Humanoid robot leg joint

Abstract

This utility model relates to robotics, specifically to software-controlled manipulators that enable spatial movement of mechanical elements. The leg assembly of a humanoid robot comprises a femur body, a tibia body, and a knee joint consisting of a rocker arm connected to a linear actuator and a tie rod. The tie rod is pivotally mounted on the tibia body. The rocker arm contains axes for three hinge joints: the first joint connects the rocker arm to the extending element of the linear actuator, the second joint connects the rocker arm to the femur body, and the third hinge joint connects the rocker arm to the tibia body. The tie rod is pivotally attached to the femur and is formed by two flat angular elements attached to a single axis and arranged parallel in space. Each angular element has a rounded apex, an obtuse angle between its ends, and an arcuate lateral surface.The shin body is plate-shaped, with flat recesses on the front surfaces at its upper end. The end surfaces of the recesses form stops, and the linkage is mounted on the shin body, allowing its corner elements to engage with the stops on the shin body. The hinge joints of the rocker arm and linkage with the femur and shin bodies are equipped with spherical bearings. This ensures optimized kinematics of the links while reducing the weight and dimensions of the robotic leg assembly. 10 fig.

Description

[0001] This utility model relates to robotics, specifically to software-controlled manipulators that enable spatial movement of mechanical elements. It is applicable to the knee joint of an anthropomorphic robot to transmit linear drive motion to controlled links with movable joints. It can also be used in the design of a robot that imitates human movements, to perform movements of the robot's leg parts, and to propel the robot through space.

[0002] A robot knee joint assembly is known from international patent application WO 2024073135, B62D57 / 032, 2024. The knee joint assembly includes a first connecting element, the first end of which is mechanically connected to the upper leg of the robot and can rotate about a first hinge relative to the upper leg. The knee assembly also includes a second connecting element, the first end of which is mechanically connected to the lower leg of the robot. The lower leg is mechanically connected to the upper leg and can rotate about a second hinge relative to the upper leg. A linear actuator is mechanically connected to the second end of the first link and the second end of the second link. When actuated, the linear actuator causes the first link to rotate about the first hinge relative to the upper leg of the robot, and the lower leg to rotate about the second hinge relative to the upper leg.The knee joint design converts the linear motion generated by the linear actuator into rotational motion of the robot's lower leg. The robot's lower leg can rotate up to 175 degrees. A disadvantage is the design's complexity, which includes a large number of mechanical links, and the large size of the assembly.

[0003] A bionic robotic leg mechanism is known under Chinese Patent for Invention CN 119568306, B62D57 / 032, 2025. The cross-shaped four-link mechanism consists of a femoral rod, a shaft, a linear actuator, a rocker arm, and a triangular connecting rod. The linear actuator causes the triangular connecting rod to move around the femoral rod, driving the shaft and rocker arm, which rotate around a variable pivot point in a plane. The femoral rod is fixed to the platform using a hip swivel joint, providing rotational movement of the hip joint. The fixed end of the linear actuator is mounted on the femoral rod, and the output end is fixed to a V-shaped block. The V-shaped block is also connected to the femoral rod and calf rod via an axle. To ensure force balance, connecting rods are installed on both sides. One end of the connecting rod is connected to the femoral crank, and the other to the calf crank.The disadvantage is the use of cranks, which increase the size and weight of the leg structure.

[0004] The leg design according to Chinese Patent for Invention CN 119459924, B62D57 / 032, 2025, was selected as the closest analogue to the claimed technical solution. The lower leg structure consists of a femur, tibia, and foot, which are sequentially connected from top to bottom. The femur, knee joint rocker, femoral tibia thrust, and tibia body form a four-link mechanism. The femur, knee joint drive motor, and knee joint rocker form a crank mechanism. The femoral assembly includes a femoral housing, a motor connecting shaft, a knee joint drive motor, a knee joint rocker, a gastrocnemius muscle thrust, a tibia connecting shaft, and a rocker connecting shaft. The femoral housing is a frame structure consisting of first and second femoral lateral plates.The first and second femur side plates are respectively connected to the engine coupling shaft, the rocker arm coupling shaft, and the tibia coupling shaft. The lower end of the femur body is movably connected to the calf joint via the calf muscle coupling shaft. The knee joint drive motor is located between the first and second femur side plates and is located between the engine coupling shaft and the rocker arm coupling shaft. The knee joint drive motor has a fixed end and a telescopic end. The fixed end of the knee joint drive motor is movably connected to the upper end of the femur body via the engine coupling shaft, and the telescopic end of the knee joint drive motor is connected to the knee joint rocker arm, which can rotate around the rocker arm coupling shaft.The knee joint rocker arm extends through the anterior portion of the tibia connecting shaft and is movably connected to the tibia via a rod, allowing relative rotation of the femur and tibia around the connecting shaft. The knee joint rocker arm is C-shaped with three connecting ends. The telescopic end of the knee joint drive motor is connected to the first connecting end of the rocker arm, and the first connecting end of the knee joint rocker arm moves under the action of the rod of the knee joint drive motor. The second connecting end of the knee joint rocker arm is connected to the femur body via the rocker arm connecting shaft, and the knee joint rocker arm can rotate around the connecting shaft. The joint rocker arm extends in front of the tibia connecting shaft. The third connecting end of the rocker arm is connected to the femur body and connected to the rod via a rotating shaft. The lower end of the rod is movably connected to the tibia assembly.The connecting shaft of the traction rod is located below the connecting shaft of the lower leg and is movably connected to the lower end of the rod. A disadvantage is the large weight and dimensions of the structure due to the use of a massive connecting section of the lower leg with the knee joint. The upper connecting section of the lower leg, which interacts with the knee joint rod, is designed as a box-shaped structure, with a shaft located between its sides to transmit movement from the knee joint to the lower leg. The large dimensions of the knee joint and lower leg joint hinder the creation of a compact robotic leg, do not allow for optimal load distribution among the components, and require greater force to move the knee joint.

[0005] The technical objective of the claimed utility model is to expand the arsenal of means related to the knee joints of humanoid robots.

[0006] The technical result is the achievement of the stated purpose by creating a robot leg unit with reduced weight and dimensions.

[0007] The technical result is achieved due to the fact that in the leg unit of a humanoid robot, containing a thigh body, a shin body, a knee joint, which consists of a rocker arm connected to a linear drive, and a thrust, the thrust is pivotally mounted on the shin body, the rocker arm contains axes for three hinge joints, the first connection is the connection of the rocker arm and the rod of the linear drive, the second connection is the connection of the rocker arm with the thigh body, according to the utility model, the thrust is pivotally fixed on the thigh and is made in the form of two flat angular elements that are fixed on one axis and placed in space parallel to each other, each angular element is made with a rounded top, an obtuse angle between its ends and an arcuate lateral surface, the shin body is made of a plate shape, with flat recesses on the front sides at its upper end, the end surfaces of the recesses form stops,the rod is mounted on the shin body with the possibility of interaction of its angular elements with the stops of the shin body, the rocker arm is connected to the shin body by a third hinge joint, the hinge joints of the rocker arm and rod with the femur and shin bodies are equipped with hinge bearings.

[0008] The technical result is achieved by implementing the shin body as a single flat plate-shaped structure, with reduced dimensions and weight compared to the closest analog, which has a box-shaped shin. Recesses on the front sides of the shin body provide stops for interaction with the rod. The inclusion of recesses on the shin body reduces the overall weight and dimensions of the structure. The rod is designed as two flat, parallel angular elements mounted on a single axis, with a rounded apex between the ends and an arcuate lateral surface. These elements interact with the shin stop, allowing the rods to rotate and transmit force from the rod to the shin stop, causing it to rotate. This design of the rods and stops in the assembly eliminates the need for complex mechanisms for transmitting motion to the shin, as well as the need for a box-shaped structure with an internal axis, as in the closest analog.All this significantly simplifies and reduces the design of the unit, reducing its dimensions and weight. The third hinge joint connects the rocker arm directly to the shank housing, which also reduces the unit's dimensions compared to its closest analogue, which still has a long rod between the rocker arm and the shank housing. Furthermore, the reduction in the length of the hinge axis itself, due to its placement in a hole in the flat part of the shank housing, also reduces the width of the unit and its weight. The use of bearings in the hinge joints between the rocker arm and the shank housing, the rocker arm and the shank housing, the rod and the shank housing, and the rod and the shank housing improves their sliding characteristics and load-bearing capacity, reduces the load on the hinge pins, and, consequently, without compromising reliability, reduces the weight and dimensions of all components of these joints.

[0009] Fig. 1 shows a general view of the leg unit of a humanoid robot.

[0010] Fig. 2 shows the knee joint rocker arm of the leg unit of a humanoid robot.

[0011] Fig. 3 shows the linear actuator of the leg unit of the humanoid robot.

[0012] Fig. 4 shows a fragment of the thigh body of the leg unit of a humanoid robot.

[0013] Fig. 5 shows the traction unit of the leg of a humanoid robot.

[0014] Fig. 6 shows a fragment of the shin body of the leg unit of a humanoid robot.

[0015] Fig. 7 shows a sectional view of the leg assembly of a humanoid robot.

[0016] Fig. 8-10 shows a sectional view of the leg assembly of the humanoid robot in various working positions.

[0017] The leg unit of the humanoid robot comprises a thigh body 1, a shin body 2, a rocker arm 3 connected to a linear actuator 4, and a rod 5. The thigh body 1 has a frame structure with plate-shaped sides. The shin body 2 is made as a single plate-shaped part. The rocker arm 3 is made as a double-arm lever consisting of two parts 6 with axes 7, 8, 9 installed in them. The axis 7 is installed in the sleeve 10 of the rod collar of the linear actuator 4. Both parts of the axis 9 of the rocker arm 3 are mounted in the swivel bearings 11 in the sides of the thigh body 1. The axis 8 of the rocker arm 3 is installed in the swivel bearing 12 of the shin body 2. The shin body 2 is made as a flattened vertical structure with flat recesses in the upper part. The lower end surfaces of the recesses form stops 13 on the front sides of the shin body 2. The rod 5 is made in the form of two parallel plate-shaped angular elements 14, fixed on the axis 15.Each angular element 14 is roundly curved at its apex to form an obtuse angle between the ends. The lateral surface of each element has a curved arcuate section 16. The upper part of the rod 5 is mounted on the axis 15 of the lateral sides of the femur body 1 by means of articulated bearings 19. In the upper part of the shin body 2, articulated bearings 18 interact with the axis 17, to which the lower ends of the angular elements 14 of the rod 5 are secured. The lower ends of these elements are mounted so as to be able to interact with the stops 13 of the shin body 2.

[0018] The leg unit of the humanoid robot works as follows.

[0019] When it is necessary to move the leg unit of the humanoid robot, a signal is sent from the control system to the linear actuator 4. The force created by the linear actuator 4 is transmitted through the axis 7 to the rocker arm 3. As the rod of the linear actuator 4 extends, the rocker arm 3, with the help of the axis 9 installed in the bearings 11, rotates relative to the body of the femur 1. The rocker arm 3 rotates and displaces the body of the shin 2, transmitting a force to it through the axis 8 in the bearing 12 of the body of the shin 2. In this case, the force is also transmitted to the thrust 5. The lower ends of the angular elements 14 of the thrust 5, rotating around the axis 17, turn and act with the curvilinear side sections 16 on the surfaces of the stops 13, causing the body of the shin 2 to perform a rotational motion. When moving the body of the lower leg 2, a wide range of motion is achieved; it is possible to rotate the body of the lower leg 2 relative to the body of the thigh 1 by 15° towards the toe and by 135° towards the heel.This rotation closely mimics the biomechanics of the human knee. The design of the unit ensures optimized kinematics of the links, enabling efficient force transmission while minimizing the overall dimensions of the robot's shell. All unit axes are mounted on set screws, allowing for quick disassembly and repair. All unit fasteners are located on the front sides, further enabling quick disassembly. Linear actuator 4 extends the piston rod with constant force throughout its entire travel range. This movement is transmitted to the tibia without significant loss. All elements move uniformly, smoothly transferring the load to the unit. Even load distribution and reduced component weight reduce wear and increase the unit's durability.

[0020] Thus, the utility model makes it possible to expand the arsenal of means related to the knee joints of humanoid robots by creating a robot leg joint with reduced weight and dimensions.

Claims

A leg unit of a humanoid robot comprising a thigh body, a shin body, a knee joint which consists of a rocker arm connected to a linear drive and a traction rod, the traction rod is pivotally mounted on the shin body, the rocker arm contains axes for three hinge joints, the first joint is a joint between the rocker arm and a retractable element of the linear drive, the second joint is a joint between the rocker arm and the thigh body, characterized in that the traction rod is pivotally fixed on the thigh and is made in the form of two flat angular elements which are fixed on the same axis and placed in space parallel to each other, each angular element is made with a rounded top, an obtuse angle between its ends and an arcuate lateral surface, the shin body is made of a plate shape with flat recesses on the front sides at its upper end, the end surfaces of the recesses form stops, the traction rod is mounted on the shin body with the possibility of interaction of its angular elements with the stops of the shin body,The third hinge joint connects the rocker arm to the shin body; the hinge joints of the rocker arm and the rod with the femur body and the shin body are equipped with swivel bearings.

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