A robotic bionic foot having a human-like arch structure

Abstract

The application discloses a robot bionic foot with a human foot arch structure, which comprises a sole mechanism, the sole mechanism comprises front soles, middle soles and rear soles which are sequentially and movably connected, the bottom of a calf rod is movably connected with the middle soles of the sole mechanism through an ankle ball joint; the front end of the rear soles is rotatably connected with the rear end of the middle soles through a rear rotating shaft, the bottom of the rear soles is elastically connected with the bottom of the middle soles through a rear stretching spring, and the rear elastic supporting mechanism rotatably connected with the calf rod is used to elastically pull up the rear soles; the front soles comprise two front forks, the rear end of the two front forks is rotatably connected with the front end of the middle soles through a front rotating shaft, the two front forks are elastically connected through a front stretching spring, the top of the two front forks is connected with the calf rod through a front elastic supporting mechanism, and the front elastic supporting mechanism is used to drive the two front forks of the front soles to realize opening and closing movement. The robot bionic foot has the advantages that the robot bionic foot can adapt to complex and changeable terrains and walk more stably in a human gait.

Description

Technical Field

[0001] This invention relates to the field of robotics, and more particularly to a bionic foot for robots with a human-like arch structure. Background Technology

[0002] With the development of information and industrial technologies, intelligent robots have become an important research field. In modern industry, robots are already able to assist or replace human labor in certain mechanical and high-risk tasks, such as mechanical assembly, painting, component welding, and sol-gel molding. Robots are also present in many other fields, including medical rescue, scientific research and exploration, and military defense. In particular, in 2023, a global research boom in humanoid robots emerged, with various types of humanoid robots appearing one after another.

[0003] Humanoid robots are robots designed to mimic the structure of the human body. Compared to traditional wheeled and tracked robots, they have more degrees of freedom, nonlinear motion postures, and dynamic stability. They can adapt to complex ground conditions during movement, have greater flexibility and interactivity, and are better able to meet the needs of daily human production and life, thus having broad application prospects.

[0004] Humanoid robots walk using a bipedal locomotion system, and the biggest challenge they face is maintaining stability and balance. During walking, the impact of the feet on the ground can damage the robot's components and sensors, and may also cause the robot to lose its balance and fall.

[0005] Most current bipedal robots employ a large, flat foot design, such as the Japanese robots ASIMO and HRP-2. This flat design keeps the soles of the feet level, allowing them to firmly contact the flat ground and stand stably. However, this flat design presents several inconveniences when moving on uneven surfaces. When a flat foot steps on a raised area, only part of it contacts the ground, leaving the rest suspended. When the other foot lifts, the robot's entire weight shifts to the foot on the raised area, causing instability, wobbling, or even a fall. The same issue occurs when encountering depressions in the ground, with the foot not making proper contact and remaining suspended, leading to instability. Therefore, the flat foot design is only suitable for flat surfaces, such as business meeting rooms, and is unsuitable for complex and varied terrain, thus limiting the application range of bipedal robots.

[0006] In addition to the aforementioned difficulty in adapting to terrain, the flat-footed design also presents other problems. For example, the center of gravity dynamically shifts during movement: humanoid robots may experience a single leg dangling in the air during walking, and in this area, the robot shifts its center of gravity towards the foot in contact with the ground to maintain balance. Furthermore, the current flat-footed design of humanoid robots is relatively narrow, requiring repeated pacing to adjust the robot's posture. The short distance between the two feet restricts large strides, limiting the flexibility of humanoid robot movement. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a bionic foot for robots with a human-like arch structure, so as to adapt to complex and changing terrain and walk more stably with a human-like gait.

[0008] This invention is achieved through the following technical solution:

[0009] A robotic bionic foot with a human-like arch structure includes a foot mechanism connected to a lower leg rod.

[0010] The foot mechanism includes a forefoot, a midfoot, and a heel that are movably connected in sequence. The bottom of the lower leg bar is movably connected to the midfoot of the foot mechanism via an ankle ball joint.

[0011] The front of the heel is rotatably connected to the rear of the midfoot via a rear rotation axis. The axis of the rear rotation axis extends axially in the left and right directions. The bottom of the heel is elastically connected to the bottom of the midfoot via a rear tension spring, which provides elastic downward pull to the heel. The top of the heel is connected to the lower leg bar via a rear elastic support mechanism. The upper and lower ends of the rear elastic support mechanism are rotatably connected to the middle section of the lower leg bar and the heel, respectively, which provides elastic upward pull to the heel.

[0012] The forefoot includes two forks arranged side-by-side. The rear ends of the two forks are rotatably connected to the front of the midfoot via a front rotation axis extending vertically. The two forks are elastically connected by a front tension spring. The tops of the two forks are connected to the lower leg rod via a front elastic support mechanism. The front elastic support mechanism includes an upper elastic support rod and two lower elastic support rods. The fixed end of the upper elastic support rod is rotatably connected to the middle section of the lower leg rod via a first rotation axis extending horizontally. The movable end of the upper elastic support rod has a connecting rod extending horizontally. The fixed ends of the two lower elastic support rods are rotatably connected to the left and right ends of the connecting rods via a second rotation axis extending forward and backward. Each fork has a sliding shaft, and the movable ends of the two lower elastic support rods slide in contact with the sliding shafts of the two forks. The movable ends of the two lower elastic support rods drive the two forks of the forefoot to open and close.

[0013] As a preferred embodiment of the aforementioned bionic foot for robots, the bottom of the midfoot is concave to form a longitudinal arch, and the rear ends of the two forks of the forefoot are respectively connected to the midfoot, forming a concave lateral arch by combining the gap between the two forks.

[0014] As a preferred embodiment of the aforementioned bionic foot for robots, the front fork is provided with a lug at the rear end and a U-shaped connecting part at the front end of the midfoot. The lug is embedded in the groove of the connecting part at the front end of the midfoot. The front rotation shaft passes through both the connecting part and the lug simultaneously to achieve a rotational connection between the front fork and the midfoot. An elastic body is provided in the gap between the upper and lower sides of the lug and the connecting part of the midfoot to provide elastic support for the upper and lower ends of the lug.

[0015] As a preferred embodiment of the aforementioned bionic foot for robots, the upper elastic support rod and the two lower elastic support rods in the front elastic support mechanism are all spring support rods.

[0016] As a preferred embodiment of the aforementioned bionic foot for robots, the rear elastic support mechanism is a rear spring support rod. The fixed end of the rear spring support rod is rotatably connected to the middle section of the lower leg rod through a third rotating shaft, and the movable end of the rear spring support rod is rotatably connected to the middle section of the rear foot through a fourth rotating shaft. The axes of the third and fourth rotating shafts both extend in the left-right direction.

[0017] As a preferred embodiment of the aforementioned bionic foot for robots, the hind foot has an overall U-shaped structure with an open front end. The two ends of the front end of the hind foot are rotatably connected to the rear end of the middle foot via a rear rotation axis. The movable end of the rear spring support rod is embedded in the hollow part of the hind foot.

[0018] As a preferred embodiment of the aforementioned bionic foot for the robot, the front ends of the two forks are rotatably connected to toes, and the rear ends of the toes are rotatably connected to the front ends of the forks via a fifth rotating shaft. A torsion spring is provided between the fifth rotating shaft and the toe mounting hole.

[0019] As a preferred embodiment of the aforementioned bionic foot for robots, the sliding shaft is provided with limiting structures at both ends to limit the sliding stroke of the lower elastic support rod.

[0020] As a preferred embodiment of the aforementioned bionic foot for robots, support pads are provided on the bottom of the hind foot and the bottom of the two forks of the forefoot, and anti-slip teeth are provided on the bottom of the support pads.

[0021] The present invention has the following advantages over the prior art:

[0022] This invention provides a bionic foot for robots with a human-like arch structure. The foot is designed with a three-segment structure: front, middle, and rear. The middle segment is movably connected to the bottom of the lower leg rod via an ankle ball joint. A rear elastic support mechanism, rotatably connected to the lower leg rod, provides elastic upward support to the rear foot. A front elastic support mechanism, also rotatably connected to the lower leg rod, provides elastic upward support to the forefoot and controls the opening and closing movements of the two forefoot forks. This increases the degrees of freedom of the bionic foot, making it more flexible. Its built-in elastic structures can store energy and significantly cushion and dampen vibrations, thereby enhancing the stability of the foot support when the robot is upright, walking, and traversing uneven terrain, thus enabling it to adapt to various complex and changing terrains. In addition, the concave sole of the foot forms a longitudinal arch, which reduces the unnecessary contact area between the foot and the ground and supports and protects the bionic foot. The two forefoot forks are connected to the midfoot at their rear ends, and the gap between the two forks forms a concave lateral arch. Combined with the longitudinal arch and the rearfoot, they form a triangular support structure, which can maintain foot stability and distribute gravity, making the robot stand more stably. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention.

[0024] Figure 2 This is a schematic diagram of the structure of the connection between the lower leg bar and the midfoot of the present invention.

[0025] Figure 3 This is a schematic diagram of the front and rear elastic support mechanisms connected to the lower leg rod of the present invention.

[0026] Figure 4 This is a schematic diagram of the foot mechanism of the present invention.

[0027] Figure 5 This is a schematic diagram of the foot mechanism of the present invention from another perspective.

[0028] Numbering in the diagram: 1 Lower leg bar, 2 Foot mechanism, 3 Forefoot, 4 Midfoot, 5 Heel, 6 Ankle ball joint, 7 Ball head, 8 Upper joint cap, 9 Lower joint cap, 10 Fork, 11 Front rotation axis, 12 Front tension spring, 13 Upper elastic support rod, 14 Lower elastic support rod, 15 First rotation axis, 16 Connecting rod, 17 Second rotation axis, 18 Sliding axis, 19 Toe, 20 Fifth rotation axis, 21 Lug, 22 Connecting part, 23 Support spring, 24 Longitudinal arch, 25 Support pad, 26 Anti-slip teeth, 27 Rear rotation axis, 28 Rear tension spring, 29 Rear spring support rod, 30 Third rotation axis, 31 Fourth rotation axis. Detailed Implementation

[0029] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0030] See Figures 1 to 5 This embodiment discloses a robotic bionic foot with a human-like arch structure, including a foot mechanism 2 connected to a lower leg rod 1. The foot mechanism 2 includes a forefoot 3, a midfoot 4, and a rearfoot 5 that are movably connected in sequence. The bottom of the lower leg rod 1 is movably connected to the midfoot 4 of the foot mechanism 2 via an ankle ball joint 6. The ankle ball joint 6 includes a ball head 7, an upper joint cap 8, and a lower joint cap 9. The ball head 7 is connected to the lower leg rod 1 via a threaded structure at its upper end. The spherical surface at the lower end of the ball head 7 fits into the lower joint cap 9. The lower joint cap 9 is integrally formed with the midfoot 4. The upper joint cap 8 is detachably connected to the lower joint cap 9 via screws, confining the ball head 7 within the motion cavity formed by the upper joint cap 8 and the lower joint cap 9, allowing them to rotate within a certain angle.

[0031] The forefoot 3 includes two forks 10 arranged side by side. The rear ends of the two forks 10 are rotatably connected to the front end of the midfoot 4 via a front rotation shaft 11. The axial direction of the front rotation shaft 11 extends vertically. The two forks 10 are elastically connected by a front tension spring 12. The front tension spring 12 is hooked to the two forks 10 by hooks at both ends to limit the lateral opening. The tops of the two forks 10 are connected to the lower leg rod 1 via a front elastic support mechanism. The front elastic support mechanism includes an upper elastic support rod 13 and two lower elastic support rods 14, all of which are spring support rods. The fixed end of the upper elastic support rod 13 is rotatably connected to the middle section of the lower leg rod 1 via a first rotating shaft 15, which extends axially to the left and right. The movable end of the upper elastic support rod 13 is provided with a connecting rod 16 extending axially to the left and right. The fixed ends of the two lower elastic support rods 14 are rotatably connected to the left and right ends of the connecting rods 16 via a second rotating shaft 17, which extends axially to the front and rear. Each of the two forks 10 is provided with a sliding shaft 18, and the movable ends of the two lower elastic support rods 14 are slidably engaged with the sliding shafts 18 of the two forks 10. The movable ends of the two lower elastic support rods 14 drive the two forks 10 of the forefoot 3 to open and close. The sliding shafts 18 are provided with limiting structures at both ends to limit the sliding stroke of the lower elastic support rods 14, thereby controlling the degree to which the left and right forks 10 of the forefoot 3 open along the left and right sides.

[0032] When the robot's bionic foot tilts forward during movement, the front elastic support mechanism is loaded. While supporting the lower leg rod 1 and inhibiting its forward tilting, it transmits force to the two forks 10 of the forefoot 3, causing the two forks 10 of the forefoot 3 to open at a certain angle, thereby providing better support and ensuring more stable contact between the foot and the ground.

[0033] The front ends of the two forks 10 are rotatably connected to toes 19. The rear ends of the toes 19 are rotatably connected to the front ends of the forks 10 through the fifth rotating shaft 20. A torsion spring is provided between the fifth rotating shaft 20 and the mounting hole of the toes 19, so that the toes 19 can rotate around the forks 10 of the forefoot 3 within a certain angle when under load. After the load is removed, the toes 19 can automatically return to their original position.

[0034] In this embodiment, the specific connection structure between the fork 10 and the midfoot 4 is as follows: the rear end of the fork 10 is provided with a lug 21, and the front end of the midfoot 4 is provided with a U-shaped connecting part 22. The lug 21 is embedded in the groove of the connecting part 22 at the front end of the midfoot 4. The front rotating shaft 11 passes through both the connecting part 22 and the lug 21, realizing the rotational connection between the fork 10 and the midfoot 4. An elastic body is provided in the gap between the upper and lower sides of the lug 21 and the connecting part 22 of the midfoot 4, and the elastic body provides elastic support for the upper and lower ends of the lug 21. The elastic body is made of an elastic material, such as a support spring 23. Two support springs 23 are respectively fitted on the upper and lower sections of the front rotating shaft 11, and the two support springs 23 provide elastic pressure support for the upper and lower sides of the lug 21. With the elastic body provided on the upper and lower sides of the lug 21 of the fork 10, when encountering uneven road surfaces, the left and right sides of the fork 10 of the midfoot 3 can be slightly raised to adapt to changes in terrain.

[0035] The midfoot 4 has an upward-curving arch 24 at its bottom. The two forks 10 of the forefoot 3 are connected to the midfoot 4 at their rear ends, forming a concave lateral arch through the gap between the two forks 10. The lateral arch provides support, cushioning, and weight distribution through the elasticity of the connection between the two forks 10 of the forefoot 3 and the midfoot 4. The longitudinal arch 24 and the lateral arch simulate the longitudinal and lateral arches of the human foot, effectively reducing unnecessary contact area between the foot and the ground, thus supporting the foot and distributing weight. Support pads 25 are provided on the bottom of the heel 5 and the bottom of the two forks 10 of the forefoot 3. The bottom of the support pads 25 has anti-slip teeth 26 to prevent slippage and maintain the stability and flexibility of the robot's movement.

[0036] The front end of the heel 5 is rotatably connected to the rear end of the midfoot 4 via a rear rotation shaft 27. The axial direction of the rear rotation shaft 27 extends in the left-right direction. The bottom of the heel 5 is elastically connected to the bottom of the midfoot 4 via a rear tension spring 28. The rear tension spring 28 provides elastic downward pull on the heel 5. The rear tension spring 28 allows the heel 5 to rotate around the midfoot 4 within a certain angle, and it can buffer and dampen vibrations when under load, limiting the range of motion of the heel 5 and allowing the heel 5 to return to its original position after the load is removed. The top of the heel 5 is connected to the lower leg rod 1 via a rear elastic support mechanism. The upper and lower ends of the rear elastic support mechanism are rotatably connected to the middle section of the lower leg rod 1 and the heel 5, respectively, providing elastic upward pull on the heel 5. The rear elastic support mechanism employs a rear spring support rod 29. The fixed end of the rear spring support rod 29 is rotatably connected to the middle section of the lower leg rod 1 via a third rotating shaft 30, and the movable end of the rear spring support rod 29 is rotatably connected to the middle section of the heel 5 via a fourth rotating shaft 31. The axes of the third rotating shaft 30 and the fourth rotating shaft 31 both extend in the left-right direction. The heel 5 has an overall U-shaped structure with an open front end. The two ends of the front end of the heel 5 are rotatably connected to the rear end of the midfoot 4 via a rear rotating shaft 27. The movable end of the rear spring support rod 29 is embedded in the hollow part of the heel 5. This structural design can reduce the weight of the foot and achieve uniform elastic upward pull of the rear spring support rod 29 on the heel 5.

[0037] Each rotating shaft can be constructed using a screw and nut mechanism to achieve a rotating connection between the two components.

[0038] When the robot's bionic foot tilts backward during movement, the rear spring support rod 29 is loaded. While supporting the lower leg rod 1 and inhibiting its backward tilting, it transmits force to the rear foot 5, making the rear foot 5 more stable in contact with the ground. The spring inside the rear spring support rod 29 can play a good role in cushioning and shock absorption when the rear foot 5 contacts the ground.

[0039] When the robot is in a normal standing position, the simultaneous restraint of the front elastic support mechanism and the rear elastic support mechanism ensures that the robot is in a stable standing position.

[0040] When the robot's lower leg rod 1 tilts forward, it compresses the front elastic support mechanism, causing the movable ends of the upper elastic support rod 13 and the two lower elastic support rods 14 to contract. Energy is absorbed and vibration is damped by the springs within the upper elastic support rod 13 and the two lower elastic support rods 14. Simultaneously, the load is transmitted through the upper elastic support rod 13 and the two lower elastic support rods 14 to the two forks 10 of the forefoot 3, causing the left and right forks 10 of the forefoot 3 to open to the left and right at a certain angle. This, combined with the longitudinal arch 24 on the midfoot 4 and the rearfoot 5, forms a stable triangular support structure, supporting the foot and distributing the weight.

[0041] When the robot's lower leg rod 1 tilts backward, it compresses the rear elastic support mechanism, causing the movable end of the rear spring support rod 29 to contract. The spring within the rear spring support rod 29 absorbs energy, providing cushioning and shock absorption. Simultaneously, the load is transmitted to the heel 5 through the rear spring support rod 29, ensuring the front of the heel 5 fits tightly against the rear of the midfoot 4 to suppress backward tilting and maintain foot stability. When the foot lifts during walking, the lower leg rod 1 tilts forward slightly. At this time, the rear spring support rod 29 is stretched, and under the action of the rear tension spring 28, the heel 5 rotates slightly downward around the midfoot 4, preparing for the heel 5 to land, providing cushioning and shock absorption, and better conforming to the human foot's walking posture.

[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A bionic foot for robots with a human-like arch structure, comprising a foot mechanism (2) connected to a lower leg rod (1), characterized in that: The foot mechanism (2) includes a forefoot (3), a midfoot (4) and a heel (5) that are movably connected in sequence. The bottom of the lower leg rod (1) is movably connected to the midfoot (4) of the foot mechanism (2) through the ankle ball joint (6). The front end of the heel (5) is rotatably connected to the rear end of the midfoot (4) via the rear rotation shaft (27). The axis of the rear rotation shaft (27) extends in the left and right direction. The bottom of the heel (5) is elastically connected to the bottom of the midfoot (4) via the rear tension spring (28). The rear tension spring (28) elastically pulls down the heel (5). The top of the heel (5) is connected to the calf rod (1) via the rear elastic support mechanism. The upper and lower ends of the rear elastic support mechanism are rotatably connected to the middle section of the calf rod (1) and the heel (5) respectively. The rear elastic support mechanism elastically pulls up the heel (5). The forefoot (3) includes two forks (10) arranged side by side. The rear ends of the two forks (10) are rotatably connected to the front end of the midfoot (4) via a front rotation shaft (11). The axial direction of the front rotation shaft (11) extends vertically. The two forks (10) are elastically connected by a front tension spring (12). The tops of the two forks (10) are connected to the lower leg rod (1) via a front elastic support mechanism. The front elastic support mechanism includes an upper elastic support rod (13) and two lower elastic support rods (14). The fixed end of the upper elastic support rod (13) is rotatably connected to the middle section of the lower leg rod (1) via a first rotation shaft (15). A rotating shaft (15) extends axially to the left and right. The movable end of the upper elastic support rod (13) is provided with a connecting rod (16) extending to the left and right. The fixed ends of the two lower elastic support rods (14) are respectively connected to the left and right ends of the connecting rod (16) through a second rotating shaft (17). The axial direction of the second rotating shaft (17) extends forward and backward. The two forks (10) are respectively provided with sliding shafts (18). The movable ends of the two lower elastic support rods (14) are respectively slidably engaged with the sliding shafts (18) of the two forks (10). The two forks (10) of the forefoot (3) are driven to open and close through the movable ends of the two lower elastic support rods (14).

2. The bionic foot of a robot with a human-like arch structure as described in claim 1, characterized in that: The midfoot (4) has an upward concave bottom to form a longitudinal arch (24), and the two forelegs (10) of the forefoot (3) are connected to the midfoot (4) at their rear ends, forming an upward concave transverse arch by combining the gap between the two forelegs (10).

3. The bionic foot of a robot with a human-like arch structure as described in claim 1, characterized in that: The fork (10) has a lug (21) at the rear end and a U-shaped connecting part (22) at the front end of the midfoot (4). The lug (21) is embedded in the groove of the connecting part (22) at the front end of the midfoot (4). The front rotating shaft (11) passes through the connecting part (22) and the lug (21) at the same time, realizing the rotational connection between the fork (10) and the midfoot (4). An elastic body is provided in the gap between the upper and lower sides of the lug (21) and the connecting part (22) of the midfoot (4), and the elastic body provides elastic support for the upper and lower ends of the lug (21).

4. The bionic foot of a robot with a human-like arch structure as described in claim 1, characterized in that: In the aforementioned front elastic support mechanism, the upper elastic support rod (13) and the two lower elastic support rods (14) are all spring support rods.

5. The bionic foot of a robot with a human-like arch structure as described in claim 1, characterized in that: The rear elastic support mechanism is a rear spring support rod (29). The fixed end of the rear spring support rod (29) is rotatably connected to the middle section of the lower leg rod (1) through a third rotating shaft (30). The movable end of the rear spring support rod (29) is rotatably connected to the middle section of the heel (5) through a fourth rotating shaft (31). The axial directions of the third rotating shaft (30) and the fourth rotating shaft (31) are both extended in the left and right directions.

6. The bionic foot of a robot with a human-like arch structure as described in claim 5, characterized in that: The rear foot (5) has a U-shaped structure with an open front end. The two ends of the front end of the rear foot (5) are rotatably connected to the rear end of the middle foot (4) through the rear rotation shaft (27). The movable end of the rear spring support rod (29) is embedded in the hollow part of the rear foot (5).

7. The bionic foot of a robot with a human-like arch structure as described in claim 1, characterized in that: The front ends of the two forks (10) are respectively rotatably connected to toes (19), and the rear ends of the toes (19) are rotatably connected to the front ends of the forks (10) through a fifth rotating shaft (20). A torsion spring is provided between the fifth rotating shaft (20) and the mounting hole of the toes (19).

8. The bionic foot of a robot with a human-like arch structure as described in claim 1, characterized in that: The sliding shaft (18) is provided with limiting structures at both ends to limit the sliding stroke of the lower elastic support rod (14).

9. A bionic foot with a human-like arch structure as described in claim 2, characterized in that: The bottom of the heel (5) and the bottom of the two forks (10) of the forefoot (3) are respectively provided with support pads (25), and the bottom of the support pads (25) is provided with anti-slip teeth (26).

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