Abstract:
A robot, capable of appropriately adjusting position and/or posture on a current spot to execute a designated task involving interaction with a target object. 
     The Robot is configured to enable adjustment of the position and/or posture by controlling movement of at least a hip joint mechanism, and a knee joint mechanism in the spot while the robot is allowing each foot to keep its floor-arriving state. Accordingly, when the position and/or posture is inappropriate to execute the designated task while the robot is at a standstill in a second designated area for executing the designated task, the robot can execute the designated task after the position and/or posture has been corrected in the second designated area.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a robot which is capable of autonomously moving by the operation of a plurality of legs extending from a body. 
         [0003]    2. Description of the Related Art 
         [0004]    There has been proposed a technique for carrying out charging of a battery mounted on an autonomously movable robot (refer to Japanese Patent Application Laid-Open No. 2007-245332). According to this technique, a reliable connection between a first connector provided for a body of the robot and a second connector that is owned by a charging installation is attained by moving the robot so as to be guided by a guide member on the side of a battery charge station. 
         [0005]    Meanwhile, as a method of connecting the first connector and the second connector, in addition to the method in which the robot is moved relative to the charging installation, it may be possible to contemplate a method of driving the second connector by a drive provided for the charging installation so as to be brought close to the first connector in a state where the robot has been stopped. 
         [0006]    However, in the second-mentioned method, the position or the like of the first connector may become inappropriate from a viewpoint of connection with the second connector because of the fact that the position, posture, or position and posture (hereinafter properly referred to as “position or the like”) of the second connector undesirably deviates from its inherent or original position and the like, or for the reason that there are inconvenient factors, such as inclination of a floor, or existence of irregularities in a floor on which the robot is positioned even though the robot stops with a designated posture in a designated position (or the robot per se recognizes that it stops with a designated posture in a designated position). In this case, even if the robot is once moved to another position and is thereafter moved back to a designated position thereof, and has stopped with a designated posture in this designated position, the position or the like of the first connector may still remain unsuitable from a viewpoint of connection with the second connector. Additionally, when this moving distance becomes long, it is not preferable from a viewpoint of saving of consumption in energy of the robot. 
       SUMMARY OF THE INVENTION 
       [0007]    Therefore, an object of the invention is to provide a robot capable of suitably adjusting the position or the like of its body on the current spot from a viewpoint of executing a designated task accompanied by the interaction with a target object. 
         [0008]    The present invention is concerned with a robot which includes a body, a plurality of legs connected to the body via a first leg joint mechanism, respectively, and having a second leg joint mechanism, respectively, and a controller, the robot being autonomously movable with repetition of causing the plurality of legs thereof to leave from and arrive at a floor (it will be hereinafter referred to as “floor-leaving and “floor-arriving” throughout the present application) as the movement of a leg joint mechanism group including the first leg joint mechanism and the second leg joint mechanism is controlled by the controller. 
         [0009]    In the robot of the first aspect of the present invention, the controller is characterized by comprising a first control element which determines whether or not a second position/posture requirement is satisfied that the position and posture of the body fall within a second target position range and a second target posture range, respectively, which are defined from a viewpoint that the robot is urged to execute a designated task, in a state where the robot is in standstill in a second designated area which is an execution area of the designated task accompanied by an interaction thereof with a target object, and a second control element which controls the movement of the leg joint mechanism group to change the position, posture, or position and posture of the body while the plurality of legs are kept arriving at the floor, under a requirement that the first control element determines that the second position/posture requirement has not yet been satisfied. 
         [0010]    In accordance with the robot of the first aspect of the present invention, while the robot maintains each foot to keep a state of arriving at the floor, the position or the like of the body is adjusted by controlling the movement of the leg joint mechanism group which comprises the first leg joint mechanism and the second leg joint mechanism, on a current spot of the robot, under a requirement that the “second position/posture requirement” is not satisfied. Accordingly, in a case where the position or the like of the body is inappropriate from a viewpoint of executing the designated task notwithstanding that the robot stops in the second designated area in order to execute the designated task, the robot can execute the designated task after the position or the like of the body has been corrected on the current spot in the second designated area. At this stage, the “movement” of respective of the joint mechanism technically means movements which are defined by a part of or all of translational movements in the directions of three axes and rotations about the three axes in a rectangular coordinate system. The “robot stops” technically means a state where the movements of all of the leg joint mechanisms which belong to the leg joint mechanism group are stopped. 
         [0011]    A robot of a second aspect of the present invention is characterized in that, with the robot of first aspect of the present invention, there is further provided a plurality of feet as floor-arriving portions of the plurality of legs, which are respectively connected to ends of the plurality of legs via a third leg joint mechanism, and the second control element controls the movement of the leg joint mechanism group including the third leg joint mechanism in addition to the first leg joint mechanism and the second leg joint mechanism. 
         [0012]    In accordance with the robot of the second aspect of the present invention, the position as well as the variable range of a posture of the body can be flexibly extended by moving the third leg joint mechanism in addition to the first leg joint mechanism and the second leg joint mechanism. 
         [0013]    A robot of a third aspect of the present invention is characterized in that, with the robot of the first aspect of the present invention the first control element determines whether or not a correction requirement is satisfied that the second position/posture requirement is satisfied by executing a correction such that the position and posture of the body may not exceed a variable position range and a variable posture range, respectively, which are defined from a viewpoint such that the robot is permitted to stably stand, depending on the movement of the leg joint mechanism group while the robot permits the plurality of legs to be kept arriving at a floor, and the second control element controls the movement of the leg joint mechanism group so as to change the position, posture, or position and posture of the body while the plurality of legs are kept arriving at the floor, under another requirement that the first control element has determined that the correction requirement is satisfied. 
         [0014]    In accordance with the robot of the third aspect of the present invention, the position or the like of the body is corrected by controlling the movement of the leg joint mechanism group on the current spot of the robot while the robot allows each foot to keep arriving at the floor, under a requirement such that it has been determined that the “correction requirement” is satisfied. Accordingly, the position or the like of the body can be appropriately corrected from the viewpoint of executing the designated task in the second designated area with each foot being kept arriving at the floor, while avoiding such a situation that the robot becomes unstable during standing thereof. 
         [0015]    A robot of a fourth aspect of the present invention is characterized in that, with the robot of the third aspect of the present invention the second control element controls the movement of the leg joint mechanism group so as to be stopped again in the second designated area, after the robot has executed the floor-leaving and the floor-arriving of a part or all of the plurality of legs in the second designated area from a state where the robot keeps standstill thereof in the second designated area, under a requirement that the first control element determines that the second position/posture requirement and the correction element are not satisfied. 
         [0016]    In accordance with the robot of the fourth aspect of the present invention, in a case where it has been determined that the “correction requirement” is not satisfied, that is, in a case where a state where the standing of the robot may become unstable if the position or the like of the body is corrected on the current spot while the robot allows each foot to be kept arriving at the floor, the robot moves so as to perform stepping on the current spot thereof. In addition, the number of times of the floor-leaving and floor-arriving of the respective legs may be single time or multiple times, and may differ for respective legs. As a result, the position or the like of the body in the second designated area can be changed, so that the correction requirement may be satisfied. In addition, the position or the like of the body can be corrected in the second designated area with each foot being kept arriving at the floor to be appropriate from the viewpoint of executing the designated task, and avoiding a situation where the robot during standing thereof becomes unstable. 
         [0017]    A robot of a fifth aspect of the present invention is characterized in that, with the robot of the third aspect of the present invention the second control element controls the movement of the leg joint mechanism group so that, after the robot has moved from the second designated area to another area, the robot is then moved to the second designated area to come to a standstill again there, under a requirement that the first control element has determined that the second position/posture requirement and the correction element are not still satisfied. 
         [0018]    In accordance with the robot of the fifth aspect of the present invention, in a case where the “correction requirement” is not satisfied, the robot once moves from the second designated area to another area, and then moves back again to the second designated area, and comes to standstill there. As a result, the position or the like of the body in the second designated area can be changed so that the correction requirement may be satisfied. In addition, the position or the like of the body can be corrected in the second designated area with each foot being kept arriving at the floor to be appropriate from the viewpoint of executing the designated task, while avoiding a situation where the robot during standing thereof becomes unstable as mentioned above. 
         [0019]    A robot of a sixth aspect of the present invention is characterized in that, with the robot of the first aspect of the present invention the first control element determines whether or not a first position/posture requirement is satisfied that the position and posture of the body fall within a first target position range and a first target posture range, respectively, which are defined from a viewpoint such that the position and posture of the body are adjusted in advance in a first designated area so that an amount of correction of the position, posture, or the position and posture of the body in the second designated area may be reduced, in a state where the robot is in standstill in the first designated area different from the second designated area, and the second control element controls a movement of the leg joint mechanism group so that the robot comes to standstill after the robot has moved from the first designated area to the second designated area, under a requirement such that the first control element has determined that the first position/posture requirement is satisfied. 
         [0020]    In accordance with the robot of the sixth aspect of the present invention, the robot has moved to the second designated area from the first designated area, and then comes to stop there, under the requirement that the “first position/posture requirement” is satisfied. Accordingly, the position or the like of the body in the first designated area can be appropriately corrected in advance from the viewpoint that the robot reduces the amount of correction, such as the position of the body in the second designated area, and smoothly executes the designated task. 
         [0021]    A robot of a seventh aspect of the present invention is characterized in that, with the robot of the sixth aspect of the present invention the second control element controls the movement of the leg joint mechanism group so that, after the robot has executed the floor-leaving and floor-arriving of a part or all of the plurality of legs in the first designated area from a state where the robot is in standstill in the first designated area, under a requirement such that the first control element has determined that the first position/posture requirement is not still satisfied. 
         [0022]    In accordance with the robot of the seventh aspect of the present invention, in case where it has been determined that the “first position/posture requirement” is not satisfied, the robot operates so as to perform stepping on the current spot. Incidentally, the number of times of the floor-leaving and floor-arriving of the leg may be a single time or multiple times, and may differ for every leg. As a result, the robot can change the position or the like of the body in the first designated area so that the first position/posture requirement may be satisfied. Accordingly, when the robot has moved to the second designated area from the first designated area, the position or the like of the body in the first designated area can be appropriately corrected in advance from the viewpoint that the robot reduces the amount of correction, such as the position of the body in the first designated area, and smoothly executes the designated task. 
         [0023]    A robot of an eighth aspect of the present invention is characterized in that, with the robot of the first aspect of the present invention there are further provided a battery and a first connector, and that a task of connecting a second connector behaving as the target object and driven by a drive source provided for a charging installation, to the first connector, and of charging the battery by the charging installation, is executed as the designated task. 
         [0024]    In accordance with the robot of the eighth aspect of the present invention, in a case where the position or the like of the body is inappropriate notwithstanding that the robot keeps stopping in the second designated area, the designated task by which the second connector is connected to the first connector and the battery is charged by the charging installation can be executed after the robot corrected the position or the like of the body thereof on the current spot in the second designated area. 
         [0025]    A robot of a ninth aspect of the present invention is characterized in that, with the robot of the eighth aspect of the present invention a task of driving the second connector by the drive source of the charging installation in a state where the first and second connectors are connected together, thereby removing the second connector from the first connector, is executed as the designated task. 
         [0026]    In accordance with the robot of the ninth aspect of the present invention, in a case where the position or the like of the body is inappropriate notwithstanding that the robot stops in the second designated area, there is such an unfavorable possibility that the second connector is not removed from the first connector, the position or the like of the body of the robot changes with the movement of the second connector, and the standing state of the robot becomes unstable. Despite this, is should be appreciated that the robot can correct the position or the like of the body on the current spot in the second designated area as mentioned above. Accordingly, it is able to execute a designated task in which the second connector is surely removed from the first connector while avoiding an unfavorable situation such that the standing state of the robot becomes unstable because of the movement of the second connector. 
         [0027]    A robot of a tenth aspect of the present invention is characterized in that, with the robot of the first aspect of the present invention there are further provided an arm articulated to the body via a first arm joint mechanism and capable of being bent and stretched by a second arm joint mechanism, and a hand articulated to an end of the arm via a third arm joint, whereby the robot executes a task of gripping the target object by the hand as the designated task. 
         [0028]    In accordance with the robot of the tenth aspect of the present invention, in a case where the position or the like of the body is inappropriate notwithstanding that the robot stops in the second designated area, such a designated task that the arm or the like is moved, and the target object is surely gripped by the hand can be executed after the robot corrected the position or the like of the body on the current spot in the second designated area. 
         [0029]    A robot of an eleventh aspect of the present invention is characterized in that, with the robot of the tenth aspect of the present invention a task of handing the target object gripped by the hand to a human being or another robot is executed as the designated task. 
         [0030]    In accordance with the robot of the eleventh aspect of the present invention, in a case where the position or the like of the body is inappropriate notwithstanding that the robot stops in the second designated area, such a designated task that the arm or the like is moved, so that the target object gripped by the hand is handed to a human being or another robot can be executed after the robot corrected the position or the like of the body on the current spot in the second designated area. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]      FIG. 1  is a general perspective view illustrating the general construction of a robot according to the present invention; 
           [0032]      FIG. 2  is a side elevational view illustrating general constructions of both a robot according to the present invention and a charging installation for execution of a designated task; 
           [0033]      FIG. 3  is a perspective view, in part removed, illustrating the construction of a first connector; 
           [0034]      FIG. 4  is a side view illustrating the general construction of the first connector and a second connector; 
           [0035]      FIG. 5  is a perspective view illustrating the construction of the charging installation; 
           [0036]      FIG. 6  is a schematic block diagram illustrating the construction of a controller of the robot according to the present invention; 
           [0037]      FIG. 7  is a flow chart illustrating a position and posture control method by the robot according to the present invention; 
           [0038]      FIG. 8  is a flow chart illustrating a method for executing a first designated task and a second designated task; 
           [0039]      FIGS. 9(   a ) through  9 ( c ) are schematic views illustrating the operations performed by the robot according to the invention; 
           [0040]      FIGS. 10(   a ) through  10 ( c ) are schematic outside views illustrating a body position correction of the robot according to the present invention; 
           [0041]      FIGS. 11(   a ) through  10 ( c ) are schematic outside views illustrating a body posture correction of the robot according to the present invention; 
           [0042]      FIGS. 12(   a ) and  12 ( b ) are schematic outside views illustrating a disturbance on the body position/posture of the robot according to the present invention; and 
           [0043]      FIGS. 13(   a ) through  13 ( c ) are explanatory views illustrating diverse designated tasks to be executed by the robot according to the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0044]    An embodiment of a robot of the present invention will be described hereinbelow with reference to the accompanying drawings. First of all, the general construction of the robot will be described. 
         [0045]    A robot  1  shown in  FIG. 1  is a legged type mobile robot, and like a human being, includes a body  10 , a head  11  arranged above the body  10 , right and left arms  12  provided at an upper portion of the body  10  to extend from both upper sides, hands  13  provided respectively at the tips of the right and left arms  12 , and right and left legs  14  provided to extend downward from a lower portion of the body  10 . The robot  1  has a controller  100  which controls the operation thereof, and a battery  1100 . 
         [0046]    The body  10  is constituted by an upper portion and a lower portion which are mutually interconnected up and down so as to relatively rotate about a yaw axis. The head  11  can be moved to conduct a rotation about the yaw axis and so on with respect to the body  10 . The head  11  is loaded with a pair of right and left head cameras C 1  which can sense light in various frequency bands, such as a CCD camera or an infrared camera which has the front of the robot  1  as an imaging range. A lower portion of the body  10  is loaded with a waist camera (active sensor) C 2  for detecting reflected light of a near-infrared laser beam from an article when the laser beam is emitted towards the lower front of the robot  1 , to measure the position, orientation and the like of the article. 
         [0047]    Each arm  12  includes a first arm link  122  and a second arm link  124 . The body  10  and the first arm link  121  are movably connected together via a shoulder joint mechanism (a first arm joint mechanism)  121 , the first arm link  122  and the second arm link  124  are movably connected to one another via an elbow joint mechanism (a second arm joint mechanism)  123 , and the second arm link  124  and the hand  13  are movably connected together via a carpal joint mechanism (a third arm joint mechanism)  125 . The shoulder joint mechanism  121  has rotational degrees of freedom about roll, pitch, and yaw axes, the elbow joint mechanism  123  has a rotational degree of freedom about the pitch axis, and the carpus joint mechanism  125  has rotational degrees of freedom about the roll, pitch, and yaw axes. 
         [0048]    The hand  13  includes five finger mechanisms  131  to  135  which extend from a palm, and correspond to the thumb, forefinger, middle finger, ring finger, and a little finger, respectively, of a human being&#39;s hand. The first finger mechanism  131  and the four finger mechanisms  132  to  135  which are laterally arrayed are disposed to oppose to one another. The first finger mechanism  131  includes three link members respectively corresponding to a first metacarpal bone, and a proximal phalanx and a distal phalanx of the thumb in the human being&#39;s hand, and an elastic cover which covers the three link members. The three link members are connected together via joints respectively corresponding to a joint on the side of a base part of the first metacarpal bone and a metacarpophalangeal joint and an interphalangeal joint of the thumb, in the human being&#39;s hand sequentially from the palm. The first finger mechanism  131  can be bent in each joint according to a force transmitted from a motor housed in the palm via a power transmission mechanism constituted by a speed reduction mechanism, etc. The power transmitted to the first finger mechanism  131  from the motor is controlled by a controller  100 . The finger mechanisms  132  to  135  are adapted to have an identical construction to the finger mechanisms disclosed, for example, in Japanese Patent Application Laid-Open No. 2003-181787, and are adapted to have almost the same construction as each other. For example, the fifth finger mechanism  135  includes three link members respectively corresponding to a proximal phalanx, a middle phalanx and a distal phalanx of the little finger of the human being&#39;s hand, and an elastic cover which covers the three link members. The three link members are connected together via joints respectively corresponding to a metacarpophalangeal joint, a proximal interphalangeal joint, and a distal interphalangeal joint of the little finger of the human being&#39;s hand sequentially from the palm. The fifth finger mechanism  135  can be bent inward in each joint according to the power transmitted from a motor (not shown) serving as a power source via a power transmission mechanism. The power transmitted to the fifth finger mechanism  135  from the motor is controlled by a controller  100  similarly to the first finger mechanism  131 . Additionally, the power transmission mechanism may be constituted by a wire, a pulley and so on, as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 2003-181787, and all constructions that can transmit the power of a motor so as to bend and stretch each finger mechanism may be adopted. 
         [0049]    Each leg  14  includes a first leg link  142 , a second leg link  144 , and a foot  15 . The body  10  and the first leg link  142  are connected together via a hip joint mechanism (a first leg joint mechanism)  141 , the first leg link  142  and the second leg link  144  are connected together via a knee joint mechanism (a second leg joint mechanism)  143 , and the second leg link  144  and the foot  15  are movably connected together via a foot joint mechanism (a third leg joint mechanism)  145 . The hip joint mechanism  141  has rotational degrees of freedom about roll, pitch, and roll axes, the knee joint mechanism  143  has rotational degrees of freedom about the pitch axis, and the foot joint mechanism  145  has rotational degrees of freedom about roll and pitch axes. The hip joint mechanism  141 , the knee joint mechanism  143 , and the foot joint mechanism  145  constitute a “leg joint mechanism group.” In addition, translational and rotational degrees of freedom of each joint mechanism included in the leg joint mechanism group may be changed suitably. Additionally, after one arbitrary joint mechanism of the hip joint mechanism  141 , the knee joint mechanism  143 , and the foot joint mechanism  145  is omitted, the leg joint mechanism group may be constructed by combinations of the two remaining joint mechanisms. Moreover, in a case where the leg  14  has a second leg joint mechanism separate from a knee joint, the leg joint mechanism group may be constructed so as to include the second leg joint mechanism. In order to relax the impact at the time of foot landing, the sole of the foot  15  is provided with an elastic material  152  as disclosed in Japanese Patent Application Laid-Open No. 2001-129774. 
         [0050]    As shown in  FIG. 2 , a first connector  1200  for charging the battery  1100  is provided on the back side of the body  10 . As shown in  FIGS. 3 and 4 , first charging terminals  1220 , terminals  1240  for a first signal, and tubes  1260  are provided in parallel in the first connector  1200 . A side wall of each tube  1260  is partially cut out, thereby forming guides  1270 . 
         [0051]    The robot  1  executes tasks, such as charging the battery  1100  by a charging installation  2  shown in  FIG. 2 . The charging installation  2  includes a power source  2100  for charging, a charge controller  200  which controls the operation of the charging installation  2 , a second connector  2200 , and a connector drive mechanism  2300 . Additionally, the charging installation  2  includes a first sensor  211  which detects a first mark M 1  provided at a heel of the robot  1 , using light, such as infrared light, and a second sensor  212  which detects a second mark M 2  provided at the back of the body  10  of the robot  1 , using light, such as infrared light. 
         [0052]    As shown in  FIGS. 4 and 5 , second charging terminals  2220 , terminals  2240  for a first signal, and rods  2260  are provided in parallel in the second connector  2200  so as to protrude in a horizontal direction. A pair of pins  2270  is provided so as to protrude from side walls of each rod  2260 . The rod  2260  is attached to the second connector  2200  in a state wherein its radial movement or wobbling is possible by a compliance mechanism. 
         [0053]    The connector drive mechanism  2300  is a cylinder-type drive mechanism. As shown in  FIG. 5 , the connector drive mechanism  2300  includes a foundation  230 , a slider  2310  which has the second connector  2200  attached to a distal end thereof, a cylinder rod  2320  which makes the slider  2310  slide and reciprocate on the foundation  230 , a compliance mechanism  2340  which holds the cylinder rod  2320  in a state where its radial movement or wobbling is possible, and a rod rotation driving mechanism  2360  which rotates the rod  2260  about an axis. The position of the second connector  2200  is measured on the basis of the amount of driving of the slider  2310  by the cylinder rod  2320 . In addition, the second connector  2200  may be driven to advance or retreat in all the directions that the force of a horizontal component acts on the robot  1  at the time of retreat driving in addition to the horizontal direction. 
         [0054]    In a state where the first connector  1200  and the second connector  2200  are connected together, the first charging terminals  1220  and the second charging terminals  2220  are connected, the terminals  1240  for a first signal and the terminals  2240  for a second signal are connected, and the rods  2260  are inserted into tubes  1260 , and the pins  2270  are engaged with terminal ends of the guides  1270 . On the other hand, in a state where the second connector  2200  is disconnected from the first connector  1200 , the first charging terminals  1220  and the second charging terminals  2220  are separated from each other, the terminals  1240  for a first signal and the terminals  2240  for a second signal are separated from each other, the pins  2270  is released from the engagement with the terminal ends of the guides  1270 , and the rods  2260  are pulled out of the tubes  1260 , respectively. 
         [0055]    The controller  100  shown in  FIG. 6  is constituted by a CPU, a ROM, a RAM, an I/O, etc., and controls the operation of an actuator  1000  according to an action plan stored in a memory unit, on the basis of an output signal from each of sensors which constitute a sensor group  102 , thereby controlling the action of the robot  1 . The “action plan” is defined by a “target posture orbit” etc. showing a time-series changing mode of the target position of the robot  1 , and a “target position track” showing a time-series changing mode of the target posture of the robot  1 . In addition to the head camera C 1  and the waist camera C 2 , an inclination angle sensor which outputs a signal according to the inclination angle or posture of the body  10  with respect to a horizontal plane, a yaw rate sensor which outputs a signal according to the angular velocity the robot  1  about the yaw axis, an acceleration sensor which outputs a signal according to the acceleration of the robot  1  in the directions of the roll axis, the pitch axis, etc., and a rotary encoder which outputs a signal according to the angle of each joint, etc. are included in the sensor group  102 . The position of an origin of a robot coordinate system (X R , Y R , Z R ) shown in  FIG. 1  in a fixed coordinate system or a global coordinate system (X, Y, Z), or a translation matrix or quaternion showing translation to the position in the fixed coordinate system is measured as the position of the body  10  on the basis of the output of the sensors which constitute the sensor group  102 . Additionally, the azimuth angle and elevation angle of a robot coordinate system in the fixed coordinate system in an +Z R  direction, or a rotation matrix or quaternion showing the rotation by the azimuth angle and elevation angle in the fixed coordinate system are measured as the posture of the body  10 . 
         [0056]    The controller  100  includes a first control element  110  which determines whether or not requirements to be described later are satisfied, and a second control element  120  which controls the operation of the robot  1  as described above according to the determined result by the first control element  110 . In addition, the controller  100  may be a distributed controller constituted by a main control unit or a plurality of subcontrol units which are connected through an internal network of the robot  1 . 
         [0057]    The functions of the robot  1  with the above construction will now be described. The outline of the functions of the robot  1  will be first described. First of all, as shown in  FIG. 9A , the robot  1  moves toward a first designated area ahead of the charging installation  2 . Further, as shown in  FIG. 9B , the robot  1  turns its back to the charging installation  2  and stops in the first designated area. Moreover, as shown in  FIG. 9C , the robot  1  stops in a second designated area after having moved backward from the first designated area. Then, the robot  1  stops in the second designated area, and executes a “first designated task” and a “second designated task” in order. The “first designated task” is a task of charging the battery  1100  by the charging installation  2  after the second connector  2200  has been connected to the first connector  1200 . The “second designated task” is a task of removing the second connector  2200  from the first connector  1200 . 
         [0058]    A series of operation functions of the robot  1  will be described in detail. First, when the robot  1  moves toward the first designated area, one or both positions and postures of the floor marks FM 1  and FM 2  are measured on the basis of, for example, an image around imaged by the waist camera C 2 , and the action plan is generated on the basis of the measurement results. Then, the operation of the robot  1  including the movement of the leg joint mechanism group is controlled such that the robot  1  moves toward the first designated area as shown in  FIG. 9A , and turns its back to the charging installation  2  and stops in the first designated area as shown in  FIG. 9B , according to this action plan (FIG.  7 /S 102 ). When the robot  1  has stopped, the movement of all the leg joint mechanisms included in the leg joint mechanism group is stopped, while electric power is supplied to the actuator  1000  so that a state where the legs  14  are bent lightly and stand in the knee joint mechanism  143  as shown in  FIG. 2  may be maintained. 
         [0059]    The first control element  110  determines whether or not a “first position/posture requirement” is satisfied, in a state where the robot  1  has stopped in the first designated area (FIG.  7 /S 104 ). The “first position/posture requirement” is a requirement that the position and posture of the body  10  fall within a “first target position range” and a “first target posture range,” respectively. The “first target position range” and the “first target posture range” are defined from a viewpoint that the position and posture of the body  10  are adjusted in advance in the first designated area so that the amount of correction of the position or the like of the body  10  in the second designated area may be reduced, and are stored in the memory unit. At this time, the position and posture of the body  1  relative to the first floor mark FM 1  are measured as the position and posture of the body  1 . The position and posture of the body  1  relative to the first floor mark FM 1  can be measured on the basis of such a measurement result that is obtained by firstly measuring the position and posture of the first floor mark FM 1  with respect to the waist camera C 2  through the waist camera C 2 , and the position, posture, etc. of the waist camera C 2  (or light-receiving element of the waist camera C 2 ) in the robot coordinate system that were stored in advance in the memory unit. In addition, the position and posture of the body  10  may be measured on the basis of an output signal from the rotary encoder showing the angle of each joint mechanism, and the output from other sensors, such as a value measured according to an inverse-dynamic or geometric computation model on the basis of the length or the like of each link stored in advance in the memory unit. Additionally, whether or not the first position/posture requirement is satisfied may be determined according to whether or not the position and posture of the first floor mark FM 1  which are measured through the waist camera C 2  in a state where the robot  1  has stopped in the first area coincide with the target position and target posture, respectively, of the first floor mark FM 1  stored in the memory unit, or are in a predetermined error range. 
         [0060]    If the first control element  110  determines that the first position/posture requirement is satisfied (FIG.  7 /NO in S 104 ), the movement of the leg joint mechanism group is controlled so as to be stopped again in the first designated area, after the robot  1  performs floor-leaving and floor-arriving of a part or all of the plurality of legs  14  in the first designated area (FIG.  7 /S 108 ). Hence, the position or the like of the body can be corrected while the robot  1  performs stepping on the spot. 
         [0061]    On the other hand, if the first control element  110  determines that the first position/posture requirement is satisfied (FIG.  7 /YES in S 104 ), the second processing element  120  controls the movement or the like of the leg joint mechanism group so that the robot  1  may move backward to the second designated area from the first designated area as shown to  FIG. 9C , and stop in the second designated area (FIG.  7 /S 106 ). 
         [0062]    The first control element  110  determines whether or not a “second position/posture requirement” is satisfied, in a state where the robot  1  keeps stopping in the second designated area (FIG.  7 /YES in S 110 ). The “second position/posture requirement” is a requirement that the position and posture of the body  10  fall within a “second target position range” and a “second target posture range,” respectively. The “second target position range” and the “second target posture range” are defined from a viewpoint that the robot  1  is made to reliably execute a designated task. At this time, the position and posture of the body  10  relative to the second floor mark FM 2  are measured as the position and posture of the body  10 . The position and posture of the body  10  relative to the second floor mark FM 2  can be measured on the basis of such a measurement result that is obtained by firstly measuring the position and posture of the second floor mark FM 2  with respect to the waist camera C 2  through the waist camera C 2 , and the position, posture, etc. of the waist camera C 2  in the robot coordinate system that were stored in advance in the memory unit. In addition, the position and posture of the body  10  may be measured on the basis of an output signal from the rotary encoder showing the angle of each joint mechanism, and the output from other sensors, such as a value measured according to an inverse-dynamic or geometric computation model on the basis of the length or the like of each link stored in advance in the memory unit. Additionally, whether or not the second position/posture requirement is satisfied may be determined according to whether or not the position and posture of the first floor mark FM 1  which are measured through the waist camera C 2  in a state where the robot  1  has stopped in the first area coincide with the target position and target posture, respectively, of the second floor mark FM 2  stored in the memory unit, or are in a predetermined error range. 
         [0063]    If the first control element  110  determines that the second position/posture requirement is not satisfied (FIG.  7 /NO in S 110 ), the first control element further determines whether or not a “correction requirement” is satisfied  110  (FIG.  7 /S 114 ). The “correction requirement” is a requirement that the second position/posture requirement is satisfied by adjusting the movement of the leg joint mechanism group on the spot while the robot  1  allows the plurality of legs  14  or feet  15  to arrive at a floor, thereby performing correction so that the position and posture of the body  10  may not exceed a “variable position range” and a “variable posture range,” respectively. The “variable position range” and the “variable posture range” are defined from a viewpoint that the robot  1  stably maintains its standing state, such that the position of ZMP falls within an allowable range so as not to deviate therefrom. 
         [0064]    If the first control element  110  determines that the correction requirement is satisfied (FIG.  7 /YES in S 114 ), the second control element  120  controls the movement of the leg joint mechanism group so that, while the robot  1  allows the plurality of feet  15  to arrive at a floor, the position or the like of the body  10  may be changed on the spot (FIG.  7 /S 116 ). At this time, an action plan including a target joint angle orbit showing a time-series changing mode of a target joint angle about each axis of each joint mechanism is generated, and the movement of each joint mechanism is controlled so that a joint angle orbit may follow this target angle orbit. As a result, as shown in  FIGS. 10A  to  10 C, respectively, the position of the body  10  can be shifted as indicated by arrows in a direction of an X R  axis (roll axis), in a direction of a Y R  axis (pitch axis), and in a direction of a Z R  axis (yaw axis) in a state the foot  15  arrives at the floor. Additionally, as shown in  FIGS. 11A to 11C , respectively, the posture of the body  10  can be corrected by the rotations as indicated by arrows around the directions of the roll axis, the pitch axis, and the yaw axis in a state the foot  15  is brought to arriving at the floor. 
         [0065]    On the other hand, if the first control element  110  has determined that the correction requirement is not satisfied by (FIG.  7 /NO in S 114 ), the second control element  120  controls the movement or the like of the leg joint mechanism group so that the robot  1  may move to the first designated area where the position or the like thereof is suitably corrected, then move to the second designated area, and then stop again in the second designated area (refer to FIG.  7 /S 102 , S 106 , S 108 , etc.). In addition, after the robot  1  has moved to an area different from the second designated area, the movement or the like of the leg joint mechanism group may be controlled so that the robot may return to and then stop in the second designated area. 
         [0066]    Then, if the first control element  110  determines that the second position/posture requirement is satisfied (FIG.  7 /YES in S 110 ), the second control element  120  determines whether or not execution of a designated task is completed (FIG.  7 /S 112 ). If it has been determined that the execution of the designated task is not completed (FIG.  7 /NO in S 112 ), the controller  100  controls the operation of the robot  1  so that the execution of the designated task may be started or continued (FIG.  7 /S 118 ). The first control element  110  determines whether or not the “second position/posture requirement” is satisfied, even during the execution of the designated task by the robot  1  (FIG.  7 /S 120 ). In addition, while the robot  1  is executing the designated task, whether or not a requirement that the posture of the body  10  falls within the second target posture range or a requirement that the position of the body  10  falls within the second target position range is satisfied instead of the second position/posture requirement may be determined. Then, if the first control element  110  determines that the second position/posture requirement is not satisfied (FIG.  7 /NO in S 120 ), the position or the like of the body  10  etc. is corrected as the second control element  120  controls the movement of the leg joint mechanism group while the robot  1  has allowed the foot  15  to arrive at a floor (FIG.  7 /S 122 ). Then, the second control element  120  determines whether or not the execution of a designated task is completed (FIG.  7 /S 112 ). If the second control element  110  determines that the second position/posture requirement is satisfied (FIG.  7 /YES in S 120 ), the second control element  120  determines whether or not the execution of the designated task is completed (FIG.  7 /S 112 ). If it has been determined that the execution of the designated task is completed (FIG.  7 /YES in S 112 ), a series of processing mentioned above is completed. 
         [0067]    Here, an execution method of a designated task by the robot  1  will be described. It is determined in the charging installation  2  whether or the like the first mark M 1  given to the heel (rear side of the foot  15 ) of the robot  1  which has stopped in the second designated area has been detected by the first sensor  211  (FIG.  8 /YES in S 202 ). Then, under a requirement that the second mark M 2  given to the back of the body  10  of the robot  1  has been detected by the second sensor  212  (FIG.  8 /YES in S 204 ), the connector drive mechanism  2300  drives the second connector  2200  forward or drives the second connector in a direction in which the second connector approaches the first connector  1200  (FIG.  8 /S 206 ). 
         [0068]    Thereafter, under a requirement that the second connector  2200  has reached a connected position in a given amount of time (FIG.  8 /YES in S 208 ), connector locking is executed (FIG.  8 /S 210 ). When the second connector  2200  is in the connected position, the distal ends of the rods  2260  are inserted into the tubes  1260 , and the pins  2270  are guided to the distal ends of the guides  1270 . The connector locking is executed as the rods  2260  is rotationally driven in a given direction about an axis by the rod rotation driving mechanism  2360 . At this time, the second connector  2200  is driven forward so as to assist in realization of the connector locking. As a result, while the pins  2270  provided so as to protrude from the side walls of the rods  2260  are guided by the guides  1270  of the tubes  1260 , the rods  2260  are gradually inserted into the tubes  1260 , and the pins  2270  are engaged with the terminal ends of the guides  1270 , thereby realizing the connector locking. The second connector  2200  and the first connector  1200  are brought into a connected state by the realization of the connector locking. That is, the second charging terminals  2220  and the first charging terminals  1220  are connected together, and the terminals  2240  for a second signal and the terminals  1240  for a first signal are connected together. 
         [0069]    Further, if it has been determined that the connector locking has completed on the basis of the angle of rotation of the rods  2260  by the rod rotation driving mechanism  2360  (FIG.  8 /YES in S 212 ), the forward driving of the second connector  2200  is stopped (FIG.  8 /S 214 ). Further, the charge controller  200  communicates with the controller  100  via the terminals  1240  for a first signal and the terminals  2240  for a second signal, thereby supplying a charging current to the battery  1100  via the first charging terminals  1220  and the second charging terminals  2220  from the power source  2100  for charging, recognizing the residual capacity or the like of the battery  1100  (FIG.  8 /S 216 ). Then, under a requirement that the charge controller  200  has determined on the basis of an output signal from the controller  100  that the charging of the battery  1100  has been completed (FIG.  8 /YES in S 218 ), the supply of an electric current to the battery  1100  from the power source  2100  for charging is stopped (FIG.  8 /S 220 ). In this step, the robot  1  executes the “first designated task” that the battery  1100  is charged by the charging installation  2  after having connected the second connector  2200  to the first connector  1200 . 
         [0070]    Subsequently, connector unlocking is executed (FIG.  8 /S 222 ). At this time, the rods  2260  are rotationally driven about an axis in a direction opposite to a direction at the time of connector locking driving by the rod rotation driving mechanism  2360 . Further, the second connector  2200  may be driven backward so as to assist in realization of the connector unlocking. As a result, while the pins  2270  provided so as to protrude from the side walls of the rods  2260  are guided by the guides  1270  of the tubes  1260 , the rods  2260  are pulled out of the tubes  1260 , thereby realizing the connector unlocking. By the realization of the connector unlocking, the first charging terminals  1220  and the second charging terminals  2220  are separated from each other, and the terminals  1240  for a first signal and the terminals  2240  for a second signal are separated from each other, whereby the second connector  2200  is removed from he first connector  1200 . 
         [0071]    Further, under a requirement that it has been determined on the basis of the angle of rotation of the rod  2260  by the rod rotation driving mechanism  2360  that the connector unlocking have been realized (FIG.  8 /YES in S 224 ), the second connector  2200  is driven backward by the connector drive mechanism  2300  (FIG.  8 /S 226 ). Then, under a requirement that it have been determined that the second connector  2200  has returned to its initial position (FIG.  8 /YES in S 228 ), the backward driving of the second connector  2200  is stopped (FIG.  8 /S 230 ). In this step, the robot  1  executes the “second designated task” that the second connector  2200  is removed from the first connector  1200 . 
         [0072]    According to the robot  1  which exhibits the above functions, while the robot  1  had allowed each foot  15  to arrive at a floor, the movement of the leg joint mechanism group is controlled on the spot under a requirement the “second position/posture requirement” is satisfied in a state where the robot has stopped in the second designated area. Thereby, the position or the like of the body  10  can be adjusted (refer to FIG.  7 /YES in S 110 ,  116 ,  FIG. 10 , and  FIG. 11 ). Accordingly, in a case where the position or the like of the body  10  is unsuitable from a viewpoint that the robot  1  execute designated tasks, such as the first designated task and the second designated task, the robot  1  can execute the designated tasks after the position or the like of the body  10  is suitably executed on the spot in the second designated area (refer to FIG.  7 /S 118 ). In addition, factors that the second position/posture requirement is no longer satisfied when the robot has stopped in the second designated area include some asymmetry properties of operating characteristics of the robot  1 , such as the inclination angle or existence of irregularities, of a floor where the robot  1  is standing, the inclination angle of a floor while the robot  1  is moving to the second designated area from the first designated area, the variation of a coefficient of friction, and the elastic property of the elastic material  152  of the right and left feet  15  of the robot  1 . 
         [0073]    Additionally, the position or the like of the body  10  can be suitably corrected in the second designated area by controlling the movement of the leg joint mechanism group in a state where the robot allowed each foot  15  to arrive at a floor so that the second position/posture requirement may be satisfied even while the robot  1  executes the designated task (refer to FIG.  7 /S 120 , and S 122 ). Accordingly, the position or the like of the body  10  can be corrected and a designated task can be continued and executed, as mentioned above, even in a case where the second position/posture requirement is no longer satisfied due to any disturbance generated after the start of execution of the designated task. 
         [0074]    For example, as shown in  FIG. 12A , a situation where the robot  1  is pushed forward toward the second connector  2200  and its posture is collapsed a little is considered for the reasons that the rods  2260  are exactly inserted into the tubes  1260  while the robot  1  executes the first designated task. In this situation, the robot  1  can modify the position or the like of the body  10  by moving some or all of the leg joint mechanism group delicately while the robot allowed each foot  15  to arrive at a floor in the second designated area (refer to  FIGS. 10 and 11 ). Also, the first designated task that the second connector  2200  is connected to the first connector  1200  and the battery  1100  is charged by the charging installation  2  can be executed. 
         [0075]    Additionally, as shown in  FIG. 12B , a situation where the robot  1  is pulled backward toward the second connector  2200  and its posture is collapsed a little is considered for the reasons that the rods  2260  are caught on the tubes  1260  although the connector locking has succeeded while the robot  1  executes the second designated task. In this situation, the robot  1  can modify the position or the like of the body  10  by moving some or all of the leg joint mechanism group delicately while the robot allowed each foot  15  to arrive at a floor in the second designated area (refer to  FIGS. 10 and 11 ). Also, the second designated task that the second connector  2200  is removed from the first connector  1200  can be executed by making the charging installation  2  drive the second connector  2200 . Moreover, the position or the like of the body  10  is corrected by controlling the movement of the leg joint mechanism group on the spot while the robot  1  allowed each foot to arrive at a floor, under a requirement that it has been determined that the “correction requirement” is satisfied in addition to the second position/posture requirement (refer to FIG.  7 /YES in S 114 , and S 116 ). Accordingly, the position or the like of the body  10  can be appropriately corrected from the viewpoint of execution of a designated task in the second designated area with each foot  15  arriving at the floor while avoiding a situation where a standing state of the robot  1  becomes unstable. 
         [0076]    Additionally, in a case where it has been determined that the “correction requirement” is not satisfied, that is, in a case where a state where the robot  1  is standing may become unstable if the position or the like of the body  10  is corrected on the spot while the robot  1  allowed each foot  15  to arrive at a floor, the robot  1  once moves to the first designated area (other areas) from the second designated area, and corrects the position or the like of the body  10 . Then, the robot  1  moves to the second designated area again, and stops there (refer to FIG.  7 /NO in S 114 , S 104 , S 106 , S 108 , and  FIGS. 9B and 9C ). As a result, the position or the like of the body  10  in the second designated area can be changed so that the correction requirement may be satisfied. In addition, the position or the like of the body  10  can be suitably corrected from the viewpoint of execution of a designated task in the second designated area, avoiding a situation where a state where the robot is standing becomes unstable, while the robot  1  allowed each foot  15  to arrive at a floor (refer to FIG.  7 /YES in S 114 , and S 116 ). In addition, in a case where it has been determined that the “correction requirement” is not satisfied in a state where the robot  1  has stopped in the second designated area, the operation of the robot  1  may be controlled so that the robot may perform stepping in the second designated area. Even in this case, the position or the like of the body  10  in the second designated area can be changed so that the correction requirement may be satisfied. 
         [0077]    Moreover, the robot  1  has moved to the second designated area from the first designated area, and then stops there, under a requirement that the “first position/posture requirement” is satisfied (FIG.  7 /YES in S 104 , and S 106 ). Accordingly, the position or the like of the body  10  in the first designated area can be suitably corrected in advance from a viewpoint that the robot  1  reduces the amount of correction, such as the position of the body  10  in the second designated area, and smoothly executes a designated task. 
         [0078]    Additionally, if it has been determined that the “first position/posture requirement” is not satisfied, the robot  1  operates so as to perform stepping on the spot (refer to FIG.  7 /NO in S 104 , and S 108 ). As a result, the robot  1  can change the position or the like of the body  10  in the first designated area so that the first position/posture requirement may be satisfied. Accordingly, when the robot  1  has moved to the second designated area from the first designated area, the position or the like of the body  10  in the first designated area can be suitably corrected in advance from a viewpoint that the robot reduces the amount of correction, such as the position of the body  10  in the first designated area, and smoothly executes a designated task. 
         [0079]    In addition, the robot  1  may execute various designated tasks different from the first designated task and the second designated task. In order to execute any kind of designated task, as mentioned above, the robot  1  can execute the designated task after the position or the like of the body  10  is suitably modified, while the robot allowed each foot  15  to arrive at a floor in the second designated area. 
         [0080]    For example, as shown in  FIG. 13A , as the robot  1  moves the arms  12  or the like in a state where the robot has stopped in the second designated area, the robot may execute a designated task of gripping a tray (target object) W 1  with the hands  13 . The robot  1  determines whether or not the second position/posture requirement is satisfied according to whether or not the position and posture of the tray W 1  coincide with a reference position and a reference posture stored in the memory unit, after the robot has recognized the position and posture of the tray W 1  on the basis of an image of the tray W 1  obtained through the head camera C 1 . Additionally, as shown in  FIG. 13B , as the robot  1  moves the arms  12  or the like in a state where the robot has stopped in the second designated area, the robot may execute a designated task of gripping a handle (target object) H or the like of a carriage W 2 . The robot  1  determines whether or not the second position/posture requirement is satisfied according to whether or not the position and posture of the carriage W 2  coincide with a reference position and a reference posture stored in the memory unit, after the robot has recognized the position and posture of the carriage W 2  on the basis of an image given to the lower side of the carriage W 2  obtained through the waist camera C 2 . In this case, a situation where the position or the like of a target object has deviated slightly from its original position at a stage where the robot stopped in the second designated area, or where the position or the like of the target object has deviated slightly from its original position due to the fact that the hands  13  have contacted the target object during execution of a designated task, is assumed. However, even under this situation, as mentioned above, the robot  1  can execute the designated task after the position or the like of the body  10  with respect to the target object is suitably modified, while the robot allowed each foot  15  to arrive at a floor in the second designated area. 
         [0081]    Additionally, as shown in  FIG. 13C , as the robot  1  moves the arms  12  or the like in a state where the robot has stopped in the second designated area, the robot may execute a designated task of handing a target object, such as the tray W 1  gripped by the hands  13 , to a human being or the other robot  1 . The robot  1  determines whether or not the second position/posture requirement is satisfied according to whether or not the position and posture of the tray W 1  coincide with a reference position and a reference posture stored in the memory unit, after the robot has recognized the position and posture of the floor mark FM on the basis of an image of the floor mark FM obtained through the waist camera C 2 . However, a situation where the position or the like of a human being or the other robot  1  has deviated slightly from its original position at a stage where the robot has stopped in the second designated area, or where the position or the like of the body  10  has changed slightly due to the fact that the human being or the other robot  1  pulls the target object in a state where the robot  1  grips the target object with the hands  13 , is assumed. However, even under this situation, as mentioned above, the robot  1  can execute the designated task after the position or the like of the body  10  with respect to the human being or the other robot  1  is suitably modified, while the robot allowed each foot  15  to arrive at a floor in the second designated area.