A multi-degree-of-freedom bending and stiffness decoupled control continuum device and method

Abstract

The application belongs to the technical field of machine manipulation, and specifically discloses a multi-degree-of-freedom bending and stiffness decoupling control continuum device and method. The device comprises a variable stiffness continuum unit and a driving tension assembly. The outside of the variable stiffness body unit is connected through a universal joint connecting unit. The driving tension assembly corresponds to the universal joint connecting unit one by one. Adjacent variable stiffness continuum units are connected by adsorption to form a multi-section structure. The driving tension assembly comprises a first driving line rope and a second driving line rope. The first driving line rope and the second driving line rope are arranged in an antagonistic manner. The application adopts the above-mentioned multi-degree-of-freedom bending and stiffness decoupling control continuum device and method. Through the collaborative design of the particle blockage mechanism and the universal joint structure, the decoupling control of multi-directional bending deformation and stiffness adjustment is realized. The system structure is simplified, and the response speed and control accuracy are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of machine manipulation, in particular to a multi-degree-of-freedom bending and stiffness decoupling control continuum device and method. BACKGROUND

[0002] In the prior art, the continuum robot variable stiffness technology, including shape memory alloy (SMA), low melting point alloy (LMPA), mechanical "lock joint", etc., generally has the following problems:

[0003] 1. Strong control coupling: stiffness adjustment and deformation control are coupled, and independent regulation and control are difficult to achieve.

[0004] 2. Complex structure: high manufacturing cost, not conducive to miniaturization and integration.

[0005] 3. Lack of multi-directional collaborative control: it is difficult to achieve collaborative control of multi-directional bending and stiffness. SUMMARY

[0006] The purpose of the present application is to provide a multi-degree-of-freedom bending and stiffness decoupling control continuum device and method, which realizes decoupling control of multi-directional bending deformation and stiffness adjustment through the collaborative design of particle blocking mechanism and universal joint structure, simplifies the system structure, and improves the response speed and control accuracy.

[0007] To achieve the above purpose, the present application provides a multi-degree-of-freedom bending and stiffness decoupling control continuum device, which comprises a variable stiffness continuum unit and a driving tension assembly, the outside of the variable stiffness body unit is connected through a universal joint connecting unit, the driving tension assembly corresponds to the universal joint connecting unit one by one, and the adjacent variable stiffness continuum units are connected by adsorption to form a multi-segment structure.

[0008] The driving tension assembly comprises first driving lines and second driving lines, the first driving lines and the second driving lines are arranged in an antagonistic manner, and at least four first driving lines and second driving lines are respectively provided along the length direction of the universal joint connecting unit.

[0009] Preferably, the end of the variable stiffness continuum unit is provided with a magnet connection port, and the magnet connection port is provided with an embedded magnet.

[0010] Preferably, the variable stiffness continuum unit comprises a continuum (connected by a universal joint connection unit) and a variable stiffness body located in the center of the continuum, the continuum comprises two end connectors, a plurality of ring-shaped shafts, a plurality of intermediate connectors and a plurality of pins, the center of the end connector and the intermediate connector is provided with a protruding annular clamping groove, the protruding annular clamping groove is fixedly connected with the variable stiffness body, the end connector and the intermediate connector are connected by the pins penetrating the annular shafts arranged in cross.

[0011] Preferably, the periphery of the end connector and the intermediate connector is provided with a wire rope driving hole, and the first driving wire rope and the second driving wire rope are located in the wire rope driving hole.

[0012] Preferably, the variable stiffness body comprises a support column, an outer sealing film, a woven mesh, a particle filling layer, a metal corrugated hose, a sealing gasket, a sealing upper end cover and a sealing lower end cover, the outer sealing film is fixed to the outer surface of the support column by a tie, and the periphery of the outer sealing film is sequentially provided with the woven mesh, the particle filling layer and the metal corrugated hose, the two ends of the metal corrugated hose are embedded with the sealing gasket and the sealing upper end cover and the sealing lower end cover respectively, and the sealing upper end cover is provided with an air pipe connecting port in communication with the support column.

[0013] Preferably, the outer sealing film is a composite structure composed of a TPU film and a textile fabric.

[0014] Preferably, the particle filling layer is specifically filled with micro solid particles, such as coffee powder or glass beads.

[0015] Preferably, the support column comprises a spherical hinge connection upper end, a spherical hinge connection lower end, a plurality of soft connection films and a plurality of spherical hinge connection middle ends, the spherical hinge connection upper end and the spherical hinge connection middle end are provided with a vent hole for adding lubricating oil.

[0016] The bottom of the spherical hinge connection upper end and the spherical hinge connection middle end is provided with an annular protrusion, and the inside of the soft connection film is provided with an annular recess, and the spherical hinge connection upper end and the spherical hinge connection middle end are sealingly connected with the soft connection film through the annular protrusion and the recess, such as using a sealant or glue.

[0017] Preferably, the spherical hinge connection upper end and the spherical hinge connection lower end are provided with an annular sealing port for filling a sealant.

[0018] The application provides a multi-degree-of-freedom bending and stiffness decoupling control method, comprising the following steps:

[0019] S1, initial state: the inside of the variable stiffness body is normal air pressure, the solid particles can move freely, and the whole continuum device is in a flexible state;

[0020] S2, movement stage: by driving the tensioning assembly to control the first driving line rope and the second driving line rope, the specified variable stiffness continuum unit is bent to the target position;

[0021] S3, stiffness locking stage: after reaching the target position, the gas pipe connection port position of the variable stiffness body of the specified variable stiffness continuum unit is filled with positive pressure gas, triggering the particle blocking effect, so that the stiffness is significantly increased, and the shape is locked;

[0022] S4, cooperative work: after the shape of one variable stiffness continuum unit is locked, it can be used as a base to control the movement of another adjacent variable stiffness continuum unit, and then lock the shape thereof, so that the whole body is controlled in a complex environment through segmented and timed movement and stiffness control.

[0023] Therefore, the continuum device and method for multi-degree-of-freedom bending and stiffness decoupling control have the following beneficial effects:

[0024] The present application has high integration and simplified control: the combination of particle blocking and mechanical driving reduces the dependence on a complex external pneumatic system, and the system is more compact and responds faster.

[0025] The present application has multi-degree-of-freedom and decoupling control: the universal joint structure realizes multi-directional bending, and the bending movement and stiffness adjustment can be independently controlled, with high flexibility.

[0026] The present application has a large stiffness adjustment range: based on the particle blocking effect, the stiffness can be continuously and quickly switched in a wide range, with flexibility during operation and rigidity during stability.

[0027] The present application has a lightweight and durable structure: the use of soft materials, particle filling and lightweight structure makes the whole weight light and the impact resistance good, which is suitable for sensitive scenes such as medical treatment and detection.

[0028] The present application has high control precision: the combination of the constant curvature kinematics model and the stiffness analytical model provides a theoretical basis for the precise control of the robot. Through the cooperative design of the particle blocking mechanism and the universal joint structure, the decoupling control of multi-directional bending deformation and stiffness adjustment is realized, the system structure is simplified, and the response speed is improved.

[0029] The technical solutions of the present application will be further described in detail below through the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is the overall structure schematic diagram of the embodiment one of the present application;

[0031] Figure 2 is a local enlarged sectional view of A in the embodiment one of the present application;

[0032] Figure 3 is a local enlarged view of B in the embodiment one of the present application;

[0033] Figure 4 is a schematic view of the overall structure of the variable stiffness continuum unit in the embodiment one of the present application;

[0034] Figure 5 is a partial exploded view of the continuum in the embodiment one of the present application;

[0035] Figure 6 is a schematic view of the overall structure of the variable stiffness body in the embodiment one of the present application;

[0036] Figure 7 is an internal sectional view of the variable stiffness body in the embodiment one of the present application;

[0037] Figure 8 is a local enlarged view of C in the embodiment one of the present application;

[0038] Figure 9 is a partial exploded view of the support column in the embodiment one of the present application.

[0039] Reference signs

[0040] 1, first variable stiffness continuum; 2, second variable stiffness continuum; 3, wire rope lock; 4, first driving wire rope; 5, second driving wire rope;

[0041] 6, variable stiffness body; 6-1, embedded magnet; 6-2, magnet connection port; 6-3, metal corrugated hose; 6-4, sealed lower end cover; 6-5, sealed upper end cover; 6-6, support column; 6-7, air pipe connection port; 6-8, tie; 6-9, outer sealing film; 6-10, sealing gasket; 6-11, woven mesh; 6-12, granular filler layer; 6-13, vent hole; 6-14, spherical hinge connection upper end; 6-15, soft connection film; 6-16, spherical hinge connection middle end; 6-17, annular protrusion; 6-18, annular depression; 6-19, spherical hinge connection lower end; 6-20, annular sealing port.

[0042] 7, continuum; 7-1, end connector; 7-2, protruding annular clamping groove; 7-3, annular shaft; 7-4, middle connector; 7-5, pin; 7-6, wire rope driving hole. DETAILED DESCRIPTION

[0043] The technical solutions of the present application are further described below by means of the accompanying drawings and embodiments.

[0044] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0045] Example 1

[0046] like Figures 1-3 As shown, a continuum device for decoupling bending and stiffness control of multiple degrees of freedom includes a first variable stiffness continuum 1, a second variable stiffness continuum 2, at least four first drive cables 4, and at least four second drive cables 5. The first variable stiffness continuum 1 and the second variable stiffness continuum 2 are identical single variable stiffness continuum units based on particle blockage and universal joint structures, which can be stacked in a continuum design to form a multi-segment structure. An embedded magnet 6-1 is provided at the bottom of the first variable stiffness continuum 1, and similarly, an embedded magnet 6-1 is provided at the corresponding position at the end of the second variable stiffness continuum 2. The embedded magnets 6-1 at the ends of the first variable stiffness continuum 1 and the second variable stiffness continuum 2 are tightly attracted to form a combined body.

[0047] The first drive rope 4 and the second drive rope 5 form a drive tensioning assembly, enabling independent segmental control of the assembly. The assembly has at least eight rope drive hole paths along its length. At least four first drive ropes 4 pass through these paths and are secured by rope locks 3. Similarly, at least four second drive ropes 5 pass through these paths and are secured by rope locks 3. Using a cable drive system, each joint segment is equipped with at least two (or more) drive ropes arranged in an antagonistic manner. By differentially controlling the drive ropes (i.e., one tightens while the other relaxes), bending motion of the joint segment can be achieved without backlash. Multiple ropes working together allow for multi-degree-of-freedom bending of the continuous body. Each drive rope segment can be independently controlled, enabling segmented motion.

[0048] like Figure 4 As shown, the first variable stiffness continuum 1 includes a continuum 7 (composed of universal joint connecting units) and a variable stiffness body 6. The continuum 7 and the variable stiffness body 6 are interlocked through their own structure, with the variable stiffness body 6 located at the internal center of the continuum 7. Specifically, as... Figure 5As shown, the continuum 7 includes two end connectors 7-1, several annular shafts 7-3, several intermediate connectors 7-4, and several pins 7-5. The center of each end connector 7-1 and intermediate connector 7-4 is provided with a protruding annular groove 7-2, which is used to fix the variable stiffness body 6. At least eight cable drive holes 7-6 are provided through the periphery of each end connector 7-1 and intermediate connector 7-4, which are used to arrange drive cables. Adjacent end connectors 7-1 and intermediate connectors 7-4 or adjacent intermediate connectors 7-4 are arranged in a crisscross pattern and connected to the annular shafts 7-3 by pins 7-5. The connection points of the end connectors 7-1, intermediate connectors 7-4, annular shafts 7-3 and pins 7-5 are all smoothed. The annular shafts 7-3 and the two intermediate connectors 7-4 are staggered to form a universal joint connection unit, so that the continuum 7 can perfectly perform the function of a universal joint.

[0049] like Figures 6-9 As shown, the variable stiffness body 6 includes a support column 6-6, an outer sealing membrane 6-9, a braided mesh 6-11, a particle filling layer 6-12, a metal corrugated hose 6-3, a sealing gasket 6-10, a sealing upper end cap 6-5, and a sealing lower end cap 6-4. The support column 6-6 is located at the internal center, providing core support for the entire variable stiffness body 6. The outer sealing membrane 6-9 has a composite layer structure, surrounding and adhering to the outer surface of the support column 6-6, and is tightly bound by cable ties 6-8, forming a centrally sealed, pressurized, inflatable space. In this embodiment, the outer sealing membrane 6-9 is made of a composite of TPU film and textile fabric, possessing both airtightness and mechanical properties.

[0050] The outer wall of the outer sealing membrane 6-9 is wrapped with a braided mesh 6-11 to limit excessive expansion of the outer sealing membrane 6-9. The particle filling layer 6-12 is located in the gap between the braided mesh 6-11 and the metal corrugated hose 6-3. When the sealed space inside the outer sealing membrane 6-9 is inflated, the air pressure causes the outer sealing membrane 6-9 to expand outward. The particle filling layer 6-12 uses solid particles. Under the action of air pressure, the solid particles change from a loose state to a tightly packed state, resulting in a particle interlocking effect, which significantly improves the stiffness, thereby changing the entire variable stiffness body from a flexible state to a rigid state. At the same time, the inward air pressure further strengthens the stiffness of the central supporting spine. In this embodiment, the solid particles are micro-particles, specifically coffee powder, micro glass spheres, or other hard solid particles.

[0051] Two ends of the metal corrugated hose 6-3 are respectively embedded with a sealing upper end cover 6-5 and a sealing lower end cover 6-4 through a sealing gasket 6-10, so as to prevent solid particles from flowing out. The surface of the sealing lower end cover 6-4 and the sealing upper end cover 6-5 is provided with a magnet connection port 6-2, which is used for fixing an embedded magnet 6-1. In addition, the sealing upper end cover 6-5 is provided with an air pipe connection port 6-7, which is connected with a support column 6-6. The outer layer of the sealing film 6-9 is inflated outward by applying positive pressure gas to the inner cavity of the outer layer of the sealing film 6-9 through the air pipe connection port 6-7.

[0052] Specifically, the support column 6-6 includes a spherical hinge connection upper end 6-14, a spherical hinge connection lower end 6-19, a plurality of soft connection membranes 6-15 (TPE / TPU / silicone), and a plurality of spherical hinge connection middle ends 6-16. The spherical hinge connection upper end 6-14, the spherical hinge connection middle end 6-16, the soft connection membrane 6-15, and the spherical hinge connection lower end 6-19 are all universal joint connection units. A spherical universal joint is used to replace a traditional cross shaft universal joint. This structure allows the connection components to rotate in multiple directions, avoids hinge gaps and local stress concentration, and realizes smooth and precise multi-degree-of-freedom bending.

[0053] The spherical hinge connection upper end 6-14 and the spherical hinge connection middle end 6-16 are both provided with a ventilation hole 6-13. The ventilation hole 6-13 is used for adding lubricating oil to increase the flexibility of the support column 6-6 as a whole. The bottom of the spherical hinge connection upper end 6-14 and the spherical hinge connection middle end 6-16 is provided with an annular protrusion 6-17. The inside of the soft connection membrane 6-15 is provided with an annular recess 6-18. The spherical hinge connection upper end 6-14 and the spherical hinge connection middle end 6-16 are connected with the annular recess 6-18 of the soft connection membrane 6-15 through the annular protrusion 6-17. After the spherical hinge connection components (including the spherical hinge connection upper end 6-14, the spherical hinge connection middle end 6-16, and the spherical hinge connection lower end 6-19) are sequentially connected, an appropriate amount of lubricating oil is injected to enhance flexibility. The spherical hinge connection upper end 6-14 and the spherical hinge connection lower end 6-19 are both provided with an annular sealing port 6-20, which is sealed by filling a sealing agent into the annular sealing port 6-20 to obtain the support column 6-6 as a whole.

[0054] In addition, the variable stiffness continuum unit is a lightweight structure. In the present embodiment, the optional materials include aluminum alloy, carbon fiber composite material, or engineering plastic, etc.

[0055] Embodiment Two

[0056] A multi-degree-of-freedom bending and stiffness decoupling control method, which adopts the continuum device of embodiment one, combines the existing constant curvature kinematics model and stiffness analysis model, and specifically includes the following steps:

[0057] S1, initial state: the inside of the variable stiffness body 6 is normal air pressure, the solid particles can move freely, and the whole continuum device is in a flexible state.

[0058] S2, movement stage: by driving the tensioning assembly to control the first driving line rope 4 and the second driving line rope 5, the specified variable stiffness continuum unit is bent to the target position.

[0059] S3, stiffness locking stage: after reaching the target position, the gas pipe connection port 6-7 of the variable stiffness body 6 of the specified variable stiffness continuum unit is filled with positive pressure gas, triggering the particle blocking effect, so that the stiffness is significantly increased, and the shape is locked.

[0060] S4, cooperative work: after the shape of one variable stiffness continuum unit is locked, it can be used as a base to control the movement of the adjacent another variable stiffness continuum unit, and then lock the shape. Through segmented and timed movement and stiffness control, the multi-directional bending and stiffness decoupling control of the whole body in a complex environment is finally realized.

[0061] Therefore, the continuum device and method for multi-degree-of-freedom bending and stiffness decoupling control are adopted, the decoupling control of multi-directional bending deformation and stiffness adjustment is realized through the cooperative design of the particle blocking mechanism and the universal joint structure, the system structure is simplified, and the response speed and control accuracy are improved.

[0062] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application but not to limit it, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that: the technical solutions of the present application can still be modified or replaced by the equivalent, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A continuum device for multi-degree-of-freedom bending and stiffness decoupled control, characterized by: The variable stiffness continuum unit is connected to the outside through a universal joint connecting unit, and a driving tension assembly is correspondingly arranged with the universal joint connecting unit, and adjacent variable stiffness continuum units are connected by adsorption to form a multi-section structure. The driving tension assembly comprises first driving lines and second driving lines, the first driving lines and the second driving lines are arranged in an antagonistic manner, and at least four first driving lines and second driving lines are arranged along the length direction of the universal joint connecting unit. The end of the variable stiffness continuum unit is provided with a magnet connection port, and the magnet connection port is provided with an embedded magnet. The variable stiffness continuum unit comprises a continuum and a variable stiffness body located in the center of the continuum, the continuum comprises two end connectors, a plurality of ring shafts, a plurality of intermediate connectors and a plurality of pins, the centers of the end connectors and the intermediate connectors are provided with protruding ring clamping grooves, the protruding ring clamping grooves are fixedly connected with the variable stiffness body, the end connectors and the intermediate connectors are connected through the pins penetrating the ring shafts and cross arrangement, and the ring shafts and two intermediate connectors are connected in an interlaced manner to form a universal joint connecting unit. The variable stiffness body comprises a support column, an outer sealing film, a woven mesh, a particle filling layer, a metal corrugated hose, a sealing gasket, a sealing upper end cover and a sealing lower end cover, the outer sealing film is fixed to the outer surface of the support column by a strap, the outer periphery of the outer sealing film is sequentially provided with the woven mesh, the particle filling layer and the metal corrugated hose, the two ends of the metal corrugated hose are embedded with the sealing gasket and the sealing upper end cover and the sealing lower end cover respectively, the sealing upper end cover is provided with an air pipe connecting port, and the air pipe connecting port is communicated with the support column. The multi-degree-of-freedom bending and stiffness decoupling control method comprises the following steps: S1, initial state: the inside of the variable stiffness body is normal air pressure, the solid particles can move freely, and the whole continuum device is in a flexible state; S2, motion stage: control the first driving lines and the second driving lines through the driving tension assembly to bend the specified variable stiffness continuum unit to the target position; S3, stiffness locking stage: after reaching the target position, the air pipe connecting port of the specified variable stiffness continuum unit is filled with positive pressure gas, triggering the particle blocking effect, so that the stiffness is significantly increased, and the shape is locked; S4, cooperative work: after the shape of one variable stiffness continuum unit is locked, it can be used as a base to control the motion of another adjacent variable stiffness continuum unit, and then lock its shape, so as to realize the multi-directional bending and stiffness decoupling control of the whole body in complex environment through segmented and time-sharing motion and stiffness control.

2. A continuum device with multi-degree-of-freedom bending and stiffness decoupled control according to claim 1, wherein: The outer periphery of the end connector and the intermediate connector is provided with a line driving hole, and the first driving line and the second driving line are located in the line driving hole.

3. A continuum device with multi-degree-of-freedom bending and stiffness decoupled control according to claim 2, wherein: The outer sealing film is a composite structure composed of TPU film and textile fabric.

4. The multi-DOF bending and stiffness decoupled control continuum device of claim 2, wherein: The particle filling layer is filled with micro solid particles.

5. The multi-DOF bending and stiffness decoupled control continuum device of claim 2, wherein: The support column comprises a spherical hinge connected upper end, a spherical hinge connected lower end, a plurality of soft connection membranes and a plurality of spherical hinge connected middle ends, the spherical hinge connected upper end and the spherical hinge connected middle end are both provided with a vent hole for adding lubricating oil; The spherical hinge connected upper end and the bottom of the spherical hinge connected middle end are both provided with an annular protrusion, the inside of the soft connection membrane is provided with an annular recess, the spherical hinge connected upper end and the spherical hinge connected middle end are sealed and connected with the soft connection membrane through the annular protrusion and the recess.

6. A continuum device with multi-degree-of-freedom bending and stiffness decoupled control according to claim 5, wherein: The spherical hinge connected upper end and the spherical hinge connected lower end are both provided with an annular sealing port for filling a sealing agent.

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