A foot structure for a humanoid robot and a humanoid robot

Abstract

The utility model provides a kind of foot structure and humanoid robot for humanoid robot, including sole, heel, direct drive motor and flange bearing.Sole is contacted with ground, realizes left and right rotation;Heel is connected with calf, realizes front and back rotation.Direct drive motor is installed in sole front end, is connected heel by motor rotor, controls left and right rotation.Flange bearing is installed in heel upper end, is connected with calf, controls front and back rotation.Single-double ankle conversion mechanism is fixed or releases rotation by screw through sole side surface through-hole and heel screw hole.When sole and heel are loosened, motor drives sole to rotate relative to heel, realizes double ankle function;Screw fixation is single-ankle state.This design not only simplifies the complexity of traditional double-ankle design, reduces production cost and time consumption, but also improves the adaptability and flexibility of foot, so that robot can better adapt to complex terrain and diversified environment.

Description

Technical Field

[0001] This utility model relates to robotics technology, and in particular to a foot structure for a humanoid robot and a humanoid robot. Background Technology

[0002] With the continuous advancement of human science and technology and the rapid growth of intelligent demands, research on humanoid robots has gradually become a focus of attention for the global academic and industrial communities. As an important branch of robotics, humanoid robots can not only mimic human movements and forms but also possess the potential to adapt to complex environments, showing great application prospects in fields such as service, healthcare, and rescue. However, the design of humanoid robot feet often involves various physical characteristics, mechanical structures, and control algorithms to achieve higher levels of flexibility, stability, and adaptability. Especially in real and complex environments, humanoid robots must cope with different terrains, directional changes, and other factors, placing even more stringent requirements on their foot structures.

[0003] Traditional humanoid robot foot designs often employ a single-ankle structure, meaning each foot has only one rotational joint, typically rotating in the forward / backward direction, to achieve basic gait control and terrain adaptability. This design is relatively simple in robot control and manufacturing due to its fewer structures and lower control system complexity. Furthermore, the single rotational degree of freedom facilitates smooth control, providing a degree of stability, particularly suitable for walking on flat surfaces. However, the single-ankle design also faces limitations. With only one degree of freedom, it is less adaptable to uneven or irregular terrain, unable to make subtle posture adjustments or respond to sudden directional changes. Its gait flexibility is relatively low. Therefore, in practical applications, single-ankle humanoid robots are suitable for scenarios requiring high ground flatness or industrial applications demanding greater stability, but are clearly insufficient for the diversity and complexity of human environments.

[0004] In contrast, the bi-ankle design provides two rotational degrees of freedom for each foot, typically with joints positioned in both the forward / backward and left / right directions, better mimicking the multidimensional movement patterns of the human ankle. This structure offers greater mobility, especially on complex terrain, uneven surfaces such as slopes, or inclines. The bi-ankle design allows for more flexible adjustments to the robot's posture to maintain balance and stability. Thanks to the two independent rotational degrees of freedom, bi-ankle robots can achieve diverse gait patterns, such as walking on slopes, lateral tilting, and agile turning in confined spaces, greatly improving the robot's ability to adapt to diverse environments.

[0005] However, bi-ankle structures also present significant challenges in design and control. Existing bi-ankle designs mostly employ two links for primary transmission control of the ankle's left and right rotation. In this method, the movement of the links is no longer planar but three-dimensional, requiring multiple bearings or articulated ball bearings. This complex structure continuously increases manufacturing costs. Furthermore, the dual-link drive design also increases the complexity of algorithmic solutions, significantly raising the difficulty of motion control. On the other hand, while bi-ankles offer better stability in humanoid robot debugging, control based on reinforcement learning or MPC is relatively difficult. Many teams need to start with single-ankle debugging and later advance to bi-ankle. In this case, most single-ankle and bi-ankle structures are designed and manufactured separately, resulting in time-consuming and costly processes.

[0006] The most common type of bi-ankle foot design is a double-link design. A cross-shaped pivot is incorporated into the foot, allowing for rotation in both forward / backward and left / right directions. Two drive motors are mounted on the lower legs of the humanoid robot, connected to the cross-shaped pivot via two links. When one motor rotates while the other does not, the foot rotates left / right, achieving a side roll; when both motors rotate synchronously, the foot rotates forward / backward, achieving a forward / backward flip; when both motors rotate simultaneously but asynchronously, the foot rotates in both left / right and forward / backward directions, achieving omnidirectional rotation. Its disadvantages include: 1. The double-link drive is a single-stage transmission, resulting in lower transmission accuracy and stability compared to direct drive. 2. The structure is complex, requiring difficult-to-design components and incurring high costs. 3. Motion control calculations are extremely complex, and the ball bearings used in the links have infinite solutions during movement, leading to low motion stability.

[0007] Another type of humanoid robot foot design uses a single-ankle design, meaning it only has rotational freedom in the forward and backward direction. This design uses a single-link, single-stage transmission drive, with a motor mounted on the lower leg. The link and foot form a parallelogram, allowing the motor to drive the forward and backward rotation of the foot. Its disadvantages are: 1. This design only allows for forward and backward rotation, preventing lateral rotation. When the humanoid robot needs to maintain stability, it can only adjust via the thigh motor, unable to maintain stability through lateral foot rotation. 2. When the humanoid robot moves laterally, the foot cannot remain parallel to the ground, leading to unsolvable or extremely unstable movement.

[0008] Existing humanoid robot foot designs are mainly divided into two types: single-ankle and double-ankle. These two designs are independent of each other. The mainstream double-ankle dual-parallel linkage drive also has problems such as instability and complex structure.

[0009] It should be noted that the information disclosed in the background section above is only for understanding the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content

[0010] The main purpose of this invention is to overcome the defects in the above-mentioned background technology, and to provide a foot structure for humanoid robots and a humanoid robot. This invention provides a humanoid robot foot structure that is compact, easy to control, and can flexibly switch between single-ankle and double-ankle movement modes, so as to improve the robot's adaptability to complex terrain and reduce its research and development and manufacturing costs.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] A foot structure for a humanoid robot, comprising:

[0013] The ball of the foot is used to contact the ground and achieve rotational freedom in the left and right directions;

[0014] The heel is used to connect to the robot's lower leg and enable rotational freedom in the forward and backward directions;

[0015] A direct-drive motor is installed at the front of the foot, with the motor housing fixedly connected to the foot. The motor rotor extends out of the foot and connects to the heel to achieve the left and right rotational freedom of the foot.

[0016] A flange bearing is installed on the upper part of the heel and connected to the robot's lower leg to enable rotational freedom in the front-back direction of the foot;

[0017] The single / double ankle switching mechanism includes through holes on the side of the foot and threaded holes on the heel, where screws are screwed in or loosened to fix or release the relative rotation between the foot and heel; when the foot and heel are loosened, the foot can rotate relative to the heel under the drive of the motor, which is a double ankle state; when it is tightened, the foot cannot rotate relative to the heel, which is a single ankle state.

[0018] Furthermore, the through hole on the side of the foot is set in the circular groove on the side of the foot, the heel is fixed to the motor rotor by a circular boss, and the threaded hole is set on the side of the circular boss.

[0019] Furthermore, it also includes: insoles, installed at the bottom of the foot, to provide cushioning and anti-slip properties.

[0020] Furthermore, it also includes a heavy-duty omnidirectional ball, positioned between the ball of the foot and the heel, to assist rotation and provide support.

[0021] Furthermore, the heavy-duty omnidirectional ball comprises at least two first omnidirectional balls and one second omnidirectional ball, wherein:

[0022] The first omnidirectional ball is installed at a 45° angle in the groove of the semi-circular boss on the foot to provide lateral support;

[0023] The second omnidirectional ball is vertically mounted in the groove of the square boss on the foot to provide vertical support;

[0024] The ball bearings of the heavy-duty omnidirectional ball face upwards to ensure smooth rotation of the foot in the left and right directions and reduce friction and wear during rotation.

[0025] Furthermore, there are two flange bearings, which are installed opposite each other in the circular groove through hole at the upper end of the heel, with a slight gap between them to prevent misalignment in the axial direction.

[0026] Furthermore, the insole is made of silicone material and has a groove at the bottom, which is fixed to the foot by screwing in screws.

[0027] Furthermore, the sole and heel are made of materials with high specific strength and high specific stiffness to increase bending resistance and reduce fatigue issues.

[0028] Furthermore, the foot rotation limit is designed to be -45° to 45°, which is achieved by the square protrusions on both sides of the rear end of the heel contacting the heavy-duty omnidirectional ball.

[0029] A humanoid robot having the aforementioned humanoid robot foot structure.

[0030] This utility model has the following beneficial effects:

[0031] This invention provides a foot structure for humanoid robots, which achieves significant technical advantages through an innovative single / double ankle switching method. The foot structure employs a direct-drive motor design, integrating the motor controlling left and right rotation into the foot to achieve double ankle functionality while ensuring drive stability and significantly reducing the complexity of the motion control algorithm. The single / double ankle switching mechanism, using through holes on the side of the foot and threaded holes on the heel, allows for easy switching between single and double ankle states simply by tightening or loosening screws. In the double ankle state, the foot can rotate relative to the heel, providing additional left and right rotational freedom. In the single ankle state, the foot and heel are fixed as a rigid body, and the motor rotor can no longer drive the foot to rotate. This design not only simplifies the complexity of traditional double ankle designs, reducing production costs and time, but also improves the adaptability and flexibility of the foot, enabling the robot to better adapt to complex terrains and diverse environments. Furthermore, the modular connection, lightweight design, and stable heel support structure of the foot structure significantly improve the overall performance and durability, giving this invention a clear advantage in enhancing the walking flexibility and balance of humanoid robots.

[0032] Compared with the prior art, the main advantages of the embodiments of this utility model are:

[0033] 1. The foot's dual-ankle design is achieved by using a direct-drive motor, which greatly simplifies the complexity of the motion control algorithm and makes the foot's operation more stable and precise.

[0034] 2. The rotating joints in the front-to-back and left-to-right directions have been split and integrated into a single design. Unlike the cross-axis design commonly used in existing double ankle designs, this design results in more stable rotation and less gap and play.

[0035] 3. A simple single and double ankle switching method was designed, allowing the foot to switch freely between single and double ankles.

[0036] 4. A stable heel support structure was designed to avoid the cantilever beam problem in the foot connection part and enhance the bending resistance.

[0037] 5. It adopts a relatively lightweight integrated design, integrating devices such as single and double ankle switching devices and left and right rotation limiting devices into the ball of the foot and heel, avoiding too many structural parts.

[0038] Other beneficial effects of the embodiments of this utility model will be further described below. Attached Figure Description

[0039] Figure 1 This is an overall structural diagram of the foot design according to an embodiment of the present utility model.

[0040] Figure 2 This is an exploded view of the overall embodiment of this utility model.

[0041] Figure 3 This is a diagram of the integrated structure for single and double ankle conversion and rotation limiting according to an embodiment of the present invention.

[0042] Figure 4 This is a diagram of the mechanical limiting structure for double ankle rotation according to an embodiment of the present invention. Detailed Implementation

[0043] The embodiments of this utility model are described in detail below. It should be emphasized that the following description is merely exemplary and not intended to limit the scope and application of this utility model.

[0044] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component. Furthermore, a connection can be used for fixing, coupling, or communication.

[0045] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this utility model 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 should not be construed as limitations on this utility model.

[0046] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0047] See Figures 1 to 4 In some embodiments, a foot structure for a humanoid robot mainly includes a foot 1, a heel 2, a direct drive motor 3, a flange bearing 5, and a single / double ankle switching mechanism.

[0048] The foot 1 is designed to contact the ground and achieve rotational freedom in the left and right directions. The heel 2 is used to connect to the robot's lower leg and achieve rotational freedom in the front and back directions.

[0049] A direct-drive motor 3 is mounted on the front end of the foot 1, and the motor housing is fixedly connected to the foot 1 with screws. The motor rotor extends out of the foot 1 and connects to the heel 2, thereby realizing the left-right rotational freedom of the foot and enhancing the accuracy and stability of the transmission.

[0050] The single / double ankle conversion mechanism includes a through hole 6 on the side of the foot 1 and a threaded hole 7 on the heel 2. The relative rotation between the foot 1 and the heel 2 is fixed or released by screwing in or loosening the screws. When the foot 1 and the heel 2 are loosened, the foot 1 can rotate relative to the heel 2 under the drive of the direct drive motor 3 (through the motor housing), and is in a double ankle state. When it is tightened, the foot 1 cannot rotate relative to the heel 2 and is in a single ankle state.

[0051] Flange bearing 5 is installed on the upper end of heel 2 and connected to the robot's lower leg (not shown), enabling rotational freedom in the front-to-back direction of the foot. To ensure stability, two flange bearings 5 ​​are installed opposite each other in the circular groove through-hole on the upper end of heel 2, with a slight gap between them to prevent axial misalignment.

[0052] Preferably, a heavy-duty omnidirectional ball 4 is provided between the foot 1 and the heel 2 to ensure smooth rotation and provide stable support. The heavy-duty omnidirectional ball 4 includes at least two first omnidirectional balls (SP-8 omnidirectional balls can be used) and one second omnidirectional ball (SP-12 omnidirectional ball can be used). The first omnidirectional balls are installed at a 45° angle in the groove of the semi-circular boss of the foot 1 to provide lateral support; the second omnidirectional ball is installed vertically in the groove of the square boss of the foot 1 to provide vertical support. The ball bearings of all the heavy-duty omnidirectional balls 4 face upwards to ensure smooth rotation of the foot 1 in the left and right directions and to reduce friction and wear during rotation. The omnidirectional ball base can be fixed to the groove of the foot. The heavy-duty omnidirectional ball can be selected to accommodate changes in the contact surface angle, and the omnidirectional ball is selected considering impact loads.

[0053] In addition, the foot structure includes an insole 8, made of silicone material (such as 70A silicone material). The groove on the bottom of the insole 8 is fixed to the foot 1 by screws, providing cushioning and anti-slip function.

[0054] Both the ball of the foot 1 and the heel 2 are made of materials with high specific strength and high specific stiffness to increase bending resistance and reduce fatigue. Specific materials such as aluminum alloy, titanium alloy, or carbon fiber composites can be used to enhance bending and fatigue resistance. The rotation limit of the ball of the foot 1 is designed to be -45° to 45°, achieved by the contact between the square protrusions 9 on both sides of the rear end of the heel 2 and the heavy-duty omnidirectional ball 4, ensuring the precision and control of foot movement.

[0055] The humanoid robot's foot structure, through its unique design, not only provides excellent freedom of movement and stability, but also simplifies the manufacturing and maintenance process.

[0056] This utility model embodiment also provides a humanoid robot having the foot structure of any of the foregoing embodiments.

[0057] The following further describes specific embodiments of this utility model.

[0058] Figure 1 The overall structure of the foot design for a humanoid robot is shown. The main design features of the foot structure are:

[0059] The foot design has two degrees of freedom: rotation in the forward and backward directions and rotation in the left and right directions. The rotation in the left and right directions is achieved by direct drive of the motor, and there is a limit design for this left and right rotation, with a movement angle of -45° to 45°.

[0060] The key components of this foot design are the design of the ball of the foot 1 and the heel 2. The two are independent and can achieve relative and synchronous movement to enable the overall forward and backward rotation of the foot and the individual left and right rotation of the ball of the foot 1. The connection between the two is stable and reliable. High specific strength and high specific stiffness materials are selected, and a support design is adopted to increase its bending resistance and reduce its overall fatigue.

[0061] This foot design features a close integration, with the switching design between single and double ankles and the limiting design for left and right rotation integrated into the heel 2 and the foot 1, reducing the number of parts and achieving lightweight and high integration.

[0062] To facilitate ankle movement, the foot was designed using a modular design principle, dividing the entire structure into two parts: the ball of the foot (1) and the heel (2). Figure 1 The diagram shows the overall structure of the designed foot. The heel 2 is a modular component that connects to the lower leg of the humanoid robot, and the foot 1 is a fixed connection component that connects to the direct drive motor 3. Figure 1 The two arrows in the diagram indicate the rotation directions of the foot (1) and heel (2).

[0063] Figure 2The diagram shows an exploded view of the entire foot, including a direct drive motor 3, insole 8, foot arch 1, heel 2, heavy-duty omnidirectional ball joint 4, and flange bearing 5. The direct drive motor 3 is mounted on the front end of the foot arch 1 and is fixed to its housing by six screws, allowing the rotor of the motor 3 to extend through a hole in the foot arch 1. The heavy-duty omnidirectional ball joint 4 comes in two types: two SP-8 and one SP-12. The SP-8 is installed at a 45° angle in the groove of the semi-circular boss of the foot arch 1, while the SP-12 is installed vertically in the groove of the square boss of the foot arch 1, with both ball joints facing upwards. The heel 2 is connected to the rotor of the direct drive motor 3 through four M3 light holes on the front circular boss. Here, the motor is reversed, and relative rotation is achieved through different connections between the stator and the rotor. The outer shell (stator) is fixed to the foot 1, while the output shaft (rotor) is connected to the heel 2. By controlling the motor, the foot 1 can be driven to rotate relative to the heel 2. The structural component fixed to the motor shell, i.e., the foot 1, rotates relative to the structural component fixed to the motor rotor, thereby realizing the rotational freedom of the foot 1 in the left and right directions. (In this design, the motor rotor and the heel can also be decoupled through a separable coupling or similar structure. The motor cable can be a torsion-resistant flexible cable.) The arc-shaped structure below the heel 2 is tangentially connected to three heavy-duty universal balls 4. When the foot 1 rotates, the three heavy-duty universal balls 4 roll into contact with the arc surface of the heel 2, ensuring smooth rotation and providing support, avoiding the bending of the foot 1 caused by the cantilever beam phenomenon. Two flange bearings 5 ​​are installed opposite each other in the circular groove through-hole at the upper end of the heel 2, with a 0.2mm gap between them to prevent contact between the two flange bearings 5 ​​and thus prevent axial play, ensuring stability. This gap can be used to adjust axial preload, and with high-precision machining, it can reduce radial runout. The flange bearing 5 is the connecting pivot between the foot and the lower leg of the humanoid robot, allowing the foot to rotate freely in the forward and backward directions. The insole 8 is installed at the lower end of the foot 1, using 70A silicone as the 3D printing material, which has anti-slip and cushioning characteristics, and is connected to the bottom of the foot 1 by screwing in several screws through the grooves on the bottom.

[0064] Figure 3 The diagram shows the integrated structure for single / double ankle switching and rotation limiting. To achieve integrated single / double ankle functionality and facilitate easy switching, two 3mm diameter through holes 6 and a 6mm diameter circular groove are provided on the side of the foot 1. Additionally, on the side of the circular boss that fixes the heel 2 to the motor rotor, two threaded holes 7 are provided at positions corresponding to the through holes 6. When the foot device needs to be set to a single ankle state, simply screw in two M3 screws on the side to fix the foot 1 and heel 2 together. At this point, the foot 1 and heel 2 are rigidly connected, and the motor can no longer drive the foot 1 to rotate, thus achieving the single ankle state. When these two screws are not screwed in, the foot 1 rotates under motor control, achieving the double ankle state.

[0065] In the motion control of humanoid robots, it is necessary to define the range of motion of each joint. In reality, it is also necessary to fix the range of motion of the joints through mechanical limits. To achieve a high degree of integration, two square protrusions 9 are set on both sides of the rear end of the heel 2, and the rotation angle is set to ±45°. Figure 4 The diagram shows the mechanical limiting structure for ankle rotation. When the rotation reaches ±45°, the provided boss will contact the SP-12 heavy-duty omnidirectional ball joint 4, preventing further rotation.

[0066] Compared to traditional robot foot designs, this invention's humanoid robot foot structure, through a direct-drive motor design, achieves single / double ankle switching functionality, providing a stable structure, simplified control algorithm, and easy transition between single and double ankle states. This design, by directly integrating the motor into the foot, not only improves drive stability and transmission accuracy but also significantly reduces the complexity of the motion control algorithm. Compared to traditional dual-parallel linkage drives, this invention's direct-drive motor method is more stable and reliable, reduces the number of overall components, and optimizes the spatial layout of the humanoid robot's lower leg structure.

[0067] This invention's single / double ankle switching mechanism allows for easy conversion between single and double ankle modes using screws via through holes and threaded holes on the side of the foot and heel. In double ankle mode, the motor drives the foot to rotate relative to the heel, providing additional lateral rotational freedom and enhancing the robot's adaptability and flexibility in complex terrain. In single ankle mode, the foot and heel are fixed together as a rigid body, simplifying the foot structure and improving gait stability. This simplified conversion method reduces production costs and time, eliminating the need for repetitive design and processing.

[0068] This invention features a foot structure with a decomposed design of rotating joints in both the forward / backward and left / right directions, providing stable rotation and limiting, thus making foot movements more precise. The heel support structure design avoids the cantilever beam problem of the foot joint, enhancing the structure's bending resistance. The lightweight integrated design integrates the single / double ankle conversion device and the left / right rotation limiting device into the foot and heel, avoiding excessive structural components and further improving the foot's performance and durability.

[0069] In summary, the foot structure design of this utility model, with its innovative single / double ankle switching method, stable direct-drive motor technology, optimized spatial layout, and lightweight structure, provides an effective solution for improving the adaptability and flexibility of humanoid robots. At the same time, it simplifies the design and manufacturing process, reduces costs, and provides significant advantages for industrial applications.

[0070] The above description, in conjunction with specific / preferred embodiments, provides a further detailed explanation of the present invention and should not be construed as limiting the specific implementation of the present invention to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the protection scope of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the described specific features, structures, materials, or characteristics can be combined in a suitable manner in any one or more embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples. Although embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the scope of protection of the patent application.

Claims

1. A foot structure for a humanoid robot, characterized in that, include: The ball of the foot is used to contact the ground and achieve rotational freedom in the left and right directions; The heel is used to connect to the robot's lower leg and enable rotational freedom in the forward and backward directions; A direct-drive motor is installed at the front of the foot, with the motor housing fixedly connected to the foot. The motor rotor extends out of the foot and connects to the heel to achieve the left and right rotational freedom of the foot. A flange bearing is installed on the upper part of the heel and connected to the robot's lower leg to enable rotational freedom in the front-back direction of the foot; The single / double ankle switching mechanism includes through holes on the side of the foot and threaded holes on the heel, where screws are screwed in or loosened to fix or release the relative rotation between the foot and heel; when the foot and heel are loosened, the foot can rotate relative to the heel under the drive of the motor, which is a double ankle state; when it is tightened, the foot cannot rotate relative to the heel, which is a single ankle state.

2. The foot structure for a humanoid robot according to claim 1, characterized in that, The through hole on the side of the foot is set in the circular groove on the side of the foot, and the heel is fixed to the motor rotor by a circular boss. The threaded hole is set on the side of the circular boss.

3. The foot structure for a humanoid robot according to claim 1 or 2, characterized in that, Also includes: Insoles, installed at the bottom of the foot, provide cushioning and anti-slip properties.

4. The foot structure for a humanoid robot according to claim 1 or 2, characterized in that, Also includes: A heavy-duty swivel ball is positioned between the ball of the foot and the heel to assist rotation and provide support.

5. The foot structure for a humanoid robot according to claim 4, characterized in that, The heavy-duty omnidirectional ball includes at least two first omnidirectional balls and one second omnidirectional ball, wherein: The first omnidirectional ball is installed at a 45° angle in the groove of the semi-circular boss on the foot to provide lateral support; The second omnidirectional ball is vertically mounted in the groove of the square boss on the foot to provide vertical support; The ball bearings of the heavy-duty omnidirectional ball face upwards to ensure smooth rotation of the foot in the left and right directions and reduce friction and wear during rotation.

6. The foot structure for a humanoid robot according to claim 1 or 2, characterized in that, The flange bearing consists of two parts, which are installed opposite each other in the circular groove through hole at the upper end of the heel, with a slight gap between them to prevent misalignment in the axial direction.

7. The foot structure for a humanoid robot according to claim 1 or 2, characterized in that, The single / double ankle switching mechanism secures or releases rotation between the foot and heel by screwing in or loosening an M3 screw in a through-hole on the side of the foot.

8. The foot structure for a humanoid robot according to claim 3, characterized in that, The insole is made of silicone material and has a groove at the bottom, which is screwed into the foot for secure connection.

9. The foot structure for a humanoid robot according to claim 4, characterized in that, The foot's rotation limit is designed to be -45° to 45°, which is achieved by the square protrusions on both sides of the rear end of the heel contacting the heavy-duty omnidirectional ball.

10. A humanoid robot, characterized in that, It has a foot structure for a humanoid robot as described in any one of claims 1 to 9.

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