Robot system

Abstract

The invention provides a robot system. The robot system (1000) comprises a hand (2), a robot arm (10) and a control device (100), the robot arm (10) is connected with the hand (2), and the control device (100) controls the hand (2) and the robot arm (10). The hand (2) is provided with a hand body (3) and a plurality of fingers (4) which are arranged on the hand body (3) and perform opening and closing actions. Each of the plurality of fingers (4) has an endless belt (5) that is wound around at least the tip of the finger (4), is rotationally driven, and comes into contact with the workpiece (W). The control device (100) causes the hand (2) and the robot arm (10) to execute a search operation for changing the relative positions of the tips of the plurality of fingers (4) and the workpiece (W) in a state in which the plurality of fingers (4) are opened at predetermined intervals and the endless belt (5) is rotated when the tips of the plurality of fingers (4) are brought into contact with the workpiece (W) and the workpiece (W) is pulled between the plurality of fingers (4) by the endless belt (5).

Description

Technical Field

[0001] This invention relates to robot systems. Background Technology

[0002] To date, robotic systems that allow a workpiece to be held by the fingers of a hand by pulling it between the fingers are well known. For example, the hand of the robotic system described in Patent Document 1 includes fingers with a drive belt that is driven by rotation. This robotic system moves the hand to a position where the workpiece is held between two fingers, and the drive belt pulls the workpiece between the two fingers.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2014-24143

[0004] When a workpiece is pulled between multiple fingers by a conveyor belt, the workpiece is pulled in by properly embedding it between the tips of the fingers. If the positional accuracy of the tips of the fingers relative to the workpiece is low, there is a risk that the workpiece cannot be pulled in between the fingers. Proper workpiece pulling can be achieved by improving the positional accuracy of the fingers. However, improving the positional accuracy of the fingers increases the difficulty of control and reduces the speed of the control action. Summary of the Invention

[0005] In view of the above, the object of the present invention is to make it easier to control the pulling in of the workpiece.

[0006] The robot system of the present invention includes a hand, a robot arm, and a control device. The robot arm is connected to the hand, and the control device controls the hand and the robot arm. The hand has a hand body and multiple fingers disposed on the hand body and capable of opening and closing. Each of the multiple fingers has an endless band wrapped around the tip of at least one finger and driven by rotation to contact a workpiece. When the tip of the multiple fingers contacts the workpiece and the endless band pulls the workpiece between the multiple fingers, the control device, while the multiple fingers are opened at a predetermined interval and the endless band is rotated, causes the hand and the robot arm to perform a search action that changes the relative position of the tip of the multiple fingers and the workpiece.

[0007] (Invention effect)

[0008] The robot system makes it easy to control the pulling of workpieces. Attached Figure Description

[0009] Figure 1 This is a schematic diagram showing the structure of the robot system.

[0010] Figure 2 This is the front view of the hand.

[0011] Figure 3 This is a bottom view of the hand.

[0012] Figure 4 yes Figure 3 A cross-sectional view of the hand along line IV-IV.

[0013] Figure 5 yes Figure 3 A cross-sectional view of the hand with VV lines.

[0014] Figure 6 yes Figure 4 A cross-sectional view of the hand along line VI-VI.

[0015] Figure 7 It is a 3D diagram of a finger.

[0016] Figure 8 It is a side view of a finger.

[0017] Figure 9 yes Figure 8 A cross-sectional view of the finger along the IX-IX line.

[0018] Figure 10 This is the front view of the finger itself and its support.

[0019] Figure 11 yes Figure 8 A cross-sectional view of the fingers along the XI-XI line.

[0020] Figure 12 From and Figure 7 3D images of fingers from different angles.

[0021] Figure 13 This is the front view of the finger.

[0022] Figure 14 This is a front view of a finger in a state where the finger body has shifted backward in the second direction.

[0023] Figure 15 This is a diagram showing the general hardware structure of the control device.

[0024] Figure 16 This is a block diagram showing the structure of the processor's control system.

[0025] Figure 17 This is a flowchart of the pick-and-place process.

[0026] Figure 18 This is a diagram illustrating an example of a hand's search action.

[0027] Figure 19 This is a schematic diagram showing when the workpiece is successfully pulled in.

[0028] Figure 20 This is a diagram illustrating the state of the fingers when the workpiece is pulled in.

[0029] Figure 21 These are illustrations of other examples used to illustrate the search action of the hand.

[0030] Figure 22 These are illustrations of other examples used to illustrate the search action of the hand. Detailed Implementation

[0031] Hereinafter, the illustrated embodiments will be described in detail with reference to the accompanying drawings. Figure 1 This is a schematic diagram showing the structure of the robot system 1000. In this invention, parallel, orthogonal, identical, consistent, simultaneous, or central not only includes strictly speaking parallel, orthogonal, identical, consistent, simultaneous, or central, but also substantially parallel, orthogonal, identical, consistent, simultaneous, or central.

[0032] Robot system 1000 includes a hand 2, a robotic arm 10, and a control device 100. The robotic arm 10 is connected to the hand 2, and the control device 100 controls the hand 2 and the robotic arm 10. The hand 2 and the robotic arm 10 are contained within a robot 1. That is, robot system 1000 includes robot 1, which includes the hand 2 and the robotic arm 10. Robot system 1000 uses the hand 2 to pick up a workpiece W. In this example, robot system 1000 picks up one workpiece W from a plurality of workpieces W randomly stacked in container 19. However, robot system 1000 can also pick up a single, individually configured workpiece W.

[0033] Robot 1 is, for example, an industrial robot. Robot 1 uses a robot arm 10 to move a hand 2. Hand 2 is one of the so-called end effectors. Hand 2 holds a workpiece W.

[0034] The robotic arm 10 is configured for three-dimensional motion. Specifically, the robotic arm 10 is configured to perform translational movements involving at least three degrees of freedom. In this example, the robotic arm 10 is a vertical multi-joint robotic arm. The robotic arm 10 is supported by a base 13. The robotic arm 10 has multiple links, multiple joints, and servo motors, wherein the multiple joints connect to the multiple links, and the servo motors drive the rotation of the multiple joints.

[0035] In detail, the robotic arm 10 has a first link 11a, a second link 11b, a third link 11c, a fourth link 11d, and a fifth link 11e. The first link 11a is connected to the base 13, the second link 11b is connected to the first link 11a, the third link 11c is connected to the second link 11b, the fourth link 11d is connected to the third link 11c, and the fifth link 11e is connected to the fourth link 11d.

[0036] Specifically, the base 13 and the first link 11a are connected to each other via a first joint 12a, which is rotatable about an axis extending in a vertical direction. The first link 11a and the second link 11b are connected to each other via a second joint 12b, which is rotatable about an axis extending in a horizontal direction. The second link 11b and the third link 11c are connected to each other via a third joint 12c, which is rotatable about an axis extending in a horizontal direction. The third link 11c and the fourth link 11d are connected to each other via a fourth joint 12d, which is rotatable about the axis of the fourth link 11d (i.e., the direction in which the fourth link 11d extends). The fourth link 11d and the fifth link 11e are connected to each other via a fifth joint 12e, which is rotatable about an axis orthogonal to the axis of the fourth link 11d.

[0037] The robot arm 10 has servo motors that drive the rotation of each joint. Each servo motor has an encoder.

[0038] The robotic arm 10 configured in this way is configured to perform translational movements in each of the three orthogonal axes and rotational movements around each of the three orthogonal axes.

[0039] The robot system 1000 may also include a camera 15 for acquiring images of workpieces W. The camera 15 is fixedly positioned above the container 19. The camera 15 captures images of the interior of the container 19 from above. The camera 15 acquires images containing multiple workpieces W within the container 19.

[0040] Here, the image can be a two-dimensional image or a three-dimensional image. A three-dimensional image can be point cloud data, an RGB-D image, an RGB image, a depth image, or a voxel image, etc. In other words, the camera 15 can be a three-dimensional camera, namely, an RGB-D camera that outputs RGB-D images, a stereo camera that acquires RGB images, or a three-dimensional vision sensor that acquires point cloud data, etc.

[0041] Figure 2 This is the main view of hand 2. Figure 3 This is the bottom view of hand 2. Figure 4 yes Figure 3 A cross-sectional view of the hand along line IV-IV. Figure 5 yes Figure 3 A cross-sectional view of the VV line of the hand 2. Figure 6 yes Figure 4 A sectional view of the hand along line VI-VI. It should be noted that... Figure 2 In the middle, the front side wall of the hand body 3 is omitted.

[0042] Hand 2 has a hand body 3 and multiple fingers 4 disposed on the hand body 3 and capable of opening and closing actions. In this example, hand 2 includes two fingers 4. A predetermined reference axis P is provided on hand 2. Figure 2 As shown, fingers 4 extend from the hand body 3 towards the reference axis P. Multiple fingers 4 open and close in an opening / closing direction A orthogonal to the reference axis P. The reference axis P is located at the center of the multiple fingers 4 in the opening / closing direction A. That is, in the fully closed state, the multiple fingers 4 are in contact with each other on the reference axis P.

[0043] Each of the plurality of fingers 4 has an endless band 5 that contacts the workpiece W. The endless band 5 is wound around at least the front end of the finger 4 and is driven by rotation. Each finger 4 has an inner surface 4a that faces the other fingers 4. The inner surface 4a is formed by the endless band 5. The portion of the endless band 5 that corresponds to the inner surface 4a extends along the length direction of the finger 4. A portion of the endless band 5 of one finger 4 and a portion of the endless band 5 of another finger 4 face each other in the opening-closing direction A. In the opening-closing direction A, the side that opens the plurality of fingers 4 is called the "open side", and the side that closes the plurality of fingers 4 is called the "closed side".

[0044] like Figure 5 As shown, hand 2 has an opening / closing actuator 7 that causes multiple fingers 4 to open and close in the opening / closing direction A. The multiple fingers 4 move towards or away from each other in the opening / closing direction A via the opening / closing actuator 7. In this way, the multiple fingers 4 grasp the workpiece W, or release the grasp of the workpiece W. In this example, the opening / closing actuator 7 actuates two fingers 4. That is, hand 2 has an opening / closing actuator 7 shared by two fingers 4.

[0045] like Figure 6 As shown, the hand 2 has a rotary actuator 8 that rotates the endless belt 5. The endless belt 5 is driven to rotate by the rotary actuator 8. At this time, the portion of the endless belt 5 corresponding to the inner surface 4a moves along the length direction of the fingers 4. The hand 2 pulls the workpiece W between the multiple fingers 4 or sends the workpiece W out between the multiple fingers 4 by rotating the endless belt 5 of each finger 4.

[0046] Hand 2 holds workpiece W in multiple ways. In one way, hand 2 brings the tips of multiple fingers 4 into contact with workpiece W, and an endless strap 5 pulls workpiece W between the fingers 4. In other ways, hand 2 holds workpiece W by opening and closing the multiple fingers 4 in the opening / closing direction A. Figure 3 As shown, the hand 2 also has a sensor 210, which detects the pulling of the workpiece W between the plurality of fingers 4.

[0047] =Finger flexibility=

[0048] like Figure 2As shown, finger 4 can elastically displace in a first direction X, which involves the opening and closing of multiple fingers 4. Furthermore, finger 4 can elastically displace in a second direction Y, which involves advancing or retreating relative to the hand body 3. The first direction X is approximately the same as the opening and closing direction A. In this example, each of the multiple fingers 4 independently and elastically displaces in the first direction X. The second direction Y is the same as the direction of the reference axis P; in other words, it is the same as the direction in which finger 4 extends from the body 3. The second direction Y is a direction that intersects the opening and closing direction A; more specifically, it is orthogonal to the opening and closing direction A. In the second direction Y, the side where finger 4 enters or exits from the body 3 is simply referred to as the "entry / exit side," and the side where finger 4 retreats towards the hand body 3 is simply referred to as the "retreat side." In this example, each of the multiple fingers 4 independently and elastically displaces in the second direction Y.

[0049] Figure 7 It's a 3D image of finger 4. In Figure 7 The terminology is omitted here. Finger 4 has a base 41 and a finger body 42. The base 41 is supported by the hand body 3, and the finger body 42 is elastically displaceable in a first direction X and elastically displaceable in a second direction Y, and is supported relative to the base 41. The base 41 is movable in the opening / closing direction A and supported by the hand body 3 (see reference). Figure 2 , Figure 5 Specifically, the base 41 is supported by the hand body 3 via the feed screw 72 of the opening / closing actuator 7, which will be described later. The finger body 42 is supported by the base 41 and can rock about a predetermined rocking axis B. The rocking axis B is orthogonal to both the opening / closing direction A and the second direction Y. The finger body 42 is displaced in the first direction X by rocking about the rocking axis B. That is, the first direction X is a circumferential direction centered on the rocking axis B.

[0050] like Figure 7 As shown, the finger body 42 is elongated. One end of the finger body 42 along its length is called the first end 42a, and the other end of the finger body 42 along its length is called the second end 42b. The first end 42a is the end that leaves the hand body 3 and is the front end of the finger body 42.

[0051] More specifically, the finger 4 has a support 43 that supports the finger body 42 relative to the base 41. That is, the finger body 42 is supported by the base 41 via the support 43. Figure 8 This is a side view of finger 4. Figure 9 yes Figure 8 A cross-sectional view of finger 4 along the IX-IX line. Figure 10 This is a front view of the finger body 42 and the support 43. It should be noted that... Figure 8 The 5th character has been omitted.

[0052] like Figure 9As shown, the support 43 rotatably supports the support shaft 44 via a bearing about the axis of the support shaft 44. The axis of the support shaft 44 is the rocking shaft B. The support shaft 44 rotatably supports the finger body 42 about the rocking shaft B via a bearing. That is, the support 43 rotatably supports the finger body 42 about the rocking shaft B via the support shaft 44. The support shaft 44 supports the second end 42b of the finger body 42.

[0053] like Figure 10 As shown, the support 43 supports the finger body 42 in a suspended manner. The length direction of the finger body 42 suspended by the support 43 is aligned with the second direction Y. From this state, the finger body 42 swings about the swing axis B in the first direction X. As a result, the finger body 42 moves closer to or away from other finger bodies 42, that is, it shifts in the direction in which the finger 4 opens and closes.

[0054] like Figure 10 As shown, the support 43 has a first stop 43a and a second stop 43b to restrict the shaking of the finger body 42. The first stop 43a is disposed on the open side of the finger 4 relative to the finger body 42. The first stop 43a is an elongated plate shape. Figure 10 As shown by the two dashed lines, the finger body 42 contacts the first stop 43a when it moves towards the open side of the finger 4, thereby limiting the movement of the finger body 42 towards the open side of the finger 4.

[0055] The second stop 43b is disposed on the closed side of the finger 4 relative to the finger body 42. The second stop 43b is a pivot extending parallel to the rocking shaft B (see reference). Figure 7 The displacement of the finger body 42 towards the closed side of the finger 4 is limited by the finger body 42 contacting the second stop 43b when the finger body 42 moves toward the closed side of the finger 4.

[0056] The first stop 43a and the second stop 43b limit the amplitude of the shaking of the finger body 42. Since the finger body 42 shakes only with a small amplitude from the state of extending in the second direction Y, the first direction X is approximately consistent with the opening and closing direction A.

[0057] Figure 11 yes Figure 8 A cross-sectional view of finger 4 along line XI-XI. Hand 2 also includes a torsion spring 45, which exerts force on finger body 42 in a first direction X toward the closed side of finger 4. The axis of torsion spring 45 is located off-center from rocking shaft B. Torsion spring 45 has a coil 45a, a first arm 45b, and a second arm 45c.

[0058] A torsion spring 45 is disposed on the finger body 42. The finger body 42 has a support shaft 42c that supports the coil 45a of the torsion spring 45 and a contact shaft 42d that contacts the first arm 45b of the torsion spring 45. The support shaft 42c and the contact shaft 42d are disposed near the second stop 43b and extend parallel to the rocking shaft B. The support shaft 42c is inserted into the coil 45a of the torsion spring 45. The second arm 45c of the torsion spring 45 contacts the second stop 43b. The torsion spring 45 exerts force on the contact shaft 42d and the second stop 43b in directions opposite to each other. More specifically, the support shaft 42c, the contact shaft 42d, and the second stop 43b are disposed on the side opposite to the first end 42a of the finger body 42, with reference to the rocking shaft B. The contact shaft 42d is located on the closed side of the finger 4 in a circumferential direction centered on the rocking shaft B, compared to the second stop 43b. That is, in the circumferential direction centered on the rocking shaft B, the direction in which the contact shaft 42d moves away from the second stop 43b is the direction in which the finger body 42 rocks toward the closed side of the finger 4. In this way, through the force applied by the torsion spring 45, a torque acting on the finger body 42 in the direction of the closed side of the finger 4 centered on the rocking shaft B is applied.

[0059] When no external force is applied to the finger body 42 (i.e., the normal state), the finger body 42 is pulled away from the first stop 43a and contacts the second stop 43b due to the force applied by the torsion spring 45. In other words, the finger body 42 in the normal state can elastically displace towards the open side of the finger 4.

[0060] Figure 12 From and Figure 7 A 3D view of finger 4 from different angles. Figure 12 The terminator 5 is omitted. The support 43 is displaceable in the second direction Y and connected to the base 41. The support 43 is connected to the base 41 via a pair of linear guides 46. The linear guides 46 guide the support 43 in the second direction Y.

[0061] like Figure 9 As shown, each linear guide 46 has a first guide rail 46a, a second guide rail 46b, and a plurality of balls or rollers disposed between the first guide rail 46a and the second guide rail 46b. The first guide rail 46a and the second guide rail 46b are movable relative to each other in a second direction Y. The first guide rail 46a is mounted on a base 41, and the second guide rail 46b is mounted on a support 43. Specifically, the second guide rail 46b is mounted on a first stop 43a.

[0062] As the support 43 moves relative to the base 41 in the second direction Y via the linear guide 46, the finger body 42 supported by the support 43 also moves relative to the base 41 in the second direction Y.

[0063] Figure 13This is the front view of finger 4. (Example) Figure 13 As shown, the support 43 is forceped by the spring 47 towards the inlet / outlet side in the second direction Y. For example, the spring 47 is a coil spring. The support 43 has a pin 43c that protrudes towards the retracted side in the second direction Y. On the other hand, the base 41 has a pin 41a protruding towards the inlet / outlet side in the second direction Y at a position corresponding to the pin 43c. One end of the spring 47 is mounted on the pin 41a, and the other end of the spring 47 is mounted on the pin 43c. At this time, the spring 47 is compressed. The elastic force of the spring 47 is towards the second direction Y. The spring 47 exerts a force on the pin 41a and the pin 43c in a direction that causes them to move away from each other. That is, the spring 47 exerts a force on the support 43 relative to the base 41 towards the inlet / outlet side in the second direction Y.

[0064] As a result, the finger body 42 is forced by the spring 47 relative to the base 41 in the second direction Y towards the inward or outward side. The finger body 42 is able to overcome the elastic force of the spring 47 and displace in the second direction Y towards the backward side. Figure 14 This is a front view of finger 4, showing the finger body 42 displaced backward in the second direction Y. Figure 14 In the diagram, spring 47 is partially cut open. The finger body 42 can be displaced towards the rearward side in the second direction Y until pins 41a and 43c contact. That is, pins 41a and 43c function as stops that restrict the movement of the finger body 42 in the second direction Y.

[0065] It should be noted that, as will be explained in detail later, the movement of the finger body 42 in the second direction Y towards the in-and-out side is restricted by the hand body 3 through the contact of the linkage mechanism 9, which is configured on the finger 4 and will be explained later, with the hand body 3.

[0066] In this way, the support 43 is elastically displaced in the second direction Y by the base 41. As a result, the finger body 42 is elastically displaced in the second direction Y by the support 43 and supported by the base 41. Furthermore, the finger body 42 is elastically displaced in the first direction X by the support 43. In other words, the finger body 42 is elastically displaced in the first direction X by the support 43 and supported by the base 41. It should be noted that in this example, when the support 43 moves in the second direction Y, the rocking shaft B also moves in the second direction Y.

[0067] =Fingers with a transmission belt=

[0068] like Figure 11As shown, finger 4 includes a first pulley 51, a second pulley 52, and a third pulley 53. The first pulley 51 is driven to rotate, the second pulley 52 is positioned at the front end of finger 4, and the third pulley 53 is positioned between the first pulley 51 and the second pulley 52. ​​An endless belt 5 is wound around the first pulley 51, the second pulley 52, and the third pulley 53. The first pulley 51 is the driving pulley, while the second pulley 52 and the third pulley 53 are the driven pulleys.

[0069] The finger body 42 rotatably supports each of the first pulley 51, the second pulley 52, and the third pulley 53 about mutually parallel axes of rotation. Specifically, as... Figure 9 As shown, the first pulley 51 is rotatably supported by the finger body 42 via a support shaft 44. The first pulley 51 cannot rotate relative to the support shaft 44. The support shaft 44 rotatably supports the finger body 42 about its axis, namely the rocking shaft B. As a result, the first pulley 51 can rotate relative to the finger body 42 about the rocking shaft B. It should be noted that the second pulley 52 and the third pulley 53 are also rotatably supported by the finger body 42 via shafts.

[0070] like Figure 11 As shown, the third pulley 53 is positioned near the tip of the finger 4, i.e., near the second pulley 52. ​​The third pulley 53 is positioned further away from the second pulley 52 on the closing side in the opening / closing direction A. That is, as... Figure 4 As shown, the spacing between the third pulleys 53 of the multiple fingers 4 is narrower than the spacing between the second pulleys 52 of the multiple fingers 4.

[0071] In this example, such as Figure 11 As shown, finger 4 also has a fourth pulley 54 and a fifth pulley 55. Finger body 42 rotatably supports each of the fourth pulley 54 and the fifth pulley 55. The fourth pulley 54 and the fifth pulley 55 are driven pulleys. The rotation axis of each of the fourth pulley 54 and the fifth pulley 55 is parallel to the rotation axis of the first pulley 51, etc. The fourth pulley 54 is disposed between the first pulley 51 and the third pulley 53. The fourth pulley 54 is disposed closer to the first pulley 51 than the third pulley 53. The fifth pulley 55 is disposed between the first pulley 51 and the second pulley 52. ​​However, the fifth pulley 55 is disposed more on the opening side in the opening / closing direction A than the first pulley 51 and the second pulley 52.

[0072] An endless belt 5 is disposed on the finger body 42. The endless belt 5 is wound around the first pulley 51, second pulley 52, third pulley 53, fourth pulley 54, and fifth pulley 55 from the outside. That is, the first pulley 51, second pulley 52, third pulley 53, fourth pulley 54, and fifth pulley 55 are disposed on the inside of the endless belt 5. The endless belt 5 is a toothed belt, i.e., a synchronous belt. The first pulley 51 and second pulley 52 are toothed pulleys, i.e., synchronous pulleys. The third pulley 53, fourth pulley 54, and fifth pulley 55 are toothed pulleys, functioning as toothed idler pulleys. The teeth of the endless belt 5 mesh with the teeth of the first pulley 51, etc.

[0073] The portion of the endless belt 5 between the first pulley 51 and the second pulley 52, which passes through the third pulley 53 and the fourth pulley 54, is the inner surface 4a of the finger 4. In the normal state, i.e., when no external force is applied in the first direction X, the portion of the endless belt 5 corresponding to the inner surface 4a extends in the second direction Y, toward the closing side of the opening and closing direction A. That is, as... Figure 4 As shown, the portion of the end band 5 of one finger 4 corresponding to the inner surface 4a and the portion of the end band 5 of another finger 4 corresponding to the inner surface 4a face each other. Strictly speaking, the portions of the end band 5 of one finger 4 corresponding to the inner surface 4a and the portions of the end band 5 of another finger 4 corresponding to the inner surface 4a are inclined towards the front end with a gap between them.

[0074] The portion of the endless belt 5 between the second pulley 52 and the third pulley 53 is inclined relative to the portion of the endless belt 5 between the third pulley 53 and the fourth pulley 54. Specifically, the portion of the endless belt 5 between the second pulley 52 and the third pulley 53 is inclined in a manner that approaches the tip of the finger 4 and is located on the opening side in the opening-closing direction A. That is, the front end of the inner surface 4a of the finger 4 is inclined in a manner that opens towards the opening side in the opening-closing direction A. As a result, the spacing between the plurality of fingers 4 at the front end of the finger 4 increases towards the tip of the finger 4.

[0075] like Figure 11 As shown, the finger 4 also has a plurality of rollers 56. The finger body 42 rotatably supports each of the plurality of rollers 56 about a rotation axis parallel to each other. The rotation axis of the rollers 56 is parallel to the rotation axis of the first pulley 51, etc. The plurality of rollers 56 are arranged inside the endless belt 5. The plurality of rollers 56 are arranged along the portion of the endless belt 5 between the third pulley 53 and the fourth pulley 54. Each roller 56 is close to the endless belt 5. In detail, each roller 56 has a gap between itself and the endless belt 5.

[0076] The endless belt 5 is rotated by the rotation of the first pulley 51. When the endless belt 5 rotates, the portion of the endless belt 5 corresponding to the inner surface 4a moves in the second direction Y. At this time, whether the portion of the endless belt 5 corresponding to the inner surface 4a moves towards the first end 42a side of the finger body 42 or towards the second end 42b side in the second direction Y depends on the direction of rotation of the first pulley 51. Hereinafter, the rotation when the portion corresponding to the inner surface 4a moves towards the first end 42a side is referred to as "rotation towards the delivery side", and the rotation when the portion corresponding to the inner surface 4a moves towards the second end 42b side is referred to as "rotation towards the pull-in side".

[0077] =Opening / closing actuator=

[0078] like Figure 5 As shown, the opening / closing actuator 7 has a first motor 71, a feed screw 72, and a transmission 75. The feed screw 72 is connected to a finger 4, and the transmission 75 transmits the rotational driving force of the first motor 71 to the feed screw 72. The opening / closing actuator 7 is disposed on the hand body 3.

[0079] The first motor 71 is, for example, a servo motor. Furthermore, a current sensor is provided in the driver of the first motor 71. The first motor 71 is mounted on the hand body 3 with its output shaft 71a parallel to the opening / closing direction A.

[0080] The feed screw 72 includes a screw 73 and a nut 74. In this example, the feed screw 72 includes two nuts 74. The screw 73 extends in the opening / closing direction A. The screw 73 is rotatably supported by the hand body 3 via a bearing about an axis extending in the opening / closing direction A. The screw 73 is a so-called left and right screw. The screw 73 includes a right screw portion and a left screw portion arranged coaxially.

[0081] Each nut 74 is screwed onto the screw 73. A nut 74 is connected to each finger 4. The nut 74 is fixed to the base 41 of the finger 4. By screwing the nut 74 onto the screw 73, the base 41 is supported by the feed screw 72, allowing it to move in the opening / closing direction A. One nut 74 is screwed onto the right screw portion of the screw 73, and the other nut 74 is screwed onto the left screw portion of the screw 73.

[0082] In addition, the base 41 is prevented from rotating about the axis of the screw 73 by the hand body 3. Specifically, when the base 41 is supported by the feed screw 72, as... Figure 5 As shown, the base 41 is located near the base plate 31 of the hand body 3. A slit 32 extending in the opening / closing direction A is formed on the base plate 31. The base 41 is fitted into the slit 32. Figure 8 As shown, an anti-detachment component 41b is installed on the base 41, which prevents the base 41 from detaching from the slit 32. Figure 3As shown, the anti-slip component 41b protrudes outward from the hand body 3. The base 41 cannot rotate around the axis of the screw 73 because it is embedded in the slit 32.

[0083] like Figure 5 As shown, the transmission 75 has a first pulley 75a, a second pulley 75b, and a timing belt 75c. The first pulley 75a is mounted on the output shaft 71a of the first motor 71, the second pulley 75b is mounted on a screw 73, and the timing belt 75c is wound around the first pulley 75a and the second pulley 75b. The first pulley 75a and the second pulley 75b are toothed pulleys, i.e., timing pulleys. The timing belt 75c is a toothed belt. The first pulley 75a is non-rotatably mounted on the output shaft 71a of the first motor 71. The second pulley 75b is non-rotatably mounted on the screw 73. The rotational driving force of the first motor 71 is transmitted from the first pulley 75a to the second pulley 75b via the timing belt 75c.

[0084] When the first motor 71 operates, the screw 73 rotates together with the second pulley 75. Since the base 41 fixed to the nut 74 is embedded in the slit 32 of the hand body 3, the nut 74 and the base 41 do not rotate even when the screw 73 rotates. The nut 74 and the base 41 move towards the axis of the screw 73 as the screw 73 rotates, resulting in the finger 4 moving in the opening / closing direction A.

[0085] One finger 4 is screwed into the right screw portion of the screw 73, and the other finger 4 is screwed into the left screw portion of the screw 73. Therefore, when the screw 73 rotates, the two fingers 4 move closer to each other in the opening / closing direction A (i.e., closed), or move away from each other in the opening / closing direction A (i.e., open). Whether the two fingers 4 are closed or open is switched by the direction of rotation of the screw 73, i.e., the direction of rotation of the first motor 71.

[0086] =Rotary Actuator=

[0087] like Figure 6 As shown, the rotary actuator 8 has a second motor 81 and a transmission 82. The second motor 81 outputs a rotational driving force for the pulley 51, and the transmission 82 transmits the rotational driving force of the second motor 81 to the first pulley 51. The second motor 81 is, for example, a servo motor. Furthermore, a current sensor is provided in the driver of the second motor 81. The second motor 81 is mounted on the hand body 3 with its output shaft 81a parallel to the opening / closing direction A.

[0088] The actuator 82 includes a first actuator 83 and a second actuator 84, the first actuator 83 being disposed on the hand body 3 and the second actuator 84 being disposed on the fingers 4.

[0089] The first transmission device 83 has a first pulley 83a, a second pulley 83b, a synchronous belt 83c, and a splined shaft 83d. The synchronous belt 83c is wound around the first pulley 83a and the second pulley 83b, and the splined shaft 83d is connected to the second pulley 83b. The first pulley 83a and the second pulley 83b are toothed pulleys, i.e., synchronous pulleys. The synchronous belt 83c is a toothed belt. The first transmission device 83 transmits the rotational driving force of the second motor 81 to the splined shaft 83d.

[0090] The first pulley 83a is non-rotatably connected to the output shaft 81a. The spline shaft 83d has a shaft C extending parallel to the opening / closing direction A. The spline shaft 83d is freely rotatable about the shaft C and is supported by the hand body 3. The second pulley 83b is non-rotatably connected to the spline shaft 83d.

[0091] like Figure 12 As shown, the second transmission device 84 has a helical gear 85, a first transmission pulley 86, and a second transmission pulley 87 (see reference). Figure 7 ), transmission belt 810 (refer to) Figure 8 The finger body 42 comprises a first idler wheel 88, a second idler wheel 89, and a linkage mechanism 9. A helical gear 85 is mounted on a base 41. A first drive pulley 86 is mounted on the base 41, and a second drive pulley 87 is mounted on the finger body 42. A drive belt 810 is wound around the first drive pulley 86 and the second drive pulley 87. The first idler wheel 88 and the second idler wheel 89 impart tension to the drive belt 810. The linkage mechanism 9 connects the base 41 and each of the finger body 42 and supports the first idler wheel 88 and the second idler wheel 89. A second transmission device 84 transmits the rotation of the spline shaft 83d to the first pulley 51 of the finger 4.

[0092] like Figure 11 As shown, the helical gear 85 includes a first gear 85a and a second gear 85b meshing with the first gear 85a. The first gear 85a is rotatable about shaft C but cannot move in the direction of shaft C and is supported by a base 41 of the finger 4. Specifically, the first gear 85a is connected to a spline shaft 83d, which is rotatable about shaft C but can move in the direction of shaft C. The second gear 85b is rotatable about shaft D and is supported by the base 41. Shaft D is positioned torsional relative to shaft C. Shaft D is parallel to the rotation axis of the first pulley 51, i.e., the rocking shaft B. Specifically, the base 41 rotatably supports shaft 85c about shaft D. The second gear 85b is not rotatable about shaft D and is supported by shaft 85c. That is, the second gear 85b is rotatable about shaft D and is supported by the base 41 via shaft 85c.

[0093] When the spline shaft 83d rotates around shaft C, the first gear 85a rotates integrally with the spline shaft 83d around shaft C. At this time, the base 41 does not rotate around shaft C. When the first gear 85a rotates, the second gear 85b rotates around shaft D.

[0094] like Figure 12 As shown, the first drive pulley 86 is rotatably supported by the base 41 about the shaft D. Specifically, the first drive pulley 86 is not rotatably supported by the rotating shaft 85c. The first drive pulley 86 is coaxially configured with the second gear 85b and rotates integrally with the second gear 85b about the shaft D.

[0095] like Figure 9 As shown, the second transmission pulley 87 is supported by the support shaft 44 without being able to rotate around its axis. As described above, while the support shaft 44 supports the first pulley 51 without being able to rotate around its axis, it can rotatably support the finger body 42 around its axis. That is, the second transmission pulley 87 can be rotatably supported by the finger body 42 via the support shaft 44 around its axis, i.e., the rocking shaft B. The second transmission pulley 87 is coaxially arranged with the first pulley 51 and rotates integrally with the first pulley 51 around the rocking shaft B. The rotation axis of the second transmission pulley 87 is parallel to the rotation axis of the first transmission pulley 86.

[0096] As shown in Figure 12, each of the first idler wheel 88 and the second idler wheel 89 is rotatably supported by the linkage mechanism 9 about a rotation axis parallel to the rotation axis of the first drive pulley 86 and the second drive pulley 87.

[0097] like Figure 13 As shown, the linkage mechanism 9 includes a first link 91, a second link 92, a third link 93, and a fourth link 94. The first link 91 rotatably supports the first idler wheel 88 and is rotatably connected to the base 41 about the axis D of the first drive pulley 86. The second link 92 rotatably supports the first idler wheel 88 and is rotatably connected to the finger body 42 about the axis B of the second drive pulley 87. The third link 93 rotatably supports the second idler wheel 89 and is rotatably connected to the finger body 42 about the axis B of the second drive pulley 87. The fourth link 94 rotatably supports the second idler wheel 89 and is rotatably connected to the base 41 about the axis D of the first drive pulley 86. In other words, the first idler wheel 88 is supported by the first link 91 and the second link 92. The second idler wheel 89 is supported by the third link 93 and the fourth link 94. In other words, the first link 91 connects the first drive pulley 86 and the first idler pulley 88. The second link 92 connects the first idler pulley 88 and the second drive pulley 87. The third link 93 connects the second drive pulley 87 and the second idler pulley 89. The fourth link 94 connects the second idler pulley 89 and the first drive pulley 86.

[0098] The first link 91 and the third link 93 are parallel to each other. The second link 92 and the fourth link 94 are parallel to each other. That is to say, the linkage mechanism 9 is a parallel linkage mechanism. In the parallelogram formed by the linkage mechanism 9, the first drive pulley 86 and the second drive pulley 87 are arranged at opposite corners on one side. The first idler pulley 88 and the second idler pulley 89 are arranged at opposite corners on the other side.

[0099] The first link 91, the second link 92, the third link 93, and the fourth link 94 are equilateral links. That is, the lengths of the first link 91, the second link 92, the third link 93, and the fourth link 94 are all the same.

[0100] The pitch circle diameters of each of the first drive pulley 86, the second drive pulley 87, the first idler pulley 88, and the second idler pulley 89 are the same.

[0101] The drive belt 810 is an endless belt. The drive belt 810 is wound around the first drive pulley 86, the second drive pulley 87, the first idler pulley 88, and the second idler pulley 89 from the outside. That is, the first drive pulley 86, the second drive pulley 87, the first idler pulley 88, and the second idler pulley 89 are arranged on the inside of the drive belt 810.

[0102] The transmission belt 810 is a toothed belt. The first transmission pulley 86 and the second transmission pulley 87 are toothed pulleys, i.e., synchronous pulleys. The first idler pulley 88 and the second idler pulley 89 are toothed pulleys, functioning as toothed idler pulleys. The teeth of the transmission belt 810 mesh with the teeth of the first transmission pulley 86, etc.

[0103] As described above, the finger body 42 is displaced relative to the base 41. For example, as Figure 14 As shown, the finger body 42 is displaced relative to the base 41 in the second direction Y. A first drive pulley 86 is disposed on the base 41, and a second drive pulley 87 is disposed on the finger body 42. The relative positional relationship between the first drive pulley 86 and the second drive pulley 87 changes in response to the displacement of the finger body 42 in the second direction Y. When the relative positional relationship between the first drive pulley 86 and the second drive pulley 87 changes, the linkage mechanism 9 deforms, and the first idler pulley 88 and the second idler pulley 89 supported by the linkage mechanism 9 are displaced. Even though the first idler pulley 88 and the second idler pulley 89 are displaced, the perimeter of the quadrilateral formed by the linkage mechanism 9 does not change. That is, the first idler pulley 88 and the second idler pulley 89 continue to impart appropriate tension to the drive belt 810 by displacing according to the linkage mechanism 9. In this way, the drive belt 810 appropriately transmits the rotation of the first drive pulley 86 to the second drive pulley 87.

[0104] It should be noted that the finger body 42 also displaces in the first direction X relative to the base 41. At this time, the finger body 42 shakes around the axis of the rocking shaft B, i.e., the supporting shaft 44. Since the first pulley 51 and the second transmission pulley 87 are supported by the supporting shaft 44, even if the finger body 42 shakes around the rocking shaft B, the first pulley 51 and the second transmission pulley 87 do not displace. As a result, the relative positional relationship between the first transmission pulley 86 and the second transmission pulley 87 does not change, and the linkage mechanism 9 does not deform. Therefore, the transmission belt 810 appropriately transmits the rotation of the first transmission pulley 86 to the second transmission pulley 87.

[0105] like Figure 6 As shown, in a rotary actuator 8 configured in this way, when the second motor 81 operates, the rotational driving force of the second motor 81 is transmitted from the first pulley 83a to the second pulley 83b via the synchronous belt 83c, and the spline shaft 83d rotates about the shaft C. When the spline shaft 83d rotates, the first gear 85a of the helical gear 85 rotates integrally with the spline shaft 83d. In response to this, as... Figure 12 As shown, when the second gear 85b rotates, the first transmission pulley 86 also rotates integrally with the second gear 85b. Figure 9 As shown, the rotation of the first drive pulley 86 is transmitted to the second drive pulley 87 via the drive belt 810, and the first pulley 51 and the second drive pulley 87 rotate together. Thus, the first pulley 51 is driven to rotate by the second motor 81, resulting in the rotation of the endless belt 5. It should be noted that the direction of rotation of the endless belt 5 is switched in response to the direction of rotation of the second motor 81.

[0106] Here, when finger 4 moves in the opening / closing direction A, the second actuator 84 moves integrally with finger 4 in the opening / closing direction A. Specifically, the first gear 85a is capable of moving relative to the spline shaft 83d in the direction of axis C. Since axis C is parallel to the opening / closing direction A, the first gear 85a, supported by the base 41, moves along the spline shaft 83d in response to the movement of finger 4 in the opening / closing direction A. Even when finger 4 moves in the opening / closing direction A, the first gear 85a remains supported by the spline shaft 83d without rotating around axis C. That is, regardless of the position of finger 4 in the opening / closing direction A, the rotational driving force of the second motor 81 is transmitted to the first gear 85a via the spline shaft 83d.

[0107] Furthermore, as described above, the finger body 42 of finger 4 is displaced in the first direction X. At this time, the finger body 42 oscillates around the axis of the rocking shaft B, i.e., the supporting shaft 44. The first pulley 51 and the second transmission pulley 87 are supported by the supporting shaft 44. Therefore, even if the finger body 42 oscillates around the rocking shaft B, the first pulley 51 and the second transmission pulley 87 do not displace. As a result, even if the finger body 42 displaces in the first direction X, the rotational driving force of the second motor 81 is transmitted to the second transmission pulley 87 via the transmission belt 810.

[0108] Furthermore, as described above, the finger body 42 of finger 4 is displaced in the second direction Y. At this time, the finger body 42 is displaced relative to the base 41 in the second direction Y. The first drive pulley 86 is disposed on the base 41, and the second drive pulley 87 is disposed on the finger body 42. Therefore, in response to the displacement of the finger body 42 in the second direction Y, the relative positional relationship between the first drive pulley 86 and the second drive pulley 87 changes. When the relative positional relationship between the first drive pulley 86 and the second drive pulley 87 changes, the first idler pulley 88 and the second idler pulley 89, supported by the linkage mechanism 9, are displaced. The first idler pulley 88 and the second idler pulley 89 continue to impart appropriate tension to the drive belt 810 by displacing according to the linkage mechanism 9. In this way, the drive belt 810 appropriately transmits the rotation of the first drive pulley 86 to the second drive pulley 87.

[0109] In summary, regardless of the movement of the finger 4 in the opening / closing direction A, the displacement of the finger body 42 in the first direction X, or the displacement of the finger body 42 in the second direction Y, the endless belt 5 is driven to rotate by the second motor 81.

[0110] It should be noted that, as Figure 2 As shown, linkage 9 is disposed within the hand body 3. Fourth linkage 94 is disposed near the base plate 31 of the hand body 3. The finger body 42 is subjected to force by spring 47 relative to the base 41 in the second direction Y towards the in-and-out side. When the finger body 42 moves in the second direction Y towards the in-and-out side, the fourth linkage 94 moves together with the finger body 42 in the second direction Y towards the in-and-out side. Finally, the second linkage 92 and the third linkage 93 contact the base plate 31. That is, the movement of the finger body 42 towards the in-and-out side in the second direction Y is limited by the contact of the second linkage 92 and the third linkage 93 towards the base plate 31. Alternatively, the movement of the finger body 42 towards the in-and-out side in the second direction Y can also be limited by the contact of the second linkage 92 and the fourth linkage 94.

[0111] =Sensor=

[0112] Sensor 210 detects the pulling of a workpiece W between multiple fingers 4. For example, as Figure 2As shown, sensor 210 is disposed on the hand body 3, located between multiple fingers 4. More specifically, as... Figure 3 As shown, sensor 210 is located at the center of the plurality of fingers 4 in the opening / closing direction A. Sensor 210 is a distance sensor. Specifically, sensor 210 detects the distance to an object present between the plurality of fingers 4. Sensor 210 detects the pulling of a workpiece W between the plurality of fingers 4. For example, sensor 210 can be a TOF (Time of Flight) distance sensor.

[0113] =Control Device=

[0114] Figure 15 This diagram illustrates the schematic hardware structure of the control device 100. The control device 100 controls the hand 2 and the robotic arm 10, enabling the hand 2 to perform various tasks, such as picking up objects. The robot system 1000 also includes a robot control device 120. The control device 100 and the robot control device 120 exchange signals and information. The control device 100 controls the hand 2 and the robotic arm 10 via the robot control device 120. The control device 100 outputs commands to the robot control device 120. The control device 100 also exchanges signals and information with the camera 15. In response to commands from the control device 100, the robot control device 120 controls the servo motors of the robotic arm 10 and the hand 2.

[0115] Images from camera 15 are input to control device 100. Control device 100 detects workpiece W based on the images. In addition, control device 100 generates a target path for robot 1 based on the detected workpiece W, and outputs commands corresponding to the generated target path to robot control device 120.

[0116] The robot control device 120 has a processor 121, a storage device 122 and a memory 123.

[0117] Processor 121 controls the entire robot control device 120. Processor 121 performs various calculations. For example, processor 121 is constructed using a processor such as a CPU (Central Processing Unit). Processor 121 can also be formed using MCU (Microcontroller Unit), MPU (Microprocessor Unit), FPGA (Field Programmable Gate Array), PLC (Programmable Logic Controller), system LSI, etc.

[0118] Storage device 122 stores programs and various data executed by processor 121. Storage device 122 is formed using non-volatile memory, HDD (hard disk drive), or SSD (solid-state drive), etc. Memory 123 temporarily stores data, etc. For example, memory 123 is formed using volatile memory.

[0119] The processor 121 controls the hand 2 and the robot arm 10 according to commands from the control device 100. Specifically, the processor 121 controls the servo motors of the robot arm 10, etc. At this time, the processor 121 performs feedback control or feedforward control on the servo motors.

[0120] The control device 100 has a processor 101, a storage device 102 and a memory 103.

[0121] Processor 101 controls the entire control device 100. Processor 101 performs various calculations. For example, processor 101 is constructed using a processor such as a CPU (Central Processing Unit). Processor 101 can also be constructed using MCU (Microcontroller Unit), MPU (Microprocessor Unit), FPGA (Field Programmable Gate Array), PLC (Programmable Logic Controller), system LSI, etc.

[0122] Storage device 102 stores various programs and data executed by processor 101. Storage device 102 is formed using non-volatile memory, HDD (hard disk drive), or SSD (solid-state drive), etc. Various programs enable control device 100 to perform various functions.

[0123] Memory 103 temporarily stores data, etc. For example, memory 103 is formed using volatile memory. Memory 103 stores images from camera 15.

[0124] Processor 101 causes hand 2 and robotic arm 10 to perform a pulling action, in which the tips of multiple fingers 4 contact the workpiece W, and the endless belt 5 pulls the workpiece W between the multiple fingers 4. During the pulling action, processor 101 causes hand 2 and robotic arm 10 to perform a searching action. The searching action is an action that changes the relative position of the tips of the multiple fingers 4 and the workpiece W while the multiple fingers 4 are spaced at a predetermined interval and the endless belt 5 is rotated. The change in the relative position of the tips of the multiple fingers 4 and the workpiece W can include changes in relative position in any direction, as long as the positional relationship between the tips of the multiple fingers 4 and the workpiece W changes.

[0125] Figure 16 This is a block diagram showing the structure of the control system of processor 101. Processor 101 implements various functions by reading programs from storage device 102 into memory 103 and expanding them. In detail, processor 101 functions as an image capture controller 104, a detector 105, a motion controller 106, and a decision maker 107. The image capture controller 104 enables camera 15 to acquire images, the detector 105 detects workpiece W, and the motion controller 106 causes the hand 2 and robot arm 10 to move.

[0126] The image capture controller 104 controls the camera 15 to acquire an image. The camera 15 acquires an image within the container 19. The image capture controller 104 causes the memory 103 to store the image from the camera 15.

[0127] Detector 105 detects the position of workpiece W from an image. The image may contain multiple workpieces W. Detector 105 detects the position of workpiece W from the image using arbitrary image processing. Detector 105 detects at least the approximate position of the workpiece W. It should be noted that detector 105 may not detect the exact position or orientation of the workpiece W. In this example, since randomly stacked workpieces W are objects, detector 105 can also detect the approximate position of the set of randomly stacked workpieces W.

[0128] Motion controller 106 controls robot arm 10, causing hand 2 to move towards a target position. Specifically, motion controller 106 generates a target path for robot arm 10 based on the detected position of workpiece W. Motion controller 106 outputs commands in response to the target path to robot control device 120. As described above, robot control device 120 controls servo motors according to commands to move robot arm 10 and hand 2 along the target path. During the pull-in action, motion controller 106 moves hand 2 to a position where the tips of multiple fingers 4 contact workpiece W. During the search action, motion controller 106 controls robot arm 10 in a manner that changes the relative position of the tips of multiple fingers 4 and workpiece W.

[0129] Regarding the control of hand 2, motion controller 106 controls the opening and closing of multiple fingers 4 and the rotation of the endless belt 5. Specifically, motion controller 106 controls the first motor 71 and the second motor 81 via robot control device 120. Motion controller 106 controls the first motor 71 to open and close the fingers 4. Motion controller 106 controls the first motor 71 to adjust the spacing of the multiple fingers 4 to a predetermined value. Motion controller 106 controls the second motor 81 to rotate the endless belt 5. More specifically, motion controller 106 switches the direction of rotation of the second motor 81 to switch whether the endless belt 5 pulls the workpiece W in or sends it out.

[0130] The judge 107 determines the pulling of the workpiece W between the multiple fingers 4 based on the detection result of the sensor 210. When the distance from the sensor 210 to the workpiece W is below a predetermined threshold, the judge 107 determines that the pulling of the workpiece W between the multiple fingers 4 has ended.

[0131] Furthermore, the detector 107 can also determine the approach of the finger 4 towards the workpiece W based on the detection result of the sensor 210. For example, the detector 107 determines that the finger 4 is in contact with the workpiece W when the distance from the sensor 210 to the workpiece W reaches a predetermined threshold. The threshold used to determine the contact of the finger 4 is greater than the threshold used to determine the pull into the workpiece W.

[0132] =Robot Actions=

[0133] Next, the actions of robot 1 will be described in detail. Robot 1 performs a pull-in grip, in which it grasps workpiece W by pulling it between multiple fingers 4 through an inward motion using the endless strap 5. During this pull-in grip, control device 100 causes hand 2 and robot arm 10 to perform a search action. Specifically, motion controller 106 rotates the endless strap 5 toward the pull-in side, causing the tips of multiple fingers 4 to contact workpiece W, and changes the relative position between the tips of multiple fingers 4 and workpiece W. The change in relative position is not only a monotonous decrease or increase in the relative distance between the tips of multiple fingers 4 and workpiece W, but also includes both a decrease and an increase in the relative distance. In this example, during the search action, control device 100 causes the tips of multiple fingers 4 to approach and move away from the set of randomly stacked multiple workpieces W, so that the tips of multiple fingers 4 contact any one of the multiple workpieces W. As the endless belt 5 rotates toward the pulling side, the workpiece W is pulled into the space between the fingers 4 by the endless belt 5 when the workpiece 4 is properly embedded between the fingers 4 at the front end of the multiple fingers 4.

[0134] Reference Figure 17 The pull-in grip of robot 1 is described in detail. Figure 17 This is a flowchart of the pick-and-place process.

[0135] First, in step S101, the image controller 104 acquires an image of the interior of the container 19. More specifically, the image controller 104 causes the camera 15 to acquire an image of the interior of the container 19.

[0136] In step S102, detector 105 detects the position of workpiece W from the image inside container 19. For example, detector 105 detects the approximate position of a set of randomly stacked workpieces W.

[0137] Furthermore, in step S103, the motion controller 106 begins searching for an action. Specifically, while adjusting the opening of the plurality of fingers 4, the motion controller 106 rotates the endless belt 5. In this state, the motion controller 106 changes the relative position of the tips of the plurality of fingers 4 and the workpiece W.

[0138] The control device 100 adjusts the spacing between the plurality of fingers 4 to a spacing smaller than the size of the workpiece W to be pulled in. Here, the spacing between the plurality of fingers 4 that the control device 100 can adjust is a spacing that can be controlled by the first motor 71 and is determined by the spacing between the plurality of bases 41. Since each finger 4 can be displaced in the first direction X, the spacing between the plurality of fingers 4 can be larger than the controlled spacing.

[0139] The control device 100 adjusts the spacing between the multiple fingers 4 to be a predetermined amount smaller than the size of the workpiece W to be pulled in. For example, the size of the workpiece W is the dimension of the portion of the workpiece W that is easier to grasp with the multiple fingers 4. When the workpiece W is a bolt, for example, the size of the workpiece W is the outer diameter of the bolt thread. When the workpiece W is a nut, for example, the size of the workpiece W is the thickness of the nut. The predetermined amount is less than the maximum increase in the spacing between the multiple fingers 4 due to the elastic displacement of the fingers 4 in the first direction X. That is, the spacing between the multiple fingers 4 is adjusted so that when the multiple fingers 4 elastically displace in the first direction X, the workpiece W to be pulled in can enter the spacing between the multiple fingers 4.

[0140] The change in the relative position of the tips of the multiple fingers 4 and the workpiece W can include changes in the relative position in any direction, as long as the positional relationship between the tips of the multiple fingers 4 and the workpiece W changes. For example, the motion controller 106, as a search action, causes the hand 2 to move back and forth by repeatedly approaching and moving away from the workpiece W with the tips of the multiple fingers 4. For example, the motion controller 106 periodically and repeatedly approaches and moves away from the multiple fingers 4 on the workpiece W. The direction of the back-and-forth movement of the hand 2 can be any direction.

[0141] Figure 18 This is a schematic diagram illustrating an example of the search action of hand 2. Figure 19 This is a schematic diagram showing the successful pulling of workpiece W. Figure 20 This is a schematic diagram illustrating the state of finger 4 when workpiece W is pulled in. For example, as... Figure 18 As shown, the motion controller 106 moves the hand 2 back and forth in the direction of the reference axis P while the reference axis P is facing the workpiece W. Since the fingers 4 extend in the direction of the reference axis P, the hand 2 moves in the direction of the extension of the fingers 4. That is, in this search action, the relative positions of the multiple fingers 4 in the direction of the reference axis P and the workpiece W are changed.

[0142] Since the approximate position of the randomly stacked workpieces W is determined by detector 105, motion controller 106 moves finger 4 closer to workpiece W until the tip of finger 4 reaches workpiece W in the direction of reference axis P. At this time, motion controller 106 moves finger 4 further towards workpiece W than the position of workpiece W detected by detector 105. Since multiple fingers 4 can elastically displace in the second direction Y, even if finger 4 contacts workpiece W, the impact on finger 4 is absorbed by the elastic displacement of finger 4 in the second direction Y. Thus, the tip of finger 4 contacts any one of the workpieces W. Furthermore, the elastic deformation of finger 4 in the second direction Y causes finger 4 to be elastically pressed against workpiece W. That is, finger 4 is pressed against workpiece W with appropriate force. It should be noted that motion controller 106 can also move finger 4 closer to workpiece W until the determiner 107 determines the arrival of the tips of multiple fingers 4 towards workpiece W based on the detection result of sensor 210.

[0143] Because the endless belt rotates in the 5-way pulling side, when the tip of any one of the multiple fingers 4 contacts the workpiece W, if the workpiece W is embedded between the tips of the multiple fingers 4, such as Figure 19 As shown, the workpiece W is pulled between multiple fingers 4 by an endless belt 5. By pulling the workpiece W between the multiple fingers 4, each finger 4 is elastically displaced in a first direction X, and the spacing between the multiple fingers 4 is automatically adjusted in response to the workpiece W.

[0144] In this example, when the workpiece W is not pulled in, the portions of the endless band 5 of one finger 4 corresponding to the inner surface 4a and the portions of the endless band 5 of another finger 4 corresponding to the inner surface 4a are inclined towards the front end, with the distance between them narrowing. As multiple fingers 4 pull the workpiece W in, each finger 4 elastically displaces in the first direction X, causing the portions of the endless band 5 of one finger 4 corresponding to the inner surface 4a and the portions of the endless band 5 of another finger 4 corresponding to the inner surface 4a to either become parallel or inclined towards the front end, with the distance between them widening.

[0145] In addition to the displacement of the fingers 4 in the first direction X, the endless belt 5 can also elastically deform. When the workpiece W is pulled between the multiple fingers 4, the endless belt 5 can elastically deform towards the open side of the fingers 4. The elastic deformation of the endless belt 5 also causes the spacing of the multiple fingers 4 to be automatically adjusted in response to the workpiece W. It should be noted that the endless belt 5 can deform to contact the roller 56. That is, the larger elastic deformation of the endless belt 5 is limited by the roller 56.

[0146] In addition, because the multiple fingers 4 independently and elastically displace in the second direction Y, the workpiece W can more easily contact the portion of the endless band 5 of any one finger 4 corresponding to the inner surface 4a. Specifically, as... Figure 20 As shown, depending on the contact state between the multiple fingers 4 and the workpiece W, the amount of elastic displacement in the second direction Y may differ among the multiple fingers 4. That is, the amount of elastic displacement of one finger 4 ( Figure 20 The left finger (4) is positioned further inward in the second direction Y compared to the other fingers (4). The portion of the endless band 5 of the finger (4) moving in the second direction Y, corresponding to the inner surface 4a, more easily contacts the workpiece W. As a result, it facilitates the pulling of the workpiece W between the multiple fingers (4).

[0147] As a search action, the motion controller 106 moves the finger 4 towards the workpiece W to a predetermined position, and then moves the tip of the finger 4 away from the workpiece W in the direction of the reference axis P. The motion controller 106 repeatedly approaches and moves away from the finger 4 towards the workpiece 4.

[0148] The motion controller 106 can also move the hand 2 by moving the front ends of multiple fingers 4 in a plane that intersects the pulling direction of the multiple fingers 4, i.e., in a plane that intersects the reference axis P. Figure 21 These are illustrations of other examples used to illustrate the search action of hand 2. For example, such as... Figure 21 As shown, the motion controller 106 moves the hand 2 by moving the tips of the multiple fingers 4 in a plane orthogonal to the pulling direction of the multiple fingers 4 (i.e., the reference axis P). It should be noted that the plane intersecting the pulling direction of the multiple fingers 4 is not limited to a plane, but also includes curved surfaces.

[0149] At this time, the motion controller 106 moves the hand 2 in a manner that moves the tips of the multiple fingers 4 within a plane intersecting the pull-in direction of the workpiece W while the tips of the multiple fingers 4 are in contact with or approaching the workpiece W. During this search action, the relative positions of the multiple fingers 4 and the workpiece W in the direction intersecting the pull-in direction of the workpiece W are changed. Preferably, the motion controller 106 moves the hand 2 while the tips of the multiple fingers 4 are placed into the set of workpieces W.

[0150] When the workpiece W is embedded between the tips of the fingers 4 during the movement of the multiple fingers 4, the workpiece W is pulled into the space between the fingers 4 by the endless strap 5. Even if the workpiece W is not embedded between the tips of the fingers 4, the position or posture of the workpiece W changes because the tips of the fingers 4 come into contact with the workpiece W. When the position or posture of the workpiece W changes, the workpiece W may be embedded between the tips of the fingers 4 or pulled into the space between the fingers 4.

[0151] Especially in a randomly stacked workpiece W, the movement of multiple fingers 4 within a plane intersecting the pulling directions of multiple fingers 4 can potentially change the workpiece W that is being pulled in. In other words, hand 2 attempts to pull in various workpieces W. This increases the probability that any workpiece W will be embedded between multiple fingers 4.

[0152] More specifically, the motion controller 106 causes the multiple fingers 4 to move in two dimensions within a plane intersecting the pulling directions of the multiple fingers 4. This movement within the plane intersecting the pulling directions of the multiple fingers 4, i.e., the two-dimensional movement viewed in the pulling direction, includes linear movement and curved movement. For example, the motion controller 106 can also cause the multiple fingers 4 to move in a zigzag, rotating, or reciprocating manner within the plane intersecting the pulling directions of the multiple fingers 4. Figure 22 This is a schematic diagram illustrating other examples of the search action of hand 2. For example, as a search action, the motion controller 106 can also move hand 2 by rotating the multiple fingers 4 around a predetermined rotation axis in a plane intersecting the pulling direction of the multiple fingers 4. The rotation axis can be either parallel to the reference axis P or not parallel to the reference axis P. Figure 22 In the example, the axis of rotation coincides with the reference axis P. It should be noted that the axis of rotation can also be an axis eccentric to the reference axis P. That is, rotation involves wrapping. Wrapping includes wrapping on various tracks such as circular tracks, spiral tracks, or polygonal tracks.

[0153] During the search operation, the motion controller 106 can also move the hand 2 in a manner that scans the multiple fingers 4 within a predetermined range within a plane intersecting the pulling directions of the multiple fingers 4. For example, the motion controller 106 sets a scanning range containing a set of workpieces W based on the multiple workpieces W detected by the detector 105. The motion controller 106 moves the hand 2 in a manner that the multiple fingers 4 move regularly or irregularly within the scanning range.

[0154] Alternatively, the motion controller 106 can move the hand 2 in a compound movement of multiple fingers 4, which is a combination of movement of multiple fingers 4 in the pull-in direction and movement of multiple fingers 4 in the direction intersecting the pull-in direction. For example, the motion controller 106 can also change the position of multiple fingers 4 in the direction intersecting the pull-in direction or change the angular position (i.e., rotation) of multiple fingers 4 around the reference axis P when the multiple fingers 4 approach or move away from the workpiece W.

[0155] When the search action begins, the determiner 107 determines in step S104 whether the pulling of the workpiece W between the multiple fingers 4 has ended. Since the endless belt 5 rotates towards the pulling side, when the workpiece W is embedded between the front ends of the multiple fingers 4, as... Figure 19As shown, workpiece W is pulled into the space between multiple fingers 4 by an endless strap 5. The determiner 107 judges the pulling status of workpiece W between the multiple fingers 4 based on the detection results of sensor 107. For example, a predetermined position in the pulling direction between the multiple fingers 4 is set as the end position of workpiece W's pulling. The determiner 107 detects whether workpiece W has reached the end position of pulling based on the detection results of sensor 210, and determines the end of the pulling of workpiece W by observing the arrival of workpiece W at the end position.

[0156] When none of the workpieces W are pulled between the multiple fingers 4, the motion controller 106 returns to step S103 to continue searching for motion.

[0157] In this manner, the motion controller 106 causes the tips of multiple fingers 4 to contact the workpiece W, attempting to pull the workpiece W in. By repeatedly changing the relative positions of the tips of the multiple fingers 4 and the workpiece W, the attempts to pull the workpiece W into the multiple fingers 4 are repeatedly attempted. Even if the pull-in of the workpiece W fails, the contact of the fingers 4 causes a change in the position or posture of the workpiece W. Therefore, in a subsequent attempt to pull the workpiece W in, it is possible for the workpiece W to become embedded between the tips of the multiple fingers 4. Thus, the motion controller 106, through repeated search actions, enables the workpiece W to be pulled into the multiple fingers 4.

[0158] When the hand 2 performs a search action by moving the tips of its multiple fingers 4 within a plane intersecting the pull-in direction of the fingers 4, the positions of the fingers 4 relative to the workpiece W within that plane are changed. Even if the positional accuracy of the fingers 4 relative to the workpiece W within the plane intersecting the pull-in direction is low, the search action can eventually bring the positions of the workpiece W and the fingers 4 into alignment. This simplifies the position control of the hand 2.

[0159] When the hand 2 moves in a search motion by rotating multiple fingers 4 around an axis parallel to the pull-in direction, the posture of the multiple fingers 4 relative to the workpiece W is changed. Ultimately, the posture of the multiple fingers 4 relative to the workpiece W can be changed so that the workpiece W is embedded in the tip of the multiple fingers 4.

[0160] In particular, among the randomly stacked workpieces W, contact with finger 4 towards workpiece W causes multiple workpieces W to move. During another attempt to pull in a workpiece W, it's possible to try pulling in a different workpiece W than before. In other words, hand 2 attempts to pull in various workpieces W. This increases the probability of successfully pulling in a workpiece W.

[0161] It should be noted that when the judgment device 107 determines, based on the detection result of the sensor 210, that the pulling of the workpiece W between the multiple fingers 4 has begun, the motion controller 106 can also temporarily stop the search action. That is to say, the motion controller 106 can also simply maintain the rotation of the endless belt 5 and temporarily stop the movement of the hand 2.

[0162] When the workpiece W is fully pulled in, the motion controller 106 terminates the search operation in step S105. Specifically, the motion controller 106 stops the rotation of the endless belt 5. In this way, the control device 100 terminates the search operation by detecting the pulling in of the workpiece W by the sensor 210.

[0163] Then, in step S106, the motion controller 106 causes the hand 2 and the robot arm 10 to move the workpiece W to the designated placement position. When the pick-up and placement process relative to a workpiece W is completed, the process of step S101 performed by the image controller 104 is executed again.

[0164] In this pick-and-place process, the control device 100 changes the relative position of the tips of multiple fingers 4 and the workpiece W through a search action, repeatedly attempting to pull the workpiece W between the multiple fingers 4. The control device 100 pulls the workpiece W between the multiple fingers 4 by continuing the search action. During the search action, the control device 100 does not open or close the multiple fingers 4 as controlled by the first motor 71. That is, the control device 100 keeps the spacing of the multiple fingers 4 constant during the search action. Through repeated search actions, the multiple fingers 4 naturally grasp the workpiece W pulled between the multiple fingers 4. The control device 100 can pull the workpiece W between the multiple fingers 4 even without high-precision position control of the fingers 4. Since high-precision position control of the fingers 4 is not required, high resolution of the camera 15 and high detection function of the detector 105 are also not required.

[0165] In detail, as a search action, hand 2 moves back and forth by repeatedly approaching and moving away from the tip of multiple fingers 4 relative to the workpiece W. Even if the workpiece W is not embedded between the tip of multiple fingers 4, the repeated approaching and moving away from the multiple fingers causes the relative position and posture of the workpiece W relative to the multiple fingers 4 to change. As a result, the workpiece W can eventually be embedded between the tip of multiple fingers 4.

[0166] During the search operation, hand 2 can also move by moving the tips of multiple fingers 4 within a plane that intersects with the pulling direction of the multiple fingers 4. In other words, as long as the relative position of the tips of the multiple fingers 4 and the workpiece W changes during the search operation, the movement of hand 2 can be arbitrary.

[0167] Because hand 2 has sensor 210, which detects the pulling of workpiece W between the multiple fingers 4, control device 100 can easily determine whether the workpiece W is being pulled between the multiple fingers 4. In other words, control device 100 can determine whether to continue or terminate the search action based on the detection result of sensor 210.

[0168] Hand 2 performs this pull-in grip relative to a set of multiple randomly stacked workpieces W. The control device 100 can pull any one of the multiple workpieces W between the multiple fingers 4 by having the fingers 4 contact the multiple workpieces W, even without specifying a single workpiece W.

[0169] Furthermore, since finger 4 is flexible in both the first direction X and the second direction Y, as described above, it is easier to achieve a pull-in grip. In other words, the flexibility of finger 4 increases the tolerance for positional accuracy during control, resulting in simplified and faster control of hand 2. For example, when bringing finger 4 close to workpiece W, by moving hand 2 in the second direction Y, even if finger 4 interferes with workpiece W or other objects, hand 4 can elastically displace in the second direction Y. Therefore, the tolerance for positional error of hand 2 when bringing finger 4 close to workpiece W increases. Alternatively, even if the opening of finger 4 is not strictly consistent with the size of workpiece W when gripping workpiece W, since finger 4 displaces in the first direction X in response to the size of workpiece W, it is still possible to properly grip workpiece W with finger 4. Therefore, the tolerance for positional error of finger 4 in the opening and closing directions when gripping workpiece W increases. In this way, the tolerance for both the positional accuracy of finger 4 when it approaches other objects containing workpiece W and the positional accuracy of finger 4 in the opening and closing direction when holding workpiece W is increased. Since the required accuracy for the position of finger 4 can be reduced, the control of hand 2 can be made easier, thereby enabling high-speed control.

[0170] Furthermore, the portion of the endless band 5 corresponding to the tip of the finger 4 is inclined in a manner that widens towards the tip of the finger 4 at intervals between the multiple fingers 4. This inclined portion of the endless band 5 functions as a guide to pull the workpiece W between the multiple fingers 4. By using the multiple fingers 4 with such wide intervals at the tip to perform a searching action, it is easy to randomly pull the workpiece W between the multiple fingers 4.

[0171] To achieve flexibility in finger 4, finger body 42 is elastically displaceable in a first direction X and elastically displaceable in a second direction Y, supported by base 41. Even with this structure, the rotational driving force of second motor 81 can be appropriately transmitted to endless belt 5 by transmission 82. Specifically, endless belt 5 is wound around first pulley 51 and second pulley 52 disposed on finger body 42. When finger body 42 is displaced relative to base 41, endless belt 5, first pulley 51, and second pulley 52 are also displaced relative to base 41. Even with displacement of finger body 42, rotational driving force is transmitted to first pulley 51 by transmission 82. In this way, even with a structure where the drive source of endless belt 5 is not disposed on finger body 42, rotational driving of endless belt 5, which is disposed on finger body 42 displaced relative to base 41, is possible. Since the drive source is not disposed on finger body 42, the structure of finger body 42 can be simplified and made lighter.

[0172] More specifically, the transmission device 82 includes a first transmission pulley 86, a second transmission pulley 87, and a transmission belt 810. The first transmission pulley 86 is disposed on the base 41, the second transmission pulley 87 is disposed on the finger body 42, and the transmission belt 810 is wound around the first transmission pulley 86 and the second transmission pulley 87. That is, the transmission device 82 includes a belt drive mechanism. In conjunction with the relative displacement of the finger body 42 relative to the base 41, the second transmission pulley 87 is displaced relative to the first transmission pulley 86, and the transmission belt 810 transmits rotational driving force from the first transmission pulley 86 to the second transmission pulley 87. In this way, the transmission belt 810 flexibly corresponds to the relative displacement of the finger body 42, transmitting rotational driving force from the base 41 to the finger body 42.

[0173] In particular, the pivot axis B of the finger body 42 relative to the base 41 and the axis of the second transmission pulley 87 are aligned. Therefore, even if the finger body 42 is pivoted, the relative position of the second transmission pulley 87 relative to the base 41, i.e., the relative position of the second transmission pulley 87 relative to the first transmission pulley 86, does not change. The transmission belt 810 can transmit the rotation of the first transmission pulley 86 to the second transmission pulley 87 without being affected by the pivoting of the finger body 42, i.e., the displacement of the finger body 42 in the first direction X.

[0174] Furthermore, the finger body 42 is supported by the base 41 and can oscillate around the axis of the first pulley 51. Even if the finger body 42 oscillates, the axis of the first pulley 51 does not shift. The axis of the first pulley 51 is also aligned with the oscillation axis B of the finger body 42 and the axis of the second transmission pulley 87. In other words, even if the finger body 42 shifts in the first direction X, since the axes of the first pulley 51 and the second transmission pulley 87 do not shift, there is no impact on the transmission belt 810.

[0175] The supporting shaft 44 rotatably supports the first pulley 51 and swayably supports the finger body 42. That is, the shaft that rotatably supports the first pulley 51 and the shaft that swayably supports the finger body 42 are the same. In this way, the structure of the finger 4 can be made compact.

[0176] In addition, the transmission 82 includes a first idler pulley 88 and a second idler pulley 89 that impart tension to the transmission belt 810. Even if the second transmission pulley 87 is displaced relative to the first transmission pulley 86, the tension of the transmission belt 810 is properly maintained by the first idler pulley 88 and the second idler pulley 89. Therefore, even if the finger body 42 is displaced in various directions relative to the base 41, the rotational driving force is properly transmitted to the finger body 42 by the transmission belt 810.

[0177] Furthermore, the first idler pulley 88 and the second idler pulley 89 are supported by a linkage mechanism 9, which is connected to each of the base 41 and the finger body 42. Since the first idler pulley 88 and the second idler pulley 89 are supported by the linkage mechanism 9, in response to the relative displacement of the finger body 42, the first idler pulley 88 and the second idler pulley 89 also displace, and the tension of the drive belt 810 is maintained.

[0178] In detail, the linkage 9 is a so-called four-bar linkage. The first drive pulley 86 and the second drive pulley 87 are positioned diagonally opposite each other on one side, and the first idler pulley 88 and the second idler pulley 89 are positioned diagonally opposite each other on the other side. When the first drive pulley 86 and the second drive pulley 87 approach each other, the first idler pulley 88 and the second idler pulley 89 move away from each other. When the first drive pulley 86 and the second drive pulley 87 move away from each other, the first idler pulley 88 and the second idler pulley 89 approach each other. In this way, the tension of the drive belt 810 is maintained.

[0179] Furthermore, the pitch circle diameters of each of the first drive pulley 86, the second drive pulley 87, the first idler pulley 88, and the second idler pulley 89 are identical. Therefore, the reaction force of the tension in the portion of the drive belt 810 wound around each pair of adjacent pulleys acts in the direction of the axis connecting those two pulleys. In other words, the reaction force of the tension in the drive belt 810 does not act as a torque around the axis of each pulley. As a result, since the reaction force of the tension in the drive belt 810 does not act as a force causing displacement of the finger body 42, the position of the finger body 42 remains stable.

[0180] In this finger 4, a torsion spring 45, which applies force to the finger body 42 in the first direction X toward the closed side of the finger 4, is configured such that its axis is located off-center from the axis of the first pulley 51. When a force is applied to the finger body 42 in the rocking direction by the torsion spring, the axis of the torsion spring tends to be concentrically aligned with the center of rocking of the finger body 42, which is rockably supported by the base 41. In this example, the center of rocking of the finger body 42 is the axis of the first pulley 51. However, by configuring the axis of the torsion spring 45 off-center from the axis of the first pulley 51, the number of components arranged in the direction of the axis of the first pulley 51 can be reduced. In this way, the size of the finger 4 in the direction of the axis of the first pulley 51 can be miniaturized.

[0181] <Variation Example>

[0182] Next, a variation of the robot system 1000 will be described. In the variation of the robot system 1000, the control device 100 moves the hand 2 and the robot arm 10 to a predetermined position to perform a search action without detecting the workpiece W through image recognition.

[0183] In detail, in the robot system 1000, the approximate location of the workpiece W is determined. For example, the workpiece W is positioned within a specified range, specifically within the container 19. Therefore, the control device 100 moves the hand 2 and the robot arm 10 to a specified position corresponding to the workpiece W, thereby performing a search operation. For example, the center of the container 19 in plan view and a specified depth position within the container 19 are set as the starting position for the search operation. The control device 100 moves the hand 2 and the robot arm 10 to the starting position, and then performs the search operation. At this time, since the control device 100 does not need to know the exact position of the workpiece W, it does not perform workpiece W detection. Therefore, the robot system 1000 does not include the camera 15. The processor 101 of the control device 100 does not have an image controller 104 or a detector 105.

[0184] Since the workpiece W can be grasped even without specifying its exact position by performing the search action, the detection of the workpiece W is unnecessary. Furthermore, the positional accuracy of the hand 2 and the robot arm 10 is also reduced. As a result, control for pulling in the workpiece W becomes easier.

[0185] Furthermore, in the robot system 1000 involved in the modified example, the control device 100 moves the hand 2 and the robot arm 10 along a predetermined target path without performing path planning for the search action, thereby realizing the search action.

[0186] In detail, when the approximate position of workpiece W is fixed, the target path of the robotic arm 10 is preset. The target path is set so that the hand 2 and the robot 1 move towards the approximate position of workpiece W to perform a search action. Since the approximate position of workpiece W is fixed, the target path remains constant. Therefore, the control device 100 does not perform path planning every time workpiece W is picked up. The control device 100 moves the hand 2 and the robotic arm 10 along the predetermined target path to perform the search action. It should be noted that during the initial pick-up, the control device 100 can also perform path planning based on the approximate position of workpiece W. In subsequent pick-ups, the control device 100 moves the hand 2 and the robotic arm 10 along the preset target path.

[0187] Since the search action is performed by moving hand 2 to the approximate position of workpiece W, it is possible to grasp workpiece W, thus eliminating the need for path planning corresponding to each workpiece W. As a result, it becomes easier to control the pulling of workpiece W.

[0188] As another variation, the robot system 1000 can detect the workpiece W using methods other than image detection. For example, the robot system 1000 can also detect the position of the workpiece W using sensor 210. That is, since the workpiece W is housed in container 19, its approximate two-dimensional position is known. The control device 100 detects the position of the workpiece W in the depth direction of container 19 based on the detection results of sensor 210. Specifically, the detector 105 of the control device 100 detects the approximate position of the workpiece W based on the detection results of sensor 210. The motion controller 106 generates a target path for the robot arm 10 based on the detected position of the workpiece W.

[0189] Even with only a rough detection of the workpiece W by sensor 210, the workpiece W can be pulled into the finger 4 by performing a search action. Since complex processing such as image recognition is not required, the control of pulling in the workpiece W becomes easy.

[0190] Other Implementation Methods

[0191] As described above, the embodiments described herein have been presented as examples of the technology disclosed in this application. However, the technology disclosed herein is not limited to this and can be applied to embodiments with appropriate modifications, substitutions, additions, omissions, etc. Furthermore, the various constituent elements described in the embodiments can be combined to form new embodiments. Moreover, the constituent elements described in the drawings and detailed descriptions include not only those necessary to solve the problem, but also, for the purpose of illustrating the technology, constituent elements that are not necessary to solve the problem. Therefore, one should not immediately assume that those non-essential constituent elements are essential simply because they are described in the drawings and detailed descriptions.

[0192] For example, the number of fingers 4 included in hand 2 can also be 3 or more.

[0193] The structure in which finger 4 can elastically displace in the first direction X is not limited to the structure described above. Similarly, the structure in which finger 4 can elastically displace in the second direction Y is not limited to the structure described above. As long as finger 4 can elastically displace in both the first direction X and the second direction Y, hand 2 can adopt any structure. For example, regarding the first direction X, finger body 42 may not be able to elastically displace in an arc-shaped direction centered on the rocking axis B, but rather in an opening / closing direction A. For example, the base 41 of finger 4 may slidably support finger body 42 in the opening / closing direction A, and finger body 42 may be forceped relative to the base 41 on the closing side in the opening / closing direction A by an elastic member such as a spring. As described above, the base 41 is movably supported by hand body 3 in the opening / closing direction A and driven in the opening / closing direction A by opening / closing actuator 7. Finger body 42 elastically displaces relative to base 41 in the opening / closing direction A. In this case, the first direction X differs from the arc-shaped direction around the rocking axis B described above, becoming a straight line direction in the opening / closing direction A.

[0194] Regarding the second direction Y, the hand body 3 can also be elastically supported relative to the robot arm 10 in the second direction Y. More specifically, the hand 2 can also have elastic components such as guides and springs, the guides slidably supporting the hand body 3 relative to the robot arm 10 in the second direction Y, and the elastic components such as springs applying force to the hand body 3 relative to the robot arm 10 in the second direction on the in-and-out side.

[0195] In the hand 2 in which the finger body 42 is supported by elastic displacement in a straight line relative to the base 41 in the opening and closing direction A, the second direction Y can be either the finger body 42 being supported by elastic displacement in the second direction Y relative to the base 41, or the hand body 3 being supported by elastic displacement in the second direction Y relative to the robot arm 10.

[0196] The transmission devices 75 and 82 are not limited to the structures described above. The transmission devices 75 and 82 can be modified to correspond to the structure of the finger 4. For example, the transmission device 82 can be any structure in response to the structure of the finger 4, which is elastically displaceable in the first direction X and the second direction Y. The transmission device 82 can also replace the belt and pulley, or, in addition to the belt and pulley, include a gear train, as long as the rotational driving force is transmitted to the first pulley 51.

[0197] The control device 100 may also not control the camera 15. For example, the control device 100 may receive images of the container 19 from the outside instead of from the camera 15. Alternatively, the camera 15 may be mounted on the robotic arm 10. In that case, the control device 100 controls the robotic arm 10 to move the camera 15 to the appropriate shooting position while the camera 15 is acquiring an image.

[0198] The image used by the control device 100 to detect the workpiece W can be a two-dimensional image. Since the positional accuracy of the finger 4 relative to the workpiece W can be relatively low during the search operation, the detection accuracy of the workpiece W can also be relatively low. Therefore, the detection of the workpiece W can also be based on a two-dimensional image.

[0199] The robot control device 120 may also be integrated with the control device 100, rather than being configured separately. In other words, the control device 100 may also have the functions of the robot control device 120.

[0200] The endless belt 5 may not be a synchronous belt. The first pulley 51 and the second pulley 52 may also not be synchronous pulleys. That is to say, the endless belt 5, the first pulley 51, and the second pulley 52 can also transmit rotation through friction.

[0201] Sensor 210 is not limited to a TOF (Time-of-Flight) distance sensor. For example, sensor 210 could also be a triangulation distance sensor. Sensor 210 is not limited to a distance sensor. For example, sensor 210 could also be a current sensor or a torque sensor installed in the rotary actuator 8. The control device 100 can determine an increase in the rotational resistance of the unendured belt 5 based on the detection results of the current sensor or torque sensor. The control device 100 can determine, based on the increase in the rotational resistance of the unendured belt 5, that the workpiece W is being pulled between the multiple fingers 4. Alternatively, sensor 210 could also be a sensor that detects the workpiece W contacting a lever or other component positioned between the multiple fingers 4.

[0202] The control device 100 may also select a specific workpiece W as the target workpiece W instead of multiple workpieces W during the search operation, allowing the tips of multiple fingers 4 to contact the workpiece W. For example, the individual workpieces W may be distributed within the container 19.

[0203] The bottom of container 19 may not be flat, but rather a concave curved surface. In other words, container 19 can also be shaped like a mortar and pestle. In this case, even if the contact of finger 4 during the search action causes workpiece W to move, workpiece W will naturally move to the bottom of container 19 after finger 4 leaves it. That is, even with repeated search actions, workpiece W will return to its designated position in container 19, thus eliminating the need to drastically change the position of finger 4 during the search action.

[0204] The direction of the back-and-forth movement of hand 2 in the search action can also be a direction that is not parallel to the reference axis P, that is, a direction that intersects the reference axis P.

[0205] The determination of whether workpiece W is pulled in can be synchronized with or asynchronous with the moment when finger 4 approaches and moves away from workpiece W. For example, control device 100 can also determine whether workpiece W is pulled in after finger 4 has finished approaching workpiece W, and if workpiece W is not pulled in, it can cause finger 4 to move away from workpiece W. Alternatively, control device 100 can cause finger 4 to repeatedly approach and move away from workpiece W, and perform the determination of whether workpiece W is pulled in regardless of the timing of approach and move away.

[0206] A flowchart is just one example. The steps in a flowchart can be modified, replaced, added, or omitted as appropriate. Furthermore, the order of the steps in the flowchart can be changed, or sequential processes can be processed in parallel. For example, when the position of workpiece W is known, steps S101 and S102 can be omitted.

[0207] The functions implemented by the constituent elements described in this specification can also be implemented in a circuit or processing circuitry that includes a general-purpose processor, a special-purpose processor, an integrated circuit, ASICs (Application Specific Integrated Circuits), a CPU (a Central Processing Unit), conventional circuitry, and / or combinations thereof, all programmed to implement the described functions. A processor includes transistors and other circuitry and is considered as a circuit or processing circuitry. A processor can also be a programmable processor that executes a program stored in memory.

[0208] In this specification, circuit, unit, and device are hardware programmed or executing to achieve the described function. This hardware may also be any hardware disclosed in this specification or any well-known hardware programmed or executing to achieve the described function.

[0209] When the hardware is a processor of the type of circuit, the circuit, device, or unit is a combination of hardware and software used to constitute the hardware and / or the processor.

[0210] [Way]

[0211] The implementation method is a specific example of the following approach.

[0212] (Method 1) The robot system 1000 includes a hand 2, a robot arm 10, and a control device 100. The robot arm 10 is connected to the hand 2, and the control device 100 controls the hand 2 and the robot arm 10. The hand 2 has a hand body 3 and a plurality of fingers 4 disposed on the hand body 3 and capable of opening and closing. Each of the plurality of fingers 4 has an endless band 5, which is wrapped around at least the front end of the finger 4, is rotated, and contacts the workpiece W.

[0213] When the control device 100 causes the tips of the plurality of fingers 4 to contact the workpiece W and the endless belt 5 to pull the workpiece W between the plurality of fingers 4, the hand 2 and the robot arm 10 perform a search action to change the relative position of the tips of the plurality of fingers 4 and the workpiece W while the plurality of fingers 4 are spaced apart and the endless belt 5 is rotated.

[0214] According to this structure, the contact manner between the tips of the multiple fingers 4 and the workpiece W can be changed through a search action. As a result, when the workpiece W is properly embedded between the tips of the multiple fingers 4, the workpiece W is pulled between the multiple fingers 4 by the endless strap 5. In this way, the probability of the workpiece W being properly embedded between the tips of the multiple fingers 4 can be increased through the search action. The workpiece W can be grasped by controlling the approximate position of the hand 2 through the search action. Since the positional accuracy of the hand 2 is not required, high-precision detection of the workpiece W is also unnecessary. That is, control of the hand 2 used to grasp the workpiece W and the robot arm 10 becomes easier.

[0215] (Method 2) In the robot system 1000 described in Method 1, the control device 100, as the search action, causes the hand 2 to move back and forth by repeatedly approaching and moving away from the workpiece W with the tips of the plurality of fingers 4.

[0216] According to this structure, even if the workpiece W is not embedded between the tips of the multiple fingers 4 during a single contact with the workpiece W, the relative position and posture of the workpiece W relative to the multiple fingers 4 change through repeated approaching and moving away from the multiple fingers 4. As a result, the possibility of the workpiece W embedding between the tips of the multiple fingers 4 is increased.

[0217] (Method 3) In the robot system 1000 described in Method 1 or Method 2, the control device 100 moves the hand 2 in such a way that the tips of the plurality of fingers 4 move in a plane that intersects with the pulling direction that pulls the workpiece W into the plurality of fingers 4 as the search action.

[0218] According to this structure, the positions of the tips of the multiple fingers 4 relative to the workpiece W are changed in the plane intersecting the pulling direction. Even if the positions of the multiple fingers 4 deviate from the workpiece W in the plane intersecting the pulling direction, the positions of the workpiece W and the multiple fingers 4 can eventually be made consistent through a search action.

[0219] (Method 4) In the robot system 1000 described in any one of Methods 1 to 3, the control device 100 moves the hand as the search action in such a way that the plurality of fingers rotate about an axis parallel to the pull-in direction in a plane intersecting the pull-in direction.

[0220] According to this structure, the posture of the multiple fingers 4 relative to the workpiece W is changed. As a result, the posture of the multiple fingers 4 relative to the workpiece W can be changed so that the workpiece W is ultimately embedded in the front ends of the multiple fingers 4.

[0221] (Method 5) In the robot system 1000 described in any one of Methods 1 to 4, the control device 100 moves the hand 2 and the robot arm 10 to a predetermined position without performing the detection of the workpiece W, thereby performing the search action.

[0222] According to this structure, since the detection of workpiece W is not required, the control for pulling in workpiece W becomes easier. The control device 100 can grasp workpiece W by moving hand 2 to a general position of workpiece W and performing a search action.

[0223] (Method 6) In the robot system 1000 described in any of Methods 1 to 5, the control device 100 moves the hand 2 and the robot arm 10 along a predetermined target path to perform the search action without performing path planning for the search action.

[0224] According to this structure, since path planning is not required, the control for pulling in the workpiece W becomes easier. The control device 100 can grasp the workpiece W by moving the hand 2 to a general position of the workpiece W along a predetermined target path and performing a search action.

[0225] (Method 7) In the robot system 1000 described in any of Methods 1 to 6, the hand 2 further has a sensor 210 that detects the pulling of the workpiece W between the plurality of fingers 4, and the control device 100 terminates the search action by detecting the pulling of the workpiece W by the sensor 210.

[0226] According to this structure, the end of the pulling of the workpiece W can be detected by the sensor 210. The pulling of the workpiece W between the multiple fingers 4 is successful. Since the pulling of the workpiece W between the multiple fingers 4 can be accurately determined by setting the sensor 210, the end of the search action can be determined.

[0227] (Method 8) In the robot system 1000 described in any one of Methods 1 to 7, the finger 4 is elastically displaced in a first direction X toward the opening and closing of the plurality of fingers 4.

[0228] According to this structure, when the workpiece W is pulled between the multiple fingers 4, the spacing of the multiple fingers 4 is adjusted in response to the size of the workpiece W by the elastic displacement of the fingers 4 in the first direction X. This increases the tolerance for the accuracy of the spacing between the multiple fingers 4. As a result, the control of the hand 2 can be simplified and accelerated.

[0229] (Method 9) In the robot system 1000 described in any of Methods 1 to 8, the prescribed interval of the plurality of fingers 4 in the search action is less than the size of the workpiece W to be pulled in.

[0230] According to this structure, when the workpiece W is pulled between the multiple fingers 4, the fingers 4 elastically displace in the first direction X, thereby widening the gap between the multiple fingers 4. The elastic force from the first direction X acts on the workpiece W between the multiple fingers 4. As a result, the multiple fingers 4 can firmly grip the workpiece W.

[0231] (Method 10) In the robot system 1000 described in any one of Methods 1 to 9, the finger 4 is capable of elastic displacement in a second direction Y that intersects the opening and closing direction of the finger 4.

[0232] According to this structure, since multiple fingers 4 can elastically displace in the second direction Y, the positional accuracy of the fingers 4 relative to the workpiece W in the second direction Y can be mitigated. For example, even if the fingers 4 move excessively relative to the workpiece W when they come into contact with it, the mutual impact between the fingers 4 and the workpiece W can be mitigated by the elastic displacement of the fingers 4 in the second direction Y. Since the tolerance for positional accuracy when the fingers 4 approach the workpiece W is increased, the control of the hand 2 can be simplified or accelerated. In addition, even if the detection accuracy of the position of the workpiece W is low, the workpiece W can be held by the fingers 4. Alternatively, if the approximate position of the workpiece W is known, the workpiece W can be held by the fingers 4 even without strict detection of the position of the workpiece W. These results make the control of the hand 2 easier.

[0233] (Method 11) In the robot system 1000 described in any one of Methods 1 to 10, the control device 100, during the search action, brings the tips of a plurality of fingers 4 close to a set of a plurality of randomly stacked workpieces W, so that the tips of the plurality of fingers 4 contact any one of the plurality of workpieces W.

[0234] According to this structure, the control device 100 can pull any one of the multiple workpieces W between the multiple fingers 4 by bringing the fingers 4 close to the set of multiple workpieces W, even without determining which workpiece W is being targeted. Therefore, strict detection of the position of the workpiece W is unnecessary, and even when detecting the position of the workpiece W, the detection accuracy can be reduced. In particular, when the approximate position of the workpiece W is known, detection of the workpiece W is not required. Furthermore, since it is only necessary to bring the fingers 4 to the set of workpieces W, the positional accuracy of the hand 2 can be reduced.

Claims

1. A robot system characterized by comprising a hand, a robot arm to which the hand is attached, and a control device to control the hand and the robot arm, the hand having a hand body and a plurality of fingers provided to the hand body and performing opening and closing actions, each of the plurality of fingers having an endless belt wound around at least a tip of the finger, rotationally driven, and brought into contact with a workpiece, the control device, when the tips of the plurality of fingers are brought into contact with a workpiece and the workpiece is drawn into between the plurality of fingers by the endless belt, causing the plurality of fingers to open a prescribed interval and the endless belt to rotate, causing the hand and the robot arm to perform a search action to change relative positions of the tips of the plurality of fingers and the workpiece.

2. The robot system according to claim 1, characterized in that the control device, as the search action, causes the hand to perform reciprocating movement in a manner that the tips of the plurality of fingers repeatedly approach and depart from the workpiece.

3. The robot system according to claim 1, characterized in that the control device, as the search action, causes the hand to move in a manner that the tips of the plurality of fingers move in a plane intersecting with a drawing-in direction in which the workpiece is drawn into between the plurality of fingers.

4. The robot system according to claim 3, characterized in that the control device, as the search action, causes the hand to move in a manner that the plurality of fingers rotate around an axis parallel to the drawing-in direction in the plane intersecting with the drawing-in direction.

5. The robot system according to claim 1, characterized in that the control device, without performing detection of the workpiece, causes the hand and the robot arm to move to a predetermined position, causing the search action to be performed.

6. The robot system according to claim 1, characterized in that the control device, without performing path planning for the search action, causes the hand and the robot arm to move along a predetermined target path, causing the search action to be performed.

7. The robot system according to any one of claims 1 to 6, characterized in that the robot system further comprises a sensor to detect drawing-in of the workpiece into between the plurality of fingers, the control device ending the search action by detecting the drawing-in of the workpiece by the sensor.

8. The robot system according to any one of claims 1 to 6, characterized in that the fingers are elastically displaceable in a first direction in which the plurality of fingers open and close.

9. The robot system according to claim 8, characterized in that the prescribed interval of the plurality of fingers in the search action is smaller than a size of a workpiece to be drawn in.

10. The robot system according to any one of claims 1 to 6, characterized in that the fingers are elastically displaceable in a second direction intersecting with a direction in which the fingers open and close.

11. The robot system according to any one of claims 1 to 6, characterized in that ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The control device, in the searching operation, causes the tips of the plurality of fingers to approach a set of randomly stacked workpieces, and causes the tips of the plurality of fingers to contact any one of the workpieces.

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