Patent Publication Number: US-2022234577-A1

Title: Mobile object control device, mobile object control method,and storage medium

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Priority is claimed on Japanese Patent Application No. 2021-009983 filed on Jan. 26, 2021, the content of which is incorporated herein by reference. 
     BACKGROUND 
     Field of the Invention 
     The present invention relates to a mobile object control device, a mobile object control method, and a storage medium. 
     Description of Related Art 
     Automated traveling of a mobile object such as a vehicle (hereinafter referred to as “automated driving”) has been researched and put into practical use. In automated driving, a target trajectory is required to be generated automatically based on a situation of the traveling direction of the mobile object. 
     In this regard, Japanese Unexamined Patent Application, First Publication No. 2019-34627 discloses a vehicle control device including: a first setter that sets a first potential for a plurality of subareas into which a road area is divided on the basis of the road area; a second setter that sets a second potential for the subareas on the basis of a nearby object detected by a detector; an evaluator that derives an index value obtained by evaluating a potential of a subarea of interest out of the plurality of subareas on the basis of the first potential and the second potential set for the subarea of interest and prediction information generated for a nearby subarea selected from the vicinity of the subarea of interest; and a selector that selects one or more subareas in a traveling direction of a vehicle from the plurality of subareas on the basis of the index value derived by the evaluator. 
     SUMMARY 
     It is difficult to generate the target trajectory of automated driving as a continuous curve, and thus it is expected that the target trajectory is generated by a polygonal chain obtained by connecting points (trajectory points). The trajectory points have a moderate length of interval, and thus, in the related art, a risk area relating to an object having a small risk size may exist between trajectory points, with the result that the mobile object is determined to travel outside of the risk area irrespective of the fact that the target trajectory passes through the risk area and the risk of the target trajectory is not evaluated appropriately in some cases. 
     The invention is made in consideration of the above circumstances, and an object thereof is to provide a mobile object control device, a mobile object control method, and a storage medium, which are capable of evaluating a target trajectory appropriately and controlling a mobile object while suppressing increase in calculation load. 
     A mobile object control device, a mobile object control method, and a storage medium according to the invention employ the following configurations. 
     (1) A mobile object control device according to an aspect of the invention includes: a storage device that stores a program; and a hardware processor, the hardware processor executing the program stored in the storage device to: recognize an object which is located near a vehicle; generate a movement plan for the vehicle, which includes generation of a target trajectory in which the vehicle is to travel and which is obtained by connecting a plurality of trajectory points; and generate, when generating the movement plan, the target trajectory such that a line which is obtained by connecting trajectory points adjacent to each other with respect to a traveling direction of the vehicle does not pass through a risk area including the recognized object. 
     (2) In the aspect of (1), the hardware processor sets the risk area to have an ellipse shape. 
     (3) In the aspect of (2), the hardware processor performs deformation processing of converting the ellipse to a circle for the risk area set to have an ellipse shape, the deformation processing including shrinking the risk area and the line in a major axis direction of the ellipse or enlarging the risk area and the line in a minor axis direction of the ellipse, evaluates a degree of closeness of the target trajectory to the object based on a result of performing the deformation processing, and generates the target trajectory based on a result of the evaluation. 
     (4) In the aspect of (3), the hardware processor performs, before the deformation processing, rotation processing of rotating the risk area and the line around a center of the ellipse and matching the major axis and the minor axis of the ellipse with axes of the virtual plane. 
     (5) A mobile object control method to be executed by a computer mounted on a mobile body according to another aspect of the invention includes: recognizing an object which is located near a vehicle; generating a movement plan for the vehicle, which includes generation of a target trajectory in which the vehicle is to travel and which is obtained by connecting a plurality of trajectory points; and generating, when generating the movement plan, the target trajectory such that a line which is obtained by connecting trajectory points adjacent to each other with respect to a traveling direction of the vehicle does not pass through a risk area including the recognized object. 
     (6) A computer-readable non-transitory storage medium according to another aspect of the invention stores a program for causing a computer mounted on a mobile body to: recognize an object which is located near a vehicle; generate a movement plan for the vehicle, which includes generation of a target trajectory in which the vehicle is to travel and which is obtained by connecting a plurality of trajectory points; and generate, when generating the movement plan, the target trajectory such that a line which is obtained by connecting trajectory points adjacent to each other with respect to a traveling direction of the vehicle does not pass through a risk area including the recognized object. 
     According to the aspects of (1) to (6), it is possible to flexibly generate a target trajectory in various scenes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating a configuration of a vehicle system employing a vehicle control device according to an embodiment. 
         FIG. 2  is a diagram illustrating functional configurations of a first controller and a second controller. 
         FIG. 3  is a diagram illustrating candidate points, a first index, and a second index. 
         FIG. 4  is a diagram illustrating an example of a distribution of the first index and a distribution of the second index in a cross-section taken along line  4 - 4  in  FIG. 3 . 
         FIG. 5  is a diagram illustrating a reason why the first index is calculated for a candidate line. 
         FIG. 6  is a diagram illustrating a principle of calculating the first index for a candidate line. 
         FIG. 7  is a diagram illustrating details of rotation processing and deformation processing. 
         FIG. 8  is a diagram illustrating a condition for determining a flag value. 
         FIG. 9  is a diagram illustrating an example of a method of calculating the second index. 
         FIG. 10  is a (first) diagram illustrating a third index. 
         FIG. 11  is a (second) diagram illustrating the third index. 
         FIG. 12  is a diagram illustrating a target trajectory which is generated for a plurality of objects. 
         FIG. 13  is a flowchart illustrating an example of a process flow which is performed by the first controller. 
         FIG. 14  is a flowchart illustrating an example of a process flow which is performed by the first controller according to a second embodiment. 
         FIG. 15  is a diagram illustrating a process of a target trajectory generator according to a third embodiment. 
         FIG. 16  is a flowchart illustrating an example of a process flow which is performed by the first controller according to the third embodiment. 
         FIG. 17  is a diagram illustrating an example of a hardware configuration of an automated driving control device according to an embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In the following, a mobile object control device, a mobile object control method, and a storage medium according to an embodiment of the invention will be described with reference to the accompanying drawings. The following description relates to vehicle as a representative example of the mobile object. However, the mobile object is not limited to a vehicle, and can be applied to any type of mobile object that moves autonomously, such as micromobility and robots (including those with wheels and those that walk on multiple legs). 
     First Embodiment 
     [Entire Configuration] 
       FIG. 1  is a diagram illustrating a configuration of a vehicle system employing a vehicle control device according to an embodiment. A vehicle in which the vehicle system  1  is mounted is, for example, a vehicle with two wheels, three wheels, or four wheels and a drive source thereof is an internal combustion engine such as a diesel engine or a gasoline engine, an electric motor, or a combination thereof. The electric motor operates using electric power which is generated by a power generator connected to the internal combustion engine or electric power which is discharged from a secondary battery or a fuel cell. 
     The vehicle system  1  includes, for example, a camera  10 , a radar device  12 , a finder  14 , an object recognition device  16 , a communication device  20 , a human-machine interface (HMI)  30 , a vehicle sensor  40 , a navigation device  50 , a map positioning unit (MPU)  60 , a driving operator  80 , an automated driving control device  100 , a travel driving force output device  200 , a brake device  210 , and a steering device  220 . These devices or instruments are connected to each other via a multiplex communication line such as a controller area network (CAN) communication line, a serial communication line, a radio communication network, or the like. The elements illustrated in  FIG. 1  are only an example and some of the elements may be omitted or another element may be added thereto. 
     The camera  10  is, for example, a digital camera using a solid-state imaging device such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The camera  10  is attached to an arbitrary position on a vehicle (hereinafter referred to as a host vehicle M) in which the vehicle system  1  is mounted. When a scene in front of the vehicle M is imaged, the camera  10  is attached to an upper part of a front windshield, a rear surface of a rearview mirror, or the like. The camera  10  images surroundings of the host vehicle M, for example, periodically and repeatedly. The camera  10  may be a stereoscopic camera. 
     The radar device  12  radiates radio waves such as millimeter waves to the surroundings of the host vehicle M and detects at least a position (a distance and a direction) of an object by detecting radio waves (reflected waves) reflected by the object. The radar device  12  is attached to an arbitrary position on the host vehicle M. The radar device  12  may detect a position and a speed of an object using a frequency modulated continuous wave (FM-CW) method. 
     The finder  14  is a Light Detection And Ranging device (LIDAR). The finder  14  applies light to the surroundings of the host vehicle M and measures scattered light. The finder  14  detects a distance to an object on the basis of a time from emission of light to reception of light. The light which is applied is, for example, a pulse-like laser beam. The finder  14  is attached to an arbitrary position on the host vehicle M. 
     The object recognition device  16  performs a sensor fusion process on results of detection from some or all of the camera  10 , the radar device  12 , and the finder  14  and recognizes a position, a type, a speed, and the like of an object. The object recognition device  16  outputs the result of recognition to the automated driving control device  100 . The object recognition device  16  may output the results of detection from the camera  10 , the radar device  12 , and the finder  14  to the automated driving control device  100  without any change. The object recognition device  16  may be omitted from the vehicle system  1 . 
     The communication device  20  communicates with another vehicle near the host vehicle M, for example, using a cellular network, a Wi-Fi network, Bluetooth (registered trademark), or dedicated short range communication (DSRC), or various server devices via a radio base station. 
     The HMI  30  presents various types of information to an occupant of the host vehicle M and receives an input operation from the occupant. The HMI  30  includes various display devices, speakers, buzzers, touch panels, switches, and keys. 
     The vehicle sensor  40  includes a vehicle speed sensor that detects a speed of the host vehicle M, an acceleration sensor that detects acceleration, a yaw rate sensor that detects an angular velocity around a vertical axis, and a direction sensor that detects a direction of the host vehicle M. 
     The navigation device  50  includes, for example, a global navigation satellite system (GNSS) receiver  51 , a navigation HMI  52 , and a route determiner  53 . The navigation device  50  stores first map information  54  in a storage device such as a hard disk drive (HDD) or a flash memory. The GNSS receiver  51  identifies a position of the host vehicle M on the basis of signals received from GNSS satellites. The position of the host vehicle M may be identified or complemented by an inertial navigation system (INS) using the output of the vehicle sensor  40 . The navigation HMI  52  includes a display device, a speaker, a touch panel, and keys. All or a part of the navigation HMI  52  may be shared by the HMI  30 . For example, the route determiner  53  determines a route (hereinafter a route on a map) from the position of the host vehicle M identified by the GNSS receiver  51  (or an input arbitrary position) to a destination input by an occupant using the navigation HMI  52  with reference to the first map information  54 . The first map information  54  is, for example, information in which road shapes are expressed by links indicating roads and nodes connected by the links. The first map information  54  may include a curvature of a road or point of interest (POI) information. The route on a map is output to the MPU  60 . The navigation device  50  may perform guidance for a route using the navigation HMI  52  on the basis of the route on a map. The navigation device  50  may be realized, for example, by a function of a terminal device such as a smartphone or a tablet terminal which is carried by an occupant. The navigation device  50  may transmit a current position and a destination to a navigation server via the communication device  20  and may acquire a route which is equivalent to the route on a map from the navigation server. 
     The MPU  60  includes, for example, a recommended lane determiner  61  and stores second map information  62  in a storage device such as an HDD or a flash memory. The recommended lane determiner  61  divides the route on a map supplied from the navigation device  50  into a plurality of blocks (for example, every 100 [m] in a vehicle traveling direction) and determines a recommended lane for each block with reference to the second map information  62 . The recommended lane determiner  61  determines in which lane from the leftmost the vehicle will travel. When there is a branching point in the route on a map, the recommended lane determiner  61  determines a recommended lane such that the host vehicle M travels on a rational route for traveling to a branching destination. 
     The second map information  62  is map information with higher precision than the first map information  54 . The second map information  62  includes, for example, information of the center of a lane or information of boundaries of a lane. The second map information  62  may include road information, traffic regulation information, address information (addresses and postal codes), facility information, and phone number information. The second map information  62  may be updated from time to time by communicating with another device using the communication device  20 . 
     The driving operator  80  includes, for example, an accelerator pedal, a brake pedal, a shift lever, a steering wheel, a deformed steering, a joystick, and other operators. A sensor that detects an amount of operation or performing of an operation is attached to the driving operator  80 , and results of detection thereof are output to some or all of the automated driving control device  100 , the travel driving force output device  200 , the brake device  210 , and the steering device  220 . 
     The automated driving control device  100  is an example of a vehicle control device. The automated driving control device  100  includes, for example, a first controller  120  and a second controller  160 . The first controller  120  and the second controller  160  are realized, for example, by causing a hardware processor such as a central processing unit (CPU) to execute a program (software). Some or all of such elements may be realized in hardware (which includes circuitry) such as a large scale integration (LSI), an application specific integrated circuit (ASIC), or a field-programmable gate array (FPGA), or a graphics processing unit (GPU) or may be realized in cooperation of software and hardware. The program may be stored in a storage device such as an HDD or a flash memory of the automated driving control device  100  (a storage device including a non-transitory storage medium) in advance, or may be installed in the HDD or the flash memory of the automated driving control device  100  by storing the program in a detachable storage medium (the non-transitory storage medium) such as a DVD or a CD-ROM and attaching the storage medium to a drive device. 
       FIG. 2  is a diagram illustrating functional configurations of the first controller and the second controller. The first controller  120  includes, for example, a recognizer  130  and a movement plan generator  140 . The first controller  120  is realized, for example, by an artificial intelligence function and a function using a function based on artificial intelligence (AI) and a function based on a predetermined model in cooperation. For example, a function of “recognizing a crossing” may be embodied by performing recognition of a crossing based on deep learning or the like and recognition based on predetermined conditions (such as signals which can be pattern-matched and road signs) in cooperation, scoring both recognitions, and comprehensively evaluating both recognitions. Accordingly, reliability of automated driving is secured. 
     The recognizer  130  includes, for example, an object recognizer  132  and a traveling lane recognizer  134 . The object recognizer  132  recognizes states such as a position, a speed, and acceleration of an object near the host vehicle M on the basis of information which is input from the camera  10 , the radar device  12 , and the finder  14  via the object recognition device  16 . The object includes both of a stationary object and a moving object. For example, a position of an object is recognized as a position in an absolute coordinate system with an origin set to a representative point of the host vehicle M (such as the center of gravity or the center of a drive shaft) and is used for control. A position of an object may be expressed as a representative point such as the center of gravity or a corner of the object or may be expressed as a drawn area. A “state” of an object may include an acceleration or a jerk of the object or a “moving state” (for example, whether lane change is being performed or whether lane change is going to be performed) thereof. 
     The traveling lane recognizer  134  recognizes, for example, a relative position of a lane (a traveling lane) in which the host vehicle M is traveling with respect to the host vehicle M. For example, the traveling lane recognizer  134  recognizes the traveling lane by comparing a pattern of road markings near the host vehicle M which are recognized from an image captured by the camera  10  with a pattern of road markings (for example, arrangement of a solid line and a dotted line) which are acquired from the second map information  62 . The recognizer  130  may recognize the traveling lane by recognizing a traveling road boundary (a road boundary) including road markings, edges of a roadside, a curbstone, a median, and a guard rail as well as the road markings. In this recognition, the position of the host vehicle M acquired from the navigation device  50  and the result of processing from the INS may be considered. 
     The traveling lane recognizer  134  recognizes a position or a direction of the host vehicle M with respect to a traveling lane at the time of recognition of the traveling lane. The traveling lane recognizer  134  may recognize, for example, separation of a reference point of the host vehicle M from the lane center and an angle of the traveling direction of the host vehicle M with respect to a line formed by connecting the lane centers as the position and the direction of the host vehicle M relative to the traveling lane. Instead, the traveling lane recognizer  134  may recognize a position of the reference point of the host vehicle M relative to one side line of the traveling lane (a road marking or a road boundary) or the like as the position of the host vehicle M relative to the traveling lane. 
     The movement plan generator  140  includes, for example, a candidate point setter  141 , a first index deriver  142 , a second index deriver  143 , a third index deriver  144 , and a target trajectory generator  145 . Some or all of the candidate point setter  141 , the first index deriver  142 , the second index deriver  143 , and the third index deriver  144  may be included in the recognizer  130 . 
     The movement plan generator  140  generates a target trajectory in which the host vehicle M will travel automatedly (without requiring a driver&#39;s operation) in the future such that the host vehicle M travels in a recommended lane which is determined by the recommended lane determiner  61  in principle and copes with surrounding circumstances of the host vehicle M. The target trajectory generator  145  generates the target trajectory on the basis of a first index which is derived by the first index deriver  142 , a second index which is derived by the second index deriver  143 , and a third index which is derived by the third index deriver  144 . Details thereof will be described later. 
     For example, a target trajectory is expressed by sequentially arranging (connecting) points (trajectory points) at which a representative point (for example, the center of the front, the center of gravity, or the center between the rear wheels) of the host vehicle M will arrive at intervals of a predetermined distance (for example, about several [m]) in the road length direction. A target speed and target acceleration at intervals of a predetermined sampling time (for example, about below the decimal point [sec]) are added to the target trajectory. Trajectory points may be positions at which the host vehicle M is to arrive at predetermined sampling times every sampling time. In this case, information of the target speed or the target acceleration is expressed by intervals between the trajectory points. 
     The second controller  160  controls the travel driving force output device  200 , the brake device  210 , and the steering device  220  such that the host vehicle M passes along the target trajectory generated by the movement plan generator  140  as scheduled. 
     The second controller  160  includes, for example, an acquirer  162 , a speed controller  164 , and a steering controller  166 . The acquirer  162  acquires information of a target trajectory (trajectory points) which is generated by the movement plan generator  140  and stores the acquired information in a memory (not illustrated). The speed controller  164  controls the travel driving force output device  200  or the brake device  210  on the basis of a speed element pertained to the target trajectory stored in the memory. The steering controller  166  controls the steering device  220  on the basis of a curved state of the target trajectory stored in the memory. The processes of the speed controller  164  and the steering controller  166  are embodied, for example, by feed-forward control and feedback control in combination. For example, the steering controller  166  performs feed-forward control based on a curvature of a road in front of the host vehicle M and feedback control based on separation from the target trajectory in combination. 
     The travel driving force output device  200  outputs a travel driving force (a torque) for allowing the host vehicle to travel to the driving wheels. The travel driving force output device  200  includes, for example, a combination of an internal combustion engine, an electric motor, and a transmission and an electronic control unit (ECU) that controls them. The ECU controls the above-mentioned configuration on the basis of information input from the second controller  160  or information input from the driving operator  80 . 
     The brake device  210  includes, for example, a brake caliper, a cylinder that transmits a hydraulic pressure to the brake caliper, an electric motor that generates a hydraulic pressure in the cylinder, and a brake ECU. The brake ECU controls the electric motor on the basis of the information input from the second controller  160  or the information input from the driving operator  80  such that a brake torque based on a braking operation is output to vehicle wheels. The brake device  210  may include a mechanism for transmitting a hydraulic pressure generated by an operation of a brake pedal included in the driving operator  80  to the cylinder via a master cylinder as a backup. The brake device  210  may be an electronically controlled hydraulic brake device that controls an actuator on the basis of the information input from the second controller  160  such that the hydraulic pressure of the master cylinder is transmitted to the cylinder. 
     The steering device  220  includes, for example, a steering ECU and an electric motor. The electric motor changes a direction of turning wheels, for example, by applying a force to a rack-and-pinion mechanism. The steering ECU drives the electric motor on the basis of the information input from the second controller  160  or the information input from the driving operator  80  to change the direction of the turning wheels. 
     [Generation of Target Trajectory] 
     The method of generating a target trajectory will be described below in more detail. 
     The first index deriver  142  derives a first index R (a risk) that has a more negative value as the vehicle becomes closer to an object recognized by the object recognizer  132  for each line (hereinafter referred to as “candidate line”) connecting a plurality of candidate points (points) in the traveling direction of the host vehicle M and correlates the derived first index with the corresponding candidate points of the plurality of candidate points. “Correlates” means, for example, being stored as correlated information in the memory. In this embodiment, a plus value is defined as being “negative,” a value close to zero is defined as being “positive,” and a score which will be described later is defined as having a more positive value (a more preferable value) as the value becomes closer to zero, and vice versa. Accordingly, the first index deriver  142  derives the first index R that has a smaller value as the vehicle becomes closer to an object recognized by the object recognizer  132  for each of a plurality of candidate lines in the traveling direction of the host vehicle M. The first index deriver  142  includes a rotation/deformation processor  142 A and an index calculator  142 B. The functions of those sub-functional unit are described later. 
     The second index deriver  143  derives a second index B (a benefit) that has a smaller (more positive) value as the vehicle becomes closer to a recommended trajectory which is set in a predetermined rule for each of a plurality of candidate points in the traveling direction of the host vehicle M and correlates the derived second index with the corresponding candidate of the plurality of candidate points. 
       FIG. 3  is a diagram illustrating candidate points, the first index, and the second index. In the drawing, reference sign rT denotes a recommended route. The second index deriver  143  sets the center line of the recommended lane (L 1  in  FIG. 3 ) which is determined by the recommended lane determiner  61  as the recommended route rT. The invention is not limited thereto, and the second index deriver  143  may set a line which is biased to one of the right and left sides in the recommended lane as the recommended route rT. In a curved road, the recommended route has a curved shape. When the movement plan generator  140  changes the lane of the host vehicle M, a route which is directed from a certain lane to another adjacent lane may be set as the recommended route rT. 
     In the drawing, reference sign cK denotes a candidate point. The candidate point setter  141  sets a plurality of candidate points cK on a road in the traveling direction of the host vehicle M such that each candidate point has a width in a road length direction (an X direction) and a road width direction (a Y direction). A line connecting candidate points cK, which are adjacent to each other in the X direction, is a candidate line cLK. In the following description, the road length direction is referred to as a longitudinal direction and the road width direction is referred to as a lateral direction. In principle, the candidate point setter  141  sets a plurality of candidate points cK(Path x (i), Path y (i)) at intervals of a predetermined distance from the representative point rM of the host vehicle M on the recommended route rT (where i=1, 2, . . . , N), changes a position in the lateral direction of each candidate point cK by a predetermined width, and comprehensively sets the candidate points cK. The factor i is, for example, a value which is set in a receding order from the representative point of the host vehicle M. A candidate line connecting the candidate point cK(Path x (i), Path y (i)) and the candidate point cK(Path x (i+1), Path y (i+1)) is defined as a candidate line cLK(i). A line connecting the candidate points cK in the longitudinal direction is a candidate (temporary trajectory) for a target trajectory and the candidate points cK constituting the determined temporary trajectory, namely, the target trajectory are trajectory points. The candidate points cK on the recommended route rT may be referred to as a base path. As will be described later, the method of setting the candidate points cK is not limited to the searching method in the lateral direction with respect to the base path, and may employ a method of performing searching on the basis of a previous target trajectory. 
     In the drawing, reference sign OB denotes an object which is recognized by the object recognizer  132 , and reference sign P(R) denotes a distribution of the first index R. In the drawing, a dark part represents having a large value. The first index deriver  142  assumes an ellipse with respect to a representative point rOB of the object OB, for example, and derives the first index R for each candidate line cLK(i) such that the first index increases as a point of the candidate line cLK(i), which is closest to the representative point rOB, becomes closer to the center of the ellipse and decreases as the point becomes further away from the representative point rOB (i=1 to n). In the following description, the coordinates of the representative point rOB are expressed as (Object x , Object y ). The distribution P(R) of the first index R is derived to have an elliptical shape having a major axis in a desired direction in view of a certain contour line of values. The ratio between a major axis and a minor axis of the ellipse is changed, for example, depending on the length of the object OB in the longitudinal direction or the type of the object OB. An outer edge line of the ellipse in which the first index R is zero is expressed as eOB. The desired direction is, for example, an expected direction of movement of the object OB (in the case of a vehicle or a bicycle, the direction of the vehicle&#39;s axle or the direction of the wheels), or is the direction of extension of the road or the direction of travel of the vehicle when the object OB is a stationary object. These “directions” are recognized by the object recognizer  132 , for example. The desired direction is not limited thereto, but the desired direction may be determined in any way. Depending on the type of object OB, the distribution P(R) of the first index R may be set so that the contour lines of the values have the shape of a circle or have other shapes. 
     In the drawing, reference sign P(B) denotes a distribution of the second index B. In the drawing, a dark part represents having a large value. The second index deriver  143  derives the second index B that has a more positive value as it becomes closer to the recommended route rT (or the base path) for each candidate point cK. 
       FIG. 4  is a diagram illustrating a distribution P(R) of the first index R and a distribution P(B) of the second index B in a cross-section taken along line  4 - 4  in  FIG. 3 . The distribution P(R) of the first index R represents a distribution which has a peak at the position in the lateral direction of the center rOB of the object OB, has a smaller value as it becomes further away from the peak, and is zero when it becomes sufficiently far away from the peak. The distribution P(B) of the second index B is a distribution which is zero at the position in the lateral direction of the recommended route rT, has a larger value as it becomes further away from the recommended route rT, and has a constant value in an area of a lane L 2  adjacent to a recommended lane L 1  (which may also have a larger value as it becomes further away from the recommended route rT in the area of the lane L 2  instead). The distribution P(B) of the second index B may be set such that it decreases in the vicinity of the center line of the lane L 2 . 
     The reason for calculating the first index R not for the candidate point cK but for the candidate line cLK will be described below in more detail.  FIG. 5  is a diagram illustrating a reason why the first index R is calculated for the candidate line cLK. In  FIG. 5 , the i-th candidate point cK(Path x (i), Path x (i)) and the (i+1)-th candidate point cK(Path x (i+1), Path x (i+1)) are both outside the outer edge eOB of the ellipse where the first index R is zero, and if the first index R is calculated for the candidate point cK, the illustrated candidate for the target trajectory is not penalized by the first index R. However, when the host vehicle M actually travels along this candidate target trajectory, as can be seen from the fact that the candidate line cLK(i) passes through the inside of the outer edge line eOB of the ellipse, the representative point of the host vehicle M may pass through the inside of the outer edge line eOB of the ellipse, resulting in an undesirable situation. When the interval between the candidate point cK and a trajectory point K is set sufficiently narrow, the frequency of occurrence of such issues can be reduced. However, the shorter the interval becomes, the greater the load on the computer processing becomes, and there is a concern that vehicle control may be delayed due to reception of delayed results. Therefore, development is carried out on the premise that the interval between the candidate point cK and the trajectory point K is set to a value with a certain width. In the automatic driving control system  100  (vehicle control system) according to the embodiment, the first index R is calculated for the candidate line cLK to solve such a problem. 
     When determining the first index R for a candidate line cLK, the rule is, for example, as follows.  FIG. 6  is a diagram illustrating a principle of calculating the first index R for the candidate line cLK. In principle, the first index deriver  142  draws contour lines of an ellipse shape from the center of the ellipse to the outer edge line eOB, and set a value corresponding to a point (nearest point) on the candidate line cLK, which intersects the innermost contour line, as the first index R for the candidate line cLK. The first index R corresponding to the nearest point is calculated to be closer to 1 as the point becomes closer to the center of the ellipse, and is calculated to be zero on and outside the outer edge eOB of the ellipse. This value can be obtained directly by some calculation method, but the geometric calculation becomes complicated. 
     Therefore, in the embodiment, the rotation/deformation processor  142 A and the index calculator  142 B perform the processing described below to reduce the calculation load of the first index R.  FIG. 7  is a diagram illustrating details of rotation processing and deformation processing. When calculating the first index R for the object OB, the rotation/deformation processor  142 A first rotates the ellipse and the candidate line cLK around the center rOB of the ellipse (i.e., the center of the object) so that the major axis and the minor axis of the ellipse, which is the risk area set for the object OB, are aligned with the two axes on a virtual plane for the calculation (in  FIG. 7 , the axes are assumed to be the same as the XY axes, which are the road coordinate axes, but are not limited thereto). Next, the rotation/deformation processor  142 A shrinks the ellipse and candidate line cLK in the major axis direction (or enlarging the ellipse and candidate line cLK in the minor axis direction) so that the length of the major axis of the ellipse matches the length of the minor axis. As a result, the outer edge line eOB of the ellipse becomes the shape of a circle. The rotation/deformation processor  142 A further performs the processing of enlarging or shrinking the outer edge line eOB and the candidate line cLK so that the radius of the outer edge line eOB, which has become a circle, becomes 1. The outer edge line eOB* after this rotation and enlargement/shrinking is denoted as eOB*. 
     After the processing, the index calculator  142 B determines a flag value Flag(i) for each candidate line cLK.  FIG. 8  is a diagram illustrating a condition for determining the flag value Flag(i). In  FIG. 8 , the end points of some candidate line cLK(i) in focus are denoted as A and B, and the center rOB of the object is denoted as the center point C for description. The index calculator  142 B sets the flag value Flag (i) to 1 when at least one of the following conditions 1 and 2 is satisfied, and the condition 3 is satisfied, or sets the flag value Flag (i) to 0 otherwise. 
     (Condition 1) 
     The angle φ(V AB /V AC ) between the vector V AB  from the endpoint A to the endpoint B and the vector V AC  from the endpoint A to the center point C, and the angle φ(V BA /V BC ) between the vector V BA  from the endpoint B to the endpoint A and the vector V BC  from the endpoint B to the center point C are both acute angles. 
     (Condition 2) 
     At least one of the distance D AC  between the end point A and the center point C and the distance D BC  between the end point B and the center point C is equal to or less than 1 
     (Condition 3) 
     The distance D CL  between the straight line containing the candidate line cLK(i) and the center point C is equal to or less than 1. The index calculator  142 B calculates the distance D CL  based on Expression (1). In the following, the distance D CL  with respect to the candidate line cLK(i) is denoted as the distance D CL (i). 
     The index calculator  142 B calculates the distance based on Equation (1), and calculates the first index R Path  for a certain temporary trajectory based on Expression (2). Expressions (1) and (2) are focused on a single object OB. When a plurality of OBs exist in the vicinity of the temporary trajectory, the index calculator  142 B calculates the first indices R Path_ob1 , R Path_ob2 , . . . focusing on each OB based on Expressions (1) and (2), and then calculates the first index R Path  by adding those values. It is conceivable that the distance D CL (i) is equal to or less than 1, and the entire candidate line cLK(i) is outside of eOB*. In that state, the conditions 1 and 2 are not satisfied, and thus the term {Flag(i)×D CL (i)} in R Path  becomes zero. 
         D   CL ( i )={Path x ( i )×Path y ( i+ 1)−Path x ( i+ 1)×Path y ( i )}/√[{Path x ( i+ 1)−Path x ( i )} 2 +{Path y ( i+ 1)−Path y ( i )} 2 ]  (1)
 
         R   Path   =Σi= 1 N {Flag( i )× D   CL ( i )}  (2)
 
       FIG. 9  is a diagram illustrating an example of the method of calculating the second index B. The second index deriver  143  calculates a square of a distance D rTi  between a candidate point cK and a candidate point on the base path corresponding to the position in the longitudinal direction as the second index B for each candidate point cK. The distance D rTi  is calculated using Expression (3). In the expressions, Base x (i) denotes the X coordinate of the i-th candidate point on the base path and Base y (i) denotes the Y coordinate of the i-th candidate point on the base path. When a candidate point cK is detected in the lateral direction with respect to the candidate point cK on the base path, Path x (i)-Base x (i) is zero. When a certain temporary trajectory is set and candidate points constituting the temporary trajectory are cK(i) (i=1, 2, . . . , N), the second index B Path  for the temporary trajectory is expressed by Expression (4). 
         D   rTi =√{(Path x ( i )−Base x ( i )) 2 +(Path y ( i )−Base y ( i )) 2 }  (3)
 
         B   Path =Σ i=1   N   {D   rTi }  (4)
 
     For example, two calculation sequences below can be considered as a calculation sequence including deriving the first index R and the second index B, and any calculation sequence thereof may be employed. A process flow illustrated in  FIG. 13  which will be described later is based on the idea of Sequence 2. 
     (Sequence 1) 
     Candidates are comprehensively set→the first index R is derived for a line connecting all the candidate points, and the second index B is derived for all the candidate points to be stored in a memory→a temporary trajectory is set→the first index R and the second index B of each candidate point on the temporary trajectory are read from the memory. 
     (Sequence 2) 
     Candidate points are set→a temporary trajectory is set→the first index R is derived for a line connecting all the candidate points, and the second index B is derived for the candidate points on the temporary trajectory. 
     The third index deriver  144  derives a third index by evaluating a shape of a temporary trajectory connecting a plurality of candidate points cK in the longitudinal direction. The target trajectory generator  145  generates a target trajectory on the basis of the first index R, the second index B, and the third index, whereby unnecessary sudden turning of the host vehicle M is curbed. 
     The third index deriver derives the third index by evaluating smoothness of a temporary trajectory on the basis of some or all of three factors of (1) to (3) which will be described below. In the following description, it is assumed that the third index deriver derives the third index on the basis of all of the three factors, and the three factors are referred to as third indices C 1 , C 2 , and C 3 . A factor t means that a control cycle corresponds to a t-th process while the constituents of the first controller  120  perform processes periodically repeatedly. Now, description will be made with a focus on a process of the t-th control cycle. 
       FIG. 10  is a (first) diagram illustrating a third index. 
     (1) The third index deriver calculates a distance ΔY1(i−1, i, t) in the lateral direction between a candidate point cK(i, t) and a candidate point cK(i−1, t) in the t-th control cycle (the current control cycle) for i=1 to N, and derives a square sum thereof as the third index C 1  (Expression (5)). For example, cK(0, t) denotes a representative point rM of the host vehicle M. By decreasing the third index C 1 , it is possible to set a shape of a target trajectory to a simple shape with a small change in the lateral direction and to curb sudden turning of the host vehicle M. 
         C 1=Σ i=1   N   {ΔY 1( i− 1,1, t ) 2 }  (5)
 
       FIG. 11  is a (second) diagram illustrating a third index. 
     (2) The third index deriver compares a target trajectory TJ(t−c) generated in the (t−C)-th control cycle (a previous control cycle) with candidate points cK(i, t) in the t-th control cycle (the current control cycle), calculates a distance ΔY2(i, t−C, t) in the lateral direction between a position cK #(i, t−C) on the target trajectory TJ(t−C) of which the position in the longitudinal direction matches the candidate point cK(i, t) and the candidate point cK(i, C) for i=1 to N, and derives a square sum thereof as the third index C 2  (Expression (6)). Since the target trajectory TJ(t−C) is strictly a set of trajectory points K, a polygonal chain connecting the trajectory points K which are continuous in the longitudinal direction is referred to as a target trajectory TJ(t−C). C is a natural number equal to or greater than 1. In the example illustrated in  FIG. 11 , C=1 is set. By decreasing the third index C 2 , it is possible to curb temporal change of a target trajectory which is repeatedly generated with the elapse of time and to curb sudden turning of the host vehicle M. 
         C 2=Σ i=1   N   {ΔY 2( i− 1, i−C,t ) 2 }  (6)
 
       FIG. 10  will be referred to for description below. 
     (3) The third index deriver derives a square of an angle θ(V →   MK(p,t−E) , V →   MK(p,t) ) which is formed by a vector V →   MK(p,t)  directed from the representative point rM of the host vehicle M to the p-th candidate point cK(p,t) in the t-th control cycle (the current control cycle) and a vector V →   MK(p,t−E)  directed from the representative point rM of the host vehicle M to the p-th candidate point cK(p,t−E) in the t−E-th control cycle (the current control cycle) as the third index C 3  (Expression (7)). The vectors may be expressed as being “straight lines” but are referred to as vectors. E is a natural number equal to or greater than 1. By decreasing the third index C 3 , it is possible to curb temporal change of a future point which affects movement of the host vehicle M in the target trajectory and to curb sudden turning of the host vehicle M. 
         C 3=θ 2   (7)
 
     The target trajectory generator  145  generates a target trajectory on the basis of the first index R, the second index B, and the third index. For example, the target trajectory generator  145  derives a score by inputting the first index R, the second index B, and the third index to a function, and sets a plurality of candidate points cK in a combination with the smallest value as a plurality of trajectory points K constituting the target trajectory. The score is derived, for example, by calculating a weighted sum of the first index R, the second index B, and the third indices C 1 , C 2 , and C 3  as expressed by Expression (8). Instead, the score may be derived using an arbitrary method such as multiplying together some or all of the first index R, the second index B, and the third indices as long as the gist of the invention is not changed. “The gist of the invention is not changed” means that a trend to decrease the score as the first index R decreases, to decrease the score as the second index B decreases, and to decrease the score as the third index decreases is maintained. Each of w1, w2, w3, w4, and w5 is an arbitrary positive value. 
       Score( t )= w 1× R   Path   +w 2× B   Path   +w 3× C 1+ w 4× C 2+ w 5× C 3  (8)
 
     Through the above process, it is possible to decrease a probability of sudden turning of the host vehicle M in comparison with a case in which a target trajectory is generated on the basis of only the first index R and the second index B. Since the process of generating a target trajectory based on only the first index R and the second index B and the process of evaluating the shape of a trajectory are not separated from each other, it is possible to flexibly generate a target trajectory in various scenes. 
     An object is not limited to a stationary object and may be an object which moves at a lower speed than that of the host vehicle M such as a bicycle or a pedestrian. In this case, the first index deriver  142  may derive the first index R in consideration of the elapse of time. 
       FIG. 12  is a diagram illustrating a target trajectory which is generated for a plurality of objects. In the drawing, OB 2  denotes a second object (a bicycle), P(R) OB1  denotes a distribution of a first index R corresponding to the first object OB 1  and P(R) OB2  denotes a distribution of a second index R corresponding to the second object OB 2 . P(R) OB1  has an elliptical shape centered on a representative point rOB 1  of the object OB 1 , and P(R) OB2  has a circular shape centered on a position of each destination with movement of a representative point rOB 2  of the object OB 2 . The sizes of the distributions are different from each other, and the first index deriver  142  adjusts the sizes of the distributions, for example, on the basis of the sizes of the objects OB. The first index deriver  142  estimates that a moving route of the representative point rOB 2  traces, for example, the outer edge of the distribution of the first index R for the first object OB 1 , and estimates the future position of the representative point rOB 2  on the basis of the current speed of the object OB 2 . Distributions P(R) OB2,1 , P(R) OB2,2 , P(R) OB2,3 , P(R) OB2,4 , . . . , P(R) OB2,j  of the first index R are set for the future positions of the representative points rOB 2 . The factor j in P(R) OB2,j  is the concept of time having the same period as j of a control cycle time. That is, the factor j denotes after how many control cycles the object OB 2  has a position. 
     The first index deriver  142  may simply overlap the distributions P(R) OB2,1 , P(R) OB2,2 , P(R) OB2,3 , P(R) OB2,4 , . . . , P(R) OB2 , of the first index R which are generated as described without considering the time and handle the overlapped distributions as the distribution of the first index R of the second object OB 2 , or may not consider the distribution of the first index R with a small factor j corresponding to the time required, for example, for arrival at a candidate point cK(k) which has a large k, that is, which is far from the host vehicle M, out of the candidate points cK(k) in consideration of movement of the second object OB 2 . For example, depending on the speed of the host vehicle M, the first index R may be allocated to candidate points cK(k) in k≥Th1 in consideration of only P(R) OB2,j  in j≥Th2. 
       FIG. 13  is a flowchart illustrating an example of a process flow which is performed by the first controller  120 . The process flow of the flowchart is repeatedly performed for each control cycle time which is described above. 
     First, the object recognizer  132  recognizes an object in the traveling direction of the host vehicle M (Step S 100 ) and the traveling lane recognizer  134  recognizes the relative position of the traveling lane with respect to the host vehicle M (Step S 102 ). 
     Then, the candidate point setter  141  sets candidate points (Step S 104 ) and sets a plurality of temporary trajectory in which the candidate points are connected in the longitudinal direction (Step S 106 ). 
     Then, the first index deriver  142 , the second index deriver  143 , and the third index deriver  144  derive a first index R Path , a second index B Path , and the third indices C 1  to C 3 , respectively, for each temporary trajectory (Step S 108 ). 
     Then, the target trajectory generator  145  calculates the score for each temporary trajectory (Step S 110 ) and sets a temporary trajectory with the smallest score as a target trajectory (Step S 112 ). 
     Instead of exhaustively selecting provisional trajectories and calculating scores as described above, the automated driving control device  100  may generate a target trajectory by simultaneous perturbation stochastic approximation (SPSA). SPSA is a type of stochastic gradient method using random variables. In this case, the automated driving control device  100  can generate a target trajectory more quickly by applying the score calculation method described above to SPSA compared to the case of exhaustively selecting provisional trajectories. 
     In the above description, it is assumed that the first index, the second index, and the third index are calculated and the target trajectory is generated by integrating those indices. However, the processing corresponding to the second and third indices may be omitted or modified as appropriate, for example, as long as the first index is obtained by the above-mentioned method. 
     The automated driving control device  100  according to the first embodiment described above includes: an object recognizer  132  that recognizes an object in the vicinity of the vehicle M; and a movement plan generator  140  that generates a movement plan for the vehicle M, which includes generating a target trajectory in which the vehicle M is to travel and which is obtained by connecting a plurality of trajectory points. The movement plan generator  140  generates a target trajectory so that the line connecting trajectory points adjacent to each other with respect to the traveling direction of the vehicle M does not enter the risk area including the recognized object. Therefore, it is possible to evaluate the target trajectory appropriately and control the vehicle while suppressing the increase in calculation load. 
     Second Embodiment 
     A second embodiment will be described below. In the first embodiment, setting of a temporary trajectory is not particularly limited, but in the second embodiment, when an upper limit is provided in the distance ΔY1 (see  FIG. 10 ) in the lateral direction between candidate points cK adjacent in the longitudinal direction and there is any distance ΔY1 greater than the upper limit, the corresponding temporary trajectory is excluded from candidates for a target trajectory. Here, it is assumed that the distance does not have a directional element. That is, a process of excluding a temporary trajectory including a part in which the distance ΔY1 is greater than a threshold value Th Y  from calculation targets of the score in advance is performed as a pre-process. Accordingly, it is possible to further decrease a probability of sudden turning of the host vehicle M. 
       FIG. 14  is a flowchart illustrating an example of a process flow which is performed by the first controller  120  according to the second embodiment. The process flow in the flowchart is repeatedly performed for each control cycle time which is described above. The processes of Steps S 100  to S 106  and the processes of Steps S 108  to S 112  are the same as described above with reference to  FIG. 13  and description thereof will be omitted. 
     Subsequent to the process of Step S 106 , the candidate point setter  141  excludes a temporary trajectory including a part in which the distance ΔY1 is greater than the threshold value Th Y  from temporary trajectories connecting candidate points in the longitudinal direction (Step S 107 ). 
     First, instead of comprehensively setting temporary trajectories and excluding a temporary trajectory in which every distance ΔY1 is greater than the threshold value Th Y , a search range (a search angle) may be limited such that the distance ΔY1 is not greater than the threshold value Th Y  when the temporary trajectories are sequentially searched from an end in the longitudinal direction. 
     According to the second embodiment described above, it is possible to achieve the same advantages as in the first embodiment and to further decrease a probability of sudden turning of the host vehicle M. Since the process of calculating the score is performed after the temporary trajectories are narrowed, it is possible to decrease a process load. 
     Third Embodiment 
     A third embodiment will be described below. In the third embodiment, the target trajectory generator  145  ascertains whether a target trajectory selected on the basis of a score includes a part in which the distance ΔY1 is greater than the threshold value Th Y , and corrects the target trajectory such that the distance ΔY1 becomes equal to or less than the threshold value Th Y  when there is a part in which the distance ΔY1 is greater than the threshold value Th Y . 
       FIG. 15  is a diagram illustrating a process flow which is performed by the target trajectory generator  145  according to the third embodiment. In the drawing, a q-th trajectory point K(q, t) and a (q−1)-th trajectory point K(q−1, t) have a relationship in which the distance ΔY1 in the lateral direction therebetween is greater than the threshold value Th Y . Since the target trajectory has been generated already, the points are referred to as “trajectory points K” instead of “candidate points cK.” In the distance ΔY1 in the third embodiment, candidate points are replaced with trajectory points. 
     In this case, for example, the target trajectory generator  145  selects an object which is closest to the trajectory point K and corrects the position of the q-th trajectory point K(q, t) or the (q−1)-th trajectory point K(q−1, t) in the lateral direction such that the trajectory point K becomes further away from the representative point of the object. In the example illustrated in  FIG. 15 , since a representative point rOB of an object OB is located on the left side when seen from a trajectory point K(q), the target trajectory generator  145  moves the position of the (q−1)-th trajectory point K(q−1, t) in a direction in which it becomes further away from the representative point rOB of the object OB, that is, to the right. The target trajectory generator  145  sets, for example, an amount of movement thereof to a minimum amount of movement in which the distance ΔY1 is not greater than the threshold value Th Y . As a result of this process, when the distance in the lateral direction between the (q−1)-th trajectory point K(q−1, t) and the (q−2)-th trajectory point K(q−2, t) is greater than the threshold value Th Y , the target trajectory generator  145  moves the (q−2)-th trajectory point K(q−2, t) to the right. The target trajectory generator  145  according to the third embodiment repeatedly performs this process in a spreading manner until all the distances ΔY1 are equal to or less than the threshold value Th Y . 
     In this process, it is necessary to determine a trajectory point K at which the distance ΔY1 is first ascertained. If this trajectory point is not determined, there is a likelihood that the process will spread from both sides and will not converge. For example, the target trajectory generator  145  according to the third embodiment sets a trajectory point K with the largest amount of displacement in the lateral direction from the base path (a u-th trajectory point K(u, t) in  FIG. 15 ) as a search start point and ascertains whether the distance ΔY1 is greater than the threshold value ThY to both a near side (a side getting closer to the host vehicle M) and a distant side (a side getting further away from the host vehicle M) from the search start point. 
       FIG. 16  is a flowchart illustrating an example of a process flow which is performed by the first controller  120  according to the third embodiment. The process flow in the flowchart is repeatedly performed for each control cycle which is described above. The processes of Steps S 100  to S 112  are the same as described above with reference to  FIG. 13  and description thereof will be omitted. 
     When a target trajectory is generated, the target trajectory generator  145  sets a trajectory point which is the most distant in the lateral direction from the representative point rM of the host vehicle M as a search start point (Step S 118 ). Then, the target trajectory generator  145  sequentially determines whether there is a part in which the distance ΔY1 is greater than the threshold value Th Y  to both the near side and the distant side from the search start point (Step S 120 ). When it is determined that there is a part in which the distance ΔY1 is greater than the threshold value Th Y , the target trajectory generator  145  moves some trajectory points of the part to the side opposite to the closest object to correct the target trajectory (Step S 122 ). Then, the target trajectory generator  145  sets the corrected trajectory point as the search start point (Step S 124 ) and performs the process of Step S 120  again (Step S 120 ). Here, search to the sides opposite to the near side and the distant side is not performed. When there is no part in which the distance ΔY1 is greater than the threshold value Th Y , processing of one control cycle of the flowchart ends. 
     According to the third embodiment described above, it is possible to achieve the same advantages as in the first embodiment and to further decrease a probability of sudden turning of the host vehicle M. 
     [Hardware Configuration] 
       FIG. 17  is a diagram illustrating an example of a hardware configuration of the automated driving control device  100  according to the embodiment. As illustrated in the drawing, the automated driving control device  100  has a configuration in which a communication controller  100 - 1 , a CPU  100 - 2 , a random access memory (RAM)  100 - 3  that is used as a work memory, a read only memory (ROM)  100 - 4  that stores a booting program or the like, a storage device  100 - 5  such as a flash memory or a hard disk drive (HDD), a drive device  100 - 6 , and the like are connected to each other via an internal bus or a dedicated communication line. The communication controller  100 - 1  communicates with elements other than the automated driving control device  100 . A program  100 - 5   a  which is executed by the CPU  100 - 2  is stored in the storage device  100 - 5 . This program is loaded into the RAM  100 - 3  by a direct memory access (DMA) controller (not illustrated) or the like and is executed by the CPU  100 - 2 . Accordingly, one or both of the first controller  120  and the second controller  160  are embodied. 
     While the invention has been described above with reference to an embodiment, the invention is not limited to the embodiment and can be subjected to various modifications and substitutions without departing from the gist of the invention.