Tail end driving mechanism of continuum robot

Abstract

The invention discloses a tail end driving mechanism of a continuum robot. The tail end driving mechanism comprises a sliding table, a driving box, a driving section flexible tail end pipe, a driven section bent hose and a control unit. The sliding table is arranged along the linear guide rail; the driving box is mounted on the sliding table; the driven section bent hose is connected with the driving box and the driving section flexible tail end pipe, and the driving section flexible tail end pipe is installed at the tail end of the continuum robot. The active section flexible tail end pipe comprises a middle section bunching pipe, a tail end bunching pipe and a retainer; the middle-section bunching tube is positioned in the middle of the active-section flexible tail-end tube and is used for fixing the first-section silk thread; the tail end wire bunching pipe is located at the far end of the active section flexible tail end pipe and used for fixing the second section of silk threads; the retainers are arranged between the middle-section bunching tube and the tail-end bunching tube at intervals; the driven section bent hose comprises an inner-layer long straight pipe and an outer-layer long straight pipe, the inner-layer long straight pipe is connected with the driving box and the driving section flexible tail end pipe, and the outer-layer long straight pipe wraps the inner-layer long straight pipe and the silk threads. The silk thread transmission efficiency is improved, and the stability of the end effector is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of robotics, and in particular to an end effector mechanism for a continuous robot, suitable for tasks requiring high precision and flexibility. Background Technology

[0002] With the development of minimally invasive medical technology, bronchoscopy, gastrointestinal tract, urinary tract, and vascular intervention, as well as other intracavitary navigation and treatment methods, have gradually become important clinical tools. Traditional rigid or semi-flexible endoscopes have significant limitations in reaching complex curved cavities, narrow bifurcated structures, and deep target areas: 1) Limited bending ability: Conventional control mechanisms mostly use single-segment bending or limited degree-of-freedom structures, making it difficult to achieve compliant entry into multi-level cavities or large curvature paths; 2) Insufficient control precision: In deep, multi-branched cavities, the distal attitude is difficult to control precisely, affecting target positioning and operational safety; 3) Difficulty in balancing structural stiffness and flexibility: Single drive or simple bending methods often present significant contradictions between flexibility, controllability, and stability; 4) Lack of effective coupled drive design: Existing continuum robots mostly use segmented independent drive methods, with insufficient inter-segment coordination, resulting in discontinuous bending response, insufficient bending amplitude, or uneven motion.

[0003] In recent years, continuum robots have been widely regarded as an important technological approach to solving the aforementioned problems due to their advantages such as high compliance, ability to achieve large-angle bending, and adaptability to complex spatial structures. However, existing continuum robots still generally face the following technical bottlenecks in the field of medical intervention: (1) Insufficient segmental coordination capability. Most continuum structures still adopt single-segment or weakly coupled structures, making it difficult to achieve coordinated bending between multiple segments and unable to effectively match the complex curvature changes of human body cavities.

[0004] (2) The degree of bending is limited by the structure and drive. Existing designs generally have problems such as limited bending range, decreased stability during extreme bending, easy deformation loss or insufficient output force.

[0005] (3) The driving mode has a low degree of coupling. Traditional driving is mainly based on independent control, which cannot realize coupling driving control based on multi-segment linkage, resulting in insufficient control efficiency and trajectory continuity. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the technical problem this invention aims to solve is to provide an end effector mechanism for a continuum robot.

[0007] The present invention solves the aforementioned technical problem by adopting the following technical solution: A continuous robot end effector mechanism is characterized in that the mechanism includes a slide table, a drive box, an active flexible end tube, a passive bending hose, and a control unit; the slide table is arranged along a linear guide rail, and the drive box is mounted on the slide table; the passive bending hose connects the drive box and the active flexible end tube, and the active flexible end tube is mounted on the end of the continuous robot. The active flexible end tube includes a middle section wire bundle tube, an end wire bundle tube, and a retainer; the middle section wire bundle tube is located in the middle of the active flexible end tube and is used to fix the first section of wire; the end wire bundle tube is located at the far end of the active flexible end tube and is used to fix the second section of wire; the retainer is arranged at intervals between the middle section wire bundle tube and the end wire bundle tube. The passive section bending hose includes an inner long straight tube and an outer long straight tube. The inner long straight tube connects the drive box and the active section flexible end tube, and the outer long straight tube wraps around the inner long straight tube and the outside of the wire.

[0008] Furthermore, the drive box includes a motor, a ball screw, a guide rod, a perforated coupling, a slider, and a wire winding device; the output end of the motor is connected to one end of the ball screw through the perforated coupling, the other end of the ball screw is rotatably connected to the side wall of the drive box, and the slider is slidably connected to the ball screw; one end of the wire winding device is mounted on the slider, and the other end is slidably connected to the guide rod, and both ends of the guide rod are connected to the side wall of the drive box.

[0009] Furthermore, the motor is a servo motor, a stepper motor, or a DC motor.

[0010] Compared with the prior art, the beneficial effects of the present invention are: It can achieve high-precision, multi-segment flexible arm segmented bending control, reduce friction loss, improve wire transmission efficiency, and ensure the repeatability and stability of the end effector. At the same time, the modular design facilitates system installation, debugging and maintenance, meeting the needs of industrial and scientific research applications. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the drive box of the present invention; Figure 3 This is a schematic diagram of the structure of the flexible end tube of the active section of the present invention; Figure 4 This is a flowchart illustrating the driving process of the present invention; Reference numerals: 1-slide table; 2-drive box; 201-motor; 202-ball screw; 203-guide rod; 204-cloverleaf coupling; 205-slider; 206-wire winding device; 3-active section flexible end tube; 301-middle section wire bundle tube; 302-end wire bundle tube; 303-cage; 4-passive section bending hose. Detailed Implementation

[0012] Specific embodiments are given below with reference to the accompanying drawings. These specific embodiments are only used to describe the technical solution of the present invention in detail and are not intended to limit the scope of protection of this application.

[0013] like Figure 1-3 As shown, the present invention provides an end effector drive mechanism for a continuum robot, comprising: Slide 1, as the basic load-bearing structure, is arranged along the linear guide rail to support the drive box 2, the active section flexible end tube 3 and the passive section 4, and provides overall positioning and support functions. The drive box 2, mounted on the slide table 1, contains a motor 201, a ball screw 202, a guide rod 203, a perforated coupling 204, a slider 205, and a wire winding device 206. The output end of the motor is connected to one end of the ball screw 202 via the perforated coupling, and the other end of the ball screw 202 is rotatably connected to the side wall of the drive box. The slider 205 is slidably connected to the ball screw. One end of the wire winding device is mounted on the slider, and the other end is slidably connected to the guide rod. Both ends of the guide rod are connected to the side wall of the drive box. The drive box 2 is responsible for converting control commands into wire extension and retraction power, thereby driving the active section flexible end tube 3 to achieve segmented bending. The active flexible end tube 3, installed at the end of the continuous robot, is the core actuator for achieving end-bending. It can transmit driving force through elastic deformation, enabling controllable bending of the flexible segment, and provides structural support and guidance for the middle section wire bundle tube 301 and the end wire bundle tube 302. The middle section wire bundle tube 301, located in the middle of the active flexible end tube 3, is used to fix the first section of wire and serves as the connection hub between the first and second sections of wire, ensuring wire tension and positioning. The end wire bundle tube 302, installed at the far end of the active flexible end tube 3, is used to fix the second section of wire, achieving stable driving of the end flexible segment by precisely constraining the wire position. The retainer 303 is distributed between the middle section wire bundle tube 301 and the end wire bundle tube 302, and between the middle section wire bundle tube 301 and the passive bending hose 4, with five in each layer, for positioning and guiding the wire, maintaining consistent wire tension, and preventing wire interference or tangling.

[0014] The passive bending hose 4 consists of two layers of long straight tubes, serving as a flexible guide structure for the passive transmission section. This structure ensures that the wire is stably stressed during transmission and undergoes controlled bending under the action of the driving wire, while reducing friction and wear. The inner long straight tube connects the drive box 2 and the active flexible end tube 3, providing a direct force transmission path for the wire and ensuring that the driving force is effectively transmitted from the drive box 2 to the active flexible end tube 3. The outer long straight tube 402 wraps around the inner long straight tube and the wire, providing protection and constraint to prevent the wires from tangling or interfering with each other, while also reducing friction and ensuring the motion accuracy of the continuous flexible section.

[0015] In some alternative implementations, the motor 201 in the drive box 2 can be a servo motor, a stepper motor, or a DC motor, and the lead and material of the ball screw 202 can be selected according to the control accuracy and transmission load requirements.

[0016] In some alternative implementations, the slide 1 may be equipped with fine-tuning bolts or servo drives for adjusting the initial position of the continuum robot or aligning the relative positions of the drive box 2 and the active segment flexible end tube 3.

[0017] In some alternative implementations, the system may be configured with sensor modules, including displacement sensors, angle sensors, or optical measurement units, for real-time monitoring of the end position of the flexible segment, bending angle, and filament condition, in order to optimize control strategies and compensate for friction loss.

[0018] The control unit is connected to the drive box 2, the slide table 1 and each sensor module. The control unit generates control commands based on the pre-input system parameters and sensor information to control the motor 201, ball screw 202 and slider 205 of the drive box 2 to achieve controllable segmented bending motion of the continuous flexible section.

[0019] Specifically, when the continuous robot performs segmented bending motions, the control unit adjusts the wire length via the drive box 2, the slide 1 provides rigid support and linear guidance, and the active flexible end tube 3 and the passive bending hose 4 undergo controllable bending under the traction of the wire. The retainer 303, the middle section wire bundle tube 301, and the end wire bundle tube 302 ensure balanced wire tension and guiding accuracy, while the inner and outer long straight tubes protect the wire transmission path, ensuring the segmented bending accuracy and repeatability of the active flexible end tube 3.

[0020] During implementation, the control unit can adjust the wire output speed of the drive box 2 and the position of the slider 205 in real time to meet different bending angles and end pose requirements; at the same time, the control strategy can be adjusted in a closed loop by monitoring the end displacement and bending angle of the flexible section through the sensor module.

[0021] The infinitesimal element friction analysis module can establish infinitesimal force equations by combining the inner and outer long straight tubes and the sleeve path, and perform integral calculations using the small angle approximation to predict the end wire tension loss and the impact of friction on the end accuracy, providing an optimization basis for the control unit.

[0022] In some alternative embodiments, the active flexible end tube and the passive bending hose 4 can be made of a highly elastic composite material to ensure bending recovery force and fatigue resistance; the retainer 303 and the middle and end wire harness tubes 301 and 302 can be made of wear-resistant alloy or high-strength engineering plastic to reduce wire friction loss and extend system life.

[0023] Through the above structure and implementation method, the continuum robot and drive transmission system of the present invention can achieve high-precision, segmented flexible arm bending control, reduce friction loss, improve end-effector motion accuracy and repeatability, and the modular design of the system facilitates installation, debugging and maintenance.

[0024] In some alternative embodiments, the length, diameter and material of the active section flexible end tube 3 can be selected according to the total length, bending radius and load requirements of the continuous flexible section to ensure the bending accuracy of the end and the load-bearing capacity of the flexible section; the active section flexible end tube 3 can be made of high elastic polymer or carbon fiber composite material to take into account bending recovery force, fatigue resistance and long-term stability.

[0025] In some alternative embodiments, the middle section cable tie tube 301 and the end cable tie tube 302 can be made of wear-resistant alloy or high-strength engineering plastic to reduce wire friction loss and improve system life. The inner diameter, wall thickness, and length of the cable tie tubes 301 and 302 can be designed according to the wire diameter and the bending requirements of the flexible section to ensure that the wire maintains tension balance and guiding accuracy during transmission.

[0026] In some alternative implementations, the cage 303 may be designed with adjustable segments, allowing users to adjust the spacing between each cage layer and the wire guide angle according to the length and bending radius of the continuous flexible segment, thereby adapting to different working ranges and flexible segment curvature requirements.

[0027] The inner and outer straight tubes 401 and 402 of the passive bending flexible tube 4 can be optimized through material selection, thickness, and stiffness ratio to achieve controlled bending under the action of the driving wire, while reducing friction and energy loss. In some optional embodiments, the inner straight tube 3 can be provided with an inner diameter guide groove to further constrain the wire movement path and prevent the wire from deviating or knotting under high bending conditions; the outer straight tube 4 can be provided with an anti-slip coating or lined with a low-friction material to reduce the coefficient of friction and improve the response speed and accuracy of the finite element flexible end tube 3.

[0028] In the drive box 2, the motor 201 can be a servo motor, a stepper motor, or a DC motor, and the ball screw 202 can adopt different lead designs to achieve different linear displacement accuracies and transmission efficiencies. The slider 205 moves linearly through the guide rod 203, driving the wire winding device 206 to output wire, thereby realizing the bending control of the active flexible end tube 3 and the passive bending hose 4. In some optional embodiments, the wire winding device 206 can be equipped with a tension spring or a friction adjustment mechanism to maintain appropriate wire tension and prevent slack or excessive tightness from causing end movement errors.

[0029] In some alternative implementations, the slide 1 may integrate fine-tuning bolts or a servo drive mechanism for precisely adjusting the initial position of the continuum robot or aligning the relative positions of the drive box 2 and the active segment flexible end tube 3 during experimentation or debugging. The slide 1 may be made of high-rigidity aluminum alloy or steel to ensure structural stability during long-term operation.

[0030] In some alternative implementations, the continuum robot system may be configured with sensor modules, including displacement sensors, angle sensors, force sensors, or optical measurement units, for real-time monitoring of the end position, bending angle, filament tension, and stress conditions of the flexible segment. The sensor information can be fed back to the control unit to achieve closed-loop control, thereby further improving the control accuracy and repeatability of the active segment flexible end tube 3.

[0031] The control unit is connected to the drive box 2, the slide table 1, and the sensor module. By controlling the movement of the motor 201, ball screw 202, and slider 205 in the drive box 2, the length of the wire is adjusted, thereby driving the active flexible end tube 3 and the passive bending hose 4 to produce segmented bending actions. The control unit can dynamically adjust the control strategy according to preset system parameters, real-time sensor information, and micro-element friction analysis results.

[0032] During implementation, when the continuum robot performs segmented bending actions, the control unit adjusts the wire length through the drive box 2, the slide table 1 provides rigid support and linear guidance, the active section flexible end tube 3, the middle section wire bundle tube 301, the end wire bundle tube 302 and the retainer 303 work together to ensure balanced wire tension and stable transmission path, the passive section bending hose 4 provides flexible guidance, and the inner and outer long straight tubes protect the wire transmission path, realizing high-precision bending of the end flexible section.

[0033] In some alternative implementations, the active flexible end tube 3 and the passive bending hose 4 can be configured with different radii of curvature and lengths according to task requirements, and the material can be a highly elastic composite material to ensure that bending stability and fatigue resistance are maintained during long-term operation.

[0034] The drive box 2 and the slide table 1 can be modularly combined, facilitating overall installation, debugging, and maintenance. In some optional embodiments, the slide table 1 can be equipped with adjustable fixed points to enable rapid adjustment of the initial position of the continuous robot, while ensuring the integrity of the force transmission chain and the bending accuracy of the flexible segment.

[0035] In some alternative implementations, the control unit can be located outside the operating area to avoid interfering with the bending operation of the flexible segment. Data acquisition, transmission, processing, and drive control can be achieved through an industrial control computer, PLC, and touchscreen. The control unit can display the flexible segment's pose and the filament's status in real time, facilitating experimental and operational management.

[0036] Through the above structure and implementation method, the continuum robot and drive transmission system of the present invention can achieve high-precision, multi-segment flexible arm segmented bending control, reduce friction loss, improve end-effector motion accuracy and repeatability, and at the same time achieve system modularity, convenient installation, simple debugging and long-term reliable operation.

[0037] like Figure 4 As shown, the process of the end effector mechanism for the continuum robot of the present invention includes the following steps: Step S1, System Initialization: Before starting the continuous robot, the control unit performs initial positioning of the slide 1 to ensure that the drive box 2 and the end flexible section are in the preset initial position; the initialization parameters include the initial length of the filament, the initial pose of the active section flexible end tube and the passive section bending hose 4, the filament tension setting value and the flexible section material parameters. Step S2: Drive box controls wire length: The control unit calculates the amount of wire extension and retraction based on the desired bending angle at the end and the length of the flexible section, controls the movement of motor 201 and ball screw 202 in drive box 2, drives slider 205 to move along guide rod 203, thereby adjusting wire length; Step S3: The slider drives the wire to move: The wire winding device 206 outputs the wire, which is transmitted to the active section flexible end tube 3 through the inner long straight tube. The middle section wire bundle tube 301 and the end wire bundle tube 302 ensure the wire guidance and tension balance, and drive the active section flexible end tube 3 and the passive section bending hose 4 to bend to the predetermined posture. Step S4, Flexible Segment Bending Adjustment: The active segment flexible end tube 3 bends under the traction of the wire, the cage 303 guides the movement of the wire, the inner and outer long straight tubes ensure the stability of the wire transmission path, and at the same time the passive segment bending hose 4 produces controlled bending, so that the flexible segment reaches the expected posture. Step S5, Calculation of friction and tension feedback: Based on the method of infinitesimal elements, the control unit performs infinitesimal segment calculations on the inner and outer straight tubes and the sleeve path, estimates the friction force and wire tension loss of each segment, accumulates the force state of the active section flexible end tube 3, and feeds the tension information back to the control unit for closed-loop regulation. Step S6, End Position Detection: The sensor module (displacement sensor, angle sensor or optical measurement unit) detects the actual position, bending angle and filament status of the active flexible end tube 3 and the passive bending hose 4 in real time, and sends the detection data to the control unit. Step S7, Deviation Judgment: The control unit compares the end pose and filament state with the desired pose to determine whether the active flexible end tube 3 has reached the target bending angle and position accuracy, and whether the deviation is within the allowable range. Step S8, Deviation Correction and Closed-Loop Adjustment: If the end-effector position deviation exceeds the allowable range, the control unit recalculates the wire adjustment amount, adjusts the output of the drive box 2 motor 201 and ball screw 202, and drives the wire to extend and retract through the slider 205 to correct the bending angle of the active section flexible end tube 3 and the passive section bending hose 4; if the deviation is within the allowable range, the current control parameters are maintained, and the next operation step is entered or the current posture is maintained. Step S9, Cyclic Execution and Dynamic Adjustment: After the end pose reaches the expected requirements, if the continuous flexible segment needs to perform further bending operations or dynamic tasks, the control unit repeats steps S2 to S8 to achieve continuous bending or multi-segment flexible segment control.

[0038] Step S10, End Operation: When the continuous flexible segment completes the preset task or reaches the expected pose accuracy, the control unit stops the movement of the drive box 2 and slider 205, the active segment flexible end tube 3 remains stationary, and the system enters standby mode.

[0039] Through the above steps, the embodiments of the present invention can achieve high-precision segmented flexible arm bending control, the wire friction loss can be dynamically compensated, and the actual posture of the active flexible end tube 3 and the passive bending hose 4 is consistent with the desired posture, thereby realizing closed-loop control and dynamic adjustment.

[0040] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A continuous robot end effector mechanism, characterized in that, The mechanism includes a slide, a drive box, an active flexible end tube, a passive flexible flexible hose, and a control unit; the slide is arranged along a linear guide rail, and the drive box is mounted on the slide; the passive flexible flexible hose connects the drive box and the active flexible end tube, and the active flexible end tube is mounted at the end of the continuum robot; The active flexible end tube includes a middle section wire bundle tube, an end wire bundle tube, and a retainer; the middle section wire bundle tube is located in the middle of the active flexible end tube and is used to fix the first section of wire; the end wire bundle tube is located at the far end of the active flexible end tube and is used to fix the second section of wire. The retainer is spaced between the middle section of the cable tray and the end section of the cable tray; The passive section bending hose includes an inner long straight tube and an outer long straight tube. The inner long straight tube connects the drive box and the active section flexible end tube, and the outer long straight tube wraps around the inner long straight tube and the outside of the wire.

2. The end effector of the continuum robot according to claim 1, characterized in that, The drive box includes a motor, a ball screw, a guide rod, a perforated coupling, a slider, and a wire winding device. The output end of the motor is connected to one end of the ball screw through the perforated coupling, and the other end of the ball screw is rotatably connected to the side wall of the drive box. The slider is slidably connected to the ball screw. One end of the wire winding device is mounted on the slider, and the other end is slidably connected to the guide rod. Both ends of the guide rod are connected to the side wall of the drive box.

3. The end effector mechanism for a continuum robot according to claim 2, characterized in that, The motor is a servo motor, a stepper motor, or a DC motor.

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