CN110961661A

CN110961661A - Mechanical arm

Info

Publication number: CN110961661A
Application number: CN201910874071.7A
Authority: CN
Inventors: 松峯淳平; 木元昭男
Original assignee: Nidec Corp
Current assignee: Nidec Corp
Priority date: 2018-09-28
Filing date: 2019-09-17
Publication date: 2020-04-07
Anticipated expiration: 2039-09-17
Also published as: CN110961661B; JP2020049638A

Abstract

The present invention provides a robot hand for gripping a cylindrical object, the robot hand including: a base portion having a base surface facing the object, the base portion being rotatable about a 1 st rotation axis, the 1 st rotation axis extending in a direction perpendicular to the base surface; a gripping mechanism provided on the base portion and configured to grip the object; a slide detection unit that detects a slide of the object with respect to the gripping unit; and a notification unit configured to notify a detection result of the slip detection unit, wherein the gripping unit includes at least two gripping units configured to grip the object by opening and closing in a direction intersecting the 1 st rotation axis, and the slip detection unit is provided in the gripping unit.

Description

Mechanical arm

Technical Field

The present invention relates to a robot hand.

Background

Conventionally, a screw plate used as a fixing system for a workpiece (object) in an NC processing machine has been difficult to automate the loading and unloading of the workpiece because a special method is used. Therefore, when setting the workpiece with respect to the thread plate, the worker manually attaches the workpiece to the thread plate. Further, the operator visually confirms the seating of the workpiece on the thread plate. In order to significantly improve the work efficiency of workers, robots capable of automating the setting of workpieces have been developed.

With the progress of automation of robots, idling of a workpiece caused after the workpiece is seated on a thread plate has become a problem. That is, if the workpiece rotates idly in accordance with the rotation of the processing machine side while being held by the robot hand, scratches, deformation, and the like may occur on the outer peripheral surface of the workpiece.

Patent document 1 discloses a method for detecting a slip of a workpiece held by a robot using ultrasonic waves. The robot hand grips a workpiece by opening and closing 2 fingers attached to a base, transmits ultrasonic waves from an ultrasonic transducer toward the workpiece, and receives reflected waves from the workpiece to detect sliding of the workpiece. Specifically, the distance between the base and the workpiece is measured based on the time difference between the transmission and reception pulses, and the relative displacement (slippage) of the workpiece is detected based on the difference between the measurement result and the previous measurement result.

Patent document 1: japanese patent laid-open publication No. Sho 58-69652

However, in the case where the workpiece has a cylindrical shape, even if the workpiece rotates, the distance between the base and the workpiece does not change, and therefore it is difficult to accurately detect the relative displacement (sliding) of the workpiece. Therefore, a robot hand capable of accurately detecting a slide after seating even in a cylindrical workpiece is desired.

Disclosure of Invention

In view of the above-described problems, an object of one embodiment of the present invention is to provide a robot hand capable of accurately detecting the sliding of a cylindrical object and automatically supplying a workpiece to a processing machine.

According to the 1 st aspect of the present invention, there is provided a robot for gripping a cylindrical object, the robot including: a base portion having a base surface facing the object, the base portion being rotatable about a 1 st rotation axis, the 1 st rotation axis extending in a direction perpendicular to the base surface; a gripping mechanism provided on the base portion and configured to grip the object; a slide detection unit that detects a slide of the object with respect to the gripping unit; and a notification unit configured to notify a detection result of the slip detection unit, wherein the gripping unit includes at least two gripping units configured to grip the object by opening and closing in a direction intersecting the 1 st rotation axis, and the slip detection unit is provided in the gripping unit.

According to one aspect of the present invention, a robot capable of accurately detecting the sliding of a cylindrical object and automatically feeding the object to a processing machine is provided.

Drawings

Fig. 1 is a perspective view showing a state in which a workpiece is gripped by a robot hand according to an embodiment.

Fig. 2 is a side view showing a state in which a workpiece is gripped by a robot hand according to an embodiment.

Fig. 3 is a front view showing a state in which a workpiece is gripped by a robot hand according to an embodiment.

Fig. 4 is a perspective view showing the structure of a robot according to one embodiment.

Fig. 5 is a diagram for explaining an operation of detecting a slide of a workpiece generated between a robot and the workpiece in a state of being gripped by the robot hand according to one embodiment.

Description of the reference symbols

10. 100, and (2) a step of: a manipulator; 11: a base part; 11 a: a base surface; 11 c: a center; 13: an air chuck gripping mechanism (gripping mechanism); 15: a slide detection mechanism; 19: a telescoping mechanism; 33. 36: a claw portion; 36 a: a claw; 51: a roller; 51 a: the outer peripheral surface of the roller 51; 200 a: the outer peripheral surface of the workpiece 200; 52: a slip detection sensor (notification unit); 53: a detection pin; 131: the 1 st gripping part (gripping part); 132: a 2 nd grip (grip); 200: a workpiece (object); 200 c: an end face of the workpiece 200; d 1: the diameter of the roller 51; d 2: the diameter of the workpiece 200; o1: a central axis (central axis of the base portion 11); o2: the rotation axis (the rotation axis of the roller 51).

Detailed Description

Hereinafter, a rotor and a motor according to embodiments of the present invention will be described with reference to the drawings. The scope of the present invention is not limited to the following embodiments, and may be arbitrarily changed within the scope of the technical idea of the present invention. In the drawings below, in order to facilitate understanding of each structure, the actual structure may be different from the scale, the number, and the like of each structure.

Fig. 1 is a perspective view showing a state in which a workpiece (object) 200 is held by a robot hand 100 according to an embodiment. Fig. 2 is a side view showing a state in which a workpiece 200 is held by the robot hand 100 according to one embodiment. Fig. 3 is a front view showing a state in which the robot hand 100 according to one embodiment grips a workpiece 200. Fig. 4 is a perspective view showing the structure of the robot 100 according to one embodiment. Fig. 5 is a diagram for explaining an operation of detecting a slip occurring between the robot 100 and the workpiece 200 in a state of being held by the robot 100 according to the embodiment.

In the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the X-axis direction is a direction parallel to the axial direction of the central axis O1 and the rotation axis O2 shown in fig. 1. The Z-axis direction is a direction perpendicular to the X-axis direction and is the vertical direction in fig. 1. The Y-axis direction is a direction perpendicular to both the X-axis direction and the Z-axis direction.

Unless otherwise specified, a direction (X-axis direction) parallel to the center axis O1 and the rotation axis O2 is simply referred to as "axial direction", a radial direction around the center axis O1 and the rotation axis O2 is simply referred to as "radial direction", and a circumferential direction around the center axis O1 and the rotation axis O2, that is, a direction around the center axis O1 and the rotation axis O2 is simply referred to as "circumferential direction".

The robot 100 of the present embodiment shown in fig. 1 and 2 is a robot attached to an arm, not shown, and grips a workpiece 200 as an object and supplies the workpiece to a predetermined place. The robot 100 of the present embodiment is used, for example, when feeding or discharging a workpiece 200 to or from an NC processing machine.

The robot 100 is attached to the tip of an arm not shown. The robot hand 100 grips the workpiece 200 in a state where the central axis J of the cylindrical workpiece 200 substantially coincides with the central axis O1 of the robot hand 100.

As shown in fig. 1, 2, 3, and 4, the robot hand 100 includes at least a base portion 11, an air chuck gripping mechanism (gripping mechanism) 13, an expansion/contraction mechanism 19, a slip detection mechanism 15, and a slip detection sensor (notification portion) 52. The operation of the robot 100 is controlled by a control unit (not shown) that drives the arm and the NC processing machine, for example.

The air chuck gripping mechanism 13 in the present embodiment is an example of the "gripping mechanism" of the present invention, and the type of the chuck may be changed as appropriate.

(base part)

The bed portion 11 includes at least: a joint portion 11j (fig. 1 and 4) for connecting to an arm (not shown); and a planar plate member 11k (fig. 3) having a triangular shape. The plate member 11k is provided opposite to the joint portion 11 j. The plate member 11k has a seating surface 11a on the opposite side of the joint portion 11j, and a center 11c (fig. 3) of the seating surface 11a coincides with the central axis O1. The base surface 11a faces one end surface 200c (fig. 2) of the workpiece 200 to be gripped.

(telescoping mechanism)

The telescopic mechanism 19 is provided to the bed portion 11. In the present embodiment, for example, 3 telescopic mechanisms 19 are provided. The telescopic mechanism 19 has a cylindrical shape as a whole, and extends perpendicularly to the base surface 11a along the central axis O1.

As shown in fig. 3 and 4, the telescopic mechanism 19 includes at least a telescopic support portion 41, an elastic portion (not shown), and a telescopic portion 42.

In the present embodiment, the 3 telescopic mechanisms 19 are arranged at equal intervals on a concentric circle centering on the central axis O1. The telescopic mechanisms 19 are disposed at 3 corners of the base surface 11a having a triangular shape, respectively, as viewed in the axial direction shown in fig. 4. The distal end face 42a of each of the expansion/contraction portions 42 of the 3 expansion/contraction mechanisms 19 disposed at each corner portion is disposed at a position capable of contacting an end face 200c (fig. 2) of the workpiece 200 to be gripped.

The telescopic support portion 41 is inserted into and fixed to a through hole 11g provided in the plate member 11 k. The elastic portion disposed inside the telescopic support portion 41 is a member that is capable of expanding and contracting in the axial direction of the central axis O1. As the elastic portion, for example, a spring or the like is used.

The telescopic portion 42 is provided to be movable relative to the telescopic support portion 41 fixed to the plate member 11 k. The expansion/contraction portion 42 is attached to, for example, the tip of the elastic portion, and moves in the axial direction of the central axis O1 (the direction indicated by the arrow a in fig. 4) following the expansion/contraction operation of the elastic portion. The expansion/contraction portion 42 is constantly biased in a direction (+ X side) away from the base surface 11a by an elastic portion that is housed in a contracted state in the expansion/contraction support portion 41. In each of the telescopic mechanisms 19, the urging forces (elastic forces) of the elastic portions acting on the telescopic portion 42 are equal to each other.

In the air chuck, the respective expanding and contracting mechanisms 19 abutting on the end surface 200c of the workpiece 200 are pressed into the end surface 200c of the workpiece 200 in the + X direction by the expanding and contracting portions 42 receiving the urging force of the elastic portions.

(pneumatic chuck holding mechanism)

The air chuck gripping mechanism 13 is provided to the base portion 11. As shown in fig. 3 and 4, the air chuck gripping mechanism 13 includes, for example, 3 gripping portions 31 for gripping the workpiece 200. The number of the grip portions 31 is not limited to 3 as long as there are at least 2 or more grip portions 31. As shown in fig. 3 and 4, the plurality of gripping portions 31 are arranged at equal intervals on a concentric circle centered on the central axis O1, and at least a part of each gripping portion faces the base surface 11a of the plate member 11k in the axial direction.

As shown in fig. 3 and 4, the air chuck gripping mechanism 13 includes one 1 st gripping part (gripping part) 131 and two 2 nd gripping parts (gripping parts) 132. The 1 st gripping part 131 and the 2

nd gripping parts

132 and 132 are simultaneously moved to open and close in a direction perpendicular to the center axis O1 along the base surface 11a when the air chuck is operated.

Here, "opening and closing" of the air chuck gripping mechanism 13 is defined as follows. In the present embodiment, a state in which all the

gripping portions

131, 132 are close to each other toward the center axis O1 is a "closed state: a clamped state "in which the states away from the center axis O1 are set to" open state: the clamped state is released ".

As shown in fig. 3 and 4, the 1 st grip 131 has a 1 st base 32, a 1 st claw 33, and a plurality of screws 34. The 1 st base 32 is formed of a square plate-like member. The 1 st claw portion 33 is formed into an L-shape by cutting or the like. As shown in fig. 4, an opening 33c for arranging a part of the slide detection mechanism 15 is provided in the 1 st part 33A of the 1 st claw part 33, and a plurality of screw holes (not shown) are provided in the 2 nd part 33B of the 1 st claw part 33. The screw 34 for fixing the 1 st claw portion 33 to the 1 st base portion 32 is inserted into each screw hole, and the 1 st claw portion 33 is fixed by being screwed to the 1 st base portion 32 on the one surface 32a side.

As shown in fig. 3 and 4, the 2

nd gripping portions

132, 132 respectively have a 2 nd base portion 35, a 2 nd claw portion 36, and a plurality of screws 34. The 2 nd base 35 is a fan-shaped plate-like member, and a 2 nd claw portion 36 is provided on one surface 35a (a surface on the opposite side of the plate member 11 k) of the 2 nd base 35.

As shown in fig. 4, the 2 nd pawl portion 36 has: a claw 36a extending in the axial direction of the center axis O1; and a fixing portion 36b that expands in a direction perpendicular to the central axis O1 (hereinafter also referred to as a radial direction). The claw 36a has an arc shape when viewed in the axial direction shown in fig. 3, and has a contact surface 36c on the inner side thereof, which contacts the outer peripheral surface 200a of the workpiece 200. The contact surface 36c is a curved surface of about 1/4 perfect circles when viewed from the axial direction, and has a curvature substantially equal to the curvature of the outer peripheral surface 200a of the workpiece 200.

Thereby, substantially the entire contact surface 36c is in contact with the outer peripheral surface 200a of the workpiece 200. If the contact area of each contact surface 36c with respect to the outer peripheral surface 200a of the workpiece 200 in the 2 nd gripping portions 132 is increased, the workpiece 200 can be stably gripped together with the 1 st gripping portion 131.

As shown in fig. 4, the fixing portion 36b is a portion that spreads radially outward in a fan shape from the end of the claw 36 a. The fixing portion 36b has a shape conforming to a part of the outer shape of the 2 nd base portion 35 when viewed from the axial direction.

The 2 nd claw portion 36 is fastened to the one surface 35a side of the 2 nd base portion 35 by a screw 34 inserted into a screw hole (not shown) provided in the fixing portion 36 b.

As shown in fig. 3, when the air chuck gripping mechanism 13 is viewed from the center axis O1, the 1 st gripping part 131 is located on the upper side of the plate member 11k, and the 2

nd gripping parts

132 and 132 are located on the 2 sides 11k2 and 11k2 of the plate member 11k excluding the upper side 11k1, respectively. When the air chuck gripping mechanism 13 is opened and closed, the 1 st gripping part 131 and the 2

nd gripping parts

132 and 132 move in directions (directions indicated by arrows B in fig. 3) intersecting the respective

gripping parts

131, 132 and 132 with respect to the respective sides 11k1, 11k2 and 11k2 of the plate member 11 k.

The air chuck gripping mechanism 13 includes, for example: a cylinder (not shown) for moving the 1 st grip 131; and an interlocking structure (not shown) that transmits the motion of the 1 st gripping part 131 to the 2

nd gripping parts

132, 132. Thus, the 1 st gripping part 131 is moved by driving the air cylinder, and the 2

nd gripping parts

132 and 132 are moved in conjunction with this.

In the air chuck gripping mechanism 13, the force with which the workpiece 200 is gripped can be changed before or after the workpiece 200 is seated on the robot hand 100.

(sliding detection mechanism)

The slide detection mechanism 15 detects the slide of the workpiece 200 with respect to the air chuck gripping mechanism 13. As shown in fig. 3 and 4, the slide detecting mechanism 15 is provided in the 1 st gripping part 131 and moves together with the 1 st gripping part 131.

The slip detection mechanism 15 includes at least a roller 51 and a slip detection sensor 52. As shown in fig. 4, the slide detection mechanism 15 includes a sensor attachment portion 55 and an attachment cover 56.

The roller 51 rotates about the rotation axis O2 shown in fig. 3 and 4. The roller 51 is disposed in the opening 33c (fig. 4) of the 1 st gripping portion 131. The rotation axis O2 of the roller 51 is parallel to the center axis O1 of the robot arm 100.

As shown in fig. 3, when the air chuck gripping mechanism 13 grips the workpiece 200, the roller 51 comes into contact with the outer peripheral surface 200a of the workpiece 200, and supports the workpiece 200 together with the

claws

36a, 36a of the other gripping

portions

132, 132. That is, the roller 51 also functions as a claw of the 1 st gripping portion 131.

The roller 51 can rotate following the rotation of the workpiece 200 in a state where the outer peripheral surface 51a thereof is in contact with the outer peripheral surface 200a of the workpiece 200. As shown in fig. 5, the rotation axis O2 of the roller 51 is parallel to the central axis J of the workpiece 200, and therefore the rotation direction of the workpiece 200 (the direction indicated by the arrow C in fig. 5) and the rotation direction of the roller 51 (the direction indicated by the arrow D in fig. 5) are opposite to each other. Here, the roller 51 is not easily rotated in a state of being in contact with only the workpiece 200.

As shown in FIG. 2, the diameter d1 of roller 51 is smaller than the diameter d2 of workpiece 200. In the present embodiment, the outer periphery of the roller 51 corresponds to, for example, 1/5 of the outer periphery of the workpiece 200.

The roller 51 is preferably made of a material that is less susceptible to the influence of cutting oil used in an NC processing apparatus to which the workpiece 200 is attached, for example. In the present embodiment, Polyacetal (POM) is used.

As shown in fig. 3 and 4, at least one detection pin 53 capable of being detected by the slide detection sensor 52 is provided on the outer circumferential surface 51a of the roller 51. The detection pin 53 has a predetermined length and extends in a direction perpendicular to the rotation axis O2.

The slip detection sensor 52 is, for example, a photoelectric sensor. The slide detection sensor 52 can detect the detection pin 53 by emitting detection light toward the detection pin 53 and receiving reflected light of the detection light. Since the roller 51 having the detection pin 53 follows the rotation of the workpiece 200, the rotation of the roller 51 can be indirectly detected by detecting the detection pin 53.

The slip detection sensor 52 also functions as a notification unit of the present invention, and notifies the control unit of the rotation detection result of the roller 51.

As shown in fig. 4, the slide detection sensor 52 is attached to the 1 st grip 131 via the sensor attachment portion 55. By attaching the slide detection sensor 52 to the sensor attachment portion 55, the slide detection sensor 52 is positioned with respect to the 1 st grip portion 131.

The mounting cover 56 is fixed to the sensor mounting portion 55 so as to surround the periphery of the slide detection sensor 52. By covering the periphery of the slide detection sensor 52 with the attachment cover 56, the detection pin 53 can be detected with high accuracy without being affected by external light. The slide detecting mechanism 15 moves together with the 1 st grip 131.

The control unit that controls the operation of the robot 100 controls the rotation of the screw plate 300 shown in fig. 5 based on the slide information detected by the slide detection mechanism 15.

< actions of manipulator >

Next, the operation of the robot 100 of the present embodiment will be described.

First, 1 of the plurality of workpieces 200 arranged in the tray for conveyance is gripped, and the workpiece 200 is taken out from the tray onto a predetermined base (step 1). The plurality of cylindrical workpieces 200 stored in the tray are arranged with their respective openings facing upward and downward.

In step 1, the control unit moves the arm, for example, to move the robot hand 100 above the workpiece 200 to be gripped. Next, the air cylinder of the air chuck gripping mechanism 13 is driven to move the 3 gripping portions 13 of the air chuck gripping mechanism 13 so as to open. The robot hand 100, which has opened the air chuck gripping mechanism 13, is brought close to the opposed workpiece 200, and the air cylinder is driven again to move the 3 gripping portions 13 so as to close in a state where the 3 telescopic supporting portions 41 provided in the air chuck gripping mechanism 13 are brought close to or brought into contact with the end face 200c of the workpiece 200. At this time, all of the 3 telescopic support portions 41 may not contact the end surface 200c of the workpiece 200.

In this way, 1 target workpiece 200 is gripped and taken out from the tray. Then, the control unit moves the robot hand 100 onto the base, opens the 3 gripping portions 13 of the air chuck gripping mechanism 13 to an open state, and places the workpiece 200 being gripped on the base.

Next, the workpiece 200 taken out of the base is re-gripped by the robot hand 100 again (step 2).

In step 2, the control unit brings all of the 3 expansion/contraction mechanisms 19 into contact with the end surface 200c of the workpiece 200 while keeping the air chuck gripping mechanism 13 in the open state. Each of the telescopic mechanisms 19 presses the workpiece 200 toward the base while contracting in the axial direction of the rotation axis O upon receiving a reaction force from the workpiece 200. Thereby, the end surface 200c of the workpiece 200 is parallel to the base surface 11a of the robot 10. In a state where the 3 telescopic mechanisms 19 are brought into contact with the workpiece 200, the control unit closes the 3 gripping portions 13 of the air chuck gripping mechanism 13 again to be in a closed state, and grips the workpiece 200.

At this time, the outer peripheral surface 51a of the roller 51 of the slide detecting mechanism 15 provided in the 1 st gripping portion 131 is in contact with the outer peripheral surface 200a of the workpiece 200. The workpiece 200 is gripped by the roller 51 of the slide detection mechanism 15 provided in the 1 st gripping part 131 and the

claws

36a, 36a of the other 2

nd gripping parts

132, 132.

Next, the control unit drives the arm to attach the workpiece 200 held by the robot 100 to the screw plate 300 of the NC processing machine (step 3).

In step 3, the control unit moves the robot hand 100 gripping the workpiece 200 so that the workpiece 200 faces the screw plate 300. Then, by rotating the spindle on the machine side, the female screw 200e (fig. 5) provided on the inner side of the workpiece 200 is screwed into the male screw 300e on the screw plate 300 side, whereby the workpiece 200 is mounted on the screw plate 300.

When the workpiece 200 is seated on the thread plate 300, the workpiece 200 does not rotate relative to the thread plate 300. However, since the rotation of the screw plate 300 side is continued after the workpiece 200 is seated, the seated workpiece 200 may run idle in accordance with the rotation of the screw plate 300 in a state of being gripped by the robot hand 100.

Therefore, the control unit monitors the rotation of the roller 51 in the slide detection mechanism 15 during the mounting operation of the workpiece 200 to the screw plate 300 (step 4). The control means preferably starts the detection of the detection pins 53 by the slide detection means 15 at least at the time when the workpiece 200 is gripped by the air chuck gripping means 13. That is, the above-described step 3 and step 4 are simultaneously performed.

In the present embodiment, if the slide detection means 15 detects the detection pin 53 twice, the control means determines that a slide has occurred between the robot 100 and the workpiece 200.

Here, the reason why the detection pins 53 are detected twice is that idling of the workpiece 200 generated between the robot 100 and the workpiece 200 is accurately detected in a state where the workpiece 200 is gripped by the robot 100 after being seated on the screw plate 300. That is, if the detection pin 53 has entered the detection area of the slide detection sensor 52 at the start of detection, the detection pin 53 is detected at a stage where the workpiece 200 is not rotated, and it is also considered that the mounting of the workpiece 200 with respect to the thread plate 300 is not ended.

Therefore, in a state where the workpiece 200 is reliably seated on the screw plate 300 on the machining machine side, it is necessary to detect a slip occurring between the robot 100 and the workpiece 200. Therefore, in the present embodiment, when the detection pin 53 is detected for the second time, it is determined that a slip has occurred between the robot 100 and the workpiece 200.

When the slip detection means 15 detects a slip occurring between the robot 100 and the workpiece 200, the control means performs control based on the detection result. Specifically, when the detection pin 53 is detected twice, the detection result is fed back from the slide detection sensor 52 to the control unit. The control unit stops the rotation of the machine side in accordance with the notification from the slip detection sensor 52. This makes it possible to keep the seated workpiece 200 gripped by the robot hand 100 without being interlocked and rotated following the rotation of the screw plate 300.

As described above, according to the robot hand 100 of the present embodiment, even in the case of the cylindrical workpiece 200 whose outer shape is not easily changed when it is rotated around the axis, it is possible to accurately detect the slide generated between the seated workpiece 200 and the robot hand 100.

Further, by notifying the control unit of the occurrence of a slip between the robot 100 and the workpiece 200 from the slip detection sensor 52, the rotation of the screw plate 300 can be stopped. This makes it possible to quickly stop the sliding between the workpiece 200 seated on the screw plate 300 and the robot hand 100, and prevent the outer peripheral surface 200a of the workpiece 200 from being damaged or deformed. Therefore, the generation of unqualified products can be greatly reduced, and the quality can be stabilized.

Further, conventionally, the work of attaching the workpiece 200 to the screw plate 300 of the NC processing machine is performed by manual work of an operator, but the work of attaching (providing) the workpiece 200 to the screw plate 300 of the NC processing machine can be automated by the robot 100 of the present embodiment, and work efficiency can be improved. Further, since the work (discharging) of detaching the workpiece 200 from the screw plate 300 can be automated, the work efficiency can be further improved.

In addition, in the present embodiment, since the diameter d1 of the roller 51 is smaller than the diameter d2 of the workpiece 200, the above-described slippage can be detected before the workpiece 200 makes one rotation. That is, since the rotation speed of the roller 51 is higher than the rotation speed of the workpiece 200, even a slight slip occurring between the robot 100 and the workpiece 200 can be detected. As a result, the slip occurring between the robot 100 and the workpiece 200 can be detected at an early stage after seating, and a large flaw can be prevented from occurring in the circumferential direction of the workpiece 200 gripped by the robot 100.

In the present embodiment, the number of the detection pins 53 provided to the roller 51 is only 1, but a plurality of detection pins 53 may be provided in the circumferential direction of the roller 51. In the case where the number of the detection pins 53 is only 1 as described above, it is also considered that the detection pins 53 enter the detection area of the slide detection sensor 52 from the beginning, and therefore, in the present embodiment, the slide detection sensor 52 detects 1 detection pin 53 provided twice in the roller 51, thereby detecting the rotation of the workpiece 200. In this case, in order to perform detection twice for 1 detection pin 53, the roller 51 needs to be rotated once.

Therefore, for example, the following method may be adopted: by providing a plurality of detection pins 53 in the circumferential direction on the outer circumferential surface 51a of the roller 51, the second detection pin 53 is detected before the roller 51 rotates once. If this method is adopted, the rotation of the workpiece 200 can be detected at the timing when the two detection pins 53 are detected in the slide detection sensor 52. Therefore, the slide generated between the seated workpiece 200 and the robot 100 can be detected at an earlier stage. This makes it possible to quickly take measures against the slip occurring between the robot 100 and the workpiece 200, and to efficiently prevent the outer peripheral surface 200a from being scratched or deformed.

In addition, conventionally, the seating of the workpiece 200 on the screw plate 300 was confirmed by the visual observation of the operator, but in the robot hand 100 of the present embodiment, the seating of the workpiece 200 on the screw plate 300 can be confirmed mechanically by detecting the rotation of the roller 51 (workpiece 200). The rotation of the roller 51 is started after the workpiece 200 is seated against the thread plate 300. Therefore, by detecting the rotation of the roller 51, the workpiece 200 can be reliably seated on the screw plate 300.

Thus, it is preferable that the sliding of the workpiece 200 with respect to the robot hand 100 is detected as early as possible after the seating of the workpiece 200 is completed, and it is very effective in improving the detection accuracy to provide the plurality of detection pins 53 to the roller 51 as described above.

In addition, the detection accuracy can be improved not only by increasing the number of the detection pins 53 but also by adjusting the ratio of the size of the roller 51 with respect to the workpiece 200.

Further, by providing the slide detection mechanism 15 in the grip portion 31 of the air chuck gripping mechanism 13, space can be saved.

Further, in the robot hand 100 of the present embodiment, since the 3 gripping portions 31 of the air chuck gripping mechanism 13 are opened and closed in the direction intersecting the center axis O1 to grip the workpiece 200 from the radially outer side, the workpiece 200 can be gripped reliably without causing scratches or deformation to the workpiece 200.

Further, by opening and closing the 3 gripping portions 31 in the direction intersecting the center axis O1 to grip the workpiece 200, the workpiece 200 can be gripped with the center thereof being close to the center of the base portion 11. In the present embodiment, by newly grasping the workpiece 200 once gripped, the central axis J of the workpiece 200 can be made to substantially coincide with the central axis O1 of the base portion 11. Thus, for example, the workpiece 200 can be accurately positioned with respect to the screw plate 300 of the NC processing machine, and the supply of the workpiece 200 can be stabilized

In the robot 100 of the present embodiment, the workpiece 200 stored in the conveying pallet is temporarily taken out onto the base as described above, and the workpiece 200 can be gripped in a state where the end surface 200c of the workpiece 200 is parallel to the base surface 11a of the robot 100 by the 3 telescopic mechanisms 19 provided in the base portion 11. By securing the flat surface of the workpiece 200, the female screw on the workpiece 200 side can be smoothly screwed with the male screw 300e on the thread plate 300 side, and thus, for example, the work of mounting the workpiece 200 to the NC processing machine can be reliably and accurately performed.

While the embodiment and the modified examples of the present invention have been described above, the configurations and combinations thereof in the embodiment are only examples, and additions, omissions, substitutions, and other modifications of the configurations can be made without departing from the spirit of the present invention. The present invention is not limited to the embodiments.

The robot 100 of the above-described embodiment is mounted on a machining device such as an NC lathe, for example, but the application of the robot 100 is not particularly limited.

In addition, in the robot 100 of the above-described embodiment, the three-finger air chuck structure is exemplified and described, but the structure for gripping the workpiece 200 is not limited to this.

For example, when the number of the grip portions 31 is only 2, it is preferable that the slide detection mechanism 15 is provided in one grip portion 31 and the other grip portion 31 has a contact surface 36c having a semicircular arc shape when viewed from the axial direction, for example. By adopting such a gripping structure, even if the number of gripping portions 31 is small, the area of contact with the outer peripheral surface 200a of the workpiece 200 can be increased, and therefore the workpiece 200 can be stably gripped.

Further, for example, the following structure may be adopted: the anti-slip member is provided on the contact surface 36c of the 2 nd gripping portion 132 to increase the friction coefficient with the workpiece 200, thereby suppressing the sliding of the seated workpiece 200.

In the above-described embodiment, the detection pin 53 is provided on the outer peripheral surface 51a of the roller 51, but a cam may be provided instead of the detection pin 53.

Claims

1. A manipulator for gripping a cylindrical object, wherein,

the manipulator is provided with:

a base portion having a base surface facing the object, the base portion being rotatable about a 1 st rotation axis, the 1 st rotation axis extending in a direction perpendicular to the base surface;

a gripping mechanism provided on the base portion and configured to grip the object;

a slide detection unit that detects a slide of the object with respect to the gripping unit; and

a notification unit that notifies a detection result of the slip detection mechanism,

the gripping mechanism has at least two gripping portions that grip the object by opening and closing in a direction intersecting the 1 st rotation axis,

the grip portion is provided with the slide detection mechanism.

2. The robot hand of claim 1,

the slide detection mechanism includes:

a roller that is capable of rotating in a state of being in contact with an outer peripheral surface of the object while following sliding of the object; and

and a slip detection sensor that detects rotation of the roller.

3. The robot hand of claim 2,

the axis of rotation of the roller is parallel to the 1 st axis of rotation of the base portion,

the diameter of the roller is smaller than the diameter of the object.

4. The robot hand of claim 2 or 3,

at least one detection pin is provided on the outer peripheral surface of the roller, the detection pin being perpendicular to the rotation axis and being detectable by the slip detection sensor.

5. The robot hand according to any one of claims 1 to 4, wherein,

the manipulator has more than 3 holding parts,

the gripping portions are arranged at predetermined intervals on a concentric circle centered on the 1 st rotation axis.

6. The robot hand according to any one of claims 1 to 5, wherein,

the robot has at least one telescopic mechanism provided in the base portion, and is configured to extend and contract in a direction along the 1 st rotation axis by coming into contact with one end surface of the object in the axial direction, so that the end surface of the object is parallel to the base surface.