A continuum robot underactuated active-passive cooperative control device

Abstract

The application relates to the technical field of continuum robot control, in particular to a continuum robot underactuated active-passive cooperative control device. Two mechanical arms are connected in dislocation to form a two-section independent-motion continuum mechanical arm, each mechanical arm is provided with a plurality of sequentially homotopic connecting bending units, a pre-tightening compensation mechanism is circumferentially installed on a core body, an underactuated control mechanism is installed on a mounting disc, a first rope is connected with the mechanical arm and a fixed rope plate; one end of a second rope is connected with the mechanical arm, the other end sequentially passes through the mechanical arm, the pre-tightening compensation mechanism and a first positioning wheel assembly and is connected with the fixed rope plate to form a tension compensation loop for the first rope. The application adopts a two-section continuum structure design, realizes kinematics dimension reduction, can realize multi-direction bending capacity in a narrow space through bionics optimization, adopts a composite pre-tightening mechanism of a spring and a pulley, passively compensates rope deformation through an elastic element, and realizes dynamic tension maintenance.

Description

Technical Field

[0001] This invention relates to the field of continuous robot control technology, and in particular to an underactuated active-passive cooperative control device for a continuous robot. Background Technology

[0002] In fields such as industrial inspection, medical surgery, and disaster relief, traditional rigid robotic arms, limited by their fixed joint structure and limited degrees of freedom, struggle to meet the demands of precise operations in complex, unstructured environments. For example, in minimally invasive surgery, instruments must enter human cavities through narrow incisions to perform high-precision operations; in industrial pipeline inspection, equipment must maneuver flexibly and avoid obstacles within winding and confined spaces.

[0003] In recent years, continuum robots, through their rigid-flexible coupling structure and multi-degree-of-freedom cooperative actuation, have demonstrated outstanding environmental adaptability and motion dexterity, enabling them to work in narrow and extremely constrained environments. Compared with other existing types of continuum manipulators (rod-driven or fluid-driven), cable-driven continuum manipulators are more precise and can provide higher payload capacity.

[0004] In existing technologies, robots driven by flexible cables need to independently control the tension of each cable, which has the following drawbacks:

[0005] (a) During exercise, the rope may become loose in certain areas, which may have an adverse effect on the accuracy of the movement and the operability of the load;

[0006] (ii) The number of drive motors depends on the topology design of the rope drive system. Increasing the number of ropes will significantly increase the overall complexity of the system.

[0007] (iii) In terms of mechanical structure, a more complex pulley system needs to be arranged to cope with the tension of multiple ropes, and a precise tension distribution mechanism needs to be designed. At the control level, the parallel robot cooperative control of multiple motors will introduce nonlinear coupling problems, which will greatly increase the design difficulty of the control algorithm.

[0008] (iv) Regarding system reliability, a careful balance needs to be struck between redundant design and failure probability. These issues severely restrict the practical application breakthroughs of this type of robot in scenarios requiring high precision, high load, and high reliability, such as surgical navigation and industrial inspection. Summary of the Invention

[0009] This invention aims to at least improve one of the technical problems existing in the prior art. To this end, this invention proposes an underactuated active-passive cooperative control device for a continuum robot.

[0010] The technical solution of the present invention is as follows:

[0011] The frame body has a mounting plate and a pre-tightening housing. The mounting plate and the pre-tightening housing are connected by a slide rod. The surface of the mounting plate is provided with multiple sets of first positioning wheel assemblies. A core is installed inside the pre-tightening housing.

[0012] Two robotic arms, the two robotic arms having the same structure and being staggered to form a continuous robotic arm with independent movement of two segments, the continuous robotic arm being mounted on the core, each robotic arm having multiple bending units connected in sequence and in the same position, each bending unit having rope holes distributed in a 90° circumferential direction;

[0013] Multiple pre-tensioning compensation mechanisms, each circumferentially mounted on the core,

[0014] Multiple underactuated control mechanisms are mounted on the mounting plate, and each underactuated control mechanism includes:

[0015] The motor is mounted on the surface of the mounting plate;

[0016] The ball screw has one end passing through the mounting plate and connected to the motor output shaft, and the other end connected to the core.

[0017] A rope fixing plate is assembled on the slide rod and the ball screw. The ball screw can be driven to rotate by a motor to drive the rope fixing plate to move vertically. The rope fixing plate has a first mounting part and a second mounting part.

[0018] A first rope has one end connected to the robotic arm away from the core, and the other end passing through the robotic arm and connected to the first mounting part.

[0019] The second rope has one end connected to the robotic arm away from the core, and the other end passes through the robotic arm, the pre-tension compensation mechanism, and the first positioning wheel assembly in sequence before being connected to the second mounting part to form a tension compensation loop for the first rope.

[0020] In one possible technical solution, the continuous robotic arm further includes:

[0021] The base plate is mounted on the core.

[0022] The first and second robotic arms are both composed of multiple bending units with the same structure connected in series. Each bending unit in the first robotic arm is connected in series and then mounted on the base plate; each bending unit in the second robotic arm is connected in series and then mounted on the first robotic arm, so as to form a continuous robotic arm with two independent movements.

[0023] In one possible technical solution, the rope hole reference line located in the first section of the robotic arm bending unit is arranged with a 45° phase difference from the rope hole reference line located in the second section of the robotic arm bending unit, so as to achieve independent movement of the two sections through rope connection.

[0024] In one possible technical solution, the bending unit near the base disk further includes:

[0025] Two first pillars are aligned and installed on the base plate, and the first pillars are provided with corresponding pin holes;

[0026] A cross-shaped connector has a first pin and a second pin, wherein the first pin is connected to the first support column to achieve two degrees of freedom rotation of the cross-shaped connector;

[0027] Two second pillars are arranged adjacent to the first pillar, and the second pillars are connected to the second pin.

[0028] The unit disk is connected to the second support column, which is located away from the second pin, and is connected to the second support column via the cross shaft connector to achieve four-degree-of-freedom rotation of the unit disk.

[0029] Multiple unit springs, each unit spring is installed on the outside of the first pillar and / or the second pillar, and connected to the base plate and the unit plate.

[0030] In one possible technical solution, the core further comprises:

[0031] The cylinder has parallel slide rails spaced apart on its outer circumference, which are fixedly connected to the inner wall of the pre-tightened outer shell.

[0032] Two cover plates are respectively installed at both ends of the cylinder to form a sealed cavity. Each cover plate located in the sealed cavity has multiple sets of second positioning wheel assemblies on its surface, and each cover plate has a through hole for a rope to pass through.

[0033] In one possible technical solution, the pre-tightening compensation mechanism further includes:

[0034] A hollow sleeve is installed on the outer wall of the core body;

[0035] A helical spring is connected to the hollow sleeve;

[0036] A guide rod is connected to the helical spring located away from the hollow sleeve, and the guide rod is embedded inside the hollow sleeve;

[0037] The I-shaped sliding component has shoulders on both sides, with each shoulder located on the upper and lower sides of the slide rail of the core. Intermediate pulleys are provided on the upper and lower sides of the middle part of the I-shaped sliding component. When the shape of the rope changes due to external force, the position of the I-shaped sliding component is adjusted by a helical spring to achieve tension balance of the rope.

[0038] In one possible technical solution, the cylinder body further includes an upper cylinder body and a lower cylinder body connected by a key, wherein mounting holes are distributed around the connection between the upper cylinder body and the lower cylinder body for fixing and installing the hollow sleeve.

[0039] In one possible technical solution, the second positioning wheel assembly located on different cover plate surfaces is symmetrical about the cylinder, which is used to adjust the ropes entering and exiting the pre-tensioning compensation mechanism to be in the same vertical direction, thereby reducing the occurrence of rope tangling and bias at the pulley end.

[0040] In one possible technical solution, the cross-sections of the pre-tightening shell and the cylinder are both regular octagons, wherein each interior angle of the pre-tightening shell is opposite to the middle of the side of the cylinder, for mounting slide rails, so that when the intermediate pulley moves under load, its pressure is always in the normal direction of the side wall of the cylinder, reducing the bias pressure of the component force on each component, reducing wear and loss, and improving the service life and smoothness of the device.

[0041] In one possible technical solution, the number of the first rope, the second rope, and the pretensioning compensation mechanism are the same.

[0042] The underactuated active-passive cooperative control device for a continuum robot according to the present invention has the following advantages:

[0043] 1. It adopts a double-section continuous structure design, with each section having independent pitch and bending degrees of freedom, achieving a total of 4 degrees of freedom for agile movement. The double-section configuration maps 8 ropes into 4 degrees of freedom, achieving kinematic dimensionality reduction. This configuration is optimized through bionics, enabling multi-directional bending capabilities in confined spaces.

[0044] 2. An underactuated architecture with four motors coupled to drive eight ropes was adopted, and the complex key technical challenges of multi-dimensional control were solved through electromechanical collaborative control;

[0045] 3. A composite pretensioning mechanism combining springs and pulleys is adopted, which passively compensates for rope deformation through elastic elements to achieve dynamic tension maintenance, effectively solving the problem of decreased positioning accuracy caused by slack in traditional flexible cable drive systems;

[0046] 4. A bidirectional tension coordination control mechanism based on a ball screw is adopted, which intelligently couples the drive and preload functions into a single motion unit through integrated design. This mechanism uses a ball screw nut as the core drive unit, with innovative axial extensions at both ends forming tension adjustment interfaces. Specifically, the upper end of the fixed rope plate directly connects to a vertically arranged first rope, undertaking the active posture adjustment function; the lower end of the fixed rope plate guides the second rope vertically upward through a double fixed pulley mechanism, constructing a bidirectional symmetrical tension balance system. When the screw rotates and drives the nut to move linearly, the antagonistic movements of the upper and lower ropes can be realized simultaneously. While the first rope actively adjusts its length, the second rope achieves synchronous compensation through a composite preload mechanism combining pulley switching and spring-pulley combinations. This mechanical coupling method ensures dynamic tension balance.

[0047] This invention, through the symmetrical design of the ball bearing nut and the synergistic effect of the spring-pulley composite mechanism, retains the rapid response characteristics of mechanical compensation while also possessing the precise adjustment capabilities of electronic control, effectively solving the slack problem in traditional cable-driven systems. The overall modular architecture design ensures tension stability while significantly improving system energy efficiency and ease of maintenance. The key innovation of this design lies in integrating the drive and pretensioning functions into a single motion unit through intelligent mechanical coupling, achieving true mechatronic collaborative control. This invention effectively solves the key technical bottlenecks in cable-driven continuous robots regarding control complexity, tension maintenance, and system reliability, providing an innovative solution for applications with stringent precision and reliability requirements, such as medical robots.

[0048] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0049] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a schematic diagram of the structure of a continuum robot underactuated active-passive cooperative control device according to an embodiment of the present invention;

[0051] Figure 2 yes Figure 1 Enlarged schematic diagram of part A;

[0052] Figure 3 yes Figure 1 Enlarged schematic diagram of part B;

[0053] Figure 4 This is a schematic diagram of the cross shaft connector of the underactuated active-passive cooperative control device for a continuum robot according to an embodiment of the present invention;

[0054] Figure 5 This is a schematic diagram of the core installation of the underactuated active-passive cooperative control device for a continuum robot according to an embodiment of the present invention;

[0055] Figure 6 This is a schematic diagram of the core structure of the underactuated active-passive cooperative control device for a continuum robot with the top cover plate removed, according to an embodiment of the present invention.

[0056] Figure 7 yes Figure 6 Enlarged schematic diagram of part C;

[0057] Figure 8 This is a schematic diagram of the installation of the intermediate pulley in the underactuated active-passive cooperative control device for a continuum robot according to an embodiment of the present invention;

[0058] Figure 9 This is a schematic diagram of the active-passive cooperative control of an underactuated active-passive cooperative control device for a continuum robot according to an embodiment of the present invention.

[0059] Figure label:

[0060] The frame body 1, mounting plate 11, pre-tightening outer shell 12, core 13, cylinder 130, slide rail 1301, cover plate 131, second positioning wheel assembly 1310, slide rod 14, first positioning wheel assembly 110;

[0061] Base plate 20, first section robotic arm 21, second section robotic arm 22, first support column 210, cross shaft connector 211, first pin 2111, second pin 2112, second support column 212, unit plate 213, unit spring 214, snap ring cylindrical pin 215;

[0062] Hollow sleeve 31, helical spring 32, guide rod 33, I-shaped sliding component 34, intermediate pulley 341;

[0063] Motor 41, ball screw 42, rope fixing plate 43, first mounting part 431, second mounting part 432;

[0064] First rope 5;

[0065] Second rope 6. Detailed Implementation

[0066] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0067] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0068] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0069] The terms "first," "second," "third," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects and not to describe a particular order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, it may include a series of steps or units, or optionally, steps or units not listed, or other steps or units inherent to these processes, methods, products, or devices.

[0070] The accompanying drawings show only the portions relevant to this application, not all of them. Before discussing exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe operations (or steps) as sequential processes, many of these operations may be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations may be rearranged. The process may be terminated when its operation is completed, but may also have additional steps not included in the drawings. The process may correspond to a method, function, procedure, subroutine, subprogram, etc.

[0071] The terms “component,” “module,” “system,” “unit,” etc., used in this specification are used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. For example, a unit can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, a thread of execution, a program, and / or distributed between two or more computers. Furthermore, these units can be executed from various computer-readable media on which various data structures are stored. Units can communicate, for example, via local and / or remote processes based on signals having one or more data packets (e.g., data from a second unit interacting with another unit between a local system, a distributed system, and / or a network; for example, the Internet interacting with other systems via signals).

[0072] Example 1

[0073] like Figures 1 to 9 As shown, this embodiment provides an underactuated active-passive cooperative control device for a continuum robot, comprising:

[0074] The frame body 1 has a mounting plate 11 and a pre-tightening shell 12. The mounting plate 11 and the pre-tightening shell 12 are connected by a slide rod 14. The surface of the mounting plate 11 is provided with multiple sets of first positioning wheel assemblies 110. A core 13 is installed inside the pre-tightening shell 12.

[0075] Two robotic arms, the two robotic arms having the same structure and being staggered to form a continuous robotic arm with independent movement of two segments, the continuous robotic arm being mounted on the core 13, each robotic arm having multiple bending units connected in sequence and in the same position, each bending unit having rope holes distributed in a 90° circumferential direction;

[0076] Multiple pre-tensioning compensation mechanisms are mounted circumferentially on the core 13.

[0077] Multiple underactuated control mechanisms are mounted on the mounting plate 11, and each underactuated control mechanism includes:

[0078] Motor 41 is mounted on the surface of the mounting plate 11;

[0079] The ball screw 42 has one end passing through the mounting plate 11 and connected to the output shaft of the motor 41, and the other end connected to the core 13;

[0080] The rope fixing plate 43 is assembled on the slide rod 14 and the ball screw 42. The ball screw 42 can be driven to rotate by the motor 41 to drive the rope fixing plate 43 to move vertically. The rope fixing plate 43 has a first mounting part 431 and a second mounting part 432 for connecting ropes.

[0081] It should be noted that in this embodiment, when multiple rope fixing plates 43 are coplanar, there is a gap between adjacent rope fixing plates 43 to avoid interference during vertical displacement.

[0082] It should be noted that in this embodiment, the rope fixing plate 43 is provided with a ball nut, and the ball screw 42 passes through the ball nut and is connected to the rope fixing plate 43.

[0083] The first rope 5 has one end connected to the robotic arm away from the core 13, and the other end passes through the robotic arm and is connected to the first mounting part 431;

[0084] The second rope 6 has one end connected to the robotic arm away from the core 13, and the other end passes through the robotic arm, the pre-tension compensation mechanism, and the first positioning wheel assembly 110 in sequence before being connected to the second mounting part 432 to form a tension compensation loop for the first rope 5.

[0085] It should be noted that, in this embodiment, the continuous body robotic arm includes:

[0086] The base plate 20 is mounted on the core 13;

[0087] The first robotic arm 21 and the second robotic arm 22 are both composed of multiple bending units with the same structure connected in series. Each bending unit in the first robotic arm 21 is connected in series and then installed on the base plate 20; each bending unit in the second robotic arm 22 is connected in series and then installed on the first robotic arm 21, so as to form a continuous robotic arm with two independent movements.

[0088] It should be noted that, in this embodiment, the rope hole reference line located in the bending unit of the first section of the robotic arm 21 is arranged with a 45° phase difference from the rope hole reference line located in the bending unit of the second section of the robotic arm 22, so as to achieve independent movement of the two sections through rope connection.

[0089] It should be noted that, in this embodiment, the bending unit near the base disk 20 includes:

[0090] Two first pillars 210 are aligned and installed on the base plate 20, and the first pillars 210 are provided with corresponding pin holes;

[0091] The cross shaft connector 211 has a first pin 2111 and a second pin 2112. The first pin 2111 is connected to the first support column 210 to realize two degrees of freedom rotation of the cross shaft connector 211.

[0092] Two second pillars 212 are arranged adjacent to the first pillar 210, and the second pillars 212 are connected to the second pins 2112.

[0093] The unit disk 213 is connected to the second support column 212, which is away from the second pin 2112, and the unit disk 213 is rotated in four degrees of freedom through the cross shaft connector 211 and the second support column 212.

[0094] Multiple unit springs 214 are installed on the outside of the first pillar 210 and / or the second pillar 212 and connected to the base plate 20 and the unit plate 213.

[0095] It should be noted that, except for the bending unit near the base plate 20, in the remaining bending units, the first support 210 of each rear bending unit is mounted on the unit plate 213 of the front bending unit, and each unit spring 214 is connected to the unit plate 213 of the adjacent bending unit to form a continuous robotic arm with two independent movements.

[0096] It should be noted that, in this embodiment, each rope hole of the unit disk 213 of different bending units in the same section of the robotic arm is located on the same vertical line.

[0097] It should be noted that in this embodiment, both the base plate 20 and the unit plate 213 are provided with snap ring cylindrical pins 215 for installing and limiting the unit spring 214. The unit plate 213 located in the middle has snap ring cylindrical pins 215 installed on both sides, while the unit plate 213 located away from the base plate 20 has snap ring cylindrical pins 215 installed only on its lower surface.

[0098] It should be noted that, in this embodiment, the core 13 includes:

[0099] The cylinder 130 has parallel slide rails 1301 spaced apart on its outer periphery, which are fixedly connected to the inner wall of the pre-tightening outer shell 12. It should be noted that in this embodiment, the pre-tightening outer shell 12 adopts a double-layer symmetrical layout inside.

[0100] Two cover plates 131 are respectively installed at both ends of the cylinder 130 to form a sealed cavity. Each cover plate 131 located in the sealed cavity has multiple sets of second positioning wheel assemblies 1310 on its surface. Each cover plate 131 has a through hole for a rope to pass through.

[0101] It should be noted that in this embodiment, the second positioning wheel assembly 1310 located on different cover plate 131 surfaces is symmetrical about the cylinder 130, and is used to adjust the ropes entering and exiting the pre-tensioning compensation mechanism to be in the same vertical direction, thereby reducing the occurrence of rope tangling and bias at the pulley end.

[0102] It should be noted that in this embodiment, the cross-sections of the pre-tightening housing 12 and the cylinder 130 are both regular octagons. Each interior angle of the pre-tightening housing 12 is directly opposite the middle of the side of the cylinder 130, and is used to install the slide rail 1301. This ensures that when the intermediate pulley moves under load, its pressure is always in the normal direction of the side wall of the cylinder 130, reducing the bias pressure of the component force on each part, reducing wear and tear, and improving the service life and smoothness of the device.

[0103] It should be noted that in this embodiment, the number of the first rope 5, the second rope 6, and the pretensioning compensation mechanism is the same.

[0104] It should be noted that, in this embodiment, the ball screw 42 is connected to the output shaft of the motor 41 via a coupling.

[0105] The specific workflow of this invention is as follows:

[0106] The mounting plate is fixed to the work platform. After the four motors are connected to the work platform controller, the controller outputs control signals to the four motors, which drive the ball screws to rotate via couplings. The rotational motion of the screws is converted into the linear displacement of the ball nuts on the rope fixing plates. The rope fixing plates at the upper and lower ends of the ball nuts synchronously pull the first and second ropes. The upper end of the first rope is fixed to a unit plate away from the core, while the second rope forms a symmetrical tension system through reversing pulleys arranged in 180° opposite directions.

[0107] like Figure 9 The diagram shown is a schematic of the active-passive coordinated control of the present invention. Figure 9 (a) is a schematic diagram of the coordinated upward movement of the rope fixing plate. When the motor drives the ball nut of the rope fixing plate to move upward, the first rope 5, as the driven rope, loosens, and the second rope 6 at the lower end of the rope fixing plate, as the driving rope, tightens by an equal amount through the pulley system; conversely, when the motor drives the ball nut of the rope fixing plate to move upward, the first rope 5, as the driven rope, loosens, and the second rope 6, as the driving rope, tightens by an equal amount through the pulley system. Figure 9 (b) is a schematic diagram of the coordinated downward movement of the fixed rope plate. When the ball nut of the fixed rope plate moves downward driven by the motor, the first rope 5, as the active rope, tightens, while the second rope 6 at the lower end of the fixed rope plate, as the driven rope, relaxes by an equal amount through the pulley system. This mechanical coupling ensures that the two ropes always maintain equal and opposite movements. After the first rope changes its distribution diameter through the guide pulley, it enters the main body of the robotic arm. The second rope forms a tension compensation loop through a three-stage path of "second positioning wheel assembly - intermediate pulley - second positioning wheel assembly" of the core and pre-tensioning compensation mechanism.

[0108] The guide rod and helical spring of the pretensioning compensation mechanism respond in real time to changes in rope tension. When the second rope tightens, the helical spring stores energy; when it slacks, the helical spring releases energy to push the intermediate pulley back to its original position. The helical spring is linked to the I-shaped sliding component through a hollow sleeve, maintaining constant tension within its stroke range and effectively suppressing rope slack.

[0109] The first and second ropes are fastened to the top of the continuous robotic arm. The orthogonally distributed first and second rope groups control the two-section robotic arm to bend in a specified direction through antagonistic "retraction-release" motion. The motor only needs to process the single-end drive signal. The continuous robotic arm with independent two-section movement can achieve four degrees of freedom of independent spatial movement by means of the rope hole layout with a 45° phase difference.

[0110] The spring-pulley combination of the pre-tensioning compensation mechanism continuously compensates for system deformation, while the mechanical adaptive mechanism automatically eliminates rope slack. The purely mechanical structure's coordinated control, requiring no complex algorithms, ensures stability during long-term operation and enables rapid response to sudden load changes.

[0111] Specific implementation scenarios of the present invention include the following:

[0112] Scenario 1: Multi-directional bending operation in a narrow space

[0113] The mounting plate is fixed to the working platform, and the drive ropes are retracted and extended through the coordinated control of four motors. When the first section of the robotic arm needs to bend downwards, the motor drives the ball nut on the corresponding degree of freedom to move upwards, tightening the first rope and relaxing the second rope, causing the unit to deflect around the support column; simultaneously, the helical spring of the pre-tension compensation mechanism automatically extends and retracts according to the tension change of the second rope, eliminating slack during the movement. When the second section of the robotic arm bends to the left, the motor drives the ball nut on the corresponding degree of freedom to move downwards, tightening the second rope and relaxing the first rope, which is achieved independently through the 45° phase difference rope hole layout, ensuring that the movement of the two sections of the robotic arm is interference-free. No real-time tension sensor feedback is required throughout the process, simplifying control and reducing costs. This invention, through the design of a two-section continuous robotic arm structure, cleverly maps eight drive ropes into four degrees of freedom for motion control, achieving kinematic dimensionality reduction while maintaining multi-directional bending capability.

[0114] Scenario 2: Dynamic Load Adaptation

[0115] When a sudden load is applied to the unit disk (i.e., the top unit disk of the second robotic arm) away from the core, the increased tension of the first rope causes the helical spring of the pretension compensation mechanism to compress, and the intermediate pulley to displace, releasing the redundant rope. After the load is removed, the helical spring pushes the intermediate pulley to reset, immediately tightening the slack rope. This process is completed autonomously within the mechanical structure, with no system oscillation, demonstrating the reliability of active-passive coordinated control under dynamic conditions. This invention employs an underactuated architecture with four motors driving eight ropes, combined with an innovative spring-pulley composite pretension mechanism, effectively solving the problem of decreased positioning accuracy caused by rope slack.

[0116] The underactuated active-passive cooperative control device for a continuum robot according to the present invention has the following advantages:

[0117] 1. It adopts a double-section continuous structure design, with each section having independent pitch and bending degrees of freedom, achieving a total of 4 degrees of freedom for agile movement. The double-section configuration maps 8 ropes into 4 degrees of freedom, achieving kinematic dimensionality reduction. This configuration is optimized through bionics, enabling multi-directional bending capabilities in confined spaces.

[0118] 2. An underactuated architecture with four motors coupled to drive eight ropes was adopted, and the complex key technical challenges of multi-dimensional control were solved through electromechanical collaborative control;

[0119] 3. A composite pretensioning mechanism combining springs and pulleys is adopted, which passively compensates for rope deformation through elastic elements to achieve dynamic tension maintenance, effectively solving the problem of decreased positioning accuracy caused by slack in traditional flexible cable drive systems;

[0120] 4. A bidirectional tension coordination control mechanism based on a ball screw is adopted, which intelligently couples the drive and preload functions into a single motion unit through integrated design. This mechanism uses a ball screw nut as the core drive unit, with innovative axial extensions at both ends forming tension adjustment interfaces. Specifically, the upper end of the fixed rope plate directly connects to a vertically arranged first rope, undertaking the active posture adjustment function; the lower end of the fixed rope plate guides the second rope vertically upward through a double fixed pulley mechanism, constructing a bidirectional symmetrical tension balance system. When the screw rotates to drive the nut in linear motion, the antagonistic movements of the upper and lower ropes can be realized simultaneously. While the first rope actively adjusts its length, the second rope achieves synchronous compensation through a composite preload mechanism combining pulley switching and spring-pulley combinations. This mechanical coupling method ensures dynamic tension balance.

[0121] This invention, through the symmetrical design of the ball bearing nut and the synergistic effect of the spring-pulley composite mechanism, retains the rapid response characteristics of mechanical compensation while also possessing the precise adjustment capabilities of electronic control, effectively solving the slack problem in traditional cable-driven systems. The overall modular architecture design ensures tension stability while significantly improving the system's energy efficiency and ease of maintenance. The key innovation of this design lies in integrating the drive and pre-tensioning functions into a single motion unit through mechanical intelligent coupling, achieving true mechatronic collaborative control. This invention effectively solves the key technical bottlenecks in cable-driven continuous robots regarding control complexity, tension maintenance, and system reliability, providing an innovative solution for applications with stringent precision and reliability requirements, such as medical robots. Compared to traditional rigid robotic arms, this solution exhibits significant advantages in confined space operation, adaptability to complex environments, and operational dexterity, meeting the high-precision operation requirements of scenarios such as minimally invasive surgery and pipeline inspection.

[0122] Example 2

[0123] like Figures 1 to 8 As shown, this embodiment further improves upon the above embodiments, providing a continuum robot underactuated active-passive cooperative control device, wherein the preload compensation mechanism includes:

[0124] Hollow sleeve 31 is installed on the outer wall of the cylinder 130 of the core 13;

[0125] The helical spring 32 is connected to the hollow sleeve 31;

[0126] The guide rod 33 is connected to the helical spring 32 located away from the hollow sleeve 31, and the guide rod 33 is embedded in the hollow sleeve 31;

[0127] The I-shaped sliding member 34 has shoulders on both sides, with each shoulder positioned on the upper and lower sides of the slide rail 1301 of the core 13. Intermediate pulleys 341 are located on the upper and lower sides of the center of the I-shaped sliding member 34. When external force causes a change in the rope's shape, the position of the I-shaped sliding member 34 is adjusted by a helical spring 32 to achieve tension balance in the rope. Specifically:

[0128] When the second rope 6 tightens due to increased load, the intermediate pulley 341 moves toward the core 13, driving the helical spring 32 to compress and store energy along the slide rail 1301 axially.

[0129] When the second rope 6 slackens, the helical spring 32 releases its stored energy, pushing the intermediate pulley 341 away from the core 13 to compensate for the rope length, ensuring that the first rope 5 and the second rope 6 always maintain optimal tension. This adaptive adjustment mechanism effectively solves the problem of rope slackness or excessive tightness, significantly improving the stability and control accuracy of the robotic arm's movement, and requires no electronic feedback system throughout the entire process. The entire device adopts a compact modular design, seamlessly cooperating with the underactuated control mechanism to jointly construct a highly efficient and reliable motion control system.

[0130] It should be noted that, in this embodiment, the cylinder 130 includes an upper cylinder and a lower cylinder connected by a key, wherein mounting holes are distributed around the connection between the upper cylinder and the lower cylinder for fixing the hollow sleeve 31.

[0131] It should be noted that in the above embodiments, the tangential direction of all pulleys is strictly orthogonal to the center line of the rope hole, ensuring the stability of the transmission process without uneven wear.

[0132] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0133] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0134] Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The reference to "embodiment" herein means that a specific feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily indicate the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0135] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A continuum robot underactuated active-passive cooperative control device, characterized in that, include: The frame body (1) has a mounting plate (11) and a pre-tightening shell (12). The mounting plate (11) and the pre-tightening shell (12) are connected by a slide rod (14). The surface of the mounting plate (11) is provided with multiple sets of first positioning wheel assemblies (110). A core (13) is installed inside the pre-tightening shell (12). Two robotic arms, the two robotic arms having the same structure and being staggered to form a continuous robotic arm with independent movement of two segments, are mounted on the core (13). Each robotic arm has multiple bending units connected in sequence and in the same position. Each bending unit has rope holes distributed in a circumferential direction. Multiple pre-tightening compensation mechanisms are provided, each of which is circumferentially mounted on the core (13). Multiple underactuated control mechanisms, each of which includes: The motor (41) is mounted on the surface of the mounting plate (11); The ball screw (42) is connected at one end to the output shaft of the motor (41) and at the other end to the core (13); A rope fixing plate (43) is assembled on the slide rod (14) and the ball screw (42). The rope fixing plate (43) has a first mounting part (431) and a second mounting part (432). The first rope (5) connects the robotic arm to the first mounting part (431). The second rope (6) is connected at one end to the robotic arm and at the other end through the robotic arm, the pre-tensioning compensation mechanism, and the first positioning wheel assembly (110) in sequence, and is then connected to the second mounting part (432) to form a tension compensation loop for the first rope (5).

2. The underactuated active-passive cooperative control device for a continuum robot according to claim 1, characterized in that, The continuous robotic arm includes: The base plate (20) is mounted on the core (13); The first section of the robotic arm (21) and the second section of the robotic arm (22) are both composed of multiple bending units with the same structure connected in series. Each bending unit located in the first section of the robotic arm (21) is connected in series and then installed on the base plate (20); each bending unit located in the second section of the robotic arm (22) is connected in series and then installed on the first section of the robotic arm (21).

3. The underactuated active-passive cooperative control device for a continuum robot according to claim 2, characterized in that, The rope hole reference line located in the first section of the robotic arm (21) is arranged with a 45° phase difference from the rope hole reference line located in the second section of the robotic arm (22).

4. The underactuated active-passive cooperative control device for a continuum robot according to claim 2, characterized in that, The bending unit near the base disk (20) includes: The first support column (210) is installed on the base plate (20); The cross shaft connector (211) has a first pin (2111) and a second pin (2112), the first pin (2111) being connected to the first support (210) to achieve two degrees of freedom rotation of the cross shaft connector (211); The second support (212) is connected to the second pin (2112); The unit disk (213) is connected to the second support column (212), and the unit disk (213) can rotate in four degrees of freedom based on the cross shaft connector (211) and the second support column (212); Multiple unit springs (214), each unit spring (214) is mounted on the outside of the first pillar (210) and / or the second pillar (212) and connected to the base plate (20) and the unit plate (213).

5. The underactuated active-passive cooperative control device for a continuum robot according to claim 1, characterized in that, The core (13) includes: The cylindrical body (130) has parallel slide rails (1301) spaced apart on its periphery, which are fixedly connected to the inner wall of the pre-tightened outer shell (12); Two cover plates (131) are installed at both ends of the cylinder (130) to form a sealed cavity, wherein each cover plate (131) located in the sealed cavity has multiple sets of second positioning wheel assemblies (1310) on its surface.

6. The underactuated active-passive cooperative control device for a continuum robot according to claim 1, characterized in that, The pre-tensioning compensation mechanism includes: A hollow sleeve (31) is installed on the outer wall of the cylinder (130); A helical spring (32) is connected to the hollow sleeve (31); The guide rod (33) is connected to the helical spring (32), and the guide rod (33) is embedded in the hollow sleeve (31); The I-shaped sliding member (34) has a shoulder, and each shoulder is provided on the upper and lower sides of the slide rail (1301) of the core (13). An intermediate pulley (341) is provided in the middle of the I-shaped sliding member (34).

7. The underactuated active-passive cooperative control device for a continuum robot according to claim 5, characterized in that, The cylinder (130) consists of an upper cylinder and a lower cylinder connected by a key.

8. The underactuated active-passive cooperative control device for a continuum robot according to claim 5, characterized in that, The second positioning wheel assembly (1310) located on different cover plate (131) surfaces is symmetrical about the cylinder (130).

9. The underactuated active-passive cooperative control device for a continuum robot according to claim 5, characterized in that, The cross-sections of the pre-tightening shell (12) and the cylinder (130) are both regular octagons, wherein each interior angle of the pre-tightening shell (12) is opposite to the middle of the side of the cylinder (130).

10. The underactuated active-passive cooperative control device for a continuum robot according to claim 1, characterized in that, The number of the first rope (5), the second rope (6), and the pre-tensioning compensation mechanism is the same.

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