Humanoid robot bionic foot with autonomous terrain testing capability

Abstract

The invention discloses a humanoid robot bionic foot with autonomous terrain testing capability, which comprises a front sole component and a rear sole component which are flexibly connected through a sole fascia, a support connecting frame is hinged with an arch component to form a space transmission structure, and the support connecting frame and the arch component cooperate with the fascia to form an arched composite support. The locust-imitating foot pad has the innovation points that the locust-imitating foot pad realizes segmented flexible and local fitting buffering; the pelma fascia and the arch-shaped arch absorb impact in the initial gait stage, and rigid body transmission is reduced; the dorsal muscle imitating elastic sheet and the achilles tendon imitating elastic sheet store and release energy in the second half of the gait, and the dynamic stability is improved; pressure sensors are arranged at three points of the front / rear sole and the ankle joint, a space stress model is constructed, distribution of the force center and the touchdown point of the sole is analyzed in real time, and the terrain state is judged. Through structure-sensing coupling, the foot can autonomously judge the terrain under the non-driving state, passive foot landing adaptation is achieved, environment dependence is simplified, and the application range is wide. And the walking robustness under the complex terrain is improved.

Description

Technical Field

[0001] The present invention relates to the field of robots, and in particular to a humanoid robot bionic foot with autonomous terrain testing capability. Background Art

[0002] With the increasing application of humanoid robots in complex terrain inspection, post-disaster rescue, home services and other fields, higher requirements are placed on the adaptability and force perception ability of their foot structure. As the key part of the robot's contact with the ground, its structural performance directly affects the robot's overall stability, gait efficiency and adaptability to the environment.

[0003] Currently, the feet of humanoid robots generally use a rigid frame combined with a rubber cushioning layer and independent sensors to construct a basic grounding structure, and cooperate with a rigidly connected ankle joint drive unit to achieve gait control. For example, existing typical humanoid robots such as ASIMO and Atlas all use a rigid sole combined with an electric drive to achieve stable walking. The purpose of its structure is to provide high support stiffness and controllable landing posture. The main design purpose of this type of foot mechanism is to provide basic support force and cushioning capacity, which requires reliance on complex control algorithms and sensor compensation, and the system consumes high energy. Moreover, due to the rigid plate, the sole of the foot has poor fit with the ground, and generally only a single-point force sensor is set at the ankle, which cannot identify and respond to different contact conditions of the forefoot and forefoot.

[0004] In recent years, to further enhance the biomimetic properties and functional adaptability of foot structures, some research institutions have attempted to design humanoid foot structures with multiple degrees of freedom. For example, these structures incorporate independently driven toe joints or elastic toe and arch structures to impart a degree of active deformation to the foot. These structures aim to enhance plantar contact and dynamic adjustment, partially achieving the foot's nonlinear support characteristics and multi-directional cushioning capabilities. However, these foot designs still present some challenges: 1. The structure is complex and the volume is large, which is not conducive to the miniaturization of the foot; 2. Requires multiple motors or actuators to drive, which is costly, consumes large amounts of power, and compromises reliability and stability. 3. When only the forefoot of the bionic foot is in contact with the ground, the existing arch structure or elastic toe structure will generate a reverse elastic force, inhibiting the forefoot from contacting the ground, preventing the forefoot from fully contacting the ground and reducing stability. 4. The bionic level is limited, lacking multi-level structural collaborative design. It only simulates the foot structure at the macroscopic level and lacks the structural and functional coordination mechanism between key biological tissues such as the arch, fascia, and tendon. 5. The plantar cushioning performance is still limited, there is a lack of distributed sensing means, and the information dimension is insufficient, making it difficult to complete autonomous terrain testing and response.

[0005] In addition, the terrain recognition and force perception systems used on existing bionic feet have obvious shortcomings. Some robotic systems integrate pressure sensors or six-dimensional force / torque sensors in the feet. For example, the MIT Cheetah series uses a single-point six-axis force sensor for gait judgment. This type of system focuses on analyzing the ground state through contact force data, with the goal of achieving rapid recognition of contact modes such as sliding, stepping on air, and landing. However, the sensors of this type of system are concentrated at a single point on the ankle, making it difficult to obtain local force information in the palm area; there is a lack of multi-point force feedback distributed in the sole area, and it is impossible to accurately judge terrain features such as contact area, friction state, and slope direction; the structure and sensor system are separated, and structure-perception coupling is not formed, making it difficult to achieve physical-perception collaborative terrain testing.

[0006] The above shortcomings are mainly due to the fact that existing technologies generally fail to organically combine bionic structures, flexible response mechanisms and distributed sensing systems. Most foot designs are still limited to rigid support and single-point perception, and lack in-depth imitation and engineering implementation of the "spatial structure + flexible response + multi-point contact perception" mechanism of biological feet.

[0007] Therefore, at present, there is still a lack of a humanoid robot foot structure that is relatively simple, flexible and passive, has spatial support and deformation capabilities, and can achieve multi-point force perception and autonomous terrain testing. Summary of the Invention

[0008] The technical problem to be solved by the present invention is that the foot structure of the existing humanoid robot mentioned in the background technology is insufficient in the bionic level, lacks effective modeling and implementation of the complex coupling relationship between biological structures such as the arch of the foot, fascia and tendons, has weak rigid-flexible coupling ability, and lacks flexibility, resulting in difficulty in absorbing the impact of landing. In addition, the perception means are single and the perception range is limited, which restricts the collaborative feedback mechanism of structure and function.

[0009] The existing humanoid robot mentioned in the background art has a strong rigidity in its foot structure and a lack of flexibility, which makes it difficult to absorb the impact of landing. In addition, the sensing means are single, making it difficult to form a coordinated feedback mechanism between structure and function.

[0010] In response to the above technical problems, a humanoid robot bionic foot with autonomous terrain testing capability is proposed; it is achieved through the following technical solutions: a humanoid robot bionic foot with autonomous terrain testing capability, including a forefoot component, a rear foot component, an ankle joint bracket, a front arch component, a rear arch component, a bionic elastic connecting piece and a plantar fascia, the plantar fascia flexibly connects the forefoot component and the rear foot component, a front support connecting frame is provided on the forefoot component, a rear support connecting frame is provided on the rear foot component, the front support connecting frame is hinged to the front arch component, the rear support connecting frame is hinged to the rear arch component, the front arch component and the rear arch component are connected to the ankle joint together The bracket is hinged; the front arch component, the rear arch component and the plantar fascia work together to form an arched composite support structure; pressure sensors are respectively arranged on the front support connecting frame, the rear support connecting frame and the ankle joint bracket, and the pressure sensors collect mechanical information of the forefoot, the rear foot and the ankle joint in real time; the bionic elastic connecting piece connects the front support connecting frame, the rear support connecting frame and the ankle joint bracket to form an arched structure, and the bionic elastic connecting piece is hinged to the front support connecting frame; the forefoot component and the rear foot component also include a locust-like foot pad, which is arranged on the bottom surface of the forefoot component and the rear foot component and contacts the ground. The locust-like foot pad adapts to the shape of the ground and alleviates the landing cushioning of the bionic foot.

[0011] In the preferred embodiment of the technical solution of the present invention, the bionic elastic connecting piece includes a back muscle imitation elastic piece and an Achilles tendon imitation elastic piece. One end of the back muscle imitation elastic piece is hinged to the front support connecting frame, and the other end is connected to the ankle joint bracket. The Achilles tendon imitation elastic piece is respectively connected to the rear support connecting frame and the ankle joint bracket. This arrangement utilizes the back muscle imitation elastic piece and the Achilles tendon imitation elastic piece to simulate the traction of biological tendons on the arch of the foot, thereby enhancing the dynamic support effect of the foot during the gait cycle.

[0012] In the preferred embodiment of the technical solution of the present invention, the back muscle imitation elastic sheet and the Achilles tendon imitation elastic sheet are pre-bent, and the pre-bent back muscle imitation elastic sheet and the Achilles tendon imitation elastic sheet are elastic. The pre-bending setting facilitates the generation of tension when the foot is compressed, thereby improving the dynamic stability and recovery efficiency of the structure. In scenarios where the ground is gently sloping or obstacles are stepped on, it can suppress excessive deformation of the foot and improve the robot's steady-state crossing ability.

[0013] Preferably, the front support connecting frame includes two oppositely distributed rotating shaft mounting frames, and the rotating shaft mounting frames are provided with a first hinge hole and a second hinge hole. The imitation back muscle elastic sheet on the bionic elastic connecting plate is hinged to the first hinge hole to form a forefoot joint, and the forefoot arch assembly and the second hinge hole form a toe joint. Such an arrangement enables the toe joint to generate a certain rotation angle relative to the ground when only the bottom surface of the forefoot assembly of the bionic foot contacts the ground. The forefoot assembly rotates around the toe joint to ensure that the sole of the entire foot fits the ground as much as possible, ensuring that the humanoid robot can achieve the action of the bottom surface of the forefoot assembly stably acting on the ground, imitating the state of human toes pushing off the ground.

[0014] The preferred technical solution of the present invention is that the rear support connecting frame includes a first hinge seat and a first elastic sheet connecting plate, one end of the rear arch assembly is hinged to the first hinge seat, and the other end is hinged to the ankle joint bracket, the Achilles tendon elastic sheet in the bionic elastic connecting sheet is connected to the first elastic sheet connecting plate and the ankle joint bracket, and the rear arch assembly forms a heel joint at the first hinge seat. This arrangement makes it possible that when only the rear sole assembly of the bionic foot contacts the ground, the heel joint has a certain rotation angle relative to the ground. Under the combined action of the ground reaction force and the Achilles tendon elastic sheet, the rear sole assembly rotates around the heel joint by a certain angle, so that the sole of the entire foot is in as close contact with the ground as possible, and can also absorb impact and vibration when the heel touches the ground, thereby achieving a shock-absorbing effect.

[0015] Preferably, the technical solution of the present invention is that the ankle joint support includes a mounting plate, a first hinge frame, a second elastic sheet connecting plate and a third elastic sheet connecting plate, the first hinge frame is arranged on the mounting plate, the front arch assembly and the rear arch assembly are hinged to the ankle joint support through the first hinge frame to form an ankle joint, the second elastic sheet connecting plate and the third elastic sheet connecting plate are arranged on both sides of the mounting plate, and the back muscle elastic sheet and the Achilles tendon elastic sheet in the bionic elastic connecting sheet are respectively connected to the second elastic sheet connecting plate and the third elastic sheet connecting plate. Such an arrangement enables the ankle joint support to form an arched composite support structure through the back muscle elastic sheet, the Achilles tendon elastic sheet, the front arch assembly, the rear arch assembly and the plantar fascia, thereby achieving good longitudinal support and lateral flexible deformation, thereby improving the stability of the bionic foot.

[0016] In the preferred embodiment of the technical solution of the present invention, the forefoot component and the rearfoot component both include a rigid connecting plate and a rigid fixing ring, and the locust-like foot pad is arranged between the rigid connecting plate and the rigid fixing ring. The middle part of the locust-like foot pad passes through the rigid fixing ring to contact the ground, thereby improving the adhesion and buffering ability of the bionic foot to the ground. The setting of the locust-like foot pad enables the bottom surfaces of the forefoot component and the rearfoot component to adaptively fit the ground, adjust the contact area, and enhance the adhesion and buffering performance under different terrains.

[0017] Preferably, the locust-like foot pad includes a liquid sac for cushioning when in contact with the ground. A liquid injection port is provided on the liquid sac, through which liquid can be injected into and discharged from the liquid sac in a controllable manner. The setting of the liquid sac can make the liquid sac adaptively fit the contact surface by adjusting the amount of liquid in the liquid sac, thereby enhancing the contact area between the bottom surface of the locust-like foot pad and the ground, and enhancing the adhesion and cushioning performance under different terrains.

[0018] In the preferred embodiment of the technical solution of the present invention, the plantar fascia is made of a flexible material with good stretching and recovery properties. The plantar fascia absorbs impact when the bionic foot lands and provides rebound force when the bionic foot is lifted. This arrangement enables the plantar fascia and the arched arch to form a spatial flexible structure, which can provide displacement in the initial stage of gait. The plantar fascia can also absorb the impact of landing, reduce the transmission of impact on the sole of the foot, and ensure the stability of the robot's walking.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The technical solution of the present invention introduces a locust-like pad structure. By providing flexible locust-like pads at the contact points between the forefoot and rearfoot assemblies and the ground, and providing a liquid sac structure inside, pressure regulation and adaptive shape deformation are achieved when the sole of the foot touches the ground. This gives the forefoot and rearfoot assemblies segmented flexibility and ground-contact cushioning functions, enabling multi-point contact on complex terrain, with localized and gradual contact increasing the ground contact area. The plantar fascia and the arch of the foot are used to form a spatially flexible-rigid coupling structure. The flexible plantar fascia connects the front and rear foot components. When the upper end of the simulated arch component composed of the front and rear arch components sinks under load, it produces passive stretching, simulating the coordinated stability mechanism and elastic energy storage and release mechanism of the human plantar fascia. This enables the simulated arch component to have energy storage capacity during the compression phase and generate restoring force during the foot lifting phase, improving the robot's gait efficiency and the naturalness of the foot, making it a bionic foot with similar functions to the human foot. The back muscle and Achilles tendon-mimicking elastic sheets are used to store and release energy during the gait cycle, passively participating in deformation and recovery according to the stress state, helping the foot to achieve different stiffness and flexibility adjustments during the support and swing phases, improving gait stability and flexibility. It can also inhibit excessive deformation of the foot in scenarios such as gentle slopes and encountering obstacles, thereby enhancing stable traversal capabilities. The dorsal muscle elastic sheet and the forefoot arch assembly are respectively hinged to the front support connecting frame to form a double-hinged structure. This double-hinged structure enables the forefoot joint and toe joint to generate a certain angle relative to the ground when only the forefoot assembly of the bionic foot contacts the ground, so that the entire forefoot assembly fits the ground as closely as possible. Ultimately, the humanoid robot can achieve the movement of the forefoot assembly stably acting on the ground, thereby improving stability. In addition, a spatial force information model is constructed by using pressure sensors installed at three points: the forefoot component, the rearfoot component, and the ankle joint support. The support force, friction state, and contact posture of different areas of the foot can be obtained in real time. The three-point torque fusion can infer the center of force (COP) and the distribution of the contact point of the plantar, which can be used to determine whether the terrain is flat, inclined, or there are obstacles, realizing the integration of structure-perception-control, and forming a "structure-perception" coupling response mechanism. The mechanism enables the foot to have a certain degree of autonomous judgment and initial adaptability in a non-driven state. In simple and disordered terrain, the robot can achieve passive adaptation to landing without visual prediction, simplifying environmental dependence and improving walking robustness. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A three-dimensional schematic diagram of a humanoid robot bionic foot with autonomous terrain testing capabilities; Figure 2 A bird's-eye view of a humanoid robot's bionic foot with autonomous terrain testing capabilities; Figure 3 A cross-sectional view of the ankle joint support of a humanoid robot bionic foot with autonomous terrain testing capabilities; Figure 4 It is a partial cross-sectional view of the forefoot component; Figure 5 It is a partial cross-sectional view of the rear foot assembly; Figure 6 This is a three-dimensional diagram of the imitation locust foot pad (bottom view); Figure 7 This is a three-dimensional diagram of the imitation locust foot pad (transparent view); Figure 8 It is a three-dimensional schematic diagram of the front support connecting frame; Figure 9 It is a three-dimensional schematic diagram of the rear support connecting frame; Figure 10 It is a three-dimensional schematic diagram of the ankle brace; Figure 11 A three-dimensional diagram of the front arch assembly and the rear arch assembly connected (excluding the connecting shaft); Figure 12 This is a schematic diagram of the rear arch assembly and the rear support connecting frame after they are matched; Figure 13 Exploded view of a humanoid robot bionic foot with autonomous terrain testing capabilities; Explanation of reference numerals: 1-forefoot assembly, 11-rigid connecting plate, 12-rigid fixing ring, 13-locust-like foot pad, 14-liquid sac, 15-liquid injection port, 16-V-shaped groove, 2-rear foot assembly, 3-front support connecting frame, 31-rotating shaft mounting frame, 32-first hinge hole, 33-second hinge hole, 4-rear support connecting frame, 41-first hinge seat, 42-first elastic sheet connecting plate, 5-ankle joint bracket, 51-mounting plate, 52-first hinge frame, 53-second elastic sheet connecting plate Connecting plate, 54-third elastic sheet connecting plate, 55-calf connecting piece, 6-front arch assembly, 61-front arch, 62-second hinge frame, 63-connecting shaft, 64-connecting bearing, 65-third hinge hole, 7-rear arch assembly, 71-rear arch, 72-second hinge seat, 73-third hinge seat, 74-fourth hinge hole, 8-bionic elastic connecting piece, 81-imitation back muscle elastic piece, 82-back muscle connecting piece, 83-imitation Achilles tendon elastic piece, 9-plantar fascia, 10-pressure sensor. DETAILED DESCRIPTION

[0021] The following is a combination of the embodiments of the present invention Figures 1-13 , the technical solutions in the embodiments of the present invention are described in detail.

[0022] like Figure 1 、 Figure 2 and Figure 13 As shown, a humanoid robot bionic foot with autonomous terrain testing capability includes a forefoot component 1, a rear foot component 2, a front support connecting frame 3, a rear support connecting frame 4, an ankle joint support 5, a front arch component 6, a rear arch component 7, a bionic elastic connecting piece 8, a plantar fascia 9 and a pressure sensor 10.

[0023] The front support connecting frame 3 is installed on the upper surface of the forefoot assembly 1, and a pressure sensor 10 for detecting mechanical information at the forefoot is fixed between the front support connecting frame 3 and the forefoot assembly 1. The rear support connecting frame 4 is installed on the upper surface of the rear foot assembly 2, and a pressure sensor 10 for detecting mechanical information at the rear foot is also installed between the rear support connecting frame 4 and the rear foot assembly 2 using screws.

[0024] One end of the front arch assembly 6 is hinged to the front support connecting frame 3, and the other end is hinged to the rear arch assembly 7, wherein the front arch assembly 6 and the front support connecting frame 3 form a toe joint at the hinge, and the other end of the rear arch assembly 7 is hinged to the rear support connecting frame 4 to form a heel joint at the hinge, and can rotate along the hinge.

[0025] The other ends of the front arch assembly 6 and the rear arch assembly 7 are hinged and then hinged to the ankle joint support 5 to form an ankle joint at the hinge, and can rotate along the hinge. In addition, in order to detect the mechanical information at the ankle, a pressure sensor 10 is also installed on the ankle joint support 5 using screws.

[0026] The bionic elastic connecting piece 8 includes a back muscle imitation elastic piece 81 and an Achilles tendon imitation elastic piece 83, wherein one end of the back muscle imitation elastic piece 81 is fixed on the ankle joint bracket 5, and the other end is hinged to the front support connecting frame 3, and forms a forefoot joint at the hinge; one end of the Achilles tendon imitation elastic piece 83 is fixed on the ankle joint bracket 5, and the other end is fixed on the rear support connecting frame 4.

[0027] One end of the plantar fascia 9 is fixed to the forefoot component 1, and the other end is fixed to the rearfoot component 2. The plantar fascia 9, the front arch component 6 and the rear arch component 7 form an arched support structure through the front support connecting frame 3, the rear support connecting frame 4 and the ankle joint support 5, thereby improving the spatial support deformation ability and landing cushioning ability of the bionic foot.

[0028] like Figure 1 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 As shown, the forefoot assembly 1 includes a rigid connecting plate 11 , a rigid fixing ring 12 and a locust-like foot pad 13 , and the locust-like foot pad 13 is clamped between the rigid connecting plate 11 and the rigid fixing ring 12 .

[0029] The rigid connecting piece 11 is a rectangular metal piece with a threaded hole at the edge of the rigid connecting piece 11. The rigid fixing ring 12 is a rectangular ring with an opening in the middle. The outer dimensions of the rigid fixing ring 12 are the same as those of the rigid connecting piece 11. The imitation locust foot pad 13 is placed on the lower surface of the rigid connecting piece 11, and the rigid fixing ring 12 is placed on the imitation locust foot pad 13. The imitation locust foot pad 13 can be clamped and fixed between the rigid connecting piece 11 and the rigid fixing ring 12 by screws.

[0030] The locust-like foot pad 13 is a rectangular pad made of elastic polyurethane material. The overall outer dimensions of the locust-like foot pad 13 are the same as those of the rigid connecting piece 11. When the bionic foot contacts the ground, the bottom of the locust-like foot pad 13 contacts the ground first. In order to improve the adaptability of the locust-like foot pad 13 to the ground and reduce the impact transmission of the rigid foot sole, a hollow sealed chamber is opened inside the locust-like foot pad 13. This chamber is named a liquid sac 14. An injection port 15 connected to the liquid sac 14 is fixed on the upper part of the liquid sac 14. The injection port 15 is a circular plastic tube. The injection port 15 passes through the rigid connecting piece 11. Liquid or gas can be injected into the liquid sac 14 through an external micro-connection pump, thereby realizing the adjustment of the internal pressure of the cavity to adapt to irregular ground.

[0031] In order to increase the friction of the bottom surface of the locust-like foot pad 13, a concave V-shaped groove 16 with a V-arc surface is opened on the bottom surface of the locust-like foot pad 13. The V-shaped groove 16 is used to improve the adaptability to the ground and the friction performance, further improving the stability of the bionic foot during movement.

[0032] In order to improve the adaptability of the simulated locust foot pad 13 to irregular ground, the liquid capsule 14 can be a single-chamber capsule or a multi-chamber capsule. In this embodiment, a single-chamber capsule is preferably used, and a liquid injection port 15 is separately installed in the chamber of the liquid capsule 14. The liquid injection port 15 can be used to inject or discharge liquid into the liquid capsule 14 to adjust the internal pressure of the simulated locust foot pad 13. When the simulated locust foot pad 13 contacts the uneven ground, the simulated locust foot pad 13 automatically adapts to the shape of the ground and changes to adapt to the irregular ground.

[0033] In order to facilitate the locust-like foot pad 13 to adapt to changes in the shape of the ground, a pressure sensor is fixed in the liquid capsule 14 with glue. The pressure sensor can collect the changes in pressure in the liquid capsule 14 when the locust-like foot pad 13 contacts the ground. The pressure sensor is connected to the control system set inside the robot through the liquid injection port 15. The control system adjusts the pressure in the liquid capsule 14 accordingly through the signal received by this pressure sensor to achieve adaptation to the shape of the ground.

[0034] Definition: In this embodiment, with the ground as a reference, when the bionic foot walks on the ground, the direction in which the locust-like foot pad 13 contacts the ground is downward, otherwise it is upward.

[0035] The rear foot component 2 has the same structure as the forefoot component 1, both including the forefoot component 1 including a rigid connecting plate 11, a rigid fixing ring 12 and a locust-like foot pad 13. The locust-like foot pad 13 is clamped between the rigid connecting plate 11 and the rigid fixing ring 12 to achieve cushioning and adaptation to the ground.

[0036] Regarding the automatic adaptation of the locust-like foot pad 13 to the ground, when the bionic foot falls and contacts the ground, the locust-like foot pad 13 refers to the geometry of the locust foot and presents an approximate multi-curvature contact surface. The area outside the V-shaped groove 16 preferentially contacts the ground, forming multiple local contact points. The contact area and degree of deformation depend on the ground shape. When the locust-like foot pad 13 contacts the ground, the pressurized liquid in the cavity will flow, resulting in a slight internal pressure change. This change is fed back to the main control unit inside the robot through the pressure sensor arranged in the liquid capsule 14. The control unit compares the feedback value with the preset target pressure, determines the current hardness or roughness of the ground, actively adjusts the cavity pressure, and controls the micro pump to inject or draw liquid into the liquid capsule 14 from the outside through the liquid injection port 15, thereby achieving automatic adaptation to irregular ground.

[0037] like Figure 4 and Figure 8As shown, the front support connecting frame 3 includes a rectangular mounting plate made of metal, and a threaded hole is opened on the surface of the mounting plate. The front support connecting frame 3 is connected to the rigid connecting plate 11 on the forefoot component 1 through the threaded hole by screws. In order to facilitate the installation of the front arch component 6 and the imitation back muscle elastic sheet 81, two rectangular plates are welded perpendicular to the surface of the mounting plate. This rectangular plate is named the shaft mounting frame 31.

[0038] The two rotating shaft mounting frames 31 are distributed opposite to each other, and two groups of through holes are opened on the rotating shaft mounting frames 31, one group close to the outside is the first hinge hole 32, and the other group is the second hinge hole 33. One end of the imitation back muscle elastic sheet 81 is hinged to the first hinge hole 32 to form a forefoot joint, and one end of the front arch 61 in the front arch assembly 6 is hinged to the second hinge hole 33 to form a toe joint. The imitation back muscle elastic sheet 81 and the front arch 61 can rotate along the hinge.

[0039] In order to realize terrain recognition and feedback adjustment of foot support posture, a pressure sensor 10 is installed between the front support connecting frame 3 and the rigid connecting plate 11 by screws. In addition, a pressure sensor 10 is installed between the mounting plate 51 and the calf connecting member 55 by screws, and a pressure sensor 10 is also installed between the rear support connecting frame 4 and the rigid connecting plate 11 of the rear foot sole assembly 2 by screws. The pressure sensor 10 is an existing six-dimensional force sensor and can be used directly. The pressure sensor 10 can detect the three-dimensional force and three-dimensional torque in the support phase of the robot's forefoot, hindfoot and ankle joints. By collecting the omnidirectional force / torque data of the six-dimensional force sensor when the foot lands, and using the existing three six-dimensional force sensor data fusion and posture solution algorithm, the plantar support force distribution, ground inclination, foot contact area range and posture direction can be calculated in real time. This structural design and force perception scheme can effectively improve the robustness of the bionic foot on irregular terrain and reduce the risk of falling.

[0040] like Figure 5 、 Figure 9 and Figure 12 As shown, the rear support connecting frame 4 includes a circular mounting plate, on the surface of which a rectangular first hinge seat 41 is welded, and a hinge hole is provided on the first hinge seat 41. The rear arch 71 in the rear arch assembly 7 is hinged to the hinge hole by a pin to form a heel joint.

[0041] In order to facilitate the connection between the rear support connecting frame 4 and the rear foot assembly 2, a threaded hole is opened on the circular mounting plate on the rear support connecting frame 4. At the same time, in order to provide feedback support for terrain recognition and posture adjustment, a pressure sensor 10 is also installed between the rear support connecting frame 4 and the rigid connecting plate 11 of the rear foot assembly 2 using screws.

[0042] In order to facilitate the installation of the Achilles tendon-mimicking elastic sheet 83 in the bionic elastic connecting sheet 8, a rectangular connecting plate is welded on the surface of the rear support connecting frame 4. This connecting plate is named the first elastic sheet connecting plate 42. A threaded hole is opened on the first elastic sheet connecting plate 42, and one end of the Achilles tendon-mimicking elastic sheet 83 is fixed to the first elastic sheet connecting plate 42 by a screw.

[0043] like Figure 1 、 Figure 10 and Figure 13 As shown, the ankle joint support 5 includes a mounting plate 51, a first articulated frame 52, a second elastic sheet connecting plate 53, a third elastic sheet connecting plate 54 and a calf connecting member 55, wherein the first articulated frame 52 is welded on the surface of the mounting plate 51, the second elastic sheet connecting plate 53 and the third elastic sheet connecting plate 54 are welded on the side of the mounting plate 51, and the calf connecting member 55 is detachably connected to the mounting plate 51. The calf connecting member 55 can be used to install the entire bionic foot on the calf of the robot. The main function of the calf connecting member 55 is to connect the bionic foot to the calf of the robot. It is an existing device and can be used directly.

[0044] The mounting plate 51 is a rectangular plate with threaded holes on its surface. The first hinged frame 52 is a metal frame with hinge holes for hinged connection with the front arch assembly 6 and the rear arch assembly 7. There are two first hinged frames 52, and the two first hinged frames 52 are spaced apart opposite to each other on the mounting plate 51.

[0045] The second elastic sheet connecting plate 53 and the third elastic sheet connecting plate 54 are rectangular metal sheets. The main function of the second elastic sheet connecting plate 53 and the third elastic sheet connecting plate 54 is to connect with the imitation back muscle elastic sheet 81 and the imitation Achilles tendon elastic sheet 83. Threaded holes are provided on the second elastic sheet connecting plate 53 and the third elastic sheet connecting plate 54. One end of the imitation back muscle elastic sheet 81 is connected to the second elastic sheet connecting plate 53 by screws, and one end of the imitation Achilles tendon elastic sheet 83 is connected to the third elastic sheet connecting plate 54 by screws.

[0046] In order to provide feedback support for terrain recognition and posture adjustment, a pressure sensor 10 is installed between the mounting plate 51 and the calf connector 55 using screws.

[0047] In order to reduce the weight of the bionic foot, in this embodiment, the front support connecting frame 3, the rear support connecting frame 4 and the ankle joint support 5 are all made of high-strength and light-weight aluminum alloy.

[0048] like Figure 1 、 Figure 11 and Figure 13As shown, the front arch assembly 6 includes a front arch 61, and a U-shaped hinge frame is provided at each end of the front arch 61, and this hinge frame is named as the second hinge frame 62. A third hinge hole 65 is provided on the second hinge frame 62. The front arch 61 can be hinged to the rear arch assembly 7 and the second hinge hole 33 on the front support connecting frame 3 using the second hinge frame 62 and the third hinge hole 65 respectively.

[0049] The front arch 61 is made of high-strength and lightweight aluminum alloy. This embodiment preferably uses the existing 6061-T6 aluminum alloy. The cross-section of the front arch 61 is rectangular, and in order to facilitate the formation of an arch support structure with the rear arch assembly 7 and the plantar fascia 9, the front arch 61 is arc-shaped in the length direction, and in order to reduce weight, the middle of the front arch 61 is designed as a weight-reducing hollow structure.

[0050] The rear arch assembly 7 includes a rear arch 71, at one end of which is fixed a U-shaped hinge frame, which is named the third hinge seat 73, and at the other end is provided a rectangular hinge seat, which is named the second hinge seat 72. The rear arch 71 is hinged to the second hinge frame 62 at one end of the front arch 61 through the second hinge seat 72, and the rear arch 71 is hinged to the rear support connecting frame 4 through the third hinge seat 73.

[0051] Regarding the connection between the front arch 61, the rear arch 71 and the ankle joint support 5: The second hinge seat 72 in the posterior arch 71 is inserted into the second hinge frame 62 at one end of the front arch 61, and then placed on the first hinge frame 52 of the ankle joint support 5. Then, a circular connecting shaft 63 is used to pass through the hinge hole on the ankle joint support 5, the third hinge hole 65 on the second hinge frame 62 and the hinge hole on the second hinge seat 72. At this time, the posterior arch 71 and the front arch 61 can rotate around the connecting shaft 63. In order to make the rotation smooth, a flanged connecting bearing 64 is inserted into the hinge hole of the first hinge frame 52. The connecting bearing 64 is fixed to the first hinge frame 52 with screws, and the two ends of the connecting shaft 63 are inserted into the connecting bearing 64 to together constitute an ankle joint.

[0052] The plantar fascia 9 is made of TPU material with high elastic modulus. The plantar fascia 9 is located in the central area of ​​the sole of the foot. The plantar fascia 9 is connected to the forefoot component 1 and the rear foot component 2 by screws. The plantar fascia 9, the front arch 61 and the rear arch 71 together form an arch structure. Because the plantar fascia 9 has good stretching and recovery properties, when the front arch 61 and the rear arch 71 rotate along the hinge during the landing stage of the bionic foot, the plantar fascia 9 absorbs vertical impact and provides lateral flexible recovery force during the support stage, driving the front arch 61 and the rear arch 71 to reset when the bionic foot is lifted.

[0053] like Figure 1 、 Figure 2 、 Figure 3 and Figure 13 As shown, the bionic elastic connecting piece 8 includes a back muscle imitation elastic piece 81 and an Achilles tendon imitation elastic piece 83. The back muscle imitation elastic piece 81 connects the ankle joint support 5 and the front support connecting frame 3, and the Achilles tendon imitation elastic piece 83 connects the ankle joint support 5 and the rear support connecting frame 4.

[0054] The back muscle-imitation elastic sheet 81 and the Achilles tendon-imitation elastic sheet 83 are rectangular sheets, which can be made of metal, rubber, thermoplastic polyurethane or similar materials with a certain elasticity. In this embodiment, 65Mn spring steel sheets are preferably used. The back muscle-imitation elastic sheet 81 is preferably a spring steel sheet with a thickness of 1 mm, and the Achilles tendon-imitation elastic sheet 83 is preferably a spring steel sheet with a thickness of 2 mm. In order to enable the back muscle-imitation elastic sheet 81 and the Achilles tendon-imitation elastic sheet 83 to generate tension when the foot is compressed, the back muscle-imitation elastic sheet 81 and the Achilles tendon-imitation elastic sheet 83 are pre-bent, and the bending of the back muscle-imitation elastic sheet 81 and the Achilles tendon-imitation elastic sheet 83 is pre-loaded during the installation process, so that they have initial deformation in the normal support state, ensuring that the bionic foot can provide rapid response capability at the moment of landing, so that the back muscle-imitation elastic sheet 81 and the Achilles tendon-imitation elastic sheet 83 provide elastic force as the foot deforms dynamically.

[0055] There are two imitation back muscle elastic sheets 81, and the two imitation back muscle elastic sheets 81 are distributed in parallel. In order to facilitate the hinge connection of the imitation back muscle elastic sheet 81 to the first hinge hole 32 on the front support connecting frame 3, a back muscle connecting piece 82 is fixed to one end of the imitation back muscle elastic sheet 81 with a screw. The back muscle connecting piece 82 includes a circular sleeve and a rectangular connecting piece. The connecting piece is connected to the imitation back muscle elastic sheet 81 with a screw. The circular sleeve is sleeved on a mounting pin, and the mounting pin is inserted into the first hinge hole 32.

[0056] Regarding the arrangement of the electrical interface and the adjustment of the liquid in the liquid bag 14 in this embodiment, it is preferred that they are uniformly arranged at the ankle joint support 5, and all sensor signals are uniformly aggregated through a multi-channel signal hub board. This is existing technology and will not be elaborated here.

[0057] The usage process of the bionic foot in this embodiment: When only the bottom surface of the forefoot assembly 1 of the bionic foot contacts the ground, the toe joint has a certain rotation angle relative to the ground. The rotation of the forefoot assembly 1 around the toe joint can make the sole of the bionic foot fit the ground as closely as possible, ensuring that the humanoid robot can realize the action of the forefoot assembly 1 contacting the ground, imitating the state of human toes pushing off the ground. When the sole surface of the foot leaves the ground and is not subjected to any load, the bionic foot will return to its original position under the action of the imitation back muscle elastic sheet 81. When only the rear sole assembly 2 of the bionic foot contacts the ground, the heel joint has a certain rotation angle relative to the ground. Under the combined action of the ground reaction force and the simulated Achilles tendon elastic sheet 83, the rear sole assembly 2 rotates around the joint at a certain angle, so that the sole of the foot is in as close contact with the ground as possible, and can also absorb impact and vibration when the heel touches the ground, thereby achieving a shock-absorbing effect. The simulated Achilles tendon elastic sheet 83 can also restore the sole of the foot and store energy.

[0058] The cushioning process of the bionic foot in this embodiment: When the foot is impacted by the ground, the rear palm assembly is compressed first. Under the combined action of gravity and impact force, the front arch 61 and the rear arch 71 drop down, and the plantar fascia 9 is stretched and elastic, generating elastic force. At this time, the Achilles tendon-like elastic sheet 83 is compressed and elastically deforms to cushion the foot. At the same time, the Achilles tendon-like elastic sheet 83 and the plantar fascia 9 also provide support for subsequent rebound. At the same time, the sac 14 in the locust-like foot pad 13 also provides a certain degree of elasticity, playing a certain cushioning role. When the robot is in a normal standing state, the bottom surfaces of the forefoot assembly 1 and the rear foot assembly 2 contact the ground at the same time. At this time, the bionic elastic connecting piece 8 of the foot pulls the forefoot assembly 1 and the rear foot assembly 2 to provide support for the foot, ensuring stable support of the robot while also limiting the foot posture.

[0059] Regarding restrictions on foot posture: When the bionic robot is in a standing or supporting state, in order to maintain foot stability and prevent excessive deformation or deflection of the foot, certain degrees of freedom need to be passively or semi-actively "constrained". The foot posture restriction here refers to restricting the redundant posture freedom of the foot to enhance rigidity and stability. Specifically, it restricts the excessive pitch deformation between the forefoot component 1 and the rearfoot component 2, which causes the foot to tilt or collapse. Limiting the left and right torsional rotation of the forefoot component 1 and the rearfoot component 2, so that the foot maintains structural symmetry and balanced force under lateral disturbance; Limit the vertical collapse of the arch of the foot, inhibit the arch structure from collapsing and failing due to load, and maintain its arch support shape; When the bionic robot is in a standing or supporting state, the bionic elastic connecting piece 8 is in a stretched state, forming active traction between the forefoot component 1 and the rear foot 2, providing longitudinal support for the foot while passively restricting the excess posture freedom of the foot, ensuring the rigidity and stability of the foot structure in the supporting phase, thereby improving the anti-interference ability and posture robustness of the entire machine during standing and walking.

[0060] The arrangement of the back muscle-imitation elastic sheet 81 and the Achilles tendon-imitation elastic sheet 83 corresponds to the distribution of the back muscles and Achilles tendon in human anatomy, and plays a supporting and traction role when the robot lands and takes off from the ground. In addition, the back muscle-imitation elastic sheet 81 and the Achilles tendon-imitation elastic sheet 83 have certain nonlinear stiffness characteristics. The support stiffness can be adjusted by changing the angle or material parameters, simulating the physiological process of gradual loading and release of real tendons. The back muscle-imitation elastic sheet 81 provides tensile tension during the gait swing phase, and the Achilles tendon-imitation elastic sheet 83 is used to support the load rebound after the heel contacts the ground, allowing the user to dynamically adjust the foot support stiffness according to the robot's gait, load or terrain conditions, thereby improving ground adaptability.

[0061] Regarding the adjustment of the foot support stiffness: the imitation back muscle elastic sheet 81 and the imitation Achilles tendon elastic sheet 83 are respectively arranged at the corresponding positions of the back and Achilles tendon of the foot structure, and have nonlinear elastic characteristics. Users can replace the imitation back muscle elastic sheet 81 and the imitation Achilles tendon elastic sheet 83 of different specifications, adjust their installation angles or actively control them through parallel micro-drive components to achieve dynamic adjustment of the longitudinal stiffness of the foot structure. The angle adjustment of the imitation back muscle elastic sheet 81 and the imitation Achilles tendon elastic sheet 83 and the micro-drive components are existing devices that can be used directly. In this implementation, it is preferred not to use the micro-drive components.

[0062] The technical solution of this embodiment provides locust-like pads 13 at the contact points between the forefoot assembly 1 and the rear foot assembly 2 and the ground, so that the forefoot assembly 1 and the rear foot assembly 2 have segmented flexibility and ground-contacting cushioning functions, allowing them to gradually conform to complex terrain. The plantar fascia 9 and the arch of the foot form a spatially flexible structure, which can provide compression displacement in the initial stage of gait, absorb the impact of landing and reduce the impact transmission of the rigid sole of the foot; The back muscle-mimicking elastic sheet 81 and the Achilles tendon-mimicking elastic sheet 83 are used to store and release energy during the gait cycle, providing additional rebound drive in the second half of the gait. This improves the dynamic stability and recovery efficiency of the structure. On gently sloping surfaces or in situations where obstacles are stepped on, it can effectively suppress excessive deformation of the foot, improving the robot's steady-state traversal capability. This solves the problem of existing humanoid robots' strong foot structure and lack of flexibility, which makes it difficult to absorb landing impact. In addition, pressure sensors 10 arranged at three points, namely the forefoot component 1, the rearfoot component 2 and the ankle joint support 5, are used to construct a spatial force information model, which can obtain the support force, friction state and contact posture of different areas of the foot in real time; the three-point torque fusion can calculate the plantar force center (COP) and the contact point distribution, which can be used to judge whether the terrain is flat, inclined or there are obstacles, realize the integration of structure-perception-control, and form a "structure-perception" coupling response mechanism so that the foot has a certain degree of autonomous judgment and preliminary adaptability in the undriven state. In simple and disordered terrain, the robot can achieve passive adaptation to landing without visual prediction, simplify environmental dependence, improve walking robustness, and solve the problem that the existing humanoid robots have a single perception means and it is difficult to form a structure and function collaborative feedback mechanism.

[0063] The above embodiments are only for illustrating the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the present invention.

Claims

1. A humanoid robot bionic foot capable of autonomous terrain testing, characterized by: The invention comprises a forefoot component (1), a rear foot component (2), an ankle joint support (5), a front arch component (6), a rear foot arch component (7), a bionic elastic connecting piece (8) and a plantar fascia (9), wherein the plantar fascia (9) flexibly connects the forefoot component (1) and the rear foot component (2), a front support connecting frame (3) is provided on the forefoot component (1), a rear support connecting frame (4) is provided on the rear foot component (2), the front support connecting frame (3) is hingedly connected to the forefoot arch component (6), and the rear foot arch component (7) is hingedly connected to the plantar fascia (9). The support connecting frame (4) is hinged with a rear arch assembly (7), and the front arch assembly (6) and the rear arch assembly (7) are hinged with the ankle joint bracket (5); the front arch assembly (6), the rear arch assembly (7) and the plantar fascia (9) cooperate to form an arch composite support structure; pressure sensors (10) are respectively provided on the front support connecting frame (3), the rear support connecting frame (4) and the ankle joint bracket (5), and the pressure sensors (10) collect mechanical information of the forefoot, the rear foot and the ankle joint in real time; The bionic elastic connecting piece (8) connects the front supporting connecting frame (3), the rear supporting connecting frame (4) and the ankle joint support (5) to form an arch structure, and the bionic elastic connecting piece (8) is hinged to the front supporting connecting frame (3); The forefoot component (1) and the rear foot component (2) further include a locust-like foot pad (13). The locust-like foot pad (13) is arranged on the bottom surface of the forefoot component (1) and the rear foot component (2) and contacts the ground. The locust-like foot pad (13) adapts to the shape of the ground and alleviates the landing cushioning of the bionic foot.

2. The humanoid robot bionic foot with autonomous terrain testing capability according to claim 1, characterized in that: The bionic elastic connecting piece (8) comprises a back muscle imitation elastic piece (81) and an Achilles tendon imitation elastic piece (83). One end of the back muscle imitation elastic piece (81) is hinged to the front support connecting frame (3), and the other end is connected to the ankle joint bracket (5). The Achilles tendon imitation elastic piece (83) is respectively connected to the rear support connecting frame (4) and the ankle joint bracket (5).

3. The humanoid robot bionic foot with autonomous terrain testing capability according to claim 2, characterized in that: The back muscle imitation elastic sheet (81) and the Achilles tendon imitation elastic sheet (83) are pre-bent, and the pre-bent back muscle imitation elastic sheet (81) and the Achilles tendon imitation elastic sheet (83) have elasticity.

4. The humanoid robot bionic foot with autonomous terrain testing capability according to claim 1, characterized in that: The front support connecting frame (3) includes two oppositely distributed rotating shaft mounting frames (31), the rotating shaft mounting frames (31) are provided with a first hinge hole (32) and a second hinge hole (33), the back muscle elastic sheet (81) on the bionic elastic connecting sheet (8) is hinged to the first hinge hole (32) to form a forefoot joint, and the front arch assembly (6) and the second hinge hole (33) form a toe joint.

5. The humanoid robot bionic foot with autonomous terrain testing capability according to claim 1, characterized in that: The rear support connecting frame (4) includes a first hinge seat (41) and a first elastic sheet connecting plate (42); one end of the rear arch component (7) is hinged to the first hinge seat (41) and the other end is hinged to the ankle joint bracket (5); the Achilles tendon-mimicking elastic sheet (83) in the bionic elastic connecting sheet (8) is connected to the first elastic sheet connecting plate (42) and the ankle joint bracket (5); and the rear arch component (7) forms a heel joint at the first hinge seat (41).

6. The humanoid robot bionic foot with autonomous terrain testing capability according to claim 2, characterized in that: The ankle joint support (5) comprises a mounting plate (51), a first hinge frame (52), a second elastic sheet connecting plate (53) and a third elastic sheet connecting plate (54), wherein the first hinge frame (52) is arranged on the mounting plate (51), the front arch assembly (6) and the rear arch assembly (7) are hingedly connected to the ankle joint support (5) via the first hinge frame (52) to form an ankle joint, the second elastic sheet connecting plate (53) and the third elastic sheet connecting plate (54) are arranged on both sides of the mounting plate (51), and the back muscle imitation elastic sheet (81) and the Achilles tendon imitation elastic sheet (83) in the bionic elastic connecting plate (8) are connected to the second elastic sheet connecting plate (53) and the third elastic sheet connecting plate (54) respectively.

7. The humanoid robot bionic foot with autonomous terrain testing capability according to claim 1, characterized in that: The forefoot component (1) and the rearfoot component (2) both include a rigid connecting piece (11) and a rigid fixing ring (12); the locust-like foot pad (13) is arranged between the rigid connecting piece (11) and the rigid fixing ring (12); the middle portion of the locust-like foot pad (13) passes through the rigid fixing ring (12) and contacts the ground, thereby improving the adhesion and buffering capabilities of the bionic foot to the ground.

8. The humanoid robot bionic foot with autonomous terrain testing capability according to claim 7, characterized in that: The locust-like foot pad (13) comprises a liquid sac (14) for cushioning when in contact with the ground. The liquid sac (14) is provided with a liquid injection port (15), and liquid can be controlled to be injected into and discharged from the liquid sac (14) through the liquid injection port (15).

9. The humanoid robot bionic foot with autonomous terrain testing capability according to claim 1, characterized in that: The plantar fascia (9) is made of a flexible material with good stretching and recovery properties. The plantar fascia (9) absorbs shock when the bionic foot lands and provides rebound force when the bionic foot is lifted.

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