A three-degree-of-freedom robot joint and manipulator

Abstract

The present invention provides a three-degree-of-freedom robot joint and manipulator, the robot joint comprising: a first base; a second base connected to the first base via a first rotating portion; a drive portion comprising a first drive unit, a second drive unit, and a third drive unit, the first drive unit being used to move the second rotating portion disposed on the second base, the second drive unit being used to move the third rotating portion disposed on the second base, and driving the second base to rotate around the first rotating portion to perform a first rotational motion and / or a second rotational motion by moving the second rotating portion and / or the third rotating portion; a support transmission shaft connected to the third drive unit and connected to the support output shaft via a fourth rotating portion, the third drive unit driving the support output shaft to perform a third rotational motion via the support transmission shaft and the fourth rotating portion, the rotation centers of the first rotating portion and the fourth rotating portion coinciding. The robot joint of a specific embodiment of the present invention has three active degrees of freedom and a large range of motion.

Description

Technical Field

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

[0002] Multi-DOF robot joints are typically implemented by connecting multiple single-DOF joints in series. However, the series direct drive approach is bulky and places the center of gravity close to the moving joints, resulting in large inertia. This significantly limits motion control effectiveness and fails to achieve human-like ball-joint motion, resulting in a low degree of anthropomorphism. To make three-DOF joints more compact, some approaches achieve internal and external rotation by connecting a joint in series with the output of a two-DOF robot joint, but this results in large end-piece dimensions and high inertia. Some adopt a three-DOF parallel mechanism, but this results in a smaller range of motion for the robot joints. Some employ a parallel differential three-DOF gear mechanism, but this is complex and lacks precision. Summary of the Invention

[0003] The purpose of the present invention is to provide a three-degree-of-freedom robot joint and manipulator, which realizes flexion and extension and lateral swing movement of the robot joint through a two-degree-of-freedom parallel mechanism, and transmits the movement and power of the third drive unit to the second base through the middle motion transmission branch chain, thereby realizing three-degree-of-freedom movement of the robot joint. The flexion and extension movement and lateral swing movement have a larger range of movement, and the internal and external rotation movement can rotate freely around the output shaft of the support.

[0004] To solve the above technical problems, the present invention may adopt the following technical solutions: a three-degree-of-freedom robot joint, comprising: a first base extending axially; a second base rotatably connected to the first base through a first rotating part; a driving part providing power, comprising a first driving unit, a second driving unit and a third driving unit, wherein the first driving unit is used to move the second rotating part provided on the second base, and the second driving unit is used to move the third rotating part provided on the second base, and the second base is driven to rotate around the first rotating part to perform the first rotational motion and / or the second rotational motion by moving the second rotating part and / or the third rotating part; a support transmission shaft, connected to the third driving unit and extending axially, the support transmission shaft is connected to the support output shaft through a fourth rotating part, and the third driving unit drives the support output shaft to rotate around the axial direction to perform the third rotational motion through the support transmission shaft and the fourth rotating part, and the rotation centers of the first rotating part and the fourth rotating part coincide.

[0005] Further, when the first driving unit and the second driving unit synchronously move the second rotating part and the third rotating part in the same direction, the second base rotates around the X-axis of the first rotating part to perform a first rotational motion; when the first driving unit and the second driving unit move the second rotating part and the third rotating part in opposite directions, the second base rotates around the Y-axis of the first rotating part to perform a second rotational motion.

[0006] Furthermore, when the first driving unit and the second driving unit asynchronously move the second rotating portion and the third rotating portion in the same direction, the second base performs a composite rotational motion around the first rotating portion that is a combination of the first rotational motion and the second rotational motion.

[0007] Furthermore, the seat output shaft is rotatably connected to the second base, and when the second base performs the first rotational movement and / or the second rotational movement, the support output shaft follows the movement of the second base; when the support output shaft performs the third rotational movement, the support output shaft rotates relative to the second base.

[0008] Furthermore, the support output shaft penetrates the second base in the axial direction to transmit the third rotational motion to the front end of the second base.

[0009] Furthermore, the robot joint includes a first linear motion member that converts the rotational motion of the first drive unit into linear motion, a second linear motion member that converts the rotational motion of the second drive unit into linear motion, a first transmission rod that rotatably connects the first linear motion member and the second rotating part, and a second transmission rod that rotatably connects the second linear motion member and the third rotating part.

[0010] Furthermore, the robot joint includes a first motion branch and a second motion branch, the first motion branch includes a first drive unit, a first linear motion member, a first transmission rod and a second rotating part, the second motion branch includes a second drive unit, a second linear motion member, a second transmission rod and a third rotating part, and the first motion branch and the second motion branch are symmetrically distributed in parallel.

[0011] Furthermore, the robot joint includes a third motion branch, which includes a third drive unit, a support transmission shaft, a fourth rotating part and a support output shaft. The third motion branch is arranged below the first motion branch and the third motion branch, and the third motion branch moves independently of the first motion branch and the second motion branch.

[0012] Furthermore, the driving portion is arranged at one axial end of the first base, and the second base is arranged at the other axial end of the first base.

[0013] Furthermore, the first rotating part and the fourth rotating part are formed as a cross-axis assembly.

[0014] The present invention may also adopt the following technical solution: a robotic arm comprising a palm and robotic fingers connected to the palm via base joints, wherein the base joints are formed as any one of the three-degree-of-freedom robot joints described above.

[0015] Furthermore, the robotic finger includes a first phalanx connected to the base joint, and a second phalanx connected to the first phalanx, the first phalanx includes a third transmission assembly connected to the support output shaft, and the third transmission assembly converts the third rotational motion into a linear motion to enable the second phalanx to flex and extend.

[0016] Compared with the prior art, the beneficial effects of the specific embodiments of the present invention are: 1. Through a two-degree-of-freedom parallel symmetrical motion branch combined with a third motion branch arranged in the middle, the robot joint can realize active pitch motion, lateral swing motion and internal and external rotation motion, and can simulate the spherical rotation effect of the human joint, with good anthropomorphic performance; 2. The drive part is placed at the rear of the robot joint, which is beneficial to reducing the motion inertia of the robot joint; 3. The joint design based on the connecting rod mechanism has high rigidity and high load. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of a three-degree-of-freedom robot joint according to an embodiment of the present invention;

[0018] Figure 2 yes Figure 1 A cross-sectional view of the robot joint along the first drive unit is shown;

[0019] Figure 3 yes Figure 1 A cross-sectional view of the robot joint along the third drive unit is shown;

[0020] Figure 4 is a schematic diagram of a robot joint performing a first rotational motion according to an embodiment of the present invention;

[0021] Figure 5 is a schematic diagram of a robot joint performing a second rotational motion according to an embodiment of the present invention;

[0022] Figure 6 is a schematic diagram of a robot joint performing a compound rotational motion according to an embodiment of the present invention; DETAILED DESCRIPTION

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] The specific embodiment of the present invention protects a three-degree-of-freedom robot joint, Figure 1-3 , comprising a first base 10, a second base 20, and a driving portion. The first base 10 extends in the axial direction (Z-axis direction), and the second base 20 is rotatably connected to the first base 10 via a first rotating portion 51. The first base 10 is a fixed structural component, and the second base 20 is a movable structural component. The second base 20 can rotate relative to the first base about the first rotating portion 51. For example, the "axial direction" is the axial direction of the joint, which is also the Z-axis direction marked in this application.

[0028] The driving part includes a first driving unit 31, a second driving unit 32 and a third driving unit 33. The first driving unit 31 is used to move the second rotating part 52 set on the second base 20, and the second driving unit 32 is used to move the third rotating part 53 set on the second base 20. By moving the second rotating part 52 and / or the third rotating part 53, the first driving unit 31 and the second driving unit 32 drive the second base 20 to rotate around the first rotating part 51 to perform the first rotational motion and / or the second rotational motion.

[0029] Specifically, Figure 4 When the first driving unit 31 and the second driving unit 32 synchronously move the second rotating part 52 and the third rotating part 53 in the same direction, the second base 20 rotates around the first rotating part 51 to perform a first rotational motion. Specifically, the first rotational motion is a flexion-extension motion. Figure 5 When the first driving unit 31 and the second driving unit 32 move the second rotating part 52 and the third rotating part 53 in opposite directions, the second base 20 rotates around the first rotating part 51 to perform a second rotational motion. Specifically, the second rotational motion is a side-swing motion.

[0030] Further, refer to Figure 6 When the first driving unit 31 and the second driving unit 32 move the second rotating part 52 and the third rotating part 53 asynchronously in the same direction, the second base 20 rotates around the first rotating part 51 to perform a compound rotational motion synthesized by the first rotational motion and the second rotational motion. That is, at this time, the second base 20 performs both the first rotational motion and the second rotational motion, presenting the effect of a compound rotational motion.

[0031] Ginseng Figure 1-3 The robot joint 102 includes a support transmission shaft 452, which is disposed on the first base 10 and extends axially. The support transmission shaft 452 is connected to the third drive unit 33 to transmit the rotational motion and power of the third drive unit 33. The support transmission shaft 452 is connected to the support output shaft 451 via the fourth rotating portion 54. The third drive unit 33 drives the support output shaft 451 to rotate axially (in the Z-axis direction) via the support transmission shaft 452 and the fourth rotating portion 54 to perform a third rotational motion (not shown). Specifically, the third rotational motion is an inward and outward rotational motion. The rotational motion of the third drive unit 33 is transmitted to the support transmission shaft 452, which transmits the rotational motion to the support output shaft 451 via the fourth rotating portion 54. The support output shaft 451 can rotate freely along the axial direction with no restriction on the rotation range, thereby expanding the range of motion of the robot joint.

[0032] Specifically, the support transmission shaft 452 is disposed on the first base 10 and extends axially. The support output shaft 451 is connected to the second base 20 and penetrates the second base 20. When the third drive unit 33 is driven, the support output shaft 451 rotates axially to transmit the rotational motion of the third drive unit 33 to the front end of the second base 20. The support output shaft 451 can further connect to the structural components of the robot joint to enable the corresponding structural components to perform axial rotational motion. The fourth rotating portion 54 connects the support transmission shaft 452 and the support output shaft 451 to transmit the rotational motion of the third drive unit 33. The fourth rotating portion 54 is disposed between the first base 10 and the second base 20, and the rotation centers of the first rotating portion 51 and the fourth rotating portion 54 coincide.

[0033] Among them, Figure 4-5 When the second base 20 performs the first rotational motion and / or the second rotational motion, the support output shaft 451 is connected to the second base 20 and moves with the second base 20. When the support output shaft 451 performs the third rotational motion, the support output shaft 451 is rotatably connected to the second base 20 and can rotate relative to the second base 20. It can be understood that when the first drive unit 31 and the second drive unit 32 are driven asynchronously in the same direction, and the third drive unit 33 is in the driving state, the second base 20 performs the first rotational motion and the second rotational motion about the first rotating portion 51, and the support output shaft 451 moves with the second base 20. At the same time, the support output shaft 451 performs the third rotational motion relative to the second base 20. At this time, the robot joint exhibits a composite motion effect of three motions, which can achieve a humanoid spherical motion effect and enhance the degree of anthropomorphism.

[0034] Specifically, the first rotating portion 51 and the fourth rotating portion 54 are each formed as a cross-axis assembly. When the second base 20 performs a first rotational motion, the second base 20 rotates about the X-axis of the first rotating portion 51. The first rotational motion is the pitch motion of the robot joint. When the second base 20 performs a second rotational motion, the second base 20 rotates about the Y-axis of the first rotating portion 51. The second rotational motion is the yaw motion of the robot joint. When the second base 20 rotates about the first rotating portion 51, the rotation center of the fourth rotating portion 54 coincides with the rotation center of the first rotating portion 51, providing corresponding degrees of freedom to accommodate the movement of the second base.

[0035] For example, Figure 2-3The first rotating part 51 is arranged on the outside of the fourth rotating part 54. When the first driving unit 31 and the second driving unit 32 drive the second base 20 to rotate around the first rotating part 51, the first driving unit 31 and the second driving unit 32 drive the second base 20 to rotate around the first rotating part 51 by moving the second rotating part 52 and the third rotating part 53, and the fourth rotating part 54 follows the movement; when the third driving unit 33 drives the support output shaft 451 to rotate, the fourth rotating part 54 rotates around the axial direction, and the support output shaft 451 is connected to the second base 20, and then the movement and power of the third driving unit 33 are transmitted to the second base 20 through the support transmission shaft 452, the fourth rotating part 54 and the support output shaft 451.

[0036] Specifically, when the second base 20 rotates around the first rotating part 51, especially when the second base 20 performs a compound rotational motion, the motion performed by the second base 20 is a spherical motion, and the rotation centers of the first rotating part 51 and the fourth rotating part 54 are coincident to ensure the transmission effect of the rotational motion of the third driving unit.

[0037] The robot joint of the above specific embodiment realizes three-degree-of-freedom active motion of the robot joint through the first drive unit 31, the second drive unit 32 and the third drive unit 33. At the same time, the range of motion is large, which can simulate the spherical motion of the human joint and has good flexibility.

[0038] Specifically, the driving part is arranged at one axial end of the first base 10, and the second base 20 is arranged at the other axial end of the first base 10, wherein the power of the driving part is transmitted to the second base 20 to realize joint movement, that is, the position where the driving part is arranged is away from the moving joint, which is conducive to reducing the inertia of the robot joint.

[0039] Further, refer to Figure 2-4 The robot joint 102 includes a first linear motion member 410 that converts the rotational motion of the first drive unit 31 into linear motion, and a second linear motion member 420 that converts the rotational motion of the second drive unit 32 into linear motion. Exemplarily, the first linear motion member 410 and the second linear motion member 420 adopt the same structural design. The first linear motion member 410 includes a screw 402, a nut 403 sleeved on the screw 402, a nut seat 404 fixed to the nut 403, and a guide member 405 for guiding the movement direction of the nut 403. The first linear motion member 410 and the second linear motion member 420 are arranged on the first base 10. The screw 402 and the nut 403 convert the rotational motion of the first drive unit 31 and the second drive unit 32 into linear motion. The nut seat 404 drives the nut 403 to move along the direction of the guide member 405, and the guide member 405 extends axially.

[0040] Furthermore, the robot joint 102 includes a first transmission rod 411 rotatably connected to the first linear motion member 410 and the second rotating portion 52, and a second transmission rod 421 rotatably connected to the second linear motion member 420 and the third rotating portion 53. Specifically, one end of the first transmission rod 411 is rotatably connected to the nut seat 404 of the first linear motion member 410, and the other end is rotatably connected to the second rotating portion 52. Similarly, one end of the second transmission rod 421 is rotatably connected to the nut seat 404 of the second linear motion member 420, and the other end is rotatably connected to the third rotating portion 53. When the nut seat 404 moves along the guide member 405, motion is transmitted to the second rotating portion 52 via the first transmission rod 411, and power is transmitted to the third rotating portion 53 via the second transmission rod 421.

[0041] Specifically, the first transmission assembly is used to transmit the power of the first drive unit 31, and the second transmission assembly is used to transmit the power of the second drive unit 32. The first transmission assembly includes a first linear motion member 410 and a first transmission rod 411, and the second transmission assembly includes a second linear motion member 420 and a second transmission rod 421.

[0042] Exemplarily, the first transmission rod 411 and the second transmission rod 421 are connected to the corresponding nut seat 404 via spherical bearings. The second rotating part 52 and the third rotating part 53 are formed as a cross-axis assembly to provide corresponding degrees of freedom of movement.

[0043] The robot joint 102 includes a first motion branch, a second motion branch and a third motion branch. The first motion branch includes a first drive unit 31, a first linear motion member 410, a first transmission rod 411 and a second rotating part 52. The second motion branch includes a second drive unit 32, a second linear motion member 420, a second transmission rod 421 and a third rotating part 53. The third motion branch includes a third drive unit 33, a support transmission shaft 452, a fourth rotating part 54 and a support output shaft 451. The first motion branch and the second motion branch are symmetrically arranged in parallel. The third motion branch is independent of the first motion branch and the second motion branch. The third motion branch is arranged below the first motion branch and the second motion branch. The third motion branch is arranged in the middle of the first motion branch and the second motion branch.

[0044] The robot joint of the above preferred embodiment can realize active pitch motion, active roll motion and active internal and external rotation motion based on the first motion branch and the second motion branch with two degrees of freedom parallel symmetry, combined with the third motion branch arranged in the middle below the first motion branch and the second motion branch and moving independently, and the robot joint has good flexibility; by placing the driving part at the far end of the robot joint, the center of gravity of the robot joint is moved backward, thereby reducing the motion inertia of the robot joint; in addition, based on the structural arrangement and the connecting rod transmission form, the structure of the robot joint is compact, rigid and has high load.

[0045] A specific embodiment of the present invention is also used to provide a robotic arm, which includes a palm and fingers connected to the palm through base joints, and the base joints can be formed into any three-degree-of-freedom robot joint described above, wherein the robotic arm includes several fingers, and at least one of the fingers includes the three-degree-of-freedom robot joint described above.

[0046] When the motion and power of the third drive unit are transmitted to the support output shaft via the support transmission shaft and the fourth rotating portion, the robotic finger includes a first knuckle connected to the base joint and a second knuckle rotatably connected to the first knuckle. The first knuckle includes a third transmission assembly connected to the support output shaft. The third transmission assembly includes a third linear motion member and a third transmission rod. The third linear motion member converts the third rotational motion into linear motion and transmits it via the third transmission rod, thereby causing the second knuckle to flex and extend. In other words, the third drive unit is disposed at the end of the first base, remotely driving the flexion and extension of the second knuckle, which helps reduce the inertia of the robotic hand.

[0047] 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 three-degree-of-freedom robot joint, characterized in that: include: a first base extending in the axial direction; a second base rotatably connected to the first base via a first rotating portion; A driving portion providing power, comprising a first driving unit, a second driving unit, and a third driving unit, wherein the first driving unit is used to move a second rotating portion provided on the second base, and the second driving unit is used to move a third rotating portion provided on the second base, and the second base is driven to rotate around the first rotating portion to perform the first rotational motion and / or the second rotational motion by moving the second rotating portion and / or the third rotating portion; a support transmission shaft connected to the third drive unit and extending in the axial direction, the support transmission shaft being connected to the support output shaft via a fourth rotating portion, the third drive unit driving the support output shaft to rotate about the axial direction to perform a third rotational motion via the support transmission shaft and the fourth rotating portion, the rotation centers of the first rotating portion and the fourth rotating portion coinciding; The support output shaft is rotatably connected to the second base. When the second base performs the first rotational motion and / or the second rotational motion, the support output shaft moves with the second base. When the support output shaft performs the third rotational motion, the support output shaft rotates relative to the second base. The support output shaft axially penetrates the second base to transmit the third rotational motion to the front end of the second base; The robot joint includes a first motion branch, a second motion branch and a third motion branch. The first motion branch includes a first drive unit, a first linear motion member, a first transmission rod and a second rotating part. The second motion branch includes a second drive unit, a second linear motion member, a second transmission rod and a third rotating part. The first motion branch and the second motion branch are symmetrically distributed in parallel; the third motion branch includes a third drive unit, a support transmission shaft, a fourth rotating part and a support output shaft. The third motion branch is arranged below the first motion branch and the third motion branch, and the third motion branch moves independently of the first motion branch and the second motion branch.

2. The three-degree-of-freedom robot joint according to claim 1, characterized in that: When the first driving unit and the second driving unit synchronously move the second rotating part and the third rotating part in the same direction, the second base rotates around the X-axis of the first rotating part to perform a first rotational motion; when the first driving unit and the second driving unit move the second rotating part and the third rotating part in opposite directions, the second base rotates around the Y-axis of the first rotating part to perform a second rotational motion.

3. The three-degree-of-freedom robot joint according to claim 2, characterized in that: When the first driving unit and the second driving unit asynchronously move the second rotating portion and the third rotating portion in the same direction, the second base performs a composite rotational motion around the first rotating portion in which the first rotational motion and the second rotational motion are synthesized.

4. The three-degree-of-freedom robot joint according to claim 1, characterized in that: The robot joint includes a first linear motion member that converts the rotational motion of the first drive unit into linear motion, a second linear motion member that converts the rotational motion of the second drive unit into linear motion, a first transmission rod that rotatably connects the first linear motion member and the second rotating part, and a second transmission rod that rotatably connects the second linear motion member and the third rotating part.

5. The three-degree-of-freedom robot joint according to claim 1, characterized in that: The driving portion is arranged at one axial end of the first base, and the second base is arranged at the other axial end of the first base.

6. A robot, characterized in that: The invention comprises a palm and a robotic finger connected to the palm via a base joint, wherein the base joint is formed as a three-degree-of-freedom robot joint according to any one of claims 1 to 5.

7. The robot according to claim 6, characterized in that: The robotic finger includes a first knuckle connected to a base joint, and a second knuckle connected to the first knuckle, the first knuckle includes a third transmission assembly connected to an output shaft of a support, the third transmission assembly converts a third rotational motion into a linear motion to enable the second knuckle to flex and extend.

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