JPH11291789A - Running control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent vehicle speed from being fluctuated when a preceding car goes out of sight while follow-up running control over an uphill road is being executed in a running control device for follow-up running while a distance between cars is being kept constant. SOLUTION: In follow-up running control, when a preceding car goes out of sight, and when a vehicle is running over an up-hill road in particular, it is judged that the preceding car is running over a flat road in a place close to the apex of the up-hill road, or is running a descending road, running time (t) from the present running position up to the present running position of the preceding car, is computed, and concurrently, torque deviation Ts is computed in such a way that driving torque Tp at the of running over the flat road, is subtracted from previous driving torque To (n-1), computed torque deviation is divided by the running time (t) so as to allow the variation ΔT of driving torque to be computed, and vehicle speed is thereby prevented from being fluctuated by executing torque down control reducing a target driving torque T* in response to the variable ΔT of driving torque.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular travel control device which performs speed control for following a preceding vehicle while maintaining a distance between the vehicle and the preceding vehicle.

[0002]

2. Description of the Related Art As a conventional traveling control device for a vehicle, for example, one described in Japanese Patent Application Laid-Open No. 6-255394 is known.

[0003] In this conventional example, a constant speed traveling control means for controlling the constant speed traveling of the vehicle based on outputs of a vehicle speed setting means, a vehicle speed detecting means and a throttle opening detecting means, and an output of the constant speed traveling controlling means. Automatic transmission control means for controlling the switching of the speed change means of the vehicle based on the constant speed travel control means, at least based on the output of the vehicle speed detection means and the throttle opening degree detection means of the road traveling at a constant speed A vehicle constant-speed traveling control device is described in which a gradient is estimated, and the automatic transmission control means is controlled in accordance with the estimation result, whereby the gradient of the traveling path is accurately determined and traveling control is performed. .

[0004]

However, in the above-mentioned conventional constant-speed traveling control device for a vehicle, a driving torque corresponding to the gradient is generated by controlling the automatic transmission in accordance with the gradient of the traveling road. However, when the constant-speed traveling control device for a vehicle is applied to a following traveling control device that travels while maintaining a constant inter-vehicle distance to a preceding vehicle, the preceding traveling vehicle is detected on an uphill road. However, if the vehicle is controlled so as to maintain a constant inter-vehicle distance therefrom, the optimal following control can be performed by setting a driving torque according to the gradient of the uphill road at that time. At the end of the uphill road, when the preceding vehicle travels on a flat road and the inter-vehicle distance cannot be detected, it is determined that the preceding vehicle has disappeared, and the vehicle immediately enters the acceleration control state for a certain period of time. Passage However, since the driving torque at this time is set for the uphill road, when the vehicle shifts from the uphill road to the flat road, as shown in FIG. Therefore, there is an unsolved problem that the vehicle speed temporarily increases and then converges to the target vehicle speed.

Accordingly, the present invention has been made in view of the above-mentioned unsolved problems of the prior art. In the following running state, the vehicle travels on an uphill road while maintaining a constant inter-vehicle distance with the preceding vehicle. It is an object of the present invention to provide a vehicle travel control device capable of performing a stable travel by preventing a drive torque excessive state due to a gradient change by gradually reducing the drive torque when the vehicle cannot detect the vehicle. .

[0006]

According to a first aspect of the present invention, there is provided a vehicle travel control apparatus for controlling a speed of following a preceding vehicle while maintaining a predetermined distance between the vehicle and the preceding vehicle. The inter-vehicle distance detecting means for detecting the inter-vehicle distance from the preceding vehicle, the driving torque calculating means for calculating the driving torque of the own vehicle, and the inter-vehicle distance detected by the inter-vehicle distance detecting means. Following running control means for performing following running control so that the vehicle distance coincides with the target inter-vehicle distance, and a state in which the following vehicle detecting section cannot detect a preceding vehicle when the preceding vehicle is detected by the following inter-vehicle distance detecting means during uphill running during the following running control. When it is determined that the vehicle is near the end of the uphill, the following traveling control by the following traveling control means is interrupted, and the driving torque calculated by the driving torque calculating means is calculated on a flat road. It is characterized in that a drive torque control means so as to gradually change the driving torque.

According to a second aspect of the present invention, in the vehicle traveling control apparatus according to the first aspect of the present invention, when the drive torque control means determines that the vehicle is near the end of the uphill, the immediately preceding inter-vehicle distance and vehicle speed are used. And a deviation between the immediately preceding driving torque and the driving torque on a flat road, and a change rate is calculated, and the target driving torque is reduced at the change rate. .

Further, in the vehicle travel control device according to claim 3, in the invention according to claim 1 or 2, when the torque control by the drive torque control device is completed, the preceding vehicle is detected by the inter-vehicle distance detection device. Is detected, the following cruise control by the following cruise control means is restarted, and when the preceding vehicle is not detected, the drive torque at the end of the torque control is held for a predetermined time, and then the acceleration control is permitted. Features.

According to a fourth aspect of the present invention, in the vehicle travel control device according to any one of the first to third aspects, the driving torque control means increases the torque during the torque down control for reducing the target driving torque. When a request is made, the torque-up request is prioritized.

[0010]

According to the first aspect of the present invention, when the state changes from a state in which the preceding vehicle is being detected to a state in which the preceding vehicle cannot be detected when climbing a hill, the state in which the preceding vehicle travels on a flat road or downhill from an uphill road. It is determined that the vehicle is near the end of the uphill road, and the driving torque for the uphill road is gradually returned to the driving torque for the flat road, so that the vehicle travels on the flat road or downhill from the uphill road. In this case, it is possible to reliably prevent the drive torque from becoming excessive when the vehicle is running, and to obtain the effect that the traveling control can be performed without causing a change in the vehicle speed.

According to the second aspect of the present invention, the running time required for the vehicle to reach the preceding vehicle position when the preceding vehicle cannot be detected on the uphill road is calculated. A deviation between the driving torque and the driving torque on a flat road is calculated, a rate of change of the driving torque is calculated from the calculated traveling time and the driving torque deviation, and the target driving torque is reduced at the rate of change. When the vehicle reaches the traveling position of the preceding vehicle when the preceding vehicle cannot be detected, the driving torque can be reliably returned to the driving torque on a flat road, and the excessive driving torque is more reliably prevented, The effect is obtained that the traveling control can be performed without causing a change in the vehicle speed.

Further, according to the third aspect of the present invention, when the torque control by the driving torque control means is completed, and when the preceding vehicle is detected by the inter-vehicle distance detecting means, the following control by the following traveling control means is performed. When the traveling control is restarted and the preceding vehicle is not detected, the driving control at the end of the torque control is held for a predetermined time, and then the acceleration control is permitted. In the case where is not detected, the acceleration control can be suppressed for a predetermined time, and an effect is obtained that inadvertent acceleration can be prevented and stable running can be ensured.

Further, according to the invention according to claim 4, when the torque increase request is made during the torque down control for decreasing the target drive torque, the drive torque control means gives priority to the torque increase request. With this configuration, when a torque increase request is made while a preceding vehicle cannot be detected on an uphill road, it can be determined that the gradient has become steeper, and the drive torque can be increased, thus lowering the uphill ability. There is an effect that traveling control can be performed without causing the vehicle to run.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment in which the present invention is applied to a rear-wheel drive vehicle. In the drawing, 1FL and 1FR are front wheels as driven wheels, 1RL and 1FR.
RR is a rear wheel as a driving wheel, and rear wheels 1RL, 1R
R is driven to rotate by the driving force of the engine 2 being transmitted via the automatic transmission 3, the propeller shaft 4, the final reduction gear 5, and the axle 6.

Front wheels 1FL, 1FR and rear wheels 1RL, 1R
R is provided with a disc brake 7 for generating a braking force, and the braking oil pressure of the disc brake 7 is controlled by a braking control device 8.

Here, the braking control device 8 generates a braking oil pressure in response to the depression of a brake pedal (not shown) and generates a braking oil pressure in response to a braking pressure command value from a traveling control controller 20 described later. Is configured.

The engine 2 is provided with an engine output control device 9 for controlling the output. The engine output control device 9 controls the engine output by controlling the engine speed by adjusting the opening of the throttle valve and adjusting the opening of the idle control valve to control the engine speed by controlling the engine speed. Although a control method is conceivable, in the present embodiment, a method of adjusting the opening of the throttle valve is employed. Further, the engine output control device 9 detects the engine rotation speed _NE, and outputs this to a travel control controller 20 described later.

Further, the automatic transmission 3 is provided with a transmission control device 10 for controlling the shift position. When an up / down shift command value TS is input from a travel control controller 20 described later, the transmission control device 10 performs up shift or down shift control of the shift position of the automatic transmission 3 in response to the input. Is configured.

On the other hand, an inter-vehicle distance sensor 12 comprising a radar device as inter-vehicle distance detecting means for detecting an inter-vehicle distance from a preceding vehicle is provided below the vehicle body on the front side of the vehicle.

Further, the vehicle is provided with wheel speed sensors 13L, 13R for detecting the wheel speeds of the front wheels 1FL, 1FR. Then, it is input to the inter-vehicle distance sensor 12 and wheel speed sensors 13L, 13R engine rotational speed N _E is traveling control controller 20 from the output signal and the engine output control device 9, by the traveling control controller 20, the inter-vehicle distance inter-vehicle distance L detected by the sensor 12, wheel speed sensors 13L, a wheel speed Vw L detected by _13R, based on Vw _R, brake controller 8, by controlling the engine output controller 9 and the transmission controller 10 In addition, while performing the following traveling control while maintaining an appropriate inter-vehicle distance with the preceding vehicle, and performing the following traveling control, when the preceding vehicle can no longer be detected during the following traveling control, the vehicle is located near the top of the ascending road and the climbing is performed. Judging that the road is going to be a flat road or a downhill, the driving torque for the uphill is gradually reduced and the driving for the flat road is started. Performs torque control to return to the torque.

Next, the operation of the first embodiment will be described with the traveling control processing shown in FIG. This traveling control process is performed for a predetermined time (for example, 10 msec) for a predetermined main program.
This is executed as a timer interrupt process for each
1 by the wheel speed sensor 13L, a wheel speed Vw L detected by _13R, reads Vw _R, by determining the average value thereof, calculates the vehicle speed V (n).

Next, the routine proceeds to step S2, where it is determined whether or not the following running control state flag FC indicating whether or not the following running control state is set is "1", and this is reset to "0". If so, it is determined that the follow-up traveling control has not been executed, and the process proceeds to step S3.

In step S3, the preceding vehicle is recognized.
Is determined. This determination is based on the following distance sensor
12 inter-vehicle distance detection values D (n) are read and set in advance.
Detection limit value D_MAXJudge whether or not
D (n)> D _MAXWhen is the preceding car
It is determined that both have not been detected, and the process proceeds to step S5.
The vehicle speed V (n) is set to a preset vehicle speed V_SET
After moving to the constant speed cruise control process
Terminates the timer interrupt processing and returns to the specified main program.
D (n) ≤ D_MAXAnd the preceding vehicle is detected
Sometimes, the process proceeds to step S6, and the following traveling control process is performed.
After executing the timer interrupt processing,
Return to program.

On the other hand, if the result of the determination in step S2 is that the control state flag FC is set to "1", it is determined that the follow-up traveling control is being executed, and the flow proceeds to step S6.
Move to

[0025] In step S6, along with reading free the engine rotational speed N _E, reads the throttle opening command value theta, Based on these, the engine with reference to the engine torque calculation map shown in FIG 4 stored in advance to calculate the torque T _E.

Then, the process proceeds to step S7 to read the transmission gear position of the automatic transmission 3 and refer to a preset gear ratio table based on the transmission gear position to check the transmission gear corresponding to the transmission gear position. Calculate the ratio C _G.

Next, the process proceeds to step S8, where the engine
Torque T_EAnd transmission gear ratio C_GBased on the following formula (1)
To calculate the drive torque at the output side of the automatic transmission 3.
K T _OIs calculated.

T _O = T _E · C _G (1) Then, the process proceeds to step S9, and the above-described step S9 is performed.
It is determined whether or not the preceding vehicle is recognized in the same manner as in step 3, and if the preceding vehicle is recognized, the process proceeds to step S10, where the torque-down control state flag FT is reset to "0", and then the process proceeds to step S5. The process proceeds to step S11 when the preceding vehicle is not recognized.

In step S11, it is determined whether or not a torque-down control state flag FT indicating whether or not a torque-down control state is set is set to "1", and if it is reset to "0". Step S12
Then, it is determined whether or not the vehicle is traveling on an uphill road. The determination in this case is made by determining whether or not the ratio of the driving torque T _O to the own vehicle speed V (n) is large based on the driving torque T _O and the own vehicle speed V (n) calculated in step S8. It is determined whether or not the vehicle is traveling on an uphill road. If the vehicle is not traveling on an uphill road, the flow proceeds to step S12a to reset the follow-up traveling control flag FC to "0", and then proceeds to step S4, where the vehicle is traveling on an uphill road. If, the process proceeds to step S13.

In this step S13, the preceding vehicle can be detected by calculating the following equation (2) based on the preceding inter-vehicle distance detection value D (n-1) and the current vehicle speed detection value V (n). The running time t to the running position of the preceding vehicle at the time of the running is calculated.

T = D (n-1) / V (2) Then, the process proceeds to step S14, and from the previous driving torque T _O (n-1) as shown in the following equation (3). by subtracting the required driving torque T _P in a flat road both torque deviation T _S
Is calculated.

T _S = T _O (n−1) −T _P (3) Then, the process proceeds to step S 15, where the torque deviation T _S calculated as shown in the following equation (4) is calculated as the running time. The change amount ΔT of the driving torque is calculated by dividing by t.

ΔT = T _s / t (4) Next, the routine proceeds to step S16, where a torque-down control state flag FT indicating whether or not torque-down control is being performed.
Is set to “1”, the count value T _M of the elapsed time timer described later is cleared to “0”, and
17, the value obtained by subtracting the variation ΔT from the previous drive torque T _O (n−1) is set as the target torque T ^* , and then the process proceeds to step S18 to open the target throttle opening for generating the target torque T ^*. After setting the degree command value θ ^* and the transmission gear position TS of the automatic transmission 3 and outputting them to the engine output control device 9 and the transmission control device 10, respectively, the timer interrupt processing is performed. It ends and returns to the predetermined main program.

On the other hand, when the result of the determination in step S11 is that the torque-down control state flag FT is set to "1", it is determined that the torque-down control state is in effect, and the flow shifts to step S19 to measure the elapsed time. After the count value T _M of the elapsed time timer is incremented by “1”, the process proceeds to step S20.

[0035] In the step S20, it determines whether the elapsed time timer elapsed time multiplied by the timer interrupt period t ₀ to the count value T _M of the became calculated travel time t or more in step S13, T _M · If t ₀ <t, it is determined that the traveling time t has not elapsed, and the process proceeds to step S2.
Proceeds to 1, and proceeds from the value obtained by subtracting the amount of change ΔT from the target driving torque T ^* as a new target driving torque T ^* in the step S18, the travel time when a T _M · t ₀ ≧ t After the elapse of t, it is determined that the torque-down control is to be ended, and the process proceeds to step S22, where both the torque-down control state flag FT and the following running control flag FC are reset to “0”, and then the process proceeds to step S3. .

As shown in FIG. 3, a specific example of the follow-up running control process in step S5 reads the inter-vehicle distance D (n) between the vehicle and the actual preceding vehicle detected by the inter-vehicle distance sensor 12 in step S61. Then, the process proceeds to step S62.
The host vehicle speed V (n) calculated in step S1 is read, and then the process proceeds to step S63 until the host vehicle speed V (n) and the host vehicle reach the current position L ₀ [m] behind the preceding vehicle. The target inter-vehicle distance D ^* (n) between the preceding vehicle and the host vehicle is calculated from the time T ₀ (inter-vehicle time) according to the following equation (5).

D ^* (n) = V (n) × T ₀ + D ₀ (5) By adopting this concept of inter-vehicle time, the inter-vehicle distance is set to increase as the vehicle speed increases. . Incidentally, D ₀ is stopped when the inter-vehicle distance.

Next, the process proceeds to step S64 to determine whether or not the inter-vehicle distance D (n) is equal to or less than the target inter-vehicle distance D ^* (n). If D (n)> D ^* (n), then Inter-vehicle distance D
(n) is greater than the target inter-vehicle distance D ^* (n), and it is determined that the inter-vehicle distance can be reduced as an acceleration state. Then, the process proceeds to step S65, based on the preset target vehicle speed V ^* . Then, the target acceleration / deceleration G ^* is calculated according to the following equation (6),
This is updated and stored in the acceleration / deceleration storage area of the memory, and the process proceeds to step S67.

[0039] _{^{G * = K A × (V}} * -V (n)) + L A ............ (6) where, K _A and L _A are constants. On the other hand, step S
When the determination result of 64 is D (n) ≦ D ^* (n), it is determined that the inter-vehicle distance D (n) is shorter than the target inter-vehicle distance D ^* (n) and it is necessary to increase the inter-vehicle distance as a deceleration state. Then, the process proceeds to step S66, calculates the target acceleration / deceleration G ^* based on the following equation (7), updates and stores this in the acceleration / deceleration storage area of the memory, and then proceeds to step S67.

[0040] _{^{G * = K B × (D}} (n) -D * (n)) -L B ............ (7) where, K _B and L _B are constants. In step S67, a target throttle opening command value θ for the engine control device 9 and an up / down shift command value TS for the transmission control device 10 are calculated, and a driving force control process for outputting these is executed. Transition.

Here, the throttle opening command value θ is equal to the target acceleration / deceleration G in the acceleration state where the target acceleration / deceleration G ^* is positive.
^* To calculate the throttle opening degree change amount Δθ to increases in the positive direction with an increase in the target deceleration is until to reach a predetermined value -G _S from "0" when the target deceleration G ^* is negative The throttle opening change amount Δθ that increases in the negative direction in accordance with the increase of G ^{* in} the negative direction is calculated, and the calculated throttle opening change amount Δθ is added to the current throttle opening command value θ to obtain a new throttle opening command value θ. such calculates the throttle opening command value theta, the target deceleration G ^* is set to "0" or a value in the vicinity of the throttle opening command value theta when exceeding the predetermined value -G _S.

The up / down shift command value TS
Is an up / down shift command value of the automatic transmission 3 based on the calculated throttle opening command value θ and the vehicle speed V (n) with reference to a shift control map similar to the shift control in a normal automatic transmission. Calculate TS.

In step S68, a target braking pressure P _B ^* is calculated based on the target acceleration / deceleration G ^* stored in the acceleration / deceleration storage area, and this is output to the braking control device 8 as a braking pressure command value. Step S after performing the control processing
The routine proceeds to 69, where the follow-up traveling control flag FC indicating whether or not the follow-up traveling control is being performed is set to "1", and then the follow-up traveling control process is terminated, and the process returns to the predetermined main program.

[0044] Here, the target braking pressure P _B ^* is the target deceleration G ^* with reference to the braking pressure calculation map shown in FIG. 5 which has previously been stored in the memory on the basis to calculate the target braking pressure P _B ^* .
As shown in FIG. 5, the braking pressure calculation map takes the target acceleration / deceleration G ^* on the horizontal axis and the target braking pressure P _B ^* on the vertical axis, and when the target acceleration / deceleration G ^* is positive and negative. Predetermined value -G
Maintaining the target braking pressure P _B ^* "0" is until exceeds _S, the target acceleration G ^* exceeds a predetermined value or more -G _S, proportional to the increase in the negative direction of the target acceleration G ^* Thus, the target braking pressure P _B ^* is set to increase linearly.

In the processing shown in FIG.
The processing of S11 corresponds to the following travel control means,
The processing of 12 to S18 corresponds to the torque down control means.

[0046] Thus, now, as shown in FIG. 6, it is assumed that the travels following at time t ₀ to the preceding vehicle on an uphill grade, as shown in Figure 6 (b). In this state, when the cruise control process of FIG. 2 is executed, the cruise control flag is set to “1” in step S69 of the cruise control process of FIG. 3 because the cruise control is continued. Are performed, steps S2 to S6 to
The process proceeds to S8, in which the drive torque T _O (n) at that time is calculated, and the previous drive torque T ₀ (n−1) updated and stored in the current drive torque storage area of the storage device is stored in the previous drive torque storage. The updated driving torque T
_O (n) is updated and stored in the current drive torque storage area of the storage device.

In this state, since the preceding vehicle has been recognized, the flow proceeds from step S9 to step S10 to step S10.
Then, the control goes to 6 to perform the following travel control so that the inter-vehicle distance D (n) matches the target inter-vehicle distance D ^* (n) corresponding to the vehicle speed.

In the state where the following running control on the uphill road is continued, at time t ₁ , the preceding vehicle runs up the uphill road and runs on a flat road. When the preceding vehicle cannot be detected, the process proceeds from step S9 to step S11 in FIG. 2, and since the torque-down control flag FT is set to "0", the process proceeds to step S12, and the vehicle is traveling on an uphill road. Then, the process proceeds to step S13, where the previous inter-vehicle distance D (n−
By dividing 1) by the current vehicle speed V (n), the travel time t until the host vehicle reaches the preceding vehicle traveling position from the current traveling position to immediately before the preceding vehicle cannot be detected is calculated.

[0049] Then, to calculate the torque deviation T _S of the drive torque T _P during running on a flat road from the previous driving torque T _O (n-1) (step S14), and then with running time t of the torque deviation T _S To calculate the torque change amount ΔT (step S
15), then set to "1" to the torque-down control state flag FT (the step S16), and then the timer interrupt period t ₀ to the variation ΔT per unit time from the previous driving torque T _O (n-1) Multiplied torque change amount ΔT · t ₀
Is set as the target driving torque T ^* , and the driving torque is controlled based on the target driving torque T ^* .

By this drive torque reduction control, the own vehicle speed V (n) when climbing a hill is slightly reduced as shown by the solid line in FIG. 6 (a). It does not cause a sudden change in vehicle speed as in the conventional example shown by the chain line in FIG.

Then, after the timer interrupt period elapses,
When the traveling control process of FIG. 3 is executed, the following traveling control
FC remains set to "1", but the torque
Control flag FT is set to "1".
Then, the process proceeds from step S11 to step S19,
Count value T of overtime timer_MIs incremented by “1”
The count value T_MTo the interrupt cycle t₀Multiply by
Elapsed time T_M・ T ₀Has not reached the running time t
Then, the process proceeds to step S21 via step S20, and
Target drive torque T^*Is the torque change amount ΔT · t₀Subtract by minutes
The calculated value is used as the new target drive torque T.^*Set to
A driving force control process is executed based on the elapsed time T.
_M・ T₀Is repeated until the running time t is reached.

Therefore, the target drive torque T ^* gradually decreases as time passes, as shown in FIG. afterwards,
When the vehicle at the time t ₂ in FIG. 6 is a state of traveling on a flat road banged up the uphill road, the target driving torque T ^* at this time it is greater than the driving torque T _P of a flat road, 6
As shown in (a), the vehicle speed V (n) tends to recover,
Thereafter, when the elapsed time T _M · t ₀ reaches the running time t at time t ₃ without recognizing the preceding vehicle, the target driving torque T
^* Becomes equal to the driving torque T _P of a flat road, step S22 from step S20 when the processing of FIG. 2 is executed
And sets the torque down control state flag FT to “0”.
And resets the follow-up running control flag FC to "0", and then proceeds to step S3.

For this reason, when the preceding vehicle is not recognized, the process proceeds to step S4 to execute a constant speed traveling control process, and performs a constant speed traveling control to match the set vehicle speed V _SET .
When the preceding vehicle is recognized, the flow shifts to step S5 to restart the following running control shown in FIG.

Then, when a predetermined timer period has elapsed and the processing of FIG. 2 is executed next, when the constant-speed running control is being performed, the process proceeds from step S2 to step S4 via step S3, and the following running control is performed. When the vehicle is in the middle, the follow-up traveling control state flag FC is set to "1".
From Step S2 to Step S6 through Steps S6 to S8
9, the process proceeds to step S5 via step S10 when the preceding vehicle is recognized, and the following traveling control state is continued.

On the other hand, even when the preceding vehicle is recognized during the above-described torque-down control, the process shifts from step S9 to step S10 in the processing of FIG. 2 to reset the torque-down control state flag FT to "0". To step S
5 and immediately resumes the follow-up running control process.

As described above, according to the first embodiment, when traveling on an uphill while following the preceding vehicle, the preceding vehicle travels up the uphill and travels on a flat road or downhill. By being in the state, the inter-vehicle distance sensor 1
When it becomes impossible to detect the preceding vehicle in 2,
When traveling to the traveling position of the preceding vehicle at that time, the large driving torque for ascending is gradually reduced, and when the own vehicle reaches the traveling position of the preceding vehicle, torque reduction control is performed so as to match the driving torque of the flat road. Therefore, the driving torque does not become excessive when the own vehicle has climbed the uphill road, the vehicle speed can be reliably prevented from greatly fluctuating, and the driver is prevented from feeling uncomfortable. Can be.

Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, in the cruise control process in the first embodiment described above, the constant speed cruise control process is not performed immediately when the preceding vehicle cannot be detected when the torque-down control is completed. The process is shifted to the constant speed traveling control process after waiting for a time.

In the second embodiment, as shown in FIG. 8, it is determined whether or not the holding state flag FH indicating the holding state is set to "1" between the processing of the steps S3 and S4. Step S31, and when the determination result is that the holding state flag FH is reset to "0", the torque down control state flag FT (n-1) in the previous process is performed.
Step S32 for determining whether or not is set to "1" is added. Then, step S32
Is determined by the previous torque-down control state flag FT.
If (n-1) is set to "1", the flow shifts to step S33 to set the holding state flag FH to "1" and to set the count value T of the holding time timer for measuring the holding time. _After clearing _H to "0", the timer interrupt processing is terminated, and if the result of the determination in step 31 is that the hold state flag FH is set to "1", the flow shifts to step S34 to hold transition from incrementing the count value T _H by "1" in time timer to step S35, it determines whether or not a set value T _HS or more corresponding to the count value T _H predetermined holding time set in advance and, as it ends the timer interrupt process when a T _H <T _HS, the process proceeds to step S36 when it is T _H ≧ T _HS, the is reset to "0" holding state flag FH stearate The same processing as in FIG. 2 is executed except that the processing is shifted to step S4, and the same processing as in FIG. 2 is denoted by the same step number, and detailed description thereof is omitted. I do.

According to the second embodiment, when it becomes impossible to detect the preceding vehicle during the follow-up control when climbing a hill, the torque down control process for reducing the drive torque at that time is performed in steps S11 to S21. Do,
When the process proceeds to step S22 and the torque-down control process ends, when the preceding vehicle is detected, the process proceeds from step S3 to step S5, and the following cruise control is immediately restarted. When the preceding vehicle is not detected, The process moves to step S31, and the holding state flag FH is still “1”.
Is not set in step S32, the process proceeds to step S32.
Since the previous torque-down control state flag FT (n-1) has been set to "1", the process proceeds to step S33, where the holding state flag FH is set to "1" and the count value of the holding time timer is set. Since _TH is cleared to "0" and the timer interrupt processing ends, the constant-speed cruise control processing is not immediately executed. When the next timer interrupt processing is executed, steps S2 to S3 are executed. , the process proceeds to step S34 through step S31, is incremented count value T _H of the retention time timer, by repeating this state, determines that the retention time count value T _H is the set value T _HS more has elapsed Then, in step S36, the holding state flag FH is reset to "0", and then the flow shifts to step S4 to execute the constant speed traveling control processing.

For this reason, if the preceding vehicle cannot be recognized at the time of reaching the lost preceding vehicle position after the vehicle has climbed the uphill road, it is highly likely that the vehicle is on a downhill. After the predetermined holding time elapses, the vehicle shifts to the constant speed traveling control and permits the vehicle to accelerate, so that when the vehicle travels downhill following the uphill road, unnecessary acceleration is performed. A stable running can be ensured without any occurrence of a state.

Next, a third embodiment of the present invention will be described with reference to FIG. In the third embodiment, when there is a request to increase the torque during the torque-down control, it is determined that the gradient becomes steeper, and the torque-down control process is stopped to give priority to the torque-up process. It was made.

In the third embodiment, FIG.
As described above, in the traveling control process of FIG.
The current drive torque T is set between step S9 and step S11.
_O(n) to the previous drive torque T_OTorr minus (n-1)
Change amount δT (= T_O(n) −T_O(n-1))
Set value δT_SStep S to determine whether or not it is above
41, and the determination result in this step S41 is δ
T <δT_SJudge that the gradient change is small when
Then, the process proceeds to step S11, where δT ≧ δT _SIs
Sometimes, it is determined that the angle has changed to a steep gradient, and step S4
2 and the target torque T^*Drive torque T
_O(n) is set, and then the torque is reduced in step S43.
Both the control state flag FT and the following control state flag FC
After resetting to "0", the process proceeds to the step S18.
The same processing as in FIG. 2 is performed except that
The same step numbers are assigned to the processes that
This is omitted.

According to the third embodiment, the vehicle is tracked on an uphill road.
When the preceding vehicle cannot be detected during following driving
Judge that your vehicle is traveling near the top of the uphill road.
The torque down control in steps S11 to S22
Move to the process, but in this running state,
Suddenly, the current drive torque T_O(n) before
Drive torque T_OLarge value for (n-1)
Then, the process proceeds from step S41 to step S42,
Current drive torque T_O(n) is the target drive torque T ^*As
By setting, giving priority to torque-up control,
A decrease in vehicle speed can be prevented. Each of the above implementations
In the embodiment, in the following travel control process,
Vehicle speed feedback type and (7) type inter-vehicle distance feed
The case where the back formula is set to P control has been described.
However, it is not limited to
Needless to say, it may be used.

[0064] In the above embodiments, by calculating a target inter-vehicle distance D ^* in the follow-up run control process compares the actual inter-vehicle distance D between the target inter-vehicle distance D ^*,
Although the case where the target acceleration / deceleration G ^* is calculated has been described,
The present invention is not limited to this, and the target vehicle speed is set so that the time (inter-vehicle time) T ₀ until the host vehicle reaches behind the preceding vehicle L ₀ (m) based on the inter-vehicle distance D (n) is constant. V
^* (n) is determined, and the deviation ΔV between this and the actual vehicle speed V (n) is determined.
(n), the engine output command value α is calculated. If the value is positive, the engine is controlled to an acceleration state based on the calculated engine output command value α, and if the value is negative, the speed deviation ΔV (n) May be set by PD control or PID control on the basis of the target braking pressure.

Further, in each of the above embodiments, the case where the own vehicle speed V (n) is calculated by the average value of the wheel speeds of the driven wheels has been described. However, the present invention is not limited to this. It is also possible to calculate the vehicle speed by detecting the number of revolutions on the output side, or to apply a vehicle speed calculating means used in the antilock brake control device.

Furthermore, in each of the above embodiments,
Although the case where the automatic transmission 3 is provided on the output side of the engine 2 has been described, the invention is not limited to this, and a continuously variable transmission may be applied.

In the above embodiment, the case where the present invention is applied to a rear wheel drive vehicle has been described. However, the present invention can be applied to a front wheel drive vehicle or a four wheel drive vehicle. Instead, the present invention can be applied to an electric vehicle to which an electric motor is applied, or a hybrid vehicle using both the engine 2 and the electric motor. In this case, an electric motor control device may be applied instead of the engine output control device.

[Brief description of the drawings]

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

FIG. 2 is a flowchart illustrating an example of a travel control processing procedure of a travel control controller.

FIG. 3 is a flowchart illustrating a specific example of a follow-up traveling control process in the traveling control process of FIG. 2;

FIG. 4 is a control map showing a relationship between an engine rotation speed and an engine torque using a throttle opening as a parameter.

FIG. 5 is an explanatory diagram showing an example of a target braking pressure calculation map showing a relationship between a target acceleration / deceleration and a target braking pressure.

FIG. 6 is a time chart for explaining the operation of the first embodiment;

FIG. 7 is a time chart illustrating a decrease change characteristic of a target torque during torque down control.

FIG. 8 is a flowchart showing a traveling control process applicable to the second embodiment of the present invention.

FIG. 9 is a flowchart showing a traveling control process applicable to the third embodiment of the present invention.

FIG. 10 is a time chart for explaining the operation of the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1FL, 1FR Front wheel 1RL, 1RR Rear wheel 2 Engine 3 Automatic transmission 7 Disc brake device 8 Brake control device 9 Engine output control device 10 Transmission control device 12 Distance between vehicles 13L, 13R Wheel speed sensor 20 Controller for traveling control

Claims (4)

[Claims] An inter-vehicle distance detecting means for detecting an inter-vehicle distance from a preceding vehicle, wherein the inter-vehicle traveling control device performs speed control for following the preceding vehicle while maintaining the inter-vehicle distance to the preceding vehicle at a predetermined value. A drive torque calculating means for calculating a drive torque of the own vehicle; a follow-up travel control means for performing a follow-up travel control so that the inter-vehicle distance detected by the inter-vehicle distance detection means coincides with a target inter-vehicle distance; In the following cruise control, when the vehicle is detected from the state in which the preceding vehicle is detected by the inter-vehicle distance detecting means at the time of climbing a hill, it is determined that the vehicle is near the end of hill climbing and the following cruise control by the following cruise control means is performed. And a drive torque control means for interrupting and gradually changing the drive torque calculated by the drive torque calculation means to a drive torque on a flat road. Traveling control device for vehicles. When the drive torque control means determines that the vehicle is near the end of the uphill, the drive torque control means calculates a difference between the immediately preceding drive torque and the immediately preceding drive torque and the drive torque on a flat road. The vehicle travel control device according to claim 1, wherein a change rate is calculated from the deviation, and the target drive torque is reduced at the change rate. 3. When the preceding vehicle is detected by the inter-vehicle distance detecting means when the torque control by the driving torque control means ends, the following driving control by the following driving control means is restarted, and 2. The control system according to claim 1, wherein when the detection is not performed, the acceleration control is permitted after the driving torque at the time of the end of the torque control is held for a predetermined time.
Or the running control device for a vehicle according to 2. 4. The system according to claim 1, wherein the drive torque control means is configured to give priority to the torque-up request when a torque-up request is made during the torque-down control for reducing the target drive torque. Item 4. The vehicle travel control device according to any one of Items 1 to 3.