An underactuated manipulator based on gear and tendon hybrid transmission

Abstract

This utility model discloses an underactuated manipulator based on a hybrid transmission of gears and tendon ligament mechanisms, belonging to the field of manipulator technology. It includes an intermediate connecting mechanism; one end of the intermediate connecting mechanism is equipped with a floating platform underactuated mechanism, and the other end is equipped with three identical finger mechanisms. The floating platform underactuated mechanism includes a tendon ligament lifting device, a floating platform, a tendon ligament wheel, and a drive motor. The tendon ligament passes through the lifting device, connects to the floating platform, and reaches the finger mechanisms, achieving synchronous control of the finger mechanisms. The finger mechanisms sequentially include a wrist joint, an MP joint, and a proximal phalanx, each driven by a separate motor to achieve rotary motion. The proximal phalanx is connected in series with a DIP joint, an intermediate phalanx, a PIP joint, and a distal phalanx, transmitted via tendon ligaments and equipped with a flexible band on its inner side, achieving adaptive grasping and gripping. Simultaneously, torsion springs and limiting devices are installed at the joints to achieve reset and self-locking functions. This underactuated manipulator exhibits strong adaptability, high flexibility, and good stability.

Description

Technical Field

[0001] This invention relates to the field of robotic arm technology, specifically to an underactuated robotic arm based on a hybrid transmission of gears and tendon cord mechanisms. Background Technology

[0002] With the rapid development of modern society and technology, robotics has become a cutting-edge technology that is widely valued by countries around the world, and has been widely developed and applied in many fields such as industrial production, marine development, space development, national defense, and daily life services. As the working tool of robots, the end effector of robots can provide robots with more precise and stable grasping capabilities, expanding and extending the application range of robots. Therefore, its importance is becoming more prominent with the widespread application of robots.

[0003] Robot end effectors can be broadly classified into two types: dedicated end effectors and general-purpose end effectors. Dedicated end effectors are characterized by simple manufacturing, ease of control, and large grasping force, but they are highly specific to the objects they grasp. Their drive method is mostly pneumatic, and they are suitable for applications where the gripper opens and closes frequently. General-purpose end effectors are mostly multi-fingered dexterous hands. In this type of hand, each joint is usually independently driven and controlled, and the joints mostly adopt a series structure. In addition, each degree of freedom of the hand is mostly equipped with a driver and a measuring sensor. This approach results in a large number of drivers being accumulated in multi-fingered dexterous hands, which makes the control strategy more complex and the reliability relatively poor. In the further development of multi-fingered dexterous hands, underactuated grippers have emerged.

[0004] In conclusion, with the development of technology and the progress of society, universal, intelligent, and highly adaptable robotic arms capable of handling complex and harsh environments are indispensable. However, existing dedicated robotic arms are insufficient to meet these requirements, while general-purpose fully actuated multi-finger dexterous robotic arms suffer from drawbacks such as complex control and relatively poor reliability. Therefore, we propose an underactuated robotic arm based on a hybrid transmission system of gears and tendon ligaments. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the existing defects and provide an underactuated manipulator based on a hybrid transmission of gear and tendon mechanism. It has strong adaptability, good stability and high flexibility. It breaks through the weaknesses of special-purpose and general-purpose manipulators, such as complex structure, poor reliability, low universality and poor adaptability to tasks in complex and harsh environments. It can effectively solve the problems in the background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an underactuated manipulator based on a hybrid transmission of gears and tendon ligament mechanisms, comprising:

[0007] The intermediate connecting mechanism includes an L-shaped fixing frame, a base frame 1, a base frame 2, and a second copper column. The base frame 1 and the base frame 2 are fixedly connected through the second copper column, and the L-shaped fixing frame is fixedly connected to the base frame 2.

[0008] The underdriven mechanism of the floating platform includes a tendon ligament lifting device fixing frame, a tendon ligament rising guide tube, a tendon ligament winding wheel, a tendon ligament drive motor, a floating platform, and a first copper column. The tendon ligament lifting device fixing frame is installed on the base frame 1, and a tendon ligament rising guide tube is threaded to its center. The floating platform is fitted inside the tendon ligament rising guide tube. An independent tendon ligament drive motor is installed on one side of the tendon ligament lifting device fixing frame. The lower end of the motor is connected to the base frame 1 through the first copper column, and the upper end is connected to the tendon ligament winding wheel. The tendon ligament starts from the tendon ligament winding wheel, passes over the tendon ligament lifting device fixing frame, passes through the tendon ligament rising guide tube, and then connects to the floating platform.

[0009] Finger mechanism: includes wrist joint, MP joint, proximal phalanx, proximal phalanx support, DIP joint, intermediate phalanx, PIP joint and distal phalanx. The wrist joint includes a wrist joint rotation drive motor and a wrist joint rotation shaft. One end of the wrist joint rotation shaft is connected to the wrist joint rotation drive motor via a coupling, and the other end is connected to the proximal phalanx support. One end of the MP joint is connected to the MP joint drive motor, and the other end is connected to the front end of the proximal phalanx. There is a round shaft near the lower middle of the proximal phalanx, which is fixedly connected to the L-shaped bracket. The distal end of the proximal phalanx is connected in series with the PIP joint, intermediate phalanx, DIP joint and distal phalanx.

[0010] The finger mechanism, as the main body of the underactuated manipulator based on a hybrid transmission of gears and tendon cords, is used for grasping and pinching objects. The wrist joint is equipped with a drive motor to achieve rotational freedom. To achieve self-locking function, precise pinching, and lag-free response, the proximal phalanx uses gear transmission as the transmission scheme and takes advantage of the characteristics of worm gear transmission, directly controlled by a motor. To simulate the free and smooth switching between pinching and grasping movements of a human hand, the middle and distal phalanxes are driven by the contraction of tendon cords combined with torsion springs. The torsion springs are installed at the DIP and PIP joints and are equipped with limiting devices. A pulley is located in the middle of the middle phalanx to connect to the tendon cord, and a straight groove is provided at the distal end. The distal phalanx is connected to the middle phalanx through the straight groove, thereby improving the flexibility and adaptability of the distal phalanx. The finger design adopts a rigid structure on the outside for grasping drive and stable support, while the inside uses tendon cords with a flexible band structure for grasping interaction, realizing pinching at the fingertip and flexible contact grasping with adaptive and uniformly distributed pressure on the envelope surface on the inside of the finger.

[0011] Furthermore, the MP joint includes an MP joint drive motor, a proximal phalanx support, and a bearing. The MP joint of the finger is fixed on the proximal phalanx support, which is connected to an L-shaped fixing frame. The L-shaped fixing frame is then fixedly connected to the base frame 2. This connection part replaces the wrist joint slewing bearing to bear the main load.

[0012] Furthermore, the DIP joint includes an arc-shaped adjustable limiting device, a torsion spring, and a bearing, wherein the torsion spring causes the finger mechanism to return to its initial position after the grasping task is completed, and the torsion spring is limited by the arc-shaped adjustable limiting device.

[0013] Furthermore, the intermediate phalanx includes a straight groove design, a limiting design, and a tendon cord pulley design. The distal phalanx is slidably connected to the intermediate phalanx through the straight groove to achieve flexible switching between the gripping and holding states of the robotic arm. The limiting design includes a protrusion on the back of the distal phalanx and the end of the intermediate phalanx. A pulley is installed on the intermediate phalanx to adjust the direction of the tendon cord.

[0014] The aforementioned floating platform underactuated mechanism simplifies the structure of the robotic arm, which contains three identical fingers.

[0015] The floating platform connects three finger mechanisms simultaneously via tendon chords, enabling synchronized control of the finger mechanisms and reducing the number of actuators. At the same time, the floating platform and tendon chord ascending guide tube protect the tendon chords, making the robot more adaptable to complex and extreme environments.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This underactuated adaptive manipulator has the following advantages:

[0017] 1. High adaptability and flexibility. The finger mechanism of this robotic hand, designed based on the underactuated principle, adopts a hybrid transmission method of gears and tendons (with tendons as the main component), which has the interactive ability of external rigidity and internal flexibility, realizing stable and rapid adaptive grasping of the target object to be gripped; at the same time, the two-degree-of-freedom dexterity design of the distal phalanx enables the robotic hand to switch between fingertip pinching and envelope gripping.

[0018] 2. High stability. The finger mechanism and floating platform mechanism of this robotic arm adopt an underactuated method, which reduces the number of driving components. Furthermore, the drive system and transmission system are installed separately for long-distance transmission. In environments with strong radiation, microgravity, and large temperature differences, this installation method is beneficial for shielding and protecting the drive system, enabling the robotic arm to work flexibly in complex and extreme environments.

[0019] 3. High reliability. The main actuators of this robot are all mechanical structures, and the design based on the underactuated principle greatly reduces the number of drive components, thereby reducing the probability of electronic component failure and increasing the reliability of the robot's operation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of an underactuated manipulator based on a hybrid transmission of gears and tendon ligaments according to the present invention.

[0021] Figure 2 This is a schematic diagram of an underactuated mechanism for a floating platform of an underactuated manipulator based on a hybrid transmission of gears and tendon rope mechanisms according to the present invention.

[0022] Figure 3 This is a schematic diagram of an intermediate connection mechanism for an underactuated manipulator based on a hybrid transmission of gears and tendon cord mechanisms according to the present invention.

[0023] Figure 4 This is a schematic diagram of an underactuated manipulator finger mechanism based on a hybrid transmission of gears and tendon ligaments according to the present invention.

[0024] Figure 5 This is a schematic diagram of an underactuated manipulator finger explosion mechanism based on a hybrid transmission of gears and tendon ligaments according to the present invention.

[0025] In the diagram: 1. Floating platform underdrive mechanism, 11. Tendon cord winding wheel, 12. Tendon cord drive motor, 13. First copper column, 14. Tendon cord lifting device fixing frame, 15. Tendon cord rising guide tube, 16. Floating platform, 2. Intermediate connecting mechanism, 21. Base frame 1, 22. Second copper column, 23. Base frame 2, 24. L-shaped fixing frame, 31. Wrist joint rotation drive motor, 32. Wrist joint rotation shaft, 33. MP joint drive motor, 34. MP joint, 341. Proximal phalanx support, 342. Bearing, 343. Rotation shaft, 35. Proximal phalanx, 36. Limiting device, 361. Arc-shaped adjustable limiting device, 362. Torsion spring, 37. PIP joint, 371. Rolling shaft, 38. Intermediate phalanx, 381. Pulley, 39. Tendon cord, 40. DIP joint, 41. Distal phalanx. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the present invention

[0027] All other embodiments obtained by those skilled in the art without inventive effort, as described in the embodiments herein, are within the scope of protection of this invention.

[0028] Example 1, please refer to Figures 1 to 4 This embodiment provides a technical solution: an underactuated manipulator based on a hybrid transmission of gears and tendon rope mechanisms, including a floating platform underactuated mechanism 1, an intermediate connecting mechanism 2, and a finger mechanism 3.

[0029] The underdrive mechanism 1 of the floating platform includes a tendon rope lifting device fixing frame 14, a tendon rope rising guide tube 15, a tendon rope winding wheel 11, a tendon rope drive motor 12, a floating platform 16, and a first copper column 13. The tendon rope lifting device fixing frame 14 is threadedly mounted on the base frame 1, and the tendon rope rising guide tube 15 is fixedly mounted in the middle by threads. The floating platform 16 is fitted inside the tendon rope rising guide tube and can slide up and down. The tendon rope drive motor 12 and the tendon rope winding wheel 11 are fixedly mounted on the base frame 1 and close to the tendon rope lifting device fixing frame 14 through the first copper column 13. The tendon rope winding wheel 11 winds the tendon rope and guides the tendon rope to the tendon rope rising guide tube 15. The tendon rope wind wheel 11 passes through the tendon rope rising guide tube 15 and through the middle hole of the floating platform 16, so as to realize the control of the up and down movement of the floating platform by the tendon rope winding wheel 11 through the winding and unwinding of the tendon rope.

[0030] The intermediate connecting mechanism 2 includes an L-shaped fixing frame 24, a base frame 1 21, a base frame 2 23, and a second copper column 22. The base frame 1 21 is used to connect the upper floating platform underdrive mechanism 1 and provide space for the installation of the wrist joint rotation drive motor 31. The base frame 2 23 is threadedly connected to the L-shaped fixing frame 24 to connect the lower finger mechanism. The base frame 1 21 and the base frame 2 23 are connected and fixed by the second copper column 22.

[0031] There are three finger mechanisms arranged in a 120° circle around the base frame 1, including a wrist joint, MP joint 34, proximal phalanx 35, proximal phalanx support 341, DIP joint 40, intermediate phalanx 38, PIP joint 37, and distal phalanx 41.

[0032] The wrist joint includes a wrist joint rotation drive motor 31 and a wrist joint rotation shaft 32. One end of the wrist joint rotation shaft 32 is connected to its independent drive motor 31 via a coupling, and the other end is connected to the proximal phalanx support 341. The motor drives the rotation shaft to provide the finger mechanism 3 with the freedom to rotate around the axis.

[0033] The MP joint 34 includes an MP joint drive motor 33, a proximal phalanx support 341, and a bearing 342. The MP joint 34 of the finger is fixed on the proximal phalanx support 341, which is connected to an L-shaped fixing frame 24. The L-shaped fixing frame 24 is then fixedly connected to the base frame 223. This connection part replaces the wrist joint slewing bearing to bear the main load. At the same time, the MP joint 34 is directly controlled by the motor. Thus, the proximal phalanx 35 uses gear transmission as the transmission scheme and utilizes the characteristics of a worm gear reducer to achieve self-locking function, precise pinching, and lag-free response.

[0034] Example 2, please refer to Figure 5 This embodiment provides a technical solution: an underactuated manipulator based on a hybrid transmission of gears and tendon rope mechanism. This embodiment is a further explanation of the structure of Embodiment 1.

[0035] The PIP joint 37 of the finger mechanism includes a torsion spring 362, an arc-shaped adjustable limiting device 361, and a rotation shaft 343. To ensure that it is in an open state before grasping and returns to its initial position after the grasping task is completed, a torsion spring 362 is installed at the joint, and a limiting device, the arc-shaped adjustable limiting device 361, is also designed. One end of the intermediate phalanx 38 is connected in series with the PIP joint 37, and the other end is designed with a straight groove connected in series with the distal phalanx. The intermediate phalanx 38 is also designed with a pulley 381 to guide the tendon ligament 39 and ensure its smooth movement. The distal phalanx 41 is installed in the straight groove, giving it two degrees of freedom: rotation around the DIP joint 40 and sliding along the straight groove, allowing it to be converted from a pinching state to a gripping state. To ensure... After the grasping task is completed, the distal phalanx returns to its initial position. A torsion spring is also designed at the DIP joint 40. The limiting between the distal and middle phalanges is formed by the connection between the back of the distal phalanx and the protrusion at the end of the middle phalanx. The middle phalanx 38 and the distal phalanx 41 are driven by tendon cords 39. The finger design adopts a rigid structure on the outside as the grasping drive and stable support, and the inside has a flexible contact grip with adaptive and uniformly distributed pressure on the envelope surface. At the same time, machine vision is used to judge the shape characteristics of the target object, and then adjust the grasping orientation and posture of the robot arm to automatically adapt to and conform to the surface shape of the grasped object, so as to achieve non-destructive and reliable grasping. The tendon cords 39 of the three finger mechanisms 3 arranged in a 120° circle pass through the base frame 1 21 and converge to the floating platform 16, so that the floating platform 16 can control the opening and closing of the three finger mechanisms 3 at the same time, reducing the number of actuators.

[0036] 1. Compared with existing technologies, this underactuated manipulator based on a hybrid transmission of gear and tendon mechanism overcomes the problems of underactuated flexible manipulators at home and abroad, which, although they can passively adapt to the surface shape of the object being grasped, are difficult to perfectly fit and have uneven grasping force. It innovatively designs an underactuated adaptive manipulator that can achieve flexible contact and automatically adapt to fit the outer contour shape of the object being grasped in order to grasp target objects of different shapes.

[0037] 2. Compared with the prior art, the finger mechanism of the underactuated manipulator based on the hybrid transmission of gear and tendon mechanism of the present invention adopts a biomimetic design and is composed of a rotating wrist joint, a condylar MP joint, an intermediate PIP joint and a distal DIP joint. It uses a hybrid transmission of gear and tendon mechanism and has the interactive ability of external rigidity and internal flexibility to achieve adaptive enveloping grasping and pinching.

[0038] 3. Compared with the prior art, the underactuated manipulator based on the hybrid transmission of gear and tendon rope mechanism of the present invention has a simple structure, fewer driving components, and high reliability. It can better adapt to complex working environments and achieve the goal of coordinating humans to complete various complex and dangerous work tasks.

[0039] This invention designs an underactuated manipulator based on a hybrid transmission of gears and tendon-wire mechanisms. It features a simple structure, few driving components, and strong adaptability, aiming to flexibly, stably, and quickly grasp objects of various complex shapes. The underactuated fingers of this adaptive manipulator employ a biomimetic design, consisting of a rotary wrist joint, a condylar MP joint, an intermediate PIP joint, and a distal DIP joint. Utilizing a hybrid transmission of gears and tendons, it possesses the ability to interact between lateral rigidity and lateral flexibility, achieving adaptive envelope grasping and pinching.

[0040] It should be noted that in this article, relational terms such as "first" and "second" are only used to refer to an entity or

[0041] An operation is distinguished from another entity or operation without necessarily requiring or implying any such actual relationship or order between those entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An underactuated manipulator based on a hybrid transmission of gears and tendon-wire mechanisms, characterized in that, include: The floating platform underdrive mechanism (1) includes a tendon rope lifting device fixing frame (14), a tendon rope rising guide tube (15), a tendon rope winding wheel (11), a tendon rope drive motor (12), a floating platform (16), and a first copper column (13). The intermediate connecting mechanism (2) includes an L-shaped fixing frame (24), a base frame 1 (21), a base frame 2 (23), and a second copper column (22). The base frame 1 (21) and the base frame 2 (23) are fixedly connected by the second copper column (22), and the L-shaped fixing frame (24) is fixedly connected to the base frame 2 (23). Finger mechanism (3): includes wrist joint, MP joint (34), proximal phalanx support (341), proximal phalanx (35), PIP joint (37), intermediate phalanx (38), DIP joint (40), and distal phalanx (41).

2. The underactuated manipulator based on a hybrid transmission of gears and tendon ligaments as described in claim 1, characterized in that: The floating platform underdrive mechanism includes a tendon ligament lifting device fixing frame (14), a tendon ligament rising guide tube (15), a tendon ligament winding wheel (11), a tendon ligament drive motor (12), a floating platform (16), and a first copper column (13). The tendon ligament lifting device fixing frame (14) is threaded onto the base frame 1, and the tendon ligament rising guide tube (15) is threadedly fixed in the middle. The floating platform (16) is fitted inside the tendon ligament rising guide tube (15) and can slide up and down. The tendon ligament drive motor (12) and the tendon ligament winding wheel (11) are connected to the tendon ligament winding wheel (12). 11) The first copper column (13) is fixedly installed on the base frame 1 and close to the tendon rope lifting device fixing frame (14). The tendon rope is wound around the wheel (11) and guided to the tendon rope rising guide tube (15). After passing through the tendon rope rising guide tube (15), it passes through the middle hole of the floating platform (16) to realize the control of the floating platform. Then, three tendon ropes are led out from the floating platform and transmitted to the three finger mechanisms respectively. The middle phalanx of the finger mechanism is equipped with a pulley to transmit the tendon rope to the distal phalanx, so as to realize the synchronous control of the tendon rope on the three finger mechanisms.

3. The underactuated manipulator based on a hybrid transmission of gears and tendon ligaments as described in claim 1, characterized in that: The intermediate connection mechanism includes an L-shaped fixing frame (24), a base frame 1 (21), a base frame 2 (23), and a second copper column (22). The base frame 1 (21) is used to connect the upper floating platform underdrive mechanism and provide space for the installation of the wrist joint rotation drive motor (31). The base frame 2 (23) is threadedly connected to the L-shaped fixing frame (24) to connect the lower finger mechanism. The base frame 1 (21) and the base frame 2 (23) are connected and fixed by the second copper column (22).

4. The underactuated manipulator based on a hybrid transmission of gears and tendon ligaments as described in claim 1, characterized in that: The finger mechanism consists of three parts arranged in a 120° circle around the base frame 1, including a wrist joint, an MP joint (34), a proximal phalanx support (341), a proximal phalanx (35), a PIP joint (37), an intermediate phalanx (38), a DIP joint (40), and a distal phalanx (41).

5. An underactuated manipulator based on a hybrid transmission of gears and tendon ligaments as described in claim 4, characterized in that: The wrist joint includes a wrist joint rotation drive motor (31) and a wrist joint rotation shaft (32). One end of the wrist joint rotation shaft (32) is connected to its independent drive motor (31) via a coupling, and the other end is connected to the proximal phalanx support (341). The motor drives the rotation shaft to provide the finger mechanism with the freedom to rotate around the axis.

6. The underactuated manipulator based on a hybrid transmission of gears and tendon ligaments as described in claim 1, characterized in that: The MP joint (34) includes an MP joint drive motor (33), a proximal phalanx support (341), and a bearing (342). The MP joint (34) of the finger is fixed on the proximal phalanx support (341), which is connected to an L-shaped fixing frame (24). The L-shaped fixing frame (24) is then fixedly connected to the base frame 2 (23). This connection part replaces the wrist joint slewing bearing to bear the main load. At the same time, the MP joint (34) is directly controlled by the motor. Thus, the proximal phalanx (35) uses gear transmission as the transmission scheme and utilizes the characteristics of the worm gear reducer to achieve self-locking function, precise pinching, and no hysteresis response.

7. The underactuated manipulator based on a hybrid transmission of gears and tendon ligaments according to claim 1, characterized in that: The PIP joint (37) includes a torsion spring (362), an arc-shaped adjustable limiting device (361), and a rotating shaft (343). To ensure that it is in an open state before grasping and returns to its initial position after the grasping task is completed, a torsion spring (362) is installed at its joint, and a limiting device is designed: an arc-shaped adjustable limiting device (361). One end of the middle phalanx (38) is connected in series with the PIP joint (37), and the other end is designed with a straight groove connected in series with the distal phalanx. At the same time, the middle phalanx (38) is designed with a pulley (381) to guide the tendon cord (39) and ensure the smooth movement of the tendon cord. The distal phalanx (41) is installed in the straight groove, giving it two degrees of freedom: rotation around the DIP joint (40) and sliding along the straight groove, so that it can be transformed from a pinching state to a gripping state. In order to ensure that the distal phalanx returns to its initial position after the grasping task is completed, a torsion spring is also designed at the DIP joint (40). The limiting between the distal phalanx and the middle phalanx is formed by the connection between the back of the distal phalanx and the end protrusion of the middle phalanx. The middle phalanx (38) and the distal phalanx (41) are transmitted through tendon cords (39). The finger design adopts a rigid structure on the outside as the grasping drive and stable support, and the inside has an adaptive and evenly distributed flexible contact gripping. At the same time, it is assisted by machine vision to judge the shape characteristics of the target object, and then adjust the grasping orientation and posture of the robot arm to automatically adapt to and fit the surface shape of the grasped object, so as to achieve non-destructive and reliable grasping. The tendon cords (39) of the three finger mechanisms arranged in a 120° circle pass through the base frame 1 (21) and converge to the floating platform (16), so that the floating platform (16) can control the opening and closing of the three finger mechanisms at the same time, reducing the number of actuators.

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