JP2012081924A - Driving support device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving support device for improving a traffic flow in a congested section.SOLUTION: The driving support device performs driving support in the congested section and includes: an average speed acquisition means for acquiring average speed in the congested section; an upper limit speed setting means for setting speed higher than the average speed in the congested section acquired by the average speed acquisition means as upper limit speed in the congested section; and a driving support means for performing driving support (for example, speed control and information provision) based on the upper limit speed in the congested section set by the upper limit speed setting means, and further includes a travel proportion acquisition means for acquiring proportion by which a vehicle mounted with a driving support device is traveling in the congestion section. Preferably, the upper limit speed setting means sets upper limit speed according to the travel proportion acquired by the travel proportion acquisition means.

Description

  The present invention relates to a driving support device that performs driving support in a traffic jam section.

  In a traffic jam section, each vehicle repeatedly decelerates, stops, and accelerates (starts). If the vehicle stops in a traffic jam, the delay in starting from the stop to the acceleration causes a further traffic jam in the following vehicle and delays the cancellation of the traffic jam. In the follow-up running control device described in Patent Document 1, when the inter-vehicle distance with the preceding vehicle is opened more than a predetermined value during follow-up running in a traffic jam, the vehicle immediately shifts to constant speed without releasing the follow-up running, Suppresses unnecessary acceleration / deceleration at the time.

Japanese Patent Laid-Open No. 10-44826

  In the above tracking control device, in order to suppress useless acceleration / deceleration during a traffic jam, the vehicle shifts to a constant speed when the inter-vehicle distance from the preceding vehicle is more than a predetermined value during the following running in the traffic jam section. If the vehicle is not driven at a constant speed, the average speed in the traffic jam section will not increase, and it will not lead to improved traffic flow (congestion elimination).

  Then, this invention makes it a subject to provide the driving assistance apparatus which improves the traffic flow of a congestion area.

  The driving support device according to the present invention is a driving support device that performs driving support in a traffic jam section, and includes an average speed acquisition unit that acquires an average speed of the traffic jam section, and an average speed of the traffic jam section acquired by the average speed acquisition unit. An upper limit speed setting unit that sets a high speed as an upper limit speed in a traffic jam section, and a driving support unit that performs driving support based on the upper limit speed in the traffic jam section set by the upper limit speed setting unit are provided.

  In this driving support device, the average speed of the traffic jam section is acquired by the average speed acquisition means. In the driving support device, the upper limit speed setting means sets a speed higher than the average speed in the traffic jam section as the upper speed limit in the traffic jam section. In the driving support device, driving support is performed by the driving support means based on the upper limit speed in the traffic jam section (for example, speed control by intervention control, provision of information by display or voice). If the previous vehicle accelerates in a traffic jam section, stop acceleration at the upper limit speed (stop following the previous vehicle), and run at a constant speed at the upper limit speed, you can leave a gap between the previous vehicle and traffic jam The acceleration inside can also be suppressed. When the immediately preceding vehicle decelerates after accelerating, the deceleration can be suppressed while gradually closing the sufficiently secured space, so that the vehicle can travel without stopping as much as possible. As a result, the number of stops of the own vehicle and the following vehicle is reduced, the number of start delays when accelerating when the vehicle is stopped can be reduced, and the travel time in a traffic jam section can be shortened. Thus, according to the driving support device, by performing driving support with the upper limit of the speed higher than the average speed in the traffic jam section as an upper limit, the number of stops in the traffic jam section can be reduced and the traffic flow in the traffic jam section can be improved. When the upper limit speed is set to the average speed, the average speed in the traffic jam section is not recovered and the traffic jam is not eliminated.

  In the driving support apparatus of the present invention, the driving support apparatus includes a travel ratio acquisition unit that acquires a ratio of a vehicle on which the driving support apparatus is traveling in a traffic jam section, and the upper limit speed setting unit is a travel ratio acquired by the travel ratio acquisition unit. It is preferable to set the upper limit speed according to the above.

  In this driving support apparatus, the ratio of traveling of the vehicle equipped with the driving support apparatus to all the vehicles traveling in the traffic jam section is acquired by the driving ratio acquisition means. In the driving assistance device, the upper limit speed is set by the upper limit speed setting means in accordance with the traveling ratio of the vehicle. The higher the travel ratio of vehicles equipped with this driving support device, the more vehicles will travel at an upper limit speed that is higher than the average speed in the traffic jam section. By setting the upper speed limit to a higher speed, the average speed in the traffic jam section Will rise more. Thus, in the driving assistance device, the traffic flow in the traffic jam section can be further improved by setting the upper limit speed according to the traveling ratio of the vehicle on which the driving assistance device is mounted.

  According to the present invention, by performing driving support with an upper limit of speed higher than the average speed in a traffic jam section, the number of stops in the traffic jam section can be reduced, and the traffic flow in the traffic jam section can be improved.

It is a block diagram of the ACC system which concerns on this Embodiment. It is a schematic diagram for demonstrating the means to acquire the information of the ACC system of FIG. It is an example of the speed change of the vehicle in a traffic congestion area for demonstrating the effect | action in the traffic congestion area by the ACC system of FIG. It is a flowchart which shows the flow of the main process of ECU in the ACC system of FIG. It is a flowchart which shows the flow of the upper limit speed setting process of ECU in the ACC system of FIG. It is an example of an upper limit speed map. It is an analysis result of the simulation experiment which actually used the ACC system loading vehicle concerning this embodiment. It is the speed change of each vehicle in the simulation experiment which actually used the ACC system loading vehicle concerning this embodiment, and the inter-vehicle distance change of the own vehicle and the preceding vehicle.

  Embodiments of a driving assistance apparatus according to the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected about the element which is the same or it corresponds in each figure, and the overlapping description is abbreviate | omitted.

  In the present embodiment, the driving support apparatus according to the present invention is applied to an ACC [Adaptive Cruise Control] system mounted on a vehicle. The ACC system according to the present embodiment performs follow-up traveling control for speed control so that the inter-vehicle distance with the immediately preceding vehicle becomes the target inter-vehicle distance when the immediately preceding vehicle exists in front of the host vehicle, and the immediately preceding vehicle does not exist. In this case, steady-speed traveling control is performed in which the speed of the host vehicle is controlled so as to become the target speed.

  Examples of the target speed during normal driving include a vehicle speed set by an operation by the driver and a vehicle speed when the driver activates the ACC system. In particular, the target speed at the time of traffic jam is set as the upper limit speed in the ACC system. In addition, as the target inter-vehicle distance, for example, there is an inter-vehicle distance preset for each vehicle speed (a shorter inter-vehicle distance as the vehicle speed is lower). In the follow-up running control, the control may be performed not by the inter-vehicle distance but by the inter-vehicle time (= inter-vehicle distance / vehicle speed).

  The ACC system 1 according to the present embodiment will be described with reference to FIGS. FIG. 1 is a configuration diagram of an ACC system according to the present embodiment. FIG. 2 is a schematic diagram for explaining means for obtaining information of the ACC system of FIG. FIG. 3 is an example of a speed change of the vehicle in the traffic jam section for explaining the operation in the traffic jam section by the ACC system of FIG.

  The ACC system 1 has a normal travel mode in which the same control as the conventional ACC system is performed and a traffic jam section travel mode in which special control is performed in the traffic jam section. In the traffic zone running mode (especially when the previous vehicle is detected), the ACC system 1 sets an upper limit speed that is higher than the average speed of the traffic zone, and when the immediately preceding vehicle is less than the upper limit speed, it follows the vehicle. If the immediately preceding vehicle exceeds the upper limit speed, steady speed running control at the upper limit speed is performed. For this purpose, the ACC system 1 includes an autonomous sensor 10, a wide-area road-to-vehicle communication apparatus 11, a narrow-area road-to-vehicle communication apparatus 12, an inter-vehicle communication apparatus 13, a throttle actuator 20, a brake actuator 21, and an ECU [Electronic Control Unit] 30. It has.

  In the present embodiment, the autonomous sensor 10, the wide-area road-to-vehicle communication apparatus 11, the narrow-area road-to-vehicle communication apparatus 12, and the inter-vehicle communication apparatus 13 correspond to the average speed acquisition means described in the claims. The road-to-vehicle communication device 12 and the vehicle-to-vehicle communication device 13 correspond to the travel ratio acquisition means described in the claims, and the processing in the ECU 30 corresponds to the upper limit speed setting means described in the claims. The throttle actuator 20 and the brake actuator 21 correspond to the driving support means described in the claims.

  The autonomous sensor 10 is a sensor that detects own vehicle information and immediately preceding vehicle information in a vehicle. The own vehicle information is, for example, the speed and position of the own vehicle. Sensors that detect the vehicle information are, for example, a vehicle speed sensor and a GPS sensor. The immediately preceding vehicle information is, for example, radar information (a scan angle in the horizontal direction, transmission time, reception time, reception intensity, etc. for each reflection point (each detection point)) at a radar sensor. From this radar information, the ECU 30 can determine the presence or absence of the immediately preceding vehicle and calculate the relative distance and relative speed with the immediately preceding vehicle. The sensor that detects the immediately preceding vehicle information is, for example, a radar sensor that uses millimeter waves, laser light, or the like. When the autonomous sensor 10 detects the own vehicle information and the immediately preceding vehicle information, the autonomous sensor 10 outputs the detected own vehicle information and immediately preceding vehicle information to the ECU 30. In the example shown in FIG. 2, in the own vehicle MV equipped with the ACC system 1, the speed and the like of the own vehicle MV are detected by the autonomous sensor 10 and the inter-vehicle distance and speed of the immediately preceding vehicle PV are detected. The immediately preceding vehicle information may be image information obtained by capturing the front of the vehicle with a camera.

  The wide-area road-to-vehicle communication device 11 is a communication device that receives wide-area traffic congestion information transmitted from a center that manages wide-area road traffic information through wide-area communication. The traffic jam information in the wide area includes, for example, location information where the traffic jam occurs, length information of each traffic jam section, and travel time. An example of a wide area communication method is FM multiplex broadcasting. When the wide-area road-to-vehicle communication device 11 receives the traffic information of the wide area, it outputs the traffic information of the wide area to the ECU 30. In the example shown in FIG. 2, the own vehicle MV equipped with the ACC system 1 receives the radio wave R transmitted from a distant center (not shown) and obtains traffic information in a wide area.

  The narrow-area road-to-vehicle communication device 12 is a communication device that receives traffic information of a narrow area transmitted from a center that manages road traffic information of each area (sensor section) by narrow-area communication. The traffic jam information in the narrow area includes, for example, the number of vehicles (traffic volume), average speed, and travel time in the sensor section. Examples of the narrow area communication method include an optical beacon and a radio beacon. When the narrow-area road-to-vehicle communication device 12 receives the traffic information of the narrow area, the traffic information of the narrow area is output to the ECU 30. In the example shown in FIG. 2, the control center S collects information on sensor sections detected by sensors such as the traffic counters T1, T2, and obtains the number of passing vehicles, average vehicle speed, travel time, etc. from the collected information, The information is transmitted from beacon B. The own vehicle MV equipped with the ACC system 1 receives radio waves transmitted from the beacon B and obtains traffic jam information in a narrow area.

  In such narrow-area road-to-vehicle communication, information can be transmitted from the vehicle to the center using a beacon or the like. Therefore, by transmitting information that the vehicle is equipped with the ACC system 1 from the vehicle to the center, the ratio of the vehicles equipped with the ACC system 1 traveling in the sensor section at the center (the system installation for the total number of vehicles in the sensor section). The vehicle ratio) can be calculated and the travel ratio information of the vehicle equipped with the system can be transmitted.

  The inter-vehicle communication device 13 is a communication device that transmits and receives information to and from other vehicles capable of communicating between vehicles (particularly, other vehicles equipped with the ACC system 1). Examples of information to be transmitted / received include position information, speed information, and whether or not the ACC system 1 is installed. When the inter-vehicle communication device 13 receives information transmitted from another vehicle, it outputs the information to the ECU 30. In addition, the inter-vehicle communication device 13 transmits the own vehicle information detected by the autonomous sensor 10 to another vehicle. In the example shown in FIG. 2, the host vehicle MV equipped with the ACC system 1 receives radio waves from another vehicle OV capable of inter-vehicle communication, obtains information on the other vehicle OV, and detects traffic jam information.

  The ECU 30 can determine whether or not there is a traffic jam around the own vehicle by using the information of each other vehicle in the vicinity, and in the case of the traffic jam, the distance of the traffic jam section, the average speed, and the like can be calculated. Furthermore, if all the vehicles are capable of inter-vehicle communication, the ECU 30 can calculate the travel ratio of the vehicles equipped with the ACC system 1 in the traffic jam section.

  In addition, as means for obtaining the traffic jam information, there may be at least one of the autonomous sensor 10, the wide-area road-to-vehicle communication apparatus 11, the narrow-area road-to-vehicle communication apparatus 12, and the inter-vehicle communication apparatus 13. . Information accuracy is obtained by the vehicle-to-vehicle communication device 13, information obtained by the narrow-area road-to-vehicle communication device 12, information obtained by the wide-area road-to-vehicle communication device 11, and obtained by the autonomous sensor 10. Highly accurate information can be obtained in the order of information. In addition, if there is any other means for obtaining traffic information, the obtaining means may be used.

  The throttle actuator 20 is an actuator that adjusts the opening of a throttle valve (not shown). The throttle actuator 20 operates according to a throttle control signal from the ECU 30 and adjusts the opening of the throttle valve.

  The brake actuator 21 is an actuator that adjusts the brake hydraulic pressure of a wheel cylinder (not shown) of each wheel. The brake actuator 21 operates in accordance with a brake control signal from the ECU 30 to adjust the brake hydraulic pressure of the wheel cylinder.

  The ECU 30 is an electronic control unit including a CPU [Central Processing Unit], a ROM [Read Only Memory], a RAM [Random Access Memory], and the like, and performs overall control of the ACC system 1. The ACC ECU 30 configures an information processing function, an upper limit speed setting function, a steady speed traveling control function, and a follow-up traveling control function by loading an application program stored in the ROM into the RAM and executing it by the CPU. The steady speed travel control function and the follow travel control function include a normal travel mode and a traffic jam section travel mode.

  The information processing function will be described. In ECU30, the own vehicle information is input from the autonomous sensor 10, and the speed and position of the own vehicle are obtained. The ECU 30 calculates the acceleration of the own vehicle from the time change of the speed of the own vehicle. Further, the ECU 30 inputs the immediately preceding vehicle information (radar information or the like) from the autonomous sensor 10 and determines the presence or absence of the immediately preceding vehicle based on the immediately preceding vehicle information. Calculate the relative speed and the speed of the preceding vehicle. The ECU 30 calculates the acceleration of the immediately preceding vehicle from the time change of the speed of the immediately preceding vehicle.

  Further, the ECU 30 inputs the traffic information of the wide area from the wide area road-to-vehicle communication device 11 and obtains the location and length of the traffic in the wide area including the own vehicle. In addition, the ECU 30 inputs the traffic information of the narrow area from the narrow area road-to-vehicle communication device 12, and obtains the number of vehicles, the average speed and travel time in the sensor section in front of the host vehicle, and the traveling ratio of the system-equipped vehicles. . Further, the ECU 30 inputs information on other vehicles from the inter-vehicle communication device 13 and determines whether there is traffic jam ahead of the host vehicle based on the information on other vehicles that can be input. Calculate distance, average speed, etc.

  Then, the ECU 30 determines whether or not the road ahead of the host vehicle is congested based on the obtained information. When there is a traffic jam on the road ahead of the host vehicle, the ECU 30 identifies the traffic jam section and identifies the average speed and travel ratio in the traffic jam section. In addition, the ECU 30 specifies a traffic jam elimination position at which the traffic jam section ends. Then, the ECU 30 determines whether or not the current position of the vehicle has passed the congestion elimination position, and if it has passed, determines that the vehicle has passed the congestion section.

  The upper limit speed setting function will be described. When there is a traffic jam on the road ahead of the vehicle, the ECU 30 sets the speed obtained by adding the additional speed X to the traffic jam definition speed if the average speed in the traffic jam section is not available. The congestion definition speed is, for example, 40 [km / h] for a highway and 20 [km / h] for a general road. Further, the ECU 30 sets an upper limit speed according to the traveling ratio of the system-equipped vehicle when the average speed in the traffic congestion section is available, or when the traveling ratio of the system-equipped vehicle in the traffic congestion section is available, When the traveling rate of the system-equipped vehicle in the section is not available, the speed obtained by adding the addition speed X to the average speed in the traffic jam section is set as the upper limit speed.

  The addition speed X [km / h] is a speed for increasing the average speed of the entire traffic jam section from the current average speed, and is set by experiment, simulation, or the like. The addition speed X may be set for each type of road (highway, city highway, general road, etc.), and a higher speed may be set as the congestion definition speed for each road type is higher. The addition speed X is a speed in a range where the upper limit speed does not exceed the legal speed.

  As the traveling ratio of the system-equipped vehicles increases in the traffic jam section, the number of vehicles traveling with the upper limit speed as the upper limit increases, so that the speed in the entire traffic jam section can be increased. Therefore, when the upper limit speed is set in accordance with the travel ratio of the system-equipped vehicle in the traffic jam section, the higher the travel ratio, the higher the speed is set by adding a larger added speed to the average speed in the traffic jam section. As a setting method, for example, an upper limit speed map in which an upper limit speed corresponding to the travel ratio is set for each average speed in a traffic jam section is prepared in advance, and the upper limit speed is set based on the upper limit speed map. The upper limit speed to be set according to the running ratio is set by experiment, simulation, or the like.

  The steady speed traveling control function will be described. When there is no previous vehicle ahead of the host vehicle and there is no traffic jam on the road ahead of the host vehicle (normal travel mode), the ECU 30 determines the host vehicle speed based on the difference between the host vehicle speed and the target speed at regular intervals. Calculates the target acceleration required to reach the target speed. When the target acceleration is a positive value, the ECU 30 calculates the target driving force from the target acceleration, sets the target opening of the throttle valve necessary for achieving the target driving force, and uses the target opening as a throttle control signal. Output to the throttle actuator 20. On the other hand, when the target acceleration is a negative value (that is, target deceleration), the ECU 30 calculates the target braking force from the target acceleration and brakes the wheel cylinders of each wheel necessary to obtain the target braking force. The hydraulic pressure is set, and the brake hydraulic pressure is output to the brake actuator 21 as a brake control signal.

  When there is no immediately preceding vehicle in front of the host vehicle and traffic is congested on the road ahead of the host vehicle, the ECU 30 sets the host vehicle speed to the upper limit speed at regular intervals based on the difference between the host vehicle speed and the upper limit speed. Therefore, the target acceleration necessary for the calculation is calculated, and the same processing as described above is performed using the target acceleration. In addition, when there is a vehicle in front of the host vehicle and traffic is congested on the road ahead of the host vehicle (traffic zone travel mode), the ECU 30 determines the vehicle speed and upper limit speed of the host vehicle when the speed of the preceding vehicle is higher than the upper limit speed. Based on this difference, the target acceleration necessary for the host vehicle speed to become the upper limit speed is calculated, and the same processing as described above is performed using this target acceleration.

  The following traveling control function will be described. When there is a preceding vehicle ahead of the host vehicle and there is no traffic jam on the front road of the host vehicle (normal travel mode), the ECU 30 determines whether the acceleration of the immediately preceding vehicle is equal to or greater than 0 at regular intervals. If the acceleration of the immediately preceding vehicle is greater than or equal to 0 (acceleration following travel control), the target required for the inter-vehicle distance to the immediately preceding vehicle to be the target inter-vehicle distance based on the difference between the inter-vehicle distance from the immediately preceding vehicle and the target inter-vehicle distance Calculate acceleration (plus value). Then, the ECU 30 calculates the target driving force from the target acceleration, sets the target opening of the throttle valve necessary for achieving the target driving force, and outputs the target opening to the throttle actuator 20 as a throttle control signal. . On the other hand, when the acceleration of the immediately preceding vehicle is less than 0 (deceleration following travel control), the ECU 30 sets the inter-vehicle distance to the immediately preceding vehicle as the target inter-vehicle distance based on the difference between the inter-vehicle distance from the immediately preceding vehicle and the target inter-vehicle distance. The target acceleration (minus value: target deceleration) necessary for this is calculated. Then, the ECU 30 calculates a target braking force from the target acceleration, sets the brake hydraulic pressure of the wheel cylinder of each wheel necessary for achieving the target braking force, and uses the brake hydraulic pressure as a brake control signal to the brake actuator 21. Output.

  When there is a preceding vehicle ahead of the host vehicle and the vehicle is congested on the road ahead of the host vehicle (congested section travel mode), the ECU 30 determines whether the speed of the preceding vehicle is equal to or lower than the upper limit speed at regular intervals. When the speed of the immediately preceding vehicle is less than or equal to the upper limit speed, the ECU 30 determines whether or not the acceleration of the immediately preceding vehicle is equal to or greater than 0 at regular time intervals. The ECU 30 performs acceleration follow-up running control similar to the above when the acceleration of the immediately preceding vehicle is 0 or more, and performs deceleration follow-up running control similar to the above when the acceleration of the immediately preceding vehicle is less than 0. At this time, the target inter-vehicle distance is set according to the own vehicle speed or the like, and gradually decreases as the own vehicle speed decreases. On the other hand, when the speed of the immediately preceding vehicle is higher than the upper limit speed, the ECU 30 performs processing by the above-described steady travel control function.

  With reference to FIG.2 and FIG.3, the behavior when the own vehicle enters the traffic jam section when the control is performed by the conventional ACC system and when the control is performed by the ACC system 1 will be described. In the example shown in FIG. 2, a traffic jam occurs in the sag portion, and a traffic jam section extends backward from the sag portion. Each vehicle traveling in such a traffic jam section repeats deceleration, stop, and acceleration (start). For this reason, once the vehicle stops, if the start at the time of acceleration is delayed from the stop, it causes further congestion of the following vehicle.

  The upper graph of FIG. 3 shows the time change of the speed Vm ′ of the host vehicle equipped with the conventional ACC system and the speed Vpre ′ of the vehicle just before that in the traffic jam section. As can be seen from the time changes Vm ′ and Vpre ′ of the speeds of these two vehicles, when the preceding vehicle repeatedly decelerates, stops, and accelerates (starts), even the own vehicle that performs the follow-up control of the conventional ACC system, Stop and accelerate (start) repeatedly after a short delay. At this time, in the own vehicle in which the follow-up control of the conventional ACC system is performed, the vehicle accelerates to the same speed as the speed reached by the immediately preceding vehicle. However, since the vehicle decelerates after acceleration as described above in a traffic jam section, it is not necessary to accelerate to a high speed as in the case of the immediately preceding vehicle, resulting in useless acceleration.

  Therefore, in the ACC system 1, an upper limit speed higher than the average speed in the traffic congestion section is set, acceleration is stopped with the upper limit speed as an upper limit, and steady running is performed at the upper limit speed. In the upper graph of FIG. 3, the upper limit speed Vup is set with respect to the average speed Vave in the traffic jam section, and the time change of the speed Vm of the own vehicle equipped with the ACC system 1 is also shown. As can be seen from the speed time change Vm of the own vehicle and the speed time change Vpre 'of the immediately preceding vehicle, the own vehicle stops acceleration up to the upper limit speed Vup even when the immediately preceding vehicle is accelerating above the upper limit speed Vup. The vehicle runs at a constant speed at the upper limit speed Vup. As a result, the host vehicle can suppress unnecessary acceleration, and the distance between the vehicle and the immediately preceding vehicle is increased. Comparing the inter-vehicle distance between the own vehicle and the preceding vehicle and the inter-vehicle distance between the immediately preceding vehicle and the preceding vehicle, the inter-vehicle distance between the own vehicle and the immediately preceding vehicle is sufficiently wide. For this reason, when the preceding vehicle is decelerating after acceleration, the host vehicle also decelerates if the speed of the immediately preceding vehicle falls below the upper limit speed. It is slower than the slowdown.

  As a result, the own vehicle can suppress a decrease in speed when decelerating, and the number of times to stop is also reduced. Therefore, the number of times that the following vehicle stops is also reduced, and the number of times of starting during acceleration after the stop is also reduced. The lower graph of FIG. 3 shows the time change of the speed Vm of the own vehicle equipped with the ACC system 1 and the speed Vn of the vehicle following the vehicle (vehicle not equipped with the ACC system 1) in the traffic jam section. As can be seen from the speed time change Vm of both vehicles and the speed time change Vn of the following vehicle, the following vehicle and the following vehicle are accelerated to the upper limit speed, and the following vehicle and the following vehicle are not stopped. As a result, the average speed in the entire traffic jam section gradually increases, the travel time is shortened, and the traffic jam is resolved quickly. Therefore, it is not necessary for all the vehicles in the traffic jam section to have the ACC system 1 to perform the above control, and only some of the vehicles in the traffic jam section have the ACC system 1 to perform the above control. The traffic flow in a congested section can be improved simply by doing.

  The operation in the ACC system 1 will be described with reference to FIG. In particular, the processing in the ECU 30 will be described along the flowcharts of FIGS. 4 and 5. FIG. 4 is a flowchart showing a flow of main processing of the ECU in the ACC system of FIG. FIG. 5 is a flowchart showing the flow of the upper limit speed setting process of the ECU in the ACC system of FIG.

  The autonomous sensor 10 detects information on the own vehicle at regular intervals, and outputs the detected own vehicle information to the ECU 30. In addition, the autonomous sensor 10 detects information on the immediately preceding vehicle ahead of the host vehicle at regular time intervals, and outputs the detected immediately preceding vehicle information to the ECU 30. Each time the information is transmitted from the center, the wide area road-to-vehicle communication device 11 receives wide area traffic congestion information and outputs the received wide area traffic congestion information to the ECU 30. In addition, the narrow-area road-to-vehicle communication device 12 receives narrow-area traffic jam information each time the vehicle passes through the narrow-area information provision area, and outputs the received narrow-area traffic jam information to the ECU 30. The inter-vehicle communication device 13 receives information on other vehicles every time information is transmitted from other vehicles existing within the communicable area, and outputs the received other vehicle information to the ECU 30. In the ECU 30, when information is output from the sensor 10 or each of the communication devices 11, 12, 13, the information is input.

  The ECU 30 obtains the road conditions ahead of the vehicle (the location of the traffic jam, the length of the traffic jam, the average speed of the traffic jam (Vave), the traffic jam elimination position (Dend), etc.) based on the input information (S10). . Then, the ECU 30 determines whether or not the vehicle is congested on the road ahead of the vehicle (S11). When it is determined in S11 that there is no traffic jam, the ECU 30 performs steady speed travel control based on the target speed in the normal travel mode, and when acceleration is required, outputs a throttle control signal to the throttle actuator 20 for deceleration. If necessary, a brake control signal is output to the brake actuator 21 (S12). When a throttle control signal is input, the throttle actuator 20 operates according to the throttle control signal and adjusts the opening of the throttle valve. Further, when a brake control signal is input, the brake actuator 21 operates according to the target hydraulic pressure, and adjusts the brake hydraulic pressure of the wheel cylinder. As a result, the speed of the host vehicle is adjusted to the target speed.

  If it is determined in S11 that the vehicle is congested, the ECU 30 obtains the traveling ratio of the system-equipped vehicle in the congested section based on the input various information (S13). Then, the ECU 30 sets an upper limit speed (Vup) in the traffic jam section based on the obtained travel ratio (S14). The upper limit speed setting process will be described in detail later.

  Based on the information input from the autonomous sensor 10, the ECU 30 obtains information on the vehicle immediately before the host vehicle (S15). Then, the ECU 30 determines whether or not the immediately preceding vehicle has been detected based on the immediately preceding vehicle information (S16). If it is determined in S16 that the immediately preceding vehicle is not detected, the ECU 30 performs steady speed traveling control based on the upper limit speed (Vup) of the traffic jam section, and if acceleration is required, the throttle control signal is sent to the throttle actuator 20 If deceleration is required, a brake control signal is output to the brake actuator 21 (S17). The throttle actuator 20 or the brake actuator 21 operates in the same manner as described above. As a result, in the own vehicle, there is no immediately preceding vehicle in the traffic jam section, so the speed is adjusted to be a constant speed of the upper limit speed (Vup).

  When it is determined in S16 that the immediately preceding vehicle has been detected, the ECU 30 shifts to a traffic jam section travel mode (S18). Then, the ECU 30 calculates the speed (Vpre) of the immediately preceding vehicle based on the information input from the autonomous sensor 10 (S19), and determines whether the speed (Vpre) of the immediately preceding vehicle is equal to or less than the upper limit speed (Vup) ( S20). When it is determined in S20 that the speed (Vpre) of the immediately preceding vehicle is higher than the upper limit speed (Vup), the ECU 30 performs steady speed traveling control based on the upper limit speed (Vup) of the traffic jam section, and acceleration is required. Outputs a throttle control signal to the throttle actuator 20, and outputs a brake control signal to the brake actuator 21 when deceleration is required (S21). The throttle actuator 20 or the brake actuator 21 operates in the same manner as described above. Thereby, in the own vehicle, the vehicle immediately before exists in the traffic jam section, but the speed is adjusted to be a constant speed of the upper limit speed (Vup).

  When it is determined in S20 that the speed (Vpre) of the immediately preceding vehicle is equal to or lower than the upper limit speed (Vup), the ECU 30 calculates the acceleration (Apre) of the immediately preceding vehicle based on the information input from the autonomous sensor 10 (S22). It is determined whether or not the vehicle acceleration (Apre) is smaller than 0 (S23). When it is determined in S23 that the acceleration (Apre) of the immediately preceding vehicle is smaller than 0, the ECU 30 performs deceleration follow-up running control based on a preset target inter-vehicle distance and outputs a brake control signal to the brake actuator 21 ( S24). The brake actuator 21 operates in the same manner as described above. As a result, the own vehicle decelerates following the immediately preceding vehicle in the traffic jam section. When it is determined in S23 that the acceleration (Apre) of the immediately preceding vehicle is 0 or more, the ECU 30 performs acceleration follow-up running control based on a preset target inter-vehicle distance, and outputs a throttle control signal to the throttle actuator 20 (S25). ). The throttle actuator 20 operates in the same manner as described above. As a result, the host vehicle accelerates following the immediately preceding vehicle in a traffic jam section.

  Then, the ECU 30 obtains the current position of the own vehicle based on the information input from the autonomous sensor 10, and determines whether or not the current position of the own vehicle has passed the congestion elimination position (Dend) (S26). If it is determined in S26 that the current position of the vehicle has not passed the congestion elimination position (Dend), the ECU 30 returns to the process of S19 and continues control of the congestion zone travel mode.

  When it is determined in S26 that the current position of the vehicle has passed the congestion elimination position (Dend), the ECU 30 ends the congestion section running mode and shifts to the normal running mode, and the acceleration (Apre) of the immediately preceding vehicle is 0. When it is smaller, deceleration follow-up running control is performed, and when the acceleration (Apre) of the immediately preceding vehicle is 0 or more, acceleration follow-up running control is performed (S27). As a result, the host vehicle accelerates and decelerates following the preceding vehicle.

  The setting process of the upper limit speed (Vup) will be described. The ECU 30 determines whether or not traffic information can be obtained (S30). If it is determined in S30 that the traffic jam information is not available, the ECU 30 waits until it is available.

  When it is determined in S30 that traffic jam information is available, the ECU 30 determines whether the average speed (Vave) of the traffic jam section is available (S31). If it is determined in S31 that the average speed (Vave) of the traffic jam section is not available, the ECU 30 adds the additional speed X [km / h] to the traffic jam definition speed (S32) and determines the upper limit speed (Vup). (S36). For example, in the case of an expressway, if the congestion definition speed is 40 [km / h], 40 + X [km / h] is the upper limit speed (Vup).

  If it is determined in S31 that the average speed (Vave) of the traffic jam section is available, the ECU 30 determines whether or not the travel ratio of the system-equipped vehicle is available (S33). When it is determined in S33 that the traveling rate of the system-equipped vehicle is not available, the ECU 30 adds the additional speed X [km / h] to the average speed (Vave) of the traffic jam section (S34), and the upper limit speed (Vup) (S36). For example, if the average speed (Vave) of a traffic jam section is 30 [km / h], 30 + X [km / h] is the upper limit speed (Vup).

  When it is determined in S33 that the traveling ratio of the system-equipped vehicle is available, the ECU 30 calculates the upper limit speed according to the traveling ratio of the system-equipped vehicle (S35) and determines it as the upper limit speed (Vup) (S36). ). For example, FIG. 6 shows an example of an upper limit speed map when the average speed (Vave) of a traffic jam section is 30 [km / h]. In the case of this upper limit speed map, 40 [km / h] is set as the upper limit speed when the traveling rate of the system-equipped vehicle is 5%, and 45 [km / h] is set as the upper limit speed when it is 10%. In the case of 20%, 50 [km / h] is set as the upper limit speed. When the actual travel ratio is a numerical value other than the value set in the upper limit speed map, the upper limit speed is calculated by interpolation according to the actual travel ratio value. Alternatively, a value closest to the actual travel ratio value is selected from the values set in the upper limit speed map, and the upper limit speed of the travel ratio in the selected upper limit speed map is set as it is.

  With reference to FIG.7 and FIG.8, the simulation experiment actually performed using the vehicle carrying the ACC system 1 which concerns on this Embodiment is demonstrated. FIG. 7 shows an analysis result of a simulation experiment in which the vehicle equipped with the ACC system according to the present embodiment is actually used. FIG. 8 shows the speed change of each vehicle and the inter-vehicle distance change between the host vehicle and the immediately preceding vehicle in a simulation experiment in which the ACC system-equipped vehicle according to the present embodiment is actually used.

  In this simulation experiment, traffic jams were actually generated on the 8km lanes and overtaking lanes including the sag on the motorway, and 5% of the vehicles in the traffic zone were equipped with the ACC system 1. Randomly run at a rate. In this traffic jam section, the average speed was about 35 km / h.

FIG. 7 shows the analysis results for this simulation experiment. When the upper limit speed was set to 30 [km / h], the number of stops in the traffic jam section was reduced by 3.67 [times], and the reduction effect was 54.28 [%]. The travel time of the traffic jam section increased by 130.91 [s], and the increase rate was 30.10 [%]. The CO ₂ emission amount in the traffic jam section was reduced by 114.94 [g], and the reduction effect was 8.57 [%]. The average speed of the traffic jam section decreased by 3.32 [m / s], and the decrease rate was 22.80 [%]. When the upper limit speed is set to 30 [km / h], the speed is lower than the average speed of the traffic jam section, so the average speed of the entire traffic jam section decreases and the travel time becomes longer.

When the upper limit speed was set to 40 [km / h], the number of stops in the traffic jam section was reduced by 4.64 [times], and the reduction effect was 61.04 [%]. The travel time in the traffic jam section was reduced by 64.50 [s], and the reduction effect was 14.83 [%]. The CO ₂ emission amount in the traffic jam section was reduced by 230.74 [g], and the reduction effect was 17.20 [%]. The average speed of the traffic jam section increased by 2.44 [m / s], and the recovery effect was 16.74 [%].

When the upper limit speed was set to 45 [km / h], the number of stops in the traffic jam section was reduced by 3.95 [times], and the reduction effect was 51.96 [%]. The travel time in the traffic jam section was reduced by 64.78 [s], and the reduction effect was 14.90 [%]. The CO ₂ emission amount in the traffic jam section was reduced by 217.404 [g], and the reduction effect was 16.21 [%]. The average speed of the traffic jam section increased by 2.45 [m / s], and the recovery effect was 16.21 [%].

When the upper limit speed is set to 40 [km / h] or 45 [km / h], the speed is higher than the average speed of the traffic jam section, so the number of stops decreases and the average speed of the entire traffic jam section increases, resulting in travel time. Is shorter. Furthermore, CO ₂ emissions are also decreasing. Thus, even when the number of system-equipped vehicles is 5%, it has been demonstrated that the effect of improving the traffic flow in the congested section can be sufficiently obtained by setting the upper limit speed higher than the average speed of the congested section.

  FIG. 8 shows an example of the time change in the speed of an arbitrary system-equipped vehicle and the preceding and subsequent non-system equipped vehicles and the inter-vehicle distance between the system equipped vehicle and the immediately preceding non-system equipped vehicle in this simulation experiment. Is shown. The upper limit speed of this system-equipped vehicle is 40 [km / m] (= about 11 [m / s]). The speed change V1 of the system-equipped vehicle is indicated by a solid bold line, the speed change V2 of the non-system-equipped vehicle immediately before the system-equipped vehicle is indicated by a broken line, and the speed changes V3 and V4 of the subsequent non-system-equipped vehicles of the system-equipped vehicle It is indicated by a solid thin line, and the inter-vehicle distance change L1 between the system-equipped vehicle and the immediately preceding non-system-equipped vehicle is indicated by a one-dot chain line.

  The speed change V1 of the vehicle equipped with the system basically changes following the speed change V2 of the immediately preceding vehicle because it travels following the immediately preceding vehicle, but the speed V2 of the immediately preceding vehicle is 40 [km / m]. If it exceeds, it will become a constant speed of 40 [km / m]. The speed changes V3 and V4 of the following vehicles change according to the speed change V1 of the system-equipped vehicle. Even if the speed V2 of the immediately preceding vehicle exceeds 40 [km / m], it is 40 [km] as in the system-equipped vehicle. / M]. In addition, the inter-vehicle distance L1 between the system-equipped vehicle and the immediately preceding vehicle is increased when the speed V2 of the immediately preceding vehicle exceeds 40 [km / m] because the system-equipped vehicle has a constant speed of 40 [km / h]. go. By using this widened inter-vehicle distance, the system-equipped vehicle also decelerates when the preceding vehicle decelerates. However, as can be seen from the speed change V1 of the system-equipped vehicle and the speed change V2 of the immediately preceding vehicle, the deceleration of the system-equipped vehicle is reduced. It is suppressed more than the car just before. As a result, even if the immediately preceding vehicle stops (speed = 0 [m / s]), the system-equipped vehicle does not stop. In addition, the number of stoppages has decreased for the vehicles following the system.

According to the ACC system 1, by setting the upper limit speed higher than the average speed in the traffic jam section and performing the speed control, it is possible to reduce unnecessary acceleration and secure a sufficient inter-vehicle distance during the immediately preceding vehicle acceleration. Can reduce the number of stops and improve the traffic flow in a traffic jam section. Since the number of stops in the traffic jam section is reduced, the start delay from the stop is reduced, and the travel time (passing time) in the traffic jam section can be shortened. Further, since the upper limit speed is set higher than the average speed in the traffic jam section, the average speed in the traffic jam section increases, and the travel time in the traffic jam section can be shortened. As a result, early congestion can be eliminated and CO ₂ emissions can be reduced. In addition, even if some vehicles are equipped with the ACC system 1 in the traffic jam section (for example, 5% of the total number of vehicles in the traffic jam section), the traffic flow improvement effect in the traffic jam section can be sufficiently obtained.

  Furthermore, according to the ACC system 1, the average speed in the traffic jam section can be further increased by setting the upper limit speed according to the traveling ratio of the vehicle equipped with the ACC system 1 in the traffic jam section. The flow can be improved.

  As mentioned above, although embodiment which concerns on this invention was described, this invention is implemented in various forms, without being limited to the said embodiment.

  For example, although the present embodiment is applied to the ACC system, it can also be applied to other driving support devices such as an automatic driving system and an information providing system.

  In the present embodiment, the ECU of the ACC system is configured to set the upper limit speed in the traffic congestion section. However, the upper limit speed is set by a similar method in the center that collects the traffic congestion information, and the upper speed limit is set for road-to-vehicle communication. You may make it notify to each vehicle using.

  Further, in this embodiment, the present invention is applied to the ACC system and is configured to adjust to the optimum speed by speed control (intervention control) using a brake actuator or a throttle actuator. In particular, an upper limit speed in a traffic jam section may be provided and the driver may be guided to travel at the target speed.

  In the present embodiment, the upper limit speed in the traffic jam section is set according to the travel rate of the system-equipped vehicle. However, the upper limit speed may be set regardless of the travel rate of the system-equipped vehicle.

  DESCRIPTION OF SYMBOLS 1 ... ACC system, 10 ... Autonomous sensor, 11 ... Wide area road-to-vehicle communication apparatus, 12 ... Narrow area road-to-vehicle communication apparatus, 13 ... Inter-vehicle communication apparatus, 20 ... Throttle actuator, 21 ... Brake actuator, 30 ... ECU.

Claims (2)

A driving support device that performs driving support in a traffic jam section,
An average speed acquisition means for acquiring an average speed of a traffic jam section;
Upper limit speed setting means for setting a speed higher than the average speed of the traffic jam section acquired by the average speed acquisition means as an upper speed limit in the traffic jam section;
And a driving support unit that performs driving support based on an upper limit speed in a traffic jam section set by the upper limit speed setting unit. A travel rate acquisition means for acquiring a rate at which a vehicle equipped with the driving support device is traveling in a traffic jam section;
The driving support device according to claim 1, wherein the upper limit speed setting unit sets an upper limit speed according to the travel rate acquired by the travel rate acquisition unit.

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