Robot system and robot

Abstract

To accurately bring the orientation of a workpiece to a reference orientation.SOLUTION: A robot system 1 comprises: a work robot 2 that performs work on a workpiece (body 11) transported to a work area 13; a transport vehicle (AMR 6) that transports the workpiece to the work area; a plurality of support robots (locators 4) which have an engaging part 46 that is engaged with the workpiece and a support part (rod 45) that holds the engaging part so that the engaging part rotates in a follower manner when the orientation of the workpiece changes in a state where the engaging part is engaged with the workpiece; and a controller 18 that corrects the orientation of the workpiece via control of the plurality of support robots so that the workpiece handed over from the transport vehicle to the support robots becomes the reference orientation of the workpiece when the work robot performs work on the workpiece.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The technology disclosed herein relates to a robot system and a robot. [Background technology]

[0002] Patent Document 1 describes a conventional robot system. The conventional robot system is used in an assembly line for automobile bodies. On the assembly line, a side member is assembled to an underbody. The conventional robot system includes a first multi-axis robot and a second multi-axis robot. The first multi-axis robot positions the underbody. The second multi-axis robot welds the underbody and the side member together. The conventional robot system also includes an AGV (Automatic Guided Vehicle) that transports the underbody to an assembly area. The AGV travels along a magnetic tape on the floor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6887738 Summary of the Invention [Problem to be solved by the invention]

[0004] In the work area where the robot performs work on the work, a reference orientation of the work is determined. The reference orientation of the work is the orientation of the work when the robot performs work on the work, and is the orientation in a horizontal plane. The reference orientation of the work is usually the orientation along the transport direction when the work is transported to the work area.

[0005] Robot systems used in automobile production lines are required to accurately adjust the orientation of workpieces, because with long workpieces such as automobile bodies, even a slight deviation in orientation can result in a large deviation in position at the ends of the workpiece.

[0006] In the conventional robot system, a workpiece arriving at the work area may be tilted relative to a reference orientation. This is because the AGV transports the workpiece to the work area. A pair of guide rollers and a positioning device are installed in the work area of ​​the conventional robot system. The pair of guide rollers position the AGV in the width direction, and the positioning device positions the AGV in the front-to-rear direction. The combination of the pair of guide rollers and the positioning device does not allow the workpiece to be accurately oriented in the reference orientation. [Means for solving the problem]

[0007] The technology disclosed herein relates to a robot system. a work robot that performs work on the workpiece transported to the work area; a transport vehicle that transports the workpiece to the work area; a plurality of support robots each having an engaging portion that engages with the workpiece, and a support portion that supports the workpiece via the engaging portion while the work robot is working, and that holds the engaging portion so that the engaging portion rotates passively when the orientation of the workpiece changes while the engaging portion is engaged with the workpiece; a controller that corrects the orientation of the workpiece through control of the plurality of support robots so that the workpiece delivered from the transport vehicle to the support robot is in a reference orientation for the workpiece when the work robot performs work on the workpiece; Equipped with. [Effects of the Invention]

[0008] The multiple support robots that receive the workpiece from the transport vehicle correct the orientation of the workpiece, allowing the robot system to accurately orient the workpiece in the reference orientation. When the orientation of the workpiece is corrected, the engagement parts of the support robots rotate passively while engaged with the workpiece. This prevents the workpiece from sliding against the engagement parts or support parts, thereby preventing an increase in the load on the support robot. [Brief explanation of the drawings]

[0009] [Figure 1] Figure 1 shows a robot system applied to an automobile manufacturing line. [Figure 2] Figure 2 shows the robot system. [Figure 3] FIG. 3 is a block diagram of the robot system. [Figure 4] FIG. 4 is a perspective view of the locator. [Figure 5] FIG. 5 is a cross-sectional view taken along line VV of FIG. [Figure 6] FIG. 6 is a block diagram of an autonomous mobile robot (AMR). [Figure 7] Figure 7 shows the procedure for correcting the tilt of a workpiece using a locator. [Figure 8] FIG. 8 is a perspective view schematically showing an engagement state between the engagement portion of the locator and the workpiece. [Figure 9] FIG. 9 is a flowchart showing a procedure for controlling the locator by the locator controller. [Figure 10] FIG. 10 shows a modified version of the sensor. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of a robot system will be described with reference to the drawings. The robot system described here is an example.

[0011] (Overall structure of the robot system) Fig. 1 is a perspective view of the robot system 1 seen from diagonally above. Fig. 2 is a rear view of the robot system 1 seen from behind. The robot system 1 is applied to a production line 10 in an automobile factory. In the illustrated production line 10, welding, more specifically spot welding, is performed on an automobile body 11.

[0012] The front Fr, rear Rr, right Rt, left Lt, top Up, and bottom Lw of the robot system 1 are defined as follows, with the body 11 that is the work target of the robot system 1 as the reference.

[0013] The front Fr of the robot system 1 is the left rear side in the direction connecting the right front and left rear of the paper in Figure 1. The front Fr of the robot system 1 corresponds to the front of the automobile body 11, and the rear Rr of the robot system 1 corresponds to the rear of the automobile body 11. As will be described later, the front-to-rear direction corresponds to the conveyance direction of the body 11.

[0014] The right side Rt of the robot system 1 is the far right side in the direction connecting the front left and rear right of the paper in FIG. 1. The right side Rt of the robot system 1 corresponds to the right side of the automobile body 11. The left side Lt of the robot system 1 corresponds to the left side of the automobile body 11. The left-right direction is a direction that is horizontally perpendicular to the front-rear direction.

[0015] The top (Up) of the robot system 1 is the top side of the paper in Fig. 1, and the bottom (Lw) of the robot system 1 is the bottom side of the paper. The top and bottom of the robot system 1 correspond to the top and bottom of the automobile body 11. The up-down direction is a direction perpendicular to the front-to-rear direction.

[0016] It should be noted that the above definitions are used to explain the robot system 1, and are not used to limit the structure or configuration of the robot system 1 and the elements included in the robot system 1 disclosed herein.

[0017] The robot system 1 includes a robot 2. The robot 2 is an example of a work robot. The robot 2 performs work on a workpiece transported to a work area 13. The work area 13 is located on a path 15 of the AMR 6, which will be described later, and refers to an area where the workpiece transported by the AMR 6 stays to be worked on by the robot 2. The workpiece of the robot 2 is a body 11. The work that the robot 2 performs on the body 11 is welding.

[0018] The robot 2 is a vertical articulated robot having five to seven axes. As shown in Fig. 2, the robot 2 has a welding gun 21 as an end effector. However, the robot 2 is not limited to a vertical articulated robot.

[0019] The robot system 1 includes a plurality of robots 2. The robot system 1 shown in the figure includes 12 robots 2. The 12 robots 2 are located on either side of the body 11. On the right side of the body 11, six robots 2 are lined up in the front-to-rear direction of the body 11. Similarly, on the left side of the body 11, six robots 2 are lined up in the front-to-rear direction of the body 11. Each robot 2 performs welding at a different location on the body 11. The number of robots 2 in the robot system 1 is not limited to a specific number. Furthermore, the arrangement of the robots 2 in the robot system 1 is not limited to a specific arrangement.

[0020] The robot system 1 is equipped with a locator 4. The locator 4 is an example of a support robot. As shown by the dashed dotted line in Figure 2, the locator 4 lifts and supports the body 11 while the robot 2 is working. The locator 4 in the illustration is a three-axis Cartesian robot. The locator 4 has a rod 45 that engages with the body 11. The rod 45 extends in the left-right direction. The tip of the rod 45 engages with the body 11. The locator 4 changes the position of the tip of the rod 45 back and forth, left and right, and up and down. The structure of the locator 4 will be described in detail later.

[0021] The robot system 1 is equipped with a plurality of locators 4. The robot system 1 in the illustration is equipped with four locators 4. The four locators 4 are located on the left and right sides of the body 11. On the right side of the body 11, two locators 41 and 42 are lined up in the front-to-rear direction of the body 11. As shown in FIG. 1 or FIG. 7, the first locator 41 supports the right front end of the body 11, and the second locator 42 supports the right rear end of the body 11. Similarly, on the left side of the body 11, two locators 43 and 44 are lined up in the front-to-rear direction of the body 11. As shown in FIG. 1 or FIG. 7, the third locator 43 supports the left front end of the body 11, and the fourth locator 44 supports the left rear end of the body 11.

[0022] The plurality of locators 4 not only support the body 11 but also correct the inclination of the body 11 as will be described later.

[0023] The robot system 1 includes a support device 5. Note that the support device 5 is not an essential element of the robot system 1. The support device 5, together with the locator 4, supports the body 11 while the robot 2 is working. The support device 5 has the same structure as the locator 4. The support device 5 can also be used as the locator 4.

[0024] The robot system 1 is equipped with a plurality of support devices 5. The robot system 1 in the illustration is equipped with four support devices 5. As shown in FIG. 1 , the four support devices 5 are located on the left and right sides of the body 11. On the right side of the body 11, two support devices 5 are lined up in the front-to-rear direction of the body 11 between the first locator 41 and the second locator 42. The two support devices 5 support the center of the right side of the body 11. Similarly, on the left side of the body 11, two support devices 5 are lined up in the front-to-rear direction of the body 11 between the third locator 43 and the fourth locator 44. The two support devices 5 support the center of the left side of the body 11.

[0025] The robot system 1 is equipped with one or more transport vehicles. The transport vehicles transport workpieces to a work area 13. The transport vehicles are autonomous mobile transport robots (AMRs) 6. The AMR 6 travels on a flat floor in a factory. As illustrated in FIG. 2, a body 11 is placed on a carriage 14. The AMR 6 is positioned below the carriage 14 and engages with the carriage 14. The AMR 6 transports the body 11 via the carriage 14. Note that the AMR 6 may directly support the body 11 without using the carriage 14. Note that the appearance of the AMR 6 shown in FIG. 1 or 2 is an example. The structure of the AMR 6 will be described later.

[0026] 3 is a block diagram of the robot system 1. The robot system 1 includes a system controller 16. The system controller 16 controls the entire robot system 1.

[0027] The robot system 1 includes a robot controller 17. Note that the robot controller 17 is not an essential element of the robot system 1. The robot controller 17 is electrically connected to the system controller 16. The electrical connection includes a wired or wireless connection. The robot controller 17 is also electrically connected to the robot 2. The robot controller 17 and the robot 2 are connected one-to-one. The robot system 1 includes the same number of robot controllers 17 as the number of robots 2.

[0028] The robot controller 17 controls the robot 2. More specifically, the robot controller 17 receives a control signal from the system controller 16 and outputs a control signal to the robot 2. The robot 2 receives the control signal from the robot controller 17 and performs welding work on the body 11.

[0029] The robot system 1 includes a locator controller 18. The locator controller 18 is electrically connected to the system controller 16. The electrical connection may be wired or wireless. The locator controller 18 is also electrically connected to a first locator 41, a second locator 42, a third locator 43, and a fourth locator 44.

[0030] The locator controller 18 controls the locators 4. More specifically, the locator controller 18 receives a control signal from the system controller 16 and outputs a control signal to the first locator 41, the second locator 42, the third locator 43, and the fourth locator 44. The first locator 41, the second locator 42, the third locator 43, and the fourth locator 44 receive the control signal from the locator controller 18 and position and support the body 11 delivered from the AMR 6 at a predetermined position. As will be described later, the locator controller 18 controls the multiple locators 4 in synchronization. The synchronized control enables the multiple locators 4 to correct the inclination of the body 11 and support the body 11.

[0031] The robot system 1 includes a support device controller 20. The support device controller 20 is electrically connected to the system controller 16. The electrical connection may be a wired or wireless connection. The support device controller 20 is also electrically connected to a plurality of support devices 5.

[0032] The support device controller 20 controls the support device 5. More specifically, the support device controller 20 receives a control signal from the system controller 16 and outputs a control signal to the support device 5. The support device 5 receives the control signal from the support device controller 20 and supports the body 11.

[0033] The robot system 1 is equipped with a sensor 19. The sensor 19 is electrically connected to the system controller 16. The sensor 19 outputs a signal related to the inclination of the body 11 that has arrived at the work area 13 to the system controller 16, as will be described in detail later. The sensor 19 includes an external camera 191. The external camera 191 is positioned above the work area 13, as shown in FIG. 2. The external camera 191 photographs the body 11 positioned in the work area 13 from above. The image captured by the external camera 191 is sent to the system controller 16. The system controller 16 determines the degree of inclination of the body 11 in a horizontal plane based on the image captured by the external camera 191.

[0034] (Locator structure) FIG. 4 is a perspective view of the locator 4. FIG. 5 is a VV cross-sectional view of FIG. 4. For the purpose of explaining the locator 4, the directions of the X-axis, Y-axis, and Z-axis are defined as follows. The X-axis is a horizontal axis, and corresponds to the left-right direction of the robot system 1 when the locator 4 is installed in the work area 13. The Y-axis is a horizontal axis and is perpendicular to the X-axis. The Y-axis corresponds to the front-rear direction of the robot system 1 when the locator 4 is installed in the work area 13. The Z-axis is a vertical axis and is perpendicular to the X-axis and Y-axis. The Z-axis corresponds to the up-down direction of the robot system 1 when the locator 4 is installed in the work area 13.

[0035] As described above, the locator 4 is a three-axis Cartesian robot. The rod 45 of the locator 4 supports the body 11 from below. The rod 45 is an example of a support portion. The rod 45 extends in the direction of the X-axis.

[0036] The locator 4 has an engagement portion 46. The engagement portion 46 is located at the tip of the rod 45. The engagement portion 46 has a pin 461. The pin 461 extends in the direction of the Z axis. As shown in FIG. 5 , the pin 461 is inserted into an engagement hole 111 of the body 11 from below. The engagement hole 111 of the body 11 opens downward at the bottom of the body 11. When the pin 461 is inserted into the engagement hole 111, the engagement portion 46 engages with the body 11.

[0037] Rod 45 rotatably holds engaging portion 46. More specifically, rod 45 has a holding hole 451 at its tip. Holding hole 451 is a hole with a circular cross section that opens to the top surface of rod 45 and is recessed downward.

[0038] The engaging portion 46 has a main body 462. The main body 462 is cylindrical. A central axis 463 of the main body 462 extends in the direction of the Z axis. The pin 461 extends upward from the upper end of the main body 462 on the central axis 463. The main body 462 is positioned in the retaining hole 451. The pin 461 protrudes upward from the upper surface of the rod 45.

[0039] The locator 4 has a bearing 452. The bearing 452 is an example of a friction reduction portion. The bearing 452 is interposed between the inner peripheral surface of the retaining hole 451 of the rod 45 and the outer peripheral surface of the main body 462. The bearing 452 in the illustration is a rolling bearing, more specifically, an angular contact ball bearing. An angular contact ball bearing can support both radial loads and axial loads. The bearing 452 rotatably holds the engagement portion 46 engaged with the body 1. The engagement portion 46 rotates around the Z axis. The bearing 452 reduces friction when the engagement portion 46 rotates.

[0040] Incidentally, bearing 452 is not limited to an angular contact ball bearing. A deep groove ball bearing may be used for bearing 452. A deep groove ball bearing is an example of a bearing that can support both radial and axial loads. A thrust bearing may be interposed between retaining hole 451 of rod 45 and main body 462. Furthermore, instead of a rolling bearing, a sliding bearing may be interposed between retaining hole 451 of rod 45 and main body 462. A friction reduction portion that is interposed between rod 45 and engaging portion 46 and reduces friction when engaging portion 46 rotates promotes the following rotation of engaging portion 46 in accordance with a change in the orientation of body 11 during inclination correction of body 11, as will be described later. Incidentally, the holding structure of engaging portion 46 is not limited to the structure described above.

[0041] As shown in FIG. 4, the locator 4 has a base 47. The base 47 is fixed to the floor surface. The locator 4 has a displacement mechanism 410. The displacement mechanism 410 displaces the rod 45 in the X-axis, Y-axis, and Z-axis directions. The displacement mechanism 410 has a first stage 411, a second stage 412, and a third stage 413. The first stage 411 moves relative to the base 47 in the X-axis direction. The second stage 412 moves relative to the first stage 411 in the Y-axis direction. The third stage 413 moves relative to the second stage 412 in the Z-axis direction.

[0042] The control of the support of the body 11 by the locator 4 will be described later.

[0043] (AMR structure) Figure 6 shows the structure of AMR6. The structure of AMR6 in Figure 6 is an example of AMR6.

[0044] The AMR 6 has a plurality of wheels that roll on the floor surface, including two drive wheels 611 and 612 and a passive wheel 621 and a passive wheel 622.

[0045] The two drive wheels 611, 612 are independent. The AMR 6 is an independently driven transport vehicle. The drive wheel 611 is located on the right of the midsection of the AMR 6 in the fore-and-aft direction. The drive wheel 612 is located on the left of the midsection of the AMR 6. The rotation axes of the drive wheels 611 and 612 extend in the left-right direction and are coaxial.

[0046] The drive wheel 611 is mechanically connected to a motor 631. The drive wheel 612 is mechanically connected to a motor 632. The drive wheel 611 and the drive wheel 612 can rotate independently of each other.

[0047] The motors 631, 632 are driven by power supplied from a battery. The battery is mounted on the AMR 6. The motors 631, 632 are driving sources for propelling the AMR 6. The driving force of the motors 631, 632 is transmitted to the drive wheels 611, 612, causing the drive wheels 611, 612 to rotate.

[0048] If the drive wheels 611 and 612 rotate in the same direction at the same rotation speed, the AMR 6 moves straight. If the drive wheels 611 and 612 rotate in the same direction at different rotation speeds, the AMR 6 changes direction of travel.

[0049] When the drive wheels 611 and 612 rotate in opposite directions, the AMR 6 turns on the spot, that is, rotates around a vertical axis. When the drive wheels 611 rotate forward and the drive wheels 612 rotate backward, the AMR 6 rotates counterclockwise in Fig. 6. When the drive wheels 611 rotate backward and the drive wheels 612 rotate forward, the AMR 6 rotates clockwise in Fig. 6.

[0050] The passive wheel 621 is located in the center in the left-right direction at the front end of the AMR 6. The passive wheel 622 is located in the center in the left-right direction at the rear end of the AMR 6. The passive wheels 621 and 622 can each change direction. Note that the AMR 6 may have one passive wheel 621 or one passive wheel 622.

[0051] The AMR 6 has a scanner 65. The scanner 65 acquires information about the surroundings of the AMR 6. The scanner 65 includes, for example, a LiDAR (Light Detection And Ranging) scanner. The scanner 65 is not limited to a LiDAR scanner. The scanners 65 are located at both the front end and the rear end of the AMR 6.

[0052] The AMR 6 has a storage 66. The storage 66 stores various data. The data stored in the storage 66 includes map data 661. The map data 661 is map data of the inside of a factory including the production line 10. Before transporting the body 11, the AMR 6 autonomously travels within the factory in advance, and creates the map data 661 using the scanner 65 while traveling. Note that the AMR 6 may obtain the previously created map data 661 from an external source.

[0053] The AMR 6 has a communication circuit 67. The communication circuit 67 communicates wirelessly with the system controller 16. The communication circuit 67 transmits, for example, position information of the AMR 6 to the system controller 16. The communication circuit 67 receives, for example, information regarding the inclination of the body 11 from the system controller 16.

[0054] The AMR 6 has an AMR controller 69. The AMR controller 69 controls the AMR 6. The AMR controller 69 is electrically connected to the motors 631 and 632, the scanner 65, the storage 66, and the communication circuit 67.

[0055] During the creation of the map data 661, the AMR controller 69 creates the map data 661 based on the signal from the scanner 65 while outputting control signals to the motors 631, 632 to drive the AMR 6. The AMR controller 69 stores the created map data 661 in the storage 66.

[0056] The AMR controller 69 receives control signals from the system controller 16 via the communication circuit 67, and causes the AMR 6 to perform an operation in accordance with the received control signal. The AMR 6 travels to a position specified by the system controller 16, that is, to the work area 13 of the robot 2. When the AMR 6 travels, the AMR controller 69 sets a route 15 for the AMR 6 based on map data 661. While the AMR 6 is traveling, the AMR controller 69 determines the AMR 6's own position based on the signal from the scanner 65 and the map data 661. The AMR 6 autonomously travels to the specified position along the route 15, and the body 11 is transported to the work area 13.

[0057] (Locator Control) Next, a characteristic control of the locator 4 will be described with reference to the drawings. The characteristic control relates to the correction of the tilt of the workpiece by the locator 4. When the AMR 6 arrives at the designated work area 13, the orientation of the AMR 6 may be tilted from a predetermined orientation. This is because the AMR 6 does not require a guide, such as a rail, that mechanically engages to regulate the orientation of the AMR 6. If the orientation of the AMR 6 is tilted, the orientation of the body 11 being transported by the AMR 6 will also be tilted from the reference orientation.

[0058] The AMR 6 can travel while correcting its orientation based on the scan data from the scanner 65. However, if the AMR 6 attempts to accurately correct its orientation while traveling, the correction may take a long time due to repeated small corrections to the orientation of the AMR 6. If the orientation correction takes a long time, it will take a long time to transport the body 11 to the work area 13, reducing the production efficiency of the production line 10.

[0059] The reference orientation of the body 11 is the orientation in a horizontal plane, and is the orientation of the body 11 when the robot 2 performs welding on the body 11. The reference orientation of the body 11 is the orientation along the transport direction when the body 11 is transported to the work area 13. Therefore, the predetermined orientation of the AMR 6 is the orientation along the ideal forward direction of the AMR 6 that has arrived at the work area 13.

[0060] After the body 11 is handed over from the AMR 6, the plurality of locators 41, 42, 43, 44 in the work area 13 correct the inclination of the body 11 with respect to the reference orientation.

[0061] FIG. 7 shows the procedure for correcting the inclination of the body 11 using multiple locators 41, 42, 43, and 44. FIG. 7 shows the work area 13 where the AMR 6 stops, the locators 41, 42, 43, and 44 installed in the work area 13, the AMR 6 located in the work area 13, and the body 11 transported to the work area 13 by the AMR 6. For ease of understanding, the work area 13 in FIG. 7 is drawn sufficiently large compared to the size of the body 11. In FIG. 7, the forward direction of the AMR 6 is downward from the top of the page. The up-down direction on the page in FIG. 7 is the ideal orientation of the AMR 6 upon arrival at the work area 13. The reference orientation of the body 11 is indicated by a dashed line labeled 130.

[0062] The AMR 6 arrives at the work area 13 and stops. The AMR 6 shown in the left diagram of FIG. 7 is tilted clockwise with respect to the ideal orientation. As the AMR 6 tilts, the body 11 also tilts with respect to the reference orientation 130. The amount of tilt of the AMR 6 and the body 11 is an angle θ.

[0063] After the AMR 6 stops in the working area 13, the first locator 41, the second locator 42, the third locator 43, and the fourth locator 44 cause the engaging portions 46 to engage with the body 11.

[0064] Fig. 8 schematically shows the engagement state between the engagement portions 46 of the first locator 41, the second locator 42, the third locator 43, and the fourth locator 44 and the body 11. For ease of understanding, the first locator 41, the second locator 42, the third locator 43, and the fourth locator 44 in Fig. 8 are drawn close to each other. The body 11 is also drawn at a reduced size.

[0065] The engagement portion 46 of the first locator 41 is inserted from below into the engagement hole 111 at the right front end of the body 11. The engagement portion 46 of the second locator 42 is inserted from below into the engagement hole 111 at the right rear end of the body 11. The engagement portion 46 of the third locator 43 is inserted from below into the engagement hole 111 at the left front end of the body 11. The engagement portion 46 of the fourth locator 44 is inserted from below into the engagement hole 111 at the left rear end of the body 11.

[0066] Here, when body 11 arrives at work area 13, it may be tilted with respect to reference orientation 130. If body 11 is tilted, the position of engagement hole 111 of body 11 will be shifted from a predetermined position. Locator controller 18 acquires information regarding angle θ from system controller 16.

[0067] The system controller 16 determines the angle θ based on an image captured by the external camera 191, which image shows the body 11 positioned in the work area 13. The determination of the angle θ based on the image can be performed using known image processing techniques. The system controller 16 transmits a correction command for the body 11 and information on the angle θ to the locator controller 18. Note that the angle θ may be positive when the body 11 is tilted clockwise with respect to the reference orientation 130, and negative when the body 11 is tilted counterclockwise, for example.

[0068] Locator controller 18 receives the correction command for body 11 and information about angle θ. As shown in the left diagram in Fig. 7 , locator controller 18 adjusts the position of rods 45 of first locator 41, second locator 42, third locator 43, and fourth locator 44 in the horizontal plane based on the position of body 11, and engages engagement portions 46 with engagement holes 111 of body 11.

[0069] When the engaging portion 46 engages with the engaging hole 111, the locator controller 18 rotates the body 11 so that the angle θ becomes zero, as shown in the right diagram of Fig. 7. Specifically, the locator controller 18 displaces the rods 45 of the first locator 41, the second locator 42, the third locator 43, and the fourth locator 44 in the X-axis direction, the Y-axis direction, or both the X-axis direction and the Y-axis direction, as shown by the arrows in Fig. 8. As a result, the body 11 rotates about the Z-axis, and the orientation of the body 11 is aligned with the reference orientation 130.

[0070] Here, when the body 11 is rotated by the displacement of the rod 45, the rod 45 and the body 11 rotate relatively around the Z axis. This may result in an increase in the load on the locator 4 due to friction between the rod 45 and the body 11. In contrast, in the locator 4 described above, the rod 45 holds the engaging portion 46 rotatably around the Z axis, i.e., the central axis 463. The engaging portion 46 engaged with the body 11 rotates around the central axis 463 in response to the rotation of the body 11, as shown by the arrow in FIG. 8 . This suppresses an increase in the load on the locator 4 due to sliding between the rod 45 and the body 11.

[0071] Once the tilt of the body 11 is corrected, the locator 4 further lifts the body 11 to a position for welding. When the body 11 is being welded, the body 11 is separated upward from the carriage 14.

[0072] Fig. 9 is a flowchart showing the control procedure of locator 4 by locator controller 18. In the flow of Fig. 9, the order of steps can be changed, some steps can be omitted, and other steps can be added to the extent possible.

[0073] In step S11 after starting, locator controller 18 determines whether or not it has received information from system controller 16 that AMR 6 has stopped in work area 13. After receiving the information that AMR 6 has stopped, locator controller 18 receives information regarding angle θ of body 11 from system controller 16 in step S12.

[0074] In step S13, based on the information regarding the angle θ, the locator controller 18 causes the engagement portions 46 of the first locator 41, the second locator 42, the third locator 43, and the fourth locator 44 to engage with the engagement holes 111 of the body 11. In the following step S14, the locator controller 18 determines whether the angle θ is zero.

[0075] If the angle θ is not zero, the locator controller 18 corrects the inclination of the body 11 in step S15. Specifically, the locator controller 18 synchronously displaces the rods 45 of the four locators 4 within the horizontal plane. After correcting the inclination, in step S14, the locator controller 18 determines whether the angle θ is zero based on the information about the angle θ received again from the system controller 16. The locator controller 18 repeats steps S14 and S15 until the angle θ becomes zero.

[0076] When the angle θ becomes zero, in step S16, the locator controller 18 causes the locator 4 to support the body 11. The body 11 is lifted from the carriage 14 as shown by the dashed line in FIG. 2. The system controller 16 commands the robot 2 to weld the body 11. The robot 2 performs welding on the body 11 in accordance with the command.

[0077] In step S17, the locator controller 18 determines whether or not a signal to end welding on the body 11 has been received. The locator 4 continues to support the body 11 in step S16 until the locator controller 18 receives the end signal. If the locator controller 18 receives the end signal, the locator controller 18 ends supporting the body 11 in step S18. The body 11 is handed over from the locator 4 to the carriage 14. Note that the AMR 6 may rotate in place between steps S16 and S18 so that its angle is the same as that of the body 11.

[0078] 9 returns to step S11. Locator controller 18 waits for the next AMR 6 to arrive at work area 13.

[0079] It should be noted that if the angle θ of the body 11 is zero when the AMR 6 stops in the working area 13 in step S14, the locator controller 18 does not perform the tilt correction in step S15.

[0080] (Action and effect) The AMR 6 does not require a running guide. As shown in Figure 1 or 2, a production line 10 equipped with the AMR 6 has the advantage of not requiring the pits required in conventional production lines for laying body transport rails and body elevators. Another advantage is that, because the floor in the factory is flat, the production line 10 equipped with the AMR 6 can easily accommodate layout changes.

[0081] Furthermore, using an AMR6 in the production line 10 enables production adjustments by adjusting the number of AMR6s, thereby realizing flexible operation of the production line 10.

[0082] The robot system 1 can correct the orientation of the body 11 using the locator 4 after the AMR 6 arrives at the work area 13. The robot system 1 can use the locator 4 to match the orientation of the body 11 with the reference orientation 130 with high accuracy.

[0083] The AMR 6 does not need to precisely adjust the orientation of the body 11 while traveling to the work area 13 or immediately before stopping in the work area 13 in order to align the orientation of the body 11 with the reference orientation 130. The AMR 6 can quickly move to the work area 13. Furthermore, the multiple locators 4 rotate the body 11 around the vertical axis while supporting it, so the orientation of the body 11 can be quickly and accurately corrected. After the AMR 6 arrives at the work area 13, the robot 2 can quickly start welding. The robot system 1 reduces the time required to transport the body 11, thereby improving the production efficiency of the production line 10.

[0084] Furthermore, the robot system 1 can obtain accurate information about the orientation of the body 11 in the work area 13 using a sensor 19 external to the AMR 6. The robot system 1 can correct the orientation of the body 11 with high accuracy using a simple system.

[0085] Furthermore, since the locator 4 has a rotatable engaging portion 46, friction between the rod 45 of the locator 4 and the body 11 is suppressed when the tilt of the body 11 is corrected by synchronous control of multiple locators 4. This suppresses an increase in the load on the locator 4.

[0086] Since the locator 4 has a bearing 452 as a friction reducing portion, the friction force between the engaging portion 46 and the rod 45 is lower than the friction force between the body 11 and the engaging portion 46. The engaging portion 46 rotates relative to the rod 45 following the rotation of the body 11. An increase in the load on the locator 4 can be effectively suppressed.

[0087] (Variation) The locator as the support robot is not limited to a three-axis Cartesian robot, and the support robot may be an articulated robot.

[0088] The AMR 6 is not limited to the structure shown in Figure 6. The AMR 6 may have omnidirectional wheels such as Mecanum wheels or omni-wheels. Furthermore, the AMR 6 may not be an independently driven transport vehicle, but may instead have a steering mechanism.

[0089] The AMR 6 may have a rotary table. The rotary table rotates clockwise and counterclockwise around a vertical axis on the upper surface of the AMR 6. The rotary table rotates relative to the main body of the AMR 6. When the rotary table rotates, the body 11 rotates around the vertical axis via the carriage 14. The body 11 rotates in place without moving forward / backward or left / right. The rotary table can correct the orientation of the body 11. The rotary table of the AMR 6 increases the degree of freedom in correcting the orientation of the body 11 in the robot system 1.

[0090] The robot system 1 may include an AGV as a transport vehicle. Like the AMR 6, the AGV may tilt from a predetermined orientation when stopped in the work area 13. The control for correcting the orientation of the body 11 described above is also effective for the robot system 1 including an AGV.

[0091] 9, the process may proceed to step S16 without returning to step S14. In other words, if locator controller 18 corrects the orientation of body 11 via locator 4 based on angle θ received in step S12 so that angle θ becomes zero, confirmation of angle θ may be omitted.

[0092] 9, locator controller 18 may determine whether angle θ is substantially zero. That is, in step S14, locator controller 18 may determine whether angle θ is within the range of 0±α°. α can be set to an appropriate angle.

[0093] The system controller 16 may be omitted from the robot system 1. The robot system 1 may achieve the above-described control by mutual communication between the robot controller 17, the locator controller 18, and the AMR 6.

[0094] The number of external cameras 191 is not limited to one, and may be two or more. Multiple cameras may be installed at appropriate positions. The system controller 16 may determine the angle θ of the body 11 based on a composite image obtained by combining images captured by the multiple cameras.

[0095] The external camera 191 may be attached to the robot 2 instead of being fixed to the factory building, as shown in FIG.

[0096] Furthermore, the AMR 6 may have one or more cameras instead of or in addition to the external camera 191. The system controller 16 or the AMR 6 may determine the angle θ of the body 11 using an image captured by the camera of the AMR 6.

[0097] The system controller 16 may determine the angle θ of the body 11 based on measurement signals from one or more distance measuring sensors instead of an image captured by a camera. Fig. 10 shows the robot system 1 using a distance measuring sensor 194 as the external sensor 19. Various types of known sensors can be used as the distance measuring sensor 194.

[0098] 10, distance measurement sensors 194 are attached to locator 4. Each distance measurement sensor 194 measures the distance to body 11 stopped in work area 13. System controller 16 can determine the inclination of body 11 based on measurement signals from multiple distance measurement sensors 194. Note that distance measurement sensors 194 can be installed in any suitable location.

[0099] It should be noted that the work performed by the robot system 1 disclosed herein in the manufacturing line 10 is not limited to welding. Furthermore, the workpiece that the robot system 1 acts on is not limited to the automobile body 11. Furthermore, the robot system 1 is not limited to application to the automobile manufacturing line 10.

[0100] The functions of the elements disclosed herein can be performed using circuits or processing circuits, including general-purpose processors, special-purpose processors, integrated circuits, ASICs (Application Specific Integrated Circuits), conventional circuits, and / or combinations thereof, configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuitry. In this disclosure, a circuit, unit, or means is hardware that performs the recited functions or hardware that is programmed to perform the recited functions. The hardware may be hardware disclosed herein or other known hardware that is programmed or configured to perform the recited functions. Where the hardware is a processor, which is considered a type of circuit, the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or processor.

[0101] (Aspect) The above-described embodiments are examples of the following aspects.

[0102] (Aspect 1) a work robot (2) that performs work on a workpiece (11) transported to a work area (13); a transport vehicle (6) that transports the work (11) to the work area (13); a plurality of support robots (4), each having an engaging portion (46) that engages with the workpiece (11), and a support portion (45) that supports the workpiece (11) via the engaging portion (46) while the working robot (2) is working, and that holds the engaging portion (46) so that the engaging portion (46) rotates in a driven manner when the orientation of the workpiece (11) changes while the engaging portion (46) is engaged with the workpiece (11); a controller (18) that corrects the orientation of the workpiece (11) through control of the plurality of support robots (4) so ​​that the workpiece (11) delivered from the transport vehicle (6) to the support robot (4) is in a reference orientation of the workpiece (11) when the work robot (2) performs work on the workpiece (11); A robot system (1) comprising:

[0103] The robot system (1) uses the support robot (4) to accurately align the orientation of the workpiece (11) in the work area (13) with the reference orientation (130).

[0104] The support robot (4) has an engagement portion (46) that is rotatably held on the support portion (45), so that when correcting the orientation of the workpiece (11), the workpiece (11) can be prevented from rubbing against the engagement portion (46) or the support portion (45).

[0105] (Aspect 2) The engaging portion (46) rotates around a vertical Z axis, the support robot (4) further includes a displacement mechanism (410) that displaces the support part (45) in the Z-axis direction and in the X-axis and Y-axis directions that are orthogonal to each other in a horizontal plane; The engaging portions (46) of the plurality of support robots (4) engage with a plurality of portions of the workpiece (11), The robot system (1) according to aspect 1, wherein the controller (18) corrects the orientation of the workpiece (11) by synchronously displacing the plurality of support portions (45) in the horizontal direction.

[0106] The orientation of the workpiece (11) in the horizontal plane is effectively corrected by the synchronized displacement of the multiple support portions (45).

[0107] (Aspect 3) a sensor (19) that outputs a signal related to the orientation of the workpiece (11) that has arrived at the work area (13) and been handed over from the transport vehicle (6) to the support robot (4); The robot system (1) according to aspect 1 or aspect 2, wherein the controller (18) corrects the orientation of the workpiece (11) based on a signal from the sensor (19).

[0108] The robot system (1) can obtain accurate information about the orientation of the workpiece (11) in the work area (13) using an external sensor (19). The robot system (1) can achieve highly accurate correction of the orientation of the workpiece (11) using a simple system.

[0109] (Aspect 4) The robot system (1) according to any one of aspects 1 to 3, wherein the transport vehicle is an autonomous transport robot (6).

[0110] The autonomous mobile transport robot (6) can transport the workpiece (11) to the work area (13) by traveling on a flat floor. No pit is required for transporting the workpiece (11). The use of the autonomous mobile transport robot (6) also has the advantage of being able to easily accommodate changes to the layout of the production line.

[0111] The autonomous mobile transport robot (6) does not need to precisely adjust the orientation of the workpiece (11) while transporting the workpiece (11) to the work area (13). This is because the support robot (4) corrects the orientation of the workpiece (11) in the work area (13). The autonomous mobile transport robot (6) can quickly move to the work area (13). The robot system (1) can reduce the time required to transport the workpiece (11), including positioning the workpiece (11).

[0112] (Aspect 5) an engaging portion (46) that engages with the workpiece (11); a support portion (45) that supports the workpiece (11) via the engaging portion (46) and holds the engaging portion (46) so that the engaging portion (46) rotates following the rotation of the workpiece (11) when the orientation of the workpiece (11) changes while the engaging portion (46) is engaged with the workpiece (11); A robot (4).

[0113] The engaging portion (46), which rotates following the change in the orientation of the workpiece (11), has a simple structure and can effectively suppress an increase in the load on the support robot (4).

[0114] (Aspect 6) The robot (4) according to aspect 5, further comprising a friction reduction portion (452) interposed between the engagement portion (46) and the support portion (45) and reducing friction when the engagement portion (46) rotates.

[0115] The friction reducing portion (452) reduces friction between the engaging portion (46) and the support portion (45), so that the engaging portion (46) can rotate in response to changes in the orientation of the workpiece (11).

[0116] (Aspect 7) A robot (4) according to aspect 6, wherein the friction reducing portion is a bearing (452).

[0117] The bearing (452) effectively reduces friction between the engaging portion (46) and the support portion (45) with a simple structure.

[0118] (Aspect 8) The support is a rod (45) extending in the direction of the horizontal X-axis, The engaging portion (46) has a pin (461) that extends in the direction of the vertical Z-axis at the tip of the rod (45) and is inserted into an engaging hole (111) of the work (11), and rotates around the Z-axis, a displacement mechanism (410) that displaces the rod (45) in the directions of the X-axis, the Z-axis, and a horizontal Y-axis perpendicular to the X-axis and the Z-axis; The robot (4) according to any one of aspects 5 to 7, wherein the displacement mechanism (410) adjusts the orientation of the workpiece (11) by horizontally displacing the rod (45) while the pin (461) is inserted into the engagement hole (111) and the rod (45) is supporting the workpiece (11).

[0119] The horizontally extending rod (45) and the engagement portion (46) at the tip of the rod (45), which rotates around the vertical Z-axis, enable adjustment of the orientation and support of the workpiece (11) while suppressing an increase in the load on the support robot (4). [Explanation of symbols]

[0120] 1. Robot System 11 Body (work) 111 Engagement hole 13 Work Area 130 Reference Orientation 18 Locator Controller 19 Sensors 191 External camera (sensor) 194 Distance Sensor (Sensor) 2. Robots (working robots) 4 Locator (support robot) 410 Displacement Mechanism 45 Rod (support part) 452 Bearing (friction reduction part) 46 Engagement part 461 pins 6 AMR (transport vehicle)

Claims

1. a work robot that performs work on the workpiece transported to the work area; a transport vehicle that transports the workpiece to the work area; a plurality of support robots each having an engaging portion that engages with the workpiece, and a support portion that supports the workpiece via the engaging portion while the work robot is working, and that holds the engaging portion so that the engaging portion rotates passively when the orientation of the workpiece changes while the engaging portion is engaged with the workpiece; a controller that corrects the orientation of the workpiece through control of the plurality of support robots so that the workpiece delivered from the transport vehicle to the support robot will be in a reference orientation for the workpiece when the work robot performs work on the workpiece; A robot system comprising:

2. 2. The robot system according to claim 1, The engagement portion rotates around a vertical Z axis, the support robot has a displacement mechanism that displaces the support part in the Z-axis direction and in the X-axis and Y-axis directions that are orthogonal to each other in a horizontal plane, the engaging portions of the plurality of support robots engage with a plurality of portions of the workpiece, The controller corrects the orientation of the workpiece by synchronously displacing the plurality of support parts in a horizontal direction.

3. 3. The robot system according to claim 1, a sensor that outputs a signal related to the orientation of the workpiece that has arrived at the work area and been handed over from the transport vehicle to the support robot; The controller corrects the orientation of the workpiece based on the signal from the sensor.

4. 2. The robot system according to claim 1, The robot system, wherein the transport vehicle is an autonomous transport robot.

5. an engagement portion that engages with the workpiece; a support portion that supports the workpiece via the engaging portion and holds the engaging portion so that the engaging portion rotates in response to a change in orientation of the workpiece while the engaging portion is engaged with the workpiece; A robot equipped with:

6. The robot according to claim 5, The robot further includes a friction reduction portion interposed between the engagement portion and the support portion, the friction reduction portion reducing friction when the engagement portion rotates.

7. 7. The robot according to claim 6, The robot, wherein the friction reducing portion is a bearing.

8. The robot according to any one of claims 5 to 7, the support portion is a rod extending in the direction of a horizontal X-axis, the engaging portion has a pin that extends in the direction of the vertical Z-axis at the tip of the rod and is inserted into an engaging hole of the workpiece, and rotates around the Z-axis; a displacement mechanism that displaces the rod in the directions of the X-axis, the Z-axis, and a horizontal Y-axis perpendicular to the X-axis and the Z-axis; The displacement mechanism adjusts the orientation of the workpiece by horizontally displacing the rod while the pin is inserted into the engagement hole and the rod supports the workpiece.

Images