Two-degree-of-freedom robot joint, collaborative robot and manipulator

Abstract

The present invention provides a two-degree-of-freedom robot joint, a collaborative robot, and a manipulator. The robot joint includes a first base, a second base connected to the first base via a first rotating portion, a driving portion including a first drive unit and a second drive unit, and a transmission portion including a first transmission assembly and a second transmission assembly. The first motion branch includes a first drive unit, a first transmission assembly, and a second rotating portion and a third rotating portion disposed at both ends of the first transmission assembly. The first motion branch is a planar motion branch. The second rotating portion and the third rotating portion limit the axial rotation of the first transmission assembly, and the first transmission assembly is only subjected to tension and pressure, thereby eliminating the need for a guide member. The second motion branch includes a second drive unit, a second transmission assembly, and a fourth rotating portion connected to the second base. The first motion branch and the second motion branch move independently, achieving decoupling of pitch motion and roll motion and simplifying motion control.

Description

Technical Field

[0001] The present invention belongs to the technical field of robots, and in particular relates to a two-degree-of-freedom robot joint, a collaborative robot and a manipulator. Background Art

[0002] Two-degree-of-freedom robot joints typically use two single-degree-of-freedom joints connected in series to achieve pitch and roll motion. This tandem direct-drive approach is bulky, with the center of gravity close to the moving joints, resulting in high inertia and difficulty achieving human-like ball-joint motion, resulting in a low degree of anthropomorphism. Ball joints are a commonly used joint for spatial motion in robots, but they have a limited range of motion and are difficult to drive directly with motors. To achieve ball-joint-like motion, some use arc-shaped guide rails as an alternative to ball joints, but these are larger and have a smaller range of motion. Some use wire ropes to drive ball joints, but this suffers from low precision and insufficient rigidity. Some use complex kinematic mechanisms to drive ball joints, but this is complex and takes up a lot of space. Summary of the Invention

[0003] The purpose of the present invention is to provide a two-degree-of-freedom robot joint, a collaborative robot and a manipulator, which can simultaneously realize the pitch motion and lateral swing motion of the joint through parallel drive. The robot joint of this scheme can simulate the ball-like joint motion of the human body and has the advantages of small size, large load, low inertia and high stiffness.

[0004] In order to solve the above technical problems, the present invention can adopt the following technical solutions: a two-degree-of-freedom robot joint, comprising a first base extending along the Z-axis direction, a second base rotatably connected to the first base through a first rotating part, a driving part for providing power, and a transmission part for transmitting power, the driving part comprising a first driving unit and a second driving unit, the transmission part comprising a first transmission assembly for transmitting the power of the first driving unit and a second transmission assembly for transmitting the power of the second driving unit, one end of the first transmission assembly is connected to the second base through the second rotating part, and the other end is connected to the first base through the third rotating part, the first rotating part, the second rotating part and the third rotating part are each formed as a universal joint assembly to limit the axial rotation of the first transmission assembly; the first transmission assembly comprises a first linear motion member and a first transmission rod, the first linear motion member is used to convert the rotational motion of the first driving unit into a first linear motion in the YZ plane, the first transmission rod is used to transmit the first linear motion, and the first transmission rod is a hollow rod at least partially arranged on the outer periphery of the first linear motion member.

[0005] Furthermore, the first linear motion member includes a first lead screw and a first nut that cooperate with each other, the first transmission rod and the first nut are fixedly installed, the first transmission rod is connected to the X-axis of the second rotating part, and when the first driving unit is driven, the first nut drives the first transmission rod to move axially along the outer periphery of the first lead screw to drive the second rotating part.

[0006] Furthermore, the second transmission assembly is connected to the second base through a fourth rotating part, and the second transmission assembly includes a second linear motion member and a second transmission rod. The second linear motion member is used to convert the rotational motion of the second drive unit into a second linear motion along the Z-axis direction. When the first drive unit is driven, the second base rotates around the X-axis of the first rotating part to perform the first rotational motion; when the second drive unit is driven, the second base rotates around the Y-axis of the first rotating part to perform the second rotational motion.

[0007] Furthermore, the second transmission assembly is arranged below the first transmission assembly, the X axes of the first rotating part and the fourth rotating part are coaxially arranged, and the X axes of the first rotating part and the second rotating part are parallel and the Y axes are coaxially arranged.

[0008] Furthermore, the first rotating part and the second rotating part are arranged on the end surface of the second base, and the fourth rotating part is arranged on the side surface of the second base.

[0009] Furthermore, the second linear motion member includes a second lead screw, a second nut, a nut seat and a guide member, the second lead screw and the second nut cooperate with each other, the nut seat is fixed to the second nut and moves along the guide member, one end of the second transmission rod is connected to the Y-axis of the fourth rotating part, and the other end is axially rotatably connected to the nut seat through the fifth rotating part.

[0010] Furthermore, the first drive unit is fixedly connected to the first base, the third rotating part includes a third rotating part support rotatably connected to the first base, and the output shaft of the first drive unit is coaxially connected to the third rotating part support; the second drive unit is fixedly connected to the first base, and the second screw is coaxially connected to the output shaft of the second drive unit through a screw connecting shaft, and the screw connecting shaft passes through the first base to be fixed to the second screw.

[0011] The present invention can also adopt the following technical solution: a collaborative robot, comprising a base, an upper arm, a lower arm, a shoulder joint connecting the upper arm and the base, an elbow joint connecting the upper arm and the lower arm, and a wrist joint connected to the end of the lower arm, wherein at least one of the shoulder joint and the wrist joint includes any of the two-degree-of-freedom robot joints described above.

[0012] The present invention may also adopt the following technical solution: a robotic arm comprising a palm and a plurality of fingers connected to the palm, wherein the fingers are connected to the palm via base joints, and the base joints are formed as any one of the two-degree-of-freedom robot joints described above.

[0013] Compared with the prior art, the beneficial effects of the specific embodiments of the present invention are at least the following: 1. A two-degree-of-freedom parallel drive method is used to simulate the active pitching motion and lateral swinging motion of a ball-like joint, and the robot joint flexibility is better; 2. The asymmetric two-active branch parallel mechanism can realize the decoupling of pitching motion and lateral swinging motion, reducing the difficulty of motion control; 3. The first motion branch is a planar motion. By adjusting the first transmission component and the connection relationship, the first transmission component does not need to be provided with a guide part, which simplifies the structure of the first transmission component; 4. By adjusting the joint drive and transmission structure distribution, the robot joint structure is made compact. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of a robot joint according to an embodiment of the present invention;

[0015] Figure 2 yes Figure 1 A cross-sectional view of the robot joint is shown;

[0016] Figure 3 is a schematic diagram of a robot joint performing a first rotational motion according to an embodiment of the present invention;

[0017] Figure 4 is a schematic diagram of a robot joint performing a second rotational motion according to an embodiment of the present invention;

[0018] Figure 5 is a schematic diagram of a robot joint performing a third rotational motion according to an embodiment of the present invention;

[0019] Figure 6 yes Figure 1 A partial cross-sectional view of the robot joint is shown. DETAILED DESCRIPTION

[0020] In order to make the technical solution of the present invention clearer, the embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the specific description of the implementation mode is only used to teach those skilled in the art how to implement the present invention, rather than to exhaustively list all feasible ways of the present invention, nor to limit the specific scope of implementation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should fall within the scope of protection of the present invention.

[0021] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0022] Those skilled in the art will understand that when we refer to an element as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there can be intervening elements. In addition, "connected" or "coupled" as used herein can include wireless connections or couplings. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0024] The specific embodiment of the present invention protects a two-degree-of-freedom robot joint, Figure 1 , including a first base 10, a second base 20, a driving part, and a transmission part. The first base 10 extends along the Z-axis direction (joint axial direction), and the second base 20 is rotatably connected to the first base 10 through a first rotating part 51; the driving part is used to provide power, and the transmission part is used to transmit power. The driving part includes a first driving unit 31 and a second driving unit 32. Correspondingly, the transmission part includes a first transmission assembly for transmitting power to the first driving unit 31, and a second transmission assembly for transmitting power to the second driving unit 32.

[0025] One end of the first transmission assembly is connected to the second base 20 via a second rotating portion 52, and the other end is connected to the first base 10 via a third rotating portion 53. The end of the first transmission assembly connected to the third rotating portion 53 is used to receive power from the first drive unit 31. When the first drive unit 31 is driven, the first transmission assembly drives the second base 20 to rotate via the second rotating portion 52. Specifically, the first transmission assembly includes a first linear motion member 410 and a first transmission rod 411. The first linear motion member 410 is used to convert the rotational motion of the first drive unit 31 into a first linear motion in the YZ plane. The first transmission rod 411 is used to transmit the first linear motion. The first transmission rod 411 is a hollow rod at least partially disposed on the outer periphery of the first linear motion member 410. The first rotating portion 51, the second rotating portion 52, and the third rotating portion 53 form a universal joint assembly.

[0026] Further, refer to Figure 2 The first linear motion member 410 includes a first lead screw 4021 and a first nut 4031 that cooperate with each other. The first nut 4031 is sleeved on the first lead screw 4021. The lead screw and nut mechanism including the first lead screw 4021 and the first nut 4031 can convert the rotational motion of the first drive unit 31 into a first linear motion. The first transmission rod 411 and the first nut 4031 are fixedly installed to transmit the first linear motion. Exemplarily, the first transmission rod 411 and the first nut 4031 are fixedly installed by threaded cooperation.

[0027] Specifically, Figure 3 When the first driving unit 31 is driven, the first linear motion member 410 converts the rotational motion of the first driving unit 31 into a first linear motion in the YZ plane. The first transmission rod 411 is fixed to the first nut 4031. When the first nut 4031 moves along the axial direction of the first screw 4021, the first nut 4031 drives the first transmission rod 411 to move axially along the outer periphery of the first screw 4021 to move the second rotating part 52. The first transmission rod 411 is connected to the X-axis of the second rotating part 52.

[0028] The above scheme simplifies the design of the first transmission assembly. Specifically, the first rotating part 51, the second rotating part 52 and the second base 20 can limit the rotation of the first transmission rod 411 around the Z-axis direction, and thus can limit the axial rotation of the first nut 4031, that is, the first rotating part 51 and the second rotating part 52 are formed into a universal joint assembly. For example, the universal joint assembly can realize rotation around the X-axis direction and around the Y-axis direction respectively, and thus can limit the axial rotation of the first nut 4031; in addition, similarly, the second rotating part 52 and the third rotating part 53 adopt the design of a universal joint assembly, which can make the first screw 4021 only subject to axial tension and pressure, thereby eliminating the need for a guide rod or guide rail as a guide to cooperate with the movement of the first screw 4021, thereby eliminating the need for a guide member in the first transmission assembly to limit the rotation of the first nut 4031 and the axial force of the first screw 4021, thereby simplifying the design of the first transmission assembly.

[0029] Ginseng Figure 1-Figure 2 The second transmission assembly is connected to the second base 20 via the fourth rotating portion 54. When the second driving unit 32 is driven, the second transmission assembly drives the second base 20 to rotate via the fourth rotating portion 54. The second transmission assembly includes a second linear motion member 420 and a second transmission rod 421. One end of the second transmission rod 421 is connected to the second base 20 via the fourth rotating portion 54, and the other end is axially rotatably connected to the second linear motion member 420 via a fifth rotating portion 55.

[0030] Specifically, the robot joint includes two active motion branches, the first motion branch includes the first drive unit 31, the first transmission assembly, the second rotating part 52 and the third rotating part 53, and the second motion branch includes the second drive unit 32, the second transmission assembly, the fourth rotating part 54 and the fifth rotating part 55. The first motion branch and the second motion branch are vertically distributed and arranged in parallel.

[0031] Ginseng Figure 2-Figure 3 , the first transmission rod 411 is arranged on the outer periphery of the first linear motion member 410, that is, the first transmission rod 411 at least partially surrounds the first linear motion member 410 from the circumferential direction. When the first driving unit 31 is driven, the first linear motion member 410 converts the rotational motion of the first driving unit 31 into the first linear motion. The first transmission rod 411 is connected to the X-axis of the second rotating part 52. The first transmission rod 411 transmits the first linear motion to move the second rotating part 52 along the YZ plane, so that the second base 20 rotates around the X-axis of the first rotating part 51 to perform the first rotational motion; Figure 4One end of the second transmission rod 421 is connected to the Y-axis of the fourth rotating portion 54, and the other end is connected to the fifth rotating portion 55. When the second drive unit 32 is driven, the second linear motion member 420 converts the rotational motion of the second drive unit 32 into a second linear motion. The second transmission rod 421 transmits the second linear motion to move the fourth rotating portion 54 along the XZ plane, causing the second base 20 to rotate about the Y-axis of the first rotating portion 51 to perform a second rotational motion. Exemplarily, the first rotational motion is a pitch motion, and the second rotational motion is a yaw motion.

[0032] Ginseng Figure 5 When both the first driving unit 31 and the second driving unit 32 are driven, the first transmission assembly moves the second rotating part 52 so that the second base 20 rotates around the X-axis of the first rotating part 51, and the second transmission assembly moves the fourth rotating part 54 so that the second base 20 rotates around the Y-axis of the first rotating part 51. Therefore, the robot joint performs a third rotational motion, which is a composite motion of the first rotational motion and the second rotational motion. The third rotational motion realizes the ball-like joint motion of the robot joint, so that the robot joint has a better anthropomorphic effect.

[0033] Specifically, Figure 2 The second linear motion member 420 includes a second lead screw 4022, a second nut 4032, a guide member 405, and a nut seat 404. The second lead screw 4022 and the second nut 4032 cooperate with each other. The nut seat 404 is fixed to the second nut 4032 and connected to the guide member 405. When the second drive unit 32 is driven, the nut seat 404 drives the second nut 4032 along the guide member 405, and the second linear motion member 420 generates a second linear motion. One end of the second transmission rod 421 is connected to the Y-axis of the fourth rotating portion 54, and the other end is rotatably connected to the nut seat 404 via the fifth rotating portion 55. The fifth rotating portion 55 is formed as a spherical bearing. The first motion branch is a planar motion branch, and the first motion branch moves in the YZ plane; the second motion branch is a spatial motion branch, and when the robot joint performs the second rotational motion, the second motion branch moves in the XZ plane; when the robot joint performs the third rotational motion, the second motion branch generates spatial motion, and the spherical bearing provides the degrees of freedom required for the spatial motion of the second branch.

[0034] Through the above-mentioned first motion branch chain and second motion branch chain, the robot joint can realize active pitch motion and active side swing motion, the joint flexibility is good, and at the same time it can simulate the ball joint motion of the human body, and the joint has a high degree of anthropomorphism.

[0035] Furthermore, the first drive unit 31 and the second drive unit 32 are arranged at one end of the first base 10, and the second base 20 is arranged at the other end of the first base 10 along the Z-axis direction. The first base 10 and the second base 20 are able to rotate relative to each other through the first rotating part 51. The first base 10 is a fixed structural component, and the second base 20 is a movable structural component.

[0036] Exemplarily, the second drive unit 32 is disposed below the first drive unit 31, and the second transmission assembly is disposed below the first transmission assembly, so that the first motion branch and the second motion branch are disposed in parallel along the Y-axis direction. The X-axis of the first rotating part 51 and the fourth rotating part 54 are coaxially disposed, and the X-axis of the first rotating part 51 and the second rotating part 52 are parallel and coaxially disposed. This makes the robot joint occupy a smaller space in the X-axis direction (width direction) and the structural distribution more compact. Specifically, the first rotating part 51 and the second rotating part 52 are disposed on the end surface of the second base 20, and the fourth rotating part 54 is disposed on the side of the second base 20. When the first transmission rod 411 moves the second rotating part 52, the second base 20 rotates about the X-axis of the first rotating part 51. When the second transmission rod 421 moves the fourth rotating part 54, the second base 20 rotates about the Y-axis of the first rotating part 51. When the robot joint performs the first rotational motion and the second rotational motion, the first motion branch and the second motion branch adopt an asymmetric structural setting, realizing motion decoupling and reducing the difficulty of control.

[0037] In a specific embodiment, Figure 6, one end of the first transmission assembly is connected to the second base 20 through the second rotating part 52, and the other end is connected to the first base 10 through the third rotating part 53. One end of the second transmission assembly is connected to the second base 20 through the fourth rotating part 54, and the other end is connected to the first base 10. Specifically, as mentioned above, the first driving unit 31 is fixed to the first base 10, and the third rotating part 53 includes a third rotating part support 531. The output shaft 311 of the first driving unit is coaxially connected to the third rotating part support 531 through a D-shaped hole, and at the same time serves as the supporting shaft of the third rotating part support 531. The third rotating part support 531 is connected to the first base 10 through components such as thrust ball bearings and deep groove ball bearings, and bears the axial load transmitted by the first screw 4021 through the thrust ball bearings, and bears the radial load transmitted by the first screw 4021 through the deep groove ball bearings; the second driving unit 32 is fixedly connected to The first base 10, the second screw 4022 of the second linear motion member 420 is connected to the output shaft 321 of the second drive unit through the screw connecting shaft 4023, the screw connecting shaft 4023 and the output shaft 321 of the second drive unit are coaxially connected through a D-shaped hole, the output shaft 321 of the second drive unit also serves as the support shaft of the screw connecting shaft 4023, the screw connecting shaft 4023 is fixedly connected to the second screw 4022 of the second linear motion member 420, compared with the traditional method of using a coupling, this connection method can withstand a larger axial load, is simpler in structure and has a better structural support effect.

[0038] The preferred embodiment of the above scheme provides a two-degree-of-freedom robot joint, which can realize active pitch motion and active roll motion, and the pitch motion and roll motion are decoupled, which reduces the difficulty of motion control. At the same time, it can realize ball-like joint motion, and the joint has good flexibility and high degree of anthropomorphism. By improving the structure of the first transmission component, the first transmission component does not need to be provided with a guide part, thereby simplifying the structure of the first transmission component. In addition, through the position distribution of the driving part and the transmission part of the robot joint, the joint structure is further made compact and easy to distribute.

[0039] The present invention also provides a collaborative robot comprising a base, an upper arm, a lower arm, a shoulder joint connecting the base and the upper arm, an elbow joint connecting the upper arm and the lower arm, and a wrist joint connected to the end of the lower arm, wherein at least one of the elbow joint and the wrist joint comprises any of the two-degree-of-freedom robot joints described above. Compared to conventional collaborative robots that employ multiple single-degree-of-freedom joints in series, the collaborative robot in this solution employs two-degree-of-freedom joints in a parallel structure, which has the advantages of being compact, capable of carrying large loads, having low inertia, and having high rigidity.

[0040] The present invention is also used to provide a robotic arm, including a palm and multiple fingers connected to the palm, wherein the fingers are connected to the palm through base joints and achieve movement relative to the palm, and the base joints are formed as any of the two-degree-of-freedom robot joints described above, so that the base joints have active pitch and active roll degrees of freedom, and have good flexibility.

[0041] Finally, it should be noted that due to the limitations of textual expression, the above description is merely illustrative and not exhaustive. The present invention is not limited to the disclosed embodiments. Without departing from the scope and spirit of the above examples, improvements and modifications may be made by those skilled in the art, and such improvements and modifications should also be considered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A two-degree-of-freedom robot joint, characterized in that: The invention comprises a first base extending in the Z-axis direction, a second base rotatably connected to the first base through a first rotating part, a driving part providing power, and a transmission part transmitting power, wherein the driving part comprises a first driving unit and a second driving unit, and the transmission part comprises a first transmission assembly for transmitting power to the first driving unit and a second transmission assembly for transmitting power to the second driving unit, one end of the first transmission assembly is connected to the second base through the second rotating part, and the other end is connected to the first base through the third rotating part, the first rotating part, the second rotating part and the third rotating part are each formed as a universal joint assembly to limit the first transmission assembly from spinning in the axial direction; the first transmission assembly comprises a a linear motion member and a first transmission rod, wherein the first linear motion member is used to convert the rotational motion of the first drive unit into a first linear motion in the YZ plane, and the first transmission rod is used to transmit the first linear motion, and the first transmission rod is a hollow rod at least partially disposed on the outer periphery of the first linear motion member; a second transmission assembly is connected to the second base via a fourth rotating portion, the second transmission assembly includes a second linear motion member and a second transmission rod, and the second linear motion member is used to convert the rotational motion of the second drive unit into a second linear motion along the Z-axis direction. When the first drive unit is driven, the second base rotates about the X-axis of the first rotating portion to perform the first rotational motion; When the second driving unit is driven, the second base rotates around the Y-axis of the first rotating part to perform a second rotational motion; the second transmission assembly is arranged below the first transmission assembly, the X-axis of the first rotating part and the fourth rotating part are coaxially arranged, the X-axis of the first rotating part and the second rotating part are parallel, and the Y-axis is coaxially arranged; the first rotating part and the second rotating part are arranged on the end face of the second base, and the fourth rotating part is arranged on the side of the second base; the second linear motion part includes a second lead screw, a second nut, a nut seat and a guide member, the second lead screw and the second nut cooperate with each other, the nut seat is fixed to the second nut and moves along the guide member, one end of the second transmission rod is connected to the Y-axis of the fourth rotating part, and the other end is axially rotatably connected to the nut seat through the fifth rotating part.

2. The two-degree-of-freedom robot joint according to claim 1, characterized in that: The first linear motion member includes a first lead screw and a first nut that cooperate with each other. The first transmission rod and the first nut are fixedly installed. The first transmission rod is connected to the X-axis of the second rotating part. When the first driving unit is driven, the first nut drives the first transmission rod to move axially along the outer periphery of the first lead screw to drive the second rotating part.

3. The two-degree-of-freedom robot joint according to claim 2, characterized in that: The first drive unit is fixedly connected to the first base, the third rotating part includes a third rotating part support rotatably connected to the first base, and the output shaft of the first drive unit is coaxially connected to the third rotating part support; the second drive unit is fixedly connected to the first base, and the second screw is coaxially connected to the output shaft of the second drive unit through a screw connecting shaft, and the screw connecting shaft passes through the first base to be fixed to the second screw.

4. A collaborative robot, characterized in that: It includes a base, an upper arm, a lower arm, a shoulder joint connecting the upper arm and the base, an elbow joint connecting the upper arm and the lower arm, and a wrist joint connected to the end of the lower arm, wherein at least one of the shoulder joint and the wrist joint includes the two-degree-of-freedom robot joint described in any one of claims 1-3.

5. A robot, characterized in that: The robot comprises a palm and a plurality of fingers connected to the palm, wherein the fingers are connected to the palm via base joints, and the base joints are formed as the two-degree-of-freedom robot joints according to any one of claims 1 to 3.

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