Abstract:
The present invention addresses the problem of achieving an autonomous mobile system that is provided with a means for safe two-way traffic or overtaking if the crossing or approach of travel paths arises with respect to another party such as a pedestrian, bicycle or the like during autonomous travel over a designated reference path in an environment in which mobile obstacles such as pedestrians, bicycles and the like moving in free directions are present in public or in a facility. To solve this problem, in the present invention, it is necessary before an approach to induce circumstances such that mutual motion is defined and to obtain defining information of the movement of the other party, thereby maintaining uniform circumstances when passing nearby such that no large changes in course are performed. Consequently, if the crossing or approach of travel paths arises with respect to another party such as a pedestrian, bicycle or the like, the autonomous mobile system behaves in a manner easy to predict by the other party in order to induce circumstances such that the movement of the other party is defined, and after obtaining the defining information of the movement of the other party, maintains uniform circumstances when passing nearby such that no large changes in course are performed, thereby achieving safe and secure two-way traffic and overtaking.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to an autonomous mobile system that autonomously travels over a designated reference path in an environment in which a mobile obstacle, such as a pedestrian or a bicycle that moves, is present in a facility or in public. 
       BACKGROUND ART 
       [0002]    As the background art of the present technical field, PTL 1 has been disclosed. In the publication, an object is to provide an autonomous mobile object creating a travel path for moving autonomously while avoiding a collision with a mobile obstacle. Therefore, the following method and system have been disclosed. Based on current position information and travel direction information of the mobile obstacle, a travel prediction path of the mobile obstacle is calculated. A restricted region is set around a future position of the mobile obstacle at a point in time at which the autonomous mobile object arrives at an intersection between the path and the travel path of the autonomous mobile object. The larger a distance between the current position of the autonomous mobile object and the future position of the mobile obstacle, is, the smaller the restricted region is set. The travel path of the autonomous mobile object is created so as to avoid the restricted region. 
         [0003]    PTL 2 discloses a travel path creating method and a system including the following. A size of the restricted region of the mobile obstacle disclosed in PTL 1 is set so as to be small as a relative distance between the mobile obstacle and the autonomous mobile object increases. The size of the restricted region is set so as to be large as the speed of the autonomous mobile object increases. 
       CITATION LIST 
     Patent Literature 
       [0004]    PTL 1: Japanese Patent Application Laid-Open No 2008-152600 
         [0005]    PTL 2: Japanese Patent Application Laid-Open No. 2008-152599 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0006]    An object of the present invention is to provide an autonomous mobile system including a unit for performing secure two-way traffic or overtaking traffic in a case where crossing or approach of a travel path occurs with respect to the other party, such as a pedestrian, a bicycle, or the like, upon autonomous travel over a designated reference path in an environment in which a mobile obstacle, such as a pedestrian or a bicycle that moves, is present in a facility or in public. 
         [0007]    The system in PTL 1 predicts the future position of the mobile obstacle based on the current position information and the travel direction information of the mobile obstacle, and changes the path of the autonomous mobile object. Thus, in a case where the mobile obstacle includes a plurality of pedestrians or bicycles, when one of them changes a speed and a travel direction in an instant, the autonomous mobile object changes in course. Therefore, there are the following problems. A sudden change in course or a frequent change in course of the autonomous mobile object occurs. The pedestrians or the bicycles cannot predict a movement of the autonomous mobile object. The pedestrians or the bicycles also change in course. Secure/safe two-way traffic and overtaking traffic cannot be achieved. 
         [0008]    In the system in PTL 2, the size of the restricted region of the mobile obstacle is set so as to be small as the relative distance between the mobile obstacle and the autonomous mobile object increases. The size of the restricted region is set so as to be large as the speed of the autonomous mobile object increases. Thus, an effect of the distant mobile obstacle becomes small. However, an avoidance width increases as the mobile obstacle comes close and the speed of the autonomous mobile object increases. Thus, a large change in direction is required. Therefore, there is a case where a large change in course occurs when the autonomous mobile object is close to the mobile obstacle, and there is a problem that secure two-way traffic and overtaking traffic cannot be achieved. 
         [0009]    In contrast, the present invention has been made in order to solve the above conventional problems. An object of the present invention is to provide an autonomous mobile system capable of achieving secure two-way traffic and overtaking traffic with respect to a mobile obstacle, such as a pedestrian or a bicycle that moves in a free direction. 
       Solution to Problem 
       [0010]    In order to solve the above problems, according to the present invention, an autonomous mobile system is configured to autonomously move based on a designated reference path in an environment in which an obstacle is present. The autonomous mobile system includes: an environment information acquisition unit configured to acquire environment information of circumstances; a storage information processing unit configured to retain the reference path information or geographic information in which the reference path has been registered; a self-position estimation unit configured to estimate a self-position of the autonomous mobile system based on the environment information and the reference path information or the geographic information; an obstacle information generating unit configured to generate information of an obstacle preventing the movement, based on the environment information; a path determining unit configured to determine a travel direction and a travel speed based on the self-position, the obstacle information, and the reference path information; an approach movement generating unit configured to determine a travel path, a travel direction, or a travel speed for inducing stable circumstances in which mutual movements have been previously defined, in a case where a mobile object approaches based on the obstacle information; and a vehicle control unit configured to control the movement of the autonomous mobile system based on the travel direction and the travel speed. The approach movement generating unit detects approach of the mobile object and the autonomous mobile system, determines types of approach circumstances based the obstacle information of the mobile object, a current position of the autonomous mobile system, and the reference path, determines a prediction-facilitating movement in which the movement of the autonomous mobile system is easily predicted by the mobile object, based on the types of approach circumstances, determines route definition of the mobile object based on a certain movement of the mobile object during a certain period during the prediction-facilitating movement, and corrects a route of the autonomous mobile system so that a route of the mobile object is not prevented, based on the defined route of the mobile object. 
         [0011]    Further, in the autonomous mobile system according to the present invention, the prediction-facilitating movement generates a rectangular section and a travel speed based on circumstances of the environment, an approach position, and the types of approach circumstances, and travels at a constant speed in the generated rectangular section. 
         [0012]    Still further, in the autonomous mobile system according to the present invention, the types of approach circumstances include any of two-way travel, crossing, overtaking, and catching-up, and the prediction-facilitating movement weights selection of the speed and the path in response to the types. 
         [0013]    Another still further, in the autonomous mobile system according to the present invention, the mobile object is a pedestrian or a bicycle, and the obstacle information generating unit generates identifiable information. 
       Advantageous Effects of Invention 
       [0014]    According to the present invention, an autonomous mobile system capable of performing secure two-way traffic and overtaking traffic with respect to a mobile obstacle, such as a pedestrian or a bicycle that moves, can be provided 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0015]      FIG. 1  is a diagram of a system configuration of an autonomous mobile system according to one embodiment of the present invention. 
           [0016]      FIG. 2  is a flowchart of processing of an approach movement generating unit according to one embodiment of the present invention. 
           [0017]      FIG. 3  is a conceptual diagram of approach-detection according to one embodiment of the present invention. 
           [0018]      FIG. 4  is a conceptual diagram of types of approach circumstances according to one embodiment of the present invention. 
           [0019]      FIG. 5  is a conceptual diagram of a prediction-facilitating movement according to one embodiment of the present invention. 
           [0020]      FIG. 6  is a conceptual diagram of a self-route correction and approach travel according to one embodiment of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0021]    An exemplary autonomous mobile system according to a preferred embodiment of the present invention, will be described below based on the drawings. 
         [0022]    According to the present embodiment, an example of the autonomous mobile system including an approach movement generating unit, will be described. In order to perform secure/safe two-way traffic and overtaking traffic in a case where crossing or approach of a travel path occurs with respect to the other party, such as a pedestrian or a bicycle, upon autonomous travel over a designated reference path in an environment in which a mobile obstacle, such as a pedestrian or a bicycle, that moves in a free direction, is present in a facility or in public, the approach movement generating unit behaves so as to be easily predicted by the other party in order to induce circumstances in which a movement of the other party has been defined. After acquiring definition information of the movement of the other party, the approach movement generating unit maintains uniform circumstances when passing nearby so that no large change in course is performed. Note that, the present invention is suitable to an environment which a mobile obstacle, such as a pedestrian or a bicycle, is present. The present invention can be also applied to an environment in which a mobile object, such as a motor vehicle or a carrier, operated by a person, and an autonomous mobile system are present. 
         [0023]      FIG. 1  is a diagram of a configuration of the autonomous mobile system according to the present embodiment. The detailed descriptions will be given below using reference signs. 
         [0024]    The autonomous mobile system  100  includes a storage information processing unit  110 , an environment information acquisition unit  112 , self-position estimation unit  114 , an obstacle detecting unit  116 , a path determining unit  118 , an approach movement generating unit  120 , and a vehicle control unit  122 . Note that, not illustrated, a configuration in which each of the above units is performed on a computer equipped in the autonomous mobile system  100 , can be provided. Alternatively, a configuration in which processing of a part or all of the units is performed on an external computer through wireless communication, can be provided. The autonomous mobile system according to the present embodiment, will be described below as a configuration in which the autonomous mobile system moves using wheels. 
         [0025]    The storage information processing unit  110  retains a reference path over which at least the autonomous mobile system  100  travels, and geographic information on the periphery of the path. The storage information processing unit  110  transmits the geographic information on the periphery of the path to the self-position estimation unit  114 , and transmits the reference path to the path determining unit  118 . 
         [0026]    The environment information acquisition unit  112  includes a sensor equipped in the autonomous mobile system  100 , and acquires information from the sensor. The detail of the sensor is not illustrated. The sensor includes a laser-typed distance sensor, a camera (for example, a stereo camera system having a configuration in which two cameras are arranged side by side so as to capable of measuring a distance), an angular velocity sensor, an acceleration sensor, a magnetic sensor, a GPS receiver, a wheel rotational quantity sensor, and the like. Pieces of sensor information acquired by the sensors are transmitted to the self-position estimation unit  114  and the obstacle detecting unit  116  to be descried later. 
         [0027]    The self-position estimation unit  114  specifies a current position of the autonomous mobile system  100  based on the pieces of information acquired by the respective sensors. For example, in detail, self-position information created by accumulating a value of the wheel rotational quantity sensor (referred to as an odometry), a correction of the odometry by the angular velocity sensor, the acceleration sensor, and the magnetic sensor, self-position information acquired by associating information from the laser-typed distance sensor and the camera with the geographic information acquired from the storage information processing unit  110 , and position information acquired from the GPS receiver, are stochastically merged (for example, by adopting a method referred to as an extended Kalman filter) so that accurate own position and direction are estimated in a region in which the autonomous mobile system  100  moves. Self-position data that has been finally acquired is transmitted to the obstacle detecting unit  116  and the path determining unit  118  to be described later. 
         [0028]    Based on the pieces of information from the sensors, the obstacle detecting unit  116  detects a region to be an obstacle with respect to a movement of the autonomous mobile system  100 , and calculates obstacle information. For example, in detail, examples of the obstacle include a step having a height over which the autonomous mobile system  100  cannot cross, a large groove, a protruding portion in the air, or the like, in peripheral shape information acquired from the laser-typed sensor and the camera (for example, a stereo camera system having a configuration in which two camera are arranged side by side stereo so as to capable of measuring a distance). An obstacle, such as a pedestrian or a bicycle (in some cases, a motor vehicle) that moves and is present in an environment, such as in a facility or in public, is also detected, the obstacle being an object according to the present invention. In particular, the pedestrian or the bicycle (in some cases, the motor vehicle) is specified by using, for example, image processing. Obstacle information on the obstacle that moves, includes a size (width), a travel speed, and a travel direction, and the like. 
         [0029]    Based on the above self-position information, a reference path to be traveled, the obstacle information, such as types of obstacles that have been detected (mobile obstacles: an animal, a ball, or a leaf, stationary obstacles: a step, a pole, a hedge, or the like), a position, a shape, a speed, and the like, the path determining unit  118  determines and transmits a target path or a target direction and a speed of the autonomous mobile system  100  to the approach movement generating unit  120 . 
         [0030]    In a case where a pedestrian or a bicycle (in some cases, a motor vehicle) has been detected as a mobile obstacle based on the above obstacle information, the approach movement generating unit  120  determines a target speed and a target direction of the autonomous mobile system  100  for behaving so as to be easily predicted by the other party in order to induce circumferences in which a movement of the other party has been defined, and for maintaining stable and uniform circumferences so that no large change in course is performed when passing nearby, after acquiring the definition information of the movement of the other party, in order to perform safe/secure two-way traffic or overtaking traffic by processes to be described later in a case where crossing or approach of a travel path occurs with respect to the other party, such as a pedestrian or a bicycle. 
         [0031]    The vehicle control unit  122  performs motion control of the vehicle based on the target direction and the target speed of the autonomous mobile system  100  that have been acquired from the approach movement generating unit  120 . In particular, for example, control is performed so that a difference between a current travel direction/travel speed of the autonomous mobile system  100  and the target direction/target speed decreases. The vehicle control unit  122  includes a driving source, such as a motor or an engine, and an electronic circuit for controlling the wheels, and is capable of changing a position and a direction of the autonomous mobile system  100 . 
         [0032]      FIG. 2  is a flow chart of processing of the approach movement generating unit  120  in  FIG. 1 . The descriptions will be given below using reference signs. Processing of each block in the flow chart will be described in detail using  FIGS. 3, 4, 5, and 6 . 
         [0033]    The approach movement generating unit  120  first performs approach-detection with respect to a pedestrian or a bicycle (hereinafter, referred to as a mobile object) as Step  101  in  FIG. 2  (hereinafter, referred to as S 101 ). As illustrated in  FIG. 3 , a path  202  of the mobile object  201  is assumed based on the obstacle information from the obstacle detecting unit  116 . A case where an interval  206  (approach distance) with respect to a path  202  of the autonomous mobile system  100  acquired from the path determining unit  118  is a predetermined value or less, is detected. The approach distance may be approximate. The paths are given as positions at predetermined time intervals. The interval  206  between positions (position  204 , position  205 ) at certain time is calculated. In this case, a closest approach point may be acquired by interpolating positions at time intervals. As the approach distance, an interval between positions (position  204 , position  205 ) may be used. The path  202  of the mobile object  201  has been illustrated by a curve as a target path in  FIG. 3 . A straight line using a current position, a travel speed, a travel direction, may be used. 
         [0034]    Next, the approach movement generating unit  120  performs an approach-circumstances analysis with respect to the mobile object as  5102  in  FIG. 2 . As illustrated in  FIG. 4 , types of approach circumstances include facing  210 , front-crossing  211   a , back-crossing  211   b,  overtaking  212 , and catching-up  213 , depending on a travel direction and a travel speed of the mobile object. 
         [0035]    Next, as S 103  in  FIG. 2 , the approach movement generating unit  120  determines a prediction-facilitating movement for causing the mobile object to easily predict a movement of the autonomous mobile system  100 . As illustrated in  FIG. 5 , sections ( 221  to  223 ) each in which the prediction-facilitating movement is performed, are set with respect to the current target path  202 . Linearly traveling is preferable in the sections in order to cause the other party to easily predict the movement of the autonomous mobile system  100 . In  FIG. 5 , the sections have been illustrated by rectangles. A path including a gentle and constant curvature or a section of a following-path including a gentle change along a boundary of a sidewalk, may be provided. Lengths of the sections are determined by presence of an obstacle, a closest approach predicting position, or the like. The autonomous mobile system  100  determines a speed in response to sizes of the sections, a speed of the mobile object, the above approach circumstances. 
         [0036]    Determination of the sections is selected in response to current circumstances. For example, in a case where the mobile object is present ahead and a change in course involves danger, the section  221  is selected and the autonomous mobile system  100  decelerates or stops in response to the length of the section. In a case where a slight change in course is required, the section  222  parallel to the current travel direction, is selected. In a case where a large change-direction is required in a change in course, the section  223  having a slight angle change with respect to the current direction, may be selected. Note that, the angle change is performed for a short time so as to be small in order to cause the other party to easily predict the movement. 
         [0037]    Selection of the prediction-facilitating movement is weighted in response to the above approach circumstances. In a case of the facing  210 , in order to define which the mobile object travels to the left side or the right side of the autonomous mobile system  100 , a deceleration movement is performed for accelerating a change in route of the mobile object, and the section  222 , parallel to the current travel direction, for shifting a route axis with respect to the facing mobile object, is selected. 
         [0038]    In a case of the above front-crossing  211   a,  a deceleration for accelerating definition of the circumstances is performed. In a case of the back-crossing  211   b,  a forward movement without the deceleration for accelerating the definition of the circumstances, is performed. In a case of the overtaking  212 , a deceleration and a stop for giving a route are performed and the parallel section  222  is selected. In a case of the catching-up  213 , a section parallel to a travel direction of the other party is highly weighted in order not to give an effect to a movement of the other party after overtaking. In a case where the prediction-facilitating movement has been already being performed and an approach movement to be described later has been already being performed, and in a case where a plurality of mobile objects is present, a severe condition is selected with respect to the mobile objects. 
         [0039]    Note that the above determination of the prediction-facilitating movement is one embodiment for solving the problems according to the present invention. If the movement of the autonomous mobile system  100  is easily predicted, a method including the above following-path travel, speed change, and slight change in course combined, may be provided. 
         [0040]    Next, as S 104  in  FIG. 2 , the approach movement generating unit  120  performs definition-determination of the other party&#39;s route. Here, in a case where the latest travel circumstances of the other party have a constant and linear movement-section, the route is definition-determined as the other party&#39;s route. The route definition may not be a perfect straight line, and is detected by entering in a rectangular region in which a travel locus of the other party has a certain width and length. In a manner similar to the route, it is determined that a speed has been defined when a variation is a predetermined value or less during the latest certain period. In a case where the definition-determination cannot be performed even when a predetermined period has passed, there is a case where approach circumstances vary. Thus, determination is performed at S 105  in  FIG. 2 . The processing goes back to the approach-detection S 101  and new processing is performed under the latest circumstances. 
         [0041]    The approach movement generating unit  120  finally performs a correction of a self-route and approach travel so that the route of the mobile object is not prevented as S 106  in  FIG. 2  in a case where it is determined that the route of the other party has been defined at S 105 . 
         [0042]    As illustrated in  FIG. 6 , in a case where the autonomous mobile system  100  travels over the above prediction-facilitating movement section  230 , induces route definition of the facing  210  of the mobile object, and definition-determines a route  231  under the latest travel circumstances of a travel locus  233  of the mobile object, the autonomous mobile system  100  promptly and slightly corrects the self-route, and travels over a route  232  for performing safe/secure two-way traffic. Here, the two-way traffic has been illustrated in  FIG. 6 . The same is true of other circumstances, such as the overtaking or the crossing. Accordingly, in a case where the mobile object is approached, since the mutual movements have been defined, safe/secure traffic can be performed. 
         [0043]    Finally, in a case where a sequence of the approach movement illustrated in  FIG. 2  has been completed and a mobile object has not been detected by the obstacle detecting unit  116 , the approach movement generating unit  120  transmits a target path or a target direction and a speed that have been generated by the path determining unit  118 , to the vehicle control unit  122 . 
       REFERENCE SIGNS LIST 
       [0000]    
       
           100  autonomous mobile system 
           110  storage information processing unit 
           112  environment information acquisition unit 
           114  self-position estimation unit 
           116  obstacle detecting unit 
           118  path determining unit 
           120  approach movement generating unit 
           122  vehicle control unit