JP2009090718A - Safety traveling system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safety traveling system that facilitates avoidance of a collision of vehicles on a road. <P>SOLUTION: A first roadside unit 15 acquires the detection result of a road 13 detected by a road surface state sensor 14. When judged that the road surface μ deteriorates due to freezing, the first roadside unit transmits road surface data, formed from the detection result, to a second roadside unit 16 located at the rear in a traveling direction of the road 13. The roadside unit 16 transmits the received road surface data to a traveling vehicle (one's own vehicle) 17 near it. The one's own vehicle 17 calculates a braking distance of the one's own vehicle 17 from the road surface μ included in the road surface data and a speed of the one's own vehicle and transmits the braking distance together with the road surface data to an immediately preceding vehicle 18 and an immediately following vehicle 19 by inter-vehicle communication. The one's own vehicle 17 acquires a braking distance of the immediately preceding vehicle 18 by a reply from the immediately preceding vehicle 18 so as to calculate a safety distance between the one's own vehicle 17 and the immediately preceding vehicle 18. When an actual distance between the one's own vehicle 17 and the immediately preceding vehicle 18 is less than the calculated safety distance, the one's own vehicle 17 activates a brake actuator to decelerate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a safe traveling system for preventing a subsequent vehicle from colliding with a preceding vehicle during braking.

  As a conventional technique related to a traffic information system, there is one in which an in-vehicle device that has received warning information from a wireless warning board on the road displays warning information such as road surface freezing (see, for example, Patent Document 1). In addition, there is also a conventional technology related to a traffic information system in which various information transmitted from a roadside device is collected at an information center via a communication network, traffic information is formed from the collected information, and distributed to the roadside device via a server. (For example, refer to Patent Document 2).

  According to the prior art described in Patent Document 1, it is possible to give a warning individually to a driver who cannot afford to see a warning display board or the like, and it is possible to reliably call out a danger on the road. . Moreover, in the prior art described in Patent Document 2, traffic information relating to a place spatially separated from the host vehicle scheduled to travel from now on can also be obtained in advance.

  However, on the other hand, the above-described traffic information system according to the prior art cannot know to what extent the traveling danger included in the vehicle has actually obtained the traffic information. For example, even if a traveling vehicle on the road acquires road freezing information, it is not known how much the vehicle on the road is slippery unless the vehicle is actually accelerated, decelerated or steered on the road. Therefore, it has been insufficient for the purpose of avoiding the vehicle from danger in traveling in advance.

On the other hand, there is a conventional technique related to an in-vehicle communication device in which a vehicle traveling on a road classifies road surface conditions into a plurality of types from the detected road noise and transmits the result to another vehicle (for example, (See Patent Document 3). According to this, the vehicle that has received the data relating to the road surface state can grasp the actual road surface state without trying by the own vehicle, and can recognize the degree of danger in traveling in advance.
JP 2001-167384 A JP 2006-202199 A JP-A-9-62980

However, for a user who uses the prior art described in Patent Document 3, the user himself has to think how to operate the vehicle according to the recognized degree of danger. In particular, for a traveling vehicle on a frozen road surface, the inter-vehicle distance between the vehicle located immediately before the own vehicle or the vehicle located immediately after the own vehicle must be provided by the user's experience, and eventually traveled Avoidance from the danger of the vehicle depends largely on the driving skill of the user, and it is necessary for a beginner of the driving operation to perform sufficient training to avoid the danger.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a safe traveling system that can easily avoid a collision of a vehicle on a road.

According to the safe traveling system of claim 1, the braking distance between the own vehicle and the immediately preceding vehicle is calculated based on the road surface data transmitted from the road surface data transmitting means, the own vehicle speed, and the speed of the immediately preceding vehicle. Based on the braking distance of the own vehicle and the braking distance of the immediately preceding vehicle, when the immediately preceding vehicle performs a braking operation, the safe inter-vehicle distance between the own vehicle and the immediately preceding vehicle for stopping the vehicle without colliding with the immediately preceding vehicle is determined. The brake means is operated based on the calculated safe inter-vehicle distance and the actual inter-vehicle distance.
Thereby, based on the received road surface data, a safe inter-vehicle distance can be formed between the own vehicle and the immediately preceding vehicle, and a collision during traveling can be avoided regardless of the driving skill of the user.

  According to the safe driving system of claim 2, the braking distance of the own vehicle and the immediately following vehicle is calculated based on the road surface data transmitted from the road surface data transmitting means, the own vehicle speed, and the speed of the immediately following vehicle. Based on the braking distance of the own vehicle and the braking distance of the immediately following vehicle, when the own vehicle performs a braking operation, the safe inter-vehicle distance between the own vehicle and the immediately following vehicle for stopping the immediately following vehicle without colliding with the own vehicle is determined. Based on the calculated safe inter-vehicle distance and the actual inter-vehicle distance, the vehicle is warned immediately after.

  Thereby, based on the received road surface data, it is possible to warn to provide a safe inter-vehicle distance between the own vehicle and the immediately following vehicle, and avoids a collision during traveling regardless of the driving skill of the user of the immediately following vehicle. be able to.

According to the safe traveling system of the third aspect, the road surface data transmitting means acquires the road surface data and transmits the road surface data to the rear on the road, and the road surface data received from the front roadside device to the nearby traveling vehicle. And a rear roadside machine for transmitting.
Thereby, even if the place where the road surface property is detected and the place where the vehicle receives the road surface data are separated in distance, the road surface data can be reliably transmitted to the vehicle via the front and rear roadside units.

  Hereinafter, based on FIG. 1 thru | or FIG. 4, the safe traveling system by this embodiment is demonstrated. FIG. 1 is a block diagram showing an overall configuration of an in-vehicle safe traveling device 1 that is normally mounted on each vehicle (including a host vehicle, an immediately preceding vehicle, and an immediately following vehicle) and constitutes a part of a safe traveling system. The in-vehicle safe traveling device 1 includes a control device 2, a vehicle speed sensor 3, an acceleration sensor 4, a radar device 5, a brake actuator 6, a display device 7, a speaker 8, a rear vehicle display device 9, and wireless communication with other vehicles. The vehicle-to-vehicle communication device 10 that transmits and receives data (information) and the road-to-vehicle communication device 11 that performs wireless communication with the roadside device are formed.

  The control device 2 is mainly composed of a microcomputer, and the microcomputer includes a CPU, a memory (RAM, ROM, EEPROM, flash memory, etc.), an I / O, and the like. This corresponds to distance calculation means, rear vehicle braking distance calculation means, safe inter-vehicle distance calculation means, and control means. The vehicle speed sensor 3 corresponds to the own vehicle speed detection means, the front vehicle speed detection means, and the rear vehicle speed detection means of the present invention, and is provided on a transmission or a wheel of a vehicle (not shown) to detect the speed of each vehicle.

  The acceleration sensor 4 is a G sensor or the like attached to the vehicle body, and detects the acceleration (deceleration) of the vehicle in order to calculate the friction coefficient of the road surface as will be described later. The radar device 5 is attached to the front end portion and the rear end portion of the vehicle, and each corresponds to the inter-vehicle distance detection means of the present invention. The radar device 5 includes a vehicle (hereinafter referred to as the immediately preceding vehicle) or a vehicle (hereinafter referred to as the immediately following vehicle) that is positioned (runs immediately) in front of the own vehicle or a vehicle that is positioned (traveled) immediately after the own vehicle. The actual distance between the vehicle and the vehicle is detected.

  The brake actuator 6 corresponds to the brake means of the present invention. Based on a signal from the control device 2, the brake actuator 6 drives a hydraulic pump (not shown) to generate a brake pressure in the disc brake so that the vehicle can be operated. Regardless, the braking force is applied to the vehicle. Although the display device 7 is not limited to this, it comprises a color liquid crystal display or the like, and displays a warning or the like to the driver as will be described later. As the speaker 8, a vehicle-mounted audio speaker or a vehicle-mounted navigation device speaker can be used, and a warning or the like is issued to the driver together with the display device 7. The rear vehicle display device 9 corresponds to the rear vehicle warning means of the present invention, and is attached so as to be located inside the rear window 12 of the vehicle. The rear vehicle display device 9 is capable of displaying a text or the like in the horizontal direction by an LED (Light Emitting Diode) or the like, and issues a warning to the vehicle immediately after (see FIG. 4).

  The inter-vehicle communication device 10 performs inter-vehicle communication with the inter-vehicle communication device 10 of another vehicle using, for example, a DSRC (Dedicated Short Range Communication) method using a radio wave of 5.8 GHz, and road data and various Send and receive information. The road-to-vehicle communication device 11 corresponds to the road surface data transmission means of the present invention, performs road-to-vehicle communication with the roadside device described later by the DSRC method, and transmits and receives road surface data and the like.

  Next, based on FIG. 2, the structure of the whole safe traveling system by this embodiment is demonstrated. FIG. 2 is a schematic diagram of the entire safe traveling system according to the present embodiment. As shown in FIG. 2, a road surface state sensor 14 is installed at a point where the road 13 is frequently frozen or snowed so that the road surface property can be detected. The road surface state sensor 14 corresponding to the road surface state detection means of the present invention detects road surface properties (states) such as rain, freezing, and snowfall on the road surface. Based on the detection result by the road surface state sensor 14, it is possible to estimate the coefficient of friction (μ) between the tires on the road surface.

  There are various methods for detecting the road surface property. For example, there is a method in which a road surface is photographed with a camera and a reflected light from the road surface is spectrally analyzed to analyze a substance on the road surface and its state. If it is determined from the image that there is no moisture on the road surface, it is determined that the vehicle is in a dry state. If it is determined that water is present in a solid state, it is determined that the road surface is in a frozen state. Another method is to embed a sensor in the road surface, detect whether the road surface is in a liquid state or a solid state from the conductivity of the road surface, and determine that it is in a frozen state if it is in a solid state. In the present embodiment, the detection method of the sensor that detects the road surface condition is not particularly limited.

  The first roadside machine 15 and the second roadside machine 16 are installed on the side edges of the road so as to be separated from each other by a predetermined distance, and each includes a roadside transmission unit, a roadside reception unit, and a roadside control unit (both not shown). ing. The 1st roadside machine 15 and the 2nd roadside machine 16 correspond to the road surface data transmission means of this invention, and also the 1st roadside machine 15 corresponds to the front roadside machine of this invention. Further, the second roadside machine 16 corresponds to the rear roadside machine of the present invention, and is located behind the first roadside machine 15 in the vehicle traveling direction on the road 13. The roadside control unit is formed by a CPU, a memory such as a ROM and a RAM, and various interface circuits, and controls the roadside transmission unit and the roadside reception unit. The roadside transmitter and the roadside receiver are connected to the road-to-vehicle communicator 11 of the vehicle traveling on the road 13, and in addition to the roadside machine, for example, the road by the DSRC method using 5.8 GHz radio waves. Inter-vehicle communication and roadside communication are performed. The communication between the first roadside machine 15 and the second roadside machine 16 may be performed by wired communication.

  After the roadside receiving unit of the first roadside machine 15 acquires the detection result from the road surface state sensor 14 by wireless communication or wired communication, the roadside control unit of the first roadside machine 15 uses the conventional method based on the acquired detection result. To form road surface data including μ on the road surface. Further, the roadside control unit of the first roadside machine 15 determines whether or not the formed road surface data satisfies a predetermined condition. That is, when it is determined that the road surface is frozen or snowing on the road surface and μ of the road surface is lower than a predetermined value, the road surface data is wirelessly transmitted from the road-side transmission unit of the first roadside device 15 or It is sent to the second roadside device 16 located behind the road 13 by wired communication. After the roadside data is received by the roadside receiving unit, the second roadside device 16 wirelessly transmits the roadside data from the roadside transmitting unit toward the nearby vehicle 17 traveling on the road 13.

  Transmission of road surface data from the second roadside device 16 to the traveling vehicle 17 is performed at predetermined time intervals regardless of whether or not there is a traveling vehicle on the road 13 when the second roadside device 16 acquires the road surface data. Or may be performed only when the second roadside machine 16 detects the presence of the vehicle 17 traveling in the vicinity. In addition, in the road side control part of the 1st roadside machine 15, when it determines with the road surface data acquired from the road surface state sensor 14 not having reduced (micro | micron | mu) of the road surface from the predetermined value, road surface data is sent to the 2nd roadside machine 16. The road surface data is not transmitted to the traveling vehicle 17 on the road 13 as a matter of course.

  Next, based on FIG. 2 and FIG. 3, the control method by the control apparatus 2 of the own vehicle for forming the safe inter-vehicle distance between the own vehicle and the immediately preceding vehicle or the immediately following vehicle according to the present embodiment will be described. As described above, when road surface data is transmitted from the second roadside device 16 to the nearby vehicle 17 (hereinafter referred to as the own vehicle 17) traveling on the road 13 from the second roadside device 16 (in FIG. 3). Step S301), road surface data is received by the inter-vehicle communication device 11 of the own vehicle 17. The control device 2 of the host vehicle 17 calculates the braking distance S1 of the host vehicle 17 (the distance until the host vehicle 17 stops on the road 13) based on the acquired road surface data (step S302). If it is not determined in step S301 that road surface data has been transmitted from the second roadside device 16 to the host vehicle 17, the present control flow ends.

The braking distance S1 of the host vehicle 17 is calculated from the road surface μ included in the road surface data and the speed of the host vehicle 17 detected by the vehicle speed sensor 3 by a well-known formula: S1 = {speed of the host vehicle 17 (km / hour)} ² It is obtained by × 1 / (μ × C). Here, C in the equation is a constant and normally takes a value of 254 to 259, but it is desirable to set C = 254 if the braking distance S1 in consideration of safety is obtained. When the braking distance S1 of the own vehicle 17 is calculated in the control device 2 of the own vehicle 17, the road surface μ decreases in front of the road 13 with respect to the immediately preceding vehicle 18 and the immediately following vehicle 19 from the inter-vehicle communication device 10 of the own vehicle 17. And the road surface data and the calculated braking distance S1 of the vehicle 17 are transmitted (step S303).
The control device 2 of the immediately preceding vehicle 18 and the immediately following vehicle 19 receives the road surface data from the own vehicle 17, and then detects the road surface μ included in the road surface data and the immediately preceding vehicle 18 detected by the vehicle speed sensor 3 of the immediately preceding vehicle 18 and the immediately following vehicle 19. The braking distances S2 and S3 of the immediately preceding vehicle 18 and the immediately following vehicle 19 are calculated from the speed of the immediately following vehicle 19 by the same method as that for the own vehicle 17, respectively.

  When there is a reply from the immediately preceding vehicle 18 to the own vehicle 17 for the transmission of the road surface data to the immediately preceding vehicle 18 and the braking distance S1 of the own vehicle 17 (step S304), the immediately preceding vehicle from the reply information of the immediately preceding vehicle 18 18 braking distances S2 are obtained (step S305). If there is no reply from the immediately preceding vehicle 18 to the host vehicle 17 due to the reason that the immediately preceding vehicle 18 is not equipped with the in-vehicle safety traveling device 1 (step S304), the control device 2 of the host vehicle 17 determines the The braking distance S2 is set to 0 (step S306). Note that transmission / reception between the own vehicle 17 and the immediately preceding vehicle 18 is desirably performed by giving both ID numbers to each other for identification.

  The own vehicle 17 that has received the braking distance S2 from the immediately preceding vehicle 18 or set the braking distance S2 to 0 is based on the braking distance S1 of the own vehicle 17 and the braking distance S2 of the immediately preceding vehicle 18, and A safe inter-vehicle distance D1 from the vehicle 18 is calculated (step S307). The safe inter-vehicle distance D1 between the host vehicle 17 and the immediately preceding vehicle 18 is the vehicle's own distance on which the host vehicle 17 stops without colliding with the immediately preceding vehicle 18 when the preceding vehicle 18 performs a braking operation on the road 13. This is the distance before the braking force is applied between the vehicle 17 and the immediately preceding vehicle 18.

The safe inter-vehicle distance D1 between the host vehicle 17 and the immediately preceding vehicle 18 is calculated based on the following equation.
(When the braking distance S1 of the host vehicle 17> the braking distance S2 of the immediately preceding vehicle 18)
Safety inter-vehicle distance D1 = braking distance S1 of own vehicle 17—braking distance S2 + M of preceding vehicle 18
(When braking distance S1 of own vehicle 17 <braking distance S2 of immediately preceding vehicle 18)
Safety inter-vehicle distance D1 = M
Here, M in both types is a margin distance (a so-called free running distance, a distance that the vehicle travels from when the driver recognizes the necessity of braking until when the brake operation is actually performed). Therefore, they are the same value and are obtained by the following formula.

M = speed of own vehicle 17 × k (k is a constant)
Here, the speed of the host vehicle 17 may be a relative speed of the host vehicle 17 with respect to the speed of the immediately preceding vehicle 18. However, if a safe inter-vehicle distance that is considered more safely is obtained, the absolute speed of the host vehicle 17 is used. Is desirable.
Further, as described above, when there is no reply from the immediately preceding vehicle 18 in step S304 due to the fact that the immediately preceding vehicle 18 is not equipped with the in-vehicle safe traveling device 1, the braking distance S2 of the immediately preceding vehicle 18 is set to 0. The safe inter-vehicle distance D1 is calculated by the above equation.

Next, the actual inter-vehicle distance between the own vehicle 17 and the immediately preceding vehicle 18 detected by the radar device 5 attached to the front end of the own vehicle 17 is calculated by the control device 2. It is determined whether or not the distance between the vehicle and the safety distance is 18 or more (step S308). When the actual inter-vehicle distance between the host vehicle 17 and the immediately preceding vehicle 18 is less than the calculated safe inter-vehicle distance D1, the control device 2 operates the brake actuator 6 so that the actual inter-vehicle distance is calculated. A braking force is applied to the host vehicle 17 until the distance becomes equal to or greater than the distance D1 (step S309). Thereafter, the display device 7 or the speaker 8 or both notifies the driver of the vehicle 17 that the brake actuator 6 has been operated in order to increase the inter-vehicle distance between the vehicle 17 and the immediately preceding vehicle 18. (Step S310). If it is determined in step S308 that the actual inter-vehicle distance between the host vehicle 17 and the immediately preceding vehicle 18 is equal to or greater than the calculated safe inter-vehicle distance D1, the process proceeds to step S311.
On the other hand, the vehicle 19 immediately after receiving the braking distance S1 from the own vehicle 17 and the vehicle 17 immediately after the vehicle 17 in the same manner as described above based on the braking distance S1 of the own vehicle 17 and the braking distance S3 of the immediately following vehicle 19. A safe inter-vehicle distance D2 with the vehicle 19 is calculated.

  In step S311, it is determined whether or not there is a reply from the immediately following vehicle 19 to the own vehicle 17 with respect to the transmission of the road surface data to the immediately following vehicle 19 and the braking distance S1 of the own vehicle 17. When it is determined that there is a reply from the vehicle 19 immediately after to the own vehicle 17, the own vehicle 17 determines the braking distance S3 of the immediately following vehicle 19 and the calculated own vehicle 17 and the immediately following vehicle 19 from the reply information of the immediately following vehicle 19. A safe inter-vehicle distance D2 is obtained (step S312). Note that transmission / reception between the own vehicle 17 and the vehicle 19 immediately after is preferably performed by assigning both ID numbers to each other for identification.

  If it is determined in step S311 that there is no reply from the immediately following vehicle 19 to the own vehicle 17 due to the fact that the immediately following vehicle 19 is not mounted with the in-vehicle safe traveling device 1, the control device 2 of the own vehicle 17 immediately follows. A braking distance S3 of the vehicle 19 is set (step S313). The own vehicle 17 detects the relative speed of the immediately following vehicle 19 with respect to the own vehicle 17 by the radar device 5 attached to the rear end thereof, and determines the speed of the own vehicle 17 detected by the vehicle speed sensor 3 relative to the immediately following vehicle 19. By subtracting from the speed, the speed of the immediately following vehicle 19 (absolute speed with respect to the road 13) is detected, and the braking distance S3 of the immediately following vehicle 19 is calculated from the road surface μ included in the road surface data and the absolute speed of the immediately following vehicle 19. Thereafter, based on the calculated braking distance S1 of the own vehicle 17 and the braking distance S3 of the immediately following vehicle 19, a safe inter-vehicle distance D2 between the own vehicle 17 and the immediately following vehicle 19 is calculated (step S314). The safe inter-vehicle distance D <b> 2 between the host vehicle 17 and the immediately following vehicle 19 is that the vehicle 19 stops immediately after it does not collide with the host vehicle 17 when the host vehicle 17 performs a braking operation on the road 13. This is the distance before the braking force is applied between the vehicle 17 and the immediately preceding vehicle 18.

  Next, the actual inter-vehicle distance between the own vehicle 17 and the immediately following vehicle 19 detected by the radar device 5 attached to the rear end of the own vehicle 17 is acquired from the immediately following vehicle 19 by inter-vehicle communication. It is determined whether the distance between the vehicle and the vehicle 19 is equal to or greater than the distance D2 between the safe vehicle and the distance D2 calculated by the control device 2 of the host vehicle 17 (step S315). When the actual inter-vehicle distance between the own vehicle 17 and the immediately following vehicle 19 is less than the safe inter-vehicle distance D2 between the own vehicle 17 and the immediately following vehicle 19, the control device 2 of the own vehicle 17 transmits the immediately following vehicle by inter-vehicle communication. A warning is given to the vehicle 19 so as to decelerate and increase the inter-vehicle distance (step S316). Thereafter, the above-described rear vehicle warning device 9 displays, for example, “please leave a distance between vehicles” and prompts the vehicle 19 to decelerate immediately (step S317). Further, when it is determined in step S315 that the actual inter-vehicle distance between the host vehicle 17 and the immediately following vehicle 19 is equal to or greater than the calculated safe inter-vehicle distance D2, this control flow ends.

According to this embodiment, based on the road surface data transmitted from the second roadside machine 16, the speed of the own vehicle 17, and the speed of the immediately preceding vehicle 18, the braking distances S1 and S2 of the own vehicle 17 and the immediately preceding vehicle 18 are calculated. Based on the calculated braking distance S1 of the own vehicle 17 and the braking distance S2 of the immediately preceding vehicle 18, when the immediately preceding vehicle 18 performs a braking operation, the own vehicle 17 stops without colliding with the immediately preceding vehicle 18. A safe inter-vehicle distance D1 between the vehicle 17 and the immediately preceding vehicle 18 is calculated, and the brake actuator 6 of the host vehicle 17 is operated based on the calculated safe inter-vehicle distance D1 and the actual inter-vehicle distance.
Thereby, based on the received road surface data, a safe inter-vehicle distance D1 can be formed between the own vehicle 17 and the immediately preceding vehicle 18, and a collision during traveling can be avoided regardless of the driving skill of the user. .

Further, based on the road surface data transmitted from the second roadside device 16, the speed of the own vehicle 17, and the speed of the immediately following vehicle 19, the braking distances S1 and S3 of the own vehicle 17 and the immediately following vehicle 19 are calculated, and the calculated own vehicle is calculated. Based on the braking distance S1 of the vehicle 17 and the braking distance S3 of the immediately following vehicle 19, when the own vehicle 17 performs a braking operation, the immediately following vehicle 19 stops without colliding with the own vehicle 17 and the immediately following vehicle 19 A safe inter-vehicle distance D2 is calculated, and the vehicle 19 is warned immediately after the calculated safe inter-vehicle distance D2 and the actual inter-vehicle distance.
Thereby, based on the received road surface data, it is possible to warn that a safe inter-vehicle distance D2 is provided between the own vehicle 17 and the vehicle 19 immediately after the vehicle, and the vehicle 19 can be used regardless of the driving skill of the user of the vehicle 19 immediately after traveling. Collisions can be avoided.

Also, a first roadside device 15 that acquires road surface data and transmits it to the rear on the road 13, and a second roadside device 16 that transmits road surface data received from the first roadside device 15 to the nearby traveling vehicle 17; Is installed.
Thereby, even if the place where the road surface property is detected and the place where the vehicle 17 receives the road surface data are separated in distance, the road surface data is reliably transmitted to the vehicle 17 via the front and rear roadside units 15 and 16. it can.
Further, since the road surface μ is calculated based on the detection result of the road surface state sensor 14 provided on the road 13, no vehicle braking operation is required on the road 13 for calculating the road surface μ. It is possible to make the system compatible with the situation.

<Other embodiments>
The present invention is not limited to the above-described embodiments, and can be modified or expanded as follows.
Instead of using the road surface state sensor 14, the road surface μ may be detected from the braking state of the traveling vehicle on the road. As shown in FIG. 2, when a traveling vehicle 20 equipped with ABS (Antilock Brake System) performs a braking operation at a freezing point on the road 13, the braking force is exerted on the vehicle 20 by the maximum frictional force of the road surface by the action of the ABS. It is thought to work. Therefore, the deceleration of the vehicle 20 generated at this time is detected by the acceleration sensor 4, and the braking force (maximum frictional force received from the road surface) is calculated from this and the vehicle weight of the vehicle 20. The road surface μ may be obtained from the calculated braking force of the vehicle 20 and the load applied to each wheel.

In addition, when calculating the braking distance of each vehicle, it is even more accurate if the tire type of each vehicle (for example, whether it is a normal tire or a studless tire), tire wear, tire pressure, etc. are taken into account. A value can be determined.
Further, the transmission of road surface data to the vehicle 17 may be performed by inter-vehicle communication instead of the inter-road communication by the roadside devices 15 and 16. In this case, in FIG. 2, when it is determined that the road surface μ is lowered due to the braking state of the traveling vehicle 20, the vehicles traveling between the traveling vehicle 20 and the immediately preceding vehicle 18 are passed through one by one. The road surface data may be transmitted from the traveling vehicle 20 to the host vehicle 17 by inter-vehicle communication.

Further, when the safe inter-vehicle distance D2 between the own vehicle 17 and the immediately following vehicle 19 is calculated, the own vehicle 17 acquires the braking distance S3 of the immediately following vehicle 19 from the immediately following vehicle 19 by inter-vehicle communication, and this and the own vehicle 17 Based on the braking distance S1, the controller 2 of the host vehicle 17 may calculate the safe inter-vehicle distance D2.
Further, when there is no reply from the immediately following vehicle 19 for the transmission of the road surface data to the vehicle 19 immediately after the own vehicle 17, the vehicle 17 considers the speed of the immediately following vehicle 19, the road surface μ, etc. Set as the braking distance S3 of the vehicle 19 immediately after, and calculate the safe inter-vehicle distance D2 between the vehicle 17 and the immediately following vehicle 19 based on the braking distance S1 of the vehicle 17, the braking distance S3 of the vehicle 19 and the road surface μ. May be.

The block diagram which shows the structure of the vehicle-mounted safe traveling apparatus which forms the safe traveling system by this embodiment. Overall view for explaining the safe driving system Flow chart showing a control method for forming a safe inter-vehicle distance Rear view of the vehicle showing the mounting state of the display device for the rear vehicle

Explanation of symbols

  In the drawings, reference numeral 1 denotes an in-vehicle safety traveling device, 2 a control device (own vehicle braking distance calculation means, front vehicle braking distance calculation means, rear vehicle braking distance calculation means, safe inter-vehicle distance calculation means, control means), and 3 a vehicle speed sensor. (Self-vehicle speed detection means, front-vehicle speed detection means, rear-vehicle speed detection means), 5 is a radar device (inter-vehicle distance detection means), 6 is a brake actuator (brake means), 9 is a rear-vehicle display device (rear vehicle) Warning means), 10 is an inter-vehicle communication device, 11 is a road-to-vehicle communication device (road surface data transmission means), 13 is a road, 14 is a road surface state sensor (road surface state detection means), and 15 is a first road side device (forward road side device). , 16 is the second roadside machine (rear roadside machine), 17 is the own vehicle, 18 is the immediately preceding vehicle, and 19 is the immediately following vehicle.

Claims (3)

Road surface condition detecting means for detecting road surface properties;
Road surface data transmitting means for acquiring the detection result by the road surface state detecting means and transmitting road surface data to a vehicle traveling behind on the road;
Own vehicle speed detecting means for detecting the speed of the own vehicle;
Front vehicle speed detecting means for detecting the speed of the vehicle traveling immediately before the own vehicle;
Own vehicle braking distance calculation means for calculating the braking distance of the own vehicle based on the road surface data transmitted from the road surface data transmission means and the own vehicle speed detected by the own vehicle speed detection means;
Front vehicle braking distance calculating means for calculating the braking distance of the immediately preceding vehicle based on the road surface data transmitted from the road surface data transmitting means and the speed of the immediately preceding vehicle detected by the preceding vehicle speed detecting means;
Based on the braking distance of the own vehicle calculated by the own vehicle braking distance calculating means and the braking distance of the immediately preceding vehicle calculated by the preceding vehicle braking distance calculating means, when the immediately preceding vehicle performs a braking operation, the own vehicle A safe inter-vehicle distance calculating means for calculating a safe inter-vehicle distance between the host vehicle and the preceding vehicle for stopping without colliding with,
An inter-vehicle distance detecting means for detecting an actual inter-vehicle distance between the host vehicle and the immediately preceding vehicle;
Braking means for applying braking force to the vehicle independently of the driver's operation;
Based on the safe inter-vehicle distance between the host vehicle and the preceding vehicle calculated by the safe inter-vehicle distance calculation means, and the actual inter-vehicle distance between the host vehicle and the immediately preceding vehicle detected by the inter-vehicle distance detection means, A safe traveling system comprising control means for operating the brake means. Rear vehicle speed detecting means for detecting the speed of the vehicle traveling immediately after the host vehicle;
Rear vehicle braking distance calculating means for calculating the braking distance of the immediately following vehicle based on the road surface data transmitted from the road surface data transmitting means and the speed of the immediately following vehicle detected by the rear vehicle speed detecting means;
Immediately after that, equipped with a rear vehicle warning means for issuing a warning to the vehicle,
The safety inter-vehicle distance calculating means is operated by the own vehicle based on the braking distance of the own vehicle calculated by the own-vehicle braking distance calculating means and the braking distance of the immediately following vehicle calculated by the rear-vehicle braking distance calculating means. Sometimes, a safe inter-vehicle distance between the own vehicle and the immediately following vehicle for the vehicle immediately after it stops without colliding with the own vehicle is calculated, and the inter-vehicle distance detection means detects the actual distance between the own vehicle and the immediately following vehicle. The inter-vehicle distance is detected, and the control means calculates the safe inter-vehicle distance between the own vehicle and the immediately following vehicle calculated by the safe inter-vehicle distance calculating means, and the own vehicle and the immediately following vehicle detected by the inter-vehicle distance detecting means. 2. The safe traveling system according to claim 1, wherein the rear vehicle warning means is operated to warn the vehicle immediately after the actual vehicle distance between the two.   The road surface data transmitting means includes a front roadside machine that acquires road surface data and transmits the road data rearward on the road, and a rear roadside machine that transmits road surface data received from the front roadside machine to nearby traveling vehicles. The safe traveling system according to claim 1 or 2, wherein

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