Variable Stiffness Flexible Manipulator

Abstract

The present invention relates to a variable stiffness flexible manipulator, which includes a heat insulation sleeve, a low melting point alloy layer and an elastic skeleton; wherein: sealing end plugs are respectively arranged at two end parts of the heat insulation sleeve; the low melting point alloy layer is filled in the heat insulation sleeve, the elastic skeleton is arranged in the low melting point alloy layer, the elastic skeleton is provided with a fluid circulation channel by itself, and the fluid circulation channel is communicated with an external pipeline through the sealing end plugs arranged at one side end or both ends of the heat insulation sleeve to realize fluid circulation. The present invention combines the elastic skeleton with the energy exchange layer, realizes the integrated design of the structure and dual functions, not only reduces the overall radial size of the manipulator, but also improves the bending curvature characteristics of the manipulator, has stronger environmental adaptability and application range, and can especially meet the requirements of operating the manipulator in a narrow space.

Description

Technical Field

[0001] The present invention relates to a flexible manipulator, and more particularly to a flexible manipulator with a small radial dimension and good bending curvature characteristics that realizes variable stiffness based on a low melting point alloy. Background Art

[0002] With the continuous development of robot technology, rigid robot technology with a rigid structure as the main body has become increasingly mature and has been widely used in industrial production, food processing, medical and health care and other scenarios. However, the characteristics of the rigid structure determine that it has problems such as complex structure, limited flexibility, poor safety and adaptability; for example, in some unstructured application scenarios, such as grasping complex and fragile objects, human-robot interaction and operation in narrow spaces, there are still great deficiencies.

[0003] Therefore, the development of flexible robot technology has become an effective way to solve the above problems. Soft robots developed by using fluids, gels, shape memory polymers and other materials by taking biological organisms in nature as bionic objects achieve flexible adjustment. Therefore, soft robots have elastic and deformable properties and have the ability to withstand large deformations. In this case, the morphological structure and dimensional parameters can be adjusted according to the characteristics of the environment or the interaction object to complete the target task. However, since such flexible robots lack a rigid structure as a support, they generally have deficiencies such as low precision, poor repeatability, small load capacity, and low stiffness, which in turn limits their practical application value. Therefore, in this situation, it is particularly important to develop variable stiffness technology for flexible robots. At present, flexible robot variable stiffness technology can be divided into two categories from the implementation principle:

[0004] Variable stiffness technology based on structure and variable stiffness technology based on material:

[0005] (1) Variable stiffness technology based on structure: mainly realizes the rigid-flexible conversion by changing the cooperation relationship between structural components, including through the meshing, antagonistic arrangement and blocking principle between structures, etc.; the flexible robot manipulator with such a structure still has deficiencies such as limited flexibility and poor adaptability;

[0006] (2) Ways to achieve variable stiffness using materials: Specific materials are mainly used (such as phase change materials: (low melting point alloys, thermoplastic polymers, etc.), rheological fluids (electrorheological and magnetorheological fluids), shape memory materials, etc.) that can adjust their stiffness according to external stimuli. Among them: The variable stiffness flexible robot manipulator designed based on low melting point alloy materials often adopts a concentric tube layout with functional layers stacked, mainly including a heat insulation layer, an energy exchange layer, a low melting point alloy filling layer, and in some cases, a driving layer for motion control and an elastic skeleton added to improve the bending curvature. Each functional layer is separated by a silicone layer. This setting method results in the currently emerging soft robot manipulators designed based on low melting point alloy materials generally having a large radial diameter, structural redundancy, and difficulty in meeting the requirements of operating in narrow spaces. For example: Specific operations such as pipeline maintenance or exploration in natural human body cavities cannot be implemented. Therefore, usually, in order to reduce the radial size, generally in the design, an elastic skeleton is not introduced into the manipulator; however, the manipulator without an elastic skeleton has poor curvature characteristics and great difficulty in precise motion control, which further restricts the use scenarios of such manipulators. Summary of the Invention

[0007] To solve the above problems, the present invention provides a variable stiffness flexible manipulator designed based on phase change materials. By setting an elastic skeleton with a self - contained fluid circulation channel in the low melting point alloy layer, the elastic skeleton and the energy exchange layer are combined into one, which not only effectively reduces the overall radial size of the manipulator; at the same time, the retention of the elastic skeleton effectively improves the bending curvature characteristics of the manipulator and creates a prerequisite for the high - precision motion control of the manipulator.

[0008] The technical solution adopted by the present invention to solve the above technical problems is: A variable stiffness flexible manipulator, characterized in that it includes:

[0009] A heat insulation sleeve, with sealing end plugs respectively arranged at both ends;

[0010] A low melting point alloy layer, filled and arranged inside the heat insulation sleeve;

[0011] An elastic skeleton, arranged in the low melting point alloy layer, the elastic skeleton has a self - contained fluid circulation channel, and the fluid circulation channel is connected to an external pipeline through the sealing end plugs arranged at one or both ends of the heat insulation sleeve to realize fluid circulation.

[0012] Preferably, the sealing end plugs arranged at both ends of the heat insulation sleeve are respectively a proximal end plug and a distal end plug; one end of the elastic skeleton is fixed on the proximal end plug, and the other end is movably embedded on the distal end plug.

[0013] Preferably, the elastic framework is a double - helix elbow with a fluid circulation channel. One end of the double - helix elbow is closed and movably embedded in the distal end plug, and the other end is connected to an external pipeline through the proximal end plug to realize fluid circulation. The heat - insulating sleeve is cylindrical, and an instrument through - tube is coaxially arranged inside the cylindrical heat - insulating sleeve. The double - helix elbow is arranged around the instrument through - tube.

[0014] Preferably, the elastic framework includes a plurality of elastic straight pipes with fluid circulation channels. A liquid chamber communicating with the plurality of elastic straight pipes is provided on the distal end plug. The plurality of elastic straight pipes are respectively connected to an external pipeline through the proximal end plug to realize fluid circulation. The heat - insulating sleeve is cylindrical, and the plurality of elastic straight pipes are uniformly arranged along the circumferential direction, and the central axis of the cylindrical structure formed by enclosing the plurality of elastic straight pipes coincides with the central axis of the heat - insulating sleeve.

[0015] As a further preference, a number of elastic joint discs are connected to the plurality of elastic straight pipes uniformly arranged along the circumferential direction, and the outer peripheral walls of the respective elastic joint discs are in contact with the inner wall of the heat - insulating sleeve.

[0016] As a further preference, a number of liquid metal flow grooves are respectively provided on the respective elastic joint discs.

[0017] Preferably, the elastic framework includes at least one elastic straight pipe with a fluid circulation channel. One end of the elastic straight pipe is connected to an external pipeline through the proximal end plug, and the other end is connected to an external pipeline through the distal end plug to realize fluid circulation.

[0018] Preferably, the number of the elastic straight pipes is multiple, and the multiple elastic straight pipes are uniformly arranged along the circumferential direction. The heat - insulating sleeve is cylindrical, and the central axis of the cylindrical structure formed by enclosing the multiple elastic straight pipes uniformly arranged along the circumferential direction coincides with the central axis of the heat - insulating sleeve. A number of elastic joint discs are connected to the multiple elastic straight pipes.

[0019] Preferably, the elastic framework is a single - helix elbow with a fluid circulation channel. One end of the single - helix elbow is connected to an external pipeline through the proximal end plug, and the other end is connected to an external pipeline through the distal end plug to realize fluid circulation.

[0020] As a further preference, the heat - insulating sleeve is cylindrical, and an instrument through - tube is coaxially arranged inside the cylindrical heat - insulating sleeve. The single - helix elbow is arranged around the instrument through - tube.

[0021] The present invention has the following advantages and effects compared with the prior art:

[0022] 1. In the variable-stiffness flexible manipulator of the present invention, by integrally providing a fluid circulation channel on the elastic framework, the separate setting of the energy conversion channel for realizing the variable-stiffness adjustment of the low-melting-point alloy layer is avoided, making the overall radial dimension of the manipulator smaller and having a wider application range. It can be applied to pipeline maintenance and also perform surgical operations in narrow human body cavities. Secondly, in the manipulator of the present invention, the elastic framework that also serves as an energy conversion channel is provided, making the stress distribution in the axial direction of the flexible joint more uniform. The deformation of the overall joint can smoothly yield to the externally applied load, and effectively avoid the stress concentration phenomenon that occurs when the flexible joint is stressed. Subsequently, the overall manipulator has good bending flexibility and high curvature characteristics.

[0023] 2. In the variable-stiffness flexible manipulator of the present invention, the elastic framework provided with a fluid circulation channel is placed inside the low-melting-point alloy layer, realizing the transfer of the energy of the fluid medium introduced into the circulation channel of the elastic framework from the inner center to the outside of the low-melting-point alloy layer. Compared with the traditional transfer method of covering the energy exchange layer outside the low-melting-point alloy layer, the energy transfer is more uniform and the conduction efficiency is higher. It can effectively shorten the time of rigid-flexible conversion, improve the efficiency of rigid-flexible conversion, and then ensure the effect of rigid-flexible conversion.

[0024] 3. In the variable-stiffness flexible manipulator of the present invention, the elastic framework is a double-helix bent pipe, the heat insulation sleeve is cylindrical, and an instrument through pipe is coaxially arranged inside the cylindrical heat insulation sleeve. The double-helix bent pipe is wound around the instrument through pipe; this structural setting makes the energy exchange channel located at the central position of the low-melting-point alloy layer; when energy exchange fluid is input into the fluid circulation channel, the energy diffuses and transfers from the inner center of the low-melting-point alloy layer to the four peripheries, thereby achieving a more uniform heat conduction effect and a higher heat conduction efficiency, and further shortening the time of rigid-flexible conversion and improving the efficiency of rigid-flexible conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is a schematic three-dimensional structure diagram of the variable-stiffness flexible manipulator of the present invention.

[0027] Figure 2 It is a schematic split structure diagram of the variable-stiffness flexible manipulator according to Embodiment 2 of the present invention.

[0028] Figure 3Schematic cross-sectional structure diagram of the variable stiffness flexible manipulator described in Embodiment 2 of the present invention.

[0029] Figure 4 Schematic diagram of the equidistant and equal-diameter double-helix bent pipe structure (Figure a) and the non-equidistant and non-equal-diameter double-helix bent pipe structure (Figure b) in the variable stiffness flexible manipulator described in Embodiment 2 of the present invention.

[0030] Figure 5 Schematic three-dimensional structure diagram of the proximal end plug (Figure a) and the distal end plug (Figure b) in the variable stiffness flexible manipulator described in Embodiment 2 of the present invention.

[0031] Figure 6 、 Figure 7 Schematic split structure diagram of the variable stiffness flexible manipulator described in Embodiment 3 of the present invention.

[0032] Figure 8 Schematic cross-sectional structure diagram of the variable stiffness flexible manipulator described in Embodiment 3 of the present invention.

[0033] Figure 9 Schematic split structure diagram of the variable stiffness flexible manipulator described in Embodiment 4 of the present invention.

[0034] Figure 10 Schematic cross-sectional structure diagram of the variable stiffness flexible manipulator described in Embodiment 4 of the present invention.

[0035] Figure 11 Schematic three-dimensional structure diagram of the elastic joint disc in Embodiment 4 of the present invention.

[0036] Figure 12 Schematic three-dimensional structure diagram of the variable stiffness flexible manipulator described in Embodiment 5 of the present invention.

[0037] Figure 13 Schematic internal structure diagram of one structural form of the variable stiffness flexible manipulator described in Embodiment 5 of the present invention.

[0038] Figure 14 Schematic internal structure diagram of one structural form of the variable stiffness flexible manipulator described in Embodiment 5 of the present invention.

[0039] Figure 15 Schematic split structure diagram of one structural form of the variable stiffness flexible manipulator described in Embodiment 5 of the present invention.

[0040] Figure 16 Schematic diagram of the single-helix bent pipe in the variable stiffness flexible manipulator described in Embodiment 5 of the present invention.

[0041] Label description: 1. Heat insulation sleeve; 11. Proximal end plug; 111. Installation pipe hole; 112. Installation interface; 12. Distal end plug; 121. Distal interface; 2. Elastic skeleton; 21. Fluid circulation channel; 22. Fluid input conduit; 23. Fluid output conduit; 3. Low melting point alloy layer; 4. Instrument through pipe; 5. External pipeline; 6. Elastic joint disc; 61. Straight pipe installation hole; 62. Liquid metal flow groove. Specific implementation mode

[0042] The following further elaborates on the present invention in conjunction with embodiments. The following embodiments are explanations of the present invention, and the present invention is not limited to the following embodiments.

[0043] Embodiment 1: As Figures 1 to 15 shown, a variable stiffness flexible manipulator arm includes a heat insulation sleeve 1, a low melting point alloy layer 3, and an elastic skeleton 2; wherein:

[0044] Sealing end plugs are respectively arranged at both ends of the heat insulation sleeve 1;

[0045] The low melting point alloy layer 3 is filled and arranged inside the heat insulation sleeve 1, and the elastic skeleton 2 is arranged in the low melting point alloy layer 3;

[0046] The elastic skeleton 2 is provided with a fluid circulation channel 21 by itself. The fluid circulation channel 21 is communicated with an external pipeline 5 through the sealing end plugs arranged at one side end or both ends of the heat insulation sleeve 1 to realize fluid circulation.

[0047] Among them: In the variable stiffness flexible manipulator arm of the present invention:

[0048] The heat insulation sleeve 1 is a sleeve made of silica gel material. The shape of the sleeve is preferably but not limited to a cylindrical shape. Among them: The cylindrical heat insulation sleeve can uniformly realize the omnidirectional bending of the manipulator arm; the low melting point alloy layer 3 is very sensitive to temperature changes. When the temperature is higher than its melting point, it is in a liquid state, and when it is lower than its melting point, it is in a solid state. Under the action of a heat / cold cycle medium, the phase change characteristics of the low melting point alloy can be used to achieve the effect of rigid-flexible transformation.

[0049] The elastic skeleton 2 is provided with a fluid circulation channel by itself. Its interior should be set to be hollow and is made of a material with good elasticity and high thermal conductivity. In the prior art, such materials are relatively common and are not listed in this application;

[0050] Furthermore, in this embodiment, the fluid refers to an energy exchange medium used to realize the phase change of the low melting point alloy layer 3.

[0051] Specifically, the variable stiffness flexible manipulator arm in this embodiment realizes variable stiffness adjustment through the following method:

[0052] As Figure 1As shown, the sealing end plugs arranged at both ends of the heat insulating sleeve 1 are respectively defined as a proximal end plug 11 and a distal end plug 12;

[0053] like Figure 3 , Figure 12 As shown, the external pipeline 5 for fluid input and output is arranged on the proximal end plug 11, or the external pipeline 5 for fluid input and output is arranged on the proximal end plug 11 and the distal end plug 12 respectively;

[0054] Circulating hot / cold fluid is introduced into the fluid circulation channel 21 on the elastic skeleton connected thereto through the external pipeline 5, so that the low melting point alloy layer 3 undergoes a phase change, thereby achieving the effect of rigid-flexible transformation of the operating arm.

[0055] Compared with the flexible robot manipulator designed based on low melting point alloy (LMPA) in the prior art, the variable stiffness flexible manipulator described in this embodiment is only composed of a heat insulation sleeve 1, a low melting point alloy layer 3 and an elastic skeleton 2, wherein: the elastic skeleton 2 has a fluid circulation channel and is arranged inside the low melting point alloy layer 3; this arrangement has the following two main characteristics:

[0056] (1) The setting of the elastic skeleton 2 can effectively improve the curvature characteristics of the operating arm on the one hand; on the other hand, the fluid circulation channel 21 is set in the elastic skeleton, so that the fluid circulation channel is located inside the low-melting-point alloy layer 3. This conduction method from inside to outside can effectively improve the energy conduction efficiency and reduce the rigid-flexible conversion time;

[0057] (2) The elastic skeleton 2 is also used as an energy conversion channel, so that the number of functional layers of the operating arm is reduced (including only a variable stiffness layer + an energy exchange layer); at the same time, the energy exchange layer also has the function of an elastic skeleton, so that the operating arm not only has the advantages of a simple structure and a small overall radial size, but also has good bending flexibility.

[0058] In summary, this embodiment cleverly combines the elastic skeleton with the energy exchange layer to achieve an integrated design of structure and dual functions (elastic skeleton + energy conversion), which not only reduces the overall radial size of the manipulator arm, but also improves the bending curvature characteristics of the manipulator arm. It has stronger environmental adaptability and application range, and can especially meet the needs of implementing manipulation in narrow spaces, thereby effectively overcoming the problem of limited application of variable stiffness manipulators for existing flexible robots due to complex functional layer settings, large radial dimensions, and difficult motion control.

[0059] When the operating arm described in Example 1 of the present invention is used in a specific application, a corresponding driving mode can be selected according to needs. Currently, the conventional driving modes in flexible robot manipulators mainly include: wire driving, pneumatic driving, electroactive polymer driving and shape memory alloy driving.

[0060] Example 2: As Figures 1 to 5 shown, based on the variable stiffness flexible manipulator described in Example 1, the structural settings of the elastic skeleton 2, the proximal end plug 11, and the distal end plug 12 and the connection relationships between them are defined as follows:

[0061] As Figure 4 shown, the elastic skeleton 2 is set as a double - helix elbow with a self - contained fluid circulation channel 21. The double - helix elbow can be formed by winding an internally hollow elastic heat - exchange tube. One end of the whole elbow is in a closed state (here, "closed" means there is no opening), and the other end is respectively provided with a fluid inlet tube 22 and a fluid outlet tube 23 connected to the fluid circulation channel 21. Among them: The double - helix elbow includes the following two structural forms: (1) The double - helix elbow is an equidistant double - helix elbow, and the equidistant spiral elbow includes two cases of equal - diameter and unequal - diameter. In this embodiment, in order to ensure the uniformity of the overall stress distribution of the manipulator, the case of equidistant and equal - diameter is preferably selected, as Figure 4 (a) shown; (2) The double - helix elbow is a non - equidistant double - helix elbow, and the non - equidistant double - helix elbow also includes two cases of equal - diameter and unequal - diameter, Figure 4 (b) shows the case of non - equidistant and unequal - diameter. (Here, "equal - diameter" means that the middle diameters of the double - helix elbows are all equal) As Figure 5 (a) shown, the proximal end plug 11 is respectively provided with mounting tube holes 111 matching the fluid inlet tube 22 and the fluid outlet tube 23; A liquid chamber for connecting the fluid inlet tube 22 and the fluid outlet tube 23 to the external pipeline 5 is arranged on the proximal end plug 11, and two mounting interfaces 112 for connecting to the external pipeline 5 are arranged on the liquid chamber;

[0062] As Figure 5 (b) shown, the distal end plug 12 is provided with a distal interface 121 matching the other end of the double - helix elbow;

[0063] As Figure 3 shown, one end of the double - helix elbow is bonded to the mounting tube hole 111 on the proximal end plug 11 through the fluid inlet tube 22 and the fluid outlet tube 23, and the other end is movably embedded in the distal interface 121; Among them: Movably embedding means that one end of the double - helix elbow is a free end, embedded in the distal end plug, and can slide without detaching from the distal end plug 12; This setting method can not only ensure better bending deformation of the elastic skeleton, but also enable the deformation of the overall joint of the manipulator to smoothly yield to the externally applied load, thereby further improving the bending curvature characteristics of the manipulator.

[0064] In the variable stiffness flexible manipulator described in this embodiment, as a preferred implementation method:

[0065] As shown Figure 3 in the figure, the heat insulation sleeve 1 is defined as a cylinder, and an instrument through tube 4 is coaxially arranged inside the cylindrical heat insulation sleeve 1. The double spiral bent tube is arranged around the instrument through tube 4, so that the double spiral bent tube is located at the central position of the low melting point alloy layer 3. When an energy exchange fluid is input into the fluid circulation channel of the double spiral bent tube, energy diffuses and transfers from the inner center of the low melting point alloy layer 3 to the four surrounding edges, so as to achieve a more uniform heat conduction effect and a higher heat conduction efficiency, and further shorten the time of rigid-flexible transformation and improve the efficiency of rigid-flexible transformation.

[0066] Embodiment 3: As Figures 6 to 8 shown in the figure, on the basis of Embodiment 1, this embodiment provides another variable stiffness flexible operating arm, and the difference from Embodiment 2 is that:

[0067] The structural settings and the connection relationships among the elastic framework 2, the proximal end plug 11, and the distal end plug 12 are defined as follows:

[0068] As Figure 6 、 Figure 7 shown in the figure, the elastic framework 2 includes a plurality of elastic straight tubes with self-contained fluid circulation channels. A liquid chamber communicating with the plurality of elastic straight tubes is provided on the distal end plug 12. The plurality of elastic straight tubes are respectively communicated with an external pipeline 5 through the proximal end plug to realize fluid circulation.

[0069] Specifically, in the variable stiffness flexible operating arm of this embodiment:

[0070] The elastic straight tube with a self-contained fluid circulation channel is interpreted as: a tubular structure with openings at both ends and a hollow interior. Preferably, the number of the elastic straight tubes is limited to an even number; among them: 1 / 2 of the number of elastic straight tubes are used to input the energy exchange fluid, and 1 / 2 of the number of elastic straight tubes are used to output the energy exchange fluid;

[0071] Installation pipe holes with the same number, cross-sectional shape, and hole diameter as the elastic straight tubes are respectively arranged on the proximal end plug 11 and the distal end plug 12; one ends of the plurality of elastic straight tubes are fixed in the installation pipe holes of the proximal end plug 11 by bonding, and the other ends are embedded in the installation pipe holes of the distal end plug 12 and can slide in the installation pipe holes without falling out during sliding;

[0072] As one of the setting methods, as Figure 5 (a) shown, a liquid chamber for communicating the plurality of elastic straight tubes with the external pipeline 5 is arranged on the proximal end plug 11, and two installation interfaces for connecting with the external pipeline 5 are arranged on the liquid chamber.

[0073] As Figure 8As shown, in the variable stiffness flexible operating arm described in this embodiment 3, the circulation mode of the energy exchange fluid is:

[0074] The energy fluid is input into 1 / 2 of the elastic straight tubes through the external pipeline 5 arranged on the proximal end plug 11, and flows into the liquid chamber on the distal end plug 12, and then flows into another 1 / 2 of the elastic straight tubes through the liquid chamber, and flows out through the external pipeline arranged on the proximal end plug 11.

[0075] It should be noted that the assembly gap between the mounting tube hole on the distal end plug 12 and the free end of the elastic straight tube should ensure that the elastic straight tube can slide while avoiding the outflow of liquid metal or the inflow of circulating medium into the low-melting-point alloy layer as much as possible.

[0076] Furthermore, in the variable stiffness flexible operating arm described in this embodiment, as a preferred implementation:

[0077] like Figures 6 to 8 As shown, the thermal insulation sleeve 1 is defined as a cylinder, the multiple elastic straight tubes are evenly distributed in a ring shape, and the central axis of the cylindrical structure formed by the multiple elastic straight tubes arranged in a ring shape overlaps with the central axis of the thermal insulation sleeve; when an instrument passage 4 for conveying instruments is coaxially arranged in the cylindrical thermal insulation sleeve 1, the multiple elastic straight tubes are evenly distributed in the circumferential direction of the instrument passage 4.

[0078] In this embodiment, a plurality of elastic straight tubes are evenly distributed in the low-melting-point alloy layer 3 in a ring shape. When energy exchange fluid is introduced, the tubes have the characteristics of fast temperature rise / fall and good uniformity of thermal conductivity, thereby effectively ensuring the variable stiffness effect of the low-melting-point alloy layer.

[0079] Example 4: Figures 9 to 10 As shown, this embodiment is further improved on the basis of embodiment 3 as follows:

[0080] A plurality of elastic node disks 6 are connected to the plurality of elastic straight tubes arranged in a ring shape, and the outer peripheral wall of each of the elastic node disks 6 is in contact with the inner wall of the heat insulation sleeve 1 respectively.

[0081] Specifically, Figure 11 As shown, the elastic section disc 6 is provided with a plurality of straight tube mounting holes 61 matching the elastic straight tubes, and the elastic straight tubes are respectively embedded in the elastic section disc 6 through the straight tube mounting holes 61 .

[0082] In the flexible variable-rigidity operating arm described in this embodiment, the provision of a plurality of elastic node disks 6 can connect a plurality of elastic straight tubes into a curved whole, and each of the elastic node disks 6 is respectively abutted against the thermal insulation sleeve 1, which can better improve the bending curvature of the elastic skeleton (a plurality of elastic straight tubes) and create a prerequisite for improving the accuracy of the operating arm motion control.

[0083] Furthermore, as a preferred embodiment, a number of the elastic joint discs 6 are connected at equal intervals to a plurality of elastic straight pipes, and a number of liquid metal flow grooves 62 are respectively provided on each of the elastic joint discs. Among them: the arrangement of a number of liquid metal flow grooves 62 on the elastic joint disc 6 is conducive to the better realization of the internal liquid circulation flow in the state of heating and melting of the low melting point alloy layer, and further conducive to further improving the rigid-flexible conversion effect and increasing the rigid-flexible conversion efficiency.

[0084] Example 5: As Figures 12 to 15 shown, on the basis of Example 1 of the present invention, another variable stiffness flexible manipulator is provided, which is different from Examples 2 to 4 in that:

[0085] As Figure 12 shown, the external pipelines 5 for fluid input and output are respectively arranged on the proximal end plug 11 and the distal end plug 12; the elastic skeleton 2 is provided with a fluid circulation channel 21 by itself, and the fluid circulation channel 21 is respectively communicated with the external pipelines 5 arranged on the sealing end plugs at both ends of the heat insulation sleeve 1 to realize fluid circulation.

[0086] Among them: according to the different types of the elastic skeleton 2, the variable stiffness flexible manipulator in this embodiment mainly has the following three structural forms:

[0087] (1) As Figure 13 shown, it is defined that the elastic skeleton 2 includes at least one elastic straight pipe with a fluid circulation channel 21 by itself. One end of the elastic straight pipe is communicated with the external pipeline 5 through the proximal end plug 11, and the other end is communicated with the external pipeline through the distal end plug 12;

[0088] The proximal end plug 11 and the distal end plug 12 have the same structural settings, and respectively include an installation pipe hole for assembling the elastic straight pipe and a liquid chamber communicated with the elastic straight pipe and the external pipeline 5. Installation interfaces connected to the external pipeline 5 are respectively arranged on the liquid chambers;

[0089] One end of the elastic straight pipe is fixed on the proximal end plug 11 by means of adhesive fixation, and the other end is movably embedded in the installation pipe hole on the distal end plug 12; at the same time, the assembly gap between the installation pipe hole on the distal end plug 12 and the elastic straight pipe should ensure that the elastic straight pipe can slide while preventing the outflow of liquid metal or the inflow of circulating medium into the low melting point alloy layer.

[0090] (2) As Figure 14 shown, it is defined that the elastic skeleton 2 is composed of a plurality of elastic straight pipes with fluid circulation channels 21 by themselves, and the plurality of elastic straight pipes are uniformly arranged along the circumferential direction;

[0091] Furthermore, as a preferred embodiment, the heat insulation sleeve 1 is defined as a cylinder, and the central axis of the cylindrical structure formed by enclosing a plurality of the elastic straight pipes uniformly along the circumferential direction overlaps with the central axis of the heat insulation sleeve. A plurality of elastic joint discs 6 are connected to the plurality of elastic straight pipes, and a plurality of liquid metal flow grooves 61 are provided on the elastic joint discs 6.

[0092] (3) As Figure 15 、 16 shown, the elastic framework 2 is defined as a single spiral elbow with a self - contained fluid circulation channel 21. One end of the single spiral elbow is connected to the external pipeline 5 through the proximal end plug 11, and the other end is connected to the external pipeline 5 through the distal end plug 12 to realize fluid circulation.

[0093] Among them: as Figure 16 shown, the inside of the single spiral elbow is hollow, and a fluid input conduit 22 and a fluid output conduit 23 are respectively arranged at both ends.

[0094] Furthermore, as a preferred embodiment, the heat insulation sleeve 1 is defined as a cylinder. An instrument through - tube 4 is coaxially arranged inside the cylindrical heat insulation sleeve 1, and the single spiral elbow is arranged around the instrument through - tube 4. Then, the elastic framework is located at the central position of the low - melting - point alloy layer 3. When an energy - exchange fluid is input into the single spiral elbow, the energy diffuses and transfers from the center inside the low - melting - point alloy layer to the periphery, thereby shortening the time of rigid - flexible transformation and improving the efficiency of rigid - flexible transformation.

[0095] In the variable - stiffness flexible manipulator of the present Example 5, the circulation mode of the fluid is as follows: The energy - exchange medium is input into the fluid circulation channel 21 of the elastic framework 2 through the external pipeline 5 arranged on the proximal end plug 11, and the energy - exchange medium is led out through the external pipeline 5 arranged on the distal end plug 12 to realize fluid circulation.

[0096] In addition, it should be noted that for the specific embodiments described in this specification, the shapes and names of their components can be different. Any equivalent or simple changes made according to the structure, features, and principles described in the inventive concept of this invention patent are included in the protection scope of this invention patent. Those skilled in the technical field to which this invention belongs can make various modifications, supplements, or use similar methods to replace the specific embodiments described, as long as they do not deviate from the structure of this invention or exceed the scope defined by this claim book, they should all belong to the protection scope of this invention.

Claims

1. A variable stiffness flexible manipulator, characterized in that, Comprising: A heat insulation sleeve, with sealing end plugs respectively arranged at both ends thereof; A low melting point alloy layer, filled and arranged inside the heat insulation sleeve; An elastic framework, arranged in the low melting point alloy layer, the elastic framework has its own fluid circulation channel, and the fluid circulation channel is communicated with an external pipeline through the sealing end plugs arranged at the ends of the heat insulation sleeve to realize fluid circulation; wherein: The sealing end plugs arranged at both ends of the heat insulation sleeve are respectively a proximal end plug and a distal end plug; one end of the elastic framework is fixed on the proximal end plug, and the other end is movably embedded on the distal end plug; The elastic framework includes a plurality of elastic straight pipes with their own fluid circulation channels, and a liquid chamber communicated with the plurality of elastic straight pipes is arranged on the distal end plug. The plurality of elastic straight pipes are respectively communicated with an external pipeline through the proximal end plug to realize fluid circulation; the heat insulation sleeve is cylindrical, the plurality of elastic straight pipes are uniformly arranged along the circumferential direction, and the central axis of the cylindrical structure formed by enclosing the plurality of elastic straight pipes overlaps with the central axis of the heat insulation sleeve.

2. The variable stiffness flexible manipulator according to claim 1, wherein A plurality of elastic joint discs are connected and arranged on the plurality of elastic straight pipes uniformly arranged along the circumferential direction, and the outer peripheral walls of the respective elastic joint discs are respectively in contact with the inner wall of the heat insulation sleeve.

3. The variable stiffness flexible manipulator according to claim 2, wherein A plurality of liquid metal flow grooves are respectively arranged on the respective elastic joint discs.

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