Knee joint structure, knee joint movement method and mechanical leg

Abstract

The application belongs to the field of mechanical legs, and particularly relates to a knee joint structure, a knee joint movement method and a mechanical leg, wherein the knee joint structure comprises a four-bar linkage mechanism and a rotating wheel mechanism; the four-bar linkage mechanism comprises sequentially hinged connecting rod I, connecting rod II, connecting rod III and connecting rod IV in head-tail mode, wherein the connecting rod I is used for connecting the thigh of the mechanical leg, and the connecting rod III is used for connecting the lower leg of the mechanical leg; the rotating wheel mechanism comprises connecting rod V and connecting rod VI which are hingedly connected to each other, a transmission wheel I is rotationally arranged on the hinged axis of the connecting rod V and the connecting rod VI, a driving / driven wheel which rotationally cooperates with the transmission wheel I is rotationally arranged on the connecting rod V, the driving / driven wheel is rotationally arranged on the connecting rod I, a driven / driving wheel which rotationally cooperates with the transmission wheel I is rotationally arranged on the connecting rod VI, and the driven / driving wheel is rotationally arranged on the connecting rod III. The application has excellent optimization effect in passive movement stability, structural bearing capacity and module redundancy design.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of mechanical legs, and particularly relates to a knee joint structure, a knee joint movement method and a mechanical leg. BACKGROUND

[0002] One of the core development goals in the technical field of knee prostheses or powered exoskeletons is to simulate the natural, stable and efficient biomechanical characteristics of the human knee joint. A healthy knee joint exhibits a complex instantaneous center of rotation (instantaneous center) trajectory during flexion and extension, which is crucial for achieving smooth and stable gait. At the same time, such devices not only need to be able to work under active power driving, but also must have inherent stability, impact resistance and load reliability when passive movement (such as being pushed or swung by external force) under power interruption (such as power depletion, system failure), which is crucial for user safety and device practicality.

[0003] Currently, there are mainly the following ways to design the mechanism that simulates knee joint movement:

[0004] 1. Pure hinge or simple single-axis hinge: the structure is the simplest, but the instantaneous center trajectory is very different from that of a healthy knee joint, resulting in unnatural gait, low energy efficiency, and lack of constraints on complex movements in passive state, which is prone to shaking or uncontrolled displacement.

[0005] 2. Four-bar linkage mechanism: compared with single-axis hinge, it can simulate a more human-like instantaneous center trajectory, improve the naturalness of movement, and provide better internal structural stability and load capacity. However, traditional four-bar linkage mechanisms still have limitations in fitting accuracy and flexibility of instantaneous center trajectory. Although its passive stability is better than single-axis, the motion coordination inside the joint cannot be compared with complex structures with motion constraints. Pure passive four-bar linkage mechanism still has room for improvement in movement smoothness and anti-shaking.

[0006] 3. Bionic knee joint structure based on five-bar linkage and three gears: (such as Chinese invention patent CN103976807B - "Prosthetic knee joint of gear five-bar mechanism"). This type of design tries to precisely control the instantaneous center trajectory and the relative motion angle between the links through additional link and gear constraint mechanisms. However, this type of structure has exposed a series of key problems in practice, especially in the challenges of device safety and robustness. For example, the high integration of this type of mechanism is both its advantage and disadvantage. When the active power drive fails or is disconnected, the system exposes its essential vulnerability. In some specific angle positions, the complex linkage system is prone to get stuck in the mechanical dead point. In the active driving state, it can be overcome by inertia or driving force; but in the passive movement (such as slowly swinging the lower leg by external force) with small inertia, the system is more likely to get stuck near the dead point, resulting in discontinuous movement or even complete jamming.

[0007] In summary, existing technologies, especially the five-link three-gear mechanism, have obvious deficiencies in stability in the passive state (resisting jamming, suppressing shaking, and maintaining a certain trajectory), impact resistance, ultimate load-bearing capacity, and modular system robustness and redundant design. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a knee joint structure, a knee joint movement method and a mechanical leg that embody excellent optimization effects in terms of passive motion stability, structural bearing capacity and modular redundancy design.

[0009] The present invention provides a knee joint structure, comprising a four-bar linkage mechanism and a rotating wheel mechanism;

[0010] The four-bar linkage includes a link I, a link II, a link III, and a link IV which are hinged end to end in sequence, wherein the link I is used to connect the thigh of the mechanical leg, and the link III is used to connect the shank of the mechanical leg;

[0011] The rotating wheel mechanism includes a connecting rod V and a connecting rod VI that are hinged to each other, and a transmission wheel I is rotatably provided on the hinge axis of the connecting rod V and the connecting rod VI, and a master / driven wheel that is rotatably coordinated with the transmission wheel I is rotatably provided on the connecting rod V, and the master / driven wheel is rotatably provided on the connecting rod I, and a slave / driving wheel that is rotatably coordinated with the transmission wheel I is rotatably provided on the connecting rod VI, and the slave / driving wheel is rotatably provided on the connecting rod III.

[0012] Furthermore, a connecting rod is provided on the connecting rod III, and the connecting rod includes a connecting rod I, a connecting rod II and a connecting rod III connected in sequence;

[0013] The connecting rod I and the connecting rod III are parallel to each other, and one end of the connecting rod I is fixed to the connecting rod III;

[0014] The end of the connecting rod III is rotatably arranged to set the driven / driving wheel.

[0015] Furthermore, the projection of the axis of the slave / driving wheel onto the plane of the four-bar linkage is located on the connecting rod III.

[0016] Furthermore, the connecting rod I is coplanar with the plane of the four-bar linkage, and the slave / driving wheel is located between the connecting rod I and the connecting rod II.

[0017] Furthermore, the transmission wheel I, the master / driven wheel and the slave / driving wheel are located between the four-bar linkage and the connecting rods V and VI.

[0018] Furthermore, the rotation axis of the master / driven wheel is coaxial with the articulation axis of the connecting rod I and the connecting rod II.

[0019] Furthermore, the length of the connecting rod I is 27 mm, the length of the connecting rod II is 80 mm, the length of the connecting rod III is 45 mm, and the length of the connecting rod IV is 45 mm.

[0020] Furthermore, the transmission ratio of the master / driven wheel and the slave / driving wheel is 1.

[0021] The present invention also provides a knee joint motion method, using the above-mentioned knee joint structure, including active knee joint motion and passive knee joint motion;

[0022] The active knee joint movement comprises the following steps:

[0023] The power output drives the master / slave wheel or slave / driving wheel to rotate, and the master / slave wheel or slave / driving wheel drives the slave / driving wheel or master / slave wheel to rotate through the transmission wheel I;

[0024] At the same time, the four-bar linkage mechanism and the rotating wheel mechanism move in coordination, so that the four-bar linkage mechanism moves along a specific trajectory;

[0025] The driven knee joint movement comprises the following steps:

[0026] The connecting rod I or the connecting rod III moves passively, and cooperates with the rotating wheel mechanism during the passive movement to make the four-bar linkage move along a specific trajectory.

[0027] The present invention also provides a mechanical leg, which includes the above-mentioned knee joint structure.

[0028] The beneficial effect of the present invention is that the four-bar linkage in the knee joint structure is equivalent to a structurally stable main chain, while the rotating wheel mechanism is equivalent to a speed-coordinating secondary chain. This not only achieves or even surpasses the motion coordination of a traditional five-bar, three-gear knee joint structure, but also demonstrates excellent optimization effects in passive motion stability, structural load-bearing capacity, and modular redundancy design. In contrast, the traditional five-bar, three-gear structure is simple and fragile when power is interrupted, with the force primarily borne by the three gears. The concentrated load borne by the three gears makes them more susceptible to failure during prolonged use or external impact, reducing the safety and reliability of the system.

[0029] The knee joint structure provided by the present invention maintains a synchronously coupled motion relationship between the four-bar linkage and the rotating wheel mechanism after the active force is disconnected, and the system can autonomously maintain a passive motion trajectory; the stability, anti-vibration ability and load balance in the passive state are better, and it is suitable for scenarios with high robustness requirements.

[0030] Therefore, the four-bar linkage of the present invention itself constitutes a closed load-bearing path with natural structural stability. The two-link + three-gear system in the rotating wheel mechanism plays the role of angular velocity constraint, torque transmission and trajectory fine-tuning in the structure. After the two are combined, the load transfer path is shared by multiple channels, which significantly improves the impact resistance and ultimate bearing capacity of the overall structure. After the main force is disconnected, the coupling of the four-bar linkage and the rotating wheel mechanism can be relied upon to achieve stable passive gait simulation, which is significantly better than the mechanical instability problem of the five-bar linkage under power-off conditions.

[0031] In addition, in the traditional gear four-bar mechanism, two or three gears are directly rotated and set on two or three hinge axes of the four-bar mechanism. When applied to the knee joint, its essence is no different from the traditional five-bar three-gear structure. The present knee joint structure is optimized for the application scenario of the knee joint. The master / driven wheels and slave / driving wheels in the rotating wheel mechanism do not have to be installed on the hinge axis of the four-bar mechanism, and the axis of the transmission wheel I is independent of the four-bar mechanism, so that it can be coupled and constrained with the four-bar mechanism, thereby achieving excellent knee joint structure motion coordination, high impact resistance and ultimate load-bearing capacity.

[0032] By tailoring the dimensions of the four-bar linkage and the rotating wheel mechanism, a customized trajectory can be achieved, generating a complex, dynamically adjustable curve that closely matches the instantaneous trajectory of a healthy knee joint, surpassing the fitting capabilities of a pure four-bar mechanism. This ultimately results in a more natural and efficient gait, with enhanced adaptability to varying terrains, such as slopes and stairs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Attachment Figure 1 Schematic diagram of the first angle structure of the knee joint system of the present invention;

[0034] Attachment Figure 2 2 is a schematic diagram of the second angle structure of the knee joint system of the present invention;

[0035] Attachment Figure 3 This is a schematic diagram of the first angle structure of the knee joint structure of the present invention;

[0036] Attachment Figure 4 2 is a schematic diagram of the second angle structure of the knee joint structure of the present invention;

[0037] Attachment Figure 5 This is a front view of the initial angle of the knee joint structure of the present invention;

[0038] Attachment Figure 6 A front view of the knee joint structure at a middle angle according to the present invention;

[0039] Attachment Figure 7 This is a front view of the extreme flexion angle of the knee joint structure of the present invention;

[0040] Attachment Figure 8 A schematic diagram of the dimensions of a four-bar linkage mechanism in one embodiment of the present invention;

[0041] Attachment Figure 9 Schematic diagram of the motion of the four-bar linkage in the present invention;

[0042] Attachment Figure 10 is a motion curve diagram of the four-bar linkage mechanism in the present invention;

[0043] Attachment Figure 11 Schematic diagram of the coordination between the active-passive switching structure and the rotary drive mechanism in the present invention;

[0044] Attachment Figure 12 Schematic diagram of the active-passive switching structure of the present invention;

[0045] Attachment Figure 13 Schematic diagram of the structure when the driving wheel and the driven wheel are connected in the active-passive switching structure of the present invention;

[0046] Attachment Figure 14 This is a schematic diagram of the structure when the driving wheel and the driven wheel are separated in the active-passive switching structure of the present invention.

[0047] In the figure, 1-four-bar linkage; 11-connecting rod I; 12-connecting rod II; 13-connecting rod III; 14-connecting rod IV; 15-connecting rod I; 16-connecting rod II; 17-connecting rod III; 2-rotating wheel mechanism; 21-connecting rod V; 22-connecting rod VI; 23-transmission wheel I; 24-master / driven wheel; 25-slave / driving wheel; 3-master-passive switching structure; 31-driving wheel; 32-transmission wheel II; 33-driven wheel; 34-bracket; 35-rotating member; 36-clutch lever; 37-slide plate; 371-arc slide; 38-elastic member; 39-locking connecting rod; 310-slider; 311-rotating rod; 312-manual operating lever; 4-rotation driving mechanism; 41-motor; 42-gear set; 43-bevel gear set. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention 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. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0049] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0050] In addition, the terms "first," "second," and so on, used in this disclosure are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referenced. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this disclosure, "plurality" means at least two, such as two or three, unless otherwise specifically defined.

[0051] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; it can mean mechanical connection, electrical connection, physical connection, or wireless communication connection; it can mean direct connection or indirect connection through an intermediate medium; it can mean internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0053] As attached Figure 1 -Attached Figure 14 As shown, the present invention provides a knee joint structure, comprising a four-bar linkage mechanism 1 and a rotating wheel mechanism 2;

[0054] The four-bar linkage 1 includes a link I 11, a link II 12, a link III 13, and a link IV 14, which are hinged end to end in sequence. The link I 11 is used to connect the thigh of the mechanical leg, and the link III 13 is used to connect the shank of the mechanical leg. That is, the two opposite links in the four-bar linkage are used to connect the thigh and shank of the mechanical leg respectively.

[0055] The rotating wheel mechanism 2 includes a connecting rod V21 and a connecting rod VI22, which are hinged to each other. A transmission wheel I23 is rotatably mounted on the hinge axis of the connecting rods V21 and VI22. A master / slave wheel 24 is rotatably mounted on the connecting rod V21, which rotates in conjunction with the transmission wheel I23. The master / slave wheel 24 is rotatably mounted on the connecting rod I11. A slave / driving wheel 25 is rotatably mounted on the connecting rod VI22, which rotates in conjunction with the transmission wheel I23. The slave / driving wheel 25 is rotatably mounted on the connecting rod III13. In other words, the master / slave wheel 24, the transmission wheel I23, and the slave / driving wheel 25 are sequentially meshed, and their motion trajectory is simultaneously restricted by the connecting rods V21, VI22, and the four-bar linkage 1. The master / slave wheel 24 can function as the driving wheel, in which case the slave / driving wheel 25 becomes the driven wheel. Conversely, the master / slave wheel 24 can function as the driven wheel, in which case the slave / driving wheel 25 becomes the driving wheel. The driving wheel can be connected to the rotary drive mechanism 4, thereby actively driving the transmission wheel I 23 and the driven wheel to rotate, driving the four-bar linkage 1 along its specific motion trajectory. The driving wheel can also be separated from the rotary drive mechanism 4. In this case, the master / slave wheel 24, transmission wheel I 23, and slave / driving wheel 25 are all driven by the deformation of the four-bar linkage 1 and rotate passively. Both the master / slave wheel 24 and the slave / driving wheel 25 serve as both driving and driven wheels.

[0056] In this invention, the four-bar linkage 1 in the knee joint structure functions as a structurally stable main chain, while the rotating wheel mechanism 2 functions as a speed-coordinating secondary chain. This design not only achieves or even surpasses the motion coordination of a conventional five-bar, three-gear knee joint (Chinese Invention Patent CN103976807B - A Prosthetic Knee Joint with a Geared Five-Bar Mechanism), but also demonstrates excellent optimization in passive motion stability, structural load-bearing capacity, and modular redundancy. In contrast, the conventional five-bar, three-gear structure exhibits a single, fragile structure when power is interrupted. The load is primarily borne by the three gears, and the concentrated load borne by these three gears makes them more susceptible to failure during prolonged use or external impact, reducing the safety and reliability of the system.

[0057] Specifically, after the power system fails or is disconnected, the traditional five-link three-gear structure will have the following problems: dead point sticking phenomenon: the multi-link system is prone to get stuck in the mechanical dead point at some angles, and it is difficult to pass through due to lack of inertia. Therefore, the traditional five-link three-gear structure is more prone to dead point sticking phenomenon. Instability and shaking: the degree of freedom is redundant, and it is difficult to stably maintain the relative angle of the link after losing active control, resulting in loose or shaking structure. Path uncertainty: the movement trajectory depends on the driving force, and there is no passive trajectory guidance or closed-loop constraint. High risk of user imbalance: the user lacks control when relying on external force to swing, and there is a risk of falling due to the unbound structure. The knee joint structure provided by the present application can still maintain synchronous coupling motion between the four-link mechanism 1 and the rotating wheel mechanism 2 after the active force is disconnected, and the system can autonomously maintain the passive motion trajectory. The stability, anti-shaking ability and load balancing in passive state are better, and it is suitable for high robustness demand scenarios (such as walking without power, anti-falling, etc.).

[0058] Therefore, the four-link mechanism 1 itself constitutes a closed load bearing path, which has natural structural stability. The two-link + three-gear system in the rotating wheel mechanism 2 plays a role in angular velocity constraint, torque transmission and trajectory fine-tuning in the structure. After the combination of the two, the load transmission path is shared by multiple paths, which significantly improves the impact resistance and ultimate bearing capacity of the overall structure. After the active force is disconnected, stable passive gait simulation can be realized by relying on the coupling of the four-link mechanism 1 and the rotating wheel mechanism 2, which is significantly better than the mechanical instability problem of the five-link mechanism under the condition of power failure.

[0059] In addition, in the traditional gear four-link mechanism, two or three gears are directly arranged on two or three hinge axes of the four-link mechanism. When applied to the knee joint, its essence is no different from the traditional five-link three-gear structure. The knee joint structure is optimized for the application scenario of the knee joint. The master / slave wheel 24 and the slave / master wheel 25 in the rotating wheel mechanism 2 are not necessarily installed on the hinge axis of the four-link mechanism 1, and the axis of the transmission wheel I 23 is independent of the four-link mechanism 1, which can be coupled and constrained with the four-link mechanism 1 to achieve excellent motion coordination, high impact resistance and ultimate bearing capacity of the knee joint structure.

[0060] By designing the size of the four-link mechanism 1 and the rotating wheel mechanism 2, reference Figures 8-10, can achieve customized trajectories, generating complex, dynamically adjustable curves that closely match the instantaneous trajectory of a healthy knee joint, surpassing the fitting capabilities of a pure four-bar mechanism. This ultimately makes gait more natural and efficient, and more adaptable to different terrains such as slopes and stairs.

[0061] It should be noted that in this application, the master / slave wheel 24, the transmission wheel I 23 and the slave / driving wheel 25 are preferably gears, but since the coupling of the four-bar linkage 1 and the rotating wheel mechanism 2 achieves stable passive gait simulation, friction wheels can also be used.

[0062] In one embodiment, the connecting rod III 13 is provided with a connecting rod, and the connecting rod includes a connecting rod I 15, a connecting rod II 16 and a connecting rod III 17 connected in sequence;

[0063] The connecting rod I 15 and the connecting rod III 17 are parallel to each other, and one end of the connecting rod I 15 is fixed to the connecting rod III 13;

[0064] The end of the connecting rod III 17 is rotatably provided with the driven / driving wheel 25 .

[0065] In this embodiment, by providing a connecting rod, on the one hand, the calf of the mechanical leg can be connected via connecting rod I 15 or connecting rod III 17, thereby achieving a relatively distant connection position between the calf and the four links in the four-bar linkage 1, avoiding a compact area, ensuring the range of motion of the four-bar linkage 1, and facilitating connection with the slave / driving wheel 25. On the other hand, the provision of the connecting rod can extend the moment arm and improve torque transmission efficiency.

[0066] In a preferred embodiment, the end of the connecting rod III 17 is hinged to the end of the connecting rod VI 22, thereby realizing the interconnection of the four connecting rods in the four-bar linkage 1 and the two connecting rods of the rotating wheel mechanism 2, greatly improving the load transfer path of the overall structure, improving the load capacity, and at the same time improving the structural stability of the overall structure.

[0067] In one embodiment, the projection of the axis of the slave / driving wheel 25 onto the plane of the four-bar linkage 1 is located on the connecting rod III 13. This arrangement can make the motion trajectory of the slave / driving wheel 25 completely equivalent to that when it is directly rotated on the connecting rod III 13, without affecting the coupling between the four-bar linkage 1 and the rotating wheel mechanism 2.

[0068] In one of the embodiments, the connecting rod 115 is coplanar with the plane of the four-bar linkage 1, and the driven / motor wheel 25 is located between the connecting rod 115 and the connecting rod 116. In this way, the driven / motor wheel 25 can be stably and reliably fixed. The connecting rod 115 and the connecting rod 116, which are two rigid rods, can constitute a protective bracket for the driven / motor wheel 25. Preferably, the driven / motor wheel 25 can be connected to the connecting rod 115 and the connecting rod 116 away from one end of the connecting rod 113, or the driven / motor wheel 25 can be connected to the connecting rod 116 and the connecting rod 113, so that the driven / motor wheel 25 is a double-point fixed structure, greatly improving the rotation stability of the driven / motor wheel 25.

[0069] In one of the embodiments, the transmission wheel 123, the motor / driven wheel 24, and the driven / motor wheel 25 are located between the four-bar linkage 1 and the connecting rod 121 and the connecting rod 122.

[0070] In this embodiment, the three wheel bodies are located between the two groups of rods, making the overall structure compact, and the two groups of rods constitute the physical protection of the wheel bodies.

[0071] In one of the embodiments, the rotation axis of the motor / driven wheel 24 is coaxial with the hinge axes of the connecting rod 111 and the connecting rod 112.

[0072] In this way, not only can the rotation of the connecting rod be completely synchronized with the gear drive, improving the motion consistency and transmission efficiency, but also the structure can be greatly simplified, the torque transmission path can be shortened, the flexion and deflection torque can be better resisted, and the structural rigidity and stability can be enhanced. In particular in the passive mode, the structure can stably respond to external force driving, avoiding the phenomenon of swing out of control or load transmission imbalance.

[0073] In one of the embodiments, the length of the connecting rod 111 is 27 mm, the length of the connecting rod 112 is 80 mm, the length of the connecting rod 113 is 45 mm, and the length of the connecting rod 114 is 45 mm. In this embodiment, referring to Figure 3-10 , the four-bar linkage 1 coupled with the rotating wheel mechanism 2 can realize a specific motion trajectory. By taking the motor / driven wheel 24 at the hinge axes of the connecting rod 111 and the connecting rod 112 as the motor, the motion trajectory curve simulation can be performed. It can be found that the relative distance between the connecting rod 111 and the connecting rod 113 in the relative motion is changing and does not present a linear law. In this way, not only can it be closer to the “rolling + sliding” composite trajectory of the human knee joint in the flexion and extension process, but also the non-equal ratio torque transmission can be realized by controlling the gear speed ratio and the transmission structure, the intelligent control system can be more finely adjusted, and the prosthetic human-machine interaction performance can be improved. The results are as follows Figure 9 and Figure 10 Figure 10 ​(A is the hinge axis of connecting rods III 13 and IV 14, B is the connection point of connecting rods I 15 and II 16, and C is the hinge point of connecting rods I 11 and II 12.) The four-bar linkage 1, combined with the rotating wheel mechanism 2, ensures stable power transmission at any position without slippage or fluctuations due to changes in distance, ultimately achieving a more natural and adaptable gait. Throughout the entire motion process, there is no interference between the various components, resulting in smooth movement without dead spots, sudden speed changes, or sudden angle changes.

[0074] In one embodiment, the transmission ratio between the master / slave wheel 24 and the slave / driving wheel 25 is 1. With this configuration, in the passive mode, the gear train transmission ratio is 1. Since both the master / slave wheel 24 and the slave / driving wheel 25 are free-wheeling shafts with no external load, the structure can be reverse-driven in the passive mode, ensuring the usability of the passive mode.

[0075] The present invention also provides a knee joint motion method, using the above-mentioned knee joint structure, including active knee joint motion and passive knee joint motion;

[0076] The active knee joint movement comprises the following steps:

[0077] The power output drives the master / slave wheel 24 or the slave / driving wheel 25 to rotate, and the master / slave wheel 24 or the slave / driving wheel 25 drives the slave / driving wheel 25 or the master / slave wheel 24 to rotate through the transmission wheel I 23;

[0078] At the same time, the four-bar linkage 1 and the rotating wheel mechanism 2 move in coordination, so that the four-bar linkage 1 moves along a specific trajectory;

[0079] The driven knee joint movement comprises the following steps:

[0080] The connecting rod I 11 or the connecting rod III 13 moves passively, and cooperates with the rotating wheel mechanism 2 during the passive movement to make the four-bar linkage 1 move along a specific trajectory.

[0081] The present invention also provides a robotic leg comprising the aforementioned knee joint structure. The robotic leg is preferably a prosthetic limb, which enables passive movement under human motion. Alternatively, the robotic leg may be an exoskeleton structure of a human leg.

[0082] The present invention also provides an active-passive switching structure 3, comprising a driving wheel 31, a transmission wheel II 32, a driven wheel 33, a bracket 34 and a clutch mechanism;

[0083] The driving wheel 31 and the driven wheel 33 are rotatably arranged on the bracket 34. The driving wheel 31 is used to connect with the rotary drive mechanism 4, thereby realizing the active rotation of the driving wheel 31 and the active movement of the knee joint structure. The driven wheel 33 is used to connect with the driving part of the knee joint structure, that is, the master / driven wheel 24 or the slave / driving wheel 25 of the knee joint structure. Figure 1 The driven wheel 33 is connected to the driven / driving wheel 25;

[0084] The clutch mechanism includes an operating portion and a locking portion. The operating portion includes a rotating member 35 rotatably arranged on the axis of the driving wheel 31, a clutch rod 36 fixedly arranged on the rotating member 35, and the transmission wheel II 32 is rotatably arranged on the clutch rod 36, and the transmission wheel II 32 is always rotated in conjunction with the driving wheel 31. By rotating the clutch rod 36, the transmission wheel II 32 is rotated in conjunction with or separated from the driven wheel 33. Figure 13 When the transmission wheel II 32 rotates with the driven wheel 33, the driving wheel 31, the transmission wheel II 32 and the driven wheel 33 rotate in sequence, thereby realizing the rotational cooperation between the driving wheel 31 and the driven wheel 33. Figure 14 When the transmission wheel II 32 separates from the driven wheel 33, the driving wheel 31 and the driven wheel 33 lose their rotational coordination. At this point, the driven wheel 33 and the master / slave wheel 24 or slave / driving wheel 25 of the knee joint structure lose their load and transition to a free configuration, achieving passive motion of the four-bar linkage 1 and the rotating wheel mechanism 2 in the knee joint structure.

[0085] The locking portion is used to lock the position of the clutch lever 36, maintaining the driving wheel II 32 and the driven wheel 33 in a rotationally engaged state or a disengaged state, thereby achieving high stability of active and passive motions.

[0086] This active-passive switching structure 3 is used to quickly switch between active and passive motion of the knee joint structure. If the rotation drive mechanism 4 of the robotic leg loses power, the knee joint structure can be switched to a passive motion state, allowing it to continue to function as a passive robotic leg (e.g., a prosthetic limb). This makes the knee joint structure a combination of active and passive systems.

[0087] In the active mode, the transmission wheel (gear) is used to achieve high-precision and stable power transmission. In the passive mode, reverse driving is possible without affecting the movement of the four-bar linkage 1 in the knee joint structure, thus forming a complete knee joint transmission chain.

[0088] By coupling the active-passive switching structure 3 of the present invention with the knee joint structure, the robotic leg (prosthesis) can continue to function as a four-link passive robotic leg (prosthesis) even after power is depleted, reducing its dependence on electricity. Simultaneously, it can actively switch states based on different usage scenarios, saving energy and adapting to a wider range of scenarios. This allows users to use the robotic leg (prosthesis) with greater confidence, eliminating the need for range anxiety and improving its adaptability.

[0089] In one embodiment, the locking portion includes a slide plate 37, an elastic member 38 and a locking connecting rod 39;

[0090] The chute plate 37 is fixed relative to the bracket 34 , and an arc-shaped chute 371 is provided on the chute plate 37 , and a slider 310 is slidably provided on the arc-shaped chute 371 , and the convex side of the arc-shaped chute 371 faces the axis of the driving wheel 31 ;

[0091] One end of the locking connecting rod 39 is fixed to the rotating member 35, and the other end intersects with the arc-shaped sliding groove 371 and is located on the concave side of the arc-shaped sliding groove 371;

[0092] One end of the elastic member 38 is fixed to the slider 310 , and the other end is fixed to the end of the locking connecting rod 39 .

[0093] In this embodiment, when the rotating member 35 rotates (driving the clutch lever 36 and thus moving the transmission wheel II 32), the locking connecting rod 39 also moves. Because the other end of the locking connecting rod 39 is located on the concave side of the arcuate slot and is connected to the slider 310 via the elastic member 38, the slider 310 slides within the arcuate slot 371. When the slider 310 slides to the corresponding locked position within the arcuate slot 371, the elastic member 38 continuously applies a pulling force, causing the slider 310 to self-lock in the locked position, thereby locking the clutch lever 36 and the locking clutch lever 36. This achieves a self-locking stability effect.

[0094] In addition, due to the presence of the elastic member 38, when the driving wheel II 32 and the driven wheel 33 are engaged, the elastic member 38 can provide a certain preload force, making the driving wheel II 32 and the driven wheel 33 fit more tightly and preventing them from being separated due to vibration and other reasons. At the same time, during the switching process, the elastic member 38 can absorb the impact, making the switching process smooth.

[0095] In addition, in the active drive state, if the driven wheel 33 encounters excessive resistance (such as an accidental impact), the elastic member 38 can be deformed, allowing the locking connecting rod 39 to have a slight displacement, thereby temporarily separating the transmission wheel II 32 from the driven wheel 33, thereby avoiding hard damage to the mechanism.

[0096] The driving wheel 31 and transmission wheel II 32 are always in a mating state. This arrangement eliminates a clutch link, allowing transmission wheel II 32 to achieve clutching only by connecting and disconnecting with the driven wheel 33. This simplifies the complexity of the clutch mechanism, especially in space-constrained scenarios like robotic legs, and improves structural compactness and reliability.

[0097] In one embodiment, the two ends of the arc-shaped sliding groove 371 are respectively a connection limit position and a separation limit position;

[0098] When the transmission wheel II 32 and the driven wheel 33 change from a separation state to a connection state, the slider 310 actively or passively slides from the separation limit position to the connection limit position. When the transmission wheel II 32 and the driven wheel 33 change from a connection state to a separation state, the slider 310 actively or passively slides from the connection limit position to the separation limit position.

[0099] In this embodiment, the design of the arc-shaped slide groove 371 can make the movement of the slider 310 natural and smooth without any jamming. The two ends of the arc-shaped slide groove 371 are configured as two extreme positions. The arc-shaped track of the arc-shaped Huaao 371 can be used to form a locking point at the end of the arc-shaped slide groove 371, and a natural transition is achieved through arc-shaped sliding.

[0100] In one preferred embodiment, the curvature of the arc-shaped slide groove 371 can be designed to form two adjustment modes:

[0101] One adjustment method involves manually adjusting the clutch lever 36 to switch the transmission wheel II 32 and the driven wheel 33 from a disconnected state to a connected state, or vice versa. Due to the small curvature of the arc-shaped slot 371, the slider 310 will actively (automatically) slide from the disconnected limit position to the connected limit position, or vice versa. In this case, a single adjustment is required to achieve active / passive switching.

[0102] Another adjustment mode is that when the transmission wheel II 32 and the driven wheel 33 are switched from the disengaged state to the connected state or from the connected state to the disengaged state after the clutch lever 36 is manually adjusted, the slider 310 cannot be actively (automatically) slid from the disengaged limit position to the connected limit position or from the connected limit position to the disengaged limit position due to the large arc of the arc-shaped sliding groove 371. The switching can only be achieved by passively sliding the slider 310 by artificial operation. At this time, two adjustment operations are required to complete the active and passive switching. At this time, when used as a prosthesis, the low battery can be adjusted first (at this time, the clutch lever 36 needs to be kept in a specific state), which can be adapted to the user. If the adaptation is good, the user performs the second adjustment (adjusts the slider 310) to complete the final switching. If the user's condition is not good and cannot be adapted, the clutch lever 36 can be released, the knee joint is kept in the original state, the last battery is used to keep the user in a safe state, and rescue can be waited.

[0103] In one embodiment, the elastic member 38 is a spring. The spring structure is simple and reliable, and is convenient to disassemble and assemble, and is convenient to adjust the elastic force and control the adjustment sensitivity.

[0104] In one embodiment, the locking portion further comprises a rotating rod 311.

[0105] One end of the rotating rod 311 is rotationally arranged on the sliding groove plate 37, and the rotation axis is located at the center of the arc-shaped sliding groove 371. The other end is fixedly connected with the slider 310. In this embodiment, by adding the rotating rod 311, the sliding stability of the slider 310 can be improved, and the overall structural reliability can be improved.

[0106] In one embodiment, the active and passive switching structure 3 further comprises a manual operation lever 312 fixed on the rotating member 35, and the manual operation lever 312 is used for manually operating the rotating member 35 to rotate. In this embodiment, the active and passive switching structure 3 is switched manually, which is suitable for the user to actively control according to the battery level when the mechanical leg is used as a prosthesis or an exoskeleton, and the number of electric control can be reduced.

[0107] The application also provides an active and passive switching method, which uses the above-mentioned active and passive switching structure 3 to switch the active movement and the passive movement, and comprises the following steps:

[0108] During active movement, the clutch lever 36 is controlled. Since the clutch lever 36, the rotating member 35, the locking connecting rod 39, and the manual operating lever 312 are an integral part, any one of the components can be operated. If the manual operating lever 312 is provided, the clutch lever 36 can be controlled by the manual operating lever 312. This causes the driving wheel 31, the transmission wheel II 32, and the driven wheel 33 to engage in sequence. The locking portion maintains the engagement of the driving wheel 31, the transmission wheel II 32, and the driven wheel 33. At this time, the rotary drive mechanism 4 drives the driving wheel 31 to rotate, which in turn drives the driven wheel 33 to rotate. The driven wheel 33 drives the driving portion (driven / follower wheel 25) of the knee joint structure.

[0109] During passive movement, the transmission wheel II 32 and the driven wheel 33 are separated by controlling the clutch lever 36, and the locking portion maintains the separation state of the transmission wheel II 32 and the driven wheel 33. At this time, the driving part of the knee joint structure (the slave / driving wheel 25) is disconnected from the rotation drive mechanism 4. The driving part of the knee joint structure (the slave / driving wheel 25) is a free end and is not connected to a load, thereby realizing passive free movement of the knee joint structure.

[0110] The present invention also provides a knee joint system, comprising a knee joint structure and the active-passive switching structure 3;

[0111] The knee joint structure includes a four-bar linkage mechanism 1 and a rotating wheel mechanism 2;

[0112] The four-bar linkage 1 includes a link I 11, a link II 12, a link III 13, and a link IV 14, which are hinged end to end in sequence, wherein the link I 11 is used to connect the thigh of the mechanical leg, and the link III 13 is used to connect the calf of the mechanical leg;

[0113] The rotating wheel mechanism 2 includes a connecting rod V21 and a connecting rod VI22 that are hinged to each other, and a transmission wheel I23 is rotatably provided on the hinge axis of the connecting rod V21 and the connecting rod VI22. A master / driven wheel 24 that is rotatably coordinated with the transmission wheel I23 is rotatably provided on the connecting rod V21, and the master / driven wheel 24 is rotatably provided on the connecting rod I11. A slave / driving wheel 25 that is rotatably coordinated with the transmission wheel I23 is rotatably provided on the connecting rod VI22, and the slave / driving wheel 25 is rotatably provided on the connecting rod III13.

[0114] The axle of the driven wheel 33 of the active / passive switching structure 3 is rotatably connected to the axle of the active / driven wheel 24 or the passive / driving wheel 25 .

[0115] The working principles and effects of the four-bar linkage mechanism 1 and the rotating wheel mechanism 2 provided in this embodiment refer to the above description.

[0116] The present invention combines an active-passive switching structure 3 with a rotating wheel mechanism 2 to achieve switching between active and passive motion of the knee joint structure. This allows the corresponding robotic leg to continue functioning as a passive robotic leg (e.g., a prosthetic limb) even after power is depleted. Unlike conventional active-passive robotic legs, the four-bar linkage 1, rotating wheel mechanism 2, and active-passive switching structure 3 provided by the present invention are compact, highly stable, and meet the space-constrained installation requirements of knee joint installation locations.

[0117] In one embodiment, the knee joint system further includes a rotation drive mechanism 4;

[0118] The rotary drive mechanism 4 includes a motor 41, a gear set 42 and a bevel gear set 43;

[0119] The driving gear of the gear set 42 is fixedly engaged with the rotating shaft of the motor 41, the driven gear is fixedly connected to the driving bevel gear of the bevel gear set 43, and the driven bevel gear of the bevel gear set 43 is fixedly connected to the axle of the driving wheel 31. This rotary drive mechanism 4 allows the motor 41 to be arranged longitudinally, and then the motor 41 can be placed on the upper part of the calf or the lower part of the thigh, thereby ensuring the position of the knee joint.

[0120] The present invention also provides a mechanical leg, which includes the above-mentioned knee joint system.

[0121] The above description is merely an embodiment and does not limit the present invention in any way. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make many possible changes, modifications, or modifications to the technical solution of the present invention into equivalent embodiments with equivalent changes using the technical content disclosed above. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A knee joint structure, characterized in that: It comprises a four-link mechanism (1) and a rotating wheel mechanism (2); The four-bar linkage (1) comprises a link I (11), a link II (12), a link III (13) and a link IV (14) which are hinged in sequence head to tail, wherein the link I (11) is used to connect the thigh of the mechanical leg, and the link III (13) is used to connect the calf of the mechanical leg; The rotating wheel mechanism (2) comprises a connecting rod V (21) and a connecting rod VI (22) which are hinged to each other, a transmission wheel I (23) being rotatably provided on the hinge axis of the connecting rod V (21) and the connecting rod VI (22), a master / slave wheel (24) being rotatably provided on the connecting rod V (21) and cooperating with the transmission wheel I (23), the master / slave wheel (24) being rotatably provided on the connecting rod I (11), a slave / driving wheel (25) being rotatably provided on the connecting rod VI (22) and cooperating with the transmission wheel I (23), the slave / driving wheel (25) being rotatably provided on the connecting rod III (13); The connecting rod III (13) is provided with a connecting rod, and the connecting rod includes a connecting rod I (15), a connecting rod II (16) and a connecting rod III (17) connected in sequence; The connecting rod I (15) and the connecting rod III (17) are parallel to each other, and one end of the connecting rod I (15) is fixed to the connecting rod III (13); The end of the connecting rod III (17) is rotatably arranged to set the driven / driving wheel (25).

2. The knee joint structure according to claim 1, wherein: The projection of the axis of the slave / driving wheel (25) onto the plane of the four-bar linkage (1) is located on the connecting rod III (13).

3. The knee joint structure according to claim 2, wherein: The connecting rod I (15) is coplanar with the plane of the four-bar linkage (1), and the driven / driven wheel (25) is located between the connecting rod I (15) and the connecting rod II (16).

4. The knee joint structure according to any one of claims 1 to 3, wherein: The transmission wheel I (23), the master / driven wheel (24) and the slave / driving wheel (25) are located between the four-bar linkage (1) and the connecting rod V (21) and the connecting rod VI (22).

5. The knee joint structure according to any one of claims 1 to 3, wherein: The rotation axis of the master / driven wheel (24) is coaxial with the articulation axis of the connecting rod I (11) and the connecting rod II (12).

6. The knee joint structure according to any one of claims 1 to 3, wherein: The length of the connecting rod I (11) is 27 mm, the length of the connecting rod II (12) is 80 mm, the length of the connecting rod III (13) is 45 mm, and the length of the connecting rod IV (14) is 45 mm.

7. The knee joint structure according to any one of claims 1 to 2, wherein: The transmission ratio of the master / driven wheel (24) and the slave / driving wheel (25) is 1.

8. A knee joint exercise method, characterized in that: Using the knee joint structure according to any one of claims 1 to 7, comprising active knee joint motion and passive knee joint motion; The active knee joint movement comprises the following steps: The power output drives the master / slave wheel (24) or the slave / driving wheel (25) to rotate, and the master / slave wheel (24) or the slave / driving wheel (25) drives the slave / driving wheel (25) or the master / slave wheel (24) to rotate through the transmission wheel I (23); At the same time, the four-bar linkage (1) and the rotating wheel mechanism (2) move in coordination, so that the four-bar linkage (1) moves along a specific trajectory; The driven knee joint movement comprises the following steps: The connecting rod I (11) or the connecting rod III (13) moves passively, and cooperates with the rotating wheel mechanism (2) during the passive movement to make the four-bar linkage (1) move along a specific trajectory.

9. A mechanical leg, characterized in that: The mechanical leg comprises the knee joint structure according to any one of claims 1-8.

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