JP7017234B2 - A mesh robot consisting of a small robot and a small robot - Google Patents

Description

The present disclosure relates to a small robot having a cell function and an aggregate thereof, which is a mesh type robot, which forms a three-dimensional form, particularly a curved surface.

A so-called modular robot, in which the form of an aggregate changes when a plurality of small robots move or are connected / separated from each other, has been proposed for a long time. On the other hand, research is also underway to study changes associated with the development of living organisms as morphological changes in the natural world and apply them to robots in the future. For example, many researchers are interested in the fact that many organisms form complex and diverse morphologies from the state of the spherical shell (blastulation) without the need for arbitrary external forces.

In addition, there is morphogenesis consisting of complex folding of a single layer of epithelial sheet such as beetle horns, and research has been conducted from both experimental and simulation perspectives to clarify this principle (Non-Patent Document 1). In particular, recent research results using a three-dimensional model of an epithelial sheet have revealed that cell apical surface contraction, cell elongation and migration, basal plane elasticity and viscosity, etc. are important (Non-Patent Document 2). ).

Further, in discrete differential geometry in the field of mathematics, the Circle Packing Mesh (CPM) theory (Non-Patent Document 4) proposed by Schiftner et al. Is known as a method for constructing a circular mesh based on a triangular mesh.

On the other hand, as a modular robot, for example, there is an example in which each small robot has a rotary actuator and a connecting mechanism, and a plurality of small robots are connected to each other to realize an arbitrary shape and movement (Patent Document). 1. Patent Document 2). Further, a modular robot capable of approximately forming an arbitrary curved surface shape by connecting small robots provided with rotary actuators on all three sides of an equilateral triangle like origami has been proposed (Non-Patent Document 3).

Japanese Patent Application Laid-Open No. 2003-103063 U.S. Patent US65688869

M. Imai et al. "Three-dimensional morphogenesis of MDCK cells induced by contractible conforms on a viscous substrate", Scientific Reports, 2015. S. Okuda et al. , "Apical controllity in growing epithelium supports robot maintenance of smoth curvatures against cell-division-induced mechanical." Biomech. , 2013. C. H. Belke and J. Paik, “Mori: A Modular Origami Robot”, Trans. Mechatronics, 2017. A. Schiftner et al. , “Packing circles and surfaces on surfaces”, Proc. of ACM SIGGRAPH, 2009.

However, in the techniques of Patent Documents 1 and 2, the actuator operation of each small robot is limited to uniaxial rotation, and the small robot can be expanded only in one dimension via the actuator, so that it is a feasible modular robot. However, it had to be a so-called snake type or a combination of multiple snake types.

Further, the technique of Non-Patent Document 3 has two-dimensional expandability, but the lengths of all the sides of the triangle are fixed, so that the feasible shape is limited. If each side is arbitrarily changed, the triangle can form any curved surface as seen in the FEM analysis. However, even if such a triangular robot whose length can be changed independently on three sides can be realized, it is inevitable that the structure will be very complicated.

Furthermore, when considering application to medical use, for example, an exclusion device that changes its shape according to the shape of internal organs during surgery, there is a high possibility that the triangular mesh will damage the organs due to the corners of the apex. Occurs. Therefore, the present inventors have conducted diligent studies in order to solve the above-mentioned problems, and have come to find new findings.

The small robot according to the present invention has an approximate disk shape, and is provided on the outer circumference of an expansion / contraction type actuator that changes the diameter of the approximate disk shape and the expansion / contraction type actuator, and has an entire circumference according to the change in the diameter. Includes an approximately annular telescopic joint that expands and contracts and is evenly or uniformly provided with coupling members.

The approximate disk shape may be an axisymmetric shape or a rotationally symmetric shape having an octagon or more.

The expansion / contraction type actuator may change the diameter of the approximate disk shape by air pressure.

The coupling member in the telescopic coupling portion may be a permanent magnet provided so as to be rotatable.

The telescopic joint portion may be formed by connecting the plurality of connecting members with an elastic body.

Each of the small robots according to the present invention has an approximate disk shape, and is provided on the outer periphery of the expansion / contraction type actuator that changes the diameter of the approximate disk shape and the expansion / contraction type actuator. A plurality of small robot units are fixed at the center of each, including an approximately annular telescopic joint portion whose circumference is expanded and contracted and whose coupling member is evenly or uniformly provided.

The mesh-type robot according to the present invention is a mesh-type robot in which a plurality of the small robots are assembled, and each of the small robots is coupled to another small robot via each telescopic joint.

According to the present invention, it can be realized with an extremely simple structure, and by further gathering, it is possible to realize a robot that forms a curved surface while keeping a cavity inside.

Configuration diagram of a small robot according to an embodiment of the present invention An operation explanatory view of a mesh type robot in which the small robots of FIG. 1 are gathered. Conceptual diagram showing the state of each small robot in FIG. Conceptual diagram showing input / output of mesh type robot Configuration diagram of the expansion / contraction type actuator in the first embodiment Configuration diagram of the expansion / contraction type actuator in the second embodiment Conceptual diagram of the telescopic joint portion in Example 3 Conceptual diagram of the telescopic joint portion in Example 4 A perspective view and a top view of the small robot according to the fifth embodiment. Sectional drawing of the small robot in Example 6 External view of the mesh type robot in Example 6 Explanatory drawing which shows the design method of the mesh type robot in Example 7. Initial placement generation result of the mesh type robot in Example 7

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows a conceptual diagram of a small robot according to an embodiment of the present invention (hereinafter referred to as the present embodiment). In FIG. 1, the small robot 100 has an approximate disk shape, and is composed of a power supply unit 11, an expansion / contraction type actuator 1 on the outside thereof, and an expansion / contraction type coupling unit 2 provided on the outer periphery of the expansion / contraction type actuator 1. It is composed.

In the present invention, the approximate disk shape represents an approximately circular flat shape or a cylindrical shape, and the approximately circular shape represents an axisymmetric shape or a rotation target shape having eight or more angles (for example, a regular octagonal pillar shape). Further, the surface of the small robot 100 may include fine irregularities. Further, in the case of a regular polygonal prism, the length of each side may vary by about 10%.

The expansion / contraction type actuator 1 changes the diameter of the approximate disk shape of the small robot 100. The method for changing the diameter is not particularly limited, and an electromagnetic method, an electrochemical method, a physical method such as hydraulic pressure or pneumatic pressure may be used. Further, a shape memory alloy may be used. A specific configuration using air pressure will be described in Examples described later. The method of supplying air pressure is not particularly limited, and may be supplied from the outside via the power supply unit 11. The power supply unit 11 has a built-in micro pump and is supplied by this pump. May be. Further, the pressure may be changed by a chemical reaction.

As an electrochemical method, for example, there is a method of applying an electric field to a dielectric polymer material to cause bending deformation or creep deformation. As the dielectric polymer material, polyvinyl chloride (PVC), polymethyl methacrylate, polyurethane, polystyrene, polyvinyl acetate, nylon 6, polyvinyl alcohol, polyvinyl carbonate, polyethylene terephthalate, polyacrylonitrile, silicone rubber and the like can be used.

The telescopic coupling portion 2 is provided on the outer periphery of the expansion / contraction type actuator 1 and has an annular shape whose entire circumference expands and contracts according to a change in the diameter of the actuator. Further, the telescopic joint portion 2 may be elastically deformed not only in the circumferential direction but also in the radial direction. This function is useful for stably approximating a curved surface using multiple small robots.

Further, the telescopic joint portion 2 is provided with the coupling member 21 evenly or uniformly. These coupling members are not particularly limited, and any method such as a magnetic method, an electrical method, a chemical method, and a mechanical method may be adopted. As a chemical method, for example, a weak viscous re-peelable (most stickable) type adhesive may be uniformly applied on the outer peripheral surface. As the magnetic method, a permanent magnet or an electromagnet may be used, but a method using a permanent magnet will be described in Examples described later, including a method for realizing elasticity.

The power supply unit 11 supplies a power source, that is, power for executing the expansion / contraction operation to the expansion / contraction type actuator 1. In the case of air pressure, a built-in pump may be provided as described above, or a valve for controlling the air pressure supplied from the outside may be provided. In the case of electric energy, it may be a built-in battery or may be a relay of supply from an external power source using a wired or wireless system. Further, the power supply unit 11 may be provided with a communication means for transmitting and receiving information such as sensor information and target values necessary for controlling the robot to and from another robot or a computer that controls a plurality of robots in a centralized manner. .. The supply of power from the outside and the transmission and reception of information will be described later.

The size of the small robot 100 is not particularly limited, but may be about 5 mm to 100 mm in the neutral state. The thickness may be about 1 mm to 100 mm. The larger the range of expansion and contraction, the better, but it is preferable that the maximum radius changes up to about twice the minimum radius.

FIG. 2 shows a state when a plurality of small robots 100 are assembled. In FIG. 2, each small robot (100) is coupled to another small robot (100') via each telescopic coupling portion 2. In particular, the coupling member 21 made of a permanent magnet or the like acts directly on the coupling.

Further, as shown in FIG. 2, each small robot 100 performs an expansion or contraction operation while being in contact with another small robot 100'. At this time, the contacts of each other slide appropriately. As a result, any three-dimensional curved surface can be approximately formed based on the CPM theory (Non-Patent Document 4). Further, it is also possible to change the three-dimensional curved surface by once forming the three-dimensional curved surface and then expanding / contracting one or a plurality of small robots at appropriate parts.

When the coupling members 21 such as magnets are evenly arranged on the telescopic coupling portion 2, the contacts between the small robots in contact with each other do not slide continuously but are displaced discretely. For example, in the regular dodecagonal (when reduced) small robot of the embodiment described later, two connecting members 21 per side, a total of 24 connecting members 21, are arranged so as to be evenly spaced at the maximum radius, and are 15 degrees (circle). The contacts can be changed with an accuracy of 1/24) of the circumference. Even if there is only one connecting member per side, the more polygonal it is (for example, a 36-sided polygon), the higher the accuracy (in 10-degree increments).

However, if each connecting member 21 is connected by an elastic body (22) as in the embodiment described later, even if there is some error between the positions of the adjacent small robot and the connecting member 21, they are attracted to each other. Each elastic body is deformed. As a result, the permanent magnets of the coupling member 21 can be reliably coupled to each other, although the arrangement is slightly deviated from the uniform arrangement.

In each small robot 100 forming an aggregate, the situation in which it is currently placed is, as shown in FIG. 3, the angle of contact between its own radius r and another robot 100'(θ ₁ , θ ₂ ). , ・ ・ It is determined by the polar coordinates consisting of θ _n ). In other words, by aggregating the polar coordinates of the contacts of all the small robots, it is possible to identify the current overall picture of the aggregate formed by these robots. If the difference between the overall image of the aggregate and the desired overall image (reference curved surface) is obtained and feedback is applied so that the difference is reduced, the aggregate of the small robot can be brought closer to the desired overall image.

FIG. 4 shows a conceptual diagram of input / output for each small robot. In FIG. 4, 110 represents an input line and 111 represents an output line. Here, it is assumed that each small robot is distinguished by id. A power source for expansion or contraction is supplied to each small robot through the input line 110. Further, the coordinate information (r, θ ₁ , θ ₂ , ... θ _n ) of the position where each small robot is in contact with the surrounding small robots is returned through the output line 111 together with the id information.

The input line 110 may be wired or wireless. In the case of a wire, it may be a conductor that supplies electricity as a power source, or it may be a pipe that supplies air pressure. When the power source to be supplied is pneumatic, the amount of supply required differs depending on the robot, but it can be individually adjusted by providing a micro valve or the like at the entrance of each small robot 100 identified by id. At this time, it is necessary to transmit the information instructing the opening / closing of the microvalve together with the id information through the input line 110. In the case of pneumatic use, this information may be transmitted through a lead wire in the pipe.

The output line 111 transmits only an electric signal and may be either wired or wireless. In the case of a wired wire, a conducting wire may be used, and further, it may be shared with the conducting wire of the input line 110. In this case, in order to avoid interference of each signal, channels may be assigned in advance so that they can be separated on the frequency axis or the time axis. Further, when the input line 110 is composed of only conductors as described above, the input line 110 and the output line 111 may be further combined and realized by one conductor.

Although the input line 110 and the output line 111 are connected to each small robot 100, when input / output is realized by one lead wire or one pipe having a built-in lead wire, each small robot 100 is connected by the lead wire or the pipe. It may be connected in a row in a bead shape. Alternatively, the conductors or pipes may be assembled in a grid pattern, and the small robot 100 may be connected to each intersection.

Hereinafter, examples of the present invention will be described.
(Example 1)
First, as a specific example of the small robot 100 in the present invention, an expansion / contraction type actuator 1 that utilizes pneumatic pressure will be described with reference to FIG.

In FIG. 5, the expansion / contraction type actuator 1 is composed of an annular elastic tube 12, 13 and 14, and elastic tubes 15 and 16 provided radially through the elastic tubes 12, 13 and 14, respectively. The power supply unit 11 supplies air (pneumatic pressure) to the annular elastic tubes 12, 13 and 14 via the elastic tubes 15 and 16. The circumference of the annular elastic tubes 12, 13, and 14 to which air pressure is supplied expands and contracts according to the pressure, and the diameter of the expansion and contraction type actuator 1 also expands and contracts accordingly.

When air pressure is used, it is preferable that the air pressure acts only on expansion and contraction in the radial direction and the circumferential direction, but since the pressure acts isotropically in the elastic tube, it changes slightly in the thickness direction. Therefore, instead of the elastic tube, an expansion / contraction type actuator 1 using a sheet having spiral creases as shown in the next embodiment may be used.

(Example 2)
In FIG. 6, the sheet 17 in the expansion / contraction type actuator 1 has a spiral crease. In the figure, the solid line represents the mountain fold and the dotted line represents the valley fold. When two such sheets 17 are sealed between the outer peripheral portions and the inner peripheral sides, and air pressure is applied inside, a force acts in the direction of extending the crease, and the shape changes so that the spiral becomes close to a straight line. As a result, the radius of the (bonded) sheet 17 is increased. The power supply unit 11 may be provided so as to be sandwiched between the two sheets 17. This spiral crease sheet has an excellent feature that the dynamic range of the maximum and minimum radii is very wide, and the dynamic range does not widen in the thickness direction.

(Example 3)
FIG. 7 shows an example of the telescopic coupling portion 2 in the small robot 100 according to the present invention. In FIG. 7, the telescopic connecting portion 2 (only a part of the annular structure is displayed) is composed of a plurality of connecting members 21 and an elastic body 22 connecting them. Further, a permanent magnet is rotatably provided on each coupling member 21.

In FIG. 7, 2'represents a part of another small robot (100') in contact with the small robot (100). Permanent magnets in the respective coupling members near the contact points of one small robot (100) and the other small robot (100') rotate so as to have opposite polarities, attract each other, and join.

The elastic body 22 is not particularly limited as long as it can expand and contract according to the expansion and contraction of the expansion / contraction type actuator 1, and may be a resin-based product such as silicone rubber or a metal processed product such as a coil spring. More preferably, a foldable frame as shown in the following embodiment may be used.

(Example 4)
FIG. 8 shows another embodiment of the telescopic coupling portion 2 in the small robot 100 according to the present invention. In FIG. 8, each connecting member 21 is connected substantially evenly by an elastic body 23 having a foldable frame shape. As a connecting method, the same number of independent elastic bodies 23 as the connecting members 21 may be connected alternately to form the annular telescopic joint portion 2, or the elastic body may be folded. After connecting the portions other than the portions with a straight line or a flat surface and integrally molding them into an annular shape, the connecting member 21 may be fixed to the portions other than the folded portions by a method such as adhesion. The latter will be described in the next embodiment.

(Example 5)
FIG. 9 is a perspective view (left) and a top view (right) of an embodiment of the small robot 100 according to the present invention, which is characterized in that an elastic body 23 having a foldable frame shape is integrally molded. In this embodiment, the small robot (100) has a flat shape of a regular dodecagon (when reduced), and the shape of the outer periphery thereof is particularly determined by the shape of the telescopic joint portion 2.

As shown in FIG. 9, in the elastic body 23, a foldable frame portion and a basket-shaped frame connecting the foldable frame portion are integrally molded in an annular shape. The material of the elastic body 23 is not particularly limited as long as it has a property of elastically deforming, and may be rubber, resin, or a leaf spring. In this embodiment, one pair (two) of permanent magnets constituting the coupling member 21 is fixed to both ends of the cage-shaped frame. If the elastic body 23 is integrally molded in this way, the telescopic joint portion 2 can be manufactured at a lower cost.

In this embodiment, a pair of magnets are arranged at both ends of the cage-shaped frame, but due to this configuration, when the expansion / contraction type actuator 1 contracts to the minimum radius, it is close to (almost integrated) with the magnets of the adjacent frame. ), Therefore, it is substantially equivalent to arranging 12 magnets per circumference. On the other hand, when the expansion / contraction type actuator 1 expands to the maximum radius, the foldable frame portion of the elastic body 23 is fully extended, so that the space between the elastic body 23 and the adjacent frame is widened and the magnet functions as 24 magnets per circumference.

(Example 6)
FIG. 10 shows a cross-sectional view of a small robot in which two small robot units 100a and 100b are fixed at their respective centers. Each robot unit has an expansion / contraction type actuator 1a, 1b and an expansion / contraction type coupling portion 2a, 2b, and the expansion / contraction type actuators 1a, 1b operate independently. This configuration makes it even easier to collect a plurality of small robots to form a curved surface. The power supply units 11a and 11b in each of the small robots have a fixed shape, and these may be bonded together or integrally molded. Further, the entire two small robot units may be integrally molded. Further, the number of small robot units is not limited to two, and a plurality of small robot units may be fixed at the center.

For example, as shown in FIG. 11, when forming curved surfaces having various radii of curvature (R), the radius difference between the small robot units 100a and 100b is small for a place where R is large, and the place where R is small. On the other hand, by increasing the radius difference between the small robot units 100a and 100b, the target curved surface can be formed more stably.

(Example 7)
In this embodiment, a specific method for constructing a mesh-type robot, particularly a method for obtaining the radius and contact points of each robot when an arbitrary curved surface is filled with a plurality of small robots will be described. First, the target reference curved surface is set. Next, an arbitrary number of points on the song are acquired, and the point cloud is used as a quadrilateral vertex group to form a quadrilateral mesh. Next, draw a diagonal line to generate a triangular mesh. At this time, the diagonal lines should be staggered. After that, a circle inscribed in each triangle (E ₁ E ₂ E ₃ in FIG. 12) is arranged to obtain a CPM (circle packing mesh). At this point, the small robots adjacent to each other are not in direct contact with each other ((100) and (100') in FIG. 12).

Non-linear optimization processing by the Levenberg-Marquardt method is performed on this model. In this optimization, a total of two parameters are used, a parameter for bringing the internal contacts closer to each other and a parameter for bringing the reference curved surface and the CPM closer to each other. The coordinates of the triangle vertex group are updated so that the value obtained by multiplying these two parameters by the weighting coefficients and adding them to the minimum is minimized. With these two parameters, it is possible to optimize the internal contacts so that they are close to each other but not too far from the reference curved surface.

(simulation)
A simulator was created using the graphic library OpenGL according to the above procedure. First, the target value was a quadratic Bezier curve as shown in FIG. 10, and a quadrilateral mesh with 14 columns horizontally and 18 rows vertically was generated. A total of 504 inscribed circles (small robots) were placed diagonally to this, and optimization was performed with this as the initial state.

The result of the optimization is shown in FIG. It was shown that a group of 504 small robots converged on a quaternary Bezier curved shape. As described above, an arbitrary curved surface can be formed by optimizing the radius of each small robot 100 and the contact position with the adjacent robot for each target value.

ここで、Ｍ∈Ｒ^３×３は質量ｍを単位行列にかけたものを、Ｊ∈Ｒ^３×３は慣性テンソルを、ｐ”∈Ｒ^３はpを位置としたときの加速度を、θ”∈Ｒ^３はθを各軸周りの角度としたときの角加速度を、Ｆ∈Ｒ^３は外力のベクトルを、Ｎ∈Ｒ^３は回転モーメントを、それぞれ表す。 The concept of adding a mechanical element to this curved surface will be described below. First, if each small robot is a rigid circle, the equation of motion can be written as follows.

Here, M ∈ R ^{3 × 3} is the mass m multiplied by the unit matrix, J ∈ R ^{3 × 3} is the moment of inertia tensor, and p ″ ∈ R ³ is the acceleration when p is the position, θ ”∈. R ³ represents the angular acceleration when θ is the angle around each axis, F ∈ R ³ represents the vector of the external force, and N ∈ R ³ represents the rotational moment.

The equation (1) is combined with the number of small robots 100 to obtain the acceleration and angular acceleration of each circle. In order to obtain CPM, optimization is performed so that adjacent inner contacts (contact points between circles and triangles) come into direct contact with each other, but it is considered that there is no solution in which the inner contacts completely contact each other. That is, if the two circles (small robots) are not in contact with each other, no force is generated, and contact occurs only when the two circles (small robots) are out of contact with each other.

Therefore, as one way of thinking, the radius amplification amount Δr when the small robot 100 is expanded is set, and the amount of entanglement between the enlarged circles is considered (FIG. 11). Δr is inversely proportional to the magnitude of the radius. That is, the position where the force is applied is the intermediate point of the distance where the circles overlap on the sides E _1, E _{2, and} E ₃ of the triangle in FIG. The force ^ f'i ( _i = 1-3) from the adjacent circle and the force ^ f " _i from the reference circle are applied here. Therefore, the external force applied to the reference circle is the reaction force of ^ _f'i and ^ f" _i . It becomes the resultant force, and the repulsive force is applied from a maximum of three directions in the same way on other sides. This is a case where the circles are sunk into each other, and when they are separated from each other, a force based on the property of being used as the telescopic joint portion 2 acts. In particular, when the magnetic method is adopted, the attractive force by the magnet works.

The present invention can be used as a simulator for expressing the function of cells. In addition, the knowledge of conventional 3D morphogenesis and mechanobiology can be observed by robots, and empirical research of new mathematical models becomes possible. Further, the present invention is expected to develop as a medical robot for exclusion in minimally invasive surgery because a small robot can invade from a narrow entrance and form a mesh type having an arbitrary shape in an internal space. Specifically, it can be used as a robot that secures a workable area for the hand of forceps in endoscopic surgery. It can also be used as a robot for virtual reality.

1 Expansion / contraction type actuator 2 Expansion / contraction type joint part 11 Power supply part 12-14 Elastic tube 17 Sheet 21 Coupling member 22 Elastic body 23 Elastic body 100 Small robot

Claims (7)

An expansion / contraction type actuator having an approximate disk shape and changing the diameter of the approximate disk shape, and an expansion / contraction type actuator provided on the outer circumference of the expansion / contraction type actuator, the entire circumference expands and contracts according to the change in the diameter, and evenly or A small robot that includes an approximately annular telescopic joint with uniform coupling members. The small robot according to claim 1, wherein the approximate disk shape is an axisymmetric shape or a rotationally symmetric shape having an octagon or more. The small robot according to claim 1 or 2, wherein the expansion / contraction type actuator changes the diameter of the approximate disk shape by air pressure. The small robot according to claim 1, wherein the coupling member in the telescopic coupling portion is a permanent magnet provided so as to be rotatable. The small robot according to claim 1, wherein the telescopic joint portion is formed by connecting the plurality of connecting members by an elastic body. Each has an approximate disk shape and is provided on the outer periphery of the expansion / contraction type actuator that changes the diameter of the approximate disk shape and the expansion / contraction type actuator. Alternatively, a small robot in which a plurality of small robot units including an generally annular telescopic joint portion provided with uniformly connecting members are fixed at the center of each. A mesh-type robot in which a plurality of small robots according to claim 1 or 6 are assembled, and each of the small robots is connected to another small robot via each telescopic joint. ..

Images