Modularized wheel-foot switching leg structure for anti-explosion environment and quadruped robot

Abstract

The invention discloses a modular wheel-foot switching leg structure for an anti-explosion environment and a quadruped robot, and relates to the technical field of robots. The problems that an existing quadruped robot leg structure is complex and cumbersome in anti-explosion design, limited in load capacity and single in motion mode due to the fact that the existing quadruped robot leg structure depends on motor driving are solved. The anti-explosion leg comprises a shank section, a thigh section with an anti-explosion function and a knee joint, wherein the thigh section and the shank section are hinged through the knee joint; the shank section is of a modular structure capable of being rapidly detached and replaced, and the lower portion of the shank section is connected with a foot type module or a wheel type module. Full-hydraulic drive is adopted to replace a motor, the electric spark risk is fundamentally eliminated, and the anti-explosion and protection requirements are met; the unstructured terrain trafficability and the flat road surface high-speed maneuverability are both considered through wheel-foot mode switching. The device is suitable for inspection and transportation operation of high-risk environments such as petroleum and chemical engineering.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of robot technology, in particular to a modular wheel-foot switching leg structure for an explosion-proof environment and a quadruped robot. In particular, a modular hydraulic drive leg structure capable of quickly switching between wheeled motion and foot motion for use in high-risk explosion-proof environments and a quadruped robot having the structure. BACKGROUND

[0002] Currently, the inspection and transportation operations in high-risk explosion-proof environments still mainly rely on traditional manual methods and existing robot technologies, but they all have significant limitations. For example, manual operation for inspection and transportation operations is flexible, but it faces high safety risks, and also has the problems of low efficiency and high cost. The existing wheeled / track-type robots have poor terrain adaptability, and the explosion-proof treatment of the motor drive system makes the whole machine heavy and reduces the mobility. Foot-type robots have strong terrain adaptability, but they have the problems of slow motion speed, weak load capacity, and difficulty in explosion-proof design of multi-joint electrical systems.

[0003] Chinese patent application CN118907264A discloses a quadruped robot leg structure and a quadruped robot. By setting the thigh rotation assembly, the calf rotation assembly, and the telescopic foot assembly, and using the parallelogram structure to unify the rotation reference of the thigh and the calf on the thigh rotation motor, the joint control precision of the leg motion is effectively improved. At the same time, through the cooperation of the sliding buckle assembly and the dismounting assembly, the telescopic adjustment and safety locking of the foot support are realized, and the adaptability of the leg to the terrain is improved.

[0004] However, the existing technology still has the following deficiencies: First, the power source is a motor-driven element such as a rotary cylinder and a telescopic cylinder, which has the risk of electric spark ignition in a high-risk explosion-proof environment. Although explosion-proof treatment can be performed, it significantly increases the system complexity and the weight of the whole machine, making it difficult to meet the requirements of lightweight, high safety, and high reliability in the highest explosion-proof level (such as IIC-T6) scenarios. Second, the load capacity of the structure is limited by the power density of the motor, making it difficult to handle heavy materials (such as more than 70 kg). In addition, the leg structure only has a foot walking mode and lacks the ability of wheeled high-speed motion, which cannot meet the needs of unstructured terrain passability and efficient mobility on flat roads, limiting its application in long-distance rapid response scenarios.

[0005] In summary, the existing quadruped robot leg structure relies on motor drive, resulting in the problems of complex and heavy explosion-proof design, limited load capacity, and single motion mode. SUMMARY

[0006] The application aims to solve the problems of complex and heavy anti-explosion design, limited load capacity and single movement mode of the existing four-legged robot leg structure which relies on motor driving.

[0007] The technical scheme of the application is:

[0008] The application discloses a modular wheel-foot switching leg structure for an anti-explosion environment, which comprises a thigh section, a calf section and a knee joint with an anti-explosion function, and the thigh section and the calf section are hinged through the knee joint.

[0009] Further, the thigh section comprises a thigh skeleton, a hip joint, a side swing and pitch adapter and a pitch driving unit, the thigh skeleton is integrally formed by 3D printing, and the thigh skeleton is provided with a rib for conveying hydraulic oil, the hip joint is installed at the upper part of the thigh skeleton, the hip joint is connected with the robot main body through the side swing and pitch adapter, the robot main body drives the side swing and pitch adapter through a side swing cylinder, and the hip joint is driven to realize pitch through a linear cylinder.

[0010] Further, the hip joint comprises a hip magnet mounting base, a hip joint encoder, a hip joint encoder sealing cover and a hip pitch oil running joint, the hip pitch oil running joint is rotatably installed in the width direction of the thigh skeleton, the hip magnet mounting base is installed on the thigh skeleton outside the hip pitch oil running joint, the hip joint encoder is installed at the end of the hip magnet mounting base and is fixed by the hip joint encoder sealing cover.

[0011] Further, the pitch driving unit comprises a pitch hydraulic cylinder, a pitch two-force rod shaft, a pitch sliding block, a hip two-force rod, a hip two-force rod shaft, a sliding rail and a pitch block, the pitch hydraulic cylinder is installed in the length direction of the thigh skeleton, the extending end of the pitch hydraulic cylinder faces the hip joint, the sliding rail is installed in front of the extending end of the pitch hydraulic cylinder, one end of the hip two-force rod is connected with the extending end of the pitch hydraulic cylinder through the pitch two-force rod shaft, the other end of the hip two-force rod is connected with the pitch block installed on the hip pitch oil running joint through the hip two-force rod shaft, wherein the lower end of the pitch sliding block is slidably installed on the sliding rail, and the upper end of the pitch sliding block is connected with the extending end of the pitch hydraulic cylinder.

[0012] Further, the knee joint comprises a knee joint shaft, a knee joint magnet mounting seat, a magnet, a magnetic encoder and a knee joint bearing mounting seat, the knee joint shaft is rotatably installed at the lower part of the thigh skeleton, the magnet is embedded at the end of the knee joint shaft through the knee joint magnet mounting seat, the knee joint sealing cover is installed on the magnet, the magnetic encoder is installed on the knee joint sealing cover outside the magnet and is encapsulated through the knee joint bearing mounting seat.

[0013] Preferably, the knee joint bearing mounting seat is encapsulated in a glue-sealed explosion-proof mode.

[0014] Further, the knee joint further comprises a crank slider pitching mechanism, the crank slider pitching mechanism comprises a knee joint hydraulic cylinder, a knee joint sliding rail, a knee joint slider and a knee joint two-force lever, the knee joint hydraulic cylinder is installed in the length direction of the thigh skeleton, and the extension end of the knee joint hydraulic cylinder faces the knee joint side, the knee joint sliding rail is installed on the thigh skeleton, the extension end of the knee joint hydraulic cylinder is connected with one end of the knee joint two-force lever through the knee joint slider, the knee joint slider is slidably installed on the knee joint sliding rail, and the other end of the knee joint two-force lever is rotatably connected with the upper part of the lower leg segment.

[0015] Further, the lower leg segment comprises a lower leg aluminum piece and a lower leg end connecting piece, the upper part of the lower leg aluminum piece is connected with the knee joint, and the other end of the knee joint two-force lever is connected with the lower leg aluminum piece, so that the lower leg aluminum piece is driven to pitch, and the lower leg end connecting piece is detachably installed at the lower part of the lower leg aluminum piece.

[0016] Preferably, the lower leg end connecting piece is a foot module or a wheel module.

[0017] The application further provides a quadruped robot, which comprises a robot main body and the modular wheel-foot switching leg structure for an explosion-proof environment.

[0018] Compared with the prior art, the application has the following effects:

[0019] 1. The application solves the contradiction between explosion-proof safety and structural compactness. This invention fundamentally resolves the conflict between explosion-proof and lightweight design by combining a fully hydraulic drive with a sealed explosion-proof sensor (magnetic encoder). Specifically, the pitch cylinders at the hip and knee joints, and the knee joint hydraulic cylinder, serve as the power source, replacing the motor which is prone to generating electrical sparks and eliminating the ignition source. Simultaneously, the magnetic encoder is encapsulated in adhesive via the knee joint bearing mounting, ensuring that the sensor portion also meets explosion-proof requirements. This design eliminates the need for an additional heavy and bulky explosion-proof shell on the entire leg structure, thus achieving lightweight and compact design while meeting the highest IIC-T6 explosion-proof rating and IP66 protection rating. This compactness is directly reflected in the "one-piece 3D-printed thigh skeleton," enabling the robot to operate flexibly in confined explosion-proof environments.

[0020] 2. This invention can achieve the effect of strong load and high power density output:

[0021] This invention achieves powerful load-bearing capacity through the synergistic design of a "high-power-density hydraulic cylinder" and a "3D-printed integrated thigh skeleton and its internal ribs." The pitch and knee joint hydraulic cylinders directly provide enormous linear thrust, which is converted into strong joint torque (≥450 N·m) through efficient transmission mechanisms such as the hip lever and crank-slider pitch mechanism—a capability that motors struggle to achieve. Simultaneously, the internal ribs of the thigh skeleton directly serve as hydraulic circuits, replacing complex external steel pipes and hoses. This not only simplifies the structure and reduces leakage points, improving reliability, but more importantly, it achieves a high degree of integration of the hydraulic circuits, providing an efficient and reliable delivery channel for the hydraulic system. Together, these features support the robot's outstanding performance with a 70 kg rated load and a 1:1 load-to-weight ratio.

[0022] 3. This invention can achieve adaptive switching between wheel and foot modes to balance passability and maneuverability: This invention addresses the limitations of a single movement mode through a modular design featuring a "quick-changeable lower leg end connector." The lower part of the aluminum lower leg component is designed with a standard interface for quick installation of either a foot-type or wheel-type module. When adapting to rugged terrain, the foot-type module is installed, utilizing a three-degree-of-freedom (hip pitch, hip sway, knee pitch) leg structure driven by hydraulic cylinders to overcome obstacles and climb slopes. When entering flat terrain, the wheel-type module (driven by a hydraulic motor) is installed, instantly transforming the system into a four-wheel drive mode for high-speed mobility. This physical switching based on a quick-change mechanical and hydraulic interface is key to achieving the contrasting performance of a maximum wheel speed of 30 km / h and an obstacle-crossing capability of 200 mm, truly enabling adaptive selection of the optimal movement mode based on terrain.

[0023] 4. This invention can improve the system's control accuracy and reliability: This invention ensures control precision under hydraulic drive through a feedback system composed of a hip joint encoder, a magnetic encoder, and a non-contact magnet. The encoder directly measures the rotation angles of the hip pitch joint and knee joint axes, providing high-precision joint position feedback to the control system and achieving accurate servo control. Furthermore, two independently distributed hydraulic power units provide power redundancy. If one unit fails, the other can still maintain the robot's basic motion capabilities, greatly improving the overall system reliability. The 3D-printed integrated skeleton reduces connectors and assembly steps, structurally lowering the failure rate. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0025] Figure 2 yes Figure 1 The main view.

[0026] Figure 3 yes Figure 1 Side view.

[0027] Figure 4 yes Figure 1 View from point A.

[0028] Figure 5 yes Figure 4 A magnified view of a section at point C.

[0029] Figure 6 yes Figure 1 Top view.

[0030] Figure 7 yes Figure 6 A magnified view of a section at point B.

[0031] Figure 8 This is a schematic diagram of the overall structure of the quadruped robot of the present invention, wherein the lower part of the lower leg segment is connected to the foot module.

[0032] Figure 9 This is a schematic diagram of the overall structure of the quadruped robot of the present invention, wherein the lower part of the lower leg segment is connected to a wheel module.

[0033] In the picture:

[0034] 1. Side swing and pitch adapter; 2. Hip two-force bar; 3. Hip two-force bar shaft; 4. Pitch two-force bar shaft; 5. Thigh frame; 6. Hip magnet mounting base; 7. Hip joint encoder sealing cover; 9. Bearing; 10. Hip pitch oil-supported joint; 17. Knee joint bearing mounting base; 18. Magnetic encoder; 19. Magnet; 20. Knee joint magnet mounting base; 21. Knee joint shaft; 40. Hip joint encoder; 50. Pitch hydraulic cylinder; 51. Pitch slider; 52. Slide rail; 53. Knee joint hydraulic cylinder; 54. Knee joint slide rail; 55. Knee joint slider; 56. Knee joint two-force bar; 57. Lower leg aluminum part; 58. Foot body; 59. Pad. Detailed Implementation

[0035] Specific implementation method one: Combining Figures 1 to 9 This embodiment describes a thigh segment, a lower leg segment, and a knee joint with explosion-proof function. The thigh segment and the lower leg segment are hinged together by the knee joint. The upper part of the thigh segment is a hydraulically driven hip joint with pitch and lateral freedom. The lower leg segment is a modular structure that can be quickly replaced. The lower part of the lower leg segment is connected to a foot module or a wheel module.

[0036] This implementation method replaces the traditional electric motor drive with a "hydraulic drive", fundamentally eliminating the source of electric sparks and meeting the safety requirements of high-risk explosion-proof environments such as petroleum and chemical industries (IIC-T6 level).

[0037] In this embodiment, a single leg can switch between two modes: legged and wheeled. In legged mode (connected to the legged module), the robot utilizes the pitch and lateral freedom of the hip joint and the knee joint to achieve biomimetic walking, giving it strong adaptability to unstructured terrain (such as climbing slopes and overcoming obstacles). In wheeled mode (connected to the wheeled module), the robot switches to wheeled rolling, achieving speeds significantly higher than legged walking on flat surfaces, greatly improving work efficiency and endurance, and addressing the pain point of traditional quadruped robots being "slow."

[0038] This implementation uses a hydraulic drive system, which provides power density and torque output far exceeding that of a motor. This allows the robot to carry a rated load of 70kg or even 120kg with a self-weight of 70kg, achieving a load-to-weight ratio of 1:1, making it capable of heavy-duty transportation tasks.

[0039] The explosion-proof function claimed in this embodiment is manifested not only through hydraulic drive, but also through the explosion-proof treatment of electrical components, especially the use of glue sealing for all encoders.

[0040] Specific Implementation Method Two: Combining Figures 1 to 4This embodiment describes a thigh segment comprising a thigh frame 5, a hip joint, a lateral tilt-pitch adapter 1, and a pitch drive unit. The thigh frame 5 is integrally formed by 3D printing and has ribs for conveying hydraulic oil. The hip joint is mounted on the upper part of the thigh frame 5 and is connected to the robot body via the lateral tilt-pitch adapter 1. The robot body drives the lateral tilt-pitch adapter 1 via a lateral tilt cylinder, and the hip joint is driven by a linear cylinder to achieve pitch. The pitch drive unit is installed inside the thigh frame 5 and hydraulically drives the hip joint to rotate and achieve pitch.

[0041] The "3D-printed one-piece thigh skeleton" reduces the possibility of mechanical sparks (friction, impact sparks) caused by loosening of parts or structural breakage due to vibration and impact. It eliminates a large number of external steel pipes, joints and fasteners, greatly reducing the weight of the legs (which is crucial for increasing the robot's load and endurance) and making the structure exceptionally compact, avoiding the entanglement, pulling and collision that external oil pipes may cause during complex movements.

[0042] In this implementation, the independent "lateral tilt-pitch adapter" and the "pitch drive unit" integrated into the frame together constitute the two degrees of freedom drive source for the hip joint. This layout makes the power transmission paths of lateral tilt and pitch movements independent (decoupled), which not only simplifies the complexity of the control algorithm, but also fully leverages the advantages of the high power density of hydraulic drive, providing a solid mechanical structure guarantee for the robot to achieve strong load capacity, flexible lateral movement, and stable adaptation to complex terrain.

[0043] Specific implementation method three: Combining Figures 1 to 7 This embodiment describes a hip joint including a hip magnet mounting base 6, a hip joint encoder 40, a hip joint encoder sealing cover 7, and a hip pitching and sliding joint 10. The hip pitching and sliding joint 10 is rotatably mounted in the width direction of the thigh skeleton 5. The hip magnet mounting base 6 is mounted on the thigh skeleton 5 on the outside of the hip pitching and sliding joint 10. The hip joint encoder 40 is mounted on the end of the hip magnet mounting base 6 and is sealed and fixed by the hip joint encoder sealing cover 7.

[0044] This implementation achieves integrated high-precision joint angle feedback and hydraulic power transmission while ensuring the highest level of explosion-proof safety and environmental reliability. Specifically, the hip pitch hydraulic joint (located on the robot body) connects the hydraulic circuits of two parts. The hydraulic circuit along the axis is achieved through the side-swing pitch adapter 1, then the hydraulic circuit goes to the hip pitch hydraulic joint, and then through the hip pitch hydraulic joint to the thigh skeleton, directly supplying oil to the joint drive unit. This achieves the shortest and most integrated power transmission path, avoiding the risks of external oil pipes getting tangled and worn during joint rotation.

[0045] The "hip joint encoder" installed at the end of the oil-carrying shaft and the "hip magnet mount 6" fixed on the thigh skeleton together constitute a non-contact magnetic coding measurement system, which can detect the rotation angle of the oil-carrying shaft (i.e., the hip joint) in real time and with high precision, providing crucial position feedback information for the robot's motion control.

[0046] To ensure the absolute safety of this precision sensing system in high-risk environments, the "hip joint encoder sealing cover 7" plays a crucial role. Together with related components, it forms a sealed cavity, completely encapsulating and sealing the hip joint encoder using an "m"-shaped adhesive sealing process. This not only completely isolates external explosive gases from contact with internal circuit components that might generate minute electrical sparks, but also effectively prevents the intrusion of moisture and dust. Thus, the entire measurement unit meets both the IIC-T6 explosion-proof rating and the IP66 protection rating requirements. In summary, this hip joint design highly integrates power transmission, motion feedback, and intrinsically safe protection into a compact unit, providing a key technological foundation for ensuring high-precision, high-reliability intelligent operation of the hydraulic quadruped robot in flammable and explosive environments.

[0047] Specific implementation method four: Combination Figures 1 to 7 This embodiment describes a pitch drive unit comprising a pitch hydraulic cylinder 50, a pitch two-force bar shaft 4, a pitch slider 51, a hip two-force bar 2, a hip two-force bar shaft 3, a slide rail 52, and a pitch block. The pitch hydraulic cylinder 50 is mounted along the length of the thigh skeleton 5, with its extended end facing the hip joint. The slide rail 52 is mounted in front of the extended end of the pitch hydraulic cylinder 50. One end of the hip two-force bar 2 is connected to the extended end of the pitch hydraulic cylinder 50 via the pitch two-force bar shaft 4, and the other end of the hip two-force bar 2 is connected to the pitch block mounted on the hip pitch-pitch joint 10 via the hip two-force bar shaft 3. The lower end of the pitch slider 51 is slidably mounted on the slide rail 52, and the upper end of the pitch slider 51 is connected to the extended end of the pitch hydraulic cylinder 50.

[0048] This implementation efficiently and precisely converts the high-pressure fluid energy of the pitch hydraulic cylinder into high-torque rotational motion of the hip joint, and optimizes force transmission through ingenious mechanical structure design, ensuring smooth movement and structural reliability under heavy loads. Specifically, the pitch hydraulic cylinder, installed within the thigh skeleton, serves as the power source. The linear extension and retraction of its piston rod is converted into rotational output through a compound linkage mechanism: the extended end of the piston rod is hinged to one end of the hip two-force rod via the pitch two-force rod shaft, while the other end of the hip two-force rod is connected to the pitch block fixed to the hip pitch-pitch joint via the hip two-force rod shaft, forming a stable torque output structure. This design efficiently transmits the linear thrust of the hydraulic cylinder along the two-force rod direction to the hip joint axis, significantly increasing the lever arm, thereby amplifying the joint output torque without increasing the size of the hydraulic cylinder, meeting the requirements for high-strength torque.

[0049] Furthermore, the sliding pair formed by the pitch slider and the slide rail provides precise radial constraint and guidance for the movement of the hydraulic cylinder piston rod, effectively counteracting the lateral load borne by the hydraulic cylinder during operation and preventing piston rod jamming or uneven wear. This ensures both the lifespan of the hydraulic cylinder and the positional accuracy of the joint movement. The entire drive unit is integrated inside the thigh skeleton, protecting the precision components from external impacts and contamination, and achieving high power density of the leg motion system through a compact layout. This mechanism ultimately gives the robot's hip joint strong, controllable, and durable pitch freedom drive capability, providing a crucial power foundation for dynamic behaviors such as climbing and obstacle crossing under heavy loads.

[0050] Specific Implementation Method Five: Combining Figures 4 to 8 This embodiment describes a knee joint including a knee joint shaft 21, a knee joint magnet mounting base 20, a magnet 19, a magnetic encoder 18, and a knee joint bearing mounting base 17. The knee joint shaft 21 is rotatably mounted on the lower part of the thigh frame 5. The magnet 19 is embedded in the end of the knee joint shaft 21 through the knee joint magnet mounting base 20. A knee joint sealing cover is mounted on the magnet 19. The magnetic encoder 18 is mounted on the knee joint sealing cover outside the magnet 19 and is encapsulated by the knee joint bearing mounting base 17.

[0051] This design completely isolates external explosive gases from the circuitry inside the encoder, which could potentially generate minute electrical sparks, thus eliminating the risk of ignition. It effectively resists the intrusion of dust, moisture, and even liquid media, ensuring the long-term measurement accuracy and lifespan of the sensor under harsh conditions such as oil and chemical environments. It also enhances overall shock resistance, preventing connection failures during dynamic running or heavy impacts by the robot. The entire system deeply integrates sensing and explosion-proof functions, enabling the knee joint unit to simultaneously meet the stringent requirements of both explosion-proof and protection levels without the need for a bulky explosion-proof enclosure.

[0052] Specific Implementation Method Six: Combination Figure 5 and Figure 7 This embodiment describes a knee joint bearing mounting base 17 that is encapsulated using an adhesive-sealed explosion-proof method.

[0053] This embodiment uses a "knee joint bearing mounting base" to form a sealed cavity, injects epoxy resin sealant, and completely encapsulates and cures precision electronic components such as magnetic encoders. It can achieve: (1) Isolation: completely isolate external explosive gases from internal circuits that may generate sparks. (2) Suffocation: even if the internal components generate tiny sparks, they will be suffocated by the sealant and cannot ignite the external environment.

[0054] In practical use, the sealant length should be greater than or equal to 20mm, and the cross-sectional area of ​​the potting compound should be greater than or equal to 20%.

[0055] Specific implementation method seven: Combination Figure 2 In this embodiment, the knee joint further includes a crank-slider pitch mechanism, which includes a knee joint hydraulic cylinder 53, a knee joint slide rail 54, a knee joint slider 55, and a knee joint two-force bar 56. The knee joint hydraulic cylinder 53 is installed along the length of the thigh frame 5, with its extension end facing the knee joint side. The knee joint slide rail 54 is installed on the thigh frame 5. The extension end of the knee joint hydraulic cylinder 53 is connected to one end of the knee joint two-force bar 56 through the knee joint slider 55. The knee joint slider 55 is slidably installed on the knee joint slide rail 54, and the other end of the knee joint two-force bar 56 is rotatably connected to the upper part of the lower leg segment.

[0056] This configuration efficiently converts the linear thrust of the knee joint hydraulic cylinder into a large-amplitude pitching motion of the lower leg segment. Optimized mechanical structure design achieves a power amplification effect and motion stability, ultimately providing the robot with powerful and controllable knee joint actuation capabilities. Specifically, the knee joint hydraulic cylinder, installed within the thigh skeleton, serves as the power source. The linear motion of its piston rod is precisely guided by a sliding pair formed by the knee joint slider and the knee joint slide rail, effectively offsetting any lateral loads the hydraulic cylinder may experience during operation. This prevents piston rod wear and jamming, significantly improving the cylinder's lifespan and motion accuracy. The extended end of the piston rod is hinged to one end of the knee joint's two-force bar, while the other end of the two-force bar is rotaryly connected to the upper part of the lower leg segment, converting the linear output of the hydraulic cylinder into rotational motion of the lower leg segment around the knee joint axis.

[0057] The crank-slider mechanism fully leverages the force transmission characteristics of a two-force bar. Through a reasonable arrangement of rod lengths and hinge points, it achieves a good lever arm effect within the knee joint's range of motion, effectively amplifying the hydraulic cylinder's output force and converting it into a large torque at the joint end. This meets the stringent torque requirements of the knee joint during obstacle crossing, hill climbing, and heavy-load movements. Furthermore, the entire drive unit is fully integrated within the thigh frame, resulting in a compact and space-saving design. It also avoids contamination and impact from the complex external environment on the kinematic pairs, further enhancing the system's reliability and environmental adaptability.

[0058] Specific implementation method eight: Combination Figure 2 This embodiment describes a lower leg segment that includes a lower leg aluminum component 57 and a lower leg end connector. The upper part of the lower leg aluminum component 57 is connected to the knee joint, and the other end of the knee joint two-force bar 56 is connected to the lower leg aluminum component 57, which drives the lower leg aluminum component 57 to tilt. The lower leg end connector is detachably installed on the lower part of the lower leg aluminum component 57.

[0059] This embodiment, as the core transmission component connecting the knee joint and the actuator, achieves efficient conversion of motion functions through a modular interface, and achieves an optimal balance between lightweight and high strength. Specifically, the aluminum lower leg component serves as a load-bearing skeleton, with its upper end hinged to the thigh section via the knee joint axis, and simultaneously forming a power connection point with the end of the knee joint's two-force bar. This converts the torque generated by the crank-slider mechanism driven by the hydraulic cylinder into the pitching motion of the lower leg around the knee joint axis, forming a complete power transmission chain. The standardized mechanical interface designed at its lower part enables rapid installation and positioning of the lower leg end connector through quick-release locking devices (such as pins, clamps, or high-strength bolts).

[0060] Specific Implementation Method Nine: Combining Figure 8 and Figure 9 This embodiment describes a lower leg end connector that is either a foot-type module or a wheel-type module.

[0061] When the lower leg end connector is a foot-type module, the foot-type module includes a foot body 58 and a soft pad 59. The upper part of the foot body 58 is detachably mounted on the lower leg aluminum part 57 through a mechanical interface, and the soft pad 59 is mounted on the lower end of the foot body 58.

[0062] The foot body 58 is made of high-strength nylon as the skeleton, and the sole is printed with rubber to increase friction. The two are bonded together with glue.

[0063] Specific Implementation Method Ten: Combining Figure 8 and Figure 9 This embodiment describes a quadruped robot, which includes a robot body and four modular wheel-leg switching structures installed at the four corners of the robot body.

[0064] This implementation method integrates a biomimetic quadrupedal layout with a wheel-leg dual-modality design to create an all-around mobile platform that balances extreme terrain mobility, high-speed maneuverability, heavy-load transport capacity, and intrinsically safe explosion-proof characteristics. The four wheel-leg switching structures are symmetrically distributed at the four corners of the robot's main body, forming a stable quadrupedal support configuration. This layout not only mimics the motion stability of mammals in nature, ensuring the robot's center of gravity remains within the polygonal support area, guaranteeing static and dynamic stability when moving on unstructured terrain (such as slopes and gravel surfaces), but more importantly, each leg structure, as an independent intelligent motion unit, possesses three degrees of freedom: hip pitch / lateral swing and knee flexion / extension. Through the coordinated planning of the central control system, it can comprehensively achieve longitudinal walking, lateral movement, turning in place, and even complex gaits (such as trotting and jumping), thus giving the robot superior terrain adaptability beyond wheeled or tracked platforms.

[0065] Combination Figures 1 to 9 Explanation of the working principle of this invention:

[0066] The robot's internal hydraulic power unit and battery system provide high-pressure hydraulic fluid and electricity, respectively. The high-pressure hydraulic fluid is precisely delivered to the hydraulic cylinders of each joint through 3D-printed ribbed hydraulic circuits within the thigh skeleton and hollow channels in the hip pitch-hinge joint. The linear motion of the piston rod of the pitch hydraulic cylinder drives the hip lever via the pitch lever axis, which in turn drives the pitch block fixed to the hip pitch-hinge joint, ultimately translating into pitch rotation of the hip joint. Simultaneously, an independent hydraulic circuit drives the lateral pitch-hinge adapter to achieve lateral hip joint movement. The extension and retraction of the knee joint hydraulic cylinder, on the other hand, drives the lower leg aluminum component to rotate around the knee joint axis via the knee lever, achieving knee flexion and extension.

[0067] During movement, the magnetic encoder detects changes in the magnetic field of a magnet fixed to the end of the knee joint shaft, providing real-time feedback on the joint angle. The signal is processed by circuitry encapsulated within the knee joint bearing mounting housing before being uploaded to the controller. A pressure sensor simultaneously monitors hydraulic pressure to sense ground forces. The controller integrates environmental data and joint status, using a closed-loop algorithm to adjust the opening of the hydraulic servo valve in real-time, achieving precise foot trajectory tracking and body posture stability.

[0068] When switching movement modes is required, the lower leg end connectors can be quickly replaced: with the leg module installed, the robot adapts to rugged terrain with a multi-degree-of-freedom bionic gait; after switching to the wheel module, the hydraulic circuit switches to drive the wheel hub motors, and the robot enters a four-wheel high-speed rolling mode, automatically selecting the optimal mode through terrain recognition sensors and intelligent algorithms. All power and sensing components are based on hydraulic drive and explosion-proof sealing design, ensuring no spark risk in the IIC-T6 environment, thereby enabling autonomous inspection, heavy-duty transportation, and emergency operations in high-risk scenarios.

[0069] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A modular wheel-leg switching structure for explosion-proof environments, characterized in that: It includes a lower leg segment, an explosion-proof thigh segment, and a knee joint. The thigh segment and the lower leg segment are hinged together by the knee joint. The lower leg segment is a modular structure that can be quickly replaced. The lower part of the lower leg segment is connected to a foot module or a wheel module.

2. The modular wheel-foot switching leg structure for explosion-proof environments according to claim 1, characterized in that: The thigh segment includes a thigh skeleton (5), a hip joint, a lateral tilt-tilt adapter (1), and a pitch drive unit. The thigh skeleton (5) is integrally formed by 3D printing, and the thigh skeleton (5) is provided with ribs for conveying hydraulic oil. The hip joint is installed on the upper part of the thigh skeleton (5), and the hip joint is connected to the robot body through the lateral tilt-tilt adapter (1). The robot body drives the lateral tilt-tilt adapter (1) through a lateral tilt cylinder, and the hip joint is driven by a linear cylinder to achieve pitch. The pitch drive unit is installed inside the thigh skeleton (5) and drives the hip joint to rotate hydraulically to achieve pitch.

3. The modular wheel-foot switching leg structure for explosion-proof environments according to claim 2, characterized in that: The hip joint includes a hip magnet mount (6), a hip joint encoder (40), a hip joint encoder sealing cover (7), and a hip pitching oil-running joint (10); the hip pitching oil-running joint (10) is rotatably mounted on the thigh skeleton (5) in the width direction, the hip magnet mount (6) is mounted on the thigh skeleton (5) on the outside of the hip pitching oil-running joint (10), and the hip joint encoder (40) is mounted on the end of the hip magnet mount (6) and sealed and fixed by the hip joint encoder sealing cover (7).

4. A modular wheel-foot switching leg structure for explosion-proof environments according to claim 3, characterized in that: The pitch drive unit includes a pitch hydraulic cylinder (50), a pitch two-force shaft (4), a pitch slider (51), a hip two-force shaft (2), a hip two-force shaft (3), a slide rail (52), and a pitch block. The pitch hydraulic cylinder (50) is installed along the length of the thigh skeleton (5), and the extended end of the pitch hydraulic cylinder (50) faces the hip joint. The slide rail (52) is installed in front of the extended end of the pitch hydraulic cylinder (50). One end of the hip two-force bar (2) is connected to the extended end of the pitch hydraulic cylinder (50) through the pitch two-force bar shaft (4). The other end of the hip two-force bar (2) is connected to the pitch block installed on the hip pitch oil-running joint (10) through the hip two-force bar shaft (3). The lower end of the pitch slider (51) is slidably installed on the slide rail (52), and the upper end of the pitch slider (51) is connected to the extended end of the pitch hydraulic cylinder (50).

5. A modular wheel-foot switching leg structure for explosion-proof environments according to claim 4, characterized in that: The knee joint includes a knee joint shaft (21), a knee joint magnet mount (20), a magnet (19), a magnetic encoder (18), and a knee joint bearing mount (17). The knee joint shaft (21) is rotatably mounted on the lower part of the thigh skeleton (5). The magnet (19) is embedded in the end of the knee joint shaft (21) through the knee joint magnet mount (20). The knee joint sealing cover is mounted on the magnet (19). The magnetic encoder (18) is mounted on the knee joint sealing cover outside the magnet (19) and encapsulated by the knee joint bearing mount (17).

6. A modular wheel-foot switching leg structure for explosion-proof environments according to claim 5, characterized in that: The knee joint bearing mounting base (17) is encapsulated using an explosion-proof adhesive sealing method.

7. A modular wheel-foot switching leg structure for explosion-proof environments according to claim 6, characterized in that: The knee joint also includes a crank-slider pitch mechanism, which includes a knee joint hydraulic cylinder (53), a knee joint slide rail (54), a knee joint slider (55), and a knee joint two-force bar (56). The knee joint hydraulic cylinder (53) is installed along the length of the thigh frame (5), and the telescopic end of the knee joint hydraulic cylinder (53) faces the knee joint side. The knee joint slide rail (54) is installed on the thigh frame (5). The telescopic end of the knee joint hydraulic cylinder (53) is connected to one end of the knee joint two-force bar (56) through the knee joint slider (55). The knee joint slider (55) is slidably installed on the knee joint slide rail (54), and the other end of the knee joint two-force bar (56) is rotatably connected to the upper part of the lower leg segment.

8. A modular wheel-leg switching structure for explosion-proof environments according to claim 1, characterized in that: The lower leg segment includes a lower leg aluminum piece (57) and a lower leg end connector. The upper part of the lower leg aluminum piece (57) is connected to the knee joint, and the other end of the knee joint two-force bar (56) is connected to the lower leg aluminum piece (57), which drives the lower leg aluminum piece (57) to achieve pitch. The lower leg end connector can be detachably installed on the lower part of the lower leg aluminum piece (57).

9. A modular wheel-foot switching leg structure for explosion-proof environments according to claim 8, characterized in that: The lower leg end connector is either a foot-type module or a wheel-type module.

10. A quadruped robot using a modular wheel-leg switching leg structure for explosion-proof environments as described in any one of claims 1-9, characterized in that: It includes a robot body and four modular wheel-foot switching leg structures, which are installed at the four corners of the robot body.

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