JP2015166117A - robot arm - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a robot arm which improves the torque of an actuator, and suppresses the twisting and vibrations of a joint portion to improve positioning accuracy.SOLUTION: A robot arm includes: a joint portion which has first and second rigid members to which first and second links capable of sealing a fluid inside are respectively attached, a shaft portion for rotatably supporting the first and second rigid members, an expansion member for acting pressure on a pressing piece of the second rigid member, and friction generating means disposed between the pressing pieces of the first and second rigid members while one end side of first and second sheet members attached to the first and second rigid members on the other end side are alternately laminated, pressing the pressing piece of the second rigid member by the expansion member, and tightly contacting the one sides of the first and second sheet members by the pressing pieces of the first and second rigid members to generate friction force; and a pair of fluid pressure actuators antagonistically disposed on the joint portion so as to rotate the joint portion.

Description

  The present invention relates to a robot arm using an inflatable structure.

  Conventionally, various robot arms having an inflatable structure that are operated using a fluid such as air as driving energy have been proposed. In the robot arm having such an inflatable structure, it is possible to reduce the weight by using a soft material, and thus it is possible to ensure safety in contact with a human body.

  As a robot arm using an inflatable structure, for example, by applying pressure from a bent state to a connecting portion of a structural skeleton formed by enclosing a fluid with a constant pressure, a bent portion caused by shape recovery force is applied. A robot arm in which a plurality of actuators that use torque as a driving force are arranged is disclosed (for example, see Non-Patent Document 1).

Daisuke Maruyama, Hitoshi Kimura, Michihiko Koseki, Norio Ino, “Flexible mechanical system using hydrodynamic framework (avoidance of stress concentration based on nonlinear finite element analysis and comparison of driving force characteristics)”, Japan Fluid Power System Society Proceedings, Vol.41, no.3, pp.1-9, 2010.

  However, with a conventional robot arm having an inflatable structure, it is difficult to grip a heavy object due to insufficient torque of the actuator. In addition, in the inflatable robot arm, since the joint portion to which the link is connected is made of a soft material, a twist occurs between the links, and the positioning accuracy of the hand is lowered. Further, since there is no viscous element in the joint, there is a problem that vibration occurs in the joint and the positioning accuracy is lowered.

  The present invention has been made in view of the various problems as described above, and can improve the torque of the actuator and improve the positioning accuracy by suppressing the twisting phenomenon and vibration in the joint portion. An object of the present invention is to provide a robot arm that can be used.

  In order to achieve the above object, the robot arm according to claim 1 is capable of enclosing a fluid inside the bag by a first link formed in a bag-like structure capable of enclosing the fluid in a plastic material. A second link formed in a bag-like structure; a joint that connects the first link and the second link; and a pair that is arranged antagonistically at the joint to rotate the joint. A fluid pressure actuator, wherein the joint includes a first rigid member to which the first link is attached, a second rigid member to which the second link is attached, and the first rigid member. And a shaft portion that rotatably supports the second rigid member, and a plastic material, and a fluid is supplied to the inside to expand, thereby supporting the pressing piece of the second rigid member. An expansion member for applying pressure to the axial direction side of the shaft, a thin film-like first sheet member having one end attached to the first rigid member, and a thin film-like member having one end attached to the second rigid member The second sheet member is disposed between the pressing piece of the second rigid member and the pressing piece of the first rigid member in a state where a plurality of the other end sides of each of the second sheet members are alternately stacked. The pressing piece of the rigid member is pressed, and the other end sides of the first sheet member and the second sheet member are held in close contact with the pressing piece of the second rigid member and the pressing piece of the first rigid member. And a pair of fluid pressure actuators each having a bag-like structure in which a fluid chamber capable of containing a working fluid is formed by a plastic material. Continuous A plurality of adjacent fluid chambers of the bag-like structure are configured to allow the working fluid to flow through the communication holes, and expand when the working fluid is supplied to the fluid chambers, The first rigid body member or the second rigid body member is rotated by rotating in a fan shape.

  The robot arm according to claim 2, wherein the plurality of bag-like structures are provided with distances from a base end to a tip located on a fulcrum side when the fan-like structure is rotated in a fan shape on both ends. It is comprised so that it may become short as it goes to the said bag-like structure provided in the center side.

  The robot arm according to claim 3 is characterized in that the pair of fluid pressure actuators are each formed of high density polyethylene (HDPE).

  According to a fourth aspect of the present invention, in the robot arm, the first link and the second link each have a hollow portion, and the outer peripheral portion includes a fluid bag having a bag-like structure capable of enclosing a fluid therein in the outer peripheral direction. It is characterized by being provided with a plurality.

  According to the robot arm according to claim 1, the first link and the second link formed in a bag-like structure capable of enclosing a fluid therein with a plastic material are supported by the shaft portion so as to be rotatable. Since it is respectively attached to the member and the second rigid body member, it is possible to prevent twisting between the first link and the second link in the joint portion, and to improve the positioning accuracy. In addition, the joint portion has a plurality of alternately on the other end sides of the thin film-like first sheet member whose one end is attached to the first rigid member and the thin film-like second sheet member whose one end is attached to the second rigid member. In a laminated state, the pressing piece of the second rigid member is pressed by the expansion member that is disposed between the pressing piece of the second rigid member and the pressing piece of the first rigid member and that is supplied with fluid and expands therein. Friction force generating means for generating a friction force by sandwiching the other end sides of the first sheet member and the second sheet member between the pressing piece of the second rigid member and the pressing piece of the first rigid member. Therefore, the pressure applied to the pressing piece of the second rigid member is adjusted by the expansion member according to the rotation speed of the joint, and the first sheet member and the second sheet member are brought into close contact with each other to generate a frictional force. To give viscosity. Can, it is possible to suppress the vibration of the joint portion. As a result, even when the object is gripped, blur due to vibration of the joint can be suppressed. In addition, a plurality of bag-like structures each having a fluid chamber in which a working fluid can be accommodated by a plastic material are continuously provided, and the working fluid flows through the fluid chambers of the adjacent bag-like structures via the communication holes. A pair of fluid pressure actuators that are configured to be capable of expanding and fan-like rotation by supplying a working fluid to each of the fluid chambers are arranged antagonistically at the joints. The torque generated can be improved.

  According to the robot arm according to claim 2, the plurality of bag-like structures have a bag-like structure in which the distance from the base end to the tip end located on the fulcrum side when rotating in a fan shape is provided on both end sides. Since the volume of the fluid chamber of each bag-like structure can be suppressed from increasing, the fluid chamber is supplied to each fluid chamber. The torque generated in the joint can be efficiently improved while reducing the supply amount of the working fluid.

  According to the robot arm of the third aspect, since the pair of fluid pressure actuators are formed of high-density polyethylene (HDPE), the weight can be reduced and the operation supplied to each fluid chamber can be achieved. The pressure resistance against the fluid can be improved.

  According to the robot arm of the fourth aspect, the first link and the second link have a hollow portion, and the outer peripheral portion is continuous with a bag-like structure fluid bag capable of enclosing a fluid in the outer peripheral direction. As a result, the strength can be improved and a tube for supplying fluid to a pair of fluid pressure actuators and the like can be accommodated in the hollow portion.

It is a schematic front view which shows an example of the robot arm which concerns on embodiment of this invention. It is a schematic plane sectional view showing an example of the 1st link and the 2nd link. It is a schematic front view which shows an example of a joint part. It is a principal part schematic plan view which shows an example of a joint part, Comprising: (a) has shown the state when the friction force is not provided, (b) has shown the state when the friction force is provided. ing. It is a schematic front view which shows an example of a fluid pressure actuator. It is the sectional view on the AA line in FIG. It is a schematic front view which shows an example of a 1st sheet member and a 2nd sheet member. It is a schematic front view which shows the state by which the 1st sheet member and the 2nd sheet member were laminated | stacked. It is a schematic sectional drawing which shows an example of a horizontal turning mechanism.

  Hereinafter, a robot arm 1 according to an embodiment of the present invention will be described with reference to the drawings. The robot arm 1 is, for example, for performing an operation of gripping an object (not shown) and carrying it to a target place, and as shown in FIG. 1, a bag in which a fluid can be enclosed. A joint 3 that connects the first link 2a and the second link 2b formed in the shape of a structure, and a pair of fluid pressure actuators 4a that are antagonistically arranged in the joint 3 to rotate the joint 3 , 4b. Further, the robot arm 1 is provided with a horizontal turning mechanism 6 on the base 5 so as to be able to turn horizontally, and a gripping portion 7 for gripping an object is provided at the tip side of the link 2c. It is provided via the connecting member 8 attached to the. 1, for convenience of explanation, a fluid pump that is a supply source for supplying fluid to each part of the pair of fluid pressure actuators 4a, 4b, etc., and a tube connected from the fluid pump to the supply / discharge holes of each part Etc. are omitted.

  Each of the first link 2a and the second link 2b is formed in a bag-like structure capable of enclosing a fluid with a thin-film plastic material, and has rigidity by an internal pressure from the fluid encapsulated therein. Have. As shown in FIG. 2, the first link 2 a and the second link 2 b have a hollow portion 21, and the outer peripheral portion is formed by a plurality of fluid bags 22 having a bag-like structure capable of enclosing a fluid therein. ing. The plurality of fluid bags 22 are continuously provided in the outer circumferential direction, and the interiors of the adjacent fluid bags 22 are formed so as to communicate with each other so that fluid can flow therethrough. Further, at least one fluid bag 22 is provided with a supply / discharge hole 23, and fluid is supplied from a fluid pump provided outside so that the internal fluid pressure can be adjusted.

  As a plastic material used for forming the fluid bag 22, for example, polyethylene (PE) or polypropylene (PP) can be used, and the first link 2a and the second link 2b can be manufactured at low cost. . Since the first link 2a and the second link 2b are formed using such a lightweight and soft material, safety can be ensured even when they are in contact with the human body. Further, since the first link 2a and the second link 2b are formed so as to have the hollow portion 21, as shown in FIG. 2, each portion such as a pair of actuators 4a and 4b from the fluid pump is formed in the hollow portion 21. A tube 9 for supplying a fluid can be accommodated. In the present embodiment, the outer peripheral portions of the first link 21 and the second link 22 are shown as being formed by four fluid bags 22, but the number of fluid bags 22 is not particularly limited. However, it should just be provided so that the hollow part 21 can be formed. Moreover, the structure of the 1st link 21 and the 2nd link 22 is comprised by the substantially cylindrical shape with the one fluid bag which does not have the hollow part 21, and the tube 9 for supplying the fluid to each part is made into the 1st link 21 and You may arrange | position so that the outer peripheral surface of the 2nd link 22 may be met. In that case, you may comprise so that the intensity | strength with respect to an internal pressure may be improved by using the material which piled up and adhered polyethylene, polypropylene, and polyethylene in order from the outer peripheral surface side, for example.

The joint portion 3 rotatably connects the first link 2a and the second link 2b, and as shown in FIGS. 3 and 4, a first rigid member 31 to which the distal end side of the first link 2a is attached. A second rigid member 32 to which the proximal end side of the second link 2b is attached, a shaft portion 33 that rotatably supports the first rigid member 31 and the second rigid member 32,
An expansion member 34 that expands when a fluid is supplied therein, a first sheet member 35 that has one end attached to the first rigid member 31, and a second sheet member 36 that has one end attached to the second rigid member 32. I have. In FIG. 4, for convenience of explanation, the pair of fluid pressure actuators 4a and 4b are not shown.

  The first rigid member 31 and the second rigid member 32 are each formed of a rigid material. As shown in FIGS. 3 and 4, the first rigid member 31 includes an attachment portion 31 a provided with an insertion hole for attachment in a state where the distal end side of the first link 2 a is inserted, and a shaft portion from the inner peripheral surface. And a pressing piece 31b formed so as to protrude in a direction perpendicular to the axial direction of 33. The pressing piece 31b is formed in a substantially circular shape when viewed from the front side, and has an insertion hole 31c through which the shaft portion 33 can be inserted. The second rigid member 32 includes an attachment portion 32a provided with an insertion hole for attachment in a state where the proximal end side of the second link 2b is inserted, and one end in the width direction parallel to the axial direction of the shaft portion 33. And a pressing piece 32b formed so as to protrude from the side in a direction orthogonal to the axial direction of the shaft portion 33. Similarly to the pressing piece 31b, the pressing piece 32b is formed in a substantially circular shape when viewed from the front side, and has an insertion hole 32c through which the shaft portion 33 can be inserted. As a rigid material for forming the first rigid member 31 and the second rigid member 32, for example, an ABS resin that is lightweight and excellent in impact resistance can be suitably used. The first rigid member 31 and the second rigid member 32 are rotatably supported by the shaft portion 33, and the end portion of the shaft portion 33 is located on the outer peripheral surface of the first rigid member 31. .

  The expansion member 34 is formed in a bag shape from a plastic material, and is configured to expand in the axial direction of the shaft portion 33 when a fluid is supplied to the inside. As shown in FIG. 4, the expansion member 34 is formed in a donut shape having an insertion hole 34 a through which the shaft portion 33 can be inserted at a substantially central portion. When the fluid is supplied to the inside of the expansion member 34, as shown in FIG. 4B, the expansion member 34 expands toward the axial direction side of the shaft portion 33, and the pressing piece 32 b of the second rigid member 32 is the shaft of the shaft portion 33. Pressure is applied to the pressing piece 32b so as to move inward in the direction (rightward in the figure). As a plastic material for forming such an expansion member 34, for example, polyethylene or the like can be used. Although not shown in detail, a supply / discharge hole is formed in the expansion member 34 so that a fluid is supplied from a fluid pump provided outside via a tube. By adjusting, the pressure to be applied to the pressing piece 32b can be adjusted.

  As shown in FIGS. 4 and 7, the first sheet member 35 and the second sheet member 36 are each formed in the same shape by a thin film plastic material. As shown in FIG. 7, the first sheet member 35 and the second sheet member 36 are each formed in a front rear circular shape, and the shaft portion 33 can be inserted into the circular portions 35 a and 36 a having a substantially circular shape. Insertion holes 35b and 36b are formed. As a plastic material for forming the first sheet member 35 and the second sheet member 36, for example, polypropylene or the like can be used.

  One end side of the first sheet member 35 is fixed to the inner peripheral surface of the first rigid member 31, and the circular portion 35a on the other end side is rotatably supported in a state where the shaft portion 33 is inserted into the insertion hole 35b. . The second sheet member 36 has one end fixed to the inner peripheral surface of the second rigid member 32, and the circular portion 36a on the other end is rotatably supported with the shaft 33 inserted through the insertion hole 36b. Is done. Therefore, as shown in FIGS. 4 and 8, the circular portion 35a on the other end side of the first sheet member 35 and the circular portion 36a on the other end side of the second sheet member 36 are alternately stacked and stacked. Thus, the first sheet member 35 and the second sheet member 36 are disposed between the pressing piece 31 b of the first rigid member 31 and the pressing piece 32 b of the second rigid member 32. In the robot arm 1, in this state, the expansion member 34 is expanded so that the pressing piece 32 b of the second rigid member 32 moves inward in the axial direction (right direction in the drawing) of the shaft portion 33. By applying pressure to 32b, the circular portion 35a on the other end side of the first sheet member 35 and the circular portion 36a on the other end side of the second sheet member 36 are connected to the pressing piece 32b of the second rigid member 32. By being sandwiched and brought into close contact with the pressing piece 31b of the first rigid member 31, a frictional force is generated on the contact surface between the circular portion 35a and the circular portion 36a, and this frictional force can be used as a brake or the like.

  Thus, in the present embodiment, the pressing pieces 31b of the first rigid member 31 and the pressing pieces of the second rigid member 32 in a state where a plurality of the circular portions 35a and the circular portions 36a on the other end side are alternately stacked. A laminated restraining element constituted by a plurality of first sheet members 35 and second sheet members 36 disposed between the first and second sheet members 35b serves as a frictional force generating means for generating a frictional force. Further, in the first sheet member 35 and the second sheet member 36, a plurality of the other end sides are alternately stacked and laminated, and the other end side is formed in a circular shape, thereby ensuring a large contact area. It is possible to improve the binding force.

  As shown in FIG. 3, the pair of fluid pressure actuators 4 a and 4 b are antagonistically disposed on the joint portion 3 in order to rotate the joint portion 3. As shown in FIGS. 5 and 6, the fluid pressure actuators 4 a and 4 b each have a continuous bag-like structure 41 (41 a to 41 d) in which a fluid chamber 42 in which a working fluid can be stored is formed by a plastic material. The fluid chambers 42 of the adjacent bag-like structures 41 are configured so that the working fluid can flow through the communication holes 43, respectively. In the fluid pressure actuators 4a and 4b, the working fluid is supplied from a fluid pump (not shown) provided outside each fluid chamber 42 through the tube 9 connected to the supply / exhaust hole 44. Inflates to rotate.

  Further, as shown in FIG. 5, the plurality of bag-like structures 41 of the fluid pressure actuators 4 a and 4 b are connected to the bag-like structures 41 a to 41 d from the base end o located on the fulcrum side when rotating in a fan shape. The distance from the tips a to d is formed so as to decrease from the bag-like structure 41a located at both ends toward the bag-like structure 41d located at the center. That is, in the fluid pressure actuators 4a and 4b, the bag-like structures 41a to 41d are formed so as to be shorter in the order of the line segment oa, the line segment ob, the line segment oc, and the line segment od. Thereby, since it can suppress that the volume of each fluid chamber 42 of the bag-like structure 41 becomes large, rotational torque is efficiently reduced while reducing the supply amount of the working fluid supplied to each fluid chamber 42. Can be obtained. As a plastic material for forming such fluid pressure actuators 4a and 4b, for example, high density polyethylene (HDPE) can be suitably used. Thus, by forming the fluid pressure actuators 4a and 4b with high density polyethylene, the pressure resistance can be improved. As the working fluid to be supplied to the fluid pressure actuators 4a and 4b, for example, a gas such as air can be suitably used, but the present invention is not limited to this, and other fluids can also be used.

  As shown in FIG. 3, in the fluid pressure actuator 4a, a bag-like structure 41a located on one end side is attached to the first rigid member 31, and a bag-like structure 41a 'located on the other end side is second. The rigid member 32 is attached. Similarly to the fluid pressure actuator 4a, the fluid pressure actuator 4b has a bag-like structure 41a located on one end side attached to the first rigid member 31, and a bag-like structure 41a 'located on the other end side. The second rigid member 32 is attached. In such a state, for example, when the first link 2a side is constrained not to rotate, the fluid pressure actuator 4a rotates in a fan shape by supplying the working fluid to the fluid pressure actuator 4a. Since the torque for rotating counterclockwise around the shaft portion 33 can be applied to the second rigid member 32, the attachment portion 32a of the second rigid member 32 is applied to the attachment portion 32a of the second rigid member 32 as shown by the arrow in FIG. The attached second link 2b can be rotated counterclockwise. Further, when the second link 2b is rotated in the clockwise direction, the working fluid may be supplied to the fluid pressure actuator 4b. 3 shows an example of the fluid pressure actuators 4a and 4b in which seven bag-like structures 41 are provided. However, the number of bag-like structures 41 is not limited to this, and the joints What is necessary is just to be comprised so that it may rotate in fan shape in order to rotate the part 3. FIG. In addition, the plurality of bag-like structures 41 has a bag-like structure in which the distance from the base end o to the tips a to d of the bag-like structures 41a to 41d is located at the center from the bag-like structures 41a located at both ends. Although it forms so that it may become short toward the body 41d, it is not limited to this, It forms so that the distance from the base end o to the front-ends ad of each bag-like structure 41a-41d may become equal. May be. 5 shows an example in which the supply / discharge hole 44 is provided in the bag-like structure 41a located on one end side, but the position and number of the supply / discharge holes 44 are not particularly limited, What is necessary is just to be provided so that a working fluid can be supplied in each fluid chamber 42.

  Further, in the robot arm 1 according to the present embodiment, although not shown in detail, for example, an angular velocity sensor for detecting the rotational speed of the joint portion 3, a pressure sensor for detecting the pressure by the expansion member 34, and a fluid pressure actuator 4a, 4b, the expansion member 34, and the like. In the control unit, for example, based on detection signals obtained from the angular velocity sensor and the pressure sensor, supply of fluid to the expansion member 34 so as to increase or decrease the pressure of the expansion member 34 in proportion to the rotation speed of the joint unit 3. By controlling the above and making the frictional force generated on the contact surface between the circular portion 35a of the first sheet member 35 and the circular portion 36a of the second sheet member 36 variable, a viscous effect is obtained in the joint portion 3. Thereby, the vibration of the joint part 3 is suppressed.

  The horizontal turning mechanism 6 is provided on the base 5 so that the robot arm 1 can work in a three-dimensional space as well as in the vertical plane. As shown in FIGS. A horizontal rotation member 61 provided on the horizontal rotation member 5; fluid pressure actuators 62a and 62b for applying pressure to the horizontal rotation member 61 in the horizontal rotation direction; and a proximal end side of the horizontal rotation member 61. And a link (horizontal turning shaft) 63 that rotates as the horizontal rotating member 61 rotates.

  The horizontal rotation member 61 is provided on the base 5 so as to be horizontally rotatable via a bearing (not shown), for example. As shown in FIGS. 1 and 9, the horizontal rotation member 61 includes a link support portion 61a provided with an insertion hole for mounting in a state where the proximal end side of the link 63 is inserted, and the link support portion 61a. And four rotating pieces 61b extending radially at intervals of 90 degrees.

  The fluid pressure actuators 62a and 62b are for horizontally rotating the horizontal rotating member 61 by applying a pressure in the horizontal rotating direction to the horizontal rotating member 61. As shown in FIG. Between the rotating pieces 61b adjacent to each other. The fluid pressure actuators 62a and 62b are the same as the fluid pressure actuators 4a and 4b that are antagonistically arranged at the joint 3 described above, and expand when the fluid is supplied, and rotate in a fan shape. It is. Since the fluid pressure actuators 4a and 4b are the same as the fluid pressure actuators 62a and 62b, detailed description thereof is omitted. In the fluid pressure actuator 62a, bag-like structures 621a located on both ends are respectively attached to the rotating pieces 61b. Moreover, the bag-like structures 621b located on both ends of the fluid pressure actuator 62b are respectively attached to the rotating pieces 61b. The horizontal turning mechanism 6 is configured such that the horizontal rotating member 61 can be rotated horizontally by the differential pressure between the fluid pressure actuators 62a and the fluid pressure actuators 62b that are alternately arranged between the adjacent rotating pieces 61b. .

  The base end side of the link 63 is attached to the link support portion 61 a of the horizontal rotation member 61 and is configured to rotate with the horizontal rotation of the horizontal rotation member 61. In the robot arm 1 according to the present embodiment, as shown in FIG. 1, the distal end side of the link 63 is attached to the joint portion 3, and the link 63 and the first link 2 a are interposed via the joint portion 3. It is connected. As shown in FIG. 9, the structure of the link 63 is formed in the same shape as the first link 2a and the second link 2b with a plastic material. The structure of the link 63 is not limited to this, and a link formed in a cylindrical shape by using a plurality of thin-film plastic materials stacked to improve the strength may be used.

  As shown in FIG. 1, the grip portion 7 is attached to a connecting member 8 provided on the distal end side of the link 2 c that is coupled to the distal end side of the second link 2 b via the joint portion 3. Since the link 2c has the same structure as the first link 2a and the second link 2b, detailed description thereof will be omitted. The gripping part 7 is for gripping an object (not shown), and the three gripping parts 7 are attached to the connecting member 8 at different positions. These gripping portions 7 are disclosed in Japanese Patent Application Laid-Open No. 2014-020462, and are formed of a thin-film plastic material and can bend by supplying a working fluid. The pressure actuator is used as a gripping part. In addition, the structure of the holding part 7 is not limited to this, You may apply the holding means of the conventionally well-known inflatable structure which can hold | grip a target object.

  As described above, since the robot arm 1 according to the present invention is formed using a light and soft material, safety can be ensured even when it comes into contact with the human body. Moreover, since the robot arm 1 can be gathered small by extracting the fluid of each part, it can be moved easily and can also save space when not in use. Moreover, since the robot arm 1 can be configured very lightly, it is less affected by gravity, and can be configured to be long in a cantilever structure by connecting a large number of links via a plurality of joints 3. Is possible. Therefore, by providing an imaging means such as a camera at the tip of the robot arm 1, it is possible to observe the state in the elongated place.

  The embodiment of the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the scope of the idea of the present invention.

DESCRIPTION OF SYMBOLS 1 Robot arm 2a 1st link 2b 2nd link 21 Hollow part 22 Fluid bag 3 Joint part 31 1st rigid body member 31b Pressing piece 32 2nd rigid body member 32b Pressing piece 33 Shaft part 34 Expansion member 35 1st sheet member 36 2nd Sheet member 4a, 4b Fluid pressure actuator 41, 41a-41d Bag-like structure 42 Fluid chamber 43 Communication hole

Claims (4)

A first link formed in a bag-like structure capable of enclosing a fluid therein by a plastic material; a second link formed in a bag-like structure capable of enclosing a fluid therein by a plastic material; the first link; A robot arm comprising: a joint portion that connects the second link; and a pair of fluid pressure actuators that are arranged antagonistically at the joint portion to rotate the joint portion,
The joint portion includes a first rigid member to which the first link is attached, a second rigid member to which the second link is attached, and a shaft portion that rotatably supports the first rigid member and the second rigid member. An expansion member that is formed of a plastic material and that is supplied with fluid and expands to apply pressure to the pressing piece of the second rigid member on the axial direction side of the shaft portion; and the first rigid body The first sheet member having one end attached to the member and the second sheet member having one end attached to the second rigid body member are alternately stacked in a plurality of the other end sides. 2 disposed between the pressing piece of the rigid member and the pressing piece of the first rigid member, the pressing piece of the second rigid member is pressed by the expansion member, and the first sheet member and the second sheet member That Of the other end, has a friction force generating means for generating a frictional force by close contact across the pressing piece of the first rigid member and the pressing piece of the second rigid member,
Each of the pair of fluid pressure actuators is continuously provided with a plurality of bag-like structures each having a fluid chamber in which a working fluid can be accommodated by a plastic material, and the adjacent fluid chambers of the bag-like structures are: The working fluid is configured to be able to flow through the communication hole. The working fluid is supplied to the fluid chambers to expand and rotate in a fan shape, so that the first rigid member or the second member is rotated. A robot arm characterized by rotating a rigid member.   The plurality of bag-like structures have a bag-like structure in which a distance from a base end to a tip located on a fulcrum side when rotating in a fan shape is provided on the center side from the bag-like structure provided on both end sides. The robot arm according to claim 1, wherein the robot arm is configured to become shorter toward the body.   3. The robot arm according to claim 1, wherein each of the pair of fluid pressure actuators is made of high density polyethylene (HDPE). 4.   The first link and the second link have a hollow portion, and the outer peripheral portion is formed by continuously providing a plurality of bag-like fluid bags capable of enclosing a fluid in the outer peripheral direction. The robot arm according to claim 1, wherein the robot arm is a robot arm.

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