Multi-degree-of-freedom self-tensioning rope-driven robotic arm

Abstract

The application discloses a multi-degree-of-freedom self-tensioning rope-driven mechanical arm. The self-tensioning rope-driven mechanical arm adopts a single rope to pull the joint movement of the mechanical arm, ingeniously configures the rope path and the winding direction of the rope, comprehensively utilizes the gravity and the spring force to keep all the driving ropes in tension, and utilizes the elastic potential energy stored by the spring to compensate the elongation of the rope in the operation process. Compared with the mechanical arm adopting two ropes for bidirectional traction in the prior art, the self-tensioning rope-driven mechanical arm of the application utilizes a spring to maintain the tension of all the ropes, does not need to set a tensioning device for each driving rope, can compensate the linear elongation of the rope in the operation process, and has the advantages of simple structure and high operation efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of multi-joint robot arm, in particular to a multi-degree-of-freedom series robot arm with concentrated arrangement of drivers and rope drive. BACKGROUND

[0002] At present, most of the multi-degree-of-freedom series electric drive robot arms have driving motors placed near the joints. The driving motors are often heavy, and the motors placed near the joints can be regarded as the load of the robot arm. The unnecessary energy consumption is caused by lifting the motor of the robot arm. When the multi-degree-of-freedom series electric drive robot arm is used for underwater operation, the motor placed at the joint also faces the problem of waterproof sealing. The use of a large amount of sealing pressure-resistant materials leads to a large volume, a large mass and a large moment of inertia of the robot arm, which weakens the operation performance of the underwater electric drive robot arm and causes great interference to the underwater body. In order to overcome the shortcomings of the traditional robot arm, some documents propose a multi-degree-of-freedom series robot arm with rope drive. The rope can easily transmit force along an irregular path, so that the design idea of placing all driving motors of the robot arm at the base and transmitting power by the rope can be realized. After the driving motors are placed at the base, the mass of the arm body part of the robot arm is greatly reduced, the energy consumption caused by lifting the motor of the robot arm is eliminated, and the operation energy consumption ratio of the robot arm is improved. For the underwater robot arm, the waterproof sealing problem of the driving motor of the robot arm can be eliminated by placing the driving motor of the robot arm at the base, so that the robot arm can be designed in a hollow form and the water resistance of the robot arm during movement is obviously reduced.

[0003] Some rope-driven robot arms are designed in the prior art, which can be divided into two categories according to whether the main material of the robot arm is flexible or rigid, i.e. rope-driven flexible robot arm and rigid rope-driven robot arm. The rope-driven flexible robot arm is suitable for medical field and is not suitable for industrial production and load operation task. However, the existing rigid rope-driven robot arm still has some shortcomings when applied to production and operation.

[0004] For example, Wu Zhiwei et al. designed a 7-DOF rope-driven humanoid robot arm, which imitates human movement and uses more pulley guide devices, and is not suitable for industrial production operations

Wu Zhiwei, Wang Bowen, Yan Lei, et al. Design of 7-DOF rope-driven humanoid robot arm and its stiffness modeling and performance analysis [J]. Journal of Mechanical Engineering, 2023, 59(17): 17-32.

Wang Xu, Chen Naijian, Wang Chao, et al. Structure design of rope transmission mechanical arm for old and disabled wheelchair [J]. Journal of Jinan University (Natural Science Edition), 2020, 34(03): 300-305.

[0005] The above research results achieve the basic functions of rope-driven mechanical arms, and achieve the design goal of using ropes to transmit power and reducing the weight of the mechanical arm. To further improve the work performance of rope-driven mechanical arms and widely apply them to industrial production and actual work, further optimization design, simplification of structure, and solution of the problem of rope slackening are needed. SUMMARY

[0006] To solve the above problems, the present application provides a multi-DOF self-tensioning rope-driven mechanical arm that can tension all driving ropes without setting tensioning devices for each driving rope, compensate for the linear elongation of the rope under stress during operation, and has the advantages of simple structure and high work efficiency.

[0007] To achieve the above object, the present application adopts the following technical solutions:

[0008] A multi-degree-of-freedom self-tensioning rope-driven mechanical arm, comprising a base, a waist unit extending downward from the base, a large-arm unit hingedly connected to the waist unit, a small-arm unit hingedly connected to the large-arm unit, and an end unit hingedly connected to the small-arm unit; further comprising a large-arm driving unit, a small-arm driving unit, and an end driving unit; characterized in that the large-arm unit is hingedly connected to the waist unit through a large-arm rotating shaft, and a coaxial large-arm joint driving wheel, a right large-arm joint guide wheel, and a left large-arm joint guide wheel are arranged on the large-arm rotating shaft; the large-arm unit is further provided with a large-arm joint support shaft arranged downstream of the large-arm rotating shaft and parallel to the large-arm rotating shaft, and a left large-arm guide wheel and a right large-arm guide wheel are arranged on the large-arm joint support shaft; the small-arm unit is hingedly connected to the large-arm unit through a small-arm rotating shaft, and a coaxial small-arm joint driving wheel and a small-arm joint guide wheel are arranged on the small-arm rotating shaft; the small-arm unit is further provided with a small-arm guide wheel shaft arranged downstream of the small-arm rotating shaft and parallel to the small-arm rotating shaft, and a small-arm guide wheel is arranged on the small-arm guide wheel shaft; the end driving unit is hingedly connected to the small-arm unit through an end rotating shaft, and a coaxial end driving wheel and a tensioning wheel are arranged on the end rotating shaft; a tensioning rope is fixed on the tensioning wheel, and one end of the tensioning rope extending out of the tensioning wheel provides a tensioning force for the tensioning wheel and the end driving wheel through a tensioning spring;

[0009] The large-arm driving unit, the small-arm driving unit, and the end driving unit are all rope driving units; the large-arm driving unit has a large-arm driving rope, the end of which is wound and fixed with the large-arm joint driving wheel; the small-arm driving unit has a small-arm driving rope, the end of which is wound and fixed with the small-arm joint driving wheel after passing through the right large-arm joint guide wheel and the right large-arm guide wheel in sequence; the end driving unit has an end driving rope, the end of which is wound and fixed with the end driving wheel after passing through the left large-arm joint guide wheel, the left large-arm guide wheel, the small-arm joint guide wheel, and the small-arm guide wheel in sequence; the portions of the small-arm driving rope and the end driving rope between the large-arm rotating shaft and the small-arm rotating shaft are arranged in one or more "8" shapes, and the tangent points of the small-arm driving rope on the right large-arm joint guide wheel and the tangent points of the large-arm driving rope on the large-arm joint driving wheel are respectively located on the two sides of the large-arm rotating shaft; the tangent points of the end driving rope on the small-arm joint guide wheel and the tangent points of the small-arm driving rope on the small-arm joint driving wheel are respectively located on the two sides of the small-arm rotating shaft.

[0010] Further, the end driving rope is used to rotate the end unit clockwise, the small arm driving rope is used to rotate the small arm unit clockwise, and the large arm driving rope is used to rotate the large arm unit clockwise; the tension spring pulls the tension rope, so that the end unit has a tendency to rotate counterclockwise to tighten the end driving rope; the end driving rope pulls the small arm unit, so that the small arm unit has a tendency to rotate clockwise to tighten the small arm driving rope; the small arm driving rope pulls the large arm unit, so that the large arm unit has a tendency to rotate clockwise to tighten the large arm driving rope.

[0011] Alternatively, the end driving rope is used to rotate the end unit counterclockwise, the small arm driving rope is used to rotate the small arm unit counterclockwise, and the large arm driving rope is used to rotate the large arm unit counterclockwise; the tension spring pulls the tension rope, so that the end unit has a tendency to rotate clockwise to tighten the end driving rope; the end driving rope pulls the small arm unit, so that the small arm unit has a tendency to rotate counterclockwise to tighten the small arm driving rope; the small arm driving rope pulls the large arm unit, so that the large arm unit has a tendency to rotate counterclockwise to tighten the large arm driving rope.

[0012] Further, when the rope-driven mechanical arm is applied to an underwater environment, the large arm driving unit, the small arm driving unit and the end driving unit all adopt waterproof motors, and the waterproof motors are placed inside the underwater carrier.

[0013] Further, the large arm driving unit, the small arm driving unit and the end driving unit are all mounted on the base.

[0014] Further, the small arm guide wheel shaft is provided with a plurality of S-shaped arrangements of the small arm driving rope between the small arm rotating shaft and the end rotating shaft.

[0015] Further, one end of the tension spring is connected and fixed with the tension rope, and the other end of the tension spring is fixed on one small arm guide wheel shaft.

[0016] Further, the motor brake of the large arm driving unit, the small arm driving unit and the end driving unit realizes rope tensioning.

[0017] Further, the motor driving wheel of the large arm driving unit and the large arm joint driving wheel center symmetry line are kept in the same plane; the motor driving wheel of the small arm driving unit and the large arm joint guide wheel, the large arm guide wheel and the small arm driving wheel center symmetry line are kept in the same plane; the motor driving wheel of the end driving unit and the large arm guide wheel, the small arm joint guide wheel, the small arm guide wheel and the end driving wheel center symmetry line are kept in the same plane.

[0018] Further, by adjusting the tension of the tension spring, a suitable tension preload is set, and the length change of the tension spring is used to realize free rotation of the end unit posture.

[0019] Further, it is applied to the seabed and land.

[0020] Further, the arm body of the mechanical arm is a hollow structure, and the guide wheel shaft adopts a pipe sleeve structure.

[0021] Beneficial effects: In the application, the rope path and the rope winding direction are ingeniously configured, the gravity and the spring force are comprehensively utilized to keep all the driving ropes in tension, and the elastic potential energy stored by the spring is utilized to compensate the elongation of the ropes during operation. Compared with the mechanical arm in the prior art which adopts two ropes for bidirectional traction, the self-tensioning rope-driven mechanical arm in the application uses one spring to maintain the tension of all the ropes, does not need to set a tensioning device for each driving rope, can compensate the linear elongation of the ropes during operation, and has the advantages of simple structure and high operation efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Internal structure diagram of the rope-driven underwater mechanical arm after removing the support plate on one side;

[0023] Figure 2 Axonometric view of the rope-driven underwater mechanical arm;

[0024] Figure 3 Oblique top view of the rope-driven underwater mechanical arm;

[0025] Figure 4 Three-dimensional exploded view of the driving motor unit;

[0026] Figure 5 Front view of the driving part;

[0027] Figure 6 Top view of the driving part;

[0028] Figure 7 Overall structure diagram of the large arm unit;

[0029] Figure 8 Exploded view of the large arm unit;

[0030] Figure 9 Overall structure diagram of the small arm unit;

[0031] Figure 10 Side view of the small arm unit;

[0032] Figure 11 Overall structure diagram of the gripper part;

[0033] Figure 12 Arrangement diagram of all the ropes of the mechanical arm;

[0034] Figure 13 Large arm driving mode diagram showing only the large arm driving ropes;

[0035] Figure 14Schematic diagram of small arm driving mode for presenting only small arm driving rope

[0036] Figure 15 Schematic diagram of end driving mode and tensioning mode

[0037] Figure 16 Schematic diagram of position of tensioning device

[0038] Figure 17 Schematic diagram of rope arrangement of underwater carrier-robot arm system

[0039] Figure 18 Axonometric view of overall structure of underwater carrier-robot arm system

[0040] Figure 19 Schematic diagram of land application robot arm

[0041] Figure 20 Front view of land application robot arm

[0042] Figure 21 Large arm driving motion profile diagram for land application

[0043] Figure 22 Small arm driving motion profile diagram for land application

[0044] Figure 23 End driving motion profile diagram for land application

[0045] Figure label name: 1 base plate, 2 waist unit, 3 large arm driving unit, 4 small arm driving unit, 5 end driving unit, 6 large arm unit, 7 large arm joint driving wheel, 8 large arm joint guide wheel, 9 large arm guide wheel, 10 small arm unit, 11 small arm joint driving wheel, 12 small arm joint guide wheel, 13 small arm guide wheel, 14 end unit, 15 end driving wheel, 16 mechanical gripper, 17 tensioning wheel, 18 large arm driving rope, 19 small arm driving rope, 20 end driving rope, 21 tensioning mechanism, 22 large arm guide wheel shaft, 23 small arm guide wheel shaft, 24 underwater carrier shell, 25 propeller

[0046] 201 joint right connecting rod, 202 joint left connecting rod

[0047] 301 T-shaped single bearing seat, 302 deep groove ball bearing, 303 shaft elastic retainer, 304 motor driving wheel shaft, 305 motor driving wheel, 306 plum blossom coupling, 307 M3 round head screw, 308 key, 309 motor support, 310 driving motor

[0048] 4, 5 have the same structure as 3

[0049] 601 left big arm plate, 602 right big arm plate, 603 left big arm plate sleeve, 604 right big arm plate sleeve, 605 big arm rotating shaft, 606 big arm joint support shaft, 607 M5 inner hexagonal head screw, 608 M5 nut, 609 M5 thin nut;

[0050] 801 right big arm joint guide wheel, 802 left big arm joint guide wheel;

[0051] 901-1 right big arm guide wheel, 901-2 right big arm guide wheel, 902-1 left big arm guide wheel, 902-2 left big arm guide wheel;

[0052] 1001 left small arm plate, 1002 right small arm plate, 1003 left small arm plate sleeve, 1004 right small arm plate sleeve, 1005 small arm rotating shaft, 1006 small arm joint support shaft, 1007 M5 inner hexagonal head screw, 1008 M5 nut, 1009 M5 thin nut;

[0053] 1401 end support top plate, 1402 end support left side plate, 1403 end right side plate, 1404 end rotating shaft, 1405 M3 round head screw;

[0054] 2101 tensioning rope, 2102 tensioning spring, 2103 tensioning wheel;

[0055] 2201 sleeve, 2202 sleeve, 2203 sleeve, 2204 sleeve, 2205 sleeve, 2206 sleeve, 2207 sleeve, 2208 sleeve, 2209 sleeve, 2210 sleeve, 2211 sleeve, 2212 sleeve. DETAILED DESCRIPTION

[0056] Example one, application of rope-driven mechanical arm on underwater carrier

[0057] The application will be further described below with reference to the drawings.

[0058] Reference Figure 1 , Figure 2 and Figure 3As shown, the application discloses a rope-driven multi-degree-of-freedom series-connected mechanical arm, which comprises a base bottom plate 1, a waist unit 2, a large-arm driving unit 3, a small-arm driving unit 4, a terminal driving unit 5, a large-arm unit 6, a large-arm joint driving wheel 7, a large-arm joint guide wheel 8, a large-arm guide wheel 9, a small-arm unit 10, a small-arm joint driving wheel 11, a small-arm joint guide wheel 12, a small-arm guide wheel 13, a terminal unit 14, a terminal driving wheel 15, a mechanical gripper 16, a tensioning wheel 17, a large-arm driving rope 18, a small-arm driving rope 19, a terminal driving rope 20, a tensioning mechanism 21, a large-arm guide wheel shaft 22 and a small-arm guide wheel shaft 23. The large-arm unit 6, the small-arm unit 10 and the terminal unit 14 are three parallel rotation degrees of freedom which are perpendicular to the waist unit 2. The large-arm driving unit 5, the small-arm driving unit 4 and the terminal driving unit 6 are all mounted on the base bottom plate 1. The large-arm driving rope 18 connects the large-arm driving unit 3 and the large-arm joint driving wheel 7; the small-arm driving rope 19 connects the small-arm driving unit 4, the right large-arm joint guide wheel 801, the right large-arm guide wheel 901-1, the right large-arm guide wheel 901-2 and the small-arm driving wheel 11; and the terminal driving rope 20 connects the terminal driving unit 5, the left large-arm joint guide wheel 802, the left large-arm guide wheel 902-1, the left large-arm guide wheel 902-2, the small-arm joint guide wheel 12, the small-arm guide wheel 13 and the terminal driving wheel 15. The small-arm driving unit 4 and the terminal driving unit 5 are used for tensioning the large-arm unit 6 and the small-arm unit 10 through the small-arm driving rope 19 and the terminal driving rope 20, and the motors of the large-arm driving unit 3, the small-arm driving unit 4 and the terminal driving unit 5 are used for realizing tension pre-tightening. The tensioning mechanism 21 is used for tensioning the terminal unit 14, and the motor of the terminal driving unit 5 can limit the movement of the terminal driving rope 20. Through reasonable configuration of the winding directions of the ropes on the large-arm joint driving wheel 7 and the small-arm joint driving wheel 11, the mechanical coupling characteristics of the rope-driven mechanical arm can be utilized, so that the tensioning mechanism 21 can transmit the tension to the small-arm unit 10 and the large-arm unit 6 while tensioning the terminal unit 14. The tension transmitted to the small-arm unit 10 through the tensioning mechanism and the driving force of the small-arm driving unit 4 can realize the tensioning of the small-arm driving rope 19; and the tension transmitted to the large-arm unit 6 through the tensioning mechanism and the driving force of the large-arm driving unit 3 can realize the tensioning of the large-arm driving rope 18. During operation, the joint ropes transmit driving forces to drive the joint shafts to rotate, so as to form the rope-driven multi-degree-of-freedom series-connected mechanical arm, and the ropes are always kept in a tensioned state; and the spring can compensate the elongation of the ropes and the deformation of the mechanism during operation, so as to effectively avoid the problem of rope slackening during the operation of the rope-driven mechanical arm.

[0059] Refer to Figure 1 , Figure 2 and Figure 3As shown in the figure, the motor drive wheel of the upper arm driving unit 3 and the center symmetry line of the upper arm joint driving wheel 7 are kept in the same plane; the motor drive wheel of the lower arm driving unit 4 and the center symmetry line of the right upper arm joint guide wheel 801, the right upper arm guide wheel 901-1, the right upper arm guide wheel 901-2 and the lower arm driving wheel 11 are kept in the same plane; the motor drive wheel of the end driving unit 5 and the center symmetry line of the left upper arm joint guide wheel 802, the right upper arm guide wheel 902-1, the left upper arm guide wheel 902-2, the lower arm joint guide wheel 12, the lower arm guide wheel 13 and the end driving wheel 15 are kept in the same plane; the tensioning mechanism 21 exerts tensioning force on the end unit 14 through the spring action force.

[0060] As shown in the figure, Figure 1 , Figure 2 and Figure 3 , the driving mode of each joint of the rope-driven multi-degree-of-freedom serial manipulator is as follows: the upper arm driving rope 18 connects the upper arm driving unit 3 and the upper arm joint driving wheel 7, the motor drive wheel in the upper arm driving unit 3 winds the rope to drive the upper arm joint driving wheel 7 to rotate, the upper arm joint driving wheel 7 is connected with the joint shaft of the upper arm unit 6 to drive the upper arm unit 6 to rotate around the shaft and drive the upper arm joint to move; the lower arm driving rope 19 connects the lower arm driving unit 4, the right upper arm joint guide wheel 801, the right upper arm guide wheel 901-1, the right upper arm guide wheel 901-2 and the lower arm driving wheel 11, the motor drive wheel of the lower arm driving unit 4 winds the rope, which is guided through the right upper arm joint guide wheel 801, the right upper arm guide wheel 901-1 and the right upper arm guide wheel 901-2, to drive the lower arm driving wheel 11 to rotate, the lower arm driving wheel 11 is connected with the joint shaft of the lower arm unit 10 to drive the lower arm unit 10 to rotate around the shaft and drive the lower arm joint to move; the end driving rope 20 connects the end driving unit 5, the left upper arm joint guide wheel 802, the left upper arm guide wheel 902-1, the left upper arm guide wheel 902-2, the lower arm joint guide wheel 12, the lower arm guide wheel 13 and the end driving wheel 15. The motor drive wheel of the end driving unit 5 winds the rope, which is guided through the left upper arm joint guide wheel 802, the left upper arm guide wheel 902-1, the left upper arm guide wheel 902-2, the lower arm joint guide wheel 12 and the lower arm guide wheel 13, to drive the end driving wheel 15 to rotate, the end driving wheel 15 is connected with the joint shaft of the end unit 14 to drive the end unit 14 to rotate around the shaft and drive the end joint to move.

[0061] As shown in the figure, Figure 1 , the rope-driven multi-degree-of-freedom serial manipulator can use one spring to tension all the driving ropes of the manipulator, and the specific tensioning principle is as follows: from Figure 1From the perspective of the end effector, the end driving rope 20 is used to rotate the end unit 14 clockwise, the small arm driving rope 19 is used to rotate the small arm unit 10 clockwise, and the large arm driving rope 18 is used to rotate the large arm unit 6 clockwise; the tension spring 2102 pulls the tension rope 2101, so that the end unit 14 has a tendency to rotate counterclockwise, thereby tensioning the end driving rope 20; the end driving rope 20 pulls the small arm unit 10, so that the small arm unit 10 has a tendency to rotate counterclockwise, thereby tensioning the small arm driving rope 19; the small arm driving rope 19 pulls the large arm unit 6, so that the large arm unit 6 has a tendency to rotate counterclockwise, thereby tensioning the large arm driving rope 18. Therefore, the large arm driving rope 18, the small arm driving rope 19 and the end driving rope 20 are all tensioned by the tension spring 2102, that is, the design goal of tensioning all the driving ropes of a single spring tensioning robot arm is achieved. It should be pointed out that the "clockwise" and "counterclockwise" here are described from the perspective of the end effector, and the description of the direction of "clockwise" and "counterclockwise" will also be changed when the perspective is changed, which will not be described here. Figure 1

[0062] Referring to FIG. 1, the waist unit 2 includes a base bottom plate 1, a large arm driving unit 3, a small arm driving unit 4, an end driving unit 5, a joint right connecting rod 201, and a joint left connecting rod 202. The large arm driving unit 3, the small arm driving unit 4, and the end driving unit 5 are installed on the upper side of the base bottom plate 1 by screws; the joint right connecting rod 201 and the joint left connecting rod 202 are installed on the lower side of the base bottom plate 1 by screws. Figure 4

[0063] Referring to FIG. 1, the waist unit 2 includes a base bottom plate 1, a large arm driving unit 3, a small arm driving unit 4, an end driving unit 5, a joint right connecting rod 201, and a joint left connecting rod 202. The large arm driving unit 3, the small arm driving unit 4, and the end driving unit 5 are installed on the upper side of the base bottom plate 1 by screws; the joint right connecting rod 201 and the joint left connecting rod 202 are installed on the lower side of the base bottom plate 1 by screws. Figure 5 Figure 6 Referring to FIG. 1, the waist unit 2 includes a base bottom plate 1, a large arm driving unit 3, a small arm driving unit 4, an end driving unit 5, a joint right connecting rod 201, and a joint left connecting rod 202. The large arm driving unit 3, the small arm driving unit 4, and the end driving unit 5 are installed on the upper side of the base bottom plate 1 by screws; the joint right connecting rod 201 and the joint left connecting rod 202 are installed on the lower side of the base bottom plate 1 by screws.

[0064] Referring to FIG. 1, the waist unit 2 includes a base bottom plate 1, a large arm driving unit 3, a small arm driving unit 4, an end driving unit 5, a joint right connecting rod 201, and a joint left connecting rod 202. The large arm driving unit 3, the small arm driving unit 4, and the end driving unit 5 are installed on the upper side of the base bottom plate 1 by screws; the joint right connecting rod 201 and the joint left connecting rod 202 are installed on the lower side of the base bottom plate 1 by screws. Figure 7 Figure 8 ​​​​As shown, the arm unit 6 includes a left arm plate 601, a right arm plate 602, a left arm plate sleeve 603, a right arm plate sleeve 604, an arm rotating shaft 605, an arm joint support shaft 606, an arm joint driving wheel 7, an arm joint guide wheel 8, and an arm guide wheel 9. The lower end holes of the left arm plate sleeve 603 and the right arm plate sleeve 604 are machined with key grooves and pin holes, which are connected with the shaft hole of the arm rotating shaft 605 through keys and pins to increase the driving performance. The left arm plate sleeve 603 and the right arm plate sleeve 604 are fixed with the left arm plate 601 and the right arm plate 602 through M5 inner hexagonal cylindrical head screws 607, M5 nuts 608, and M5 thin nuts 609, and are connected with the arm rotating shaft 605 through keys. After the installation and compression of each component, the joint right connecting rod 201 and the joint left connecting rod 202 compress the arm rotating shaft 605 as axial fixation. The arm rotating shaft 605 is machined with key holes, and the arm joint driving wheel 7 is connected with the arm rotating shaft 605 through keys to drive the arm. The arm joint guide wheel 8 is installed on the arm rotating shaft 605, and the arm guide wheel 9 is installed on the arm joint support shaft 606 to play a guiding role. The arm joint support shaft 606 is machined with threads at both ends, is connected with the left arm plate 601 and the right arm plate 602, and is fixed with nuts to make the support of the two side plates stable. The arm driving unit 3 is pulled tightly by the small arm driving unit 4 through the small arm driving rope 1, and the motor brake of the arm driving unit 3 and the small arm driving unit 4 realizes the tensioning of the rope.

[0065] Referring to Figure 9 and Figure 10As shown, the forearm unit 10 includes a left forearm plate 1001, a right forearm plate 1002, a left forearm plate sleeve 1003, a right forearm plate sleeve 1004, a forearm rotating shaft 1005, a forearm joint support shaft 1006, an M5 internal hexagonal cylindrical head screw 1007, an M5 nut 1008, an M5 thin nut 1009, a forearm joint driving wheel 11, a forearm joint guide wheel 12, and a forearm guide wheel 13. The lower end holes of the left and right forearm plate sleeves 1003 and 1004 are both machined with key grooves and pin holes, which are connected with the shaft hole of the forearm rotating shaft 1005 through keys and pins to increase the driving performance. The left and right forearm plate sleeves 1003 and 1004 are connected and fixed with the left and right forearm plates 1001 and 1002 through the M5 internal hexagonal cylindrical head screw 1007, the M5 nut 1008, and the M5 thin nut 1009, and are connected with the forearm rotating shaft 1005 through keys. The forearm rotating shaft 1005 is machined with a key hole, and the forearm joint driving wheel 11 is connected with the forearm rotating shaft 1005 through a key to drive the forearm. The forearm rotating shaft 1005 connects the forearm unit 10 with the upper arm unit 5 through a key to play a connecting role. After the installation and compression of each component, the left and right forearm plate sleeves 603 and 604 below the upper arm unit 5 compress the forearm rotating shaft 1005 to play an axial fixing role. The forearm joint guide wheel 12 is installed on the forearm rotating shaft 1005, and the forearm guide wheel 13 is installed on the forearm joint support shaft 1006 to play a guiding role. The forearm joint support shaft 1006 is machined with threads at both ends, is connected with the left and right forearm plates 1001 and 1002, and is fixed with nuts to make the two side plates stable. The end driving unit 5 tightens the forearm unit 10 through the end driving rope 20, and the motor brake of the end driving unit 5 realizes the rope tensioning.

[0066] Referring to Figure 11As shown, the end unit 14 includes an end bracket top plate 1401, an end bracket left side plate 1402, an end right side plate 1403, an end rotating shaft 1404, an M3 round head screw 1405, an end driving wheel 15, and a tensioning device 21. The end bracket top plate 1401, the end bracket left side plate 1402, and the end right side plate 1403 are connected as a whole through screws. The lower end holes of the end bracket left side plate 1402 and the end right side plate 1403 are both processed with key grooves and pin holes, which are matched with the shaft hole of the end rotating shaft 1404, and are connected through keys and pins, thereby increasing the driving performance. The end rotating shaft 1404 is processed with a key hole, and the end driving wheel 15 is connected with the end rotating shaft 1404 through a key, thereby playing a role of driving the end. The end rotating shaft 1404 connects the end unit 14 with the small arm unit 10 through a key, thereby playing a role of connection. After the installation and fixation of each component, the end rotating shaft 1404 is pressed by the left small arm plate sleeve 1003 and the right small arm plate sleeve 1004 below the small arm unit 10, thereby playing a role of axial fixation. The tensioning device 21 tightens the motor brake of the end driving unit 5 to realize the tightening of the rope of the end unit 14.

[0067] Referring to Figure 12 , Figure 13 , Figure 14 , Figure 15 As shown, Figure 13 only the large arm driving rope is presented; Figure 14 only the small arm driving rope is presented; Figure 15Only the end-drive rope and tensioning device are shown. The tensioning principle and process of the rope includes: the forearm drive unit 4, the end-drive unit 5, the forearm drive rope 19, and the end-drive rope 20 tensioning the boom unit 6 and forearm unit 10, and the motor brakes of the boom drive unit 3, forearm drive unit 4, and end-drive unit 5 to achieve rope tensioning. The tensioning device 21 tensions the end-drive unit 14 and the motor brakes of the end-drive unit 5 to achieve rope tensioning of the end-drive unit 14. At this point, all parts are tensioned. In other words, when the forearm drive rope 19 is driven by the forearm drive unit 4, the rope on the forearm drive wheel 11 decreases, while the rope on the forearm drive rope 19 increases as it passes through other guide wheels, including the rope on the boom guide wheel 8. This process can be seen as the forearm drive rope 19 being driven by the forearm drive unit 4, which pulls up the entire boom unit 6, thus tensioning the rope. When the robotic arm is not in operation, the total length of the ropes remains constant due to the use of a drive motor that can brake in case of power failure, ensuring all drive ropes remain taut. Forearm tensioning is similar to upper arm tensioning, relying on the drive ropes of the next-level unit to achieve tension for that unit. For the end effector drive ropes, since there is no next-level unit at the end joint, tensioning device 21 is used to tension the ropes of end effector unit 14. The expansion and contraction of tension spring 2102 changes the amount of rope added or removed by tension wheel 2101, thereby pulling end effector unit 14. This tensioning design achieves the design goal of tensioning all drive ropes of the entire robotic arm with a single spring.

[0068] See Figure 12 , Figure 15 As shown, the tensioning device 21 includes a tension rope 2101 and a tension spring 2102. The tension rope 2101 and tension spring 2102 connect the tension wheel 2103 to the forearm support shaft 1006, thereby tensioning the end unit 14. A suitable preload is set by adjusting the tension of the tension spring 2102, and the free rotation of the end unit 14 is achieved by utilizing its length variation. The fixing point and length of the tension spring 2102 can be adjusted according to actual conditions, thus achieving the tensioning of the end unit.

[0069] See Figure 14 As shown, a drive rope 19 first winds around the motor drive wheel 4. Viewed from above, the rope passes from the right side of the right upper arm joint guide wheel 801, then from the left side through the first guide wheel 901-1 on the connecting rod, and then from the right side through the second guide wheel 901-2 on the connecting rod. Starting from the left side of the drive wheel 7 of joint 2, the rope winds counterclockwise around the drive wheel 7. When the motor drive force 4 rotates counterclockwise, it can drive the drive wheel 7 of joint 2 to rotate clockwise; when the motor drive force 4 rotates clockwise, the drive wheel 7 of joint 2 can rotate counterclockwise under the action of gravity and tension.

[0070] Referring to Figure 12 As shown, each driving rope is distributed on both sides of the driving wheel and the guide wheel; when the number of degrees of freedom of the mechanical arm needs to be increased, the arrangement mode of the driving rope 19 and the driving rope 20 can be imitated to increase the number of degrees of freedom of the mechanical arm. The rope arrangement mode can realize self-tensioning of the driving rope 18 and the driving rope 19. Although the driving rope 18 and the driving rope 19 are not added with a spring or other tensioning device in the patent, the two driving ropes will not be relaxed due to the action of other forces.

[0071] Referring to Figure 16 As shown, the guide wheel shaft 22 includes a sleeve 2201, a sleeve 2202, a sleeve 2203, a sleeve 2204, a sleeve 2205, a sleeve 2206, a sleeve 2207, a sleeve 2208, a sleeve 2209, a sleeve 2210, a sleeve 2211, and a sleeve 2212. The patent uses a sleeve to replace part of the axial fixing device or part, such as an elastic check ring, to simplify the structure of the mechanical arm. The sleeves on both sides are tightly attached to the parts and the arm plate. Since the width of the two side walls is constant and has been fixed by a bolt, the above-mentioned sleeve can fix the axial position of the pulley and other components.

[0072] Referring to Figure 17 , Figure 18 As shown, when the rope-driven mechanical arm is applied to an underwater environment, a waterproof motor should be used, and the motor is placed inside the underwater carrier. The arm body part of the mechanical arm is light in mass and has a hollow structure, and has excellent underwater operation ability when working outside the carrier.

[0073] Example two: application of the rope-driven mechanical arm on land

[0074] The application will be further described below with reference to the drawings.

[0075] Referring to Figure 19 , Figure 20 As shown, the application of the rope-driven mechanical arm on land only needs to change the direction of the mechanical claw and the winding direction of the driving wheel, and the other parts are the same as in example one.

[0076] Referring to Figure 21 , Figure 22 , Figure 23As shown, the tensioning principle of the rope-driven manipulator when working on land is as follows: compared with the tensioning principle of the rope-driven manipulator on the underwater carrier, the winding direction of the driving wheel is changed due to the change of the direction of gravity, thereby changing the traction direction of the motor (for example, from counterclockwise traction direction to clockwise traction direction), and other parts do not need to be modified. The forearm driving unit 4, the end driving unit 5, the large arm unit 6 and the forearm unit 10 are pulled tight by the forearm driving rope 19 and the end driving rope 20, and the motor brake of the large arm driving unit 3, the forearm driving unit 4 and the end driving unit 5 is additionally used to realize the tensioning of the rope. The motor brake of the end driving unit 5 and the tensioning device 21 pull the end unit 14 to realize the tensioning of the rope of the end unit 14, and thus all parts are fully tensioned.

[0077] When the manipulator is working, that is, when the forearm driving rope 19 is driven by the forearm driving unit 4, the rope reduction on the forearm driving wheel 11 is equal to the rope increment on the other guide wheels, including the rope on the large arm driven wheel 7. This process can be regarded as the whole large arm unit 5 being pulled up because the forearm driving rope 19 is driven by the forearm driving unit 4, thereby playing a role in tensioning the rope. When the manipulator is not working, because the driving motor can be braked when power is off, the total length of the rope is fixed and all driving ropes can be kept in tension. The forearm tensioning is similar to the large arm tensioning, that is, both rely on the driving of the next level unit to realize the tensioning of the current level unit. Since the end joint has no next level unit, the tensioning device 21 is used to pull the rope of the end unit 14, and the length change of the rope wound on the tensioning wheel 2101 is caused by the extension and retraction of the tensioning spring 2102, thereby pulling the end unit 14. Thus, the design goal of using one spring to tension all the ropes on the whole manipulator is achieved.

Claims

1. A multi-degree-of-freedom self-tensioning rope-driven robotic arm, comprising a base (1), a waist unit (2) extending downward from the base (1), a large arm unit (6) hinged to the waist unit (2), a small arm unit (10) hinged to the large arm unit (6), and an end effector unit (14) hinged to the small arm unit (10); further comprising a large arm drive unit (3), a small arm drive unit (4), and an end effector unit (5); characterized in that, The upper arm unit (6) is hinged to the waist unit (2) via an upper arm pivot (605). The upper arm pivot (605) is provided with a coaxial upper arm joint drive wheel (7), a right upper arm joint guide wheel (801), and a left upper arm joint guide wheel (802). The upper arm unit is also provided with an upper arm joint support shaft (606) located downstream of the upper arm pivot (605) and parallel to the upper arm pivot (605). The upper arm joint support shaft (606) is provided with a left upper arm guide wheel (902-1) and a right upper arm guide wheel (901-1). The lower arm unit (10) is hinged to the upper arm unit (6) via a lower arm pivot (1005). The lower arm pivot (1005) is provided with a coaxial lower arm joint drive wheel (11) and a lower arm joint guide wheel (802-1). Wheel (12); the forearm unit (10) is also provided with a forearm guide wheel shaft (23) located downstream of the forearm pivot (1005) and parallel to the forearm pivot (1005), and a forearm guide wheel (13) is provided on the forearm guide wheel shaft (23); the end drive unit (5) is hinged to the forearm unit (10) through the end pivot (1404), and a coaxial end drive wheel (15) and tension wheel (2103) are provided on the end pivot (1404); a tension rope (2101) is fixed on the tension wheel (2103), and one end of the tension rope (2101) extending from the tension wheel (2103) provides tension force to the tension wheel (2103) and the end drive wheel (15) through a tension spring (2102); The upper arm drive unit (3), the lower arm drive unit (4), and the end drive unit (5) are all rope drive units; the upper arm drive unit (3) has an upper arm drive rope (18), the end of which is wound and fixed to the upper arm joint drive wheel (7); the lower arm drive unit (4) has a lower arm drive rope (19), which passes through the right upper arm joint guide wheel (801) and the right upper arm guide wheel (901-1) in sequence, and then the end of which is wound and fixed to the lower arm joint drive wheel (11); the end drive unit (5) has an end drive rope (20), which passes through the left upper arm joint guide wheel (802), the left upper arm guide wheel (902-1), and the lower arm joint in sequence. The rear ends of the guide wheel (12) and the forearm guide wheel (13) are wound and fixed with the end drive wheel (15); the forearm drive rope (19) and the end drive rope (20) are arranged in one or more figure-eight shapes between the upper arm pivot (605) and the forearm pivot (1005), and the tangent point of the forearm drive rope (19) on the right upper arm joint guide wheel (801) and the tangent point of the upper arm drive rope (18) on the upper arm joint drive wheel (7) are respectively located on both sides of the upper arm pivot (605); the tangent point of the end drive rope (20) on the forearm joint guide wheel (12) and the tangent point of the forearm drive rope (19) on the forearm joint drive wheel (11) are respectively located on both sides of the forearm pivot (1005).

2. The multi-degree-of-freedom self-tensioning rope-driven robotic arm as described in claim 1, characterized in that, The end drive rope (20) is used to rotate the end unit (14) clockwise, the forearm drive rope (19) is used to rotate the forearm unit (10) clockwise, and the upper arm drive rope (18) is used to rotate the upper arm unit (6) clockwise; the tension spring (2102) pulls the tension rope (2101) to make the end unit (14) have a counterclockwise rotation tendency to tighten the end drive rope (20); the end drive rope (20) pulls the forearm unit (10) to make the forearm unit (10) have a counterclockwise rotation tendency to tighten the forearm drive rope (19); the forearm drive rope (19) pulls the upper arm unit (6) to make the upper arm unit (6) have a counterclockwise rotation tendency to tighten the upper arm drive rope (18); Alternatively, the end drive rope (20) is used to rotate the end unit (14) counterclockwise, the forearm drive rope (19) is used to rotate the forearm unit (10) counterclockwise, and the upper arm drive rope (18) is used to rotate the upper arm unit (6) counterclockwise; the tension spring (2102) pulls the tension rope (2101) to make the end unit (14) have a clockwise rotation tendency to tighten the end drive rope (20); the end drive rope (20) pulls the forearm unit (10) to make the forearm unit (10) have a clockwise rotation tendency to tighten the forearm drive rope (19); the forearm drive rope (19) pulls the upper arm unit (6) to make the upper arm unit (6) have a clockwise rotation tendency to tighten the upper arm drive rope (18).

3. The multi-degree-of-freedom self-tensioning rope-driven robotic arm as described in claim 1, characterized in that, When the rope-driven robotic arm is used in an underwater environment, the large arm drive unit (3), the small arm drive unit (4) and the end drive unit (5) all use waterproof motors and place the waterproof motors inside the underwater vehicle. The boom drive unit (3), the forearm drive unit (4) and the end drive unit (5) are all mounted on the base (1).

4. The multi-degree-of-freedom self-tensioning rope-driven robotic arm as described in claim 1, characterized in that, The forearm guide wheel shaft (23) is provided with multiple shafts, and the forearm drive rope (19) is arranged in multiple S-shaped connections between the forearm pivot (1005) and the end pivot (1404).

5. The multi-degree-of-freedom self-tensioning rope-driven robotic arm as described in claim 4, characterized in that, One end of the tension spring (2102) is connected and fixed to the tension rope (2101), and the other end of the tension spring (2102) is fixed to the guide wheel shaft (23) of a forearm.

6. The multi-degree-of-freedom self-tensioning rope-driven robotic arm as described in claim 2, characterized in that, The motor brakes of the boom drive unit, forearm drive unit, and end effector drive unit achieve rope tensioning.

7. The multi-degree-of-freedom self-tensioning rope-driven robotic arm as described in claim 1, characterized in that, The motor drive wheel of the boom drive unit (3) and the central symmetry line of the boom joint drive wheel (7) are kept in the same plane; the motor drive wheel of the forearm drive unit (4) and the central symmetry line of the boom joint guide wheel (801), boom guide wheel (901-1, 901-2) and forearm drive wheel (11) are kept in the same plane; the motor drive wheel of the end drive unit (5) and the central symmetry line of the boom guide wheel (902-1, 902-2), forearm joint guide wheel (12), forearm guide wheel (13) and end drive wheel (15) are kept in the same plane.

8. The multi-degree-of-freedom self-tensioning rope-driven robotic arm as described in claim 1, characterized in that, By adjusting the tension of the tension spring (2102) to set a suitable tension preload, the free rotation of the end unit (14) can be achieved by utilizing the change in the length of the tension spring (2102).

9. The multi-degree-of-freedom self-tensioning rope-driven robotic arm as described in claim 1, characterized in that, It can be used both underwater and on land.

10. The multi-degree-of-freedom self-tensioning rope-driven robotic arm as described in claim 9, characterized in that, The robotic arm has a hollow structure, and the guide wheel axle uses a tubular structure.

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