Vehicle control device

Abstract

A travel control unit 26 determines switching from an automatic driving mode to a manual driving mode on the basis of a prescribed condition. At such time, the travel control unit 26 selects, from among a plurality of types of travel control, a specific travel control to be added to the manual driving mode, said selection being made in accordance with a state of an occupant before switching to the manual driving mode.

Description

Vehicle control device

[0001] The present invention relates to a vehicle control device having an automatic driving control function.

[0002] In recent years, in the field of vehicle control devices, many technologies related to automatic driving control that do not require the intervention of a driver's driving operation have been proposed.

[0003] Such a vehicle control device can shift the vehicle control mode from the automatic driving mode to the manual driving mode according to preset conditions. For example, in Japanese Patent Application Laid-Open No. 2020-44938, when an abnormality determination unit determines an abnormal state of a disturbance to the host vehicle, such as a failure of the host vehicle, the occurrence of a large yaw rate, a rapid change in the yaw rate, or an obstacle such as a dropped object on the road, the execution of the automatic driving mode is avoided and a technique for executing a switch to the manual driving mode is disclosed. Further, Japanese Patent Application Laid-Open No. 2020-44938 discloses a technique for performing drive force distribution based on the steering amount during automatic driving when switching to the manual driving mode to prevent a sudden steering operation by the driver from being reflected in the behavior of the vehicle.

[0004] However, the technique disclosed in Japanese Patent Application Laid-Open No. 2020-44938 uniformly restricts the intervention of the driving operation when switching to the manual driving mode regardless of the state of the driver. Therefore, it becomes difficult to reflect the driver's intention in the behavior of the vehicle.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a vehicle control device that can accurately reflect the driver's intention in the behavior of the vehicle while ensuring appropriate running performance after switching from the automatic driving mode to the manual driving mode.

[0006] A vehicle control device according to one aspect of the present invention is a vehicle control device that can switch between an automatic driving mode that does not require driver operation and a manual driving mode that requires driver operation as the driving mode of the vehicle, and comprises: detection means for detecting the state of occupants riding in the vehicle; driving control means for performing a plurality of types of driving control on the vehicle; first determination means for determining a switch from the automatic driving mode to the manual driving mode; and second determination means for selecting a specific driving control to be added to the manual driving mode from among the plurality of types of driving control, according to the state of the occupants before switching to the manual driving mode.

[0007] Schematic diagram of the vehicle control system Flowchart showing the driving mode switching control routine (Part 1) Flowchart showing the driving mode switching control routine (Part 2) Flowchart showing the additional processing subroutine for driving control

[0008] The present invention will be described below with reference to the illustrated embodiments. The drawings used in the following description are schematic, and in order to show each component at a size that can be recognized on the drawing, the dimensional relationships and scales of each component may differ for each component. Therefore, the present invention is not limited to the illustrated forms with respect to the quantity of each component, the shape of each component, the ratio of the sizes of each component, and the relative positional relationships of each component as shown in each drawing.

[0009] One embodiment of the present invention, the vehicle control device 1, is mounted on a vehicle such as an automobile (the vehicle itself). This vehicle control device 1 performs various driving controls on the vehicle itself.

[0010] First, the schematic configuration of the vehicle control device 1 of one embodiment of the present invention will be described below using the block diagram in Figure 1.

[0011] As shown in Figure 1, the vehicle control device 1 of this embodiment comprises a locator unit 11, a camera unit 21, a surrounding area monitoring unit 22, and a driving control unit 26.

[0012] Here, the locator unit 11, camera unit 21, and surrounding monitoring unit 22 are component units that function as a driving environment recognition device for recognizing the external driving environment, including objects in front of and around the vehicle. Each of these units 11, 21, and 22 exists as a completely independent component unit, without depending on each other.

[0013] The locator unit 11 estimates the position of the vehicle on the road map (vehicle position). Furthermore, the locator unit 11 acquires road map information, etc., mainly in front of the estimated vehicle position.

[0014] The locator unit 11 includes a map locator calculation unit 12 and a high-precision road map database 17 (road map DB) as a map information storage unit.

[0015] The map locator calculation unit 12 includes a vehicle position estimation calculation unit 12a and a driving route setting calculation unit 12b.

[0016] The vehicle position estimation calculation unit 12a performs calculations to estimate the vehicle's position. Based on the positioning signal received by the GNSS receiver 13 (described later), the vehicle position estimation calculation unit 12a acquires the vehicle's current position coordinates (latitude and longitude), and maps these position coordinates onto map information to estimate the vehicle's position (current position) on the road map.

[0017] Furthermore, the vehicle position estimation calculation unit 12a identifies the vehicle's driving lane, acquires road shapes such as driving lanes and merging lanes stored in the map information, and stores them sequentially.

[0018] Furthermore, the vehicle position estimation calculation unit 12a can also perform vehicle position estimation using autonomous navigation based on various data acquired by the autonomous driving sensor 14 (described later). Such vehicle position estimation using autonomous navigation is performed, for example, in situations where the sensitivity of the GNSS receiver 13 is reduced and it is not possible to receive effective positioning signals from positioning satellites, such as when driving in a tunnel.

[0019] The driving route setting calculation unit 12b performs calculations to set a driving route from the vehicle's current position to the destination (and waypoints). Based on the vehicle's position information (latitude, longitude) estimated by the vehicle position estimation calculation unit 12a and the location information (latitude, longitude) of the destination and waypoints input from the route information input device 15 (described later), the driving route setting calculation unit 12b refers to the local dynamic map stored in the high-precision road map database 17. The driving route setting calculation unit 12b then constructs a driving route connecting the vehicle's current position and the destination on the local dynamic map of the high-precision road map database 17 according to pre-set route conditions.

[0020] In this way, the map locator calculation unit 12 maps the vehicle's position estimated by the vehicle position estimation calculation unit 12a onto a map to determine the vehicle's current location. The map locator calculation unit 12 also acquires road map information, including environmental information around the vehicle's current location. Furthermore, the map locator calculation unit 12 connects the input location coordinates (latitude, longitude) of the destination, etc., with the vehicle's position to construct the vehicle's target driving route (target driving route).

[0021] Furthermore, the map locator calculation unit 12 sets a target driving route for autonomous driving on the constructed target driving route, extending several kilometers ahead of the vehicle. The items set as the target driving route include the lane the vehicle will travel in, the timing of lane changes to overtake the preceding vehicle, and the timing of initiating lane changes.

[0022] The high-precision road map database 17 is mainly composed of large-capacity storage media such as HDDs (Hard Disk Drives) and SSDs (Solid State Drives). This high-precision road map database 17 stores well-known high-precision road map information (local dynamic maps). This high-precision road map information has the same layer structure as global dynamic maps provided on, for example, cloud servers (not shown). Specifically, the high-precision road map information has a layered structure in which additional map information necessary to support autonomous driving is superimposed on the lowest layer of static information that forms the basis.

[0023] Here, additional map information includes static location information such as road type, road shape, left and right lane markings, exits for expressways and bypasses, junctions, service areas, and the length of entrances and exits for diverging and merging lanes leading to parking areas. Furthermore, additional map information includes dynamic location information such as traffic congestion information and traffic restrictions due to accidents or construction.

[0024] When the map locator calculation unit 12 sets a target driving route, surrounding information necessary for autonomous driving of the vehicle along the set target driving route is continuously acquired from the global dynamic map, and additional map information is updated sequentially.

[0025] Furthermore, high-precision road map information also contains lane data necessary for autonomous driving, such as lane width data, lane center position coordinate data, lane direction angle data, and speed limit information. This lane data and other information are stored at intervals of several meters for each lane on the road map.

[0026] The map locator calculation unit 12 is connected to a GNSS receiver 13, an autonomous driving sensor 14, a route information input device 15, and an external communication device 16, among others.

[0027] The GNSS receiver 13 functions as a vehicle position acquisition unit and receives various information, for example, from the GNSS (Global Navigation Satellite System). This GNSS receiver 13 receives positioning signals transmitted from multiple positioning satellites. The GNSS receiver 13 outputs the acquired positioning signals to the map locator calculation unit 12 of the locator unit 11. The map locator calculation unit 12 estimates the vehicle's position (latitude and longitude) based on the positioning signals from multiple positioning satellites received by the GNSS receiver 13. Therefore, this GNSS receiver 13 is connected to the input side of the map locator calculation unit 12.

[0028] The autonomous driving sensor 14 is a group of sensors that enables autonomous driving in situations where the reception sensitivity from GNSS satellites is low and positioning signals cannot be effectively received, such as when driving in a tunnel. The autonomous driving sensor 14 is composed of, for example, a longitudinal acceleration sensor, a vehicle speed sensor, a gyroscope sensor, a yaw rate sensor, etc. Therefore, the map locator calculation unit 12 performs localization from the distance traveled and direction based on the vehicle speed detected by the vehicle speed sensor, the yaw rate (yaw angular velocity) detected by the yaw rate sensor, and the longitudinal acceleration detected by the longitudinal acceleration sensor, etc., and estimates the vehicle's position. For this reason, the autonomous driving sensor 14 is connected to the input side of the map locator calculation unit 12.

[0029] The route information input device 15 is a terminal device operated by personnel on board the vehicle, such as the driver or passengers. This route information input device 15 can collect and input a series of information necessary for setting the target driving route in the map locator calculation unit 12, such as setting the destination and waypoints (such as highway service areas).

[0030] The route information input device 15 is specifically an input unit of a car navigation system (e.g., a touch panel on a monitor), a mobile terminal such as a smartphone, or a personal computer. The route information input device 15 is connected to the map locator calculation unit 12 via a wired or wireless connection. As a result, when the driver or passenger operates the route information input device 15 to input destination and waypoint information (facility name, address, telephone number, etc.), that input information is read into the map locator calculation unit 12. The map locator calculation unit 12 sets the position coordinates (latitude, longitude) of the destination and waypoints input from the route information input device 15. Therefore, the route information input device 15 is connected to the input side of the map locator calculation unit 12.

[0031] The external communication device 16 communicates wirelessly with devices located outside the vehicle. Specifically, the external communication device 16 communicates with other vehicles traveling in the vicinity of the vehicle, for example. It also communicates with infrastructure installed along the roadside on which the vehicle is traveling, for example. Through these communications, the external communication device 16 acquires various information such as other vehicles ahead of the vehicle, accidents, traffic congestion, and weather conditions as driving environment information. The acquired driving environment information is superimposed on the lowest-level static information layer as dynamic additional map information necessary to support automated driving.

[0032] The camera unit 21 recognizes the driving environment in the direction of the vehicle's travel (mainly forward) and acquires and collects this information as driving environment data. Specifically, the camera unit 21 recognizes various landmarks and other objects present around the road on which the vehicle is traveling as driving environment data. The landmarks recognized by the camera unit 21 include, for example, other vehicles traveling in front of or to the side of the vehicle (such as preceding vehicles or vehicles traveling alongside), three-dimensional objects including pedestrians walking in front or attempting to cross in front, bicycles, motorcycles and other moving objects, traffic signals (lighting color, flashing state, arrow direction, etc.), road signs, stop lines, lane markings and other road markings. Furthermore, landmarks also include buildings, walls, sound barriers, guardrails, etc. adjacent to the road.

[0033] Therefore, the camera unit 21 is configured to include an in-vehicle camera (stereo camera) consisting of a main camera 21a and a sub-camera 21b, an image processing unit 21c (IPU; hereinafter referred to as IPU 21c), a forward driving environment recognition unit 21d, and the like.

[0034] The camera unit 21 is fixed to the upper center of the front part of the vehicle's interior. The main camera 21a and sub-camera 21b are positioned symmetrically on either side of the center in the width direction of the vehicle. The main camera 21a captures reference image data, and the sub-camera 21b captures comparison image data. The two image data acquired by these two cameras 21a and 21b are subjected to predetermined image processing by the IPU 21c.

[0035] Each camera 21a and 21b may also be equipped with a function to acquire sound information simultaneously with image information. In this case, the sound information acquired simultaneously with the image information is included in the forward driving environment information as sound information related to the forward driving environment of the vehicle.

[0036] The IPU 21c reads the reference image data and the comparison image data, and recognizes the same object (target) in both images. The IPU 21c also calculates the distance from the vehicle to the object (target) based on the parallax between the two images, using the principle of triangulation. The IPU 21c then outputs the image information, including the distance to the target, as distance image information to the forward driving environment recognition unit 21d.

[0037] The forward driving environment recognition unit 21d recognizes the driving environment information in front of the vehicle based on distance image information.

[0038] Forward driving environment information includes various types of information such as road shape of the path the vehicle is traveling on, lane width between lane markings on merging and diverging lanes leading to entrances and exits of expressways and bypasses, junctions, intersections, pedestrian crossings, traffic lights, road signs, and roadside obstacles (utility poles, telephone poles, parked vehicles, etc.). In addition, forward driving environment information also includes the lateral position deviation of the vehicle in the width direction relative to the center of the left and right lane markings in the driving lane the vehicle is traveling in.

[0039] Furthermore, the forward driving environment recognition unit 21d performs predetermined pattern matching on the distance image information. As a result, the forward driving environment recognition unit 21d recognizes guardrails, curbs, and various other three-dimensional objects along the road as forward driving environment information. In this recognition of three-dimensional objects by the forward driving environment recognition unit 21d, for example, the type of three-dimensional object, the distance to the three-dimensional object, the speed of the three-dimensional object, and the relative speed between the three-dimensional object and the vehicle are recognized.

[0040] In the vehicle control device 1 of the present embodiment, in addition to the camera unit 21, as an autonomous sensor as a detection means for detecting travel route information, for example, a radar device may be provided. Specifically, this radar device has an autonomous sensor as a detection means by various radars of sensing devices such as a millimeter-wave radar, a lidar (LIDAR: Light Detection and Ranging), and a laser radar.

[0041] The surrounding monitoring unit 22 recognizes the driving environment information around the host vehicle. The surrounding monitoring unit 22 includes a surrounding environment recognition sensor 22a, a surrounding driving environment recognition unit 22b, and the like.

[0042] The surrounding environment recognition sensor 22a is, for example, an autonomous sensor group as a sensing device such as an ultrasonic sensor, a millimeter-wave radar, a lidar (LIDAR; Light Detection and Ranging), a camera, and a surrounding environment detection means formed by combining these.

[0043] Specifically, for example, a plurality of millimeter-wave radars as the surrounding environment recognition sensor 22a are respectively arranged at the four corner portions of the vehicle (for example, the left front side, the right front side, the left rear side, the right rear side, etc.). Among these, the millimeter-wave radars on the left and right front sides are provided, for example, on the left and right side portions of the front bumper. The millimeter-wave radars on the left and right front sides are used to monitor a partial area around the vehicle (the area diagonally in front of and to the sides of the vehicle) that is difficult to recognize by the images acquired by the two cameras 21a and 21b of the camera unit 21.

[0044] Also, the millimeter-wave radars on the left and right rear sides are provided, for example, on the left and right side portions of the rear bumper. The millimeter-wave radars on the left and right rear sides are used to monitor a partial area around the vehicle (the area from the side to the rear of the vehicle) that cannot be monitored by the above-mentioned millimeter-wave radars on the left and right front sides.

[0045] The surrounding driving environment recognition unit 22b acquires surrounding environment information, which is information about moving objects (e.g., pedestrians, bicycles, motorcycles, accompanying vehicles, following vehicles traveling in the own lane or adjacent lanes, oncoming vehicles, etc.) around the host vehicle, based on the output signal from the surrounding environment recognition sensor 22a. Such moving objects include, for example, pedestrians, bicycles, motorcycles, accompanying vehicles, following vehicles, and oncoming vehicles.

[0046] The surrounding driving environment recognition unit 22b specifies moving targets such as pedestrians from the recognized objects. Further, the surrounding driving environment recognition unit 22b calculates the moving direction, moving speed, etc. of the specified target.

[0047] Here, the forward driving environment recognition unit 21d of the camera unit 21 and the surrounding driving environment recognition unit 22b of the surrounding monitoring unit 22 are bidirectionally communicably connected to the driving control unit 26 through an in-vehicle communication line (e.g., CAN: Controller Area Network). Also, between the driving control unit 26 and the map locator calculation unit 12, similarly, they are bidirectionally communicably connected through the in-vehicle communication line.

[0048] The driving control unit 26 performs driving control of the host vehicle based on the driving environment information acquired and collected by the camera unit 21, the surrounding monitoring unit 22, and the locator unit 11. Note that these various driving environment information includes out-of-vehicle noise information that can affect the vital signs of the driver (described later). The noise information includes, for example, deteriorated forward visibility (night, fog, whiteout, etc.), sudden appearance of pedestrians, etc., sudden stop of the preceding vehicle, and various information about specific vehicles (training vehicles, taxis, etc.).

[0049] The driving control unit 26 is connected to an integrated control unit 30, a steering control unit 31, a brake control unit 32, and an acceleration / deceleration control unit 33.

[0050] The integrated control unit 30 integrates the systems and functions of the entire host vehicle. The integrated control unit 30 is connected to a human machine interface (HMI) 35, an electronic control damper 36, etc.

[0051] The HMI35 includes a display device and a speaker as notification means for informing the driver of various information. The display device is, for example, a touch panel display device. Thus, the display device also functions as an interface for the driver to input various setting information.

[0052] Furthermore, the HMI35 includes switches and sensors related to the driver's operation, such as a mode selector switch, steering angle sensor, steering torque sensor, accelerator pedal position sensor, and brake pedal stroke sensor.

[0053] Furthermore, the HMI35 includes sensors for detecting the driver's vital information, such as a steering wheel touch sensor, a driver monitoring system (DMS), a seating sensor, an infrared sensor, and an in-vehicle communication device. Here, vital information in this embodiment refers to vital information in a broad sense, including, for example, the driver's pulse, blood pressure, respiration, body temperature, and level of consciousness. Such vital information can be used to estimate the driver's state. Each sensor directly or indirectly acquires information related to the driver's vitals. For example, the steering wheel touch sensor detects the driver's pulse and grip strength. Also, for example, the driver monitoring system detects the driver's facial expression and gaze. Information such as the driver's facial expression and gaze can contribute to estimating the driver's level of alertness and excitement. Also, for example, the seating sensor detects the driver's seating posture. Information such as the driver's seating posture can contribute to estimating the driver's level of alertness. Also, the infrared sensor detects the driver's body temperature. The in-vehicle communication device receives (detects) information such as muscle status from wearable devices attached to various parts of the driver's body. In this case, the wearable devices are, for example, attached to each arm and each leg of the driver. Each wearable device measures electromyographic signals, muscle sound signals, and sweat lactate levels in various parts of the driver's body and transmits them to the in-vehicle communication device. These signals are vital information that can be used to estimate the degree of fatigue in each part of the body. Thus, in this embodiment, HMI 35 corresponds to one specific example of the detection means.

[0054] Furthermore, the HMI35 includes sensors for detecting the state of the occupants (including the driver) in the vehicle, such as an in-vehicle surveillance camera, a microphone, and the in-vehicle communication device mentioned above. For example, the in-vehicle surveillance camera detects information related to the occupants' state, such as their behavior and facial expressions. The microphone detects information related to the occupants' state, such as the content of their conversations. The in-vehicle communication device detects information related to the occupants' state, such as the content of their phone calls and emails. This information related to the occupants' state can also be used as noise information to estimate the cause of changes in the driver's vital signs.

[0055] The various pieces of information detected by the HMI 35 are output to the driving control unit 26 via the integrated control unit 30.

[0056] The electronically controlled damper 36 is provided in the suspension system. The controlled damper 36 can change its damping characteristics in real time, for example, based on a control signal from the integrated control unit 30.

[0057] The steering control unit 31 performs, for example, drive control to the electric power steering motor of a steering mechanism (not shown). This drive control is performed, for example, based on control signals from the driving control unit 26 and detection signals from the switches and sensors of the HMI 35 (steering angle sensor, steering torque sensor, etc.). As a result, the steering control unit 31 performs steering control of the steering mechanism.

[0058] In this embodiment, for example, a drive-by-wire steering mechanism is employed. Therefore, the steering control unit 31 can limit the actual steering angle based on a control signal from the driving control unit 26 when a sudden change in the steering angle occurs, for example, due to the driver's steering operation.

[0059] The brake control unit 32 performs, for example, drive control to a brake actuator (not shown). This drive control to the brake actuator is performed, for example, based on a control signal from the driving control unit 26 and detection signals from the switches and sensors of the HMI 35 (such as a brake pedal stroke sensor). As a result, the brake control unit 32 decelerates the vehicle by applying the brakes forcibly.

[0060] In this embodiment, for example, a drive-by-wire type brake actuator is employed. Therefore, the brake control unit 32 can, for example, limit the rapid deceleration of its own vehicle based on a control signal from the driving control unit 26 when a sudden change occurs in the brake stroke due to the driver's brake operation.

[0061] The acceleration / deceleration control unit 33 performs drive control to a power source of a power unit (not shown), for example. The power source may be an engine, a motor, or a combination thereof. Drive control to the power source is performed, for example, based on control signals from the driving control unit 26 and detection signals from the switches and sensors of the HMI 35 (accelerator opening sensor, brake stroke sensor, etc.). As a result, the acceleration / deceleration control unit 33 performs acceleration and deceleration control of the vehicle using the power unit.

[0062] In this embodiment, a drive-by-wire power unit is employed. Therefore, the acceleration / deceleration control unit 33 can, for example, limit the rapid acceleration of its own vehicle based on a control signal from the driving control unit 26 when a sudden change occurs in the accelerator opening due to the driver's accelerator operation.

[0063] The driving control unit 26 sets a target path on the driving route set by the driving route setting calculation unit 12b. Then, based on driving environment information and vehicle position information, the driving control unit 26 can make the vehicle drive along the target path. Such driving control is achieved by controlling the steering control unit 31, brake control unit 32, acceleration / deceleration control unit 33, etc., in a predetermined manner.

[0064] In other words, the driving control unit 26 controls each control unit 31 to 33, etc., to a predetermined degree, thereby performing adaptive cruise control (ACC), active lane keep centering control (ALKC), active lane keep bouncing (ALKB), and sway suppression control. The driving control unit 26 also performs collision avoidance control for targets that are likely to collide with the vehicle, as needed. The driving control unit 26 also performs lane change control, as needed. Furthermore, the driving control unit 26 performs output suppression control of the vehicle in response to sudden driving operations by the driver, as needed. In this output suppression control, for example, if there is a sudden change in steering angle and accelerator opening due to the driver's driving operation, predetermined limits are placed on the actual steering angle and acceleration. As these various driving controls are well known, a detailed explanation is omitted.

[0065] Here, the driving control unit 26 can select between an automatic driving mode and a manual driving mode as the driving control mode.

[0066] The autonomous driving mode in this embodiment refers to, for example, a driving control mode of Level 4 or higher as defined by the SAE (Society of Automotive Engineers). This autonomous driving mode is a mode for performing autonomous driving control that does not require driver intervention. Autonomous driving control can be achieved by appropriately combining the various driving control methods described above.

[0067] In contrast, the manual driving mode in this embodiment is, for example, a driving control mode of level 2 or lower as defined by the SAE. This manual driving mode is a mode that requires driver intervention under certain conditions.

[0068] This manual driving mode includes an "unrestricted manual driving mode" in which no restrictions (driving control) are placed on the vehicle's behavior in response to the driver's driving operations, and a "restricted manual driving mode" in which driver assistance control using the various driving control methods described above intervenes as appropriate during the driver's driving operations. In the restricted manual driving mode, predetermined driver assistance control is intervened. Driver assistance control can be achieved by appropriately combining the various driving control methods described above. As a result, in the restricted manual driving mode, restrictions are appropriately placed on the vehicle's behavior in response to the driver's driving operations by the driver assistance control.

[0069] The driving control unit 26 basically switches between automatic driving mode and manual driving mode based on a signal from the mode switching switch of the HMI 35. Furthermore, if the driver performs a predetermined driving operation (accelerator operation, steering wheel operation, brake operation, etc.) for a set time (for example, 3 seconds) or longer while the automatic driving mode is running, the driving control unit 26 determines that an override has occurred and switches from automatic driving mode to manual driving mode.

[0070] However, the driving control unit 26 appropriately restricts switching from automatic driving mode to manual driving mode based on the driver's vital information obtained from the HMI 35. To determine such restrictions on switching to manual driving mode, the driving control unit 26 estimates the driver's level of alertness based on the driver's vital information. That is, the driving control unit 26 extracts items related to the driver's level of alertness (for example, the driver's facial expression, gaze, body temperature, and pulse rate) from the detected vital information. Then, the driving control unit 26 calculates a driver alertness evaluation value A from each extracted item, for example, by referring to a pre-set map. The higher the value of this alertness evaluation value A, the lower the level of alertness. That is, the higher the value of the alertness evaluation value A, the more it indicates that the driver's condition is unstable and unsuitable for driving.

[0071] The driving control unit 26 determines whether to switch from automatic driving mode to manual driving mode based on the calculated alertness evaluation value A. For example, when the driver attempts to switch to manual driving mode while automatic driving mode is running, the driving control unit 26 compares the current alertness evaluation value A with a preset first threshold Ath1. If the alertness evaluation value A is less than the first threshold Ath1, the driving control unit 26 determines that the driver's state is stable and suitable for manual driving, and permits switching to manual driving mode. On the other hand, if the alertness evaluation value A is greater than or equal to the first threshold Ath1, the driving control unit 26 determines that the driver's state is unstable and unsuitable for manual driving, and prohibits switching to manual driving mode.

[0072] Furthermore, when permission is granted to switch to manual driving mode, the driving control unit 26 evaluates the driver's state before switching to manual driving mode. This evaluation of the driver's state before switching is performed, for example, based on the alertness evaluation value A0 (for example, the maximum value of the alertness evaluation value A) at the set time before switching to manual driving mode. That is, the driving control unit 26 compares the alertness evaluation value A0 at the set time before switching to manual driving mode with a preset second threshold Ath2. Here, the second threshold Ath2 is set to a value greater than the first threshold Ath1.

[0073] Then, when the alertness evaluation value A0 before switching to manual driving mode is less than the second threshold Ath2, the driving control unit 26 determines that the driver's state was in a stable state suitable for manual driving and executes the unrestricted manual driving mode.

[0074] On the other hand, if the alertness evaluation value A0 before switching to manual driving mode is greater than or equal to the second threshold Ath2, the driving control unit 26 determines that the driver's state was unstable and unsuitable for manual driving. In this case, the driving control unit 26 executes a restricted manual driving mode as the mode during the transition from automatic driving mode to unrestricted manual driving mode. In this restricted manual driving mode, intervention by driver assistance control is permitted. Driver assistance control in this restricted manual driving mode includes, for example, inter-vehicle distance control and lane departure prevention control. It is also possible to add driving controls other than inter-vehicle distance control and lane departure prevention control to the driver assistance control in the restricted manual driving mode.

[0075] Furthermore, the driving control unit 26 selects a specific driving control from among several types of driving controls to be added to the manual driving mode, depending on the occupant's state (behavior, etc.) before switching to manual driving mode. This addition of specific driving controls is also performed while the unrestricted manual driving mode is in operation. In other words, even while the unrestricted manual driving mode is in operation, the driver's driving operations are partially restricted by specific driving controls that correspond to the occupant's state.

[0076] Specifically, for example, when a passenger other than the driver is asleep, the driving control unit 26 includes at least one of the following in its specific driving control: inter-vehicle distance control and lane departure prevention control. Here, for example, if inter-vehicle distance control is included in the specific driving control, the driving control unit 26 sets the target inter-vehicle distance for inter-vehicle distance control to be longer than the normal target inter-vehicle distance (e.g., the reference value of the target inter-vehicle distance). Furthermore, the driving control unit 26 suppresses the acceleration generated by the inter-vehicle distance control (e.g., the absolute value of longitudinal acceleration) to be less than a predetermined value. Also, for example, if lane departure prevention control is included in the specific driving control, the driving control unit 26 suppresses the acceleration generated by the lane departure prevention control (e.g., the absolute value of lateral acceleration) to be less than a predetermined value.

[0077] Furthermore, when passengers other than the driver are asleep, the driving control unit 26 includes damper control of the suspension system in certain driving controls. In this case, the driving control unit 26 sets the damping characteristics of the electronically controlled damper 36 to be greater than the normal damping characteristics (for example, the reference value of the damping characteristics).

[0078] Furthermore, when an occupant is performing a predetermined communication action, the driving control unit 26 includes at least one of the following in the specific driving control: inter-vehicle distance control and lane departure prevention control. Here, for example, if inter-vehicle distance control is included in the specific driving control, the driving control unit 26 sets the target inter-vehicle distance for inter-vehicle distance control to be longer than the normal target inter-vehicle distance (e.g., a reference value for the target inter-vehicle distance). Furthermore, the driving control unit 26 suppresses the acceleration generated by the inter-vehicle distance control (e.g., the absolute value of longitudinal acceleration) to be less than a predetermined value. Also, for example, if lane departure prevention control is included in the specific driving control, the driving control unit 26 suppresses the acceleration generated by the lane departure prevention control (e.g., the absolute value of lateral acceleration) to be less than a predetermined value. Here, in this embodiment, the occupant's communication action includes, for example, making phone calls and sending emails using a mobile terminal. Furthermore, the occupant's communication action also includes, for example, conversations inside the vehicle.

[0079] Furthermore, when an occupant is performing a task requiring concentration, the driving control unit 26 includes at least one of the following in its specific driving control: inter-vehicle distance control and lane departure prevention control. Here, for example, if inter-vehicle distance control is included in the specific driving control, the driving control unit 26 sets the target inter-vehicle distance for inter-vehicle distance control to be longer than the normal target inter-vehicle distance (e.g., a reference value for the target inter-vehicle distance). Furthermore, the driving control unit 26 suppresses the acceleration generated by the inter-vehicle distance control (e.g., the absolute value of longitudinal acceleration) to be less than a predetermined value. Also, for example, if lane departure prevention control is included in the specific driving control, the driving control unit 26 suppresses the acceleration generated by the lane departure prevention control (e.g., the absolute value of lateral acceleration) to be less than a predetermined value. Here, in this embodiment, tasks requiring concentration include, for example, playing games using a mobile device, and certain manual tasks.

[0080] Thus, in this embodiment, the driving control unit 26 corresponds to one specific example of the driving control means, the first determination means, and the second determination means.

[0081] Next, the control of switching the driving mode will be explained according to the driving mode switching control routine shown in Figures 2 and 3. This routine is repeatedly executed at set intervals in the driving control unit 26.

[0082] When the routine starts, in step S101, the driving control unit 26 checks whether the current driving mode is automatic driving mode.

[0083] Then, if it is determined in step S101 that the driving mode is not the automatic driving mode (step S101: NO), the driving control unit 26 proceeds to step S109.

[0084] On the other hand, if it is determined in step S101 that the driving mode is automatic driving mode (step S101: YES), the driving control unit 26 proceeds to step S102.

[0085] In step S102, the driving control unit 26 checks whether an off operation for automatic driving has been performed. That is, the driving control unit 26 checks, for example, whether the mode switching switch has been operated by the driver, and whether an override has been determined by the driver's driving operation. If at least one of these is determined, the driving control unit 26 determines that an off operation for automatic driving has been performed.

[0086] Then, if it is determined in step S102 that no off operation has been performed for automatic driving (step S102: NO), the driving control unit 26 proceeds to step S104.

[0087] On the other hand, if it is determined in step S102 that an off operation for automatic driving has been performed (step S102: YES), the driving control unit 26 proceeds to step S103.

[0088] In step S103, the driving control unit 26 checks whether the current alertness evaluation value A is less than a preset first threshold Ath1.

[0089] Then, in step S103, if it is determined that the current alertness evaluation value A is equal to or greater than the first threshold Ath1 (step S103: NO), the driving control unit 26 proceeds to step S104.

[0090] When the process proceeds from step S102 or step S103 to step S104, the driving control unit 26 continues to execute the current automatic driving mode and then exits the routine.

[0091] On the other hand, if in step S103 it is determined that the current level of alertness evaluation value A is less than the first threshold Ath1 (step S103: YES), the driving control unit 26 proceeds to step S105.

[0092] In step S105, the driving control unit 26 checks the status of the occupants. Specifically, the driving control unit 26 checks the status of the driver and passengers based on information from, for example, an in-vehicle surveillance camera, a microphone, and an in-vehicle communication device.

[0093] In the subsequent step S106, the driving control unit 26 checks whether the alertness evaluation value A0 for the set time before the off operation for autonomous driving is less than a preset second threshold Ath2 (where Ath2 > Ath1).

[0094] Then, in step S106, if it is determined that the alertness evaluation value A0 is equal to or greater than the second threshold Ath2 (step S106: NO), the driving control unit 26 proceeds to step S108.

[0095] On the other hand, if in step S106 it is determined that the alertness evaluation value A0 is less than the second threshold Ath2 (step S106: YES), the driving control unit 26 proceeds to step S107.

[0096] In step S107, the driving control unit 26 executes the unrestricted manual driving mode and then proceeds to step S109.

[0097] Furthermore, when proceeding from step S106 to step S108, the travel control unit 26 executes a limited manual driving mode and then proceeds to step S109.

[0098] Furthermore, when the system proceeds from step S101, step S107, or from step S108 to step S109, the driving control unit 26 checks whether the driver has performed an ON operation for automatic driving. That is, the driving control unit 26 checks, for example, whether the driver has operated the mode switching switch.

[0099] Then, if it is determined in step S109 that the ON operation for self-propelled driving has not been performed (step S109: NO), the driving control unit 26 proceeds to step S112.

[0100] On the other hand, if it is determined in step S109 that an ON operation for automatic driving has been performed (step S109: YES), the driving control unit 26 proceeds to step S110.

[0101] In step S110, the driving control unit 26 checks whether the system conditions for executing the automatic driving mode are met.

[0102] Then, if it is determined in step S110 that the system conditions are met (step S110: YES), the driving control unit 26 proceeds to step S111.

[0103] In step S111, the driving control unit 26 exits the routine after executing the automatic driving mode.

[0104] On the other hand, if it is determined in step S110 that the system conditions are not met (step S110: NO), the driving control unit 26 proceeds to step S112.

[0105] When the system proceeds from step S109 or from step S110 to step S112, the travel control unit 26 checks whether a preset time has elapsed since the operating mode was switched to manual operation mode.

[0106] Then, in step S112, if it is determined that the set time has not elapsed since switching to manual driving mode (step S112: NO), the driving control unit 26 proceeds to step S114.

[0107] On the other hand, if in step S112 it is determined that a set time has elapsed since switching to manual driving mode (step S112: YES), the driving control unit 26 proceeds to step S113.

[0108] In step S113, the travel control unit 26 exits the routine after executing the unrestricted manual driving mode.

[0109] Furthermore, when proceeding from step S112 to step S114, the driving control unit 26 checks whether or not the restricted manual driving mode is currently in operation.

[0110] Then, if it is determined in step S114 that the unrestricted manual driving mode is in operation (step S114: NO), the driving control unit 26 proceeds to step S117.

[0111] On the other hand, if it is determined in step S114 that the restricted manual driving mode is in operation (step S114: YES), the driving control unit 26 proceeds to step S115.

[0112] In step S115, the driving control unit 26 checks whether the current alertness evaluation value A is less than a preset third threshold Ath3. Here, the third threshold Ath3 is set to a value smaller than the first threshold Ath1. This third threshold Ath3 is a threshold for determining whether the driver's alertness level has improved sufficiently. In other words, when the alertness evaluation value A is less than the third threshold Ath3, the driving control unit 26 can determine that the driver is in a state that is sufficiently suitable for manual driving.

[0113] Then, in step S115, if it is determined that the alertness evaluation value A is equal to or greater than the third threshold Ath3 (step S113: NO), the driving control unit 26 proceeds to step S119 while maintaining the execution of the restricted manual driving mode.

[0114] On the other hand, if in step S115 it is determined that the alertness evaluation value A is less than the third threshold Ath3 (step S115: YES), the driving control unit 26 proceeds to step S116.

[0115] When the system proceeds from step S115 to step S116, the driving control unit 26 executes the unrestricted manual driving mode and then proceeds to step S119. That is, the driving control unit 26 cancels the intervention of the driving assistance control by switching the driving mode from the restricted manual driving mode to the unrestricted manual driving mode.

[0116] Furthermore, when the system proceeds from step S114 to step S117, the driving control unit 26 checks whether the change in the alertness evaluation value A, ΔA, is greater than a preset threshold ΔAth. Here, the case where the change in the alertness evaluation value A, ΔA, is greater than the threshold ΔAth is when it is anticipated that the driver's state, which was suitable for manual driving, will transition to a state that is unsuitable for manual driving.

[0117] Then, in step S117, if it is determined that the change amount ΔA of the alertness evaluation value A is less than or equal to the threshold ΔAth (step S117: NO), the driving control unit 26 proceeds to step S119 while maintaining the execution of the unrestricted manual driving mode.

[0118] On the other hand, if in step S117 it is determined that the change in the alertness evaluation value A ΔA is greater than or equal to the threshold ΔAth (step S117: YES), the driving control unit 26 executes the restricted manual driving mode and then proceeds to step S119. That is, the driving control unit 26 switches the driving mode from the unrestricted manual driving mode to the restricted manual driving mode.

[0119] When the process proceeds from step S115, step S116, step S117, or from step S118 to step S119, the driving control unit 26 performs additional driving control processing. In the restricted manual driving mode, predetermined driving control is performed by the driver assistance control, so the additional driving control processing is specifically for changing the unrestricted manual driving mode into a partially restricted manual driving mode.

[0120] This additional processing is performed, for example, according to the flowchart of the additional processing subroutine for driving control shown in Figure 4.

[0121] When the subroutine starts, in step S201, the driving control unit 26 refers to the result of step S105 described above and checks whether or not it has detected a sleep state for the occupants (for example, passengers other than the driver).

[0122] Then, if it is determined in step S201 that the sleep state of the occupant has not been detected (step S201: NO), the driving control unit 26 proceeds to step S205.

[0123] On the other hand, if it is determined in step S201 that the occupant is asleep (step S201: YES), the driving control unit 26 proceeds to step S202.

[0124] In step S202, the driving control unit 26 selects, for example, inter-vehicle distance control and lane departure prevention control as driving control (specific driving control) to be added to the manual driving mode. Note that the driving control selected in step S202 may be either inter-vehicle distance control or lane departure prevention control.

[0125] In the subsequent step S203, the driving control unit 26 adjusts the control characteristics of the driving control selected in step S202. For example, if inter-vehicle distance control is selected, the driving control unit 26 sets the target inter-vehicle distance for inter-vehicle distance control to be longer than the normal target inter-vehicle distance (for example, the reference value of the target inter-vehicle distance). Furthermore, the driving control unit 26 adjusts the control characteristics to suppress the acceleration generated by the inter-vehicle distance control (for example, the absolute value of longitudinal acceleration) to be less than a predetermined value. Also, for example, if lane departure prevention control is selected, the driving control unit 26 adjusts the control characteristics to suppress the acceleration generated by the lane departure prevention control (for example, the absolute value of lateral acceleration) to be less than a predetermined value.

[0126] In the following step S204, the driving control unit 26 adjusts the electronically controlled damper 36 of the suspension system. Specifically, the driving control unit 26 sets the damping characteristics of the electronically controlled damper 36 to be greater than the normal damping characteristics (for example, the reference value of the damping characteristics).

[0127] When the system proceeds from step S201 or step S204 to step S205, the driving control unit 26 refers to the result of step S105 described above and checks whether or not it has detected the occupant's communication actions.

[0128] Then, in step S205, if it is determined that the occupant is performing a predetermined communication action (step S205: YES), the driving control unit 26 proceeds to step S207.

[0129] On the other hand, if the driving control unit 26 determines in step S205 that the occupant is not performing a communication action (step S205: NO), the unit proceeds to step S206.

[0130] In step S206, the driving control unit 26 refers to the result of step S105 described above and checks whether or not it has detected a task requiring concentration from the occupant.

[0131] Then, if it is determined in step S206 that no work requiring concentration by the occupant has been detected (step S206: NO), the driving control unit 26 exits the subroutine.

[0132] On the other hand, if step S206 determines that a task requiring concentration by the occupant has been detected (step S206: YES), the driving control unit 26 proceeds to step S207.

[0133] When the system proceeds from step S205 or step S206 to step S207, the driving control unit 26 selects, for example, inter-vehicle distance control and lane departure prevention control as driving control (specific driving control) to be added to the manual driving mode. Note that the driving control selected in step S207 may be either inter-vehicle distance control or lane departure prevention control.

[0134] In the following step S208, the driving control unit 26 adjusts the control characteristics of the driving control selected in step S207 and then exits the subroutine. For example, if inter-vehicle distance control is selected, the driving control unit 26 sets the target inter-vehicle distance for inter-vehicle distance control to be longer than the normal target inter-vehicle distance (for example, the reference value of the target inter-vehicle distance). Furthermore, the driving control unit 26 adjusts the control characteristics to suppress the acceleration generated by the inter-vehicle distance control (for example, the absolute value of longitudinal acceleration) to be less than a predetermined value. Also, for example, if lane departure prevention control is selected, the driving control unit 26 adjusts the control characteristics to suppress the acceleration generated by the lane departure prevention control (for example, the absolute value of lateral acceleration) to be less than a predetermined value.

[0135] According to this embodiment, the driving control unit 26 determines whether to switch from automatic driving mode to manual driving mode based on predetermined conditions. At that time, the driving control unit 26 selects a specific driving control to be added to the manual driving mode from among several types of driving control, depending on the state of the occupant before switching to manual driving mode.

[0136] This allows the driver's intentions to be accurately reflected in the vehicle's behavior while ensuring appropriate driving performance after switching from automatic driving mode to manual driving mode. In other words, depending on the occupant's state before switching to manual driving mode, the driving control unit 26 adds specific driving control to the manual driving mode. This suppresses excessive intervention by driver assistance control and ensures appropriate driving performance while fully reflecting the driver's intentions.

[0137] For example, when an occupant other than the driver is asleep, the driving control unit 26 adds at least one of the following to the manual driving mode: inter-vehicle distance control and lane departure prevention control. The driving control unit 26 then suppresses the acceleration generated by these driving controls to below a predetermined value. This ensures that the vehicle can be driven in manual driving mode without disturbing the occupant's sleep. Furthermore, when an occupant other than the driver is asleep, the driving control unit 26 sets the damping characteristics of the electronically controlled damper 36 of the suspension system to a damping characteristic greater than the normal damping characteristics. This ensures that the vehicle can be driven in manual driving mode without disturbing the occupant's sleep.

[0138] Furthermore, for example, when occupants are communicating, at least one of the following—inter-vehicle distance control and lane departure prevention control—is added to the manual driving mode. This allows the system to switch to manual driving mode while ensuring appropriate driving performance (safety), even if occupant communication suddenly escalates into an argument or other disruptive behavior, causing the driver's psychological state to become unstable. It also ensures appropriate driving performance that does not interfere with conversations between occupants.

[0139] Furthermore, for example, when an occupant is performing a task that requires concentration, the driving control unit 26 adds at least one of the following to the manual driving mode: inter-vehicle distance control and lane departure prevention control. This ensures that, for example, even if the driver's concentration is interrupted after switching to manual driving mode, appropriate driving performance can be ensured. It also ensures appropriate driving performance that does not interfere with the focused work of occupants other than the driver.

[0140] In the above-described embodiment, the locator calculation unit 12, forward driving environment recognition unit 21d, surrounding driving environment recognition unit 22b, driving control unit 26, steering control unit 31, brake control unit 32, and acceleration / deceleration control unit 33, etc., are composed of a well-known microcomputer equipped with a CPU, RAM, ROM, non-volatile memory, etc., and its peripheral devices. The ROM, which is a non-temporary recording medium, stores in advance programs executed by the CPU and fixed data such as data tables. Note that all or part of the functions of the processor may be composed of logic circuits or analog circuits, and the processing of various programs may be realized by electronic circuits such as FPGAs.

[0141] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and changes are possible, all of which fall within the technical scope of the present invention. For example, in the embodiments described above, the driver's level of alertness is used to determine whether or not to switch to manual driving mode, and to select between unrestricted manual driving mode and restricted manual driving mode. Alternatively, the driver's level of excitement or the like could be used instead of the driver's level of alertness.

Claims

1. A vehicle control device capable of switching between an automatic driving mode that does not require driver operation and a manual driving mode that requires driver operation, comprising: detection means for detecting the state of occupants in the vehicle; driving control means for performing multiple types of driving control on the vehicle; first determination means for determining a switch from the automatic driving mode to the manual driving mode; and second determination means for selecting a specific driving control to be added to the manual driving mode from among the multiple types of driving control, according to the state of the occupants before switching to the manual driving mode.

2. The vehicle control device according to claim 1, characterized in that the second determination means includes at least one of inter-vehicle distance control and lane departure prevention control in the specific driving control when a passenger other than the driver is in a sleeping state.

3. The vehicle control device according to claim 2, characterized in that the second determination means suppresses the acceleration generated by the specific driving control to less than a predetermined value.

4. The vehicle control device according to claim 1, characterized in that the second determination means includes damper control of the suspension device in the specific driving control when a passenger other than the driver is in a sleeping state.

5. The vehicle control device according to claim 1, characterized in that the second determination means includes at least one of inter-vehicle distance control and lane departure prevention control in the specific driving control when the occupant is performing a communication action.

6. The vehicle control device according to claim 5, characterized in that the communication operation is a phone call.

7. The vehicle control device according to claim 5, characterized in that the communication operation is a conversation inside the vehicle.

8. The vehicle control device according to claim 5, characterized in that the second determination means suppresses the acceleration generated by the specific driving control to less than a predetermined value.

9. The vehicle control device according to claim 1, characterized in that the second determination means includes at least one of inter-vehicle distance control and lane departure prevention control in the specific driving control when the occupant is performing work that requires concentration.

10. The vehicle control device according to claim 9, characterized in that the second determination means suppresses the acceleration generated by the specific driving control to less than a predetermined value.

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