Biped robot with autonomous terrain testing capability

Abstract

The application discloses a humanoid robot bionic foot with autonomous terrain testing capability, which comprises a forefoot sole assembly and a hindfoot sole assembly flexibly connected through a sole fascia, a support connecting frame and an arch assembly hinged to form a spatial transmission structure, and an arch-shaped composite support formed by the sole fascia and the arch assembly. The application has the following innovative points: segmented flexibility and local adhesion buffering of the locust bionic foot pad; impact absorption by the sole fascia and the arch-shaped arch in the initial stage of gait, and reduction of rigid body transmission; energy storage and release by the biceps lumborum elastic sheet and the Achilles tendon elastic sheet in the second half of the gait, and improvement of dynamic stability; three-point arrangement of pressure sensors on the forefoot sole, the hindfoot sole and the ankle joint, construction of a spatial stress model, real-time analysis of the sole force center and the touch point distribution, and judgment of the terrain state. The application realizes passive adaptation of foot landing, simplifies the environmental dependence, and improves the walking robustness under complex terrain through the coupling of "structure-sensing".

Description

TECHNICAL FIELD

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

[0002] With the increasing application of humanoid robots in complex terrain inspection, post-disaster rescue, home service and other fields, higher requirements are put forward for the adaptability and force perception capability of the foot structure of the robots. As the key part of the robots in contact with the ground, the structural performance of the foot directly affects the stability, gait efficiency and adaptability to the environment of the whole robot.

[0003] Currently, the foot of the humanoid robot is generally constructed by a rigid frame combined with a rubber buffer layer, an independent sensor and the like to realize gait control in cooperation with a rigidly connected ankle joint driving unit. For example, the existing typical humanoid robots such as ASIMO and Atlas complete stable walking by means of a rigid foot bottom and an electric driving mode. The structure aims to provide a relatively high support stiffness and a controllable landing posture. The main design purpose of this kind of foot mechanism is to provide basic support force and buffering capacity, which needs to rely on complex control algorithms and sensor compensation, and the system has high energy consumption. Moreover, due to the rigid plate, the foot bottom has poor adhesion to the ground, and generally a single-point force sensor is arranged at the ankle, which cannot recognize and respond to different contact conditions of the front and rear palms.

[0004] In recent years, in order to further improve the bionics and functional adaptability of the foot structure, some research institutions have attempted to design a humanoid foot structure with multiple degrees of freedom. For example, independent driving toe joints or elastic toes, arch structures and other bionic structures are introduced to enable the foot to have certain active deformation capability. This kind of structure aims to improve the foot bottom adhesion and dynamic adjustment capability, and partially realizes the nonlinear support characteristics and multidirectional buffering capability of the foot. However, this type of foot still has some problems:

[0005] 1. Complex structure and large volume, which is not conducive to the miniaturization of the foot;

[0006] 2. Multiple motors or actuators are needed for driving, which has high cost, large power consumption, and damaged reliability and stability;

[0007] 3. When the bionic foot is only in contact with the ground by the forefoot, the existing arch structure or elastic toe structure will generate a reverse elastic force, which will inhibit the contact between the forefoot and the ground, so that the forefoot cannot be fully adhered to the ground, resulting in reduced stability;

[0008] 4. Limited bionics level, lack of multi-level structure collaborative design, only simulating the foot structure in macroscopic form, lacking the structural and functional collaborative mechanism of arch-fascia-tendon and other key biological tissues;

[0009] 5. The plantar cushioning performance is still limited, there is a lack of distributed sensing methods, and the information dimensions are insufficient, making it difficult to complete autonomous terrain testing and response.

[0010] Furthermore, existing terrain recognition and force sensing systems used on bionic feet have significant drawbacks. Some robotic systems integrate pressure sensors or six-dimensional force / torque sensors in the foot, such as the MIT Cheetah series which uses a single-point six-axis force sensor for gait assessment. These systems focus on analyzing ground conditions through contact force data, aiming to quickly identify contact patterns such as sliding, slipping, and landing. However, the sensors in these systems are concentrated at a single point on the ankle, making it difficult to obtain local force information in the palm area. They also lack multi-point force feedback distributed across the sole area, making it impossible to accurately determine terrain features such as contact area, friction state, and slope direction. Additionally, the structure and sensor system are separated, failing to form a structure-perception coupling, making it difficult to achieve physical-perception coordinated terrain testing.

[0011] The above shortcomings mainly stem from the fact that existing technologies generally fail to organically combine biomimetic structures, flexible response mechanisms, and distributed sensing systems. Most foot designs are still limited to rigid support and single-point sensing, lacking in-depth imitation and engineering implementation of the biological foot's "spatial structure + flexible response + multi-point contact sensing" mechanism.

[0012] Therefore, at present, there is a lack of a humanoid robot foot structure that is relatively simple, compliant and passive, has spatial support deformation capability, and can realize multi-point force perception and autonomous terrain testing. Summary of the Invention

[0013] The technical problem to be solved by this invention is that the existing humanoid robots mentioned in the background art have insufficient biomimetic layers in their foot structure, lack effective modeling and implementation of the complex coupling relationship between biological structures such as the arch, fascia and tendons, weak rigid-flexible coupling ability, lack of flexibility leading to difficulty in absorbing impact upon landing, and single sensing means with limited sensing range, which restricts the collaborative feedback mechanism between structure and function.

[0014] The background technology mentions that existing humanoid robots have rigid foot structures that lack flexibility, making it difficult to absorb impacts upon landing, and that their sensing methods are limited, making it difficult to form a coordinated feedback mechanism between structure and function.

[0015] In view of the above technical problems, the application provides a humanoid robot bionic foot with autonomous terrain testing capability; and the application is realized through the following technical scheme: a humanoid robot bionic foot with autonomous terrain testing capability, comprising a forefoot sole assembly, a hindfoot sole assembly, an ankle joint support, a forefoot arch assembly, a hindfoot arch assembly, a bionic elastic connecting piece and a plantar fascia, the plantar fascia flexibly connecting the forefoot sole assembly and the hindfoot sole assembly, the forefoot sole assembly being provided with a front support connecting frame, the hindfoot sole assembly being provided with a rear support connecting frame, the front support connecting frame being hinged with the forefoot arch assembly, the rear support connecting frame being hinged with the hindfoot arch assembly, the forefoot arch assembly and the hindfoot arch assembly being hinged with the ankle joint support together; the forefoot arch assembly, the hindfoot arch assembly and the plantar fascia cooperatively form an arched composite support structure; pressure sensors are arranged on the front support connecting frame, the rear support connecting frame and the ankle joint support respectively, and the pressure sensors collect mechanical information at the forefoot sole, the hindfoot sole 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 support to form an arched structure, and the bionic elastic connecting piece is hinged with the front support connecting frame; the forefoot sole assembly and the hindfoot sole assembly further comprise locust-like foot pads, the locust-like foot pads being arranged on the bottom surfaces of the forefoot sole assembly and the hindfoot sole assembly and being in contact with the ground, the locust-like foot pads adapting to the shape of the ground and relieving the landing buffer of the bionic foot.

[0016] Preferably, the bionic elastic connecting piece comprises a bionic back muscle elastic piece and a bionic Achilles tendon elastic piece, one end of the bionic back muscle elastic piece is hinged with the front support connecting frame, the other end of the bionic back muscle elastic piece is connected with the ankle joint support, and the bionic Achilles tendon elastic piece is connected with the rear support connecting frame and the ankle joint support respectively; in this way, the bionic back muscle elastic piece and the bionic Achilles tendon elastic piece simulate the traction of biological tendons on the arch, thereby enhancing the dynamic support of the foot in the gait cycle.

[0017] Preferably, the bionic back muscle elastic piece and the bionic Achilles tendon elastic piece are pre-bent, and the pre-bent bionic back muscle elastic piece and the pre-bent bionic Achilles tendon elastic piece have elasticity; the pre-bent setting facilitates the generation of tension when the foot is compressed, thereby improving the dynamic stability and recovery efficiency of the structure, and in the scene of stepping on a gentle slope or an obstacle, the excessive deformation of the foot can be inhibited, and the steady-state crossing ability of the robot is improved.

[0018] Preferably, the front support connecting frame comprises two opposite distribution pivot mounting frames, the pivot mounting frames are provided with first hinge holes and second hinge holes, the bionic back muscle elastic piece on the bionic elastic connecting piece is hinged with the first hinge holes to form a forefoot joint, and the forefoot arch assembly is hinged with the second hinge holes to form a toe joint; in this way, when only the bottom surface of the forefoot sole assembly of the bionic foot is in contact with the ground, the toe joint can produce a certain angle relative to the ground, the forefoot sole assembly rotates around the toe joint to ensure that the sole of the entire foot is as close to the ground as possible, and the humanoid robot can realize the action of stably acting on the ground with the bottom surface of the forefoot sole assembly, thereby simulating the state of human toe stepping on the ground.

[0019] In the preferred technical solution of the present application, the rear support connecting frame comprises a first hinged seat and a first elastic sheet connecting plate, one end of the rear arch assembly is connected with the first hinged seat, and the other end is hinged with the ankle joint support, the Achilles tendon elastic sheet in the bionic elastic connecting sheet is connected with the first elastic sheet connecting plate and the ankle joint support, and the rear arch assembly forms a heel joint at the first hinged seat. Such arrangement makes the heel joint have a certain angle relative to the ground when the bionic foot only contacts the ground with the rear forefoot assembly, and the forefoot assembly rotates a certain angle around the heel joint under the combined action of the ground reaction force and the Achilles tendon elastic sheet, so that the entire foot can be as close as possible to the ground, and can also absorb impact and vibration when the heel contacts the ground, thereby achieving the effect of shock absorption.

[0020] In the preferred technical solution of the present application, the ankle joint support comprises a mounting plate, a first hinged frame, a second elastic sheet connecting plate and a third elastic sheet connecting plate, the first hinged frame is arranged on the mounting plate, the forefoot arch assembly and the rear foot arch assembly are hinged with the ankle joint support through the first hinged 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, the back muscle elastic sheet and the Achilles tendon elastic sheet in the bionic elastic connecting sheet are connected with the second elastic sheet connecting plate and the third elastic sheet connecting plate respectively. Such arrangement makes the ankle joint support form an arch-shaped composite support structure through the back muscle elastic sheet, the Achilles tendon elastic sheet, the forefoot arch assembly, the rear foot arch assembly and the plantar fascia, so as to realize good longitudinal support and transverse flexible deformation, and improve the stability of the bionic foot.

[0021] In the preferred technical solution of the present application, the forefoot assembly and the rear foot assembly each comprise a rigid connecting sheet and a rigid fixing ring, the bionic locust foot pad is arranged between the rigid connecting sheet and the rigid fixing ring, the middle part of the bionic locust foot pad passes through the rigid fixing ring to contact the ground, so as to improve the adhesion and buffering capacity of the bionic foot to the ground. The arrangement of the bionic locust foot pad enables the bottom surface of the forefoot assembly and the rear foot assembly to adaptively fit the ground, adjust the contact area, and enhance the adhesion and buffering performance in different terrains.

[0022] In the preferred technical solution of the present application, the bionic locust foot pad comprises a liquid bag for buffering when contacting the ground, and the liquid bag is provided with a liquid injection port. Liquid can be controllably injected into the liquid bag and discharged from the liquid bag through the liquid injection port. The arrangement of the liquid bag enables the liquid bag to adaptively fit the contact surface by adjusting the amount of liquid in the liquid bag, so as to increase the contact area between the bottom surface of the bionic locust foot pad and the ground, and enhance the adhesion and buffering performance in different terrains.

[0023] The bottom muscle membrane is made of flexible material with good tensile and recovery performance, the bottom muscle membrane absorbs impact when the bionic foot lands, and provides resilience when the bionic foot lifts, such a setting makes the bottom muscle membrane and the arch foot arch form a spatial flexible structure, which can provide displacement in the initial stage of gait, and the bottom muscle membrane can also absorb the impact of landing, reduce the impact transmission of the foot bottom, and ensure the stability of the robot walking.

[0024] Compared with the prior art, the present application has the beneficial effects that:

[0025] The technical scheme of the present application introduces the structure of the locust foot pad, sets flexible locust foot pads at the contact positions of the forefoot palm assembly and the rear foot palm assembly with the ground and internally sets liquid capsule structures, realizes pressure regulation and shape adaptive deformation when the foot bottom touches the ground, makes the forefoot palm assembly and the rear foot palm assembly have segmented flexibility and ground-adhesion buffering function, can realize multi-point contact on complex terrain, and locally gradually adhere to increase the ground contact area;

[0026] The flexible bottom muscle membrane connects the forefoot palm assembly and the rear foot palm assembly, passively stretches during the sinking process of the upper end of the bionic foot arch piece under the load, simulates the cooperative stability mechanism and elastic energy storage and release mechanism of the human foot bottom muscle membrane, makes the bionic foot arch piece have energy storage capacity in the compression stage, generates restoring force in the lifting stage, improves the gait efficiency of the robot and the naturalness of the foot, and makes the bionic foot realize the function similar to the human foot;

[0027] The bionic back muscle elastic sheet and the bionic Achilles tendon elastic sheet participate in energy storage and release in the gait cycle, passively participate in deformation and recovery according to the stress state, assist the foot to realize the adjustment of different stiffness and flexibility in the support and swing stages, improve the stability and flexibility of the gait, and also can inhibit the excessive deformation of the foot in the scenes such as gentle slope and obstacle contact, and improve the stable crossing ability;

[0028] The bionic back muscle elastic sheet and the forefoot arch assembly are respectively hinged with the front support connecting frame to form a double-hinged structure, the double-hinged structure makes the forefoot joint and the toe joint of the bionic foot be able to produce a certain rotation angle relative to the ground when only the forefoot palm assembly of the bionic foot contacts the ground, makes the whole forefoot palm assembly as much as possible adhere to the ground, and finally makes the humanoid robot be able to realize the action of the stable forefoot palm assembly on the ground, and improves the stability;

[0029] In addition, a spatial force information model is constructed by using pressure sensors arranged at three points of the forefoot assembly, the rear foot assembly and the ankle support, so that the support force, the friction state and the contact posture of different areas of the foot can be obtained in real time; three-point torque fusion can calculate the center of pressure (COP) and the contact point distribution of the foot, so as to determine whether the local terrain is flat, inclined or has obstacles, realize the integration of structure-sensing-control, form a "structure-sensing" coupling response mechanism, and enable the foot to have certain autonomous judgment and preliminary adaptation ability in the state of no driving, so that the robot can realize passive adaptation landing without visual prediction in simple and disordered terrain, simplify the environment dependence, and improve the walking robustness. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 A three-dimensional view of a bionic foot of a humanoid robot with autonomous terrain testing capability;

[0031] Figure 2 A top view of a bionic foot of a humanoid robot with autonomous terrain testing capability;

[0032] Figure 3 A cross-sectional view of a bionic foot of a humanoid robot with autonomous terrain testing capability at the ankle support;

[0033] Figure 4 A partial cross-sectional view of a forefoot assembly;

[0034] Figure 5 A partial cross-sectional view of a rear foot assembly;

[0035] Figure 6 A three-dimensional view of a locust foot pad (bottom surface direction);

[0036] Figure 7 A three-dimensional view of a locust foot pad (transparent view);

[0037] Figure 8 A three-dimensional view of a front support connecting frame;

[0038] Figure 9 A three-dimensional view of a rear support connecting frame;

[0039] Figure 10 A three-dimensional view of an ankle support;

[0040] Figure 11 A three-dimensional view of a connection between a front foot arch assembly and a rear foot arch assembly (without connecting shaft);

[0041] Figure 12 A three-dimensional view of a cooperation between a rear foot arch assembly and a rear support connecting frame;

[0042] Figure 13Exploded view of a bionic foot of a humanoid robot with autonomous terrain testing capability

[0043] BRIEF DESCRIPTION OF DRAWINGS 1-forefoot assembly, 11-rigid connecting piece, 12-rigid fixing ring, 13-bionic locust foot pad, 14-liquid capsule, 15-liquid injection port, 16-V-shaped groove, 2-hindfoot assembly, 3-fore support connecting frame, 31-rotating shaft mounting frame, 32-first hinged hole, 33-second hinged hole, 4-hind support connecting frame, 41-first hinged seat, 42-first elastic piece connecting plate, 5-ankle joint support, 51-mounting plate, 52-first hinged frame, 53-second elastic piece connecting plate, 54-third elastic piece connecting plate, 55-calf connecting piece, 6-forefoot arch assembly, 61-forefoot arch, 62-second hinged frame, 63-connecting rotating shaft, 64-connecting bearing, 65-third hinged hole, 7-hindfoot arch assembly, 71-hindfoot arch, 72-second hinged seat, 73-third hinged seat, 74-fourth hinged hole, 8-bionic elastic connecting piece, 81-bionic back muscle elastic piece, 82-back muscle connecting piece, 83-bionic Achilles tendon elastic piece, 9-plantar fascia, 10-pressure sensor. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings. Figures 1-13 The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

[0045] As shown in Figs. 1-3, Figure 1 , Figure 2 and Figure 13 , a bionic foot of a humanoid robot with autonomous terrain testing capability comprises a forefoot assembly 1, a hindfoot assembly 2, a fore support connecting frame 3, a hind support connecting frame 4, an ankle joint support 5, a forefoot arch assembly 6, a hindfoot arch assembly 7, a bionic elastic connecting piece 8, a plantar fascia 9 and a pressure sensor 10.

[0046] The fore support connecting frame 3 is mounted on the upper surface of the forefoot assembly 1, and a pressure sensor 10 for detecting the mechanical information at the forefoot is fixed between the fore support connecting frame 3 and the forefoot assembly 1. The hind support connecting frame 4 is mounted on the upper surface of the hindfoot assembly 2, and a pressure sensor 10 for detecting the mechanical information at the hindfoot is also mounted between the hind support connecting frame 4 and the hindfoot assembly 2 by means of screws.

[0047] The forefoot arch assembly 6 is hinged at one end to the fore support connecting frame 3 and at the other end to the hindfoot arch assembly 7. The forefoot arch assembly 6 and the fore support connecting frame 3 form a toe joint at the hinged position, and the other end of the hindfoot arch assembly 7 is hinged to the hind support connecting frame 4 to form a heel joint at the hinged position, and can rotate along the hinged position.

[0048] The other end of the forefoot arch assembly 6 and the rearfoot arch assembly 7 is hinged and connected with the ankle joint support 5 to form an ankle joint and rotate along the hinge, and a pressure sensor 10 is also installed on the ankle joint support 5 by means of screws to detect the mechanical information at the ankle joint.

[0049] The bionic elastic connecting piece 8 includes a bionic back muscle elastic piece 81 and a bionic Achilles tendon elastic piece 83, wherein the bionic back muscle elastic piece 81 is fixed at one end on the ankle joint support 5 and hinged at the other end with the front support connecting frame 3 to form a forefoot joint at the hinge, and the bionic Achilles tendon elastic piece 83 is fixed at one end on the ankle joint support 5 and at the other end on the rear support connecting frame 4.

[0050] The plantar fascia 9 is fixed at one end on the forefoot assembly 1 and at the other end on the rearfoot assembly 2, and the plantar fascia 9, together with the forefoot arch assembly 6 and the rearfoot arch assembly 7, forms 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 capability and the landing cushioning capability of the bionic foot.

[0051] As shown in Figure 1 , Figure 4 , Figure 5 , Figure 6 and Figure 7 , the forefoot assembly 1 includes a rigid connecting piece 11, a rigid fixed ring 12 and a bionic locust foot pad 13, and the bionic locust foot pad 13 is clamped between the rigid connecting piece 11 and the rigid fixed ring 12.

[0052] The rigid connecting piece 11 is a rectangular metal sheet with threaded holes opened at the edges thereof, the rigid fixed ring 12 is a rectangular ring with an opening in the middle, the outer dimensions of the rigid fixed ring 12 are the same as those of the rigid connecting piece 11, the bionic locust foot pad 13 is placed on the lower surface of the rigid connecting piece 11, the rigid fixed ring 12 is placed on the bionic locust foot pad 13, and the bionic locust foot pad 13 is clamped and fixed between the rigid connecting piece 11 and the rigid fixed ring 12 by means of screws.

[0053] The bionic locust foot pad 13 is a rectangular pad made of elastic polyurethane material, and the overall outer dimensions of the bionic locust foot pad 13 are the same as those of the rigid connecting piece 11. When the bionic foot contacts the ground, the lower part of the bionic locust foot pad 13 contacts the ground first. In order to improve the adaptability of the bionic locust foot pad 13 to the ground and reduce the impact transmission of the rigid foot bottom, a hollow sealed chamber is opened in the bionic locust foot pad 13, which is named as a liquid capsule 14. An injection port 15 which communicates with the liquid capsule 14 is integrally fixed on the upper part of the liquid capsule 14. The injection port 15 is a circular plastic tube which penetrates through the rigid connecting piece 11. A micro connecting pump outside can inject liquid or gas into the liquid capsule 14, so as to adjust the pressure inside the chamber to adapt to irregular ground.

[0054] In order to improve the friction of the bottom surface of the locust foot pad 13, a V-shaped groove 16 is formed on the bottom surface of the locust foot pad 13, which is concave and has a V-shaped arc surface. The V-shaped groove 16 improves the ground adaptability and friction performance, and further improves the stability of the bionic foot movement.

[0055] In order to improve the adaptability of the locust foot pad 13 to the irregular ground, the liquid bag 14 can be a single-chamber bag or a multi-chamber bag. In this embodiment, a single-chamber bag is preferred, and a liquid injection port 15 is arranged in each chamber of the liquid bag 14. The liquid injection port 15 can be used to inject or discharge liquid into the liquid bag 14, so as to adjust the internal pressure of the locust foot pad 13. When the locust foot pad 13 contacts the uneven ground, the locust foot pad 13 automatically adapts to the ground shape and changes, thereby achieving the adaptability to the irregular ground.

[0056] In order to facilitate the locust foot pad 13 to adapt to the change of the ground shape, a pressure sensor is fixed in the liquid bag 14 by using glue. The pressure sensor can collect the change of the pressure in the liquid bag 14 when the locust foot pad 13 contacts the ground. The pressure sensor penetrates through the liquid injection port 15 and is connected to a control system arranged in the robot. The control system adjusts the pressure in the liquid bag 14 according to the signal received by the pressure sensor, so as to adapt to the ground shape.

[0057] Definition: In this embodiment, the direction in which the locust foot pad 13 contacts the ground is downward when the bionic foot walks on the ground, and vice versa.

[0058] The rear foot sole assembly 2 has the same structure as the front foot sole assembly 1. Both the front foot sole assembly 1 and the rear foot sole assembly 2 include a rigid connecting plate 11, a rigid fixing ring 12 and a locust foot pad 13. The locust foot pad 13 is clamped between the rigid connecting plate 11 and the rigid fixing ring 12, so as to achieve buffering and self-adaptation to the ground.

[0059] Regarding the automatic adaptation of the locust foot pad 13 to the ground, when the bionic foot contacts the ground, the locust foot pad 13 has an approximate multi-curvature contact surface according to the geometry of the locust foot. The area outside the V-shaped groove 16 contacts the ground first, forming multiple local contact points. The contact area and the degree of deformation depend on the ground shape. When the locust foot pad 13 contacts the ground, the liquid in the cavity will flow due to the pressure, causing a small internal pressure change. This change is fed back to the main control unit in the robot through the pressure sensor arranged in the liquid bag 14. The control unit compares the feedback value with the preset target pressure, judges the hardness or roughness of the current ground, and actively adjusts the cavity pressure. The micro pump injects or discharges liquid into the liquid bag 14 from the outside through the liquid injection port 15, so as to achieve the automatic adaptation to the irregular ground.

[0060] As Figure 4 and Figure 8As shown in the drawings, the front support connecting frame 3 comprises a rectangular mounting plate made of metal, and threaded holes are formed on the surface of the mounting plate. The front support connecting frame 3 is connected to the rigid connecting plate 11 of the forefoot sole assembly 1 by means of the threaded holes and screws. In order to facilitate the installation of the forefoot arch assembly 6 and the dorsal muscle elastic sheet 81, two rectangular plates are welded on the surface of the mounting plate perpendicularly to the surface, and the rectangular plates are named as pivot mounting frames 31.

[0061] The two pivot mounting frames 31 are oppositely distributed, and two groups of through holes are formed on the pivot mounting frames 31. One group of the through holes near the outer side is the first hinge hole 32, and the other group of the through holes is the second hinge hole 33. One end of the dorsal muscle elastic sheet 81 is hinged to the first hinge hole 32 to form a forefoot joint, and one end of the forefoot arch 61 in the forefoot arch assembly 6 is hinged to the second hinge hole 33 to form a toe joint. The dorsal muscle elastic sheet 81 and the forefoot arch 61 can rotate along the hinge.

[0062] In order to realize the terrain recognition and feedback adjustment of the foot support posture, a pressure sensor 10 is installed between the front support connecting frame 3 and the rigid connecting plate 11 by means of screws. In addition, a pressure sensor 10 is installed between the mounting plate 51 and the lower leg connecting piece 55 by means of screws. 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 means of screws. The pressure sensor 10 is a six-dimensional force sensor which can be directly used. The pressure sensor 10 can detect the three-directional force and three-directional torque in the forefoot and hindfoot sole position support phase. 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 solving algorithm, the foot bottom support force distribution, ground inclination, foot contact area range and posture direction can be calculated in real time. The structure design and force perception scheme can effectively improve the robustness of the bionic foot on irregular terrain and reduce the risk of falling.

[0063] As shown in the drawings, Figure 5 , Figure 9 and Figure 12 As shown in the drawings, the rear support connecting frame 4 comprises a circular mounting plate, and a rectangular first hinge seat 41 is welded on the surface of the circular mounting plate. A hinge hole is formed on the first hinge seat 41. The rear foot arch 71 in the rear foot arch assembly 7 is hinged to the hinge hole by means of a pin to form a heel joint.

[0064] In order to facilitate the connection of the rear support connecting frame 4 and the rear foot sole assembly 2, threaded holes are formed on the circular mounting plate of the rear support connecting frame 4. 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 sole assembly 2 by means of screws.

[0065] In order to facilitate the installation of the Achilles tendon elastic piece 83 in the bionic elastic connecting piece 8, a rectangular connecting plate is welded on the surface of the rear support connecting frame 4, which is named as the first elastic piece connecting plate 42, and threaded holes are formed on the first elastic piece connecting plate 42, and one end of the Achilles tendon elastic piece 83 is fixed on the first elastic piece connecting plate 42 by means of screws.

[0066] As shown in Figure 1 , Figure 10 and Figure 13 , the ankle joint support 5 comprises a mounting plate 51, a first hinged frame 52, a second elastic piece connecting plate 53, a third elastic piece connecting plate 54 and a calf connecting piece 55, wherein the first hinged frame 52 is welded on the surface of the mounting plate 51, the second elastic piece connecting plate 53 and the third elastic piece connecting plate 54 are welded on the side surface of the mounting plate 51, and the calf connecting piece 55 is detachably connected with the mounting plate 51, and the whole bionic foot can be installed on the calf of the robot by means of the calf connecting piece 55, and the main function of the calf connecting piece 55 is to connect the bionic foot with the calf of the robot, which can be directly used for the existing device.

[0067] The mounting plate 51 is a rectangular plate, threaded holes are formed on the surface of the mounting plate 51, the first hinged frame 52 is a metal frame, hinged holes for hinging with the forefoot arch assembly 6 and the rear foot arch assembly 7 are formed on the first hinged frame 52, and there are two first hinged frames 52 which are oppositely and spacedly distributed on the mounting plate 51.

[0068] The second elastic piece connecting plate 53 and the third elastic piece connecting plate 54 are rectangular metal plates, and the main function of the second elastic piece connecting plate 53 and the third elastic piece connecting plate 54 is to connect with the biceps elastic piece 81 and the Achilles tendon elastic piece 83, threaded holes are formed on the second elastic piece connecting plate 53 and the third elastic piece connecting plate 54, one end of the biceps elastic piece 81 is connected with the second elastic piece connecting plate 53 by means of screws, and one end of the Achilles tendon elastic piece 83 is connected with the third elastic piece connecting plate 54 by means of screws.

[0069] In order to realize the feedback support for the terrain recognition and the posture adjustment, a pressure sensor 10 is installed between the mounting plate 51 and the calf connecting piece 55 by means of screws.

[0070] 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 aluminum alloy with high strength and light weight.

[0071] As shown in Figure 1 , Figure 11 and Figure 13As shown, forefoot arch assembly 6 includes forefoot arch 61, and a U-shaped hinged frame is arranged at both ends of forefoot arch 61, named second hinged frame 62, and a third hinged hole 65 is opened on second hinged frame 62, and forefoot arch 61 can be hinged with rearfoot arch assembly 7 and second hinged hole 33 on front support connecting frame 3 respectively by using second hinged frame 62 and third hinged hole 65.

[0072] Forefoot arch 61 is made of high-strength lightweight aluminum alloy, and the preferred embodiment of the present application is made of existing 6061-T6 aluminum alloy. The cross section of forefoot arch 61 is rectangular, and in order to facilitate the formation of an arch-shaped support structure with rearfoot arch assembly 7 and plantar fascia 9, forefoot arch 61 is arc-shaped in the length direction, and in order to reduce weight, the middle of forefoot arch 61 is designed as a hollow structure.

[0073] Rearfoot arch assembly 7 includes rearfoot arch 71, and a U-shaped hinged frame is fixed at one end of rearfoot arch 71, named third hinged seat 73, and a rectangular hinged seat is arranged at the other end, named second hinged seat 72, and rearfoot arch 71 is hinged with second hinged frame 62 at one end of forefoot arch 61 through second hinged seat 72, and rearfoot arch 71 is hinged with rear support connecting frame 4 through third hinged seat 73.

[0074] Regarding the connection of forefoot arch 61, rearfoot arch 71 and ankle support 5:

[0075] Second hinged seat 72 in rearfoot arch 71 is inserted into second hinged frame 62 at one end of forefoot arch 61, and then placed at first hinged frame 52 of ankle support 5, and then a circular connecting shaft 63 is used to pass through the hinged hole on ankle support 5, and the third hinged hole 65 on second hinged frame 62 and the hinged hole on second hinged seat 72, at this time rearfoot arch 71 and forefoot arch 61 can rotate around connecting shaft 63, in order to make the rotation smooth, a connecting bearing 64 with flange is inserted into the hinged hole of first hinged frame 52, and connecting bearing 64 is fixed on first hinged frame 52 by screws, and both ends of connecting shaft 63 are inserted into connecting bearing 64, which together constitute an ankle.

[0076] Plantar fascia 9 is made of TPU material with high elastic modulus, and is located in the central area of the sole. Plantar fascia 9 is connected with forefoot assembly 1 and rearfoot assembly 2 by screws, and plantar fascia 9, together with forefoot arch 61 and rearfoot arch 71, forms an arch-shaped structure. Because plantar fascia 9 has good stretching and recovery performance, when forefoot arch 61 and rearfoot arch 71 rotate along the hinge during the landing stage of the bionic foot, plantar fascia 9 absorbs vertical impact, and provides lateral flexible recovery force during the support stage, and drives forefoot arch 61 and rearfoot arch 71 to reset when the bionic foot is lifted.

[0077] As Figure 1 ,Figure 2 、 Figure 3 and Figure 13 As shown in the figures, the bionic elastic connecting piece 8 comprises a bionic back muscle elastic piece 81 and a bionic Achilles tendon elastic piece 83, the bionic back muscle elastic piece 81 connects the ankle joint support 5 and the front support connecting frame 3, and the bionic Achilles tendon elastic piece 83 connects the ankle joint support 5 and the rear support connecting frame 4.

[0078] The bionic back muscle elastic piece 81 and the bionic Achilles tendon elastic piece 83 are rectangular pieces, which can be made of metal, or can be made of rubber or thermoplastic polyurethane or similar materials with certain elasticity, and the preferred embodiment adopts 65Mn spring steel pieces, the bionic back muscle elastic piece 81 preferably adopts a spring steel piece with a thickness of 1mm, and the bionic Achilles tendon elastic piece 83 preferably adopts a spring steel piece with a thickness of 2mm. In order to generate tension when the foot is compressed, the bionic back muscle elastic piece 81 and the bionic Achilles tendon elastic piece 83 are pre-bent, and the bending of the bionic back muscle elastic piece 81 and the bionic Achilles tendon elastic piece 83 is preloaded during installation, so that it has 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 bionic back muscle elastic piece 81 and the bionic Achilles tendon elastic piece 83 dynamically stretch to provide elastic force with the deformation of the foot.

[0079] The bionic back muscle elastic piece 81 has two, and the two bionic back muscle elastic pieces 81 are distributed in parallel. In order to facilitate the articulation of the bionic back muscle elastic piece 81 with the first articulation hole 32 on the front support connecting frame 3, a back muscle connecting piece 82 is fixed at one end of the bionic back muscle elastic piece 81 by a screw. The back muscle connecting piece 82 comprises a circular sleeve and a rectangular connecting piece, the connecting piece is connected with the bionic back muscle elastic piece 81 by a screw, and the circular sleeve is sleeved on a mounting pin shaft inserted into the first articulation hole 32.

[0080] In this embodiment, the arrangement of the electrical interface and the adjustment of the liquid in the liquid bag 14 are preferably arranged at the ankle joint support 5, and all sensor signals are collected through a multi-channel signal concentrator. This is a prior art and will not be described here.

[0081] The use process of the bionic foot of the embodiment is as follows:

[0082] When the bottom surface of the forefoot assembly 1 of the bionic foot contacts the ground, at this time the toe joint has a certain angle relative to the ground, and the rotation of the forefoot assembly 1 around the toe joint can make the sole of the bionic foot as close as possible to the ground, so as to ensure that the humanoid robot can realize the action of the forefoot assembly 1 on the ground, and simulate the state of human toes stepping on the ground. When the sole surface is away from the ground and is not subjected to any load, the bionic foot will reset under the action of the bionic back muscle elastic piece 81;

[0083] When the bionic foot only contacts the ground with the rear sole assembly 2, 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-like elastic sheet 83, the rear sole assembly 2 rotates a certain angle around the joint, so that the foot sole can be as close as possible to the ground. The Achilles tendon-like elastic sheet 83 can also reset the foot sole and store energy.

[0084] The buffering process of the bionic foot in this embodiment:

[0085] When the foot is impacted by the ground, the rear sole assembly is first compressed. Under the combined action of gravity and impact force, the forefoot arch 61 and the rear foot arch 71 are lowered, the plantar fascia 9 is stretched and elastic force is generated. At this time, the Achilles tendon-like elastic sheet 83 is compressed to generate elastic deformation to buffer 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 liquid bag 14 in the locust foot pad 13 also provides a certain elasticity and plays a certain buffering role.

[0086] When the robot is in a normal standing state, the bottom surfaces of the forefoot sole assembly 1 and the rear sole assembly 2 simultaneously contact the ground. At this time, through the bionic elastic connecting sheet 8 of the foot, the forefoot sole assembly 1 and the rear sole assembly 2 are pulled to provide support force for the foot, ensuring that the robot is stably supported, and also limiting the foot posture.

[0087] Regarding the limitation of the foot posture:

[0088] When the bionic robot is in a standing or supporting state, in order to maintain the stability of the foot, prevent the foot from being excessively deformed or deflected, and passively or semi-actively “constrain” some degrees of freedom. The limitation of the foot posture here refers to limiting the redundant attitude degrees of freedom of the foot to enhance rigidity and stability. Specifically, it limits the excessive angle of pitch deformation between the forefoot sole assembly 1 and the rear sole assembly 2, which causes the foot to be raised or collapsed.

[0089] Limiting the left and right twisting of the forefoot sole assembly 1 and the rear sole assembly 2 to keep the structure of the foot symmetric and the force balanced under lateral disturbance;

[0090] Limiting the vertical collapse of the arch to prevent the arch structure from collapsing and failing due to load, and maintaining its arched support shape;

[0091] When the bionic robot is in a standing or supporting state, at this time, the bionic elastic connecting sheet 8 is in a stretched state, forming an active traction between the forefoot sole assembly 1 and the rear sole assembly 2, providing longitudinal support force for the foot, and passively limiting the redundant attitude degrees of freedom of the foot, ensuring the rigidity and stability of the foot structure in the supporting phase, and further improving the anti-interference ability and attitude robustness of the whole machine in the standing and walking process.

[0092] The arrangement of the simulated back muscle elastic sheet 81 and the simulated Achilles tendon elastic sheet 83 corresponds to the distribution of back muscles and Achilles tendons in human anatomy, plays a supporting and traction role in the process of robot landing and taking off, and has certain nonlinear stiffness characteristics. The simulated back muscle elastic sheet 81 and the simulated Achilles tendon elastic sheet 83 can adjust the supporting stiffness by changing the angle or material parameters, simulate the physiological process of gradually loading and releasing of the real tendon, provide tensile tension in the swing phase of gait, and the simulated Achilles tendon elastic sheet 83 is used for supporting the heel contact ground after the load rebounds, allowing the user to dynamically adjust the foot support stiffness according to the robot gait, load or terrain conditions, and improving the ground adaptation ability.

[0093] Regarding the adjustment of the foot support stiffness: The simulated back muscle elastic sheet 81 and the simulated Achilles tendon elastic sheet 83 are respectively arranged at the corresponding positions of the back and Achilles tendon of the foot structure, have nonlinear elastic characteristics, and the user can replace different specifications of the simulated back muscle elastic sheet 81 and the simulated Achilles tendon elastic sheet 83, adjust the installation angle or actively control through the parallel micro drive assembly, realize dynamic adjustment of the longitudinal stiffness of the foot structure, and the angle adjustment of the simulated back muscle elastic sheet 81 and the simulated Achilles tendon elastic sheet 83 and the micro drive assembly can be directly used for the existing device. The embodiment preferably does not use the micro drive assembly.

[0094] The technical scheme of the embodiment, by arranging the simulated locust foot pad 13 at the contact position of the forefoot palm assembly 1 and the rear foot palm assembly 2 and the ground, makes the forefoot palm assembly 1 and the rear foot palm assembly 2 have segmented flexibility and ground cushioning function, and can gradually fit locally to complex terrain;

[0095] The use of the plantar fascia 9 and the arched arch to form a spatial flexible structure can provide compression displacement in the initial stage of gait, absorb landing impact and reduce the impact transmission of the rigid foot bottom;

[0096] The simulated back muscle elastic sheet 81 and the simulated Achilles tendon elastic sheet 83 are also used to participate in energy storage and release in the gait cycle, provide additional rebound drive in the second half of the gait, improve the structural dynamic stability and recovery efficiency, effectively inhibit the excessive deformation of the foot in the scene of stepping on a gentle slope or an obstacle, improve the steady-state crossing ability of the robot, and solve the problem that the foot structure of the existing humanoid robot is rigid and lacks flexibility, resulting in difficulty in absorbing landing impact;

[0097] The pressure sensor 10 arranged at three points of the forefoot assembly 1, the rear foot assembly 2 and the ankle support 5 is used to construct a space stress information model, so that the support force, the friction state and the contact posture of different areas of the foot can be obtained in real time; the three-point moment fusion can calculate the foot bottom stress center (COP) and the contact point distribution, so as to judge whether the local terrain is flat, inclined or has obstacles, realize the integration of structure-sensing-control, form a "structure-sensing" coupling response mechanism, so that the foot has certain autonomous judgment and preliminary adaptation ability in the state of no driving, and the robot can realize passive adaptation landing without visual prediction in simple and disordered terrain, simplify the environment dependence, improve the walking robustness, and solve the problem that the existing humanoid robot has single sensing means and is difficult to form a structure and function cooperative feedback mechanism.

[0098] The above examples only illustrate the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the present application.

Claims

1. A humanoid robot bionic foot with autonomous terrain testing capability, characterized in that: The application relates to a bionic foot structure, which comprises a forefoot sole assembly (1), a hindfoot sole assembly (2), an ankle support (5), a forefoot arch assembly (6), a hindfoot arch assembly (7), a bionic elastic connecting piece (8) and a plantar fascia (9), the plantar fascia (9) is flexibly connected to the forefoot sole assembly (1) and the hindfoot sole assembly (2), a front support connecting frame (3) is arranged on the forefoot sole assembly (1), a rear support connecting frame (4) is arranged on the hindfoot sole assembly (2), the forefoot arch assembly (6) is hinged to the front support connecting frame (3), the rear support connecting frame (4) is hinged to the hindfoot arch assembly (7), and the forefoot arch assembly (6) and the hindfoot arch assembly (7) are hinged to the ankle support (5) together; the forefoot arch assembly (6), the hindfoot arch assembly (7) and the plantar fascia (9) cooperatively form an arched composite support structure; pressure sensors (10) are arranged on the front support connecting frame (3), the rear support connecting frame (4) and the ankle support (5) respectively, and the pressure sensors (10) collect mechanical information of the forefoot sole, the hindfoot sole and the ankle joint in real time; The bionic elastic connecting piece (8) connects the front support connecting frame (3), the rear support connecting frame (4) and the ankle support (5) to form an arched structure, and the bionic elastic connecting piece (8) is hinged to the front support connecting frame (3); The forefoot sole assembly (1) and the hindfoot sole assembly (2) further comprise locust-like foot pads (13), the locust-like foot pads (13) are arranged on the bottom surfaces of the forefoot sole assembly (1) and the hindfoot sole assembly (2) and contact the ground, the locust-like foot pads (13) adapt to the ground shape and relieve the landing buffer of the bionic foot; The bionic elastic connecting piece (8) comprises a bionic back muscle elastic piece (81) and a bionic Achilles tendon elastic piece (83), one end of the bionic back muscle elastic piece (81) is hinged to the front support connecting frame (3), the other end is connected to the ankle support (5), and the bionic Achilles tendon elastic piece (83) is connected to the rear support connecting frame (4) and the ankle support (5) respectively; The front support connecting frame (3) comprises two opposite pivot mounting frames (31), the pivot mounting frames (31) are provided with first hinge holes (32) and second hinge holes (33), the bionic back muscle elastic piece (81) of the bionic elastic connecting piece (8) is hinged to the first hinge holes (32) to form a forefoot joint, and the forefoot arch assembly (6) is hinged to the second hinge holes (33) to form a toe joint; The rear support connecting frame (4) comprises a first hinge seat (41) and a first elastic piece connecting plate (42), one end of the hindfoot arch assembly (7) is hinged to the first hinge seat (41), the other end is hinged to the ankle support (5), the bionic Achilles tendon elastic piece (83) of the bionic elastic connecting piece (8) is connected to the first elastic piece connecting plate (42) and the ankle support (5), and the hindfoot arch assembly (7) forms a heel joint at the first hinge seat (41); The ankle support (5) comprises a mounting plate (51), a first hinged frame (52), a second elastic sheet connecting plate (53) and a third elastic sheet connecting plate (54), the first hinged frame (52) is arranged on the mounting plate (51), the forefoot arch assembly (6) and the rearfoot arch assembly (7) are hinged with the ankle support (5) through the first hinged frame (52) to form an ankle, 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), the back muscle elastic sheet (81) and the Achilles tendon elastic sheet (83) in the bionic elastic connecting sheet (8) are connected with the second elastic sheet connecting plate (53) and the third elastic sheet connecting plate (54) respectively; The forefoot assembly (1) and the rearfoot assembly (2) each comprise a rigid connecting sheet (11) and a rigid fixing ring (12), the locust foot pad (13) is arranged between the rigid connecting sheet (11) and the rigid fixing ring (12), the middle part of the locust foot pad (13) passes through the rigid fixing ring (12) and contacts the ground, so that the adhesion and the buffering capacity of the bionic foot to the ground are improved. The locust foot pad (13) comprises a liquid bag (14) for buffering when contacting the ground, the liquid bag (14) is provided with a liquid injection port (15), and the liquid bag (14) can be controlled to inject liquid and discharge liquid.

2. The humanoid robot bionic foot with autonomous terrain test capability according to claim 1, characterized in that: The back muscle elastic sheet (81) and the Achilles tendon elastic sheet (83) are pre-bent, and the pre-bent back muscle elastic sheet (81) and the pre-bent Achilles tendon elastic sheet (83) have elasticity.

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

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