JP4132216B2 - Vehicle travel control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention automatically directed to the vehicle travel control equipment which performs the operation while appropriately maintaining the inter-vehicle distance between the preceding vehicle.
[0002]
[Prior art]
In order to carry out efficient transportation on a road on which many vehicles travel, it is considered that a plurality of vehicles form a vehicle group at least in the same route range and perform platooning. In platooning by a vehicle group, control information such as vehicle speed, acceleration, deceleration, throttle opening, brake operation amount, steering angle, and shift position of the transmission is transmitted from the preceding vehicle to the following vehicle, and the vehicle ahead Rather than recognizing the result of the control as a change in the running state of the vehicle and performing control corresponding to the subsequent vehicle, it is possible to perform control to follow the preceding vehicle without a time delay. Therefore, even if the preceding vehicle suddenly brakes and suddenly brakes, the following vehicle can immediately perform the same sudden braking, and the inter-vehicle distance necessary for preventing the rear-end collision can be shortened. A group of vehicles that perform such platooning is also referred to as a platoon, and can save space required on the road and perform efficient transportation as compared to the case where each vehicle travels alone.
[0003]
In order to form a platone efficiently and safely, it is necessary to appropriately set the inter-vehicle distance derived from the braking characteristics of the vehicle. Prior arts related to setting a safe inter-vehicle distance are disclosed in, for example, Japanese Patent Laid-Open Nos. 7-47864, 8-55300, and 8-268192. In the prior art disclosed in Japanese Patent Application Laid-Open No. 7-47864, a safe inter-vehicle distance with respect to the preceding vehicle is calculated based on the operating state of the engine and the surrounding environment, and the inter-vehicle distance accurately reflects the conditions affecting the braking distance. Is trying to find In the prior art disclosed in Japanese Patent Laid-Open No. 8-55300, it is disclosed to perform control during braking in conformity with environmental conditions and the like when performing platooning with a reduced inter-vehicle distance. In the prior art disclosed in Japanese Patent Laid-Open No. 8-268192, the vehicles forming the vehicle group adjust the control parameters for controlling the inter-vehicle distance according to the traveling environment of the vehicles.
[0004]
[Problems to be solved by the invention]
The braking characteristics of the vehicle are important when the vehicle is traveling alone, but are particularly important when the vehicle group is formed to follow the vehicle. Many factors affect the braking characteristics of a vehicle, and it is difficult to accurately predict even the methods of the three prior arts described above.
[0005]
An object of the present invention grasps accurately braking characteristic of the vehicle, it is to provide a vehicle running control equipment which sets the appropriate distance between vehicles can be controlled automatic traveling of the vehicle.
[0006]
[Means for Solving the Problems]
The present invention provides a vehicle travel control device that controls a travel state of a vehicle while setting a target travel speed and a target inter-vehicle distance and detecting the travel speed of the vehicle and the inter-vehicle distance from a preceding vehicle.
Sudden braking instruction means for instructing sudden braking while the vehicle is running;
In response to a sudden braking instruction to the sudden braking instruction means, sudden braking control means for controlling the vehicle to suddenly brake;
A distance measuring means for measuring a braking distance from the start of the sudden braking by the sudden braking control means until the vehicle stops;
Target setting means for setting the target inter-vehicle distance based on the braking distance measured by the distance measuring means ;
A travel path determination means for determining whether or not the vehicle is traveling on a test travel path provided with a plurality of travel sections having different road surface conditions,
The travel path determination means includes section detection means for detecting which travel section of the test travel path the vehicle is traveling on,
The sudden braking instruction means instructs sudden braking at least once each time a traveling section having a different road surface condition is detected by the section detecting means provided in the traveling road determination means,
The target setting means is a vehicle travel control device that sets a target inter-vehicle distance corresponding to each road surface state .
[0007]
According to the present invention, when sudden braking is instructed while the vehicle is running by the sudden braking instruction means, the sudden braking control means controls to apply sudden braking to the vehicle. The distance measuring means measures a braking distance from the start of sudden braking until the vehicle stops. The target setting means sets the target inter-vehicle distance based on the braking distance measured by the distance measuring means. Since the target inter-vehicle distance is set according to the actually measured braking distance, the inter-vehicle distance when performing control to follow the preceding vehicle is appropriately set, and the road can be used safely and efficiently. .
[0019]
Further , when the travel path determining means determines that the vehicle is traveling on the predetermined travel path, the instructing means instructs the sudden braking, so that the braking characteristics according to the predetermined travel path can be actually grasped. .
[0021]
In addition , when the travel path determination means determines that the predetermined travel path is a test travel path in which a plurality of travel sections having different road surface conditions are provided, the vehicle travels in any travel section of the test travel path by the section detection means. Is detected. The sudden braking instruction means instructs sudden braking at least once every time a traveling section having a different road surface condition is detected, and the target setting means sets a target inter-vehicle distance corresponding to each road surface condition. It is possible to set an appropriate target inter-vehicle distance.
[0022]
Further, in the present invention, the sudden braking instruction means instructs sudden braking in a state where the traveling speed of the vehicle coincides with a predetermined initial braking speed.
[0023]
According to the present invention, when the traveling speed of the vehicle coincides with a predetermined initial braking speed, the sudden braking instruction means instructs sudden braking, so that the braking characteristics at that speed can be grasped and braking at other speeds is performed. It is easy to estimate the characteristics. Furthermore, if the types of speeds at which the braking characteristics are measured as the initial braking speed are increased, the braking characteristics for a wide range of traveling speeds can be easily estimated.
[0024]
In the present invention, the sudden braking control means gives the maximum control amount to the braking mechanism of the vehicle in accordance with the sudden braking instruction from the sudden braking instruction means.
[0025]
According to the present invention, the sudden braking control means gives the maximum control amount to the braking mechanism of the vehicle in accordance with the sudden braking instruction by the sudden braking instruction means. It is possible to set an appropriate target inter-vehicle distance.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a schematic system configuration as a travel control apparatus according to a first embodiment of the present invention. This vehicle travel control device includes components related to automatic steering and automatic speed control for automatically driving a vehicle, and information communication components for forming a vehicle group and performing platooning. included. The CCD camera 1 captures a road surface ahead of the vehicle in the traveling direction, and recognizes a white line that separates road lanes from the obtained image. If automatic steering is performed along the recognized white line, the vehicle can be automatically driven in accordance with the lane. In addition, it is possible to know which lane of the road where a plurality of lanes are provided by white line recognition. Further, when the vehicle is traveling following the vehicle ahead in a platooning or the like, the vehicle in front can enter the field of view of the CCD camera 1 and can be used to monitor its movement.
[0035]
The magnetic sensor 2 detects a magnetic marker embedded in the road surface. The magnetic marker is embedded in a road surface such as an expressway in order to support automatic driving. If a magnetic marker is embedded in the road on which the vehicle travels, automatic driving can be easily performed by detection by the magnetic sensor 2.
[0036]
The steering actuator 3 is provided for automatic steering. The brake actuator 4 is provided for operating the brake mechanism. The throttle actuator 5 is provided to control the amount of fuel supplied to the engine. The optical transceivers 6 and 7 are installed at the front and rear of the vehicle, respectively, and are used to transmit control information between the front vehicle and the rear vehicle. Control information such as vehicle speed, acceleration, deceleration, throttle opening, amount of brake operation, steering angle, and shift position of the transmission required for follow-up control via optical transceivers 6 and 7 is transferred from the preceding vehicle to the following vehicle. Is transmitted as optical data such as infrared rays.
[0037]
Automatic vehicle travel control and platooning are controlled by the vehicle control means 8. The vehicle control means 8 includes a microcomputer and controls automatic driving according to a preset program. The outputs of the CCD camera 1 and the magnetic sensor 2 are input to the vehicle control means 8, and the control output from the vehicle control means 8 is given to the steering actuator 3, the brake actuator 4 and the throttle actuator 5. When performing follow-up running control for platooning, the control amount of the preceding vehicle is received by the optical transceiver 6 provided in the front, and control information is transmitted from the optical transmitter / receiver 7 provided in the rear to the following vehicle.
[0038]
An information communication means 9 is provided to perform inter-vehicle communication and road-vehicle communication with other vehicles traveling on the road on which the vehicle travels and road devices provided in the vicinity of the road. Information received by the information communication means 9 is also given to the vehicle control means 8, and is used for performing control in conformity with the regulation when traffic regulation is performed, for example. In the present embodiment, information related to the test travel path can be received from a road device such as a beacon and provided to the vehicle control means 8 while traveling on a test travel path as will be described later.
[0039]
The current position of the vehicle is detected by a navigation function including a distance / direction sensor 10, a GPS receiver 11, a map data storage unit 12, and a navigation control unit 13. The distance / orientation sensor 10 detects a distance from a vehicle speed pulse and detects a change in direction from a vibration gyro. By accumulating changes in the distance and direction the vehicle has traveled from the reference point whose position is known, the current position relative to the reference position can be obtained. The GPS receiver 11 can detect the absolute current position of the vehicle by receiving radio waves from a plurality of GPS (Global Positioning System) artificial satellites launched on a predetermined orbit of the earth. The map data storage means 12 is detachable from a recording medium such as a large-capacity CD-ROM or DVD, and road map data is recorded on the recording medium. The current position of the vehicle can be corrected in accordance with the map data read from the recording medium. The map data also includes information such as a position where a test traveling path as described later is provided. The navigation control means 13 is configured to include a microcomputer, etc., for setting a travel route of the vehicle according to a preset program, and for the vehicle control means 8 to perform automatic travel control along the set travel route. Provide data. The display / sound output means 14 is provided in the vehicle compartment of the vehicle and displays a map as an image or provides guidance along the travel route by voice so that the driver can drive the vehicle manually. Provide support.
[0040]
FIG. 2 shows a schematic configuration of a test traveling path 20 as a second embodiment of the present invention. The test travel path 20 is provided with a dry path 21, a wet path 22, a water path 23 whose surface is flooded, a snow path 24, and a freezing path 25 as a plurality of travel sections having different road surface conditions. The dry road 21 is a normal dry road surface, and the wet road 22 corresponds to the road surface during light rain. The water channel 23 corresponds to a road surface in which heavy rain is falling. The snow road 24 corresponds to a road surface in a snowy state, and the freezing road 25 corresponds to a road surface in which moisture on the surface is frozen. The distance of each traveling section is set to a length sufficient for testing the braking performance, and the road surface resistance coefficient (μ) is adjusted for each traveling section. The area between each traveling section is separated by a general asphalt section.
[0041]
In front of the test travel path 20, an on-road device 30 that gives instructions to the vehicle is installed in order to adjust the inflow amount of the vehicle to the test travel path 20. Near the starting end of each travel section, road devices 31, 32, 33, 34, and 35 that transmit information indicating the road surface state of the travel section in which the vehicle will travel and information indicating whether or not to enter the vehicle to the vehicle, respectively. Installed. The test traveling path 20 is provided in front of the junction 41 of the exclusive road 40 where, for example, a magnetic nail for performing a platooning is installed. A vehicle that enters the test road 20 in accordance with an instruction from the road device 30 receives information indicating the road surface condition of the next running section transmitted from the road devices 31, 32, 33, 34, and 35, respectively. It memorizes and automatically performs a full brake operation on each travel path to measure the braking distance until the vehicle stops. When the measurement of the braking distance is repeated for each traveling section, the optimum inter-vehicle distance can be calculated from the measured braking distance for each traveling section and stored corresponding to each road surface condition.
[0042]
FIG. 3 shows a procedure for setting the target inter-vehicle distance when the vehicle control means 8 of FIG. 1 passes through each travel section of the test travel path 20 shown in FIG. The procedure starts from step S0, and a sudden braking instruction is issued in step S1. When traveling on the test road 20 of FIG. 2, the output from the information communication means 9 for receiving information from the road devices 31, 32, 33, 34, and 35 is given to the vehicle control means 8 to give a sudden braking instruction. Become. The driver or the like can manually instruct when driving on a general road other than when driving on the test road 20 as shown in FIG. In addition, it is possible to instruct sudden braking every predetermined time by a timer or the like, or to instruct sudden braking automatically every certain traveling distance. Furthermore, an operation for instructing sudden braking can be performed at the time of inspection of the vehicle, for example, by improving the vehicle manufacturing meter or vehicle service. The user can also instruct sudden braking when changing tires.
[0043]
When a sudden braking instruction is issued in step S1, the vehicle control means 8 controls the brake actuator 4 in step S2, and sudden braking is started. Further, the vehicle control means 8 instructs the navigation control means 13 to start the measurement of the braking distance based on the distance / direction sensor 10. In step S3, the navigation control means 13 measures the distance until the vehicle stops based on the output from the distance / orientation sensor 10. The stop of the vehicle is determined, for example, by stopping the derivation of the vehicle speed pulse. In step S4, braking data measured until the vehicle stops is input to the vehicle control means 8 and stored as a braking distance. In step S5, the vehicle control means 8 calculates an inter-vehicle distance suitable for the vehicle based on the braking data. When the inter-vehicle distance is calculated, in step S6, control is performed so that follow-up traveling is performed at the calculated inter-vehicle distance.
[0044]
When the target inter-vehicle distance as shown in FIG. 3 is directly detected, braking is automatically performed after the instruction signal that gives the maximum control amount that can be operated to the brake actuator 4 is output until the vehicle stops. The distance is measured and the target inter-vehicle distance is determined from the measured value. The control amount given to the brake actuator is given by hydraulic pressure, and is automatically adjusted so as not to cause a slip if an anti-skid function is provided.
[0045]
The optimum set value of the target inter-vehicle distance is generally set to a value obtained by adding a certain margin to the braking distance obtained by actual measurement during sudden braking. If the preceding vehicle and the following vehicle have substantially the same braking characteristics when performing the follow-up running in the platooning, the braking equivalent to that of the succeeding vehicle is started before the preceding vehicle starts sudden braking and stops. Since the vehicle travels a distance, the target inter-vehicle distance can be set smaller than the braking distance.
[0046]
FIG. 4 shows a procedure for setting the target inter-vehicle distance in the third embodiment of the present invention. In this embodiment, in each step from step S20 to step S22, an operation equivalent to each step from step S0 to step S2 in FIG. 3 is performed. In step S23, it is determined whether or not the traveling speed from the start of the sudden braking degree has decreased to a predetermined speed. When the traveling speed decreases to the predetermined speed, the traveling distance of the vehicle from the start of sudden braking to the time when the traveling speed decreases to the predetermined speed is given from the navigation control means 13 to the vehicle control means 8 and stored as braking data in step S24. In step S25, a calculation for obtaining the target inter-vehicle distance is performed based on the traveling speed at the start of sudden braking, the above-described predetermined speed, and the measured traveling distance. In step S26, follow-up traveling is performed at the calculated inter-vehicle distance.
[0047]
In this embodiment, it is not necessary to measure the braking distance until the vehicle stops. The braking distance until the vehicle stops based on the traveling distance until the traveling speed decreases from the initial braking speed to the predetermined speed by a full brake operation. It is calculated from the set formula and data table.
[0048]
FIG. 5 shows the relationship between the travel distance from the initial speed of braking at the start of braking of the vehicle to the stop of the vehicle and the change in speed. When sudden braking is started at time t0, the vehicle travels a braking distance of L from the initial braking speed V0 until the vehicle stops and the speed becomes zero. The shape of the curve indicating the change during this period changes depending on the weight of the vehicle, the characteristics of the tires, the road surface condition, etc., but from the travel distance L1 until the travel speed stops to a sufficiently low speed, for example, the speed V1. The braking distance L until the stop can be estimated relatively easily.
[0049]
FIG. 6 shows another procedure for setting the target inter-vehicle distance without stopping the vehicle, as in the second embodiment as the fourth embodiment of the present invention. In this embodiment, operations equivalent to those in steps S0 to S2 in FIG. 3 are performed from step S30 to step S32. In step S33, it is determined whether or not the vehicle has advanced a predetermined distance from the position when the sudden braking is started. In step S34, the travel speed after traveling a predetermined distance from the start of sudden braking is measured by the navigation control means 13, and stored as braking data in the vehicle control means 8 as braking data. In step S35, a calculation for obtaining the target inter-vehicle distance is performed based on the traveling speed when the sudden braking is started, the predetermined distance, and the speed after the predetermined distance has been advanced. In step S36, inter-vehicle distance control is performed based on the obtained target inter-vehicle distance.
[0050]
This embodiment is based on the principle that the braking distance L when the vehicle is stopped is similarly estimated based on the initial speed V0 if the traveling speed V1 in the state where the vehicle has traveled a certain distance L1 is known in FIG.
[0051]
FIG. 7 shows, as a fourth embodiment of the present invention, a control procedure for setting a target inter-vehicle distance by issuing a sudden braking instruction when traveling on a dedicated test travel path. The procedure is started from step S40, and in step S41, it is determined whether or not it is a dedicated test travel path. For example, in the case of the test road 20 shown in FIG. 2, it is possible to determine whether the road is a dedicated test road by receiving information transmitted from the road device 30 provided at the entrance. Further, if the information about the test road is stored in the map data stored in the map data storage means 12 of FIG. 1, the map data is read to determine whether or not the current position test road. Can do. If it is determined in step S41 that the road is a test road, a sudden braking instruction is issued in step S42. When an instruction for sudden braking is given, the target inter-vehicle distance can be set by executing the steps after step S2 in FIG. 3, the step after step S22 in FIG. 4, or the step after step S32 in FIG.
[0052]
FIG. 8 shows a control procedure for setting a target inter-vehicle distance for each travel section on the test travel path 20 as shown in FIG. 2 as a fifth embodiment of the present invention. In step S50, the procedure is started, and in step S51, a travel section is detected based on information transmitted from road devices 31, 32, 33, 34, and 35 provided near the start of each section. Next, the steps from the sudden braking instruction at step S52 to the target inter-vehicle distance calculation at step S56 are the steps from the sudden braking instruction at step S1 to the target inter-vehicle distance calculation at step S5 in the control procedure of FIG. Each is equivalent. In step S57, detection of a further next travel section is determined by reception of information transmitted from the road devices 31 to 35. If the next traveling section is detected, the procedure from step S53 is repeated. If the next travel section is not detected in step S57, it is determined that the test travel path 20 has ended, and in step S58, inter-vehicle distance control is performed according to the target inter-vehicle distance set in accordance with each road surface condition. . Since the target inter-vehicle distance is set according to a plurality of road surface conditions, for example, the image road surface state captured by the CCD camera 1 is determined, and the following driving control is performed using the target inter-vehicle distance that matches the road surface during traveling. I do. The type of road surface condition is manually input by the driver's judgment, or information on the road surface condition in the vicinity of the road is transmitted from the road device provided along the road to the traveling vehicle via the information communication means 9. You can also
[0053]
The procedure from step S53 to step S56 in FIG. 8 can be replaced with the procedure from step S22 to step S25 in FIG. 4 or the procedure from step S32 to step S35 in FIG.
[0054]
FIG. 9 shows, as a sixth embodiment of the present invention, a control procedure for setting a target inter-vehicle distance by performing sudden braking after the traveling speed at the start of sudden braking reaches a constant initial braking speed. The procedure is started from step S90, and a sudden braking instruction is issued in step S91. In step S92, it is determined whether or not the traveling speed matches the braking initial speed. When it does not coincide with the initial braking speed, the speed is adjusted without performing rapid braking. The speed adjustment is performed by controlling the brake actuator 4 in a state where it is not fully braked, or by accelerating with the throttle actuator 5 or decelerating by engine braking. When the traveling speed matches the initial braking speed in step S92, the same operations from step S93 to step S97 and from step S2 to step S6 in FIG. 3 are performed. Each step from step S93 to step S97 can be replaced with each step from step S22 to step S26 in FIG. 4 or each step from step S32 to step S36 in FIG.
[0055]
If a plurality of braking initial speeds are set and the target inter-vehicle distance is set at each initial braking speed, the accuracy of setting the target inter-vehicle distance corresponding to an arbitrary travel speed can be increased.
[0056]
Further, the curve indicating the relationship between the traveling speed and the traveling distance during braking as shown in FIG. 5 changes according to the weight of the vehicle and the characteristics of the tire. Multiple characteristic patterns are stored in advance according to the weight of the vehicle and the characteristics of the tires, and multiple characteristic patterns are selected in accordance with changes in travel distance from braking vehicle speed to stop or speed, or speed decrease to a predetermined distance. If the closest characteristic pattern is selected from the above, the target inter-vehicle distance can be set with higher accuracy for an arbitrary initial braking speed.
[0057]
FIG. 10 shows, as a sixth embodiment of the present invention, not the test road 20 having a plurality of road surface states as shown in FIG. 2 but the test roads in accordance with the worst conditions of the road surface state of the dedicated road 40. The control procedure which sets a road surface state is shown. In step S <b> 151, a road device serving as a center, for example, the road device 30, collects information on road surface information of the dedicated road 40 from road devices provided along the dedicated road 40. The road surface information can be detected based on the reflected wave output by outputting a microwave toward the road surface of the road. In step S152, the worst condition among the collected road surface information is selected. In step S153, the resistance coefficient on the road surface of the test road is set to be similar to the road surface that can occur based on the worst condition. In step S154, an instruction for sudden braking is given to the vehicle entering the test road.
[0058]
In addition, the on-road device 30 provided at the entrance of the test travel path 20 in FIG. 2 can further control the inflow amount of the vehicle entering the test travel path 20 so that the target inter-vehicle distance can be set by suddenly braking safely. It can also be controlled.
[0059]
【The invention's effect】
As described above, according to the present invention, since the braking distance from when the vehicle starts sudden braking until it stops is measured and the target inter-vehicle distance is set, an appropriate target inter-vehicle distance is set according to the braking characteristics of the vehicle. Can be set. When forming a group of vehicles and performing platooning, the target inter-vehicle distance is set appropriately, so that efficient and safe platooning can be performed.
[0066]
Also, since the vehicle can set the target inter-vehicle distance to instruct the rapid braking when traveling the predetermined travel path, to set the target inter-vehicle distance in a stable condition, improve the accuracy of setting be able to.
[0067]
Also, when riding test drive path in which a plurality of travel sections of different road surface condition is provided, it is possible to set the target inter-vehicle distance based on the sudden braking, set the target inter-vehicle distance which is suitable for various road conditions It can be performed.
[0068]
Further, according to the present invention, an appropriate target inter-vehicle distance can be set for a predetermined initial braking speed, and the target inter-vehicle distance for an arbitrary initial braking speed can be easily estimated based on the set value.
[0069]
Further, according to the present invention, it is possible to grasp the braking characteristics at the maximum braking capacity of the vehicle and set an appropriate target inter-vehicle distance.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic system configuration of a vehicle travel control apparatus according to a first embodiment of the present invention.
FIG. 2 is a simplified plan view showing a schematic configuration of a test traveling path 20 as a second embodiment of the present invention.
FIG. 3 is a flowchart showing a control procedure of the vehicle control means of FIG. 1;
FIG. 4 is a flowchart showing a target inter-vehicle distance setting procedure in the third embodiment of the invention.
FIG. 5 is a graph showing an example of a relationship between a traveling speed and a traveling distance during braking of the vehicle.
FIG. 6 is a flowchart showing a procedure for setting a target inter-vehicle distance as a fourth embodiment of the invention.
FIG. 7 is a flowchart showing a procedure of a sudden braking instruction as a fifth embodiment of the invention.
FIG. 8 is a flowchart showing a procedure for setting a target inter-vehicle distance as a sixth embodiment of the invention.
FIG. 9 is a flowchart showing a procedure for setting a target inter-vehicle distance as a seventh embodiment of the invention.
FIG. 10 is a flowchart showing a setting procedure of a test travel path 20 as an eighth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 CCD camera 4 Brake actuator 5 Throttle actuator 6, 7 Optical transmitter / receiver 8 Vehicle control means 9 Information communication means 10 Distance / direction sensor 12 Map data storage means 13 Navigation control means 20 Test traveling path 21 Dry path 22 Wet path 23 Water path 24 Snow road 25 Frozen road 30, 31, 32, 33, 34, 35 Road equipment 40 Dedicated road

Claims (3)

In a vehicle travel control device that sets a target travel speed and a target inter-vehicle distance and controls the travel state of the vehicle while detecting the travel speed of the vehicle and the inter-vehicle distance with the preceding vehicle,
Sudden braking instruction means for instructing sudden braking while the vehicle is running;
In response to a sudden braking instruction to the sudden braking instruction means, sudden braking control means for controlling the vehicle to suddenly brake;
A distance measuring means for measuring a braking distance from the start of the sudden braking by the sudden braking control means until the vehicle stops;
Target setting means for setting the target inter-vehicle distance based on the braking distance measured by the distance measuring means ;
A travel path determination means for determining whether or not the vehicle is traveling on a test travel path provided with a plurality of travel sections having different road surface conditions,
The travel path determination means includes section detection means for detecting which travel section of the test travel path the vehicle is traveling on,
The sudden braking instruction means instructs sudden braking at least once each time a traveling section having a different road surface condition is detected by the section detecting means provided in the traveling road determination means,
The target setting means, vehicle running control apparatus characterized by setting the target inter-vehicle distance corresponding to each road surface state. 2. The vehicle travel control device according to claim 1, wherein the sudden braking instruction means instructs sudden braking in a state where the traveling speed of the vehicle coincides with a predetermined initial braking speed . 3. The vehicle travel control device according to claim 1, wherein the sudden braking control means gives a maximum control amount to the braking mechanism of the vehicle in accordance with a sudden braking instruction from the sudden braking instruction means .

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