CN115892283A - Foot structure of humanoid robot passively adapting to uneven ground - Google Patents

Abstract

The invention relates to a foot structure of a humanoid robot passively adapted to uneven ground, which is divided into a half sole part and a waist heel part: three toes are arranged at one end of the half sole part, and each toe is connected with the metatarsal bone through a two-degree-of-freedom elastic assembly; the metatarsus at the other end is rotatably connected with the scaphoid through a second connecting shaft and two torsional springs; the scaphoid and the heel bone of the lumbar heel part are rotatably connected through a third connecting shaft and two torsion springs to form a first part of the arch structure; the long plantar ligament is connected with the scaphoid and the heel bone through two elastic elements respectively to form a second part of the arch structure. This foot structure adopts the syllogic design, and in the robot motion process, the foot plays the cushioning effect when receiving ground effort through a plurality of torsional springs and the passive adjustment foot gesture of elastic element, realizes improving flexibility, the stability and the environmental adaptability of humanoid robot foot to the self-adaptation on uneven ground.

Description

Foot structure of humanoid robot passively adapting to uneven ground

Technical Field

The invention relates to the technical field of humanoid robots, in particular to a foot structure of a humanoid robot passively adaptive to uneven ground.

Background

With the continuous expansion of the expected application scenarios of humanoid robots, such as cargo handling, personal assistance and nursing, space exploration, disaster area search and rescue, etc., humanoid robots have become one of the hot directions in the contemporary research field. Due to the continuous development of the times, the working environment of the humanoid robot is more complicated, which has higher requirements on the structure of the robot. The foot of the humanoid robot, which is the only part in contact with the ground, needs to be operated in a complex environment, and has excellent environmental adaptability, so the design of the humanoid robot is particularly important. The structural characteristics of the human foot are analyzed, and the bionics is one of breakthrough points for improving the foot walking capability of the humanoid robot.

In the prior art, the foot structure of the humanoid robot is designed in two main forms: one is a flat plate structure, the structure lacks buffer and shock absorption effects, and the straight form forcibly restricts the foot falling mode, so that the robot is easy to fall down due to uncertainty of a walking road surface in a complex environment; the other is a two-section structure, usually a two-section structure of toes and a sole, or a two-section structure of a front sole and a rear sole, the former has a small difference from a flat plate structure, and the latter has poor motion flexibility due to the limitation of freedom degree, so that point contact or line contact is easily formed when the foot contacts uneven ground, and the walking motion of the humanoid robot is not facilitated.

Disclosure of Invention

The invention provides a foot structure of a humanoid robot passively adaptive to uneven ground, wherein toes and metatarsals are connected through a two-degree-of-freedom elastic assembly, the front end of the foot can be adaptive to the uneven ground, and the contact point of a sole and the ground is increased, so that the walking stability of the robot is improved; the foot can be passively and slightly expanded when being impacted by the ground through connecting all parts of the arch-imitating structure through a plurality of torsional springs, so that the cushioning effect is realized; through syllogic structural design, the robot realizes the bionical behavior mode when the people foot touches to the ground in the walking process, and need not to keep sole and holding surface parallel for guaranteeing stability initiative.

In order to achieve the purpose, the technical scheme provided by the invention is as follows: a humanoid robot foot structure for passive adaptation to non-level ground, the foot structure comprising a forefoot component and a heel component:

one end of the half sole part is provided with three toes, and each toe is connected with the metatarsal bone through a two-degree-of-freedom elastic assembly; the metatarsal bones are rotatably connected with the scaphoid through a second connecting shaft and two torsional springs;

the two-degree-of-freedom elastic assembly comprises a central connecting piece with four shaft rods, incomplete gears arranged on the front side and the rear side of the central connecting piece, torsion springs arranged on the four shaft rods of the central connecting piece, two first connecting shafts, four fixed connecting pieces and four complete gears;

two incomplete gears are respectively arranged on each side of the front side and the rear side of the central connecting piece, the incomplete gears on different sides are mutually vertical, and the incomplete gears on the same side are mutually parallel; each incomplete gear is meshed with a complete gear, two complete gears on the same side are mounted on a first connecting shaft, two ends of the first connecting shaft are rotatably connected with one end of a fixed connecting piece, and the other end of the fixed connecting piece is mounted on a central connecting piece shaft lever through a torsion spring; the toes and the metatarsals are respectively and fixedly connected with a group of fixed connecting pieces in the two-degree-of-freedom elastic assembly;

the heel part of the waist comprises a scaphoid, a heel bone and a long sole ligament, and the scaphoid and the heel bone are rotatably connected through a third connecting shaft and two torsion springs to form a first part of an arch structure; two ends of the long sole ligament are respectively connected with the scaphoid and the heel bone through two elastic elements to form a second part of the arch structure.

Furthermore, the non-complete gear and the fixed connecting piece are provided with bulges, and two ends of the torsion spring are respectively contacted with the bulges of the non-complete gear and the fixed connecting piece.

Furthermore, the toe can realize passive self-adaptive adjustment under the action of the radial torsion of the torsion spring when stressed, and can be restored to a natural state under the condition of no stress.

Furthermore, the front ends of the toes are hemispheroids, and the rear ends of the metatarsals, which are in contact with the ground, are rounded corners; the toes and the metatarsals are hollow structures, and a plurality of grooves are cut on the surface connected with the fixed connecting piece so as to allow the complete gear in the two-freedom-degree elastic assembly to rotate.

Furthermore, two bosses are arranged on the upper end surface of the metatarsus, holes are drilled on the bosses respectively, the bosses are rotatably connected with the second connecting shaft, and the bosses are rotatably connected with the scaphoid through the second connecting shaft, the two torsion springs; the inner sides of the two bosses and the two sides of the scaphoid are provided with bulges for limiting the position of the torsion spring.

Furthermore, the scaphoid and the heel bone form rotatable connection through a third connecting shaft and two torsion springs, a drilling hole in the front side of the upper end forms rotatable connection with the third connecting shaft, the front part and the rear part of the bottom end in contact with the ground are rounded corners, and protrusions are arranged on the inner side of the heel bone and two sides of the scaphoid and used for limiting the positions of the torsion springs; the radial torsion action of the torsion spring enables the scaphoid and the heel bone to slide outwards when the arch of the foot is contacted by the contact force of the contact surface.

Furthermore, bosses are arranged in the middle of the scaphoid and the heel bone, holes are drilled on the bosses, and the long pelma ligament and the pelma keep parallel in a natural state by connecting the two elastic elements with the two drilled bosses on the long pelma ligament; the long plantar ligament has certain toughness, and the elastic element and the long plantar ligament are driven by the scaphoid and the heel bone to jointly bear the ground impact force, so that the buffer effect is achieved in the walking process of the robot.

The invention has the following beneficial effects:

the structural design of the two-degree-of-freedom elastic assembly enables each toe to have two degrees of freedom, can passively adapt to the surface topography of uneven ground, increases the contact points of the soles and the ground, improves the walking stability of the humanoid robot, and enables the toes to return to an initial natural state before the toes touch the ground next time under the radial torsion action of the limiting torsion spring.

When the heel part of the waist part slides to two sides in the scaphoid and the heel bone through the torsion spring, the elastic element and the long ligament of the sole, the heel part of the waist part shares and eliminates the impact force from the ground on the foot, and simulates the buffering effect generated by the stress expansion of the foot arch when a person actually walks.

The whole foot structure is not provided with a driving mechanism, so that part of calculation links in the walking process of the robot are eliminated, and energy required by the driving mechanism during working is saved.

The foot structure can be divided into three sections according to the contact surface with the ground, so that the foot structure of the humanoid robot is closer to the actual human foot, and the flexibility provided by the bionic design improves the adaptability of the robot to the complex environment.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment of the present invention;

FIG. 2 is a side view of an embodiment of the present invention;

FIG. 3 is a top view of an embodiment of the present invention;

FIG. 4 is a bottom view of an embodiment of the present invention;

FIG. 5 is a schematic view of a toe and two degree of freedom elastomeric assembly of an embodiment of the present invention;

FIG. 6 is a schematic view of a two degree-of-freedom elastomeric assembly portion assembly in accordance with an embodiment of the present invention;

FIG. 7 is a schematic view of a two degree-of-freedom elastomeric assembly portion assembly in accordance with an embodiment of the present invention;

fig. 8 is a schematic illustration of a heel assembly construction according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

The human foot can be divided into three major parts: heel, lumbar and forefoot. The root is responsible for directly bearing most of the body weight; the waist is responsible for connecting the half sole and the heel and transferring the weight of the body part to the half sole; the front palm part has the functions of bearing weight, adapting to the ground and balancing the body.

The invention provides a foot structure of a humanoid robot passively adapting to uneven ground by referring to the foot structure of a human body from a bionic angle, which comprises the following components:

the sole component is characterized by comprising a forefoot component, wherein three toes 1 are arranged at one end of the forefoot component, and each toe 1 is connected with a metatarsal bone 3 through a two-degree-of-freedom elastic assembly 2; the metatarsal 3 is rotatably connected to the navicular 502 by a second connecting shaft 401 and two torsion springs 402.

A lumbar heel part, the navicular 502 and the heel bone 501 are rotatably connected through a third connecting shaft 503 and two torsion springs 504 to form a first part of the arch structure; the long plantar ligament 505 is connected to the navicular 502 and the heel bone 501 via two elastic elements 506, respectively, constituting a second part of the arch structure.

As shown in fig. 1, 2, 3 and 4, the foot structure of the humanoid robot passively adapting to uneven ground connects three toes 1 to the same metatarsal bone 3 through three two-degree-of-freedom elastic assemblies 2. As shown in fig. 5, 6 and 7, the two-degree-of-freedom elastic assembly 2 includes one central link 201, four non-complete gears 202, four torsion springs 203, two first connecting shafts 204, four fixed links 205 and four complete gears 206.

The two-degree-of-freedom elastic assembly 2 includes a center link 201 having four shafts, non-complete gears 202 installed on both front and rear sides of the center link 201, torsion springs 203 installed on the four shafts of the center link 201, and two first connection shafts 207, four fixed links 205, and four complete gears 206. Two incomplete gears 202 are respectively arranged on each side of the front and the back of the central connecting piece 201, the incomplete gears 202 on different sides are perpendicular to each other, and the incomplete gears 202 on the same side are parallel to each other. Each non-complete gear 202 is engaged with a complete gear 206, and two complete gears 206 on the same side are mounted on a first connecting shaft 207, and both ends of the first connecting shaft 207 are rotatably connected with one end of a fixed connecting piece 205, and the other end of the fixed connecting piece 205 is mounted on a shaft rod of the central connecting piece 201 through a torsion spring 203. The toes 1 and the metatarsals 3 are fixedly connected to a set of fixed links 205 in the two-degree-of-freedom elastic assembly 2, respectively. The incomplete gear 202 and the fixed connecting piece 205 are provided with bulges, and two ends of the torsion spring 203 are respectively contacted with the bulges of the incomplete gear 202 and the fixed connecting piece 205. The toes 1 and the metatarsals 3 are respectively and fixedly connected with a group of fixed connecting pieces 205 in the two-degree-of-freedom elastic assembly 2, the front ends of the toes 1 are hemispheroids, and the rear ends of the metatarsals 3 contacting with the ground are round corners. The toes 1 and the metatarsals 3 are hollow structures, and the faces connected with the fixed connecting pieces 205 are cut with grooves for allowing the complete gear 206 in the two-degree-of-freedom elastic assembly 2 to rotate. Due to the characteristic of the two-degree-of-freedom elastic assembly 2, the toes 1 can passively adapt to uneven ground, contact points between the soles and the ground are increased, and the stability of the feet is improved. The upper end face of the metatarsal bone 3 is provided with two bosses, which are drilled with holes respectively and are rotatably connected with the second connecting shaft 401, and are rotatably connected with the scaphoid 502 through the second connecting shaft 401 and the two torsion springs 402. Protrusions are provided on the inner sides of the two bosses and on both sides of the navicular 502 to limit the position of the torsion spring 402. The structural characteristics of the two-degree-of-freedom elastic element 2 enable each toe 1 to have two degrees of freedom, when the toe 1 touches the ground in the walking process, the toe can be self-adaptive to uneven ground, and when the toe leaves the ground, the toe automatically restores to the initial state due to the radial torsion action of the torsion spring 203.

As shown in fig. 8, the metatarsal 3 is rotatably connected to the navicular 502 by the torsion spring assembly 4, and the torsion spring assembly 4 allows the rotation of the lumbar heel part relative to the forefoot part about the second connecting shaft 401, thereby realizing the flexibility of the foot structure. In order to support the entire body weight, the bottom of the foot is arched, and the heel part of the waist in the embodiment has two arched structures, namely a scaphoid 502 and a heel bone 501, and a long plantar ligament 505. Wherein, the scaphoid 502 and the heel bone 501 are rotatably connected with two torsion springs 504 through a third connecting shaft, the heel bone 501 is designed to be 7-shaped when viewed from the side, a drilling hole at the front side of the upper end is rotatably connected with the third connecting shaft 503, and the inner side of the heel bone 501 and two sides of the scaphoid 502 are provided with protrusions for limiting the position of the torsion springs 504; the long plantar ligament 505 is connected with the drilling bosses on the scaphoid 502 and the heel bone 501 respectively through an elastic element 506 in front and at the back, so that the long plantar ligament 505 and the sole are kept in a parallel state in a natural state. When the sole of the foot is contacted with the contact force from the ground, the heel bone 501 and the navicular bone 502 slide outwards, at the same time, the navicular bone 502 and the metatarsal bone 3 relatively rotate around the torsion spring assembly 4, the long ligament 505 of the sole of the foot and the elastic element 506 share the impact force of the ground together, and the shock absorption effect is achieved during the contact process of the robot with the ground.

From the motion perspective of a single leg of the robot during walking, the human body trunk moves forwards and can be regarded as that the supporting leg moves backwards relative to the human body trunk, the heel, namely the heel bone 501, of the foot with the tail end in the state of maximum contact area with the ground is lifted along with the inclination of the supporting leg, and the scaphoid 502 drives the heel bone 501 to rotate relative to the metatarsal bone 3 under the action of the torsion spring assembly 4. Due to the characteristics of the two-degree-of-freedom elastic assembly 2, the metatarsal 3 rotates with respect to the toe 1. In the whole foot lifting process, the foot is divided into three sections, namely a toe section, a metatarsal section and a heel section, which leave the ground in sequence. After leaving the ground, the supporting legs are changed into swinging legs, and all parts of the feet are restored to natural states under the action of radial torsion of a plurality of torsion springs. When the swing leg is converted into the support leg again, the heel bone 501 touches the ground first, and at this time, the toes 1, the metatarsals 3, and the navicular 502 are in a natural state before touching the ground. On a flat ground, the toes 1 and the metatarsals 3 rotate around the contact point of the heel bone 501 and the ground as a rotation center along with the foot and touch the ground at the same time, at the moment, under the action of the ground contact force, the heel bone 501 and the scaphoid 502 slide in the front-back direction, the scaphoid 502 pushes the half sole component to move in the sliding process, the torsion spring 504 is driven by the heel bone 501 to bear force, and meanwhile, the elastic element 506 and the long sole ligament 505 are pulled to jointly buffer the impact force. On uneven ground, the toes 1 and the metatarsals 3 may not touch the ground simultaneously according to the actual terrain of the ground, and the toes 1 passively adjust the posture to adapt to the ground due to the two degrees of freedom and the elastic characteristic of the two-degree-of-freedom elastic assembly 2, so that the contact points of the feet and the ground are increased, and the stability of the feet is improved; in addition, as in the case of a flat ground, the torsion spring 504, the elastic member 506, and the long plantar ligament 505 play a role in cushioning during contact of the foot with the ground.

According to the description of the embodiment, the foot structures of the three sections of the robot are passively and adaptively adjusted to be in contact with uneven ground, impact force from the ground is born by the torsion springs and the elastic elements, the buffer effect is achieved in the walking process of the robot, the stability and flexibility of the robot motion are improved, the walking capability of the humanoid robot is obviously enhanced, and the method has important significance for carrying out experiments on the robot.

In summary, the above-mentioned process is only an embodiment of the present invention, and is not intended to limit the application scope of the present invention. The nomenclature used herein is for better describing the structural ontology and does not exclude the possibility of using other terms, it should be understood that any modification, substitution, etc. within the scope of the design principle and structural design of the present invention are within the scope of the present invention.

Claims (7)

1. A humanoid robot foot structure passively adapting to uneven ground, characterized in that the foot structure comprises a forefoot part and a heel part:

three toes (1) are arranged at one end of the half sole part, and each toe (1) is connected with the metatarsal bone (3) through a two-degree-of-freedom elastic assembly (2); the metatarsal bone (3) is rotatably connected with the scaphoid (502) through a second connecting shaft (401) and two torsion springs (402);

the two-degree-of-freedom elastic assembly (2) comprises a central connecting piece (201) with four shaft rods, incomplete gears (202) arranged on the front side and the rear side of the central connecting piece (201), torsion springs (203) arranged on the four shaft rods of the central connecting piece (201), two first connecting shafts (204), four fixed connecting pieces (205) and four complete gears (206);

two incomplete gears (202) are respectively arranged on the front side and the rear side of the central connecting piece (201), the incomplete gears (202) on different sides are mutually vertical, and the incomplete gears (202) on the same side are mutually parallel; each non-complete gear (202) is meshed with a complete gear (206), two complete gears (206) on the same side are mounted on a first connecting shaft (204), two ends of the first connecting shaft (204) are rotatably connected with one end of a fixed connecting piece (205), and the other end of the fixed connecting piece (205) is mounted on a shaft lever of a central connecting piece (201) through a torsion spring (203); the toes (1) and the metatarsals (3) are respectively and fixedly connected with a group of fixed connecting pieces (205) in the two-degree-of-freedom elastic assembly (2);

the heel part comprises a scaphoid (502), a heel bone (501) and a long plantar ligament (505), wherein the scaphoid (502) and the heel bone (501) form a rotatable connection through a third connecting shaft (503) and two torsion springs (504) to form a first part of an arch structure; the two ends of the long plantar ligament (505) are respectively connected with the scaphoid (502) and the heel bone (501) through two elastic elements (506) to form a second part of the arch structure.

2. The foot structure of the humanoid robot passively adapted to uneven ground as claimed in claim 1, wherein the incomplete gear (202) and the fixed connecting member (205) are provided with protrusions, and both ends of the torsion spring (203) respectively contact with the protrusions of the incomplete gear (202) and the fixed connecting member (205).

3. The foot structure of the humanoid robot passively adapting to the uneven ground as claimed in claim 1, characterized in that the radial torsion action of the torsion spring (203) enables the toes (1) to realize passive adaptive adjustment when being stressed and to return to the natural state when not being stressed.

4. The foot structure of the humanoid robot passively adapting to the uneven ground as claimed in claim 1, characterized in that the front end of the toes (1) is a hemisphere, and the rear end of the metatarsal bones (3) contacting with the ground is a round angle; the toes (1) and the metatarsals (3) are hollow structures, and the surface connected with the fixed connecting piece (205) is cut with a plurality of grooves for allowing the complete gear (206) in the two-degree-of-freedom elastic assembly (2) to rotate.

5. The foot structure of the humanoid robot for passively adapting to uneven ground as claimed in claim 1, wherein the metatarsal bones (3) are provided with two bosses, which are drilled on the upper end surface thereof and are rotatably connected with the second connecting shaft (401) through the second connecting shaft (401), the two torsion springs (402) and the navicular bones (502); the inner sides of the two bosses and the two sides of the scaphoid (502) are provided with bulges used for limiting the position of the torsion spring (402).

6. The foot structure of the humanoid robot passively adaptable to uneven ground as claimed in claim 1, wherein the navicular bone (502) and the heel bone (501) are rotatably connected with two torsion springs (504) through a third connecting shaft, the upper front side drilling hole is rotatably connected with the third connecting shaft (503), the bottom end contacting with the ground is rounded in front and back, and the inner side of the heel bone (501) and the two sides of the navicular bone (502) are provided with protrusions for limiting the positions of the torsion springs (504); the radial torsion action of the torsion spring (504) enables the scaphoid (502) and the heel bone (501) to slide outwards when the arch of the foot is contacted by the contact surface.

7. The foot structure of the humanoid robot for passively adapting to uneven ground as claimed in claim 1, wherein the navicular bone (502) and the heel bone (501) are provided with bosses in the middle part, holes are drilled on the bosses, and the long plantar ligament (505) is kept in parallel with the sole in a natural state through connecting two elastic elements (506) with the two drilled bosses on the long plantar ligament (505); the long plantar ligament (505) has certain toughness, and the elastic element (506) and the long plantar ligament (505) are driven by the scaphoid (502) and the heel bone (501) to jointly bear the ground impact force, so that the buffer effect is achieved in the walking process of the robot.

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