a predetermined distance to the branch, merge, exit, or entrance position in the road structure acquired from the map information 5 or lane information 51, and the current position of the host vehicle from the host vehicle information acquisition device 3. The processor 10 compares the current position of the host vehicle with the remaining area, and if the host vehicle is in the remaining area, determines that the host vehicle is in a situation where it should perform a first lane change. This determination may be made by the navigation device 6. If it is determined that the lane change is a first lane change (YES in S20), the process proceeds to S6, where the steering amount is controlled according to the deceleration amount (S6-S10). If not (NO in S20), a normal lane change is performed without controlling the steering amount according to the deceleration amount (S9), and the host vehicle travels in the second lane (S10). For a required first lane change, lane change control must be completed. Driving control with increased steering amount allows the required first lane change to be completed. As a result, autonomous driving can be achieved, allowing the host vehicle to arrive at its destination in accordance with the driver's wishes.

[0030] As a determination process for the second control execution scene, processor 10 determines whether a rear vehicle approaching the host vehicle is detected in the second lane based on the driving environment of the host vehicle (S20). The host vehicle's position and speed are obtained from host vehicle information acquisition device 3, and the rear vehicle's position and speed are obtained from sensor 2 or other vehicle information acquisition device 4, and the degree of proximity between the host vehicle and the rear vehicle is determined. If a rear vehicle approaching the host vehicle is detected in the second lane (YES in S20), the process proceeds to S6, where the steering amount is controlled according to the deceleration amount (S6-S10). If not (NO in S20), a normal lane change is performed without controlling the steering amount according to the deceleration amount (S9), and the host vehicle travels in the second lane (S10). Even if a braking operation is input to the host vehicle and a rear vehicle approaching the host vehicle is detected in the second lane, the lane change can be completed by driving control with increased steering amount.

[0031] In the determination process for the third control execution scenario, processor 10 determines whether a following vehicle has been detected behind the host vehicle in the first lane (S20) based on the driving environment of the host vehicle. The host vehicle's position and speed are obtained from host vehicle information acquisition device 3, and the position and speed of the following vehicle in the first lane are obtained from sensor 2 or other vehicle information acquisition device 4, and the degree of proximity between the host vehicle and the following vehicle is determined. If a following vehicle approaching the host vehicle is detected in the first lane (YES in S20), the process proceeds to S6, where the steering amount is controlled according to the deceleration amount (S6-S10). If not (NO in S20), a normal lane change is performed without controlling the steering amount according to the deceleration amount (S9), and the host vehicle travels in the second lane (S10). Even if a braking operation is input to the host vehicle and a following vehicle approaching the host vehicle is detected behind the first lane, the lane change can be completed by driving control with increased steering amount.

[0032] Although not particularly limited, if a vehicle approaching the host vehicle from behind is detected in the second lane (YES in S21), and the deceleration amount required by the braking operation (S7) is equal to or greater than a preset tolerance (YES in S22), the autonomous lane change of this embodiment is canceled (S23), and the host vehicle is allowed to travel in the first lane (S24). If a vehicle approaching the host vehicle from behind is not detected in the second lane (NO in S21), there is no problem in executing a lane change even if the deceleration amount is greater than the tolerance. Therefore, the process proceeds to S8, and the lane change is executed based on a steering amount corresponding to the deceleration amount. Even if the deceleration amount required by the braking operation (S7) is equal to or greater than a preset tolerance (NO in S22), the process proceeds to S8, and the lane change is executed based on a steering amount corresponding to the deceleration amount. If the deceleration amount input by the driver is equal to or greater than the tolerance, it can be assumed that the driver actively decided to cancel the lane change. Since it is possible that another vehicle may enter the second lane from outside the detection range of sensor 2, this process prioritizes the driver's judgment. Also, if the driver is pressing the brake pedal to apply the brakes, it can be determined that the driver is ready to immediately take over manual driving, so there is no problem in canceling the autonomous lane change. This makes it possible to execute driving control according to the driver's intentions and actual driving conditions while also attempting to complete the autonomous lane change.

[0033] In principle, the processor 10 performs deceleration control by applying a braking force corresponding to the deceleration amount based on the braking operation input by the driver to the host vehicle. However, if the input deceleration amount is large, the host vehicle V3 may approach the vehicle behind it in the second lane L3. This embodiment proposes a response process for when the input deceleration amount is large. Note that if the input deceleration amount is equal to or greater than the allowable value, the lane change is canceled as described above. The "predetermined value" for the deceleration amount in this example, which will be described later, is less than the allowable value. The processor 10 sets a predetermined value that functions as an upper limit for the deceleration amount input by the driver's braking operation and limits the braking force applied to the host vehicle. If the deceleration amount input by the driver's braking operation exceeds the predetermined value, the excess amount is limited, and the host vehicle is controlled at the predetermined deceleration amount. This subroutine will be described based on the flowchart shown in Figure 5. Figure 5 uses the flowchart of Figure 2 and adds steps S31-S35. The overlapping displays of S1-S6 and S8-S10 in FIG. 2 are used here and omitted in FIG. 5 to avoid redundancy. The processing of S31-S35 in FIG. 5 can be executed in combination with the processing of S21-S24 and / or S20 in FIG. 2. Regarding this processing, the descriptions of S1-S10, S20, and S21-S24 in FIG. 2 are appropriately referenced. In S7 following YES in S6 in FIG. 2, the processor 10 acquires the deceleration amount input by the driver's braking operation (S7). The processor 10 acquires or calculates a predetermined value (S31). The predetermined value may be preset (e.g., 0.2G-0.3G) depending on vehicle performance, or may be determined each time taking into account the distance between the host vehicle V3 and another vehicle in the second lane behind the host vehicle V3. The predetermined value may also be calculated depending on the situation, as described below. If the deceleration input by the driver's braking operation is equal to or greater than a predetermined value (YES in S32), the process proceeds to S33. If not (NO in S32), the process follows the processing from S8 onward in FIG. 2 to execute an autonomous lane change with controlled steering amount (S8-S10). In S33, the processor 10 calculates the excess deceleration amount relative to the predetermined value (S33). The excess deceleration amount is the difference between the input deceleration amount and the predetermined value. The processor 10 limits (cancels) the braking force corresponding to this excess deceleration amount (S34).The input deceleration amount is corrected to a predetermined value, and the corrected deceleration amount is output to vehicle controller 200 (S35). Vehicle controller 200 executes an autonomous lane change with controlled steering amount, following the process from S8 onward in FIG. 2 based on the corrected (limited) deceleration amount (S8-S10). A sudden decrease in the speed of the host vehicle may induce sudden braking by a following vehicle or the host vehicle and the following vehicle may become close to each other. This process limits the braking force corresponding to the excessive deceleration amount. Therefore, even if a deceleration amount that is too large to follow the planned change in lateral position in lane change control is input, the host vehicle can execute the lane change as planned while avoiding sudden braking or a sudden close encounter with the following vehicle.

[0034] To control the braking force limitation, the processor 10 calculates the predetermined value using a method appropriate to the driving environment. A predefined predetermined value can be used in the calculation of the predetermined value. The processor 10 calculates the predetermined value according to the result of determining whether the lane change to be executed is a first lane change. The first lane change is a lane change that must be executed in order for the host vehicle to travel along a route to the destination. The processor 10 calculates a higher predetermined value when the lane change is determined to be a first lane change than when the lane change is determined to be a second lane change rather than a first lane change. In other words, the braking force to be limited when the lane change is determined to be a first lane change is smaller than the braking force to be limited when the lane change is determined to be a second lane change. Even if a high deceleration amount is input by a braking operation, the high deceleration amount is allowed to complete the first lane change. By increasing the braking force to be limited when the first lane change is executed compared to when the second lane change is executed, the first lane change, which must be executed, can be completed. As a result, autonomous driving can be completed to reach the destination according to the driver's requests.

[0035] The processor 10 calculates the predetermined value according to the vehicle speed of the host vehicle when a lane change is to be performed. The processor 10 calculates the predetermined value so that the predetermined value when the host vehicle speed is high when the driver inputs a braking operation is lower than the predetermined value when the host vehicle speed is low. In other words, the braking force limit is set higher when the host vehicle speed is high than when the host vehicle speed is low. When the host vehicle speed is high, changes in the host vehicle's behavior have a greater impact on traffic flow, including other vehicles. When a change in the host vehicle's behavior occurs while traveling at high speed, the actual positional relationship is likely to deviate significantly from the prediction. If irregular control is performed when the host vehicle speed is high, the lane change condition may not be satisfied, and the lane change may be canceled. Furthermore, when the host vehicle speed is high, the detection area of ​​the sensor 2 is expanded, and the range of influences to be considered is also expanded, so the lane change may be canceled due to a change in the situation. If a braking operation is performed when the host vehicle speed is high, there is a possibility that the host vehicle will suddenly approach another vehicle, which may result in the lane change being canceled. In this embodiment, the predetermined value is set lower when the host vehicle speed is high than when it is low, thereby increasing the braking force limit, thereby maintaining a high probability of successfully completing a lane change. Furthermore, the detection area can be stabilized, preventing the host vehicle from approaching a following vehicle. For example, when the host vehicle is traveling in a high-speed range (90-130 km / h), the acceleration G acting on the host vehicle tends to be large. Increasing the braking force limit is preferable to reduce the relative speed difference between the host vehicle and a following vehicle. Furthermore, decelerating the host vehicle while traveling at high speed tends to shorten the distance between the host vehicle and another vehicle. The control to increase the braking force limit is preferably performed early. When the host vehicle is traveling in a medium-speed range (45-90 km / h), the lane change behavior can be adjusted, allowing the lane change to be completed at a timing consistent with the driving plan. When the host vehicle is traveling in a low-speed range (15 km / h or less), the amount of movement is small, so a lane change is performed by steering the vehicle to a large amount and creating a yaw angle. In this case, if you try to delay the timing by braking, you will have to turn the steering wheel even more, which will significantly increase the amount of steering required. This will result in a sudden steering that is different from the steering that the driver is steering, which will make the driver feel uncomfortable.For this reason, it is preferable to increase the braking force limit at low speeds and allow an increase in the amount of steering angle to maintain the reference time. In addition, the reference time may be allowed to be increased (longer) than that (reference time) when the vehicle is in the medium speed range so that it is equal to or shorter than the reference time required from the start to completion of a lane change. This allows for greater suppression of braking force. Furthermore, in this control, when the vehicle is traveling around a curve, the amount of braking that limits driving of the vehicle toward the inside of the curve may be greater than the amount of braking that limits driving of the vehicle toward the outside of the curve. Because the lateral G / steering speed on the outside of the curve tends to increase, it is possible to prevent vehicle behavior from exceeding the limit amount.

[0036] The processor 10 calculates the predetermined value according to the lateral position after the start of the lane change. The processor 10 calculates the predetermined value so that the predetermined value when the distance along the road width direction between the host vehicle changing lanes and the second lane is short is higher than the predetermined value when the distance is long. This control targets a scene in which the host vehicle, which was traveling in the center of the first lane at the start of the lane change, moves laterally along the road width direction and approaches the center of the second lane to complete the lane change. The processor 10 sets a relatively high predetermined value at a lateral position close to the completion of the lane change so that the braking force limiting value at the lateral position close to the completion of the lane change is smaller than the braking force limiting value at a lateral position far from the completion of the lane change. When the lane change is close to completion, the impact of deceleration due to the driver's braking operation on driving along the planned trajectory is small. Therefore, by increasing the predetermined value, the braking force limiting value is reduced, allowing driving that prioritizes the driver's operation.

[0037] The processor 10 calculates a predetermined value according to the detection result when changing lanes. The processor 10 calculates the predetermined value so that the predetermined value when sensor 2, which detects objects within a predetermined range, receives detection information indicating that a vehicle in the second lane is not detected is lower than the predetermined value when sensor 2 receives detection information indicating that a vehicle in the second lane is detected. The braking force limited when sensor 2 receives detection information indicating that a vehicle in the second lane is not detected is greater than the braking force limited when sensor 2 receives detection information indicating that a vehicle in the second lane is detected. The sensor 2 detects objects that exist within a predetermined range according to its detection performance. Objects that exist beyond the predetermined range cannot be detected, but the output of sensor 2 indicates that the object was not detected. The predetermined detection range may change due to changes in the speed of the host vehicle or the other vehicle, and a vehicle may change lanes from an adjacent lane to the second lane and enter the predetermined range. The detection information indicating that a vehicle in the second lane is not detected does not mean that a vehicle is actually not present in the second lane, but may change to a detection result indicating that a vehicle is present depending on future changes in the situation. On the other hand, the possibility that the detection information indicating that another vehicle in the second lane has been detected is low and the reliability of the detection information can be said to be relatively high. When another vehicle in the second lane is not detected, the predetermined value can be lowered in consideration of fluctuations in the detection results, thereby ensuring a large braking force limit and maintaining a high possibility of completing the lane change. When another vehicle is detected, the predetermined value can be increased to reduce the braking force limit, allowing driving that prioritizes driver operation.

[0038] 100... driving control system, 1... driving control device, 10... processor, 11... CPU, 12... ROM, 13... RAM, 20... input / output device, 30... communication device, 2... sensor, 21... camera, 22... radar device, 3... vehicle information acquisition device, 4... other vehicle information acquisition device, 5... map information, 51... lane information, 6... navigation device, 200... vehicle controller, 210... steering control device, 220... drive control device

Claims

1. A driving control method used in a processor to execute autonomous driving control of a host vehicle, wherein the processor increases the steering amount of the host vehicle when the deceleration amount input by a braking operation of the driver of the host vehicle is high during execution of a lane change for moving the host vehicle from a first lane in which the host vehicle is traveling to a second lane, as compared to when the deceleration amount is low.

2. The driving control method according to claim 1, wherein the processor increases the steering amount so that a target time for moving the host vehicle from the first lane to the second lane is equal to or less than a preset reference time.

3. The driving control method according to claim 1 or 2, wherein when the deceleration amount is equal to or greater than a preset predetermined value, the processor limits a braking force corresponding to an excess deceleration amount of the deceleration amount with respect to the predetermined value.

4. The driving control method according to claim 3, wherein the processor determines whether the lane change from the first lane to the second lane is a first lane change that is essential and must be executed, and calculates the predetermined value so that the predetermined value in the case where it is determined that the lane change is the first lane change is higher than the predetermined value in the case where it is determined that the lane change is a second lane change that is not the first lane change.

5. The driving control method according to claim 3, wherein the processor calculates the predetermined value so that the predetermined value when the vehicle speed of the host vehicle is high when the braking operation by the driver is input is lower than the predetermined value when the vehicle speed of the host vehicle is low.

6. The driving control method according to claim 3, wherein the processor calculates the predetermined value so that the predetermined value when the distance along the road width direction between the host vehicle about to change lanes and the second lane is short is higher than the predetermined value when the distance is long.

7. The driving control method according to claim 3, wherein the processor calculates the predetermined value so that the predetermined value when detection information indicating that other vehicles in the second lane are not detected is obtained from a sensor that detects an object in a predetermined range is lower than the predetermined value when detection information indicating that other vehicles in the second lane are detected is obtained.

8. The driving control method according to any one of claims 1 to 7, wherein the processor determines whether the lane change from the first lane to the second lane is a first lane change that is essential and must be executed, and when it is determined that the lane change is the first lane change, the processor executes the driving control.

9. The driving control method according to any one of claims 1 to 7, wherein the processor executes the driving control when a rear vehicle approaching the host vehicle is detected in the second lane.

10. The driving control method according to any one of claims 1 to 7, wherein the processor executes the driving control when a following vehicle is detected behind the first lane.

11. The driving control method according to any one of claims 1 to 10, wherein the processor aborts the execution of the driving control when the deceleration amount required by the braking operation by the driver is equal to or greater than an allowable value when a rear vehicle approaching the host vehicle is detected in the second lane.

12. A driving control device including a processor that causes the host vehicle to execute autonomous driving control, wherein the processor increases the steering amount of the host vehicle more when the deceleration amount input by the braking operation of the driver of the host vehicle is high than when the deceleration amount is low during execution of a lane change for moving the host vehicle from a first lane in which the host vehicle is traveling to a second lane.

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