Patent Publication Number: US-2020298414-A1

Title: Robot and control method of robot

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a robot that mutually communicates with a user by interacting with the user and a control method of the robot. 
     2. Description of the Related Art 
     Techniques have been suggested in related art which decide behavior to be made by a robot in a case where the robot encounters a human. 
     For example, Japanese Patent No. 5409924 discloses a technique in which affinity of a human for a robot is calculated and an avoidance action of the robot and an expected avoidance action expected from the human are planned based on the affinity. Specifically, Japanese Patent No. 5409924 discloses that because the affinity of an elderly person for a robot tends to be low, the robot makes large avoidance not to cause the elderly person to have anxiety or discomfort (for example, paragraph [0015]). 
     Japanese Unexamined Patent Application Publication No. 2014-2514 discloses a technique in which in order to reduce a risk that a walking person loses walking balance or falls when the walking person reacts to a robot, avoidance behavior of the robot for the walking person is decided in accordance with motions of the legs of the walking person such that the walking person easily changes the direction (for example, paragraph [0016]). 
     SUMMARY 
     However, the above techniques in related art do not take into consideration an increase in opportunities of communication between a robot and a user at all, and further improvements have thus been demanded. 
     One non-limiting and exemplary embodiment provides a robot and a control method of a robot that may avoid an obstacle while increasing opportunities of communication between the robot and a user as much as possible. 
     In one general aspect, the techniques disclosed here feature a robot that mutually communicates with a user by interacting with the user. The robot includes a first sensor that detects an obstacle, a memory, and a processor. The memory stores a plurality of behavior types, each of the plurality of behavior types being a program for causing the robot to execute predetermined behavior, and the memory further stores a behavior type, which is executed by the robot, among the plurality of behavior types. The processor determines, by referring to the memory, which of the plurality of behavior types the behavior type executed by the robot when the first sensor detects the obstacle is; determines a type of the obstacle detected by the first sensor; decides whether first behavior for increasing opportunities of interaction with the user or second behavior for handling the obstacle is performed, based on the behavior type executed by the robot when the first sensor detects the obstacle and the type of the obstacle detected by the first sensor; and controls the robot to cause the robot to execute the decided behavior. 
     In the present disclosure, an obstacle may be avoided while opportunities of communication between a robot and a user are increased as much as possible. 
     It should be noted that general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any selective combination thereof. 
     Additional benefits and advantages of the disclosed embodiments will become apparent from the specification and drawings. The benefits and/or advantages may be individually obtained by the various embodiments and features of the specification and drawings, which need not all be provided in order to obtain one or more of such benefits and/or advantages. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an external appearance perspective view of a robot according to an embodiment of the present disclosure; 
         FIG. 2  is an internal perspective view of the robot according to the embodiment of the present disclosure; 
         FIG. 3  is a block diagram that illustrates the robot according to the embodiment of the present disclosure and a charger used for charging the robot; 
         FIG. 4  is a diagram that illustrates one example of a data configuration of a contact information database; 
         FIG. 5  is a flowchart that illustrates an obstacle handling process in the robot according to the embodiment of the present disclosure; and 
         FIG. 6  is a diagram that summarizes the obstacle handling process. 
     
    
    
     DETAILED DESCRIPTION 
     Underlying Knowledge Forming Basis of One Aspect of the Present Disclosure 
     First, a description will be made about a viewpoint leading a performance of one aspect according to the present disclosure. 
     The inventor studies a robot for an infant that sometimes educates a user, sometimes scolds the user, and sometimes becomes a playmate of the user through communication with the user. It is important for such a robot to increase as much as possible opportunities of communication between the robot and the user such as touching, talking, staring, being beside, and remotely operating, for example. Meanwhile, the robot has to make behavior for avoiding an obstacle when the obstacle is detected. 
     However, in a case where the detected obstacle is the user, if the robot is caused to avoid the obstacle similarly to a case where the obstacle is an object other than the user, friendliness of the user to the robot lowers, and an increase in opportunities of communication between the robot and the user may thereby be hindered. Consequently, in a case where an obstacle is detected, such a robot does not simply make avoidance behavior but has to make appropriate behavior in consideration of whether or not the obstacle is the user. 
     Japanese Patent No. 5409924 and Japanese Unexamined Patent Application Publication No. 2014-2514 relate to behavior control methods of robots. 
     In Japanese Patent No. 5409924, as described above, in a case where a robot encounters a human, the robot makes behavior for planning an avoidance action of the robot and an expected avoidance operation expected of the human based on the affinity of the human for the robot. 
     Further, in Japanese Unexamined Patent Application Publication No. 2014-2514, as described above, when a robot encounters a walking person, the robot makes behavior for avoiding the walking person in accordance with motions of the legs of the walking person such that the walking person easily changes the direction. 
     However, Japanese Patent No. 5409924 only discloses that the robot performs avoidance behavior in consideration of the affinity for a human. Further, Japanese Unexamined Patent Application Publication No. 2014-2514 only discloses that in a case where the obstacle is a walking person, the robot performs avoidance behavior in consideration of easiness of change of direction by the walking person. Thus, in both Japanese Patent No. 5409924 and Japanese Unexamined Patent Application Publication No. 2014-2514, increasing opportunities of communication between the robot and the user as much as possible is not taken into consideration at all. 
     Accordingly, the inventor has obtained a finding that behavior of a robot is decided in accordance with information of a behavior type of the robot itself in obstacle detection (for example, random travel, approach to a user, movement to a charger, movement in conversation, and so forth) and information of an obstacle type (for example, a user, an object, and so forth) and the robot may thereby be caused to avoid an obstacle while opportunities of mutual communication between the robot and the user are increased as much as possible and has conceived the following aspects according to the present disclosure. 
     One aspect of the present disclosure provides a robot that mutually communicates with a user by interacting with the user, the robot including:
         a first sensor that detects an obstacle;   a memory; and   a processor, in which   the memory stores a plurality of behavior types, each of the plurality of behavior types being a program for causing the robot to execute predetermined behavior,   the memory further stores a behavior type, which is executed by the robot, among the plurality of behavior types, and   the processor
           determines, by referring to the memory, which of the plurality of behavior types the behavior type executed by the robot when the first sensor detects the obstacle is,   determines a type of the obstacle detected by the first sensor,   decides whether first behavior for increasing opportunities of interaction with the user or second behavior for handling the obstacle is performed, based on the behavior type executed by the robot when the first sensor detects the obstacle and the type of the obstacle detected by the first sensor, and   controls the robot to cause the robot to execute the decided behavior.   
               

     In this configuration, whether the first behavior for increasing opportunities of interaction with the user or the second behavior for handling the obstacle is performed is decided based on the behavior type executed by the robot when the first sensor detects the obstacle and the type of the obstacle detected by the first sensor, and the decided behavior is executed by the robot. 
     Accordingly, switching may appropriately be made between the first behavior for increasing interaction with the user and the second behavior for handling the obstacle in accordance with whether the type of the obstacle is the user or an object, for example. As a result, in this configuration, an obstacle may be avoided while opportunities of communication between the robot and the user are increased as much as possible. 
     In the above aspect, in a case where the behavior type executed by the robot when the first sensor detects the obstacle is behavior in which the robot moves toward the user and the type of the obstacle detected by the first sensor is an object other than the user, the processor may decide that the first behavior that indicates a desire for removal of the obstacle is performed. 
     In this configuration, when an object other than the user is detected in execution of behavior in which the robot moves toward the user, behavior for avoiding the obstacle is not simply made, but the first behavior that indicates the desire for removal of the obstacle by the user is made. Accordingly, the robot may avoid the obstacle while increasing opportunities of communication with the user. 
     In the above aspect, in a case where the behavior type executed by the robot when the first sensor detects the obstacle is behavior in which the robot moves toward the user and the type of the obstacle detected by the first sensor is the user, the processor may decide that the first behavior that induces conversation with the user is performed. 
     In this configuration, when the user is detected in execution of behavior in which the robot moves toward the user, behavior for avoiding the user is not made, but the first behavior that induces conversation with the user is made. Accordingly, opportunities of communication between the robot and the user may be increased under a circumstance in which the user is present around the robot. 
     In the above aspect, in a case where the behavior type executed by the robot when the first sensor detects the obstacle is behavior in which the robot moves toward a charging stand and the type of the obstacle detected by the first sensor is an object other than the user, the processor may decide that the second behavior for avoiding the obstacle is performed. 
     In this configuration, in a case where an object other than the user is detected while the robot is moving to the charging stand due to a power shortage, for example, the second behavior for avoiding the object is made. Thus, the robot may avoid the object and quickly move to the charging stand in a case of a power shortage, and battery exhaustion of the robot may be prevented. 
     In the above aspect, in a case where the behavior type executed by the robot when the first sensor detects the obstacle is behavior in which the robot moves toward a charging stand and the type of the obstacle detected by the first sensor is the user, the processor may decide that the first behavior that indicates a desire for movement of the robot to the charging stand is performed. 
     In this configuration, in a case where the user is detected while the robot is moving to the charging stand due to a power shortage, for example, behavior for avoiding the user is not made, but the first behavior that indicates, to the user, the desire for movement of the robot to the charging stand is made. Accordingly, it becomes possible to induce the user to perform behavior for carrying the robot to the charging stand, and battery exhaustion of the robot may be prevented while opportunities of communication with the user are increased. 
     In the above aspect, in a case where the behavior type executed by the robot when the first sensor detects the obstacle is behavior in which the robot moves at random and the type of the obstacle detected by the first sensor is an object other than the user, the processor may decide that the second behavior for avoiding the obstacle is performed. 
     In this configuration, in a case where an object other than the user is detected as the obstacle in random travel, the second behavior for avoiding the object is made. Accordingly, for example, under a circumstance in which the possibility that the user is not present around the robot is high and the necessity for the robot and the user to have communication is low, a situation may be prevented in which the robot collides with an object other than the user and both or either one of those are damaged. 
     In the above aspect, in a case where the behavior type executed by the robot when the first sensor detects the obstacle is behavior in which the robot moves at random and the type of the obstacle detected by the first sensor is the user, the processor may decide that the first behavior that induces conversation with the user is performed. 
     In this configuration, in a case where the user is detected as the obstacle in the random travel, the first behavior that induces conversation with the user is made. Accordingly, under a circumstance in which the user is not very highly interested in the robot, for example, the robot makes an approach to the user for communication and enables the user to respond to this approach, and opportunities of communication between the robot and the user may thereby be increased. 
     In the above aspect, in a case where the behavior type executed by the robot when the first sensor detects the obstacle is behavior in which the robot has conversation with the user and the type of the obstacle detected by the first sensor is an object other than the user, the processor may decide that the first behavior that indicates a desire for removal of the obstacle is performed. 
     In this configuration, in a case where an object is detected as the obstacle in conversation with the user, behavior for avoiding the obstacle is not made, but the first behavior that indicates the desire for removal of the obstacle is made. Accordingly, the robot is capable of encouraging the user to make behavior for removing the obstacle and may avoid the obstacle while having communication with the user. 
     In the above aspect, in a case where the behavior type executed by the robot when the first sensor detects the obstacle is behavior in which the robot moves forward when the robot has conversation with the user and the type of the obstacle detected by the first sensor is the user, the processor may decide that the first behavior in which the robot is delighted to come close to the user is performed. 
     In this configuration, in a case where the user is detected as the obstacle when the robot makes behavior for moving forward in conversation with the user, the robot may be caused to make the first behavior in which the robot is delighted to approach to the user. Accordingly, the user may be caused to feel friendliness, and opportunities of communication between the robot and the user may be increased. 
     In the above aspect, in a case where the behavior type executed by the robot when the first sensor detects the obstacle is behavior in which the robot moves at random, the type of the obstacle detected by the first sensor is the user, and the user is an adult, the processor may decide that the first behavior that indicates a desire for movement away from the robot is performed. 
     In this configuration, in a case where an adult user is detected as the obstacle in the random travel, the first behavior that indicates, to the user, the desire for movement away from the robot is made. Accordingly, the user may be avoided while communication with an adult is made. 
     In the above aspect, the robot may further include a camera that acquires information of surroundings of the robot, a microphone that acquires a sound of surroundings of the robot, and a second sensor that detects that the robot is touched by a human. In a case where the behavior type executed by the robot when the first sensor detects the obstacle is behavior in which the robot moves toward the user or behavior in which the robot moves at random, the type of the obstacle detected by the first sensor is the user, and a contact amount with the user that is calculated based on any of the information acquired by the camera, the sound acquired by the microphone, and a detection result by the second sensor is equal to or greater than a threshold value, the processor may decide that the second behavior in which the robot avoids the user is performed. 
     In this configuration, in a case where the user is detected as the obstacle in movement toward the user or in random travel and the contact amount between the user and the robot that is obtained from the information acquired by the camera, the sound acquired by the microphone, and the detection result by the second sensor that detects that the robot is touched by a human is equal to or greater than the threshold value, behavior for avoiding the user is made. Accordingly, for example, a demand of a guardian of the user who does not desire that the robot has more communication with the user because the contact amount between the user and the robot is the threshold value or greater may be met. Here, the contact amount is an amount that indicates the quantity of interaction between the user and the robot and is contact time, a contact frequency, or the like, for example. Contact includes not only physical contact such as touching and stroking but also indirect contact such as having a dialog and being beside. 
     In the above aspect, the first behavior that indicates the desire for movement away from the robot may include performing a gesture that indicates the desire for movement away from the robot. 
     In this configuration, because the gesture that indicates the desire for movement away from the robot is employed as the first behavior, the desire may be implied to the user. 
     In the above aspect, the robot may further include a speaker that outputs a sound, and a display that displays information. The first behavior that indicates the desire for movement away from the robot may include at least one of (i) outputting a sound that indicates the desire for movement away from the robot and (ii) outputting video that indicates the desire for movement away from the robot. 
     In this configuration, because the desire for movement away from the robot may be notified to the user by using either one of the sound and the video, the desire may accurately be notified to the user. 
     In the above aspect, the robot may further include a speaker that outputs a sound, and a display that displays information. The first behavior that indicates the desire for removal of the obstacle may include performing a gesture that indicates the desire for removal of the obstacle. 
     In this configuration, because the gesture that indicates the desire for removal of the obstacle is employed as the first behavior, the desire may be implied to the user. 
     In the above aspect, the robot may further include a speaker that outputs a sound, and a display that displays information. The first behavior that indicates the desire for removal of the obstacle may include at least one of (i) outputting a sound that indicates the desire for removal of the obstacle from the speaker and (ii) displaying information that indicates the desire for removal of the obstacle on the display. 
     In this configuration, because the desire for removal of the obstacle may be notified to the user by using either one of the sound and the video, the desire may accurately be notified to the user. 
     In the above aspect, the first behavior that induces conversation with the user may include at least one of (i) causing the robot to make contact with the user and (ii) swinging the robot in a left-right direction. 
     In this configuration, because behavior in which the robot makes contact with the user or the robot performs an action of swaying in the left-right direction is employed as the first behavior that induces conversation with the user, conversation with the user may be induced by causing the robot to make an action like asking for something. 
     In the above aspect, the robot may further include a speaker that outputs a sound, a display that displays information, and a microphone that acquires a sound of surroundings of the robot. The first behavior that induces conversation with the user may include at least one of (i) outputting a sound that induces conversation with the user from the speaker, (ii) directing the display toward the user, and (iii) directing the microphone toward the user. 
     In this configuration, indication of intention of conversation may accurately be notified to the user through at least one of the sound and the video, and utterance from the user may accurately be acquired by directing the microphone to the user. 
     In the above aspect, the first behavior that indicates the desire for movement of the robot to the charging stand may include performing a gesture that indicates the desire for movement of the robot to the charging stand. 
     In this configuration, because the gesture that indicates the desire for movement to the charging stand is employed as the first behavior, the desire may be implied to the user. 
     In the above aspect, the robot may further include a speaker that outputs a sound, and a display that displays information. The first behavior that indicates the desire for movement of the robot to the charging stand may include at least one of (i) outputting a sound that indicates the desire for movement of the robot to the charging stand from the speaker and (ii) displaying information that indicates the desire for movement of the robot to the charging stand on the display. 
     In this configuration, because the desire for movement to the charging stand may be notified to the user by using either one of the sound and the video, the desire may accurately be notified to the user. 
     In the above aspect, the first behavior in which the robot is delighted to come close to the user may include performing a gesture that indicates that the robot is delighted to come close to the user. 
     In this configuration, through the gesture of delight of coming close to the user, the delight is notified to the user, and the delight may thus be implied to the user. 
     In the above aspect, the robot may further include a speaker that outputs a sound, and a display that displays information. The first behavior in which the robot is delighted to come close to the user may include at least one of (i) outputting a sound that indicates that the robot is delighted to come close to the user from the speaker and (ii) displaying information that indicates that the robot is delighted to come close to the user on the display. 
     In this configuration, because the delight of coming close to the user may be notified to the user by using either one of the sound and the video, the delight may accurately be notified to the user. 
     The present disclosure may also be realized as a program that causes a computer to execute each of characteristic configurations included in such a robot or as a control method of a robot that acts by the program. Further, it is matter of course that such a program may be distributed via a computer-readable and non-transitory recording medium such as a CD-ROM or a communication network such as the Internet. 
     EMBODIMENT 
     An embodiment of the present disclosure will hereinafter be described with reference to drawings. The embodiment described in the following illustrates one specific example of the present disclosure. Values, shapes, configuration elements, steps, orders of steps, and so forth that are described in the following embodiment are examples and are not intended to limit the present disclosure. Further, the configuration elements that are not described in the independent claims which provide the most superordinate concepts among the configuration elements in the following embodiment will be described as arbitrary configuration elements. 
     First, details of an external appearance of a robot according to the embodiment of the present disclosure will be described with reference to  FIG. 1  and  FIG. 2 .  FIG. 1  is an external appearance perspective view of the robot according to the embodiment of the present disclosure, and  FIG. 2  is an internal perspective view of the robot according to the embodiment of the present disclosure. 
     As illustrated in  FIG. 1 , a robot  1  includes a spherical main housing  121 , a first spherical cap portion  122 , and a second spherical cap portion  123 . The main housing  121 , the first spherical cap portion  122 , and the second spherical cap portion  123  configure a sphere as the whole. That is, the robot  1  has a spherical shape. The robot  1  makes contact with a user while two-dimensionally moving in a predetermined space. The first spherical cap portion  122  and the second spherical cap portion  123  are coupled together by a shaft (not illustrated) provided to the main housing  121 . By contrast, the shaft is not fixed to the main housing  121 . Consequently, the robot  1  moves forward or rearward by rotating the main housing  121  about the shaft. 
     Further, as illustrated in  FIG. 1 , the robot  1  includes a camera  101  and a microphone  103  in the first spherical cap portion  122 . In addition, a speaker  113  is provided in an internal portion of the main housing  121 . The speaker  113  outputs sounds of the robot  1 . The camera  101  acquires video of a surrounding environment of the robot  1 . The microphone  103  acquires sounds of the surrounding environment of the robot  1 . Note that the speaker  113  may be provided to either of the first spherical cap portion  122  and the second spherical cap portion  123 . In this embodiment, the robot  1  includes the camera  101  in the first spherical cap portion  122 , but this embodiment is not limited to this. The camera  101  may be included in at least one of the first spherical cap portion  122  and the second spherical cap portion  123 , the arrangement place and the number of cameras  101  are adjusted, and it thereby becomes possible to acquire video of  360  degrees around the robot  1 . In this embodiment, the robot  1  includes the microphone  103  in the first spherical cap portion  122 , but this embodiment is not limited to this. The microphone  103  may be included in at least one of the first spherical cap portion  122  and the second spherical cap portion  123 . 
     As illustrated in  FIG. 2 , the robot  1  includes a first display  111   a,  a second display  111   b,  and a third display  111   c  in an internal portion of the main housing  121 . The first display  111   a,  the second display  111   b,  and the third display  111   c  are installed in a fixing metal plate  125 . The fixing metal plate  125  is mounted on the shaft via an arm  126 . The first display  111   a,  the second display  111   b,  and the third display  111   c  are configured with plural light emitting diodes, for example. The first display  111   a,  the second display  111   b,  and the third display  111   c  display a facial expression of the robot  1 . Specifically, the first display  111   a,  the second display  111   b,  and the third display  111   c  individually control lighting of the plural light emitting diodes and thereby display part of a face of the robot  1  as illustrated in  FIG. 1 , for example, eyes and a mouth. In the examples of  FIG. 1  and  FIG. 2 , the first display  111   a  displays an image of the right eye, the second display  111   b  displays an image of the left eye, and the third display  111   c  displays an image of the mouth. Further, the images of the right eye, the left eye, and the mouth pass through the main housing  121  formed of a transparent or translucent member and are projected to the outside. 
     As illustrated in  FIG. 2 , the robot  1  includes a weight  127  in a lower portion of the internal portion of the main housing  121 . Thus, the center of gravity of the robot  1  is positioned at a lower portion of the center of the main housing  121 . Accordingly, the action of the robot  1  may be stabilized. 
     Next, details of an internal circuit of the robot  1  according to the embodiment of the present disclosure will be described with reference to  FIG. 3 .  FIG. 3  is a block diagram that illustrates the robot  1  according to the embodiment of the present disclosure and a charger  2  used for charging the robot  1 . 
     As illustrated in  FIG. 3 , the robot  1  includes the camera  101 , the microphone  103 , a sensor  105 , a power supply  109 , a display  111 , the speaker  113 , a driving mechanism  115 , a processor  100 , and a memory  130 . The processor  100  includes a video processor  102 , a sound processor  104 , a sensor information processor  106 , a main controller  107 , a management unit  108 , a power supply controller  110 , a display controller  112 , a sound controller  114 , and a driving mechanism controller  116 . Further, the charger  2  includes a charge controller  117 . The processor  100  is an electric circuit such as a CPU, for example, and the memory  130  is a non-volatile semiconductor memory, for example. 
     The camera  101  acquires video of the surrounding environment of the robot  1 . The microphone  103  acquires sounds of the surrounding environment of the robot  1 . The sensor  105  is configured with a distance sensor, a thermal image sensor, an illuminance sensor, a gyro sensor, an acceleration sensor, a geomagnetic sensor, a pressure-sensitive sensor, a proximity sensor, a fingerprint authentication sensor, a vein authentication sensor, and so forth, for example. Information acquired by the sensor  105  includes information that indicates the surrounding environment of the robot  1 , user operation information for the robot  1 , and so forth. The information that indicates the surrounding environment is obtained from the distance sensor, the thermal image sensor, the illuminance sensor, and so forth, for example. The operation information is obtained from the gyro sensor, the acceleration sensor, the geomagnetic sensor, the pressure-sensitive sensor, the proximity sensor, the fingerprint authentication sensor, the vein authentication sensor, and so forth, for example. Note that the distance sensor, the thermal image sensor, and the fingerprint authentication sensor that configure the sensor  105 , the camera  101 , and the microphone  103  are examples of a first sensor for detecting an obstacle. Further, the gyro sensor, the acceleration sensor, the geomagnetic sensor, the pressure-sensitive sensor, the proximity sensor, the fingerprint authentication sensor, and the vein authentication sensor that configure the sensor  105  are examples of a second sensor that detects that the robot is touched by a human. 
     The video processor  102  analyzes a type of an obstacle (for example, a user, an object, and so forth), a position of the obstacle, a size of the obstacle, a kind of a facial expression in a case where the obstacle is the user, and attribute information (for example, a user ID, an age, and so forth) from the video acquired by the camera  101 , stores analysis results as video analysis results in the memory  130 , and thereby manages the video analysis results. Kinds of facial expressions include positive expressions such as “smiling face” and “surprised face” and negative expressions such as “sad face” and “worried face”, for example. 
     The sound processor  104  analyzes presence or absence of a sound of the user, a kind of a sound, and attribute information (for example, a user ID, an age, and so forth) from the sound acquired by the microphone  103 , stores analysis results as sound analysis results in the memory  130 , and thereby manages the sound analysis results. Kinds of sounds include positive expression such as “I like you” and “play more” and negative expressions such as “I hate you” and “go away”, for example. 
     The sensor information processor  106  analyzes a type of an obstacle (for example, a user, an object, and so forth), a position of the obstacle, a size of the obstacle, the distance from the robot  1  to the obstacle, and so forth from the information that is obtained by the sensor  105  and indicates the surrounding environment. Further, the sensor information processor  106  analyzes an operation time, an operation frequency, and a kind of an operation by the user, for example, from the operation information acquired by the sensor  105 . Then, the sensor information processor  106  stores those analysis results as sensor analysis results in the memory  130  and thereby manages the sensor analysis results. Kinds of operations include positive expressions such as “touching” and “stroking” and negative expressions such as “hitting” and “flicking”, for example. The kind of an operation is identified based on a waveform pattern of the pressure-sensitive sensor that configures the sensor  105 , for example. 
     For example, an obstacle is detected from the information obtained by the sensor information processor  106 , the video that includes the obstacle is analyzed by the video processor  102 , and the type of the obstacle, that is, whether the obstacle is an object or the user, is thereby analyzed. Further, in a case where the type of an obstacle is the user, the video that includes the user is analyzed (for example, face authentication, a facial expression detection process, and so forth) by the video processor  102 , and the facial expression of the user, the attribute information of the user, and so forth are thereby analyzed. 
     However, this is one example, and the attribute information of the user may be acquired by voiceprint authentication, which is performed by the sound processor  104 , of the sound acquired by the microphone  103 , for example, or the attribute information of the user may be acquired by an analysis, which is performed by the sensor information processor  106 , of the information acquired by the fingerprint authentication sensor or the vein authentication sensor that configures the sensor  105 . Further, distinction of whether the obstacle is an object or the user may be performed by an analysis, which is performed by the sensor information processor  106 , of the temperature distribution of the obstacle that is indicated by the information acquired by the thermal image sensor which configures the sensor  105 , for example. 
     Further, the robot  1  is charged by the charger  2 . The power supply  109  is a secondary battery such as a lithium-ion battery that is charged by the charger  2 , for example, and is an electric power supply of the robot  1 . The power supply controller  110  manages the power stored in the power supply  109  by control by the charge controller  117  of the charger  2 . 
     Specifically, the power supply controller  110  stores a charging flag that represents whether the power state of the robot  1  is on charge and information of the remaining power amount of the power supply  109  in the memory  130  and thereby manages the power supply  109 . In addition, the power supply controller  110  reads out the charging flag and the information of the remaining power amount from the memory  130  and outputs those to the main controller  107 . In addition, the power supply controller  110  controls the charge to the power supply  109  together with the charge controller  117  of the charger  2  in a case where the robot  1  is connected with the charger  2 . 
     The management unit  108  stores behavior type information  132  that indicates a present behavior type of the robot  1  in the memory  130  and thereby manages the behavior type of the robot  1 . In this embodiment, for example, the behavior types are categorized into four types of random travel, approach to the user, movement to the charger, and movement in conversation. However, the present disclosure is not limited to this, but the behavior types may be categorized into three types or five types or more. Further, the behavior types are not limited to the above-described four types, but other behavior types may be employed. 
     Here, random travel is travel of the robot  1  in which the robot  1  moves forward or rearward at random, turns left or right, and changes a traveling speed, for example. The random travel is the behavior type executed under a circumstance in which a task is not given to the robot  1 , for example, and is a basic state of the robot  1 . Accordingly, the robot  1  autonomously behaves even under a circumstance in which a task is not given and may thereby acts as if the robot  1  were a pet. Note that a task is work assigned to the robot  1  in order to achieve a certain purpose, for example, conversation with the user, approach to the user, movement to a charging stand, and so forth. 
     Approach to the user is approach to the side of the user in a case where the robot  1  finds the user, for example. The approach to the user is executed in a case where the robot  1  detects the user in the random travel, for example. Movement to the charger  2  is executed in a case where the remaining power amount of the power supply  109  becomes a predetermined value or less. In the movement to the charger  2 , the robot  1  searches for the charger  2  and moves to the charger  2  in order to charge the power supply  109 . Note that the movement to the charger  2  is executed in preference to the other behavior types in order to prevent battery exhaustion of the robot  1 , for example. 
     Movement in conversation is movement of the robot  1  in a case where the robot  1  has conversation with the user, for example. The robot  1  has conversation with the user by executing a dialog program or a play program that is in advance installed and is configured with predetermined facial expressions, sounds, and motions. Here, the dialog program includes self-introduction, greetings, a weather forecast, schedule confirmation, a chat, and so forth, which are targeted for children, for example. The play program includes word-chain game, quiz, rock paper scissors, reading of a picture book or the like, care play, singing, hide and seek, encouragement of living habits, and so forth, which are targeted for children, for example. 
     In addition, the management unit  108  accumulates contact information that is a history of contact between the robot  1  and the user in a contact information database (DB)  131  and manages the contact information.  FIG. 4  is a diagram that illustrates one example of a data configuration of the contact information database  131 . The contact information database  131  is a database in which one piece of contact information is allocated to one row and stores information about the user as a contacted party of the robot  1  and a contact content while associating those together. 
     Here, “contact” indicates a situation in which the user is beside the robot  1 , the user looks at the robot  1 , the user talks with the robot  1 , the user touches the robot  1 , or the user remotely operates the robot  1  by a remote controller operation, a gesture operation, a sound of clapping, or the like. That is, “contact” not only indicates physical contact between the user and the robot  1  but also includes indirect contact between the user and the robot  1  and indicates interaction between the user and the robot to have communication. 
     Specifically, the contact information DB  131  stores “contact date and time”, “contacted party”, and “contact content” while associating those together. “Contact date and time” indicates a start time and an end time in contact between the robot  1  and the user. The time from the start time to the end time stored in “contact date and time” becomes the contact time between the robot  1  and the user. 
     “Contacted party” indicates information about the user who makes contact with the robot  1  and includes columns of “user ID”, “kind of user”, and “facial expression of user”. “User ID” is an identifier of the user who makes contact with the robot  1 . “User ID” is in advance allotted to each of one or more users who live in a house in which the robot  1  is present, for example. The management unit  108  acquires the user ID indicated by the video analysis results by the video processor  102  via the main controller  107  and records the user ID in the column of “user ID”. 
     “Kind of user” is attribute information of the user who makes contact with the robot  1 . Here, as “kind of user”, for example, a child or an adult is employed. However, this is one example, and attribute information such as mother, father, eldest son, and eldest daughter may be employed, age may be employed, or male or female may be employed, for example. The management unit  108  acquires the kind of user included in the video analysis results by the video processor  102  via the main controller  107  and records the kind of user in the column of “kind of user”. 
     “Facial expression of user” indicates a kind of a facial expression of the user in contact between the robot  1  and the user. Here, “facial expression of user” includes positive expressions such as “smile” and “surprised face” and negative expressions such as “sad face”, “worried face”, and “angry face”, for example. The management unit  108  acquires the kind of a facial expression included in the video analysis results by the video processor  102  via the main controller  107  and records the kind of a facial expression in the column of “facial expression of user”. 
     “Contact content” indicates a content of contact between the user and the robot  1 . Here, “contact content” includes operations to the robot  1  by the user such as “hitting the robot”, “stroking the robot”, “rubbing the robot”, and “operating the robot by a remote controller”, utterance contents of the user to the robot  1  such as “I like you”, “play more”, “I hate you”, and “go away”, and so forth, for example. In addition, “contact content” includes behavior to the robot  1  by the user, for example, to have interaction such as “looking at the robot”, “being beside the robot”, and “clapping”. The management unit  108  acquires the kind of an operation included in the sensor analysis results by the sensor information processor  106 , the kind of a sound included in the sound analysis results by the sound processor  104 , and the kind of a facial expression included in the video analysis results by the video processor  102  via the main controller  107 , for example, and records those kinds in the column of the contact content. 
     In addition to those, the contact information database  131  may include columns such as contact time and contact frequency between the robot  1  and the user. The contact time may be obtained as the difference between the recorded start time and the recorded end time in the column of “contact date and time”. The contact frequency is a frequency of operations to the robot  1  by the user in one piece of contact. For example, the contact frequency of “hitting the robot” is the frequency of hitting on the robot  1  by the user, and the contact frequency of “stroking the robot” is the frequency of stroking on the robot  1  by the user. 
     The display  111  is configured with the first display  111   a,  the second display  111   b,  and the third display  111   c,  which are illustrated in  FIG. 2 . The display  111  is configured with plural light emitting diodes that are aligned at predetermined intervals, for example, and outputs display information that indicates the facial expression of the robot  1 . Specifically, the display  111  individually controls lighting of the plural light emitting diodes and thereby displays part of the face of the robot  1 , for example, the eyes and the mouth. 
     The display controller  112  outputs a display signal for outputting the display information, which corresponds to a behavior control command output from the main controller  107 , from the display  111 . Accordingly, the display  111  outputs a facial expression of the robot  1 . 
     The sound controller  114  outputs a sound signal for outputting a sound, which corresponds to the behavior control command output from the main controller  107 , from the speaker  113 . Accordingly, the speaker  113  outputs a sound of the robot  1 . 
     The driving mechanism  115  is configured with plural motors, a frame, gears, a driving belt, the shaft, and so forth, for example, and causes the robot  1  to act. Specifically, the driving mechanism  115  controls the plural motors and thereby changes the direction of the face of the robot  1  or causes the robot  1  to move. 
     Referring to  FIG. 2 , for example, the plural motors include a first motor that rotates the main housing  121  and causes the robot  1  to travel, a second motor that rotates the weight  127  about the front-rear direction and inclines the posture of the robot  1  about the left-right direction, and a third motor that rotates the arm  126  about the shaft and inclines the eyes and the mouth of the robot  1  upward or downward. The frame is suspended from the shaft and houses the plural motors, gears, and the driving belt. The plural gears have the driving belt wound around those and transmit the rotational force of the third motor to the arm  126 . 
     Specifically, the driving mechanism  115  drives the first motor to the third motor in accordance with a driving signal from the driving mechanism controller  116 , thereby causes the robot  1  to travel, causes the robot  1  to make a turn, and inclines the eyes and the mouth of the robot  1  upward or downward. Note that the robot  1  makes a right turn by moving forward while inclining the weight  127  in the right direction when the front side is seen from the rear side and makes a left turn by moving forward while inclining the weight  127  in the left direction. 
     The driving mechanism controller  116  outputs a control signal for operating the driving mechanism  115  of the robot  1  in accordance with the behavior control command output from the main controller  107 . Accordingly, the driving mechanism  115  causes the robot  1  to perform the action that corresponds to the behavior control command. 
     The main controller  107  acquires the video analysis results from the video processor  102 . The main controller  107  acquires the sound analysis results of the user from the sound processor  104 . The main controller  107  acquires the sensor analysis results from the sensor information processor  106 . The main controller  107  acquires the behavior type information  132  from the management unit  108 . 
     The main controller  107  decides “contact date and time”, “contacted party”, and “contact content” from a recognition result of the user included in the video analysis results acquired from the video processor  102 , a sound recognition result of the user acquired from the sound processor  104 , and an operation recognition result of the user acquired from the sensor information processor  106 , generates the contact information, and outputs the contact information to the management unit  108 . In addition, the main controller  107  acquires the contact information of the user as the contacted party from the management unit  108  in an obstacle handling process that will be described later. 
     The main controller  107  acquires the charging flag of the power state of the power supply  109  and information of the remaining power amount from the power supply controller  110 . 
     The main controller  107  generates the behavior control command based on the video analysis results from the video processor  102 , the sensor analysis results from the sensor information processor  106 , and information acquired from the management unit  108  and outputs the behavior control command to the display controller  112 , the sound controller  114 , and the driving mechanism controller  116 . Details of contents of the behavior control command will be described later. 
     The main controller  107  periodically acquires the charging flag from the power supply controller  110  and performs the obstacle handling process, which will be described with reference to  FIG. 5 , in a case where the charging flag is OFF, that is, in a case where the power state of the robot  1  is not on charge. Note that the condition for performing the obstacle handling process is not limited to this. For example, the main controller  107  may further periodically acquire information of the remaining power amount of the power supply  109  from the power supply controller  110  in addition to the charging flag and may perform the obstacle handling process, which will next be described, in a case where the charging flag is OFF and the remaining power amount indicated by the information of the remaining power amount is a predetermined value or greater. 
     Next, the obstacle handling process in the robot  1  according to the embodiment of the present disclosure will be described with reference to  FIG. 5 .  FIG. 5  is a flowchart that illustrates the obstacle handling process in the robot  1  according to the embodiment of the present disclosure. 
     First, the main controller  107  acquires the sensor analysis results from the sensor information processor  106  and determines whether or not an obstacle is detected by the sensor  105  in a predetermined distance from the robot  1  (S 201 ). The predetermined distance is a distance determined in advance in which the robot  1  is capable of interacting with the user. 
     In a case where an obstacle is not detected by the sensor  105  in the predetermined distance from the robot  1  (a case of “No” in S 201 ), the main controller  107  terminates the obstacle handling process. 
     On the other hand, in a case where an obstacle is detected by the sensor  105  in the predetermined distance from the robot  1  (a case of “Yes” in S 201 ), the main controller  107  outputs the behavior control command for stopping travel of the robot  1  to the driving mechanism controller  116  (S 202 ). In this case, in addition to this behavior control command, the main controller  107  may output, to the display controller  112  and the sound controller  114 , the behavior control command for lighting the plural light emitting diodes of the display  111  that are positioned at the coordinates for reproducing a predetermined facial expression (for example, a surprised face, a sad face, and so forth) and the behavior control command for causing the robot  1  to utter a predetermined sound (for example, “oops”, “that was close”, “something might be there”, and so forth), respectively. 
     Next, the main controller  107  acquires, from the management unit  108 , the behavior type information  132  (for example, random travel, approach to the user, movement to the charger, movement in conversation, and so forth) of the robot  1  immediately before stop of travel of the robot  1  in step S 202  (S 203 ). 
     Next, the main controller  107  determines whether or not the type of the obstacle detected in step S 201  is the user from the types of obstacles (for example, the user, an object, and so forth) included in the video analysis results about the video acquired by the camera  101 , the types of obstacles being acquired from the video processor  102  (S 204 ). 
     In this flow, in S 204 , the main controller  107  only distinguishes whether the obstacle is a person or an object and does not have to specify the attribute information of the user such as the user ID. However, this is one example. In a case where a mode is employed which will be described later and in which the contact information DB  131  is referred to, the main controller  107  specifies the attribute information of the user in S 204 . 
     Further, in this flow, as indicated in step S 201  and step S 204 , detection of an obstacle and detection of the user are separately conducted. However, this is one example, and detection of an obstacle and the detection of the user may simultaneously be conducted in step S 201 . 
     For example, in step S 201 , in a case where an obstacle is detected by the sensor  105 , the main controller  107  may cause the video processor  102  to analyze the video of the camera  101 , acquire the video analysis results from the video processor  102 , and thereby determine whether or not the obstacle detected by the sensor  105  is the user. 
     Alternatively, in step S 201 , it is assumed that when the obstacle is detected by the sensor  105 , the user as the obstacle utters. In this case, the main controller  107  may recognize the user from the attribute information included in the sound analysis results. 
     In a case where the determination result in step S 204  indicates that the obstacle is the user (a case of “Yes” in S 204 ), the main controller  107  determines whether or not the present behavior type of the robot  1  is “random travel” from the behavior type information  132  acquired in step S 203  (S 205 ). 
     In a case where the determination result in step S 205  is “random travel” (a case of “Yes” in S 205 ), the main controller  107  outputs the behavior control command, by which the robot  1  conducts “conversation inducing utterance” for the user, to the display controller  112  and the sound controller  114  (S 206 ) and terminates the obstacle handling process. 
     A specific example of “conversation inducing utterance” in “random travel” is as follows. The main controller  107  outputs, to the display controller  112 , the behavior control command for lighting the plural light emitting diodes of the display  111 , which are positioned at the coordinates which enable reproduction of a facial expression of asking a favor (for example, both eyes in the shape of “{circumflex over ( )} {circumflex over ( )}” or the like) as illustrated in the first row and first column of table H 6  in  FIG. 6 . Further, the main controller  107  outputs, to the sound controller  114 , the behavior control command that causes the robot  1  to utter a sound with a content by which the robot  1  induces the user to become a partner of conversation such as “play with me”, for example, as illustrated in the first row and first column of table H 6  in  FIG. 6 . Then, when output of all the behavior control commands is completed, the main controller  107  terminates the obstacle handling process. 
     In such a manner, in this embodiment, in a case where the obstacle detected by the robot  1  is the user in “random travel”, the robot  1  does not avoid the obstacle, that is, the user but performs “conversation inducing utterance” that encourages the user to have conversation. Accordingly, opportunities of communication between the robot  1  and the user may be increased as much as possible. 
     Note that the facial expressions and the sounds of the robot  1 , which are described here, are examples, and the facial expressions and the sounds are not limited to those. For example, the main controller  107  may output only the behavior control command that causes the robot  1  to utter a sound to the sound controller  114 . In this case, communication between the robot  1  and the user may be made only by the sound output from the speaker  113 . Further, the main controller  107  may output only the behavior control command for displaying text information, in which the sound uttered by the robot  1  is displayed as text, as a facial expression to the display controller  112 . In this case, communication between the robot  1  and the user may be made only by the text information displayed on the display  111 . Further, the main controller  107  may output the behavior control command for outputting both a sound uttered by the robot  1  and the text information of the sound to the display controller  112  and the sound controller  114 . In this case, communication between the robot  1  and the user may be made by using the sound and the text information. 
     Furthermore, in addition to the sound and the facial expression of the robot  1 , the main controller  107  may output, to the driving mechanism controller  116 , the behavior control command that causes the robot  1  to make a predetermined motion (for example, sway in the left-right direction, a nod in the up-down direction, and so forth). In this case, the robot  1  may more effectively induce the user to become a partner of conversation by using a motion as well. Further, the main controller  107  may output not only the behavior control command for inducing the user to become a partner of conversation but also the following behavior control commands. That is, the main controller  107  may output the behavior control commands for inducing communication without utterance, by which the robot  1  gently taps the user by a main body, the robot  1  directs the display  111  toward the user and thereby makes a facial expression of looking at the user, the robot  1  sways beside the user, the robot  1  directs the microphone  103  (ear portion) of the robot  1  in the direction toward the user, and so forth, for example. 
     On the other hand, in a case where the determination result in step S 205  is not “random travel” (a case of “No” in S 205 ), the main controller  107  determines whether or not the present behavior type of the robot  1  is “approach to the user” from the behavior type information  132  acquired in step S 203  (S 207 ). 
     In a case where the determination result in step S 207  is “approach to the user” (a case of “Yes” in S 207 ), the process moves to above-described step S 206 , “conversation inducing utterance” is performed, and the obstacle handling process is thereafter terminated. 
     On the other hand, in a case where the determination result in step S 207  is not “approach to the user” (a case of “No” in S 207 ), the main controller  107  determines whether or not the present behavior type of the robot  1  is “movement to the charger” from the behavior type information  132  of the robot  1  acquired in step S 203  (S 208 ). 
     In a case where the determination result in step S 208  is “movement to the charger” (a case of “Yes” in S 208 ), the main controller  107  outputs the behavior control command, by which the robot  1  conducts “charging inducing utterance” for the user, to the display controller  112  and the sound controller  114  (S 209 ) and terminates the obstacle handling process. 
     A specific example of the charging inducing utterance is as follows. The main controller  107  outputs, to the display controller  112 , the behavior control command for lighting the plural light emitting diodes of the display  111 , which are positioned at the coordinates which enable reproduction of a facial expression of asking for help (for example, both eyes in the shape of “&gt;&lt;” or the like) as illustrated in the third row and first column of table H 6  in  FIG. 6 . Further, the main controller  107  outputs, to the sound controller  114 , the behavior control command that causes the robot  1  to utter a sound with a content by which the robot  1  induces the user to carry and return the robot  1  to the charger  2  such as “return me to the charger”, for example, as illustrated in the third row and first column of table H 6  in  FIG. 6 . Then, when output of all the behavior control commands is completed, the main controller  107  terminates the obstacle handling process. 
     In such a manner, in this embodiment, in a case where the obstacle detected by the robot  1  is the user in “movement to the charger”, the robot  1  does not avoid the obstacle, that is, the user but encourages the user to carry the robot  1  to the charger  2 . Accordingly, opportunities of communication between the robot  1  and the user may be increased as much as possible. 
     Note that the facial expressions and the sounds of the robot  1 , which are described here, are examples, and the facial expressions and the sounds are not limited to those. For example, the main controller  107  may output only the behavior control command that causes the robot  1  to utter a sound to the sound controller  114 . In this case, communication between the robot  1  and the user may be made only by the sound output from the speaker  113 . Further, the main controller  107  may output only the behavior control command for displaying text information, in which the sound uttered by the robot  1  is displayed as text, as a facial expression to the display controller  112 . In this case, communication between the robot  1  and the user may be made only by the text information displayed on the display  111 . Further, the main controller  107  may output the behavior control command for outputting both a sound uttered by the robot  1  and the text information of the sound to the sound controller  114  and the display controller  112 . In this case, communication between the robot  1  and the user may be made by using the sound and the text information. 
     Furthermore, in addition to the sound and the facial expression of the robot  1 , the main controller  107  may output, to the driving mechanism controller  116 , the behavior control command that causes the robot  1  to make a predetermined motion (for example, sway in the left-right direction, a nod in the up-down direction, and so forth) and may thereby cause the robot  1  to perform a gesture that indicates that the robot  1  desires to be moved to the charger  2 . In this case, the robot  1  may more effectively induce the user to carry the robot  1  to the charger  2  by using a motion as well. 
     On the other hand, in a case where the determination result in step S 208  is not “movement to the charger” (a case of “No” in S 208 ), that is, does not correspond to any of “random travel”, “approach to the user”, and “movement to the charger” but is “movement in conversation”, the main controller  107  outputs the behavior control command, by which the robot  1  conducts reaction utterance for the user, to the display controller  112  and the sound controller  114  (S 210 ) and terminates the obstacle handling process. The movement in conversation includes forward movement of the robot  1 . 
     A specific example of the reaction utterance is as follows. The main controller  107  outputs, to the display controller  112 , a command for lighting the plural light emitting diodes of the display  111 , which are positioned at the coordinates which enable reproduction of a delighted facial expression (for example, both eyes in the shape of “{circumflex over ( )} {circumflex over ( )}” or the like) as illustrated in the fourth row and first column of table H 6  in  FIG. 6 , as the behavior control command. Further, the main controller  107  outputs, to the sound controller  114 , the behavior control command that causes the robot  1  to utter a sound as a reaction to the user such as “I am happy being beside you”, for example, as illustrated in the fourth row and first column of table H 6  in  FIG. 6 . Then, when output of all the behavior control commands is completed, the main controller  107  terminates the obstacle handling process. 
     In such a manner, in this embodiment, in a case where the obstacle detected by the robot  1  is the user in “movement in conversation”, the robot  1  does not avoid the obstacle, that is, the user but performs “reaction utterance” to the user. Thus, opportunities of communication between the robot  1  and the user may be increased as much as possible. 
     Note that the facial expressions and the sounds of the robot  1 , which are described here, are examples, and the facial expressions and the sounds are not limited to those. For example, the main controller  107  may output only the behavior control command that causes the robot  1  to utter a sound to the sound controller  114 . In this case, communication between the robot  1  and the user may be made only by the sound output from the speaker  113 . Further, only the behavior control command for displaying text information, in which the sound uttered by the robot  1  is displayed as text, as a facial expression may be output to the display controller  112 . In this case, communication between the robot  1  and the user may be made only by the text information displayed on the display  111 . Further, the main controller  107  may output the behavior control command for outputting both a sound uttered by the robot and the text information of the sound to the display controller  112  and the sound controller  114 . In this case, communication between the robot  1  and the user may be made by using the sound and the text information. 
     Furthermore, in addition to the sound and the facial expression of the robot  1 , the main controller  107  may output, to the driving mechanism controller  116 , the behavior control command that causes the robot  1  to make a predetermined motion (for example, sway in the left-right direction, a nod in the up-down direction, and so forth) and may thereby cause the robot  1  to perform a gesture of being delighted to come close to the user. In this case, the robot  1  may more effectively perform the reaction to the user by using a motion as well. 
     On the other hand, in a case where the determination result in step S 204  indicates that the obstacle is not the user (a case of “No” in S 204 ), that is, a case where the obstacle is an object, the main controller  107  determines whether or not the behavior type information  132  acquired in step S 203  is “random travel” (S 211 ). 
     In a case where the determination result in step S 211  is “random travel” (a case of “Yes” in S 211 ), the main controller  107  outputs the behavior control command, by which the robot  1  travels while avoiding the obstacle, to the driving mechanism controller  116  (S 212 ) and terminates the obstacle handling process. One example of an avoidance method of an obstacle is a method in which a stopping place of the robot  1  in step S 202  is set as an initial point and the robot  1  moves rearward for a predetermined distance, thereafter turns left or right, and moves forward, for example. Another example of the avoidance method of an obstacle is a method, in which the robot  1  makes a turn by a predetermined angle at a present place and thereafter moves forward, or the like. Still another example of the avoidance method of an obstacle is a method, in which the robot  1  turns right or left without moving rearward, or the like. However, the present disclosure is not limited to those methods. 
     In such a manner, in this embodiment, in a case where the obstacle detected by the robot  1  is an object and the behavior type of the robot  1  in detection of the obstacle is behavior such as “random travel” or “movement to the charger” which is performed when whether the user is present around is unknown, it is difficult for the robot  1  to increase opportunities of communication with the user. Thus, the main controller  107  outputs the behavior control command for avoiding collision with an object as a minimum action to the driving mechanism controller  116 . Accordingly, collision between the robot  1  and an object and damage to either one or both of those may be prevented. 
     Note that the behavior control command in a case of avoiding an obstacle is not limited to this. For example, in addition to this behavior control command, the main controller  107  may output, to the display controller  112  and the sound controller  114 , the behavior control command for lighting the plural light emitting diodes of the display  111  that are positioned at the coordinates for reproducing a predetermined facial expression (for example, a surprised face, a sad face, and so forth) and the behavior control command for causing the robot  1  to utter a predetermined sound (for example, “oops”, “that was close”, “something might be there”, and so forth), respectively. 
     On the other hand, in a case where the determination result in step S 211  is not “random travel” (a case of “No” in S 211 ), the main controller  107  determines whether or not the present behavior type of the robot  1  is “approach to the user” from the behavior type information  132  of the robot  1  acquired in step S 203  (S 213 ). 
     In a case where the determination result in step S 213  is “approach to the user” (a case of “Yes” in S 213 ), the main controller  107  outputs the behavior control command, by which the robot  1  conducts “obstacle removal inducing utterance” for the user, to the display controller  112  and the sound controller  114  (S 214 ) and terminates the obstacle handling process. 
     A specific example of “obstacle removal inducing utterance” is as follows. The main controller  107  outputs, to the display controller  112 , the behavior control command for lighting the plural light emitting diodes of the display  111 , which are positioned at the coordinates which enable reproduction of a facial expression of asking for help (for example, both eyes in the shape of “&gt;&lt;” or the like) as illustrated in the second row and second column of table H 6  in  FIG. 6 . Further, the main controller  107  outputs, to the sound controller  114 , the behavior control command that causes the robot  1  to utter a sound with a content by which the robot  1  induces the user to move the obstacle away such as “move the obstacle away”, for example, as illustrated in the second row and second column of table H 6  in  FIG. 6 . Then, when output of all the behavior control commands is completed, the main controller  107  terminates the obstacle handling process. 
     In such a manner, in this embodiment, in a case where the obstacle detected by the robot  1  is an object and the behavior of the robot  1  in detection of the obstacle is behavior such as “approach to the user” or “movement in conversation” which is performed when the possibility that the user is present around is high, “obstacle removal inducing utterance” that encourages the user to move the obstacle away is performed. Accordingly, opportunities of communication between the robot  1  and the user may be increased as much as possible. 
     Note that the facial expressions and the sounds of the robot  1 , which are described here, are examples, and the facial expressions and the sounds are not limited to those. For example, the main controller  107  may output only the behavior control command that causes the robot  1  to utter a sound to the sound controller  114 . In this case, communication between the robot  1  and the user may be made only by the sound output from the speaker  113 . Further, the main controller  107  may output only the behavior control command for displaying text information, in which the sound uttered by the robot  1  is displayed as text, as a facial expression to the display controller  112 . In this case, communication between the robot  1  and the user may be made only by the text information displayed on the display  111 . Further, the main controller  107  may output the behavior control command for outputting both a sound and the text information of the sound to the display controller  112  and the sound controller  114 . In this case, communication between the robot  1  and the user may be made by using the sound and the text information. 
     Furthermore, in addition to or instead of the sound and the facial expression of the robot  1 , the main controller  107  may output, to the driving mechanism controller  116 , the behavior control command that causes the robot  1  to make a predetermined motion (for example, sway in the left-right direction, a nod in the up-down direction, and so forth) and may thereby cause the robot  1  to perform a gesture that indicates that the robot  1  desires removal of the obstacle. In this case, the robot  1  may more effectively induce the user to remove the obstacle by using a motion as well. 
     On the other hand, in a case where the determination result in step S 213  is not “approach to the user” (a case of “No” in S 213 ), the main controller  107  determines whether or not the present behavior type of the robot  1  is “movement to the charger” from the behavior type information  132  acquired in step S 203  (S 215 ). 
     In a case where the determination result in step S 215  is “movement to the charger” (a case of “Yes” in S 215 ), the process moves to above-described step S 212 , behavior for avoiding the obstacle is executed, and the obstacle handling process is thereafter terminated. 
     On the other hand, in a case where the determination result in step S 215  is not “movement to the charger” (a case of “No” in S 215 ), that is, is not any of “random travel”, “approach to the user”, and “movement to the charger” but is “movement in conversation”, the process moves to above-described step S 214 , the obstacle removal inducing utterance is executed, and the obstacle handling process is thereafter terminated. 
     Next, a summary of the obstacle handling process indicated by the flow of  FIG. 5  will be described.  FIG. 6  is a diagram that summarizes the obstacle handling process. The left side of  FIG. 6  illustrates behavior of the robot  1  in a case where an obstacle is detected, and the right side of  FIG. 6  illustrates table H 6  that summarizes behavior which may be made by the robot  1  in the obstacle handling process. 
     In step S 601  in  FIG. 6 , the robot  1  makes any behavior of “random travel”, “approach to the user”, “movement to the charger”, and “movement in conversation”. In step S 602 , the robot  1  detects an obstacle and thus stops in a predetermined distance to the obstacle. In step S 603 , the robot  1  distinguishes which of the user or an object the type of the obstacle corresponds to. Then, the robot  1  makes the behavior illustrated in table H 6  in accordance with the behavior type in S 601  and the type of the obstacle detected in S 603 . 
     As illustrated in the first row of table H 6 , in a case where the behavior type is “random travel” and where the obstacle is “user”, the robot  1  performs “conversation inducing utterance” that encourages a user U 1  to have conversation such as “play with me”. This is for increasing opportunities of communication with the user U 1  by utterance to the user U 1  because the user U 1  is found in the random travel and it is obvious that the user U 1  is present around the robot  1 . On the other hand, when the obstacle is “object”, the robot  1  avoids the object. This is because the user U 1  is not found in the random travel, it is unknown whether or not the user U 1  is present around the robot  1 , and it is difficult to have communication with the user U 1 . 
     As illustrated in the second row of table H 6 , in a case where the behavior type is “approach to the user” and where the obstacle is “user”, the robot  1  performs “conversation inducing utterance”. This is for increasing opportunities of communication with the user U 1  by active utterance from the robot  1  to the user U 1  because it is obvious that the user U 1  is present around the robot  1 . On the other hand, when the obstacle is “object”, the robot  1  performs “obstacle removal inducing utterance” that encourages the user U 1  to move the obstacle away such as “move the obstacle away”. This is because it is obvious that the user U 1  is present around the robot  1  and opportunities of communication with the user U 1  are increased more by encouraging the user U 1  to remove the obstacle than a case where the robot  1  simply performs behavior for avoiding the obstacle. 
     As illustrated in the third row of table H 6 , in a case where the behavior type is “movement to the charger” and where the obstacle is “user”, the robot  1  performs “charging inducing utterance” that encourages the user U 1  to return the robot  1  to the charger  2  such as “return me to the charger”. This is because it is obvious that the user U 1  is present around the robot  1  and opportunities of communication with the user U 1  are increased more by being returned to the charger  2  by the user U 1  than autonomous movement to the charger  2 . On the other hand, in a case where the obstacle is “object”, the robot  1  makes behavior for avoiding the object. This is because it is unknown whether or not the user U 1  is present around the robot  1  and it is difficult to have communication with the user U 1 . 
     As illustrated in the fourth row of table H 6 , in a case where the behavior type is “movement in conversation” and where the obstacle is “user”, the robot  1  performs “reaction utterance” such as “I am happy being beside you”. This is for increasing opportunities of communication between the robot  1  and the user U 1  by active utterance from the robot  1  to the user U 1  because the user U 1  and the robot  1  are already having conversation. On the other hand, in a case where the obstacle is “object”, the robot  1  performs “obstacle removal inducing utterance”. This is because the robot  1  is having conversation with the user U 1 , conversation with the user U 1  is promoted by using presence of “object” as a trigger, and an increase in opportunities of communication between the user U 1  and the robot  1  is thereby intended. 
     As illustrated in table H 6 , it may be understood that patterns in which the robot  1  and the user U 1  do not communicate are two patterns that are the pattern of the first row and second column and the pattern of the third row and second column and in the patterns other than those, the robot  1  and user U 1  have some kinds of communication and behavior of the robot  1  is controlled so as to increase opportunities of communication as much as possible. Note that in table H 6 , each of “conversation inducing utterance”, “charging inducing utterance”, “reaction utterance”, and “obstacle removal inducing utterance” is one example of first behavior that increases opportunities of interaction with the user U 1 . Further, “avoidance” corresponds to one example of second behavior for handling an obstacle. 
     As described above, in this embodiment, switching is made between the first behavior for increasing opportunities of interaction with a user and the second behavior for avoiding an obstacle in accordance with the behavior type of the robot  1  in detection of an obstacle and the type of the obstacle. Thus, in this embodiment, an obstacle may be avoided while opportunities of communication between the robot  1  and the user are increased as much as possible. 
     Note that the present disclosure may employ the following modification examples. 
     (1) In this embodiment, a description is made while children and parents are together categorized as users. However, this is one example, and the main controller  107  may change utterance contents of the robot  1  in the above-described obstacle handling process in a case where the user is a child and a case where the user is a parent. In this case, the main controller  107  may determine whether the user is a parent or a child from the attribute information of the user (for example, a user ID, an age, and so forth) included in the video analysis results acquired from the video processor  102 . 
     For example, in the above-described “conversation inducing utterance”, in a case where the user is a child, the main controller  107  conducts utterance such as “play with me” as described above. Accordingly, opportunities of communication between the robot  1  and the child may be increased as much as possible. 
     On the other hand, in a case where the user detected in “random travel” is a parent, the main controller  107  outputs the behavior control command, by which the robot  1  conducts utterance for inducing assistance for avoidance by the robot  1  such as “step aside”, to the sound controller  114 . Accordingly, the robot  1  may avoid the obstacle as an object while having communication with the parent. 
     Note that instead of utterance of “step aside”, the main controller  107  may output the behavior control command that causes the robot  1  to perform a gesture which indicates that the robot  1  desires movement away from the robot  1 . In this case, the main controller  107  may output the behavior control command for swaying the robot  1  in the left-right direction to the driving mechanism controller  116 . For example, the main controller  107  may output the behavior control command for outputting the facial expression of a worried face to the display  111  to the display controller  112 . 
     (2) An example where the contact information DB  131  is not utilized is described in the flow of  FIG. 5 . However, the present disclosure is not limited to this, and a handling method for an obstacle may be changed by utilizing the contact information DB  131 . For example, it is assumed that in a case where the user is detected in step S 204 , the main controller  107  specifies the contact time between the detected user and the robot  1  in a predetermined period based on the contact information DB  131  and the contact time is a predetermined threshold value or greater. In this case, when the behavior type of the robot  1  is “random travel” or “approach to the user”, the main controller  107  does not conduct “conversation inducing utterance” but may conduct behavior for avoiding the user. For example, in a case where sufficient contact time between the robot  1  and a child has already been spent, some parents possibly do not desire continuance of contact between the robot  1  and the child. Thus, the present disclosure causes the robot  1  to make behavior for avoiding the user in consideration of intention of such parents. 
     Specifically, in a case where it is determined that the obstacle is the user in step S 204 , the main controller  107  specifies the user ID of the concerned user from the attribute information of the user included in the video analysis results output from the video processor  102 . Then, the main controller  107  requests the management unit  108  to perform a process for extracting the contact information of the concerned user in a specific past period (for example, one day, half a day, six hours, and so forth) from the present time from the contact information DB  131  and thereby acquires the contact information in the specific past period from the present time. Then, the main controller  107  uses the data stored in the column of “contact date and time” of the acquired contact information and thereby calculates the total contact time of the concerned user in the specific past time from the present time. Then, in a case where the total contact time is a predetermined threshold value or greater and where the present behavior type of the robot  1  is “random travel” or “approach to the user”, the main controller  107  may output the behavior control command for avoiding the user to the driving mechanism controller  116 . 
     Here, the contact time between the robot  1  and a child is used, but the present disclosure is not limited to this. For example, the main controller  107  may employ the contact frequency between the robot  1  and a child in a predetermined time. In a case where this mode is employed, the contact information DB  131  includes a column of the above-described “contact frequency”. The main controller  107  uses the data stored in the column of “contact frequency” of the contact information of the concerned user in a specific past period from the present time, which is acquired from the management unit  108 , and thereby obtains the total contact frequency of the concerned user in the specific past time. Then, in a case where the total contact frequency is a predetermined threshold value or greater, the main controller  107  may output the behavior control command for avoiding the user to the driving mechanism controller  116 . 
     Further, the main controller  107  may utilize a facial expression, a sound, or a kind of an operation of a child in contact with the robot  1  and use positive expressions (for example, facial expressions such as “smiling face” and “surprised face”, sounds such as “I like you” and “play more”, operations such as “touching” and “stroking”, and so forth) instead of the contact time. 
     In a case where this mode is employed, the main controller  107  refers to the data stored in the column of “contact content” of the contact information of the concerned user in a specific past period from the present time, which is acquired from the management unit  108 , and thereby tallies the total number of pieces of contact information in which the positive expressions are stored. Then, in a case where the tallied total number is a predetermined threshold value or greater, the main controller  107  may output the behavior control command for avoiding the user to the driving mechanism controller  116 . 
     (3) In step S 201 , in a case where detection of an obstacle and identification of the type of an obstacle are simultaneously performed, the time before the robot  1  stops may be changed in accordance with the type of the obstacle. For example, in a case where the type of the detected obstacle is the user and where the distance from the present position to the user is a predetermined separation distance or longer, in which the robot  1  is capable of interacting with the user, the main controller  107  outputs the behavior control command that causes the robot  1  to travel at a higher speed than a usual traveling speed to the driving mechanism controller  116 . Then, when the robot  1  arrives at the position in a predetermined distance to the user, the main controller  107  outputs the behavior control command for stopping travel of the robot  1  to the driving mechanism control unit  116 . Accordingly, the robot  1  may come close to the user at a higher speed than usual, and the robot  1  may be caused to behave as if the robot  1  were a pet that ran to the owner. On the other hand, in a case where the distance to the user is the predetermined distance or shorter when the user is detected, the main control unit  107  may output the behavior control command for stopping travel of the robot  1  to the driving mechanism control unit  116  and thereby stop travel of the robot  1  quickly. 
     (4) In the above embodiment, the robot  1  is the spherical robot illustrated in  FIG. 1 . However, the present disclosure is not limited to this, and a biped walking robot, a quadruped walking robot, a robot that moves by wheels, and so forth, which are other than the spherical robot, are possible. 
     A robot according to an exemplary embodiment of the present disclosure is useful for avoidance of an obstacle that is performed by a robot while opportunities of communication between a robot and a user are increased as much as possible.