A robot's foot device and a humanoid robot

Abstract

This utility model discloses a foot device for a robot and a humanoid robot. The foot device for a robot includes an instep assembly, a heel assembly, and a toe assembly. The heel assembly is connected to the rear end of the instep assembly, and the toe assembly is connected to the front end of the instep assembly via a first revolute joint. It also includes an elastic device, with a first end connected to the rear of the toe assembly and a second end connected to either the instep assembly or the heel assembly. When the toe assembly rotates relative to the instep assembly, the elastic device is stretched or compressed to provide cushioning. A humanoid robot employing any of the above-described foot devices is also disclosed. The advantages of this utility model are: extremely fast cushioning response speed, extremely high energy absorption efficiency, and more effective protection of the robot's body and joints.

Description

Technical Field

[0001] This utility model relates to the field of robotics technology, specifically to a foot device for a robot and a humanoid robot. Background Technology

[0002] The feet of a humanoid robot are its only part that interacts with the ground, and their design directly determines the robot's motion stability, energy consumption, noise level, and adaptability to complex terrain. An excellent humanoid foot design aims to mimic the biomechanical characteristics of the human foot, particularly achieving a heel-toe gait. Compared to the rigid knee-to-toe gait, this gait pattern offers significant advantages such as lower energy consumption, a more natural gait, less noise, and less impact on the robot's body.

[0003] Currently, the industry's designs for humanoid robot feet are mainly divided into the following categories: Rigid monolithic foot: This is the simplest and most common design, where the foot is a rigid monolith, usually a flat plate or a simple curved surface structure. Its advantages are simple structure, reliability, and low cost. However, its disadvantages are extremely prominent: it cannot absorb impact upon landing, requiring the robot's leg joints (such as the knee and ankle joints) to actively flex and extend to cushion the impact, resulting in high motor load and energy consumption; it cannot adapt to uneven ground, exhibiting poor grounding; and it is difficult to achieve a natural heel-toe gait, resulting in a stiff and unnatural walking posture.

[0004] Simple articulated feet: To improve adaptability, some designs introduce simple articulated joints into the foot. For example, the forefoot is articulated from the heel, and a simple spring element may be added. This type of design improves ground contact and cushioning to some extent, but it usually has only one degree of freedom (usually only in the pitch direction), making it difficult to cope with complex situations such as ground tilt (roll direction), and its biomimetic effect and adaptability are still limited.

[0005] Complex multi-DOF bionic feet: To highly simulate the function of human feet, more complex designs have emerged. For example, CN118928586A discloses a humanoid mechanical foot for humanoid robots. Such designs typically include a split arch structure, toes that achieve multiple degrees of freedom via a cross axis, and multiple independent elastic cushioning components and torsion spring return mechanisms.

[0006] While such complex designs functionally achieve better buffering and multi-dimensional terrain adaptation, they also introduce new problems: Complex structure: It contains a large number of parts (such as split arch, cross shaft, multiple torsion spring protective shells, multiple sliding bushings, etc.), resulting in high manufacturing, assembly and maintenance costs.

[0007] Heavy weight: The complex structure inevitably leads to increased weight, which contradicts the design goal of lightweight robots and increases the load on the leg drive unit and overall energy consumption.

[0008] The difficulty of control is indirectly increased: Although it is a passive adaptation, the large number of joints and elastic elements makes the dynamic model of the foot more complex, which puts forward higher requirements for the state estimation and control strategy of the whole machine.

[0009] The force transmission path is long and inefficient: the impact force needs to pass through a multi-stage linkage structure to be transmitted to the main elastic buffer element, resulting in energy loss and an insufficiently direct response.

[0010] In summary, those skilled in the art have been seeking a balance: how to greatly simplify the mechanical structure, reduce weight and cost, and optimize force transmission efficiency while ensuring or even improving biomimetic functions (buffering, terrain adaptation). This is precisely the core technical problem that this invention aims to solve. Utility Model Content

[0011] The purpose of this invention is to overcome the shortcomings of the existing technology and specifically solve the problems of redundant and heavy complex bionic foot structures and single function of simple feet. It provides a robot foot device and humanoid robot with simple and efficient structure, good cushioning effect, strong terrain adaptability and easy control.

[0012] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution: A foot device for a robot includes an instep assembly, a heel assembly, and a toe assembly, wherein the heel assembly is connected to the rear end of the instep assembly, and the toe assembly is connected to the front end of the instep assembly via a first revolute joint. It also includes an elastic device, the first end of which is connected to the rear of the toe assembly, and the second end of which is connected to the instep assembly or the heel assembly; when the toe assembly rotates relative to the instep assembly, the elastic device is stretched or compressed to provide cushioning.

[0013] In the foot device of the robot described above, the second end of the elastic device is connected to the connection between the instep assembly and the heel assembly.

[0014] In the foot device of the robot described above, the rear bottom of the instep assembly is connected to the front top of the heel assembly via a second rotating joint; the heel assembly is provided with a first limiting part, and the instep assembly is provided with a second limiting part, the second limiting part abutting against the first limiting part to limit the upward rotation of the instep assembly relative to the heel assembly.

[0015] In the foot device of the robot described above, the first revolute joint is disposed at the middle of the instep assembly and the toe assembly.

[0016] In the aforementioned foot device of a robot, the first rotating joint includes a transfer groove disposed on the toe assembly and a transfer part disposed on the instep assembly and extending into the transfer groove. The transfer part is rotatably connected to the groove wall of the transfer groove via a rotating shaft. The cross-sectional structure of the groove opening is smaller inside and larger outside to limit the range of motion of the transfer part within the groove, thereby limiting the rotation amplitude of the toe assembly relative to the instep assembly.

[0017] In the aforementioned foot device of a robot, there are two sets of the first rotating joints, which are spaced apart, and the rotation axes of the two sets of the first rotating joints coincide.

[0018] In the foot device of the robot described above, the elastic device is suspended below the instep assembly, and the horizontal height of the elastic device is higher than the ground contact plane of the toe assembly and the heel assembly, so as to avoid the elastic device from contacting the ground.

[0019] In the foot device of the robot described above, the instep assembly, heel assembly, and toe assembly are all hollow structures.

[0020] In the aforementioned foot device of a robot, the instep assembly is provided with an upwardly extending first connecting portion, and the heel assembly is provided with an upwardly extending second connecting portion. The first connecting portion and the second connecting portion are arranged at intervals in the front-back direction. Both the first connecting portion and the second connecting portion are provided with connecting holes, and the axes of the two connecting holes coincide, for connecting with the robot's lower leg component to jointly form a rotatable ankle structure.

[0021] A humanoid robot was also disclosed, employing the foot device described in any of the above-mentioned schemes. With this foot device, the robot can achieve a heel-toe gait similar to that of humans, significantly reducing walking energy consumption and resulting in a more natural and fluid posture. The passive cushioning of the feet allows the robot to maintain better balance and stability when facing uneven ground.

[0022] Compared with the prior art, the advantages of this utility model are: The first revolute joint provides the toe component with the freedom of rotation relative to the instep component, while the elastic device acts as both the power source and a damper for this rotation. When the foot unit contacts the ground, the toe component rotates upwards around the first revolute joint due to the ground reaction force, while the elastic device is stretched (or compressed). This process absorbs impact energy and stores elastic potential energy. During the push-off phase, the elastic device releases the stored energy, assisting the toe in rotating downwards, resulting in a natural push-off motion. This passive, elastically driven rotation perfectly replicates the essence of human walking. Compared to rigid feet, which rely on complex control of active joints such as the knee and ankle to mimic this movement, this design significantly reduces energy consumption and produces a more natural and fluid walking posture.

[0023] The first end of the elastic device is connected to the rear of the toe assembly, and the second end is connected to the instep assembly or the heel assembly. When the toes touch the ground, the impact force acts first on the toe assembly. Because the first end of the elastic device is connected here, energy can be transferred to the elastic device instantly and directly. The second end of the elastic device is directly connected to the instep or heel assembly, forming a stable force fulcrum. This point-to-point energy transfer path is the shortest and most direct, avoiding energy loss, hysteresis, and stress concentration caused by multiple joints and links in complex structures. Therefore, this design has an extremely fast buffer response speed and extremely high energy absorption efficiency, which can more effectively protect the robot body and joints.

[0024] The entire cushioning mechanism consists of only one revolute joint and one elastic device, eliminating the separate foot arch, cross shaft, multiple torsion spring protective shells, sliding bushings, and other components found in existing technologies. Through high functional integration, the two core tasks of rotation and cushioning are accomplished with a minimal number of parts. This sharp reduction in the number of parts directly leads to a significant decrease in the overall mass of the foot, which not only meets the design goal of lightweight robots but also reduces the load on the leg drive motors, further lowering the overall energy consumption of the machine.

[0025] Furthermore, the second end of the elastic device is connected to the connection point between the instep assembly and the heel assembly. By utilizing the existing connection point between the instep and heel as the mounting point, there is no need to design and manufacture additional mounting brackets or complex connection structures for the elastic device. This reduces the number of parts, lowers the overall weight and complexity of the foot, and perfectly aligns with the goals of lightweight and low cost in robot design.

[0026] Furthermore, the rear bottom of the instep assembly is connected to the front top of the heel assembly via a second revolute joint; the heel assembly has a first limiting part, and the instep assembly has a second limiting part, which abuts against the first limiting part to limit the upward rotation of the instep assembly relative to the heel assembly. The cooperation of the first and second limiting parts ensures that the foot will not collapse and become unstable when the robot pushes off the ground or stands up, providing a reliable support structure for the entire leg.

[0027] Furthermore, the first revolute joint is located in the middle of the instep assembly and the toe assembly. The center of rotation is located in the middle, ensuring that the lever arm from the point of application of the elastic force (at the rear of the toe assembly) to the center of rotation is relatively balanced with the lever arm from the point of application of the ground reaction force (at the front of the toe assembly) to the center of rotation. This balanced torque relationship allows the elastic device to generate sufficient torque to drive the toe rotation with relatively small deformation, resulting in higher energy conversion efficiency and less effort.

[0028] Furthermore, the first rotating joint includes a transition groove disposed on the toe assembly and a transition part disposed on the instep assembly and extending into the transition groove. The transition part is rotatably connected to the groove wall of the transition groove via a rotating shaft. The cross-sectional structure of the transition groove opening is smaller on the inside and larger on the outside to limit the range of motion of the transition part within the groove, thereby limiting the rotation amplitude of the toe assembly relative to the instep assembly. By employing a purely mechanical, passive limiting method to control the rotation of the toe assembly relative to the instep assembly, and utilizing the shape of the groove opening to precisely limit the toe rotation angle, the movement of each step is ensured to be within the designed safety range, improving gait consistency and predictability.

[0029] Furthermore, there are two sets of the first revolute joint, spaced apart, with the rotation axes of the two sets of first revolute joints coinciding. This structure transforms single-point support into two-point support, greatly enhancing the bending and torsional stiffness of the revolute joint. This makes the movement trajectory of the toe more stable and precise when rotating relative to the instep, preventing undesirable lateral swaying. It is particularly suitable for applications where the robot's foot requires precise and reliable ground contact.

[0030] Furthermore, the elastic device is suspended below the instep assembly, and its horizontal height is higher than the ground contact plane of the toe and heel assemblies to avoid contact with the ground. Placing the elastic device above the ground plane reduces the possibility of the robot colliding, tripping, or being squeezed by obstacles such as the ground, stones, and gaps when walking, turning, or going up and down stairs. It effectively prevents the elastic device from experiencing performance degradation or breakage due to wear and corrosion, significantly extending its service life and reducing maintenance requirements.

[0031] Furthermore, the instep assembly, heel assembly, and toe assembly are all hollow structures. The hollow structure can effectively reduce the weight of the parts. As the end effector of the robot's legs, the weight reduction of the foot can significantly reduce the rotational inertia of the hip and knee joints. This means that the drive motor can drive the leg movement with less torque and energy consumption, thereby improving the robot's walking speed, acceleration ability, and endurance.

[0032] Furthermore, the instep assembly has an upwardly extending first connecting portion, and the heel assembly has an upwardly extending second connecting portion. The first and second connecting portions are spaced apart in the front-to-back direction. Both the first and second connecting portions have connecting holes with their axes coinciding, for connecting with the robot's lower leg components to jointly form a rotatable ankle structure. The two spaced-ahead connecting portions form a dual-support structure, which, compared to a single connecting portion, can more evenly distribute the pressure and torque transmitted from the lower leg to the foot, avoiding stress concentration at the ankle connection point caused by single-point force, significantly improving overall connection strength and fatigue resistance, and adapting to high-intensity movement scenarios such as robot walking and pushing off the ground. Attached Figure Description

[0033] Figure 1 This is a perspective view of a robot's foot device according to the present invention; Figure 2 This is a schematic diagram of the toe component in this utility model; Figure 3 This is a schematic diagram of the instep assembly in this utility model; Figure 4 This is a schematic diagram of the heel component in this utility model; Figure 5 This is an exploded view of the foot device of a robot according to the present invention; Figure 6 This is a front view of the foot device of a robot according to the present invention; Figure 7 This is a structural schematic diagram of a humanoid robot according to the present invention.

[0034] The attached figures are labeled as follows: Foot instep assembly 210, second limiting part 211, adapter part 212, first connecting part 213; Heel assembly 220, first limiting part 221, second connecting part 222, connecting hole 223; Toe assembly 230, adapter slot 231; First rotary joint 240; Elastic device 250; Second rotary joint 260; Lower leg part 300. Detailed Implementation

[0035] A foot device for a robot includes an instep assembly 210, a heel assembly 220, and a toe assembly 230. The heel assembly 220 is connected to the rear end of the instep assembly 210, and the toe assembly 230 is connected to the front end of the instep assembly 210 via a first revolute joint 240. It also includes an elastic device 250, with a first end connected to the rear of the toe assembly 230 and a second end connected to the instep assembly 210 or the heel assembly 220; when the toe assembly 230 rotates relative to the instep assembly 210, the elastic device 250 is stretched or compressed to provide cushioning.

[0036] The first revolute joint 240 provides the toe component 230 with the freedom of rotation relative to the instep component 210, while the elastic device 250 serves as both the power source and a damper for this rotation. When the footwork contacts the ground, the toe component 230 rotates upwards around the first revolute joint 240 due to the ground reaction force, while the elastic device 250 is stretched (or compressed). This process absorbs impact energy and stores elastic potential energy. During the push-off phase, the elastic device 250 releases the stored energy, assisting the toes in rotating downwards, resulting in a natural push-off motion. This passive, elastically driven rotation perfectly replicates the essence of human walking. Compared to rigid feet, which rely on complex control of active joints such as the knee and ankle to mimic this movement, this design significantly reduces energy consumption and produces a more natural and fluid walking posture.

[0037] The first end of the elastic device 250 is connected to the rear of the toe assembly 230, and the second end of the elastic device 250 is connected to the instep assembly 210 or the heel assembly 220. When the toes touch the ground, the impact force is first applied to the toe assembly 230. Because the first end of the elastic device 250 is connected here, energy can be instantly and directly transferred to the elastic device 250. The second end of the elastic device 250 is directly connected to the instep or heel assembly 220, forming a stable force fulcrum. This point-to-point energy transfer path is the shortest and most direct, avoiding energy loss, hysteresis, and stress concentration caused by multi-joint and multi-link transmission in complex structures. Therefore, the buffer response speed of this design is extremely fast, the energy absorption efficiency is extremely high, and it can more effectively protect the robot body and joints.

[0038] The entire cushioning mechanism consists of only one revolute joint and one elastic device 250, eliminating the separate foot arch, cross shaft, multiple torsion spring protective shells, sliding bushings, and other components found in existing technologies. Through high functional integration, the two core tasks of rotation and cushioning are accomplished with a minimal number of parts. This sharp reduction in the number of parts directly leads to a significant decrease in the overall mass of the foot, which not only meets the design goal of lightweight robots but also reduces the load on the leg drive motors, further lowering the overall energy consumption of the machine.

[0039] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0040] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "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 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.

[0041] 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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0043] See Figures 1 to 7This invention relates to an embodiment of a robot foot device. The robot foot device mainly simulates the structure of a human foot, including an instep assembly 210, a heel assembly 220, and a toe assembly 230. The heel assembly 220 is connected to the rear end of the instep assembly 210, and the toe assembly 230 is connected to the front end of the instep assembly 210 through a first rotating joint 240. The heel assembly 220 and the toe assembly 230 are in contact with the ground as two force points. The instep assembly 210 is like a bridge built on the heel assembly 220 and the toe assembly 230. Therefore, in this embodiment, the rear bottom surface of the instep assembly 210 is connected to the front top surface of the heel assembly 220, and the front bottom surface of the instep assembly 210 is rotatably connected to the top surface of the toe assembly 230.

[0044] The foot device also includes an elastic device 250. The first connecting end of the elastic device 250 is connected to the rear of the toe assembly 230, and the second connecting end is connected to the instep assembly 210 or the heel assembly 220. Since the toe assembly 230 is connected to the instep assembly 210 via a first revolute joint 240, the toe assembly 230 can rotate relative to the instep assembly 210, creating an effect similar to a toe. When the toe assembly 230 rotates relative to the instep assembly 210, the elastic device 250 is stretched or compressed to provide cushioning. In other words, the elastic device 250 functions similarly to a plantar fascia. The elastic device 250 can be a component with elastic deformation and the ability to generate restoring force, such as a compression spring, tension spring, or rubber band. In this embodiment, for ease of explanation, a tension spring will be used as an example of the elastic device 250, and the elastic device 250 will be stretched to provide cushioning when the toe assembly 230 rotates relative to the instep assembly 210.

[0045] When the footwork contacts the ground, the toe assembly 230 rotates upward around the first revolute joint 240 due to the ground reaction force, stretching the elastic device 250. This process absorbs impact energy and stores elastic potential energy. During the push-off phase, the elastic device 250 releases the stored energy, assisting the toes in rotating downward, forming a natural push-off motion. This passive, elastically driven rotation perfectly replicates the essence of human walking.

[0046] Furthermore, the second end of the elastic device 250 is connected to the connection point between the instep assembly 210 and the heel assembly 220. In humanoid foot devices, the instep assembly 210 is typically a structure mounted above the heel assembly 220 and the toe assembly 230. Therefore, the connection point between the instep assembly 210 and the heel assembly 220 is naturally higher in vertical height than the ground contact plane of the toe assembly 230 and the heel assembly 220. Connecting the upper end of the elastic device 250 to this point means that its starting point is set at a higher position. This ensures that the elastic device 250 can be suspended in the air in its natural state, maintaining a sufficient safe distance from the ground. By utilizing the existing connection point between the instep assembly 210 and the heel assembly 220 as the mounting point, there is no need to design and manufacture additional mounting brackets or complex connection structures for the elastic device 250. This reduces the number of parts, lowers the overall weight and complexity of the foot, and perfectly aligns with the goals of lightweight and low cost in robot design. Specifically, the second end of the elastic device 250 can be fixed to the connection between the instep assembly 210 and the heel assembly 220 by welding or bonding, or it can be fixed to the connection between the instep assembly 210 and the heel assembly 220 by using a hook. In this embodiment, the instep assembly 210 and the heel assembly 220 are connected by a second rotating joint 260, that is, there is a rotating shaft connecting the instep assembly 210 and the heel assembly 220. Therefore, the second end of the elastic device 250 can also be directly hung on the rotating shaft to fix the second end of the elastic device 250.

[0047] Since the rear bottom of the instep assembly 210 and the front top of the heel assembly 220 are connected by a second revolute joint 260, it is necessary to prevent the arch of the foot from collapsing when the robot stands. That is, when the robot stands, the instep assembly 210 and the heel assembly 220 need to maintain a certain relative position for support. Therefore, a first limiting part 221 is provided on the heel assembly 220, and a second limiting part 211 is provided on the instep assembly 210. The second limiting part 211 abuts against the first limiting part 221 to limit the upward rotation of the instep assembly 210 relative to the heel assembly 220. In this embodiment, the first limiting part 221 is located at the top front end of the heel assembly 220 next to the second rotating joint 260, and the second limiting part 211 is located at the bottom rear end of the instep assembly 210 next to the second rotating joint 260. That is, the bottom rear end of the instep assembly 210 extends slightly towards the heel assembly 220 to form the second limiting part 211, which abuts against the top front end of the heel assembly 220, limiting the upward rotation of the instep assembly 210. The cooperation of the first limiting part 221 and the second limiting part 211 ensures that the foot will not collapse and become unstable when the robot pushes off the ground or stands, providing a reliable support structure for the entire leg. When the instep tends to lean backward, the limiting parts immediately make contact, providing rigid support and directly transmitting torque to the heel and the ground. This ensures that during the support phase, the foot device can provide a stable and reliable platform to bear weight, which is the foundation for achieving a stable gait (especially static standing).

[0048] Based on the above embodiment, the first revolute joint 240 is located at the middle of the instep assembly 210 and the toe assembly 230, that is, the front end of the foot assembly is rotatably connected to the middle of the toe assembly 230. When the toe touches the ground, the ground reaction force acts on the front end of the toe. This force generates a torque around the first revolute joint 240 (fulcrum) that causes the toe to rotate upward. At the same time, the elastic device 250 is connected to the rear of the toe, generating a tensile torque that resists rotation. If the hinge point is too far forward (close to the front end of the toe), the lever arm is very short, requiring a large ground impact force to drive the toe to rotate, resulting in a sluggish cushioning response, and the deformation of the elastic device 250 will be very small, resulting in poor cushioning effect. If the hinge point is too far back (close to the instep), the lever arm is very long, the toe rotation is too sensitive, which may lead to poor stability, and the deformation of the elastic device 250 will be too large, possibly exceeding its normal operating range. The hinge point in the middle allows the lever arm length from the point of force application (the front of the toe) to the fulcrum (the first rotating joint 240), and from the fulcrum to the point of force application (the connection point of the elastic device 250 at the toe) to reach a balance. A small ground impact can effectively initiate the rotation of the toe and the deformation of the elastic device 250. The response is rapid, and the impact kinetic energy can be absorbed more fully and smoothly by the elastic device 250 (stored as potential energy) and effectively released (rebound) during the push-off phase, which helps with walking and improves energy efficiency.

[0049] Furthermore, the first rotating joint 240 includes a transition groove 231 disposed on the toe assembly 230 and a transition portion 212 disposed on the instep assembly 210 and extending into the transition groove 231. The transition portion 212 is rotatably connected to the groove wall of the transition groove 231 via a rotating shaft, thus enabling the toe assembly 230 to rotate relative to the instep assembly 210. The cross-sectional structure of the opening of the transition groove 231 is designed to be smaller inside and larger outside to limit the range of motion of the transition portion 212 within the groove, thereby limiting the rotation amplitude of the toe assembly 230 relative to the instep assembly 210. The transition groove 231 serves as both a bearing seat constituting the rotating joint and a limiting mechanism. When the toe rotates to a preset angle, the transition portion 212 contacts the inner wall of the opening of the transition groove 231, and the movement is immediately stopped, thereby limiting the rotation of the toe assembly 230 relative to the instep assembly 210 within the preset angle. This solution uses a purely mechanical, passive limiting method to control the rotation of the toe component 230 relative to the instep component 210. By utilizing the shape of the slot, it precisely limits the toe rotation angle, ensuring that each step is within the designed safety range and improving the consistency and predictability of the gait.

[0050] Furthermore, there are two sets of first revolute joints 240, spaced apart. For example, the two sets of first revolute joints 240 are located on the left and right sides of the toe assembly 230 in the width direction, respectively, and the rotation axes of the two sets of first revolute joints 240 coincide. If there is only one transition part 212 (single-sided support), when the toe is subjected to force, the rotating shaft and the entire hinge structure act like a cantilever beam, with the root (support point) bearing a huge bending moment, which is prone to deformation, wear, or even failure. The two transition parts 212 with coincident axes form a double support point, which changes the working mode of the rotating shaft from a cantilever beam to a simply supported beam. The load is evenly distributed on the two support points, which greatly improves the bending stiffness, torsional stiffness, and overall stability of the revolute joint. This is crucial for robot feet that need to withstand complex ground impacts.

[0051] Based on the above embodiment, the elastic device 250 is suspended below the instep assembly 210, and its horizontal height is higher than the ground contact plane of the toe assembly 230 and the heel assembly 220 to avoid contact between the elastic device 250 and the ground. The first end of the elastic device 250 can be connected to a position slightly above the tail of the toe assembly 230, so that the side of the elastic device 250 near the toe assembly 230 is higher than the ground. The second end of the elastic device 250 is connected at the intersection of the heel assembly 220 and the instep assembly 210, where the horizontal height of the instep assembly 210 is higher than that of the heel assembly 220. That is, the second end is connected to a position slightly above the front end of the heel assembly 220, similarly ensuring that the side of the elastic device 250 near the heel assembly 220 is higher than the ground. By placing the elastic device 250 above the ground plane, the possibility of the robot being collided with, tripped over, or squeezed by obstacles such as the ground, stones, and gaps when walking, turning, or going up and down stairs is reduced. This effectively prevents the elastic device 250 from experiencing performance degradation or breakage due to wear and corrosion, significantly extending its service life and reducing maintenance requirements.

[0052] The instep assembly 210, toe assembly 230, and heel assembly 220 of the entire foot device can all adopt a hollow structure to reduce the overall weight. The specific location and size of the hollow structure can be generated through methods such as topology optimization to mimic the shape of a biological skeleton, cleverly distributing the material along the paths that bear the most stress. While significantly reducing weight, the structure retains or even optimizes its strength and stiffness in key directions, achieving both lightness and strength.

[0053] like Figure 1 , Figure 6 , Figure 7As shown, in this embodiment, the instep assembly 210 has an upwardly extending first connecting portion 213, and the heel assembly 220 has an upwardly extending second connecting portion 222. The first connecting portion 213 is in front, and the second connecting portion 222 is behind, forming a front-to-back spacing arrangement. Both connecting portions have connecting holes 223, and the axes of the two connecting holes 223 coincide, for connecting with the robot's lower leg assembly 300 to jointly form a rotatable ankle structure. Traditional designs typically use a single centralized connection point (such as a single bearing seat) to connect the lower leg and foot. However, this solution creates two upwardly extending connecting portions on the foot, spaced apart in the front-to-back direction, which, after connecting with the lower leg, form a two-point supported ankle structure. When a robot walks or turns on uneven ground, its feet are subjected to enormous torsional loads. A single-point connected ankle relies on a single bearing and connecting structure to resist all torsion, making it a weak point in rigidity. This design's two-point support structure, with its spaced-out arrangement, forms a stable torque that effectively resists torsional moments, significantly improving the rigidity of the ankle and even the entire leg. This architecture allows the instep assembly 210 and heel assembly 220 to be mechanically relatively independent; they are connected by a common ankle axis, yet can have relatively independent movement tendencies around that axis.

[0054] This embodiment also discloses a humanoid robot employing any of the above-described footwork devices. With this footwork device, the robot can achieve a human-like heel-toe gait, significantly reducing walking energy consumption and resulting in a more natural and fluid posture. The passive cushioning of the feet enables the robot to maintain better balance and stability when facing uneven ground.

[0055] The above description is only a specific embodiment of the present utility model, but the technical features of the present utility model are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present utility model are covered by the patent scope of the present utility model.

Claims

1. A foot device for a robot, comprising an instep assembly, a heel assembly, and a toe assembly, wherein the heel assembly is connected to the rear end of the instep assembly, and the toe assembly is connected to the front end of the instep assembly via a first revolute joint, characterized in that: It also includes an elastic device, the first end of which is connected to the rear of the toe assembly, and the second end of which is connected to the instep assembly or the heel assembly; When the toe assembly rotates relative to the instep assembly, the elastic device is stretched or compressed to provide cushioning.

2. The foot device for a robot according to claim 1, characterized in that: The second end of the elastic device is connected to the connection between the instep assembly and the heel assembly.

3. The foot assembly of claim 1, wherein: The rear bottom of the instep assembly is connected to the front top of the heel assembly via a second rotating joint; the heel assembly is provided with a first limiting part, and the instep assembly is provided with a second limiting part, the second limiting part abutting against the first limiting part to limit the upward rotation of the instep assembly relative to the heel assembly.

4. The foot assembly of claim 1, wherein: The first revolute joint is located at the middle of the instep assembly and the toe assembly.

5. The foot assembly of claim 4, wherein: The first rotating joint includes a transition groove disposed on the toe assembly and a transition part disposed on the instep assembly and extending into the transition groove. The transition part is rotatably connected to the groove wall of the transition groove via a rotating shaft. The cross-sectional structure of the groove opening is smaller inside and larger outside to limit the range of motion of the transition part in the groove, thereby limiting the rotation amplitude of the toe assembly relative to the instep assembly.

6. The foot assembly of claim 5, wherein: The first rotating joint has two sets and is spaced apart, with the rotation axes of the two sets of the first rotating joint coinciding.

7. The foot assembly of claim 1, wherein: The elastic device is suspended below the instep assembly, and its horizontal height is higher than the ground contact plane of the toe assembly and heel assembly to avoid contact between the elastic device and the ground.

8. The foot assembly of claim 1, wherein: The instep assembly, heel assembly, and toe assembly are all hollow structures.

9. The foot assembly of claim 1, wherein: The instep assembly has an upwardly extending first connecting portion, and the heel assembly has an upwardly extending second connecting portion. The first connecting portion and the second connecting portion are arranged at intervals in the front-back direction. Both the first connecting portion and the second connecting portion have connecting holes with their axes overlapping, which are used to connect with the robot's lower leg component to jointly form a rotatable ankle structure.

10. A humanoid robot, characterized by, The foot device according to any one of claims 1 to 9.

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