Patent Publication Number: US-2021162961-A1

Title: Automated guided robot system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority to Japanese Patent Application No. 2019-214901 filed on Nov. 28, 2019, the content of which is incorporated herein by reference in its entirety. 
     FIELD 
     The present disclosure relates to an automated guided robot system. 
     BACKGROUND 
     There is a known arranging robot that travels with a manipulator mounted thereon, the manipulator having a hand unit equipped with a sensor, such as a laser sensor or a camera (for example, Japanese Unexamined Patent Application, Publication No. 2012-139792). 
     When this arranging robot moves, the manipulator is actuated to perform measurement with the sensor so that the arranging robot is automatically controlled based on the acquired information. When an object is to be gripped by the manipulator, the manipulator is actuated to perform measurement with the sensor, and the gripping task of the manipulator is automatically controlled based on the acquired information. 
     SUMMARY 
     An aspect of the present disclosure provides an automated guided robot system that includes an automated guided vehicle, a robot mounted on the automated guided vehicle, and a sensor mounted on the robot and capable of detecting statuses of multiple maintenance parts of the automated guided vehicle, in which the robot has a motion range that enables the robot to place the sensor at positions from which the statuses of the maintenance parts of the automated guided vehicle are detectable. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of an automated guided robot system according to one embodiment of the present disclosure. 
         FIG. 2  is a schematic plan view illustrating one example of a travel path of an automated guided vehicle of the automated guided robot system illustrated in  FIG. 1 . 
         FIG. 3  is a perspective view illustrating one example of the posture of a robot that detects the status of an obstacle sensor with the automated guided robot system illustrated in  FIG. 1 . 
         FIG. 4  is a perspective view illustrating one example of the posture of the robot that detects the status of tires with the automated guided robot system illustrated in  FIG. 1 . 
         FIG. 5  is a perspective view illustrating one example of the posture of the robot that detects the status of an indicator lamp with the automated guided robot system illustrated in  FIG. 1 . 
         FIG. 6  is a block diagram illustrating a controller of the automated guided robot system illustrated in  FIG. 1 . 
         FIG. 7  is a perspective view illustrating one example of the posture of the robot that detects vibrations with an acceleration sensor in the automated guided robot system illustrated in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     An automated guided robot system  1  according to one embodiment of the present disclosure will now be described with reference to the drawings. 
     As illustrated in  FIG. 1 , the automated guided robot system  1  according to this embodiment is equipped with an autonomous automated guided vehicle  2  that can travel on a road; a robot  3  mounted on the automated guided vehicle  2 ; a sensor  4  mounted on the robot  3 , and a controller (control unit)  5  that is mounted on the automated guided vehicle  2  and controls the robot  3  and the automated guided vehicle  2 . 
     The automated guided vehicle  2  is a steerable four-wheel vehicle having an upper surface on which the robot  3  is mounted. A table  6  on which a workpiece and the like are loaded is disposed within the motion range of the robot  3 . 
     As illustrated in  FIG. 2 , the automated guided vehicle  2  is guided along a predetermined travel path C between work stations A and B in order for the robot  3  to perform tasks at these work stations A and B. The travel path C is stored in the controller  5 , and the automated guided vehicle  2  is caused to move along the travel path C by a desired method such as GPS, SLAM, or magnetic induction. 
     The robot  3  is, for example, a six-axis articulated robot. The robot  3  is equipped with a base  7  fixed to the upper surface of the automated guided vehicle  2 , and a swivel barrel  8  rotatably supported relative to the base  7  about a vertical first axis J 1 . The robot  3  is also equipped with a first arm  9  rotatably supported relative to the swivel barrel  8  about a horizontal second axis J 2 , and a second arm  10  rotatably supported relative to the first arm  9  about a third axis J 3  parallel to the second axis J 2 . Moreover, the robot  3  is equipped with a three-axis wrist unit  11  at the distal end of the second arm  10 . 
     A hand  12 , which is a tool that performs a task such as gripping a workpiece, is attached to the distal end of the wrist unit  11  of the robot  3 . The wrist unit  11  may be positioned at any desired three-dimensional position within the motion range by combining the movements of the swivel barrel  8  relative to the base  7 , the first arm  9  relative to the swivel barrel  8 , and the second arm  10  relative to the first arm  9 . In addition, the position of the hand  12  can be moved as desired by actuating the three-axis wrist unit  11 . 
     The sensor  4  is, for example, a camera that acquires a two-dimensional image. In this embodiment, the sensor  4  is fixed to the hand  12 . In this manner, when the hand  12  is moved to a desired posture at the desired three-dimensional position by the operation of the robot  3 , the sensor  4  can also be arranged at a desired posture at the desired three-dimensional position. 
     In this embodiment, the robot  3  has a motion range with which the sensor  4  can be arranged to face multiple maintenance parts  13 ,  14 , and  15  of the automated guided vehicle  2 . Examples of the maintenance parts include an obstacle sensor  13  installed on a front surface of the automated guided vehicle  2  to detect obstacles and the like in front of the traveling automated guided vehicle  2  in the travelling direction. Other examples of the maintenance parts include an indicator lamp  15  and four tires  14 . 
     In order to detect the status of the obstacle sensor  13 , the robot  3  is moved to the posture illustrated in  FIG. 3  so that the sensor  4  faces the obstacle sensor  13  and the obstacle sensor  13  is placed within the detection range of the sensor  4 . In this manner, the image of the appearance of the obstacle sensor  13  can be acquired through the sensor  4 . 
     In order to detect the statuses of the tires  14 , the robot  3  is moved, for example, to the posture illustrated in  FIG. 4 . The sensor  4  is faced with each of the tires  14  to place each of the tires  14  within the detection range of the sensor  4 . In this manner, images of the appearances of each of the tires  14  can be acquired through the sensor  4 . 
     In order to detect the status of the indicator lamp  15 , the robot  3  is moved to the posture illustrated in  FIG. 5  so that the sensor  4  faces the indicator lamp  15  and the indicator lamp  15  is placed within the detection range of the sensor  4 , and the indicator lamp  15  is turned ON and OFF. 
     In this manner, images of the indicator lamp  15  when a turn-on command is output and when a turn-off command is output can be acquired through the sensor  4 . 
     As illustrated in  FIG. 6 , the controller  5  includes a storage  16  that stores a program and the like, and a control unit  17  that controls the robot  3  and the automated guided vehicle  2  according to the program stored in the storage  16 . In addition, the controller  5  also includes a judgment unit  18  that judges whether maintenance is necessary based on the images acquired through the sensor  4 , and a notifying unit  19  that issues a notification when it is judged that the maintenance is necessary. The storage  16  is constituted by a memory, and the control unit  17  and the judgment unit  18  are constituted by a processor and a memory. 
     Examples of the statuses of the maintenance parts  13 ,  14 , and  15  include whether there are dents or deformation in the obstacle sensor  13 , whether there is wear or a puncture in the tires  14 , whether the indicator lamp  15  is damaged, and whether the indicator lamp  15  can display an indicator as commanded. 
     According to the program stored in the storage  16 , the control unit  17  actuates the robot  3  to each of the positions for maintenance described above on a regular basis, actuates the sensor  4 , and actuates the indicator lamp  15  of the automated guided vehicle  2 . The judgment unit  18  then judges whether the maintenance parts  13 ,  14 , and  15  require maintenance based on the images acquired through the sensor  4 . 
     For example, when the status of the maintenance parts  13 ,  14 , and  15  detected through the sensor  4  is the wear status of the tires  14 , the judgment unit  18  processes the image to extract the groove depth of the treads or the size of the slip sign, for example. Then the judgment unit  18  compares the extracted status with the threshold value stored in the storage  16  so as to judge whether maintenance is necessary. 
     Meanwhile, when the status of the maintenance parts  13 ,  14 , and  15  detected through the sensor  4  is whether there are dents or deformation in the obstacle sensor  13 , whether there is a puncture in the tires  14 , whether the indicator lamp  15  is damaged, or whether the indicator lamp  15  can display as commanded, the judgment unit  18  can judge the necessity for maintenance by using the images. 
     For example, the judgment unit  18  may compare the acquired image with an image of a normal status stored in the storage  16  and judge whether the maintenance is necessary. Alternatively, the judgment unit  18  may judge whether the maintenance is necessary by inputting the acquired image into a learned model generated by machine learning in advance. 
     The timing for performing the operation of confirming the necessity for maintenance of the maintenance parts  13 ,  14 , and  15  may be set based on the cumulative time counted by a timer (not illustrated) or may be set at a start or end time of daily operation. 
     The notifying unit  19  may be any desired means that is capable of informing externally the notification of maintenance necessity, and examples thereof include a monitor, a speaker, and an indicator lamp. 
     The operation of the automated guided robot system  1  according to this embodiment having the aforementioned features will now be described. 
     Described below is the case in which the automated guided robot system  1  of this embodiment has reached the timing at which the operation of confirming the necessity for maintenance is to be performed. 
     In this case, the controller  5  actuates the robot  3 , and, as illustrated in  FIGS. 3 to 5 , the maintenance parts  13 ,  14 , and  15  are placed within the detection range of the sensor  4  attached to the hand  12 . In this state, images of the appearances of the maintenance parts  13 ,  14 , and  15  are acquired through the sensor  4  and sent to the judgment unit  18 . 
     Next, based on the acquired images, whether maintenance is necessary is judged by the judgment unit  18 , and when it is judged that maintenance is necessary, a notification is issued from the notifying unit  19 . 
     According to the automated guided robot system  1  of this embodiment, since the statuses of the maintenance parts  13 ,  14 , and  15  are detected by using the sensor  4  mounted on the robot  3 , the sensor  4  that detects the status does not have to be provided for each of the maintenance parts  13 ,  14 , and  15 . In other words, the statuses of the maintenance parts  13 ,  14 , and  15  can be detected by using a single sensor  4 . This offers an advantage in that the cost of the automated guided robot system  1  can be reduced. 
     In addition, since the robot  3  mounted on the automated guided vehicle  2  places the sensor  4  at positions from which the statuses of the maintenance parts  13 ,  14 , and  15  are detectable, whether the maintenance is necessary can be confirmed without designating the time and place for the automated guided vehicle  2  that moves over a wide range. 
     In this embodiment, the sensor  4  is constituted by a camera, and two-dimensional images of the appearances of the maintenance parts  13 ,  14 , and  15  are acquired. Alternatively, a camera that can acquire three-dimensional images or a sensor  4  other than a camera may be used. For example, a distance sensor that uses a laser beam may be employed. 
     In this embodiment, the obstacle sensor  13 , the indicator lamp  15 , and four tires  14  are used as the examples of the maintenance parts. In addition, a contact sensor, such as a bumper, may be installed as the maintenance part on the automated guided vehicle  2 . 
     In such a case, the robot  3  presses the contact sensor with the second arm  10 , the wrist unit  11 , or the hand  12 , and the motor torque of the robot  3  or a force sensor mounted on the hand  12  is used to confirm the pressing. When the pressing is confirmed by the robot  3  side and the pressing is also detected with the contact sensor on the automated guided vehicle  2  side, it is judged that maintenance is not necessary. 
     Alternatively, an acceleration sensor or a microphone may be employed as the sensor  4 . In this case, in particular, abnormities in the driving system (a motor or a reducer) of the automated guided vehicle  2  can be detected through the amplitude of vibrations or the intensity of abnormal noise. 
     In such a case, detection needs to be conducted while running the driving system of the automated guided vehicle  2 ; however, detection conducted while the automated guided vehicle  2  is travelling on the road is susceptible to disturbances caused by road conditions. Thus, preferably, detection of the statuses of the maintenance parts  13 ,  14 , and  15  is conducted after the control unit  17  commands the automated guided vehicle  2  to move the tires  14  to a place where idling can be performed, such as by jacking up the vehicle. 
     When abnormal noise is to be detected with a microphone, the robot  3  may be actuated to bring the microphone attached to the distal end of the robot  3  close to the driving system. In addition, when vibrations are to be detected with the acceleration sensor  20 , as illustrated in  FIG. 7 , the arms  9  and  10  of the robot  3  are extended as much as possible to amplify the amplitudes of vibrations at the position of the acceleration sensor  20  attached to the distal end of the robot  3 . In this manner, the sensitivity of the sensors  4  and  20  can be improved, and the statuses of the maintenance parts  13 ,  14 , and  15  can be detected highly accurately. 
     Moreover, as described above, when different types of statuses need to be detected, such as when the appearance needs to be detected for some of the maintenance parts  13 ,  14 , and  15  and vibrations or abnormal noise needs to be detected for other maintenance parts  13 ,  14 , and  15 , different types of sensors  4  can be mounted on the automated guided vehicle  2 . In such a case, a sensor changing device similar to an automatic tool changer (ATC) for the sensor  4  may be installed on the robot  3 , and the sensors  4  may be changed in accordance with the maintenance parts  13 ,  14 , and  15  from which the status is to be detected. 
     In this embodiment, the judgment unit  18  for judging whether the maintenance of the maintenance parts  13 ,  14 , and  15  is necessary is provided; alternatively, a maintenance time estimation unit (not illustrated) that estimates the time when maintenance of the maintenance parts  13 ,  14 , and  15  becomes necessary may be provided. In addition, the notifying unit  19  may be an estimated time notifying unit that issues a notification of the time estimated by the maintenance time estimation unit to the outside through a display on a monitor, a sound, the color of an indicator lamp, or the like. 
     In addition, the maintenance time estimation unit may estimate the maintenance time by inputting the statuses of the maintenance parts  13 ,  14 , and  15  acquired through the sensor  4  into a learned model generated by machine learning in advance. 
     In this embodiment, a six-axis articulated robot is employed as the robot  3 ; alternatively, a seven-axis articulated robot or a different type of robot may be employed. 
     Moreover, although an example in which the sensor  4  is fixed to the hand  12  is described, the sensor  4  may be fixed to the swivel barrel  8 , the first arm  9 , the second arm  10 , or the wrist unit  11 . 
     When the sensor  4  is fixed to the swivel barrel  8 , an adapter may be used to offset the fixed position of the sensor  4  from the top surface of the automated guided vehicle  2  so that the sensor  4  protrudes from the top surface and the statuses of the maintenance parts  13 ,  14 , and  15  can be detected. 
     In this embodiment, an example in which the robot  3  and the automated guided vehicle  2  are controlled by a single controller  5  is described; alternatively, multiple controllers  5  may be provided, one of which controls the robot  3  and another one of which controls the automated guided vehicle  2 . 
     Alternatively, in this embodiment, the robot  3  may perform the maintenance operation automatically. 
     Specifically, when a loose bolt is detected, by a camera serving as the sensor  4 , from the maintenance target in the automated guided robot system  1 , the ATC changes the hand  12  to a hand for tightening a bolt and performs retightening of the loose bolt. 
     In addition, when contamination is detected by a camera serving as the sensor  4  from the maintenance target in the automated guided robot system  1 , the ATC changes the hand  12  to a hand for cleaning and performs cleaning of the contaminated region. 
     Moreover, when changing of parts has become necessary as a result of maintenance judgment, the ATC changes the hand  12  so that the parts can be changed to spare parts stored in the spare part storage or the like.