JP2018024345A - Travelling control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a travelling control device of a vehicle, which can suppress change in behavior of an own vehicle travelling in a direction of separating with respect to a driver's intended travelling path to reduce strangeness given to the driver, when travelling control for following-up a travelling lane and travelling control for following-up a preceding vehicle are switched.SOLUTION: The travelling control device of a vehicle is configured to: check whether or not a control mode should be switched from a white line control mode to a preceding vehicle control mode or the control mode should be switched from the preceding vehicle control mode to the white line control mode, in the current state (S2); when finding that the control modes should be switched, calculate a deviatio quantity between a last shape parameter of a target route in the control mode before switching and a shape parameter of the target route in the control mode after switching (S6) and set a transition mode from patterns of the deviation quantity (S7); and then perform switching processing for changing the shape parameters of the target route in the transition mode to converge the shape parameters into the shape parameters of the target route after the switching (S8).SELECTED DRAWING: Figure 10

Description

  The present invention relates to a travel control device for a vehicle that generates a target route on which the host vehicle travels and controls the follow-up travel to the target route.

  Conventionally, in a vehicle such as an automobile, the traveling lane of the host vehicle and a preceding vehicle ahead of the host vehicle are detected by a camera, a radar, and the like, and the distance between the preceding vehicle and the preceding vehicle is controlled to an appropriate distance. Follow-up travel control is known in which the position of a vehicle is controlled to control the follow-up travel to a target route whose locus is the center position of the lane or the center position of the preceding vehicle. In this follow-up travel control, the steering angle is controlled so that the position of the host vehicle coincides with the control target point of the target route, and control is performed so that the travel locus of the host vehicle changes following the target route.

  For example, Patent Document 1 discloses a technique in which when white roads can be detected, traveling control is performed to follow the lane center line, and when white lines are hidden by a preceding vehicle and cannot be detected, traveling control is performed to follow the center position of the preceding vehicle. Is disclosed. In this prior art, when it is determined from the map information that the preceding vehicle may turn right or left when following the preceding vehicle, the control gain is weakened and the meander is estimated from the lateral displacement change of the preceding vehicle. By weakening the control, an inappropriate behavior change of the host vehicle is reduced.

JP 2000-20896 A

  However, the technique disclosed in Patent Document 1 does not take into account the behavior change of the host vehicle when switching between the follow-up running to the traveling lane and the follow-up running to the preceding vehicle. For example, if the white line cannot be detected when the inter-vehicle distance decreases or the white line cannot be detected at an intersection during travel control that maintains the center of the lane of the road with the white line, the control target switches to the preceding vehicle. When the vehicle is running near the end of the lane, a vehicle behavior occurs such that the host vehicle that has been running in the center of the lane suddenly approaches the end of the lane, which gives the driver a sense of incongruity.

  On the other hand, when detecting a white line on the right turn lane side instead of the main line side on the right turn lane of a general road, etc., if the follow target is transitioned to the preceding vehicle, the follow target must be quickly transferred to the preceding vehicle. There is a possibility that the host vehicle is guided in the direction of the right turn lane, and the driver feels uncomfortable.

  The present invention has been made in view of the above circumstances, and when the following traveling control to the driving lane and the following traveling control to the preceding vehicle are switched, the own vehicle that proceeds in a direction that deviates from the traveling path of the driver. An object of the present invention is to provide a travel control device for a vehicle that can suppress a change in behavior of the vehicle and reduce a sense of discomfort given to a driver.

  A vehicle travel control apparatus according to an aspect of the present invention recognizes a travel lane of a host vehicle and a preceding vehicle ahead of the host vehicle, generates a target route on which the host vehicle travels, and controls following travel to the target route. A travel control device for a vehicle, wherein a control mode for controlling follow-up to the target route is defined as a lane control mode for controlling follow-up to the target route based on the travel lane and a travel locus of the preceding vehicle. A control mode determining unit that determines and switches to a preceding vehicle control mode that controls follow-up traveling on the target route based on, and a deviation in shape parameters of the target route before and after switching when the control mode is switched A transition mode setting unit that sets a transition mode that transitions between the lane control mode and the preceding vehicle control mode based on a quantity; The shape parameter of the target path in the over-de, and a change processing unit that changes to converge to the shape parameter of the target path after the switching.

  According to the present invention, when the follow-up running control to the driving lane and the follow-up running control to the preceding vehicle are switched, the behavior change of the own vehicle going in the direction of divergence with respect to the traveling path of the driver is suppressed, The uncomfortable feeling given to the driver can be reduced.

Configuration diagram of the travel control system Illustration of vehicle travel Explanatory drawing showing the trajectory of the control target point Explanatory diagram of a scene that rapidly shifts the control target Explanatory diagram of the scene that slowly shifts the control target Explanatory diagram showing the relationship between the deviation state of the target route and the transition mode Explanatory drawing which shows the example of transition mode M1 Explanatory drawing which shows the example of transition mode M2 Explanatory drawing which shows the example of transition mode M3 Travel control flowchart

  Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 10 denotes a travel control system for a vehicle such as an automobile, and executes travel control including autonomous automatic driving of the vehicle. This travel control system 10 is mainly composed of the travel control device 100, and includes an external environment recognition device 20, a map information processing device 30, an engine control device 40, a transmission control device 50, a brake control device 60, a steering control device 70, etc. They are connected to each other via a communication bus 150 forming a network.

  The external environment recognition device 20 recognizes the external environment around the host vehicle by various devices such as an in-vehicle camera, a millimeter wave radar, and a laser radar. In the present embodiment, the external environment recognition device 20 will mainly be described with respect to recognition of the external environment by the in-vehicle camera 1 and the image recognition device 2.

  In this embodiment, the camera 1 is a stereo camera composed of two cameras 1a and 1b that capture the same object from different viewpoints, and is a shutter-synchronized camera having an image sensor such as a CCD or CMOS. is there. These cameras 1a and 1b are, for example, arranged with a predetermined baseline length in the vicinity of a room mirror inside the front window at the upper part of the vehicle interior.

  A pair of left and right images captured by the camera 1 is processed by the image recognition device 2. The image recognition device 2 obtains a pixel shift amount (parallax) at the corresponding position of the left and right images by stereo matching processing, converts the pixel shift amount into luminance data or the like, and generates a distance image. From the principle of triangulation, the point on the distance image is a point in real space where the vehicle width direction of the own vehicle, that is, the left-right direction is the X axis, the vehicle height direction is the Y axis, and the vehicle length direction, that is, the distance direction is the Z axis. The coordinates are transformed, and the white line (lane) of the road on which the host vehicle travels, the obstacle, the vehicle traveling in front of the host vehicle, and the like are recognized three-dimensionally.

  A road white line as a lane can be recognized by extracting a point group that is a candidate for a white line from an image and calculating a straight line or a curve connecting the candidate points. For example, in a white line detection region set on an image, an edge whose luminance changes more than a predetermined value is detected on a plurality of search lines set in the horizontal direction (vehicle width direction), and one set of white lines is set for each search line. A start point and a white line end point are detected, and an intermediate region between the white line start point and the white line end point is extracted as a white line candidate point.

  Then, the time series data of the spatial coordinate position of the white line candidate point based on the vehicle movement amount per unit time is processed to calculate a model that approximates the left and right white lines, and the white line is recognized by this model. As an approximate model of the white line, an approximate model obtained by connecting linear components obtained by the Hough transform, or a model approximated by a curve such as a quadratic equation can be used.

  The map information processing apparatus 30 includes a map database, measures the position of the host vehicle based on signals from GPS satellites, etc., and collates with map data. The map database includes map data for displaying vehicle route guidance and the current position of the vehicle, and high-definition map data for performing driving support control including automatic driving.

  The map information processing device 30 presents the driving route guidance and traffic information based on the comparison between the positioning result of the own vehicle position and the map data to the driver via a display device (not shown), and the own vehicle and the preceding vehicle travel. Road shape data such as the curvature, lane width, and shoulder width of the road, and map information for travel control such as road azimuth, road white line type, and number of lanes are output.

  The engine control device 40 controls the operation state of an engine (not shown) based on signals from various sensors that detect the engine operation state and various control information transmitted via the communication bus 150. The engine control device 40 is, for example, fuel injection control, ignition timing control, electronic control throttle based on intake air amount, throttle opening, engine water temperature, intake air temperature, air-fuel ratio, crank angle, accelerator opening, and other vehicle information. Engine control is performed mainly for valve opening control.

  The transmission control device 50 supplies hydraulic pressure to be supplied to an automatic transmission (not shown) based on signals from sensors for detecting a shift position, vehicle speed, and the like and various control information transmitted via the communication bus 150. And control the automatic transmission according to a preset shift characteristic.

  The brake control device 60 controls a four-wheel brake device (not shown) independently of a driver's brake operation based on, for example, a brake switch, four-wheel wheel speed, steering wheel angle, yaw rate, and other vehicle information. To do. Further, the brake control device 60 calculates the brake fluid pressure of each wheel based on the brake force of each wheel, and performs anti-lock brake system, side slip prevention control, and the like.

  The steering control device 70 controls assist torque by an electric power steering motor (not shown) provided in the vehicle steering system based on, for example, vehicle speed, driver steering torque, steering wheel angle, yaw rate, and other vehicle information. In addition, the steering control device 70 drives and controls the electric power steering motor with a steering amount that follows the traveling locus of the preceding vehicle when traveling following the preceding vehicle traveling in front of the host vehicle according to an instruction from the traveling control device 100. To do.

  Next, the travel control device 100 that is the center of the travel control system 10 will be described. The travel control device 100 generates a target route that is a target of the following traveling of the host vehicle based on the recognition result of the external environment by the external environment recognition device 20, and the engine control device 40 so as to travel along the target route. The travel control via the transmission control device 50, the brake control device 60, and the steering control device 70 is executed.

  Specifically, when the white line on the road is stably recognized, the traveling control apparatus 100 performs control so as to follow the target route having the locus at the center position of the left and right white lines. On the other hand, when there is no white line on the road or the white line cannot be recognized and the preceding vehicle is supplemented in front of the host vehicle, control is performed so as to follow the target route generated based on the travel locus of the preceding vehicle.

  Furthermore, when the preceding vehicle is losing sight of the white line in a situation where the preceding vehicle is traveling by the end of the lane, the traveling control device 100 gradually shifts the control target to the preceding vehicle. In addition, if the white line is lost in the right turn lane at the intersection after the white line is detected, the vehicle is prevented from being guided toward the right turn lane by rapidly moving the control target to the preceding vehicle. . This prevents the vehicle behavior from becoming unstable due to frequent switching between the travel control to the target route based on the white line and the travel control to the target route based on the preceding vehicle, and reduces the uncomfortable feeling given to the driver. it can.

  For this reason, as shown in FIG. 1, the travel control device 100 includes a target route generation unit 101, a white line control permission determination unit 102, a preceding vehicle control permission determination unit 103, a control mode determination unit 104, a transition mode setting unit 105, A switching processing unit 106 and a control unit 107 are provided. Furthermore, the target route generation unit 101 includes a white line route generation unit 101a that generates a target route based on a white line, and a preceding vehicle route generation unit 101b that generates a target route based on the travel locus of the preceding vehicle. .

  The target route generation unit 101 executes a process of generating a target route in parallel in each of the white line route generation unit 101a and the preceding vehicle route generation unit 101b in a state where the white line and the preceding vehicle are recognized. The target route generated by the white line route generation unit 101a and the target route generated by the preceding vehicle route generation unit 101b are basically generated by the same process.

  That is, the white line path generation unit 101a sets the center position of the left and right white lines as a target point, and uses the trajectory of the target point as a target path. Further, the preceding vehicle route generation unit 101b uses the center position in the width direction of the rear region of the preceding vehicle as a target point, and similarly uses the locus of this target point as the target route.

  In the present embodiment, an example will be described in which a target route is generated by expressing a locus of a target point with a quadratic curve.

(A) In the case of a white line Each white line candidate point detected on an image is mapped to a real space coordinate system with respect to the image coordinate system. The white line candidate points on this image are, for example, candidate points from about 7 to 8 m on the near side to about 100 m on the far side, and all these white line candidate points are mapped to the real space. Then, the white line candidate points that can be detected on the image are combined with the past white line data estimated based on the movement amount of the host vehicle, and an approximate curve for each candidate point is identified.

(B) In the case of a preceding vehicle The coordinates of the center of the back of the preceding vehicle are set as a point P. On the other hand, based on the following formulas (1) to (4), the moving amount of the own vehicle is updated every moment. The trajectory point group of the preceding vehicle is created. An approximate curve is identified for this locus point group.

Specifically, for example, a candidate point P that is a target for each frame is obtained based on the amount of movement of the host vehicle per frame of the captured image of the camera 1, and a curve that approximates the point cloud of the candidate point P is targeted. Calculate as a route. Specifically, based on the relationship shown in FIG. 2, based on the vehicle speed V of the host vehicle CR and the yaw angle θ obtained from the yaw rate of the host vehicle CR, the frame rate Δt (time until the captured image is updated by one frame). The movement amounts Δx and Δz to the host vehicle CR ′ are calculated using the following equations (1) and (2).
Δx = V · Δt · sin θ (1)
Δz = V · Δt · cos θ (2)

Next, as shown in the following equations (3) and (4), the movement of the host vehicle with respect to the candidate point Pold (Xold, Zold) in the vehicle fixed coordinate system (X, Z) detected before the previous frame After subtracting the quantities Δx and Δz, the coordinates of the candidate point Ppre (Xpre, Zpre) in the current frame are calculated by performing coordinate transformation to the vehicle fixed coordinate system (X ′, Z ′) in the current frame. .
Xpre = (Xold−Δx) · cos θ− (Zold−Δz) · sin θ (3)
Zpre = (Xold−Δx) · sin θ + (Zold−Δz) · cos θ (4)

Then, by applying a least square method, for example, to the point group of these candidate points, as shown in the following equation (5), a path PH expressing the locus of the candidate points with a quadratic curve is obtained, This route PH is set as a target route (see FIG. 3). In equation (5), coefficients A, B, and C represent path components constituting the target path, coefficient A is the curvature component of the target path, and coefficient B is the yaw angle component of the target path with respect to the host vehicle (the longitudinal direction of the host vehicle). The angle component between the axis and the target route (tangent)) and the coefficient C indicate the position component (lateral position component) in the lateral direction of the target route with respect to the host vehicle.
X = A · Z ² + B · Z + C (5)

  The target path by the white line may be calculated from the center target point using the center position of the left and right white line candidate points as a target point. The curve of equation (5) is calculated for each of the white lines, and the locus of the center position obtained from the left and right curves is set as the target route.

  The white line control permission determination unit 102 evaluates the reliability and stability when traveling control is performed using only white line information. When it is determined that the reliability and stability satisfy the predetermined condition, the white line control permission flag FLGw that permits execution of the traveling control based on the white line information is turned ON.

  The reliability and stability of the driving control based on the white line information are evaluated according to the following conditions (J1) and (J2). If all of these conditions are satisfied, the driving control is stable and reliable with only the white line information. The white line control permission flag FLGw is set to ON (FLGw = 1) by determining that it can be executed.

(J1) Length of white line The length of the white line obtained by the external environment recognition device 20 is evaluated. When the length of the white line is equal to or longer than a threshold (for example, 20 m or longer), it is determined that the traveling control can be performed without causing an unstable control state due to intermittent or lost white lines.

(J2) Time change of shape parameter representing lane shape Time change of lane shape parameter due to white line, ie, white line curvature component represented by coefficient A in equation (5), own vehicle of white line represented by coefficient B The time change of the lateral position component of the white line represented by the yaw angle component and the coefficient C with respect to the host vehicle is evaluated. When the time change of each parameter is smoothly changing below a threshold value, it is determined that traveling control can be executed by excluding a scene in which a white line shape such as a right turn lane changes rapidly.

  The preceding vehicle control permission determination unit 103 evaluates reliability and stability when traveling control is performed using only the preceding vehicle information, and determines that the reliability and stability satisfy a predetermined condition. The preceding vehicle control permission flag FLGc that permits the execution of the traveling control based on is turned on.

  The reliability and stability of the traveling control based on the preceding vehicle information are evaluated according to the following conditions (J3) to (J5), and when all of these conditions are satisfied, the traveling is stable and reliable with only the preceding vehicle information. It is determined that the control can be executed, and the preceding vehicle control permission flag FLGc is turned ON (FLGc = 1).

(J3) Curvature curvature of the preceding vehicle The curvature of the target route based on the preceding vehicle information, that is, the curvature of the trajectory of the preceding vehicle represented by the coefficient A in the equation (5) is evaluated. When the curvature of the trajectory of the preceding vehicle is within a predetermined range, it is determined that traveling control can be executed excluding left and right turns.

(J4) Lateral position of the trajectory of the preceding vehicle The lateral position of the target route based on the preceding vehicle information, that is, the lateral position of the trajectory of the preceding vehicle represented by the coefficient C in the equation (5) is evaluated. When the lateral position of the preceding vehicle with respect to the host vehicle is within a predetermined range, it is determined that the traveling control can be executed stably.

(J5) Direction indicator of the preceding vehicle Check whether the direction indicator of the preceding vehicle is lit. When the preceding vehicle does not turn on the direction indicator, it is determined that the traveling control can be stably executed by excluding the course changing operation such as turning left or right or changing the lane.

  The control mode determination unit 104 refers to the white line control permission flag FLGw and the preceding vehicle control permission flag FLGc, and determines the control mode of the traveling control according to the conditions shown in the following (J6) to (J8).

(J6) FLGw = 1
When the white line control permission flag FLGw is ON (FLGw = 1), regardless of the state of the preceding vehicle control permission flag FLGc, the control mode of the traveling control is set to the control mode (white line control) for following the target route based on the white line information. Mode).

(J7) FLGw = 0, FLGc = 1
When the white line control permission flag FLGw is OFF (FLGw = 0) and the preceding vehicle control permission flag FLGc is ON (FLGc = 1), the control mode of the traveling control is set to follow the target route based on the preceding vehicle information. The mode (preceding vehicle control mode) is determined.

(J8) FLGw = 0, FLGc = 0
In this case, since it is considered that the white line and the preceding vehicle cannot be recognized for some reason, this control system is turned OFF.

  When the control mode determined by the control mode determination unit 104 is switched, the transition mode setting unit 105 selects an appropriate one of a plurality of preset transition modes according to the deviation state of the shape parameter of the target route before and after the switching. Transition mode is selected and the transition time for switching between the white line control mode and the preceding vehicle control mode is optimized. In the following description, the case of transition from the white line control mode to the preceding vehicle control mode will be mainly described, but the same applies to the case of transition from the preceding vehicle control mode to the white line control mode.

  When the road traffic environment is viewed comprehensively, the curvature of the target route based on the white line information deviates from the curvature of the target route based on the preceding vehicle information, and the control based on the white line is not permitted (FLGw = 0). In most cases, a scene that detects a partial white line such as a right turn lane or a road surface pattern at an intersection occupies the majority. In such a scene, it is necessary to rapidly change the control amount necessary for the control from the white line to the preceding vehicle.

  For example, as shown in FIG. 4, in a scene in which an intersection appears while the host vehicle CR is traveling on a route along the white line Lw and a right turn lane Lwr is detected, the curvature component Aw of the white line and the curvature component of the trajectory of the preceding vehicle up to that point are detected. Ac greatly deviates from Ac. In such a scene, it is necessary to rapidly shift the control target from the white line Lw to the preceding vehicle CR1 in order to prevent the departure to the right turn lane Lwr side.

  On the other hand, if the shape of the white line and the shape of the trajectory of the preceding vehicle are maintained substantially parallel for a predetermined time, it is considered that the preceding vehicle is deviating from the center position of the white line. Can do. For example, as shown in FIG. 5, when the host vehicle CR is traveling with the center position O of the white line Lw as a target, and the preceding vehicle CR1 is traveling with an offset amount λ from the center position O of the white line Lw, The trajectory of the preceding vehicle CR1 has a shape substantially parallel to the shape of the white line Lw.

  In such a state, when the white line Lw is lost and the follow-up control to the white line is not permitted, for example, if the target point of the travel control is suddenly brought close to the preceding vehicle CR1, the driver is greatly discomforted. Become. Therefore, in such a scene, it is desirable to make a gradual transition over time from the target route based on the white line information to the target route based on the preceding vehicle information.

  Therefore, the transition mode setting unit 105 includes a plurality of transition modes having different transition times between the white line control mode and the preceding vehicle control mode, and selects an appropriate mode according to the scene from the plurality of transition modes. To do. In the present embodiment, one mode is selected from the three transition modes M1, M2, and M3.

  The transition modes M1, M2, and M3 use the transition mode M2 as a standard mode, and the transition mode M1 has a shorter transition time T1 (for example, 1 sec) than the transition time T2 (for example, 2 sec) of the transition mode M2. The transition mode M3 is set as a mode having a longer transition time T3 (for example, 4 sec).

  Further, the divergence state of the shape parameter of the target route is the difference between the curvature component Aw of the target route based on the white line and the curvature component Ac of the target route based on the trajectory of the preceding vehicle, the yaw angle component Bw of the target route based on the white line, and the preceding Evaluation is based on the difference between the yaw angle component Bc of the target route based on the trajectory of the vehicle and the difference between the lateral position component Cw of the target route based on the white line and the lateral position component Cc of the target route based on the trajectory of the preceding vehicle.

  The amount of deviation between the shape parameters may be a difference in instantaneous values when the control mode is switched, or may be an average value in the past predetermined time (several seconds). In particular, regarding the difference between the lateral position components Cw and Cc, it is desirable to determine the amount of deviation in a relatively long span (several seconds to several tens of seconds). In the present embodiment, a predetermined threshold is provided for each divergence amount, and the magnitude of the divergence amount is determined in two stages of “large” and “small”.

  FIG. 6 shows transitions when the “large” and “small” patterns of the target path shape parameter deviation amounts (Aw−Ac), (Bw−Bc), and (Cw−Cc) are classified into 1 to 8 The correspondence with the mode is shown. Here, regardless of the magnitude of the deviation (Aw−Ac) of the curvature component, the deviation (Bw−Bc) of the yaw angle component and the deviation (Cw−Cc) of the lateral position component are both “large”. The standard transition mode M2 is set to correspond to the patterns 1 and 4.

  In contrast, when the deviation amount (Aw−Ac) of the curvature component is “large”, at least one of the deviation amount (Bw−Bc) of the yaw angle component and the deviation amount (Cw−Cc) of the lateral position component is “small”. , And even if the deviation amount (Aw−Ac) of the curvature component and the deviation amount (Cw−Cc) of the lateral position component are “small”, the deviation amount of the yaw angle component In the pattern 7 in which (Bw−Bc) is “large”, it is assumed that the control target needs to be moved quickly, so the transition mode is the transition mode M1 whose transition time is shorter than the standard. Further, in the patterns 6 and 8 in which the deviation amount (Aw−Ac) of the curvature component and the deviation amount (Bw−Bc) of the yaw angle component are both “small”, the shape of the white line and the shape of the locus of the preceding vehicle are approximately. Since it is assumed to be parallel, the transition mode is a transition mode M3 having a transition time longer than the standard.

  The switching processing unit 106 outputs the target route parameters to the control unit 107 in accordance with the control mode determined by the control mode determination unit 104. That is, when the white line control permission flag FLGw is ON and in the white line control mode, the shape parameter of the target route based on the white line is output to the control unit 107, and when the preceding vehicle control permission flag FLGc is ON and in the preceding vehicle control mode. Outputs the shape parameter of the target route based on the preceding vehicle to the control unit 107.

  Further, when switching from the white line control mode to the preceding vehicle control mode, or when switching from the preceding vehicle control mode to the white line control mode, the switching processing unit 106 is represented by the following equations (6) to (8). , Shape parameter As. Of target path in transition mode. Let Bs and Cs be values obtained by adding offsets according to the deviation amounts of the shape parameters before and after switching to the shape parameters A_target, B_target, and C_target of the target path in the control mode after switching. The offset amount changes so as to decrease with the passage of time by gains Ga, Gb, and Gc that become 0 after the transition time determined by the transition mode has elapsed, and finally the shape parameter As. Bs and Cs converge to the shape parameters A_target, B_target, and C_target of the switching destination.

As = A_target + Ga · (A_target_off−A_target_on) (6)
Bs = B_target + Gb (B_target_off−B_target_on) (7)
Cs = C_target + Gc (C_target_off−C_target_on) (8)
here,
A_target: Curvature component of target path after switching A_target_off: Last curvature component of target path that was OFF before switching A_target_on: Last curvature component of target path that was ON before switching B_target: Target path after switching Yaw angle component B_target_off: Last yaw angle component of target path that was OFF before switching B_target_on: Last yaw angle component of target path that was ON before switching C_target: Lateral position component of target path after switching C_target_off: Last lateral position component of the target path that was OFF before switching C_target_on: Last lateral position component of the target path that was ON before switching Ga, Gb, Gc: 100 at the time of switching at a ratio that reflects the offset Gain that becomes 0 after the elapsed time determined in transition mode as a percentage

  For example, when switching from the white line control mode to the preceding vehicle control mode, in the transition mode M1, as shown in FIG. 7, the curvature component Aw, the yaw angle component Bw, and the lateral position component Cw of the target route in the white line control mode are: Each of the gains Ga, Gb, and Gc changes rapidly, and converges to the curvature component Ac, yaw angle component Bc, and lateral position component Cc in the preceding vehicle control mode at the transition time T1 (for example, 1 sec).

  As shown in FIG. 8, in the transition mode M2, the curvature component Aw, the yaw angle component Bw, and the lateral position component Cw of the target path in the white line control mode are changed by the gains Ga, Gb, and Gc, respectively. It converges to the curvature component Ac, the yaw angle component Bc, and the lateral position component Cc in the preceding vehicle control mode in the transition time T2 (for example, 2 sec) longer than the time T1.

  Further, in the transition mode M3, as shown in FIG. 9, the curvature component Aw, the yaw angle component Bw, and the lateral position component Cw of the target path in the white line control mode are changed by the gains Ga, Gb, and Gc, respectively, and the transition time T3. (For example, 4 sec), and gradually converges to the curvature component Ac, yaw angle component Bc, and lateral position component Cc in the preceding vehicle control mode.

  The control unit 107 corrects the current steering angle via the steering control device 70 so that the center position in the vehicle width direction of the host vehicle coincides with the target point on the target route, and controls the follow-up traveling on the target route. To do. The steering control to the control target point is performed by feedback control for a deviation δ (see FIG. 2) between the estimated lateral position of the host vehicle and the target point at a predetermined distance when traveling at the current steering angle, and between the target route and the host vehicle. The feedback control for the relative yaw angle and the feedforward control for the change in the curvature of the target path are mainly executed.

  The estimated lateral position of the host vehicle at a predetermined distance can be calculated from the steering angle, the vehicle speed, the vehicle-specific stability factor, the wheel base, the steering gear ratio, and the yaw rate of the host vehicle detected by the sensor. It is also possible to calculate by using.

For example, as shown in the following equation (9), the steering control amount of the feedforward control with respect to the curvature component A of the target route and the relative yaw angle θy between the target route and the host vehicle based on the yaw angle component B of the target route. The target steering angle αref is calculated by adding the steering control amount of the feedback control to the above and the steering control amount of the feedback control with respect to the deviation δ between the estimated lateral position of the vehicle based on the lateral position component C of the target route and the target point. And output to the steering control device 70.
αref = Gff · A + Gy · θy + Gf · δ (9)
Where Gff: feed forward gain for curvature component A of the target path
Gy: feedback gain for the relative yaw angle θy between the target route and the vehicle
Gf: feedback gain for deviation δ of the lateral position between the host vehicle and the target route when traveling at the current steering angle

  The steering control device 70 calculates a target steering torque based on the deviation between the target steering angle αref and the actual steering angle, and controls the electric power steering motor. Specifically, the control to the target torque is executed as current control of the electric power steering motor. For example, the electric power steering motor is driven by a drive current by PID control.

  Next, the travel control program processing in the travel control apparatus 100 will be described with reference to the flowchart shown in FIG.

  In this travel control, in the first step S1, it is checked whether the white line on the road and the preceding vehicle ahead of the host vehicle can be recognized. If the white line and the preceding vehicle can be recognized, the process proceeds to step S2, and the current control state is changed from the white line control mode to the preceding vehicle control mode with reference to the white line control permission flag FLGw and the preceding vehicle control permission flag FLGc. It is checked whether or not the vehicle is switched from the preceding vehicle control mode to the white line control mode.

  In step S2, if the current control state is not a state for switching the control mode, the process proceeds to step S3 to check whether the current control mode is the white line control mode. If it is the white line control mode, follow-up running control for following the target route based on the white line information is executed in step S4. If it is not the white line control mode but the preceding vehicle control mode, step S5 is executed. Then, follow-up running control for following the target route based on the preceding vehicle information is executed.

  On the other hand, when the current control state is a state for switching the control mode in step S2, the process proceeds from step S2 to step S6. In step S6, the amount of deviation (difference in curvature component, difference in yaw angle component, lateral position) between the last shape parameter of the target path in the control mode before switching and the shape parameter of the target path in the control mode after switching. Component difference) is calculated.

  Next, the process proceeds from step S6 to step S7, the shape parameter divergence amount is compared with a threshold value, and each is classified into “large” and “small”. Sets the transition mode when shifting the control mode. In the present embodiment, one of the transition modes M1, M2, and M3 is selected based on the “large” and “small” patterns of the deviation amount.

  Then, in step S8, a switching process for changing the shape parameter of the target route in the transition mode to finally converge to the shape parameter of the target route after switching is performed. At this time, the shape parameter in the transition mode is a value obtained by adding the offset amount according to the deviation amount before and after the switching to the shape parameter after the switching, and after the transition time determined by the transition mode has elapsed, the offset amount is 0.

  As described above, in the present embodiment, when the control mode for controlling the follow-up traveling to the target route is switched, the transition mode is set based on the deviation amount of the shape parameter of the target route before and after the switching. The target path shape parameter is changed so as to converge to the target path shape parameter of the control mode after switching. As a result, when the follow-up running control to the driving lane and the follow-up running control to the preceding vehicle are switched, it is possible to suppress the behavior change of the own vehicle going in the direction of divergence with respect to the traveling path of the driver, The uncomfortable feeling given to the driver can be reduced.

DESCRIPTION OF SYMBOLS 10 Travel control system 20 External environment recognition apparatus 100 Travel control apparatus 101 Target route production | generation part 101a White line route production | generation part 101b Prior vehicle route production | generation part 102 White line control permission judgment part 103 Prior vehicle control permission judgment part 104 Control mode determination part 105 Transition mode Setting unit 106 Switching processing unit 107 Control unit M1, M2, M3 transition mode T1, T2, T3 transition time

Claims (5)

A travel control device for a vehicle that recognizes a travel lane of the host vehicle and a preceding vehicle ahead of the host vehicle, generates a target route on which the host vehicle travels, and controls tracking following the target route,
A control mode for controlling the follow-up travel to the target route, a lane control mode for controlling the follow-up travel to the target route based on the travel lane, and a follow-up travel to the target route based on the travel locus of the preceding vehicle. A control mode determination unit that determines and switches to any one of the preceding vehicle control modes to be controlled;
When the control mode is switched, a transition mode setting unit that sets a transition mode that transitions between the lane control mode and the preceding vehicle control mode based on a deviation amount of the shape parameter of the target route before and after the switching. When,
And a switching processing unit that changes the shape parameter of the target route in the transition mode so as to converge to the shape parameter of the target route after the switching in the transition mode. apparatus.   The vehicle travel control device according to claim 1, wherein the transition mode setting unit sets the transition mode as a mode in which a transition time differs according to a deviation amount of a shape parameter of the target route before and after switching. .   The shape parameter of the target route is configured by a curvature component of the target route, an angle component between the host vehicle and the target route, and a lateral position component between the host vehicle and the target route. The vehicle travel control device according to claim 1, wherein   When the lane control mode is permitted, the control mode determination unit determines the control mode as the lane control mode regardless of the permission state of the preceding vehicle control mode, and the lane control mode is not permitted. The vehicle travel control apparatus according to any one of claims 1 to 3, wherein the control mode is determined to be the preceding vehicle control mode under a condition in which the preceding vehicle control mode is permitted.   5. The switch according to claim 1, wherein the switching processing unit changes the shape parameter of the target route in the transition mode by a gain that reflects a deviation amount of the shape parameter of the target route before and after the switching. The vehicle travel control device according to claim 1.

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