JP5054389B2 - Vehicle driving support device - Google Patents

Description

  The present invention relates to a driving support apparatus for a vehicle that performs acceleration / deceleration control following a preceding vehicle.

  2. Description of the Related Art In recent years, in vehicles, various vehicle driving support devices that recognize a preceding vehicle using a front recognition device using a camera, a laser radar, and the like and follow the recognized preceding vehicle have been developed and put into practical use.

For example, in Japanese Laid-Open Patent Publication No. 2000-355231, in a preceding vehicle follow-up control device that matches the own vehicle speed with the target vehicle speed calculated based on the inter-vehicle distance and the own vehicle speed, a large value is obtained when the own vehicle speed is in the low vehicle speed region. Thus, the lateral acceleration correction value is calculated by subtracting the offset amount, which is a small value in the high vehicle speed region, from the lateral acceleration detected by the lateral acceleration sensor. Based on this lateral acceleration correction value, a vehicle speed subtraction value that is small when it is small and large when it is large is calculated, and the target vehicle speed is suppressed based on this vehicle speed subtraction value. A technique for eliminating the uncomfortable feeling given to the driver by optimally performing the deceleration control is disclosed.
JP 2000-355231 A

  However, in the technology for suppressing the target vehicle speed disclosed in Patent Document 1 described above, since the target vehicle speed is suppressed based on the current vehicle behavior, acceleration / deceleration after the actual vehicle behavior occurs is suppressed. However, there is a problem that a delay occurs with respect to the actual feeling and the vehicle behavior deviates from the movement of the preceding vehicle to follow, and the driver has an unnatural feeling.

  The present invention has been made in view of the above circumstances, considering not only the current vehicle behavior but also the vehicle behavior expected in the future, from the straight running state to the curve running, for example, the transient state of these running paths. It is an object of the present invention to provide a vehicle driving support apparatus that can appropriately suppress the acceleration / deceleration of a vehicle and can perform smooth and comfortable control when following a preceding vehicle.

The present invention includes a host vehicle travel information detection unit that detects travel information of the host vehicle, a preceding vehicle information detection unit that recognizes a preceding vehicle and detects the preceding vehicle information, the traveling information of the host vehicle, and the preceding vehicle. Based on the information, the target acceleration / deceleration calculating means for calculating the target acceleration / deceleration necessary for the host vehicle to follow the preceding vehicle, and the host vehicle based on the host vehicle travel information and the preceding vehicle information. A target parameter necessary for the vehicle to follow the preceding vehicle is estimated, a first limit value for limiting the target acceleration / deceleration calculated according to the target parameter, and a change amount of the target parameter per unit time And a third limit value for limiting the target acceleration / deceleration calculated according to the difference between the target parameter and the current actual parameter value. Less By one of the limit values with, and a target acceleration limiting means for limiting the target acceleration, the target acceleration limiting means, said first limit value and the second limit value and the third restriction When the target acceleration / deceleration is limited by any two limit values or by these three limit values, the target acceleration / deceleration is limited by using the limit value having the smallest absolute value among the plurality of limit values. It is characterized in that.

  According to the vehicle driving support device of the present invention, considering not only the current vehicle behavior but also the vehicle behavior expected in the future, from the straight traveling state to the curve traveling, even in the transient state of these traveling paths. Even in the driving situation, the acceleration / deceleration of the vehicle is appropriately suppressed, and smooth and comfortable control can be performed when following the preceding vehicle.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 10 show an embodiment of the present invention, FIG. 1 is a schematic configuration diagram of a driving support device mounted on a vehicle, FIG. 2 is a flowchart of a follow-up acceleration / deceleration control program, and FIG. 3 is a target acceleration / deceleration a calculation process. 4 is a flowchart of a target acceleration / deceleration a restriction processing routine, FIG. 5 is an explanatory diagram of an area map of a target vehicle acceleration / deceleration-preceding vehicle speed target acceleration / deceleration equation, and FIG. 6 is used in a target acceleration / deceleration equation. FIG. 7 is an explanatory diagram showing the relationship between the coordinate positions of the host vehicle and the preceding vehicle, FIG. 8 is an explanatory diagram showing an example of the limit value, and FIG. 9 is an explanatory diagram of an example of shifting from a straight path to a curve run FIG. 10 is a time chart showing an example of limit values set when traveling on the travel path shown in FIG.

  In FIG. 1, reference numeral 1 denotes a vehicle such as an automobile (own vehicle), and a cruise control system (ACC (Adaptive Cruise Control) system) 2 as an example of a driving support device is mounted on the vehicle 1.

  The ACC system 2 mainly includes a stereo camera 3, a stereo image recognition device 4, a control unit 5, and the like. In the ACC system 2, basically, the vehicle travels while maintaining the vehicle speed set by the driver in the constant speed traveling control state in which no preceding vehicle exists, and the following acceleration / deceleration control in the case where the preceding vehicle exists. The automatic tracking control of the tracking steering control is executed.

  Further, the host vehicle 1 is provided with a vehicle speed sensor 6 that detects the host vehicle speed V0, a steering wheel angle sensor 7 that detects the steering angle Sr, and a yaw rate sensor 8 that detects the yaw rate γr. The vehicle speed V0 is input to the stereo image recognition device 4 and the control unit 5, and the steering angle Sr and the yaw rate γr are input to the control unit 5. Further, an ON-OFF signal of a brake pedal from a brake switch (not shown) is input to the control unit 5.

  In addition, signals from various switches from a constant speed travel switch 9 constituted by a plurality of switches connected to a constant speed travel operation lever provided on the side of the steering column or the like are input to the control unit 5. The constant speed travel switch 9 is a vehicle speed set switch that sets a target vehicle speed during constant speed travel, a coast switch that mainly changes and sets the target vehicle speed to the lower side, a resume switch that mainly changes and sets the target vehicle speed to the higher side, etc. It consists of Further, a main switch (not shown) for turning ON / OFF constant speed traveling control and automatic tracking control is disposed in the vicinity of the constant speed traveling operation lever.

  The stereo camera 3 is composed of a set of (left and right) CCD cameras using a solid-state imaging device such as a charge coupled device (CCD) as a stereo optical system. These left and right CCD cameras are each mounted at a certain interval in front of the ceiling in the vehicle interior, take a stereo image of an object outside the vehicle from different viewpoints, and output image data to the stereo image recognition device 4.

  The stereo image recognition device 4 receives the image data from the stereo camera 3 and the own vehicle speed V0 from the vehicle speed sensor 6, and based on the image data from the stereo camera 3, the front information of the three-dimensional object data and the white line data in front of the own vehicle 1. Is detected, and the traveling path of the own vehicle 1 (own vehicle traveling path) is estimated. Then, the preceding vehicle ahead of the host vehicle 1 is extracted, and the preceding vehicle position (for example, the coordinate position on the XZ coordinate system with the host vehicle 1 as the origin as shown in FIG. 7), the preceding vehicle distance (inter-vehicle distance). Distance) L, preceding vehicle speed ((change in inter-vehicle distance L) + (own vehicle speed V0)) Vf, preceding vehicle acceleration / deceleration (differential value of preceding vehicle speed Vf) af, position of stationary object other than preceding vehicle, white line coordinates, white line Each data such as the recognition distance and the own vehicle traveling path coordinates is output to the control unit 5.

  Here, the processing of the image data from the stereo camera 3 in the stereo image recognition device 4 is performed as follows, for example. First, for a pair of stereo images of the environment in the traveling direction of the host vehicle 1 imaged by the CCD camera of the stereo camera 3, a process for obtaining distance information by the principle of triangulation from the corresponding positional deviation amount is performed. A distance image representing a three-dimensional distance distribution is generated. And based on this data, compared with well-known grouping processing and pre-stored three-dimensional road shape data, solid object data, etc., white line data, guardrails, curbs, etc. existing along the road Side wall data and three-dimensional object data such as vehicles are extracted.

  In the three-dimensional object data, the distance to the three-dimensional object and the temporal change (relative speed with respect to the own vehicle 1) of this distance are obtained. In particular, in the closest vehicle on the own vehicle traveling path, in the same direction as the own vehicle 1 A vehicle traveling at a predetermined speed (for example, 0 km / h or more) is extracted as a preceding vehicle. Of the preceding vehicles, a vehicle having a speed Vf of approximately 0 km / h is recognized as a stopped preceding vehicle. Further, as the three-dimensional object information and the preceding vehicle information, the position information of the left end point and the right end point of the rear surface is stored, and the approximate center between the left end point and the right end point of the rear surface is the center of gravity position of the three-dimensional object or the preceding vehicle. Is remembered as Thus, the stereo camera 3 and the stereo image recognition device 4 have a function as a preceding vehicle information detection means.

  The control unit 5 includes a function of constant speed traveling control for performing constant speed traveling control so as to maintain a traveling speed set by a driver's operation input, and automatic tracking control (tracking acceleration / deceleration control and tracking steering control). When the driver turns on a main switch (not shown) and sets a desired vehicle speed with a constant speed operation lever, a signal from the constant speed travel switch 9 is input to the control unit 5. Then, a signal is output to the throttle valve control device 10 so that the vehicle speed detected by the vehicle speed sensor 6 converges to the set vehicle speed set by the driver, and the opening degree of the throttle valve 11 is feedback-controlled, so that the host vehicle 1 is automatically operated. The vehicle is run at a constant speed, or a deceleration signal is output to the automatic brake control device 12 to activate the automatic brake.

  When the stereo image recognition device 4 recognizes the preceding vehicle during the constant speed traveling control, the control unit 5 is automatically switched to automatic follow-up control described later. Note that the constant speed traveling control function and the automatic tracking control function are canceled when the driver steps on the brake or when the main switch is turned off.

  When the vehicle travel control shifts to the follow-up travel control, in the example of the follow-up acceleration / deceleration control of the present embodiment, the target vehicle acceleration / deceleration af−the preceding vehicle speed Vf composed of two preset areas will be described in detail later. Referring to the area map of the acceleration / deceleration calculation formula, select the target acceleration / deceleration calculation formula for the area to which the current acceleration / deceleration af and speed Vf belong, and calculate the target acceleration / deceleration a using the selected target acceleration / deceleration calculation formula To do.

  Further, a target yaw rate γt as a target parameter necessary for the host vehicle 1 to follow the preceding vehicle is calculated based on the host vehicle speed V0 and the relative position of the preceding vehicle with respect to the host vehicle 1.

  Further, a limit value (first limit value Lmγ1) is calculated according to the target yaw rate γt, and a limit value (second limit value) according to the amount of change (γt−γtold) / Δt of the target yaw rate γt per unit time. Lmγ2) is calculated, a limit value (third limit value Lmγ3) is calculated according to a deviation Δγ (= γt−γr) between the target yaw rate γt and the current actual yaw rate γr, and the first, second, The smallest absolute value of the third limit value is set as the limit value Lm.

  Then, the target acceleration / deceleration a is limited by the limit value Lm, and a signal is output to the automatic brake control device 12 to perform automatic brake control (including follow-up stop control), or a signal is output to the throttle valve control device 10. Performs automatic acceleration control (including tracking start control). As described above, in the present embodiment, the control unit 5 is configured to have functions as a target acceleration / deceleration calculating means and a target acceleration / deceleration limiting means.

  In addition, when the vehicle traveling control shifts to the tracking traveling control, the control unit 5 executes the vehicle speed V0 in an area where the vehicle speed V0 is, for example, less than 35 km / h in the example of the tracking steering control of the present embodiment. In the case of the vehicle speed region set in advance in the vehicle, the target yaw rate γt required for the own vehicle 1 to follow the preceding vehicle is calculated based on the own vehicle speed V0 and the relative position of the preceding vehicle with respect to the own vehicle 1. Based on this target yaw rate γt, the power steering command current value ic that follows the preceding vehicle is calculated and output to the electric power steering control device 13. On the other hand, in the vehicle speed region set in advance in the vehicle speed region, the target steering angle St required for the host vehicle 1 to follow the preceding vehicle based on the relative position of the preceding vehicle with respect to the host vehicle 1 is set. Based on this target steering angle St, the power steering command current value ic that follows the preceding vehicle is calculated and output to the electric power steering control device 13.

  Reference numeral 14 denotes a liquid crystal monitor that displays each operating state of the ACC system 2, and is shared with, for example, an in-vehicle navigation system.

  Next, follow-up acceleration / deceleration control of follow-up running control will be described with reference to the flowchart of FIG. This follow-up acceleration / deceleration control program is executed every predetermined time when the main switch of the ACC system 2 is turned on and shifts to follow-up running control in which a preceding vehicle is present. First, a step (hereinafter, “S”) is executed. (Abbreviated as) 101, necessary parameters are read. Next, the process proceeds to S102, where the target acceleration / deceleration a calculation process is executed, and the process proceeds to S103, where the target acceleration / deceleration a calculated in S102 is limited, and the process proceeds to S104, where it is limited as necessary in S103. The processed target acceleration / deceleration a is output to the automatic brake control device 12 or the throttle valve control device 10 to exit the program.

  Here, first, the calculation process of the target acceleration / deceleration a executed in S102 will be described with reference to the flowchart of FIG.

  First, in S201, the arithmetic expression selection flag Fa is referred to. This calculation formula selection flag Fa is set to “1” when the first calculation formula described later is selected last time according to the traveling state (acceleration / deceleration af, vehicle speed Vf) of the preceding vehicle, and is set to “2” described later. This flag is set when “2” is selected.

  Here, in the present embodiment, the area map of the target vehicle acceleration / deceleration formula of preceding vehicle acceleration / deceleration af−preceding vehicle speed Vf composed of two regions set in advance, and the calculation equation (first An arithmetic expression and a second arithmetic expression) will be described.

  The area of the target vehicle acceleration / deceleration af-preceding vehicle speed Vf target acceleration / deceleration equation is, for example, as shown in FIG. 5A, the absolute value | af | of the preceding vehicle and the absolute value | Vf of the preceding vehicle. |, Vf = 1.0 · af is the boundary line Tth, and the upper region (region where the absolute value | Vf | of the preceding vehicle is high but the absolute value | af | of the acceleration / deceleration is small) is the first region. The second region is set as the first region for selecting the arithmetic expression 1 and the lower region (region where the absolute value | Vf | of the preceding vehicle is low but the absolute value | af | of the acceleration / deceleration is high) is the second region. It is preset as a second area for selecting an expression. In this embodiment, the sign of acceleration / deceleration is positive in the deceleration direction and negative in the acceleration direction.

The first arithmetic expression is an arithmetic expression for following the vehicle while maintaining the inter-vehicle distance set in advance by the host vehicle 1 with respect to the preceding vehicle on the assumption that the preceding vehicle continues to travel. 1 and the preceding vehicle are in a relationship as shown in FIG. 6, that is, the current vehicle speed V0, the own vehicle acceleration / deceleration a0, the preceding vehicle speed Vf, the preceding vehicle acceleration / deceleration af, and the inter-vehicle distance L after t seconds. If the host vehicle 1 moves forward by a distance Ls, the preceding vehicle moves forward by a distance Lf to the preceding vehicle predicted position, and the inter-vehicle distance from the host vehicle 1 becomes a target inter-vehicle distance Dtgt (a distance set by a map or calculation), The target acceleration / deceleration a of the vehicle 1 is obtained from the following equation (1).
a = af + ((V0−Vf) ² / (L−Dtgt)) (1)
Therefore, the expression (1) is defined as the first arithmetic expression in the first region.

Similarly, the second arithmetic expression is an arithmetic expression for the vehicle 1 to follow and stop the preceding vehicle at a preset inter-vehicle distance on the assumption that the preceding vehicle stops. As shown in FIG. In other words, the current vehicle speed V0, the own vehicle acceleration / deceleration a0, the preceding vehicle speed Vf, the preceding vehicle acceleration / deceleration af, and the inter-vehicle distance L, the host vehicle 1 moves forward by the distance Ls after t seconds, and the preceding vehicle If the vehicle travels a distance Lf up to the predicted position of the preceding vehicle and the distance between the vehicle 1 and the host vehicle 1 becomes the target stop distance Dstop (constant value: 5 m, for example), the following equation (2) is established.
L + Lf = Ls + Dstop (2)
here,
Lf = Vf ² / (2 · af) (3)
Ls = V0 ² / (2 · a0) (4)
Therefore, substituting these equations (3) and (4) into the above equation (2), solving for a0, and setting this a0 as the target acceleration / deceleration a of the host vehicle 1, the following equation (5) Get.

a = (af · V0 ² ) / (Vf ² + 2 · af · (L−Dstop)) (5)
Therefore, this equation (5) is defined as the second arithmetic expression in the second region. Note that the sign of the deceleration direction is positive for all the accelerations and decelerations described above.

  It should be noted that the area map of the target acceleration / deceleration equation of the preceding vehicle acceleration / deceleration af−preceding vehicle speed Vf composed of the above-described two areas is not limited to this, and may be divided by a plurality of boundaries. good.

  As a result of the determination in S201 of the flowchart of FIG. 3, if the arithmetic expression selection flag Fa is “1” and the first arithmetic expression has been selected last time, the process proceeds to S202, and the first area is changed to the first area. In order to provide a hysteresis characteristic when transitioning to the region 2, correction is set by moving the boundary Tth downward by S1 so as to widen the first region. For example, the correction is made as shown in FIG.

  On the other hand, as a result of the determination in S201, if the arithmetic expression selection flag Fa is “2” and the second arithmetic expression has been selected last time, the process proceeds to S203, and the first area is selected from the second area. In order to give a hysteresis characteristic when transitioning to a region, the boundary Tth is moved upward by S2 so as to widen the second region, and correction is set. For example, the correction is made as shown in FIG. Here, the width for providing the hysteresis is S1> S2, and the transition from the first arithmetic expression to the second arithmetic expression is more effective than the transition from the second arithmetic expression to the first arithmetic expression. It is set to difficult characteristics.

  After performing region correction in consideration of hysteresis in S202 or S203, the process proceeds to S204 to determine whether or not the current traveling state of the preceding vehicle (preceding vehicle acceleration / deceleration af−preceding vehicle speed Vf) is within the first region. To do.

  As a result of the determination in S204, if the current traveling state of the preceding vehicle (preceding vehicle acceleration / deceleration af−preceding vehicle speed Vf) is within the first region, the process proceeds to S205 and the first arithmetic expression (the above-described (1) The target acceleration / deceleration a is calculated from the equation (1), the process proceeds to S206, the calculation equation selection flag Fa is set to "1", and the routine is exited.

  If the current traveling state of the preceding vehicle (preceding vehicle acceleration / deceleration af−preceding vehicle speed Vf) is within the second region as a result of the determination in S204, the process proceeds to S207, and the second arithmetic expression ((5 )), The target acceleration / deceleration a is calculated, the process proceeds to S208, the calculation expression selection flag Fa is set to "2", and the routine is exited.

  As described above, according to the embodiment of the present invention, the following traveling control (following acceleration / deceleration control) is performed by switching the expression for following traveling according to the traveling state of the preceding vehicle. It is performed continuously and the driver can use the driver with a natural feeling through smooth control. In addition, since the boundary line is set in consideration of hysteresis, the control can be performed stably without hunting.

  Next, the target acceleration / deceleration speed limiting process executed in S103 will be described with reference to the flowchart of FIG.

First, in S301, a predicted time (contact predicted time) TTC until the host vehicle 1 reaches the preceding vehicle is calculated by, for example, the following equation (6).
TTC = L / (V0−Vf) (6)

  Thereafter, the process proceeds to S302, in which it is determined whether or not the predicted contact time TTC calculated in S301 is shorter than a preset time TT1 (for example, 5 seconds), and when it is shorter than TT1 (when TTC <TT1), Prioritizing safety, the target acceleration / deceleration a is not limited, and the routine is exited as it is.

Conversely, when the predicted contact time TTC is equal to or longer than the preset time TT1 (when TTC ≧ TT1), the process proceeds to S303, and the current position of the host vehicle 1 and the preceding position are calculated by the following equation (7). A target travel radius Rt is calculated based on the position of the car. That is, in the coordinate system shown in FIG. 7 where the host vehicle 1 is the origin O, the coordinates of the center of gravity position of the preceding vehicle are (xt, zt).
Rt = (xt ² + zt ² ) / (2 · xt) (7)

Next, the process proceeds to S304, and the target yaw rate γt is calculated by the following equation (8).
γt = V0 / Rt (8)

After calculating the target yaw rate γt in S304, the process proceeds to S305, and the first limit value Lmγ1 is calculated based on the target yaw rate γt by the following equation (9).
| Lmγ1 | = Lmc1−K1 · | γt | (9)
Here, the reason why Lmγ1 is an absolute value is to apply the formula (9) in both the acceleration direction and the deceleration direction. K1 is a constant, and Lmc1 is a constant (for example, 0.5 · g). When the first limit value | Lmγ1 | calculated by the equation (9) is | Lmγ1 |> Lmc2 (for example, 0.3 · g), | Lmγ1 | is limited by Lmc2 (| Lmγ1 | = Lmc2 ) The characteristic of the limit value Lmγ1 is shown in FIG. In the present embodiment, the limit value Lmγ1 in the acceleration direction and the deceleration direction has the same characteristic, but may have different characteristics.

  Next, in S306, the amount of change (γt−γtold) / Δt per unit time of the target yaw rate γt is calculated. Here, Δt is a unit time (for example, the time from the previous time to the current time), and γtold is a target yaw rate before the unit time Δt (for example, the previous time).

After calculating the change amount (γt−γtold) / Δt of the target yaw rate γt in S306, the process proceeds to S307, and the change amount (γt per unit time of the target yaw rate γt is calculated by the following equation (10). The second limit value Lmγ2 is calculated based on −γtold) / Δt.
| Lmγ2 | = Lmc3−K2 · | (γt−γtold) / Δt | (10)
Here, the reason why Lmγ2 is an absolute value is to apply this equation (10) in both the acceleration direction and the deceleration direction. K2 is a constant, and Lmc3 is a constant (for example, 0.5 · g). If the second limit value | Lmγ2 | calculated by the equation (10) is | Lmγ2 |> Lmc4 (for example, 0.3 · g), | Lmγ2 | is limited by Lmc4 (| Lmγ2 | = Lmc4 ) The characteristic of the second limit value Lmγ2 is shown by replacing γt with (γt−γtold) / Δt, Lmγ1 with Lmγ2, Lmc1 with Lmc3, and Lmc2 with Lmc4 in the characteristic diagram of Lmγ1 in FIG. . In the present embodiment, the second limit value Lmγ2 in the acceleration direction and the deceleration direction has the same characteristic, but may have different characteristics.

  Next, in S308, a deviation (yaw rate deviation) Δγ (= γt−γr) between the target yaw rate γt and the current actual yaw rate γr is calculated.

Next, in S309, the third limit value Lmγ3 is calculated based on the yaw rate deviation Δγ according to the following equation (11).
| Lmγ3 | = Lmc5−K3 · | Δγ | (11)
Here, the reason why Lmγ3 is set to an absolute value is to apply this equation (11) in both the acceleration direction and the deceleration direction. K3 is a constant, and Lmc5 is a constant (for example, 0.5 · g). When the third limit value | Lmγ3 | calculated by the expression (11) is | Lmγ3 |> Lmc6 (for example, 0.3 · g), | Lmγ3 | is limited by Lmc6 (| Lmγ3 | = Lmc6). ) The characteristic of the third limit value Lmγ3 is shown by replacing γt with Δγ, Lmγ1 with Lmγ3, Lmc1 with Lmc5, and Lmc2 with Lmc6 in the characteristic diagram of Lmγ1 in FIG. In the present embodiment, the third limit value Lmγ3 in the acceleration direction and the deceleration direction has the same characteristics, but may have different characteristics.

  Next, the process proceeds to S310, the smallest absolute value of the first, second, and third limit values is set to the limit value Lm. The process proceeds to S311 and the target acceleration / deceleration a calculated in S102 is set to the limit value Lm. When the absolute value | a | of the target acceleration / deceleration is equal to or larger than the absolute value | Lm | of the limit value, the absolute value | a | of the target acceleration / deceleration is limited as the absolute value | Lm | , Exit the routine.

  That is, for example, as shown in FIG. 9, when the vehicle moves from a straight path to a curve, the target yaw rate γt is substantially 0 in the situation where the preceding vehicle has reached the curve as shown in FIG. Yes, the absolute value | Lmγ1 | of the first limit value calculated at this time takes a large value. Further, as shown in FIG. 10C, the yaw rate deviation Δγ also remains small in the situation where the preceding vehicle has reached the curve, and the absolute value | Lmγ3 | of the third limit value is still a large value. Take. In such a situation, as shown in FIG. 10 (b), the absolute value | (γt−γtold) / Δt | of the change amount per unit time of the target yaw rate γt changes most greatly according to the behavior of the preceding vehicle. Thus, the absolute value | Lmγ2 | of the second limit value can be reduced. Then, the smallest absolute value of the first, second and third limit values is set as the limit value Lm, and the absolute value | Lmγ2 | of the second limit value is set as the limit value Lm (FIG. 10). (See (c)), the follow-up control at the time of transition from the straight road to the curve travel is made smooth, and comfortable control without a sense of incongruity can be performed. Further, in the case where, for example, a plurality of curves are continuous other than the case where the vehicle travels from the straight road to the curve, the minimum absolute value of the first, second and third limit values is similarly set. By setting the limit value Lm and limiting the absolute value a of the target acceleration / deceleration with the limit value Lm, from the straight traveling state to the curve traveling, even in the traveling state in the transient state of these traveling paths, The acceleration / deceleration is appropriately suppressed, and smooth and comfortable control can be performed when following the preceding vehicle.

  Further, the target yaw rate γt used when calculating the first, second, and third limit values is determined so that the own vehicle 1 follows the preceding vehicle based on the own vehicle speed V0 and the relative position of the preceding vehicle with respect to the own vehicle 1. Therefore, the acceleration / deceleration of the vehicle is appropriately suppressed in consideration of not only the current vehicle behavior but also the expected vehicle behavior in the future. Comfortable control without discomfort is possible.

  Further, the calculation of the limit value Lm in the present embodiment is performed by a simple linear function as in the formulas (9), (10), and (11), so that a complicated algorithm is not required and high speed is achieved. The control with excellent response is possible.

  In the present embodiment, the limit value Lm is set using the first, second, and third limit values, or depending on the vehicle, either the first, second, or third is set. The limit value Lm may be set using only one limit value, or the limit value Lm may be set using any one of the first, second, and third limit values.

  In the present embodiment, the target yaw rate γt is used as the target parameter. However, in addition to the target yaw rate γt, the target steering angle St (= (Lw · Ns) / Rt: Lw is the wheel base, and Ns is the steering. Gear ratio) or target curvature ρt (= 1 / γt) may be used.

  When the target steering angle St is used as the target parameter, the first, second, and third limit values Lms1, Lms2, and Lms3 corresponding to the above formulas (9), (10), and (11) are as follows. (12), (13), and (14).

| Lms1 | = Lmc11−K11 · | St | (12)
| Lms2 | = Lmc13−K12 · | (St−Stold) / Δt | (13)
| Lms3 | = Lmc15−K13 · | ΔS | (14)
Here, Stold is a target steering angle before unit time Δt (for example, last time), ΔS is a deviation (steering angle deviation) (= St−Sr) between target steering angle St and the current actual steering angle Sr, K11, K12 and K13 are constants, and Lmc11, Lmc13, and Lmc15 are constants such as 0.5 · g, for example. Similarly to the above-described equations (9), (10), and (11), the first limit value | Lms1 | calculated by the equation (12) is | Lms1 |> Lmc12 (for example, 0.3 In the case of g), | Lms1 | is limited by Lmc12 (| Lms1 | = Lmc12), and the second limit value | Lms2 | calculated by the equation (13) is | Lms2 |> Lmc14 (for example, 0. 3 · g), | Lms2 | is limited by Lmc14 (| Lms2 | = Lmc14), and the third limit value | Lms3 | calculated by the equation (14) is | Lms3 |> Lmc16 (for example, 0 .3 · g), | Lms3 | is limited by Lmc16 (| Lms3 | = Lmc16).

  When the target curvature ρt is used as the target parameter, the first, second, and third limit values Lmρ1, Lmρ2, and Lmρ3 corresponding to the equations (9), (10), and (11) are respectively Calculation is performed by the following equations (15), (16), and (17).

| Lmρ1 | = Lmc21−K21 · | ρt | (15)
| Lmρ2 | = Lmc23−K22 · | (ρt−ρtold) / Δt | (16)
| Lmρ3 | = Lmc25−K23 · | Δρ | (17)
Here, ρtold is the target curvature before the unit time Δt (for example, the previous time), Δρ is the deviation (curvature deviation) between the target curvature ρt and the current actual curvature (= ρt−ρ), and K21, K22, and K23 are constants. , Lmc21, Lmc23, and Lmc25 are constants such as 0.5 · g, for example. Similarly to the above-described equations (9), (10), and (11), the first limit value | Lmρ1 | calculated by the equation (15) is | Lmρ1 |> Lmc22 (for example, 0.3 In the case of g), | Lmρ1 | is limited by Lmc22 (| Lmρ1 | = Lmc22), and the second limit value | Lmρ2 | calculated by the equation (16) is | Lmρ2 |> Lmc24 (for example, 0. 3 · g), | Lmρ2 | is limited by Lmc24 (| Lmρ2 | = Lmc24), and the third limit value | Lmρ3 | calculated by Equation (17) is | Lmρ3 |> Lmc26 (for example, 0 .3 · g), | Lmρ3 | is limited by Lmc26 (| Lmρ3 | = Lmc26).

  Further, in the present embodiment, the target acceleration / deceleration a is calculated by selecting an arithmetic expression from the area map of the target acceleration / deceleration calculation expression of preceding vehicle acceleration / deceleration af−preceding vehicle speed Vf, which consists of two preset areas. However, it goes without saying that the present invention can be applied even if it is obtained by other methods. For example, the target inter-vehicle time is calculated and set based on the own vehicle speed V0, and the target acceleration / deceleration a is calculated based on the inter-vehicle distance L, the preceding vehicle speed Vf, the own vehicle speed V0, and the target inter-vehicle time. it can.

  In the present embodiment, the preceding vehicle is recognized based on the image from the stereo camera. However, other technologies, for example, those that recognize based on information from the millimeter wave radar and the monocular camera are used. It may be.

Schematic configuration diagram of a driving support device mounted on a vehicle Flow chart of following acceleration / deceleration control program Flow chart of target acceleration / deceleration a calculation processing routine Flow chart of target acceleration / deceleration a limit processing routine Explanatory diagram of the area map of the target vehicle acceleration / deceleration formula for the preceding vehicle acceleration / deceleration-preceding vehicle speed Explanatory diagram of parameters used in the target acceleration / deceleration formula Explanatory diagram showing the relationship between the coordinate position of the host vehicle and the preceding vehicle Explanatory drawing showing an example of the limit value An explanatory diagram of an example of transition from a straight road to a curve run FIG. 9 is a time chart showing an example of limit values set when traveling on the travel path shown in FIG.

Explanation of symbols

1 Vehicle 2 ACC system (driving support device)
3 Stereo camera (preceding vehicle information detection means)
4 Stereo image recognition device (preceding vehicle information detection means)
5 Control unit (target acceleration / deceleration calculation means, target acceleration / deceleration limit means)
6 Vehicle speed sensor (own vehicle travel information detection means)
10 Throttle valve control device 11 Throttle valve 12 Automatic brake control device

Claims (3)

Own vehicle running information detecting means for detecting running information of the own vehicle;
A preceding vehicle information detecting means for recognizing the preceding vehicle and detecting the preceding vehicle information;
Target acceleration / deceleration calculating means for calculating a target acceleration / deceleration necessary for the host vehicle to follow the preceding vehicle based on the traveling information of the host vehicle and the preceding vehicle information;
Based on the travel information of the host vehicle and the preceding vehicle information, a target parameter necessary for the host vehicle to follow the preceding vehicle is estimated, and the target acceleration / deceleration calculated according to the target parameter is limited. The difference between the limit value of 1 and the second limit value for limiting the target acceleration / deceleration calculated according to the change amount per unit time of the target parameter, and the value of the target parameter and the current actual parameter by at least one limit value of the third limit value for limiting the target acceleration which is calculated in accordance with, and a target acceleration limiting means for limiting the target acceleration,
The target acceleration / deceleration limiting means limits the target acceleration / deceleration by any two of the first limit value, the second limit value, and the third limit value, or by these three limit values. In this case, the vehicle driving support apparatus limits the target acceleration / deceleration using a limit value having the smallest absolute value among the plurality of limit values . 2. The vehicle according to claim 1 , wherein the target parameter is at least one of a target yaw rate, a target steering angle, and a target curvature of the host vehicle calculated based on the traveling information of the host vehicle and the preceding vehicle information. Driving assistance device. The target acceleration / deceleration limiting means does not limit the target acceleration / deceleration when the predicted time until the host vehicle reaches the preceding vehicle is shorter than a preset value. The driving support device for a vehicle according to claim 1 or 2.

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