JP2012128612A - Driving support method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving support method for displaying driving support information according to road information and traffic jam prediction obtained by acceleration of an own vehicle.SOLUTION: The driving support method includes the steps of: detecting acceleration of an own vehicle; calculating a power spectrum corresponding to frequency by frequency analysis of the detected acceleration; calculating a maximum value of tilt variation in a simple regression line of the calculated power spectrum; calculating the degree of traffic jam prediction at the front of the own vehicle corresponding to the tilt maximum value; extracting positions of uphill and downhill slopes and positions of clothoid sections from a road map database; creating driving support information from the tilt maximum value and the two positions; and displaying the driving support information. In the step of creating the driving support information, the driving support information is created when the clothoid section is present at the uphill or downhill slope and it is determined that there is the traffic jam prediction by the degree of the traffic jam prediction.

Description

  The present invention relates to a driving support method, and more specifically to a driving support method for displaying driving support information according to road information and a traffic jam sign obtained from the acceleration of the host vehicle.

  Conventionally, a traffic jam is more likely to occur on an uphill or sag portion (concave portion) of a road than on a flat road. For this reason, on the uphill or sag portion, various displays are performed on the information display board provided on the road in order to alert the driver and prevent or alleviate traffic congestion.

  Patent Document 1 describes a recommended vehicle speed setting device or a vehicle control device that sets a recommended vehicle speed based on corner information of a road ahead in the traveling direction.

JP 2006-331000 A

  However, the conventional method of using an information display board is not necessarily installed in a required place from the viewpoint of the installation position of the information display board and its cost, and the effect is sufficiently exhibited. There is no situation.

  Further, in the method described in Patent Document 1, the recommended vehicle speed is set based only on the corner information without considering any traffic jam information, which is sufficient to actually prevent or reduce the traffic jam. It can not be said.

  Therefore, an object of the present invention is to provide a driving support method that enables a driver to appropriately and quickly perform a driving operation for actually avoiding or mitigating traffic jam on an uphill or sag portion of a road where traffic jam is likely to occur. Is to provide.

  The present invention includes a step of detecting an acceleration of the host vehicle, a step of calculating a power spectrum corresponding to the frequency from a frequency analysis of the detected acceleration, a single regression line of the calculated power spectrum is calculated, and a predetermined frequency range is calculated. The step of calculating the maximum value of the amount of change in the slope of the single regression line as the maximum value of the slope, the step of calculating the sign of congestion in front of the host vehicle according to the maximum value of the tilt, and the host vehicle proceeding from the road map database The step of extracting the uphill or downhill position and the position of the clothoid section, the step of creating the driving support information from the traffic jam sign level and the two positions, and the driving support information are displayed. The step of creating driving support information is whether there is a clothoid section on an uphill or downhill and whether it is a sign of congestion If it is determined that there is traffic congestion indication, to create a driving support information is driving support method.

  According to the present invention, in the uphill or downhill clothoid section, the driver can visually grasp the driving support information, so that the driver can quickly shift to a driving operation for avoiding or mitigating traffic jams. It becomes possible.

  According to an aspect of the present invention, the step of creating the driving support information includes generating the driving support information for narrowing the inter-vehicle distance with the preceding vehicle and, when there is a clothoid section going uphill, a clothoid going downhill If there is a section, driving support information that slowly decelerates is created.

  According to one aspect of the present invention, it is possible to prevent the vehicle speed from falling in the uphill clothoid section and increase the inter-vehicle distance, and to increase the vehicle speed in the downhill clothoid section and to reduce the inter-vehicle distance. It becomes possible to prevent.

According to one aspect of the present invention, the step of displaying the driving support information changes the display form between displaying the driving support information for narrowing the distance to the vehicle ahead and displaying the driving support information for slowly decelerating. According to one aspect of the present invention, it is possible to instantly grasp whether the inter-vehicle distance to the preceding vehicle should be increased or decreased, and it is possible to quickly shift to a driving operation for that purpose.

It is a figure which shows the structure of the apparatus which implements the driving assistance method according to one Example of this invention. FIG. 4 shows an acceleration spectrum according to one embodiment of the present invention. It is a figure for demonstrating the relationship between the traffic jam sign degree and inclination maximum value according to one Example of this invention. It is the figure which illustrated the clothoid area. It is a figure which shows the example of arrangement | positioning of a display device according to one Example of this invention. It is a figure which shows the example of a display by a display according to one Example of this invention. It is a flowchart of driving assistance control according to one example of the present invention.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a driving support apparatus 10 that performs a driving support method according to an embodiment of the present invention. The driving support device 10 is mounted on a vehicle. The driving support device 10 can be mounted on a vehicle as one device or as a part of another device.

  The driving support device 10 includes a vehicle speed sensor 11, a radar device 12, a navigation device 13, a processing device 14, a switch 15, various actuators 16, a speaker 17, a display 18, a communication device 19, and a map database (DB) 20. Composed. Note that the processing device 14 may be incorporated in the navigation device 13. In addition, the speaker 17 and the display 18 may use corresponding functions provided in the navigation device 13. Furthermore, the map DB 20 does not have to be part of the driving support device 10, and it is sufficient that the navigation device 13 can download the road map data via the network using a mobile phone network or a wireless LAN.

  The vehicle speed sensor 11 detects the acceleration of the host vehicle and sends a detection signal to the processing device 14. The radar device 12 divides a predetermined detection target region set around the host vehicle into a plurality of angle regions, and transmits an electromagnetic wave such as an infrared laser or millimeter wave while scanning each angle region. . The radar device 12 receives a reflection signal (electromagnetic wave) from an object in the detection target region and sends the reflection signal to the processing device 14.

  The navigation device 13 receives a positioning signal such as a GPS signal and calculates the current position of the host vehicle from the positioning signal. The navigation device 13 can also calculate the current position of the host vehicle from the acceleration and yaw rate detected by the vehicle speed sensor 11 and the yaw rate sensor (not shown) using autonomous navigation. The navigation device 13 has a function of outputting the current position of the host vehicle, route information to a destination, traffic jam information, and the like on a map to be displayed.

  The processing device 14 includes a frequency analysis unit 31, a single regression line calculation unit 32, a slope maximum value calculation unit 33, a reflection point detection unit 34, another vehicle detection unit 35, an inter-vehicle distance detection unit 36, a traffic jam sign degree calculation unit 37, and a clothoid. The information extraction part 38, the driving assistance information creation part 39, the communication control part 40, the alerting | reporting control part 41, and the traveling control part 42 are provided. The function of each block is realized by a computer (CPU) included in the processing device 14. Details of the function of each block will be described later.

  The processing device 14 has, for example, an A / D conversion circuit that converts an input analog signal into a digital signal, a central processing unit (CPU) that performs various arithmetic processing, and a CPU that stores data when performing arithmetic operations. It includes a RAM to be used, a ROM for storing programs to be executed by the CPU and data to be used (including tables and maps), an output circuit for outputting a drive signal for the speaker 17, a display signal for the display 18, and the like.

  The switch 15 outputs various signals related to traveling control of the host vehicle to the processing device 14. The various signals include, for example, accelerator pedal and brake pedal operation (position) signals, various signals related to automatic travel control (ACC) (control start, control stop, target vehicle speed, inter-vehicle distance, and the like).

  The various actuators 16 are used as a general term for a plurality of actuators, and include, for example, a throttle actuator, a brake actuator, a steering actuator, and the like.

  The display 18 includes a display such as an LCD, and can be a display having a touch panel function. The display 18 may be configured to include an audio output unit and an audio input unit. In response to a control signal from the notification control unit 41, the display device 18 notifies the driver by displaying predetermined alarm information or blinking or lighting a predetermined warning lamp. The speaker 17 notifies the driver by outputting a predetermined warning sound or sound according to a control signal from the notification control unit 41.

  The communication device 19 communicates with another vehicle or a server device (not shown) or a relay station (not shown) by wireless communication under the control of the communication control unit 40, and receives traffic jam information and the like from the other vehicle. The acquired information is sent to the notification control unit 41 or the travel control unit 42 via the communication control unit 40.

  Next, the function of each block of the processing device 14 will be described. The frequency analysis unit 31 performs frequency analysis on the acceleration of the host vehicle detected by the vehicle speed sensor 11 and calculates a power spectrum. FIG. 2 shows examples of power spectra in two different traveling states (a) and (b). In FIG. 2, acceleration spectra 51 and 53 corresponding to frequencies are illustrated as power spectra.

  The single regression line calculation unit 32 performs a single regression analysis on the obtained power spectrum and calculates a single regression line. In the example of FIG. 2, the straight lines indicated by reference numerals 52 and 54 are simple regression lines obtained for the acceleration spectra 51 and 53, respectively.

  The slope maximum value calculation unit 33 calculates the slope maximum value from the obtained single regression line. In the example of FIG. 2, first, the slopes of the single regression lines 52 and 54 are calculated. That is, in FIG. 2, the slope α (= Y / X) based on the change X of the spectral value in a predetermined frequency range Y (for example, a frequency range corresponding to a time range of several seconds to several minutes, 0 to 0.5 Hz, etc.). ) Is calculated. In FIG. 2, the inclinations α1 and α2 at (a) and (b) are obtained.

Next, a difference between the obtained inclinations α, that is, a difference Δα (= α _k −α _k−1 ) between the inclinations α _k and α _k−1 at a predetermined time interval is calculated. The maximum value of the time change of the obtained difference Δα or the time change of the parameter (for example, absolute value | Δα |, square value (Δα) ^2, etc.) obtained from the difference Δα is obtained. The obtained maximum value is stored in a memory (RAM or the like) in the processing device 14 as a tilt maximum value.

  The traffic jam sign calculator 37 calculates the traffic jam sign degree according to the slope maximum value calculated by the slope maximum value calculator 33. Here, the traffic jam sign is defined as a parameter indicating the possibility of traffic jam on the road (lane) ahead of the host vehicle. In other words, the traffic jam predictor increases when the possibility of traffic jam is high, and decreases when the possibility is low. In the present invention, this traffic jam sign degree is calculated from the slope maximum value.

  FIG. 3 is a diagram for explaining the relationship between a traffic jam sign and a slope maximum value. The straight lines 56 and 57 in FIG. 3 are single regression lines obtained by the single regression line calculation unit 32 in the same manner as the straight lines 52 and 54 in FIG. The single regression line 56 is an example when the slope α is small, and the single regression line 57 is an example when the slope α is large. An arbitrary value can be set as the threshold value for determining the magnitude of the traffic jam sign degree, but “−45 degrees”, which is generally known as (1 / f) fluctuation characteristics, can be set as the value. .

  The case where the inclination α is small corresponds to a case where the shock wave (vibration, fluctuation) received from the preceding vehicle is small, and corresponds to the case where the distance between the vehicles becomes short and the vehicle group becomes dense, that is, there is a high possibility of congestion. In this case, the sign of congestion is a large value. Conversely, a large slope α corresponds to a case where the shock wave (vibration, fluctuation) received from the preceding vehicle is large, and corresponds to a case where the vehicle group tends to become dense, that is, there is a high possibility of a traffic jam. In this case, the sign of congestion is a large value. The shock wave (vibration, fluctuation) referred to here means that each vehicle repeats acceleration and deceleration operations to propagate the operation (back and forth movement) as a kind of vibration to the rear vehicle. In the example of FIG. 3, as the inclination α increases from the single regression line 56 toward the single regression line 57, the possibility of traffic jams increases, that is, the traffic jam sign rate increases.

Accordingly, in the present invention, the magnitude of the slope of this single regression line, more specifically, the slope maximum value calculated by the slope maximum value calculation unit 33 (for example, | Δα |, (Δα) ^2, etc.) The traffic congestion sign is calculated according to the maximum value. For example, for example, a function (for example, y = ax + b) indicating the relationship between the slope maximum value (x) and the traffic jam sign degree (y) is obtained in advance, and the slope maximum value (x ) To calculate the traffic sign (y). Alternatively, the relationship between the maximum value of the slope and the corresponding traffic jam sign value is created in advance and stored in a memory as a table, and the traffic jam sign level for the calculated slope maximum value can be obtained by referring to the table. it can.

  The traffic jam sign calculation unit 37 sends a control signal including the calculated traffic jam sign degree to the driving support information creation unit 39, and further to the communication control unit 40, the notification control unit 41, and the travel control unit 42. Further, the traffic jam sign calculating unit 37 outputs the traffic jam sign degree to the navigation device 13. The navigation device 13 determines the route of the host vehicle so as to avoid the traffic jam based on the traffic jam sign degree received from the traffic jam sign calculation unit 37 and the traffic jam prediction result predicted by the other vehicle output from the communication control unit 40. Search and route guidance can be performed.

  The reflection point detector 34 detects the position of the reflection point (object) from the reflection signal detected by the radar apparatus 12. The other vehicle detection unit 35 is based on the position information of the reflection point output from the reflection point detection unit 34, and is at least one or more units present in the vicinity of the host vehicle from the distance between adjacent reflection points, the distribution state of the reflection points, and the like. Detect other vehicles. The inter-vehicle distance detection unit 36 detects the inter-vehicle distance between the host vehicle and the other vehicle from the other vehicle information detected by the reflection point detection unit 34, and uses the result as a communication control unit 40, a notification control unit 41, and a travel control. To the unit 42.

  The clothoid information extraction unit 38 extracts, from the road map information acquired from the map DB 20 via the navigation device 13, the position of the uphill or the downhill and the position of the clothoid section on the road on which the host vehicle travels. At that time, it is determined whether or not a clothoid section exists in the vicinity of the uphill or downhill position, and if it exists, the position of the uphill or downhill and the position of the clothoid section are set as a set of information ( Data) is stored in the memory and sent to the driving support information creation unit 39 at the same time.

  The clothoid section is also called a clothoid curve and means a road section where a relaxation curve is formed. FIG. 4 is a diagram illustrating a clothoid section. On the road 45, the sections indicated by the symbols C1 to C4 in order from the current position toward the traveling direction are clothoid sections. In the embodiment of the present invention, when there is an uphill or downhill, the position (section) information of each clothoid section from C1 to C4 is associated with the information of the uphill or downhill position (section) and stored in the memory. At the same time, it is sent to the driving support information creation unit 39.

  The driving support information creation unit 39 has an uphill or downhill ahead of the road on which the vehicle travels, a clothoid section exists on the uphill or downhill, and a traffic jam sign is calculated from the calculated traffic jam sign level. If it is determined that there is, driving support information is created. Specifically, for example, when there is a clothoid segment going uphill and there is a traffic jam sign, driving support information for narrowing the distance to the vehicle ahead is created. In addition, when there is a clothoid section heading downhill and there is a traffic jam sign, driving support information that slowly decelerates is created. The driving support information is merely an example, and other parameters (speed, acceleration / deceleration, etc.) may be included in the driving support information. In the case of a downhill, use of an engine brake is recommended from the viewpoint of safety and fuel consumption, and therefore driving support information may be provided so as to slowly decelerate using the engine brake. The driving support information creation unit 39 sends the created driving support information to the notification control unit 41.

  The notification control unit 41 sends a notification control signal to the display 18 and the speaker 17 in order to notify the driving support information output from the driving support information creation unit 39. When using the voice, the notification control unit 43, for example, “Decelerate gently”, “Decelerate slowly using the engine brake”, “Narrow the distance to the vehicle ahead. Please send a control signal for transmitting voice from the speaker 17 such as “Please increase the speed and reduce the distance between the vehicles”. When using the display by the display 18, the following display is performed, for example. Note that the notification by voice and display may be either one of them or a combination of both.

  FIG. 5 is a diagram showing an example of the arrangement of the indicator in the passenger compartment according to one embodiment of the present invention. In FIG. 5, the case where the display part 63 is installed in the lower part of the room mirror 62 located on the centerline C of a vehicle interior, and the case where it installs on the front cover part 60 are illustrated. The display unit 63 may be incorporated as a part of the display unit 61 of the navigation device 13 or may be disposed on the top thereof. The display unit 63 is preferably located near the center of the passenger compartment. The reason is that the display unit 63 is positioned near the center of the passenger compartment, so that the display unit 63 can be placed in the driver's field of view regardless of whether the driver's line of sight is directed to the left or right. .

  FIG. 6 is a diagram illustrating a display example of the display unit 63. The display unit 63 includes lighting units 631 and 632 that display that the vehicle is slowly decelerated or the inter-vehicle distance is reduced. The lighting unit 631 is lit or blinks in a predetermined color (for example, green) when gradually decelerating and widening the inter-vehicle distance, that is, for example, when there is a clothoid section heading downhill and there is a traffic jam sign. The lighting unit 632 lights or blinks in a predetermined color (for example, red) when the inter-vehicle distance is narrowed, that is, for example, when there is a clothoid section heading uphill and there is a traffic jam sign. In addition, the character display in the lighting parts 631 and 632 in the figure is described for explanation, and may or may not be actually displayed. With this display, the driver can grasp the possibility of traffic congestion in the clothoid section ahead, and at the same time, in order to avoid traffic congestion, gently slow down to increase the inter-vehicle distance or increase the speed to increase the inter-vehicle distance. By narrowing and allowing the vehicle to follow the vehicle ahead, the maximum acceleration spectrum is suppressed.

  The display block 634 displays the inter-vehicle distance (m) sent from the inter-vehicle distance detection unit 36. The display blocks 635, 636, and 637 are switch buttons, which are a switch that turns off the display of the lighting units 631 and 632, a switch that turns off the display of the display block 634, and a switch that turns off the display of the entire display unit 63, respectively. . The driver can manually stop the corresponding display function by pressing (touching) each switch.

  The travel control unit 42 includes a traffic jam sign level output from the traffic jam sign calculation unit 37, a traffic jam occurrence prediction result predicted in another vehicle output from the communication control unit 40, and various signals output from the switch 15. The travel of the host vehicle is controlled by controlling various actuators based on the detection result of the acceleration of the host vehicle output from the vehicle speed sensor 11 and the detection result of the inter-vehicle distance output from the inter-vehicle distance detection unit 36. That is, for example, the traveling control unit 42 starts or stops execution of automatic traveling control (ACC) according to a signal output from the switch 15, and sets or changes the target vehicle speed and the target inter-vehicle distance in ACC.

  FIG. 7 is a flowchart of the driving support control according to one embodiment of the present invention. The details of each step are as described above. In step S10, the vehicle speed sensor 11 detects the acceleration of the host vehicle. In parallel, in step S12, an inter-vehicle distance from a vehicle around the host vehicle is detected based on an output signal from the radar device 12 (blocks 34 to 36 in FIG. 1).

  In step S14, a single regression maximum of the acceleration spectrum is performed. More specifically, the above-described inclination maximum value is calculated (blocks 31 to 33 in FIG. 1). In step S16, a traffic jam sign is calculated (block 37 in FIG. 1). In step S18, it is determined whether there is a traffic jam sign, that is, whether the traffic jam sign degree is greater than a predetermined value. If this determination is No, the process returns to step S14 and the subsequent flow is repeated. If the determination in step S18 is Yes, road information is acquired in the next step S20.

  In step S22, the position of the uphill or downhill and the position of the clothoid section on the road on which the host vehicle travels are extracted from the road information (block 38 in FIG. 1). In step S24, it is determined whether it is a clothoid section on a downhill. When this determination is Yes, in the next step S26, a display that slowly decelerates (for example, lighting of 631 in FIG. 6) is displayed. If the determination in step S24 is No, it is determined in step S28 whether or not it is an uphill and a clothoid segment. When this determination is Yes, in the next step S30, a display for narrowing the inter-vehicle distance (for example, lighting of 632 in FIG. 6) is performed. When the determination in step S28 is No, in step S32, the display of driving assistance is turned off (for example, 631 and 632 in FIG. 6 are turned off).

  Thus, according to the embodiment of the present invention, on the premise that a clothoid segment is extracted from map information, the state transition due to the spectrum maximum in the clothoid segment is monitored to determine whether there is a traffic jam sign, and the result is By notifying the driver, it is possible to efficiently eliminate the vehicle group and promote avoidance or mitigation of traffic congestion.

  The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and can be modified and used without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Driving assistance apparatus 14 Processing apparatus 45 Road 51, 53 Acceleration (power) spectrum 52, 54, 56, 57 Single regression line 63 Display part

Claims (3)

Detecting the acceleration of the host vehicle;
Calculating a power spectrum corresponding to the frequency from frequency analysis of the detected acceleration;
Calculating a single regression line of the calculated power spectrum, and calculating a maximum value of a change amount of the slope of the single regression line in a predetermined frequency range as a slope maximum value;
Calculating a traffic jam sign in front of the host vehicle according to the slope maximum value;
Extracting an uphill or downhill position and a clothoid section position on a road on which the vehicle travels from a road map database;
Creating driving support information from the traffic sign and the two positions;
Displaying the driving support information, and
The step of creating the driving support information includes generating driving support information when the clothoid segment exists on the uphill or downhill and it is determined that there is a traffic jam sign from the traffic jam sign degree. Method.   In the step of creating the driving support information, when the clothoid section heading for the uphill exists, the driving support information for narrowing the distance to the vehicle ahead is created, and the clothoid section heading for the downhill exists. The driving support method according to claim 1, wherein in the case, driving support information that slowly decelerates is created.   The step of displaying the driving support information changes a display form between the case of displaying driving support information that narrows the distance to the vehicle ahead and the case of displaying driving support information that slowly decelerates. Driving support method.

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