Bionic kicking and jumping foot of lunar surface jumping robot

Abstract

A bionic pedaling and jumping foot of a lunar surface jumping robot belongs to the technical field of engineering bionics, and comprises a sole component, three bionic toes and a bionic toe tip, the sole assembly is provided with a leg connecting piece and a plurality of through cavities; the bionic toes are connected with the sole assembly through first metatarsophalangeal joints to form axial symmetry distribution, the included angle between every two adjacent toes is 20 degrees, and each bionic toe is provided with a bionic toe cavity. The tail end of the bionic toe tip is provided with a bionic foot thorn, and the bionic toe tip is connected with the bionic toe through a second metatarsophalangeal joint; the rigid rope penetrates through the sole cavity and the bionic toe cavity, one end of the rigid rope is connected with the leg bouncing mechanism, and the other end of the rigid rope is fixed to the round rod of the bionic toe tip. Foot end joints are kept in a relaxed posture by torsion springs in a natural state; the rigid rope pulls the tension spring to store energy and is locked by the ratchet mechanism, and the toes are synchronously driven to contract to form a sand grabbing and fixing state; during starting, the motor drives the ratchet wheel to release energy, the tension spring contracts to realize pedaling action, and the torsion spring synergistically releases energy to enhance jumping performance. A high-adaptability foot end solution is provided for the celestial body exploration robot, and the trafficability and movement stability of complex terrains are effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of engineering bionics, and specifically relates to an adaptive high-adhesion bionic jumping foot for soft ground, which realizes the sand fixation, current limiting and energy conversion functions of the jumping mechanism in the soft ground environment of the lunar surface, and is suitable for the foot end design of an exploration robot for granular medium terrain on the lunar surface. Background Art

[0002] As deep space exploration missions expand to celestial bodies with complex surface characteristics, such as the moon, efficient movement in the soft lunar environment has become a technical problem that needs to be overcome. The low load-bearing characteristics and particle fluidity of lunar soil cause traditional mobile platforms to sink and slip easily, which seriously restricts exploration efficiency. Jumping robots have become ideal carriers for deep space exploration due to their strong ability to cross obstacles and wide terrain adaptability. However, the energy dissipation and insufficient adhesion of their feet in the soft lunar environment are particularly prominent, and bionic design is needed to improve their motion performance.

[0003] Existing jumping robots mostly use rigid structures at the foot end, which is difficult to adapt to the complex mechanical response of soft media. The rheological properties of the particles cause significant sinking when touching the ground, the direction of the reaction force of the take-off deviates from the ideal trajectory, and the vertical energy conversion efficiency is low; at the same time, the lack of a dynamic adaptation mechanism leads to a serious loss of horizontal adhesion and insufficient stability in continuous jumping. The traditional solution alleviates sinking by increasing the sole area, but it leads to an increase in the mass of the mechanism and a decrease in the energy storage density, which leads to a "quality-efficiency" contradiction.

[0004] Jerboas are small desert jumping animals, and their unique jumping motion allows them to survive efficiently in desert environments. Jerboas rely on their slender hind limbs and special toe structures to complete efficient jumping when jumping in the desert. The toe posture of jerboas constantly changes during jumping, and the three toes cooperate with each other to achieve the effect of grabbing and fixing sand, and the elastic toe joints provide the jerboas with forward propulsion when taking off. The tip of the jerboas' toenails can reduce the contact area with the soil, so that they can be better inserted into the sand, and the side groove-shaped curved surface allows the toenails to interlock with the sand, and a forward traction force is generated through the dynamic insertion and extraction mechanism of the toenails and the sand. Jerboas have the advantage of efficient and stable jumping on soft ground, so this application designs a bionic jumping foot with high adaptability and adhesion for soft ground based on the jerboas' toe structure. Summary of the invention

[0005] Aiming at the problems that the foot end of the hopping robot is prone to sink into the lunar soil, has large energy dissipation and low hopping efficiency in the soft lunar surface environment, based on the efficient sand-crossing biomechanical characteristics of the jerboa's toes in the sand, the present invention proposes a bionic kicking foot for a lunar hopping robot, aiming to optimize the foot end structure through the principle of bionics, improve the takeoff adhesion, energy conversion efficiency and obstacle-crossing ability of the hopping robot in the lunar soil environment with high particle fluidity, and provide a motion solution for deep space exploration robots to adapt to soft terrains.

[0006] The present invention provides a bionic hopping foot with self-adaptability and high adhesion performance. The technical problem to be solved is the unstable hopping and slipping phenomenon of the hopping robot on soft ground, so as to improve the hopping ability and hopping stability of the legged hopping robot on soft ground.

[0007] The present invention mainly takes the jerboa's foot as the bionic feature unit, mainly including the jerboa's foot sole structure, the jerboa's three-toe structure, and the jerboa's toenail structure. According to the structural and functional characteristics of the above biological coupling units, a bionic kicking foot for a lunar hopping robot is designed.

[0008] A bionic kicking foot for a lunar hopping robot includes a foot sole assembly, three bionic toes and bionic toe tips; The foot sole assembly is provided with a leg connecting piece and a plurality of through cavities; Each bionic toe is connected to the foot sole assembly through a first metatarsophalangeal joint, forming an axisymmetric distribution with an included angle of 20° between adjacent toes. The bionic toe has a bionic toe cavity; The end of the bionic toe tip is provided with a bionic foot thorn. The bionic toe tip is connected to the bionic toe through a second metatarsophalangeal joint; A rigid rope passes through the foot sole cavity and the bionic toe cavity. One end of the rigid rope is connected to the leg bouncing mechanism, and the other end of the rigid rope is fixed to the circular rod of the bionic toe tip.

[0009] The structure of the first metatarsophalangeal joint is: the first connection hole of the foot sole assembly and the second connection port of the bionic toe are hinged by a locking screw, and torsion springs are symmetrically arranged outside the connection port.

[0010] The structure of the second metatarsophalangeal joint is: the third connection port of the bionic toe and the fourth connection hole of the bionic toe tip are hinged by a locking screw, and a torsion spring is configured.

[0011] The bionic foot thorn is a groove-shaped curved surface structure, the bottom surface of which is conical, and is used for embedding into the lunar soil and generating horizontal adhesion; the groove-shaped curved surface of the bionic foot thorn interlocks with the lunar soil during the takeoff stage to generate an ideal takeoff reaction force in the 45° direction.

[0012] The traction action of the rigid rope is driven by the motor of the bouncing mechanism, locked by the ratchet mechanism during energy storage, and drives the three bionic toes to contract towards the foot sole during release, forming a state of grasping and fixing the sand.

[0013] The torsion springs of the first metatarsophalangeal joint and the second metatarsophalangeal joint buffer impact force and store energy when touching the ground, and release elastic potential energy in coordination when taking off to enhance vertical jumping force.

[0014] The sole component, bionic toe and bionic toe tip are made of 3D printed PLA material, and the three bionic toe tips are equal in length and symmetrical in structure.

[0015] The circular rod at the toe tip is fixedly connected to the end of the rigid rope, and the centripetal contraction movement of the toes is achieved through axial tension.

[0016] The bionic toe cavity is coaxially connected with the sole cavity to provide a movement channel for the rigid rope.

[0017] The torsion spring angle of the first metatarsophalangeal joint is 170°, and the torsion spring angle of the second metatarsophalangeal joint is 120°, so as to maintain the natural unfolding posture of the foot end.

[0018] Working process of the present invention: In the natural state, the end joint of the foot, namely the first metatarsophalangeal joint, is maintained in a stretched posture by a torsion spring, with the metatarsophalangeal joint at 170° and the interphalangeal joint at 120°, forming a bionic three-toe deployment configuration; in the preparation stage for take-off, the three bionic toes are driven toward the sole of the foot by rigid rope traction, and the main spring is stretched synchronously to complete the storage of elastic potential energy. The ratchet mechanism realizes mechanical energy locking and maintains the stored energy state. At this time, the bionic spur is embedded in the lunar soil, and the toes work together to produce a sand-grabbing and sand-fixing effect; in the take-off stage, the motor triggers the ratchet release, the main spring rapidly retracts to drive the leg to extend, and at the same time, the torsion springs of each joint work together to release the stored elastic potential energy. The three bionic toe structures rely on the horizontal adhesion provided by the bionic spur and the vertical thrust of the torsion spring to achieve directional energy release at the optimal take-off angle of 45°, significantly improving the jumping height and trajectory stability on the soft lunar surface.

[0019] The bottom surface of each bionic toe tip is arranged with a groove-shaped bionic spur that imitates the shape of a jerboa's toenail. The conical design reduces insertion resistance. When touching the ground, the three toes are passively expanded by the impact force and store energy through torsion spring buffering. During the power storage stage, the motor pulls the three toes to contract and aggregate particles to form a dense load-bearing area. When taking off, the bionic spur surface generates a directional reaction force to achieve an ideal take-off angle of 45°. Ground adaptability is achieved by presetting a 20° toe angle. On hard terrain, the toes make priority contact, and on soft terrain, the sole of the foot bears full pressure.

[0020] The first metatarsophalangeal joint and the second metatarsophalangeal joint form the posture of the jerboa foot in a natural state; the rigid rope controls the grasping movement of the jumping foot. The bionic jumping foot is an axisymmetric structure as a whole. The bionic toes on both sides of the jumping foot are connected in the same way as the middle toe, and the angle between two adjacent toes is 20°. The metatarsophalangeal joint composed of the bionic sole, three bionic toes and toe tips cooperates with torsion springs at different angles to simulate the movement structure characteristics of the jerboa toe joint, and plays a role in buffering and absorbing energy. The locking screws correspond to the jerboa toe joint, and the torsion springs simulate the buffering effect of the metatarsophalangeal joint; the toe tips, as the part that contacts the sand most directly, are connected to the ends of the three bionic toes respectively, and are connected by locking screws. A foot spur structure is designed on the bottom surface of the toe tips to simulate the toenail structure of the jerboa, so that it can continuously provide forward adhesion during jumping, thereby improving the stability of jumping.

[0021] When the jumping foot lands from the air, due to the mobility of the joints and torsion springs, the three-toe structure is impacted and deployed, increasing the ground contact area and reducing the amount of sinking, which not only prevents the jumping robot from sinking, but also plays a certain buffering role. When taking off, the rigid rope drives the toe joint structure to rotate to complete the grasping action, so that the sand particles on the sole of the foot gather, and the toes and foot spurs work together to fix the sand and limit the flow, making the take-off performance better and more stable.

[0022] The working principle of the present invention is as follows: In the natural state, the joint angle of the bionic jumping foot shows the natural angle of the torsion spring in the relaxed state. In the take-off preparation stage, the tension spring is charged by pulling the rigid rope. The balance is maintained by the ratchet mechanism during the charging process. The ratchet mechanism achieves mechanical energy locking during the charging process. At the same time, the foot end connected by the rigid rope begins to deform synergistically, and the three-toe structure connected to the sole of the foot begins to shrink toward the palm. The foot end grabs the sand and fixes the sand under the action of the foot spurs and toes. In the take-off stage of the jumping robot, the motor rotates to trigger the ratchet mechanism to release elastic potential energy, and the pre-tightened tension spring is quickly tightened to complete the action of pushing off the ground. The torsion spring at the foot end plays a synergistic role in jumping. When the foot end leaves the ground, the torsion spring and the spring release elastic potential energy at the same time, which improves its jumping performance. The real object is made of PLA material through 3D printing technology. The three toes are designed to be equal in length, and the ends of the rope are connected to the round rods of the toe bones to achieve the gripping effect through stretching.

[0023] The beneficial effects of the present invention are: 1. Three-toe bionic structure design: The unique bionic three-toe structure of the present invention greatly improves the jumping performance of the jumping robot. The interaction between different toes can make the sand between the toes appear compact, thereby playing the role of sand fixation and flow limitation. The foot structure combined with the trapezoidal toe gap that is narrow at the top and wide at the bottom plays a role in sand fixation and flow limitation.

[0024] 2. Multi-joint torsion spring jump enhancement system: Based on the elastic mechanical properties of the jerboa's metatarsophalangeal joint, a foot-end design with a multi-joint torsion spring is adopted. When the robot's foot touches the ground, the torsion spring stores energy; when taking off, the torsion spring releases energy, generating an additional upward driving force, thereby enhancing the jumping performance of the jumping robot. At the same time, the torsion spring has a shock-absorbing effect when the robot lands, which can effectively reduce the impact force, protect the structure of the robot, and prepare for the next jump by elastic recovery of energy.

[0025] 3. High adhesion effect of bionic foot spurs: This design targets the role of the jerboa's toenails during the jerboa's jumping process, extracts the curve characteristics of the toenails as bionic elements, significantly improves the adhesion compared with traditional foot spurs, effectively inhibits the phenomenon of slipping during takeoff, and ensures the stability of continuous jumping. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the front view of the present invention; Figure 2 is the right view of the present invention; Figure 3 is the bottom view of the present invention; Figure 4 is the perspective view of the present invention; Figure 5 is the perspective view of the foot sole assembly imitating the present invention; Figure 6 is the perspective view of the bionic toe tip of the present invention; Figure 7 is the perspective view of the bionic toe of the present invention; Figure 8 is the exploded view of the present invention.

[0027] In the figure: 1 - foot sole assembly; 2 - bionic toe; 3 - bionic toe tip; 4. leg connecting piece; 5a - first joint connecting hole; 5b - second joint connecting hole; 5c - third joint connecting hole; 5d - fourth joint connecting hole; 6 - foot sole cavity; 7 - bionic foot spur; 8 - round rod; 9 - bionic toe cavity; 10 - torsion spring; 11 - locking screw; 12 - rigid rope. DETAILED DESCRIPTION OF THE INVENTION

[0028] As Figures 1 to 8 shown, a bionic kicking and jumping foot for a lunar jumping robot includes a foot sole assembly 1, three bionic toes 2 and a bionic toe tip 3; The foot sole assembly 1 is provided with a leg connecting piece 4 and a plurality of through cavities 6; Each bionic toe 2 is connected to the foot sole assembly 1 through the first metatarsophalangeal joint, forming an axisymmetric distribution with an angle of 20° between adjacent toes. The bionic toe 2 has a bionic toe cavity 9, which cooperates with Figure 7 shown; The end of the bionic toe tip 3 is provided with a bionic foot thorn 7, and the bionic toe tip 3 is connected to the bionic toe 2 through the second metatarsophalangeal joint; The rigid rope 12 passes through the sole cavity 6 and the bionic toe cavity 9. One end of the rigid rope 12 is connected to the leg bouncing mechanism, and the other end of the rigid rope 12 is fixed to the circular rod 8 of the bionic toe tip 3.

[0029] The structure of the first metatarsophalangeal joint is as follows: the first connection hole 5a of the sole component 1 and the second connection port 5b of the bionic toe 2 are hinged by a locking screw 11, and torsion springs 10 are symmetrically arranged outside the connection port. The included angle of the torsion spring 10 is 170°; The structure of the second metatarsophalangeal joint is as follows: the third connection port 5c of the bionic toe 2 and the fourth connection hole 5d of the bionic toe tip 3 are hinged by a locking screw 11, and a torsion spring 10 is configured. The included angle of the torsion spring 10 is 120°.

[0030] The bionic foot thorn 7 is a groove-shaped curved surface structure, and its bottom surface is conical, which is used to embed lunar soil and generate horizontal adhesion; the groove-shaped curved surface of the bionic foot thorn 7 is interlocked with the lunar soil during the takeoff stage to generate an ideal takeoff reaction force in the 45° direction.

[0031] The traction action of the rigid rope is driven by the motor of the bouncing mechanism, locked by the ratchet mechanism during energy storage, and drives the three bionic toes 2 to contract towards the sole when released, forming a state of grasping and fixing sand.

[0032] The torsion springs 10 of the first metatarsophalangeal joint and the second metatarsophalangeal joint buffer the impact force and store energy when touching the ground, and release the elastic potential energy synergistically when taking off to enhance the vertical jumping force.

[0033] The sole component 1, the bionic toe 2 and the bionic toe tip 3 are made of 3D printing PLA material, and the lengths of the three bionic toe tips 3 are equal and the structures are symmetrical.

[0034] The circular rod 8 of the toe tip 3 is fixedly connected to the end of the rigid rope, and the centripetal contraction movement of the toe is realized through axial tension.

[0035] The bionic toe cavity 9 and the sole cavity 6 are coaxially penetrated to provide a movement channel for the rigid rope.

[0036] The included angle of the torsion spring 10 of the first metatarsophalangeal joint is 170°, and the included angle of the torsion spring 10 of the second metatarsophalangeal joint is 120°, maintaining the natural unfolding posture of the foot end.

[0037] The working process of the present invention: Such as Figures 1 to 8As shown, in the natural state, the foot end joint, i.e. the first metatarsophalangeal joint, is maintained in a stretched posture by a torsion spring 10, with the metatarsophalangeal joint at 170° and the interphalangeal joint at 120°, forming a bionic three-toe deployment configuration; in the take-off preparation stage, the three bionic toes are driven to retract toward the sole of the foot by rigid rope traction, and the main spring is stretched synchronously to complete the elastic potential energy storage, and the ratchet mechanism realizes mechanical energy locking and maintains the stored power state. At this time, the bionic foot spur 7 is embedded in the lunar soil, and the toes work together to produce a sand grabbing and fixing effect; in the take-off stage, the motor triggers the ratchet release, and the main spring rapidly retracts to drive the leg to extend. At the same time, the torsion springs 10 in each joint work together to release the stored elastic potential energy. The three bionic toe 2 structures rely on the horizontal adhesion provided by the bionic foot spur 7 and the vertical thrust of the torsion spring 10 to achieve directional energy release at the optimal take-off angle of 45°, significantly improving the jumping height and trajectory stability on the soft lunar surface.

[0038] The bottom surface of each bionic toe tip 3 is arranged with a groove-shaped bionic spur 7 which imitates the shape of a jerboa toenail. The conical design is adopted to reduce the insertion resistance. When touching the ground, the three toes are passively unfolded by the impact force and buffered and stored energy through the torsion spring 10. During the power storage stage, the motor pulls the three toes to shrink and aggregate particles to form a dense load-bearing area. When taking off, the curved surface of the bionic spur 7 generates a directional reaction force to achieve an ideal take-off angle of 45°. Ground adaptability is achieved by presetting a 20° toe angle. On hard terrain, the toes are in contact first, and on soft terrain, the sole of the foot is fully under pressure.

Claims

1. A bionic kicking foot for a lunar hopping robot, characterized in that: It includes a sole component (1), three bionic toes (2) and a bionic toe tip (3); The sole component (1) is provided with a leg connecting piece (4) and a plurality of through cavities (6); Each bionic toe (2) is connected to the sole component (1) through a first metatarsophalangeal joint, forming an axisymmetric distribution with an included angle of 20° between adjacent toes. The bionic toe (2) has a bionic toe cavity (9); The end of the bionic toe tip (3) is provided with a bionic foot thorn (7), and the bionic toe tip (3) is connected to the bionic toe (2) through a second metatarsophalangeal joint; A rigid rope (12) passes through the sole cavity (6) and the bionic toe cavity (9). One end of the rigid rope (12) is connected to a leg bouncing mechanism, and the other end of the rigid rope (12) is fixed to a circular rod (8) of the bionic toe tip (3).

2. A bionic jumping foot of a lunar jumping robot according to claim 1, characterized in that: The structure of the first metatarsophalangeal joint is that a first connection hole (5a) of the sole component (1) and a second connection port (5b) of the bionic toe (2) are hinged by a locking screw (11), and torsion springs (10) are symmetrically arranged outside the connection port; The structure of the second metatarsophalangeal joint is that a third connection port (5c) of the bionic toe (2) and a fourth connection hole (5d) of the bionic toe tip (3) are hinged by a locking screw (11), and a torsion spring (10) is configured; 3. The bionic kicking foot of a lunar hopping robot according to claim 1, characterized in that: The bionic foot thorn (7) is a groove-shaped curved surface structure, and its bottom surface is conical; 4. The bionic kicking foot of a lunar hopping robot according to claim 1, characterized in that: The sole component (1), the bionic toe (2) and the bionic toe tip (3) are made of 3D printing PLA material, and the lengths of the three bionic toe tips (3) are equal and the structures are symmetric; 5. The biomimetic kicking leg of a lunar hopping robot according to claim 1, characterized in that: The circular rod (8) of the toe tip (3) is fixedly connected to the end of the rigid rope; 6. The biomimetic jumping foot of a lunar hopping robot according to claim 1, characterized in that: The bionic toe cavity (9) and the sole cavity (6) are coaxially penetrated to provide a movement channel for the rigid rope; 7. The biomimetic kicking leg of a lunar hopping robot according to claim 2, characterized in that: The included angle of the torsion spring (10) of the first metatarsophalangeal joint is 170°, and the included angle of the torsion spring (10) of the second metatarsophalangeal joint is 120° to maintain the natural unfolding posture of the foot end.

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