JP2007216332A - Actuator, finger unit using it, and gripping hand - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator having a small, simple bending mechanism and exerting a large force and provide a finger unit using it and a gripping hand capable of gripping even a fragile object certainly without causing breakage. <P>SOLUTION: The actuator is equipped with skeletons 5a and 5b having a link part, an expansion/contraction part 1a consisting of electroactive polymer and formed on the skeletons, and a covering part 4 to cover the skeletons and the expansion/contraction part, and is to put the skeletons into bending motions by impressing a voltage on the expansion/contraction part to cause it to make expansion and contraction, wherein the covering part is formed from a resilient material having a large expansion/contraction ratio, while the link part is configured so that one of the skeletons 5a is formed in a U-shape pinching the expansion/contraction part and the two skeletons 5a and 5b are coupled together through a crank arm 6 in such a manner as able to bend freely. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an actuator that performs bending or turning motion using an electroactive polymer as a displacement portion.

Electroactive polymers capable of flexible operation generally require a bias mechanism, and an actuator having a bending mechanism as shown in FIG. 11 has been proposed as a configuration in which a conventional electroactive polymer and a bias mechanism are integrated. (Patent Document 1).
FIG. 11 is a side sectional view of an actuator using a conventional electroactive polymer. In FIG. 11, this actuator includes an expansion / contraction part 1 made of an electroactive polymer and a lead 2 for applying a voltage to the expansion / contraction part (electroactive polymer) 1, and the expansion / contraction part 1 is provided with a bias mechanism 3 such as a spring. ing. By applying a positive potential from one of the leads 2 and applying a negative potential from the other, the expansion / contraction part 1 tries to expand. At this time, a force in a direction to extend the expansion / contraction part 1 is generated by the bias mechanism 3, thereby Expresses a force in the stretching direction. Further, when the expansion / contraction part 1 contracts by applying a potential opposite to that at the time of expansion to the lead 2, the expansion / contraction part 1 contracts against the force of the bias mechanism 3, thereby expressing a force in the contraction direction. It was.

In addition, in a conventional finger unit of a robot hand, a finger unit having one degree of freedom per joint is configured using an electromagnetic motor as a drive source in order to grip an object. The configuration includes pulleys that are freely fitted to the shafts of the joints of the finger unit. The pulleys of the joints are connected to each other by a belt and are driven by an electromagnetic motor (Patent Document 2 (FIG. 1). )). If the object to be grasped is a fragile object such as an egg, a force sensor is attached to the fingertip so that the object is not broken when the object is grasped, and flexible grasping is performed while feeding back sensor information. (For example, Non-Patent Document 1 (Table 2)).
JP 2000-83389 (8 pages, FIG. 1) JP-A-5-301191 (2-3 pages, FIG. 1) Kawasaki et al. “Gifu Hand III”, Journal of the Robotics Society of Japan, January 2004 (Vol. 22), p. 55-56 (page 56, table 2)

  However, when the electroactive polymer as in Patent Document 1 is used, there is a problem that the apparatus becomes large because the bias mechanism is integrated. Further, in the conventional method such as Patent Document 2, the spiral movement of the joint cannot be performed, and when the object is gripped, the object is crushed or dropped and damaged, or it is difficult to grip the object. There was also a problem. Furthermore, when many sensors are used as in Non-Patent Document 1, there is a problem that the unit becomes large due to the size of the sensor itself, the sensor cable, and the like by arranging the sensors.

  The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide an actuator that has a small and simple bending mechanism and generates a large force. It is another object of the present invention to provide a finger unit and a gripping hand that can reliably grip a fragile object without being damaged by performing a spiral motion.

In order to solve the above problems, the present invention is configured as follows.
The invention according to claim 1 is provided with a skeleton having a link portion, a stretchable portion made of an electroactive polymer provided on the skeleton, and a covering portion that covers the skeleton and the stretchable portion. In the actuator that bends and moves the skeleton by applying a voltage to expand and contract the expansion / contraction part, the covering part is an elastic body having a high degree of expansion and contraction, and the link part is a U-shape that sandwiches the expansion / contraction part. And one of the skeletons and the other of the skeletons are flexibly coupled by a crank arm.

  The invention according to claim 2 includes a skeleton having a link portion, an expansion / contraction portion made of an electroactive polymer provided on the skeleton, and a covering portion that covers the skeleton and the expansion / contraction portion. In the actuator that bends and moves the skeleton by applying a voltage to expand and contract the expansion / contraction section, the covering section is an elastic body having a large expansion / contraction degree, the expansion / contraction sections are first and second, and the link The portion is formed in a U-shape with one of the skeletons sandwiching the first stretchable portion, and one of the skeletons and the other of the skeletons are flexibly coupled by a crank arm, and the crank arm and the other of the skeletons The second stretchable part is provided so as to bend in a direction different by 90 ° with respect to the bending direction of the first stretchable part, and bendable in two directions.

  According to a third aspect of the present invention, the crank arm is a U-shaped U-shaped member, a joint that is pivotally supported by one end of the telescopic portion and is freely coupled to the shaft, and a shaft at one open end of the skeleton. And a rotating shaft that is supported to freely rotate.

According to a fourth aspect of the present invention, the other skeleton is a U-shaped member that sandwiches the second telescopic portion, and the support provided on the crank arm, the other skeleton, and the support are coupled flexibly. Providing a joint and a force transmission part for transmitting the force generated in the second extension part, and flexibly connecting the crank arm and the skeleton made of the other U-shaped member; Is arranged so that the principle of the lever works by using the support column as a fulcrum.
A fifth aspect of the present invention is a finger unit using at least one actuator according to the first to fourth aspects.
The invention described in claim 6 is a gripping hand configured by using at least one finger unit according to claim 5.
Is.

  According to the first aspect of the present invention, since the electroactive polymer is biased by the stretchability of the covering portion, an actuator having a small and simple bending mechanism can be realized.

  According to the second and third aspects of the present invention, since a spiral motion can be performed, a fragile object can be gripped flexibly, and a sensor is not required, so an inexpensive finger unit is configured with a simple configuration. be able to. In addition, since no motor or gear is used, the operation sound is quiet and suitable for personal use.

  According to the fourth aspect of the present invention, a large generating force can be obtained by utilizing the principle of leverage.

  According to the fifth and sixth aspects of the invention, an inexpensive finger unit and gripping hand can be configured with a simple configuration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a side sectional view of an actuator having a bending mechanism according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line A-A 'in FIG. In the figure, 1 is a stretchable part made of an electroactive polymer, 2 is a lead, 4 is a rubber covered part having elasticity, 5a and 5b are plastic skeletons, 6 is a crank arm, 7 is a rotating shaft, 8a and 8b is a joint. A lead 2 is connected to the stretchable part (electroactive polymer) 1. The stretchable part 1 is connected to the skeleton 5a and the crank arm 6 by a joint 8a and a joint 8b, respectively. Further, a skeleton 5 b is coupled to the tip of the crank arm 6. One end of each of the skeleton 5a and the skeleton 5b is coupled to the covering portion 4.

  The difference between the present invention and Patent Document 1 is that the electroactive polymer bias mechanism is placed on the covering portion to enable downsizing, and the covering portion has stretchability.

Next, the operation of this embodiment will be described with reference to FIG.
FIG. 3 is a side sectional view showing the operation of the actuator of the present invention.
(1) First, as shown in FIG. 3 (a), when the stretchable portion 1 is not controlled, the stretchable portion 1 is biased by the stretchable force of the covering portion 4 and is not bent.
(2) Next, as shown in FIG. 3 (b), the telescopic portion 1 can be bent by being controlled by a controller (not shown). In this operation, the expansion / contraction part 1 is energized and extended from the lead 2, and the expansion / contraction part 1 pushes the crank arm 6 in the direction of the skeleton 5 b, thereby overcoming the expansion / contraction force of the covering part 4 and bending around the rotation shaft 7. Make it work. At this time, the joint 8a and the joint 8b can be freely rotated so as to be rotatable about the rotation shaft 7.
(3) Further, as shown in FIG. 3C, the degree of bending can be largely controlled by increasing the magnitude of the voltage applied to the expansion / contraction part 1.

4 is a side sectional view of an actuator showing a second embodiment of the present invention, and FIG. 5 is a sectional view taken along the line BB ′ of FIG. In the figure, 1a is a first stretchable part made of an electroactive polymer, 1b is a second stretchable part made of an electroactive polymer, 9 is a support, 10 is a fixed body, 11 is a force transmission part for transmitting the generated force, Reference numeral 12 denotes a bending unit, and 13 denotes an inner / outer rotation unit. Other symbols are the same as those in the first embodiment.
The bending unit 12 includes a first extendable portion 1a, a lead 2a, a plastic skeleton 5a, a crank arm 6, a rotating shaft 7, and joints 8a and 8b. The first extendable portion 1a includes a joint 8a and a joint. 8b is connected to the skeleton 5a and the crank arm 6 respectively. A lead 2a is connected to the first extendable part 1a. The inner / outer rotation unit 13 includes a second expansion / contraction part 1b, a lead 2b, a plastic skeleton 5b, a support column 6, joints 8c, 8d and 8e, a fixed body 10, and a force transmission part 11. One end of the portion 1b is fixed to a fixed body 10 coupled to the skeleton 5b, and a lead 2b is connected to the second expandable portion 1b. In addition, the bending unit 12 and the inner / outer rotation unit 13 include a force transmission portion 11 attached to one end of the second telescopic portion 1b of the inner / outer rotation unit 13 via a joint 8d, and a joint 8e to the crank arm 6 of the bending unit 12. It is combined by being attached through. Further, one end of the skeleton 5 a of the bending unit 12 and the skeleton 5 b of the inner / outer rotation unit 13 are respectively coupled to the covering portion 4.

  The present invention differs from Patent Document 1 and Patent Document 2 in that the electroactive polymer bias mechanism is attached to the covering portion to enable downsizing, the spiral motion is possible, and the object is reliably utilized by utilizing the principle of the lever. Grabbing and the electroactive polymer is a flexible object.

Next, the operation of this embodiment will be described in two directions along the BB ′ cross section of FIG.
First, the bending unit 12 that bends in the direction perpendicular to the BB ′ cross section of FIG. 4 will be described with reference to FIG.
(1) As shown in FIG. 6 (a), in a state where the first stretchable portion 1a is not controlled, the stretchable force of the covering portion 4 serves as a bias for the first stretchable portion 1a and is not bent.
(2) Next, as shown in FIG. 6 (b), the first telescopic portion 1a can be bent by being controlled by a controller (not shown). In this operation, the first expansion / contraction part 1a is energized and extended from the lead 2a, and the first expansion / contraction part 1a pushes the crank arm 6 in the direction in which the column 6 is located, thereby overcoming the expansion / contraction force of the covering part 4 and rotating shaft. A bending operation is performed with 7 as the center. At this time, the joint 8a and the joint 8b can be freely rotated so as to be rotatable about the rotation shaft 7.
(3) Further, as shown in FIG. 3C, the degree of bending can be largely controlled by increasing the magnitude of the voltage applied to the electroactive polymer 1.

Next, the inner / outer rotation unit 13 that performs the bending operation in the BB ′ cross section of FIG. 4 will be described with reference to FIG.
(1) As shown in FIG. 7 (a), in a state where the second stretchable portion 1b is not controlled, the stretchable force of the covering portion 4 serves as a bias for the second stretchable portion 1b and is not bent.
(2) Next, as shown in FIGS. 7B and 7C, the second extendable portion 1b can be bent by being controlled by a controller. In this operation, the second expansion / contraction part 1b is energized from the lead 2b to expand or contract, and the second expansion / contraction part 1b pushes or pulls the force transmission part 11 toward the crank arm, thereby overcoming the expansion / contraction force on the covering part 4. A bending operation is performed around the joint 8c. At this time, the joint 8d and the joint 8e can be freely rotated so that the joint 8c can be rotated.

  Further, by combining the bending operations of the bending unit 12 and the inner / outer rotation unit 13 described above, that is, by simultaneously controlling the first extension / contraction part 1a and the second extension / contraction part 1b, the inner / outer rotation unit 13 is controlled with respect to the bending unit 12. Turns.

  FIG. 8 is a side sectional view showing a third embodiment of the present invention. The support column 6 of the inner / outer rotation unit 13 is arranged so as to be offset from the center of the crank arm 6 to the side opposite to the force transmission portion 11. In this state, the second expansion / contraction part 1b is energized and expanded / contracted, so that the bending operation is performed in the AA ′ cross section around the joint 8c. At this time, since the column 6 is offset to the side opposite to the force transmitting portion 11, the generated force of the second expansion / contraction portion 1b is expanded by the lever principle to obtain a large bending force.

FIG. 9 is a side sectional view showing a fourth embodiment of the present invention. In FIG. 9, 14a is a first joint, 14b is a second joint, and 14c is a third joint. The first joint 14a includes a bending unit 12a and an internal / external rotation unit 13, the second joint 14b includes a bending unit 12b, and the third joint 14c includes a bending unit 12c.
By controlling these bending units 12a, 12b, and 12c independently by a controller, as shown in FIGS. 9 (b) and (c), the first joint 14a, the second joint 14b, and the third joint 14c, respectively. It can be moved independently and the bending mechanism can be bent freely. In addition, the first joint 14a can be turned by controlling the bending unit 12a and the inner / outer rotation unit 13 independently by a controller. In FIG. 9, the number of joints is three, but a plurality of bending units 12 may be arranged to form a multi-joint. In FIG. 9, the inner / outer rotation unit 13 is disposed only in the first joint 14a. However, the inner / outer rotation unit 13 may be disposed in any joint, and the turning motion is possible in any joint. Furthermore, by applying the turning operation of this bending mechanism to the finger unit, it is possible to construct an inexpensive finger unit with a simple configuration.

FIG. 10 is a side sectional view showing a fifth embodiment of the present invention. In FIG. 10, 15a is a first finger and 15b is a second finger. The first finger 15 a and the second finger 15 b are constituted by the bending unit 12, the inner / outer rotation unit 13, and the covering portion 4.
By controlling the bending unit 12 and the inner / outer rotation unit 13 independently by a controller, the first finger 15a and the second finger 15b can be bent and swiveled.
In the present embodiment, the number of joints is one for both the first finger 15a and the second finger 15b, but a plurality of bending units 12 and adduction / extraction units 13 may be arranged to form a multi-joint. Moreover, although it was set as the structure with two fingers, the 1st finger 15a and the 2nd finger 15b, it is also possible to arrange | position three or more fingers. Furthermore, by applying this finger to the gripping hand, it is possible to construct an inexpensive gripping hand with a simple configuration.

1 is a side sectional view of an actuator showing a first embodiment of the present invention. Sectional view along A-A 'in FIG. Side sectional view showing the operation of the first embodiment of the present invention. Side sectional view of an actuator showing a second embodiment of the present invention Sectional view along B-B 'in FIG. Side sectional view showing the operation of the second embodiment of the present invention. Side sectional view showing another operation of the second embodiment of the present invention. Side sectional view showing a third embodiment of the present invention. Side sectional view showing a fourth embodiment of the present invention. Side sectional view showing a fifth embodiment of the present invention. Side sectional view showing a conventional actuator

Explanation of symbols

1 Stretchable part (electroactive polymer)
1a 1st expansion-contraction part 1b 2nd expansion-contraction part 1b
2, 2a, 2b Lead 3 Bias mechanism 4 Covering portion 5a, 5b Skeleton 6 Crank arm 7 Rotating shaft 8a, 8b, 8c, 8d, 8e Joint 9 Strut 10 Fixed body 11 Force transmitting portion 12, 12b, 12c Bending unit 13 Inside / outside Rolling unit 14a first joint 14b second joint 14c third joint 15a first finger 15b second finger

Claims (6)

A skeleton having a link portion; an elastic portion made of an electroactive polymer provided on the skeleton; and a covering portion that covers the skeleton and the elastic portion; and applying a voltage to the elastic portion to In an actuator that flexes and moves the skeleton by expanding and contracting,
The covering portion is an elastic body having a large degree of expansion and contraction, the link portion is formed in a U shape with one of the skeletons sandwiching the expansion and contraction portion, and one of the skeletons and the other of the skeletons are flexibly coupled by a crank arm. An actuator characterized by that. A skeleton having a link portion; an elastic portion made of an electroactive polymer provided on the skeleton; and a covering portion that covers the skeleton and the elastic portion; and applying a voltage to the elastic portion to In an actuator that flexes and moves the skeleton by expanding and contracting,
The covering portion is an elastic body having a high degree of expansion and contraction, the expansion and contraction portions are first and second, and the link portion is formed in a U shape with one of the skeletons sandwiching the first expansion and contraction portion. One side of the frame and the other side of the skeleton are connected to be freely bent by a crank arm, and bend between the crank arm and the other side of the skeleton in a direction different by 90 ° with respect to the bending direction of the first telescopic portion. The actuator is characterized in that the second expansion / contraction part is provided to be bent in two directions.   The crank arm is a U-shaped member having a U-shaped cross section, and is connected to a joint that is pivotally supported by one end of the expansion and contraction part and is freely coupled to and freely supported by one open end of the skeleton. The actuator according to claim 1, further comprising a rotating shaft.   The other skeleton is a U-shaped member that sandwiches the second expansion / contraction part, a support provided on the crank arm, a joint that flexibly connects the other skeleton and the support, and the second extension / contraction part A force transmission portion for transmitting the force generated in the step, the crank arm and the other U-shaped skeleton are flexibly coupled, and the second expansion and contraction portion uses the support as a fulcrum, and the principle of the lever The actuator according to claim 2, wherein the actuator is arranged to work.   A finger unit using at least one actuator according to claim 1.   A gripping hand comprising at least one finger unit according to claim 5.

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