JPH06297982A - Running controller for vehicle - Google Patents

Abstract

PURPOSE:To provide a running controller which is capable of following a preceding car without delay or sudden approach not only in running on a flat road but on a slope. CONSTITUTION:An inter-vehicle distance detected by a rader device 10 and a car speed detected by a car-speed sensor 12 are supplied to an ECU 14. The ECU 14 calculates a target driving force to follow a preceding car and controls a throttle actuator 16 or a brake actuator 18. When the ECU 14 calculates the target driving force, a virtual model vehicle is set which can follow the preceding car with a desired following characteristic, whether it is on a flat road or a slope, and an acceleration, car speed and running distance of the model vehicle is simulated. The target driving force is calculated using a high gain in order to exactly follow this model vehicle based on the acceleration, car speed and running distance obtained through calculation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle travel control device, and more particularly to a control device that keeps a vehicle-to-vehicle distance to a preceding vehicle at a predetermined distance and follows the preceding vehicle.

[0002]

2. Description of the Related Art Conventionally, various devices have been developed and installed for the purpose of reducing the driving operation of the driver and improving safety. The safe inter-vehicle distance is calculated from the running condition of the own vehicle. One of them is a travel control device that controls the own vehicle speed while keeping the following, and follows the preceding vehicle.

That is, the safe inter-vehicle distance (target inter-vehicle distance)
Ld is calculated from the vehicle speed V by Ld = pV + q, where p and q are calculated by constants, and the target driving force F of the vehicle required to reach the target inter-vehicle distance is F = M {k1 (L-Ld) + k2 Vr } Is calculated. Here, M is the mass of the vehicle, L is the inter-vehicle distance, Vr is the relative speed, and k1 and k2 are the inter-vehicle distance gain and the relative speed gain, respectively. Then, by comparing the target driving force F with the running resistance of the own vehicle, it is determined whether acceleration or deceleration is necessary, and the throttle actuator or the brake actuator is controlled to follow the preceding vehicle. The inter-vehicle distance gain k1 and the relative speed gain k
2 is determined from the viewpoint of improving the tracking accuracy, for example (k1
, K2 = 0.49, 0.64). The applicant of the present application previously applied for such a traveling control device in Japanese Patent Application No. 3-2.
Proposed in No. 64863.

[0004]

Under certain conditions, the following characteristics can be adjusted so as to match the driving feeling by appropriately adjusting these gains k1 and k2. That is, if the gain is increased, it is possible to follow the preceding vehicle even if the preceding vehicle suddenly accelerates, and if the gain is decreased, the vehicle is smoothly accelerated and follows the preceding vehicle. However, there is a problem in that the desired follow-up characteristic cannot be obtained with the target driving force F when some kind of disturbance such as a change in the road gradient or the vehicle weight is applied instead of under a constant condition.

That is, even if the target driving force F is calculated with the desired gains k1 and k2 in order to follow the preceding vehicle, for example, gravity acts on the vehicle on a slope road, and therefore, on an uphill road compared to a flat road. Driving force is reduced as compared with the target driving force, and the vehicle will follow with an acceleration smaller than the desired acceleration. Therefore, there may be a case where the vehicle cannot follow the preceding vehicle on a steep slope, and there is a possibility that the vehicle may approach the preceding vehicle abnormally on the descending road.

When the gain is large, the vehicle can follow the preceding vehicle while maintaining the target inter-vehicle distance, but since the own vehicle is frequently accelerated and decelerated, the occupant in the own vehicle has a bad driving feeling. Therefore, to improve the driving feeling,
It is desirable to reduce the gain. However, when the tracking gain of the host vehicle with respect to the preceding vehicle is small, the adjustment amount of the target driving force F is small with a slight change in the inter-vehicle distance. Therefore, for example, on an uphill road, the inter-vehicle distance must be longer than the target inter-vehicle distance. You may not be able to follow.

The state will be described using a motion equation.

From the weight M of the own vehicle, the acceleration A of the own vehicle, the target driving force F, and the running resistance force (including disturbance) f, the equation of motion MA = F-f is established. While the vehicle is traveling on an uphill road, a force acts downward on the vehicle along the slope, so that f is greater than on a flat road (f>
0). During constant speed follow-up traveling on an ascending slope, if A = 0, then F = f. F = M {k1 (L-Ld) + k2 Vr}, but since the relative speed Vr = 0 during constant speed follow-up traveling, (L-
Ld) ≠ 0. Therefore, the inter-vehicle distance L becomes larger than the target inter-vehicle distance Ld. Especially, when the value of the gain k1 is small, L becomes larger than Ld. On the downhill, on the contrary, L may be smaller than the target inter-vehicle distance Ld.

Of course, the vehicle is provided with a separate gradient sensor,
It may be possible to automatically adjust the gains k1 and k2 in the gradient road, but the device configuration becomes complicated and the gain k
There is also a problem that drivability deteriorates with changes in 1 and k2.

The present invention has been made in view of the above problems of the prior art, and its purpose is to follow a preceding vehicle with a desired following characteristic even in a situation where a disturbance such as a change in road gradient or vehicle weight is applied. An object of the present invention is to provide a vehicle travel control device capable of traveling.

[0011]

In order to achieve the above object, the vehicular travel control device of the present invention is designed to keep the inter-vehicle distance from a preceding vehicle at a predetermined target inter-vehicle distance and follow the preceding vehicle. In a vehicle travel control device for controlling a target driving force of an own vehicle, a vehicle speed detecting means for detecting an own vehicle speed, an inter-vehicle distance detecting means for detecting an inter-vehicle distance to a preceding vehicle, and a relative speed to the preceding vehicle are detected. Relative speed detection means, calculation means for calculating acceleration and vehicle speed required to follow the preceding vehicle with desired tracking characteristics based on the target vehicle distance, detected vehicle distance and relative speed, and the acceleration and vehicle speed. And a control unit that feedback-controls the driving force of the own vehicle with a high gain so as to obtain the traveling distance.

[0012]

In the vehicle travel control device according to the present invention, an ideal model vehicle that can follow the preceding vehicle with desired tracking characteristics is set virtually regardless of whether it is on a flat road or a slope road.
The driving force is feedback-controlled with a high gain so that the own vehicle follows the model vehicle exactly.

Here, the acceleration, vehicle speed and mileage of the virtually set model vehicle are calculated based on the inter-vehicle distance and relative speed with respect to the preceding vehicle and the target inter-vehicle distance so as to have desired follow-up characteristics. Even under the road, the acceleration, the vehicle speed, and the traveling distance are calculated without being affected by the gravitational acceleration.

Therefore, by controlling the vehicle speed of the own vehicle so as to obtain the acceleration, vehicle speed and mileage of the model vehicle thus virtually set, as a result, the desired following characteristic of the preceding vehicle can be obtained even under disturbance. It becomes possible to follow with.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of a vehicle traveling apparatus of the present invention will be described below with reference to the drawings. FIG. 1 shows a block diagram of the configuration of this embodiment. The radar device 10 is mounted at a predetermined position of the vehicle, and the inter-vehicle distance from the preceding vehicle is detected. A millimeter wave radar, a laser radar, or the like can be used as the radar device 10. The detected inter-vehicle distance data with the preceding vehicle is supplied to the electronic control unit ECU 14, and the inter-vehicle distance data is time-differentiated to calculate the relative speed data. On the other hand, a vehicle speed sensor 12 is also provided to detect the own vehicle speed and supply it to the ECU 14. The ECU 14 is configured to calculate the target driving force of the own vehicle based on the inter-vehicle distance data, the relative speed data, and the vehicle speed data, control the throttle actuator 16 to the brake actuator 18, and follow the preceding vehicle.

Here, when calculating the target driving force, the ECU 14 sets a virtual model vehicle that follows the preceding vehicle with desired following characteristics, and determines the acceleration required for this model vehicle.
Calculate vehicle speed and mileage. Then, the target driving force is calculated so that the host vehicle travels at the acceleration, the vehicle speed, and the traveling distance. FIG. 2 shows a conceptual diagram of processing in the ECU 14. A virtual model vehicle 300 (shown by a broken line in the figure) having a desired tracking characteristic is set for the preceding vehicle 100, and a vehicle-to-vehicle distance L13 between the preceding vehicle 100 and this model vehicle 300 and a target vehicle-to-vehicle distance Ld (vehicle speed). Calculated based on
Based on the above, the acceleration a3, the vehicle speed V3 and the mileage d3 required for the model vehicle 300 are simulated. The model vehicle 300 is a vehicle that can follow the preceding vehicle 100 with desired tracking characteristics under any disturbance, for example, on a steep road. Then, the vehicle speed of the host vehicle 200 is controlled by performing high gain feedback control so as to follow the model vehicle 300 exactly. Virtual model vehicle 30
0 has a desired follow-up characteristic and can follow the preceding vehicle 100 under any disturbance with a desired driving feeling. As a result, the host vehicle 200 can also follow the preceding vehicle 100 under any disturbance. .

FIG. 3 schematically shows the control contents of the ECU 14 of this embodiment in more detail. For convenience of explanation, each variable is defined as follows.

V1: vehicle speed of preceding vehicle V2: vehicle speed of following vehicle (own vehicle) V3: ideal vehicle speed of following vehicle (virtual model vehicle) L12: distance between preceding vehicle and following vehicle L13: preceding vehicle and ideal vehicle Distance between following vehicles L23: Distance between ideal following vehicle and following vehicle d2: Distance traveled by following vehicle from time t = 0 d3: Distance traveled by ideal following vehicle from time t = 0 a3: Ideal following vehicle Acceleration Ld: Target inter-vehicle distance F: Target driving force required for the following vehicle In FIG. 3, the vehicle speed V1 of the preceding vehicle 100 is calculated from the vehicle speed V2 of the following vehicle (own vehicle) and the relative speed Vr.
And the ideal following vehicle 300 by integrating the difference in vehicle speed V3 between the preceding vehicle 100 and the ideal following vehicle 300.
Is calculated. On the other hand, the target inter-vehicle distance Ld is calculated using the constants p and q based on the vehicle speed V2 of the following vehicle 200, and L13 is calculated as L13.
And Ld is calculated. And this preceding vehicle 100
And the ideal following vehicle 300 distance L13 and target distance Ld
And the vehicle speed V1 of the preceding vehicle 100 and the ideal following vehicle 300
Of the desired gains k1 and k based on the difference between the vehicle speed V3 and the relative speed between the preceding vehicle 100 and the ideal following vehicle 300.
The acceleration a3 required for the ideal following vehicle 300 is calculated using 2. That is, the acceleration a3 of the ideal following vehicle 300
Is a3 = k1 (L13-Ld) + k2 (V1-V3).

In this way, the acceleration a3 of the ideal following vehicle 300 is calculated, and the ideal following vehicle 30 at the next control time is calculated.
A vehicle speed V3 of 0 is obtained by integrating this acceleration a3. Then, the inter-vehicle distance L23 between the ideal following vehicle 300 and the following vehicle 200 is calculated by integrating the difference between the vehicle speed V3 of the ideal following vehicle 300 and the vehicle speed V2 of the following vehicle 200. Then, the acceleration a required for the ideal following vehicle 300
3, the following distance L23 between the ideal following vehicle 300 and the following vehicle 200, and the relative speed V3 between the ideal following vehicle 300 and the following vehicle 200 −
Based on V2, the target driving force F is calculated by F = M {a3 + k3.L23 + k4 (V3-V2)} using high gains k3 and k4 so as to follow the ideal following vehicle exactly. This target driving force F causes the following vehicle 200
By controlling the throttle and brake of (the own vehicle), the following vehicle 200 follows the ideal following vehicle 300 exactly, while the ideal following vehicle 300 has the desired following characteristic with respect to the preceding vehicle 100 under any disturbance. In order to follow, the following vehicle 200 can eventually follow the preceding vehicle 100 at a desired acceleration and under any disturbance.

The ECU 14 calculates the target driving force F based on such control contents and controls the vehicle speed of the vehicle.

The processing procedure will be specifically described below with reference to the flowchart of FIG.

The control cycle in this embodiment is 32 msec.
Is set to. First, the own vehicle speed V2 and the preceding vehicle 100
The inter-vehicle distance L12 is measured (S101). Own vehicle speed V
2 is detected by the vehicle speed sensor 12, and the inter-vehicle distance L12 is detected by the radar device 10. The index i is used to indicate that the data is data in the current control cycle.
Is used. The acceleration a3 required for the ideal following vehicle 300 (model vehicle) is calculated based on the measured own vehicle speed V2 and the inter-vehicle distance L12. In order to calculate the acceleration a3,
First, the traveling distance d2 of the host vehicle, the vehicle speed V1 of the preceding vehicle 100, the inter-vehicle distance L23 between the model vehicle and the own vehicle, and the inter-vehicle distance L13 between the preceding vehicle 100 and the model vehicle 300 are calculated (S10).
2). The traveling distance d2 of the own vehicle is obtained by adding the control time Δt and the own vehicle speed V2 to the traveling distance d2 up to the previous time. Further, the vehicle speed V1 of the preceding vehicle 100 is the relative speed obtained by time-differentiating the inter-vehicle distance from the preceding vehicle 100 and the own vehicle speed V2.
Calculated from The inter-vehicle distance between the model vehicle and the own vehicle is calculated from the running distance d3 of the model vehicle and the running distance d2 of the own vehicle. The running distance d3 of the model vehicle is obtained by integrating the previously calculated acceleration a3 of the model vehicle twice over time. Can be calculated. Furthermore, the preceding vehicle 100 and the model vehicle 300
The inter-vehicle distance L13 is calculated from the inter-vehicle distances L12 and L23 between the preceding vehicle 100 and the own vehicle 200. Further, the vehicle speed V3 of the model vehicle is calculated by time-integrating the acceleration a3 of the previous model vehicle. On the other hand, the target inter-vehicle distance L with the preceding vehicle 100
d is calculated by Ld = p.V2 + q using constants p and q. After L13, Ld, V1 and V3 are calculated in this way, the ECU 14 calculates the acceleration a3 required for the model vehicle based on these variables (S103). The acceleration a3 is, as described above, a3 [i] = a1 (L13 [i] -Ld [i]) + k2
It is calculated by (V1 [i] -V3 [i]). Note that the gains k1 and k2 at this time are
Places emphasis on tracking accuracy, for example (k1, k2 = 0.49,
0.64).

Then, the sign of the acceleration a3 thus calculated is determined (S104), and the acceleration a3 is negative,
That is, in the case of deceleration control, the control is performed with the acceleration a3 set with emphasis on tracking accuracy, while the acceleration a3
Is positive, that is, when acceleration is required, the gains k1 'and k2' should be set in order to perform control with emphasis on brake timing.
A3 [i] = K1 '(L13 [i] -Ld [i]) + k2
'(V1 [i] -V3 [i]). Note that k1 'and k2' are, for example, (k1 ', k2
′) = (0.10, 0.80) is set.

In this way, the acceleration a3 required for the model vehicle 300 is calculated, and the vehicle speed V3 and the traveling distance d3 required for the model vehicle 300 are calculated using this acceleration a3.
Is calculated. That is, the vehicle speed V3 is obtained by time integration of the acceleration a3, and the traveling distance d3 is calculated by further time integration of the calculated vehicle speed V3 (S106). And
Using these acceleration a3, vehicle speed V3, and traveling distance d3, the target driving force F of the own vehicle is set so as to follow the model vehicle 300 exactly. That is, the target driving force F is the gain k
Using 3 and k4, F [i] = M {a3 [i] + k3.L23 [i] + k4
(V3 [i] -V2 [i])}. The gains k3 and k4 are set to high gains, for example, (k3, k4) = (1.0, 3.4).
6) is set. The target driving force F is the model vehicle 30.
It is a driving force that can exactly follow the acceleration of 0, the vehicle speed, and the traveling distance, and the target driving force F is used to control the throttle or the brake (S108).

As described above, in the present embodiment, the throttle or brake of the own vehicle is controlled so as to firmly follow the model vehicle capable of following the preceding vehicle with a desired following characteristic by high gain feedback, so that the preceding vehicle is also performed on the slope road. You can follow the car reliably.

Further, since the target driving force F in this embodiment is determined by the high gains k3 and k4, the drivability is not deteriorated as compared with the case where two kinds of control gains are used, and hunting or the like is caused. Nor.

In the case of a diesel engine, follow-up control can be performed by controlling the fuel supply amount,
Further, not only the engine control but also the transmission may be controlled.

[0028]

As described above, according to the vehicle travel control device of the present invention, even if a disturbance such as the influence of gravity on a grade road occurs, the vehicle can smoothly follow the preceding vehicle with a desired follow-up characteristic. You can follow.

[Brief description of drawings]

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

FIG. 2 is a conceptual diagram of control in the same embodiment.

FIG. 3 is an explanatory diagram of control contents in the embodiment.

FIG. 4 is a processing flowchart of an ECU in the embodiment.

[Explanation of symbols]

 10 radar device 12 vehicle speed sensor 14 ECU 16 throttle actuator 18 brake actuator

Claims (1)

[Claims] 1. A vehicle traveling control device for controlling a target driving force of a vehicle so as to follow the preceding vehicle while maintaining a vehicle-to-vehicle distance between the vehicle and a preceding vehicle at a predetermined target vehicle-to-vehicle distance, and detecting a vehicle speed of the vehicle. A detection means, an inter-vehicle distance detection means for detecting an inter-vehicle distance to the preceding vehicle, a relative speed detection means for detecting a relative speed with respect to the preceding vehicle, and a preceding vehicle based on the target inter-vehicle distance, the detected inter-vehicle distance and the relative speed. A calculation unit that calculates the acceleration and the vehicle speed required to follow the vehicle with a desired tracking characteristic, and a control unit that feedback-controls the driving force of the own vehicle with a high gain in order to obtain the acceleration, the vehicle speed, and the mileage. A travel control device for a vehicle, comprising: