A deformable robotic wheel-foot mechanism

Abstract

The application relates to a deformable robot wheel-foot mechanism, and relates to a wheel-foot mechanism. The application is used to solve the problem of instability in walking on rough road surfaces of the existing wheel-leg conversion device. The application comprises a deformable hub driving wheel (1) and a lower leg (2), the deformable hub driving wheel (1) being an ankle joint driving component of a wheel-foot robot, the deformable hub driving wheel (1) being rotatably installed at the lower part of the lower leg (2), the ankle joint driving component pushing a linkage system through six hydraulic cylinders, controlling the deformation of the arc-shaped hub into a circle or a triangle, and each hub hydraulic cylinder piston (1-2) respectively pushing the hub arc linkages (1-8) in each two groups of adjacent hub arc assemblies to move in the corresponding direction, so that the geometric shape of the hub is changed. The application is used for the walking of robots in different road surface environments.

Description

TECHNICAL FIELD

[0001] The present application relates to a robot wheel-foot mechanism, in particular to a deformable robot wheel-foot mechanism, and more particularly to a wheel hub structure capable of realizing wheel-foot switching deformation. BACKGROUND

[0002] Currently, the mobile part of traditional robots mostly adopts wheel type or foot type design, each having advantages and disadvantages. The wheel type robot moves fast on flat ground, but is easily limited in complex terrain; the foot type robot can adapt to various terrains, but has low speed and efficiency. The wheel-foot robot combines the advantages of the wheel type and foot type robots, can move flexibly on different terrains, and improves the motion ability.

[0003] Most of the current wheel-foot robots adopt fixed shape wheel hubs for movement, which can provide high speed on flat ground, but face great obstacle challenge in complex terrain. There is a lack of scheme capable of dynamically adjusting the shape of the wheel hub to adapt to different terrain requirements in the prior art.

[0004] However, with the development of modern robot technology, the flexibility and adaptability of robots are increasingly required in the fields of rescue, exploration, logistics, etc. The traditional wheel-legged robot cannot fully meet the needs of the development of the times, which promotes the research on the leg mechanism design of new wheel-legged robots, especially the research on the wheel hub structure capable of realizing flexible switching of wheel-foot of robots that can cope with extremely complex environments.

[0005] For example: the invention patent with the patent name of a wheel-leg conversion device and the authorization announcement number of CN109398520B, which includes a wheel thigh, a wheel calf and a wheel-leg conversion driving device; the wheel thigh is a left-right symmetrical structure, the middle part of which is provided with a wheel-leg conversion driving device mounting groove, and the lower part of which is provided with a pin shaft three mounting hole one symmetrically on the left and right sides, which is used for connecting with the wheel calf, and the wheel calf is hingedly installed on the wheel thigh through the pin shaft three; two groups of wheel-leg conversion driving link assemblies are symmetrically arranged on the left and right sides of the wheel thigh, which are used for connecting the wheel thigh, the wheel calf and the wheel-leg conversion driving device to realize the contraction of the wheel-leg into a wheel shape or the expansion into a leg shape; through this way, the conversion of the wheel shape structure and the leg shape structure can be realized, when the wheel shape structure is deformed, fast walking on flat road surface can be realized, the diameter of the wheel shape structure is large, and the road surface adaptability is strong; when the leg shape structure is deformed, fast walking on rugged road surface can be realized, the leg length is long, and the obstacle crossing ability is strong. The deformation driving device adopts a multi-link mechanism, which is simple in structure and easy to manufacture.

[0006] However, the wheel-leg conversion device has the problem of unstable walking when walking on rugged road surface, because the shape of the wheel-leg changes greatly when it is changed into a leg shape structure, and the contact area with the ground is small.

[0007] In summary, the existing wheel-leg conversion device has the problem of unstable walking when walking on rough road surface. SUMMARY

[0008] The present application aims to solve the problem of unstable walking when the existing wheel-leg conversion device walks on rough road surface. Furthermore, a deformable robot wheel-foot mechanism is provided.

[0009] The technical solution of the present application is: a deformable robot wheel-foot mechanism includes a deformable hub drive wheel and a lower leg, the deformable hub drive wheel is an ankle joint driving component of the wheel-foot robot, the deformable hub drive wheel is rotatably installed at the lower part of the lower leg, the ankle joint driving component drives the linkage system through six hydraulic cylinders, controls the deformation of the arc-shaped hub into a circle or a triangle, and each hub hydraulic cylinder piston respectively drives the hub arc linkage in each two groups of adjacent hub arc assemblies to move in the corresponding direction, thereby realizing the change of the geometry of the hub.

[0010] Further, the deformable hub drive wheel includes a hub center wheel, six hub hydraulic cylinder pistons, a motor hub transmission shaft, a hub arc, a hub arc linkage, a hub arc linkage shaft and a flat tire; the motor hub transmission shaft is rotatably inserted into the hub center wheel, the six hub hydraulic cylinder pistons are installed on the hub center wheel in a radial manner with the hub center wheel as the center, the extension end of each hub hydraulic cylinder piston is connected with the connection part of adjacent two hub arcs, the adjacent two hub arcs form a hub arc assembly, the adjacent two hub arc assemblies are rotatably connected through the hub arc linkage and the hub arc linkage shaft, the flat tire is installed on the hub arc assembly, and the flat tire adjusts with the change of the shape of the hub; a plurality of hub arc assemblies form an arc-shaped hub.

[0011] Still further, the deformable hub drive wheel further includes a drive wheel oil running joint and two ankle joint hub bearings, the drive wheel oil running joint is installed between the hub center wheel and the motor hub transmission shaft, and the two ankle joint hub bearings are respectively located on the left and right sides of the drive wheel oil running joint.

[0012] Preferably, the motor hub transmission shaft is a stepped gear shaft.

[0013] Further, the deformable hub drive wheel further includes a plurality of hydraulic cylinder guide sleeves, one hydraulic cylinder guide sleeve is sleeved on the extension end of each hub hydraulic cylinder piston.

[0014] Still further, the lower leg includes a 3D metal printed lower leg skeleton, an ankle joint protection shell and a motor drive assembly, the ankle joint protection shell is installed at the lower part of the 3D metal printed lower leg skeleton, and the motor drive assembly is embedded in the ankle joint protection shell and transmits driving power and torque to the motor hub transmission shaft.

[0015] Furthermore, the motor drive assembly includes a motor end cover, a drive wheel motor gear train, a drive wheel motor rotor disc, a drive wheel motor stator coil, a drive wheel motor rotor housing, an inner bearing at the motor output end, a wheel axle end cover, an outer bearing at the motor output end, and a planetary gear output flange. The drive wheel motor stator coil is installed inside the drive wheel motor rotor housing, the drive wheel motor rotor disc is installed on one side of the drive wheel motor rotor housing, the drive wheel motor gear train is installed inside the drive wheel motor stator coil, the planetary gear output flange is installed on the drive wheel motor gear train, the inner and outer bearings at the motor output end are installed on the outer side of the planetary gear output flange, and the wheel axle end cover and the motor end cover are respectively installed on the two side end faces of the ankle joint protective shell.

[0016] Furthermore, the lower leg also includes an inner knee joint bushing, a pressure sensor, and a knee joint hydraulic servo valve; the inner knee joint bushing is horizontally embedded in the upper part of the 3D metal-printed lower leg skeleton, and the pressure sensor and the knee joint hydraulic servo valve are installed in the middle of the 3D metal-printed lower leg skeleton.

[0017] Furthermore, the lower leg also includes an encoder and an encoder end cap, with the encoder mounted inside the ankle joint protective shell via the encoder end cap.

[0018] Preferably, the drive wheel motor gear system includes an internal gear ring, multiple planetary gears, a motor drive shaft, a planetary gear output shaft, a deep groove ball bearing, an 8mm motor drive shaft shoulder retaining ring, a 7mm motor drive shaft shoulder retaining ring, a motor hub drive shaft elastic retaining ring, and a planetary gear output shaft elastic retaining ring. The internal gear ring is installed inside the drive wheel motor rotor housing, the motor drive shaft is installed inside the sun gear inside the internal gear ring, the multiple planetary gears, the sun gear, and the internal gear ring mesh with each other, the planetary gear output shaft passes through the planetary gears, the deep groove ball bearing is fitted on the planetary gear output shaft, the planetary gear output shaft elastic retaining ring is installed at the end of the planetary gear output shaft, the motor hub drive shaft elastic retaining ring and the 8mm motor drive shaft shoulder retaining ring are installed at one end of the motor drive shaft, and the 7mm motor drive shaft shoulder retaining ring is installed at the other end of the motor drive shaft.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. This invention provides a deformable hub structure capable of switching the hub shape at the end of the lower leg according to terrain conditions. As a deformable motion actuator for a wheeled robot, its circular hub structure ensures the robot's movement speed on flat ground, while its triangular wheel structure ensures stronger obstacle-crossing ability and terrain adaptability than traditional wheeled robots in complex environments, and provides a larger contact area with the ground for greater stability during walking. Simultaneously, the lower leg employs a derivative-designed lightweight skeleton structure, ensuring structural strength while reducing the weight of the robot's lower leg.

[0021] 2. The shape of this invention is variable: the hub can switch between a circle and a triangle. The circular hub is suitable for flat ground and provides higher speed; the triangular hub is suitable for complex terrain and enhances obstacle-crossing ability.

[0022] 3. The invention is simple to operate: the shape of the wheel hub can be adjusted by controlling the mechanism (mainly referring to the extension and retraction of the piston 1-2 of the wheel hub hydraulic cylinder), which can freely switch in different environments without replacing the wheel hub or making complicated adjustments.

[0023] 4. This invention has the function of high efficiency and energy saving: through the optimized design of the wheel hub shape, the circular wheel hub can reduce rolling resistance and improve the robot's driving efficiency on flat ground; the triangular wheel hub can improve obstacle crossing ability and ensure the robot's stability and passability in rugged terrain.

[0024] 5. The leg structure of the wheel-foot mechanism of this invention adopts a 3D-printed metal skeleton structure. The lightweight support structure reduces the overall weight of the robot while improving the strength of the robot's leg structure, ensuring the robot's mobility and endurance in complex environments. This invention optimizes the overall quality of the novel wheel-foot mechanism, enabling the robot to consume less material during manufacturing, reducing costs, and making the robot lighter and more maneuverable.

[0025] 6. Existing wheeled-legged robots typically operate only in a fixed configuration, with a fixed tire contact area and shape. This makes them less effective on rough, obstacle-ridden terrain, often requiring manual intervention or complex control strategies to overcome obstacles. The novel wheel-leg mechanism of this invention allows the robot to maintain speed on flat ground in a circular configuration, while in complex terrain, it can increase obstacle-crossing capability by changing the wheel hub to a triangular shape. This enables the robot to traverse irregular terrain such as rocks, sandpits, and mud without easily getting stuck or losing balance. Compared to traditional wheeled-legged robots, it possesses significantly stronger terrain adaptability.

[0026] 7. This invention analyzes the hydraulic power requirements of the novel hydraulic wheel-foot mechanism, formulates a hydraulic power system design method and specific implementation plan. The hydraulic power system makes full use of the structure of the lower leg, and organically integrates the hydraulic power system with the body of the novel wheel-foot mechanism through a distributed design method to achieve a high degree of integration of the power system. At the same time, the integrated design method maximizes the power density of the core components of the power system.

[0027] 8. The wheeled-legged robot of this invention can be widely used in various fields such as rescue, exploration, logistics, and patrol. In disaster relief scenarios, robots need to cross various obstacles, including rubble, sand pits, and even debris. Traditional wheeled-legged robots usually require manual control or complex mechanical adjustments to overcome obstacles, while the robot of this invention can quickly and seamlessly complete obstacle-crossing tasks through automatic mode switching, ensuring the smooth progress of rescue work.

[0028] Attached Figure Description

[0029] Figure 1 This is an overall structural diagram of the novel wheel-foot mechanism of the present invention;

[0030] Figure 2 This is a structural composition diagram of the deformable hub drive wheel of the present invention;

[0031] Figure 3 This is a diagram showing the composition of the lower leg structure of the present invention;

[0032] Figure 4 This is an exploded view of the drive wheel motor gear system of the present invention;

[0033] Figure 5 This is a motion reference diagram of the present invention;

[0034] Figure 6 This is a schematic diagram of the triangular hub state drive wheel of the present invention;

[0035] Figure 7 This is a schematic diagram of the circular hub state drive wheel of the present invention.

[0036] In the diagram: 1. Deformable hub drive wheel; 1-1. Hub center wheel; 1-2. Hub hydraulic cylinder piston; 1-3. Bare joint hub bearing; 1-4. Bare joint hub bearing retaining ring; 1-5. Motor hub drive shaft; 1-6. Flat tire; 1-7. Hub arc; 1-8. Hub arc connecting rod; 1-9. Hub arc connecting rod shaft; 1-10. Hydraulic cylinder guide sleeve; 1-11. Front end ear; 1-12. Drive wheel oil-feeding joint; 2. Lower leg; 2-1. Knee joint inner bushing; 2-2. 3D metal printed lower leg skeleton; 2-3. Ankle joint protective shell; 2-4. Encoder end cover; 2-5. Motor end cover; 2-6. Drive wheel motor gear system; 261. Internal gear ring; 262. Planetary gear; 263. Electric... 264. Motor drive shaft, planetary gear output shaft, 265. Deep groove ball bearing, 266. 8mm motor drive shaft shoulder retaining ring, 267. 7mm motor drive shaft shoulder retaining ring, 268. Motor hub drive shaft elastic retaining ring, 269. Planetary gear output shaft elastic retaining ring, 2610. Cross-head countersunk screw, 2611. Sun gear, 2-7. Hydraulic pressure sensor, 2-8. Knee joint hydraulic servo valve, 2-9. Drive wheel motor rotor disc, 2-10. Drive wheel motor stator coil, 2-11. Drive wheel motor rotor housing, 2-12. Inner bearing at motor output end, 2-13. Axle end cover, 2-14. Outer bearing at motor output end, 2-15. Planetary gear output flange, 2-16. Encoder. Detailed Implementation

[0037] Specific implementation method one: Combining Figures 1 to 7 This embodiment describes a deformable robot wheel-foot mechanism comprising a deformable hub drive wheel 1 and a lower leg 2. The deformable hub drive wheel 1 is the ankle joint drive component of the wheel-foot robot. The deformable hub drive wheel 1 is rotatably mounted on the lower part of the lower leg 2. The ankle joint drive component controls the arc-shaped hub to deform into a circle or a triangle by pushing a linkage system through six hydraulic cylinders. Each hub hydraulic cylinder piston 1-2 pushes the hub arc connecting rods 1-8 in each pair of adjacent hub arc assemblies, causing them to move in the corresponding direction, thereby changing the geometry of the hub.

[0038] This implementation allows the hub shape to revert to a more compact, standard circle on hard surfaces or smooth surfaces, improving efficiency and speed while reducing energy consumption. When encountering irregular obstacles or undulating terrain, the hub can deform into an angular shape, such as a triangle, enhancing obstacle-crossing ability and ensuring the robot can successfully traverse larger obstacles.

[0039] Specific Implementation Method Two: Combining Figure 1 and Figure 2This embodiment describes a deformable hub drive wheel 1 comprising a hub center wheel 1-1, six hub hydraulic cylinder pistons 1-2, a motor hub drive shaft 1-5, hub arcs 1-7, hub arc connecting rods 1-8, hub arc connecting rod shafts 1-9, and a flat tire 1-6. The motor hub drive shaft 1-5 is rotatably inserted into the hub center wheel 1-1. The six hub hydraulic cylinder pistons 1-2 are radially mounted on the hub center wheel 1-1 with the hub center wheel 1-1 as the center. The telescopic end of each hub hydraulic cylinder piston 1-2 is connected to the connection point of two adjacent hub arcs 1-7. Two adjacent hub arcs 1-7 form a hub arc assembly. Two adjacent hub arc assemblies are rotatably connected by hub arc connecting rods 1-8 and hub arc connecting rod shafts 1-9. The flat tire 1-6 is mounted on the hub arc assembly and adjusts according to the shape of the hub. Multiple hub arc assemblies form an arc-shaped hub.

[0040] With this configuration, the flat tires 1-6 are specially designed to wrap around the rim arc, providing the tire surface with good elasticity and grip. The shape of the flat tires adjusts according to the rim shape, thus ensuring stable ground contact and driving performance. Other components and connections are the same as in Specific Implementation Method One.

[0041] Specific implementation method three: Combining Figure 1 and Figure 2 This embodiment describes a deformable hub drive wheel 1 that further includes a drive wheel oil-feeding joint 1-12 and two ankle joint hub bearings 1-3. The drive wheel oil-feeding joint 1-12 is installed between the hub center wheel 1-1 and the motor hub drive shaft 1-5. The two ankle joint hub bearings 1-3 are located on the left and right sides of the drive wheel oil-feeding joint 1-12, respectively. This arrangement is used to drive the extension and retraction of the hub hydraulic cylinder piston 1-2. Other components and connections are the same as in specific embodiments one or two.

[0042] Specific implementation method four: Combination Figure 1 and Figure 2 In this embodiment, the motor hub drive shaft 1-5 is a stepped gear shaft. With this configuration, the motor hub drive shaft 1-5 is coaxially inserted inside the drive wheel motor rotor housing 2-11. A disc cover structure is connected to the end of the motor hub drive shaft 1-5, and six screw holes are provided on it for mounting the disc cover to the outside of the center hole of the hub center wheel 1-1, achieving the effect of sealing the internal structure of the hub. Other components and connections are the same as in specific embodiments one, two, or three.

[0043] Specific Implementation Method Five: Combining Figure 1 and Figure 2In this embodiment, the deformable hub drive wheel 1 further includes multiple hydraulic cylinder guide sleeves 1-10. Each hub hydraulic cylinder piston 1-2 has a hydraulic cylinder guide sleeve 1-10 fitted onto its telescopic end. This arrangement ensures that each hub hydraulic cylinder has a hydraulic cylinder guide sleeve 1-10 between it and its piston 1-2, supporting the piston rod and ensuring linear movement of the piston rod within the hydraulic cylinder, thus reducing friction between the piston rod and the inner wall of the hydraulic cylinder. Other components and connections are the same as in specific embodiments one, two, three, or four.

[0044] Specific Implementation Method Six: Combination Figure 3 This embodiment describes a lower leg 2 comprising a 3D metal-printed lower leg skeleton 2-2, an ankle joint protective shell 2-3, and a motor drive assembly. The ankle joint protective shell 2-3 is installed in the lower part of the 3D metal-printed lower leg skeleton 2-2, and the motor drive assembly is embedded in the ankle joint protective shell 2-3 and transmits driving power and torque to the motor hub drive shaft 1-5.

[0045] In this configuration, the lower leg support frame is designed using finite element software and then printed from metal. By selecting high-strength alloy materials and combining them with the layer-by-layer stacking process of 3D printing, a very robust and durable wheel-leg frame can be manufactured, capable of withstanding the complex loads, impacts, and high-pressure environments required for robot movement. This high-strength frame structure is difficult to achieve with traditional manufacturing processes, especially for complex geometries and extreme working conditions. This metal-printed lower leg frame achieves mechanical integration, integrating functional components such as hydraulic sensors, cable channels, hydraulic servo valves, and hydraulic system channels into a single frame structure. This avoids the need for additional components in traditional designs, further improving the compactness and usable space of the robot's mechanical components. Other components and connections are the same as in specific implementation methods one, two, three, four, or five.

[0046] Specific implementation method seven: Combination Figure 3This embodiment describes a motor drive assembly comprising a motor end cover 2-5, a drive wheel motor gear train 2-6, a drive wheel motor rotor disk 2-9, a drive wheel motor stator coil 2-10, a drive wheel motor rotor housing 2-11, an inner bearing 2-12 at the motor output end, a wheel axle end cover 2-13, an outer bearing 2-14 at the motor output end, and a planetary gear output flange 2-15. The drive wheel motor stator coil 2-10 is installed inside the drive wheel motor rotor housing 2-11, the drive wheel motor rotor disk 2-9 is installed on one side of the drive wheel motor rotor housing 2-11, the drive wheel motor gear train 2-6 is installed inside the drive wheel motor stator coil 2-10, the planetary gear output flange 2-15 is installed on the drive wheel motor gear train 2-6, the inner bearing 2-12 and the outer bearing 2-14 at the motor output end are installed on the outer side of the planetary gear output flange 2-15, and the wheel axle end cover 2-13 and the motor end cover 2-5 are respectively installed on the two side end faces of the ankle joint protective shell 2-3.

[0047] This configuration facilitates the rotation of the drive motor hub transmission shaft 1-5. Other components and connections are the same as in specific embodiments one, two, three, four, five, or six.

[0048] Specific implementation method eight: Combination Figure 3 In this embodiment, the lower leg 2 further includes a knee joint inner bushing 2-1, a pressure sensor 2-7, and a knee joint hydraulic servo valve 2-8; the knee joint inner bushing 2-1 is horizontally embedded in the upper part of the 3D metal printed lower leg skeleton 2-2, and the pressure sensor 2-7 and the knee joint hydraulic servo valve 2-8 are installed in the middle of the 3D metal printed lower leg skeleton 2-2.

[0049] This configuration integrates the mechanical structure of the lower leg skeleton, allowing functional components such as hydraulic sensors 2-7, cable channels, knee joint hydraulic servo valves 2-8, and hydraulic system channels to be integrated into a single skeleton structure. This avoids the need for additional components in traditional designs, further improving the compactness and usable space of the robot's mechanical components. Other components and connections are the same as in any of the specific implementation methods one through seven.

[0050] Specific Implementation Method Nine: Combining Figure 3 In this embodiment, the lower leg 2 further includes an encoder 2-16 and an encoder end cap 2-4. The encoder 2-16 is mounted inside the ankle joint protective shell 2-3 via the encoder end cap 2-4. Other components and connections are the same as in any of the specific embodiments one to eight.

[0051] Specific Implementation Method Ten: Combining Figure 4This embodiment describes a drive wheel motor gear system 2-6 comprising an internal gear ring 261, multiple planetary gears 262, a motor drive shaft 263, a planetary gear output shaft 264, a deep groove ball bearing 265, an 8mm motor drive shaft shoulder retaining ring 266, a 7mm motor drive shaft shoulder retaining ring 267, a motor hub drive shaft elastic retaining ring 268, and a planetary gear output shaft elastic retaining ring 269. The internal gear ring 261 is installed inside the drive wheel motor rotor housing 2-11, and the motor drive shaft 263 is installed inside the internal gear ring 261, along with a sun gear 264. Inside 611, multiple planetary gears 262, sun gear 2611, and internal gear ring 261 mesh with each other. The planetary gear output shaft 264 passes through the planetary gears 262. The deep groove ball bearing 265 is fitted on the planetary gear output shaft 264. The planetary gear output shaft elastic retaining ring 269 is installed at the end of the planetary gear output shaft 264. The motor hub drive shaft elastic retaining ring 268 and the 8mm motor drive shaft shoulder retaining ring 266 are installed at one end of the motor drive shaft 263. The 7mm motor drive shaft shoulder retaining ring 267 is installed at the other end of the motor drive shaft 263.

[0052] In this configuration, the motor hub drive shafts 1-5 are stepped gear shafts, coaxially inserted inside the motor rotor housing. The drive wheel motor rotor housing is attached to the drive wheel motor stator coil. Multiple planetary gears are rotatably mounted in a circular array inside the motor rotor housing and stator coil, all meshing with the gears on the motor hub drive shaft. Three planetary gear output shafts are connected to planetary gear output flanges, outputting torque and speed for the next stage of transmission. An ankle joint protective shell is fitted onto the outside of the motor rotor housing, and a motor end cover is provided on the outside of the motor rotor housing. The motor end cover is connected to the ankle joint protective shell by multiple connecting screws. An encoder is installed at the end of the motor hub drive shaft, and an encoder end cover is provided on the outside of the encoder. The encoder end cover is connected to the motor end cover by multiple connecting screws. Other components and connections are the same as in any of the specific embodiments one to eight.

[0053] Combination Figures 1 to 7 Explanation of the working principle of this invention:

[0054] Reference Figure 1 and Figure 2 The motor hub drive shaft 1-5 is a stepped gear shaft, which is coaxially inserted into the drive wheel motor rotor housing 2-11. A disc cover structure is connected to the end of the motor hub drive shaft 1-5, with six screw holes for mounting the disc cover to the outside of the center hole of the hub center wheel 1-1, thus sealing the internal structure of the hub.

[0055] Reference Figure 2The center hole wall of the hub center wheel 1-1 and the oil runner joint 1-12 have screw holes. The oil runner joint is connected to the center hole by mounting screws. The length of the oil runner joint is less than the length of the hub center hole. A pair of bare joint hub bearings 1-3, which are deep groove ball bearings, are symmetrically arranged on both sides with space left. The bare joint hub bearings 1-3 can effectively withstand the radial load and a certain axial load during hub transmission, ensuring the stability and efficiency of the motor hub during operation. The bearing support ensures the smooth operation of the motor transmission system at high speeds and effectively reduces friction and wear, extending the service life of the drive wheel. The center hole wall has slots on both sides to fix the outer rings of the two deep groove ball bearings. The inner ring of the left bearing is fixed by the bare joint hub bearing retainer ring 1-4, and the inner ring of the right bearing is fixed by the axle end cap 2-13. The motor hub drive shaft 1-5 is coaxially inserted into the center hole wall and the inside of the bearings.

[0056] Reference Figure 2 The hub center wheel 1-1 features a derivative design with a complex surface structure, which helps reduce hub weight and increase strength. The hub center wheel 1 has a symmetrical structure with six hydraulic cylinders arranged in a ring array. An arc-shaped support structure exists between adjacent hydraulic cylinders, increasing the overall structural reliability. Each hub arc 1-7 has reinforcing ribs on its inner side, effectively increasing the support capacity of the hub arc segment. A hydraulic cylinder guide sleeve 1-10 is located between each hub hydraulic cylinder and its piston 1-2 to support the piston rod, ensuring linear movement of the piston rod within the hydraulic cylinder and reducing friction between the piston rod and the inner wall of the hydraulic cylinder. Two adjacent hub arcs 1-7 form a pair, with three hub arc pairs existing around the entire circumference of the hub. Each hub arc pair is connected by a hub arc connecting rod shaft 1-9 and a pair of hub arc connecting rods 1-8. The two hub arcs 1-7 within the same hub arc pair are connected by the hub arc connecting rod shaft 1-9. Each piston rod head is fixed with a front lug 1-11. The hub arc connecting rod shaft 1-9 connects the front lug 1-11 to the hub arc connecting rod 1-8 or directly to the front lug 1-11 and the hub arc 1-7. This ensures that each hub hydraulic cylinder piston 1-2 can push the connecting rod in each pair of adjacent arc-shaped hubs or directly push two adjacent hub arc segments, causing each hub arc 1-7 to move in its corresponding direction, thereby changing the hub geometry. In a hub triangular shape, each hub arc is one side of the triangle it forms, and the side of this triangle is not strictly a straight line. Three flat tires 1-6 are specially designed to wrap around the hub arc 1-7 and are reinforced with screws through the screw holes on the hub arc 1-7. The tire surface has good elasticity and grip. The shape of the flat tires adjusts according to the hub shape, ensuring that the deformable hub drive wheel 1 has stable ground contact and movement performance.

[0057] Reference Figures 2 to 4The rotor housing 2-11 of the drive wheel motor is attached to the stator coil of the drive wheel motor. Multiple planetary gears 262 are rotatably mounted in a ring array inside the rotor housing and stator coil, and all of these planetary gears 262 mesh with the gear portion on the motor drive shaft 263. Three planetary gear output shafts 264 are connected to planetary gear output flanges 2-15, outputting torque and speed to drive the next stage motor hub drive shaft 1-5. An ankle joint protective shell 2-3 is fitted onto the outside of the motor rotor housing, and the drive wheel motor rotor disc 2-9 is fitted onto the side of the rotor housing. The motor rotor disc is the core component of the electric drive system, responsible for converting electrical energy into mechanical energy and providing driving force. Through electromagnetic interaction with the stator, the rotor disc drives the motor to rotate, thereby driving the drive wheel to rotate and completing the power transmission. A motor end cover 2-5 is provided on the outside of the motor rotor housing, and the motor end cover is connected to the ankle joint protective shell 2-3 by multiple connecting screws. An encoder 2-16 is mounted at the end of the motor hub drive shaft 1-5. An encoder end cover 2-4 is located on the outside of the encoder, and the encoder end cover is connected to the motor end cover 2-5 by multiple connecting screws. With this configuration, the ankle joint is driven by a frameless torque motor connected in series with a planetary reducer, transmitting power through planetary gears 262. The motor driving the wheel is located inside the lower leg and is driven by an external rotor motor connected in series with a planetary reducer. This design improves the power-to-weight ratio and makes the structure more compact. The planetary reducer is built into the center of the motor stator, ensuring coaxiality while maximizing installation space savings. The axle end cover 2-13 is designed in a stepped manner, with a small-hole shaft at the end near the drive wheel and a large-hole shaft at the end near the lower leg. A groove is provided on the inner wall of the center hole of the large-hole shaft to fix the inner bearing 2-14 of the motor output end. The axle end cover 2-13 is connected to the ankle joint protective shell 2-3 by multiple connecting screws.

[0058] Reference Figure 3 The 3D-printed metal leg skeleton 2-2 is designed using finite element software and then printed from metal. By selecting high-strength alloy materials and combining them with the layer-by-layer stacking process of 3D printing, a very robust and durable wheel-leg skeleton can be manufactured, capable of withstanding the complex loads, impacts, and high-pressure environments required for robot movement. This high-strength skeleton structure is difficult to achieve with traditional manufacturing processes, especially for complex geometries and extreme working conditions. This metal-printed leg skeleton achieves mechanical integration, integrating functional components such as the hydraulic pressure sensor 2-7, cable channels, knee joint hydraulic servo valve 2-8, and hydraulic system channels into a single skeleton structure. This avoids the need for additional components in traditional designs, further improving the compactness and usable space of the robot's mechanical components.

[0059] refer to Figure 2 and Figure 4Multiple planetary gears 262 are rotatably mounted in a ring array inside the drive wheel motor gear train 2-6, located inside the drive wheel stator coil 2-10. Each planetary gear 262 externally meshes with the gear portion on the motor 263 drive shaft 1-5 and internally meshes with the outer internal gear ring 261. Three planetary gear output shafts 264 are connected to the planetary gear output flanges 2-15, outputting speed and torque for the next stage of transmission. An 8mm motor drive shaft shoulder retaining ring 266 restricts the axial movement of the inner bearing 2-12 at the motor output end. A 7mm motor drive shaft shoulder retaining ring 267 distributes pressure and provides elasticity, ensuring a tight and stable connection. The planetary gear output shaft 264 is a stepped shaft, with two adjacent deep groove ball bearings 265 arranged on the same stepped shaft for support. The deep groove ball bearings 265 on the stepped shaft are limited by the steps of the stepped shaft and the steps of the inner center holes of the planetary gears 262. The elastic retaining ring 268 on the motor hub drive shaft and the stepped design on the motor hub drive shaft 1-5 restrict the sun gear 2611 to a fixed position. Similarly, the elastic retaining ring 269 on the planetary gear output shaft and the stepped design on the planetary gear output shaft 264 restrict the planetary gears 2611 to a fixed position. These elastic retaining rings secure the gears to the shafts, preventing axial movement or detachment. These elastic retaining rings provide locking and restraint during gear installation, ensuring the gears operate in the correct position. The motor drive shaft 263 is designed as a stepped shaft, with a threaded hole at its large-diameter end for connection between the motor drive shaft 263 and the drive wheel motor rotor disc 2-9.

[0060] refer to Figures 5 to 7 The robot can perceive and analyze various ground conditions in real time, automatically adjusting the shape and structure of its wheel hubs according to different ground conditions. Six hydraulic cylinders drive a linkage system to control the transformation of the arc-shaped wheel hubs into circles or triangles. Each hydraulic cylinder piston pushes a linkage in each pair of adjacent arc-shaped wheel hubs, moving them in the corresponding direction and thus changing the wheel hub's geometry. On hard surfaces or smooth surfaces, the wheel hubs revert to a compact, standard circle. This design helps improve motion efficiency and speed while reducing energy consumption, making the robot more stable and faster when traveling on flat ground. The standard circular structure minimizes friction with the ground, optimizing power output and energy utilization, thereby extending the robot's runtime and performance. When facing irregular obstacles or uneven ground, the wheel hubs automatically transform into angular geometries, such as triangles or other polygons, to enhance obstacle-crossing capabilities. Through this deformation, the robot achieves better grip and support, effectively overcoming various obstacles and ensuring stable travel on complex terrain. This adaptive morphological adjustment not only improves the robot's obstacle-crossing ability but also provides better stability, reducing the risk of tipping over or losing balance.

[0061] Robots equipped with this novel wheel-leg mechanism can move freely, climb, and overcome obstacles in complex and varied environments, expanding their application scenarios. Whether exploring unknown terrain, performing search and rescue missions, or conducting logistics and transportation under different environmental conditions, this advanced wheel-leg system provides superior performance and flexibility, enabling robots to cope with various terrain challenges and meet diverse mission requirements.

[0062] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make other changes within the spirit of the invention and apply it to fields not mentioned in the invention. Of course, all such changes made in accordance with the spirit of the invention should be included within the scope of protection claimed by the invention.

Claims

1. A deformable robot wheel-leg mechanism, characterized in that: It includes a deformable hub drive wheel (1) and a lower leg (2). The deformable hub drive wheel (1) is the ankle joint drive component of the wheel-footed robot. The deformable hub drive wheel (1) is rotatably installed on the lower part of the lower leg (2). The ankle joint drive component drives the linkage system through six hydraulic cylinders to control the arc hub to deform into a circle or a triangle. Each hub hydraulic cylinder piston (1-2) pushes the hub arc linkage (1-8) in each pair of adjacent hub arc assemblies to move it in the corresponding direction, thereby changing the geometry of the hub. The deformable hub drive wheel (1) includes a hub center wheel (1-1), six hub hydraulic cylinder pistons (1-2), a motor hub drive shaft (1-5), a hub arc (1-7), a hub arc connecting rod (1-8), a hub arc connecting rod shaft (1-9), a flat tire (1-6), a drive wheel oil flow joint (1-12), and two ankle joint hub bearings (1-3). The motor hub drive shaft (1-5) is rotatably inserted into the hub center wheel (1-1), and the six hub hydraulic cylinder pistons (1-2) are radially mounted on the hub center wheel (1-1) with the hub center wheel (1-1) as the center. The telescopic end of the piston (1-2) of each wheel hub hydraulic cylinder is connected to the connection point of two adjacent wheel hub arcs (1-7). Two adjacent wheel hub arcs (1-7) form a group of wheel hub arc assemblies. Two adjacent groups of wheel hub arc assemblies are rotatably connected by a pair of wheel hub arc connecting rods (1-8) and wheel hub arc connecting rod shafts (1-9). Two wheel hub arcs (1-7) in the same wheel hub arc assembly are connected by wheel hub arc connecting rod shafts (1-9). A flat tire (1-6) is installed on the wheel hub arc assembly, and the flat tire (1-6) is adjusted according to the shape of the wheel hub. Multiple groups of wheel hub arc assemblies form an arc-shaped wheel hub. The drive wheel oil-running joint (1-12) is installed between the hub center wheel (1-1) and the motor hub drive shaft (1-5), and the two ankle joint hub bearings (1-3) are located on the left and right sides of the drive wheel oil-running joint (1-12) respectively; The lower leg (2) includes a 3D metal-printed lower leg skeleton (2-2), an ankle joint protective shell (2-3), and a motor drive assembly. The ankle joint protective shell (2-3) is installed in the lower part of the 3D metal-printed lower leg skeleton (2-2), and the motor drive assembly is embedded in the ankle joint protective shell (2-3) and transmits the driving power and torque to the motor hub drive shaft (1-5).

2. The deformable robot wheel-leg mechanism according to claim 1, characterized in that: The motor hub drive shaft (1-5) is a stepped gear shaft.

3. The deformable robot wheel-leg mechanism according to claim 2, characterized in that: The deformable hub drive wheel (1) also includes multiple hydraulic cylinder guide sleeves (1-10), with a hydraulic cylinder guide sleeve (1-10) fitted on the telescopic end of each hub hydraulic cylinder piston (1-2).

4. The deformable robot wheel-leg mechanism according to claim 3, characterized in that: The motor drive assembly includes a motor end cover (2-5), a drive wheel motor gear train (2-6), a drive wheel motor rotor disc (2-9), a drive wheel motor stator coil (2-10), a drive wheel motor rotor housing (2-11), an inner bearing at the motor output end (2-12), a wheel axle end cover (2-13), an outer bearing at the motor output end (2-14), and a planetary gear output flange (2-15). The stator coil (2-10) of the drive wheel motor is installed inside the rotor housing (2-11) of the drive wheel motor, and the rotor disc (2-9) of the drive wheel motor is installed on one side of the rotor housing (2-11) of the drive wheel motor. The drive wheel motor gear train (2-6) is installed inside the drive wheel motor stator coil (2-10), the planetary gear output flange (2-15) is installed on the drive wheel motor gear train (2-6), the inner bearing (2-12) and the outer bearing (2-14) of the motor output end are installed on the outer side of the planetary gear output flange (2-15), and the wheel axle end cover (2-13) and the motor end cover (2-5) are respectively installed on the two side end faces of the ankle joint protective shell (2-3).

5. The deformable robot wheel-leg mechanism according to claim 4, characterized in that: The lower leg (2) also includes a knee joint inner bushing (2-1), a pressure sensor (2-7), and a knee joint hydraulic servo valve (2-8). The medial knee joint bushing (2-1) is horizontally embedded in the upper part of the 3D metal-printed lower leg frame (2-2), and the pressure sensor (2-7) and the knee joint hydraulic servo valve (2-8) are installed in the middle of the 3D metal-printed lower leg frame (2-2).

6. The deformable robot wheel-leg mechanism according to claim 5, characterized in that: The lower leg (2) also includes an encoder (2-16) and an encoder end cap (2-4), with the encoder (2-16) mounted inside the ankle protection shell (2-3) via the encoder end cap (2-4).

7. The deformable robot wheel-leg mechanism according to claim 6, characterized in that: The drive wheel motor gear system (2-6) includes an internal gear ring (261), multiple planetary gears (262), a motor drive shaft (263), a planetary gear output shaft (264), a deep groove ball bearing (265), an 8mm motor drive shaft shoulder retaining ring (266), a 7mm motor drive shaft shoulder retaining ring (267), a motor hub drive shaft elastic retaining ring (268), and a planetary gear output shaft elastic retaining ring (269). An internal gear ring (261) is installed inside the rotor housing (2-11) of the drive wheel motor. The motor drive shaft (263) is installed inside the sun gear (2611) inside the internal gear ring (261). Multiple planetary gears (262), the sun gear (2611) and the internal gear ring (261) mesh with each other. The planetary gear output shaft (264) passes through the planetary gears (262). A deep groove ball bearing (265) is fitted on the planetary gear output shaft (264). The planetary gear output shaft elastic retaining ring (269) is installed at the end of the planetary gear output shaft (264). The motor hub drive shaft elastic retaining ring (268) and the 8mm motor drive shaft shoulder retaining ring (266) are installed at one end of the motor drive shaft (263). The 7mm motor drive shaft shoulder retaining ring (267) is installed at the other end of the motor drive shaft (263).

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