Driving Support Devices

Abstract

To provide a driving support device capable of suppressing execution of deceleration support which gives a driver a sense of incongruity at the time of brake release.SOLUTION: A driving support device for executing deceleration support of an own vehicle, includes: a deceleration target detecting unit for detecting a deceleration target in front of the own vehicle based on a detection result of an external sensor of the own vehicle; a relative situation recognizing unit for recognizing a relative situation between the deceleration target and the own vehicle based on the detection result of the external sensor of the own vehicle; and a deceleration support execution unit for executing the deceleration support of the own vehicle when the relative situation between the deceleration target and the own vehicle satisfies a preset deceleration support precondition and when an acceleration operation and a brake operation of a driver of the own vehicle are not performed. When the deceleration support is not started due to the brake operation being performed although the deceleration support execution unit satisfies the deceleration support precondition, the deceleration support execution unit does not perform the deceleration support until a certain amount of time has passed from the end of the brake operation.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a driving assistance device. [Background technology]

[0002] Conventionally, JP 2013-218429 A is known as a technical document related to a driving assistance device. This publication describes that in a driving assistance device that performs deceleration assistance based on the distance to a stop line (a deceleration target) of the host vehicle and the vehicle speed of the host vehicle, the deceleration assistance is terminated when conditions such as the distance to the stop line of the host vehicle are no longer satisfied. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-218429 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, there is a known technique for deceleration support that does not start deceleration support when the driver is braking even if the conditions such as the distance to the stop line of the vehicle are satisfied, and starts deceleration support after the brake is released. However, since the driver may not have the intention to decelerate when the brake is released, there is a risk that the execution of deceleration support may cause the driver discomfort. [Means for solving the problem]

[0005] One aspect of the present invention is a driving assistance device that performs deceleration assistance for a host vehicle, the device including: a deceleration object detection unit that detects a deceleration object in front of the host vehicle based on a detection result of an external sensor of the host vehicle; a relative situation recognition unit that recognizes a relative situation between the deceleration object and the host vehicle based on the detection result of the external sensor of the host vehicle; and a deceleration assistance execution unit that performs deceleration assistance for the host vehicle when the relative situation between the deceleration object and the host vehicle satisfies a pre-set deceleration assistance precondition and the driver of the host vehicle is not performing an accelerator operation or a brake operation. In a case where the deceleration assistance precondition is satisfied but deceleration assistance is not started because the brake is being operated, the deceleration assistance execution unit performs deceleration assistance until a certain time has elapsed since the brake is released. Without , The certain time is set to a different value depending on the type of deceleration target. The types of deceleration target include a curve, an automobile, a bicycle, and a pedestrian. The certain time is set to be shorter when the deceleration target is an automobile than when the deceleration target is a curve, and the certain time is set to be shorter when the deceleration target is a bicycle or a pedestrian than when the deceleration target is an automobile. The certain time is set to be shorter the higher the vehicle speed of the host vehicle. . Effect of the Invention

[0006] According to one aspect of the present invention, it is possible to prevent deceleration assistance that gives a sense of discomfort to the driver when the brakes are released from being executed. [Brief description of the drawings]

[0007] [Figure 1] 1 is a block diagram showing a driving assistance device according to an embodiment; [Diagram 2] 11 is a table showing an example of a relationship between an assistance sensitivity and a deceleration assistance prohibition time. [Diagram 3] 10 is a flowchart illustrating an example of a deceleration support start process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0009] A driving assistance device 100 shown in FIG. 1 is a device mounted on a vehicle (host vehicle) such as a passenger car, and assists a driver in driving the host vehicle. When a deceleration target such as a preceding vehicle or a traffic light is detected ahead of the host vehicle, the driving assistance device 100 performs deceleration support for the host vehicle under a predetermined condition. The deceleration target is an object for which deceleration support is performed. The deceleration target includes a curve. The deceleration target may include another vehicle. The deceleration target may include a pedestrian or a bicycle, and may also include a traffic light, a stop line, a crosswalk, a fallen object, a construction installation, a structure, and the like.

[0010] The deceleration support is, for example, a driving support that decelerates the host vehicle to a preset target vehicle speed. The target vehicle speed is not particularly limited and may be 0 km / h or 10 km / h. The target vehicle speed may be determined according to the type of the deceleration target. When the deceleration target is a traffic light, the target vehicle speed for the deceleration support may be changed according to the illumination state of the traffic light (illumination state of green light, yellow light, red light, etc.). When the deceleration target is a moving object such as a preceding vehicle, the target vehicle speed is not limited to the speed of the host vehicle, and the relative speed between the host vehicle and the deceleration target may be used. The deceleration support may be performed according to a target deceleration pattern that is a time change of the target deceleration, instead of the target vehicle speed.

[0011] [Configuration of driving assistance device] The configuration of the driving assistance device 100 will be described below with reference to the drawings. As shown in FIG. 1, the driving assistance device 100 includes a driving assistance ECU (Electronic Control Unit) 10 that performs overall management of the device. The driving assistance ECU 10 is an electronic control unit having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. In the driving assistance ECU 10, for example, various functions are realized by the CPU executing a program stored in the ROM. The driving assistance ECU 10 may be composed of multiple electronic units.

[0012] The driving assistance ECU 10 is connected to an external sensor 1, an internal sensor 2, an accelerator pedal sensor 3, a brake pedal sensor 4, and an actuator 5.

[0013] The external sensor 1 is a detection device that detects the situation around the vehicle. The external sensor 1 includes at least one of a camera and a radar sensor. The camera is an imaging device that captures an image of the external situation of the vehicle. The camera is provided, for example, on the back side of the windshield of the vehicle, and captures an image in front of the vehicle. The camera transmits imaging information related to the external situation of the vehicle to the driving assistance ECU 10. The camera may be a monocular camera or a stereo camera.

[0014] A radar sensor is a detection device that detects objects around the vehicle using radio waves (e.g., millimeter waves) or light. Radar sensors include, for example, millimeter wave radars and LIDARs (Light Detection and Ranging). The radar sensor detects objects by transmitting radio waves or light to the surroundings of the vehicle and receiving the radio waves or light reflected by the objects. The radar sensor transmits information about the detected objects to the driving assistance ECU 10.

[0015] The internal sensor 2 is a detection device that detects the traveling state of the host vehicle. The internal sensor 2 includes a vehicle speed sensor, an acceleration sensor, and a yaw rate sensor. The vehicle speed sensor is a detector that detects the speed of the host vehicle. As the vehicle speed sensor, for example, a wheel speed sensor that is provided on the wheels of the host vehicle or a drive shaft that rotates integrally with the wheels and detects the rotation speed of the wheels is used. The vehicle speed sensor transmits the detected vehicle speed information (wheel speed information) to the driving assistance ECU 10.

[0016] The acceleration sensor is a detector that detects the acceleration of the host vehicle. The acceleration sensor includes, for example, a longitudinal acceleration sensor that detects the acceleration in the longitudinal direction of the host vehicle, and a lateral acceleration sensor that detects the lateral acceleration of the host vehicle. The acceleration sensor transmits, for example, acceleration information of the host vehicle to the driving assistance ECU 10. The yaw rate sensor is a detector that detects the yaw rate (rotational angular velocity) around the vertical axis of the center of gravity of the host vehicle. For example, a gyro sensor can be used as the yaw rate sensor. The yaw rate sensor transmits the detected yaw rate information of the host vehicle to the driving assistance ECU 10.

[0017] The accelerator pedal sensor 3 is provided, for example, on a shaft portion of an accelerator pedal of the host vehicle and detects the amount of depression of the accelerator pedal. The accelerator pedal sensor 3 transmits an accelerator operation signal corresponding to the detected amount of depression of the accelerator pedal to the driving assistance ECU 10.

[0018] The brake pedal sensor 4 is provided, for example, on a shaft portion of a brake pedal of the host vehicle and detects the amount of depression of the brake pedal. The brake pedal sensor 4 transmits a brake operation signal corresponding to the detected amount of depression of the brake pedal to the driving assistance ECU 10.

[0019] The actuator 5 is a device used to control the host vehicle. The actuator 5 includes at least a drive actuator and a brake actuator. The actuator 5 may include a steering actuator. The drive actuator controls the amount of air supplied to the engine (throttle opening) in response to a control signal from the driving assistance ECU 10, thereby controlling the driving force of the host vehicle. If the host vehicle is a hybrid vehicle, in addition to the amount of air supplied to the engine, a control signal from the driving assistance ECU 10 is input to a motor serving as a power source to control the driving force. If the host vehicle is an electric vehicle, a control signal from the driving assistance ECU 10 is input to a motor serving as a power source to control the driving force. The motor serving as a power source in these cases constitutes the actuator 5.

[0020] The brake actuator controls a brake system in response to a control signal from the driving assistance ECU 10, and controls the braking force applied to the wheels of the vehicle. For example, a hydraulic brake system can be used as the brake system. The steering actuator controls the drive of an assist motor that controls the steering torque of the electric power steering system in response to a control signal from the driving assistance ECU 10. In this way, the steering actuator controls the steering torque of the vehicle.

[0021] Next, a description will be given of the functional configuration of the driving assistance ECU 10. As shown in Fig. 1, the driving assistance ECU 10 has a deceleration target detection unit 11, a relative situation recognition unit 12, a start condition determination unit 13, and a deceleration assistance execution unit 14. Note that some of the functions of the driving assistance ECU 10 described below may be executed by a server capable of communicating with the vehicle.

[0022] The deceleration target detection unit 11 detects a deceleration target such as a preceding vehicle ahead of the vehicle based on the detection result of the external sensor 1. The deceleration target detection unit 11 detects a deceleration target ahead of the vehicle based on an image captured by a camera or object information from a radar sensor.

[0023] The deceleration object detection unit 11 detects deceleration objects such as curves, traffic lights, stop lines, and preceding vehicles by performing pattern matching using pre-stored image patterns for each type of deceleration object based on a captured image of the area ahead of the vehicle captured by a camera, for example. When the deceleration object is a curve, for example, the deceleration object detection unit 11 can detect the curve by recognizing the curvature of the road from a captured image of white lines on the road using a well-known image processing technique. The curve as the deceleration object can be a section with a curvature of a certain value (for example, 60R) or more.

[0024] The relative situation recognition unit 12 recognizes the relative situation between the host vehicle and the deceleration target. The relative situation includes at least the distance between the host vehicle and the deceleration target (the distance in the front-rear direction or the traveling direction of the host vehicle). The relative situation may include the relative speed between the host vehicle and the deceleration target, the time to collision [TTC: Time To Collusion] of the host vehicle with the deceleration target, and the time headway [THW: Time Headway].

[0025] The relative situation recognition unit 12 recognizes the relative situation between the vehicle and the deceleration target based on, for example, the detection result of the external sensor 1. When the deceleration target is a vehicle capable of vehicle-to-vehicle communication with the vehicle, the relative situation recognition unit 12 may recognize the relative situation between the vehicle and the deceleration target using information acquired through vehicle-to-vehicle communication. The relative situation recognition unit 12 may recognize the relative speed between the vehicle and the deceleration target based on, for example, the speed of the deceleration target and the speed of the vehicle acquired through vehicle-to-vehicle communication. The relative situation recognition unit 12 may use the detection result of the internal sensor 2 (detection result of the vehicle speed sensor) to recognize the relative speed between the vehicle and the deceleration target when, for example, the position of the deceleration target is fixed.

[0026] The start condition determination unit 13 determines whether or not a deceleration support precondition for a deceleration target is satisfied. The deceleration support precondition is a precondition that is set in advance for use in determining whether or not to start deceleration support. The start condition determination unit 13 determines whether or not the deceleration support precondition is satisfied based on at least the distance between the vehicle and the deceleration target.

[0027] The deceleration support precondition may be changed according to the type of deceleration target. For example, when the deceleration target is a curve, the start condition determination unit 13 determines whether or not the deceleration support precondition is satisfied based on the distance to the entrance of the curve of the host vehicle and the vehicle speed of the host vehicle. As an example, the start condition determination unit 13 determines that the deceleration support precondition is satisfied when the distance to the entrance of the curve of the host vehicle is less than the deceleration request threshold and the vehicle speed of the host vehicle is equal to or greater than the vehicle speed threshold. Each threshold used in the following description means a threshold value that is set in advance.

[0028] When the type of the deceleration target is a preceding vehicle, the start condition determination unit 13 may determine whether or not the deceleration support precondition for the preceding vehicle is satisfied based on the relative situation between the host vehicle and the deceleration target. Specifically, the start condition determination unit 13 determines that the deceleration support precondition for the preceding vehicle is satisfied when the speed of the host vehicle is greater than the speed of the preceding vehicle (positive value in the direction in which the relative speed approaches) and the collision margin time between the host vehicle and the preceding vehicle is less than the collision margin time threshold. The collision margin time is calculated by dividing the distance between the host vehicle and the deceleration target (preceding vehicle) by the relative speed (approaching speed) between the host vehicle and the deceleration target.

[0029] The start condition determination unit 13 may determine that the deceleration support precondition for the preceding vehicle is satisfied when the inter-vehicle time obtained by dividing the distance between the host vehicle and the preceding vehicle by the speed of the host vehicle becomes less than the inter-vehicle time threshold, instead of the collision margin time. The start condition determination unit 13 may determine that the deceleration support precondition for the preceding vehicle is satisfied when the distance between the host vehicle and the preceding vehicle is less than the distance threshold, instead of the collision margin time.

[0030] The start condition determination unit 13 may determine that the deceleration support precondition for the preceding vehicle is satisfied when the speed of the host vehicle is greater than the speed of the preceding vehicle and the required deceleration of the host vehicle is equal to or greater than the deceleration threshold. The required deceleration may be, for example, a deceleration required to prevent the distance between the host vehicle and the preceding vehicle from falling below a threshold value that is predetermined for each speed. The required deceleration may also be a deceleration required to prevent the distance between the host vehicle and the preceding vehicle from falling below a certain value.

[0031] When the type of deceleration target is a stop line, the start condition determination unit 13 may determine whether or not the deceleration assistance prerequisite for the stop line is satisfied based on the speed of the vehicle detected by the internal sensor 2 (vehicle speed sensor) and the relative situation of the vehicle and the stop line.

[0032] Specifically, the start condition determination unit 13 may determine that the deceleration support precondition for the stop line is satisfied when the speed of the host vehicle is equal to or greater than the support start speed threshold and the collision margin time between the host vehicle and the stop line is less than the collision margin time threshold. In this case, the collision margin time corresponds to the arrival time of the host vehicle at the stop line. The start condition determination unit 13 may determine that the deceleration support precondition for the preceding vehicle is satisfied when the distance between the host vehicle and the stop line is less than the distance threshold, instead of the collision margin time.

[0033] The start condition determination unit 13 may also determine that the deceleration support precondition for the stop line is satisfied when the speed of the host vehicle is equal to or greater than the support start speed threshold and the required deceleration of the host vehicle is equal to or greater than the deceleration threshold. The required deceleration in this case is, for example, a deceleration required for the host vehicle to stop at the stop line. The collision margin time threshold, distance threshold, and deceleration threshold may be different values ​​depending on the type of deceleration target.

[0034] When the type of the deceleration target is a traffic light, the start condition determination unit 13 may determine whether the deceleration support preconditions are satisfied for the stop line in front of the traffic light. When the type of the deceleration target is a traffic light and the external sensor 1 cannot detect the stop line in front of the traffic light due to rubbing of the white line of the stop line or the like, the start condition determination unit 13 determines whether the deceleration support preconditions are satisfied by assuming that a stop line exists at a position a certain distance before the traffic light.

[0035] When the type of deceleration target is a traffic light, the start condition determination unit 13 may determine whether or not the deceleration support precondition is satisfied based on the illumination state of the traffic light when the vehicle approaches the traffic light. The vehicle approaches the traffic light when, for example, the collision margin time of the vehicle at the position of the stop line in front of the traffic light or at a position a certain distance before the traffic light becomes less than the collision margin time threshold. Instead of the collision margin time, the inter-vehicle time may be used, or the distance between the vehicle and the position of the stop line (or a position a certain distance before the traffic light) may be used.

[0036] When the host vehicle approaches a traffic light, the start condition determination unit 13 determines whether the traffic light is in a passing permission state based on the detection result of the external sensor 1 (for example, an image captured by a camera). Here, the passing permission state means a state in which passing is permitted in the traveling direction of the traveling lane of the host vehicle. The traveling direction of the traveling lane of the host vehicle can be recognized from image recognition of an arrow (arrow painted on the road surface) shown on the road surface of the traveling lane or image recognition of a sign indicating the traveling direction of the traveling lane. The traveling direction of the traveling lane of the host vehicle may be recognized from the position of the host vehicle and map information (map information having traveling direction information for each lane).

[0037] When it is determined that the traffic light is not in a passing permitted state (when the traffic light is in a passing prohibited state or a transition state), the start condition determination unit 13 determines that the deceleration support precondition is satisfied.

[0038] When it is determined that the traffic light is in a passing permission state, the start condition determination unit 13 determines whether the host vehicle will turn right or left. The start condition determination unit 13 determines whether the host vehicle will turn right or left based on, for example, the traveling direction of the lane in which the host vehicle is traveling. The start condition determination unit 13 determines that the host vehicle will turn right or left when the lane in which the host vehicle is traveling is a left turn exclusive lane or a right turn exclusive lane. The start condition determination unit 13 may determine whether the host vehicle will turn right or left based on the illumination state of the direction indicator of the host vehicle.

[0039] The start condition determination unit 13 determines that the deceleration support precondition is satisfied when the traffic light is in a passing permission state and the host vehicle is determined to turn right or left. The start condition determination unit 13 determines that the deceleration support precondition is not satisfied when the traffic light is in a passing permission state and the host vehicle is not determined to turn right or left (when the vehicle travels straight).

[0040] The deceleration support execution unit 14 executes deceleration support when the start condition determination unit 13 determines that the deceleration support preconditions are satisfied and that the driver is not operating the accelerator or the brake. Deceleration support is control that supports the deceleration of the host vehicle relative to a deceleration target. The deceleration support is executed by controlling a brake actuator so that the deceleration of the host vehicle becomes a target deceleration that is preset according to, for example, the relative situation between the host vehicle and the deceleration target (distance, relative speed, time to collision, etc.).

[0041] When it is determined that the deceleration support precondition is satisfied, the deceleration support execution unit 14 determines that the driver is not operating the accelerator, based on the accelerator operation signal of the accelerator pedal sensor 3. When, for example, the amount of depression of the accelerator pedal by the driver is less than the accelerator operation threshold, the deceleration support execution unit 14 determines that the driver is not operating the accelerator.

[0042] Similarly, when the deceleration support execution unit 14 determines that the deceleration support precondition is satisfied, it determines that the driver is not braking based on the brake operation signal of the brake pedal sensor 4. For example, when the amount of depression of the brake pedal by the driver is less than the brake operation threshold, the deceleration support execution unit 14 determines that the driver is not braking. On the other hand, when the amount of depression of the brake pedal by the driver is equal to or greater than the brake operation threshold, the deceleration support execution unit 14 determines that the driver is braking.

[0043] When the start condition determination unit 13 determines that the deceleration support preconditions are satisfied but deceleration support is not started because the driver is braking, the deceleration support execution unit 14 determines whether the driver has released the brakes. Brake release refers to, for example, the amount of depression of the brake pedal by the driver changing from equal to or greater than the accelerator operation threshold to less than the brake operation threshold.

[0044] When it is determined that the driver has released the brakes, the deceleration support execution unit 14 does not execute deceleration support until a certain period of time has elapsed since the brakes were released. The certain period of time refers to a deceleration support prohibition period during which deceleration support is not executed.

[0045] The certain time may be a fixed value or may be a value set by the driver. The driver may change the certain time (deceleration support prohibited time) by, for example, setting the support sensitivity of the deceleration support. For example, the certain time is set to a shorter time as the support sensitivity of the deceleration support is higher.

[0046] FIG. 2 is a diagram showing an example of the relationship between the support sensitivity of deceleration support and the deceleration support prohibition time. As shown in FIG. 2, when the support sensitivity of deceleration support set for the driver is "weak", the deceleration support prohibition time can be set to, for example, 4 seconds. When the support sensitivity of deceleration support set for the driver is "medium", the deceleration support prohibition time can be set to, for example, 3 seconds. When the support sensitivity of deceleration support set for the driver is "high", the deceleration support prohibition time can be set to, for example, 2 seconds. The support sensitivity of deceleration support may be the same as the support sensitivity of the overall driving support.

[0047] The certain time may be set to a different value depending on the type of deceleration target (curve, automobile, bicycle, pedestrian, etc.). The certain time (deceleration support prohibited time) may be shorter when the deceleration target is an automobile compared to when the deceleration target is a curve. The certain time may be shorter when the deceleration target is a bicycle or pedestrian compared to when the deceleration target is an automobile. The certain time may be shorter the higher the vehicle speed of the host vehicle.

[0048] [Driving assistance device processing] Next, the process of the driving support device 100 according to this embodiment will be described with reference to the drawings. Fig. 3 is a flowchart showing an example of the deceleration support start process. This deceleration start process is performed when the driving support function is being executed.

[0049] As shown in Fig. 3, the driving assistance ECU 10 of the driving assistance device 100 determines whether or not a deceleration target has been detected by the deceleration target detection unit 11 in S10. The deceleration target detection unit 11 detects a deceleration target in front of the host vehicle based on the detection result of the external sensor 1. If it is determined that a deceleration target has been detected (S10: YES), the driving assistance ECU 10 proceeds to S12. If it is determined that a deceleration target has not been detected (S10: NO), the driving assistance ECU 10 ends the current deceleration assistance start process. After that, the driving assistance ECU 10 repeats the process from S10 again after a predetermined time has elapsed.

[0050] In S12, the driving assistance ECU 10 recognizes the relative situation between the host vehicle and the deceleration target by the relative situation recognition unit 12. The relative situation recognition unit 12 recognizes the relative situation between the host vehicle and the deceleration target based on the detection result of the external sensor 1, for example.

[0051] In S14, the driving assistance ECU 10 determines whether the deceleration assistance preconditions for the deceleration target are satisfied by the start condition determination unit 13. The start condition determination unit 13 determines whether the deceleration assistance preconditions are satisfied based on the relative situation between the host vehicle and the deceleration target. If the driving assistance ECU 10 determines that the deceleration assistance preconditions are satisfied (S14: YES), the driving assistance ECU 10 proceeds to S16. If the driving assistance ECU 10 does not determine that the deceleration assistance preconditions are satisfied (S14: NO), the driving assistance ECU 10 ends the current deceleration assistance start process. After that, the driving assistance ECU 10 repeats the process from S10 again after a predetermined time has elapsed.

[0052] In S16, the driving assistance ECU 10 determines whether the driver is not operating the accelerator or the brake by the deceleration assistance execution unit 14. "No accelerator or brake operation" means that neither the accelerator nor the brake is being operated. The deceleration assistance execution unit 14 makes the above determination based on the accelerator operation signal of the accelerator pedal sensor 3 and the brake operation signal of the brake pedal sensor 4.

[0053] When the driving assistance ECU 10 determines that the driver is not operating the accelerator and the brakes (S16: YES), the driving assistance ECU 10 proceeds to S18. When the driving assistance ECU 10 determines that the driver is operating the accelerator or the brakes (S16: NO), the driving assistance ECU 10 proceeds to S20.

[0054] In S18, the driving assistance ECU 10 executes deceleration assistance for the deceleration target by the deceleration assistance execution unit 14. The deceleration assistance execution unit 14 executes deceleration assistance by transmitting a control signal to the actuator 5. Thereafter, the driving assistance ECU 10 ends the current deceleration assistance start process.

[0055] In S20, the driving assistance ECU 10 judges whether or not the driver released the brakes while the deceleration assistance preconditions are satisfied by the start condition judgment unit 13. If it is judged that the driver released the brakes (S20: YES), the driving assistance ECU 10 proceeds to S22. If it is not judged that the driver released the brakes (S20: NO), the driving assistance ECU 10 ends the current deceleration assistance start process. After that, the driving assistance ECU 10 repeats the process from S10 again after a predetermined time has elapsed.

[0056] In S22, the driving assistance ECU 10 prohibits the deceleration assistance execution unit 14 from performing deceleration assistance for a certain period of time. The deceleration assistance execution unit 14 does not perform deceleration assistance until a certain period of time has elapsed since the brace release, even if the deceleration assistance preconditions are satisfied and no accelerator operation or brake operation is performed. The driving assistance ECU 10 repeats the process from S10 again after the above-mentioned certain period of time has elapsed. Alternatively, when the driving assistance ECU 10 repeats the process from S10, it does not start deceleration assistance until the above-mentioned certain period of time has elapsed, even if the deceleration assistance preconditions are satisfied and no accelerator operation or brake operation is performed.

[0057] According to the driving assistance device 100 of this embodiment described above, in cases where it is determined that the deceleration assistance preconditions are met but deceleration assistance cannot be started because the driver is braking, deceleration assistance is not executed until a certain time has elapsed since the brakes were released. This prevents the driver from feeling uncomfortable when deceleration assistance is executed immediately despite the driver having determined that deceleration is not necessary and having released the brakes.

[0058] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment. The present invention can be embodied in various forms including the above-mentioned embodiment and various modifications and improvements based on the knowledge of those skilled in the art. [Explanation of symbols]

[0059] 1...external sensor, 2...internal sensor, 3...accelerator pedal sensor, 4...brake pedal sensor, 5...actuator, 10...driving assistance ECU, 11...deceleration target detection unit, 12...relative situation recognition unit, 13...start condition determination unit, 14...deceleration assistance execution unit, 100...driving assistance device.

Claims

[Claim 1] A driving assistance device that assists in deceleration of a vehicle, a deceleration object detection unit that detects a deceleration object in front of the host vehicle based on a detection result of an external sensor of the host vehicle; a relative situation recognition unit that recognizes a relative situation between the deceleration target and the host vehicle based on a detection result of an external sensor of the host vehicle; a deceleration support execution unit that performs deceleration support for the host vehicle when a relative situation between the deceleration target and the host vehicle satisfies a predefined deceleration support precondition and when a driver of the host vehicle is not performing an accelerator operation or a brake operation; Equipped with the deceleration support execution unit, when the deceleration support prerequisite is satisfied but the deceleration support is not started because the brake operation is being performed, does not execute the deceleration support until a certain time has elapsed since the brake was released, The certain period of time is set to a different value depending on the type of the deceleration target, The types of deceleration targets include a curve, a car, a bicycle, and a pedestrian, The certain time is set to be shorter when the deceleration target is the automobile than when the deceleration target is the curve, The certain time is set to be shorter when the deceleration target is the bicycle or the pedestrian than when the deceleration target is the automobile, A driving assistance device, wherein the certain period of time is set to be shorter as the vehicle speed of the host vehicle is higher.

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