Single-degree-of-freedom multi-connecting-rod mechanism for foot type robot

Abstract

The single-degree-of-freedom multi-connecting-rod mechanism of the foot type robot comprises a frame body, a telescopic joint driving part and a movable function part, and a plurality of connecting shafts and a plurality of connecting rods are arranged in the frame body in parallel; the fixed end part of the telescopic joint driving piece is sleeved on the first connecting shaft and can swing around the axis of the first connecting shaft, and the movable end part of the telescopic joint driving piece is respectively hinged with one end of the first connecting rod and one end of the second connecting rod through a second hinge shaft; the other end of the first connecting rod is hinged to one end of the third connecting rod; the movable functional part is fixedly connected with the third connecting rod and can swing around the axis of the third connecting shaft along with the third connecting rod when the movable end of the telescopic joint driving part stretches out and draws back. According to the single-degree-of-freedom multi-connecting-rod mechanism, the power of the driving piece is dispersed to the connecting shafts through the connecting rods through the multiple hinge points, the loading force is borne by the connecting rods and the connecting shafts together, and compared with a traditional mode that a single joint is used for supporting the force of a rotating joint part, the single-degree-of-freedom multi-connecting-rod mechanism can be higher in bearing capacity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of robot technology, and particularly relates to a single-degree-of-freedom multi-link mechanism of a foot-type robot. BACKGROUND

[0002] In the field of robot technology, a multi-link mechanism is a core basic component for supporting a robot to complete joint movement, realize force transmission, and accurately control a posture, and its application scenarios widely cover multiple key fields: in a bionic foot-type robot, it is used for driving transmission of a knee and a hip; in an industrial carrying robot, it bears a power transmission function of an end effector; and in a medical precision robot field, it is a key support for realizing a flexible operation of a joint of a minimally invasive surgical instrument. In the prior art, a multi-link mechanism scheme for robot joint driving mostly adopts a serial multi-link structure, a single driven joint is driven by a motor to move a subsequent link, a hinge relationship between the links is utilized to realize bending and stretching of a robot joint, and thus the number of links is simplified to reduce the difficulty of motion solving. However, the above prior art scheme still has obvious deficiencies, for example, the serial transmission structure causes errors to be superimposed with the number of links, in a precision assembly, a minimally invasive operation, and the like, cumulative errors generated by an end execution component are difficult to meet the demand of high-precision operation, and in addition, load forces are concentrated on a single point of a driven joint, a single joint needs to bear external forces of the entire transmission chain, and under heavy load, the joint is prone to deformation, motion jamming, and the like. SUMMARY

[0003] In view of the deficiencies in the prior art, the single-degree-of-freedom multi-link mechanism for a foot-type robot disclosed by the present application comprises: a frame body, which has a first connecting shaft, a second connecting shaft, and a third connecting shaft arranged in parallel inside, and a first link, a second link, and a third link; a telescopic joint driving member arranged in the frame body, which has a fixed end and a movable end capable of telescopic movement relative to the fixed end, the fixed end is sleeved on the first connecting shaft and can swing around the first connecting shaft axis, the movable end is hingedly connected with one end of the first link and one end of the second link through a second hinge shaft, the other end of the first link is hingedly connected with one end of the third link through a first hinge shaft, the other end of the second link is connected with the second connecting shaft and can swing around the second connecting shaft axis, the other end of the third link is connected with the third connecting shaft and can swing around the third connecting shaft axis, and the second connecting shaft is located between the first connecting shaft and the third connecting shaft in the frame body; a movable functional member, which is fixedly connected with the third link and can swing around the third connecting shaft axis when the third link performs telescopic movement at the movable end of the telescopic joint driving member.

[0004] Preferably, the other end of the second connecting rod is sleeved on the second connecting shaft and rotates around the second connecting shaft, and the other end of the third connecting rod is sleeved on the third connecting shaft and can rotate around the third connecting shaft; the movable end of the telescopic joint drive component can rotate around the same axis as one end of the first connecting rod and one end of the second connecting rod. The movable functional component is fixedly connected to the bushing end of the other end of the third link, and the movable functional component is bent at a fixed angle relative to the third link body.

[0005] Preferably, one end of the second link and one end of the third link both extend toward the same side of the frame and are respectively hinged to both ends of the first link.

[0006] Preferably, the single-degree-of-freedom multi-link mechanism is used in the leg component, and the movable functional component is used to drive the movable functional component to rotate relative to the thigh component; or The single-degree-of-freedom multi-link mechanism is used in the arm component, and the movable functional component is used to drive the forearm component to rotate relative to the upper arm component.

[0007] Preferably, the telescopic joint drive is a linear electric drive joint module or a hydraulic cylinder.

[0008] Preferably, the telescopic length of the telescopic joint drive is configured to be determined based on the correspondence between the target rotation angle and the length of the telescopic joint drive obtained through pre-calculation, and the target rotation angle to be achieved; the target rotation angle is the angle formed by the swing of the movable functional component around the third shaft axis and the set reference datum plane.

[0009] Preferably, the target rotation angle β and the length of the telescopic joint drive component are obtained through pre-calculation. l The correspondence is as follows: ,in l BD The rod length should be a positive value. ; This involves transforming a single-degree-of-freedom multi-link mechanism into a corresponding geometrically simplified analysis model. l 1 represents the length of the geometrically simplified feature AB of the telescopic joint drive component. l 6 represents the length of AE between the first simplified point A and the second simplified point E of the coupling axis. l 2 represents the BE length between the first simplified hinge point B and the second simplified coupling point E. l 3 represents the length BC between the second simplified hinge point C and the first simplified hinge point B. l 4 represents the length of CD between the simplified point D of the third coupling and the simplified point C of the second hinge. l 5 represents the length of DE between the simplified point D of the third axis and the simplified point E of the second axis, and the target rotation angle β is the angle between CD and the horizontal straight line.

[0010] Preferably, the relationship between the target rotation angle and the length of the telescopic joint drive component is obtained through pre-calculation using the following steps: Obtain the parameters of each component of the single-degree-of-freedom multi-link mechanism; the component parameters include the corresponding lengths of the first link, the second link, and the third link, the distance between the axis of the first link and the axis of the second link, the distance between the axis of the second link and the axis of the third link, and the fixed angle parameters of each link position; define the physical characteristics of the target rotation angle to be analyzed, which is subject to the length adjustment of the telescopic joint drive component; A geometric simplification analysis model is constructed for the single-degree-of-freedom multi-link mechanism. The geometric simplification analysis model is a feature geometric figure that simplifies each connecting shaft and each hinge node to a point and each link to a straight line connecting two points. Through the topological relationship between the geometric figures, a framework for the association between the length and angle parameters of each component is constructed. Applying the law of cosines to the feature geometry, the correspondence between the length of each link and the target rotation angle, and the correspondence between the length of each link and the length of the telescopic joint drive component are derived sequentially, forming a two-level parameter mapping chain; combining the above two-level parameter mapping relationships, the direct correspondence between the length of the drive component and the target rotation angle is obtained.

[0011] Preferably, the geometrically simplified analysis model is established with the third shaft axis of the mechanism as the origin of the reference coordinate system, and the fixed angle parameters of each link position include the initial angle formed by the line connecting the second and third shafts and the reference coordinate system. For each characteristic triangle in the geometrically simplified analysis model, a relationship is established between the square of the side length and the cosine of the two sides and the included angle. The key link length includes the length of the transition link connecting the drive component and the execution component. In the two-level parameter mapping chain, the first level mapping is a function relationship between the length of each link and the target rotation angle, and the second level mapping is a function relationship between the length of each link and the length of the drive component.

[0012] Preferably, the steps for calculating and obtaining the correspondence between the target rotation angle and the length of the telescopic joint drive component are as follows: A simplified geometric analysis model of the single-degree-of-freedom multi-link mechanism is constructed, and a framework relating the lengths and angles of each component is established. The simplified geometric feature of the telescopic joint drive component is transformed into a length AB of... l 1. The length of AE between the first simplified point A and the second simplified point E of the coupling axis is: l 6. The length of BE between the simplified first hinge point B and point E is... l 2. The length of BC between the simplified second hinge point C and point B is: l 3. The simplified length of CD between point D and point C in the third axis is... l4. The length of DE between points D and E is l5, where the angle between CD and the horizontal line is β; Construct triangles BED and BDC: Applying the Law of Cosines: , ; Calculation yielded: ; ; Substitute ∠EDB and ∠BDC into the formula The calculation yielded: ; In triangle BEA, applying the Law of Cosines: ; Calculation obtained ; ; Then it can be deduced that: ; In triangle BED, applying the law of cosines: , bring in The calculation yielded: ; Received l BD With fixed rod length l 1. l 2. l 5. l The relationship between 6 and ∠AED was used to obtain the rod length in the mechanism after conversion. l 1 The relationship between the parameters and ∠GDC; ultimately, the length of the telescopic joint drive component is obtained. l 1 The parameter relationship with the rotation angle β of the moving functional component: ,in l BD The rod length should be a positive value. .

[0013] This invention discloses a single-degree-of-freedom multi-link mechanism for a legged robot. Through multiple hinge points, the driving force is distributed from the first and second links to the second and third shafts. The load is shared by multiple links and shafts, rather than by a single joint. This distributes the force across multiple links, resulting in a stronger load-bearing capacity and greater load capacity compared to traditional mechanisms where a single joint supports the force at rotating joints. It solves the problem in existing serial structures where the load is concentrated on a single active joint, leading to deformation, jamming, and insufficient load-bearing capacity.

[0014] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings. In the following description, the same reference numerals denote the same parts.

[0017] Figure 1 This is a schematic diagram of a single-degree-of-freedom multi-link mechanism disclosed in an embodiment of this application.

[0018] Figures 2-3 This is a schematic diagram showing a variation of a single-degree-of-freedom multi-link mechanism disclosed in an embodiment of this application.

[0019] Figure 4 This is a schematic diagram of a geometrically simplified analysis model disclosed in an embodiment of this application.

[0020] Figures 5-6 This is a simplified schematic diagram illustrating a single-degree-of-freedom multi-link mechanism disclosed in an embodiment of this application.

[0021] Figure 7 This is a schematic diagram showing the relationship between the target rotation angle and the length of the telescopic joint drive component disclosed in an embodiment of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a limitation of quantity, but rather indicate the presence of at least one.

[0026] In this embodiment, as Figure 1 As shown, a single-degree-of-freedom multi-link mechanism for a legged robot is disclosed, including a frame 3, a telescopic joint drive 13, and a movable functional component 8. Inside the frame 3 are a first connecting shaft 2, a second connecting shaft 4, and a third connecting shaft 6 arranged in parallel, as well as a first link 7, a second link 10, and a third link 12. The telescopic joint drive 13 is arranged within the frame and has a fixed end 1 and a movable end 5 capable of telescopic movement relative to the fixed end 1. The fixed end 1 is sleeved on the first connecting shaft 2 and can swing around the axis of the first connecting shaft 2. The movable end 5 is hinged to one end of the first link 7 and one end of the second link 10. The other end of the first link 7 is hinged to one end of the third link 12. The other end of the second link 10 is connected to the second connecting shaft 4 and can swing around the axis of the second connecting shaft 4. The other end of the third link 12 is connected to the third connecting shaft 6 and can swing around the axis of the third connecting shaft 6. Inside the frame, the second connecting shaft 4 is located between the first connecting shaft 2 and the third connecting shaft 6. The movable functional component 8 is fixedly connected to the third link 12 and can swing around the axis of the third link 6 along with the third link 12 when the movable end 5 of the telescopic joint drive component performs telescopic movement.

[0027] The second connecting shaft 4 is located between the first connecting shaft 2 and the third connecting shaft 6. Through the rigid connection between the connecting shaft and the frame, it provides a stable hinge reference for the first link 7, the second link 10, and the third link 12. The telescopic joint drive component 13 is the power input source for the entire multi-link mechanism. Through the relative telescopic movement of its fixed end 1 and movable end 5, it transmits linear power to the first link 7 and the second link 10, thereby driving the entire multi-link system to move in unison. Through the swinging characteristics of the fixed end 1 around the first connecting shaft 2, combined with the hinged design of the movable end 5 with the first link 7 and the second link 10, the telescopic joint drive component 13 can convert its own linear telescopic movement into a composite motion of swinging and pushing of the first link 7 and the swinging motion of the second link 10 around the second connecting shaft 4, thereby initiating the coordinated motion of the multi-link system, and finally converting it into the rotational motion of the movable functional component 8. The movable functional component 8, as the motion output component of the multi-link mechanism, is fixedly connected to the third link 12. It converts the rotational motion generated by the multi-link linkage into the actual movement of the robot's limbs, directly determining the motion effect of the joint mechanism. It is the core execution component for realizing the robot's limb posture adjustment. While outputting rotational motion, the movable functional component 8 also needs to bear the weight of the robot's limbs or external working loads and transmit the load force to the third link 12. Then, the load force is distributed to the first link 7, the second link 10, and each connecting shaft through the third link 12.

[0028] This legged robot's single-degree-of-freedom multi-link mechanism distributes the driving force of the actuators through multiple hinge points, distributing it to the second and third shafts via the first and second links. The load is shared by multiple links and shafts, rather than a single joint. This distributes force across multiple links, resulting in a stronger load-bearing capacity and greater load capacity compared to traditional mechanisms where a single joint supports the forces at rotating joints. It also addresses the problem in existing serial structures where the load is concentrated on a single active joint, leading to deformation, jamming, and insufficient load-bearing capacity.

[0029] Among them, the single-degree-of-freedom multi-link mechanism of the legged robot, as a single-degree-of-freedom rotation mechanism, can be used in various parts of the bionic legged robot such as the knee, elbow, and hip in practical applications. In this embodiment, the application of the single-degree-of-freedom multi-link mechanism of the legged robot to the knee joint is used as an example for detailed description.

[0030] In this embodiment, the single-degree-of-freedom multi-link mechanism of the legged robot, which serves as the integral structure of the knee joint, can be composed of a first link 2, a second link 4, a third link 6, a first link 7, a movable functional component 8, a first hinge axis 9, a second link 10, a second hinge axis 11, a third link 12, and a telescopic joint drive component 13. The frame 3 can be composed of two parallel mounting plates. The mounting plate, as the core load-bearing component, is rigidly connected to the robot's thigh component, and the first link 2, the second link 4, and the third link 6 are arranged in parallel on its surface. The second link 4 is located between the first link 2 and the third link 6. The rigid connection between the link and the frame ensures accurate swing trajectories of each link around the link, avoiding motion jamming or accuracy loss due to link position deviations.

[0031] The extension and retraction of the telescopic joint drive component 13 can synchronously drive the first link 7 and the second link 10 to move, providing initial power for subsequent multi-link linkage, triggering the swing of the third link 12, and thus driving the movable functional component 8 to rotate.

[0032] In knee joint applications, the movable functional component 8 can serve as a lower leg component. Its rotational movement around the third linkage 6 can directly realize the bending and extension movements of the robot's leg, meeting the gait requirements. When the bionic legged robot walks, the ground reaction force borne by the movable functional component 8 can be transmitted to the first linkage 7 and the second linkage 10 through the third linkage 12, and finally distributed to the frame by each linkage, and then transmitted to the robot body, realizing the distributed bearing of load force and improving the load capacity of the joint.

[0033] In this embodiment, the other end of the second connecting rod 10 is sleeved on the second connecting shaft 4 and rotates around the second connecting shaft 4; the other end of the third connecting rod 12 is sleeved on the third connecting shaft 6 and can rotate around the third connecting shaft 6; the movable end 5 of the telescopic joint drive member can rotate around the same axis as one end of the first connecting rod 7 and one end of the second connecting rod 10.

[0034] The interlocking connection of the links and shafts provides a defined rotational reference for the second and third links, preventing lateral movement or offset of the links during motion. It also ensures the rotational freedom of the links around the shafts, making it a key support for achieving multi-link coordinated operation. When a legged robot bears a load, this structure prevents uneven stress caused by link swaying, ensuring that the load force is stably transmitted to the frame through the links and shafts, improving the overall load-bearing stability of the joints and reducing component fatigue damage.

[0035] By integrating the hinge point of the movable end 5 of the drive component with the hinge point of the first link 7 and the second link 10 into the same axis, it is ensured that the driving force can be transmitted to the first link 7 and the second link 10 simultaneously and evenly, avoiding power transmission lag or uneven force due to the different axes of the hinge points, and ensuring the consistency of multi-link coordinated motion.

[0036] In this embodiment, the movable functional component 8 is fixedly connected to the bushing end of the other end of the third link 12, and the movable functional component 8 is bent at a fixed angle relative to the third link 12. This fixed connection ensures lossless motion transmission, and the fixed bending angle matches the movement direction of the movable functional component with the swing direction of the third link.

[0037] The movable functional component 8 is fixedly connected to the bushing end of the other end of the third link 12, with no relative movement gap between them. The rotational motion of the third link 12 around the third shaft 6 can be completely transmitted to the movable functional component 8. The fixed connection between the movable functional component and the third link ensures that every slight oscillation of the third link can synchronously drive the movable functional component to rotate, avoiding motion lag or angle loss caused by loose connection. For example, in the knee joint, when the third link rotates a certain angle, the movable functional component can precisely and synchronously rotate the same angle, meeting the accuracy requirements of robot gait control.

[0038] In this embodiment, one end of the second link 10 and one end of the third link 12 both extend toward the same side of the frame and are respectively hinged to both ends of the first link 7.

[0039] Specifically, by limiting the extension direction and hinge relationship of the second link 10 and the third link 12, the second link 10, the third link 12 and the first link 7 are made to form a hinge relationship that converges in the same direction within the frame. The motion trajectories of the three are concentrated in the same area of ​​the frame, avoiding motion interference caused by the intersecting extension directions of the links. This ensures that the motion trajectories of the two do not interfere with each other during power transmission, while shortening the power transmission path and improving the joint motion response speed, thus providing support for the compact design of the mechanism.

[0040] In this embodiment, in the knee joint mechanism, both the second link 10 and the third link 12 extend towards the movable functional component 8. After being hinged to the first link 7, the three links will not collide with other components in the frame, such as the mounting plate, when they move together. The unidirectional link layout allows the power of the telescopic joint drive component 13 to be transmitted to the first and second links via the movable end, and then quickly transmitted to the third link without having to go around in other directions. This shortens the power transmission path, reduces power loss, and improves the joint movement response speed, which can meet the gait requirements of rapid flexion and extension of the knee joint when the bionic legged robot walks.

[0041] In this embodiment, as Figures 2-3 As shown, when the single-degree-of-freedom multi-link mechanism of the legged robot is used in the leg component, the movable functional component 8 is used to drive the lower leg component to rotate relative to the upper leg component. When the single-degree-of-freedom multi-link mechanism of the legged robot is used in the arm component, the movable functional component 8 is used to drive the forearm component to rotate relative to the upper arm component.

[0042] Specifically, when the single-degree-of-freedom multi-link mechanism is used for the leg component, the movable functional component 8, as the lower leg component, is fixedly connected to the third link 12 and rotates around the third axis 6 along with the third link 12, realizing the flexion and extension movement of the thigh component, which is fixed relative to the frame and mounting plate. When the single-degree-of-freedom multi-link mechanism is used for the arm component, the movable functional component 8, as the forearm component, rotates around the third axis 6 along with the third link 12, realizing the rotation movement of the upper arm component, which is fixed relative to the frame.

[0043] In addition, the telescopic joint drive component 13 can be a linear electric drive joint module or a hydraulic cylinder, or other linear drive components. Appropriate drive components can be selected according to different load and accuracy requirements.

[0044] In this embodiment, the telescopic length of the telescopic joint drive 13 is configured based on the target rotation angle β obtained through pre-calculation and the length of the telescopic joint drive. l 1 The target rotation angle β is determined by the corresponding relationship and the target rotation angle β to be achieved; the target rotation angle is the angle formed by the swing of the movable functional component around the axis of the third connecting shaft 6 and the set reference datum plane.

[0045] Specifically, by pre-calculating the correspondence, errors in real-time calculation are avoided. At the same time, the drive length is determined directly based on the target rotation angle of the movable functional component 8, reducing the accumulated error in the multi-link transmission process from the source and ensuring that the movable functional component 8 can accurately reach the set angle position. The motion control of the single-degree-of-freedom multi-link mechanism is transformed into a matching logic based on the target angle to calculate the drive length, which reduces the real-time calculation pressure on the kinematic model of the mechanism and also facilitates the subsequent debugging and optimization of the mechanism's motion parameters.

[0046] In this embodiment, the target rotation angle β and the length of the telescopic joint drive component are obtained through pre-calculation. l The correspondence is as follows: ;in l BD The rod length should be a positive value. .

[0047] This involves transforming a single-degree-of-freedom multi-link mechanism into a corresponding geometrically simplified analysis model, such as... Figure 4 As shown, l 1 represents the length of the geometrically simplified feature AB of the telescopic joint drive component. l 6 represents the length of AE between the first simplified point A and the second simplified point E of the coupling axis. l 2 represents the BE length between the first simplified hinge point B and the second simplified coupling point E. l 3 represents the length BC between the second simplified hinge point C and the first simplified hinge point B. l4 represents the length of CD between the simplified point D of the third coupling and the simplified point C of the second hinge. l 5 represents the length of DE between the simplified point D of the third axis and the simplified point E of the second axis, and the target rotation angle β is the angle between CD and the horizontal straight line.

[0048] In this context, the variable link AB represents the telescopic joint drive component 13 in the single-degree-of-freedom multi-link mechanism of the legged robot, which is the core power transmission component for realizing the active movement of the joint. The length... l 1 represents the real-time working length of the telescopic joint drive component 13, which is the straight-line distance between the hinge points at both ends of the drive component during the telescopic process. Its length changes dynamically with the telescopic movement of the drive component.

[0049] The first simplified link point A represents the center of the hinge connection between the fixed end of the telescopic joint drive component 13 and the first link 7. This point is fixed by the frame, providing a fixed reference for the geometric analysis of the entire single-degree-of-freedom multi-link mechanism, and its position does not shift with joint movement. The second simplified link point E represents the center of the hinge connection used to connect the second link 10 and the second link 7; the third simplified link point D represents the center of the hinge connection between the third link 12, the movable functional component 8, and the third link 6; the first simplified hinge point B represents the center of the hinge connection between the movable end 5 of the telescopic joint drive component, the first link 7, the second link 10, and the second hinge shaft 11; the second simplified hinge point C represents the center of the hinge connection between the first link 7, the third link 12, and the first hinge shaft 9.

[0050] In this embodiment, the relationship between the target rotation angle and the length of the telescopic joint drive component can be pre-calculated through the following steps: Step S1: Obtain the component parameters of the single-degree-of-freedom multi-link mechanism of the legged robot; the component parameters include the corresponding lengths of the first link, the second link, and the third link, the distance between the axis of the first link and the axis of the second link, the distance between the axis of the second link and the axis of the third link, and the fixed angle parameters of each link position; define the physical characteristics of the target rotation angle to be analyzed, which is subject to the length adjustment of the telescopic joint drive component. A precise correlation between driving parameters and motion features is established. Through a three-step process of parameter acquisition, model construction, and relationship derivation, the physical characteristics of a single-degree-of-freedom multi-link mechanism are transformed into calculable mathematical relationships, providing a scientific basis for precise joint control and parameter optimization. By acquiring the lengths of the first, second, and third links, the distance between the links, and the fixed angle parameters of each link position, the physical boundary conditions of the mechanism are clarified. At the same time, the physical characteristics such as the rotation center and angle range of the target rotation angle are defined, providing basic data for subsequent model construction.

[0051] Step S2: Construct a geometric simplification analysis model corresponding to the single-degree-of-freedom multi-link mechanism of the legged robot. The geometric simplification analysis model is a feature geometric figure that simplifies each shaft and each hinge node to a point and each link to a straight line connecting two points. Through the topological relationship between the geometric figures, construct the correlation framework between the length and angle parameters of each component. Specifically, couplings and hinges are simplified to points, and links are simplified to lines, forming characteristic geometric figures. A length and angle-related framework is constructed through topological relationships such as the node connection sequence and link length constraints. This simplification removes redundant physical features of the mechanism, such as link shapes and frame contours, transforming complex multi-link motion analysis into a problem solvable by mathematical formulas, thus reducing the difficulty of analysis.

[0052] Step S3: Apply the cosine theorem to the characteristic geometry to derive the correspondence between the length of each link and the target rotation angle, and the correspondence between the length of each link and the length of the telescopic joint drive component 13, forming a two-level parameter mapping chain. Combine these two-level parameter mapping relationships to obtain the direct correspondence between the drive component length and the target rotation angle. By deriving the two-level mapping relationships between link length and target rotation angle, and link length and drive component length using the cosine theorem, and combining them, the direct relationship between the drive component length and the target rotation angle is obtained.

[0053] In this embodiment, as Figure 5 and 6 As shown, the geometrically simplified analysis model is established with the axis D of the third connecting shaft of the mechanism as the origin of the reference coordinate system. The fixed angle parameters of each link position include the initial angle ∠EDG formed by the line connecting the second and third connecting shafts and the reference coordinate system.

[0054] Specifically, by establishing a coordinate system with the axis D of the third link as the origin, all geometric parameters are based on the same reference, avoiding calculation errors caused by coordinate system confusion. At the same time, the definition of the fixed angle parameters of each link position is clarified, providing a unified reference for subsequent formula derivation.

[0055] In this embodiment, for each feature triangle in the geometrically simplified analysis model, a relationship is established between the square of the side length and the cosine of the two sides and the included angle. The key link length includes the length of the transition link connecting the drive component and the execution component. In the two-level parameter mapping chain, the first level mapping is a function relationship between the length of each link and the target rotation angle, and the second level mapping is a function relationship between the length of each link and the length of the drive component.

[0056] By applying the cosine theorem to each characteristic triangle, the multivariate relationship is decomposed into the side length-angle relationship within a single triangle. Then, through a two-level mapping chain, a direct connection between the driving component and the target rotation angle is finally established.

[0057] For each characteristic triangle in the geometric model, such as △BED, △BDC, and △BEA, establish the relationship "Side length squared = Two sides squared - 2 × Two sides × Cosine of included angle" to associate the side lengths of the triangle with the angle parameters.

[0058] A two-level parameter mapping function is constructed. The first level mapping establishes a functional relationship between the lengths of the third link 12, the second link 10, etc., and the target rotation angle, clarifying the variation of the rotation angle with the link length. The second level mapping establishes a functional relationship between the link length and the drive component length, clarifying the matching relationship between the required extension / retraction of the drive component and the link length. Combining the two levels of mapping eliminates intermediate variables, directly obtaining the correspondence between the drive component length and the target rotation angle, making it possible to directly call control parameters.

[0059] In this embodiment, the target rotation angle β and the length of the telescopic joint drive component are... l The steps for calculating and obtaining the correspondence are as follows: A simplified geometric analysis model of the single-degree-of-freedom multi-link mechanism of the legged robot is constructed, and a framework relating the lengths and angle parameters of each component is established. The length of the simplified geometric feature link AB of the telescopic joint drive component 13 is... l 1. The length of AE between the first simplified point A and the second simplified point E of the coupling axis is: l 6. The length BE between the first simplified hinge point B and the second simplified coupling point E is: l 2. The length of BC between the second simplified hinge point C and the first simplified hinge point B is... l 3. The length of CD between the simplified point D of the third coupling and the simplified point C of the second hinge is... l 4. The length of DE between the simplified point D of the third axis and the simplified point E of the second axis is... l 5. The angle between CD and the horizontal line is β; In this context, the variable link AB represents the telescopic joint drive component 13 in the single-degree-of-freedom multi-link mechanism of the legged robot, which is the core power transmission component for realizing the active movement of the joint. The length... l 1 represents the real-time working length of the telescopic joint drive component 13, which is the straight-line distance between the hinge points at both ends of the drive component during the telescopic process. Its length changes dynamically with the telescopic movement of the drive component.

[0060] The first simplified link point A represents the center of the hinge connection between the fixed end of the telescopic joint drive component 13 and the first link 7. This point is fixed by the frame, providing a fixed reference for the geometric analysis of the entire single-degree-of-freedom multi-link mechanism, and its position does not shift with joint movement. The second simplified link point E represents the center of the hinge connection used to connect the second link 10 and the second link 7; the third simplified link point D represents the center of the hinge connection between the third link 12, the movable functional component 8, and the third link 6; the first simplified hinge point B represents the center of the hinge connection between the movable end 5 of the telescopic joint drive component, the first link 7, the second link 10, and the second hinge shaft 11; the second simplified hinge point C represents the center of the hinge connection between the first link 7, the third link 12, and the first hinge shaft 9.

[0061] Construct triangles BED and BDC: ; Applying the Law of Cosines: ; ; Calculation yielded: ; ; Substitute ∠EDB and ∠BDC into the formula The calculation yields: ; In triangle BEA, applying the Law of Cosines: ; Calculation obtained ; ; Then it can be deduced that: ; In triangle BED, applying the law of cosines: , Substitute The calculation yielded: ; That's how you get it. l BD With fixed rod length l 1. l 2. l 5. l The relationship between 6 and ∠AED. In institutions, l 2. l 3 、l 4、l 5. l 6. ∠AED and ∠EDG are fixed values ​​and can be determined according to the actual application of the mechanism.

[0062] Thus, in the formula In the middle, ∠GDC only interacts with l 1 , l 2. l 3 、l 4 、l 5. l 6. Related to ∠AED and ∠EDG, among which l 1 The length of the link is variable. Thus, the length of the link in this mechanism is obtained. l 1 The relationship between the parameters and ∠GDC is then used to obtain the length of the telescopic joint drive component. l 1 The parameter relationship with the rotation angle β of the moving functional component: ; in l BD The rod length should be a positive value. .

[0063] Finally, the parametric relationship between the length l1 of the telescopic joint drive component and the rotation angle β of the movable functional component was calculated.

[0064] The above embodiments analyze the single-degree-of-freedom multi-link mechanism of a legged robot, completing the configuration solution of the single-degree-of-freedom multi-link mechanism and obtaining the relationship between the length of the telescopic joint drive component (i.e., the range change) and the target rotation angle. This allows for easy adaptation of each single-degree-of-freedom multi-link mechanism to various application scenarios during actual design or motion control, simply by readjusting the known quantities of the single-degree-of-freedom multi-link mechanism.

[0065] In one specific embodiment, taking the knee of a bionic legged robot as an example, the length of the rod... l 2 = 25.5mm, rod length l 3 = 22mm, rod length l 4 = 15mm, rod length l 5 = 22.5mm, rod length l 6 = 159.5mm, ∠EDG = 68°, ∠AED = 160°, and the linear joint travel is 154.5mm-188mm. The known rotation angle range of the movable functional component, the lower leg, is approximately -11° to 141°, as shown in the attached diagram. Figure 7As shown in the figure, the curve represents the relationship between the rotation angle β of the moving functional component and the stroke of the linear joint. It can be seen from the figure that the required stroke to complete the corresponding rotation angle is 158.5mm-180.5mm, and the actual stroke range of the linear joint is 154.5mm-188mm, which is within the stroke range of the joint.

[0066] When controlling the knee, the rotation angle of the lower leg, a movable functional component, is known. Therefore, using the solution method of this mechanism, the required rotation angle can be converted into the stroke of a linear joint, ensuring the knee can complete the corresponding flexion. Furthermore, in the field of biomimetic legged robots, this mechanism can be used for other parts of the robot with similar single rotational degrees of freedom, such as the knee, elbow, and hip. Through the use of linkage mechanisms, the linear motion of the drive pair is converted into rotational motion.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

[0068] In summary, the above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be covered by the present invention.

Claims

1. A single-degree-of-freedom multi-link mechanism for legged robots, characterized in that, include: The frame has a first, second, and third connecting shaft arranged in parallel inside; as well as a first, second, and third connecting rod; A telescopic joint drive component, arranged within the frame, has a fixed end and a movable end capable of telescopic movement relative to the fixed end. The fixed end is sleeved on the first connecting shaft and can swing around the axis of the first connecting shaft. The movable end is hinged to one end of the first connecting rod and one end of the second connecting rod via a second hinge axis. The other end of the first connecting rod is hinged to one end of the third connecting rod via a first hinge axis. The other end of the second connecting rod is connected to the second connecting shaft and can swing around the axis of the second connecting shaft. The other end of the third connecting rod is connected to the third connecting shaft and can swing around the axis of the third connecting shaft. Within the frame, the second connecting shaft is located between the first connecting shaft and the third connecting shaft. The movable functional component is fixedly connected to the third link and can swing around the third link axis as the movable end of the telescopic joint drive component performs telescopic movements.

2. The single-degree-of-freedom multi-link mechanism for legged robots according to claim 1, characterized in that: The other end of the second link is sleeved on the second connecting shaft and rotates around the second connecting shaft; the other end of the third link is sleeved on the third connecting shaft and can rotate around the third connecting shaft; the movable end of the telescopic joint drive component can rotate around the same axis as one end of the first link and one end of the second link. The movable functional component is fixedly connected to the bushing end of the other end of the third link, and the movable functional component is bent at a fixed angle relative to the third link body.

3. The single-degree-of-freedom multi-link mechanism for legged robots according to claim 2, characterized in that: One end of the second link and one end of the third link both extend toward the same side of the frame and are respectively hinged to both ends of the first link.

4. The single-degree-of-freedom multi-link mechanism for legged robots according to claim 3, characterized in that: The single-degree-of-freedom multi-link mechanism is used in the leg component, and the movable functional component is used to drive the movable functional component to rotate relative to the thigh component; or The single-degree-of-freedom multi-link mechanism is used in the arm component, and the movable functional component is used to drive the forearm component to rotate relative to the upper arm component.

5. The single-degree-of-freedom multi-link mechanism for legged robots according to claim 4, characterized in that: The telescopic joint drive component is a linear electric drive joint module or a hydraulic cylinder.

6. The single-degree-of-freedom multi-link mechanism for legged robots according to any one of claims 1-5, characterized in that: The telescopic length of the telescopic joint drive is configured to be determined based on the correspondence between the target rotation angle and the length of the telescopic joint drive obtained through pre-calculation, and the target rotation angle that needs to be achieved; the target rotation angle is the angle formed by the swing of the movable functional component around the third shaft axis and the set reference plane.

7. The single-degree-of-freedom multi-link mechanism for legged robots according to claim 6, characterized in that, The target rotation angle β and the length of the telescopic joint drive component are obtained through pre-calculation. l The correspondence is as follows: ;in l BD The rod length should be a positive value. ; This involves transforming a single-degree-of-freedom multi-link mechanism into a corresponding geometrically simplified analysis model. l 1 represents the length of the geometrically simplified feature AB of the telescopic joint drive component. l 6 represents the length of AE between the first simplified point A and the second simplified point E of the coupling axis. l 2 represents the BE length between the first simplified hinge point B and the second simplified coupling point E. l 3 represents the length BC between the second simplified hinge point C and the first simplified hinge point B. l 4 represents the length of CD between the simplified point D of the third coupling and the simplified point C of the second hinge. l 5 represents the length of DE between the simplified point D of the third axis and the simplified point E of the second axis, and the target rotation angle β is the angle between CD and the horizontal straight line.

8. The single-degree-of-freedom multi-link mechanism for a legged robot according to claim 7, characterized in that, The following steps are used to pre-calculate and obtain the relationship between the target rotation angle and the length of the telescopic joint drive component: Obtain the parameters of each component of the single-degree-of-freedom multi-link mechanism; the component parameters include the corresponding lengths of the first link, the second link, and the third link, the distance between the axis of the first link and the axis of the second link, the distance between the axis of the second link and the axis of the third link, and the fixed angle parameters of each link position; define the physical characteristics of the target rotation angle to be analyzed, which is subject to the length adjustment of the telescopic joint drive component; A geometric simplification analysis model is constructed for the single-degree-of-freedom multi-link mechanism. The geometric simplification analysis model is a feature geometric figure that simplifies each connecting shaft and each hinge node to a point and each link to a straight line connecting two points. Through the topological relationship between the geometric figures, a framework for the association between the length and angle parameters of each component is constructed. Applying the law of cosines to the feature geometry, the correspondence between the length of each link and the target rotation angle, and the correspondence between the length of each link and the length of the telescopic joint drive component are derived sequentially, forming a two-level parameter mapping chain; combining the above two-level parameter mapping relationships, the direct correspondence between the length of the drive component and the target rotation angle is obtained.

9. The single-degree-of-freedom multi-link mechanism for legged robots according to claim 8, characterized in that: The geometrically simplified analysis model is established with the third shaft of the mechanism as the origin of the reference coordinate system. The fixed angle parameters of each link position include the initial angle formed by the line connecting the second and third shafts and the reference coordinate system. For each characteristic triangle in the geometrically simplified analysis model, a relationship is established between the square of the side length and the cosine of the two sides and the included angle. The key link length includes the length of the transition link connecting the drive component and the execution component. In the two-level parameter mapping chain, the first level mapping is a function relationship between the length of each link and the target rotation angle, and the second level mapping is a function relationship between the length of each link and the length of the drive component.

10. The single-degree-of-freedom multi-link mechanism for a legged robot according to claim 6, characterized in that, The steps for calculating the relationship between the target rotation angle and the length of the telescopic joint drive component are as follows: A simplified geometric analysis model of the single-degree-of-freedom multi-link mechanism is constructed, and a framework relating the lengths and angles of each component is established. The simplified geometric feature of the telescopic joint drive component is transformed into a length AB of... l 1. The length of AE between the first simplified point A and the second simplified point E of the coupling axis is: l 6. The length of BE between the simplified first hinge point B and point E is... l 2. The length of BC between the simplified second hinge point C and point B is: l 3. The simplified length of CD between point D and point C in the third axis is... l 4. The length of DE between points D and E is l5, where the angle between CD and the horizontal line is β; Construct triangles BED and BDC: Applying the Law of Cosines: , ; Calculation yielded: ； ； Substitute ∠EDB and ∠BDC into the formula The calculation yielded: ； In triangle BEA, applying the Law of Cosines: ; Calculation obtained ； ； Then it can be deduced that: ; In triangle BED, applying the law of cosines: , bring in The calculation yielded: ； Received l BD With fixed rod length l 1. l 2. l 5. l The relationship between 6 and ∠AED was used to obtain the rod length in the mechanism after conversion. l 1 The parameter relationship with ∠GDC; final Obtain the length of the telescopic joint drive component l 1 The parameter relationship with the rotation angle β of the moving functional component: ;in l BD The rod length should be a positive value. .

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