Patent Publication Number: US-11027735-B2

Title: Vehicle control apparatus, vehicle control method, and vehicle control program

Description:
TECHNICAL FIELD 
     The present invention relates to a vehicle control apparatus, a vehicle control method, and a vehicle control program. 
     Priority is claimed on Japanese Patent Application No. 2015-156206, filed on Aug. 6, 2015, the contents of which are incorporated herein by reference. 
     BACKGROUND 
     Recently, techniques are desired in which a lane change when traveling is automatically performed depending on a relative relationship between a self-vehicle (hereinafter, also referred to as a first vehicle or simply a vehicle) and a peripheral vehicle. In relation to this, a travel assist apparatus is known which includes an assist start part that starts an assist of a lane change according to an input of an input device, a detection part that detects a relative distance and a relative speed between a self-vehicle (hereinafter, also referred to as a first vehicle or simply a vehicle) and another vehicle (hereinafter, also referred to as a second vehicle or other vehicles), a calculation part that calculates a collision risk degree when the vehicle performs a lane change with respect to another vehicle according to the relative distance and the relative speed detected by the detection part, a first determination part that determines whether or not it is possible to perform a lane change according to the relative distance, the relative speed, and the collision risk degree, a determination part that determines a target space by which a lane change is performed according to the relative distance and the relative speed when the first determination part determines that it is not possible to perform a lane change, a second determination part that determines whether or not there is a space by which a lane change can be performed in the target space, a setting part that sets a target speed toward a lane change waiting position when the second determination part determines that there is not the space and sets a target speed toward a lane change available position when it is determined that there is the space, and a control part that controls the speed of the vehicle so as to be the target speed (for example, refer to Patent Document 1). 
     Further, in relation to the above technique, a lane change assist apparatus is known which includes a vehicle state detection means, a peripheral vehicle detection means, a lane detection means, a merging end setting means, a peripheral vehicle behavior prediction means, a vehicle operation amount setting means that generates one or more operation amount time series until a vehicle arrives at a merging end, an operation amount determination means that determines whether it is possible to perform an appropriate lane change when performing each operation amount time series generated by the vehicle operation amount setting means and determines by which one of gaps between peripheral vehicles that travel on a lane of a lane change destination it is possible to perform a lane change if it is possible to perform an appropriate lane change, and an assist information presentation means that transmits a correspondence relationship between the gap and the operation of the vehicle obtained by the operation amount determination means to a driver (for example, refer to Patent Document 2). 
     Related Art Documents 
     [Patent Document 1] Japanese Unexamined Patent Application, First Publication No. 2009-078735 
     [Patent Document 2] Japanese Unexamined Patent Application, First 
     Publication No. 2005-038325 
     SUMMARY OF INVENTION 
     Problems to be Solved by the Invention 
     However, in the related art, when a peripheral vehicle is not detected by a detection part such as a radar and a camera, or when the detection accuracy of a peripheral vehicle is low, there may be a case in which it is not possible to perform flexible automated driving. 
     In view of the foregoing, an object of an aspect of the present invention is to provide a vehicle control apparatus, a vehicle control method, and a vehicle control program capable of performing further flexible automated driving. 
     Means for Solving the Problem 
     (1) An aspect of the present invention is a vehicle control apparatus which includes: a first detection part that is configured to detect a peripheral vehicle which is traveling around a vehicle; a control plan generation part that is configured to generate a control plan of the vehicle according to the peripheral vehicle which is detected by the first detection part; and a travel control part that is configured to control acceleration, deceleration, or steering of the vehicle according to the control plan which is generated by the control plan generation part, wherein the control plan generation part is configured to generate the control plan of the vehicle according to a peripheral vehicle that satisfies a predetermined condition among one or more peripheral vehicles that are detected by the first detection part, and wherein when it is not possible to detect the peripheral vehicle that satisfies the predetermined condition, the control plan generation part is configured to set a virtual vehicle which virtually simulates the peripheral vehicle that satisfies the predetermined condition and generate the control plan of the vehicle. 
     (2) In the above aspect (1), when it is not possible to detect the peripheral vehicle that satisfies the predetermined condition, the control plan generation part may set the virtual vehicle in the vicinity of an outer edge of a detection region of the first detection part. 
     (3) In the above aspect (2), the control plan generation part may set the virtual vehicle as a stationary body in the vicinity of the outer edge of the detection region of the first detection part. 
     (4) In the above aspect (2), the control plan generation part may set the virtual vehicle as a movable body in the vicinity of the outer edge of the detection region of the first detection part. 
     (5) In the above aspect (1), the vehicle control apparatus may include a second detection part that detects a disappearance region of a lane or an appearance region of a lane according to one or both of a detection result by the first detection part and map information relating to a lane on which the vehicle can travel, wherein when it is not possible to detect the peripheral vehicle that satisfies the predetermined condition, and when a disappearance region of a lane or an appearance region of a lane is detected in a detection region of the first detection part by the second detection part, the control plan generation part may set the virtual vehicle around the disappearance region of the lane or around the appearance region of the lane. 
     (6) In the above aspect (5), the control plan generation part may set the virtual vehicle as a stationary body around the disappearance region of the lane or around the appearance region of the lane. 
     (7) In the above aspect (1), the vehicle control apparatus may include a third detection part that detects an occlusion which indicates a state in which there is a possibility that the peripheral vehicle is present in a detection region of the first detection part and it is not possible to detect the peripheral vehicle by a screening object, wherein when the occlusion is detected by the third detection part, the control plan generation part may set the virtual vehicle around a region in which the occlusion occurs. 
     (8) In any one of the above aspects (1) to (7), the vehicle control apparatus may further include a target position candidate setting part that sets, when the vehicle performs a lane change, a lane change target position candidate which represents a position candidate of a lane change destination of the vehicle in an adjacent lane that is adjacent to a lane on which the vehicle travels, wherein the peripheral vehicle that satisfies the predetermined condition may be at least one of a frontward traveling vehicle that is traveling at a frontward position of the vehicle in the lane, a lane-change target-position candidate frontward-traveling vehicle that is traveling at a frontward position of the lane change target position candidate, and a lane-change target-position candidate rearward-traveling vehicle that is traveling at a rearward position of the lane change target position candidate. 
     (9) Another aspect of the present invention is a vehicle control method, by way of an in-vehicle computer, including: detecting a peripheral vehicle which is traveling around a vehicle; generating a control plan of the vehicle according to the detected peripheral vehicle; controlling acceleration, deceleration, or steering of the vehicle according to the generated control plan; generating the control plan of the vehicle according to a peripheral vehicle that satisfies a predetermined condition among one or more peripheral vehicles that are detected by the first detection part; and setting a virtual vehicle which virtually simulates the peripheral vehicle that satisfies the predetermined condition and generating the control plan of the vehicle when it is not possible to detect the peripheral vehicle that satisfies the predetermined condition. 
     (10) Still another aspect of the present invention is a vehicle control program that causes an in-vehicle computer to: detect a peripheral vehicle which is traveling around a vehicle; generate a control plan of the vehicle according to the detected peripheral vehicle; control acceleration, deceleration, or steering of the vehicle according to the generated control plan; generate the control plan of the vehicle according to a peripheral vehicle that satisfies a predetermined condition among one or more peripheral vehicles that are detected by the first detection part; and set a virtual vehicle which virtually simulates the peripheral vehicle that satisfies the predetermined condition and generate the control plan of the vehicle when it is not possible to detect the peripheral vehicle that satisfies the predetermined condition. 
     Advantage of the Invention 
     According to the aspects (1), (2), (9), and (10) described above, since the control plan of the vehicle is generated according to a peripheral vehicle that satisfies a predetermined condition among one or more peripheral vehicles that are detected by the first detection part, and when it is not possible to detect the peripheral vehicle that satisfies the predetermined condition, a virtual vehicle which virtually simulates the peripheral vehicle that satisfies the predetermined condition is set to generate the control plan of the vehicle, it is possible to perform further flexible automated driving. 
     According to the aspects (3), (4), and (6) described above, the virtual vehicle is set as a stationary body or a movable body, and therefore, it is possible to perform automated driving more safely. 
     According to the aspect (5) described above, when a disappearance region of a lane or an appearance region of a lane is detected, the virtual vehicle is set around the disappearance region of the lane or around the appearance region of the lane, and therefore, it is possible to perform further flexible automated driving in response to the travel lane. 
     According to the aspect (7) described above, when the occlusion is detected, the virtual vehicle is set around a region in which the occlusion occurs, and therefore, it is possible to perform further flexible automated driving in accordance with an environment when traveling. 
     According to the aspect (8) described above, when any one or more of the frontward traveling vehicle, the lane-change target-position candidate frontward-traveling vehicle, and the lane-change target-position candidate rearward-traveling vehicle are not detected by the detection part, a vehicle that is not detected by the detection part is set as the virtual vehicle, and therefore, it is possible to reduce the cost of calculating the state estimation of the peripheral vehicle which is performed when performing automated driving. 
     According to the aspects (6), (7), and (8) described above, the virtual vehicle is set as a stationary body or a movable body, and therefore, it is possible to perform automated driving further safely. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view showing a configuration element included in a vehicle on which a vehicle control apparatus according to a first embodiment is provided. 
         FIG. 2  is a function configuration view of a vehicle focusing on the vehicle control apparatus according to the first embodiment. 
         FIG. 3  is a view showing a state in which a relative position of a vehicle with respect to a travel lane is recognized by a vehicle position recognition unit. 
         FIG. 4  is a view showing an example of an action plan that is generated with respect to a zone. 
         FIG. 5  is a view showing a state in which a target position candidate setting part in the first embodiment sets a lane change target position candidate. 
         FIG. 6  is a flowchart showing an example of a process flow of a lane change control part in the first embodiment. 
         FIG. 7  is a flowchart showing an example of a flow of a setting process of a virtual vehicle. 
         FIG. 8  is a view showing an example of a scene in which a frontward traveling vehicle is not recognized in a detection region. 
         FIG. 9  is a view showing an example of a state in which the virtual vehicle is set in the vicinity of an outer edge of the detection region. 
         FIG. 10  is a view showing another example of the state in which the virtual vehicle is set in the vicinity of the outer edge of the detection region. 
         FIG. 11  is a view showing an example of a scene in which a lane-change target-position candidate frontward-traveling vehicle is not recognized in the detection region. 
         FIG. 12  is a view showing an example of a scene in which a lane-change target-position candidate rearward-traveling vehicle is not recognized in the detection region. 
         FIG. 13  is a view showing an example of, in a case where a peripheral vehicle that becomes a determination target is recognized, a positional relationship between the vehicle and the peripheral vehicle. 
         FIG. 14  is a view showing patterns into which the position change of the peripheral vehicle is categorized with respect to Pattern (a) of the vehicle positional relationship. 
         FIG. 15  is a view showing patterns into which the position change of the peripheral vehicle is categorized with respect to Pattern (b) of the vehicle positional relationship. 
         FIG. 16  is a view showing an example of, in a case where part of a peripheral vehicle that becomes a determination target is not recognized, a positional relationship between the vehicle and the peripheral vehicle. 
         FIG. 17  is a view showing patterns into which the position change of the peripheral vehicle is categorized with respect to Pattern (c) of the vehicle positional relationship. 
         FIG. 18  is a view showing an example of a travel trajectory used for a lane change that is generated by a travel trajectory generation part. 
         FIG. 19  is a flowchart showing an example of a process flow of a lane change control part in a second embodiment. 
         FIG. 20  is a view showing an example of a scene in which a disappearance region of a lane is detected in a detection region. 
         FIG. 21  is a flowchart showing another example of the process flow of the lane change control part in the second embodiment. 
         FIG. 22  is a view showing an example of a scene in which an appearance region of a lane is detected in the detection region. 
         FIG. 23  is a function configuration view of a vehicle focusing on a vehicle control apparatus according to a third embodiment. 
         FIG. 24  is a flowchart showing an example of a process flow of an inter-vehicle distance control unit in the third embodiment. 
         FIG. 25  is a view showing an example of a scene in which an occlusion occurs in a detection region. 
         FIG. 26  is a view showing a state in which the vehicle is performing an inter-vehicle communication while traveling. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, a vehicle control apparatus, a vehicle control method, and a vehicle control program according to embodiments of the present invention are described with reference to the drawings. 
     First Embodiment 
     Vehicle Configuration 
       FIG. 1  is a view showing a configuration element included in a vehicle M (hereinafter, also referred to as a first vehicle M) on which a vehicle control apparatus  100  according to a first embodiment is provided. A vehicle on which the vehicle control apparatus  100  is provided is, for example, an automobile having two wheels, three wheels, four wheels, or the like and includes an automobile using an internal combustion engine such as a diesel engine and a gasoline engine as a power source, an electric automobile using an electric motor as a power source, a hybrid automobile including both an internal combustion engine and an electric motor, and the like. The electric automobile described above is driven, for example, by using electric power discharged by a battery such as a secondary battery, a hydrogen fuel cell, a metallic fuel cell, and an alcohol fuel cell. 
     As shown in  FIG. 1 , a sensor such as finders  20 - 1  to  20 - 7 , radars  30 - 1  to  30 - 6 , and a camera  40 , a navigation device  50 , and the vehicle control apparatus  100  are provided on the vehicle. The finders  20 - 1  to  20 - 7  are, for example, LIDARs (Light Detection and Ranging, or Laser Imaging Detection and Ranging) that measure scattered light with respect to irradiation light and that measure a distance to a target. For example, the finder  20 - 1  is attached to a front grille and the like, and the finders  20 - 2  and  20 - 3  are attached to a side surface of a vehicle body, a door mirror, the inside of a head lamp, the vicinity of a side lamp, and the like. The finder  20 - 4  is attached to a trunk lid and the like, and the finders  20 - 5  and  20 - 6  are attached to a side surface of the vehicle body, the inside of a tail lamp, and the like. The finders  20 - 1  to  20 - 6  have, for example, a detection region of about 150 degrees with respect to a horizontal direction. The finder  20 - 7  is attached to a roof and the like. The finder  20 - 7  has, for example, a detection region of 360 degrees with respect to the horizontal direction. 
     The radars  30 - 1  and  30 - 4  are, for example, long-distance millimeter-wave radars having a wider detection region in a depth direction than that of other radars. The radars  30 - 2 ,  30 - 3 ,  30 - 5 , and  30 - 6  are middle-distance millimeter-wave radars having a narrower detection region in the depth direction than that of the radars  30 - 1  and  30 - 4 . Hereinafter, when the finders  20 - 1  to  20 - 7  are not specifically distinguished, the finders  20 - 1  to  20 - 7  are described simply as “a finder  20 ”, and when the radars  30 - 1  to  30 - 6  are not specifically distinguished, the radars  30 - 1  to  30 - 6  are described simply as “a radar  30 ”. The radar  30  detects an object, for example, by a FM-CW (Frequency Modulated Continuous Wave) method. 
     The camera  40  is, for example, a digital camera that uses a solid-state imaging element such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). The camera  40  is attached to an upper part of a front window shield, a rear surface of a room mirror, and the like. For example, the camera  40  periodically and repeatedly captures an image of the frontward direction of the vehicle M. 
     The configuration shown in  FIG. 1  is merely an example. Part of the configuration may be omitted, or another configuration may be further added. 
       FIG. 2  is a function configuration view of the vehicle M focusing on the vehicle control apparatus  100  according to the first embodiment. The vehicle M includes the navigation device  50 , a vehicle sensor  60 , a communication unit  65 , a travel drive force output device  72 , a steering device  74 , a brake device  76 , an operation device  78 , an operation detection sensor  80 , a switch  82 , and the vehicle control apparatus  100  in addition to the finder  20 , the radar  30 , and the camera  40 . These devices and equipment are mutually connected by a multiplex communication line such as a CAN (Controller Area Network) communication line, a serial communication line, a wireless communication network, and the like. 
     The navigation device  50  has a GNSS (Global Navigation Satellite System) receiver, map information (navigation map), a touch-panel display device that functions as a user interface, a speaker, a microphone, and the like. The navigation device  50  identifies the position of the vehicle M by the GNSS receiver and derives a route to a destination that is assigned by a user from the position. The route that is derived by the navigation device  50  is stored in a storage part  130  as route information  134 . The position of the vehicle M may be identified or supplemented by an INS (Inertial Navigation System) that utilizes an output of the vehicle sensor  60 . The navigation device  50  performs a guide with respect to the route to the destination by speech or a navigation display when the vehicle control apparatus  100  is performing a manual driving mode. The configuration that identifies the position of the vehicle M may be provided independently from the navigation device  50 . The navigation device  50  may be realized by, for example, a function of a terminal apparatus such as a smartphone or a tablet terminal held by a user. In this case, transmission and reception of information are performed using a radio frequency or a communication between the terminal apparatus and the vehicle control apparatus  100 . The configuration that identifies the position of the vehicle M may be provided independently from the navigation device  50 . 
     The vehicle sensor  60  includes a vehicle speed sensor that detects a vehicle speed, an acceleration sensor that detects acceleration, a yaw rate sensor that detects an angular speed around a vertical axis, an azimuth sensor that detects the direction of the vehicle M, and the like. 
     The communication unit  65  performs, for example, an inter-vehicle communication with a peripheral vehicle and acquires information such as the position and the speed of the peripheral vehicle. The communication unit  65  outputs the information such as the position and the speed acquired from the peripheral vehicle to the vehicle control apparatus  100 . 
     The travel drive force output device  72  includes an engine and an engine ECU (Electronic Control Unit) that is configured to control the engine, for example, when the vehicle M is an automobile using an internal combustion engine as a power source. The travel drive force output device  72  includes a travel motor and a motor ECU that is configured to control the travel motor, for example, when the vehicle M is an electric automobile using an electric motor as a power source. The travel drive force output device  72  includes an engine, an engine ECU, a travel motor, and a motor ECU, for example, when the vehicle M is a hybrid automobile. When the travel drive force output device  72  includes only an engine, the engine ECU adjusts the throttle opening degree of the engine, a shift step, and the like and outputs a travel drive force (torque) by which the vehicle travels in accordance with information input from a travel control part  120  described below. When the travel drive force output device  72  includes only a travel motor, the motor ECU adjusts the duty ratio of a PWM signal that is given to the travel motor and outputs the travel drive force described above in accordance with information input from the travel control part  120 . When the travel drive force output device  72  includes an engine and a travel motor, both of the engine ECU and the motor ECU controls a travel drive force in a mutually coordinated manner in accordance with information input from the travel control part  120 . 
     The steering device  74  includes, for example, an electric motor, a steering torque sensor, a steering angle sensor, and the like. For example, the electric motor applies a force to a rack-and-pinion function and the like and changes the direction of a steering wheel. The steering torque sensor detects the torsion of a torsion bar, for example, when the steering wheel is operated, as a steering torque (steering force). The steering angle sensor detects, for example, a steering angle (or actual steering angle). The steering device  74  drives the electric motor and changes the direction of the steering wheel in accordance with information input from the travel control part  120 . 
     The brake device  76  includes a master cylinder in which a brake operation applied to a brake pedal is transmitted as an oil pressure, a reservoir tank that reserves a brake fluid, a brake actuator that adjusts a brake force output to each wheel, and the like. A brake control part  44  controls a brake actuator and the like such that a brake torque which corresponds to the pressure of a master cylinder is output to each wheel in accordance with information input from the travel control part  120 . The brake device  76  is not limited to an above-described electronically-controlled brake device which operates by the oil pressure and may be an electronically-controlled brake device which operates by an electric actuator. 
     The operation device  78  includes, for example, an accelerator pedal, a steering wheel, a brake pedal, a shift lever, and the like. An operation detection sensor  80  that detects the presence or absence of operation by a driver and the amount of operation is attached to the operation device  78 . The operation detection sensor  80  includes, for example, an accelerator opening degree sensor, a steering torque sensor, a brake sensor, a shift position sensor, and the like. The operation detection sensor  80  outputs an accelerator opening degree, a steering torque, a brake press amount, a shift position, and the like as a detection result to the travel control part  120 . Alternatively, the detection result of the operation detection sensor  80  may be directly output to the travel drive force output device  72 , the steering device  74 , or the brake device  76 . 
     The switch  82  is a switch that is operated by a driver and the like. The switch  82  may be, for example, a mechanical switch that is arranged on the steering wheel, a garnish (dashboard), and the like or may be a GUI (Graphical User Interface) switch that is provided on a touch panel of the navigation device  50 . The switch  82  accepts an operation of the driver or the like and generates a control mode designation signal that designates an operation mode by the travel control part  120  to any one of an automated driving mode and a manual driving mode to output the control mode designation signal to a control switch unit  122 . The automated driving mode is a driving mode in which the vehicle travels in a state where the driver does not perform an operation (alternatively, the operation amount is smaller than that of the manual driving mode, or the operation frequency is small) as described above. More specifically, the automated driving mode is a driving mode in which part of or all of the travel drive force output device  72 , the steering device  74 , and the brake device  76  are controlled according to an action plan. 
     Vehicle Control Apparatus 
     Hereinafter, the vehicle control apparatus  100  is described. The vehicle control apparatus  100  includes, for example, a vehicle position recognition unit  102 , an outside recognition unit  104 , an action plan generation unit  106 , a lane change control unit  110 , a travel control unit  120 , the control switch unit  122 , and a storage unit  130 . Part of or all of the vehicle position recognition unit  102 , the outside recognition unit  104 , the action plan generation unit  106 , the lane change control unit  110 , the travel control unit  120 , and the control switch unit  122  are software function units that functions by executing a program by a processor such as a CPU (Central Processing Unit). Part of or all of the units may be hardware function units such as a LSI (Large Scale Integration) and an ASIC (Application Specific Integrated Circuit). The storage unit  130  is realized by a ROM (Read Only Memory), a RAM (Random Access Memory), a HDD (Hard Disk Drive), a flash memory, and the like. The program executed by the processor may be stored in the storage unit  130  in advance or may be downloaded from an external device via an in-vehicle Internet system and the like. The program executed by the processor may be installed in the storage unit  130  by mounting a portable storage medium that stores the program on a drive device (not shown). 
     The vehicle position recognition unit  102  recognizes the lane (travel lane) on which the vehicle M is travelling and the relative position of the vehicle M with respect to the travel lane according to map information  132  that is stored in the storage unit  130  and information that is input from the finder  20 , the radar  30 , the camera  40 , the navigation device  50 , or the vehicle sensor  60 . The map information  132  is, for example, map information having higher accuracy than a navigation map included in the navigation device  50  and includes information of the center of a lane, information of the boundary of a lane, or the like. More specifically, the map information  132  includes road information, traffic regulation information, address information (address and zip code), facility information, phone number information, and the like. The road information includes information showing the class of a road such as a freeway, a toll road, a national road, or a prefectural road and information of the lane number of a road, the width of each lane, the gradient of a road, the position of a road (three-dimensional coordinate including the longitude, latitude, and height), the curvature of a curve of a lane, the position of merging and branching points of a lane, a sign provided on a road, and the like. The traffic regulation information includes information of the closure of a lane due to a work, a traffic accident, a traffic jam, and the like. 
       FIG. 3  is a view showing a state in which the relative position of the vehicle M with respect to a travel lane L 1  is recognized by the vehicle position recognition unit  102 . For example, the vehicle position recognition unit  102  recognizes, as the relative position of the vehicle M with respect to the travel lane L 1 , a gap OS of a reference point (for example, the center of gravity) of the vehicle M from a travel lane center CL and an angle θ formed by the travel direction of the vehicle M with respect to a line formed of the continued travel lane centers CL. Alternatively, the vehicle position recognition unit  102  may recognize, as the relative position of the vehicle M with respect to the travel lane, the position of the reference point of the vehicle M with respect to any of side end parts of the travel lane L 1  (the lane on which the vehicle M travels) and the like. 
     The outside recognition unit  104  recognizes a state of the position, speed, acceleration, and the like of a peripheral vehicle according to information that is input from the finder  20 , the radar  30 , the camera  40 , and the like. The peripheral vehicle in the present embodiment is a vehicle that is traveling in the vicinity of the vehicle M and is a vehicle that is traveling in the same direction as the vehicle M. The position of a peripheral vehicle may be represented by a representative point such as the center of gravity or a corner of another vehicle (hereinafter, also referred to as a second vehicle) or may be represented by a region described by the outline of another vehicle. The “state” of a peripheral vehicle may include the acceleration of the peripheral vehicle and whether or not the peripheral vehicle is changing a lane (or whether or not the peripheral vehicle will change a lane) according to the information of the devices described above. The outside recognition unit  104  recognizes whether or not the peripheral vehicle is changing a lane (or whether or not the peripheral vehicle will change a lane) according to the position history of the peripheral vehicle, the operation state of a direction indicator, and the like. The outside recognition unit  104  may recognize positions of a guardrail, a power pole, a parked vehicle, a pedestrian, and other objects in addition to a peripheral vehicle. Hereinafter, the combination of the finder  20 , the radar  30 , the camera  40 , and the outside recognition unit  104  is referred to as a “detection part DT” that detects a peripheral vehicle. The “detection part DT” may further recognize the state of the position, speed, and the like of a peripheral vehicle by a communication with the peripheral vehicle. The detection part DT in the first embodiment is an example of a “first detection part”. 
     The action plan generation unit  106  generates an action plan in a predetermined zone. The predetermined zone is, for example, a zone, which includes a toll road such as an expressway, of the route that is derived by the navigation device  50 . The predetermined zone is not limited thereto, and the action plan generation unit  106  may generate an action plan with respect to an arbitrary zone. 
     The action plan is constituted of, for example, a plurality events that are sequentially performed. Examples of the events include a deceleration event that decelerates the vehicle M, an acceleration event that accelerates the vehicle M, a lane keeping event that causes the vehicle M to travel so as not to be deviated from the travel lane, a lane change event that changes the travel lane, an overtaking event that causes the vehicle M to overtake a frontward traveling vehicle, a branching event that changes the lane to a desired lane at a branching point or causes the vehicle M to travel so as not to be deviated from the current travel lane, a merging event that causes the vehicle M to accelerate or decelerate at a lane merging point to change the travel lane, and the like. For example, when a junction (branching point) is present in a toll road (for example, an expressway or the like), it is necessary for the vehicle control apparatus  100  to change the lane or keep the lane such that the vehicle M proceeds to a target direction in an automated driving mode. Accordingly, when it is determined that a junction is present on the route with reference to the map information  132 , the action plan generation unit  106  sets a lane change event that changes a lane to a desired lane by which it is possible to proceed to the destination direction, at a position from the current position (coordinate) of the vehicle M to the position (coordinate) of the junction. The information that indicates the action plan which is generated by the action plan generation unit  106  is stored in the storage part  130  as action plan information  136 . 
       FIG. 4  is a view showing an example of an action plan that is generated with respect to a zone. As shown in the drawing, the action plan generation unit  106  categorizes situations that arise when traveling in accordance with the route to the destination and generates the action plan such that an event which is suitable for the individual situation is performed. The action plan generation unit  106  may change the action plan dynamically in response to the change in circumstances of the vehicle M. 
     The action plan generation unit  106  may change (update) the generated action plan, for example, according to the state of the outside environment that is recognized by the outside recognition unit  104 . In general, the state of the outside environment constantly changes while the vehicle is traveling. Specifically, when the vehicle M travels on a road that includes a plurality of lanes, the distance spacing with another vehicle is relatively changed. For example, when another frontward vehicle suddenly brakes to reduce the speed, or another vehicle that is traveling on an adjacent lane cuts into the space in front of the vehicle M, it is necessary for the vehicle M to travel while appropriately changing the speed or the lane in accordance with the behavior of another frontward vehicle or the behavior of another vehicle on the adjacent lane. Accordingly, the action plan generation unit  106  may change the event that is set for each control zone in response to the state change of the outside environment as described above. 
     Specifically, when the speed of another vehicle that is recognized by the outside recognition unit  104  while the vehicle is traveling exceeds a threshold value, or when the movement direction of another vehicle that is traveling on the adjacent lane which is adjacent to the travel lane is directed to the travel lane direction, the action plan generation unit  106  changes the event that is set in a drive zone in which the vehicle M is scheduled to travel. For example, in a case where the event is set such that a lane change event is performed after a lane keeping event, when it is determined by the recognition result of the outside recognition unit  104  that, in the lane keeping event, a vehicle is proceeding at a speed that is equal to or more than the threshold value from the rearward direction of a lane which is a lane change destination, the action plan generation unit  106  changes the next event of the lane keeping event from the lane change to a deceleration event, a lane keeping event, or the like. Thereby, the vehicle control apparatus  100  can avoid the vehicle M colliding with the vehicle of the lane change destination. As a result, the vehicle control apparatus  100  can allow the vehicle M to automatically travel safely even when the state of the outside environment is changed. 
     Lane Change Event 
     The lane change control unit  110  performs a control when a lane change event that is included in the action plan by the action plan generation unit  106  is performed. The lane change control unit  110  includes, for example, a target position candidate setting part  111 , a determination part  112 , a virtual vehicle setting part  113 , an another vehicle position change estimation part  114 , a travel trajectory generation part  115 , and a target position determination part  116 . The combination of the determination part  112 , the virtual vehicle setting part  113 , the another vehicle position change estimation part  114 , and the travel trajectory generation part  115  is an example of a control plan generation part. 
     Setting of Target Position Candidate 
     The target position candidate setting part  111  first sets the outline of a target region that becomes a lane change target with reference to the position of the peripheral vehicle that is recognized by the outside recognition unit  104  and sets, in the target region, a lane change target position candidate as a relative position with respect to a peripheral vehicle that is traveling on an adjacent lane which is adjacent to the travel lane (self-lane) on which the vehicle M is traveling. In the present embodiment, an example in which the target region corresponds to the entire detection region of a device is described. The target region may be a partial region of the detection region of the device. 
       FIG. 5  is a view showing a state in which the target position candidate setting part  111  in the first embodiment sets a lane change target position candidate. In the drawing, “ma”, “mb” represent a peripheral vehicle, “d” represents a proceeding (travel) direction of each vehicle, “L 1 ” represents a travel lane, and “L 2 ”, “L 3 ” represent an adjacent lane. “DR” represents a detection region, and “T 1 ” to “T 3 ” represent a lane change target position candidate. When the lane change target position candidates are not specifically distinguished, the lane change target position candidates are represented simply as a lane change target position candidate T. 
     In the case of an example of  FIG. 5 , the target position candidate setting part  111  sets the lane change target position candidate T 1  between the vehicle ma and the vehicle mb on the adjacent lane L 2  and sets the lane change target position candidate T 2  at a space from a rearward position of the vehicle mb to an outer edge of the detection region DR on the rearward side with respect to the vehicle proceeding direction d. That is, when a plurality of peripheral vehicles are present on the adjacent lane, the target position candidate setting part  111  sets the lane change target position candidate T between the peripheral vehicles. For example, when the number of the peripheral vehicles that are present is n, the number of the lane change target position candidates T that are set in the detection region DR on the adjacent lane by the target position candidate setting part  111  is (n+1). In the example of  FIG. 5 , the frontward position of the vehicle ma is the boundary of the detection region D, and therefore, the target position candidate T cannot be set at the frontward position of the vehicle ma. Accordingly, two vehicles are present on the adjacent lane L 2 , and therefore, the target position candidate setting part  111  needs to set three lane change target position candidates T; however, the target position candidate T cannot be set at the frontward position of the vehicle ma, and therefore, two lane change target position candidates T are set. 
     A peripheral vehicle is not present on the adjacent lane L 3 , and therefore, the target position candidate setting part  111  sets the lane change target position candidate T 3  at a space from a frontward outer edge of the detection region DR with respect to the vehicle proceeding direction d to a rearward outer edge of the detection region DR with respect to the vehicle proceeding direction d on the adjacent lane L 3 . That is, when a peripheral vehicle is not present on the adjacent lane, the target position candidate setting part  111  sets one lane change target position candidate T in the entire detection region DR (in the entire adjacent lane L 3 ) on the adjacent lane. In the following description, unless otherwise specified, it is assumed that the action plan commands to change the lane to the adjacent lane L 2  that extends on the right side of the travel lane L 1 . 
     When a case in which the lane is changed to the lane change target position candidate T that is set by the target position candidate setting part  111  is assumed, the determination part  112  determines whether or not a peripheral vehicle that satisfies a predetermined condition is recognized by the outside recognition unit  104 . 
     A peripheral vehicle that satisfies a predetermined condition being recognized is at least one of: a peripheral vehicle (hereinafter, referred to as a “frontward traveling vehicle”) that is traveling at a frontward position of (immediately before) the vehicle M in the travel lane being recognized by the outside recognition unit  104 ; a peripheral vehicle (hereinafter, referred to as a “lane-change target-position candidate frontward-traveling vehicle”) that is traveling at a frontward position of (immediately before) the lane change target position candidate T that is set by the target position candidate setting part  111  being recognized by the outside recognition unit  104 ; and a peripheral vehicle (hereinafter, referred to as a “lane-change target-position candidate rearward-traveling vehicle”) that is traveling at a rearward position of (immediately after) the lane change target position candidate T that is set by the target position candidate setting part  111  being recognized by the outside recognition unit  104 . 
     When any one or more vehicles of the frontward traveling vehicle, the lane-change target-position candidate frontward-traveling vehicle, and the lane-change target-position candidate rearward-traveling vehicle are not recognized by the outside recognition unit  104 , the virtual vehicle setting part  113  sets a virtual vehicle which virtually simulates an unrecognized vehicle. 
     The another vehicle position change estimation part  114  estimates a future position change with respect to the frontward traveling vehicle, the lane-change target-position candidate frontward-traveling vehicle, and the lane-change target-position candidate rearward-traveling vehicle. In this case, when any one or more vehicles of the frontward traveling vehicle, the lane-change target-position candidate frontward-traveling vehicle, and the lane-change target-position candidate rearward-traveling vehicle are not recognized by the outside recognition unit  104 , the another vehicle position change estimation part  114  estimates a future position change with respect to the vehicle that is recognized by the outside recognition unit  104  of the three vehicles and the virtual vehicle that is set by the virtual vehicle setting part  113  in response to the vehicle being unrecognized. 
     The travel trajectory generation part  115  generates a travel trajectory for a lane change according to the position change of the peripheral vehicle that is estimated by the another vehicle position change estimation part  114  for each lane change target position candidate T that is set by the target position candidate setting part  111 . The travel trajectory is an example of a control plan. 
     The target position determination part  116  determines one lane change target position T# from a plurality of lane change target position candidates T that are set by the target position candidate setting part  111  according to the travel trajectory that is generated for each lane change target position candidate T by the travel trajectory generation part  115 . 
     Hereinafter, a specific process of the lane change control unit  110  is described with reference to a flowchart.  FIG. 6  is a flowchart showing an example of a process flow of the lane change control part  110  in the first embodiment. 
     First, the target position candidate setting part  111  selects one from the lane change target position candidates T (Step S 100 ). Next, when a case in which the lane is changed to the lane change target position candidate T that is selected by the target position candidate setting part  111  is assumed, the determination part  112  determines whether or not the frontward traveling vehicle, the lane-change target-position candidate frontward-traveling vehicle, and the lane-change target-position candidate rearward-traveling vehicle are recognized (detected) by the outside recognition unit  104  (detection part DT) (Step S 102 ). 
     When any one or more vehicles of the frontward traveling vehicle, the lane-change target-position candidate frontward-traveling vehicle, and the lane-change target-position candidate rearward-traveling vehicle are not recognized by the outside recognition unit  104 , the virtual vehicle setting part  113  sets a virtual vehicle which virtually simulates an unrecognized vehicle (Step S 104 ). 
     Hereinafter, a setting process of a virtual vehicle which is the process of Step S 104  is described.  FIG. 7  is a flowchart showing an example of the flow of the setting process of a virtual vehicle. The process of the present flowchart corresponds to the process of Step S 104  in the flowchart of  FIG. 6  described above. 
     First, the determination part  112  determines whether or not a frontward traveling vehicle is recognized by the outside recognition unit  104  (Step S 200 ). In a case where a frontward traveling vehicle is not recognized by the outside recognition unit  104 , the virtual vehicle setting part  113  sets a virtual vehicle which virtually simulates a frontward traveling vehicle in a predetermined state, in the vicinity of the outer edge of the detection region in the frontward direction of the travel lane (Step S 202 ). 
     The predetermined state includes a state in which the speed of the virtual vehicle is zero, a state in which the speed (or acceleration) of the virtual vehicle is equal to or less than a threshold value, and a state in which the speed of the virtual vehicle is the same as the speed of the vehicle M. For example, the virtual vehicle setting part  113  may set a virtual vehicle that is stopping in the vicinity of the outer edge of the detection region DR or may set a virtual vehicle that is slowly traveling at a certain speed. In the present embodiment, the virtual vehicle setting part  113  sets a virtual vehicle as a stationary body that is stopping when a frontward traveling vehicle is not recognized. 
       FIG. 8  is a view showing an example of a scene in which a frontward traveling vehicle is not recognized in the detection region DR. In the example of  FIG. 8 , the travel lane is represented by “L 1 ”, the adjacent lane on the right side of the travel lane L 1  is represented by “L 2 ”, the adjacent lane on the left side of the travel lane L 1  is represented by “L 3 ”, and the lane change target position candidate is represented by “T”. In the example of  FIG. 8 , the peripheral vehicle m 2  is located at a frontward position of the lane change target position candidate T in the adjacent lane L 2  and is therefore recognized as the lane-change target-position candidate frontward-traveling vehicle. The peripheral vehicle m 3  is located at a rearward position of the lane change target position candidate T in the adjacent lane L 2  and is therefore recognized as the lane-change target-position candidate rearward-traveling vehicle. A vehicle that is located at a frontward position of the vehicle M in the travel lane L 1  is not detected, and therefore, the frontward traveling vehicle is not recognized. Accordingly, the virtual vehicle setting part  113  sets a virtual vehicle vm as a stationary body in the vicinity of the outer edge of the detection region DR in the frontward direction of the travel lane L 1 . 
     Specifically, the virtual vehicle setting part  113  sets a virtual vehicle such that a rear end part of the vehicle body is located on the outside of the detection region DR.  FIG. 9  is a view showing an example of a state in which the virtual vehicle vm is set in the vicinity of the outer edge of the detection region DR. As shown in  FIG. 9 , the virtual vehicle setting part  113  arranges the virtual vehicle on the outside of the outer edge such that the entire vehicle body region is not included in the detection region DR. 
     The virtual vehicle setting part  113  may set a virtual vehicle such that the rear end part of the vehicle body is located on the inside of the detection region DR.  FIG. 10  is a view showing another example of the state in which the virtual vehicle vm is set in the vicinity of the outer edge of the detection region DR. As shown in  FIG. 10 , the virtual vehicle setting part  113  arranges the virtual vehicle on the outer edge such that part of the vehicle body region is included in the detection region DR. The virtual vehicle setting part  113  may arrange the virtual vehicle on the inside of the outer edge such that the entire vehicle body region is included in the detection region DR. The virtual vehicle setting part  113  sets the virtual vehicle, for example, at a center CL of the travel lane regarding the lane width direction with respect to the lane proceeding direction. The virtual vehicle setting part  113  may set the virtual vehicle at a position that is away from the center CL regarding the lane width direction. 
     Next, the determination part  112  determines whether or not the lane-change target-position candidate frontward-traveling vehicle is recognized by the outside recognition unit  104  (Step S 204 ). In a case where the lane-change target-position candidate frontward-traveling vehicle is not recognized by the outside recognition unit  104 , the virtual vehicle setting part  113  sets a virtual vehicle which virtually simulates the unrecognized lane-change target-position candidate frontward-traveling vehicle in a predetermined state, in the vicinity of the outer edge of the detection region in the frontward direction of the adjacent lane (Step S 206 ). In the present embodiment, similarly to a case where a virtual vehicle which virtually simulates a frontward traveling vehicle is set, the virtual vehicle setting part  113  sets a virtual vehicle which virtually simulates the lane-change target-position candidate frontward-traveling vehicle in a still state. 
       FIG. 11  is a view showing an example of a scene in which a lane-change target-position candidate frontward-traveling vehicle is not recognized in the detection region DR. In the example of  FIG. 11 , similarly to  FIG. 8 , the travel lane is represented by “L 1 ”, the adjacent lane on the right side of the travel lane L 1  is represented by “L 2 ”, the adjacent lane on the left side of the travel lane L 1  is represented by “L 3 ”, and the lane change target position candidate is represented by “T”. In the example of  FIG. 11 , the peripheral vehicle m 1  is located at a frontward position of the vehicle M in the travel lane L 1  and is therefore recognized as the frontward traveling vehicle. The peripheral vehicle m 3  is located at a rearward position of the lane change target position candidate T in the adjacent lane L 2  and is therefore recognized as the lane-change target-position candidate rearward-traveling vehicle. A vehicle that is located at a frontward position of the lane change target position candidate T in the adjacent lane L 2  is not detected, and therefore, the lane-change target-position candidate frontward-traveling vehicle is not recognized. Accordingly, the virtual vehicle setting part  113  sets a virtual vehicle vm which virtually simulates the lane-change target-position candidate frontward-traveling vehicle as a stationary body, in the vicinity of the outer edge of the detection region DR in the frontward direction of the adjacent lane L 2 . 
     The arrangement position of the virtual vehicle vm that is set in the vicinity of the outer edge of the detection region DR when the lane-change target-position candidate frontward-traveling vehicle is not recognized is similar to that of the case in which the virtual vehicle of the frontward traveling vehicle is arranged as described above. For example, the virtual vehicle setting part  113  may set a virtual vehicle such that a rear end part of the vehicle body is located on the outside of the detection region DR or may set a virtual vehicle such that a rear end part of the vehicle body is located on the inside of the detection region DR. 
     Next, the determination part  112  determines whether or not the lane-change target-position candidate rearward-traveling vehicle is recognized by the outside recognition unit  104  (Step  208 ). In a case where the lane-change target-position candidate rearward-traveling vehicle is not recognized by the outside recognition unit  104 , the virtual vehicle setting part  113  sets a virtual vehicle which virtually simulates the unrecognized lane-change target-position candidate rearward-traveling vehicle in a movable state (as a movable body), in the vicinity of the outer edge of the detection region DR in the frontward direction of the adjacent lane (Step S 210 ). 
     The movable state includes a state in which the speed (or acceleration) of the virtual vehicle is a threshold value or more. 
     For example, the virtual vehicle setting part  113  may set a virtual vehicle that travels at a speed of constant number of times (including one time) of the maximum speed possible, in the vicinity of the outer edge of the detection region DR or may set a virtual vehicle that is traveling at a speed of constant times (including one time) of the speed of the vehicle M or the lane-change target-position candidate frontward-traveling vehicle. In the present embodiment, the virtual vehicle setting part  113  sets the virtual vehicle as a movable body that is traveling at a possible maximum speed. 
       FIG. 12  is a view showing an example of a scene in which the lane-change target-position candidate rearward-traveling vehicle is not recognized in the detection region DR. In the example of  FIG. 12 , similarly to  FIG. 8  and  FIG. 11 , the travel lane is represented by “L 1 ”, the adjacent lane on the right side of the travel lane L 1  is represented by “L 2 ”, the adjacent lane on the left side of the travel lane L 1  is represented by “L 3 ”, and the lane change target position candidate is represented by “T”. In the example of  FIG. 12 , the peripheral vehicle m 1  is located at a frontward position of the vehicle M in the travel lane L 1  and is therefore recognized as the frontward traveling vehicle. The peripheral vehicle m 2  is located at a frontward position of the lane change target position candidate T in the adjacent lane L 2  and is therefore recognized as the lane-change target-position candidate frontward-traveling vehicle. A vehicle that is located at a rearward position of the lane change target position candidate T in the adjacent lane L 2  is not detected, and therefore, the lane-change target-position candidate rearward-traveling vehicle is not recognized. Accordingly, the virtual vehicle setting part  113  sets a virtual vehicle vm which virtually simulates the lane-change target-position candidate rearward-traveling vehicle as a stationary body, in the vicinity of the outer edge of the detection region DR in the rearward direction of the adjacent lane L 2 . 
     The arrangement position of the virtual vehicle vm that is set in the vicinity of the outer edge of the detection region DR when the lane-change target-position candidate rearward-traveling vehicle is not recognized is similar to the arrangement position of the virtual vehicle in the case of the frontward traveling vehicle or the lane-change target-position candidate frontward-traveling vehicle described above. For example, the virtual vehicle setting part  113  may set a virtual vehicle such that a front end part of the vehicle body is located on the outside of the detection region DR or may set a virtual vehicle such that a front end part of the vehicle body is located on the inside of the detection region DR. 
     According to the process of the flowchart described above, it is possible to set a virtual vehicle for each peripheral vehicle that satisfies a predetermined condition. 
     The flowchart of  FIG. 6  is described. When the frontward traveling vehicle, the lane-change target-position candidate frontward-traveling vehicle, and the lane-change target-position candidate rearward-traveling vehicle are recognized by the outside recognition unit  104  in the process of Step S 102 , the another vehicle position change estimation part  114  estimates a future position change with respect to the frontward traveling vehicle, the lane-change target-position candidate frontward-traveling vehicle, and the lane-change target-position candidate rearward-traveling vehicle that are recognized by the outside recognition unit  104 , in a state where a virtual vehicle is not set (Step S 106 ). 
     It is possible to estimate the future position change, for example, according to a constant speed model in which it is assumed that a vehicle travels while keeping the current speed, a constant acceleration model in which it is assumed that a vehicle travels while keeping the current acceleration, or a variety of other models. The another vehicle position change estimation part  114  may consider the steering angle of a peripheral vehicle (including a virtual vehicle) with which the vehicle M will interfere with a high chance when changing a lane or may assume that the peripheral vehicle travels while keeping the current travel lane to estimate the position change without considering the steering angle. In the following description, it is assumed that the peripheral vehicle travels while keeping the current speed and maintaining the travel lane to estimate the position change. 
       FIG. 13  is a view showing an example of, in a case where a peripheral vehicle that becomes a determination target is recognized, a positional relationship between the vehicle M and the peripheral vehicle. In  FIG. 13 , “M” represents a vehicle, the peripheral vehicle m 1  represents a frontward traveling vehicle, the peripheral vehicle m 2  represents a lane-change target-position candidate frontward-traveling vehicle, the peripheral vehicle m 3  represents a lane-change target-position candidate rearward-traveling vehicle, and “T” represents the lane change target position candidate. For example, Pattern (a) represents a positional relationship of m 1 -m 2 -M-m 3  in the order from the vehicle proceeding direction and shows an example in which the vehicle M changes the lane without changing the relative position with the peripheral vehicle. Pattern (b) represents a positional relationship of m 2 -m 1 -m 3 -M in the order from the vehicle proceeding direction and shows an example in which the vehicle M changes the lane while advancing (relatively accelerating) the relative position with the peripheral vehicle. 
     For example, the another vehicle position change estimation part  114  categorizes the future position change according to speed models of the peripheral vehicles m 1 , m 2 , and m 3  for each pattern in which the vehicle positional relationship is categorized. 
       FIG. 14  is a view showing patterns into which the position change of the peripheral vehicle is categorized with respect to Pattern (a) of the vehicle positional relationship.  FIG. 15  is a view showing patterns into which the position change of the peripheral vehicle is categorized with respect to Pattern (b) of the vehicle positional relationship. The vertical axis in  FIG. 14  and  FIG. 15  represents a displacement with respect to the proceeding direction with reference to the vehicle M, and the horizontal axis represents an elapsed time. A lane-change-subsequent presence-available region in  FIG. 14  and  FIG. 15  shows a displacement region in which the vehicle M is capable of being present after performing a lane change when the peripheral vehicle (m 1 , m 2 , m 3 ) that becomes the determination target keeps traveling in the same trend. For example, a drawing indicated by “speed: m 2 &gt;m 1 &gt;m 3 ” in  FIG. 14  shows that the lane change available region is on a more lower side than the displacement of the frontward traveling vehicle m 1 , that is, although the vehicle M is restricted so as not to be a more frontward position than the frontward traveling vehicle m 1  before performing a lane change, it is no problem for the vehicle M to be a more frontward position than the frontward traveling vehicle m 1  after performing a lane change. The lane-change-subsequent presence-available region is used for the process of the travel trajectory generation part  115 . The pattern in which the vehicle positional relationship is categorized may be, for example, a positional relationship such as “m 2 -m 1 -M-m 3 ” and “m 1 -M-m 2 -m 3 ” in addition to Patterns (a), (b) described above or may be categorized depending on the number of vehicles. In the example described above, the pattern that represents the vehicle positional relationship is categorized into six patterns. 
     When any one or more vehicles of the frontward traveling vehicle, the lane-change target-position candidate frontward-traveling vehicle, and the lane-change target-position candidate rearward-traveling vehicle are not recognized by the outside recognition unit  104 , and a virtual vehicle is set in the process of Step S 102  described above, the another vehicle position change estimation part  114  estimates a future position change with respect to the frontward traveling vehicle, the lane-change target-position candidate frontward-traveling vehicle, or the lane-change target-position candidate rearward-traveling vehicle that are recognized by the outside recognition unit  104  and the virtual vehicle that is set by the virtual vehicle setting part  113  in response to being not recognized (Step S 106 ). 
     For example, when the lane-change target-position candidate frontward-traveling vehicle and the lane-change target-position candidate rearward-traveling vehicle are recognized, and the frontward traveling vehicle is not recognized, the another vehicle position change estimation part  114  estimates a future position change with respect to the lane-change target-position candidate frontward-traveling vehicle and the lane-change target-position candidate rearward-traveling vehicle that are recognized and a virtual vehicle that virtually simulates the unrecognized frontward traveling vehicle. 
       FIG. 16  is a view showing an example of, in a case where part of a peripheral vehicle that becomes a determination target is not recognized, a positional relationship between the vehicle M and the peripheral vehicle. In the example of  FIG. 16 , a frontward traveling vehicle m 1  is not recognized, and a virtual vehicle vm 1  that virtually simulates the frontward traveling vehicle m 1  is set. Hereinafter, a vehicle positional relationship when a virtual vehicle vm 1  is set is described as Pattern (c). For example, Pattern (c) represents a positional relationship of vm 1 -m 2 -M-m 3  in the order from the vehicle proceeding direction and shows an example in which the vehicle M changes the lane without changing the relative position with the peripheral vehicle. 
     In the case of the positional relationship of Pattern (c), the another vehicle position change estimation part  114  categorizes the future position change according to speed models of the virtual vehicle vm 1 , the lane-change target-position candidate frontward-traveling vehicle m 2 , and the lane-change target-position candidate rearward-traveling vehicle m 3 .  FIG. 17  is a view showing patterns into which the position change of the peripheral vehicle is categorized with respect to Pattern (c) of the vehicle positional relationship. 
     The vertical axis in  FIG. 17  represents a displacement with respect to the proceeding direction with reference to the vehicle M, and the horizontal axis represents an elapsed time, similarly to  FIG. 14  and  FIG. 15 . In the example of  FIG. 17 , the future position change is estimated using a model in which the virtual vehicle vm 1  is assumed to be a stationary body having a speed of zero. 
     When all of the frontward traveling vehicle, the lane-change target-position candidate frontward-traveling vehicle, and the lane-change target-position candidate rearward-traveling vehicle are not recognized by the outside recognition unit  104 , the another vehicle position change estimation part  114  estimates a future position change with respect to virtual vehicles that correspond to all of these peripheral vehicles. In such a case, the another vehicle position change estimation part  114  estimates a future position change according to a speed model in accordance with the speed of each virtual vehicle that is set by the virtual vehicle setting part  113 . 
     The vehicle that is taken into consideration is not limited to the frontward traveling vehicle, the lane-change target-position candidate frontward-traveling vehicle, and the lane-change target-position candidate rearward-traveling vehicle described above; and, for example, the another vehicle position change estimation part  114  may take a vehicle that is traveling on the travel lane and that is different from the above-described frontward traveling vehicle or a vehicle that is traveling on the adjacent lane and that is different from the above-described lane-change target-position candidate frontward-traveling vehicle and the above-described lane-change target-position candidate rearward-traveling vehicle into consideration and estimate a future position change. The another vehicle position change estimation part  114  may take a peripheral vehicle that is traveling on a further adjacent lane of the adjacent lane and estimate a future position change. 
     Next, the travel trajectory generation part  115  generates a travel trajectory for a lane change according to the position change of the peripheral vehicle that is estimated by the another vehicle position change estimation part  114  for each lane change target position candidate T that is set by the target position candidate setting part  111  (Step S 108 ). 
     The process of Step S 108  is described. In the following description, an example of a speed relationship of m 1 &gt;m 3 &gt;m 2  in Pattern (b) of the above-described vehicle positional relationship is described. For example, the travel trajectory generation part  115  determines a start time point and an end time point of a lane change according to the position change of the peripheral vehicle that is estimated by the another vehicle position change estimation part  114  and determines the speed of the vehicle M such that a lane change is performed in a period (lane change available period P) from the start time point to the end time point. In order to determine the start time point of the lane change, a parameter such as “a time point when the vehicle M overtakes the lane-change target-position candidate rearward-traveling vehicle m 3 ” is present, and in order to obtain this, an assumption regarding the acceleration or deceleration of the vehicle M is required. With respect to this point, for example, if accelerating, the travel trajectory generation part  115  derives a speed change curve using the legal speed as the upper limit in a range where the acceleration from the current speed of the vehicle M does not become an abrupt acceleration and determines “the time point when the vehicle M overtakes the lane-change target-position candidate rearward-traveling vehicle m 3 ” by using the derived speed change curve together with the position change of the lane-change target-position candidate rearward-traveling vehicle m 3 . Thereby, the travel trajectory generation part  115  determines the start time point of the lane change. 
     In order to determine the end time point of the lane change, the travel trajectory generation part  115  determines as the end time point, for example, when the lane-change target-position candidate rearward-traveling vehicle m 3  catches up with the lane-change target-position candidate frontward-traveling vehicle m 2 , and the distance between the lane-change target-position candidate rearward-traveling vehicle m 3  and the lane-change target-position candidate frontward-traveling vehicle m 2  becomes a predetermined distance. In this way, the travel trajectory generation part  115  determines the start time point and the end time point of the lane change and thereby derives the lane change available period P. 
     The travel trajectory generation part  115  obtains a limitation of the speed of the vehicle M at which the vehicle M is capable of entering the lane change available region in the derived lane change available period P and generates a travel trajectory used for the lane change in accordance with the limitation of the speed.  FIG. 18  is a view showing an example of the travel trajectory used for the lane change that is generated by the travel trajectory generation part  115 . The vertical axis in  FIG. 18  represents a displacement with respect to the proceeding direction with reference to the vehicle M, and the horizontal axis represents an elapsed time. The frontward traveling vehicle is represented by “m 1 ”, the lane-change target-position candidate frontward-traveling vehicle is represented by “m 2 ”, and the lane-change target-position candidate rearward-traveling vehicle is represented by “m 3 ”. In the example of  FIG. 18 , the lane change available region is a region that is smaller than the displacement of both the frontward traveling vehicle m 1  and the lane-change target-position candidate frontward-traveling vehicle m 2  and that is larger than the displacement of the lane-change target-position candidate rearward-traveling vehicle m 3 . That is, the limitation of the speed of the vehicle M is set in a speed range in which the vehicle M does not catch up with the frontward traveling vehicle m 1  and overtakes the lane-change target-position candidate rearward-traveling vehicle m 3  in the period (lane change available period P) until the lane-change target-position candidate rearward-traveling vehicle m 3  catches up with the lane-change target-position candidate frontward-traveling vehicle m 2 . 
     The limitation of the speed of the vehicle M may include traveling so as to follow up the lane-change target-position candidate frontward-traveling vehicle m 2  which becomes a frontward traveling vehicle after the lane change (in a state of being located at a position between the lane-change target-position candidate frontward-traveling vehicle m 2  and the lane-change target-position candidate rearward-traveling vehicle m 3 ). 
     In this case, at a time point when the follow-up travel is started, the vehicle M may be deviated from the lane change available region and enter a lane-change-subsequent presence-available region. As shown in  FIG. 18 , the lane-change-subsequent presence-available region is a region in which the displacement of the frontward traveling vehicle m 1  is smaller than the displacement of the lane-change target-position candidate frontward-traveling vehicle m 2 . That is, entering the lane-change-subsequent presence-available region from the lane change available region represents a transition from when maintaining a state in which the vehicle M does not come to a more frontward position than the frontward traveling vehicle m 1  according to the limitation of the speed described above before performing the lane change to a state the vehicle M comes to a more frontward position than the frontward traveling vehicle m 1  after performing the lane change. 
     Further, when it is necessary to perform a lane change after the vehicle M overtakes the lane-change target-position candidate rearward-traveling vehicle m 3 , the travel trajectory generation part  115  sets the limitation of the speed of the vehicle M such that the lane change is started at a point (for example, CP in the drawing) where the displacement of the vehicle M is sufficiently larger than the displacement of the lane-change target-position candidate rearward-traveling vehicle m 3 . The travel trajectory generation part  115  draws a trajectory (track) that represents the change of the displacement of the vehicle M indicated in the drawing such that the limitation of the speed that is set in this way is satisfied and derives the trajectory as a travel trajectory. The travel trajectory generation part  115  may generate, for example, a travel trajectory by which a frontward traveling vehicle is followed up at a speed at which the relative position to the frontward traveling vehicle is constant. 
     The lane change control unit  110  determines whether or not the process of Step S 100  to S 108  is performed with respect to all of the lane change target position candidates T (Step S 110 ). When the process of Steps S 100  to S 108  is not performed with respect to all of the lane change target position candidates T, the routine returns to Step S 100 , the next lane change target position candidate T is selected to perform the subsequent process. 
     When the process of Steps S 100  to S 108  is performed with respect to all of the lane change target position candidates T, the target position determination part  116  evaluates corresponding travel trajectories and thereby determines the lane change target position T# (Step S 112 ). 
     The target position determination part  116  determines the lane change target position T#, for example, from the viewpoint of safety or efficiency. The target position determination part  116  refers to the travel trajectory that corresponds to each of the lane change target position candidates T and preferentially selects one in which the spacing with the frontward and rearward vehicles at the time of the lane change is large, one in which the speed is close to the legal speed, one in which acceleration or deceleration that is required at the time of the lane change is small, or the like as the lane change target position T#. In this way, one lane change target position T# and one travel trajectory are determined. 
     According to the process sequence described above, the process of the present flowchart is finished. 
     Travel Control 
     The travel control part  120  sets a control mode to an automated driving mode or a manual driving mode according to a control by the control switch unit  122  and controls a control target that includes part of or all of the travel drive force output device  72 , the steering device  74 , and the brake device  76  in accordance with the set control mode. The travel control part  120  reads the action plan information  136  that is generated by the action plan generation unit  106  at the automated driving mode and controls the control target according to the event that is included in the read action plan information  136 . When the event is a lane change event, the travel control part  120  determines the control amount (for example, a rotation number) of the electric motor in a steering device  92  and the control amount (for example, a throttle opening degree of an engine, a shift step, and the like) of the ECU in a travel drive force output device  90  in accordance with the travel trajectory that is generated by the travel trajectory generation part  115 . The travel control part  120  outputs information indicating the control amount that is determined for each event to the corresponding control target. Thereby, each device ( 72 ,  74 ,  76 ) as a control target can control the device as the control target in accordance with the information indicating the control amount that is input from the travel control part  120 . 
     Further, the travel control part  120  appropriately adjusts the determined control amount according to a detection result of the vehicle sensor  60 . 
     The travel control part  120  controls the control target according to an operation detection signal that is output by the operation detection sensor  80  at the manual driving mode. For example, the travel control part  120  outputs the operation detection signal that is output by the operation detection sensor  80  as is to each device as the control target. 
     The control switch unit  122  switches the control mode of the vehicle M by the travel control part  120  from the automated driving mode to the manual driving mode or from the manual driving mode to the automated driving mode according to the action plan information  136  that is generated by the action plan generation unit  106  and that is stored in the storage part  130 . The control switch unit  122  switches the control mode of the vehicle M by the travel control part  120  from the automated driving mode to the manual driving mode or from the manual driving mode to the automated driving mode according to the control mode designation signal that is input from the switch  82 . That is, the control mode of the travel control part  120  can be arbitrarily changed while traveling or stopping by the operation of the driver or the like. 
     The control switch unit  122  switches the control mode of the vehicle M by the travel control part  120  from the automated driving mode to the manual driving mode according to the operation detection signal that is input from the operation detection sensor  80 . For example, the control switch unit  122  switches the control mode of the travel control part  120  from the automated driving mode to the manual driving mode when the operation amount that is included in the operation detection signal exceeds a threshold value, that is, when an operation device  70  accepts an operation by the operation amount that exceeds the threshold value. For example, the control switch unit  122  switches the control mode of the travel control part  120  from the automated driving mode to the manual driving mode when the steering wheel, the accelerator pedal, or the brake pedal is operated by the operation amount that exceeds the threshold value by the driver in a case where the vehicle M is automatically traveling by the travel control part  120  that is set in the automated driving mode. Thereby, the vehicle control apparatus  100  can switch the driving mode to the manual driving mode immediately via no operation of the switch  82  by an operation that is abruptly performed by the driver when an object such as a person dashes out to the road or when a frontward traveling vehicle suddenly stops. As a result, the vehicle control apparatus  100  can respond to an operation in an emergency by the driver, and it is possible to enhance safety when traveling. 
     According to the vehicle control apparatus  100 , the vehicle control method, and the vehicle control program in the first embodiment described above, the virtual vehicle setting part  113  generates a travel trajectory of a vehicle according to a peripheral vehicle that satisfies a predetermined condition among one or more peripheral vehicles that are detected by the detection part DT, and when it is not possible to detect the peripheral vehicle that satisfies the predetermined condition, a virtual vehicle which virtually simulates the peripheral vehicle that satisfies the predetermined condition is set, and the travel trajectory of the vehicle is generated. Thereby, even when it is not possible to detect the peripheral vehicle that satisfies the predetermined condition by the detection part DT, it is possible to accurately estimate the future position change of the peripheral vehicle at the time of a lane change. Thereby, in the vehicle control apparatus  100  in the first embodiment, the travel control part  120  can accurately control acceleration, deceleration, or steering of the vehicle according to one or both of the virtual vehicle that is set by the virtual vehicle setting part  113  and the peripheral vehicle that is detected by the detection part DT. As a result, it is possible for the vehicle control apparatus  100  in the first embodiment to perform further flexible automated driving. 
     Further, according to the vehicle control apparatus  100 , the vehicle control method, and the vehicle control program in the first embodiment, any one or more vehicles among the frontward traveling vehicle, the lane-change target-position candidate frontward-traveling vehicle, and the lane-change target-position candidate rearward-traveling vehicle are focused on to perform the lane change, and therefore, it is possible to reduce the cost of calculating the state estimation of the peripheral vehicle which is performed when performing automated driving. 
     Further, according to the vehicle control apparatus  100 , the vehicle control method, and the vehicle control program in the first embodiment, the virtual vehicle that is set in the frontward direction of the vehicle M is a stationary body, or the virtual vehicle that is set in the rearward direction of the vehicle M is a movable body. Therefore, it is possible to perform automated driving further safely. 
     Second Embodiment 
     Hereinafter, a second embodiment is described. A vehicle control apparatus  100  in the second embodiment is different from the vehicle control apparatus  100  of the first embodiment in that when a disappearance region or an appearance region of a lane is detected by the detection part DT, a virtual vehicle is set. Hereinafter, such a difference is mainly described. 
     A detection part DT in the second embodiment is a combination of the finder  20 , the radar  30 , the camera  40 , the outside recognition unit  104 , and the navigation device  50 . The detection part DT in the second embodiment detects a disappearance region or an appearance region of a lane according to one or both of the detection result of a device and the map information  132  that is stored in the storage unit  130 . More specifically, the outside recognition unit  104  that is included in the detection part DT recognizes a disappearance region or an appearance region of a lane according to one or both of the detection result of a device and the map information  132  that is stored in the storage unit  130 . For example, the disappearance region of a lane is a lane merging point, and the appearance region of a lane is a lane branching point. In the following description, the disappearance region or the appearance region of a lane being recognized by the outside recognition unit  104  is described as the disappearance region or the appearance region of a lane being detected by the detection part DT. The detection part DT in the second embodiment is an example of a “second detection part”. 
     In the second embodiment, the determination part  112  determines whether or not the disappearance region or the appearance region of a lane is detected by the detection part DT. 
     Hereinafter, a case in which a disappearance region of a lane is detected is described.  FIG. 19  is a flowchart showing an example of a process flow of a lane change control part  110  in the second embodiment. For example, the lane change control part  110  sets a virtual vehicle when a disappearance region of a lane is present in accordance with the process of the present flowchart. The process of the present flowchart corresponds to the process of Step S 200  and S 202  in  FIG. 7  described above. 
     First, the determination part  112  determines whether or not a frontward traveling vehicle is present in the detection region DR, that is, whether or not a frontward traveling vehicle is recognized by the outside recognition unit  104  (Step S 300 ). 
     The lane change control unit  110  finishes the process of the present flowchart when a frontward traveling vehicle is present in the detection region DR. 
     On the other hand, when a frontward traveling vehicle is not present in the detection region DR, the determination part  112  determines whether or not the disappearance region of a lane is detected in the detection region DR (Step S 302 ). When the disappearance region of a lane is not detected in the detection region DR, the virtual vehicle setting part  113  sets a virtual vehicle which virtually simulates a frontward traveling vehicle in the vicinity of the outer edge of the detection region DR, similarly to the first embodiment described above (Step S 304 ). 
     On the other hand, when the disappearance region of a lane is detected in the detection region DR, the virtual vehicle setting part  113  sets a virtual vehicle which virtually simulates a frontward traveling vehicle in the vicinity of the disappearance region of the lane (Step S 306 ). 
       FIG. 20  is a view showing an example of a scene in which a disappearance region of a lane is detected in a detection region DR. In the example of  FIG. 20 , a peripheral vehicle m 2  is recognized as the lane-change target-position candidate frontward-traveling vehicle, and a peripheral vehicle m 3  is recognized as the lane-change target-position candidate rearward-traveling vehicle. A frontward traveling vehicle is not recognized, and the lane disappears on the travel lane L 1 . In such a case, the virtual vehicle setting part  113  sets a virtual vehicle vm in a region in which a width W of the travel lane L 1  is narrowed in the detection region DR. More specifically, the virtual vehicle setting part  113  sets the virtual vehicle vm in a range A 1  from a position at which the width W of the travel lane L 1  starts to be reduced to a position at which the lane completely disappears. When an outer edge of the detection region DR is included in the range A 1 , the virtual vehicle setting part  113  sets the virtual vehicle vm in a range A 1 # from a position at which the width W of the travel lane L 1  starts to be reduced to the outer edge of the detection region DR. The virtual vehicle setting part  113  sets the virtual vehicle vm as a stationary body (speed of zero) in the present embodiment. The virtual vehicle setting part  113  may set a vehicle having a speed (or acceleration) that is equal to or less than a threshold value as the virtual vehicle vm, similarly to the first embodiment described above. 
     Thereby, the process of the present flowchart is finished. As a result, the another vehicle position change estimation part  114  estimates a future position change, for example, with respect to the recognized lane-change target-position candidate frontward-traveling vehicle m 2 , the recognized lane-change target-position candidate rearward-traveling vehicle m 3 , and the virtual vehicle vm which virtually simulates the frontward traveling vehicle and which is set in the vicinity of the disappearance region of the lane. 
     Hereinafter, a case in which an appearance region of a lane is detected is described.  FIG. 21  is a flowchart showing another example of the process flow of the lane change control part  110  in the second embodiment. For example, the lane change control part  110  sets a virtual vehicle when an appearance region of a lane is present in accordance with the process of the present flowchart. The process of the present flowchart corresponds to the process of Step S 208  and S 210  in  FIG. 7  described above. 
     First, the determination part  112  determines whether or not a lane-change target-position candidate rearward-traveling vehicle is present in the detection region DR, that is, whether or not a lane-change target-position candidate rearward-traveling vehicle is recognized by the outside recognition unit  104  (Step S 400 ). The lane change control unit  110  finishes the process of the present flowchart when a lane-change target-position candidate rearward-traveling vehicle is present in the detection region DR. 
     On the other hand, when a lane-change target-position candidate rearward-traveling vehicle is not present in the detection region DR, the determination part  112  determines whether or not the appearance region of a lane is detected in the detection region DR (Step S 402 ). When the appearance region of a lane is not detected in the detection region DR, the virtual vehicle setting part  113  sets a virtual vehicle which virtually simulates a lane-change target-position candidate rearward-traveling vehicle in the vicinity of the outer edge of the detection region DR, similarly to the first embodiment described above (Step S 404 ). 
     On the other hand, when the appearance region of a lane is detected in the detection region DR, the virtual vehicle setting part  113  sets a virtual vehicle which virtually simulates a lane-change target-position candidate rearward-traveling vehicle in the vicinity of the appearance region of the lane (Step S 406 ). 
       FIG. 22  is a view showing an example of a scene in which an appearance region of a lane is detected in a detection region DR. In the example of  FIG. 22 , a peripheral vehicle m 1  is recognized as the frontward traveling vehicle, and a peripheral vehicle m 2  is recognized as a lane-change target-position candidate frontward-traveling vehicle. An adjacent lane L 2  appears from a point of the travel lane L 1 . A vehicle is not present before the lane appears, and therefore, a lane-change target-position candidate rearward-traveling vehicle is not recognized. In such a case, the virtual vehicle setting part  113  sets a virtual vehicle vm in a region in which a width W of the adjacent lane L 2  is broadened in the detection region DR. More specifically, the virtual vehicle setting part  113  sets the virtual vehicle vm in a range A 2  from a position at which the width W of the adjacent lane L 2  starts to be enlarged to a position at which the lane completely appears. At this time, the virtual vehicle setting part  113  sets the virtual vehicle vm as a movable body. 
     Thereby, the process of the present flowchart is finished. As a result, the another vehicle position change estimation part  114  estimates a future position change, for example, with respect to the recognized frontward traveling vehicle m 1 , the recognized lane-change target-position candidate frontward-traveling vehicle m 2 , and the virtual vehicle vm which virtually simulates the lane-change target-position candidate rearward-traveling vehicle and which is set in the vicinity of the appearance region of the lane. 
     According to the vehicle control apparatus  100 , the vehicle control method, and the vehicle control program in the second embodiment described above, when a disappearance region of a lane or an appearance region of a lane is present, the virtual vehicle is set, and thereby, it is possible to perform further flexible automated driving in response to the travel lane. 
     Further, according to the vehicle control apparatus  100 , the vehicle control method, and the vehicle control program in the second embodiment, in a case where the virtual vehicle that is set when the disappearance region of a lane is present is a stationary body, and the virtual vehicle that is set when the disappearance region of a lane is present is a movable body, it is possible to perform automated driving further safely. 
     Third Embodiment 
     Hereinafter, a third embodiment is described. A vehicle control apparatus  100  in the third embodiment is different from the vehicle control apparatus  100  of the first and second embodiments in that when an occlusion occurs in a detection region, the virtual vehicle is set. Hereinafter, such a difference is mainly described. The occlusion is defined as a state in which a peripheral vehicle is possibly present and cannot be detected by being hidden by another vehicle or an object. 
       FIG. 23  is a function configuration view of the vehicle M focusing on the vehicle control apparatus  100  according to the third embodiment. A detection part DT in the third embodiment is a combination of the finder  20 , the radar  30 , the camera  40 , the outside recognition unit  104 , and the navigation device  50 . 
     The detection part DT in the third embodiment detects an occlusion in a detection region of a device according to any one or both of the detection result of the device and the map information  132  that is stored in the storage unit  130 . More specifically, the outside recognition unit  104  that is included in the detection part DT recognizes an occlusion in the detection region of the device according to one or both of the detection result of the device and the map information  132  that is stored in the storage unit  130 . In the following description, an occlusion being recognized by the outside recognition unit  104  is described as an occlusion being detected by the detection part DT. The detection part DT in the third embodiment is an example of a “third detection part”. 
     The vehicle control apparatus  100  according to the third embodiment includes an inter-vehicle distance control unit  140 . The inter-vehicle distance control unit  140  includes a determination part  141 , a virtual vehicle setting part  142 , and a travel trajectory generation part  143 . The determination part  141  determines whether or not an occlusion is detected by the detection part DT. 
     When the determination part  141  determines that an occlusion is detected by the detection part DT, the virtual vehicle setting part  142  sets a virtual vehicle in the vicinity of the region in which the occlusion occurs. 
     The travel trajectory generation part  143  assumes that a frontward traveling vehicle is traveling at a constant speed and generates a travel under a limitation of a speed at which the frontward traveling vehicle is followed up while maintaining the inter-vehicle distance with the frontward traveling vehicle to be constant. 
       FIG. 24  is a flowchart showing an example of a process flow of the inter-vehicle distance control unit  140  in the third embodiment. The process of the present flowchart is performed, for example, in a state where the vehicle M is controlled such that it is assumed that a frontward traveling vehicle is traveling at a constant speed, and the frontward traveling vehicle is followed up while maintaining the inter-vehicle distance with the frontward traveling vehicle to be constant. Hereinafter, such a control in which the frontward traveling vehicle is followed up is referred to as a follow-up travel. 
     First, the determination part  141  determines whether or not a frontward traveling vehicle is present in the detection region DR, that is, whether or not a frontward traveling vehicle is recognized by the outside recognition unit  104  (Step S 500 ). 
     The inter-vehicle distance control unit  140  continues the follow-up travel when a frontward traveling vehicle is present in the detection region DR (Step S 506 ). 
     On the other hand, when a frontward traveling vehicle is not present in the detection region DR, the determination part  141  determines whether or not an occlusion occurs in the detection region DR (Step S 502 ). When an occlusion does not occur in the detection region DR, the virtual vehicle setting part  142  sets a virtual vehicle which virtually simulates a frontward traveling vehicle in the vicinity of the outer edge of the detection region DR (Step S 508 ). Next, the inter-vehicle distance control unit  140  continues the follow-up travel such that the virtual vehicle which is set in the vicinity of the outer edge of the detection region DR is a target (Step S 506 ). 
     On the other hand, when an occlusion occurs in the detection region DR, the virtual vehicle setting part  142  sets a virtual vehicle which virtually simulates a frontward traveling vehicle around the occlusion region (Step S 504 ). 
       FIG. 25  is a view showing an example of a scene in which an occlusion occurs in the detection region DR. In the example of  FIG. 25 , when a frontward traveling vehicle that is traveling on the travel lane L 1  enters a curve road, light by the finder  20 , electric waves by the radar  30 , and the like are blocked by a screening object such as a soundproof wall that is provided on the curve road, and therefore, the subsequent vehicle M cannot recognize the frontward traveling vehicle. 
     In such a case, the virtual vehicle setting part  142  estimates an occlusion region OR according to the area of the detection region DR of the device and the information of the curvature of the curve of the lane, the width of each lane, and the like that are included in the map information  132 . The virtual vehicle setting part  142  estimates an extension line of the travel lane L 1  in accordance with the curvature of the curve and the width of the travel lane L 1  in the occlusion region OR and sets a virtual vehicle vm which virtually simulates a frontward traveling vehicle on the estimated extension line of the travel lane L 1 . That is, when a vehicle to be detected in the detection region is screened according to the occlusion, the virtual vehicle setting part  142  sets a virtual vehicle which virtually simulates the screened vehicle. At this time, the virtual vehicle setting part  142  sets the virtual vehicle vm, for example, as a stationary body (speed of zero). 
     Similarly to the first and second embodiments described above, the virtual vehicle setting part  142  may set, as the virtual vehicle vm, a vehicle having a speed (or acceleration) that is equal to or less than a threshold value or a vehicle having the same speed as the vehicle M. 
     Next, the inter-vehicle distance control unit  140  continues the follow-up travel such that the virtual vehicle which is set around the occlusion region is a target (Step S 506 ). Thereby, the process of the present flowchart is finished. 
     According to the vehicle control apparatus  100 , the vehicle control method, and the vehicle control program in the third embodiment described above, when an occlusion occurs in a detection region, the virtual vehicle is set, and thereby, it is possible to perform further flexible automated driving in accordance with an environment when traveling. For example, even in a case where the vehicle control apparatus  100  in the third embodiment loses sight of a frontward traveling vehicle when performing a follow-up travel in which the frontward traveling vehicle is a target and the like, it is possible to continue performing a control for automated driving. 
     Further, according to the vehicle control apparatus  100 , the vehicle control method, and the vehicle control program in the third embodiment, the virtual vehicle that is set when an occlusion occurs in a detection region is a stationary body, and therefore, it is possible to perform automated driving further safely. 
     Fourth Embodiment 
     Hereinafter, a fourth embodiment is described. A vehicle control apparatus  100  in the fourth embodiment is different from the vehicle control apparatus  100  of the first to third embodiments in that the virtual vehicle is set according to a communication region while an inter-vehicle communication. Hereinafter, such a difference is mainly described. 
       FIG. 26  is a view showing a state in which the vehicle M is performing an inter-vehicle communication while traveling. “CR” indicated in the drawing represents a communication region while an inter-vehicle communication. For example, the outside recognition unit  104  recognizes whether or not at least part of a frontward traveling vehicle, a lane-change target-position candidate frontward-traveling vehicle, and a lane-change target-position candidate rearward-traveling vehicle is present in the communication region CR according to information such as the position, the speed, and the like of the peripheral vehicle that is acquired by the communication unit  65 . In the example of  FIG. 26 , an inter-vehicle communication between the communication unit  65  and a peripheral vehicle m 2  that is traveling on the adjacent lane L 2  is established, and an inter-vehicle communication between the communication unit  65  and a peripheral vehicle m 3  that is traveling on the adjacent lane L 2  is established. Accordingly, the outside recognition unit  104  recognizes that the peripheral vehicle m 2  and the peripheral vehicle m 3  are present in the communication region CR. In the example of  FIG. 26 , the position of the peripheral vehicle m 2  is more frontward than the position of a lane change target position candidate T in the adjacent lane L 2 , and therefore, the outside recognition unit  104  recognizes the peripheral vehicle m 2  as the lane-change target-position candidate frontward-traveling vehicle. The position of the peripheral vehicle m 3  is more rearward than the position of the lane change target position candidate T in the adjacent lane L 2 , and therefore, the outside recognition unit  104  recognizes the peripheral vehicle m 3  as the lane-change target-position candidate rearward-traveling vehicle. On the other hand, information regarding other peripheral vehicles that travel on the travel lane L 1  is not acquired by the communication unit  65  (communication unestablished), the outside recognition unit  104  does not recognize the frontward traveling vehicle. 
     The determination part  112  determines whether or not a frontward traveling vehicle, a lane-change target-position candidate frontward-traveling vehicle, and a lane-change target-position candidate rearward-traveling vehicle are recognized by the outside recognition unit  104 . 
     In the example of  FIG. 26 , the virtual vehicle setting part  113  sets a virtual vehicle which virtually simulates a frontward traveling vehicle that is not recognized by the outside recognition unit  104 , in the vicinity of an outer edge of the communication region CR. The virtual vehicle setting part  113  sets the virtual vehicle vm as a movable body or a stationary body, similarly to the first to third embodiments described above. Thereby, it is possible for the another vehicle position change estimation part  114  to estimate a future position change, for example, with respect to any one or both of the recognized peripheral vehicle and the virtual vehicle that is set in the vicinity of the outer edge of the communication region CR. 
     According to the vehicle control apparatus  100 , the vehicle control method, and the vehicle control program in the fourth embodiment described above, a virtual vehicle is set according to a communication region while an inter-vehicle communication, and thereby, it is possible to perform further flexible automated driving, similarly to the first and third embodiments. 
     Although embodiments of the invention have been described with reference to the drawings, the present invention is not limited to the embodiments, and a variety of changes and substitutions can be added without departing from the scope of the invention. 
     DESCRIPTION OF THE REFERENCE SYMBOLS 
     
         
           20 : FINDER 
           30 : RADAR 
           40 : CAMERA 
           50 : NAVIGATION DEVICE 
           60 : VEHICLE SENSOR 
           65 : COMMUNICATION UNIT 
           72 : DRIVE FORCE OUTPUT DEVICE 
           74 : STEERING DEVICE 
           76 : BRAKE DEVICE 
           78 : OPERATION DEVICE 
           80 : OPERATION DETECTION SENSOR 
           82 : SWITCH 
           100 : VEHICLE CONTROL APPARATUS 
           102 : VEHICLE POSITION RECOGNITION UNIT 
           104 : OUTSIDE RECOGNITION UNIT 
           106 : ACTION PLAN GENERATION UNIT 
           110 : LANE CHANGE CONTROL UNIT 
           111 : TARGET POSITION CANDIDATE SETTING PART 
           112 : DETERMINATION PART 
           113 : VIRTUAL VEHICLE SETTING PART 
           114 : ANOTHER VEHICLE POSITION CHANGE ESTIMATION PART 
           115 : TRAVEL TRAJECTORY GENERATION PART 
           116 : TARGET POSITION DETERMINATION PART 
           120 : TRAVEL CONTROL PART 
           122 : CONTROL SWITCH UNIT 
           130 : STORAGE UNIT 
         M: VEHICLE