Driving assistance control device and driving assistance control method

Abstract

Provided is a driving assistance control device capable of safely stopping a vehicle by increasing and correcting braking force when a driver performs a brake operation when an obstacle is not detected during automatic driving. The driving assistance control device comprises: a braking force detection unit 306 that detects operation of a braking device 12 of a vehicle 100 by the driver of the vehicle 100; an operation request determination unit 308 that determines whether to supplement the braking force of the braking device 12 generated in the vehicle 100 when the braking force detection unit 306 has detected operation of the braking device 12; external information detection units 2, 3 for detecting obstacles in the vicinity of the ego vehicle 100; and a braking force increase control unit 30 that controls increases in the braking force of the braking device 12. If the external information detection units 2, 3 do not detect an obstacle and the driver performs an operation to avoid collision with an obstacle, the braking force of the braking device 12 is supplemented.

Description

Driver assistance control device and driver assistance control method

[0001] The present invention relates to a driver assistance control device and a driver assistance control method that increase and correct the braking force applied to a vehicle when, during autonomous driving of a vehicle, the system has not detected any obstacle information within a range where a collision with the vehicle is possible, and the driver performs a braking operation with the intention of avoiding a collision.

[0002] In conventional autonomous driving systems, if information about obstacles within the vehicle's collision zone is lost due to detection failures by sonar or radar, the system's automatic braking will not activate. In this situation, if the driver has detected the obstacle, they will attempt to avoid the collision with emergency braking. However, since vehicle control relies on the system during autonomous driving, delays in braking or insufficient pedal pressure may prevent the system from applying the necessary braking force to stop the vehicle, potentially leading to a collision with the obstacle. Conventionally, brake assist control has been known, which applies a braking force to the brakes that exceeds the amount of braking force corresponding to the driver's pedal depression to stop the vehicle. In brake assist control, when an obstacle or preceding vehicle is present in front of the vehicle, a braking support device has been disclosed that uses the predicted collision time (TTC), calculated by dividing the distance between the vehicle and the obstacle or preceding vehicle by the relative speed of the vehicle with respect to the obstacle or preceding vehicle, to vary the braking assist activation threshold according to the TTC.

[0003] For example, in the brake assist control disclosed in Patent Document 1, the operating threshold of the brake assist control and the braking force applied to the vehicle are differentiated according to the collision risk level set based on the TTC (Time To Collision) and THW (Time-Head Way) for obstacles ahead and preceding vehicles.

[0004] Also, during autonomous driving where the system can control the vehicle to travel without driver operation of the vehicle, when there is an obstacle in the vicinity of the host vehicle, control to automatically perform a braking operation, for example, AEB (Autonomous Emergency Braking), is widely known.

[0005] Japanese Patent Application Laid-Open No. 2019-142265

[0006] Here, devices such as sonars and radars for detecting obstacles and preceding vehicles tend to have difficulty detecting objects with a high transmittance such as fences and objects with a low height.

[0007] In Patent Document 1, if the system detects a forward obstacle or a preceding vehicle, brake assist control can be implemented according to the collision risk level, but brake assist when the obstacle or the preceding vehicle cannot be detected is not considered, so appropriate control operation cannot be performed and there is a possibility of colliding with an obstacle or a preceding vehicle.

[0008] Also, during autonomous driving where the system controls the vehicle, such as represented by automatic parking, when the system detects an obstacle near the host vehicle, a technique of avoiding a collision with the obstacle by activating an automatic brake is widely known. However, when obstacle information near the host vehicle is lost due to detection omission of a sonar or a radar, the automatic brake by the system cannot be activated.

[0009] Even in such cases, if the driver himself / herself can discover the obstacle, he / she will try to avoid the collision by sudden braking. However, during autonomous driving, the vehicle control is relied on the system, and due to a delay in the braking operation or insufficient stepping force, the braking force required for stopping cannot be generated, and there is a possibility of colliding with the obstacle. Therefore, it is desirable to increase and correct the braking force by the driver's braking operation in a situation where a collision with an obstacle is presumed.

[0010] An object of the present invention is to provide a driving support control device and a driving support control method that can increase and correct the braking force when a driver performs a braking operation intended to avoid a collision in a situation where the system cannot detect an obstacle during autonomous driving and can safely stop the vehicle.

[0011] To achieve the above objective, the present invention is configured as follows.

[0012] In a driver assistance control device that performs automatic driving by assisting at least vehicle speed control and position control among the operation control of a vehicle, the device includes: a braking force detection unit that detects when the driver of the vehicle has activated the vehicle's braking system; an operation request determination unit that determines whether or not to assist the braking force of the braking system generated in the vehicle when the braking force detection unit detects the activation of the braking system; an external information detection unit that detects obstacles in the vicinity of the vehicle; and a braking force increase control unit that controls the increase of the braking force of the braking system. The operation request determination unit determines whether or not an operation to avoid collision with the obstacle has been performed based on the detection result of the braking force detection unit's detection of the activation of the braking system, and when the external information detection unit has not detected the obstacle, and the driver of the vehicle has activated the vehicle's braking system and performed an operation to avoid collision with the obstacle, the device causes the braking force increase control unit to perform assistance of the braking force of the braking system.

[0013] Furthermore, in a driver assistance control method that performs autonomous driving while supporting vehicle speed control and position control among the vehicle's operation control, during autonomous driving, it is determined whether or not an obstacle has been detected near the vehicle, and if no obstacle has been detected near the vehicle, if it is detected that the driver has activated the vehicle's braking system, it is determined whether or not there is a possibility of collision between the vehicle and the obstacle, and if there is a possibility of collision between the vehicle and the obstacle, the braking system is made to provide assistance for the braking force of the vehicle.

[0014] The present invention provides a driver assistance control device and a driver assistance control method that can increase and correct the braking force when the driver performs a braking operation with the intention of avoiding a collision in a situation where the system has not detected an obstacle during autonomous driving, thereby enabling safe stopping.

[0015] By assisting the driver's braking operation during autonomous driving, it is possible to compensate for delays or insufficient braking force caused by relying on autonomous driving, thereby reducing the possibility of collision with obstacles.

[0016] By determining whether or not correction is necessary, not only based on whether or not the brakes were applied, but also by combining this with the likelihood of collision with obstacles inferred from surrounding information, it is possible to activate the control system under appropriate circumstances, thereby improving safety and convenience.

[0017] This is a schematic block diagram showing a vehicle to which the driver assistance control device according to the present invention is applied. This is a schematic block diagram showing an example of the internal configuration of an automatic driving ECU mounted in a vehicle according to the present invention. This is a schematic block diagram showing an example of the internal configuration of a braking force increase control unit according to the present invention. This is a diagram showing a series of processes performed by the braking force increase control according to Embodiment 1 of the present invention in flowchart form. This is a diagram showing an overview of the collision possibility estimation process, which is one of the processes performed by the braking force increase control according to the present invention, in flowchart form. This is a diagram showing a series of processes for inferring the driver's intention to avoid a collision from the brake operation of the brake operation determination unit performed by the braking force increase control according to the present invention, in flowchart form. This is a diagram showing the effect when the braking force applied to the vehicle is increased by the braking force increase control according to the present invention. This is a diagram showing a series of processes for inferring the driver's intention to avoid a collision from the steering operation of the steering operation determination unit performed by the braking force increase control according to Embodiment 2 of the present invention, in flowchart form. This is a diagram showing a series of processes for inferring the possibility of a collision from the sonar detection state of the sonar obstacle detection determination unit performed by the braking force increase control according to Embodiment 3 of the present invention, in flowchart form. This diagram shows a series of processes in flowchart form for estimating the difficulty level of obstacle detection based on route information and surrounding information, in the process of the obstacle detection difficulty determination unit implemented by the braking force increase control according to Embodiment 4 of the present invention. This diagram shows a series of processes in flowchart form for estimating the possibility of driver visibility deterioration based on the surrounding environment and information from various sensors, in the process of the visibility deterioration determination unit implemented by the braking force increase control according to Embodiment 5 of the present invention. This diagram shows a series of processes in flowchart form for estimating the possibility of an object being present around the vehicle from camera images, in the process of the camera recognition determination unit implemented by the braking force increase control according to Embodiment 6 of the present invention. This diagram shows a series of processes in flowchart form for estimating the possibility of collision with obstacles on the planned route, by creating a map that estimates the risk of collision with obstacles from the driving history and surrounding information such as map information, in the process of the route driving history determination unit implemented by the braking force increase control according to Embodiment 7 of the present invention.

[0018] Embodiments of the present invention will be described below with reference to the accompanying drawings.

[0019] (Example 1) Figure 1 is a schematic block diagram showing a vehicle to which the driver assistance control device according to the present invention is applied. In Figure 1, only the components related to the present invention are extracted and shown from the configuration of the vehicle 100.

[0020] The driver assistance control system is mounted on the vehicle 100 and mainly includes a front-mounted camera 2F mounted on the front of the vehicle, a right-mounted camera 2R mounted on the right side of the vehicle, a rear-mounted camera 2B mounted on the rear of the vehicle, a left-mounted camera 2L mounted on the left side of the vehicle, sonar 3, electric power steering system 6, a right front wheel speed sensor 8FR that detects the wheel speed of the right front wheel 7FR, a right rear wheel speed sensor 8RR that detects the wheel speed of the right rear wheel 7RR, a left rear wheel speed sensor 8RL that detects the wheel speed of the left rear wheel 7RL, a left front wheel speed sensor 8FL that detects the wheel speed of the left front wheel 7FL, an onboard display device 9, an automatic driving ECU (Electronic Control Unit) 10, a vehicle control ECU 11, a brake pedal 12, a rain sensor 13, a wiper switch 14, headlights 15, etc.

[0021] The front camera 2F, right camera 2R, rear camera 2B, and left camera 2L are equipped with lenses and image sensors and are appropriately positioned to capture images of the surrounding environment of the vehicle 100. The images captured by each camera 2F, 2R, 2B, and 2L are transmitted to the automatic driving ECU 10 for image processing. Hereafter, unless otherwise specified, cameras 2F, 2R, 2B, and 2L will be referred to as camera 2. Camera 2 may be a monocular camera or a stereo camera. Camera 2 can also be defined as an imaging unit.

[0022] Multiple sonar units 3 are installed on the front, rear, and sides of the vehicle 100. Each sonar unit 3 transmits ultrasonic waves and receives reflected waves from surrounding obstacles to measure the distance to obstacles around the vehicle 100. The measurement results are transmitted to the autonomous driving ECU 10. The autonomous driving ECU 10 stores the obstacle information around the vehicle 100, which is the measurement result transmitted from each sonar unit 3.

[0023] The camera 2 and sonar 3 described above constitute an external information acquisition unit for acquiring external information about the area around the vehicle 100. Note that external information about the area around the vehicle 100 may also be acquired using sensing means other than the camera 2 and sonar 3.

[0024] The vehicle 100 has a right front wheel 7FR, a right rear wheel 7RR, a left rear wheel 7RL, and a left front wheel 7FL positioned on the front, rear, left, and right sides of its body. Each of these wheels 7FR, 7RR, 7RL, and 7FL is equipped with a right front wheel speed sensor 8FR, a right rear wheel speed sensor 8RR, a left rear wheel speed sensor 8RL, and a left front wheel speed sensor 8FL. Each wheel speed sensor 8FR, 8RR, 8RL, and 8FL detects the speed of its respective wheel and transmits this speed to the automatic driving ECU 10. The automatic driving ECU 10 calculates the speed of the vehicle 100 based on the above information on the speeds of each wheel. In the following, unless otherwise specified, the right front wheel 7FR, right rear wheel 7RR, left rear wheel 7RL, and left front wheel 7FL will be referred to as wheel 7, and the right front wheel speed sensor 8FR, right rear wheel speed sensor 8RR, left rear wheel speed sensor 8RL, and left front wheel speed sensor 8FL will be referred to as wheel speed sensors 8.

[0025] The electric power steering system 6 changes the direction of the wheels 7 according to the amount of movement (steering angle) of the steering wheel 18 located in the driver's cab of the vehicle 100.

[0026] The electric power steering system 6 includes, for example, a steering angle sensor that detects the steering angle of the steering wheel 18, a motor that assists the steering torque which is the torque that changes the direction of each wheel 7, and an electric power steering ECU (none of which are shown) that controls the steering torque, and controls the steering torque to change the direction of the wheels 7 in order to assist the driver's operation of the steering wheel 18. The steering angle detected by the steering angle sensor of the electric power steering system 6 is transmitted to the automatic driving ECU 10. The automatic driving ECU 10 calculates the direction of travel of the vehicle 100 based on the above steering angle information.

[0027] The in-vehicle display device 9 is installed in the driver's cab of the vehicle 100 and provides various information to the driver. The information provided to the driver includes, for example, images captured by the camera 2 and processed by the autonomous driving ECU 10. Furthermore, as described later, the in-vehicle display device 9 displays on the screen whether the vehicle is in autonomous driving mode by means of an icon display or the like. The in-vehicle display device 9 may be configured as, for example, a touch panel integrating a display and an input device, as part of a car navigation system, or as a head-up display. The in-vehicle display device 9 may also be equipped with information input devices such as a keyboard, a voice instruction device, or switches. The screen of the in-vehicle display device 9 is equipped with a pressure-sensitive or capacitive touch panel, enabling various input operations, and the driver can transmit the input content to the autonomous driving ECU 10 by performing input operations on the touch panel.

[0028] The autonomous driving ECU 10 has a camera 2 and a sonar 3 that constitute an obstacle detection unit. Based on environmental information data received from the camera 2 and sonar 3, it detects obstacles around the vehicle 100. The detection accuracy of surrounding objects is affected when an obstacle is recognized by the camera 2. The further the parking space line is from the vehicle 100, the more likely it is that the recognized position will deviate from the actual position, and the greater the relative distance from the camera 2, the greater the deviation tends to be. Similarly, when an obstacle is recognized by the sonar 3, the greater the relative distance from the sonar 3 to the obstacle, the greater the deviation tends to be. Furthermore, the detection accuracy tends to be affected by factors such as the material, transmittance, and height of the object.

[0029] The initiation of autonomous driving may be carried out in a well-known and publicly recognized manner, and may include, for example, following a preceding vehicle or a driving lane detected by a surrounding situation recognition system, or automatic parking aimed at moving the vehicle into a parking space.

[0030] The autonomous driving ECU 10 calculates a driving path from the vehicle 100's stopping position to the selected location based on the drivable area and obstacle information detected by the sonar 3, and transmits the calculated driving path to the vehicle control ECU 11.

[0031] The vehicle control ECU 11 assists the driving of its own vehicle 100 based on the driving path transmitted from the automatic driving ECU 10 by assisting one or all of the driver's steering wheel 18 operation, accelerator operation, brake operation, etc.

[0032] For example, the vehicle control ECU 11 outputs target steering angle information to the electric power steering device 6 and outputs the requested driving force to the driving force control ECU (not shown) which controls the driving force of the vehicle 100. Then, it outputs the requested braking force to the braking force control ECU (not shown) which controls the braking force of the vehicle 100 by the braking device such as the brake pedal 12. This controls the speed of the vehicle 100 and outputs a request for drive range, reverse range, or parking range to the shift-by-wire control device (not shown) which controls the shift range of the automatic transmission, thereby controlling the shift range of the vehicle 100. By controlling the vehicle 100 with the vehicle control ECU 11, the driver can receive appropriate automated driving.

[0033] At the brake pedal 12, a stroke sensor 12s detects the stroke of the brake pedal 12 of the vehicle 100, detecting information such as the amount of brake depressure and the speed of depressure from the amount of operation of the driver's brake pedal 12, and transmits this information to the automatic driving ECU 10. The vehicle 100 generates a braking force corresponding to the detected amount of brake operation and applies braking to the wheels 7. The stroke sensor 12s can not only detect the stroke of the brake pedal 12, but also detect the brake pressure applied by the brake pedal 12.

[0034] The rain sensor 13 detects rainfall on the windshield of the vehicle 100 and transmits this information to the autonomous driving ECU 10. For example, the rain sensor 13 may use an electrical resistance method to detect moisture adhering to the windshield, or it may use infrared reflection to detect the wetness of the windshield. Any method is acceptable and may use known technology.

[0035] The wiper switch 14 is a detector that detects operation instructions for the wipers installed on the front windshield of the vehicle 100. The wiper switch 14 is installed, for example, on the steering column. Wiper operation instructions may include, for example, intermittent operation instructions, low-speed continuous operation instructions, high-speed continuous operation instructions, and operation instructions that automatically determine whether or not to operate the wipers based on the rain detection status of the rain sensor 13. The wiper switch 14 transmits the detected wiper operation instruction information to the automatic driving ECU 10.

[0036] The headlight 15 is a lighting device installed in front of the vehicle 100. The switch operation that gives the operation instructions for the headlight 15 may include, for example, operation instructions such as turn off, low beam, high beam, and automatic on, and the operation state of the switch is transmitted to the automatic driving ECU 10 as the actual operating state of the headlight 15.

[0037] The external information sensor device 19 comprises a GNSS (Global Navigation Satellite System) receiving unit and a map storage unit. Furthermore, the external information sensor device 19 includes a display device, speaker, and operation switches within the in-vehicle display device 9, allowing the driver or other user to utilize the external information sensor device 19.

[0038] The GNSS receiver unit determines the position of the vehicle 100 based on signals received from GNSS satellites. The external information sensor device 19 determines the route from the position of the vehicle 100 determined by the GNSS receiver unit to the destination input by the driver or the like, by referring to map information stored in the map storage unit, which will be described in detail later. This function may be configured as a function independent of the route generation unit 23 (shown in Figure 2) inside the autonomous driving ECU 10, and may be configured as a function used only when autonomous driving is not in progress. The route information generated here is used to guide the driver or the like via the display device and speaker in the in-vehicle display device 9 described above.

[0039] The map storage unit stores highly accurate map information MPU (Map Position Unit). Map information includes, for example, road type, number of road lanes, location of emergency parking areas, lane width, road gradient, road location, curvature of lane curves, location of lane merging and diverging points, information on road signs, intersection location, presence or absence of traffic lights, location of stop lines, traffic congestion information, and information on other vehicles.

[0040] Figure 2 is a schematic block diagram showing an example of the internal configuration of the autonomous driving ECU 10 shown in Figure 1. In Figure 2, the autonomous driving ECU 10 includes a vehicle position estimation unit 21, a collision prediction unit 22, a path generation unit 23, and a steering control unit 24.

[0041] The vehicle position estimation unit 21 calculates the amount of movement, distance traveled, and vehicle coordinates of the vehicle 100 based on the vehicle speed value detected by the wheel speed sensor 8, vehicle information acquired from the external information sensor device 19, and surrounding information, and transmits these to the braking force increase control unit 30. Similarly, the vehicle position estimation unit 21 transmits dedreco information (information such as past driving routes) to the route generation unit 23 and transmits the amount of movement and distance traveled to the steering control unit 24.

[0042] The collision prediction unit 22 extracts information about obstacles within a range where collision is possible with the vehicle 100, based on obstacle information detected by surrounding situation recognition systems such as the camera 2 and sonar 3. It calculates whether nearby obstacles have been detected and the distance between the obstacles and the vehicle 100. The results are then transmitted to the braking force increase control unit 30. For example, if the sonar 3 detects an object that appears to be an obstacle within a certain range of the vehicle 100, or if the onboard camera 2 detects a brightness difference of a certain value or more in the image it recognizes, it may be determined that an obstacle has been detected, assuming that there is an object on the road. Here, the range where collision is possible may be set to a range that has some margin over the range in which the vehicle 100 travels when the vehicle 100 continues normal automatic driving control, or it may be set to a range with an even larger margin considering the possibility of a moving object approaching the vehicle 100.

[0043] In the route generation unit 23, based on the surrounding information detected by the camera 2, the obstacle information detected by the sonar 3, the position coordinates of the host vehicle 100 acquired by the external information sensor device 19, and the map information, information on the driving route along which the host vehicle 100 travels to the target position is created and transmitted to the braking force increase control unit 30. The method of route generation may be implemented using an arbitrary and well-known technique, and the route information generated here is notified to the driver and the like by a display device, a speaker, or the like in the in-vehicle display device 9.

[0044] The steering control unit 24 detects the steering control amount of the driver of the host vehicle 100, and based on the movement amount and the travel distance calculated by the host vehicle position estimation unit 21 and the route information generated by the route generation unit 23, calculates a steering angle instruction value necessary for the host vehicle 100 to travel along the planned route and transmits it to the braking force increase control unit 30.

[0045] The braking force increase control unit 30, which is a driving support control device according to the present invention, is classified as a control unit that creates instructions necessary for the drive control of the host vehicle 100 among the automatic parking ECUs 10. It receives information from the above-described control units, calculates a target braking force necessary for the braking control of the host vehicle 100, and transmits it to the drive instruction creation unit 31. When an emergency braking operation by the driver using the brake is performed during the automatic driving of the host vehicle 100 and no obstacle is detected by the surrounding situation recognition system such as the camera 2 or the sonar 3, and it is determined that the host vehicle 100 is in a situation where there is a high possibility of colliding with an obstacle, the braking force increase control unit 30 increases and corrects the target braking force in order to generate a braking force greater than the braking force generated in the host vehicle 100 by the driver's brake operation.

[0046] In the drive instruction creation unit 31, mediation of the braking force is performed in accordance with the target braking force calculated by the braking force increase control unit 30, the vehicle speed detected by the wheel speed sensor 8, and the driving state and surrounding environment of the host vehicle 100, and an appropriate drive instruction for driving or stopping the host vehicle 100 is determined and transmitted to the vehicle control ECU 11.

[0047] FIG. 3 is a block diagram schematically showing an example of the internal configuration of the braking force increase control unit 30 shown in FIG. 2.

[0048] The braking force increase control unit 30 includes a control operation determination unit 300 that determines whether control operation is present or not. In the control operation determination unit 300, it is determined whether there has been a braking operation intended for collision avoidance in a state where, despite a high possibility of collision with an obstacle, the collision prediction unit 22 has not detected an obstacle within a range where there is a possibility of the obstacle colliding with the host vehicle 100. Specifically, the control units of a visibility deterioration determination unit 301, an obstacle detection difficulty determination 302, a route driving history determination unit 303, a camera recognition determination unit 304, a sonar obstacle detection determination unit 305, a braking operation determination unit (braking force detection unit) 306, and a steering operation determination unit (braking force detection unit) 307, which will be described in detail later, estimate whether the host vehicle 100 is in a situation where there is a high possibility of colliding with an obstacle.

[0049] When it is determined that the host vehicle 100 has a high possibility of colliding with an obstacle, a control operation request is set, and it is determined from the determination result of the collision prediction unit 22 whether the peripheral situation recognition system has detected obstacle information near the host vehicle 100. Then, when the braking operation determination unit 306 detects a driver's braking operation, it determines whether there is an intention to avoid collision with the obstacle from the braking operation amount.

[0050] The braking operation determination unit 306, which is a braking force detection unit, detects a change amount of the depression amount of the brake pedal 12 from a stroke sensor 12s that detects the stroke of the brake pedal 12, and when the depression amount is equal to or greater than a predetermined value and the change amount of the depression amount is within a predetermined range, it notifies the operation request determination unit 308 that an emergency braking operation by the brake pedal 12 has been detected. However, the braking operation determination unit 306 may be configured to detect the depression speed of the brake pedal 12 from the stroke sensor 12s and detect the change amount of the depression amount based on the detected depression speed.

[0051] When the operation request determination unit 308 detects the operation of the brake pedal (braking device) 12, it mediates an operation request to determine whether to assist the braking force generated in the host vehicle 100, and creates a control operation request for operating the braking force increase control 30 using the detection state of the obstacle and the presence or absence of an intention to avoid collision with the obstacle.

[0052] When the target braking force calculation unit 311 receives a control operation request from the control operation determination unit 300, it sets a value greater than the braking force generated by the driver brake (preferably the maximum value stipulated by law) as the target driving force and transmits it to the brake / drive instruction creation unit 31. On the other hand, if there is no control operation request from the control operation determination unit 300, it sets a value corresponding to the amount of driver brake operation as the target driving force and transmits it to the brake / drive instruction creation unit 31.

[0053] The control details of the braking force increase control 30 according to Embodiment 1 of the present invention will be explained using the flowchart in Figure 4.

[0054] In Figure 4, in step S401, the vehicle 100 receives a signal from the autonomous driving ECU 10 that allows it to determine whether autonomous driving is in progress, and determines whether or not autonomous driving is in progress. Here, autonomous driving refers to a state in which the autonomous driving ECU 10 is in charge of any or all of the vehicle control, such as steering wheel operation, accelerator operation, or brake operation, on behalf of the driver. As a means of determining the state of autonomous driving, for example, it may be determined by receiving a CAN signal indicating that the autonomous driving system is in operation, or it may be synchronized with the control state notified to the driver by the in-vehicle display device 9.

[0055] If it is determined in step S401 that the vehicle is in autonomous driving mode, the process proceeds to step S402.

[0056] In step S402, external information of the vehicle 100 is acquired from the surrounding situation recognition system, such as the camera 2 and sonar 3, and from various sensors attached to the vehicle 100, such as the stroke sensor 12s of the brake pedal 12. This external information includes the calculation results of the vehicle position estimation unit 21, collision prediction unit 22, path generation unit 23, and steering control unit 24 shown in Figure 2.

[0057] In step S403, based on the surrounding environment information acquired in step S402 and the control status of the vehicle 100, the visibility deterioration determination unit 301, obstacle detection difficulty determination unit 302, route driving history determination unit 303, camera recognition determination unit 304, sonar obstacle detection determination unit 305, brake operation determination unit 306, and steering operation determination unit 307 in Figure 3 are processed to confirm whether the vehicle 100 is in a situation where it is presumed to have a high probability of colliding with an obstacle.

[0058] In step S404, based on information from the surrounding situation recognition system, such as the camera 2 and sonar 3, the collision prediction unit 22 shown in Figure 2 checks whether or not it has detected any obstacles that could potentially collide with the vehicle 100 in the vicinity. If no obstacles are detected, the process proceeds to step S405. If obstacles are detected, the control process ends. Alternatively, if the system detects an obstacle that could potentially collide with the vehicle 100, braking control to avoid a collision with the obstacle may be performed outside of the control process using a known automatic braking system, such as AEB.

[0059] In step S405, the brake operation determination unit 306 in Figure 3 determines whether the driver performed a braking operation intended to avoid a collision based on information such as the amount of brake depression and speed from the stroke sensor 12s of the brake pedal 12. If a braking operation intended to avoid a collision is detected, the system proceeds to step S406. If a braking operation intended to avoid a collision is not detected, the system proceeds to step S408 to calculate the target braking force.

[0060] In step S406, if in step S403 it is estimated that there is a high probability that the vehicle 100 will collide with an obstacle and the operation of the braking force increase control 30 is required, the process proceeds to step S407. If it is determined that the probability of collision is low and the operation of the braking force increase control 30 is unnecessary, the process proceeds to step S408 to calculate the target braking force.

[0061] By performing the determinations in steps S404, S405, and S406, the system determines that even though there is actually an obstacle that could potentially collide with the vehicle 100, the collision prediction unit 22, in processing, has determined that the presence of the obstacle can be inferred due to some other factor, or that the vehicle 100 is in a situation or control state where there is a high probability of colliding with the obstacle, the system requests the activation of the braking force increase control 30. Conversely, if the presence of a nearby obstacle is clearly detected, or if the obstacle has not been detected but the system determines that there is a low probability of the vehicle colliding with the obstacle, the system does not request the activation of the braking force increase control 30.

[0062] In step S407, the operation request determination unit 308 shown in Figure 3 makes an operation request for braking force increase control, and in step S408, the target braking force calculation unit 311 shown in Figure 3 mediates the target braking force that the automatic driving ECU 10 transmits to the vehicle control ECU 11.

[0063] In step S408, if the aforementioned control operation request is made, a target braking force is set that is greater than the braking force generated on the vehicle 100 by the driver brake, and is large enough to stop the vehicle 100 without colliding with an obstacle, even if an obstacle is present near the vehicle 100. The target braking force set here may be a variable value depending on the collision probability determined in step S403, and the amount of braking force increase correction may be increased in situations where the possibility or risk of collision is presumed to be higher. The amount of braking force increase may also be variable according to the remaining distance to the stopping position, such as the target position or turning point. Specifically, if the remaining distance to the target position or turning point is small, vehicle control toward stopping should already be being performed, and generating a large braking force will not cause discomfort to the driver, so the generated braking force may be increased.

[0064] If there is no control operation request but brake operation by the driver is detected, the braking force corresponding to the amount of brake pedal depression is set as the target braking force. If brake operation by the driver is not detected, the value calculated by the target braking force calculation unit 311 according to the current driving conditions such as vehicle speed is set as the target braking amount. The target braking force set by the above process is transmitted to the brake drive instruction creation unit 31.

[0065] Figure 5 is a diagram showing an overview of the collision possibility estimation process in step S403 in Figure 4. The visibility deterioration determination unit 301, obstacle detection difficulty determination unit 302, route driving history determination unit 303, camera recognition determination unit 304, sonar obstacle detection determination unit 305, brake operation determination unit 306, and steering operation determination unit 307 shown in Figure 3 perform the processing in steps S501 to S507 and set an operation request for increased braking force control to estimate whether or not the vehicle 100 is likely to collide with an obstacle.

[0066] In step S508, the judgment results from steps S501 to S507 are merged. If any action request is set, it is presumed that an obstacle exists due to some factor, or that if an obstacle exists, there is a high probability that the vehicle will collide with the obstacle. Therefore, it is determined that there is a possibility of collision with an obstacle. If all judgments are not met and no action request is set, it is determined that there is no possibility of collision with an obstacle because the risk of collision with an obstacle is low.

[0067] In this case, to determine that a collision is possible, at least one of the following conditions must be met and a control activation request must be set. There may be multiple factors that trigger the setting of the control activation request.

[0068] The determination of whether or not there is a possibility of collision with an obstacle, as determined in step S508, is referenced in the determination in step S406 of Figure 4. In addition, in step S508, the collision risk set for each successful determination (factor requiring control operation) may be checked, and an index may be created to determine the magnitude of the braking force to be generated.

[0069] The control details of the braking force increase control unit 30 in Embodiment 1 of the present invention will be explained using the flowchart in Figure 6. Figure 6 shows an overview of the brake operation determination unit 306, and, according to the flowchart in Figure 4, when the vehicle 100 is in automatic driving mode, it repeatedly sets collision avoidance and control operation requests, which are information for switching whether or not the braking force increase control unit 30 is operating.

[0070] In step S601, the amount of brake pedal depression, the speed of depression, and the braking force generated therefrom are obtained from the stroke sensor 12s of the brake pedal 12.

[0071] In step S602, the change in brake pedal pressure is calculated from the difference between the brake pedal pressure obtained in step S601 and the previously obtained brake pedal pressure. Alternatively, the change in brake pedal pressure may be calculated based on the speed at which the brake pedal is pressed.

[0072] In step S603, it is determined whether the braking force applied by the brake pedal is equal to or greater than the threshold Th1. Here, the threshold Th1 is set to a value greater than or equal to the magnitude corresponding to the brake pedal pressure applied by a typical driver when adjusting the speed of their vehicle 100 while driving or when performing a gradual deceleration (preferably the maximum value stipulated by law), thereby preventing a decrease in user experience due to malfunctions in the control system during brake operations, such as when adjusting the distance to the vehicle in front while driving the vehicle 100.

[0073] If the braking force applied by the brake pedal is greater than or equal to threshold Th1, it is determined that relatively strong braking was applied to avoid a collision with an obstacle, and the process proceeds to step S604 for further determination. In step S604, if the braking force applied by the brake pedal is less than a predetermined threshold Th2, it is determined that the braking was intended to adjust the driving speed or distance between vehicles, and not to avoid a collision, and the process proceeds to steps S612 and S613.

[0074] In step S604, it is determined whether the change in brake depression is greater than or equal to threshold Th2. If it is greater than or equal to threshold Th2, the process proceeds to steps S605 and S606, and the operation of the braking force increase control unit 30 is requested. If the change in brake depression is less than threshold Th2, the process proceeds to step S607 for further determination. Here, threshold Th2 is set to a value equivalent to the magnitude expected to occur when a typical driver suddenly and forcefully presses the brakes in an emergency, thereby detecting a sudden change in brake depression amount and pressing speed. In such a situation, the driver is performing a sudden brake application with the intention of avoiding a collision with an obstacle, and this is considered one of the control activation factors.

[0075] In steps S605 and S606, in order to increase and correct the braking force applied to the vehicle 100 according to the present invention, the control operation request due to the detection of collision avoidance intent and brake operation delay is set to ON.

[0076] In step S607, it is determined whether the change in brake pressure is greater than or equal to threshold Th3. If it is greater than or equal to threshold Th3, the process proceeds to step S608, where it is determined that there is an intention to avoid a collision. If the change in brake pressure is less than threshold Th3, it is determined that there was a relatively strong brake application, but that there is no intention to avoid a collision, such as when the brakes are applied while the vehicle 100 is being decelerated in accordance with the deceleration of the vehicle in front. The process then proceeds to steps S612 and S613. Here, threshold Th3 is smaller than threshold Th2, but is set to a value equivalent to the magnitude that a typical driver would assume to occur when braking with the intention of stopping the vehicle 100 while traveling at a certain speed or higher, thereby detecting the driver's intention to stop.

[0077] Therefore, when the change in brake pressure is within the range of threshold Th3 < change in brake pressure < threshold Th2, it is determined that although sufficient braking action to avoid a collision with an obstacle has not been performed, the minimum amount of braking action necessary to stop the moving vehicle 100 has been performed, and thus it is determined that there was an intention to avoid a collision.

[0078] In step S609, the braking force detection unit 306 determines whether it was able to detect that brake pressure was applied by the brake pedal sensor 12s immediately before the determination was made, or whether it was able to detect the stroke of the brake pedal 12. If either was detected, the process proceeds to step S611. If pressure or stroke was not detected immediately before the determination, it is assumed that the driver's foot was not on the brake pedal sensor 12s until the brake operation was performed, but rather on the footrest or accelerator pedal. In such cases, there is a high possibility that a delay in brake operation will occur due to the driver changing their foot position. In particular, this control assumes autonomous driving, and during autonomous driving, it is highly likely that the driver's foot is not on the brake pedal sensor due to complete reliance on the system, so the process proceeds to step S610.

[0079] In step S610, the control operation request to the braking force increase control unit 30 is set to ON in order to compensate for the delay in brake operation by increasing the braking force.

[0080] On the other hand, in step S611, the control operation request due to brake delay is set to OFF.

[0081] In steps S612 and S613, in order to prevent the braking force increase according to the present invention from being activated, the control operation request due to the absence of collision avoidance intent and detection of brake operation delay is set to OFF.

[0082] Furthermore, if the amount of change in the amount of depression of the brake pedal 12 is greater than a predetermined range in step S609, the process proceeds to step S610, and a braking action request is set to ON for the braking force increase control unit 30 (a request for braking force operation is sent to the braking force increase control unit 30).

[0083] Figure 7 is an image diagram showing the effect of increasing the braking force applied to the vehicle 100 by the braking force increase control unit 30 according to the present invention, when control operation is required in Figure 6 and the braking force increase control unit 30 is activated. The vertical axis in Figure 7 represents the braking force generated by the brake pedal depression detected by the stroke sensor 12s of the brake pedal 12, and the horizontal axis represents the elapsed time. In each braking case shown as 7a, 7b, and 7c in Figure 7, the remaining distance to the obstacle at the starting point is uniformly 5m, and the vehicle speed of the vehicle 100 is the same value in all cases.

[0084] The line 7a in Figure 7 represents a model case where an obstacle exists during automatic parking, but the system fails to detect it. The driver senses danger and begins braking when the distance to the obstacle reaches 5m. Ts1 is defined as the reference time (collision limit) at which the vehicle stops just before the obstacle (distance to the obstacle is 0cm) through appropriate braking. The integral value of the braking force up to the collision limit on line 7a represents the total braking force required for the vehicle 100 to stop just before the obstacle.

[0085] In the braking cases shown by lines 7b and 7c in Figure 7, if the integral value of the braking force up to Ts1 is smaller than that of line 7a, it can be assumed that the necessary braking force cannot be generated and the vehicle will collide with an obstacle. If the integral value is larger than that of line 7a, it can be assumed that the necessary braking force can be generated and the vehicle will stop without colliding with an obstacle.

[0086] In the case shown by line 7b in the diagram, the braking start timing is later than in the braking operation shown by line 7a. In other words, braking operations similar to those in case 7a are performed when the distance to the obstacle is less than 5m, so the vehicle 100 stops later than Ts2, and as a result, it fails to exert the necessary braking force and collides with the obstacle.

[0087] Here, by applying the braking force increase control 30 according to the present invention, the braking force is increased and corrected when the operating conditions of the control are met in response to the braking operation shown in Figure 7b, with the aim of avoiding collision with an obstacle. In the section p of line 7b in the figure, the determinations in steps S603 and S604 in Figure 6 are met, so it can be determined that a braking operation equivalent to sudden braking by the driver has been detected, and since the operating conditions of the control are met, the braking force is increased and corrected.

[0088] As an example of correction, by increasing the braking force as shown by the braking operation indicated by line 7c in the figure, the time Ts3 required to generate the braking force necessary to stop is shortened, thereby avoiding collision with an obstacle. Furthermore, the amount of increase in braking force may be a variable value depending on the control state of the vehicle 100 and the collision risk. For example, a map that determines the amount of increase in braking force according to the vehicle speed may be used. In this map, the amount of increase in braking force is set to be larger as the vehicle speed increases, and smaller as the vehicle speed decreases. In addition, in this embodiment 1, the amount of increase in braking force may be changed according to the amount of change in brake pedal pressure. For example, if the amount of change in brake pedal pressure is large, the risk of collision with an obstacle is high, and it can be assumed that a sudden and strong braking operation has been performed, so the amount of increase in braking force may be set to be large.

[0089] When the operating conditions for this control are met, the braking force generated in the vehicle 100 is increased and corrected, shortening the braking distance traveled from the start of braking until the vehicle 100 comes to a stop, thereby assisting the driver's braking operation so that the vehicle can stop without colliding with an obstacle.

[0090] As described above, according to this embodiment 1, during the autonomous driving of the vehicle 100, even if there is an obstacle that could potentially collide with the vehicle 100 in its vicinity, the system fails to detect the obstacle due to a detection error by the surrounding situation recognition system. In such a situation, if the driver themselves discovers the obstacle and performs a braking operation that suggests an intention to avoid a collision, and the system detects that this braking operation was equivalent to a sudden brake, or that there was a possibility of a delay in the start of the braking operation, the braking force generated in the vehicle 100 is increased, making it possible to stop without colliding with the obstacle.

[0091] In the above-described Embodiment 1, an example was shown in which braking correction by the braking force increase control unit 30 is performed with a delay in brake operation as the triggering factor, but the triggering factors are not limited to this. In Embodiments 2 and later described below, examples are described in which the determination in step S406 in Figure 4 is made due to factors different from those in Embodiment 1, and the braking force increase control unit 30 is activated. The determinations in S404 and S405 in Figure 4 are made by the method described above, that is, it is assumed that a braking operation intended to avoid a collision has been performed in a situation in which the surrounding situation recognition system has not detected an obstacle that could potentially collide with the vehicle 100.

[0092] According to Embodiment 1 of the present invention, when the system fails to detect an obstacle during autonomous driving, it is possible to provide a driver assistance control device and a driver assistance control method that increase and correct the braking force when the driver performs a braking operation intended to avoid a collision, thereby enabling the vehicle to stop safely.

[0093] (Example 2) The control contents of the driver assistance control device in Example 2 of the present invention will be explained using the flowchart in Figure 8.

[0094] Figure 8 shows an overview of the operation of the steering operation determination unit 307. Following the flowchart in Figure 4, it is repeatedly executed when the vehicle 100 is in automatic driving mode. When the steering control amount exceeds a threshold, it determines that a collision avoidance operation has been performed by the driver's steering and requests the operation of the braking force increase control unit 30.

[0095] In step S801, the amount of steering control by the driver is obtained from the electric power steering system 6.

[0096] In step S802, the steering control unit 24 determines whether the detected steering control amount is greater than or equal to the threshold Th4. If it is greater than or equal to the threshold Th4, it is determined that a collision avoidance operation was performed by the driver's steering, and the process proceeds to step S803. If it is less than the threshold Th4, the process proceeds to step S804.

[0097] Here, the threshold Th4 may be set as a value assumed to be the amount of steering control performed by the driver to avoid collision with an obstacle near the vehicle 100 or in the direction of travel. However, if the automatic parking control is deactivated when a steering operation by the driver exceeding a predetermined value is detected, the threshold Th4 is set to a value less than or equal to the predetermined value. This is because the steering operation determination in Figure 8 is a process that is performed only during automatic driving, and the determination in step S802 is not made after automatic driving is deactivated.

[0098] In step S803, since the driver intervenes in the steering control which is left to the system during autonomous driving, it can be inferred that the driver sensed danger and attempted a collision avoidance maneuver by steering to initiate a collision with an obstacle. Therefore, the activation request for the braking force increase control unit 30 is set to ON. This sends an activation request for auxiliary control to the braking force increase control unit 30.

[0099] In step S804, it is determined that the driver has not attempted to avoid a collision with an obstacle by steering the vehicle 100, so the request to activate the braking force increase control unit 30 is turned OFF.

[0100] As described above, according to this embodiment 2, the same effects as in embodiment 1 can be obtained. In addition, when the driver performs a steering operation, the system reads the driver's intention to avoid a collision with a nearby obstacle that could not be detected by the system, and when collision avoidance is performed by emergency braking including steering control, the braking force generated by the brake operation is increased, thereby enabling collision avoidance with the obstacle.

[0101] (Example 3) The control contents of the driver assistance control device in Example 3 of the present invention will be explained using the flowchart in Figure 9.

[0102] Figure 9 shows an overview of the sonar obstacle detection and determination unit 305. Following the flowchart in Figure 4, this unit is repeatedly executed when the vehicle 100 is in autonomous driving mode. When the system changes from detecting the presence of an obstacle that could potentially collide with the vehicle 100 to not detecting an obstacle, it determines that there was actually an obstacle near the vehicle 100, and therefore the likelihood of collision with the obstacle is high, and requests the operation of the braking force increase control unit 30.

[0103] In step S901, the collision prediction unit 22 acquires the detection status of an obstacle that could potentially collide with the vehicle 100 in its vicinity.

[0104] In step S902, the acquired obstacle detection status is compared with the previous value of the acquired detection status. If the system has changed from detecting an obstacle to not detecting one, the system proceeds to step S903; otherwise, the system proceeds to step S904 for further determination.

[0105] In step S903, unlike the case where no obstacle was detected from the beginning, it is highly likely that the system lost sight of the obstacle even though an obstacle actually exists near the vehicle 100, and it can be inferred that this is a dangerous situation. Therefore, the operation request output from the operation request determination unit 308 of the power increase control unit 30 is set to ON (the operation request determination unit 308 outputs an operation request for auxiliary control of braking force to the target braking force calculation unit 311).

[0106] In step S904, if the surrounding environment recognition system detects the presence of an obstacle, or if a predetermined time has elapsed since the control operation request in this process was turned ON, the process proceeds to step S905; otherwise, the process proceeds to step S906.

[0107] In step S905, since the system has detected an obstacle, it can be inferred that a collision with the potentially colliding obstacle can be avoided using, for example, a known automatic braking system such as AEB, or that the obstacle has moved away from the vehicle 100 and therefore the operation of the present invention is unnecessary. In this case, the operation request output from the operation request determination unit 308 in the braking force increase control 30 is turned OFF.

[0108] In step S906, since there was no change in the obstacle detection status, the operation request retains the previous value.

[0109] Furthermore, in this embodiment 3, when the braking force increase control unit 30 is activated due to a change in the obstacle detection state to non-detection, the obstacle information that was detected until immediately before has been lost. Therefore, it is assumed that there is a high possibility that an obstacle is actually present near the vehicle 100, and the risk of collision is also high. For this reason, the braking force increased by the control operation may be set to a high value.

[0110] As described above, according to this embodiment 3, the same effects as in embodiment 1 can be obtained. Furthermore, even in situations where the detection accuracy of the surrounding situation recognition system decreases, causing the previously detected obstacle to be lost and the deceleration or braking control for the obstacle to be released at an unintended timing, the possibility of collision with the obstacle can be reduced by increasing the braking force of the driver's brake.

[0111] Furthermore, by turning the activation request OFF after a certain period of time has elapsed since the activation request was turned ON, care can be taken to prevent malfunctions that could cause discomfort to the driver, such as when the detected obstacle moves away from the vehicle 100, even though the actual risk of collision has been eliminated and the activation request continues to be issued.

[0112] (Example 4) The control contents of the driver assistance control device in Example 4 of the present invention will be explained using the flowchart in Figure 10. Figure 10 shows an overview of the operation of the obstacle detection difficulty determination unit 302, which is repeatedly executed when the vehicle 100 is in automatic driving mode, according to the flowchart in Figure 4, and determines whether it will be difficult for the vehicle 100 to detect obstacles with its sensors based on the path the vehicle 100 is traveling on and information about its surroundings, and requests the operation of the braking force increase control unit 30.

[0113] In step S1001, the route information generated by the route generation unit 23 is acquired.

[0114] In step S1002, the steering angle instruction value generated by the steering control unit 24 is acquired.

[0115] In step S1003, it is determined from the acquired route information whether the vehicle 100 is reversing or not. If the vehicle 100 is reversing, the process proceeds to step S1004; otherwise, if it is not reversing, i.e., moving forward, the process proceeds to step S1007.

[0116] In step S1004, the difficulty of detecting obstacles by the obstacle detection units 2 and 3 is determined, limited to when the vehicle 100 is reversing. If it is determined that it is difficult to find an obstacle, the process proceeds to step S1005. If it is determined that it is not difficult to find an obstacle, the process proceeds to step S1006.

[0117] Here, there may be multiple indicators for determining that obstacle detection is difficult. For example, a system called sonar 3 is installed to detect obstacles, but the detection range of sonar 3 when reversing is set to a certain range in a fan shape from behind the vehicle 100. Therefore, if the vehicle 100 travels along a reverse path with a large curvature, the detection range of sonar 3 changes significantly, and it may be determined that it is difficult to detect obstacles.

[0118] Here, the curvature of the path used as the criterion for judgment may be set based on a value that allows for some margin in the minimum turning radius of the vehicle 100, and the specific value may differ depending on the characteristics of the vehicle 100. The above criterion may also be made by steering angle instruction values, and it may be determined that it is difficult to detect an obstacle when reversing with a large point steering angle.

[0119] Furthermore, when acquiring surrounding map information of the vehicle 100 from the external information sensor device 19, and driving on a route with narrow roads or frequent intersections such as in residential areas, the detection range of the surrounding situation recognition system and the driver's field of view are both limited, making it possible to determine that obstacle detection is difficult.

[0120] In step S1005, since it is difficult for the vehicle 100 to detect obstacles while driving, it may take time to recognize the presence of obstacles, potentially delaying brake operation. Therefore, the activation request for auxiliary braking control of the braking force increase control unit 30 is set to ON (an activation request for auxiliary control is sent). Furthermore, in this embodiment 4, when the vehicle 100 is traveling along a path with a large curvature, the driver's field of view and the detection range of the surrounding situation recognition system change significantly, and the effect is expected to increase with the distance traveled. Therefore, when the braking force increase control unit 30 is activated due to the determination in this process, the braking force generated in the vehicle 100 may be set to a larger value than usual.

[0121] In step S1006, it is determined that there are few factors that hinder the detection of obstacles, so the braking force increase correction according to the present invention is deemed unnecessary, and the control operation request is turned OFF.

[0122] In step S1007, when the vehicle 100 is moving forward, the driver's visibility is good and the blind spot area is smaller than when reversing, so it is determined that the braking force increase correction according to the present invention is unnecessary, and the control operation request is turned OFF.

[0123] As described above, according to this embodiment 4, the same effects as in embodiment 1 can be obtained, and in situations where the detection range of the surrounding situation recognition system changes significantly, and the number of blind spots from the driver's perspective increases, making it difficult to detect obstacles, even if there is a delay in braking operation due to a delay in obstacle detection, the braking force can be increased and corrected, increasing the possibility of stopping the vehicle 100 without colliding with an obstacle that is suddenly detected.

[0124] (Example 5) The control contents of the driver assistance control device in Example 5 of the present invention will be explained using the flowchart in Figure 11.

[0125] Figure 11 shows an overview of the operation of the visibility deterioration determination unit 301. Following the flowchart in Figure 4, it is repeatedly executed when the vehicle 100 is in autonomous driving mode. Based on information from the surrounding environment and various sensors, it determines whether the driver's visibility has deteriorated and whether it is difficult to visually detect obstacles, and requests the operation of the braking force increase control unit 30.

[0126] In step S1101, information about the vehicle environment 100 and various sensors is detected and acquired, such as the operating status of at least one of the following: the rain sensor 13, the wiper switch 14, or the headlights 15. Specifically, the visibility deterioration determination unit 301 acquires information that allows for the determination of whether the driver's visibility has deteriorated due to reasons such as the detection status of rainfall, nighttime conditions, or reduced light levels. This information may be estimated, for example, from the operating status of the interior lights or the time elapsed since sunset, or if the camera 2 detects clouding and becomes inoperable, it may be determined that visibility has deteriorated.

[0127] In step S1102, it is determined whether or not it is difficult for the driver to visually detect an obstacle. If it is difficult to detect an obstacle, the process proceeds to step S1103; otherwise, the process proceeds to step S1104. Here, when the headlights are on, it may be determined that the driver's visibility deteriorates due to sunset or a decrease in ambient light, making it difficult to visually detect an obstacle.

[0128] Furthermore, even in situations where it can be inferred that it is raining, such as when the rain sensor 13 detects rainfall or when the wipers are operating via the wiper switch 14, the driver's visibility is similarly impaired, making it difficult to detect obstacles.

[0129] Furthermore, if the image captured by camera 2 is cloudy, it can be inferred that visibility is poor due to fog, and therefore it can be judged that it is difficult to detect obstacles.

[0130] Under these circumstances, it becomes difficult for the driver to detect obstacles, and as a result of the delay in detecting obstacles, braking may be delayed. Therefore, it is desirable to activate the braking force increase control unit 30 with the intention of increasing braking force.

[0131] In step S1103, in order to compensate for the delay in braking operation due to the delay in detecting the obstacle as described above, the activation request for the braking force increase control unit 30 is turned ON (an activation request for auxiliary control of braking force is sent to the braking force increase control unit 30). Furthermore, in this embodiment 5, since multiple factors that worsen visibility may occur simultaneously, and the difficulty of detecting obstacles is expected to increase depending on the combination of these factors, when the braking force increase control unit 30 is activated due to the determination in this process, the braking force generated on the vehicle 100 may be set to a larger value than normal, depending on the number of factors that are considered to worsen visibility that are occurring simultaneously.

[0132] In step S1104, since the driver's visibility is good, it is determined that the braking force increase correction according to the present invention is unnecessary, and the control operation request is turned OFF.

[0133] As described above, this embodiment 5 provides the same effects as embodiment 1. Furthermore, by activating the braking force increase control 30 in situations where the driver's visibility is poor and it is presumed that it is difficult to visually detect obstacles, it is possible to compensate for the delay in braking operation due to the delay in detecting obstacles and reduce the possibility of collision with obstacles.

[0134] (Example 6) The control contents of the driver assistance control device in Example 6 of the present invention will be explained using the flowchart in Figure 12.

[0135] Figure 12 shows an overview of the camera recognition and determination unit 304. Following the flowchart in Figure 4, the unit repeatedly executes when the vehicle 100 is in autonomous driving mode. The camera recognition and determination unit 304 analyzes the image information captured by the camera 2, and when it detects a brightness difference greater than a predetermined amount, it determines that there is a possibility of some kind of object (obstacle) being present and requests the operation of the braking force increase control unit 30.

[0136] In step S1201, image information captured by camera 2 is acquired. Here, image acquisition may target all cameras 2 in the front, back, left, and right directions, or it may target only the camera corresponding to the direction of travel.

[0137] In step S1202, the acquired camera image is analyzed to check if there is a difference in brightness greater than a certain level. Here, the information of the acquired image is checked pixel by pixel along a certain direction, and if a difference in brightness greater than a certain level occurs as a result, it can be determined that a boundary exists between objects at that location.

[0138] Taking the example of autonomous parking of vehicle 100, if a fence is present behind vehicle 100, even if the sonar 3 cannot detect the presence of the fence, if a certain level of brightness difference can be detected from the image captured by camera 2, the boundary point can be detected from the brightness difference between the road surface and the fence. The above example is effective for objects with high transparency such as fences, but it is also effective for other objects that are difficult for sonar 3 to detect, such as children or low objects such as curbs.

[0139] Here, the threshold for brightness difference used for object boundary detection is set to a value that does not over-detect variations in road surface density, etc., because the recognition accuracy of camera 2 may depend on the performance of the camera mounted on the vehicle 100.

[0140] In step S1203, if a difference in brightness of a certain magnitude or greater is detected in the camera image along the planned route, that is, if it can be determined that a boundary exists between objects, the system proceeds to step S1204. If no difference in brightness is detected in the image, the system proceeds to step S1205.

[0141] In step S1204, the operation request for the braking force increase control unit 30 is turned ON (an operation request is sent) in order to avoid a collision with an object that is presumed to be present on the planned travel route.

[0142] In step S1205, since no object is detected, it is determined that the braking force increase correction according to the present invention is unnecessary, and the control operation request is turned OFF.

[0143] As described above, according to this embodiment 6, the same effects as in embodiment 1 can be obtained. Furthermore, even when the sonar 3 is unable to detect an obstacle due to performance limitations or other reasons, if the camera 2 can infer the presence of an object that appears to be an obstacle from the difference in brightness between objects, it is possible to reduce the possibility of collision with that object by increasing the braking force in response to the driver's brake operation.

[0144] (Example 7) The control contents of the driver assistance control device in Example 7 of the present invention will be explained using the flowchart in Figure 13.

[0145] Figure 13 shows an overview of the route travel history determination unit 303. Following the flowchart in Figure 4, it is repeatedly executed when the vehicle 100 is in autonomous driving mode, and creates a map that estimates the risk of collision with obstacles based on the vehicle 100's travel history and surrounding information such as map information. When traveling through an area where the risk of collision is estimated to be high, such as an untraveled route, it determines that there is a possibility of collision with an obstacle and requests the operation of the braking force increase control unit 30. The route travel history determination unit 303 stores the vehicle 100's travel history and determines whether or not the travel route generated by the route generation unit 23 includes the route history.

[0146] In step S1301, the route travel history, described later, and map information of the roads around the vehicle 100 are obtained from the external information sensor device 19.

[0147] In step S1302, a collision risk map is created that categorizes the risk of collision with obstacles based on the information described above. The risk of collision with obstacles may be estimated, for example, by the driving history of the route. If the surrounding situation recognition system does not estimate the presence of obstacles when the vehicle 100 is driving, the driving trajectory and surrounding area may be judged and set as a safe zone with a low risk of collision.

[0148] On the other hand, if the approach of an obstacle is detected, or if the presence of an obstacle (for example, a vehicle that has already stopped) is foreseen near the vehicle 100, the surrounding area may be judged as a high-risk zone for collision. Similarly, if the driver applies the brakes, the area may be considered a high-risk zone for collision because it is presumed that some object may be present.

[0149] Furthermore, for areas that the vehicle 100 has not yet traveled through, these are unassessed areas where safety checks have not been performed by the driver and the surrounding situation recognition system. Therefore, the collision risk for these areas may be set to unknown or high.

[0150] Collision risk can be estimated using surrounding information such as map data, and a higher collision risk may be set when driving on roads with poor visibility, such as in residential areas or parking lots, especially at intersections in residential areas. This can be done by using the accident rate associated with the map data, and setting a higher collision risk in locations with a high accident rate.

[0151] In step S1303, it is determined whether to travel within the area deemed safe on the collision risk map created in step S1302 for the planned travel route up to a certain distance. If the vehicle travels within a safe area, it proceeds to step S1304. If the vehicle travels outside a safe area, specifically in an area where the collision risk is unknown or deemed high, it proceeds to step S1305.

[0152] In step S1304, the operation request for the braking force increase control unit 30 is turned OFF because the vehicle will be traveling through an area that has already been confirmed to be safe.

[0153] In step S1305, when driving in an area where the risk of collision is unknown or high, the activation request for the braking force increase control unit 30 is turned ON (a request for the braking force increase control unit 30 to activate auxiliary control of the braking force is transmitted) in order to avoid collisions with objects that suddenly jump out from behind an object or objects that are detected late.

[0154] As described above, this embodiment 7 provides the same effects as embodiment 1. Furthermore, by creating a map that estimates collision risk from the driving history of the route, it is possible to reduce the discomfort to the driver caused by unnecessary control operations when passing through a section that has already been driven and is easily estimated to be safe. This is effective, for example, in situations where the vehicle passes through the same location multiple times, such as when parking.

[0155] Furthermore, by pre-setting collision risks for untraveled routes based on map information, it becomes possible to appropriately increase braking force in situations where danger is foreseeable.

[0156] 2B, 2F, 2L, 2R... On-board camera, 3... Sonar, 6... Electric power steering system, 7FL, 7FR, 7RL, 7RR... Wheels, 8FL, 8FR, 8RL, 8RR... Wheel speed sensor, 9... On-board display device, 10... Autonomous driving ECU, 11... Vehicle control ECU, 12... Brake pedal (braking system), 12s... Stroke sensor, 13... Rain sensor, 14... Wiper switch, 15... Headlights, 18... Steering wheel, 19... External information sensor device, 21... Vehicle position estimation unit, 22... 23...Collision prediction unit, 24...Path generation unit, 30...Steering control unit, 31...Drive support control unit (braking force increase control unit), 100...Self-vehicle, 300...Control operation determination unit, 301...Visibility deterioration determination unit, 302...Obstacle detection difficulty determination unit, 303...Route driving history determination unit, 304...Camera recognition determination unit, 305...Sonar obstacle detection determination unit, 306...Brake operation determination unit (braking force detection unit), 307...Steering operation determination unit (braking force detection unit), 308...Operation request determination unit, 311...Target braking force calculation unit

Claims

1. A driver assistance control device that performs automatic driving by assisting at least vehicle speed control and position control among the operation control of a vehicle, comprising: a braking force detection unit that detects when the driver of the vehicle has activated the vehicle's braking device; an operation request determination unit that determines whether or not to assist the braking force of the braking device generated in the vehicle when the braking force detection unit detects the activation of the braking device; an external information detection unit that detects obstacles in the vicinity of the vehicle; and a braking force increase control unit that controls the increase of the braking force of the braking device, wherein the operation request determination unit determines whether or not an operation to avoid collision with the obstacle has been performed based on the detection result of the braking force detection unit's detection of the activation of the braking device, and when the external information detection unit has not detected the obstacle, and the driver of the vehicle has activated the vehicle's braking device and performed an operation to avoid collision with the obstacle, the driver assistance control device of the braking force increase control unit is performed to assist the braking force of the braking device.

2. A driver assistance control device according to claim 1, wherein the braking device is the brake pedal of the vehicle, and the braking force detection unit detects the amount of depression of the brake pedal and the amount of change of the depression from a stroke sensor that detects the stroke or brake pressure of the brake pedal, and when the amount of depression is greater than or equal to a predetermined value and the amount of change of the depression falls within a predetermined range, the driver assistance control device is characterized in that it notifies the operation request determination unit that an emergency braking operation by the brake pedal has been detected.

3. A driver assistance control device according to claim 2, wherein the braking force detection unit detects the speed at which the brake pedal is pressed and detects the amount of change in the amount of pressing.

4. A driver assistance control device according to claim 2, wherein the braking force detection unit transmits a request to the braking force increase control unit to activate the braking force when the brake pressure or stroke is not detected, or when the amount of change in the amount of depression is greater than the predetermined range.

5. A driver assistance control device according to claim 1, comprising a steering control unit for detecting the amount of steering control performed by the driver of the vehicle, wherein the steering control unit determines that a collision avoidance operation has been performed by the driver when the amount of steering control performed by the driver exceeds a certain value, and transmits a request for the operation of auxiliary control to the braking force increase control unit.

6. A driver assistance control device according to claim 1, comprising an obstacle detection unit for detecting an obstacle in the vicinity of the vehicle, wherein the obstacle detection unit stops the auxiliary control of the braking force from the operation request determination unit after a predetermined time has elapsed since detecting the obstacle, and outputs an operation request for the auxiliary control of the braking force from the operation request determination unit when the state changes from one in which the obstacle was detected to one in which the obstacle is not detected.

7. A driver assistance control device according to claim 1, comprising: an obstacle detection unit for detecting an obstacle in the vicinity of the vehicle; a route generation unit for creating information on the route the vehicle will travel; a steering control unit for calculating the steering angle instruction value necessary for the vehicle to travel the planned route; and an obstacle detection difficulty determination unit, wherein the obstacle detection difficulty determination unit determines whether it is difficult for the obstacle detection unit to detect the obstacle based on the route information and the steering angle instruction value, and if it determines that it is difficult to detect the obstacle, it transmits a request to the braking force increase control unit to activate auxiliary control of the braking force.

8. A driver assistance control device according to claim 1, comprising a visibility deterioration determination unit that detects the operating state of at least one of a wiper switch, a headlight, or a rain sensor, wherein the visibility deterioration determination unit, when it determines that obstacle detection will be difficult based on the operating state, transmits a request to the braking force increase control unit to operate auxiliary control of the braking force.

9. A driver assistance control device according to claim 1, comprising: a camera for photographing the area around the vehicle; and a camera recognition determination unit for determining the presence of an obstacle based on an image captured by the camera, wherein the camera recognition determination unit, based on the image information captured by the camera, determines that there is an obstacle on the planned driving path if it detects a difference in brightness of a certain level or more on the planned driving path of the vehicle, and transmits a request for the brake force increase control unit to activate auxiliary control of the brake force.

10. A driver assistance control device according to claim 1, comprising: a route generation unit that creates information on a route the vehicle will travel; and a route travel history determination unit that stores the route history of the vehicle and determines whether or not the route history is included in the route generated by the route generation unit, wherein the route travel history determination unit transmits a request for the brake force increase control unit to activate auxiliary control of the brake force if the route history is not included in the route.

11. A driver assistance control method that assists at least vehicle speed control and position control among the vehicle's operation control and performs autonomous driving, characterized in that, during autonomous driving, it is determined whether or not an obstacle has been detected near the vehicle, and if no obstacle has been detected near the vehicle, it is detected that the driver has activated the vehicle's braking system, it is determined whether or not there is a possibility of collision between the vehicle and the obstacle, and if there is a possibility of collision between the vehicle and the obstacle, the braking system is made to provide assistance for the braking force of the vehicle.

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