Under-actuated knuckle structure based on piezoelectric motor

Abstract

The utility model discloses an under-actuated finger joint structure based on piezoelectric motors. The under-actuated finger joint structure comprises a first finger joint assembly, a second finger joint assembly and a third finger joint assembly. A piezoelectric motor unit is arranged on the first knuckle assembly, and the output end of the piezoelectric motor unit is connected with the second knuckle assembly through a first transmission unit; one end of the second knuckle assembly is connected with the first transmission unit through a second transmission unit, and the other end of the second knuckle assembly is provided with a third transmission unit connected with the third knuckle assembly. The third finger joint assembly is provided with a fourth transmission unit connected with the third transmission unit. The piezoelectric motors are adopted to drive the first finger joint assembly, the second finger joint assembly and the third finger joint assembly which form the under-actuated system, the number of driving devices is reduced, the structure is more compact, precision and flexibility are effectively improved, manufacturing difficulty is lowered, errors in the assembling process are reduced, and production efficiency is improved. And the consistency and the reliability of the product are improved.

Description

Technical Field

[0001] This utility model relates to the field of robotic arms, and in particular to an underactuated finger joint structure based on a piezoelectric motor. Background Technology

[0002] Industrial robots, or multi-jointed manipulators or multi-degree-of-freedom robots, are designed for industrial applications. They can automatically perform tasks, relying on their own power and control capabilities to achieve various functions. The robot's end effector is a key component for grasping, clamping, and lifting objects. Its adaptability and flexibility are crucial. While traditional dedicated grippers are simple to manufacture, easy to control, have high load capacity, and high reliability, they are only suitable for a small number of objects of specific shapes, lack versatility, and cannot meet the requirements of multi-tasking and high adaptability.

[0003] In this context, driven by anthropomorphic design, multi-jointed, multi-fingered dexterous hands have become a development trend for robotic end effectors. These multi-jointed, multi-fingered hands offer the advantage of strong shape adaptability, enabling them to meet the needs of various tasks. In the research and application of multi-fingered robotic hands, the fingers are typically constructed by connecting several joints in series, with a driver and sensor for each degree of freedom. This results in an excessive number of driving components, complex control, reduced flexibility and controllability, and increased development costs.

[0004] Therefore, it is essential to study how to resolve the contradictions between the number of degrees of freedom, drive method, weight, flexibility, grasping ability, and reliability of a robotic arm, and to research a robotic arm with a simple structure and easy manufacturing based on the underactuated principle. Utility Model Content

[0005] The purpose of this invention is to provide an underactuated finger joint structure based on a piezoelectric motor to solve the problems existing in the prior art.

[0006] The above-mentioned technical objective of this utility model is achieved through the following technical solution:

[0007] An underactuated finger joint structure based on a piezoelectric motor, including

[0008] The first finger joint assembly has a first finger joint, on which a piezoelectric motor unit is provided. The output end of the piezoelectric motor unit is connected to the second finger joint assembly through a first transmission unit.

[0009] The second finger joint assembly has a second finger joint, one end of which is connected to the first transmission unit via a second transmission unit, and the other end of which is provided with a third transmission unit connected to the third finger joint assembly.

[0010] The third finger joint assembly has a third finger joint, on which a fourth transmission unit is provided for connection with the third transmission unit.

[0011] Furthermore, the first finger joint has a first receiving cavity inside, and a set of first shaft hole connectors are provided at the side end of the first finger joint near the second finger joint.

[0012] Furthermore, the piezoelectric motor unit includes a piezoelectric motor, and a gearbox is provided at the output end of the piezoelectric motor. The output end of the gearbox is connected to the first transmission unit through an output gear.

[0013] Furthermore, the first transmission unit includes a first rotating shaft, on which a transmission gear is provided that is connected to the output gear, and at both ends of the first rotating shaft are a first bearing and a first pulley.

[0014] Furthermore, the second finger joint has a second receiving cavity inside, a second shaft hole connector is provided at one end of the second finger joint, and a set of third shaft hole connectors is provided at the other end of the second finger joint.

[0015] Furthermore, the second transmission unit includes a second rotating shaft, with a second bearing, a second pulley, and a third pulley respectively provided at both ends of the second rotating shaft, and a third bearing provided at the middle position of the second rotating shaft.

[0016] Furthermore, the third transmission unit includes a third rotating shaft, with a fourth bearing, a fourth pulley, and a fifth pulley respectively provided at both ends of the third rotating shaft.

[0017] Furthermore, the third finger joint is provided with a fourth shaft hole connector on the side end near the second finger joint.

[0018] Furthermore, the fourth transmission unit includes a fourth rotating shaft, with a fifth bearing and a sixth pulley respectively at both ends of the fourth rotating shaft, and a sixth bearing at the middle position of the fourth rotating shaft.

[0019] Furthermore, the first transmission unit, the second transmission unit, the third transmission unit, and the fourth transmission unit are driven by double tendon ropes.

[0020] In summary, this utility model has the following beneficial effects:

[0021] By using piezoelectric motors to drive the first, second, and third finger joint components that constitute the underactuated system, the number of drive devices is reduced, making the entire finger joint structure more compact and simple. Precision and flexibility are effectively improved, which not only reduces manufacturing difficulty but also reduces errors in the assembly process, thereby improving product consistency and reliability.

[0022] The joint components are all connected by double tendon rope transmission, which delays the problem of reduced transmission accuracy caused by the wear and tear of traditional single tendon rope due to long-term friction with pulleys and other components, which leads to a thinner tendon rope diameter and changes in surface roughness. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the underactuated finger joint structure based on a piezoelectric motor described in this utility model.

[0024] Figure 2 This is a schematic diagram of the finger joint assembly described in this utility model.

[0025] Figure 3 This is a schematic diagram of the transmission unit described in this utility model.

[0026] Figure 4 This is a schematic diagram of the piezoelectric motor unit and the first transmission unit described in this utility model.

[0027] Figure 5 This is a top view of the transmission unit described in this utility model. Detailed Implementation

[0028] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with the illustrations and specific embodiments.

[0029] like Figures 1 to 5 As shown, the present invention proposes an underactuated finger joint structure based on a piezoelectric motor, comprising a first finger joint assembly 1, a second finger joint assembly 2, and a third finger joint assembly 3 constituting an underactuated system.

[0030] The first finger joint assembly 1 has a first finger joint 11, and a piezoelectric motor unit 12 is provided on the first finger joint 11. The output end of the piezoelectric motor unit 12 is connected to the second finger joint assembly 2 through a first transmission unit 13.

[0031] The second finger joint assembly 2 has a second finger joint 21. One end of the second finger joint 21 is connected to the first transmission unit 13 via a second transmission unit 22, and the other end of the second finger joint 21 is provided with a third transmission unit 23 connected to the third finger joint assembly 3.

[0032] The third finger joint assembly 3 has a third finger joint 31, on which a fourth transmission unit 32 connected to the third transmission unit 23 is provided.

[0033] The underactuated finger joint structure of this application only needs to set a piezoelectric motor unit 12 on the first finger joint component 1 to realize the underactuated coordinated movement of each joint. Through the matching design of the tendon rope length ratio and the pulley diameter, the precise proportional distribution of the movement amplitude of each joint can be achieved.

[0034] Example 1

[0035] In this embodiment, the first finger joint 11 has a first receiving cavity 111 inside, which is used to install the piezoelectric motor unit 12 and the first transmission unit 13.

[0036] Traditional knuckle structures typically use electromagnetic motors as the driving source. However, electromagnetic motor drive structures are large and heavy, have slow response speeds, and generate interference during operation, making them unsuitable for use in environments with strict electromagnetic requirements.

[0037] In this embodiment, the piezoelectric motor unit 12 adopts a piezoelectric motor 121, which uses the inverse piezoelectric effect to convert electrical energy into mechanical energy. The piezoelectric motor 121 has higher precision than the electromagnetic motor. The piezoelectric motor 121 has lower torque. When used in conjunction with the gearbox 113, the knuckle structure not only improves the gripping force but also the gripping accuracy.

[0038] In this embodiment, the piezoelectric motor 121 is fixedly mounted on the through hole in the side wall of the first receiving cavity 111. The output end of the piezoelectric motor 121 extends into the first receiving cavity 111. A gearbox 113 is provided at the output end of the piezoelectric motor 121. After the piezoelectric motor 121 is energized, it outputs high-speed, low-torque rotation. After being amplified by the gearbox 113, it is converted into the precise torque required to drive the joint. An output gear 114 is provided at the output end of the gearbox 113. The output gear 114 and the first transmission unit 13 are driven through a meshing structure to form a power output mechanism.

[0039] In this embodiment, the first transmission unit 13 includes a first rotating shaft 131. The two ends of the first rotating shaft 131 are respectively mounted on another set of side wall through holes of the first receiving cavity 111 through a first bearing 133. A transmission gear 132 that meshes and transmits with the piezoelectric motor unit 12 is sleeved in the middle position of the first rotating shaft 131 to realize the transmission connection with the piezoelectric motor unit 12 and obtain the driving force of the piezoelectric motor 121.

[0040] Traditional finger joint drive structures mostly transmit power through a single tendon chord. However, prolonged friction between the tendon chord and components like pulleys causes wear, resulting in a thinner diameter and altered surface roughness. This not only exacerbates elastic deformation but can also cause slippage in the tendon chord's transmission through the pulley, further reducing transmission accuracy and shortening the tendon chord's lifespan.

[0041] Therefore, in this embodiment, two first pulleys 134 are also provided on the first rotating shaft 131. A tendon rope 4 is provided on each of the first pulleys 134. One end of the tendon rope 4 is sleeved on the first pulley 134, and the other end of the tendon rope 4 is sleeved on the pulley corresponding to the second transmission unit 22. In this embodiment, the power transmission between the first finger joint assembly 1 and the first finger joint assembly 2 is realized through two sets of tendon rope systems. It can also alleviate the wear of the tendon rope 4 and avoid the problem of reduced transmission accuracy caused by the wear of the tendon rope 4.

[0042] In this embodiment, the first finger joint 11 has a first shaft hole connector 112 at its side end near the second finger joint 21, and the first shaft hole connector 112 has a shaft hole. Correspondingly, a second shaft hole connector 212 is also provided at the end of the second finger joint 21 near the first finger joint 11, and the second shaft hole connector 212 also has a shaft hole. In this embodiment, a set of first shaft hole connectors 112 are provided, which are arranged opposite each other at the side end of the first finger joint 11. The second shaft hole connectors 212 are pre-positioned by inserting two first shaft hole connectors 112 to align their shaft holes.

[0043] The second transmission unit 22 in this embodiment includes a second rotating shaft 221. The two ends of the second rotating shaft 221 are respectively installed in the shaft holes of the first shaft hole connector 112 through a second bearing 222. The middle position of the second rotating shaft 221 is installed in the shaft hole of the second shaft hole connector 212 through a third bearing 225. Two sets of second pulleys 223 and third pulleys 224 are symmetrically arranged on the second rotating shaft 221. One set of second pulleys 223 is connected to the first pulley 134 of the first finger joint assembly 1 through a tendon rope 4. The other set of third pulleys 224 is connected to the third transmission unit 23 through a tendon rope 4 to achieve double tendon rope connection.

[0044] In this embodiment, the third transmission unit 23 is disposed within the second receiving cavity 211 within the second finger joint 21. The third transmission unit 23 includes a third rotating shaft 231, and both ends of the third rotating shaft 231 are respectively mounted on the side wall through holes of the second receiving cavity 211 via a fourth bearing 232. Similarly, two sets of fourth pulleys 233 and fifth pulleys 234 are symmetrically arranged on the fourth bearing 232. One set of fourth pulleys 233 is connected to the second transmission unit 22 via double tendon ropes, and the other set of fifth pulleys 234 is connected to the fourth transmission unit 22 via double tendon ropes.

[0045] In this embodiment, a third shaft hole connector 213 is provided on the side of the second finger joint 21 near the third finger joint 31, and a fourth shaft hole connector 311 is provided on the side end of the third finger joint 31 near the second finger joint 21. The structure and engagement method of the third shaft hole connector 213 and the fourth shaft hole connector 311 are the same as those of the first shaft hole connector 112 and the second shaft hole connector 212 described above, so they will not be described in detail here.

[0046] The fourth transmission unit 32 includes a fourth rotating shaft 321, which passes through the shaft holes on the third shaft hole connector 213 and the fourth shaft hole connector 311 in sequence. The two ends of the fourth rotating shaft 321 are respectively positioned and installed by a fifth bearing 322, and the middle position of the fourth rotating shaft 321 is positioned and installed by a sixth bearing 324. A set of sixth pulleys 323 is also provided on the fourth rotating shaft 321, which is connected to the fifth pulley 234 of the third transmission unit 23 by double tendon rope.

[0047] In this document, the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer", "vertical", and "horizontal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the purpose of clarifying the technical solution and for the convenience of description, and therefore should not be construed as limiting the present utility model.

[0048] In this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. An underactuated finger joint structure based on a piezoelectric motor, characterized in that, include A first finger joint assembly (1) includes a first finger joint (11), on which a piezoelectric motor unit (12) is provided, the output end of which is connected to a first transmission unit (13) and a second transmission unit (22). Connected to the second finger joint assembly (2); The second finger joint assembly (2) has a second finger joint (21), one end of which is connected to the first transmission unit (13) via a second transmission unit (22), and the other end of which is provided with a third transmission unit (23) connected to the third finger joint assembly (3). The third finger joint assembly (3) has a third finger joint (31) and a fourth transmission unit (32) connected to the third transmission unit (23) on the third finger joint (31).

2. The underactuated finger joint structure based on a piezoelectric motor according to claim 1, characterized in that, The first finger joint (11) has a first receiving cavity (111) inside, and a set of first shaft hole connectors (112) are provided on the side end of the first finger joint (11) near the second finger joint (21).

3. The underactuated finger joint structure based on a piezoelectric motor according to claim 1, characterized in that, The piezoelectric motor unit (12) includes a piezoelectric motor (121), and a gearbox (113) is provided at the output end of the piezoelectric motor (121). The output end of the gearbox (113) is connected to the first transmission unit (13) through an output gear (114).

4. The underactuated finger joint structure based on a piezoelectric motor according to claim 1, characterized in that, The first transmission unit (13) includes a first rotating shaft (131), on which a transmission gear (132) is provided that is connected to the output gear (114). At both ends of the first rotating shaft (131) are a first bearing (133) and a first pulley (134).

5. The underactuated finger joint structure based on a piezoelectric motor according to claim 1, characterized in that, The second finger joint (21) has a second receiving cavity (211) inside, a second shaft hole connector (212) is provided on one side of the second finger joint (21), and a set of third shaft hole connectors (213) is provided on the other side of the second finger joint (21).

6. The underactuated finger joint structure based on a piezoelectric motor according to claim 1, characterized in that, The second transmission unit (22) includes a second rotating shaft (221), with a second bearing (222), a second pulley (223) and a third pulley (224) respectively at both ends of the second rotating shaft (221), and a third bearing (225) at the middle position of the second rotating shaft (221).

7. The underactuated finger joint structure based on a piezoelectric motor according to claim 1, characterized in that, The third transmission unit (23) includes a third rotating shaft (231), and a fourth bearing (232), a fourth pulley (233) and a fifth pulley (234) are respectively provided at both ends of the third rotating shaft (231).

8. The underactuated finger joint structure based on a piezoelectric motor according to claim 1, characterized in that, The third finger joint (31) is provided with a fourth shaft hole connector (311) at the side end near the second finger joint (21).

9. The underactuated finger joint structure based on a piezoelectric motor according to claim 1, characterized in that, The fourth transmission unit (32) includes a fourth rotating shaft (321), with a fifth bearing (322) and a sixth pulley (323) respectively at both ends of the fourth rotating shaft (321), and a sixth bearing (324) at the middle position of the fourth rotating shaft (321).

10. The underactuated finger joint structure based on a piezoelectric motor according to claim 1, characterized in that, The first transmission unit (13), the second transmission unit (22), the third transmission unit (23) and the fourth transmission unit (32) are driven by double tendon ropes.

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