JPH06328969A - Traveling control device for vehicle - Google Patents

Abstract

PURPOSE:To appropriately control the timing to start the deceleration of a vehicle by detecting the relative acceleration of the vehicle to a subject, and controlling the vehicle speed so as to obtain the target relative speed when the vehicle and the subject relatively approach to each other with the relative acceleration over the specified value. CONSTITUTION:A distance-between-vehicles detecting means 10 to detect the distance between a preceding vehicle and the subject vehicle and a vehicle speed detecting means 12 to detect the speed of the subject vehicle are provided, and the respective output signals are received by a control means 14. In this control means 14, the relative acceleration G and the relative speed are calculated based on the distance HW between vehicles, and the distance HW between vehicles is compared with the specified following distance HW1 between vehicles, and when HW>HW1, the opening of a throttle 22 is controlled through an actuator 18 to control the speed of the subject vehicle to a constant value. On the other hand, when HW<HW1, the relative acceleration G is compared with the specified positive value G1, and when G<G1 and when the subject vehicle and an object relatively approach to each other, the deceleration control is realized by a brake 20 so as to obtain the target relative speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle drive control device, and more particularly, to a vehicle for controlling the drive of the vehicle such that the vehicle follows the preceding vehicle or the vehicle so that the vehicle does not collide with an obstacle. Travel control device.

[0002]

2. Description of the Related Art Conventionally, as a follow-up running control device for controlling follow-up running of an automobile, the following distance between the preceding vehicle and the own vehicle is used, and the distance between the preceding vehicle and the own vehicle is a safe inter-vehicle distance. There is known a device for controlling the vehicle speed so as to achieve the following (Japanese Patent Laid-Open No. 61-77533). There is also known an inter-vehicle distance control device that changes the target inter-vehicle distance by using the acceleration of the preceding vehicle (Japanese Utility Model Laid-Open No. 2-13380). Further, there is known a device for controlling the vehicle speed by determining the target vehicle speed using the inter-vehicle distance between the preceding vehicle and the own vehicle, and correcting the target vehicle speed based on the relative acceleration (actual Kaihei 3
-295000 publication).

[0003]

However, in the conventional device for controlling the vehicle speed by the inter-vehicle distance and the relative speed, it takes time until the inter-vehicle distance and the relative speed change to a predetermined value with respect to deceleration of the preceding vehicle. That is, there is a problem that the responsiveness to the rapid deceleration of the preceding vehicle deteriorates. Therefore, the driver may feel that the start timing of deceleration of the vehicle is late.

Further, in the inter-vehicle distance control device for changing the target inter-vehicle distance by using the acceleration of the preceding vehicle, when the target inter-vehicle distance is changed to be short according to the positive acceleration of the preceding vehicle (the approaching direction is positive). The problem that the preceding vehicle causes a time delay until it reaches the target inter-vehicle distance, the responsiveness to the rapid deceleration of the preceding vehicle deteriorates, and the start timing of deceleration of the own vehicle is felt to be late as in the above case. There is a point. On the other hand, when the target inter-vehicle distance is changed according to the deceleration of the preceding vehicle, the responsiveness to the rapid deceleration of the preceding vehicle is improved, but the deceleration more than necessary is given.

Further, it is difficult for a driver to calculate an appropriate correction amount in a device that controls the vehicle speed by correcting the target vehicle speed on the basis of the relative acceleration, and appropriately controls the start timing of deceleration of the vehicle. Is difficult.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a vehicle travel control device in which the driver feels that the deceleration start timing is appropriate.

[0007]

In order to solve the above-mentioned object, the present invention relates to a relative acceleration detecting means for detecting the relative acceleration of an own vehicle with respect to an object, and the own vehicle and the object relative to each other at a relative acceleration of a predetermined value or more. Determination means for determining whether or not the vehicle and the object are relatively close to each other at a relative acceleration of a predetermined value or more so that the relative acceleration becomes equal to or less than a predetermined target relative acceleration. And a control means for controlling the vehicle speed.

[0008]

The principle of the present invention will be described below. The relative speed and the relative acceleration are positive in the directions in which the subject vehicle and the preceding vehicle approach each other. FIG. 4 shows analysis results of experiments conducted by the present inventors. The time from when the preceding vehicle starts approaching to when the following vehicle (self vehicle) starts decelerating and the relative distance between the preceding vehicle and the own vehicle. It shows the relationship with acceleration. As can be seen from the figure, when the relative acceleration is large (about 0.15 G or more), the time until the deceleration operation of releasing the foot from the accelerator pedal (throttle off) and stepping on the brake pedal (brake on) is started. That is, the time required to start deceleration is short at about 1 sec, and the driver immediately starts deceleration operation when the preceding vehicle or obstacle approaches and the relative acceleration at that time is large. In addition, FIG.
(2) shows the relationship between brake pressure and relative speed, and the relationship between brake pressure and relative acceleration over time. The position indicated by the arrow in the figure indicates the time point when the driver starts deceleration. As understood from the figure, when the relative acceleration is large, deceleration is started even though the relative speed between the preceding vehicle and the own vehicle is sufficiently small. That is, it can be understood that the driver immediately starts the deceleration operation when the relative acceleration is large even if the relative speed is small.

FIG. 6 shows an operation amount when a deceleration operation different from that shown in FIG. 5 is started. As can be understood from FIGS. 6A and 6B, the driver has a small relative acceleration A.
The holding of the brake pressure is started at the point, and the brake pressure is reduced at the point B where the relative acceleration is small and the relative speed is small.
That is, when the relative acceleration becomes a value that is sufficiently small with respect to the driver's detection characteristics, the driver stops applying the brake pressure and starts to hold the brake pressure, and the relative speed becomes sufficiently small with respect to the driver's detection characteristics. Holding the brake pressure is stopped to reduce the brake pressure. this is,
It is nothing but that the driver sets the relative acceleration as the control target during the emergency deceleration control. In addition, controlling the relative acceleration so that the driver has a sufficiently small value in the initial stage of deceleration means controlling the vehicle so that the same deceleration as that of the preceding vehicle is given to the vehicle first. It can be expected that there will be sufficient deceleration.
It should be noted that the fact that the brake pressure is not reduced even if the relative acceleration is sufficiently small as indicated by point A in FIG. 6B indicates that the control target is moving to the relative speed.

In the present invention, the actual driver determines the control target by the combination of the distance to the preceding vehicle or an object such as an obstacle, the relative speed, and the relative acceleration. The relative acceleration of 1 has the highest priority, and when the relative acceleration is high, the control is performed so as to immediately start deceleration even if the relative speed is low.

The relative acceleration detecting means of the present invention detects the relative acceleration of the host vehicle with respect to an object such as a preceding vehicle or an obstacle.
In order to detect the relative acceleration, the distance between the preceding vehicle and the object may be detected, and the relative acceleration may be obtained by differentiating this distance with respect to time. Alternatively, the relative speed between the own vehicle and the object may be calculated. The relative acceleration may be detected by detecting and differentiating this relative speed with respect to time. The determination means determines whether or not the own vehicle and the object are relatively close to each other with a relative acceleration of a predetermined value or more. When the vehicle and the object are relatively close to each other with a relative acceleration object having a predetermined value or more, the control means controls the vehicle speed so that the relative acceleration becomes equal to or less than a predetermined target relative acceleration.

In the present invention, the vehicle speed is controlled using the relative acceleration that is the control target of the driver during emergency deceleration, so the driver feels that the deceleration start timing is appropriate. As a result, it is possible to sensitively respond to a sudden change in the object, for example, a sudden change in the traveling state of the preceding vehicle, or a sudden change in the case where an obstacle suddenly falls in front of the own vehicle. Further, since the control target is the relative acceleration, unlike the conventional case where the target inter-vehicle distance is modified and changed, the deceleration operation equivalent to the deceleration operation of the preceding vehicle can be performed.

Further, according to the present invention, it is possible to quickly respond to an abrupt approach of an object by preferentially controlling the relative acceleration, and the relative velocity is controlled after the relative acceleration is controlled to be equal to or less than the target acceleration. By doing so, it is possible to give the driver a proper sense of deceleration without being decelerated more rapidly than necessary. Furthermore, by controlling the relative speed to the target relative speed and then controlling the distance to the object, the own vehicle can be surely prevented from colliding with the object.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. The present embodiment is an application of the present invention to a follow-up running control device that causes a host vehicle to run following a preceding vehicle. As shown in FIG. 1, this follow-up running control device includes an inter-vehicle distance detecting means 10 for detecting an inter-vehicle distance between a preceding vehicle and an own vehicle.
And vehicle speed detecting means 12 for detecting the speed of the vehicle (vehicle speed)
It has and. A laser range finder can be used as the inter-vehicle distance detecting means 10, and a speed sensor attached to the vehicle can be used as the vehicle speed detecting means 12. The inter-vehicle distance detecting means 10 and the vehicle speed detecting means 12 are composed of a microcomputer that calculates the relative speed and relative acceleration of the preceding vehicle and the own vehicle, and controls the own vehicle speed by controlling the brake pressure and the throttle opening. It is connected to the control means 14. This microcomputer has a CPU, a ROM and a RAM. This control means 14 is connected via an actuator 16 to a brake 20 provided in the vehicle, and the actuator 1
It is connected via 8 to a throttle 22 provided in the vehicle.

Next, the main routine of the control means 14 will be described with reference to FIG. This main routine is executed when the main switch of this device is turned on. In the following, the relative speed and the relative acceleration are positive when the own vehicle and the preceding vehicle approach each other.

In step 100, inter-vehicle distance detecting means 1
Current inter-vehicle distance HW detected at 0 and vehicle speed detection means 1
In step 102 as the relative acceleration detecting means, the current vehicle speed detected in 2 is taken, and the inter-vehicle distance HW is calculated.
The relative acceleration G and the relative velocity V are calculated based on In the next step 104, the inter-vehicle distance HW is compared with a predetermined follow-up inter-vehicle distance HW1, and when the inter-vehicle distance HW is larger than the follow-up inter-vehicle distance HW1, the own vehicle and the preceding vehicle are sufficiently separated from each other. In 106, as in the conventional constant-vehicle-speed auto drive, the opening of the throttle 22 is controlled via the actuator 18 so that the own-vehicle speed is controlled to be constant. On the other hand, when it is determined in step 104 that the inter-vehicle distance HW is equal to or less than the following inter-vehicle distance HW1, the following traveling control described below is executed.

Next, the following traveling control will be described. In step 108, the relative acceleration G is compared with a predetermined positive predetermined value G1, and when the relative acceleration G is less than or equal to the predetermined value G1, the relative speed V and the predetermined positive predetermined value V1 are determined in step 110. Compare. Step 110
When it is determined that the relative speed V is larger than the predetermined value V1 in step 112, the routine proceeds to step 112, and when the relative speed V is equal to or smaller than the predetermined value V1, in step 114 a reference value predetermined according to the vehicle speed and the current inter-vehicle distance HW. The difference ΔHW from the predetermined value H is determined according to this reference value.
It is determined whether or not it is smaller than Wc, and the difference ΔHW is a predetermined value HW.
When it is smaller than c, the routine proceeds to step 116. In step 116, the control target is the inter-vehicle distance to the preceding vehicle, and the own-vehicle speed is controlled so that the inter-vehicle distance corresponds to the reference value according to the own-vehicle speed. However, at this time, the brake is not controlled and the vehicle speed is controlled by controlling the throttle opening. On the other hand, when the difference ΔHW is greater than or equal to the predetermined value HWc, the process proceeds to step 112.

In step 112, the vehicle speed, the relative speed, and the deceleration start inter-vehicle distance Ldm stored in the ROM in advance.
From the table that defines the relationship between the vehicle speed and the relative speed V, the deceleration start inter-vehicle distance Ldm is calculated, and step 11
8, the deceleration start inter-vehicle distance Ldm and the current inter-vehicle distance H
When W is compared with W and the deceleration start inter-vehicle distance Ldm is equal to or less than the current inter-vehicle distance HW, the throttle opening is controlled in step 120 so that the engine brake is actuated to perform slow deceleration. In this slow deceleration, the current throttle opening may be held, or the holding of the throttle opening and the slow deceleration control may be combined depending on the size of the deceleration start inter-vehicle distance Ldm.

When it is determined in step 118 that the deceleration start inter-vehicle distance Ldm is greater than the current inter-vehicle distance HW, the control target is set to the inter-vehicle distance according to the own vehicle speed in step 122, and the vehicle decelerates with respect to a gradual approach. Take control. However, at this time, the throttle valve is fully closed and deceleration is adjusted only by the brake operation. Further, the deceleration degree at this time is different from the inter-vehicle distance control in step 116, and is 40 to 60 which is the deceleration degree in step 116.
It is preferable to set the value increased by%. This is because the control target used in the inter-vehicle distance control in step 116 is the ideal inter-vehicle distance that the driver normally feels to be optimum during follow-up travel, whereas the control target used in step 122 is the limit inter-vehicle distance that the driver dislikes further approaching. This is because it is a distance.

When it is determined in step 108 that the relative acceleration G is larger than the predetermined value G1, step 12
In step 4, deceleration control is performed. This deceleration control will be described in detail with reference to FIG. In step 130, the relative acceleration G and a predetermined value Go which is a predetermined sufficiently small positive value Go.
Compare with. The predetermined value Go is a value smaller than the predetermined value G1. When the relative acceleration G is equal to or larger than the predetermined value Go, the routine proceeds to step 132, and when the relative acceleration G is smaller than the predetermined value Go, the relative speed V is compared with the predetermined value Vo which is a predetermined small positive value in step 134. . When the relative speed V is equal to or higher than the predetermined value Vo, the routine proceeds to step 132, and when the relative speed V is smaller than the predetermined value Vo, in step 136, the inter-vehicle distance HW is compared with a predetermined minimum required safety inter-vehicle distance HWo. The vehicle-to-vehicle distance HW and the safe vehicle-to-vehicle distance HWo are compared here in order to further ensure safety. When the inter-vehicle distance HW is smaller than the safe inter-vehicle distance HWo in step 136, the routine proceeds to step 132, and when the inter-vehicle distance HW is equal to or greater than the safe inter-vehicle distance HWo, the routine proceeds to step 138, where the absolute value is a predetermined sufficiently small value and a negative predetermined value. Vm (<Vo) is compared with the relative speed V. Relative speed V
Is smaller than the predetermined value Vm, the routine proceeds to step 140, and when the relative speed V is equal to or larger than the predetermined value Vm, step 1
Proceed to 42. At step 132, the current brake pressure Br
The value obtained by adding a predetermined value ΔBrk to k is the new brake pressure B
The brake pressure Brk is increased by controlling the brake 20 via the actuator 16 as rk. As a result, when the relative acceleration G is equal to or greater than the predetermined value Go, the relative speed V is equal to or greater than the predetermined value Vo, and the inter-vehicle distance HW is less than the safe inter-vehicle distance HWo, the brake pressure Brk is increased and decelerated. become.

On the other hand, in step 140, the brake pressure Brk is reduced by controlling the brake 20 via the actuator 16 with the value obtained by subtracting the predetermined value ΔBrk from the current brake pressure Brk as the new brake pressure Brk. As a result, the relative acceleration G is smaller than the predetermined value Go,
When the relative speed V is smaller than the predetermined value Vo, the inter-vehicle distance HW is equal to or greater than the safe inter-vehicle distance HWo, and the relative speed V is smaller than the predetermined value Vm and the own vehicle and the preceding vehicle move away from each other, the brake pressure Brk is reduced. It In step 142, it is determined whether or not the brake pressure Brk is positive. If the brake pressure Brk is positive, the process returns to step 130, and if the brake pressure Brk is 0 or less, the process ends. Further, when the relative acceleration G is smaller than the predetermined value Go, the relative speed V is smaller than the predetermined value Vo, the inter-vehicle distance HW is the safe inter-vehicle distance HWo or more, and the relative speed V is the predetermined value Vm or more, the brake pressure Brk is Retained.

In the above description, the control means 14 calculates the relative acceleration G from the inter-vehicle distance HW detected by the inter-vehicle distance detecting means 10. However, the inter-vehicle distance and the relative speed are detected using a Doppler radar range finder or the like. The control means 14 may calculate the relative acceleration from the relative speed.

In the above description, an example in which a microcomputer is used as the control means 14 has been described, but a neural network including an input layer, an intermediate layer and an output layer may be used instead of the microcomputer. In this case, a neural network that inputs each data of the relative acceleration, the relative speed, the inter-vehicle distance, and the own vehicle speed to each neuron of the input layer and outputs the control target from the output layer is configured.
When the control of this device is not in operation (main switch is O
From the throttle and brake operation amount by the driver (in FF), it is determined what kind of control target the driver adopts at each time point, and the reference output is set.
The neural network is trained by inputting the relative speed, the inter-vehicle distance, and the vehicle speed. When adjusting the throttle opening (step 116 in FIG. 2), when both the throttle opening and the brake pressure are 0 (step 120 in FIG. 2), the driver's braking operation brings the inter-vehicle distance close to a value corresponding to the vehicle speed. When the vehicle is being controlled (step 122 in FIG. 2), the other braking (step 124 in FIG. 2) can be selected. This neural network may output four types of values with one output,
With two outputs, the presence or absence of ignition of the output unit may be assigned to 0 and 1 and expressed as a 2-bit value. Alternatively, one of the four outputs may be selected.

Further, although the example in which the present invention is applied to the follow-up running control device has been described above, the present invention can also be applied to a vehicle running control device such as an obstacle avoiding device for avoiding an obstacle during running. You can

[0025]

As described above, according to the present invention, since the vehicle speed is controlled on the basis of the relative acceleration, the driver can feel that the start of deceleration is appropriate.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing a main routine of control means.

3 is a flow chart showing details of step 124 of FIG.

FIG. 4 is a diagram showing a relationship between time until the vehicle starts decelerating and relative acceleration.

5 (1) and 5 (2) are diagrams showing the relationship between the brake pressure and the relative speed, and the relationship between the brake pressure and the relative acceleration, respectively.

6 (1) and 6 (2) are diagrams showing the relationship between the brake pressure and the relative speed, and the relationship between the brake pressure and the relative acceleration, respectively.

[Explanation of symbols]

 10 inter-vehicle distance detecting means 12 vehicle speed detecting means

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location F02D 29/02 K (72) Inventor Yoshikazu Hattori, Nagakute-cho, Aichi-gun, Aichi prefecture No. 1 Toyota Central Research Institute Co., Ltd. (72) Inventor Masashi Mizukoshi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Takashi Shigematsu 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd.

Claims (1)

[Claims] 1. Relative acceleration detecting means for detecting relative acceleration of the vehicle with respect to an object; determining means for determining whether or not the vehicle and the object are relatively close to each other at a relative acceleration of a predetermined value or more; Control means for controlling the vehicle speed so that the relative acceleration becomes equal to or less than a predetermined target relative acceleration (the approaching direction is positive) when the own vehicle and the object are relatively close to each other with a relative acceleration equal to or more than a value. A travel control device for a vehicle, including: