JP2770533B2 - Vehicle cruise control system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a follow-up running control device for a vehicle that causes a self-vehicle to follow a preceding vehicle, and more particularly to a technique for improving the reliability thereof. It is.

2. Description of the Related Art An example of a follow-up traveling control device is described in Japanese Patent Application Laid-Open No. Sho 60-215432. This includes (a) a vehicle ahead judging means for judging whether or not a vehicle exists in front of the own vehicle;
(B) an inter-vehicle distance sensor that detects an inter-vehicle distance between the host vehicle and the preceding vehicle in response to an electromagnetic wave from the preceding vehicle; and (c) an inter-vehicle distance detection unit based on the inter-vehicle distance detected by the inter-vehicle distance sensor. If it is determined that there is a vehicle ahead, the vehicle is added to the vehicle so as to follow the vehicle.
The acceleration / deceleration device for controlling the acceleration / deceleration device for decelerating, but when it is determined that the vehicle does not exist, the host vehicle includes acceleration / deceleration device control means for controlling the acceleration / deceleration device to maintain the vehicle speed at the vehicle speed set by the driver. It is configured.

SUMMARY OF THE INVENTION Problems to be Solved by the Invention Generally, a follow-up cruise control device is based on the premise that, when there is a forward vehicle to be tracked by the own vehicle, the forward vehicle always exists within a detectable area of the inter-vehicle distance sensor. Although it is designed, according to the research of the present applicant, the preceding vehicle deviates from the detectable area in the vertical direction of the own vehicle due to the inclination of the road surface on which the own vehicle is traveling, and the above assumption does not hold It turns out that there is.

For example, when the vehicle shifts from a flat road to an uphill road as in the vehicle A shown in FIG.
As in the case of transition from a downhill road to a flat road, the inclination angle of the road surface (represented by θ in the figure) is in a positive direction (a positive direction when the road surface changes the traveling direction of the vehicle upward, and a downward direction). When it is changed, it suddenly increases in a negative direction), and the preceding vehicle deviates upward from a detectable area of the inter-vehicle distance sensor (a finite area extending linearly or planarly in front of the own vehicle).

In the drawing, the inclination angle change rate, which is the amount of change of the inclination angle θ per unit traveling distance of the vehicle, is represented by dθ / dl. In addition, the inclination angle of the road surface is drawn considerably large in the figure, but this is for the purpose of easily explaining how the preceding vehicle deviates from the detectable area due to the inclination of the road surface, and actually, it is not so large. Not big.

If the preceding vehicle deviates upward from the detectable area, the following distance sensor will detect the road surface as the preceding vehicle,
Even if the inter-vehicle distance hardly changes, the inter-vehicle distance sensor makes an erroneous determination that the own vehicle has suddenly approached the preceding vehicle, and according to the determination result, Even if the inter-vehicle distance sensor does not actually detect the preceding vehicle, an erroneous determination that there is a preceding vehicle is made. As a result, there arises a problem that the own vehicle can be decelerated without necessity to increase the inter-vehicle distance.

In addition, when the vehicle moves from an uphill road to a flat road like the own vehicle B shown in FIG. When the angle suddenly increases in the negative direction, the preceding vehicle deviates downward from the detectable range of the following distance sensor, so that the following distance sensor detects, for example, the sky, and the preceding vehicle presence / absence determining means performs tracking. An incorrect determination is made that the preceding vehicle to be present does not exist even though it actually exists. If the constant speed traveling control based on the set vehicle speed is performed instead of the following traveling control in accordance with this determination result, there arises a problem that the own vehicle is inappropriately accelerated to increase the vehicle speed of the own vehicle to the set vehicle speed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle follow-up running control device capable of preventing inappropriate running control of a host vehicle due to a road surface inclination.

Means for Solving the Problems The gist of the present invention is to provide an acceleration / deceleration device for accelerating and decelerating the own vehicle so as to cause the own vehicle to follow the preceding vehicle as shown in FIG. The following vehicle running control device to be controlled follows the own vehicle based on (a) an inter-vehicle distance sensor that detects an inter-vehicle distance between the own vehicle and a preceding vehicle, and (b) an inter-vehicle distance detected by the inter-vehicle distance sensor. Acceleration / deceleration device control means for performing follow-up traveling control for controlling the acceleration / deceleration device to perform traveling; and (c) an inclination angle at which the inclination angle of the road surface on which the vehicle is traveling changes per unit traveling distance or per unit time. Inclination angle change amount detecting means for detecting a change amount,
(D) connected to the inclination angle change amount detection means and the acceleration / deceleration device control means, to follow the acceleration / deceleration device control means when the inclination angle change amount detected by the inclination angle change amount detection means is equal to or more than a set amount; Control prohibiting means for prohibiting traveling control.

In the vehicle following travel control device according to the present invention, the change amount of the inclination angle of the road surface on which the own vehicle is traveling is detected by the inclination angle change amount detecting means, and the change of the inclination angle is controlled by the control inhibiting means. When the amount is equal to or larger than the set amount, the following travel control is prohibited.

One aspect of the control prohibiting means is that the change amount of the inclination angle is equal to or more than the first set amount and the change amount of the inter-vehicle distance that the inter-vehicle distance changes per unit traveling distance or per unit time is equal to or more than the second set amount. In this mode, the following control is prohibited by the acceleration / deceleration device control means.

After the control prohibition means prohibits the following travel control, it is necessary to cause the own vehicle to perform a specific travel.
For this purpose, for example, the current state in which the acceleration / deceleration device control means maintains the vehicle speed or the inter-vehicle distance of the own vehicle to a value at a time when the inter-vehicle distance sensor may no longer detect the preceding vehicle after the prohibition of the following travel control. It is desirable to perform maintenance traveling control, deceleration traveling control at a predetermined deceleration, manual traveling control based on a driver's operation, and the like.

As described above, according to the present invention, inappropriate traveling control of the host vehicle due to the inclination of the road surface is avoided, so that the effect of improving the reliability of the following traveling control device is obtained.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

The following cruise control device according to an embodiment of the present invention includes a computer 10 as shown in FIG. Computer
Reference numeral 10 includes a CPU, a ROM, a RAM, a bus, an input interface, an output interface, and the like. The input interface includes an inter-vehicle distance sensor 12 for detecting the inter-vehicle distance between the preceding vehicle and the own vehicle, a vehicle speed sensor 14 for detecting the speed of the own vehicle, an inclination angle sensor 16 for detecting the inclination angle of the road surface, and an acceleration / deceleration of the own vehicle. Is connected to the G sensor 18 for detecting the On the other hand, the output interface is connected to a brake actuator 20 for controlling brakes of four wheels of the host vehicle and a throttle actuator 22 for controlling a throttle valve provided in an intake manifold of the engine.

The ROM stores various control programs, including a follow-up running control routine shown by a flowchart in FIG. The ROM also stores two maps that define the relationship between the inter-vehicle distance and the target vehicle speed represented by a graph in FIG. An approach map used for follow-up running control when the preceding vehicle relatively approaches the own vehicle,
This is stored as a non-approaching map used for follow-up running control when the preceding vehicle is relatively separated from the own vehicle or when the inter-vehicle distance is constant. Hereinafter, the manner in which the following running control is performed will be described.

The routine of FIG. 3 is executed every predetermined time. In each execution of this routine, first, in step S1 (hereinafter simply referred to as S1; the same applies to other steps),
The current inter-vehicle distance is measured based on the output signal of the inter-vehicle distance sensor 12, and is stored in the RAM of the computer 10. Subsequently, in S2, the approach flag indicating that the vehicle is approaching in the set state, and the approach flag indicating that the vehicle is not approaching in the reset state is reset. At the time of execution, it is determined whether or not it is shorter than the preceding inter-vehicle distance stored as the current inter-vehicle distance, thereby determining whether or not the vehicle is currently approaching. If so, the approach flag is set in S4,
Otherwise, the execution of S4 is bypassed and the approach flag is kept reset.

In any case, thereafter, in S5, the vehicle speed sensor 14
The own vehicle speed, which is the current vehicle speed, is measured based on the output signal of the vehicle, and is stored in the RAM. Subsequently, in S6, the current inclination angle of the road surface is measured based on the output signal of the inclination angle sensor 16 and the output signal of the G sensor 18. Since the output signal of the inclination sensor 16 is affected not only by the inclination angle of the road surface but also by the acceleration / deceleration of the own vehicle, the G sensor 18 is used to remove the influence of the acceleration / deceleration from the output signal. is there. In S6, the current tilt angle is further stored in the RAM.

In S7, the rate of change of the road surface inclination angle is calculated. A value obtained by subtracting the front inclination angle stored in the RAM as the current inclination angle at the previous execution of this routine from the current inclination angle is calculated, and the value is calculated by the product of the own vehicle speed and the execution cycle of this routine. The value obtained by the division is used as the inclination angle change rate as the inclination angle change amount. The product of the own vehicle speed and the execution cycle is used as the distance traveled by the own vehicle during the execution of this routine once. Thereafter, in S8, it is determined whether or not the absolute value of the inclination angle change rate is larger than a positive threshold value α as a set amount. It is determined whether or not the inclination angle at the position of the vehicle on the road surface suddenly increases in the positive direction or suddenly increases in the negative direction. This time, assuming that the absolute value of the inclination angle change rate is not larger than the threshold value α, the determination result is NO, and in S9,
A prohibition flag indicating that the follow-up traveling control is prohibited in the set state and not prohibiting in the reset state is reset.

Subsequently, a target vehicle speed corresponding to the current inter-vehicle distance is determined in S10. In this case, the target vehicle speed is determined using the non-approaching map when the vehicle is in the non-approaching state and the approaching map when the vehicle is in the approaching state in the same manner as the previous time. Is in the approaching state this time, or when it was in the approaching state last time but is in the non-approaching state this time, that is, this time when shifting from the non-approaching state to the approaching state, or from the approaching state to the non-approaching state When the transition is made, the target vehicle speed is determined by a method different from the above case. In addition, the applicant of the present invention has adopted
This is described in detail in the specification filed on Jan. 24, 2012, and will be briefly described here.

If this time is a transition from the non-approaching state to the approaching state, the target vehicle speed is set to the value stored as the target vehicle speed at the previous execution of this routine. Also, from the time of transition,
Until the current inter-vehicle distance decreases until the target vehicle speed decreases to the corresponding inter-vehicle distance in the approaching graph shown in FIG.
The current target vehicle speed is set as the previous target vehicle speed. On the other hand, if this time is a transition from the approaching state to the non-approaching state, the target vehicle speed is set to the value stored as the target vehicle speed at the previous execution of this routine. Also,
The current target vehicle speed is set to be the previous target vehicle speed until the current inter-vehicle distance is increased to the corresponding inter-vehicle distance in the non-approaching graph shown in FIG. Has become.

An upper limit is set for the target vehicle speed determined by each of these two maps, and the upper limit is a vehicle speed set by the driver. Therefore, when the current inter-vehicle distance is longer than the inter-vehicle distance corresponding to the set vehicle speed, in practice, constant-speed traveling is performed instead of following traveling.

Further, in the same step, the target vehicle speed determined as described above is stored in the RAM.

Thereafter, in S12, the target acceleration / deceleration of the host vehicle is calculated based on the target vehicle speed and the host vehicle speed. Then, S1
In 3, the control amount of the brake actuator 20 is calculated based on the current acceleration / deceleration of the vehicle based on the output signal of the G sensor 18 and the target acceleration / deceleration, and the brake actuator 20 is controlled by the control amount. , S1
In 4, the control amount of the throttle actuator 22 is calculated based on the current acceleration / deceleration and the target acceleration / deceleration, and the throttle actuator 22 is controlled by the control amount. If the above execution is repeated many times, if it is determined that the inter-vehicle distance is long enough or that there is no preceding vehicle to track because there is no actual preceding vehicle, the own vehicle is set. The vehicle travels at a constant speed according to the vehicle speed. On the other hand, if it is determined that there is a preceding vehicle to be tracked because the inter-vehicle distance is not so long, the relationship between the current inter-vehicle distance and the own vehicle speed is shown in FIG. The current acceleration / deceleration of the own vehicle is controlled so as to be maintained at the same speed. As a result, the own vehicle performs acceleration, deceleration, start, and stop following the preceding vehicle.

The case where the absolute value of the inclination angle change rate is not larger than the threshold value α has been described above. If the absolute value is larger than the threshold value α, the determination result of S8 is YES, and the steps after S16 are executed.

In S16, it is determined whether the prohibition flag is set. Assuming that this is not the case at present, the determination result is NO, and the inter-vehicle distance change rate as the inter-vehicle distance change amount is calculated in S17. The difference between the current inter-vehicle distance and the preceding inter-vehicle distance stored in the RAM as the current inter-vehicle distance at the time of the previous execution of this routine is used as the absolute value of the inter-vehicle distance change rate. Subsequently, in S18, it is determined whether or not the absolute value of the inter-vehicle distance change rate is greater than a positive threshold value β. Otherwise, the result of the determination is NO, the steps after S9 are executed, and the following traveling control is performed.
If so, the result of the determination is YES, the prohibition flag is set in S19, and then S12 is executed. In S12, since the previous target vehicle speed stored as the target vehicle speed at the time of the previous execution of this routine is set as the current target vehicle speed, the execution of S12 to S14, S1 to S8, and S16 to S19 is repeated many times. For example, the current status traveling control for maintaining the own vehicle speed at the target vehicle speed at the time when it is expected that the inter-vehicle distance sensor 12 no longer detects the preceding vehicle is performed.

Note that once the prohibition flag is set, the vehicle can follow the vehicle even if the absolute value of the inclination angle change rate is greater than the threshold value α but the absolute value of the inter-vehicle distance change rate is less than the threshold value β. Without returning to the control, the control returns to the following running control only when the absolute value of the inclination angle change rate shifts to the state where the absolute value is equal to or smaller than the threshold value α.

If the vehicle ahead and your vehicle run on the same road surface,
The inclination angle at the position of the front vehicle on the road surface and the inclination angle at the position of the own vehicle also change in substantially the same pattern, but since the front vehicle passes through each position on the road surface before the own vehicle, the The change in the inclination angle appears before the change in the inclination angle at the position of the host vehicle. Therefore, when the absolute value of the inclination angle change rate of the own vehicle reaches the threshold value α, the change amount of the inclination angle of the preceding vehicle (the change amount with respect to the road surface that has traveled until the change in the inclination angle starts to appear). ) Is estimated to be larger than the change amount of the inclination angle of the own vehicle.
It is determined that there is a possibility that the vehicle has deviated from the twelve detectable regions in the vertical direction of the own vehicle.

However, in this embodiment, the follow-up traveling control is not immediately prohibited because of the possibility, but only after the fact that the absolute value of the inter-vehicle distance change rate is larger than the threshold value β is confirmed. Following running control is prohibited. This means that if the absolute value of the inclination angle change rate is equal to or greater than the threshold value α, the preceding vehicle does not always deviate from the detectable area of the inter-vehicle distance sensor 12, for example, if the current inter-vehicle distance is short, the inclination angle This is because even if the absolute value of the change rate is larger than the threshold value α, it is considered that the following distance sensor 12 may continue to detect the preceding vehicle. If two or more possible events are determined as in the present embodiment, the effect of improving the accuracy of determining the possibility or not is obtained.

As is apparent from the above description, in the present embodiment, the following traveling control is performed only when the preceding vehicle is actually detected by the following distance sensor 12, so that the reliability of the following traveling control device is improved. .

It should be noted that, in addition, it is determined whether or not there is a possibility that the preceding vehicle does not exist in the detectable area of the following distance sensor 12,
Instead of taking into account both the inclination angle change rate and the inter-vehicle distance change rate, it is possible to take into account only the inter-vehicle distance change rate, but in this case, for example, during follow-up traveling, When a third vehicle traveling in the same direction as the own vehicle and the preceding vehicle intrudes suddenly, it is determined that the preceding vehicle may not be present in the detection area, and the current state traveling control is performed. Is temporarily performed, and then follow-up running control is performed. That is, although it is necessary to increase the inter-vehicle distance promptly, there is a possibility that the inter-vehicle distance between the own vehicle and the third vehicle may be temporarily reduced due to the temporary current state running control. There is. However, in the present embodiment, when the third vehicle enters the vehicle in a state where the absolute value of the inclination angle change rate does not exceed the threshold value α, the preceding vehicle is determined based on the inter-vehicle distance change rate. It is not determined whether or not there is a possibility that the vehicle does not exist within the detectable region of the vehicle. Therefore, the follow-up traveling control is still performed, and the inter-vehicle distance between the own vehicle and the third vehicle is rapidly increased. Let me do.

As is apparent from the above description, in the present embodiment, the brake actuator 20, the throttle actuator 22 and the like constitute an acceleration / deceleration device, and the portion of the computer 10 that executes S1 to S5 and S10 in FIG. The acceleration / deceleration device control means of the type that selectively performs the following traveling control, the constant speed traveling control, and the current state traveling control in cooperation with the sensor 18, comprises the inclination angle sensor 16, the G sensor 18, and the computer.
The part executing S6 and S7 in FIG. 3 cooperates with each other to constitute the inclination angle change amount detecting means,
The part that executes S8, S9 and S16 to S19 in FIG. 3 constitutes the control prohibiting means.

In the above-described embodiment, the status quo running control is
The target vehicle speed was assumed to be the size of the time when the inter-vehicle distance sensor 12 could no longer detect the preceding vehicle,
When the continuation time of the current status maintenance control is longer than the reference value, the own vehicle may be decelerated at a deceleration equivalent to the engine brake, for example.

In the above embodiment, the acceleration / deceleration of the host vehicle is G
Although it was directly detected based on the output signal of the sensor 18,
It may be detected indirectly based on the output signal of the vehicle speed sensor 14.

In the above-described embodiment, both the case where the preceding vehicle may have deviated from the detectable area of the inter-vehicle distance sensor 12 above the own vehicle and the case where there is a possibility that the preceding vehicle has deviated below may be determined. However, only one of them may be determined.

Further, in the above embodiment, in consideration of not only the inclination angle change rate of the own vehicle but also the inclination angle change rate of the preceding vehicle (a value estimated from the inclination angle change rate of the own vehicle), the preceding vehicle is connected to the inter-vehicle distance sensor 12. The possibility existence determination whether or not there is a possibility that it does not exist in the detectable area of the has been performed,
It is possible to take into account only the rate of change of the inclination angle of the own vehicle. The amount by which the height of the detectable area at the position of the preceding vehicle of the inter-vehicle distance sensor 12 changes due to the change in the inclination angle of the own vehicle is the difference between the change amount of the inclination angle of the own vehicle and the inter-vehicle distance between the own vehicle and the preceding vehicle. Because it is determined by the product, it is estimated that whether or not the preceding vehicle deviates from the detectable area of the inter-vehicle distance sensor 12 depends more on the change in the inclination angle of the own vehicle than on the change in the inclination angle of the preceding vehicle.

Further, in the above-described embodiment, the inclination angle change rate is used only for determining the possibility of presence or absence.
For example, it can also be used when determining the control amounts of the brake actuator 20, the throttle actuator 22, and the like.

In addition, the present invention can be carried out in various modified and improved forms based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a block diagram conceptually showing the configuration of the present invention. FIG. 2 is a block diagram showing a configuration of a vehicle following travel control device according to one embodiment of the present invention. FIG. 3 is a flowchart showing a follow-up running control routine stored in a ROM of the computer in FIG. FIG. 4 is a graph showing the relationship between the following distance stored in the ROM and the target vehicle speed. FIG. 5 is a diagram for explaining a case where the preceding vehicle deviates from the detectable area of the following distance sensor due to the inclination of the road surface. 10: computer, 12: inter-vehicle distance sensor 14: vehicle speed sensor, 16: inclination sensor 18: G sensor 20: brake actuator 22: throttle actuator

Continuation of the front page (72) Inventor Toshiyasu Katsuno 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (56) References JP-A-62-265037 (JP, A) JP-A-62-265038 (JP) , A) JP-A-62-8836 (JP, A) JP-A-61-150835 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60K 31/00-31/18

Claims (1)

(57) [Claims] 1. A vehicle follow-up running control device for controlling an acceleration / deceleration device for accelerating and decelerating the own vehicle in order to cause the own vehicle to follow the preceding vehicle. An inter-vehicle distance sensor that detects an inter-vehicle distance of the vehicle, and an acceleration / deceleration device control that performs a following traveling control that controls the acceleration / deceleration device to cause the own vehicle to perform the following traveling based on the inter-vehicle distance detected by the inter-vehicle distance sensor. Means for detecting an inclination angle change amount in which the inclination angle of the road surface on which the vehicle is traveling has changed per unit traveling distance or per unit time; and those inclination angle change amount detection means and acceleration / deceleration. A control prohibition unit connected to the device control unit and configured to prohibit the follow-up traveling control to the acceleration / deceleration device control unit when the inclination angle change amount detected by the inclination angle change amount detection unit is equal to or more than a set amount. Special Adaptive cruise controller according to.