JP2013226945A - Vehicle traveling control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an implementation method of safe and superior energy utilization efficiency in transition to preceding vehicle tracking travel of a vehicle during single traveling and the tracking travel or braking travel after the transition.SOLUTION: A tracking travel area is set between a subject vehicle and a preceding traveling vehicle. A determination of right or wrong of transition from a normal traveling state of a vehicle to the tracking travel area by the inertia travel is normally repeated until a tracking travel transition becoming acceptable in a normal travel fixed time or each certain traveling distance, and the tracking travel area transition travel by the inertia travel is done from the point that became a tracking travel acceptable transition aiming at the tracking travel area. After the transition to the tracking travel area, tracking travel is performed by alternately repeating transition to moderate acceleration travel or inertia travel, each time when the following distance in the tracking travel area is expanded or reduced to a boundary following distance. When coming off from the tracking travel area by the speed variation etc. of the preceding vehicle, the subject vehicle increases the transition operation or the vehicle deceleration degree to the tracking travel area from the inertia travel deceleration to braking deceleration again and decelerates and stops.

Description

The present invention relates to a vehicle traveling control method (following traveling to the front vehicle and braking traveling control method) that makes the most of the kinetic energy of the vehicle for energy saving of vehicle traveling and reduction of exhaust gas amount.

As an appropriate follow-up driving control method for the preceding vehicle, the minimum inter-vehicle distance and the maximum inter-vehicle distance with the preceding vehicle are set according to the speed of the host vehicle, and the inter-vehicle distance with the preceding vehicle is smaller than the minimum inter-vehicle distance. In some cases, coasting is started, and when the inter-vehicle distance becomes greater than the maximum inter-vehicle distance, the generation of driving force is started, thereby maintaining the inter-vehicle distance with the preceding vehicle from the minimum inter-vehicle distance to the maximum inter-vehicle distance and A method of performing efficient follow-up traveling with a small amount of exhaust gas has been proposed (Patent Document 1).

However, in the above method, the control method at the time of transition from the constant speed traveling to the following traveling is not clear, and even during the following traveling, the inertial traveling or the driving force generation traveling is started under the above-mentioned inter-vehicle distance condition. However, depending on the relative speed with the preceding vehicle at the time of starting coasting or generating driving force, the inter-vehicle distance to the preceding vehicle is shorter than the minimum inter-vehicle distance described in Patent Document 1 or longer than the maximum inter-vehicle distance. As a result, there is a problem that the fluctuation range of the inter-vehicle distance becomes large.

As a solution to the problem of increasing the inter-vehicle distance fluctuation range in the above-mentioned follow-up running, a follow-up running area set by the own vehicle-front vehicle relative speed allowable range and the own vehicle-forward vehicle inter-vehicle distance range between the own vehicle and the preceding vehicle And a method of following the vehicle ahead by repeating the transition from inertial running to slow acceleration running or from the slow acceleration running to inertial running alternately in the following running region (patent). Reference 2).

However, in the method disclosed in Patent Document 2, there are unclear points in the method for setting the following traveling region and the method for dealing with the case where the host vehicle deviates from the following traveling region due to the speed fluctuation of the preceding vehicle.

Here, coasting means stopping the vehicle driving force generation operation of the engine, motor, etc., or stopping the vehicle driving force, such as the engine, motor, etc., from being transmitted to the drive wheels. This is a traveling method in which a vehicle travels only with the kinetic energy that is present.

JP2007-291919A JP2011-005920A

The invention of the present application is a method for safely and efficiently shifting to follow-up without braking after a vehicle running at a constant speed detects a preceding vehicle, ensuring a safe inter-vehicle distance after shifting to follow-up to the preceding vehicle, and Follow-up driving method that keeps the relative speed range with the preceding vehicle within a predetermined range while keeping the inter-vehicle distance fluctuation range to a minimum, and energy-saving driving when the relative speed range with the preceding vehicle or the inter-vehicle distance range exceeds the predetermined range, and We propose a rational response method from the viewpoint of safe driving.

The energy-saving performance of the engine / motor hybrid vehicle is that the kinetic energy of the vehicle is regenerated by the regenerative braking at the time of deceleration, and the regenerated energy is effectively and efficiently used at the start and acceleration. However, the kinetic energy regeneration efficiency of the vehicle during deceleration is far from 100%. Therefore, the most efficient method of using the kinetic energy possessed by the vehicle during deceleration is not to regenerate and use the kinetic energy, but to use it directly for vehicle travel, that is, by performing inertial travel using kinetic energy. is there.

In the vehicle travel control method according to the present invention, in the transition from the constant speed travel to the follow-up travel and the execution of the follow-up travel after the transition, the acceleration is performed as slowly as possible, and the deceleration is performed as much as possible except in the case of safety. The brakes (including regenerative brakes) are not used, and the vehicle is slowly decelerated by coasting that makes the best use of the kinetic energy of the vehicle.

First, the following traveling region setting method according to the present invention when a vehicle traveling at a speed Vs detects a forward vehicle traveling at a speed Va (provided that Vs> Va) at a point of a forward distance L, the following traveling A region transition method and a traveling method after transition to the following traveling region will be described with reference to FIG.

In FIG. 1, the own vehicle 11 has a safe inter-vehicle distance L1 (Va) represented by (Equation 1) determined by a forward vehicle speed Va and a maximum deceleration (braking deceleration) αm with respect to a forward vehicle 12 traveling at a speed Va. Car-front vehicle allowable relative speed maximum value Vr0 and inertial traveling deceleration αi determined by equation (2), inertial traveling distance maximum value L2 (Vr0), own vehicle-front vehicle allowable relative speed maximum value Vr0 and slow acceleration traveling Follow-up set by the slow acceleration maximum travel distance L3 (Vr0) expressed by (Equation 3) determined by the acceleration αa and the relative speed allowable range expressed by (Equation 4) (where relative velocity Vr = Va−Vs). After setting the traveling region 13 and starting inertial traveling at the inertial traveling deceleration αi from the present time when the host vehicle is traveling at the inter-vehicle distance L and the subject vehicle speed Vs, the relative speed Vr with respect to the preceding vehicle is Vr. When the vehicle becomes = 0, the predicted distance between the vehicle ahead It is calculated and determined whether or not the distance L ′ satisfies (Equation 5). Here, the predicted inter-vehicle distance L ′ is calculated by (Equation 6).

However, the follow-up travel area 13 includes an inertia follow-up travel area 14 set in a relative speed range of (Equation 4) and an inter-vehicle distance range of (Equation 8), a relative speed range of (Equation 4), and (Equation 9). It consists of a slow acceleration following travel region 15 set in the inter-vehicle distance range. The inter-vehicle distance indicated by (Equation 10) serving as the boundary between the inertia following traveling region 14 and the slow acceleration following traveling region 15 is referred to as a boundary inter-vehicle distance 16.

(Equation 1)
^{L1 (Va) = Va 2 /} (2 · αm)
Here, strictly speaking, (Equation 1) is L1 (Va) = Va ²
/(2.multidot..alpha.m)+L0 (L0: safe inter-vehicle distance when the vehicle ahead is stopped). In order to simplify the description, L1 (Va) will be expressed by (Equation 1).

(Equation 2)
L2 (Vr0) = Vr0 ² /(2.αi)

(Equation 3)
L3 (Vr0) = Vr0 ² /(2.αa)

(Equation 4)
-Vr0 ≤ Vr ≤ + Vr0

(Equation 5)
L1 (Va) ≤L'≤L1 (Va) + L2 (Vr0) + L3 (Vr0)

(Equation 6)
L ′ = L− {Vr0 ² /(2.αi)}

(Equation 7)
L1 (Va) ≤L≤L1 (Va) + L2 (Vr0) + L3 (Vr0)

Here, the safe inter-vehicle distance L1 (Va) is the minimum inter-vehicle distance at which the host vehicle traveling following the preceding vehicle traveling at the speed Va can safely stop at the emergency maximum deceleration αm.
The inertial running distance L2 (Vr0) is determined until the host vehicle running at the relative speed Vr = + Vr0 with the preceding vehicle running at the speed Va shifts to the inertial running at the deceleration αi and then becomes the relative speed Vr = 0. Relative mileage approaching the vehicle ahead,
The slow acceleration travel distance L3 (Vr0) is set to the relative speed Vr = 0 after the host vehicle traveling at a relative speed Vr = −Vr0 with respect to the preceding vehicle traveling at the speed Va shifts to the acceleration travel at the slow acceleration αa. Relative mileage away from the vehicle ahead,
It is.

If the predicted inter-vehicle distance L ′ satisfies (Equation 5) as a result of the determination, the vehicle starts inertial traveling toward the following traveling region, assuming that the vehicle can reach the following traveling region by inertial traveling from the present time. To do.
If the predicted inter-vehicle distance L ′ does not satisfy (Equation 5), the vehicle speed Vs at that time will be a fixed time Ti or a fixed travel distance Di.
After traveling, the distance L between the vehicle, the host vehicle speed Vs, and the forward vehicle speed Va are detected again, and the following traveling area is set using the above (Equation 1) to (Equation 6), inertial traveling. The determination of whether or not the vehicle can reach the following traveling region is repeated until the following traveling region can be reached, and then inertial traveling toward the following traveling region is started.

When the vehicle-to-front vehicle relative speed Vr becomes Vr = 0 after the start of inertial traveling toward the following traveling region, the vehicle-to-front vehicle distance L satisfies (Expression 6) or When the vehicle-forward vehicle relative speed Vr satisfies (Equation 3) when the vehicle-to-front vehicle distance L satisfies (Equation 10), it is assumed that the vehicle has entered the follow-up travel region, finish.

Next, when the transition to the follow-up running is completed as described above, if the distance L between the host vehicle and the preceding vehicle satisfies the equation (8), the inertia running at the deceleration αi is continued.
Further, when the distance L between the host vehicle and the preceding vehicle satisfies (Equation 9) at the time when the transition to the follow-up traveling is finished, the transition to the slow acceleration traveling of the slow acceleration αa is performed.

That is, in the follow-up running region 13 after the transition to the follow-up running, the following distance L during the inertia running through the state in which the inertial running relative speed Vr is Vr = 0 in the inertia following follow-up region 14 is shown in (Expression 10). When the distance (boundary inter-vehicle distance) is increased or the relative speed Vr is reduced to the speed shown in (Equation 11), the inertial running is changed to the slow acceleration running with the slow acceleration αa.
In addition, the following inter-vehicle distance L from the state of (Equation 9) through the state where the relative speed Vr during the slow acceleration traveling in the slow acceleration following traveling region 15 is Vr = 0 is changed to the distance (boundary inter-vehicle distance) shown in (Equation 10). When the reduction or the relative speed Vr increases to the speed shown in (Equation 12), from the slow acceleration running to the inertia running with the deceleration αi,
Migrate each.
As described above, when the vehicle distance L reaches the boundary inter-vehicle distance alternately by shifting to the inertia following traveling region 14 and the slow acceleration following traveling region 15, the vehicle can save energy without sudden acceleration, sudden deceleration, or braking. In addition, it is possible to perform follow-up traveling corresponding to a safe front vehicle traveling speed.

(Equation 8)
L1 (Va) ≦ L <L1 (Va) + L2 (Vr0)

(Equation 9)
L1 (Va) + L2 (Vr0) <L ≦ L1 (Va) + L2 (Vr0) + L3 (Vr0)

(Equation 10)
L = L1 (Va) + L2 (Vr0)

(Equation 11)
Vr = -Vr0

(Equation 12)
Vr = + Vr0

If the following distance L does not satisfy (Equation 8) and (Equation 9) when the relative speed Vr with the preceding vehicle reaches Vr = 0 during follow-up traveling, that is, (Equation 13) or (Equation 14).
Are satisfied, the following processing is performed on the assumption that the vehicle has deviated from the following traveling area due to fluctuations in the forward vehicle speed Va or the like.

(Equation 13)
L <L1 (Va)

(Equation 14)
L> L1 (Va) + L2 (Vr0) + L3 (Vr0)

If the relative speed Vr becomes Vr <-Vr0 due to sudden acceleration of the vehicle ahead during follow-up, or if the inter-vehicle distance satisfies (Equation 14), the follow-up travel region is set again between the vehicle and the vehicle ahead. It is set and it is determined whether or not the own vehicle can follow the preceding vehicle. If yes, a transition process to the following traveling region is performed to shift to the following following traveling. If the follow-up traveling is not possible, the vehicle shifts to constant speed traveling at the set speed Vc.

On the other hand, during follow-up, the vehicle in front suddenly decelerates or stops suddenly and the relative speed becomes Vr.
If> + Vr0, or if the inter-vehicle distance satisfies (Equation 13), the deceleration α is calculated from (Equation 15), and the host vehicle follows the deceleration traveling at the calculated deceleration α. Continue until you return to the area or until your vehicle stops.

(Equation 15)
α = Vr ² / (2 · L) (where α ≦ αm)

In the above description, the deceleration αi during coasting is constant, but actually varies depending on the vehicle state (travel speed, vehicle weight, etc.) or the road condition (road gradient, road surface condition, etc.). This correction can be performed by, for example, storing and holding the deceleration correction coefficient for each vehicle state and road state in a map database of a car navigation system mounted on the vehicle and using it, or measuring it during coasting. .

According to the present invention, on a general road or an exclusive road for automobiles, it is possible to safely shift to follow-up after detecting a preceding vehicle, continue to follow-up after transition to follow-up, and respond to changes in the front vehicle speed during follow-up. It can be carried out efficiently and can greatly contribute to energy saving, reduction of exhaust gas emissions and safe driving regardless of whether the vehicle has an energy regeneration function.

Basic concept explanatory diagram of the following traveling and the following traveling region according to the present invention, ACC (Adaptive Cruise Control) device functional configuration example of the present invention, It is an example of the travel control procedure by this invention.

The present invention can be basically implemented by improving an ACC (Adaptive Cruise Control) apparatus. Further, instead of or in addition to the radar function which is one of the components of the conventional ACC device, there is a method of providing a vehicle position specifying function such as a high-accuracy GPS receiver and a vehicle-to-vehicle communication function.
A first embodiment of the present invention using a radar-type ACC device will be described below as a first embodiment.

An example of the radar system ACC device functional configuration is shown in FIG. 2, and an example of a traveling control procedure in the arithmetic control unit 22 in FIG. 2 is shown in FIG.
In FIG.
20 is an ACC device composed of a radar 21 and an arithmetic control unit 22;
21 is a radar that detects a relative speed Vr of the preceding vehicle with respect to the own vehicle-front vehicle distance L and the own vehicle speed Vs;
Reference numeral 22 denotes information on the distance L between the host vehicle and the preceding vehicle, which is an output of the radar 21, relative speed Vr information of the preceding vehicle with respect to the host vehicle speed Vs, host vehicle speed Vs information obtained from the host vehicle, and host vehicle traveling set by the driver. Based on the travel control presence / absence information indicating whether or not to perform automatic travel control, the set speed Vc information during constant speed travel, the speed control information for traveling the vehicle, and the vehicle driving / braking / inertial traveling control information are driven. Calculation control unit that outputs to force output mechanism, driving force transmission mechanism, braking control mechanism,
It is.

FIG. 3 shows an automatic travel control procedure in the arithmetic control unit in FIG. 2, that is, a control procedure for constant speed travel, transition to follow-up travel, follow-up travel control, and braking control.
However, as a background process of the control procedure process shown in FIG. 3, the own vehicle speed Vs, the distance L to the preceding vehicle, the relative speed Vr between the own vehicle and the preceding vehicle (provided that Vr> 0 when the own vehicle-the preceding vehicle is approaching, It is assumed that Vr <0 is continuously measured while the host vehicle is moving away from the vehicle ahead.

In FIG.
301 is the starting point of the travel control procedure,
302 is an automatic travel control start determination process for determining whether or not there is an instruction on whether or not to start the automatic travel control from the driver;
303 is a front vehicle presence / absence determination process for determining whether or not there is a vehicle ahead in the range of the radar detection distance after determining that there is an automatic travel control instruction in process 302;
304 is a forward vehicle speed determination process for determining whether or not the forward vehicle speed Va (= Vs−Vr) is less than the constant speed traveling speed Vc of the own vehicle;
305 is a constant speed traveling process for causing the host vehicle to travel at a constant speed traveling speed Vc preset in the ACC device,

306 is a follow-up running area setting process for setting the follow-up running area shown in FIG. 1 between the own vehicle and the preceding vehicle when it is determined in process 304 that the preceding vehicle is running at a speed lower than the own vehicle set speed Vc.
307 is a follow-up travel transition determination that determines whether or not the vehicle has shifted from the current travel state to inertial travel and can travel to the follow-up travel region set in the process 306, that is, whether or not the vehicle can travel following the vehicle ahead. processing,
If it is determined in the process 307 that it is not possible to make a transition to follow-up, whether the relative speed Vr in the follow-up running region is Vr> Vr0 or whether the inter-vehicle distance L is L <L1 is the cause. From the abnormal approach determination process to the front vehicle to determine the abnormal approach to the vehicle ahead of the vehicle,
309 determines an abnormal distance from the vehicle ahead of the vehicle based on whether or not the relative speed Vr in the following traveling region is Vr <−Vr0 or whether the inter-vehicle distance L is L> L1 + L2 + L3. Abnormal distance determination processing from the vehicle ahead,

310 is a follow-up travel transition process for performing a follow-up travel transition by coasting when it is determined in the process 307 that a follow-up travel transition is possible;
311 is a follow-up travel region transition completion determination process for determining whether or not the own vehicle has been transferred to the follow-up travel region as a result of the follow-up travel transition processing by the processing 310;
When it is determined that the host vehicle is in an abnormal approaching state (out of the following traveling region) as a result of processing 308, 312 is decelerated at a deceleration of α = Vr ² / (2 · L). Decelerating running control processing to control,

313 and 314, when it is determined in the process 311 that the own vehicle has been transferred to the following traveling region, the inertia determining whether the current own vehicle position is the inertia traveling region in the following traveling region or the slow acceleration region. Traveling region determination processing and slow acceleration region determination processing,
315 is a vehicle stop determination process for determining whether or not the vehicle speed Vs is Vs = 0, that is, whether the vehicle is stopped as a result of the process 312;
If it is determined that the host vehicle has stopped as a result of the process 315, the travel control process ends once and waits for the next control instruction, or waits for the start of travel.
317 is an inertial traveling process in the following traveling region in which the inertial traveling is performed when it is determined as a result of the processing 313 that the vehicle is in the inertial traveling region;
318 is a slow acceleration running process in a follow-up running area that performs slow acceleration running when it is determined that the vehicle is in the slow acceleration running area as a result of process 314;
319 is a slow acceleration travel transition determination process for determining whether or not the current inertial travel state should be shifted to the slow acceleration travel based on the success or failure of the inter-vehicle distance L ≧ L1 + L2.
320 is an inertial travel transition determination process for determining whether or not the current slow acceleration travel is to be shifted to inertial travel from the success or failure of L ≦ L1 + L2.
It is.

With the control described above, safe driving that requires less braking than conventional follow-up driving or decelerating driving, results in less energy consumption and exhaust gas, and can respond to sudden speed changes in the vehicle ahead. Is possible.

As described above, according to the vehicle travel control method of the present invention, the transition of the vehicle during normal traveling to the preceding vehicle to smooth and efficient follow-up traveling, and the stable, safe and efficient following after the transition to following vehicle traveling is performed. It is possible to cope with a case where traveling and follow-up traveling become impossible, in particular, a reasonable and safe handling process for deceleration / stop of the preceding vehicle, which has a great effect on vehicle energy saving, emission gas reduction, and safe driving.

11: Own vehicle 12: preceding vehicle 13: following traveling region 14: inertia following traveling region 15: slow acceleration following traveling region 16: boundary inter-vehicle distance

L: Distance between own vehicle and forward vehicle Vs: own vehicle speed,
Va: vehicle speed ahead,
Vr: Relative speed between the preceding vehicle and the host vehicle (Vr> 0: when approaching, V <0: when moving away),
Vr0: own vehicle-front vehicle allowable relative speed maximum value,
L1 (Va), L1: Safe vehicle-to-vehicle distance corresponding to forward vehicle speed Va = Va ² /(2.αm)
Αm: Maximum deceleration for deceleration travel,
L2 (Vr0), L2: self-vehicle-front vehicle allowable relative speed maximum value Vr0 corresponding to the inertial travel distance maximum value, inertial travel region inter-vehicle distance,
= Vr0 ² /(2.αi)
αi: coasting deceleration,
L3 (Vr0), L3: Own vehicle-front vehicle allowable relative speed maximum value Vr0 corresponding to the maximum value of the slow acceleration travel distance, the slow acceleration travel range inter-vehicle distance,
= Vr0 ² /(2.αa)
αa: slow acceleration, running acceleration,
L1 + L2: Boundary distance between vehicles
L ′: host vehicle-forward vehicle predicted inter-vehicle distance,

Claims (2)

Set between the own vehicle and the forward traveling vehicle with the allowable range of relative speed between the own vehicle and the preceding vehicle (-Vr0 ≤ Vr ≤ V0r) and the following distance between the own vehicle and the preceding vehicle traveling distance (L1 ≤ L ≤ L1 + L2 + L3). Forward vehicle speed by alternately repeating the transition from coasting to slow acceleration or from slow acceleration to coasting at a boundary inter-vehicle distance (L = L1 + L2) within the following traveling region. Follow-up driving corresponding to
The vehicle travel control method characterized by the above-mentioned.
here,
L: Distance between host vehicle and front vehicle Vr: Relative speed between front vehicle and host vehicle (Vr> 0: approaching, V <0: away)
Vr0: own vehicle-front vehicle allowable relative speed maximum value,
L1 (Va), L1: Safe vehicle-to-front vehicle-to-vehicle distance corresponding to the forward vehicle speed Va,
= Va ² /(2.αm)
αm: Maximum deceleration deceleration value,
L2 (Vr0), L2: self-vehicle-front vehicle allowable relative speed maximum value Vr0 corresponding to the inertial travel distance maximum value, inertial travel region inter-vehicle distance,
= Vr0 ² /(2.αi)
αi: coasting deceleration,
L3 (Vr0), L3: Own vehicle-front vehicle allowable relative speed maximum value Vr0 corresponding to the maximum value of the slow acceleration travel distance, the slow acceleration travel range inter-vehicle distance,
= Vr0 ² /(2.αa)
αa: slow acceleration, running acceleration,
L1 + L2: Boundary distance between vehicles
It is. When the inter-vehicle distance L becomes L <L1 or the relative speed Vr becomes Vr> Vr0 due to deceleration or stopping of the preceding vehicle, the deceleration α with respect to the preceding vehicle is expressed as α = Vr ² / (2. L) (where α ≦ αm)
Further, when the distance L between the vehicles becomes L> L1 + L2 + L3 due to acceleration of the preceding vehicle or when the relative speed Vr becomes Vr <−Vr0, it is determined whether or not the vehicle is allowed to shift to the follow-up travel region. Follow-up running transition processing or constant speed running processing corresponding to the result of
By doing each, return to follow-up driving, transition to constant speed driving, or stop,
The vehicle travel control method according to claim 1.