A compact rope-driven wide-range variable stiffness joint based on the lever principle

Abstract

The present invention relates to a compact rope-driven wide-range variable stiffness joint based on the lever principle, comprising: a base module; a decoupling mechanism connected to the base of the base module and disposed above the base module; a driving mechanism disposed above a driven wheel of the decoupling mechanism; a variable stiffness mechanism disposed above the driving mechanism; and an output mechanism disposed at the top of the compact rope-driven wide-range variable stiffness joint based on the lever principle and connected to the variable stiffness mechanism. The decoupling mechanism in the compact rope-driven wide-range variable stiffness joint based on the lever principle has the advantages of a compact structure, fast response, no reverse offset, and small error, thereby achieving the technical effect of a stiffness variation range from 0 to infinity.

Description

Technical Field

[0001] The present invention relates to the field of mechanical arms, and in particular to a compact rope-driven wide-range variable stiffness joint based on the lever principle. Background Art

[0002] With the continuous development of robotics, adaptable, flexible, and compliant robotic arms are becoming increasingly important. Traditional industrial robotic arms are difficult to use in unstructured environments due to their high mass inertia and joint stiffness. To address these issues, cable-driven robotic arms and flexible joint technology have become a hot topic of research in recent years. Flexible joint technology, which mimics the flexibility and mobility of biological joints, is widely used in robotics, prosthetics, and other fields. The core of flexible joint technology lies in the ability to dynamically adjust the stiffness of the joint during movement through special structural design and material application, while also maintaining good flexibility and adaptability.

[0003] Variable stiffness joints are an important part of flexible joint technology. They can improve the system's compliance and adaptability in unstructured environments, thereby improving the flexibility and safety of the robotic arm system. The core of the variable stiffness joint is to achieve dynamic adjustment of stiffness through mechanical structure or physical principles. The technical principles of variable stiffness joints usually include designs based on permanent magnetic springs. The stiffness of the joint is adjusted by changing the magnetic field strength and distribution between permanent magnets. Adjusting the relative position and arrangement of permanent magnets can change the magnetic field force, thereby achieving stiffness adjustment. Based on the design of the cam mechanism, the fulcrum position of the lever is adjusted by rotating the cam, thereby changing the stiffness of the joint. For example, the lever-type variable stiffness joint based on the involute profile cam can achieve decoupling of stiffness and deflection angle. Based on the design of the spring leaf, the stiffness is changed by adjusting the effective length or shape of the spring leaf. Summary of the Invention

[0004] The present invention provides a compact rope-driven large-range variable stiffness joint based on the lever principle, aiming to solve at least one of the technical problems existing in the prior art.

[0005] The technical solution of the present invention is a compact rope-driven wide-range variable stiffness joint based on the lever principle, comprising:

[0006] Base module;

[0007] a decoupling mechanism, the decoupling mechanism being connected to the base of the base module and being arranged above the base module;

[0008] a driving mechanism, the driving mechanism being arranged above the driven wheel of the decoupling mechanism;

[0009] a variable stiffness mechanism, the variable stiffness mechanism being arranged above the driving mechanism;

[0010] The output mechanism is placed on the top of a compact rope-driven large-range variable stiffness joint based on the lever principle, and is connected to the variable stiffness mechanism.

[0011] Furthermore, the base module includes a joint motor, a stiffness adjustment motor, a stiffness adjustment motor winding wheel connected to the output shaft of the stiffness adjustment motor, a motor mounting plate, a motor driver mounting plate, a base and a base pulley assembly.

[0012] The joint motor and the stiffness adjustment motor are arranged at the rear end of the base, the axis of the joint motor and the axis of the stiffness adjustment motor are parallel, and the fixed end of the joint motor and the fixed end of the stiffness adjustment motor are fixed below the motor mounting plate by bolts and are on the same horizontal plane;

[0013] The motor mounting plate is arranged below the base, the motor mounting plate and the base are connected by a copper column, the motor driver mounting plate is installed perpendicular to the motor mounting plate and is fixed to the motor mounting plate by bolts; the motor driver mounting plate is used to drive the joint motor and the stiffness adjustment motor to move;

[0014] The base pulley group is installed on the lower surface of the base by bolts. The base pulley group includes a first high guide pulley and a first low guide pulley. The pulley directions of the first high guide pulley and the first low guide pulley are tangent to the pulley direction of the stiffness adjustment motor winding wheel.

[0015] Furthermore, the decoupling mechanism is installed above the base of the base module, and the decoupling mechanism includes a driven wheel, a first reversing winding wheel, a second reversing winding wheel, a coupling rope, a stiffness adjustment driving rope and a direction-changing pulley set;

[0016] The driven wheel is arranged above the base of the base module, and the driven wheel is installed above the base of the base module and is connected to the base through a deep groove ball bearing. The first reversing winding wheel and the second reversing winding wheel are respectively arranged on the sides of the driven wheel; the upper and lower surfaces of the driven wheel are provided with wire grooves, and the coupling rope and the stiffness adjustment drive rope are circumferentially wound in the wire grooves on the upper and lower surfaces of the driven wheel. The winding shape of the coupling rope and the stiffness adjustment drive rope is coaxial with the driven wheel, and the changing pulley group is arranged above the driven wheel.

[0017] Furthermore, the coupling rope includes a first coupling rope and a second coupling rope,

[0018] One end of the first coupling rope is fixed to the base of the base module, and the other end of the first coupling rope is fixed to the driving disk of the driving mechanism. The first coupling rope is wound circumferentially in the wire grooves on the upper and lower surfaces of the driven wheel through the first reversing winding wheel;

[0019] One end of the second coupling rope is fixed to the base of the base module, and the other end of the second coupling rope is fixed to the driving disk of the driving mechanism. The second coupling rope is circumferentially wound in the wire grooves on the upper and lower surfaces of the driven wheel through the second reversing winding wheel.

[0020] Further, the direction-changing pulley assembly includes a second high guide pulley and a second low guide pulley, and the stiffness-adjusting drive rope includes a first stiffness-adjusting drive rope and a second stiffness-adjusting drive rope;

[0021] One end of the first stiffness adjustment drive rope is wound around and fixed on the stiffness adjustment motor winding wheel, and the other end of the first stiffness adjustment drive rope is wound around and fixed on the Archimedean spiral disk of the stiffness variable mechanism. The first stiffness adjustment drive rope is wound circumferentially in the wire grooves on the upper and lower surfaces of the driven wheel through the first reversing winding wheel. The first high guide pulley and the second low guide pulley of the base module are used together to guide the first stiffness adjustment drive rope from the stiffness adjustment motor winding wheel of the base module to the Archimedean spiral disk of the stiffness variable mechanism.

[0022] One end of the second stiffness adjustment drive rope is wound around and fixed on the stiffness adjustment motor winding wheel, and the winding direction is opposite to that of the first stiffness adjustment drive rope. The other end of the second stiffness adjustment drive rope is wound around and fixed on the Archimedes spiral disk of the stiffness variable mechanism, and the winding direction is opposite to that of the first stiffness adjustment drive rope. The second stiffness adjustment drive rope is circumferentially wound in the wire grooves on the upper and lower surfaces of the driven wheel through the second reversing winding wheel. The first low guide pulley and the second high guide pulley of the base module are jointly used to guide the second stiffness adjustment drive rope from the stiffness adjustment motor winding wheel to the Archimedes spiral disk of the stiffness variable mechanism.

[0023] Further, the drive mechanism includes an input shaft, a drive plate, a first fulcrum pivot, and a second fulcrum pivot;

[0024] The output shaft of the joint motor and the center axis of the drive disk are respectively coaxial with the input shaft, and the output shaft of the joint motor and the center axis of the drive disk are respectively connected to the input shaft;

[0025] The lower end of the input shaft is connected to the base of the base module through a deep groove ball bearing, the driven wheel of the decoupling mechanism is connected to the input shaft through a deep groove ball bearing, the driving disc is installed above the driven wheel of the decoupling mechanism through a washer, and the driving disc and the input shaft are fixed by a flat key;

[0026] A linear slide groove is provided on the driving disk, and the linear slide groove passes through the central axis position of the driving disk. The first fulcrum pivot and the second fulcrum pivot are installed on the upper surface of the linear slide groove of the driving disk through plug bolts and bearings and are symmetrically arranged, wherein the bearing is located in the linear slide groove of the driving disk and the movement mode of the bearing is pure rolling motion, so that the first fulcrum pivot and the second fulcrum pivot can slide relative to the driving disk.

[0027] Furthermore, the variable stiffness mechanism includes an Archimedean spiral disk, a first lever, a second lever, and an output shaft, wherein the first fulcrum pivot of the driving mechanism, the second fulcrum pivot of the driving mechanism, the Archimedean spiral disk, the lever, and the spring pressure plate are stacked;

[0028] The Archimedes spiral disk is installed above the driving disk of the driving mechanism, the Archimedes spiral disk is connected to the driving disk through a washer, and the Archimedes spiral disk is connected to the input shaft of the driving mechanism through a deep groove ball bearing.

[0029] The Archimedean spiral disk is provided with an Archimedean spiral groove, and the first fulcrum pivot and the second fulcrum pivot of the driving mechanism are relatively parallel to the axis of the Archimedean spiral disk. The first fulcrum pivot and the second fulcrum pivot of the driving mechanism pass through the Archimedean spiral groove and can slide relative to the Archimedean spiral disk in the Archimedean spiral groove. The middle portion of the Archimedean spiral disk is connected to the output shaft via a deep groove ball bearing and an elastic washer.

[0030] The upper and lower surfaces of the first lever and the second lever are both provided with linear grooves, the top end of the first fulcrum pivot of the driving mechanism is placed in the linear groove on the lower surface of the first lever and can slide relatively, and the top end of the second fulcrum pivot of the driving mechanism is placed in the linear groove on the lower surface of the second lever and can slide relatively.

[0031] Furthermore, the output mechanism includes a first spring pressure plate, a first spring, a second spring, a first spring central shaft, a second spring pressure plate, a third spring, a fourth spring, a second spring central shaft and an output disk.

[0032] The center hole of the first spring pressure plate passes through and is arranged at the midpoint of the first spring center axis, and the lower end of the first spring pressure plate is connected to the first lever of the variable stiffness mechanism through an elastic retaining ring; the lower end of the first spring pressure plate is placed in a linear groove on the upper surface of the first lever and can slide relative to the first lever; the first spring center axis passes through the center hole of the first spring pressure plate, and the first spring pressure plate can slide on the first spring center axis; the first spring center axis is arranged horizontally, and the two ends of the first spring center axis are respectively fixed to the inner wall of the output disk, the first spring and the second spring are respectively arranged on both sides of the center hole of the first spring pressure plate, and the two ends of the first spring and the second spring are respectively fixed between the output disk and the center hole of the first spring pressure plate by spring fastening rings;

[0033] The center hole of the second spring pressure plate passes through and is arranged at the midpoint of the second spring center axis, and the lower end of the second spring pressure plate is connected to the second lever of the variable stiffness mechanism through an elastic retaining ring; the lower end of the second spring pressure plate is placed in the linear groove on the upper surface of the second lever and can slide relative to the second lever; the second spring center axis passes through the center hole of the second spring pressure plate, and the second spring pressure plate can slide on the second spring center axis; the second spring center axis is arranged horizontally, and the two ends of the second spring center axis are respectively fixed to the inner wall of the output disk, the third spring and the fourth spring are respectively arranged on both sides of the center hole of the second spring pressure plate, and the two ends of the third spring and the fourth spring are respectively fixed between the output disk and the center hole of the second spring pressure plate through spring fastening rings.

[0034] Furthermore, the output disc is mounted on the end of the output shaft via a nut and a washer, the output disc is fixed in position via an elastic retaining ring and connected to the output shaft of the variable stiffness mechanism via a deep groove ball bearing, and the output disc is coaxially arranged with the input shaft of the variable stiffness mechanism;

[0035] The central axis of the spring passes horizontally through the hole of the output disk, and both ends of the central axis of the spring are fixed to the output disk through bolts and a pressure plate.

[0036] Furthermore, the present invention also proposes a robotic arm, comprising the compact rope-driven large-range variable stiffness joint based on the lever principle.

[0037] The beneficial effects of the present invention are:

[0038] The decoupling mechanism in the compact rope-driven large-range variable stiffness joint based on the lever principle is equivalent to a movable pulley set wound on a bearing, which makes the driven wheel rotate at an angular velocity of half the joint angular velocity, so that the rope lengths at both ends of the first drive rope and the second drive rope are the same, ensuring that the relative angle between the Archimedean spiral disk and the joint angle does not change, thereby achieving the purpose of decoupling; the variable stiffness mechanism changes the rotation of the Archimedean spiral disk into the translation of the first fulcrum pivot and the second fulcrum pivot through the Archimedean spiral groove of the Archimedean spiral disk, changes the force arm length of the first lever and the second lever, and changes the transmission ratio between the elastic force and the output torque. The decoupling mechanism in the compact rope-driven large-range variable stiffness joint based on the lever principle has the advantages of compact structure, fast response, no reverse virtual position, small error, etc., and achieves the technical effect of a stiffness change range from 0 to infinity. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is the overall structure diagram of the compact rope-driven large-range variable stiffness joint based on the lever principle.

[0040] Figure 2 This is the overall structural diagram of the dorsal side of a compact rope-driven large-range variable stiffness joint based on the lever principle (output disk hidden).

[0041] Figure 3 This is the structural diagram of the upper middle side of a compact rope-driven large-range variable stiffness joint based on the lever principle (the output disk and Archimedean spiral disk are hidden).

[0042] 1. Reference numerals: 100, base module; 110, joint motor; 120, stiffness adjustment motor; 130, stiffness adjustment motor winding wheel; 140, motor mounting plate; 150, motor driver mounting plate; 160, base; 170, base pulley assembly; 171, first high guide pulley; 172, first low guide pulley; 200, decoupling mechanism; 210, driven pulley; 220, first reversing winding wheel; 230, second reversing winding wheel; 240, coupling rope; 241, first coupling rope; 242, second coupling rope; 250, stiffness adjustment drive rope; 251, first stiffness adjustment drive rope; 252, second stiffness adjustment drive rope; 260, change-of-direction pulley assembly; 261, second high guide pulley; 262, second low guide pulley; 300, driving mechanism; 310, input shaft; 320, driving disk; 330, first fulcrum pivot; 340, second fulcrum pivot; 400, variable stiffness mechanism; 410, Archimedean spiral; 420, first lever; 430, second lever; 440, output shaft; 500, output mechanism; 510, first spring pressure plate; 520, first spring; 530, second spring; 540, first spring central axis; 550, second spring pressure plate; 560, third spring; 570, fourth spring; 580, second spring central axis; 590, output disk. DETAILED DESCRIPTION

[0043] The following will be combined with the embodiments and drawings to clearly and completely describe the concept, specific structure and technical effects of the present invention so as to fully understand the purpose, scheme and effect of the present invention. It should be noted that the embodiments and features in the embodiments of this application can be combined with each other unless there is a conflict.

[0044] It should be noted that, unless otherwise specified, when a feature is referred to as being "fixed" or "connected" to another feature, it may be directly fixed or connected to the other feature or indirectly fixed or connected to the other feature. Furthermore, terms such as "upper," "lower," "left," "right," "top," and "bottom" used in this disclosure are intended solely to describe the relative positions of the components of the disclosure as shown in the accompanying drawings.

[0045] In addition, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. The terms used in this specification are only for describing specific embodiments and are not intended to limit the present invention. The term "and / or" as used herein includes any combination of one or more of the related listed items.

[0046] It should be understood that although the terms first, second, third, etc. may be used to describe various elements in the present disclosure, these elements should not be limited to these terms. These terms are only used to distinguish elements of the same type from each other. For example, a first element may also be referred to as a second element, and similarly, a second element may also be referred to as a first element without departing from the scope of the present disclosure.

[0047] Reference Figures 1 to 3 In some embodiments, the technical solution of the present invention is a compact rope-driven large-range variable stiffness joint based on the lever principle, referring to Figure 1 and Figure 2 The compact rope-driven large-range variable stiffness joint based on the lever principle includes:

[0048] Base module 100;

[0049] a decoupling mechanism 200 , the decoupling mechanism 200 being connected to the base 160 of the base module 100 and being disposed above the base module 100 ;

[0050] a driving mechanism 300 , the driving mechanism 300 being disposed above the driven wheel 210 of the decoupling mechanism 200 ;

[0051] a variable stiffness mechanism 400 , the variable stiffness mechanism 400 being disposed above the driving mechanism 300 ;

[0052] The output mechanism 500 is placed on the top of the compact rope-driven large-range variable stiffness joint based on the lever principle, and the output mechanism 500 is connected to the variable stiffness mechanism 400.

[0053] The beneficial effects of the present invention are:

[0054] The decoupling mechanism 200 in the compact rope-driven large-range variable stiffness joint based on the lever principle is equivalent to a movable pulley set wound on a bearing, which makes the driven wheel 210 rotate at an angular velocity of half the joint angular velocity, so that the rope lengths at both ends of the first drive rope and the second drive rope are the same, ensuring that the relative angle between the Archimedean spiral disk 410 and the joint angle does not change, thereby achieving the purpose of decoupling; the variable stiffness mechanism 400 changes the rotation of the Archimedean spiral disk 410 into the translation of the first fulcrum pivot 330 and the second fulcrum pivot 340 through the Archimedean spiral groove of the Archimedean spiral disk 410, changes the force arm length of the first lever 420 and the second lever 430, and changes the transmission ratio between the elastic force and the output torque. The decoupling mechanism 200 in the compact rope-driven large-range variable stiffness joint based on the lever principle has the advantages of compact structure, fast response, no reverse virtual position, and small error, and achieves the technical effect of a stiffness change range from 0 to infinity.

[0055] Further, refer to Figure 1 and Figure 2 The base module 100 includes a joint motor 110, a stiffness adjustment motor 120, a stiffness adjustment motor reel 130 connected to the output shaft of the stiffness adjustment motor 120, a motor mounting plate 140, a motor driver mounting plate 150, a base 160 and a base pulley assembly 170.

[0056] The joint motor 110 and the stiffness adjustment motor 120 are arranged at the rear end of the base 160, the axis of the joint motor 110 is parallel to the axis of the stiffness adjustment motor 120, and the fixed end of the joint motor 110 and the fixed end of the stiffness adjustment motor 120 are fixed to the bottom of the motor mounting plate 140 by bolts and are on the same horizontal plane;

[0057] The motor mounting plate 140 is disposed below the base 160 , and the motor mounting plate 140 and the base 160 are connected by a copper column. The motor driver mounting plate 150 is installed perpendicular to the motor mounting plate 140 and is fixed to the motor mounting plate 140 by bolts; the motor driver mounting plate 150 is used to drive the joint motor 110 and the stiffness adjustment motor 120 to move;

[0058] The base pulley assembly 170 is mounted on the lower surface of the base 160 by bolts. The base pulley assembly 170 includes a first high guide pulley 171 and a first low guide pulley 172. The pulley directions of the first high guide pulley 171 and the first low guide pulley 172 are tangent to the pulley direction of the stiffness adjustment motor winding wheel 130.

[0059] Further, refer to Figure 1 and Figure 2 The decoupling mechanism 200 is installed above the base 160 of the base module 100, and the decoupling mechanism 200 includes a driven wheel 210, a first reversing winding wheel 220, a second reversing winding wheel 230, a coupling rope 240, a stiffness adjustment driving rope 250 and a direction-changing pulley set 260;

[0060] The driven wheel 210 is arranged above the base 160 of the base module 100. The driven wheel 210 is installed above the base 160 of the base module 100 and is connected to the base 160 through a deep groove ball bearing. The first reversing winding wheel 220 and the second reversing winding wheel 230 are respectively arranged on the sides of the driven wheel 210; the upper and lower surfaces of the driven wheel 210 are provided with wire grooves, and the coupling rope 240 and the stiffness adjustment drive rope 250 are circumferentially wound in the wire grooves on the upper and lower surfaces of the driven wheel 210. The winding shape of the coupling rope 240 and the stiffness adjustment drive rope 250 is coaxial with the driven wheel 210, and the changing pulley group 260 is arranged above the driven wheel 210.

[0061] Specifically, the decoupling principle is that the decoupling mechanism 200 is equivalent to a movable pulley set wound on a bearing, so that the driven wheel 210 rotates at an angular velocity half of the joint angular velocity, so that the first stiffness adjustment drive rope 251 and the second stiffness adjustment drive rope 252 have the same length at both ends, ensuring that the relative angle between the Archimedean spiral disk 410 and the joint angle does not change, thereby achieving the purpose of decoupling.

[0062] Further, refer to Figure 1 and Figure 2 The coupling rope 240 includes a first coupling rope 241 and a second coupling rope 242.

[0063] One end of the first coupling rope 241 is fixed to the base 160 of the base module 100, and the other end of the first coupling rope 241 is fixed to the driving disk 320 of the driving mechanism 300. The first coupling rope 241 is wound circumferentially in the grooves on the upper and lower surfaces of the driven wheel 210 through the first reversing winding wheel 220;

[0064] One end of the second coupling rope 242 is fixed to the base 160 of the base module 100, and the other end of the second coupling rope 242 is fixed to the driving disk 320 of the driving mechanism 300. The second coupling rope 242 is wound circumferentially in the wire grooves on the upper and lower surfaces of the driven wheel 210 through the second reversing winding wheel 230.

[0065] Further, refer to Figure 1 The direction-changing pulley set 260 includes a second high guide pulley 261 and a second low guide pulley 262 , and the stiffness-adjusting driving rope 250 includes a first stiffness-adjusting driving rope 251 and a second stiffness-adjusting driving rope 252 ;

[0066] One end of the first stiffness adjustment drive rope 251 is wound around and fixed on the stiffness adjustment motor reel 130, and the other end of the first stiffness adjustment drive rope 251 is wound around and fixed on the Archimedes spiral disk 410 of the stiffness variable mechanism 400. The first stiffness adjustment drive rope 251 is wound circumferentially in the wire grooves on the upper and lower surfaces of the driven wheel 210 through the first reversing reel 220. The first high guide pulley 171 and the second low guide pulley 262 of the base module 100 are used together to guide the first stiffness adjustment drive rope 251 from the stiffness adjustment motor reel 130 of the base module 100 to the Archimedes spiral disk 410 of the stiffness variable mechanism 400.

[0067] One end of the second stiffness adjustment drive rope 252 is wound around and fixed on the stiffness adjustment motor winding wheel 130, and the winding direction is opposite to that of the first stiffness adjustment drive rope 251. The other end of the second stiffness adjustment drive rope 252 is wound around and fixed on the Archimedes spiral disk 410 of the stiffness variable mechanism 400, and the winding direction is opposite to that of the first stiffness adjustment drive rope 251. The second stiffness adjustment drive rope 252 is circumferentially wound in the wire grooves on the upper and lower surfaces of the driven wheel 210 through the second reversing winding wheel 230. The first low guide pulley 172 and the second high guide pulley 261 of the base module 100 are jointly used to guide the second stiffness adjustment drive rope 252 from the stiffness adjustment motor winding wheel 130 to the Archimedes spiral disk 410 of the stiffness variable mechanism 400.

[0068] Further, refer to Figure 1 and Figure 2 , the driving mechanism 300 includes an input shaft 310, a driving disk 320, a first fulcrum pivot 330 and a second fulcrum pivot 340;

[0069] The output shaft of the joint motor 110 and the center axis of the driving disk 320 are respectively coaxial with the input shaft 310 , and the output shaft of the joint motor 110 and the center axis of the driving disk 320 are respectively connected to the input shaft 310 ;

[0070] The lower end of the input shaft 310 is connected to the base 160 of the base module 100 via a deep groove ball bearing. The driven pulley 210 of the decoupling mechanism 200 is connected to the input shaft 310 via a deep groove ball bearing. The drive disc 320 is installed above the driven pulley 210 of the decoupling mechanism 200 via a washer. The drive disc 320 and the input shaft 310 are fixed via a flat key.

[0071] A linear slide groove is provided on the driving disk 320, and the linear slide groove passes through the central axis position of the driving disk 320. The first fulcrum pivot 330 and the second fulcrum pivot 340 are installed on the upper surface of the linear slide groove of the driving disk 320 by plugging bolts and bearings and are symmetrically arranged, wherein the bearing is located in the linear slide groove of the driving disk 320 and the movement mode of the bearing is pure rolling motion, so that the first fulcrum pivot 330 and the second fulcrum pivot 340 can slide relative to the driving disk 320.

[0072] Further, refer to Figure 1 and Figure 2 The variable stiffness mechanism 400 includes an Archimedean spiral disk 410, a first lever 420, a second lever 430, and an output shaft 440, wherein the first fulcrum pivot 330 of the driving mechanism 300, the second fulcrum pivot 340 of the driving mechanism 300, the Archimedean spiral disk 410, the lever, and the spring pressure plate are stacked;

[0073] The Archimedes spiral disk 410 is installed above the driving disk 320 of the driving mechanism 300. The Archimedes spiral disk 410 is connected to the driving disk 320 through a washer. The Archimedes spiral disk 410 is connected to the input shaft 310 of the driving mechanism 300 through a deep groove ball bearing.

[0074] The Archimedean spiral disc 410 is provided with an Archimedean spiral groove. The first fulcrum pivot 330 and the second fulcrum pivot 340 of the driving mechanism 300 are relatively parallel to the axis of the Archimedean spiral disc 410. The first fulcrum pivot 330 and the second fulcrum pivot 340 of the driving mechanism 300 pass through the Archimedean spiral groove and can slide relative to the Archimedean spiral disc 410 in the Archimedean spiral groove. The middle portion of the Archimedean spiral disc 410 is connected to the output shaft 440 via a deep groove ball bearing and an elastic washer.

[0075] The upper and lower surfaces of the first lever 420 and the second lever 430 are both provided with linear grooves. The top end of the first fulcrum pivot 330 of the driving mechanism 300 is placed in the linear groove on the lower surface of the first lever 420 and can slide relatively. The top end of the second fulcrum pivot 340 of the driving mechanism 300 is placed in the linear groove on the lower surface of the second lever 430 and can slide relatively.

[0076] Specifically, the variable stiffness principle of the variable stiffness mechanism 400 is to change the rotation of the Archimedean spiral disk 410 into the translation of the first fulcrum pivot 330 and the second fulcrum pivot 340 through the Archimedean spiral groove of the Archimedean spiral disk 410, thereby changing the lever arm length of the first lever 420 and the second lever 430, and thereby changing the transmission ratio between the elastic force and the output torque. It has the advantages of compact structure, fast response, no reverse virtual position, and small error. Theoretically, the stiffness change range can be achieved from 0 to infinity.

[0077] In a specific embodiment, in order to address the coupling phenomenon between the outputs of the joint angle drive motor and the stiffness drive motor of the variable stiffness joint, a solution combining direct drive and rope drive is adopted. As required, a first servo motor and a second servo motor are also included. The first servo motor and the second servo motor are arranged at the rear end of the joint, such as being installed on the arm rod of the robotic arm joint, to reduce the mass and inertia of the end joint of the robotic arm. The rope drive has a simple structure, is easy to manufacture and maintain, and has high reliability; it has a strong load-bearing capacity, and the drive line can be selected with different diameters and materials as needed to meet different load-bearing requirements; it has high transmission efficiency, and the rope drive can improve transmission efficiency by reasonably selecting the drive line material to reduce friction. The rope drive is suitable for low-speed, high-torque transmission occasions and has low noise and vibration.

[0078] Further, refer to Figure 3 The output mechanism 500 includes a first spring pressure plate 510, a first spring 520, a second spring 530, a first spring central shaft 540, a second spring pressure plate 550, a third spring 560, a fourth spring 570, a second spring central shaft 580 and an output disk 590.

[0079] The center hole of the first spring pressure plate 510 passes through and is arranged at the midpoint of the first spring central axis 540. The lower end of the first spring pressure plate 510 is connected to the first lever 420 of the variable stiffness mechanism 400 via an elastic retaining ring. The lower end of the first spring pressure plate 510 is placed in a linear groove on the upper surface of the first lever 420 and can slide relative to the first lever 420. The first spring central axis 540 passes through the center hole of the first spring pressure plate 510 and the first spring pressure plate 510 can slide on the first spring central axis 540. The first spring central axis 540 is arranged horizontally, and the two ends of the first spring central axis 540 are respectively fixed to the inner wall of the output disk 590. The first spring 520 and the second spring 530 are respectively arranged on both sides of the center hole of the first spring pressure plate 510. The two ends of the first spring 520 and the second spring 530 are respectively fixed between the output disk 590 and the center hole of the first spring pressure plate 510 by spring fastening rings.

[0080] The center hole of the second spring pressure plate 550 passes through and is arranged at the midpoint of the second spring central axis 580. The lower end of the second spring pressure plate 550 is connected to the second lever 430 of the variable stiffness mechanism 400 via an elastic retaining ring. The lower end of the second spring pressure plate 550 is placed in a linear groove on the upper surface of the second lever 430 and can slide relative to the second lever 430. The second spring central axis 580 passes through the center hole of the second spring pressure plate 550 and can slide on the second spring central axis 580. The second spring central axis 580 is arranged horizontally, and its two ends are respectively fixed to the inner wall of the output disk 590. The third spring 560 and the fourth spring 570 are respectively arranged on either side of the center hole of the second spring pressure plate 550. The two ends of the third spring 560 and the fourth spring 570 are respectively fixed between the output disk 590 and the center hole of the second spring pressure plate 550 via spring fastening rings.

[0081] Further, refer to Figure 3 The output disc 590 is mounted on the end of the output shaft 440 by means of a nut and a washer. The output disc 590 is fixed in position by a circlip and connected to the output shaft 440 of the variable stiffness mechanism 400 by means of a deep groove ball bearing. The output disc 590 is coaxially arranged with the input shaft 310 of the variable stiffness mechanism 400.

[0082] The central axis of the spring passes horizontally through the hole of the output disk 590 , and both ends of the central axis of the spring are fixed to the output disk 590 by bolts and pressure plates.

[0083] Further, refer to Figures 1 to 3The present invention also proposes a robotic arm, including the compact rope-driven large-range variable stiffness joint based on the lever principle.

[0084] The above description is merely a preferred embodiment of the present invention. The present invention is not limited to the aforementioned embodiments. As long as the technical effects of the present invention are achieved by the same means, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included within the scope of protection of the present disclosure. Within the scope of protection of the present invention, its technical solutions and / or implementation methods may be modified and varied in various ways.

Claims

1. A compact rope-driven wide-range variable stiffness joint based on the lever principle, characterized in that: include: Base module (100); a decoupling mechanism (200), the decoupling mechanism (200) being connected to the base (160) of the base module (100), and the decoupling mechanism (200) being arranged above the base module (100); a driving mechanism (300), the driving mechanism (300) being arranged above the driven wheel (210) of the decoupling mechanism (200); a variable stiffness mechanism (400), the variable stiffness mechanism (400) being arranged above the driving mechanism (300); An output mechanism (500), the output mechanism (500) being placed at the top end of a compact rope-driven large-range variable stiffness joint based on the lever principle, the output mechanism (500) being connected to the variable stiffness mechanism (400); The decoupling mechanism (200) is installed above the base (160) of the base module (100), and comprises a driven wheel (210), a first reversing winding wheel (220), a second reversing winding wheel (230), a coupling rope (240), a stiffness-adjusting driving rope (250), and a direction-changing pulley assembly (260); The driven wheel (210) is arranged above the base (160) of the base module (100), the driven wheel (210) is installed above the base (160) of the base module (100) and is connected to the base (160) through a deep groove ball bearing, the first reversing winding wheel (220) and the second reversing winding wheel (230) are respectively arranged on the side of the driven wheel (210); the upper and lower surfaces of the driven wheel (210) are provided with wire grooves, the coupling rope (240) and the stiffness adjustment driving rope (250) are circumferentially wound in the wire grooves on the upper and lower surfaces of the driven wheel (210), the winding shape of the coupling rope (240) and the stiffness adjustment driving rope (250) is coaxial with the driven wheel (210), and the changing pulley group (260) is arranged above the driven wheel (210); The coupling rope (240) comprises a first coupling rope (241) and a second coupling rope (242). One end of the first coupling rope (241) is fixed to the base (160) of the base module (100), and the other end of the first coupling rope (241) is fixed to the driving disk (320) of the driving mechanism (300); the first coupling rope (241) is wound circumferentially in the grooves on the upper and lower surfaces of the driven wheel (210) through the first reversing winding wheel (220); One end of the second coupling rope (242) is fixed to the base (160) of the base module (100), and the other end of the second coupling rope (242) is fixed to the driving disk (320) of the driving mechanism (300). The second coupling rope (242) is wound circumferentially in the grooves on the upper and lower surfaces of the driven wheel (210) through the second reversing winding wheel (230).

2. The compact rope-driven large-range variable stiffness joint based on the lever principle according to claim 1 is characterized in that: The base module (100) comprises a joint motor (110), a stiffness adjustment motor (120), a stiffness adjustment motor reel (130) connected to an output shaft of the stiffness adjustment motor (120), a motor mounting plate (140), a motor driver mounting plate (150), a base (160), and a base pulley assembly (170). The joint motor (110) and the stiffness adjustment motor (120) are arranged at the rear end of the base (160), the axis of the joint motor (110) and the axis of the stiffness adjustment motor (120) are parallel, and the fixed end of the joint motor (110) and the fixed end of the stiffness adjustment motor (120) are fixed below the motor mounting plate (140) by bolts and are on the same horizontal plane; The motor mounting plate (140) is arranged below the base (160), the motor mounting plate (140) and the base (160) are connected via a copper column, the motor driver mounting plate (150) is installed perpendicular to the motor mounting plate (140) and is fixed to the motor mounting plate (140) via bolts; the motor driver mounting plate (150) is used to drive the joint motor (110) and the stiffness adjustment motor (120) to move; The base pulley assembly (170) is mounted on the lower surface of the base (160) by means of bolts. The base pulley assembly (170) comprises a first high guide pulley (171) and a first low guide pulley (172). The pulley directions of the first high guide pulley (171) and the first low guide pulley (172) are both tangent to the pulley direction of the stiffness adjustment motor winding wheel (130).

3. The compact rope-driven large-range variable stiffness joint based on the lever principle according to claim 2 is characterized in that: The direction-changing pulley assembly (260) includes a second high guide pulley (261) and a second low guide pulley (262); the stiffness-adjusting driving rope (250) includes a first stiffness-adjusting driving rope (251) and a second stiffness-adjusting driving rope (252); One end of the first stiffness adjustment drive rope (251) is wound around and fixed on the stiffness adjustment motor reel (130), and the other end of the first stiffness adjustment drive rope (251) is wound around and fixed on the Archimedean spiral disk (410) of the stiffness variable mechanism (400). The first stiffness adjustment drive rope (251) is wound around the upper and lower surface grooves of the driven wheel (210) through the first reversing reel (220). The first high guide pulley (171) and the second low guide pulley (262) of the base module (100) are used together to guide the first stiffness adjustment drive rope (251) from the stiffness adjustment motor reel (130) of the base module (100) to the Archimedean spiral disk (410) of the stiffness variable mechanism (400). One end of the second stiffness adjustment drive rope (252) is wound around and fixed on the stiffness adjustment motor reel (130), and the winding direction is opposite to that of the first stiffness adjustment drive rope (251); the other end of the second stiffness adjustment drive rope (252) is wound around and fixed on the Archimedean spiral disk (410) of the stiffness variable mechanism (400), and the winding direction is opposite to that of the first stiffness adjustment drive rope (251); the second stiffness adjustment drive rope (252) is wound around the circumference of the upper and lower surface grooves of the driven wheel (210) through the second reversing reel (230); the first low guide pulley (172) and the second high guide pulley (261) of the base module (100) are used together to guide the second stiffness adjustment drive rope (252) from the stiffness adjustment motor reel (130) to the Archimedean spiral disk (410) of the stiffness variable mechanism (400).

4. The compact rope-driven large-range variable stiffness joint based on the lever principle according to claim 2 is characterized in that: The driving mechanism (300) comprises an input shaft (310), a driving disk (320), a first fulcrum pivot (330), and a second fulcrum pivot (340); The output shaft of the joint motor (110) and the central axis of the drive disk (320) are respectively coaxial with the input shaft (310), and the output shaft of the joint motor (110) and the central axis of the drive disk (320) are respectively connected to the input shaft (310); The lower end of the input shaft (310) is connected to the base (160) of the base module (100) via a deep groove ball bearing, the driven wheel (210) of the decoupling mechanism (200) is connected to the input shaft (310) via a deep groove ball bearing, the driving disc (320) is mounted above the driven wheel (210) of the decoupling mechanism (200) via a washer, and the driving disc (320) and the input shaft (310) are fixed via a flat key; The driving disk (320) is provided with a linear slide groove, and the linear slide groove passes through the central axis position of the driving disk (320). The first fulcrum pivot (330) and the second fulcrum pivot (340) are installed on the upper surface of the linear slide groove of the driving disk (320) through plug bolts and bearings and are symmetrically arranged, wherein the bearing is located in the linear slide groove of the driving disk (320) and the movement mode of the bearing is pure rolling motion, so that the first fulcrum pivot (330) and the second fulcrum pivot (340) can slide relative to the driving disk (320).

5. The compact rope-driven large-range variable stiffness joint based on the lever principle according to claim 1 is characterized in that: The variable stiffness mechanism (400) comprises an Archimedean spiral disk (410), a first lever (420), a second lever (430), and an output shaft (440), wherein the first fulcrum pivot (330) of the driving mechanism (300), the second fulcrum pivot (340) of the driving mechanism (300), the Archimedean spiral disk (410), the lever, and the spring pressure plate are stacked; The Archimedes spiral disk (410) is mounted above the driving disk (320) of the driving mechanism (300), the Archimedes spiral disk (410) is connected to the driving disk (320) via a washer, and the Archimedes spiral disk (410) is connected to the input shaft (310) of the driving mechanism (300) via a deep groove ball bearing. An Archimedean spiral groove is provided on the Archimedean spiral disk (410); a first fulcrum pivot (330) and a second fulcrum pivot (340) of the driving mechanism (300) are relatively parallel to the axis of the Archimedean spiral disk (410); the first fulcrum pivot (330) and the second fulcrum pivot (340) of the driving mechanism (300) pass through the Archimedean spiral groove and can slide relative to the Archimedean spiral disk (410) in the Archimedean spiral groove; a middle portion of the Archimedean spiral disk (410) is connected to the output shaft (440) via a deep groove ball bearing and an elastic washer; The upper and lower surfaces of the first lever (420) and the second lever (430) are both provided with linear grooves, the top end of the first fulcrum pivot (330) of the driving mechanism (300) is placed in the linear groove on the lower surface of the first lever (420) and can slide relatively, and the top end of the second fulcrum pivot (340) of the driving mechanism (300) is placed in the linear groove on the lower surface of the second lever (430) and can slide relatively.

6. The compact rope-driven large-range variable stiffness joint based on the lever principle according to claim 2 is characterized in that: The output mechanism (500) includes a first spring pressure plate (510), a first spring (520), a second spring (530), a first spring central shaft (540), a second spring pressure plate (550), a third spring (560), a fourth spring (570), a second spring central shaft (580) and an output disk (590). The center hole of the first spring pressure plate (510) passes through and is set at the midpoint of the first spring center axis (540), and the lower end of the first spring pressure plate (510) is connected to the first lever (420) of the variable stiffness mechanism (400) through an elastic retaining ring; the lower end of the first spring pressure plate (510) is placed in a linear groove on the upper surface of the first lever (420) and can slide relative to the first lever (420); the first spring center axis (540) passes through the center hole of the first spring pressure plate (510), and the first spring pressure plate (510) can Sliding on the first spring center shaft (540); the first spring center shaft (540) is arranged horizontally, and the two ends of the first spring center shaft (540) are respectively fixed on the inner wall of the output disk (590), the first spring (520) and the second spring (530) are respectively arranged on both sides of the center hole of the first spring pressure plate (510), and the two ends of the first spring (520) and the second spring (530) are respectively fixed between the output disk (590) and the center hole of the first spring pressure plate (510) through spring fastening rings; The center hole of the second spring pressure plate (550) passes through and is set at the midpoint of the second spring center axis (580), and the lower end of the second spring pressure plate (550) is connected to the second lever (430) of the variable stiffness mechanism (400) through an elastic retaining ring; the lower end of the second spring pressure plate (550) is placed in a linear groove on the upper surface of the second lever (430) and can slide relative to the second lever (430); the second spring center axis (580) passes through the center hole of the second spring pressure plate (550), and the second spring pressure plate (550) can Sliding on the second spring center shaft (580); the second spring center shaft (580) is arranged horizontally, and the two ends of the second spring center shaft (580) are respectively fixed on the inner wall of the output disk (590), and the third spring (560) and the fourth spring (570) are respectively arranged on both sides of the center hole of the second spring pressure plate (550), and the two ends of the third spring (560) and the fourth spring (570) are respectively fixed between the output disk (590) and the center hole of the second spring pressure plate (550) through spring fastening rings.

7. The compact rope-driven large-range variable stiffness joint based on the lever principle according to claim 6 is characterized in that: The output disc (590) is mounted on the end of the output shaft (440) via a nut and a washer, the output disc (590) is fixed in position via an elastic retaining ring and connected to the output shaft (440) of the variable stiffness mechanism (400) via a deep groove ball bearing, and the output disc (590) is coaxially arranged with the input shaft (310) of the variable stiffness mechanism (400); The second spring center axis (580) passes horizontally through the hole of the output disk (590), and both ends of the second spring center axis (580) are fixed to the output disk (590) by bolts and a pressure plate.

8. A robotic arm, characterized in that: The invention comprises a compact rope-driven large-range variable stiffness joint based on the lever principle as described in any one of claims 1 to 7.

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