JP7548733B2 - End effector, robot equipped with same, and holding method - Google Patents

Description

The technology disclosed herein relates to an end effector and a robot equipped with the same.

End effectors that hold a workpiece have been known for some time. For example, Patent Document 1 discloses an end effector that holds a workpiece by suction with a suction part or by clamping with a clamping part.

Patent No. 6667548

Depending on the usage conditions of the end effector, a high degree of positional accuracy may be required for the workpiece being held. In order to improve the positional accuracy of the workpiece, it is conceivable to improve the positional accuracy of the end effector relative to the workpiece when holding it, for example, by using a vision sensor or the like. However, such a method has limitations in the positional accuracy of the workpiece, and there is room for further improvement.

The technology disclosed here has been developed in light of these issues, and its purpose is to improve the positional accuracy of the workpiece held by the end effector.

The end effector disclosed herein includes a holding portion that holds a workpiece and a reference portion that positions the workpiece by contacting the workpiece held by the holding portion.

The robot disclosed herein comprises a first robot arm having a plurality of links rotatably connected to each other, and the end effector connected to the first robot arm.

The end effector can improve the positional accuracy of the workpiece held by the end effector.

The robot can improve the positional accuracy of the workpiece held by the end effector.

FIG. 1 is a plan view of a dual-arm robot. FIG. 2 is a front view of the dual-arm robot. FIG. 3 is a side view of the first end effector. FIG. 4 is a plan view of the first end effector. FIG. 5 is a side view of the second end effector. FIG. 6 is a plan view of the second end effector. FIG. 7 is a block diagram of the control unit. FIG. 8 is a side view showing a state in which the first end effector holds a component. FIG. 9 is a plan view showing a state in which the first end effector holds a component. FIG. 10 is a side view showing a state in which the first end effector has positioned the held part. FIG. 11 is a plan view showing a state in which the part held by the first end effector is positioned.

An exemplary embodiment is described in detail below with reference to the drawings.

The dual-arm robot 100 according to the embodiment will be described. Figure 1 is a plan view of the dual-arm robot 100. Figure 2 is a front view of the dual-arm robot 100.

The dual-arm robot (hereinafter also simply referred to as "robot") 100 comprises a first robot arm 1, a second robot arm 2, and a control unit 6 (see FIG. 7). For example, the robot 100 performs the task of picking up a part P from a parts tray 92 and incorporating the part P into an assembly A. Specifically, the first robot arm 1 picks up the part P from the parts tray 92 and transfers the part P to the second robot arm 2, which then incorporates the part P into the assembly A. The part P is an example of a workpiece.

<Robot arm>
The first robot arm 1 and the second robot arm 2 are multi-joint type robot arms. More specifically, the first robot arm 1 and the second robot arm 2 are horizontal multi-joint type robot arms. The first robot arm 1 and the second robot arm 2 execute operations in cooperation with each other. A first end effector 3 is connected to the first robot arm 1. A second end effector 4 is connected to the second robot arm 2.

For ease of explanation, we will set the X, Y, and Z axes as being perpendicular to each other. The Z axis extends in the vertical direction.

The first robot arm 1 has a first link 11, a second link 12, and a first wrist 13. The second robot arm 2 has a first link 21, a second link 22, and a second wrist 23. The first end effector 3 is connected to the tip of the first robot arm 1, specifically to the first wrist 13. The second end effector 4 is connected to the tip of the second robot arm 2, specifically to the second wrist 23. The first link 11, the second link 12, the first link 21, and the second link 22 are examples of multiple links. Hereinafter, one end of each link in the longitudinal direction is referred to as the first end, and the end opposite the first end in the longitudinal direction is referred to as the second end.

The first end 11a of the first link 11 is connected to a base shaft 111 provided on the upper part of the base 101 via a rotary joint J1. The first link 11 is rotatable around the axis L1 via the rotary joint J1.

The first end 12a of the second link 12 is connected to the second end 11b of the first link 11 via a rotary joint J2. The second link 12 is rotatable around the axis L2 via the rotary joint J2. The first end 12a is disposed below the second end 11b.

The first wrist 13 is connected to the second end 12b of the second link 12 via a linear joint J3. The first wrist 13 is capable of linear motion along the axis L3 via the linear joint J3.

The first end effector 3 is connected to the first end 13a, which is one end of the first wrist 13 in the longitudinal direction, via a rotary joint J4. The first end effector 3 is capable of rotating around the axis L4 via the rotary joint J4.

Axis L1, axis L2, axis L3, and axis L4 extend parallel to one another. In this embodiment, axis L1, axis L2, axis L3, and axis L4 extend in the Z-axis direction, i.e., the vertical direction. In other words, the first link 11, the second link 12, and the first end effector 3 rotate in a horizontal plane, and the first wrist 13 moves linearly in the vertical direction.

The first end 21a of the first link 21 is connected to the base shaft 111 of the base 101 via a rotary joint J5. The first link 21 is rotatable around the axis L1 via the rotary joint J5.

The first end 21a is located below the first end 11a of the first link 11. In other words, the base 101, the first link 21, and the first link 11 are arranged from bottom to top in this order.

The first end 22a of the second link 22 is connected to the second end 21b of the first link 21 via a rotary joint J6. The second link 22 is rotatable around the axis L6 via the rotary joint J6. The first end 22a is located above the second end 21b.

The second wrist 23 is connected to the second end 22b of the second link 22 via a linear joint J7. The second wrist 23 is capable of linear motion along the axis L7 via the linear joint J7.

The second end effector 4 is connected to the first end 23a, which is one end in the longitudinal direction of the second wrist 23, via a rotary joint J8. The second end effector 4 is rotatable around the axis L8 via the rotary joint J8.

Axis L1, axis L6, axis L7, and axis L8 extend parallel to one another. In this embodiment, axis L1, axis L6, axis L7, and axis L8 extend in the Z-axis direction, i.e., the vertical direction. In other words, the first link 21, the second link 22, and the second end effector 4 rotate in a horizontal plane, and the second wrist 23 moves linearly in the vertical direction.

The robot 100 is provided with electric motors 51 (see FIG. 7) that rotate or translate relatively two members connected by each of the joints J1 to J8. For example, the electric motors 51 are servo motors. The robot 100 is also provided with encoders 52 (see FIG. 7) that detect the rotational position of each electric motor.

<End effector>
Fig. 3 is a side view of the first end effector 3. Fig. 4 is a plan view of the first end effector 3.

The first end effector 3 has an adsorption unit 32 that holds the part P, and a reference plate 35. The reference plate 35 positions the part P by contacting the part P held by the adsorption unit 32. The adsorption unit 32 is an example of a holding unit, and the reference plate 35 is an example of a reference unit.

The first end effector 3 may have a first movement mechanism 33 that moves the suction portion 32 relative to the reference plate 35. For example, the first end effector 3 has a base 30 connected to the first wrist 13. The base 30 is connected to the first wrist 13 via a rotary joint J4 so as to be rotatable around an axis L4. The first movement mechanism 33 is provided on the base 30.

The first moving mechanism 33 has a bracket 33a slidably connected to the base 30 in a predetermined first direction, and a first actuator 33b that moves the bracket 33a in the first direction. The first direction extends in a direction perpendicular to the axis L4. For example, the first actuator 33b is an air cylinder. The bracket 33a is provided with an adsorption portion 32.

The first moving mechanism 33 moves the bracket 33a in the first direction, thereby moving the suction part 32 in the first direction accordingly. The first moving mechanism 33 moves the suction part 32 between a first position and a second position in the first direction. The first position is a position in which the suction part 32 is relatively far from the base 30 in the first direction. The second position is a position in which the suction part 32 is closer to the base 30 in the first direction than when it is in the first position.

Although not shown in the figure, a tube is connected to the air cylinder. The tube is connected to an air compressor. The air compressor is housed in the base 101. The air cylinder is operated by air from the air compressor. A solenoid valve is provided on the tube. The solenoid valve switches the air cylinder between advancing and retreating. The air cylinder described below is configured in a similar manner.

The bracket 33a is provided with a second moving mechanism 34 that moves the suction part 32 in a predetermined second direction. The second direction is a direction perpendicular to the first direction and parallel to the axis L4. In this example, the second direction is a vertical direction. For example, the second moving mechanism 34 has a second actuator 34a. For example, the second actuator 34a is an air cylinder. The second actuator 34a has a rod 34b that is configured to be able to move linearly in the second direction. The suction part 32 is provided at the tip of the rod 34b.

The second moving mechanism 34 moves the suction unit 32 between a first position (see solid line in FIG. 3) and a second position (see dashed double-dashed line in FIG. 3) in the second direction. The first position is a position when the suction unit 32 suctions the component P. The second position is a position where the suction unit 32 and the reference plate 35 are aligned in the first direction. The second position is located above the first position. In the first position, the suction unit 32 (specifically, the suction port 32a of the suction unit 32) is located below the reference plate 35.

A suction port 32a that suctions the target object is provided at the lower end of the suction unit 32. Although not shown in the figure, a tube is connected to the suction unit 32. The tube is connected to a vacuum generator. The vacuum generator is housed in the base 101. Negative pressure is generated in the internal space of the suction unit 32 by suction from the vacuum generator. This negative pressure causes the suction unit 32 to suction the target object. A solenoid valve is provided in the tube. The suction unit 32 is switched between suction and release by opening and closing the solenoid valve.

The reference plate 35 has a reference surface 35a that is perpendicular to the first direction. The reference surface 35a faces the suction portion 32 in the first direction. The reference surface 35a is a flat surface.

The first end effector 3 may further include a chuck 36 that clamps the part P in contact with the reference plate 35. The chuck 36 clamps the part P in contact with the reference plate 35. The chuck 36 is an example of a clamping unit.

The chuck 36 is provided on the base 30. The chuck 36 has a pair of fingers 36a connected to the base 30 so as to be slidable in a predetermined third direction, and a third actuator 36b (see FIG. 6) that moves the pair of fingers 36a in the third direction. The third direction is a direction perpendicular to the first direction. In this example, the third direction is also a direction perpendicular to the second direction. The third actuator 36b is, for example, an air cylinder.

The pair of fingers 36a are configured to move closer to or farther away from each other in the third direction. More specifically, the pair of fingers 36a are movable between a first position and a second position in the third direction. The first position is a position where the pair of fingers 36a are relatively far apart from each other. The second position is a position where the pair of fingers 36a are closer to each other than the first position.

The tips of the pair of fingers 36a are positioned closer to the suction portion 32 than the reference plate 35 in the first direction. The position of the tips of the pair of fingers 36a in the second direction is the same as that of the part P held by the suction portion 32 that is positioned in the second position.

Figure 5 is a side view of the second end effector 4. Figure 6 is a plan view of the second end effector 4.

The second end effector 4 has a chuck 41 that grips the part P. For example, the second end effector 4 has a base 40 connected to the second wrist 23. The base 40 is connected to the second wrist 23 via a rotary joint J8 so as to be rotatable around an axis L8. The chuck 41 is provided on the base 40. The chuck 41 is an example of a hand.

The chuck 41 has a pair of fingers 41a connected to the base 40 so as to be slidable in a predetermined fourth direction, and a fourth actuator 41b (see FIG. 6) that moves the pair of fingers 41a in the fourth direction. The pair of fingers 41a are configured to move toward or away from each other in the fourth direction. The fourth actuator 41b is, for example, an air cylinder.

Figure 7 is a block diagram of the control unit 6. The control unit 6 has a calculation unit 61, a memory unit 62, and a servo control unit 63. The calculation unit 61 is formed of a processor such as a CPU. The memory unit 62 is formed of a ROM, a RAM, etc. The servo control unit 63 is formed of a processor such as a CPU.

The memory unit 62 stores information such as a basic program and various data as a robot controller. The calculation unit 61 controls various operations of the robot 100 by reading and executing software such as the basic program stored in the memory unit 62. For example, the calculation unit 61 controls the suction unit 32, the first actuator 33b, the second actuator 34a, the third actuator 36b, and the fourth actuator 41b. Specifically, the calculation unit 61 outputs control signals to the solenoid valve of the tube connected to the suction unit 32 and the solenoid valve of the tube connected to the first actuator 33b.

The servo control unit 63 supplies drive current to each electric motor 51 of the robot 100 and receives detection signals from each encoder 52. For example, the calculation unit 61 generates a control command for the robot 100 and outputs the control command to the servo control unit 63. The servo control unit 63 outputs drive currents to the electric motors 51 corresponding to each of the joints J1 to J8 based on the control command. At this time, the servo control unit 63 controls the drive currents based on the detection signals of each encoder 52.

As shown in FIG. 1, around the robot 100, there are a part placement section 91 on which a part tray 92 containing parts P is placed, and an assembly placement section 93 on which an assembly A is placed. A plurality of parts P are arranged on the part tray 92. One or a plurality of assemblies A are placed in a positioned state on the assembly placement section 93.

The part P has a first edge e1 that serves as a reference for positioning. In addition, the part P may have a second edge e2 and a third edge e3 that serve as references for positioning. For example, the first edge e1, the second edge e2, and the third edge e3 each extend in a substantially straight line. The second edge e2 and the third edge e3 extend parallel to each other and are perpendicular to the first edge e1. The part P further has a fourth edge e4 that extends parallel to the first edge e1, and is generally formed into a substantially rectangular shape in a plan view.

<Robot movement>
Next, the operation of the robot 100 will be described.

The control unit 6 first causes the first end effector 3 to perform a holding operation to hold the part P on the part tray 92. FIG. 8 is a side view showing the first end effector 3 holding the part P. FIG. 9 is a plan view showing the first end effector 3 holding the part P.

In detail, the first robot arm 1 moves the suction portion 32 of the first end effector 3 to the component P to be picked up on the component tray 92. At this time, the first moving mechanism 33 positions the suction portion 32 at the first position. The second moving mechanism 34 positions the suction portion 32 at the first position. The pair of fingers 36a of the chuck 36 are positioned at the first position.

When the suction unit 32 moves to the upper surface of the component P, the suction unit 32 picks up the component P (see the two-dot chain line in FIG. 8). The suction unit 32 picks up the component P with the first edge e1 positioned on the side of the reference plate 35 in the first direction. At this time, the suction unit 32 is positioned at a first position in the first direction and at a first position in the second direction. Therefore, the suction unit 32 is separated from the reference plate 35 in the first direction, and the suction port 32a is positioned below the reference plate 35. As a result, the suction unit 32 can pick up the component P without being affected by (i.e., without being hindered by) the reference plate 35.

Then, as shown by the solid line in FIG. 8, the second moving mechanism 34 moves the suction unit 32 to a second position in the second direction. This causes the component P to be removed from the component tray 92.

Note that at this point, the part P has not been positioned. Therefore, as shown in FIG. 9, a situation may occur in which the first edge e1 of the part P is not parallel to the reference surface 35a of the reference plate 35. The inclination of the first edge e1 relative to the reference surface 35a is also not constant. Furthermore, the position of the part P in the third direction is also not constant.

Next, the control unit 6 causes the first end effector 3 to perform a positioning operation for the held part P. FIG. 10 is a side view showing the state in which the first end effector 3 has positioned the held part P. FIG. 11 is a plan view showing the state in which the first end effector 3 has positioned the held part P.

More specifically, when removal from the part tray 92 is complete, the part P is aligned with the reference plate 35 in the first direction (see the solid line in FIG. 8). In addition, the reference surface 35a of the reference plate 35 and the first edge e1 of the part P face each other.

From that state, as shown in FIG. 10, the first moving mechanism 33 moves the suction portion 32 to a second position in the first direction. That is, the first moving mechanism 33 moves the suction portion 32 toward the reference plate 35 in the first direction by retracting the bracket 33a. As a result, the part P comes into contact with the reference plate 35. More specifically, the first edge e1 of the part P comes into contact with the reference surface 35a of the reference plate 35. This determines the position of the part P in the first direction.

At this time, the suction unit 32 is suspended from the second moving mechanism 34 via the rod 34b that extends in a cantilever shape, and is therefore able to move slightly. Therefore, as shown in FIG. 11, the part P is positioned so that the first edge e1 and the reference surface 35a are in line contact with each other.

Specifically, the position of the part P in the first direction is determined to be the position where the first edge e1 contacts the reference surface 35a. In addition, the angular position of the part P around an axis extending in the second direction, i.e., the posture, is determined to be a state in which the first edge e1 and the reference surface 35a are parallel.

From this state, the chuck 36 clamps the part P from the third direction. More specifically, one finger 36a contacts the second edge e2 of the part P, and the other finger 36b contacts the third edge e3 of the part P. This determines the position of the part P in the third direction.

Next, the control unit 6 causes the first end effector 3 and the second end effector 4 to execute the part P transfer operation.

In detail, the first robot arm 1 transports the part P positioned by the first end effector 3 to a predetermined transfer location. At this time, the first end effector 3 maintains the part P in contact with the reference plate 35. The second robot arm 2 moves the second end effector 4 to the transfer location. At the transfer location, the second end effector 4 grips the part P held by the first end effector 3 with the chuck 41. Specifically, the chuck 41 grips the second edge e2 and the third edge e3 of the part P. After the chuck 41 grips the part P, the suction portion 32 of the first end effector 3 releases the suction of the part P and the chuck 36 releases the clamping of the part P. As a result, the part P is transferred from the first end effector 3 to the second end effector 4.

Then, the control unit 6 causes the second end effector 4 to perform the operation of assembling the part P into the assembly A.

In more detail, the second robot arm 2 transports the part P held by the chuck 41 to the assembly A and places it in a predetermined location in the assembly A. The chuck 41 then releases its grip on the part P. This completes the incorporation of the part P into the assembly A.

In this way, the first end effector 3 holds the part P in a positioned state, thereby improving the positional accuracy when the part P is incorporated into the assembly A. In other words, because the first end effector 3 holds the part P with high positional accuracy, the second end effector 4 that receives the part P from the first end effector 3 also grasps the part P with high positional accuracy. Therefore, the positional accuracy of the part P is improved when the second end effector 4 incorporates the part P into the assembly A. As a result, the positional accuracy when the part P is incorporated into the assembly A is improved.

More specifically, the positional accuracy of the components P arranged on the component tray 92 may not be very high. Also, the accuracy of the suction position when the suction unit 32 suctions the component P may not be very high. For example, when the suction unit 32 suctions the top surface of the component P, the positional accuracy of the suction unit 32 in a plane parallel to the top surface of the component P is not very high. In addition, because the suction unit 32 is supported in a suspended state, it may be subject to some displacement. For this reason, the positional accuracy of the suction unit 32 in a plane parallel to the top surface of the component P is not very high.

Furthermore, in a configuration in which the part P is held by hanging, the positional accuracy of the part P when it is handed over from the first end effector 3 to the second end effector 4 may not be very high. For example, when the transportation of the part P to the delivery location to the second end effector 4 is completed, the part P may sway due to inertia during transportation. If the second end effector 4 receives the part P while it is still swaying, the positional accuracy of the part P at the second end effector 4 decreases. On the other hand, if the delivery of the part P is delayed until the swinging of the part P stops, the delivery time of the part P will be longer. Furthermore, when the second end effector 4 holds the part P, the second end effector 4 may come into contact with the part P, causing the part P to be displaced.

The first end effector 3 holds the part P in a positioned state, thereby improving the positional accuracy of the part P as described above. In other words, the first end effector 3 holds the part P in a state of contact with the reference plate 35, thereby improving the positional accuracy of the part P held by the first end effector 3. Furthermore, since the part P is maintained in contact with the reference plate 35 even when the part P is transported by the first end effector 3, displacement such as swinging of the part P is reduced. Furthermore, since the part P is maintained in contact with the reference plate 35 even when the part P is transferred from the first end effector 3 to the second end effector 4, the positional accuracy of the part P when the part P is transferred is also improved.

As described above, the first end effector 3 includes an adsorption portion 32 (holding portion) that holds a part P (workpiece), and a reference plate 35 (reference portion) that positions the part P by contacting the part P held by the adsorption portion 32.

With this configuration, the first end effector 3 can hold the part P in a positioned state by holding the part P in contact with the reference plate 35. This improves the positional accuracy of the held part P.

The device further includes a first moving mechanism 33 that moves one of the suction unit 32 and the reference plate 35 relative to the other, and the first moving mechanism 33 moves one of the suction unit 32 and the reference plate 35 relative to the other while the suction unit 32 holds the part P, thereby bringing the part P into contact with the reference plate 35.

According to this configuration, after the suction unit 32 holds the component P, the component P can be brought into contact with the reference plate 35. In other words, when the suction unit 32 holds the component P, the component P is not in contact with the reference plate 35. If the reference plate 35 and the component P, i.e., the suction unit 32, are close to each other when the suction unit 32 holds the component P, there is a risk that the reference plate 35 will interfere with the suction unit 32's holding operation of the component P. By keeping the reference plate 35 and the suction unit 32 apart when the suction unit 32 holds the component P, the suction unit 32 can hold the component P without being affected by the reference plate 35.

The first end effector 3 further includes a second moving mechanism 34 that moves either the suction unit 32 or the reference plate 35 in the movement direction of the first moving mechanism 33 to a position where the reference plate 35 and the part P held by the suction unit 32 are aligned.

According to this configuration, after the suction unit 32 holds the part P, the second moving mechanism 34 can bring the reference plate 35 and the part P into a state where they are aligned in the movement direction of the first moving mechanism 33. From this state, the first moving mechanism 33 brings the part P into contact with the reference plate 35. In other words, when the suction unit 32 holds the part P, the part P is not in contact with the reference plate 35, and the reference plate 35 and the part P are not aligned in the movement direction of the first moving mechanism 33. During the holding operation of the part P by the suction unit 32, the reference plate 35 and the suction unit 32 can be further separated.

The first end effector 3 also includes a chuck 36 (clamping portion) that clamps the part P in contact with the reference plate 35.

According to this configuration, the part P is positioned by the chuck 36 in addition to the reference plate 35. That is, the part P is positioned relative to the reference plate 35 by contacting the part P with the reference plate 35. In addition, the part P is clamped by the chuck 36, so that the part P is positioned relative to the chuck 36 in the clamping direction of the chuck 36. This further improves the positional accuracy of the part P.

The robot 100 includes a first robot arm 1 having a first link 11 and a first link 12 (multiple links) rotatably connected to each other, and a first end effector 3 connected to the first robot arm 1.

According to this configuration, the first robot arm 1 moves the first end effector 3. The first end effector 3 maintains the part P in contact with the reference plate 35 even during movement, thereby improving the positional accuracy of the part P during and after the movement of the first end effector 3.

The robot 100 further includes a second robot arm 2 having a first link 21 and a second link 22 (multiple links) rotatably connected to each other, and a chuck 41 (hand) connected to the second robot arm 2, and the chuck 41 receives the part P held by the suction portion 32 and positioned by the reference plate 35 from the first end effector 3.

With this configuration, the chuck 41 can receive the part P that has been positioned by the first end effector 3. As a result, the chuck 41 can hold the part P with high positional accuracy. Furthermore, the chuck 41 can also achieve high positional accuracy for the part P in subsequent operations.

Other Embodiments
As described above, the above embodiment has been described as an example of the technology disclosed in this application. However, the technology in this disclosure is not limited to this, and can be applied to embodiments in which modifications, replacements, additions, omissions, etc. are appropriately performed. In addition, it is also possible to combine the components described in the above embodiment to form a new embodiment. In addition, among the components described in the attached drawings and detailed description, not only components essential for solving the problem but also components that are not essential for solving the problem in order to exemplify the technology may be included. Therefore, the fact that these non-essential components are described in the attached drawings and detailed description should not immediately be taken to mean that these non-essential components are essential.

For example, the robot 100 includes a first robot arm 1 and a second robot arm 2, but is not limited to this. For example, the robot 100 may include the first robot arm 1 but not the second robot arm 2. In other words, the first end effector 3 may not transfer the held part P to the second end effector 4 of the second robot arm 2. For example, the first end effector 3 may place the held part P in a predetermined location. Also, the robot 100 may not be a dual-arm robot. For example, the first robot arm 1 and the second robot arm 2 may be provided on separate bases.

The workpiece held by the first end effector 3 is not limited to the part P. The first end effector 3 can hold a variety of workpieces. In this case, the first end effector 3 can position the workpiece relative to a reference portion by bringing a part of the held workpiece into contact with a reference portion such as the reference plate 35.

The holding part is not limited to the suction part 32. The holding part may have any configuration as long as it is capable of holding the workpiece. For example, the holding part may be a chuck that clamps the workpiece. In addition, the number of suction parts 32 is not limited to one, and may be multiple.

The reference portion is not limited to the reference plate 35. The reference portion may have any configuration as long as it can contact the workpiece to position the workpiece. For example, the reference portion may be a block.

In addition, the portion of the workpiece that comes into contact with the reference portion is not limited to an edge. The portion of the reference portion that comes into contact with the workpiece is not limited to a surface. For example, the workpiece and the reference portion may be in contact at one or more points. The contact may be surface contact, line contact, or point contact.

The first moving mechanism 33 moves the suction portion 32, i.e., the holding portion, toward the reference plate 35, i.e., the reference portion, but is not limited to this. For example, the first moving mechanism 33 may bring the workpiece and the reference portion into contact with each other by moving the reference portion toward the holding portion.

The second moving mechanism 34 moves the suction portion 32, i.e., the holding portion, but is not limited to this. The second moving mechanism 34 may move the reference plate 35, i.e., the reference portion, so that the reference portion and the workpiece held by the holding portion are aligned in the movement direction of the first moving mechanism.

The clamping section is not limited to the chuck 36. The clamping section may be configured to clamp the workpiece between an immovable member and a movable member. For example, one of the pair of fingers 36a of the chuck 36 may be immovable, and the other finger 36a may be movable in the third direction. In this case, the workpiece is pressed against the immovable finger 36a by the movable finger 36a. This determines the position of the workpiece in the third direction.

The direction in which the clamping unit clamps the workpiece is not limited to the third direction. The clamping unit has the function of positioning the workpiece, which has been positioned in the first direction by the reference unit, in a direction different from the first direction. Therefore, the direction in which the clamping unit clamps the workpiece can be set to any direction different from the first direction.

1 First robot arm 11 First link 12 Second link 2 Second robot arm 21 First link 22 Second link 3 First end effector 32 Adsorption portion (holding portion)
33 First moving mechanism 34 Second moving mechanism 35 Reference plate (reference portion)
36 Chuck (clamping part)
41 Chuck (hand)
100 Dual-arm robot (robot)
P Part (work)

Claims (5)

An end effector coupled to a robot arm,
A holding part for holding a workpiece;
a reference portion that positions the workpiece by contacting the workpiece held by the holding portion ;
a first moving mechanism that moves one of the holding portion and the reference portion relative to the other in a predetermined first direction;
a clamping portion that clamps the workpiece in a state in contact with the reference portion ,
the first moving mechanism moves one of the holding portion and the reference portion relative to the other while the holding portion holds the workpiece, thereby bringing the workpiece into contact with the reference portion on only one side in the first direction;
The clamping portion is an end effector that clamps the workpiece from a direction different from the first direction . The end effector of claim 1 ,
The end effector further includes a second moving mechanism that moves either the holding portion or the reference portion to a position where the reference portion and the workpiece held by the holding portion are aligned in the movement direction of the first moving mechanism. a first robot arm having a plurality of links rotatably connected to one another;
A robot comprising: an end effector according to claim 1 or 2 coupled to the first robot arm. The robot according to claim 3 ,
a second robot arm having a plurality of links rotatably connected to each other;
a hand coupled to the second robot arm,
The hand is a robot that receives the workpiece held by the holding portion and positioned by the reference portion from the end effector. A holding method for holding a workpiece by an end effector connected to a robot arm, the method comprising: a holding unit for holding a workpiece; a reference unit for contacting the workpiece to position the workpiece; a first moving mechanism for moving one of the holding unit and the reference unit relative to the other; and a clamping unit for clamping the workpiece, the method comprising:
Holding a workpiece by the holding portion;
With the holding unit holding the workpiece, the first moving mechanism moves one of the holding unit and the reference unit relative to the other in a predetermined first direction to bring the workpiece into contact with the reference unit on only one side of the first direction, thereby positioning the workpiece.
A holding method including: clamping the workpiece in contact with the reference portion from a direction different from the first direction by the clamping portion.

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