Rope-driven mechanical arm with variable-stiffness joint module

Abstract

The invention discloses a rope-driven mechanical arm with a variable-stiffness joint module. The rope-driven mechanical arm comprises a base assembly, a shoulder assembly, a large arm assembly, an elbow assembly, a wrist static platform assembly, a wrist parallel mechanism assembly and a wrist movable platform assembly which are movably connected in sequence. The shoulder assembly comprises three variable stiffness joint modules which are orthogonally connected in sequence; the large arm assembly comprises a plurality of driving assemblies; the robot further comprises a wrist bending driving rope assembly, a wrist yawing bending driving rope assembly, a wrist rotation driving rope assembly and an elbow bending driving rope assembly. The multiple driving assemblies are connected with the wrist bending driving rope assembly, the wrist yaw bending driving rope assembly, the wrist rotation driving rope assembly and the elbow bending driving rope assembly correspondingly. The invention has the beneficial effects of inherent flexibility under the condition of low load and high rigidity under the condition of high load.

Description

Technical Field

[0001] The invention relates to the field of robots, in particular to the field of a rope-driven mechanical arm. Background Art

[0002] In more than half a century of development, the traditional robotic arm has gradually evolved into a highly intelligent and autonomous robotic device with advantages such as high speed, high precision and high efficiency, and has been widely used in various fields. In addition to traditional fields such as manufacturing, medical treatment, national defense and military industry, it has also been gradually applied to emerging fields such as smart home and logistics distribution. The traditional robotic arm is no longer a simple "robotic arm", but an intelligent robot with a variety of intelligent algorithms and advanced control systems. It can complete more complex and diverse tasks, bringing more convenience and benefits to people's lives and work.

[0003] However, most existing robotic arms have rigid joints and are driven by motors, hydraulic cylinders, and pneumatic cylinders, and the driving components are placed at the joints. This not only increases the inertia and weight of the robotic arm, but also makes the robotic arm larger, reduces operational flexibility, and requires a separate working area. In order to solve these problems, a novel driving method is needed to reduce inertia, improve operational flexibility, and meet safety requirements in complex environments.

[0004] Rope drive technology is a driving method based on the transmission of power by rope. Compared with traditional rigid joint manipulators, its biggest feature is that it is light and can be transmitted over long distances. Since rope drive technology places the drive as concentrated as possible on the base and transmits motion and force through ropes, it can effectively reduce the inertia of the manipulator and improve the operational flexibility of the manipulator. At the same time, in order to meet the safety requirements of the manipulator, researchers at home and abroad have proposed connecting elastic elements in series between the driver and the actuator, that is, a series elastic driver. As a member of the elastic driver, the series elastic driver (Series Elastic Actuation, referred to as SEA) is widely used due to its simple structure and good safety. However, at present, variable stiffness series elastic drivers are mostly designed for a specific robot, and there are generally characteristics such as complex system control, low overall joint integration, large flexible joint volume, and insufficient compact installation of joint elements.

[0005] By deeply studying the structure and movement mechanism of the human arm, analyzing the unique biological characteristics, movement characteristics, driving ability and control methods of the human arm, applying the advantages of variable stiffness elastic actuators and rope drive methods to the design of robotic arms, and developing a rope-driven robotic arm with variable stiffness joint modules will have high practical value and realistic significance.

[0006] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art known to a person skilled in the art. Summary of the invention

[0007] The technical problem to be solved by the present invention is: how to solve the problem that the mechanical arm of the current robot cannot satisfy the requirements of having flexibility under low load and having high rigidity under high load.

[0008] The present invention solves the above technical problems through the following technical means:

[0009] A rope-driven mechanical arm with a variable stiffness joint module comprises a base assembly, a shoulder assembly, a large arm assembly, an elbow assembly, a wrist static platform assembly, a wrist parallel mechanism assembly, and a wrist dynamic platform assembly which are movably connected in sequence; the shoulder assembly comprises three variable stiffness joint modules which are orthogonally connected in sequence; the large arm assembly comprises a plurality of drive assemblies;

[0010] It also includes a wrist bending drive rope assembly, wherein the upper arm assembly is connected with the elbow assembly, the wrist static platform assembly, and the wrist dynamic platform assembly through the wrist bending drive rope assembly;

[0011] It also includes a wrist yaw bending drive rope assembly, and the boom assembly is connected to the elbow assembly, the wrist static platform assembly, and the wrist dynamic platform assembly through the wrist yaw bending drive rope assembly;

[0012] It also includes a wrist rotation drive rope assembly, wherein the upper arm assembly is connected with the elbow assembly and the wrist static platform assembly through the wrist rotation drive rope assembly;

[0013] It also includes an elbow bending drive rope assembly, and the upper arm assembly and the elbow assembly are also connected through the elbow bending drive rope assembly;

[0014] The plurality of driving assemblies are respectively connected with the wrist bending driving rope assembly, the wrist yaw bending driving rope assembly, the wrist rotation driving rope assembly, and the elbow bending driving rope assembly.

[0015] The shoulder of the present invention is composed of three variable stiffness joint modules, the elbow is a one-degree-of-freedom rope-driven joint, and the wrist is a three-degree-of-freedom rope-driven joint; the shoulder is composed of orthogonal variable stiffness joint modules, the variable stiffness joint module has passive flexibility, and the stiffness curve increases nonlinearly. It has inherent flexibility under low load conditions and high stiffness under high load conditions.

[0016] Preferably, the shoulder assembly includes a first joint connector, a first variable stiffness joint module, a second joint connector, a second variable stiffness joint module, a third joint connector, a third variable stiffness joint module and a shoulder and upper arm connector which are connected in sequence; the first variable stiffness joint module and the second variable stiffness joint module are axially vertically distributed, and the second variable stiffness joint module and the third variable stiffness joint module are axially vertically distributed.

[0017] Preferably, the boom assembly also includes a first wire wheel fixing plate, a second wire wheel fixing plate, a wrist rotating wire wheel, a wrist bending wire wheel, an elbow wire wheel, and a wrist yaw wheel; the top of the first wire wheel fixing plate and the second wire wheel fixing plate are connected to the shoulder assembly, and the bottom is connected to the elbow assembly; the wrist rotating wire wheel is rotatably connected to the first wire wheel fixing plate, the elbow wire wheel is rotatably connected to the second wire wheel fixing plate, and both ends of the wrist bending wire wheel and the wrist yaw wheel are rotatably connected to the first wire wheel fixing plate and the second wire wheel fixing plate; there are four drive assemblies, which respectively drive the wrist rotating wire wheel, wrist bending wire wheel, elbow wire wheel, and wrist yaw wheel.

[0018] Preferably, the drive assembly includes a motor support frame, a drive motor, a small pulley, a synchronous belt, a large elbow pulley, a large wrist rotating pulley, a large wrist yaw pulley, and a large wrist bending pulley; one of the motor support frames is connected to the first pulley fixing plate, and the other motor support frame is connected to the second pulley fixing plate, the driving end of the drive motor is connected to the small pulley, and the drive motor is connected to the motor support frame; the wrist rotating pulley is connected to the large wrist rotating pulley, the elbow pulley is connected to the large elbow pulley, the wrist bending pulley is connected to the large wrist bending pulley, and the wrist yaw pulley is fixedly connected to the large wrist yaw pulley; the large wrist rotating pulley, the large elbow pulley, the large wrist bending pulley, and the large wrist yaw pulley are respectively connected to the four small pulleys through synchronous belts.

[0019] Preferably, the elbow assembly comprises an upper structure and a lower structure connected in a mirror image, the upper structure is the same as the lower structure, the upper structure comprises two elbow upper end bending pulleys and an elbow upper end left fixing frame, the two elbow upper end bending pulleys are spacedly connected to the elbow upper end left fixing frame; the lower structure comprises two elbow lower end bending pulleys and an elbow lower end left fixing frame, the two elbow lower end bending pulleys are spacedly connected to the elbow lower end left fixing frame, the elbow upper end left fixing frame is rollingly connected to the edge of the elbow lower end left fixing frame;

[0020] The elbow bending drive rope assembly includes an elbow tensioning drive rope and an elbow relaxing drive rope; one end of the elbow tensioning drive rope is fixed and wound around the elbow wire wheel, and the other end is sequentially wound around one of the elbow upper bending pulleys of the upper structure and one of the elbow lower bending pulleys of the lower structure and fixed; one end of the elbow relaxing drive rope is fixed and wound around the elbow wire wheel, and the other end is sequentially wound around another elbow upper bending pulley of the upper structure and another elbow lower bending pulley of the lower structure and fixed.

[0021] Preferably, the upper structure also includes a boom and elbow connecting assembly, a right fixing frame at the upper end of the elbow, and a bent pulley at the upper end of the elbow; the top of the boom and elbow connecting assembly is connected to the boom assembly, the right fixing frame at the upper end of the elbow and the left fixing frame at the upper end of the elbow are fixedly connected to the bottom of the boom and elbow connecting assembly in parallel, two second connecting rods are connected between the right fixing frame at the upper end of the elbow and the left fixing frame at the upper end of the elbow, the bent pulley at the upper end of the elbow is rotatably connected to the first connecting rod, and a plurality of first connecting rods are also connected between the bottom of the boom and elbow connecting assembly and the right fixing frame at the upper end of the elbow and the left fixing frame at the upper end of the elbow, and the bent pulley at the upper end of the elbow is rotatably connected to the first connecting rod.

[0022] Preferably, the wrist static platform assembly includes a base plate changing pulley, a wrist rotation transformation pulley, a wrist base plate, and a base plate inclined pulley group; the wrist base plate is fixedly connected to the bottom of the elbow assembly, the base plate changing pulley is connected to the wrist base plate, the wrist rotation transformation pulley is a cylindrical structure connected to the middle part of the wrist base plate and both ends extend out of the wrist base plate, and the wrist rotation transformation pulley is used to wind and fix the end of the wrist rotation drive rope assembly.

[0023] Preferably, there are four base plate inclined pulley groups, which are respectively connected to the four side surfaces of the wrist base plate; each of the base plate inclined pulley groups includes a base plate rope retainer, a base plate large pulley, and a base plate pulley group frame; the base plate pulley group frame is a rectangular tube structure, and the two sides of the base plate pulley group frame in the length direction can be rotatably connected to the wrist base plate; the base plate rope retainer is a U-shaped frame, which can be stuck on the outside of the base plate pulley group frame, and the base plate rope retainer has an opening, and the wrist bending drive rope assembly and the wrist yaw bending drive rope assembly pass through the hole and are wrapped with the base plate large pulley. The base plate large pulley can be rotatably connected to the base plate pulley group frame.

[0024] Preferably, the wrist parallel mechanism assembly includes a two-degree-of-freedom parallel mechanism and a serial Hooke's hinge assembly, the bottom of the wrist static platform assembly includes a cylindrical structure, the top surface of the wrist dynamic platform assembly includes a cylindrical structure, and the two ends of the two-degree-of-freedom parallel mechanism are respectively fixedly connected to the end surface of the cylindrical structure of the wrist static platform assembly and the end surface of the cylindrical structure of the wrist dynamic platform assembly; the two ends of the serial Hooke's hinge assembly are rotatably connected inside the cylindrical structure of the wrist static platform assembly and the cylindrical structure of the wrist dynamic platform assembly, and the two-degree-of-freedom parallel mechanism is located outside the serial Hooke's hinge assembly.

[0025] Preferably, the wrist moving platform assembly includes a wrist top plate and four top plate inclined pulley blocks; the four sides of the wrist top plate are rotatably connected to the top plate inclined pulley blocks; the top plate inclined pulley blocks include a top plate pulley block frame and a top plate large pulley, the top plate pulley block frame is rotatably connected to the wrist top plate, and the top plate large pulley is rotatably connected to the top plate pulley block frame;

[0026] The wrist bending driving rope assembly includes a wrist bending tensioning driving rope and a wrist bending relaxing driving rope. One end of the wrist bending tensioning driving rope and the wrist bending relaxing driving rope is wound around the wrist bending wire wheel in opposite directions, and the other end is wound around the elbow assembly, the wrist static platform assembly, and the wrist dynamic platform assembly in sequence and then fixed. The elongation and contraction of the rope controls the bending movement of the wrist.

[0027] The wrist yaw bending drive rope assembly includes a wrist yaw tensioning drive rope and a wrist yaw releasing tensioning rope. One end of the wrist yaw tensioning drive rope and the wrist yaw releasing tensioning rope is wound around the wrist yaw wheel in opposite directions, and the other end is wound around the elbow assembly, the wrist static platform assembly, and the wrist dynamic platform assembly in sequence and fixed. The elongation and contraction of the rope controls the yaw movement of the wrist.

[0028] The wrist rotation drive rope assembly includes a first wrist rotation drive rope and a second wrist rotation drive rope; one end of the first wrist rotation drive rope and the second wrist rotation drive rope are both wound around the wrist rotation wheel, and the other end is wound around the wrist rotation transformation wheel; the wrist rotation transformation wheel is used to convert the displacement motion of the first wrist rotation drive rope and the second wrist rotation drive rope into the rotation motion of the wrist.

[0029] The advantages of the present invention are:

[0030] The rope-driven robotic arm with variable stiffness joint modules of the present invention comprises a shoulder composed of three variable stiffness joint modules, an elbow being a one-degree-of-freedom rope-driven joint, and a wrist being a three-degree-of-freedom rope-driven joint; the shoulder is composed of orthogonal variable stiffness joint modules, the variable stiffness joint modules have passive flexibility, a nonlinear increasing stiffness curve, inherent flexibility under low load conditions, and high stiffness under high load conditions.

[0031] The rope-driven manipulator with a variable stiffness joint module of the present invention adopts an equivalent anti-parallelogram mechanism at the elbow, and uses ropes to drive the one-degree-of-freedom movement of the elbow joint. The elbow joint simulates the joint movement of the human elbow, making the rope-driven manipulator elbow more anthropomorphic; at the same time, the rope drive is used to place the drive rear on the upper arm, thereby reducing the inertia. A driving motor is used to drive the tension and relaxation of a pair of ropes in forward and reverse rotation to control the bending and straightening of the elbow.

[0032] The rope-driven manipulator with a variable stiffness joint module of the present invention adopts a spatial two-freedom parallel mechanism at the wrist to realize the simulation of two-degree-of-freedom pure rolling motion between a moving platform and a static platform of the wrist, and four groups of pulley groups are arranged around it to amplify the bending and yaw forces of the wrist, and the wrist is expanded into a three-degree-of-freedom wrist by utilizing the hollow space of the two-degree-of-freedom mechanism and adopting a series Hooke's hinge assembly, and another group of pulley groups are arranged at the bottom of the static platform to convert the displacement of the rope into rotational motion; the wrist simulates the movement of the human wrist, making the rope-driven manipulator wrist more anthropomorphic; and the rope drive is adopted to place the drive rear on the upper arm, thereby reducing the inertia.

[0033] The rope-driven robot arm with a variable stiffness joint module of the present invention adopts rope drive to place the drive at the upper arm, and the drive adopts an outer rotor frameless torque motor and a belt transmission method; the inertia of the end of the rope-driven robot arm is reduced by the rear drive, thereby improving the flexibility of the robot arm and enabling the robot arm to have the ability to move quickly.

[0034] The rope-driven manipulator with a variable stiffness joint module of the present invention has a rope at the wrist that passes through the elbow, so the movement of the elbow will affect the movement of the wrist. Therefore, a pulley arrangement for decoupling the motion of the elbow and wrist is designed at the elbow, which can achieve decoupling of the rope motion of the elbow and wrist, making the rope driving method more precise and the control of the rope-driven manipulator more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a schematic structural diagram of a rope-driven mechanical arm with a variable stiffness joint module according to an embodiment of the present invention;

[0036] Figure 2 is a schematic structural diagram of a rope-driven mechanical arm with a variable stiffness joint module according to an embodiment of the present invention;

[0037] Figure 3 is a schematic structural diagram of a base assembly according to an embodiment of the present invention;

[0038] Figure 4 is a schematic structural diagram of a shoulder assembly according to an embodiment of the present invention;

[0039] Figure 5 is a schematic structural diagram of a shoulder assembly according to an embodiment of the present invention;

[0040] Figure 6 is an exploded schematic diagram of a shoulder assembly according to an embodiment of the present invention;

[0041] Figure 7 is a schematic structural diagram of a boom assembly according to an embodiment of the present invention;

[0042] Figure 8 is a schematic structural diagram of a boom assembly according to an embodiment of the present invention;

[0043] Fig. 9 is a schematic structural diagram of a boom assembly according to an embodiment of the present invention;

[0044] Fig.10 is a front view of a boom assembly according to an embodiment of the present invention;

[0045] Fig.11 yes Fig.10 Sectional view at AA;

[0046] Fig.12 is a schematic structural diagram of an elbow assembly according to an embodiment of the present invention;

[0047] Fig.13 is a schematic structural diagram of an elbow assembly according to an embodiment of the present invention;

[0048] Fig.14 is a schematic structural diagram of an elbow assembly according to an embodiment of the present invention;

[0049] Fig.15 Schematic diagram of the direction of the elbow bending drive rope in an embodiment of the present invention;

[0050] Fig.16 It is a connection diagram of a wrist static platform assembly, a wrist parallel mechanism assembly, and a wrist dynamic platform assembly according to an embodiment of the present invention;

[0051] Fig.17 is an enlarged schematic diagram of a bottom plate inclined pulley block according to an embodiment of the present invention;

[0052] Fig.18 yes Fig.16 A front view of

[0053] Fig.19 yes Fig.18 Sectional view at the middle BB;

[0054] Fig. 20 Schematic diagram of the winding of the wrist static platform assembly and the wrist dynamic platform assembly according to an embodiment of the present invention;

[0055] Fig.21 1 is a schematic structural diagram of a two-degree-of-freedom parallel mechanism of a wrist parallel mechanism assembly according to an embodiment of the present invention;

[0056] Fig. 22 1 is a schematic structural diagram of a serial Hooke's hinge assembly of a wrist parallel mechanism assembly according to an embodiment of the present invention;

[0057] Fig.23 is a schematic structural diagram of a wrist moving platform assembly according to an embodiment of the present invention;

[0058] Fig.24 Schematic diagram of the direction of the wrist bending drive rope according to an embodiment of the present invention;

[0059] Fig.25 Schematic diagram of the direction of the wrist yaw drive rope according to an embodiment of the present invention;

[0060] Fig.26 Schematic diagram of the direction of the wrist rotation drive rope according to an embodiment of the present invention;

[0061] Fig. 27 This is a schematic diagram of the decoupling design of wrist and elbow motion according to an embodiment of the present invention. Figure 1 ;

[0062] Fig.28 This is a schematic diagram of the decoupling design of wrist and elbow motion according to an embodiment of the present invention. Figure 2 ;

[0063] Numbers in the figure:

[0064] 1. Base assembly; 101. Profile base; 102. Base connecting plate; 2. Shoulder assembly; 201. First joint connector; 202. First variable stiffness joint module; 203. Second joint connector; 204. Second variable stiffness joint module; 205. Third joint connector; 206. Third variable stiffness joint module; 207. Shoulder and upper arm connector; 3. Upper arm assembly; 301. Motor support frame; 302. Small pulley housing; 303. Small pulley baffle; 304. Drive motor; 305. Support frame fixing column; 306. Elbow large pulley; 307. Wrist rotating large pulley; 308. Wrist rotating line wheel; 309. Drive Moving rope preload; 310, wrist yaw large pulley; 311, wrist bending large pulley; 312, first line wheel fixing plate; 313, small pulley; 314, wrist bending line wheel; 315, elbow line wheel; 316, wrist yaw line wheel; 317, second line wheel fixing plate; 4, elbow assembly; 401, upper arm and elbow connecting piece; 402, elbow upper connecting tube; 403, elbow upper end baffle; 404, first connecting rod; 405, wrist movement upper end pulley; 406, elbow upper end right fixing frame; 407, elbow upper end left fixing frame; 408, elbow center fixing frame; 409, second connecting rod; 410, elbow upper end bending pulley ; 411, upper pulley of elbow movement; 412, left fixed frame of lower elbow; 413, bending pulley of lower elbow; 414, pulley of lower wrist movement; 5, wrist static platform assembly; 501, bottom plate change pulley; 502, wrist rotation conversion line wheel; 503, wrist bottom plate; 504, bottom plate inclined pulley group; 5041, bottom plate rope holder; 5042, bottom plate large pulley center axis; 5043, bottom plate large pulley; 5044, bottom plate pulley group frame; 5045, bottom plate small pulley; 5046, bottom plate pulley group pin; 5047, bottom plate small pulley center axis; 6, wrist parallel mechanism assembly; 601, two-degree-of-freedom parallel machine Structure; 6011, mechanism top plate; 6012, mechanism upper connecting piece; 6013, mechanism branch; 6014, mechanism lower connecting piece; 6015, mechanism bottom plate; 602, serial Hook's hinge assembly; 6021, first Hook's hinge middle rod; 6022, first Hook's hinge middle rod; 6023, Hook's hinge end connecting piece; 6024, first rotating rod; 6025, second rotating rod; 7, wrist moving platform assembly; 701, wrist top plate; 702, top plate inclined pulley block; 7021, top plate pulley block frame; 7022, top plate large pulley center axis; 7023, top plate rope retainer; 7024, top plate large pulley; 8, palm. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0066] like Figure 1 , Figure 2 As shown, the rope-driven robotic arm with a variable stiffness joint module includes a base assembly 1, a shoulder assembly 2, an upper arm assembly 3, an elbow assembly 4, a wrist static platform assembly 5, a wrist parallel mechanism assembly 6, a wrist dynamic platform assembly 7, and a palm 8 which are connected in sequence.

[0067] like Figure 3 As shown, the base assembly 1 includes a profile base 101 and a base connecting plate 102. The profile base 101 is an aluminum profile, and a base connecting hole 103 is provided on the base connecting plate 102. The base connecting plate 102 is fixed to the profile base 101 through the base connecting hole 103, connecting screws or connecting bolts. The base assembly 1 is to provide an installation position with the shoulder assembly 2.

[0068] like Figure 4 , Figure 5 , Figure 6 As shown, the shoulder assembly 2 includes a first joint connector 201, a first variable stiffness joint module 202, a second joint connector 203, a second variable stiffness joint module 204, a third joint connector 205, a third variable stiffness joint module 206, and a shoulder and upper arm connector 207 connected in sequence. One end of the first joint connector 201 is connected to the first variable stiffness joint module 202, and the other end is connected to the base connecting plate 102. Specifically, the first joint connector 201 is a rectangular plate, and one end connected to the first variable stiffness joint module 202 is arranged in an arc shape. In order to adapt to the surface connection of the first variable stiffness joint module 202, to ensure the connection effect, the first joint connector 201 is connected to the base connecting plate 102 by multiple groups of bolts. The second joint connector 203 includes a circular plate and a vertical plate, the circular plate is vertically connected to the vertical plate, the circular plate is connected to the other end of the first variable stiffness joint module 202, and the vertical plate is connected to the first variable stiffness joint module 202. The third joint connection member 205 includes a circular plate and a bending plate, the bending plate is bent in two 90-degree S-shaped bends, the bending plate is connected to the circular plate, the circular plate is connected to the other end of the second variable stiffness joint module 204, and the other end of the bending plate is connected to one end of the third variable stiffness joint module 206. The other end of the third variable stiffness joint module 206 is connected to the shoulder and upper arm connection member 207. Figure 4As shown, the boom assembly 3 and the shoulder assembly 2 are fixed together by the shoulder and boom connector 207. The shoulder and boom connector 207 includes a rectangular connector plate and four connector columns located on one side of the rectangular connector plate, the four connector columns are connected to the rectangular connector plate at 90 degrees, and four circumferentially distributed hollow grooves are processed on the rectangular connector plate to reduce the weight of the connector.

[0069] The first variable stiffness joint module 202, the second variable stiffness joint module 204, and the third variable stiffness joint module 206 have the same structure. The first variable stiffness joint module 202 and the second variable stiffness joint module 204 are axially vertically distributed, and the second variable stiffness joint module 204 and the third variable stiffness joint module 206 are axially vertically distributed. The shoulder adopts an orthogonal composition of variable stiffness joint modules. The variable stiffness joint module has passive flexibility, and the stiffness curve increases nonlinearly. It has inherent flexibility under low load conditions and high stiffness under high load conditions. The variable stiffness joint module can be realized by using the structure in a compact variable stiffness joint module with flexible elements in CN114800602A.

[0070] like Figure 7 , Figure 8 , Fig. 9 , Fig.10 , Fig.11 As shown, the boom assembly 3 includes two motor support frames 301, four small pulley housings 302, four small pulley baffles 303, four drive motors 304, a support frame fixing column 305, an elbow large pulley 306, a wrist rotating large pulley 307, a wrist rotating line pulley 308, four drive rope pretensioners 309, a wrist yaw large pulley 310, a wrist bending large pulley 311, a first line pulley fixing plate 312, four small pulleys 313, a wrist bending line pulley 314, an elbow line pulley 315, a wrist yaw line pulley 316, and a second line pulley fixing plate 317.

[0071] Two of the connection columns at the bottom of the shoulder and upper arm connection member 207 are respectively connected to the second wire wheel fixing plate 317, and two of the connection columns are respectively connected to the first wire wheel fixing plate 312. The first wire wheel fixing plate 312 and the second wire wheel fixing plate 317 are symmetrically arranged, and a space is formed between them. The bottoms of the first wire wheel fixing plate 312 and the second wire wheel fixing plate 317 are connected to the top of the elbow assembly 4.

[0072] There are two motor support frames 301, each motor support frame 301 is a plate-like structure, wherein the bottom of one motor support frame 301 has two support feet, which can be connected to the first wire wheel fixing plate 312 by bolts, and the bottom of another motor support frame 301 has two support feet, which can be connected to the second wire wheel fixing plate 317. The vertical edges at both ends of the motor support frame 301 form a 90-degree fold to one side, and an elongated hole is provided on the fold, and the side of the small pulley housing 302 is connected to it through the elongated hole by a locking bolt, and the height of the small pulley housing 302 can be adjusted. Each motor support frame 301 also has a waist-shaped hole, and the drive motor 304 is located on one side of the motor support frame 301, and the small pulley housing 302 is located on the other side of the motor support frame 301. The small pulley housing 302 is fixedly connected to the end face of the drive motor 304 and does not rotate with the drive motor 304. The driving end of the drive motor 304 is connected to the small pulley 313. The small pulley baffle plate 303 is encapsulated in the outside of the small pulley housing 302, so that the small pulley 313 is encapsulated in the space surrounded by the small pulley baffle plate 303 and the small pulley housing 302. That is: the drive motor 304 is fixedly connected to the small pulley housing 302, and can move up and down along the elongated hole and the waist-shaped hole. After arriving at the preset position, the locking bolt passes through the elongated hole and the small pulley housing 302 to lock, thereby locking the position of the drive motor 304. Four drive motors 304 drive and connect four small pulleys 313 respectively. The drive motors 304 located on the same motor support frame 301 are arranged in opposite directions. The two drive motors 304 located in the same axial direction are arranged in the same direction.

[0073] The two driving motor support frames 301 are connected with two support frame fixing columns 305 therebetween, thereby increasing the rigidity and improving the strength of the driving motor support frames 301 .

[0074] The wrist rotating pulley 308 is rotatably connected to the first pulley fixing plate 312, and the elbow pulley 315 is rotatably connected to the second pulley fixing plate 317. The wrist rotating pulley 308 and the elbow pulley 315 are axially coaxially arranged; wherein the wrist rotating pulley 308 is also connected to the wrist rotating large pulley 307, and the wrist rotating large pulley 307 is connected to one of the small pulleys 313 through a synchronous belt, so that the drive motor 304 drives the small pulley 313, and transmits the power to the wrist rotating large pulley 307 through the synchronous belt, and the wrist rotating large pulley 307 drives the wrist rotating pulley 308 to rotate, thereby realizing the winding or loosening of the drive rope. Similarly, the elbow pulley 315 is connected to the elbow large pulley 306, and the elbow large pulley 306 is connected to one of the small pulleys 313 through a synchronous belt, so that the drive motor 304 drives the small pulley 313, and transmits the power to the elbow large pulley 306 through the synchronous belt, and the elbow large pulley 306 drives the elbow pulley 315 to rotate, so as to achieve the winding or loosening of the drive rope. The driving wrist rotating pulley 308 and the driving elbow pulley 315 small pulley 313 are located between the two motor support frames 301.

[0075] Both ends of the wrist bending pulley 314 and the wrist yaw pulley 316 are rotatably connected to the first pulley fixing plate 312 and the second pulley fixing plate 317. The wrist bending pulley 314 and the wrist yaw pulley 316 are both located obliquely below the driving wrist rotating pulley 308 and the driving elbow pulley 315. The wrist bending pulley 314 is fixedly connected to the wrist bending large pulley 311, and the wrist bending large pulley 311 is connected to one of the small pulleys 313 through a synchronous belt, so that the driving motor 304 drives the small pulley 313, and transmits it to the wrist bending large pulley 311 through the synchronous belt. The wrist bending large pulley 311 drives the wrist bending pulley 314 to rotate, thereby realizing the winding or loosening of the drive rope. Similarly, the wrist yaw pulley 316 is fixedly connected to the wrist yaw large pulley 310, and the wrist yaw large pulley 310 is connected to one of the small pulleys 313 through a synchronous belt, so that the drive motor 304 drives the small pulley 313, and transmits it to the wrist yaw large pulley 310 through the synchronous belt. The wrist yaw large pulley 310 drives the wrist yaw pulley 316, thereby realizing the winding or loosening of the drive rope.

[0076] In this embodiment, four drive rope pre-tensioners 309 are also included, which are respectively arranged on the wrist rotating wire wheel 308, the wrist bending wire wheel 314, the elbow wire wheel 315 and the wrist yaw wire wheel 316. The drive rope pre-tensioner 309 is an annular structure, and the annular opening can be locked by bolts. The annular structure is sleeved on each wire wheel. A through hole is also provided on the drive rope pre-tensioner 309, and one end of the drive rope is fixed by a rope clamp after passing through the through hole. The drive rope is wound around each wire wheel. Because the joint and the drive are separated, a long drive rope path is required for driving.

[0077] In order to reduce the inertia of the robot arm, four drive motors 304 for the elbow and wrist are placed in the upper arm. Each drive motor 304 has a synchronous belt transmission device, which can achieve an additional reduction ratio of 2.57:1 in addition to the reduction through the tension amplification mechanism. Therefore, the center of gravity of the entire arm moving part is very close to the body. The rope drive can achieve three degrees of freedom of the wrist and one degree of freedom of the elbow.

[0078] like Fig.12 As shown, the elbow assembly 4 is a mirror structure, and the part that can be bent is a symmetric surface. The specific upper structure includes a big arm and elbow connecting piece 401, an elbow upper connecting tube 402, an elbow upper end baffle 403, a first connecting rod 404, a wrist movement upper end pulley 405, an elbow upper end right fixing frame 406, an elbow upper end left fixing frame 407, an elbow center fixing frame 408, a second connecting rod 409, an elbow upper end bending pulley 410, and an elbow movement upper end pulley 411.

[0079] The upper arm and elbow connecting piece 401 is a flat plate, and its bottom surface is connected to the upper elbow connecting tube 402. The upper elbow connecting tube 402 is a cylindrical structure with a square cross section. The bottoms of its two side surfaces are respectively connected to the upper elbow baffle 403. The upper elbow baffle 403 is an inverted triangular plate with a tip at the bottom. The entire upper structure is also symmetrical along the vertical plane. The bottom tips and rear ends of the upper elbow baffles 403 on both sides are respectively connected to the first connecting rod 404. Specifically, the other ends of the two first connecting rods 404a and 404b connected to the right upper elbow baffle 403 pass through and are fixedly connected to the right upper elbow fixing frame 406; the other ends of the two first connecting rods 404c and 404d connected to the upper elbow baffle 403' pass through and are fixedly connected to the left upper elbow fixing frame 407; the first connecting rods 404b and 404d are both connected to the wrist motion upper pulley 405 through bearings. The first connecting rods 404a and 404c are both connected to the upper end pulley 411 of the elbow movement through bearings.

[0080] The right fixing frame 406 and the left fixing frame 407 at the upper end of the elbow have different structures. The right fixing frame 406 at the upper end of the elbow is a triangular frame, the middle part of the bottom side of which is connected to the first connecting rod 404a, and the pointed end corresponding to the bottom side is connected to the first connecting rod 404b; the left fixing frame 407 at the upper end of the elbow is a nearly quadrilateral structure, one side of which is an arc side, which is always in contact with the arc side of the left fixing frame 412 at the lower end of the elbow of the lower structure of the elbow assembly 4, so that the upper structure and the lower structure of the elbow assembly 4 can be bent along the arc side. The center position of the left fixing frame 407 at the upper end of the elbow is connected to the first connecting rod 404d, and the pointed end at the position opposite to the arc side is connected to the first connecting rod 404c.

[0081] The first connecting rod 404b passes through the right fixing frame 406 at the upper end of the elbow and is connected to the right side of the upper end of the central fixing frame 408 of the elbow through a bearing. The first connecting rod 404d passes through the left fixing frame 407 at the upper end of the elbow and is connected to the left side of the upper end of the central fixing frame 408 of the elbow through a bearing.

[0082] A second connecting rod 409 is also connected between the top tip of the right fixing frame 406 at the upper end of the elbow and the top tip of the left fixing frame 407 at the upper end of the elbow, and the two ends are fixedly connected. The bending pulley 410 at the upper end of the elbow is connected to the second connecting rod 409 through a bearing. Fig.13 , Fig.14 As shown, a second connecting rod 409' is connected between the bottom tip of the right fixing frame 406 at the upper end of the elbow and the bottom tip of the left fixing frame 407 at the upper end of the elbow, and the two ends are fixedly connected, and the bending pulley 410' at the upper end of the elbow is connected to the second connecting rod 409' through a bearing.

[0083] The elbow upper bending pulley 410 and the elbow movement upper pulley 411 are used to wind the elbow tensioning driving rope S1 - 1 in the elbow bending driving rope assembly S1 .

[0084] The lower structure is a mirror image of the upper structure and will not be described in detail here. Only important structural parts will be described. The lower structure includes a left fixing frame 412 at the lower end of the elbow, a bending pulley 413 at the lower end of the elbow, and a pulley 414 at the lower end of the wrist movement.

[0085] The left fixing frame 412 at the lower end of the elbow has the same structure as the left fixing frame 407 at the upper end of the elbow, and the arc surfaces of the two are always in contact. The left fixing frame 412 at the lower end of the elbow and the left fixing frame 407 at the upper end of the elbow have two grooves, and ropes are installed in the two grooves to prevent the circular surfaces of the two fixing frames from relative displacement and ensure pure rolling between them. The pulley 414 at the lower end of the wrist movement corresponds to the position of the pulley 405 at the upper end of the wrist movement.

[0086] The single-degree-of-freedom rotation of the elbow uses a drive motor to realize the forward and reverse rotation of the elbow joint. The left fixing frame 412 at the lower end of the elbow and the left fixing frame 407 at the upper end of the elbow ensure that the distance between the upper arm and the lower arm remains unchanged, and at the same time, the rope length between the upper arm and the lower arm can remain unchanged. Fig.14As shown, two wire grooves are designed on the semicircular surface of the left fixing frame 412 at the lower end of the elbow and the left fixing frame 407 at the upper end of the elbow. After the wire grooves of the left fixing frame 412 at the lower end of the elbow and the left fixing frame 407 at the upper end of the elbow are connected, two retaining ropes are built in (as shown by the dotted lines in the figure, the two retaining ropes are arranged crosswise), one end of one retaining rope is fixedly connected to the right bottom end of the left fixing frame 412 at the lower end of the elbow, and the other end is fixed to the left top end of the left fixing frame 407 at the upper end of the elbow along the wire grooves of the left fixing frame 412 at the lower end of the elbow and the left fixing frame 407 at the upper end of the elbow, and the other end is fixed to the left bottom end of the left fixing frame 412 at the lower end of the elbow, and the other end is fixed to the right top end of the left fixing frame 407 at the upper end of the elbow along the wire grooves of the left fixing frame 412 at the lower end of the elbow and the left fixing frame 407 at the upper end of the elbow. The movement of the upper arm and the lower arm is restricted by the two retaining ropes, so that the upper arm and the lower arm are in pure rolling.

[0087] The elbow bending drive rope assembly S1 is a pair of steel wire ropes, including an elbow tensioning drive rope S1-1 and an elbow relaxing drive rope S1-2. One end of the elbow tensioning drive rope S1-1 and the elbow relaxing drive rope S1-2 is fixed by a pre-tightening member 319 and then wound around the elbow wire wheel 315, and the other end is also fixed by a rope clamp. The elbow lower end bending pulley 413 and the elbow upper end bending pulley 410 are a pair, which are used to wind the elbow tensioning drive rope S1-1. The elbow lower end bending pulley 413' and the elbow upper end bending pulley 410' are a pair, which are used to wind the elbow relaxing drive rope S1-2.

[0088] like Fig.15 As shown, the solid line is the elbow tensioning driving rope S1-1, and the dotted line is the elbow relaxing driving rope S1-2. The ends of the elbow tensioning driving rope S1-1 and the elbow relaxing driving rope S1-2 are wound around the elbow wire wheel 315 in opposite directions, and the driving motor drives a pair of ropes to be tensioned and relaxed by positive and negative rotation. When the elbow tensioning driving rope S1-1 contracts, the elbow relaxing driving rope S1-2 stretches, and the elbow produces a bending movement. When the elbow tensioning driving rope S1-1 stretches, the elbow relaxing driving rope S1-2 contracts, and the elbow produces a straightening movement. At the same time, at the elbow, the elbow tensioning driving rope S1-1 and the elbow relaxing driving rope S1-2 adopt a multi-turn rope winding method, and are wound around the upper end pulley 411 of the elbow movement. In this way, the tension of the rope is increased and the load capacity of the elbow is improved.

[0089] like Fig.16 , Fig.18 , Fig.19As shown, the wrist static platform assembly 5 is connected to the bottom of the lower structure of the elbow assembly 4, including a base plate changing pulley 501, a wrist rotation conversion pulley 502, a wrist base plate 503 and a base plate inclined pulley group 504; the wrist base plate 503 is fixedly connected to the bottom of the elbow assembly 4, the base plate changing pulley 501 is connected to the wrist base plate 503 by bolts, and there can be two base plate changing pulleys 501. The wrist rotation conversion pulley 502 is a cylindrical structure, which is located in the middle of the wrist base plate 503 and is connected to the end of the wrist parallel mechanism assembly 6 by screws, and the end close to the elbow assembly 4 is used to wind and fix the end of the wrist rotation drive rope assembly S4.

[0090] There are four bottom plate inclined pulley groups 504, which are respectively located on four sides of the wrist bottom plate 503. Fig.17 As shown, the bottom plate inclined pulley group 504 includes a bottom plate rope retaining frame 5041, a bottom plate large pulley center axis 5042, a bottom plate large pulley 5043, a bottom plate pulley group frame 5044, a bottom plate small pulley 5045, a bottom plate pulley group pin 5046, and a bottom plate small pulley center axis 5047.

[0091] The bottom plate pulley block frame 5044 is a rectangular tube mechanism, and the two sides in the length direction thereof are fixed by the bottom plate pulley block pin 5046, so that the bottom plate pulley block frame 5044 can rotate around the bottom plate pulley block pin 5046. The bottom plate rope holder 5041 is a U-shaped frame, which can be clamped on the outside of the bottom plate pulley block frame 5044. The bottom plate rope holder 5041 has an opening, and the wrist bending drive rope assembly S2 and the wrist yaw bending drive rope assembly S3 can pass through the hole and then be wound around the bottom plate large pulley 5043. The large bottom plate pulley 5043 is located in the bottom plate pulley block frame 5044 and is mounted on the large bottom plate pulley central axis 5042 through bearings and spring retaining rings; the small bottom plate pulley 5045 is also located in the bottom plate pulley block frame 5044 and is located on one side of the large bottom plate pulley 5043. The small bottom plate pulley 5045 is mounted on the small bottom plate pulley central axis 5047 through bearings and spring retaining rings. The wrist bending drive rope assembly S2 and the wrist yaw bending drive rope assembly S3 are mainly wound around the large bottom plate pulley 5043, and the number of rope turns is increased through the small bottom plate pulley 5045.

[0092] like Fig. 20 As shown, the wrist bending drive rope assembly S2 and the wrist yaw bending drive rope assembly S3 are wound between the pulley assembly between the wrist static platform assembly 5 and the wrist dynamic platform assembly 7.

[0093] The wrist bending drive rope assembly S2 includes a pair of steel wire ropes, namely the wrist bending tensioning drive rope S2-1 and the wrist bending relaxation drive rope S2-2, which are a pair of ropes whose ends are wound around the wrist bending wheel 314 in opposite directions. The driving motor moves in positive and reverse directions to drive the extension and contraction of the pair of ropes, thereby controlling the bending movement of the wrist.

[0094] The wrist yaw bending drive rope assembly S3 includes a pair of steel wire ropes, namely the wrist yaw tensioning drive rope S3-1 and the wrist yaw relaxation tensioning rope S3-2, which are a pair of ropes with their ends wound in opposite directions on the wrist yaw wheel 316. The driving motor drives the extension and contraction of the pair of ropes in positive and negative directions to control the yaw movement of the wrist. At the same time, the wrist bending tensioning drive rope S2-1, the wrist bending relaxation drive rope S2-2, the wrist yaw tensioning drive rope S3-1 and the wrist yaw relaxation tensioning rope S3-2 are wound in multiple turns at the wrist to increase the tension of the ropes and improve the load capacity of the wrist.

[0095] The wrist rotation drive rope assembly S4 includes a pair of steel ropes, the ends of the first wrist rotation drive rope S4-1 and the second wrist rotation drive rope S4-4 are both wound around the wrist rotation wheel 308 in opposite directions, and the other ends are wound around the wrist rotation transformation wheel 502; through the wrist rotation transformation wheel 502, the displacement motion of the first and second wrist rotation drive ropes S4-1 and S4-2 are converted into the rotation motion of the wrist.

[0096] like Fig.18 , Fig.19 As shown, the wrist parallel mechanism assembly 6 includes a two-degree-of-freedom parallel mechanism 601 and a serial Hooke's hinge assembly 602; the bottom of the wrist static platform assembly 5 includes a cylindrical structure, and the top surface of the wrist dynamic platform assembly 7 includes a cylindrical structure, and the two ends of the two-degree-of-freedom parallel mechanism 601 are respectively fixedly connected to the end surface of the cylindrical structure of the wrist static platform assembly 5 and the end surface of the cylindrical structure of the wrist dynamic platform assembly 7; the two ends of the serial Hooke's hinge assembly 602 are rotationally connected to the cylindrical structure of the wrist static platform assembly 5 and the cylindrical structure of the wrist dynamic platform assembly 7, and the two-degree-of-freedom parallel mechanism 601 is located outside the serial Hooke's hinge assembly 602.

[0097] like Fig.21 As shown, the two-degree-of-freedom parallel mechanism 601 includes a mechanism top plate 6011, a mechanism upper connecting member 6012, a mechanism branch 6013, a mechanism lower connecting member 6014, and a mechanism bottom plate 6015. The mechanism branch 6013 connects the mechanism top plate 6011 and the mechanism bottom plate 6015 together through the mechanism upper connecting member 6012, the mechanism lower connecting member 6014, and screws, so that the mechanism top plate 6011 and the mechanism bottom plate 6015 simulate a two-degree-of-freedom pure rolling motion.

[0098] like Fig. 22 As shown, the series Hooke's hinge assembly 602 includes a first Hooke's hinge intermediate rod 6021, a second Hooke's hinge intermediate rod 6022, a Hooke's hinge end connector 6023, a first rotating rod 6024, and a second rotating rod 6025; one end of the first Hooke's hinge intermediate rod 6021 and the second Hooke's hinge intermediate rod 6022 are sleeved and fixed together by bolts, wherein the first Hooke's hinge intermediate rod 6021 and the second Hooke's hinge intermediate rod 6022 are provided with radial adjustment holes, and the total length of the first Hooke's hinge intermediate rod 6021 and the second Hooke's hinge intermediate rod 6022 can be adjusted. The other ends of the first Hooke's hinge intermediate rod 6021 and the second Hooke's hinge intermediate rod 6022 are both U-shaped frames, and the two ends of the U-shaped frames are connected to the Hooke's hinge end connector 6023. The two ends of the top Hooke's hinge end connector 6023 are rotatably connected to the first rotating rod 6024, and the two ends of the bottom Hooke's hinge end connector 6023 are rotatably connected to the second rotating rod 6025; the connection between the first rotating rod 6024, the second rotating rod 6025 and the Hooke's hinge end connector 6023 is also a U-shaped frame, and the other end is rod-shaped and connected to the wrist static platform assembly 5 and the wrist dynamic platform assembly 7 through bearings. Also refer to Fig.19 As shown, the outside of the first rotating rod 6024 is connected to the cylindrical structure at the center of the wrist base plate 503 through a bearing, and the top of the first rotating rod 6024 is bolted to the wrist rotation transformation wheel 502; the outside of the second rotating rod 6025 is connected to the wrist moving platform assembly 7 through a bearing.

[0099] like Fig.23 As shown, the wrist moving platform assembly 7 includes a wrist top plate 701 and four top plate inclined pulley blocks 702; the wrist top plate 701 is a rectangular structure, and its four sides are rotatably connected to the top plate inclined pulley blocks 702. Fig.23It can be seen that the center of the wrist moving platform assembly 7 is a cylindrical structure, and there is a bearing inside the cylindrical structure. The end surface of the cylindrical structure is mainly used to connect the two-degree-of-freedom parallel mechanism 601, and the internal bearing is used to connect with the second rotating rod 6025. The top plate inclined pulley group 702 includes a top plate pulley group frame 7021, a top plate large pulley central axis 7022, a top plate rope holder 7023, and a top plate large pulley 7024. There is a notch on each of the four faces of the wrist top plate 701. The top plate pulley group frame 7021 is a rectangular cylinder, and its two ends in the length direction can be rotated through the connecting notches of the pin shaft; the top plate rope holder 7023 is a U-shaped frame, which is clamped on the outside of the top plate pulley group frame 7021 and is fixed after passing through the top plate large pulley central axis 7022; a hole is opened on the end surface of the top plate rope holder 7023, and the rope can pass through the hole and be wound on the top plate large pulley 7024, and can also be used to fix the end of the rope. The top plate pulley 7024 is connected to the top plate pulley central shaft 7022, and the end of the top plate pulley central shaft 7022 is connected to a spring retaining ring to prevent the top plate pulley central shaft 7022 from moving along the axial direction. The top plate pulley 7024 is connected to the top plate pulley central shaft 7022 through a bearing.

[0100] The positions of the four top plate inclined pulley assemblies 702 correspond axially to the positions of the four bottom plate inclined pulley assemblies 504 .

[0101] refer to Fig.24 As shown, the wrist bending driving rope assembly S2 includes a pair of steel wire ropes, namely the wrist bending tension driving rope S2-1 and the wrist bending relaxation driving rope S2-2, which are a pair of ropes with their ends wound around the wrist bending wire wheel 314 in opposite directions. The driving motor drives the extension and contraction of the pair of ropes in positive and negative directions to control the bending movement of the wrist. The middle part of the wrist bending tension driving rope S2-1 can also be wound around the upper end pulley 405 of the wrist movement and the lower end pulley 414 of the wrist movement, and can also be wound around the auxiliary wheel on one side of the bottom plate inclined pulley group 504. The wrist bending tension driving rope S2-1 and the wrist bending relaxation driving rope S2-2 are located between the wrist static platform assembly 5 and the wrist dynamic platform assembly 7, and are wound around the bottom plate large pulley 5043 and the top plate large pulley 7024. The ends can be fixed at the holes of the bottom plate pulley group frame 5044 or the top plate rope retaining frame 7023.

[0102] refer to Fig.25As shown, the wrist yaw bending drive rope assembly S3 includes a pair of steel wire ropes, namely the wrist yaw tensioning drive rope S3-1 and the wrist yaw relaxation tensioning rope S3-2, which are a pair of ropes whose ends are wound around the wrist yaw wheel 316 in opposite directions. The driving motor moves in positive and negative directions to drive the extension and contraction of the pair of ropes, thereby controlling the yaw movement of the wrist. The middle parts of the wrist yaw tensioning drive rope S3-1 and the wrist yaw releasing tensioning rope S3-2 can also be wound around the upper end pulley 405 and the lower end pulley 414 of the wrist movement on the other side, and can also be wound around the auxiliary wheel on one side of the bottom plate inclined pulley group 504; the wrist yaw tensioning drive rope S3-1 and the wrist yaw releasing tensioning rope S3-2 are located between the wrist static platform assembly 5 and the wrist moving platform assembly 7, wound around the bottom plate large pulley 5043 and the top plate large pulley 7024, and the ends can be fixed at the holes of the bottom plate pulley group frame 5044 or the top plate rope retaining frame 7023.

[0103] refer to Fig.26 As shown, the wrist rotation drive rope assembly S4 includes a pair of steel wire ropes, the ends of the first wrist rotation drive rope S4-1 and the second wrist rotation drive rope S4-4 are both wound around the wrist rotation wheel 308 in opposite directions, and the other ends are wound around the wrist rotation transformation wheel 502; through the wrist rotation transformation wheel 502, the displacement motion of the first and second wrist rotation drive ropes S4-1 and S4-2 are converted into the rotation motion of the wrist.

[0104] The rope-driven robotic arm with variable stiffness joint modules of this embodiment has a shoulder composed of three variable stiffness joint modules, an elbow as a one-degree-of-freedom rope-driven joint, and a wrist as a three-degree-of-freedom rope-driven joint; the shoulder is composed of orthogonal variable stiffness joint modules, the variable stiffness joint module has passive flexibility, and the stiffness curve increases nonlinearly. It has inherent flexibility under low load conditions, and high stiffness under high load conditions.

[0105] The rope-driven manipulator with a variable stiffness joint module of this embodiment adopts an equivalent anti-parallelogram mechanism at the elbow, and uses ropes to drive the one-degree-of-freedom movement of the elbow joint. The elbow joint simulates the joint movement of the human elbow, making the rope-driven manipulator elbow more anthropomorphic; at the same time, the rope drive is used to place the drive back on the upper arm, reducing the inertia. A drive motor is used to drive the tension and relaxation of a pair of ropes in forward and reverse rotation to control the bending and straightening of the elbow.

[0106] The rope-driven manipulator with a variable stiffness joint module of this embodiment adopts a spatial two-freedom parallel mechanism at the wrist to realize the simulation of two-degree-of-freedom pure rolling motion between the dynamic platform and the static platform of the wrist, and four groups of pulleys are arranged around it to amplify the bending and yaw forces of the wrist. The hollow space of the two-degree-of-freedom mechanism is utilized, and a series Hooke's hinge assembly 602 is adopted to expand the wrist into a three-degree-of-freedom wrist, and another group of pulleys is arranged at the bottom of the static platform to convert the displacement of the rope into rotational motion; the wrist simulates the movement of the human wrist, making the rope-driven manipulator wrist more anthropomorphic; and the rope drive is used to place the drive rear on the upper arm to reduce the inertia.

[0107] The rope-driven robot arm with a variable stiffness joint module of this embodiment adopts rope drive to place the drive at the upper arm, and the drive adopts an outer rotor frameless torque motor and a belt drive. The rear drive reduces the inertia of the end of the rope-driven robot arm, thereby improving the flexibility of the robot arm and enabling the robot arm to have the ability to move quickly.

[0108] Embodiment three:

[0109] The rope-driven robotic arm with a variable stiffness joint module of this embodiment has a rope that passes through the elbow, so the movement of the elbow will affect the movement of the wrist. Therefore, a pulley arrangement that decouples the motion of the elbow and wrist is designed at the elbow, which can achieve decoupling of the rope motion of the elbow and wrist, making the rope drive method more precise and the control of the rope-driven robotic arm more convenient.

[0110] Specifically, the rope driving the wrist passes through the elbow, so it is necessary to analyze whether the rope length of the wrist changes when the elbow moves. The rope driven by the wrist passes through the elbow joint, and these rope paths will cause coupled motion of the elbow joint. In order to decouple the elbow joint motion and the wrist rope motion, a pulley configuration on the elbow rotation joint is designed, such as Fig. 27 As shown. There are four pulleys, among which the wrist movement upper end pulley 405 and the wrist movement lower end pulley 414 of the upper structure and the lower structure are located on the same axis as the elbow rotation joint. The elbow movement upper end pulley 411 and the elbow movement lower end pulley 415 on both sides are properly placed to maintain a longer rope path. The active rope (solid line) and the antagonistic rope (dotted line) for wrist drive are deployed at the position passing through the wrist movement upper end pulley 405 and the wrist movement lower end pulley 414. The rope point starting from the wrist movement lower end pulley 414 (point a in the figure) and the rope point reaching the wrist movement upper end pulley 405 (point b in the figure) change according to the elbow angle.

[0111] like Fig.28As shown in the figure, assuming that the angle of the elbow joint is θ and the radius of the idle pulley is r, the length of the wire at the starting point increases by r*θ / 2, and the length at the arrival point decreases by r*θ / 2. Therefore, at any angle of the elbow joint, the length of the wire passing through the elbow joint does not change.

[0112] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rope-driven manipulator with a variable stiffness joint module, characterized in that: It includes a base assembly, a shoulder assembly, a big arm assembly, an elbow assembly, a wrist static platform assembly, a wrist parallel mechanism assembly, and a wrist dynamic platform assembly which are movably connected in sequence; the shoulder assembly includes three variable stiffness joint modules which are orthogonally connected in sequence; the big arm assembly includes a plurality of drive assemblies; It also includes a wrist bending drive rope assembly, wherein the upper arm assembly is connected with the elbow assembly, the wrist static platform assembly, and the wrist dynamic platform assembly through the wrist bending drive rope assembly; It also includes a wrist yaw bending drive rope assembly, and the boom assembly is connected to the elbow assembly, the wrist static platform assembly, and the wrist dynamic platform assembly through the wrist yaw bending drive rope assembly; It also includes a wrist rotation drive rope assembly, wherein the upper arm assembly is connected with the elbow assembly and the wrist static platform assembly through the wrist rotation drive rope assembly; It also includes an elbow bending drive rope assembly, and the upper arm assembly and the elbow assembly are also connected through the elbow bending drive rope assembly; The plurality of driving assemblies are respectively connected with the wrist bending driving rope assembly, the wrist yaw bending driving rope assembly, the wrist rotation driving rope assembly, and the elbow bending driving rope assembly.

2. The cable-driven robot arm with a variable stiffness joint module according to claim 1, characterized in that: The shoulder assembly includes a first joint connection member, a first variable stiffness joint module, a second joint connection member, a second variable stiffness joint module, a third joint connection member, a third variable stiffness joint module and a shoulder and upper arm connection member which are connected in sequence; The first variable stiffness joint module and the second variable stiffness joint module are axially and vertically distributed, and the second variable stiffness joint module and the third variable stiffness joint module are axially and vertically distributed.

3. The cable-driven robot arm with a variable stiffness joint module according to claim 1, characterized in that: The boom assembly also includes a first wire wheel fixing plate, a second wire wheel fixing plate, a wrist rotating wire wheel, a wrist bending wire wheel, an elbow wire wheel, and a wrist yaw wheel; the first wire wheel fixing plate and the second wire wheel fixing plate are connected to the shoulder assembly at the top and the elbow assembly at the bottom; the wrist rotating wire wheel is rotatably connected to the first wire wheel fixing plate, the elbow wire wheel is rotatably connected to the second wire wheel fixing plate, and both ends of the wrist bending wire wheel and the wrist yaw wheel are rotatably connected to the first wire wheel fixing plate and the second wire wheel fixing plate; there are four drive assemblies, which respectively drive the wrist rotating wire wheel, wrist bending wire wheel, elbow wire wheel, and wrist yaw wheel.

4. The cable-driven robot arm with a variable stiffness joint module according to claim 3, characterized in that: The driving assembly includes a motor support frame, a driving motor, a small pulley, a synchronous belt, a large pulley for the elbow, a large pulley for wrist rotation, a large pulley for wrist yaw, and a large pulley for wrist bending; One of the motor support frames is connected to the first wire wheel fixing plate, and the other motor support frame is connected to the second wire wheel fixing plate. The driving end of the drive motor is connected to the small pulley, and the drive motor is connected to the motor support frame; the wrist rotating wire wheel is connected to the wrist rotating large pulley, the elbow wire wheel is connected to the elbow large pulley, the wrist bending wire wheel is connected to the wrist bending large pulley, and the wrist yaw wire wheel is fixedly connected to the wrist yaw large pulley; the wrist rotating large pulley, the elbow large pulley, the wrist bending large pulley and the wrist yaw large pulley are respectively connected to the four small pulleys through synchronous belts.

5. The cable-driven robot arm with a variable stiffness joint module according to claim 3, characterized in that: The elbow assembly includes an upper structure and a lower structure connected in a mirror image, the upper structure is the same as the lower structure, the upper structure includes two elbow upper end bending pulleys and an elbow upper end left fixed frame, the two elbow upper end bending pulleys are connected to the elbow upper end left fixed frame at intervals; the lower structure includes two elbow lower end bending pulleys and an elbow lower end left fixed frame, the two elbow lower end bending pulleys are connected to the elbow lower end left fixed frame at intervals, and the elbow upper end left fixed frame is rollingly connected to the edge of the elbow lower end left fixed frame; The elbow bending drive rope assembly includes an elbow tensioning drive rope and an elbow relaxing drive rope; one end of the elbow tensioning drive rope is fixed and wound around the elbow wire wheel, and the other end is sequentially wound around one of the elbow upper bending pulleys of the upper structure and one of the elbow lower bending pulleys of the lower structure and fixed; one end of the elbow relaxing drive rope is fixed and wound around the elbow wire wheel, and the other end is sequentially wound around another elbow upper bending pulley of the upper structure and another elbow lower bending pulley of the lower structure and fixed.

6. The cable-driven robot arm with a variable stiffness joint module according to claim 5, characterized in that: The upper structure also includes a boom and elbow connecting assembly, a right fixing frame at the upper end of the elbow, and a bent pulley at the upper end of the elbow. The top of the boom and elbow connecting assembly is connected to the boom assembly, the right fixing frame at the upper end of the elbow and the left fixing frame at the upper end of the elbow are fixedly connected to the bottom of the boom and elbow connecting assembly in parallel, two second connecting rods are connected between the right fixing frame at the upper end of the elbow and the left fixing frame at the upper end of the elbow, and the bent pulley at the upper end of the elbow is rotatably connected to the first connecting rod, and multiple first connecting rods are also connected between the bottom of the boom and elbow connecting assembly and the right fixing frame at the upper end of the elbow and the left fixing frame at the upper end of the elbow, and the bent pulley at the upper end of the elbow is rotatably connected to the first connecting rod.

7. The cable-driven robot arm with a variable stiffness joint module according to claim 3, characterized in that: The wrist static platform assembly includes a base plate changing pulley, a wrist rotation transformation pulley, a wrist base plate, and a base plate inclined pulley group; the wrist base plate is fixedly connected to the bottom of the elbow assembly, the base plate changing pulley is connected to the wrist base plate, the wrist rotation transformation pulley is a cylindrical structure connected to the middle part of the wrist base plate and both ends extend out of the wrist base plate, and the wrist rotation transformation pulley is used to wind and fix the end of the wrist rotation drive rope assembly.

8. The cable-driven robot arm with a variable stiffness joint module according to claim 7, characterized in that: There are four base plate inclined pulley groups, which are respectively connected to the four side surfaces of the wrist base plate; each of the base plate inclined pulley groups includes a base plate rope retainer, a base plate large pulley, and a base plate pulley group frame; the base plate pulley group frame is a rectangular tube structure, and the two sides of the base plate pulley group frame in the length direction can be rotatably connected to the wrist base plate; the base plate rope retainer is a U-shaped frame, which can be stuck on the outside of the base plate pulley group frame, and the base plate rope retainer has an opening, and the wrist bending drive rope assembly and the wrist yaw bending drive rope assembly pass through the hole and are wrapped with the base plate large pulley. The base plate large pulley can be rotatably connected to the base plate pulley group frame.

9. The cable-driven robot arm with a variable stiffness joint module according to claim 1, characterized in that: The wrist parallel mechanism assembly includes a two-degree-of-freedom parallel mechanism and a serial Hooke's hinge assembly. The bottom of the wrist static platform assembly includes a cylindrical structure, and the top surface of the wrist dynamic platform assembly includes a cylindrical structure. The two ends of the two-degree-of-freedom parallel mechanism are respectively fixedly connected to the end surface of the cylindrical structure of the wrist static platform assembly and the end surface of the cylindrical structure of the wrist dynamic platform assembly; the two ends of the serial Hooke's hinge assembly are rotatably connected in the cylindrical structure of the wrist static platform assembly and the cylindrical structure of the wrist dynamic platform assembly, and the two-degree-of-freedom parallel mechanism is located outside the serial Hooke's hinge assembly.

10. The cable-driven robot arm with a variable stiffness joint module according to claim 8, characterized in that: The wrist moving platform assembly includes a wrist top plate and four top plate inclined pulley blocks; the four sides of the wrist top plate are rotatably connected to the top plate inclined pulley blocks; the top plate inclined pulley blocks include a top plate pulley block frame and a top plate large pulley, the top plate pulley block frame is rotatably connected to the wrist top plate, and the top plate large pulley is rotatably connected to the top plate pulley block frame; The wrist bending driving rope assembly includes a wrist bending tensioning driving rope and a wrist bending relaxing driving rope. One end of the wrist bending tensioning driving rope and the wrist bending relaxing driving rope is wound around the wrist bending wire wheel in opposite directions, and the other end is wound around the elbow assembly, the wrist static platform assembly, and the wrist dynamic platform assembly in sequence and then fixed. The elongation and contraction of the rope controls the bending movement of the wrist. The wrist yaw bending drive rope assembly includes a wrist yaw tensioning drive rope and a wrist yaw releasing tensioning rope. One end of the wrist yaw tensioning drive rope and the wrist yaw releasing tensioning rope is wound around the wrist yaw wheel in opposite directions, and the other end is wound around the elbow assembly, the wrist static platform assembly, and the wrist dynamic platform assembly in sequence and fixed. The elongation and contraction of the rope controls the yaw movement of the wrist. The wrist rotation drive rope assembly includes a first wrist rotation drive rope and a second wrist rotation drive rope; one end of the first wrist rotation drive rope and the second wrist rotation drive rope are both wound around the wrist rotation wheel, and the other end is wound around the wrist rotation transformation wheel; the wrist rotation transformation wheel is used to convert the displacement motion of the first wrist rotation drive rope and the second wrist rotation drive rope into the rotation motion of the wrist.

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