JP2007176290A - Driving support device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving support device of a vehicle capable of achieving following steering control without giving rise to a sense of incongruity even when a preceding vehicle changes due to interruption and departure of a vehicle. <P>SOLUTION: A control unit 5 computes a controlling target value in accordance with a position of the preceding vehicle and a position of the self vehicle 1 and temporarily reduce control gain of feed-back control when a change of the preceding vehicle is determined by a stereo picture image recognition device 4 in the following steering control to compute a steering controlled variable by the feed-back control in accordance with the controlling target value. Consequently, it is possible to achieve the following steering control without the sense of incongruity even when the preceding vehicle changes due to interruption and departure of the vehicle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a driving support device mounted on a vehicle that calculates a steering control amount based on detected preceding vehicle information and performs follow-up traveling with respect to the preceding vehicle.

  In recent years, the front running environment is detected by a camera, etc., and a preceding vehicle is detected from this running environment data, and follow-up steering control for the preceding vehicle, acceleration / deceleration control for keeping the distance between the preceding vehicle and the like above a certain level, etc. A traveling control device has been developed and put into practical use.

  In this type of driving support device, the follow-up steering control with respect to the preceding vehicle obtains a control target value such as a target course based on the position of the preceding vehicle and the position of the host vehicle, as disclosed in Patent Document 1, for example. This can be realized by calculating the steering control amount by PID control or the like based on the control target value.

Here, in the driving support device, generally, the vehicle closest to the own vehicle is detected as the preceding vehicle on the preceding vehicle determination area such as the own vehicle traveling lane set based on the traveling environment data or the like, In the case where another vehicle has entered before the preceding vehicle in the preceding vehicle determination area, or when the preceding vehicle has left the preceding vehicle determination area, the preceding vehicle is appropriately switched. Then, by appropriately switching the preceding vehicle to be controlled as described above, the driving support device can realize continuous follow-up steering control corresponding to the interruption or separation of the vehicle.
Japanese Patent Laid-Open No. 11-208494

  However, when the follow-up steering control is performed in response to the interruption or separation of the vehicle as described above, immediately after determining the switching of the preceding vehicle, the steering is temporarily performed with a large control amount to the driver. There is a risk of discomfort.

  That is, for example, immediately after it is determined that the preceding vehicle has been switched due to the interruption of the vehicle, the vehicle that is newly detected as the preceding vehicle (currently leading vehicle) is normally in a transient state of the lane change, so Located on one side. On the other hand, since the preceding vehicle is generally located in the approximate center of the vehicle lane, when the control object is shifted from the preceding vehicle to the current preceding vehicle, unnecessary large steering A control amount is calculated.

  Similarly, for example, a preceding vehicle that is in a transition state of a lane change is positioned closer to one side of the own vehicle traveling lane immediately before it is determined that the preceding vehicle is switched due to the departure of the vehicle. Since it is generally located at the approximate center of the host vehicle travel lane, an unnecessarily large steering control amount is calculated when the control object shifts from the preceding preceding vehicle to the current preceding vehicle.

  The present invention has been made in view of the above circumstances, and provides a driving support device for a vehicle that can realize follow-up steering control without a sense of incongruity even when a preceding vehicle is switched due to interruption or separation of the vehicle. For the purpose.

The present invention includes a host vehicle travel information detecting means for detecting travel information of the host vehicle,
A preceding vehicle information detecting means for detecting preceding vehicle information as traveling information of a preceding vehicle with respect to the own vehicle, a control target value is calculated according to the position of the preceding vehicle and the position of the own vehicle, and feedback control based on the control target value A steering control amount calculating means for calculating a steering control amount for following the preceding vehicle, and a control gain setting for temporarily reducing the control gain of the feedback control when the preceding vehicle detecting means detects switching of the preceding vehicle Means.

  According to the driving assistance device of the present invention, it is possible to realize follow-up steering control without a sense of incongruity even when a preceding vehicle is switched due to interruption or separation of the vehicle.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings relate to 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 steering control program, FIG. 3 is a flowchart of a gain setting program, and FIG. FIG. 5 is an explanatory diagram showing a state immediately after the preceding vehicle is switched by the interruption of the vehicle.

  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 for detecting the host vehicle speed V0 and a yaw rate sensor 8 for detecting the yaw rate γr as the host vehicle travel information detecting means. The host vehicle speed V0 is a stereo image recognition device. 4 and the control unit 5, and the yaw rate γr is 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 distance 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. That is, the stereo image recognition device 4 uses, for example, the principle of triangulation based on the shift amount of the corresponding position for a pair of stereo images in the traveling direction environment of the host vehicle 1 captured by the CCD camera of the stereo camera 3. Find distance information. 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. As the three-dimensional object data such as the vehicle, for example, 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

  Then, for example, the stereo image recognition device 4 estimates the traveling path of the host vehicle 1 (own vehicle traveling path) based on the detected white line data and the like, and automatically determines an area having a predetermined width with respect to the traveling path of the host vehicle. It is set as a vehicle travel lane (see, for example, FIGS. 4 and 5). When white line data or the like is not detected, the stereo image recognition device 4 may estimate the own vehicle traveling path based on, for example, map information input from a navigation device (not shown). Furthermore, the stereo image recognition device 4 is a vehicle (three-dimensional object) that is closest to the host vehicle 1 on the host vehicle lane, and is at a predetermined speed (for example, 0 km / h or more) in substantially the same direction as the host vehicle 1. The moving object is extracted as a preceding vehicle.

  Here, the stereo image recognition device 4 is, for example, in front of the preceding vehicle, when a new vehicle (three-dimensional object) is interrupted on the own vehicle traveling lane (the vehicle has interrupted between the preceding vehicle and the own vehicle). Case), the vehicle is extracted as a new preceding vehicle. Further, the stereo image recognition device 4 is most suitable for the own vehicle 1 when, for example, another vehicle (a three-dimensional object) exists on the own vehicle traveling lane when the preceding vehicle leaves the own vehicle traveling lane. A nearby vehicle is extracted as a new preceding vehicle. That is, the stereo image recognition device 4 appropriately switches the preceding vehicle to be controlled according to the interruption or detachment of the vehicle.

  The stereo image recognition device 4 is, for example, a preceding vehicle position (for example, a coordinate position on the XZ coordinate system with the host vehicle 1 as the origin as shown in FIG. 4), a preceding vehicle distance (inter-vehicle distance), Each data such as preceding vehicle speed ((change in distance between vehicles) + (own vehicle speed)), preceding vehicle acceleration (differential value of preceding vehicle speed), white line coordinates, white line recognition distance, own vehicle traveling path coordinates, etc. are output to the control unit 5 To do. Thus, the stereo camera 3 and the stereo image recognition apparatus 4 have a function as a preceding vehicle information detection means.

  The control unit 5 has a function of low-speed traveling control that performs constant-speed traveling control so as to maintain a traveling speed set by a driver's operation input, and a function of automatic tracking control (tracking acceleration / deceleration control and tracking steering control). When a driver turns on a main switch (not shown) and sets a desired vehicle speed with a constant speed traveling operation lever, a signal from the constant speed traveling 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.

  In addition, when the stereo image recognition device 4 recognizes a preceding vehicle while performing the constant speed traveling control, the control unit 5 automatically shifts to automatic follow-up control described later. Note that the constant speed travel control function and automatic tracking control function are available when the driver steps on the brake, when the vehicle speed exceeds the preset upper limit value, or when the main switch is turned off. In case it is to be released.

  When the vehicle travel control shifts to follow-up travel control, for example, the target inter-vehicle time is calculated and set based on the own vehicle speed, and the target acceleration is calculated based on the inter-vehicle distance from the preceding vehicle, the preceding vehicle speed, the own vehicle speed, and the target inter-vehicle time. Then, a signal is output to the throttle valve control device 10 to feedback control the opening degree of the throttle valve 11, or a deceleration signal is output to the automatic brake control device 12 to activate the automatic brake and follow running (following stop). , Including follow-up start) (follow-up acceleration / deceleration control).

  Further, when the vehicle traveling control shifts to the following traveling control and the preceding vehicle turns or changes the traveling direction, the power steering command current value ic for the electric power steering control device 13 is described according to the flowchart shown in FIG. Is calculated and output to execute follow-up steering control. Specifically, the control unit 5 calculates, for example, a target yaw rate γt as a control target value of the host vehicle 1 according to the current position of the preceding vehicle and the current position of the host vehicle 1. Then, based on the calculated target yaw rate γt, the control unit 5 calculates a power steering instruction continuous value ic as a steering control amount for following the preceding vehicle by, for example, feedback control using PID control, and performs power steering control. Output to the device 13.

  At that time, when the stereo image recognition device 4 determines to switch the preceding vehicle, the control unit 5 controls feedback control gain (in this embodiment, a proportional term gain GS, a differential term gain GV, which will be described later, and The integral term gain GH) is temporarily reduced (changed to a smaller value). Specifically, the control unit 5 sets the control gain according to, for example, a flowchart shown in FIG. 3 described later, and when it is determined that the preceding vehicle to be controlled is switched, the control gain is reduced to a predetermined value. The held gain value is held for a set time, and then gradually returned to the original gain value. When setting the control gain, the control unit 5 variably sets the amount of decrease in the control gain immediately after switching the preceding vehicle according to the traveling state of the newly switched preceding vehicle (current leading vehicle). Further, the control unit 5 variably sets the amount of increase when the control gain is returned to the original gain value according to the traveling state of the current preceding vehicle. Further, when there is a curve on the traveling path of the own vehicle, the control unit 5 sets a large increase amount when returning the control gain to the original gain value. As described above, the control unit 5 realizes functions as a steering control amount calculation unit and a control gain setting unit.

  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, the follow-up steering control of the follow-up running control will be described with reference to the flowchart of FIG. This follow-up steering control program is executed every predetermined time when a preceding vehicle is detected in front of the host vehicle 1 after the main switch of the ACC system 2 is turned on and shifts to follow-up running control. In step (hereinafter abbreviated as “S”) 101, the control unit 5 reads necessary parameters.

  Next, in S102, the control unit 5 compares the vehicle speed V0 with a preset vehicle speed threshold value V1 (for example, 35 km / h). If the vehicle speed V0 is less than the vehicle speed threshold value V1, the control unit 5 and later Proceed to On the other hand, if the control unit 5 determines in S102 that the host vehicle speed V0 is equal to or higher than the vehicle speed threshold value V1, the control unit 5 proceeds to S103, maintains the current steering angle, and then exits the program.

When it is determined in S102 that the host vehicle speed V0 is less than the vehicle speed threshold value V1 and the process proceeds to S104, the control unit 5 sets the target based on the current position of the host vehicle 1 and the position of the preceding vehicle according to the following equation (1). The running radius Rt is calculated. That is, the control unit 5 sets the coordinates of the center of gravity position of the preceding vehicle to (xt, zt) in the coordinate system having the own vehicle 1 as the origin O,
Rt = (xt ² + zt ² ) / (2 · xt) (1)
Thus, the target travel radius Rt is calculated.

In subsequent S105, the control unit 5 calculates a target yaw rate γt as a control target value by the following equation (2).
γt = V0 / Rt (2)

  When the target yaw rate γt is calculated in S105 and the process proceeds to S106, the control unit 5 executes a gain setting program, which will be described later, to calculate control gains (proportional gain GS, differential gain GV, integral gain GH).

Then, the control unit 5 proceeds to S107, calculates the power steering command current value ic as a steering control amount based on the target yaw rate γt by the following equation (3), outputs it, and then exits the program.
ic = GS · (γt−γr) + GV · (d (γt−γr) / dt)
+ GH · ∫ (γt−γr) dt (3)

  Next, the calculation of the control gain executed in S105 of the follow-up steering control program will be described with reference to the flowchart of FIG. Here, the flowchart of FIG. 3 shows a program for setting the proportional term gain GS. With this program, for example, the control unit 5 sets the proportional term gain GS in the steady state in which the same preceding vehicle is continuously detected. It is set to a preset fixed value G0, and the proportional term gain GS is variably set to a gain value lower than G0 in a transient state after switching the preceding vehicle. In addition, in this embodiment, since the calculation of the differential term gain GV and the integral term gain GH executed in S105 is the same as the calculation method of the proportional term gain GS, description thereof is omitted.

  When this program is started, the control unit 5 first checks in step S201 whether or not the preceding vehicle to be controlled has just been switched to a new preceding vehicle. Then, in S201, the control unit 5 immediately after the preceding vehicle to be controlled is switched to a new preceding vehicle (for example, FIG. 5 shows a state immediately after the preceding vehicle is switched due to a vehicle interruption). If it is determined that there is, the process proceeds to S202, and if not, the process proceeds to S219.

  When proceeding from S201 to S202, the control unit 5 sets the proportional term gain GS immediately after the preceding vehicle is switched by the processing up to S210. This proportional term gain GS is obtained by subtracting a proportional term gain GS (for example, a preset fixed value G0) set in a steady state by a lowering range (subtraction value) Gsub set based on the traveling state of the current preceding vehicle. It is set by doing. Therefore, the control unit 5 first calculates a subtraction value Gsub based on the lateral position xt of the current preceding vehicle with respect to the host vehicle 1 in S202. Here, in S202, the subtraction value Gsub is calculated, for example, with reference to a map or the like set in advance in the control unit 5, and increases as the lateral position xt (absolute value) of the current preceding vehicle increases. Is set. That is, immediately after the preceding vehicle is switched, the lateral position gap between the current preceding vehicle and the preceding preceding vehicle increases as the current preceding vehicle is laterally separated from the host vehicle 1, and the steering control amount varies greatly. It is expected that. Therefore, in S202, the subtraction value Gsub is set to a larger value as the lateral position xt (absolute value) of the current preceding vehicle is larger in order to reduce the followability with respect to the current preceding vehicle and suppress a rapid fluctuation in the steering control amount. Is done.

  In subsequent S203, the control unit 5 checks whether or not the lateral position of the preceding preceding vehicle is opposite to the lateral position of the current preceding vehicle based on the own vehicle position. In S203, if it is determined that the lateral position of the preceding preceding vehicle is opposite to the lateral position of the current preceding vehicle, the control unit 5 proceeds to S204 and is preset with respect to the currently set subtraction value Gsub. After adding the subtraction value G1 (Gsub ← Gsub + G1), the process proceeds to S205. That is, if the lateral position of the preceding vehicle is opposite to the lateral position of the current preceding vehicle, the steering direction is likely to be reversed immediately after the preceding vehicle is switched. In such a case, the steering control amount is large. It is expected to fluctuate. Therefore, in S204, the subtraction value G1 is added to the currently set subtraction value Gsub in order to reduce the follow-up performance with respect to the current preceding vehicle and suppress the rapid fluctuation of the steering control amount.

  On the other hand, if it is determined in S203 that the lateral positions of the preceding preceding vehicle and the current preceding vehicle are in the same direction with respect to the own vehicle 1, the control unit 5 proceeds to S205 as it is.

  When proceeding from S203 or S204 to S205, the control unit 5 checks whether or not the lateral velocity components of the current preceding vehicle and the preceding preceding vehicle are in directions away from each other. If it is determined in S205 that the lateral speed components of the current preceding vehicle and the preceding preceding vehicle are in directions away from each other, the control unit 5 proceeds to S206 and is set in advance with respect to the currently set subtraction value Gsub. After adding the subtraction value G2 (Gsub ← Gsub + G2), the process proceeds to S207. That is, when the speed components of the current preceding vehicle and the preceding preceding vehicle are in directions away from each other, the steering direction is likely to be reversed immediately after the preceding vehicle is switched. In such a case, the steering control amount is large. It is expected to fluctuate. Therefore, in S206, the subtraction value G2 is added to the currently set subtraction value Gsub in order to reduce the followability with respect to the current preceding vehicle and suppress a rapid fluctuation in the steering control amount.

  On the other hand, if it is determined in S205 that the lateral speed components of the current preceding vehicle and the preceding preceding vehicle are not in a direction away from each other, the control unit 5 proceeds directly to S207.

  When the process proceeds from S205 or S206 to S207, the control unit 5 checks whether or not a curve exists in front of the own vehicle traveling path. The control unit 5 proceeds to S208 if it is determined in S207 that there is a curve ahead, and proceeds to S210 if it is determined that there is no curve.

  When proceeding from S207 to S208, the control unit 5 checks whether or not the lateral speed component of the current preceding vehicle and the curve direction are opposite. If the control unit 5 determines in S208 that the lateral speed component of the current preceding vehicle is opposite to the curve direction, the control unit 5 proceeds to S209, and a subtraction value set in advance with respect to the currently set subtraction value Gsub. After adding G3 (Gsub ← Gsub + G3), the process proceeds to S210. In other words, if there is a curve ahead of the host vehicle traveling path, the preceding vehicle is likely to have a lateral velocity component in the curve direction. In such a case, the steering direction immediately after the preceding vehicle is switched. Therefore, the steering control amount is expected to vary greatly. Further, when a curve exists in front of the own vehicle traveling path, it is expected that the lateral speed of the current preceding vehicle is immediately switched to the curve direction in order to travel on the curve. Therefore, in S209, the subtraction value G3 is added to the currently set subtraction value Gsub in order to reduce the follow-up performance with respect to the current preceding vehicle and suppress the rapid fluctuation of the steering control amount.

  On the other hand, if it is determined in S208 that the lateral speed component of the current preceding vehicle matches the curve direction, the control unit 5 proceeds to S210.

  Then, when the process proceeds from S207, S208, or S209 to S210, the control unit 5 subtracts the steady-state proportional term gain V0 by the currently set final subtraction value Gsub, so that The proportional term gain GS is set (GS ← G0−Gsub).

  Note that, when setting the proportional term gain GS immediately after the preceding vehicle is switched, the subtraction value Gsub based on the determination in S203, S205, or S208 described above may be selectively performed as appropriate.

  When the process proceeds from S210 to S211, the control unit 5 sets a gain return constant k used to return the proportional term gain GS immediately after switching the preceding vehicle to the proportional term gain G0 in the steady state by the processing up to S218. . The gain return constant k is, for example, a constant for defining the increase range of the gain value according to the lateral speed Vxt of the current preceding vehicle. The initial value given based on the subtraction value Gsub is corrected by the processing up to S218. By doing so, the final value is set.

  Specifically, in S211, the control unit 5 checks whether or not the lateral position xt (absolute value) of the current preceding vehicle is separated from the host vehicle 1 by a set value or more. If it is determined in S211 that the lateral position of the current preceding vehicle is separated from the own vehicle 1 by a set value or more, the control unit 5 proceeds to S212 and sets the gain return constant k that is currently set in advance. After the added constant k1 is added (k ← k + k1), the process proceeds to S210. That is, when the lateral position of the current preceding vehicle is separated from the own vehicle 1 by a set value or more, it is expected that a curve exists in front of the own vehicle traveling path. Therefore, when the lateral position of the current preceding vehicle is separated from the host vehicle 1 by a set value or more, the proportional term gain GS is quickly returned to the steady-state gain value G0, and a smooth curve is obtained by following the current preceding vehicle. In step S212, the constant k1 is added to the currently set gain return constant k in order to realize traveling.

  On the other hand, if it is determined in S211 that the lateral position of the current preceding vehicle is not separated from the own vehicle 1 by a set value or more, the control unit 5 proceeds to S213 as it is.

  When the process proceeds from S211 or S212 to S213, the control unit 5 checks whether or not the lateral speed Vxt of the current preceding vehicle is equal to or higher than a set value. If the control unit 5 determines in S213 that the lateral speed Vxt of the current preceding vehicle is greater than or equal to the set value, the control unit 5 proceeds to S214 and sets a constant k2 set in advance with respect to the currently set gain return constant k. After the addition (k ← k + k2), the process proceeds to S215. In other words, when the preceding vehicle is switched due to the interruption of the vehicle, etc., if the lateral speed of the current preceding vehicle is high, the traveling position of the current leading vehicle is quickly moved from one side of the own vehicle traveling lane to approximately the center. It is expected to converge. Therefore, if the lateral speed of the current preceding vehicle is greater than or equal to the set value, the proportional term gain GS is quickly returned to the steady-state gain value G0 to quickly recover the steering response to the current preceding vehicle. The constant k2 is added to the currently set gain return constant k.

  On the other hand, if it is determined in S213 that the lateral speed Vxt of the current preceding vehicle is equal to or less than the set value, the control unit 5 proceeds to S215 as it is.

  When proceeding from S213 or S214 to S215, the control unit 5 checks whether or not the lateral acceleration axt of the current preceding vehicle is greater than or equal to a set value. If it is determined in S215 that the lateral acceleration axt of the current preceding vehicle is greater than or equal to the set value, the control unit 5 proceeds to S216 and sets a constant k3 set in advance with respect to the currently set gain return constant k. After the addition (k ← k + k3), the process proceeds to S216. That is, when the lateral acceleration of the current leading vehicle is greater than or equal to the set value, it is predicted that the current leading vehicle is about to cross the vehicle lane or the current leading vehicle is entering a forward curve. Is done. Therefore, when the lateral acceleration of the current preceding vehicle is greater than or equal to the set value, the proportional term gain GS is quickly restored to the steady-state gain value G0, so that the steering response to the current preceding vehicle can be quickly recovered. The constant k3 is added to the currently set gain return constant k.

  On the other hand, if it is determined in S215 that the lateral acceleration axt of the current preceding vehicle is equal to or less than the set value, the control unit 5 proceeds to S217 as it is.

  When the process proceeds from S215 or S216 to S217, the control unit 5 checks whether a curve exists ahead of the own vehicle traveling path estimated by the stereo image recognition device 4. If it is determined in S217 that there is a curve ahead of the vehicle traveling path, the control unit 5 proceeds to S218 and adds a preset constant k4 to the currently set gain return constant k ( k ← k + k4), exit the routine. That is, if a curve exists ahead of the host vehicle traveling path, the proportional term gain GS is quickly restored to the steady-state gain value G0, so that the steering response to the current preceding vehicle can be quickly restored. The constant k4 is added to the currently set gain return constant k.

  On the other hand, if it is determined in S217 that there is no curve ahead of the host vehicle traveling path, the control unit 5 exits the routine as it is.

  In setting the gain return constant k, the update of the gain return constant k based on the determination in S211, S213, S215, or S217 described above may be selectively performed as appropriate.

  In S201, when it is determined that the preceding vehicle to be controlled is not immediately after being switched to a new preceding vehicle and the process proceeds to S219, the control unit 5 sets the set time after the preceding vehicle is switched to the current preceding vehicle. Check if has passed. If it is determined in S219 that the set time has not elapsed since the preceding vehicle was switched, the control unit 5 proceeds to S220, and immediately after the previous proportional term gain GS (ie, immediately after switching to the current preceding vehicle, S210). After maintaining the proportional term gain GS) set in step, the routine is exited.

  On the other hand, if it is determined in S219 that the set time has elapsed since the preceding vehicle was switched, the control unit 5 proceeds to S221, and the gravity center position of the own vehicle traveling path and the current preceding vehicle match within a predetermined error. Find out if it is. If it is determined in S221 that the own vehicle traveling path and the center of gravity position of the current preceding vehicle match within a predetermined error, the control unit 5 proceeds to S224.

  On the other hand, in S211, if it is determined that the center of gravity of the vehicle traveling path and the current preceding vehicle do not coincide with each other, the control unit 5 proceeds to S222, and the current proportional term gain GS is equal to or larger than the gain value G0 in the steady state. Check whether or not. If the control unit 5 determines in S222 that the proportional term gain GS is less than or equal to the steady-state gain value G0, the control unit 5 proceeds to S223, and determines the current proportional term gain GS as the gain return constant k and the lateral speed of the current preceding vehicle. After updating based on Vxt (GS ← GS + k · Vxt), the routine exits.

  On the other hand, if it is determined in S222 that the proportional term gain GS is equal to or larger than the steady-state gain value G0, the control unit 5 proceeds to S224. When the process proceeds from S221 or S222 to S224, the control unit 5 sets the proportional term gain GS to the steady-state gain value G0 (GS ← G0), and then exits the routine.

  According to such an embodiment, the control target value is calculated according to the position of the preceding vehicle and the position of the host vehicle 1, and the steering control amount for following the preceding vehicle is calculated by feedback control based on the control target value. When it is determined that the preceding vehicle is switched during the follow-up steering control, the follow-up steering control without any sense of incongruity can be realized by temporarily reducing the control gain of the feedback control.

  Specifically, when switching of the preceding vehicle is detected, the control gain is reduced to a predetermined value, the reduced gain value is held for a set time, and then gradually returned to the original gain value so that there is no sense of incongruity. Follow-up steering control can be realized.

  At that time, a large amount of steering control amount can be more effectively suppressed by variably setting the amount of reduction when the control gain is lowered according to the traveling state of the newly switched preceding vehicle. . That is, for example, as the current preceding vehicle is separated from the host vehicle 1 in the lateral direction, a large change in the steering control amount can be effectively suppressed by setting the control gain lowering amount larger. . In addition, for example, when the lateral position of the preceding vehicle before switching (the preceding preceding vehicle) is opposite to the direction in which the current preceding vehicle enters the host vehicle lane, the steering gain can be increased by setting a large amount of control gain reduction. Large fluctuations in the control amount can be effectively suppressed. Further, for example, when the lateral speed of the current preceding vehicle is opposite to the lateral speed of the preceding preceding vehicle, it is possible to effectively suppress large fluctuations in the steering control amount by setting a large control gain reduction amount. it can. Also, for example, when there is a curve in front of the own vehicle traveling path, if the direction of the curve is opposite to the direction in which the current preceding vehicle enters the own vehicle lane, the control gain reduction amount is set large. By doing so, large fluctuations in the steering control amount can be effectively suppressed.

  In addition, the control gain can be reduced while suppressing a sense of incongruity for the driver by variably setting the amount of increase when the control gain is gradually returned to the original gain value according to the traveling state of the newly switched preceding vehicle. It is possible to quickly return to a constant gain value. That is, for example, when the current preceding vehicle is separated from the host vehicle 1 in the lateral direction by a set distance or more, a new advance is achieved while suppressing a sense of incongruity for the driver by increasing the control gain. Good follow-up control for the vehicle can be realized. In addition, for example, when the lateral speed of the current preceding vehicle is greater than or equal to the set value, the control gain for the new preceding vehicle can be improved while suppressing the sense of discomfort to the driver by setting the control gain to a larger range. can do. In addition, for example, when the lateral acceleration of the current preceding vehicle is greater than or equal to the set value, the control gain for the new preceding vehicle is improved while suppressing the sense of incongruity for the driver by setting a large control gain increase range. can do.

  In the above-described embodiment, an example in which the target yaw rate is calculated according to the positions of the preceding vehicle and the host vehicle 1 and the steering control amount is calculated by feedback control based on the target yaw rate has been described. For example, the target steering angle may be calculated according to the positions of the preceding vehicle and the host vehicle 1, and the steering control amount may be calculated by feedback control based on the target steering angle.

Schematic configuration diagram of a driving support device mounted on a vehicle Flow chart of following steering control program Gain setting program flowchart Explanatory drawing of the coordinate system showing the position of the preceding vehicle relative to the host vehicle Explanatory drawing which shows the state immediately after the preceding vehicle switch by vehicle interruption

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Own 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 (steering control amount calculation means, control gain setting means)
6 ... Vehicle speed sensor (own vehicle travel information detection means)
8: Yaw rate sensor (own vehicle travel information detection means)
13 ... Electric power steering control device

Claims (4)

A driving support device mounted on a vehicle,
Own vehicle running information detecting means for detecting running information of the own vehicle;
Preceding vehicle information detection means for detecting preceding vehicle information as travel information of the preceding vehicle for the host vehicle;
Steering control amount calculation means for calculating a control target value according to the position of the preceding vehicle and the position of the host vehicle, and calculating a steering control amount for following the preceding vehicle by feedback control based on the control target value;
A driving assistance apparatus comprising: control gain setting means for temporarily reducing the control gain of the feedback control when the preceding vehicle detection means detects the change of the preceding car.   When the preceding vehicle detecting means detects the change of the preceding vehicle, the control gain setting means reduces the control gain to a predetermined value, holds the reduced gain value for a set time, and then returns to the original gain value. The driving support device according to claim 1, wherein the driving support device is gradually restored.   3. The driving support apparatus according to claim 2, wherein the control gain setting means variably sets the amount of decrease when the control gain is decreased according to the traveling state of the newly switched preceding vehicle.   3. The control gain setting means variably sets an increase amount when the control gain is gradually returned to the original gain value according to a traveling state of a newly switched preceding vehicle. Or the driving assistance apparatus of Claim 3.

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