Spatial distribution type multistable flexible mechanism and stable state construction method thereof

Abstract

The invention provides a spatially distributed multistable flexible mechanism and a steady-state construction method thereof. The mechanism comprises a flexible beam group, a regular polyhedron outer frame and a central body, the regular polyhedron outer frame is of a rigid structure. The center body is located in the center of the regular polyhedron outer frame. The flexible beam group comprises a plurality of flexible beams; the far center end of each flexible beam is connected to each inner vertex of the regular polyhedron outer frame, and the near center end of each flexible beam is connected to the center body; each steady state of the mechanism is a stable posture achieved after the center body is twisted under the interaction of all the flexible beams when axial displacement preloads are applied to the far center ends of all the flexible beams to cause the flexible beams to bend. The number of the constructed multistable states is greatly increased, the spatial distribution type organization relation is achieved, each stable state and each stable state conversion path can be used for data storage and expression, the information expression ability is improved, and the stable state conversion paths can serve as basic logic structure units to be used for mechanical calculation so as to exponentially improve the information processing and operation ability of mechanical calculation.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible mechanisms, and in particular to a spatially distributed multi-stable flexible mechanism and a stable construction method thereof. Background Art

[0002] A flexible mechanism (also called a compliant mechanism) is a new type of assembly-free mechanism that uses flexible elements to transmit motion, force or energy, such as hunting bows, nail clippers, tweezers, etc.

[0003] Multistable flexible mechanisms are a special type of flexible mechanism that can stabilize in multiple equilibrium positions within a certain range of motion and maintain steady state without the need for additional energy consumption. Multistable flexible mechanisms are often used in mechanical systems to act as switches, valves and other components. They have the advantages of a small number of parts, short assembly time and streamlined manufacturing process, which can significantly reduce costs. In addition to being used in the field of mechanical structures, in recent years they have also shown great application prospects in the fields of intelligent robots, energy harvesting, micro-electromechanical systems and so on.

[0004] At present, the design of multi-stable flexible mechanisms often takes the simplest bistable flexible mechanism as the basic structural unit, and realizes the multi-stable flexible mechanism through mutual coupling connection. This multi-stable flexible mechanism designed based on the traditional coupling method often has the disadvantage of limited number of stable states. In addition, the organizational relationship between the stable states of the multi-stable flexible mechanism designed by the traditional coupling method is often linear, that is, the transformation path between the stable states is fixed, such as Figure 2 As shown, it is difficult to achieve a larger number of stable states and richer and more flexible multi-stable organizational relationships through this structural design method, which limits its application value. Summary of the invention

[0005] The present invention provides a spatially distributed multi-stable flexible mechanism to solve the deficiencies of the flexible mechanism in the prior art, such as the limited number of stable states and the single stable state organizational relationship, to achieve a larger number of stable states and a distributed organizational relationship between multiple stable states, thereby broadening the application space of the multi-stable flexible mechanism.

[0006] The present invention provides a spatially distributed multi-stable flexible mechanism, characterized in that it comprises: a flexible beam group, a regular polyhedron outer frame and a central body; wherein:

[0007] The regular polyhedron outer frame is a rigid structure; The central body is located at the center of the regular polyhedron outer frame; The flexible beam group includes a plurality of flexible beams; the distal end of each flexible beam is respectively connected to each inner vertex of the regular polyhedron outer frame, and the proximal end of each flexible beam is connected to the central body; Each stable state of the spatially distributed multi-stable flexible mechanism is a stable posture achieved after the central body is twisted under the interaction of all flexible beams when equal axial displacement preloads are applied to the far-center ends of each flexible beam to cause each flexible beam to buckle.

[0008] According to the spatially distributed multi-stable flexible mechanism provided by the present invention, the flexible beam has a circular cross-section and is isotropic in each bending direction; the geometric parameters of each flexible beam in the flexible beam group are the same; the geometric parameters include the diameter of the cross-section of the flexible beam, the length of the flexible beam, and the magnitude of the axial displacement preload applied to the far center end of the flexible beam.

[0009] According to the spatially distributed multi-stable flexible mechanism provided by the present invention, the torsion direction of the central body during torsion is the positive direction of the normal line around a face of the regular polyhedron outer frame; wherein the positive direction of the normal line is a direction perpendicular to the face and pointing outward with the center as the origin; and the torsion angle of the central body is positively correlated with the magnitude of the axial displacement preload applied to the flexible beam.

[0010] According to the spatially distributed multi-stable flexible mechanism provided by the present invention, the stable states of the spatially distributed multi-stable flexible mechanism correspond one-to-one to the faces of the regular polyhedron outer frame; the central body can transform from the current stable state to the stable state corresponding to any adjacent face of the current corresponding face.

[0011] According to the spatially distributed multi-stable flexible mechanism provided by the present invention, the regular polyhedron outer frame is any one of a regular tetrahedron outer frame, a regular hexahedron outer frame, a regular octahedron outer frame, a regular dodecahedron outer frame and a regular icosahedron outer frame.

[0012] According to the spatially distributed multi-stable flexible mechanism provided by the present invention, the spatially distributed multi-stable flexible mechanism using the outer frame of a regular hexahedron can realize a distributed six-stable state, the spatially distributed multi-stable flexible mechanism using the outer frame of a regular octahedron can realize a distributed eight-stable state, the spatially distributed multi-stable flexible mechanism using the outer frame of a regular dodecahedron can realize a distributed twelve-stable state, and the spatially distributed multi-stable flexible mechanism using the outer frame of a regular icosahedron can realize a distributed twenty-stable state; the spatially distributed multi-stable flexible mechanism using the outer frame of a regular tetrahedron is a special case, and each face corresponds to two stable states rotating clockwise and counterclockwise around the normal of the face respectively. Therefore, the spatially distributed multi-stable flexible mechanism using the outer frame of a regular tetrahedron can realize a total of distributed eight-stable states.

[0013] According to the spatially distributed multi-stable flexible mechanism provided by the present invention, the multiple stable states of the spatially distributed multi-stable flexible mechanism present a spatially uniform distribution characteristic, and the stable states have a distributed organizational relationship.

[0014] The present invention also provides a stable construction method, which is applied to the spatially distributed multi-stable flexible mechanism as described above, and the method comprises: An equidistant axial displacement preload is applied to the far center end of the flexible beam group, so that when the flexible beam group is buckled, the central body is stabilized in a new steady state in a posture twisted by a certain angle under the interaction of all the flexible beams.

[0015] According to a steady-state construction method provided by the present invention, applying an equidistant axial displacement preload to the far center end of the flexible beam group includes: Using a linear displacement motor to apply an axial displacement preload of equal distance along the axis direction to the far center end of the flexible beam group; or,

[0016] Shortening all sides of the regular polyhedron outer frame at equal distances to achieve applying an axial displacement preload of equal distances to the far center end of the flexible beam group; or,

[0017] The actual length of the flexible beam is increased so that the actual length of the flexible beam is greater than the distance between the central body and the inner vertices of the regular polyhedron outer frame.

[0018] The present invention also provides a stable state construction method, which is applied to the spatially distributed multi-stable flexible mechanism as described above, characterized in that the method comprises: applying a force to the central body so that the central body is stabilized in a new stable state after being twisted by a certain angle, thereby realizing the stable state conversion between the multi-stable states with distributed organizational relationships; or,

[0019] The bending direction of any flexible beam in the flexible beam group is changed so that the central body is twisted by a certain angle under the interaction of the multiple flexible beams, and the posture after being twisted by a certain angle is stabilized in a new steady state, thereby realizing the steady state conversion between multiple stable states with distributed organizational relationships.

[0020] The present invention provides a spatially distributed multi-stable flexible mechanism, comprising: a flexible beam group, a regular polyhedron outer frame and a central body; wherein the regular polyhedron outer frame is a rigid structure with good overall rigidity; the central body is located at the center of the regular polyhedron outer frame; the distal ends of each flexible beam are respectively connected to the respective inner vertices of the regular polyhedron outer frame, and the proximal ends of each flexible beam (1) are connected to the central body; each stable state of the spatially distributed multi-stable flexible mechanism is a stable posture achieved after the central body is twisted under the interaction of all flexible beams when equal axial displacement preloads are applied to the distal ends of each flexible beam to cause each flexible beam to buckle.

[0021] The spatially distributed multi-stable flexible mechanism places the central body at the center of the regular polyhedron outer frame and is connected by a flexible beam group. When the flexible beam group buckles, the central body twists a certain angle under the interaction of each flexible beam and reaches the next steady state from the current steady state. Since the central body is placed inside the regular polyhedron outer frame and the spatially distributed multi-stable flexible mechanism has a strictly symmetrical structure, the central body can reach an equivalent state when rotating along any coordinate axis (where the coordinate axis is a direction perpendicular to any face of the regular polyhedron from the center and pointing outward). Therefore, the central body can have the same number of stable states as the regular polyhedron, which significantly increases the number of stable states of the multi-stable flexible mechanism. Since the directions of the coordinate axes of each face are different in three-dimensional space, these stable states are spatially uniformly distributed (different from the multi-stable state of the planar state), and there is a distributed organizational relationship between the multi-stable states, which can realize the planning and editing of the stable state transformation path. Each stable state and the stable state transformation path can be used for data storage and expression, and can be used as a basic logical structure unit for mechanical computing to exponentially improve the information processing and computing capabilities of mechanical computing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is one of the structural schematic diagrams of the spatially distributed multi-stable flexible mechanism provided by the present invention.

[0024] Figure 2 It is a schematic diagram of the principle of steady-state transition between general multi-stable states.

[0025] Figure 3 It is a schematic diagram of the working principle of the spatially distributed multi-stable flexible mechanism provided by the present invention.

[0026] Figure 4 It is one of the steady-state schematic diagrams of a spatially distributed hexastable flexible mechanism based on a regular hexahedron geometric configuration (stable state 1).

[0027] Figure 5 This is the second steady-state schematic diagram of a spatially distributed hexastable flexible mechanism based on a regular hexahedron geometric configuration (stable state 2).

[0028] Figure 6 This is the third steady-state schematic diagram of a spatially distributed hexastable flexible mechanism based on a regular hexahedron geometric configuration (stable state 3).

[0029] Figure 7 This is the fourth steady-state schematic diagram of a spatially distributed hexastable flexible mechanism based on a regular hexahedron geometric configuration (stable state 4).

[0030] Figure 8 This is the fifth steady-state schematic diagram of the spatially distributed hexastable flexible mechanism based on the regular hexahedron geometric configuration (stable state 5).

[0031] Fig. 9 This is the sixth steady-state schematic diagram of a spatially distributed hexastable flexible mechanism based on a regular hexahedron geometric configuration (stable state 6).

[0032] Fig.10 Schematic diagram of the stable-state transition path network of the spatially distributed hexastable flexible mechanism based on the regular hexahedron geometric configuration.

[0033] Fig.11 It is a structural schematic diagram of a spatially distributed octa-stable flexible mechanism based on a regular tetrahedron geometric configuration.

[0034] Fig.12 It is a schematic diagram of the stable conversion path network of a spatially distributed octastable flexible mechanism based on a regular tetrahedral geometric configuration.

[0035] Fig.13 It is a structural schematic diagram of a spatially distributed octastable flexible mechanism based on a regular octahedron geometric configuration.

[0036] Fig.14 It is a structural schematic diagram of a spatially distributed twelve-stable flexible mechanism based on the regular dodecahedron geometric configuration.

[0037] Fig.15 It is a schematic diagram of the steady-state conversion path network of a spatially distributed twelve-stable flexible mechanism based on the regular dodecahedron geometric configuration.

[0038] Fig.16 It is a structural schematic diagram of a spatially distributed twenty-stable flexible mechanism based on a regular icosahedron geometric configuration.

[0039] Fig.17 It is a schematic diagram of the steady-state conversion path network of a spatially distributed twenty-stable flexible mechanism based on the regular icosahedron geometric configuration.

[0040] Reference numerals: 1: Flexible beam; 2: Regular polyhedron outer frame before applying axial displacement preload; 3: Central body; 4. Regular polyhedron outer frame after applying axial displacement preload; 5. Axial displacement preload. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Combine the following Figure 1-Figure 17 Specific embodiments of the present invention are described.

[0043] Figure 1 is one of the structural schematic diagrams of the spatially distributed multi-stable flexible mechanism provided by the present invention, such as Figure 1 ( Figure 1 Taking a regular hexahedron as an example), the spatially distributed multi-stable flexible mechanism includes: a flexible beam group, a regular polyhedron outer frame 2 and a central body 3; wherein,

[0044] The regular polyhedron outer frame 2 is a rigid structure; The central body 3 is located at the center of the regular polyhedron outer frame 2; The flexible beam group includes a plurality of flexible beams 1; the distal end of each flexible beam 1 is respectively connected to each inner vertex of the regular polyhedron outer frame 2, and the proximal end of each flexible beam 1 is connected to the central body 3; Each stable state of the spatially distributed multi-stable flexible mechanism is a stable posture achieved after the central body 3 is twisted under the interaction of all flexible beams 1 when equal axial displacement preloads are applied to the far-center ends of each flexible beam to cause each flexible beam to buckle.

[0045] It should be noted that this embodiment takes a regular hexahedral external frame as an example to illustrate the structure and working principle of the spatially distributed multi-stable flexible mechanism. Figure 1 In the figure, the regular polyhedron frame 2 is a rigid structure with good overall rigidity, which is used to ensure the geometric configuration of the regular polyhedron frame. The regular polyhedron outer frame can be made of the same rigid material or different rigid materials, and the processing and manufacturing process is not limited. The central body 3 can be of any shape, not limited to the form of a polyhedron, on the premise that the geometric dimensions of each flexible beam are consistent, and the torsional posture in each steady state is not affected, and the central body 3 does not interfere with the flexible beam during the steady state transformation process.

[0046] The central body 3 is located at the center of the regular polyhedron outer frame 2, and the two are connected by a flexible beam group 1.

[0047] Each inner vertex of the regular polyhedron outer frame 2 is connected to the central body 3 by a flexible beam 1; that is, the total number of flexible beams 1 is equal to the total number of inner vertices of the regular polyhedron outer frame 2. The cross section of the flexible beams in the flexible beam group 1 is a centrally symmetrical figure, such as a circular cross section; the axis of the flexible beam coincides with the line connecting the inner vertex and the center point of the regular polyhedron outer frame. The flexible beam can bend under the action of external force.

[0048] The multistable characteristics of a general multistable flexible mechanism can be expressed as follows: Figure 2 The "ball on the hill" shown in the figure is used to explain this. Figure 2 In the figure, when the ball is at position A, since the gravitational potential energy in the vicinity is the same, an uncertain equilibrium position is generated, and the position where the disturbance is added is the position where the ball finally stays. When the ball is at position B, E, and H, a part of the position is applied, and the ball will swing near the position until it returns to the original position. The ball at this position is said to be in a "stable equilibrium state". When the ball is at position D and G, ideally, the ball is placed on the top of the peak and the ball can maintain balance. But in general, the ball will not be at the top of the peak. The disturbed ball will roll to the bottom of the valley and lose balance. The ball in this state is called an "unstable equilibrium state". Ideally, it will be balanced, but the balance will be destroyed by a slight disturbance. When the ball is at position C, F, and I, the ball that is not subject to external forces will move to the bottom of the valley. We call the ball at this position in an "unstable state". From this perspective, the transition process between multi-stable states is to reach another stable equilibrium point from a stable equilibrium position, and in the process, it will go through an unstable equilibrium state. For example, position B passes through position D and then reaches position E, which is a buckling process. A mechanism with more than two stable equilibrium positions is called a multistable flexible mechanism, and the total energy of the mechanism has more than two minimum points.

[0049] Notice, Figure 2 The general organizational relationship between the multi-stable states shown is linear, that is, the transitions between the stable states have a fixed order. For example, if the ball wants to reach the stable state position H from the stable state position B, it must cross or pass through the stable state position E. This feature is significantly different from the distributed organizational relationship between the multi-stable states described in this patent, that is, there are multiple paths for transitions between the stable states, and the planning and editing of the stable state transition paths between the multi-stable states can be realized.

[0050] Combine the following Figure 3 The working principle of the spatially distributed multi-stable flexible mechanism is explained. Figure 1This is the initial state of the spatial distributed multi-stable flexible mechanism before the axial displacement preload is applied. The central body remains stable in this state, and there is only one stable point. That is to say, when the axial displacement preload is not applied, the central body is connected to the outer frame through 8 flexible beams and maintains a stable state in the current posture. When the central body is held by hand and forced to change its posture, the central body is restricted by the surrounding flexible rods and will return to the stable state even if a small deflection or displacement occurs. Figure 1 The initial stable state is shown, so it can be said that there is only one stable point in the current state. Figure 3 The schematic diagram shows the process of applying axial displacement preload to the far center end of each flexible beam. If the same axial displacement preload 5 is applied to the far center end of each flexible beam 1 in the flexible beam group, the far center end of the flexible beam group changes from the original regular polyhedron geometric configuration 2 (in Figure 3 The vertices of the polyhedron (shown by double-dashed lines in Figure 3 Under the action of the axial displacement preload 5, the flexible beam 1 buckles, and under the combined action of the internal forces of the buckled flexible beam group, the center body 3 deviates Figure 1 The stable position in the stable state is stabilized again in a new stable state by rotating a certain angle around a certain coordinate axis, such as Figure 3 The final steady state (i.e. Figure 7 The centrosome twisting posture in the fourth stable state (shown in Figure 4)

[0051] It should be noted that the axis of the central body twisting and winding is the normal direction perpendicular to any face of the regular polyhedron and pointing outward, with the center of the regular polyhedron outer frame as the origin. There are as many normal lines as there are faces of the regular polyhedron outer frame, and therefore, there are as many stable states as there are states of the central body. In other words, the total number of stable states of the spatially distributed multi-stable flexible mechanism is the same as the number of faces of the regular polyhedron outer frame. Figure 3 Taking the regular hexahedron in the figure as an example, the regular hexahedron has six faces and is a strictly geometrically symmetrical structure. Therefore, the flexible mechanism can achieve six equivalent and evenly distributed stable states. The spatial postures of the central body of the flexible mechanism and the buckling flexible beam group in the above six stable states are as follows: Figure 4 (Steady state 1), Figure 5 (Steady state 2), Figure 6 (Steady state 3), Figure 7 (Steady state 4), Figure 8 (Steady state 5), Fig. 9 As shown in (Steady State 6), each steady state can be converted to another. One steady state can be converted to one of the four adjacent steady states. The six steady states are connected together through a steady state conversion path network, presenting a distributed organizational relationship. The distribution location and steady-state conversion path network in Fig.10As shown, S1, S2...S6 respectively represent the six stable states of the six-stable-state flexible mechanism.

[0052] From the energy point of view, each steady state corresponds to a potential energy minimum point of the flexible mechanism, and the transition between steady states is the transition from one potential energy minimum point to another adjacent potential energy minimum point. Fig.10 The steady-state conversion path network shown does not include the conversion path between two steady states of relative position (referring to the two relative faces in the regular polyhedron), such as from steady state 1 to steady state 4 (or steady state 2 to steady state 5, steady state 3 to steady state 6). This is because there is a maximum point with a very high potential energy value between the steady states of relative position. Through this potential energy maximum point, the stress inside the buckled flexible beam may be greater than its strength limit and cause damage; in actual operation, when the posture of the central body in the spatial angle coordinate system is close to this potential energy maximum point, it is pushed into an adjacent steady state, which does not have good practical operability. Based on the above two reasons of structural strength and actual operation, this steady-state conversion path is not adopted.

[0053] In the above embodiment, the central body is placed at the center of the outer frame of the regular polyhedron and pulled by the flexible beam group. When the flexible beam group is bent, the central body is twisted by a certain angle under the interaction of each flexible beam and reaches the next steady state from the current steady state. Since the central body is placed inside the outer frame of the regular polyhedron and the spatially distributed multi-stable flexible mechanism has a strictly symmetrical structure, the rotation of the central body around any plane normal (i.e., the direction starting from the center and perpendicular to any face of the regular polyhedron and pointing outward) is equivalent. Therefore, the stable state of the central body can be the same as the number of faces of the regular polyhedron, which can significantly increase the number of stable states of the multi-stable flexible mechanism. Since the normals of each plane point in different directions, these stable states are in the custom spatial angle coordinate system. It is spatially uniformly distributed (different from the multi-stable state of the planar state) and has a distributed organizational relationship, which improves its information expression ability and can be used as a basic logical structural unit for mechanical computing. Each steady state and steady state conversion path can be used for data storage and expression, so as to exponentially improve the information processing and computing capabilities of mechanical computing.

[0054] In addition, the space-distributed multi-stable flexible mechanism can also be used for cryptographic compilation; based on the rich and diverse torsional postures of its central body, the space-distributed multi-stable flexible mechanism can also be used as a space pointing mechanism for space exploration.

[0055] In one embodiment, the above-mentioned flexible beam has a circular cross-section and is isotropic in all bending directions; the geometric parameters of each flexible beam in the above-mentioned flexible beam group are the same; the geometric parameters include the diameter of the circular cross-section of the flexible beam, the length of the flexible beam, and the magnitude of the axial displacement preload applied at the far end of the flexible beam.

[0056] Among them, isotropy refers to the property that the physical, chemical and other properties of an object will not change due to different directions, that is, the performance values ​​of an object measured in different directions are exactly the same, also known as homogeneity.

[0057] Generally, the cross section of the flexible beam is circular to ensure that the flexible beam is isotropic in each bending direction. In addition, in order to ensure the strict symmetry of the entire spatially distributed multi-stable flexible mechanism, it is also necessary to ensure that the geometric parameters of each flexible beam in the flexible beam group are the same, wherein the geometric parameters include the diameter of the cross section of the flexible beam, the length of the flexible beam, and the magnitude of the axial displacement preload applied to the far center end of the flexible beam.

[0058] The above embodiment ensures the strict symmetry of the spatially distributed multi-stable flexible mechanism by setting the material properties and physical properties of each flexible beam to be the same, ensures that the central body can achieve an equivalent steady state when twisted along different coordinate axes (except for different spatial distribution and spatial direction), and ensures the presentation of spatially distributed multi-stable state.

[0059] In one embodiment, in the above-mentioned spatially distributed multi-stable flexible mechanism, the torsion direction of the central body 3 during torsion is the positive direction of the normal around a face of the regular polyhedron outer frame 2; wherein the positive direction of the normal is a direction perpendicular to the face and pointing outward with the center as the origin; and the torsion angle of the central body 3 is positively correlated with the magnitude of the axial displacement preload 5 applied to the flexible beam 1.

[0060] Specifically, at the far center end of the flexible beam group, equidistant axial displacement preloads are simultaneously applied to cause the flexible beam group to buckle. Under the interaction of the internal forces of the flexible beam group, the center body immediately deviates from the initial position to a torsion angle of The posture is stabilized to a new steady state again, and the twisting direction is the positive direction of the normal line around one face of the regular polyhedron. The size of is positively correlated with the size of the axial displacement preload 5 applied to the flexible beam 1.

[0061] The above embodiment applies equidistant axial displacement preloads to cause the flexible beam group to buckle, so that the central body twists under the buckling action of all the flexible beams to achieve a steady state, providing a simple method for constructing a multi-stable state.

[0062] In one embodiment, the stable states of the spatially distributed multi-stable flexible mechanism correspond one-to-one to the faces of the regular polyhedron outer frame; the central body can transform from the current stable state to the stable state corresponding to any adjacent face of the current corresponding face.

[0063] Specifically, since the torsion direction of the central body can be along the normal of any face, the final steady state reached is also different in spatial distribution. Therefore, it can be considered that the steady state of the above-mentioned spatially distributed multi-stable flexible mechanism is one-to-one corresponding to the face of the regular polyhedron outer frame; the central body can transform from the current steady state to the steady state corresponding to any adjacent face of the current corresponding face.

[0064] The above embodiment, by making a one-to-one correspondence between each stable state and each surface, is conducive to defining the steady-state conversion path of the central body and providing a physical basis for data storage and expression.

[0065] In one embodiment, the regular polyhedral outer frame is any one of a regular tetrahedral outer frame, a regular hexahedral outer frame, a regular octahedral outer frame, a regular dodecahedral outer frame and a regular icosahedral outer frame.

[0066] Among them, the spatially distributed multistable flexible mechanism using the outer frame of a regular hexahedron can realize a distributed six-stable state, the spatially distributed multistable flexible mechanism using the outer frame of a regular octahedron can realize a distributed eight-stable state, the spatially distributed multistable flexible mechanism using the outer frame of a regular dodecahedron can realize a distributed twelve-stable state, and the spatially distributed multistable flexible mechanism using the outer frame of a regular icosahedron can realize a distributed twenty-stable state; the spatially distributed multistable flexible mechanism using the outer frame of a regular tetrahedron is a special case, and each of its faces corresponds to two stable states rotating clockwise and counterclockwise around the normal of the face respectively. The spatially distributed multistable flexible mechanism using the outer frame of a regular tetrahedron can realize a total of distributed eight-stable states.

[0067] Specifically, according to the knowledge of geometry, there are only five regular polyhedrons, namely, the regular tetrahedron, the regular hexahedron, the regular octahedron, the regular dodecahedron and the regular icosahedron. Based on these five regular polyhedron geometric configurations, according to the aforementioned structural scheme, in addition to the six-stable flexible mechanism corresponding to the regular hexahedron already introduced, an eight-stable flexible mechanism, a twelve-stable flexible mechanism and a twenty-stable flexible mechanism can also be constructed in turn.

[0068] Optionally, when the regular polyhedron outer frame is the regular tetrahedron outer frame and one of the flexible beam groups is in a fixed support form, the spatially distributed multi-stable flexible mechanism has 8 stable states.

[0069] Fig.11The figure shows the schematic diagram of the structure of the spatially distributed eight-stable-state flexible mechanism based on the geometric configuration of a regular tetrahedron before the displacement preload is applied to the flexible beam group of the present invention. It should be noted that after the displacement preload is applied to the flexible beam group to cause it to buckle, the central body has two stable states of clockwise / counterclockwise twisting around the normal of each face of the regular tetrahedron. Therefore, there are a total of eight stable states; in each stable state, the flexible beam coaxial with the rotation axis of the central body needs to be clamped and fixed with an additional device. The corresponding spatial eight stable states in a distributed organizational relationship and their stable state conversion path network are shown as follows: Fig.12 shown.

[0070] Fig.13 The figure shows the structure of the spatially distributed eight-stable flexible mechanism based on the regular octahedron geometric configuration before the displacement preload is applied to the flexible beam group. In each stable state, the central body is twisted at a certain angle around the positive direction of the normal line of one face of the octahedron. The corresponding spatial eight stable states and their stable state conversion path network in a distributed organizational relationship are shown in FIG. Fig.12 shown.

[0071] Fig.14 The figure shows the structure of the spatial distributed twelve-stable flexible mechanism based on the geometric configuration of the regular dodecahedron before the displacement preload is applied to the flexible beam group. In each stable state, the central body is twisted at a certain angle around the positive direction of the normal line of one face of the dodecahedron. The corresponding spatial 12 stable states and their stable state conversion path network in a distributed organizational relationship are shown in FIG. Fig.15 shown.

[0072] Fig.16 The figure shows the structure of the spatial distributed 20-stable-state flexible mechanism based on the regular icosahedron geometric configuration before the displacement preload is applied to the flexible beam group. In each stable state, the central body is twisted at a certain angle around the positive direction of the normal line of one face of the icosahedron. The corresponding spatial 20-stable state and its stable state conversion path network in a distributed organizational relationship are shown in FIG. Fig.17 shown.

[0073] The above embodiments, by demonstrating flexible mechanisms based on the geometric configurations of a regular tetrahedron, a regular hexahedron, a regular octahedron, a regular dodecahedron and a regular icosahedron, provide more possibilities for the application expansion of flexible mechanisms and provide more directions for the research of flexible mechanisms.

[0074] In one embodiment, when the regular polyhedron outer frame is the regular tetrahedron outer frame and one of the flexible beam groups is in a fixed support form, the spatially distributed multi-stable flexible mechanism has eight stable states.

[0075] The steady-state construction method provided by the present invention is described below. The steady-state construction method described below is applied to the spatially distributed multi-stable flexible mechanism in the above embodiment.

[0076] In one embodiment, the present application also provides a steady-state construction method, comprising: applying an equidistant axial displacement preload to the far center end of the flexible beam group, so that when the flexible beam group is bent, the center body is stabilized in a new steady state in a posture after being twisted by a certain angle under the interaction of all the flexible beams.

[0077] Specifically, Figure 3 The process of applying axial displacement preload is shown. If the same axial displacement preload is applied to the far center end of each flexible beam in the flexible beam group, the far center end of the flexible beam group moves from the vertex of the original regular polyhedron geometric configuration 2 to the vertex of the new regular polyhedron geometric configuration 4. Under the action of the axial displacement preload, the flexible beam 1 buckles. Under the combined action of the internal forces of the buckled flexible beam group, the center body 3 deviates from Figure 1 The stable position in the stable state is stabilized again in a new stable state by rotating a certain angle around a certain coordinate axis, such as Figure 3 Shown is the twisted posture of the centrosome in steady state 4.

[0078] In the above embodiment, by applying an axial displacement preload to the flexible beam, the central body can be controlled to complete the torsion under the interaction of each flexible beam, thereby realizing the conversion of the spatial steady state, thereby realizing a spatially distributed multi-stable flexible mechanism.

[0079] In one embodiment, the above-mentioned method of applying an equidistant axial displacement preload to the distal end of the flexible beam group includes: (1) applying an equidistant axial displacement preload to the distal end of the flexible beam group along the axial direction using a linear displacement motor; or,

[0080] (2) shortening all sides of the regular polyhedron outer frame at equal distances to achieve applying an axial displacement preload of equal distances to the far center end of the flexible beam group; or,

[0081] (3) Increasing the actual length of the flexible beam so that the actual length of the flexible beam is greater than the distance between the central body and the inner vertex of the regular polyhedron outer frame.

[0082] Specifically, the method of applying axial displacement preload includes: 1) using a linear displacement motor to apply equidistant axial displacement preload to the flexible beam group along the axial direction through motor control; 2) shortening all sides of the regular polyhedron outer frame at equal distances; 3) using a flexible beam group whose actual length is greater than the distance between the central body and the inner vertex of the regular polyhedron outer frame.

[0083] The above three methods can realize the application of equidistant axial displacement preload to the flexible beam group, providing conditions for steady-state conversion.

[0084] In one embodiment, a steady-state construction method is also provided, including: applying a force to the central body so that the central body is stabilized in another steady state in the distributed multi-stable state in a posture after being twisted by a certain angle, thereby completing the steady-state conversion; or, changing the bending direction of any flexible beam in the flexible beam group so that the central body 3 is stabilized in another steady state in the distributed multi-stable state in a posture after being twisted by a certain angle under the interaction of the multiple flexible beams 1, thereby completing the steady-state conversion.

[0085] Specifically, the steady-state transformation can be achieved by manually twisting the central body, or the transformation between the above-mentioned steady states can be achieved by manually changing the buckling direction of any buckled flexible beam in the flexible beam group.

[0086] The above steady-state construction method, by providing a variety of ways to convert steady states, enables the spatially distributed multi-stable flexible mechanism to flexibly change steady states according to actual conditions, and can plan, design and edit steady-state conversion paths according to needs, thereby completing the construction of a steady-state conversion path network. At the same time, it also provides new inspiration and ideas for the innovative design of multi-stable flexible mechanisms.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A spatially distributed multi-stable flexible mechanism, characterized in that: include: A flexible beam group, a regular polyhedron outer frame (2) and a central body (3); wherein, The regular polyhedron outer frame (2) is a rigid structure; The central body (3) is located at the center of the regular polyhedron outer frame (2); The flexible beam group comprises a plurality of flexible beams (1); the distal end of each flexible beam (1) is respectively connected to each inner vertex of the regular polyhedron outer frame (2), and the proximal end of each flexible beam (1) is connected to the central body (3); Each stable state of the spatially distributed multi-stable flexible mechanism is a stable posture achieved after the central body (3) is twisted under the interaction of all the flexible beams (1) when equal axial displacement preloads are applied to the far-center ends of the flexible beams to cause the flexible beams to buckle.

2. The spatially distributed multi-stable flexible mechanism according to claim 1, characterized in that: The flexible beam (1) has a circular cross-section and is isotropic in each bending direction; the geometric parameters of each flexible beam (1) in the flexible beam group are the same; the geometric parameters include the diameter of the cross-section of the flexible beam, the length of the flexible beam, and the size of the axial displacement preload (5) applied to the far center end of the flexible beam.

3. The spatially distributed multi-stable flexible mechanism according to claim 1, characterized in that: The twisting direction of the central body (3) during twisting is the positive direction of the normal line around a face of the regular polyhedral outer frame (2); wherein the positive direction of the normal line is a direction perpendicular to the face and pointing outwards with the center as the origin; and the twisting angle of the central body (3) is positively correlated with the magnitude of the axial displacement preload (5) applied to the flexible beam (1).

4. The spatially distributed multi-stable flexible mechanism according to claim 1, characterized in that: The stable states of the spatially distributed multi-stable flexible mechanism correspond one-to-one to the faces of the regular polyhedral outer frame (2); the central body (3) can transform from a current stable state to a stable state corresponding to any adjacent face of the current corresponding face.

5. The spatially distributed multi-stable flexible mechanism according to claim 1, characterized in that: The regular polyhedral outer frame (3) is any one of a regular tetrahedral outer frame, a regular hexahedral outer frame, a regular octahedral outer frame, a regular dodecahedral outer frame and a regular icosahedral outer frame.

6. The spatially distributed multi-stable flexible mechanism according to claim 5, characterized in that: The spatially distributed multi-stable flexible mechanism using the outer frame of a regular hexahedron can realize a distributed six-stable state, the spatially distributed multi-stable flexible mechanism using the outer frame of a regular octahedron can realize a distributed eight-stable state, the spatially distributed multi-stable flexible mechanism using the outer frame of a regular dodecahedron can realize a distributed twelve-stable state, and the spatially distributed multi-stable flexible mechanism using the outer frame of a regular icosahedron can realize a distributed twenty-stable state; each face of the spatially distributed multi-stable flexible mechanism using the outer frame of a regular tetrahedron corresponds to two stable states rotating clockwise and counterclockwise around the normal of the face respectively, and the spatially distributed multi-stable flexible mechanism using the outer frame of a regular tetrahedron can realize a total of distributed eight-stable states.

7. The spatially distributed multi-stable flexible mechanism according to claims 1 to 6, characterized in that: The multiple stable states of the spatially distributed multi-stable flexible mechanism are spatially uniformly distributed, and there is a distributed organizational relationship between the stable states.

8. A stable construction method, applied to the spatially distributed multi-stable flexible mechanism according to any one of claims 1 to 7, characterized in that: The method comprises: An equidistant axial displacement preload is applied to the far center end of the flexible beam group, so that when the flexible beam group buckles, the central body (3) is stabilized in a new steady state in a posture twisted by a certain angle under the interaction of all the flexible beams (1).

9. The method for building a steady state according to claim 8, characterized in that: Applying an equidistant axial displacement preload to the far center end of the flexible beam group includes: Using a linear displacement motor to apply an equidistant displacement preload along the axis direction to the far center end of the flexible beam group; or, All sides of the regular polyhedron outer frame (2) are shortened at equal distances, so as to achieve the application of an axial displacement preload at equal distances to the far center end of the flexible beam group; or, The actual length of the flexible beam is increased so that the actual length of the flexible beam (1) is greater than the distance between the central body (3) and the inner vertex of the regular polyhedron outer frame (2).

10. A stable construction method, applied to the spatially distributed multi-stable flexible mechanism according to any one of claims 1 to 7, characterized in that: The method comprises: applying a force to the central body (3) so that the central body (3) is stabilized in a new steady state in a posture after being twisted by a certain angle, thereby realizing steady state conversion between multiple stable states with distributed organizational relationships; or, The bending direction of any one of the flexible beams (1) in the flexible beam group is changed so that the central body (3) is stabilized in a new steady state in a posture twisted by a certain angle under the interaction of the multiple flexible beams (1), thereby realizing steady state conversion between multiple stable states with distributed organizational relationships.

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