Patent Publication Number: US-2022234576-A1

Title: Travel control apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese Patent Applications No. 2021-009538 filed on Jan. 25, 2021 and No. 2021-203418 filed on Dec. 15, 2021, the content of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates to a travel control apparatus configured to a correct driving path a vehicle according to surrounding situation of the vehicle. 
     Description of the Related Art 
     As this type of apparatus, there has been known a conventional apparatus that corrects a steering angle in a direction away from the other vehicle when recognizing approach of the other vehicle traveling in a lane adjacent to a lane in which the vehicle is traveling (for example, JP 2014-129021 A). 
     However, if a driving path is simply corrected in a direction away from the other vehicle as in the apparatus disclosed in JP 2014-129021 A, an occupant may feel uncomfortable depending on a situation around the subject vehicle such as when the other vehicle is present in the direction. 
     SUMMARY OF THE INVENTION 
     An aspect of the present invention is a travel control apparatus including a microprocessor and a memory connected to the microprocessor. The microprocessor is configured to perform: recognizing a surrounding situation of a subject vehicle; generating a target path of the subject vehicle according to the surrounding situation recognized in the recognizing; calculating a correction amount for correcting the target path generated in the generating in a direction away from a first other vehicle in a vehicle width direction, the first other vehicle traveling in a first adjacent lane in which a traveling direction is the same as a traveling direction of a subject lane on which the subject vehicle travels and which is adjacent to one side of the subject lane, when the first other vehicle is recognized in the recognizing and the subject vehicle is predicted to pass a side of the first other vehicle or the first other vehicle is predicted to pass a side of the subject vehicle; when a second other vehicle traveling in a second adjacent lane which is adjacent to another side of the subject lane is recognized in the recognizing, determining whether to correct the target path based on a traveling situation of the second other vehicle; and correcting the target path based on the correction amount calculated in the calculating when the target path is determined to be corrected in the determining. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objects, features, and advantages of the present invention will become clearer from the following description of embodiments in relation to the attached drawings, in which: 
         FIG. 1  is a block diagram schematically illustrating an overall configuration of a vehicle control system according to an embodiment of the present invention; 
         FIG. 2A  is a diagram illustrating an example of a road situation; 
         FIG. 2B  is a diagram illustrating another example of a road situation; 
         FIG. 3  is a block diagram illustrating a main part configuration of a travel control apparatus according to an embodiment of the present invention; 
         FIG. 4  is a diagram illustrating an example of a determination area; 
         FIG. 5A  is a diagram illustrating an example of a positional relationship between vehicles; 
         FIG. 5B  is a diagram illustrating an example of a positional relationship between vehicles at a time point after  FIG. 5A ; 
         FIG. 5C  is a diagram illustrating an example of a positional relationship between vehicles at a time point after  FIG. 5B ; 
         FIG. 5D  is a diagram illustrating an example of a positional relationship between vehicles at a time point after  FIG. 5C ; 
         FIG. 6  is a flowchart showing an example of processing executed by the CPU of the controller in  FIG. 3 ; 
         FIG. 7A  is a diagram illustrating another example of a road situation; 
         FIG. 7B  is a diagram illustrating another example of a road situation; 
         FIG. 8  is a diagram illustrating an example of a road at which a separation zone is not provided; 
         FIG. 9  is a diagram illustrating an example of a determination area according to a modification of the embodiment of the present invention; and 
         FIG. 10  is a diagram illustrating an example of a scene where another vehicle passes a side of the vehicle. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An embodiment of the present invention will be described below with reference to  FIGS. 1 to 10 . A travel control apparatus according to the embodiment of the present invention can be applied to a vehicle having a driving support function or a self-driving capability. An example in which the travel control apparatus is applied to a vehicle (self-driving vehicle) having a self-driving capability will be described below. A vehicle to which the travel control apparatus according to the present embodiment is applied may be referred to as a subject vehicle to be distinguished from other vehicles. The subject vehicle can travel not only in a self-drive mode in which a driving operation by a driver is unnecessary, but also in a manual drive mode by the driving operation by the driver. 
       FIG. 1  is a block diagram schematically illustrating an overall configuration of a vehicle control system (vehicle control apparatus)  10  that controls a subject vehicle. As illustrated in  FIG. 1 , the vehicle control apparatus  10  mainly includes a controller  40 , an external sensor group  31 , an internal sensor group  32 , an input/output device  33 , a positioning sensor  34 , a map database  35 , a navigation unit  36 , a communication unit  37 , and a traveling actuator (hereinafter, simply referred to as an actuator) AC each electrically connected to the controller  40 . 
     The external sensor group  31  is a generic term for a plurality of sensors that detect an external situation which is peripheral information of the subject vehicle. For example, the external sensor group  31  includes a LiDAR that measures scattered light with respect to irradiation light in all directions of the subject vehicle and measures a distance from the subject vehicle to surrounding obstacles, and a radar that detects other vehicles, obstacles, and the like around the subject vehicle by irradiating with electromagnetic waves and detecting reflected waves. Furthermore, for example, the external sensor group  31  includes a camera that is mounted on the subject vehicle, has an imaging element such as a CCD or a CMOS, and images a periphery (forward, backward and sideward) of the subject vehicle, a microphone that inputs a signal of sound from the periphery of the subject vehicle (hereinafter, simply referred to as a microphone), and the like. A signal detected by the external sensor group  31  and a signal input to the external sensor group  31  are transmitted to the controller  40 . 
     The internal sensor group  32  is a generic term for a plurality of sensors that detect a traveling state of the subject vehicle and a state inside the vehicle. For example, the internal sensor group  32  includes a vehicle speed sensor that detects a vehicle speed of the subject vehicle, an acceleration sensor that detects an acceleration in a front-rear direction of the subject vehicle and an acceleration in a left-right direction (lateral acceleration) of the subject vehicle, a rotation speed sensor that detects the rotation speed of a traveling drive source, a yaw rate sensor that detects a rotation angular speed around a vertical axis of the center of gravity of the subject vehicle, and the like. The internal sensor group  32  further includes a sensor that detects driver&#39;s driving operation in a manual drive mode, for example, operation of an accelerator pedal, operation of a brake pedal, operation of a steering wheel, and the like. A detection signal from the internal sensor group  32  is transmitted to the controller  40 . 
     The input/output device  33  is a generic term for devices in which a command is input from a driver or information is output to the driver. For example, the input/output device  33  includes various switches to which the driver inputs various commands by operating an operation member, a microphone to which the driver inputs a command by voice, a display that provides information to the driver via a display image, a speaker that provides information to the driver by voice, and the like. The various switches include a manual automatic changeover switch (SW) that instructs either a self-drive mode or a manual drive mode. 
     The manual automatic changeover switch is configured as, for example, a switch manually operable by a driver, and outputs a changeover command to the self-drive mode in which a self-driving capability is enabled or the manual drive mode in which the self-driving capability is disabled according to a switch operation. Switching from the manual drive mode to the self-drive mode or switching from the self-drive mode to the manual drive mode can be instructed when a predetermined traveling condition is satisfied regardless of operation of the manual automatic changeover switch. That is, by automatically switching the manual automatic changeover switch, the mode can be automatically switched instead of manually switching. 
     The positioning sensor  34  is, for example, a GPS sensor, receives a positioning signal transmitted from a GPS satellite, and measures an absolute position (latitude, longitude, and the like) of the subject vehicle based on the received signal. The positioning sensor  34  includes not only the GPS sensor but also a sensor that performs positioning using radio waves transmitted from a quasi-zenith orbit satellite. A signal (a signal indicating a measurement result) from the positioning sensor  34  is transmitted to the controller  40 . 
     The map database  35  is a device that stores general map information used for the navigation unit  36 , and is constituted of, for example, a hard disk. The map information includes road position information, information on a road shape (curvature or the like), and position information on intersections and branch points. The map information stored in the map database  35  is different from highly accurate map information stored in a memory unit  42  of the controller  40 . 
     The navigation unit  36  is a device that searches for a target route on a road to a destination input by a driver and provides guidance along the target route. The input of the destination and the guidance along the target route are performed via the input/output device  33 . The target route is calculated based on a current position of the subject vehicle measured by the positioning sensor  34  and the map information stored in the map database  35 . 
     The communication unit  37  communicates with various servers not illustrated via a network including a wireless communication network such as an Internet line, and acquires the map information, traffic information, and the like from the server periodically or at an arbitrary timing. The acquired map information is output to the map database  35  and the memory unit  42 , and the map information is updated. The acquired traffic information includes traffic congestion information and traffic light information such as a remaining time until a traffic light changes from red to green. 
     The actuator AC is a device for operating various devices related to traveling operation of the subject vehicle. The actuator AC includes a brake actuator that operates the braking device, a steering actuator that drives the steering device, and the like. The actuator AC is a traveling actuator for controlling traveling of the subject vehicle. In a case where the traveling drive source is an engine, the actuator AC includes a throttle actuator that adjusts an opening (throttle opening) of a throttle valve of the engine. In a case where the traveling drive source is a traveling motor, the actuator AC includes the traveling motor. The actuator AC also includes a brake actuator that operates a braking device of the subject vehicle and a steering actuator that drives a steering device. 
     The controller  40  includes an electronic control unit (ECU). Although a plurality of ECUs having different functions such as an engine control ECU and a transmission control ECU can be separately provided, in  FIG. 1 , the controller  40  is illustrated as a set of these ECUs for convenience. The controller  40  includes a computer including a processing unit  41  such as a CPU (microprocessor), a memory unit  42  such as a ROM, a RAM, and a hard disk drive, and other peripheral circuits (not illustrated). 
     The memory unit  42  stores highly accurate detailed map information including information on a center position of a lane, information on a boundary of a lane position, and the like. More specifically, road information, traffic regulation information, address information, facility information, telephone number information, and other information are stored as the map information. The road information includes information indicating the type of road such as a highway, a toll road, and a national highway, and information such as the number of lanes of a road, the width of each lane, a road gradient, a three-dimensional coordinate position of the road, a curvature of a curve of the lane, positions of the merging point and branch point of the lane, a road sign, and the presence or absence of a median strip. The traffic regulation information includes information indicating that traveling on a lane is restricted or a road is closed due to construction or the like. The memory unit  42  also stores information such as a shift map (shift diagram) serving as a reference of shift operation, various control programs, and a threshold used in the programs. 
     The processing unit  41  includes a subject vehicle position recognition unit  43 , an exterior environment recognition unit  44 , an action plan generation unit  45 , and a driving control unit  46  as functional configurations related to automatic travel. 
     The subject vehicle position recognition unit  43  recognizes the position (subject vehicle position) of the subject vehicle on a map based on the position information of the subject vehicle received by the positioning sensor  34  and the map information of the map database  35 . The subject vehicle position recognition unit  43  may recognize the subject vehicle position using the map information (information such as the shape of a building) stored in the memory unit  42  and the peripheral information of the subject vehicle detected by the external sensor group  31 , whereby the subject vehicle position can be recognized with high accuracy. For example, the subject vehicle position recognition unit  43  can recognize the subject vehicle position using the map information stored in the memory unit  42  and the image data around the subject vehicle captured by the camera of the external sensor group  31 . When the subject vehicle position can be measured by a sensor installed on the road or outside a road side, the subject vehicle position can be recognized with high accuracy by communicating with the sensor via the communication unit  37 . 
     The exterior environment recognition unit  44  recognizes an external situation around the subject vehicle based on the signal from the external sensor group  31  such as a LiDAR, a radar, and a camera. For example, the exterior environment recognition unit  44  recognizes the position, speed, and acceleration of a surrounding vehicle (a forward vehicle or a rearward vehicle) traveling around the subject vehicle, the position of a surrounding vehicle stopped or parked around the subject vehicle, and the positions and states of other objects. Other objects include signs, traffic lights, road boundaries, road stop lines, buildings, guardrails, utility poles, signboards, pedestrians, bicycles, and the like. The states of other objects include a color of a traffic light (red, green, yellow), the moving speed and direction of a pedestrian or a bicycle, and the like. 
     The action plan generation unit  45  generates a driving path (target path) of the subject vehicle from a current point of time to a predetermined time ahead based on, for example, the target route calculated by the navigation unit  36 , the subject vehicle position recognized by the subject vehicle position recognition unit  43 , and the external situation recognized by the exterior environment recognition unit  44 . When there are a plurality of paths that are candidates for the target path on the target route, the action plan generation unit  45  selects, from among the plurality of paths, an optimal path that satisfies criteria such as compliance with laws and regulations and efficient and safe traveling, and sets the selected path as the target path. Then, the action plan generation unit  45  generates an action plan corresponding to the generated target path. 
     The action plan includes travel plan data set for each unit time Δt from a current point of time to a predetermined time T ahead, that is, travel plan data set in association with a time for each unit time Δt. The travel plan data includes position data of the subject vehicle and vehicle state data for each unit time. The position data is, for example, data of a target point indicating a two-dimensional coordinate position on the road, and the vehicle state data is vehicle speed data indicating the vehicle speed, direction data indicating the direction of the subject vehicle, or the like. The travel plan is updated every unit time. 
     The action plan generation unit  45  generates the target path by connecting the position data for each unit time Δt from the current point of time to the predetermined time T ahead in time order. At this time, the acceleration (target acceleration) for each unit time Δt is calculated based on the vehicle speed (target vehicle speed) of each target point for each unit time Δt on the target path. That is, the action plan generation unit  45  calculates the target vehicle speed and the target acceleration. The target acceleration may be calculated by the driving control unit  46 . 
     When the action plan generation unit  45  generates the target path, the action plan generation unit  45  first determines a travel mode. Specifically, the travel mode is determined, such as following traveling for following a forward vehicle, overtaking traveling for overtaking the forward vehicle, lane change traveling for changing a traveling lane, merging traveling for merging into a main line of a highway or a toll road, lane keeping traveling for keeping the lane so as not to deviate from the traveling lane, constant speed traveling, deceleration traveling, or acceleration traveling. Then, the target path is generated based on the travel mode. 
     In the self-drive mode, the driving control unit  46  controls each of the actuators AC so that the subject vehicle travels along the target path generated by the action plan generation unit  45 . That is, the throttle actuator, the shift actuator, the brake actuator, the steering actuator, and the like are controlled so that the subject vehicle passes through a target point P for each unit time. 
     More specifically, the driving control unit  46  calculates a requested driving force for obtaining the target acceleration for each unit time calculated by the action plan generation unit  45  in consideration of travel resistance determined by a road gradient or the like in the self-drive mode. Then, for example, the actuator AC is feedback controlled so that an actual acceleration detected by the internal sensor group  32  becomes the target acceleration. That is, the actuator AC is controlled so that the subject vehicle travels at the target vehicle speed and the target acceleration. In the manual drive mode, the driving control unit  46  controls each of the actuators AC in accordance with a travel command (accelerator opening or the like) from the driver acquired by the internal sensor group  32 . 
     As illustrated in  FIG. 2A , when the other vehicle  102  is traveling on a lane (adjacent lane) LN 3  adjacent to one side of a lane (traveling lane) LN 2  on which the subject vehicle  101  travels on a road RD of three-lane left-hand traffic on one side, when a relative speed of the subject vehicle  101  with respect to the other vehicle  102  is equal to or higher than a predetermined speed, the subject vehicle  101  passes a side of the other vehicle  102 . At this time, if the distance in the vehicle width direction between the subject vehicle  101  and the other vehicle  102  is not sufficiently secured, the subject vehicle  101  approaches the other vehicle  102  when the subject vehicle  101  passes the side of the other vehicle  102 , and the occupant of the subject vehicle  101  may feel uncomfortable. The lane LN 4  in the drawing is an opposite lane, and a median strip MS is provided between the lane LN 4  and the lane LN 3 . 
     On the other hand, by moving the driving path of the subject vehicle  101  to the left side (the upper side in the drawing) so that the distance in the vehicle width direction between the subject vehicle  101  and the other vehicle  102  is sufficiently secured, the uncomfortable feeling of the occupant as described above can be reduced. However, as illustrated in  FIG. 2B , when the other vehicle  103  is present in the lane (adjacent lane) LN 1  adjacent to the other side of the traveling lane LN 2  of the subject vehicle  101 , if the driving path of the subject vehicle  101  is moved to the left side, the subject vehicle  101  and the other vehicle  103  approach each other, and thus an occupant of the subject vehicle  101  may feel uncomfortable due to the approach. Therefore, in the present embodiment, the travel control apparatus is configured as below so as to reduce the uncomfortable feeling of the occupant due to the approach to the surrounding vehicle when passing the side of the surrounding vehicle. 
       FIG. 3  is a block diagram illustrating a main part configuration of a travel control apparatus  200  according to the embodiment of the present invention. The travel control apparatus  200  constitutes a part of the vehicle control apparatus  10  of  FIG. 1 . As illustrated in  FIG. 3 , the travel control apparatus  200  includes a controller  40 , a camera  11 , a radar  12 , and a LiDAR  13 . 
     The camera  11  is a monocular camera having an imaging element (image sensor) such as a CCD or a CMOS, and constitutes a part of the external sensor group  31  in FIG.  1 . The camera  11  may be a stereo camera. The camera  11  is attached to, for example, a predetermined position in the front of the subject vehicle  101 , continuously captures an image of a space in front of the subject vehicle  101 , and acquires an image (camera image) of an object. The object includes, for example, the other vehicles  102 ,  103  illustrated in  FIG. 2B . The camera  11  outputs image data including the camera image to the controller  40 . The radar  12  is mounted on the subject vehicle  101  and detects vehicles, obstacles, and the like around the subject vehicle  101  by irradiating with electromagnetic waves and detecting reflected waves. The radar  12  outputs a detection value (detection data) to the controller  40 . The LiDAR  13  is mounted on the subject vehicle  101 , and measures scattered light with respect to irradiation light in all directions of the subject vehicle  101  and detects a distance from the subject vehicle  101  to surrounding vehicles and obstacles. The LiDAR  13  outputs a detection value (detection data) to the controller  40 . 
     As illustrated in  FIG. 3 , the controller  40  includes a recognition unit  411 , a generation unit  412 , a calculation unit  413 , a determination unit  414 , and a correction unit  415  as functional configurations which the processing unit  41  is responsible for. The recognition unit  411  is configured by, for example, the exterior environment recognition unit  44  in  FIG. 1 . The generation unit  412 , the calculation unit  413 , the determination unit  414 , and the correction unit  415  are configured by, for example, the action plan generation unit  45  in  FIG. 1 . Here, each component will be described by taking, as an example, a case where the subject vehicle  101  is traveling in the traveling lane LN 2  of  FIG. 2B . 
     The recognition unit  411  recognizes the surrounding situation of the subject vehicle  101  based on the image data from the camera  11 , the detection data from the radar  12 , and the detection data from the LiDAR  13 . The generation unit  412  generates a target path of the subject vehicle from the current point of time to a predetermined time T ahead according to the surrounding situation recognized by the recognition unit  411 . When the recognition unit  411  recognizes the other vehicle  102  traveling on the lane LN 3  adjacent to one side of the traveling lane LN 2  of the subject vehicle  101  and the subject vehicle  101  is predicted to pass the side of the other vehicle  102 , the calculation unit  413  calculates a correction amount for correcting the target path generated by the generation unit  412  in a direction away from the other vehicle  102  in the vehicle width direction. The correction amount is calculated by the following Formula (I). CA is a correction amount of the target path calculated by the calculation unit  413 . LW is a width of the traveling lane of the subject vehicle  101 . VW is a vehicle width of the subject vehicle  101 . MG is a margin set in consideration of a recognition error or the like of a white line on a road. As the LW, a value recognized by the recognition unit  411  based on the image data from the camera  11  may be used, or a value obtained from the road information stored in the memory unit  42  may be used. When the width of the traveling lane of the subject vehicle  101  increases or decreases, the value of LW changes accordingly. In that case, CA is updated according to the change in the value of LW. 
         CA=LW/ 2− VW/ 2− MG   (I)
 
     When the other vehicle  103  traveling on the lane LN 1  adjacent to the other side of the traveling lane LN 2  of the subject vehicle  101  is recognized by the recognition unit  411 , the determination unit  414  determines whether to correct the target path of the subject vehicle  101  based on the traveling situation of the other vehicle  103 . 
       FIG. 4  is a diagram illustrating an example of a determination area for determining (deciding) whether to correct the target path. When the relative speed of the other vehicle  102  recognized by the recognition unit  411  is equal to or higher than a threshold and the position of the other vehicle  102  at a predetermined time point (a time point after the current time point) is included in the determination areas LA, RA, the determination unit  414  predicts that the subject vehicle  101  passes the side of the other vehicle  102  and determines to correct the target path. At this time, the determination unit  414  determines whether a time to collision (TTC) with the other vehicle  102  is less than a second threshold, in addition to whether a relative speed with respect to the other vehicle  102  is equal to or higher than a threshold (first threshold). When the TTC with the other vehicle  102  is less than the second threshold, the determination unit  414  determines that the correction of the target path is not in time, and determines not to correct the target path. That is, the determination unit  414  determines to correct the target path when it is predicted that the subject vehicle  101  passes through the side of the other vehicle  102  after the lapse of time equal to or longer than the minimum time required for completing the correction of the target path (correction to change the target path to a direction away from the other vehicle  102  in the vehicle width direction), and determines not to correct the target path when it is not predicted that the subject vehicle passes the side, that is, when it is determined that the correction of the target path is not in time. The determination areas LA, RA are areas whose length in the front-rear direction (the length of the subject vehicle  101  in the traveling direction, that is, the length in the left-right direction in  FIG. 4 ) is DL and whose length in the left-right direction (the length of the subject vehicle  101  in the vehicle width direction, that is, the length in the vertical direction in  FIG. 4 ) is DW. DW is set in advance based on a recognition error of the recognition unit  411  and a control error of the driving control unit  46 . DL is set based on a moving distance of the subject vehicle  101  from the current time point to a time point after a first predetermined time (≤predetermined time T). Hereinafter, the determination areas LA, RA will be described as two-dimensional areas for simplification of description, but the determination areas LA, RA may be three-dimensional areas having a height. When the position of the other vehicle  102  at the predetermined time point is included in an area (hereinafter, referred to as a correction prohibition area) within a distance IL from the subject vehicle  101  in the determination areas LA, RA, it is determined that the target path is not corrected. IL is set based on a moving distance of the subject vehicle  101  from the current time point to a time point after a second predetermined time (&lt;first predetermined time). This suppresses uncomfortable feeling and discomfort to the occupant caused by sudden steering. Hereinafter, an area other than the correction prohibition area in the determination areas LA, RA is referred to as a correction target area. 
     When the determination unit  414  determines to correct the target path, the correction unit  415  corrects the target path based on the correction amount calculated by the calculation unit  413 . Here, correction of the target path by the correction unit  415  will be described. First, correction of the target path when the other vehicle is recognized only in the lane LN 3  adjacent to one side of the traveling lane LN 2  of the subject vehicle  101  will be described.  FIGS. 5A to 5D  are diagrams for explaining correction of the target path. 
       FIG. 5A  illustrates the subject vehicle  101  traveling on the lane LN 2  and the other vehicle  102  traveling on the lane LN 3 . It is assumed that the traveling speed of the subject vehicle  101  is 50 kph and the traveling speed of the other vehicle  102  is 30 kph. That is, the relative speed of the subject vehicle  101  with respect to the other vehicle  102  is 20 kph (=50 kph −30 kph). A solid arrow line OR in the drawing represents a target path from the current time (hereinafter, time point t 0 ) to a predetermined time T ahead of the subject vehicle  101 . The other vehicle  102 P drawn by a broken line in the drawing schematically represents the other vehicle  102  at a predetermined time point. The predetermined time point is a time point that is a second predetermined time ahead from the current time point. A dashed-dotted line BD in the drawing represents a boundary between the correction prohibition area and the correction target area of the determination area RA. In the example illustrated in  FIG. 5A , since a part of the other vehicle  102 P is included in the determination area RA, when the relative speed of the subject vehicle  101  with respect to the other vehicle  102  is equal to or higher than the threshold, the target path OR is corrected to the target path indicated by the broken arrow line MV. When the TTC is considered together with the relative speed, the target path OR is corrected to the target path indicated by the broken arrow line MV when the relative speed is equal to or higher than the first threshold and the TTC is less than the second threshold. A broken line CN in the drawing represents a correction continuation path. The correction continuation path is a target path generated by the generation unit  412  when the target path is corrected by the correction unit  415 , and is a target path for causing the subject vehicle  101  to continuously travel at the position (position in the vehicle width direction) of the end point of the corrected target path MV. In  FIGS. 5A to 5D , the determination area LA is not illustrated. 
       FIG. 5B  illustrates a positional relationship between the subject vehicle  101  and the other vehicle  102  at a time point (hereinafter, time point t 1 ) after the time point t 0 . As illustrated in  FIG. 5B , when the subject vehicle  101  reaches the start point of the corrected target path MV, the subject vehicle  101  starts lateral movement (movement in the upward direction in the drawing) to separate from the other vehicle  102  along the target path MV. Hereinafter, the target path MV is also referred to as a lateral movement path. When the boundary BD is located between the start point and the end point of the lateral movement path MV, the generation unit  412  does not generate the target path. 
       FIG. 5C  illustrates a positional relationship between the subject vehicle  101  and the other vehicle  102  at a time point (hereinafter, time point t 2 ) after the time point t 1 . As illustrated in  FIG. 5C , when the position of the other vehicle  102  P (the other vehicle  102  at the time point second predetermined time ahead from the time point t 2 ) deviates from the determination area RA, the generation unit  412  generates a target path (hereinafter, referred to as a return path) for returning the subject vehicle  101  to the original position (position in the vehicle width direction). A broken arrow line RT in the drawing indicates a return path of the subject vehicle  101 . When the other vehicle  102  moves rightward (downward in the drawing) and thus the other vehicle  102  deviates from the determination area RA, the generation unit  412  generates a return path in the same manner. 
       FIG. 5D  illustrates a positional relationship between the subject vehicle  101  and the other vehicle  102  at a time point (hereinafter, time point t 3 ) after the time point t 2 . As illustrated in  FIG. 5D , when the subject vehicle  101  reaches the start point of the return path RT, the subject vehicle  101  starts lateral movement (movement in the downward direction in the drawing) along the return path RT and returns to the original position (position in the vehicle width direction). As described above, the target path of the subject vehicle  101  is corrected. As a result, the subject vehicle  110  can pass the side of the other vehicle  102  while avoiding approach to the other vehicle  102  in the vehicle width direction without causing a sudden change in travel control such as sudden steering. 
     Next, correction of the target path when the other vehicles (other vehicles  102 ,  103 ) are recognized in both the lane LN 3  adjacent to one side of the traveling lane LN 2  of the subject vehicle  101  and the lane LN 1  adjacent to the other side of the traveling lane LN 2  will be described. Here, a case where the other vehicle  102  is recognized in the lane LN 3  adjacent to one side (right side) of the traveling lane LN 2  of the subject vehicle  101 , the relative speed of the subject vehicle  101  with respect to the other vehicle  102  is equal to or higher than the threshold, and the position of the other vehicle  102  at a predetermined time point (time point after the current time point) is included in the determination area RA is taken as an example. In this case, when the other vehicle is not recognized in the lane LN 1  adjacent to the other side (left side) of the traveling lane LN 2  of the subject vehicle  101 , the target path of the subject vehicle  101  is corrected in a direction away from the other vehicle  102  in the vehicle width direction. However, when the other vehicle  103  is recognized in the lane LN 1  as illustrated in  FIG. 2B , if the target path of the subject vehicle  101  is corrected in a direction away from the other vehicle  102  in the vehicle width direction, the subject vehicle  101  and the other vehicle  103  may approach each other. Therefore, in order to avoid such approach, the determination unit  414  determines whether to correct the target path in a direction away from the other vehicle  102  in the vehicle width direction based on the traveling situation of the other vehicle  103 . Specifically, based on the traveling position, traveling speed, traveling acceleration, and the like of the other vehicle  103  recognized by the recognition unit  411 , the determination unit  414  predicts the distance (hereinafter, referred to as an approach distance) at which the subject vehicle  101  and the other vehicle  103  come closest to each other when the subject vehicle  101  travels along the corrected target path (correction of changing the target path in a direction away from the other vehicle  102  in the vehicle width direction). At this time, the determination unit  414  predicts the approach distance in the vehicle width direction and the approach distance in the traveling direction. The determination unit  414  determines to correct the target path when the predicted approach distance between the subject vehicle  101  and the other vehicle  103  in the vehicle width direction is equal to or greater than a first predetermined value, or when the predicted approach distance between the subject vehicle  101  and the other vehicle  103  in the traveling direction is equal to or greater than a second predetermined value. On the other hand, the determination unit  414  determines not to correct the target path when the predicted approach distance between the subject vehicle  101  and the other vehicle  103  in the vehicle width direction is less than the first predetermined value, and when the approach distance between the subject vehicle  101  and the other vehicle  103  in the traveling direction is less than the second predetermined value. The predetermined values (the first predetermined value and the second predetermined value) are set in advance based on a result of sensory evaluation or the like. Different values may be set for the first predetermined value and the second predetermined value. 
       FIG. 6  is a flowchart showing an example of processing executed by the CPU of the controller  40  in  FIG. 3  according to a prestored program. The processing illustrated in the flowchart is started, for example when the controller  40  is powered on, and is repeated at a predetermined cycle. 
     First, in step S 11 , the surrounding situation of the subject vehicle  101  is recognized. Specifically, it is determined whether or not the other vehicle (hereinafter, may be referred to as a first other vehicle) traveling in a lane adjacent to one side of the traveling lane of the subject vehicle  101  is recognized in front of the subject vehicle  101 . If the determination is negative in step S 11 , the processing ends. On the other hand, if the determination is affirmative in step S 11 , it is determined in step S 12  whether or not the subject vehicle  101  passes the side of the first other vehicle. More specifically, it is determined whether or not the relative speed of the subject vehicle  101  with respect to the first other vehicle is equal to or higher than a predetermined speed. If the determination is negative in step S 12 , the processing proceeds to step S 16 . If the determination is affirmative in step S 12 , in step S 13 , a correction amount for correcting the target path of the subject vehicle  101  in a direction away from the first other vehicle in the vehicle width direction is calculated. In step S 14 , it is determined whether or not the other vehicle (hereinafter, may be referred to as a second other vehicle) traveling in the other adjacent lane of the traveling lane of the subject vehicle  101  is recognized. If the determination is negative in step S 14 , the processing proceeds to step S 17 . If the determination is affirmative in step S 14 , it is determined in step S 15  whether or not the subject vehicle  101  approaches the second other vehicle when the target path of the subject vehicle  101  is corrected based on the correction amount calculated in step S 13 . That is, when the subject vehicle  101  travels along the corrected target path, it is determined whether or not a distance (approach distance) at which the subject vehicle  101  and the second other vehicle come closest to each other is less than a predetermined value. If the determination is affirmative in step S 15 , it is determined in step S 16  that the target path of the subject vehicle  101  is not corrected. On the other hand, if the determination is negative in step S 15 , it is determined in step S 17  that the target path of the subject vehicle  101  is corrected. 
     As described above, whether the target path of the subject vehicle  101  is corrected is determined. When it is determined to correct the target path of the subject vehicle  101 , correction of the target path as illustrated in  FIGS. 5A to 5D  is performed. However, as illustrated in  FIG. 7A , on a road RD on which a median strip MS is provided between the traveling lane LN 3  and the opposite lane LN 4 , when the subject vehicle  101  is traveling on the lane LN 3 , the first other vehicle (other vehicle  102 ) is traveling in the traveling lane LN 2 , and the second other vehicle (other vehicle  103 ) is an opposite vehicle traveling on the lane (opposite lane) LN 4  opposite to the lane LN 3 , the processing proceeds to step S 17  and it is determined to correct the target path without depending on the determination result of step S 15 , that is, without depending on the degree of approach between the subject vehicle  101  and the other vehicle  103 . As a result, it is possible to prevent unnecessary suppression of the correction of the target path. As illustrated in  FIG. 7B , when the second other vehicle (other vehicle  103 ) is stopped (parked or stopped) on a road shoulder or the like, the target path is not corrected. That is, the processing ends regardless of the determination results of steps S 14 , S 15 , and travel control for avoiding the other vehicle  103  that is stopped is performed. Description of the travel control performed at this time will be omitted. 
     According to the embodiment of the present invention, the following advantageous effects can be obtained: 
     (1) The travel control apparatus  200  includes: a recognition unit  411  that recognizes a surrounding situation of the subject vehicle  101 ; a generation unit  412  that generates a target path of the subject vehicle  101  according to the surrounding situation recognized by the recognition unit  411 ; a calculation unit  413  that calculates a correction amount for correcting the target path generated by the generation unit  412  in a direction away from a first other vehicle (the other vehicle  102  in  FIG. 2B ) in the vehicle width direction when the recognition unit  411  recognizes the first other vehicle that travels in a first adjacent lane (the lane LN 3  in  FIG. 2B ) which is adjacent to one side of the subject lane (the lane LN 2  in  FIG. 2B ) on which the subject vehicle  101  travels and in which the traveling direction is the same as that of the subject lane, and the subject vehicle  101  is predicted to pass a side of the first other vehicle; a determination unit  414  that determines whether or not to correct a target path based on a traveling situation of a second other vehicle (the other vehicle  411  in  FIG. 2B ) when the recognition unit  411  recognizes the second other vehicle (the other vehicle  103  in  FIG. 2B ) traveling in a second adjacent lane (the lane LN 1  in  FIG. 2B ) adjacent to the other side of the subject lane; and a correction unit  415  that corrects the target path based on the correction amount calculated by the calculation unit  413  when the determination unit  414  determines to correct the target path. As a result, the driving path can be corrected in an appropriate manner according to the surrounding situation of the vehicle. 
     (2) The determination unit  414  predicts a distance (first approach distance) in the vehicle width direction and a distance (second approach distance) in the traveling direction at which the subject vehicle comes closest to the second other vehicle when the subject vehicle  101  travels along the target path corrected by the correction unit  415  based on the traveling situation of the second other vehicle, and determines not to correct the target path when the predicted first approach distance or second approach distance is less than a predetermined value. As a result, when there is the other vehicle in a lane adjacent to the other side of the traveling lane of the subject vehicle, it is determined whether or not to correct the target path in consideration of the degree of approach to the other vehicle. Accordingly, the driving path can be corrected in a more appropriate manner according to the surrounding situation of the vehicle. 
     (3) When the second adjacent lane in which the second other vehicle is traveling is the opposite lane (lane LN 4  in  FIG. 7A ) of the subject lane in which the subject vehicle  101  is traveling and a separation zone (median strip MS in  FIG. 7A ) is provided between the subject lane and the opposite lane, the determination unit  414  determines not to correct the target path of the subject vehicle  101  even if the predicted first approach distance or second approach distance is less than a predetermined value. As a result, it is possible to prevent unnecessary suppression of the correction of the target path of the subject vehicle. Accordingly, the driving path can be corrected in a more appropriate manner according to the surrounding situation of the vehicle. 
     (4) The determination unit  414  sets, as a correction target area of the target path, a section between a first point at which the subject vehicle  101  reaches first predetermined time ahead and a second point at which the subject vehicle  101  reaches second predetermined time ahead shorter than the first predetermined time, and determines to correct the target path when the position of the first other vehicle after the second predetermined time is predicted to be included in the correction target area and the relative speed of the subject vehicle with respect to the first other vehicle is equal to or higher than a predetermined speed (first threshold). The determination unit  414  sets the section between the current position of the subject vehicle  101  and the second point as the correction prohibition area of the target path, and determines not to correct the target path when the position of the first other vehicle after the second predetermined time is predicted to be included in the correction prohibition area. This suppresses uncomfortable feeling and discomfort to the occupant caused by a sudden change in travel control such as sudden steering. Even when the position of the first other vehicle after the second predetermined time is predicted to be included in the correction target area and the relative speed of the subject vehicle  101  with respect to the first other vehicle is equal to or higher than the first threshold, the determination unit  414  determines not to correct the target path when the time to collision of the subject vehicle  101  with the first other vehicle is less than the second threshold value. As a result, it is possible to prevent the correction from being performed when the correction of the target path is not completed (cannot be made in time) before passing the side of the first other vehicle. 
     The above embodiment can be modified in various manners. Hereinafter, a modification will be described. In the above embodiment, when the position of the first other vehicle after the second predetermined time is predicted to be included in the correction target area and the relative speed of the subject vehicle with respect to the first other vehicle is equal to or higher than the first threshold, the determination unit  414  determines to correct the target path. However, the configuration of the determination unit is not limited thereto. For example, the determination unit may predict at predetermined time intervals whether the position of the first other vehicle after the second predetermined time is included in the correction target area, and may determine to correct the target path when the position of the first other vehicle after the second predetermined time is predicted to be included in the correction target area continuously a predetermined number of times. 
     In the above embodiment, the target path of the subject vehicle  101  is corrected based on the correction amount CA calculated by the above Formula (I). However, when the correction amount CA calculated in step S 13  is 0, the processing may proceed to step S 16  and it may be determined not to correct the target path of the subject vehicle  101 . 
     In the above embodiment, the case where the relative speed of the subject vehicle  101  with respect to the other vehicle  102  does not change has been described as an example, but the target path may be corrected in accordance with the change in the speed of the other vehicle  102 . For example, when the speed of the other vehicle  102  increases after the subject vehicle  101  laterally moves along the lateral movement path MV in  FIG. 5B , the relative speed of the subject vehicle with respect to the other vehicle  102  becomes 0, and a state in which the distance between the two vehicles is constant continues, the correction continuation path may be repeatedly generated so that the subject vehicle  101  travels at the position after the lateral movement until the state is eliminated. 
     In the above embodiment, when the median strip MS is provided between the subject lane LN 3  and the opposite lane LN 4  as illustrated in  FIG. 7A , the target path is corrected in a direction away from the other vehicle  103  (on the opposite lane LN 4  side) regardless of the result of the determination in step S 15 , that is, regardless of the degree of approach between the subject vehicle  101  and the other vehicle  102  traveling on the opposite lane LN 4 . 
     On the other hand, as illustrated in  FIG. 8 , when a separation zone is not provided between the subject lane LN 3  and the opposite lane LN 4 , if the target path of the subject vehicle  101  is corrected in a direction away from the other vehicle  102 , when the subject vehicle  101  approaches the other vehicle  103  in the opposite lane LN 4 , uncomfortable feeling and discomfort may be given to the occupant. Therefore, in order to cope with such a problem, when the other vehicle  103  traveling in the opposite lane LN 4  is recognized in front of the subject vehicle  101  in step S 14 , the determination unit may determine whether or not to correct the target path based on the distance between the subject vehicle and the other vehicle  103 . 
     Specifically, when the other vehicle  103  traveling in the opposite lane LN 4  is recognized by the recognition unit  411  on a road where no separation zone is provided between the subject lane LN 3  and the opposite lane LN 4 , the determination unit determines whether or not the distance between the subject vehicle  101  and the other vehicle  103  in the vehicle width direction at that time is equal to or greater than a third predetermined value. When the distance between the subject vehicle  101  and the other vehicle  103  in the vehicle width direction is equal to or greater than the third predetermined value, it is determined to correct the target path. The determination unit determines whether or not the distance in the traveling direction between the subject vehicle  101  and the other vehicle  103  at that time is equal to or greater than a fourth predetermined value. When the distance between the subject vehicle  101  and the other vehicle  103  in the traveling direction is equal to or greater than the fourth predetermined value, it is determined to correct the target path. The third predetermined value and the fourth predetermined value may be set in advance, or may be set based on the traveling position, traveling speed, traveling acceleration, and the like of the other vehicle  103  recognized by the recognition unit  411 . 
     In the above embodiment, when it is determined that the subject vehicle  101  will approach the second other vehicle traveling in the other adjacent lane if the target path is corrected in the vehicle width direction in a direction away from the first other vehicle when the subject vehicle passes the side of the first other vehicle traveling in the adjacent lane (YES in S 15 ), it is determined that the target path is not corrected (S 16 ). On the other hand, even when the first other vehicle passes the side of the subject vehicle  101 , the target path of the subject vehicle  101  is corrected in a direction away from the first other vehicle in the vehicle width direction, and the subject vehicle  101  may approach the second other vehicle traveling in the other adjacent lane. In order to cope with such a problem, the travel control apparatus  200  may be configured as follows. 
       FIG. 9  is a diagram illustrating an example of a determination area according to the present modification. When the relative speed of the other vehicle  102  recognized by the recognition unit  411  is equal to or higher than a threshold and the position of the other vehicle  102  at a predetermined time point (a time point after the current time point) is included in the determination areas RLA, RRA, the determination unit  414  predicts that the other vehicle  102  passes the side of the subject vehicle  101  and determines to correct the target path. In the determination areas RLA, RRA, the length in the front-rear direction is RDL, and the length in the left-right direction is RDW. Since RDW, RDL are set similarly to DW, DL, the description thereof will be omitted. As similar to LA, RA, the determination areas RLA, RRA may be three-dimensional areas having a height instead of two-dimensional areas. Of the determination areas RLA, RRA, an area within a distance RIL from the rear end of the subject vehicle  101  is set as a correction prohibition area. The distance RIL may be the same length as the distance IL, or a value different from the distance IL may be set. 
       FIG. 10  is a diagram illustrating an example of a scene where the other vehicle passes the side of the subject vehicle.  FIG. 10  illustrates the subject vehicle  101  traveling on the lane LN 2  and the other vehicle  102  traveling on the lane LN 3 . It is assumed that the traveling speed of the subject vehicle  101  is 30 kph and the traveling speed of the other vehicle  102  is 50 kph. That is, the relative speed of the other vehicle  102  with respect to the subject vehicle  101  is 20 kph (=50 kph −30 kph). A solid arrow line OR in the drawing represents a target path from the current time to a predetermined time T ahead of the subject vehicle  101 . The other vehicle  102 P drawn by a broken line in the drawing schematically represents the other vehicle  102  at a predetermined time point. The predetermined time point is a time point that is a second predetermined time (&lt;first predetermined time) ahead from the current time point. As similar to  FIG. 5A , a boundary BD is set at the position of a distance RIL from the subject vehicle  110 . 
     In the example illustrated in  FIG. 10 , since a part of the other vehicle  102 P is included in the determination area RRA, when the relative speed of the other vehicle  102  with respect to the subject vehicle  101  is equal to or higher than the threshold, the target path OR is corrected to the target path indicated by the broken arrow line MV. When the TTC is considered together with the relative speed, the target path OR is corrected to the target path indicated by the broken arrow line MV when the relative speed is equal to or higher than the first threshold and the TTC is less than the second threshold. A broken line CN in the drawing represents a correction continuation path. In  FIG. 10 , the determination area RLA is not illustrated. 
     As illustrated in  FIG. 10 , when the other vehicle  102  passes the side of the subject vehicle  101 , the target path of the subject vehicle  101  is corrected in a direction away from the other vehicle  102  in the vehicle width direction. At this time, if the other vehicle is present in the other adjacent lane LN 1 , the subject vehicle  101  may approach the other vehicle. Therefore, in the present modification, in step S 12 , it is determined whether or not the first other vehicle passes the side of the subject vehicle  101  in addition to whether or not the subject vehicle  101  passes the side of the first other vehicle. When it is determined that the subject vehicle  101  passes the side of the first other vehicle or when it is determined that the first other vehicle passes the side of the subject vehicle  101 , the processing proceeds to step S 13 . As a result, the driving path can be corrected in a more appropriate manner according to the surrounding situation of the vehicle. 
     In the above embodiment, the example in which the target path of the vehicle  101  is corrected with the lane adjacent to one side of the lane LN 2  on which the subject vehicle  101  travels as the lane LN 3 , the vehicle  102  traveling on the lane LN 3  as the first other vehicle, the lane adjacent to the other side of the lane LN 2  as the lane LN 1 , and the vehicle  103  traveling on the lane LN 1  as the second other vehicle has been described. However, the target path of the vehicle  101  may be corrected with the lane adjacent to one side of the lane LN 2  as the lane LN 1 , the vehicle  103  traveling on the lane LN 1  as the first other vehicle, the lane adjacent to the other side of the lane LN 2  as the lane LN 3 , and the vehicle  102  traveling on the lane LN 3  as the second other vehicle. 
     In the above embodiment, the recognition unit  411  recognizes the surrounding vehicles (the other vehicles  102 ,  103 ) of the subject vehicle  101  and the travel situation of the surrounding vehicle based on the image data and the like from the camera  11 , but the configuration of the recognition unit is not limited thereto. For example, the recognition unit may recognize a surrounding vehicle of the subject vehicle  101  and a traveling situation of the surrounding vehicle based on information received via the communication unit  37  by road-to-vehicle communication, vehicle-to-vehicle communication, or the like. 
     The present invention can be configured as a travel control method including: recognizing a surrounding situation of a subject vehicle; generating a target path of the subject vehicle according to the surrounding situation recognized in the recognizing; calculating a correction amount for correcting the target path generated in the generating in a direction away from a first other vehicle in the vehicle width direction, the first other vehicle traveling in a first adjacent lane in which a traveling direction is the same as a traveling direction of a subject lane on which the subject vehicle travels and which is adjacent to one side of the subject lane, when the first other vehicle is recognized in the recognizing and the subject vehicle is predicted to pass a side of the first other vehicle or the first other vehicle is predicted to pass a side of the subject vehicle; when a first other vehicle is recognized in the recognizing, the first other vehicle traveling in a first adjacent lane which is adjacent to one side of a subject lane on which the subject vehicle travels and whose traveling direction is the same as a traveling direction of the subject lane, and when the subject vehicle is predicted to pass through the side of the first other vehicle, or when the first other vehicle is predicted to pass through the side of the subject vehicle, calculating a correction amount for correcting the target path generated in the generating in a direction away from the first other vehicle in a vehicle width direction; determining whether to correct the target path based on a traveling situation of a second other vehicle traveling in a second adjacent lane which is adjacent to another side of the subject lane when the second other vehicle traveling in the second adjacent lane is recognized in the recognizing; and correcting the target path based on the correction amount calculated in the calculating when the target path is determined to be corrected in the determining. 
     when a first other vehicle is recognized in the recognizing, the first other vehicle traveling in a first adjacent lane which is adjacent to one side of a subject lane on which the subject vehicle travels and whose traveling direction is the same as a traveling direction of the subject lane, and when the subject vehicle is predicted to pass through the side of the first other vehicle, or when the first other vehicle is predicted to pass through the side of the subject vehicle, calculating a correction amount for correcting the target path generated in the generating in a direction away from the first other vehicle in a vehicle width direction. 
     determining whether to correct the target path based on a traveling situation of a second other vehicle traveling in a second adjacent lane which is adjacent to another side of the subject lane when the second other vehicle traveling in the second adjacent lane is recognized in the recognizing; 
     and correcting the target path based on the correction amount calculated in the calculating when the target path is determined to be corrected in the determining. 
     The above embodiment can be combined as desired with one or more of the above modifications. The modifications can also be combined with one another. 
     The present invention can correct the driving path of the vehicle in an appropriate manner according to the surrounding situation of the vehicle. 
     Above, while the present invention has been described with reference to the preferred embodiments thereof, it will be understood, by those skilled in the art, that various changes and modifications may be made thereto without departing from the scope of the appended claims.