JP7354373B1 - Robots and robot systems - Google Patents

Abstract

An object of the present invention is to provide a compact robot hand and robot system in which the actuator of the robot hand is made as small as possible and does not depend on the weight of a conveyed object. A robot system includes a robot arm 40, a robot hand 60 provided at the tip thereof to be rotatable about a first rotation axis 300, and a robot hand 60 provided at a base 62 of the robot hand 60 and provided with a first rotation axis 300. a frame 88 movably provided on the base 62 of the robot hand 60 and movable in a direction orthogonal to the first rotation axis 300; The second finger 72 extends parallel to the axis 300, the first finger 68 is inserted into the first hole of the conveyed object 45, and the second finger 72 is inserted into the second hole, and the robot hand 60 A control device 200 that performs control to rotate the conveyed object 45 by rotating the conveyance object 45 is provided. [Selection diagram] Figure 1

Description

The present invention relates to a robot that moves a conveyed object and rotates its posture, and a robot system using the robot.

Patent Document 1 discloses an invention in which a robot hand has a plurality of fingers and grasps a conveyed object by opening and closing the plurality of fingers using an electric actuator. A robot hand is disclosed in which the opening and closing operations of the fingers of the robot hand are linked. Patent Document 2 discloses an invention of a dual-arm robot relating to an automobile door gripping device and method in an automobile manufacturing process. A first gripping jig and a second gripping jig are provided at the tips of the arms of the dual-arm robot, respectively. The first gripping jig has two door pads, and has a function of varying the distance between the two door pads depending on the type and size of the door to be gripped.

Japanese Patent Application Publication No. 2021-159999 Japanese Patent Application Publication No. 2012-140022

When a robot hand has a plurality of fingers as in Patent Document 1, and these fingers are interlocked by an actuator, when the posture of the fingers grasping the conveyed object changes, the weight of the conveyed object changes depending on the movement of all the fingers. influence In the case of a robot hand with two fingers that open and close, when the two fingers grasp the object and the two fingers are positioned one above the other, the weight of the object acts on the lower finger. A force is applied in the direction of opening the lower fingers. Then, a force in the direction of opening is also applied to the upper fingers, thereby reducing the gripping force. At this time, there is a risk of dropping the transported object. For example, when gripping a heavy object, the risk increases even more. In order to avoid such risks, it is necessary to use a large, highly rigid robot hand or an actuator with large capacity, which increases the structure of the robot hand itself and increases its weight. There was a problem that the carrying weight was small.

In order to solve the problems of the prior art described above, the present invention provides a robot that holds a conveyed object with a robot hand having fingers that are opened and closed by actuators, and rotates the conveyed object. The purpose of the present invention is to provide a robot and a robot system that can minimize the weight and increase the payload.

In order to achieve the above object, the present invention provides a robot that has a plurality of fingers that engage with a conveyed object and moves the conveyed object. a robot hand that is rotatably provided; a first finger that is one of the plurality of fingers and that is provided at the base of the robot hand and extends in a direction parallel to the first rotation axis; and a first finger that is movable to the base of the robot hand. a second finger, one of the plurality of fingers, provided on the frame and extending in a direction parallel to the first axis of rotation; , insert a first finger into a first hole provided in the transferred object, insert a second finger into a second hole provided in the transferred object, and rotate the robot hand around the first rotation axis. A robot system is provided that includes a control device that controls the rotation of the conveyed object by rotating the conveyed object.

According to the present invention, when the conveyed object gripped by the robot hand is rotated about the first finger, the weight of the conveyed object is transferred to the wrist of the robot via the first finger, the second finger, and the frame. receives. In other words, the finger opening/closing servo motor is not subjected to the load in the direction of gravity of the transported object when lifting and turning the transported object. The load supporting capacity of the robot and the rigidity of the wrist, first finger, second finger, and frame need to be large enough to correspond to the weight of the conveyed object to be grasped, but the driving capacity of the finger opening/closing servo motor is All that is required is at least the ability to move the second finger toward and away from the first finger. Therefore, the finger opening/closing servo motor can be made as small as possible, and the robot hand can be made smaller and lighter. In addition, even a small and lightweight robot hand can move heavy objects.

FIG. 1 shows a schematic diagram of a robot according to this embodiment. FIG. 2a is a side view of the robot hand according to this embodiment. FIG. 2b is a front view of the robot hand according to this embodiment. FIG. 2c is a sectional view taken along line AA of the robot hand in FIG. 2a. FIGS. 3(a) to 3(d) are diagrams showing state changes when the robot according to the present embodiment rotates the conveyed object. FIG. 4 is a schematic diagram of a robot system that uses two robots according to the present embodiment to grip and rotate a conveyed object. FIG. 5 is a schematic diagram of a finger rack. FIG. 6 is a schematic diagram of a configuration in which a conveyed object is moved by a robot hand.

Hereinafter, a robot and a robot system according to an embodiment will be described with reference to the accompanying drawings. In order to facilitate understanding, the scale of figures may be changed for explanation.

A robot according to an embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the robot 1 according to the present embodiment includes a swing base 10 installed on the floor, a swing section 20, a first arm 30, a robot arm 40, a wrist section 50, and a robot hand 60. .

The rotating portion 20 is supported by the rotating base 10 so as to be able to rotate around a vertical axis. The first arm 30 is provided so as to be rotatable back and forth on the rotating section 20, and the robot arm 40 is provided so as to be rotatable up and down with respect to the first arm 30. The robot arm 40 has a wrist portion 50 at the tip thereof that is rotatable up and down with respect to the robot arm 40, and further includes a robot hand 60 that is rotatable with respect to the wrist portion 50, and a robot hand 60 that is rotatable with respect to the wrist portion 50. It has a control device 200 that controls 1.

The robot hand 60 includes a base 62, a frame 88, a finger opening/closing servo motor 64, a clamp actuator 66, a first finger 68, a chuck device 70, and a second finger 72.

FIG. 2a shows a side view of a robot hand 60 with two fingers according to the present embodiment, FIG. 2b shows a front view of the robot hand 60 according to the present embodiment, and FIG. 2c shows the A-- A sectional view is shown. In the figure, a wrist portion 50 that is one component of the robot, a robot hand 60 rotatably provided at the tip of the wrist portion 50 around a first rotation axis 300 of the wrist portion 50, and a base 62 are shown. a guide block 82 and a ball screw nut 29 provided in the guide block 82, a rail 84 that engages with the guide block 82, a frame 88 to which the rail 84 is fixed, a finger opening/closing servo motor 64 provided in the frame 88, and a finger opening/closing servo A ball screw 28 coupled to a motor 64, a first finger 68 removably clamped by a clamping actuator 66 provided on a frame 88, and a second finger 72 provided on the frame 88 are shown. In this embodiment, the shank 68a of the first finger 68 has a tapered shape, but is not limited to this, and may have a straight shape, a hexagonal shape, or the like.

A guide block 82 constituting a linear guide device supports a rail 84, and the rail 84 moves back and forth along the axial direction. This embodiment will be described using a ball screw 28, a ball screw nut 29, and a finger opening/closing servo motor 64 as an actuator as a feeding mechanism for moving the frame 88 relative to the base 62. The finger opening/closing servo motor 64 rotates the ball screw 28 and moves the frame 88. By rotating the ball screw 28, the second finger 72 approaches and moves away from the first finger 68.The feeding mechanism is a drive mechanism using a fluid pressure cylinder, and the frame 88 is moved relative to the base 62. may be moved.

The first finger 68 is clamped by a clamp actuator 66 provided on the robot hand 60. The first finger 68 is connected to the wrist portion 50 of the robot 1 via the base 62 of the robot hand 60. When holding the conveyed object 45 , the first finger 68 inserted into the holding hole 47 of the conveyed object 45 preferably has a cylindrical shape and is coaxial with the first rotation axis 300 . Further, the shape of the holding hole 47 is not limited to a circular shape, and various shapes can be considered, but a circular shape is preferable. The second finger 72 is attached to the frame 88 and is preferably a three-claw finger that is expandable and retractable. Note that the position of the holding hole 47 provided in the conveyed object 45 and the interval between the two holding holes 47 are stored in the control device 200, and the positioning of the robot hand 60 and the first The distance between the second finger 68 and the second finger 72 is controlled. The position of the holding hole 47 and the interval between the two holding holes 47 may be stored by teaching the robot in advance, or may be input into the control device 200 as a numerical control program and stored.

FIG. 3 is a flowchart showing state changes when the conveyed object 45 is turned by the robot hand 60, and the procedure will be explained.
In FIG. 3(a), an object 45 is transported in a horizontal position by a cart 100 near the robot. The distance between the first finger 68 and the second finger 72 is adjusted to the distance between the holding holes 47 using the finger opening/closing servo motor 64, and the diameter of the second finger 72 is reduced. Insert finger 72 into holding hole 47. After insertion, the power supply to the finger opening/closing servo motor 64 is turned off. The outer diameter of the first finger 68 is made slightly smaller than the inner diameter of the holding hole 47, and there is a gap between the first finger 68 and the holding hole 47. In FIG. 3(b), the second finger 72 is expanded in diameter and brought into contact with the holding hole 47, and the robot hand 60 is raised to lift the conveyed object 45 in a horizontal position. At this time, the power supply to the finger opening/closing servo motor 64 is kept off so as not to apply a load to the finger opening/closing servo motor 64.

FIG. 3(c) is a diagram showing the rotation of the conveyed object 45 using the first finger 68 as a fulcrum, and as shown in the figure, the conveyed object 45 is lifted by the first finger 68 and the second finger 72. The force is shown as component force divided into the moving direction of the frame 88 and the perpendicular direction. A first component force P11 and a second component force P12 with respect to the lifting force P1 act on the first finger 68. On the other hand, on the second finger 72, a first component force P21 and a second component force P22 with respect to the lifting force P2 act.

In FIG. 3(c), the wrist portion 50 of the robot 1 is rotated to make the conveyed object 45 vertical. When the attitude of the conveyed object 45 is rotated with both fingers 68 and 72 inserted into the holding hole 47, the distance between the first finger 68 and the second finger 72 changes due to the gap. The component force P22 is supported by the first cylindrical finger 68 together with the component force P12. At this time, the component force P21 is supported by the base 62 via the frame 88, the rail 84, and the guide block 82. The component forces P11 and P12 are supported by the base 62 to which the first finger 68 is fixed. By performing such an operation, the weight of the conveyed object 45 is borne only by the base 62. As the attitude of the conveyed object 45 approaches vertical, the gap between the first finger 68 and the second finger 72 gradually increases due to the gap between the first finger 68 and the holding hole 47, but the finger opening/closing servo motor Since the power supply to the finger opening/closing servo motor 64 is turned off, no load is applied to the finger opening/closing servo motor 64. As a result, the component force P22 is not supported by the second finger 72, but is supported by the first finger 68. The moment load due to the component force P21 acting on the second finger 72 is supported by the base 62 via the frame 88. Therefore, during the rotation 49 of the conveyed object 45, only the base 62 bears the weight of the conveyed object 45.

In FIG. 3D, when the object 45 is in a vertical position, the weight of the object 45 is supported only by the first finger 68, and the object 45 is placed on the trolley 100. The second finger 72 is retracted and both fingers are removed from the conveyed object 45. With the above steps, the work of rotating the conveyed object 45 using the robot hand 60 is completed.

For the finger opening/closing servo motor 64 described above, a motor with a torque limiter may be used instead of controlling the power supply of the finger opening/closing servo motor 64 on/off. A motor with a torque limiter is a servo motor with a safety function against overload, and has a clutch that disconnects when a load torque exceeding a preset value is applied to the motor shaft and connects when the load torque returns to the set value. There are motors etc.

As shown in FIG. 4, when two robots are used as a first robot 51 and a second robot 54, they are placed facing each other on both sides of the conveyed object 45, and the robot control device 200 controls the By synchronously controlling the robot 51 and the second robot 54, the conveyed object 45 is rotated in the direction of gravity. The first robot 51 and the second robot 54 each have a first robot hand 52 and a second robot hand 56. If the conveyed object 45 is not large and has a similar length but a thinner thickness, the first robot 51 alone can perform the rotation.
Note that, not limited to this embodiment, when the robot hand performs work such as reversing a workpiece placed on a processing machine or placing a material or a processed workpiece on a trolley, the robot hand may be used to move the material or workpiece in advance. Materials and workpieces can be placed on the trolley after changing their posture.

As shown in FIGS. 5 and 6, the first finger 68 and the second finger 72 can be replaced with a plurality of types of fingers depending on the conveyed object 45 to be held. The first finger 68 is removed, the shank 92 of the replacement finger 110 is inserted into the tapered hole 41 of the finger clamp device 39, and the replacement finger 110 is gripped by the clamping actuator 66 to replace the finger. The second finger 72 is installed by expanding the diameter of the claw of the second finger 72 using the built-in actuator of the chuck device 70, inserting the replacement finger to be replaced, and reducing the diameter of the claw of the second finger 72. grip the shank 90 of.

A finger rack 150 for storing a plurality of types of fingers is provided near the robot. The plurality of types of fingers stored in the finger rack 150 include, in addition to the cylindrical fingers described above, L-shaped fingers that engage with the corners of the conveyed object 45, for example, a first L-shaped finger as shown in FIG. A finger 110 and a second L-shaped finger 120 are provided. Additionally, the shank 92 of the first L-shaped finger 110 has the same tapered shape as the shank of the first finger 68.

In FIG. 6, a first embodiment is shown in which the finger rack 150 shown in FIG. A machine is shown in which a rectangular conveyed object 45 is moved by an L-shaped finger 110 and a second L-shaped finger 120.

Since the robot hand 60 is configured as described above, the capabilities of the ball screw 28 and the finger opening/closing servo motor 64 can be minimized. At least the ability to adjust the distance between the first finger 68 and the second finger 72 under no load is sufficient. In other words, since the actuator for opening and closing the hand can be made smaller, the robot hand 60 can be made smaller and lighter. Then, since the robot hand 60 is lighter, it can hold the heavy conveyed object 45 and perform processing such as turning.

In another embodiment, the camera 400 may be installed on the robot hand 60. If the camera 400 is provided, the robot hand 60 can be photographed by photographing the holding hole 47 without having the control device 200 memorize the position of the holding hole 47 of the conveyed object 45 and the interval between the two holding holes 47 in advance. The relative position of the holding holes 47 with respect to each other and the interval between the two holding holes 47 can be acquired by the control device 200. The distance between the first finger 68 and the second finger 72 may be changed to match the distance between the two holding holes 47 obtained from the photographed results.

1 Robot 39 Finger clamp device 40 Robot arm 45 Object to be transported 50 Wrist portion 51 First robot 54 Second robot 60 Robot hand 62 Base 64 Finger opening/closing servo motor 66 Clamp actuator 68 First finger 72 Second finger 150 Fingerrack 200 Control device 400 Camera

Claims (4)

In a robot system in which a robot hand has a plurality of fingers that engage with a conveyed object and moves the conveyed object,
robot arm and
a robot hand rotatably provided at the tip of the robot arm about a first rotation axis;
a first finger that is one of the plurality of fingers and is provided on the base of the robot hand and extends in a direction parallel to the first rotation axis;
a frame that is movably provided on the base of the robot hand and moves in a direction perpendicular to the first rotation axis;
a second finger that is one of the plurality of fingers and is provided on the frame and extends in a direction parallel to the first rotation axis;
The first finger is inserted into a first hole provided in the conveyed object, the second finger is inserted into a second hole provided in the conveyed object, and the rotation is performed around the first rotation axis. a control device that controls rotating the conveyed object by rotating the robot hand;
Equipped with
The first finger has a cylindrical shape, the axis of the cylinder coincides with the first axis of rotation, and the control device lifts the object with the first axis of rotation in a horizontal state, and lifts the object to be carried by the robot hand. A robot system that rotates . The robot hand includes a base, a frame, a linear guide device that is provided between the base and the frame and guides movement of the frame with respect to the base, and a feed mechanism that moves the frame with respect to the base. The robot system according to claim 1, comprising: The feeding mechanism opens and closes a ball screw provided on the frame along the linear guide device, a ball screw nut provided on the base that engages with the ball screw, and a finger that drives the ball screw. The robot system according to claim 2, comprising a servo motor. Two robots according to claim 1 are used, the robots are arranged on both sides of the conveyed object, and the first fingers of the two robots are inserted into two holes formed on both sides of the conveyed object, respectively. A transfer robot system in which a second finger is inserted, and the control device simultaneously controls the two robots and rotates the transferred object.

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