DRIVE CONTROL DEVICE FOR A VEHICLE

Abstract

A driving control device (10) for a vehicle (1), comprising: an environmental condition estimating part (11) comprising an environmental recognition function (21) for recognizing a lane of the vehicle (1) and neighboring lanes and other vehicles in the respective lanes, a function (22) for obtaining the moving state of the vehicle (1), and a communication function (16) for obtaining information about other vehicles in a lane being merged into; a route generation part (12) for generating a target route based on information obtained from the environmental condition estimating part (11);anda vehicle control part (13) for performing acceleration / deceleration control and steering control to cause the vehicle (1) to follow the target route, and comprising:a function for generating a target route to a predetermined area as a destination and for performing an automated lane change to an adjacent lane when no other vehicle is detected by the surroundings detection function (11, 21) in the predetermined area of the adjacent lane; anda merging assist function for generating a target route using the information about other vehicles obtained from the communication function (16), for performing acceleration / deceleration control and steering control, and for automatically merging into the lane into which merging is being carried out;characterized in that the driving control device (10) has a function which changes override threshold values (Pd, Td, T1d, T2d), which serve as a determination criterion for an operator intervention to terminate the acceleration / deceleration control and the steering control, to a value (Po, To, T1o, T2o) which is higher than during the normal operation of the communication function (16) when an error occurs in the communication function (16) during automatic merging;

Description

[Field of Technology]The present invention relates to a driving control device for a vehicle, and more particularly to a semi-automated lane change system and an automated merging system using road-to-vehicle communication.[Prior Art]A variety of techniques for reducing the burden on drivers and assisting safe driving, for example, adaptive cruise control systems (= ACCS) and lane keeping assistance systems (lane keeping assistance systems = LKAS), have been put into practical use. Further, the practical application and international standardization of a partially automated in-lane driving system (PADS) based on these technologies, a partially automated lane change system (PALS) and an automated merging system using road-to-vehicle communication are currently being advanced.Such a driving control system is only for the purpose of assisting driving, and is different from fully automatic driving. A driver must leave the hands on the steering wheel and track the driving situation in order to be able to drive manually at any time, he must react according to the situation, and the driving control system has an override function which switches over to manual driving even during operation of the system by an operating intervention of the driver. JP 2012-96 569 A discloses a device for controlling lateral movement of a vehicle that determines a change speed (fallback speed [fallback speed]) of a fallback control variable for switching to manual driving depending on the change speed of a steering operation variable [fallback control mount] input by a driver.US 2017 / 0 240 172 A1 describes a lane change control that determines whether or not lane change is possible based on a detection result of an obstacle by a radar and an obstacle detection device in response to detection of a direction indicator operation by an operation detection unit. Lane keeping control continues lane keeping control when the operation detection unit detects the turn signal operation during the lane keeping control and when the lane changing control determines that the lane change is impossible.[Summary of the Invention][Problems to be Solved by the Invention]When a speed change of the steering operation amount is large, it is considered as a driver's intended steering intervention in JP 2012-96 569 A, and the driving is switched to manual driving in a short period of time, and when the speed change of the steering operation amount is small, fallback control is performed over a comparatively longer period of time, and the driving is switched to manual driving. However, the large speed change of the steering operation amount does not necessarily mean a steering intervention intended by the driver, nor does a fallback control corresponding to the speed change of the steering operation amount necessarily mean a control suitable for the state of motion of the vehicle.For example, when the road-to-vehicle communication is interrupted due to a failure of a road-to-vehicle communicator or a communication failure during merging assistance in an automated merging system in which road-to-vehicle communication is used, the automated merging system attempts to continue automated merging (automated lane change) by sensor information of the vehicle itself, but when it cannot continue automated merging by the sensor information due to movement of other vehicles or the like, the driver is notified of the advance notice of the completion of the automated lane change function and the operation takeover request, and fallback control of the automated lane change function is started after elapse of several seconds.When the driver is informed of the occurrence of a communication failure, the completion of the automated merging, and the operation takeover request, when a switch to manual driving due to an override by an excessive steering operation or an override by an excessive operation of the brake pedal / accelerator pedal by a driver who is requested from the notification, the vehicle may approach a following vehicle or approach a vehicle in a neighboring lane due to a lane departure.The present invention has been made in view of the above-described actual situation, and an object of the invention is to avoid lane departure and approaching to other vehicles due to excessive operation intervention at the time of occurrence of a communication failure during merging assistance using the road-to-vehicle communication.[Means for Solving Problems]In order to solve the above-described problems, the present invention is a travel control device for a vehicle, comprising: an environment state estimating part including an environment recognition function for recognizing a vehicle's own lane and adjacent lanes and other vehicles in the respective lanes, a function for obtaining the moving state of the vehicle, and a communication function for obtaining information about other vehicles in a threaded lane; a route generating part for generating a target route based on information obtained from the environment state estimating part; and a vehicle control part for performing acceleration-deceleration control and steering control for causing the vehicle to follow the target route, and having:a function for creating a target route to a predetermined area as a target and performing an automated lane change to a neighboring lane when no other vehicle is recognized by the surrounding environment recognition function in the predetermined area of the neighboring lane; anda merging assisting function for creating a target route using information on other vehicles obtained from the communication function, performing acceleration / deceleration control and steering control, and automatically merging into the lane to be merged;characterized in that the travel control device has a function that changes oversteer thresholds serving as a determination criterion for an operation intervention for ending the acceleration / deceleration control and the steering control to a value higher than during the normal operation of the communication function when a failure occurs in the communication function during the automatic merging.[Advantageous Effects of the Invention]According to the travel control device for a vehicle according to the present invention, because the override threshold value serving as a determination criterion of an operation intervention related to steering and braking / driving is changed to a value higher than normal operation of the communication function, when a failure occurs in the communication function during the automated merging when a driver who is required of the notice of completion of the automated merging and the operation intervention due to the occurrence of the communication failure performs an excessive operation intervention, override can be avoided, enabling the switching to the fallback control of the merging support function (automated lane change function), acceleration / deceleration, Therefore, it is possible to prevent lane departure and the like due to excessive operation intervention, and this is advantageous for smooth operation intervention.[Brief Description of Drawings]FIG. 1 is a schematic view illustrating a driving control system of a vehicle. FIG. 2 is a schematic plan view illustrating an external sensor group of the vehicle. FIG. 3 is a block diagram showing the driving control system of the vehicle. FIG. 4 is a flowchart illustrating control for avoiding oversteer due to excessive operation intervention at the time of occurrence of a communication failure during merging assistance by road-to-vehicle communication. FIG. 5 : 5A is a schematic plan view illustrating merging assistance by road-to-vehicle communication, and FIG. 5B is a schematic plan view illustrating excessive operation / steering override at the time of occurrence of communication failure during merging assistance and control for avoiding it.[Embodiment of Invention]Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.In FIG. 1, a vehicle 1 equipped with a driving control system according to the present invention includes, in addition to general components of an automobile such as an engine and a vehicle body, an external sensor 21 for detecting an environment surrounding the vehicle, an internal sensor 22 for detecting vehicle information, a controller / actuator group for speed control and steering control, an ACC controller 14 for controlling inter-vehicle distance, an LKA controller 15 for lane keeping assist control, and an automated driving controller 10 for controlling them, performing route following control, and performing semi-automated lane keeping (PAD) driving, automated lane change (PALS), and automated merging described below, for performing recognition, determination, and operation on the vehicle side, which are conventionally performed by a driver.The control unit / actuator group for speed control and steering control includes an EPS (Electric Power Steering) control unit 31 for steering control, a motor control unit 32 for acceleration / deceleration control, and an ESP / ABS control unit 33.The external sensor 21 is composed of a plurality of detection means for inputting lane markings on a road defining the own-vehicle lane and the adjacent lane and the presence and relative distance of other vehicles, obstacles and persons and the like around the vehicle into the automated driving control apparatus 10 as image data or point cloud data.For example, as illustrated in FIG. 2, the vehicle 1 includes a millimeter wave radar ( 211) and a camera ( 212) as front detection means 211 and 212, LIDARs (laser image detection and ranging) as front lateral detection means 213 and rear lateral detection means 214, and a camera (rear camera) as rear detection means 215, whereby 360° around the vehicle can be covered and positions and distances of vehicles, obstacles, and the like, and the positions of lane markings within a predetermined distance from the vehicle in the front, rear, left, and right directions can be detected.The internal sensor 22 is composed of a plurality of detection means, such as a vehicle speed sensor, a yaw rate sensor, and an acceleration sensor, for measuring physical quantities representing the state of motion of the vehicle, and their measurement values are input to the automated driving controller 10, the ACC controller 14, the LKA controller 15, and the EPS controller 31, as illustrated in FIG. 3.The automated driving control apparatus 10 includes an environmental state estimating part 11, a route generating part 12, and a vehicle control part 13, and includes a computer for executing functions described below, i.e., a ROM storing programs and data, a CPU for performing arithmetic processing, a RAM for reading out the programs and the data and storing dynamic data and results of the arithmetic processing, an input / output interface, and the like.The surrounding state estimating part 11 acquires the vehicle's absolute own position by matching the vehicle's own position information with positioning means 24 such as GPS and map information, and determines positions of lane markings of the vehicle's own lane and the adjacent lane and positions and speeds of other vehicles based on external data such as image data and point cloud data obtained by the external sensor 21. Moreover, it acquires the own-vehicle motion state from internal data measured by the internal sensor 22.The route generation part 12 generates a target route to an arrival target from the own-vehicle position estimated by the surrounding state estimation part 11. It refers to map information 23, and generates a target route from the own-vehicle position to a lane-change arrival target point based on the positions of the lane markings of the adjacent lane, the positions and speeds of other vehicles, and the moving state of the vehicle itself estimated by the surrounding state estimating part 11.The vehicle control part 13 calculates a target speed and a target steering angle based on the target route generated by the route generation part 12, sends a speed command for constant speed travel or constant-speed travel while maintaining the inter-vehicle distance / following travel to the ACC controller 14, and sends a steering angle command for following the route to the EPS controller 31 via the LKA controller 15.The vehicle speed is also input to the EPS controller 31 and the ACC controller 14. Because the steering torque changes with 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 a steering 41. the engine controller 32, the ESP / ABS controller 33, and the EPS controller 31 control a motor 42, a brake 43, and the steering 41, and thereby control the movement of the vehicle 1 in the longitudinal direction and the lateral direction.(Overview of a Partially Automated Lane Keeping Driving System and a Partially Automated Lane Changing System)Next, an overview of a partially automated lane keeping driving system (PADS) and a partially automated lane changing system (PALS) based on the assumption of traveling on an expressway will be explained.The partially automated lane keeping (PADS) drive is activated in a state in which both the ACC controller 14 included in the ACCS and the LKA controller 15 included in the LKAS are operated together with the automated driving controller 10.During the operation of the semi-automated lane keeping driving system, the automated driving controller 10 (route generation part 12) generates a target route within a single lane and a target speed based on external information (lanes, vehicle position, and positions and speeds of other vehicles traveling in the lane and the adjacent lane) obtained from the surrounding state estimation part 11 through the external sensor 21 and internal information (vehicle speed, yaw rate, and acceleration) obtained through the internal sensor 22.The automated driving controller 10 (vehicle control part 13) estimates the speed, posture, and lateral displacement of the vehicle after Δt seconds from a relationship of the yaw rate γ and lateral acceleration (d 2 y / dt 2), which are generated by the movement of the vehicle, the own-vehicle position, and the own-vehicle movement characteristics, that is, a front wheel steering angle δ which is present when a steering torque T is applied to the steering 41 during driving at a vehicle speed V, and outputs a steering angle command which causes the lateral displacement after Δt seconds to be yt to the EPS controller 31 via the LKA controller 15, and outputs a speed command which causes, the speed after Δt seconds is Vt to the ACC controller 14.Although the ACC controller 14, the LKA controller 15, the EPS controller 31, the engine controller 32, and the ESP / ABS controller 33 operate independently of the automated steering, they are operable for the automated driving during the operation of the partially automated lane keeping driving system (PADS) and the partially automated lane changing system (PALS), but also by a command input from the automated driving controller 10.The ESP / ABS controller 33, upon receiving a deceleration command from the ACC controller 14, outputs a hydraulic command to an actuator and controls the braking force of a brake 43, thereby controlling the vehicle speed. Moreover, an engine controller 32 that has received an acceleration / deceleration command from the ACC controller 14 controls an actuator output (degree of throttle opening), whereby the engine 42 receives a torque command and controls the driving force for controlling the vehicle speed.The ACC function (ACCS) functions with a combination of hardware and software such as the millimeter wave radar as front detection means 211 integrated with the external sensor 21, the ACC controller 14, the engine controller 32, and the ESP / ABS controller 33.That is, when no vehicle is running ahead, the ACC function performs constant-speed running by setting a speed set at the cruise control as a target speed; and when a preceding vehicle has been obtained (when the speed of the preceding vehicle is lower than the speed set at the cruise control), the ACC performs running following the preceding vehicle by maintaining a vehicle distance set according to the speed of the preceding vehicle as a time distance (time to the preceding vehicle=space to the preceding vehicle / vehicle speed).The LKA function (LKAS) determines lane markings and the own-vehicle position by the surrounding state estimating part 11 of the automated driving control apparatus 10 based on image data obtained from the external sensor 21 (cameras 212 and 215), and performs steering control by the LKA control apparatus 15 and the EPS control apparatus 31 to enable running in the center of the lane.That is, the EPS controller 31 that has received the steering angle command from the LKA controller 15 refers to a vehicle speed-steering angle-steering torque map, outputs a torque command to an actuator (EPS motor), and outputs a front wheel steering angle targeted by the steering 41.The semi-automatic lane keeping driving (PADS) function is implemented by a combination of the longitudinal control (speed control and inter-vehicle distance control) by the ACC controller 14 and the lateral control (steering control and lane keeping control) by the LKA controller 15 as described above.The semi-automated lane change system (PALS) is a system that automatically makes a lane change by an instruction or consent of the driver, and is implemented by combining the longitudinal control (speed control and inter-vehicle distance control) by the ACC controller 14 and the lateral control (target route following control by automatic steering) by the LKA controller 15 in the same manner as the semi-automated driving (PADS driving).When the lane change system is active, the automated driving controller 10 (route generation part 12) constantly generates a target route for changing the driving lane from the driving lane currently being driven to a neighboring lane based on the external information (lane markings of the own-vehicle lane and the neighboring lane and positions and speeds of other vehicles traveling in the own-vehicle lane and the neighboring lane, and the speed) obtained from the surrounding state estimation part 11 by the external sensor 21 and the internal information (vehicle speed, yaw rate, and acceleration) obtained by the internal sensor 22.The target route of the automated lane change is a route that leads from the currently traveling lane to a state of traveling in the center of the adjacent lane by a change in the lane; the future positions and speeds of other vehicles traveling on the adjacent lane are predicted, and automated lane change to the adjacent lane by automatic steering is performed when it is determined that no other vehicle is in a predetermined range of the adjacent lane set as a function of the speed of the vehicle, and lane change is instructed by a blinking operation of the driver, system determination, or the like.(Outline of Automated Threading System Using Road-to-Vehicle Communication)Next, an overview of an automated merging system using road-to-vehicle communication on the assumption of merging on a junction of an expressway from an entrance to a main lane will be explained.The automated merging system based on the automated lane change (PALS) function by the automated driving controller 10 described above generates a target route using information on other vehicles in a merging lane (main lane) obtained by road-to-vehicle communication, performs acceleration / deceleration control (longitudinal control) and steering control (lateral control), performs automated merging (merging assistance) to the merging lane, and is composed of an on-vehicle system and a road-side system.The on-vehicle system includes the automated driving controller 10 constituting the automated lane change system (PALS), a communicator 16 for receiving information on other vehicles through road-to-vehicle communication, and software for performing environment recognition in the environment state estimating part 11 and generating a target route in the route generating part 12 based on the received information on other vehicles.As illustrated in FIG. 5A, the road-side system includes a detection device 61 (such as a camera) for detecting vehicles in a threaded lane 51 (and a neighboring lane 52) of the main lane of the expressway before a merging point, a processing device 6 for analyzing information obtained from the detection device 61 and generating information on other vehicles such as positions and speeds of vehicles traveling in the threaded lane 51 (and the neighboring lane 52), and the inter-vehicle distance and the arrival time at the merging point estimated therefrom, and a road-side communicator 60 for distributing the information on other vehicles to vehicles traveling in a merging lane 50 (entry) through road-to-vehicle communication.For the sake of simplicity, FIG. 5A shows a combination of a first point in time t 1 (bottom) at which a vehicle 1 is travelling on the entry of the merging lane 50 and a second point in time t 2 (top) at which the same vehicle 1 has arrived near a merging point of an acceleration lane; At the first time point t 1, the vehicle 1 that has received the information on other vehicles with the communicator 16 from the roadside communicator 60 performs speed control and route generation up to the merging point based on the information on other vehicles by the automated driving controller 10, performs steering control to follow the route, the flasher flashes in a state in which the vehicle accelerates up to the target speed before reaching the merging point at the second time point t 2, and performs automated merging into an inter-vehicle space S' in the lane 51 being merged.In the case of occurrence of a system failure such as a communicator failure or a communication failure, the road-to-vehicle communication is made redundant, and for example, duplicate measures in the form of radio / optical communication are taken. Further, the steering control and the speed control (vehicle-to-vehicle control) for automated merging may be continued in the case of interruption of the road-to-vehicle communication during the automated merging driving based on detection information of the external sensor 21 of the vehicle 1 itself.(Override Function])The automated merging system has an override function for ending the automated merging and switching to manual driving through an acceleration / deceleration operation intervention or a manual steering intervention of the driver during the automated merging using the road-to-vehicle communication.That is, when an engine torque request via an operation of the accelerator pedal or a deceleration request via an operation of the brake pedal by the driver is equal to or exceeds a corresponding override threshold, override is achieved. These override thresholds are set to an amount of operation of the accelerator pedal (value of the engine torque command) or an amount of operation of the brake pedal (value of the ESP hydraulic command) with which it is determined that the driver has intentionally performed an acceleration deceleration operation, and both are set according to the acceleration / deceleration characteristics and the running state of the vehicle.When a steering torque (or a steering angular velocity) by the driver's manual steering 34 is equal to or greater than the override threshold, override is achieved. The oversteer threshold value by the steering intervention is set according to the steering characteristics and the running state of the vehicle.(Control for Preventing Excessive Operation when Communication Failure Occurs during Automated Threading)When a fault occurs in road-to-vehicle communication during the merging assistance by the automated merging system, the automated merging system attempts to continue automated merging (automated lane change) based on the detection information of the external sensor 21; when it cannot continue automated lane change due to the movement of other vehicles or the like, the driver is alerted to the advance notice of the completion of the automated lane change function and the operation override request, and the fallback control of the automated lane change function is started after the elapse of several seconds; At this time, when the driver who is required of the notification of the completion of the automated lane change and the operation intervention performs a manual driving switch by an excessive steering operation override or an excessive brake pedal / accelerator operation override, the vehicle may approach a following vehicle or approach a vehicle on a neighboring lane due to a lane departure, as described above.The automated driving control apparatus 10 according to the present invention has an excessive operation avoiding function that changes, simultaneously with the occurrence of a failure or simultaneously with the timing of indicating completion of the automated lane change and the operation override request, when a failure occurs in road-to-vehicle communication during the merging assistance by the automated merging system, the override thresholds (accelerator override threshold serving as an accelerator operation intervention determination criterion, brake override threshold serving as a brake pedal operation intervention determination criterion, and steering override threshold serving as a steering operation intervention determination criterion) to a value higher than that during the normal operation.By increasing the override thresholds at the time of occurrence of the failure (or the indication of completion of the automated lane change and the operation override request), override is avoided and the speed control and the automatic steering are continued, whereby excessive acceleration / deceleration and steering are suppressed, and approach to a following vehicle and lane departure can be avoided even if the driver who is overrided from the indication of completion of the automated lane change and the operation override performs an excessive accelerator / brake pedal operation intervention or steering intervention and applies a large amount of operation that would result in acceleration / deceleration or lane departure before the threshold is changed.1. Accelerator / Brake Pedal Override ThresholdFirst, a function for preventing excessive operation by a change in the accelerator / brake override threshold will be described below. A function of avoiding excessive steering by a change in the steering override threshold will be described later.As described above, the automated merging using the road-to-vehicle communication is based on the automated lane change system (PALS), and is implemented by combining the longitudinal control (speed control and inter-vehicle distance control) by the ACC controller 14 and the lateral control (target route following control) by the LKA controller 15. Therefore, the accelerator / brake pedal override threshold is set depending on the override threshold of the ACC function as follows.(Accelerator Pedal Override Threshold in Normal Communication Function)When a value of an engine torque command due to depression of the accelerator pedal by the driver is larger than the value of the engine torque command for maintaining the set ACC speed (set travel speed or preceding vehicle following speed) or the set ACC acceleration, the accelerator pedal override is achieved, and the operation of the accelerator pedal by the driver is given priority. The threshold value is derived from a set of engine torque maps as a function of vehicle speed and transmission ratio, and a value for an engine torque command that gives acceleration by, for example, a speed of 4 km / h with respect to the set ACC speed or an engine torque command that gives acceleration corresponding to 0.3 m / s 2 with respect to the set ACC acceleration is set as the threshold value Td.(Brake Pedal Override Threshold in Normal Communication Function)When an ESP hydraulic command causing a deceleration with respect to the set ACC speed (set running speed or preceding vehicle following speed) or the set ACC acceleration is given by the driver's depression of the brake pedal, the brake override is achieved and the driver's operation of the brake pedal is given priority. The value of the ESP hydraulic command equivalent to a deceleration by a speed of 2 km / h from the set ACC speed, for example, or the value of the ESP hydraulic command equivalent to a deceleration rate of 0.2 m / s 2 from the set ACC acceleration is set as the threshold Pd.(Accelerator Pedal Override Threshold Upon Occurrence of Communication Failure)A value greater than the ACC accelerator override threshold during normal operation is selected, and is preferably in the range of 120% to 250%, and more preferably in the range of 150% to 220%, of the ACC accelerator override threshold during normal operation. For example, a value of an engine torque command that gives an acceleration by a speed of 8 km / h with respect to the set ACC speed or a value of an engine torque command that gives an acceleration corresponding to 0.6 m / s 2 with respect to the set ACC acceleration is set as the threshold To.(Brake Pedal Override Threshold Upon Occurrence of Communication Failure)A value greater than the ACC brake pedal override threshold during normal operation is selected, and is preferably in the range of 120% to 250%, and more preferably in the range of 150% to 220%, of the ACC brake pedal override threshold during normal operation. For example, a value of the ESP hydraulic command equivalent to a deceleration by a speed of 4 km / h from the set ACC speed or a value of the ESP hydraulic command equivalent to a deceleration rate of 0.4 m / s 2 from the set ACC acceleration is set as the threshold Po.2. Steering Override ThresholdThe function of avoiding excessive steering by a change in the steering override threshold is described below. Hereinafter, steering that gives lateral displacement in the same direction as the lane change from the threading lane 50 to the threaded lane 51 (in the expressway shown in FIGS. 5A and 5B, generally, rightward steering) is referred to as additive steering, and steering that gives lateral displacement in the opposite direction to the lane change to the threaded lane 51 (in the expressway shown in FIGS. 5A and 5B, generally, leftward steering) is referred to as subtractive steering.(Steering override threshold in normal communication function)For an additive steering override threshold in normal road-to-vehicle communication, a steering torque (a steering torque calculated from the vehicle speed-steering angle-steering torque map) corresponding to a steering angle by which a virtual lateral displacement y't for reaching a virtual lateral position after t seconds becomes yt+α is set as the additive steering override threshold T 1 d, where α is a constant determined based on the vehicle speed.In subtractive steering, a value which is detectable (determined from the steering angle, the steering angular velocity, or the like) and is applied in a direction in which the steering torque is decreased to a value (target steering torque value) obtained by converting a steering angle by which a virtual lateral displacement yt for reaching a virtual lateral position after t seconds becomes yt+α to a steering torque is set as the subtractive steering override threshold T 2 d, where α is a constant determined based on the vehicle speed.(Steering Override Threshold Upon Occurrence of Communication Failure)For an additive steering override threshold value, a value obtained by converting a steering angle calculated from a virtual lateral displacement y"t (= yt+β, where β>α) upon occurrence of a communication error and the motion characteristics of the vehicle with respect to the virtual lateral displacement yt in a normal communication function into a steering torque is set as the additive steering override threshold value T1o.For a subtractive steering override threshold, a value obtained by converting a steering angle calculated from a virtual lateral displacement y"t (= yt - γ, where γ is larger than a lateral displacement corresponding to a steering torque X' Nm) upon occurrence of a communication error and the motion characteristic of the vehicle with respect to the virtual lateral displacement yt in a normal communication function into a steering torque is set as the subtractive steering override threshold T2o.(Procedure for Preventing Excessive Operation when Communication Failure Occurs during Threading Support)Next, a procedure for avoiding excessive operation by a change in the override threshold upon occurrence of a failure in road-to-vehicle communication during merging assistance by the automated merging system will be described with reference to FIG. 4.(1) The merging assistance by the automated merging system is to receive information on other vehicles through the road-to-vehicle communication with the road-side communicator 60, and perform speed control and route generation to the merging point based on the information on other vehicles when ACCS (speed control and inter-vehicle distance control) and LKAS (steering control) of the vehicle 1 traveling on the merging-leading lane 50 (entry) are active, as illustrated in FIG. 5A (step 100).(2) Communication Error When the automated threading system is active, it is constantly monitored with the abnormality detection function of the communicator 16, and it is determined whether a communication error occurs due to a failure of the communicator itself, a radio wave error, or the like (step 101).(3) If it is determined that a communication failure has occurred, a communication failure flag is set (step 102).(4) At the same time, the accelerator pedal override threshold Td and the brake pedal override threshold Pd are changed to the accelerator pedal override threshold To (To>Td) and the brake pedal override threshold Po (Po>Pd), respectively, in the normal communication function upon occurrence of the communication failure.At the same time, the steering override thresholds (additive direction T 1 dand subtractive direction T 2 d) in the normal communication function are changed to the steering override thresholds (additive direction T 1 oand subtractive direction T 2 o) in the occurrence of the communication error. In the narrow sense, a calculation expression (coefficient) for calculating the steering override thresholds is changed from that in the normal communication function to that in the occurrence of a communication error, and updated depending on the state of movement of the vehicle.(5) Determination of lane change Simultaneously with the occurrence of communication failure, it is determined with the external sensor 21 whether another vehicle is in a predetermined range around the vehicle itself, and it is determined based on the detection information of the external sensor 21 whether automated lane change to the threaded lane 51 is performed (step 103).(6) When there is no other vehicle in the predetermined range around the vehicle itself, automated lane change to the threaded lane 51 is started (step 124). Also after the start of the automated lane change, it is monitored by the external sensor 21 whether other vehicles enter the predetermined area around the vehicle itself and whether the automated lane change is continued based thereon (step 125), and when the merging into the main lane by the automated lane change is completed (step 126), a switch to the PAD travel in the merging lane 51 is performed (step 130).(7) Indication of the Completion of the Automated Lane Change and the Operation TakeoverOn the other hand, when another vehicle is present in the predetermined area around the vehicle itself and it is determined in step 103 that an automated lane change cannot be performed, and it is determined in step 125 that an automated lane change cannot be continued, the driver is notified of the occurrence of a communication error, the completion of the lane change, and the operation override by an output on a head-up display, on an instrument panel, or by voice (step 104). At the same time, counting of a waiting time until switching to the fallback control of the speed control and the vehicle-to-vehicle distance control (ACC function) and the automated steering function is started.(8) Determination of Operation of Accelerator Pedal / Brake Pedal and Manual Steering Are PerformedAt this time, the cruise control and inter-vehicle distance control (ACC function) and the automatic steering function still function, and with position sensors mounted on the accelerator and brake pedals, it is determined whether the driver operates the accelerator pedal or the brake pedal, and at the same time, it is determined with a torque sensor disposed on the EPS controller 31 whether manual steering 34 is performed (step 105).(9-1) Determination of Acceleration Deceleration RequestWhen an operation of the accelerator pedal or brake pedal by the driver is detected in step 105, it is determined whether the driver override is an acceleration request or a deceleration request (step 106).(9-1a) Determination of accelerator pedal overrideIn an acceleration request, the value of an engine torque command due to depression of the accelerator pedal by the driver is compared with the override threshold To (step 108).i) When the value of the engine torque command T>the value of the override threshold To, it is determined that the operation is accelerator pedal override, and the override is immediately performed by switching to manual driving (step 120).ii) When the value of the engine torque command is T≤To, the override is not performed, and the ACC and the automated steering are continued.(9-1b) Determination of brake pedal overrideIn a deceleration request, the value of the ESP hydraulic command due to depression of the brake pedal by the driver is compared with the override threshold Po (step 110).i) When the value of the ESP hydraulic command is P>Po, it is determined that the operation is a brake pedal override, and the override is immediately performed by switching to the manual driving (step 120).ii) When the value of the ESP hydraulic command is P≤Po, the override is not performed, and the ACC and the automated steering are continued.(9-2) Determination of steering directionOn the other hand, when it is determined in step 105 that manual steering is performed by a detection value of the torque sensor disposed on the EPS controller 31, the steering direction of the manual steering 34 is determined (step 107).For determination of the steering direction, it is determined that it is additive steering when the torque is applied in a direction in which the steering torque is increased with respect to the steering torque value that gives a lateral offset for following the route in an automated lane change, and it is determined that it is subtractive steering when the torque is applied in a direction decreasing the steering torque.(9-2a) Determination of Oversteer by Additive SteeringWhen it is determined in the determination of the steering direction that the steering direction is additive steering, the steering torque is compared with the additive steering override threshold T 1 o(step 109).When the steering torque>the value of the additive steering override threshold T 1 o, it is determined that the operation is an override, and the override is immediately performed by switching to the manual driving (step 120).When the steering torque ≤ the value of the additive steering override threshold T 1 o, the override is not performed, and the ACC and the automated steering are continued.(9-2b) Determination of Overdrive by Subtractive SteeringWhen it is determined in the determination of the steering direction that the steering direction is subtractive steering, the steering torque is compared with the subtractive steering override threshold T2o (step 111).If the steering torque>the value of the subtractive steering override threshold T2o, it is determined that the operation is an override, and the override is immediately performed by switching to the manual driving (step 120).If the steering torque ≤ the value of the subtractive steering override threshold T2o, the override is not performed, and ACC and the automated steering are continued.(10) Determination of Elimination of Communication ErrorAfter it is determined in step 102 that a communication fault has occurred, it is constantly monitored by the abnormality detection function of the communicator 16 whether a communication fault has occurred or whether the communication fault has been eliminated (step 112).(11) Clearing a communication failure flagWhen a communication failure is eliminated during continuation of the ACC and the automated steering, the failure flag is cleared, and each override threshold value returns to a value for a normal communication function (step 113).(12) Resumption of Merging Assistance Using Road-to-Vehicle CommunicationWhen a communication failure is eliminated during continuation of the ACC and the automated steering, it is determined whether the merging (lane change) to the lane 51 to be merged is completed (step 114), and when the merging (lane change) is not completed (or not started), the merging assistance using the road-to-vehicle communication is resumed (step 115). On the other hand, when the merging (lane change) is completed, a switch to the PAD travel is performed (step 130).(13) Manual DriveWhen it is determined in step 102 that a communication failure has occurred and the communication failure is not eliminated even after a lapse of a predetermined time after the driver is notified of the occurrence of the communication failure, the completion of the lane change, and the operation intervention (step 116), the speed control and the inter-vehicle distance control (ACC function) and the automated steering function are transferred to the fallback control (step 117), and the automated lane change function is ended, and the steering and the brake / drive operation are adopted by the driver (step 118) by switching to the manual drive (step 120).Although oversteer by excessive steering upon occurrence of a communication error can be substantially avoided by the above-described change in the oversteer threshold value, the ACC and the automated steering functions are oversteered from the manual steering when the manual steering is equal to or greater than the oversteer threshold value in the oversteer determination (step 109 or 111) described above.When the override threshold is changed upon occurrence of communication failure (step 102), by changing the upper limit value of the steering torque or the steering angle set by the EPS controller 31 depending on the vehicle speed (inversely proportional to the vehicle speed / decrease with increasing vehicle speed) to a value smaller than that in a normal communication function, excessive control can be avoided when the manual steering overrides.When the override threshold is changed upon the occurrence of a communication error (step 102), by changing the steering gain of the manual steering by the EPS controller 31 to a small value, it is also possible to take the steering amount in the steering torque into account only partially when oversteering by the manual steering.(Operation and Effects)As explained above, because the travel control apparatus for a vehicle according to the present invention is configured such that the oversteer thresholds serving as a determination criterion for an operation intervention for ending the cruise control and the inter-vehicle distance (ACC) control and the automated steering function are changed to a value higher than a normal communication function when a communication failure occurs during the merging assistance using the road-to-vehicle communication, effects of avoiding an excessive operation can be expected in cases explained below.For example, as illustrated in FIG. 5A, the vehicle 1 receives information on other vehicles (vehicles 2 and 4, inter-vehicle gaps S 2, and the like) in the threaded lane 51 from the road side communicator 60 at the first time t 1, and performs speed control and route generation to a merging point based on the information on other vehicles; However, as illustrated in FIG. 5B, when a communication failure occurs at a first time point t1' and the information on other vehicles in the threaded lane 51 cannot be detected, the vehicle attempts to continue automated threading (automated lane change) with sensor information of the vehicle 1 at a second time point t2' but when it is determined that the automated threading with sensor information cannot be continued due to the movement of other vehicles or the like, the driver is alerted to the advance notice of the completion of the automated lane change function and the operation override request, and the fallback control of the automated lane change function is started after the elapse of several seconds.At this time, even if the driver who is required of the indication of the occurrence of a communication failure, the completion of the automated merging, and the operation override request performs an excessive steering operation or a brake / drive operation, because the steering override thresholds and the accelerator pedal / brake pedal override thresholds serving as the determination criterion for an operation intervention are changed to a value higher than a normal communication function, override can be avoided, enabling the switching to the fallback control in the state in which the speed control and the inter-vehicle distance (ACC) control and the automated steering function are continued, as illustrated in FIG. 5B, and lane departure (OR) to the right due to excessive steering intervention and approach to a preceding vehicle 2 (OA) or approach to a following vehicle 3 (OA) due to excessive operation intervention can be avoided.The embodiment illustrates the case where both the ACC function (longitudinal control) and the automatic steering function (lateral control) switch to fallback control upon occurrence of a communication error, but it is possible to effect switching of only the automatic steering function (lateral control) to fallback control.Although only the case where the accelerator pedal override threshold is set based on the engine torque request due to an operation of the accelerator pedal by the driver has been described in the embodiment, the accelerator pedal override threshold may be configured to be set based on the operation of the accelerator pedal by the driver, i.e., an accelerator pedal position.In the same manner, although only the case where the brake pedal override threshold is set based on the deceleration request due to an operation of the brake pedal by the driver has been described in the embodiment, the brake pedal override threshold may also be configured to be set based on the depression of the brake pedal by the driver, i.e., a brake pedal position.Although in the embodiment, the case where the steering override threshold value is set based on the steering torque has been exemplified, the steering override threshold value may also be configured to be set based on the steering angle, the steering angular velocity, or the like.Although some embodiments of the present invention are described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the present invention.[List of Reference Numerals]1 Vehicle (the vehicle) 2, 4 Vehicle (other vehicle in the threaded lane) 3 Vehicle (other vehicle in the threaded lane) 6 Processing device 10 Automated driving controller 11 Environmental state estimating part 12 Route generating part 13 Vehicle control part 14 ACC controller 15 LKA controller 16 Communicator 21 External sensor 22 Internal sensor 31 EPS controller 32 Motor controller 33 ESP / ABS controller 34 Manual steering (steering wheel) 41 Steering 42 Motor 43 Brake 50 Threaded lane 51 Threaded lane 60 Road-side communicator 61 Detection device

Claims

A driving control apparatus (10) for a vehicle (1) comprising: an environment state estimating part (11) comprising an environment recognition function (21) for recognizing a driving lane of the vehicle (1) and adjacent lanes and other vehicles in the respective driving lanes, a function (22) for obtaining the moving state of the vehicle (1) and a communication function (16) for obtaining information on other vehicles in a threaded driving lane; a route generating part (12) for generating a target route based on information obtained from the environment state estimating part (11); A vehicle control part (13) for performing acceleration / deceleration control and steering control for causing the vehicle (1) to follow the target route, comprising: a function for generating a target route to a predetermined area as a target and performing automated lane change to a neighboring lane when no other vehicle is detected by the surrounding detection function (11, 21) in the predetermined area of the neighboring lane; and a merging assistance function for generating a target route using the information on other vehicles obtained by the communication function (16), performing acceleration / deceleration control and steering control and automatically merging into the lane being merged; characterized in that the travel control device (10) has a function that changes oversteer thresholds (Pd, Td, T1d, T2d) serving as a determination criterion for an operation intervention for ending the acceleration / deceleration control and the steering control to a value (Po, To, T1o, T2o) that is higher than during the normal operation of the communication function (16) when an error occurs in the communication function (16) during the automatic merging.The travel control device (10) for a vehicle (1) according to claim 1, wherein, when a failure occurs in the communication function (16) during the automatic merging, when merging by an automated lane change based on the environment recognition function (11, 21) is possible, merging by the automated lane change is continued, and when merging by an automated lane change based on the environment recognition function (11, 21) is impossible or continuation is not possible, the driver is alerted to the completion of the automated lane change function and to the operation override, switching to a fallback control of the automated lane change function.The travel control device (10) for a vehicle (1) according to claim 1 or 2, wherein, when the failure of the communication function (16) is eliminated within a predetermined period of time after the occurrence of the failure in the communication function (16) during the automated threading, the override thresholds serving as a determination criterion for an operation intervention for ending the acceleration / deceleration control and the steering control return to a value (Pd, Td, T1d, T2d) during the normal operation of the communication function (16).The travel control device (10) for a vehicle (1) according to claim 3, wherein, when the failure of the communication function (16) is eliminated within the predetermined period after the occurrence of the failure in the communication function (16) during the automated merging, if the merging into the lane to be merged is not completed, the automated merging is resumed using the information on other vehicles obtained from the communication function (16).The travel control device (10) for a vehicle (1) according to claim 2, wherein when the failure of the communication function (16) is not eliminated within the predetermined period after occurrence of the failure in the communication function (16) during the automated merging, the switching to the fallback control of the automated lane change function is performed.The travel control device (10) for a vehicle (1) according to any one of claims 1 to 5, wherein the override thresholds include an accelerator pedal override threshold (Pd, Po) serving as a determination criterion for the accelerator pedal operation intervention and / or a brake pedal override threshold (Td, To) serving as a determination criterion for the brake pedal operation intervention.The travel control device (10) for a vehicle (1) according to any one of claims 1 to 6, wherein the override thresholds include steering override thresholds (T1d, T2d, T1o, T2o) serving as a determination criterion for the steering operation intervention, the steering override thresholds including an additive steering override threshold (T1d, T1o) in the same direction as the lane change to the to-be-threaded lane and a subtractive steering override threshold (T2d, T2o) in an opposite direction to the lane change to the to-be-threaded lane, different values being set for the additive steering override threshold (T1d, T1o) and the subtractive steering override threshold (T2d, T2o).

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