Vehicle driving control system

Abstract

The present invention provides a driving control system for a vehicle that evaluates the level of deterioration of the driving environment and continues the driving assistance mode that does not require the driver to steer the steering wheel as much as possible. The automatically driven vehicle speed calculation unit calculates the automatically driven vehicle speed Vd1 that can continue the second driving assistance mode based on the evaluation result of the deterioration level of the driving environment. The driving assistance mode continuation judgment unit compares the set vehicle speed Vat of the second driving assistance mode with the automatically driven vehicle speed Vd1. When Vat≤Vd1, it is judged that the second driving assistance mode can be continued. When Vat>Vd1, it is judged that the second driving assistance mode cannot be continued, and the driver is allowed to select the second or first driving assistance mode through the driving assistance mode selection unit. When the second driving assistance mode is selected, the driving assistance mode continuation unit reduces the set vehicle speed Vat to the automatically driven vehicle speed Vd1, thereby enabling driving in the second driving assistance mode.

Description

Technical Field

[0001] The present invention relates to a vehicle driving control system including a driving assistance mode that presupposes that a driver steers a steering wheel and a driving assistance mode that does not require the driver to steer the steering wheel. Background Art

[0002] In order to reduce the burden on drivers and achieve comfortable and safe driving in vehicles such as cars, systems that can automatically drive the vehicle without the driver steering the wheel have been developed, and some of them have been put into practical use. In order to realize the automatic driving function, reliable perception of the surrounding environment and stability of the road environment are required. When the surrounding environment and / or road environment deteriorate, it is necessary to limit the automatic driving function or switch from automatic driving to a driving assistance mode that requires the driver to steer the wheel.

[0003] For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2017-128180) discloses a technology in which only functions that are judged to be difficult to continue autonomous driving are taken over by the driver's operation, and only other autonomous driving functions are continued.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-128180 Summary of the invention

[0007] Technical issues

[0008] In the existing technology, whether or not the automatic driving can be continued is determined solely based on the deterioration of the driving environment. However, there are cases where the automatic driving can be continued according to the conditions even if the driving environment deteriorates. In this case, if the automatic driving function is solely limited or the mode is switched to a driving assistance mode that requires the driver to steer the steering wheel, the driver must adjust the driving posture in a short time, which not only increases the burden on the driver but also impairs the convenience of the automatic driving.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle driving control system that evaluates the level of deterioration of the driving environment and can continue a driving assistance mode that does not require the driver to steer the steering wheel as much as possible.

[0010] Technical Solution

[0011] A driving control system for a vehicle according to one embodiment of the present invention comprises: a manual driving mode; a first driving assistance mode in which driving assistance control is performed on the premise that the driver steers the steering wheel; and a second driving assistance mode in which driving assistance control is performed without the driver steering the steering wheel, the driving control system for the vehicle comprising: an automatically driving vehicle speed calculation unit for evaluating the degree of deterioration of the driving environment during driving in the second driving assistance mode and calculating the automatically driving vehicle speed at which the second driving assistance mode can be continued based on the degree of deterioration of the driving environment; a driving assistance mode continuation determination unit for comparing the vehicle speed in the second driving assistance mode with the automatically driving vehicle speed to determine whether the driving assistance control based on the second driving assistance mode can be continued; and a driving assistance mode continuation unit for reducing the vehicle speed in the second driving assistance mode to the automatically driving vehicle speed when the driving assistance mode continuation determination unit determines that the driving assistance control based on the second driving assistance mode cannot be continued, thereby enabling the driving assistance control based on the second driving assistance mode to be continued.

[0012] A vehicle driving control system according to another embodiment of the present invention comprises: a manual driving mode; a first driving assistance mode that performs driving assistance control on the premise that the driver steers the steering wheel; and a second driving assistance mode that performs driving assistance control without the driver steering the steering wheel, and the driving control system of the above-mentioned vehicle comprises: an automatically driving vehicle speed calculation unit that evaluates the degree of deterioration of the driving environment during driving in the above-mentioned second driving assistance mode, and calculates the automatically driving vehicle speed that can continue the above-mentioned second driving assistance mode based on the degree of deterioration of the above-mentioned driving environment; a driving assistance mode continuation judgment unit that compares the vehicle speed in the above-mentioned second driving assistance mode with the above-mentioned automatically driving vehicle speed a driving assistance mode selection unit, which enables the selection of either continuing the second driving assistance mode or transferring to the first driving assistance mode when the driving assistance mode continuation judgment unit determines that the driving assistance control based on the second driving assistance mode cannot be continued; and a driving assistance mode continuation unit, which enables the selection of continuing the second driving assistance mode and transferring to the first driving assistance mode when the driving assistance mode continuation judgment unit selects to continue the second driving assistance mode, by reducing the vehicle speed of the driving assistance mode to the vehicle speed that can be automatically driven, thereby enabling the driving assistance control based on the second driving assistance mode to be continued.

[0013] Effects of the Invention

[0014] According to the present invention, the level of deterioration of the driving environment can be evaluated and the driving assistance mode which is not premised on the driver steering the steering wheel can be continued as much as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a diagram showing the configuration of a vehicle's travel control system.

[0016] Figure 2 It is an explanatory diagram showing the transition of the driving assistance mode.

[0017] Figure 3 : is a flowchart showing the main routine of the driving assistance mode transition process.

[0018] Figure 4 This is a flowchart showing a subroutine for calculating the stable vehicle speed during automatic driving in crosswinds.

[0019] Figure 5 This is a flowchart showing a subroutine for calculating the stable vehicle speed during automatic driving in rainy weather.

[0020] Figure 6 This is a flowchart showing a subroutine for calculating the stable vehicle speed during automatic driving during snowfall.

[0021] Figure 7 This is a flowchart showing a subroutine for calculating a stable vehicle speed for automatic driving on a road surface.

[0022] Explanation of symbols

[0023] 1: Driving control system

[0024] 10: External environment recognition device

[0025] 20: Positioning device

[0026] 30: Map information processing device

[0027] 40: Engine control unit

[0028] 50: Transmission control device

[0029] 60: Brake control device

[0030] 70: Steering control device

[0031] 80: Alarm control device

[0032] 100: Driving control device

[0033] 101: Automatic driving speed calculation unit

[0034] 102: Driving assistance mode continuation judgment unit

[0035] 103: Driving assistance mode selection unit

[0036] 104: Driving assistance mode continued DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 In the figure, reference numeral 1 is a driving control system for a vehicle such as an automobile, which performs driving control including autonomous automatic driving of the vehicle. The driving control system 1 is structured with a driving control device 100 as the center, and includes an external environment recognition device 10, a positioning device 20, a map information processing device 30, an engine control device 40, a transmission control device 50, a brake control device 60, a steering control device 70, and an alarm control device 80, and each device is connected to a network via a communication bus 150.

[0038] The external environment recognition device 10 includes: various devices for environment recognition such as a vehicle-mounted camera unit 11, a radar device 12 such as a millimeter wave radar and / or a laser radar, and / or various sensors such as an outside temperature sensor 13 that detects the outside temperature as one of the meteorological conditions of the outside environment in which the vehicle is traveling. In addition to using detection information of objects around the vehicle detected by the camera unit 11 and / or the radar device 12, and environmental information such as the outside temperature detected by the outside temperature sensor 13 to recognize the external environment around the vehicle, the external environment recognition device 10 also uses traffic information acquired through infrastructure communications such as road-to-vehicle communication and / or vehicle-to-vehicle communication, the position information of the vehicle located by the positioning device 20, and map information from the map information processing device 30 to recognize the external environment around the vehicle.

[0039] For example, when a stereo camera composed of two cameras that photograph the same object from different viewing angles is mounted as the camera unit 11, the external environment can be recognized in three dimensions by stereo processing a pair of left and right images photographed by the stereo camera. The camera unit 11 as a stereo camera is, for example, configured by arranging two color cameras having shutter synchronization of a photographing element such as a CCD and / or a CMOS on the left and right sides of the vehicle width direction with a predetermined base line length near the rearview mirror inside the front window in the upper part of the vehicle interior.

[0040] The pixel offset (parallax) of the corresponding positions between the left and right images captured by the camera unit 11 as a stereo camera is obtained by matching processing, and a distance image is generated by converting the pixel offset into brightness data, etc. Based on the principle of triangulation, the coordinates of points on the distance image are converted into points in the real space with the vehicle width direction, i.e., the left and right direction, as the X-axis, the vehicle height direction, as the Y-axis, and the vehicle length direction, i.e., the distance direction, as the Z-axis, to three-dimensionally recognize the white lines (lane lines) of the road on which the vehicle is traveling, obstacles, and vehicles traveling in front of the vehicle, etc.

[0041] By extracting a group of points that are candidates for white lines from an image and calculating straight lines and / or curves connecting the candidate points, it is possible to identify white lines on a road as lane lines. For example, in a white line detection area set on an image, edges whose brightness changes by a predetermined amount or more are detected on a plurality of search lines set along the horizontal direction (vehicle width direction), a group of white line start points and white line end points are detected for each search line, and an intermediate area between the white line start point and the white line end point is extracted as a white line candidate point.

[0042] Then, the time series data of the spatial coordinate position of the white line candidate point based on the vehicle movement amount per unit time is processed to calculate a model approximating the left and right white lines, and the white line is recognized using the model. As the approximate model of the white line, an approximate model obtained by connecting straight line components obtained by Hough transform or a model approximated by a curve such as a quadratic equation can be used.

[0043] The positioning device 20 detects the vehicle position of the host vehicle mainly by positioning based on signals from multiple navigation satellites such as GNSS (Global Navigation Satellite System) satellites. In addition, when the positioning accuracy is deteriorated due to the capture state of the signal (radio wave) from the satellite and / or the multi-channel influence caused by the reflection of the radio wave, the vehicle position of the host vehicle is detected by positioning using autonomous navigation using vehicle-mounted sensors such as a gyro sensor 22 and / or a vehicle speed sensor 23.

[0044] In the positioning performed by multiple navigation satellites, a signal including information related to the orbit and time, etc. transmitted from the navigation satellite is received via the receiver 21, and the own position of the vehicle is located as an absolute position including longitude, latitude, altitude and time information based on the received signal. In addition, in the positioning performed by autonomous navigation, the position of the vehicle as a relative position change is located based on the travel direction of the vehicle detected by the gyro sensor 22 and the moving distance of the vehicle calculated from the vehicle speed pulse output from the vehicle speed sensor 23.

[0045] It should be noted that the positioning device 20 may be integrally provided with a communication unit for acquiring traffic information through infrastructure communication such as road-to-vehicle communication and / or vehicle-to-vehicle communication.

[0046] The map information processing device 30 includes a map database DB, and determines and outputs a position on the map data of the map database DB based on the position data of the vehicle located by the positioning device 20. The map database DB is a database storing high-precision maps produced for vehicle control including driving assistance control for automatic driving, and is stored in a large-capacity storage medium such as a HDD (hard disk drive) and / or an SSD (solid state drive).

[0047] In detail, the high-precision map is constructed as a multi-dimensional map (dynamic map) that stores static information such as road shapes and / or connections between roads, and dynamic information such as traffic information collected through infrastructure communication in multiple levels. Road data includes the type of white line on the road, the number of lanes, the width of the lanes, point column data indicating the center position of the lane in the width direction, the curvature of the lane, the direction of travel of the lane, the speed limit, etc. It is stored together with attribute data such as the reliability of the data and / or the date of data update.

[0048] In addition, the map information processing device 30 performs maintenance management of the map database DB, checks the nodes, links, and data points of the map database DB and always maintains them in the latest state, and also creates and adds new data to areas where data does not exist in the database to build a more detailed database. The data update and new data addition of the map database DB are performed by comparing the position data obtained by positioning using the positioning device 20 with the data stored in the map database DB.

[0049] It should be noted that the information from the map information processing device 30 is mainly transmitted to the travel control device 100, but is also transmitted to other control devices as necessary.

[0050] The engine control device 40 controls the operating state of the engine (not shown) based on signals from various sensors that detect the operating state of the engine and various control information sent via the communication bus 150. The engine control device 40 performs engine control mainly including fuel injection control, ignition timing control, and electronic throttle opening control based on, for example, the amount of intake air, throttle opening, engine water temperature, intake air temperature, air-fuel ratio, crank angle, accelerator opening, and other vehicle information.

[0051] The transmission control device 50 controls the oil pressure supplied to the automatic transmission (not shown) based on signals from sensors that detect the shift position and / or vehicle speed and / or various control information sent via the communication bus 150, and controls the automatic transmission according to a preset shift characteristic.

[0052] The brake control device 60 controls the brake devices (not shown) of the four wheels independently of the driver's brake operation based on, for example, the brake switch, the wheel speeds of the four wheels, the steering angle, the yaw rate, and other vehicle information. In addition, the brake control device 60 calculates the brake fluid pressure of each wheel based on the braking force of each wheel, and performs anti-lock brake system control and / or anti-skid control, etc.

[0053] The steering control device 70 controls the steering torque generated by the electric power steering motor (not shown) provided in the steering system based on, for example, the vehicle speed, the steering torque of the driver, the steering angle, the yaw rate, and other vehicle information. The control of the steering torque is performed as a current control of the electric power steering motor to achieve a target steering torque for making the actual steering angle consistent with the target steering angle. In the absence of an override caused by the steering operation of the driver, the drive current of the electric power steering motor is controlled by, for example, PID control.

[0054] The alarm control device 80 is a device that controls the output of alarms and various information to be presented to the driver when abnormalities occur in various devices of the vehicle and / or to draw the driver's attention. For example, the alarm / information presentation is performed using at least one of visual outputs such as monitors, displays, and warning lights, and auditory outputs such as speakers / buzzers. The alarm control device 80 presents the driver with the control status during the execution of driving assistance control including automatic driving, and in addition, when the driving assistance control including automatic driving is stopped according to the driver's operation, the driver is notified of the driving status at that time.

[0055] Next, the driving control device 100 that is the core of the driving control system 1 will be described. In the manual driving mode in which the driver holds the steering wheel and steers, when the driver operates a switch and / or panel (not shown) and sets the driving mode to driving assistance, the driving control device 100 performs control of the driving assistance mode including automatic driving via the engine control device 40, the transmission control device 50, the brake control device 60, and the steering control device 70. In this embodiment, as the driving modes set for the driving control device 100, a manual driving mode, a first driving assistance mode, a second driving assistance mode, and an automatic parking mode that automatically stops the vehicle at a safe place such as a curb are set.

[0056] Here, the manual driving mode is a driving mode in which the vehicle is driven according to driving operations such as steering, acceleration and braking performed by the driver. With respect to the manual driving mode, when the external environment recognition device 10 or the like recognizes that there is a preceding vehicle ahead on the road on which the vehicle is traveling, the first driving assistance mode and the second driving assistance mode can set a target path based on the driving trajectory of the preceding vehicle, and automatically follow the preceding vehicle without causing the vehicle to leave the lane (automatic driving). In addition, in the first driving assistance mode and the second driving assistance mode, when the preceding vehicle is not recognized, for example, the path of the vehicle to the destination can be set, and the set vehicle speed can be used as the target vehicle speed to cause the vehicle to automatically drive along the path of the vehicle.

[0057] The first driving assistance mode and the second driving assistance mode are basically the same in that they are driving modes for automatic driving that enable the vehicle to drive automatically based on sensing information and recognition information of the driving environment, but the first driving assistance mode is a driving mode in which driving assistance control is performed on the premise that the driver steers (holds) the steering wheel, and the second driving assistance mode is a driving mode in which driving assistance control is performed without the driver steering the steering wheel. When driving assistance based on the second driving assistance mode cannot be continued, the mode is transferred to the first driving assistance mode, the manual driving mode, or the automatic parking mode according to the conditions.

[0058] It should be noted that whether the driver is steering (holding the steering wheel) is detected based on a signal from a steering wheel touch sensor (not shown) that is turned on when the driver is steering (holding the steering wheel).

[0059] The driving control device 100 monitors the change of the driving environment during driving in the second driving assistance mode without the driver steering the steering wheel, and determines whether the second driving assistance mode can be continued due to the deterioration of the driving environment. In detail, the driving control device 100 quantitatively evaluates the level of deterioration of the driving environment during driving in the second driving assistance mode, and calculates the vehicle speed (automatic driving speed) Vd1 at which the second driving assistance mode can be continued based on the evaluation result. The automatic driving speed Vd1 is calculated as a vehicle speed that can maintain automatic driving by reducing the vehicle speed in response to the deterioration of the driving environment, thereby ensuring a safety margin in automatic driving.

[0060] The driving control device 100 checks whether the set vehicle speed Vat of the second driving assistance mode exceeds the vehicle speed Vd1 that can be automatically driven. When the set vehicle speed Vat is less than the vehicle speed Vd1 that can be automatically driven (Vat≤Vd1), the driving control device 100 continues the second driving assistance mode. On the other hand, when the set vehicle speed Vat exceeds the vehicle speed Vd1 that can be automatically driven (Vat>Vd1), the driving control device 100 can continue the second driving assistance mode by reducing the set vehicle speed Vat to the vehicle speed Vd1 that can be automatically driven.

[0061] That is, during driving in the second driving assistance mode, when the vehicle speed Vd1 at which the vehicle can be automatically driven is lower than the driving speed, the driving speed is reduced to the vehicle speed Vd1 at which the vehicle can be automatically driven to become a new set vehicle speed Vat (Vat←Vd1), thereby ensuring a safety margin when maintaining the level of automatic driving, and enabling safe driving by utilizing the automatic driving in the second driving assistance mode.

[0062] At this time, the travel control device 100 may automatically reduce the vehicle speed to the vehicle speed Vd1 for automatic driving and continue the second driving assistance mode, or may allow the driver to select whether to continue the second driving assistance mode.

[0063] When the vehicle speed Vd1 that can be automatically driven is lower than the set vehicle speed Vat in the second driving assistance mode due to the deterioration of the driving environment (Vd1<Vat), the driving control device 100 continues the second driving assistance mode according to the driver's selection, or switches from the second driving assistance mode to the first driving assistance mode. When switching from the second driving assistance mode to the first driving assistance mode, the driver can maintain the set vehicle speed Vat by judging the change in the driving environment.

[0064] Therefore, the driving control device 100 includes an automatically driving vehicle speed calculation unit 101, a driving assistance mode continuation determination unit 102, a driving assistance mode selection unit 103, and a driving assistance mode continuation unit 104 as functional units related to the driving assistance mode. Through these functional units, the driving control device 100 can continue the automatic driving in the second driving assistance mode even when the driving environment deteriorates while the vehicle is driving in the second driving assistance mode without the driver steering the steering wheel.

[0065] Specifically, the automatically drivable vehicle speed calculation unit 101 monitors the changes in weather conditions, road conditions, and vehicle control conditions as driving environments, and calculates the automatically drivable vehicle speed Vd1 by evaluating the parameters that change with each other according to the conditions. As weather conditions, the influence of crosswind, rain, and snowfall is evaluated, and as road conditions, the influence caused by the magnitude of the road friction coefficient is evaluated. In addition, as vehicle control conditions, the lateral position controllability of the vehicle relative to the target path, the visibility distance for controlling the front and rear positions of the vehicle, the steering controllability, etc. are evaluated.

[0066] The automatic driving speed calculation unit 101 classifies the scenes according to the weather conditions, road conditions, and vehicle control conditions, and calculates the speed at which the automatic driving can be performed stably for each scene. In this embodiment, as described later, the automatic driving stable speeds Vd1_w, Vd1_r, Vd1_s, and Vd1_μ are calculated for each scene of crosswind, rain (including fog and snow), snowfall, and road conditions. Then, the lowest speed among the calculated automatic driving stable speeds Vd1_w, Vd1_r, Vd1_s, and Vd1_μ for each scene is used as the final automatic driving speed Vd1.

[0067] The driving assistance mode continuation determination unit 102 compares the set vehicle speed Vat in the second driving assistance mode with the vehicle speed Vd1 at which the automatic driving can be performed, and determines that the second driving assistance mode can be continued when Vat≤Vd1, and determines that the second driving assistance mode cannot be continued when Vat>Vd1. When it is determined that the second driving assistance mode cannot be continued, the driving assistance mode continuation determination unit 102 allows the driver to select whether to reduce the vehicle speed and continue the second driving assistance mode in which the driver does not need to steer the wheel, or to shift to the first driving assistance mode in which the driver needs to steer the wheel, via the driving assistance mode selection unit 103.

[0068] In addition, the driving assistance mode continuation determination unit 102 checks whether the vehicle speed Vd1 that can be automatically driven is lower than the minimum vehicle speed determined by the dedicated lane for automobiles or the predetermined lower limit vehicle speed Vd2. In the case of Vd1<Vd2, even if the vehicle is transferred to the first driving assistance mode, the driving assistance mode continuation determination unit 102 determines that it is difficult to continue the driving assistance control. In this case, the driver is required to drive manually, or the vehicle is transferred to the automatic parking mode so that the vehicle automatically moves to a safe place and stops.

[0069] When the driving assistance mode continuation judgment unit 102 determines that the second driving assistance mode cannot be continued, the driving assistance mode selection unit 103 notifies the driver of the automatic driving level that the second driving assistance mode cannot be continued in the current state, so that the driver can choose to continue the second driving assistance mode or transfer to the first driving assistance mode.

[0070] The selection of the driving assistance mode is a selection request for the driver to select whether to reduce the set vehicle speed Vat to the vehicle speed Vd1 at which the automatic driving can be performed and continue the automatic driving in the second driving assistance mode, or to reduce the automatic driving level from the second driving assistance mode that does not require the driver to steer the steering wheel to the first driving assistance mode that requires the driver to steer the steering wheel. When the selection request is received and it is detected that the driver is steering the steering wheel, it is determined that the first driving assistance mode is selected, and the second driving assistance mode is automatically switched to the first driving assistance mode.

[0071] The driving assistance mode continuing unit 104 continues the second driving assistance mode or shifts from the second driving assistance mode to the first driving assistance mode according to the selection result obtained by the driving assistance mode selecting unit 103. If the second driving assistance mode is selected to be continued, the driving assistance mode continuing unit 104 reduces the set vehicle speed Vat of the second driving assistance mode to the vehicle speed Vd1 at which the automatic driving is possible, thereby enabling driving by the automatic driving in the second driving assistance mode.

[0072] use Figure 2 The continuation or transfer of the above second driving assistance mode is described. Figure 2 In the figure, the vertical axis represents the vehicle speed, and the horizontal axis represents the driving environment level, which represents the change of the driving environment. The driving environment level here is an indicator of the driving environment that can continue the second driving assistance mode by a value equivalent to the vehicle speed in relation to the vehicle speed Vd1 that can be driven automatically. Figure 2 The level of the driving environment changes from a good state to a deteriorated state from the left side to the right side.

[0073] like Figure 2 As shown in area A of the figure, while the vehicle is traveling in the second driving assistance mode, if the environmental level deteriorates compared to the state of environmental level KV1 where Vat>Vd1, then, for example, as shown in area B of the figure, the vehicle speed Vd1 that can be automatically driven decreases approximately linearly relative to the set vehicle speed Vat corresponding to the deterioration of the environmental level. If the vehicle speed is not reduced, it will be difficult to continue the second driving assistance mode.

[0074] In this state, when the driver is steering the steering wheel, the mode is switched to the first driving assistance mode. When the driver is not steering the steering wheel, the vehicle speed is reduced to Vat≤Vd1, so that the second driving assistance mode can be continued. When the second driving assistance mode is continued, if the driving environment further deteriorates and becomes a zone C where the environment level KV2 is worse than the vehicle speed Vd1 that can be automatically driven and is lower than the predetermined lower limit vehicle speed Vd2, the second driving assistance mode is switched to the automatic parking mode, and the vehicle is automatically stopped at the roadside to ensure safety.

[0075] Next, use Figure 3 to Figure 7 The flowchart of FIG. 1 illustrates the transition process of the driving assistance mode in the travel control device 100 . Figure 3 is a flowchart showing the main routine of the driving assistance mode transition process, Figure 4 to Figure 7 This is a flowchart showing a subroutine for calculating and processing the vehicle speed that can be automatically driven in various scenarios such as crosswind, rain, snow, and road conditions.

[0076] First of all, Figure 3 In the main routine, first, in steps S1A, S1B, S1C, and S1D, the driving control device 100 processes the driving assistance mode transfer process in parallel. Figure 4 , Figure 5 , Figure 6 , Figure 7 Subroutines. Each subroutine assumes a crosswind scenario, a rain (including fog and snow) scenario, a snowfall scenario, and a low-friction road scenario, and calculates a crosswind stable vehicle speed Vd1_w for the crosswind scenario, a rain (including fog and snow) stable vehicle speed Vd1_r for the rain scenario, a snowfall stable vehicle speed Vd1_s for the snowfall scenario, and a road surface stable vehicle speed Vd1_μ for the low-friction road scenario.

[0077] [Autonomous driving stable speed Vd1_w in crosswind]

[0078] The crosswind automatic driving stable vehicle speed Vd1_w in step S1A is calculated as a vehicle speed that can ensure the steering performance to maintain the lateral position of the host vehicle within the allowable range relative to the target path. Figure 4 In the first step S101, it is checked whether the variance of the lateral position for a certain period of time is greater than a set value (for example, greater than ±10 cm).

[0079] In step S101, if the variance of the lateral position is less than the set value and is stable, the process proceeds to step S102, and further, it is checked whether the integral value of the lateral deviation is a constant value continuously, thereby judging the influence of external disturbances caused by the road slope, etc. As a result, in steps S101 and S102, if the variance of the lateral position is less than the set value and the integral value of the lateral deviation is not a constant value continuously, it is judged that the second driving assistance mode for external disturbances can be automatically driven. At this time, the automatic driving stable vehicle speed Vd1_w in crosswind is set to Vd1_w=Vd1, for example, and the process returns to the main routine.

[0080] On the other hand, if the variance of the lateral position is greater than the set value in step S101, or if the integral value of the lateral deviation continues to be a certain value in step S102, it is checked in step S103 whether the curve of the road being traveled is a sharp curve with a curvature smaller than the curvature of the normal curve that is the object of automatic travel. If it is a sharp curve in step S103, the present process is exited because the influence of external disturbances such as crosswind and / or road slope cannot be correctly evaluated. If it is not a sharp curve, the process proceeds to step S104.

[0081] In step S104, the vehicle speed that can ensure the steering performance in lane following control for crosswind, road slope, and curve curvature is calculated, for example, by mapping reference based on the variance value and integral value of the lateral position. The vehicle speed at this time is saved as the automatic driving stable vehicle speed Vd1_w in crosswind and is referenced in the main routine.

[0082] [Autonomous driving stable speed Vd1_r in rainy weather]

[0083] The rainy day automatic driving stable vehicle speed Vd1_r in step S1B is calculated as the vehicle speed that can ensure the required visibility distance for steering and front and rear position control to follow the target path. Figure 5 In the subroutine of , first, in step S201, it is checked whether the lane detection range obtained from the map information from the vehicle-mounted camera unit 11 or the map information processing device 30 is smaller than the lane detection distance that can be used for steering control, and in step S202, it is checked whether the white line detection distance of the camera unit 11 is smaller than the detection distance that can be used for steering control when the map information cannot be used. In addition, in step S203, it is checked whether the current visibility distance is smaller than the visibility distance that can control the front and rear position relative to the vehicle in front by braking control or the like.

[0084] As a result, when the detection range of the white line or the detection range of the lane obtained from the map data is greater than the detection distance at which steering control can be performed and the visibility distance at which front and rear position control can be performed can be ensured, it is determined that automatic driving in the second driving assistance mode can be performed and the program returns to the main routine. At this time, the automatic driving stable vehicle speed Vd1_r in rainy weather is set to Vd1_r=Vd1, for example, and saved, and referenced in the main routine.

[0085] On the other hand, in steps S201, S202, and S203, if the detection range of the white line or the detection range of the lane obtained from the map data is smaller than the detection distance at which the steering control can be performed, or smaller than the visual distance at which the front and rear position control can be performed, the process proceeds to step S204, and the vehicle speed at which the detection distance and / or the visual distance for the lane (white line) can ensure the steering performance of the automatic driving is calculated by mapping reference, etc. The vehicle speed at this time is set as the automatic driving stable vehicle speed Vd1_r in rainy days and stored, and is referred to in the main routine.

[0086] [Autonomous driving stable speed Vd1_s during snowfall]

[0087] The snowfall automatic driving stable vehicle speed Vd1_s in step S1C is calculated as a vehicle speed that can ensure the visibility distance required for steering control without using the on-vehicle camera unit 11. Figure 6 In steps S301 and S302 of the subroutine, it is checked whether the reliability of the positioning achieved by the positioning device 20 and the map information processing device 30 is less than the position reliability of the steering control that can be used for automatic driving, and whether it is less than the visibility distance that can be used for front and rear position control.

[0088] If the reliability of positioning in step S301 is greater than the reliability of position for steering control that enables automatic driving, and if the distance is greater than the visibility distance that enables front and rear position control in step S302, it is determined that automatic driving in the second driving assistance mode is possible, and the process returns to the main routine. At this time, the automatic driving stable vehicle speed Vd1_s during snowfall is set to Vd1_s=Vd1, for example.

[0089] On the other hand, if the positioning reliability in step S301 is less than the position reliability for steering control that enables automatic driving, or if the positioning reliability in step S302 is less than the visibility distance that enables front and rear position control, the process proceeds to step S303. In step S303, the automatic driving stable vehicle speed Vd1_s during snowfall is calculated based on the positioning reliability or the visibility distance, and the process returns to the main routine.

[0090] [Road automatic driving stable vehicle speed Vd1_μ]

[0091] The road automatic driving stable vehicle speed Vd1_μ in step S1D is calculated as a vehicle speed at which the steering angle-yaw rate gain for obtaining the target yaw rate can be maintained and the steering performance can be ensured even on a slippery road surface.

[0092] In detail, Figure 7In the first step S401 of the subroutine, it is checked whether the yaw rate gain with respect to the steering angle is below a certain value. In other words, it is checked whether the driving state on the current road surface is such that the change of the yaw rate with respect to the steering angle is small and an appropriate yaw angle cannot be obtained for the traveling direction.

[0093] When the yaw rate gain with respect to the steering angle is below a certain value in step S401, the process proceeds from step S401 to step S404, where a road automatic driving stable vehicle speed Vd1_μ corresponding to a road surface prone to slipping is calculated. The road automatic driving stable vehicle speed Vd1_μ when the yaw rate gain is below a certain value is calculated as a vehicle speed at which an appropriate yaw angle can be obtained for the steering angle. For example, a mapping is set so that the smaller the reduction rate of the yaw rate gain, the lower the vehicle speed, and the road automatic driving stable vehicle speed Vd1_μ is calculated with reference to the mapping.

[0094] On the other hand, when the yaw rate gain relative to the steering angle exceeds a certain value in step S401, the process proceeds from step S401 to step S402 to check whether the ABS is operating during the deceleration control. When the ABS is operating during the deceleration control, the road automatic driving stable vehicle speed Vd1 is calculated in step S404. Even if the yaw rate gain relative to the steering angle exceeds a certain value, the road automatic driving stable vehicle speed Vd1_μ when the ABS is operating during the deceleration control is calculated as the vehicle speed that obtains a predetermined deceleration when the ABS is not operating, for example, based on the ABS operating frequency.

[0095] In addition, in step S402, when the ABS is not working during the deceleration control process, the process proceeds from step S402 to step S403 to check whether the information of the road surface friction coefficient (road surface μ) can be obtained by inference or detection. If the information of the road surface μ cannot be obtained in step S403, the process returns to the main routine. If the information of the road surface μ can be obtained, the process proceeds to step S404 to calculate the road surface automatic driving stable vehicle speed Vd1_μ. The road surface automatic driving stable vehicle speed Vd1_μ at this time is calculated based on the obtained road surface μ.

[0096] Next, if we return to the main routine, after calculating the automatic driving stable vehicle speeds Vd1_w, Vd1_r, Vd1_s, and Vd1_μ for each scene in steps S1A to S1D, we proceed to step S2. In step S2, the driving control device 100 uses the lowest value of the automatic driving stable vehicle speed Vd1_w in crosswind, the automatic driving stable vehicle speed Vd1_r in rainy days, the automatic driving stable vehicle speed Vd1_s in snowfall, and the road automatic driving stable vehicle speed Vd1_μ as the automatic driving speed Vd1 (Vd1←min(Vd1_w, Vd1_r, Vd1_s, Vd1_μ)). Then, in step S3, the automatic driving speed Vd1 is compared with the set speed Vat of the second driving assistance mode to check whether the automatic driving speed Vd1 is lower than the set speed Vat.

[0097] In step S3, if Vd1≥Vat, since there is no particular hindrance to the current automatic driving based on the second driving assistance mode, the present process is exited and the automatic driving in the second driving assistance mode is continued. On the other hand, in step S3, if Vd1<Vat, since it is difficult to continue the second driving assistance mode under the current state, the process proceeds to step S4.

[0098] In step S4, the travel control device 100 requests the driver to select whether to continue the second driving assistance mode or to shift to the first driving assistance mode. Then, in step S5, it is checked whether the driver has steered the steering wheel and selected the first driving assistance mode.

[0099] When the driver chooses to shift to the first driving assistance mode and steers the steering wheel, the driving control device 100 reduces the level of automatic driving in step S6 and shifts from the second driving assistance mode to the first driving assistance mode. When shifting to the first driving assistance mode, the driver responds to the deterioration of the driving environment, so that the set vehicle speed Vat of the second driving assistance mode can be maintained.

[0100] On the other hand, if the driver chooses to continue the second driving assistance mode, the driving control device 100 reduces the vehicle speed of the second driving assistance mode to the vehicle speed Vd1 at which automatic driving is possible in step S7, thereby increasing the safety margin for maintaining the level of automatic driving in the second driving assistance mode in response to the deterioration of the driving environment, thereby continuing the second driving assistance mode.

[0101] Furthermore, the driving control device 100 checks in step S8 whether the driving environment further deteriorates during driving in the second driving assistance mode and the vehicle speed Vd1 that can be automatically driven is lower than the lower limit vehicle speed Vd2. Then, if Vd1 ≥ Vd2, the second driving assistance mode is maintained, and if Vd1 < Vd2, the automatic parking mode is switched to in step S9, so that the vehicle automatically stops at the roadside to ensure safety.

[0102] Thus, in this embodiment, the level of deterioration of the driving environment is evaluated during driving in the second driving assistance mode that does not require the driver to steer the steering wheel, and when the driving environment deteriorates, the second driving assistance mode can be continued by reducing the vehicle speed. In this way, the function of the automatic driving is uniquely limited or the driving assistance mode that requires the driver to steer the steering wheel is switched to avoid an increase in the burden on the driver, and the driving assistance mode that does not require the driver to steer the steering wheel can be continued to ensure the convenience of automatic driving.

Claims

1. A vehicle driving control system, characterized in that: The vehicle driving control system comprises: a manual driving mode; a first driving assistance mode for performing driving assistance control based on the premise that the driver steers the steering wheel; and a second driving assistance mode for performing driving assistance control without the driver steering the steering wheel, wherein the vehicle driving control system comprises: a vehicle speed calculation unit for automatically driving that monitors the driving environment including weather conditions, road conditions, and vehicle control conditions during driving in the second driving assistance mode, classifies scenes according to the weather conditions, road conditions, and vehicle control conditions, calculates an automatically driving stable vehicle speed at which the automatically driving can be stably performed for each of the scenes, and adopts the lowest vehicle speed among the calculated automatically driving stable vehicle speeds for each of the scenes as the vehicle speed at which the automatically driving can be continued in the second driving assistance mode; a driving assistance mode continuation determination unit, which compares the vehicle speed in the second driving assistance mode with the speed of the vehicle capable of automatic driving, and determines whether the driving assistance control based on the second driving assistance mode can be continued; as well as The driving assistance mode continuation unit reduces the vehicle speed of the second driving assistance mode to the vehicle speed at which the vehicle can be driven automatically, thereby enabling the driving assistance control based on the second driving assistance mode to be continued when the driving assistance mode continuation judgment unit determines that the driving assistance control based on the second driving assistance mode cannot be continued.

2. A vehicle driving control system, characterized in that: The vehicle driving control system comprises: a manual driving mode; a first driving assistance mode for performing driving assistance control based on the premise that the driver steers the steering wheel; and a second driving assistance mode for performing driving assistance control without the driver steering the steering wheel, wherein the vehicle driving control system comprises: a vehicle speed calculation unit for automatically driving that monitors a driving environment including a weather condition, a road surface condition, and a vehicle control condition during driving in the second driving assistance mode, classifies scenes according to the weather condition, the road surface condition, and the vehicle control condition, calculates an automatically driving stable vehicle speed at which the automatically driving can be stably performed for each of the scenes, and adopts the lowest vehicle speed among the calculated automatically driving stable vehicle speeds for each of the scenes as the automatically driving possible vehicle speed at which the second driving assistance mode can be continued as the automatically driving possible vehicle speed at which the second driving assistance mode can be continued; a driving assistance mode continuation determination unit, which compares the vehicle speed in the second driving assistance mode with the speed of the vehicle capable of automatic driving, and determines whether the driving assistance control based on the second driving assistance mode can be continued; a driving assistance mode selection unit for enabling selection of either continuing the second driving assistance mode or shifting to the first driving assistance mode when the driving assistance mode continuation determination unit determines that the driving assistance control based on the second driving assistance mode cannot be continued; as well as The driving assistance mode continuing unit enables the driving assistance control based on the second driving assistance mode to be continued by reducing the vehicle speed of the driving assistance mode to the vehicle speed at which the automatic driving is possible when the second driving assistance mode is selected to be continued by the driving assistance mode selecting unit.

3. The vehicle driving control system according to claim 2, characterized in that: When the driving assistance mode selection unit detects that the driver is steering the steering wheel, it is determined that the first driving assistance mode is selected, and the mode is shifted from the second driving assistance mode to the first driving assistance mode.

4. The vehicle driving control system according to claim 1 or 2, characterized in that: When the vehicle speed at which the automatic driving is possible is lower than a predetermined lower limit vehicle speed, the driving assistance mode continuing unit shifts to the manual driving mode or an automatic parking mode for automatically stopping the vehicle at a safe place.

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