Variable-stiffness robot leg bone structure based on spring-connecting rod

Abstract

The invention provides a variable stiffness robot leg bone structure based on a spring-connecting rod, which comprises a leg bone-shaped main body, and the leg bone-shaped main body comprises an arc-shaped shell, an end cover and an inner sleeve; the upper end and the lower end of the arc-shaped shell are respectively and fixedly provided with an end cover; the end face, located in the arc-shaped shell, of the end cover is provided with a plurality of sets of bolt hole hinge supports which are symmetrically arranged. The inner sleeves are symmetrically arranged and are embedded in the arc-shaped shell; connecting rods are hinged to the bolt hole hinge supports, the other ends of the connecting rods are hinged to supports at one ends of connecting rings through bolts with holes in the end faces, and supports at the other ends of the connecting rings are hinged to the connecting rods symmetrically arranged on the other side. A clamping ring is hinged to each connecting rod, and a spring is installed between each clamping ring and the corresponding inner sleeve in a positioning mode. And a spring is positioned and mounted between the connecting ring and the inner sleeve. The internal structure of the leg bone is improved, the leg bone has different rigidities when bearing different loads, and meanwhile the structure is light.

Description

Technical Field

[0001] The invention relates to the technical field of vibration reduction structures, and in particular to a variable stiffness robot leg bone structure, and in particular to a variable stiffness robot leg bone structure based on a spring-connecting rod. Background Art

[0002] In the field of robotics, lower limb exoskeleton robots and bionic robots are one of the hot topics of research. These robots usually need to have the ability to walk, run, and jump like humans, and the design of the leg bone structure is the key to achieving these abilities. Traditional robot leg bone structures are often made of rigid materials, which to a certain extent limits the robot's flexibility and adaptability. Variable stiffness robot leg bones can adjust their stiffness in real time according to actual movement needs, thereby adapting to different terrains and gaits. This adaptability makes the robot more natural and smooth in walking, running, jumping and other movements, reducing the movement restrictions caused by rigid leg bones.

[0003] In addition, the lightweight design of leg bones has become a significant trend. The lighter structure can not only effectively improve the flexibility of the robot during movement, but also significantly reduce its energy consumption. The lightweight design reduces the mass of the robot's legs, making the robot more agile and responsive when performing various actions, while also reducing the extra burden caused by weight, thereby extending the robot's endurance and service life.

[0004] Chinese patent CN201910067341.3, publication / announcement date: CN109794926B, a flexible structure with variable stiffness, including a left end cap, a right end cap, a rubber tube, inlaid teeth and a rubber shell. The invention controls the stiffness of the flexible structure with variable stiffness by changing the air pressure to achieve effective control of the degree of adaptability and gripping force when touching the target object. However, the weight of the air pump required to be carried is not taken into account, the device may be bulky, and the use of gas control may cause problems such as leakage. Summary of the invention

[0005] The technical problem to be solved by the present invention is: in view of the deficiencies of the above-mentioned prior art, a variable stiffness robot leg bone structure based on a spring-connecting rod is provided to improve the internal structure of the leg bone so that it has different stiffness when bearing different loads, while making the structure lightweight.

[0006] In order to realize the above technical features, the object of the present invention is achieved as follows: A variable stiffness robot leg bone structure based on a spring-connecting rod comprises a main body in the shape of a leg bone, wherein the main body in the shape of a leg bone comprises an arc-shaped shell, an end cover and an inner sleeve; the upper and lower ends of the arc-shaped shell are respectively fixedly mounted with end covers; The end surface of the end cover located inside the arc-shaped shell is provided with a plurality of groups of symmetrically arranged bolt hole hinge supports; The inner sleeves are arranged symmetrically and embedded in the arc-shaped shell; A connecting rod is hinged on the bolt hole hinge support, the other end of the connecting rod is hinged on a support at one end of the connecting ring through a bolt with a hole on the end surface, and the other end support of the connecting ring is hinged on the connecting rod symmetrically arranged on the other side; A clamping ring is hinged on each connecting rod, and a spring is installed between the clamping ring and the inner sleeve for positioning; Preferably, a spring is positioned and installed between the connecting ring and the inner sleeve.

[0007] Preferably, the main body portion in the shape of a leg bone is hollow inside and can be filled with plastic material.

[0008] Preferably, the end covers are fixedly mounted on both ends of the arc-shaped shell by welding.

[0009] Preferably, the inner sleeve is trumpet-shaped, and the two sets of inner sleeves are symmetrically installed with their mouths facing each other; Preferably, the inner sleeve is in contact with and fits against the inner wall of the arc-shaped shell.

[0010] Preferably, the surface of the inner sleeve is provided with at least four evenly distributed trapezoidal notches.

[0011] Preferably, there are four groups of bolt hole hinge supports, which are symmetrically arranged in four directions of the center of the end cover.

[0012] Preferably, the connecting rod is installed at a certain inclination angle with the center line of the arc-shaped housing; Preferably, there are eight connecting rods in total and they are arranged symmetrically, and every two connecting rods are connected in the middle by a connecting ring, and the whole is spindle-shaped.

[0013] Preferably, one end of the clamping ring is provided with an ear seat for hinged connection with the connecting rod, and the other end is provided with a first spring positioning groove for installing the spring; a second spring positioning groove is provided on the inner wall of the inner sleeve and at a position corresponding to the clamping ring, and the second spring positioning groove and the first spring positioning groove are used for positioning and installing the spring.

[0014] Preferably, hinge seats for hinged connecting rods are respectively provided at both ends of the connecting ring, and a third spring positioning groove is provided in the middle part of the connecting ring; a semicircular spring placement groove is provided on the inner wall of the end of the inner sleeve and at a position corresponding to the connecting ring, and the semicircular spring placement grooves of the two inner sleeves are combined to form a complete fourth spring positioning groove, and the fourth spring positioning groove and the third spring positioning groove are used to position and install the spring.

[0015] Preferably, the connecting rod is a square rod with a uniform cross-section, the rod edge of the square rod adopts a rounded structure, or a round rod with a uniform cross-section.

[0016] The present invention has the following beneficial effects: 1. The present invention adopts light parts such as connecting rods and springs, which can reduce the weight of the structure while ensuring the rigidity of the structure.

[0017] 2. The mechanism of the present invention can be applied to robots in various working environments, and the structure can change its stiffness according to different loads.

[0018] 3. The present invention has extra space inside, which can be filled with other plastic materials. The internal space can make room for the deformation of the connecting rod and the spring, which can improve the internal structure and adjust its rigidity to a certain extent.

[0019] 4. The springs and connecting rods in the present invention can be replaced according to the sizes of different robot leg bones. At the same time, the structure of the present invention can be easily disassembled to facilitate subsequent replacement.

[0020] 5. Compared with some previous shock absorbing and variable stiffness devices, the device of the present invention is compact.

[0021] 6. The structure of the present invention uses a two-stage spring to adjust the stiffness. A stress-strain diagram is available, and the structure of the present invention can adjust its stiffness very well. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0023] Figure 1 It is the overall structure of the present invention.

[0024] Figure 2 It is a schematic diagram of the connecting ring structure of the present invention.

[0025] Figure 3 It is a schematic diagram of the inner sleeve structure of the present invention.

[0026] Figure 4 It is a schematic diagram of the end cover structure of the present invention.

[0027] Figure 5 It is a schematic diagram of the structure of the clamping ring of the present invention.

[0028] In the figure: arc-shaped housing 1, end cover 2, connecting rod 3, clamping ring 4, spring 5, inner sleeve 6, end face bolt with hole 7, connecting ring 8; Bolt hole hinge support 21, first spring positioning groove 41, second spring positioning groove 61, semicircular spring placement groove 62, third spring positioning groove 81. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] Embodiment 1: See also Figure 1-5 A variable stiffness robot leg bone structure based on a spring-connecting rod comprises a main body in the shape of a leg bone, wherein the main body in the shape of a leg bone comprises an arc-shaped shell 1, an end cover 2 and an inner sleeve 6; the upper and lower ends of the arc-shaped shell 1 are respectively fixedly installed with end covers 2; the end surface of the end cover 2 located inside the arc-shaped shell 1 is provided with a plurality of groups of symmetrically arranged bolt hole hinge supports 21; the inner sleeve 6 is symmetrically arranged and embedded in the interior of the arc-shaped shell 1; a connecting rod 3 is hinged on the bolt hole hinge support 21, and the other end of the connecting rod 3 is hinged to one end support of a connecting ring 8 through an end face hole bolt 7, and the other end support of the connecting ring 8 is hinged to the connecting rod 3 symmetrically arranged on the other side; a clamping ring 4 is hinged on each connecting rod 3, and a spring 5 is installed between the clamping ring 4 and the inner sleeve 6 through positioning; a spring 5 is installed between the connecting ring 8 and the inner sleeve 6 for positioning. By adopting the above-mentioned robot leg bone structure, the internal structure of the leg bone is improved, so that it has different stiffness when bearing different loads, and at the same time the structure is made lightweight.

[0034] During the specific working process, the spring 5 located in the middle of the arc-shaped shell 1 constitutes a first-stage spring, and the spring 5 located in the clamping ring 4 and the inner sleeve 6 constitutes a second-stage spring. The connecting rod 3 and the spring 5 can convert the axial force borne by the upper end surface into a radial force, and the buffering of the first-stage spring and the second-stage spring can change its own stiffness, thereby realizing different stiffness when bearing different loads, and making the structure lightweight.

[0035] In this embodiment, in order to facilitate the arrangement of the corresponding spring-connecting rod variable stiffness structure inside the leg bone-shaped body, a hollow structure is adopted inside the leg bone-shaped body part and can be used to fill with plastic material to improve acceptance and impact.

[0036] Furthermore, in this embodiment, in order to ensure the installation stability and reliability of the components inside the arc-shaped housing 1, it is necessary to ensure the installation and fixation reliability of the end caps 2. Based on this, the end caps 2 are fixedly installed at both ends of the arc-shaped housing 1 by welding. The fixed installation reliability of the two is ensured by welding.

[0037] Furthermore, the inner sleeve 6 is trumpet-shaped, and two groups of inner sleeves 6 are symmetrically installed with their mouths facing each other. By adopting the above-mentioned paired installation structure, the subsequent symmetrical arrangement of the internal connecting rods is facilitated.

[0038] Furthermore, the inner sleeve 6 is in contact with and fits the inner wall of the arc-shaped housing 1. The above-mentioned installation structure enhances the installation reliability between the inner sleeve 6 and the arc-shaped housing 1, and effectively prevents the inner sleeve 6 from falling off or shifting.

[0039] Furthermore, at least four evenly distributed trapezoidal notches are formed on the surface of the inner sleeve 6. The use of the trapezoidal notches can reduce the material to a certain extent, thereby reducing the weight of the inner sleeve 6 and improving the performance of the inner sleeve 6 to a certain extent.

[0040] Furthermore, there are four groups of bolt hole hinge supports 21, which are symmetrically arranged in four directions of the center of the end cover 2. Through the above arrangement structure, it is convenient to realize that connecting rods can be installed in four directions respectively.

[0041] Furthermore, the connecting rod 3 is installed at a certain tilt angle to the center line of the arc-shaped shell 1; by adopting a certain tilt angle installation arrangement, it is ensured that it can rotate outward when subjected to force, thereby achieving a good buffering effect.

[0042] Preferably, each of the connecting rods 3 is installed at an angle of 15° to the vertical direction.

[0043] Furthermore, there are eight connecting rods 3 in total, which are arranged symmetrically, and every two connecting rods 3 are connected in the middle by a connecting ring 8, and the whole is spindle-shaped. By adopting the above-mentioned spindle-shaped arrangement structure, it can well adapt to the structure of the arc-shaped shell 1, and is arranged just opposite to the size of the arc-shaped shell 1, so as to enhance the strength of the leg bone structure of the robot to a certain extent.

[0044] In this embodiment, in order to realize reliable positioning of the spring 5 between the clamping ring 4 and the inner sleeve 6 and prevent it from falling off, a corresponding positioning structure is designed. Based on this, one end of the clamping ring 4 is provided with an ear seat for hinged connection with the connecting rod 3, and the other end is provided with a first spring positioning groove 41 for installing the spring 5; a second spring positioning groove 61 is provided on the inner wall of the inner sleeve 6 and at a position corresponding to the clamping ring 4, and the second spring positioning groove 61 and the first spring positioning groove 41 are used for positioning and installing the spring 5.

[0045] The above structure ensures that both ends of the spring 5 can be reliably positioned on the second spring positioning groove 61 and the first spring positioning groove 41 , so that the spring 5 will not fall off during the swinging of the connecting rod to compress the spring 5 .

[0046] Furthermore, in order to ensure the buffering effect of the spring 5 , in this embodiment, the clamping ring 4 is installed at one third of the length of the connecting rod 3 .

[0047] Similarly, in this embodiment, in order to realize the reliable positioning of the spring 5 between the connecting ring 8 and the inner sleeve 6 and prevent it from falling off, a corresponding positioning structure is designed. Based on this, the two ends of the connecting ring 8 are respectively provided with hinge seats for hinged connecting rod 3, and a third spring positioning groove 81 is provided in the middle of the connecting ring 8; a semicircular spring placement groove 62 is provided on the inner wall of the end of the inner sleeve 6 and at a position corresponding to the connecting ring 8, and the semicircular spring placement grooves 62 of the two inner sleeves 6 are combined to form a complete fourth spring positioning groove, and the fourth spring positioning groove and the third spring positioning groove 81 are used for positioning and installing the spring 5.

[0048] The above structure ensures that both ends of the spring 5 can be reliably positioned on the fourth spring positioning groove and the third spring positioning groove 81, so that the spring 5 will not fall off during the swinging of the connecting rod to compress the spring 5.

[0049] In this embodiment, in order to reduce costs and simplify the processing of the connecting rod, the connecting rod 3 is a square rod with a uniform cross-section, and the rod edge of the square rod adopts a rounded structure, or a round rod with a uniform cross-section is adopted. Through the above connecting rod 3, the processing cost is greatly reduced in the specific manufacturing process.

[0050] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A variable stiffness robot leg bone structure based on spring-connecting rod, characterized in that: It comprises a main body in the shape of a leg bone, the main body in the shape of a leg bone comprising an arc-shaped shell (1), an end cover (2) and an inner sleeve (6); the end covers (2) are fixedly mounted on the upper and lower ends of the arc-shaped shell (1); The end surface of the end cover (2) located inside the arc-shaped housing (1) is provided with a plurality of groups of symmetrically arranged bolt hole hinge supports (21); The inner sleeves (6) are symmetrically arranged and embedded in the interior of the arc-shaped housing (1); A connecting rod (3) is hinged on the bolt hole hinge support (21), the other end of the connecting rod (3) is hinged to a support at one end of a connecting ring (8) through a bolt (7) with an end face hole, and the other end support of the connecting ring (8) is hinged to a connecting rod (3) symmetrically arranged on the other side; A clamping ring (4) is hingedly connected to each connecting rod (3), and a spring (5) is installed between the clamping ring (4) and the inner sleeve (6) for positioning; A spring (5) is positioned and installed between the connecting ring (8) and the inner sleeve (6).

2. The variable stiffness robot leg bone structure based on spring-connecting rod according to claim 1, characterized in that: The main body part in the shape of a leg bone is hollow inside and can be filled with plastic material.

3. The variable stiffness robot leg bone structure based on spring-connecting rod according to claim 1, characterized in that: The end covers (2) are fixedly mounted on the two ends of the arc-shaped housing (1) by means of a welding process.

4. The variable stiffness robot leg bone structure based on spring-connecting rod according to claim 1, characterized in that: The inner sleeve (6) is trumpet-shaped, and the two sets of inner sleeves (6) are symmetrically installed with their mouths facing each other. The inner sleeve (6) is in contact with and fits the inner wall of the arc-shaped shell (1).

5. The variable stiffness robot leg bone structure based on spring-connecting rod according to claim 1, characterized in that: The surface of the inner sleeve (6) is provided with at least four evenly distributed trapezoidal notches.

6. The variable stiffness robot leg bone structure based on spring-connecting rod according to claim 1, characterized in that: There are four groups of bolt hole hinge supports (21) which are symmetrically arranged in four directions at the center of the end cover (2).

7. The variable stiffness robot leg bone structure based on spring-connecting rod according to claim 1, characterized in that: The connecting rod (3) is installed at a certain inclination angle with respect to the center line of the arc-shaped housing (1); There are eight connecting rods (3) in total and they are arranged symmetrically. Every two connecting rods (3) are connected in the middle by a connecting ring (8), and the whole is in a spindle shape.

8. The variable stiffness robot leg bone structure based on spring-connecting rod according to claim 1, characterized in that: One end of the clamping ring (4) is provided with an ear seat for being hinged to the connecting rod (3), and the other end is provided with a first spring positioning groove (41) for installing the spring (5); A second spring positioning groove (61) is provided on the inner wall of the inner sleeve (6) at a position corresponding to the clamping ring (4), and the second spring positioning groove (61) and the first spring positioning groove (41) are used for positioning and installing the spring (5).

9. The variable stiffness robot leg bone structure based on spring-connecting rod according to claim 1, characterized in that: Both ends of the connecting ring (8) are respectively provided with hinge seats for hingedly connecting the connecting rod (3), and a third spring positioning groove (81) is provided in the middle of the connecting ring (8); A semicircular spring placement groove (62) is provided on the inner wall of the end of the inner sleeve (6) at a position corresponding to the connecting ring (8); the semicircular spring placement grooves (62) of the two inner sleeves (6) are combined to form a complete fourth spring positioning groove; the fourth spring positioning groove and the third spring positioning groove (81) are used to position and install the spring (5).

10. The variable stiffness robot leg bone structure based on spring-connecting rod according to claim 1, characterized in that: The connecting rod (3) is a square rod with a uniform cross-section, the rod edge of the square rod adopts a rounded structure, or adopts a round rod with a uniform cross-section.

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