JP2009202711A - Traveling control device and method for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly control other vehicle even when any information about the other vehicle is not acquired. <P>SOLUTION: A traveling control device for vehicle acquires information on other vehicle (step S8). Before one vehicle enters a curve, the traveling control device determines the presence of an oncoming vehicle which may pass by the one vehicle in the curve section based on the acquired information of the other vehicle (step S9, step S10). When determining the presence of the oncoming vehicle, the traveling control device controls the one vehicle according to the curve in response to the oncoming vehicle traveling in the curve section (steps S11 to step S18). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicular travel control apparatus that controls travel of a host vehicle corresponding to another vehicle and a method therefor.

Patent Document 1 discloses a technique for controlling travel of the host vehicle using road-to-vehicle communication or the like. In patent document 1, the information of the other vehicle which exists in a target area | region is acquired by road-to-vehicle communication etc., and alerting | reporting etc. are performed in the own vehicle. Here, road-to-vehicle communication is performed via a fixed station installed on the side of the road or the like.
JP 2001-109989 A

By the way, the communication area of the in-vehicle communication device and the fixed station is limited. For this reason, when the traveling area of the host vehicle is outside the communication area of the in-vehicle communication device, information on other vehicles cannot be obtained. In addition, even if the travel area of another vehicle is outside the communication area of the fixed station, the information on the other vehicle cannot be obtained in the own vehicle. In these cases, even if the own vehicle is controlled (for example, alarm output control) for another vehicle using the technique disclosed in Patent Document 1, the control may not be appropriate. In particular, when other vehicles for which information is not available are traveling in a curve section, even if the vehicle is controlled to travel corresponding to such a curve, the traveling control is not appropriate. .
Accordingly, an object of the present invention is to appropriately perform control for another vehicle even when information about the other vehicle cannot be obtained.

  In order to solve the above-mentioned problem, the present invention acquires information on another vehicle before the host vehicle enters the curve, and based on the acquired information, there is a possibility of passing the host vehicle in the curve section. The presence or absence of a vehicle is determined. When it is determined that there is an oncoming vehicle, the host vehicle is controlled corresponding to the curve while corresponding to the oncoming vehicle traveling in the curve section.

  According to the present invention, it is possible to determine the presence or absence of an oncoming vehicle that may pass through a curve section based on information on other vehicles acquired before the host vehicle enters the curve. Furthermore, when it is determined that there is an oncoming vehicle, it is possible to control the host vehicle corresponding to the curve while corresponding to the oncoming vehicle traveling in the curve section. Thereby, even when information about another vehicle can no longer be obtained, control for the other vehicle can be appropriately performed.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings.
(Constitution)
The embodiment is a vehicle equipped with the vehicular travel control apparatus according to the present invention. This vehicle is a rear wheel drive vehicle. This vehicle is equipped with an automatic transmission and a conventional differential gear, and a braking device capable of independently controlling the braking force of the left and right wheels for both the front and rear wheels.

  FIG. 1 is a schematic configuration diagram showing the present embodiment. In the figure, reference numeral 1 is a brake pedal, 2 is a booster, 3 is a master cylinder, and 4 is a reservoir. Normally, the brake fluid pressure boosted by the master cylinder 3 is supplied to the wheel cylinders 6FL to 6RR of the wheels 5FL to 5RR in accordance with the depression amount of the brake pedal 1 by the driver. Further, a brake fluid pressure control unit 7 is interposed between the master cylinder 3 and each wheel cylinder 6FL to 6RR. The brake fluid pressure controller 7 individually controls the brake fluid pressures of the wheel cylinders 6FL to 6RR.

  The braking fluid pressure control unit 7 uses a braking fluid pressure control unit used for antiskid control and traction control, for example. The brake fluid pressure controller 7 can also control the brake fluid pressure of each wheel cylinder 6FL-6RR independently. In addition, when a braking fluid pressure command value is input from a braking / driving force control unit 8 described later, the braking fluid pressure control unit 7 can also control the braking fluid pressure according to the braking fluid pressure command value. For example, the brake fluid pressure control unit 7 includes an actuator in the hydraulic pressure supply system. As an actuator, there is a proportional solenoid valve capable of controlling each wheel cylinder hydraulic pressure to an arbitrary braking hydraulic pressure.

  Further, this vehicle is equipped with a drive torque control unit 12. The drive torque control unit 12 controls the drive torque to the rear wheels 5RL and 5RR which are drive wheels by controlling the operating state of the engine 9, the selected gear ratio of the automatic transmission 10, and the throttle opening of the throttle valve 11. To do. The drive torque control unit 12 controls the operating state of the engine 9 by controlling the fuel injection amount and ignition timing, and simultaneously controlling the throttle opening. The drive torque control unit 12 outputs the value of the drive torque Tw used for control to the braking / driving force control unit 8.

The drive torque control unit 12 can also control the drive torque of the rear wheels 5RL and 5RR independently. Further, when a driving torque command value is input from the braking / driving force control unit 8, the driving torque control unit 12 can also control the driving wheel torque according to the driving torque command value.
In addition, this vehicle is equipped with an imaging unit 13 with an image processing function. The imaging unit 13 detects the position of the host vehicle in the traveling lane for detecting the lane departure tendency of the host vehicle. For example, the imaging unit 13 is configured to capture an image with a monocular camera including a CCD (Charge Coupled Device) camera. An imaging unit 13 is installed in the front part of the vehicle.

  The imaging unit 13 detects a lane marker such as a white line from a captured image in front of the host vehicle, and detects a traveling lane based on the detected lane marker. Furthermore, the imaging unit 13 determines, based on the detected travel lane, an angle (yaw angle) φ between the travel lane of the host vehicle and the longitudinal axis of the host vehicle, a lateral displacement X from the center of the travel lane, and a travel lane curvature. β and the like are calculated. The imaging unit 13 outputs the calculated yaw angle φ, lateral displacement X, travel lane curvature β, and the like to the braking / driving force control unit 8.

  The vehicle is equipped with a navigation device 14. The navigation device 14 retrieves road information (node information) ahead of the host vehicle from the host vehicle position measured by GPS (Global Positioning System) and map information. The navigation device 14 outputs the node information as a search result to the braking / driving force control unit 8. The navigation device 14 also outputs road information to the braking / driving force control unit 8. The road information includes road type information indicating the road type such as the number of lanes, general roads, and highways. In the present embodiment, the navigation device 14 functions as a forward curve detection unit. However, it is also possible to use road-vehicle communication means for detecting similar curve information by communication from an infrastructure facility installed in front of the curve.

This vehicle is equipped with a warning monitor 31. The warning monitor 31 has a built-in speaker that outputs sound and buzzer sound. A warning monitor 31 is arranged in front of the driver in the passenger compartment. When the warning monitor 31 detects a forward curve that activates automatic deceleration control, it outputs a message to that effect.
In addition, this vehicle is equipped with a communication device 32 that performs vehicle-to-vehicle communication and road-to-vehicle communication via an antenna. The communication device 32 collects oncoming vehicle information and outputs the collected result to the braking / driving force control unit 8.

  The vehicle also includes an acceleration sensor 15 that detects longitudinal acceleration Yg and lateral acceleration Xg generated in the host vehicle. The acceleration sensor 15 outputs the detected longitudinal acceleration Yg and lateral acceleration Xg to the braking / driving force control unit 8. Further, this vehicle includes a yaw rate sensor 16 that detects a yaw rate φ ′ (= dφ / dt) generated in the host vehicle. The yaw rate sensor 16 outputs the detected yaw rate φ ′ to the braking / driving force control unit 8. The longitudinal acceleration Yg, the lateral acceleration Xg, and the yaw rate φ ′ can be detected by the navigation device 14.

Further, this vehicle is equipped with a master cylinder pressure sensor 17 for detecting the output pressure of the master cylinder 3, that is, master cylinder hydraulic pressures Pmf and Pmr. In addition, this vehicle is equipped with an accelerator opening sensor 18 for detecting an accelerator pedal depression amount, that is, an accelerator opening θt, and a steering angle sensor 19 for detecting a steering angle (steering steering angle) δ of the steering wheel 21. Yes. In addition, this vehicle includes a direction indicator switch 20 that detects a driver's operation of a direction indicator (turn signal switch), and a rotation speed of each wheel 5FL to 5RR, so-called wheel speed Vwi (i = fl, fr, rl, Wheel speed sensors 22FL to 22RR for detecting rr) are mounted. These sensors and the like output the detected detection signal to the braking / driving force control unit 8.
When the detected vehicle traveling state data has left and right directions, the right direction is the positive direction in all cases. That is, the yaw rate φ ′, the lateral acceleration Xg, and the yaw angle φ are positive values when turning right, and the lateral displacement X is a positive value when deviating from the center of the traveling lane to the right. The longitudinal acceleration Yg takes a positive value during acceleration and takes a negative value during deceleration.

Next, calculation processing performed by the braking / driving force control unit 8 will be described.
FIG. 2 shows a calculation processing procedure performed by the braking / driving force control unit 8. For example, the arithmetic processing is executed by timer interruption every predetermined sampling time ΔT every 10 msec. In addition, although the communication process is not provided in the process shown in FIG. 2, the information obtained by the arithmetic process is updated and stored in the storage device as needed, and necessary information is read out from the storage device as needed.

As shown in FIG. 2, when the process is started, first, in step S1, various data are read from each sensor, controller, and control unit. Specifically, the longitudinal acceleration Yg, lateral acceleration Xg, yaw rate φ ′, wheel speed Vwi, steering angle δ, accelerator opening θt, master cylinder hydraulic pressures Pmf and Pmr, and direction switch signals detected by the sensors are read. . Further, the driving torque Tw from the driving torque control unit 12, the yaw angle φ, the lateral displacement X, and the traveling lane curvature β are read from the imaging unit 13. Further, the position (X ₀ , Y ₀ ) of the own vehicle and node information (X _n , Y _n , L _n ) ahead of the own vehicle obtained by the navigation device 14 are read. Here, X _n and Y _n indicating node information indicate the position of the node. Further, L _n indicating the node information indicates a distance from the own vehicle position (X ₀ , Y ₀ ).

Subsequently, in step S2, the vehicle speed V is calculated. Specifically, the vehicle speed V is calculated by the following equation (1) based on the wheel speed Vwi read in step S1.
For front wheel drive V = (Vwr1 + Vwrr) / 2
For rear wheel drive V = (Vwfl + Vwfr) / 2
... (1)
Here, Vwfl and Vwfr are the wheel speeds of the left and right front wheels, and Vwrl and Vwrr are the wheel speeds of the left and right rear wheels. That is, in the equation (1), the vehicle speed V is calculated as an average value of the wheel speeds of the driven wheels. In this embodiment, since the vehicle is a rear-wheel drive vehicle, the vehicle speed V is calculated from the latter equation, that is, the wheel speed of the front wheels.
The vehicle speed V calculated in this way is preferably used during normal travel. For example, when an ABS (Anti-lock Brake System) control or the like is operating, an estimated vehicle speed estimated in the ABS control is used as the vehicle speed V. In addition, a value used for navigation information in the navigation device 14 may be used as the vehicle speed V.

Subsequently, in step S3, the turning radius of each node point ahead of the host vehicle is calculated. Specifically, the turning radius of each node point is calculated based on the coordinates (X _n , Y _n ) of each node point read as forward road information in step S1. n is an integer (n = 1, 2, 3,...). Here, several methods for calculating the turning radius can be considered. Among these, in this embodiment, a turning radius is calculated based on the following formula (2).
_{R n = f1 (X n-} 1, Y n-1, X n, Y n, X n + 1, Y n + 1) ··· (2)
Here, the function f1 is a function for calculating the turning radius from the coordinates of the three node points. Here, when the turning radius R _n is negative, indicating a left turn. Further, when the turning radius R _n is a positive value, indicating a right turn. From this equation (2), from the coordinates (X _n-1 , Y _n-1 ), (X _n , Y _n ), (X _{n + 1} , Y _{n + 1} ) of three consecutive node points, the turning radius R _n can be calculated.
The turning radius can also be calculated using an angle formed by a straight line connecting the preceding and following node points. Further, the turning radius of each node point can be stored as node information in the map data, and the stored value (information on the turning radius of each node point) can be obtained in step S3.

Subsequently, in step S4, a curve section is set. Specifically, the curve section is specified by the connection (reciprocal relationship) of the turning radius of each node point. That is, when the host vehicle is not located in a curve section (running in a straight section), among the nodes ahead, the node point (X _i ) where the turning radius is first less than or equal to the set value Rin (R _i ≦ Rin) _{Let i} , Y _i ) be the start point (start node point) of the curve. Among the nodes after the start point of this curve, the node point (X _j , Y _j ) at which the turning radius is first minimized is set as the minimum radius point of the curve. The minimum radius point later in the node, the first turning radius setting value Rout or (R _k ≧ Rout) to become a node point (X _k, Y _k) previous node point (X _k-1 , Y _k-1 ) is the end point of the curve. Alternatively, the node point immediately before the node point where the sign of the turning radius is reversed among the nodes after the minimum radius point is set as the end point (end node point) of the curve. A curve section is specified based on the start point, minimum radius point, and end point of the curve thus obtained. That is, the curve section is a section between the node point that is the start point of the curve and the node point that is the start point of the curve. The subsequent node points are defined in the same manner as long as the information of the node points can be obtained.

Also, a preview distance indicating how far the node point is to be processed is set in accordance with the processing load of the braking / driving force control unit 8 and the vehicle speed. Then, a process for specifying a curve section is performed for the node points included within the set preview distance.
FIG. 3 is a diagram illustrating a procedure for specifying a curve section. When the node points ahead of the host vehicle are as shown in FIGS. 3A and 3B, the start point, minimum radius point, and end point of the curve are as shown in FIGS. 3A and 3B, respectively. Determined.

It is also possible to determine the start point and end point of the curve using the characteristics of the map data. Specifically, the feature of map data is utilized such that a curve has many node points and a straight line has few node points. In this case, first, the change rate Rratio of the turning radius is calculated by the following equation (3).
Rratio = ΔR / Lp (3)
Here, Lp is the distance between node points. ΔR is the difference in turning radius between node points (= | R _i | − | R _i−1 |). FIG. 4 shows values used in this calculation.

And when the following vehicle | formula (4) is materialized when the own vehicle is not located in a curve area, it is set as a curve start point.
Rratio ≦ −Rsratio (4)
Here, Rsratio is a judgment threshold value for the curve start point. Rsratio is a fixed value, for example. In FIG. 4, the value Rratio (= ΔR ₁ / Lp ₁₎ obtained by dividing the difference ΔR ₁ (= | R ₁₁ | − | R ₁₀ |) of the turning radius between the node points by the distance Lp ₁ between the node points. ) Is equal to or less than the judgment threshold value (−Rsratio) of the curve start point. In this case, the node point (X ₁₁ , Y ₁₁ ) becomes the curve start point.

Further, when the following equation (5) is satisfied after the minimum radius point of the curve, it is set as a curve end point.
Rratio ≧ Reratio (5)
Here, Reratio is a curve end point determination threshold value. Reratio is a fixed value, for example. In FIG. 4, a value Rratio (= ΔR ₂ / Lp ₂₎ obtained by dividing the turning radius difference ΔR ₂ (= | R ₁₆ | − | R ₁₅ |) between the node points by the distance Lp ₂ between the node points. ) Is equal to or greater than the curve end point determination threshold Ratio. In this case, the node point (X ₁₅ , Y ₁₅ ) is the curve end point.

As described above, the minimum radius point of the curve is the node point that is the first minimum value after the start point of the curve. On the other hand, first, after determining the curve end point, the node point at which the turning radius becomes the minimum radius between the curve start point and the curve end point can be set as the minimum radius point of the curve.
Subsequently, in step S5, an estimated road surface μ value is calculated. Specifically, the road surface μ estimated value Kμ is calculated by the following equation (6) based on the relationship between the braking / driving force acting on each wheel and the slip generated on each wheel.
Kμ = g (braking / driving force of each wheel, slip ratio of each wheel) (6)
Here, the function g is a function for calculating the road surface μ estimated value Kμ from the relationship between the braking / driving force of each wheel and the slip ratio of each wheel. For example, the function g is obtained experimentally, empirically, or theoretically.

  Thus, the road surface μ estimated value Kμ is calculated from the state of the wheel. On the other hand, when an infrastructure facility (base station or relay device) is installed, the host vehicle can also obtain road surface μ information as curve information from the infrastructure in front of the curve. Further, the road surface μ can be selected by the driver's changeover switch operation. In this case, it becomes easy for the driver to select by enabling the setting (switching) roughly. For example, it is possible to roughly set (switch) high g = 0.8 g, medium g = 0.6 g, low g = 0.4 g, and the like.

In step S6, a target node point is calculated. Specifically, the node point having the smallest turning radius of the latest curve is set as the target node point. As shown in FIG. 3, the node point of the minimum radius point at which the turning radius R _n becomes the first minimum value in front of the host vehicle becomes the target node point.
Subsequently, in step S7, an allowable lateral acceleration Yglmit is set. Specifically, the allowable lateral acceleration Yglimt is set by the following equation (7), for example, using the road surface μ estimated value Kμ calculated in step S5.
Yglimt = Ks · Kμ (7)

  Here, Ks is an allowable lateral acceleration calculation coefficient. The allowable lateral acceleration calculation coefficient Ks is a fixed value (for example, 0.8). Also, the allowable lateral acceleration calculation coefficient Ks can be set according to the host vehicle speed V. FIG. 5 shows an example. As shown in FIG. 5, the allowable lateral acceleration calculation coefficient Ks has a large value in the low speed range. The allowable lateral acceleration calculation coefficient Ks decreases as the host vehicle speed V increases when the host vehicle speed V reaches a certain value. The allowable lateral acceleration calculation coefficient Ks becomes a constant value after reaching a certain vehicle speed V thereafter.

Subsequently, in step S8, the presence or absence of a preceding vehicle is detected. Specifically, using the wireless device 32 installed in each of the host vehicle and the preceding vehicle (other vehicle), vehicle-to-vehicle communication is performed to detect the presence of the preceding vehicle. At this time, vehicle-to-vehicle communication is performed within a certain communication area to detect the presence or absence of a preceding vehicle. For example, as shown in FIG. 6, a range within 500 m ahead of the host vehicle 100 is set as a communication area. In addition, when direct communication with the vehicle ahead cannot be performed by vehicle-to-vehicle communication, communication with the vehicle ahead is performed via infrastructure equipment (base station etc.) installed in the curve section. In addition, information on the preceding vehicle can be managed at a center or the like using road-to-vehicle communication. In this case, when direct communication with the preceding vehicle is not possible, information on the preceding vehicle under the management with the center or the like is acquired via road-to-vehicle communication. Here, as a traveling scene in which communication with the preceding vehicle cannot be performed directly, there is a traveling scene in a curve section with a poor visibility from the host vehicle.
Subsequently, in step S9, information on the oncoming vehicle is acquired. Specifically, when it is determined in step S8 that a forward vehicle exists, a forward vehicle determination process is performed. On the other hand, if it is determined in step S8 that there is no preceding vehicle, the subsequent steps S10 to S11 are skipped and the process proceeds to step S12.

  In the forward vehicle determination process, first, forward vehicle information is acquired by inter-vehicle communication or the like. The forward vehicle information includes information on the position, vehicle speed, vehicle type (large vehicle or other vehicle), and vehicle identification ID for the forward vehicle. Then, based on the acquired forward vehicle information, the vehicle type of the forward vehicle is determined. Specifically, the vehicle ahead (the position of the vehicle ahead) is mapped to the navigation (map information) of the host vehicle, and the vehicle type is determined from the difference between the current value and the previous value of the position information for the same vehicle. The vehicle to be determined is an oncoming vehicle on the travel path of the host vehicle, and other vehicles. Other vehicles include, for example, vehicles on other routes, vehicles traveling in the same direction, stopped vehicles, and the like. The vehicle type can also be determined using the relationship between the traveling direction of the host vehicle and the traveling direction of the preceding vehicle. When it is determined by this vehicle type determination that the preceding vehicle is an oncoming vehicle on the traveling path of the host vehicle, the oncoming vehicle (the position of the oncoming vehicle) is displayed on the navigation screen.

  Subsequently, in step S10, the passing estimation in the curve section is performed. Specifically, when it is determined in step S9 that there is an oncoming vehicle (when it is determined that the vehicle type of the preceding vehicle is an oncoming vehicle), the oncoming vehicle and the host vehicle are set in the curve section set in step S4. Judge whether or not each other passes. If it is determined in step S9 that there is no oncoming vehicle, step S10 and the subsequent step S11 are skipped and the process proceeds to step S12. The determination of passing is performed as follows, for example. This will be described with reference to FIGS. FIG. 7 schematically shows the host vehicle and the oncoming vehicle traveling on a curve. Further, FIG. 8 associates each value described below with each of the own vehicle and the oncoming vehicle traveling in a curve. Note that the passing determination may be performed by a method other than the passing determination described below.

First, the intrusion time and exit time of the own vehicle into the curve section are calculated. In the calculation, first, the intrusion time Tas is calculated by the following equation (8).
Tas = La / Va (8)
Here, Va is the host vehicle speed. Further, La is the distance from the current position of the host vehicle to the start node point of the curve section. Subsequently, using the intrusion time Tas calculated by the equation (8), the target node point calculated in the step S6, and the allowable lateral acceleration Yglmit set in the step S7, the exit time (curve exit) by the following equation (9): Arrival time) Tae is calculated.
Tae = Tas + Lra / Vra
= Tas + Lra / (Yglimit · | R _n |) ^1/2 (9)
Here, Vra is the target vehicle speed in the curve section. Lra is the distance from the start node point of the curve section to the end node point of the curve section.

Next, the entry time and exit time of the oncoming vehicle into the curve section are calculated. In the calculation, first, the intrusion time Tbs is calculated by the following equation (10).
Tbs = Lb / Vb (10)
Here, Vb is the vehicle speed of the oncoming vehicle. Lb is the distance from the current position of the host vehicle to the entrance of the curve section. Here, regarding the oncoming vehicle, the entrance of the curve section is the exit of the curve section regarding the host vehicle, that is, the end node point. Subsequently, using the intrusion time Tbs calculated by the equation (10), the target node point calculated in the step S6 and the allowable lateral acceleration Yglmit set in the step S7, the exit time (curve exit) by the following equation (11): Arrival time) Tae is calculated.
Tbe = Tbs + Lrb / Vrb
= Tbs + Lrb / (Yglimit · | R _n |) ^1/2 (11)

Here, Vrb is the target vehicle speed in the curve section. Lrb is the distance from the start node point of the curve section to the exit of the curve section. Here, regarding the oncoming vehicle, the exit of the curve section is the entrance of the curve section regarding the host vehicle, that is, the start node point. Therefore, the distance Lrb is the same as the distance Lra related to the host vehicle (Lrb = Lra).
Then, based on the intrusion time Tas and exit time Tae to the curve section of the own vehicle and the intrusion time Tbs and exit time Tbe to the curve section of the oncoming vehicle calculated by the above expressions (8) to (11), It is determined whether the vehicle and the oncoming vehicle pass each other in a curve section.

  FIG. 9 shows a processing procedure for the determination. As shown in FIG. 9, first, in step S31, the intrusion time Tas into the curve section of the host vehicle and the intrusion time Tbs into the curve section of the oncoming vehicle are compared. Based on the comparison, the later intrusion time is set to Tslate (Tslate = Max (Tas, Tbs)). That is, of the own vehicle and the oncoming vehicle, the entry time of the vehicle that enters the curve section later is set to Tslate. For example, as shown in FIG. 8, consider a case where the intrusion time of the host vehicle into the curve section is 5 seconds and the intrusion time of the oncoming vehicle into the curve section is 6 seconds. In this case, the intrusion time (5 seconds) of the host vehicle that enters the curve section later is set to Tslate.

  Subsequently, in step S32, the exit time of the curve section of the vehicle not selected in step S31 is set to Tefirst. The exit time of the curve section of the vehicle that has not been selected in step S31 is the exit time of a vehicle that quickly enters the curve section among the host vehicle and the oncoming vehicle. For example, in the case shown in FIG. 8, the leaving time (10 s) of the oncoming vehicle that enters the curve section early is set to Tefirst.

  In step S33, the value Tslate set in step S31 is compared with the value Tfirst set in step S32. If the value Tefirst is equal to or greater than the value Tslate (Tefrst ≧ Tslate), the process proceeds to step S34. In step S34, it is estimated that the host vehicle and the oncoming vehicle pass each other in a curve section. This means that if the exit time of a vehicle that has entered the curve section early from the opposite side does not arrive within the intrusion time until the vehicle enters the curve section later, the vehicle will This is because it means to pass in the curve section. If the value Tefirst is less than the value Tslate (Tefrst <Tslate), the process proceeds to step S35. In step S35, it is estimated that the own vehicle and the oncoming vehicle do not pass each other in the curve section. This means that if the exit time of a vehicle that has entered the curve section early from the opposite side of the vehicle comes within the intrusion time until the vehicle enters the curve section later, the vehicle is delayed. This is because it means that a vehicle that has entered the curve section earlier from the opposite side of the vehicle exits the curve section before entering the curve section.

If it is determined in step S9 that there are a plurality of oncoming vehicles, the passing determination in the curve section is performed in step S10 for all the oncoming vehicles. In this case, when it is determined that the vehicle passes by a plurality of oncoming vehicles in the curve section, the nearest oncoming vehicle is selected.
In step S11, the allowable lateral acceleration value is corrected. If it is determined in step S10 that there is no oncoming vehicle passing in the curve section, the process proceeds to the subsequent step S12 without performing the correction process in step S11. In step S11, the allowable lateral acceleration value Yglimt set in step S7 is corrected in consideration of the influence of the oncoming vehicle. Specifically, the allowable lateral acceleration value Yglimt is corrected (updated) by the following equation (12).
Yglimit = Yglimit · Ky (12)

  Here, Ky is a coefficient corresponding to the influence of the oncoming vehicle. Specifically, the coefficient Ky changes according to the vehicle type of the oncoming vehicle and the presence or absence of the center line. Here, the vehicle type information is acquired through inter-vehicle communication or infrastructure equipment. Further, information on the presence or absence of the center line is acquired by navigation, road-to-vehicle communication, a camera mounted on the host vehicle, or the like. FIG. 10 shows an example of the coefficient Ky. As shown in FIG. 10, the coefficient Ky is larger in the other vehicles than in the large vehicle and the other vehicles. Further, the coefficient Ky has a larger value when the center line is present when the center line is present and when the center line is absent.

Subsequently, in step S12, a target vehicle speed is calculated. Specifically, the target vehicle speed Vr is calculated by the following equation (13) using the turning radius R _n of the target node point and the allowable lateral acceleration Yglimt.
Vr = (Yglimt · | R _n |) ^1/2 (13)
Here, the allowable lateral acceleration Yglimt is the allowable lateral acceleration Yglimt after the correction if the correction is performed in step S11.

Subsequently, in step S13, a target deceleration for automatic deceleration control is calculated. Automatic deceleration control is deceleration control that is performed before entering the curve section set in step S4. In step S13, by using the distance L _n of vehicle speed V calculated in step S2, the target vehicle speed Vr and the current position calculated in the step S12 to the start node point of the curve section, the target by the following equation (14) Deceleration Xgs is calculated.
Xgs = (V ² −Vr ² ) / (2 · L _n )
= (V ² −Yglimt · | R _n |) / (2 · L _n ) (14)

Here, the target deceleration Xgs has a positive value on the deceleration side. According to this equation (14), in relation to the allowable lateral acceleration Yglimt, the target deceleration Xgs decreases as the allowable lateral acceleration Yglimt increases. Further, the target deceleration Xgs decreases as the distance L _n to the start node point of the curve section increases. Further, as will be described later, the control operation flag Fgensoku is turned OFF in the curve section. That is, the automatic deceleration control ends immediately before the host vehicle enters the curve section. For this reason, the target deceleration Xgs for automatic deceleration control is a value that sufficiently decelerates the host vehicle immediately before the curve section so that the host vehicle can stably travel in the curve section.

Subsequently, in step S14, an alarm activation start determination is made. Specifically, using the target deceleration Xgs calculated in step S13, the alarm activation start determination is performed according to the following equations (15) and (16).
Alarm inactive state (when Fwarn = OFF)
Xgs ≧ Xgswarn (15)
Alarm activated state (when Fwarn = ON) +
Xgs ≧ Xgswarn−Khwarn (16)

  Here, Xgswarn is an alarm start determination set value. The alarm start determination set value Xgswarn is a fixed value, for example, 0.08 g. Fwarn is a flag indicating an alarm operating state. The alarm activation flag Fwarn is turned on when the expression (15) or the expression (16) is established, and is turned off when both the expressions (15) and (16) are not established. Khwarn is hysteresis for preventing hunting of alarm ON / OFF. As a result, the warning operation flag Fwarn is turned ON when the expression (15) or the expression (16) is established before the curve section. In the curve section, the alarm activation flag Fwarn is normally turned off. Khwarn is a fixed value, for example, 0.03 g.

Subsequently, in step S15, the control operation start determination of the automatic deceleration control is performed. Specifically, using the target deceleration Xgs calculated in step S13, the control operation start determination is performed according to the following equations (17) and (18).
When control is not activated (when Fgensoku = OFF)
Xgs ≧ Xgsstart (17)
During control operation (when Fgensoku = ON)
Xgs ≧ Xgsstart−Khstart (18)

  Here, Xgsstart is a control start determination setting value. The control start determination setting value Xgsstart is a fixed value, for example, 0.15 g. Fgensoku is a flag indicating the operating state of control. The control operation flag Fgensoku is turned on when the expression (17) or the expression (18) is established, and is turned off when both the expressions (17) and (18) are not established. Khstart is a hysteresis for preventing hunting of control ON / OFF. Khstart is a fixed value such as 0.05 g. Thereby, the control operation flag Fgensoku is turned ON when the expression (17) or the expression (18) is established before the curve section. In the curve section, the control operation flag Fgensoku is normally turned off. Here, consider a case where the control start determination set value Xgsstart is set to a value larger than the alarm start determination set value Xgswarn (Xgsstart> Xgswarn). In this case, when the target deceleration Xgs increases, in the process, the alarm activation flag Fwarn is turned on, and then the control activation flag Fgensoku is turned on.

Subsequently, in step S16, a target brake hydraulic pressure for each wheel is calculated. Specifically, first, the control target hydraulic pressure Pc is calculated by the following equation (19) using the target deceleration Xgs calculated in step S13.
Pc = Kb · Xgs (19)
Here, Kb is a constant determined from brake specifications and the like. Then, using the control target hydraulic pressure Pc, the front wheel target braking fluid pressure Psfr and the rear wheel target braking fluid pressure Psrr are calculated by the following equations (20) and (21).
Psfr = Max (Pm, Pc) (20)
Psrr = h (Psfr) (21)

  Here, the function h is a function for calculating the hydraulic pressure of the rear wheels from the hydraulic pressure of the front wheels so that the optimal front / rear braking force distribution is obtained. Pm is a master cylinder hydraulic pressure (Pmf, Pmr) obtained by a braking operation by the driver. Therefore, according to the equations (20) and (21), when the master cylinder hydraulic pressure Pm is larger than the control target hydraulic pressure Pc, the target braking hydraulic pressures Psfr and Psrr corresponding to the master cylinder hydraulic pressure Pm become. That is, the target braking fluid pressures Psfr and Psrr corresponding to the braking operation by the driver are obtained.

Subsequently, in step S17, the driving force of the driving wheel is calculated. Specifically, using the accelerator opening θt read in step S1, the control target hydraulic pressure Pc calculated in step S16, and the control operation flag Fgensoku, the target drive is performed according to the following equations (22) and (23). Torque Trqds is calculated.
When the control operation flag Fgensoku = ON, Trqds = f (θt) −g (Pc) (22)
When control operation flag Fgensoku = OFF Trqds = f (θt) (23)

  Here, the function f is a function for calculating the target drive torque in accordance with the accelerator opening degree θt. The function g is a function for calculating an estimated braking torque generated by the control target hydraulic pressure Pc. According to equation (22), if automatic deceleration control is being performed (Fgensoku = ON), the target drive torque Trqds is calculated by subtracting the braking torque generated by the automatic deceleration control. That is, even if the driver performs the accelerator operation, the engine output is reduced. Further, according to equation (23), if automatic deceleration control is not performed (Fgensoku = OFF), engine output is performed in accordance with the driver's accelerator operation. Thus, while the automatic deceleration control is operating, the target drive torque Trqds is calculated according to the accelerator opening θt and the control amount of the automatic deceleration control. Further, when the automatic deceleration control is not in operation, the target drive torque Trqds is calculated according to the accelerator opening θt.

  In step S18, a control signal is output. Specifically, a control signal is output to the brake fluid pressure control unit 7 and the drive torque control unit 12 according to the target brake hydraulic pressure Psi calculated in step S16 and the target drive torque Trqds calculated in step S17. In addition, the alarm monitor 31 performs an output for warning the driver by display, sound, or buzzer.

(Operation and action)
Operation and action are as follows.
While the vehicle is running, various data are acquired from each sensor or the like (step S1), and the vehicle speed V is calculated (step S2). Further, the turning radius of each node point is calculated based on the coordinates of each node point read as the forward road information (step S3). Then, based on the calculated turning radius of each node point, a curve section is specified (step S4). Further, the road surface μ estimated value Kμ is calculated based on the relationship between the braking / driving force acting on each wheel and the slip generated on each wheel (step S5). Then, based on the road surface μ estimated value Kμ, an allowable lateral acceleration Yglimt is set (step S7).

Further, the node point having the smallest turning radius of the latest curve is set as the target node point (step S6). Further, the presence / absence of a forward vehicle is detected (step S8), and if a forward vehicle is present, a forward vehicle determination process is performed (step S9). In the forward vehicle determination process, the forward vehicle information is acquired by inter-vehicle communication, and the vehicle type of the forward vehicle is determined based on the acquired forward vehicle information. When the preceding vehicle is an oncoming vehicle, the passing estimation is performed in the curve section between the oncoming vehicle and the host vehicle (step S10). If the estimation results in a difference between the host vehicle and the oncoming vehicle in the curve section, the allowable lateral acceleration value is corrected (step S11). Then, the target vehicle speed Vr is calculated using the turning radius R _n of the target node point and the uncorrected or corrected allowable lateral acceleration Yglimt (step S12).

  Then, a target deceleration Xgs for automatic deceleration control is calculated using the calculated target vehicle speed Vr and the like (step S13). Then, based on the target deceleration Xgs, an alarm operation start determination and a control operation start determination for automatic deceleration control are performed (steps S14 and S15). Further, based on the target deceleration Xgs, a target brake hydraulic pressure Psi for each wheel is calculated (step S16). Further, the target drive torque Trqds is calculated using the target brake hydraulic pressure Psi of each wheel as necessary (step S17). Then, a control signal is output to the brake fluid pressure control unit 7 and the drive torque control unit 12 according to the target brake fluid pressure Psi and the target drive torque Trqds. Thereby, automatic deceleration control by braking force control and driving force control operates. Further, the alarm monitor 31 performs an output for warning the driver by display, voice, or buzzer (step S18).

  In the above operation, when it is estimated that the oncoming vehicle and the curve section pass each other, the allowable lateral acceleration value Yglimt is corrected. Here, the allowable lateral acceleration Yglimt is calculated by the equation (7). Then, the calculated allowable lateral acceleration Yglimt is corrected by the equation (12). Specifically, when there is an oncoming vehicle that passes by a curve section, correction is made to reduce the allowable lateral acceleration Yglimt. When the oncoming vehicle passing in the curve section becomes a large vehicle and other vehicles, the allowable lateral acceleration Yglimt is corrected so that the large vehicle becomes smaller. As a result, when the vehicle passes by a large vehicle in a curve section, the allowable lateral acceleration Yglimt decreases, and thus the target deceleration Xgs increases (the above-described equation (14)). That is, when passing between a large vehicle and a curve section, the deceleration by automatic deceleration control increases. Further, the control start timing of the automatic deceleration control is advanced (the above formulas (17) and (18)). Further, the control start timing of the alarm output control is also advanced (the above formulas (15) and (16)).

  Further, the allowable lateral acceleration Yglimt is corrected according to the presence or absence of the center line of the curve section. Specifically, when there is no center line in the curve section, the allowable lateral acceleration Yglimt is corrected to be smaller. As a result, when the host vehicle travels in a curve section having no center line, the allowable lateral acceleration Yglimt decreases, and thus the target deceleration Xgs increases (the above-described equation (14)). That is, when the host vehicle travels in a curve section without a center line, the deceleration due to automatic deceleration control increases. Further, the control start timing of the automatic deceleration control is advanced (the above formulas (17) and (18)). Further, the control start timing of the alarm output control is also advanced (the above formulas (15) and (16)).

Further, when the large vehicle and the curve section pass each other and there is no center line in the curve section, the allowable lateral acceleration Yglimt shows a minimum value.
Further, the automatic deceleration control and the alarm output control are started and ended before the host vehicle enters the curve section as long as the expressions (15) to (18) are satisfied. That is, automatic deceleration control and alarm output control are completed before the host vehicle enters the curve section.
This embodiment can also be realized by the following configuration.
That is, in this embodiment, automatic deceleration control and alarm output control are cited as control for the curve while corresponding to the oncoming vehicle traveling in the curve section. On the other hand, the control for the curve may be other control while corresponding to the oncoming vehicle traveling in the curve section.

In this embodiment, both the control amount and the control start timing are changed according to the presence or absence of the oncoming vehicle. On the other hand, only one of the control amount and the control start timing can be changed.
In this embodiment, the control amount and the control start timing are changed according to the size of the oncoming vehicle. On the other hand, the control amount and the control start timing can be changed according to the vehicle width of the oncoming vehicle and the road width of the curve section. Specifically, the control amount is increased, for example, the deceleration of the automatic deceleration control is increased as the difference between the vehicle width of the oncoming vehicle and the road width of the curve section is reduced. Further, the control start timing is advanced, for example, the control start timing of the automatic deceleration control is advanced as the difference between the vehicle width of the oncoming vehicle and the road width of the curve section becomes smaller. Here, the road width information of the curve section is obtained from, for example, a navigation system. Further, the vehicle width of the oncoming vehicle is estimated from the vehicle size information obtained for the oncoming vehicle.

  In this embodiment, steps S8 and S9 of the braking / driving force control unit 8 and the communication device 32 realize other vehicle information acquisition means for acquiring information of other vehicles. Further, the process of step S10 of the braking / driving force control unit 8 passes the own vehicle in the curve section based on the information of the other vehicle acquired by the other vehicle information acquisition means before the own vehicle enters the curve. An oncoming vehicle presence / absence determining means for determining the presence / absence of a possible oncoming vehicle is realized. Further, the processing of steps S11 to S18 (particularly step S11) of the braking / driving force control unit 8 corresponds to the oncoming vehicle traveling in the curve section when the oncoming vehicle presence / absence determining means determines that the oncoming vehicle is present. However, control means for controlling the host vehicle corresponding to the curve is realized.

(effect)
The effect of this embodiment is as follows.
(1) Based on the information on the preceding vehicle acquired before the host vehicle enters the curve, it is possible to determine whether there is an oncoming vehicle that may pass the host vehicle in the curve section. Furthermore, when it is determined that there is an oncoming vehicle, it is possible to control the host vehicle corresponding to the curve while corresponding to the oncoming vehicle traveling in the curve section. Here, automatic deceleration control and alarm output control are performed. Thereby, even when information about the oncoming vehicle can no longer be obtained, it is possible to appropriately control the oncoming vehicle while considering the road shape in front of the host vehicle. Thereby, automatic deceleration control and warning output control that do not give the driver a sense of incongruity can be realized.

(2) In automatic deceleration control, when the host vehicle passes by an oncoming vehicle in a curve section, the deceleration increases and the control start timing is advanced. In this way, automatic deceleration control for the curve can be realized while corresponding to the oncoming vehicle traveling in the curve section.
(3) Automatic deceleration control and warning output control are performed based on the size of the oncoming vehicle. Accordingly, automatic deceleration control and warning output control can be performed according to the size of the oncoming vehicle while corresponding to the oncoming vehicle that may pass the own vehicle in the curve section.

(4) When the oncoming vehicle is large, the deceleration by the automatic deceleration control is made larger, and the control start timing is advanced. As a result, the automatic deceleration control and the alarm output control can give the driver a sense of security even when passing a large vehicle while traveling in a curve section.
(5) Automatic deceleration control and alarm output control are performed based on the presence or absence of the center line of the curve section passing by the oncoming vehicle. Accordingly, automatic deceleration control and alarm output control can be performed in accordance with the presence or absence of the center line of the curve section while corresponding to an oncoming vehicle that may pass the host vehicle in the curve section.

(6) When there is no center line, the deceleration by the automatic deceleration control is made larger and the control start timing is advanced. Thereby, automatic deceleration control and alarm output control can give the driver a sense of security even when traveling in a curve section without a center line.
(7) The automatic deceleration control and the alarm output control are completed before the host vehicle enters the curve section. Thereby, by carrying out automatic deceleration control and alarm output control within a straight section before the curve section, it is possible to maintain the stability of the behavior of the host vehicle and realize these controls.

(8) Information on the preceding vehicle is acquired by vehicle-to-vehicle communication or road-to-vehicle communication. In vehicle-to-vehicle communication and road-to-vehicle communication, highly accurate information can be obtained, but the communication area is limited. In this way, when using vehicle-to-vehicle communication or road-to-vehicle communication in which the communication area is limited, even when information about the oncoming vehicle can no longer be obtained, the oncoming vehicle is considered while considering the road shape ahead of the host vehicle. Can be appropriately controlled.
(9) As the difference between the vehicle width of the oncoming vehicle and the road width of the curve section becomes smaller, the deceleration of the automatic deceleration control is increased and the control start timing is advanced. In this way, automatic deceleration control can be performed in accordance with the relationship between the oncoming vehicle that may pass the host vehicle in the curve section and the road width.

It is a figure which shows the structure of the vehicle of embodiment of this invention. It is a flowchart which shows the process sequence of a braking / driving force control unit. It is the figure used in order to demonstrate the specific procedure of a curve area. It is another figure used in order to demonstrate the specific procedure of a curve area. It is a characteristic view showing the relationship between the host vehicle speed V and the allowable lateral acceleration calculation coefficient Ks. It is the figure used for description of the communication area of vehicle-to-vehicle communication. FIG. 5 is a diagram schematically illustrating a host vehicle and an oncoming vehicle that are used to explain values used in calculation and travel along a curve. It is used for explaining the values used in the calculation, and is another view schematically showing the host vehicle and the oncoming vehicle traveling on a curve. It is a flowchart which shows the process sequence of the passing determination in a curve area. It is a figure which shows an example of the coefficient Ky.

Explanation of symbols

  6FL to 6RR wheel cylinder, 7 brake fluid pressure control unit, 8 braking / driving force control unit, 9 engine, 12 drive torque control unit, 13 imaging unit, 14 navigation device, 16 radar, 17 master cylinder pressure sensor, 18 accelerator opening Sensor, 19 Steering angle sensor, 22FL to 22RR Wheel speed sensor, 31 Warning monitor, 32 Communication device

Claims (9)

Other vehicle information acquisition means for acquiring information of other vehicles;
Oncoming vehicle presence / absence determination that determines whether there is an oncoming vehicle that may pass the own vehicle in the curve section based on the information on the other vehicle acquired by the other vehicle information acquisition means before the own vehicle enters the curve Means,
If the oncoming vehicle presence / absence determining means determines that the oncoming vehicle is present, a control means for controlling the own vehicle corresponding to the curve while corresponding to the oncoming vehicle traveling in the curve section;
A vehicle travel control device comprising:   The control means performs deceleration control corresponding to a curve, and when the oncoming vehicle presence / absence judging means judges that the oncoming vehicle is present, a change to increase the deceleration of the deceleration control and the control of the deceleration control The vehicular travel control apparatus according to claim 1, wherein at least one of the changes to make the start timing earlier is performed.   The vehicle travel control apparatus according to claim 1, wherein the other vehicle information acquisition unit acquires a size of the other vehicle as information on the other vehicle.   The control means performs deceleration control corresponding to a curve, and the deceleration of the deceleration control increases as the size of the oncoming vehicle acquired by the other vehicle information acquisition means as information on the other vehicle increases. The vehicular travel control apparatus according to claim 3, wherein at least one of making a change to increase and advancing control start timing of the deceleration control is performed.   The said control means controls the own vehicle corresponding to a curve, corresponding to the oncoming vehicle which drive | works the said curve area based on the presence or absence of the center line of the said curve area. The vehicle travel control device according to any one of 4.   The control means performs deceleration control corresponding to a curve, and when the center line of the curve section is not present, the deceleration of the deceleration control is increased compared to the case of the center line of the curve section. The vehicle travel control apparatus according to claim 5, wherein at least one of a change to be made and a change to make the control start timing of the deceleration control earlier is performed.   The control means performs deceleration control corresponding to a curve, corresponds to an oncoming vehicle traveling in the curve section, and starts and ends the deceleration control before the own vehicle enters the curve. The vehicular travel control apparatus according to any one of claims 1 to 6.   8. The vehicle according to claim 1, wherein the other vehicle information acquisition unit acquires information of another vehicle through at least one of vehicle-to-vehicle communication and road-to-vehicle communication. Travel control device.   Before the host vehicle enters the curve, information on other vehicles is acquired. Based on the acquired information on the other vehicles, it is determined whether there is an oncoming vehicle that may pass the host vehicle in the curve section. When it is determined that there is an oncoming vehicle, the deceleration of the deceleration control of the own vehicle performed corresponding to the curve is increased according to the difference between the width of the oncoming vehicle and the road width of the curve section, and A vehicle travel control method characterized in that at least one of a deceleration control start timing is advanced.

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