Spherical cage-type flexible variable stiffness continuum robot unit and continuum robot

Abstract

A ball-cage-type flexible variable stiffness continuum robot unit and a continuum robot are disclosed. In the ball-cage-type flexible variable stiffness continuum robot unit, the main structural units are interconnected to form a continuum robot arm; joint connection structures connect adjacent main structural units; the front unit is located at the front end of the robot arm; and the rear unit is located at the rear end of the robot arm. In use, a ball-cage joint design is adopted, with each joint having two degrees of freedom, making it more flexible and adaptable. Adjacent structural units rotate around the center of the sphere, making modeling simpler. A flexible spring connection design is also used to provide a certain stiffness to the robot arm and give it variable stiffness characteristics. At the same time, the ball bearing structure gives it strong torsional resistance and can withstand large torsional loads. A through hole is opened in the center of the robot arm to accommodate various operating tools, enabling it to better adapt to perform tasks in different environments.

Description

Technical Field

[0001] This invention relates to the field of continuous robot technology, and in particular to a ball cage type flexible variable stiffness continuous robot unit and a continuous robot. Background Technology

[0002] Continuum robots are an emerging type of robotics technology inspired by the soft tissue structures within living organisms, such as elephant trunks and snakes. Compared to traditional rigid robots, continuum robots possess high flexibility and deformability, enabling them to mimic the movement and adaptability of living organisms. This gives them unique advantages and application potential in many fields, including search, aerospace, and medicine.

[0003] The structural units of a continuous robot arm are crucial components of the entire continuous robot, and their performance directly impacts the robot's applications. Currently, the structural design of continuous robot arms still faces some shortcomings and challenges. Traditional dual-core robots, such as the structure used in the invention patent "A Line-Driven Continuous Robot" (Publication No. CN 111168658 A), have complex motion modeling due to their complex spline curve bending shape, and their torsional resistance is poor. Some contact-assisted structures limit the bending shape of the joints, such as the invention patent "A Cam-Assisted Flexible Continuous Robot Unit and Robot" (Publication No. CN 113814966 A), which uses a cam mechanism in the middle, and the invention patent "Based on a Gear and Tooth Rolling Unit and a Snake-Shaped Arm Structure Having It" (Publication No. CN 114654455 A), which uses gear teeth for rolling connection. However, each joint in these structures has only one degree of freedom, and they are arranged at 90° intervals, further increasing the difficulty of modeling.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of the present invention, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a ball-cage type flexible variable stiffness continuum robot unit and a continuum robot. It employs a ball-cage joint design, with each joint having two degrees of freedom, making it more flexible and adaptable. Furthermore, adjacent structural units rotate around the center of the sphere, simplifying modeling. A flexible spring connection design is also used, providing the robotic arm with a certain degree of stiffness and giving it variable stiffness characteristics. Simultaneously, the ball bearing structure gives it strong torsional resistance, enabling it to withstand large torsional loads and better adapt to performing tasks in different environments.

[0006] The objective of this invention is achieved through the following technical solution. The ball-cage type flexible variable stiffness continuum robot unit includes,

[0007] Multiple main structural units are interconnected to form a robotic arm. The main structural units include...

[0008] A spherical shell structure, comprising,

[0009] An annular support surface having a central through hole.

[0010] Three outer raceways are equidistantly distributed on the outermost ring of the annular support surface and extend upward from the annular support surface. The spherical raceways of the three outer raceways all face the central axis of the annular support surface.

[0011] Multiple spring-loaded limit pins are distributed throughout the annular support surface between adjacent outer raceways.

[0012] Multiple drive line through holes are distributed throughout the annular support surface between adjacent spring limit posts.

[0013] A connecting cylinder extends downward from the central through hole of the annular support surface, and a connecting keyway is provided on the side wall of the connecting cylinder and extends in a direction parallel to the central axis.

[0014] A star-shaped nested structure, comprising,

[0015] Three inner raceways are equidistantly distributed on the outer wall of the star-shaped sleeve structure. These inner raceways cooperate with the outer raceways of adjacent main structural units to accommodate the balls.

[0016] A connecting key is arranged on the inner wall of the star-shaped sleeve structure and aligned with the inner wall of the central through hole. The connecting key connects the connecting keyway to connect the star-shaped sleeve structure and the spherical shell structure.

[0017] Multiple joint connection structures connect two adjacent main structural units. The joint connection structures include...

[0018] A triangular retainer is arranged between the spherical shell structure of one main structural unit and the star-shaped sleeve structure of the previous main structural unit.

[0019] Three balls are nested in holes at the three corners of a triangular cage. These balls are assembled in a raceway formed by the outer raceway of the spherical shell structure of one main structural unit and the inner raceway of the star-shaped sleeve structure of the previous main structural unit.

[0020] Multiple flexible springs, with their two ends connected to spring limiting posts of two adjacent spherical shell structures;

[0021] The front-end unit, located at the very tip of the robotic arm, includes:

[0022] The unit body includes a central threaded hole extending along the central axis.

[0023] Multiple side grooves are recessed inward from the side surface of the unit body in a direction perpendicular to the central axis.

[0024] Multiple drive line through holes are provided on the bottom surface of the side groove.

[0025] Multiple spring-loaded limiting posts are located at the bottom of the unit body.

[0026] A connecting cylinder extends downward from the central threaded hole of the front end unit body. A connecting keyway is provided on the side wall of the connecting cylinder body and extends in a direction parallel to the central axis. The connecting keyway connects to the connecting key of the adjacent main structural unit body.

[0027] The rear-end unit, located at the very rear of the robotic arm, includes:

[0028] An annular support surface having a central through hole.

[0029] Three outer raceways are equidistantly distributed on the outermost ring of the annular support surface and extend upward from the annular support surface. The spherical raceways of the three outer raceways all face the central axis of the annular support surface.

[0030] Multiple spring-loaded limit pins are distributed throughout the annular support surface between adjacent outer raceways.

[0031] Multiple drive line through holes are distributed throughout the annular support surface between adjacent spring limit posts.

[0032] A connecting chassis is located at the bottom of the annular support surface of the rear unit, and multiple mounting and fixing holes are distributed around the periphery of the connecting chassis.

[0033] In the aforementioned spherical cage-type flexible variable stiffness continuum robot unit, the unit body is a hollow cylindrical structure.

[0034] In the aforementioned ball cage type flexible variable stiffness continuous robot unit, the front end unit is threadedly connected to the operating instrument via a central threaded hole.

[0035] In the aforementioned ball-cage type flexible variable stiffness continuum robot unit, the operating instruments include a camera, a searchlight, a grinder, or a scalpel.

[0036] In the aforementioned ball cage type flexible variable stiffness continuous robot unit, the rear unit body is fixedly connected to the drive system via mounting holes.

[0037] In the aforementioned ball-cage type flexible variable stiffness continuum robot unit, the outer surfaces of the three corners of the triangular cage are spherical.

[0038] In the aforementioned ball cage type flexible variable stiffness continuous robot unit, the spherical shell structure is fitted outside the triangular cage with a clearance fit, and the star-shaped sleeve structure is nested inside the triangular cage with a clearance fit. The spherical shell structure, the triangular cage, and the star-shaped sleeve structure form a ball pair connection.

[0039] In the aforementioned ball cage type flexible variable stiffness continuous robot unit, the diameter of the central through hole is the same as the diameter of the central threaded hole.

[0040] In the aforementioned ball-cage type flexible variable stiffness continuous robot unit, the front-end unit, the main structural unit, and the rear-end unit are connected in series on the same bending central axis.

[0041] A continuum robot includes the aforementioned ball cage type flexible variable stiffness continuum robot unit, wherein multiple drive lines sequentially pass through drive line through holes in the front end unit, the main structural unit, and the rear end unit to form a continuum robot.

[0042] Compared with the prior art, the advantages of the present invention are:

[0043] 1. The present invention adopts a ball cage structure, in which the spherical shell structure, the triangular cage and the star-shaped sleeve structure are nested together to form a ball joint connection. Each joint has two degrees of freedom, realizing single joint universal joint, making the robotic arm more flexible and versatile.

[0044] 2. The present invention also has a definite motion trajectory. Since the joint is connected by a ball joint, the adjacent structural units rotate around the center of the ball, making the modeling more accurate and convenient.

[0045] 3. The present invention also has strong anti-torsion ability. The three balls are placed in the inner and outer raceways. When two adjacent unit structures are about to be torn, the balls and the inner and outer raceways generate contact torsional force, which restricts the torsional displacement of the inner and outer raceways, thereby greatly improving the anti-torsion ability of the entire structure and enabling it to withstand large torsional loads.

[0046] 4. The present invention also incorporates flexible joints, with springs arranged on both sides of the outer raceway at each joint. When the joint is not bending, the springs are already in a stretched state. When the joint bends, the spring stretch decreases in the bending direction, and the tension decreases, while the tension increases in the bending direction. This provides a certain rigidity to the entire robotic arm, offsetting some of the negative effects of gravity. More importantly, it enables the robotic arm to have variable stiffness characteristics. The joint stiffness varies with the bending angle of the joint, avoiding the problem of large differences in the angle of each joint in the same segment caused by underactuation, and improving control accuracy.

[0047] 5. The present invention also provides through holes in the middle of the entire structure to accommodate operating instruments, such as cables, cameras, searchlights, grinders, scalpels, etc., which can better adapt to different environments for operation.

[0048] The above description is merely an overview of the technical solution of the present invention. In order to make the technical means of the present invention clearer and more understandable, so that those skilled in the art can implement it according to the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more obvious and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0049] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0050] In the attached diagram:

[0051] Figure 1 This is a schematic diagram of the ball cage type flexible variable stiffness continuum robot unit and the continuum robot of the present invention;

[0052] Figure 2 This is a schematic diagram of the main structural unit body in this invention;

[0053] Figure 3 This is a schematic diagram of the spherical shell structure in this invention;

[0054] Figure 4 This is a schematic diagram of the star-shaped sleeve structure in this invention;

[0055] Figure 5 This is a schematic diagram of the front-end unit body in this invention;

[0056] Figure 6 This is a schematic diagram of the structure of the back-end unit in this invention;

[0057] Figure 7 This is a schematic diagram of the joint connection structure in this invention;

[0058] Figure 8 This is an exploded view of the joint connection structure in this invention;

[0059] Figure 9 This is a schematic diagram of the structure of the continuous robotic arm after deformation according to the present invention.

[0060] The present invention will be further explained below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0061] Specific embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While specific embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0062] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments for carrying out the invention; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of the invention. The scope of protection of this invention is determined by the appended claims.

[0063] To facilitate understanding of the embodiments of the present invention, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. The accompanying drawings do not constitute a limitation on the embodiments of the present invention.

[0064] To better understand, such as Figures 1 to 9 As shown, a ball cage type flexible variable stiffness continuous robot unit includes a main structural unit 1, a joint connection structure 2, a front unit 3, and a rear unit 4; several main structural units 1 are interconnected, the front unit 3 is arranged at the front end, and the rear unit is arranged at the rear end. An operating tool is arranged at the central threaded hole 31 of the front unit 3, and multiple drive lines pass through the drive line through holes 114 in sequence, forming a ball cage type flexible variable stiffness continuous robot unit and robot.

[0065] like Figure 2 As shown, the main structural unit 1 includes a spherical shell structure 11 and a star-shaped sleeve structure 12; the connection between the spherical shell structure 11 and the star-shaped sleeve structure 12 is a key connection.

[0066] like Figure 3As shown, the spherical shell structure 11 includes an outer raceway 111, spring limiting posts 112, a connecting keyway 113, and a drive line through hole 114. The outer raceway 111 is a hemispherical raceway, with three in total, arranged at 120° angles on the outermost ring of the spherical shell structure 11, and cooperates with the inner raceway 121 to accommodate the ball 23. The spring limiting posts 112 are arranged next to the outer raceway 111, with six in total, and are used to fix the flexible spring 22. The connecting keyway 113 is arranged on the side wall of the central through hole and is used to connect with the star-shaped sleeve structure 12. The drive line through hole 114 is arranged between the spring limiting posts 112 and is used to pass the drive line.

[0067] like Figure 4 As shown, the star-shaped sleeve structure 12 includes an inner raceway 121 and a connecting key 122; the inner raceway 121 is a hemispherical raceway, and there are three of them, which are arranged at a 120° angle on the side wall of the star-shaped sleeve structure 12, and cooperate with the outer raceway 111 to accommodate the ball 23; the connecting key 122 is arranged on the inner wall of the central through hole and is used to connect with the spherical shell structure 11.

[0068] like Figure 5 As shown, the front-end unit 3 includes a central threaded hole 31, a spring limiting post 112, a connecting keyway 113, and a drive line through hole 114; the central threaded hole 31 is arranged at the top center of the front-end unit 3, and the threaded hole can be connected to operating tools, such as cameras, grinders, scalpels and other equipment; the rest of the structure is the same as the spherical shell structure 11.

[0069] like Figure 6 As shown, the rear unit 4 includes a connecting chassis 41, mounting holes 42, an outer raceway 111, a spring limiting post 112, and a drive line through hole 114; the connecting chassis 41 is connected to the rear drive system through the mounting holes 42; the rest of the structure is the same as the spherical shell structure 11.

[0070] like Figure 7 As shown, the joint connection structure 2 includes a triangular retainer 21, a flexible spring 22, and ball bearings 23. The triangular retainer 21 is arranged between the spherical shell structure 11 and the star-shaped sleeve structure 12, and they are nested together with a clearance fit. The two ends of the flexible spring 22 are connected to two adjacent spherical shell structures 11. The ball bearings 23 are nested in the three holes of the triangular retainer 21 and are then installed in the raceways formed between the spherical shell structure 11 and the star-shaped sleeve structure 12.

[0071] like Figure 8As shown, the triangular retainer 21 has spherical sidewalls in three directions, with three through holes on the sidewalls to limit the movement of the ball bearing 23; the flexible spring 22 is connected to the spring limiting post 112 and connects two adjacent main structural units 1; the ball bearing 23 is placed in the raceway formed by the outer raceway 111 and the inner raceway 121; each pair of adjacent main structural units 1 are connected by a joint connection structure 2 to form a joint, in which the spherical shell structure 11 is on the outside, the star-shaped sleeve structure 12 is on the inside, and the triangular retainer 21 is between the two, with their spherical surfaces contacting and nesting each other, forming a clearance fit and a spherical pair connection.

[0072] like Figure 9 As shown, when the ball cage type flexible variable stiffness continuous robot unit works with the robot, the driving rope applies force, causing the main structural unit 1 to rotate under pressure, the joint connection structure 2 to deform, and the entire robotic arm to reach the required deformation state.

[0073] In one embodiment, a ball-cage type flexible variable stiffness continuous robot unit includes a main structural unit 1, a joint connection structure 2, a front unit 3, and a rear unit 4. Several main structural units 1 are interconnected, with the front unit 3 positioned at the foremost end and the rear unit at the rearmost end. An operating tool is positioned at the central threaded hole 31 of the front unit 3. Multiple drive lines pass sequentially through drive line through holes 114, forming the ball-cage type flexible variable stiffness continuous robot unit and the robot. When the robotic arm is working, the rear unit 4 is connected to the drive system. The drive system pulls the drive lines, causing each unit to rotate under pressure. In the joint connection structure 2, a spherical shell structure 11 is on the outside, a star-shaped sleeve structure 12 is on the inside, and a triangular retainer 21 is between them. Their spherical surfaces are in contact and nested together, forming a clearance fit and a ball-joint connection. The joints rotate around the center of the spheres to achieve the desired deformation state. Each joint has two degrees of freedom, therefore a single joint can rotate in all directions, making it flexible, adaptable, and highly responsive.

[0074] Springs are arranged on both sides of the outer raceway at each joint. When the joint is not bending, the springs are already in a stretched state. When the joint bends, the spring stretch decreases in the bending direction, and the tension decreases, while the tension increases in the bending direction. This provides a certain stiffness to the entire robotic arm, offsetting some of the negative effects of gravity. More importantly, it enables the robotic arm to have variable stiffness characteristics. The joint stiffness varies with the bending angle of the joint, avoiding the problem of large differences in the angle of each joint in the same segment caused by underactuation, and improving control accuracy.

[0075] When two adjacent structural units are about to undergo torsion, the three balls placed in the inner and outer raceways generate contact torsional force, which limits the torsional displacement of the inner and outer raceways, thereby greatly improving the torsional resistance of the entire structure and enabling it to withstand larger torsional loads.

[0076] The structure has through holes in the middle to accommodate operating instruments such as cables, cameras, spotlights, grinders, and scalpels, allowing it to better adapt to different environments for operation.

[0077] In one embodiment, the ball-cage type flexible variable stiffness continuum robot unit includes:

[0078] Main structural unit 1, which are interconnected to form a continuous robotic arm;

[0079] Joint connection structure 2 connects two adjacent main structural units 1;

[0080] Front unit 3 is located at the very front end of the robotic arm;

[0081] The rear unit 4 is located at the very rear of the robotic arm.

[0082] Further, the main structural unit 1 includes a spherical shell structure 11 and a star-shaped sleeve structure 12; the connection between the spherical shell structure 11 and the star-shaped sleeve structure 12 is a key connection. The joint connection structure 2 includes a triangular retainer 21, a flexible spring 22, and ball bearings 23; the triangular retainer 21 is arranged between the spherical shell structure 11 and the star-shaped sleeve structure 12, nested together with a clearance fit; the two ends of the flexible spring 22 are connected to two adjacent spherical shell structures 11; the ball bearings 23 are nested in the three holes of the triangular retainer 21, and then respectively installed in the raceways formed between the spherical shell structure 11 and the star-shaped sleeve structure 12. The front end unit 3 includes a central threaded hole 31, a spring limiting post 112, a connecting keyway 113, and a drive line through hole 114; the central threaded hole 31 is arranged at the top center of the front end unit 3, and the threaded hole can be connected to operating tools, such as cameras, grinders, scalpels, etc. The rear-end unit 4 includes a connecting chassis 41, mounting holes 42, an outer raceway 111, a spring limiting post 112, and a drive line through hole 114; the connecting chassis 41 is connected to the rear-end drive system through the mounting holes 42. The spherical shell structure 11 includes an outer raceway 111, a spring limiting post 112, a connecting keyway 113, and a drive line through hole 114; the outer raceway 111 is a spherical raceway, arranged on the outermost ring of the spherical shell structure 11, and cooperates with the inner raceway 121 to accommodate the ball 23; the spring limiting post 112 is arranged next to the outer raceway 111 to fix the flexible spring 22; the connecting keyway 113 is arranged on the side wall of the central through hole to connect with the star-shaped sleeve structure 12; the drive line through hole 114 is arranged between the spring limiting posts 112 to pass through the drive line. The star-shaped sleeve structure 12 includes an inner raceway 121 and a connecting key 122. The inner raceway 121 is arranged on the side wall of the star-shaped sleeve structure 12 and cooperates with the outer raceway 111 to accommodate the ball 23. The connecting key 122 is arranged on the inner wall of the central through hole and is used to connect with the spherical shell structure 11. The side walls of the triangular retainer 21 in three directions are spherical, and three through holes are opened on the side walls to limit the movement of the ball 23. The flexible spring 22 is connected to the spring limiting post 112 and connects two adjacent main structural unit bodies 1. The ball 23 is placed in the raceway formed by the outer raceway 111 and the inner raceway 121. Each pair of adjacent main structural unit bodies 1 are connected by a joint connection structure 2 to form a joint. In the joint, the spherical shell structure 11 is on the outside, the star-shaped sleeve structure 12 is on the inside, and the triangular retainer 21 is between the two. Their spherical surfaces are in contact and nested with each other, forming a clearance fit and a spherical pair connection. Several main structural units 1 are interconnected. The front unit 3 is arranged at the front end and the rear unit is arranged at the rear end. An operating tool is arranged at the central threaded hole 31 of the front unit 3. Multiple drive lines pass through the drive line through hole 114 in sequence to form a ball cage type flexible variable stiffness continuous robot.

[0083] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not restrict the application from being implemented using the specific details described above.

[0084] The above description has been provided for illustrative and descriptive purposes. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although several embodiments have been discussed above, those skilled in the art will recognize, through the teachings of this specification and without departing from the scope of the claims, various variations, modifications, additions, and sub-combinations thereof, all of which fall within the scope of protection of this invention.

Claims

1. A ball-cage type flexible variable stiffness continuum robot unit, characterized in that, It includes, Multiple main structural units are interconnected to form a robotic arm. The main structural units include... Spherical shell structure, which includes, An annular support surface having a central through hole. Three outer raceways are equidistantly distributed on the outermost ring of the annular support surface and extend upward from the annular support surface. The spherical raceways of the three outer raceways all face the central axis of the annular support surface. Multiple spring-loaded limit pins are distributed throughout the annular support surface between adjacent outer raceways. Multiple drive line through holes are distributed throughout the annular support surface between adjacent spring limit posts. A connecting cylinder extends downward from the central through hole of the annular support surface, and a connecting keyway is provided on the side wall of the connecting cylinder and extends in a direction parallel to the central axis. A star-shaped nested structure, comprising, Three inner raceways are equidistantly distributed on the outer wall of the star-shaped sleeve structure. These inner raceways cooperate with the outer raceways of adjacent main structural units to accommodate the balls. A connecting key is arranged on the inner wall of the star-shaped sleeve structure and aligned with the inner wall of the central through hole. The connecting key connects the connecting keyway to connect the star-shaped sleeve structure and the spherical shell structure. Multiple joint connection structures connect two adjacent main structural units. The joint connection structures include... A triangular retainer is arranged between the spherical shell structure of one main structural unit and the star-shaped sleeve structure of the previous main structural unit. Three balls are nested in holes at the three corners of a triangular cage. These balls are assembled in a raceway formed by the outer raceway of the spherical shell structure of one main structural unit and the inner raceway of the star-shaped sleeve structure of the previous main structural unit. Multiple flexible springs, with their two ends connected to spring limiting posts of two adjacent spherical shell structures; The front-end unit, located at the very tip of the robotic arm, includes: The unit body includes a central threaded hole extending along the central axis. Multiple side grooves are recessed inward from the side surface of the unit body in a direction perpendicular to the central axis. Multiple drive line through holes are provided on the bottom surface of the side groove. Multiple spring-loaded limiting posts are located at the bottom of the unit body. A connecting cylinder extends downward from the central threaded hole of the front end unit body. A connecting keyway is provided on the side wall of the connecting cylinder body and extends in a direction parallel to the central axis. The connecting keyway connects to the connecting key of the adjacent main structural unit body. The rear-end unit, located at the very rear of the robotic arm, includes... An annular support surface having a central through hole. Three outer raceways are equidistantly distributed on the outermost ring of the annular support surface and extend upward from the annular support surface. The spherical raceways of the three outer raceways all face the central axis of the annular support surface. Multiple spring-loaded limit pins are distributed on the annular support surface between adjacent outer raceways. Multiple drive line through holes are distributed throughout the annular support surface between adjacent spring limit posts. A connecting chassis is located at the bottom of the annular support surface of the rear unit, and multiple mounting holes are distributed around the periphery of the connecting chassis.

2. The ball-cage type flexible variable stiffness continuum robot unit as described in claim 1, characterized in that, The unit body is a hollow cylindrical structure.

3. The ball-cage type flexible variable stiffness continuum robot unit as described in claim 1, characterized in that, The front unit is threadedly connected to the operating instrument via the central threaded hole.

4. The ball-cage type flexible variable stiffness continuum robot unit as described in claim 3, characterized in that, Operating instruments include cameras, searchlights, grinders, or scalpels.

5. The ball-cage type flexible variable stiffness continuum robot unit as described in claim 1, characterized in that, The back-end unit is fixedly connected to the drive system via mounting holes.

6. The ball-cage type flexible variable stiffness continuum robot unit as described in claim 1, characterized in that, The outer surfaces of the three corners of the triangular cage are spherical.

7. The ball-cage type flexible variable stiffness continuum robot unit as described in claim 1, characterized in that, The diameter of the center through hole is the same as the diameter of the center threaded hole.

8. A continuum robot, characterized in that, It includes a ball cage type flexible variable stiffness continuous robot unit as described in any one of claims 1-7, wherein multiple drive lines pass through the drive line through holes of the front unit body, the main structural unit body and the rear unit body in sequence to form a continuous robot.

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