Foot driving structure for humanoid robot and pitching motion method

Abstract

The invention discloses a foot driving structure for a humanoid robot and a pitching motion method, and belongs to the field of humanoid robots, the foot driving structure comprises a sole and a support frame fixed at the top end of the sole, and main bodies of a first motor and a second motor are fixed on two sides of the support frame in an up-down staggered manner; a first connecting line between the main body center point of the first motor and the main body center point of the second motor and a second connecting line between the output shaft center point of the first motor and the output shaft center point of the second motor intersect to form an intersection point, and the intersection point is located on the center line of the rear side of the supporting frame; the output axes of the first motor and the second motor are symmetrically arranged in a non-parallel mode, so that couple moment applied to the supporting frame is symmetrically balanced on the horizontal plane when the two motors are driven. According to the foot driving structure for the humanoid robot and the pitching motion method, through the dual-motor space geometry optimization layout, the integrated radial anti-loosening cover plate design and the directional lightweight groove structure, collaborative improvement of the mechanical property, the transmission reliability and the lightweight is achieved.

Description

Technical Field

[0001] This invention relates to the field of humanoid robot technology, and in particular to a foot-driven structure and pitch motion method for a humanoid robot. Background Technology

[0002] Humanoid robots, as a cutting-edge direction and core research hotspot in the field of robotics, rely heavily on their lower limb motor systems. The performance of these systems directly determines whether a robot can achieve human-like, flexible movement. The foot drive mechanism, as the end effector of lower limb movement, is particularly crucial influencing a robot's walking stability, terrain adaptability, and energy efficiency. The feet need to mimic the movement characteristics of the human foot, possessing multi-degree-of-freedom motion capabilities. Specifically, the forward and backward pitching of the foot relative to the ankle joint ensures adaptation to changes in ground elevation during walking, while lateral swaying corrects posture on uneven surfaces. These two aspects together form the basis of a human-like, flexible gait. To achieve this dual-degree-of-freedom motion, the industry commonly adopts a technical approach that integrates multiple drive units (such as servo motors) at the foot or ankle joint. Among these, dual-motor drives have become the mainstream solution due to their relatively simple structure and clear control logic.

[0003] Currently, the core structural design of dual-motor drive solutions involves placing two drive motors side-by-side on the foot or its connecting parts, and controlling the foot's movement in the pitch and lateral directions via linkages and other transmission components. However, in practical applications, this design faces three major technological challenges in balancing device compactness and high performance requirements, as follows: 1. Inherent contradiction between spatial layout and mechanical performance: To accommodate the limited installation space of the humanoid robot's feet, existing designs typically employ a close side-by-side arrangement of the two motors, resulting in parallel output axes and a short distance between them. This simple side-by-side layout has significant mechanical defects: when driving the foot to perform combined pitch and lateral movements, the transmission path of the driving torque is asymmetrically distributed, with uneven lever arm distribution, leading to asymmetrical torsional stress at the motor mounting points and connection nodes of the support frame. Long-term repeated application of this stress can easily induce structural fatigue cracks, severely affecting the device's service life and operational reliability. Simultaneously, the side-by-side layout fails to optimize the matching between the overall center of gravity of the motor assembly and the force center of the foot, requiring additional eccentric load to be overcome during driving. This not only increases the driving load on the motors but also reduces the dynamic response sensitivity of gait adjustment, resulting in energy waste.

[0004] 2. Insufficient Reliability of Transmission Connections: The connection between the motor output and the connecting rod is a critical link in power transmission. Current technologies commonly use key connections, fastener connections (such as bolt fixing), or direct sleeve connections to secure them. However, under complex conditions such as dynamic robot walking, obstacle crossing, ground impacts, or rapid posture adjustments, this connection must withstand complex radial and axial alternating loads with large instantaneous impact forces and varying directions. Traditional connection methods can only achieve circumferential torque transmission or simple axial fixation, lacking an effective radial displacement constraint structure—key connections lack radial limiting functions, fasteners are prone to loosening due to vibration, and direct sleeve connections have gaps that can lead to radial movement. These defects create a risk of loosening, wobbling, or even connection failure between the connecting rod and the motor output, directly threatening the overall stability and safety of the robot's operation, and in severe cases, potentially leading to gait instability.

[0005] 3. The Challenge of Balancing Lightweight Design with Structural Strength: As the end effector, the weight of the foot actuator directly impacts the robot's overall energy consumption and lower limb joint load. Foot inertial load is amplified with joint movement, exacerbating energy consumption in the lower limb actuator and increasing joint wear. Therefore, lightweight design is a crucial objective for foot actuators. A common industry practice is to create weight-reduction holes or grooves in the support structure. However, existing weight-reduction designs lack systematic mechanical analysis and often suffer from improper placement or shape. For example, creating weight-reduction structures in critical stress areas such as motor mounting areas and force transmission paths directly weakens the rigidity and structural integrity of the support structure. Some designs, in pursuit of weight reduction, blindly expand the weight-reduction area, potentially damaging the motor's heat dissipation channels and affecting long-term stable operation. Ultimately, an optimal balance cannot be achieved between weight reduction requirements and support rigidity and heat dissipation performance.

[0006] In summary, existing humanoid robot foot drive devices still have significant shortcomings in terms of spatial geometry optimization of dual-motor drive layout, radial constraint enhancement of transmission connection, and synergistic design of lightweight and structural strength. As a result, the robot's motion stability, action response speed, structural durability, and overall energy efficiency are difficult to meet the application requirements in complex scenarios. Summary of the Invention

[0007] The purpose of this invention is to provide a foot-driven structure and pitch motion method for a humanoid robot, thereby solving the aforementioned technical problems.

[0008] To achieve the above objectives, the present invention provides a foot-driven structure for a humanoid robot, including a foot and a support frame fixed to the top of the foot. The main bodies of a first motor and a second motor are fixedly and alternately on both sides of the support frame. The output shafts of the first motor and the second motor pass through the support frame and are rotatably connected to the top of a first link and the top of a second link, respectively, via flanges. The bottom ends of the first link and the second link are rotatably connected to the foot. The first link and the first motor are respectively located on both sides of the support frame, and the second link and the second motor are respectively located on both sides of the support frame. The first line connecting the center point of the main body of the first motor and the center point of the main body of the second motor intersects with the second line connecting the center point of the output shaft of the first motor and the center point of the output shaft of the second motor to form an intersection point, which is located on the center line of the rear side of the support frame. By symmetrically arranging the output shafts of the first and second motors in a non-parallel manner, the torque applied to the support frame during dual-motor drive is symmetrically balanced in the horizontal plane.

[0009] Preferably, the center point of the output shaft of the first motor and the center point of the main body of the second motor form a drive center line, which is parallel to the side-view center line of the foot, and there is a certain distance between the drive center line and the side-view center line.

[0010] Preferably, the ratio of the distance between the drive center line and the side-view center line to the side-view width of the foot is 1:10-3:10.

[0011] Preferably, the second motor is located diagonally below the first motor, and the length of the second link is less than the length of the first link.

[0012] Preferably, the side of the flange away from the support frame is also covered with a radial anti-loosening component. The radial anti-loosening component is a fan-shaped plate structure. The edge of the fan-shaped plate structure is fixedly connected to the body of the first motor or the second motor. The fan-shaped plate structure protrudes outward to form a positioning plate corresponding to the output shaft position of the first motor or the second motor. The positioning plate is movably connected to the journal of the output shaft or the flange.

[0013] Preferably, the positioning plate and the output shaft are either clearance-fitted or rotationally fitted. Alternatively, the positioning plate and the flange may have a clearance fit or a rotational fit.

[0014] Preferably, the total area of ​​the flange surface covered by the fan-shaped plate structure accounts for 30%-60%.

[0015] Preferably, the coverage area of ​​the fan-shaped plate-like structure At least one of the following conditions must be met: Condition 1: ; Condition 2: ; In the formula, This represents the total area of ​​the end face of the output shaft; This indicates the total surface area of ​​the flange.

[0016] Preferably, both the support frame below the first motor and the support frame below the second motor have multiple elongated weight-reducing grooves that extend downward and are arranged in a matrix.

[0017] A method for pitch motion of a humanoid robot using a foot-driven structure includes the following steps: S1, Target pitch angle for receiving footprint instruction; S2, Command Calculation: Based on the target pitch angle Based on the kinematic model of the leg structure, the target differential angle between the first motor and the second motor driving the foot is calculated. ; S21. Based on the target pitch angle And the predetermined kinematic relationship function, calculate the target differential angle. : ; In the formula, This indicates the distance from the center of foot rotation to the connection point between the link and the foot. and These represent the lengths of the first and second links, respectively. Indicates the bias correction factor; Indicates the offset distance between the drive centerline and the foot's side-view center of gravity line; Indicates the lateral width of the foot; S22, Based on the target differential angle and the midfoot reference angle Calculate the first target rotation angle of the first motor respectively. The second target angle of the second motor : ; ; S3. Motor control steps: Control the first motor to rotate to the first target angle. Simultaneously control the second motor to rotate to the second target angle. This achieves differential rotation of the dual motors, driving the first and second connecting rods on both sides through corresponding flanges to generate differential displacement, thereby causing the foot to rotate around its central axis or mechanical equilibrium point at a pitch angle relative to the target. The corresponding pitching motion.

[0018] Therefore, the present invention, employing the aforementioned foot-driven structure and pitch motion method for a humanoid robot, has the following beneficial effects: 1. Optimize mechanical transmission and extend device life: The intersection of the center line connecting the output end and non-output end of the dual motors is located on the vertical center line of the support frame, forming a symmetrical force layout, eliminating asymmetrical torsional stress, reducing stress concentration and fatigue risk in key parts of the support frame, and extending the overall service life of the device. 2. Improved dynamic response speed: The drive center line is parallel to the foot's side-view center line in the side view (the offset distance is 1:10 to 3:10 to the foot's side-view width ratio), which reduces the effective rotational inertia of the foot around the drive axis, allowing the motor to drive the foot to complete the movement with less torque, thus improving the agility and response speed of gait adjustment. 3. Enhanced static and dynamic stability: The offset design of the drive center line and the center of gravity line forms a natural lever arm, which automatically generates a reverse restoring torque when the body tilts, significantly improving the robot's static standing stability and dynamic anti-interference ability in scenarios such as walking on uneven ground and being pushed by external forces. 4. Enhanced reliability of transmission connection: The radial anti-loosening component provides effective radial constraint on the flange and connecting rod, avoiding the risk of movement and loosening under dynamic working conditions (impact, vibration). Moreover, this structure is integrated into the motor output end, without increasing the length of the transmission chain, thus maintaining the compactness of the device. 5. Achieving a balance between lightweight and structural strength: Long, spaced, weight-reducing grooves are set in the non-core load-bearing area below the motor, which reduces the inertial load of the device and the energy consumption of the robot, while avoiding key stress points and maintaining support stiffness, structural integrity and bending resistance. 6. Improved energy efficiency: Reduced internal loss of driving force and additional eccentric load, making the driving force more efficiently converted into the expected movement of the foot. At the same time, the cover plate area design takes into account the heat dissipation needs of the motor, further optimizing the overall energy efficiency.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of a foot-driven structure for a humanoid robot according to the present invention; Figure 2 This is a rear view of a foot-driven structure for a humanoid robot according to the present invention. Figure 3 This is a side view of a foot-driven structure for a humanoid robot according to the present invention; Figure 4 This is a schematic diagram of the radial anti-loosening component structure of a foot drive structure for a humanoid robot according to the present invention.

[0021] Figure Labels 1. Foot; 2. Support frame; 3. First motor; 4. Second motor; 5. First connecting rod; 6. Second connecting rod; 7. Radial anti-loosening component; 71. Positioning plate; 8. Long strip-shaped weight-reducing groove. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the embodiments of the present invention and are not intended to limit the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0023] It should be noted that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as a process, method, system, product, or server that includes a series of steps or units, not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or device.

[0024] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0025] like Figures 1-4 As shown, a foot-driven structure for a humanoid robot includes a foot 1 and a support frame 2 fixed to the top of the foot 1. The main bodies of a first motor 3 and a second motor 4 are fixed to the two sides of the support frame 2 in an alternating manner. The output shafts of the first motor 3 and the second motor 4 pass through the support frame 2 and are rotatably connected to the top of a first connecting rod 5 and the top of a second connecting rod 6 via flanges, respectively. The bottom ends of the first connecting rod 5 and the second connecting rod 6 are rotatably connected to the foot 1. The first connecting rod 5 and the first motor 3 are respectively placed on the two sides of the support frame 2, and the second connecting rod 6 and the second motor 4 are respectively placed on the two sides of the support frame 2. A first line connecting the center point of the main body of the first motor 3 and the center point of the main body of the second motor 4 intersects with a second line connecting the center point of the output shaft of the first motor 3 and the center point of the output shaft of the second motor 4 to form an intersection point, which is located on the rear center line of the support frame 2. By using the non-parallel symmetrical layout of the output shafts of the first motor 3 and the second motor 4, the torque applied to the support frame 2 during dual-motor drive is symmetrically balanced in the horizontal plane.

[0026] This embodiment adopts the above-mentioned structural layout. On the one hand, the staggered arrangement of the upper and lower parts makes the main body of the two motors and the output shaft form a "non-coplanar but symmetrical" spatial posture, providing structural conditions for the non-parallel setting of the output shaft. On the other hand, the design of the connecting rod and the motor being placed on opposite sides allows the transmission path of the driving torque to form a perpendicular force relationship with the force plane of the support frame 2, avoiding lateral offset during torque transmission and ensuring that the force flow is transmitted along the preset direction.

[0027] Specifically, the output shafts of the two motors are arranged in a non-parallel layout. Combined with the staggered and side-connected structure, the driving torque transmitted from the first motor 3 to the first connecting rod 5 via the flange and the driving torque transmitted from the second motor 4 to the second connecting rod 6 form a "pair of opposing torques" on the horizontal plane: the driving torque of the first motor 3 acts around its output shaft, and because the connecting rod and the motor are located on opposite sides, the direction of the torque points towards the inside of the support frame 2; the driving torque of the second motor 4 is opposite to but symmetrical to the first motor 3, and the two form a "pull-off" torque on the horizontal plane. The non-parallel output shafts allow the surface of the torque to precisely fit with the support plane of the support frame 2, avoiding the decomposition of the torque into lateral components, and ensuring that all driving forces participate in the pitching / swinging motion of the foot 1 without any additional force loss.

[0028] Furthermore, the rear centerline of support frame 2 is the symmetrical reference line for structural stress. The intersection point falling on this line indicates that the installation reference (main body center point) and power output reference (output shaft center point) of the two motors are both symmetrical about this centerline, forming a "double reference symmetry" pattern. This symmetrical relationship makes the spatial position and output direction of the two motors mirror-distributed relative to the center of support frame 2, ensuring that the magnitude of the subsequent driving torque is equal and the direction is opposite, providing a geometric premise for torque balance.

[0029] Specifically, since the spatial layout of the two motors is symmetrical about the rear centerline of the support frame 2 and the torque transmission path is symmetrical, the two torques applied to the support frame 2 when driven by the two motors satisfy the balance condition of "equal in magnitude, opposite in direction, and coplanar in action": the torque generated by the first motor 3 attempts to twist the support frame 2 to one side, while the torque generated by the second motor 4 twists to the other side, and the two cancel each other out. This balance completely eliminates the "additional torsional torque" caused by the asymmetry of the lever arm in the traditional parallel layout, avoids fatigue damage to the support frame 2 due to asymmetric stress during long-term operation, and ensures that the driving torque is converted into the kinetic energy of the foot 1 without internal loss.

[0030] The center point of the output shaft of the first motor 3 and the center point of the main body of the second motor 4 form the drive center line. The drive center line is parallel to the side-view center line of gravity on the foot 1, and there is a certain distance between the drive center line and the side-view center line. The above parallel relationship ensures that the drive center line and the direction of gravity of the foot 1 (distributed along the center line of gravity) form a fixed lever arm angle, avoiding the decomposition of the drive torque into a lateral component due to the two lines not being parallel. If the two lines intersect or are not parallel, the torque output by the motor will be split into an ineffective direction, causing energy loss and possibly causing the foot 1 to wobble sideways. This ensures that the composite torque generated by the dual-motor drive always acts in the preset pitch / sway direction, with a clear force transmission path, ensuring that all the driving force is used to control the posture of the foot 1, laying a structural foundation for subsequent dynamic optimization and stable torque generation.

[0031] Furthermore, by adjusting the distance between the drive center point and the side-view center of gravity line, the mass distribution of foot 1 can be made more concentrated relative to the drive axis (equivalent to shortening the distance of some mass to the axis), thereby reducing the effective rotational inertia of foot 1 around the drive axis. According to the dynamic formula, after the rotational inertia is reduced, the motor does not need to output excessive torque to drive foot 1 to quickly complete pitch or lateral movements, significantly reducing the drive load, improving the agility of gait adjustment and dynamic response speed, while reducing energy consumption and optimizing overall energy efficiency.

[0032] Meanwhile, the reserved distance naturally forms a fixed lever arm, which is the core of self-stabilization: when the robot stands statically, gravity acts along the center line, generating a stabilizing torque on the drive center line through the lever arm, keeping foot 1 in a natural ground-planting posture and avoiding the tendency to tip over when there is no external force; when the robot walks dynamically (such as crossing uneven ground) or is pushed by an external force causing the body to tilt, the relative position of the gravity line and the drive center line shifts, and the aforementioned lever arm automatically generates a restoring torque opposite to the tilt direction—the larger the tilt angle, the more obvious the corrective effect of the restoring torque, which can quickly pull the posture of foot 1 back to a balanced state, greatly enhancing the robot's static stability and dynamic anti-interference ability in complex scenarios.

[0033] The ratio of the distance between the drive center line and the side-view center line to the side-view width of the foot 1 is 1:10-3:10. In this embodiment, the drive center line is located to the right or left of the side-view center line of the foot 1.

[0034] If the ratio of the distance between the drive center line and the lateral center of gravity line to the lateral width of foot 1 is less than 1:10, then the most basic offset effect is lacking, and dynamic response improvement and stabilization torque cannot be achieved. If the ratio of the distance between the drive center line and the lateral center of gravity line to the lateral width of foot 1 is greater than 3:10, then the following problems may occur: 1. It may cause severe uneven force distribution on the left and right sides of the foot 1 structure, potentially leading to structural deformation or abnormal wear. 2. It may result in excessively large restoring torque, which may cause "over-stability" and clumsiness during fine motor control, hindering agile movements. Therefore, the ratio of the distance between the drive center line and the lateral center of gravity line to the lateral width of foot 1 should be chosen to be 1:10-3:10.

[0035] The second motor 4 is located diagonally below the first motor 3, and the length of the second link 6 is less than the length of the first link 5.

[0036] The flange is also covered with a radial anti-loosening component 7 on the side away from the support frame 2. The radial anti-loosening component 7 is a fan-shaped plate structure. The edge of the fan-shaped plate structure is fixedly connected to the main body of the first motor 3 or the second motor 4. The fan-shaped plate structure protrudes outward to form a positioning plate 71 corresponding to the output shaft position of the first motor 3 or the second motor 4. The positioning plate 71 is movably connected to the journal of the output shaft or the flange.

[0037] The positioning plate 71 is either clearance-fitted or rotationally-fitted with the output shaft; The positioning plate 71 has a clearance fit or a rotational fit with the journal of the flange.

[0038] The flange surface area covered by the fan-shaped plate structure accounts for 30%-60% of the total area, which can prevent loosening and avoid negative impacts on connection, heat dissipation and weight reduction.

[0039] Preferably, the coverage area of ​​the fan-shaped plate-like structure At least one of the following conditions must be met: Condition 1: ; Condition 2: ; In the formula, This represents the total area of ​​the end face of the output shaft; This indicates the total surface area of ​​the flange.

[0040] When only condition 1 is met, it can be ensured that the radial anti-loosening component 7 can provide sufficient constraint coverage without excessively hindering heat dissipation or interfering with the normal range of motion of the linkage, thus achieving the best balance between constraint effect and functional compatibility.

[0041] When only condition 2 is met, the purpose of preventing loosening can be achieved with the smallest area, thereby reducing weight.

[0042] Multiple elongated weight-reducing grooves 8, extending downwards and arranged in a matrix, are provided on the support frame 2 below the first motor 3 and the support frame 2 below the second motor 4. By placing these grooves in the non-core load-bearing area below the motors, a significant reduction in local weight is achieved, thereby reducing the inertial load and drive energy consumption during robot movement. Simultaneously, this design avoids weakening critical load-bearing components such as the motor mounting holes, ensuring overall support rigidity.

[0043] A method for pitch motion of a humanoid robot using a foot-driven structure includes the following steps: S1, Target pitch angle of foot 1 instruction; S2, Command Calculation: Based on the target pitch angle Based on the kinematic model of the leg structure, the target differential angle between the first motor 3 and the second motor 4 driving the foot 1 is calculated. ; S21. Based on the target pitch angle And the predetermined kinematic relationship function, calculate the target differential angle. : ; In the formula, This indicates the distance from the rotation center of foot 1 to the connection point of the link-foot 1; and These represent the lengths of the first link 5 and the second link 6, respectively. Indicates the bias correction factor; This indicates the offset distance between the drive centerline and the center of gravity line viewed from the side of the foot. This indicates the lateral width of foot 1; S22, Based on the target differential angle and the mid-foot reference angle Calculate the first target rotation angle of the first motor 3 respectively. The second target angle of the second motor 4 : ; ; S3, Motor Control Steps: Control the first motor 3 to rotate to the first target angle. Simultaneously, control the second motor 4 to rotate to the second target angle. This achieves differential rotation of the dual motors, driving the first link 5 and the second link 6 on both sides through corresponding flanges to generate differential displacement, thereby causing the foot 1 to generate a pitch angle relative to the target around its central axis or mechanical equilibrium point. The corresponding pitching motion.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A foot-driven structure for a humanoid robot, comprising a foot and a support frame fixed to the top of the foot, characterized in that: The main bodies of the first motor and the second motor are fixed on both sides of the support frame in an alternating manner. The output shafts of the first motor and the second motor pass through the support frame and are rotatably connected to the top of the first connecting rod and the top of the second connecting rod respectively via flanges. The bottom of the first connecting rod and the bottom of the second connecting rod are rotatably connected to the foot. The first connecting rod and the first motor are placed on both sides of the support frame, and the second connecting rod and the second motor are placed on both sides of the support frame. The first line connecting the center point of the main body of the first motor and the center point of the main body of the second motor intersects with the second line connecting the center point of the output shaft of the first motor and the center point of the output shaft of the second motor to form an intersection point, which is located on the center line of the rear side of the support frame. By symmetrically arranging the output shafts of the first and second motors in a non-parallel manner, the torque applied to the support frame during dual-motor drive is symmetrically balanced in the horizontal plane.

2. The foot-driven structure for a humanoid robot according to claim 1, characterized in that: The center point of the output shaft of the first motor and the center point of the main body of the second motor form the drive center line. The drive center line is parallel to the side-view center line of the foot, and there is a certain distance between the drive center line and the side-view center line.

3. The foot-driven structure for a humanoid robot according to claim 2, characterized in that: The ratio of the distance between the drive center line and the lateral center line to the lateral width of the foot is 1:10-3:

10.

4. The foot-driven structure for a humanoid robot according to claim 1, characterized in that: The second motor is located diagonally below the first motor, and the length of the second link is less than the length of the first link.

5. The foot-driven structure for a humanoid robot according to claim 1, characterized in that: The flange is also covered with a radial anti-loosening component on the side away from the support frame. The radial anti-loosening component is a fan-shaped plate structure. The edge of the fan-shaped plate structure is fixedly connected to the body of the first motor or the second motor. The fan-shaped plate structure protrudes outward to form a positioning plate corresponding to the output shaft position of the first motor or the second motor. The positioning plate is movably connected to the journal of the output shaft or the flange.

6. The foot-driven structure for a humanoid robot according to claim 5, characterized in that: The positioning plate is fitted with the output shaft with a clearance fit or a rotational fit. Alternatively, the positioning plate and the flange may have a clearance fit or a rotational fit.

7. The foot-driven structure for a humanoid robot according to claim 5, characterized in that: The total area of ​​the flange surface covered by the fan-shaped plate structure accounts for 30%-60%.

8. The foot-driven structure for a humanoid robot according to claim 7, characterized in that: Coverage area of ​​fan-shaped plate-like structure At least one of the following conditions must be met: Condition 1: ; Condition 2: ; In the formula, This represents the total area of ​​the end face of the output shaft; This indicates the total surface area of ​​the flange.

9. The foot-driven structure for a humanoid robot according to claim 1, characterized in that: Multiple elongated weight-reducing grooves extending downwards and arranged in a matrix at intervals are provided on the support frame below the first motor and the support frame below the second motor.

10. A pitch motion method for a humanoid robot using a foot-driven structure as described in any one of claims 1-9, characterized in that: Includes the following steps: S1, Target pitch angle for receiving footprint instruction; S2, Command Calculation: Based on the target pitch angle Based on the kinematic model of the leg structure, the target differential angle between the first motor and the second motor driving the foot is calculated. ; S21. Based on the target pitch angle And the predetermined kinematic relationship function, calculate the target differential angle. : ； In the formula, This indicates the distance from the center of foot rotation to the connection point between the link and the foot. and These represent the lengths of the first link and the second link, respectively. Indicates the bias correction factor; Indicates the offset distance between the drive centerline and the foot's side-view center of gravity line; Indicates the lateral width of the foot; S22, Based on the target differential angle and the midfoot reference angle Calculate the first target rotation angle of the first motor respectively. The second target angle of the second motor : ； ； S3. Motor control steps: Control the first motor to rotate to the first target angle. Simultaneously control the second motor to rotate to the second target angle. This achieves differential rotation of the dual motors, driving the first and second connecting rods on both sides through corresponding flanges to generate differential displacement, thereby causing the foot to rotate around its central axis or mechanical equilibrium point at a pitch angle relative to the target. The corresponding pitching motion.

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