A robot lower limb and a robot

Abstract

The utility model discloses a kind of robot lower limbs and robot, it is related to humanoid robot technical field.Robot lower limbs include lower limb skeleton, sole and universal shaft, lower limb skeleton bottom end is connected with sole through universal shaft, and X direction and Y direction drive assembly are configured.X direction drive assembly forms the four-bar linkage drive structure around universal shaft X direction axis, Y direction drive assembly forms the four-bar linkage drive structure around universal shaft Y direction axis, realize the complete decoupling of sole rotation around two axis lines.The utility model passes through independent four-bar linkage structure design, so that each drive assembly motion parameter can be independently designed and controlled, simplify control logic and promote real-time and accuracy;While single drive assembly failure another component still can drive corresponding freedom movement, significantly enhance system reliability and motion ability retention rate.

Description

Technical Field

[0001] This utility model relates to the field of humanoid robot technology, and more specifically, to a robot lower limb and a robot. Background Technology

[0002] As an important branch of biomimetic robotics, the motion performance of the lower limb mechanism of humanoid robots directly determines the robot's walking stability, flexibility, and environmental adaptability. The ankle joint, as a key component connecting the lower leg and foot, needs to achieve two degrees of freedom: pitch (rotation around the forward / backward axis) and yaw (rotation around the left / right axis) to simulate the complex movements of the human ankle. With the expansion of humanoid robot applications, higher demands are being placed on the driving efficiency, ease of control, and fault tolerance of the ankle joint structure.

[0003] In existing technologies, ankle joint drive and connection solutions are mainly divided into two categories:

[0004] The first type is the cooperative-driven universal joint structure. As disclosed in related technologies, the ankle joint uses a universal joint to connect the lower leg and foot for rotation. Two joint modules positioned above the lower leg collaboratively drive the pitch and yaw degrees of freedom. Specifically, the output motion of the two joint modules needs to simultaneously participate in the control of two degrees of freedom, achieving ankle posture adjustment through complex motion coupling. Although this type of structure has lower torque requirements for the joint modules, because the two joint modules need to coordinate their movements in real time, the action of each module affects the output of both degrees of freedom. This results in the control system needing to handle a highly coupled kinematic model, leading to high development difficulty and long debugging cycles. Furthermore, if one joint module fails, the pitch and yaw functions of the ankle will directly fail simultaneously, significantly reducing the robot's mobility or even preventing it from walking normally, indicating poor system fault tolerance.

[0005] The second type is the independently driven multi-axis structure. To address the complexity of control in cooperative drives, existing technologies have proposed independent drive schemes, such as the technical solution disclosed in Chinese invention patent CN118810958B (authorization announcement date December 17, 2024, invention title "Lower Limb Mechanism and Humanoid Robot"). This scheme achieves decoupled control of two degrees of freedom by setting up a first drive structure and a second drive structure, which drive the lower leg component to rotate independently relative to the foot component around a first axis (pitch direction) and a second axis (yaw direction), respectively. This reduces the complexity of the control strategy and improves the system response speed. However, the drive structure in this scheme often uses crank-connecting rod direct transmission. The connection between the connecting rod and the rotating shaft requires high assembly precision. Furthermore, during the robot's dynamic walking process, the drive module and connecting rod are greatly affected by gravitational torque, leading to an increase in overall load and limiting the flexibility of ankle movement and energy utilization efficiency to some extent.

[0006] In summary, although existing technologies have made progress in decoupling ankle joint drive control, there is still room for improvement in terms of structural compactness, load optimization, and dynamic flexibility. Therefore, developing a novel ankle connection and drive structure that balances ease of control, fault tolerance, and low load characteristics has become a key technological requirement for improving the performance of humanoid robot lower limbs. Utility Model Content

[0007] The purpose of this invention is to address the technical problems in the existing humanoid robot ankle structure control system, such as high complexity, low fault tolerance, and the contradiction between load and flexibility caused by direct ankle movement, by providing a robot lower limb and robot; this invention improves the above-mentioned technical problems by adopting a reasonable arrangement of a four-bar linkage drive structure.

[0008] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0009] This utility model discloses a robot lower limb, including a universal joint, a foot, and a lower limb skeleton. The bottom end of the lower limb skeleton is connected to the foot via the universal joint. It also includes an X-axis drive assembly and a Y-axis drive assembly. The Y-axis drive assembly forms a first four-bar drive structure including the lower limb skeleton and the Y-axis of the universal joint, to drive the foot to rotate around the Y-axis of the universal joint. The X-axis drive assembly forms a second four-bar drive structure including the lower limb skeleton and the X-axis of the universal joint, to drive the foot to rotate around the X-axis of the universal joint.

[0010] Preferably, the Y-axis drive assembly includes a first drive motor and a first connecting shaft. The first drive motor is located at the other end of the lower limb skeleton relative to the foot. The first connecting shaft is connected to the foot. The axis of the first drive motor, the Y-axis of the universal joint, and the axis of the first connecting shaft are all parallel to the Y-axis. The first drive motor, the first connecting shaft, and the universal joint are connected by a first four-bar linkage drive structure.

[0011] Preferably, the X-axis drive assembly includes a second drive motor and a second connecting shaft. The second drive motor is located at the other end of the lower limb skeleton relative to the foot. The second connecting shaft is connected to the foot. The axis of the second drive motor, the X-axis of the universal joint, and the axis of the second connecting shaft are all parallel to the X-axis. The second drive motor, the first connecting shaft, and the universal joint are connected by a second four-bar linkage drive structure.

[0012] Preferably, the Y-axis drive assembly further includes a first drive arm, a first drive rod shaft, and a first drive link; one end of the first drive arm is connected to a first drive motor, and the other end of the first drive arm is connected to the first drive rod shaft, and the first drive motor drives the first drive rod shaft to rotate around the axis of the first drive motor through the first drive arm; the first drive rod shaft and the first connecting shaft are connected through the first drive link, and the axis of the first drive motor, the axis of the first drive rod, the Y-axis of the universal joint, and the axis of the first connecting shaft are all parallel to the Y-axis.

[0013] Preferably, the X-axis drive assembly further includes a second drive arm, a second drive rod shaft, and a second drive link; one end of the second drive arm is connected to a second drive motor, and the other end of the second drive arm is connected to the second drive rod shaft, and the second drive motor drives the second drive rod shaft to rotate around the axis of the second drive motor through the second drive arm; the second drive rod shaft and the second connecting shaft are connected through the second drive link, and the axis of the second drive motor, the axis of the second drive rod, the X-axis of the universal joint, and the second connecting shaft are all parallel to the X-axis.

[0014] Preferably, the first four-bar linkage drive structure and / or the second four-bar linkage drive structure are parallelogram linkage drive structures.

[0015] Preferably, the first drive rod shaft and the first drive link are connected by a radial shaft, and / or the first connecting shaft and the first drive link are connected by a radial shaft, and / or the second drive rod shaft and the second drive link are connected by a radial shaft, and / or the second connecting shaft and the second drive link are connected by a radial shaft.

[0016] Preferably, in the X direction, the distance between the universal joint and end A of the foot is L1, and the distance between the universal joint and end B of the foot is L2, where L1 ≥ L2, and the first connecting shaft is connected to end B of the foot.

[0017] Preferably, the first drive motor is positioned above the second drive motor.

[0018] The present invention relates to a robot, which includes the aforementioned robotic lower limbs.

[0019] Compared with the prior art, the technical advantages of this utility model are as follows:

[0020] 1. A robot lower limb according to this utility model includes a universal joint, a foot, and a lower limb skeleton. The bottom end of the lower limb skeleton is connected to the foot via the universal joint. It also includes an X-axis drive assembly and a Y-axis drive assembly. The Y-axis drive assembly forms a first four-bar drive structure including the lower limb skeleton and the Y-axis of the universal joint to drive the foot to rotate around the Y-axis of the universal joint. The X-axis drive assembly forms a second four-bar drive structure including the lower limb skeleton and the X-axis of the universal joint to drive the foot to rotate around the X-axis of the universal joint. By forming independent four-bar linkages with X-axis and Y-axis drive components, the rotation of the foot around the X-axis and the rotation around the Y-axis of the universal joint are completely decoupled. The motion parameters of each drive component can be designed and controlled independently, without the need for overly complex collaborative algorithms. Furthermore, the control logic can be optimized individually for a single degree of freedom, improving the real-time performance and accuracy of motion control. In addition, since the X-axis and Y-axis drive components adopt independent four-bar linkage structures, when one drive component fails, the other drive component can still drive the corresponding degree of freedom. Through structural decoupling, the scope of the fault impact is reduced to a single degree of freedom, significantly improving the robot's motion capability retention rate and enhancing the system's reliability.

[0021] 2. A robot lower limb according to this utility model, the Y-axis drive assembly further includes a first drive arm, a first drive rod shaft, and a first drive link; one end of the first drive arm is connected to a first drive motor, and the other end of the first drive arm is connected to the first drive rod shaft, the first drive motor drives the first drive rod shaft to rotate around the axis of the first drive motor through the first drive arm; the first drive rod shaft and the first connecting shaft are connected through the first drive link, the axis of the first drive motor, the axis of the first drive rod, the Y-axis of the universal joint, and the axis of the first connecting shaft are all parallel to the Y-axis; and / or the X-axis drive assembly further includes a second drive arm, a second drive rod shaft, and a second drive link; one end of the second drive arm is connected to a second drive motor, and the other end of the second drive arm is connected to the second drive rod shaft, the second drive motor drives the second drive rod shaft to rotate around the axis of the second drive motor through the second drive arm; the second drive rod shaft and the second connecting shaft are connected through the second drive link, the axis of the second drive motor, the axis of the second drive rod, the X-axis of the universal joint, and the axis of the second connecting shaft are all parallel to the X-axis. By setting the drive motor at the top of the lower limb skeleton and combining it with a four-bar linkage drive structure, power is transmitted to the foot through the drive arm, drive rod shaft and drive linkage, forming a "top drive - remote execution" force transmission path. This effectively shortens the arm of the drive motor torque and reduces the bending load on the lower limb skeleton.

[0022] 3. In a robot lower limb of this utility model, the first four-link drive structure and / or the second four-link drive structure are parallelogram link drive structures. The characteristics of the parallelogram structure ensure that the drive link always maintains translational motion during the drive process, avoiding the additional angle or displacement error that may be caused by non-parallel links, and reducing the angle accuracy error when the foot rotates around the X or Y axis.

[0023] 4. In the lower limb of a robot according to this utility model, in the X direction, the distance between the universal joint and end A of the foot is L1, and the distance between the universal joint and end B of the foot is L2, where L1≥L2. The first connecting shaft is connected to end B of the foot, so that the rotation center of the foot, i.e., the universal joint is positioned biased towards the heel side and the first connecting shaft is located at the heel. With the help of the four-bar linkage drive structure, the inertial torque when the foot rotates is reduced, and the flexibility of the robot when walking or jumping is improved.

[0024] 5. In a robot lower limb of this utility model, the first drive rod shaft and the first drive link are connected by a radial shaft, and / or the first connecting shaft and the first drive link are connected by a radial shaft, and / or the second drive rod shaft and the second drive link are connected by a radial shaft, and / or the second connecting shaft and the second drive link are connected by a radial shaft. The setting of the radial shaft reduces radial force interference in the transmission process, improves energy transmission efficiency, and further reduces the load requirements of the drive motor. Attached Figure Description

[0025] Figure 1 This is a three-dimensional view of the lower limb of a robot according to the present invention;

[0026] Figure 2 This is a side view of the lower limb of a robot according to the present invention;

[0027] Figure 3 This is a front view of the lower limb of a robot according to the present invention;

[0028] Figure 4 This is a structural diagram of the universal joint in the lower limb of a robot according to the present invention.

[0029] Reference numerals: 110, first drive motor; 111, first drive motor shaft; 120, first drive arm; 130, first drive rod shaft; 131, first drive rod shaft; 140, first drive connecting rod; 150, first connecting shaft; 151, first connecting shaft.

[0030] 210. Second drive motor; 211. Second drive motor shaft; 220. Second drive arm; 230. Second drive rod shaft; 231. Second drive rod shaft; 240. Second drive connecting rod; 250. Second connecting shaft; 251. Second connecting shaft;

[0031] 300. Universal joint; 301. X-axis; 302. Y-axis;

[0032] 400, foot; 500, lower limb skeleton. Detailed Implementation

[0033] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings and embodiments.

[0034] The structures, proportions, and sizes illustrated in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art in understanding and reading the invention. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, provided they do not affect the effectiveness or purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention. In addition, the various embodiments of the invention are not independent but can be combined.

[0035] Taking the robot's normal standing state as a reference, the coordinate axis directions are defined as follows:

[0036] X-axis: Parallel to the left and right direction of the robot;

[0037] Y-axis: parallel to the robot's forward and backward direction;

[0038] Z-axis: Parallel to the robot's vertical direction;

[0039] The origin is the geometric center of the universal joint 300, which is the connection center between the lower limb skeleton 500 and the foot 400.

[0040] One embodiment of the robot includes robotic lower limbs, such as... Figure 1-4 As shown, a robot lower limb in this embodiment includes a universal joint 300, a foot 400, and a lower limb skeleton 500. The bottom end of the lower limb skeleton 500 is connected to the foot 400 through the universal joint 300. It also includes an X-axis drive assembly and a Y-axis drive assembly.

[0041] The Y-axis drive assembly of this embodiment includes a first drive motor 110 and a first connecting shaft 150. The first drive motor 110 is disposed at the other end of the lower limb skeleton 500 relative to the foot 400. The first connecting shaft 150 is connected to the foot 400. The first drive motor axis 111, the Y-axis axis 302 of the universal joint 300 and the first connecting shaft axis 151 are all parallel to the Y-axis. The first drive motor 110, the first connecting shaft 150 and the universal joint 300 are connected by a first four-bar linkage drive structure.

[0042] Specifically, in this embodiment, the Y-axis drive assembly further includes a first drive arm 120, a first drive rod shaft 130, and a first drive connecting rod 140; one end of the first drive arm 120 is connected to a first drive motor 110, and the other end of the first drive arm 120 is connected to the first drive rod shaft 130. The first drive motor 110 drives the first drive rod shaft 130 to rotate around the first drive motor axis 111 through the first drive arm 120; the first drive rod shaft 130 and the first connecting shaft 150 are connected through the first drive connecting rod 140, and the first drive motor axis 111, the first drive rod axis 131, the Y-axis 302 of the universal joint 300, and the first connecting shaft 151 are all parallel to the Y-axis.

[0043] The X-axis drive assembly of this embodiment includes a second drive motor 210 and a second connecting shaft 250. The second drive motor 210 is disposed at the other end of the lower limb skeleton 500 relative to the foot 400. The second connecting shaft 250 is connected to the foot 400. The axis 211 of the second drive motor, the X-axis 301 of the universal joint 300, and the second connecting shaft 251 are all parallel to the X-axis. The second drive motor 210, the first connecting shaft 150, and the universal joint 300 are connected by a second four-bar linkage drive structure.

[0044] Specifically, the X-axis drive assembly also includes a second drive arm 220, a second drive rod shaft 230, and a second drive link 240; one end of the second drive arm 220 is connected to a second drive motor 210, and the other end of the second drive arm 220 is connected to the second drive rod shaft 230. The second drive motor 210 drives the second drive rod shaft 230 to rotate around the second drive motor axis 211 through the second drive arm 220; the second drive rod shaft 230 and the second connecting shaft 250 are connected through the second drive link 240. The second drive motor axis 211, the second drive rod axis 231, the X-axis 301 of the universal joint 300, and the second connecting shaft 251 are all parallel to the X-axis.

[0045] By forming independent four-bar linkages with the aforementioned X-axis and Y-axis drive components, the rotation of the foot around the X-axis 301 and the rotation around the Y-axis 302 of the universal joint are completely decoupled. The motion parameters (such as speed and torque) of each drive component can be designed and controlled independently without the need for overly complex collaborative algorithms. Furthermore, the control logic can be optimized individually for a single degree of freedom, improving the real-time performance and accuracy of motion control. In addition, since the X-axis and Y-axis drive components adopt independent four-bar linkage structures, when one drive component fails, the other drive component can still drive the motion of the corresponding degree of freedom. Through structural decoupling, the scope of the fault impact is reduced to a single degree of freedom, improving the robot's motion capability retention rate and significantly enhancing the reliability of the system.

[0046] In this embodiment, the first four-bar linkage drive structure and / or the second four-bar linkage drive structure are parallelogram linkage drive structures. The characteristics of the parallelogram structure ensure that the drive linkage always maintains translational motion during the drive process, avoiding the additional angle or displacement error that may be generated by non-parallel linkages, and reducing the angle accuracy error when the foot rotates around the X-axis or Y-axis.

[0047] Furthermore, the first drive shaft 130 and the first drive link 140 are connected by a radial shaft, and / or the first connecting shaft 150 and the first drive link 140 are connected by a radial shaft, and / or the second drive shaft 230 and the second drive link 240 are connected by a radial shaft, and / or the second connecting shaft 250 and the second drive link 240 are connected by a radial shaft. This arrangement positions the foot's rotation center, i.e., the universal joint, towards the heel side, with the first connecting shaft located at the heel. Combined with the four-bar linkage drive structure, this reduces the inertial torque during foot rotation, improving the robot's agility during walking or jumping.

[0048] In addition, in this embodiment, the first drive motor 110 is positioned above the second drive motor 210, and the two drive components are arranged in layers in space to avoid motion interference and further ensure the smoothness of transmission.

[0049] In this embodiment, the first drive rod shaft 130 and the first drive connecting rod 140 are connected by a radial shaft, and / or the first connecting shaft 150 and the first drive connecting rod 140 are connected by a radial shaft, and / or the second drive rod shaft 230 and the second drive connecting rod 240 are connected by a radial shaft, and / or the second connecting shaft 250 and the second drive connecting rod 240 are connected by a radial shaft. The radial shaft reduces radial force interference during transmission, improves energy transfer efficiency, and further reduces the load requirements of the drive motor.

[0050] In this embodiment, in the X direction, the distance between the universal joint 300 and the foot end 400A is L1, and the distance between the universal joint 300 and the foot end 400B is L2, where L1 ≥ L2. The first connecting shaft 150 is connected to the foot end 400B. In this embodiment, the foot end 400A is the toe part, and the foot end 400B is the heel part. The above arrangement makes the rotation center of the foot, i.e., the universal joint, biased towards the heel side, and the first connecting shaft is located at the heel. With the four-bar linkage drive structure, the inertial torque when the foot rotates is reduced, and the flexibility of the robot when walking or jumping is improved.

[0051] The present invention has been described in detail above with reference to specific exemplary embodiments. However, it should be understood that various modifications and variations can be made without departing from the scope of the present invention as defined by the appended claims. The detailed description and drawings should be considered illustrative only and not restrictive, and any such modifications and variations shall fall within the scope of the present invention described herein. Furthermore, the background art is intended to illustrate the current state of research and development and significance of the technology, and is not intended to limit the scope of application of the present invention or this application.

[0052] More specifically, although exemplary embodiments of the present invention have been described herein, the present invention is not limited to these embodiments, but includes any and all embodiments modified, omitted, such as combinations between various embodiments, adaptive changes, and / or substitutions, as would be apparent to those skilled in the art from the foregoing detailed description. The limitations in the claims are to be interpreted broadly as used in the language of the claims and are not limited to the examples described in the foregoing detailed description or during the implementation of this application, which should be considered non-exclusive. Any step listed in any method or process claim may be performed in any order and is not limited to the order set forth in the claims. Therefore, the scope of the present invention should be determined solely by the appended claims and their legal equivalents, and not by the description and examples given above.

Claims

1. A robotic lower limb, characterized in that, The device includes a universal joint (300), a foot (400), and a lower limb skeleton (500), the bottom end of which is connected to the foot (400) via the universal joint (300); it also includes an X-axis drive assembly and a Y-axis drive assembly, the Y-axis drive assembly forming a first four-bar drive structure including the lower limb skeleton (500) and the Y-axis (302) of the universal joint (300) to drive the foot (400) to rotate around the Y-axis (302) of the universal joint (300); the X-axis drive assembly forming a second four-bar drive structure including the lower limb skeleton (500) and the X-axis (301) of the universal joint (300) to drive the foot (400) to rotate around the X-axis (301) of the universal joint (300).

2. The robotic lower limb according to claim 1, characterized in that, The Y-axis drive assembly includes a first drive motor (110) and a first connecting shaft (150). The first drive motor (110) is located at the other end of the lower limb skeleton (500) relative to the foot (400). The first connecting shaft (150) is connected to the foot (400). The axis of the first drive motor (111), the Y-axis of the universal joint (300) and the axis of the first connecting shaft (151) are all parallel to the Y-axis. The first drive motor (110), the first connecting shaft (150) and the universal joint (300) are connected by a first four-bar linkage drive structure.

3. A robotic lower limb according to claim 2, characterized in that, The X-axis drive assembly includes a second drive motor (210) and a second connecting shaft (250). The second drive motor (210) is located at the other end of the lower limb skeleton (500) relative to the foot (400). The second connecting shaft (250) is connected to the foot (400). The axis of the second drive motor (211), the X-axis of the universal joint (300), and the axis of the second connecting shaft (251) are all parallel to the X-axis. The second drive motor (210), the first connecting shaft (150), and the universal joint (300) are connected by a second four-bar linkage drive structure.

4. A robotic lower limb according to claim 2, characterized in that, The Y-axis drive assembly also includes a first drive arm (120), a first drive rod shaft (130), and a first drive link (140); one end of the first drive arm (120) is connected to a first drive motor (110), and the other end of the first drive arm (120) is connected to the first drive rod shaft (130). The first drive motor (110) drives the first drive rod shaft (130) to rotate around the axis (111) of the first drive motor through the first drive arm (120); the first drive rod shaft (130) and the first connecting shaft (150) are connected through the first drive link (140). The axis (111) of the first drive motor, the axis (131) of the first drive rod, the Y-axis (302) of the universal joint (300), and the axis (151) of the first connecting shaft (151) are all parallel to the Y-axis.

5. A robotic lower limb according to claim 3, characterized in that, The X-axis drive assembly also includes a second drive arm (220), a second drive rod shaft (230), and a second drive link (240); one end of the second drive arm (220) is connected to a second drive motor (210), and the other end of the second drive arm (220) is connected to the second drive rod shaft (230). The second drive motor (210) drives the second drive rod shaft (230) to rotate around the axis (211) of the second drive motor through the second drive arm (220); the second drive rod shaft (230) and the second connecting shaft (250) are connected through the second drive link (240). The axis (211) of the second drive motor, the axis (231) of the second drive rod, the X-axis (301) of the universal joint (300), and the second connecting shaft (251) are all parallel to the X-axis.

6. A robotic lower limb according to claim 1, characterized in that, The first four-bar linkage drive structure and / or the second four-bar linkage drive structure are parallelogram linkage drive structures.

7. A robotic lower limb according to claim 4 or 5, characterized in that, The first drive rod shaft (130) and the first drive link (140) are connected by a radial shaft, and / or the first connecting shaft (150) and the first drive link (140) are connected by a radial shaft, and / or the second drive rod shaft (230) and the second drive link (240) are connected by a radial shaft, and / or the second connecting shaft (250) and the second drive link (240) are connected by a radial shaft.

8. A robotic lower limb according to claim 1, characterized in that, In the X direction, the distance between the universal joint (300) and end A of the foot (400) is L1, and the distance between the universal joint (300) and end B of the foot (400) is L2, where L1≥L2, and the first connecting shaft (150) is connected to end B of the foot (400).

9. A robotic lower limb according to claim 3, characterized in that, The first drive motor (110) is positioned above the second drive motor (210).

10. A robot, characterized in that, It includes the robotic lower limb as described in any one of claims 1-9.

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