Biped robot leg structure

Abstract

The invention discloses a biped robot leg structure which comprises a center base, a hip joint flexion and extension motor, a hip joint abduction motor, a hip joint internal and external rotation motor, a knee joint motor and a shank component, the shank component comprises a shank support and a foot, and the shank support is provided with a first ankle joint motor and a second ankle joint motor; a universal joint is arranged between the foot and the shank support, a first crank rocker mechanism is arranged between the first ankle joint motor and the foot, and a second crank rocker mechanism is arranged between the second ankle joint motor and the foot. A driving rod is transversely arranged at the rear part of the foot; the first crank rocker mechanism comprises a first rotating disc, a first eccentric column is arranged on the first rotating disc, a relay rotating disc is rotationally connected to the shank support, a second eccentric column and a third eccentric column are arranged on the relay rotating disc, a connecting rod is arranged between the second eccentric column and the first eccentric column, and a first universal connecting rod is arranged between the third eccentric column and the driving rod. The invention has the advantages of flexibility, small volume and low energy loss.

Description

Technical Field

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

[0002] The leg structure of traditional bipedal robots is too rigid, which leads to lack of flexibility, excessive size, reduced ability to absorb external disturbances during movement, and difficulty in coping with uneven terrain or dynamic environments. Structures with high rigidity will also increase energy consumption, especially when frequent posture adjustments or high-dynamic movements such as jumping are required. Excessive rigidity may cause the leg structure to vibrate easily during rapid movement. Vibration will not only reduce the accuracy of the robot's movement, but may also cause fatigue or damage to other structural components, affecting the life of the structure.

[0003] Furthermore, the traditional bipedal robot leg transmission mechanism usually adopts a long rod direct connection method, which easily causes the rod to deform, thus affecting the torque transmission accuracy and the accuracy of foot movement. In addition, the long rod has a large inertia, which will also affect the dynamic performance and control accuracy of the robot. At the same time, the long rod is easy to interfere with other components in the limited leg space, limiting the robot's range of motion. In order to solve these problems, researchers have been exploring new leg structure design solutions. Some studies have tried to use parallel mechanisms or series-parallel hybrid mechanisms to improve the torque transmission efficiency and mechanism stiffness, but these mechanisms are usually complex in structure and the control algorithm is also relatively complex.

[0004] In addition, most existing bipedal robot foot designs use a simple flat plate structure, which lacks effective absorption of ground impact and easily causes damage to the robot joints and motors. Therefore, developing a foot structure that can effectively absorb ground impact and improve buffering performance is also an important direction for bipedal robot research.

[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 bipedal robot leg structure which is more flexible, smaller in size and has lower energy consumption.

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

[0008] To solve the above technical problems, the present invention provides a bipedal robot leg structure, comprising a central base, the central base is connected to a hip flexion and extension motor, the output shaft of the hip flexion and extension motor is provided with a hip abduction motor, and the central axes of the two are perpendicular to each other, the output shaft of the hip abduction motor is provided with a hip internal and external rotation motor, and the central axes of the two are perpendicular to each other, the output shaft of the hip internal and external rotation motor is provided with a knee joint motor, and the central axes of the two are perpendicular to each other; a calf assembly is provided on the output shaft of the knee joint motor, the calf assembly comprises a calf support and a foot, the calf support is provided with a first ankle joint motor and a second ankle joint motor, a universal joint movably connecting the two is provided between the foot and the lower part of the calf support, a first crank rocker mechanism is provided between the first ankle joint motor and the foot, and a second crank rocker mechanism is provided between the second ankle joint motor and the foot;

[0009] The rear part of the foot is provided with a horizontal driving rod, the first crank rocker mechanism is provided between the first ankle joint motor and one end of the driving rod, and the second crank rocker mechanism is provided between the second ankle joint motor and the other end of the driving rod; the output power of the first ankle joint motor and the second ankle joint motor is transmitted to the driving rod with coaxial output through two sets of crank rocker mechanisms, so as to realize the two-degree-of-freedom movement of the ankle joint;

[0010] The first crank rocker mechanism includes a first turntable arranged on the output shaft of the first ankle joint motor, a first eccentric column is arranged on the first turntable, a relay turntable is rotatably connected to the calf support, a second eccentric column and a third eccentric column are arranged opposite to each other on the relay turntable, a connecting rod is arranged between the second eccentric column and the first eccentric column, and a first universal connecting rod is arranged between the third eccentric column and one end of the driving rod.

[0011] In order to further solve the technical problem to be solved by the present invention, in a bipedal robot leg structure provided by the present invention, the second crank rocker mechanism includes a second turntable arranged on the output shaft of the second ankle joint motor, a fourth eccentric column is arranged on the second turntable, and a second universal connecting rod is arranged between the other ends of the fourth eccentric column driving rod.

[0012] In order to further solve the technical problem to be solved by the present invention, in a biped robot leg structure provided by the present invention, the rotation radius of the first eccentric column and the second eccentric column are the same.

[0013] In order to further solve the technical problem to be solved by the present invention, in a biped robot leg structure provided by the present invention, the fourth eccentric column and the third eccentric column have the same rotation axis and the same rotation radius.

[0014] In order to further solve the technical problem to be solved by the present invention, in a biped robot leg structure provided by the present invention, the first ankle joint motor and the second ankle joint motor are arranged up and down.

[0015] In order to further solve the technical problem to be solved by the present invention, the present invention provides a biped robot leg structure, wherein a central axis is provided at the rear of the foot, and the driving rod is provided at the end of the central axis.

[0016] In order to further solve the technical problem to be solved by the present invention, in a biped robot leg structure provided by the present invention, the first universal connecting rod includes a first rod body, and both ends of the first rod body are connected to first rod end joint bearings through threads.

[0017] In order to further solve the technical problem to be solved by the present invention, in a biped robot leg structure provided by the present invention, the second universal connecting rod includes a second rod body, and both ends of the second rod body are connected to second rod end joint bearings through threads.

[0018] In order to further solve the technical problem to be solved by the present invention, the present invention provides a biped robot leg structure, wherein the foot is a bow-shaped structure.

[0019] In order to further solve the technical problem to be solved by the present invention, in a bipedal robot leg structure provided by the present invention, the bottom of the foot is detachably connected to a flexible sole.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The present invention uses a relay turntable as a force transmission node to replace the traditional long rod direct connection method, effectively solving the problems of easy deformation of the long rod, large inertia, and spatial interference. This innovative design not only improves the torque transmission accuracy and foot movement accuracy, but also reduces the inertia effect, improves the dynamic performance and response speed of the robot. In addition, the introduction of the relay turntable also increases the compactness and adjustability of the mechanism design, enabling the robot to better adapt to different terrains and movement requirements, and ultimately improves its overall performance and practicality.

[0022] 2. The bipedal robot leg structure of the present invention uses two crank rocker mechanisms to transmit the output power of the two ankle joint motors to the coaxial output drive rod to drive the foot movement, thereby realizing the two-degree-of-freedom movement of the ankle joint, reducing the space occupied by the ankle joint, and improving the compactness of the leg structure. This design optimizes the torque transmission path, improves the driving efficiency, reduces the complexity of the control algorithm, improves the real-time performance and stability of the control system, and is easy to standardize and modularize, which is convenient for later maintenance and upgrading.

[0023] 3. The present invention adopts a coaxial design, so that the first and second eccentric columns and the third and fourth eccentric columns are coaxial and have the same rotation radius, and the relay turntable is coaxial with the second turntable, and the connecting rods are of the same length and symmetrical. This design greatly simplifies the mechanical model, reduces the complexity of motion analysis and control algorithms, significantly reduces space occupancy, improves structural compactness, and ultimately improves the control efficiency and overall performance of the robot.

[0024] 4. The bipedal robot foot of the present invention adopts an arch structure, simulating the mechanical properties of the human arch, and with a detachable sole pad, it can effectively absorb ground impact force, provide better cushioning performance, reduce the impact on the joints and motors when the robot walks or runs, and extend its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings, wherein:

[0026] Figure 1 It is a three-dimensional structural schematic diagram of the present invention;

[0027] Figure 2 It is an exploded schematic diagram of the present invention;

[0028] Figure 3 It is an exploded schematic diagram of the lower leg assembly;

[0029] Figure 4 is a side view of the foot. DETAILED DESCRIPTION

[0030] 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.

[0031] like Figures 1 to 4 As shown, the present invention provides a bipedal robot leg structure, including a central base 1. The central base 1 is sequentially connected with a hip flexion and extension motor 2, a hip abduction motor 3, and a hip internal and external rotation motor 4, and the central axes of the three motors are perpendicular to each other to form a series structure to achieve three degrees of freedom of the hip joint. Specifically, the hip flexion and extension motor 2 is fixed on the central base 1, and its output shaft is connected to the hip abduction motor 3 to control the forward and backward swing of the leg; the output shaft of the hip abduction motor 3 is connected to the hip internal and external rotation motor 4 to control the left and right swing of the leg; the output shaft of the hip internal and external rotation motor 4 is connected to the knee joint motor 5 to control the rotational movement of the leg.

[0032] The central axis of the knee joint motor 5 is perpendicular to the output axis of the hip joint internal and external rotation motor 4, and controls the flexion and extension of the calf assembly 6. The output axis of the knee joint motor 5 is connected to the calf assembly 6, which includes a calf support 61 and a foot 62.

[0033] The first ankle joint motor 63 and the second ankle joint motor 64 are installed on the calf support 61 to control the movement of the foot 62. The foot 62 is movably connected to the lower part of the calf support 61 through a universal joint 65, and the universal joint 65 enables the foot 62 to perform multi-directional rotational movement.

[0034] In order to realize the two-degree-of-freedom movement of the ankle joint and optimize the torque transmission, the present invention uses two crank mechanisms to connect the ankle joint motor and the foot. Specifically, the first ankle joint motor 63 is connected to the foot 62 through the first crank rocker mechanism 66, and the second ankle joint motor 64 is connected to the foot 62 through the second crank rocker mechanism 67.

[0035] like Figure 3-Figure 4 As shown, a central axis 621 is provided at the rear of the foot 62, and a transverse driving rod 622 is provided at the end of the central axis 621. The first crank rocker mechanism 66 and the second crank rocker mechanism 67 are respectively connected to the two ends of the driving rod 622. The output power of the first ankle joint motor 63 and the second ankle joint motor 64 is transmitted to the driving rod 622 through their respective crank mechanisms, driving the driving rod 622 to rotate around the central axis 621, thereby realizing two degrees of freedom of the ankle joint. This design integrates the output power of the two motors into the same driving rod 622, realizes coaxial output, thereby improving the driving efficiency, reducing the space occupied by the ankle joint, and improving the compactness of the leg structure.

[0036] It is worth noting that the driving rod 622 is arranged at the rear part of the foot 62 instead of the front part, mainly based on the following considerations:

[0037] 1) Larger swing space: The rear drive rod can provide a larger swing space for the front end of the foot, especially when walking on rough ground, which can better adapt to changes in terrain and avoid collision between the front end of the foot and the ground.

[0038] 2) Better at imitating biological motion: Many animals, especially mammals, have their leg drive structures located at the rear, such as the Achilles tendon connecting the calf muscles to drive the foot. The design of the rear drive rod is closer to this biological structure, which can better imitate the movement of organisms and achieve a more natural and smooth gait.

[0039] 3) Protect the drive mechanism: Placing the drive rod at the rear can better protect the drive mechanism from external impact and contamination. When the robot is walking, the front end of the foot is more likely to collide with obstacles on the ground. Placing the drive rod at the rear can reduce the risk of damage to the drive mechanism.

[0040] 4) Shifting the center of gravity backwards to improve stability: The rear drive rod can shift the center of gravity of the foot backwards, which is beneficial to improving the overall stability of the robot, especially when performing some dynamic movements such as running or jumping, so that the robot can maintain balance better.

[0041] like Figure 3 As shown, the first crank rocker mechanism 66 includes a first rotating disk 661 fixed on the output shaft of the first ankle joint motor 63, and a first eccentric column 662 is provided on the first rotating disk 661. A relay rotating disk 663 is rotatably connected to the calf support 61, and a second eccentric column 664 and a third eccentric column 665 are provided on the relay rotating disk 663. The first eccentric column 662 and the second eccentric column 664 are connected by a connecting rod 666, and the third eccentric column 665 and one end of the driving rod 622 are connected by a first universal connecting rod 667.

[0042] It is worth noting that the present invention uses the relay turntable 663 as the node for force transmission, rather than directly using a long rod to directly connect the first turntable 661 and the driving rod 622. This design is based on the following reasons:

[0043] 1) Reduce the motion error caused by the deformation of the long rod: If a long rod is directly used to connect the first turntable 661 and the driving rod 622, the rod is long and prone to bending or twisting deformation during the force process. This deformation will directly affect the transmission accuracy of the torque, causing errors in the foot movement, and further affecting the stability and accuracy of the robot's gait. By using the relay turntable 663, the long rod can be decomposed into two shorter rods, effectively reducing the deformation of the rod, thereby improving the accuracy of torque transmission and the accuracy of foot movement.

[0044] 2) Reduce the inertial effect of long rods: Longer rods mean greater mass and moment of inertia. During the rapid movement of the robot, the inertia of the long rod will produce a large inertial force, affecting the dynamic performance and control accuracy of the robot. The use of relay turntable 663 can effectively reduce the inertia of moving parts and improve the response speed and movement flexibility of the robot.

[0045] 3) Avoid spatial interference caused by long rods: In the limited leg space, overly long rods are prone to spatial interference with other components, limiting the robot's range of motion and even causing the mechanism to get stuck. The added relay turntable 663 shortens the rod length, effectively avoids the spatial interference problem, and improves the compactness of the mechanism design.

[0046] 4) Improve the adjustability of the mechanism: The added relay turntable 663 provides more possibilities for adjustment and optimization of the mechanism. By adjusting the position and size of the relay turntable, the movement trajectory and torque output of the foot can be more finely controlled, thereby better adapting to different terrains and sports requirements.

[0047] Further, the first universal connecting rod 667 includes a first rod body 6671, and the two ends of the first rod body 6671 are connected to the first rod end joint bearings 6672 through threads. Here, the joint bearings 6672 are universal joints or ball bearings, which can flexibly transmit rotational motion. Since the first rod end joint bearings 6672 at both ends of the first rod body 6671 are connected to the first rod body 6671 through threads, the distance between the two first rod end joint bearings 6672 can be adjusted as needed.

[0048] Similarly, the second crank rocker mechanism 67 includes a second turntable 671 fixed on the output shaft of the second ankle joint motor 64, and a fourth eccentric column 672 is provided on the second turntable 671. The fourth eccentric column 672 and the other end of the driving rod 622 are connected by a second universal connecting rod 673. Further, the second universal connecting rod 673 includes a second rod body 6731, and the two ends of the second rod body 6731 are connected to the second rod end joint bearing 6732 by threads. The second rod end joint bearing 6732 is usually a universal joint or a ball bearing, and the distance between the two can also be adjusted.

[0049] The design of this crank mechanism can optimize the torque transmission path and efficiently transmit the driving force of the motor to the joint, thereby reducing energy loss and improving driving efficiency. At the same time, due to the coaxial output of the first ankle motor 63 and the second ankle motor 64, the degree of motion decoupling of the two degrees of freedom is high, which is convenient for kinematic and dynamic modeling, reduces the complexity of the control algorithm, and helps to improve the real-time performance and stability of the robot control system. In addition, the crank mechanism is easy to standardize and modularize, making the design and assembly of the robot joint more flexible and convenient for later maintenance and upgrading.

[0050] Furthermore, the first ankle joint motor 63 and the second ankle joint motor 64 are arranged up and down to reduce the space occupied by the ankle joint, further improve the compactness of the leg structure, and make the two degrees of freedom of motion decoupling degree higher, which is convenient for control. Specifically, when the first ankle joint motor 63 and the second ankle joint motor 64 are arranged up and down, the output ends of the two motors are unified into a coaxial position (central axis 621) by using two crank mechanisms, which can reduce the space occupied by the joint, make the robot leg design more compact, and improve the overall aesthetics and flexibility.

[0051] Furthermore, in order to further optimize torque transmission, simplify structure and improve performance, the present invention also adopts a coaxial design. Specifically, the first eccentric column 662 and the second eccentric column 664 have the same rotation radius; the fourth eccentric column 672 and the third eccentric column 665 have the same rotation axis and the same rotation radius. Of course, the relay turntable 663 and the second turntable 671 are also coaxial, and the first universal connecting rod 667 and the second universal connecting rod 673 are also the same length and symmetrical. This coaxial design brings the following advantages:

[0052] 1) Greatly simplify the mechanical model: By placing the rotation centers of multiple key components on the same axis, the mechanical model of the mechanism is greatly simplified. This makes the design of motion analysis and control algorithms more convenient, reduces computational complexity, and improves the real-time performance and efficiency of the control system.

[0053] 2) Significantly reduce space occupation and improve structural compactness: The coaxial design minimizes the radial size of the mechanism, thereby significantly reducing space occupation and making the entire crank mechanism more compact.

[0054] Further, the foot 62 is an arched structure to enhance the adaptability of the foot to the ground and provide a certain buffering effect. Specifically, the foot 62 includes a foot plate and a dorsum of the foot, and a hole is provided between the foot plate and the dorsum of the foot, and the hole is usually arched (similar to a fan ring).

[0055] The foot 62 is designed as an arch structure, which can better disperse pressure through its curved structure, increase the contact area with the ground, reduce the pressure concentration of the sole of the foot on the ground, and thus improve the standing stability of the robot on various terrains. The arc structure of the arched foot has certain elastic properties, which can play a buffering role when walking or jumping, reduce the damage to the robot structure caused by the impact force, and improve the stability of the gait, which helps to better adapt to uneven terrain; the arch structure helps to imitate the function of the human arch, reduce energy loss by storing and releasing energy, and improve the efficiency of walking and running, especially in dynamic movements.

[0056] Furthermore, the bottom of the foot 62 is detachably connected (usually connected by sleeve connection, clamping connection, etc.) with a flexible sole 623, so that the sole can be replaced according to different ground environments, thereby improving the robot's adaptability to different terrains. Specifically, by adopting a detachable and replaceable sole structure design, flexible sole modules of different materials, hardness, thickness or shape can be quickly replaced according to the terrain type to optimize the robot's motion performance and stability in different environments. For example, a soft pad with a higher friction coefficient is used on a smooth ground, and a thicker soft pad is used on a rugged ground to enhance the cushioning effect. The sole structure is easy to wear, and the detachable design facilitates the replacement of the sole module after damage or aging without replacing the entire foot assembly, thereby extending the overall service life of the robot and reducing maintenance costs; the flexible sole can absorb and release energy through the elastic properties of the material, helping the robot to reduce energy loss when walking, running or jumping, and improve movement efficiency; the flexible sole has excellent cushioning capacity, which can absorb the impact of the robot's contact with the ground, reduce damage to the robot's joints and body, and improve the smoothness of movement.

Claims

1. A bipedal robot leg structure, characterized in that: The invention comprises a central base (1), the central base (1) is connected to a hip joint flexion and extension motor (2), the output shaft of the hip joint flexion and extension motor (2) is provided with a hip joint abduction motor (3), and the central axes of the two are perpendicular to each other, the output shaft of the hip joint abduction motor (3) is provided with a hip joint internal and external rotation motor (4), and the central axes of the two are perpendicular to each other, the output shaft of the hip joint internal and external rotation motor (4) is provided with a knee joint motor (5), and the central axes of the two are perpendicular to each other; the output shaft of the knee joint motor (5) is provided with a calf group Part (6), the calf component (6) comprises a calf support (61) and a foot (62), the calf support (61) is provided with a first ankle joint motor (63) and a second ankle joint motor (64), a universal joint (65) movably connecting the foot (62) and the lower part of the calf support (61) is provided, a first crank rocker mechanism (66) is provided between the first ankle joint motor (63) and the foot (62), and a second crank rocker mechanism (67) is provided between the second ankle joint motor (64) and the foot (62); A drive rod (622) is placed horizontally at the rear of the foot (62), the first crank rocker mechanism (66) is arranged between the first ankle joint motor (63) and one end of the drive rod (622), and the second crank rocker mechanism (67) is arranged between the second ankle joint motor (64) and the other end of the drive rod (622); the output power of the first ankle joint motor (63) and the second ankle joint motor (64) is transmitted to the coaxial output drive rod (622) through the two sets of crank rocker mechanisms, so as to realize the two-degree-of-freedom movement of the ankle joint; The first crank rocker mechanism (66) includes a first turntable (661) arranged on the output shaft of the first ankle joint motor (63), a first eccentric column (662) is arranged on the first turntable (661), a relay turntable (663) is rotatably connected to the calf support (61), a second eccentric column (664) and a third eccentric column (665) arranged opposite to each other are arranged on the relay turntable (663), a connecting rod (666) is arranged between the second eccentric column (664) and the first eccentric column (662), and a first universal connecting rod (667) is arranged between the third eccentric column (665) and one end of the driving rod (622).

2. A bipedal robot leg structure according to claim 1, characterized in that: The second crank rocker mechanism (67) comprises a second turntable (671) arranged on the output shaft of the second ankle joint motor (64), a fourth eccentric column (672) being arranged on the second turntable (671), and a second universal connecting rod (673) being arranged between the other end of the fourth eccentric column (672) and the driving rod (622).

3. The biped robot leg structure according to claim 1, characterized in that: The first eccentric column (662) and the second eccentric column (664) have the same rotation radius.

4. A bipedal robot leg structure according to claim 2, characterized in that: The fourth eccentric column (672) and the third eccentric column (665) have the same rotation axis and the same rotation radius.

5. The biped robot leg structure according to claim 1, characterized in that: The first ankle joint motor (63) and the second ankle joint motor (64) are arranged vertically.

6. The biped robot leg structure according to claim 1, characterized in that: A central axis (621) is provided at the rear of the foot (62), and the driving rod (622) is provided at the end of the central axis (621).

7. The biped robot leg structure according to claim 1, characterized in that: The first universal connecting rod (667) comprises a first rod body (6671), and both ends of the first rod body (6671) are connected to first rod end joint bearings (6672) via threads.

8. The biped robot leg structure according to claim 2, characterized in that: The second universal connecting rod (673) comprises a second rod body (6731), and both ends of the second rod body (6731) are connected to second rod end joint bearings (6732) via threads.

9. The biped robot leg structure according to claim 1, characterized in that: The foot (62) is an arch-shaped structure.

10. The biped robot leg structure according to claim 1, characterized in that: The bottom of the foot (62) is detachably connected to a flexible sole (623).

Images