Mechanical arm device and cooperative control method thereof

Abstract

This invention provides a robotic arm device, comprising multiple connected arm units and a drive assembly, which can be supplemented with a cable-stayed auxiliary drive system and an auxiliary mounting base. The main body of the robotic arm is composed of multiple connected arm units. Each arm unit consists of a rigid load-bearing frame formed by multiple parallel trusses and an end-connector assembly. The rigid load-bearing frame is formed by multiple parallel rigid members enclosed by the end-connector assembly. The cross-section of the rigid load-bearing frame is a closed-loop profile containing at least one triangle, and it is a fully open, hollow structure. Its entire load-bearing structure is formed solely by the rigid members and the end-connector assembly, without additional enclosed wall panels or internal load-bearing supports. While achieving lightweight design, the inherent rigidity of the triangular structure ensures torsional and bending resistance. The device of this invention has excellent anti-interference performance, strong operational stability, and can adapt to the non-standardized operation scenarios of traditional old orchards in my country. It has a wide range of applications and strong scalability.

Description

Technical Field

[0001] This invention relates to the field of robotic arm technology, specifically to a robotic arm device and its collaborative control method. The robotic arm device features lightweight, high rigidity, and a long reach, making it suitable for the mechanized harvesting needs of non-standardized traditional orchards. It can also be extended to a wide range of applications, from light to heavy loads, including industrial handling, underwater operations, and aerospace. Background Technology

[0002] Traditional orchards in my country mostly employ non-standardized planting methods, with tree height typically controlled below 2.5 meters and canopy radius of 2-3 meters. To achieve full canopy coverage for harvesting, robotic arms with an effective operating radius of 4 meters or even longer are required. Currently, these orchards generally face labor shortages and high manual harvesting costs, creating an urgent need for low-cost, lightweight mechanized harvesting equipment that can be mounted on small agricultural platforms.

[0003] Existing robotic arm solutions cannot meet the requirements of the above scenarios. The core bottleneck lies in the inability to resolve the synergistic contradiction between long reach (4 meters and above) and lightweight, high rigidity, and maneuverable joints. The specific shortcomings are as follows:

[0004] 1. Traditional industrial multi-joint tandem robotic arms employ a heavy-duty design with a single thick-walled tube. Increased arm span leads to an exponential increase in arm weight and joint torque, a phenomenon known in the industry as "torque explosion." With a 4-meter arm span, such robotic arms are excessively heavy, requiring high-torque drive motors. They cannot be mounted on small agricultural platforms, and their flattened posture makes them prone to tipping over. They can only be adapted to tracked heavy-duty chassis by shortening the arm span, failing to meet the portable operation needs of traditional orchards.

[0005] 2. The frame-type robotic arm with "vertical beam + horizontal beam" can achieve a certain long reach operation, but the whole is a rigid fixed structure. The frame outline is large and the flexibility of the robotic arm posture adjustment is poor. It cannot adapt to the non-standardized operation environment of traditional orchards with irregular row spacing, undulating terrain and random fruit growth. In addition, its weight is also too large and it is not portable.

[0006] In summary, none of the existing technologies are specifically designed for the characteristics of traditional old orchards in my country, nor for the core needs of long reach (4 meters or more), lightweight, drivability, and portability. There are significant technological gaps, and the core contradiction between the "torque explosion" of joint motors with long reach and the need for lightweight and high rigidity cannot be resolved. Summary of the Invention

[0007] In view of the shortcomings in the above-mentioned background technology, the present invention provides a high-rigidity long-reach robotic arm device and its collaborative control method, which can be adapted to the mechanized harvesting needs of non-standardized traditional orchards, and can also be extended to industrial handling, underwater operations, aerospace and other full range of operating conditions from light load to heavy load.

[0008] It is important to clarify that the terms "heavy load" and "light load" used in this invention are customized distinctions for harvesting scenarios, not industry-wide standards. They are defined as follows: "Heavy load" specifically refers to the design concept of traditional industrial robotic arms, which enhances rigidity through a single-tube, thick-walled structure and relies on a large-size motor to output driving torque, ultimately resulting in a heavy arm. In contrast, "light load" is the design concept proposed in this invention for orchard scenarios. Its core is a truss structure using multiple rods and thin-walled tubular components. High rigidity is achieved through structural optimization rather than material thickening, coupled with a small-to-medium-sized drive motor (balancing its own light weight with the required torque). The goal is to achieve a lightweight design for robotic arms with a reach of 4 meters or more, ensuring compatibility with small agricultural machinery platforms and portability.

[0009] 1. Purpose of the invention

[0010] The core objective of this invention is to address the industry pain point that existing long-reach robotic arms cannot simultaneously achieve lightweight, high rigidity, and low driving torque. This invention provides a lightweight, high-rigidity long-reach robotic arm device and its collaborative control method. Through structural innovation, it achieves a lightweight design with a reach of 4 meters or more, can be mounted on small agricultural platforms, and possesses the characteristics of high rigidity, low driving torque, and portability for small agricultural vehicles, thus adapting to the harvesting needs of non-standardized orchards.

[0011] 2. Core Technology Principles

[0012] The core innovation of this invention is based on the parallel axis theorem in mechanics of materials and the geometric invariance of triangular structures, to discretize and equivalently reconstruct the optimal stress-bearing cross section of the circular beam of a traditional robotic arm:

[0013] 1) The annular cross-section is the ideal bending and torsional cross-section for the robotic arm. This invention uses multiple rods symmetrically arrayed along the outer side of the annulus to achieve the continuous stress characteristics of an equivalent annular beam through a "discrete layout of finite rods". At the same time, it abandons the solid / full annular structure and achieves maximum weight reduction through the fully through-hole design between the rods. Based on this basic configuration, variations can be generated, that is, the distance of individual discrete rods from the central axis can be increased, which can strengthen the rigidity in the direction of increasing distance and form a non-annular cross-section. However, the rods can still form at least one triangular structure in the cross-section. Considering the maximum torsional and bending resistance, any material arranged inside the annular beam cross-section is inefficient and not the optimal layout structure on the outermost ring. Therefore, any load-bearing structure added inside the basic configuration of this invention does not change the core stress path of this invention and is a non-substantial change.

[0014] 2) Based on the parallel axis theorem, the moment of inertia of a multi-bar truss structure with a triangular layout has an additional increment that is squared with the distance between the centroids of the layout, on the basis of the moment of inertia of a single bar. This can improve the bending resistance and lateral deflection resistance by tens of times without increasing the overall weight, breaking the vicious cycle of traditional single-bar arm structure of "thickening and strengthening to maintain rigidity → increasing self-weight → surging torque" from the structural root.

[0015] 3) In conjunction with the inclined cable auxiliary drive system, the large torque at the joint is converted into a small pulling force at the end of the cable through the lever arm amplification effect, further distributing more than 70% of the joint load torque, so that only a small conventional torque motor is needed to complete the drive under the long boom extension condition, completely solving the industry problem of long boom extension being unable to be driven.

[0016] 4) When used in conjunction with a multi-bar truss structure, the anti-torsion ring can not only limit the torsional deformation of the multi-bar parallel structure, but also divide a single rigid bar into multiple short bars, which can significantly increase the local buckling critical stress and local vibration natural frequency of a single bar, and suppress the risk of local instability and resonance of the bar.

[0017] The truss structure of this invention not only enables ultra-lightweight design under light load conditions, but also achieves load-bearing capacity and rigidity far exceeding that of traditional structures under the same weight by adjusting the specifications and spacing of the members, thus adapting to the full range of operational needs from light to heavy loads.

[0018] The core innovation of this invention lies in using a multi-bar parallel truss rigid load-bearing frame as the sole main load-bearing structure of the arm, completely eliminating the traditional technical path of relying on enclosed box-shaped wall panels for load bearing. This invention does not exclude the addition of protective and decorative enclosed structures that do not participate in the main load bearing outside the truss structure. Such additional structures do not change the core attribute of the truss as the main load-bearing structure and do not deviate from the protection scope of this invention.

[0019] The multi-bar parallel truss rigid force-bearing frame tandem robotic arm of this invention does not derive its rigidity solely from the rigid bars themselves, but rather from the overall structure formed by the rigid bars and the end-connector assembly. The end-connector assembly forcibly fixes the ends of multiple rigid bars together, forming a stable, geometrically invariant system in space, which is crucial for realizing the parallel axis theorem and achieving high stiffness. If the strength, stiffness, or connection method of the end-connector assembly is improperly designed, the entire frame will fail, with consequences more severe than those of a traditional single-tube arm—because a single-tube arm can still rely on its own tube wall for support, while the three individual bars of this invention will completely lose their load-bearing capacity once they lose their end constraints.

[0020] 3. Specific technical solutions

[0021] The high-rigidity, long-reach robotic arm device provided by this invention comprises multiple series-connected arm units and a drive assembly. It can be further equipped with a diagonal auxiliary drive system and an auxiliary mounting base. The specific solution is as follows:

[0022] 1) Core Arm Structure: The main body of the robotic arm consists of multiple arm units connected in series. Each arm unit includes a multi-bar parallel truss rigid load-bearing frame and an end-effector. The rigid load-bearing frame has a closed-loop profile containing at least one triangle in its cross-section and a fully open, hollow structure running through the front and rear. It is composed only of rigid members and the end-effector, without additional enclosed wall panels or internal load-bearing supports. This achieves lightweight design while ensuring torsional and bending resistance due to the inherent rigidity of the triangular structure. The end-effector is fixed to the end of the multi-bar parallel truss and has a matching connection structure. The drive assembly can be a joint torque motor, a hydraulic / pneumatic drive mechanism, or a combination thereof, assembled with the end-effector to drive the multiple arm units in series. The arm units can be arranged in a series configuration, such as vertical stacking, lateral stacking, or a combination thereof.

[0023] Furthermore, to improve the overall torsional resistance and rigidity of the robotic arm and protect the tubular components, it is preferable to add at least one set of anti-torsion rings in the middle of the main body of the robotic arm, which cooperate with the fixing plates of the end-connecting components at both ends of the robotic arm to improve torsional performance. For thin-walled rods in the arm body, an inner and outer protective tube can be added to the end of each rod to prevent the thin walls from being crushed during long-term operation. At the joint connection of the two robotic arms, a locking mechanism is set to lock the position after the robotic arm is twisted into place, connecting the entire robotic arm into a "near-whole" rigid component, thereby improving the overall rigidity and end-effector stability of the robotic arm.

[0024] 2) Inclined Auxiliary Drive System: This system includes a pull rope and a pull rope drive motor. One end of the pull rope is fixed to a preset fixed position on the boom, and the other end is connected to the winding mechanism of the drive motor. The tension is adjusted by winding the pull rope around the motor, and the lever arm amplification effect is used to provide auxiliary torque to the boom, sharing the load of the joint motor, offsetting the drive torque generated by its own weight and end load, and lowering the selection threshold for joint drive components.

[0025] 3) Auxiliary installation base: including a rotating gimbal turntable and an installation auxiliary frame. The robotic arm and the inclined pull auxiliary system are all installed on the gimbal turntable, which can achieve 0-360° horizontal rotation and is suitable for all-directional harvesting operations. The gimbal turntable is fixed on the installation auxiliary frame and can be directly fixed and assembled with the truck bed or carriage of the agricultural vehicle to achieve mobile operation with the vehicle.

[0026] 4) Cooperative control logic between the joint drive assembly and the cable-stayed auxiliary drive system:

[0027] By using the rotational angle data of the joint torque motor, the real-time posture of each arm body unit is obtained, and the theoretical joint driving torque under the corresponding posture is calculated.

[0028] When the arm extends from the retracted state, it starts to extend from the outermost arm unit first. The outermost arm unit can complete the torsional control of the entire swing angle range only through the joint torque motor, without the need for oblique pull auxiliary drive.

[0029] When deploying the remaining arm units, the torque margin of the joint torque motor is first determined based on the real-time posture. If the inclined pull is required, the joint torque motor and the inclined pull drive motor work together. The inclined pull drive motor adjusts the tension in real time to offset part of the torque of the corresponding joint, and the remaining torque is output by the joint torque motor to gradually complete the arm deployment. If the joint torque motor can be driven independently, the joint torque motor works alone, and the inclined pull drive motor only performs the rope winding and unwinding actions to maintain the basic tension of the rope to prevent tangling. When the arm is fully extended or a single arm unit is extended, the inclined pull bears no less than 70% of the load torque of the joint.

[0030] After the boom extends to the working position, the mechanical locking mechanism is triggered to lock the corresponding joints, so that the multi-section boom unit forms a rigid whole;

[0031] When the boom is retracted, the mechanical locking mechanism of the corresponding joint is unlocked first. During the retraction process, the lever arm corresponding to the maximum torque load is shortened first, the lever arm of the end working arm is shortened first, and the end boom is pulled back from the working space to avoid obstacles. The diagonal pulling force corresponding to each section of the boom is adjusted simultaneously to maintain the rope tension, and the boom retraction is completed.

[0032] Specifically, this invention provides a robotic arm device, comprising multiple arm segments and a drive assembly. The multiple arm segments are connected in series, and at least one arm segment is a rigid load-bearing frame formed by a multi-bar parallel truss and an end-mounted adapter assembly. The rigid load-bearing frame is formed by multiple parallel or substantially parallel rigid members enclosed by the end-mounted adapter assembly. The cross-section of the multi-bar parallel truss rigid load-bearing frame is a closed-loop profile containing at least one triangular structure, and the axial direction is a through-hole structure. The entire load-bearing structure within the frame is formed solely by the rigid members and the end-mounted adapter assembly. The end-mounted adapter assembly is fixedly connected to the end of the multi-bar parallel truss rigid load-bearing frame and has a connection structure adapted to the multi-bar parallel truss rigid load-bearing frame. The drive assembly includes a joint torque motor or a hydraulic / pneumatic drive structure or a combination thereof, used to drive the multiple arm segments in linkage. The drive assembly is assembled and connected to the end-mounted adapter assembly. The multiple arm segments can be arranged in a series configuration, such as vertical stacking, lateral stacking, or a combination thereof.

[0033] Furthermore, the rigid member is provided with at least one set of anti-torsion structures, which divide the single rigid member into equivalent short segments. The anti-torsion structures form at least one geometrically non-deformable structure by enclosure. The anti-torsion structure is any one or more combinations of the following: a combination structure of a ring structure and a rigid member, a cross-link structure, a frame structure, and a plate structure.

[0034] Furthermore, it also includes an inclined pull auxiliary drive structure, which includes a pull rope and a pull rope drive motor. One end of the pull rope is fixed to a preset pull rope fixing position on the arm unit, and the other end is connected to the winding mechanism of the pull rope drive motor. The pull rope drive motor adjusts the tension by winding the pull rope, and provides auxiliary torque to the arm unit by means of the lever arm amplification effect, sharing the load of the joint torque motor and offsetting the drive torque generated by the weight of the robotic arm and the end load.

[0035] Furthermore, it also includes an auxiliary mounting base, which is equipped with a rotating gimbal turntable. The robotic arm device and the inclined pull auxiliary drive structure are both mounted on the rotating gimbal turntable of the auxiliary mounting base.

[0036] Furthermore, the rigid members of the multiple boom units adopt a differentiated material layout. The rigid members of the boom unit near the auxiliary installation base are made of high-strength metal, while the rigid members of the boom unit far from the auxiliary installation base are made of low-density, high-strength material. The material combination can be freely adjusted according to the operational requirements.

[0037] Furthermore, the rigid members of the multi-bar parallel truss rigid load-bearing frame are rigid load-bearing profiles with closed or open cross sections, and can be any one or a combination of thin-walled tubes, thick-walled tubes, solid bars, coaxial nested composite tubes, channel profiles, and profiles with irregular cross sections; when the rigid member is a tubular or hollow profile, a crush-resistant protection structure is provided at the connection between it and the end transition assembly to disperse radial pressure and prevent tube wall deformation failure.

[0038] Furthermore, the cross-section of the multi-bar parallel truss rigid load-bearing frame is formed by three rigid members enclosing an equilateral triangle layout.

[0039] Furthermore, adjacent arm units are hinged by a rotary joint. The joint torque motor or hydraulic / pneumatic drive structure or a combination thereof is embedded in the rotary joint to drive the pitch and twist of the arm unit. The rotary joint is also equipped with a mechanical locking mechanism, which can lock the joint when the arm is extended to the working posture, so that the multiple arm units form a rigid whole, and unlock when the arm is retracted.

[0040] Furthermore, the rigid rod is assembled with the end adapter and adjacent arm units in a detachable connection structure, and can be disassembled into independent units for bulk transportation. It can be assembled and reconstructed on-site or in orbit, adapting to the full-scenario requirements of free adjustment of arm span and individual replacement of components.

[0041] The present invention also provides a method for the cooperative control of the above-mentioned robotic arm, comprising the following steps.

[0042] Step 1, Attitude Acquisition and Torque Calculation: The real-time attitude of each arm unit is acquired by using the rotation angle data of the joint torque motor, and the theoretical joint driving torque under the corresponding attitude is calculated.

[0043] Step 2, end-point priority deployment control: When the arm extends from the retracted state, it will prioritize the extension of the end arm unit. The end arm unit will only complete the torsional control of the full swing angle range through the joint torque motor, without the need to start the inclined pull auxiliary drive system.

[0044] Step 3, Multi-section Arm Coordinated Deployment Control: When deploying the remaining arm units, the torque margin of the joint torque motors is first determined based on the real-time posture. If diagonal pull assistance is required, the joint torque motors and diagonal pull drive motors work together. The diagonal pull drive motors adjust the tension in real time to offset part of the torque of the corresponding joints, and the remaining torque is output by the joint torque motors to gradually complete the arm deployment. If the joint torque motors can be driven independently, the joint torque motors work alone, and the diagonal pull drive motors only perform rope winding and unwinding actions to maintain the basic tension of the ropes and prevent tangling.

[0045] Step 4, Position Locking Control: After the boom extends to the working position, the mechanical locking mechanism is triggered to lock the corresponding joints, so that the multi-section boom unit forms a rigid whole;

[0046] Step 5, end-effector priority retraction control: When the arm retracts, first unlock the mechanical locking mechanism of the corresponding joint. During the retraction process, prioritize shortening the lever arm corresponding to the maximum torque load, prioritize shortening the lever arm of the end-effector, pull the end-effector back from the working space to avoid obstacles, and simultaneously adjust the diagonal pulling force corresponding to each section of the arm to maintain rope tension, thus completing the arm retraction.

[0047] Furthermore, in step 3, when the arm is fully extended or a single section of the arm is extended, the tension is adjusted by the inclined pull drive motor so that the inclined pull bears no less than 70% of the load torque of the joint.

[0048] One or more technical solutions provided by this invention have at least the following technical effects or advantages:

[0049] 1) Breaking through core industry contradictions and solving intractable pain points: Through innovative multi-bar triangular truss structure, the bending and lateral deflection resistance is improved by tens of times compared to a single thin bar under the same weight. Combined with a diagonal torque-sharing mechanism, the "torque explosion" problem of 4-meter long-arm robotic arms is completely solved. Only a small conventional torque motor is needed for drive, achieving a synergistic unity of long arm reach, lightweight, high rigidity, and low drive torque, breaking the vicious cycle of traditional technology where "long arms must be heavy-loaded, and heavy loads must have insufficient torque." This invention, through the triangular layout of multiple bars, utilizes the parallel axis theorem to achieve nonlinear enhancement of stiffness, breaking the traditional design paradigm of "linear correlation between stiffness and weight" for robotic arms, and providing a brand-new technical path for lightweight and high-rigidity long-arm robotic arms.

[0050] 2) Lightweight advantage over existing solutions, strong adaptability: The total weight of the core tandem arms with a 4-meter reach can be controlled within ten kilograms. The whole machine can be mounted on small agricultural platforms such as human-powered tricycles and electric tricycles without modifying the chassis. It is suitable for non-standardized operation scenarios in my country's vast traditional old orchards, with extremely low application threshold, filling the market gap for picking equipment in small orchards. This configuration can also be adapted to existing heavy-duty picking vehicles. By simply replacing the bottom support components and stacking the number, a multi-arm dense picking structure can be formed.

[0051] 3) Excellent structural anti-interference performance and strong operational stability: The fully open truss structure can significantly reduce the flutter of the arm caused by wind resistance and fluid impact, and has better wind resistance when operating in outdoor orchards, ensuring the accuracy of picking and positioning; the multi-bar layout combined with the anti-torsion ring structure has torsional and lateral deflection resistance far exceeding that of a single-tube arm of the same weight, and can effectively cope with complex working conditions such as orchard branch contact and eccentric picking.

[0052] 4) Strong scalability: Core performance is achieved through structural optimization, not relying solely on high-end materials such as carbon fiber. It can be adapted to various materials such as aluminum alloy, titanium alloy, steel, and composite materials, taking into account both high-end lightweight and low-cost large-scale requirements. At the same time, it can be seamlessly extended to scenarios such as short-arm light-load operation, industrial handling, underwater grasping, and aerospace robotic arm use, greatly enhancing patent value and industrialization potential.

[0053] The truss-type robotic arm structure of this invention has unparalleled advantages over traditional structures in special operating environments such as microgravity / zero gravity in space and underwater buoyancy offsetting gravity: In the space environment, the high rigidity-low weight ratio of the structure can significantly reduce the inertia of the arm's movement, making it suitable for a full range of operational needs, from light-load precision operations to heavy-load on-orbit construction; In the underwater environment, the hollow truss structure can significantly reduce water flow resistance and disturbance, and the rigid members can adopt a fully through-hole structure to achieve internal and external water pressure balance, eliminating the need for a pressure-resistant shell design. It can achieve both lightweight and high rigidity across the entire water depth range, making it suitable for all working conditions, from underwater exploration to heavy-load mining.

[0054] 5) Excellent dynamic characteristics: The truss structure of this invention can significantly increase the natural frequency of the robotic arm by improving the stiffness-to-mass ratio. Combined with the segmented reinforcement of the anti-torsion ring, it can effectively avoid low-frequency excitation in the working environment, reduce the risk of resonance, improve the fatigue life of the structure, and meet the dynamic characteristic requirements of harsh scenarios such as industrial high-frequency operation and aerospace launch vibration. Attached Figure Description

[0055] Figure 1 is a schematic diagram of the overall structure of the robotic arm in the bow-shaped retracted posture of the present invention;

[0056] Figure 2 is a structural schematic diagram of the single-section three-tube truss arm of the present invention;

[0057] Figure 3 is a schematic cross-sectional view of the inner and outer protective tubes at the end of the thin-walled tube described in this invention;

[0058] Figure 4 is a schematic diagram of the anti-torsion ring structure of the present invention;

[0059] Figure 5 is a schematic diagram of the mechanical locking mechanism of the present invention;

[0060] Figure 6 is a schematic diagram of the layout of the auxiliary mounting base and the inclined auxiliary drive system described in this invention;

[0061] Figure 7 is a schematic diagram of the fully extended horizontal inclined rope connection of the third section of the arm body according to the present invention;

[0062] Figure 8 is a schematic diagram of the fully extended horizontal inclined rope connection of the second section of the arm body according to the present invention;

[0063] Figure 9 is a schematic diagram of the fully extended horizontal inclined rope connection of the first section of the arm body according to the present invention;

[0064] Figure 10 is a schematic diagram of the folding and fruit-placing posture of the robotic arm in a heavy-duty vehicle scenario according to the present invention;

[0065] Figure 11 is a simplified structural diagram of the short-arm robotic arm described in this invention.

[0066] Figure 12 is a schematic diagram of the long-arm multi-joint lateral series structure of the present invention.

[0067] Explanation of reference numerals in the attached figures:

[0068] 1-1 First arm, 1-2 Second arm, 1-3 Third arm, 1-4 Fourth arm, 1-5 Pull rope, 1-6 End effector mounting auxiliary interface;

[0069] 1-1-1 Mounting frame with ears, 1-1-2 Mounting frame without ears, 1-1-3 First thin-walled tube, 1-1-4 Second thin-walled tube, 1-1-5 Third thin-walled tube, 1-1-6 Pull rope fastener, 1-1-7 Robotic arm joint motor, 1-1-8 Outer wall protective tube, 1-1-9 Inner wall protective tube, 1-1-10 Anti-torsion ring, 1-1-11 Annular toothed disc, 1-1-12 Electric telescopic drive assembly, 1-1-13 Moving toothed plate;

[0070] 2-1 Auxiliary column, 2-2 Guide pulley, 2-3 Winding roller, 2-4 Drive motor, 2-2-1 First guide pulley, 2-2-2 Second guide pulley, 2-2-3 Third guide pulley, 2-3-1 First winding roller, 2-3-2 Second winding roller, 2-3-3 Third winding roller, 2-4-1 First drive motor, 2-4-2 Second drive motor, 2-4-3 Third drive motor;

[0071] 3-1 Gimbal turntable; 3-2 Install auxiliary frame. Detailed Implementation

[0072] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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.

[0073] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0074] 1. Overall Structure Overview

[0075] The high-rigidity, long-reach robotic arm device of the present invention has the following overall structure: Figure 1 As shown, the core consists of three main parts: a multi-section, series-connected boom body, an inclined cable auxiliary drive system, and an auxiliary mounting base.

[0076] The arm body is preferably composed of four arm units connected in series. The length of a single arm unit is preferably 1m, and the total arm span is 4m when straightened. This can meet the full height coverage and harvesting needs of traditional orchards with trees 2.5 meters high and canopy radius of 3 meters. The four arm units are hinged by mounting ears at the ends of the front arm units. When folded, they are stacked in a bow shape, maximizing the saving of storage and transportation space and meeting the needs of small agricultural platforms.

[0077] Two adjacent arm body units are hinged through a rotary joint, and a small-sized high-torque drive motor (i.e., joint torque motor) is built in the rotary joint to realize the pitching and torsional drive of the arm body; a mechanical locking mechanism is arranged near the motor rotating shaft of the rotary joint. When the arm body is unfolded to the working posture, the locking mechanism is powered on to perform the locking action, locking the joint to make the multi-section arm body form an approximately rigid whole, strengthening the joint connection rigidity; when the arm body is folded, the locking mechanism is powered off to unlock, and the arm body can be freely rotated and recovered.

[0078] At the end of the arm body unit at the outermost end of the robotic arm, an installation auxiliary interface for the picking actuator is provided, which can be adapted to conventional picking actuating mechanisms such as bionic manipulators and pruning shears; at the ends of the remaining arm bodies except the outermost end arm body, cable fixing parts are provided to connect to the stay cable auxiliary drive system to realize the hierarchical sharing of joint torque.

[0079] This configuration is an optimized design based on the vertical series layout of the robotic arm. The series layout of the arm body units of the present invention includes, but is not limited to, the above-mentioned vertical stacking layout, and can also adopt a direct stacking, lateral stacking or a combined series layout form. Its core truss structure, connection logic, lightweight and high-rigidity technical effects are completely consistent with those of the embodiment, and those skilled in the art can freely adjust the layout form according to actual operation requirements.

[0080] 2. Core structure of a single-section arm body

[0081] Each arm body unit jointly forms a rigid force-bearing framework with a multi-bar parallel truss and an end connection component. Preferably, 3 parallel hollow thin-walled tubes are arranged in the simplest configuration of an equilateral triangle in parallel. In practice, it can be further expanded to more than 3, and the pipe diameter can be correspondingly reduced and the pipe wall can be thinned to reach or even exceed the mechanical properties of the 3-pipe arm; both ends of the arm body are fixedly connected through a double-wall plate in the shape of a Chinese character "ri" or a near-"ri" shape (i.e., an end transfer component) to form an integrated truss structure. The double-wall plate configuration in the shape of a Chinese character "ri" is a frame structure as a whole, and the middle wall plate is arranged close to the front side. Preferably, the front wall plate is thicker than the middle and rear wall plates. Holes are opened on the double-wall plates of the front and middle wall plates to be fixedly connected and配合 with the three thin-walled tubes, rigidly clamping the three thin-walled tubes. The double-plate clamping + spacing forms a short beam constraint, and the effect is equivalent to that each thin-walled tube is "fixed at both ends" at the end, equivalent to forming a rigid constraint section at the end, making the thin-walled tube hardly rotate or slip. The bending moment in the double plates is mainly borne by the front plate, which requires a thicker size and greater rigidity. The rear plate is mainly responsible for positioning, clamping, anti-pulling, etc., focusing on shear resistance and tensile resistance. In order to minimize the weight, the upper and lower surfaces of the end transfer component in the shape of a Chinese character "ri" can be not provided with wall plates, and it is a through structure from top to bottom. A joint motor and a mechanical locking structure are arranged in one of the uninserted port-shaped structures of the double "ri" shapes. The structure of a single-section arm body is as Figure 2 shown.

[0082] The material of the rigid rod can be selected according to the working conditions, preferably high-strength carbon fiber tube or 7075-T6 aluminum alloy thin-walled tube; the multi-section boom can adopt a differentiated material layout: the first and second load-bearing sections of the boom at the near end (close to the gimbal) are made of aluminum alloy to ensure rigidity; the third and fourth lightweight sections of the boom at the far end (close to the actuator) are made of carbon fiber to reduce weight, taking into account both overall rigidity and lightweight requirements.

[0083] The rigid rod can also be a channel profile, an irregular cross-section profile, or a coaxial nested composite structure, including an inner circular tube and an outer triangular or square cross-section tube. The inner circular tube is made of carbon fiber, and the outer triangular or square cross-section tube is made of thin-walled aluminum alloy. The inner circular tube is inserted into the outer tube to form a single composite rigid rod. This structure can take into account the torsional resistance and lightweight advantages of the inner carbon fiber and the bending resistance and easy processing advantages of the outer aluminum alloy. The other cross-section tubes can be hollow tubes with internal reinforcing ribs, for example, cross-shaped or star-shaped ribs are set on the inner wall of the round or square tubes to improve local stability.

[0084] Furthermore, since the multi-strut parallel truss rigid load-bearing frame is composed of simple-shaped members and joints, it can be standardized, customized, and mass-produced. Standardized detachable connection structures such as threaded connections, quick-connect interfaces, and bolted connections can be used between the rigid members and the end adapter components, as well as between adjacent boom units. This allows for bulk transportation, rapid on-site assembly, free adjustment of boom extension, and individual component replacement, effectively reducing transportation and maintenance costs. For preferred connection methods, please refer to the descriptions of modular splicing in Embodiments 4 and 11. The thin-walled tube structure can be bolted to the load-bearing frame through inner and outer protective tubes, enabling rapid on-site assembly of boom components.

[0085] Within the multi-bar parallel truss rigid load-bearing frame of this invention, auxiliary structures that do not participate in the main load-bearing can be added, such as sensor brackets, cable fasteners, and lightweight protective covers. The addition of these auxiliary structures does not change the core force path of the rigid members, nor does it affect the essence of the technical solution of this invention. They are conventional design choices for those skilled in the art and should not be considered as an effective means of circumventing the patent rights of this invention.

[0086] 3. Anti-crushing protective structure

[0087] When rigid members are made of thin-walled tubular components, the connection between them and the end adapter assembly is equipped with an inner and outer protective tube. These tubes are used to distribute the radial pressure on the thin-walled tube during structural restraint and load-bearing operations, preventing the tube from crushing. Figure 3 As shown.

[0088] The outer protective tube is fitted onto the outer wall of the thin-walled tube at the end and is press-fitted to the thin-walled tube by an elastic rubber gasket. The end of the outer protective tube is provided with a small flange and is fixed to the H-shaped double wall plate by screws. The inner protective tube is embedded in the inner wall of the thin-walled tube at the end and is fixed by adhesive (for carbon fiber tubes) or screws (for aluminum alloy tubes), forming double protection with the outer protective tube.

[0089] The protective tube is made of high-strength aluminum alloy, which can effectively solve the industry pain points of stress concentration and easy crushing at the ends of thin-walled tubes, and greatly improve the service life and operational reliability of the boom.

[0090] The anti-crushing protection structure, in addition to being an attachment independent of the rigid rod and the end adapter assembly, can also be a structure integrally formed with the rigid rod or the end adapter assembly, such as a smooth transition fillet, a gradually increasing wall thickness section, or a reinforcing rib provided at the connection. As long as the structure can effectively disperse the radial pressure at the connection and prevent the pipe wall from crushing or deforming due to stress concentration, it falls within the protection scope of this invention.

[0091] 4. Anti-torsion ring structure

[0092] Preferably, a set of anti-torsion ring structures is provided in the middle of the single-section arm body, as shown in Figure 4, to limit the torsional deformation of the three-tube parallel structure, improve the anti-torsion performance and rigidity of the arm body, and ensure that the anti-chatter and anti-torsion performance of the robotic arm in the unfolded posture meets the positioning accuracy requirements of the end effector.

[0093] The anti-torsion ring is a thin-walled circular ring that matches the number of rigid rods. The circular ring is interference-fitted with the outer wall of the rigid rod through an elastic rubber gasket. The three circular rings are fixedly connected by three rigid connecting rods. When the number of rigid rods is greater than 3, the circular rings of the anti-torsion ring and the connecting rods form at least one triangular geometrically non-deformable structure to ensure the anti-torsion effect.

[0094] The anti-torsion ring is a non-load-bearing auxiliary structure. After its removal, the frame can still meet the stress requirements under rated working conditions. It does not change the core stress path of the three-tube truss, nor is it a load-bearing support component inside the frame.

[0095] The specific structural form of the anti-torsion ring can be flexibly adjusted. As long as it can form a geometrically non-deformable structure by enclosure and achieve the functions of limiting torsional deformation and separating long rods, it falls within the protection scope of this invention, including but not limited to the combination of ring structure and connecting rod, cross-shaped connecting rod, integrated frame, plate structure, and other equivalent structures.

[0096] The cross-link structure can consist of two links fixed at the midpoint, with each end connected to an adjacent rigid member of the arm, thus forming a geometrically invariant system. The frame structure includes, but is not limited to, a frame structure where the cross-links are replaced with square tubes connected in a cross pattern, which can be used to support the torsional rigidity of a four-arm configuration. The plate structure includes, but is not limited to, thin plates with triangular cross-sections, with perforations to accommodate the torsional rigidity of a three-tube configuration. Although the above torsional rigidity structures differ in form, they all form a geometrically invariant system through enclosure, achieving the functions of limiting the torsional deformation of the multi-link parallel structure of the arm and separating long links to improve local stability. These are equivalent embodiments of the torsional rigidity structure of this invention.

[0097] 5. Mechanical locking mechanism

[0098] The mechanical locking mechanism includes an annular toothed disc, an electric telescopic drive assembly, and a movable toothed plate. The annular toothed disc is coaxially fixed to the shaft of the joint motor, and the electric telescopic drive assembly is fixed to the joint housing. After the arm is in position, the electric telescopic drive assembly extends, driving the movable toothed plate to engage with the annular toothed disc, thus achieving mechanical locking of the joint. When the arm is retracted, the electric telescopic drive assembly retracts, disengaging the engagement and allowing the joint to rotate freely. The annular toothed disc is screwed and fastened to the inside of the mounting ears of the ear-mounted frame, which is part of the end-cap adapter assembly. Its position is shown in Figure 5.

[0099] The worm gear joint motor with built-in mechanical self-locking function after power failure is preferred. Combined with the electromagnetic locking mechanism, a dual locking mechanism of "motor self-locking + external locking" is formed, which can further limit the small displacement of the joint and greatly improve the structural stability and end-positioning accuracy of the multi-section arm connected in series.

[0100] 6. Cable-stayed auxiliary drive system

[0101] The inclined pull auxiliary drive system includes a pull rope, guide pulleys, winding rollers, a pull rope drive motor, and an auxiliary column. The auxiliary column is vertically fixed on the rotating gimbal turntable. The guide pulleys are fixed at the top of the auxiliary column, and the number of sets is one less than the number of robot arm sections. The pull rope drive motor adopts a dual-shaft structure, with a winding roller installed at the end of each shaft. The winding rollers are mounted on the auxiliary column through bearings. The winding rollers are located below the guide pulleys, and their number matches the number of guide pulley sets.

[0102] One end of the pull rope is tied to the pull rope fixing piece at the end of the corresponding arm body, and the other end is wrapped around the winding roller after passing over the guide pulley. The guide pulley and the winding roller are used in pairs on the auxiliary column, and the extension height is distributed in a stepped manner to ensure that multiple sets of pull ropes work in different planes without interfering with each other or getting tangled.

[0103] Each boom section is equipped with two symmetrically arranged diagonal braces. The two braces are connected to opposite sides of the distal end of the boom, forming a symmetrical traction structure to prevent boom twisting caused by unilateral traction. During operation, the braces drive a motor to rotate the winding rollers, providing auxiliary tension against the boom's own weight and load through the diagonal braces, thus sharing the joint torque and reducing it to a level that a small motor can withstand. The diagonal brace auxiliary system is distributed in the boom retraction structure and segment-by-segment after each boom section is deployed as follows: Figure 6 to Figure 9 As shown.

[0104] 7. Auxiliary installation base

[0105] The auxiliary mounting base includes a rotating gimbal turntable and a mounting auxiliary frame, as shown in Figure 6. The rotating gimbal turntable is installed on the upper part of the mounting auxiliary frame, which adopts a horizontal and vertical beam structure and can be directly fixed to the truck bed or cargo box of the farmer's existing agricultural tricycle, electric tricycle, or four-wheeled vehicle by bolts, without the need to modify the agricultural machinery itself.

[0106] An auxiliary column is fixed on the platform of the rotating gimbal. The bottom of the auxiliary column has an extended mounting structure for hinged connection of the first arm section. The bottom of the gimbal is equipped with a rotary drive motor, which can drive the robotic arm to achieve 0-360° horizontal rotation, adapting to the needs of all-directional harvesting operations.

[0107] Example 1:

[0108] Core implementation example of harvesting extra-large (heavy) fruits with a 4-meter-long arm span.

[0109] This embodiment addresses the harvesting scenario of oversized fruits such as apples, pears, and peaches in northern orchards. It is adapted to the extreme and harsh working conditions of a 4m arm in a fully extended horizontal posture, a maximum single fruit load of 1kg, and an actuator load of 0.5kg, i.e., an end-effector load of 1.5kg. Other arm structure parameters are as follows. This static calibration assumes the robotic arm is in a fully extended horizontal extreme condition, neglecting the influence of lightweight structures such as anti-torsion rings and tension ropes (which account for a very small percentage of weight) on joint torque. The calculation results are conservative but comply with mechanical design safety verification specifications.

[0110] In the following calculations, the results involving π, square roots, and division are all rounded to 1-3 decimal places. The torque units used in this paper are the commonly used engineering units kgf⋅m and kgf⋅cm. The conversion relationship with SI units is 1 kgf⋅m = 100 kgf⋅cm = 9.8 N⋅m. The same principle is followed in subsequent examples.

[0111] 1. Robotic Arm Structure Parameters: Total length 4m, divided into 4 sections (1m long per section); the two proximal sections use φ40mm×3mm 7075-T6 aluminum alloy round tubes, and the two distal sections use φ35mm×3mm 3K carbon fiber round tubes; the three round tubes are arranged in an equilateral triangle (side length 80mm), and are fixed by a reinforced nylon H-shaped frame. The end face of the clamping wall panel is a square with a side length of 140mm, which can cover the three-tube layout; to improve the rigidity and stability of the arm, this embodiment also preferably adds a set of anti-torsion rings at the middle length of the arm, and two sets of mechanical locking mechanisms are symmetrically arranged at the mounting ears of the end adapter assembly, the detailed structure of which is shown in Embodiment 4. The weight of the end adapter assembly has been included in the subsequent estimation according to an appropriate proportion of the weight of the arm components, and the subsequent weight parameters are calculated based on the weight of the main load-bearing components and an appropriate weight increment.

[0112] 2. Weight parameters:

[0113] General formula for calculating the weight per meter of a circular tube: D is the outer diameter of the pipe (in mm), t is the wall thickness of the pipe (in mm), and ρ is the material density (in g / cm³). The density of 7075-T6 aluminum alloy is ρ=2.81g / cm³, and the density of 3K carbon fiber is ρ=1.55g / cm³.

[0114] 1) Weight per meter of a single φ40×3mm aluminum alloy tube:

[0115]

[0116] The total weight of 3 aluminum alloy tubes per meter is 2.943 kg, and the weight of a single arm section after adding connectors is calculated to be 3.5 kg.

[0117] 2) Weight per meter of a single φ35×3mm carbon fiber tube:

[0118]

[0119] The total weight of 3 carbon fiber tubes per meter is 1.401 kg, and the weight of a single arm section after adding connectors is calculated to be 2 kg.

[0120] 3) The joint motor is a worm gear motor with a rated torque of 3kgfm. This type of motor has a power-off self-locking capability. The weight of a single unit is 1.15kg, and the total weight of 4 units is 4.6kg. The total weight of the robotic arm body + joint motor = 2×3.5kg + 2×2kg + 4.6kg = 15.6kg.

[0121] 4) The total weight of the auxiliary structure and cable-stayed system is calculated as follows:

[0122] The auxiliary support column is made of the same material as the arm body, with a U-shaped aluminum alloy frame (wall thickness 5mm) and dimensions of 142×100×1000mm;

[0123] The mounting bracket is made of the same material as the boom body, consisting of two 50×50×5mm aluminum alloy square tubes (1600mm in length), with two reinforcing ribs connecting the middle of the square tubes and both sides of the gimbal.

[0124] Gimbal body: Double-layered φ260mm×10mm aluminum alloy round plate;

[0125] Total weight of auxiliary structures: All the above structures are made of aluminum alloy, with a total weight of approximately 15.3 kg (excluding the inclined motor).

[0126] Weight of the inclined cable auxiliary system: It is equipped with 3 worm gear motors with a rated load torque of 1kgfm (0.42kg / unit), and the gimbal motor is selected as 1 single-axis model with the same parameters (to bear horizontal torsion, 0.42kg / unit); the total weight of the inclined cable auxiliary drive system + auxiliary mounting base is about 16.98kg; the weight of lightweight small structural components such as cable, pulley, and winding roller accounts for a very small proportion and is temporarily ignored.

[0127] The entire machine weighs 32.58 kg and can be directly mounted on a small agricultural tricycle. The overall robotic arm retracts into an arc shape. Figure 1 As shown, the configuration of different arm sections and inclined ropes after full deployment is as follows: Figures 7-9 As shown.

[0128] 3. Extreme operating condition torque verification:

[0129] The core calculation formula is: Joint driving torque = Σ (corresponding component weight × horizontal lever arm from the component's center of gravity to the current joint). In the fully flattened state, the lever arm is the straight horizontal distance from the component's center of gravity to the joint.

[0130] 4. Calculation order: Starting from the fourth joint (J4) at the very end and working backwards to the first joint (J1) at the root, this demonstrates the industry pain point of the conventional solution, "torque increases exponentially with arm extension," and compares it with the solution of this invention.

[0131] (1) The fourth joint (J4, connecting the third and fourth arms)

[0132] This joint only needs to drive the weight of the fourth arm plus the end load, without any subsequent arm stacking, making it the joint with the least torque.

[0133] Force-bearing components and lever arms:

[0134] The total load at the end is 1.5 kg, and the lever arm is 1 m (distance to joint J4).

[0135] The fourth arm weighs 2kg, with its center of gravity at the midpoint of the arm body, and its lever arm is 0.5m.

[0136] Original drive torque without slalom assist:

[0137]

[0138] The torque did not exceed the motor's rated torque. It can be driven independently using only a joint motor, without the need for a slant pull.

[0139] (2) The third joint (J3, connecting the second and third arms)

[0140] This joint needs to drive the weight of the third arm + the entire weight of the fourth arm + the end load. The force-bearing components and lever arms are as follows:

[0141] The total load at the end is 1.5 kg, and the lever arm is 2 m (distance to joint J3).

[0142] The motor of the fourth arm joint weighs 1.15 kg and has a lever arm of 1 m.

[0143] The fourth arm weighs 2kg and has a lever arm length of 1.5m.

[0144] The third arm weighs 2kg, with its center of gravity at the midpoint of the arm body, and its lever arm is 0.5m.

[0145] Original drive torque without guide rope assistance:

[0146]

[0147] Without the inclined pull assist, the total torque of the third arm joint is the rated torque of the motor (3 2.7 times that of the existing miniaturized installation space, there is no suitable conventional low-torque motor to drive it. The traditional solution has encountered the problem of "no motor to choose from" (no industrial and commercial motors suitable for miniaturized installation space) unless the installation space is expanded and a larger and heavier motor is selected, but this will lead to a surge in the torque demand of the subsequent arm joint motor.

[0148] The remaining torque after the inclined cable assistance of this invention, the inclined cable structure is as follows Figure 7 As shown, the stay cable bears 70% of the load torque. According to the lever arm balance relationship, the vertical component of the force on the stay cable is 8.15 × 70% / 1 = 5.71 kg (the lever arm is taken as the total length of the third arm, 1 m; see [reference]). Figure 7 The remaining 30% is handled by the joint motor, which is fully compatible with the selected 3kgfm torque motor.

[0149]

[0150] After the inclined cable assists share 70% of the torque, the remaining torque of the joint is controlled within 2.5 kgf·m, which can be fully adapted to the selected 3 kgf·m torque motor.

[0151] The cable is 3.43m long and has a vertical projection height of 0.73m. Based on trigonometric calculations, the angle between the cable and the horizontal is 12.3°. The vertical component of the cable is 5.71kg. Combining this with the 12.3° angle, the total required tension is 5.71 / sin(12.3) = 26.8kg. This design uses two cable ropes to share the load, reducing the required tension per rope to 13.4kg. For high-strength nylon ropes (such as Dyneema and Kevlar), using fine wires with a diameter of 0.2-0.5mm, the breaking strength can reach 50-150kg. A tensile force of 13kg only accounts for 8.6%-26% of its rated breaking strength, which is an extremely light load. For fine steel wires (such as 0.3-0.8mm stainless steel wire rope), the breaking strength can reach 80-300kg. A tensile force of 13kg only accounts for 4.3%-16% of its rated breaking strength, which is almost negligible. Any of the above-mentioned preferred materials can meet the requirements for inclined cable pulling.

[0152] To meet the total pulling force requirement of 26.8kg, the inclined pull mechanism uses an inclined pull motor with a torque of 1kgfm (lever arm of 1cm), which can generate an inclined pull force of 100kg, thus satisfying the pulling force requirement.

[0153] (3) Second joint (J2, connecting the first and second arms)

[0154] This joint needs to drive the weight of the second arm plus the total weight of the third and fourth arms, plus the end load, further amplifying the torque, making traditional solutions completely ineffective. Force-bearing components and lever arms:

[0155] The total load at the end is 1.5 kg, and the lever arm is 3 m (distance to joint J2).

[0156] The combined weight of the motors for the 4th and 3rd arm joints is 2.3 kg, and the single lever arms are 2 m and 1 m respectively;

[0157] The combined weight of the 4th and 3rd arms is 4kg, with center of gravity lever arms of 2.5m and 1.5m respectively;

[0158] The second arm weighs 3.5 kg, with its center of gravity at the midpoint of the arm body, and its lever arm is 0.5 m.

[0159] Original drive torque without guide rope assistance:

[0160]

[0161] This torque is 5.9 times the rated torque of the motor. Under the same installation space constraints as the 3rd and 4th arm sections, there is no motor on the market that can meet this torque requirement while also being small and lightweight. Forcing the selection of a high-torque motor will lead to an increase in joint space and arm weight, further exacerbating the torque burden on subsequent joints and creating a vicious cycle.

[0162] By superimposing a cable-stayed torque-sharing mechanism, a new Figure 8 The cable shown has its torque shared by the second and third arms (the third arm cable has a vertical tension of 5.71 kg and a lever arm of 2 m). The second arm cable in this stage then bears 70% of the remaining torque, resulting in the following final remaining torque:

[0163]

[0164] This torque is perfectly compatible with the selected 3kgfm torque motor.

[0165] The second arm adds a new inclined cable for load sharing: this inclined cable is approximately 2.386m long, with a vertical projection height of approximately 0.694m. Based on trigonometric calculations, the angle between the cable and the horizontal direction is approximately 16.9°. Its core function is to bear 70% of the torque remaining after deducting the torque sharing from the third arm's inclined cable (17.7 - 5.71 × 2 = 6.28 kgf·m). Force analysis yields a required vertical component force of 6.28 × 70% / 1 = 4.40 kg. Combining this with the 16.9° angle, the total required tension for the inclined cable is calculated to be 4.40 / sin(16.9) = 15.14 kg. This design uses two inclined cables to share the load, reducing the required tension for a single cable to 7.57 kg. The second arm's inclined cable uses the same parameters as the third arm, and the motor fully meets this tension load requirement.

[0166] (4) Joint 1 (J1, connecting the first arm and the gimbal, root joint)

[0167] This joint needs to drive the entire weight of the arm plus the end load, which is the torque peak bottleneck of traditional solutions.

[0168] Force-bearing components and lever arms:

[0169] The total load at the end is 1.5 kg, and the lever arm is 4 m (distance to joint J1).

[0170] The combined weight of the motors for the 4th, 3rd, and 2nd arm joints is 3.45 kg, and the individual lever arms are 3 m, 2 m, and 1 m respectively.

[0171] The combined weight of arms 4, 3, and 2 is 7.5 kg, with center-of-gravity lever arms of 3.5 m, 2.5 m, and 1.5 m, respectively.

[0172] The first arm weighs 3.5 kg, with its center of gravity at the midpoint of the arm body, and its lever arm is 0.5 m.

[0173] Original drive torque without slalom support:

[0174]

[0175] This torque is 10.6 times the rated torque of the motor, which completely exceeds the engineering implementation limit of miniaturized motors. Traditional solutions are completely ineffective here, and large motors must be used to drive it. For small farmers picking fruit in their orchards or using small agricultural machinery, it is not practical in terms of weight and power consumption.

[0176] By superimposing a cable-stayed torque-sharing mechanism, a new Figure 9 The inclined cable shown is supported by the torque sharing of the first arm in conjunction with the third and second arms (the third arm's inclined cable has a vertical tension of 5.71 kg and a lever arm of 3 m; the second arm's inclined cable has a vertical tension of 4.40 kg and a lever arm of 2 m). The first arm's inclined cable then bears 70% of the remaining torque, resulting in the following final remaining torque:

[0177]

[0178] This torque is perfectly compatible with the selected 3kgfm torque motor.

[0179] The first arm features a newly added inclined cable for load sharing: This cable is approximately 1.44m long, with a vertical projection height of approximately 0.814m. Based on trigonometric calculations, the angle between the cable and the horizontal direction is approximately 34.4°. Its core function is to bear 70% of the torque remaining after deducting the torque sharing from the third and second arm inclined cables (31.9 - 5.71 × 3 - 4.4 × 2 = 5.97 kgf·m). Force analysis yields a required vertical component force of 5.97 × 70% / 1 = 4.18 kg. Combining this with the 34.4° angle, the total required tension for the inclined cable is calculated to be 4.18 / sin(34.4) = 7.40 kg. This design employs two inclined cables for coordinated load sharing, reducing the required tension of a single cable to 3.70 kg. The first arm's inclined cable uses the same parameters as the third and second arms, and the motor fully meets this tension load requirement.

[0180] Based on the above calculations, the summary table of torque comparisons across all joints is shown in Table 1. It is evident that when the robotic arm is lengthened, even with the weight reduction achieved by the joint arm of this invention, the traditional solution's joint driving torque exceeds the motor's limit starting from the third joint, rendering it unable to drive from this midpoint, resulting in an industry deadlock. In contrast, the method of this invention, after torque reduction, perfectly matches the selected motor, fundamentally breaking the vicious cycle of "torque explosion" in the torque drive requirements of long-reach joints in multi-joint series robotic arms. This allows for drive capability with only a small, conventional torque motor under long-reach conditions, completely solving the industry problem of the inability to drive long-reach robotic arms.

[0181]

[0182] Table 1

[0183] In this embodiment, the weight of the end-cap adapter component has been estimated as a suitable proportion of the boom member weight and has not been modeled separately. In actual engineering implementation, the material, wall thickness, and installation structure can be adjusted according to the strength requirements of the working conditions, as detailed in Embodiment 4. This weight adjustment only changes the absolute value of the joint torque and does not change the core technical logic of 'exponential amplification of torque under long boom extension and the ability of the inclined cable auxiliary system to share more than 70% of the load torque'. The joint torque after torque reduction can still be fully adapted to the selected rated torque motor, and the core technical effect of this invention is not affected in any way.

[0184] Example 2:

[0185] A 4m-class robotic arm is used in small agricultural vehicles to prevent rollover and tipping.

[0186] This embodiment focuses on the core scenario of the robotic arm of the present invention being mounted on a small agricultural platform, verifying its anti-rollover stability under extreme working conditions, and ensuring its compatibility with lightweight mounting platforms such as human-powered tricycles and electric tricycles commonly used in small-scale orchards in my country.

[0187] 1. Calculation prerequisites and general formulas

[0188] The general formula for calculating the static rollover stability coefficient of agricultural machinery after installation is adopted, with the fully flattened horizontal posture as the most unfavorable working condition. The core formula is as follows:

[0189] Total roll moment: ,in This refers to the weight of the corresponding component. The horizontal lever arm is the distance from the center of gravity of the component to the center line of the truck bed.

[0190] Total system weight: ,in To accommodate the vehicle's own weight, The total weight of the robotic arm system. For end load;

[0191] Lateral offset of center of gravity: ;

[0192] • Stabilizing lever arm: ,in The width of the truck bed;

[0193] • Static stability coefficient: Industry-standard judgment criteria: S is generally considered to be F <1 indicates instability or criticality (S F <0, meaning rollover, S F =0 is the critical rollover point), 1≤S F <1.5 indicates basic stability, 1.5≤S F <3 indicates stability, S F A value of ≥3 indicates very stable performance.

[0194] 2. Basic parameter settings

[0195] The structure and weight parameters of the robotic arm are completely consistent with those of Example 1; the total weight of the robotic arm system is 32.58 kg, and the maximum load at the end is 1.5 kg; it covers four typical working conditions of commonly used vehicle types for farmers: vehicle weight 80 kg (human-powered tricycle) / 140 kg (electric tricycle), and the width of the cargo bed is 1.2 m / 1.5 m.

[0196] Step 1: Calculate the total weight and total roll moment of the system.

[0197] Total system weight:

[0198] kg

[0199]

[0200] Total roll moment:

[0201]

[0202] Step 2: The calculations for the four operating conditions are shown in Table 2.

[0203]

[0204] Table 2

[0205] From the above calculations and comparisons, it can be seen that the robotic arm provided by the embodiments of the present invention can ensure no static rollover when performing horizontal flattening operations under the worst working conditions, even for the lightest vehicle (80kg) and the narrowest cargo bed (1.2m), but the stability coefficient is relatively low.

[0206] For an 80kg human-powered tricycle, considering that dynamic working conditions such as inclined roads and potholes may reduce actual stability, in order to maintain a higher anti-rollover safety factor, counterweights can be added to both sides of the vehicle body. That is, sandbags or other counterweights can be hung on the outside of the truck bed and near the auxiliary mounting base. Adding 30-35kg to each side will increase the overall weight by 60-70kg, which is basically equivalent to the weight in working condition 3. Sand is readily available in orchard operations, requiring no additional procurement costs, and the safety factor can be easily and inexpensively improved to a high level.

[0207] In summary, under both static and dynamic conditions in rural orchards, the present invention can guarantee a sufficient safety factor, ensuring the safe operation of the robotic arm with the parameters described in this embodiment in orchard settings.

[0208] Example 3:

[0209] The length of the inclined rope and the selection of the inclined motor.

[0210] The preferred parameters for the inclined rope in this embodiment are as follows:

[0211] For the inclined rope rollers, choose "H"-shaped rollers made of 304 stainless steel, and compare their outer diameters. (i.e., the outer diameter after the rope is fully wrapped), inner diameter (i.e., without rope wrapping) Two working conditions are available: 20mm / 8mm and 30mm / 10mm, with roller width (thickness). All are 10mm;

[0212] · Rope diameter Choose a common 0.5mm high-strength nylon rope (balancing strength and rope allowance).

[0213] Formula for total rope length:

[0214] Average circumference per lap , The inner diameter of the roller. Roller outer diameter;

[0215] Number of rope turns per layer , For the width of the roller, The diameter of the rope;

[0216] Number of rope layers .

[0217] The calculation of the amount of rope for the two roller specifications is shown in Table 3.

[0218]

[0219] Table 3

[0220] The front robotic arm has a length of 4m. The exposed cable at the farthest end (the third arm section) needs to be 3.43m long. The rollers of this cable are closest to the pulley, about 0.061m away. The total cable length of 3.49m is sufficient to meet the total span requirement of the cable. The selected parameters meet the application requirements.

[0221] In Example 1, the robotic arm is in a horizontal position as the worst working condition, with an end load of 1.5kg. The tension of the three sets of inclined ropes is 26.8kg, 15.14kg, and 7.39kg, respectively. The selected motor has a torque of 1kgfm and a weight of 0.42kg.

[0222] Based on a roller outer diameter of 20mm after winding the rope (the minimum possible outer diameter, corresponding to the most stringent lever arm conditions), the maximum torque required by the stay rope motor is 26.8kg × 0.01m = 0.268kgf⋅m to meet the stay rope requirements under the most severe working conditions. The selected motor has a rated torque of 1kgf⋅m, which fully meets the drive requirements of the three stay ropes and leaves sufficient margin.

[0223] Example 4:

[0224] Calculation of selection for other components related to the robotic arm.

[0225] 1. Anti-torsion ring

[0226] For the robotic arm described in Example 1, two sets of anti-torsion rings (two sets in each set) are provided, which are installed at the two proximal sections and the two distal sections of the robotic arm, respectively. Each set of anti-torsion rings is sleeved in the middle of the three circular tubes in the corresponding section.

[0227] Proximal anti-torsion ring assembly: Suitable for arm body round tubes (aluminum alloy, 3mm wall thickness) with an outer diameter of φ40mm. It consists of three rings, preferably made of 7075-T6 aluminum alloy, with specifications of an outer diameter of φ45mm, a wall thickness of 2mm (inner diameter φ41mm), and an axial length of 20mm. The three rings are fixedly connected by connecting rods, forming the three vertices of an equilateral triangle, with a center-to-center distance of 80mm, matching the parallel spacing of the three round tubes. Each ring is fitted with a 1mm thick silicone rubber gasket between it and the corresponding arm body round tube, using an interference fit (0.2-0.3mm) to the outside of the round tube, as shown in the image. Figure 4 As shown.

[0228] Distal anti-torsion ring assembly: Suitable for arm body cylindrical tubes (carbon fiber, wall thickness 3mm) with an outer diameter of φ35mm. Its ring specifications are outer diameter φ40mm, wall thickness 2mm (inner diameter φ36mm), and axial length 20mm. The remaining structure, materials, and connection methods are the same as those of the proximal anti-torsion ring assembly.

[0229] The anti-torsion ring is a non-main load-bearing component. It works in conjunction with the connecting wall plate at the end to limit the relative displacement of the three circular tubes when subjected to torsion, thereby improving the overall torsional stiffness of the robotic arm. It can also prevent the reduction of bending stiffness to a certain extent, making the overall arm closer to the theoretical value.

[0230] 2. End protection pipe

[0231] The robotic arm described in Example 1 is equipped with an inner and outer protective tube structure for connecting the end of the arm body to the wall panel. The parameters of the protective tube are adjusted accordingly depending on the material of the arm body (aluminum alloy / carbon fiber).

[0232] (1) Aluminum alloy arm section protective tube (suitable for aluminum alloy round tubes with outer diameter φ40mm, wall thickness 3mm, and inner diameter φ34mm)

[0233] Inner protective tube: Made of 7075-T6 aluminum alloy, with specifications of outer diameter φ33mm, wall thickness 3mm (inner diameter φ27mm), and length 50mm. Its insertion length into the inner hole of the arm body's circular tube is 40mm. A silicone rubber gasket with a total thickness of 1mm after assembly is installed between the inner protective tube and the arm body's circular tube, achieving an elastic connection through an interference fit (interference amount 0.2-0.3mm). The exposed 10mm length of the inner protective tube is machined with external threads for connection to the threaded holes on the inner sidewall plate.

[0234] The outer protective tube is made of 7075-T6 aluminum alloy, with specifications of an outer diameter of φ47mm, a wall thickness of 3mm (inner diameter φ41mm), and a length of 50mm. It has a flange at the end with an outer diameter of φ53mm and a thickness of 3mm, and four evenly distributed connection holes. The outer protective tube is fitted over the outer wall of the arm body's circular tube, and a 1mm thick silicone rubber gasket is placed between it and the outer wall of the arm body's circular tube. An interference fit (0.2-0.3mm) is used to achieve a flexible connection. The flange is fixed to the outer wall panel with screws.

[0235] (2) Carbon fiber arm section protective tube (suitable for carbon fiber round tubes with an outer diameter of φ35mm, a wall thickness of 3mm, and an inner diameter of φ29mm)

[0236] Inner wall protective tube: The structure is the same as the aluminum alloy section, but the size is adjusted to an outer diameter of φ28mm, a wall thickness of 3mm (inner diameter of φ22mm), a length of 50mm, an insertion depth of 40mm, and 10mm of exposed thread.

[0237] Outer wall protective pipe: The structure is the same as the aluminum alloy section, but the dimensions are adjusted to an outer diameter of φ42mm, a wall thickness of 3mm (inner diameter of φ36mm), a length of 50mm, and a flange outer diameter of φ48mm and a thickness of 3mm.

[0238] Rubber gaskets are provided between the inner and outer wall protective tubes and the arm body round tube. The rubber gaskets are preferably made of silicone rubber or EPDM, with a hardness of Shore A 70-80, a thickness of 1mm, and an interference fit of 0.2-0.3mm.

[0239] The aforementioned inner and outer protective tube structure, in conjunction with the inner and outer wall panels at the end of the robotic arm, forms a rigid-flexible coupling fixation method of "double wall panel clamping + elastic connection with rubber pads." Its beneficial effects are:

[0240] (1) By reinforcing the end of the boom tube with inner and outer protective tubes, the thin-walled tube is prevented from being crushed under long-term heavy load operation;

[0241] (2) The elastic deformation of the rubber gasket can absorb the asynchronous displacement of the three round tubes when they are under stress, relieve stress concentration at the connection, and improve fatigue life.

[0242] (3) This connection method has both rigid fixing and elastic buffering characteristics, and is easy to disassemble and maintain. When the rubber gasket ages, it can be replaced separately.

[0243] 3. Mechanical locking mechanism

[0244] The mechanical locking mechanism adopts an electromagnetically controlled axial telescopic end face toothed disc meshing structure, which mainly includes an annular toothed disc, an electric telescopic drive assembly, and a moving toothed disc.

[0245] The annular toothed disc is made of 45 steel with surface hardening treatment, a thickness of 2.5mm, an outer diameter of φ75mm, and an inner diameter of φ55mm. The tooth grooves are distributed on the end face of the ring, adopting the industrial common end face toothed disc structure. The tooth is set with equal tooth pitch circular arc teeth based on the middle diameter of φ65mm. The tooth shape is a 30° isosceles triangular straight tooth with a tooth depth of 0.8mm and a tooth width of 2mm. The annular toothed disc is fixedly installed on the inside of the lug mounting frame by screws.

[0246] The moving gear drive assembly adopts an electromagnetic drive telescopic structure with a rated axial travel of 2mm. The moving gear is a φ20mm, 2.5mm thick No. 45 steel disc, and its end face tooth profile is a perfect mirror match with the tooth profile, tooth pitch, and tooth direction of the annular toothed disc. During assembly, the center of the moving gear is aligned with the middle diameter area of ​​the annular toothed disc to ensure reliable tooth meshing without jamming.

[0247] In this embodiment, each joint preferably has two locking mechanisms arranged symmetrically on the left and right sides to ensure balanced force distribution.

[0248] 4. End-of-line adapter assembly

[0249] This structure serves as the end clamping and fastening structure for the load-bearing rods of the robotic arm, and also as the mounting location for the joint drive motor, locking mechanism, etc. For Embodiment 1 of the present invention, a double-walled clamping rigid rod in a H-shaped frame structure is preferred, reinforced with nylon material, preferably 20% glass fiber reinforced nylon GF20 with a density of 1.28 g / cm³. The end adapter assembly is a frame with a square end face, an outer frame side length of 140 mm and a wall thickness of 4 mm, a front wall thickness of 10 mm for the H-shaped double-walled plates, a middle wall thickness of 4 mm, a preferred distance of 30 mm between the two walls, and a mounting ear protrusion height of 100 mm. The two end adapter assemblies of each arm segment are identical except for the mounting ears. Therefore, the weights of the mounting frame with and without ears are calculated as 0.41 kg and 0.59 kg respectively, totaling 1 kg. This weight is greater than that in Embodiment 1, but it does not affect the overall logic that the total weight of the robotic arm is over 10 kg, which is still manageable by a small agricultural vehicle.

[0250] It is preferable to add reinforcing ribs near the joint torque motor and mounting ears to enhance the local structural strength and adapt to the joint torque. This optimization is a standard design and can be further optimized by industry professionals based on their experience.

[0251] Based on the strength requirements of the end effector assembly for the load at the end of the robotic arm, its configuration and materials can be optimized by industry professionals based on their experience. Materials can be replaced with high-strength metals such as aluminum alloy, titanium alloy, and steel, and different clamping solutions such as thickened single-wall plates, multiple-wall plates (at least two), and flanges can be used. The connection method with the rigid rods can be bolted, welded, or integrally formed. Standardized bolt connections are preferred between the rigid rods and the end effector assembly. A single arm section can be disassembled into independent rods, end effector assemblies, anti-torsion rings, and other parts for bulk transportation. In outdoor orchards and industrial sites, assembly can be completed simply by tightening bolts with a torque wrench, with a single arm section assembly time of no more than 10 minutes, adapting to the on-site assembly needs of remote locations. Components can be replaced individually after wear or damage, eliminating the need to scrap the entire arm section and significantly reducing maintenance costs.

[0252] Example 5:

[0253] A quantitative comparison of the performance of the three-tube truss configuration with that of the traditional single-tube arm.

[0254] This embodiment focuses on a 1m single-section boom, comparing the weight, rigidity (moment of inertia), and deflection requirements of the three-tube truss structure of this invention with those of a traditional single-tube boom, thus verifying the core performance advantages of this invention.

[0255] 1. Core Calculation Formula

[0256] Formula for moment of inertia of a single tube section: , where D is the outer diameter of the pipe and t is the wall thickness of the pipe;

[0257] (1) Moment of inertia of equivalent cross section of three tubes (parallel axis theorem): ,in It is the moment of inertia of the i-th single tube itself. It is the perpendicular distance from the centroid of the i-th single-tube section to the centroid of the composite section (equilateral triangle layout, where a is the side length of the triangle). It is the cross-sectional area of ​​the i-th single tube, and n is the total number of single tubes in the layout;

[0258] (2) Formula for deflection at the end of a cantilever beam: Where F is the concentrated load at the end, L is the arm span, E is the elastic modulus of the material, and I is the moment of inertia of the section (for a single tube). Three-tube extraction ).

[0259] 2. Standardize the comparison benchmark

[0260] All arm segments are 1m long, and all four segments are made of 7075-T6 aluminum alloy (elastic modulus E=72GPa, density 2.81g / cm3). The end-effector load is uniformly 1.5kg (14.7N). This study compares the core performance of the three-tube configuration (φ40×3mm, triangle side length 80mm) of this invention with that of a conventional single-tube arm in the industry. This calculation comparison only considers the end-effector deflection performance of the pure arm structure, ignoring non-critical components and weights such as the fixed parts at both ends of the robotic arm and the joint motors that have little impact on deflection; all arms are considered as equivalent to a 4m cantilever beam.

[0261] 3. The core comparison results are shown in Table 4.

[0262] (1) Calculation of deflection of equivalent section of three-tube layout:

[0263] The height of the triangle in the three-tube spatial layout Substitute the numerical values ​​of the vertices to calculate the centroid distance. Bottom corner point ;

[0264] Three-tube layout, single-tube moment of inertia ;

[0265] Area of ​​a single tube in a three-tube layout:

[0266]

[0267] Three-tube deflection:

[0268]

[0269] (2) Traditional single tube

[0270] Moment of inertia of φ60 tube cross section ;

[0271] Moment of inertia of φ80 tube section ;

[0272] φ60 pipe deflection:

[0273]

[0274] φ80 pipe deflection:

[0275]

[0276] The arm-shaped parameters of this invention are compared with those of a traditional single-tube design as follows:

[0277]

[0278] Table 4

[0279] 4. Conclusion

[0280] The three-tube truss structure of this invention, with a weight increase of only 25.4% compared to a φ60 single tube (1.2 times the weight), exhibits a significant reduction in end deflection, while increasing bending stiffness by 3.9 times (i.e., a 2.9-fold increase). In contrast, a φ80 single-tube arm, with a weight increase of nearly 1.3 times that of this invention, still exhibits a deflection that is 1.3 times that of this invention. Furthermore, single-tube arm engineering requires additional materials such as reinforcing ribs and joints to maintain the long-arm extension configuration, resulting in an actual weight far exceeding the calculated value for a pure single tube. This invention, aside from a slight increase in weight due to the torsional ring, requires no further weight increase, simplifying engineering implementation. The key to the aforementioned improvement lies in the side length 'a' of the three-tube equilateral triangle layout. This parameter acts as a rigidity "amplifier." By optimizing and increasing the length of 'a', the moment of inertia of the cross section can increase quadratically without increasing the weight of the arm's tube wall. This fundamentally solves the vicious cycle of "thickening and thickening inevitably increases weight" in traditional single-tube arms. It also breaks the vicious cycle of "achieving rigidity standards inevitably increases weight, and lightweighting inevitably reduces rigidity" in traditional single-tube arms from a structural perspective. This lays the foundation for reducing joint torque and ensuring rigidity in robotic arms. This principle enhances rigidity nonlinearly through structural optimization, breaking the linear thinking that "rigidity must be achieved by piling up materials."

[0281] It should be noted that the above deflection calculation is based on a simplified model where the arm body is considered an ideal rigid-plastic connection and the joint is locked, making it a completely rigid body. The aim is to compare the theoretical stiffness limits of different configurations under the same conditions. The actual end-effector deflection needs to be superimposed with the elastic deformation of the joint transmission system and locking mechanism. Its magnitude can be further calibrated through finite element simulation or prototype measurement, and it can generally reach several times the theoretical limit value.

[0282] Example 6:

[0283] Implementation example of adapting heavy-duty vehicles to standardized orchards.

[0284] This embodiment is designed for a standardized orchard large-scale harvesting scenario to verify the adaptability of the core configuration of the present invention to a heavy-duty harvesting vehicle platform.

[0285] Core Design: Reuses the 4m long boom core configuration of Example 1. The auxiliary column and gimbal are directly fixed to the protruding platform extending from the side wall of the heavy-duty vehicle by adding flanges at the bottom and bolting. The total weight of a single robotic arm system can be controlled to ≤25kg (excluding the two square tubes at the bottom in Example 1, which weigh 8.1kg). It can be installed on both sides of the vehicle to carry out large-area harvesting operations.

[0286] Large agricultural vehicles typically used for harvesting or transportation have a load capacity of one ton, with one set installed on each side, and a total weight ≤50kg, which is sufficient to bear the load without the risk of tipping over. Assuming a 2m height of the truck bed, the robotic arm is installed at approximately a 1m height. The robotic arm can be folded backward via its joints. Figure 10 As shown, after folding back, the fruit can be placed directly from the top of the carriage or from a certain lateral offset opening, simplifying the operation path.

[0287] Operational advantages: The robotic arm can achieve integrated picking and placing of fruit. After picking, it can directly fold back and place the fruit over the side wall of the truck bed, eliminating the need for an intermediate conveyor structure. The action of placing the fruit into the truck bed after picking is as follows: Figure 10 As shown; due to the large reach of the robotic arm, it can harvest fruits from multiple directions and heights, including the side, front, and back of the vehicle.

[0288] Example 7:

[0289] Short-arm scenario adaptation examples

[0290] This embodiment is designed for harvesting dwarf crops such as grapes, strawberries, and tomatoes, to verify the adaptability of the short-arm configuration of the present invention and expand the application boundaries of the solution.

[0291] Key parameters: The preferred total boom span is 1.6m, divided into 4 sections × 0.4m boom body, each section adopts a 3-tube equilateral triangle layout (tube spacing 50mm); end load 0.3kg (grape bunch) + actuator 0.1kg, calculated using the torque and weight formulas mentioned above.

[0292] Joint definition: J1-J4 are exactly the same as in Example 1. The robotic arm is a scaled-down structure of Example 1 with the same configuration. A simplified schematic diagram is shown below. Figure 11 As shown.

[0293] Torque calculation: The fully flattened posture is the extreme working condition. The basic torque = Σ (weight of a single component × lever arm from the center of gravity of the component to the joint), and the redundant torque = basic torque × 1.2 (including a 20% safety factor redundancy). The torque calculation formula is exactly the same as in Example 1.

[0294] Lever arm reference: The center of gravity of each arm section is at the midpoint of the section. The weight of the motor is distributed on one side of the arm section at the far end of the corresponding joint. The unit of lever arm is m, and the unit of torque is kgf·cm.

[0295] The joint torque requirements of the full carbon fiber tube and the full aluminum alloy tube arm bodies were compared respectively, and the results are shown in Table 5.

[0296]

[0297] Table 5

[0298] The comparison above shows that, after the robotic arm is shortened, the joint J1, which has the highest torque requirement, requires a redundant torque of 398.88 kgf·cm for an all-aluminum robotic arm. Using a worm gear motor of the same specifications as in Example 1, which weighs between 1.2 and 1.3 kg, has a rated load of 400 kgf·cm, and is only a few tens of centimeters in length, with various models available, it can drive the segment with the highest torque. For the all-carbon fiber robotic arm, the torque requirement is well within the 300 kgf·cm torque range of existing miniaturized torque motors, which meets the requirements.

[0299] The above data demonstrates that the robotic arm configuration of this invention, for short-arm applications (compared to the long arm length of Embodiment 1 of this patent), achieves light-load operation solely through the advantage of weight reduction, eliminating the need for oblique pulling assistance. The robotic arm can perform light-load operations using its own joint motors. The core configuration of this invention can seamlessly adapt to short-arm, light-load scenarios, providing stable drive without oblique pulling assistance. It combines the advantages of lightweight, low cost, and high stability, covering diverse harvesting needs such as dwarf crops and greenhouses; and can be further extended to industrial applications.

[0300] The 1.6m short boom structure parameters were used to verify its anti-rollover stability when installed on an agricultural tricycle. Referring to Example 2, two comparison conditions were established: an agricultural tricycle with a self-weight of 80kg, no additional counterweight, and a truck bed width of 1.2m and 1.5m. The calculation process was exactly the same as in Example 2 (the weights in the table below omit the weight of the mounting bracket and the motor of joint J1; lighter weight is less conducive to anti-rollover performance). The comparison results are shown in Table 6.

[0301]

[0302] Table 6

[0303] By comparing the static stability coefficients, it can be seen that the short boom configuration of the heaviest aluminum alloy boom fully meets the requirements for rollover resistance when used in small agricultural vehicles, with sufficient safety margin.

[0304] Compared to the 4m long-arm solution, the short-arm solution in this embodiment can achieve "stable operation of the bare vehicle" without additional counterweight, making it more accessible. With a 1m height in the truck bed, the robotic arm can move within a 1.2-1.6m wide truck bed span, with an equivalent maximum reach of 2.4m. This can cover part of the long-arm operation space, balancing low cost and practicality, and is suitable for the harvesting needs of most fruits (such as Fuji apples and grape bunches).

[0305] Example 8:

[0306] Implementation example of a short-arm, densely packed large-scale picking vehicle.

[0307] This embodiment is designed for large-scale, high-efficiency harvesting in standardized, wide-row-spacing orchards. Based on the core truss structure of this invention, it adopts a short-arm dense layout to optimize the harvesting operation logic and improve the efficiency of large-scale harvesting.

[0308] 1. Core Design: Reuses the 1.6m short-arm truss structure (4-section arm, 0.4m per section) of Embodiment 7 of this invention, with a total weight of ≤3.36kg for a single arm. The mounting base of the robotic arm with a 360° rotating gimbal is directly installed near the outer wall of the carriage, which is higher than the top edge of the fruit box / basket. The carriage serves only as a pure load-bearing container, without any lifting, transmission, or arm retraction avoidance mechanisms. It only holds standard fruit baskets. For example, if the overall height of the carriage is 1m, the carriage holds fruit baskets or boxes containing picked fruits. Multiple short arms are arranged at 1m intervals and symmetrically installed on the prefabricated mounting flanges on the upper surface of the carriage. The robotic arm is installed at a height of 1.2m, and the base of the robotic arm is 0.2m higher than the carriage, forming a "centipede-like" densely packed working layout. Ten sets of arms can be symmetrically installed in a 5m long carriage.

[0309] 2. Operational Logic: Each robotic arm corresponds to a fixed working area within the fruit tree canopy. The robotic arm performs unloaded lifting operations. The lightweight frame of the arm itself has no heavy load, significantly reducing motor output torque and overall energy consumption. After harvesting, the robotic arm rotates 180° or other appropriate angles under load, and the end effector naturally lowers, with the lever arm shortening synchronously. The rotation under load is physically labor-saving, greatly reducing joint load and structural stress. During this process, the end effector remains at least 0.2m above the truck bed height, preventing it from touching the truck bed walls. Once the robotic arm has rotated to its designated position, it directly places the fruit into the fruit basket or box below the truck bed. There is no need for arm folding (large-angle swing arm folding back and forth), no need for additional lifting compensation, and no need for a matching conveyor belt. The movement path is the shortest and the posture is optimal. The vehicle moves a certain distance, pauses, and multiple robotic arms work simultaneously and continuously. After harvesting one area, it moves to the next distance, repeating this process.

[0310] 3. Adaptability advantages: This embodiment does not require special design of picking vehicles and complex auxiliary mechanisms, such as lifting platforms and conveying systems. It only uses the existing heavy-duty picking vehicle chassis, which greatly simplifies the vehicle design. The operating efficiency can be increased as needed by densely deploying a number of robotic arms, which can significantly reduce the equipment threshold and operating costs for large-scale picking.

[0311] This embodiment is also applicable to the long-arm mode of embodiment six. The picking cart body is lowered to below the height of the robotic arm mounting base. In the long-arm mode, there is no need to fold the arm in the opposite direction. The fruit placement action can be completed by simply rotating the arm. The action path is shorter and the efficiency is higher. Its working logic is completely consistent with that of the short-arm rotating fruit placement.

[0312] Example 9:

[0313] Examples of short-arm shallow water underwater applications

[0314] This embodiment is based on the 1.6m short-arm three-tube configuration of Embodiment 6, and verifies the scalability of the present invention in shallow water underwater operation scenarios.

[0315] 1. Core Modification Plan

[0316] Drive component replacement: Replace the conventional joint motor with an IP68 waterproof servo motor (or a dedicated underwater sealed motor) to ensure sealing reliability in shallow water environments; or replace it with a hydraulic motor drive system, including a hydraulic motor, hydraulic power source, and control valve assembly. The hydraulic motor directly replaces the conventional joint motor, driving the joint rotation through the rotation of the hydraulic motor. The drive logic is completely consistent with that of the joint motor, with only the power source being replaced by a hydraulic system.

[0317] Buoyancy balance design: The thin-walled tube of the robotic arm adopts a front-to-back through structure (to balance the water pressure inside and outside the tube and avoid pressure deformation). The outer side of the arm is covered with lightweight water pressure resistant foam (or lightweight floats are fixed near the joints) so that the positive buoyancy of the underwater arm body is basically offset by its own weight (leaving a slight gravity). The specific buoyancy compensation material can be selected by those skilled in the art as needed.

[0318] End effector adaptation: Connect underwater actuators (such as existing mature two-claw grippers) via flanges to meet the grasping needs of shallow-water organisms such as sea cucumbers and abalone.

[0319] 2. Installation and Application Scenarios

[0320] Platform: Can be directly integrated into the flange face of AUV and ROV, or the side / bottom mounting flange of small boats (the gimbal is fixed to the flange face).

[0321] Operating depth: Suitable for shallow water operations of 3-5m, or water surface platforms that can accommodate water depths of 1-2m, meeting the needs of pond aquaculture and shallow water fishing in the wild.

[0322] 3. Technical Principles and Advantages

[0323] Simplified torque: Buoyancy offsets more than 90% of the arm's weight, eliminating the torque explosion problem. The joint motor only needs to focus on precise angle control and resisting the reaction force of water flow. Existing small waterproof high-torque servo motors can be directly adapted.

[0324] The structure remains unchanged: the three-tube configuration of the arm and the control method are completely consistent with the land scenario, requiring no inclined cable assistance, resulting in low modification costs and strong scalability;

[0325] Advantages of this solution: Compared to traditional pipe suction fishing, this solution can use multiple arms in close proximity, with minimal disturbance to the water body, greater operational flexibility, and the fine tube truss structure can minimize the impact of water flow on the accuracy of the arms, making it suitable for batch capture and harvesting of shallow water organisms.

[0326] 4. Conclusion

[0327] This embodiment achieves the migration of the three-barreled boom from land to shallow underwater scenarios through a simplified modification of "waterproof component replacement + buoyancy balancing." While the core technical solution remains essentially unchanged, it expands the application boundaries of the patent. Because the boom in this configuration adopts a fully continuous hollow structure, the internal and external water pressure are balanced in real time. The boom itself is not limited by water depth; as long as the joint drive components (such as hydraulic motors or hydraulic rods) have the corresponding pressure resistance, this boom type can operate stably at any depth. This 'load-bearing-drive' separation architecture allows the boom and drive system to be optimized and replaced independently, greatly improving the reliability and maintainability of deep-sea operations. The boom modification requires no complex R&D and can be implemented using existing mature components, demonstrating significant technical advantages and industrialization potential in scenarios such as shallow-water biological harvesting, underwater light operations, and deep-sea operations.

[0328] Example 10:

[0329] Dual robotic arm collaborative operation adaptation example

[0330] This embodiment is based on the core configuration of the present invention and constructs a dual control mode of "coarse adjustment of the main arm + fine adjustment of the secondary arm" to adapt to the precise harvesting or operation needs of complex canopies.

[0331] 1. Main robotic arm (lifting platform foundation)

[0332] The 4m three-tube boom configuration of Example 1 is adopted: 4 sections × 1m, 7075 aluminum alloy φ40×3mm at the near end, 3K carbon fiber φ35×3mm at the far end, and three tubes in an equilateral triangle layout (80mm spacing).

[0333] Core function: Performs "coarse positioning" - Through multi-joint coordination and diagonal tension reduction, it can achieve lifting, translation, and tilting (0-90°) within a range of 4m. After reaching the position, the locking mechanism locks all joints to form a rigid lifting platform.

[0334] End interface: The original auxiliary flange is retained, and a small pan-tilt unit (weighing ≤0.5kg, supporting 0-360° horizontal rotation) is added to connect the auxiliary arm.

[0335] 2. Secondary robotic arm (precision work unit)

[0336] Configuration design: Single-tube lightweight short boom, 2 sections × 0.2m, total boom span 0.4m, tubing material is φ18×1.2mm 3K carbon fiber tubing (single section weight ≤0.065kg, total weight of 2 sections ≤0.13kg).

[0337] Drive configuration: The two joints are equipped with small servo motors (rated torques of 20 and 35 kgf·cm respectively, single unit weight ≤0.07 kg, total weight of 2 units ≤0.14 kg), no need for diagonal pull (the short arm has a small load, and the motor's own torque fully meets the drive requirements).

[0338] End effector: Compatible with small bionic grippers (weight ≤0.1kg, gripping force 0.1-0.5kg) or miniature pruners for precise gripping and cutting in narrow spaces.

[0339] The total weight does not exceed 0.37kg.

[0340] 3. Dual-control collaborative logic

[0341] Main boom priority: The main boom is first adjusted to the target working area (such as the outer side of the canopy of tall fruit trees) through the coordination of the inclined pull and the joint motor. The locking mechanism locks all joints to ensure the rigidity of the platform.

[0342] Sub-arm fine-tuning: Based on the fixed posture of the main arm after locking, the sub-arm can flexibly adjust its angle within a radius of 0.4m to cope with narrow spaces that the main arm cannot directly reach, such as inside the canopy and dense branches, and complete fine operations such as picking and pruning;

[0343] Interlocking protection: When the main boom is not locked, the auxiliary boom cannot be started; when the auxiliary boom is in operation, the main boom joint motor and the inclined pull motor remain in low power standby mode. If the main boom's posture deviates (such as touching a branch), the locking mechanism unlocks, the main boom quickly fine-tunes and resets, and then locks again to ensure operational safety.

[0344] 4. Application Scenarios and Core Advantages

[0345] Precision fruit picking in orchards: The main arm is raised to a height of 3-4 meters above the outer edge of the canopy, while the secondary arm extends deep into the canopy to grab fruit, avoiding dense branches and reducing branch damage; High-altitude pruning: The main arm is adjusted to the target branch area, and the secondary arm is equipped with a pruning tool to precisely prune diseased and overly dense branches without the need for manual climbing; Multi-scenario expansion: It can be adapted to greenhouses, seedling bases, etc. The main arm is responsible for large-scale movement, while the secondary arm is responsible for fine operations in small spaces, balancing efficiency and precision.

[0346] Through this embodiment, the working range of the robotic arm is precisely expanded. With a main arm span of 4m and a secondary arm span of 0.4m, the equivalent working radius reaches 4.4m. The secondary arm can rotate 360°, covering the entire space around the end of the main arm, making up for the shortcomings of narrow-area operation. The secondary arm only requires the addition of a lightweight single-tube arm and a micro servo motor, without modifying the core structure of the main arm. The total added weight is ≤0.87kg, resulting in low modification costs and no impact on the anti-tipping performance of the main arm. The operation threshold is low: the main and secondary arms have clear division of labor, requiring no complex linkage algorithms. Ordinary farmers can operate it after simple training, making it suitable for non-standardized operation scenarios.

[0347] Example 11:

[0348] Examples of ultra-long arm splicing space applications

[0349] In the microgravity environment of space, the self-weight of the robotic arm generates almost no additional bending moment. Connecting multiple arm sections can significantly extend the reach without the need for guy ropes. For mainstream 10m-class robotic arms in aerospace, based on the core configuration of this invention (three-bar triangular closed-loop truss + anti-torsion ring + double-wall panel splicing), under the premise of a basically consistent launch outer contour envelope, parameter optimization can achieve stiffness close to or even exceeding that of existing box girders, while significantly reducing weight. It also possesses modular, loose-launch and on-orbit reconfiguration capabilities, verifying the scalability of this invention in space environments. For comparison under equivalent conditions, only the main load-bearing box girder segment of a single arm in an existing aerospace robotic arm was replaced with the core configuration of this invention; other structures retained the original structure and design of existing aerospace robotic arms, requiring minimal modification to conform to the configuration design of this invention.

[0350] Core Prerequisites and Benchmarks

[0351] Uniform material: All are made of aerospace-grade 7075-T7351 aluminum alloy, with an elastic modulus E=72GPa and a density ρ=2.81g / cm³;

[0352] Contour envelope definition: The diameter of the circumscribed circle of the truss is equal to the maximum cross-sectional height of the original box girder, ensuring that the space occupied within the rocket fairing is basically the same during launch, without the need to change any interfaces.

[0353] 1. Comparable to a 10-meter-class robotic arm

[0354] The existing baseline parameters for the box girder robotic arm are as follows:

[0355] Single arm length: 1.5m, total arm length of 6 tandem arms: 9m (total length including joints: 10.2m)

[0356] Box girder cross-section: 240mm × 320mm, wall thickness 4mm, maximum profile height 320mm

[0357] Single arm weight: 38kg; total weight of 6 arms: 228kg

[0358] Moment of inertia of the main section (stiffness core): 4.2 × 10⁻ 5 m 4 (Calculated based on equivalent values, with the long side direction being the stiffness core).

[0359] Box girder weight calculation: General formula for calculating the weight per meter of square / rectangular tube: .

[0360] In the formula: a is the length of the long side of the cross section (mm), b is the length of the short side of the cross section (mm, for square tubes a=b), t is the wall thickness of the tube (mm), and ρ is the density of the tube (g / cm³).

[0361] W= [2×(240+320)-4×4] ×4×2.81×10⁻³=12.41kg / m

[0362] Each section of the boom is 1.5m long, and the theoretical weight of a single box girder section is: 12.41 × 1.5 = 18.62 kg.

[0363] It should be noted that the actual box girder also includes internal stiffening plates, joints, etc. In engineering experience, the weight of such structural components accounts for about 50%-100% or even higher of the main girder. According to the design of a typical aerospace box girder, the total weight of a single section arm is 38kg, of which the main girder weighs about 18-20kg, and the auxiliary structures such as stiffening plates, joints, and flanges weigh about 18-20kg. This distribution is in line with the actual engineering situation.

[0364] Calculation of moment of inertia of box girder section in principal direction:

[0365] Formula for moment of inertia of rectangular section: .

[0366] Where: h is the length of the long side of the cross-section (mm), b is the width of the short side of the cross-section (mm), and t is the thickness of the cross-section (mm);

[0367] Substituting h=320mm, b=240mm, t=4mm, then:

[0368]

[0369] It should be noted that box girders are thin-walled structures, and internal stiffeners are necessary to ensure local stability. These stiffeners, located within the cross-section, contribute minimally to overall bending stiffness but significantly increase weight. To balance the weight, the main wall panels are often made thinner, further reducing overall stiffness. Therefore, the effective moment of inertia of the box girder is far lower than the theoretical value (typically only 60%-80%, and in extreme cases less than 50%). This is an inherent contradiction in box girder system design and a long-standing technical challenge in the aerospace field. The design of this comparative project uses 4.2 × 10⁻⁶. -5 m 4 This value serves as a benchmark, and all subsequent comparisons will be based on it. The three-tube truss of this invention employs a completely different design philosophy: materials are arranged away from the centroid (with increased spacing), and local stability is ensured through anti-torsional rings, eliminating the need for internal stiffeners. Therefore, the truss stiffness can approach the theoretical value, effectively resolving the "stability-stiffness" contradiction in the box girder system.

[0370] 1.1 Basic Truss Replacement Solution (Isosceles Triangle Layout, Extreme Weight Reduction)

[0371] It uses three aerospace-grade 7075-T7351 aluminum alloy square tubes with a cross-section of 45×45m and a wall thickness of 4mm, arranged in an isosceles triangle.

[0372] Layout: Two tubes are positioned at the two base points of an isosceles triangle, located at the two vertices of the short side of the box girder section. One tube is positioned at the center of the other short side, serving as the vertex of the isosceles triangle. The outer wall of the square tube is completely flush with the outer wall of the box girder, and the outer envelope is completely consistent.

[0373] The isosceles triangle of the layout cross-section has a height H = 320 - 45 = 275 mm and a base length L = 240 - 45 = 195 mm.

[0374] Weight calculation:

[0375] Weight per meter of a single square tube: W = [2 × (45 + 45) - 4 × 4] × 4 × 2.81 × 10⁻³ = 1.843 kg / m.

[0376] The total weight of the three poles of a single boom (1.5m) is 1.843 × 1.5 × 3 = 8.29 kg.

[0377] The auxiliary structure (double wall panel + anti-torsion ring) is estimated to weigh 2.9 kg. For detailed design, please refer to Example 4.

[0378] Total weight of a single arm: 8.29 + 2.9 = 11.19 kg.

[0379] The principal moment of inertia of the cross section is calculated according to the parallel axis theorem:

[0380] The cross-sectional area of ​​a single square tube is A = 452 -(45-2×4) 2 =6.56×10 -4 m 2 .

[0381] Moment of inertia of a single square tube about its centroidal axis: H is the outer contour width (mm), and h is the inner hole width (mm).

[0382]

[0383] The centroid of the isosceles triangle lies on the midline of the three-tube configuration, a distance from the base. Place, therefore:

[0384] Distance from the two bottom tubes to the centroid of the assembly

[0385] Distance from vertex tube to the composite centroid

[0386] Contribution of the Parallel Axis Theorem:

[0387]

[0388] The sum of the moments of inertia of the three square tubes The moment of inertia of the composite section is much smaller than that of the parallel axis term and can be ignored. .

[0389] Unlike the "reinforcement and thinning" approach used in box girders, the three-tube truss of this invention employs an "outward expansion layout + anti-torsion ring" design: materials are arranged away from the centroid to obtain high stiffness, and local stability is ensured by the anti-torsion ring. This eliminates the need for internal stiffeners and the need to thin the main wall panels to balance the weight. Therefore, the actual stiffness of this invention can approach the theoretical design value, and the theoretical calculation value is directly used in the comparison.

[0390] The comparison results of the overall robotic arm parameters of the present invention and the original box girder arm are shown in Table 7:

[0391] Table 7

[0392] The above comparative calculations only compared the weight reduction and changes in the moment of inertia of the cross section caused by the change in the main box structure of the robotic arm. Under the premise of a significant weight reduction in the robotic arm of the comparison section, the moment of inertia of the cross section (equivalent to stiffness) was reduced to about 78.8% of the original structure.

[0393] 1.2 Truss Strengthening Scheme

[0394] Furthermore, based on the configuration and principle of this invention, the following methods can be used to increase the moment of inertia (i.e., stiffness) of the cross section, thereby meeting the requirement for enhanced overall stiffness:

[0395] (1) Enlarge the horizontal dimension of the top tube and change it to a rectangular tube with a length × height of 90 × 45 mm and a wall thickness of 4 mm. This is equivalent to two rectangular tubes with a cross section of 45 × 45 mm and a wall thickness of 4 mm placed side by side (one less wall thickness). The other two tubes remain unchanged, and the existing envelope can still be maintained.

[0396] The cross-sectional area A of the top pipe fitting t =90×45-82×37=1.016×10 -3 m 2 Moment of inertia I 0,t =(45×90 3 -37×82 3 ) / 12 = 1.0337 × 10 -6 m 4 Since the value is small, it can be ignored.

[0397] Weight per meter of a single top rectangular tube: W t =A t ×ρ=1.016×10 −3 ×2.81×10 3 =2.855 kg / m.

[0398] Single boom (1.5m) top tube weight: 1.5 W t =1.5×2.855=4.28 kg.

[0399] The cross-sectional area A of the two bottom rods b Still 6.56×10 -4 m 2 Moment of inertia =1.855×10 -7 m 4 The value is small and can be ignored.

[0400] The total weight of the two bottom square tubes in a 1.5m section is: 1.843 × 1.5 × 2 = 5.529 kg.

[0401] Static moment S=2×6.56×10 -4 ×0+0.275×1.016×10 -3 =0.2794×10 -3 m 3 .

[0402] New centroid height: Y c = S / (2A b + A t = 0.2794 × 10 -3 / (2×6.56×10 -4+1.016×10 -3 =0.12m.

[0403] Then the distance d from each tube to the centroid b =0.12m, d t =0.275-0.12=0.155m.

[0404] Then the moment of inertia of the combined section in the principal direction is:

[0405]

[0406] The moment of inertia of the main section in this reinforcement scheme can reach 4.33 × 10⁻ 5 m 4 The original box girder (4.2×10⁻) 5 m 4 The stiffness of the single-arm girder increased by 103.1% compared to the original box girder (38 kg), achieving a reversal. The weight of the single arm increased to 12.7 kg (5.529 + 4.28 + 2.9 kg), still a 66.6% reduction compared to the original box girder. This design, without expanding the envelope, significantly improved the moment of inertia in the principal directions by increasing the top material and prioritizing its placement away from the centroid (increasing the width of the transverse single tube cross-section and increasing the cross-sectional area). Compared to the uniform cross-section triangular tube design, the weight increase was approximately 1.5 kg (13%), but the stiffness increased from 79% to 103% (24%), while the overall weight remained significantly lower than the original box girder, demonstrating extremely high cost-effectiveness. These results verify the flexibility and efficiency of this invention's configuration in aerospace applications.

[0407] (2) Referring to method 1, other solutions include increasing the lateral length of only the two bottom tubes, or simultaneously expanding the lateral length of the top and bottom members. The different methods differ only in their material stacking tendency, resulting in different weight reduction effects, but all can achieve stiffness close to or even exceeding that of the original box girder while maintaining significant weight reduction. Those skilled in the art can calculate this based on the parallel axis theorem, which will not be elaborated here.

[0408] (3) Four square tube layout: Referring to the truss reinforcement scheme of Reference Method 1, the single tube at the top is replaced with two parallel square tubes (i.e., two at the bottom and two at the top), forming a rectangular four-corner layout. By adjusting the horizontal spacing between the two top tubes, the moment of inertia of the cross section in the non-principal direction can be further increased without significantly increasing the weight, thereby improving the omnidirectional stiffness. Those skilled in the art can derive its moment of inertia based on the parallel axis theorem and the aforementioned calculation examples, which will not be elaborated here.

[0409] 2. Modular assembly scheme for robotic arms, breaking the constraints of envelope contour.

[0410] For future robotic arms that may be 20m-30m or even longer, and while maintaining sufficient rigidity, the only approach for existing box-type solutions is to lengthen, thicken, and increase the size of the robotic arm. The arm needs to be assembled as a whole before transportation. Even if a single arm is transported separately, the length and weight of the arm are always limited by the size constraints and load-bearing capacity of the launch vehicle.

[0411] Based on this invention, the core of the robotic arm can be designed as a "modular splicing of a single rod and double wall panels". This means that the robotic arm can be disassembled into standardized single rods of different lengths, such as 1 meter or 2 meters, joint modules, serialized double wall panels, and anti-torsion rings, and then stacked into the rocket fairing. The rods and double wall panels are designed with standardized bolt / quick-fit interfaces. Astronauts can complete the assembly of the robotic arm by simply tightening bolts and inserting positioning pins, without any complicated welding or integrated molding processes.

[0412] Taking the isosceles triangular layout of a three-sided tube (single tube cross-section size 45×45mm, wall thickness 4mm) as an example, if H is increased from the current 275mm to 500mm, according to the parallel axis theorem, the moment of inertia of the composite section increases with H². Ignoring its own moment of inertia... The changes in moment of inertia under different H values ​​are shown in Table 8. The data in Table 8 have been calculated and verified according to the aforementioned formula:

[0413]

[0414] Table 8

[0415] Furthermore, increasing the spacing between all tubes of the robotic arm can not only improve the moment of inertia of the main force-bearing surface, but also simultaneously increase the length of the short side (i.e., increase the L-spacing), thereby improving the rigidity in the other direction and ensuring that the omnidirectional performance of the robotic arm is basically the same. While increasing the spacing between individual tubes, the moment of inertia in the main direction can be further and rapidly increased under the condition of limited weight increase, and the design and combination are flexible and controllable.

[0416] Based on the design of this scheme, from the perspective of the mechanical structure of the robotic arm, the limitations of the launch envelope size on the size, length, weight and stiffness of the robotic arm can be completely broken. Through modular splicing and on-orbit assembly, the size of the arm is only limited by the size of a single cargo compartment piece, while the length of a single piece can reach several meters, which is much larger than the envelope of the existing overall launch. The long arm only needs to design the height of the triangle (or the side length of the equilateral triangle) to be large enough to obtain stiffness and length far exceeding that of traditional box girders at a relatively small weight cost.

[0417] In summary, compared with existing integrated solutions, the modular splicing solution in this embodiment offers the following advantages:

[0418] (1) During launch, space can be utilized to the fullest extent: bulk stacking with zero waste: disassembled rods and modules can be stacked tightly like building blocks, without any cantilever dead zones, making full use of all available space inside the fairing;

[0419] (2) Hollow Reuse of Rods: Hollow thin-walled tubes are independent cavities. During launch, usable tools, scientific experimental payloads, small satellite parts, and even gas cylinders / small fuel tanks can be placed inside. The rods are both the load-bearing structure of the robotic arm and the transport container for the payload.

[0420] (3) Low cost of on-orbit maintenance, reconfiguration and upgrade: Existing aerospace robotic arms are single-arm segments. If a micro-crack or impact damage occurs in a segment, or if a section of thermal control / cable has a problem, the entire robotic arm may be scrapped and it is difficult to repair on-orbit. In contrast, with this solution, if a single link is damaged, only the faulty part needs to be removed and replaced with a new one, without having to touch the entire arm segment or the entire robotic arm.

[0421] (4) On-orbit free reconfiguration: The same set of rod modules can be assembled into a 20-meter ultra-long arm during the construction of the space station for large structure assembly; during routine maintenance, it can be disassembled into two 10-meter short arms for dual-machine collaborative operation; it can even be disassembled into multiple sets of small robotic arms, which can be installed in different modules of the space station, so that one module can achieve multiple uses.

[0422] (5) Minimize the risk of launch overload: Existing integrated long robotic arms are in a folded cantilever state during launch. The high-frequency vibration and impact overload of the rocket will generate huge dynamic stress on the arm body, which is prone to fatigue damage. Additional reinforcement structures must be made, which further increases the weight. In contrast, the bulk rods of this invention are tightly fixed in the fairing during launch. There is no cantilever structure, so the impact of launch overload is almost zero. No additional reinforcement is required, which can save a lot of weight.

[0423] (6) This scheme provides a feasible technical path for developing large space facilities in the absence of super-large rockets.

[0424] Example 12:

[0425] Implementation examples of vertical / lateral series layout adaptation.

[0426] This embodiment is designed for horizontal large-span operations such as industrial material handling and machine tool loading and unloading. It adopts a straight horizontal series layout, with the arm units connected in series in the horizontal direction. The total arm span is 4m. The core truss structure, end adapter components, and drive components are completely consistent with the first embodiment. Only the series rotation position plane of the arm units is adjusted. The mounting ears of the mounting frame with ears are changed from extending upwards to extending forward along the axial direction of the robotic arm tube. Through straight series connection, unobstructed large-span operations in the horizontal direction are achieved. Its lightweight and high rigidity technical effects are completely consistent with the first embodiment.

[0427] To address the needs of storage in narrow spaces and lateral operation, a lateral stacking and tandem layout can be adopted. This eliminates the need for extended mounting ears. The arm units are hinged sequentially along the lateral rotation plane, and when retracted, they are stacked parallel to each other laterally. This adapts to the storage and operation requirements of confined spaces, and the core structure and technical performance are completely consistent with Embodiment 1. A schematic diagram of the arm's extended structure is shown below. Figure 12 As shown.

[0428] Example 13:

[0429] Hydraulic linear drive heavy-duty industrial robotic arm.

[0430] This embodiment is based on the three-tube truss structure of Embodiment 1, replacing the joint drive motor with a hydraulic linear drive system. The hydraulic linear drive system includes a hydraulic cylinder, a hydraulic power source, and a control valve assembly. One end of the hydraulic cylinder is hinged to the end junction assembly of the preceding boom section, and the other end is hinged to the side wall of the following boom section. The joint rotation is driven by the extension and retraction of the hydraulic cylinder. This embodiment is particularly suitable for heavy-duty industrial scenarios, such as large workpiece handling and mining machinery. The hydraulic drive provides greater thrust and impact resistance, and combined with the lightweight structure of the three-tube truss, it enables efficient operation under heavy-duty conditions.

[0431] It should be noted that the principle of pneumatic linear drive is exactly the same as that of hydraulic drive. Only the drive system is replaced with a pneumatic cylinder, a pneumatic source, and a control valve group (pneumatic adapter). It can also be applied to the truss structure of this invention.

[0432] Additional notes:

[0433] The tube dimensions, wall thickness, triangle side lengths, motor parameters, etc., mentioned in the embodiments of this invention are preferred examples adapted to different application scenarios (including orchard picking, short-arm light-load operations, underwater operations, aerial operations, etc.), and are not limitations. Those skilled in the art can flexibly adjust the parameters according to actual needs. As long as the core technical solution of "rod + triangular / near-triangular structural layout + lightweight design" is not changed, and the core function of "lightweight and high rigidity" (which can be adapted to multiple application scenarios such as long-arm and short-arm) is not deviated from, it falls within the protection scope of this invention. Such parameter adjustments constitute equivalent substitution and do not affect the infringement determination.

[0434] The core technology of this invention lies in the increased stiffness inherent in the rigid frame structure formed by the multi-strut truss and the end-connecting assembly. The stay cable auxiliary system is only used to solve the driving problem in long-arm applications and is not the only solution. In scenarios with shorter arm spans, underwater buoyancy counteracting gravity, or microgravity environments in space, the stay cable auxiliary system can be omitted, and operation can be achieved solely through the three-tube truss structure and joint drive device. In these cases, significantly better stiffness and weight reduction than traditional single-tube booms can still be achieved. Those skilled in the art can choose whether to configure the stay cable auxiliary system based on actual working conditions; this choice does not affect the scope of protection of the core structure of this invention.

[0435] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if these modifications and modifications of the invention fall within the scope of the claims and their equivalents, the invention is also intended to include these modifications and modifications.

Claims

1. A robotic arm device, characterized in that, Includes multi-section boom units and drive components, among which, The multiple boom units are connected in series, and at least one boom unit is a multi-bar parallel truss rigid load-bearing frame. The rigid load-bearing frame is formed by multiple rigid members and end transition components. The projection points of the multiple rigid members on the plane perpendicular to the boom axis are distributed in a closed loop containing at least one triangle. The axial direction is a hollow structure that runs through the front and back. The rigid load-bearing frame is composed only of the rigid members and end transition components, which together constitute its entire load-bearing structure. The end adapter assembly is fixedly connected to the ends of the plurality of rigid rods, and the end adapter assembly is provided with a connection structure adapted to the plurality of rigid rods. The drive assembly includes a joint torque motor or a hydraulic / pneumatic drive structure or a combination thereof, used to drive the linkage of multiple boom units, and the drive assembly is assembled and connected to the end adapter assembly.

2. The robotic arm device according to claim 1, characterized in that, The rigid member is provided with at least one set of anti-torsion structures, which divide the single rigid member into equivalent short segments. The anti-torsion structures form at least one geometrically non-deformable structure by enclosure. The anti-torsion structure is any one or more combinations of the following: a combination structure of a ring structure and a rigid member, a cross-link structure, a frame structure, and a plate structure.

3. The robotic arm device according to claim 1, characterized in that, It also includes an inclined pull auxiliary drive structure, which includes a pull rope and a pull rope drive motor. One end of the pull rope is fixed to a preset pull rope fixing position of the arm unit, and the other end is connected to the winding mechanism of the pull rope drive motor.

4. The robotic arm device according to claim 1 or 3, characterized in that, It also includes an auxiliary mounting base, which is equipped with a rotating gimbal turntable. The robotic arm device and the inclined pull auxiliary drive structure are both mounted on the rotating gimbal turntable of the auxiliary mounting base.

5. The robotic arm device according to claim 4, characterized in that, The rigid members of the multiple sections of the boom unit adopt a differentiated material layout. The rigid members of the boom unit near the auxiliary installation base are made of high-strength metal, while the rigid members of the boom unit far from the auxiliary installation base are made of low-density, high-strength material.

6. The robotic arm device according to claim 1, characterized in that, The rigid members of the multi-bar parallel truss rigid load-bearing frame are rigid load-bearing profiles with closed or open cross sections, and can be any one or a combination of thin-walled tubes, thick-walled tubes, solid bars, coaxial nested composite tubes, channel profiles, and profiles with irregular cross sections; when the rigid member is a tubular or hollow profile, a crush-resistant protection structure is provided at the connection between it and the end transition assembly.

7. The robotic arm device according to claim 1, characterized in that, Non-load-bearing conventional auxiliary components can be installed within the rigid load-bearing frame.

8. The robotic arm device according to claim 1, characterized in that, The two adjacent arm units are hinged by a rotary joint. The joint torque motor and hydraulic / pneumatic drive structure are embedded in the rotary joint. A mechanical locking mechanism is also provided in the rotary joint.

9. The robotic arm device according to claim 1, characterized in that, The rigid rod is assembled with the end adapter and adjacent arm unit in a detachable connection structure.

10. The robotic arm device according to claim 1, characterized in that, The cross-section of the multi-bar parallel truss rigid load-bearing frame is formed by three rigid members enclosing an equilateral triangle layout.

11. A collaborative control method for a robotic arm device according to any one of claims 1 to 10, characterized in that, Includes the following steps: Step 1, Attitude Acquisition and Torque Calculation: The real-time attitude of each arm unit is acquired by using the rotation angle data of the joint torque motor, and the theoretical joint driving torque under the corresponding attitude is calculated. Step 2, end-point priority deployment control: When the arm extends from the retracted state, it will prioritize the extension of the end arm unit. The end arm unit will only complete the torsional control of the full swing angle range through the joint torque motor, without the need to start the inclined pull auxiliary drive system. Step 3, Multi-section arm coordinated deployment control: When deploying the remaining arm units, the torque margin of the joint torque motor is first determined based on the real-time posture. If the inclined pull auxiliary is required, the joint torque motor and the inclined pull drive motor work together. The inclined pull drive motor adjusts the pulling force in real time to offset part of the torque of the corresponding joint. The remaining torque is output by the joint torque motor to gradually complete the arm deployment. If the joint torque motor can be driven independently, the joint torque motor works alone, and the inclined pull drive motor only performs the rope winding and releasing actions to maintain the basic tension of the rope and prevent tangling. Step 4, Position Locking Control: After the boom extends to the working position, the mechanical locking mechanism is triggered to lock the corresponding joints, so that the multi-section boom unit forms a rigid whole; Step 5, end-effector priority retraction control: When the arm retracts, first unlock the mechanical locking mechanism of the corresponding joint. During the retraction process, prioritize shortening the lever arm corresponding to the maximum torque load, prioritize shortening the lever arm of the end-effector, pull the end-effector back from the working space to avoid obstacles, and simultaneously adjust the diagonal pulling force corresponding to each section of the arm to maintain rope tension, thus completing the arm retraction.

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