CN117921728A

CN117921728A - Closed loop rope-driven triaxial parallel large-posture space humanoid wrist capable of passing through fixed-length cable

Info

Publication number: CN117921728A
Application number: CN202310856470.7A
Authority: CN
Inventors: 曹文熬; 程鹏; 丁华锋; 陈建宇; 李世魏; 黄新博; 葛明峰
Original assignee: China University of Geosciences
Current assignee: China University of Geosciences
Priority date: 2023-07-12
Filing date: 2023-07-12
Publication date: 2024-04-26

Abstract

The invention provides a three-axis parallel large-posture space humanoid wrist driven by a closed loop rope of a fixed-length cable, belongs to the field of robots, and particularly relates to a humanoid wrist robot; the device comprises three motors, a static platform, a movable platform, three driving rods and three driven rods which are connected in parallel between the static platform and the movable platform, three groups of guide components and three pairs of driving ropes; one ends of the three pairs of driving ropes are respectively connected to the output shafts of the three motors, and the other ends of the three pairs of driving ropes are respectively fixedly connected with the three driving rods through the three groups of guide assemblies to form a closed loop rope driving. The invention can simultaneously meet the advantages of simple structure, triaxial rotation, large gesture space, closed loop rope driving, simple mathematical model and the like.

Description

Closed loop rope-driven triaxial parallel large-posture space humanoid wrist capable of passing through fixed-length cable

Technical Field

The invention provides a three-axis parallel large-posture space humanoid wrist driven by a closed loop rope of a fixed-length cable, belongs to the technical field of robots, and particularly relates to a humanoid wrist robot.

Background

With the continuous development of robotics, a humanoid manipulator has become one of the hot-spot research objects in the robotics field. The humanoid manipulator is a robot which simulates the structure and the movement mode of human hands and realizes the grabbing and the operation of the manipulator on objects. It is applied to the fields such as industrial production, medical treatment, disability rehabilitation and the like.

The humanoid robot wrist is an important component of the humanoid robot, and has important influence on the performance and application of the humanoid robot. The good design of the humanoid mechanical wrist can improve the operation capability and efficiency of the mechanical arm, and has important practical significance and application value. In recent decades, many research institutions at home and abroad have made remarkable researches on bionic wrists, and some bionic wrists have been successfully developed. The Chinese patent (CN 107351064A) proposes a two-degree-of-freedom parallel humanoid wrist, the wrist adopts two semicircular arc follow-up pointing rod pieces, a motor drives the semicircular arc pointing rod pieces through a gear, the two-degree-of-freedom motion of a mechanism is realized, the freedom and flexibility are realized, the precision is high, but more serious friction and abrasion exist between the rod pieces, the service life is short, the load capacity is limited, and the cable of an end effector is inconvenient to arrange. The Chinese patent (CN 209793782U) proposes a humanoid robot wrist with orthogonal motion axes of two degrees of freedom of the robot wrist, and the wrist is driven by adopting a bevel gear and a synchronous pulley, so that the precision is high, the precise control is convenient, but the structure is complex, the external dimension is large, the mass is heavy, the motion freedom degree is less, the flexibility degree is lower, and the operable space is small. The Chinese patent (CN 214724204U) proposes a rope-driven wrist module based on a three-degree-of-freedom serial-parallel mechanism, the wrist has a large gesture space and is flexible, but the wrist module adopts a parallel-serial structure, the connecting rod is too many, the structure is complex, the rotation of a movable platform around a fixed point cannot be realized, an end effector cable cannot conveniently pass through the center of the wrist, and the kinematic inverse solution of the end effector cable has no analytic solution, so that the mathematical model is complex and inconvenient to control. The Chinese patent (CN 113305807A) proposes a bionic wrist joint based on an asymmetric 3-RRR parallel mechanism, the wrist adopts a parallel mechanism, the structure is simple, the mathematical model is simple, but the wrist gesture space is smaller, the wrist gesture space adopts gear transmission, the mass is larger, and the rotating point of a movable platform of the wrist is not positioned in the geometric center of the wrist, and cannot pass through a fixed-length cable of an end effector.

The existing humanoid parallel or serial-parallel wrist with different types has the following problems: (1) The existing ropes drive cables of various types to pass through the tail end actuator without space in the wrist, or the lengths of the cables which can not pass through the wrist can not be changed even if the space exists, so that the cables are exposed outside the wrist or are wound with a rod piece of the wrist, and a great potential safety hazard exists; (2) The existing three-axis parallel wrist has small gesture space and can not completely realize the movement of the wrist; (3) The existing triaxial parallel wrist can not realize closed loop rope driving, four or more driving ropes are needed to be utilized, and a driving system is complex; (4) The advantages of simple structure, triaxial rotation, large attitude space, closed loop rope driving, simple mathematical model and the like cannot be simultaneously met, and obvious short plates can be caused in application.

The three-axis parallel-connected large-posture space humanoid wrist can be driven by the closed loop rope of the fixed-length cable, has three degrees of freedom, is driven by the wrist joint through the rope, realizes rope-driven closed loop, and has a simple driving system; the invention adopts a special parallel mechanism design, has few rod pieces and simple structure, and enhances the rigidity of the wrist, so that the wrist has better operation stability and balance; the special rod piece design and the special driving system design enable the gesture space of the wrist to be large, and the movement of the wrist of the person can be completely realized; the movable platform of the humanoid wrist robot only rotates around the geometric center of the movable platform, and the distance from the geometric center to the static platform is kept unchanged, so that the length of a cable of the end effector passing through the wrist is kept unchanged, and the safety and the attractiveness of the cable arrangement of the end effector are greatly improved; the invention can simultaneously meet the advantages of simple structure, triaxial rotation, large gesture space, closed loop rope driving, simple mathematical model and the like.

Disclosure of Invention

Aiming at the defects of the prior art, the technical scheme of the invention provides the three-axis parallel large-posture space humanoid wrist which can be driven by a closed loop rope of a fixed-length cable.

The technical scheme of the invention provides a three-axis parallel large-posture space humanoid wrist driven by a closed loop rope of a fixed-length cable, which comprises three motors, a static platform, a movable platform, three driving rods, three driven rods, three groups of guide components and three pairs of driving ropes, wherein the three driving rods and the three driven rods are connected between the static platform and the movable platform in parallel;

The three driving rods are divided into a driving rod I, a driving rod II and a driving rod III, the three driven rods are divided into a driven rod I, a driven rod II and a driven rod III, the three motors are divided into a motor I, a motor II and a motor III, each pair of driving ropes is a pair of driving ropes for driving the same rotary joint in a closed loop manner, each pair of driving ropes is divided into a first driving rope, a second driving rope and a third driving rope, the guide assembly comprises a guide wheel and a guide hole, a winding groove is formed in the outer cylindrical surface of the static platform, a large-diameter through hole is formed in the center of the static platform, and the guide assembly is arranged on the static platform;

The first motor, the second motor and the third motor are fixedly connected with the static platform, one end of the first driving rope is connected with an output shaft of the first motor, the other end of the first driving rope is fixedly connected with the first driving rod after being lapped and wound on the opposite side in a winding groove of the cylindrical surface of the static platform through the first guide wheel and the first guide hole, closed-loop driving is formed, the first driving rod is connected with the static platform through the first revolute pair, the first driven rod is connected with the first driving rod through the fourth revolute pair, and the first driven rod is connected with the movable platform through the seventh revolute pair; the arrangement mode of the second driving rope on the motor II, the static platform and the driving rod II is the same as that of the first driving rope, the driving rod II is connected with the static platform through a rotating pair II, the driven rod II is connected with the driving rod II through a rotating pair V, and the driven rod II is connected with the moving platform through a rotating pair eight; the arrangement mode of the third driving rope on the motor III, the static platform and the driving rod III is the same as that of the first driving rope, the driving rod III is connected with the static platform through a revolute pair III, the driven rod III is connected with the driving rod III through a revolute pair six, and the driven rod III is connected with the moving platform through a revolute pair nine; the axes of the first revolute pair, the second revolute pair and the third revolute pair are coincident and perpendicular to the plane of the static platform, and the axes of the first revolute pair, the second revolute pair, the third revolute pair, the fourth revolute pair, the fifth revolute pair, the sixth revolute pair, the seventh revolute pair, the eighth revolute pair and the ninth revolute pair are converged at one point, and the point is the geometric center of the movable platform; the rotation ranges of the first revolute pair, the second revolute pair and the third revolute pair are +/-180 degrees, and the movable platform can realize three-degree-of-freedom gesture conversion in a larger range around the geometric center fixed point.

The technical scheme provided by the invention has the beneficial effects that: the parallel mechanism is adopted, so that the rigidity is high, the number of rod pieces is small, and the structure is simple; the joints are driven by ropes, closed-loop rope driving is realized, and a driving system is simple; the joint rotation angle is large, the gesture space is large, the operations such as grabbing and placing of the articles can be more flexibly completed, and further more complex tasks can be completed; the kinematic inverse solution has an analytical solution, and the mathematical model is simple and convenient to control; the center can pass through the fixed-length cable, so that the aesthetic property and the safety of the cable are greatly improved; the three-axis three-dimensional rotating device can simultaneously meet the advantages of simple structure, three-axis rotation, large gesture space, closed-loop rope driving, simple mathematical model and the like.

Drawings

FIG. 1 is a schematic diagram of the overall structure of a three-axis parallel large-attitude space humanoid wrist driven by a closed loop rope of a fixed-length cable;

FIG. 2 is a schematic diagram showing the connection of a motor and a driving rod of a three-axis parallel-connected large-posture space humanoid wrist driven by a closed loop rope of a fixed-length cable;

FIG. 3 is a schematic view of another view of a motor connected to a drive rod for driving a triaxial parallel-connected large-posture space humanoid wrist through a closed loop rope of a fixed length cable according to the present invention;

In the figure, a 1-static platform, a 2-moving platform, a-motor I, b-motor II, c-motor III, L1-driving rod I, L2-driving rod II, L3-driving rod III, L4-driven rod I, L5-driven rod II, L6-driven rod III, W1-guide wheel I, W2-guide wheel II, W3-guide wheel III, D1-reel I, D2-reel II, D3-reel III, S1-first driving rope, S2-second driving rope, S3-third driving rope, K1-guide hole I, K2-guide hole II, K3-guide hole III, R1-revolute pair I, R2-revolute pair II, R3-revolute pair III, R4-revolute pair IV, R5-revolute pair 5, R6-revolute pair VI, R7-revolute pair seven, R8-revolute pair eight and R9-revolute pair nine.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be further described with reference to the accompanying drawings.

In this document, terms of front, rear, upper, lower, inner, outer, etc. are defined with respect to the positions of the components in the drawings and with respect to each other, for clarity and convenience in expressing the technical solution. It should be understood that the use of such orientation terms should not limit the scope of the claimed application.

In this document, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the terms herein above will be understood by those of ordinary skill in the art as the case may be.

Referring to fig. 1,2 and 3, an embodiment of the present invention provides a three-axis parallel-connected large-posture space humanoid wrist driven by a closed loop rope of a fixed-length cable, which comprises three motors, a static platform 1, a dynamic platform 2, three driving rods and three driven rods connected in parallel between the static platform 1 and the dynamic platform 2, three groups of guide assemblies and three pairs of driving ropes;

The three driving rods are divided into a driving rod I L1, a driving rod II L2 and a driving rod III L3, the three driven rods are divided into a driven rod I L4, a driven rod II L5 and a driven rod III L6, the three motors are divided into a motor I a, a motor II b and a motor III c, each pair of driving ropes is a pair of driving ropes for driving the same rotary joint in a closed loop manner, each pair of driving ropes is divided into a first S1 driving rope, a second S2 driving rope and a third S3 driving rope, the guiding assembly comprises a guiding wheel and a guiding hole, a winding groove is formed in the outer cylindrical surface of the static platform 1, a large-diameter through hole is formed in the center of the static platform 1, and the guiding assembly is arranged on the static platform 1;

The motor A, the motor B and the motor C are fixedly connected with the static platform 1, one end of a first driving rope S1 is wound on a wire winding wheel D1 in the opposite direction, the wire winding wheel D1 is fixedly connected with an output shaft of the motor A, the other end of the first driving rope is fixedly connected with a driving rod L1 after being wound on the opposite side in a winding groove of the cylindrical surface of the static platform 1 through a guide wheel W1 and a guide hole K1 to form closed-loop driving, the driving rod L1 is connected with the static platform 1 through a revolute pair R1, a driven rod L4 is connected with the driving rod L1 through a revolute pair four R4, and the driven rod L4 is connected with a movable platform 2 through a revolute pair seven R7; the arrangement mode of the second driving rope on the motor B, the static platform 1 and the driving rod L2 is the same as that of the first driving rope S1, the driving rod L2 is connected with the static platform 1 through a rotating pair R2, a driven rod L5 is connected with the driving rod L2 through a rotating pair five R5, and the driven rod L5 is connected with the moving platform 2 through a rotating pair eight R8; the arrangement mode of the third driving rope on the motor tric, the static platform 1 and the driving rod tric L3 is the same as that of the first driving rope S1, the driving rod tric L3 is connected with the static platform 1 through a revolute pair tric R3, a driven rod tric L6 is connected with the driving rod tric L3 through a revolute pair tric R6, and the driven rod tric L6 is connected with the movable platform 2 through a revolute pair tric R9; the axes of the first revolute pair R1, the second revolute pair R2 and the third revolute pair R3 are coincident and perpendicular to the plane of the static platform 1, and the axes of the first revolute pair R1, the second revolute pair R2, the third revolute pair R3, the fourth revolute pair R4, the fifth revolute pair R5, the sixth revolute pair R6, the seventh revolute pair R7, the eighth revolute pair R8 and the ninth revolute pair R9 are converged at one point and the point is the geometric center of the dynamic platform 2; the rotation ranges of the first revolute pair R1, the second revolute pair R2 and the third revolute pair R3 are all +/-180 degrees, and the movable platform 2 can realize three-degree-of-freedom gesture conversion in a larger range around the geometric center fixed point.

The embodiments described above and features of the embodiments herein may be combined with each other without conflict.

The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims

1. A three-axis parallel large-posture space humanoid wrist driven by a closed loop rope of a fixed-length cable belongs to the field of robots, and particularly relates to a humanoid wrist robot; the method is characterized in that: the device comprises three motors, a static platform, a movable platform, three driving rods and three driven rods which are connected in parallel between the static platform and the movable platform, three groups of guide components and three pairs of driving ropes;