Knee-ankle dynamic coupling thigh and lower limb prosthesis

Abstract

The invention relates to a knee-ankle dynamic coupling thigh and lower limb prosthesis which comprises a joint connecting piece, a knee-ankle dynamic coupling joint, an ankle joint, a self-locking mechanism, a parallel spring mechanism, a raspberry Pi controller, an IMU inertial measurement sensor and a driving rope pre-tightening mechanism, and the joint connecting piece comprises a knee joint upper standard connector, a knee joint connecting piece and a knee-ankle joint connecting piece; the knee-ankle dynamic coupling joint comprises a fixed plate, a transmission shaft, a motor and a synchronous pulley; the ankle joint comprises an ankle joint upper standard connector, an ankle joint upper connecting piece, an ankle joint lower connecting piece, a strain gauge, an extension spring and a carbon fiber foot plate. The self-locking mechanism comprises a locking mechanism upper large rocker, a pressing self-locking mechanism, a right-angle connecting rod, a special-shaped rocker and a short shaft. The parallel spring mechanism comprises a sliding block, a spring and a guide rail. The knee-ankle dynamic coupling joint and the ankle joint are adopted. Different power outputs are carried out in different walking scenes. And a lower reduction ratio and a speed bump are adopted for transmission, so that the reverse driving performance of the joint is effectively improved.

Description

Technical Field

[0001] The invention relates to a thigh lower limb prosthesis with knee-ankle power coupling. Background Art

[0002] With the advancement of science and technology, the powered lower limb prostheses developed for patients with lower limb amputations have gradually changed from passive to active. Their powered lower limb prostheses can provide power for human walking, improve the walking comfort of amputees and adapt to more walking scenarios. At present, powered lower limb prostheses still have some shortcomings in design and function, and it is difficult to balance sufficient power, light weight and comfortable wearing. In response to the above problems, the present invention innovatively proposes the concept of knee-ankle power coupling and designs a corresponding mechanism. Thereby, the weight of the powered lower limb prosthesis is reduced and the overall joint torque is improved. At the same time, synchronous belt transmission and rope drive are used to reduce movement noise and improve the wearing comfort of prosthesis wearers.

[0003] Existing powered prosthetic knee joints, designed to meet the daily walking needs of amputees, typically utilize a single high-torque motor to address high-torque requirements for situations like ascending and descending stairs. These prosthetic knee joints are typically large, have high deceleration ratios, poor backdrive performance, and high overall joint mass. Summary of the Invention

[0004] The purpose of the present invention is to provide a knee-ankle power-coupled thigh lower limb prosthesis. The present invention adopts a modular design and can be customized for prosthetic patients. The present invention can provide sufficient power for human walking. At the same time, the present invention innovatively adopts knee-ankle power-coupled joints and ankle joints. Different power outputs are performed for different walking scenarios. The use of a lower reduction ratio and speed reduction belt transmission effectively improves the joint's anti-drive performance and reduces its movement noise. At the same time, it has a compact structure, light weight, small size, long battery life, and low power consumption.

[0005] The knee-ankle powered coupled thigh lower limb prosthesis proposed in the present invention includes a joint connector, a knee-ankle powered coupled joint, an ankle joint, a self-locking mechanism, a parallel spring mechanism, a Raspberry Pi controller 6, an IMU inertial measurement sensor 9, a drive rope pre-tensioning mechanism, and a rope drive system, wherein: The rope drive system includes an ankle joint reel 12, an ankle joint drive rope 13, a spring-loaded drive rope 16, a locking mechanism drive rope 27, a spring-loaded drive rope 33, and a coil disk 47. The ankle joint reel 12 is mounted on the ankle joint drive rope 13. The coil disk 47 is provided with three parallel spherical coil grooves, which are connected to the ankle joint drive rope 13, the locking mechanism drive rope 27, and the spring-loaded drive rope 33, respectively. The joint connector includes a receiving cavity connector 1, a standard upper knee joint 2, a right upper knee joint connector 3, a knee-ankle joint connector 7 and a left upper knee joint connector 14. The receiving cavity connector 1 is fixed to the upper part of the standard upper knee joint 2 by bolts. The right upper knee joint connector 3 and the left upper knee joint connector 14 are respectively fixed to both sides of the standard upper knee joint 2 by bolts. The right upper knee joint connector 3 and the left upper knee joint connector 14 are both provided with bearing mounting bosses on the inner sides, and the axes are collinear; a fixing plate 4 is provided between the right upper knee joint connector 3 and the left upper knee joint connector 14, and a bearing mounting hole is provided on the fixing plate 4. The right upper knee joint connector 3 and the left upper knee joint connector 14 are connected to the fixing plate 4 by bearings to form a revolute pair; The knee-ankle power coupling joint includes a fixing plate 4, a transmission shaft 20, a large joint motor 5, a small joint motor 22, a synchronous belt 17, a large synchronous pulley 15 and a small synchronous pulley 21; the large synchronous pulley 15 is fixed to the fixing plate 4 through a bearing, and the base of the transmission shaft 20 is fixedly connected to the large joint motor 5 by bolts; the cross-section of the end of the transmission shaft 20 away from the large joint motor 5 is hexagonal, and the center hole of the small synchronous pulley 21 passes through the hexagonal cross-section, so that the small synchronous pulley 21 and the transmission shaft 20 can rotate synchronously; the large synchronous pulley 15 is respectively connected to the upper connector of the knee joint The right 3 and the left upper connector 14 of the knee joint are fixedly connected, and the axis of the large synchronous pulley 15 is collinear with the axis of the right upper connector 3 and the left upper connector 14 of the knee joint; the end faces of the large synchronous pulley 15 and the small synchronous pulley 21 are kept in the same plane, and the large synchronous pulley 15 and the small synchronous pulley 21 are connected by a synchronous belt 17; when the shaft of the large joint motor 5 rotates, it can drive the large synchronous pulley 15 to rotate in the same direction, thereby driving the fixed plate 4 to rotate around the axis of the right upper connector 3 and the left upper connector 14 of the knee joint to achieve flexion and extension of the knee joint; The ankle joint includes a standard ankle joint joint 42, a left ankle joint connector 43, a right ankle joint connector 8, a lower ankle joint connector 44, a strain gauge 45, a tension spring 46 and a carbon fiber foot plate 10. The carbon fiber foot plate 10 is affixed with strain gauges 45 on the top front side and the bottom of the arch. The strain gauge 45 is connected to the IMU inertial measurement sensor 9 to detect whether the carbon fiber foot plate 10 is in contact with or separated from the ground; the carbon fiber foot plate 10 is connected to the lower ankle joint connector 44 through the foot plate connector 11. Horizontal protruding shaft end surfaces are provided on both sides of the lower ankle joint connector 44 for mounting bearings. The lower ankle joint connector 44 is connected to the right ankle joint connector 8 and the left ankle joint connector 43 through the bearings on both sides to form a revolute pair; the ankle joint A rectangular space is provided in the middle of the lower portion 44 of the upper connector, and the ankle joint pulley 12 is placed in the middle of the rectangle and fixedly connected by bolts; the tops of the right ankle joint connector 8 and the left ankle joint connector 43 are fixedly connected to the standard ankle joint connector 42 by bolts respectively; the ankle joint pulley 12 is driven by the ankle joint driving rope 13 to rotate around the axis of the center hole of the right ankle joint connector 8 and the left ankle joint connector 43, thereby driving the carbon fiber foot plate 10 to rotate around the axis of the center hole of the right ankle joint connector 8 and the left ankle joint connector 43; one end of the tension spring 46 is connected to the fixed shaft on one side of the ankle joint pulley 12, and the other end is fixed to the right ankle joint connector 8. During the plantar flexion of the ankle joint, the tension spring 46 will be stretched; The self-locking mechanism includes a large rocker 19 on the locking mechanism, a press self-locking mechanism 37, a right-angle connecting rod 38, an upper special-shaped rocker 39, a lower special-shaped rocker 40 and a short shaft 41; the upper large rocker 19 of the locking mechanism is provided with a through hole on a vertical horizontal plane at one end away from the rotation axis, and a short shaft 41 is installed in the through hole, and the protruding height of the short shaft 41 is not higher than the upper special-shaped rocker 39; that is, the upper special-shaped rocker 39 will contact the short shaft 41 when it rotates around the rotation axis; the bottom of the upper special-shaped rocker 39 is fixed to the lower special-shaped rocker 40 by the rotation axis. The special-shaped rocker lower 40 is fixedly connected. During the rotation process, it will contact the protruding cylinder in the middle of the large rocker 19 on the locking mechanism within a specified angle range; the special-shaped rocker upper 39 is provided with a rotation axis on the side away from the short axis 41. The special-shaped rocker upper 39 can form a rotation pair with the small rocker 18 on the locking mechanism, so that the small rocker 18 on the locking mechanism rotates around its rotation axis; the other side of the small rocker 18 on the locking mechanism forms a rotation pair with the right-angle connecting rod 38, and the right-angle connecting rod 38 is fixedly connected to the telescopic rod of the press self-locking mechanism 37; The parallel spring mechanism includes a slider 29, a lower slider connector 30, a middle slider connector 31, a rectangular spring 32, a guide rail 34 and an upper slider connector 35. There are three sliders 29; the two ends of the rectangular spring 32 are fixedly connected to the upper slider connector 35 and the middle slider connector 31 respectively; the rectangular spring 32 is sleeved outside the guide rail 34, and the guide rail 34 is placed at the center line of the rectangular spring 32. The upper slider connector 35, the middle slider connector 31, and the bottom of the lower slider connector 30 are respectively connected to the corresponding sliders 29. The slider 29 is located on the guide rail 34, thereby realizing the linear motion of the upper slider connector 35, the middle slider connector 31, and the bottom of the lower slider connector 30 on the guide rail 34; The Raspberry Pi controller 6 is fixed to the fixing plate 4 by bolts, and is fixed on the same side as the large joint motor 5, located at the bottom; the Raspberry Pi controller 6 is respectively connected to the large joint motor 5 and the small joint motor 22, and is used to control the large joint motor 5 and the small joint motor 22. The input end of the Raspberry Pi controller 6 is connected to the output end of the IMU inertial measurement sensor 9, serving as the data transmission and processing end of the IMU inertial measurement sensor 9 and the strain gauge 45. By processing the data of the IMU inertial measurement sensor 9 and the strain gauge 45, the gait state of the powered lower limb prosthesis can be sensed.

[0006] In order to achieve customization according to individual differences of amputees and different purposes of use, the powered lower limb prosthesis of the present invention adopts standard prosthetic joints for connection, so as to facilitate customization and replacement.

[0007] When an amputee wears the prosthesis of the present invention and walks, the normal working process of the prosthesis is as follows: First, the powered lower limb prosthesis includes a knee-ankle power coupling joint and an ankle joint. The knee-ankle power coupling joint can not only realize the flexion and extension of the knee joint, but also realize the plantar flexion of the ankle joint. The dorsiflexion of the ankle joint is mainly caused by the body's gravity causing the foot plate at the ankle joint to bend upward to realize the dorsiflexion movement. Here, the large joint motor 5 in the knee-ankle power coupling joint rotates counterclockwise to realize the flexion of the knee joint, and rotates clockwise to realize the extension of the knee joint. At the same time, the small joint motor 22 in the knee-ankle power coupling joint rotates clockwise instantaneously to realize the plantar flexion of the ankle joint. When the small joint motor 22 rotates counterclockwise, the ankle joint will return to its initial position. The kinetic energy of its recovery mainly comes from the tension spring fixed to it, that is, the tension spring stretches during plantar flexion. The knee-ankle powered coupling joint allows for a full range of knee joint motion (0-120 degrees), with a maximum ankle plantar flexion angle of 30 degrees. The Raspberry Pi controller 6, as the control assembly, is responsible for controlling the large joint motor 5 and the small joint motor 22, and also serves as the data transmission and processing terminal for the IMU inertial measurement sensor 9 and strain gauge 45. Control of the large joint motor 5 and the small joint motor 22 by the Raspberry Pi controller 6 can be divided into two phases based on gait: the stance phase and the swing phase. The stance phase is when the carbon fiber footplate 10 of the powered lower limb prosthesis is in contact with the ground, while the swing phase is when the carbon fiber footplate 10 is not in contact with the ground. The Raspberry Pi controller 6 primarily uses data from the IMU inertial measurement sensor 9 and strain gauge 45 to determine gait, determining whether the carbon fiber footplate 10 is in contact with or off the ground. During the stance phase, two scenarios may occur depending on the walking scenario. One scenario involves high torque demand, in which the self-locking mechanism is in a self-locking state. This is commonly seen in walking up and down stairs and slopes. The other is a scenario with small torque demand, that is, the self-locking mechanism is in the open state. At this time, the small joint motor in the knee-ankle power coupling joint does not participate in the work, which is common in walking scenarios on flat ground.

[0008] It is designed for scenarios with small torque requirements, such as walking on flat ground and other common scenarios.

[0009] The rotation of the large joint motor 5 in the knee-ankle power coupling joint will drive the transmission shaft 20 to rotate in the same direction, and the transmission shaft 20 will drive the small synchronous belt pulley 21 to rotate in the same direction. Therefore, the rotation of the large joint motor 5 shaft will drive the small synchronous belt pulley 21 to rotate in the same direction. When the knee joint needs to flex, the large joint motor 5 shaft rotates counterclockwise, driving the small synchronous belt pulley 21 to rotate counterclockwise. Under the rotation of the large joint motor 5, the large synchronous belt pulley 15 connected to the small pulley 21 through the synchronous belt 17 will rotate in the same direction. The large synchronous belt pulley 15 is fixedly connected to the fixed plate 4. Therefore, the counterclockwise rotation of the large joint motor 5 shaft will eventually drive the fixed plate 4 to rotate around the axis of the large synchronous belt pulley 15. Flexion of the knee joint is achieved. Similarly, when the large joint motor 5 shaft rotates clockwise, extension of the knee joint can be achieved. As for the plantar flexion of the ankle joint, the facet joint motor 22 is also fixed on the fixed plate 4, and the rotating shaft of the facet joint motor 22 can rotate around the fixed plate 4. And the coil disk 47 is fixedly connected to the rotating shaft of the facet joint motor 22. The cylindrical surface of the coil disk 47 has three groups of corresponding spherical grooves, wherein the upper end of the ankle joint drive rope 13 is wound around the spherical groove on the side of the coil disk 47 close to the facet joint motor 22 and fixedly connected thereto. The other side of the ankle joint drive rope 13 is wound around the spherical groove on the ankle joint pulley 12 and fixedly connected thereto. Therefore, the clockwise rotation of the facet joint motor will drive the ankle joint pulley 12 to rotate clockwise. The ankle joint pulley 12 is fixedly connected to the lower 44 of the ankle joint upper connector by bolts. The lower 44 sides of the ankle joint upper connector have protruding circular shafts, which are respectively equipped with bearings and cooperate with the inner holes of the right 8 and left 43 of the ankle joint upper connector to realize the rotation of the bearing hole axis of the lower 44 of the ankle joint upper connector around the right 8 and left 43 of the ankle joint upper connector. The bottom of the lower 44 of the ankle joint upper connector is fixedly connected to the foot plate connector 11 by bolts, and the bottom of the foot plate connector 11 is fixedly connected to the carbon fiber foot plate 10 by bolts. Therefore, the clockwise rotation of the ankle joint wire pulley 12 will eventually drive the rotation of the carbon fiber foot plate 10, realizing the plantar flexion of the ankle joint. One side of the ankle joint wire pulley 12 has a tension spring 46 fixed shaft, and the other end of the tension spring 46 is fixed on the right 8 of the ankle joint upper connector. Therefore, during the plantar flexion of the ankle joint, the tension spring 46 will be stretched. Therefore, when the facet joint motor 22 rotates counterclockwise, the ankle joint wire pulley 12 will be rotated counterclockwise in the process of being restored to the initial length by the tension spring 46, realizing the resetting of the ankle joint. It should be noted that the ankle joint pulley 12 can only rotate to 0 degrees, meaning it cannot achieve ankle dorsiflexion. The active working angle of the ankle joint is (0-30 degrees). However, due to the elasticity of the carbon fiber footplate 10, ankle dorsiflexion is primarily achieved through deformation of the carbon fiber footplate 10.

[0010] When the large joint motor 5 and the small joint motor 22 operate independently, their power is not coupled. However, for scenarios with high torque requirements, such as those common when going up and down stairs, when the knee joint needs to flex, the large joint motor 5's shaft rotates counterclockwise, driving the large synchronous pulley 15 to rotate in the same direction. The upper end of the spring-loaded drive rope 16 is wrapped around one side of the large synchronous pulley 15 and fixed to it. The lower end of the spring-loaded drive rope 16 is first wrapped around the large rocker 19 on the locking mechanism and then vertically downwardly connected to the lower slider connector 30 through a pulley. If the self-locking mechanism 37 is in the extended state, the large rocker 19 on the locking mechanism will swing counterclockwise when the large synchronous pulley 15 rotates counterclockwise. However, since the self-locking mechanism 37 is in the extended state, its special-shaped rocker 40 will prevent the large rocker 19 on the locking mechanism from swinging counterclockwise. Then, the lower slider connector 30 will translate upward under the pull of the spring-loaded drive rope 16. When the lower slider connector 30 moves to a position where it contacts the middle slider connector 31, it drives the middle slider connector 31 to move upward, squeezing the rectangular spring 32. It should be noted that when the lower slider connector 30 moves to the contact position set with the middle slider connector 31, the knee joint moves to approximately 20 degrees of flexion. When the lower slider connector 30 moves to the contact position set with the middle slider connector 31, the rotation of the large synchronous pulley 15 compresses the rectangular spring 32, forming a parallel spring actuator mechanism. Energy is stored by compressing the spring. When it is detected that the stair surface is stepped on, the flexion is converted into an extension movement, and the spring energy is released, increasing the knee joint torque. At the same time, if the spring energy storage plus the power of the large joint motor 5 still cannot meet the required joint torque, the small joint motor 22 will intervene. Specifically, the rotating shaft of the small joint motor 22 rotates counterclockwise, driving the coil disk 47 to rotate in the same direction. The coil disk 47 has three parallel spherical coil slots, which are respectively connected to the ankle joint drive rope 13, the spring pressure drive rope 33, and the locking mechanism drive rope 27. Counterclockwise rotation of the coil disk 47 causes the upper slider connector 35, to which the other end of the spring pressure drive rope 33 is attached, to slide downward, pressing down the rectangular spring 32, and thus pressing down the lower slider connector 30, which contacts the middle slider connector 31. This in turn helps the large synchronous pulley 15 rotate clockwise, achieving joint extension. This in turn allows the small joint motor 22 to assist the large joint motor 5.

[0011] At the same time, for the above two situations, the movement of the ankle joint is performed by the small joint motor 22. The switching between the high torque demand scenario and the low torque demand scenario is also performed by the small joint motor 22. It is mainly completed by the locking mechanism drive rope 27 fixedly connected to the coil disk 47. Specifically, when the rotating shaft of the small joint motor 22 rotates clockwise, it drives the coil disk 47 to rotate in the same direction. The locking mechanism drive rope 27 will drive the large rocker 19 on the locking mechanism to swing clockwise around the axis, and the short shaft fixed to the large rocker 19 on the locking mechanism will drive the special-shaped rocker 39 to rotate counterclockwise. Similarly, the special-shaped rocker lower 40 fixed to the special-shaped rocker upper 39 rotates in the same direction. The small rocker 18 on the locking mechanism, connected to the upper shaped rocker 39 via a revolute joint, swings under its influence. Simultaneously, the other end of the small rocker 18 is connected to the right-angle connecting rod 38, also via a revolute joint. The other end of the right-angle connecting rod 38 is fixedly connected to the telescopic rod of the push-and-lock mechanism 37. When the large rocker 19 on the locking mechanism swings clockwise about its axis, it compresses the telescopic rod of the push-and-lock mechanism 37 until the push-and-lock mechanism 37 locks the telescopic rod. Then, when the large rocker 19 on the locking mechanism swings counterclockwise, it is no longer blocked by the lower shaped rocker 40, thereby releasing the large rocker 19 on the locking mechanism.

[0012] The beneficial effects of the present invention are: (1) The thigh prosthesis of the present invention innovatively couples the power of the knee joint motor with the ankle joint motor, thereby reducing the power requirements of each individual joint motor. The knee joint motor and the ankle joint motor can simultaneously provide power for flexion and extension of the knee joint. Therefore, amputees wearing the thigh prosthesis of the present invention can achieve normal walking for long periods of time or complete basic daily movements such as climbing and descending stairs and squatting and standing up.

[0013] (2) The thigh prosthesis is driven by dual motors, which can actively achieve knee flexion and extension, as well as ankle plantar flexion. The knee joint uses a synchronous belt drive, which has the advantages of compact structure, good back-drive performance, and low drive noise. The ankle joint adopts an active-passive hybrid, and its dorsiflexion is mainly achieved by the body's weight acting on the foot, which effectively reduces energy consumption and joint size.

[0014] (3) The thigh lower limb prosthesis is designed with a knee-ankle power coupling transmission mechanism, which is completed by a parallel spring mechanism and a press-locking mechanism. The force coupling relationship between the knee joint motor and the ankle joint motor is adjusted according to different torque requirements. It can effectively adapt to different walking styles in daily life. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is an overall view of the knee-ankle powered coupled thigh lower limb prosthesis of the present invention.

[0016] Figure 2 This is a view of the knee-ankle dynamic coupling joint of the present invention.

[0017] Figure 3 2 is a view of the parallel spring mechanism of the present invention.

[0018] Figure 4 1. The self-locking mechanism of the present invention is shown in FIG. 1. (A) is an axonometric view of the self-locking mechanism, and (B) is a front view of the self-locking mechanism.

[0019] Figure 5 The present invention is an ankle joint view, wherein: (A) is an ankle joint axonometric view, and (B) is an ankle joint assembly view.

[0020] Figure 6 2 is a view of a rope drive system according to the present invention.

[0021] Markings in the figure: 1. Socket connector, 2. Standard connector on the knee joint, 3. Right upper connector on the knee joint, 4. Fixation plate, 5. Large joint motor, 6. Raspberry Pi controller, 7. Knee-ankle joint connector, 8. Right upper connector on the ankle joint, 9. IMU inertial measurement sensor, 10. Carbon fiber footplate, 11. Footplate connector, 12. Ankle joint pulley, 13. Ankle joint drive rope, 14. Left upper connector on the knee joint, 15. Large synchronous pulley, 16. Spring-loaded drive rope, 17. Synchronous belt, 18. Small rocker on the locking mechanism, 19. Large rocker on the locking mechanism, 20. Drive shaft, 21. Small synchronous pulley, 22. Small joint motor, 23. Ankle joint drive rope tensioning pulley, 24. Torsion spring, 25. Locking mechanism drive rope tensioning pulley, 26. Locking mechanism drive rope lower pulley, 27. Locking mechanism drive rope, 28. Spring-loaded drive rope tensioning pulley, 29. Slider, 30. Slider connector, lower part, 31. Slider connector, middle part, 32. Rectangular spring, 33. Spring-loaded drive rope, 34. Guide rail, 35. Slider connector, upper part, 36. Locking mechanism drive rope upper pulley, 37. Press-on self-locking mechanism, 38. Right-angle connecting rod, 39. Special-shaped rocker, upper part, 40. Special-shaped rocker, lower part, 41. Short shaft, 42. Standard joint on ankle joint, 43. Left connector on ankle joint, 44. Lower connector on ankle joint, 45. Strain gauge, 46. Tension spring, 47. Coil disk. DETAILED DESCRIPTION

[0022] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0023] Example 1: Reference Figure 1A powered lower limb prosthesis is provided, characterized by comprising: a joint connector, a knee-ankle power coupling joint, an ankle joint, a parallel spring mechanism, a self-locking mechanism, a drive rope pretensioning mechanism, and a rope drive system. The joint connector comprises a socket connector 1, a standard upper knee joint connector 2, a right upper knee joint connector 3, and a knee-ankle joint connector 7. The knee-ankle power coupling joint comprises a large joint motor 5, a small joint motor 22, a synchronous belt 17, a large synchronous pulley 15, and a small synchronous pulley 21. The ankle joint comprises a standard upper ankle joint connector 42, a left upper ankle joint connector 43, a right upper ankle joint connector 8, a lower ankle joint connector 44, a strain gauge 45, a tension spring 46, an IMU inertial measurement sensor 9, and a carbon fiber footplate 10. The self-locking mechanism primarily comprises a press-type self-locking mechanism 37, a right-angle connecting rod 38, an upper special-shaped rocker 39, a lower special-shaped rocker 40, and a short shaft 41. The parallel spring mechanism primarily includes a slider 29, a lower slider connector 30, a middle slider connector 31, a rectangular spring 32, a guide rail 34, and an upper slider connector 35. The drive rope pretensioning mechanism primarily includes the ankle joint drive rope tensioning pulley 23, a locking mechanism drive rope tensioning pulley 25, a locking mechanism drive rope lower pulley 26, a spring-loaded drive rope tensioning pulley 28, and a locking mechanism drive rope upper pulley 36. The rope drive system primarily includes the ankle joint pulley 12, the ankle joint drive rope 13, a spring-loaded drive rope 16, a locking mechanism drive rope 27, and a spring-loaded drive rope 33. The Raspberry Pi controller 6 is bolted to the fixed plate 4 and fixed to the same side as the large joint motor 5, located below. As the control assembly, the Raspberry Pi controller 6 is responsible for controlling the large joint motor 5 and the small joint motor 22, and also serves as the data transmission and processing terminal for the IMU inertial measurement sensor 9 and the strain gauge 45. The Raspberry Pi controller 6 controls the large joint motors 5 and small joint motors 22 in two phases based on gait: the stance phase and the swing phase. The stance phase is when the carbon fiber footplate 10 of the powered lower limb prosthesis is in contact with the ground, while the swing phase is when the carbon fiber footplate 10 is not in contact with the ground. The Raspberry Pi controller 6 primarily uses data from the IMU inertial measurement sensor 9 and strain gauge 45 to determine whether the carbon fiber footplate 10 is in contact with or off the ground.

[0024] refer to Figure 2Knee joint view, the receiving cavity connector 1 is provided with a cylindrical hole inside, so that the standard connector 2 on the knee joint can cooperate with it and be fixed by bolts. The standard connector 2 on the knee joint is provided with a threaded hole on each side, and the right upper connector 3 of the knee joint and the left upper connector 14 of the knee joint are respectively fixed on both sides by bolts. At the same time, the inner side of the right upper connector 3 of the knee joint and the left upper connector 14 of the knee joint are each provided with a bearing mounting boss, and the axis centers are collinear. The fixing plate 4 is provided with a bearing mounting hole inside, so that the fixing plate 4 can be installed between the right upper connector 3 of the knee joint and the left upper connector 14 of the knee joint, fixed by bearings, and forming a revolving pair, so that the fixing plate 4 can rotate around the axis centers of the right upper connector 3 of the knee joint and the left upper connector 14 of the knee joint, thereby realizing flexion and extension of the knee joint. At the same time, the large joint motor 5 is fixed to the fixing plate by bolts, and the base of the transmission shaft 20 is provided with a threaded hole, which corresponds to the threaded hole on the surface of the large joint motor 5 and is fixed by bolts. At the same time, the cross-sectional shape of the end of the drive shaft 20 facing away from the large joint motor 5 is deformed to a hexagonal shape, while the center hole of the small synchronous pulley 21 also has a hexagonal cross-sectional shape with identical parameters. The small synchronous pulley 21 is mounted on the drive shaft 20 to achieve synchronous rotation. Meanwhile, the large synchronous pulley 15 is fixed to the fixed plate 4 via a bearing, and the end faces of the large synchronous pulley 15 and the small synchronous pulley 21 are aligned. The axis of the large synchronous pulley 15 is collinear with the axes of the right and left upper knee joint connectors 3 and 14, and the large synchronous pulley 15 is fixedly connected to the right and left upper knee joint connectors 14, respectively. The large synchronous pulley 15 and the small synchronous pulley 21 are connected by a synchronous belt 17. Therefore, when the shaft of the large joint motor 5 rotates, it drives the large synchronous pulley 15 to rotate in the same direction, thereby driving the fixed plate 4 to rotate around the axes of the right and left upper knee joint connectors 3 and 14, thereby achieving flexion and extension of the knee joint.

[0025] refer to Figure 2 and Figure 3 The upper end of the spring-loaded driving rope 16 is wound around one side of the large synchronous pulley 15, and the end is fixed to it. The lower section of the spring-loaded driving rope 16 passes through the middle hole of the rectangular spring 32 and is fixed to the lower slider connector 30. The middle part of the spring-loaded driving rope 16 is wound around the pulleys at both ends of the large rocker 19 on the locking mechanism. A pulley is fixed at both ends of the upper side of the large rocker 19 on the locking mechanism, and a bearing mounting hole is provided at the bottom of the other side. The bearing mounting hole cooperates with the bearing on the fixed plate 4 to realize the swinging motion of the large rocker 19 on the locking mechanism around the axis set by the fixed plate 4. Figure 6The facet joint motor 22 housing is bolted to the fixing plate, and the coil disk 47 is fixed to the rotating shaft of the facet joint motor 22, enabling the coil disk 47 and the rotating shaft of the facet joint motor 22 to rotate in the same direction. Three spherical grooves are arranged along the axis of the coil disk 47, respectively securing the upper end of the ankle joint drive rope 13, the lower end of the locking mechanism drive rope 27, and the lower end of the spring-loaded drive rope. The upper end of the spring-loaded drive rope is fixed to the slider connector 35. The upper end of the locking mechanism drive rope 27 is fixed to the spherical groove at the bottom of the locking mechanism's large rocker 19. The bottom spherical groove and its axis are collinear with the rotation axis of the locking mechanism's large rocker 19.

[0026] refer to Figure 3 In a parallel spring mechanism, the ends of a rectangular spring 32 are secured by the upper and middle slider connectors 35 and 31, respectively. A guide rail 34 is positioned parallel to the centerline of the rectangular spring 32 and positioned between the springs. The upper, middle, and lower slider connectors 35, 31, and 30 all have center holes to prevent collisions with the guide rails 34 during movement. The bottoms of the upper, middle, and lower slider connectors 35, 31, and 30 are all securely connected to the slider 29, enabling linear motion on the guide rails 34.

[0027] refer to Figure 4 The self-locking mechanism features a through-hole perpendicular to the horizontal plane on the end of the large rocker 19 on the locking mechanism, away from the rotation axis. A short shaft 41 is installed in this hole and securely connected to it. The short shaft protrudes no higher than the height of the shaped rocker 39 on the upper part. This means that when the shaped rocker 39 rotates about its rotation axis, it comes into contact with the short shaft 41. The bottom of the shaped rocker 39 is fixed to the shaped rocker 40 on the same rotation axis. During rotation, the shaped rocker 40 will come into contact with the protruding cylinder in the center of the large rocker 19 on the locking mechanism within a specified angle range. Furthermore, the side of the shaped rocker 39 away from the short shaft 41 is equipped with a rotation axis, which forms a revolute pair with the small rocker 18 on the locking mechanism, allowing it to rotate about its rotation axis. The other side of the small rocker 18 on the locking mechanism forms a revolute pair with the right-angle connecting rod 38, which is also securely connected to the telescopic rod that presses the self-locking mechanism 37.

[0028] refer to Figure 5Ankle joint assembly diagram, strain gauges 45 are attached to the top front side of the carbon fiber foot plate 10 and the bottom of the arch to detect whether the prosthetic foot plate is in contact with or separated from the ground. At the same time, the IMU inertial measurement sensor 9 is fixedly connected to the front end of the foot plate connector 11, which is also used to detect whether the prosthetic foot plate is in contact with or separated from the ground. The carbon fiber foot plate 10 is connected to the lower ankle joint connector 44 through the foot plate connector 11, and both are connected by bolts. Horizontal protruding shaft end faces are provided on both sides of the lower ankle joint connector 44, which can be installed with bearings and are respectively connected to the right ankle joint connector 8 and the left ankle joint connector 43, thereby forming a revolute pair. At the same time, a rectangular space is provided in the middle of the lower ankle joint connector 44, and the ankle joint pulley 12 is placed in the middle and fixed by bolts. In addition, threaded holes are provided on the top of the right ankle joint connector 8 and the left ankle joint connector 43, which are fixed to the standard joint on the ankle joint by bolts. As a result, the ankle pulley 12 rotates around the center hole axis of the right ankle connector 8 and the left ankle connector 43 under the drive of the ankle drive rope 13, and then drives the carbon fiber foot plate 10 to rotate around the center hole axis of the right ankle connector 8 and the left ankle connector 43.

[0029] refer to Figure 6 View of the rope drive system. The upper end of the locking mechanism drive rope 27 is wrapped around the spherical groove of the locking mechanism upper large rocker 19 and is fixedly connected to the locking mechanism upper large rocker 19. The locking mechanism drive rope 27 passes between the locking mechanism drive rope upper pulley 36 and the locking mechanism upper large rocker 19, wraps around the locking mechanism drive rope upper pulley 36, and extends downward. The locking mechanism drive rope 27 extends vertically downward to the locking mechanism drive rope lower pulley 26 and wraps around it. It then passes through the locking mechanism drive rope tensioning pulley 25 and wraps around the spherical groove of the coil disk 47. The coil disk 47 is provided with three equally spaced spherical grooves, each for securing a corresponding drive rope. The lower end of the locking mechanism drive rope 27 is fixedly connected to the coil disk 47, and the lower portion of the locking mechanism drive rope 27 is wrapped around the spherical groove farthest from the facet joint motor 22. The lower portion of the spring-loaded drive rope 33 is wound around the central spherical groove on the coil disk 47, and the lower end of the spring-loaded drive rope 33 is fixedly connected to the coil disk 47. The lower portion of the spring-loaded drive rope 33 passes along the bottom spherical groove on the spring-loaded drive rope tensioning pulley 28, passes through the slider connector 31 and the rectangular spring 32, and finally, its upper end is fixedly connected to the slider connector 35. The right side of the slider connector 31 is provided with a through hole, through which the spring-loaded drive rope 33 can pass without contacting it. The upper portion of the ankle joint drive rope 13 is wound around the spherical groove on the coil disk 47 closest to the facet joint motor 22, and the upper end of the ankle joint drive rope 13 is fixedly connected to the coil disk 47.

Claims

1. A knee-ankle powered coupled thigh lower limb prosthesis comprising a joint connector, a knee-ankle powered coupled joint, an ankle joint, a self-locking mechanism, a parallel spring mechanism, a Raspberry Pi controller (6), an IMU inertial measurement sensor (9), a drive rope pre-tightening mechanism, and a rope drive system, characterized in that: The rope drive system comprises an ankle joint pulley (12), an ankle joint driving rope (13), a spring-pressing driving rope (16), a locking mechanism driving rope (27), a spring-pressing driving rope (33) and a coil disk (47); the ankle joint pulley (12) is sleeved on the ankle joint driving rope (13); the coil disk (47) is provided with three spherical coil grooves arranged side by side, which are respectively connected to the ankle joint driving rope (13), the locking mechanism driving rope (27) and the spring-pressing driving rope (33); The joint connector includes a receiving cavity connector (1), a standard upper knee joint connector (2), a right upper knee joint connector (3), a knee-ankle joint connector (7) and a left upper knee joint connector (14); the receiving cavity connector (1) is fixed to the upper portion of the standard upper knee joint connector (2) by bolts; the right upper knee joint connector (3) and the left upper knee joint connector (14) are respectively fixed to both sides of the standard upper knee joint connector (2) by bolts; the right upper knee joint connector (3) and the left upper knee joint connector (14) are both provided with bearing mounting bosses on their inner sides, and their axes are collinear; a fixing plate (4) is provided between the right upper knee joint connector (3) and the left upper knee joint connector (14); a bearing mounting hole is provided on the fixing plate (4); the right upper knee joint connector (3) and the left upper knee joint connector (14) are connected to the fixing plate (4) by bearings to form a rotation pair; The knee-ankle power coupling joint comprises a fixing plate (4), a transmission shaft (20), a large joint motor 5, a small joint motor (22), a synchronous belt (17), a large synchronous pulley (15) and a small synchronous pulley (21); the large synchronous pulley (15) is fixed to the fixing plate (4) through a bearing, and the base of the transmission shaft (20) is fixedly connected to the large joint motor (5) through a bolt; the cross-section of the end of the transmission shaft (20) away from the large joint motor (5) is hexagonal, and the center hole of the small synchronous pulley 21 passes through the hexagonal cross-section, so that the small synchronous pulley (21) and the transmission shaft (20) can rotate synchronously; the large synchronous pulley (15) is respectively connected to the upper and lower ends of the knee joint The right part (3) and the left part (14) of the knee joint upper connection are fixedly connected, and the axis of the large synchronous pulley (15) is collinear with the axis of the right part (3) and the left part (14) of the knee joint upper connection; the end faces of the large synchronous pulley (15) and the small synchronous pulley (21) are kept on the same plane, and the large synchronous pulley (15) and the small synchronous pulley (21) are connected by a synchronous belt (17); when the shaft of the large joint motor 5 rotates, the large synchronous pulley (15) can be driven to rotate in the same direction, thereby driving the fixed plate (4) to rotate around the axis of the right part (3) and the left part (14) of the knee joint upper connection to achieve flexion and extension of the knee joint; The ankle joint comprises an upper standard joint (42), an upper left ankle joint connector (43), an upper right ankle joint connector (8), a lower ankle joint connector (44), a strain gauge (45), a tension spring (46) and a carbon fiber foot plate (10). The carbon fiber foot plate (10) is provided with strain gauges (45) on the front top and the bottom of the arch of the foot. The strain gauge (45) is connected to an IMU inertial measurement sensor (9) to detect whether the carbon fiber foot plate (10) is in contact with or separated from the ground. The carbon fiber foot plate (10) is connected to the lower ankle joint connector (44) via a foot plate connector (11). Both sides of the lower ankle joint connector (44) are provided with horizontal protruding shaft end faces for mounting bearings. The lower ankle joint connector (44) is connected to the right ankle joint connector (8) and the left ankle joint connector (43) via bearings on both sides to form a revolute pair. A rectangular space is provided in the middle of the lower ankle joint connector (44), and the ankle joint pulley (12) is placed in the middle of the rectangle and fixedly connected by bolts; the tops of the right ankle joint connector (8) and the left ankle joint connector (43) are fixedly connected to the standard ankle joint connector (42) by bolts respectively; the ankle joint pulley (12) rotates around the axis of the center hole of the right ankle joint connector (8) and the left ankle joint connector (43) under the drive of the ankle joint driving rope (13), and then drives the carbon fiber foot plate (10) to rotate around the axis of the center hole of the right ankle joint connector (8) and the left ankle joint connector (43); one end of the tension spring (46) is connected to the fixed shaft on one side of the ankle joint pulley (12), and the other end is fixed to the right ankle joint connector (8). During the plantar flexion of the ankle joint, the tension spring (46) will be stretched; The self-locking mechanism comprises a large rocker (19) on the locking mechanism, a pressing self-locking mechanism (37), a right-angle connecting rod (38), an upper special-shaped rocker (39), a lower special-shaped rocker (40) and a short shaft (41); the upper large rocker (19) of the locking mechanism is provided with a through hole on a vertical horizontal plane at one end away from the rotation axis, and a short shaft (41) is installed in the through hole, and the protruding height of the short shaft (41) is not higher than the upper special-shaped rocker (39); that is, the upper special-shaped rocker (39) rotates around the rotation axis and contacts the short shaft (41); the bottom of the upper special-shaped rocker (39) and the lower special-shaped rocker (40) are connected by rotation. The rotating shaft is fixedly connected, and the lower part of the special-shaped rocker (40) contacts the middle protruding cylinder of the large rocker (19) on the locking mechanism within a specified angle range during rotation; the upper part of the special-shaped rocker (39) is provided with a rotating shaft on the side away from the short axis (41), and the upper part of the special-shaped rocker (39) can form a rotating pair with the small rocker (18) on the locking mechanism, so that the small rocker (18) on the locking mechanism rotates around its rotating axis; the other side of the small rocker (18) on the locking mechanism forms a rotating pair with the right-angle connecting rod (38), and the right-angle connecting rod (38) is fixedly connected to the telescopic rod of the pressing self-locking mechanism (37); The parallel spring mechanism includes a slider (29), a slider connector lower (30), a slider connector middle (31), a rectangular spring (32), a guide rail (34) and a slider connector upper (35), and there are three sliders (29); the two ends of the rectangular spring (32) are fixedly connected to the slider connector upper (35) and the slider connector middle (31); the rectangular spring (32) is sleeved outside the guide rail (34), and the guide rail (34) is placed at the center line of the rectangular spring (32), and the slider connector upper (35), the slider connector middle (31), and the slider connector lower (30) are connected to the corresponding sliders (29) respectively. The slider (29) is located on the guide rail (34), thereby realizing the linear motion of the slider connector upper (35), the slider connector middle (31), and the slider connector lower (30) on the guide rail (34); The Raspberry Pi controller (6) is fixed to the fixing plate (4) by bolts and is fixed on the same side as the large joint motor 5 and is located at the bottom. The Raspberry Pi controller (6) is connected to the large joint motor (5) and the small joint motor (22) respectively, and is used to control the large joint motor 5 and the small joint motor (22). The input end of the Raspberry Pi controller (6) is connected to the output end of the IMU inertial measurement sensor (9), serving as a data transmission and processing end for the IMU inertial measurement sensor (9) and the strain gauge (45). By processing the data of the IMU inertial measurement sensor (9) and the strain gauge (45), the gait state of the powered lower limb prosthesis is sensed.

2. The knee-ankle powered coupled thigh lower limb prosthesis according to claim 1, characterized in that Powered lower limb prostheses are connected using standard prosthetic joints and are customized based on individual differences and intended uses of amputees for easy replacement.

Images