Travel control device for operational service vehicles

Abstract

To provide a travel control device for operational service vehicles that can prevent passengers from feeling uneasy or losing comfort while being prepared for the unexpected entry of traffic participants into a travel route, and has a small computational load.SOLUTION: A travel control device includes: a driving operation determination unit that determines a target route based on a global route and a road environment near a vehicle; and a control unit that performs speed control and steering control to follow the target route. The travel control device can selectively execute a first alert mode in which the vehicle maintains its lane and travels at a lower speed than normal traveling, and a second alert mode in which the vehicle maintains a normal traveling speed and changes lanes to the side away from an approachable area when the approachable area exists in front of the vehicle, and is configured to execute the second alert mode in the case that a predetermined lane change condition is satisfied when the vehicle is not in service, and executes the first alert mode in the case that the vehicle is in service or the predetermined lane change condition is not satisfied.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a travel control device for a vehicle for an operation service, particularly for an autonomous vehicle for an operation service.

Background Art

[0002] Various forms of operation services by autonomous vehicles, such as scheduled fixed-route type, on-demand type, fixed-route on-demand type, etc., have been proposed. The travel route of an autonomous vehicle is determined by combining a predetermined global route (global path; a route from a start point to a goal point, etc.) and a local route (local path; obstacle avoidance, temporary lane change, stop and start at an intersection, etc.) determined according to the road environment near the vehicle. For example, when recognizing surrounding traffic participants (moving bodies; vehicles, pedestrians, bicycles, etc.) and predicting that they will become obstacles, countermeasures such as route change or stop for avoidance are required.

[0003] Among traffic participants, vehicles travel according to the travel section specified by the lane markings and road structure and traffic regulations, so they do not exist as obstacles like parked vehicles, and as long as the inter-vehicle distance from the vehicle ahead is ensured, they will not immediately become obstacles. However, in the case of pedestrians, although there are passage sections such as sidewalks and road shoulders, it is difficult to predict their behavior compared to vehicles, and it is also difficult to determine whether they will become obstacles.

[0004] Patent Document 1 discloses setting a risk area (risk potential) for a traffic participant (pedestrian) recognized by a recognition unit, correcting the risk area based on the target environment such as the width of the sidewalk and the width of the lane, and the attributes of the traffic participant, and performing speed control and steering control of the vehicle based on the corrected risk area.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In a method of setting a risk area for traffic participants (pedestrians), when the risk area is corrected based on the target environment, the evaluation targets finally reflected in the control will be reduced. However, the processing targets for setting the risk area are not reduced, and there is a problem that the computational load increases according to the recognition range and the number of traffic participants.

[0007] In addition, if the driving route changes each time dealing with individual traffic participants at the warning level, it may affect the surrounding vehicles and there are also concerns about affecting the sense of security and comfort of passengers and crew. In particular, in vehicles assuming a ride service such as a vehicle for an operation service, problems such as an increase in the sense of uneasiness of passengers and a decrease in comfort can be prior issues.

[0008] The present invention has been made in view of the above actual situation, and its object is to adapt to the operation mode of a vehicle for an operation service, prepare for unexpected entry of traffic participants into the driving route, prevent uneasiness and comfort degradation for passengers, and provide a driving control device for a vehicle for an operation service with a small computational load.

Means for Solving the Problems

[0009] In order to solve the above problems, the present invention is a driving control device for a vehicle for an operation service, comprising a driving operation determination unit that determines a target route based on a predetermined global route and the road environment near the vehicle, and a control unit that performs speed control and steering control so as to follow the target route. When there is an entry possible area where other traffic participants may enter the roadway in front of the vehicle, the driving operation determination unit is prepared to selectively execute a first warning mode in which the vehicle travels at a speed lower than normal while maintaining the lane, or a second warning mode in which the vehicle changes lanes to the side away from the entry possible area while maintaining the speed of normal driving, and When a predetermined lane change condition is satisfied when the service is not in operation, the second warning mode is executed, A travel control device is configured to execute the first warning mode when the service is in operation or when a predetermined lane change condition is not satisfied.

Advantages of the Invention

[0010] As described above, the vehicle travel control device according to the present invention executes the first warning mode in which the vehicle travels at a low speed while maintaining the lane during service operation when there is an accessible area in front of the vehicle. By doing so, it is possible to prevent a sense of unease and a decrease in comfort for passengers while preparing for an unexpected entry of a traffic participant into the travel route. On the other hand, when the service is not in operation and lane change is possible, the second warning mode in which the vehicle changes lanes to the side away from the accessible area while maintaining the speed is executed. By doing so, it is possible to maintain the recovery efficiency while preparing for an unexpected entry of a traffic participant into the travel route. Instead of dealing with pedestrians for whom behavior prediction is difficult individually at the warning level, by dealing with them in a travel mode (warning mode) considering the road structure and operating conditions, there is an advantage that the computational load can be kept smaller compared to the case of dealing with them individually at the warning level.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, an automatic driving system 10 that constitutes a driving control device of a vehicle 1 according to an embodiment of the present invention includes an external information acquisition unit 11, a vehicle information acquisition unit 12, a road information acquisition unit 13, a driving information acquisition unit 14, a high-precision map 15, a driving operation determination unit 16, and a control unit 17.

[0013] The external information acquisition unit 11 extracts information required by the driving operation determination unit 16 from the data received from an external sensor 21 composed of a plurality of sensors, and processes it into a format for ambient environment recognition (lane recognition, road structure recognition, moving object detection, traffic signal and road sign recognition). A series of processes are executed, updated, and stored in a storage device at a predetermined time rate.

[0014] As the external sensor 21, LiDAR for detecting moving objects (vehicles, bicycles, pedestrians, etc.), stationary objects (obstacles, parked vehicles, etc.), road structures (curbs, median strips, guardrails, traffic signals, barriers, etc.), buildings (outer walls, utility poles, trees, etc.) around the vehicle, radar (millimeter wave radar, infrared radar), cameras (image sensors such as monocular cameras and stereo cameras), GNSS (global navigation satellite system) for detecting the position of the host vehicle, an acceleration sensor and a gyro sensor for detecting the three-dimensional motion and attitude of the host vehicle, or an IMU (inertial measurement unit) integrating them, etc. are provided.

[0015] The vehicle information acquisition unit 12 acquires the detection values of an internal sensor 22 composed of a group of sensors that determine the motion state of the vehicle 1, such as a vehicle speed sensor, an acceleration sensor, a yaw rate sensor, a steering angle sensor, an accelerator sensor, and a brake sensor, via in-vehicle communication (in-vehicle network), extracts information required by the driving operation determination unit 16 according to each control purpose, and processes it into a format that can be used by the driving operation determination unit 16. A series of processes are executed, updated, and stored in a storage device at a predetermined time rate.

[0016] The road information acquisition unit 13 extracts information required by the driving operation determination unit 16 from data received via the I2V receiver 23 through broadcast-type information distribution, V2I vehicle-road communication, mobile communication using a cellular communication network, etc., which is distributed from communication infrastructure (roadside infrastructure) installed on the road. For example, from traffic information such as signal information at intersections, information on surrounding vehicles, lane regulations and speed limits related to position information, and processes it into a format that can be used by the driving operation determination unit 16. A series of processes are executed, updated, and stored in the storage device at a predetermined time rate.

[0017] The driving information acquisition unit 14 extracts information required by the driving operation determination unit 16 from data received through mobile communication with the management center 24 of the autonomous vehicle 1, such as route update information, reservation information such as boarding and alighting locations and times, user information, authentication information, etc., and processes it into a format that can be used by the driving operation determination unit 16 according to each purpose. A series of processes are executed, updated, and stored in the storage device at a predetermined time rate.

[0018] The management center 24 is a management center that comprehensively manages the operation service by the autonomous vehicle 1, manages the entire operation service such as the current position of the autonomous vehicle 1, and communicates information with each autonomous vehicle.

[0019] The high-precision map 15 is a map system (database) having a plurality of data layers including position information of a road network covering the area where the autonomous vehicle 1 travels, road structure, three-dimensional information such as surrounding structures and trees, driving lane information, legal information such as speed limits, parking bans, overtaking bans, and the presence or absence of accessible areas for entering lanes, etc., which are information necessary for autonomous driving.

[0020] Note that the accessible area (i.e., the warning area), which is the criterion for determining the driving modes (warning mode 1 and warning mode 2) described later, is determined based on the presence or absence of structures (such as guardrails, plantings, curbs, etc.) between the roadway and the sidewalk, the height of the structures, the distance and gaps between structures, etc. For example, if there is a guardrail with a height of 50 cm or more, entry is not possible (it is not an accessible area), and if the gap between a utility pole and a guardrail is less than a predetermined value (e.g., 30 cm), entry is not possible (it is not an accessible area), and so on.

[0021] FIG. 3 shows an example of a road structure having accessible areas 56 and 57. In this example, guardrails 53, 54, and 55 are intermittently provided at the boundary between the sidewalk 50 on the side of the road 5 having the first lane 51 and the second lane 52, and accessible areas 56 and 57 where pedestrians can enter from the sidewalk 50 into the road 5 (51) are formed between them. These determinations are set and updated based on the external information acquired by the external information acquisition unit 11 in addition to the map information of the high-precision map 15.

[0022] The driving operation determination unit 16 includes units that execute each process of surrounding environment recognition, own vehicle position estimation, and route planning of the autonomous vehicle 1, and determines a target route based on a global route (route or global path) based on a pre-determined driving plan and a local route (local path) corresponding to the driving mode specified according to the road environment and driving conditions in the vicinity of the vehicle.

[0023] The surrounding environment recognition unit 61 integrates the external information acquired by the external information acquisition unit 11, that is, information on moving objects (such as vehicles, bicycles, pedestrians, etc.), stationary objects (such as obstacles, parked vehicles, etc.), road structures (such as curbs, median strips, guardrails, traffic signals, barriers, etc.), and buildings (such as outer walls, utility poles, trees, etc.) around the vehicle, and executes surrounding environment recognition (lane recognition, road structure recognition, moving object detection, traffic signal and road sign recognition) processing of the autonomous vehicle 1.

[0024] The host vehicle position estimation unit 62 estimates the position (e.g., coordinate values X, Y, Z, or latitude and longitude) and the traveling direction (yaw angle) of the automated driving vehicle 1 on the map. As estimation methods, a method of estimation by matching the measurement point cloud of the LiDAR that constitutes the external sensor 21 with the point cloud of the high-precision map 15 (e.g., the NDT matching method (Normal Distribution Transform)), a method of estimation by matching the feature points extracted from the camera image with the point cloud of the high-precision map 15 (e.g., Visual SLAM "Simultaneous Localization and Mapping"), a method of estimation from the latitude and longitude detected by GNSS, and a method of estimation from the movement amount and rotation amount of the vehicle obtained from the vehicle speed and yaw rate (e.g., the Dead Reckoning method) can be used.

[0025] The travel route configuration unit 63 determines the target route along which the automated driving vehicle 1 should travel based on the position and attitude of the automated driving vehicle 1 determined by the host vehicle position estimation unit 62 and the surrounding environment recognized by the surrounding environment recognition unit 61, and according to the driving mode determined by the driving situation determination unit 64.

[0026] The driving situation determination unit 64 selects one of the normal driving mode, warning mode 1, and warning mode 2 according to the surrounding environment and driving conditions of the automated driving vehicle 1. As the criteria for determining the driving mode, in addition to the presence or absence of an accessible area, there are driving conditions such as whether a passenger is on board, whether it is in the middle of a driving service, whether it is operating on a fixed route at fixed times, and lane change conditions such as the presence or absence of an adjacent lane and the presence or absence of a vehicle traveling in a predetermined area of the adjacent lane. Each driving mode is as follows.

[0027] In the normal driving mode, as shown in Fig. 2(a), it travels at a medium to high set speed (Vm) while maintaining the first lane (left lane). When there is a preceding vehicle traveling at a speed equal to or lower than the set speed, it follows the preceding vehicle while maintaining the set inter-vehicle time.

[0028] As shown in Fig. 2(b), when there is an accessible area (56) in front of the vehicle and a predetermined transition condition is satisfied, the warning mode 1 runs at a low set speed (Vlow) while maintaining the first lane (left lane), and is prepared for the entry of other traffic participants into the own lane to prevent a collision with the traffic participants. Also in this case, when there is a preceding vehicle running at a speed equal to or lower than the set speed, the set inter-vehicle time with the preceding vehicle is maintained and the vehicle follows the preceding vehicle.

[0029] As shown in Figs. 2(c1) and (c2), when there is an accessible area in front of the vehicle and a predetermined transition condition is satisfied, the warning mode 2 changes lanes to the second lane (right lane) away from the accessible area and runs at a medium-high set speed (Vm). Also in this case, when there is a preceding vehicle running at a speed equal to or lower than the set speed, the set inter-vehicle time with the preceding vehicle is maintained and the vehicle follows the preceding vehicle.

[0030] The operation mode route generation unit 65 generates a driving route according to the driving mode (any one of the normal driving mode, warning mode 1, and warning mode 2) selected by the operation status determination unit 64, from a driving vehicle speed pattern that maintains the first lane, a route and a driving vehicle speed pattern that changes lanes to the second lane, and a route and a vehicle speed pattern that changes lanes from the second lane to the first lane.

[0031] Basically, in the warning mode 2, at the time of shifting to the warning mode 2, as shown in Fig. 2(c2), a route is set to change lanes to the second lane (right lane), run for a certain section (predetermined time), and then return to the first lane (left lane). However, as shown in Fig. 2(c1), when the accessible areas (56, 57) are continuous at intervals shorter than a predetermined distance D, the running in the second lane (right lane) is continued for a further certain section (predetermined time), and then the vehicle changes lanes to the first lane (left lane) and returns to the normal driving mode.

[0032] Also, although not shown in the drawings, even in warning mode 1, when the accessible areas (56, 57) are continuous at short intervals less than a predetermined distance D, the vehicle may continue to travel at a low set speed (Vlow) and return to the normal driving mode when there is no accessible area. In this case, the predetermined distance D for determining the continuation of warning mode 1 can be the same as or shorter than the predetermined distance D for determining the continuation of warning mode 2.

[0033] The control unit 17 includes a lateral control unit 71 that outputs a steering angle command for giving a target steering angle for the vehicle 1 to follow the target path determined by the driving operation determination unit 16 to the steering unit 31, and a longitudinal control unit 72 that outputs a speed command (acceleration / deceleration command) for achieving the target speed to the drive unit 32 and the brake unit 33.

[0034] Each unit constituting the automatic driving system 10 as described above is implemented as a computer (ECU) including a ROM that stores a program operable to execute each function, a CPU that performs arithmetic processing, a RAM that serves as a work area for reading the program and a temporary storage area for arithmetic results of the CPU, and an input / output interface.

[0035] The steering unit 31 is composed of a steering mechanism including a steering wheel and a steering actuator (EPS motor constituting an electric power steering system). The drive unit 32 is composed of an internal combustion engine and an engine controller in the case of an internal combustion engine vehicle, a motor generator and a motor controller in the case of an electric vehicle, and those and a hybrid controller in the case of a hybrid vehicle. The brake unit 33 is composed of a brake device for braking each wheel, a brake actuator, a brake controller (ESC controller), etc.

[0036] (First Embodiment) FIG. 4 is a flowchart showing the flow of operation status determination according to the first embodiment. During the running of the vehicle 1, such determination operations are continuously executed at a predetermined time rate.

[0037] First, sensor information and vehicle information that serve as the basis for determination are acquired from the external information acquisition unit 11 and the vehicle information acquisition unit 12, compared with the map information of the high-precision map 15 through surrounding environment recognition and own vehicle position estimation, and the road structure in front of the vehicle and the surrounding vehicles and traffic participants are monitored (step 100).

[0038] At the same time, the operation information acquired through the operation information acquisition unit 14 is referred to (step 101), and the road information acquired by the road information acquisition unit 13 is referred to (step 102).

[0039] If there is no accessible area on the road ahead of the vehicle (step 103; NO), the normal driving mode is selected, and driving in the normal driving mode is continued (step 120).

[0040] If there is an accessible area on the road ahead of the vehicle (step 103; YES), it is checked whether the operating conditions (service operating conditions) of vehicle 1 are satisfied. If the service operating conditions are satisfied, such as regular scheduled route operation or in-service operation (step 110; YES), and there are passengers in the vehicle (step 111; YES), warning mode 1 is selected, and the vehicle shifts to low-speed driving while maintaining the lane (step 121).

[0041] If the operating conditions (service operating conditions) are not satisfied, such as when vehicle 1 is being towed (step 110; NO), or even if the service operating conditions are satisfied (step 110; YES), but there are no passengers in the vehicle (step 111; NO), and the lane change conditions are satisfied, such as when there are no other vehicles in a predetermined range of the adjacent lane (step 112; YES), warning mode 2 is selected, and after the turn signal blinks, a lane change to the second lane is executed (step 122).

[0042] On the other hand, if the lane change conditions are not satisfied, such as when there are other vehicles in a predetermined range of the adjacent lane (step 112; NO), warning mode 1 is selected, and the vehicle shifts to low-speed driving while maintaining the lane (step 121).

[0043] In order to avoid the repeated occurrence of speed changes associated with the transition to warning mode 1 and lane changes associated with the transition to warning mode 2 within a short period, as previously described, after the transition to warning modes 1 and 2, driving in these warning modes 1 and 2 continues for a certain period (predetermined time). In that case, mode changes may be prohibited for the predetermined time so as not to be reflected in the driving control.

[0044] As operation service vehicles, in addition to regular fixed-route operation vehicles such as route buses, there are also on-demand vehicles such as taxis, and furthermore, there are several operation forms such as shared taxis (pool taxis) which are intermediate operation forms between them, and the determination conditions can be changed according to the operation form.

[0045] For example, in the above embodiment, it was shown that when there are no passengers even during regular fixed-route operation, warning mode 2 is selected by regarding it as the same as when in deadheading, but when the operation conditions are met, warning mode 1 may be selected regardless of the presence or absence of passengers.

[0046] (Second Embodiment) FIG. 5 is a flowchart showing the flow of operation status determination according to the second embodiment. The basic flow from step 100 to step 103 is the same as that of the first embodiment described above, but for the determination of warning modes 1 and 2, a scoring table with weights assigned to each condition in advance is set.

[0047] (Operation Conditions) (YES)(NO) Service Operation -3 +2 Regular Fixed-Route Operation -2 +2 With Passengers -1 +1 With Rear Vehicles -1 +1 With Speed Limit -1 +1

[0048] When there is an accessible area on the road ahead of the vehicle (step 103; YES), the scores of the respective driving conditions are aggregated (step 114). If the total score is less than a predetermined threshold (for example, zero) (step 115; YES), warning mode 1 is selected (step 121). If the total score is greater than or equal to the predetermined threshold (for example, zero) (step 115; NO), warning mode 2 is selected (step 122).

[0049] In this embodiment, in addition to the driving conditions, road environment conditions are also added. Furthermore, depending on the operation mode, conditions such as time zone, weather, presence or degree of delay in operation time (fixed time and fixed route type), presence or absence of reservation for boarding and alighting at the next stop (shared taxi), etc. can be appropriately added.

[0050] As described above, when there is an accessible area in front of the vehicle, the vehicle driving control device according to the present invention executes the first warning mode of driving at a low speed while maintaining the lane during service operation, thereby preventing unexpected entry of traffic participants into the driving route while preventing discomfort and reduction in comfort for passengers.

[0051] On the other hand, when not in service operation, if lane change is possible, the second warning mode of changing lanes to the side away from the accessible area while maintaining the speed is executed, thereby preventing unexpected entry of traffic participants into the driving route while preventing a decrease in the vehicle's return efficiency and delivery efficiency.

[0052] Moreover, instead of dealing with pedestrians individually at the warning level, by dealing with them in warning modes 1 and 2 considering the road structure and driving conditions, the computational load can be kept smaller compared to dealing with them individually at the warning level, and system resources can be utilized for other processes, such as fault detection and surrounding environment recognition.

[0053] Also, even during service operation, when there are no passengers, there is no need to consider the comfort of passengers. Therefore, by executing the second warning mode when the lane change condition is satisfied, it is possible to be prepared for unexpected entry of traffic participants into the driving route while maintaining good vehicle return efficiency and delivery efficiency.

[0054] On the other hand, even when the lane change condition is satisfied but the service is not in operation, if there is a speed limit lower than normal driving in the driving section, by executing the first warning mode, it is possible to prevent unexpected entry of traffic participants into the driving route and prevent discomfort and reduced comfort for passengers.

[0055] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and various modifications and changes are possible within the scope of the claims of the present invention based on the technical idea of the present invention.

Explanation of Signs

[0056] 1 Vehicle 5 Road 10 Automated driving system 11 External information acquisition unit 12 Vehicle information acquisition unit 13 Road information acquisition unit 14 Driving information acquisition unit 15 High-precision map 16 Driving operation decision unit 17 Control unit 21 External sensor 22 Internal sensor 23 I2V receiver 24 Management center 31 Steering unit 32 Driving unit 33 Braking unit 50 Sidewalk (roadside space) 51 First lane 52 Second lane 53, 54, 55 Guardrail 56, 57 Enterable area 61 Surrounding environment recognition unit 62 Own vehicle position estimation unit 63 Driving route configuration unit 64 Driving situation determination unit 65 Driving mode route generation unit

Claims

1. A driving control device for a vehicle used for a running service, comprising: a driving operation determination unit that determines a target route based on a predetermined global route and the road environment in the vicinity of the vehicle; and a control unit that performs speed control and steering control so as to follow the target route. When there is an accessible area where other traffic participants may enter the lane ahead of the vehicle, the driving operation determination unit is prepared to selectively execute a first warning mode in which the vehicle travels at a speed lower than normal while maintaining the lane, or a second warning mode in which the vehicle changes lanes to the side away from the accessible area while maintaining the normal running speed. Also, When a predetermined lane change condition is satisfied when the service is not in operation, the second warning mode is executed. A driving control device configured to execute the first warning mode when the service is in operation or when the predetermined lane change condition is not satisfied.

2. The driving control device according to claim 1, wherein when there are no passengers even during the service operation and the lane change condition is satisfied, the second warning mode is executed.

3. The driving control device according to claim 1, wherein even when the service is not in operation and the lane change condition is satisfied, the first warning mode is executed in a section where there is a speed limit lower than the normal running speed.

4. When passing through the accessible area in the first warning mode, if the distance or estimated required time to the next accessible area is equal to or greater than a first predetermined value, the first warning mode is terminated and the vehicle returns to normal running. if the distance or estimated required time to the next accessible area is less than the first predetermined value, the first warning mode is maintained. The driving control device according to claim 1.

5. When passing through the accessible area in the second warning mode, if the distance or estimated required time to the next accessible area is equal to or greater than a second predetermined value, the vehicle changes lanes back to the original lane considering the lane change condition, terminates the second warning mode, and returns to normal running. if the distance or estimated required time to the next accessible area is less than the second predetermined value, the second warning mode is maintained. The driving control device according to claim 1.

6. A driving control device for a vehicle used for a running service, comprising: a driving operation determination unit that determines a target route based on a predetermined global route and the road environment in the vicinity of the vehicle; and a control unit that performs speed control and steering control so as to follow the target route. When there is an accessible area where other traffic participants may enter the lane in front of the vehicle, the driving operation determination unit is prepared to selectively execute a first warning mode in which the vehicle travels at a speed lower than normal driving while maintaining the lane, or a second warning mode in which the vehicle changes lanes to the side away from the accessible area while maintaining the normal driving speed. Also, at least, a step of summing scores weighted for each of the driving conditions including whether or not it is during service operation, whether or not it is regular route operation, whether or not there are passengers, and whether or not a predetermined lane change condition is satisfied is executed. A driving control device configured to execute the second warning mode when the sum of the scores is equal to or greater than a predetermined value, and to execute the first warning mode when the sum of the scores is less than the predetermined value.

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