Foot structure for humanoid robot and humanoid robot

Abstract

The invention provides a foot structure for a humanoid robot and the humanoid robot. The foot structure comprises a sole, a heel, a direct drive motor and a flange bearing. The soles are in contact with the ground to realize left-right rotation; the heel is connected with the shank to realize front-back rotation. The direct-drive motor is installed at the front end of the sole and connected with the heel through a motor rotor to control left-right rotation. The flange bearing is installed at the upper end of the heel and connected with the shank to control front-back rotation. The single-ankle and double-ankle conversion mechanism is fixed or released by screws through the through holes in the side faces of the soles and the threaded holes of the heels. When the sole and the heel are loosened, the motor drives the sole to rotate relative to the heel, and the double-ankle function is achieved; and the screw fixation is in a single-ankle state. By means of the design, complexity of traditional double-ankle design is simplified, production cost and time consumption are reduced, adaptability and flexibility of feet are improved, and the robot can better adapt to complex terrains and diversified environments.

Description

Technical Field

[0001] The present invention relates to robot technology, in particular to a foot structure for a humanoid robot and the humanoid robot. Background Art

[0002] With the continuous improvement of human science and technology and the rapid growth of intelligent demand, the research on humanoid robots has gradually become the focus of global academia and industry. As an important branch of the field of robotics, humanoid robots can not only imitate human movements and forms, but also have the potential to adapt to complex environments, showing great application prospects in service, medical care, rescue and other fields. However, the foot design of humanoid robots often involves a variety of physical properties, mechanical structures and control algorithms to achieve a higher level of flexibility, stability and adaptability. Especially in real complex environments, humanoid robots must face different terrains, direction changes and other factors, which puts more stringent requirements on their foot structure.

[0003] Traditional humanoid robot foot designs mostly use a single ankle structure, that is, each foot has only one rotation joint, usually rotating in the front-to-back direction to achieve basic gait control and ground adaptability. This design is relatively simple in robot control and manufacturing because it has fewer structures and a low complexity control system. In addition, since a single rotational degree of freedom is easy to achieve smooth control, the single ankle design has a certain stability and is especially suitable for walking on flat ground. However, the single ankle design also faces certain limitations. Since it only has one degree of freedom, this structure has poor adaptability when dealing with uneven or irregular terrain, cannot make subtle posture adjustments, and cannot cope with sudden directional changes. The gait flexibility of this design is low, so in real applications, single-ankle structure humanoid robots are suitable for scenarios with high requirements for ground flatness or industrial applications with higher requirements for stability, but they are obviously not comprehensive enough in terms of the diversity and complexity of the human environment.

[0004] In contrast, the double-ankle design sets two rotational degrees of freedom for each foot, usually with joints in the front-to-back and left-to-right directions, which can better simulate the multi-dimensional movement pattern of the human ankle joint. This structure provides greater flexibility in movement, especially on complex terrain, uphill or downhill and other uneven surfaces. The double-ankle design can more flexibly adjust the robot's posture to maintain balance and stability. Thanks to the two independent rotational degrees of freedom, the double-ankle robot can achieve a variety of gaits, such as walking on slopes, roll adjustment, and flexible turning in a small space, greatly improving the robot's ability to adapt to a variety of environments.

[0005] However, the double-ankle structure also has significant challenges in design and control. Most existing double-ankle designs use two connecting rods for primary transmission to control the left and right rotation of the ankle. For the double-ankle structure driven in this way, the movement of the connecting rod is no longer planar motion, but three-dimensional motion in space, which requires the use of multiple bearings or joint ball bearings for the connecting rod. The complex structure causes the production cost to continue to rise. In addition, the drive design of the double-link is also accompanied by the complexity of the algorithm solution, and the difficulty of motion control has increased significantly. On the other hand, in the debugging of humanoid robots, although the double ankles have better stability, the control based on reinforcement learning or MPC will also be relatively difficult. Many teams need to start debugging from a single ankle and then advance to a double ankle. In this case, most single ankle structures and double ankle structures are designed and processed separately, which is time-consuming and costly.

[0006] The most common design of a double ankle foot is a double-link design, in which a cross shaft is designed on the foot. The foot can be used to rotate in two directions, front and back, left and right. Then two drive motors are installed on the calf of the humanoid robot, and the cross shaft of the foot is connected by two connecting rods. When one motor rotates and the other does not rotate, the foot will rotate in the left and right directions to achieve the side flip of the foot; when the two motors rotate synchronously, the foot will rotate in the front and back directions to achieve the front and back flip of the foot; when the two motors rotate at the same time and not synchronously, the foot will rotate in both the left and right and front and back directions to achieve the universal rotation of the foot. Its disadvantages are: 1. The double-link drive is a primary structure transmission, and the transmission accuracy and stability are lower than those of direct drive. 2. The structure is complex, the required parts and designs are difficult, and the cost is high. 3. The solution of motion control is extremely complex, and the joint ball bearings used in the connecting rod have infinite solutions during movement, and the motion stability is low.

[0007] Another humanoid robot foot design is a single-ankle foot design, which only has the freedom of rotation in the front-to-back direction. This design uses a single-link primary transmission drive, installs a motor on the calf, and then forms a parallelogram through the connecting rod and the foot, so that the motor drives the foot to rotate forward and backward. Its disadvantages are: 1. This design only has the freedom of rotation in the front-to-back direction, and cannot make the foot rotate in the left-right direction. When the humanoid robot needs to maintain standing stability, it can only be adjusted through the motor of the thigh, and cannot maintain stability by rotating the foot in the left-right direction. 2. When the humanoid robot moves sideways with this design, the foot cannot remain parallel to the ground, resulting in an unsolvable or extremely unstable movement.

[0008] Existing humanoid robot foot designs are mainly divided into single ankle and double ankle designs, and these two designs are independent of each other. The mainstream double parallel connecting rod drive of double ankles also has problems such as instability and complex structure.

[0009] It should be noted that the information disclosed in the above background technology section is only used for understanding the background of the present application, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the invention

[0010] The main purpose of the present invention is to overcome the defects existing in the above-mentioned background technology and provide a foot structure for a humanoid robot and a humanoid robot.

[0011] To achieve the above object, the present invention adopts the following technical solutions:

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

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

[0014] A heel, used to connect with the robot's calf and achieve rotational freedom in the front-back direction;

[0015] A direct drive motor is installed at the front end of the sole of the foot, the motor housing is fixedly connected to the sole of the foot, and the motor rotor extends out of the sole of the foot and is connected to the heel to achieve the rotational freedom of the foot in the left and right directions;

[0016] A flange bearing is installed at the upper end of the heel and connected to the robot shank to achieve rotational freedom of the foot in the front-to-back direction;

[0017] The single-double ankle conversion mechanism includes a through hole on the side of the sole and a threaded hole on the heel, wherein screws are screwed in or loosened to fix or release the relative rotation between the sole and the heel; wherein, when the sole and the heel are loosened, the sole can rotate relative to the heel driven by a motor and is in a double ankle state, and when tightened, the sole cannot rotate relative to the heel and is in a single ankle state.

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

[0019] Furthermore, it also includes: an insole installed at the lower end of the sole of the foot to provide cushioning and anti-slip.

[0020] Furthermore, it also includes: a heavy-duty universal ball, which is arranged between the sole and the heel to assist rotation and provide support.

[0021] Further, the heavy-duty universal ball includes at least two first universal balls and one second universal ball, wherein:

[0022] The first universal ball is installed at a 45° angle in the groove of the semicircular boss of the sole of the foot to provide lateral support;

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

[0024] The balls of the heavy-duty universal ball are all facing upwards to ensure the smooth rotation of the sole of the foot in the left and right directions and reduce friction and wear during the rotation process.

[0025] Furthermore, there are two flange bearings which are relatively installed in the circular groove through holes at the upper end of the heel, with a slight gap between them to prevent false position in the axial direction.

[0026] Furthermore, the insole is made of silicone material, and a groove is provided at the bottom, which is fixedly connected to the sole of 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 problems.

[0028] Furthermore, the rotation limit of the sole is designed to be -45° to 45°, which is achieved by the square bosses arranged on both sides of the rear end of the heel contacting with the heavy universal ball.

[0029] A humanoid robot has the humanoid robot foot structure.

[0030] The present invention has the following beneficial effects:

[0031] The present invention provides a foot structure for a humanoid robot, which achieves significant technical advantages through an innovative single-double ankle conversion method. The foot structure adopts a motor direct drive design, integrates a motor that controls left and right rotation in the foot, realizes the double ankle function, ensures the stability of the drive, and greatly reduces the complexity of the motion control algorithm. Through the single-double ankle conversion mechanism with a through hole set on the side of the sole and a threaded hole set on the heel, it is easy to switch between the single ankle and double ankle states by screwing in or loosening the screws. In the double ankle state, the sole can rotate relative to the heel, providing additional left and right rotation freedom, while in the single ankle state, the sole and the heel are fixed as a rigid body, and the rotor of the motor can no longer drive the sole to rotate. This design not only simplifies the complexity of the traditional double ankle design, reduces production costs and time consumption, but also improves the adaptability and flexibility of the foot, so that the robot can better adapt to complex terrain and diverse environments. In addition, the modular connection, lightweight design and stable heel support structure of the foot structure also significantly improve the overall performance and durability, making the present invention have obvious advantages in improving the walking flexibility and balance ability of humanoid robots.

[0032] Compared with the prior art, the advantages of the embodiments of the present invention are mainly as follows:

[0033] 1. The double ankle design of the foot is realized by using direct motor drive, which greatly simplifies the complexity of the motion control algorithm and makes the foot work more stable and precise.

[0034] 2. The rotation pairs in the front and back and left and right directions are split and integrated. Different from the cross-axis design commonly used in the double ankle design in the prior art, the rotation is more stable, and the gap and virtual position are smaller.

[0035] 3. A simple single-ankle and double-ankle conversion method is designed, so that the foot can switch freely between single ankle and double ankles.

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

[0037] 5. A relatively lightweight integrated design is adopted, integrating single and double ankle conversion devices and left and right rotation limit devices into the sole and heel, avoiding excessive structural components.

[0038] Other beneficial effects of the embodiments of the present invention will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0040] Figure 2 It is an overall exploded view of an embodiment of the present invention.

[0041] Figure 3 The single and double ankle conversion and rotation limit integrated structure diagram of the embodiment of the present invention

[0042] Figure 4 This is a diagram of the mechanical limit structure of the double ankle rotation according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope and application of the present invention.

[0044] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for fixing as well as for coupling or communication.

[0045] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0046] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

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

[0048] The sole 1 is designed to contact the ground and realize the rotational freedom of the foot in the left and right directions. The heel 2 is used to connect with the robot's calf to realize the rotational freedom in the front and back directions.

[0049] The direct drive motor 3 is installed at the front end of the sole 1, and the motor housing is fixedly connected to the sole 1 by screws. The motor rotor extends out of the sole 1 and connects to the heel 2, thereby realizing the rotational freedom of the foot in the left and right directions, and enhancing the transmission accuracy and stability.

[0050] The single-double ankle conversion mechanism includes a through hole 6 on the side of the sole 1 and a threaded hole 7 on the heel 2, which fixes or releases the relative rotation between the sole 1 and the heel 2 by screwing in or loosening a screw; wherein, when the sole 1 and the heel 2 are loosened, the sole 1 can rotate relative to the heel 2 driven by the direct drive motor 3 (through the motor housing) and is in a double ankle state; when tightened, the sole 1 cannot rotate relative to the heel 2 and is in a single ankle state.

[0051] The flange bearing 5 is installed at the upper end of the heel 2 and connected to the robot shank (not shown) to achieve the rotational freedom of the foot in the front-back direction. To ensure stability, there are two flange bearings 5, which are relatively installed in the circular groove through hole at the upper end of the heel 2, with a slight gap between them to prevent false position in the axial direction.

[0052] Preferably, a heavy-duty universal ball 4 is provided between the sole 1 and the heel 2 to ensure smooth rotation and provide stable support. The heavy-duty universal ball 4 includes at least two first universal balls (SP-8 universal balls may be used) and one second universal ball (SP-12 universal ball may be used). The first universal ball is installed at a 45° angle in the groove of the semicircular boss of the sole 1 to provide lateral support; the second universal ball is vertically installed in the groove of the square boss of the sole 1 to provide vertical support. The balls of all heavy-duty universal balls 4 are facing upwards to ensure smooth rotation of the sole 1 in the left and right directions and reduce friction and wear during rotation.

[0053] In addition, the foot structure also includes an insole 8, which is made of silicone material (such as 70A silicone material). The grooves arranged at the bottom of the insole 8 are fixedly connected to the sole 1 by screws to provide cushioning and anti-slip functions.

[0054] The sole 1 and the heel 2 are made of materials with high specific strength and high specific stiffness to increase bending resistance and reduce fatigue problems. The rotation limit of the sole 1 is designed to be -45° to 45°, which is achieved by the square bosses 9 set on both sides of the rear end of the heel 2 and the heavy universal ball 4 to ensure the accuracy and controllability of the foot movement.

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

[0056] An embodiment of the present invention further provides a humanoid robot having the foot structure of any of the aforementioned embodiments.

[0057] The specific embodiments of the present invention are further described below.

[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 is designed with two degrees of freedom, namely front-to-back and left-to-right rotation. The left-to-right rotation is achieved by direct motor drive, and there is a limit design for the left-to-right rotation, and its movement angle is -45° to 45°.

[0060] The key parts of the foot design are the design of the sole 1 and the heel 2. The two are independent and can achieve relative and synchronous movement to achieve the forward and backward rotation of the entire foot and the left and right rotation of the sole 1 alone. The connection between the two is firm and reliable. When selecting materials, materials with high specific strength and high specific stiffness are selected, and a support design is used to increase its bending resistance and reduce its overall fatigue problem.

[0061] The foot design has the characteristics of close integration, and the conversion design of single and double ankles and the limit design of left and right rotation are integrated into the heel 2 and the sole 1, reducing the number of parts and achieving lightweight and high integration.

[0062] In order to realize the movement of both ankles, the foot is designed according to the modular design principle, and the whole is divided into two parts: the sole 1 and the heel 2. Figure 1 The figure shows the designed overall structure of the foot, wherein the heel 2 is a modular component connected to the calf of the humanoid robot, and the sole 1 is a fixed connection component to the direct drive motor 3. Figure 1 The two arrows in the figure respectively indicate the rotation directions of the sole 1 and the heel 2.

[0063] Figure 2 The figure shows an overall exploded view of the foot, including a direct drive motor 3, an insole 8, a sole 1, a heel 2, a heavy-duty universal ball 4, and a flange bearing 5. The direct drive motor 3 is installed at the front end of the sole 1 and is fixedly connected to the housing of the direct drive motor 3 by six screws, so that the rotor of the direct drive motor 3 extends through the hole on the sole 1. The heavy-duty universal ball 4 is divided into two types, two are SP-8 and one is SP-12. The SP-8 is installed at a 45° angle to the groove of the semicircular boss of the sole 1, and the SP-12 is vertically installed in the groove of the square boss of the sole 1, and its balls are all facing upward. The heel 2 is connected to the rotor of the direct drive motor 3 through the four M3 holes on the front circular boss. Here, the motor is reversed, and the structural part fixed to the motor housing, that is, the sole 1, rotates relative to the structural part fixed to the motor rotor, thereby realizing the rotational freedom of the sole 1 of the foot in the left and right directions; the arc-shaped structure below the heel 2 is tangentially connected to the three heavy-duty universal balls 4. When the sole 1 rotates, the three heavy-duty universal balls 4 roll in contact with the arc surface of the heel 2, ensuring the smoothness of the rotation and providing support to avoid the bending of the sole 1 caused by the cantilever beam phenomenon. There are two flange bearings 5, which are relatively installed on the circular groove through hole at the upper end of the heel 2, with a gap of 0.2mm between the two, to prevent the two flange bearings 5 ​​from contacting each other to cause axial hypocrisy, ensuring its stability; the flange bearing 5 is the connecting shaft between the foot and the calf of the humanoid robot, which is used to enable the foot to achieve the rotational freedom in the front and back directions. The insole 8 is installed at the lower end of the sole 1 , and 70A silicone is selected as the 3D printing material, which has the characteristics of anti-slip and cushioning. Several screws are screwed into the grooves set at the bottom to connect with the bottom of the sole 1 .

[0064] Figure 3The integrated structural diagram of single and double ankle conversion and rotation limit is shown. In order to realize the integration of the single and double ankle functions of the foot device and convert them through simple operations, two through holes 6 with a diameter of 3mm and a circular groove with a diameter of 6mm are set on the side of the sole 1. In addition, two threaded holes 7 are set on the side of the circular boss where the heel 2 is fixed to the motor rotor at the position corresponding to the through hole 6. When it is necessary to set the foot device to a single ankle state, only two M3 screws need to be screwed into the side to fix the sole 1 and the heel 2 to each other. At this time, the sole 1 and the heel 2 are fixed as a rigid body, and the motor can no longer drive the sole 1 to rotate, so it is in a single ankle state. When the two screws are not screwed in, the sole 1 is controlled by the motor to rotate, and it is in a double ankle state.

[0065] In the motion control of a humanoid robot, the motion range of each joint needs to be given, and in reality the motion range of the joint also needs to be fixed by mechanical limiters. To achieve a high degree of integration, two square bosses 9 are provided on both sides of the rear end of the heel 2, and the rotation angle is set to ±45°. Figure 4 The diagram of the mechanical limit structure of the double ankle rotation is shown. When the rotation reaches ±45°, the provided boss will contact the SP-12 heavy-duty universal ball 4, preventing further rotation.

[0066] Compared with the traditional robot foot design, the humanoid robot foot structure of the present invention realizes the function of single-double ankle conversion by adopting a motor direct drive design, providing a foot design with stable structure, simplified control algorithm, and easy conversion between single ankle and double ankle states. This design integrates the motor directly into the foot, which not only improves the stability and transmission accuracy of the drive, but also significantly reduces the complexity of the motion control algorithm. Compared with the traditional dual parallel connecting rod drive, the motor direct drive method of the present invention is more stable and reliable, reduces the number of overall components, and optimizes the spatial layout of the humanoid robot calf structure.

[0067] The single-double ankle conversion mechanism of the present invention can easily complete the functional conversion between single ankle and double ankle by using screws through the through holes and threaded holes set on the side of the sole and the heel. In the double ankle state, the motor can drive the sole to rotate relative to the heel, providing additional left and right rotation freedom, and enhancing the robot's adaptability and flexibility to complex terrain. In the single ankle state, the sole and heel are fixedly connected as a rigid body, which simplifies the structure of the foot and improves the stability of the gait. This simple conversion method reduces production costs and time consumption, and eliminates the need for repeated design and processing.

[0068] The foot structure of the present invention realizes the decomposition design of the rotation pair in the front and back and left and right directions, provides stable rotation and limit, and makes the foot movement more precise. The design of the heel support structure avoids the cantilever beam problem of the sole connection part and enhances the anti-bending ability of the structure. The lightweight integrated design integrates the single and double ankle conversion device and the left and right rotation limit device into the sole and heel, avoiding excessive structural parts and further improving the performance and durability of the foot.

[0069] In summary, the foot structure design of the present invention, with its innovative single-double ankle conversion method, stable motor direct drive technology, optimized space layout and lightweight structure, provides an effective solution for improving the adaptability and flexibility of humanoid robots, while simplifying the design and manufacturing process, reducing costs, and providing significant advantages for industrial applications.

[0070] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, it can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of the reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can 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 sole of the foot is used to contact the ground and achieve rotational freedom in the left and right directions; A heel, used to connect with the robot's calf and achieve rotational freedom in the front-back direction; A direct drive motor is installed at the front end of the sole of the foot, the motor housing is fixedly connected to the sole of the foot, and the motor rotor extends out of the sole of the foot and is connected to the heel to achieve the rotational freedom of the foot in the left and right directions; A flange bearing is installed at the upper end of the heel and connected to the robot shank to achieve rotational freedom of the foot in the front-to-back direction; The single-double ankle conversion mechanism includes a through hole on the side of the sole and a threaded hole on the heel, wherein screws are screwed in or loosened to fix or release the relative rotation between the sole and the heel; wherein, when the sole and the heel are loosened, the sole can rotate relative to the heel driven by a motor and is in a double ankle state, and when tightened, the sole cannot rotate relative to the heel and is in a single ankle state.

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

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

4. The humanoid robot foot structure according to any one of claims 1 to 3, characterized in that: Also includes: Heavy-duty universal ball, set between the ball of the foot and the heel, is used to assist rotation and provide support.

5. The humanoid robot foot structure according to claim 4, characterized in that: The heavy-duty universal ball comprises at least two first universal balls and one second universal ball, wherein: The first universal ball is installed at a 45° angle in the groove of the semicircular boss of the sole of the foot to provide lateral support; The second universal ball is vertically mounted on the groove of the square boss of the sole to provide vertical support; The balls of the heavy-duty universal ball are all facing upwards to ensure the smooth rotation of the sole of the foot in the left and right directions and reduce friction and wear during the rotation process.

6. The humanoid robot foot structure according to any one of claims 1 to 5, characterized in that: There are two flange bearings which are relatively installed in the circular groove through holes at the upper end of the heel, with a slight gap between them to prevent false position in the axial direction.

7. The humanoid robot foot structure according to any one of claims 1 to 6, characterized in that: The single and double ankle conversion mechanism secures or releases the rotation between the sole and the heel by screwing in or loosening an M3 screw in a through hole on the side of the sole.

8. The humanoid robot foot structure according to any one of claims 3 to 7, characterized in that: The insole is made of silica gel material, and a groove is arranged at the bottom, which is fixedly connected to the sole of the foot by screwing in screws.

9. The humanoid robot foot structure according to any one of claims 4 to 8, characterized in that: The rotation limit of the sole is designed to be -45° to 45°, which is achieved by the square bosses arranged on both sides of the rear end of the heel contacting with the heavy universal ball.

10. A humanoid robot, characterized in that: A humanoid robot foot structure as claimed in any one of claims 1 to 9.

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