JP7848830B2 - Driving assistance systems - Google Patents

Description

This invention relates to a driver assistance device.

Conventionally, Japanese Patent Publication No. 2013-218429 is known as a technical document concerning driver assistance systems. This publication describes a driver assistance system that assists in decelerating a vehicle when it is predicted to stop at a predetermined stopping position. It describes a system that provides deceleration assistance (deceleration control) when the distance to the stopping position and the vehicle speed do not meet predetermined conditions, and does not provide deceleration assistance when the predetermined conditions are met.

Japanese Patent Publication No. 2013-218429

Incidentally, in deceleration assistance systems that slow down a vehicle, it is desirable that the transition from the end of deceleration assistance to the driver's operation (such as accelerator operation) be smooth. In this regard, with the conventional driver assistance systems mentioned above, the driver does not know how far the deceleration assistance will continue, which could cause anxiety in the driver or lead to overconfidence in the deceleration assistance.

One aspect of the present invention is a driver assistance device that performs deceleration assistance for a vehicle when a deceleration target is detected in front of the vehicle, the deceleration target includes traffic lights, stop lines, or stop signs, and deceleration assistance is started for the deceleration target when the relative situation between the vehicle and the deceleration target satisfies the deceleration assistance start conditions, the deceleration assistance start conditions are changed according to the type of deceleration target, and during the execution of deceleration assistance, information regarding the position where the vehicle is scheduled to stop due to the deceleration assistance is displayed on the vehicle's display, and the information regarding the position where the vehicle is scheduled to stop is set according to the type of deceleration target.

According to one aspect of the present invention, information regarding the position where the vehicle is scheduled to stop due to deceleration assistance can be displayed on the vehicle's display .

A block diagram showing a driver assistance device according to one embodiment. (a) A diagram showing an example of how the termination timing notification is displayed. (b) A diagram showing another example of how the termination timing notification is displayed. (c) A diagram showing yet another example of how the termination timing notification is displayed. (a) A flowchart showing an example of the deceleration support start process. (b) A flowchart showing an example of the deceleration support end timing notification process. (c) A flowchart showing an example of the deceleration support end process.

The embodiments of the present invention will be described below with reference to the drawings.

As shown in Figure 1, the driver assistance device 100 is installed in a vehicle such as a passenger car (the vehicle itself) and is a device that assists the driver in operating the vehicle. When the driver assistance device 100 detects a preceding vehicle or a traffic light or other object that will cause deceleration in front of the vehicle, it provides deceleration assistance for the vehicle under predetermined conditions.

A "deceleration target" refers to anything that triggers deceleration assistance. This includes preceding vehicles, traffic lights, stop signs, and stop lines. In addition to preceding vehicles, pedestrians, cyclists, curves, crosswalks, fallen objects, construction equipment, and structures may also be included as deceleration targets.

Deceleration assistance is a driving assistance system that slows the vehicle down to a pre-set target speed. The target speed is not particularly limited; it may be 0 km/h or 10 km/h. The target speed may also be determined according to the type of object being decelerated. If the object being decelerated is a traffic light, the target speed for deceleration assistance may be changed according to the traffic light's illumination status (green, yellow, red, etc.). If the object being decelerated is a moving object such as a preceding vehicle, the target speed is not limited to the vehicle's speed; the relative speed between the vehicle and the object being decelerated may be used.

[Configuration of driver assistance systems]
The configuration of a driver assistance device 100 according to one embodiment will be described with reference to the drawings. As shown in Figure 1, the driver assistance device 100 includes a driver assistance ECU (Electronic Control Unit) 10 that comprehensively manages the device. The driver assistance ECU 10 is an electronic control unit having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. The driver assistance ECU 10 realizes various functions, for example, by loading a program stored in ROM into RAM and executing the program loaded into RAM with the CPU. The driver assistance ECU 10 may be composed of a plurality of electronic units.

The driver assistance ECU 10 is connected to the external sensor 1, the internal sensor 2, the HMI (Human Machine Interface) 3, and the actuator 4.

External sensor 1 is a detection device that detects the surrounding conditions of the vehicle. External sensor 1 includes at least one of a camera and a radar sensor. The camera is an imaging device that captures images of the external conditions of the vehicle. The camera is, for example, mounted on the back of the vehicle's windshield and captures images of the area in front of the vehicle. The camera transmits the image information regarding the external conditions of the vehicle to the driver assistance ECU 10. The camera may be a monocular camera or a stereo camera.

A radar sensor is a detection device that uses radio waves (e.g., millimeter waves) or light to detect objects around a vehicle. Examples of radar sensors include millimeter-wave radar and LiDAR (Light Detection and Ranging). The radar sensor detects objects by transmitting radio waves or light around the vehicle and receiving the radio waves or light reflected by the object. The radar sensor transmits information about the detected object to the driver assistance ECU 10. Objects include fixed obstacles such as guardrails and buildings, as well as moving obstacles such as pedestrians, bicycles, and other vehicles.

The internal sensor 2 is a detection device that detects the driving state of the 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 vehicle. For example, a wheel speed sensor is used, which is mounted on the vehicle's wheels or a drive shaft rotating integrally with the wheels, and detects the rotational speed of the wheels. The vehicle speed sensor transmits the detected vehicle speed information (wheel speed information) to the driver assistance ECU 10.

An acceleration sensor is a detector that detects the acceleration of the vehicle. The acceleration sensor includes, for example, a longitudinal acceleration sensor that detects the vehicle's acceleration in the longitudinal direction, and a lateral acceleration sensor that detects the vehicle's lateral acceleration. The acceleration sensor transmits, for example, the vehicle's acceleration information to the driver assistance ECU 10. A yaw rate sensor is a detector that detects the yaw rate (rotational angular velocity) of the vehicle around the vertical axis of its center of gravity. For example, a gyroscope sensor can be used as the yaw rate sensor. The yaw rate sensor transmits the detected vehicle's yaw rate information to the driver assistance ECU 10.

HMI3 is an interface for inputting and outputting information between the driver assistance system 100 and the driver. HMI3 includes, for example, a display and speakers. HMI3 outputs images to the display and audio to the speakers in response to control signals from the driver assistance ECU 10. The display may be a HUD (Head-Up Display). The display may also be a MID (Multi-Information Display) located on the instrument panel.

Actuator 4 is a device used for controlling the vehicle. Actuator 4 includes at least a drive actuator and a brake actuator. Actuator 4 may also 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 driver assistance ECU 10, thereby controlling the vehicle's driving force. If the vehicle is a hybrid vehicle, in addition to the amount of air supplied to the engine, a control signal from the driver assistance ECU 10 is input to the motor, which serves as a power source, to control its driving force. If the vehicle is an electric vehicle, a control signal from the driver assistance ECU 10 is input to the motor, which serves as a power source, to control its driving force. In these cases, the motor, which serves as a power source, constitutes actuator 4.

The brake actuator controls the brake system in response to control signals from the driver assistance ECU 10, and controls the braking force applied to the vehicle's wheels. For example, a hydraulic brake system can be used as the brake system. The steering actuator controls the drive of the assist motor that controls the steering torque within the electric power steering system in response to control signals from the driver assistance ECU 10. In this way, the steering actuator controls the steering torque of the vehicle.

Next, the functional configuration of the driver assistance ECU 10 will be described. As shown in Figure 1, the driver assistance ECU 10 includes a deceleration target recognition unit 11, a relative situation recognition unit 12, a start condition determination unit 13, a driver assistance unit 14, an end timing estimation unit 15, and a notification unit 16. Note that some of the functions of the driver assistance ECU 10 described below may be executed on a server capable of communicating with the vehicle.

The deceleration target recognition unit 11 recognizes the deceleration target in front of the vehicle based on the detection results of the external sensor 1. The deceleration target recognition unit 11 may also recognize the type of deceleration target (e.g., a preceding vehicle, traffic light, stop sign). The deceleration target recognition unit 11 detects and recognizes the type of deceleration target by performing pattern matching using pre-stored image patterns for each type, based on, for example, the image captured in front of the vehicle by a camera. The deceleration target recognition unit 11 may also recognize the type of deceleration target based on object information from a radar sensor.

The relative situation recognition unit 12 recognizes the relative situation between the vehicle and the object being decelerated. The relative situation includes at least the distance between the vehicle and the object being decelerated (distance in the longitudinal or forward direction of the vehicle). The relative situation may also include the relative speed between the vehicle and the object being decelerated.

The relative situation recognition unit 12 recognizes the relative situation between the vehicle and the vehicle being decelerated, for example, based on the detection results of the external sensor 1. If the vehicle being decelerated is a vehicle capable of vehicle-to-vehicle communication with the vehicle being decelerated, the relative situation recognition unit 12 may recognize the relative situation between the vehicle and the vehicle being decelerated using information obtained through vehicle-to-vehicle communication. The relative situation recognition unit 12 may also recognize the relative speed between the vehicle and the vehicle being decelerated, for example, based on the speed of the vehicle being decelerated and the speed of the vehicle being decelerated, obtained through vehicle-to-vehicle communication.

The start condition determination unit 13 determines whether the deceleration support start conditions for the vehicle to be decelerated have been met. The deceleration support start conditions are pre-set conditions used to determine the start of deceleration support. The start condition determination unit 13 determines whether the deceleration support start conditions have been met based at least on the distance between the vehicle and the vehicle to be decelerated.

The deceleration support initiation conditions may be changed depending on the type of vehicle being decelerated. For example, if the type of vehicle being decelerated is a preceding vehicle, the initiation condition determination unit 13 determines whether the deceleration support initiation conditions for the preceding vehicle have been met, based on the relative situation between the vehicle and the vehicle being decelerated (e.g., TTC).

Let's specifically explain the case where the target of deceleration is a traffic light. If the start condition determination unit 13 determines that the traffic light is not in a pass-permit state (green light), it determines whether the deceleration support start conditions for the traffic light have been met, at least based on the distance between the vehicle and the traffic light. Note that the traffic light not being in a pass-permit state may also be one of the deceleration support start conditions.

The start condition determination unit 13 determines that the deceleration support start condition has been met, for example, when the distance between the vehicle and the traffic light is less than the distance threshold. The distance threshold is a preset threshold value. Here, the position of the traffic light used to calculate the distance between the vehicle and the traffic light may be either the position of the traffic light itself or the position of the stop line before the traffic light. If the start condition determination unit 13 cannot detect the stop line before the traffic light using the external sensor 1 due to wear on the white line of the stop line, it may assume that the stop line exists at a certain distance before the traffic light and use this assumption to calculate the distance between the vehicle and the traffic light.

Furthermore, the start condition determination unit 13 may determine the deceleration support start condition using the TTC (Time To Collision) between the vehicle and the traffic light, rather than the distance between the vehicle and the traffic light. For example, the start condition determination unit 13 determines that the deceleration support start condition for the traffic light is met when the TTC between the vehicle and the traffic light is less than the TTC threshold. The TTC is calculated by dividing the distance between the vehicle and the traffic light by the vehicle's speed. The TTC threshold is a preset threshold value. The start condition determination unit 13 may also determine that the deceleration support start condition is not met if the driver is operating the accelerator pedal or brake pedal.

The driver assistance unit 14 starts deceleration assistance as driver assistance for its own vehicle when the start condition determination unit 13 determines that the deceleration assistance start conditions have been met. The driver assistance unit 14 performs deceleration assistance for its own vehicle by transmitting a control signal to the actuator 4. For example, the driver assistance unit 14 performs deceleration assistance so that the vehicle slows down to a preset target speed, based on the distance between the vehicle and the object to be decelerated and the speed of the vehicle itself.

The driving support unit 14 may, for example, provide deceleration support using a target deceleration rate. The start condition determination unit 13 calculates, for example, the target deceleration rate necessary to reduce the vehicle speed to the target speed for deceleration support before the distance between the vehicle and the object to be decelerated reaches a preset distance.

The value of the set distance is not particularly limited. The set distance may be set according to, for example, the type of object being slowed down. If the object being slowed down is a traffic light in a no-passing state (red light), the set distance may be 1m or 0.5m. If the object being slowed down is a stop sign, the set distance may be 0.5m or 0m.

The target vehicle speed for deceleration assistance may also be set according to the type of deceleration target. For example, if the type of deceleration target is a traffic light or stop sign indicating a no-passing zone, the target vehicle speed for stopping (e.g., 0 km/h) should be set. Note that the target vehicle speed for stopping does not necessarily have to be 0 km/h; it may be a value close to 0 km/h.

The driver assistance unit 14 calculates the target deceleration speed for deceleration assistance based on the relative situation between the vehicle and the object to be decelerated, and the vehicle speed of the vehicle, using the set distance and target vehicle speed mentioned above. The driver assistance unit 14 then transmits a control signal to the actuator 4 according to the target deceleration speed, thereby performing deceleration assistance for the vehicle through engine braking and/or braking.

The driver assistance unit 14 determines whether the timing for ending deceleration assistance has been reached. The timing for ending deceleration assistance is the timing at which deceleration assistance is terminated. The timing for ending deceleration assistance will be described later. The driver assistance unit 14 determines whether the termination timing has been reached based, for example, on at least one of the relative situation between the vehicle and the vehicle being decelerated, and the vehicle speed of the vehicle being decelerated. If the driver assistance unit 14 determines that the timing for ending deceleration assistance has been reached, it terminates the deceleration assistance for the vehicle being decelerated.

Furthermore, the driver assistance unit 14 terminates deceleration assistance if the driver cancels the deceleration assistance while it is being performed. Cancellation of deceleration assistance includes, for example, turning off the driver assistance function, operating the accelerator pedal or steering wheel beyond a certain amount, or performing other actions beyond a certain amount.

The termination timing estimation unit 15 estimates the termination timing of deceleration support while it is being performed. The termination timing estimation unit 15 estimates the termination timing of deceleration support based, for example, on at least one of the relative conditions between the vehicle and the vehicle being decelerated, and the vehicle speed of the vehicle itself.

The timing of the end of deceleration assistance may be indicated as the remaining time until the end of deceleration assistance, the remaining distance until the end of deceleration assistance, the distance from the end of deceleration assistance to the end of deceleration assistance, or the difference between the vehicle's current speed and the target speed for deceleration assistance (remaining deceleration amount).

The remaining time may be the time it takes for the vehicle's speed to reach the target speed for deceleration assistance, or the time it takes for the distance between the vehicle and the object being decelerated to reach the set distance. The remaining distance traveled may be the distance traveled until the vehicle's speed reaches the target speed for deceleration assistance, or the distance traveled until the distance between the vehicle and the object being decelerated reaches the set distance. The remaining deceleration amount is the difference between the vehicle's current speed and the target speed for deceleration assistance.

The notification unit 16 provides notifications regarding driving assistance to the driver of the vehicle. The notification unit 16 transmits a control signal to the HMI 3, thereby providing notifications that include at least one of the following: image output from the display and audio output from the speaker.

The notification unit 16 notifies the driver of the estimated end time of the deceleration support, as determined by the end time estimation unit 15, while deceleration support is being performed. The notification unit 16 provides notification via image display and/or sound output using the HMI 3. The notification unit 16 may also provide notification by displaying an image and/or text on the display.

Figure 2(a) shows an example of a display for the completion timing notification. The text display T shown in Figure 2(a) indicates the remaining time until the deceleration assistance ends. The text display T may be displayed on the MID, on a display mounted on the dashboard, or projected onto the vehicle's windshield. The notification unit 16 may display the text display T and also notify the driver of the remaining time by voice at predetermined intervals.

Figure 2(b) shows another example of the display for the completion timing notification. In Figure 2(b), the position of the moving bar B within the bar display frame H indicates the remaining distance until the deceleration assistance ends. The portion that the moving bar B has passed is color-coded differently from the portion it has not passed. The number at the top of the bar display frame H indicates the remaining distance until the deceleration assistance ends at the start of the assistance. The number next to the moving bar B indicates the current remaining distance. In the display shown in Figure 2(b), the driver is notified of the remaining distance until the deceleration assistance ends by the moving bar B rising within the bar display frame H as the vehicle moves.

Figure 2(c) shows yet another example of the display of the completion timing notification. The meter icon M in Figure 2(c) shows a needle Vs corresponding to the vehicle's current speed. The arrow N along the meter icon M indicates the remaining amount of deceleration the vehicle will undergo before the deceleration assistance ends. The base end Na of the arrow N corresponds to the position of the needle Vs (the vehicle's current speed), and the tip Nb of the arrow N corresponds to the target speed for deceleration assistance. In the display shown in Figure 2(c), the length of the arrow N notifies the driver of the remaining amount of deceleration until the end of deceleration assistance. In the display shown in Figure 2(c), as the vehicle decelerates, the position of the needle Vs changes counterclockwise, and the arrow N shortens (the base end Na of the arrow N approaches the tip Nb), thereby informing the driver of the change in the remaining amount of deceleration.

Furthermore, the needle Vs of the meter icon M may be fixed, while only the length of arrow N changes. Also, it is not always necessary to use an arrow; a virtual needle corresponding to the target speed for deceleration assistance could be displayed on the meter icon M, and the driver could be notified of the change in the remaining deceleration amount until the end of deceleration assistance by the needle Vs corresponding to the current vehicle speed approaching the virtual needle.

Alternatively, the driver may be notified of the remaining deceleration amount until the deceleration assistance ends by displaying an image corresponding to the arrow N above around the vehicle's speedometer. In other words, the actual vehicle's speedometer may be used instead of the meter icon M.

[Processing of driver assistance systems]
Next, the processing of the driving support device 100 of this embodiment will be described with reference to the drawings. Figure 3(a) is a flowchart showing an example of the deceleration support start process.

As shown in Figure 3(a), in the driver assistance system 100, the driver assistance ECU 10, in S10, recognizes a deceleration target in front of the vehicle using the deceleration target recognition unit 11. The deceleration target recognition unit 11 recognizes the deceleration target based on the detection results of the external sensor 1. In S10, along with the recognition of the deceleration target, the relative situation recognition unit 12 also recognizes the relative situation between the vehicle and the deceleration target.

In S12, the driver assistance ECU 10 determines, using the start condition determination unit 13, whether the deceleration support start conditions for the deceleration target have been met. The driver assistance ECU 10 determines whether the deceleration support start conditions have been met, for example, based on the distance between the vehicle and the deceleration target. If the driver assistance ECU 10 determines that the deceleration support start conditions have been met (S12: YES), it proceeds to S14. If the driver assistance ECU 10 determines that the deceleration support start conditions have not been met (S12: NO), it terminates the current process. After a certain period of time, the driver assistance ECU 10 repeats the process from S10 again.

In S14, the driver assistance ECU 10 initiates deceleration assistance for its own vehicle via the driver assistance unit 14. The driver assistance unit 14 performs deceleration assistance for the target vehicle by transmitting a control signal to the actuator 4.

Figure 3(b) is a flowchart showing an example of the deceleration support termination timing notification process. The deceleration support termination timing notification process is performed while the deceleration support is running.

As shown in Figure 3(b), the driver assistance ECU 10, in S20, estimates the termination timing of the deceleration assistance using the termination timing estimation unit 15. The termination timing estimation unit 15 estimates the termination timing of the deceleration assistance based, for example, on at least one of the relative conditions between the vehicle and the vehicle being decelerated, and the vehicle speed of the vehicle itself.

In S22, the driver assistance ECU 10 notifies the driver of the timing to end the deceleration assistance via the notification unit 16. The notification unit 16 notifies the driver of the timing to end the deceleration assistance by, for example, displaying an image as shown in Figure 2(c) on the MID, which is the display of the HMI 3. The notification unit 16 may also notify the driver of the timing to end the deceleration assistance by outputting sound.

Figure 3(c) is a flowchart showing an example of the deceleration support termination process. The deceleration support termination process is performed while deceleration support is being executed.

As shown in Figure 3(c), the driver assistance ECU 10, in step S30, determines whether the driver assistance unit 14 has reached the end of the deceleration assistance. The driver assistance unit 14 makes this determination based on, for example, the relative situation between the vehicle and the vehicle being decelerated, and at least one of the vehicle speeds of the vehicle itself. If the driver assistance ECU 10 determines that the end of the deceleration assistance has been reached (S30: YES), it proceeds to S32. If the driver assistance ECU 10 does not determine that the end of the deceleration assistance has been reached (S30: NO), it terminates the current process. After a certain period of time, the driver assistance ECU 10 repeats the process from S30 again. The current process ends. After a certain period of time, the driver assistance ECU 10 repeats the process from S10 again.

In S32, the driver assistance ECU 10 terminates the deceleration assistance via the driver assistance unit 14. The driver assistance unit 14 terminates the deceleration assistance by stopping the transmission of control signals to the actuator 4 or by transmitting a termination signal.

As described above, the driver assistance device 100 according to this embodiment estimates the timing of the end of deceleration assistance during its execution and notifies the driver of this timing. Compared to conventional cases where the driver is not notified of the end timing of deceleration assistance, this method suppresses driver anxiety and overconfidence regarding deceleration assistance. Furthermore, the driver can smoothly transition to driving operations such as accelerating their vehicle, taking into account the timing of the end of deceleration assistance.

Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above. The present invention can be implemented in various forms, starting with the embodiments described above, with various modifications and improvements based on the knowledge of those skilled in the art.

For example, the notification unit 16 may notify the driver of the timing of the end of deceleration assistance by using at least two combinations of the following: a text display as shown in Figure 2(a), a bar display as shown in Figure 2(b), or an icon display as shown in Figure 2(c).

1...External sensor, 2...Internal sensor, 3...HMI, 4...Actuator, 10...Driving support ECU, 11...Deceleration target recognition unit, 12...Relative situation recognition unit, 13...Start condition determination unit, 14...Driving support unit, 15...End timing estimation unit, 16...Notification unit, 100...Driving support device.

Claims (7)

A driver assistance device that performs deceleration assistance for the vehicle when a vehicle to be decelerated is detected in front of the vehicle,
The aforementioned objects subject to deceleration include traffic lights, stop lines, or stop signs.
When the relative situation between the vehicle itself and the object to be decelerated satisfies the conditions for initiating deceleration support, the deceleration support for the object to be decelerated is initiated.
The aforementioned deceleration support initiation conditions are changed according to the type of deceleration target,
During the execution of the deceleration assistance, information regarding the position where the vehicle is scheduled to stop due to the deceleration assistance is displayed on the vehicle's display.
The driver assistance device sets information regarding the position where the vehicle is scheduled to stop, according to the type of vehicle being decelerated. Based on the distance between the vehicle and the object to be decelerated and the speed of the vehicle, the deceleration support is performed so that the vehicle stops when the distance between the vehicle and the object to be decelerated reaches a set distance.
The driving assistance device according to claim 1, wherein the set distance is set according to the type of deceleration target. The driving assistance device according to claim 1, wherein, after initiating the deceleration assistance for the target vehicle, the device begins displaying information on the display regarding the position where the vehicle is scheduled to stop while it is being decelerated by the deceleration assistance. The driver assistance device according to claim 1, wherein, during the execution of the deceleration assistance, the device estimates the stopping timing at which the vehicle is scheduled to stop based on the vehicle's speed, and uses the estimated stopping timing to display information regarding the vehicle's planned stopping position on the display and notify the driver of the vehicle. The driving assistance device according to claim 2, wherein the position where the vehicle is scheduled to stop is the position where the distance between the vehicle and the object to be decelerated is the set distance. The driving assistance device according to claim 5 , wherein the information relating to the position where the vehicle is scheduled to stop is information relating to the remaining distance the vehicle will travel until it reaches a position where the distance between the vehicle and the deceleration target becomes the set distance. The information relating to the position where the vehicle is scheduled to stop is the remaining time until the vehicle stops, as described in claim 1.