JP2018154304A - Vehicle travel control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain stable and smooth traveling by mitigating the influence of a disturbance suddenly applied to a own vehicle during traveling following a target route. SOLUTION: A travel control device 100 executes a follow-up travel to a target route generated by a target route generation unit 101 by controlling a target steering angle set by a target steering angle setting unit 102. At that time, when the disturbance prediction unit 103 predicts that a sudden disturbance will be applied to the own vehicle, the follow-up control gain correction unit 104 corrects the gain of the feedforward control with respect to the curvature of the target path at the target steering angle. The traveling state of the own vehicle is adjusted in advance in preparation for the disturbance applied to the vehicle, and the influence when the disturbance is actually applied to the own vehicle is mitigated so that stable and smooth running can be maintained. [Selection diagram] Fig. 1

Description

  The present invention relates to a travel control device for a vehicle that controls travel following a target route on which the host vehicle travels.

  In vehicles such as automobiles, the traveling lane of the host vehicle and the preceding vehicle ahead of the host vehicle are detected by a camera, radar, etc., and the distance between the preceding vehicle and the preceding vehicle is controlled to an appropriate distance. A follow-up running control technique for controlling the vehicle so as to travel along a target route with the center position of the vehicle as a locus has been put into practical use.

  In this follow-up running control, the steering angle is controlled so that the traveling locus of the host vehicle coincides with the target route. However, when a disturbance such as a crosswind is suddenly applied to the host vehicle, the steering correction for the sudden disturbance is delayed. This may cause the driver to feel uneasy or uncomfortable.

  For this reason, for example, in Patent Document 1, a change pattern of the lateral position of a preceding vehicle is detected from an image ahead of the host vehicle, and the degree of instability of the preceding vehicle is determined from the change pattern of the preceding vehicle lateral position. And a technique for changing the control state of the follow-up control for the preceding vehicle is disclosed.

JP 2004-220348 A

  However, the technique disclosed in Patent Document 1 increases the target inter-vehicle distance or the deceleration control when the unstable traveling state of the preceding vehicle itself is detected with respect to the follow-up control that follows the preceding vehicle with a certain inter-vehicle distance. The following control state is changed to a state in which only the vehicle tracking is performed or the tracking control is canceled, and it is difficult to maintain smooth running by dealing with a disturbance suddenly applied to the host vehicle.

  The present invention has been made in view of the above circumstances, and is a vehicle travel control device that can reduce the influence of a disturbance suddenly applied to the host vehicle during travel following the target route and maintain stable smooth travel. The purpose is to provide.

  A travel control device for a vehicle according to an aspect of the present invention is a travel control device for a vehicle that generates a target route on which the host vehicle travels, and controls tracking following the target route. A disturbance prediction unit that predicts a disturbance applied to the host vehicle based on a change in behavior, and a target steering that causes the traveling track of the host vehicle to follow the target path when the disturbance prediction unit predicts a disturbance to the host vehicle. And a follow-up control gain correction unit that corrects the corner control gain.

  ADVANTAGE OF THE INVENTION According to this invention, the influence of the disturbance abruptly added to the own vehicle during driving | running | working following a target path | route can be eased, and the stable smooth driving | running can be maintained.

Configuration diagram of the travel control system Explanatory diagram of following travel control for target route Explanatory diagram showing behavior change of preceding vehicle due to disturbance Explanatory drawing which shows lateral position variation | change_quantity of the preceding vehicle in FIG. Explanatory diagram showing behavior change of preceding vehicle and oncoming vehicle due to disturbance Explanatory drawing which shows lateral position variation | change_quantity of the preceding vehicle and oncoming vehicle in FIG. Explanatory diagram showing the behavior when there is no disturbance to the preceding vehicle and the oncoming vehicle Explanatory drawing which shows lateral position variation | change_quantity of the preceding vehicle and oncoming vehicle in FIG. Flow chart of travel control processing Flow chart of target steering angle setting process

  Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a travel control system for a vehicle such as an automobile, which performs travel control including autonomous automatic driving of the vehicle. The travel control system 1 is centered on the travel control device 100, and includes an external environment recognition device 10, a positioning device 20, a map information processing device 30, an engine control device 40, a transmission control device 50, a brake control device 60, and a steering control device. 70, an alarm control device 80, etc. are connected to each other via a communication bus 150 forming an in-vehicle network.

  The external environment recognition device 10 is based on detection information of an object around the host vehicle by various devices such as an in-vehicle camera unit 11, a radar device 12 such as a millimeter wave radar or a laser radar, and infrastructure communication such as road-to-vehicle communication or vehicle-to-vehicle communication. The external environment around the host vehicle is recognized based on the acquired traffic information, the position information of the host vehicle measured by the positioning device 20, the map information from the map information processing device 30, and the like.

  Hereinafter, as external environment recognition processing in the external environment recognition apparatus 10, processing that recognizes the external environment by processing an image captured by the camera unit 11 will be mainly described. The camera unit 11 is, for example, a stereo camera composed of two cameras that capture the same object from different viewpoints, and is composed of a shutter-synchronized camera having an image sensor such as a CCD or CMOS. The camera unit 11 is configured, for example, such that two cameras are disposed on the left and right sides in the vehicle width direction with a predetermined baseline length in the vicinity of a room mirror inside the front window at the upper part of the vehicle interior.

  For a pair of left and right images captured by the camera unit 11 as a stereo camera, for example, a pixel shift amount (parallax) at a corresponding position of the left and right images is obtained by stereo matching processing, and the pixel shift amount is converted into luminance data or the like. A distance image is generated. The point on the distance image is a point in the real space based on the principle of triangulation, 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 converted into a white line (lane) on the road on which the host vehicle travels, an obstacle, a vehicle traveling in front of the host vehicle, and the like are three-dimensionally recognized.

  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 positioning device 20 performs positioning mainly by satellite navigation that measures the position of the own vehicle based on signals from a plurality of satellites. The positioning of the signals (radio waves) from the satellites and the influence of multipath due to the reflection of radio waves, etc. When the positioning accuracy deteriorates, positioning is performed by autonomous navigation in which the position of the vehicle is determined based on the heading and moving distance of the host vehicle. Note that the positioning device 20 may be integrally provided with a communication unit that acquires traffic information by infrastructure communication such as road-to-vehicle communication and vehicle-to-vehicle communication.

  In positioning by satellite navigation, for example, a signal including information on orbits and times transmitted from a plurality of navigation satellites such as GPS satellites is received, and the self-position of the host vehicle is determined based on the received signal as a three-dimensional absolute position. As positioning. In addition, positioning by autonomous navigation is based on the relative direction of the calculated position (own vehicle position) based on the traveling direction of the own vehicle detected by the direction sensor and the moving distance of the own vehicle calculated from the vehicle speed pulse output from the vehicle speed sensor. Measure the position of the vehicle as a typical change.

  The map information processing apparatus 30 includes a map database DB, and specifies and outputs the position on the map data of the map database DB from the position data of the own vehicle measured by the positioning apparatus 20. In the map database DB, for example, navigation map data that is mainly referred to when displaying vehicle route guidance and the current position of the vehicle, and driving support control including automatic driving, which is more detailed than the map data, are provided. Map data for travel control which is referred to when performing is stored.

  In the map data for navigation, the previous node and the next node are linked to the current node via links, and information about traffic lights, road signs, buildings, etc. is stored in each link. ing. On the other hand, high-definition map data for traveling control has a plurality of data points between a node and the next node. These data points include road shape data such as the curvature, lane width, and shoulder width of the road on which the vehicle is traveling, and data for driving control such as road azimuth, road white line type, and number of lanes. It is stored with attribute data such as date of data update.

  The map information processing apparatus 30 collates the positioning result of the vehicle position with the map data, and presents driving route guidance and traffic information based on the collation result to the driver via a display device (not shown). Further, the map information processing device 30 communicates road shape data such as curvature, lane width, and shoulder width of the road on which the vehicle travels, and map information for travel control such as road azimuth, road white line type, and number of lanes. Transmit via the bus 150. The travel control map information is mainly transmitted to the travel control device 100, but is also transmitted to other control devices as necessary.

  Further, the map information processing apparatus 30 performs maintenance management of the map database DB, verifies the nodes, links, and data points of the map database DB and keeps them always up-to-date, and for areas where no data exists on the database. Create and add new data to build a more detailed database. Data update in the map database DB and addition of new data are performed by collating the position data measured by the positioning device 20 with the data stored in the map database DB.

  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 steering torque by an electric power steering motor (not shown) provided in the steering system based on, for example, vehicle speed, driver steering torque, steering wheel angle, yaw rate, and other vehicle information. As will be described later, in the steering control via the electric power steering motor, when the host vehicle automatically travels following the target route, the control of the steering control against a disturbance that is expected to be applied at a predetermined front position. The gain is adjusted in advance.

  The alarm control device 80 is a device that generates an alarm when an abnormality occurs in various devices of the vehicle. For example, a visual output such as a monitor, a display, and an alarm lamp, and an audio output such as a speaker and a buzzer. Warning / notification is performed using at least one of the above. Further, when the driving support control including the automatic driving is stopped by the operation of the driver, the current driving state is notified to the driver.

  Next, the traveling control device 100 that is the center of the traveling control system 1 will be described. The travel control device 100 generates a target route on which the host vehicle travels based on the recognition result of the external environment by the external environment recognition device 10, the host vehicle position information and the traffic information from the positioning device 20 and the map information processing device 30. The travel control via the engine control device 40, the transmission control device 50, the brake control device 60, and the steering control device 70 is executed so as to follow the target route.

  In the follow-up traveling control to the target route, the traveling control device 100 determines the state of the disturbance generated in front of the own vehicle from the change in the traveling state of the other vehicle in front of the own vehicle, and adds to the own vehicle from now on. Predict possible disturbances. When a sudden disturbance to the host vehicle is predicted, the control gain of the steering amount that causes the traveling locus of the host vehicle to follow the target route is corrected in advance, and the target route is tracked according to the predicted disturbance. Adjust gender.

  As other vehicles in front of the host vehicle, the disturbance applied to the host vehicle is predicted mainly by monitoring the behavior of the preceding vehicle mainly on the preceding vehicle traveling in the same direction along the traveling lane of the host vehicle. Even when no preceding vehicle is detected, the behavior of the oncoming vehicle is monitored if there is an oncoming vehicle traveling forward in the opposite lane adjacent to the traveling lane of the own vehicle toward the own vehicle. By doing so, it is possible to predict a disturbance to be applied to the vehicle from now on.

  For this reason, the travel control device 100 includes a target route generation unit 101, a target steering angle setting unit 102, a disturbance prediction unit 103, a follow-up control gain correction unit 104, and a control unit 105 as functional units related to the follow-up travel control to the target route. It has. With these function units, the running state of the host vehicle is adjusted in advance in preparation for disturbances to be applied to the host vehicle, and the effect of the actual disturbance on the host vehicle is alleviated to maintain stable and smooth driving. It becomes possible to do.

  Specifically, the target route generation unit 101 calculates the trajectory of the target point that is the target of the vehicle's follow-up travel based on the recognition result of the external environment by the external environment recognition device 10 and high-definition map data. The trajectory of the target point is set as the target route. For example, as shown in FIG. 2, the target point that is the target of the follow-up travel is set at the lane center position in the road width direction of the left and right white lines as lane markings so that the travel position of the host vehicle is at the lane center. To be controlled.

  Here, an example will be described in which a route whose target point is the center position in the road width direction of the left and right white lines recognized from the captured image of the camera unit 11 is identified as a target route by a secondary approximate curve. When generating a target route based on white line information, white line candidate points detected on the image are 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 detected on the image are combined with the past white line data estimated based on the movement amount of the host vehicle, and a quadratic method, for example, is applied to these data point groups by applying the least square method. The locus of white line candidate points expressed by a curve is obtained. The locus of the white line candidate point is obtained as a left and right curve corresponding to the left and right white lines, and the locus of the center position obtained from the left and right curves is set as the target route, as shown by the following equation (1).
X = A · Z ² + B · Z + C (1)

  Here, in the equation (1), coefficients A, B, and C represent path components constituting the target path. The coefficient A represents the curvature component of the target route, the coefficient B is the yaw angle component of the target route with respect to the host vehicle (the angle component between the longitudinal axis of the host vehicle and the target route (tangent)), and the coefficient C is the target vehicle. This represents a position component (lateral position component) in the horizontal direction (X-axis direction) of the target route.

The target steering angle setting unit 102 sets a target steering angle αref for follow-up control that matches the center position of the host vehicle in the vehicle width direction with the target point on the target route. The target steering angle αref to the target route is, as shown in the following equation (2), a feed-forward (FF) control steering angle αff for tracing the route corresponding to the curvature κ of the target route, and the target route Is calculated by adding the lateral position deviation of the host vehicle with respect to and the steering angle αfb of feedback control for eliminating the yaw angle deviation of the host vehicle with respect to the target route.
αref = αff + αfb (2)

In detail, the steering angle αff of the feedforward control is calculated by multiplying the curvature κ of the target route by predetermined coefficients Gff and Dh, for example, by the following equation (3).
αff = Dh · Gff · κ (3)

  For example, as shown in FIG. 2, the curvature κ in the equation (3) can be obtained by applying the value of the coefficient A when the target route is approximated by a quadratic equation represented by the equation (1). The coefficient Gff in the equation (3) is a gain in the feedforward control, and a map is created by obtaining an optimum gain corresponding to the curvature κ by experiments and simulations in advance, and is set with reference to this map. .

  Further, the coefficient Dh in the expression (3) is a correction coefficient set by the follow-up control gain correction unit 104, and is normally set to Dh = 1.0, and the gain Gff is set as a map value. As will be described later, when a disturbance is expected to be applied to the host vehicle after a predetermined time, Dh> 1.0 or Dh <1.0 is set, and the gain Gff of the map setting is corrected to return to the target route. The followability, that is, the convergence of the traveling track of the host vehicle to the target route is adjusted.

On the other hand, the steering angle αfb of the feedback control is a lateral position with respect to the target route of the host vehicle at a predetermined distance ZL when traveling at the current steering angle, as shown in the following equations (4-1) to (4-4). Proportional control term αp for deviation δ ′ (see FIG. 2), integral control term αi of lateral position deviation δ (see FIG. 2) relative to the target route of the host vehicle, and yaw angle deviation θy relative to the target route of the host vehicle (see FIG. 2) Is a steering angle including a proportional control term αy with respect to and a differential control term αr of the yaw angle deviation θy with respect to the target route of the host vehicle, and these control terms αp, αi, αy, αr as shown in the following equation (5) Is set as the steering angle.
αp = Gp · δ ′ (4-1)
αi = Gi · ∫δdt (4-2)
αy = Gy · θy (4-3)
αr = Gr · dθy / dt (4-4)
αfb = αp + αi + αy + αr
= Gp · δ ′ + Gi · ∫δdt + Gy · θy + Gr · dθy / dt (5)
Gp: Proportional gain for lateral position deviation
Gi: Integral gain for lateral position deviation
Gy: Proportional gain for yaw angle deviation
Gr: Differential gain with respect to yaw angle deviation

  Here, the proportional control term αp shown in the equation (4-1) is a control term for setting the deviation to 0 in proportion to the deviation of the lateral position between the target route and the host vehicle. This proportional control term αp is calculated by multiplying the lateral position deviation δ ′ by a proportional gain Gp.

  The lateral position deviation δ ′ is estimated (or detected by a sensor) from the vehicle's lateral position at a predetermined distance when traveling at the current steering angle from the vehicle speed, vehicle-specific stability factor, wheelbase, steering gear ratio, etc. Calculated from the yaw rate of the host vehicle) and obtained as a deviation between the estimated lateral position of the host vehicle and the lateral position of the target path ahead. The lateral position of the target route can be obtained by applying the value of the coefficient C, for example, when the target route is approximated by a quadratic expression represented by the equation (1).

  Note that the proportional control term αp may be a control term proportional to the current lateral position deviation δ with respect to the target route of the host vehicle, depending on conditions such as the type of tracking target and the traveling speed. The control term may include both a proportional control amount and a control amount proportional to the lateral position deviation δ ′.

  The integral control term αi shown in the equation (4-2) is the difference between the target value and the target value due to a disturbance that occurs constantly between the output of the proportional control and the target value, or a disturbance such as a crosswind or a road surface crossing gradient (kant). It compensates for the deviation that occurs in the meantime, and prevents the vehicle from traveling offset from the target route. The integral control term αi is calculated by multiplying an integral value obtained by integrating the lateral position deviation δ by a predetermined integral gain Gi.

  The proportional control term αy shown in the equation (4-3) is a control term for feedback control of the yaw angle of the host vehicle to the yaw angle along the target route, and the yaw angle deviation θy is multiplied by the proportional gain Gy. Calculated. The yaw angle deviation θy can be obtained by applying the value of the coefficient B, for example, when the target path is approximated by a quadratic expression represented by the expression (1). The differential control term αr shown in the equation (4-4) is a control term for converging the yaw angle of the host vehicle to the yaw angle along the target route with good responsiveness, and the differential gain Gr is added to the yaw angle deviation θy. It is calculated by multiplying.

  The disturbance predicting unit 103 determines the state of disturbance in front of the host vehicle due to crosswinds, road dredging, etc., from changes in the behavior of other vehicles in front of the host vehicle such as a preceding vehicle traveling in front of the host vehicle or an oncoming vehicle traveling in the opposite lane. Estimate and predict the disturbance that will be applied to the vehicle. As the behavior change of the preceding vehicle or the oncoming vehicle, the variation amount of the lateral position in the lane width direction is detected.

  The lateral position of the preceding vehicle or the oncoming vehicle can be calculated based on the image captured by the camera unit 11 as with the lateral position of the host vehicle with respect to the target route, and is calculated as, for example, a deviation from the lane center position. Then, the deviation of the preceding vehicle and the oncoming vehicle from the lane center position is sampled over a predetermined time, and the change amount of the lateral position with respect to the average value of the obtained time series data is calculated as the lateral position fluctuation amount.

  The disturbance prediction unit 103 determines that the lateral position fluctuation amount of the other vehicle ahead deviates from the lateral position fluctuation amount of the host vehicle by a predetermined set value or more, and the lateral position fluctuation amount of the other vehicle has a predetermined threshold value. If it exceeds, it is determined that a sudden disturbance has occurred in front of the host vehicle due to crosswinds or road dredging. Then, it is predicted that a disturbance will act on the host vehicle when the host vehicle passes through the position after a predetermined time, and an instruction to correct the control gain of the target steering angle αref is output to the follow-up control gain correction unit 104. .

  Here, as shown in FIG. 3, a description will be given by taking as an example a disturbance caused by the cross wind W blowing through between the buildings D1 and D2 adjacent to each other along the road RD at a predetermined interval. FIG. 3 illustrates a situation in which no oncoming vehicle is detected in the oncoming lane P2 adjacent to the traveling lane P1 of the host vehicle CR1, and only the preceding vehicle CR2 is detected in front of the own vehicle CR1 on the running lane P1.

  In such a situation, when the preceding vehicle CR2 passes between the building D1 and the building D2 from the side of the building D1, it receives the cross wind W and fluctuates, and the lateral position in the lane changes. As shown in FIG. 4, the lateral position variation Δδ2 of the preceding vehicle CR2 becomes the maximum in the time zone passing between the building D1 and the building D2, and then converges toward the original lateral position. Go.

  Therefore, the disturbance predicting unit 103 estimates the state of the disturbance suddenly generated in front of the own vehicle by monitoring the lateral position fluctuation amount Δδ2 of the preceding vehicle CR2 and comparing it with the lateral position fluctuation amount of the own vehicle. A disturbance acting on the host vehicle after a predetermined time can be predicted. When there is a road dredge ahead of the host vehicle, the occurrence of disturbance can be estimated in the same manner by the fluctuation of the lateral position of the preceding vehicle CR2, but the fluctuation of the lateral position due to the road dredge is caused by the fluctuation of the lateral position due to the crosswind. The fluctuation time is relatively long.

  Further, FIG. 5 shows that the preceding vehicle CR2 is detected in the traveling lane P1, the oncoming vehicle CR3 is detected in the oncoming lane P2, and the building D1 and the building D2 are almost simultaneously in the preceding vehicle CR2 and the oncoming vehicle CR3. It shows the situation of passing between. In FIG. 5, since the cross wind W blows in from the oncoming vehicle side, the preceding vehicle CR2 and the oncoming vehicle CR3 are simultaneously affected by the cross wind W, and the lateral position varies in the same direction.

  In this case, as shown in FIG. 6, the lateral position variation Δδ2 of the preceding vehicle CR2 is slightly smaller than the lateral position variation Δδ3 of the oncoming vehicle CR3, but the same behavioral change occurs almost at the same time. Therefore, the disturbance predicting unit 103 can predict that the preceding vehicle CR2 and the oncoming vehicle CR3 are subjected to a disturbance due to a cross wind or the like from the same direction, and that the disturbance also acts on the host vehicle at a predetermined forward position. Moreover, since the disturbance is determined from the behavior change of both the preceding vehicle and the oncoming vehicle as compared with the case of only the preceding vehicle, the disturbance can be predicted with higher reliability.

  In the case where the fluctuation direction of the lateral position of the preceding vehicle differs from that of the oncoming vehicle, or when the lateral position of the oncoming vehicle does not vary even if the lateral position of the preceding vehicle changes, a disturbance other than the side wind, for example, the own vehicle It can be presumed that the disturbance is caused by dredging of the road on the side of the traveling lane. If the lateral position of the preceding vehicle does not change and the lateral position of the oncoming vehicle changes, consider the factors such as the positional relationship between the preceding vehicle and the oncoming vehicle, the direction of change, and the traveling environment ahead of the host vehicle. It can be determined whether the disturbance has an influence on the traveling of the host vehicle.

  On the other hand, as shown in FIG. 7, the preceding vehicle CR2 is detected in the traveling lane P1, and the oncoming vehicle CR3 is detected in the oncoming lane P2, but the buildings D3 are continuously arranged on the side of the road RD. In the case where the cross wind W from the gap between the building D1 and the building D2 does not occur, the preceding vehicle CR2 and the oncoming vehicle CR3 do not fluctuate unless particularly abnormal. That is, as shown in FIG. 8, the lateral position fluctuation amount Δδ2 of the preceding vehicle CR2 and the lateral position fluctuation amount Δδ3 of the oncoming vehicle CR3 are within the range of normal travel, although there are some fluctuations.

  In this way, the disturbance prediction unit 103 can determine whether a driver's operation of one of the vehicles or a disturbance such as a cross wind is by monitoring a change in the behavior of another vehicle in front of the host vehicle such as a preceding vehicle or an oncoming vehicle. . In the present embodiment, the disturbance predicting unit 103 is configured to drive forward when the lateral position fluctuation amount of the other vehicle deviates from the lateral position fluctuation amount of the own vehicle by a predetermined value or more and exceeds a predetermined threshold. It is determined that there is a disturbance that affects Then, an instruction for correcting the control gain of the target steering angle αref is output to the follow-up control gain correction unit 104 in order to deal with disturbance in front of the host vehicle.

  In this case, if it is determined that the external environment recognition device 10 recognizes the driving environment outside the host vehicle and the lateral position fluctuation amount of the other vehicle as a disturbance caused by drought due to snow accumulation, In this way, the control gain of the target steering angle αref is not corrected in a direction that increases the followability to the target route, but is corrected in a direction that weakens the followability to the target route. As a result, it becomes possible to avoid the interference with the kite and drive the vehicle following the kite.

  In the present embodiment, the disturbance determination threshold for the lateral position variation amount is set according to the recognized vehicle height, for example, a disturbance determination threshold δH for a vehicle with a high vehicle height and a vehicle with a low vehicle height. Is set in two stages with respect to the disturbance determination threshold value δL. Usually, a vehicle with a higher vehicle height is more susceptible to disturbances, and therefore, ΔH> ΔL is set. The height of the vehicle may be divided into two stages of H higher than the set value and L lower than the set value. However, by comparing the relative height with the host vehicle, H (high) and L ( (Low) may be classified.

  The follow-up control gain correction unit 104 corrects the control gain of the target steering angle αref when the disturbance prediction unit 103 predicts that a disturbance will be applied to the host vehicle after a predetermined time and is instructed to correct the control gain of the target steering angle αref. To do. In the present embodiment, the gain Gff of the feedforward control with respect to the curvature of the target route is corrected as the control gain of the target steering angle αref. Therefore, the follow-up control gain correction unit 104 sets the correction coefficient Dh in the above-described equation (3) to Dh> 1.0 or Dh <1.0 and outputs it to the target steering angle setting unit 102 for map setting. The gain Gff is corrected.

  In the present embodiment, the gain Gff at the steering angle αff of the feedforward control is targeted for correction as the control gain of the target steering angle αref, but the gains Gp, Gi, Gy, Gr may be corrected as appropriate. For example, the gain Gff of the feedforward control may be corrected, and the differential gain of the yaw angle deviation θy with respect to the target path may be corrected in advance so as to adjust the follow-up response to the target path during disturbance action.

The control unit 105 calculates a deviation Δα (Δα = αref−αr) between the target steering angle αref set by the target steering angle setting unit 102 and the actual steering angle αr detected by the steering angle sensor or the like. As shown in equations (1), (6-2), and (6-3), the proportional control steering torque Tp, the differential control steering torque Td, and the integral control steering torque Ti are calculated.
Tp = Kp · Δα (6-1)
Td = Kd · dΔα / dt (6-2)
Ti = Ki∫Δαdt (6-3)

Then, as shown in the following equation (7), these steering torques Tp, Td, Ti are added together, and a target for matching the actual steering angle αr with the target steering angle αref by feedback control based on the steering angle deviation Δα. A steering torque Tfb is calculated. This target steering torque Tfb is output to the steering control device 70 and executed as current control of the electric power steering motor. When there is no override by the driver's steering operation, the proportional gain Kp optimally set in advance through experiments, simulations, etc. The drive current of the electric power steering motor is controlled by PID control using the differential gain Kd and the integral gain Ki.
Tfb = Tp + Ti + Td
= Kp · Δα + Kd · dΔα / dt + Ki · ∫Δαdt (7)

  At this time, if it is predicted that a disturbance will act on the host vehicle at a predetermined forward position based on fluctuations in the traveling state of both or one of the preceding vehicle and the oncoming vehicle, the target steering is performed before reaching the corresponding position. Since the control gain of the angle αref is corrected in advance, the influence on the vehicle behavior when a disturbance is actually applied can be reduced, and stable traveling can be realized.

  Next, travel control program processing by the above functional units will be described with reference to the flowcharts shown in FIGS. The travel control process shown in the flowchart of FIG. 9 is a main process of the travel control, and the target steering angle setting process shown in the flowchart of FIG. 10 is a sub-process in the travel control process.

  The travel control device 100 reads the recognition result of the external environment by the external environment recognition device 10 in the first step S1 of the main processing of the travel control, and determines whether there is a preceding vehicle ahead of the host vehicle (whether it is detected). ) If there is no preceding vehicle, the process proceeds to step S2 and subsequent steps. If the preceding vehicle is present, the process proceeds to step S10 and subsequent steps.

  In the case where there is no preceding vehicle, in step S2, it is further checked whether or not there is an oncoming vehicle. In the case where there is no oncoming vehicle, a mode (including a mode without correction) for correcting the control gain of the target steering angle in step S3. The flag FLG shown is set. The flag FLG stores the presence / absence of the preceding vehicle, the height of the preceding vehicle, the presence / absence of the oncoming vehicle, and the height of the oncoming vehicle for each bit of the bit field, for example.

  After setting the flag FLG in step S3 so that there is no preceding vehicle or oncoming vehicle, the process proceeds to step S4, where the target steering angle setting process shown in FIG. 10 is executed as a sub-process to determine the target steering angle αref. Next, the process proceeds from step S4 to step S20, and steering control is performed via the steering control device 70 so that the actual steering angle αr matches the target steering angle αref. By this steering control, the electric power steering motor is driven with a target steering torque Tfb that matches the actual steering angle αr with the target steering angle αref.

  Here, the sub-process for setting the target steering angle in FIG. 10 will be described. In the first step S101 of the target steering angle setting process, the travel control device 100 refers to the value of the flag FLG, reads information on the presence / absence of a preceding vehicle, the presence / absence of an oncoming vehicle, and the height of the vehicle, and faces the preceding vehicle. It is checked whether at least one of the vehicle and the vehicle is detected. If neither the preceding vehicle nor the oncoming vehicle is detected, the process proceeds from step S101 to step S106, the control gain of the target steering angle is not corrected, and the target steering angle αref is set in step S107.

  In the target steering angle setting sub-process executed in step S4 of the travel control process, neither the preceding vehicle nor the oncoming vehicle is detected. Therefore, the normal target steering angle αref corresponding to the disturbance detected from the behavior of the host vehicle is obtained. Will be set. The control gain at this time is set to no gain correction because the follow-up control gain correction unit 104 sets the correction coefficient Dh in the above equation (3) to Dh = 1.0.

  Then, in the target steering angle setting unit 102, the target steering is performed by the feed-forward control steering angle αff by the map setting gain Gff corresponding to the curvature κ of the target route and the feedback control steering angle αfb expressed by the equation (5). The angle αref is set. In the steering control based on the target steering angle αref, disturbances caused by the current cross wind and the road surface crossing gradient (cant) are compensated by the integral control term αi at the steering angle αfb.

  On the other hand, if both or one of the preceding vehicle and the oncoming vehicle is detected in step S101, the process proceeds from step S101 to step S102, and the lateral position variation amount in the X-axis direction (lane width direction) of the corresponding vehicle. Calculate Further, in step S103, a disturbance determination threshold for the lateral position fluctuation amount of the corresponding vehicle is set according to the height of the corresponding vehicle. As described above, in this embodiment, the threshold value δH is set when the vehicle height is high, and the threshold value δL is set when the vehicle height is low (δH> δL).

  Thereafter, in step S104, it is checked whether or not the lateral position fluctuation amount is equal to or greater than a threshold value. If the lateral position fluctuation amount is less than the threshold value, it is determined that there is no particular disturbance ahead of the host vehicle, the process proceeds from step S104 to step S106 described above, and the control gain of the target steering angle is not corrected. In step S107 described above, A normal target steering angle αref is set. On the other hand, if the lateral position fluctuation amount is greater than or equal to the threshold value, the process proceeds from step S104 to step S105, where the correction amount of the control gain of the target steering angle corresponding to the disturbance ahead of the host vehicle is set. The target steering angle αref is set with the control gain that has been prepared and corrected.

  Next, when returning to the main process of travel control, if there is an oncoming vehicle in step S2, the process proceeds from step S2 to step S5, and the vehicle height of the oncoming vehicle is compared with a set value to check whether it is H (high). . If the vehicle height of the oncoming vehicle is H, the flag FLG is set to the vehicle height H (high) of the oncoming vehicle without the preceding vehicle, the oncoming vehicle, and the oncoming vehicle at step S6, and the vehicle height of the oncoming vehicle is L (low). In this case, in step S7, the flag FLG is set to the absence of the preceding vehicle, the presence of the oncoming vehicle, and the vehicle height L (low) of the oncoming vehicle.

  Thereafter, the process proceeds to step S8, where the state of disturbance is detected from the relative behavior of the oncoming vehicle with respect to the host vehicle, the target steering angle αref is set by the sub-processing of the target steering angle setting in FIG. 10, and the steering control is performed in step S20. Do. For example, when the own vehicle and the oncoming vehicle in front of the own vehicle cause lateral position fluctuations in the same direction, and the lateral position fluctuation amount of the oncoming vehicle and the lateral position fluctuation amount of the own vehicle are less than a set value, As a result, the steering control is performed at the target steering angle corresponding to the current disturbance without correcting the control gain in preparation for a sudden disturbance in the forward direction. carry out.

  On the other hand, when the lateral position fluctuation amount of the oncoming vehicle and the lateral position fluctuation amount of the host vehicle are more than the set value and are greater than or equal to the disturbance determination threshold (threshold value δH or δL), the disturbance is The control gain of the target steering angle is corrected by judging that the vehicle is suddenly applied to the front position, and prepares for a sudden disturbance at the front position. If the target steering angle αref at this time is determined to be a disturbance due to a crosswind, the correction coefficient Dh in the above-described equation (3) is set to Dh> 1.0, and the feedforward control gain Gff is set to a target higher than usual. Correct the direction to increase the followability to the route. If it is determined that the disturbance is caused by road dredging, the correction coefficient Dh is set to Dh <1.0, and the gain Gff of the feedforward control is corrected so as to significantly weaken the followability to the target route than usual. , Enabling travel that follows the habit.

  On the other hand, if there is a preceding vehicle in the first step S1, the process proceeds from step S1 to step S10, and the vehicle height of the preceding vehicle is compared with a set value to check whether it is H (high). If the vehicle height of the preceding vehicle is H, in step S11, the preceding vehicle is present, the flag FLG is set to the vehicle height H (high) of the preceding vehicle, and the process proceeds to step S13. If the vehicle height of the preceding vehicle is L (low), the flag FLG is set to the vehicle height L (low) of the preceding vehicle in step S12, and the process proceeds to step S13.

  In step S13, it is checked whether or not there is an oncoming vehicle. If there is no oncoming vehicle, the process proceeds to step S14, where information on the absence of the oncoming vehicle is added to the flag FLG, and the process proceeds to step S15. In step S15, a disturbance is detected from the relative behavior of the preceding vehicle with respect to the host vehicle, the target steering angle αref is set by the sub-processing for setting the target steering angle in FIG. 10, and steering control is performed in step S20. Since the target steering angle αref at this time is a mode with a preceding vehicle and without an oncoming vehicle, a disturbance in front of the own vehicle is predicted based only on the relative behavior of the preceding vehicle with respect to the own vehicle, and the target vehicle is suddenly moved forward. When it is predicted that a disturbance will be applied, the gain Gff of the feedforward control at the target steering angle is corrected by the correction coefficient Dh as in step S8 described above.

  On the other hand, if there is an oncoming vehicle in step S13, the process proceeds from step S13 to step S16, and the vehicle height of the oncoming vehicle is compared with a set value to check whether it is H (high). If the vehicle height of the oncoming vehicle is H, the flag FLG is set in step S17 to the presence of the preceding vehicle, the vehicle height H or L of the preceding vehicle, the oncoming vehicle, and the vehicle height H of the oncoming vehicle. When the height is L, in step S18, the flag FLG is set to the preceding vehicle present, the vehicle height H or L of the preceding vehicle, and the vehicle height L of the oncoming vehicle.

  After the flag FLG is set in step S17 or step S18, the process proceeds to step S19, where a disturbance is detected from the relative behavior of the preceding vehicle and the oncoming vehicle with respect to the host vehicle, and the target steering angle setting sub-process in FIG. Set the target steering angle αref. Then, the process proceeds from step S19 to step S20, and steering control is performed.

  Since the target steering angle αref in step S19 is a mode in which both the preceding vehicle and the preceding vehicle are present, the state of disturbance is compared with the mode of only the oncoming vehicle in step S8 or the mode of only the preceding vehicle in step S15. It can be judged with higher reliability. Therefore, when the gain Gff of the feedforward control is corrected in step S19, the correction amount of the gain Gff can be made larger than in steps S8 and S15.

  For example, compared to a case where a sudden disturbance due to a cross wind is predicted from the lateral position fluctuation amount of one of the preceding vehicle and the oncoming vehicle, and the gain Gff of the feedforward control is corrected with Dh = 1.1, the preceding vehicle When a sudden disturbance due to cross wind is predicted from the lateral position fluctuation amounts of both the vehicle and the oncoming vehicle, the gain Gff of the feed forward control is set so that Dh = 1.2 and the followability to the target route becomes stronger. Correct.

  As described above, in the present embodiment, the state of the disturbance occurring in front of the host vehicle is determined from the behavior change of the other vehicle in front of the host vehicle, and the disturbance applied to the vehicle is predicted. When a disturbance to the host vehicle is predicted, the control gain of the steering amount that causes the traveling locus of the host vehicle to follow the target route is corrected, and the traveling state of the host vehicle is adjusted in advance in preparation for the disturbance. Thereby, it is possible to reduce the influence when a disturbance is actually applied to the host vehicle and maintain a stable and smooth running, and to give the driver a driving feeling without a sense of incongruity.

DESCRIPTION OF SYMBOLS 1 Travel control system 10 External environment recognition apparatus 70 Steering control apparatus 100 Travel control apparatus 101 Target route generation part 102 Target steering angle setting part 103 Disturbance prediction part 104 Follow-up control gain correction part 105 Control part alpharef Target steering angle Gff Feedforward control Gain Dh correction factor

Claims (6)

A travel control device for a vehicle that generates a target route on which the host vehicle travels and controls follow-up travel to the target route,
A disturbance prediction unit that predicts a disturbance applied to the host vehicle based on a behavior change of the other vehicle in front of the host vehicle;
A follow-up control gain correction unit that corrects a control gain of a target steering angle that causes the traveling locus of the host vehicle to follow the target path when the disturbance prediction unit predicts that a disturbance is applied to the host vehicle;
A vehicle travel control device comprising:   2. The vehicle travel according to claim 1, wherein the other vehicle includes not only a preceding vehicle traveling in the same direction in front of the host vehicle but also an oncoming vehicle traveling from the front of the host vehicle toward the host vehicle. Control device.   The disturbance predicting unit predicts that a disturbance is applied to the own vehicle when the lateral position fluctuation amount is equal to or greater than a determination threshold, with the behavior change of the other vehicle ahead of the own vehicle as a lateral position fluctuation amount in a lane. The travel control device for a vehicle according to claim 1 or 2.   The vehicle disturbance control device according to any one of claims 1 to 3, wherein the disturbance prediction unit sets the determination threshold according to a vehicle height of the other vehicle ahead of the host vehicle.   The follow-up control gain correction unit corrects the control gain of the target steering angle in a direction that enhances the follow-up performance of the host vehicle to the target route. Vehicle travel control device.   6. The vehicle travel control apparatus according to claim 1, wherein the control gain of the target steering angle is a gain of feedforward control with respect to a curvature of the target route.

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