Door opening and closing robot and door opening and closing system

Abstract

To achieve space saving.SOLUTION: A door opening / closing robot includes: a base positioned at a position different from a conveyance line where a vehicle body is conveyed; a first arm which is mounted on the base so as to rotate around a first axis, and extends in a direction away from the first axis; a second arm which is mounted on the first arm so as to rotate around a second axis parallel to the first axis, and extends in a direction away from the second axis; a third arm which is mounted on the second arm so as to rotate around a third axis parallel to the first axis, and extends in a direction away from the third axis; and a fourth arm which is mounted on the third arm so as to extend in a vertical direction, and moves a tool capable of holding a door mounted on the vehicle body in the vertical direction. At least a part of a connection part including the tip of the second arm and the base end of the third arm, and at least a part of the base are positioned at the same height.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a door opening and closing robot and a door opening and closing system. [Background technology]

[0002] Patent document 1 discloses a painting system that includes multiple painting robots that are fixed in a painting booth and paint vehicles that are transported in a predetermined transport direction, and an operating robot that operates the vehicle's opening and closing members. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-126831 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a door opening / closing robot and a door opening / closing system that are useful for saving space. [Means for solving the problem]

[0005] A door opening / closing robot according to one aspect of the present disclosure includes: a base provided at a position different from a conveyor line along which a vehicle body to be worked on is conveyed; a first arm attached to the base so as to rotate about a first axis along the vertical direction and extending in a direction away from the first axis; a second arm attached to the first arm so as to rotate about a second axis parallel to the first axis and extending in a direction away from the second axis; a third arm attached to the second arm so as to rotate about a third axis parallel to the first axis and extending in a direction away from the third axis; and a fourth arm attached to the third arm at a tip end of the third arm so as to extend in the vertical direction, the fourth arm moving a tool capable of holding a door attached to the vehicle body in the vertical direction. At least a portion of a connecting portion including the tip end of the second arm and the base end of the third arm and at least a portion of the base are located at the same height in the vertical direction.

[0006] A door opening / closing robot according to one aspect of the present disclosure includes a base provided at a position different from the conveyor line along which a vehicle body to be worked on is conveyed; a first arm attached to the base so as to rotate about a first axis along the vertical direction and extending in a direction away from the first axis; a second arm attached to the first arm so as to rotate about a second axis parallel to the first axis and extending in a direction away from the second axis; a third arm attached to the second arm so as to rotate about a third axis parallel to the first axis and extending in a direction away from the third axis; and a fourth arm attached to the third arm at a tip end of the third arm so as to extend in the vertical direction and move a tool capable of holding a door attached to the vehicle body along the vertical direction. The fourth arm holds the tool in a liftable manner so that it can pass through the window frame of the door. In the vertical direction, the connection point between the third arm and the fourth arm is lower than the uppermost position of the second arm and the third arm. The second arm and the third arm are arranged to operate below the door of a vehicle body being conveyed along the conveyor line. In the vertical direction, at least a part of the tip of the third arm and at least a part of the second arm are positioned at the same height.

[0007] A door opening / closing system according to one aspect of the present disclosure includes the door opening / closing robot, a transport device that transports a vehicle body along a transport line, and a control device that controls the door opening / closing robot to open and close the doors of the vehicle body being transported by the transport device. [Effects of the Invention]

[0008] According to the present disclosure, a door opening / closing robot and a door opening / closing system that are useful for saving space are provided. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an example of a painting system provided with a door opening / closing robot. [Figure 2] FIG. 2 is a side view showing an example of a door opening and closing robot. [Figure 3] FIG. 3 is a top view showing an example of a door opening and closing robot. [Figure 4] FIG. 4 is a schematic diagram showing an example of the internal configuration of the door opening / closing robot and an example of the functional configuration of the control device. [Figure 5] 5(a) and 5(b) are schematic diagrams showing an example of a fourth arm and a tool. [Figure 6] FIG. 6 is a side view schematically showing an example of the height relationship between the workpiece and the door opening / closing robot. [Figure 7] FIG. 7 is a top view schematically showing an example of the installation position of the door opening / closing robot. [Figure 8] FIG. 8 is a side view schematically showing an example of a door opening and closing robot. [Figure 9] FIG. 9 is a side view schematically showing an example of a door opening and closing robot. [Figure 10] FIG. 10 is a block diagram illustrating an example of a hardware configuration of the control device. [Figure 11] FIG. 11 is a flowchart showing an example of a series of processes executed by the control device. [Figure 12]12(a) and 12(b) are schematic diagrams for explaining an example of the operation of the door opening and closing robot. [Figure 13] 13(a) and 13(b) are schematic diagrams for explaining an example of the operation of the door opening and closing robot. [Figure 14] 14(a) and 14(b) are schematic diagrams for explaining an example of the operation of the door opening and closing robot. [Figure 15] 15(a) and 15(b) are schematic diagrams for explaining an example of the operation of the door opening and closing robot. [Figure 16] 16(a) and 16(b) are schematic diagrams for explaining an example of the operation of the door opening and closing robot. [Figure 17] FIG. 17 is a schematic diagram showing an example of a series of operations of a door opening and closing robot. [Figure 18] FIG. 18 is a schematic diagram showing an example of a series of operations of a door opening and closing robot. [Figure 19] FIG. 19 is a schematic diagram showing an example of a series of operations of a door opening and closing robot. [Figure 20] FIG. 20 is a schematic diagram showing an example of a painting system provided with two door opening and closing robots. [Figure 21] FIG. 21 is a flowchart showing an example of a series of processes executed by the control device. [Figure 22] FIG. 22 is a schematic diagram for explaining an example of the operation of the door opening and closing robot. [Figure 23] FIG. 23 is a schematic diagram for explaining an example of the operation of the door opening and closing robot. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment will be described below with reference to the drawings. In the description, the same elements or elements having the same functions are designated by the same reference numerals, and redundant description will be omitted.

[0011] The painting system 1 shown in FIG. 1 is a system for performing at least a part of a painting operation on an object to be painted (hereinafter referred to as "workpiece W"). The workpiece W includes a vehicle body 250 that forms a passenger compartment in an automobile (e.g., a four-wheeled automobile), and doors 260 attached to the vehicle body 250. The workpiece W is in a state before parts such as interior materials, an engine, and windows are attached. The doors 260 (side doors) are attached to the vehicle body 250 (body) so as to be able to be opened and closed freely. In one example, two doors 260 are attached to each of the left and right side surfaces of the vehicle body 250 (both side surfaces of the vehicle body 250).

[0012] The painting system 1 is configured to perform so-called interior panel painting. The areas to be painted by the painting system 1 include areas that need to be painted with the door 260 open. The areas to be painted by the painting system 1 include, for example, the inside of the door 260 and a center pillar located between a pair of doors 260 lined up front and behind. Hereinafter, the door 260 attached to the vehicle body 250 may be referred to as the "door 260 of the vehicle body 250." The door 260 may be a hinged door or a sliding door. Two or more doors 260 provided on one side of the vehicle body 250 may be different types of doors.

[0013] The painting system 1 paints the workpiece W including the vehicle body 250 and the door 260 while opening and closing the door 260 while the vehicle body 250 is being transported in an area for painting work (inside the painting booth). The area for painting work (hereinafter referred to as the "painting area R") is defined by, for example, a booth bottom wall 202, a pair of booth side walls 204, and the booth ceiling. In order to prevent the diffusion of paint mist, the painting system 1 may form a downflow that flows from above to below in the painting area R.

[0014] The painting system 1 includes a transport device 12, a painting robot, a door opening / closing robot 14, and a control device 16. The transport device 12 is configured to transport a vehicle body 250 (workpiece W) along a predetermined transport line Lc. The transport device 12 transports the vehicle body 250 along the transport line Lc while maintaining the vehicle body 250 at a constant vertical height. The transport speed of the transport device 12 may be constant. The transport device 12 may transport the vehicle body 250 with the front portion of the vehicle body 250 facing forward. The transport line Lc is a virtual line set horizontally. As the transport device 12 transports the vehicle body 250 along the transport line Lc, the center of the vehicle body 250 in the width direction moves on the transport line Lc.

[0015] In this disclosure, the horizontal direction in which the conveying line Lc extends is referred to as the "X-axis direction," and the horizontal direction perpendicular to the X-axis direction is referred to as the "Y-axis direction." The X-axis direction corresponds to the longitudinal direction of the painting area R, and the Y-axis direction corresponds to the width direction of the painting area R. In the drawings, the Z-axis direction represents the up-down direction perpendicular to both the X-axis and Y-axis directions. The terms "upstream" and "downstream" are used based on the transport of the vehicle body 250 by the conveying device 12. The conveying device 12 transports the vehicle body 250 from upstream to downstream along the conveying line Lc.

[0016] The conveying device 12 is provided on the booth bottom wall 202 in the coating region R. The conveying device 12 is, for example, a conveyor. The conveying device 12 is disposed between a pair of booth side walls 204 in the Y-axis direction. Each of the pair of booth side walls 204 extends along a conveying line Lc (X-axis direction). The conveying device 12 may be disposed in the center between the pair of booth side walls 204 in the Y-axis direction. In the Y-axis direction, the distance between one of the pair of booth side walls 204 and the conveying line Lc is approximately the same as the distance between the other of the pair of booth side walls 204 and the conveying line Lc. In the present disclosure, the distance between one member and another member is defined as the shortest distance between these members. The booth side wall 204 may include a plurality of supports 208 and a wall main body 206 positioned between adjacent pairs of supports 208.

[0017] The painting robot works in cooperation with the door opening / closing robot 14 to paint the workpiece W being transported by the transport device 12. The painting robot is, for example, a vertical articulated robot with six or more axes. The painting robot may be installed on the booth side wall 204 (for example, on a support or beam of the booth side wall 204). The painting robot is installed so that when the door opening / closing robot 14 opens the door 260, it can paint the area to be painted related to the door 260. The painting robot sprays (atoms) paint from painting guns attached to the tips of multiple arms.

[0018] The door opening / closing robot 14 is disposed between the transport line Lc along which the vehicle body 250 to be worked on is transported and the booth side wall 204. The door opening / closing robot 14 is installed on the bottom surface of the booth bottom wall 202 located between the side of the vehicle body 250 being transported along the transport line Lc and the booth side wall 204, or on the booth side wall 204. The door opening / closing robot 14 is a horizontal articulated robot (a so-called SCARA robot). The door opening / closing robot 14 is configured to be able to open and close a door 260 attached to the vehicle body 250.

[0019] 2 and 3 show an example of the door opening / closing robot 14. The door opening / closing robot 14 includes a base 20, a first arm 30, a second arm 40, a third arm 50, a fourth arm 60, and a tool 70.

[0020] The base 20 is a base portion that fixes the door opening / closing robot 14 to a predetermined position and supports multiple arms. The base 20 is provided at a position different from the conveyance line Lc. The base 20 is provided in the Y-axis direction between the booth side wall 204 and the vehicle body 250 (the side of the vehicle body 250 facing the booth side wall 204) being conveyed along the conveyance line Lc. The base 20 is provided in the X-axis direction within a range in which the vehicle body 250 is conveyed by the conveyance device 12. The conveyance device 12 conveys the vehicle body 250 from a position upstream of the base 20 on the conveyance line Lc to a position downstream of the base 20. In one example, the conveyance device 12 conveys the vehicle body 250 from a first predetermined position where the front end of the vehicle body 250 is located upstream of the base 20 to a second predetermined position where the rear end of the vehicle body 250 is located downstream of the base 20.

[0021] The base 20 is fixed to the booth bottom wall 202 or the booth side wall 204. By fixing the base 20 in a predetermined position, the door opening / closing robot 14 (base 20) is fixed in the painting area R. Even when the workpiece W is transported by the transport device 12, the position of the base 20 in the painting area R does not change. In the painting system 1, no device is provided for transporting the door opening / closing robot 14 itself.

[0022] The base 20 may be attachable at its bottom surface 22 and one side surface (for example, side surface 24b described below) to a predetermined position. When the bottom surface 22 is attached, the base 20 is fixed to the booth bottom wall 202. When the side surface of the base 20 is attached, the base 20 is fixed to the booth side wall 204. By making the bottom surface 22 and side surface of the base 20 attachable, it is possible to select between fixing the bottom surface of the base 20 to the booth bottom wall 202 and fixing the side surface of the base 20 to the booth side wall 204.

[0023] The base 20 may be fixed to the booth bottom wall 202 or the booth side wall 204 via another member. When the base 20 is fixed to the booth bottom wall 202, a fixing member may be provided between the booth bottom wall 202 and the base 20, and when the base 20 is fixed to the booth side wall 204, a fixing member may be provided between the booth side wall 204 and the base 20. Fixing the base 20 to the booth bottom wall 202 or the booth side wall 204 also includes the case where the base 20 is substantially fixed via another member.

[0024] The base 20 includes, for example, a mounting portion 26 provided on the bottom surface 22 and a mounting portion 28 provided on a side surface. In one example, the mounting portion 26 is fixed to a booth bottom wall 202 by a fixing member such as a bolt, or the mounting portion 28 is fixed to a booth side wall 204 by a fixing member such as a bolt. In the example shown in FIG. 1 , the bottom surface 22 of the base 20 is attached to the booth bottom wall 202 located between a vehicle body 250 being transported along the transport line Lc and the booth side wall 204 that forms the painting area R.

[0025] The first arm 30 is attached to the base 20 so as to rotate around a rotation axis Ax1 (first axis) along the vertical direction. The rotation axis Ax1 is a vertical axis extending in the vertical direction, and the first arm 30 is rotatable around the rotation axis Ax1. The first arm 30 extends in a direction away from the rotation axis Ax1. The first arm 30 (the arm main body of the first arm 30) extends in a direction intersecting the rotation axis Ax1 (for example, a direction perpendicular to the rotation axis Ax1). A base end 32 of the first arm 30 may be attached to the base 20. The rotation axis Ax1 may pass through the base end 32 and the base 20. The base end 32 of the first arm 30 may be attached on the base 20.

[0026] The second arm 40 is attached to the first arm 30 so as to rotate around a rotation axis Ax2 (second axis) parallel to the rotation axis Ax1. "Parallel" does not only mean strictly parallel, but also includes substantially parallel, allowing for manufacturing or installation errors. The same applies to "vertical" and "plumb," and includes substantially perpendicular and substantially plumb. The rotation axis Ax2 is a vertical axis extending in the up-down direction, and the second arm 40 is rotatable around the rotation axis Ax2.

[0027] The second arm 40 extends in a direction away from the rotation axis Ax2. The second arm 40 (the arm body of the second arm 40) extends in a direction intersecting the rotation axis Ax2 (for example, a direction perpendicular to the rotation axis Ax2). The base end 42 of the second arm 40 may be attached to the tip end 34 of the first arm 30. The rotation axis Ax2 may pass through the base end 42 of the second arm 40 and the tip end 34 of the first arm 30. The second arm 40 (for example, the base end 42) may be attached below the tip end 34 of the first arm 30.

[0028] The third arm 50 is attached to the second arm 40 so as to rotate around a rotation axis Ax3 (third axis) parallel to the rotation axis Ax1. The rotation axis Ax3 is a vertical axis extending in the up-down direction, and the second arm 40 is rotatable around the rotation axis Ax3. The third arm 50 extends in a direction away from the rotation axis Ax3. The third arm 50 (the arm main body of the third arm 50) extends in a direction intersecting the rotation axis Ax3. When viewed in the up-down direction, the third arm 50 is formed to extend in one horizontal direction. A base end 52 of the third arm 50 may be attached to the tip end 44 of the second arm 40. The rotation axis Ax3 may pass through the base end 52 of the third arm 50 and the tip end 44 of the second arm 40. The third arm 50 (for example, the base end 52) may be attached above the tip end 44 of the second arm 40.

[0029] The fourth arm 60 is attached to the third arm 50 so as to extend in the vertical direction. The fourth arm 60 is attached to a tip 54 of the third arm 50. The fourth arm 60 moves a tool 70, which is capable of holding a door 260 attached to the vehicle body 250, in the vertical direction. The tool 70 is attached to the fourth arm 60. The fourth arm 60 may be attached to the tip 54 of the third arm 50 so as to rotate together with the tool 70 around a rotation axis Ax4 (fourth axis) parallel to the rotation axis Ax1.

[0030] The rotation axis Ax4 is a vertical axis extending in the up-down direction, and the fourth arm 60 is rotatable around the rotation axis Ax4. As the fourth arm 60 rotates around the rotation axis Ax4, the tool 70 also rotates around the rotation axis Ax4. Details of the fourth arm 60 and the tool 70 will be described later.

[0031] In FIG. 2, the height position of the booth bottom wall 202 is indicated by "H0", the height position of the lower end of the body 250 of the workpiece W being transported by the transport device 12 is indicated by "H1", and the height position of the lower end of the door 260 of the workpiece W is indicated by "H2". In this disclosure, height position means a position in the vertical direction. "High" and "low" represent the positional relationship of positions in the vertical direction (height position). The height position of each arm will be explained below.

[0032] At least a portion of a connecting portion (hereinafter referred to as "connecting portion CS") including the tip end 44 of the second arm 40 and the base end 52 of the third arm 50 is located at the same height as at least a portion of the base 20. For example, at least a portion of the connecting portion CS and the uppermost position of the base 20 are located at the same height. In this case, the lowermost position of the base 20 does not have to be at the same height as the connecting portion CS. The lowermost position of the connecting portion CS may be higher than the lowermost position of the base 20. The uppermost position of a member refers to the uppermost position of that member, and the lowermost position of a member refers to the lowermost position of that member. At least a portion of the tip end 44 of the second arm 40 may be located at the same height as at least a portion of the base 20, and at least a portion of the base end 52 of the third arm 50 may be located at the same height as at least a portion of the base 20.

[0033] Unlike the example shown in FIG. 2 , at least a portion of the connecting portion CS and the lowest position of the base 20 may be located at the same height, and the highest position of the base 20 may not be at the same height as the connecting portion CS. Alternatively, the highest position of the base 20 may be located at the same height as at least a portion of the connecting portion CS, and the lowest position of the base 20 may be located at the same height as at least a portion of the connecting portion CS. Alternatively, at least a portion of the tip end 44 of the second arm 40 may be located at the same height as at least a portion of the base 20, and the base end 52 of the third arm 50 may not be at the same height as the base 20. Alternatively, at least a portion of the base end 52 of the third arm 50 may be located at the same height as at least a portion of the base 20, and at least a portion of the tip end 44 of the second arm 40 may not be at the same height as the base 20.

[0034] The second arm 40 and the third arm 50 may be provided to operate below the door 260 held by the tool 70. Operating below the door 260 means operating at a position lower than the lower end of the door 260, and may operate in an area including the vertically below the door 260, or may operate in an area different from the horizontal position of the door 260. The second arm 40 and the third arm 50 may be installed at a height position that allows them to operate at a position lower than the lower end of the door 260. The uppermost position h1 of the third arm 50 may be lower than the height position H2 of the lower end of the door 260 (the lowermost position of the door 260). The uppermost position h2 of the second arm 40 may be lower than the height position H2. When the second arm 40 and the third arm 50 are moved to a position where they overlap with the door 260 as viewed from the up-down direction, the second arm 40 and the third arm 50 may be positioned below the door 260.

[0035] The second arm 40 and the third arm 50 may be provided to operate below the vehicle body 250 being transported along the transport line Lc. The second arm 40 and the third arm 50 may be installed at a height position that allows them to operate at a position lower than the lower end of the vehicle body 250. The uppermost position h1 of the third arm 50 may be lower than the height position H1 of the lower end of the vehicle body 250 (the lowermost position of the vehicle body 250). The uppermost position h2 of the second arm 40 may be lower than the height position H1 of the lower end of the vehicle body 250. When the second arm 40 and the third arm 50 are moved to a position that overlaps with the vehicle body 250 as viewed in the vertical direction, the second arm 40 and the third arm 50 may be able to be positioned below the vehicle body 250.

[0036] The uppermost position of the portion of the second arm 40 other than the tip end 44 and the uppermost position h3 of the portion of the third arm 50 other than the base end 52 are lower than the uppermost position of the coupling part CS. In the example shown in FIG. 1 , the uppermost position of the coupling part CS corresponds to the uppermost position h1 of the third arm 50, and the uppermost position of the portion of the second arm 40 other than the tip end 44 corresponds to the uppermost position h2 of the second arm 40. As described above, the coupling part CS may be the highest part of the second arm 40 and the third arm 50.

[0037] The connection point CP12 between the first arm 30 and the second arm 40 and at least a part of the coupling part CS may be located at the same height. The connection point CP12 may be lower than the uppermost position (uppermost position h1) of the coupling part CS and higher than the lowermost position of the coupling part CS. The connection point CP12 is the point on the first arm 30 where the second arm 40 is connected (the point where the second arm 40 is supported by the first arm 30).

[0038] The connection point CP34 between the third arm 50 and the fourth arm 60 may be lower than the uppermost position of the second arm 40 and the third arm 50. The connection point CP34 is the point on the third arm 50 where the fourth arm 60 is connected (the point where the fourth arm 60 is supported by the third arm 50). The uppermost position of the second arm 40 and the third arm 50 means the uppermost position of a portion including both the second arm 40 and the third arm 50. In the example shown in FIG. 2 , the uppermost position of the second arm 40 and the third arm 50 corresponds to the uppermost position h1 of the third arm 50.

[0039] At least a portion of the tip 54 of the third arm 50 and at least a portion of the second arm 40 may be located at the same height. For example, the lowest position h6 of the second arm 40 may be located at the same height as at least a portion of the tip 54 of the third arm 50. The lowest position of the tip 54 of the third arm 50 may be located at the same height as at least a portion of the second arm 40.

[0040] The tip end 54 of the third arm 50 may be lower than the base end 52. The uppermost position of the tip end 54 may be lower than the uppermost position (uppermost position h1) of the base end 52. At least a part of an intermediate portion 56 of the third arm 50 between the base end 52 and the tip end 54 may extend diagonally downward vertically from the base end 52. The uppermost position h2 of the second arm 40 may be lower than the uppermost position h8 of the underside of the intermediate portion 36 of the first arm 30 between the base end 32 and the tip end 34.

[0041] At least a portion of the second arm 40 and at least a portion of the base 20 may be located at the same height. The lowest position h6 of the second arm 40 may be located at the same height as at least a portion of the base 20. At least a portion of the base end 42 of the second arm 40 may be located at the same height as at least a portion of the base 20. At least a portion of an intermediate portion 46 between the base end 42 and the tip end 44 of the second arm 40 may be located at the same height as at least a portion of the base 20.

[0042] At least a portion of the third arm 50 and at least a portion of the base 20 may be located at the same height. The lowest position h7 of the third arm 50 may be located at the same height as at least a portion of the base 20. At least a portion of the tip 54 of the third arm 50 may be located at the same height as at least a portion of the base 20. At least a portion of the intermediate portion 56 of the third arm 50 may be located at the same height as at least a portion of the base 20.

[0043] The uppermost position h4 of the tip end 34 of the first arm 30 may be lower than the height position H2 (the lowest position of the door 260) of the lower end of the door 260 of the vehicle body 250 being transported along the transport line Lc. The uppermost position h4 may be higher than the height position H2 (the lowest position of the vehicle body 250) of the lower end of the vehicle body 250 being transported along the transport line Lc. At least a portion of the base end 32 of the first arm 30 may be located at the same height as the lowest position (height position H1) of the door 260 of the vehicle body 250 being transported along the transport line Lc. The uppermost position h5 of the first arm 30 may be higher than the height position H1. The uppermost position h5 of the first arm 30 may be higher than the height position H2.

[0044] The uppermost position h2 of the second arm 40 and the uppermost position h1 of the third arm 50 may be lower than the uppermost position h4 of the tip end 34 of the first arm 30. The uppermost position h2 of the second arm 40 and the uppermost position h1 of the third arm 50 may be lower than the uppermost position h5 of the first arm 30.

[0045] The lowest position h6 of the second arm 40 and the lowest position h7 of the third arm 50 are higher than the booth bottom wall 202. The lowest position h6 is higher than the height position H0, and the lowest position h7 is higher than the height position H0. The second arm 40 and the third arm 50 may operate in a region between a bottom wall portion of the booth bottom wall 202 between the car body 250 on the transfer line Lc and the booth side wall 204, and a horizontal imaginary plane at the height position H2 (see FIG. 6).

[0046] The lowest position h6 of the second arm 40 and the lowest position h7 of the third arm 50 may be approximately aligned with each other in the vertical direction. When the lowest position h6 and the lowest position h7 are approximately aligned with each other in the vertical direction, the difference in the vertical direction between the lowest position h6 and the lowest position h7 is 200 mm or less. The difference in the vertical direction between the lowest position h6 and the lowest position h7 may be 150 mm or less, 130 mm or less, or 100 mm or less. The lowest positions h6 and h7 may be set so that the difference in the vertical direction between the lowest position h6 and the lowest position h7 is relatively small compared to the arm length (described below) of each arm.

[0047] 3, at least one of the side portions 43, 43 of the second arm 40 may be formed to be concave (curved) inward. Each of the two side portions 43 of the second arm 40 may be formed to be concave inward. In the second arm 40, the side surface of an intermediate portion 46 between the base end portion 42 and the tip end portion 44 may be located inside an imaginary plane connecting the side surface of the base end portion 42 and the side surface of the tip end portion 44.

[0048] 3 shows the door opening / closing robot 14 in a state in which the rotation axes Ax1, Ax2, Ax3, and Ax4 are aligned on a straight imaginary line. When viewed from above and below, the imaginary line passing through the rotation axes Ax1, Ax2, Ax3, and Ax4 is defined as a center line CL. The door opening / closing robot 14 (more specifically, the portion of the door opening / closing robot 14 other than the tool 70) may be substantially symmetrical with respect to the center line CL.

[0049] 4 shows a schematic diagram of the interior of the door opening / closing robot 14. The pressure in at least a part of the interior of the door opening / closing robot 14 may be higher than the pressure in the area outside the door opening / closing robot 14. This reduces the possibility of paint mist entering the interior of the door opening / closing robot 14. Wiring for supplying power to the motors and wiring for transmitting signals between various sensors may be provided inside the door opening / closing robot 14. The door opening / closing robot 14 has motors M1 to M5 and driving devices 91 to 95.

[0050] The motor M1 (first motor) generates a driving force (first driving force) for rotating the first arm 30 about the rotation axis Ax1. The motor M1 may be disposed on the first arm 30. The motor M1 includes a motor main body 81a (first motor main body) and an output shaft 81b (first output shaft). The motor M1 is attached to the first arm 30 from above with the output shaft 81b facing downward. With the motor M1 attached, the motor main body 81a may be located vertically above the output shaft 81b. The motor M1 may be detachably attached to the arm main body of the first arm 30.

[0051] The motor M1 may be disposed between the rotation axis Ax1 and the rotation axis Ax2 and closer to the rotation axis Ax1. The distance between the motor M1 and the rotation axis Ax1 may be smaller than the distance between the motor M1 and the rotation axis Ax2. The driving device 91 transmits the driving force of the motor M1 to a first joint between the base 20 and the base end 32 of the first arm 30 to operate the first joint. The driving device 91 includes, for example, a gear and a reducer. The driving device 91 may include a belt and a pulley. The driving device 91 may be disposed on the first arm 30.

[0052] The motor M2 (second motor) generates a driving force (second driving force) for rotating the second arm 40 about the rotation axis Ax2. The motor M2 may be disposed on the first arm 30. The motor M2 includes a motor main body 82a (second motor main body) and an output shaft 82b (second output shaft). The motor M2 is attached to the first arm 30 from above with the output shaft 82b facing downward. With the motor M2 attached, the motor main body 82a may be located vertically above the output shaft 82b. The motor M2 may be detachably attached to the arm main body of the first arm 30.

[0053] The motor M2 may be disposed between the rotation axis Ax1 and the rotation axis Ax2 and closer to the rotation axis Ax1. The distance between the motor M2 and the rotation axis Ax1 may be smaller than the distance between the motor M2 and the rotation axis Ax2. The drive unit 92 transmits the drive force of the motor M2 to a second joint between the tip end 34 of the first arm 30 and the base end 42 of the second arm 40 to operate the second joint. The drive unit 92 includes, for example, a belt, a pulley, a gear, and a reducer. The drive unit 92 may be disposed on the first arm 30.

[0054] In the first arm 30, the rotation axis Ax1, the motor M1, the motor M2, and the rotation axis Ax2 may be arranged in this order. The first arm 30 may include a cover member 38 that covers the attached motors M1 and M2 from above. The cover member 38 is detachably provided on the arm body of the first arm 30. The cover member 38 is arranged between the rotation axis Ax1 and the rotation axis Ax2, closer to the rotation axis Ax1.

[0055] The motor M3 (third motor) generates a driving force (third driving force) for rotating the third arm 50 about the rotation axis Ax3. The motor M3 may be disposed on the second arm 40. The motor M3 includes a motor main body 83a (third motor main body) and an output shaft 83b (third output shaft). The motor M3 is attached to the second arm 40 from above with the output shaft 83b facing downward. With the motor M3 attached, the motor main body 83a may be located vertically above the output shaft 83b. The motor M3 may be detachably attached to the arm main body of the second arm 40.

[0056] The motor M3 may be disposed between the rotation axis Ax2 and the rotation axis Ax3 and closer to the rotation axis Ax2. The motor M3 may be disposed on the second arm 40 such that the distance between the motor M3 and the rotation axis Ax2 is smaller than the distance between the motor M3 and the rotation axis Ax3. The drive unit 93 transmits the drive force of the motor M3 to a third joint between the tip end 44 of the second arm 40 and the base end 52 of the third arm 50 to operate the third joint. The drive unit 93 includes, for example, a belt, a pulley, a gear, and a reducer. The drive unit 93 may be disposed on the second arm 40.

[0057] The second arm 40 may include a cover member 48 that covers the attached motor M3 from above. The cover member 48 is detachably provided on the arm body of the second arm 40. The cover member 48 may be disposed between the rotation axis Ax2 and the rotation axis Ax3, closer to the rotation axis Ax2.

[0058] The motor M4 (fourth motor) generates a driving force (fourth driving force) for rotating the fourth arm 60 about the rotation axis Ax4. The motor M4 may be disposed on the third arm 50. The motor M4 includes a motor main body 84a (fourth motor main body) and an output shaft 84b (fourth output shaft). The motor M4 is attached to the third arm 50 from above with the output shaft 84b facing downward. With the motor M4 attached, the motor main body 84a may be located vertically above the output shaft 84b. The motor M4 may be detachably attached to the arm main body of the third arm 50.

[0059] The motor M4 may be disposed in a middle portion 56 between the base end 52 and the tip end 54 of the third arm 50, at a position lower than the base end 52. The drive unit 94 transmits the drive force of the motor M4 to a fourth joint between the tip end 54 of the third arm 50 and the lower end of the fourth arm 60, thereby operating the fourth joint. The drive unit 94 includes, for example, a belt, a pulley, a gear, and a reducer. The drive unit 94 may be disposed in the fourth arm 60.

[0060] The motor M5 (fifth motor) generates a driving force (fifth driving force) for moving the tool 70 in the up-down direction. The motor M5 may be disposed on the third arm 50. The motor M5 includes a motor body 85a (fifth motor body) and an output shaft 85b (fifth output shaft). The motor M5 is attached to the third arm 50 from above with the output shaft 85b facing downward. With the motor M5 attached, the motor body 85a may be located vertically above the output shaft 85b. The motor M5 may be detachably attached to the arm body of the third arm 50.

[0061] The motor M5 may be disposed in a position lower than the base end 52 in the intermediate portion 56 of the third arm 50. The drive device 95 is included in the fourth arm 60, and raises and lowers the portion supporting the tool 70 by the drive force generated by the motor M5. The drive device 95 includes a transmission device 96 and an elevating device 97. The transmission device 96 transmits the drive force of the motor M5 to the elevating device 97. The elevating device 97 is, for example, a ball screw, and converts the drive force (rotational force) of the motor M5 transmitted via the transmission device 96 into linear motion. The elevating device 97 is disposed in the fourth arm 60 (inside the fourth arm 60).

[0062] At least a portion of motor M4 and at least a portion of motor M5 are disposed in a dead space formed above the intermediate portion 56 and below the uppermost position of the base end 52 due to the tip end 54 being lower than the base end 52. The third arm 50 may include a cover member 58 that covers the attached motors M4 and M5 from above. The cover member 58 is detachably provided on the arm body of the third arm 50. The fourth arm 60 may not have any motors (drive sources) disposed therein.

[0063] The arm length L1 of the first arm 30, the arm length L2 of the second arm 40, and the arm length L3 of the third arm 50 may be approximately the same as one another. The arm length L1 is the distance between the rotation axis Ax1 and the rotation axis Ax2. The arm length L2 is the distance between the rotation axis Ax2 and the rotation axis Ax3. The arm length L3 is the distance between the rotation axis Ax3 and the rotation axis Ax4.

[0064] The arm length L2 of the second arm 40 may be 0.9 to 1.1 times the arm length L1 of the first arm 30, 0.95 to 1.05 times the arm length L1, or 0.98 to 1.02 times the arm length L1. The arm length L3 of the third arm 50 may be 0.9 to 1.1 times the arm length L1 of the first arm 30, 0.95 to 1.05 times the arm length L1, or 0.98 to 1.02 times the arm length L1.

[0065] The door opening / closing robot 14 keeps the door 260 open while following the movement of the vehicle body 250 while it is being transported. When the distance Lx, the distance Ly, and the total arm length Lt are defined as follows (see also FIG. 1), the total arm length Lt may be set to satisfy the following formula (1): Distance Lx: distance traveled by the vehicle body 250 (center pillar) during the entire period in which the door 260 is opened by the door opening / closing robot 14 Distance Ly: distance in the Y-axis direction between the rotation axis Ax1 and a line passing through the side of the vehicle body 250 on which the door 260 is located Total arm length Lt: The sum of arm length L1, arm length L2, and arm length L3

number

[0066] For example, when the distance Lx is 4000 mm and the distance Ly is 1200 mm, the total arm length Lt is set to 2330 mm or more. The total arm length Lt may be approximately 2400 mm to 2700 mm. Each of the arm lengths L1, L2, and L3 (each arm length) may be approximately 800 mm to 900 mm.

[0067] 5(a) and 5(b) show the operation of the fourth arm 60 and the tool 70. The fourth arm 60 holds the tool 70 so that it can be raised and lowered so that the tool 70 can pass through the window frame 262 (the opening inside the window frame 262) of the door 260. The fourth arm 60, which is provided with the lifting device 97, can raise and lower the tool 70 to a height position where at least a portion of the tool 70 can pass through the window frame 262.

[0068] The fourth arm 60 includes, for example, a fixed portion 62 (first portion), a movable portion 64 (second portion), and a cover portion 68. The fixed portion 62 is attached to the tip portion 54 of the third arm 50 and is rotatable around a rotation axis Ax4. The fixed portion 62 is formed to extend in the vertical direction and includes, for example, a housing that houses an elevator device 97 and a portion of the movable portion 64. The movable portion 64 is rotatable together with the fixed portion 62 around the rotation axis Ax4 as the fixed portion 62 rotates, and is provided on the fixed portion 62 so as to be movable up and down. The tool 70 is attached to the movable portion 64.

[0069] The tool 70 attached to the movable part 64 moves up and down as the position of the movable part 64 changes relative to the fixed part 62 in the vertical direction. The movable part 64 includes, for example, a tool holding part 64a and a connecting part 64b. The tool holding part 64a is formed in a rod shape so as to extend in the vertical direction. When viewed from the vertical direction, the center of the tool holding part 64a substantially coincides with the rotation axis Ax4. The upper end part of the tool holding part 64a is exposed to the outside of the fixed part 62. The tool 70 is attached to the upper end part of the tool holding part 64a. The connecting part 64b connects the tool holding part 64a to a movable part of the lifting device 97 (for example, a nut of a ball screw).

[0070] The cover portion 68 is formed to cover at least a portion of the fixed portion 62 from above. At least a portion of the cover portion 68 covers the top and side surfaces of the upper end portion of the fixed portion 62. The cover portion 68 is attached to the tool holding portion 64a of the movable portion 64, and moves up and down together with the movable portion 64. The cover portion 68 may be formed so as to be able to maintain a state in which it covers a portion of the fixed portion 62 within a range in which the movable portion 64 can move up and down.

[0071] The tool 70 is configured to be able to pass through the window frame 262 of the door 260 (the opening in the window frame 262) and to hold the inside of the door 260. The tool 70 includes, for example, an extension portion 72 and a holding portion 74. The extension portion 72 is formed to extend in a direction intersecting the up-down direction. The extension portion 72 may extend linearly or curvedly along the intersecting direction. For example, the lower end of the extension portion 72 is connected to the upper end of the tool holding portion 64a, and extends horizontally from the connection point between the extension portion 72 and the tool holding portion 64a.

[0072] The holding portion 74 is connected to the extension portion 72 and can contact the inner surface 264 of the door 260. The holding portion 74 extends downward from the extension portion 72, starting from the connection point between the extension portion 72 and the holding portion 74. The holding portion 74 is connected, for example, to a lower end of the extension portion 72 that is far from the rotation axis Ax4. The holding portion 74 may hold the door 260 by attracting the inner surface 264 of the door 260 with magnetic force. The holding portion 74 may include a permanent magnet and may be formed in a cylindrical shape. The holding portion 74 may be configured to be rotatable about an axis that passes through its center and along its extension direction.

[0073] 5(a), the tool 70 is located below the height position H3 of the lower end of the window frame 262 of the door 260. The lifting device 97, to which the driving force of the motor M5 is transmitted, raises the tool holding portion 64a and the connecting portion 64b, thereby raising the tool 70. As shown in FIG. 5(b), the tool 70 rises until the lower end of the holding portion 74 is higher than the height position H3 of the lower end of the window frame 262, thereby allowing the tool 70 to pass through the window frame 262.

[0074] With the open area in the window frame 262 and the holding portion 74 facing each other, the door opening / closing robot 14 operates each arm so that the rotation axis Ax4 approaches the door 260, thereby moving a part of the tool 70 (the holding portion 74) to the inside of the door 260. Then, the fourth arm 60, to which the lifting device 97 is attached, lowers the tool 70 so that the holding portion 74 contacts the inner surface 264 of the door 260. As described above, the fourth arm 60 moves the tool 70 in the vertical direction so that the extension portion 72 can pass through the window frame 262 in a state where it is elevated higher than the lower end of the window frame 262 of the door 260.

[0075] With the holding portion 74 in contact with the inner surface 264 of the door 260 in the closed state, the door opening / closing robot 14 operates each arm to open the door 260. While the workpiece W is being transported along the transport line Lc, the door opening / closing robot 14 operates each arm to maintain the state in which the holding portion 74 is in contact with the inner surface 264 of the door 260, while maintaining the open state of the door 260. With the holding portion 74 in contact with the inner surface 264 of the door 260 in the open state, the door opening / closing robot 14 operates each arm to close the door 260. Figure 6 schematically shows a state in which the holding portion 74 of the tool 70 holds the door 260 and the door 260 is open.

[0076] FIG. 7 schematically shows a portion of the door opening / closing robot 14 located between the booth side wall 204 and the conveying line Lc. The base 20 may include a portion formed in a rectangular parallelepiped shape. As shown in FIG. 7, when viewed from the top-bottom direction (viewing the booth bottom wall 202 from above), the portion of the base 20 includes four side surfaces. The base 20 may be installed so that the four side surfaces are aligned along the X-axis direction or the Y-axis direction. Of the pair of side surfaces aligned along the X-axis direction, the side surface (front surface) closer to the conveying line Lc is referred to as "side surface 24a," and the side surface (rear surface) closer to the booth side wall 204 is referred to as "side surface 24b." The pair of side surfaces aligned along the Y-axis direction are referred to as "side surface 24c" and "side surface 24d," respectively.

[0077] The base 20 may be installed so that the side surface having the shortest distance from the rotation axis Ax1 faces the conveyor line Lc when viewed from above. In the example shown in FIG. 7, the distance between the side surface 24a and the rotation axis Ax1 is shorter than the distance between the side surface 24b and the rotation axis Ax1, the distance between the side surface 24c and the rotation axis Ax1, and the distance between the side surface 24d and the rotation axis Ax1. The distance between the side surface 24a and the rotation axis Ax1 and the distance between the side surface 24b and the rotation axis Ax1 may be substantially the same. Even in this case, since the side surface 24a is included among the sides having the shortest distance from the rotation axis Ax1, the side surface having the shortest distance from the rotation axis Ax1 faces the conveyor line Lc.

[0078] The base 20 (rotation axis Ax1) is disposed between the booth side wall 204 and the side surface of the vehicle body 250 being transported along the transport line Lc, closer to the booth side wall 204. A distance d1 in the Y-axis direction between the booth side wall 204 and the rotation axis Ax1 is smaller than a distance d2 in the Y-axis direction between the rotation axis Ax1 and the transport line Lc. The distance d1 may be ¼ or less, ⅕ or less, or ⅙ or less, of the sum of the distances d1 and d2. For example, when the sum of the distances d1 and d2 is 2500 mm to 3000 mm, the distance d1 may be 600 mm or less, 550 mm or less, or 500 mm or less.

[0079] The base 20 may be arranged so that when the first arm 30 is rotated around the rotation axis Ax1, the tip 34 of the first arm 30 does not overlap the vehicle body 250 when viewed from the top-bottom direction. The position of the base 20 (rotation axis Ax1) may be set so that when a part of the vehicle body 250 is arranged at the same position as the base 20 in the X-axis direction, the tip 34 is not positioned below the vehicle body 250 by the rotation of the first arm 30, or does not come into contact with the vehicle body 250 (workpiece W with the door 260 closed). In FIG. 7 , the rotation trajectory of the tip of the tip 34 is indicated by "IC," and the base 20 may be provided so that the rotation trajectory IC does not overlap with the movement trajectory of the vehicle body 250 due to transport by the transport device 12.

[0080] The above-described configuration of the door opening / closing robot 14 is an example and can be modified as appropriate. As shown in Fig. 8, the base 20 may be attached to (or fixed to) a support 208 included in a booth side wall 204 instead of the booth bottom wall 202.

[0081] 8, the door opening / closing robot 14 may have a second arm 40A instead of the second arm 40, and a third arm 50A instead of the third arm 50. The second arm 40A is attached below the tip end 34 of the first arm 30 and extends away from the rotation axis Ax2. A base end 42A of the second arm 40A may be attached below the tip end 34 of the first arm 30. The third arm 50A is attached below the tip end 44A of the second arm 40A and extends away from the rotation axis Ax3. A base end 52A of the third arm 50A may be attached below the tip end 44A of the second arm 40A.

[0082] The tip end 44A of the second arm 40A may be higher than the base end 42A of the second arm 40A. The uppermost position of the tip end 44A may be higher than the uppermost position of the base end 42A. In the joint CS of the door opening / closing robot 14 shown in FIG. 2, the base end 52 of the third arm 50 is positioned vertically above the base end 42 of the second arm 40. In contrast, in the joint (hereinafter referred to as "joint CSA") including the tip end 44A of the second arm 40A and the base end 52A of the third arm 50A, the tip end 44A is positioned vertically above the base end 52A.

[0083] At least a portion of the connecting portion CSA and at least a portion of the base 20 are located at the same height. For example, at least a portion of the connecting portion CSA and the uppermost position of the base 20 are located at the same height. As with the door opening / closing robot 14 shown in FIG. 2, the connection point between the third arm 50A and the fourth arm 60 may be lower than the uppermost positions of the second arm 40A and the third arm 50A. At least a portion of the tip 54A of the third arm 50A and at least a portion of the second arm 40A may be located at the same height.

[0084] In the door opening and closing robot 14 having the second arm 40A and the third arm 50A, the mutual height relationship between each arm and the workpiece W may be the same as the corresponding height relationship in the door opening and closing robot 14 shown in Fig. 2. In the door opening and closing robot 14 having the second arm 40A and the third arm 50A, the mutual height relationship between the arms may be the same as the corresponding height relationship in the door opening and closing robot 14 shown in Fig. 2.

[0085] As shown in FIG. 9, the door opening / closing robot 14 may have a first arm 30B instead of the first arm 30, a second arm 40B instead of the second arm 40, and a third arm 50B instead of the third arm 50. A base end 32B of the first arm 30B is attached to the base 20 and extends away from the rotation axis Ax1. The base end 32B of the first arm 30B may be attached on the base 20. A tip end 34B of the first arm 30B may be lower than the base end 32B of the first arm 30B. The uppermost position of the tip end 34B may be lower than the uppermost position of the base end 32B.

[0086] The second arm 40B is attached above the tip end 34B of the first arm 30B and extends away from the rotation axis Ax2. A base end 42B of the second arm 40B may be attached above the tip end 34B of the first arm 30B. The third arm 50B is attached below the tip end 44B of the second arm 40B and extends away from the rotation axis Ax3. A base end 52B of the third arm 50B may be attached below the tip end 44B of the second arm 40B.

[0087] At least a portion of a connecting portion (hereinafter referred to as "connecting portion CSB") including the tip end 44B of the second arm 40B and the base end 52B of the third arm 50B and at least a portion of the base 20 are located at the same height. For example, at least a portion of the connecting portion CSB and the uppermost position of the base 20 are located at the same height. As with the door opening / closing robot 14 shown in FIG. 2, the connection point between the third arm 50B and the fourth arm 60 may be lower than the uppermost positions of the second arm 40B and the third arm 50B. At least a portion of the tip end 54B of the third arm 50B and at least a portion of the first arm 30B may be located at the same height.

[0088] In the door opening / closing robot 14 having the first arm 30B, the second arm 40B, and the third arm 50B, the mutual height relationships between each arm and the workpiece W may be the same as the corresponding height relationships in the door opening / closing robot 14 shown in Fig. 2. In the door opening / closing robot 14 having the first arm 30B, the second arm 40B, and the third arm 50B, the mutual height relationships between the arms may be the same as the corresponding height relationships in the door opening / closing robot 14 shown in Fig. 2.

[0089] The base ends 32, 32B of the first arms 30, 30B may be attached to the base 20 at a location other than above the base 20. The base ends 32, 32B of the first arms 30, 30B may be attached below a portion of the base 20 that protrudes from the main body. The base ends 32, 32B of the first arms 30, 30B may be attached to the base 20 so as to be sandwiched between a pair of portions that protrude from the main body of the base 20 from above and below. When the base 20 is fixed to the booth side wall 204, the base ends 32, 32B of the first arms 30, 30B may be attached below the base 20. Some components included in the door opening / closing robot 14 shown in any of Figures 2, 8, and 9 may be applied to the door opening / closing robot 14 shown in the other figures.

[0090] Returning to FIG. 1, the control device 16 is a computer device configured to control the door opening / closing robot 14 described above. In the painting system 1, the transport device 12, the door opening / closing robot 14, and the control device 16 configure a door opening / closing system 10. That is, the painting system 1 is equipped with the door opening / closing system 10. The door opening / closing system 10 opens and closes a door 260 of the workpiece W and maintains the door 260 in an open state while transporting the workpiece W along the transport line Lc so that the painting robot can perform painting work. In the following, an example will be described in which the door 260 is a hinged door and the control device 16 controls the door opening / closing robot 14 shown in FIG. 2.

[0091] The control device 16 is configured to control the door opening / closing robot 14 so that the tool 70 opens the door 260 upstream of the rotation axis Ax1 on the transfer line Lc. The control device 16 is also configured to control the door opening / closing robot 14 so that the door 260 is maintained in an open state while the vehicle body 250 is being transferred along the transfer line Lc, and to control the door opening / closing robot 14 so that the tool 70 closes the door 260 downstream of the rotation axis Ax1 on the transfer line Lc.

[0092] As shown in Fig. 4, the control device 16 has, as functional components (hereinafter referred to as "functional modules"), for example, a conveyance information acquisition unit 102, a door opening control unit 104, a door following control unit 106, and a door closing control unit 108. The processes executed by these functional modules correspond to the processes executed by the control device 16. The door opening / closing robot 14 and the control device 16 constitute a robot device 18. In other words, the painting system 1 is equipped with the robot device 18.

[0093] The transport information acquisition unit 102 acquires information indicating the position on the transport line Lc of the vehicle body 250 being transported by the transport device 12. The transport information acquisition unit 102 may repeatedly acquire the information indicating the position of the vehicle body 250 at a predetermined cycle (every predetermined cycle). The transport information acquisition unit 102 acquires the information indicating the position of the vehicle body 250 from, for example, another control device that controls the transport device 12 or a higher-level controller.

[0094] The door opening control unit 104 controls the door opening / closing robot 14 so that the tool 70 opens the door 260 in an area upstream of the rotation axis Ax1 on the conveying line Lc. Hereinafter, the control of the door opening / closing robot 14 to open the closed door 260 is referred to as "door opening control." When the tool 70 opens the door 260 in an area upstream of the rotation axis Ax1, the tool 70 (or the rotation axis Ax4) is located in an area upstream of the rotation axis Ax1 at the time when the tool 70 first holds the door 260 in the opening operation of the door 260.

[0095] The door opening control unit 104 may control the door opening robot 14 so that the position of the tool 70 (or the rotation axis Ax4) is maintained in an area upstream of the rotation axis Ax1 during the period in which the door opening control is being performed. The door opening control unit 104 may also perform the door opening control at a stage before the end of the door 260, which is the work target and located most downstream on the conveyance line Lc, reaches the rotation axis Ax1. The door opening control unit 104 performs the door opening control, for example, so that the door 260 is opened to a position that substantially coincides with the maximum openable position.

[0096] The door following control unit 106 controls the door opening / closing robot 14 so as to maintain the door 260 in an open state while the vehicle body 250 is being transported along the transport line Lc. Hereinafter, the control by the door opening / closing robot 14 to maintain the door 260 in an open state will be referred to as "door following control." The door following control unit 106 executes the door following control after the above-described door opening control is executed. For example, the door following control unit 106 executes the door following control from the point in time when the door 260 is opened to a position that substantially coincides with the maximum openable position during the door opening control. The door following control unit 106 may continue the door following control from the point in time when the door 260 is located upstream of the rotation axis Ax1 to the point in time when the door 260 is located downstream of the rotation axis Ax1.

[0097] The door closing control unit 108 controls the door opening / closing robot 14 so that the tool 70 closes the door 260 in a region downstream of the rotation axis Ax1 on the transfer line Lc. Hereinafter, the control by the door opening / closing robot 14 to close the open door 260 is referred to as "door closing control." When the tool 70 closes the door 260 in a region downstream of the rotation axis Ax1, the tool 70 (or the rotation axis Ax4) is located in a region downstream of the rotation axis Ax1 at the start of the operation to close the door 260.

[0098] The door closing control unit 108 may control the door opening / closing robot 14 so that the position of the tool 70 (or the rotation axis Ax4) is maintained in an area downstream of the rotation axis Ax1 during the period in which the door closing control is being executed. The door closing control unit 108 executes the door closing control after the door following control is executed. The door closing control unit 108 may execute the door closing control when the most upstream end of the door 260, which has been opened by the door following control, reaches a predetermined set position on the conveying line Lc after passing the rotation axis Ax1. The door following control may be terminated by the start of execution of the door closing control. In a state in which the door 260 is closed, the door 260 is maintained in a predetermined position on the vehicle body 250 even if the tool 70 of the door opening / closing robot 14 does not hold the door 260.

[0099] Here, a series of controls including the door opening control, door following control, and door closing control is referred to as "opening / closing control." The control device 16 may store teaching information, and the control device 16 may execute the above-mentioned opening / closing control so as to operate the door opening / closing robot 14 in accordance with the stored teaching information. The teaching information is created by an operator such as a worker during a teaching stage in which the operation of the door opening / closing robot 14 is taught, and includes a program that defines the movement path of each arm.

[0100] The control device 16 executes opening / closing control for at least one of a front door and a rear door attached to the vehicle body 250. The front door is the door located at the front of a pair of doors 260 located on one side of the vehicle body 250, and the rear door is the door located behind the front door. The control device 16 may execute opening / closing control for the front door and may execute opening / closing control for the rear door.

[0101] As shown in Fig. 10, the control device 16 includes a circuit 120. The circuit 120 includes at least one processor 122, a memory 124, a storage 126, an input / output port 128, and a driver 129. The storage 126 is a computer-readable non-volatile storage medium (e.g., a flash memory). The storage 126 stores programs and data for causing the control device 16 to control the door opening / closing robot 14. The memory 124 temporarily stores programs loaded from the storage 126, calculation results by the processor 122, and the like.

[0102] The processor 122 executes the above programs in cooperation with the memory 124 to configure the above-mentioned functional modules. The driver 129 outputs drive power to the motors M1 to M5 of the door opening / closing robot 14 in response to commands from the processor 122. The input / output port 128 inputs and outputs electrical signals to and from various devices (e.g., various sensors) included in the door opening / closing robot 14 in response to commands from the processor 122. The control device 16 is not necessarily limited to one that configures each function using a program. For example, at least some of the functions of the control device 16 may be configured using a dedicated logic circuit or an ASIC (Application Specific Integrated Circuit) that integrates such logic circuits.

[0103] Next, a series of processes executed by the control device 16 will be described as an example of a control method for the door opening / closing robot 14. Fig. 11 is a flowchart showing a series of processes executed by the control device 16 in the opening / closing control of one door 260. The following describes an example in which opening / closing control is executed for the door 260 located at the front of the vehicle body 250. In an initial state, each arm of the door opening / closing robot 14 is disposed at a predetermined standby position, and the tool 70 is positioned at a predetermined height on the fourth arm 60.

[0104] The control device 16 first executes step S01. In step S01, the control device 16 waits until the vehicle body 250 to be worked on reaches a predetermined set position on the transfer line Lc. The control device 16 may determine whether the vehicle body 250 has reached the predetermined set position based on information indicating the position of the vehicle body 250 periodically obtained by the transfer information acquisition unit 102. The predetermined set position is set to a position upstream of the base 20 on the transfer line Lc. The set position is set in advance by an operator such as a worker as a position at which opening of the door 260 is to begin.

[0105] Next, the control device 16 executes step S02. In step S02, for example, the door opening control unit 104 of the control device 16 controls the door opening robot 14 to execute door opening control. The door opening control is executed, for example, as follows. First, as shown in FIG. 12(a), the door opening control unit 104 controls the door opening robot 14 so that each arm is positioned from a standby position in the initial state to a preparation position for door opening control.

[0106] In the standby position for door opening control, the first arm 30, the second arm 40, and the third arm 50 may be positioned so that they face upstream on the conveyor line Lc. Hereinafter, the state in which the first arm 30, the second arm 40, and the third arm 50 face upstream on the conveyor line Lc is defined as "State A." When the arm faces upstream on the conveyor line Lc, it means that the component of the conveyor line Lc that is the direction (orientation) from the base end of the arm toward the tip end faces upstream. Therefore, even if the arm is tilted with respect to the conveyor line Lc when viewed from above, the arm faces upstream as long as the component of the conveyor line Lc faces upstream. When the arm faces downstream on the conveyor line Lc, it means that the component of the conveyor line Lc that is the direction (orientation) from the base end of the arm toward the tip end faces downstream.

[0107] In conjunction with placing each arm at the preparation position, the door opening control unit 104 causes the fourth arm 60, which is provided with the lifting device 97, to raise the tool 70 to a height position at which the holding portion 74 of the tool 70 can pass through the window frame 262 of the door 260. Then, as shown in FIG. 12(b), the control device 16 controls the door opening / closing robot 14 to rotate the first arm 30 upstream from the preparation position and bring the second arm 40 and the third arm 50 closer to the vehicle body 250, thereby placing the holding portion 74 of the tool 70 inside the vehicle body 250.

[0108] After the holding portion 74 enters the interior of the vehicle body 250, the door opening control unit 104 lowers the tool 70 using the fourth arm 60 provided with the lifting device 97, and changes the position of the tool 70 using the door opening / closing robot 14 so that the holding portion 74 comes into (holds) contact with the door 260. When the holding portion 74 of the tool 70 first comes into contact with the door 260, the contact point (holding point) is located upstream of the rotation axis Ax1. When the holding portion 74 of the tool 70 passes through the window frame 262 and brings the holding portion 74 into contact with the closed door 260, at least a part of the third arm 50 (for example, a part of the connecting portion CS) may be disposed and operate below the vehicle body 250.

[0109] After the tool 70 holds the door 260, the door opening control unit 104 controls the door opening / closing robot 14 so that the tool 70 pulls and opens the door 260, as shown in FIG. 13(a). The door opening control unit 104 may control the door opening / closing robot 14 so that the door 260 is opened to a position that substantially coincides with the maximum position at which the door 260 can be opened. Hereinafter, the position of the door 260 opened in the door opening control is referred to as the "open position." The door opening control unit 104 may control the door opening / closing robot 14 so that the first arm 30 rotates downstream about the rotation axis Ax1 when moving the door 260 to the open position.

[0110] After moving the door 260 to the open position, the door opening control unit 104 may control the door opening / closing robot 14 so that the first arm 30 faces downstream. A state in which the first arm 30 faces downstream on the transfer line Lc and the second arm 40 and the third arm 50 face upstream on the transfer line Lc is defined as "State B." After transitioning to State A, the first arm 30 rotates around the rotation axis Ax1 so that it faces downstream, thereby transitioning the operating state of the multiple arms from State A to State B. The door opening control unit 104 may control the door opening / closing robot 14 so that it transitions from State A to State B during execution of door opening control.

[0111] The door opening control ends when the door 260 moves to the open position. When the door opening control ends, the operating state of the multiple arms may be state B. Unlike the above example, the door opening control unit 104 may control the door opening / closing robot 14 so that the state is maintained in state A during the execution of the door opening control. After transitioning to state A, the door opening control unit 104 may control the door opening / closing robot 14 so that the door 260 moves to the open position before transitioning to state B. When the door opening control ends, the operating state of the multiple arms may be state A.

[0112] As described above, in the door opening control, the control device 16 may control the door opening / closing robot 14 so that at least a portion of the third arm 50 is positioned under the vehicle body 250 when the tool 70 holds the door 260 in the closed state. In the door opening control, the control device 16 may control the door opening / closing robot 14 so that at least a portion of the second arm 40 and at least a portion of the third arm 50 are positioned under the vehicle body 250 when the tool 70 holds the door 260 in the closed state.

[0113] After executing step S02, the control device 16 executes step S03. In step S03, for example, the door following control unit 106 of the control device 16 controls the door opening / closing robot 14 to execute door following control. The door following control is executed, for example, as follows. From the state where the door opening control has ended, the door following control unit 106 controls the door opening / closing robot 14 to rotate the first arm 30 downstream about the rotation axis Ax1 while following the movement of the vehicle body 250, so as to maintain the door 260 in an open state, as shown in FIG. 13(b) and FIG. 14(a).

[0114] The door following control unit 106 may control the door opening / closing robot 14 to rotate the first arm 30 about the rotation axis Ax1 from the rotation start position at the end of the door opening control to a predetermined set position and stop it, while maintaining the door 260 in an open state. The door following control unit 106 may control the door opening / closing robot 14, in the previous stage of the door following control, to rotate the first arm 30 about the rotation axis Ax1 from the rotation start position to the set position and stop it.

[0115] The door following control unit 106 may control the door opening / closing robot 14 so that the amount of change in the rotation angle of the first arm 30 per unit time is constant (substantially constant) when rotating the first arm 30 from the rotation start position to the set position. When the door opening control ends in state A, the operating states of the multiple arms may transition from state A to state B while the first arm 30 is rotating to the set position.

[0116] 14(a) shows a state in which the first arm 30 is stopped at the set position. The set position at which the first arm 30 is stopped is set so that the tip 34 of the first arm 30 does not come into contact with the booth side wall 204 when the first arm 30 is stopped. The set position may be set so that, when the first arm 30 is stopped, at least a portion of the tip 34 of the first arm 30 overlaps with the base 20 when the base 20 is viewed from the direction along the transfer line Lc (the X-axis direction). In this case, when the first arm 30 is stopped at the set position, at least a portion of the base end 32 is located at the same position as at least a portion of the base 20 in the Y-axis direction.

[0117] The door tracking control unit 106 may control the door opening / closing robot 14 so that the first arm 30 stops at the set position while the multiple arms are maintained in state B. The door tracking control unit 106 may control the door opening / closing robot 14 so that the first arm 30 stops at the set position before the leading edge of the door 260 held by the tool 70 reaches the base 20 in the X-axis direction along the transfer line Lc. In this case, the first arm 30 stops at the set position when the leading edge of the door 260 held by the tool 70 is located upstream of the base 20 on the transfer line Lc.

[0118] After transitioning to state B, the door following control unit 106 may control the door opening / closing robot 14 so that the angle θ1 of the second arm 40 relative to the first arm 30 is maintained at less than 90° while the first arm 30 is being rotated to the set position. The angle θ1 is the angle of the imaginary line segment connecting the rotation axis Ax2 and the rotation axis Ax3 when viewed from the top-bottom direction, with the imaginary line segment connecting the rotation axis Ax1 and the rotation axis Ax2 set at 0° (reference angle) and one direction of rotation around the rotation axis Ax2 (clockwise in FIG. 13(b)) being positive.

[0119] 14(b) and 15(a), the door following control unit 106 controls the door opening / closing robot 14 to rotate the second arm 40 downstream about the rotation axis Ax2, while following the movement of the vehicle body 250, so that the door 260 is maintained in an open state. In the door following control, the door following control unit 106 may control the door opening / closing robot 14 so that the first arm 30 remains at the set position after stopping the first arm 30 at the set position.

[0120] 14(b), as the second arm 40 rotates around the rotation axis Ax2, the third arm 50 transitions to a state in which it faces downstream while facing upstream. The state in which the first arm 30 and the second arm 40 face downstream on the transfer line Lc and the third arm 50 faces upstream on the transfer line Lc is defined as "State C." After stopping the first arm 30 at the set position, the door following control unit 106 may control the door opening / closing robot 14 so that the operating states of the multiple arms transition from State B to State C.

[0121] After transitioning to state C, the door following control unit 106 may control the door opening / closing robot 14 so that the leading edge of the door 260 held by the tool 70 passes through the base 20. In this case, state C is maintained from the time when the leading edge of the door 260 reaches one end located upstream of the base 20 in the direction along the conveying line Lc until the time when the leading edge of the door 260 reaches the other end located downstream of the base 20.

[0122] After transitioning to state C, the door following control unit 106 may control the door opening / closing robot 14 so that the angle θ2 of the third arm 50 relative to the second arm 40 is maintained smaller than 90° while the tip of the door 260 held by the tool 70 passes the base 20. The angle θ2 is the angle of the imaginary line segment connecting the rotation axis Ax3 and the rotation axis Ax4 when viewed from the top-bottom direction, with the imaginary line segment connecting the rotation axis Ax2 and the rotation axis Ax3 set to 0° (reference angle) and one direction of rotation around the rotation axis Ax3 (clockwise in FIG. 14(b)) set to positive.

[0123] 15(a) shows a state in which, after transition to state C, the second arm 40 is rotated about the rotation axis Ax2 to a position where the tip 44 of the second arm 40 overlaps with the base 20 in the Y-axis direction. After transition to state C, the door following control unit 106 may control the door opening / closing robot 14 to rotate the second arm 40 until the imaginary line segment connecting the rotation axis Ax1, the rotation axis Ax2, and the rotation axis Ax3 becomes nearly straight.

[0124] After the second arm 40 has rotated until the virtual line segment becomes nearly straight, as shown in Fig. 15(b), the door following control unit 106 may control the door opening / closing robot 14 to rotate the third arm 50 downstream about the rotation axis Ax3 while following the movement of the vehicle body 250 and maintaining the door 260 in an open state. While the third arm 50 is being rotated downstream, the door following control unit 106 may control the door opening / closing robot 14 so that the first arm 30 remains at the set position and the rotation angle of the second arm 40 changes.

[0125] As the third arm 50 rotates around the rotation axis Ax3, the first arm 30 and the second arm 40 transition to a state in which they face downstream, and the third arm 50 transitions to a state in which they face downstream. The state in which the first arm 30, the second arm 40, and the third arm 50 face downstream on the conveying line Lc is defined as "state D." The door following control unit 106 may control the door opening / closing robot 14 to transition from state C to state D while the door following control is being executed.

[0126] The door following control unit 106 may control the door opening / closing robot 14 so that the door 260 is maintained in an open state until a predetermined tracking end position downstream of the base 20 on the conveying line Lc is reached. After transitioning to state D, the door following control unit 106 may control the door opening / closing robot 14 so that the door following control is terminated without the operation states of the multiple arms transitioning to other states. The door following control unit 106 may control the door opening / closing robot 14 so that the operation states transition from state B to state C and from state C to state D while the door following control is being performed. After transitioning to state D, the door following control unit 106 may control the door opening / closing robot 14 so that the angle θ2 of the third arm 50 with respect to the second arm 40 is maintained smaller than 180° while the door following control is being performed.

[0127] During the door following control, the door following control unit 106 may control the door opening / closing robot 14 so that the location where the tool 70 holds the door 260 (hereinafter referred to as the "holding location hp") moves on a holding line Lh that is parallel to the conveying line Lc. The holding location hp is, for example, the location where the holding portion 74 of the tool 70 contacts the inner surface 264 of the door 260 when viewed from the top and bottom. As shown in FIGS. 13(a) to 15(b), the door following control unit 106 may control the door opening / closing robot 14 so that the movement trajectory of the holding location hp during the door following control is substantially parallel to the conveying line Lc.

[0128] In one example, during door following control, the door following control unit 106 controls the door opening / closing robot 14 so that the holding point hp where the tool 70 holds the door 260 moves along the holding line Lh while maintaining the position and posture of the tool 70 (or the fourth arm 60) relative to the open door 260. During door following control, the door following control unit 106 may control the door opening / closing robot 14 so that the imaginary line connecting the point where the tool 70 contacts the door 260 (holding point hp) and the rotation axis Ax4 maintains a predetermined angle with respect to the door 260 when viewed from the top and bottom direction.

[0129] After executing step S03, the control device 16 executes step S04. In step S04, for example, the door closing control unit 108 of the control device 16 controls the door opening / closing robot 14 to execute door closing control. The door closing control is executed, for example, as follows. For example, the door closing control unit 108 controls the door opening / closing robot 14 so that the tool 70 pulls the door 260 to bring the door 260 closer to the vehicle body 250, while maintaining a state in which the tool 70 holds the door 260 (for example, a state in which the door 260 is attracted by magnetic force), as shown in FIG. 16(a). At the time of starting the operation to close the door 260, the location where the holding portion 74 of the tool 70 is in contact with the door 260 (holding location) is located downstream of the rotation axis Ax1.

[0130] The door closing control unit 108 may cause the door opening / closing robot 14 to move the door 260 from the open position to the closed position while rotating the third arm 50 about the rotation axis Ax3 toward the upstream side from the point at which the door following control ended. After the door 260 is closed, the door closing control unit 108 causes the fourth arm 60, to which the lifting device 97 is attached, to raise the tool 70 to a height position at which the holding portion 74 of the tool 70 can pass through the window frame 262 of the door 260. Then, the door closing control unit 108 controls the door opening / closing robot 14 so that the second arm 40 and the third arm 50 move away from the vehicle body 250 and the holding portion 74 of the tool 70 passes through the window frame 262. As a result, the holding portion 74 of the tool 70 is moved outside the vehicle body 250. When the holding portion 74 is moved outside the vehicle body 250, the door closing control ends.

[0131] After the door closing control is completed, the control device 16 may control each arm to be placed in the standby position before execution of step S02, as shown in Fig. 16(b). While the control device 16 is moving each arm to the standby position, the control device 16 may use the fourth arm 60 provided with the lifting device 97 to lower the tool 70 to a height position where the holding portion 74 cannot pass through the window frame 262. This completes the series of controls involved in the opening / closing control for one door 260.

[0132] The second arm 40 may operate at a position (low height range) lower than the lower end of the door 260 of the vehicle body 250 being transported along the transport line Lc during the period when the door opening control, door following control, and door closing control are performed. The second arm 40 and the third arm 50 may operate at a position (low height range) lower than the lower end of the door 260 of the vehicle body 250 being transported along the transport line Lc during the period when the door opening control, door following control, and door closing control are performed.

[0133] The control device 16 may control the door opening / closing robot 14 so that the angle θ2 of the third arm 50 relative to the second arm 40 is maintained at less than 180° during the period when the door opening control, door following control, and door closing control are performed.

[0134] FIG. 17 shows a schematic diagram of the transition of operational states of multiple arms during opening and closing control, including door opening control, door following control, and door closing control. Seven operational states are shown for multiple arms in FIG. 17, with the states transitioning from top to bottom on the page of FIG. 17. The workpiece W (car body 250) is transported from left to right on the page of FIG. 17. "x0" represents the position of the rear end of the car body 250 in the X-axis direction along the transport line Lc when opening and closing control is initiated. "x1" and "y1" represent the installation position of the base 20 (position of the rotation axis Ax1). "x1" represents the position in the X-axis direction along the transport line Lc, and "y1" represents the position in the Y-axis direction perpendicular to the transport line Lc.

[0135] As shown in the enlarged view of Figure 17, the line extending from rotation axis Ax1 located at x1, y1 to the next point (rotation axis Ax2) represents first arm 30, and the line extending from rotation axis Ax2 to the next point (rotation axis Ax3) represents second arm 40. The line extending from rotation axis Ax3 to the next point (rotation axis Ax4) represents third arm 50, and the line extending from rotation axis Ax4 to the next point represents tool 70. Fourth arm 60 is formed to extend in the vertical direction, so it is omitted from Figure 17.

[0136] 17, the control device 16 starts door opening control after transitioning to State A in which the first arm 30, the second arm 40, and the third arm 50 face upstream on the conveyor line Lc. After transitioning to State A, the control device 16 controls the door opening / closing robot 14 so that the first arm 30 rotates to a state in which it faces downstream before the other arms. As a result, during execution of the door opening control or the door following control, a transition occurs from State A to State B in which the first arm 30 faces downstream on the conveyor line Lc, and the second arm 40 and the third arm 50 face upstream on the conveyor line Lc.

[0137] After transitioning to state B, the control device 16 controls the door opening / closing robot 14 so that the second arm 40 rotates until it faces downstream before the third arm 50. As a result, during execution of the door following control, the state transitions from state B to state C in which the first arm 30 and the second arm 40 face downstream on the conveyor line Lc and the third arm 50 faces upstream on the conveyor line Lc. After transitioning to state C, the control device 16 controls the door opening / closing robot 14 so that it rotates until it finally faces downstream. As a result, during execution of the door following control, the state transitions from state C to state D.

[0138] After transitioning to state D, the control device 16 ends the door following control without transitioning the operation states of the multiple arms to other states, and executes door closing control. For convenience of explanation, the above operation shown in Fig. 17 is referred to as "operation pattern 1." In operation pattern 1, the control device 16 controls the door opening / closing robot 14 to transition to state A, state B, state C, and state D in that order during the period in which the door opening control and door following control are executed.

[0139] The control device 16 may execute opening and closing control by an operation different from operation pattern 1. FIG. 18 schematically shows the transition of the operation states of the multiple arms in "operation pattern 2" different from operation pattern 1. In FIG. 18, seven operation states are shown for the multiple arms, similar to FIG. 17. The way of expressing the state transitions in FIG. 18 is the same as that in FIG. 17.

[0140] In operation pattern 2, similar to operation pattern 1, a transition from state A to state B occurs during execution of door opening control or door following control. After transition to state B, the control device 16 controls the door opening / closing robot 14 so that the third arm 50 rotates until it faces downstream ahead of the second arm 40. As a result, during execution of door following control, a transition occurs from state B to a state in which the first arm 30 and the third arm 50 face downstream on the conveyor line Lc, and the second arm 40 faces upstream on the conveyor line Lc. The state in which the first arm 30 and the third arm 50 face downstream on the conveyor line Lc, and the second arm 40 faces upstream on the conveyor line Lc is defined as "state E."

[0141] After transitioning to State E, the control device 16 controls the door opening / closing robot 14 so that it finally rotates until the second arm 40 faces downstream. As a result, during execution of the door following control, the robot transitions from State E to State D. In operation pattern 2, the control device 16 controls the door opening / closing robot 14 so that it transitions sequentially through State A, State B, State E, and State D during the period during which the door opening control and door following control are executed.

[0142] FIG. 19 schematically shows the transition of the motion states of the multiple arms in "motion pattern 3," which is different from motion pattern 1 and motion pattern 2. FIG. 19 shows nine motion states for the multiple arms. The way in which the state transitions are expressed in FIG. 19 is the same as that in FIG. 17.

[0143] After transitioning to State A, the control device 16 controls the door opening / closing robot 14 so that the second arm 40 rotates to a state where it faces downstream before the other arms. As a result, during execution of the door opening control or the door following control, the robot transitions from State A to a state where the second arm 40 faces downstream on the transfer line Lc, and the first arm 30 and the third arm 50 face upstream on the transfer line Lc. The state where the second arm 40 faces downstream on the transfer line Lc, and the first arm 30 and the third arm 50 face upstream on the transfer line Lc is defined as "State F."

[0144] After transitioning to State F, the control device 16 controls the door opening / closing robot 14 to rotate until the third arm 50 faces downstream ahead of the first arm 30. As a result, during execution of the door tracking control, the state transitions from State F to a state in which the second arm 40 and the third arm 50 face downstream on the transfer line Lc, and the first arm 30 faces upstream on the transfer line Lc. The state in which the second arm 40 and the third arm 50 face downstream on the transfer line Lc, and the first arm 30 faces upstream on the transfer line Lc is defined as "State G."

[0145] After transitioning to state G, the control device 16 controls the door opening / closing robot 14 so that the first arm 30 rotates until it finally faces downstream. As a result, a transition from state G to state D occurs during execution of the door following control. In operation pattern 3, the control device 16 controls the door opening / closing robot 14 so that it transitions sequentially through states A, F, G, and D during the period in which the door opening control and the door following control are executed. Each of operation patterns 1 to 3 is an example of the operation of multiple arms, and the control device 16 may control the door opening / closing robot 14 to operate in an operation pattern different from operation patterns 1 to 3.

[0146] As shown in Fig. 20, the painting system 1 may include two door opening / closing robots 14 lined up along the transfer line Lc. The two door opening / closing robots 14 are arranged between the transfer line Lc and the booth side wall 204. Hereinafter, one of the two door opening / closing robots 14 will be referred to as "door opening / closing robot 14A," and the door opening / closing robot 14 arranged downstream of the door opening / closing robot 14A will be referred to as "door opening / closing robot 14B."

[0147] The control device 16 controls the door opening / closing robot 14A and the door opening / closing robot 14B (second door opening / closing robot). The control device 16 may have a controller (computer device) that controls the door opening / closing robot 14A and a controller (computer device) that controls the door opening / closing robot 14B. These two controllers may be communicably connected to each other. Each controller may have the circuit 120 shown in FIG. 10. The control device 16 may be a control system made up of multiple controllers.

[0148] The control device 16 causes the door opening / closing robot 14A to execute an opening / closing control (first control) in which door opening control, door following control, and door closing control are sequentially performed on one door 260. The control device 16 causes the door opening / closing robot 14B to execute an opening / closing control (second control) in which door opening control, door following control, and door closing control are sequentially performed on the door 260 after it has been opened and closed by the door opening / closing robot 14A. The robot device 18 may include the door opening / closing robots 14A and 14B and the control device 16.

[0149] Here, the door 260 located forward on one side of the vehicle body 250 is referred to as the "front door 260a," and the door 260 attached to the vehicle body 250 behind the front door 260a is referred to as the "rear door 260b." The control device 16 may use the door opening / closing robot 14A to sequentially execute opening / closing control for the front door 260a and the rear door 260b. The control device 16 may use the door opening / closing robot 14B to sequentially execute opening / closing control for the front door 260a and the rear door 260b.

[0150] 21 is a flowchart showing a series of processes performed by the control device 16 when two door opening / closing robots 14 perform opening / closing control on the front door 260a and the rear door 260b, respectively. In this series of processes, the control device 16 executes step S11 in a state where the front door 260a of the vehicle body 250 to be worked on is located upstream of the base 20 on the transfer line Lc. In step S11, for example, the control device 16 waits until the vehicle body 250 to be worked on reaches a predetermined first set position on the transfer line Lc, similar to step S01 described above.

[0151] Next, the control device 16 executes step S12. In step S12, for example, the control device 16 causes the door opening / closing robot 14A to execute opening / closing control (first control) on the front door 260a (door). The control device 16 may execute opening / closing control on the front door 260a in the same manner as in steps S02 to S04 described above. After the operation states of the multiple arms transition to state A, the control device 16 may start door opening control on the front door 260a and control the door opening / closing robot 14 to transition sequentially to state A, state B, and state C. After transition to state C, the control device 16 may control the door opening / closing robot 14 to end the door tracking control on the front door 260a without transitioning to another state. FIG. 20 illustrates an example in which the door opening / closing robot 14B is on standby and the door opening / closing robot 14A is in the middle of executing opening / closing control on the front door 260a.

[0152] Next, the control device 16 executes step S13. In step S13, for example, the control device 16 waits until the vehicle body 250 to be worked on reaches a predetermined second set position on the transfer line Lc. The second set position is set to a position downstream of the first set position used in step S11.

[0153] Next, the control device 16 executes step S14. In step S14, for example, the control device 16 executes opening / closing control (second control) on the front door 260a by using the door opening / closing robot 14B. The control device 16 may execute opening / closing control on the front door 260a in the same manner as in steps S02 to S04 described above. As in step S12, after transitioning to state A, the control device 16 may start door opening control on the front door 260a, transition to state A, state B, and state C in order, and then terminate the door following control on the front door 260a without transitioning to another state.

[0154] The control device 16 executes step S15 during a period overlapping with at least a part of the execution period of step S14 (second control). In step S15, for example, the control device 16 executes opening / closing control (third control) on the rear door 260b (second door) by using the door opening / closing robot 14A. The control device 16 may execute the opening / closing control on the rear door 260b in the same manner as in steps S02 to S04 described above. Unlike step S12, the control device 16 may start the door opening control after transitioning to state B, transition to state B, state C, and state D in that order, and then terminate the door following control after transitioning to state D.

[0155] 22 illustrates an example of the state in which the door opening / closing robot 14A is executing opening / closing control on the rear door 260b and the door opening / closing robot 14B is executing opening / closing control on the front door 260a. As shown in FIG. 22, during at least a portion of the execution period of step S15 (third control), the second arm 40 and the third arm 50 of the door opening / closing robot 14A that is opening the rear door 260b may operate below the front door 260a that has been opened by the door opening / closing robot 14B. During this portion of the period, the second arm 40 and the third arm 50 of the door opening / closing robot 14A may operate with at least a portion of the second arm 40 and the third arm 50 positioned vertically below the front door 260a. During at least a portion of the execution period of step S15, at least a portion of the front door 260a may overlap at least a portion of the second arm 40 and the third arm 50 of the door opening / closing robot 14A when viewed from the top-bottom direction.

[0156] Next, the control device 16 executes step S16. In step S16, for example, the control device 16 waits until the vehicle body 250 to be worked on reaches a predetermined third set position on the transfer line Lc. The third set position is set to a position downstream of the second set position used in step S13.

[0157] Next, the control device 16 executes step S17. In step S17, for example, the control device 16 executes opening / closing control (fourth control) on the rear door 260b (second door) by the door opening / closing robot 14B. The control device 16 may execute the opening / closing control on the rear door 260b in the same manner as in steps S02 to S04 described above. Unlike step S14, the control device 16 may start the door opening control after transitioning to state B, transition to state B, state C, and state D in order, and then terminate the door following control without transitioning to another state. FIG. 23 illustrates an example in which the door opening / closing robot 14A is on standby and the door opening / closing robot 14B is in the middle of executing the opening / closing control on the rear door 260b.

[0158] The series of processes shown in each of Figures 11 and 21 are examples and can be modified as appropriate. In the series of processes described above, the control device 16 may execute one step and the next step in parallel, or may execute the steps in an order different from that of the above-described example. The control device 16 may omit any step, or may execute a process in any step different from that of the above-described example. In any step of the series of processes shown in Figure 21, the control device 16 may control the door opening / closing robot 14 so that each arm operates according to operation pattern 1, operation pattern 2, operation pattern 3, part of operation pattern 2, or part of operation pattern 3.

[0159] The coating system 1 may include three or more door opening / closing robots 14 arranged between the transport device 12 and one of the pair of booth side walls 204. The coating system 1 may further include one or more door opening / closing robots 14 arranged between the transport device 12 and the other of the pair of booth side walls 204. The number of the one or more door opening / closing robots 14 arranged between the transport device 12 and one booth side wall 204 may be the same as the number of the one or more door opening / closing robots 14 arranged between the transport device 12 and the other booth side wall 204.

[0160] The example of the door opening / closing robot 14 described above includes a base 20, first arms 30 and 30B, second arms 40, 40A and 40B, third arms 50, 50A and 50B, and a fourth arm 60. The base 20 is provided at a position different from the conveyor line Lc along which the vehicle body 250 to be worked on is conveyed. The first arms 30 and 30B are attached to the base 20 so as to rotate about a rotation axis Ax1 along the vertical direction, and extend in a direction away from the rotation axis Ax1. The second arms 40, 40A and 40B are attached to the first arms 30 and 30B so as to rotate about a rotation axis Ax2 parallel to the rotation axis Ax1, and extend in a direction away from the rotation axis Ax2. The third arms 50, 50A, 50B are attached to the second arms 40, 40A, 40B so as to rotate around a rotation axis Ax3 parallel to the rotation axis Ax1, and extend in a direction away from the rotation axis Ax3. The fourth arm 60 is attached to the third arms 50, 50A, 50B so as to extend in the vertical direction at the tip ends 54, 54A, 54B of the third arms 50, 50A, 50B, and moves a tool 70 capable of holding a door 260 attached to the vehicle body 250 in the vertical direction. In the vertical direction, at least a portion of coupling portions CS, CSA, CSB including the tip ends 44, 44A, 44B of the second arms 40, 40A, 40B and the base ends 52, 52A, 52B of the third arms 50, 50A, 50B, and at least a portion of the base 20 are positioned at the same height.

[0161] The door opening / closing robot 14 has three arms that rotate around rotation axes along the vertical direction. Therefore, even if the base 20 of the door opening / closing robot 14 is attached in a predetermined position, it can follow the vehicle body 250 being transported and maintain the door 260 in an open state over a wide range. Furthermore, even if three arms are provided, at least a portion of the connecting parts CS, CSA, and CSB are positioned at the same height as at least a portion of the base 20, thereby reducing the vertical size of the door opening / closing robot 14 and preventing interference with other components. This allows the base 20 to be installed close to the transport line Lc along which the vehicle body 250 is transported. Therefore, the door opening / closing robot 14 is useful for saving space in the painting area.

[0162] The second arms 40, 40A, 40B and the third arms 50, 50A, 50B may be provided to operate below the door 260 held by the tool 70. In this case, even when the second arms 40, 40A, 40B and the third arms 50, 50A, 50B are operated, interference with the workpiece W can be avoided, and the base 20 can be positioned close to the transfer line Lc. This is therefore useful for saving space in the area where the workpiece W is painted.

[0163] In the vertical direction, the uppermost positions of the portions of the second arms 40, 40A, 40B other than the distal ends 44, 44A, 44B and the portions of the third arms 50, 50A, 50B other than the proximal ends 52, 52A, 52B may be lower than the uppermost positions of the connectors CS, CSA, CSB. In this case, the connectors CS, CSA, CSB are the highest in the second arms 40, 40A, 40B and the third arms 50, 50A, 50B. However, as described above, the height positions of the connectors CS, CSA, CSB are within the height range of the base 20. This allows for a wider operating area for other components (e.g., a painting robot) above the second arms 40, 40A, 40B and the third arms 50, 50A, 50B. This is useful for avoiding interference between other components and the door opening / closing robot 14.

[0164] In the vertical direction, the connection points between the first arms 30, 30B and the second arms 40, 40A, 40B may be located at the same height as at least a portion of the coupling portions CS, CSA, CSB. In this case, the vertical size of the portion including the first arms 30, 30B, the second arms 40, 40A, 40B, and the third arms 50, 50A, 50B is reduced. This is therefore useful for miniaturizing the door opening / closing robot 14.

[0165] The example of the door opening / closing robot 14 described above includes a base 20 provided at a position different from the conveying line Lc along which the vehicle body 250 to be worked on is conveyed, first arms 30, 30B attached to the base 20 so as to rotate about a rotation axis Ax1 along the vertical direction and extending in a direction away from the rotation axis Ax1, and second arms 40, 40A, 40B attached to the first arms 30, 30B so as to rotate about a rotation axis Ax2 parallel to the rotation axis Ax1 and extending in a direction away from the rotation axis Ax2. The door 260 includes a third arm 50, 50A, 50B attached to the second arm 40, 40A, 40B so as to rotate about a rotation axis Ax3 parallel to the rotation axis Ax1 and extending in a direction away from the rotation axis Ax3, and a fourth arm 60 attached to the third arm 50, 50A, 50B so as to extend in the vertical direction at a tip end 54, 54A, 54B of the third arm 50, 50A, 50B, the fourth arm 60 moving a tool 70 capable of holding a door 260 attached to the vehicle body 250 in the vertical direction. The fourth arm 60 holds the tool 70 so that it can be raised and lowered to pass through a window frame 262 of the door 260. In the vertical direction, a connection point between the third arm 50, 50A, 50B and the fourth arm 60 is lower than the uppermost positions of the second arm 40, 40A, 40B and the third arm 50, 50A, 50B. The second arms 40, 40A, 40B and the third arms 50, 50A, 50B are arranged to operate below the door 260 of the vehicle body 250 being transported along the transport line Lc. In the vertical direction, at least a portion of the tip ends 54, 54A, 54B of the third arms 50, 50A, 50B and at least a portion of the second arms 40, 40A, 40B are positioned at the same height.

[0166] The door opening / closing robot 14 described above has three arms that rotate around rotation axes along the vertical direction. Therefore, unlike conventional methods, the door opening / closing robot 14 itself (the entire robot) does not need to be moved in the X-axis direction by a device for transporting the door opening / closing robot 14. The door opening / closing robot 14 can follow the vehicle body 250 being transported and maintain the door 260 in an open state over a wide range. Because the connection point between the third arm and the fourth arm is lower than the uppermost position of the second arm and the third arm, the vertical size of the door opening / closing robot 14 is reduced even if the lifting range of the tool 70 by the fourth arm is extended. Furthermore, because the vertical size is reduced in this manner, the second arm and the third arm can operate below the door 260. Since at least a portion of the tip of the third arm and at least a portion of the second arm are positioned at the same height in the vertical direction, the vertical size of the door opening / closing robot 14 is reduced. This avoids interference with other components, and the door opening / closing robot 14 can be positioned close to the transport line Lc along which the vehicle body 250 is transported. Therefore, the door opening and closing robot 14 is useful for saving space in the painting area.

[0167] The second arms 40, 40A, 40B and the third arms 50, 50A, 50B may be arranged to operate below the vehicle body 250 being transported along the transport line Lc. In this case, even if the door opening / closing robot 14 is brought closer to the transport line Lc, interference with the workpiece W can be avoided. Furthermore, by arranging the second and third arms at low positions, the range of interference with the painting robot while the door is open is reduced. This is therefore even more useful for saving space in the painting area.

[0168] The second arm 40 may be attached below the tip 34 of the first arm 30. The third arm 50 may be attached above the tip 44 of the second arm 40. In this case, the vertical size of the portion including the first arm, second arm, and third arm can be reduced. This is therefore useful for miniaturizing the door opening / closing robot 14.

[0169] In the vertical direction, the tip 54 of the third arm 50 may be lower than the base end 52 of the third arm 50. In this case, the range in which the tool 70 can be raised and lowered by the fourth arm 60 is wider than when the tip 54 is positioned at the same height as the base end 52. By increasing the range in which the tool 70 can be raised and lowered, it becomes possible to work on a wider variety of vehicle bodies 250 (workpieces W) using a door opening / closing robot 14 with the same specifications. This is therefore useful for sharing the door opening / closing robot 14.

[0170] In the vertical direction, the uppermost position of the second arm 40 may be lower than the uppermost position on the underside of the portion (intermediate portion 36) of the first arm 30 between the base end portion 32 and the tip end portion 34. In this case, when the second arm 40 is bent so as to approach the first arm 30, the first arm 30 and the second arm 40 are less likely to interfere with each other. This is therefore useful for expanding the movable range of the second arm 40.

[0171] The second arm 40A may be attached below the tip 34 of the first arm 30. The third arm 50A may be attached below the tip 44A of the second arm 40A. Unlike a configuration including the second arm 40 and the third arm 50, the third arm 50A can be formed in a straight line when the tip of the third arm is lowered. This is therefore useful for simplifying the third arm.

[0172] In the vertical direction, the tip 44A of the second arm 40A may be higher than the base end 42A of the second arm 40A. In this case, the lifting range of the tool 70 by the fourth arm 60 is wider than when the tip 44A is positioned at the same height as the base end 42A. By increasing the lifting range of the tool 70, it becomes possible to work on a wider variety of vehicle bodies 250 (workpieces W) using a door opening / closing robot 14 with the same specifications. This is therefore useful for sharing the door opening / closing robot 14.

[0173] The second arm 40B may be attached above the tip 34B of the first arm 30B. The third arm 50B may be attached below the tip 44B of the second arm 40B. Unlike a configuration including the second arm 40 and the third arm 50, or the second arm 40A and the third arm 50A, the second arm 40B and the third arm 50B can be formed in a straight line when the tip of the third arm is lowered. This is therefore useful for simplifying the second arm and the third arm.

[0174] In the vertical direction, the tip 34B of the first arm 30B may be lower than the base end 32B of the first arm 30B. In this case, the lifting range of the tool 70 by the fourth arm 60 is wider than when the tip 34B is positioned at the same height as the base end 32B. By increasing the lifting range of the tool 70, it becomes possible to work on a wider variety of vehicle bodies 250 (workpieces W) using a door opening / closing robot 14 with the same specifications. This is therefore useful for sharing the door opening / closing robot 14.

[0175] The first arms 30, 30B may be attached to the base 20. In this case, the base 20 is simplified, which is useful for making the door opening and closing robot 14 smaller.

[0176] In the vertical direction, at least a portion of the second arms 40, 40A, 40B and at least a portion of the base 20 may be positioned at the same height. In this case, the size of the door opening / closing robot 14 in the vertical direction can be reduced. Therefore, this is useful for miniaturizing the door opening / closing robot 14.

[0177] In the vertical direction, the uppermost position of the base ends 32, 32B of the first arms 30, 30B may be lower than the lowermost position of the door 260 of the vehicle body 250 being transported along the transport line Lc. In this case, it is easy to avoid interference between the first arms 30, 30B and other members such as the workpiece W, and the door opening / closing robot 14 can be positioned close to the other members. This is therefore useful for preventing the painting area from becoming larger due to the operation of the door opening / closing robot 14.

[0178] In the vertical direction, the uppermost positions of the second arms 40, 40A, 40B and the third arms 50, 50A, 50B may be lower than the lowermost position of the door 260 of the vehicle body 250 being transported along the transport line Lc. In the vertical direction, the lowermost positions of the second arms 40, 40A, 40B and the third arms 50, 50A, 50B may be higher than the booth bottom wall 202 on which the transport device 12 that transports the vehicle body 250 along the transport line Lc is provided. In the vertical direction, at least a portion of the base ends 32, 32B of the first arms 30, 30B may be positioned at the same height as the lowermost position of the door 260 of the vehicle body 250 being transported along the transport line Lc. In this case, the second arms and the third arms operate in the area between the lower end of the door 260 and the booth bottom wall 202, and are therefore less likely to interfere with other components such as the workpiece W. Furthermore, by arranging the base ends 32, 32B of the first arms 30, 30B in the same height range as the lower end of the door 260, the horizontal size of the base ends 32, 32B can be reduced. This is therefore useful for preventing interference between the door opening / closing robot 14 and other components and for reducing the size of the door opening / closing robot 14.

[0179] In the vertical direction, the uppermost positions of the second arms 40, 40A, 40B and the third arms 50, 50A, 50B may be lower than the uppermost positions of the first arms 30, 30B. In this case, an area in which other members can operate is formed next to the area in which the first arms 30, 30B operate. This is therefore useful for avoiding interference with other members.

[0180] In the vertical direction, the lowest positions of the second arms 40, 40A, and 40B and the lowest positions of the third arms 50, 50A, and 50B may be approximately the same. In this case, the size of the door opening / closing robot 14 in the vertical direction is further reduced. This is therefore useful for miniaturizing the door opening / closing robot 14.

[0181] The base 20 may be installed so that the side surface (side surface 24a) that is the shortest distance from the rotation axis Ax1 faces the transfer line Lc when viewed from the top-bottom direction. In this case, the portion between the base 20 and the transfer line Lc that protrudes toward the transfer line Lc beyond the rotation axis Ax1 is small. Therefore, even if the base 20 is brought close to the transfer line Lc, interference with the workpiece W is avoided. This is therefore useful for saving space in the width direction of the painting area that is perpendicular to the transfer line Lc.

[0182] The door opening / closing robot 14 may further include a motor M1 that generates a first driving force for rotating the first arm 30 about the rotation axis Ax1, and a motor M2 that generates a second driving force for rotating the second arm 40 about the rotation axis Ax2. The motors M1 and M2 may be disposed on the first arm 30. In this case, the base 20 can be simplified compared to when the motors are disposed on the base 20, and work on the motors M1 and M2 is easier. This is therefore useful for reducing the size of the base 20 and improving maintainability.

[0183] The motor M1 may include a motor body 81a and an output shaft 81b. The motor M2 may include a motor body 82a and an output shaft 82b. The motor M1 may be attached from above with the output shaft 81b facing downward. The motor M2 may be attached from above with the output shaft 82b facing downward. In this case, the motors M1 and M2 can be easily removed. This is therefore useful for improving maintainability.

[0184] The door opening / closing robot 14 may further include a motor M3 that generates a third driving force for rotating the third arm 50 about the rotation axis Ax3. The motor M3 may be arranged in the second arm 40 so that the distance between the motor M3 and the rotation axis Ax2 is smaller than the distance between the motor M3 and the rotation axis Ax3. In this case, it is possible to avoid a reduction in the movable range of the third arm 50 due to the arrangement of the motor M3, and this is useful for reducing the moment of inertia.

[0185] The motor M3 may include a motor body 83a and an output shaft 83b. The motor M3 may be attached from above with the output shaft 83b facing downward. In this case, the motor M3 can be easily removed. This is useful for improving maintainability.

[0186] When viewed from the top-bottom direction, the side portions 43 of the second arm 40 may be formed to be recessed inward. In this case, when the third arm 50 is bent so as to approach the second arm 40, the second arm 40 and the third arm 50 are less likely to interfere with each other. This is therefore useful for expanding the movable range of the third arm 50.

[0187] The fourth arm 60 may be attached to the tip ends 54, 54A, 54B of the third arms 50, 50A, 50B so as to rotate together with the tool 70 about a rotation axis Ax4 parallel to the rotation axis Ax1. In this case, when the door 260 is opened by the tool 70, the posture of the tool 70 is adjusted by rotating the fourth arm 60 about the rotation axis Ax4. This is therefore useful for simplifying the operation of arms other than the fourth arm 60.

[0188] The door opening / closing robot 14 may further include a motor M4 that generates a fourth driving force for rotating the fourth arm 60 about the rotation axis Ax4, and a motor M5 that generates a fifth driving force for moving the tool 70 in the up-down direction. The motors M4 and M5 may be disposed on the third arm 50. In this case, the fourth arm 60 is made smaller than when at least one of the motors M4 and M5 is disposed on the fourth arm 60. This is therefore useful for reducing the operating range of the fourth arm 60. For example, when increasing the pressure inside the door opening / closing robot, it is not necessary to dispose a motor on the fourth arm 60, which eliminates the need to increase the pressure inside the fourth arm 60. This is therefore useful for simplifying the door opening / closing robot 14.

[0189] The motor M4 may include a motor body 84a and an output shaft 84b. The motor M5 may include a motor body 85a and an output shaft 85b. The motor M4 may be attached from above with the output shaft 84b facing downward. The motor M5 may be attached from above with the output shaft 85b facing downward. In this case, the motors M4 and M5 can be easily removed. This is therefore useful for improving maintainability.

[0190] The fourth arm 60 may include a fixed part 62 attached to the tip end 54, 54A, 54B of the third arm 50, 50A, 50B and rotatable about the rotation axis Ax4, and a movable part 64 attached to the fixed part 62 and movable up and down. The movable part 64 is rotatable together with the fixed part 62 about the rotation axis Ax4 upon rotation of the fixed part 62. The tool 70 may be attached to the movable part 64. In this case, the orientation of the tool 70 about the rotation axis Ax4 changes as the tool 70 moves up and down. This is therefore useful for adjusting the vertical position of the tool 70 and the orientation of the tool 70 about the rotation axis Ax4 to suit desired control.

[0191] The fourth arm 60 may further include a cover part 68 that covers at least a part of the fixed part 62 from above and moves up and down together with the movable part 64. In this case, even with a configuration in which the tool 70 moves up and down, paint used for painting is less likely to get into the fourth arm 60. Therefore, this is useful for suppressing deterioration of the door opening / closing robot 14 and improving maintainability.

[0192] The arm length L2 of the second arm 40 may be 0.9 to 1.1 times the arm length L1 of the first arm 30. The arm length L3 of the third arm 50 may be 0.9 to 1.1 times the arm length L1 of the first arm 30. If the arm length L1 of the first arm 30 is too large compared to the arm length L2, there is a high possibility that the second arm 40 will interfere with the workpiece W when the first arm 30 is positioned at an angle along the Y-axis direction, assuming that the position of the base 20 is the same. If the arm length L1 is too small compared to the arm length L2, at least one of the arm lengths L2 and L3 must be increased to maintain the same total arm length. If at least one of the arm lengths L2 and L3 is long, when the tool 70 holds the door 260 upstream of the base 20, the connecting portion of the second arm 40 and the third arm 50 will protrude toward the conveyance line Lc, potentially interfering with the workpiece W. In contrast, in the above configuration, the arm lengths are approximately the same, which is useful for avoiding interference between the arms and the workpiece W.

[0193] The bottom surface 22 and the side surface (side surface 24b) of the base 20 may each be attachable to a predetermined position. In this case, the same type of door opening / closing robot 14 can be attached to either the bottom surface 22 or the side surface. This is therefore useful for sharing the door opening / closing robot 14.

[0194] The side surface (side surface 24b) of the base 20 may be attached to a support 208 included in a booth side wall 204 that extends along the conveying line Lc and forms a coating area R for coating workpieces W including the vehicle body 250 and the door 260. In this case, it is easier to raise the tool 70 to a higher position than when the base 20 is fixed to the bottom wall. Therefore, it is useful for working on a vehicle body 250 where the lower end of the window frame 262 is located at a high position.

[0195] The bottom surface 22 of the base 20 may be attached to a booth bottom wall 202 (a part of the booth bottom wall 202) located between the vehicle body 250 being transported along the transport line Lc and a booth side wall 204 extending along the transport line Lc and forming a coating area R for coating the workpiece W including the vehicle body 250 and the door 260. In this case, the bottom surface 22 of the base 20 is supported, so the installation of the base 20 is stable. This is therefore useful for stabilizing the door opening / closing robot 14.

[0196] The base 20 may be disposed between a booth sidewall 204, which extends along the conveying line Lc and forms a coating area R for coating the workpiece W including the vehicle body 250 and the door 260, and the side of the vehicle body 250 being conveyed along the conveying line Lc, and closer to the booth sidewall 204. In this case, a larger space is formed between the base 20 and the side of the vehicle body 250 than between the base 20 and the booth sidewall 204. Therefore, when the workpiece W passes beside the base 20, the arms included in the door opening / closing robot 14 are less likely to interfere with the open door 260. This is useful for simplifying the operation for keeping the door 260 open while following the vehicle body 250.

[0197] The tool 70 may include an extension portion 72 extending in a direction intersecting the vertical direction, and a holding portion 74 extending downward from the extension portion 72 and capable of contacting the inner surface 264 of the door 260. The fourth arm 60 may move the tool 70 in the vertical direction so that the holding portion 74 can pass through the window frame 262 of the door 260 in a state where it is elevated higher than the lower end of the window frame 262 of the door 260. In this case, the inner surface 264 of the door 260 is held by the tool 70, which stabilizes the opening operation of the door 260. This is therefore useful for stabilizing painting work with the door 260 open.

[0198] The example of the door opening / closing system 10 described above includes the door opening / closing robot 14, the transport device 12 that transports the vehicle body 250 along the transport line Lc, and the control device 16 that controls the door opening / closing robot 14 to open and close the door 260 of the vehicle body 250 being transported by the transport device 12. In this case, by working in cooperation with the painting robot, painting can be performed on the vehicle body 250 and the workpiece W including the door 260 with the door 260 open. Therefore, this is useful for automating the work of painting while transporting the vehicle body 250. [Explanation of symbols]

[0199] 1...painting system, W...workpiece, 250...vehicle body, 260...door, 10...door opening / closing system, 12...transport device, Lc...transport line, 14...door opening / closing robot, 16...control device, 18...robot device, 20...base, 22...bottom, 24a to 24d...side, 30, 30B...first arm, 32, 32B...base end, 34, 34B...tip, 40, 40A, 40B...second arm, 42, 42A, 42B...base end part, 44, 44A, 44B...tip part, 50, 50A, 50B...third arm, 52, 52A, 52B...base end part, 54, 54A, 54B...tip part, 60...fourth arm, 62...fixed part, 64...movable part, 68...cover part, 70...tool, 72...extension part, 74...holding part, M1 to M5...motors, Ax1 to Ax4...rotating shafts, R...painting area, 202...bottom wall of booth, 204...side wall of booth, 208...support.

Claims

1. a base provided at a position different from the conveying line along which the vehicle body to be worked on is conveyed; a first arm attached to the base so as to rotate about a first axis along the vertical direction and extending in a direction away from the first axis; a second arm attached to the first arm so as to rotate about a second axis parallel to the first axis and extending in a direction away from the second axis; a third arm attached to the second arm so as to rotate about a third axis parallel to the first axis, the third arm extending in a direction away from the third axis; a fourth arm attached to the third arm at a tip end thereof so as to extend along the up-down direction, the fourth arm moving a tool capable of holding a door attached to the vehicle body along the up-down direction, the second arm is attached below the tip end of the first arm, the third arm is attached to a tip end of the second arm, A door opening and closing robot, wherein at least a portion of the tip of the second arm and at least a portion of the base are positioned at the same height in the vertical direction.

2. 2. The door opening and closing robot according to claim 1, wherein, in the vertical direction, an uppermost position of a portion of the second arm other than the tip end and an uppermost position of a portion of the third arm other than the base end are lower than an uppermost position of the base end of the third arm.

3. 3. The door opening and closing robot according to claim 1, wherein a connection point between the first arm and the second arm and at least a part of a base end of the third arm are located at the same height in the vertical direction.

4. A base provided at a position different from the conveying line along which the vehicle body to be worked on is conveyed; a first arm attached to the base so as to rotate about a first axis along the vertical direction and extending in a direction away from the first axis; a second arm attached to the first arm so as to rotate about a second axis parallel to the first axis and extending in a direction away from the second axis; a third arm attached to the second arm so as to rotate about a third axis parallel to the first axis, the third arm extending in a direction away from the third axis; a fourth arm attached to the third arm at a tip end thereof so as to extend along the up-down direction, the fourth arm moving a tool capable of holding a door attached to the vehicle body along the up-down direction, the second arm is attached below the tip end of the first arm, the third arm is attached below the tip end of the second arm, In the vertical direction, a tip end of the second arm is higher than a base end of the second arm, A door opening and closing robot, wherein at least a portion of a base end of the third arm and at least a portion of the base are positioned at the same height in the vertical direction.

5. A base provided at a position different from the conveying line along which the vehicle body to be worked on is conveyed; a first arm attached to the base so as to rotate about a first axis along the vertical direction and extending in a direction away from the first axis; a second arm attached to the first arm so as to rotate about a second axis parallel to the first axis and extending in a direction away from the second axis; a third arm attached to the second arm so as to rotate about a third axis parallel to the first axis, the third arm extending in a direction away from the third axis; a fourth arm attached to the third arm at a tip end thereof so as to extend along the up-down direction, the fourth arm moving a tool capable of holding a door attached to the vehicle body along the up-down direction, the second arm is attached to a tip end of the first arm, the third arm is attached below the tip end of the second arm, A door opening and closing robot, wherein at least a portion of a base end of the third arm and at least a portion of the base are positioned at the same height in the vertical direction.

6. The door opening and closing robot according to any one of claims 1 to 5, wherein the second arm and the third arm are provided to operate below the door held by the tool.

7. a base provided at a position different from the conveying line along which the vehicle body to be worked on is conveyed; a first arm attached to the base so as to rotate about a first axis along the vertical direction and extending in a direction away from the first axis; a second arm attached to the first arm so as to rotate about a second axis parallel to the first axis and extending in a direction away from the second axis; a third arm attached to the second arm so as to rotate about a third axis parallel to the first axis, the third arm extending in a direction away from the third axis; a fourth arm attached to the third arm at a tip end thereof so as to extend along the up-down direction, the fourth arm moving a tool capable of holding a door attached to the vehicle body along the up-down direction, the second arm is attached below the tip end of the first arm, the third arm is attached to a tip end of the second arm, the fourth arm holds the tool so as to be able to lift and lower the tool so that the tool can pass through a window frame of the door; a connection point between the third arm and the fourth arm is lower than an uppermost position of the second arm and the third arm in the vertical direction; the second arm and the third arm are provided to operate below the door of the vehicle body being transported along the transport line, The door opening and closing robot, wherein at least a portion of the tip of the third arm and at least a portion of the second arm are positioned at the same height in the vertical direction.

8. 8. The door opening and closing robot according to claim 7, wherein a connection point between the first arm and the second arm and at least a part of a base end portion of the third arm are located at the same height in the vertical direction.

9. A base provided at a position different from the conveying line along which the vehicle body to be worked on is conveyed; a first arm attached to the base so as to rotate about a first axis along the vertical direction and extending in a direction away from the first axis; a second arm attached to the first arm so as to rotate about a second axis parallel to the first axis and extending in a direction away from the second axis; a third arm attached to the second arm so as to rotate about a third axis parallel to the first axis, the third arm extending in a direction away from the third axis; a fourth arm attached to the third arm at a tip end thereof so as to extend along the up-down direction, the fourth arm moving a tool capable of holding a door attached to the vehicle body along the up-down direction, the second arm is attached below the tip end of the first arm, the third arm is attached below the tip end of the second arm, In the vertical direction, a tip end of the second arm is higher than a base end of the second arm, the fourth arm holds the tool so as to be able to lift and lower the tool so that the tool can pass through a window frame of the door; a connection point between the third arm and the fourth arm is lower than an uppermost position of the second arm and the third arm in the vertical direction; the second arm and the third arm are provided to operate below the door of the vehicle body being transported along the transport line, The door opening and closing robot, wherein at least a portion of the tip of the third arm and at least a portion of the second arm are positioned at the same height in the vertical direction.

10. A base provided at a position different from the conveying line along which the vehicle body to be worked on is conveyed; a first arm attached to the base so as to rotate about a first axis along the vertical direction and extending in a direction away from the first axis; a second arm attached to the first arm so as to rotate about a second axis parallel to the first axis and extending in a direction away from the second axis; a third arm attached to the second arm so as to rotate about a third axis parallel to the first axis, the third arm extending in a direction away from the third axis; a fourth arm attached to the third arm at a tip end thereof so as to extend along the up-down direction, the fourth arm moving a tool capable of holding a door attached to the vehicle body along the up-down direction, the second arm is attached to a tip end of the first arm, the third arm is attached below the tip end of the second arm, the fourth arm holds the tool so as to be able to lift and lower the tool so that the tool can pass through a window frame of the door; a connection point between the third arm and the fourth arm is lower than an uppermost position of the second arm and the third arm in the vertical direction; the second arm and the third arm are provided to operate below the door of the vehicle body being transported along the transport line, The door opening and closing robot, wherein at least a portion of the tip of the third arm and at least a portion of the second arm are positioned at the same height in the vertical direction.

11. The door opening / closing robot according to any one of claims 1 to 10, wherein the second arm and the third arm are configured to operate below the vehicle body being transported along the transport line.

12. The door opening and closing robot according to claim 1 or 7, wherein a tip end of the third arm is lower than a base end of the third arm in the vertical direction.

13. 13. The door opening and closing robot according to claim 1, wherein the uppermost position of the second arm in the vertical direction is lower than the uppermost position of a lower surface of a portion of the first arm between a base end and a tip end.

14. The door opening and closing robot according to claim 5 or 10, wherein a tip end of the first arm is lower than a base end of the first arm in the vertical direction.

15. The door opening and closing robot according to any one of claims 1 to 14, wherein the first arm is attached to the base.

16. The door opening and closing robot according to any one of claims 1 to 15, wherein at least a portion of the second arm and at least a portion of the base are positioned at the same height in the vertical direction.

17. The door opening / closing robot according to any one of claims 1 to 16, wherein, in the vertical direction, the uppermost position of the tip of the first arm is lower than the lowermost position of the door of the vehicle body being transported along the transport line.

18. In the vertical direction, the uppermost position of the second arm and the uppermost position of the third arm are lower than the lowermost position of the door of the vehicle body being transported along the transport line, In the vertical direction, the lowest positions of the second arm and the third arm are higher than a booth bottom wall on which a conveying device that conveys the vehicle body along the conveying line is provided, The door opening / closing robot according to any one of claims 1 to 17, wherein, in the vertical direction, at least a portion of the base end of the first arm is positioned at the same height as the lowest position of the door of the vehicle body being transported along the transport line.

19. The door opening and closing robot according to any one of claims 1 to 18, wherein the uppermost position of the second arm and the uppermost position of the third arm are lower than the uppermost position of the first arm in the vertical direction.

20. The door opening and closing robot according to any one of claims 1 to 19, wherein the lowest position of the second arm and the lowest position of the third arm are substantially aligned with each other in the vertical direction.

21. The door opening and closing robot according to any one of claims 1 to 20, wherein the base is installed so that the side of the base that is closest to the first axis faces the conveying line when viewed from the vertical direction.

22. a first motor that generates a first driving force for rotating the first arm around the first axis; a second motor that generates a second driving force for rotating the second arm around the second axis, The door opening and closing robot according to any one of claims 1 to 21, wherein the first motor and the second motor are arranged on the first arm.

23. the first motor includes a first motor body and a first output shaft; the second motor includes a second motor body and a second output shaft; the first motor is attached from above with the first output shaft facing downward, The door opening and closing robot according to claim 22, wherein the second motor is attached from above with the second output shaft facing downward.

24. a third motor that generates a third driving force for rotating the third arm around the third axis, The door opening and closing robot according to any one of claims 1 to 23, wherein the third motor is arranged on the second arm such that a distance between the third motor and the second shaft is smaller than a distance between the third motor and the third shaft.

25. the third motor includes a third motor body and a third output shaft; The door opening and closing robot according to claim 24, wherein the third motor is attached from above with the third output shaft facing downward.

26. The door opening and closing robot according to any one of claims 1 to 25, wherein a side portion of the second arm is formed to be recessed inward when viewed from the up-down direction.

27. The door opening and closing robot according to any one of claims 1 to 26, wherein the fourth arm is attached to the tip of the third arm so as to rotate together with the tool around a fourth axis parallel to the first axis.

28. a fourth motor that generates a fourth driving force for rotating the fourth arm around the fourth axis; a fifth motor that generates a fifth driving force for moving the tool along the up-down direction, The door opening and closing robot according to claim 27, wherein the fourth motor and the fifth motor are disposed on the third arm.

29. the fourth motor includes a fourth motor body and a fourth output shaft, the fifth motor includes a fifth motor body and a fifth output shaft, the fourth motor is attached from above with the fourth output shaft facing downward, 29. The door opening and closing robot according to claim 28, wherein the fifth motor is attached from above with the fifth output shaft facing downward.

30. The fourth arm is a first portion attached to a tip end of the third arm and rotatable around the fourth axis; a second part that is rotatable together with the first part about the fourth axis due to the rotation of the first part and is provided on the first part so as to be able to rise and fall; The door opening and closing robot according to any one of claims 27 to 29, wherein the tool is attached to the second part.

31. The door opening and closing robot according to claim 30 , wherein the fourth arm further includes a cover portion that covers at least a part of the first portion from above and moves up and down together with the second portion.

32. the arm length of the second arm is 0.9 to 1.1 times the arm length of the first arm; The door opening and closing robot according to any one of claims 1 to 31, wherein the arm length of the third arm is 0.9 to 1.1 times the arm length of the first arm.

33. The door opening and closing robot according to any one of claims 1 to 32, wherein the bottom surface and the side surface of the base can each be attached to a predetermined position.

34. The door opening / closing robot according to any one of claims 1 to 33, wherein a side surface of the base extends along the conveying line and is attached to a support included in a booth side wall that forms an area for painting workpieces including the vehicle body and the door.

35. A door opening / closing robot as described in any one of claims 1 to 33, wherein the bottom surface of the base is attached to a booth bottom wall located between the vehicle body being transported along the transport line and a booth side wall extending along the transport line and forming an area for painting workpieces including the vehicle body and the door.

36. The door opening / closing robot according to any one of claims 1 to 35, wherein the base extends along the conveying line and is positioned between a booth side wall that forms an area for painting workpieces including the vehicle body and the door and the side of the vehicle body being conveyed along the conveying line, near the booth side wall.

37. The tool includes an extension portion extending along a direction intersecting the vertical direction, and a holding portion extending downward from the extension portion and capable of contacting an inner surface of the door, The door opening and closing robot according to any one of claims 1 to 36, wherein the fourth arm moves the tool along the vertical direction so that the holding portion can pass through the window frame of the door in a state where it is raised above the lower end of the window frame of the door.

38. The door opening and closing robot according to any one of claims 1 to 37, a conveying device that conveys the vehicle body along the conveying line; a control device that controls the door opening / closing robot to open and close the door of the vehicle body being transported by the transport device.

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