JP2003291686A - Preceding vehicle follow-up control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suitably perform follow-up travel control without giving a sense of incongruity to a driver even when traveling resistance by road gradient is varied. <P>SOLUTION: An inter-vehicle distance command value L* is calculated based on a preceding vehicle speed Vt by a basic inter-vehicle distance command value calculation part 31 based on an actual inter-vehicle distance L detected by a inter-vehicle distance sensor 1 and an own vehicle speed V detected by a vehicle sensor 2. When the road gradient is uphill, an corrected inter-vehicle distance command value L*' is calculated wherein the inter-vehicle distance command value L* is corrected to be extended based on a road gradient estimated value Sr estimated by a road gradient estimation part 38. A vehicle speed command value V* is calculated based on the corrected inter-vehicle distance command value L*' by a target inter-vehicle distance calculation part 33 and a vehicle speed command value calculation part 34. A driving force command value F* is calculated based on the vehicle speed command value V* by a vehicle speed control part 4. A throttle actuator 5 is controlled based on the driving force command value F*. Thus, follow-up travel control is performed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preceding vehicle follow-up control device which runs following a preceding vehicle, and more particularly to an optimum vehicle speed control on an uphill road.

[0002]

2. Description of the Related Art As a preceding vehicle follow-up control device of this type,
For example, Japanese Patent Application Laid-Open No. 2000-1359 previously proposed by the applicant.
The one described in Japanese Patent No. 34 is known. In this conventional example, the inter-vehicle distance command value is calculated based on the preceding vehicle speed, and the damping coefficient and the natural frequency of the inter-vehicle distance control system according to the inter-vehicle distance deviation and the relative speed are determined, and the vehicle speed command value is calculated. The target vehicle-to-vehicle distance and the target relative speed are calculated from the vehicle-to-vehicle distance command value using the filter defined by the damping coefficient and the natural frequency, and the vehicle speed detection value, the relative speed detection value, the vehicle-interval distance detection value, the target vehicle-to-vehicle distance Further, there is described a preceding vehicle follow-up control device which obtains a desired inter-vehicle distance response in various follow-up scenes by calculating a vehicle speed command value based on the target relative speed.

[0003]

However, in the above-mentioned conventional example, by determining the response characteristic of the inter-vehicle distance control system according to the inter-vehicle distance deviation and the relative speed, it is possible to obtain an accurate inter-vehicle distance in various follow-up scenes. Although it is possible to obtain the distance response, the actual value of the inter-vehicle distance is different from the target value due to the change of the running resistance according to the change of the road gradient such as when going uphill from a flat road. However, there is an unsolved problem that when the vehicle is disengaged, a large change in vehicle speed may occur due to the acceleration / deceleration control corresponding to this, and the driver may feel uncomfortable.

Therefore, the present invention has been made by paying attention to the unsolved problem of the above-mentioned conventional example, and even if the running resistance changes due to the road gradient, the driver can appropriately follow the vehicle without feeling discomfort. It is an object of the present invention to provide a preceding vehicle tracking control device that can perform traveling control.

[0005]

In order to achieve the above object, a follow-up running control device according to a first aspect of the present invention detects an inter-vehicle distance from a preceding vehicle by an inter-vehicle distance detecting means and sets an inter-vehicle distance command value. The vehicle distance command value is set based on the preceding vehicle speed, the own vehicle speed, or the like, or the driver's favorite vehicle distance command value is set, and the running resistance detecting means detects the running resistance according to the road gradient. Then, in the inter-vehicle distance command value correcting means according to the detected traveling resistance, when the traveling resistance is larger than the value corresponding to the flat road, the inter-vehicle distance command value is larger than the inter-vehicle distance command value on the flat road. It is configured to correct the value.

According to a second aspect of the present invention, in the follow-up traveling control device according to the first aspect of the invention, the inter-vehicle distance command value correcting means increases the traveling resistance with respect to a value corresponding to a flat road, and the inter-vehicle distance command value increases. Is configured to be corrected to be a larger value compared to the inter-vehicle distance command value on a flat road. Further, in the follow-up traveling control device according to claim 3, in the invention according to claim 1 or 2, the inter-vehicle distance command value correcting means decreases the inter-vehicle distance command value by a smaller value as the inter-vehicle distance command value increases. Is configured to.

[0007]

According to the first aspect of the present invention, when the running resistance increases from a flat road to an uphill road, for example, the actual inter-vehicle distance increases as compared with the flat road, but the inter-vehicle distance command value also travels. By increasing the inter-vehicle distance command value on a flat road according to the resistance, the deviation between the target inter-vehicle distance and the actual inter-vehicle distance is suppressed to a small value, and conversely, when traveling from an uphill road to a flat road, the running resistance Becomes smaller and the vehicle speed increases and the actual vehicle-to-vehicle distance decreases, but the vehicle-to-vehicle distance command value also approaches the vehicle-to-vehicle distance command value corresponding to a flat road as the running resistance decreases, and thus decreases similarly to the actual vehicle-to-vehicle distance. The deviation between the inter-vehicle distance command value and the actual inter-vehicle distance can be suppressed to a small value, and it is possible to reliably prevent a driver from feeling uncomfortable by suppressing a change in vehicle speed due to a change in traveling resistance such as when traveling on an uphill road. The effect of being able to It is obtained.

Further, according to the second aspect of the invention, the inter-vehicle distance command value is corrected so as to have a larger value as compared with the flat road, as the running resistance becomes larger with respect to the value corresponding to the flat road. According to the magnitude of the running resistance, it is possible to correct the inter-vehicle distance command value to an appropriate value, and it is possible to reliably suppress the change in vehicle speed. Further, claim 3
According to the invention, the larger the inter-vehicle distance command value, the smaller the correction amount of the inter-vehicle distance command value, so that the inter-vehicle distance is prevented from becoming too wide, and the appropriate inter-vehicle distance command value is always corrected. The effect that the amount can be obtained is obtained.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. The inter-vehicle distance sensor 1 is a radar type detector that emits a laser beam and receives the reflected light from the preceding vehicle, and detects the inter-vehicle distance L to the preceding vehicle and the relative speed ΔV between the preceding vehicle.

Here, the relative speed ΔV is the inter-vehicle distance detection value L
Or the inter-vehicle distance detection value L is obtained by hand-pass filtering. The inter-vehicle distance sensor 1 is not limited to the case of using laser light, but the inter-vehicle distance may be detected using radio waves or ultrasonic waves to calculate the relative speed. The vehicle speed sensor 2 detects the output shaft rotation speed of the transmission and converts it into the own vehicle speed V.

The preceding vehicle follow-up controller 3 is composed of a microcomputer and its peripheral portion, and sets a vehicle speed command value V ^* for following the preceding vehicle based on the input inter-vehicle distance L, relative speed ΔV, vehicle speed V, and the like. Calculate The details of the preceding vehicle tracking control controller 3 will be described later.
The vehicle speed control unit 4 calculates a throttle valve opening command value, a brake fluid pressure command value, and a gear ratio command value for matching the vehicle speed V with the vehicle speed command value V ^* , and the throttle actuator 5, the automatic brake actuator 6 and Control the transmission actuator 7. The vehicle speed control unit 4 is provided with a feedback control method and Japanese Patent Laid-Open No. 10-272.
Various control methods such as the robust model matching method shown in No. 963 can be applied.

The throttle actuator 5 adjusts the throttle valve of the engine according to the throttle valve opening command value. The automatic brake actuator 6 adjusts the brake fluid pressure according to the brake fluid pressure command value. The transmission actuator 7 adjusts the gear ratio of the transmission according to the gear ratio command value. The transmission may be a stepped transmission or a continuously variable transmission.

In this embodiment, the transfer characteristic Gv (s) of the vehicle speed control system in which the vehicle speed command value V ^* from the preceding vehicle following control controller 3 is input and the own vehicle speed V detected by the vehicle speed sensor 2 is output, , Is approximated to a first-order lag system as shown in the following equation. In _{Gv (s) = ω V /} (s + ω V) ............ (1) This equation (1), the omega _V a corner angular frequency of the vehicle speed control unit transfer characteristics.

As shown in FIG. 1, the preceding vehicle follow-up control controller 3 has a basic inter-vehicle distance command value calculation unit 31, a target inter-vehicle distance calculation constant determination unit 32, and a target inter-vehicle distance calculation, which are configured by a software form of a microcomputer. Part 3
3, vehicle speed command value calculation unit 34, front-end compensation vehicle speed command value calculation unit 35, corrected vehicle speed command value calculation unit 36, inter-vehicle distance command value correction unit 37, and road slope estimation unit 3 as running resistance detection means
Eight.

Here, in order to simplify the description, the front-end compensation vehicle speed command value calculation unit 35, the corrected vehicle speed command value calculation unit 36,
First, the basic configuration excluding the inter-vehicle distance command value correction unit 37 and the road surface gradient estimation unit 38 will be described. To the preceding vehicle following control controller 3, the inter-vehicle distance L and the relative speed ΔV are input from the inter-vehicle distance sensor 1, and the own vehicle speed V is input from the vehicle speed sensor 2. When the preceding vehicle cannot be detected by the inter-vehicle distance sensor 1, the vehicle speed set by the occupant as the target vehicle speed is output to the vehicle speed control unit 4 as the vehicle speed command value V ^* .

The preceding vehicle is detected by the inter-vehicle distance sensor 1.
In this case, the inter-vehicle distance command value calculation unit 31 compares the vehicle speed V with the own vehicle speed V.
Inter-vehicle distance command according to (2) below based on speed ΔV
Value L ^*Is calculated. L^*= A ・ Vt + L_OF      ………… (2) Where a is a coefficient, L_OFIs the offset value when the vehicle is stopped
is there. Further, Vt is the vehicle speed of the preceding vehicle, and is relative to the own vehicle speed V.
It is calculated by a value V + ΔV obtained by adding the speed ΔV.

The target inter-vehicle distance calculation constant determining unit 32 receives the inter-vehicle distance command value L ^* from the inter-vehicle distance command value calculating unit 31 as an input, and outputs the actual inter-vehicle distance L detected by the inter-vehicle distance sensor 1. in distance control system, inter-vehicle distance deviation actual headway distance L is the response characteristic of the inter-vehicle distance control to reach the inter-vehicle distance command value L ^*, is calculated by subtracting the inter-vehicle distance command value L ^* from actual inter-vehicle distance L In order to obtain an optimum response characteristic (hereinafter referred to as target inter-vehicle distance control response characteristic) according to ΔL (= L−L ^* ) and relative speed ΔV, the damping coefficient ζ _T and the natural frequency of the inter-vehicle distance control system are set. ω _T is the inter-vehicle distance deviation Δ
It is determined according to L and the relative speed ΔV.

Specifically, the damping coefficient ζ _T of the inter-vehicle distance control system corresponding to the inter-vehicle distance deviation ΔL and the relative speed ΔV and the proper characteristic are obtained so that optimum response characteristics of the inter-vehicle distance control can be obtained in various following scenes. The frequency ω _T is set in advance as a map, and the damping coefficient ζ _T and the natural frequency ω _T corresponding to the vehicle-to-vehicle distance deviation ΔL and the relative speed ΔV during the follow-up control are determined as the target vehicle-to-vehicle distance calculation constants. Here, as a map of the damping coefficient ζ _T and the natural frequency ω _T , for example, Japanese Patent Laid-Open No. 2000-135
The map described in Japanese Patent No. 934 can be applied.

The target inter-vehicle distance calculation section 33 uses the inter-vehicle distance command value L using the damping coefficient ζ _T and the natural frequency ω _T for making the response characteristic of the inter-vehicle distance control system the target response characteristic.
^The target inter-vehicle distance L _T and the target relative speed ΔV _T are calculated by passing ^* through a quadratic filter represented by the following formula (3). It should be noted that the inter-vehicle distance L ₀ and the relative speed Δ immediately after the preceding vehicle is recognized.
Let V ₀ be the initial value.

[0020]

[Equation 1] That is, the target inter-vehicle distance L _T and the target relative speed ΔV _T calculated by the equation (3) are set so that the actual inter-vehicle distance L converges to the inter-vehicle distance command value L ^* through the target response characteristic. Is a final inter-vehicle distance command value that defines the temporal transition of.

When this equation (3) is expanded and Laplace transformed, it can be expressed as the following equation (4).

[0022]

[Equation 2] This equation (4) is an inter-vehicle distance command value L^*Target distance to
Distance L_TIs a transfer function of and is expressed by a quadratic equation. This practice
In the above embodiment, in the inter-vehicle distance control system, the actual inter-vehicle distance L is
Target inter-vehicle distance L expressed by equation (4)_T(Final distance finger
Feedback control is performed so that the specified value is reached. Above
As described above, the damping coefficient ζ of the inter-vehicle distance control system _TAnd natural frequency
ω_TIn addition, according to the vehicle distance deviation ΔL and the relative speed ΔV,
Since the value that can obtain the response between the standard distance control is set,
Realizes desirable inter-vehicle distance control response in following scenes
it can.

As the target inter-vehicle distance control response, in an interrupting scene or an overtaking scene, even when the inter-vehicle distance with the preceding vehicle is below the command value, abrupt deceleration is performed if the relative speed with respect to the preceding vehicle is small. Instead, it is desirable that the actual inter-vehicle distance slowly converges to the command value. Further, in an approaching scene or the like, it is desirable that the actual vehicle-to-vehicle distance slowly converges to the command value without sudden deceleration when the vehicle-to-vehicle distance is long even when the relative speed is large. In such a follow-up scene, the actual vehicle-to-vehicle distance has a quadratic response characteristic that converges after overshooting or undershooting the command value, and such a response is shown in the equations (3) and (4). It can be realized by a secondary filter.

The vehicle speed command value calculation unit 34 uses a predetermined constant f_V
And f_LTo calculate according to the following equation (5)
Vehicle speed command value V^*Is calculated.   V^*= V (t) + ΔV (t)           -[F_V{ΔV_T(t) −ΔV (t)} + f_L{L_T(t) -L (t)}]                                                         ………… (5) In this equation (5), f_VIs the target relative speed deviation (target
Relative speed ΔV_T(Difference between (t) and relative speed detection value ΔV (t))
{ΔV_Ta constant multiplied by (t) -ΔV (t)}, f_LIs the target car
Distance deviation (Target vehicle distance L_T(t) and inter-vehicle distance detection value L
(difference with (t)) {L _T(t) −L (t)} is a constant
It

The vehicle speed control unit 4 calculates a driving force command value F ^* such that the actual vehicle speed V matches the vehicle speed command value V ^* , and controls the throttle actuator 5, the automatic brake actuator 6 and the transmission actuator 7. As described above, in the feedback control system that performs feedback control so that the actual inter-vehicle distance L matches the target inter-vehicle distance L _T indicating the target inter-vehicle distance response characteristic, in order to improve the responsiveness, the control gain of the inter-vehicle distance control system is increased. There is a trade-off relationship in which the control time constant must be shortened, and then stability is sacrificed.

Therefore, a feedforward loop is added to the inter-vehicle distance feedback control system to provide an inter-vehicle distance command value L ^*.
Compensation vehicle speed command value Vc for obtaining the target inter-vehicle distance response from
Then, the vehicle speed command value V ^* obtained by the inter-vehicle distance control system is corrected by this compensation vehicle speed command value Vc. As a result, it is possible to improve responsiveness in the inter-vehicle distance control system without impairing stability.

For this reason, a front-end compensation vehicle speed command value calculation unit 35 and a corrected vehicle speed command value calculation unit 36 are added to the preceding vehicle tracking controller 3. Preliminary compensation vehicle speed command value calculation unit 3
Reference numeral 5 calculates a compensation vehicle speed command value Vc through the basic inter-vehicle distance command value L ^* through a filter represented by the following equation (6).

[0028]

[Equation 3] The filter of the equation (6) is represented by the product of the inverse system of the transfer function from the vehicle speed command value V ^* to the actual inter-vehicle distance L and the target inter-vehicle distance control response characteristic represented by the equation (4). . Here, the transfer function from the vehicle speed command value V ^* to the actual inter-vehicle distance L is the transfer function Gv of the vehicle speed control system represented by the above equation (1) in which the vehicle speed command value V ^* is input and the actual vehicle speed V is output. (s)
And the difference between the actual vehicle speed V and the preceding vehicle speed Vt, that is, the product of the relative speed ΔV and the integrator for obtaining the actual inter-vehicle distance L. The initial values when the compensation vehicle speed command value Vc is calculated by the equation (6) are the inter-vehicle distance L ₀ and the relative speed ΔV ₀ immediately after the preceding vehicle is recognized.

The corrected vehicle speed command value calculation unit 36 uses the following (7)
As shown in the formula, the vehicle speed command value V ^* calculated by the inter-vehicle distance control system
The compensated vehicle speed command value Vc is subtracted from the calculated vehicle speed command value V ^* '. V ^* '= V ^* -Vc (7) Next, the road surface slope estimating section 38 will be described. Various methods can be considered for road surface gradient estimation. In the present embodiment, as an example thereof, a method of obtaining the driving force command value F ^* from the vehicle speed control unit 4 and the actual vehicle speed V will be described.

The estimated acceleration value α _V is calculated from the actual vehicle speed V using a high pass filter as shown in the following equation (8).

[0031]

[Equation 4] In this equation (8), T _H is a filter time constant.
Next, the acceleration command value α ^* is calculated for the driving force command value F ^* by using a low-pass filter as shown in (9) below.

[0032]

[Equation 5] Then, the road surface slope estimated value Sr is calculated based on the following equation (10) from the estimated acceleration value α _V obtained by the equation (8) and the acceleration command value α ^* obtained by the equation (9).

[0033]

[Equation 6] In this equation (10), g is the gravitational acceleration. The estimation of the road gradient is not limited to the estimation based on the acceleration estimated value α _V and the acceleration command value α ^*, and the wheel speed can be set to the time as described in JP 2001-296122 A, for example. Vehicle acceleration α _V calculated by differentiation,
The difference from the acceleration detection value α _S detected by the acceleration sensor is divided by the gravitational acceleration g to approximate the gradient tan θ sin θ (=
(Α _S −α _V ) / g) may be calculated and used as the road surface gradient estimated value Sr.

The road surface gradient estimated value Sr calculated by the road surface gradient estimation unit 38 is sent to a vehicle distance command value correction unit 37 for correcting the basic vehicle distance command value L ^* output from the basic vehicle distance command value calculation unit 31. Supplied. The inter-vehicle distance command value correction unit 37 executes the command value correction process shown in FIG. 2 as a timer interrupt process every predetermined time (for example, 10 msec). In this command value correction process, first, in step S1,
It is determined whether or not the follow-up control is being performed. When the follow-up control is not being performed, the process proceeds to step S2, the inter-vehicle distance command correction value L _RE is initialized to "0", and then the process proceeds to step S9.
The inter-vehicle distance command correction value L _RE is added to the basic inter-vehicle distance command value L ^* to calculate the corrected inter-vehicle distance command value L ^* ′ (= L ^* + L _RE ), and then the timer interrupt processing is ended and a predetermined main routine is performed. Return to the program.

On the other hand, if the result of the determination in step S1 is that the follow-up control is in progress, the process proceeds to step S3, and it is determined whether or not the estimated gradient value Sr is positive, that is, the upslope. If it is an uphill gradient, the procedure proceeds to step S4. In step S4, the basic inter-vehicle distance command value L ^* is set to the predetermined value L ^* max.
It is determined whether or not the following, and if L ^* > L ^* max, the process proceeds to step S2, and if L ^* ≤L ^* max, the process proceeds to step S5.

In step S5, the basic inter-vehicle distance command is issued.
Value L^*Calculation of the inter-vehicle distance command correction value constant based on
Inter-vehicle distance command correction value constant K with reference to the map_RECalculate
It This inter-vehicle distance command correction value constant calculation map is shown in Fig. 3.
As shown in the horizontal axis, the basic inter-vehicle distance command value L^*And the vertical axis
Inter-vehicle distance command correction value K_REIt is configured by taking the
Distance command value L^*Is 0, the inter-vehicle distance command
Correction value constant K_REIs the maximum value K_REmax, and is this the state
To basic inter-vehicle distance command value L^*Is increasing this basic inter-vehicle distance
Separation command value L^*Is a predetermined value L^*car until it reaches min
Inter-distance command correction value constant K_REIs the maximum value K_REmaintain max
The basic inter-vehicle distance command value L^*Is a predetermined value L^*beyond min
The basic inter-vehicle distance command value L^*According to the increase of
Inter-vehicle distance command correction value constant K_REIs the maximum value K_REXu from max
Decrease gradually, basic inter-vehicle distance command value L ^*Is a predetermined value L^*ma
When x is reached, the inter-vehicle distance command correction value constant K_REIs "0"
Is set to.

Next, in step S6, the estimated road surface slope value Sr is multiplied by the inter-vehicle distance command correction value constant K _RE calculated in step S5 to obtain the inter-vehicle distance command correction value L _RE (= K _RE × Sr). After calculating, the process proceeds to step S7. In this step S7, it is determined whether or not the inter-vehicle distance command correction value L _RE calculated in step S6 is less than or equal to the maximum value L _RE max, and when L _RE ≦ L _RE max, the process directly proceeds to step S9, When L _RE > L _RE max, the process proceeds to step S8, where the maximum value L _RE max is set as the inter-vehicle distance command correction value L _RE , and then the process proceeds to step S9.

The command value correction processing of FIG. 2 corresponds to the target inter-vehicle distance correction means. Next, the operation of the above embodiment will be described. Assuming that the vehicle is traveling on a flat ground following the preceding vehicle, the equation (2) is calculated on the basis of the vehicle speed Vt of the preceding vehicle to obtain an appropriate inter-vehicle distance command value L ^*.
Is calculated. At this time, the actual inter-vehicle distance L between the host vehicle and the preceding vehicle detected by the inter-vehicle distance sensor 1 substantially matches the inter-vehicle distance command value L ^* as shown in FIG. Therefore, the relative vehicle speed ΔV is maintained as shown in FIG.
As shown in (b), it is substantially "0", and the vehicle speed V is as shown in FIG.
As shown in (c), it substantially matches the vehicle speed Vt of the preceding vehicle. Furthermore, the vehicle is traveling on a flat road, and the estimated acceleration value α calculated based on the vehicle speed V by the filter of the equation (8).
_{Since V} and the acceleration command value α ^* calculated based on the driving force command value F ^* output from the vehicle speed control unit 4 by the filter of the above formula (9) are substantially equal to each other, The road surface slope estimated value Sr calculated by the equation (10) is shown in FIG.
As shown in (d), it is maintained at approximately "0".

Therefore, when the command value correction processing of FIG. 2 is executed by the inter-vehicle distance command value correction unit 37, the inter-vehicle distance control is in progress, so the process proceeds from step S1 to step S3. Since Sr is "0", the process proceeds to step S2, the inter-vehicle distance command correction value L _RE is set to "0", and the corrected inter-vehicle distance command value L ^* 'is set to the inter-vehicle distance command value L.
^It is equal to ^* .

Therefore, in the target inter-vehicle distance calculating section 33,
The target inter-vehicle distance ΔL _T according to the inter-vehicle distance command value L ^* is calculated, and this is supplied to the vehicle speed command value calculation unit 34 to calculate the vehicle speed command value V ^* , and this vehicle speed command value V ^* is the corrected vehicle speed command value. By being supplied to the calculation unit 36, the corrected vehicle speed command value calculation unit 36 subtracts the compensation vehicle speed command value Vc supplied from the front-end compensation vehicle speed command value calculation unit 35 from the vehicle speed command value V ^* to obtain the corrected vehicle speed command. By calculating the value V ^* ′,
The responsiveness is improved without impairing the stability in the inter-vehicle distance control system.

Then, by supplying the corrected vehicle speed command value V ^* 'to the vehicle speed control section 4, the driving force command value F ^* is calculated by the robust model matching method in consideration of running resistance,
By controlling the throttle actuator 5 and the transmission actuator 7 on the basis of the calculated driving force command value F ^* , the vehicle speed control is performed so that the actual inter-vehicle distance L detected by the inter-vehicle distance sensor 1 matches the basic inter-vehicle distance command value L ^*. I do.

If the vehicle speed Vt of the preceding vehicle maintains a constant vehicle speed as shown by the broken line in FIG. 4 (c) when approaching an uphill at time t1 from the traveling state on the flat road, the basic vehicle distance is reduced. The inter-vehicle distance command value L ^* calculated by the distance command value calculation unit 31 is the preceding vehicle speed Vt as shown by the dotted line in FIG.
Maintains a constant value, the inter-vehicle distance command value L ^* during traveling on a flat road is maintained.

However, the own vehicle speed V is
As shown by the solid line in 4 (c), the running resistance due to the upward slope
As the vehicle speed decreases with the increase of
The relative speed ΔV of V also decreases as shown in FIG. This
When, the vehicle is approaching a constant uphill slope
Road surface gradient estimation calculated by the road surface gradient estimation unit 38
The value Sr gradually increases in the positive direction as shown in FIG.
It Therefore, in the command value correction process of FIG.
To step S4, the basic inter-vehicle distance command value calculation unit
Inter-vehicle distance command value L calculated in 31^*Is the maximum value L^*ma
Since the state is smaller than x, go to step S5.
Transition, inter-vehicle distance command value L^*Based on the distance between vehicles in Figure 3
Refer to the command correction value constant calculation map to
Positive constant K_RETo calculate. At this time, the inter-vehicle distance command value L
^*Is a predetermined value L^*If it is less than or equal to min, the correction value
Constant K_REAs the maximum value K _REmax is calculated.

[0044] Then, the calculated inter-vehicle distance command correction value L _RE the calculated correction value constant K _RE by multiplying the road surface gradient estimated value St, inter-vehicle distance and the calculated inter-vehicle distance command correction value L _RE command value L ^Since the corrected inter-vehicle distance command value L ^* ′ is calculated by adding to ^* , the calculated inter-vehicle distance command value La ^* is calculated as the inter-vehicle distance command value L shown by the dotted line in FIG. 4A. ^* Greater value.

As described above, the corrected inter-vehicle distance command value La ^* becomes a large value, so that the target inter-vehicle distance L _T and the target relative speed ΔV _T calculated by the target inter-vehicle distance calculation unit 33 increase, and in response thereto. The vehicle speed command value V ^* calculated by the vehicle speed command value calculation unit 34 based on the equation (6) is shown in FIG.
In (c), it decreases as shown by the dotted line. Then, as the vehicle speed V decreases, the actual inter-vehicle distance L with the preceding vehicle detected by the inter-vehicle distance sensor 1 is set so as to follow the corrected inter-vehicle distance command value L ^* ′ as shown by the solid line in FIG. To increase. After that, when the corrected inter-vehicle distance command value L ^* ′ starts to converge to a constant value, the vehicle speed command value V ^* starts to increase, and the actual inter-vehicle distance L becomes the preceding vehicle speed Vt that matches the corrected inter-vehicle distance command value L ^* ′. Will match.

Thereafter, when the actual inter-vehicle distance L overshoots and slightly increases from the corrected inter-vehicle distance command value L ^* ',
In order to suppress this, the vehicle speed command value V ^* is set to the preceding vehicle speed Vt.
The value becomes larger, and accordingly, the actual inter-vehicle distance L is controlled so as to match the corrected inter-vehicle distance command value L ^* ′. Thus, when approaching an uphill, the corrected inter-vehicle distance command value L ^* 'begins to decrease due to an increase in running resistance due to the vehicle speed V traveling uphill, as the uphill slope increases. The actual vehicle-to-vehicle distance L is increased according to the road surface gradient estimated value St so that the actual vehicle-to-vehicle distance L is increased according to the road surface gradient estimated value St. Only a slight increase in vehicle speed when overshooting the distance command value L ^* ′ is required, and it is possible to reliably prevent a large change in vehicle speed, and the vehicle speed change time is also short.

Then, at time t2, the actual inter-vehicle distance L is the corrected vehicle.
Distance command value L^*If it matches ′, the vehicle speed command value V^*Ahead
It will match the traveling vehicle speed Vt, and keep this state
Uphill slope is corrected to the preceding vehicle Inter-vehicle distance command value L^*Keep '
And follow. Then, at time t3, climb uphill
When the uphill gradually decreases, the uphill
As the vehicle resistance decreases due to the decrease in
V will increase. In this case also, the road surface slope estimation unit
The estimated road surface slope value Sr calculated at 38 gradually decreases.
The vehicle distance calculated by the vehicle distance command value correction unit 37 in accordance with
Distance command correction value L_REBecomes gradually smaller, and
Corrected inter-vehicle distance command value L ^*'Is the one-dot chain line in Fig. 4 (a)
It gradually decreases as shown. Therefore, the vehicle speed command
Vehicle speed command value V calculated by the calculator 34^*Are points in Fig. 4 (c)
It increases as shown by the line, and the vehicle speed controller 4 calculates
Drive force command value F issued^*Increases the vehicle speed
Actual vehicle-to-vehicle distance detected by vehicle-to-vehicle distance sensor 1 when V increases
L decreases as shown in FIG.

After that, when the corrected inter-vehicle distance command value L ^* 'approaches the inter-vehicle distance command value L ^* calculated by the basic inter-vehicle distance command value calculation unit 31, the vehicle speed command value V ^* calculated by the vehicle speed command value calculation unit 34 ^. Shows a decreasing tendency as shown by the dotted line in FIG. 4 (c), and the vehicle speed V detected by the vehicle speed sensor 2 accordingly.
4 continues to decrease as shown by the solid line in FIG.

Then, at time t4, when the own vehicle is traveling on a flat ground and the road surface slope estimation value Sr calculated by the road surface slope estimating section 38 becomes "0", the inter-vehicle distance command correction value L _RE Is set to “0”, the corrected inter-vehicle distance command value L ^* ′ becomes equal to the inter-vehicle distance command value L ^* calculated by the basic inter-vehicle distance command value calculation unit 31. afterwards,
When the actual inter-vehicle distance L detected by the inter-vehicle distance sensor 1 matches the corrected inter-vehicle distance command value L ^* ′, the vehicle speed command value V ^* coincides with the preceding vehicle speed Vt. Since the vehicle speed V is delayed and coincides with the preceding vehicle speed, the actual inter-vehicle distance L detected by the inter-vehicle distance sensor 1 is shown in FIG.
As shown in the solid line in (a), the corrected inter-vehicle distance command value L ^* becomes lower than the corrected inter-vehicle distance command value L ^* ', and accordingly, the vehicle speed command value V ^* decreases from the preceding vehicle speed Vt to recover the decrease in the actual inter-vehicle distance L. Let

As described above, when approaching a flat road from an uphill road, the corrected inter-vehicle distance command value L ^* 'is reduced according to the decrease of the uphill slope, and the running resistance is reduced due to the decrease of the uphill slope of the vehicle speed V. Starts to increase, and as a result, the actual vehicle-to-vehicle distance L decreases along with a decrease in the road surface gradient estimated value St along a trajectory, so that the speed change of the host vehicle speed V is equal to the speed increase due to the road surface gradient. The actual inter-vehicle distance L only needs to be slightly reduced when the corrected inter-vehicle distance command value L ^* ′ is overshot, and it is possible to reliably prevent a large vehicle speed change and the vehicle speed change time is short. It's done.

When the actual inter-vehicle distance L coincides with the corrected inter-vehicle distance command value L ^* ', that is, the inter-vehicle distance command value L ^* at time t5, the vehicle speed command value V ^* also coincides with the preceding vehicle speed Vt. The state is maintained, and the vehicle returns to the state in which it follows the preceding vehicle on the flat road while keeping the inter-vehicle distance command value L ^* . Incidentally, the inter-vehicle distance command value L ^* calculated by the basic inter-vehicle distance command value calculating section 31 without providing the inter-vehicle distance command value correcting section 37 ^.
When the vehicle speed command value V ^* is calculated by using as it is, as shown in FIG. 5, when an uphill slope is approached at time t11 from the state where the vehicle is traveling on a flat road, the traveling resistance increases and The vehicle speed V decreases as shown by the solid line in FIG. 5C, and the actual inter-vehicle distance L detected by the inter-vehicle distance sensor 1 increases accordingly as shown by the solid line in FIG. 5A. At this time, the inter-vehicle distance command value L ^* is calculated based on the vehicle speed Vt of the preceding vehicle, so that it maintains a constant value as shown in FIG.

Therefore, the vehicle speed command value V ^* calculated by the vehicle speed command value calculation unit 34 eliminates the deviation between the vehicle distance command value L ^* and the actual vehicle distance L as shown by the dotted line in FIG. 5 (c). Therefore, the vehicle speed Vt is increased from the preceding vehicle speed Vt, and accordingly, the driving force command value F ^* calculated by the vehicle speed control unit 4 is increased to shift to the acceleration state. Therefore, the own vehicle speed V is as shown in FIG.
As shown by the solid line in (c), the vehicle speed increases faster than the preceding vehicle speed Vt in order to eliminate the deviation between the inter-vehicle distance command value L ^* and the actual inter-vehicle distance L, which increases from the lowered state due to the increase in the running resistance on the uphill slope. And follows the vehicle speed command value V ^* .

As the vehicle speed V increases, the actual vehicle-to-vehicle distance L detected by the vehicle-to-vehicle distance sensor 1 gradually decreases as shown by the solid line in FIG. 5 (a), and accordingly the vehicle speed command value V ^*.
5 (c) is gradually reduced as shown by the dotted line, and the actual vehicle distance L matches the vehicle distance command value L ^* at time t12, so that the vehicle speed V also matches the preceding vehicle speed Vt. The vehicle is in an uphill traveling state in which the vehicle distance L ^* is kept constant and the vehicle follows the preceding vehicle.

On the other hand, when the road gradually changes from the uphill to the flat road at time t3, the running resistance decreases due to the decrease in the road surface slope, and the vehicle speed V increases. The actual inter-vehicle distance L detected by
In (a), it decreases as shown by the solid line. In response to this, the vehicle speed command value V ^* cancels the deviation between the actual vehicle-to-vehicle distance L and the vehicle-to-vehicle distance command value L ^* as shown by the dotted line in FIG.
Since the vehicle speed decreases in a direction slower than the preceding vehicle speed Vt, the driving force command value F ^* calculated by the vehicle speed control unit 4 decreases and, for example, the throttle opening is controlled in the closing direction and detected by the vehicle speed sensor 2. As shown by the solid line in FIG. 5 (c), the vehicle speed V shifts from the acceleration state due to the decrease in the upward slope to the deceleration state, and becomes a state in which it is much lower than the preceding vehicle speed Vt.

Thereafter, the actual vehicle-to-vehicle distance L approaches the vehicle-to-vehicle distance command value L ^* due to the decrease of the vehicle speed V, the vehicle speed command value V ^* is reversed to the acceleration side, and the vehicle speed V becomes the preceding vehicle speed V.
At time t15, the actual inter-vehicle distance L coincides with the inter-vehicle distance command value L ^* , the own vehicle speed V coincides with the preceding vehicle speed Vt, and the inter-vehicle distance command value L ^* is maintained to follow the flat road. It returns to the state that does.

In this way, the inter-vehicle distance command value L ^* is calculated based on the preceding vehicle speed Vt, and the vehicle speed command value calculation unit 34 calculates the vehicle speed command value V ^* based on this inter-vehicle distance command value L ^* . When the vehicle speed control unit 4 calculates the driving force command value F ^* based on the vehicle speed command value V ^* and controls the throttle actuator 5, the automatic brake actuator 6 and the transmission actuator 7 based on this,
As shown in FIG. 5C, when approaching an uphill grade from a flat road, the actual vehicle distance L is reduced by the vehicle distance V due to the decrease in the vehicle speed V due to the decrease in the vehicle speed due to the increase in running resistance ^. In order to eliminate the longer time, the own vehicle speed V is increased more than the preceding vehicle speed Vt, so that the vehicle speed change amount increases and the vehicle speed change time also increases, which gives the driver a feeling of strangeness. Similarly, when returning from an uphill slope to a flat road, the vehicle-to-vehicle distance V decreases from the actual vehicle-to-vehicle distance V due to the decrease in the vehicle-to-vehicle speed V due to the decrease in the traveling resistance, contrary to the above ^. In order to eliminate the shortening, the own vehicle speed V is greatly reduced from the preceding vehicle speed Vt, so that the vehicle speed change amount becomes large, the vehicle speed change time becomes long, and the actual inter-vehicle distance becomes too short. It gives the driver a feeling of strangeness.

On the other hand, in the present embodiment, as described above, the road surface gradient is estimated and corrected in the direction in which the inter-vehicle distance command value L ^* increases in accordance with the estimated road surface gradient. When the vehicle is approaching an uphill grade from a flat road, the vehicle speed V is surely suppressed from increasing much beyond the preceding vehicle speed Vt, and when returning to a flat road from this uphill road, the own vehicle speed V is increased. It is possible to reliably suppress a large decrease beyond the vehicle speed Vt, and it is also possible to reliably suppress a reduction in the actual inter-vehicle distance, and it is possible to reliably prevent the driver from feeling uncomfortable. .

Further, the inter-vehicle distance command correction value L^*′ Is calculated
Inter-vehicle distance command correction value constant K for _REIs the inter-vehicle distance command value
L^*Since it is calculated by referring to the map of FIG. 3 based on
Inter-vehicle distance command value L^*If K is short, a large constant K_REage
Inter-vehicle distance command value L^*The longer the value, the smaller the constant K_RETo
Since it is calculated, the corrected inter-vehicle distance command value L^*′ Becomes larger
To prevent the actual inter-vehicle distance L from expanding too much,
An appropriate correction amount can be obtained.

In the above embodiment, the case where the basic vehicle distance command value calculation unit 31 calculates the vehicle distance command value L ^* based on the preceding vehicle speed Vt has been described, but the invention is not limited to this. Alternatively, the own vehicle speed V may be applied instead of the preceding vehicle speed Vt, and the inter-vehicle distance command value L ^* may be calculated as a function of the own vehicle speed V as shown in the following equation (11).

L ^* = a ′ · V + L _OF ′ (11) where a ′ is a coefficient and L _OF ′ is an offset value when the vehicle is stopped. As the inter-vehicle distance command value L ^* , inter-vehicle distance setting means for setting the inter-vehicle distance to, for example, large, medium, or small is provided near the driver's seat, and the set value set by the inter-vehicle distance setting means according to the occupant's preference is set. It may be used.

Further, in the above embodiment, a feedforward loop is added to the inter-vehicle distance feedback control system to obtain the compensation vehicle speed command value Vc for obtaining the target inter-vehicle distance response from the inter-vehicle distance command value L ^*, and the compensation vehicle speed command is obtained. Value V
The case where the vehicle speed command value V ^* obtained by the inter-vehicle distance control system is corrected by c to improve the responsiveness without deteriorating the stability in the inter-vehicle distance control system has been described, but the present invention is not limited to this. Alternatively, the front-end compensation vehicle speed command value calculation unit 35 and the corrected vehicle speed command value calculation unit 36 may be omitted.

Further, in the above-described embodiment, the road surface slope estimating section 38 uses the acceleration estimated value α _V and the acceleration command value α.
^Although the case where the road surface gradient estimated value Sr is calculated based on ^* has been described, the present invention is not limited to this, and an inclinometer that detects a road surface gradient and outputs an electric signal corresponding to the road surface gradient is provided. May be. Furthermore, in the above embodiment, the road surface slope estimating unit 3 is used as the running resistance detecting means.
Although the case where 8 is applied has been described, the present invention is not limited to this, and it is possible to detect a state in which the running resistance becomes larger than the running resistance when traveling on a flat road and the vehicle speed decreases. Good.

Furthermore, in the above embodiment, the inter-vehicle distance command correction value constant calculation map is as shown in FIG.
The case where the inter-vehicle distance command correction value constant K _RE continuously decreases as the inter-vehicle distance command value L ^* increases from the predetermined value L ^* min has been described, but the present invention is not limited to this. The value may be decreased in a stepwise manner in accordance with an increase in the value L ^* , or the inter-vehicle distance command correction value constant K _RE may be set to a constant value. The correction value constant K _RE may be calculated by an equation corresponding to the characteristic line.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing an example of a command value correction processing procedure in an inter-vehicle distance command value correction unit 37.

FIG. 3 is a map showing a relationship between an inter-vehicle distance command value L ^* and an inter-vehicle distance command correction value constant K _RE .

FIG. 4 is a time chart for explaining the operation of the embodiment of FIG.

FIG. 5 is a time chart for explaining the operation when the inter-vehicle distance command value is not corrected by the road surface gradient.

[Explanation of symbols]

1 inter-vehicle distance sensor 2 vehicle speed sensor 3 Leading vehicle tracking controller 4 Vehicle speed control section 5 Throttle actuator 6 Automatic brake actuator 7 Transmission actuator 31 Basic inter-vehicle distance command value calculation unit 32 Target inter-vehicle distance calculation constant determination unit 33 Target distance calculation unit 34 Vehicle speed command value calculator 35 Front compensation vehicle speed command value calculation unit 36 Corrected vehicle speed command value calculation unit 37 Inter-vehicle distance command value correction unit 38 Road surface gradient estimation unit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B60R 21/00 627 B60R 21/00 627 F02D 29/02 301 F02D 29/02 301D G08G 1/16 G08G 1 / 16 E // B60T 7/12 B60T 7/12 CF F Term (reference) 3D044 AA25 AB01 AC26 AC57 AC59 AD04 AD17 AD21 AE01 AE04 AE14 AE18 AE19 AE21 AE27 3D046 BB18 BB26 GG02 GG06 HH20 HH22 H24 A06 AC05 AC23 AC06 AC57 AC59 DB05 DB16 DB18 EA09 EB03 EB04 EC01 EC04 FA02 FA07 FA08 FA10 FA11 FA12 FB01 FB02 5H180 AA01 CC03 CC14 LL09 LL14

Claims (3)

[Claims] 1. An inter-vehicle distance detecting means for detecting an inter-vehicle distance with a preceding vehicle, an inter-vehicle distance command value setting means for setting an inter-vehicle distance command value with a preceding vehicle, a traveling resistance detecting means for detecting traveling resistance, An inter-vehicle distance command value correcting means for correcting the inter-vehicle distance command value according to the traveling resistance detected by the traveling resistance detecting means, wherein the inter-vehicle distance command value correcting means detects the traveling resistance detected by the traveling resistance detecting means. Is larger than a value equivalent to a flat road, the preceding vehicle follow-up control device is configured to correct the target inter-vehicle distance to a larger value compared to a flat road. 2. The inter-vehicle distance command value correcting means sets the inter-vehicle distance command value to a larger value compared to the inter-vehicle distance command value on the flat road as the running resistance becomes larger than the value corresponding to the flat road. The preceding vehicle follow-up control device according to claim 1, characterized in that: 3. The preceding vehicle follower according to claim 1, wherein the inter-vehicle distance command value correcting means sets the correction amount of the inter-vehicle distance command value to a smaller value as the inter-vehicle distance command value increases. Control device.