A fiber-driven flexible manipulator and its cell and rigidity control method

Abstract

The application belongs to the technical field of mechanical hands, and particularly discloses a flexible mechanical hand driven by an optical fiber, a cell of the flexible mechanical hand and a rigidity control method, wherein the flexible finger of the flexible mechanical hand is composed of a plurality of flexible cells which are fixedly connected in sequence; the flexible cell comprises a plurality of flexible cell skeletons, a plurality of flexible hinges and a shell reinforced optical fiber; the flexible cell skeleton and the flexible hinge are alternately connected in sequence in the circumferential direction, and the plurality of flexible cell skeletons are connected into a polygonal hollow column structure through the flexible hinge; at least one shell reinforced optical fiber is connected in at least one flexible cell; one end of the shell reinforced optical fiber is fixedly connected to one of the two flexible hinges, and the other end is fixedly connected to the other of the two flexible hinges, so as to control the deformation of the overall structure by adjusting the diagonal length of the flexible cell, and the displacement and stress of the flexible cell are collected in real time. The problems of poor stability, complex control, poor sensing ability and poor dexterity of the traditional flexible mechanical hand are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of manipulators, and in particular relates to an optical fiber-driven flexible manipulator and a cell and stiffness control method thereof. Background Art

[0002] Flexible manipulators are a type of robot made of soft materials that can effectively perform grasping and manipulation tasks in unstructured environments. Compared to traditional rigid manipulators, flexible manipulators have more degrees of freedom and better adaptability, and are therefore widely used in industries such as industry, agriculture, and medicine. However, due to their soft material composition, flexible manipulators generally suffer from poor stability and complex control algorithms. Furthermore, flexible manipulators are currently primarily used for grasping tasks, making dexterous in-hand manipulation difficult. Therefore, it is crucial to design a method that combines stiffness control and deformation sensing to improve the stability and dexterity of flexible manipulators.

[0003] Flexible manipulators with variable stiffness can exhibit good compliance when in contact with objects, while also demonstrating good stability in performing tasks. Blocking mechanisms and smart material actuation are both methods for stiffness control of traditional flexible manipulators. Among them, the stiffness control method based on the blocking mechanism utilizes the interaction between different structural parts of the flexible manipulator. According to the working principle, it can be divided into two categories: one is to change its own stiffness by blocking with particles such as rice grains and coffee grains, which is the particle blocking method; the other is to set a blocking layer in the flexible manipulator and change the stiffness by utilizing the antagonistic effect between the blocking layer and the driving layer, such as using air pressure drive, which is the layer blocking method. The method based on smart material actuation utilizes the fact that the mechanical properties of certain materials are easily affected by the external environment, such as the thermal effect of the material. Smart materials commonly used for stiffness control of flexible manipulators include low-melting-point alloys, shape memory alloys, dielectric elastomers, supercoiled polymers, etc.

[0004] With the rapid development and application of robotics technology, people have put forward higher requirements on the perception ability and dexterity of end effectors.

[0005] On the one hand, to enable robotic arms to perceive their surroundings, a common design approach involves using visual or ultrasonic sensors to collect environmental information, thereby assisting the manipulator in positioning and manipulation. On the other hand, to achieve dexterous in-hand manipulation capabilities, traditional design methods include utilizing friction mechanisms or adding mechanical structures. Methods utilizing friction mechanisms typically involve re-regulating the manipulator's surface friction, which is related to the friction coefficient and normal load. Therefore, friction-based methods typically incorporate one or more variable-friction contact surfaces within the manipulator, leveraging the friction differences between the finger surfaces to achieve in-hand object movement. Furthermore, adding mechanical structures is another design approach. Adding linkages or pneumatic drive mechanisms to the manipulator are common design approaches. New mechanical structures can expand the manipulator's degrees of freedom and reconfigure its structure, thereby improving its range of motion and dexterity.

[0006] The existing technology has the following disadvantages:

[0007] 1. Traditional stiffness control methods for flexible manipulators: While simple in design, stiffness control methods based on blocking mechanisms have drawbacks such as requiring large amounts of material, high system costs, and poor controllability. Because smart materials require time to respond to external stimuli, these stiffness control methods are often too slow to respond. Furthermore, their applicability is limited.

[0008] 2. Methods to improve the perception capabilities of flexible manipulators: Perception methods based on visual sensors can provide high-resolution images, but visual sensors are very sensitive to light, which seriously affects the quality of the collected images; during the movement of the manipulator, visual sensors are easily blocked and lose their function; perception methods based on ultrasonic sensors can work under visually restricted conditions, but their resolution is too low, and the environmental adaptability of acoustic wave sensors is poor.

[0009] 3. Methods to improve the dexterity of flexible manipulators: Currently, methods based on friction mechanisms are usually applied to rigid manipulators and have not yet been maturely applied to flexible manipulators. Methods based on friction mechanisms are essentially the regulation of friction force, and have problems such as poor accuracy and complex design. Methods that increase mechanical structure have good response speed and accuracy, such as adding a connecting rod structure or a pneumatic drive mechanism, but have the disadvantages of complex structural design, difficulty in manufacturing, and complex control algorithms.

[0010] Therefore, it is urgent to design a new method that combines stiffness control and deformation sensing to increase the stability and dexterity of flexible manipulators. Summary of the Invention

[0011] In order to solve the problems of poor stability, complex control, poor perception and dexterity of traditional flexible manipulators, the present invention provides a fiber-driven flexible manipulator and a cell and stiffness control method thereof.

[0012] In order to achieve the above object, the present invention adopts the following specific technical solutions:

[0013] The present invention provides an optical fiber driven flexible manipulator, the flexible manipulator comprising flexible fingers;

[0014] The flexible finger is composed of a plurality of flexible cells that are fixedly connected in sequence;

[0015] The flexible cell comprises a plurality of flexible cell skeletons, a plurality of flexible hinges and a shell-reinforced optical fiber; the flexible cell skeletons and the flexible hinges are alternately connected in a circumferential direction, and the plurality of flexible cell skeletons are connected by the flexible hinges to form a polygonal hollow cylindrical structure;

[0016] At least one of the shell-reinforced optical fibers is connected in at least one of the flexible cells; one end of the shell-reinforced optical fiber is fixedly connected to one of the two relatively arranged flexible hinges, and the other end passes through the other of the two relatively arranged flexible hinges, and is used to control the deformation of the overall structure by adjusting the diagonal length of the flexible cell, and to collect the displacement and stress of the flexible cell in real time.

[0017] Furthermore, it also includes a motor corresponding to each of the shell-reinforced optical fibers; the motor is used to adjust the length of the shell-reinforced optical fibers between the two relatively arranged flexible hinges.

[0018] Furthermore, it also includes a control system;

[0019] The control system includes a main control board module, a drive module, an optical fiber sensor module, an electronic switch, and a DuPont cable; the main control board module is used to generate and transmit control instructions; the drive module is used to control the independent operation of each motor and continuously provide power to it; the optical fiber sensor module uses the shell-reinforced optical fiber as a path for optical signals to collect displacement and stress information of the flexible cell in real time and feed it back to the main control board module;

[0020] The control system controls the telescopic movement and tension change of the multiple shell-reinforced optical fibers according to the sensing information, thereby actively regulating the stiffness and deformation of the multiple flexible cells.

[0021] Furthermore, the cross-sectional shape of the polygonal hollow cylindrical structure is a quadrilateral or hexagonal symmetrical structure.

[0022] Further, when the cross-sectional shape of the polygonal hollow cylinder structure is a hexagonal symmetric structure, two of the shell-reinforced optical fibers are connected in the hexagonal symmetric structure.

[0023] Further, the flexible hinges and the flexible cell skeletons are made of deformable soft materials.

[0024] In addition, the present application also provides a flexible cell for the flexible robot arm, which comprises a plurality of flexible cell skeletons, a plurality of flexible hinges and shell-reinforced optical fibers.

[0025] The flexible cell skeletons and the flexible hinges are connected in sequence along the circumference, and the plurality of flexible cell skeletons are connected into a polygonal hollow cylinder structure through the flexible hinges.

[0026] At least one of the shell-reinforced optical fibers is connected in the polygonal hollow cylinder structure, one end of the shell-reinforced optical fiber is fixedly connected to one of the two oppositely arranged flexible hinges, and the other end passes through the other of the two oppositely arranged flexible hinges, so as to control the deformation of the overall structure by adjusting the diagonal length of the flexible cell and to collect the displacement and stress of the flexible cell in real time.

[0027] Further, when the cross-sectional shape of the polygonal hollow cylinder structure is a hexagonal symmetric structure, two of the shell-reinforced optical fibers are connected in the hexagonal symmetric structure.

[0028] Further, when the cross-sectional shape of the polygonal hollow cylinder structure is a hexagonal symmetric structure, two of the shell-reinforced optical fibers are connected in the hexagonal symmetric structure.

[0029] Meanwhile, the present application also provides a rigidity control method of the flexible cell, which adjusts the rigidity of the flexible cell by controlling the length of the shell-reinforced optical fiber in the polygonal hollow cylinder structure.

[0030] Meanwhile, the present application also provides a deformation sensing method of the flexible cell, which collects the displacement and stress of the flexible cell in real time by using the optical fiber sensor based on the shell-reinforced optical fiber, and obtains the deformation information of the flexible cell under external force.

[0031] Further, the optical fiber sensor is composed of a shell-reinforced optical fiber, a light generator, a light receiver, a sensitive element and a signal processing system; the optical fiber sensor can effectively sense the change of the internal light signal of the shell-reinforced optical fiber, and inversely calculate the displacement and stress of the flexible cell according to the optical effect; the optical fiber sensor is arranged in the interior of the flexible cell and directly contacts and connects with the flexible cell through a buffer structure.

[0032] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0033] The flexible fingers of the flexible manipulator of the present invention are composed of a plurality of flexible cells fixedly connected in sequence; the flexible cells are formed into a polygonal hollow cylindrical structure by alternatingly connecting a flexible cell skeleton and a flexible hinge in a circumferential direction; at least one shell-reinforced optical fiber is connected in at least one flexible cell; the diagonal length of the flexible cell can be adjusted through the shell-reinforced optical fiber to control the deformation of the overall structure to achieve stiffness regulation, and the displacement and stress of the flexible cell can be collected in real time, so that each flexible cell can independently regulate the stiffness and deformation, thereby realizing the dexterous operation function of the manipulator; through the coordinated work of multiple flexible cells, the flexible manipulator finger can realize a variety of deformation modes under different working conditions, including but not limited to grasping, moving, rotating, etc., and through flexible selection and combination of deformation modes, complex operation tasks can be completed.

[0034] The flexible manipulator of the present invention can be composed of flexible cells with different structural parameters. The mechanism of dexterous operation of the manipulator is realized by independently regulating the stiffness of each flexible cell. The stiffness of different areas of the flexible manipulator can be selectively adjusted. The displacement and stress data of the manipulator are collected in real time through the shell-reinforced optical fiber. The structure is simple to control, good environmental perception is achieved, and it has good compliance and controllability. It solves the problems of poor stability, complex control, poor perception ability and dexterity of traditional flexible manipulators. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 These are two structures of the flexible cell of the present invention;

[0036] Figure 2 It is a flexible porous manipulator composed of three flexible cells with different structural parameters;

[0037] Figure 3 This is a schematic diagram of the principle of the flexible porous manipulator of the present invention performing in-hand operation tasks. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] In order to solve the problems of poor stability, complex control, insufficient perception and dexterity of current traditional flexible manipulators, the present invention proposes a flexible manipulator based on optical fiber drive.

[0040] Example 1

[0041] like Figure 2 and Figure 3 As shown in the structure, this embodiment provides a fiber-driven flexible manipulator, which includes flexible fingers; the flexible fingers are composed of multiple flexible cells fixedly connected in sequence; the flexible cells include multiple flexible cell skeletons 1, multiple flexible hinges 2 and shell-reinforced optical fibers 3; the flexible cell skeletons 1 and the flexible hinges 2 are alternately connected in the circumferential direction, and the multiple flexible cell skeletons 1 are connected to form a polygonal hollow cylindrical structure through the flexible hinges 2; the two configurations of the flexible cells are as follows Figure 1 As shown, it has the functions of both stiffness adjustment and deformation sensing. At least one shell-reinforced optical fiber 3 is connected to at least one flexible cell; one end of the shell-reinforced optical fiber 3 is fixedly connected to one of the two oppositely arranged flexible hinges 2, and the other end passes through the other of the two oppositely arranged flexible hinges 2, which is used to control the deformation of the entire structure by adjusting the diagonal length of the flexible cell and to collect the displacement and stress of the flexible cell in real time. Figure 1 As shown, there is a shell-enhanced optical fiber 3 connected between points A and B, between points a and b, and between points c and d. Points A, B, a, b, c, and d are all flexible hinges 2, which have strong rigidity and flexibility. The shell-enhanced optical fiber 3 can be used as a driving device to actively adjust the length of the diagonal of the flexible cell and the deformation of the overall structure, that is, to regulate the rigidity of the flexible cell as a whole, and can also be used as an optical fiber sensor to collect the displacement and stress of the cell in real time. When the shell-enhanced optical fiber 3 is not loaded, the flexible cell will undergo a large deformation under the action of external force, resulting in the diagonal of the flexible cell (such as Figure 1 The length of the flexible cell (shown between A and B in FIG) becomes larger. However, when the shell-reinforced optical fiber 3 is in a load-bearing state, the flexible cell will undergo small deformation or almost no deformation when interacting with the outside world. In this process, the overall stiffness and stability of the flexible cell will be significantly enhanced. Therefore, the stiffness control method based on the drive of the shell-reinforced optical fiber 3 is essentially to achieve a change in the overall stiffness by controlling the deformation amount of the flexible cell. The shell-reinforced optical fiber 3 is a new type of optical fiber with a reinforced shell material, which has better flexibility and strength. The shell-reinforced optical fiber 3 serves as a channel for the propagation of optical signals in optical fiber sensors.

[0042] The flexible cell also includes motors and a control system corresponding to the outer shell-reinforced optical fibers 3. The motors are used to adjust the length of the outer shell-reinforced optical fibers between two opposing flexible hinges. The control system includes a main control board module, a driver module, a fiber optic sensor module, an electronic switch, and DuPont cables. The main control board module generates and transmits control commands. The driver module controls the independent operation of each motor and continuously provides them with power. The fiber optic sensor module uses the outer shell-reinforced optical fibers 3 as a pathway for optical signals to collect real-time displacement and stress information from the flexible cell and provide feedback to the main control board module. Based on the collected sensor information, the control system controls the expansion and contraction motion and tension changes of the multiple outer shell-reinforced optical fibers 3, thereby actively regulating the stiffness and deformation of the multiple flexible cells. By precisely adjusting the stiffness of different regions through the control system, the flexible manipulator has multiple stiffness control modes, such as unilateral and bilateral stiffness control, resulting in enhanced dexterity and intelligence, enabling operations such as translation and rotation of objects within the hand. The fiber optic sensor is a contact sensor, located within the flexible cell and directly connected to the cell via a buffer structure.

[0043] like Figure 1 As shown, the cross-sectional shape of the polygonal hollow cylindrical structure is a quadrilateral or hexagonal symmetrical structure. When the cross-sectional shape of the polygonal hollow cylindrical structure is a hexagonal symmetrical structure, two cross-shell reinforced optical fibers 3 are connected inside the polygonal hollow cylindrical structure. The flexible hinge and the flexible cell skeleton are both made of a deformable soft material.

[0044] Example 2

[0045] This embodiment provides a flexible cell for the flexible manipulator, such as Figure 1 As shown, the flexible cell includes multiple flexible cell skeletons, multiple flexible hinges, and shell-reinforced optical fibers. The flexible cell skeletons and flexible hinges are alternately connected along the circumference, and the multiple flexible cell skeletons are connected by the flexible hinges to form a polygonal hollow cylindrical structure. At least one shell-reinforced optical fiber is connected within the polygonal hollow cylindrical structure. One end of the shell-reinforced optical fiber is fixedly connected to one of two oppositely arranged flexible hinges, and the other end passes through the other of the two oppositely arranged flexible hinges. It is used to control the deformation of the entire structure by adjusting the diagonal length of the flexible cell and to collect the displacement and stress of the flexible cell in real time. When the cross-sectional shape of the polygonal hollow cylindrical structure is rectangular, one shell-reinforced optical fiber is connected within the rectangular hollow cylindrical structure. When the cross-sectional shape of the polygonal hollow cylindrical structure is a regular hexagon, two cross-shell-reinforced optical fibers are connected within the regular hexagonal hollow cylindrical structure.

[0046] The basic shape and structural parameters of the flexible cell can be freely designed, such as overall height and tilt angle. Based on the idea of ​​modularization, multiple flexible cells with different structural parameters are regularly assembled together to form an adaptive flexible robotic finger, such as Figure 2 As shown. Among them, Figure 2 There are a first shell-reinforced optical fiber 31 and a second shell-reinforced optical fiber 32, the positions and quantities of which can be freely designed; Figure 2 The first, second, and third flexible cells 11, 12, and 13 in the flexible porous manipulator have different structural parameters. Actively controlling the telescopic motion of the first and second outer shell-reinforced optical fibers 31, 32 (controlling the length changes of the outer shell-reinforced optical fibers) effectively adjusts the structural stiffness of different regions of the flexible porous manipulator finger.

[0047] In addition, multiple flexible fingers can be assembled into a flexible robot arm with universal structure. Figure 3 It is to assemble two flexible fingers into a flexible mechanical gripper. Figure 3 There are a third shell-reinforced optical fiber 33, a fourth shell-reinforced optical fiber 34, a fifth shell-reinforced optical fiber 35 and a sixth shell-reinforced optical fiber 36, and the above four shell-reinforced optical fibers are respectively arranged on single holes at different positions of the flexible finger; Figure 3 The flexible manipulator has a first flexible finger 14 and a second flexible finger 15 with adjustable stiffness. With the driving action of the third shell-enhanced optical fiber 33, the fourth shell-enhanced optical fiber 34, the fifth shell-enhanced optical fiber 35 and the sixth shell-enhanced optical fiber 36, the flexible manipulator can independently regulate the stiffness and deformation of four specific areas of the manipulator, thereby realizing the manipulator's dexterous operation functions, such as rotating and translating objects in the hand. In addition, the shell-enhanced optical fiber 3 can not only effectively control the stiffness of the flexible manipulator, but also serve as an optical fiber sensor to collect information such as displacement and stress in real time. It is worth mentioning that the size of the manipulator finger, the number of flexible cells, and the number and position of the shell-enhanced optical fiber 3 can all be set arbitrarily, with very good versatility.

[0048] Example 3

[0049] This embodiment provides a method for both stiffness control and deformation sensing of the aforementioned flexible cell. This stiffness control and deformation sensing method adjusts the stiffness of the flexible cell by controlling the length of the outer shell-reinforced optical fiber within a polygonal hollow cylindrical structure. Simultaneously, a fiber optic sensor based on the outer shell-reinforced optical fiber is used to collect the displacement and stress of the flexible cell in real time, thereby obtaining deformation information of the flexible cell under the action of external forces. The fiber optic sensor comprises an outer shell-reinforced optical fiber, a light generator, an optical receiver, a sensitive element, and a signal processing system. The fiber optic sensor can effectively sense changes in the optical signal within the outer shell-reinforced optical fiber and infer the displacement and stress of the flexible cell based on the optical effect. The fiber optic sensor is arranged within the flexible cell and is directly in contact with and connected to the flexible cell via a buffer structure.

[0050] The flexible fingers of the above-mentioned flexible manipulator are composed of multiple flexible cells fixedly connected in sequence; the flexible cells are formed into a polygonal hollow cylindrical structure by alternatingly connecting a flexible cell skeleton and a flexible hinge along the circumferential direction; at least one shell-reinforced optical fiber is connected in at least one flexible cell; the diagonal length of the flexible cell can be adjusted through the shell-reinforced optical fiber to control the deformation of the overall structure, and the displacement and stress of the flexible cell can be collected in real time, so that each flexible cell can independently regulate the stiffness and deformation, thereby realizing the dexterous operation function of the manipulator. Through the collaborative work of multiple flexible cells, the flexible robotic fingers can realize multiple deformation modes under different working conditions, including but not limited to grasping, moving, rotating, etc., and through flexible selection and combination of deformation modes, complex operation tasks can be completed.

[0051] The flexible manipulator of the present invention is composed of flexible cells with different structural parameters. The mechanism of dexterous operation of the manipulator is realized by independently regulating the stiffness of each flexible cell. The stiffness of different areas of the flexible manipulator can be selectively adjusted. The displacement and stress data of the manipulator are collected in real time through the shell-reinforced optical fiber. The structure is simple to control, good environmental perception is achieved, and it has good compliance and controllability. It solves the problems of poor stability, complex control, poor perception ability and dexterity of traditional flexible manipulators.

[0052] Obviously, those skilled in the art may make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the present invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims and their equivalents, the present invention is intended to include such modifications and variations.

Claims

1. A fiber-driven flexible manipulator, characterized in that: including flexible fingers; The flexible finger is composed of a plurality of flexible cells that are fixedly connected in sequence; The flexible cell comprises a plurality of flexible cell skeletons, a plurality of flexible hinges and a shell-reinforced optical fiber; the flexible cell skeletons and the flexible hinges are alternately connected in a circumferential direction, and the plurality of flexible cell skeletons are connected by the flexible hinges to form a polygonal hollow cylindrical structure; At least one of the shell-reinforced optical fibers is connected to at least one of the flexible cells; one end of the shell-reinforced optical fiber is fixedly connected to one of the two oppositely disposed flexible hinges, and the other end passes through the other of the two oppositely disposed flexible hinges, so as to control the deformation of the overall structure by adjusting the diagonal length of the flexible cell and collect the displacement and stress of the flexible cell in real time; The invention also includes a control system and a motor corresponding to each of the shell-enhanced optical fibers; the motor is used to adjust the length of the shell-enhanced optical fibers between the two relatively arranged flexible hinges; The control system includes a main control board module, a drive module and an optical fiber sensor module; the drive module is used to control the independent operation of each of the motors; The optical fiber sensor module uses the shell-reinforced optical fiber as a path for optical signals to collect displacement and stress information of the flexible cell in real time and feed it back to the main control board module; The control system controls the telescopic movement and tension change of the plurality of shell-enhanced optical fibers according to the collected sensing information.

2. The flexible manipulator according to claim 1, characterized in that: The control system further includes an electronic switch and a DuPont line; the main control board module is used to generate and transmit control instructions; the drive module is used to continuously provide power to each of the motors; The control system can actively regulate the stiffness and deformation of the plurality of flexible cells.

3. The flexible manipulator according to claim 1, characterized in that: The cross-sectional shape of the polygonal hollow cylindrical structure is a quadrilateral or hexagonal symmetrical structure; When the cross-sectional shape of the polygonal hollow cylindrical structure is a hexagonal symmetrical structure, two crossed shell-reinforced optical fibers are connected in the hexagonal symmetrical structure.

4. The flexible manipulator according to any one of claims 1 to 3, characterized in that: The flexible hinge and the flexible cell skeleton are both made of deformable soft materials.

5. A flexible cell, characterized in that: The flexible cell is used for an optical fiber-driven flexible manipulator as claimed in any one of claims 1 to 4, wherein the flexible cell comprises a plurality of flexible cell skeletons, a plurality of flexible hinges and a shell-reinforced optical fiber; The flexible cell skeleton and the flexible hinge are alternately connected in sequence along the circumferential direction, and a plurality of the flexible cell skeletons are connected by the flexible hinge to form a polygonal hollow cylindrical structure; At least one shell-reinforced optical fiber is connected in the polygonal hollow cylindrical structure; one end of the shell-reinforced optical fiber is fixedly connected to one of the two relatively arranged flexible hinges, and the other end passes through the other of the two relatively arranged flexible hinges, and is used to control the deformation of the overall structure by adjusting the diagonal length of the flexible cell, and to collect the displacement and stress of the flexible cell in real time.

6. The flexible cell according to claim 5, wherein: When the cross-sectional shape of the polygonal hollow cylindrical structure is rectangular, one of the shell-enhanced optical fibers is connected inside the polygonal hollow cylindrical structure; When the cross-sectional shape of the polygonal hollow cylindrical structure is a regular hexagon, two crossed shell-reinforced optical fibers are connected in the polygonal hollow cylindrical structure.

7. A stiffness control method, characterized in that: The stiffness control method is used for the flexible cell as claimed in claim 5 or 6, and the stiffness of the flexible cell is adjusted by controlling the length of the shell-reinforced optical fiber in the polygonal hollow cylindrical structure.

8. A deformation perception method, characterized in that: The deformation sensing method is used for the flexible cell as described in claim 5 or 6, using an optical fiber sensor based on a shell-enhanced optical fiber to collect the displacement and stress of the flexible cell in real time, and obtain the deformation information of the flexible cell under the action of external force.

9. The deformation sensing method according to claim 8, wherein: The optical fiber sensor is composed of a shell-reinforced optical fiber, a light generator, a light receiver, a sensitive element, and a signal processing system. The optical fiber sensor can effectively sense changes in the optical signal inside the shell-reinforced optical fiber and invert the displacement and stress of the flexible cell based on the optical effect. The optical fiber sensor is arranged inside the flexible cell and is in direct contact with and connected to the flexible cell through a buffer structure.

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