A humanoid robot hip module based on linkage differential and inverted Y-shaped configuration

Abstract

This invention discloses a humanoid robot hip and waist module based on a linkage differential and inverted Y-shaped configuration, including a yaw and differential attitude control assembly. This assembly includes a positioning frame one, a waist drive component mounted on the positioning frame one along the Z-axis, a right differential drive component and a left differential drive component fixed along the Y-axis, and a transmission component that works in conjunction with these components to achieve pitch motion of the robot's waist. The inverted Y-shaped hip joint load-bearing assembly includes a positioning frame two and a left hip drive component and a right hip drive component mounted in an inverted Y-shape on the positioning frame two. This humanoid robot hip and waist module innovatively introduces a parallel differential mechanism composed of dual direct-drive motors, rigid linkages, and universal joints, completely eliminating the backlash of traditional gear differentials and achieving clear decoupling and precise control of pitch and yaw degrees of freedom. Simultaneously, the inverted Y-shaped symmetrical arrangement of the dual hip drives constructs a mechanical transmission structure with high load-bearing stiffness and excellent bending moment resistance.

Description

Technical Field

[0001] This invention relates to the field of biomimetic robot and electromechanical transmission control technology, and in particular to a humanoid robot waist and hip module based on linkage differential and inverted Y-shaped configuration. Background Technology

[0002] In recent years, humanoid robots, as important physical carriers of embodied intelligence, have shown broad application prospects in fields such as industrial manufacturing, special operations, and disaster relief. In the overall topology of a humanoid robot, the hip joint module is the core hub connecting the robot's torso and lower limbs. It not only needs to provide flexible multi-degree-of-freedom movements (such as waist yaw, hip pitch, and lateral movement) to adapt to complex terrain and operational requirements, but also needs to withstand dynamic impact loads beyond the weight of the upper body when the robot performs movements with strong dynamic characteristics (such as fast walking, running, jumping, and squatting). Therefore, the transmission accuracy, structural stiffness, moment of inertia, and mechanical distribution characteristics of the hip joint module directly determine the control stability and explosive power of the humanoid robot's lower limb movements.

[0003] Currently, the existing technologies for implementing the hip joint of humanoid robots mainly include the following methods, but all of them have significant limitations in practical high-dynamic and high-load application scenarios:

[0004] 1. Traditional single-axis motor series connection scheme: Most existing bipedal or humanoid robots generally use a structure of multiple single-axis servo motors connected end to end (i.e., "cantilever beam") to achieve multi-degree-of-freedom movement in the waist and hip joints.

[0005] Existing drawbacks: The distal mass of this series structure is extremely large, meaning the proximal (upper) motor must constantly bear the weight of the distal (lower) motor. This causes the swing inertia of the robot's legs to increase exponentially, severely restricting the high-frequency dynamic response of the lower limbs. At the same time, the series structure is prone to deformation and stress concentration when subjected to external dynamic impacts, and the return clearance of each series joint will cause linear error accumulation, resulting in low foot control accuracy.

[0006] 2. Differential / parallel scheme based on bevel gear transmission: In order to solve the problem of concentrated inertia distribution caused by series mechanism, some existing technologies use a differential mechanism with dual motors and bevel gear sets to realize the pitch and lateral swing of the hip.

[0007] Existing drawbacks: Gear meshing transmissions inevitably have backlash. Under frequent forward and reverse rotation conditions caused by robot gait switching, the gear teeth are prone to wear, leading to further widening of the backlash and a significant decrease in control accuracy over time. In addition, gearboxes that withstand high torque are bulky, heavy, and require complex lubrication and sealing designs, making it difficult to meet the demands of modern humanoid robots for lightweight design and high torque density.

[0008] 3. Parallel push rod solution based on linear electric cylinders: Some heavy-duty robots adopt a parallel linear electric cylinder mechanism similar to the Stewart platform. The hip flange is supported by the extension and retraction of multiple push rods to achieve multi-posture adjustment.

[0009] Existing drawbacks: The mechanical extension and retraction of the linear actuators severely limits the joint's maximum workspace, preventing the robot from performing large-angle squats, long strides, and other similar movements. Furthermore, the forward and inverse kinematics calculations for this configuration are complex, making it prone to kinematic singularities under specific poses, significantly increasing the difficulty of underlying motion control. Additionally, this parallel platform requires a large number of linear electric cylinders for driving, resulting in poor economic efficiency.

[0010] 4. Traditional vertical parallel lower limb arrangement configuration: Most existing humanoid robots use a parallel arrangement perpendicular to the ground for their leg and hip drive units.

[0011] Existing drawbacks: When landing on one leg or after a running jump, the ground reaction force is transmitted vertically upwards, creating a large lateral bending moment in the hip and lumbar spine. This lower limb arrangement requires a main frame with a large bending section modulus to reduce structural stress, which is not conducive to lightweight structural design.

[0012] In summary, existing hip joint mechanisms struggle to simultaneously achieve low end-effector inertia, zero / low backlash, large range of motion, and high structural rigidity. Therefore, a novel hip joint module configuration is urgently needed to effectively address these challenges and meet the engineering requirements of highly dynamic humanoid robots. Summary of the Invention

[0013] To address the aforementioned technical problems, this invention proposes a humanoid robot hip module based on a linkage differential and an inverted Y-shaped configuration. This humanoid robot hip module innovatively introduces a parallel differential mechanism composed of dual direct-drive motors, rigid linkages, and universal joints, completely eliminating the backlash of traditional gear differentials and achieving clear decoupling and precise control of pitch and yaw degrees of freedom. Simultaneously, through the inverted Y-shaped symmetrical arrangement of the dual hip drives, a mechanical transmission structure with high load-bearing stiffness and excellent bending moment resistance is constructed, perfectly balancing lightweight design with high dynamic and heavy-load motion requirements, fundamentally improving the stability and explosive power of the humanoid robot's lower limb movements.

[0014] A humanoid robot hip module based on linkage differential and inverted Y-shaped configuration, including

[0015] A yaw and differential attitude control assembly includes a positioning frame. A waist drive component is fixed at the top center of the positioning frame along the Z-axis. The waist drive component is used to realize the robot's steering. A right differential drive component and a left differential drive component are fixed on both sides of the positioning frame along the Y-axis and are symmetrically arranged. The right differential drive component and the left differential drive component are connected to a transmission assembly to realize the pitch movement of the robot's waist.

[0016] An inverted Y-shaped hip joint bearing assembly includes a positioning frame two, on which a left hip drive component and a right hip drive component are symmetrically fixed, and the left hip drive component and the right hip drive component are arranged in an inverted Y shape.

[0017] As a preferred embodiment of the above technical solution, the transmission assembly is arranged in two parallel sets, including a connecting rod and a fisheye joint rotatably connected to one end of the connecting rod. The other end of the connecting rod is hinged to a joint self-aligning bearing fixed to the top of the second positioning frame. The other ends of the two sets of fisheye joints are respectively connected to the output shafts of the right differential drive and the left differential drive, which are arranged inward.

[0018] As a preferred embodiment of the above technical solution, a universal joint is fixed to the top of the positioning frame two. The universal joint is coaxially arranged with the waist drive component, and one of the rotation axes of the universal joint is parallel to the Y-axis direction where the right differential drive component and the left differential drive component are located.

[0019] As a preferred embodiment of the above technical solution, the universal joint and two rotary joints on the rotation axis that are parallel to the Y-axis direction of the right differential drive and the left differential drive are fixed to the positioning frame.

[0020] As a preferred embodiment of the above technical solution, the waist drive component, the right differential drive component, the left differential drive component, the left hip drive component, and the right hip drive component all adopt an integrated joint of motor and reducer.

[0021] As a preferred embodiment of the above technical solution, both the first positioning frame and the second positioning frame adopt a topological hollowing-out weight reduction design.

[0022] As a preferred embodiment of the above technical solution, the positioning frame one and the positioning frame two can be prepared by any one of the following methods: CNC machining of aerospace aluminum alloy / titanium alloy, integral molding of carbon fiber reinforced composite material, and internal dot matrix filling molding of metal 3D printing.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. Extremely high transmission precision and fundamentally eliminates backlash. This solution uses a parallel differential mechanism composed of rigid connecting rods and a cross shaft to replace the traditional bevel gear differential, completely eliminating the mechanical backlash caused by gear meshing and wear errors under long-term high torque operation, and significantly improving the absolute precision and high-frequency response speed of waist posture control.

[0025] 2. The structural load-bearing stiffness has increased dramatically, and the resistance to lateral impact has been significantly enhanced. Thanks to the innovative inverted Y-shaped hip space arrangement, when the robot performs high-dynamic movements such as running, jumping, landing, or single-leg support, the huge instantaneous reaction force and lateral bending moment from the ground can be efficiently and evenly transmitted and resolved to the high-stiffness central main frame along the inclined motor axis, perfectly avoiding the stress concentration and yielding deformation that are prone to occur at the root of traditional vertical parallel configurations.

[0026] 3. Significantly reduced rotational inertia at the lower limb end. This design highly converges and concentrates the heavy drive motors responsible for multi-degree-of-freedom movements of the waist and hips in the pelvic trunk base area, greatly reducing the basic weight of the leg extension end, thereby significantly reducing the swing inertia of the lower limbs. This lays the underlying hardware foundation for the robot to achieve agile gait switching and high-explosive movements.

[0027] 4. Maximizing torque output efficiency and achieving ultimate lightweight design. When performing waist-thrusting movements that require the most resistance to gravity, the dual differential motors achieve physical torque superposition, doubling the load-bearing efficiency. At the same time, each mounting base and support side plate adopts a topological hollow design based on the force flow direction, which significantly reduces the system's ineffective dead weight while maintaining extremely high bending section modulus, thus significantly improving the robot's payload ratio and overall energy efficiency. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the present invention.

[0029] Figure 2 This is a longitudinal sectional view of the present invention.

[0030] The attached diagram is labeled as follows: 1-Positioning frame one, 2-Waist drive component, 3-Right differential drive component, 4-Left differential drive component, 5-Transmission assembly, 501-Connecting rod, 502-Fisheye joint, 503-Articulated self-aligning bearing, 6-Positioning frame two, 7-Left hip drive component, 8-Right hip drive component, 9-Universal joint. Detailed Implementation

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0032] like Figure 1 , Figure 2 The aforementioned humanoid robot hip module based on linkage differential and inverted Y-shaped configuration includes:

[0033] A yaw and differential attitude control assembly includes a positioning frame 1. A waist drive component 2 is fixed at the top center of the positioning frame 1 along the Z-axis. The waist drive component 2 is used to realize the robot's steering. A right differential drive component 3 and a left differential drive component 4 are fixed on both sides of the positioning frame 1 along the Y-axis and are symmetrically arranged. The right differential drive component 3 and the left differential drive component 4 are connected to a transmission assembly 5 to realize the pitch movement of the robot's waist.

[0034] An inverted Y-shaped hip joint bearing assembly includes a positioning frame 6, on which a left hip drive component 7 and a right hip drive component 8 are symmetrically fixed, and the left hip drive component 7 and the right hip drive component 8 are arranged in an inverted Y shape.

[0035] In this embodiment, the transmission assembly 5 is arranged in parallel with two sets, including a connecting rod 501 and a fisheye connector 502 rotatably connected to one end of the connecting rod 501. The other end of the connecting rod 501 is hinged to a joint self-aligning bearing 503 fixed to the top of the positioning frame 6. The other ends of the two sets of fisheye connectors 502 are respectively connected to the output shafts of the right differential drive 3 and the left differential drive 4, which are arranged inward.

[0036] In this embodiment, a universal joint 9 is fixed to the top of the positioning frame 2 6. The universal joint 9 is coaxially arranged with the waist drive member 2. One of the rotation axes of the universal joint 9 is parallel to the Y-axis direction where the right differential drive member 3 and the left differential drive member 4 are located.

[0037] In this embodiment, the universal joint 9 and the two rotary joints on the rotation axis that are parallel to the Y-axis direction of the right differential drive 3 and the left differential drive 4 are fixed to the positioning frame 1.

[0038] In this embodiment, the waist drive component 2, the right differential drive component 3, the left differential drive component 4, the left hip drive component 7, and the right hip drive component 8 all adopt an integrated joint of motor and reducer.

[0039] In this embodiment, both the positioning frame 1 and the positioning frame 6 adopt a topological hollowing-out weight reduction design.

[0040] In this embodiment, the positioning frame 1 and the positioning frame 6 can be prepared by any of the following methods: CNC machining of aerospace aluminum alloy / titanium alloy, integral molding of carbon fiber reinforced composite material, or internal dot matrix filling molding by metal 3D printing.

[0041] The working principle of this embodiment is as follows.

[0042] Torso steering (yaw around the Z-axis): Independently driven by the waist drive unit 2. When the waist drive unit 2 rotates clockwise or counterclockwise, it directly drives the torso structure connected above to rotate around the vertical Z-axis, realizing the robot's left and right turning movements.

[0043] Pitch motion (around the Y-axis): When it is necessary to control the upper body to tilt forward or backward, the right differential drive 3 and the left differential drive 4 are controlled to rotate in the same direction with the same angular velocity. At this time, the two sets of connecting rods 501 will perform identical spatial movements (including translation of the center of mass and rotation around the center of mass), transmitting the motion from the stationary base platform to the upper body mechanism through the fisheye joints 502 at both ends. The two sets of connecting rods 501 work together to symmetrically pull or push the upper body frame to overcome the overturning moment caused by the gravity offset when the upper body module tilts forward or backward. The entire process is directly transmitted by rigid connecting rods 501, completely eliminating the mechanical backlash caused by the differential of traditional bevel gear sets, ensuring the absolute accuracy of the pitch attitude.

[0044] Lateral swaying motion of the waist (around the X-axis, Roll): When it is necessary to control the lateral swaying of the pelvic region, the right differential drive 3 and the left differential drive 4 are controlled to rotate in opposite directions at the same angular velocity (forming a differential). At this time, the two sets of linkages 501 perform spatial dual motion relative to the upper body coordinate system, facing opposite directions. The lower ends of the two linkages 501 are rigidly fixed to the upper platform of the rigid hip joint through the fisheye joint 502, and the upper ends are connected to the upper body through the fisheye joint 502. The differential action guides the lateral swaying motion. The two sets of linkages 501 pull and push, forming a spatial couple, thereby overcoming the overturning moment caused by the overall lateral tilt of the upper body. The entire process is directly transmitted by the rigid linkages 501, completely eliminating the mechanical backlash caused by the differential of the traditional bevel gear set, ensuring the absolute accuracy of the lateral swaying posture.

[0045] Lower limb load-bearing and independent movement: The left hip drive unit 7 and right hip drive unit 8, located at the bottom, provide active driving force for the hip joints of both legs. Due to their special inverted Y-shaped arrangement, when the robot is walking, running, jumping, or experiencing external lateral impacts, the huge reaction force caused by the ground impact will smoothly converge upwards along the inclined axis of the left hip drive unit 7 and the right hip drive unit 8 and be transmitted to the high-rigidity cross-axis frame in the center and the support plates on both sides. This mechanical configuration cleverly transforms the lateral impact force, which might otherwise cause a destructive breaking moment to the parallel lower limbs, into internal compressive and tensile stresses of the structure, greatly enhancing the high load-bearing stiffness and impact resistance of the overall waist and hip module.

[0046] The universal joint 9 provides the lumbar joint structure with two orthogonal rotational degrees of freedom. One axis of rotation of the universal joint 9 is parallel to the robot's sagittal plane (X-axis), and the other axis of rotation is parallel to the coronal plane (Y-axis). The lower ends of the two sets of links 501 are hinged together to the inverted Y-shaped hip platform of the lower body, which is connected in the X-axis direction of the universal joint 9, via a joint self-aligning bearing 503.

[0047] Meanwhile, without departing from the core concept of this invention, the specific implementation of the humanoid robot hip module in this embodiment can be achieved by the following alternative solutions:

[0048] 1. Alternative to the differential mechanism connection hub (universal joint 9):

[0049] Implementation Plan: In the aforementioned plan, the core pivot for driving the hip joint movement via the connecting rod 501 between the right differential drive component 3 and the left differential drive component 4 is the "cross-axis mechanism". Alternatively, this pivot can be replaced with a ball joint mechanism or a multi-bearing composite universal joint.

[0050] Alternative effect: The ball joint can also release the rotational degrees of freedom in both the X and Y axes (and even include passive Z-axis rotation margin). Although its resistance to deformation under extremely high torque may be slightly inferior to that of a custom cross joint, the ball joint structure is smaller and lighter in size for humanoid robots with small to medium loads, and can serve as an effective alternative to the differential connection structure of this invention.

[0051] 2. Alternatives to the form and function of transmission components:

[0052] Form Alternative: In the aforementioned scheme, link 501 is typically a rigid straight rod. As an alternative, link 501 can be designed as a curved rod with a specific curvature (irregular link). When the robot needs to perform extreme large-angle lateral swing or forward tilt at its waist, the curved rod design can effectively avoid mechanical and physical interference between the link body and the side motor plates or the central main frame, further expanding the joint's working space.

[0053] Functional Alternative: The aforementioned solution uses a purely rigid linkage. As an alternative, a series of elastic elements (such as disc springs or polyurethane buffer pads) can be integrated inside the linkage. When the robot lands after running or jumping, generating instantaneous extreme impact forces, this "micro-elastic linkage" can absorb the peak destructive torque within milliseconds, protecting the reducer gears from damage and achieving flexible differential control.

[0054] 3. Adjustable alternatives to the inverted Y-shaped hip (left hip drive 7 and right hip drive 8) mounting base:

[0055] Implementation Plan: In the aforementioned plan, the left hip drive component 7 and the right hip drive component 8 are "fixed" to the central base in an inverted Y-shape (the included angle is a factory-set fixed value). Alternatively, the mounting flange of the drive component can be connected to the main frame using arc-shaped sliding bolts, end-face gear meshing connection, or a multi-stage adjustable pin hole structure.

[0056] Alternative Effect: This alternative solution makes the "split angle" of the inverted Y-shaped structure an adjustable parameter. Researchers can physically alter the chassis's stress geometry to suit different tasks the robot will perform (e.g., adjusting the angle to decrease for walking through narrow passages, and increasing the angle for heavy-duty squats to enhance lateral stability).

[0057] 4. Alternatives to driver source types:

[0058] Implementation Plan: In the aforementioned plan, all drive components are assumed to use an integrated joint consisting of a rotary direct-drive / quasi-direct-drive motor and a reducer. Alternatively, in heavy-duty applications, the drive source can be replaced with a rotary micro hydraulic swing cylinder.

[0059] Alternative effect: The hydraulic swing cylinder can provide torque density and shock resistance far exceeding that of the motor. As long as the overall external configuration still maintains the "parallel differential linkage" and "inverted Y-shaped arrangement" described in this invention, the hydraulic drive scheme also falls within the protection scope of this invention.

[0060] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A hip and waist module for a humanoid robot based on linkage differential and inverted Y-shaped configuration, characterized in that: include A yaw and differential attitude control assembly includes a positioning frame. A waist drive component is fixed at the top center of the positioning frame along the Z-axis. The waist drive component is used to realize the robot's steering. A right differential drive component and a left differential drive component are fixed on both sides of the positioning frame along the Y-axis and are symmetrically arranged. The right differential drive component and the left differential drive component are connected to a transmission assembly to realize the pitch movement of the robot's waist. An inverted Y-shaped hip joint bearing assembly includes a positioning frame two, on which a left hip drive component and a right hip drive component are symmetrically fixed, and the left hip drive component and the right hip drive component are arranged in an inverted Y shape.

2. The humanoid robot hip module based on linkage differential and inverted Y-shaped configuration according to claim 1, characterized in that: The transmission components are arranged in parallel in two sets, including a connecting rod and a fisheye joint rotatably connected to one end of the connecting rod. The other end of the connecting rod is hinged to a joint self-aligning bearing fixed to the top of the positioning frame two. The other ends of the two sets of fisheye joints are respectively connected to the output shafts of the right differential drive and the left differential drive, which are arranged inward.

3. The humanoid robot hip module based on linkage differential and inverted Y-shaped configuration according to claim 1, characterized in that: The top of the positioning frame 2 is fixed with a cross universal joint, which is coaxially arranged with the waist drive component. One of the rotation axes of the cross universal joint is parallel to the Y-axis direction where the right differential drive component and the left differential drive component are located.

4. The humanoid robot hip module based on linkage differential and inverted Y-shaped configuration according to claim 3, characterized in that: The universal joint and the two rotary joints on the rotation axis, which are parallel to the Y-axis direction of the right differential drive and the left differential drive, are fixed to the positioning frame.

5. The humanoid robot hip module based on linkage differential and inverted Y-shaped configuration according to claim 1, characterized in that: The waist drive, right differential drive, left differential drive, left hip drive, and right hip drive all adopt an integrated joint of motor and reducer.

6. The humanoid robot hip module based on linkage differential and inverted Y-shaped configuration according to claim 1, characterized in that: Both the positioning frame one and the positioning frame two adopt a topological hollow design for weight reduction.

7. The humanoid robot hip module based on linkage differential and inverted Y-shaped configuration according to claim 1, characterized in that: The positioning frame one and positioning frame two can be prepared by any of the following methods: CNC machining of aerospace aluminum alloy / titanium alloy, integral molding of carbon fiber reinforced composite material, or internal dot matrix filling molding by metal 3D printing.

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