Vehicle driving assistance systems

Abstract

To provide a driving support device of a vehicle that maintains a vehicle in normal travelling behavior and warns a driver of deterioration in arousal level when detecting the deterioration in arousal lever of the driver.SOLUTION: A driving support device comprises a front environment recognition device, a control device that performs preceding vehicle following control and lane center maintenance control, an electric power steering device 50, and a driver monitoring system. The control device, when the driver monitoring system detects deterioration in arousal level of a driver, executes the preceding vehicle following control and the lane center maintenance control, and stops ganged control of a turning angle of a turning wheel by the electric power steering device in accordance with a steering angle input from a steering wheel so as to make the steering wheel run idly.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a driving support device for a vehicle having a lane center maintenance function and a following vehicle following function.

Background Art

[0002] In recent years, in vehicles such as automobiles, a driving support device for assisting a driver's driving operation has been put into practical use for the purpose of reducing the burden of the driver's driving operation and improving safety.

[0003] Such a driving support device includes, for example, a manual driving mode in which steering and acceleration / deceleration are performed according to the driver's main driving operation, a driving support mode in which steering support control and acceleration / deceleration control are performed on the premise of the driver's main driving operation, and a driving support mode for running the vehicle without requiring the driver's driving operation (so-called, automatic driving mode).

[0004] The driving support control in each driving support mode is specifically realized by including a following vehicle distance control (ACC: Adaptive Cruise Control) function, a lane center maintenance control (ALKC: Active Lane Keep Centering) function, and the like. And, by such driving support control, the vehicle can be automatically driven along the traveling lane while maintaining the vehicle distance from the preceding vehicle.

[0005] In addition to these controls, among the driving support control devices of a vehicle, as a control for further enhancing safety, for example, Patent Document 1 discloses a technique for increasing the weight of steering together with braking when the driver's arousal level is low.

[0006] As described above, the conventional driving support control device controls the vehicle control unit so that the effect of the steering becomes heavy, and thus a large force is required when operating the steering, so that the driver can notice that his / her driving ability has decreased. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2009-101714 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, conventional driver assistance control systems, which increase the steering resistance based on the driver's alertness level to inform the driver that their driving ability has declined, have a problem in that the change in steering resistance is limited to a degree that does not interfere with the driver's steering, making it insufficient as a warning.

[0009] Therefore, in view of the above problems, the present invention aims to provide a vehicle driving assistance device that, when a decrease in the driver's level of alertness is detected, maintains the normal driving behavior of the vehicle and alerts the driver to the decrease in their level of alertness. [Means for solving the problem]

[0010] A vehicle driving assistance system according to one aspect of the present invention comprises: a forward environment recognition device that recognizes the driving environment in front of the vehicle; a control device that performs preceding vehicle following control and lane centering control based on the driving environment recognized by the forward environment recognition device; an electric power steering device that synchronizes control of the steering angle of the steering wheels according to the steering angle input by the steering wheel; and a driver monitoring system that detects changes in the driver's biological information. The control device, when the driver monitoring system detects that the driver's level of alertness has decreased and lane markings cannot be recognized, executes an escape mode in which the vehicle is stopped on the roadside; and when the driver monitoring system detects that the driver's level of alertness has decreased and lane markings can be recognized, executes the preceding vehicle following control and lane centering control, and executes a steering wheel slip mode in which the synchronized control of the steering angle according to the steering angle by the electric power steering device is stopped. [Effects of the Invention]

[0011] According to the present invention, when a decrease in the driver's level of alertness is detected, it is possible to provide a vehicle driving assistance device that maintains the normal driving behavior of the vehicle and alerts the driver to the decrease in their level of alertness. [Brief explanation of the drawing]

[0012] [Figure 1] Overall configuration diagram of the vehicle's driver assistance system. [Figure 2] Diagram illustrating the monitoring areas of the stereo camera, radar, and forward sonar. [Figure 3] Schematic diagram showing the configuration of the electric power steering system and driver monitoring system. [Figure 4] A flowchart illustrating an example of control performed by a vehicle's driver assistance system. [Figure 5] Schematic diagram showing the vehicle and steering wheel. [Figure 6] Plan view showing the steering handle in oscillating mode. [Modes for carrying out the invention]

[0013] An embodiment of one aspect of the present invention will be described in detail below with reference to the drawings. In the drawings used in the following description, the scale of each component is different in order to make each component recognizable on the drawing, and the present invention is not limited to the number of components, the shape of the components, the ratio of the sizes of the components, and the relative positional relationship of each component as shown in these drawings.

[0014] The embodiments of the present invention will be described below with reference to the drawings. The drawings relate to one embodiment of the present invention, and Figure 1 is an overall configuration diagram of the driver assistance device.

[0015] As shown in Figure 1, the driver assistance device 1 is configured to include, for example, a camera unit 10, which is a forward environment recognition device, fixed to the upper center of the front part of the interior of the vehicle (own vehicle) M.

[0016] This camera unit 10 is composed of a stereo camera 11, an image processing unit (IPU) 12, an image recognition unit (image recognition ECU) 13, and a main control unit (main ECU) 14, which is the main driving control device.

[0017] The stereo camera 11, which is a forward-facing environment recognition camera, has a main camera 11a and a sub-camera 11b. The main camera 11a and the sub-camera 11b are, for example, positioned symmetrically on either side of the center in the vehicle width direction. The main camera 11a and the sub-camera 11b are, for example, made of CMOS and stereo image the driving environment of the area Af (see Figure 2) in front of the vehicle from different viewpoints at predetermined imaging periods synchronized with each other.

[0018] The IPU 12 processes the driving environment image captured by the stereo camera 11 in a predetermined manner, and detects the edges of various objects such as solid objects represented on the image and lane lines on the road surface. Then, the IPU 12 obtains distance information from the amount of positional deviation of corresponding edges in the left and right images, and generates image information (distance image information) including the distance information.

[0019] Based on the distance image information and the like received from the IPU 12, the image recognition ECU 13 obtains the road curvature [1 / m] of the lane lines that demarcate the left and right sides of the road (the host vehicle's driving road), and the width between the left and right lane lines (lane width).

[0020] There are various known methods for obtaining this road curvature and lane width. For example, the image recognition ECU 13 recognizes the left and right lane lines by performing binarization processing based on the luminance difference on the basis of the driving environment information, and obtains the curvature of the left and right lane lines for each predetermined section using a curve approximation formula by the method of least squares. Further, the image recognition ECU 13 calculates the lane width from the difference in the curvatures of the left and right lane lines.

[0021] Then, the image recognition ECU 13 calculates, based on the curvatures of the left and right lane lines and the lane width, the vehicle lateral position deviation, which is the distance from the center of the lane to the center in the vehicle width direction of the vehicle M, and the like.

[0022] In addition, the image recognition ECU 13 performs predetermined pattern matching or the like on the distance image information, and recognizes solid objects such as guardrails, curbstones, and surrounding vehicles that extend along the road.

[0023] Here, in the recognition of solid objects by the image recognition ECU 13, for example, recognition of the type of solid object, the height of the solid object, the distance to the solid object, the speed of the solid object, the relative speed Vrel between the solid object and the vehicle M, and the like is performed.

[0024] The various types of information recognized by the image recognition ECU 13 are output to the main ECU 14 as driving environment information.

[0025] Thus, in this embodiment, the image recognition ECU 13, together with the stereo camera 11 and the IPU 12, functions as a driving environment recognition means for recognizing information about the driving environment outside the vehicle.

[0026] The main ECU14 is a control unit for the overall control of the driver assistance system 1.

[0027] This main ECU 14 is connected to various control units, including the cockpit control unit (CP_ECU) 21, the engine control unit (E / G_ECU) 22, the transmission control unit (T / M_ECU) 23, the brake control unit (BK_ECU) 24, and the power steering control unit (PS_ECU) 25, via in-vehicle communication lines such as CAN (Controller Area Network).

[0028] Furthermore, the main ECU14 is connected to various sensors, including a locator unit 36, a front environment recognition device consisting of a left front side sensor 41lf and a right front side sensor 41rf, and a rear environment recognition device consisting of a left rear side sensor 41lr and a right rear side sensor 41rr.

[0029] The CP_ECU21 is connected to the Human-Machine Interface (HMI)31, which is located around the driver's seat.

[0030] The HMI31 is comprised of, for example, switches for instructing the execution of various driving assistance controls, a mode switch for switching between driving assistance modes, a steering touch sensor 31a for detecting the driver's steering state, a driver monitoring system (DMS) 31b for detecting the driver's facial recognition and gaze, an alarm device 31c which is a warning device, a touch panel display, a combination meter, and a speaker.

[0031] When CP_ECU21 receives control signals from MONE_ECU14, it appropriately notifies the driver of various information such as warnings for the vehicle ahead, the status of driver assistance control implementation, and the driving environment of vehicle M, through displays and voice prompts via HMI31.

[0032] Furthermore, CP_ECU25 outputs various input information, such as the on / off status of various driver assistance controls, which are input by the driver via HMI31, to Main_ECU14.

[0033] The output side of the E / G_ECU22 is connected to the throttle actuator 32 of the electronically controlled throttle, among other things. The input side of the E / G_ECU22 is connected to various sensors, such as an accelerator sensor (not shown).

[0034] The E / G_ECU22 controls the throttle actuator 32 based on control signals from the main_ECU14 or detection signals from various sensors. This allows the E / G_ECU22 to adjust the amount of intake air for the engine and generate the desired engine output. The E / G_ECU22 also outputs signals such as the accelerator opening angle detected by the various sensors to the main_ECU14.

[0035] A hydraulic control circuit 33 is connected to the output side of T / M_ECU23. Various sensors, such as a shift position sensor (not shown), are connected to the input side of T / M_ECU23. Based on the engine torque signal estimated by E / G_ECU22 and detection signals from various sensors, T / M_ECU23 performs hydraulic control on the hydraulic control circuit 33. As a result, T / M_ECU23 operates friction engagement elements and pulleys in the automatic transmission to shift the engine output to the desired gear ratio.

[0036] Furthermore, the T / M_ECU23 outputs signals such as the shift position detected by various sensors to the main_ECU14.

[0037] The output side of the BK_ECU24 is connected to brake actuators 34, which adjust the brake fluid pressure output to the brake wheel cylinders located on each wheel. The input side of the BK_ECU24 is connected to various sensors, including a brake pedal sensor, yaw rate sensor, longitudinal acceleration sensor, and vehicle speed sensor (not shown).

[0038] The BK_ECU24 controls the brake actuator 34 based on control signals from the main_ECU14 or detection signals from various sensors. As a result, the BK_ECU24 generates appropriate braking force on each wheel to perform forced braking control and yaw rate control on the vehicle M.

[0039] Furthermore, the BK_ECU24 outputs signals such as brake operation status, yaw rate, longitudinal acceleration, and vehicle speed (own vehicle speed) detected by various sensors to the main_ECU14.

[0040] The output side of the PS_ECU25 is connected to an electric power steering motor 35, which applies steering torque to the steering mechanism through the motor's rotational force. Various sensors, such as a steering torque sensor and a steering angle sensor, are connected to the input side of the PS_ECU25.

[0041] The PS_ECU25 controls the electric power steering motor 35 based on control signals from the main_ECU14 or detection signals from various sensors. This allows the PS_ECU25 to generate steering torque for the steering mechanism.

[0042] Furthermore, the PS_ECU25 outputs signals such as steering torque and steering angle detected by various sensors to the main_ECU14.

[0043] The locator unit 36 ​​is comprised of a GNSS sensor 37 and a high-precision road map database (road map DB) 38.

[0044] The GNSS sensor 37 determines the position of vehicle M (latitude, longitude, altitude, etc.) by receiving positioning signals transmitted from multiple positioning satellites.

[0045] The DB38 road map is a large-capacity storage medium such as an HDD, and it stores highly accurate road map information (dynamic maps). This DB38 road map contains lane data necessary for autonomous driving, such as lane width data, lane center position coordinate data, lane direction angle data, and speed limit data.

[0046] This lane data is stored at intervals of several meters for each lane on the road map. The road map database also holds information on various facilities and parking lots. For example, based on a request signal from the main ECU 14, the road map database 38 outputs road map information for a set range based on the vehicle's position determined by the GNSS sensor 37 as driving environment information to the main ECU 14.

[0047] Thus, in this embodiment, the road map DB38, together with the GNSS sensor 37, functions as a driving environment recognition means for recognizing information about the driving environment outside the vehicle.

[0048] The left front side sensor 41lf and the right front side sensor 41rf are composed of sensors such as LiDAR (Light Detection and Ranging) and millimeter-wave radar. These left front side sensor 41lf and the right front side sensor 41rf are, for example, located on the left and right sides of the front bumper, respectively.

[0049] The left front side sensor 41lf and the right front side sensor 41rf detect three-dimensional objects as driving environment information in the areas Alf and Arf (see Figure 2) to the left and right front and sides of the vehicle M, which are difficult to recognize with the image from the stereo camera 11.

[0050] Alternatively, the left front side sensor 41lf and the right front side sensor 41rf may be omitted, and a single LiDAR sensor capable of detecting a wide range of areas in front, diagonally in front of both sides, and to the sides may be provided. Furthermore, in addition to the left front side sensor 41lf and the right front side sensor 41rf, a further LiDAR sensor capable of detecting a wide range of areas in front, diagonally in front of both sides, and to the sides may be provided.

[0051] The left rear side sensor 41lr and the right rear side sensor 41rr are composed of LiDAR sensors, millimeter-wave radar, etc. These left rear side sensor 41lr and the right rear side sensor 41rr are, for example, located on the left and right sides of the rear bumper, respectively.

[0052] The left rear side sensor 41lr and the right rear side sensor 41rr detect three-dimensional objects in the left and right diagonal side and rear areas Alr and Arr (see Figure 2) of the vehicle M, which are difficult to recognize with the left front side sensor 41lf and the right front side sensor 41rf, as driving environment information.

[0053] Here, each radar primarily detects three-dimensional objects, such as vehicles traveling alongside, by analyzing reflected light or reflected waves from the object. Specifically, each radar detects information about the three-dimensional object, including its width, the position of a representative point of the object (relative position to vehicle M), and its speed.

[0054] Thus, in this embodiment, the left front side sensor 41lf, the right front side sensor 41rf, the left rear side sensor 41lr, and the right rear side sensor 41rr function as driving environment recognition sensors that recognize information about the driving environment outside the vehicle. The left front side sensor 41lf and the right front side sensor 41rf also constitute forward environment recognition sensors.

[0055] Furthermore, the coordinates of each object outside the vehicle are all converted in the main_ECU14 to coordinates in a three-dimensional coordinate system with the center of the vehicle M as the origin. The coordinates of each object outside the vehicle are included in the driving environment information recognized by the image recognition_ECU13, the driving environment information recognized by the locator unit 36, the driving environment information recognized by the left front side sensor 41lf, the driving environment information recognized by the right front side sensor 41rf, the driving environment information recognized by the left rear side sensor 41lr, the driving environment information recognized by the right rear side sensor 41rr, and so on.

[0056] The main ECU14 has settings for the following driving modes: manual driving mode, a first driving control mode and a second driving control mode, and a evacuation mode. Each of these driving modes can be selectively switched in the main ECU14 based on, for example, the operation status of the mode switching switch provided on the HMI31.

[0057] Here, manual driving mode refers to a driving mode that requires steering by the driver, and is a driving mode in which the vehicle M is driven according to driving operations such as steering, accelerating, and braking by the driver.

[0058] Similarly, the first driving control mode is a driving mode that requires the driver to maintain steering. In other words, the first driving control mode is a semi-autonomous driving mode that, while reflecting the driver's driving operations, primarily uses adaptive cruise control (ACC), active lane keep centering (ALKC), and active lane departure prevention (ALKB) controls in appropriate combinations to drive the vehicle M along the target driving path, for example, through the control of E / G_ECU22, BK_ECU24, and PS_ECU25.

[0059] Here, the preceding vehicle following control is basically performed based on the driving environment information input from the image recognition ECU13. In other words, the preceding vehicle following control is performed based on, for example, the preceding vehicle information included in the driving environment information from the image recognition ECU13.

[0060] Furthermore, lane centering control and lane departure prevention control are basically performed based on driving environment information input from at least one of the image recognition ECU 13 or the locator unit 36. In other words, lane centering control and lane departure prevention control are performed based, for example, on lane marking information included in the driving environment information from the image recognition ECU 13 or the locator unit 36.

[0061] Furthermore, the second driving control mode is an automated driving mode that drives vehicle M according to a target route (route map information) without requiring steering, acceleration, or braking by the driver. This is achieved primarily by appropriately combining preceding vehicle following control, lane centering control, and lane departure prevention control through the control of, for example, E / G_ECU22, BK_ECU24, PS_ECU25, etc.

[0062] Retirement Avoidance The mode is, for example, the MRM (Minimum Risk Maneuver) mode, which automatically stops the vehicle M by illuminating its hazard lights and moving it to the roadside or elsewhere if, while driving in the second driving control mode, it becomes impossible to continue driving in that mode and it is not possible to take over driving operations to the driver.

[0063] Transferring driving control to the driver means, for example, transitioning to manual driving mode or the first driving control mode.

[0064] Thus, Avoidance The MRM (Manual Ramming Mode) is a control mode that safely stops vehicle M when the system cannot take over driving of vehicle M due to reasons such as a decrease in the driver's alertness.

[0065] Next, the steering mechanism of the electric power steering system 50 will be described. As shown in Figure 3, the electric power steering system 50 has a steering mechanism section 51 and a steering mechanism section 52 that steers the steering wheels 16R and 16L. The steering mechanism section 51 receives steering input from the steering wheel 15 that is maintained by the driver.

[0066] The electric power steering system 50 has a steering mechanism 51 and a steering wheel mechanism 52 that are separate (linkless), and is controlled in conjunction with each other by the ST_ECU 25, thereby realizing a so-called steer-by-wire system in which there is no mechanical connection between the steering wheel 15 and the steering wheels 16R, 16L.

[0067] The steering mechanism 51 comprises a steering handle 15, a steering shaft 53 connected to the steering handle 15, and a reaction motor 54 as a means of applying resistance, which is coaxially incorporated into the steering shaft 53.

[0068] The reaction motor 54 is driven and controlled by the ST_ECU25. The driving force of the reaction motor 54 is transmitted to the steering wheel 15 via the steering shaft 53.

[0069] The steering mechanism 52 comprises a rack shaft 18 extending in the left-right direction of the vehicle body, and knuckle arms 20R and 20L connected to both ends of the rack shaft 18 via tie rods 19R and 19L, respectively. Each knuckle arm 20R and 20L is connected to a steering wheel 16R and 16L, respectively.

[0070] The rack shaft 18 is supported via the housing 26 so as to be movable in the left-right direction of the vehicle M. A rack gear 18a is provided on this rack shaft 18.

[0071] A pinion gear 27a is meshed with the rack gear 18a. A pinion shaft 27 is connected to the pinion gear 27a.

[0072] A power steering motor 35, which is the steering motor, is coaxially integrated into the middle of the pinion shaft 27. The power steering motor 35 is driven and controlled by the ST_ECU25.

[0073] The driving force of the electric power steering motor 35 is transmitted to the rack shaft 18 via the pinion shaft 27, pinion gear 27a, and rack gear 18a. This causes the steering wheels 16R and 16L to turn.

[0074] A clutch mechanism 40 is interposed between the steering shaft 53 and the pinion shaft 16. This clutch mechanism 40 is engaged and disengaged by the ST_ECU 25 in the event of a malfunction (failure) of the reaction motor 54 or the electric power steering motor 35.

[0075] The ST_ECU25 is connected to a steering angle sensor 54a, a steering torque sensor 54b, a wheel angle sensor 18b, a reaction force torque sensor 35a, and other sensors.

[0076] The steering angle sensor 54a detects the steering angle of the steering wheel 15 as controlled by the driver. The steering torque sensor 54b detects the steering torque of the steering wheel 15 as controlled by the driver. The steering wheel 15 is also equipped with a steering touch sensor 31a.

[0077] The wheel angle sensor 18b detects the steering angle (wheel angle) of the steering wheels 16R and 16L. The reaction torque sensor 35a detects the reaction torque from the road surface to the steering wheels 16R and 16L.

[0078] The ST_ECU25 then drives and controls the reaction motor 54 and the electric power steering motor 35 in a predetermined relationship based on the inputs from these sensors. In other words, the ST_ECU25 controls the linkless steering mechanism 51 and the steering mechanism 52 in conjunction (steer-by-wire control) based on a set arbitrary relationship.

[0079] Furthermore, the DMS31b is equipped with an in-car camera 30. This in-car camera 30 is built into the instrument panel center visor or similar and recognizes the driver's face.

[0080] The DMS31b receives driver information, including driver status such as drowsiness, dozing off, and distracted driving, based on facial recognition and gaze patterns captured by the in-car camera 30. This driver information is output from the DMS31b to the CP_ECU21.

[0081] As will be explained in more detail later, the driver assistance device 1 configured as described above will stop the coordinated control between the steering mechanism 51 and the steering control mechanism 52 when it detects a decrease in the driver's level of alertness, until it detects a recovery in the driver's level of alertness.

[0082] The driver assistance device 1 then executes a second driving control mode, which is an automated driving mode that drives vehicle M according to the driving route by appropriately combining the preceding vehicle following control, lane centering control, and lane departure prevention control.

[0083] In this embodiment, a decrease in the driver's alertness is detected from the following states.

[0084] The driver assistance device 1 continuously detects the amount of movement of the vehicle M in the vehicle width direction based on the relationship between the vehicle M's position and the road surface. By frequency-converting the detected amount of movement, it obtains the power of each frequency component, and based on the power of each frequency component, a decrease in the driver's alertness is monitored and detected by the main ECU 14. Since this detection of a decrease in the driver's alertness is a well-known technique, a detailed explanation is omitted.

[0085] Furthermore, in addition to detection based on vehicle behavior as described above, a decrease in the driver's alertness is detected by the main ECU 14 by monitoring changes in biometric information such as the driver's gaze direction, blinking, and eyelid opening / closing state, captured by the in-vehicle camera 30 of the DMS 31b.

[0086] Furthermore, a decrease in the driver's level of alertness may be detected by installing vital sensors in the DMS31b, the driver's seat, or a wirelessly controlled wristwatch to monitor and detect changes in the driver's vital information, such as heart rate, autonomic nervous system activity, electroencephalogram (EEG), or skin potential activity.

[0087] Alternatively, a decrease in the driver's alertness may be detected by the main ECU 14 by monitoring the strength of the steering wheel 15 gripped by the driver through the detection of the steering touch sensor 31a.

[0088] The main ECU14 may comprehensively evaluate the various detection results described above to determine if the driver's level of alertness has decreased.

[0089] Next, an example of the control performed by the driver assistance device 1 based on the flowchart in Figure 4 will be described below.

[0090] The driver assistance system 1 acquires the driver's biometric information and the vehicle M's behavior information (S1) when the vehicle M is in motion. Here, the main_ECU14 acquires the driver's biometric information output to the CP_ECU21 from the DMS31b or the like. The main_ECU14 also acquires behavior information such as the continuous amount of movement of the vehicle M in the vehicle width direction.

[0091] Based on the driver's biometric information, the main ECU 14 determines whether the driver's level of alertness has decreased (S2). Here, the main ECU 14 determines the decrease in the driver's level of alertness based on changes in biometric information such as the driver's gaze direction, blinking, and eyelid opening / closing state, as well as the gripping force on the steering wheel 15 and the behavior of the vehicle M.

[0092] If the driver's alertness level decreases, the main ECU14 initiates a warning (S3). This warning involves the main ECU14 controlling the DMS31b via the CP_ECU21, which then issues a warning sound via the alarm device 31c, a speaker-based warning announcement, a warning display on the display and combination meter, and other forms of alert. The devices for the speaker-based warning announcement and the warning display on the display and combination meter are included in the warning device.

[0093] On the other hand, if the driver's alertness level has not decreased, the main ECU14 returns to step S1 and repeatedly performs the acquisition of the driver's biometric information.

[0094] After executing the warning in step S3, the main_ECU14 determines whether or not a preceding vehicle has been detected (S4). Here, the main_ECU14 determines the presence or absence of a preceding vehicle based on preceding vehicle information included in the driving environment information input from the image recognition_ECU13.

[0095] If a preceding vehicle is detected, the main ECU 14 starts following the preceding vehicle (S5). Here, the main ECU 14 causes vehicle M to follow the preceding vehicle while maintaining a predetermined distance, based on the driving environment information input from the image recognition ECU 13.

[0096] In step S4, if no preceding vehicle is detected, the main ECU14 determines whether or not it recognizes the lane markings (S6).

[0097] Here, the presence or absence of lane markings is determined based on lane marking information included in the driving environment information input from the image recognition ECU13 or the locator unit 36. If lane markings cannot be recognized, the main ECU14 proceeds to step S19, which will be described later.

[0098] In step S6,If lane markings are recognized, the main ECU14 starts lane centering control and lane departure prevention control in an appropriate combination (S7). That is, the main ECU14 executes the second driving control mode (autonomous driving control) described above, which does not require steering, acceleration, or braking by the driver.

[0099] Furthermore, when executing this second driving control mode, the main ECU14 sets the vehicle speed of vehicle M within the legal speed limit (S8). That is, if the vehicle speed of vehicle M exceeds the legal speed limit, the main ECU14 changes the set speed to the legal speed limit, and if it is below the legal speed limit, it sets the speed to that speed (it may also change it to the legal speed limit).

[0100] next The main ECU 14 then starts the steering wheel free-spinning mode (S9). Here, the main ECU 14, under the control of the ST ECU 25, stops the application of resistance to the steering shaft 53 by the reaction force motor 54, allowing the steering shaft 53 to become free (free-spinning), and also stops the linked control of the steering mechanism 51 and the steering turning mechanism 52.

[0101] As a result, the steering mechanism 51 becomes unable to receive steering input from the steering handle 15 connected to the steering shaft 53. The steering handle 15 then enters a state of free rotation without resistance.

[0102] In other words, as shown in Figure 5, even if the steering wheel 15 is turned to the right R or left L as indicated by the dashed line, the vehicle M will not, for example, make a right turn R or a left turn L as indicated by the dashed line, but will instead be controlled to follow the preceding vehicle or follow the driving path G indicated by the solid line along the route in the center of the lane.

[0103] Next, the main ECU 14 starts the steering wheel oscillation mode, which is a warning mode (S10). Here, the main ECU 14, under the control of the ST ECU 25, drives the reaction motor 54 to rotate the steering shaft 53 in small increments from side to side, as shown in Figure 6. As a result, the main ECU 14 oscillates the steering wheel 15 connected to the steering shaft 53, alerting the driver that the steering is not functioning due to a decrease in alertness.

[0104] In addition, the warning mode may be configured to cause the steering wheel 15 to vibrate. Such a mechanism control that alerts the driver through the swinging or vibration of the steering wheel 15 is included in the warning device.

[0105] The main ECU14 acquires the driver's biometric information again (S11). The main ECU14 determines from the driver's biometric information whether or not the driver's level of alertness has recovered (S12).

[0106] Here, the main ECU 14 acquires the driver's biometric information and determines whether the driver's level of alertness has recovered based on changes in biometric information such as the driver's gaze direction, blinking, and eyelid opening / closing state, as well as the gripping force on the steering wheel 15.

[0107] If the driver's alertness level recovers, the main ECU14 stops the warnings (S13). At this point, warnings such as the warning sound from the HMI31's alarm device 31c, the announcement warning from the speaker, and the alerts displayed on the display and combination meter are stopped.

[0108] Then, the steering wheel oscillation mode is stopped (S14), and the steering wheel free-spinning mode is stopped (S15). The main ECU 14 stops the oscillation drive of the reaction force motor 54 controlled by the ST ECU 25, and restores the application of resistance to the steering shaft 53 by the reaction force motor 54.

[0109] In response to this, the main ECU 14 restores the steering angle of the steering wheel 15 to match the steering angles of the steering wheels 16R and 16L (S16). Here, the main ECU 14 drives the reaction motor 54 to restore the steering angle of the steering wheel 15, detected by the steering angle sensor 54a, to match the steering angles (wheel angles) of the steering wheels 16R and 16L, detected by the wheel angle sensor 18b input to the ST ECU 25. This restores the interlocking control between the steering mechanism 51 and the steering mechanism 52.

[0110] Furthermore, if the steering angle (wheel angle) of the steering wheels 16R and 16L differs significantly from the steering angle of the steering wheel 15, the main ECU 14 will not rapidly rotate the steering wheel 15 to return it to its original position, but will rotate it gradually or in stages to return it to an angle that matches the steering angle (wheel angle).

[0111] Then, the main ECU14 terminates the automatic driving control for the second driving control mode and hands it over to the driver (S17), returning to step S1.

[0112] If the driver's alertness has not recovered in step S12, the main ECU 14 determines whether a predetermined time has elapsed (S18). Step S12 returns to step S11 and the routine is repeatedly executed until the predetermined time has elapsed.

[0113] If the driver's alertness does not recover after the predetermined time in step S12, the main ECU 14 starts the aforementioned escape mode (MRM) (S19). In this mode, the main ECU 14 automatically stops the vehicle M to the roadside or elsewhere, activating the hazard lights. Then, the main ECU 14 stops the warning (S20) and terminates the control routine.

[0114] Furthermore, in step S6, if lane markings are not recognized... ,vinegar The Step S19's retreat mode (MRM) is activated.

[0115] As described above, when the driver assistance system 1 of vehicle M recognizes that the driver's alertness level has decreased, it switches the vehicle M's driving control to automatic (second driving control mode), disengages the steer-by-wire control of the electric power steering system 50, and causes the steering wheel 15 to spin freely. In this way, the driver assistance system 1 of vehicle M prevents the driver from steering, maintaining the vehicle M's driving behavior normally while performing control to alert the driver to the decrease in alertness level.

[0116] Furthermore, the driver assistance system 1 of vehicle M alerts the driver to a decrease in alertness by shaking the steering wheel 15. When the driver assistance system 1 of vehicle M recognizes that the driver's alertness has recovered to a normal state, it returns the steering wheel 15 to a state where a reaction torque is applied. In other words, the driver assistance system 1 of vehicle M restores the steer-by-wire control of the electric power steering system 50, returning the vehicle M to a state where the driver can manually drive it.

[0117] Furthermore, when the driver assistance system 1 of vehicle M transfers control authority for various aspects of vehicle M from the system to the driver, an intermediate state (Shared Control) may be included.

[0118] Specifically, as part of Shared Control, for example, when the steering wheel 15 returns from a free-spinning mode to a normal state where steering input is possible, the system applies rotational torque from the reaction motor 54 to ensure that the steering angle of the steering wheel 15 matches the steering angle (wheel angle) of the steering wheels 16R and 16L, thereby performing return support control in addition to the driver's steering return.

[0119] Furthermore, when executing the free-spinning mode in which the steering wheel 15 is free-spinned, it is necessary to instantly stop the driver's operation, so it is desirable to disable the Shared Control function in the vehicle M's driver assistance system 1.

[0120] In this embodiment, an electric power steering system 50 using a steer-by-wire system is exemplified, which includes a steering mechanism 51 to which the steering angle of the steering wheel 15 is input, and a steering mechanism 52 to which the steering wheels 16R and 16L are steered. However, the system is not limited to this, and a clutch mechanism may be provided on the steering shaft of a general steering mechanism to interrupt the transmission of rotational force from the steering shaft and allow the steering wheel 15 to rotate freely.

[0121] Furthermore, when the steering steering device 1 of vehicle M needs to return the steering angle of the steering wheel 15 to the steering angle (wheel angle) of the steering wheels 16R and 16L, if a large reaction torque is required to return the steering wheel 15, the device may, for example, make an audio announcement requesting the driver to temporarily release their hands from the steering wheel 15 and then requesting them to grip the steering wheel 15 again after the return.

[0122] Each of the ECUs 13, 14, 21-25 of the vehicle M's driver assistance system 1 has a processor that includes a central processing unit (CPU), memory devices such as ROM and RAM. Furthermore, all or some of the configurations of the processor's multiple circuits may be executed by software. For example, the CPU may read and execute various programs corresponding to each function stored in the ROM.

[0123] Furthermore, all or part of the processor's functions may be comprised of logic circuits or analog circuits, and the processing of various programs may be implemented using electronic circuits such as FPGAs.

[0124] The inventions described in the above embodiments are not limited to those forms, and various modifications can be made in the implementation stage without departing from the gist of the invention. Furthermore, each of the above embodiments includes inventions at various stages, and various inventions can be extracted by appropriate combinations of the multiple constituent elements disclosed.

[0125] For example, if the problem described can be solved and the effects described can be obtained even if some of the constituent elements shown in each form are removed, then the configuration with the removed constituent elements can be extracted as an invention. [Explanation of Symbols]

[0126] 1…Driving assistance system 10…Camera unit 11…Stereo camera 11a...Main camera 11b... Sub-camera 13…Image recognition unit 14…Main Control Unit 15… Steering wheel 15... Steering wheel 16...Pinion shaft 16R,16L…Steered wheel 18... Rack axis 18a... Rack gear 18b... Wheel angle sensor 19R, 19L... Tie rod 20R, 20L... Knuckle arm 21…Cockpit control unit 22…Engine control unit 23…Transmission control unit 24…Brake control unit 25…Power steering control unit 26… Housing 27...Pinion shaft 27a... Pinion gear 30...In-car camera 31a... Steering touch sensor 31b…Driver Monitoring System 31c…Alarm device 32… Throttle Actuator 33... Hydraulic control circuit 34…Brake actuator 35…Electric power steering motor 35a... Reaction force torque sensor 36...Locator Unit 37…GNSS sensor 38…High-precision road map database 40...Clutch mechanism 41lf... Left front side sensor 41lr... Left rear side sensor 41rf...Right front side sensor 41rr...Right rear side sensor 50…Electric power steering system 51... Steering mechanism 52... Steering mechanism 53... Steering shaft 54… Reaction motor 54a... Steering angle sensor 54b... Steering torque sensor M... Vehicle (Own vehicle)

Claims

1. A forward-facing environment recognition device that recognizes the driving environment in front of the vehicle, A control device that performs preceding vehicle following control and lane centering control based on the driving environment recognized by the forward environment recognition device, An electric power steering system that controls the steering angle of the steering wheels in conjunction with the steering angle input by the steering wheel, A driver monitoring system that detects changes in the driver's biometric information, Equipped with, The control device is When the driver monitoring system detects that the driver's level of alertness has decreased, and the lane markings cannot be recognized, it executes an evacuation mode in which the vehicle is pulled over to the roadside. A vehicle driving assistance device characterized in that, when the driver monitoring system detects that the driver's level of alertness has decreased, and the lane markings are recognizable, it executes the preceding vehicle following control and the lane centering control, and executes a steering wheel slip mode which stops the linked control of the steering angle according to the steering angle by the electric power steering device.

2. The vehicle driving assistance device according to claim 1, characterized in that when the control device is executing the steering wheel slip mode, the driver monitoring system detects that the driver's level of alertness has decreased, and the control device drives the electric power steering device to execute a warning mode that causes the steering wheel to shake or vibrate.

3. The control device further includes a warning device that warns the driver, When the driver monitoring system detects that the driver's level of alertness has decreased, it activates the warning device. The vehicle driving assistance device according to claim 1 or 2, characterized in that, while the steering wheel slippage mode is being executed, when the driver monitoring system detects that the driver's level of alertness has recovered, the warning device is deactivated, the linked control of the steering angle of the steering wheels in accordance with the steering angle of the electric power steering system is restored, and the preceding vehicle following control and the lane centering control are terminated.

4. The vehicle driving assistance device according to claim 3, characterized in that the control device executes the escape mode if the driver's level of alertness does not recover even after a predetermined time has elapsed while the steering wheel slip mode is being executed.

5. The electric power steering device is a steer-by-wire type device equipped with a steering mechanism and a turning mechanism, as described in any one of claims 1 to 4, which is a driving assistance device for a vehicle.

Images