Leg structure of wire-driven biped robot

Abstract

The invention discloses a line drive type biped robot leg structure which comprises a thigh support, a knee joint motor is arranged at the lower end of the thigh support, a shank support is connected to an output shaft of the knee joint motor, a foot assembly is movably connected to the lower end of the shank support and comprises a foot fixing piece, and a heel is connected to the rear portion of the foot fixing piece. The heel is connected with a line driving structure, the line driving structure comprises a first ankle joint motor, a second ankle joint motor, a first driving line wheel, a second driving line wheel, a first ankle joint line wheel and a second ankle joint line wheel, and a first transmission line is arranged between the first driving line wheel and the first ankle joint line wheel; a second transmission line is arranged between the second driving line wheel and the second ankle joint line wheel, a first crank swing rod structure is arranged between the first ankle joint line wheel and one side of the heel, and a second crank swing rod structure is arranged between the second ankle joint line wheel and the other side of the heel. The device has the advantages of being simple in structure and good in adaptability.

Description

Technical Field

[0001] The invention relates to the technical field of biped robots, and in particular to a wire-driven biped robot leg structure. Background Art

[0002] In traditional bipedal robot designs, ankle motors are generally installed in the calf. This design increases the mass and moment of inertia of the calf. Large leg inertia directly affects the dynamic performance of the robot, such as reducing movement speed and acceleration, and increasing energy consumption. In addition, large leg inertia also places higher requirements on the robot's balance control system, making the robot more likely to lose stability when moving quickly or subject to external interference, thereby limiting its application in complex environments.

[0003] Secondly, existing bipedal robots usually use multiple motors to drive each joint, which makes the mechanical structure of the joint area quite complicated. This complex structure not only increases the manufacturing cost and maintenance difficulty of the robot, but also makes it prone to mechanical failure. In addition, due to the limitations of the motor and transmission mechanism, the stiffness of the joints is usually large, making it difficult to achieve smooth and natural movements like humans. High-stiffness joints also limit the flexibility of the robot when interacting with the environment, such as difficulty in adapting to uneven terrain or absorbing impact.

[0004] Finally, the foot design of most traditional bipedal robots adopts fixed stiffness and cannot be adjusted according to different ground environments. This makes it difficult for robots to maintain stability and efficient movement when facing complex terrains, such as soft grass, hard rocks or uneven roads.

[0005] Therefore, it is necessary to further improve and perfect the prior art to overcome these shortcomings, and the present invention is made based on this situation. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a wire-driven biped robot leg structure with simple structure and good adaptability.

[0007] The present invention is achieved through the following technical solutions:

[0008] To solve the above technical problems, the present invention provides a wire-driven bipedal robot leg structure, comprising a thigh support, a knee joint motor is provided at the lower end of the thigh support, a calf support is connected to the output shaft of the knee joint motor, a foot assembly is movably connected to the lower end of the calf support, the foot assembly comprises a foot fixing member universally connected to the lower end of the calf support, a heel is fixedly connected to the rear of the foot fixing member, the heel is connected to a wire-driven structure, the wire-driven structure comprises a first ankle joint motor and a second ankle joint motor provided on the thigh support, a first driving wire wheel is provided on the output shaft of the first ankle joint motor, a second driving wire wheel is provided on the output shaft of the second ankle joint motor, a first ankle joint wire wheel and a second ankle joint wire wheel rotatably connected to the calf support, a first transmission line for transmission connection between the first driving wire wheel and the first ankle joint wire wheel, a second transmission line for transmission connection between the second driving wire wheel and the second ankle joint wire wheel, a first crank swing rod structure is provided between the first ankle joint wire wheel and one side of the heel, and a second crank swing rod structure is provided between the second ankle joint wire wheel and the other side of the heel.

[0009] In order to further solve the technical problem to be solved by the present invention, in a wire-driven bipedal robot leg structure provided by the present invention, a first relay wheel and a second relay wheel are provided on the thigh support, the first transmission line passes through the first relay wheel, and the second transmission line passes through the second relay wheel.

[0010] In order to further solve the technical problem to be solved by the present invention, in a wire-driven biped robot leg structure provided by the present invention, the first relay pulley and the second relay pulley are both coaxial with the output shaft of the knee joint motor.

[0011] In order to further solve the technical problem to be solved by the present invention, in a wire-driven bipedal robot leg structure provided by the present invention, the first crank rocker structure includes a first eccentric column arranged on a first ankle joint wire wheel, and a first shaft head arranged on one side of the heel, a first transmission rod is arranged between the first eccentric column and the first shaft head, and both ends of the first transmission rod are provided with a first universal joint for connecting to the first eccentric column or the first shaft head.

[0012] In order to further solve the technical problem to be solved by the present invention, in a wire-driven bipedal robot leg structure provided by the present invention, the second crank rocker structure includes a second eccentric column arranged on the second ankle joint pulley, and a second shaft head arranged on the other side of the heel, a second transmission rod is arranged between the second eccentric column and the second shaft head, and second universal joints are arranged at both ends of the second transmission rod for connecting to the second eccentric column or the second shaft head.

[0013] In order to further solve the technical problem to be solved by the present invention, in a wire-driven biped robot leg structure provided by the present invention, the first shaft head and the second shaft head are coaxial.

[0014] In order to further solve the technical problem to be solved by the present invention, in a wire-driven biped robot leg structure provided by the present invention, a universal joint for universally connecting the foot fixing member and the lower end of the calf support is provided between the foot fixing member and the lower end of the calf support.

[0015] In order to further solve the technical problem to be solved by the present invention, in a wire-driven bipedal robot leg structure provided by the present invention, the foot component also includes an arch arranged in front of a foot fixing member, the front end of the arch is rotatably connected to a sole that can swing up and down, the rear part of the sole is rotatably connected to a first connecting rod, the rear end of the first connecting rod is rotatably connected to a second connecting rod and a driving rod, the other end of the second connecting rod is rotatably connected to the foot fixing member, and the other end of the driving rod extends upward and a damping assembly is provided between the calf.

[0016] In order to further solve the technical problem to be solved by the present invention, in a wire-driven bipedal robot leg structure provided by the present invention, the damping assembly includes a third universal joint arranged at the upper end of the driving rod, the third universal joint is connected to a sleeve, the sleeve is slidably connected to the calf support along the up and down directions, the sleeve is provided with a damping spring and a piston that can press the damping spring downward, the piston is connected to a rotating rod, and the rotating rod is fixed relative to the calf support.

[0017] In order to further solve the technical problem to be solved by the present invention, in a wire-driven bipedal robot leg structure provided by the present invention, the piston and the rotating rod are connected by a thread, and the rotating rod is connected to a stiffness adjustment motor for driving the rotating rod to rotate and then drive the piston to rise and fall.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. The present invention effectively reduces the inertia of the leg and improves the robot's movement flexibility and gait stability by moving the ankle joint motor up to the thigh and controlling the ankle joint by wire drive. At the same time, the wire drive structure simplifies the mechanical structure of the joint area and provides more space for the integration of other sensors or components. In addition, the inherent elastic properties of the wire drive system can enhance the cushioning capacity of the ankle, reduce the impact force on the ground, and improve the interaction performance between the robot and the ground, thereby improving the robot's adaptability in complex environments.

[0020] 2. The foot assembly of the present invention has a variable stiffness sole structure, and the stiffness of the sole can be adjusted in real time by adjusting the preload of the damping spring by the motor. This design enables the robot to dynamically adjust the stiffness of the foot according to different terrains and task requirements, thereby improving the grip and stability on various ground surfaces, reducing energy consumption, achieving a more supple and natural gait, and enhancing the adaptability to perform various tasks. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings, wherein:

[0022] Figure 1 It is one of the three-dimensional structural schematic diagrams of the present invention;

[0023] Figure 2 It is an exploded schematic diagram of the present invention;

[0024] Figure 3 is a cross-sectional view of the damping assembly;

[0025] Figure 4 It is an exploded schematic diagram of the foot assembly;

[0026] Figure 5 is a cross-sectional view of the foot assembly;

[0027] Figure 6 This is the second schematic diagram of the three-dimensional structure of the present invention (the calf support is not shown). DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0029] like Figures 1 to 6 As shown, this embodiment provides a wire-driven biped robot leg structure, which aims to solve the problems of large leg inertia, complex joints, poor foot adaptability, etc. in the prior art. The structure mainly includes a thigh support 1, a knee joint motor 2, a calf support 3, a foot assembly 4 and a wire drive structure 5.

[0030] The thigh bracket 1 is the main supporting structure of the robot leg, and its lower end is connected to the knee joint motor 2. The output shaft of the knee joint motor 2 is connected to the calf bracket 3 to achieve the flexion and extension of the knee joint. The lower end of the calf bracket 3 is connected to the foot component 4 through a universal joint, giving the foot a certain posture adjustment ability.

[0031] The foot assembly 4 includes a foot fixing member 41 and a heel 42. The foot fixing member 41 is connected to the lower end of the calf support 3 through a universal connection, ensuring a flexible connection between the foot and the calf. The heel 42 is fixedly connected to the rear of the foot fixing member 41 and serves as a connection point for the line drive structure 5.

[0032] The wire drive structure 5 is the core of the present invention, which moves the ankle joint motor up to the thigh support 1, thereby reducing the inertia of the leg end. The wire drive structure 5 is mainly composed of a first ankle joint motor 51, a second ankle joint motor 52, a first drive wire wheel 511, a second drive wire wheel 521, a first ankle joint wire wheel 53, a second ankle joint wire wheel 54, a first transmission line 55, a second transmission line 56, a first crank swing rod structure 57, and a second crank swing rod structure 58.

[0033] The first ankle joint motor 51 and the second ankle joint motor 52 are respectively installed on the thigh support 1, and their output shafts are respectively connected to the first drive wire wheel 511 and the second drive wire wheel 521. The first transmission line 55 connects the first drive wire wheel 511 and the first ankle joint wire wheel 53, and the second transmission line 56 connects the second drive wire wheel 521 and the second ankle joint wire wheel 54. The first ankle joint wire wheel 53 and the second ankle joint wire wheel 54 are rotatably connected to the calf support 3. The rotation of the first ankle joint motor 51 and the second ankle joint motor 52 drives the drive wire wheel to rotate, and then drives the ankle joint wire wheel to rotate through the transmission line, and finally realizes the pitch and inversion and eversion movement of the foot.

[0034] In order to convert the rotational motion of the wire wheel into the swinging motion of the foot, the present invention also designs a crank swing rod structure. The first crank swing rod structure 57 connects the first ankle joint wire wheel 53 and one side of the heel 42, and the second crank swing rod structure 58 connects the second ankle joint wire wheel 54 and the other side of the heel 42. This design enables the ankle joint motor to drive the heel 42 through the crank swing rod structure when driving the wire wheel to rotate, thereby realizing the flexible movement of the ankle joint.

[0035] This embodiment effectively reduces the inertia of the leg by moving the ankle motor up to the thigh and controlling the ankle joint by wire drive, thereby improving the robot's movement flexibility and gait stability. At the same time, the wire drive structure simplifies the mechanical structure of the joint area and provides more space for the integration of other sensors or components. In addition, the inherent elastic properties of the wire drive system can enhance the cushioning capacity of the ankle, reduce the impact force on the ground, and improve the interaction performance between the robot and the ground, thereby improving the robot's adaptability in complex environments.

[0036] In order to further optimize the transmission efficiency and layout of the wire drive system, the present invention improves the wire drive structure on the basis of the embodiment. A first relay pulley 551 and a second relay pulley 561 are set on the thigh support 1. The first transmission line 55 bypasses the first relay pulley 551, and the second transmission line 56 bypasses the second relay pulley 561. This design can change the direction of the transmission line, make the layout of the wire drive system more reasonable, avoid entanglement and interference between lines, and adjust the transmission ratio as needed to optimize the torque output.

[0037] A more preferred solution is to set the first relay line wheel 551 and the second relay line wheel 561 to be coaxial with the output shaft of the knee joint motor 2. This coaxial design can effectively prevent the transmission line from getting entangled during the movement of the knee joint, and ensure the stability and reliability of the line drive system.

[0038] The specific implementation method of the crank rocker structure is described in detail below.

[0039] The first crank rocker structure 57 is composed of the following components: a first eccentric column 531 fixed on the first ankle joint line wheel 53, a first shaft head 421 arranged on one side of the heel 42, and a first transmission rod 571 connecting the first eccentric column 531 and the first shaft head 421. In order to achieve flexible rotation connection, first universal joints 572, such as ball bearings, are respectively provided at both ends of the first transmission rod 571 for connecting with the first eccentric column 531 and the first shaft head 421.

[0040] The second crank swing structure 58 is similar to the first crank swing structure 57, and includes: a second eccentric column 541 fixed to the second ankle joint line wheel 54, a second shaft head 422 arranged on the other side of the heel 42, and a second transmission rod 581 connecting the second eccentric column 541 and the second shaft head 422. Similarly, the second transmission rod 581 is also provided with a second universal joint 582 at both ends, such as a ball bearing, for connecting with the second eccentric column 541 and the second shaft head 422.

[0041] Through the design of this crank swing rod structure, when the ankle joint line wheel rotates, the eccentric column drives the transmission rod to move, and then drives the heel to rotate around the shaft head, realizing the pitch and inversion and eversion movement of the ankle joint. The use of the universal joint ensures the flexibility of the transmission rod during the movement, and can adapt to a certain degree of misalignment and deformation, thereby improving the reliability and durability of the mechanism.

[0042] A more preferred solution is to design the first shaft head 421 and the second shaft head 422 to be coaxial. This coaxial design can effectively simplify the structure of the heel, reduce the number of parts, and improve assembly accuracy. At the same time, the coaxial design can also ensure the stability of the rotation center of the heel, avoid shaking or offset, thereby improving the accuracy and stability of the ankle joint movement and making the torque transmission more efficient.

[0043] The specific implementation of the foot component is described in detail below.

[0044] The foot assembly 4 comprises a foot fixing member 41, which is connected to the lower end of the calf support 3 via a universal joint 43. The universal joint 43 enables the foot assembly to move with multiple degrees of freedom relative to the calf, so that it can adapt to different terrains and postures.

[0045] The front part of the foot fixing member 41 is provided with an arch 44, which is generally arc-shaped and gradually lowers from the back to the front. The front end of the arch 44 is rotatably connected to the sole 45 that can swing up and down. This design simulates the arch structure of the human foot and can provide a certain cushioning and support effect.

[0046] A first connecting rod 46 is provided at the rear of the sole 45, the front end of the first connecting rod 46 is rotatably connected to the sole 45, and the rear end of the first connecting rod 46 is rotatably connected to the second connecting rod 47 and the driving rod 48. The other end of the second connecting rod 47 is rotatably connected to the foot fixing member 41 to form a four-bar linkage. The driving rod 48 extends upward and is connected to the calf support 3 through the damping assembly 49.

[0047] The damping assembly 49 is a key component for achieving variable stiffness. It includes a third universal joint 491 fixed to the upper end of the driving rod 48, a sleeve 492, a damping spring 493, a piston 494, a rotating rod 495 and a stiffness adjustment motor 496. The sleeve 492 slides up and down along the calf support 3, and a damping spring 493 and a piston 494 are installed inside. The piston 494 is connected to the rotating rod 495, and the rotating rod 495 is connected to the stiffness adjustment motor 496 through a coupling, and the stiffness adjustment motor 496 is fixed on the calf support 3. The piston 494 and the rotating rod 495 are connected by a threaded connection, and when the rotating rod 495 rotates, the piston 494 can move up and down. By driving the rotating rod 495 to rotate through the stiffness adjustment motor 496, the piston 494 can be controlled to move up and down in the sleeve 492, thereby changing the pre-compression amount of the damping spring 493, and then adjusting the stiffness of the sole of the foot.

[0048] The advantages of this variable stiffness sole structure are:

[0049] 1) Adapt to different terrains: By adjusting the stiffness of the soles, the robot can better adapt to various terrains. On soft ground, reducing stiffness can increase the contact area, improve grip and stability; on hard ground, increasing stiffness can ensure efficient force transmission.

[0050] 2) Energy storage and release: The variable stiffness foot can store and release energy like a spring, thereby reducing the energy consumption of the actuator and improving the energy efficiency of the robot's walking.

[0051] 3) Flexible gait: By adjusting the stiffness of the sole of the foot, a flexible gait can be better achieved, imitating the natural movement of organisms, reducing the adverse effects of ground reaction force, and making the movement smoother.

[0052] 4) Adapt to different task requirements: When carrying heavy objects, higher stiffness is required to provide stable support; when performing delicate tasks or collaborative tasks, the stiffness can be reduced to achieve more precise and compliant interactions.

[0053] In summary, this foot component design, especially the variable stiffness structure, significantly improves the robot's environmental adaptability, movement efficiency, and task execution capabilities, enabling it to better cope with complex and changing application scenarios.

Claims

1. A wire-driven biped robot leg structure, characterized in that: The invention comprises a thigh support (1), wherein a knee joint motor (2) is provided at the lower end of the thigh support (1), a calf support (3) is connected to the output shaft of the knee joint motor (2), a foot assembly (4) is movably connected to the lower end of the calf support (3), the foot assembly (4) comprises a foot fixing member (41) universally connected to the lower end of the calf support (3), a heel (42) is fixedly connected to the rear of the foot fixing member (41), the heel (42) is connected to a wire drive structure (5), the wire drive structure (5) comprises a first ankle joint motor (51) and a second ankle joint motor (52) provided on the thigh support (1), a first drive wire wheel (511) provided on the output shaft of the first ankle joint motor (51), and a wire drive structure (55) provided on the lower end of the foot fixing member (41). A second driving wire wheel (521), a first ankle wire wheel (53) and a second ankle wire wheel (54) rotatably connected to the calf support (3) are provided on the output shaft of the second ankle joint motor (52), and a first transmission line (55) for transmission connection between the first driving wire wheel (511) and the first ankle wire wheel (53) is provided, a second transmission line (56) for transmission connection between the second driving wire wheel (521) and the second ankle wire wheel (54) is provided, a first crank swing rod structure (57) is provided between the first ankle wire wheel (53) and one side of the heel (42), and a second crank swing rod structure (58) is provided between the second ankle wire wheel (54) and the other side of the heel (42).

2. The wire-driven biped robot leg structure according to claim 1, characterized in that: The thigh support (1) is provided with a first relay line wheel (551) and a second relay line wheel (561), the first transmission line (55) passes through the first relay line wheel (551), and the second transmission line (56) passes through the second relay line wheel (561).

3. The wire-driven biped robot leg structure according to claim 2, characterized in that: The first relay line wheel (551) and the second relay line wheel (561) are both coaxial with the output shaft of the knee joint motor (2).

4. The wire-driven biped robot leg structure according to claim 1, characterized in that: The first crank rocker structure (57) comprises a first eccentric column (531) arranged on a first ankle joint line wheel (53), and a first shaft head (421) arranged on one side of the heel (42); a first transmission rod (571) is arranged between the first eccentric column (531) and the first shaft head (421); and first universal joints (572) for connecting to the first eccentric column (531) or the first shaft head (421) are arranged at both ends of the first transmission rod (571).

5. The wire-driven biped robot leg structure according to claim 4, characterized in that: The second crank rocker structure (58) comprises a second eccentric column (541) arranged on the second ankle joint line wheel (54), and a second shaft head (422) arranged on the other side of the heel (42); a second transmission rod (581) is arranged between the second eccentric column (541) and the second shaft head (422); and second universal joints (582) for connecting to the second eccentric column (541) or the second shaft head (422) are arranged at both ends of the second transmission rod (581).

6. The wire-driven biped robot leg structure according to claim 5, characterized in that: The first shaft head (421) and the second shaft head (422) are coaxial.

7. The wire-driven biped robot leg structure according to claim 1, characterized in that: A universal joint (43) for universally connecting the foot fixing member (41) and the lower end of the calf support (3) is provided between the foot fixing member (41) and the lower end of the calf support (3).

8. The wire-driven biped robot leg structure according to claim 1, characterized in that: The foot component (4) also includes an arch (44) arranged in front of the foot fixing member (41), the front end of the arch (44) is rotatably connected to a sole (45) that can swing up and down, the rear part of the sole (45) is rotatably connected to a first connecting rod (46), the rear end of the first connecting rod (46) is rotatably connected to a second connecting rod (47) and a driving rod (48), the other end of the second connecting rod (47) is rotatably connected to the foot fixing member (41), and the other end of the driving rod (48) extends upward and a damping component (49) is provided between the calf.

9. The wire-driven biped robot leg structure according to claim 8, characterized in that: The damping assembly (49) includes a third universal joint (491) arranged at the upper end of the driving rod (48), the third universal joint (491) is connected to a sleeve (492), the sleeve (492) is slidably connected to the calf support (3) along the up and down directions, the sleeve (492) is provided with a damping spring (493) and a piston (494) that can press the damping spring (493) downward, the piston (494) is connected to a rotating rod (495), and the rotating rod (495) is fixed relative to the calf support (3).

10. The wire-driven biped robot leg structure according to claim 9, characterized in that: The piston (494) and the rotating rod (495) are connected via threads, and the rotating rod (495) is connected to a stiffness adjustment motor (496) for driving the rotating rod (495) to rotate and thereby drive the piston (494) to rise and fall.

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