A cormorant leg-flippers foot-walking mechanism

Abstract

The embodiment of the application discloses a kind of imitated cormorant leg-webbed foot walking mechanism, including rear limb connecting frame, leg assembly and webbed foot assembly;Wherein, rear limb connecting frame, for fixedly connecting robot body and the one end of leg assembly;Leg assembly, for driving the movement of robot, at least can realize lateral rotation, longitudinal rotation and height adjustment;Webbed foot assembly, connected to the other end of leg assembly, with web structure, driven by leg assembly can realize height adjustment, pitch angle adjustment, azimuth angle adjustment, roll angle adjustment, and with leg assembly cooperation realizes the swimming action of robot to provide thrust.The application learns the biological characteristics of cormorant, and the mechanism can be used as the driving structure of amphibious robot to improve the swimming efficiency of robot and the adaptability to complex terrain.

Description

Technical Field

[0001] This invention relates to the field of biomimetic amphibious robots, specifically to a cormorant-like leg-webbed walking mechanism. Background Technology

[0002] Bionic amphibious robots are robots based on biomimetic biology, mimicking the structure and propulsion mechanisms of amphibians and applying intelligent control. Over the years, scholars both domestically and internationally have achieved rich research results in the study of the propulsion mechanisms of bionic amphibious robots. Currently, the amphibious propulsion methods for bionic amphibious robots mainly employ legged, walking, wheel-propelled, and combined-drive propulsion systems. Legged amphibious robots have strong terrain adaptability, but require multiple drive units, increasing the redundancy of the drive structure, and their underwater maneuverability is weak. Walking amphibious robots have good swimming performance in water, but their propulsion performance is greatly reduced in environments such as gravel and shallow water, and their ability to adapt to complex environments is weak. Wheel-propelled robots have strong maneuverability on land, but when crawling underwater, the low rotation speed of the robot's spokes and the lateral forces generated can easily interfere with the robot's crawling direction.

[0003] In other research areas, Johansson et al. conducted in vivo experiments on the paddling mechanisms of waterfowl, finding that they not only use drag-based propulsion but also lift-based propulsion. Fan Jizhuang et al., through analysis of fin pressure distribution and flow field structure characteristics, discovered that aquatic frogs combine drag and lift modes during propulsion to improve efficiency. A paper published in Nature by the University of Gothenburg, studying different shaped webbed feet, found that asymmetrical webbed feet are more advantageous for underwater propulsion. In nature, cormorants, as typical waterfowl, possess good terrestrial and aquatic mobility. Therefore, cormorants can be used as a biomimetic model for amphibious robots, achieving amphibious propulsion through webbed feet paddling and walking mechanisms. Summary of the Invention

[0004] To improve the efficiency of robot propulsion in water, enhance the robot's adaptability to terrains such as rugged rocks or soft ground, and effectively overcome problems such as redundancy in the drive mechanism, this invention provides a cormorant-inspired leg-webbed foot walking mechanism. Drawing on the biological characteristics of cormorants, this mechanism can serve as the drive structure for amphibious robots to improve the robot's paddling efficiency and adaptability to complex terrain.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution.

[0006] This invention provides a cormorant-inspired leg-webbed foot locomotion mechanism for use in robots. The leg-webbed foot locomotion mechanism includes: a hind limb connecting frame, a leg assembly, and a webbed foot assembly.

[0007] The hind limb connecting frame is used to fix one end of the robot body and the leg assembly.

[0008] The leg assembly is used to drive the robot's movement and can at least achieve lateral rotation, longitudinal rotation, and height adjustment;

[0009] The webbed foot assembly, connected to the other end of the leg assembly, has a webbed structure and is driven by the leg assembly to achieve height adjustment, pitch angle adjustment, azimuth angle adjustment, and roll angle adjustment. It works in conjunction with the leg assembly to realize the robot's paddling motion to provide thrust.

[0010] Furthermore, the leg assembly includes a lateral swing joint, a parallel multi-drive longitudinal swing joint, and a parallel multi-link structure;

[0011] The lateral swing joint includes a lateral swing motor, an active rotation shaft, and a passive rotation shaft; the parallel multi-drive longitudinal swing joint includes a first longitudinal swing structure and a second longitudinal swing structure; the parallel multi-link structure includes a first multi-link structure and a second multi-link structure.

[0012] The active rotating shaft and the passive rotating shaft are respectively fixedly connected to the first longitudinal swing structure and the second longitudinal swing structure along the longitudinal direction; the first longitudinal swing structure is connected to one end of the first multi-link structure along the longitudinal direction, and the second longitudinal swing structure is connected to one end of the second multi-link structure along the longitudinal direction; the other ends of the first multi-link structure and the second multi-link structure are respectively connected to both sides of the webbed foot assembly along the transverse direction.

[0013] The lateral swing joint drives the parallel multi-drive longitudinal swing joint and the parallel multi-link structure to rotate laterally.

[0014] Furthermore, the hind limb connecting frame includes a longitudinal connecting member, which includes a connecting plate and a connecting ring. The hind limb connecting frame is fixedly connected to the robot body through the connecting plate.

[0015] The connecting ring extends from below the connecting plate. The axial direction of the connecting ring is parallel to the length direction of the connecting plate, and multiple connecting rings are arranged along the length direction of the connecting plate, and multiple rows are arranged along the width direction of the connecting plate. The active rotating shaft and the passive rotating shaft are respectively inserted into one row of connecting rings.

[0016] Furthermore, the hind limb connecting frame also includes a lateral swing joint connector, the lateral swing joint being connected to the swing joint connector and connected to the robot body through the swing joint connector;

[0017] The lateral swing motor is fixedly connected to the lateral swing joint connector, and the active rotation shaft and the passive rotation shaft are rotatably connected to the lateral swing joint connector.

[0018] Furthermore, the swing joint connector is also provided with an arc-shaped through groove corresponding to the lateral rotation trajectory of the parallel multi-drive longitudinal swing joint; the first longitudinal swing structure and the second longitudinal swing structure are also provided with bosses that match the arc-shaped through groove, so that the parallel multi-drive longitudinal swing joint can be stably engaged in the arc-shaped through groove and rotate along a predetermined trajectory.

[0019] Furthermore, the first multi-link structure or the second multi-link structure includes a first link, a second link, a third link, and a fourth link;

[0020] Wherein, one end of the first rod is fixedly connected to the output end of the first longitudinal motor of the first longitudinal swing structure or the second longitudinal swing structure; the second rod is fixedly connected to the output end of the second longitudinal motor of the first longitudinal swing structure or the second longitudinal swing structure; the other end of the first rod is rotatably connected to one end of the third rod; and the other end of the second rod is rotatably connected to one end of the fourth rod.

[0021] The fourth rod is a bent rod with its bend point protruding towards the rear of the robot; the other end of the third rod is rotatably connected to the bend point of the fourth rod; the other end of the fourth rod is rotatably connected to the webbed foot assembly.

[0022] Furthermore, the fin assembly includes a fin connecting frame and a fin rotating motor; the fin rotating motor is fixedly connected to the fin connecting frame;

[0023] The webbed foot assembly further includes a first webbed foot rotating connector and a second webbed foot rotating connector for rotatably connecting with the parallel multi-link structure; the rotation axes of the first webbed foot rotating connector and the second webbed foot rotating connector are oriented towards the length direction of the robot.

[0024] Furthermore, the webbed foot assembly is a multi-joint variable stiffness webbed foot structure, including a foot body, multiple toe structures, a foot variable stiffness adjustment servo, and a flexible cable;

[0025] Each toe structure includes multiple toes, which are connected by pivots, and a spring is fitted on at least one pivot.

[0026] One end of the flexible line is connected to the output end of the foot stiffness adjustment servo, and the other end is sequentially passed through the foot body and each toe, and fixedly connected to the end of the toe structure; the output shaft of the foot stiffness adjustment servo rotates on the flexible line, thereby changing the deformation of the spring by stretching the flexible line, and further changing the stiffness of the webbed foot assembly.

[0027] Furthermore, the webbed foot assembly includes multiple sets of toe structures and attached webs. The webbed structure formed by the multiple sets of toe structures and the webs is fan-shaped, with the arc edge of the fan facing the inner side of the leg-webbed foot walking mechanism. The maximum angle of the fan opening is between 160-180°. When the fan is opened at its maximum angle, the angle between the straight side of the fan and the positive direction of the robot is between 10-20°, which is beneficial for the robot's underwater propulsion.

[0028] On the other hand, the present invention also provides a cormorant-inspired amphibious robot, wherein the cormorant-inspired torso structure includes a head, neck, and abdomen connected in sequence, and the cormorant-inspired amphibious robot also includes a leg-webbed foot walking mechanism as described above connected to the abdomen.

[0029] The leg assembly of the cormorant-like leg-webbed walking mechanism in this embodiment of the invention is used to drive the robot's movement, and can at least achieve lateral rotation, longitudinal rotation, and height adjustment; the webbed foot assembly, connected to the other end of the leg assembly, has a webbed structure, and is driven by the leg assembly to achieve height adjustment, pitch angle adjustment, azimuth angle adjustment, and roll angle adjustment, and cooperates with the leg assembly to realize the robot's paddling action to provide thrust. Compared with conventional walking amphibious robots, it has higher biocompatibility, maneuverability, and adaptability to complex environments, and can have higher maneuverability and stronger propulsion efficiency when paddling underwater.

[0030] The embodiments of the present invention utilize a multi-joint variable stiffness webbed foot structure, enabling the cormorant-inspired robot to adjust the stiffness of its webbed feet while paddling in the water, thereby increasing the thrust and improving efficiency. It also provides better adaptability to complex terrains when walking on land.

[0031] The parallel four-bar leg assembly and multi-joint variable stiffness webbed foot structure proposed in this embodiment of the invention not only enable the cormorant-like robot to walk on all terrains on land, avoiding getting stuck in mud and shallows, greatly enhancing its environmental adaptability, but also enable it to achieve high thrust and high maneuverability in water. The cormorant-like shape also makes it more biocompatible.

[0032] In this embodiment, the two fin components of the cormorant robot's leg-fin walking mechanism are deflected inward. This ensures that when the swimming legs swing outward to turn in the water, the fins still have a large thrust after deflection. In addition, the large opening and inward angle of the fins ensure that the robot is closer to the center of gravity when walking in environments such as beaches, thus enhancing its stability. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of a cormorant-inspired amphibious robot proposed in an embodiment of the present invention;

[0034] Figure 2 yes Figure 1 A schematic diagram of the leg-webbed foot locomotion mechanism of the left hind limb of the Chinese cormorant-inspired amphibious robot;

[0035] Figure 3 yes Figure 1 A schematic diagram of the webbed foot component of the leg-webbed foot locomotion mechanism on the left hind limb of the Chinese cormorant-inspired amphibious robot;

[0036] Figure 4 yes Figure 1 A cross-sectional view of the webbed foot assembly of the leg-webbed foot walking mechanism on the left hind limb of the Chinese cormorant-inspired amphibious robot. Detailed Implementation

[0037] Exemplary embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are for teaching those skilled in the art how to implement the present invention, and are not intended to exhaustively describe all possible ways of the invention, nor to limit the scope of the invention.

[0038] This invention provides a cormorant-inspired amphibious robot. The robot includes a cormorant-inspired torso mechanism and a cormorant-inspired leg-webbed foot locomotion mechanism. Figure 1 As shown, the cormorant-like trunk mechanism includes a head 1, a neck 2, and an abdomen 3 connected in sequence; the cormorant-like leg-webbed foot walking mechanism includes a hind limb connecting frame 4, a leg assembly 5, and a webbed foot assembly 6.

[0039] The head 1 can be equipped with various environmental monitoring devices, such as cameras and infrared sensors, for target recognition or motion closed-loop feedback. The neck 2 is a multi-degree-of-freedom structure, fixedly connected to the head 1 at one end and to the abdomen 3 at the other end. Specifically, the neck 2 may include one or more structures such as multi-links and universal joints, enabling it to rotate at least vertically and horizontally to meet the multi-angle observation needs of the head 1. The hind limb connecting frame 4 is used to fix the abdomen 3 (body) of the robot to one end of the leg assembly 5. The leg assembly 5 is used for the robot's movement and can at least achieve lateral rotation, longitudinal rotation, and length adjustment. The webbed foot assembly 6 is connected to the other end of the leg assembly 5, has a webbed structure, and works with the leg assembly 5 to realize the robot's paddling motion to provide thrust.

[0040] Figure 2 This is a schematic diagram of the leg-webbed foot locomotion mechanism of the left hind limb of a cormorant-inspired amphibious robot. The following explanation uses the structure of the robot's left hind limb as an example to illustrate the structure of the cormorant-inspired leg-webbed foot locomotion mechanism. The structure of the leg-webbed foot locomotion mechanism of the robot's right hind limb is the same as or symmetrical to that of the left hind limb.

[0041] like Figure 2 As shown, the hind limb connecting frame 4 of the cormorant-like leg-webbed-foot walking mechanism includes a longitudinal connecting member 4-1. In this embodiment, the robot's length direction is generally described as longitudinal, and the robot's width direction is described as transverse. The longitudinal connecting member 4-1 includes a connecting plate 4-11 and a connecting ring 4-12. The hind limb connecting frame 4 is fixedly connected to the abdomen 3 via the connecting plate 4-11; the length direction of the connecting plate 4-11 is arranged along the length direction of the robot. The connecting ring 4-12 extends from below the connecting plate 4-11, and the axial direction of the connecting ring 4-12 is parallel to the length direction of the connecting plate 4-11, and multiple connecting rings 4-12 are arranged along the length direction of the connecting plate 4-11. In one embodiment, multiple rows of connecting rings 4-12 can be arranged on a connecting plate 4-11 (one row along the length direction of the connecting plate 4-11), thereby facilitating subsequent assembly. For the aforementioned multi-column arrangement, two scenarios are possible: First, the robot's right and left hind limbs can share a single connecting plate 4-11, with at least four columns of connecting rings 4-12. At least two columns of connecting rings 4-12 are used for connecting the right hind limb leg assembly, and the remaining at least two columns are used for connecting the left hind limb leg assembly. Second, each hind limb can have its own connecting plate 4-11, and each connecting plate 4-11 can have at least two columns of connecting rings 4-12, used for connecting the right and left hind limb leg assemblies respectively. In another embodiment, multiple connecting plates 4-11 can be provided, with each column of connecting rings 4-12 (one column along the length of the connecting plate 4-11) located on one connecting plate 4-11. This facilitates the processing of the hind limb connector 4-1 and saves costs.

[0042] like Figure 2 As shown, the leg assembly 5 of the cormorant-like leg-webbed foot walking mechanism (taking the structure of the left hind limb as an example) includes a lateral swing joint 5-1, a parallel multi-drive longitudinal swing joint 5-2, and a parallel multi-link structure 5-3. The parallel multi-drive longitudinal swing joint 5-2 includes a first longitudinal swing structure 5-21 and a second longitudinal swing structure 5-22 arranged in parallel; the parallel multi-link structure 5-3 includes a first multi-link structure 5-31 and a second multi-link structure 5-32 arranged in parallel.

[0043] In this embodiment, the lateral swing joint 5-1 includes a lateral swing motor 5-11, an active rotation shaft 5-12, and a passive rotation shaft 5-13. The active rotation shaft 5-12 and the passive rotation shaft 5-13 are fixedly connected to the first longitudinal swing structure 5-21 and the second longitudinal swing structure 5-22, respectively. The first longitudinal swing structure 5-21 is longitudinally connected to one end of the first multi-link structure 5-31, and the second longitudinal swing structure 5-22 is longitudinally connected to one end of the second multi-link structure 5-32. The other ends of the first multi-link structure 5-31 and the second multi-link structure 5-32 are transversely connected to both sides of the webbed foot assembly 6. Thus, the parallel arrangement of the first longitudinal swing structure 5-21, the second longitudinal swing structure 5-22, the first multi-link structure 5-31, the second multi-link structure 5-32, and the webbed foot assembly 6 forms an approximately quadrilateral structure in the transverse plane. The structure can be driven by the lateral swing joint 5-1 to rotate the active rotation shaft 5-12, thereby causing the first longitudinal swing structure 5-21, the first multi-link structure 5-31, and the webbed foot assembly 6, which are connected in sequence to the active rotation shaft 5-12, to rotate around the active rotation shaft 5-12, and causing the second longitudinal swing structure 5-22 and the second multi-link structure 5-32, which are connected in sequence to the passive rotation shaft 5-13, to rotate around the passive rotation shaft 5-13.

[0044] In this embodiment, the leg assembly 5 can be understood as including an active side and a passive side. The active side is understood as the side driven by the lateral swing joint 5-1, mainly including the active rotation shaft 5-12, the first longitudinal swing structure 5-21 driven by the active rotation shaft 5-12, and the first multi-link structure 5-31; the passive side is understood as the second longitudinal swing structure 5-22 and the second multi-link structure 5-32 connected to the passive rotation shaft 5-13; the active side and the passive side are connected by the hind limb connecting frame 4 and the webbed foot assembly 6.

[0045] like Figure 2As shown, the connecting rings 4-12 of the hind limb connecting frame 4 are arranged in two rows, with the active rotation shaft 5-12 and the passive rotation shaft 5-13 respectively passing through each row of connecting rings 4-12. To ensure a fixed connection between the lateral swing joint 5-1 and the abdomen 3, the hind limb connecting frame 4 also includes a lateral swing joint connector 4-2. The lateral swing joint 5-1 is connected to the swing joint connector 4-2 and connected to the abdomen 3 via the swing joint connector 4-2. The lateral swing motor 5-11 is fixedly connected to the lateral swing joint connector 4-2, while the active rotation shaft 5-12 and the passive rotation shaft 5-13 are rotatably connected to the lateral swing joint connector 4-2. In this embodiment, to make the rotational motion of the longitudinal swing joint 5-2 around its axis more stable and reliable, the swing joint connector 4-2 is also provided with arc-shaped through slots 4-21 corresponding to the lateral rotation trajectory of the parallel multi-drive longitudinal swing joint 5-2. The arc centers of the two arc-shaped through slots 4-21 coincide with the axes of the active rotation shaft 5-12 and the passive rotation shaft 5-13, respectively. Furthermore, the first longitudinal swing structure 5-21 and the second longitudinal swing structure 5-22 are also provided with bosses that match the arc-shaped through groove 4-21, so that the parallel multi-drive longitudinal swing joint 5-2 can be stably engaged in the arc-shaped through groove 4-21 and rotate along a predetermined trajectory.

[0046] In this embodiment, both the first longitudinal swing structure 5-21 and the second longitudinal swing structure 5-22 include a longitudinal swing motor connector 5-23 and a longitudinal swing motor 5-24. The longitudinal swing motor connector 5-23 covers the outside of the longitudinal swing motor 5-24 and is fixedly connected to it. One end of the connector forms a boss that matches the arc-shaped through slot 4-21 and is slidably connected to the transverse swing joint connector 4-2. The other end extends into a connecting ear and is fixedly connected to either the active rotation shaft 5-12 or the passive rotation shaft 5-13. Thus, the longitudinal swing motor connector 5-23 can be driven to rotate by the transverse swing motor 5-11. In this embodiment, both the first longitudinal swing structure 5-21 and the second longitudinal swing structure 5-22 include two longitudinal swing motors 5-24. The output shafts of the longitudinal swing motors 5-24 of the first longitudinal swing structure 5-21 and the second longitudinal swing structure 5-22 are fixedly connected to the first multi-link structure 5-31 and the second multi-link structure 5-32, respectively.

[0047] In this embodiment, the parallel first multi-link structure 5-31 and the second multi-link structure 5-32 are each driven by two sets of longitudinal swing motors 5-24, that is, driven by a total of four longitudinal swing motors 5-24. The following description uses the active side first multi-link structure 5-31 as an example; the passive side second multi-link structure 5-32 has a similar connection relationship and structure. Figure 2In the design, the first longitudinal motor 5-241 is located near the tail end of the robot, and the second longitudinal motor 5-242 is located slightly forward. The output end of the first longitudinal motor 5-241 is fixedly connected to one end of the first rod 5-311 and can drive the first rod 5-311 to rotate. The output end of the second longitudinal motor 5-242 is fixedly connected to one end of the second rod 5-312 and can drive the second rod 5-312 to rotate. The other ends of the first rod 5-311 and the second rod 5-312 are rotatably connected to one end of the third rod 5-313 and the fourth rod 5-314, respectively. The fourth rod 5-314 is a bent rod with its bending point protruding towards the rear of the robot. The other end of the third rod 5-313 is rotatably connected to the bending point of the fourth rod 5-314, and the other end of the fourth rod 5-314 is rotatably connected to the webbed foot assembly 6.

[0048] The parallel multi-link structure 5-3 described above is driven by four longitudinal swing motors 5-24, which can realize the height adjustment, pitch angle adjustment, azimuth angle adjustment and roll angle adjustment of the webbed foot assembly 6, making it easy for the robot to achieve a variety of movements and adapt to complex terrain.

[0049] like Figure 3 As shown, the webbed foot assembly 6 in this embodiment includes a webbed foot connecting frame 6-1 and a webbed foot rotating motor 6-2; the webbed foot rotating motor 6-2 is fixedly connected to the webbed foot connecting frame 6-1. The webbed foot assembly 6 also includes a first webbed foot rotating connector 6-3 and a second webbed foot rotating connector 6-4 for rotatably connecting with the parallel multi-link structure 5-3. The first webbed foot rotating connector 6-3 and the second webbed foot rotating connector 6-4 are respectively disposed on both sides of the webbed foot rotating motor 6-2, and are rotatably connected to the two fourth rods 5-34 of the parallel multi-link structure 5-3, with the rotation axis facing the length direction of the robot. This allows the webbed foot assembly 6 to swing under the drive of the lateral swing electrode 5-11. If the multi-links are parallel and of equal total length, the bottom surface of the webbed foot assembly 6 can remain parallel to the initial position when driven only by the lateral swing electrode 5-11.

[0050] In this embodiment, the webbed foot assembly 6 can be driven to rotate longitudinally by the webbed foot rotation motor 6-2. The output end of the webbed foot rotation motor 6-2 is fixedly connected to the first webbed foot rotation connector 6-3; the other side of the motor, axially opposite to the output end of the webbed foot rotation motor 6-2, is rotatably connected to the second webbed foot rotation connector 6-4. Thus, rotation of the output end of the webbed foot rotation motor 6-2 can drive the webbed foot connecting frame 6-1 and its fixedly connected components to rotate together, thereby enabling the robot's webbed foot assembly 6 to perform paddling motion.

[0051] In this embodiment, the webbed foot assembly 6 further includes a foot 6-5. The foot 6-5 is fixedly connected to the lower part of the webbed foot connecting frame 6-1 and is driven by the webbed foot rotation motor 6-2 to rotate with the webbed foot connecting frame 6-1. Further, the foot 6-5 includes a foot body 6-9, multiple toe structures, and webs 6-11, wherein the toe structures are connected to the foot body 6-9, and the webs 6-11 are fixedly connected to the lower part of the toe structures. In a preferred embodiment, the webbed foot assembly 6 is designed as a multi-joint variable stiffness webbed foot structure. Figure 3 and Figure 4As shown, the webbed foot assembly 6 also includes a foot stiffness adjustment servo 6-6. The foot stiffness adjustment servo 6-6 is fixedly connected to the upper part of the webbed foot connecting frame 6-1. The output shaft of the foot stiffness adjustment servo 6-6 is fixedly connected to the flexible line connector 6-8, and the flexible line 6-7 is fixedly connected by the flexible line connector 6-8. Thus, rotating the output shaft of the foot stiffness adjustment servo 6-6 applies force to the flexible line 6-7, thereby stretching the flexible line 6-7. The flexible line 6-7 is a non-elastic line, such as a thin steel wire or fishing line. The flexible line 6-7 passes through the hole 6-10 on the foot 6-5, and sequentially passes through the foot body 6-9, the first toe 6-81, the second toe 6-82, and the third toe 6-83, and is fixedly connected to the end of the toe 6-83. The first toe 6-81 is rotatably connected to the foot body 6-9 via the first pivot 6-101. The first toe 6-81, the second toe 6-82, and the third toe 6-83 are rotatably connected via the second pivot 6-102 and the third pivot 6-103, respectively. A V-shaped spring is fitted on one or more of the first pivot 6-101, the second pivot 6-102, and the third pivot 6-103. Thus, the stiffness of the foot 6-5 of the webbed foot assembly 6 can be adjusted by the foot stiffness adjustment servo 6-6 pulling the flexible line 6-7 to adjust the deformation of the V-shaped springs fitted on the first pivot 6-101, the second pivot 6-102, and the third pivot 6-103. In this embodiment, the first toe 6-81, the second toe 6-82, and the third toe 6-83 constitute a toe structure. In other embodiments, a toe structure can also be composed of more or fewer toes, and the number of pivots between the toes can be adjusted accordingly. The three pivots provide an arc-shaped water-facing surface during movement, better utilizing underwater lift while minimizing structural redundancy. Between the foot body 6-9, the first toe 6-81, the second toe 6-82, and the third toe 6-83, the first pivot 6-101, the second pivot 6-102, and the third pivot 6-103 are positioned slightly below one end of the toe body. A stop structure above the pivots can limit the angle, allowing the entire toe structure to bend only downwards. The effect of this design is that, during the paddling phase of the fin assembly 6, the structure can maintain the stability of the fin assembly 6 and provide the maximum frontal surface, without requiring the foot stiffness adjustment servo 6-31 to maintain the state of the fin assembly 6 or reducing the energy consumption of the foot stiffness adjustment servo 6-31 in maintaining the state of the fin assembly 6. In this embodiment, the toe structure is set in multiple groups, preferably four groups. In other embodiments, more or fewer toe structures may be set. In addition, the fin structure formed by the multiple groups of toe structures and the attached fins 6-11 in this embodiment is fan-shaped, with the arc edge of the fan facing the inside of the leg-fin walking mechanism, and the maximum opening angle of the fan is between 160-180°.The four toe structures, arranged clockwise from the front (counterclockwise for the right leg), are the first, second, third, and fourth toe structures. The angles between each toe structure are evenly distributed, and the first toe structure is not directly facing the robot's positive direction, but rather forms an angle between it and the robot's positive direction of 10-20° (e.g.). Figure 2 (The leg assembly 5 is shown in its vertical position). In this embodiment, the two left and right webbed feet assemblies 6 of the cormorant robot's leg-finger walking mechanism are deflected inwards. This ensures that when the swimming legs swing outwards to turn in the water, the webbed feet still have a large thrust after deflection. In addition, the large opening and inward angle of the webbed feet ensure that the robot is closer to its center of gravity when walking in environments such as beaches, thus enhancing its stability.

[0052] The effect of designing the foot 6-5 as a multi-joint variable stiffness webbed foot structure in this embodiment is that when the robot needs to mimic cormorant paddling motion, the flexible line 6-7 can be tightened during the drag mode to increase the stiffness of the foot 6-5, thereby preventing the foot 6-5 from deforming when subjected to force; during the lift mode, a certain length of the flexible line 6-7 can be released, allowing the foot 6-5 to contract at a certain angle to form an arc surface to utilize lift motion, or the foot 6-5 can be contracted to its minimum shape to reduce the resistance encountered when the foot 6-5 slides forward.

[0053] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A cormorant-like leg-webbed foot walking mechanism, characterized in that, The leg-finger walking mechanism includes: a hind limb connecting frame (4), a leg assembly (5), and a fingertip assembly (6); The hind limb connecting frame (4) is used to fix one end of the robot body and the leg assembly (5); The leg assembly (5) is used to drive the movement of the robot and can at least achieve lateral rotation, longitudinal rotation and height adjustment; The webbed foot assembly (6) is connected to the other end of the leg assembly (5), has a webbed structure, and is driven by the leg assembly (5) to realize height adjustment, pitch angle adjustment, azimuth angle adjustment and roll angle adjustment, and cooperates with the leg assembly (5) to realize the robot's paddling action to provide thrust; The leg assembly (5) includes a lateral swing joint (5-1), a parallel multi-drive longitudinal swing joint (5-2), and a parallel multi-link structure (5-3); The lateral swing joint (5-1) includes a lateral swing motor (5-11), an active rotation shaft (5-12), and a passive rotation shaft (5-13); the parallel multi-drive longitudinal swing joint (5-2) includes a first longitudinal swing structure (5-21) and a second longitudinal swing structure (5-22); the parallel multi-link structure (5-3) includes a first multi-link structure (5-31) and a second multi-link structure (5-32). The active rotating shaft (5-12) and the passive rotating shaft (5-13) are fixedly connected longitudinally to the first longitudinal swing structure (5-21) and the second longitudinal swing structure (5-22), respectively; the first longitudinal swing structure (5-21) is longitudinally connected to one end of the first multi-link structure (5-31), and the second longitudinal swing structure (5-22) is longitudinally connected to one end of the second multi-link structure (5-32); the other ends of the first multi-link structure (5-31) and the second multi-link structure (5-32) are transversely connected to both sides of the webbed foot assembly (6); The lateral swing joint (5-1) drives the parallel multi-drive longitudinal swing joint (5-2) and the parallel multi-link structure (5-3) to rotate laterally; The first multi-link structure (5-31) or the second multi-link structure (5-32) includes a first link (5-311), a second link (5-312), a third link (5-313) and a fourth link (5-314); Wherein, one end of the first rod (5-311) is fixedly connected to the output end of the first longitudinal motor (5-241) of the first longitudinal swing structure (5-21) or the second longitudinal swing structure (5-22); the second rod (5-312) is fixedly connected to the output end of the second longitudinal motor (5-242) of the first longitudinal swing structure (5-21) or the second longitudinal swing structure (5-22); the other end of the first rod (5-311) is rotatably connected to one end of the third rod (5-313); the other end of the second rod (5-312) is rotatably connected to one end of the fourth rod (5-314); The fourth rod (5-314) is a bent rod with its bending point protruding towards the rear of the robot; the other end of the third rod (5-313) is rotatably connected to the bending point of the fourth rod (5-314); the other end of the fourth rod (5-314) is rotatably connected to the webbed foot assembly (6).

2. The leg-webbed foot walking mechanism according to claim 1, characterized in that, The hind limb connecting frame (4) includes a longitudinal connecting member (4-1), the longitudinal connecting member (4-1) includes a connecting plate (4-11) and a connecting ring (4-12), and the hind limb connecting frame (4) is fixedly connected to the robot body through the connecting plate (4-11); The connecting ring (4-12) extends from below the connecting plate (4-11). The axial direction of the connecting ring (4-12) is parallel to the length direction of the connecting plate (4-11), and multiple connecting rings (4-12) are arranged along the length direction of the connecting plate (4-11), and multiple rows are arranged along the width direction of the connecting plate (4-11). The active rotating shaft (5-12) and the passive rotating shaft (5-13) are respectively inserted into one row of connecting rings (4-12).

3. The leg-webbed foot walking mechanism according to claim 2, characterized in that, The hind limb connecting frame (4) also includes a lateral swing joint connector (4-2), the lateral swing joint (5-1) is connected to the swing joint connector (4-2), and is connected to the robot body through the swing joint connector (4-2); The transverse swing motor (5-11) is fixedly connected to the transverse swing joint connector (4-2), and the active rotation shaft (5-12) and the passive rotation shaft (5-13) are rotatably connected to the transverse swing joint connector (4-2).

4. The leg-webbed foot walking mechanism according to claim 3, characterized in that, The swing joint connector (4-2) is also provided with an arc-shaped through groove (4-21) corresponding to the lateral rotation trajectory of the parallel multi-drive longitudinal swing joint (5-2); the first longitudinal swing structure (5-21) and the second longitudinal swing structure (5-22) are also provided with bosses that match the arc-shaped through groove (4-21), so that the parallel multi-drive longitudinal swing joint (5-2) can be stably engaged in the arc-shaped through groove (4-21) and rotate along a predetermined trajectory.

5. The leg-webbed foot walking mechanism according to claim 1, characterized in that, The webbed foot assembly (6) includes a webbed foot connecting frame (6-1) and a webbed foot rotating motor (6-2); the webbed foot rotating motor (6-2) is fixedly connected to the webbed foot connecting frame (6-1); The webbed foot assembly (6) further includes a first webbed foot rotating connector (6-3) and a second webbed foot rotating connector (6-4) for rotatably connecting with the parallel multi-link structure (5-3); the rotation axes of the first webbed foot rotating connector (6-3) and the second webbed foot rotating connector (6-4) are oriented toward the length direction of the robot.

6. The leg-webbed foot walking mechanism according to claim 1, characterized in that, The webbed foot assembly (6) is a multi-joint variable stiffness webbed foot structure, including a foot body (6-9), multiple toe structures, a foot variable stiffness adjustment servo (6-6), and a flexible line (6-7). Each toe structure includes multiple toes, which are connected by pivots, and a spring is fitted on at least one pivot. One end of the flexible line (6-7) is connected to the output end of the foot stiffness adjustment servo (6-6), and the other end is sequentially passed through the foot body (6-9) and each toe, and fixedly connected at the end of the toe structure; the output shaft of the foot stiffness adjustment servo (6-6) rotates on the flexible line (6-7), thereby changing the deformation of the spring by stretching the flexible line (6-7), and further changing the stiffness of the webbed foot assembly (6).

7. The leg-webbed foot walking mechanism according to claim 1, characterized in that, The webbed foot assembly (6) includes multiple sets of toe structures and attached webs (6-11). The web structure formed by the multiple sets of toe structures and the webs (6-11) is fan-shaped, with the arc edge of the fan facing the inside of the leg-webbed foot walking mechanism. The maximum angle of the fan opening is between 160-180°. When the fan is opened at its maximum angle, the angle between the straight side of the fan and the positive direction of the robot is between 10-20°, which is beneficial for the underwater propulsion of the robot.

8. A cormorant-inspired amphibious robot, wherein its cormorant-inspired torso structure comprises a head (1), a neck (2), and an abdomen (3) connected in sequence, characterized in that, The cormorant-like amphibious robot also includes a leg-webbed foot walking mechanism as described in any one of claims 1 to 7 connected to the abdomen (3).

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