JP2020121354A - Robot arm - Google Patents

Abstract

To achieve a robot arm which has high degrees of freedom in motion and less restrictions on operations.SOLUTION: A robot arm 1 includes: a plurality of links L which can individually control lengths; a joint J such as a ball joint for connecting the links L; and a covering section 12 which covers the whole. An operation like a human tongue can be performed as a whole. For instance, when the link L along a longitudinal direction is extended on a lower surface side and the link L along the longitudinal direction on an upper surface side is contracted, the robot arm 1 can be rounded so that a side face view shape becomes a U-shape. Alternatively, when the link L along a right and left direction is extended on the lower surface side and the link L along the right and left direction is contracted on the upper surface side, the robot arm 1 can be rounded so that a front face view shape becomes a U-shape. Alternatively, when the link L along a vertical direction is extended and the link L along the right and left direction is contracted, a cross section of the robot arm 1 can be rounded and thickness of the robot arm 1 can be increased.SELECTED DRAWING: Figure 1

Description

The present invention relates to a robot arm.

A conventional robot arm is generally configured by connecting links having a certain length with a joint. Such a robot arm operates like a human arm by changing the angle formed by adjacent links via a joint.

Further, Patent Document 1 discloses a flexible arm configured by connecting three radially arranged rod-shaped bodies with a link. This flexible arm can change the length and the bending direction by rotating three servo motors.

JP 61-61788 (Published March 29, 1986)

However, the conventional robot arm has a problem that it has a low degree of freedom of movement and has many restrictions on movement. For example, bending/stretching motions and stretching/shrinking motions were possible, but rolling motions were not possible.

One aspect of the present invention has been made in view of the above problems, and an object of the present invention is to realize a robot arm that has a high degree of freedom of movement and has few restrictions on operations.

In order to solve the above problems, a robot arm according to an aspect of the present invention is a drive unit having a plurality of links whose lengths or warps can be individually controlled, and a drive unit that operates like a tongue is provided. I have it.

According to one aspect of the present invention, it is possible to realize a robot arm having a high degree of freedom of movement and less restrictions on movement (for example, movement such as rolling).

FIG. 3 is a perspective view of the robot arm according to the first embodiment of the present invention. FIG. 3 is a circuit diagram showing an equivalent circuit of a link included in the robot arm shown in FIG. 1. It is sectional drawing which shows the muscle structure of a tongue. It is a side view and a top view of a robot arm concerning a 2nd embodiment of the present invention. It is a perspective view of the robot arm which concerns on the 3rd Embodiment of this invention. FIG. 6 is a side view of a link included in the robot arm shown in FIG. 5.

[First Embodiment]
(Structure of robot arm)
The configuration of the robot arm 1 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a perspective view of a robot arm 1 according to this embodiment.

The robot arm 1 is a robot arm (manipulator) imitating a human tongue, and includes a drive unit 11 and a covering unit 12, as shown in FIG. 1. The drive unit 11 is composed of a plurality of links L whose lengths can be individually controlled, and operates like a tongue. The links L adjacent to each other are connected via joints J (for example, ball joints), and the angles formed by the links L connected via the joints J can freely change. The covering portion 12 is made of an elastic material such as rubber and covers the driving portion 11.

The arrangement of the links L in the drive unit 11 is determined based on the wire frame model that expresses the tongue. That is, each link L is arranged so as to correspond to each edge of the wire frame model expressing the tongue.

By changing the length of these links L by remote control, the drive unit 11 can be operated like a tongue. For example, if the link L along the front-rear direction is extended on the lower surface side and the link L along the front-rear direction is contracted on the upper surface side, the robot arm 1 can be rounded so that the side view has a U-shape. Alternatively, by extending the link L along the left-right direction on the lower surface side and contracting the link L along the left-right direction on the upper surface side, the robot arm 1 can be rounded so that the front view shape becomes U-shaped. Alternatively, if the link L along the vertical direction is extended and the link L along the horizontal direction is contracted, the cross section of the robot arm 1 can be rounded and the thickness of the robot arm 1 can be increased.

As described above, according to the present embodiment, it is possible to realize the robot arm 1 having a high degree of freedom of movement and few restrictions on operations.

(Example of link structure)
A configuration example of the link L that constitutes the drive unit 11 of the robot arm 1 will be described with reference to FIG. FIG. 2 is a circuit diagram showing an equivalent circuit of the link L according to the present configuration example.

As shown in FIG. 2, the link L according to this configuration example includes two springs S1 and S2, one damper D, and one power source P. The first spring S1 and the second spring S2 are connected in series. The damper D and the power source P are connected in parallel with the first spring S1. Let L10 be the natural length of the first spring S1, L1 be the length of the first spring S1, L20 be the natural length of the second spring S2, and L2 be the length of the second spring S2. The length Ltotal=L1+L2 is given by the following constraint condition.

k1(L10-L1)+k2(L20-L2)+Fp=Fext.

In the above formula, Fp is the force from the power source P that tries to extend the first spring S1, and Fext is the force applied from the adjacent link L via the joints J at both ends, and the link L will be shortened. Is an external force. Also, k1 is the spring constant of the first spring S1, and k2 is the spring constant of the second spring S2.

By controlling the force Fp under the above constraint conditions, the length Ltotal=L1+L2 of the link L can be controlled. For example, when k1=k2=k, Ltotal can be expressed as Ltotal=L10+L20+(Fp-Fext)/k.

The first spring S1 receives from the damper D a resistance force b×v1 proportional to the time change rate v1=dL1/dt of the length L1. b is the viscosity coefficient of the damper D. This makes the operation of the robot arm 1 smoother.

(Remote control of robot arm)
The robot arm 1 can be remotely controlled using, for example, the tongue of the operator. In this case, for example, sampling points corresponding to the joints J are set on the surface of the tongue of the operator, and the distance between adjacent sampling points (hereinafter referred to as “sampling point interval”) is measured in real time. Then, each link L is controlled to have a length according to the sampling point interval corresponding to the link L. Thereby, the shape of the robot arm 1 can be changed in conjunction with the shape of the tongue of the operator. Here, the real-time measurement of the sampling interval can be realized by, for example, analyzing an image of the tongue taken by a camera installed in the oral cavity of the operator. It can also be realized by covering the tongue of the operator with a sack incorporating a sensor for measuring the sampling point interval.

Note that the correspondence between the sampling point interval and the length of the link L may or may not be linear. Further, the correspondence between the sampling point interval and the length of the link L may be common to all the links L, or may not be the same. When this correspondence is linear and common, the shape of the robot arm 1 can be controlled to be similar to the shape of the tongue of the operator. When the correspondence is non-linear or non-common, the movement of the tongue of the operator can be reflected or complemented in the movement of the robot arm 1.

(Appendix)
In the embodiment, as the wire frame model that expresses the tongue, the wire frame model that uses triangles as cells is adopted, but the wire frame model is not limited to this. That is, as the wire frame model that expresses the tongue, a wire frame model in which an arbitrary polygon is used as a cell can be adopted. Cells having different numbers of vertices (for example, triangular cells and quadrangular cells) may be mixed in one wire frame model. Further, instead of the wire frame model expressing the tongue, a solid model expressing the tongue may be adopted. In this case, a polyhedron such as a tetrahedron becomes a cell. The arrangement of the links L constituting the drive unit 11 so as to correspond to the edges of the solid model is the same as in the case of adopting the wire frame model.

[Second Embodiment]
(Muscular structure of the tongue)
Before going into the description of the second embodiment of the present invention, the muscle structure of the tongue will be described with reference to FIG. FIG. 3 is a sectional view of a human tongue.

The tongue is a muscular organ consisting of multiple muscles (striated muscles). The tongue muscles that make up the tongue are divided into the internal tongue muscles that make up the tongue and the external tongue muscles that support the tongue. The internal tongue muscle is an upper longitudinal tongue muscle that expands and contracts in the anterior-posterior direction on the upper surface of the tongue, a lower longitudinal tongue muscle that expands and contracts in the anterior-posterior direction on the lower surface of the tongue, a lateral tongue muscle that expands and contracts in the lateral direction inside the tongue, It contains vertical tongue muscles that expand and contract in the vertical direction, and is used to deform the tongue. The external tongue muscle includes the genioglossus muscle that draws the tongue body forward, the styloglossus muscle that draws the tongue body backward, and the hyoid hyoid muscle that pulls the tongue body downward, and is used for moving the tongue body.

(Structure of robot arm)
The configuration of the robot arm 2 according to the second embodiment of the present invention will be described with reference to FIG. In FIG. 4, (a) is a side view of the robot arm 2 and (b) is a plan view of the robot arm 2.

The robot arm 2 is a robot arm (manipulator) imitating a human tongue, and includes a drive unit 21 and a covering unit 22, as shown in FIG. 4. The drive unit 21 is composed of a plurality of links L and L′ whose lengths can be individually controlled, and operates like a tongue. The links L and L'adjacent to each other are connected via a joint J (for example, a ball joint), and the angle formed by L and L'connected via each joint J can freely change. The covering portion 22 is made of an elastic material such as rubber and covers the driving portion 21.

The arrangement of the links L and L'in the drive unit 21 is determined based on the arrangement of the tongue muscles forming the tongue. That is, the links L and L'are arranged so as to correspond to the tongue muscles of the tongue. More specifically, the links L and L'constituting the drive unit 21 are roughly classified into a link L corresponding to the internal tongue muscle and a link L'corresponding to the external tongue muscle. The link L corresponding to the internal tongue muscle includes a link L1 corresponding to the superior longitudinal tongue muscle, a link L2 corresponding to the inferior longitudinal tongue muscle, a link L3 corresponding to the transverse tongue muscle, and a link L4 corresponding to the vertical tongue muscle. , Which are used to deform the tongue. The link L'corresponding to the external tongue muscle has a link L'1 corresponding to the genioglossus muscle, a link L'2 corresponding to the stylohyoid muscle, and a link L'3 corresponding to the hyoid hyoid muscle. , These are used to move the tongue.

By changing the lengths of these links L and L'by remote control, the drive part 21 can be operated like a tongue. For example, if the link L2 corresponding to the inferior longitudinal tongue muscle is extended and the link L1 corresponding to the superior longitudinal tongue muscle is contracted, the robot arm 2 can be rounded so that the side view has a U-shape. Alternatively, if the link L3 on the lower surface side corresponding to the lateral tongue muscle is extended and the link L3 on the upper surface side corresponding to the lateral tongue muscle is contracted, the robot arm 2 can be rolled so that the shape in a front view becomes U-shaped. it can. Alternatively, the thickness of the robot arm 2 can be increased by extending the link L4 corresponding to the vertical tongue muscle and contracting the link L3 corresponding to the transverse tongue muscle. Alternatively, the robot arm 2 can be projected forward by extending the link L'2 corresponding to the genioglossus muscle and contracting the link L'1 corresponding to the genioglossus muscle.

As described above, according to the present embodiment, it is possible to realize the robot arm 2 which has a high degree of freedom of movement and has few restrictions on operations.

(Example of link structure)
The links L and L′ forming the drive unit 21 of the robot arm 2 according to the present embodiment can be realized similarly to the link L forming the drive unit 11 of the robot arm 1 according to the first embodiment. Therefore, the illustration and description of the configuration example of the links L and L′ that configure the drive unit 21 of the robot arm 2 according to the present embodiment will be omitted.

(Remote control of robot arm)
The robot arm 2 can be remotely controlled using, for example, the tongue of the operator. In this case, for example, the expansion/contraction state of each tongue muscle of the operator is measured in real time. Then, each link L, L′ is controlled to have a length corresponding to the stretchable state of the tongue muscle corresponding to the link L, L′. Thereby, the shape of the robot arm 2 can be changed in association with the shape of the tongue of the operator.

[Third Embodiment]
(Structure of robot arm)
The configuration of the robot arm 3 according to the third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a perspective view of the robot arm 3.

The robot arm 3 is a robot arm (manipulator) imitating a human tongue, and includes a drive unit 31 and a covering unit 32, as shown in FIG. The drive unit 31 is composed of a plurality of links L capable of individually controlling the warp, and operates like a tongue. The links L adjacent to each other are connected via a joint J (for example, a T-shaped or cross-shaped joint), and the angle formed by the links L connected via each joint J is fixed. The covering portion 32 is made of an elastic material such as rubber and covers the driving portion 31.

The arrangement of the links L in the drive unit 31 is in a vein pattern. That is, the drive unit 31 is configured by the link L1 of the first layer serving as a trunk, the link L2 of the second layer branched from the link L1, and the link L3 of the third layer branched from the link L2.

By changing the warp of these links L by remote control, the drive part 31 can be operated like a tongue. For example, by bending the link L1 of the first layer serving as the trunk upward, the robot arm 3 can be rounded so that the side view has a U shape. Alternatively, the robot arm 3 can be rounded so that the front view has a U-shape by bending the second-layer link L2 serving as a branch upward.

As described above, according to the present embodiment, it is possible to realize the robot arm 3 which has a high degree of freedom of movement and has few restrictions on operations.

(Example of link structure)
A configuration example of the link L that constitutes the drive unit 31 of the robot arm 3 will be described with reference to FIG. 6A and 6B are cross-sectional views of the link L according to the present configuration example.

As shown in FIG. 6, the link L according to this configuration example includes a first metal layer M1 made of a metal having a relatively large coefficient of thermal expansion and a first metal layer M1 made of a metal having a relatively small coefficient of thermal expansion. It is a bimetal strip including two metal layers M2. The link L is arranged such that the first metal layer M1 is located on the lower surface side of the robot arm 3 and the second metal layer M2 is located on the upper surface side of the robot arm 3.

In a room temperature environment, the link L maintains a flat state, as shown in FIG. When the link L is heated, the first metal layer M1 having a relatively large coefficient of thermal expansion expands more than the second metal layer M2 having a relatively small coefficient of thermal expansion. As a result, the link L is warped upward as shown in FIG. On the contrary, in the high temperature environment, the link L maintains the warped state as shown in FIG. When the link L is cooled, the first metal layer M1 having a relatively large coefficient of thermal expansion contracts more than the second metal layer M2 having a relatively small coefficient of thermal expansion. As a result, the link L becomes flat as shown in FIG.

There is a certain correspondence between the degree of warp of the link L (for example, the radius of curvature) and the temperature of the link L. Therefore, by controlling the temperature of the link L, the degree of warpage of the link L can be controlled. The temperature of the link L can be controlled as follows, for example. That is, when the temperature of the link L is lower than the control target value, a current is passed through the link L until the temperature of the link L reaches the control target value, and the temperature of the link L is increased by Joule heat. On the contrary, when the temperature of the link L is higher than the control target value, current is not passed through the link L until the temperature of the link L reaches the control target value, and the temperature of the link L is lowered by natural cooling. Further, as another method of controlling the temperature of the link L, a method of disposing a heater near the link L and controlling the current flowing through the heater may be used.

Further, the link L is not limited to the two-layer structure of the first metal layer M1 and the second metal layer M2 as shown in FIG. 6, and the second metal is sequentially provided from the lower surface side of the robot arm 3. It may have a three-layer structure in which the layer M2, the first metal layer M1, and the second metal layer M2 are arranged. In the link L having such a three-layer structure, by selectively heating the second metal layer M2 located on the lower surface side of the robot arm 3 or the second metal layer M2 located on the upper surface side of the robot arm 3. , The direction in which the link L is bent can be selected.

The link L is not limited to the bimetal strip as long as the warp can be controlled. For example, the link L may be realized by using a shape memory alloy.

[Summary]
A robot arm according to aspect 1 of the present invention is a drive unit having a plurality of links whose lengths or warps can be individually controlled, and is characterized by including a drive unit that operates like a tongue.

According to the above configuration, it is possible to realize a robot arm that has a high degree of freedom of movement and has less restrictions on operation, as compared with a conventional robot arm. The operation of the robot arm configured as described above is performed, for example, by rounding so that the side view shape or the front view shape becomes a U shape, which cannot be realized by the robot arm described in Patent Document 1. It also includes actions.

A robot arm according to a second aspect of the present invention is the robot arm according to the first aspect of the present invention, wherein the links are arranged so as to correspond to respective edges of a wire frame model or a solid model expressing a tongue. The drive unit operates by changing the length of the link.

According to the above configuration, it is possible to realize a robot arm having a high degree of freedom of movement and a small number of movement restrictions by using a link whose length can be controlled. Further, when the links are arranged so as to correspond to the respective edges of the wire frame model expressing the tongue, (1) a sampling point corresponding to a node of the wire frame is set on the operator's tongue, and (2) By measuring the distance between adjacent sampling points in real time, and (3) controlling the length of each link to the length corresponding to the distance between the corresponding sampling, it is as if the tongue of the operator were externalized. It is possible to realize a robot arm that behaves like a robot.

A robot arm according to a third aspect of the present invention is the robot arm according to the first aspect of the present invention, wherein the link is arranged so as to correspond to each of the tongue muscles forming the tongue, and the drive unit includes the link. It operates by changing the length of.

According to the above configuration, it is possible to realize a robot arm having a high degree of freedom of movement and a small number of movement restrictions by using a link whose length can be controlled. In addition, (1) by measuring the contraction state of each tongue muscle composing the operator's tongue, (2) controlling the length of each link to a length corresponding to the contraction state of the corresponding tongue muscle, It is possible to realize a robot arm that behaves as if the operator's tongue was externalized.

A robot arm according to aspect 4 of the present invention is the robot arm according to aspect 1 of the present invention, in which the links are arranged in a vein pattern, and the drive section operates by changing a warp of the link. , Is characterized.

According to the above configuration, it is possible to realize a robot arm that has a high degree of freedom of movement and has few restrictions on movement by using a link (for example, a bimetal strip) whose warp can be controlled.

The drive unit included in the robot arm according to the second aspect of the present invention can be operated like a tongue or an object other than the tongue. A robot arm equipped with a drive unit such as the latter is "a plurality of links whose lengths can be individually controlled so that each edge of a wire frame model or a solid model expressing an arbitrary object can be handled. It can be described as a “robot arm with a drive having a plurality of links arranged”. With such a configuration as well, it is possible to realize a robot arm that is more flexible in operation than the conventional robot arm.

Further, the drive unit included in the robot arm according to the fourth aspect of the present invention can be operated like a tongue or an object other than the tongue. A robot arm provided with a drive unit such as the latter is expressed as "a robot arm provided with a drive unit having a plurality of links capable of individually controlling the warp and having a plurality of links arranged in a vein pattern". be able to. With such a configuration as well, it is possible to realize a robot arm that is more flexible in operation than the conventional robot arm.

[Appendix]
The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

1,2,3 Robot arm 11,21,31 Drive part 12,22,32 Cover part L,L' link

Claims (4)

A drive unit having a plurality of links capable of individually controlling length or warpage, the drive unit operating like a tongue,
A robot arm characterized by that. The link is arranged so as to correspond to each edge of the wire frame model or the solid model expressing the tongue, and the drive unit operates by changing the length of the link.
The robot arm according to claim 1, wherein: The link is arranged so as to correspond to each tongue muscle forming the tongue, and the drive unit operates by changing the length of the link,
The robot arm according to claim 1, wherein: The link is arranged in a vein pattern, the drive unit operates by changing the warp of the link,
The robot arm according to claim 1, wherein:

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