JP2008120181A - Travel control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress that a vehicle following a preceding vehicle causes hunting. <P>SOLUTION: This travel control device for the vehicle has a preceding vehicle speed measurement means measuring a vehicle speed of a preceding vehicle traveling in front of one's own vehicle, and controls acceleration/deceleration of the own vehicle to nearly equalize an inter-vehicle distance between the own vehicle and the preceding vehicle with a preset set inter-vehicle distance based on the vehicle speed measured by the preceding vehicle speed measurement means. The travel control device has a vehicle speed change calculation means calculating a degree of a change per prescribed time of the vehicle speed measured by the preceding vehicle speed measurement means, and controls a travel of the own vehicle by an acceleration amount or a deceleration amount smaller than an acceleration amount or a deceleration amount necessary to nearly equalize the inter-vehicle distance to the preceding vehicle with the set inter-vehicle distance when the change degree of the vehicle speed per the prescribed time calculated by the vehicle speed change calculation means is larger than a prescribed change degree. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle travel control apparatus, and belongs to a technical field of vehicle travel control that controls the travel of a host vehicle so as to follow the preceding vehicle while maintaining a substantially constant distance from the preceding vehicle.

  2. Description of the Related Art In recent years, when a preceding vehicle is traveling in front of a host vehicle, a vehicle travel control device for causing the host vehicle to follow the preceding vehicle while maintaining a substantially constant distance from the preceding vehicle. It is being used. As such an apparatus, there exists a thing of patent document 1, for example.

JP 2005-170310 A

  However, when the degree of change in the vehicle speed of the preceding vehicle is large, specifically, the preceding vehicle accelerates or decelerates in a short time, and the acceleration or deceleration is different or not the same acceleration amount (deceleration amount). When it is performed regularly or periodically, if priority is given to maintaining the inter-vehicle distance from the preceding vehicle substantially constant, the degree of change in the vehicle speed of the host vehicle increases as in the preceding vehicle. Therefore, the host vehicle may cause hunting while following the preceding vehicle.

  Therefore, the present invention provides a travel control device for a vehicle that can suppress hunting of the host vehicle following the preceding vehicle even when the degree of change in the vehicle speed of the preceding vehicle is large. This is the issue.

  In order to solve the above-mentioned problem, the invention according to claim 1 of the present application includes a preceding vehicle speed measuring unit that measures a vehicle speed of a preceding vehicle traveling in front of the host vehicle, and the vehicle speed measured by the preceding vehicle vehicle speed measuring unit. A vehicle travel control device for controlling acceleration / deceleration of the host vehicle so that the inter-vehicle distance between the host vehicle and the preceding vehicle is substantially the same as a preset inter-vehicle distance. A vehicle speed change calculating means for calculating a degree of change in the vehicle speed measured by the measuring means per specified time, and the degree of change in the vehicle speed per specified time calculated by the vehicle speed change calculating means is larger than a predetermined change degree; When the distance between the vehicle and the preceding vehicle is substantially the same as the set inter-vehicle distance, the travel of the host vehicle is controlled with an acceleration or deceleration that is smaller than the acceleration or deceleration required. .

  According to a second aspect of the present invention, in the vehicle travel control apparatus according to the first aspect, when the degree of change in the vehicle speed per specified time calculated by the vehicle speed change calculating means is larger than a predetermined change degree. The set inter-vehicle distance is extended.

  Further, according to a third aspect of the present invention, in the vehicle travel control device according to the first or second aspect, the set inter-vehicle distance is determined in three types: a long distance, a medium distance, and a short distance. And it has the inter-vehicle distance changing means for the driver to change the set inter-vehicle distance.

  According to the vehicle travel control apparatus of the first aspect of the present invention, when the own vehicle has a greater change in the vehicle speed per prescribed time of the preceding vehicle than the predetermined change, The travel control is performed with an acceleration amount or a deceleration amount that is smaller than an acceleration amount or a deceleration amount necessary to make the inter-vehicle distance substantially equal to the set inter-vehicle distance. Therefore, the degree of change in the vehicle speed of the host vehicle following the preceding vehicle is smaller than that of the preceding vehicle. As a result, the identity of the inter-vehicle distance with the preceding vehicle and the set inter-vehicle distance is reduced, but it is possible to suppress the host vehicle from causing hunting.

  According to the vehicle travel control apparatus of the second aspect of the present invention, the set inter-vehicle distance is extended when the change degree of the vehicle speed per specified time of the preceding vehicle is larger than the predetermined change degree. Thereby, it is possible to suppress a sense of discomfort with respect to the distance to the preceding vehicle that the driver feels due to a change in the inter-vehicle distance with the preceding vehicle that is caused by the preceding vehicle in which the degree of change in the vehicle speed per specified time is larger than the predetermined change degree . This is because, if the degree of change in the vehicle speed of the preceding vehicle is the same, the driver of the own vehicle is suppressed from feeling uncomfortable with respect to the changing distance to the preceding vehicle as the distance from the preceding vehicle increases.

  Furthermore, according to the vehicle travel control apparatus of claim 3, the set inter-vehicle distances are predetermined three types, a long distance, a medium distance, and a short distance, and the driver sets the inter-vehicle distance. The vehicle distance changing means for changing the As a result, the driver can easily change and set the inter-vehicle distance from the preceding vehicle.

  FIG. 1 is referred to as travel control (hereinafter, referred to as “ACC (Adaptive Cruise Control) control”) that substantially maintains an inter-vehicle distance with a preceding vehicle ahead of the host vehicle according to an embodiment of the present invention. The schematic structure of the vehicle W provided with the traveling control apparatus which performs (1) is shown.

  The vehicle W includes a CCD camera that recognizes a preceding vehicle (a vehicle to be maintained at an inter-vehicle distance) traveling in front of the vehicle W as a necessary component of the ACC, that is, as a component of the travel control device 10 of the vehicle W. 12, a radar 14 for measuring the inter-vehicle distance between the vehicle W and the preceding vehicle, a vehicle speed sensor 16 for detecting the vehicle speed of the vehicle W, and an operation unit 18 for setting the inter-vehicle distance provided on the steering wheel, An auto actuator 20 for performing ACC control on the traveling of the vehicle W, a display unit 22 for indicating the inter-vehicle distance to the driver (driver), and a control unit 24 for performing ACC control using these are mounted. .

  The CCD camera 12 is for recognizing a preceding vehicle, and the ACC control of the vehicle W can be performed when the CCD camera 12 images the preceding vehicle. The CCD camera 12 is configured to output a recognition signal to the control unit 24 when the preceding vehicle is imaged and recognized.

  The radar 14 is configured to continue to measure the inter-vehicle distance between the preceding vehicle being imaged by the CCD camera 12 and the vehicle W. The radar 14 is configured to output a signal corresponding to the measured inter-vehicle distance to the control unit 24.

  The vehicle speed sensor 16 detects the vehicle speed of the vehicle W, and is configured to output a signal corresponding to the detected vehicle speed to the control unit 24.

  The operation unit 18 is used when the driver executes the ACC control, and when changing the setting of the inter-vehicle distance with the preceding vehicle during the ACC control. Based on the signal from the operation unit 18, the control unit 24 executes ACC control or changes the ACC control content.

  FIG. 2 shows the operation unit 18. The operation unit 18 is provided on the handle H as shown in FIG. The operation unit 18 has two button switches 30 and 32 as shown in FIG.

  The button switch (button switch described as “ON OFF”) 30 is a switch that is input by a driver when the control unit 24 starts ACC control or stops ACC control being executed.

  On the other hand, a button switch (a button switch described as “DISTANCE”, hereinafter referred to as “inter-vehicle distance change switch”) 32 is input by a driver when changing the inter-vehicle distance set during ACC control. Switch. In the present embodiment, there are three types of inter-vehicle distances (distance values) that can be set: “short distance” (for example, 40 m), “medium distance” (for example, 55 m), and “long distance” (for example, 70 m). Each time the inter-vehicle distance change switch 32 is input, the inter-vehicle distance is sequentially changed to “long distance”, “medium distance”, and “short long distance”. If the inter-vehicle distance change switch 32 is input when the inter-vehicle distance is set to “short distance”, the setting is changed to “long distance”. In this way, since there are three types of inter-vehicle distances that can be set, the driver can easily change the setting of the inter-vehicle distance.

  The auto actuator 20 is configured to control a brake, a throttle, a steering, and the like to execute traveling based on the ACC control based on a control signal from the control unit 24.

  The display unit 22 has a screen incorporated in the instrument panel, and indicates to the driver that the ACC control is being executed and the inter-vehicle distance that has been set during the execution of the ACC. A screen displayed by the display unit 22 is shown in FIG.

  When the inter-vehicle distance is set to “long distance” during the ACC control, the image shown in FIG. 3A is displayed on the display unit 22. A car mark 40a indicating the preceding vehicle is displayed in a small size at the top of the screen, and a comment 42a (LONG) indicating that the current setting is “long distance” is displayed.

  Similarly, during ACC control, when the inter-vehicle distance is set to “medium distance”, the image shown in FIG. 3B is displayed. When the “short distance” is set, FIG. 3C is displayed. The displayed image is displayed on the display unit 22. The preceding vehicle marks 40a to 40c increase in the order of 40a, 40b, and 40c, and the display positions thereof are positioned on the lower side of the screen in the order of 40a, 40b, and 40c.

  In the screen of the display unit 22 (FIGS. 3A to 3C), “100” indicates the vehicle speed of the vehicle W detected by the vehicle speed sensor 16.

  As shown in FIG. 4, the control unit 24 is communicably connected to other components of the travel control device 10.

  The control unit 24 is configured to execute ACC control as follows.

  First, the control unit 24 controls the radar 14 based on the imaging signal of the preceding vehicle from the CCD camera 12 in response to an ACC control start command via the driver operation unit 18, and the radar 14 controls the radar 14 between the preceding vehicle and the vehicle W. Have the vehicle distance measured. Then, a signal corresponding to the inter-vehicle distance is received from the radar 14 and a signal corresponding to the vehicle speed of the vehicle W from the vehicle speed sensor 16 is received.

  Next, the control unit 24 outputs to the auto actuator 20 a control signal that maintains the inter-vehicle distance set by the driver via the operation unit 18 based on signals from the radar 14 and the vehicle speed sensor 16. The auto actuator 20 that has received the control signal controls the traveling of the vehicle W according to the ACC control based on the set inter-vehicle distance. Further, the control unit 24 controls the display unit 22 to display the currently set inter-vehicle distance and the vehicle speed of the vehicle W on the display unit 22.

  The above is the contents of the basic ACC control.

  The basic ACC control described above, that is, the control for maintaining the inter-vehicle distance between the preceding vehicle and the host vehicle W at the inter-vehicle distance set by the driver is substantially the same as the vehicle speed of the preceding vehicle and the vehicle W from a different viewpoint. Therefore, it can be said that the acceleration / deceleration amount of the vehicle W necessary for the calculation is calculated, and the traveling of the vehicle W is controlled based on the calculated acceleration / deceleration amount. Hereinafter, the acceleration / deceleration amount of the vehicle W required to make the vehicle speed of the preceding vehicle substantially the same as the vehicle speed of the vehicle W is referred to as “distance maintaining acceleration / deceleration amount”.

  The basic ACC control described above is good when the vehicle speed of the preceding vehicle is maintained substantially constant, but the vehicle W may cause hunting when the degree of change in the vehicle speed of the preceding vehicle is large.

  Specifically, when the degree of change in the vehicle speed of the preceding vehicle is large, if the control is performed so that the distance between the preceding vehicle and the preceding vehicle is maintained substantially constant (when traveling is controlled by the distance maintaining acceleration / deceleration amount), The degree of change in the vehicle speed is also increased as in the preceding vehicle. Therefore, the vehicle W may cause hunting.

  In this specification, “change in vehicle speed” means that the vehicle accelerates or decelerates in a short time, and the acceleration or deceleration is different or is performed irregularly or periodically with the same acceleration amount (deceleration amount). The change in the vehicle speed when it is Variations in vehicle speed, which will be described later, are also included in “changes in vehicle speed” (in terms of meaning, variations indicate irregular changes).

  As a countermeasure for hunting of the vehicle W, the control unit 24 is configured to be able to execute ACC control having a content different from that of the basic ACC control.

  First, the control unit 24 detects the degree of change in the vehicle speed of the preceding vehicle based on signals from the radar 14 and the vehicle speed sensor 16, in other words, based on the distance between the preceding vehicle and the vehicle speed of the vehicle W. The vehicle speed of the vehicle is calculated. (That is, the control unit 24 functions as the preceding vehicle speed measuring means in the claims).

  In addition, when the degree of change in the vehicle speed per predetermined time specified in advance of the preceding vehicle is larger than the predetermined degree of change (the degree of change in which the vehicle W may cause hunting), the control unit 24 The traveling of the host vehicle W is controlled with an acceleration amount or a deceleration amount that is smaller than an acceleration amount or a deceleration amount necessary to make the inter-vehicle distance substantially the same as the inter-vehicle distance set by the driver.

  Hereinafter, the content of control executed by the control unit 24 will be described in detail by taking as an example the case where the degree of variation in vehicle speed is the degree of change in vehicle speed.

  When the degree of variation in the vehicle speed per specified time of the preceding vehicle is larger than the predetermined variation (the variation in which the vehicle W may cause hunting), the inter-vehicle distance from the preceding vehicle is set by the driver The travel of the host vehicle W is controlled with an acceleration amount or deceleration amount that is smaller than the acceleration amount or deceleration amount required to be substantially the same as the inter-vehicle distance.

  When the degree of variation in the vehicle speed is set as the degree of change in the vehicle speed, the control unit 24 calculates the degree of variation in the vehicle speed of the preceding vehicle per predetermined time (variation value) from the calculated vehicle speed of the preceding vehicle. (The control unit 24 functions as vehicle speed changing means described in the claims). That is, the degree of variation in the vehicle speed of the preceding vehicle is calculated every time the specified time elapses.

  The degree of vehicle speed variation (variation value) will be described with reference to FIG.

FIG. 5 shows the time axis (t). An expression representing the variation value U (tn) of the vehicle speed of the preceding vehicle at a certain time tn is shown in Equation 1.

  In the equation of variation in vehicle speed shown in Equation 1, U (tn-1) represents a variation value calculated before U (tn), and V (tn-2.8) is 2.8 seconds before tn. Vave {tn, (tn−5.6)} indicates the average vehicle speed of the preceding vehicle in a period between tn and time 5.6 seconds before tn. ABS [] indicates an absolute value in parentheses.

  FIG. 6 shows the variation value of the vehicle speed of the preceding vehicle calculated from the equation shown in Equation 1, the vehicle speed of the preceding vehicle, and the average vehicle speed of the preceding vehicle. In FIG. 6, the left vertical axis indicates the vehicle speed of the preceding vehicle, and the right vertical axis indicates the variation value of the vehicle speed of the preceding vehicle.

  For example, as shown in FIG. 6, when the vehicle speed of the preceding vehicle changes between about 49.4 to 50.6 kph, the variation value of the vehicle speed is about 0 to 0.4 kph based on the equation shown in Equation 1. It becomes the value between.

  For example, as shown in FIG. 7, in a vehicle A having a relatively large change (range) in vehicle speed and a vehicle B having a relatively small change in vehicle speed, the degree (range) of vehicle speed variation is It can be seen that is larger than vehicle B.

  As can be seen from FIGS. 6 and 7, the degree of change in vehicle speed corresponds to the degree of variation in vehicle speed.

  The traveling unit 24 calculates the acceleration amount or the deceleration amount of the vehicle W based on the calculated degree of variation in the vehicle speed. Specifically, first, the vehicle speed variation is larger than the predetermined variation (the value calculated using the equation for calculating the variation in Equation 1 is larger than the predetermined value). The distance maintaining acceleration / deceleration amount is obtained so as to be substantially the same as the set inter-vehicle distance. Subsequently, the traveling unit 24 calculates an acceleration / deceleration amount (hereinafter referred to as “execution acceleration / deceleration measurement”) for actually executing the traveling control of the vehicle W, which is smaller than the obtained distance maintaining acceleration / deceleration amount. For example, the effective acceleration / deceleration amount is set to a value 0.5 times the distance maintaining acceleration / deceleration amount.

  Finally, the control unit 24 controls the acceleration / deceleration of the vehicle W with the calculated execution acceleration / deceleration amount.

In summary, when the degree of variation in the vehicle speed of the preceding vehicle is larger than the predetermined variation, the control unit 24 accelerates / decelerates the vehicle W with an effective acceleration / deceleration amount that is smaller than the distance maintaining acceleration / deceleration amount. Control. Thereby, it is suppressed that the vehicle speed of the vehicle W changes similarly to the vehicle speed of the preceding vehicle. As a result, the vehicle W is suppressed from hunting when the vehicle W follows the preceding vehicle.

  Next, an example of a control flow performed by the control unit 24 based on these contents is shown in FIG.

  First, in step 100, a distance maintaining acceleration / deceleration amount is calculated so that the inter-vehicle distance from the preceding vehicle is substantially the same as the set inter-vehicle distance set by the driver.

  Next, in step 110, a variation value of the vehicle speed of the preceding vehicle is calculated based on the vehicle speed of the preceding vehicle.

  Subsequently, in step 120, it is determined whether or not the variation value calculated in step 110 is equal to or less than a predetermined variation value. When the calculated variation value is equal to or less than the predetermined variation value, the process proceeds to step 140. Otherwise, go to step 150.

  In step 140, the effective acceleration / deceleration amount is made the same as the distance maintaining acceleration / deceleration amount, and the process proceeds to step 160.

  In step 150, the effective acceleration / deceleration amount is set to 0.5 times the distance maintaining acceleration / deceleration amount, and the process proceeds to step 160.

  In step 160, the control unit 24 controls the traveling of the vehicle W with the execution acceleration / deceleration amount determined in step 140 or step 150. Then, the control flow ends.

  The flow shown in FIG. 8 is executed every time the variation value of the preceding vehicle is calculated, that is, every time the specified time elapses.

  Although the present invention has been described with reference to one embodiment, the present invention is not limited to this.

  For example, when the change in the vehicle speed per specified time of the preceding vehicle is larger than the predetermined change, the set inter-vehicle distance set by the driver may be extended.

  If the degree of change in vehicle speed of the preceding vehicle that is approximately the same distance as the set inter-vehicle distance set by the driver is large, the distance to the preceding vehicle that the driver changes may be uncomfortable, especially if the set inter-vehicle distance is The shorter the distance, the more uncomfortable. Therefore, when the degree of change in the vehicle speed per specified time of the preceding vehicle is larger than the predetermined change degree, by extending the set inter-vehicle distance set in the driver, that is, by extending the inter-vehicle distance with the preceding vehicle, It is possible to suppress a sense of incongruity with the distance to the preceding vehicle that the driver feels. This is because if the degree of change in the vehicle speed of the preceding vehicle is the same, the driver can be prevented from feeling uncomfortable with respect to the distance to the preceding vehicle that changes as the distance from the preceding vehicle increases.

  As a method for extending the set inter-vehicle distance, for example, in the above-described embodiment, when the set inter-vehicle distance is a short distance, there is a method of changing the setting to a medium distance or a long distance. Alternatively, there is a method of increasing the set inter-vehicle distance when the degree of change in the vehicle speed per specified time of the preceding vehicle is larger than a predetermined change, for example, 1.5 times.

  Further, “change in vehicle speed” is not limited to “variation in vehicle speed” in the above-described embodiment. In a broad sense, the change in the vehicle speed means a change in which a vehicle that follows the preceding vehicle causes hunting when the degree of change in the vehicle speed of the preceding vehicle increases.

  Further, the method of expressing the degree of change in the vehicle speed is not limited to the “variation value” in the above-described embodiment. For example, the degree of change in vehicle speed may be represented by the difference between the average vehicle speed per specified time of the preceding vehicle and the maximum vehicle speed (or minimum vehicle speed) within the specified time, or the deviation of the vehicle speed within the specified time.

1 is a schematic configuration diagram of a vehicle equipped with a travel control device according to an embodiment of the present invention. It is the figure which expanded the operation part of the traveling control apparatus shown in FIG. It is the figure which showed the some example of a display of the display part of the traveling control apparatus shown in FIG. It is a figure which shows the structure of a traveling control apparatus, and the flow of a signal. It is a figure for demonstrating the variation value of the vehicle speed which shows the grade of the change of a vehicle speed. It is a graph which shows the relationship between the vehicle speed, the average vehicle speed, and the variation value of a vehicle speed in a preceding vehicle. It is a graph which shows the dispersion | variation in the vehicle speed and vehicle speed in two preceding vehicles from which the grade of the change of a vehicle speed differs. It is a figure of the control flow for changing the amount of acceleration / deceleration of the vehicle which follows the preceding vehicle according to the degree of change of the vehicle speed of the preceding vehicle.

Claims (3)

The vehicle has a preceding vehicle speed measuring means for measuring the vehicle speed of the preceding vehicle traveling in front of the own vehicle, and the inter-vehicle distance between the own vehicle and the preceding vehicle is preset based on the vehicle speed measured by the preceding vehicle speed measuring means. A vehicle travel control device that performs acceleration / deceleration control of the host vehicle so as to be substantially the same as the set inter-vehicle distance,
Vehicle speed change calculating means for calculating the degree of change per prescribed time of the vehicle speed measured by the preceding vehicle vehicle speed measuring means;
Acceleration amount necessary to make the inter-vehicle distance from the preceding vehicle substantially the same as the set inter-vehicle distance when the change in the vehicle speed per prescribed time calculated by the vehicle speed change calculating means is larger than the predetermined change Alternatively, the vehicle travel control apparatus controls the travel of the host vehicle with an acceleration amount or a deceleration amount that is smaller than the deceleration amount. The vehicle travel control apparatus according to claim 1,
A travel control device for a vehicle, wherein the set inter-vehicle distance is extended when a change in the vehicle speed per specified time calculated by the vehicle speed change calculating means is larger than a predetermined change. In the vehicle travel control device according to claim 1 or 2,
There are three types of inter-vehicle distances that are determined in advance: long distance, medium distance, and short distance,
A travel control device for a vehicle, characterized in that a driver has a vehicle-to-vehicle distance changing means for changing a set vehicle-to-vehicle distance.

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