Deformation and bearing integrated modular rope-driven flexible mechanical arm and self-sensing method thereof

Abstract

The invention discloses a deformation and bearing integrated modular rope-driven flexible mechanical arm and a self-sensing method thereof.The flexible mechanical arm comprises a driving mechanism and a variable-rigidity flexible mechanical arm body, the variable-rigidity flexible mechanical arm body comprises a rope, a corrugated pipe and elastic units, and the multiple elastic units are filled in an inner cavity of the corrugated pipe; the corrugated pipe is provided with a rope guide hole extending in the axial direction of the corrugated pipe, one end of the rope is fixedly connected with the power output end of the driving mechanism, the other end of the rope penetrates through the rope guide hole and is fixedly connected with the corrugated pipe, and when the driving mechanism works, the rope can be driven to move, and then the mechanical arm is pulled to deform. The flexibility of the mechanical arm is improved through fusion of active deformation and a bearing function, additional rigid structure supporting is not needed, and the overall design is simplified; and the bearing capacity and rigidity are adaptively improved through blocking of the elastic units, and the complexity of the driving system is reduced. Meanwhile, the mechanical arm is provided with a self-sensing system, the state of the mechanical arm can be monitored in real time, and the control precision is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of mechanical arms, and particularly relates to a modularized rope-driven flexible mechanical arm with deformation and load bearing integration and a self-sensing method thereof. BACKGROUND

[0002] With the continuous progress of science and technology, mechanical arms are applied in many industries such as agriculture, military industry, firefighting, and logistics. Traditional rigid mechanical arms have high structural stiffness and strong load bearing capacity, but are heavy in weight and high in inertia, and are difficult to be safely applied in complex, narrow or closely collaborative environments with people. In contrast, flexible mechanical arms are light in weight, small in inertia and high in compliance, and can adapt to complex environments and achieve safe human-machine interaction, but have problems such as limited load bearing capacity, insufficient structural stiffness and insufficient control precision.

[0003] Flexible mechanical arms have significant advantages in human-machine collaboration, space operation, medical treatment, rescue and dangerous environment operation due to their light weight and small inertia, and have become one of the important research directions in the field of robots in recent years. Among them, rope-driven flexible mechanical arms have attracted widespread attention due to their simple structure, high compliance and easy control.

[0004] However, existing rope-driven flexible mechanical arms use ropes to drive flexible structures to achieve active deformation, but the stiffness of the flexible structure is low, and the load bearing capacity is obviously insufficient, which is difficult to meet the actual load demand. In the existing technical solutions, the structural load bearing capacity is mainly improved by adding rigid supports, designing rigid-flexible coupling and adjusting the stiffness. Although the mechanical arms directly adding rigid supports and rigid-flexible coupling improve the load bearing capacity of the structure to some extent, they also limit the flexibility and degrees of freedom of the mechanical arm, and increase the inertia and weight of the system; the stiffness-variable mechanical arm achieves stiffness adjustment through particle blocking, vacuum pumping and redundant drive, among which the vacuum pump and the rigid structure of the redundant drive increase the overall weight of the structure, and the existing particle blocking method is often combined with vacuum pumping and other methods, which increases the structural load bearing capacity but also increases the structural weight. At the same time, too many rope drive designs lead to high system complexity and control difficulty, and the motion precision and response speed are obviously limited, which has obvious shortcomings in engineering practical applications.

[0005] In addition, the modular design can enable the structural components of the mechanical arm to be quickly assembled, and multiple mechanical arms can increase the motion range and dexterity, which is widely used in rigid mechanical arms, but the use in flexible mechanical arms will increase the structural weight, and how to balance the compliance control and lightweight design of the flexible arm is a big problem. SUMMARY

[0006] The present application aims to provide a modularized rope-driven flexible manipulator with deformation and load bearing integration and a self-sensing method thereof, and aims to solve the problems of complex structure, serious driving redundancy and insufficient load bearing capacity of existing rope-driven flexible manipulators.

[0007] In a first aspect of the present application, a modularized rope-driven flexible manipulator with deformation and load bearing integration is provided, comprising a driving mechanism and a variable stiffness flexible manipulator, the variable stiffness flexible manipulator comprising a rope, a bellows and an elastic unit, the elastic unit being filled in an inner cavity of the bellows, the bellows being provided with a rope guide hole extending in an axial direction thereof, one end of the rope being fixedly connected with a power output end of the driving mechanism, the other end of the rope passing through the rope guide hole and being fixedly connected with the bellows, the driving mechanism being capable of driving the rope to move when working, thereby pulling the bellows to deform.

[0008] In some implementations, the driving mechanism comprises a first driving mechanism and a second driving mechanism, the rope comprises a circumferential rope located at a periphery of the bellows and a central rope located at a central position of the bellows, a power output end of the first driving mechanism being fixedly connected with the circumferential rope, a power output end of the second driving mechanism being fixedly connected with the central rope.

[0009] In some implementations, the modularized rope-driven flexible manipulator comprises at least two sections of the variable stiffness flexible manipulator, and adjacent two sections of the variable stiffness flexible manipulator are detachably connected through a quick release device; each section of the variable stiffness flexible manipulator is controlled to move and deform by a plurality of circumferential ropes and a central rope, each section of the variable stiffness flexible manipulator is provided with a plurality of rope guide holes, and the plurality of rope guide holes are spaced apart in a circumferential direction of the variable stiffness flexible manipulator; in each section of the variable stiffness flexible manipulator, each rope is matched with a driving mechanism.

[0010] In some implementations, the quick release device comprises a manipulator bottom connecting piece, a manipulator top connecting piece, a sliding block and a spring, the manipulator bottom connecting piece being fixed at a bottom end of one section of the variable stiffness flexible manipulator, and the manipulator top connecting piece being fixed at a top end of another section of the variable stiffness flexible manipulator.

[0011] The manipulator top connecting piece is internally provided with two symmetrically distributed mounting grooves, and the sliding block and the spring are embedded in the mounting grooves; the sliding block has a pressing head, a spring clamping groove and a limiting boss, an avoiding opening is formed in a wall body of the manipulator top connecting piece, the pressing head protrudes out of the avoiding opening, an outer end of the spring is embedded in the spring clamping groove, and an inner end of the spring abuts against an inner groove wall of the mounting groove; a clamping groove is formed at a bottom end of the manipulator bottom connecting piece, the spring abuts against the sliding block, and the limiting boss is clamped into the clamping groove when there is no external thrust; when the pressing head is pressed, the limiting boss can be disengaged from the clamping groove.

[0012] In some implementations, the variable stiffness flexible robot arm further comprises a shaft hollow tube installed at the center of the bellows and extending along the axial direction thereof; the edges of the robot arm top connector and the robot arm bottom connector are provided with a plurality of circumferential small holes for the circumferential ropes to pass through, and the middle part of the robot arm top connector and the robot arm bottom connector is provided with a central small hole for the central rope to pass through, and the central rope passes through the shaft hollow tube and the central small hole and is fixedly connected with the robot arm bottom connector.

[0013] In some implementations, the variable stiffness flexible robot arm further comprises a robot arm end base fixedly connected with the end of the bellows of a section of the variable stiffness flexible robot arm, and the edges of the robot arm end base are provided with a plurality of circumferential small holes for the circumferential ropes to pass through, and the middle part of the robot arm end base is provided with a central small hole for the central rope to pass through, and the central rope is fixedly connected with the robot arm end base.

[0014] In some implementations, the other end of the bellows is in the shape of a truncated cone, the top of the robot arm bottom connector is provided with a conical groove, the other end of the bellows is embedded in the conical groove and fixedly connected with the robot arm bottom connector.

[0015] In the second aspect of the present application, a self-sensing method of a modular rope-driven flexible robot arm is provided, wherein the elastic deformation unit in the robot arm comprises elastic particles, the outer surface of the elastic particles is covered with a conductive coating, and the inner cavity of each section of the bellows is provided with a conductive layer at both ends; the self-sensing method comprises:

[0016] The elastic particles filled in the bellows are in contact with each other to form a flexible piezoresistive sensor that can deform with the bellows, and different bending states and different compression states can cause the elastic particles inside to be extruded, resulting in a change in resistance;

[0017] The conductive layers on both sides of the bellows are in sufficient contact with the hollow particles, are connected to be powered on, and are transmitted to an upper computer through wires, the upper computer collects multiple groups of data, trains the data, performs machine learning, and realizes self-sensing of the flexible robot arm.

[0018] In the second aspect of the present application, a self-sensing method of a modular rope-driven flexible robot arm is provided, wherein the elastic deformation unit in the robot arm comprises rigid particles and an elastic reset structure, the elastic reset structure is installed at the periphery of the rigid particles, and the elastic reset structure comprises a compression spring made of metal and a plug head; the self-sensing method comprises:

[0019] The bellows is extruded by the elastic deformation unit before and after deformation, the structural rigidity is enhanced by increasing the friction between the rigid particles, the rigidity is coupled with the deformation, the rope is released, and the thrust of the elastic deformation unit can quickly reset the bellows;

[0020] The two ends of the compression spring are connected with wires, the compression spring forms an inductance sensor after being connected with the power supply, the inductance sensor is connected with an LC resonant circuit, different deformation states of the flexible bellows mechanical arm correspond to different extrusion and blockage states of the rigid particles, the compression spring is extruded to different degrees, the inductance sensor changes correspondingly, and thus the resonant frequency changes, the frequency detection module reads the frequency change, and the deformation state of the flexible mechanical arm corresponding to the current spring compression amount is further inferred.

[0021] In a third aspect, the self-sensing method of the modular rope-driven flexible mechanical arm is provided, wherein the elastic deformation unit in the mechanical arm comprises rigid particles and an elastic reset structure, the elastic reset structure is mounted on the periphery of the rigid particles, and the elastic reset structure comprises a compression spring made of metal and conductive foam; and the self-sensing method comprises the following steps:

[0022] When pressure is applied to the conductive foam, the overall resistance becomes smaller, the conductive foam is connected with wires at both ends and is electrified, and the conductive foam serves as a variable resistor with variable resistance with pressure;

[0023] When the bellows is bent and deformed in different ways, the rigid particles and the conductive foam are extruded to different degrees, the overall structural rigidity is improved, the current in the circuit changes to different degrees, each current corresponds to a different deformation state of the bellows, the relationship between the current and the deformation of the bellows can be obtained after a plurality of experiments, and then the state of the flexible mechanical arm is obtained through the current.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] The present application provides a deformation and load integrated modular rope-driven flexible mechanical arm, which comprises a driving mechanism and a variable rigidity flexible mechanical arm, the variable rigidity flexible mechanical arm comprises a rope, a bellows and elastic hollow particles, the hollow particles are filled in the inner cavity of the bellows, one end of the rope is fixedly connected with the power output end of the driving mechanism, and the other end is fixedly connected with the bellows; the driving mechanism can drive the rope to move when the driving mechanism works, and then the variable rigidity flexible mechanical arm is deformed. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a three-dimensional structural schematic diagram of a modular rope-driven flexible manipulator provided by Embodiment One of the present application;

[0027] Figure 2 is Figure 1 is an internal structural schematic diagram of a system console in the modular rope-driven flexible manipulator shown in

[0028] Figure 3 is a cross-sectional schematic diagram of a single-section variable-stiffness flexible manipulator provided by Embodiment One of the present application;

[0029] Figure 4 is a three-dimensional structural schematic diagram of a single-section bellows provided by Embodiment One of the present application;

[0030] Figure 5a is a configuration schematic diagram of a rope on a first-section variable-stiffness flexible manipulator;

[0031] Figure 5b is a configuration schematic diagram of a rope on a second-section variable-stiffness flexible manipulator;

[0032] Figure 5c is a configuration schematic diagram of a rope on a third-section variable-stiffness flexible manipulator;

[0033] Figure 6 is Figure 1 is a schematic diagram of the modular rope-driven flexible manipulator shown in

[0034] Figure 7 is Figure 1 is a schematic diagram of the modular rope-driven flexible manipulator shown in

[0035] Figure 8 is a three-dimensional structural schematic diagram of a quick-release device provided by Embodiment One of the present application;

[0036] Figure 9 is Figure 8 is an exploded structural schematic diagram of the quick-release device shown in

[0037] Figure 10 is Figure 8 is a three-dimensional structural schematic diagram of a manipulator top connecting piece in the quick-release device shown in

[0038] Figure 11 is Figure 8 is an internal structural schematic diagram of the quick-release device shown in

[0039] Figure 12 is Figure 8 is a three-dimensional structural schematic diagram of a sliding block in the quick-release device shown in

[0040] Figure 13 is Figure 8 is a perspective view of the mechanical arm bottom connecting piece in the quick release device shown in

[0041] Figure 14 is Figure 8 is a perspective view of the mechanical arm top connecting piece in the quick release device shown in

[0042] Figure 15 is Figure 8 is a perspective view of the mechanical arm bottom connecting piece in the quick release device shown in

[0043] Figure 16 is Figure 8 is a perspective view of the mechanical arm end base in the quick release device shown in

[0044] Figure 17 is a cross-sectional view of the hollow particle provided by the embodiment one of the present application;

[0045] Figure 18 is a self-sensing sensing diagram of the variable stiffness flexible mechanical arm provided by the embodiment one of the present application;

[0046] Figure 19 is a self-sensing operation flowchart of the variable stiffness flexible mechanical arm provided by the embodiment one of the present application;

[0047] Figure 20 is a flexible mechanical arm system block diagram of the variable stiffness flexible mechanical arm provided by the embodiment one of the present application.

[0048] Explanation of reference signs:

[0049] System console 10, drive mechanism 11, steering wheel 111, roller 112, steering wheel turntable 113, mounting base 12, variable stiffness flexible mechanical arm 20, bellows 21, hollow particle 22, conductive coating 221, rope guide hole 211, circumferential rope 23a, central rope 23b, mechanical arm connecting boss 24, shaft center hollow pipe 25, mechanical arm end base 26, conductive layer 27, flexible piezoresistive sensor 28, wire 29, quick release device 30, mechanical arm bottom connecting piece 31, clamping groove 311, conical groove 312, mechanical arm top connecting piece 32, mounting groove 321, avoiding port 322, embedding groove 323, hollow channel 324, sliding block 33, pressing head 331, spring clamping groove 332, limiting boss 333, spring 34, circumferential small hole 3a, central small hole 3b, fixed small hole 3c. DETAILED DESCRIPTION

[0050] In order to make the inventive purposes, features and advantages of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the following described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0051] In the description of the present application, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application; the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance; in addition, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two components. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0052] The technical solutions of the present application will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0053] Embodiment one:

[0054] Please refer to Figure 1 , which shows the overall structure of a modularized rope-driven flexible manipulator provided by the embodiment one, the modularized rope-driven flexible manipulator includes a system console 10 and at least two sections of variable stiffness flexible manipulators 20, wherein, please refer to Figure 2 , which is a schematic view of the internal structure of the system console 10, the system console 10 includes a driving mechanism 11 and a mounting base 12, and the driving mechanism 11 is mounted on the mounting base 12. Please refer to Figure 3 , which shows the structure of a single section of variable stiffness flexible manipulator, each section of variable stiffness flexible manipulator 20 includes a rope, a bellows 21 and elastic hollow particles 22, and the hollow particles 22 are filled in the inner cavity of the bellows 21. Please refer to Figure 4, shows the structure of a single section of corrugated tube, the periphery of the corrugated tube 21 and the intermediate position of both ends are provided with a rope guide hole 211 extending along its axial direction, one end of the rope is fixedly connected with the power output end of the driving mechanism 11, the other end passes through the rope guide hole 211 and is fixedly connected with the corrugated tube 21, when the driving mechanism 11 works, it can drive the rope to move, and then pull the corrugated tube 21 to deform. The above-mentioned elastic hollow particles 22 can allow larger deformation of the structure, after the structure is deformed, the hollow particles 22 are extruded, the friction between the hollow particles 22 is increased, and then the overall stiffness of the mechanical arm is increased. In addition, the hollow particles 22 can greatly reduce the structural mass, so that the mechanical arm is more light and has better flexibility. In other embodiments, elastic solid particles can also be used. In order to facilitate the deformation and recovery of the corrugated tube 21, the corrugated tube 21 is preferably made of a material with strong elastic properties, and in this embodiment, the corrugated tube 21 is made of TPU material and is made by selective laser forming 3D printing.

[0055] Specifically, the driving mechanism of the present embodiment includes a first driving mechanism and a second driving mechanism, each driving mechanism includes a steering gear 111, a roller 112 and a steering gear turntable 113, the steering gear 111 is fixed on the mounting base 12, the steering gear turntable 113 is in transmission connection with the steering gear 111, the roller 112 is rotatably installed on the mounting base 12, the rope is arranged on the roller 112, the steering gear 111 is rotated to drive the rope to move, and then pull the variable stiffness flexible mechanical arm to move and deform.

[0056] Further, please refer to Figure 3 The rope of the present embodiment includes a circumferential rope 23a located on the periphery of the corrugated tube 21 and a central rope 23b located at the central position of the corrugated tube 21, the power output end of the first driving mechanism is fixedly connected with the circumferential rope 23a, and the power output end of the second driving mechanism is fixedly connected with the central rope 23b. In each section of the variable stiffness flexible mechanical arm, each rope is matched with a driving mechanism. It should be noted that the above only lists one of the optional driving mechanisms, and other forms of driving structure can also be used in actual application, for example, a swing structure can be used to pull the rope.

[0057] Please refer to Figure 5a to Figure 5c , shows the configuration of the rope on each section of the variable stiffness flexible mechanical arm, it can be seen that each section of the corrugated structure is controlled to move and deform by 3 circumferential ropes 23a, therefore, n sections of variable stiffness flexible mechanical arms can be configured according to the task requirements, in order to independently control each section of the variable stiffness flexible mechanical arm, it is necessary to provide the circumferentially distributed rope guide holes 211 for all the variable stiffness flexible mechanical arms, 3n rope guide holes 211 are needed for n sections of the mechanical arms, wherein each circumferential rope 23a and the rope guide hole 211 are uniformly arranged in the circumferential direction of the corrugated tube 21.

[0058] For the convenience of description, the embodiment takes a 3-section variable stiffness flexible manipulator as an example, which is provided with 9 rope guide holes 211 to arrange the circumferential ropes 23a in space. As shown in Figure 3 , each layer of the manipulator only needs 3 evenly distributed circumferential ropes 23a for control, such as the circumferential ropes 23a for driving the second layer of the manipulator need to pass through the rope guide holes 211 of the first layer, and the circumferential ropes 23a for driving the third layer of the manipulator need to pass through the rope guide holes 211 of the first and second layers. Each section of the manipulator is driven and controlled by 3 circumferential ropes, and different circumferential ropes 23a drive different displacements to achieve 360° omnidirectional bending deformation, as shown in Figure 6 , which is a structural schematic diagram of the overall structure bending state of the modular rope-driven flexible manipulator. As shown in Figure 7 , which is the initial unbending state of the modular rope-driven flexible manipulator, wherein the bellows of the manipulator is in a hollow corrugated shape, which can realize deformation such as folding, bending and compression.

[0059] As shown in Figure 6 , the two adjacent sections of the variable stiffness flexible manipulator 20 are detachably connected through the quick release device 30; please refer to Figure 8 and Figure 9 , which shows a quick release device provided by the embodiment, the quick release device 30 includes a manipulator bottom connecting piece 31, a manipulator top connecting piece 32, a sliding block 33 and a spring 34. The manipulator bottom connecting piece 31 is fixed at the bottom end of one section of the variable stiffness flexible manipulator 20, and the manipulator top connecting piece 32 is fixed at the top end of another section of the variable stiffness flexible manipulator 20.

[0060] Please refer to Figure 10 and Figure 11 , the manipulator top connecting piece 32 is internally provided with two symmetrically distributed mounting grooves 321, and the sliding block 33 and the spring 34 are embedded in the mounting grooves 321; please refer to Figure 12 , which shows the structure of the sliding block 33 provided by the embodiment, the sliding block 33 has a pressing head 331, a spring clamping groove 332 and a limiting boss 333, the wall body of the manipulator top connecting piece 32 is provided with an avoiding opening 322, the pressing head 331 protrudes out of the avoiding opening 322, the outside end of the spring 34 is embedded in the spring clamping groove 332, and the inside end of the spring 34 abuts against the inside groove wall of the mounting groove 321; please refer to Figure 13, shows the structure of the mechanical arm bottom connecting piece 31 provided by the embodiment, the bottom end of the mechanical arm bottom connecting piece 31 is provided with a clamping groove 311, the avoiding opening 322 is matched with the pressing head 331 in shape, and the sliding block 33 is allowed to slide in the direction of the avoiding opening 322. When there is no external thrust, the spring 34 tightly presses the sliding block 33, the limiting boss 333 is clamped into the clamping groove 311, at this time, the two sections of the variable stiffness flexible mechanical arm 20 are fixedly connected with each other, when the pressing head 331 is pressed, the limiting boss 333 can be separated from the clamping groove 311, at this time, the two sections of the variable stiffness flexible mechanical arm 20 can be separated.

[0061] It can be seen that the quick release device is used to realize the quick assembly and separation of the two sections of the variable stiffness flexible mechanical arm 20, and the manufacturing and maintenance costs are low, and the structure is simple.

[0062] As shown in Figure 3 and Figure 4 , the variable stiffness flexible mechanical arm further includes a mechanical arm connecting boss 24, a shaft hollow pipe 25 and a mechanical arm end base 26, the mechanical arm connecting boss 24 is fixedly connected at one end of the bellows pipe 21 (which can be integrally formed with the bellows pipe), and is used to be fixedly connected with the bottom of the mechanical arm top connecting piece 32, in the embodiment, please refer to Figure 14 , a structural diagram of the mechanical arm top connecting piece 32 provided by the embodiment, the bottom of the mechanical arm top connecting piece 32 is provided with an annular embedding groove 323 and a hollow channel 324, the mechanical arm connecting boss 24 is embedded and fixed in the embedding groove 323, the hollow channel 324 limits the position of the shaft hollow pipe 25, but allows the shaft hollow pipe 25 to slide in the channel. The other end of the bellows pipe 21 is in the form of a conical frustum, please refer to Figure 15 , the top of the mechanical arm bottom connecting piece 31 is provided with a conical groove 312, and the other end of the bellows pipe 21 is embedded in the conical groove 312 and fixedly connected with the mechanical arm bottom connecting piece 31.

[0063] The shaft hollow pipe 25 is installed at the central position of the bellows pipe 21 and extends in the axial direction. The edges of the mechanical arm top connecting piece 32 and the mechanical arm bottom connecting piece 31 are respectively provided with a plurality of circumferential small holes 3a for the circumferential rope 23a to pass through, and the middle positions of the mechanical arm top connecting piece 32 and the mechanical arm bottom connecting piece 31 are provided with a central small hole 3b for the central rope 23b to pass through, the central rope 23b passes through the shaft hollow pipe 25 and the central small hole 3b and is fixedly connected with the mechanical arm bottom connecting piece 31.

[0064] The mechanical arm end base 26 is fixedly connected with the end of the bellows pipe 21 of the one section of the variable stiffness flexible mechanical arm 20, please refer to Figure 16, shows the structure of the mechanical arm end base 26, the edge of which is provided with a plurality of circumferential small holes 3a for the circumferential rope 23a to pass through, and the middle position of the mechanical arm end base 26 is provided with a central small hole 3b for the central rope 23b to pass through, and the central rope 23b is fixedly connected with the mechanical arm end base 26.

[0065] In order to realize the fixation of the end of the circumferential rope 23a with the mechanical arm bottom connecting piece 31 or the mechanical arm end base 26, please refer to Figure 13 and Figure 16 The bottom of the mechanical arm bottom connecting piece 31 and the bottom of the mechanical arm end base 26 are provided with fixed small holes 3c at positions corresponding to the circumferential small holes 3a, and the circumferential rope 23a can be fixed by embedding a fixing piece or glue in the fixed small hole.

[0066] Through the above structural design, each variable stiffness flexible mechanical arm is controlled by 4 ropes, of which 3 circumferential ropes 23a evenly distributed in the circumferential direction control the structural movement, and the bending and compression deformation occur. The elastic hollow particles 22 are used inside for filling, and the particles are rearranged when the structure is deformed. Due to the space reduction, the particles are extruded, and the structural stiffness is improved. When the single-joint mechanical arm completes the deformation, the central rope 23b is driven to make the structure further compressed, and the hollow particles 22 inside are further extruded, increasing the friction between the particles, and further increasing the stiffness of the whole structure, improving the carrying capacity of the mechanical arm. When the structure is deformed, the bending deformation and compression deformation of the structure are coupled with the stiffness of the structure, and the control of the central rope 23b after deformation can further increase the stiffness of the mechanical arm, so as to decouple the stiffness and deformation.

[0067] Further, the mechanical arm bottom connecting piece 31, the mechanical arm top connecting piece 32, the quick release device, the sliding block 33 and the mechanical arm end base of the embodiment are all made of PLA material 3D printing. This kind of material has low density and light weight, so that the mechanical arm structure is light and flexible as a whole.

[0068] In order to make the mechanical arm have self-sensing ability, the self-sensing system is arranged in the mechanical arm, please refer to Figure 17 , which is a cross-sectional view of the hollow particle 22. The hollow particle 22 is a hollow structure, and the outer surface is covered with a conductive coating 221, such as conductive ink. Please refer to Figure 18 , which is a self-sensing sensing diagram of the variable stiffness flexible mechanical arm. The inner cavity of each bellows 21 is provided with a conductive layer 27 at both ends, and the hollow particles 22 filled in the bellows 21 are in contact with each other, forming a flexible piezoresistive sensor 28 which can deform with the bellows 21. Please refer to Figure 19 , which is a self-sensing operation flow chart of the flexible mechanical arm. Please refer to Figure 20Fig. 2 is a control system block diagram of the flexible robot arm; the computer sends control signals to the FE-URT circuit control board through the control program, the FE-URT circuit control board controls the rotation of each servo 111, the servo 111 tightens and relaxes the rope, thereby controlling the posture change and stiffness change of the flexible robot arm, driving the circumferential rope 23a to change the posture and cooperate with the deformation of the robot arm, and driving the central rope 23b to further improve the stiffness and decouple the stiffness. In this process, the different bending states and different compression states of the deformation driving module (i.e. the bellows 21) can cause the hollow particles 22 of the stiffness self-sensing module (i.e. the flexible piezoresistive sensor 28) to be extruded (different compression states represent different stiffness of the robot arm), causing the resistance to change, the conductive layer 27 on both sides of the bellows 21 and the hollow particles 22 to be in full contact, connected to the power supply, and transmitted to the host computer (i.e. the computer) through the wire 29. The host computer collects multiple sets of data, trains the data, and performs machine learning to monitor the state (such as bending state, stiffness state) of the robot arm in real time, thereby achieving precise control of the structure of the robot arm.

[0069] Example Two

[0070] This embodiment provides a second self-sensing system for the flexible robot arm. In terms of structure, the self-sensing system is different from that of Example One in that the elastic deformation unit of this embodiment includes rigid particles and an elastic reset structure, which is installed on the periphery of the rigid particles, for example, on the left and right sides, the top and bottom sides, or the four sides. For example, the elastic reset structure of this embodiment includes a compression spring made of metal and a plug head, one end of the compression spring is embedded in the plug head, and the other end abuts against the compression spring; in other embodiments, other forms of elastic reset structures can also be used.

[0071] The bellows is extruded by the elastic deformation unit before and after deformation, the structural stiffness is enhanced by increasing the friction between the rigid particles, the stiffness is coupled with the deformation, and the rope is released. The thrust of the elastic deformation unit can quickly reset the bellows.

[0072] The two ends of the compression spring are connected to wires, and the compression spring connected to the power supply forms an inductance sensor, which is connected to an LC resonant circuit. Different deformation states of the flexible bellows robot arm correspond to different extrusion and plugging states of the rigid particles, which will extrude the compression spring to different degrees, the inductance sensor will change accordingly, thereby causing the resonant frequency to change, the frequency detection module reads the frequency change, and further infers the deformation state of the flexible robot arm corresponding to the current spring compression amount.

[0073] Example Three

[0074] The third self-sensing system is provided for the flexible mechanical arm, and the difference between the self-sensing system and the first embodiment is that the elastic deformation unit of the embodiment comprises rigid particles and an elastic reset structure, the elastic reset structure is installed on the periphery of the rigid particles, and the elastic reset structure comprises a compression spring made of metal and conductive foam; the conductive foam is a material doped with conductive materials (such as carbon, metal fibers, graphite, etc.) in a flexible and porous structure, which not only has soft compressibility, but also has variable resistance characteristics, and is therefore very suitable for making flexible pressure or tactile sensors. When pressure is applied to the conductive foam, the overall resistance will decrease.

[0075] When pressure is applied to the conductive foam, the overall resistance will decrease, wires are connected at both ends of the conductive foam to be electrified, and the conductive foam acts as a variable resistor with variable resistance with pressure.

[0076] When the bellows undergo different bending deformation and compression deformation, the rigid particles and the conductive foam are also extruded to different degrees, the overall structural stiffness is improved, and the current in the circuit changes to different degrees, each current corresponds to a different deformation state of the bellows, and the relationship between the current and the deformation of the bellows can be obtained after a plurality of experiments, and then the state of the flexible mechanical arm is obtained through the current.

[0077] In summary, the modular rope-driven flexible mechanical arm of the embodiment keeps the structure flexible and compliant and has high degrees of freedom through the modular design of the plurality of mechanical arm modules, does not need additional rigid structural support, simplifies the overall design, monitors the real-time state through self-sensing, improves the control accuracy, adaptively improves the carrying capacity and the stiffness through the blocking stiffness of the elastic unit, improves the structural carrying capacity without the need to increase additional driving and structure, reduces the complexity of the driving system, and significantly improves the overall performance and practicality of the flexible mechanical arm.

[0078] The above only describes the preferred embodiments of the present application and should not be used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A modular, rope-driven, flexible robotic arm with integrated morphing load bearing, characterized by, The variable stiffness flexible robot arm comprises a driving mechanism and a variable stiffness flexible robot arm, the variable stiffness flexible robot arm comprises a rope, a bellows and an elastic deformation unit, a plurality of the elastic deformation units are filled in the inner cavity of the bellows, the bellows is provided with a rope guide hole extending along the axial direction, one end of the rope is fixedly connected with the power output end of the driving mechanism, the other end passes through the rope guide hole and is fixedly connected with the bellows, and the driving mechanism can drive the rope to move when working, thereby pulling the bellows to deform.

2. The modular rope-driven flexible manipulator of claim 1, wherein, The driving mechanism comprises a first driving mechanism and a second driving mechanism, the rope comprises a circumferential rope located at the periphery of the bellows and a central rope located at the central position of the bellows, the power output end of the first driving mechanism is fixedly connected with the circumferential rope, and the power output end of the second driving mechanism is fixedly connected with the central rope.

3. The modular, rope-driven, flexible manipulator of claim 2, wherein, The variable stiffness flexible robot arm comprises at least two sections of the variable stiffness flexible robot arm, and adjacent two sections of the variable stiffness flexible robot arm are detachably connected through a quick release device; each section of the variable stiffness flexible robot arm is controlled to move and deform by a plurality of circumferential ropes and a central rope, each section of the variable stiffness flexible robot arm is provided with a plurality of rope guide holes, and the plurality of rope guide holes are spaced apart along the circumferential direction of the variable stiffness flexible robot arm; in each section of the variable stiffness flexible robot arm, each rope is matched with a driving mechanism.

4. The modular, rope-driven, flexible manipulator of claim 3, wherein, The quick release device comprises a robot arm bottom connecting piece, a robot arm top connecting piece, a sliding block and a spring, the robot arm bottom connecting piece is fixed at the bottom end of one section of the variable stiffness flexible robot arm, and the robot arm top connecting piece is fixed at the top end of another section of the variable stiffness flexible robot arm. The robot arm top connecting piece is internally provided with two symmetrically distributed mounting grooves, and the sliding block and the spring are embedded in the mounting grooves; the sliding block has a pressing head, a spring clamping groove and a limiting boss, an avoiding opening is formed in the wall body of the robot arm top connecting piece, the pressing head protrudes out of the avoiding opening, the outer end of the spring is embedded in the spring clamping groove, and the inner end of the spring abuts against the inner groove wall of the mounting groove; the bottom end of the robot arm bottom connecting piece is provided with a clamping groove, the spring abuts against the sliding block when there is no external thrust, the limiting boss is clamped into the clamping groove, and the limiting boss can be separated from the clamping groove when the pressing head is pressed.

5. The modular, rope-driven, flexible manipulator of claim 4, wherein, The variable stiffness flexible robot arm further comprises a shaft center hollow pipe, the shaft center hollow pipe is installed at the central position of the bellows and extends along the axial direction thereof; the edges of the robot arm top connecting piece and the robot arm bottom connecting piece are provided with a plurality of circumferential small holes through which the circumferential ropes pass, and the central position of the robot arm top connecting piece and the robot arm bottom connecting piece is provided with a central small hole through which the central rope passes, the central rope passes through the shaft center hollow pipe and the central small hole and is fixedly connected with the robot arm bottom connecting piece.

6. The modular, rope-driven, flexible manipulator of claim 5, wherein, The variable stiffness flexible robot arm further comprises a robot arm end base fixedly connected with an end of the bellows of the variable stiffness flexible robot arm, edges of the robot arm end base are provided with a plurality of circumferential small holes for the circumferential ropes to pass through, and a central small hole for the central rope to pass through is arranged at a middle position of the robot arm end base, and the central rope is fixedly connected with the robot arm end base.

7. The modular, rope-driven, flexible manipulator of claim 4, wherein, The other end of the bellows is in the form of a frustum, a top of the robot arm bottom connector is provided with a conical groove, the other end of the bellows is embedded in the conical groove, and the other end of the bellows is fixedly connected with the robot arm bottom connector.

8. The self-aware method of a modular rope-driven flexible manipulator according to any one of claims 1 to 7, wherein, The elastic deformation unit comprises elastic particles, an outer surface of the elastic particle is covered with a conductive coating, and both ends of the inner cavity of each bellows are provided with a conductive layer; the self-sensing method comprises: The elastic particles filled in the bellows are in contact with each other to form a flexible piezoresistive sensor which can deform with the bellows, different bending states and different compression states can cause the elastic particles inside to be extruded, resulting in a change in resistance; The conductive layers on both sides of the bellows are in sufficient contact with the hollow particles, are connected to be powered on, and are transmitted to an upper computer outside through wires, the upper computer collects multiple groups of data, trains the data, performs machine learning, and realizes self-sensing of the flexible robot arm.

9. A self-aware method of a modular rope-driven flexible manipulator as claimed in any one of claims 1 to 7, characterized in that, The elastic deformation unit comprises rigid particles and an elastic reset structure, the elastic reset structure is installed around the rigid particles, the elastic reset structure comprises a compression spring made of metal and a plug head; the self-sensing method comprises: The bellows is extruded by the elastic deformation unit before and after deformation, the structural stiffness is enhanced by increasing the friction between the rigid particles, the stiffness is coupled with the deformation, the ropes are released, and the thrust of the elastic deformation unit can quickly reset the bellows; Both ends of the compression spring are connected with wires, the compression spring forms an inductance sensor after being connected to a power source, the inductance sensor is connected to an LC resonant circuit, different deformation states of the flexible bellows correspond to different extrusion and plugging states of the rigid particles, the compression spring is extruded to different degrees, the inductance sensor changes correspondingly, thereby causing a change in the resonant frequency, a frequency detection module reads the change in the frequency, and further infers the deformation state of the flexible robot arm corresponding to the current spring compression amount.

10. A self-aware method of a modular rope-driven flexible manipulator as claimed in any one of claims 1 to 7, characterized in that, The elastic deformation unit comprises rigid particles and an elastic reset structure, the elastic reset structure is installed around the rigid particles, the elastic reset structure comprises a compression spring made of metal and a conductive foam; the self-sensing method comprises: When pressure is applied to the conductive foam, the overall resistance becomes smaller, wires are connected to both ends of the conductive foam to be powered on, and the conductive foam serves as a variable resistor which changes with the pressure; When the bellows undergoes different bending deformation and compression deformation, the rigid particles and the conductive foam are also extruded to different degrees, the overall structural stiffness is improved, and the current in the circuit changes to different degrees, each current corresponds to a different deformation state of the bellows, and the relationship between the current and the deformation of the bellows can be obtained after multiple experiments, and then the state of the flexible mechanical arm is obtained through the current.

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