Active-passive switching structure, switching method, knee joint system and mechanical leg

Abstract

The invention belongs to the field of mechanical legs, and particularly relates to an active and passive switching structure, a switching method, a knee joint system and a mechanical leg. Wherein the driving and driven switching structure comprises a driving wheel, a transmission wheel II, a driven wheel, a bracket and a clutch mechanism; the driving wheel and the driven wheel are rotationally arranged on the support, the driving wheel is connected with the rotary driving mechanism, and the driven wheel is used for being connected with a driving part of the knee joint structure; the clutch mechanism comprises an operating part and a locking part, the operating part comprises a rotating part rotationally arranged on the axis of the driving wheel and a clutch rod fixedly arranged on the rotating part, the transmission wheel II is rotationally arranged on the clutch rod, and the transmission wheel II and the driven wheel are rotationally matched or separated by rotating the clutch rod. The active-passive switching structure is used for achieving rapid switching of active movement and passive movement of the knee joint structure, and after a rotary driving mechanism of the mechanical leg loses power, the knee joint structure can be switched to be in a passive movement state, so that the mechanical leg can still be used as a passive mechanical leg.

Description

Technical Field

[0001] The present invention belongs to the field of robotic legs, and particularly relates to an active-passive switching structure, a switching method, a knee joint system, and a robotic leg. Background Art

[0002] In the field of lower limb assistive devices such as above-knee prosthetics and powered exoskeletons, an active knee joint system that uses a rotary drive mechanism such as a motor to provide power can significantly improve the mobility and gait naturalness of users. However, the operation of such systems highly depends on the power supply. When the power runs out or the drive system fails (i.e., the "power-off" state), the prosthetic limb or exoskeleton usually faces two dilemmas: one is that the entire knee joint structure is completely locked or fails, resulting in the user's movement being blocked or even falling, and the user has to face the embarrassment and danger of "stopping immediately when the power is off"; the other is that although the knee joint can still bend passively, the traditional power transmission path is not effectively disconnected or the load is not released. Even when the drive mechanism stops outputting, the internal gear meshing resistance, motor electromagnetic damping, etc. may still be converted into significant joint movement resistance ("drag"), resulting in a heavy, stiff, and unnatural passive swing, greatly consuming the user's physical energy, making it difficult to achieve smooth and efficient passive walking (such as the natural swing of the stump driving the lower leg), and exacerbating the user's "range anxiety", making them constantly worry about the battery level during use, restricting the activity range and daily application scenarios (such as long-distance outings, emergency evacuations, etc.).

[0003] In addition, the existing structures for realizing the active / passive mode switching, such as complex electromagnetic clutches, hydraulic separators, or multi-disc friction clutch devices, have problems such as complex structures, large weights, bulky volumes, high costs, slow switching responses, possible residual loads or incomplete separation after switching, and decreased reliability after high-frequency switching or long-term use. These structures are often difficult to be seamlessly integrated into the precise bionic knee joint transmission chain, and may still impose additional mechanical constraints or internal frictional forces on the core transmission components in the separated state (passive mode), hindering the full play of their inherent passive stability mechanism and high-efficiency natural swing characteristics. Therefore, there is an urgent need for an active-passive switching mechanism with a compact structure, reliable operation, fast and thorough switching, and zero obstruction or minimal resistance to the passive movement path. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a main - passive switching structure, a switching method, a knee joint system and a robotic leg, which can efficiently couple or decouple a rotary drive source and a knee joint actuator (especially an optimized knee joint structure incorporating a four - bar linkage and a gear constraint chain), ensuring accurate and stable power transmission in the active mode; while in the passive mode, it is necessary to ensure complete physical disconnection between the drive source (including its inherent resistance) and the actuator chain of the knee joint (such as the main / driven wheel, the driven / active wheel), enabling the latter to achieve completely free, low - resistance, and smooth passive flexion and extension movements based on the biomechanical characteristics of its own structure and the external force of the user, truly achieving the goal that the knee joint can still be used as a high - performance passive joint in the "power - off" or power - saving state, thereby significantly enhancing the environmental adaptability, endurance of the device, and the psychological sense of security and overall comfort of the user.

[0005] The present invention provides a main - passive switching structure, including a driving wheel, a transmission wheel II, a driven wheel, a bracket and a clutch mechanism; The driving wheel and the driven wheel are rotatably arranged on the bracket. The driving wheel is used to connect with a rotary drive mechanism, and the driven wheel is used to connect with the driving part of the knee joint structure; The clutch mechanism includes an operating part and a locking part. The operating part includes a rotating part rotatably arranged on the axis of the driving wheel, a clutch rod fixedly arranged on the rotating part. The transmission wheel II is rotatably arranged on the clutch rod, and the transmission wheel II always rotates in cooperation with the driving wheel. By rotating the clutch rod, the transmission wheel II rotates in cooperation with or separates from the driven wheel. The locking part is used to lock the position of the clutch rod to maintain the state of the transmission wheel II rotating in cooperation with or separating from the driven wheel.

[0006] Furthermore, the locking part includes a chute plate, an elastic member and a locking connecting rod; The chute plate is relatively fixed to the bracket. An arc - shaped chute is arranged on the chute plate. A slider is slidably arranged on the arc - shaped chute, and the convex side of the arc - shaped chute faces the axis of the driving wheel; One end of the locking connecting rod is fixed on the rotating part, and the other end intersects with the arc - shaped chute and is located on the concave side of the arc - shaped chute; One end of the elastic member is fixed to the slider, and the other end is fixed to the end of the locking connecting rod.

[0007] Furthermore, the two ends of the arc - shaped chute are respectively a connection limit position and a separation limit position; When the second driving wheel and the driven wheel change from the separated state to the connected state, the slider slides from the separation limit position to the connection limit position actively or passively. When the second driving wheel and the driven wheel change from the connected state to the separated state, the slider slides from the connection limit position to the separation limit position actively or passively.

[0008] Furthermore, the locking part further includes a rotating rod; One end of the rotating rod is rotatably arranged on the chute plate, and the rotation axis is located at the center of the arc chute, and the other end is fixedly connected to the slider.

[0009] Furthermore, the elastic member is a spring.

[0010] Furthermore, the active and passive switching structure further includes a manual operating rod fixed on the rotating member, and the manual operating rod is used to manually operate the rotation of the rotating member.

[0011] The present invention also provides an active and passive switching method, which uses the above active and passive switching structure to switch between active motion and passive motion, and includes the following steps: During active motion, by controlling the clutch rod, the driving wheel, the second driving wheel and the driven wheel are sequentially matched, and the locking part maintains the matching state of the driving wheel, the second driving wheel and the driven wheel. At this time, the rotary drive mechanism drives the driving wheel to rotate, the driving wheel drives the driven wheel to rotate, and the driven wheel realizes the drive of the driving part of the knee joint; During passive motion, by controlling the clutch rod, the second driving wheel and the driven wheel are separated, and the locking part maintains the separated state of the second driving wheel and the driven wheel. At this time, the driving part of the knee joint is disconnected from the rotary drive mechanism.

[0012] The present invention also provides a knee joint system, including a knee joint structure and the above active and passive switching structure; The knee joint structure includes a four-bar mechanism and a rotating wheel mechanism; The four-bar mechanism includes link I, link II, link III and link IV which are sequentially hinged end to end. Among them, link I is used to connect the thigh of the mechanical leg, and link III is used to connect the calf of the mechanical leg; The rotating wheel mechanism includes link V and link VI which are hinged to each other. A driving wheel I is rotatably arranged on the hinge axis of link V and link VI. A main / driven wheel that rotates in cooperation with the driving wheel I is rotatably arranged on link V. The main / driven wheel is fixed on link I. A driven / active wheel that rotates in cooperation with the driving wheel I is rotatably arranged on link VI. The driven / active wheel is fixed on link III; The wheel axle of the driven wheel of the active and passive switching structure is fixedly connected to the wheel axle of the main / driven wheel or the driven / active wheel.

[0013] Furthermore, the knee joint system further includes a rotary drive mechanism; The rotary drive mechanism includes a motor, a gear set, and a bevel gear set; The driving gear of the gear set is fixedly engaged with the motor rotating shaft, the driven gear is fixedly connected to the driving bevel gear of the bevel gear set, and the driven bevel gear of the bevel gear set is fixedly connected to the wheel shaft of the driving wheel.

[0014] The present invention also provides a mechanical leg, and the mechanical leg includes the above knee joint system.

[0015] The beneficial effect of the present invention is that the active and passive switching structure is used to achieve the rapid switching between the active and passive movements of the knee joint structure. After the rotary drive mechanism of the mechanical leg loses power, the knee joint structure can be switched to the passive movement state, so that it can still be used as a passive mechanical leg (such as a prosthetic leg). The knee joint structure is a combination of an active and passive dual system.

[0016] In the active mode, high-precision and stable power transmission is achieved by relying on the transmission wheel (gear). In the passive mode, it can be driven in reverse without affecting the movement of the four-bar mechanism in the knee joint structure, forming a complete knee joint transmission chain.

[0017] By coupling the active and passive switching structure of the present invention with the knee joint structure, the mechanical leg (prosthetic leg) can still be used as a four-bar passive mechanical leg (prosthetic leg) after the electric energy is exhausted, reducing the dependence on electric energy. At the same time, it can actively switch states according to different usage scenarios, saving electric energy usage and adapting to more scenarios. One can use the mechanical leg (prosthetic leg) with more confidence without generating range anxiety, thereby improving the fitness. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Attached Figure 1 is a schematic structural diagram of the knee joint system of the present invention from a first angle; Attached Figure 2 is a schematic structural diagram of the knee joint system of the present invention from a second angle; Attached Figure 3 is a schematic structural diagram of the knee joint structure of the present invention from a first angle; Attached Figure 4 is a schematic structural diagram of the knee joint structure of the present invention from a second angle; Attached Figure 5 is a front view of the knee joint structure of the present invention at the initial angle; Attached Figure 6 is a front view of the knee joint structure of the present invention at the middle angle; Attached Figure 7 is a front view of the knee joint structure of the present invention at the extreme flexion angle; AttachedFigure 8 Schematic diagram of the dimensions of the four-bar linkage mechanism in one embodiment of the present invention; Appendix Figure 9 Motion schematic diagram of the four-bar linkage mechanism in the present invention; Appendix Figure 10 Motion curve graph of the four-bar linkage mechanism in the present invention; Appendix Figure 11 Cooperating schematic diagram of the master-slave switching structure and the rotary drive mechanism in the present invention; Appendix Figure 12 Structural schematic diagram of the master-slave switching structure in the present invention; Appendix Figure 13 Structural schematic diagram when the driving wheel and the driven wheel are connected in the master-slave switching structure of the present invention; Appendix Figure 14 Structural schematic diagram when the driving wheel and the driven wheel are separated in the master-slave switching structure of the present invention.

[0019] In the figure, 1 - four-bar linkage mechanism; 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 - driving wheel Ⅰ; 24 - master / slave wheel; 25 - slave / master wheel; 3 - master-slave switching structure; 31 - driving wheel; 32 - driving wheel Ⅱ; 33 - driven wheel; 34 - bracket; 35 - rotating part; 36 - clutch lever; 37 - chute plate; 371 - arc chute; 38 - elastic part; 39 - locking connecting rod; 310 - slider; 311 - rotating rod; 312 - manual operating rod; 4 - rotary drive mechanism; 41 - motor; 42 - gear set; 43 - bevel gear set. Detailed implementation manners

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0021] It should be noted that all the directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0022] In addition, in the present invention, descriptions such as "first" and "second" are for descriptive purposes only, and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0023] In the present invention, unless otherwise clearly specified and defined, terms such as "connection" and "fixation" shall be understood in a broad sense. For example, "fixation" may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, a physical connection or a wireless communication connection; it may be directly connected, or indirectly connected through an intermediate medium, and may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] In addition, the technical solutions between various embodiments of the present invention can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0025] As shown in the appended Figure 1 - appended Figure 14 figures, the present invention provides a knee joint structure, including a four-bar linkage mechanism 1 and a rotating wheel mechanism 2; The four-bar linkage mechanism 1 includes a link Ⅰ 11, a link Ⅱ 12, a link Ⅲ 13, and a link Ⅳ 14 that are sequentially hinged end to end. Among them, 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. That is, two opposite links in the four-bar linkage mechanism are respectively used to connect the thigh and the calf of the mechanical leg; The rotating wheel mechanism 2 includes a connecting rod V 21 and a connecting rod VI 22 that are hinged to each other. A driving wheel I 23 is rotatably provided on the hinge axis of the connecting rod V 21 and the connecting rod VI 22. A main / driven wheel 24 that rotates in cooperation with the driving wheel I 23 is rotatably provided on the connecting rod V 21. The main / driven wheel 24 is rotatably provided on the connecting rod I 11. A driven / driving wheel 25 that rotates in cooperation with the driving wheel I 23 is rotatably provided on the connecting rod VI 22. The driven / driving wheel 25 is rotatably provided on the connecting rod III 13. That is, the main / driven wheel 24, the driving wheel I 23, and the driven / driving wheel 25 are engaged in sequence, and the movement trajectories are simultaneously restricted by the connecting rod V 21, the connecting rod VI 22, and the four-bar linkage 1. The main / driven wheel 24 can be used as a driving wheel. At this time, the driven / driving wheel 25 is a driven wheel. On the contrary, the main / driven wheel 24 can be used as a driven wheel. At this time, the driven / driving wheel 25 is a driving wheel. The driving wheel can be used to connect with the rotary drive mechanism 4, and then actively drive the driving wheel I 23 and the driven wheel to rotate, driving the four-bar linkage 1 to move according to its specific movement trajectory. The driving wheel can also be separated from the rotary drive mechanism 4. At this time, the main / driven wheel 24, the driving wheel I 23, and the driven / driving wheel 25 will all be driven to rotate passively due to the deformation of the four-bar linkage 1. Both the main / driven wheel 24 and the driven / driving wheel 25 are both driving wheels and driven wheels.

[0026] In the present invention, the four-bar linkage 1 in the knee joint structure is equivalent to a structurally stable main chain, and the rotating wheel mechanism 2 is equivalent to a speed coordination sub-chain. It can not only achieve or even exceed the knee joint structure formed by the traditional five-bar three-gear structure (Chinese invention patent CN103976807B - A prosthetic knee joint of a gear five-bar mechanism) in terms of movement coordination, but also shows excellent optimization effects in terms of passive movement stability, structural bearing capacity, and module redundancy design. In contrast, the traditional five-bar three-gear structure appears single and fragile in the power interruption state. Its force is mainly borne by the three gears, and the concentrated load borne by the three gears is more likely to fail during long-term use or external impacts, reducing the safety and reliability of the system.

[0027] Specifically, after the power system fails or disconnects in the traditional five-link three-gear structure, due to the following reasons: the single system has a large number of connecting rods (in the present invention, six connecting rods are divided into a four-link system and a two-link system, a total of two independent systems), high degrees of freedom; many hinge points, increasing friction pairs; lack of a stabilization component for structural position constraint, the following problems will occur: dead point jamming phenomenon: the multi-link system is prone to getting stuck at mechanical dead points at some angles, lacking inertia and being difficult to pass through, and the passive movement has lower inertia compared to the active movement, so the traditional five-link three-gear structure is more likely to have the dead point jamming phenomenon; instability and swaying: redundant degrees of freedom, unable to stably maintain the relative angles of the connecting rods after losing active control, resulting in loose or swinging structure; path uncertainty: since the movement trajectory depends on the driving of the active force, there is no passive trajectory guidance or closed-loop constraint; high risk of user imbalance: when the user swings only by external force, the control force is insufficient, and there is a risk of falling due to the lack of restraint of the structure. However, for the knee joint structure provided by the present invention, after the active force is disconnected, the four-link mechanism 1 and the rotating wheel mechanism 2 still maintain a synchronous coupling movement relationship, and the system can autonomously maintain the passive movement trajectory; the stability, anti-jitter ability and load balance in the passive state are better, suitable for scenarios with high robustness requirements (such as walking without power, anti-falling, etc.).

[0028] Therefore, the four-link mechanism 1 of the present invention itself constitutes a closed load-bearing path, having 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 two are combined, the load transfer path is shared by multiple paths, significantly improving the anti-impact ability and ultimate load-bearing capacity of the overall structure. After the active force is disconnected, it can rely on the coupling of the four-link mechanism 1 and the rotating wheel mechanism 2 to achieve stable passive gait simulation, significantly superior to the mechanical instability problem of the five-link mechanism under power-off conditions.

[0029] In addition, in the traditional gear four-link mechanism, two or three gears are directly rotatably 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. However, this knee joint structure is optimized for the application scenario of the knee joint. The main / driven wheel 24 and the driven / active 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 Ⅰ23 is independent of the four-link mechanism 1, enabling it to be coupled and constrained with the four-link mechanism 1, achieving excellent kinematic coordination, high anti-impact ability and ultimate load-bearing capacity of the knee joint structure.

[0030] By designing the sizes of the four-link mechanism 1 and the rotating wheel mechanism 2, referring to Figures 8 - 10, it can achieve customized trajectories, generate complex curves that highly coincide with the instantaneous center trajectories of healthy knees and can be dynamically adjusted, exceeding the fitting ability of pure four-bar mechanisms. Ultimately, it makes the gait more natural and efficient, and has stronger adaptability to different terrains such as slopes and stairs.

[0031] It should be noted that in this application, the main / driven wheel 24, the drive wheel I 23, and the driven / driving wheel 25 are preferably gears. However, due to the coupling of the four-bar mechanism 1 and the rotating wheel mechanism 2 to achieve stable passive gait simulation, friction wheels can also be used.

[0032] In one embodiment, a connecting rod is provided on the link III 13, and the connecting rod includes a connecting rod I 15, a connecting rod II 16, and a connecting rod III 17 that are 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 on the link III 13; The driven / driving wheel 25 is rotatably provided at the end of the connecting rod III 17.

[0033] In this embodiment, by setting the connecting rod, on the one hand, the lower leg of the mechanical leg can be connected through the connecting rod I 15 or the connecting rod III 17, so as to make the connection position of the lower leg relatively far away from the four links in the four-bar mechanism 1, avoid the compact area, ensure the movement range of the four-bar mechanism 1, and facilitate the connection with the driven / driving wheel 25. On the other hand, the setting of the connecting rod can extend the force arm and improve the torque transmission efficiency.

[0034] In a preferred embodiment, the end of the connecting rod III 17 is hinged to the end of the link VI 22, thereby realizing the connection between the four links in the four-bar mechanism 1 and the two links in the rotating wheel mechanism 2, greatly improving the load transfer path of the overall structure, enhancing the load capacity, and at the same time improving the structural stability of the overall structure.

[0035] In one embodiment, the projection of the axis of the driven / driving wheel 25 onto the plane of the four-bar mechanism 1 is located on the link III 13. Such a setting can make the movement trajectory of the driven / driving wheel 25 completely equivalent to that when it is directly rotatably provided on the link III 13, without affecting the coupling of the four-bar mechanism 1 and the rotating wheel mechanism 2.

[0036] In one embodiment, the connecting rod Ⅰ15 is coplanar with the plane of the four-bar linkage 1, and the slave / driving wheel 25 is located between the connecting rod Ⅰ15 and the connecting rod Ⅱ16. Such a configuration can stably and reliably fix the slave / driving wheel 25. The two rigid rods of the connecting rod Ⅰ15 and the connecting rod Ⅱ16 can constitute a protective bracket for the slave / driving wheel 25. Preferably, the slave / driving wheel 25 can be connected to the ends of the connecting rod Ⅰ15 and the connecting rod Ⅱ16 away from the connecting rod Ⅲ13 at the same time, or the slave / driving wheel 25 can be connected to the connecting rod Ⅱ16 and the connecting rod Ⅲ13 at the same time, so that the slave / driving wheel 25 is a double-point fixed structure, which greatly improves the rotation stability of the slave / driving wheel 25.

[0037] In one embodiment, the transmission wheel I 23 , the master / slave wheel 24 and the slave / driving wheel 25 are located between the four-bar linkage 1 and the connecting rods V 21 and VI 22 .

[0038] In this embodiment, the three wheels are located between the two groups of rods, so that the overall structure is compact, and the two groups of rods constitute physical protection for the wheels.

[0039] In one embodiment, the rotation axis of the driving / driven wheel 24 is coaxial with the articulation axis of the connecting rod Ⅰ11 and the connecting rod Ⅱ12.

[0040] This setting not only ensures that the connecting rod rotation and gear drive are completely synchronized, improving motion consistency and transmission efficiency, but also greatly simplifies the structure, shortens the torque transmission path, better resists knee bending and deflection torque, and enhances structural rigidity and stability. Especially in passive mode, the structure can stably respond to external force drive to avoid swing out of control or load transmission imbalance.

[0041] In one embodiment, 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. Figures 3 - 10 After the four-bar linkage 1 is coupled with the rotating wheel mechanism 2, a specific motion trajectory can be achieved. By using the master / slave wheel 24 at the hinge axis of the connecting rod Ⅰ11 and the connecting rod Ⅱ12 as the driving wheel, the motion trajectory curve is simulated. It can be found that the relative distance between the connecting rod Ⅰ11 and the connecting rod Ⅲ13 in the relative motion is changing and does not show a linear law. Such a setting is not only closer to the "rolling + sliding" composite trajectory of the human knee joint during flexion and extension, but also can realize non-equiproportional torque transmission by controlling the gear ratio and transmission structure. The auxiliary intelligent control system can be adjusted more finely to improve the human-computer interaction performance of the prosthesis. The results are shown in Figure 9 and Figure 10 ( Figure 10In it, A is the hinge axis of connecting rod Ⅲ13 and connecting rod Ⅳ14, B is the connection point of connecting rod Ⅰ15 and connecting rod Ⅱ16, and C is the hinge point of connecting rod Ⅰ11 and connecting rod Ⅱ12). That is, the four-bar linkage 1 cooperates with the rotating wheel mechanism 2, which can maintain the stable transmission of power at any position, and will not slip or change due to the change of distance, etc., and can realize the stable output of power. Finally, a more natural and adaptable gait is achieved. During the whole process of movement, there will be no movement interference between components, the movement is smooth, and there are no dead points, sudden speed changes, and sudden angle changes, etc.

[0042] In one embodiment, the transmission ratio of the master / slave wheel 24 and the slave / master wheel 25 is 1. With this setting, in the passive mode, the transmission ratio of the gear train is 1. Since both the master / slave wheel 24 and the slave / master wheel 25 are free rotating shafts and there is no external load, this structure can be driven in reverse in the passive mode, ensuring the usability of the passive mode.

[0043] The present invention also provides a knee joint movement method, using the above knee joint structure, including active knee joint movement and passive knee joint movement; The active knee joint movement includes the following steps: Power output drives the master / slave wheel 24 or the slave / master wheel 25 to rotate, and the master / slave wheel 24 or the slave / master wheel 25 drives the slave / master wheel 25 or the master / slave wheel 24 to rotate through the transmission wheel Ⅰ23; 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 performs a specific trajectory movement; The passive knee joint movement includes the following steps: The connecting rod Ⅰ11 or the connecting rod Ⅲ13 moves passively, and during the passive movement, it cooperates with the rotating wheel mechanism 2, so that the four-bar linkage 1 performs a specific trajectory movement.

[0044] The present invention also provides a mechanical leg, and the mechanical leg includes the above knee joint structure. Among them, the mechanical leg is preferably a prosthetic limb, and thus realizes passive movement under the movement of the human body. It can also be an exoskeleton structure of the human leg.

[0045] The present invention also provides a master-slave switching structure 3, including a driving wheel 31, a transmission wheel Ⅱ32, a driven wheel 33, a bracket 34 and a clutch mechanism; 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 driving mechanism 4, so as to realize the driving rotation of the driving wheel 31 and realize 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 / slave wheel 24 or the slave / master wheel 25 of the knee joint structure, Figure 1 For the driven wheel 33 to be connected with the slave / master wheel 25; The clutch mechanism includes an operating part and a locking part. The operating part includes a rotating member 35 rotatably arranged on the axis of the driving wheel 31, and a clutch rod 36 fixedly arranged on the rotating member 35. The second transmission wheel 32 is rotatably arranged on the clutch rod 36, and the second transmission wheel 32 is always in rotational cooperation with the driving wheel 31. By rotating the clutch rod 36, the second transmission wheel 32 is brought into rotational cooperation or separation with the driven wheel 33. Refer to Figure 13 , when the second transmission wheel 32 is in rotational cooperation with the driven wheel 33, the driving wheel 31, the second transmission wheel 32 and the driven wheel 33 are in rotational cooperation in sequence, so as to realize the rotational cooperation between the driving wheel 31 and the driven wheel 33. Refer to Figure 14 , when the second transmission wheel 32 is separated from the driven wheel 33, the driving wheel 31 and the driven wheel 33 are disconnected from rotational cooperation. At this time, the driven wheel 33 loses the load with the main / driven wheel 24 or the driven / main wheel 25 of the knee joint structure and becomes a free structure, realizing the passive movement of the four-bar linkage mechanism 1 and the rotating wheel mechanism 2 in the knee joint structure.

[0046] The locking part is used to lock the position of the clutch rod 36, maintaining the rotational cooperation state or the separated state between the second transmission wheel 32 and the driven wheel 33, thereby realizing high stability of the active movement and the passive movement.

[0047] This active / passive switching structure 3 is used to realize the rapid switching between the active and passive movements of the knee joint structure. After the rotary drive mechanism 4 of the robotic leg loses power, the knee joint structure can be switched to the passive movement state, so that it can still be used as a passive robotic leg (such as a prosthetic limb). The knee joint structure is a combination of an active and a passive dual system.

[0048] In the active mode, high-precision and stable power transmission is achieved by relying on the transmission wheel (gear). In the passive mode, it can be driven in reverse without affecting the movement of the four-bar linkage mechanism 1 in the knee joint structure, forming a complete knee joint transmission chain.

[0049] By coupling the active / passive switching structure 3 of the present invention with the knee joint structure, the robotic leg (prosthetic limb) can still be used as a four-bar passive robotic leg (prosthetic limb) after the electric energy is exhausted, reducing the dependence on electric energy. At the same time, it can actively switch states according to different usage scenarios, saving electric energy usage and adapting to more scenarios. One can use the robotic leg (prosthetic limb) with more confidence without having to worry about battery life, thus improving the suitability.

[0050] In one embodiment, the locking part includes a chute plate 37, an elastic member 38 and a locking connecting rod 39; The chute plate 37 is relatively fixed to the bracket 34. An arc chute 371 is provided on the chute plate 37. A slider 310 is slidably arranged on the arc chute 371, and the convex side of the arc chute 371 faces the axis of the driving wheel 31; One end of the locking connecting rod 39 is fixed to the rotating member 35, and the other end intersects with the arc chute 371 and is located on the concave side of the arc chute 371; 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.

[0051] In this embodiment, when the rotating member 35 rotates (driving the clutch rod 36 and thus moving the transmission wheel II 32), the locking connecting rod 39 also moves accordingly. Since the other end of the locking connecting rod 39 is on the concave side of the arc chute and is connected to the slider 310 through the elastic member 38, the slider 310 slides in the arc chute 371. The slider 310 slides into the corresponding locking position in the arc chute 371. At this time, the elastic member 38 always provides a pulling force to lock the slider 310 in the locking position, realizing the position locking of the clutch rod 36 and the locking clutch rod 36. The self-locking stability effect is achieved.

[0052] In addition, due to the existence of the elastic member 38, when the transmission wheel II 32 meshes with the driven wheel 33, the elastic member 38 can provide a certain pre-tightening force to make the cooperation between the transmission wheel II 32 and the driven wheel 33 closer, avoiding disengagement due to vibration or other reasons. At the same time, during the switching process, the elastic member 38 can absorb shocks to make the switching process smooth.

[0053] In addition, in the active driving state, if the driven wheel 33 encounters excessive resistance (such as accidental impact), the elastic member 38 can deform, allowing the locking connecting rod 39 to have a small displacement, and then temporarily separating the transmission wheel II 32 from the driven wheel 33, thereby avoiding hard damage to the mechanism.

[0054] Among them, the driving wheel 31 and the transmission wheel II 32 are always in a cooperative state. Such a setting can reduce a clutch link, enabling the transmission wheel II 32 to realize the clutch function only by connecting and disconnecting with the driven wheel 33. The complexity of the clutch mechanism is simplified. Especially in a scenario with limited space such as a robotic leg, the structural compactness and reliability can be improved.

[0055] In one embodiment, the two ends of the arc chute 371 are respectively a connection limit position and a separation limit position; When the second driving wheel 32 and the driven wheel 33 change from the separated state to the connected state, the slider 310 actively or passively slides from the separation limit position to the connection limit position. When the second driving wheel 32 and the driven wheel 33 change from the connected state to the separated state, the slider 310 actively or passively slides from the connection limit position to the separation limit position.

[0056] In this embodiment, the design of the arc-shaped chute 371 enables the movement of the slider 310 to be natural and smooth without jamming. By configuring the two ends of the arc-shaped chute 371 as two limit positions, the arc-shaped track of the arc-shaped chute 371 can be used to form a locking point at the end of the arc-shaped chute 371, and the arc-shaped sliding provides a natural transition.

[0057] In one preferred embodiment, by designing the curvature of the arc-shaped chute 371, two adjustment methods can be formed respectively: One adjustment method is that after manually adjusting the clutch lever 36, when the second driving wheel 32 and the driven wheel 33 change from the separated state to the connected state, or when the second driving wheel 32 and the driven wheel 33 change from the connected state to the separated state, due to the small curvature of the arc-shaped chute 371, the slider 310 will actively (automatically) slide from the separation limit position to the connection limit position, or from the connection limit position to the separation limit position. At this time, only one adjustment is required to achieve the active-passive switching.

[0058] Another adjustment method is that after manually adjusting the clutch lever 36, when the second driving wheel 32 and the driven wheel 33 change from the separated state to the connected state, or when the second driving wheel 32 and the driven wheel 33 change from the connected state to the separated state, due to the large curvature of the arc-shaped chute 371, the slider 310 cannot actively (automatically) slide from the separation limit position to the connection limit position, or from the connection limit position to the separation limit position. Only by manually sliding the slider 310 passively can the switching be completed. At this time, two adjustment operations are required to complete the active-passive switching. At this time, when used as a prosthetic limb, when the battery power is low, the first adjustment can be made first (at this time, the clutch lever 36 needs to be kept in a specific state continuously), which can be used for the user to adapt. If the adaptation is good, the user then makes the second adjustment (adjusting the slider 310) to complete the final switching. If the user's condition is not good and they cannot adapt, the clutch lever 36 can be released to keep the knee joint in its original state, and the remaining battery power can be used to keep themselves in a safe state and wait for rescue.

[0059] In one embodiment, the elastic member 38 is a spring. The spring structure is simple and reliable, and it is convenient to disassemble and assemble, and it is convenient to adjust the elastic force, thereby controlling the adjustment sensitivity. In one embodiment, the locking portion further includes a rotating rod 311; One end of the rotating rod 311 is rotatably arranged on the sliding groove plate 37, and the rotation axis is located at the center of the arc-shaped sliding groove 371, and the other end is fixedly connected to 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.

[0060] In one embodiment, the active and passive switching structure 3 further includes a manual operating rod 312 fixed on the rotating member 35, and the manual operating rod 312 is used to manually operate the rotation of the rotating member 35. In this embodiment, the active and passive switching structure 3 is manually switched, which is suitable for the user to actively control according to the power when the robotic leg is used as a prosthetic limb or an exoskeleton, and the number of electric controls can be reduced.

[0061] The present invention also provides an active and passive switching method, which uses the above-mentioned active and passive switching structure 3 to switch between active movement and passive movement, and includes the following steps: During active movement, by controlling the clutch rod 36, since the clutch rod 36, the rotating member 35, the locking connecting rod 39 and the manual operating rod 312 are an integral part, any of the components can be operated. When the manual operating rod 312 is provided, the clutch rod 36 can be controlled by the manual operating rod 312. Make the driving wheel 31, the transmission wheel II 32 and the driven wheel 33 cooperate in sequence, and the locking part maintains the cooperation state of the driving wheel 31, the transmission wheel II 32 and the driven wheel 33. At this time, the rotation driving mechanism 4 drives the driving wheel 31 to rotate, the driving wheel 31 drives the driven wheel 33 to rotate, and the driven wheel 33 realizes the driving of the driving part (slave / driving wheel 25) of the knee joint structure; During passive movement, by controlling the clutch rod 36, the transmission wheel II 32 and the driven wheel 33 are separated, and the locking part maintains the separated state of the transmission wheel II 32 and the driven wheel 33. At this time, the driving part (slave / driving wheel 25) of the knee joint structure is disconnected from the rotation driving mechanism 4, and the driving part (slave / driving wheel 25) of the knee joint structure is a free end and is not connected to a load, and the passive free movement of the knee joint structure can be realized.

[0062] The present invention also provides a knee joint system, including a knee joint structure and the above-mentioned active and passive switching structure 3; The knee joint structure includes a four-bar linkage mechanism 1 and a rotating wheel mechanism 2; The four-bar linkage mechanism 1 includes a link I 11, a link II 12, a link III 13 and a link IV 14 that are sequentially hinged end to end, wherein the link I 11 is used to connect the thigh of the robotic leg, and the link III 13 is used to connect the calf of the robotic leg; The rotating wheel mechanism 2 includes a connecting rod V 21 and a connecting rod VI 22 that are hinged to each other. A driving wheel I 23 is rotatably arranged on the hinge axis of the connecting rod V 21 and the connecting rod VI 22. A main / driven wheel 24 that rotates in cooperation with the driving wheel I 23 is rotatably arranged on the connecting rod V 21. The main / driven wheel 24 is rotatably arranged on the connecting rod I 11. A driven / active wheel 25 that rotates in cooperation with the driving wheel I 23 is rotatably arranged on the connecting rod VI 22. The driven / active wheel 25 is rotatably arranged on the connecting rod III 13.

[0063] The wheel axle of the driven wheel 33 of the main passive switching structure 3 is rotatably connected to the wheel axle of the main / driven wheel 24 or the driven / active wheel 25.

[0064] For the working principle and effects of the four-bar linkage 1 and the rotating wheel mechanism 2 provided in this embodiment, refer to the above description.

[0065] In the present invention, the main passive switching structure 3 is combined with the rotating wheel mechanism 2, which can realize the switching between the active movement and the passive movement of the knee joint structure. So that the corresponding mechanical leg can still be used as a passive mechanical leg (such as a prosthetic limb) after the battery runs out. Different from the conventional main passive mechanical leg, the four-bar linkage 1, the rotating wheel mechanism 2 and the main passive switching structure 3 provided in the present invention can be small in size, compact in structure and high in stability, meeting the installation requirements with limited space at the knee joint installation position.

[0066] In one of the embodiments, the knee joint system further includes a rotary drive mechanism 4; The rotary drive mechanism 4 includes a motor 41, a gear set 42 and a bevel gear set 43; The driving gear of the gear set 42 is fixedly fitted 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 wheel axle of the driving wheel 31. This rotary drive mechanism 4 can arrange the motor 41 longitudinally, and then place the motor 41 on the upper part of the calf or the lower part of the thigh, so as to ensure the knee joint position.

[0067] The present invention also provides a mechanical leg, which includes the above knee joint system.

[0068] The above is only this embodiment and does not impose any limitation on the present invention. Any person skilled in the art can make many possible changes, modifications or equivalent changes to the technical solution of the present invention by using the technical content disclosed above without departing from the scope of the technical solution of the present invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to 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 main and passive switching structure, characterized in that It includes a driving wheel (31), a transmission wheel II (32), a driven wheel (33), a bracket (34) and a clutch mechanism; 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 driving mechanism (4), and the driven wheel (33) is used to connect with the driving part of the knee joint structure; The clutch mechanism includes an operating part and a locking part. The operating part includes a rotating part (35) rotatably arranged on the axis of the driving wheel (31), and a clutch rod (36) fixedly arranged on the rotating part (35). The transmission wheel II (32) is rotatably arranged on the clutch rod (36), and the transmission wheel II (32) is always in rotational cooperation with the driving wheel (31). By rotating the clutch rod (36), the transmission wheel II (32) is brought into rotational cooperation or separation with the driven wheel (33). The locking part is used to lock the position of the clutch rod (36) to maintain the rotational cooperation state or separation state between the transmission wheel II (32) and the driven wheel (33).

2. The master-slave switching structure according to claim 1, characterized in that, The locking part includes a chute plate (37), an elastic part (38) and a locking connecting rod (39); The chute plate (37) is relatively fixed to the bracket (34). An arc chute (371) is arranged on the chute plate (37). A slider (310) is slidably arranged on the arc chute (371), and the convex side of the arc chute (371) faces the axis of the driving wheel (31); One end of the locking connecting rod (39) is fixed on the rotating part (35), and the other end intersects with the arc chute (371) and is located on the concave side of the arc chute (371); One end of the elastic part (38) is fixed to the slider (310), and the other end is fixed to the end of the locking connecting rod (39).

3. The master-slave switching structure according to claim 2, characterized in that, The two ends of the arc chute (371) are respectively a connection limit position and a separation limit position; When the transmission wheel II (32) and the driven wheel (33) change from the separation state to the 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 the connection state to the separation state, the slider (310) actively or passively slides from the connection limit position to the separation limit position.

4. The master-slave switching structure according to claim 2, characterized in that, The locking part further includes a rotating rod (311); One end of the rotating rod (311) is rotatably arranged on the chute plate (37), and the rotation axis is located at the center of the arc chute (371). The other end is fixedly connected to the slider (310).

5. The master-slave switching structure according to claim 2, characterized in that, The elastic part (38) is a spring.

6. The master-slave switching structure according to any one of claims 1-5, characterized in that It further includes a manual operating rod (312) fixed on the rotating part (35), and the manual operating rod (312) is used to manually operate the rotation of the rotating part (35).

7. A method for active-passive switching, characterized in that Using the master-slave switching structure (3) according to any one of claims 1-5 to switch between active movement and passive movement, includes the following steps: During active movement, by controlling the clutch lever (36), the driving wheel (31), the second transmission wheel (32) and the driven wheel (33) are sequentially engaged, and the locking portion maintains the engaged state of the driving wheel (31), the second transmission wheel (32) and the driven wheel (33). At this time, the rotary drive mechanism (4) drives the driving wheel (31) to rotate, the driving wheel (31) drives the driven wheel (33) to rotate, and the driven wheel (33) drives the driving part of the knee joint; During passive movement, by controlling the clutch lever (36), the second transmission wheel (32) and the driven wheel (33) are separated, and the locking portion maintains the separated state of the second transmission wheel (32) and the driven wheel (33). At this time, the driving part of the knee joint is disconnected from the rotary drive mechanism (4).

8. A knee joint system, characterized in that, It includes a knee joint structure and the active / passive switching structure (3) according to any one of claims 1-5; The knee joint structure includes a four-bar linkage mechanism (1) and a rotating wheel mechanism (2); The four-bar linkage mechanism includes a link I (11), a link II (12), a link III (13) and a link IV (14) that are sequentially hinged end to end. Among them, 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) includes a link V (21) and a link VI (22) that are hinged to each other. A first transmission wheel (23) is rotatably provided on the hinge axis of the link V (21) and the link VI (22). A main / driven wheel (24) that is rotationally matched with the first transmission wheel (23) is rotatably provided on the link V (21). The main / driven wheel (24) is fixed on the link I (11). A driven / active wheel (25) that is rotationally matched with the first transmission wheel (23) is rotatably provided on the link VI (22). The driven / active wheel (25) is fixed on the link III (13); The wheel axle of the driven wheel (33) of the active / passive switching structure (3) is fixedly connected to the wheel axle of the main / driven wheel (24) or the driven / active wheel (25).

9. The knee joint system according to claim 8, characterized in that, It further includes a rotary drive mechanism (4); The rotary drive mechanism (4) includes a motor (41), a gear set (42) and a bevel gear set (43); The driving gear of the gear set (42) is fixedly fitted 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 wheel axle of the driving wheel (31).

10. A mechanical leg, characterized in that, The mechanical leg includes the knee joint system according to any one of claims 8-9.

Images