JP2008207263A - Robot hand - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive robot hand having a simple configuration and reliably handling and holding even workpieces of different shapes. <P>SOLUTION: This robot hand is provided with: a plurality of finger parts 2 extended from a tip of an arm part 1 of a robot, sucker parts 3 arranged in each finger part 2; and a revolute joint part 5 for connecting the arm part 1 of the robot with the finger parts 2 to change an angle freely. Each sucker part 3 is provided to change its attitude freely. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a robot hand that can hold a workpiece.

  Conventionally, as a robot hand for holding a workpiece and performing assembly work or the like, as disclosed in Patent Document 1, for example, a suction pad has been provided at the tip of a robot arm, and the suction pad is pressed to perform air suction. The thing of the structure which adsorb | sucks a workpiece | work is known. However, there is a problem in that it is difficult to reliably hold a workpiece that is not a specific workpiece having a predetermined shape if the configuration simply includes the suction pad.

On the other hand, for example, as disclosed in Patent Document 2, a robot having a plurality of fingers such as a human hand and holding the workpiece by sandwiching the workpiece with the plurality of fingers. The hand is also known. If the robot hand having such a structure is used, it can be reliably gripped corresponding to workpieces of various shapes. However, the robot hand has a problem in that it is difficult to provide at low cost because of its complicated structure and control.
JP2003-165081 JP 2006-346792

  The present invention has been invented in view of the above-mentioned problems, and it is an object to provide a robot hand capable of reliably holding a workpiece having various shapes with a simple configuration at a low cost. To do.

  In order to solve the above-described problems, the present invention includes a plurality of finger portions 2 extending from the tip of the robot arm portion 1 and suction cups 3 disposed on the respective finger portions 2. The robot hand is characterized in that it can be freely changed in posture. By doing in this way, it is possible to reliably hold a plurality of sucker portions 3 whose postures can be changed even for workpieces of various shapes as well as workpieces of a specific shape having a large flat surface. it can. In addition, the structure and control are simple and can be provided at low cost.

  In the robot hand having the above-described configuration, it is preferable that the robot arm portion 1 and each finger portion 2 are provided with a joint portion 5 that connects the angle portions so that the angle can be changed. By doing in this way, each finger | toe part 2 can each hold | maintain a workpiece | work, changing an angle, Furthermore, it becomes possible to respond also to a workpiece | work of various shapes.

  Further, the finger part 2 is formed by a plurality of phalanx parts 9a, 9b,... And joint parts 10 that connect adjacent phalange parts 9a, 9b,. , 9b,... Is also preferably arranged. By doing in this way, each finger | toe part 2 bends correspondingly also with respect to the workpiece | work from which a magnitude | size and a shape differ, and a workpiece | work can be reliably hold | maintained by many suction cup parts 3. FIG.

  It is also preferable to provide an angle detector installed at the joint portions 5 and 10. By doing so, it is possible to estimate the positional relationship between the workpiece to be held and the robot hand based on the detected angle information, thereby enabling precise assembly work.

  It is also preferable to provide an angle changing actuator installed in the joint portions 5 and 10. By doing in this way, the angle of each joint part 5 and 10 can be changed arbitrarily, and delicate position control is attained, Therefore Precise assembly work is attained.

  Here, it is preferable that the angle changing actuator includes the ultrasonic motor 11 and the shape memory alloy 12. When the ultrasonic motor 11 is used, it is possible to reduce the size and weight by generating a large torque with respect to its dimensions. When the shape memory alloy 12 is used, the suction cup portion 3 is elastic to the workpiece. It is possible to guess.

  Further, in the robot hand having the above-described configuration, the central suction cup 13 disposed at the center of the tip of the robot arm 1 and the driver bit 15 that is detachably attached to the central suction cup 13 and has a driver 15b at the tip. It is also suitable to have. By doing in this way, the operation | work which hold | maintains workpiece | works, such as an assembly operation | work, and the fastening operation | work performed using a driver are realizable with one robot hand.

  As a means for rotating the driver bit 15, the robot arm 1 side may be provided with a rotation motor that integrally rotates the driver bit 15 so that the driver 15 b at the tip rotates about the axis. It is preferable that the rotary motor 18 that rotates the driver 15b at the tip end about the axis is provided on the 15 side. For example, since many horizontal articulated robot arm portions 1 are rotatable about the axis, the configuration using the rotary motor on the robot arm portion 1 side in this way allows the driver without adding a special configuration. The bit 15 can be rotated. Further, if the configuration is provided with the rotary motor 18 on the driver bit 15 side, the robot arm unit 1 that cannot rotate about the axis can be applied.

  It is also preferable to include a drop detection means for detecting that the screw 16 has dropped from the driver bit 15. By doing in this way, even when the screw 16 held by the driver 15b at the tip end due to a magnetic attraction force or the like is dropped during transportation or the like, this can be quickly detected and dealt with.

  Each configuration described above can be appropriately combined without departing from the gist of the present invention.

  The present invention has an effect that it is possible to provide a robot hand that can reliably hold workpieces having various shapes with a simple configuration at a low cost.

  Hereinafter, the present invention will be described based on embodiments shown in the accompanying drawings. FIG. 1 shows a robot hand of a first example in the embodiment of the present invention. As shown in the figure, the robot hand of this example has a pair of finger portions 2 that extend symmetrically from the tip of the robot arm 1 whose position and posture can be controlled, and one finger portion 2 at the tip of each finger portion 2. A suction cup 3 connected to each suction cup 3 and a hose 4 for sucking air in the suction cup 3 and a pump (not shown) connected to each hose 4 to generate suction force. is doing.

  The pair of finger portions 2 are integrally formed in a straight line, and the angle can be changed with respect to the robot arm portion 1 through the joint portion 5. In other words, a rod-shaped support member 6 is formed by the pair of finger portions 2, and the robot arm portion 1 is rotatably connected to the center of the support member 6 via the joint portion 5. In this structure, suction cups 3 are provided at both ends of the direction.

  Each sucker portion 3 is installed on each finger portion 2 so as to face the same direction (downward in the illustrated example), and three-dimensionally within a predetermined range centered on the same direction by way of the ball joint 7. It is freely rotatable. In addition, the installation location of the suction cup part 3 is not limited to the front-end | tip part of each finger part 2, What is necessary is just to install at least 1 each in the location from the front-end | tip part of each finger | toe part 2 to a center part. Further, the number of finger portions 2 is not limited to two, and three or more finger portions 2 may be provided.

  In this example, the suction cups 3 can be independently changed in posture through the ball joints 7 as described above, so that any shape having no flat surface as shown in FIG. Even when holding the workpiece W, the robot arm portion 1 is driven to bring the suction cup portion 3 close to the outer surface of the workpiece W, and air is sucked from the suction cup portion 3 through the hose 4, thereby The suction cup 3 is attracted to the outer surface of the workpiece W while changing the posture, and holds the workpiece W securely.

  Next, the robot hand of the second example in the embodiment of the present invention will be described with reference to FIG. 2, but detailed description of the same configuration as the first example described above will be omitted. In the robot hand of this example, the pair of finger parts 2 are not integrally formed, but each finger part 2 is independently rotatably connected to the robot arm part 1 via the joint part 5. Moreover, in this example, the ball joint 7 as an example is not provided, and each suction cup part 3 is fixed to the finger part 2 in the same direction (downward in the illustrated example).

  Each finger part 2 is fixed to the sucker part 3 of each finger part 2 from an initial posture (see FIG. 2A) extending in the opposite direction so that the pair of finger parts 2 form a straight line. It can be rotated within a range up to a substantially square holding posture (see FIG. 2B) with the sides close to each other. The finger part 2 is provided with a spring member 8 for applying an urging force for returning both the finger parts 2 to the initial posture, so that the suction cups 3 are in an initial posture that is most separated from each other in the absence of a load. Provided. In other words, in this example, the pair of fingers 2 form a rod-like support member 6 that can be refracted from an initial posture that is in a straight line shape to a holding posture that is substantially U-shaped. The suction member 3 is fixed to the surfaces of the support members 6 that are close to each other during refraction at both end portions in the axial direction of the support member 6. In addition, you may interpose the ball joint 7 between each finger | toe part 2 and the suction cup part 3 further.

  Thus, in this example, each finger part 2 and each sucker part 3 can change posture independently through the joint part 5. Therefore, even when holding an arbitrarily shaped workpiece W that does not have a flat surface as shown in FIG. 2B, the robot arm 1 is driven to bring the suction cup 3 closer to the outer surface of the workpiece W. By sucking air from the suction cup part 3 through the hose 4, each finger part 2 and each suction cup part 3 fixed to the tip of each finger are adsorbed to the outer surface of the work W while changing the posture, It holds securely from both sides.

  Next, the robot hand of the third example according to the embodiment of the present invention will be described with reference to FIG. 3, but detailed description of the same configuration as that of the second example described above will be omitted. Each finger part 2 of the robot hand of this example is formed by connecting a pair of phalange parts 9a and 9b via the joint part 10 so that the angle can be changed. Each finger segment 9a, 9b has a suction cup portion 3 fixed to the tip thereof and an air suction hose 4 connected thereto, so that air is sucked from the four suction cup portions 3 for convenience. Yes.

  As shown in FIG. 3A, in the initial posture, each finger portion 2 refracts the distal phalange portion 9a toward the robot arm portion 1 side to stand by. Only the part 9b is used like the finger part 2 of the second example to hold the workpiece W. Then, when holding a large workpiece W that is difficult to grasp with only the root side phalanx portion 9b, the distal side phalanx portion 9a is used together with the root side phalanx portion 9b as shown in FIG. 3B. To do.

  The joint portion 10 between the phalanx portions 9a and 9b is internally provided with a pneumatic rotary cylinder (not shown) that forms an angle changing actuator, and when the distal phalange portion 9a is used. Then, air is sucked from the hose 4 of the phalanx part 9a to interlock the rotation cylinder of the joint part 10 and rotate the phalanx part 9a toward the workpiece W side. Then, the suction cups 3 at the four positions are brought close to the outer surface of the work W and the air suction is continued, so that each sucker part 3 is attracted to the outer surface of the work W in an appropriate posture, and the work W is surely secured. Hold.

  Each joint 5, 10 is provided with an angle detector (not shown) composed of a rotary encoder, and is detected from the angle detector in a state where the workpiece W is gripped as shown in FIG. The positional relationship between each finger part 2 of the robot hand and the work W is estimated based on the angle information to be entered and the length information of the phalange parts 9a and 9b and the shape information of the work W inputted in advance. As a result, the positional relationship between the robot arm 1 and the workpiece W is estimated, and assembly work performed by holding the workpiece W on the robot hand becomes precise.

  In this example, one finger 2 is formed by a pair of finger segments 9a, 9b, but one finger 2 is formed by three or more finger segments 9a, 9b,. It may be formed. Even in this case, the suction cup portion 3 and the hose 4 are connected to the respective finger joint portions 9a, 9b,... To make the air suckable, and similar to the joint portion 10 that connects the finger joint portions 9a, 9b,. By arranging this actuator, it is possible to securely hold the workpiece W while flexibly responding to the shape and dimensions of the workpiece W.

  Next, a robot hand of a fourth example in the embodiment of the present invention will be described with reference to FIG. 4, but detailed description of the same configuration as that of the third example described above will be omitted. Each joint 5 and 10 of the robot hand of this example is equipped with an ultrasonic motor 11 as an angle changing actuator. By driving each ultrasonic motor 11, the angles of the corresponding joint portions 5 and 10 can be freely changed. The ultrasonic motor 11 does not need to be equipped with a gear in order to generate a large torque compared to the size thereof, and a reduction in size and weight is realized.

  When gripping the workpiece W, first, the ultrasonic motor 11 of the joint portion 5 is driven to set the angle according to the workpiece W, and then the joint portion 10 of each finger portion 2 is driven to easily grip the workpiece W. Move to position. Then, by causing the suction cups 3 of the finger segments 9a and 9b to perform air suction, the workpieces W having various shapes and dimensions as shown in FIG. 4B can be reliably held.

  Each ultrasonic motor 11 is provided with an angle detector (not shown) composed of a rotary encoder. Thus, the positional relationship between each finger 2 of the robot hand and the workpiece W and the positional relationship between the bot arm 1 and the workpiece W are estimated as in the third example.

  The actuator composed of the ultrasonic motor 11 may be provided only in the joint portion 10 between the phalanx portions 9a and 9b. In this case, the joint 5 between the root side phalanx 9b and the robot arm 1 is provided with a return spring member 8 similar to the second and third examples, and the work W of the suction cup 3 is provided. What is necessary is just to provide so that it may resist against the urging | biasing force of the spring member 8 with the attractive force with respect to.

  Next, the robot hand of the fifth example according to the embodiment of the present invention will be described with reference to FIG. 5, but detailed description of the same configuration as the third example will be omitted. Each joint portion 5 and 10 of the robot hand of this example is equipped with a shape memory alloy 12 provided in a helical spring shape as an angle changing actuator. The shape memory alloy 12 has a structure that contracts due to heat generation when an electric current is passed. By operating each shape memory alloy 12, the angle of the corresponding joint portions 5 and 10 can be freely changed. According to such an actuator using the shape memory alloy 12, the structure becomes simple and the sucker portion 3 of each finger portion 2 can be elastically pressed against the workpiece W. In addition, the joint portions 5 and 10 are provided with a return spring member 8 so as to maintain the initial posture of FIG. 5A when the shape memory alloy 12 is not operated.

  When gripping the workpiece W, first, an electric current is applied to the shape memory alloy 12 of the joint portion 5 to contract by an appropriate amount, and the joint portion 5 is set to an angle according to the workpiece W. Next, a current is passed through the shape memory alloy 12 of the joint 10 of each finger 2 to rotate the joint 10 and move the workpiece W to a position where it can be easily grasped. Then, by causing the suction cups 3 of the finger segments 9a and 9b to perform air suction, the workpieces W having various shapes and dimensions as shown in FIG. 5B can be reliably held.

  Each joint 5 and 10 is provided with an angle detector (not shown) formed of a rotary encoder. Thereby, the positional relationship between each finger 2 of the robot hand and the workpiece W and the positional relationship between the robot arm 1 and the workpiece W are estimated as in the third example.

  The actuator made of the shape memory alloy 12 may be provided only in the joint portion 10 between the finger joint portions 9a and 9b. In this case, the joint portion 5 between the root side phalanx portion 9b and the robot arm portion 1 is provided so as to rotate against the biasing force of the spring member 8 by the suction force of the suction cup portion 3 to the work W.

  Next, a robot hand of a sixth example according to the embodiment of the present invention will be described with reference to FIG. 6, but detailed description of the same configuration as that of the first example described above will be omitted. As shown in FIG. 6A, in the robot hand of this example, a central sucker portion 13 is arranged at a location that is the center of the tip of the robot arm portion 1 (that is, a location through which the central axis A of the robot arm portion 1 passes). The air can be sucked from the central suction cup 13 through the hose 14. And in this example, the driver bit 15 which attaches | detaches to said center suction cup part 13 detachably is provided. The driver bit 15 is mainly composed of a flat plate attaching / detaching portion 15a having a flat surface for suction and a driver 15b extending in a direction orthogonal to the flat surface of the attaching / detaching portion 15a.

  A motor (not shown) for rotating the robot arm 1 around the central axis A is provided on the robot arm 1 side, and a driver bit 15 is attached to and detached from the central suction cup 13 of the robot arm 1. The driver bit 15 is rotated integrally with the robot arm 1 by adsorbing the flat surface of the portion 15a and driving the motor on the robot arm 1 side. The driver bit 15 is adsorbed at a position where the central axis of the driver 15b coincides with the stop of the robot arm 1 and the axis A coincides so that the driver 15b at the tip rotates about the axis.

  By providing the central suction cup 13 and the driver bit 15 as described above, when the screw 16 is fastened, the driver bit 15 is attached, the work is held, the work W is held, and the assembly work is performed. In this case, it is possible to perform various operations using one robot hand, such as removing the driver bit 15 and sucking the workpiece W using another sucker unit 3. Of course, the same effect can be obtained by applying the same configuration to the robot hands of the second to fifth examples.

  In addition, the driver bit 15 of this example includes a strain cage 17 as a drop detection means for detecting that the screw 16 has dropped from the driver 15b on the tip side. The screw 16 is held by the driver 15b by a magnetic attraction force. The weight of the screw 16 is detected by a strain cage 17 attached to the driver 15b. You can know the dropout. The drop-off detection means is not limited to the strain cage 17 and may be other means using a metal detection sensor, an image processing apparatus, or the like.

  FIG. 6B shows a further modification of this example. As shown in the figure, the driver bit of this example is applied to a robot hand in which the central suction cup 13 is arranged at the center of the tip of the robot arm 1. You may attach and detach 15. In the modification shown in FIG. 6B, the driver bit 15 is not provided with the strain cage 17.

  Next, a robot hand of a seventh example according to the embodiment of the present invention will be described with reference to FIG. 7, but detailed description of the same configuration as that of the sixth example will be omitted. In the driver bit 15 of this example, a rotary motor 18 that rotates the driver 15b about the axis with respect to the attaching / detaching part 15a is provided between the attaching / detaching part 15a and the driver 15b. Therefore, by attaching the attaching / detaching portion 15a of the driver bit 15 to the central sucker portion 13 of the robot arm 1 and driving the rotation motor 18 of the driver bit 15, the driver 15b at the tip rotates about the axis. Yes.

  FIG. 7B shows a further modification of this example. As shown in the figure, the driver bit 15 of this example is applied to a robot hand in which the central suction cup 13 is arranged at the center of the tip of the robot arm 1. You may attach and detach and use.

It is explanatory drawing of the robot hand of the 1st example in embodiment of this invention, (a) has shown the initial position, (b) has shown the holding | maintenance attitude | position. It is explanatory drawing of the robot hand of the 2nd example in embodiment of this invention, (a) has shown the initial position, (b) has shown the holding | maintenance attitude | position. It is explanatory drawing of the robot hand of the 3rd example in embodiment of this invention, (a) has shown the initial position, (b) has shown the holding | maintenance attitude | position. It is explanatory drawing of the robot hand of the 4th example in embodiment of this invention, (a) has shown the initial position, (b) has shown the holding | maintenance attitude | position. It is explanatory drawing of the robot hand of the 5th example in embodiment of this invention, (a) has shown the initial position, (b) has shown the holding | maintenance attitude | position. It is explanatory drawing of the robot hand of the 6th example in embodiment of this invention, (a) has shown the state which performs a fastening operation, (b) has shown the state which performs the fastening operation in a modification. It is explanatory drawing of the robot hand of the 7th example in embodiment of this invention, (a) is the state which performs a fastening operation | work, (b) has shown the state which performs a fastening operation | work in a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Robot arm part 2 Finger part 3 Suction cup part 5 Joint part 9a Finger joint part 9b Finger joint part 10 Joint part 11 Ultrasonic motor 12 Shape memory alloy 13 Central sucker part 15 Driver bit 15b Driver 16 Screw

Claims (11)

  A robot hand comprising a plurality of finger portions extending from the tip of the robot arm portion, and a suction cup portion disposed on each finger portion, wherein the posture of each suction cup portion is provided to be changeable. .   The robot hand according to claim 1, further comprising a joint portion that connects the robot arm portion and each finger portion so that the angle can be freely changed.   The finger part is formed by a plurality of phalanx parts and a joint part that connects adjacent phalanx parts so that the angle can be changed, and a sucker part is arranged in each phalanx part. 2. The robot hand according to 2.   4. The robot hand according to claim 2, further comprising an angle detector installed at the joint.   The robot hand according to any one of claims 2 to 4, further comprising an angle changing actuator installed at the joint.   The robot hand according to claim 5, further comprising an ultrasonic motor as the angle changing actuator.   The robot hand according to claim 5, further comprising a shape memory alloy as the angle changing actuator.   The robot arm includes a central suction cup disposed at the center of the tip, and a driver bit that is detachably attached to the central suction cup and has a driver at the tip. The robot hand according to one item.   9. The robot hand according to claim 8, further comprising: a rotation motor that integrally rotates a driver bit so that a driver at a tip rotates about an axis on the robot arm side.   9. The robot hand according to claim 8, further comprising a rotary motor that rotates a driver at a tip end about an axis on a driver bit side.   The robot hand according to any one of claims 8 to 10, further comprising drop-off detection means for detecting that the screw has dropped from the driver bit.

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