Lower extremity auxiliary drive mechanism and robot

Abstract

The application discloses a lower limb auxiliary driving mechanism and a robot, which comprises a thigh assembly and a lower leg assembly connected with the thigh assembly, and a connecting end of a thigh connecting piece two and the lower leg assembly forms a knee joint. In the application, a constant force load mechanism is arranged on the thigh assembly, constant tension of a spring is converted into a compensation torque acting on the knee joint, so that the compensation torque can directly offset part or all of the bending moment generated by the weight of the lower limb on the knee joint, thereby realizing accurate compensation of the static load of the knee joint, reducing the driving burden when the joint maintains a posture, and the constant force load spring serves as a parallel auxiliary execution mechanism and jointly bears the load of the knee joint with a motor driving system. Through the parallel sharing mode, the joint load originally borne by the motor can be reasonably distributed, the motor works in a relatively stable and high-efficiency interval more, peak load is reduced, current impact is reduced, and overall driving efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of robotics, and more specifically to a lower limb assistive drive mechanism and robot. Background Technology

[0002] Existing lower limb assist or knee joint assist devices often employ pure motor direct drive, reducer drive, or single elastic element assistance to achieve joint assistance. These solutions generally suffer from the following shortcomings:

[0003] Firstly, the knee joint needs to continuously overcome the weight of the lower limbs and the inertia of movement when standing, walking and lifting the leg. Pure motor drive mode is prone to making the motor work in the high load range for a long time, resulting in high energy consumption, large heat generation and low response efficiency. Secondly, existing spring-assisted solutions often have unstable output characteristics, making it difficult to provide approximately constant assistance over a long stroke, resulting in significant variations in the assistance effect with the joint angle. Third, joints are prone to impact loads when starting, stopping, unloading or changing posture. Existing structures lack effective buffer and damping designs, which can easily cause vibration, unstable control and component fatigue. Fourth, some solutions are large in size and have limited layout space, making them unsuitable for integration in compact spaces such as thighs.

[0004] In existing technologies, the knee joint in lower limb assistive devices, rehabilitation exoskeletons, and humanoid robot leg mechanisms typically bears a large bending moment load during human or mechanism movement. To reduce the burden on the drive unit, common solutions in existing technologies include: 1. Pure motor drive scheme: The knee joint is directly driven to complete flexion and extension through a motor, reducer, and linkage. This scheme is easy to control, but all the load is mainly borne by the motor, with a large peak torque, which can easily lead to increased motor size, increased energy consumption, and system overheating. 2. Conventional Spring-Assisted Solution: This solution uses tension springs, torsion springs, or other elastic elements on both sides of the joint to assist joint extension by storing elastic energy. While structurally simple, the elastic force output typically varies significantly with the stroke, making it difficult to provide constant assistance over long strokes. Furthermore, the springs are significantly limited by installation space. This solution also suffers from an uneven assistance curve, inaccurate load compensation, and insufficient shock absorption. Moreover, it struggles to maintain a nearly constant extension trend during long-stroke knee movements, requiring the motor to frequently participate in peak compensation, resulting in low overall system efficiency. These drawbacks are even more pronounced in scenarios requiring user-friendly interaction, smooth movement, and a compact wearing space. 3. Rope-driven or pulley-driven force transmission scheme: The power or elastic force at the remote end is transmitted to the joint through steel wire rope, synchronous belt or flexible transmission component. The advantage is that the arrangement is flexible and the force transmission over long distance is convenient. However, if it is only used as a force transmission mechanism, it is still difficult to simultaneously take into account constant force output, buffering and vibration reduction and energy recovery. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to provide a lower limb auxiliary drive mechanism that can achieve continuous and stable straightening assistance and gravity compensation, reduce motor load, and buffer transient impacts in a relatively compact space.

[0006] This invention solves the above-mentioned technical problems through the following technical means: a lower limb auxiliary drive mechanism, including a thigh assembly and a lower leg assembly connected to the thigh assembly, wherein the connection end of the thigh connector and the lower leg assembly forms a knee joint, characterized in that the thigh assembly includes a thigh connector one and a thigh connector two elastically connected by a spring, the thigh connector two is provided with a constant force load mechanism, the constant force load mechanism includes a transmission wheel one and a transmission wheel two, a knee joint drive motor is fixedly connected to the end of the thigh connector two, the output end of the knee joint drive motor is fixedly connected to the lower leg assembly and can drive the lower leg assembly to rotate, the thigh connector two is rotatably connected with the transmission wheel one, the transmission wheel one is provided with a constant force load spring, the coiled spring is transmitted to the transmission wheel two fixed to the lower leg assembly through a load rope; the constant force load mechanism can share part of the torque and can counteract the bending moment generated by the weight of the lower limb on the knee joint.

[0007] As a preferred technical solution, one end of the load rope is fixedly connected to the constant force load spring, and the other end is wound and fixed to the transmission wheel.

[0008] As a preferred technical solution, it also includes an ankle joint and a foot. The end of the lower leg assembly away from the thigh assembly is movably connected to the foot through a differential bracket of the ankle joint. The lower leg assembly includes the lower leg and two ankle motors fixed on the lower leg. The output ends of the two ankle motors are each driven by a drive wheel. The two opposite ends of the differential bracket are rotatably connected to a driven wheel. The diameter of the driven wheel is larger than that of the drive wheel. The other opposite ends are rotatably connected to a differential wheel. The two drive wheels are each driven by a drive rope and a driven wheel. The two driven wheels are driven by a differential rope and the two differential wheels. Driving the two drive wheels to rotate in opposite directions can drive the foot to roll relative to the lower leg assembly. Driving the two drive wheels to rotate in the same direction can drive the foot to pitch relative to the lower leg assembly.

[0009] As a preferred technical solution, the differential support is circumferentially fixed with a front axle, a rear axle, a left axle, and a right axle arranged in a cross shape. A passive wheel is fixedly connected to the left axle and the right axle, and a differential wheel is fixedly connected to the front axle and the rear axle, respectively. The ankle joint includes a joint frame one and a joint frame two. One end of the joint frame is fixedly connected to the lower leg assembly, and the other end is rotatably connected to the left axle and the right axle. One end of the joint frame two is fixedly connected to the foot, and the other end is rotatably connected to the front axle and the rear axle.

[0010] As a preferred technical solution, the passive wheel includes wheel three and wheel four, the differential wheel includes wheel five and wheel six, and the differential rope includes rope three, rope four, rope five and rope six. Wheel three is connected to wheel six through rope three, wheel six is ​​connected to wheel four through rope four, wheel three is connected to wheel five through rope five, and wheel four is connected to wheel five through rope six.

[0011] As a preferred technical solution, the driving wheel includes wheel one and wheel two, and the transmission rope includes rope one and rope two. Wheel one is connected to wheel three through rope one, and wheel two is connected to wheel four through rope two.

[0012] As a preferred technical solution, the connecting surfaces of leg connector 1 and thigh connector 2, as well as the connecting surfaces of thigh connector 2 and thigh connector 1, are provided with evenly arranged mating holes. Springs are placed in the mating holes, and thigh connector 1 is elastically connected to thigh connector 2 through the springs.

[0013] As a preferred technical solution, the inner fixed connection of the thigh connector is a limiting nut, and the thigh connector is slidably connected with a bolt, which is threadedly connected to the limiting nut.

[0014] As a preferred technical solution, the first thigh connector has holes 1, 2, and 3 sequentially opened along the axial direction of the mating hole, and the second thigh connector has holes 4, 5, and 6 sequentially opened along the axial direction of the mating hole. Hole 1 is adapted to the size of the large end of the bolt, holes 2 and 6 are adapted to the size of the small end of the bolt, holes 3 and 4 are adapted to the size of the spring, and hole 5 is adapted to the size of the nut.

[0015] The present invention also provides a robot, including a lower limb assistive drive mechanism.

[0016] The beneficial effects of this invention are as follows: (1) In this invention, by setting a constant force load mechanism on the thigh assembly, the constant tension output by the spring is converted into a compensating torque acting on the knee joint, which can directly offset part or all of the bending moment generated by the weight of the lower limb on the knee joint, thereby achieving precise compensation for the static load of the knee joint and reducing the driving burden when the joint maintains its posture. At the same time, the CFS constant force load spring, as a parallel auxiliary actuator, shares the load of the knee joint with the motor drive system. Through this parallel sharing method, the joint load that was originally concentrated on the motor can be reasonably distributed, so that the motor can work more in a relatively stable and efficient range, reducing peak load, reducing current surge, and improving overall drive efficiency.

[0017] (2) In this invention, since the rope has a certain elasticity and the pulley system has a flexible connection feature, it can output high torque while also having a certain passive compliance. When the foot collides with the ground or external objects, the micro-stretching of the rope and the elastic response of the pulley system can absorb some of the impact energy, avoid the "hard-on-hard" problem caused by rigid mechanisms, and improve the safety and durability of the system. In the robot's gait cycle, the ankle joint will exchange energy during the support and swing phases. Through the flexible energy storage characteristics of the rope system, some elastic potential energy can be temporarily stored during the joint movement and released in subsequent actions, thus having a certain potential for energy recovery and efficient storage. At the same time, since the main motor and transmission components can be arranged on the lower leg or closer to the body, the foot structure can be extremely lightweight, significantly reducing the swing leg inertia and improving gait efficiency and movement flexibility.

[0018] (3) In this invention, by setting passive wheels and active wheels with different wheel diameter ratios, a larger driving torque can be generated through a smaller output motor and rope wheel, thereby meeting the high torque requirements of the robot when walking, lifting, and adjusting its posture, while also meeting the compactness requirements. The differential rope forms a closed or semi-closed force transmission path under the action of the passive wheel and the differential wheel. When the ankle motor performs differential control on different ropes, it can make the ankle joint rotate in the corresponding direction, realizing posture correction, balance control, and foot compliance adjustment. Through the coordinated drive and the combination of different wheel diameter ratios of the passive wheel and the active wheel, not only is the output torque improved, but also the accuracy of posture control and dynamic response capability are improved. By dividing the thigh into two elastically connected parts, the impact force of the entire lower limb mechanism on the torso can be reduced. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the lower limb drive mechanism provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the lower leg assembly structure provided in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the thigh component structure provided in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the exploded structure of the thigh assembly provided in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the cross-sectional structure of the thigh assembly provided in Embodiment 1 of the present invention; Figure 6 This is a top view schematic diagram of the passive wheel and differential wheel cooperation structure provided in Embodiment 1 of the present invention; Figure 7 This is a bottom view of the structure of the passive wheel and differential wheel in embodiment 1 of the present invention; Figure 8This is a schematic diagram of the thigh component structure provided in Embodiment 2 of the present invention; Figure 9 This is a schematic diagram of the load rope routing structure provided in Embodiment 2 of the present invention; Figure 10 This is a schematic diagram of the constant force load mechanism provided in Embodiment 2 of the present invention; Reference numerals: 1. Thigh assembly; 11. Thigh connector one; 111. Hole one; 112. Hole two; 113. Hole three; 12. Thigh connector two; 121. Hole four; 122. Hole five; 123. Hole six; 124. Constant force load spring; 125. Transmission wheel one; 126. Load rope; 127. Transmission wheel two; 128. Knee joint drive motor; 13. Spring; 14. Bolt; 15. Limit nut; 2. Lower leg assembly; 20. Lower leg; 21. Ankle motor; 22. Drive wheel; 221. Wheel 1; 222. Wheel 2; 23. Drive rope; 231. Rope 1; 232. Rope 2; 24. Driven wheel; 241. Wheel 3; 242. Wheel 4; 25. Differential wheel; 251. Wheel 5; 252. Wheel 6; 26. Differential rope; 261. Rope 3; 262. Rope 4; 263. Rope 5; 264. Rope 6; 3. Ankle joint; 31. Joint frame 1; 32. Joint frame 2; 33. Differential support; 4. Foot. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1 See Figure 1 The lower limb auxiliary drive mechanism includes a thigh component 1, a calf component 2, an ankle joint 3, and a foot 4. One end of the calf component 2, i.e. the end of the calf component 2 facing the thigh component 1, is rotatably connected to the thigh component 1. The other end of the calf component 2, i.e. the end of the calf component 2 away from the thigh component 1, is rotatably connected to the foot 4 through the ankle joint 3.

[0022] The thigh assembly 1 includes a thigh connector 11 and a thigh connector 2 12. The thigh connector 11 and the thigh connector 2 12 are elastically connected to each other, thereby reducing the impact force of the entire lower limb mechanism on the torso. In this embodiment, one end of the spring 13 is connected to the thigh connector 11 and the other end of the spring 13 is connected to the thigh connector 2 12. See Figure 3 , Figure 4In order to adjust the extension and retraction of spring 13, evenly arranged mating holes are provided on the connecting surfaces of thigh connector 11 and thigh connector 2 12, as well as on the connecting surfaces of thigh connector 2 12 and thigh connector 11. A limiting post is provided between thigh connector 11 and thigh connector 2 12. The limiting post includes a bolt 14 and a limiting nut 15 (not shown in the figure). The small end of the bolt 14 passes through the mating hole of thigh connector 11 and the mating hole of thigh connector 2 12. The end face of the bolt 14 passing through the mating hole on thigh connector 2 12 is threadedly connected to the limiting nut 15. The limiting nut 15 is threadedly connected to the bolt 14.

[0023] See Figure 5 The thigh connector 11 has holes 111, 112, and 113 sequentially opened along the axial direction of the mating hole. The thigh connector 2 has holes 121, 122, and 123 sequentially opened along the axial direction of the mating hole. Hole 111 is matched with the size of the large end of the bolt 14, holes 112 and 123 are matched with the size of the small end of the bolt 14, holes 113 and 121 are matched with the size of the spring 13, and hole 122 is matched with the size of the nut. The limiting nut 15 is fixed in the second hole 112, and the bolt 14 slides with the thigh connector 11, thereby limiting the extension and retraction of the spring 13.

[0024] See Figure 2 , Figure 6 , Figure 7 The lower leg assembly 2 includes a lower leg 20 and an ankle drive mechanism mounted on the lower leg 20. The ankle joint 3 includes a first joint frame 31, a second joint frame 32, and a differential support 33. The ankle drive mechanism includes an ankle motor 21, a drive wheel 22, a transmission rope 23, a driven wheel 24, a differential wheel 25, and a differential rope 26. The end of the lower leg 20 facing the second thigh connector 12 is rotatably connected to the second thigh connector 12. Two opposing ankle motors 21 are provided on the inner side of the lower leg 20 or near the second thigh connector 12. The output ends of the two ankle motors 21 are each connected to a drive wheel 22. The lower leg 20 is fixedly connected to a joint frame 31 at the end opposite to the thigh connection 12. The joint frame 31 is rotatably engaged with the differential support 33. The differential support 33 has four connecting shafts fixed circumferentially. The four connecting shafts are arranged in a cross shape, namely the front shaft, rear shaft, left shaft, and right shaft. The joint frame 31 is rotatably engaged with the left and right shafts of the differential support 33. The front and rear shafts of the differential support 33 are rotatably engaged with the joint frame 32.

[0025] Two ankle motors 21 are positioned close to the thigh connector 2 12 to reduce foot mass and rotational inertia, and the transmission rope 23 is arranged in a figure-eight shape.

[0026] Driven wheels 24 are fixedly connected to both the left and right shafts of the differential support 33. Each driven wheel 24 includes a third wheel 241 and a fourth wheel 242, both fixedly connected to the left and right shafts. The size of the driven wheel 24 is larger than that of the driving wheel 22. The driving wheel 22 is connected to the driven wheel 24 via a transmission rope 23. The driving wheel 22 includes a first wheel 221 and a second wheel 222, and the transmission rope 23 includes a first rope 231 and a second rope 232. The first wheel 221 is connected to the driven wheel 24 via the first rope 231. Wheel 3 241 is connected to the drive mechanism. One end of rope 1 231 is wound and fixed to wheel 1 221, and the other end of rope 1 231 is wound and fixed to wheel 3 241. Wheel 2 222 is connected to wheel 4 242 through rope 2 232. One end of rope 2 232 is wound and fixed to wheel 2 222, and the other end of rope 2 232 is wound and fixed to wheel 4 242. It should be noted that the winding and fixing here means that the drive rope 23 is fixed to the driving wheel 22 or the driven wheel 24 and wound around the driving wheel 22 or the driven wheel 24 at least two turns.

[0027] Wheel 5 251 and wheel 6 252 are fixedly connected to the front and rear axles of the differential bracket 33; the driven wheel 24 and the differential wheel 25 are connected by a differential rope 26. The differential wheel 25 includes wheel 5 251 and wheel 6 252, and the differential rope 26 includes rope 3 261, rope 4 262, rope 5 263 and rope 6 264. Among them, wheel 3 241 is connected to wheel 6 252 via rope 3 261. One end of rope 3 261 is fixedly connected to wheel 3 241, and the other end is fixedly connected to wheel 6 252. Wheel 6 252 is connected to wheel 4 242 via rope 4 262. One end of rope 4 262 is fixedly connected to wheel 6 252, and the other end is connected to wheel 4 242. Wheel 3 241 is connected to wheel 5 251 via rope 5 263. One end of rope 5 263 is fixedly connected to one end of wheel 3 241, and the other end is fixedly connected to wheel 5 251. Wheel 4 242 is connected to wheel 5 251 via rope 6 264. One end of rope 6 264 is fixedly connected to wheel 4 242, and the other end is fixedly connected to wheel 5 251. When the two drive wheels 22 rotate in opposite directions, that is, the first wheel 221 and the second wheel 222 rotate in opposite directions, then the third wheel 241 and the fourth wheel 242 rotate in opposite directions. At this time, the foot 4 achieves a roll motion relative to the lower leg assembly 2. For example, if the third wheel 241 rotates clockwise and the fourth wheel 242 rotates counterclockwise, the foot 4 swings to the right. If the third wheel 241 rotates counterclockwise and the fourth wheel 242 rotates clockwise, the foot 4 swings to the left. When the two drive wheels 22 rotate in the same direction, the second joint frame 32 drives the foot 4 to achieve pitch motion relative to the lower leg assembly 2. For example, when the two drive wheels 22 rotate clockwise, the second joint frame 32 drives the foot 4 to rotate clockwise relative to the first joint frame 31. The fifth wheel 251 and the sixth wheel 252 both rotate counterclockwise, and the second joint frame 32 drives the foot 4 to rotate counterclockwise relative to the first joint frame 31.

[0028] See Figure 2 The diameter of the passive wheel 24 is larger than that of the active wheel 22. The rated output torque of the ankle motor 21 is amplified by the wheel diameter ratio, which can generate a large driving torque at the ankle end. The mechanical gain is achieved by using the wheel diameter difference, so that the output of the smaller ankle motor 21 is converted into a larger driving torque of the ankle joint 3 through the rope wheel, thereby meeting the high torque requirements of the robot when walking, lifting, and adjusting its posture. The smaller ankle motor 21 can meet the requirement of compact size.

[0029] It should be noted that the differential rope 26 forms a closed or semi-closed force transmission path under the action of the passive wheel 24 and the differential wheel 25. When the ankle motor 21 performs differential control on different ropes, it can cause the ankle joint 3 to rotate in the corresponding direction, thereby realizing posture correction, balance control and foot compliance adjustment. Through the coordinated drive and the cooperation of different wheel diameter ratios of the passive wheel 24 and the active wheel 22, not only is the output torque improved, but also the accuracy of posture control and dynamic response capability are improved.

[0030] Because the ropes, namely the transmission rope 23 and the differential rope 26, have a certain degree of elasticity, and the pulley system, namely the driving pulley 22, the driven pulley 24, and the differential pulley 25, has a flexible connection characteristic, it can output high torque while also having a certain degree of passive compliance. When the foot collides with the ground or an external object, the slight stretching of the rope and the elastic response of the pulley system can absorb some of the impact energy, avoiding the "hard-on-hard" problem caused by rigid mechanisms and improving the safety and durability of the system. In the robot's gait cycle, the ankle joint 3 exchanges energy during the support and swing phases. Through the flexible energy storage characteristics of the rope system, some elastic potential energy can be temporarily stored during joint movement and released in subsequent actions, thus possessing a certain potential for energy recovery and efficient storage. At the same time, since the main motor, namely the ankle motor 21 and the transmission components, can be arranged on the lower leg 20 or closer to the body, the foot structure can be extremely lightweight, significantly reducing the swing leg inertia and improving gait efficiency and movement flexibility.

[0031] Vertical shock absorption is achieved through the evenly distributed springs 13 of the thigh connector 2 12. The ankle joint 3 achieves high torque output, roll / pitch coordinated drive, lightweight layout, and compliant safety control through the transmission of two ankle motors 21, transmission rope 23, differential rope 26, active wheel 22, passive wheel 24, and differential wheel 25. The two ankle motors 21 drive four differential ropes 26, and the combination of active wheel 22 and passive wheel 24 with different wheel diameter ratios.

[0032] Example 2 The difference between this embodiment and Embodiment 1 is that a constant force load mechanism is added to the thigh assembly 1. This mechanism can apply a reverse pulling force to create a compensating bending moment in the straightening direction of the knee joint, thereby directly offsetting part or all of the bending moment of the knee joint caused by the weight of the lower limbs and achieving static gravity compensation. At the same time, this constant force load mechanism does not undertake all functions alone, but works in conjunction with the motor system as a parallel auxiliary actuator. When the load on the knee joint is large, it shares part of the torque, allowing the motor to work more in the optimal torque range, thereby reducing peak current, reducing heat generation, and improving the overall efficiency. Of course, the constant force load mechanism can also be set in the space adjacent to the thigh assembly 1.

[0033] See Figure 8 , Figure 9 , Figure 10 The thigh assembly 1 and the lower leg assembly 2 are connected by a knee joint. The connection end of the thigh connector 2 12 and the lower leg 20 forms a knee joint. The bottom of the thigh connector 2 12 is fixedly connected to a knee joint drive motor 128. The output end of the knee joint drive motor 128 is fixedly connected to the lower leg 20. The knee joint drive motor 128 can drive the top of the lower leg 20 to rotate around its axis. The constant force load mechanism includes a constant force load spring 124, a transmission wheel 1 125, a load rope 126, and a transmission wheel 2 127.

[0034] A transmission wheel 2 127 is fixedly connected to the lower leg 20. In this embodiment, the transmission wheel 2 127 is located on the side of the lower leg 20. A transmission wheel 1 125 is rotatably connected to the side of the thigh connector 2 12. The transmission wheel 1 125 and the transmission wheel 2 127 are located on the same side. A constant force load spring 124 is fixedly connected to the transmission wheel 1 125. One end of the constant force load spring 124 is fixedly connected to the transmission wheel 1 125, and the other end of the constant force load spring 124 is wound and fixed with the load rope 126 and the transmission wheel 2 127.

[0035] It should be noted that the constant force load spring 124 in this embodiment is a CFS constant force load spring, which is arranged in a coiled manner. One end of the load rope 126 is connected to the CFS constant force load spring, and the other end is connected to the knee joint assist end, i.e., the second transmission wheel 127. When the spring is released or coiled, the direction of force transmission and the lever arm relationship are changed through the constant force load spring 124, the first transmission wheel 125, the load rope 126, and the second transmission wheel 127, so as to convert the constant force into an assist torque that is more suitable for the knee joint, thereby providing a stable straightening compensation force to the knee joint. At the same time, it can continuously output an approximately constant assist according to the change of knee joint angle, reducing the fluctuation of assist caused by changes in posture.

[0036] During operation, when the knee joint tends to bend due to the weight of the lower limb or external load, the constant force load spring 124 applies a reverse tension through the constant force load mechanism, generating a compensating bending moment in the straightening direction of the knee joint. This directly offsets part or all of the bending moment caused by the weight of the lower limb, achieving static gravity compensation. Simultaneously, the constant force load spring 124 does not perform all functions alone. Instead, it works in conjunction with the knee joint drive motor 128 as a parallel auxiliary actuator. When the knee joint load is high, it shares some of the torque, allowing the motor to operate more within its optimal torque range, thereby reducing peak current, decreasing heat generation, and improving overall efficiency.

[0037] The transmission rope 23 and differential rope 26 have a certain elastic modulus and together with the constant force load spring 124, they form a double buffer structure. When the knee joint movement undergoes rapid start-stop, sudden load change, or unloading, the transmission rope 23, differential rope 26, drive wheel 22, driven wheel 24, and differential wheel 25 can first absorb a portion of the transient impact. The constant force load spring 124 then further smooths the load change through its continuous release or retraction capability, thereby reducing the instantaneous impact force on the knee joint drive motor 128 and the joint. In addition, during the joint rotation process, some gravitational potential energy can be converted into elastic potential energy and stored in the constant force load spring 124, which is released in the next action stage, realizing a certain degree of energy recovery and reuse.

[0038] By utilizing the near-constant output characteristics of the constant force load spring 124 and the flexible transmission characteristics of the transmission rope 23 and the differential rope 26, the dynamic damping during the knee joint movement can be mechanically adjusted, thereby suppressing joint vibration, reducing shaking and overshoot, and improving the smoothness and stability of the movement. The overall structure can achieve multiple effects such as continuous assistance, precise gravity compensation, impact buffering, energy recovery and stable control in a small installation space.

[0039] Example 3 The difference between this embodiment and Embodiments 1 and 2 is that this embodiment provides a robot that includes the lower limb auxiliary drive mechanism in Embodiment 1 or Embodiment 2.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A lower limb auxiliary drive mechanism, comprising a thigh assembly and a lower leg assembly connected to the thigh assembly, wherein the connection end of the thigh connector and the lower leg assembly forms a knee joint, characterized in that, The thigh assembly includes a thigh connector 1 and a thigh connector 2 connected by a spring. The thigh connector 2 is equipped with a constant force load mechanism, which includes a transmission wheel 1 and a transmission wheel 2. A knee joint drive motor is fixedly connected to the end of the thigh connector 2. The output end of the knee joint drive motor is fixedly connected to the lower leg assembly and can drive the lower leg assembly to rotate. The thigh connector 2 is rotatably connected to the transmission wheel 1, which is equipped with a constant force load spring. The coiled spring is connected to the transmission wheel 2 fixed to the lower leg assembly through a load rope. The constant force load mechanism can share part of the torque and can counteract the bending moment generated by the weight of the lower limb on the knee joint.

2. The lower limb auxiliary drive mechanism according to claim 1, characterized in that, One end of the load rope is fixedly connected to the constant force load spring, and the other end is wound and fixed to the transmission wheel.

3. The lower limb auxiliary drive mechanism according to claim 1, characterized in that, It also includes the ankle joint and the foot. The end of the lower leg assembly away from the thigh assembly is movably connected to the foot through a differential bracket of the ankle joint. The lower leg assembly includes the lower leg and two ankle motors fixed on the lower leg. The output end of each of the two ankle motors is driven by a drive wheel. The two opposite ends of the differential bracket are rotatably connected to a driven wheel. The diameter of the driven wheel is larger than that of the drive wheel. The other opposite ends are rotatably connected to a differential wheel. The two drive wheels are each driven by a drive rope and a driven wheel. The two driven wheels are driven by a differential rope and the two differential wheels. Driving the two drive wheels to rotate in opposite directions can drive the foot to roll relative to the lower leg assembly. Driving the two drive wheels to rotate in the same direction can drive the foot to pitch relative to the lower leg assembly.

4. The lower limb auxiliary drive mechanism according to claim 3, characterized in that, The differential support is circumferentially fixed with a front axle, rear axle, left axle, and right axle arranged in a cross shape. A passive wheel is fixedly connected to the left axle and the right axle, and a differential wheel is fixedly connected to the front axle and the rear axle. The ankle joint includes a joint frame one and a joint frame two. One end of the joint frame is fixedly connected to the lower leg assembly, and the other end is rotatably connected to the left axle and the right axle. One end of the joint frame two is fixedly connected to the foot, and the other end is rotatably connected to the front axle and the rear axle.

5. The lower limb auxiliary drive mechanism according to claim 3, characterized in that, The driven pulley includes pulley three and pulley four, the differential pulley includes pulley five and pulley six, and the differential rope includes rope three, rope four, rope five and rope six. Pulley three is connected to pulley six via rope three, pulley six is ​​connected to pulley four via rope four, pulley three is connected to pulley five via rope five, and pulley four is connected to pulley five via rope six.

6. The lower limb auxiliary drive mechanism according to claim 5, characterized in that, The driving pulley includes pulley one and pulley two, and the transmission rope includes rope one and rope two. Pulley one is connected to pulley three through rope one, and pulley two is connected to pulley four through rope two.

7. The lower limb auxiliary drive mechanism according to claim 3, characterized in that, The connecting surfaces of leg connector 1 and thigh connector 2, as well as the connecting surfaces of thigh connector 2 and thigh connector 1, are provided with evenly arranged mating holes. Springs are placed in the mating holes, and thigh connector 1 is elastically connected to thigh connector 2 through the springs.

8. The lower limb auxiliary drive mechanism according to claim 7, characterized in that, The thigh connector has a limit nut for internal fixation, and a bolt for sliding connection on the thigh connector, which is threaded to the limit nut.

9. The lower limb auxiliary drive mechanism according to claim 8, characterized in that, The first thigh connector has holes 1, 2, and 3 sequentially opened along the axial direction of its mating holes. The second thigh connector has holes 4, 5, and 6 sequentially opened along the axial direction of its mating holes. Hole 1 is matched with the size of the large end of the bolt, holes 2 and 6 are matched with the size of the small end of the bolt, holes 3 and 4 are matched with the size of the spring, and hole 5 is matched with the size of the nut.

10. A robot, characterized in that, Includes the lower limb drive mechanism as described in any one of claims 1-9.

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