JPH04238742A - Running control device for vehicle - Google Patents

Abstract

PURPOSE:To provide a vehicle running control device whereby a distance between cars can be controlled suited for a condition matched with a flow of traffic even in the crowded condition such as running in the periphery of an urban district with a large amount of traffic. CONSTITUTION:Detection values of front and rear between-car distance sensors 7, 8 or the like are fed to a controller 3 in which a throttle valve 4 is controlled opened/closed so as to follow up a front vehicle by a target distance between cars. In a condition that a changing amount of the rear actual between-car distance between a following vehicle and a self car is larger than the preset, a target between-car distance relating to the front vehicle is changed short.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention relates to a forward distance detecting means for detecting the actual distance between the preceding vehicle and the own vehicle, a target following distance setting means in which a target following distance is set, and an actual forward distance between the vehicles. The present invention relates to a vehicle running control device having a control means for controlling the following distance so that the following distance becomes a target following distance, and in particular, the control means is configured to appropriately change the target following distance between the vehicle in front and the own vehicle according to the driving situation of the vehicle. The present invention relates to a vehicle travel control device.

0002

[Prior Art] In recent years, forward vehicle following control, also known as so-called inter-vehicle distance control, has become known for vehicles. In this control, the inter-vehicle distance between the vehicle in front and the own vehicle is detected using a sensor, etc. The detected actual distance between vehicles ahead is compared with a predetermined target distance between vehicles, and the driving state of the vehicle is controlled so that the actual distance between vehicles ahead becomes the target distance between vehicles. For example, Japanese Unexamined Patent Publication No. 61-6031 proposes a system that not only maintains the actual inter-vehicle distance to the vehicle in front at a target inter-vehicle distance, but also allows the target inter-vehicle distance to be adjusted.

0003

[Problem to be Solved by the Invention] By the way, in such inter-vehicle distance control, the minimum required inter-vehicle distance is the stopping distance at the current vehicle speed, and a certain amount of extra distance based on this is required to provide a margin. This is set as the target following distance, but in congested urban areas with a lot of traffic, for example, this could lead to vehicles cutting into the target following distance. In addition, in this case, the vehicle is forced to decelerate each time an intervening vehicle appears in order to maintain the target inter-vehicle distance, resulting in the inconvenience that smooth travel cannot be ensured.

The present invention was made in view of the above-mentioned background, and provides a vehicle that can promote smooth running suited to the situation without disturbing the flow of traffic even in heavy traffic situations such as when driving in a city. The purpose is to provide a travel control device for vehicles.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a forward distance detecting means for detecting the actual distance between the preceding vehicle and the own vehicle, and a target distance detecting means for detecting the actual distance between the preceding vehicle and the own vehicle. A rear inter-vehicle distance for detecting an actual rear inter-vehicle distance between a rear vehicle and one's own vehicle in a vehicle travel control device having a distance setting means and a control means for controlling the inter-vehicle distance so that the actual inter-vehicle distance in front becomes a target inter-vehicle distance. The present invention is characterized by providing a detection means and a target inter-vehicle distance correction means for changing the target inter-vehicle distance to a shorter value when the amount of variation in the rear actual inter-vehicle distance detected by the rear inter-vehicle distance detection means is larger than a set value. do.

[0006]

[Operation] With the above configuration, driving in a congested city area with a large amount of traffic is determined as a state in which the amount of change in the actual rear distance between the vehicle behind and the host vehicle is greater than the set value, and the system determines accordingly. , the target inter-vehicle distance is changed to be shorter by the target inter-vehicle distance correction means.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing a preferred embodiment of the present invention, in which a control system linked to an engine 1 mounted on a vehicle is shown. In this embodiment, a control system that combines constant speed driving control and inter-vehicle distance control is exemplified, and the basic configuration of the control is that when a preceding vehicle is not detected, constant speed driving control is prioritized, and On the other hand, when a vehicle ahead is captured, priority is given to inter-vehicle distance control.

[0008] A transmission 2 is connected to the output shaft of the engine 1, and the transmission 2 outputs rotational driving force to the propeller shaft according to the selected gear position. , each part is appropriately controlled by the controller 3.

The controller 3 is equipped with a so-called control computer, to which a large number of detection signals from various sensors are inputted in order to judge the running state of the vehicle, the operating state of the engine 1, and the like. That is, the controller 3 includes a throttle opening sensor 5 that detects the opening of the throttle valve 4 provided in the intake passage 10 of the engine 1.
, a vehicle speed sensor 6 that detects the output rotational speed from the transmission 2 as the vehicle speed, a front distance sensor 7 as a front distance detection means that detects the actual distance between the front vehicle and the vehicle in front, and an actual rear distance between the vehicle and the rear vehicle. , a rear inter-vehicle distance sensor 8 as a rear inter-vehicle distance detection means for detecting a rear inter-vehicle distance, an accelerator sensor 11 for detecting the depression of the accelerator 9, a brake switch 13 for detecting the depression of the brake 12, a rainy weather sensor 14 for detecting rainy weather, etc. A main switch 15 that starts constant speed driving control when a signal is input, and a set switch 16 that switches to constant speed driving control when operated by the driver and sets the vehicle speed at the time of the operation as a target vehicle speed.
, a coast switch 17 that instructs a deceleration command, and a resume switch 18 that instructs a return command to return control to the previously set target vehicle speed after operating the brake 12 or coast switch 17. A signal is input, and a control signal based on a predetermined control program is sent to a throttle actuator 19 that opens and closes the throttle valve 4, etc., and travel control is executed.

FIG. 2 is a flowchart schematically showing constant speed driving control, and FIG. 3 is a flowchart schematically showing a processing portion related to inter-vehicle distance control related to constant speed driving control. The control flow for constant speed driving shown in FIG. 2 is performed when the main switch 15 is ON, the target vehicle speed is set by operating the set switch 16, and the vehicle is already in a steady constant speed driving state, that is, autocruise. belongs to. When this auto cruise is in effect, the running load is first determined (S1), and then a condition is determined as to whether to continue or cancel the control (S2).
, S3). That is, when it is determined that the brake 12 is depressed (S2, YES) or when it is determined that the accelerator 9 is depressed (S3, YES), autocruise is canceled and normal control is returned. Here, if there is a depression operation on the brake 12 (S2, YES), a flag indicating the depression operation on the brake 12 is used as a flag for determining whether or not the operation determination of the resume switch 18 in the subsequent stage is performed. 1 is placed in SETF (S20). On the other hand, in other control states, auto cruise continues, and after these determinations, the set switch 16, coast switch 17, and resume switch 1 are activated.
8 operations are sequentially monitored (S4,
In addition to S5 and S7), the flag SETF described above and the flag COSTF described later are also monitored (S6).

When the set switch 16 is turned on (S4
, YES), the current vehicle speed VSP is stored as the target vehicle speed SETV (S40), and constant speed control is performed using the new target vehicle speed SETV (S8), but the ON operation of the set switch 16 continues for more than a predetermined time. If (S41, YE
S) Perform separate acceleration control (S9).

[0012] When the coast switch 17 is turned on, (S
5, YES), sends a control signal to the throttle actuator 19 to fully close the throttle valve 4 (S50), stores the decelerated current vehicle speed VSP as a new target vehicle speed SETV (S51), and switches the coast switch. 1
Set the flag COSTF indicating operation 7 to 1 (S
52).

[0013] Next, the process moves to the operation determination of the resume switch 18 (S7), but the return control operation by the resume switch 18 is
Alternatively, this is performed assuming a deceleration state due to the ON operation of the coast switch 17, and therefore, the determination of the flags SETF and COSTF described above is performed prior to the determination of the operation of the resume switch 18 (S6). Here, if either of these flags SETF and COSTF is 1 (S6, YES), it is assumed that deceleration control has been performed once, and return control is appropriate, and therefore the operation of the resume switch 18 is determined. (S
7). On the other hand, if both flags are 0, it is determined that there was no deceleration operation before (S6, NO
), constant speed control is executed without determining whether the resume switch 18 is operated (S8).

When the resume switch 18 is turned on (
S7, YES), sets the flag RESUF indicating the operation of this resume switch 18 to 1 (S70), until the vehicle speed VSP reaches the lower limit of the target vehicle speed SETV (vehicle speed in S40) before the operation of the brake 12 or coast switch 17. (S71, NO) Performs acceleration control (S71, NO)
9). Here, in the first loop, the control moves from S7 to S70, but in the second and subsequent loops, it is determined that the flag RESUF is 1 (S73, YES).
) control will flow. Then, when the lower limit value is exceeded (S71, YES), each flag RESUF, SET
Reset F to 0 (S72) and return to constant speed control (
S8). Note that if the resume switch 18 is not operated (S7 and S73, NO), the current control state will be maintained.

In the present embodiment, inter-vehicle distance control is combined with such constant speed running control. This inter-vehicle distance control is shown in FIG. 3, and is executed with priority over constant speed driving control when the forward inter-vehicle distance sensor 7 detects a vehicle in front.

At this time, a target inter-vehicle distance setting means in which a target inter-vehicle distance is set, a control means for controlling the inter-vehicle distance so that the actual forward inter-vehicle distance becomes the target inter-vehicle distance, and a rear inter-vehicle distance detected by the rear inter-vehicle distance sensor 8. The target inter-vehicle distance correction means that shortens the target inter-vehicle distance when the amount of variation in the actual inter-vehicle distance is larger than a set value is configured by a program set in the controller 3.

First, the sensor 7 checks whether or not the vehicle in front is captured, and the situation where the vehicle in front is not captured (S900) is determined.
, NO), the constant speed running control mode is entered, and at this time the control as described above is performed (S901).

On the other hand, in a situation where the preceding vehicle is detected by the sensor 7 (S900, YES), the vehicle-to-vehicle distance control mode is entered, and at this time, the target vehicle-to-vehicle distance TDIS is first set (S902 to S905).

The target inter-vehicle distance TDIS is a standard inter-vehicle distance set in order to follow the vehicle in front.
When the vehicle speed is high, the stopping distance also increases, so the target inter-vehicle distance TDIS is also set to be large, and in this way, the target inter-vehicle distance TDIS is determined with respect to the vehicle speed. To explain this graphically, as shown in Figure 4,
The target inter-vehicle distance TDIS is set larger as the vehicle speed increases, and the controller 3 has a so-called comparison table (map).
It is equipped with the following configuration. In particular, it is equipped with a steady map for when the road surface is dry and a rain map for when the road surface is wet, and the target inter-vehicle distance TDIS at the same vehicle speed is set larger in the rain map than in the steady map. be done. Therefore, the target inter-vehicle distance TDIS
In the setting, first check the detection value of the rain sensor 13 (S
902), if it is raining (S902, YES), input the rainy weather map (S903), and if it is not raining (S902), input the rainy weather map (S903).
02, NO) A steady map is input (S904), and a target inter-vehicle distance TDIS corresponding to the current vehicle speed is read out from any of the input maps (S905). After that, in general, a control gain is determined according to the driving situation of the vehicle (S906 to S910), and a control amount is determined from the deviation between the target inter-vehicle distance TDIS and the actual inter-vehicle distance DIS for inter-vehicle distance control. This is the throttle actuator 18
Processing such as sending the control signal as a control signal (S911) is performed. In this embodiment, inter-vehicle distance control (S911) is vehicle speed feedback control, and here control is performed based on a control gain (S910) determined according to the driving situation of the vehicle. Target inter-vehicle distance TDI set in this way
S is basically a control target value in inter-vehicle distance control, but in the present invention, this target inter-vehicle distance TDI
S is further corrected according to the amount of variation in the distance between the vehicle and the vehicle behind (S906 to S914), and after this,
Generally speaking, a control amount is obtained from the deviation between the normal target inter-vehicle distance TDIS or the corrected target inter-vehicle distance L and the actual forward inter-vehicle distance DIS, and this is sent as a control signal to the throttle actuator 19 (S915). Perform processing.

Originally, the target inter-vehicle distance TDIS is set (S908), but in this embodiment, it is changed depending on the vehicle speed and a variation index BU, which will be described later. That is, when the actual forward inter-vehicle distance DIS is larger than the target inter-vehicle distance TDIS (S906, YES), this target inter-vehicle distance T
DIS is directly used as the control target value when the vehicle speed of the own vehicle is equal to or higher than the set value V2 (S907, NO), and conversely, when the vehicle speed of the own vehicle is smaller than the set value V2 (S907
, YES), first obtain a variation index BU for the actual rear inter-vehicle distance RDIS between the rear vehicle and the own vehicle (S910
~S912), when this fluctuation index BU is larger than the allowable value IP (S913, YES), the target inter-vehicle distance TDIS
is corrected and made smaller, that is, the target inter-vehicle distance TDIS multiplied by a predetermined reduction rate ΔL is changed as a new target inter-vehicle distance (reduction value L), and this is set as the control target value (S9
14).

On the other hand, when the actual forward inter-vehicle distance DIS is smaller than the target inter-vehicle distance TDIS (S906, NO), the reason why the target inter-vehicle distance TDIS is used as the control target value is because the vehicle speed of the host vehicle is equal to or higher than the set value V1 (S909). , NO), and conversely, if the vehicle speed of the host vehicle is smaller than the set value V1 (S909, YES), first calculate the fluctuation index BU for the actual rear distance RDIS between the vehicle behind and the host vehicle ( S910 to S912), this fluctuation index BU is the tolerance value I
When the target inter-vehicle distance TDIS is larger than P (S913, YES), the target inter-vehicle distance TDIS is corrected to become smaller, that is, the target inter-vehicle distance TD
IS multiplied by a predetermined reduction rate ΔL is changed as a new target inter-vehicle distance (reduction value L), and this is set as the control target value (S914).

The fluctuation index BU is the amount of fluctuation ΔRDI in a unit period of the actual rear inter-vehicle distance RDIS between the rear vehicle and the host vehicle.
Specifically, the variation amount ΔRDIS, which is an absolute value, is calculated from the difference between the current rear actual inter-vehicle distance RDIS and the previous one (S910), and this variation amount ΔRDIS is calculated from the previous, A predetermined number of times n going back to the previous time is stored in a register string in the memory, but the stored values are shifted sequentially and the oldest one is discarded (S91
1) Find the sum of all the stored values of this register string and use this as the fluctuation index BU (S912).

Although the set values V1 and V2 regarding vehicle speed are set in advance, the set value V2 is slightly larger than the set value V1. For example, the set value V1 is set at 45 km/h, and the set value V2 is set at 50 km/h. h and the expected traveling speed in a situation with heavy traffic, such as when driving in a city area, are set. Here, in the vehicle speed determination described above, the two are crossed so to speak (
S907 and S909) and the determinations are superimposed, giving so-called hysteresis to the determinations, thereby preventing control hunting. Moreover, the reduction value L is
Although the target inter-vehicle distance TDIS is multiplied by a predetermined reduction rate ΔL to obtain a short inter-vehicle distance, the target inter-vehicle distance TDIS
It is not less than the stopping distance at each vehicle speed based on.

Here, when the vehicle speed is smaller than the set value V2 and the fluctuation index BU is larger than the allowable value IP, the control target value of the inter-vehicle distance control is changed to a reduction value L that is slightly shorter than normal, Such a situation in which the fluctuation index BU is large can be regarded as a situation in which the vehicle is congested and has a large amount of traffic, such as driving in a city. This setting state will be canceled and returned to the original target inter-vehicle distance TDIS if the vehicle speed increases to the set value V1 or higher or the fluctuation index BU falls below the allowable value IP, but it will continue until then. be done.

The present invention basically comprises a forward distance sensor 7 for detecting the actual forward distance DIS between the preceding vehicle and the own vehicle, a target inter-vehicle distance setting means in which the target inter-vehicle distance TDIS is set, and Inter-vehicle distance DIS is target inter-vehicle distance TD
In a vehicle travel control device having a control means for controlling an inter-vehicle distance so that the IS becomes IS, a rear inter-vehicle distance sensor 8 for detecting an actual rear inter-vehicle distance RDIS between the rear vehicle and the host vehicle is provided, and this rear inter-vehicle distance sensor In this embodiment, the controller 3 is configured to include a target inter-vehicle distance correction means for shortening the target inter-vehicle distance TDIS when the variation amount ΔRDIS of the rear actual inter-vehicle distance RDIS detected at step 8 is larger than a set value. As can be seen from the operation according to the above-described control flow shown in FIG.

[0026] According to such a configuration, a situation where the actual rear inter-vehicle distance RDIS between the rear vehicle and the own vehicle varies greatly, that is, the variation index BU is larger than the allowable value IP and there is a large amount of congested traffic, such as when driving in an urban area. In this situation, the controller 3 changes the target inter-vehicle distance TDIS to be slightly shorter, so the actual inter-vehicle distance in front DIS becomes slightly shorter, which makes it possible to suppress the triggering of cutting-in vehicles and to smoothly follow the vehicle in front, which is excellent in terms of safety. . In other words, even when there is heavy traffic around the city, the system can encourage smooth driving according to the traffic flow. In addition, the target inter-vehicle distance T
Even if the DIS is shortened, the distance is not less than the minimum required stopping distance as described above, so there is no need to worry about following the vehicle in front.

By the way, the fluctuation index BU is the fluctuation amount ΔRD
Instead of looking at the added value of IS over a predetermined period of time, for example, we can count the number of times that the vehicle behind has approached the set distance from the host vehicle for a predetermined number of times or more, and look at this over a predetermined period of time. In short, it is sufficient if the following status of the vehicle behind can be monitored, and the present invention is not limited to the above-mentioned embodiment in this respect.

[0028]

[Effects of the Invention] As explained in detail in the embodiments above, according to the vehicle travel control device according to the present invention, the target inter-vehicle distance is changed to a shorter value in crowded and heavy traffic conditions such as when driving in a city. , the actual distance between the vehicle in front and the own vehicle becomes slightly shorter, which prevents the vehicle from cutting in and allows for smooth follow-up, which improves safety. Furthermore, even in heavy traffic situations, the system can encourage smooth driving according to the flow of traffic.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart schematically showing constant speed driving control.

FIG. 3 is a flowchart schematically showing inter-vehicle distance control related to the control flow of FIG. 2;

FIG. 4 is a graph schematically showing the relationship between target inter-vehicle distance and vehicle speed.

[Explanation of symbols]

3 Controller 7 Front distance sensor 8 Rear distance sensor

Claims (1)

[Claims] [Claim 1] A forward inter-vehicle distance detection means for detecting the actual forward inter-vehicle distance between the preceding vehicle and the host vehicle, a target inter-vehicle distance setting means in which a target inter-vehicle distance is set, and the actual forward inter-vehicle distance becomes the target inter-vehicle distance. In a vehicle travel control device having a control means for controlling an inter-vehicle distance as shown in FIG. A vehicular travel control device comprising a target inter-vehicle distance correction means for changing the target inter-vehicle distance to a shorter value when the amount of variation in the actual rear inter-vehicle distance is greater than a set value.