Patent Publication Number: US-2015081096-A1

Title: Robot and robot system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of International Application No. PCT/JP2012/062949, filed on May 21, 2012, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD 
     A disclosed embodiment relates to a robot and a robot system. 
     BACKGROUND 
     Japanese Patent Application Laid-open No. 2008-302496 discloses a robot controller configured to control operation of the arms to coexist with humans, without damaging humans even if the arms or the like contact the humans. 
     SUMMARY 
     According to an aspect of an embodiment, a robot includes: a base to be fixed to an installation surface; and an arm unit having a plurality of arm bodies sequentially and revolvably coupled with each other with one end coupled to the base through a joint unit, wherein the arm unit includes a stopper mechanism having a movable stopper member being capable of restricting a revolving motion of the arm bodies to a predetermined revolving range. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG. 1  is an explanatory drawing illustrating a work area in which a robot system according to an embodiment is installed. 
         FIG. 2  is an explanatory drawing illustrating a turning area of an arm unit of a robot in the robot system according to the embodiment. 
         FIG. 3  is an explanatory drawing illustrating a side view of a stopper mechanism. 
         FIG. 4  is an explanatory drawing illustrating a plane view of the stopper mechanism. 
         FIG. 5  is an explanatory drawing illustrating an example of control of the stopper mechanism by a controller. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment of a robot and a robot system disclosed in the present application is described in detail with reference to the attached drawings. Note that the present invention is not to be limited by the embodiment described below. 
       FIG. 1  is an explanatory drawing illustrating a work area  100  in which a robot system  10  having a robot  1  according to the embodiment is installed, and  FIG. 2  is an explanatory drawing illustrating a turning area of an arm unit  4  of the robot  1  in the robot system  10 . 
     The robot system  10  according to the embodiment is provided with the robot  1 . As illustrated in  FIG. 1 , the robot system  10  is installed by setting up the robot  1  in a predetermined position on a floor  200  in a predetermined work area  100  of which a moving body such as an operator  6  can go in and out. Note that a position to set up the robot  1  may be set as appropriate depending on work. Here, the robot  1  is set up at a substantially central position of the work area  100 . The work area  100 , may be partitioned into a working booth (not illustrated) in a production line in a factory and the like. 
     As illustrated in  FIG. 2 , the robot system  10  is provided with a controller  5  configured to control operation of the robot  1 . In this controller  5 , control command contents for the robot  1  is stored in advance, and the robot  1  is controlled based on the stored contents. Note that the controller  5  is described in detail below. 
     As illustrated in  FIG. 1 , the robot  1  is provided with a base  2  installed on the floor  200 , and the arm unit  4  turnably provided on the base  2 . 
     The arm unit  4  is provided with an arm base body  3 , a first arm body  41 , a second arm body  42 , and a wrist unit  43  constituted of a first wrist  431 , a second wrist  432 , and a third wrist  433 , each sequentially coupled to the base  2  through a shaft. Then, an end effector (not illustrated), which is suitable for the work given to the robot  1 , is attached to a tip of the third wrist  433 . A maximum turning locus  900  illustrated in  FIG. 2  is a turning locus of the robot  1  when the arm unit  4  is extended to the maximum. 
     Thus, the robot  1  according to this embodiment is constituted of an articulated robot having the arm base body  3 , the first arm body  41 , the second arm body  42 , and the wrist unit  43 , which are movable parts. 
     As described below, the robot  1  is the articulated robot provided with a first joint unit  21  to a sixth joint unit  26 , and the movable parts thereof are revolvable around an axis. 
     The arm base body  3  also serves as a body portion of the robot  1 , and it is revolvably coupled to the substantially cylindrical base  2  installed on the floor  200  in a fixed state through the first joint unit  21 . The first joint unit  21  is provided at a substantially center of the base  2 , and is provided with a first shaft  11  extending in a vertical direction (Z direction). 
     Then, the first shaft  11  is interlocked and coupled to a first transmission mechanism provided with a first motor and a first reducer. Accordingly, the arm base body  3  is revolved horizontally to the base  2 , which is fixed to the floor  200 , around the first shaft  11  by the first transmission mechanism (see an arrow  300 ). 
     As illustrated, an upper surface of the base  2  and a lower surface of the arm base body  3  are each provided with a projected body (a first projected body  81  and a second projected body  82 ), which is positioned so as to be on a virtual circumference centering on the first shaft  11  and constitutes a stopper mechanism  8 . A specific configuration and the like of the stopper mechanism  8  are described below. 
     As described above, the second joint unit  22  is provided to one side portion of the arm base body  3 , and the first arm body  41  is revolvably coupled through the second joint unit  22 . Note that since the first arm body  41  is coupled to a position eccentric to the first shaft  11 , the second arm body  42  and the wrist unit  43 , which include the first arm body  41  and are sequentially coupled to the first arm body  41  through the shaft, are also turned centering on the first shaft  11 . 
     The second joint unit  22  is provided with a second shaft  12  extending in an orthogonal direction to the first shaft  11 , or a front and back horizontal direction (Y direction) in the drawing. Then, the second shaft  12  is interlocked and coupled to a second transmission mechanism (not illustrated) provided with a second motor and a second reducer. Accordingly, the first arm  41  is revolved around the second shaft  12 , or is swung in a vertical direction, by the second transmission mechanism (see an arrow  400 ). 
     The third joint unit  23  is provided on a tip side of the first arm body  41 , which is the longest among the movable parts. The substantially L-shaped second arm body  42  is coupled through the third joint unit  23 . 
     The third joint unit  23  is provided with a third shaft  13  extending in a parallel direction to the second shaft  12 , or extending in the same direction as the second shaft  12  being orthogonal to the first shaft  11 . Then, the third shaft  13  is interlocked and coupled to a third transmission mechanism provided with a third motor and a third reducer. Accordingly, the second arm body  42  is revolved around the third shaft  13 , or is swung in the vertical direction, by the third transmission mechanism (see an arrow  500 ). 
     The fourth joint unit  24  is provided on a tip side of the second arm body  42 . The first wrist  431  is coupled through the fourth joint unit  24 . 
     Note that the wrist unit  43  is constituted of the cylindrical first wrist  431  coupled to the fourth joint unit  24 , the second wrist  432  coupled to the first wrist  431 , and the third wrist  433  provided with the end effector. 
     The fourth joint unit  24 , though which the first wrist  431  is interlocked and coupled, is provided with a fourth shaft  14  extending in a orthogonal direction to the third shaft  13 , or a right and left horizontal direction (X direction) in the drawing. Then, the fourth shaft  14  is interlocked and coupled to a fourth transmission mechanism provided with a fourth motor and a fourth reducer. Accordingly, the first wrist  431  interlocked and coupled in a coaxial direction with the fourth shaft  14  is revolved around the fourth shaft  14 , or is rotated around the fourth shaft  14  by the fourth transmission mechanism (see an arrow  600 ). 
     The fifth joint unit  25  is provided on a tip side of the first wrist  431 , and the second wrist  432  is coupled in the coaxial direction through the fifth joint unit  25 . 
     The fifth joint unit  25  is provided with a fifth shaft  15  extending in the coaxial direction with the fourth shaft  14 , or the right and left horizontal direction (X direction) in the drawing. Then, the fifth shaft  15  is interlocked and coupled to a fifth transmission mechanism provided with a fifth motor and a fifth reducer. Therefore, the second wrist  432  interlocked and coupled in a coaxial direction with the fifth shaft  15  is revolved around the fifth shaft  15 , or is rotated around the fifth shaft  15  by the fifth transmission mechanism (see an arrow  700 ). 
     The sixth joint unit  26  is provided on a tip side of the second wrist  432 , and the third wrist  433  is coupled through the sixth joint unit  26 . 
     The sixth joint unit  26  is provided with a sixth shaft  16  extending in an orthogonal direction to the fifth shaft  15 , or the front and back horizontal direction (Y direction) in the drawing. Then, the sixth shaft  16  is interlocked and coupled to a sixth transmission mechanism provided with a sixth motor and a sixth reducer. Therefore, the third wrist  433  is revolved around the sixth shaft  16 , or is swung in the vertical direction, by the sixth transmission mechanism (see an arrow  800 ). 
     As described above, the robot  1  according to this embodiment is provided with the arm unit  4 , which is revolvably provided to the base  2  provided on the floor  200 , which is a predetermined installation surface. 
     The arm unit  4  is provided with: the arm base body  3  revolvably provided around the first shaft  11 ; the first arm body  41  revolvably provided around the second shaft  12  to the arm base body  3 ; the second arm body  42  revolvably provided around the third shaft  13  to the first arm body  41 ; and the wrist unit  43  revolvably provided to the second arm body  42 . 
     The wrist unit  43  is provided with the first wrist  431 , the second wrist  432 , and the third wrist  433 . The first wrist  431  is revolvably provided around the fourth shaft  14  to the second arm body  42 . The second wrist  432  is revolvably provided around the fifth shaft  15  to the first wrist  431 . The third wrist  433  is revolvably provided around the sixth shaft  16  to the second wrist  432 , and has the predetermined end effector attached to a tip thereof. 
     The arm base body  3 , the first arm body  41 , the second arm body  42 , the first wrist  431 , the second wrist  432 , and the third wrist  433  are a plurality of links revolvably coupled around shafts, and constitute movable parts of the robot  1 . These links are revolved around each of the shafts (the first shaft  11  to the sixth shaft  16 ) by the motor provided to each of the transmission mechanisms. 
     Note that in this embodiment, the arm base body  3  coupled to the base  2  and the wrist unit  43  coupled to the second arm body  42  are included in the arm unit  4 . That is, the arm base body  3  as well as the wrist unit  43 , which is constituted of the first wrist  431 , the second wrist  432 , and the third wrist  433 , are included in a concept of the arm body. 
     As illustrated in  FIG. 2 , the controller  5  provided to the robot system  10  is connected to the robot  1 . The controller  5  is provided with a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and a storage unit such as a hard disk, which are not illustrated. Then, the controller  5  reads a program stored in the storage unit by the CPU, and following the program, drives the arm base body  3 , the first arm body  41 , the second arm body  42 , the first wrist  431 , the second wrist  432 , and the third wrist  433 , which are the links. 
     As illustrated, the controller  5  is also electrically connected to a moving body detection unit  7  constituted of a proximity sensor for detecting movement of a moving body such as the operator  6  within the work area  100 . The moving body detection unit  7  is disposed within the work area  100  independently from the robot  1 . As the moving body detection unit  7 , it is also possible to use a camera capable of monitoring inside of the work area  100  entirely. 
     Then, the controller  5  receives a detection result of the moving body detection unit  7 , and based on the received detection result, when it determines that the operator  6  exists within a predetermined area, for example, it mechanically restricts turning of the arm unit  4  by driving the above-described stopper mechanism  8  provided in the arm unit  4 . That is, the stopper mechanism  8  is capable of making revolving motion of the arm base body  3 , which is an arm body, around the first shaft  11  to be restricted to a predetermined revolving range. 
     Hereinafter, the stopper mechanism  8  according to this embodiment is specifically described with reference to  FIGS. 3 and 4 .  FIG. 3  is an explanatory drawing illustrating a side view of the stopper mechanism  8  provided to the robot  1 , and  FIG. 4  is an explanatory drawing illustrating a plane view of the stopper mechanism  8 . 
     As illustrated in  FIG. 3 , the first projected body  81  is retractably provided on an upper surface of the base  2  as a movable stopper member so as to be positioned on the virtual circumference centering on the first shaft  11 . To make it retractable, here, a hole portion  800  is provided in the base  2  to fit the first projected body  81  in a vertically slidable manner while a cylinder device  820 , which is interlocked and coupled to the first projected body  81 , is arranged thereinside. Then, by driving the cylinder device  820 , the first projected body  81  is made to be retractable from a stopper gateway  810  of the hole portion  800  provided on the upper surface of the base  2 . 
     On the other hand, in the same way, the second projected body  82  is fixedly installed on a lower surface of the arm base body  3  as a fixed stopper member in a state of being projected downward so as to be positioned on the virtual circumference centering on the first shaft  11 . 
     Therefore, when the first projected body  81 , which is the movable stopper member, is in a state of being retracted within the base  2 , the arm base body  3  is turnable centering on the first shaft  11 . However, when the first projected body  81 , which is the movable stopper member, is in a state of being projected from the base  2 , as illustrated in  FIG. 4 , the second projected body  82  of the arm base body  3 , which is turning, eventually abuts against and engages with the first projected body  81 , whereby the turning is restricted. 
     Accordingly, in the robot  1  according to this embodiment, it is possible to mechanically restrict revolving of the arm base body  3  (arm body) by using the movable stopper member. Therefore, reliability can be improved compared to the operation control using the software only, whereby it realizes a configuration that is more preferable as the human-friendly robot  1 . 
     As illustrated in  FIG. 4 , in this embodiment, the plurality of first projected bodies  81 , which is the movable stopper member, is provided around the first shaft  11  at a predetermined interval. That is, among the plurality of first projected bodies  81  provided on the base  2 , by selecting two first projected bodies  81  apart at a predetermined distance so that the second projected body  82  is placed therebetween, which is fixedly installed to the arm base body  3 , and by allowing the two to be projected, it is possible to restrict a revolving range of the arm unit  4  as well as the first arm body  41 . 
     Accordingly, the stopper mechanism  8  according to the embodiment is capable of restricting the revolving motion of the first arm body  41 , which is coupled to the base  2 , to the predetermined revolving range. 
     Therefore, the controller  5  detects the movement of the moving body such as the operator  6 , for example, within the work area  100 , and based on the detection result, it is possible to change a position where the first projected body  81  (movable stopper member) engages with the second projected body  82  (fixed stopper member). 
     For example, the revolving motion of the arm unit  4  can be restricted to a predetermined revolving range according to the position of the operator  6 , for example, whether the operator  6  is in a first area, in a second area, or in a third area that are set in advance within the work area  100 . 
       FIG. 5  is an explanatory drawing illustrating an example of control of the stopper mechanism  8  by the controller  5 . For example, assume that when the revolving range of the arm unit  4  is not restricted, the moving body detection unit  7  detects that the operator  6  has entered the first area (not illustrated), whereby the moving body detection unit  7  transmits a detection result to the controller  5 . 
     The controller  5 , which has not been restricting the revolving range of the arm unit  4  so far, restricts the revolving range of the arm unit  4  to a first range  91  corresponding to the first area when it receives the detection result from the moving body detection unit  7  as illustrated in  FIG. 5 . 
     Specifically, among the plurality of first projected bodies  81  illustrated in  FIG. 4 , by selecting the first projected body  81  inside of a first stopper gateway  810   a  and the first projected body  81  inside of a second stopper gateway  810   b,  for example, and by driving the cylinder device  820 , two first projected bodies  81  are projected. Accordingly, motion of the arm unit  4  is restricted to the first range  91 . 
     In a case where the moving body detection unit  7  detects that the operator  6  has moved even closer to the robot  1  and has entered inside of the second area (not illustrated), for example, the controller  5 , when it detects a detection result from the moving body detection unit  7 , restricts the revolving range of the arm unit  4  to a second range  92  corresponding to the second area as illustrated in  FIG. 5 . 
     Specifically, among the plurality of first projected bodies  81  illustrated in  FIG. 4 , by selecting the first projected body  81  inside of a third stopper gateway  810   c  and the first projected body  81  inside of a fourth stopper gateway  810   d,  for example, and by driving the cylinder device  820 , two first projected bodies  81  are projected. Accordingly, the motion of the arm unit  4  is restricted to the second range  92 . Note that in the stopper mechanism  8  according to this embodiment, as it is clear from the configuration illustrated in  FIG. 4 , the revolving range to which the revolving motion of the arm unit  4  is limited is determined by using a minimum revolving range  90  illustrated in  FIG. 5  as a unit. 
     Incidentally, the above-described stopper mechanism  8  of the robot  1  is configured to have the first projected body  81 , or the movable stopper member, provided to the base  2 , which is one of the links, and the second projected body  82 , or the fixed stopper member, provided to the arm base body  3 . 
     However, it is also possible to reverse positions to arrange the movable stopper member and the fixed stopper member. That is, the movable stopper member may be provided to any one of a pair of links constituted of the base  2  and the arm base body  3 , which are coupled through the first shaft  11 , whereas the fixed stopper member may be provided to any of the other of the links (the base  2  and the arm base body  3 ). 
     The stopper mechanism  8  according to this embodiment is configured to have the fixed stopper member constituted of the second projected body  82 ; however, it is also possible to configure the fixed stopper member by forming an arc-shaped groove portion having a predetermined length on a lower surface of the arm base body  3  by centering on the first shaft  11 , for example. 
     That is, there is formed the groove portion having an groove edge portion formed at a desired position, and the first projected body  81 , which is the movable stopper member, is loosely fit within the groove portion. 
     With this configuration as well, when the arm base body  3  is turned, the first projected body  81  eventually abuts against the groove edge portion, whereby the turning is restricted. 
     In the above-described embodiment, the moving body detection unit  7  is disposed within the work area  100  independently from the robot  1 ; however, the moving body detection unit  7  may also be provided integrally with the robot  1 . 
     Note that restriction of the revolving motion of the arm unit  4  may be controlled as appropriate as an interrupt by using the moving body detection unit  7 , or may be set in advance by determining the revolving range of the arm unit  4 . 
     As described above, the robot  1 , having the above-described configuration according to the embodiment, and the robot system  10  provided with the robot  1  can further improve the reliability in terms of safety and the like of so as to be more suitable as the human-friendly robot. 
     Incidentally, in the above-described embodiment, the stopper mechanism  8  is configured to be provided between the base  2  and the arm base body  3 , and it has been described that the revolving motion of the arm base body  3  can be restricted to the predetermined revolving range. The stopper mechanism  8 , however, may also be capable of restricting the revolving motion of another arm body such as the first arm body  41 , the second arm body  42 , the first wrist  431 , the second wrist  432 , and the third wrist  433  around the shaft to a predetermined revolving range. Alternatively, it may also be capable of restricting the revolving motion of all of the arm bodies around the shaft to the predetermined revolving range. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.