Travel control device for vehicle

Abstract

To reduce the risk of contact or collision with surrounding structures or other traffic participants in an annular intersection by suppressing excessive override during autonomous driving within the annular intersection.SOLUTION: A travel control device for vehicle includes: an MRM function that executes risk minimization control including decelerating and stopping the vehicle within a lane when a system failure occurs during operation of an autonomous driving function; an EM function that executes emergency avoidance control including activation of emergency braking when a collision with an obstacle existing around the vehicle is expected; and an override function that, when an operational intervention exceeding a predetermined threshold by a driver occurs during operation of the autonomous driving function, the MRM function, or the EM function, stops the function in operation and transfers authority to the driver. The override function sets the predetermined threshold for activation of the override function to different values between a case where the vehicle is traveling inside an annular intersection or traveling outside the annular intersection.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a vehicle driving control device, and more particularly to vehicle driving control during operation of risk minimization control in the event of a system failure and emergency avoidance control for avoiding a collision with an obstacle. [Background technology]

[0002] Development of technologies that allow vehicles to be driven by automated driving systems under specific conditions is underway. Cruise control devices that drive vehicles autonomously using automated driving systems have a Minimal Risk Maneuver (MRM) function that executes risk minimization control, such as slowing and stopping the vehicle within its lane or moving it to the shoulder, if a system failure occurs during autonomous driving. Cruise control devices also have an Emergency Maneuver (EM) function that switches to emergency avoidance control to avoid a collision if a collision with an obstacle is predicted. The EM function is configured to avoid danger by, for example, using maximum deceleration and steering in combination to slow and stop the vehicle within its lane or move it to the shoulder. Cruise control devices are typically configured to prioritize the override operation and transfer control authority to the driver if the driver attempts an override operation while an automated driving function, including the MRM and EM functions, is in operation.

[0003] For example, Patent Document 1 discloses a driving assistance device that, when a driver performs a steering operation while collision avoidance braking control and / or lane departure prevention control are being executed, terminates the corresponding collision avoidance braking control and / or lane departure prevention control under the establishment of a steering override condition, and executes a steering override that prioritizes the driver's steering operation.If it is determined that the steering direction when steered wheels are steered by lane departure prevention control is the same as the collision avoidance direction by collision avoidance braking control, the steering-related threshold is increased from a first steering-related threshold to a second steering-related threshold, so that the steering override condition is less likely to be established even if the driver performs a steering operation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-094955 Summary of the Invention [Problem to be solved by the invention]

[0005] A roundabout is a type of intersection installed on roads. A roundabout connects multiple roads via a circular space, and is configured so that vehicles travel in one direction around a circular road around a central island in the center of the circular space. At a roundabout, vehicles travel around the circular road and exit through an exit that leads to their destination road. If the MRM or EM function is activated while a vehicle is traveling through a roundabout using automated driving, the driver may panic when the MRM or EM function starts to activate, causing an override by performing excessive driving operations. If such an excessive override is performed while traveling through a roundabout, there is a risk of contact or collision with structures surrounding the roundabout or other vehicles.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and its purpose is to reduce the risk of contact or collision with surrounding structures or other traffic participants at a roundabout by suppressing excessive override while driving within the roundabout through automated driving. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a driving control device for a vehicle equipped with an automatic operation device for executing an automatic driving function, the driving control device having an MRM function that performs risk minimization control, including decelerating and stopping the vehicle within its lane, if a system failure occurs while the automatic driving function is operating; an EM function that performs emergency avoidance control, including activating the emergency brake, if a collision with an obstacle around the vehicle is predicted while the automatic driving function is operating; and an override function that stops the function in operation and transfers authority to the driver if the driver intervenes in an operation above a predetermined threshold while the automatic driving function, the MRM function, or the EM function is operating, and the override function is configured to set the predetermined threshold for activating the override function to different values when the vehicle is traveling within a roundabout and when it is traveling outside the roundabout. [Effects of the Invention]

[0008] The vehicle driving control device of the present invention can reduce the risk of traffic flow disruption and contact / collision with other traffic participants at a roundabout by suppressing excessive override while the vehicle is driving automatically through the roundabout. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing a vehicle driving control device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic plan view showing a group of external sensors of a vehicle. [Figure 3] FIG. 3 is a block diagram showing a vehicle driving control device. [Figure 4] FIG. 4 is a diagram illustrating the behavior of a vehicle when the MRM function or the EM function is activated in a roundabout. [Figure 5] FIG. 5 is a flowchart illustrating the flow of control in this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] -First embodiment- A first embodiment of the present invention will be described in detail below with reference to the drawings. A cruise control device for a vehicle 1 according to this embodiment is configured to be capable of performing automated driving equivalent to SAE (Society of Automotive Engineers) Level 4, which performs all driving operations within an operational design domain (ODD). The cruise control device for a vehicle 1 according to this embodiment can also be configured to communicate with a remote control base station via a communication device (not shown) and perform automated driving through remote monitoring and remote operation by the remote control base station.

[0011] 1 to 3, a vehicle 1 equipped with a cruise control device according to this embodiment includes, in addition to typical automobile components such as an engine and a body, external sensors 21 that detect the environment around the vehicle, internal sensors 22 that detect vehicle information, a map information database 23, positioning means 24, a group of controllers / actuators for speed control and steering control, an ACC controller 15 for controlling the distance between vehicles, an automatic steering controller 16 for automatic steering control, and an automatic driving device 10 that controls these components to execute route following control, in order to perform the recognition, judgment, and operation that have traditionally been performed by a driver on the vehicle side.

[0012] The controller / actuator group for speed control and steering control includes an EPS (electric power steering) controller 31 for steering control, an engine controller 32 for acceleration / deceleration control, and an ESP / ABS controller 33. ESP (registered trademark; Electronic Stability Program) includes ABS (anti-lock braking system) to form a stability control system (vehicle behavior stabilization control system).

[0013] The external environment sensor 21 consists of multiple detection means for inputting the presence and relative distance of road dividing lines that define the current lane and adjacent lanes, other vehicles, obstacles, people, etc. around the current vehicle as external environment data such as image data or point cloud data into the automatic driving device 10.

[0014] For example, as shown in Fig. 2, the vehicle 1 is equipped with a millimeter-wave radar (211) and a camera (212) as forward detection means 211, 212, a LIDAR (laser image detection / ranging) as front-side detection means 213 and rear-side detection means 214, and a camera (back camera) as rear detection means 215. The external sensor 21 covers 360 degrees around the vehicle and is capable of detecting the positions and distances of other vehicles and obstacles within a predetermined range in the front, rear, left and right directions of the vehicle, as well as the positions of lane markings in the vehicle's lane and adjacent lanes. Note that millimeter-wave radar (or LIDAR) can also be added as rear detection means.

[0015] The internal sensor 22 is made up of a plurality of detection means for measuring physical quantities that represent the motion state of the vehicle, such as a vehicle speed sensor, a yaw rate sensor, an acceleration sensor, etc. As shown in Fig. 3, the measured values of the internal sensor 22 are input to the automatic driving device 10, the ACC controller 15, the automatic steering controller 16, and the EPS controller 31, and are processed together with the input from the external sensor 21.

[0016] The external sensor 21 and the internal sensor 22 are configured to start operating at the same time as the start of the vehicle 1, and to constantly detect the surrounding environment and vehicle information.

[0017] The automatic driving device 10 includes an environmental state estimation unit 11, an override threshold change unit 12, a route generation unit 13, and a vehicle control unit 14, and is composed of a computer for performing the functions described below, namely, a ROM that stores programs and data, a CPU that performs calculation processing, a RAM that reads the programs and data and stores dynamic data and calculation processing results, and an input / output interface.

[0018] The environmental state estimation unit 11 acquires the absolute position of the vehicle by matching the vehicle position information obtained by a positioning means 24 such as a Global Navigation Satellite System (GNSS) with the map information in the map information database 23. The environmental state estimation unit 11 estimates the positions of the lane markings of the vehicle's lane and adjacent lanes, and the positions and speeds of other vehicles, based on external data such as image data and point cloud data acquired by an external sensor 21.

[0019] Note that the environmental state estimation unit 11 can also be configured to use SLAM (Simultaneous Localization and Mapping) to estimate the current position of the vehicle 1, instead of acquiring the absolute position of the vehicle 1 based on the vehicle position information from the positioning means 24 and the map information in the map information database 23, or to obtain the relative position of the vehicle 1 with respect to the dividing line between adjacent lanes obtained from the camera 212 included in the external sensor 21. The camera 212 included in the external sensor 21, or the positioning means 24 such as GNSS, etc., constitute a position detection unit that detects the current position of the vehicle 1.

[0020] The environmental state estimation unit 11 is further configured to acquire information about road shapes, such as whether or not a roundabout exists on the road and whether or not there is an evacuation space around the roundabout where the vehicle can stop, based on map information from the map information database 23, for example. Roundabouts will be described later. The environmental state estimation unit 11 also acquires the motion state of the vehicle 1 from internal data measured by the internal sensor 22.

[0021] The automated driving device 10 has an MRM function that executes a minimal risk maneuver (MRM) to slow down and stop the vehicle within the lane or move it to the shoulder if a system failure or the like occurs while the automated driving function is operating, and an emergency maneuver (EM) function that transitions to emergency avoidance control to avoid a collision if a collision with an obstacle is predicted. The automated driving device 10 further has an override function that prioritizes the override operation and transfers authority to the driver if an override operation is performed by the driver or passenger of the vehicle 1 while the automated driving function including the MRM function and EM function is operating.

[0022] The override threshold changing unit 12 is configured to set an override threshold for determining whether or not an override operation has been performed by the driver, based on information input from the environmental state estimating unit 11. Specifically, the override threshold changing unit 12 is configured to set different override threshold values when the vehicle 1 is traveling inside a roundabout and when the vehicle 1 is traveling outside the roundabout. The override threshold will be described later.

[0023] The route generation unit 13 is configured to generate a target route from the vehicle position estimated by the environmental state estimation unit 11 to a destination. The route generation unit 13 searches for a route from the departure point to the destination based on the vehicle position information and map information, and generates a rough target route, a so-called global route. Furthermore, the route generation unit 13 generates a detailed target route, a so-called local route, for autonomous driving such as lane keeping, lane changes, and course changes, based on the positions of adjacent lane markings, the positions and speeds of other vehicles, and the motion state of the vehicle estimated by the environmental state estimation unit 11. The route generation unit 13 is further configured to generate a target route for EM operation or MRM operation to a target stopping position when the vehicle 1 is stopped by activation of the EM function or MRM function.

[0024] The vehicle control unit 14 calculates a target vehicle speed and a target steering angle based on the target route generated by the route generation unit 13, and transmits a speed command for constant speed driving or vehicle-to-vehicle distance maintenance / following driving to the ACC controller 15, and transmits a steering angle command for route following to the EPS controller 31 via the automatic steering controller 16.

[0025] The vehicle speed is also input to the EPS controller 31 and the ACC controller 15. Because the steering reaction force changes depending on the vehicle speed, the EPS controller 31 refers to a steering angle-steering torque map for each vehicle speed and sends a torque command to the steering mechanism 41. The engine controller 32, the ESP / ABS controller 33, and the EPS controller 31 control the engine 42, the brakes 43, and the steering mechanism 41, thereby controlling the longitudinal and lateral movements of the vehicle 1. It is also possible to use, for example, an electric motor as a drive device for the vehicle 1 instead of or in addition to the engine 42.

[0026] [Autonomous Driving System Overview] Next, an overview of the automated driving system will be explained. The automated driving system is a system that combines an adaptive cruise control system (ACCS) with a continuous automatic steering system that automatically maintains the vehicle in its lane and changes lanes continuously. The automated driving system can execute the automated driving function when the ACC controller 15 that constitutes the adaptive cruise control system (ACCS) together with the automated driving device 10 and the automatic steering controller 16 that constitutes the continuous automatic steering system are both operating.

[0027] The driver of vehicle 1 sets a departure point and a destination before departing vehicle 1. If vehicle 1 employs a remote monitoring and remote control type autonomous driving system, the departure point and destination may be set by an operator at a remote control base station. The route generation unit 13 generates a global route from the departure point to the destination based on the vehicle position information and map information obtained from the environmental state estimation unit 11. Based on the generated global route, the route generation unit 13 generates a local route and a target vehicle speed based on external information (lanes, vehicle position, positions of other vehicles traveling in the lane in which the vehicle is traveling and adjacent lanes, speed, presence or absence of pedestrians or bicycles, etc.) acquired by external sensors 21 and internal information (vehicle speed, yaw rate, acceleration, etc.) acquired by internal sensors 22.

[0028] When the driver of vehicle 1 or the operator of the remote control base station determines that the environmental conditions, road conditions, etc. are maintained within the system's operational design domain (ODD), they send a start command to the automatic driving device 10 to make vehicle 1 travel according to the generated target route and target vehicle speed.

[0029] The vehicle control unit 14 calculates the yaw rate γ and lateral acceleration (d 2 y / dt 2 ) the speed, attitude, and lateral displacement of the vehicle 1 after Δt seconds are estimated from the relationship. The vehicle control unit 14 provides a steering angle command to the EPS controller 31 via the automatic steering controller 16 so that the lateral displacement after Δt seconds will be yt, and provides a speed command to the ACC controller 15 so that the speed will be Vt after Δt seconds.

[0030] The ACC controller 15, automatic steering controller 16, EPS controller 31, engine controller 32, and ESP / ABS controller 33 operate independently of automatic steering, but can also be operated by command input from the automatic operation device 10 while the automatic driving system is operating.

[0031] The ESP / ABS controller 33, which receives a deceleration command from the ACC controller 15, issues a hydraulic command to an actuator and controls the braking force of a brake 43, thereby controlling the vehicle speed. Furthermore, the engine controller 32, which receives an acceleration / deceleration command from the ACC controller 15, controls the actuator output (throttle opening) to issue a torque command to the engine 42, thereby controlling the driving force and thereby controlling the vehicle speed.

[0032] The ACC function (ACCS) functions as a combination of hardware and software, such as a millimeter wave radar as forward detection means 211 constituting the external sensor 21, the ACC controller 15, the engine controller 32, and the ESP / ABS controller 33.

[0033] In other words, if there is no preceding vehicle, the vehicle will travel at a constant speed with the ACC set speed (set speed) as the target vehicle speed.If the vehicle catches up with the preceding vehicle (if the preceding vehicle speed is equal to or lower than the ACC set speed), the vehicle will follow the preceding vehicle while maintaining a distance (set distance) according to the set time gap (time between vehicles = distance between vehicles / vehicle speed) in accordance with the speed of the preceding vehicle.

[0034] The continuous automatic steering system detects lane markings, the vehicle's position, and the positions and speeds of other vehicles traveling in adjacent lanes using the environmental state estimation unit 11 of the automatic operation device 10, based on image data and point cloud data acquired by external sensors 21 and vehicle information acquired by internal sensors 22. Based on this information, the continuous automatic steering system performs steering control using the EPS controller 31 via the automatic steering controller 16 to perform lane keeping control to keep the vehicle in the center of the lane and lane change control to cross lane markings.

[0035] That is, upon receiving a steering angle command from the automatic steering controller 16, the EPS controller 31 refers to a map of vehicle speed-steering angle-steering torque, issues a torque command to the actuator (EPS motor), and gives the steering mechanism 41 the target front wheel steering angle.

[0036] As described above, the autonomous driving system is a system configured by combining longitudinal control (speed control, inter-vehicle distance control) by the ACC controller 15 and lateral control (lane keeping control, lane change control) by the automatic steering controller 16.

[0037] [Emergency Avoidance Control (EM) when a collision is predicted] If another traffic participant (obstacle) enters the target route of the autonomous driving of the vehicle 1 during operation of the above-mentioned autonomous driving function, for example, due to a sudden stop of a preceding vehicle or another vehicle cutting in, and a collision with the obstacle is predicted, the emergency maneuver (EM) function is activated and emergency avoidance control is performed. The EM function includes the operation of autonomous emergency braking (AEB) to avoid a collision or mitigate damage from a collision. The EM function is configured to avoid danger by, for example, using a combination of deceleration at maximum deceleration and steering, decelerating and stopping the vehicle within its lane, or moving it to the shoulder of the road.

[0038] The environmental state estimation unit 11 calculates the predicted time to collision (TTC = vehicle distance / relative speed) to the obstacle based on information (e.g., vehicle-to-vehicle distance and relative speed) of an obstacle (e.g., a preceding vehicle) detected by the external sensor 21 and the vehicle speed of the vehicle 1 detected by the internal sensor 22. When the automatic driving device 10 determines that there is a high possibility of collision with the obstacle, such as when the predicted time to collision TTC is equal to or less than a predetermined value, it sends a deceleration request (hydraulic command) to the actuator of the brake 43 via the ACC controller 15 to activate the automatic emergency brake. Furthermore, when the automatic driving device 10 is to move the vehicle 1 to the shoulder of the road, for example, it sends a steering angle command for path tracking to the EPS controller 31 via the automatic steering controller 16.

[0039] Before and during activation of the EM function, the notification unit 17 notifies the occupants and passengers of the vehicle 1 and road users outside the vehicle. The notification unit 17 may be configured to notify those inside and outside the vehicle that the autonomous driving of the vehicle 1 has stopped. Notification methods by the notification unit 17 include visual methods such as turning on a lamp or displaying a text, and / or auditory methods such as outputting a voice.

[0040] [Risk Minimization Control (MRM) in the Event of System Failure] If, for example, a serious malfunction or failure occurs in the system while the autonomous driving function is operating, a risk minimization control (MRM) is executed to decelerate and stop the vehicle within the lane or to move it to the shoulder. Serious malfunctions or failures in the system include, for example, a drop in engine oil pressure, an increase in engine water temperature, or a brake system abnormality, which can cause an accident or fire. The autonomous driving device 10 can determine whether a serious malfunction or failure has occurred in the system, for example, by using a self-diagnosis function (not shown) of the vehicle 1.

[0041] When it is determined that a serious malfunction or failure has occurred in the system, the automatic driving device 10 activates the MRM function. The MRM function includes, for example, control to move the vehicle 1 to the shoulder of the road or to decelerate and stop the vehicle within the lane (safe stop). When activating the MRM function, the automatic driving device 10 sends a deceleration request (hydraulic pressure command) to the actuator of the brake 43 via the ACC controller 15, and also sends a steering angle command for path tracking to the EPS controller 31 via the automatic steering controller 16.

[0042] Before and during the activation of the MRM function, the notification unit 17 notifies the occupants and passengers of the vehicle 1 and road users outside the vehicle. The notification unit 17 may be configured to notify those inside and outside the vehicle that the automatic traveling of the vehicle 1 has stopped.

[0043] [Override function] The cruise control device described above is configured to enable override through operational intervention by the driver or passenger while the autonomous driving function or the EM function and MRM function are operating. In other words, the override function is a function that stops the operating function and transfers authority to the driver if the driver intervenes in an operation equal to or greater than a predetermined threshold while the autonomous driving function, EM function, or MRM function is operating.

[0044] When an acceleration override is performed by the driver's intervention in an acceleration operation or a deceleration override is performed by the driver's intervention in a deceleration operation, longitudinal control (speed control, inter-vehicle distance control) is stopped and the vehicle shifts to manual driving mode, allowing manual acceleration and deceleration operations 35, 36. When a steering override is performed by the driver's intervention in steering, lateral control (lane keeping control, lane change control) is stopped and the vehicle shifts to manual driving mode, allowing manual steering 34.

[0045] Specifically, the longitudinal control is overridden when an engine torque request made by the driver through manual accelerator pedal operation 35 or a deceleration request made by manual brake pedal operation 36 is equal to or greater than the respective override thresholds. These override thresholds for acceleration / deceleration operations (acceleration / deceleration override thresholds) are set to, for example, an accelerator operation amount (engine torque command value) or a brake operation amount (ESP hydraulic pressure command value) at which it is determined that the driver has intentionally performed an acceleration / deceleration operation, depending on the acceleration / deceleration characteristics and running state of the vehicle.

[0046] The lateral control is overridden when the steering torque due to the driver's manual steering 34 is equal to or greater than an override threshold. The override threshold for the steering operation (steering override threshold) is set, for example, according to the steering characteristics and running state of the vehicle 1. The manual steering operation 34 and manual acceleration / deceleration operations 35, 36 can be configured to be detected, for example, by the internal sensor 22.

[0047] As described above, the override function can be executed even while the EM function or MRM function is operating. Therefore, when switching from a state in which the vehicle is traveling automatically using the autonomous driving function to the EM function or MRM function, the driver may become panicked due to the notification of the operation of the EM function or MRM function or the control of the vehicle 1 due to the operation of the EM function or MRM function. If an overwhelmed driver performs an excessive override, such as excessive acceleration / deceleration or excessive steering, the behavior of the vehicle 1 may become unstable or the vehicle 1 may suddenly approach surrounding obstacles or structures.

[0048] In particular, at intersections where there is a possibility of crossing with other traffic participants, excessive override by the driver may cause contact or collision with other traffic participants or surrounding structures.

[0049] Here, a roundabout, a type of intersection, may be installed on a road. As shown in Figure 4, a roundabout is a type of intersection where multiple roads are connected via a circular space, and vehicles travel in one direction on a circular road around a central island in the center of the circular space. Generally, the circular road at a roundabout does not have stop positions or traffic lights. Furthermore, the circular road at a roundabout generally does not have shoulders or side strips, and a specified area, including the inside of the roundabout, is designated as a no-parking zone. At a roundabout, traffic on the circular road has priority. Vehicles entering the roundabout can enter the circular road at a slow speed without stopping if there are no vehicles traveling on the circular road. In this way, a roundabout differs in form from a normal crossroads or T-junction intersection.

[0050] Figure 4 shows an example of a roundabout RA where traffic rules require keeping to the left. The roundabout RA shown in Figure 4 is configured so that four roads A1 to A4 are connected and vehicles travel clockwise on a circular road C around a central island B. Pedestrian crossings D2 and D4 are installed on roads A2 and A4 of the roundabout RA, respectively. An apron F is formed between the central island B of the roundabout RA and the circular road C. Apron F is a section where large vehicles, such as semi-trailer trucks, which would have difficulty passing through the width of the circular road C alone, are permitted to partially climb onto and drive on.

[0051] When traffic rules dictate keeping to the right, vehicles travel counterclockwise on the circular road C of the roundabout RA. In the following explanation, we will use the example of keeping to the left.

[0052] For example, consider a case in which the EM function is activated when vehicle 1 enters roundabout RA from entrance E1 and is traveling on roundabout road C. Vehicle 1's own position is position 1A, and preceding vehicle 2 is about to exit roundabout RA from exit E2. If preceding vehicle 2 suddenly stops, for example, to wait for a pedestrian to cross crosswalk D2, causing the EM function to be activated, vehicle 1 will be guided, for example, along the path indicated by arrow PA, to slow down and stop. Note that the inside of roundabout RA is designated as a no-parking zone, so vehicle 1 will be guided by the EM function to leave roundabout RA and stop.

[0053] In this case, an override may be performed by the driver panicking due to the EM function activation notification or the change in the direction of travel of vehicle 1 and performing excessive driving operations. In the case of such an excessive override, it is difficult for the driver to perform appropriate collision avoidance operations through their own driving operations, and there is a risk of inducing, for example, a collision with structures surrounding the roundabout RA or other vehicles, or running off the road.

[0054] Also, assume a case in which the MRM function is activated while vehicle 1 is traveling on circular road C of roundabout RA. If a serious malfunction occurs in the system while vehicle 1 is at position 1B and the MRM function is activated, vehicle 1 will be guided out of roundabout RA from exit E4, for example, along the route indicated by arrow PB, and will stop in an evacuation area such as the shoulder of road A4. In this case, an override may be executed if the driver, panicked by the notification of the MRM function activation or the change in vehicle 1's direction of travel, performs excessive driving operations. Such an excessive override may pose a risk of inducing, for example, a collision with structures surrounding the roundabout RA or other vehicles, or running off the road.

[0055] Therefore, in the cruise control device according to this embodiment, when the vehicle 1 is traveling inside a roundabout RA that has a different configuration from normal intersections, in order to execute an override function suitable for traveling through the roundabout RA, the predetermined threshold for activating the override function is set to a value different from that when traveling outside the roundabout RA. Specifically, when the EM function or MRM function is activated while traveling inside the roundabout RA, the override threshold is changed to a value larger than that normally used outside the roundabout RA, thereby suppressing override due to excessive driving operation by the driver.

[0056] This prevents the automatic driving function, EM function, or MRM function from being overridden by excessive driving operations by the driver while traveling within the roundabout RA, and even in cases where the override function is executed by driving operations by the driver outside the roundabout RA, the automatic driving function, EM function, or MRM function by the automatic operation device 10 continues. As a result, it is possible to avoid situations where excessive acceleration / deceleration operations or excessive steering operations by the driver result in a collision with, for example, structures surrounding the roundabout RA or other vehicles.

[0057] [Override threshold settings] The setting of the override threshold in this embodiment will be described below. The override threshold, which is a predetermined threshold for driving operation used to determine whether to activate the override function, includes an acceleration / deceleration override threshold related to acceleration / deceleration operation and a steering override threshold related to steering operation. The acceleration / deceleration override threshold also includes an accelerator override threshold related to accelerator operation and a brake override threshold related to brake operation.

[0058] 1. Override threshold outside the roundabout RA (normal) During automatic driving, if the engine torque command value due to the driver's accelerator operation is greater than the engine torque command value for constant speed driving or for maintaining a vehicle distance / following driving, accelerator override is executed. In this case, the driver's accelerator operation takes priority over the automatic driving function of the automatic driving device 10. Under normal circumstances, for example, an engine torque command value determined by an engine torque map set according to the vehicle speed and gear position is set as the accelerator override threshold OE0.

[0059] During automatic driving, if an ESP hydraulic pressure command value that results in deceleration for constant speed driving or maintaining a following distance or following driving is given by the driver's brake operation, brake override is executed. In this case, the driver's brake operation takes priority over the automatic driving function of the automatic driving device 10. For example, an ESP hydraulic pressure command value that results in deceleration equivalent to a speed of 2 km / h for constant speed driving or maintaining a following distance or following driving, or a deceleration of 0.2 m / s for the ACC set acceleration, 2 An ESP hydraulic pressure command value that results in a corresponding deceleration is set as the brake override threshold value OP0.

[0060] The steering override threshold OT0 is set to a threshold for forward steering and a threshold for reverse steering. In the case of forward steering, for example, a steering torque corresponding to a steering angle at which a virtual lateral displacement y't for reaching a virtual lateral position after t seconds becomes yt+α (where α is a constant determined based on the vehicle speed) is set as the steering override threshold OT0. The steering torque corresponding to the steering angle can be calculated from a vehicle speed-steering angle-steering torque map.

[0061] In the case of countersteering, for example, a value that is applied in a direction to reduce the steering torque and that can be determined to be not small is set as the steering override threshold OT0 with respect to a value (steering torque target value) obtained by converting a steering angle such that a virtual lateral displacement y't for reaching a virtual lateral position after t seconds becomes yt+α. Whether the value is small or not can be determined based on, for example, the steering angle, the steering angular velocity, etc.

[0062] 2. Override threshold in roundabout RA During automated driving, the accelerator override threshold OEd inside the roundabout RA is set to a value greater than the accelerator override threshold OE0 outside the roundabout RA described above. That is, OEd>OE0. During automated driving, the brake override threshold OPd inside the roundabout RA is set to a value greater than the brake override threshold OPd outside the roundabout RA described above. That is, OPd>OP0.

[0063] During automated driving, the steering override threshold OTd inside the roundabout RA is set to a value greater than the steering override threshold OT0 outside the roundabout RA described above. Here, a steering override threshold (outer steering override threshold) OTdo is set for steering operations toward the outside (outer periphery) of the roundabout RA, and a steering override threshold (inner steering override threshold) OTdi is set for steering operations toward the inside (inner periphery) of the roundabout RA. That is, OTdo > OT0, Otdi > OT0. The outer steering override threshold OTdo and the inner steering override threshold OTdi may be the same value or different values. For example, the outer steering override threshold OTdo can be set to a value greater than the inner steering override threshold OTdi (OTdo > Otdi).

[0064] 3. Override threshold when MRM is activated outside the roundabout RA (outside roundabout threshold) The accelerator override threshold OEdmr when MRM is activated outside the roundabout RA is set to a value greater than the accelerator override threshold OEd inside the roundabout RA described above. That is, OEdmr>OEd. The brake override threshold OPdmr when MRM is activated outside the roundabout RA is set to a value greater than the brake override threshold OPd outside the roundabout RA described above. That is, OPdmr>OPd.

[0065] The steering override thresholds (outer steering override threshold, inner steering override threshold) OTdmr when the MRM is activated outside the roundabout RA are set to values greater than the steering override threshold OTd within the roundabout RA described above. In other words, OTdmr>OTd.

[0066] 4. Override threshold when EM is activated outside the roundabout RA (outside roundabout threshold) The accelerator override threshold OEdem when EM is activated outside the roundabout RA is set to a value greater than the accelerator override threshold OEdmr when MRM is activated outside the roundabout RA described above. That is, OEdem > OEdmr. The brake override threshold OPdem when EM is activated outside the roundabout RA is set to a value greater than the brake override threshold OPdmr when MRM is activated outside the roundabout RA described above. That is, OPdem > OPdmr.

[0067] The steering override thresholds (outer steering override threshold, inner steering override threshold) OTdem when the EM is activated outside the roundabout RA are set to values greater than the steering override threshold OTdmr when the MRM is activated outside the roundabout RA described above. In other words, OTdem>OTdmr.

[0068] 5. Override threshold when MRM is activated within a roundabout RA (threshold within the roundabout) The accelerator override threshold OEramr when MRM is activated inside a roundabout RA is set to a value greater than the accelerator override threshold OEdmr when MRM is activated outside the roundabout RA described above. That is, OEramr>OEdmr. The brake override threshold OPramr when MRM is activated inside a roundabout RA is set to a value greater than the brake override threshold OPdmr when MRM is activated outside the roundabout RA described above. That is, OPramr>OPdmr.

[0069] The steering override threshold OTramr when MRM is activated inside the roundabout RA is set to a value greater than the steering override threshold OTdmr when MRM is activated outside the roundabout RA described above. Furthermore, the outer steering override threshold OTramro for steering operations toward the outer side of the roundabout RA when MRM is activated is greater than the inner steering override threshold Oramri for steering operations toward the inner side of the roundabout RA when MRM is activated. That is, OTramro > OTramri > OTdrm.

[0070] 6. Override threshold when EM is activated within a roundabout RA (threshold within the roundabout) The accelerator override threshold OEraem when the EM is activated inside the roundabout RA is set to a value greater than the accelerator override threshold OEdem when the EM is activated outside the roundabout RA described above. In other words, OEraem > OEdem. The brake override threshold OPraem when the EM is activated inside the roundabout RA is set to a value greater than the brake override threshold OPdem when the EM is activated outside the roundabout RA described above. In other words, OPramr > OPdem.

[0071] The steering override threshold OTraem when the EM is activated inside the roundabout RA is set to a value greater than the steering override threshold OTdem when the EM is activated outside the roundabout RA described above. Furthermore, the outer steering override threshold OTraemo for steering operations toward the outer side of the roundabout RA when the EM is activated is greater than the inner steering override threshold Oraemi for steering operations toward the inner side of the roundabout RA when the EM is activated. That is, OTraemo > OTraemi > OTdem.

[0072] The relationships between the accelerator override threshold, the brake override threshold, and the steering override threshold described above are summarized below. Accelerator Override Threshold OE0 <OEd<OEdmr<OEdem OEdmr <OEramr OEdem <OEraem OEramr <OEraem Brake override threshold OP0 <OPd<OPdmr<OPdem OPdmr <OPramr OPdem <OPraem OPramr <OPraem Steering override threshold OT0 <OTd<OTdmr<OTdem OTdmr <OTramri<OTramro OTdem <OTraemi<OTraemo OTramri <OTraemi OTramro <OTraemo

[0073] The override threshold changing unit 13 sets the accelerator override threshold, brake override threshold, and steering override threshold so as to satisfy the above relationship according to the traveling conditions of the vehicle 1. The accelerator override threshold inside the roundabout RA relative to the normal accelerator override threshold (outside the roundabout RA) can be set to an engine torque command value selected from a range of, for example, 120% to 250%, preferably 150% to 220%, of the normal accelerator override threshold. Furthermore, the accelerator override threshold when the EM is activated can be selected from a range of, for example, 120% to 250%, preferably 150% to 220%, of the accelerator override threshold when the MRM is activated.

[0074] The brake override threshold inside the roundabout RA relative to the normal brake override threshold (outside the roundabout RA) can be set to an ESP hydraulic pressure command selected from the range of, for example, 120% to 250%, preferably 150% to 220% of the normal brake override threshold. Also, the brake override threshold when the EM is activated can be selected from the range of, for example, 120% to 250%, preferably 150% to 220% of the brake override threshold when the MRM is activated.

[0075] Regarding the steering override threshold within the roundabout RA, for example, in the case of a steering operation toward the inside of the roundabout RA, which is forward steering while traveling on the circular road C, the steering override threshold can be set as a value obtained by converting the steering angle calculated from the virtual lateral displacement y"t (= yt + β, where β > α) and the vehicle's motion characteristics to a steering torque, with respect to the virtual lateral displacement y't while traveling by the autonomous driving function. In the case of a steering operation toward the outside of the roundabout RA, which is reverse steering while traveling on the circular road C, the steering override threshold can be set as a value obtained by converting the steering angle calculated from the virtual lateral displacement y"t (= yt - γ, where γ is larger than the lateral displacement corresponding to the steering torque X'Nm) and the vehicle's motion characteristics, with respect to the virtual lateral displacement y't while traveling by the autonomous driving function. Furthermore, the steering override threshold when the EM is activated can be selected, for example, from a range of 120% to 250%, preferably 150% to 220%, of the steering override threshold when the MRM is activated.

[0076] [Operation flow of EM function and MRM function during autonomous driving] Next, the control flow when the EM function or MRM function is executed during automated driving will be described. Fig. 5 shows a flowchart illustrating the control flow of the EM function and MRM function according to this embodiment. Note that the automated driving device 10 is configured to monitor the possibility of a collision with an obstacle in preparation for activation of the EM function, regardless of whether the vehicle 1 is driving within a roundabout RA, and to perform self-diagnosis of the vehicle 1 system in preparation for activation of the MRM function. However, here, a case will be described in which the EM function or MRM function is activated when the vehicle 1 is driving within a roundabout RA using the automated driving function.

[0077] (1) Activation of the automatic driving function (step S100) Automated driving is performed by the automated driving device 10 in response to a start command from the driver of the vehicle 1 or an operator at a remote control base station. The automated driving device 10 controls the driving of the vehicle 1 in accordance with the generated target route and target vehicle speed. The automated driving device 10 knows that the vehicle 1 is driving within the roundabout RA based on the vehicle position information, map information, information about the shape of the roundabout RA, etc. acquired by the environmental state estimation unit 11.

[0078] (2) Determining the possibility of a collision (step S102) As described above, the environmental state estimation unit 11 determines the possibility of a collision with an obstacle around the vehicle based on information about the obstacle detected by the external sensor 21 and vehicle information about the vehicle 1 detected by the internal sensor 22.

[0079] For example, if the predicted collision time TTC to an obstacle on the target route of the vehicle 1 is equal to or less than a predetermined value, it is determined that the possibility of collision with the obstacle is high, and the process proceeds to step S110 to switch to the EM function in order to execute emergency avoidance control. If the predicted collision time TTC to the obstacle is greater than the predetermined value and it is determined that the possibility of collision is low, the process proceeds to step S104.

[0080] (3) EM function When the system transitions to the EM function, an EM activation flag is set (step S110), and activation of the EM function, including activation of automatic emergency braking to avoid a collision or mitigate collision damage, begins (step S112). The route generation unit 13 determines a target stopping position for stopping the vehicle 1 based on the position and speed of the vehicle 1 and the maximum deceleration for emergency avoidance control, and generates a target route for the EM to the determined target stopping position. The vehicle control unit 14 activates a direction indicator (not shown) in the direction of the target stopping position, and guides the vehicle 1 to the target stopping position while decelerating at the maximum deceleration according to the target route for the EM.

[0081] (4) Changing the override threshold (step S114) The override threshold changing unit 12 changes the override threshold from the override threshold within the roundabout RA (OEd, OPd, OTdo, OTdi) to the override threshold when the EM is activated within the roundabout RA (OEraem, OPraem, OTraemo, OTraemi).

[0082] (5) Override determination (step S116) The automated driving device 10 is configured to determine whether an override has occurred due to driver intervention while the automated driving function is in operation, and this determination of whether an override has occurred continues even after the EM function begins operation. If the engine torque request due to the driver's manual operation of the accelerator pedal 35, the deceleration request due to the driver's manual operation of the brake pedal 36, or the steering torque due to manual steering 34 is equal to or greater than the accelerator override threshold, brake override threshold, or steering override threshold set in step S114, it is determined that an override has occurred, and the process proceeds to step S108 to stop control by the automated driving device 10. If it is determined that an override has not occurred, the process proceeds to step S118.

[0083] (6) Roundabout RA driving judgment (S118) The automated driving device 10 determines whether the vehicle 1 is traveling outside the roundabout RA based on the vehicle position information, map information, information on the shape of the roundabout RA, etc. acquired by the environmental state estimation unit 11. If it is determined that the vehicle 1 is traveling inside the roundabout RA, the process returns to step S116 and continues traveling inside the roundabout RA using the EM function. On the other hand, if it is determined that the vehicle 1 has exited the roundabout RA and is outside the roundabout RA, the process proceeds to step S120.

[0084] (7) Changing the override threshold (step S120) The override threshold change unit 12 changes the override threshold from the override threshold when the EM is activated inside the roundabout RA (OEraem, OPraem, OTraemo, OTrarmi) to the override threshold when the EM is activated outside the roundabout RA (OEdem, OPdem, OTdem).

[0085] (8) Override determination (step S122) If the engine torque request due to the driver's manual operation of the accelerator pedal 35, the deceleration request due to the driver's manual operation of the brake pedal 36, or the steering torque due to manual steering 34 is equal to or greater than the accelerator override threshold, brake override threshold, or steering override threshold set in step S120, the automated driving device 10 determines that an override has occurred, and proceeds to step S108 to stop control by the automated driving device 10. If it is determined that an override has not occurred, the process proceeds to step S124.

[0086] (9) EM completion determination (step S124) The automated driving device 10 determines whether emergency avoidance control by the EM function has been completed based on the vehicle state and surrounding environment of the vehicle 1. Specifically, it determines that EM has been completed when the risk of an imminent collision has disappeared due to an emergency stop of the vehicle 1 or a change in the surrounding environment, or when the system is deactivated by the driver operating a switch (not shown). In this case, the accelerator override threshold, brake override threshold, or steering override threshold set in step S120 is reset to the normal override threshold, and the hazard lights are flashed. On the other hand, if it is determined that EM has not been completed, the process returns to step S122 and EM operation continues.

[0087] (10) Determining Serious Failure (Step S104) If it is determined in step S102 that there is no possibility of a collision, the environmental state estimation unit 11 determines whether or not a serious malfunction has occurred in the vehicle 1, using the self-diagnosis function of the vehicle 1. If it is determined that a serious malfunction has occurred in the vehicle 1, the process proceeds to step S130 and transitions to the MRM function. If it is determined that no serious malfunction has occurred, the process proceeds to step S106.

[0088] (11) MRM function When the MRM function is activated, a flag for MRM activation is set (step S130), and operation of risk minimization control (MRM) begins, which decelerates and stops the vehicle within the lane or moves the vehicle to the shoulder. The route generation unit 13 determines a target stopping position for stopping the vehicle 1 based on the position and speed of the vehicle 1 and a predetermined deceleration for MRM, and generates a target route for MRM to the determined target stopping position. The vehicle control unit 14 guides the vehicle 1 to the target stopping position while decelerating at a predetermined deceleration according to the target route for MRM. While the MRM function is activated, the hazard lights (not shown) are flashed.

[0089] (12) Change the override threshold (step S134) The override threshold change unit 12 changes the override threshold from the override threshold within the roundabout RA (OEd, OPd, OTdo, OTdi) to the override threshold when MRM is activated within the roundabout RA described above (OEramr, OPramr, OTramro, OTramri).

[0090] (13) Override Determination (Step S136) The automated driving device 10 is configured to determine whether an override has occurred due to driver intervention while the automated driving function is in operation, and this determination of whether an override has occurred continues even after the MRM function begins operation. If the engine torque request due to the driver's manual operation of the accelerator pedal 35, the deceleration request due to manual operation of the brake pedal 36, or the steering torque due to manual steering 34 is equal to or greater than the accelerator override threshold, brake override threshold, or steering override threshold set in step S134, it is determined that an override has occurred, and the process proceeds to step S108 to stop control by the automated driving device 10. If it is determined that an override has not occurred, the process proceeds to step S138.

[0091] (14) Roundabout RA Driving Judgment (S138) The automated driving device 10 determines whether the vehicle 1 is traveling outside the roundabout RA based on the vehicle position information, map information, information on the shape of the roundabout RA, etc. acquired by the environmental state estimation unit 11. If it is determined that the vehicle 1 is traveling inside the roundabout RA, the process returns to step S136 and continues traveling inside the roundabout RA using the MRM function. On the other hand, if it is determined that the vehicle 1 has exited the roundabout RA and is outside the roundabout RA, the process proceeds to step S140.

[0092] (15) Change the override threshold (step S140) The override threshold change unit 12 changes the override threshold from the override threshold when MRM is activated inside the roundabout RA (OEramr, OPramr, OTramro, OTramri) to the override threshold when MRM is activated outside the roundabout RA (OEdmr, OPdmr, OTdmr).

[0093] (16) Override Determination (Step S142) If the engine torque request due to the driver's manual operation of the accelerator pedal 35, the deceleration request due to the driver's manual operation of the brake pedal 36, or the steering torque due to manual steering 34 is equal to or greater than the accelerator override threshold, brake override threshold, or steering override threshold set in step S140, the automated driving device 10 determines that an override has occurred, and proceeds to step S108 to stop control by the automated driving device 10. If it is determined that an override has not occurred, the process proceeds to step S144.

[0094] (17) MRM Completion Determination (Step S144) The automated driving device 10 determines whether control by the MRM function has been completed based on the vehicle state and surrounding environment of the vehicle 1. Specifically, it is determined that MRM has been completed when the vehicle 1 is guided out of the roundabout RA and stopped by the MRM function, or when the system is deactivated by the driver operating a switch (not shown). In this case, the accelerator override threshold, brake override threshold, or steering override threshold set in step S140 is reset to the normal override threshold. On the other hand, if it is determined that MRM has not been completed, the process returns to step S142 and MRM operation continues.

[0095] (18) Autonomous driving function continuation determination (S106) If it is determined in step S104 that there is no serious malfunction of the vehicle 1, the automatic operation device 10 determines whether to continue the automatic driving function of the vehicle 1. Specifically, it determines whether the driving state of the vehicle 1 and the surrounding environmental conditions acquired by the environmental state estimation unit 11 are maintained within the operation design domain (ODD) of the system. For example, if a strong wind exceeding a tolerable value is blowing, it is determined that the vehicle is outside the ODD. In addition, the self-diagnosis function determines whether a malfunction or abnormality other than the serious malfunction described above has occurred in the vehicle 1. For example, if the external sensor 21 is malfunctioning, it is determined that another malfunction or abnormality has occurred. If it is determined that there is an ODD deviation or another malfunction or abnormality, or if the system is deactivated by the driver operating a switch (not shown), the process proceeds to step S108 to stop the automatic driving function. On the other hand, if it is determined that the ODD is maintained and there are no other malfunctions or abnormalities, the process returns to step S102 to continue the automatic driving function.

[0096] (19) Automatic driving function deactivation (S108) If it is determined in step S116, S122, S136 or S142 that an override has been made due to driver intervention, if it is determined in step S124 that EM has been completed, if it is determined in step S144 that MRM has been completed, or if it is determined in step S106 that the automatic driving function should be stopped, the automatic driving function of the automatic operation device 10 is stopped and the system transitions to manual driving mode.

[0097] The cruise control device for the vehicle 1 according to the first embodiment described above can achieve the following advantageous effects.

[0098] (1) A driving control device for a vehicle equipped with an automatic operation device 10 for executing an automatic driving function has an MRM function that performs risk minimization control, including decelerating and stopping the vehicle 1 within its lane, if a system failure occurs while the automatic driving function is operating, an EM function that performs emergency avoidance control, including activating the emergency brake, if a collision with an obstacle around the vehicle 1 is predicted while the automatic driving function is operating, and an override function that stops the operating function and transfers authority to the driver if the driver intervenes in an operation equal to or greater than a predetermined threshold while the automatic driving function, MRM function, or EM function is operating. The override function is configured to set different predetermined thresholds for activating the override function when the vehicle 1 is traveling inside a roundabout RA and when it is traveling outside the roundabout RA.

[0099] Like normal intersections and T-junctions, roundabouts RA pose a risk of crossing with other traffic participants. However, because the roundabout RA has a different configuration from normal intersections and T-junctions, it is desirable to execute an override function that is appropriate for driving at the roundabout RA. For example, because there are no shoulders or shoulder strips on the outer periphery of the roundabout RA, excessive override could result in contact or collision between vehicle 1 and surrounding structures outside the roundabout RA, such as guardrails. Furthermore, if excessive override causes vehicle 1 to run over a step on the apron F inside the roundabout RA, the behavior of vehicle 1 could become unstable. Therefore, by setting different override thresholds for determining whether to override the automated driving function, MRM function, or EM function when driving inside the roundabout RA and when driving outside the roundabout RA, it is possible to set an override threshold that is appropriate for driving at the roundabout RA.

[0100] (2) The override function is configured such that when the MRM function or the EM function is operating outside the roundabout RA, the outside roundabout threshold is set as the predetermined threshold, and when the MRM function or the EM function is operating inside the roundabout, the inside roundabout threshold is set as the predetermined threshold, and the inside roundabout threshold is greater than the outside roundabout threshold.

[0101] Because roundabouts RA are typically designated as no-parking zones, even if the MRM or EM function is activated within the roundabout RA, it is necessary to safely move vehicle 1 out of the roundabout RA. However, if the driver panics when the MRM or EM function changes the direction of travel of vehicle 1 and performs excessive driving maneuvers, causing an override to be executed, there is a risk of vehicle 1 coming into contact with or colliding with structures surrounding the roundabout RA or other traffic participants. Furthermore, in an emergency situation in which the MRM or EM function is activated, it is extremely difficult for the driver to perform appropriate driving maneuvers within the roundabout RA, where parking and stopping are prohibited. Therefore, by making the inside-roundabout threshold higher than the outside-roundabout threshold and making it more difficult for the override function to be executed within the roundabout RA, the automated driving device 10 can continue to use the MRM or EM function to safely avoid emergencies.

[0102] (3) The override function includes, as a predetermined threshold, a steering override threshold for activating the override function when the driver intervenes in steering while the MRM function or the EM function is operating. The steering override threshold includes an outer steering override threshold (OTramro, OTraemo) for steering to the outside of the roundabout RA within the roundabout RA, and an inner steering override threshold (OTramri, OTraemi) for steering to the inside of the roundabout RA within the roundabout RA, and the outer steering override threshold (OTramro, OTraemo) is greater than the inner steering override threshold (OTramri, OTraemi).

[0103] As described above, there are no shoulders or roadsides on the outer periphery of the roundabout RA, and the distance between the vehicle 1 traveling on the circular road C and surrounding structures such as guardrails is short. Therefore, by making the outer steering override thresholds (OTramro, OTraemo) larger than the inner steering override thresholds (OTramri, OTraemi), it becomes difficult for the MRM function or EM function to be overridden by steering operations toward the outer periphery of the roundabout RA. This prevents contact or collision between the vehicle 1 and surrounding structures on the outside of the roundabout RA, and allows the vehicle 1 to safely evacuate using the MRM function or EM function of the automated driving device 10.

[0104] (4) When the MRM function or EM function is activated within the roundabout RA and the MRM function or EM function causes the vehicle 1 to move out of the roundabout RA, the override function is configured to change from the inside-roundabout threshold value when the MRM function or EM function is activated to the outside-roundabout threshold value when the MRM function or EM function is activated. This makes it possible to set an override threshold value that is appropriate for the driving conditions of the vehicle 1.

[0105] -Second embodiment- A vehicle cruise control device according to a second embodiment of the present invention will be described below. The basic configuration of the vehicle cruise control device according to the second embodiment is the same as that of the first embodiment described above. The following mainly describes the differences from the first embodiment.

[0106] In this embodiment, the override threshold is set in more detail depending on the structure of the roundabout RA.

[0107] (1) Apron structure As shown in Figure 4, an apron F is provided between the central island B of the roundabout RA and the circular road C. Apron F is a section where large vehicles, such as semi-trailer trucks, that would have difficulty passing through the width of the circular road C alone are permitted to run partially onto it. At the boundary between the circular road C and the apron F, steps or rumble strips, for example, are provided to distinguish the circular road C from the apron F. Rumble strips are successive depressions formed in the pavement of the road. Alternatively, some roundabouts RA visually distinguish the circular road C from the apron F by drawing diagonal lines or the like on the road. As such, the apron F of a roundabout RA can have a variety of structures.

[0108] If the EM or MRM function is activated while the vehicle 1 is traveling through a roundabout RA and the driver performs a steering operation toward the inside of the roundabout RA (toward the inner perimeter), thereby overriding the EM or MRM function, the vehicle 1 will move in a direction approaching the central island B of the roundabout RA. In this case, if the apron F has a structure with a step, the vehicle 1 may climb over the step and the behavior of the vehicle 1 may become unstable.

[0109] Therefore, in this embodiment, the inside steering override threshold while traveling within the roundabout RA is changed depending on the apron structure of the roundabout RA. Specifically, the inside steering override threshold when there is a step between the apron F of the roundabout RA and the circular road C is set to a value greater than the inside steering override threshold when there is no step.

[0110] Specifically, with regard to the inside steering override threshold OTraemi for steering operations toward the inside of the roundabout RA when EM is activated, the inside steering override threshold OTraemi_1 when there is a step between the apron F and the circular road C is set to a value greater than the inside steering override threshold OTraemi_0 when there is no step. Also, with regard to the inside steering override threshold OTramri for steering operations toward the inside of the roundabout RA when MRM is activated, the inside steering override threshold OTramri_1 when there is a step between the apron F and the circular road C is set to a value greater than the inside steering override threshold OTramri_0 when there is no step.

[0111] As a result, if there is a step between the apron F of the roundabout RA and the circular road C, the EM function or MRM function is less likely to be overridden even if the vehicle is steered toward the inside of the roundabout RA. As a result, it is possible to suppress unstable behavior of the vehicle 1, such as the vehicle 1 running over the step between the apron F and the circular road C due to excessive steering by the driver.

[0112] The structure of the apron F of the roundabout RA can be determined, for example, from information about the shape of the roundabout RA acquired from the map information database 23, or image data acquired from the external sensor 21, or the like.

[0113] (2) Presence or absence of a pedestrian crossing As shown in Figure 4, a road extending from the exit of a roundabout RA may have a crosswalk. For example, if a crosswalk D4 is installed, as in the case of road A4 shown in Figure 4, there is a possibility that a pedestrian may be crossing the crosswalk D4. Therefore, when vehicle 1 is approaching the exit of a roundabout RA and a crosswalk is installed beyond the exit, the outside steering override threshold is increased to a larger value.

[0114] Specifically, for example, when the vehicle 1 is approaching an exit E4 where a crosswalk D4 is installed, the outer steering override threshold for steering operations toward the outside of the roundabout RA when the EM is activated is changed to a value OTraemo_1 that is larger than the outer steering override threshold OTraemo for steering operations toward the outside of the roundabout RA when the EM is activated described above. On the other hand, when the vehicle 1 is approaching an exit E3 of the roundabout RA, for example, there is no crosswalk beyond the exit E3, so the outer steering override threshold for EM activation is changed to a value OTraemo_0 that is smaller than the outer steering override threshold OTraemo for EM activation described above. However, the outer steering override threshold OTraemo_0 after the change is equal to or larger than the inner steering override threshold OTraemo of the roundabout RA when the EM is activated. That is, OTraemo_1 > OTraemo > OTraemo_0 ≧ OTraemi.

[0115] Furthermore, for example, when the vehicle 1 is approaching an exit E4 where a pedestrian crossing D4 is installed, the outer steering override threshold for steering operations toward the outside of the roundabout RA when the MRM is activated is changed to a value OTramro_1 that is larger than the outer steering override threshold OTramro for steering operations toward the outside of the roundabout RA when the MRM is activated described above. On the other hand, when the vehicle 1 is approaching an exit E3 of the roundabout RA, for example, there is no pedestrian crossing beyond the exit E3, so the outer steering override threshold for steering operations toward the outside of the roundabout RA when the MRM is activated is changed to a value OTramro_0 that is smaller than the outer steering override threshold OTramro for steering operations toward the outside of the roundabout RA when the MRM is activated described above. However, the outer steering override threshold OTramro_0 after the change is equal to or larger than the inner steering override threshold OTramri of the roundabout RA when the MRM is activated. That is, OTramro_1 > OTramro > OTramro_1 ≧ OTramri.

[0116] As a result, when a pedestrian crossing is installed beyond the exit of the roundabout RA, the EM function or MRM function is less likely to be overridden even if the vehicle is steered toward the outside of the roundabout RA. As a result, the MRM function or EM function by the automated driving device 10 can be continued, making it possible to avoid contact or collision with a crossing pedestrian.

[0117] Because there are no surrounding structures such as guardrails at the exit of the roundabout RA, there is little risk of the vehicle 1 coming into contact with or colliding with surrounding structures even if the override function is activated by steering toward the outside of the roundabout RA. Therefore, if there is no crosswalk beyond the exit, the risk of coming into contact with or colliding with a crossing pedestrian is low, so the driver's driving intention can be prioritized by reducing the outside steering override threshold for steering toward the outside of the roundabout RA.

[0118] Whether or not a crosswalk is installed on a road connected to the roundabout RA can be determined, for example, from information about the roundabout RA obtained from the map information database 23, or image data obtained from the external sensor 21.

[0119] -Variations- (1) In the above-described embodiment, whether the vehicle 1 is traveling within the roundabout RA is determined based on the vehicle position information, map information, information about the shape of the roundabout RA, and the like acquired by the environmental state estimation unit 11. However, for example, if a malfunction occurs in the position detection unit for detecting the current position of the vehicle 1, which is configured with the camera 212 included in the external sensor 21 or the positioning means 24 such as GNSS, it may not be possible to accurately determine whether the vehicle 1 is traveling within the roundabout RA. In this case, whether the vehicle 1 is within the roundabout RA can be determined taking into account the shape of the roundabout RA, in which it is necessary to steer toward the outside of the roundabout RA in order to exit the roundabout RA.

[0120] As shown in FIG. 4, in the case of left-hand driving, vehicle 1 drives around circular road C clockwise, and when exiting roundabout RA, it steers left and exits from one of the exits. That is, while driving around circular road C, vehicle 1 is steered right, and when exiting roundabout RA, vehicle 1 is steered in a direction different from the right steering for driving around. Therefore, when the steering angle of vehicle 1 continues for a predetermined time or more and is controlled in a direction different from the steering direction for vehicle 1 traveling along circular road C of roundabout RA, it can be determined that vehicle 1 has moved out of roundabout RA. The steering angle of vehicle 1 can be detected by, for example, internal sensor 22.

[0121] The override threshold change unit 12 is configured to change the override threshold from the inside-roundabout threshold to the outside-roundabout threshold when it is determined that the vehicle 1 has moved out of the roundabout RA as described above.

[0122] (2) In the above-described embodiment, when the EM function is activated, the vehicle 1 is guided to the outside of the roundabout RA and decelerated to a stop. However, this is not limited to this, and the vehicle 1 may be configured to be stopped within the roundabout RA depending on the shape of the roundabout RA or the situation when the EM function is activated.

[0123] (3) In the above-described embodiment, an example has been described in which the automatic operation device 10 has both the EM function and the MRM function. However, this is not limited to this, and even if the automatic operation device 10 has either the EM function or the MRM function, the override threshold can be set as described above.

[0124] Although several embodiments of the present invention have been described above, it should be noted that the present invention is not limited to the above-described embodiments, and various modifications and variations are possible within the scope of the present invention. [Explanation of symbols]

[0125] 1 vehicle 10 Automatic operation device 11 Environmental state estimation unit 12 Override threshold change section 13 Route generation unit 14 Vehicle control unit 15 ACC controller 16 Autopilot Controller 21 External Sensor 22 Internal Sensors 23 Map Information Database 24 Positioning Method (GNSS) 31 EPS controller 32 Engine Controller 33 ESP / ABS controller 34 Manual steering (steering wheel) 35 Manual operation (accelerator pedal) 36 Manual operation (brake pedal)

Claims

1. A driving control device for a vehicle equipped with an automatic driving device for executing an automatic driving function, an MRM function that executes risk minimization control, including decelerating and stopping the vehicle within its lane, when a system failure occurs during operation of the autonomous driving function; an EM function that executes emergency avoidance control, including activation of an emergency brake, when a collision with an obstacle present around the vehicle is predicted during operation of the automatic driving function; an override function that stops the function in operation and transfers authority to the driver when the driver intervenes in an operation equal to or greater than a predetermined threshold while the automatic driving function, the MRM function, or the EM function is in operation; In those having The override function is configured to set the predetermined threshold for activating the override function to different values when the vehicle is traveling inside a roundabout and when the vehicle is traveling outside the roundabout.

2. the override function is configured such that, when the MRM function or the EM function is operating outside the roundabout, an outside-roundabout threshold value is set as the predetermined threshold value, and when the MRM function or the EM function is operating inside the roundabout, an inside-roundabout threshold value is set as the predetermined threshold value; The vehicle cruise control device according to claim 1 , wherein the inside-roundabout threshold is greater than the outside-roundabout threshold.

3. the override function includes, as the predetermined threshold, a steering override threshold for activating the override function when the driver intervenes in steering while the MRM function or the EM function is in operation, 3. The vehicle driving control device according to claim 2, wherein the steering override threshold includes an outer steering override threshold when steering to the outside of the roundabout within the roundabout, and an inner steering override threshold when steering to the inside of the roundabout within the roundabout, and the outer steering override threshold is greater than the inner steering override threshold.

4. the override function is configured to vary the inside steering override threshold within the roundabout in response to an apron configuration of the roundabout; 4. The vehicle driving control device according to claim 3, wherein the inside steering override threshold when there is a step between the apron of the roundabout and the circular road is set to a value greater than the inside steering override threshold when there is no step.

5. 4. The vehicle driving control device according to claim 3, wherein the override function is configured to change the outside steering override threshold to a larger value when the vehicle is approaching an exit of the roundabout and a pedestrian crossing is installed beyond the exit of the roundabout.

6. 4. The vehicle driving control device according to claim 3, wherein the override function is configured to change the outer steering override threshold to a smaller value when the vehicle is approaching an exit of the roundabout and there is no pedestrian crossing beyond the exit, and the outer steering override threshold after the change is equal to or greater than the inner steering override threshold.

7. 7. The vehicle driving control device according to claim 2, wherein when the MRM function or the EM function is activated within the roundabout and the MRM function or the EM function causes the vehicle to move out of the roundabout, the override function is configured to change from the inside-roundabout threshold value at the time the MRM function or the EM function is activated to the outside-roundabout threshold value at the time the MRM function or the EM function is activated.

8. 8. The vehicle driving control device according to claim 7, wherein if a malfunction occurs in a position detection unit for detecting the current position of the vehicle while the MRM function or the EM function is operating within the roundabout, the override function is configured to determine that the vehicle has moved outside the roundabout when the steering angle of the vehicle continues for a predetermined time or more and is controlled in a direction different from the steering direction for the vehicle to travel along the circular road of the roundabout, and to change the threshold value from the inside roundabout threshold to the outside roundabout threshold.

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