Composite super-redundant mechanical arm with ultrahigh length-diameter ratio and high load

Abstract

The invention discloses an ultrahigh-length-diameter-ratio and high-load composite super-redundant mechanical arm, which relates to the technical field of super-redundant mechanical arms and comprises a telescopic arm assembly, a flexible arm assembly and a power transmission structure, the telescopic arm assembly is composed of a transmission shaft, an arm body fixing disc, a transmission lead screw, a lead screw nut, a transmission sliding block, a telescopic arm outer arm cylinder, a telescopic arm inner arm cylinder and a linear rolling bearing. According to the invention, high-rigidity telescopic transmission of the telescopic arm assembly and asymmetric variable joint design of the flexible arm are deeply fused, and a rigid connection structure of an inner arm cylinder of the telescopic arm with main bearing force and a switching rope guide disc is supplemented, so that the problem of structural instability under an ultrahigh length-diameter ratio is cooperatively solved; and when the high load capacity is guaranteed, super-redundant multi-degree-of-freedom movement is achieved, and the large-range precise operation capacity of the mechanical arm in the narrow unstructured environment is remarkably expanded.

Description

Technical Field

[0001] This invention relates to the field of super-redundant robotic arm technology, specifically to a composite super-redundant robotic arm with ultra-high aspect ratio and high load capacity. Background Technology

[0002] A super-redundant robotic arm is a robotic arm system whose number of joint degrees of freedom significantly exceeds the minimum degrees of freedom required to complete a specific task. Redundant degrees of freedom allow the robotic arm to optimize its own configuration by adjusting the joint angles while keeping the end effector posture unchanged, thereby achieving obstacle avoidance, energy saving or extending service life.

[0003] The drawbacks of existing super-redundant robotic arms are:

[0004] 1. Patent document US20110137464A1 discloses a robotic arm for controlling the movement of a human arm. However, the robotic arm in the above document is prone to structural instability under ultra-high length-to-diameter ratio, resulting in low load capacity and insufficient degree of automation and motion redundancy.

[0005] 2. Patent document JP2017042868A discloses a method for controlling redundant robotic arms, but the robotic arms in the above document lack the technical problems of multi-source collaborative sensing and real-time data fusion processing.

[0006] 3. Patent document JP2015529163A discloses the constraints of a robotic arm with redundant degrees of freedom. However, the robotic arm in the above document has technical problems such as difficulty in independently controlling the pitch and yaw motions of the joints and low precision.

[0007] 4. Patent document CN114905498A discloses a variable joint super-redundant robot arm. However, the robot arm in the above document has technical problems such as small extended stroke and low length-to-diameter ratio, making it difficult to perform operations in extreme space-constrained scenarios. Summary of the Invention

[0008] The purpose of this invention is to provide a composite super-redundant robotic arm with ultra-high length-to-diameter ratio and high load capacity to solve the technical problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a composite super-redundant robotic arm with ultra-high length-to-diameter ratio and high load capacity, comprising a telescopic arm assembly, a flexible arm assembly, and a power transmission structure, wherein the telescopic arm assembly is composed of a drive shaft, an arm body fixing plate, a drive screw, a screw nut, a drive slider, an outer telescopic arm cylinder, an inner telescopic arm cylinder, and a linear rolling bearing;

[0010] The flexible boom assembly consists of 7 boom tube units connected by universal joints. Each joint includes an active guide rope disc, a driven guide rope disc, an octahedral connector, and a pin. It also adopts an asymmetrical variable joint length design, with the length of the four first boom tubes closest to the telescopic boom assembly being greater than that of the three second boom tubes at the end.

[0011] The power transmission structure includes a boom body adapter disposed at one end of the boom cylinder inside the telescopic boom, and a transfer rope reel is provided at one end of the boom body adapter.

[0012] The arm body fixing plate simultaneously fastens the telescopic arm's outer arm cylinder and outer wall structural components;

[0013] The drive shaft is directly connected to the lead screw;

[0014] The lead screw nut is fixed to the transmission slider. The outer wall of the transmission slider is provided with three evenly distributed protrusions, and the three evenly distributed protrusions are respectively embedded in three evenly distributed grooves on the inner side of the outer arm cylinder of the telescopic arm. The transmission slider is fastened to the inner arm cylinder of the telescopic arm.

[0015] The linear rolling bearing is located between the end of the transmission screw and the inner barrel of the telescopic arm;

[0016] The internal boom cylinder of the telescopic boom serves as the main load-bearing beam, and is rigidly connected to the transfer guide rope disc at the root of the flexible boom through the boom body adapter, forming an overall rigid support structure at the root of the boom body.

[0017] Preferably, it also includes an integrated sensor system, which comprises:

[0018] A displacement sensor is installed on the transmission slider;

[0019] Miniature angle sensors are fitted into the pins of each octahedral connector;

[0020] A tension sensor is installed at the wire rope outlet of the active guide rope reel.

[0021] The data from the displacement sensor, angle sensor, and tension sensor are integrated into the microprocessor within the arm adapter via a flexible circuit.

[0022] Preferably, the transmission relationship of the telescopic arm assembly is as follows: the transmission shaft drives the transmission screw to rotate, which in turn drives the screw nut and the transmission slider to move axially along the outer arm cylinder of the telescopic arm, thereby driving the inner arm cylinder of the telescopic arm to perform linear telescopic motion. The boss of the transmission slider cooperates with the groove on the inner side of the outer arm cylinder of the telescopic arm to suppress radial sway during the telescopic process, and the linear rolling bearing provides radial support.

[0023] Preferably, the universal joint of the flexible arm assembly is as follows: adjacent joints are rotated in all directions through an active guide rope disc and a driven guide rope disc via an octahedral connector and a pin. Each universal joint is driven by three independently controlled steel wire ropes. Each joint has three sets of rope holes on its guide rope disc. The rope holes are evenly distributed at 120° around the guide rope disc and are arranged axially staggered. The pitch and yaw motion of the joints are controlled by independently retracting and extending the steel wire ropes.

[0024] Preferably, the asymmetric variable joint length design is as follows: the length of the first arm barrel is 1.8 times the length of the second arm barrel.

[0025] Preferably, the dimensional performance parameters of the robotic arm are as follows: total length of 2.8m in the retracted state, total length of 4m in the extended state, maximum outer diameter of 74mm, and end-effector load of 2kg.

[0026] Preferably, the working logic of the integrated sensing system is as follows: the displacement sensor provides feedback on the real-time position of the boom cylinder inside the telescopic arm, and after comparing it with the target stroke, the transmission shaft speed is controlled in a closed loop; the angle sensor monitors the actual deflection angle of each joint and dynamically compensates for the error in the wire rope winding and unwinding length; the tension sensor detects the load change of the wire rope, and triggers overload protection when the tension of a single wire rope exceeds the threshold.

[0027] Preferably, the working steps of this ultra-high aspect ratio, high-load composite super-redundant robotic arm are as follows:

[0028] S1. Telescopic boom deployment: The drive shaft drives the drive screw to rotate synchronously. The rotating drive screw drives the screw nut and the drive slider to move axially. Three evenly distributed protrusions on the outer wall of the drive slider are embedded in three evenly distributed grooves on the inner side of the outer boom cylinder of the telescopic boom, which constrains the drive slider to move only axially and suppresses radial sway. The drive slider is fastened to the inner boom cylinder of the telescopic boom, thereby driving the inner boom cylinder of the telescopic boom to extend outward in a straight line relative to the outer boom cylinder. The linear rolling bearing at the end of the drive screw provides radial support for the inner boom cylinder of the telescopic boom. The displacement sensor monitors the position of the drive slider and the inner boom cylinder of the telescopic boom in real time and feeds it back to the control system for closed-loop position control to ensure that the target stroke is achieved.

[0029] S2. Flexible Arm Posture Adjustment: Based on task requirements, the target deflection angle required for each universal joint is obtained. The microprocessor independently controls the extension and retraction length of the three steel wire ropes driving each joint. The extension and retraction of the steel wire ropes act on the active guide rope disc and the driven guide rope disc. The tension of the steel wire ropes is transmitted through the guide rope discs, causing adjacent boom units to pitch or yaw around the universal joint formed by the octahedral connector and pins. Angle sensors are built into the pins to monitor the actual deflection angle of each joint in real time and feed it back to the microprocessor. The microprocessor dynamically compensates for the error in the extension and retraction length of the steel wire ropes based on the angle feedback signal, realizing precise closed-loop control of the joint angle. The first boom section, which is closer to the telescopic boom, is longer, providing greater load-bearing capacity and range of motion. The second boom section, which is shorter at the end, provides higher flexibility and end-positioning accuracy.

[0030] S3. End-effector and load support: The task load is installed on the end-effector of the flexible arm. The force and torque generated by the load are transmitted through the arm cylinder unit and universal joint of the flexible arm. The transfer guide rope disc at the root of the flexible arm is rigidly connected to the internal arm cylinder of the telescopic arm through the arm body adapter. The internal arm cylinder of the telescopic arm serves as the main load-bearing beam of the entire robotic arm, bearing the main bending moment and axial force from the flexible arm and the end-effector load. It is transmitted to the external base structure through the arm body fixing disc, forming a stable overall rigid support structure at the root of the arm body. The tension sensor monitors the tension of the drive wire rope of each joint in real time. When the tension of a single wire rope exceeds the preset safety threshold, the control system immediately triggers the overload protection mechanism to prevent damage to the universal joint or drive components.

[0031] S4. Motion Coordination and Status Monitoring: According to the task requirements, coordinate the linear telescopic motion of the telescopic arm and the multi-joint bending motion of the flexible arm to achieve the super-redundant motion capability of the entire robotic arm in confined spaces or complex environments. All sensor data are aggregated through flexible circuits to the microprocessor in the arm body adapter for preliminary processing and packaging.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] 1. This invention deeply integrates the high rigidity telescopic transmission of the telescopic arm assembly with the asymmetric variable joint design of the flexible arm, and is supplemented by the rigid connection structure between the internal arm cylinder of the telescopic arm and the transfer guide rope disc, which solves the problem of structural instability under ultra-high length-to-diameter ratio. While ensuring high load capacity, it achieves ultra-redundant multi-degree-of-freedom motion, which significantly expands the robotic arm's ability to perform large-scale precise operations in narrow and unstructured environments.

[0034] 2. This invention utilizes an integrated sensor system to collaboratively sense displacement, angle, and tension, combined with multi-source data fusion processing by the microprocessor within the arm adapter, to construct a complete intelligent closed loop from mechanical structure status monitoring to motion control. While ensuring safety during high-load operations, it significantly improves the positioning accuracy and dynamic response speed of the ultra-long flexible arm in multi-degree-of-freedom motion, greatly enhancing the adaptability of the robotic arm under complex working conditions.

[0035] 3. This invention utilizes a flexible boom assembly with three steel wire ropes driven by staggered holes and an octahedral universal joint. The axially staggered 120° evenly distributed rope holes eliminate steel wire rope interference, enabling independent and precise control of joint pitch and yaw movements. Combined with a 1.8 times asymmetric boom design, it can ensure the super-redundant motion capability of the seven-section universal joint while improving the bending stiffness of the base section and the end response speed, ultimately achieving the effect of high load and ultra-large workspace.

[0036] 4. With its dynamic deformation capability of an extreme folding length of 2.8m and an extended stroke of 4m, and a 74mm ultra-thin body capable of carrying a 2kg load, this invention allows the robotic arm to be folded up and pass through holes with a diameter of 80mm in extreme space-constrained scenarios such as nuclear power pipeline maintenance and spacecraft cabin operations. It can also be deployed to perform large-scale precision operations. It has an extremely high length-to-diameter ratio, breaks through traditional limitations, and improves the adaptability of the maximum achievable distance and effective path for deep cavity detection. Attached Figure Description

[0037] Figure 1 This is a three-dimensional schematic diagram of the overall structure of the present invention;

[0038] Figure 2 This is a schematic diagram of the overall side structure of the present invention;

[0039] Figure 3 This is a schematic diagram of the telescopic arm assembly structure of the present invention;

[0040] Figure 4 This is a cross-sectional view of the telescopic arm assembly of the present invention;

[0041] Figure 5 This is a schematic diagram of the flexible arm assembly structure of the present invention;

[0042] Figure 6 This is a schematic diagram of the universal joint structure of the present invention;

[0043] Figure 7 This is a schematic diagram of the microprocessor flow of the present invention;

[0044] Figure 8 This is a schematic diagram of the workflow of the present invention.

[0045] In the diagram: 3. Drive shaft; 4. Boom body fixing plate; 5. Drive screw; 6. Screw nut; 7. Drive slider; 8. External boom cylinder of telescopic boom; 9. Internal boom cylinder of telescopic boom; 10. Linear rolling bearing; 11. Universal joint; 12. Active rope guide disc; 13. Driven rope guide disc; 14. Octahedral connector; 15. Pin; 16. First boom cylinder; 17. Second boom cylinder; 18. Boom body adapter; 19. Adapter rope guide disc; 20. Displacement sensor; 21. Angle sensor; 22. Tension sensor; 23. Microprocessor. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0048] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0049] Example 1: Please refer to Figure 1 , Figure 2 , Figure 3 and Figure 4This invention provides an embodiment of a high aspect ratio, high load-bearing composite super-redundant robotic arm, comprising a telescopic arm assembly, a flexible arm assembly, and a power transmission structure. The telescopic arm assembly consists of a drive shaft 3, an arm body fixing plate 4, a drive screw 5, a screw nut 6, a drive slider 7, an outer telescopic arm cylinder 8, an inner telescopic arm cylinder 9, and a linear rolling bearing 10. The flexible arm assembly consists of arm cylinder units connected by seven universal joints 11. Each joint includes an active guide rope disc 12, a driven guide rope disc 13, an octahedral connector 14, and a pin 15, and adopts an asymmetric variable joint length design. The length of the four first arm cylinder sections 16 closest to the telescopic arm assembly is greater than that of the three last second arm cylinder sections 17. The power transmission structure includes an inner arm cylinder located within the telescopic arm assembly. The boom adapter 18 is located at one end of the boom 9. A transfer guide 19 is provided at one end of the boom adapter 18. The boom fixing plate 4 is fastened to the outer boom cylinder 8 and the outer wall structure of the telescopic boom. The drive shaft 3 is directly connected to the drive screw 5. The screw nut 6 is fixed on the drive slider 7. The outer wall of the drive slider 7 is provided with three evenly distributed bosses. The three evenly distributed bosses are respectively embedded in three evenly distributed grooves on the inner side of the outer boom cylinder 8 of the telescopic boom. The drive slider 7 is fastened to the inner boom cylinder 9 of the telescopic boom. The linear rolling bearing 10 is located between the end of the drive screw 5 and the inner boom cylinder 9 of the telescopic boom. The inner boom cylinder 9 of the telescopic boom serves as the main load-bearing beam. It is rigidly connected to the transfer guide 19 at the root of the flexible boom through the boom adapter 18, forming an overall rigid support structure at the root of the boom.

[0050] Furthermore, the ultra-high aspect ratio and high load capacity are achieved in synergy: the telescopic arm assembly provides rigid support and powerful telescopic drive, and the flexible arm assembly enables flexible movement with multiple degrees of freedom, breaking through the aspect ratio limit of traditional robotic arms while ensuring the end-effector load capacity.

[0051] Motion performance optimization: The flexible boom adopts an asymmetrical design, with four long boom sections at the near end and three short boom sections at the far end. This not only enhances the bending stiffness of the base section to transmit large loads, but also improves the motion accuracy and flexibility of the far end, making it suitable for operation in complex and confined spaces.

[0052] Efficient power transmission and structural stability: The internal transmission shaft 3 and transmission screw 5 of the telescopic arm assembly, together with the linear rolling bearing 10 and transmission slider 7, ensure high precision, low friction and torsion resistance of the telescopic movement;

[0053] The internal boom cylinder 9 of the telescopic boom serves as the main load-bearing beam. It is rigidly connected to the flexible boom transfer guide rope disc 19 via the boom body adapter 18, forming an integral root support, which greatly improves the system's bending stiffness and power transmission efficiency.

[0054] Expansion of super-redundant degrees of freedom: 7 universal joints with 11 guide rope discs enable super-redundant motion capabilities similar to a biological spine, and the workspace coverage is further expanded by combining the telescopic stroke.

[0055] Example 2: Please refer to Figure 2 , Figure 4 , Figure 6 and Figure 7 One embodiment of the present invention further includes an integrated sensor system, comprising: a displacement sensor 20 disposed on the transmission slider 7; a miniature angle sensor 21 fitted into the pins 15 of each octahedral connector 14; and a tension sensor 22 disposed at the wire rope outlet of the active guide rope disc 12. The data from the displacement sensor 20, angle sensor 21, and tension sensor 22 are integrated into a microprocessor 23 within the arm body adapter 18 via a flexible circuit. The working logic of the integrated sensor system is as follows: the displacement sensor 20 provides feedback on the real-time position of the boom cylinder 9 inside the telescopic arm, and after comparing it with the target stroke, it controls the rotational speed of the transmission shaft 3 in a closed loop; the angle sensor 21 monitors the actual deflection angle of each joint and dynamically compensates for the wire rope length error; and the tension sensor 22 detects changes in the wire rope load, triggering overload protection when the tension of a single wire rope exceeds a threshold.

[0056] Furthermore, precise control of telescopic motion: the displacement sensor 20 on the transmission slider 7 monitors the position of the internal boom cylinder 9 of the telescopic arm in real time, and after dynamic comparison with the target stroke, the speed of the transmission shaft 3 is adjusted in a closed loop to ensure telescopic accuracy;

[0057] Joint motion error compensation: The miniature angle sensor 21 embedded in the octahedral connector 14 and pin 15 directly captures the actual deflection angle of each joint, dynamically corrects the deviation of the wire rope winding and unwinding length, and thus improves the positioning accuracy of the flexible arm end.

[0058] Active safety protection: The tension sensor 22 at the active guide rope disc 12 detects the load of the wire rope in real time. When the tension of a single rope exceeds the threshold, the overload protection is triggered instantaneously to avoid damage to the universal joint 11.

[0059] System integration advantages: All sensor data is aggregated through flexible circuits to the microprocessor 23 inside the arm adapter 18, realizing the integration of sensing, control and execution, and providing millisecond-level dynamic response capability for ultra-redundant motion.

[0060] Example 3: Please refer to Figure 1 and Figure 4 In one embodiment of the present invention, the transmission relationship of the telescopic arm assembly is as follows: the transmission shaft 3 drives the transmission screw 5 to rotate, which drives the screw nut 6 and the transmission slider 7 to move axially along the outer arm cylinder 8 of the telescopic arm, thereby driving the inner arm cylinder 9 of the telescopic arm to perform linear telescopic movement. The boss of the transmission slider 7 cooperates with the groove on the inner side of the outer arm cylinder 8 of the telescopic arm to suppress radial sway during the telescopic process. The linear rolling bearing 10 provides radial support.

[0061] Furthermore, through efficient power transmission: the drive shaft 3 directly drives the drive screw 5 to rotate, and the rotational motion is converted into the axial translation of the drive slider 7 through the screw nut 6, making the power transmission path simple and efficient;

[0062] Motion accuracy assurance: The three protrusions of the transmission slider 7 are tightly fitted with the inner groove of the outer arm cylinder 8 of the telescopic arm, which suppresses radial sway throughout the telescopic process and ensures the accuracy of the linear motion trajectory of the inner arm cylinder 9 of the telescopic arm.

[0063] Low-resistance and high-stability support: The linear rolling bearing 10 provides radial support to the end of the transmission screw 5, which significantly reduces frictional resistance and avoids vibration and deformation caused by the weight of the transmission screw 5.

[0064] Balance between rigidity and lightweight: The inner boom cylinder 9 of the telescopic boom acts as the main load-bearing beam to directly drive the telescopic movement, while the outer boom cylinder 8 guides and constrains the transmission slider 7 through the groove. The dual structure works together to achieve high rigidity telescopic movement and lightweight design.

[0065] Example 4: Please refer to Figure 1 , Figure 2 , Figure 5 and Figure 6 In one embodiment of the present invention, the universal joint 11 of the flexible arm assembly is: adjacent joints are connected by an active guide rope disc 12 and a driven guide rope disc 13 via an octahedral connector 14 and a pin 15 to achieve universal rotation. Each universal joint 11 is driven by three independently controlled steel wire ropes. Each joint has three sets of rope holes on its guide rope disc. The rope holes are evenly distributed at 120° around the guide rope disc and are arranged axially staggered. The pitch and yaw motion of the joints are controlled by independently retracting and extending the steel wire ropes. The asymmetric variable joint length design is as follows: the length of the first arm cylinder 16 is 1.8 times the length of the second arm cylinder 17.

[0066] Furthermore, multi-degree-of-freedom precision drive: each joint is controlled by three independent steel wire ropes evenly distributed in a 120° circumferential direction. Combined with the axially staggered arrangement design of the guide rope coil holes, it effectively eliminates interference between ropes and achieves precise decoupling control of pitch and yaw motion.

[0067] High flexibility support for universal joint: The active guide rope disc 12 and the driven guide rope disc 13 form a ball joint-like structure through the octahedral connector 14 and the pin 15, which can achieve large-angle deflection while ensuring the bending stiffness of the joint.

[0068] Asymmetric structural mechanics optimization: The length of the first arm tube 16 of the four sections at the near end is 1.8 times the length of the second arm tube 17 of the three sections at the far end, which greatly improves the bending stiffness of the base section to transmit the high load of the telescopic arm, while shortening the end lever arm significantly reduces the moment of inertia.

[0069] Example 5: Please refer to Figure 1The present invention provides an embodiment of the following: the dimensional performance parameters of the robotic arm are as follows: the total length in the retracted state is 2.8m, the total length in the extended state is 4m, the maximum outer diameter is 74mm, and the end-effector load is 2kg;

[0070] Furthermore, its spatial adaptability has been greatly enhanced: with an ultra-large travel ratio of 2.8m when retracted and up to 4m when extended, combined with a 74mm ultimate outer diameter, it can pass through narrow passages and carry out large-scale operations in confined spaces.

[0071] Breakthrough in high load and lightweight design: Achieving a 2kg end load under ultra-low diameter length-to-diameter ratio conditions verifies the mechanical advantages of the asymmetric universal joint 11 and the main load-bearing beam design.

[0072] System integration boundaries expanded: The slim 74mm body can be integrated into mobile robot platforms or fixed equipment cavities, providing unprecedented super-redundant operational capabilities for special operation equipment.

[0073] Example 6: Please refer to Figure 8 The present invention provides an embodiment of the following working steps for the ultra-high aspect ratio, high load-bearing composite super-redundant robotic arm:

[0074] S1. Telescopic boom deployment: The drive shaft 3 drives the drive screw 5 to rotate synchronously. The rotating drive screw 5 drives the screw nut 6 and the drive slider 7 to move axially. The three evenly distributed protrusions on the outer wall of the drive slider 7 are embedded in the three evenly distributed grooves on the inner side of the outer boom cylinder 8 of the telescopic boom, which constrains the drive slider 7 to move only axially and suppresses radial sway. The drive slider 7 is fastened to the inner boom cylinder 9 of the telescopic boom, thereby driving the inner boom cylinder 9 of the telescopic boom to extend outward in a straight line relative to the outer boom cylinder. The linear rolling bearing 10 provides radial support for the inner boom cylinder 9 of the telescopic boom at the end of the drive screw 5. The displacement sensor 20 monitors the position of the drive slider 7 and the inner boom cylinder 9 of the telescopic boom in real time and feeds it back to the control system for closed-loop position control to ensure that the target stroke is achieved.

[0075] S2. Flexible Arm Posture Adjustment: Based on task requirements, the target deflection angle required for each universal joint 11 is obtained. The microprocessor 23 independently controls the extension and retraction length of the three steel wire ropes driving each joint. The extension and retraction of the steel wire ropes act on the active guide rope disc 12 and the driven guide rope disc 13. The tension of the steel wire ropes is transmitted through the guide rope discs, causing adjacent boom units to pitch or yaw around the universal joint formed by the octahedral connector 14 and the pin 15. The angle sensor 21 is built into the pin 15 to monitor the actual deflection angle of each joint in real time and feed it back to the microprocessor 23. The microprocessor 23 dynamically compensates for the error in the extension and retraction length of the steel wire ropes based on the angle feedback signal, realizing precise closed-loop control of the joint angle. The first boom section 16, which is closer to the telescopic boom, is longer, providing greater load-bearing capacity and range of motion. The second boom section 17, which is shorter at the end, provides higher flexibility and end-positioning accuracy.

[0076] S3. End-effector execution and load support: The task load is installed on the end cylinder of the flexible arm. The force and torque generated by the load are transmitted through the cylinder unit and universal joint 11 of the flexible arm. The transfer guide 19 at the root of the flexible arm is rigidly connected to the inner cylinder 9 of the telescopic arm through the arm body adapter 18. The inner cylinder 9 of the telescopic arm serves as the main load-bearing beam of the entire robotic arm, bearing the main bending moment and axial force from the flexible arm and the end load. It is transmitted to the external base structure through the arm body fixing plate 4, forming a stable overall rigid support structure at the root of the arm body. The tension sensor 22 monitors the tension of the drive wire rope of each joint in real time. When the tension of a single wire rope exceeds the preset safety threshold, the control system immediately triggers the overload protection mechanism to prevent damage to the universal joint 11 or drive components.

[0077] S4. Motion Coordination and Status Monitoring: According to the task requirements, coordinate the linear telescopic motion of the telescopic arm and the multi-joint bending motion of the flexible arm to realize the super-redundant motion capability of the entire robotic arm in a confined space or complex environment. All sensor data are collected by the flexible circuit and sent to the microprocessor 23 in the arm body adapter 18 for preliminary processing and packaging.

[0078] The working principle involves the deep integration of the high-rigidity telescopic transmission of the telescopic arm assembly with the asymmetric variable joint design of the flexible arm. This, coupled with the rigid connection structure between the main load-bearing beam arm cylinder and the transfer guide cable reel 19, collaboratively solves the structural instability problem under ultra-high length-to-diameter ratios. While ensuring high load capacity, it achieves ultra-redundant multi-degree-of-freedom motion, significantly expanding the robotic arm's ability to perform precise operations over a wide range in narrow, unstructured environments. Through an integrated sensor system that coordinates displacement, angle, and tension sensing, combined with multi-source data fusion processing by the microprocessor 23 within the arm body adapter 18, a complete intelligent closed loop from mechanical structure status monitoring to motion control is constructed. This ensures safety during high-load operations while significantly improving the positioning accuracy and dynamic response speed of the ultra-long flexible arm in multi-degree-of-freedom motion, greatly enhancing the robotic arm's adaptability in complex working conditions. The robotic arm assembly employs a three-wire cable staggered hole drive and an octahedral universal joint design. The axially staggered 120° evenly distributed cable holes eliminate wire cable interference, enabling independent and precise control of joint pitch and yaw movements. Combined with a 1.8x asymmetric boom design, it can ensure the super-redundant motion capability of the seven-section universal joint while improving the bending stiffness of the base section and the end-effector response speed, ultimately achieving high load capacity and ultra-large workspace. With its extreme folding length of 2.8m and dynamic deformation capability of 4m extended stroke, and a 74mm ultra-thin body capable of carrying a 2kg load, this robotic arm can both curl up to pass through 80mm diameter holes and unfold to perform large-scale precision operations in extreme space-constrained scenarios such as nuclear power pipeline maintenance and spacecraft cabin operations. It has an ultra-high length-to-diameter ratio requirement, breaking through traditional limitations and improving the adaptability of the maximum reachable distance and effective path for deep cavity exploration.

[0079] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A composite super-redundant robotic arm with ultra-high aspect ratio and high load capacity, comprising a telescopic arm assembly, a flexible arm assembly, and a power transmission structure, characterized in that: The telescopic boom assembly consists of a drive shaft (3), a boom body fixing plate (4), a drive screw (5), a screw nut (6), a drive slider (7), an outer boom cylinder (8), an inner boom cylinder (9), and a linear rolling bearing (10). The flexible arm assembly consists of a boom tube unit connected by 7 universal joints (11). Each joint includes an active guide rope disc (12), a driven guide rope disc (13), an octahedral connector (14), and a pin (15). It adopts an asymmetrical variable joint length design, with the length of the four first boom tubes (16) closer to the telescopic arm assembly being greater than that of the three second boom tubes (17) at the end. The power transmission structure includes a boom body adapter (18) disposed at one end of the boom cylinder (9) inside the telescopic boom, and a transfer guide rope disc (19) is provided at one end of the boom body adapter (18). The arm body fixing plate (4) simultaneously fastens the telescopic arm's outer arm cylinder (8) and the outer wall structure; The drive shaft (3) is directly connected to the drive screw (5); The lead screw nut (6) is fixed on the transmission slider (7). The outer wall of the transmission slider (7) is provided with three evenly distributed protrusions, and the three evenly distributed protrusions are respectively embedded in the three evenly distributed grooves on the inner side of the telescopic arm outer cylinder (8). The transmission slider (7) is tightly connected to the telescopic arm inner cylinder (9). The linear rolling bearing (10) is located between the end of the transmission screw (5) and the inner barrel (9) of the telescopic arm; The inner boom cylinder (9) of the telescopic boom serves as the main load-bearing beam. It is rigidly connected to the transfer guide rope disc (19) at the root of the flexible boom through the boom body adapter (18), forming an overall rigid support structure at the root of the boom body.

2. The composite super-redundant robotic arm with ultra-high aspect ratio and high load capacity according to claim 1, characterized in that: It also includes integrated sensor systems, which include: The displacement sensor (20) is installed on the transmission slider (7). A miniature angle sensor (21) is fitted into the pin (15) of each octahedral connector (14); Tension sensor (22) is installed at the wire rope outlet of the active guide rope disc (12); The data from the displacement sensor (20), angle sensor (21), and tension sensor (22) are integrated into the microprocessor (23) within the arm adapter (18) via a flexible circuit.

3. The composite super-redundant robotic arm with ultra-high aspect ratio and high load capacity according to claim 1, characterized in that: The transmission relationship of the telescopic arm assembly is as follows: the transmission shaft (3) drives the transmission screw (5) to rotate, which drives the screw nut (6) and the transmission slider (7) to move axially along the outer arm cylinder (8) of the telescopic arm, thereby driving the inner arm cylinder (9) of the telescopic arm to perform linear telescopic motion. The boss of the transmission slider (7) cooperates with the groove on the inner side of the outer arm cylinder (8) of the telescopic arm to suppress radial sway during the telescopic process. The linear rolling bearing (10) provides radial support.

4. The composite super-redundant robotic arm with ultra-high aspect ratio and high load capacity according to claim 1, characterized in that: The universal joint of the flexible arm assembly is as follows: adjacent joints are connected by an active guide rope disc (12) and a driven guide rope disc (13) via an octahedral connector (14) and a pin (15) to achieve universal rotation. Each universal joint is driven by three independently controlled wire ropes. Each joint has three sets of rope holes on its guide rope disc. The rope holes are evenly distributed at 120° around the guide rope disc and are arranged in an axially staggered manner. The pitch and yaw motion of the joints are controlled by independently winding and unwinding the wire ropes.

5. The composite super-redundant robotic arm with ultra-high aspect ratio and high load capacity according to claim 1, characterized in that: The asymmetric variable joint length design is as follows: the length of the first arm tube (16) is 1.8 times the length of the second arm tube (17).

6. The composite super-redundant robotic arm with ultra-high aspect ratio and high load capacity according to claim 1, characterized in that: The dimensional performance parameters of the robotic arm are as follows: total length of 2.8m in the retracted state, total length of 4m in the extended state, maximum outer diameter of 74mm, and end-effector load of 2kg.

7. A composite super-redundant robotic arm with ultra-high aspect ratio and high load capacity according to claim 2, characterized in that: The working logic of the integrated sensing system is as follows: The displacement sensor (20) provides feedback on the real-time position of the boom cylinder (9) inside the telescopic boom, and controls the rotation speed of the drive shaft (3) in a closed loop after comparing it with the target stroke; The angle sensor (21) monitors the actual deflection angle of each joint and dynamically compensates for the error in the length of the wire rope; The tension sensor (22) detects the change in the load of the wire rope, and triggers overload protection when the tension of a single wire rope exceeds the threshold.

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