Robot system

Abstract

A robot system 100 comprises a robot 1 and a control device 9 that controls the robot 1. The robot 1 has a robot arm 2 that extends and retracts in a predetermined first direction X, a wrist 4 connected to the robot arm 2, and a hand 3 connected to the wrist 4. The wrist 4 moves the hand 3 in a second direction Z that intersects the first direction X. The control device 9 causes the robot 1 to perform an advancing movement of moving the wrist 4 and the hand 3 in the first direction X by extending the robot arm 2 in the first direction X and an elevation movement of moving the hand 3 in the second direction Z by the wrist 4 after the advancing movement.

Description

Robot System

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

[0002] Conventionally, robots having a robot arm and a hand have been known. For example, Patent Document 1 discloses a robot having a hand attached to the tip of a robot arm. This robot uses the hand to pick up workpieces from a parts box arranged on a parts shelf. The robot inserts the hand into a narrow space on the parts shelf. From this state, the hand performs lifting and pitching movements.

[0003] JP 2014-124716 A

[0004] When working in a small space such as the aforementioned shelf, the movement of the robot, for example, the movement of the robot arm, is limited. In an environment where the movement of the robot is limited, the flexibility of the work can be improved by expanding the range of movement of the hand.

[0005] The technology disclosed herein has been made in consideration of the above points, and its purpose is to expand the range of motion of the hand in a small space.

[0006] The robot system of the present disclosure includes a robot and a control device that controls the robot, wherein the robot has a robot arm that extends and retracts in a predetermined first direction, a wrist connected to the robot arm, and a hand connected to the wrist, and the wrist moves the hand in a second direction that intersects with the first direction, and the control device causes the robot to perform an advancing operation that moves the wrist and the hand in the first direction by extending the robot arm in the first direction, and an ascending / descending operation that moves the hand in the second direction using the wrist after the advancing operation.

[0007] According to the robot system, the range of operation of the hand can be expanded in a small space.

[0008] FIG. 1 is a schematic diagram showing a robot system. FIG. 2 is a schematic diagram illustrating the movement of the wrist and hand within a container during a transfer operation. FIG. 3 is a perspective view of the wrist in a basic state. FIG. 4 is a side view of the wrist in a basic state. FIG. 5 is a plan view of the wrist in a basic state. FIG. 6 is a cross-sectional view of the wrist taken along line VI-VI in FIG. 5. FIG. 7 is a side view of the wrist in an advanced state. FIG. 8 is a side view of the wrist when the hand is most advanced in the second direction. FIG. 9 is a perspective view of the wrist when the hand is most advanced in the second direction. FIG. 10 is a side view of the wrist after a pitch motion. FIG. 11 is a side view of the wrist 4 when the hand is most advanced in the second direction and the pitch angle is 90 degrees. FIG. 12 is a perspective view of the wrist after a roll motion. FIG. 13 is a front view of the wrist when the link mechanism has rotated around the roll axis. FIG. 14 is a side view of the wrist after a yaw motion. FIG. 15 is a diagram showing a schematic hardware configuration of a control device. FIG. 16 is a block diagram showing the configuration of a control system of the control device. FIG. 17 is a side view of the hand and wrist during an advancing operation. FIG. 18 is a side view of the hand and wrist during a lifting operation. FIG. 19 is a side view of the hand and wrist before a retreating operation. FIG. 20 is a side view of the hand and wrist after the posture of the hand around the pitch axis has been changed before the advancing operation. FIG. 21 is a front view of the hand and wrist when the rotational posture of the hand during the advancing operation has been changed by a roll operation. FIG. 22 is a front view of the hand and wrist after the link mechanism has rotated around the roll axis. FIG. 23 is a front view of the hand and wrist positioned above the container. FIG. 24 is a front view of the hand and wrist after a roll operation. FIG. 25 is a front view of the hand and wrist after a rectilinear operation. FIG. 26 is a side view of the hand and wrist before a yaw operation when picking adjacent workpieces. FIG. 27 is a side view of the hand and wrist after a yaw operation when picking adjacent workpieces. FIG. 28 is a side view of the hand and wrist with the hand retracted in the second direction while gripping a workpiece. FIG. 29 is a side view of the hand and wrist when the hand gripping the workpiece is rotated around the pitch axis.FIG. 30 is a front view of the hand and wrist when the rotational posture of the hand during a retreating motion is changed by a roll motion.

[0009] Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. In this disclosure, "parallel," "orthogonal," or "identical" not only means "strictly parallel," "orthogonal," or "identical," but also "substantially parallel," "orthogonal," or "identical."

[0010] FIG. 1 is a schematic diagram showing a robot system 100. The robot system 100 includes a robot 1 and a control device 9 that controls the robot 1. For example, the robot 1 performs a transfer operation. Specifically, the robot 1 takes out a workpiece W from a first container C1 placed on a shelf S and transfers the workpiece W to a second container C2. The first container C1 is a source container that stores the workpiece W. The second container C2 is a destination container that stores the workpiece W.

[0011] The shelf S has a plurality of shelf boards s1 arranged at intervals in the vertical direction. The first container C1 is placed on the shelf boards s1. On the shelf S, a work space H is present between the first container C1 and the shelf board s1 located above the first container C1, allowing the robot arm 2 to enter.

[0012] The robot 1 has a robot arm 2 that extends and retracts in a predetermined first direction X, a wrist 4 connected to the robot arm 2, and a hand 3 connected to the wrist 4. The wrist 4 moves the hand 3 in a second direction Z that intersects with the first direction X. A control device 9 uses the robot arm 2 and the wrist 4 to flexibly move the hand 3 in a small space.

[0013] The robot 1 further includes a carriage 11 and an elevator 12 that is disposed on the carriage 11 and supports the robot arm 2 so that the robot arm 2 can move up and down in a predetermined third direction.

[0014] The robot 1 moves by traveling on a carriage 11. The carriage 11 is, for example, an AGV (Automated Guided Vehicle). The carriage 11 includes a box-shaped main body 11a. The main body 11a has at least an upper surface 11b and a recess 11c recessed downward from the upper surface 11b. In this example, a second container C2 is loaded on the upper surface 11b. In other words, the upper surface 11b is a surface on which a container or the like is placed.

[0015] The elevator 12 raises, lowers, and rotates the robot arm 2. The elevator 12 is disposed in the recess 11c. In this example, the elevator 12 has a support column 12a. The support column 12a has an axis extending in the vertical direction. The axis of the support column 12a is also referred to as the lifting axis U. The support column 12a is attached to the carriage 11 so as to be rotatable around the lifting axis U. The support column 12a is disposed in the recess 11c. The support column 12a supports the robot arm 2 so as to be movable along the lifting axis U. The direction of the lifting axis U is the third direction. The elevator 12 lowers the robot arm 2 below the upper surface 11b. The elevator 12 has a linear actuator that moves the robot arm 2 along the lifting axis U, and a rotary actuator that rotates the support column 12a around the lifting axis U. In other words, the elevator 12 moves the robot arm 2 along the lifting axis U using the linear actuator. The elevator 12 rotates the support 12a, and thus the robot arm 2, around an elevator axis U using a rotary actuator.

[0016] The robot arm 2 is a linear-acting telescopic arm. The robot arm 2 telescopes in the direction of a predetermined advance / retract axis V. By telescoping, the robot arm 2 moves the wrist 4 and the hand 3. Specifically, the robot arm 2 has multiple cylindrical arm housings 21. The axis of each arm housing 21 coincides with the advance / retract axis V. The multiple arm housings 21 are nested within each other. The multiple arm housings 21 are movable relative to one another in the direction of the advance / retract axis V. The robot arm 2 has a linear actuator that moves the multiple arm housings 21 relative to one another. By the multiple arm housings 21 moving relatively in the direction of the advance / retract axis V, the robot arm 2 extends and contracts in the direction of the advance / retract axis V. The direction of the advance / retract axis V is the first direction X.

[0017] The robot arm 2 is supported by the elevator 12 with the advance / retract axis V intersecting the lift axis U. Specifically, the advance / retract axis V is perpendicular to the lift axis U. The advance / retract axis V may be disposed at a skewed position relative to the lift axis U.

[0018] The wrist 4 moves the hand 3 in the second direction Z relative to the robot arm 2. The wrist 4 is attached to the tip of the robot arm 2.

[0019] The hand 3 holds the workpiece W. The form of holding by the hand 3 is arbitrary. For example, holding by the hand 3 can be by gripping or suction. In this example, the hand 3 grips the workpiece W. The hand 3 has a hand body 31 and a plurality of fingers 32 attached to the hand body 31. The hand 3 has an actuator that opens and closes the plurality of fingers 32. The hand 3 opens and closes the plurality of fingers 32.

[0020] The robot 1 may further include a camera 15. Note that the camera 15 is only illustrated in FIG. 1 . In this example, the camera 15 is attached to the hand 3, more specifically, to the hand body 31. The camera 15 acquires an image of the inside of the first container C1. The camera 15 acquires an image including a plurality of workpieces W in the first container C1. Here, the image is a two-dimensional image or a three-dimensional image. The three-dimensional image may be point cloud data, an RGB-D image, an RGB image, a depth image, a voxel image, or the like. In other words, the camera 15 may be a three-dimensional camera, i.e., an RGB-D camera that outputs an RGB-D image, a stereo camera that acquires an RGB image, or a three-dimensional vision sensor that acquires point cloud data.

[0021] A transfer operation by the robot 1 will now be briefly described. Fig. 2 is a schematic diagram illustrating the movement of the wrist 4 and hand 3 within the container during the transfer operation. As shown in Fig. 1, the robot 1 moves to a position facing the shelf S by traveling on the cart 11. The elevator 12 moves the robot arm 2 so that the hand 3 is positioned at a position facing the working space H between the target first container C1 and the shelf s1 located above it.

[0022] Next, the robot 1 extends the robot arm 2, causing the robot arm 2 to enter the workspace H. This causes the wrist 4 and the hand 3 to enter the workspace H. The hand 3 is moved to a position above the workpiece W to be picked in the first container C1.

[0023] 2, the robot 1 moves the hand 3 into the first container C1. For example, the robot 1 moves the hand 3 in the second direction Z via the wrist 4, causing the hand 3 to enter the first container C1. Then, the robot 1 grips the workpiece W to be picked with the fingers 32 of the hand 3.

[0024] When the gripping is completed, the robot 1 moves the hand 3 above the first container C1, i.e., to the workspace H. From this state, the robot 1 retracts the robot arm 2 and causes the hand 3 together with the workpiece W to leave the workspace H.

[0025] Thereafter, the elevator 12 rotates and raises and lowers the robot arm 2 to move the hand 3 above the second container C2. The robot 1 moves the hand 3 into the second container C2. The robot 1 places the workpiece W into the second container C2 by releasing the grip of the workpiece W by the fingers 32 of the hand 3.

[0026] In this way, the workpiece W to be picked is transferred from the first container C1 to the second container C2.

[0027] =Wrist= Next, the wrist 4 will be described in detail. Fig. 3 is a perspective view of the wrist 4 in the basic state. Fig. 4 is a side view of the wrist 4 in the basic state. Fig. 5 is a plan view of the wrist 4 in the basic state. Note that the hand 3 is omitted from Figs. 3 and 5.

[0028] The wrist 4 moves the hand 3 linearly in the second direction Z. The wrist 4 includes a first base 41 attached to the robot arm 2, a second base 42 to which the hand 3 is attached, a link mechanism 6 that movably connects the second base 42 to the first base 41, and a first actuator 51 that drives the link mechanism 6. The wrist 4 is attached to the robot arm 2 via the first base 41. The hand 3 is attached to the wrist 4 via the second base 42. The first base 41 and the second base 42 are connected to each other via the link mechanism 6. The first actuator 51 drives the link mechanism 6, causing the second base 42 to move relative to the first base 41. In other words, the hand 3 moves relative to the robot arm 2.

[0029] The link mechanism 6 includes a Chebyshev link mechanism 60 that connects the second base 42 to the first base 41 so as to be linearly movable in a predetermined second direction Z. The first actuator 51 drives a link included in the Chebyshev link mechanism 60 to linearly move the second base 42, i.e., the hand 3, in the second direction Z.

[0030] Here, the linear movement of the second base 42 by the Chebyshev link mechanism 60 is not limited to strictly linear movement, and may be substantially linear movement. In this example, the linear movement of the second base 42 is substantially linear movement along the second direction Z. The second direction Z is a direction intersecting the advance / retraction axis V of the robot arm 2, and more specifically, a direction perpendicular to the advance / retraction axis V. In other words, the wrist 4 linearly moves the hand 3 via the link mechanism 6 in a direction intersecting the advance / retraction direction of the robot arm 2.

[0031] In addition to linear movement, the wrist 4 also performs pitch, roll, and yaw movements. The wrist 4 supports the hand 3 rotatably around a pitch axis P extending in a direction intersecting both the first direction X and the second direction Z. The wrist 4 supports the hand 3 rotatably around a roll axis R extending in the first direction X. More specifically, the wrist 4 is rotatable around the roll axis R. The wrist 4 supports the hand 3 rotatably around a yaw axis Y extending in a direction intersecting the first direction X. Specifically, the wrist 4 further includes a second actuator 52 that rotates the second base 42 around the pitch axis P extending in a direction intersecting the second direction Z, and a pitch transmission mechanism 8 that transmits the driving force of the second actuator to the second base 42. The wrist 4 further includes a third actuator 53 that rotates the second base 42 around the roll axis R extending in a direction intersecting both the pitch axis P and the second direction Z. The wrist 4 further includes a fourth actuator 54 that rotates the hand 3 around a predetermined yaw axis Y, and a yaw transmission mechanism 79 that transmits the driving force of the fourth actuator 54. The basic state of the wrist 4 is a reference state for linear movement, pitch movement, roll movement, and yaw movement.

[0032] =First Base= The first base 41 has a base body 43 attached to the robot arm 2, and a rotating body 44 rotatably connected to the base body 43. The base body 43 is fixed to the tip of the robot arm 2 (in this example, the end opposite the elevator 12). The rotating body 44 is connected to the base body 43 via a bearing so as to be rotatable around a roll axis R. In this example, the roll axis R is parallel to the advance / retract axis V, and more specifically, is aligned in a straight line with the advance / retract axis V. A link mechanism 6 is attached to the rotating body 44.

[0033] = Second Base = The second base 42 has a base body 45 attached to the link mechanism 6, and a rotating body 46 rotatably connected to the base body 45. The rotating body 46 is connected to the base body 45 via a bearing so as to be rotatable around the yaw axis Y. As shown in Figure 4, the hand 3 is attached to the rotating body 46. When the rotating body 46 rotates relative to the base body 45, the hand 3 rotates together with the rotating body 46 around the yaw axis Y relative to the base body 45.

[0034] =Link Mechanism= The link mechanism 6 includes a pair of first and second link mechanisms 6A and 6B arranged to face each other. Each of the first and second link mechanisms 6A and 6B movably connects the second base 42 to the first base 41. Each of the first and second link mechanisms 6A and 6B includes a Chebyshev link mechanism 60. The first and second link mechanisms 6A and 6B have the same configuration. The first and second link mechanisms 6A and 6B perform the same operation to move the second base 42.

[0035] The link mechanism 6 is connected to the first base 41 so as to be rotatable about the roll axis R. More specifically, the link mechanism 6 is attached to the rotating body 44 of the first base 41. When the rotating body 44 rotates about the roll axis R, the link mechanism 6 also rotates about the roll axis R. When the link mechanism 6 rotates about the roll axis R, the hand 3 rotates about the roll axis R together with the second base 42.

[0036] = Chebyshev Link Mechanism = The Chebyshev link mechanism 60 has a driver 61, a follower 62, and an intermediate link 63. The driver 61 is rotatably connected to the first base 41 around a predetermined drive axis D and is driven to rotate. The follower 62 is rotatably connected to the first base 41 around an axis parallel to the drive axis D. The intermediate link 63 is rotatably connected to the driver 61 and the follower 62 around an axis parallel to the drive axis D. More specifically, a shaft 65 is supported on the first base 41 so as to be rotatable about its axis. The rotation axis of the shaft 65 is the drive axis D. The driver 61 is non-rotatably connected to the shaft 65. That is, the driver 61 is rotatably connected to the first base 41 around the drive axis D via the shaft 65. The driver 61 and the shaft 65 are connected to the rotating body 44 of the first base 41. The follower 62 is connected to the rotating body 44 of the first base 41. The rotation axis of the follower 62 is spaced apart from the drive axis D of the driver 61 in a direction parallel to the second direction Z. The second base 42, more specifically, the base main body 45, is connected to the intermediate link 63. The follower 62 is connected to a portion of the intermediate link 63 between the portion to which the driver 61 is connected and the portion to which the second base 42 is connected. When the driver 61 is rotationally driven, the follower 62 and intermediate link 63 move in conjunction with each other, and the second base 42 moves.

[0037] In the Chebyshev link mechanism 60, the link length of each link is appropriately set, so that the portion of the intermediate link 63 connected to the second base 42 moves approximately linearly in response to the rotation of the driver 61. Specifically, if the link length of the driver 61 is 1, the link length of the follower 62 is 2.5, the distance between the connecting portion of the driver 61 and the connecting portion of the follower 62 in the intermediate link 63 is 2.5, the distance between the connecting portion of the follower 62 and the connecting portion of the second base 42 in the intermediate link 63 is 2.5, and the distance between the drive axis D of the driver 61 and the rotation axis of the follower 62 is 2. As a result, when the driver 61 is rotationally driven, the portion of the intermediate link 63 connected to the second base 42, i.e., the second base 42, moves linearly. The direction of movement of the second base 42 substantially coincides with the second direction Z.

[0038] The first link mechanism 6A and the second link mechanism 6B face each other in the direction of the drive axis D. That is, the opposing direction of the first link mechanism 6A and the second link mechanism 6B coincides with the direction of the drive axis D. In the direction of the drive axis D, the driver 61 of the first link mechanism 6A faces the driver 61 of the second link mechanism 6B, the follower 62 of the first link mechanism 6A faces the follower 62 of the second link mechanism 6B, and the intermediate link 63 of the first link mechanism 6A faces the intermediate link 63 of the second link mechanism 6B.

[0039] More specifically, each of the two mutually connected joints in the link mechanism overlaps in the direction of the drive axis D at the joint, and therefore are disposed at offset positions in the direction of the drive axis D. As shown in FIG. 5 , the driver 61 of the first link mechanism 6A is disposed inward of the intermediate joint 63 of the first link mechanism 6A in the opposing direction between the first link mechanism 6A and the second link mechanism 6B. The driver 61 of the second link mechanism 6B is disposed inward of the intermediate joint 63 of the second link mechanism 6B in the opposing direction between the first link mechanism 6A and the second link mechanism 6B. That is, the driver 61 of the first link mechanism 6A and the driver 61 of the second link mechanism 6B are disposed between the intermediate joint 63 of the first link mechanism 6A and the intermediate joint 63 of the second link mechanism 6B. Of the joints of the first link mechanism 6A and the second link mechanism 6B, the intermediate joint 63 of the first link mechanism 6A and the intermediate joint 63 of the second link mechanism 6B are disposed outermost in the opposing direction.

[0040] The driving link 61 of the first link mechanism 6A and the driving link 61 of the second link mechanism 6B are connected to a common shaft 65 .

[0041] The intermediate link 63 of the first link mechanism 6A and the intermediate link 63 of the second link mechanism 6B are connected to each other. Specifically, as shown in Fig. 5, the joint 64a connecting the driver link 61 and the intermediate link 63 of the first link mechanism 6A and the joint 64a connecting the driver link 61 and the intermediate link 63 of the second link mechanism 6B are connected to each other. More specifically, the joint 64a of the first link mechanism 6A and the joint 64a of the second link mechanism 6B are connected to each other via a shaft 66 extending parallel to the drive axis D. The driver link 61 and the intermediate link 63 of the first link mechanism 6A are rotatably connected to one end of the shaft 66. The driver link 61 and the intermediate link 63 of the second link mechanism 6B are rotatably connected to the other end of the shaft 66.

[0042] =First Actuator= The first actuator 51 is an electric motor, specifically a servo motor. The first actuator 51 is provided with an encoder. The first actuator 51 is attached to the first base 41, more specifically, to the rotating body 44. As shown in FIG. 5 , the first actuator 51 is disposed between the first link mechanism 6A and the second link mechanism 6B.

[0043] FIG. 6 is a cross-sectional view of the wrist 4 taken along line VI-VI in FIG. 5. The rotation of the first actuator 51 is transmitted to the Chebyshev link mechanism 60 via a linear transmission mechanism 71. The linear transmission mechanism 71 includes a worm gear. Specifically, the linear transmission mechanism 71 includes a worm 72 attached to the output shaft of the first actuator 51 and a worm wheel 73 connected to the driver 61 of the Chebyshev link mechanism 60 and meshing with the worm 72. The worm 72 rotates integrally with the output shaft. The worm wheel 73 is non-rotatably attached to the shaft 65. That is, the worm wheel 73 is connected to the driver 61 via the shaft 65.

[0044] When the first actuator 51 operates, the worm 72 rotates. The worm wheel 73 rotates in conjunction with the worm 72, and the shaft 65 rotates integrally with the worm wheel 73. Because the driver 61 is non-rotatably connected to the shaft 65, the driver 61 rotates integrally with the shaft 65 around the drive axis D. In this manner, the Chebyshev link mechanism 60 is driven by the first actuator 51. Because the driver 61 of both the first link mechanism 6A and the second link mechanism 6B is connected to the shaft 65, the Chebyshev link mechanism 60 of the first link mechanism 6A and the Chebyshev link mechanism 60 of the second link mechanism 6B operate integrally.

[0045] =Linear Movement= The movement of the wrist 4 by the Chebyshev link mechanism 60 will be described in detail. Fig. 7 is a side view of the wrist 4 in an advanced state. Fig. 8 is a side view of the wrist 4 in a state in which the hand 3 has advanced to the most advanced position in the second direction Z. Fig. 9 is a perspective view of the wrist 4 in a state in which the hand 3 has advanced to the most advanced position in the second direction Z. Note that the hand 3 is omitted from Fig. 9. The advanced state of the wrist 4 is a state in which the wrist 4 has moved from the basic state in the second direction Z.

[0046] In the Chebyshev link mechanism 60, in a certain section (hereinafter referred to as the "specific section") of one rotation of the driver 61, the tip of the intermediate link 63, i.e., the end of the intermediate link 63 opposite the end to which the driver 61 is connected, moves substantially linearly. The direction of movement of the tip of the intermediate link 63 substantially coincides with the second direction Z. Specifically, the tip of the intermediate link 63 moves linearly between a first position and a second position in the second direction Z. The second position is farther from the drive axis D of the driver 61 in the second direction Z than the first position. In other words, movement of the intermediate link 63 toward the second position in the second direction Z is movement away from the drive axis D of the driver 61, and is also referred to as "advancing." Movement of the intermediate link 63 toward the first position in the second direction Z is movement toward the drive axis D of the driver 61, and is also referred to as "retreating." In the basic state of the wrist 4, the tip of the intermediate link 63 is located at the first position. The positions of the second base 42, the hand 3, etc. when the tip of the intermediate link 63 is located at the first position are also referred to as the "first position." The positions of the second base 42, the hand 3, etc. when the tip of the intermediate link 63 is located at the second position are also referred to as the "second position." For example, the first position of the hand 3 is the position of the hand 3 when the tip of the intermediate link 63 is located at the first position.

[0047] When the driver 61 is in the state shown in FIG. 4 , the tip of the intermediate link 63 is located at the first position. Note that the tip of the intermediate link 63 is also located at the first position in FIGS. 3 and 5 . When the driver 61 rotates clockwise (in the direction of the arrow in the figure) from the state shown in FIG. 4 , the tip of the intermediate link 63 moves linearly in the second direction Z toward the second position (downward in the figure), as shown in FIG. 7 . When the driver 61 reaches the state shown in FIG. 8 , the tip of the intermediate link 63 reaches the second position in the second direction Z. When the driver 61 rotates counterclockwise from the state shown in FIG. 8 , the tip of the intermediate link 63 moves linearly in the second direction Z toward the first position. When the driver 61 reaches the state shown in FIG. 4 , the tip of the intermediate link 63 reaches the first position in the second direction Z.

[0048] 8 to the state shown in FIG. 4, the tip of the intermediate link 63 also returns to the first position. However, the trajectory of the tip of the intermediate link 63 at this time is not linear but curved.

[0049] In this way, in a specific section of rotation of the driver 61, the tip of the intermediate link 63 moves linearly. The second base 42 is connected to the tip of the intermediate link 63, and the hand 3 is attached to the second base 42. In other words, the hand 3 moves linearly. By rotating the driver 61 within the specific section, the hand 3 can be effectively moved forward and backward in the second direction Z. Depending on the direction of rotation of the driver 61 in this specific section, it is determined whether the tip of the intermediate link 63, i.e., the hand 3, moves toward the first position or the second position in the second direction Z.

[0050] =Pitch Transmission Mechanism= The second base 42 is connected to the intermediate link 63 so as to be rotatable around the pitch axis P. Specifically, as shown in FIG. 3 , the intermediate link 63 of the first link mechanism 6A and the intermediate link 63 of the second link mechanism 6B face each other in the direction of the drive axis D. The second base 42 is connected to the two intermediate links 63 so as to be rotatable around the pitch axis P. The pitch axis P is parallel to the drive axis D. In other words, the pitch axis P is perpendicular to the plane in which each link of the link mechanism 6 moves. The pitch transmission mechanism 8 is connected to the second base 42. The second base 42 includes a rotor 46 that is rotatable around the yaw axis Y. The yaw axis Y extends in a direction intersecting the direction of the pitch axis P.

[0051] As shown in FIG. 4, the pitch transmission mechanism 8 includes a four-bar link mechanism 80. The four-bar link mechanism 80 is a parallel link mechanism. The intermediate link 63 of the Chebyshev link mechanism 60 functions as a node included in the four-bar link mechanism 80. In this example, as shown in FIG. 5, the pitch transmission mechanism 8 includes a four-bar link mechanism 80 corresponding to the first link mechanism 6A and a four-bar link mechanism 80 corresponding to the second link mechanism 6B. The four-bar link mechanism 80 corresponding to the first link mechanism 6A and the four-bar link mechanism 80 corresponding to the second link mechanism 6B have the same configuration.

[0052] 4 , the four-bar link mechanism 80 includes a first four-bar link mechanism 81 connected to the second base 42, and a second four-bar link mechanism 82 connected to the first four-bar link mechanism 81 and driven by the second actuator 52. The intermediate link 63 of the Chebyshev link mechanism 60 functions as a node included in the first four-bar link mechanism 81, and the driven link 62 of the Chebyshev link mechanism 60 functions as a node included in the second four-bar link mechanism 82.

[0053] Specifically, the first four-link linkage 81 includes a first fixed link 83, a first driver link 84 rotatably connected to the first fixed link 83 about an axis parallel to the pitch axis P, a first follower link 85 rotatably connected to the first fixed link 83 about an axis parallel to the pitch axis P, and a first intermediate link 86 rotatably connected to each of the first driver link 84 and the first follower link 85 about an axis parallel to the pitch axis P. The first fixed link 83 is the intermediate link 63 of the Chebyshev linkage 60. The first follower link 85 is fixed to the second base 42. More specifically, the first follower link 85 is part of the base body 45 of the second base 42. The first intermediate link 86 is disposed opposite the first fixed link 83. The first four-link linkage 81 is a parallel linkage. The four joints connecting the first fixed link 83, the first driving link 84, the first driven link 85 and the first intermediate link 86 are arranged substantially at the vertices of a parallelogram.

[0054] The second four-link linkage 82 includes a second fixed link 87, a second driver link 88 rotatably connected to the second fixed link 87 about an axis parallel to the pitch axis P, a second follower link 89 rotatably connected to the second fixed link 87 about an axis parallel to the pitch axis P, and a second intermediate link 810 rotatably connected to each of the second driver link 88 and the second follower link 89 about an axis parallel to the pitch axis P. The second fixed link 87 is the follower link 62 of the Chebyshev linkage 60. The second intermediate link 810 is located opposite the second fixed link. The second four-link linkage 82 is a parallel linkage. The four joints connecting the second fixed link 87, the second driver link 88, the second follower link 89, and the second intermediate link 810 are located substantially at the vertices of a parallelogram.

[0055] 4, dashed lines indicate straight line segments that define the link lengths of the first four-bar link mechanism 81 and the second four-bar link mechanism 82. The same applies to FIGS.

[0056] The second follower 89 is connected to the first driver 84. The second follower 89 is connected to the first driver 84 via a connecting joint 811. When the second follower 89 moves, the first driver 84 moves in conjunction with the second follower 89. More specifically, both the first driver 84 and the second follower 89 are connected to the connecting portion between the follower 62 and the intermediate joint 63. The first driver 84, the second follower 89, and the connecting joint 811 are integrally formed. The relative positions of the first driver 84, the second follower 89, and the connecting joint 811 are fixed. In this example, the first driver 84, the second follower 89, and the connecting joint 811 are formed of substantially triangular plates. When the second follower 89 moves, the first driver 84 and the connecting joint 811 move in conjunction with the second follower 89.

[0057] The second driver 88 is rotationally driven by the second actuator 52. As shown in FIG. 6 , a shaft 812 that is rotationally driven by the second actuator 52 is coupled to the second driver 88. More specifically, the shaft 812 is supported on the first base 41 so as to be rotatable about its axis. The rotation axis E of the shaft 812, i.e., the axis, is parallel to the drive axis D. The second driver 88 is non-rotatably coupled to the shaft 812. That is, the second driver 88 is coupled to the first base 41 via the shaft 812 so as to be rotatable about the rotation axis E. The second driver 88 and the shaft 812 are coupled to the rotating body 44 of the first base 41. The follower 62 is coupled to the shaft 812 so as to be rotatable about the rotation axis E. That is, the follower 62 is rotatably coupled to the first base 41 and the second driver 88 via the shaft 812.

[0058] When the shaft 812 is driven to rotate, the second driver 88 rotates integrally with the shaft 812. On the other hand, the follower 62 does not rotate integrally with the shaft 812. When the second driver 88 rotates, the second intermediate link 810 and the second follower 89 move in conjunction with the rotation of the second driver 88. When the second follower 89 moves, the first driver 84 of the first four-link linkage 81 rotates in conjunction with the second follower 89. When the first driver 84 rotates, the first intermediate link 86 and the first follower 85 move in conjunction with the rotation of the first driver 84. Because the first follower 85 is formed integrally with the second base 42, the second base 42 rotates around the pitch axis P. Note that the rotation of the second driver 88 does not affect the first fixed link 83 and the second fixed link 87, i.e., the Chebyshev linkage 60.

[0059] In this way, when the second driving link 88 is rotationally driven, the second base 42 and the hand 3 rotate around the pitch axis P without affecting the Chebyshev link mechanism 60 .

[0060] = Second Actuator = The second actuator 52 is an electric motor, specifically a servo motor. The second actuator 52 is provided with an encoder. As shown in FIG. 5 , the second actuator 52 is attached to the first base 41, more specifically, to the rotating body 44. The second actuator 52 is disposed between the first link mechanism 6A and the second link mechanism 6B.

[0061] The rotation of the second actuator 52 is transmitted to the four-bar linkage 80 via a worm gear. Specifically, as shown in FIG. 6 , a worm 74 is attached to the output shaft of the second actuator 52. The worm 74 rotates integrally with the output shaft. A worm wheel 75 is connected to a second driver link 88 of the four-bar linkage 80. The worm wheel 75 is attached to a shaft 812 so as not to rotate. In other words, the worm wheel 75 is connected to the second driver link 88 via the shaft 812. The worm 74 and the worm wheel 75 mesh with each other.

[0062] When the second actuator 52 operates, the worm 74 rotates. The worm wheel 75 rotates in conjunction with the worm 74, and the shaft 812 rotates integrally with the worm wheel 75. Because the second driver 88 is non-rotatably connected to the shaft 812, the second driver 88 rotates integrally with the shaft 812 around the rotation axis E. In this manner, the four-bar linkage 80 is driven by the second actuator 52. Because the second driver 88 of the four-bar linkage 80 corresponding to the first linkage 6A and the second driver 88 of the four-bar linkage 80 corresponding to the second linkage 6B are connected to the shaft 812, the second driver 88 of the two four-bar linkages 80 operate integrally.

[0063] =Pitch Movement= Next, the pitch movement of the wrist 4 will be described. Figure 10 is a side view of the wrist 4 after the pitch movement. In Figure 10, the wrist 4 is rotated around the pitch axis P from the basic state in Figure 4. In this example, the pitch angle is set to 0 degrees when the fingers 32 extend in the second direction Z, that is, when the yaw axis Y points in the second direction Z. The direction in which the tips of the fingers 32 rotate away from the first base 41 from a state in which the pitch angle is 0 degrees is set to positive. The hand 3 in Figure 10 has rotated approximately 90 degrees around the pitch axis P.

[0064] When the Chebyshev link mechanism 60 is not moving, the follower 62 (i.e., the second fixed link 87) and the intermediate link 63 (i.e., the first fixed link 83) do not move. When the second driver 88 is rotationally driven by the second actuator 52, the second intermediate link 810 and the second follower 89 move in conjunction with the second driver 88. Because the relative positional relationship between the first driver 84 and the second follower 89 remains unchanged, the first driver 84 rotates in conjunction with the movement of the second follower 89. When the first driver 84 rotates, the first intermediate link 86 and the first follower 85 move in conjunction with the first driver 84. The first follower 85 rotates around the pitch axis P. The first follower 85 is integrally formed with the second base 42, and the hand 3 is attached to the second base 42. In other words, the hand 3 rotates around the pitch axis P. The pitch angle, which is the angle of the second base 42 around the pitch axis P, is adjusted by the rotation angle of the second driving link 88.

[0065] When the Chebyshev link mechanism 60 operates, the follower 62 and the intermediate link 63 move, and therefore the four-bar link mechanism 80 also moves. However, when the second driver 88 is not rotationally driven, the angle of the first follower 85 does not change, and the pitch angle of the hand 3 is maintained, as shown in FIGS. 4, 7, and 8 . In other words, the pitch transmission mechanism 8 maintains the pitch angle of the second base 42 about the pitch axis P when the second base 42 moves in the second direction Z via the Chebyshev link mechanism 60. The orientation of the first driver 84, which is a node located opposite the first follower 85, which is a node integral with the second base 42, is maintained and does not change during operation of the Chebyshev link mechanism 60.

[0066] Specifically, because the second four-bar link mechanism 82 is a parallel link mechanism, the angle between the opposing second driver 88 and second follower 89 does not change in FIGS. 4, 7, and 8. In other words, if the second driver 88 does not rotate, the angle of the second follower 89 does not change even if the second follower 89 moves. Furthermore, because the second follower 89 and the first driver 84 are integrally connected, the relative positional relationship between the second follower 89 and the first driver 84 does not change. In other words, if the angle of the second follower 89 does not change, the angle of the first driver 84 does not change even if the first driver 84 moves. Furthermore, because the first four-bar link mechanism 81 is a parallel link mechanism, the angle between the opposing first driver 84 and first follower 85 does not change. In other words, if the angle of the first driver 84 does not change, the angle of the first follower 85 does not change even if the first driver 84 moves. In short, even if the second follower 89, the first driver 84, and the first follower 85 move in accordance with the operation of the Chebyshev link mechanism 60, unless the second driver 88 rotates, the angles of the second follower 89, the first driver 84, and the first follower 85 do not change.

[0067] In other words, the pitch angle of the hand 3 depends on the rotation angle of the second driver 88 and is not affected by the state of the Chebyshev link mechanism 60. Whether the Chebyshev link mechanism 60 is stopped or operating, when the second driver 88 is rotationally driven, the pitch angle of the hand 3 changes according to the rotation angle of the second driver 88. Whether the Chebyshev link mechanism 60 is stopped or operating, when the second driver 88 is not rotating, the pitch angle of the hand 3 is maintained.

[0068] In the pitch transmission mechanism 8, the shaft 812 is connected to the second driver link 88. Therefore, as shown in FIG. 11 , depending on the state of the pitch transmission mechanism 8, the second intermediate link 810 approaches the shaft 812. FIG. 11 is a side view of the wrist 4 when the hand 3 is most advanced in the second direction Z and the pitch angle is 90 degrees. The second intermediate link 810 is curved to avoid interference with the shaft 812 when it approaches the shaft 812 in conjunction with the second driver link 88. In other words, when the angle between the second driver link 88 and the second fixed link 87 is large, the second intermediate link 810 approaches the shaft 812. The second intermediate link 810 has a curved portion 810 a at a portion approaching the shaft 812 that is curved so as to be recessed toward the side away from the shaft 812. The curved portion 810 a of the second intermediate link 810 makes it less likely for the second intermediate link 810 to interfere with the shaft 812. This increases the range of motion of the second intermediate section 810, and as a result, the range of pitch motion of the wrist 4 is increased.

[0069] =Third Actuator= The third actuator 53 is an electric motor, specifically a servo motor. The third actuator 53 is provided with an encoder. As shown in FIG. 5 , the third actuator 53 is attached to the first base 41, more specifically, to the base main body 43.

[0070] The rotation of the third actuator 53 is transmitted to the rotating body 44 via a roll transmission mechanism 76. The roll transmission mechanism 76 includes a gear train. Specifically, the roll transmission mechanism 76 includes a first gear 77 attached to the output shaft of the third actuator 53 and a second gear 78 attached to the rotating body 44. The first gear 77 rotates integrally with the output shaft. The second gear 78 is attached to the rotating body 44 so as to be non-rotatable. The second gear 78 meshes with the first gear 77.

[0071] =Rolling Motion= Next, the rolling motion of the wrist 4 will be described. Figure 12 is a perspective view of the wrist 4 after the rolling motion. In Figure 12, the link mechanism 6 is rotated around the roll axis R from the basic state in Figure 4. In this example, the roll angle is defined as 0 degrees when the second direction Z extends vertically and the fingers 32 extend downward from the hand body 31. The clockwise direction when viewed facing the first base 41 in the direction of the roll axis R is defined as positive. The link mechanism 6 in Figure 12 has rotated approximately 90 degrees around the roll axis R.

[0072] When the third actuator 53 operates, the first gear 77 rotates. The second gear 78 rotates in conjunction with the first gear 77, and the rotating body 44 rotates integrally with the second gear 78 around the roll axis R. The link mechanism 6 is connected to the rotating body 44. The link mechanism 6 is connected to the second base 42. In this way, the third actuator 53 rotates the second base 42 around the roll axis R. Since the hand 3 is connected to the second base 42, the hand 3 rotates around the roll axis R. The pitch transmission mechanism 8 also rotates integrally with the rotating body 44 around the roll axis R.

[0073] 13 is a front view of the wrist 4 with the link mechanism 6 rotated about the roll axis R. Because the link mechanism 6 rotates about the roll axis R, the second direction Z and the pitch axis P also rotate about the roll axis R. In other words, by rotating the link mechanism 6 about the roll axis R, the direction in which the hand 3 moves linearly can be changed, and the direction of the pitch axis P of the pitch movement of the wrist 4 can also be changed.

[0074] =Fourth Actuator= The fourth actuator 54 is an electric motor, specifically a servo motor. The fourth actuator 54 is provided with an encoder. As shown in FIG. 3 , the fourth actuator 54 is attached to the second base 42, more specifically, to the base main body 45. The fourth actuator 54 is disposed between the first link mechanism 6A and the second link mechanism 6B.

[0075] =Yaw Transmission Mechanism= The rotation of the fourth actuator 54 is transmitted to the rotating body 46 via a yaw transmission mechanism 79. The yaw transmission mechanism 79 includes a transmission belt and a worm gear. Specifically, a shaft 47 is supported on the base main body 45 so as to be rotatable about its axis. The yaw transmission mechanism 79 includes a pulley attached to the output shaft of the fourth actuator 54, a pulley attached to the shaft 47, a belt wound around the two pulleys, a worm 710 attached to the shaft 47, and a worm wheel 711 attached to the rotating body 46. The worm 710 is non-rotatably attached to the shaft 47 and rotates integrally with the shaft 47. The worm wheel 711 is non-rotatably attached to the rotating body 46 and meshes with the worm 710. The yaw axis Y passes through the center of the worm wheel 711.

[0076] When the fourth actuator 54 operates, the shaft 47 rotates via the two pulleys and the belt. The worm 710 rotates together with the shaft 47, and the worm wheel 711 rotates in conjunction with the worm 710. The rotating body 46 rotates integrally with the worm wheel 711.

[0077] = Yaw Movement = Next, the yaw movement of the wrist 4 will be described. Fig. 14 is a side view of the wrist 4 after the yaw movement. In Fig. 14, the wrist 4 rotates the hand 3 around the yaw axis Y from the basic state in Fig. 4. In this example, the yaw angle is set to 0 degrees when the opening and closing direction of the fingers 32 is parallel to the roll axis R. The hand 3 in Fig. 14 has rotated approximately 90 degrees around the yaw axis Y.

[0078] When the fourth actuator 54 rotates the rotating body 46 about the yaw axis Y, the hand 3 rotates integrally with the rotating body 46 about the yaw axis Y. When the wrist 4 performs a yaw movement, the opening and closing directions of the fingers 32 change. In FIG. 4 , the opening and closing directions of the fingers 32 are parallel to the roll axis R. On the other hand, in FIG. 14 , the opening and closing directions of the fingers 32 are perpendicular to the roll axis R.

[0079] Furthermore, since the hand 3 is supported on the second base 42 so as to be rotatable around the yaw axis Y, when the second base 42 moves by roll and / or pitch movement, the direction of the yaw axis Y also changes according to the second base 42.

[0080] =Controller= Fig. 15 is a diagram showing a schematic hardware configuration of the controller 9. The controller 9 controls the robot 1 to cause the hand 3 to perform various tasks. The robot system 100 further includes a robot controller 10. The controller 9 transmits and receives signals, information, etc. to and from the robot controller 10. The controller 9 controls the robot 1 via the robot controller 10. The controller 9 outputs commands to the robot controller 10. The controller 9 transmits and receives signals, information, etc. to and from the camera 15. The robot controller 10 controls various actuators of the robot 1 in accordance with commands from the controller 9.

[0081] The robot control device 10 includes a processor 101 , a storage device 102 , and a memory 103 .

[0082] The processor 101 controls the entire robot control device 10. The processor 101 performs various types of arithmetic processing. For example, the processor 101 is formed of a processor such as a CPU (Central Processing Unit). The processor 101 may also be formed of an MCU (Micro Controller Unit), an MPU (Micro Processor Unit), an FPGA (Field Programmable Gate Array), a PLC (Programmable Logic Controller), a system LSI, or the like.

[0083] The storage unit 102 stores programs and various data to be executed by the processor 101. The storage unit 102 is formed of a non-volatile memory, a hard disk drive (HDD), a solid state drive (SSD), or the like. The memory 103 temporarily stores data and the like. For example, the memory 103 is formed of a volatile memory.

[0084] The processor 101 controls the carriage 11, the elevator 12, the robot arm 2, the hand 3, and the wrist 4 based on commands from the control device 9. Specifically, the processor 101 controls the actuators of the carriage 11, etc. At this time, the robot control device 10 controls each actuator.

[0085] The control device 9 includes a processor 91 , a storage device 92 , and a memory 93 .

[0086] The processor 91 controls the entire control device 9. The processor 91 performs various types of arithmetic processing. For example, the processor 91 is formed of a processor such as a CPU (Central Processing Unit). The processor 91 may be formed of an MCU (Micro Controller Unit), an MPU (Micro Processor Unit), an FPGA (Field Programmable Gate Array), a PLC (Programmable Logic Controller), a system LSI, or the like.

[0087] The storage unit 92 stores various programs and various data executed by the processor 91. The storage unit 92 is formed of a non-volatile memory, a hard disk drive (HDD), a solid state drive (SSD), or the like. The various programs cause the control device 9 to realize various functions. The memory 93 temporarily stores data and the like. For example, the memory 93 is formed of a volatile memory. The memory 93 stores images from the camera 15.

[0088] 16 is a block diagram showing the configuration of the control system of the control device 9. The processor 91 realizes various functions by reading out a program from the storage device 92 into the memory 93 and expanding the program. Specifically, the processor 91 functions as a travel controller 94, an operation controller 95, a detector 96, and a determiner 97.

[0089] The travel controller 94 controls the carriage 11. The travel controller 94 controls the travel of the carriage 11 to move the robot 1.

[0090] The motion controller 95 operates the elevator 12, the robot arm 2, the hand 3, and the wrist 4. The motion controller 95 controls the actuators of the elevator 12, the robot arm 2, the hand 3, and the wrist 4. For example, the motion controller 95 raises, lowers, and rotates the elevator 12. The motion controller 95 extends and retracts the robot arm 2. The motion controller 95 opens and closes the fingers 32 of the hand 3. The motion controller 95 causes the wrist 4 to perform various motions.

[0091] The detector 96 causes the camera 15 to acquire an image of the inside of the first container C1 and detects the workpiece W from the acquired image. The detector 96 causes the camera 15 to acquire an image after the hand 3 is positioned above the first container C1 by the robot arm 2. The camera 15 photographs the inside of the first container C1 from above. The detector 96 stores the image from the camera 15 in the memory 93. The detector 96 detects the workpiece W from the image by image recognition. The image may include multiple workpieces. The detector 96 detects the position, size, etc. of the workpiece W.

[0092] The determinator 97 determines whether the hand 3 will interfere with another object during operation of the robot 1. When the hand 3 holds a workpiece W, the determinator 97 determines whether the workpiece W held by the hand 3 will interfere with another object. In this example, the determinator 97 determines whether the hand 3 or the workpiece W will interfere with the first container C1 when the hand 3 moves. Specifically, the determinator 97 estimates whether the hand 3 or the workpiece W will interfere with the first container C1 based on the position of the hand 3, the posture of the hand 3, the size of the workpiece W, etc.

[0093] Next, the basic operations of the transfer operation by the robot 1 will be described. The transfer operation includes a picking operation and a placing operation. The control device 9, specifically the travel controller 94, controls the cart 11 to move the robot 1 to a position facing the shelf S, as shown in FIG. 1 . The control device 9, specifically the motion controller 95, controls the elevator 12 to move the robot arm 2 so that the hand 3 is positioned at a predetermined approach start position. The approach start position is a position where the hand 3 faces the workspace H between the target first container C1 and the shelf s1 located above it.

[0094] From this state, the control device 9, specifically the motion controller 95, causes the robot 1 to perform an advancing operation and an elevating operation. FIG. 17 is a side view of the hand 3 and wrist 4 during the advancing operation. FIG. 18 is a side view of the hand 3 and wrist 4 during the elevating operation. In the advancing operation, as shown in FIG. 17 , the robot 1 extends the robot arm 2 in the first direction X to move the hand 3 and wrist 4 in the first direction X. The hand 3 and wrist 4 enter the workspace H from the first direction X. A portion of the robot arm 2 also enters the workspace H from the first direction X. At this time, the wrist 4 positions the hand 3 at the first position in the second direction Z. This makes the hand 3 and wrist 4 compact in the second direction Z, facilitating the entry of the hand 3 and wrist 4 into the workspace H. In this example, the fingers 32 of the hand 3 are facing the second direction Z. The orientation of the finger 32 is the direction in which the finger 32 extends, which is the direction of the yaw axis Y in this example.

[0095] The control device 9, specifically the motion controller 95, causes the robot 1 to perform an elevation operation after the advance operation. In the elevation operation, as shown in FIG. 18 , the robot 1 moves the hand 3 by the wrist 4 in the second direction Z away from the robot arm 2, i.e., advances. The hand 3 advances into the first container C1. Specifically, the control device 9 operates the first actuator 51 to operate the Chebyshev link mechanism 60. The wrist 4 moves the hand 3 linearly in the second direction Z. This allows the hand 3 to reach the target workpiece W.

[0096] In this example, the robot 1 does not move the robot arm 2 during the lifting operation. However, the position of the robot arm 2 may be adjusted by extending or contracting the robot arm 2, rotating the robot arm 2 using the elevator 12, or moving the cart 11 before or during the lifting operation.

[0097] The control device 9, specifically the detector 96, may cause the camera 15 to acquire an image of the inside of the first container C1 between the advancing operation and the lifting operation. The detector 96 detects the position of the workpiece W from the acquired image. The operation controller 95 may adjust the position of the hand 3 by moving the robot arm 2 based on the detected position of the workpiece W. The operation controller 95 may adjust the position of the hand 3 by moving the cart 11 or the elevator 12 based on the detected position of the workpiece W.

[0098] After the lifting operation, the control device 9, specifically the motion controller 95, causes the robot 1 to perform a holding operation and a retreating operation. In the holding operation, the robot 1 causes the hand 3 to hold the workpiece W. The hand 3 grips the workpiece W by closing the fingers 32.

[0099] The control device 9, specifically the motion controller 95, causes the robot 1 to perform a lifting / lowering motion after the holding motion and before the retreating motion. In the lifting / lowering motion, the robot 1 moves the hand 3 by the wrist 4 toward the robot arm 2 in the second direction Z, i.e., retreats. The hand 3 leaves the first container C1. Specifically, the control device 9 operates the first actuator 51 and the Chebyshev link mechanism 60. The wrist 4 moves the hand 3 linearly in the second direction Z to the first position. In this example, the robot 1 does not move the robot arm 2 in the lifting / lowering motion.

[0100] FIG. 19 is a side view of the hand 3 and wrist 4 before performing a retreating motion. The control device 9, specifically the motion controller 95, causes the robot 1 to perform a retreating motion after the lifting motion. During the retreating motion, the robot 1 moves the hand 3 and wrist 4 in the first direction X by retracting the robot arm 2 in the first direction X. The hand 3 and wrist 4 retract from the workspace H in the first direction X. A portion of the robot arm 2 also retracts from the workspace H in the first direction X. The wrist 4 positions the hand 3 at the first position in the second direction Z. This makes the hand 3 and wrist 4 compact in the second direction Z, facilitating the retraction of the hand 3 and wrist 4 from the workspace H. In this example, the fingers 32 of the hand 3 are facing the second direction Z.

[0101] For the placing operation, the control device 9 moves the hand 3 above the second container C2 by rotating and raising and lowering the elevator 12. If necessary, the control device 9 adjusts the position of the hand 3 relative to the second container C2 by extending the robot arm 2. The control device 9 moves the hand 3 into the second container C2 by the wrist 4. The control device 9 places the workpiece W into the second container C2 by releasing the grip of the workpiece W by the fingers 32 of the hand 3.

[0102] In this way, the robot 1 can make the hand 3 reach a complicated position by combining the advancing movement of the robot arm 2 and the raising and lowering movement of the wrist 4. The advancing movement of the robot arm 2 causes the hand 3 to enter a narrow space in the first direction X. After the hand 3 enters the narrow space in the first direction X, the movement of the robot arm 2 is restricted. In such a situation, the wrist 4 moves the hand 3 in the second direction Z. This allows the hand 3 to move in the second direction Z, which is different from the first direction X, within a narrow space without moving the robot arm 2. As a result, the hand 3 can reach a complicated position within a narrow space.

[0103] In addition, the wrist 4 moves the hand 3 more flexibly by pitching, rolling, and yawing. For example, the control device 9, specifically the motion controller 95, during the advancing operation changes the rotational posture of the hand 3 about the pitch axis P or the roll axis R to a posture different from that during the lifting / lowering operation, thereby extending the robot arm 2 in the first direction X. At this time, the control device 9 may change the rotational posture of the hand 3 about the pitch axis P or the roll axis R during the advancing operation depending on the size of the space through which the hand 3 and the wrist 4 pass during the advancing operation. In this example, the "space through which the hand 3 and the wrist 4 pass during the advancing operation" is the workspace H. In this example, the posture of the hand 3 during the lifting / lowering operation is such that the orientation of the fingers 32 around the pitch axis P faces away from the robot arm 2 in the second direction Z, and the orientation of the fingers 32 around the roll axis R faces vertically.

[0104] FIG. 20 is a side view of the hand 3 and the wrist 4 after the orientation of the hand 3 around the pitch axis P has been changed before the advancing operation. If the space through which the hand 3 and the wrist 4 pass during the advancing operation is narrow, highly accurate position control of the hand 3 and the wrist 4 may be required when the robot arm 2 advances the hand 3 and the wrist 4. In some cases, the hand 3 or the wrist 4 may interfere with another object, such as the shelf board s1 or the first container C1. The control device 9 adjusts the rotational orientation of the hand 3 around the pitch axis P or the roll axis R based on the size of the workspace H, specifically, the size of the workspace H in a cross section perpendicular to the first direction X. More specifically, the control device 9 adjusts the rotational orientation of the hand 3 based on the size of the workspace H in the direction in which the workspace H is smallest in the cross section of the workspace H perpendicular to the first direction X. In this example, the size of the workspace H in the vertical direction is smallest, so the control device 9 adjusts the rotational orientation of the hand 3 based on the vertical size of the workspace H.

[0105] As shown in FIG. 18 , the rotational posture of the hand 3 around the pitch axis P during lifting and lowering operations is typically a posture in which the fingers 32 face downward in the vertical direction. In this posture, the tips of the fingers 32 protrude vertically downward beyond the robot arm 2 and the wrist 4. Therefore, the overall size of the hand 3 and the like in the vertical direction is relatively large. In the example of FIG. 20 , the control device 9 adjusts the rotational posture of the hand 3 around the pitch axis P. Specifically, the control device 9 rotates the hand 3 around the pitch axis P via the wrist 4 so that the fingers 32 face horizontally, i.e., in the first direction X. This reduces the size of the hand 3 in the vertical direction. Note that if the workspace H is large enough, the rotational posture of the hand 3 may be a posture in which the fingers 32 face diagonally downward.

[0106] 20, the control device 9 also adjusts the position of the hand 3 in the vertical direction. Depending on the pitch movement of the wrist 4, the hand 3 or the wrist 4 may protrude in the vertical direction relative to the robot arm 2 (see FIG. 10). By changing the position of the hand 3 in the second direction Z to move away from the robot arm 2, the overall size of the robot arm 2, hand 3, and wrist 4 in the vertical direction can be reduced.

[0107] When the size of the workspace H is known, the control device 9 adjusts the rotational attitude of the hand 3 about the pitch axis P based on the known size of the workspace H. The control device 9 determines the rotational attitude of the hand 3 about the pitch axis P based on the size of the workspace H, and further determines the position of the hand 3 in the second direction Z.

[0108] Alternatively, the control device 9 may acquire the size of the workspace H using a camera or the like. For example, if the robot 1 has a camera 15 arranged in the hand 3, the control device 9 may cause the camera 15 to acquire an image of the workspace H from a position facing the shelf S, and determine the size of the workspace H from the acquired image by image recognition.

[0109] The control device 9 may adjust the rotational posture of the hand 3 around the roll axis R. FIG. 21 is a front view of the hand 3 and the wrist 4 when the rotational posture of the hand 3 during an advancing operation is changed by a roll operation. The rotational posture of the hand 3 around the roll axis R during an up-and-down operation is usually a posture in which the second direction Z faces vertically (see the two-dot chain line). In this posture, the tips of the fingers 32 protrude downward in the second direction Z below the robot arm 2 and the wrist 4. Therefore, the overall size of the hand 3 and the like in the vertical direction is relatively large. The control device 9 rotates the wrist 4 around the roll axis R. As the wrist 4 rotates around the roll axis R, the hand 3 also rotates around the roll axis R. In the example of FIG. 21 , the orientation of the fingers 32 changes to face horizontally. The workspace H is narrow in the vertical direction but wide in the horizontal direction. By orienting the fingers 32 horizontally, the direction in which the fingers 32 protrude from the hand 3 can be adjusted to a direction that provides ample space in the workspace H. As a result, the size of the hand 3 in the vertical direction is smaller than when the fingers 32 point vertically downward. If the working space H is large enough, the rotational posture of the hand 3 may be such that the fingers 32 point diagonally downward.

[0110] In this way, the control device 9 can adjust the overall size of the robot arm 2, hand 3, and wrist 4 to a size that can enter the workspace H by changing the rotational posture of the hand 3 around the pitch axis P or roll axis R to a posture different from that during the lifting and lowering operation.

[0111] The reference direction for adjusting the rotational posture of the hand 3 is not limited to the vertical direction. When the direction in which the workspace H is smallest among the directions orthogonal to the first direction X in a cross section of the workspace H that is orthogonal to the first direction X is not the vertical direction, the control device 9 adjusts the rotational posture of the hand 3 based on the size of the workspace H in the direction orthogonal to the first direction X that is smallest.

[0112] The control device 9, specifically the motion controller 95, may change the orientation of the second direction Z by changing the rotational posture of the wrist 4 around the roll axis R during the lifting operation. This adjusts the direction in which the wrist 4 lifts and lowers the hand 3 during the lifting operation.

[0113] 22 is a front view of the hand 3 and the wrist 4 in a state in which the link mechanism 6 has rotated about the roll axis R. For example, when the hand 3 enters the first container C1, the wrist 4 performs a roll motion, which changes the orientation of the second direction Z as shown in FIG. 22 . In other words, the second direction Z is tilted with respect to the vertical direction. From this state, the wrist 4 moves the hand 3 in the second direction Z away from the robot arm 2, causing the hand 3 to move linearly diagonally downward. This allows the arrival position of the hand 3 to be adjusted within a plane perpendicular to the roll axis R without moving the robot arm 2.

[0114] Furthermore, the change in the rotational posture of the wrist 4 around the roll axis R may be performed at any time before the hand 3 reaches the workpiece W: at the beginning of the lifting / lowering operation, during the lifting / lowering operation, or at the end of the lifting / lowering operation.

[0115] As a result of adjusting the reach position of the hand 3, the reach range of the hand 3 can be expanded. Figures 23, 24, and 25 are explanatory diagrams of a procedure for expanding the reach range of the hand 3. Figure 23 is a front view of the hand 3 and wrist 4 positioned above the first container C1. Figure 24 is a front view of the hand 3 and wrist 4 after a roll motion. Figure 25 is a front view of the hand 3 and wrist 4 after a straight motion. For example, if a workpiece W is positioned near the side wall of the first container C1, moving the hand 3 vertically from above toward the workpiece W may cause the hand 3 to interfere with the side wall of the first container C1. In such a case, as shown in Figure 23, the hand 3 is positioned away from the side wall of the first container C1. Then, as shown in Figure 24, the wrist 4 rolls to orient the second direction Z toward the workpiece W near the side wall. Next, as shown in Figure 25, the wrist 4 moves the hand 3 diagonally downward in a straight line by a straight motion. This allows the hand 3 to reach the workpiece W while avoiding interference with the side wall.

[0116] The control device 9, specifically the motion controller 95, may change the rotational posture of the hand 3 around the yaw axis Y during lifting and lowering operations. This adjusts the opening and closing direction of the fingers 32 of the hand 3. FIG. 26 is a side view of the hand 3 and the wrist 4 before yaw operation when picking multiple adjacent workpieces W. FIG. 27 is a side view of the hand 3 and the wrist 4 after yaw operation when picking multiple adjacent workpieces W. For example, a workpiece W may be positioned adjacent to another object, such as another workpiece W. In such a case, as shown in FIG. 26 , if the arrangement direction of the multiple workpieces W and the opening and closing direction of the fingers 32 coincide, the fingers 32 may interfere with the other workpieces W, making it impossible to properly grasp the target workpiece W. By performing a yaw operation of the wrist 4, the opening and closing direction of the fingers 32 can be made different from the arrangement direction of the multiple workpieces W, as shown in FIG. 27 . This allows the fingers 32 to properly grasp the target workpiece W without interfering with the other workpieces W. In this way, the wrist 4 performs a yaw movement, so that the opening and closing directions of the fingers 32 can be adjusted according to the situation around the workpiece W.

[0117] The change in the rotational posture of the hand 3 around the yaw axis Y may be performed at any time before the hand 3 reaches the workpiece W, either at the beginning of the lifting operation or during the lifting operation.

[0118] The control device 9, specifically the motion controller 95, may change the rotational posture of the hand 3 about the pitch axis P or the roll axis R during the retreating operation to a posture different from that during the lifting operation, thereby contracting the robot arm 2 in the first direction X. At this time, the control device 9 may change the rotational posture of the hand 3 about the pitch axis P or the roll axis R during the retreating operation in accordance with the size of the space through which the hand 3 and the wrist 4 pass during the retreating operation. In this example, the "space through which the hand 3 and the wrist 4 pass during the retreating operation" is the workspace H.

[0119] FIG. 28 is a side view of the hand 3 and wrist 4 when the hand 3 gripping the workpiece W is retracted in the second direction Z. FIG. 29 is a side view of the hand 3 and wrist 4 when the hand 3 gripping the workpiece W is rotated about the pitch axis P. If the space through which the hand 3 and wrist 4 pass during the retraction operation is narrow, high-precision position control of the hand 3 and wrist 4 may be required when the robot arm 2 retracts the hand 3 and wrist 4. In some cases, the hand 3 or wrist 4 may interfere with another object, such as a shelf board s1 or a first container C1. The control device 9 adjusts the rotational posture of the hand 3 about the pitch axis P or the roll axis R based on the size of the workspace H, specifically, the size of the workspace H in a cross section perpendicular to the first direction X. More specifically, the control device 9 adjusts the rotational posture of the hand 3 based on the size of the workspace H in a direction perpendicular to the first direction X in which the workspace H is smallest in the cross section of the workspace H perpendicular to the first direction X. In this example, the size of the workspace H in the vertical direction is smallest, so the control device 9 adjusts the rotational posture of the hand 3 based on the size of the workspace H in the vertical direction.

[0120] The rotational posture of the hand 3 around the pitch axis P during lifting operation is usually a posture in which the fingers 32 face downward in the vertical direction. In this posture, the workpiece W gripped by the fingers 32 is suspended downward. As shown in FIG. 28 , when the workpiece W is large, the overall vertical size of the hand 3 and the wrist 4 including the workpiece W increases. If the overall vertical size of the hand 3 and the like is large, the workpiece W may interfere with the first container C1 and the like when the robot arm 2 removes the hand 3 and the like from the workspace H. In the example of FIG. 29 , the control device 9 adjusts the rotational posture of the hand 3 around the pitch axis P. Specifically, the control device 9 rotates the hand 3 around the pitch axis P via the wrist 4 so that the fingers 32 face horizontally, i.e., in the first direction X. This reduces the vertical size of the hand 3 including the workpiece W. As a result, the robot arm 2 can more easily remove the hand 3 and the like from the workspace H. In addition, the control device 9 may also adjust the position of the hand 3 in the vertical direction. By changing the position of the hand 3 in the second direction Z so that the wrist 4 is away from the robot arm 2, the overall size of the robot arm 2, hand 3, and wrist 4 in the vertical direction can be reduced. Note that if the working space H is large enough, the rotational posture of the hand 3 may be such that the fingers 32 face diagonally downward.

[0121] The size of the workspace H may be known, as in the case of the advancing operation, or may be obtained from an image taken by a camera or the like.

[0122] The control device 9 may adjust the rotational posture of the hand 3 around the roll axis R. FIG. 30 is a front view of the hand 3 and the wrist 4 when the rotational posture of the hand 3 during a retreating operation is changed by a roll operation. The rotational posture of the hand 3 around the roll axis R during a lifting operation is usually a posture in which the second direction Z faces vertically. In this posture, the workpiece W is suspended downward from the hand 3. Therefore, the overall size of the hand 3 and the like in the vertical direction is relatively large. The control device 9 rotates the wrist 4 around the roll axis R. As the wrist 4 rotates around the roll axis R, the hand 3 also rotates around the roll axis R. In the example of FIG. 30 , the orientation of the fingers 32 changes to face horizontally. The workspace H is narrow in the vertical direction but is wide in the horizontal direction. By orienting the fingers 32 horizontally, the direction in which the workpiece W protrudes from the hand 3 can be adjusted to a direction that provides ample space in the workspace H. This reduces the overall vertical size of the hand 3 including the workpiece W compared to when the workpiece W is suspended downward. As a result, it becomes easier for the robot arm 2 to remove the hand 3 and the like from the workspace H. If the workspace H is large enough, the rotational posture of the hand 3 may be such that the fingers 32 face diagonally downward.

[0123] With regard to adjusting the rotational attitude of the hand 3 around the pitch axis P or the roll axis R during an advancing or retreating operation, when the hand 3 or the workpiece W comes into contact with another object, the control device 9 may change the rotational attitude of the hand 3 around the pitch axis P or the roll axis R depending on the size of the space through which the hand 3 and the wrist 4 pass during the advancing or retreating operation. The control device 9 predicts contact between the hand 3 or the workpiece W and the other object. Specifically, the control device 9 predicts contact between the workpiece W and the other object based on, for example, the size of the space through which the hand 3 and the wrist 4 pass (in this example, the size of the workspace H) and the size of the workpiece W.

[0124] In this way, the robot 1 can make the hand 3 reach complicated positions by combining the advancing movement of the robot arm 2 and the raising and lowering movement of the wrist 4. The advancing movement of the robot arm 2 does not significantly change the size of the robot arm 2 in any direction other than the first direction X. Therefore, the hand 3 can easily enter a narrow space in the first direction X while avoiding interference between the robot arm 2 and other objects. After the hand 3 enters the narrow space in the first direction X, the movement of the robot arm 2 may be restricted. In particular, if a portion of the robot arm 2 has entered the narrow space, the movement of the robot arm 2 is further restricted. In such a situation, the wrist 4 moves the hand 3 in the second direction Z. This allows the hand 3 to move in the second direction Z, which is different from the first direction X, within a narrow space without moving the robot arm 2. In this way, the hand 3 can reach complicated positions while avoiding interference between the robot arm 2 and other objects. As a result, the operating range of the hand 3 can be expanded in a narrow space where the movement of the robot arm 2 is restricted.

[0125] In addition, when operating the wrist 4, the moving parts are smaller and lighter than when operating the robot arm 2. Smaller moving parts reduce the possibility of interference with other parts. Lighter moving parts reduce the driving force required for movement and improve controllability. In other words, the wrist 4 has these advantages even when operating in places other than complicated locations.

[0126] Movement of the hand 3 in the second direction Z by the wrist 4 is achieved by a link mechanism 6 including a Chebyshev link mechanism 60. The linear movement amount achieved by the Chebyshev link mechanism 60 is relatively large. In other words, the stroke of the hand 3 in the second direction Z can be increased while preventing the link mechanism 6 from becoming too large. The Chebyshev link mechanism 60 operates when the driving link 61 is rotationally driven. Therefore, the Chebyshev link mechanism 60 is driven by a motor. For example, linear movement of the hand 3 can also be achieved by a combination of a linear guide and a cylinder, etc. However, a motor has higher controllability than a cylinder, etc. By employing the Chebyshev link mechanism 60, movement of the hand 3 in the second direction Z can be easily and accurately controlled.

[0127] During the advancement and retreat operations, by adjusting the rotational posture of the hand 3 around the pitch axis P or the roll axis R, it is possible to prevent the hand 3 or the workpiece W from interfering with other objects.

[0128] By adjusting the rotational posture of the hand 3 around the roll axis R during the lifting operation, the reachable position of the hand 3 can be adjusted without moving the robot arm 2.

[0129] By adjusting the rotational attitude of the hand 3 about the yaw axis Y during the lifting operation, the attitude of the hand 3 relative to the workpiece W can be adjusted. For example, the opening and closing directions of the fingers 32 relative to the workpiece W can be adjusted.

[0130] Such a robot arm 2 is attached to an elevator 12. The elevator 12 is attached to a carriage 11. The robot arm 2 is moved by the carriage 11 and the elevator 12. Therefore, the position of the hand 3 can also be adjusted by the carriage 11 and the elevator 12. Furthermore, the elevator 12 is disposed in a recess 11c of the carriage 11 and can lower the robot arm 2 below the upper surface 11b of the carriage 11, thereby expanding the operating range of the robot arm 2 by the elevator 12.

[0131] Other Embodiments As described above, the above-described embodiments have been described as examples of the technology disclosed in the present application. However, the technology of the present disclosure is not limited to these embodiments and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate. Furthermore, the components described in the above-described embodiments can be combined to create new embodiments. Furthermore, the components described in the accompanying drawings and detailed description may include not only components essential for solving the problem, but also components that are not essential for solving the problem in order to exemplify the technology. Therefore, the fact that these non-essential components are described in the accompanying drawings or detailed description should not be interpreted as immediately determining that these non-essential components are essential.

[0132] For example, the work performed by the robot 1 is not limited to transfer work. The robot 1 may also perform work such as assembling parts. In the case of transfer work, the robot 1 may pick up the workpiece W from the second container C2 and place it in the first container C1. In other words, the hand 3 may enter a narrow space during placement. The wrist 4 can flexibly move the hand 3 by performing the linear movement, pitch movement, roll movement, and yaw movement as described above when placing the workpiece W. The wrist 4 can also perform the linear movement, pitch movement, roll movement, and yaw movement as described above when picking the workpiece W from the second container C2. The workpiece W before and after transfer do not have to be placed in a container. For example, the workpiece W before transfer may be placed on a tray, pallet, or conveyor. The workpiece W after transfer may be placed on a tray, pallet, or conveyor. The narrow space is not limited to the workspace H. The robot 1 can have the hand 3 enter various spaces that the robot arm 2 can enter.

[0133] The processing by the hand 3 is not limited to holding a workpiece. For example, the processing by the hand 3 may be machining, welding, painting, etc. Holding a workpiece by the hand 3 is not limited to gripping, but may be by suction or the like.

[0134] The pitch, roll, and yaw movements by the wrist 4 are not essential. The wrist 4 only needs to move the hand 3 in at least a direction intersecting the extension / retraction direction of the robot arm 2, i.e., in the second direction Z. For example, the wrist 4 may combine at least one of the pitch, roll, and yaw movements with movement in the second direction Z.

[0135] The mechanism for moving the hand 3 in the wrist 4 in the second direction Z is not limited to the link mechanism 6. The wrist 4 may move the hand 3 in the second direction Z by a pantograph mechanism. Alternatively, the wrist 4 may move the hand 3 in the second direction Z by a belt mechanism, a feed screw mechanism, or a linear actuator including a rack and pinion. Such a mechanism, for example, connects the first base 41 and the second base 42 to each other and enables the second base 42 to move in the second direction Z relative to the first base 41.

[0136] The link mechanism 6 includes two link mechanisms, a first link mechanism 6A and a second link mechanism 6B. However, the link mechanism 6 may include only one of the first link mechanism 6A and the second link mechanism 6B. Alternatively, the link mechanism 6 may include three or more link mechanisms.

[0137] Regarding the roll operation, the rotating body 44 is rotatably connected to the base main body 43 of the first base 41 around the roll axis R. This causes the link mechanism 6, the second base 42, and the hand 3 to rotate around the roll axis R. However, the configuration related to the roll operation is not limited to this. The second base 42 may be configured with a divided body that can rotate around the roll axis. In this case, the link mechanism 6 does not rotate around the roll axis R, but the hand 3 rotates around the roll axis R.

[0138] Regarding the pitch movement, the second base 42 is connected to the link mechanism 6 so as to be rotatable about the pitch axis P. This causes the hand 3 to rotate about the pitch axis P. However, the configuration related to the pitch movement is not limited to this. The first base 41 may be configured as a divided body that is rotatable about the pitch axis. In this case, the link mechanism 6, the second base 42, and the hand 3 rotate about the pitch axis.

[0139] Regarding the yaw movement, the rotor 46 is connected to the base main body 45 of the second base 42 so as to be rotatable about the yaw axis Y. This causes the hand 3 to rotate about the yaw axis Y. However, the configuration related to the yaw movement is not limited to this. The first base 41 may be configured with divided bodies that are rotatable about the yaw axis. In this case, the link mechanism 6, the second base 42, and the hand 3 rotate about the yaw axis.

[0140] The camera 15 may be disposed on the shelf s1 or the like instead of on the hand 3. When the control device 9 detects the workpiece W or the space for entry from an image, the control device 9 may obtain the image not from the camera 15 but from an external source.

[0141] The determiner 97 may determine interference between the hand 3 or the workpiece W and another object based on the detection results of a force sensor included in the robot 1. In this case, the determiner 97 determines contact based on the detection results of the force sensor. For example, the force sensor may be disposed on the robot arm 2, the hand 3, or the wrist 4. When the hand 3 or the workpiece W comes into contact with another object, the force sensor may detect a force or torque corresponding to the contact. When the control device 9 detects contact between the hand 3 or the workpiece W and another object based on the detection results from the force sensor, it adjusts the rotational posture of the hand 3 around the pitch axis P or the roll axis R. Note that the sensor that detects contact is not limited to a force sensor. The sensor that detects contact may be an acceleration sensor disposed on the robot arm 2, the hand 3, or the wrist 4, or a current sensor of each motor of the robot arm 2, the hand 3, or the wrist 4. In the case of an acceleration sensor, the acceleration sensor detects the acceleration at the time of contact, allowing the determiner 97 to determine contact between the hand 3 or the workpiece W and another object. In the case of a current sensor, the current sensor detects an increase in the motor current, and the determiner 97 can determine whether the hand 3 or the workpiece W has come into contact with another object.

[0142] The robot control device 10 may not be separate from the control device 9, but may be configured integrally with the control device 9. In other words, the control device 9 may also have the functions of the robot control device 10.

[0143] The functions performed by the components described herein may be implemented in circuitry or processing circuitry, including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), a Central Processing Unit (CPU), conventional circuits, and / or combinations thereof, programmed to perform the described functions. A processor includes transistors and other circuits and is considered a circuit or processing circuit. A processor may also be a programmable processor that executes a program stored in a memory.

[0144] In this specification, a circuit, unit, or means is hardware that is programmed to realize or performs the described functions, which may be any hardware disclosed herein or any hardware known to be programmed to realize or perform the described functions.

[0145] If the hardware is a processor considered to be a type of circuitry, the circuit, means, or unit is a combination of hardware and software used to configure the hardware and / or processor.

[0146] The technology of the present disclosure can be summarized as follows.

[0147] [1] A robot system 100 includes a robot 1 and a control device 9 that controls the robot 1. The robot 1 has a robot arm 2 that extends and retracts in a predetermined first direction X, a wrist 4 connected to the robot arm 2, and a hand 3 connected to the wrist 4. The wrist 4 moves the hand 3 in a second direction Z that intersects with the first direction X. The control device 9 causes the robot 1 to perform an advancing operation in which the wrist 4 and the hand 3 move in the first direction X by extending the robot arm 2 in the first direction X, and an ascending / descending operation in which the wrist 4 moves the hand 3 in the second direction Z after the advancing operation.

[0148] According to this configuration, movement of the hand 3 in the first direction X is achieved by extending the robot arm 2, and movement of the hand 3 in the second direction Z is achieved by the wrist 4. When the robot arm 2 is extended, the size of the robot arm 2 does not change significantly in any direction other than the first direction X. Therefore, in the advancing operation, the hand 3 and the wrist 4 can enter a narrow space while avoiding interference between the robot arm 2 and other objects. In the lifting operation, the hand 3 can be moved in the second direction Z by the wrist 4 without moving the robot arm 2. Therefore, in the lifting operation, the hand 3 can be moved in the second direction Z, which is different from the first direction X, while avoiding interference between the robot arm 2 and other objects. In this way, by combining the advancing operation and the lifting operation, the operating range of the hand 3 can be expanded without large movements of the robot arm 2. As a result, the operating range of the hand 3 in a narrow space can be expanded.

[0149] [2] In the robot system 100 described in [1], the wrist 4 supports the hand 3 rotatably around at least one of a pitch axis P extending in a direction intersecting both the first direction X and the second direction Z and a roll axis R extending in the first direction X, and the control device 9, during the advancing operation, changes the rotational posture of the hand 3 around the pitch axis P or the roll axis R to a posture different from that during the lifting operation, thereby extending the robot arm 2 in the first direction X.

[0150] This configuration prevents the hand 3 from interfering with other objects during the advancing operation. More specifically, as described above, the hand 3 having the fingers 32 may have the fingers 32 extending in the second direction Z during the lifting operation. Various types of hand 3 may be employed, but regardless of the type, the hand 3 may be protruding in a direction intersecting the first direction X. In such a case, by rotating the hand 3 around the pitch axis P, the overall size of the hand 3 in a cross section perpendicular to the first direction X can be reduced. This allows the hand 3 to easily advance in the first direction X while avoiding interference between the hand 3 and other objects. Alternatively, by rotating the hand 3 around the roll axis R, the protruding direction of the hand 3 can be adjusted to a direction that provides clearance between the hand 3 and surrounding objects. This allows the hand 3 to easily advance in the first direction X while avoiding interference between the hand 3 and other objects.

[0151] [3] In the robot system 100 described in [1] or [2], the control device 9 changes the rotational posture of the hand 3 around the pitch axis P or the roll axis R during the advancing operation in accordance with the size of the space through which the wrist 4 and the hand 3 pass during the advancing operation.

[0152] With this configuration, the hand 3 can be rotated around the pitch axis P or the roll axis R depending on the size of the space through which the hand 3 and wrist 4 pass, for example, the size of the working space H. As a result, interference between the hand 3 and other objects during the advancing operation can be easily avoided.

[0153] [4] In the robot system 100 described in any one of [1] to [3], the wrist 4 supports the hand 3 rotatably around at least one of a pitch axis P extending in a direction intersecting both the first direction X and the second direction Z and a roll axis R extending in the first direction X, and the control device 9 causes the robot 1 to further execute a holding operation in which the hand 3 holds a workpiece W after the lifting / lowering operation, and a retraction operation in which the robot arm 2 is retracted in the first direction X after the holding operation, thereby moving the wrist 4 and the hand 3 in the first direction X, and in the retraction operation, the rotational posture of the hand 3 about the pitch axis P or the roll axis R is changed to a posture different from that during the lifting / lowering operation, and the robot arm 2 is retracted in the first direction X.

[0154] According to this configuration, the hand 3 holds the workpiece W by the holding operation. Depending on the holding method, the workpiece W may protrude from the hand 3. In other words, the overall size of the hand 3 including the workpiece W may increase. Therefore, by rotating the hand 3 around the pitch axis P during the retraction operation, the overall size of the hand 3 including the workpiece W in a cross section perpendicular to the first direction X can be reduced. This allows the hand 3 to easily retract in the first direction X while avoiding interference between the workpiece W and other objects. Alternatively, by rotating the hand 3 around the roll axis R, the protruding direction of the workpiece W can be adjusted to a direction that provides clearance between the workpiece W and surrounding objects. This allows the hand 3 to easily advance in the first direction X while avoiding interference between the workpiece W and other objects.

[0155] [5] In the robot system 100 described in any one of [1] to [4], the control device 9 changes the rotational posture of the hand 3 around the pitch axis P or the roll axis R during the retreating operation in accordance with the size of the space through which the wrist 4 and the hand 3 pass during the retreating operation.

[0156] According to this configuration, the hand 3 can be rotated around the pitch axis P or the roll axis R depending on the size of the space through which the hand 3 and wrist 4 pass, for example, the size of the working space H. As a result, interference between the workpiece W and other objects during the retreating operation can be avoided with greater precision.

[0157] [6] In the robot system 100 described in any one of [1] to [5], when the workpiece W held by the hand 3 comes into contact with another object during the retreating operation, the control device 9 changes the rotational posture of the hand 3 around the pitch axis P or the roll axis R according to the size of the space through which the wrist 4 and the hand 3 pass during the retreating operation.

[0158] According to this configuration, when the workpiece W comes into contact with another object, the hand 3 is rotated around the pitch axis P or the roll axis R. Contact of the workpiece W with another object may be predicted in advance, or its actual occurrence may be determined. When the workpiece W does not come into contact with another object, the hand 3 does not need to rotate around the pitch axis P or the roll axis R, which simplifies the operation.

[0159] [7] In the robot system 100 described in any one of [1] to [6], the wrist 4 is rotatable around a roll axis R extending in the first direction X, and the control device 9 changes the orientation of the second direction Z by changing the rotational posture of the wrist 4 around the roll axis R during the lifting and lowering operation.

[0160] According to this configuration, the wrist 4 that moves the hand 3 in the second direction Z rotates around the roll axis R, so that the second direction Z rotates around the roll axis R. This changes the orientation of the second direction Z, i.e., the orientation of the direction of movement of the hand 3 by the wrist 4. As a result, the reachable position of the hand 3 can be adjusted without moving the robot arm 2. In addition, even for workpieces W that are difficult to access from a certain direction, changing the orientation of the movement direction of the hand 3 makes it easier for the hand 3 to access the workpiece W.

[0161] [8] In the robot system 100 described in any one of [1] to [7], the wrist 4 supports the hand 3 rotatably around a yaw axis Y extending in a direction intersecting the first direction X, and the control device 9 changes the rotational posture of the hand 3 around the yaw axis Y during the lifting and lowering operation.

[0162] According to this configuration, the attitude of the hand 3 with respect to the workpiece W can be adjusted by rotating the hand 3 around the yaw axis Y. For example, if the hand 3 has multiple fingers 32 that open and close, the opening and closing directions of the fingers 32 with respect to the workpiece W can be adjusted.

[0163] [9] In the robot system 100 described in any one of [1] to [8], the robot 1 further includes a carriage 11 including a box-shaped main body 11a, and an elevator 12 arranged on the carriage 11 and supporting the robot arm 2 so that the robot arm 2 can be raised and lowered in a predetermined third direction, the carriage 11 having a recess 11c recessed downward from an upper surface 11b of the carriage 11, and the elevator 12 arranged in the recess 11c and lowering the robot arm 2 to a position below the upper surface 11b.

[0164] According to this configuration, the robot arm 2 moves by movement of the carriage 11 and elevation by the elevator 12. The elevator 12 is disposed in the recess 11c of the carriage 11, and can lower the robot arm 2 to below the upper surface 11b of the carriage 11. As a result, the position of the robot arm 2 can be adjusted over a wide range in the third direction.

Claims

1. A robot system comprising: a robot; and a control device that controls the robot, wherein the robot has a robot arm that extends and retracts in a predetermined first direction, a wrist connected to the robot arm, and a hand connected to the wrist, wherein the wrist moves the hand in a second direction that intersects the first direction, and the control device causes the robot to perform an advancing operation to move the wrist and the hand in the first direction by extending the robot arm in the first direction, and a lifting operation to move the hand in the second direction by the wrist after the advancing operation.

2. A robot system as described in claim 1, wherein the wrist supports the hand rotatably around at least one of a pitch axis extending in a direction intersecting both the first direction and the second direction and a roll axis extending in the first direction, and the control device changes the rotational posture of the hand around the pitch axis or the roll axis to a posture different from that during the lifting and lowering operation, thereby extending the robot arm in the first direction.

3. A robot system as described in claim 2, wherein the control device changes the rotational posture of the hand around the pitch axis or the roll axis during the advancing operation depending on the size of the space through which the wrist and hand pass during the advancing operation.

4. A robot system as described in claim 1, wherein the wrist supports the hand rotatably around at least one of a pitch axis extending in a direction intersecting both the first direction and the second direction and a roll axis extending in the first direction, and the control device further causes the robot to perform a holding operation to cause the hand to hold a workpiece after the lifting / lowering operation, and a retracting operation to move the wrist and the hand in the first direction by retracting the robot arm in the first direction after the holding operation, and wherein during the retracting operation, the rotational posture of the hand around the pitch axis or the roll axis is changed to a posture different from that during the lifting / lowering operation, and the robot arm is retracted in the first direction.

5. A robot system as described in claim 4, wherein the control device changes the rotational posture of the hand around the pitch axis or the roll axis during the retreating motion depending on the size of the space through which the wrist and hand pass during the retreating motion.

6. A robot system as described in claim 4, wherein the control device changes the rotational posture of the hand around the pitch axis or the roll axis depending on the size of the space through which the wrist and hand pass during the retreating motion when the workpiece held by the hand comes into contact with another object during the retreating motion.

7. A robot system as described in claim 1, wherein the wrist is rotatable about a roll axis extending in the first direction, and the control device changes the orientation in the second direction by changing the rotational posture of the wrist about the roll axis during the lifting and lowering operation.

8. A robot system as described in claim 1, wherein the wrist supports the hand rotatably about a yaw axis extending in a direction intersecting the first direction, and the control device changes the rotational posture of the hand about the yaw axis during the lifting and lowering operation.

9. A robot system as described in claim 1, wherein the robot further comprises a carriage including a box-shaped main body, and an elevator arranged on the carriage and supporting the robot arm so that the robot arm can be raised and lowered in a predetermined third direction, the carriage having a recess recessed downward from an upper surface of the carriage, and the elevator arranged in the recess and lowering the robot arm to a position below the upper surface.

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