Foot gimbal base, foot ankle assembly, and small humanoid robot

Abstract

The application discloses a foot universal joint base, a foot and ankle assembly and a small humanoid robot. The foot universal joint base comprises a base body, a front hinge wing and a rear hinge wing which are arranged at intervals along the front and rear directions of the foot and form a universal joint mounting space between the two, four candidate hinge positions are formed on the two sides of the front and rear hinge wings in the width direction, two positions are selected from the opposite sides in the width direction of the foot, and first and second rocker hinge rods which extend outward in the width direction are integrally formed and used for mounting a ball head. The rocker hinge rod and the universal joint support structure share the foot universal joint base, the ball head and the universal joint are positioned by the same reference, the assembly cumulative error, the connection looseness and the space occupation are reduced, the double rocker cooperative control is improved, and the operation noise is reduced.

Description

Technical Field

[0001] This application relates to the field of humanoid robot technology, and more particularly to a foot universal joint base, ankle assembly, and small humanoid robot for a small humanoid robot. Background Technology

[0002] The ankle area of ​​a humanoid robot connects the legs and feet, allowing the feet to pitch and sway relative to the lower legs while bearing the robot's load. In small humanoid robots, the ankle area has limited space, requiring the universal joint, two drive rockers, and their ball joint connection structure to be arranged collaboratively within this confined space. The positional relationship of the two ball joints relative to the universal joint also affects the coordinated control of the foot's posture by the two rockers.

[0003] In existing foot and ankle structures, the lower ball joint of the drive rocker arm is typically mounted on the foot plate or near the ankle via an independent rocker arm bracket, while the universal joint is mounted by another support structure. The independent rocker arm bracket and the universal joint support structure are manufactured, positioned, and assembled separately, which easily leads to accumulated assembly errors. After repeated stress, clearances may also develop at the connection interfaces, causing the positions of the two ball joints relative to the universal joint's rotation center to deviate. This increases the difficulty of motion control calibration and affects the consistency of the dual-rocker coordinated drive.

[0004] Furthermore, during robot walking and posture adjustment, the joystick ball joint bears repeatedly changing push and pull loads in both direction and magnitude. The independent joystick bracket, fasteners, and their connection interfaces may collide due to loosening or gaps, generating mechanical noise. The independent joystick bracket, universal joint support structure, and corresponding fasteners and assembly operation space also occupy a significant amount of ankle space, which is not conducive to reducing the volume of the ankle structure. Summary of the Invention

[0005] This application addresses the technical problem that the rocker hinge structure in the ankle region of a small humanoid robot is affected by accumulated assembly errors and connection gaps, which affect the coordinated motion control of the dual rockers and easily generate loosening and collision noise under alternating loads. It provides a foot universal joint base, an ankle assembly, and a small humanoid robot.

[0006] In one technical solution, a foot universal joint base for a small humanoid robot is provided. The foot universal joint base includes a base body, a front hinge wing, and a rear hinge wing. The front and rear hinge wing are spaced apart on the base body along the front-rear direction of the foot, forming a universal joint mounting space for mounting the universal joint. The front and rear hinge wing each have sides located on the left and right sides in the width direction of the foot. The left, right, left, and right sides of the front and rear hinge wing constitute four candidate hinge positions. Two of the four candidate hinge positions are located on opposite sides in the width direction of the foot, and each has an integrally formed first rocker hinge rod and second rocker hinge rod. The first and second rocker hinge rods extend outward from their respective candidate hinge positions along the width direction of the foot and are used to mount ball joints that connect with the first and second rockers respectively.

[0007] By integrating the two rocker arm hinges with the hinge wing used to support the universal joint into a single structure, the relative positions of the ball joint and the universal joint can be determined by the same universal joint base, eliminating the need for separate rocker arm brackets and their fastening structures.

[0008] In one technical solution, the first rocker arm hinge and the second rocker arm hinge are integrally formed on opposite sides of the same hinge wing in the width direction of the foot. The hinge positions of the two rockers are provided by the same hinge wing, which can form a unified machining and assembly reference, and allow the rocker arm loads on both sides of the ankle to converge into the base body through the same hinge wing.

[0009] In one technical solution, the same hinge wing is a rear hinge wing. In this case, the first rocker hinge rod and the second rocker hinge rod are respectively set on the left and right sides of the rear hinge wing, and the front hinge wing is located in front of the two rocker hinge rods, so that the universal joint support part and the two rocker ball joint parts are staggered in the front-back direction of the foot, avoiding the corresponding installation space from overlapping each other.

[0010] In one technical solution, the central axes of the first rocker hinge rod and the second rocker hinge rod coincide. The two rocker hinge rods have a common axial reference, which facilitates that the ball heads mounted on both sides are at the same or close height, and makes the two rockers form a relatively balanced action position in the width direction of the foot.

[0011] In one technical solution, the base body, front hinge wing, rear hinge wing, first rocker hinge rod, and second rocker hinge rod are integrally formed. This integral structure eliminates the fastening connection between the rocker hinge rod and the hinge wing, allowing the rocker load to be transferred to the base body along the continuous structure, and preventing the rocker hinge rod from loosening.

[0012] In one technical solution, the first rocker arm hinge and the second rocker arm hinge each include a main body section integrally connected to the corresponding hinge wing and an assembly section connected to the outer end of the main body section. The outer diameter of the assembly section is smaller than the outer diameter of the main body section. The main body section is used to receive the load transmitted from the ball head, and the smaller-diameter assembly section is used to pass through the ball head, forming a step between the main body section and the assembly section for axial positioning of the ball head.

[0013] In one technical solution, the foot universal joint base also includes a first ball head and a second ball head respectively installed on the first rocker hinge rod and the second rocker hinge rod. The first ball head and the second ball head are respectively provided with through holes for the corresponding assembly sections to pass through. The outer end of each assembly section is provided with fasteners to prevent the corresponding ball head from disengaging outward along the assembly section. The ball head is limited by a step on one side of the main body section and the fasteners at the outer end of the assembly section, which can maintain the installation position of the ball head while allowing the corresponding rocker to form a ball-joint connection.

[0014] In one technical solution, a foot and ankle assembly for a small humanoid robot is provided, including a foot plate, a lower leg connector, a universal joint, a first rocker arm, a second rocker arm, a first ball joint, a second ball joint, and the aforementioned foot universal joint base. The universal joint is disposed in the universal joint mounting space and connected to the lower leg connector. The foot universal joint base, the universal joint, and the lower leg connector together form a pre-assembled ankle module that can be integrally installed on the foot plate. The foot universal joint base is detachably connected to the foot plate. The first ball joint is mounted on the first rocker arm hinge, and the second ball joint is mounted on the second rocker arm hinge. The first rocker arm is ball-jointed to the first ball joint, and the second rocker arm is ball-jointed to the second ball joint. Thus, the universal joint and the lower leg connector can be assembled and inspected on the foot universal joint base before being integrally installed onto the foot plate along with the foot universal joint base.

[0015] In one technical solution, the base body is provided with a foot plate connecting part, and the ankle pre-installed module is detachably connected to the foot plate through the foot plate connecting part. The foot plate connecting part provides the ankle pre-installed module with a positioning and fastening position corresponding to the foot plate, which facilitates the overall assembly and disassembly of the ankle pre-installed module.

[0016] In one technical solution, the lower leg connector extends at least partially into the universal joint mounting space. The universal joint connects the lower leg connector to the foot universal joint base, allowing the lower leg connector to rotate relative to the foot universal joint base around a first and second rotation axis defined by the universal joint. The lower leg connector extends between the front and rear hinge wings, concentrating the connection structure of the two rotation axes within the universal joint mounting space.

[0017] In one technical solution, the first rocker hinge rod and the second rocker hinge rod are integrally formed on opposite sides of the rear hinge wing in the width direction of the foot, and extend outward in the width direction of the foot. Two ball joints are installed outward from the left and right sides of the rear hinge wing, and the universal joint mounting space is located between the two hinge wings, thereby separating the ball joint connection position from the central mounting area of ​​the universal joint.

[0018] In one technical solution, the universal joint defines a first rotation axis and a second rotation axis intersecting at a point. The centers of the first and second ball joints are symmetrical about a vertical plane passing through the intersection point and extending along the front-rear direction of the foot. This symmetry is about the vertical plane, with the two ball centers located on the left and right sides of the vertical plane, respectively, and the vertical distances from the two ball centers to the vertical plane are equal. The first and second rocker arms may have corresponding lateral lever arms.

[0019] In one technical solution, the line connecting the centers of the first and second ball heads extends along the width direction of the foot. The two ball centers are located on the same side of a vertical plane passing through the intersection point and extending along the width direction of the foot in the front-back direction, and the two ball centers are at the same height. This positional relationship allows the two ball heads to have the same front-back offset and height reference, facilitating the two rockers to apply mutually cooperating driving forces to the foot through unidirectional or differential movements.

[0020] In one technical solution, the distance from each ball center to a vertical plane passing through the intersection point and extending along the front-to-back direction of the foot is denoted as X; the distance from each ball center to a vertical plane passing through the intersection point and extending along the width direction of the foot is denoted as Y; and the distance from each ball center to a horizontal plane passing through the intersection point is denoted as Z, where Z is less than X and less than Y. This relationship ensures that the horizontal offset of the ball head relative to the universal joint rotation center is greater than the height offset, thus retaining the driving lever arm while avoiding an excessively high ball head position that would increase the vertical dimensions of the ankle structure.

[0021] In one technical solution, X is 1 / 3 to 1 / 2 of the maximum dimension of the footplate in the width direction of the foot. Therefore, the first and second ball heads can be positioned close to the left and right edges of the footplate, respectively, within the width of the footplate to obtain a relatively large lateral lever arm, while preventing the ball heads from extending beyond the width of the footplate.

[0022] In one technical solution, Y is 1 / 5 to 1 / 4 of the maximum dimension of the footplate in the anteroposterior direction of the foot. This anteroposterior offset causes the ball joint to form an anteroposterior lever arm relative to the universal joint rotation center for driving the foot's swing, and keeps the ball joint spaced from the front and rear ends of the footplate.

[0023] In one technical solution, the lower ends of the first and second rocker arms are respectively provided with hinge seats, and bearings are installed in the hinge seats. The first and second ball heads are respectively rotatably engaged with the corresponding bearings, so that the first and second rocker arms are respectively connected to the corresponding ball heads in a ball-joint connection. The bearings provide rotational support for the angle change of the rocker arm relative to the ball head, so that the rocker arm can adapt to the swing angle change generated when the ankle assembly moves around the two rotation axes.

[0024] In one technical solution, a retaining ring is provided on the side of the hinge seat facing the corresponding rocker arm hinge rod. The retaining ring is positioned on the side of the corresponding bearing facing the rocker arm hinge rod to axially limit the bearing. A fastener is provided at the outer end of the corresponding rocker arm hinge rod to prevent the corresponding ball head from disengaging outward along the rocker arm hinge rod. The retaining ring limits the bearing, and the fastener limits the ball head, ensuring that the rotational support structure on the rocker arm side and the ball head on the rocker arm hinge rod side remain in their respective assembly positions.

[0025] In one technical solution, a small humanoid robot is provided, including a body, legs connected to the body, and the aforementioned foot and ankle assembly connected to the legs; a lower leg connector is connected to the lower end of the legs, and the foot plate constitutes the foot support structure of the small humanoid robot.

[0026] In one technical solution, when the small humanoid robot is standing normally and its feet are in contact with the horizontal support surface, the vertical distance from the horizontal support surface to the highest point of the small humanoid robot is 0.6 meters to 1.2 meters.

[0027] In the above technical solution, the first rocker arm hinge and the second rocker arm hinge are directly formed on the front or rear hinge wing that supports the universal joint. The driving force generated by the first rocker and the second rocker is transmitted to the foot plate sequentially through the ball joint, the rocker arm hinge, the hinge wing, and the base body, without the need for an independent rocker arm bracket.

[0028] In terms of motion control, the installation positions of the universal joint and the two rocker ball joints are determined by the same universal joint base, which can reduce the cumulative error caused by the separate processing and assembly of the distributed supports, and make the actual positions of the two ball joints relative to the rotation center of the universal joint closer to the predetermined positions, thereby reducing the impact of position deviation on the coordinated motion control of the two rockers.

[0029] Regarding noise, the rocker arm and hinge wing are integrated, eliminating the need for fasteners between them. This prevents relative collisions due to loose connections, thus reducing mechanical noise during ankle operation. In terms of size, the rocker arm hinge structure shares the front hinge wing, rear hinge wing, and base body with the universal joint support structure, eliminating the need for a separate rocker arm bracket, its fasteners, and assembly space. This allows for centralized arrangement of ankle components, reducing the overall size of the ankle structure. Furthermore, the foot universal joint base, universal joint, and lower leg connector can be pre-assembled into an ankle module before being installed onto the footplate, reducing the limitations of limited space during assembly. The ball joint is axially restrained by the step between the main body and the assembly section, as well as the fasteners at the outer end of the assembly section. This maintains the ball joint's assembly position under alternating push-pull loads and ensures continuous load transfer to the hinge wing and base body via the integrated rocker arm hinge. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present application and, together with the specification, serve to explain the technical solutions of the present application.

[0031] Figure 1 This is an exploded structural diagram of the foot universal joint base, universal joint and its limiting components in one embodiment of this application.

[0032] Figure 2 This is a schematic diagram of the assembly structure of the leg universal joint base and the lower leg connector in one embodiment of this application.

[0033] Figure 3 This is a schematic diagram showing the positional relationship of the ball joint relative to the universal joint rotation center in the width and height directions of the foot, according to one embodiment of this application.

[0034] Figure 4 This is a schematic diagram showing the positional relationship of the ball head relative to the universal joint rotation center in the front-rear direction of the foot in one embodiment of this application.

[0035] Figure 5 This is a three-dimensional structural diagram of the foot universal joint base in one embodiment of this application.

[0036] Figure 6 This is a top view schematic diagram of four candidate hinge positions in one embodiment of this application.

[0037] Figure 7(a) is a top view of an embodiment of this application in which the first rocker hinge rod and the second rocker hinge rod are respectively disposed on the right and left sides of the rear hinge wing.

[0038] Figure 7(b) is a top view of an embodiment of this application in which the first rocker hinge rod and the second rocker hinge rod are respectively disposed on the right and left sides of the front hinge wing.

[0039] Figure 7(c) is a top view of an embodiment of this application in which the first rocker hinge rod is located on the right side of the front hinge wing and the second rocker hinge rod is located on the left side of the rear hinge wing.

[0040] Figure 7(d) is a top view of an embodiment of this application in which the first rocker hinge rod is located on the right side of the rear hinge wing and the second rocker hinge rod is located on the left side of the front hinge wing.

[0041] Figure 8 This is a schematic diagram of the overall structure of a small humanoid robot in one embodiment of this application.

[0042] Explanation of reference numerals in the attached drawings: 600, Small humanoid robot; 601, Body; 602, Upper limb; 603, Leg; 604, Foot; 10, Foot universal joint base; 11, Base body; 12, Front hinge wing; 13, Rear hinge wing; 14, Universal joint mounting space; 15, First rocker arm hinge rod; 16, Second rocker arm hinge rod; 17, Main body section; 18, Assembly section; 20, Universal joint; 21, First rotation axis; 22, Second rotation axis; 23, Intersection point; 30, Lower leg connection. Components; 40, footplate; 50, first rocker arm; 60, second rocker arm; 70, first ball joint; 80, second ball joint; 90, fastener; 100, hinge seat; 102, retaining ring; 110, bearing; 400, foot support structure; P, candidate hinge position; X, distance from the center of the ball joint to a vertical plane passing through the intersection and extending along the front-back direction of the foot; Y, distance from the center of the ball joint to a vertical plane passing through the intersection and extending along the width direction of the foot; Z, distance from the center of the ball joint to a horizontal plane passing through the intersection. Detailed Implementation

[0043] The embodiments of this application will now be described with reference to the accompanying drawings. The following embodiments are intended to clarify the structural relationships and working principles of this application and should not be construed as limiting the scope of protection of this application. The same reference numerals in the drawings denote the same or corresponding components. The drawings are primarily used to illustrate the assembly and positional relationships between the components and are not necessarily drawn to scale.

[0044] The directional terms "front," "back," "left," "right," "width direction," and "height direction" used in this application are based on the state of the small humanoid robot 600 standing normally with its footplate 40 in contact with the support surface. Specifically, the front-back direction of the foot corresponds to the length direction of the footplate 40, and the width direction of the foot corresponds to the left-right direction of the footplate 40. When the robot or the ankle assembly is in other postures, each direction changes with its overall posture.

[0045] The terms "first," "second," etc., are used only to distinguish components with the same or similar names and do not indicate the number, order, or importance of the components. The terms "including" and "having" indicate open inclusion, meaning that in addition to the explicitly listed components, other components required to achieve ankle actuation, detection, sealing, or connection may be included.

[0046] In this application, "integral formation" means that there is no detachable fastening interface between the corresponding parts for transmitting rocker arm loads, and that they can be formed from the same blank or obtained through a molding process that can form a continuous integral structure. Positional relationships such as "coincident center axes" and "located at the same height" allow for manufacturing and assembly tolerances.

[0047] Please refer to Figures 1 to 6Figures 7(a) to 7(d) show an embodiment of this application providing a foot universal joint base 10, which is installed on the ankle of a small humanoid robot 600 to support the universal joint 20 and provide a movable connection position for the lower ends of the first rocker arm 50 and the second rocker arm 60.

[0048] In one embodiment, please refer to Figure 1 , Figure 2 and Figure 5 The foot universal joint base 10 mainly includes a base body 11, a front hinge wing 12, and a rear hinge wing 13. During assembly, the base body 11 is positioned entirely above the foot plate 40. The front hinge wing 12 and the rear hinge wing 13 extend upward from the base body 11 and are spaced apart along the front-to-back direction of the foot. The gap between the two hinge wings forms a universal joint mounting space 14. After assembly, the lower ends of the universal joint 20 and the lower leg connector 30 are at least partially located within this universal joint mounting space 14.

[0049] In one embodiment, please refer to Figure 6 The front articulated wing 12 and the rear articulated wing 13 each have side portions located on the left and right sides in the width direction of the foot. The left side of the front articulated wing 12, the right side of the front articulated wing 12, the left side of the rear articulated wing 13, and the right side of the rear articulated wing 13 constitute four candidate articulation positions. These four candidate articulation positions are located in... Figure 6 All are represented by P. In a specific embodiment, one position is selected from two candidate hinge positions on the left and one position is selected from two candidate hinge positions on the right. A first rocker hinge rod 15 and a second rocker hinge rod 16 are integrally formed at the two selected positions, respectively. The first rocker hinge rod 15 and the second rocker hinge rod 16 extend outward along the width direction of the foot, so that the corresponding ball heads are located on the left and right sides of the foot universal joint base 10.

[0050] As shown in Figures 7(a) to 7(d), there are four combinations of candidate hinge positions corresponding to the two rocker hinge rods: In Figure 7(a), the first rocker hinge rod 15 and the second rocker hinge rod 16 are respectively located on the right and left sides of the rear hinge wing 13; In Figure 7(b), the first rocker hinge rod 15 and the second rocker hinge rod 16 are respectively located on the right and left sides of the front hinge wing 12; In Figure 7(c), the first rocker hinge rod 15 is located on the right side of the front hinge wing 12, and the second rocker hinge rod 16 is located on the left side of the rear hinge wing 13; In Figure 7(d), the first rocker hinge rod 15 is located on the right side of the rear hinge wing 13, and the second rocker hinge rod 16 is located on the left side of the front hinge wing 12. Figures 1 to 5 The embodiment shown adopts the arrangement shown in Figure 7(a).

[0051] The four candidate hinge positions are used to accommodate different front and rear rocker arm arrangements, but this does not mean that rocker arm hinge rods need to be installed at all four positions. In each embodiment, the first rocker arm hinge rod 15 and the second rocker arm hinge rod 16 are only provided at the two candidate hinge positions located on opposite sides in the foot width direction.

[0052] In one embodiment, the first rocker hinge rod 15 and the second rocker hinge rod 16 are directly formed on the front hinge wing 12 or the rear hinge wing 13. When the first rocker 50 or the second rocker 60 pushes or pulls the corresponding ball head, the load is sequentially transmitted from the ball head to the corresponding rocker hinge rod, the hinge wing, and the base body 11. No independent rocker support is needed between the ball head and the hinge wing, thereby reducing assembly errors, loosening noise, and space occupation caused by independent rocker supports and their fasteners.

[0053] In one embodiment, please refer to Figure 1 , Figure 2 and Figure 5 The first rocker arm hinge 15 and the second rocker arm hinge 16 are respectively formed on the left and right sides of the rear hinge wing 13 and extend outward along the width of the foot. The two rocker arm hinges are supported by the same rear hinge wing 13. The front hinge wing 12 and the rear hinge wing 13 jointly support the universal joint 20. The first rocker arm 50 and the second rocker arm 60 are located on the left and right sides of the ankle assembly, respectively.

[0054] In one embodiment, the central axes of the first rocker hinge rod 15 and the second rocker hinge rod 16 coincide. Thus, the two rocker hinge rods form a common axis extending through the rear hinge wing 13 in the foot width direction, allowing the first ball joint 70 and the second ball joint 80 mounted on both sides to have the same height reference. This relationship also facilitates the unified determination of the positions of the two rocker hinge rods during the machining of the rear hinge wing 13.

[0055] In one embodiment, the base body 11, the front hinge wing 12, the rear hinge wing 13, the first rocker hinge rod 15, and the second rocker hinge rod 16 can be integrally formed structures, such as by metal casting or integral machining. Figure 5 The shape of the integrated structure is shown. Since the root of the rocker arm is continuously connected to the rear hinge wing 13, the bending and shear loads generated at the ball head can be directly transmitted to the rear hinge wing 13, and the root of the rocker arm does not need to be fixed to the rear hinge wing 13 by screws or nuts.

[0056] In one embodiment, please refer to Figure 1 and Figure 5Both the first rocker arm hinge 15 and the second rocker arm hinge 16 include a main body section 17 and an assembly section 18. One end of the main body section 17 is integrally connected to the rear hinge wing 13, and the assembly section 18 is located at the end of the main body section 17 away from the rear hinge wing 13. The outer diameter of the assembly section 18 is smaller than the outer diameter of the main body section 17, forming an annular step at the connection between the two. The main body section 17 and the assembly section 18 are both components of the corresponding rocker arm hinge, while the first rocker arm hinge 15 and the second rocker arm hinge 16 are both components of the universal joint base 10.

[0057] In one embodiment, the first ball head 70 and the second ball head 80 are respectively provided with through holes passing through the center of the ball. During assembly, the first ball head 70 is sleeved on the assembly section 18 of the first rocker arm hinge 15, and the second ball head 80 is sleeved on the assembly section 18 of the second rocker arm hinge 16. The side of the ball head facing the rear hinge wing 13 is positioned by a step between the main body section 17 and the assembly section 18, and a fastener 90 is installed at the outer end of the assembly section 18 to prevent the ball head from dislodging outward along the width direction of the foot.

[0058] In one embodiment, the fastener 90 may be a screw, nut, or other axial limiting member adapted to the end structure of the assembly section 18. The specific form of the fastener 90 may be selected depending on whether the assembly section 18 has an internal thread structure, an external thread structure, or a snap-fit ​​structure. Regardless of the form, the fastener 90 is located on the outside of the ball head and engages with the step on one side of the main body section 17 to lock the axial position of the ball head.

[0059] In one embodiment, the universal joint 20 may include a universal joint seat, a bearing, an inner pressure ring, and a fastener 90 for axial positioning. The universal joint seat is located between the front hinge wing 12 and the rear hinge wing 13, and the bearing is disposed between the universal joint seat and the corresponding connection part, allowing the universal joint seat to rotate about the corresponding rotation axis. The inner pressure ring and the fastener 90 are used to restrict the movement of the bearing or the universal joint seat along the rotation axis.

[0060] To avoid ambiguity in the interpretation of reference numerals, the fastener 90 in this application is a general reference for axial limiting components; the fastener 90 located at the outer end of the ball joint assembly section and the fastener 90 located at the universal joint seat or bearing may be the same or different specific fasteners depending on the assembly position, and their common function is axial limiting. Reference numeral 90 does not limit the two to be the same entity.

[0061] In one embodiment, the universal joint 20 defines a first rotation axis 21 and a second rotation axis 22. The two rotation axes intersect at an intersection point 23, which constitutes the rotation center of the universal joint 20. The first rotation axis 21 and the second rotation axis 22 can respectively correspond to two swing directions of the foot relative to the lower leg connector 30, enabling the foot 604 to perform two degrees of freedom of movement relative to the leg 603.

[0062] Please refer to Figures 1 to 2 One embodiment of this application also provides a foot and ankle assembly. The foot and ankle assembly includes a foot plate 40, a lower leg connector 30, a universal joint 20, a first rocker arm 50, a second rocker arm 60, a first ball joint 70, a second ball joint 80, and a foot universal joint base 10. The lower leg connector 30 is located above the foot plate 40, with its lower end extending into the universal joint mounting space 14, and is connected to the foot universal joint base 10 via the universal joint 20.

[0063] In one embodiment, a first ball joint 70 is mounted on a first rocker arm hinge 15, and a second ball joint 80 is mounted on a second rocker arm hinge 16. The lower end of the first rocker arm 50 is ball-jointed to the first ball joint 70, and the lower end of the second rocker arm 60 is ball-jointed to the second ball joint 80. The upper ends of the first rocker arm 50 and the second rocker arm 60 can be connected to a drive mechanism respectively mounted on the leg 603 or the lower leg connector 30. The drive mechanism applies a pushing or pulling force to the foot universal joint base 10 through the two rockers.

[0064] In one embodiment, the movement of the first rocker arm 50 and the second rocker arm 60 can be controlled according to the desired posture of the foot. When the two rocker arms produce a coordinated displacement in the same direction, their forces can form a resultant torque around one of the rotation axes on the foot universal joint base 10; when the two rocker arms produce a differential displacement, a resultant torque can be formed around the other rotation axis. The two rocker arms can also move simultaneously with different displacement amounts, causing the foot 604 to produce a composite movement around the first rotation axis 21 and the second rotation axis 22.

[0065] In one embodiment, the foot universal joint base 10, universal joint 20, and lower leg connector 30 can be pre-assembled into an ankle pre-assembly module. When assembling the ankle pre-assembly module, the bearing, inner pressure ring, and universal joint seat can be first installed on the foot universal joint base 10, and then the lower leg connector 30 can be connected to the universal joint 20. After the ankle pre-assembly module is assembled, the rotating components and axial limiting components of the universal joint 20 remain on the foot universal joint base 10.

[0066] In one embodiment, the base body 11 is provided with a foot plate connecting part, which corresponds to the mounting position on the foot plate 40. After the ankle pre-assembly module is completed, the foot universal joint base 10 is fixed to the foot plate 40 through the foot plate connecting part, so that the lower leg connector 30, universal joint 20 and foot universal joint base 10 can be integrally installed into the foot support structure 400. The foot plate connecting part can adopt a mounting hole, positioning hole, positioning surface or a connection structure that mates with fasteners.

[0067] In one embodiment, after adopting the pre-installed ankle module, the bearings and inner pressure rings on both sides of the universal joint 20 can be installed while the foot universal joint base 10 is separated from the foot plate 40. The assembler can operate the corresponding fasteners 90 from the outside of the foot universal joint base 10 and check whether the universal joint 20 rotates smoothly and whether the axial limit is in place before installing it onto the foot plate 40. When maintenance is required, the connection at the foot plate connection can be disconnected, and the entire pre-installed ankle module can be removed.

[0068] In one embodiment, please refer to Figure 3 and Figure 4 The first ball head 70 and the second ball head 80 have vertical and horizontal distances relative to the intersection point 23. A vertical plane passing through the intersection point 23 and extending along the front-back direction of the foot is used as the first reference plane, a vertical plane passing through the intersection point 23 and extending along the width direction of the foot is used as the second reference plane, and a horizontal plane passing through the intersection point 23 is used as the third reference plane.

[0069] In one embodiment, the centers of the first ball joint 70 and the second ball joint 80 are symmetrical about a first reference plane, and the line connecting the two centers extends along the width direction of the foot. Both centers are located on the same side of the second reference plane and at the same height. Thus, the two ball joints have the same front-to-back offset and height offset relative to the rotation center of the universal joint 20, and are symmetrically distributed in the left-to-right direction.

[0070] In one embodiment, the distance from each sphere center to the first reference plane is denoted as X, the distance from each sphere center to the second reference plane is denoted as Y, and the distance from each sphere center to the third reference plane is denoted as Z. Figure 3 X and Z are shown. Figure 4 The diagram shows Y. X represents the lateral lever arm of the ball joint relative to the center of rotation of the universal joint, Y represents the longitudinal lever arm of the ball joint relative to the center of rotation of the universal joint, and Z represents the height difference between the ball joint and the center of rotation of the universal joint.

[0071] In one embodiment, Z is less than X and less than Y. That is, the height difference between the ball joint and the universal joint rotation center is less than its offset distance in the width direction and the fore-and-aft direction of the foot. This arrangement gives the two rockers horizontal lever arms on both sides of the ankle for generating driving torque, while keeping the lower ends of the rockers within a height range close to the universal joint rotation center, avoiding increasing the height of the ankle structure due to the ball joint being too high.

[0072] In one embodiment, X is one-third to one-half of the maximum dimension of the footplate 40 in the foot width direction. This proportion places the first ball head 70 and the second ball head 80 close to the left and right sides of the footplate 40, respectively, to obtain sufficient lateral lever arm. X is not greater than one-half of the maximum dimension of the footplate 40 in the foot width direction, so that the center of the ball head can be kept within the width range of the footplate 40.

[0073] In an optional embodiment, the ratio of X to the maximum width of the footplate 40 can be 1 / 3, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 2 / 5, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, or 1 / 2, or any value between the aforementioned adjacent values. For example, when the maximum width of the footplate 40 is 90 mm, X can be 30 mm, 36 mm, or 45 mm; when the maximum width of the footplate 40 is 100 mm, X can be 40 mm or 50 mm.

[0074] In one embodiment, Y is 1 / 5 to 1 / 4 of the maximum dimension of the footplate 40 in the anteroposterior direction of the foot. This proportion creates an appropriate anteroposterior distance between the ball head and the intersection point 23, which preserves the anteroposterior lever arm required for foot swing and allows for installation space between the ball head and the front or rear end of the footplate 40.

[0075] In an optional embodiment, the ratio of Y to the maximum front-to-back dimension of the footplate 40 can be 1 / 5, 0.21, 0.22, 0.23, 0.24, or 1 / 4, or any value between the aforementioned adjacent values. For example, when the maximum front-to-back dimension of the footplate 40 is 200 mm, Y can be 40 mm, 44 mm, or 50 mm.

[0076] Please refer to Figure 1 The lower ends of the first rocker arm 50 and the second rocker arm 60 are respectively provided with hinge seats 100, and bearings 110 are installed inside the hinge seats 100. The first ball head 70 and the second ball head 80 are respectively assembled in the corresponding bearings 110. The spherical part of the ball head cooperates with the bearing 110, so that the first rocker arm 50 and the second rocker arm 60 can rotate relative to the corresponding ball head to adapt to the change of the included angle between the rocker arm and the rocker arm hinge during the movement of the ankle component.

[0077] In one embodiment, a retaining ring 102 is provided on the side of the hinge seat 100 facing the corresponding rocker arm hinge rod. The retaining ring 102 is disposed on the side of the bearing 110 facing the rocker arm hinge rod and is used to axially limit the bearing 110. The inner hole of the retaining ring 102 allows the assembly section 18 to pass through. The first ball head 70 and the second ball head 80 are respectively sleeved on the corresponding assembly section 18. The fastener 90 installed at the outer end of the assembly section 18 is used to prevent the corresponding ball head from dislodging outward along the assembly section 18. Thus, the bearing 110 remains mounted relative to the hinge seat 100, the ball head remains axially limited relative to the rocker arm hinge rod, and the rocker arm can swing relative to the rocker arm hinge rod through the cooperation between the bearing 110 and the ball head.

[0078] When assembling the ball joint at the lower end of the rocker arm, first install the bearing 110 onto the hinge seat 100, then align the lower end of the corresponding rocker arm with the rocker arm hinge rod, place the corresponding ball head onto the assembly section 18 and insert the bearing 110, and finally install the fastener 90. After the fastener 90 is installed in place, the ball head is restricted along the axial direction of the assembly section 18, while the bearing 110 allows the rocker arm to change its angle relative to the ball head.

[0079] The overall assembly of the ankle assembly can be performed in the following order: First, install the universal joint 20 between the front hinge wing 12 and the rear hinge wing 13, and complete the assembly of the bearing, inner pressure ring, and fastener 90; then connect the lower leg connector 30 to the universal joint 20 to form the ankle pre-assembly module; subsequently, fix the ankle pre-assembly module to the footplate 40; finally, complete the ball joint connection between the first ball joint 70, the second ball joint 80, the first rocker arm 50, and the second rocker arm 60. In actual assembly, the order of assembly of the ball joint parts and the footplate 40 can be adjusted according to the operating space.

[0080] Please refer to Figure 8 An embodiment of this application also provides a small humanoid robot 600. The small humanoid robot 600 includes a body 601, an upper limb 602 connected to the body 601, a leg 603 connected to the body 601, and a foot 604 disposed at the lower end of the leg 603. The foot 604 includes the aforementioned ankle assembly, a lower leg connector 30 is connected to the lower end of the leg 603, and a foot plate 40 constitutes a foot support structure 400 in contact with the ground.

[0081] In one embodiment, with the small humanoid robot 600 standing normally and its footplate 40 in contact with the horizontal support surface, the vertical distance from the horizontal support surface to the highest point of the small humanoid robot 600 is taken as the overall height. This overall height can be 0.6 meters, 0.7 meters, 0.8 meters, 0.9 meters, 1.0 meters, 1.1 meters, or 1.2 meters, or any value between these adjacent values. For example, in one specific embodiment, the overall height is 0.8 meters, and in another specific embodiment, the overall height is 1.0 meter; all embodiments can use the aforementioned ankle assembly.

[0082] When the robot is working, the legs 603 transmit support loads to the universal joint 20 and the foot universal joint base 10 through the lower leg connector 30, while the first rocker arm 50 and the second rocker arm 60 apply attitude adjustment loads to the foot universal joint base 10 through the first ball joint 70 and the second ball joint 80. Since the two rocker arm hinges are integrally formed with the hinge wing, the attitude adjustment load and the universal joint support load can converge within the foot universal joint base 10 and be transmitted to the foot plate 40 by the base body 11.

[0083] In the illustrated embodiment, the first rocker hinge rod 15 and the second rocker hinge rod 16 are positioned on opposite sides of the rear hinge wing 13. However, if the two rocker hinge rods are located on opposite sides of the foot width direction, one or both rocker hinge rods can also be positioned on the front hinge wing 12 depending on the rocker arrangement. The specific structure of the universal joint 20, the connection form of the foot plate connection, and the form of the fastener 90 can also be selected according to the robot size and load.

[0084] The above embodiments are used to illustrate the technical solutions of this application, and are not intended to limit this application. Those skilled in the art can make adjustments or substitutions to the specific shape, connection method, and assembly sequence of each component without departing from the concept of this application, and such adjustments or substitutions should still fall within the scope defined by the claims.

Claims

1. A foot universal joint base for a small humanoid robot, having a foot in the anteroposterior direction and a foot in the width direction, characterized in that, It includes a base body and a front hinge wing and a rear hinge wing that are spaced apart on the base body along the front-rear direction of the foot, and a universal joint mounting space for mounting a universal joint is formed between the front hinge wing and the rear hinge wing. The front hinge wing and the rear hinge wing each have side portions located on opposite sides in the width direction of the foot, and the two side portions of the front hinge wing and the two side portions of the rear hinge wing constitute four candidate hinge positions; Two of the four candidate hinge positions are located on opposite sides of the foot width direction, and each has an integrally formed first rocker hinge rod and second rocker hinge rod. The first rocker hinge rod and the second rocker hinge rod extend outward from the corresponding candidate hinge positions along the foot width direction, and are used to install ball heads that are connected to the first rocker and the second rocker ball joint, respectively.

2. The foot universal joint base according to claim 1, characterized in that, The two sides of the rear hinge wing correspond to two of the four candidate hinge positions, respectively. The central axes of the first rocker hinge rod and the second rocker hinge rod coincide, and their common central axis runs through the rear hinge wing along the width direction of the foot. The two ball heads mounted on both have the same height reference.

3. The foot universal joint base according to claim 1, characterized in that, The front hinge wing is located in front of the first rocker hinge rod and the second rocker hinge rod, and the universal joint mounting space is staggered from the two ball joints along the front-rear direction of the foot.

4. The foot universal joint base according to claim 1, characterized in that, The integrated structure comprising the base body, the front hinge wing, the rear hinge wing, the first rocker hinge rod, and the second rocker hinge rod is formed by metal casting or integral machining.

5. The foot universal joint base according to claim 1, characterized in that, There is no detachable fastening interface for transmitting rocker load between the first rocker hinge rod and the second rocker hinge rod and the rear hinge wing.

6. The foot universal joint base according to claim 1, characterized in that, The first rocker arm hinge and the second rocker arm hinge each include a main body section and an assembly section connected to the outer end of the main body section. The outer diameter of the assembly section is smaller than the outer diameter of the main body section. An annular step is formed between the main body section and the assembly section. The outer end of the assembly section is provided with a threaded structure or a snap-fit ​​structure.

7. The foot universal joint base according to claim 6, characterized in that, The foot universal joint base also includes a first ball head and a second ball head respectively installed on the first rocker hinge rod and the second rocker hinge rod. The first ball head and the second ball head are respectively provided with through holes for the corresponding assembly sections to pass through. The outer end of each assembly section is provided with a fastener for restricting the corresponding ball head from dislodging outward along the assembly section.

8. An ankle assembly for a small humanoid robot, characterized in that, It includes a foot plate, a lower leg connector, a universal joint, a first rocker arm, a second rocker arm, a first ball joint, a second ball joint, and a foot universal joint base as described in any one of claims 1 to 7; The universal joint is disposed in the universal joint installation space and connected to the lower leg connector. The foot universal joint base, the universal joint, and the lower leg connector together form an ankle pre-installed module that can be installed as a whole on the foot plate. The foot universal joint base is detachably connected to the foot plate. The first ball joint is mounted on the first rocker arm hinge, and the second ball joint is mounted on the second rocker arm hinge. The first rocker arm is connected to the first ball joint ball joint, and the second rocker arm is connected to the second ball joint ball joint.

9. The ankle assembly according to claim 8, characterized in that, The base body is provided with a foot plate connecting part, and the ankle pre-installed module is detachably connected to the foot plate through the foot plate connecting part.

10. The ankle assembly according to claim 9, characterized in that, The lower leg connector extends at least partially into the universal joint mounting space, and the universal joint connects the lower leg connector to the foot universal joint base so that the lower leg connector can rotate relative to the foot universal joint base about a first rotation axis and a second rotation axis defined by the universal joint.

11. The ankle assembly according to claim 8, characterized in that, The first rocker hinge rod and the second rocker hinge rod each include a main body section and an assembly section connected to the outer end of the main body section. The first ball head and the second ball head are respectively provided with through holes that pass through the center of the ball and allow the corresponding assembly section to pass through. The two centers of the ball are located on the common central axis of the first rocker hinge rod and the second rocker hinge rod.

12. The ankle assembly according to claim 8, characterized in that, The universal joint defines a first rotation axis and a second rotation axis that intersect at a point, and the centers of the first ball joint and the second ball joint are symmetrical about a vertical plane that passes through the intersection point and extends along the front-rear direction of the foot.

13. The ankle assembly according to claim 12, characterized in that, The line connecting the centers of the first ball head and the second ball head extends along the width direction of the foot. The two centers of the ball are located on the same side of a vertical plane that passes through the intersection point and extends along the width direction of the foot in the front-back direction of the foot, and the two centers of the ball are at the same height.

14. The ankle assembly according to claim 13, characterized in that, Let X be the distance from each ball center to a vertical plane that passes through the intersection point and extends along the front-back direction of the foot, let Y be the distance from each ball center to a vertical plane that passes through the intersection point and extends along the width direction of the foot, and let Z be the distance from each ball center to a horizontal plane that passes through the intersection point. Let Z be less than X and less than Y.

15. The ankle assembly according to claim 14, characterized in that, X is 1 / 3 to 1 / 2 of the maximum dimension of the footplate in the width direction of the foot.

16. The ankle assembly according to claim 15, characterized in that, The Y is 1 / 5 to 1 / 4 of the maximum dimension of the footplate in the front-back direction of the foot.

17. The ankle assembly according to claim 8, characterized in that, The lower ends of the first rocker and the second rocker are respectively provided with hinge seats, and bearings are installed in the hinge seats. The first ball head and the second ball head are respectively rotatably engaged with the corresponding bearings so that the first rocker and the second rocker are respectively connected to the corresponding ball head ball hinges.

18. The ankle assembly according to claim 17, characterized in that, The hinge seat has a retaining ring on the side facing the corresponding rocker arm hinge rod. The retaining ring is located on the side of the corresponding bearing facing the rocker arm hinge rod to axially limit the bearing. The outer end of the corresponding rocker arm hinge rod is provided with a fastener to prevent the corresponding ball head from dislodging outward along the rocker arm hinge rod.

19. A small humanoid robot, characterized in that, The invention includes a fuselage, a leg connected to the fuselage, and an ankle assembly connected to the leg as described in any one of claims 8 to 18. The lower leg connector is connected to the lower end of the leg, and the foot plate constitutes the foot support structure of the small humanoid robot.

20. The small humanoid robot according to claim 19, characterized in that, When the small humanoid robot is standing normally and its feet are in contact with the horizontal support surface, the vertical distance from the horizontal support surface to the highest point of the small humanoid robot is 0.6 meters to 1.2 meters.

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