JP2003308600A - Curve notice device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely notify an occupant of the road shape in front of an own car position. <P>SOLUTION: After this curve notice device determines the road shape in front of the own car position based on map information, if the road shape is not a straight line but a curve and the curve is a simple curve (steps S4 and S5), this device gives a notice of the curve to a driver (step S6). If the curve is an S-shaped curve or a crank road, this device gives the notice of the S-shaped curve or the crank road to the driver (step S7). When the present speed of the own car is too excessive to pass the curve, this device issues an alarm to the driver (steps S8 and S9) and if automatic deceleration is required, the automatic deceleration is executed (steps S10-S12). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle curve advance notice device for determining a road shape ahead of a vehicle position based on map information and giving an advance notice when the road shape is a curve.

[0002]

2. Description of the Related Art A transmitter provided in front of an entrance of a curve transmits information about an approaching speed and a steering angle necessary for smoothly passing through the curve as information for giving an occupant of an automobile a road shape. Is known from Patent Document 1 below. Also, the slope of the road stored in the CD-ROM,
Japanese Patent Application Laid-Open Publication No. 2003-242242 discloses a device for controlling an auto cruise device of an automobile based on information on a road surface condition and a curve radius.

[0003]

[Patent Document 1] Japanese Patent Laid-Open No. 3-149700

[Patent Document 2] Japanese Patent Laid-Open No. 4-15799

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to surely notify the occupant of the road shape in front of the vehicle position.

[0005]

In order to achieve the above object, according to the invention described in claim 1, it is determined based on the map information whether the road shape in front of the vehicle position is a curve. However, if it is a curve, the road shape determination means for determining whether it is a simple curve, an S-shaped curve or a crank road, and when the road shape determination means determines that the road shape is a curve, the curve is A curve advance notice device for a vehicle is proposed, which is provided with an advance notice device that gives advance notice of whether it is a simple curve, an S-shaped curve, or a crank path.

According to the invention described in claim 2,
In addition to the configuration of claim 1, when the road shape determination means determines that the road shape is a curve, it is determined whether or not the current vehicle speed is excessive with respect to the vehicle speed that can turn the curve. A curve advance notice device for a vehicle is proposed, which is characterized in that when a vehicle speed is excessively high with respect to a vehicle speed capable of turning a curve, an alarm means issues an alarm to an occupant.

According to the invention described in claim 3,
In addition to the configuration of claim 2, when the vehicle speed is not decelerated to a vehicle speed at which the vehicle can turn a curve despite the warning by the warning means, the vehicle speed adjustment means automatically decelerates the vehicle curve. Is proposed.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on the embodiments of the present invention shown in the accompanying drawings.

1 to 7 show a first embodiment of the present invention, and FIG. 1 is a block diagram showing the overall configuration of the device of the present invention,
2 is a block diagram of the control system, FIG. 3 is a flow chart showing the operation, FIG. 4 is an explanatory diagram showing how to obtain the road shape, FIG. 5 is an explanatory diagram of a method of extracting reference coordinate points, and FIG. 6 is a road shape pattern. FIG. 7 is a diagram showing a road shape determination standard.

In FIG. 1, NV is a navigation system for automobiles, in which a well-known navigation device 1,
Map information output means 2 using an IC card or CD-ROM
And a control unit 3 for performing various calculations to be described later.

The navigation device 1 receives a signal from the vehicle speed detecting means 6 in addition to the vehicle position information, road information, traffic information and the like from the satellite communication device 4 or the near field communication device 5, and this and the map information output means. Based on the map information from 2, the current position of the vehicle and the route to the destination are calculated and displayed on the CRT 9 via the man-machine interface 8.

The map information output by the map information output means 2 is composed of a set of virtual nodes N arranged on the road, and each node N has a coordinate N (X, Y).
Stipulated by When a road has a bend, a branch, or an intersection, those singular points are given priority to the node N.
Has been selected as.

The control unit 3 performs various calculations, which will be described later, based on the outputs of the navigation device 1, the map information output unit 2 and the vehicle speed detection unit 6, displays the results, and issues an alarm and vehicle speed control.

Reference numeral C denotes a vehicle speed adjusting device, which is provided with an image creating means 11, a warning means 12 and a vehicle speed adjusting means 13 therein. The image creating means 11 is composed of, for example, a head-up display, and displays the determined road shape in the front, the vehicle speed that can be passed, and the like. The warning means 12 is composed of a sounding means such as a buzzer or a chime, and gives various warnings to an occupant. The vehicle speed adjusting means 13 is composed of a brake device, an auto cruise device, etc., and automatically adjusts the vehicle speed so that the vehicle can pass through a curve.

FIG. 2 is a block diagram showing a control system of the present invention, which includes map information output means M1 corresponding to the map information output means 2 and own vehicle position output means M2 corresponding to the navigation device 1. Reference coordinate point extraction means M3, angle calculation means M4, and road shape determination means M5 corresponding to the control unit 3.
And a display means M7 corresponding to the image creating means 11.

The reference coordinate point extraction means M3 is used to determine the road shape from a large number of nodes N set on the road.
The nodes N ₁ , N ₂ , N ₃ , and N ₄ (hereinafter referred to as reference nodes) are extracted.

The angle calculation means M4 has a reference node N.₁, N
₂Vector V that connects the two ₁₂And reference node
N₂, N₃Vector V that connects the two_{twenty three}With
Angle θ₁And the reference node N₁, N₂To
Vector V, which is the connecting vector₁₂And reference node N₂, N
_FourVector V that connects the two_{twenty four}Angle θ formed by₂
To calculate the angle θ₁And θ₂From the road shape
To calculate the change rate α. The calculation method of the rate of change α will be
Detailed description.

The road shape judging means M5 judges the road shape by comparing the change rate α with a predetermined reference value.

Next, the operation of the first embodiment of the present invention will be described based on the flowchart of FIG.

First, the map information (that is, the coordinates N (X, Y) of the node N is read from the map information output means M1 and the own vehicle position P ₀ (X ₀ , Y) is read from the own vehicle position output means M2.
₀ ) is read, and the vehicle speed V ₀ is read from the vehicle speed detecting means 6 (step S1).

Next, the prefetch section S ₁ and the judgment section S ₂ are calculated (step S2). As shown in FIG. 4, the prefetch section S ₁ is set in front of the vehicle position P ₀ , and is the product of the current vehicle speed V ₀ and the predetermined time t ₁ (S ₁ = V ₀ ×
distance for stopping the predetermined time t ₁ within the case of performing either set, or the braking at a predetermined deceleration β as _{t 1) (S 1 = V} 0 t 1 - (βt 1 2/2)) Is set as. The look-ahead section S ₁ is for giving a passenger a time margin for braking or steering after determining the road shape in front of the vehicle.

The determination section S ₂ is set in a predetermined range in front of the front end of the look-ahead section S ₁ (hereinafter referred to as the temporary vehicle position). For example, the current vehicle speed V ₀ and the predetermined time t.
It is set as the product of the _{2 (S 2 = V 0 ×} t 2).

Next, the reference coordinate point extraction means M3, 4 nodes for determining the road shape N ₁ to N ₄ (hereinafter, referred to as the reference node N ₁ to N ₄₎ to extract (step S3). The second reference node N ₂ is set at the temporary vehicle position, the first reference node N ₁ is located at a position a distance a from the second reference node N ₂ , and the third reference node N ₃ is located at the second reference node N _2. Is set to the front position by the distance a, and the fourth reference node N ₄ is set to the front position by the distance a of the third reference node N ₃ . Here, a is set as a constant or the product of the vehicle speed V ₀ and the predetermined time t ₃ (a = V ₀ × t ₃ ).

If the node N does not exist at a position set by a multiple of the distance a with respect to the temporary vehicle position, the node N closest to the position is the reference node N ₁
~ N ₄ is extracted.

Further, in this embodiment, the reference nodes N _{1 to} N _{4 are used.}
However, when the number of nodes N set on the road is small (that is, when the nodes are sparse), the adjacent nodes N may be extracted as they are.

Further, as shown in FIG. 5 (A), the S-shaped curve has the strictest passage conditions among the composite curves, but when the distance a is set as a constant, a = 30 m.
By so doing, it is possible to reliably determine even a compact S-shaped curve in which two arcs having a radius of curvature R = 30 m are connected.

Further, as shown in FIG. 5B, when a bent road such as a crank road exists in the judgment section S ₂ , the node N (singular point) corresponding to the bent point is given priority. The reference nodes N _{1 to} N ₄ . This allows
It is possible to reliably determine a special road shape such as a crank road.

Next, the road shape is determined based on the coordinates of the _four reference nodes N _{1 to} N ₄ (step S4).

First, the angle θ is calculated by the angle calculation means M4.
Calculate ₁ and θ ₂ . That is, as shown in FIG.
Reference node N ₁ (X ₁ , Y ₁ ) and second reference node N
Vector V ₁₂ (X ₁₂ , Y ₁₂ ) connecting with ₂ (X ₂ , Y ₂ ).
And a vector V ₂₃ (X ₂₃ , Y) connecting the second reference node N ₂ (X ₂ , Y ₂ ) and the third reference node N ₃ (X ₃ , Y ₃ ).
₂₃ ) and a vector V connecting the second reference node N ₂ (X ₂ , Y ₂ ) and the fourth reference node N ₄ (X ₄ , Y ₄ ).
₂₄ (X ₂₄ , Y ₂₄ ) is calculated.

[0030] At this time, when the angle formed by the vector V ₁₂ and the vector V ₂₃ and theta _1, from the inner product of the vector V ₁₂ and the vector _{V 23, X 12 · X 23} + Y 12 · Y 23 = (X 12 2 + Y ₁₂ ² ) ^1/2 · (X ₂₃ ² + Y ₂₃ ² ) ^1/2 · cos θ ₁ holds, and cos θ ₁ is obtained from this.

Further, the vector V₁₂And vector V_{twenty four}Success with
Angle θ₂Then, the vector V ₁₂And vector V_{twenty four}
From the dot product of   X₁₂・ X_{twenty four}+ Y₁₂・ Y_{twenty four}         = (X₁₂ ²+ Y₁₂ ²)^1/2・ (X_{twenty four} ²+ Y_{twenty four} ²)^1/2・ Cos θ₂… Holds, and from now on, cos θ₂Is required.

Next, the rate of change α is calculated by α = (cos θ ₁ -cos θ ₂ ) / cos θ ₁ ...

As is clear from the equation, when the absolute value of the rate of change α is small, it corresponds to the case where θ ₁ and θ ₂ are substantially the same and the bend of the road is small (that is, straight road), Conversely, when the absolute value of the rate of change α is large, θ ₁ and θ
₂ is very different and corresponds to a case where the road has a large bend (that is, a crank road or a sharp curve).

Note that the direction of curve of the road is the vector V₁₂as well as
Vector V_{twenty three}Cross product of X₁₂・ Y _{twenty three}-Y₁₂・ X_{twenty three}Positive
It can be judged by the negative.

Thus, as shown in FIGS. 6 and 7, the road shape determination means M5 determines various road shapes according to the value of the change rate α.

If the road shape determined as described above is a curve (step S4), it is further determined whether the curve is an S curve or a crank road (step S4).
5). If the road shape is simply a curve, the advance notice of the curve is displayed on the display means M7 (step S
6) If the road shape is an S-curve or a crank road that is difficult to pass, a notice of the S-curve or crank road is displayed on the display means M7 (step S7).

Next, it is determined whether or not the current vehicle speed V ₀ is appropriate for the determined road shape (step S8), and the current vehicle speed V 0 is set.
_{When 0} is too high for the vehicle speed at which the vehicle can turn the curve ahead, the warning means 12 gives a warning to the occupant (step S9). If the vehicle speed is not decelerated to an appropriate vehicle speed at which the vehicle can surely turn the curve despite the warning (step S10), the vehicle speed adjusting means 13 automatically decelerates (step S11). Then, when the host vehicle passes through the target curve or the vehicle speed V ₀ is decelerated to the proper vehicle speed (step S12), the automatic deceleration is stopped and the process returns to step S1.

On the other hand, the answer of the step S8, S10 is equal is not required automatic deceleration NO, the determining whether the process has been performed for the entire area of the judgment section S ₂ (step S1
3), the answer is returned to step S3 if not processing has been completed for the entire area of the determination section S ₂ comprising NO, the reference node N ₁ to N ₄ is shifted to the front side repeats the processing described above, As a result, the answer in step S13 is YE.
When S is reached and all processing is completed, the process returns to step S1.

As described above, the coordinates N of the plurality of nodes N
Since the road shape is determined based on the map information consisting of a set of (X, Y), it is not necessary to maintain the infrastructure, which requires high equipment costs and maintenance costs.
The road shape can be determined with the minimum amount of data that can be stored in the M or the IC card.

Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a block diagram corresponding to FIG. 2 of the first embodiment, FIG. 9 is an explanatory diagram of a difference, FIG. 10 is an explanatory diagram showing how to obtain a road shape, and FIG. 11 shows how to obtain a radius of curvature of an arc curve. Explanatory diagram, FIG. 12 is a diagram showing a road shape pattern, FIG. 13 is a diagram showing a road shape pattern, FIG.
FIG. 15 is an explanatory diagram showing a method of determining a non-circular curve, and FIG. 15 is a diagram showing criteria for determining a road shape.

In the second embodiment, the road shape is judged based on _three reference nodes N ₁ , N ₂ and N ₃ which are adjacent to each other. As shown in FIG. 8, the output of the angle calculating means M4 and the distance are calculated. It differs from the first embodiment in that the road shape is determined based on the output of the calculating means M6, and the other configurations are the same as those in the first embodiment.

In the map information of the second embodiment, as a rule for creating data, the distance (hereinafter, referred to as a difference) between a line segment connecting adjacent nodes N and a road is set to a predetermined reference value k or less. The position of each node N is determined. That is, FIG.
As shown in (1), in the portion where the radius of curvature of the road is small, the difference is suppressed to the reference value k or less by setting the distance between the adjacent nodes N small.

The extraction of the _three reference nodes N ₁ , N ₂ and N ₃ is performed as follows. That is, the first reference node N ₁ on the most front side among the three reference nodes to be first extracted N _1, N _2, N ₃ is set to the tip of the pre-read interval S _1, nodes adjacent to the front N is the second reference node N ₂
And the node N adjacent to the node in front of it is set as the third reference node N ₃ . These three reference nodes N ₁ ,
N ₂ and N ₃ are sequentially extracted by shifting to the front side.

Next, a method of determining the road shape based on the coordinates of the _three reference nodes N _{1 to} N ₃ will be described. .

First, as shown in FIG. 10, angle calculation means
The first reference node N by M4₁(X ₁, Y₁) And the second group
Quasi node N₂(X₂, Y₂) Vector V connecting with₁₂(X
₁₂, Y₁₂) And the second reference node N₂(X₂, Y₂) And the first
3 reference node N₃(X₃, Y ₃) Vector V connecting with_{twenty three}
(X_{twenty three}, Y_{twenty three}) Is calculated.

That is, from the inner product of the vector V ₁₂ and the vector V ₂₃ , X ₁₂ · X ₂₃ + Y ₁₂ · Y ₂₃ = (X ₁₂ ² + Y ₁₂ ² ) ^1/2 · (X ₂₃ ² + Y ₂₃ ² ) ^1/2・ Cos θ is established, and the angle θ is obtained from this.

Next, the distance calculating means M6 causes the first reference
Code N₁(X₁, Y₁) And the second reference node N₂(X₂，
Y₂) Distance L₁₂And the second reference node N₂(X₂, Y
₂) And the third reference node N₃(X₃, Y₃) Distance L_{twenty three}
And the first reference node N₁(X ₁, Y₁) And the third standard no
De N₃(X₃, Y₃) Distance L₁₃And are calculated.

[0048] L₁₂= (X₁₂ ²+ Y₁₂ ²)^1/2                  … L_{twenty three}= (X_{twenty three} ²+ Y_{twenty three} ²)^1/2                  … L₁₃= (X₁₃ ²+ Y₁₃ ²)^1/2                  … Here, the first reference node N₁(X₁, Y₁) And the third criterion
Node N₃(X₃, Y ₃) And the vector connecting
Le V₁₃(X₁₃, Y₁₃).

As is apparent from FIG. 11, when it is assumed that the _three reference nodes N _{1 to} N ₃ exist on a common arc, that is, when the curve is an arc-shaped curve, L ₁₂ ≈L ₂₃
If so, the radius of curvature R of the arc-shaped curve is obtained by R = L ₁₃ / (2 sin θ) ... And it is possible to determine whether or not the curve can pass based on this radius of curvature R.

As described above, the three reference nodes N ₁ ...
When the angle θ and the distance L ₁₃ are obtained from N _3, the road shape can be determined based on the magnitude of the angle θ and the magnitude of the distance L ₁₃ . That is, as shown in FIG.
Is larger and the distance L ₁₃ is smaller, the radius of curvature of the curve is smaller, and as the angle θ is smaller and the distance L ₁₃ is larger, the radius of curvature of the curve is larger.

By the way, when the three reference nodes N _{1 to} N ₃ exist on a common arc, that is, when the curve is an arc-shaped curve, the road shape can be determined as shown in FIG. However, other than the arc-shaped curve, the curve entrance where the radius of curvature gradually decreases and the curve exit where the radius of curvature gradually increases can be determined as follows.

As shown in FIG. 14, three reference nodes N
Assuming that _{1 to} N ₃ are on a common circular arc, the radius of curvature R is calculated as described above, and the difference between the longer one of the vectors V ₁₂ , V ₂₃ and the circular arc of the radius of curvature R is obtained. If the calculated difference is within the range of the reference value k, it is confirmed that the _three reference nodes N _{1 to} N ₃ are on the arc of the radius of curvature R, but the calculated difference is the reference value k. If it exceeds, it is unlikely that the three reference nodes N _{1 to} N ₃ exist on the arc, and the _three reference nodes N _{1 to} N ₃ have non-arc curves with gradually changing radii of curvature (ie, It is determined to be on the curve entrance or the curve exit).

This will be described in more detail as shown in FIG.
And the first reference node N₁And the second reference node N₂Distance from
L₁₂Is the second reference node N₂And the third reference node N₃Distance from
Distance L _{twenty three}Larger than the first reference node N₁And the second standard
Code N₂Vector V connecting to ₁₂And three reference nodes N₁
~ N₃If the difference with the arc passing through exceeds the reference value k,
Road shape is a curve entrance with a gradually decreasing radius of curvature
Is determined. On the other hand, the distance L_{twenty three}Is the distance L₁₂Greater than
Vector V_{twenty three}The difference between the arc and the arc exceeds the reference value k.
If so, the road shape will be a curve exit with a gradually increasing radius of curvature.
It is determined that

[0054] In Thus, in FIG. 15, the angle region of θ is large distance L ₁₃ is smaller lower right radius of curvature R is less rapid curves, intersections, corresponding to the branch path or the like, the angle θ is small distance L ₁₃ The lower right region with a large radius corresponds to a gentle curve or straight road with a large radius of curvature R. Further, k _{1 to} k ₄ represent the standard value of the difference (k ₁ > k ₂ > k ₃ > k ₄ ),
If the point determined by the calculated angle θ and the distance L ₁₃ is, for example, in the lower left area of the reference value k ₂ , the road shape is an arc curve with a constant radius of curvature, and in the upper right area of the reference value k _2. If so, the road shape is a non-circular curve with a gradually changing radius of curvature.

If the determined road shape is a non-circular curve,
The radius of curvature for determining whether the curve can pass or not
Is asked for. That is, obtained in FIG.
The radius of curvature R does not reflect the actual radius of curvature,
Near the exit (ie, the second reference node N₂And the third standard no
De N₃The actual radius of curvature of
Get smaller. Therefore, the first reference node N₁And the second standard
Node N₂The second reference node N on the line segment connecting₂Distance from
L_{twenty three}Position N₁'Takes 3 points N₁′, N₂, N ₃Through
If the radius of curvature R'of the arc
Make sure that the radius of curvature is appropriate for determining whether the curve can pass.
It

Although the embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various design changes can be made.

[0057]

As described above, according to the invention described in claim 1, when it is determined that the road shape is a curve,
Since it is announced whether the curve is a simple curve or a continuous curve (that is, an S-shaped curve or a crank road), the occupant can be surely notified of the road shape.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of a device of the present invention.

FIG. 2 is a block diagram of a control system

FIG. 3 is a flowchart showing the operation.

FIG. 4 is an explanatory diagram showing how to obtain a road shape.

FIG. 5 is an explanatory diagram of a method of extracting reference coordinate points.

FIG. 6 is a diagram showing a road shape pattern.

FIG. 7 is a diagram showing criteria for determining a road shape.

FIG. 8 is a block diagram corresponding to FIG. 2 according to a second embodiment.

FIG. 9 is an explanatory diagram of a difference

FIG. 10 is an explanatory diagram showing how to obtain a road shape.

FIG. 11 is an explanatory diagram showing how to determine the radius of curvature of an arc curve.

FIG. 12 is a diagram showing a road shape pattern.

FIG. 13 is a diagram showing a road shape pattern.

FIG. 14 is an explanatory diagram showing a method of determining a non-circular curve.

FIG. 15 is a diagram showing criteria for determining a road shape.

[Explanation of symbols] M5 Road shape determination means M7 display means (preliminary means) 12 Warning means 13 Vehicle speed adjustment means

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 30, 2003 (2003.6.3
0)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title of vehicle curve advance notice device

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle curve advance notice device for determining a road shape ahead of a vehicle position based on map information and giving an advance notice when the road shape is a curve.

[0002]

2. Description of the Related Art A transmitter provided in front of an entrance of a curve transmits information about an approaching speed and a steering angle necessary for smoothly passing through the curve as information for giving an occupant of an automobile a road shape. Is known from Patent Document 1 below. Also, the slope of the road stored in the CD-ROM,
Japanese Patent Application Laid-Open Publication No. 2003-242242 discloses a device for controlling an auto cruise device of an automobile based on information on a road surface condition and a curve radius.

[0003]

[Patent Document 1] Japanese Patent Laid-Open No. 3-149700

[0004]

[Patent Document 2] Japanese Patent Laid-Open No. 4-15799

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to surely notify the occupant of the road shape in front of the vehicle position.

[0006]

In order to achieve the above object, according to the invention described in claim 1, it is set on a road.
Has been determined whether the road shape ahead of the vehicle position based on the coordinates of the nodes of the map information is curved, either simply curved if the curve, or an S-shaped curve or a crank road and the road shape determining means for determining, when the road shape ahead of the vehicle position is determined to be curved by its <br/> road shape determining means, whether the curve is merely curved, S-shaped curve or A curve advance notice device for a vehicle is proposed, which is provided with advance notice means for giving advance notice of whether the vehicle is on a crank road.

Further, according to the invention described in claim 2,
In addition to the configuration of claim 1, when the road shape determination means determines that the road shape is a curve, it is determined whether or not the current vehicle speed is excessive with respect to the vehicle speed that can turn the curve. A curve advance notice device for a vehicle is proposed, which is characterized in that when a vehicle speed is excessively high with respect to a vehicle speed capable of turning a curve, an alarm means issues an alarm to an occupant.

According to the invention described in claim 3,
In addition to the configuration of claim 2, when the vehicle speed is not decelerated to a vehicle speed at which the vehicle can turn a curve despite the warning by the warning means, the vehicle speed adjustment means automatically decelerates the vehicle curve. Is proposed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on the embodiments of the present invention shown in the accompanying drawings.

1 to 7 show a first embodiment of the present invention, and FIG. 1 is a block diagram showing the overall configuration of the device of the present invention,
2 is a block diagram of the control system, FIG. 3 is a flow chart showing the operation, FIG. 4 is an explanatory diagram showing how to obtain the road shape, FIG. 5 is an explanatory diagram of a method of extracting reference coordinate points, and FIG. 6 is a road shape pattern. FIG. 7 is a diagram showing a road shape determination standard.

In FIG. 1, NV is a navigation system for automobiles, in which a well-known navigation device 1,
Map information output means 2 using an IC card or CD-ROM
And a control unit 3 for performing various calculations to be described later.

The navigation device 1 receives a signal from the vehicle speed detecting means 6 in addition to the vehicle position information, road information, traffic information, etc. from the satellite communication device 4 or the near field communication device 5, and the map information output means. Based on the map information from 2, the current position of the vehicle and the route to the destination are calculated and displayed on the CRT 9 via the man-machine interface 8.

The map information output by the map information output means 2 is composed of a set of virtual nodes N arranged on the road, and each node N has a coordinate N (X, Y).
Stipulated by When a road has a bend, a branch, or an intersection, those singular points are given priority to the node N.
Has been selected as.

The control unit 3 performs various calculations to be described later based on the outputs of the navigation device 1, the map information output unit 2 and the vehicle speed detection unit 6, displays the results, and issues an alarm and vehicle speed control.

Reference numeral C denotes a vehicle speed adjusting device, which has an image creating means 11, an alarm means 12, and a vehicle speed adjusting means 13 inside. The image creating means 11 is composed of, for example, a head-up display, and displays the determined road shape in the front, the vehicle speed that can be passed, and the like. The warning means 12 is composed of a sounding means such as a buzzer or a chime, and gives various warnings to an occupant. The vehicle speed adjusting means 13 is composed of a brake device, an auto cruise device, etc., and automatically adjusts the vehicle speed so that the vehicle can pass through a curve.

FIG. 2 is a block diagram showing a control system according to the present invention. Map information output means M1 corresponding to the map information output means 2, vehicle position output means M2 corresponding to the navigation device 1, Reference coordinate point extraction means M3, angle calculation means M4, and road shape determination means M5 corresponding to the control unit 3.
And a display means M7 corresponding to the image creating means 11.

The reference coordinate point extracting means M3 is used to determine the road shape from a large number of nodes N set on the road.
The nodes N ₁ , N ₂ , N ₃ , and N ₄ (hereinafter referred to as reference nodes) are extracted.

The angle calculation means M4 has a reference node N.₁, N
₂Vector V that connects the two ₁₂And reference node
N₂, N₃Vector V that connects the two_{twenty three}With
Angle θ₁And the reference node N₁, N₂To
Vector V, which is the connecting vector₁₂And reference node N₂, N
_FourVector V that connects the two_{twenty four}Angle θ formed by₂
To calculate the angle θ₁And θ₂From the road shape
To calculate the change rate α. The calculation method of the rate of change α will be
Detailed description.

The road shape judging means M5 judges the road shape by comparing the rate of change α with a predetermined reference value.

Next, the operation of the first embodiment of the present invention will be described based on the flowchart of FIG.

First, the map information (that is, the coordinates N (X, Y) of the node N is read from the map information output means M1 and the own vehicle position P ₀ (X ₀ , Y) is read from the own vehicle position output means M2.
₀ ) is read, and the vehicle speed V ₀ is read from the vehicle speed detecting means 6 (step S1).

Next, the prefetch section S ₁ and the judgment section S ₂ are calculated (step S2). As shown in FIG. 4, the prefetch section S ₁ is set in front of the vehicle position P ₀ , and is the product of the current vehicle speed V ₀ and the predetermined time t ₁ (S ₁ = V ₀ ×
distance for stopping the predetermined time t ₁ within the case of performing either set, or the braking at a predetermined deceleration β as _{t 1) (S 1 = V} 0 t 1 - (βt 1 2/2)) Is set as. The look-ahead section S ₁ is for giving a passenger a time margin for braking or steering after determining the road shape in front of the vehicle.

The determination section S ₂ is set in a predetermined range in front of the front end of the prefetch section S ₁ (hereinafter referred to as the temporary vehicle position). For example, the current vehicle speed V ₀ and the predetermined time t.
It is set as the product of the _{2 (S 2 = V 0 ×} t 2).

Next, the reference coordinate point extraction means M3, 4 nodes for determining the road shape N ₁ to N ₄ (hereinafter, referred to as the reference node N ₁ to N ₄₎ to extract (step S3). The second reference node N ₂ is set at the temporary vehicle position, the first reference node N ₁ is located at a position a distance a from the second reference node N ₂ , and the third reference node N ₃ is located at the second reference node N _2. Is set to the front position by the distance a, and the fourth reference node N ₄ is set to the front position by the distance a of the third reference node N ₃ . Here, a is set as a constant or the product of the vehicle speed V ₀ and the predetermined time t ₃ (a = V ₀ × t ₃ ).

If the node N does not exist at a position set by a multiple of the distance a with respect to the temporary vehicle position, the node N closest to that position is the reference node N ₁
~ N ₄ is extracted.

Further, in this embodiment, the reference nodes N _{1 to} N _{4 are used.}
However, when the number of nodes N set on the road is small (that is, when the nodes are sparse), the adjacent nodes N may be extracted as they are.

Further, as shown in FIG. 5 (A), the S-shaped curve has the strictest passage conditions among the composite curves, but when the distance a is set as a constant, a = 30 m.
By so doing, it is possible to reliably determine even a compact S-shaped curve in which two arcs having a radius of curvature R = 30 m are connected.

Further, as shown in FIG. 5 (B), when a bent road such as a crank road exists in the judgment section S ₂ , the node N (singular point) corresponding to the bent point is given priority. The reference nodes N _{1 to} N ₄ . This allows
It is possible to reliably determine a special road shape such as a crank road.

Next, the road shape is determined based on the coordinates of the _four reference nodes N _{1 to} N ₄ (step S4).

First, the angle θ is calculated by the angle calculation means M4.
Calculate ₁ and θ ₂ . That is, as shown in FIG.
Reference node N ₁ (X ₁ , Y ₁ ) and second reference node N
Vector V ₁₂ (X ₁₂ , Y ₁₂ ) connecting with ₂ (X ₂ , Y ₂ ).
And a vector V ₂₃ (X ₂₃ , Y) connecting the second reference node N ₂ (X ₂ , Y ₂ ) and the third reference node N ₃ (X ₃ , Y ₃ ).
₂₃ ) and a vector V connecting the second reference node N ₂ (X ₂ , Y ₂ ) and the fourth reference node N ₄ (X ₄ , Y ₄ ).
₂₄ (X ₂₄ , Y ₂₄ ) is calculated.

[0031] At this time, when the angle formed by the vector V ₁₂ and the vector V ₂₃ and theta _1, from the inner product of the vector V ₁₂ and the vector _{V 23, X 12 · X 23} + Y 12 · Y 23 = (X 12 2 + Y ₁₂ ² ) ^1/2 · (X ₂₃ ² + Y ₂₃ ² ) ^1/2 · cos θ ₁ holds, and cos θ ₁ is obtained from this.

Further, the vector V₁₂And vector V_{twenty four}Success with
Angle θ₂Then, the vector V ₁₂And vector V_{twenty four}
From the dot product of   X₁₂・ X_{twenty four}+ Y₁₂・ Y_{twenty four}         = (X₁₂ ²+ Y₁₂ ²)^1/2・ (X_{twenty four} ²+ Y_{twenty four} ²)^1/2・ Cos θ₂… Holds, and from now on, cos θ₂Is required.

Next, the change rate α is calculated by α = (cos θ ₁ −cos co ₂ ) / cos θ ₁ ...

As is clear from the equation, when the absolute value of the change rate α is small, it corresponds to the case where θ ₁ and θ ₂ are substantially the same and the bend of the road is small (that is, straight road), Conversely, when the absolute value of the rate of change α is large, θ ₁ and θ
₂ is very different and corresponds to a case where the road has a large bend (that is, a crank road or a sharp curve).

The direction of curve of the road is the vector V₁₂as well as
Vector V_{twenty three}Cross product of X₁₂・ Y _{twenty three}-Y₁₂・ X_{twenty three}Positive
It can be judged by the negative.

Thus, as shown in FIGS. 6 and 7, the road shape determination means M5 determines various road shapes according to the value of the change rate α.

If the road shape determined as described above is a curve (step S4), it is further determined whether the curve is an S curve or a crank road (step S4).
5). If the road shape is simply a curve, the advance notice of the curve is displayed on the display means M7 (step S
6) If the road shape is an S-curve or a crank road that is difficult to pass, a notice of the S-curve or crank road is displayed on the display means M7 (step S7).

Next, it is determined whether or not the current vehicle speed V ₀ is appropriate for the determined road shape (step S8), and the current vehicle speed V 0 is set.
_{When 0} is too high for the vehicle speed at which the vehicle can turn the curve ahead, the warning means 12 gives a warning to the occupant (step S9). If the vehicle speed is not decelerated to an appropriate vehicle speed at which the vehicle can surely turn the curve despite the warning (step S10), the vehicle speed adjusting means 13 automatically decelerates (step S11). Then, when the host vehicle passes through the target curve or the vehicle speed V ₀ is decelerated to the proper vehicle speed (step S12), the automatic deceleration is stopped and the process returns to step S1.

On the other hand, if the answer to steps S8 and S10 is NO, and automatic deceleration is not required, it is judged whether or not the processing has been performed for the entire judgment section S ₂ (step S1).
3), the answer is returned to step S3 if not processing has been completed for the entire area of the determination section S ₂ comprising NO, the reference node N ₁ to N ₄ is shifted to the front side repeats the processing described above, As a result, the answer in step S13 is YE.
When S is reached and all processing is completed, the process returns to step S1.

As described above, the coordinates N of the plurality of nodes N
Since the road shape is determined based on the map information consisting of a set of (X, Y), it is not necessary to maintain the infrastructure, which requires high equipment costs and maintenance costs.
The road shape can be determined with the minimum amount of data that can be stored in the M or the IC card.

Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a block diagram corresponding to FIG. 2 of the first embodiment, FIG. 9 is an explanatory diagram of a difference, FIG. 10 is an explanatory diagram showing how to obtain a road shape, and FIG. 11 shows how to obtain a radius of curvature of an arc curve. Explanatory diagram, FIG. 12 is a diagram showing a road shape pattern, FIG. 13 is a diagram showing a road shape pattern, FIG.
FIG. 15 is an explanatory diagram showing a method of determining a non-circular curve, and FIG. 15 is a diagram showing criteria for determining a road shape.

In the second embodiment, the road shape is determined based on _three reference nodes N ₁ , N ₂ and N ₃ which are adjacent to each other. As shown in FIG. 8, the output of the angle calculating means M4 and the distance are calculated. It differs from the first embodiment in that the road shape is determined based on the output of the calculating means M6, and the other configurations are the same as those in the first embodiment.

In the map information of the second embodiment, as a rule for creating data, the distance (hereinafter referred to as a difference) between a line segment connecting adjacent nodes N and a road is set to a predetermined reference value k or less. The position of each node N is determined. That is, FIG.
As shown in (1), in the portion where the radius of curvature of the road is small, the difference is suppressed to the reference value k or less by setting the distance between the adjacent nodes N small.

Extraction of the _three reference nodes N ₁ , N ₂ and N ₃ is performed as follows. That is, the first reference node N ₁ on the most front side among the three reference nodes to be first extracted N _1, N _2, N ₃ is set to the tip of the pre-read interval S _1, nodes adjacent to the front N is the second reference node N ₂
And the node N adjacent to the node in front of it is set as the third reference node N ₃ . These three reference nodes N ₁ ,
N ₂ and N ₃ are sequentially extracted by shifting to the front side.

Next, a method of determining the road shape based on the coordinates of the _three reference nodes N _{1 to} N ₃ will be described. .

First, as shown in FIG. 10, angle calculating means
The first reference node N by M4₁(X ₁, Y₁) And the second group
Quasi node N₂(X₂, Y₂) Vector V connecting with₁₂(X
₁₂, Y₁₂) And the second reference node N₂(X₂, Y₂) And the first
3 reference node N₃(X₃, Y ₃) Vector V connecting with_{twenty three}
(X_{twenty three}, Y_{twenty three}) Is calculated.

That is, from the inner product of the vector V ₁₂ and the vector V ₂₃ , X ₁₂ · X ₂₃ + Y ₁₂ · Y ₂₃ = (X ₁₂ ² + Y ₁₂ ² ) ^1/2 · (X ₂₃ ² + Y ₂₃ ² ) ^1/2・ Cos θ is established, and the angle θ is obtained from this.

Next, the distance calculating means M6 causes the first reference
Code N₁(X₁, Y₁) And the second reference node N₂(X₂，
Y₂) Distance L₁₂And the second reference node N₂(X₂, Y
₂) And the third reference node N₃(X₃, Y₃) Distance L_{twenty three}
And the first reference node N₁(X ₁, Y₁) And the third standard no
De N₃(X₃, Y₃) Distance L₁₃And are calculated.

[0049] L₁₂= (X₁₂ ²+ Y₁₂ ²)^1/2                  … L_{twenty three}= (X_{twenty three} ²+ Y_{twenty three} ²)^1/2                  … L₁₃= (X₁₃ ²+ Y₁₃ ²)^1/2                  … Here, the first reference node N₁(X₁, Y₁) And the third criterion
Node N₃(X₃, Y ₃) And the vector connecting
Le V₁₃(X₁₃, Y₁₃).

As is apparent from FIG. 11, when it is assumed that the _three reference nodes N _{1 to} N ₃ exist on a common arc, that is, when the curve is an arc-shaped curve, L ₁₂ ≈L ₂₃
If so, the radius of curvature R of the arc-shaped curve is obtained by R = L ₁₃ / (2 sin θ) ... And it is possible to determine whether or not the curve can pass based on this radius of curvature R.

As described above, the three reference nodes N ₁ ...
When the angle θ and the distance L ₁₃ are obtained from N _3, the road shape can be determined based on the magnitude of the angle θ and the magnitude of the distance L ₁₃ . That is, as shown in FIG.
Is larger and the distance L ₁₃ is smaller, the radius of curvature of the curve is smaller, and as the angle θ is smaller and the distance L ₁₃ is larger, the radius of curvature of the curve is larger.

By the way, if the three reference nodes N _{1 to} N ₃ exist on a common arc, that is, if the curve is an arc-shaped curve, the road shape can be determined as shown in FIG. However, other than the arc-shaped curve, the curve entrance where the radius of curvature gradually decreases and the curve exit where the radius of curvature gradually increases can be determined as follows.

As shown in FIG. 14, three reference nodes N
Assuming that _{1 to} N ₃ are on a common circular arc, the radius of curvature R is calculated as described above, and the difference between the longer one of the vectors V ₁₂ , V ₂₃ and the circular arc of the radius of curvature R is obtained. If the calculated difference is within the range of the reference value k, it is confirmed that the _three reference nodes N _{1 to} N ₃ are on the arc of the radius of curvature R, but the calculated difference is the reference value k. if beyond the three reference nodes N ₁ to N ₃ is not unlikely be present on the circular arc, three reference node N ₁ non-arcuate curve to N ₃ curvature radius changes gradually (i.e., It is determined to be on the curve entrance or the curve exit).

This will be described in more detail as shown in FIG.
And the first reference node N₁And the second reference node N₂Distance from
L₁₂Is the second reference node N₂And the third reference node N₃Distance from
Distance L _{twenty three}Larger than the first reference node N₁And the second standard
Code N₂Vector V connecting to ₁₂And three reference nodes N₁
~ N₃If the difference with the arc passing through exceeds the reference value k,
Road shape is a curve entrance with a gradually decreasing radius of curvature
Is determined. On the other hand, the distance L_{twenty three}Is the distance L₁₂Greater than
Vector V_{twenty three}The difference between the arc and the arc exceeds the reference value k.
If so, the road shape will be a curve exit with a gradually increasing radius of curvature.
It is determined that

Thus, in FIG. 15, the lower right region where the angle θ is large and the distance L ₁₃ is small corresponds to a sharp curve, intersection, branch road, etc. with a small radius of curvature R, and the angle θ is small and the distance L ₁₃ is small. The lower right region with a large radius corresponds to a gentle curve or straight road with a large radius of curvature R. Further, k _{1 to} k ₄ represent the standard value of the difference (k ₁ > k ₂ > k ₃ > k ₄ ),
If the point determined by the calculated angle θ and the distance L ₁₃ is in the lower left area of the reference value k ₂ , for example, the road shape is an arc curve with a constant radius of curvature, and in the upper right area of the reference value k _2. If so, the road shape is a non-circular curve with a gradually changing radius of curvature.

When the determined road shape is a non-circular curve
The radius of curvature for determining whether the curve can pass or not
Is asked for. That is, obtained in FIG.
The radius of curvature R does not reflect the actual radius of curvature,
Near the exit (ie, the second reference node N₂And the third standard no
De N₃The actual radius of curvature of
Get smaller. Therefore, the first reference node N₁And the second standard
Node N₂The second reference node N on the line segment connecting₂Distance from
L_{twenty three}Position N₁'Takes 3 points N₁′, N₂, N ₃Through
If the radius of curvature R'of the arc
Make sure that the radius of curvature is appropriate for determining whether the curve can pass.
It

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design changes can be made.

[0058]

As described above, according to the first aspect of the present invention, the road shape determination means sets the position on the road.
Vehicle position based on the coordinates of the nodes that make up the map information
If it is determined that the road shape in front of the curve is a curve, the curve is a simple curve or a continuous curve (that is, S
Since it is announced by the notifying means whether it is a curved road or a crank road, the occupant can be surely notified of the road shape in front of the vehicle position .

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of a device of the present invention.

FIG. 2 is a block diagram of a control system

FIG. 3 is a flowchart showing the operation.

FIG. 4 is an explanatory diagram showing how to obtain a road shape.

FIG. 5 is an explanatory diagram of a method of extracting reference coordinate points.

FIG. 6 is a diagram showing a road shape pattern.

FIG. 7 is a diagram showing criteria for determining a road shape.

FIG. 8 is a block diagram corresponding to FIG. 2 according to a second embodiment.

FIG. 9 is an explanatory diagram of a difference

FIG. 10 is an explanatory diagram showing how to obtain a road shape.

FIG. 11 is an explanatory diagram showing how to determine the radius of curvature of an arc curve.

FIG. 12 is a diagram showing a road shape pattern.

FIG. 13 is a diagram showing a road shape pattern.

FIG. 14 is an explanatory diagram showing a method of determining a non-circular curve.

FIG. 15 is a diagram showing criteria for determining a road shape.

[Explanation of symbols] M5 Road shape determination means M7 display means (preliminary means) 12 Warning means 13 Vehicle speed adjustment means

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // G01C 21/00 G01C 21/00 AF term (reference) 2C032 HB03 2F029 AA02 AC04 AC14 AC17 3D044 AA24 AA35 AC26 AC56 AD21 AE14 5H180 AA01 EE15 FF38 FF40 LL08 LL09 LL15

Claims (3)

[Claims] 1. It is determined whether the road shape in front of the vehicle position is a curve based on the map information, and if it is a curve, it is determined whether it is a simple curve, an S-curve or a crank road. When the road shape determination means (M5) and the road shape determination means (M5) determine that the road shape is a curve, the road shape determination means (M5) gives advance notice of whether the curve is a simple curve, an S-shaped curve, or a crank road. A curve advance notice device for a vehicle, comprising: advance notice means (M7). 2. When the road shape determination means (M5) determines that the road shape is a curve, it is determined whether or not the current vehicle speed is excessive with respect to the vehicle speed that can turn the curve, and the current vehicle speed is determined. 2. The vehicle curve advance notice device according to claim 1, wherein the vehicle warning device issues an alarm to the occupant by the alarm means (12) when the vehicle speed is too high to turn a curve. 3. The vehicle speed adjusting means (13) performs automatic deceleration when deceleration is not performed up to a vehicle speed at which the vehicle can turn a curve despite the warning by the warning means (12). The vehicle curve warning device described in 2.