JP4114539B2 - Inter-vehicle distance control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inter-vehicle distance control device that controls an inter-vehicle distance from a preceding vehicle by controlling a traveling state of the host vehicle.
[0002]
[Prior art]
When there is no preceding vehicle, the vehicle travels according to the traveling speed set by the occupant. When there is a preceding vehicle, the inter-vehicle distance from the preceding vehicle is detected, and the inter-vehicle distance and the host vehicle are lower than the speed set by the occupant. An inter-vehicle distance control device has been proposed in which traveling control is performed in accordance with the relative speed between the vehicle and the preceding vehicle. In such an inter-vehicle distance control device, when a preceding vehicle traveling at a speed higher than that of the own vehicle is newly detected at an inter-vehicle distance shorter than the target inter-vehicle distance, for example, by interruption or overtaking, the current own vehicle By setting the vehicle speed to the target speed, the inter-vehicle distance is gradually increased to make the inter-vehicle distance coincide with the target inter-vehicle distance without decelerating the host vehicle, and discomfort is eliminated. Has been proposed (for example, Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-20503
[Problems to be solved by the invention]
Incidentally, the current inter-vehicle distance control device is provided with a switch (means) for inputting the set inter-vehicle distance between the host vehicle and the preceding vehicle in addition to the set traveling speed as described above. For example, in order to solve the problem of frequent interruption when the inter-vehicle distance is large in a relatively crowded situation, for example, the target inter-vehicle distance based on the traveling speed of the host vehicle is made smaller, Enter the set inter-vehicle distance so that it is larger. For example, when the set inter-vehicle distance is reduced, the inter-vehicle distance control gain is increased in order to respond to the driver's request to quickly reduce the inter-vehicle distance from the preceding vehicle. That is, it is set so that the inter-vehicle distance control gain increases as the change amount of the set inter-vehicle distance increases.
[0005]
However, for example, immediately after the input to reduce the set inter-vehicle distance, that is, when the inter-vehicle distance control gain is large, an interrupt occurs between the preceding vehicle and the host vehicle, and the inter-vehicle distance between the new preceding vehicle is the target inter-vehicle distance. If the distance is smaller than the distance, the control for increasing the inter-vehicle distance is performed in a state where the control gain remains large. That is, although the driver inputs to reduce the inter-vehicle distance, the inter-vehicle distance between the actual own vehicle and the preceding vehicle increases rapidly, causing a sense of discomfort.
[0006]
In order to solve the above-mentioned problem, the present invention increases the inter-vehicle distance control gain only when the direction of changing the set inter-vehicle distance is the same as the direction of the actual inter-vehicle distance control. It is an object of the present invention to provide an inter-vehicle distance control device that can dispel a sense of incongruity by matching actual control.
[0007]
[Means for Solving the Problems]
To achieve the above object, the inter-vehicle distance control apparatus of the present invention, along with the direction and distance control of the relative rates of change that would occur I accompanied changed set inter-vehicle distance input by the driver The gain of the inter-vehicle distance control is increased only when the direction of the change in the relative speed to be generated coincides and the set inter-vehicle distance is changed to be small .
[0008]
Incidentally, because the change of the direction of the relative velocity generated with the direction and distance control of the change in would occur I accompanied a change in the set inter-vehicle distance relative speed are the same, for example, the driver set The relative speed should change in the negative direction when it is desired to reduce the inter-vehicle distance. On the other hand, the relative speed change caused by the actual inter-vehicle distance control is in the negative direction. Yes.
[0009]
【The invention's effect】
And Thus, according to the inter-vehicle distance control apparatus of the present invention, generated with the direction and distance control of the relative rates of change that would occur I accompanied changed set inter-vehicle distance input by the driver Since the configuration is such that the gain of the inter-vehicle distance control is increased only when the direction of the change in the relative speed coincides and the set inter-vehicle distance is changed to be small , the driver's intention to input the set inter-vehicle distance and the actual control Since the gain increases only when the values match, there is no sense of incongruity.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a system configuration diagram showing an embodiment of a vehicle with a preceding vehicle follow-up travel control device to which the inter-vehicle distance control device of the present invention is applied. This vehicle is a rear wheel drive vehicle in which the rear wheels 1RL and 1RR are driving wheels and the front wheels 1FL and 1FR are driven wheels, and the driving torque of the engine 2 is transmitted to the rear wheels 1RL and 1RR via the automatic transmission 3. Is done.
[0011]
The rotation state, torque, output, etc. of the engine 2 can be controlled by the engine control device 11. Specifically, the engine rotation state, torque, output, etc. can be controlled by adjusting the throttle valve opening, idle valve opening, ignition timing, fuel injection amount, fuel injection timing, and the like.
The automatic transmission 3 can be controlled by a transmission control device 12. Specifically, by adjusting the working fluid pressure supplied to the clutch and brake in the automatic transmission 3, the selected gear ratio can be changed to obtain a desired reduction ratio.
[0012]
The wheels 1FL to 1RR are provided with wheel cylinders 4FL to 4RR constituting so-called disc brakes. The wheel cylinders 4FL to 4RR apply a braking force to the wheels 1FL to 1RR by the supplied brake fluid pressure. The braking force applied to each of the wheels 1FL to 1RR can be controlled by the braking fluid pressure control device 13. Specifically, for example, each wheel cylinder 4FL˜ is increased by increasing the brake fluid pressure as in the driving force control device (TCS) or decreasing the brake fluid pressure as in the anti-skid control device (ABS). The braking fluid pressure to 4RR can be adjusted and the braking force to each wheel 1FL-1RR can be controlled. The braking fluid pressure regulated in the braking fluid pressure control device 13 is supplied from a master cylinder 22 that is boosted by depressing the brake pedal 21.
[0013]
Each of these control devices controls the running state of the vehicle, and as a result, the running state can be controlled by adjusting the acceleration / deceleration, the longitudinal speed, etc. of the host vehicle.
Of course, these control devices can operate alone, but the overall function is governed by the automatic travel control device 10 including inter-vehicle distance control and preceding vehicle following travel control. The automatic travel control device 10 performs various arithmetic processes to control the travel state of the vehicle, thereby performing inter-vehicle distance control, preceding vehicle following travel control, and the like.
[0014]
In addition, the vehicle is provided with, for example, a CCD camera and the like, a state ahead of the host vehicle, for example, the state of the traveling lane, the presence or absence of the preceding vehicle, the distance to the preceding vehicle, the shape of the preceding vehicle, particularly the height direction of the preceding vehicle A front state detection device 16 that detects the size of the vehicle (hereinafter also simply referred to as height), a wheel speed sensor 17 that detects the rotational speed of each wheel 1FL to 1RR, and an acceleration that detects longitudinal and lateral acceleration generated in the vehicle. A sensor 18, a brake fluid pressure sensor 19 that detects the brake fluid pressure, and an accelerator opening sensor 20 that detects the amount of depression of the accelerator pedal are provided. In addition, this vehicle is provided with a navigation system 7 that detects position information of the vehicle by so-called GPS (Global Positoining System). Further, the vehicle is provided with a display and a speaker 23 for presenting the contents of control by the automatic travel control device 10 to an occupant, particularly a driver.
[0015]
Further, this vehicle is provided with a manual switch 9 for adjusting the traveling state of the host vehicle by a driver's manual input. Details of the manual switch 9 are shown in FIG. In the figure, reference numeral 9a is an automatic travel control start switch including inter-vehicle distance control and preceding vehicle following travel control, 9b is an automatic travel control release switch, 9c is a set inter-vehicle distance switch for inputting a set inter-vehicle distance, and 9d is a set travel. A set / coast switch for inputting a speed or changing a set travel speed in a deceleration direction. 9e is a resume / change switch for re-inputting a previous set travel speed or changing a set travel speed in an acceleration direction after canceling the automatic travel control. Accelerate switch. Of these, the set inter-vehicle distance switch 9c is not used to input a specific set inter-vehicle distance as a numerical value. For example, the set inter-vehicle distance switch 9c is used to increase or decrease the current inter-vehicle distance. When the most standard target inter-vehicle distance with respect to speed is set to “medium”, an input method such as “long” that makes the set inter-vehicle distance larger than that or “short” that makes the set inter-vehicle distance smaller than that is adopted. Yes. However, in the automatic travel control device 10, the set inter-vehicle distance input by the set inter-vehicle distance switch 9c is recognized as the set inter-vehicle distance dc.
[0016]
Next, calculation processing of the inter-vehicle distance control performed in the automatic travel control device 10 will be described with reference to the flowchart of FIG. This calculation process is executed by a timer interrupt every predetermined sampling time ΔT set to, for example, about 10 msec. In this flowchart, no particular communication step is provided, but the results obtained by the arithmetic processing are updated and stored in the storage device as needed, and necessary information and programs are read from the storage device as needed. Further, the above-described engine control device 11, transmission control device 12, and brake fluid pressure control device 13 communicate with each other at any time, and necessary information and commands are exchanged bidirectionally at any time.
[0017]
In this calculation process, first, in step S1, the longitudinal acceleration Xg and lateral acceleration Yg detected by the acceleration sensor 18, the wheel speed Vw _j (j = FL to RR) detected by the wheel speed sensor 17, and the accelerator opening. The accelerator opening degree Acc detected by the degree sensor 20, the braking fluid pressure Pm detected by the braking fluid pressure sensor 19, the set traveling speed Vc set by the manual switch 9, particularly the setting by the set inter-vehicle distance switch 9c Inter-vehicle distance information, own vehicle position information detected by the navigation system 7, inter-vehicle distance d with the preceding vehicle detected by the forward state detection device 16, engine drive torque Tw controlled by the engine control device 11 Read.
[0018]
Next, the process proceeds to step S2, and the traveling speed V of the host vehicle is calculated from the average value of the front left and right wheel speeds Vw _FL and Vw _FR among the wheel speeds Vw _j read in step S1.
Next, the process proceeds to step S3, where the difference value between the current value d _(n) and the previous value d _(n-1) of the inter-vehicle distance read in step S1 is divided by the predetermined sampling time ΔT. Then, the relative speed Vr between the host vehicle and the preceding vehicle is calculated.
[0019]
Next, the process proceeds to step S4, and a target inter-vehicle distance dr corresponding to the traveling speed V of the host vehicle calculated in step S2 is calculated. Specifically, the travel speed V of the host vehicle is multiplied by a predetermined control gain, and a predetermined control constant is summed. The control gain and the control constant are set in accordance with the set inter-vehicle distance requested by the driver inputted by the set inter-vehicle distance switch 9c of the manual switch 9.
[0020]
Next, the process proceeds to step S8, and the target travel speed Vs is calculated according to the arithmetic processing of FIG.
Next, the process proceeds to step S10, where the target acceleration by, for example, PID (proportional-differential-integral) control is calculated from the difference value between the target traveling speed Vs calculated in step S8 and the traveling speed V of the host vehicle calculated in step S2. Xgs is calculated.
[0021]
Next, the process proceeds to step S11. For example, when the target acceleration Xgs calculated in step S10 is negative, that is, when deceleration is required, a value obtained by multiplying the target acceleration Xgs by a brake specification coefficient, The larger one of the values obtained by multiplying the braking fluid pressure Pm read in step S1 by the brake specification coefficient is calculated as the target braking fluid pressure Pws _j . The brake specification coefficient is a coefficient determined by, for example, the friction coefficient between the disk rotor pads of each wheel, the wheel cylinder cross-sectional area, the disk rotor effective diameter, the tire rolling radius, and the like.
[0022]
Next, the process proceeds to step S12, and when the target acceleration Xgs calculated in step S10 is positive, that is, when acceleration is required, a value obtained by multiplying the target acceleration Xgs by a drive system specification variable, The larger one of the values obtained by multiplying the accelerator opening Acc read in step S1 by the drive system variable is calculated as the target drive torque Tes. The drive system specification variable is a variable determined by, for example, gear inertia, reduction ratio, transmission efficiency, engine characteristics, and the like.
[0023]
At the next step S13, the step S11 target braking fluid pressure Pws _j and the step S12 the target driving the brake fluid pressure control device a torque Tes 13 and the engine control apparatus 11 calculated in calculated in the transmission control device 12 And output an information presentation signal for target inter-vehicle distance control toward the display and speaker 23, and then return to the main program. For example, when the target distance between the vehicles is changed and controlled, for example, content such as “increase the distance between vehicles” is presented by voice or display before the information is presented by the display and the speaker 23.
[0024]
According to this calculation processing, except during the inter-vehicle distance shift control, the target acceleration Xgs is calculated from the difference between the set target travel speed Vs and the travel speed V of the host vehicle, and the target for achieving the target acceleration Xgs is calculated. The brake fluid pressure Pws _j and the target drive torque Tes are output to the brake fluid pressure control device 13, the engine control device 11, and the transmission control device 12, and an information presentation signal for target inter-vehicle distance control is output to the display and the speaker 23. Output to.
[0025]
Next, the calculation process of FIG. 4 performed in step S8 of the calculation process of FIG. 3 will be described. In this calculation process, first, in step S81, it is determined whether or not an input by the set inter-vehicle distance switch 9c is detected from the set inter-vehicle distance information of the set inter-vehicle distance switch 9c read in step S1 of the arithmetic process of FIG. If it is determined that an input from the set inter-vehicle distance switch 9c is detected, the process proceeds to step S82, and if not, the process proceeds to step S83.
[0026]
In step S82, the set inter-vehicle distance dc by the set inter-vehicle distance switch 9c is not changed from the set inter-vehicle distance switch 9c information read in step S1 of the calculation process of FIG. It is determined whether or not there is, and if the set inter-vehicle distance dc is the same, the process proceeds to step S83, and if not, the process proceeds to step S84.
[0027]
In step S84, the control gain change flag F is set to “1” and then the process proceeds to step S86.
On the other hand, in step S83, the absolute value of the difference value obtained by subtracting the inter-vehicle distance d between the host vehicle and the preceding vehicle read in step S1 of the calculation process of FIG. 3 from the set inter-vehicle distance dc is smaller than a predetermined value β. If the absolute value of the difference value is smaller than the predetermined value β, the process proceeds to step S85, and if not, the process proceeds to step S86.
[0028]
In step S85, the control gain change flag F is set to a reset state of “0”, and then the process proceeds to step S86.
In step S86, it is determined whether or not the control gain change flag F is in the set state. If the control gain change flag F is in the set state, the process proceeds to step S87. Then, the process proceeds to step S88.
[0029]
In step S87, the set inter-vehicle distance dc is divided by the inter-vehicle distance d between the host vehicle and the preceding vehicle read in step S1 of the calculation process of FIG. Migrate to
In step S89, it is determined from the set inter-vehicle distance information of the set inter-vehicle distance switch 9c read in step S1 of the calculation process of FIG. If dc is changed to a small value, the process proceeds to step S90, and if not, the process proceeds to step S91.
[0030]
In step S90, as shown in the control map shown in FIG. 5, the gain increase rate α is calculated according to the function f ₁ (γ) related to the inter-vehicle distance change rate γ calculated in step S87, and then the process proceeds to step S92. To do. The control map of FIG. 5, that is, the function f ₁ (γ) related to the inter-vehicle distance change rate γ is an area where the inter-vehicle distance change rate γ is “1” or more, that is, the set inter-vehicle distance dc with respect to the actual inter-vehicle distance d. The gain increase rate α is fixed to “1” and the inter-vehicle distance change rate γ is smaller than “1”, that is, the set inter-vehicle distance is changed smaller than the actual inter-vehicle distance d. In this case, the gain increase rate α is set to increase as the inter-vehicle distance change rate γ decreases. That is, since the set inter-vehicle distance dc has been changed to a small value in the determination of step S89, the process proceeds to step S90. Therefore, the inter-vehicle distance change rate γ is smaller than “1”, that is, the driver's intention to change the inter-vehicle distance. When the change direction of the set inter-vehicle distance dc relative to the actual inter-vehicle distance d, that is, the direction of the inter-vehicle distance control in the future, is the same, the gain increase rate α increases as the change amount of the set inter-vehicle distance dc increases. On the other hand, an area in which the inter-vehicle distance change rate γ is “1” or more, that is, the driver's intention to change the inter-vehicle distance and the change direction of the set inter-vehicle distance dc with respect to the actual inter-vehicle distance d, that is, the future direction of inter-vehicle distance control. Is different, the gain increase rate α is fixed to “1” regardless of the change amount of the set inter-vehicle distance dc.
[0031]
In step S91, as shown in the control map shown in FIG. 6, the gain increase rate α is calculated according to the function f ₂ (γ) related to the inter-vehicle distance change rate γ calculated in step S87. The process proceeds to S92. The control map of FIG. 6, that is, the function f ₂ (γ) related to the inter-vehicle distance change rate γ is an area where the inter-vehicle distance change rate γ is “1” or less, that is, the set inter-vehicle distance dc with respect to the actual inter-vehicle distance d. The gain increase rate α is fixed to “1” and the inter-vehicle distance change rate γ is larger than “1”, that is, the set inter-vehicle distance is greatly changed with respect to the actual inter-vehicle distance d. In this case, the gain increase rate α is set to increase as the inter-vehicle distance change rate γ increases. That is, as a result of the determination in step S89 that the set inter-vehicle distance dc has been greatly changed, the process proceeds to step S91, so that the inter-vehicle distance change rate γ is greater than “1”, that is, the driver's intention to change the inter-vehicle distance. When the change direction of the set inter-vehicle distance dc relative to the actual inter-vehicle distance d, that is, the direction of the inter-vehicle distance control in the future, is the same, the gain increase rate α increases as the change amount of the set inter-vehicle distance dc increases. On the other hand, the region where the inter-vehicle distance change rate γ is “1” or less, that is, the driver's intention to change the inter-vehicle distance and the change direction of the set inter-vehicle distance dc with respect to the actual inter-vehicle distance d, that is, the future direction of inter-vehicle distance control. Is different, the gain increase rate α is fixed to “1” regardless of the change amount of the set inter-vehicle distance dc.
[0032]
In step S88, the gain increase rate α is set to “1”, and then the process proceeds to step S92.
In the step S92, as shown in the control map shown in FIG. 7, in accordance with the function f ₃ (Vr) related to the relative velocity Vr calculated at step S3 of calculation process of FIG. 3, and calculates a gain increase rate beta. The control map of FIG. 7, that is, the function f ₃ (Vr) related to the relative speed Vr is a region where the relative speed Vr is “0” or more, that is, the relative speed Vr is a positive value. The gain increase rate β is fixed to “1” when they are separated from each other, the region where the relative speed Vr is less than “0”, that is, the relative speed Vr is a negative value, and the host vehicle and the preceding vehicle approach each other. In such a case, the gain increase rate β is set to increase as the relative speed Vr decreases (the absolute value of the relative speed Vr increases). That is, when the set inter-vehicle distance dc is changed to be small, the relative speed Vr is a positive value, that is, when the host vehicle and the preceding vehicle are separated from each other, the gain increase rate β is Fixed to “1”. On the other hand, the absolute value of the relative speed Vr is changed only when the set inter-vehicle distance dc is changed to a small value, the relative speed Vr is also a negative value, and the inter-vehicle distance between the host vehicle and the preceding vehicle is small. As the value increases, the gain increase rate β increases. That is, the set inter-vehicle distance dc is changed to a small value, and the direction of the change in the relative speed that will occur in accordance with the change of the set inter-vehicle distance dc input by the driver, and the relative speed generated by the actual inter-vehicle distance control. The gain increase rate β is set to be large only when the direction of the change is the same, that is, the control gain is increased.
[0033]
Next, the process proceeds to step S93, and the gain increase rate α set in steps S88, S90, and S91 and the gain increase rate β set in step S92 are set to the inter-vehicle distance feedback proportional control gain initial value Kp ₀ . Multiply it and calculate it as the inter-vehicle distance feedback proportional control gain Kp.
Next, the process proceeds to step S94, the target travel speed Vs is calculated as follows, and then the process proceeds to step S9 of the calculation process of FIG. Here, first, in step S93, a difference value between the actual inter-vehicle distance d read in step S1 of the arithmetic processing of FIG. 3 and the target inter-vehicle distance dr calculated in step S4 of the arithmetic processing of FIG. 3 is set. The value obtained by multiplying the vehicle distance feedback proportional control gain Kp, the value obtained by multiplying the relative speed Vr calculated in step S3 of the calculation process of FIG. 3 by the differential control gain Kd, and the traveling speed V of the host vehicle. The reference target travel speed Vs ₀ is calculated from the reference target travel speed Vs _0, and the smaller one of the reference target travel speed Vs ₀ and the set travel speed Vc read in step S1 of the calculation process of FIG. 3 is set as the target travel speed Vs. Set.
[0034]
According to this calculation process, when the set inter-vehicle distance dc is changed, the gain increase rate α corresponding to the inter-vehicle distance change rate γ is set, and the gain increase rate β corresponding to the relative speed Vr is set. The gain increase rate α and the gain increase rate β are multiplied by the inter-vehicle distance feedback proportional control gain initial value Kp ₀ to calculate the inter-vehicle distance feedback proportional control gain Kp, and the target inter-vehicle distance Vs is calculated using the inter-vehicle distance feedback proportional control gain Kp. Is calculated. At this time, when the driver's intention to change the inter-vehicle distance, that is, when the change direction of the set inter-vehicle distance dc and the direction of the inter-vehicle distance control are the same, the gain increase rate α increases as the change amount of the set inter-vehicle distance dc increases. However, when the driver's intention to change the inter-vehicle distance, that is, when the direction of changing the set inter-vehicle distance dc is different from the direction of the inter-vehicle distance control in the future, it is fixed at “1” regardless of the change amount of the set inter-vehicle distance dc. Is done. The gain increase rate β is determined when the direction of change in the relative speed accompanying the change in the set inter-vehicle distance dc is the same as the direction of change in the relative speed generated by the inter-vehicle distance control. When the intention to change the distance and the actual inter-vehicle distance control are the same, the absolute value of the relative speed Vr increases as the absolute value of the relative speed Vr increases, but when both directions are different, that is, the driver's intention to change the inter-vehicle distance and the actual inter-vehicle distance control. Is different from the relative speed Vr, it is fixed at “1”. Accordingly, the inter-vehicle distance feedback proportional control gain Kp calculated by multiplying the gain increase rate α and the gain increase rate β is also set when the driver's intention to change the inter-vehicle distance and the inter-vehicle distance control are the same. However, when the driver's intention to change the inter-vehicle distance and the future inter-vehicle distance control are different, the change amount of the set inter-vehicle distance dc and the absolute value of the relative speed Vr are larger. Regardless, the inter-vehicle distance feedback proportional control gain initial value Kp ₀ is fixed.
[0035]
As described above, the inter-vehicle distance feedback proportional control gain Kp is used to calculate the target travel speed Vs by multiplying the difference value between the target inter-vehicle distance dr and the actual inter-vehicle distance d. The larger the feedback proportional control gain Kp, the greater the effect of correcting the deviation between the target inter-vehicle distance dr and the actual inter-vehicle distance d. The inter-vehicle distance feedback proportional control gain Kp becomes larger as the change amount of the set inter-vehicle distance dc and the absolute value of the relative speed Vr are larger when the driver's intention to change the inter-vehicle distance and the future inter-vehicle distance control are the same. Therefore, the inter-vehicle distance is quickly controlled in the direction in which the driver changes the inter-vehicle distance. On the other hand, when the driver's intention to change the inter-vehicle distance differs from the inter-vehicle distance control in the future, the inter-vehicle distance feedback proportional control gain Kp is the inter-vehicle distance feedback regardless of the change amount of the set inter-vehicle distance dc and the absolute value of the relative speed Vr. Since the proportional control gain initial value Kp ₀ is fixed, the responsiveness of the inter-vehicle distance control is low.
[0036]
In FIG. 8, the set inter-vehicle distance dc is changed from “medium” to “short” by the set inter-vehicle distance switch 9c, and at that time, the inter-vehicle distance d between the host vehicle and the preceding vehicle has not changed from before. The state of the change of the inter-vehicle distance d, the engine torque, the vehicle acceleration, and the traveling speed V is shown. Thus, when the inter-vehicle distance d between the host vehicle and the preceding vehicle has not changed from before the change of the set inter-vehicle distance dc, the inter-vehicle distance change rate γ becomes smaller than “1” when the set inter-vehicle distance dc becomes small. The gain increase rate α becomes a large value according to the control map of FIG. 5, and when the relative speed Vr becomes a negative value to reduce the inter-vehicle distance d, the gain increase rate β becomes large according to the control map of FIG. Value. As a result, the engine torque increases rapidly, the vehicle accelerates and the traveling speed increases, and as a result, the inter-vehicle distance d between the host vehicle and the preceding vehicle decreases.
[0037]
On the other hand, FIG. 8 shows that while the set inter-vehicle distance switch 9c is changed from “medium” to “short” by the set inter-vehicle distance switch 9c, A state in which the inter-vehicle distance d, the engine torque, the vehicle acceleration, and the traveling speed V change when the inter-vehicle distance d between the new preceding vehicle and the host vehicle becomes smaller than the newly set inter-vehicle distance dc is shown. It is. When the inter-vehicle distance d between the host vehicle and the preceding vehicle becomes smaller than the new set inter-vehicle distance dc while the set inter-vehicle distance dc is changed to be small in this way, the inter-vehicle distance change rate γ becomes “1” or more, and FIG. According to the control map of 5, the gain increase rate α is fixed to “1”. On the other hand, with the change in the set inter-vehicle distance dc, the target inter-vehicle distance dr is set to be small, but the inter-vehicle distance d between the host vehicle and the preceding vehicle is smaller than the new set inter-vehicle distance dc, so the target travel speed Vs decreases. Become a trend. As a result, the engine torque is reduced, the vehicle is decelerated, and the traveling speed is also reduced, so that the relative speed Vr becomes a separated side, that is, a positive value. Accordingly, the gain increase rate α used to calculate the target travel speed Vs is fixed to “1” and the gain increase rate β is also fixed to “1”, that is, the inter-vehicle distance feedback proportional control gain Kp is the inter-vehicle distance. Since the distance feedback proportional control gain initial value Kp ₀ is fixed, the inter-vehicle distance increases only slowly. That is, when the driver's intention to change the inter-vehicle distance is different from the inter-vehicle distance control in the future, the vehicle behavior becomes gradual, so that the uncomfortable feeling can be eliminated.
[0038]
From the above, the forward state detection device 16 of FIG. 1 and the step S1 of the arithmetic processing of FIG. 2 constitute the inter-vehicle distance detection means of the present invention, and hereinafter the manual switch 9 of FIG. 1 and the set inter-vehicle distance of FIG. The distance switch 9c constitutes a set inter-vehicle distance input means, step S4 of the arithmetic processing in FIG. 3 constitutes a target inter-vehicle distance setting means, and the arithmetic processing steps S8 to S13 in FIG. 3 and the entire arithmetic processing in FIG. Constitutes an inter-vehicle distance control means.
[0039]
In the embodiment described above, it is possible to input a set inter-vehicle distance such as whether it is larger or smaller than a standard target inter-vehicle distance value corresponding to the traveling speed of the own vehicle. Although the target inter-vehicle distance is set based on the traveling speed of the vehicle, the set inter-vehicle distance and the target inter-vehicle distance may be regarded as the same in terms of the concept. That is, for the driver, the set inter-vehicle distance is the final target inter-vehicle distance. However, since the driver does not have a target value of the standard inter-vehicle distance according to the traveling speed of the own vehicle, the control side has a standard inter-vehicle distance according to the traveling speed of the own vehicle. The logic of the present invention is that the target inter-vehicle distance should be set in consideration of the set inter-vehicle distance input by the driver.
[Brief description of the drawings]
FIG. 1 is a vehicle configuration diagram showing an example of a vehicle with preceding vehicle follow-up travel control equipped with a braking control device of the present invention.
FIG. 2 is an explanatory diagram of the manual switch of FIG. 1;
FIG. 3 is a flowchart showing a calculation process for inter-vehicle distance control performed by the automatic travel control device of FIG. 1;
4 is a flowchart showing a subroutine calculation process performed in the calculation process of FIG. 3; FIG.
FIG. 5 is a control map used in the arithmetic processing of FIG.
6 is a control map used in the arithmetic processing of FIG.
7 is a control map used in the arithmetic processing of FIG.
8 is an explanatory diagram of the operation of the arithmetic processing of FIGS. 3 and 4. FIG.
9 is an explanatory diagram of the operation of the arithmetic processing of FIGS. 3 and 4. FIG.
[Explanation of symbols]
1FL to 1RR is a wheel 2 is an engine 3 is an automatic transmission 4FL to 4RR is a wheel cylinder 7 is a navigation system 9 is a manual switch 10 is an automatic travel control device 11 is an engine control device 12 is a transmission control device 13 is a brake fluid pressure control The device 16 is a forward state detection device 17, the wheel speed sensor 18, the acceleration sensor 19, the brake fluid pressure sensor 20, the accelerator opening sensor 21, the brake pedal 22, the master cylinder 23, a display and a speaker.

Claims (2)

Upon controlled by a predetermined gain to match the inter-vehicle distance between the preceding vehicle and the subject vehicle to a target following distance, the change in the likely will the relative velocity occurring I accompanied a change in the set inter-vehicle distance input by the driver The inter-vehicle distance control is characterized by increasing the inter-vehicle distance control gain only when the direction of the vehicle coincides with the direction of the change in relative speed generated by the inter-vehicle distance control and the set inter-vehicle distance is changed to a small value. Control device. An inter-vehicle distance detecting means for detecting an inter-vehicle distance between the host vehicle and the preceding vehicle, a set inter-vehicle distance input means for the driver to input a set inter-vehicle distance between the own vehicle and the preceding vehicle, and at least the own vehicle and the preceding vehicle A target inter-vehicle distance setting means for setting a target inter-vehicle distance between the host vehicle and a preceding vehicle based on any one of the traveling states and the set inter-vehicle distance input by the set inter-vehicle distance input means; and the speed of the own vehicle is controlled. And a vehicle distance control means for controlling the vehicle distance between the host vehicle and the preceding vehicle so as to coincide with the target vehicle distance set by the target vehicle distance setting means. Direction of change in relative speed when controlling the inter-vehicle distance between the vehicle and the preceding vehicle to match the target inter-vehicle distance, and the set inter-vehicle distance between the host vehicle and the preceding vehicle input by the set inter-vehicle distance input means When the direction of change in the relative speed that would occur I accompanied the change is consistent and change the set inter-vehicle distance is small, as the absolute value of the relative speed is large, the control gain of the adaptive cruise control The inter-vehicle distance control device characterized by increasing the distance.

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