JP2008287480A - Travel support device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To estimate a road surface state based on the traveling state of the other vehicle to reflect it in deceleration control of one's own vehicle. <P>SOLUTION: This travel support device 1 for the vehicle comprises a bidirectional radio device 5 mounted on the vehicle and capable of communicating with a base station 20 or the other vehicle Vo, and a computing section 6 performing travel support of the vehicle based on information acquired by the bidirectional radio device 5. The travel support device 1 further comprises a road information storage section 4 storing road information, a GPS receiver 2 detecting a vehicle position on a road stored in the road information storage section 4, and a traveling state detecting part 3 detecting the traveling state of the vehicle. The bidirectional radio device 5 transmits/receives vehicle position information and traveling state information to/from the base station 20 or the other vehicle Vo, and the computing section 6 estimates the road surface state in the vehicle position of the other vehicle based on the traveling state of the other vehicle acquired by the bidirectional radio device 5, and performs deceleration control of the own vehicle Vm or gives a warning to an occupant based on the estimated road surface state. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle travel support device that performs deceleration support and the like.

Predicting the occurrence of a collision based on the traveling state information of the other vehicle obtained from the traveling state of the own vehicle and the other vehicle through communication between the own vehicle and the other vehicle. In addition, when a collision is predicted, a travel support device is known that controls the travel of the host vehicle so as to reduce the impact of the collision according to the travel state of the other vehicle (see, for example, Patent Document 1). ).
JP 2007-22263 A

  By the way, not only in the case of collision avoidance, but when braking the vehicle, it is preferable to perform deceleration control according to the road surface state, and for that purpose, it is necessary to grasp the road surface state. However, the range in which the own vehicle can independently estimate the friction coefficient of the road surface (hereinafter abbreviated as road surface μ) is limited, and estimation outside the line of sight is difficult.

  Therefore, for example, even if the road surface condition of a place with poor visibility such as a curve becomes slippery, the vehicle cannot predict the road surface μ of the place, and it is difficult to perform appropriate deceleration control according to the road surface condition. There was a problem.

  Therefore, the present invention provides a vehicle travel support device that can estimate a road surface state based on travel state information of another vehicle acquired by communication and reflect it in deceleration control or the like of the host vehicle.

The vehicle travel support apparatus according to the present invention employs the following means in order to solve the above problems.
The invention according to claim 1 is a communication means mounted on a vehicle and capable of communicating with a vehicle outside information providing facility (for example, a base station 20 in an embodiment described later) or another vehicle (for example, bidirectional in an embodiment described later). A vehicle travel support device (e.g., a wireless device 5) and travel support means (e.g., a calculation unit 6 in an embodiment to be described later) that performs vehicle travel support based on information acquired by the communication unit (e.g. In a driving support apparatus 1 in an embodiment described later, a storage unit (for example, a road information storage unit 4 in an embodiment described later) for storing road information and a vehicle position on the road stored in the storage unit are detected. Position detecting means (for example, GPS receiver 2 in the embodiment described later) and traveling state detecting means for detecting the traveling state of the vehicle (for example, traveling state detection in the embodiment described later) 3), wherein the communication means transmits / receives vehicle position information and travel state information to / from the outside information providing facility or other vehicle, and the travel support means travels the other vehicle acquired by the communication means. The road surface state at the vehicle position of the other vehicle is estimated based on the state information, and deceleration control of the own vehicle or a warning to the occupant is performed based on the estimated road surface state.
By comprising in this way, the deceleration control of the own vehicle according to the road surface state of the place where the other vehicle is located, and the warning to a passenger | crew can be performed.

According to a second aspect of the present invention, in the first aspect of the invention, the running state detecting means includes a yaw rate sensor that detects a yaw rate of the vehicle, and the driving support means is a function of the other vehicle acquired by the communication means. When the moving speed of the other vehicle calculated from the vehicle position information is equal to or less than a predetermined value, and the yaw rate value of the other vehicle acquired by the communication means is equal to or greater than a first determination threshold, the other It is determined that the friction coefficient of the road surface at the vehicle position is low.
By configuring in this way, it is possible to estimate that the other vehicle is spinning since the yaw rate of the other vehicle is high even though the moving speed of the other vehicle is low, so that the other vehicle spins. It can be determined that the friction coefficient of the road surface is low.

The invention according to claim 3 is the invention according to claim 2, wherein the first determination threshold value is calculated based on a moving speed of another vehicle and road information stored in the storage means. And
Recognize the curve shape of the road from the road information stored in the storage means, calculate the yaw rate generated in an appropriate running state based on the moving speed and curve shape of the other vehicle, and use this as the first determination threshold value Thus, when the value of the yaw rate of the other vehicle is equal to or greater than the first determination threshold, it can be estimated that the other vehicle is in the spin state.

The invention according to claim 4 is the invention according to claim 1, wherein the travel support means estimates the vehicle front direction of the other vehicle based on the travel state of the other vehicle acquired by the communication means, When the estimated deviation between the vehicle front direction of the other vehicle and the road traveling direction stored in the storage means is greater than or equal to a second determination threshold value, it is determined that the friction coefficient of the road surface at the vehicle position of the other vehicle is low. It is characterized by doing.
With this configuration, when the deviation between the vehicle front direction of the other vehicle and the road traveling direction is greater than or equal to the second determination threshold, it can be estimated that the other vehicle is spinning. It can be determined that the friction coefficient of the road surface is low enough to spin.

According to a fifth aspect of the present invention, in the invention according to the fourth aspect, the travel support means increases the deviation between the estimated vehicle front direction of the other vehicle and the road traveling direction stored in the storage means. It is determined that the friction coefficient of the road surface at the vehicle position of the other vehicle is low.
By comprising in this way, the friction coefficient of a road surface can be estimated appropriately.

  According to the first aspect of the present invention, it is possible to execute deceleration control of the own vehicle and warning to the occupant according to the road surface condition of the place where the other vehicle is located. It is possible to perform the warning at the appropriate timing.

  According to the invention which concerns on Claim 2 and Claim 3, it can estimate appropriately that it is a road surface state with a low friction coefficient based on the yaw rate of another vehicle.

  According to the invention which concerns on Claim 4 and Claim 5, it can estimate appropriately that it is a road surface state with a low friction coefficient based on the deviation of the vehicle front direction of another vehicle, and a road advancing direction.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a vehicle driving support apparatus according to the present invention will be described below with reference to the drawings of FIGS.
In this embodiment, as shown in FIG. 2, for example, the host vehicle Vm travels on a straight road, a curve exists in front of the traveling direction of the straight road, and the other vehicle travels in front of the travel lane of the host vehicle Vm. Assume that a certain preceding vehicle Vo spins on a curve.

  The host vehicle Vm is provided with a driving support device 1 as shown in FIG. The travel support device 1 includes a GPS receiver (position detection means) 2, a travel state detection unit (travel state detection means) 3, a road information storage unit (storage unit) 4, a bidirectional radio (communication unit) 5, and a calculation unit. (Running support means) 6, navigation device 7, speaker (warning means) 8, brake device (braking means) 9, and seat belt (warning means) 10.

  The GPS receiver 2 corrects an error in the GPS (Global Positioning System) signal for measuring the position of the vehicle using an artificial satellite, for example, or an appropriate base station, for example, and corrects the positioning accuracy. A positioning signal such as a D (Differential) GPS signal for improvement is received and output to the calculation unit 6 as current position information of the host vehicle Vm.

  The traveling state detection unit 3 includes, for example, a vehicle speed sensor that detects a traveling speed (vehicle speed) of the host vehicle Vm and a yaw rate (a rotational angular velocity about the vertical axis of the center of gravity of the vehicle) as the traveling state information of the host vehicle Vm. It is configured to include an absolute position calculation device that calculates the absolute position coordinates (X, Y, Z) of the host vehicle Vm by appropriately processing the output of the sensor, the vehicle speed sensor, and the yaw rate sensor. The traveling state information of Vm is output to the calculation unit 6.

  The road information storage unit 4 stores node information and curve information related to a road as road data. The node information is, for example, coordinate point data for grasping a road shape, and the curve information is, for example, a link ( That is, in addition to the start and end points of the curve set on the line connecting the nodes), information on the curvature of the curve (for example, the curvature and radius R and polarity of the curve) and the depth of the curve Information (for example, the turning angle θ required for passing the curve, the length of the curve, etc.).

  The two-way radio 5 transmits the traveling state information of the host vehicle Vm (for example, absolute position coordinates, speed, yaw rate, etc. as position information of the host vehicle Vm) via the antenna 5a to other vehicles Vo and base stations (providing information outside the vehicle Equipment) and the other vehicle Vo and the traveling state information of the other vehicle Vo transmitted from the base station 20 (for example, absolute position coordinates, speed, yaw rate, etc. as position information of the other vehicle Vo) received from the other vehicle Vo, The received traveling state information is output to the calculation unit 6.

  The calculation unit 6 includes a CPU (central processing unit), estimates a road surface state based on the traveling state information of the other vehicle Vo received by the two-way wireless device 5, and the own vehicle according to the estimated road surface state Vm deceleration control and warning control are executed.

  The navigation device 7 detects the current position and the traveling direction of the host vehicle Vm based on the current position information of the host vehicle Vm input from the GPS receiver 2 and the absolute position coordinates of the host vehicle detected by the traveling state detection unit 3. Based on the detection result, map matching is performed on the road information stored in the road information storage unit 4 to control the display position of the current position of the host vehicle Vm on the display screen, and the detected host vehicle is detected. The map display on the display screen is controlled with respect to the current position of Vm or an appropriate vehicle position input by the operator via various switches, a keyboard, and the like.

The speaker 8 emits an alarm sound or a synthesized voice according to the control command output from the calculation unit 6. In this embodiment, the speaker 8 constitutes warning means.
The brake device 9 operates the brake actuator of the host vehicle Vm according to the control command output from the calculation unit 6 to perform brake assist (deceleration support).
When there is a possibility of a collision, the seat belt device 10 operates the seat belt actuator of the host vehicle Vm in accordance with a control command output from the calculation unit 6 to retract the seat belt, thereby allowing the passenger of the host vehicle Vm to Give an experiential warning. In this embodiment, the seat belt device 10 constitutes a warning means.

  On the other hand, the other vehicle Vo includes a GPS receiver 2, a traveling state detection unit 3, a road information storage unit 4, a bidirectional wireless device 5, a calculation unit 6, a navigation device 7, and a speaker 8. Since each of these components is the same as that of the host vehicle Vm, description thereof is omitted.

  Next, regarding the driving support process executed in the calculation unit 6 of the driving support device 1 of the host vehicle Vm, as described above, the preceding vehicle (another vehicle) Vo traveling in front of the driving lane of the host vehicle Vm is the curve Dc. The case of spinning will be described as an example with reference to the flowchart of FIG. Note that the driving support processing routine shown in the flowchart of FIG. 3 is repeatedly executed at regular intervals.

In step S01, an estimated travel locus of the host vehicle Vm is calculated based on an input from the travel state detection unit 3 of the host vehicle Vm.
Next, it progresses to step S02 and it is determined based on the positional information on the preceding vehicle Vo acquired via the bidirectional | two-way radio 5 whether the preceding vehicle Vo exists on the estimated driving | running locus of the own vehicle Vm.
If the determination result in step S02 is “NO”, the execution of this routine is temporarily terminated.

If the determination result in step S02 is “YES”, the process proceeds to step S03, and the relative distance between the host vehicle Vm and the preceding vehicle Vo is calculated based on the absolute position coordinates of the host vehicle Vm and the preceding vehicle Vo. Based on the movement history of the preceding vehicle Vo, the moving speed of the preceding vehicle Vo is calculated.
Next, the process proceeds to step S04, and when the host vehicle Vm and the preceding vehicle Vo maintain the current traveling state based on the relative speed calculated from the vehicle speed of the host vehicle Vm and the moving speed of the preceding vehicle Vo and the relative distance. A time until the host vehicle Vm comes into contact with the preceding vehicle Vo (collision time TTC) is calculated.

Next, the process proceeds to step S05, and a stop deceleration G necessary for the host vehicle Vm to stop before the preceding vehicle Vo from the current position is calculated.
Next, the process proceeds to step S06, and the road surface state at the current position of the preceding vehicle Vo is estimated based on the traveling state information of the preceding vehicle Vo. The estimation of the road surface state is performed by estimating the road surface μ based on the yaw rate of the other vehicle Vo or based on the vehicle front direction of the preceding vehicle Vo. The road surface state estimation process will be described later.

Next, the process proceeds to step S07, and a target deceleration Gt corresponding to the road surface μ estimated in step S06 is set. Here, the target deceleration Gt is set to a smaller value as the road surface μ is smaller, and the brake assist is executed from a point farther when the road surface μ is larger than when the road surface μ is large.
Next, proceeding to step S08, it is determined whether or not the target deceleration Gt set at step S07 is smaller than the stop deceleration G calculated at step S05.

If the determination result in step S08 is “YES” (Gt <G), the process proceeds to step S09 to output a maximum braking command to the brake device 9 in order to execute maximum braking on the host vehicle Vm. Routine execution is temporarily terminated. That is, if the host vehicle Vm is braked so as to achieve the target deceleration Gt corresponding to the road surface μ, it will come into contact with the preceding vehicle Vo. In this case, the maximum braking is used.
On the other hand, if the determination result in step S08 is “NO” (Gt ≧ G), a braking control command is output to the brake device 9 so that a braking force that achieves the target deceleration Gt is obtained, and execution of this routine is executed. Is temporarily terminated.
As described above, according to the driving support device 1, the vehicle deceleration control and the warning to the occupant can be executed in accordance with the road surface state where the preceding vehicle Vo is located. The collision avoidance can be appropriately performed, and a warning to the occupant can be performed at an appropriate timing.

Next, the road surface state estimation process executed in step S06 will be described with reference to the flowcharts of FIGS.
FIG. 4 is a flowchart showing a road surface state estimation process for estimating the road surface μ based on the yaw rate of the other vehicle Vo.
First, curve information in the forward direction of the estimated travel locus is acquired from the road information storage unit 4 (step S101), and the preceding vehicle Vo does not spin based on the radius R of the forward curve and the moving speed of the preceding vehicle Vo. The yaw rate value (reference yaw rate) generated when the vehicle travels is calculated and set to the first determination threshold Y0 (step S102).

Next, it is determined whether or not the moving speed of the preceding vehicle Vo acquired via the two-way radio device 5 is equal to or less than a predetermined value (step S103). To do. If the moving speed of the preceding vehicle Vo is equal to or less than the predetermined value, it is determined whether or not the actual yaw rate value Y of the preceding vehicle Vo acquired via the two-way wireless device 5 is equal to or greater than the first determination threshold Y0 (step). S104) If the actual yaw rate value Y is greater than or equal to the first determination threshold Y0, it is determined that the preceding vehicle Vo has spun, and it is determined that the road surface μ is low enough to spin (step S105). The execution of is temporarily terminated. On the other hand, when the actual yaw rate value Y is smaller than the first determination threshold value Y0, it is determined that the road surface μ is normal (corresponding to a dry paved road) (step S106), and the execution of this routine is temporarily terminated.
Thus, the road surface μ can be appropriately estimated based on the yaw rate of the preceding vehicle Vo.

FIG. 5 is a flowchart showing a road surface state estimation process for estimating the road surface μ based on the vehicle front direction of the other vehicle Vo.
First, the vehicle front direction θi of the preceding vehicle Vo is calculated (estimated) by integrating the yaw rate values of the preceding vehicle Vo acquired via the two-way radio device 5 (step S201).
Next, based on the position information of the preceding vehicle Vo acquired via the two-way radio 5, road information where the preceding vehicle Vo is acquired is acquired from the road information storage unit 4, and the traveling direction of the road where the preceding vehicle Vo is located (Road traveling direction) θd is read (step S202).

Then, a deviation Δθ between the vehicle front direction θi of the preceding vehicle Vo and the traveling direction θd of the road on which the preceding vehicle Vo is located is calculated (step S203), and it is determined whether the deviation Δθ is equal to or greater than a second determination threshold value (step S203). Step S204).
If the deviation Δθ is greater than or equal to the second determination threshold value, it is determined that the preceding vehicle Vo has spun, it is determined that the road surface μ is low enough to spin (step S205), and the execution of this routine is temporarily terminated. . On the other hand, when the deviation Δθ is smaller than the second determination threshold value, it is determined that the road surface μ is normal (corresponding to a dry paved road) (step S206), and the execution of this routine is temporarily ended.
In step S205, it is also possible to estimate the size of the road surface μ according to the size of the deviation Δθ. In this case, it is estimated that the road surface μ is smaller as the deviation Δθ is larger.
As described above, the road surface μ can be appropriately estimated based on the deviation Δθ between the vehicle front direction θi of the preceding vehicle Vo and the road traveling direction θd.

The present invention is not limited to the embodiments described above.
For example, in the above-described embodiment, the road surface state (road surface μ) at the current position of the preceding vehicle Vo is estimated based on the traveling state information of the preceding vehicle Vo, and the braking control according to the road surface μ is executed. In parallel with the braking control, warning control for changing the warning level according to the estimated road surface μ may be executed. For example, when a pretensioner that pulls in the seat belt and warns the occupant is equipped, if the target deceleration Gt set according to the estimated road surface μ is 0.2 G or less, a plurality of seat belts are used. A control command is output to the seat belt device 10 so as to pull the seat belt weakly. When the target deceleration Gt is greater than 0.2G and equal to or less than 0.4G, a control command is issued to the seat belt device 10 so as to pull the seat belt strongly. It may be output.
In the case where a warning sound is issued from the speaker 8 to warn the occupant, the volume of the warning sound of the speaker 8 is increased or the warning sound is intermittently emitted as the target deceleration Gt increases. The generation period of the alarm sound may be shortened as the target deceleration Gt increases.

In the above-described embodiment, the preceding vehicle that travels in the travel lane of the host vehicle is the other vehicle. However, the oncoming vehicle that travels in the oncoming lane can be the other vehicle, and travel support of the host vehicle can be performed.
In the above-described embodiment, the driving state information of the other vehicle is acquired in real time by the inter-vehicle communication with the other vehicle and the collision with the other vehicle is avoided. However, the present invention is limited to the collision avoidance. Rather than, for example, for so-called curve approach brake assist, which assists deceleration by intervening an intervention brake (for example, a brake assist device, an automatic brake device, etc.) when the host vehicle enters the curve for stable driving of the curve. Is also applicable. In that case, it is not necessary to acquire the driving state information of the other vehicle in real time, for example, the driving state of the unspecified other vehicle stored in the base station 20 in the past (for example, from the present to a predetermined time before). It may be information, and the road surface state of the curve can be estimated based on the past traveling state information of other vehicles.
The base station (exterior information providing facility) 20 may be a roadside facility or a server on the Internet.

It is a functional block diagram in the Example of the driving assistance device of the vehicle concerning this invention. It is explanatory drawing which shows the case where the driving assistance device of the own vehicle act | operates with respect to the preceding vehicle spun on the front curve. It is a flowchart which shows the driving | running | working assistance process in the said Example. It is a flowchart which shows an example of the road surface state estimation process in the said Example. It is a flowchart which shows the other example of the road surface state estimation process in the said Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle travel assistance apparatus 2 GPS receiver (position detection means)
3 Running state detection unit (running state detection means)
4 Road information storage unit (storage means)
5. Two-way radio (communication means)
6 Calculation unit (running support means)
20 Base station (off-vehicle information provision facility)
Vm Own vehicle Vo Preceding vehicle (other vehicles)

Claims (5)

A communication means mounted on the vehicle and capable of communicating with the outside information providing facility or another vehicle;
Driving support means for supporting driving of the vehicle based on the information acquired by the communication means;
In a vehicle driving support device comprising:
Storage means for storing road information;
Position detecting means for detecting a vehicle position on the road stored in the storage means;
Traveling state detecting means for detecting the traveling state of the vehicle;
The communication means transmits and receives vehicle position information and travel state information to / from the outside information providing facility or other vehicle, and the travel support means is based on the travel state information of the other vehicle acquired by the communication means. A vehicle driving support apparatus that estimates a road surface state of the other vehicle at a vehicle position and performs deceleration control of the host vehicle or a warning to an occupant based on the estimated road surface state. The running state detecting means includes a yaw rate sensor for detecting a yaw rate of the vehicle,
The travel support means has a moving speed of the other vehicle calculated from vehicle position information of the other vehicle acquired by the communication means that is a predetermined value or less, and the yaw rate of the other vehicle acquired by the communication means. 2. The vehicle travel support device according to claim 1, wherein when the value of the vehicle is equal to or greater than a first determination threshold value, it is determined that the friction coefficient of the road surface at the vehicle position of the other vehicle is low.   The vehicle travel support apparatus according to claim 2, wherein the first determination threshold is calculated based on a moving speed of another vehicle and road information stored in the storage unit.   The travel support means estimates the vehicle front direction of the other vehicle based on the travel state of the other vehicle acquired by the communication means, and stores the estimated vehicle front direction of the other vehicle and the storage means. 2. The vehicle travel support apparatus according to claim 1, wherein when the deviation from the road traveling direction is equal to or greater than a second determination threshold value, it is determined that the friction coefficient of the road surface at the vehicle position of the other vehicle is low. .   The travel support means determines that the greater the deviation between the estimated vehicle front direction of the other vehicle and the road traveling direction stored in the storage means, the lower the friction coefficient of the road surface at the vehicle position of the other vehicle. The vehicle travel support apparatus according to claim 4.

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