Double-foot wheel leg self-balancing robot

Abstract

The utility model provides a double-foot wheel leg self-balancing robot, and belongs to the technical field of robots. The self-balancing robot comprises a trunk integration assembly, a control system is integrated in the trunk integration assembly, and the trunk integration assembly is used for collecting posture data of the robot in real time, outputting control instructions, achieving self-balancing adjustment of the robot and guaranteeing dynamic stability of the whole robot. The wheel and leg modules are located on the two sides of the bottom of the robot, and each wheel and leg module comprises a pair of tandem type four-connecting-rod leg structures and a hub driving assembly; and the driving module is arranged in the trunk integrated assembly, is connected with the wheel-leg module through a rope transmission module, is used for driving the wheel-leg module to bend and stretch legs, and is matched with a hub driving assembly, so that the robot has dual capabilities of wheel-type movement and leg-type obstacle crossing. According to the utility model, the self-stability of the robot and the movement capability of the robot under complex terrains are improved by adopting rope transmission and a tandem four-connecting-rod leg structure.

Description

Technical Field

[0001] The utility model relates to the technical field of robots, in particular to a bipedal wheel-leg self-balancing robot. Background Art

[0002] As the application of service robots, scientific research robots, and specialized robots continues to expand, the versatility and adaptability of traditional wheeled or legged robots in complex terrains face significant challenges. This is especially true in scenarios with varied terrain, limited space, and the need for dynamic and stable operation. Existing robots struggle to balance flexibility, stability, and lightweight construction.

[0003] Some self-balancing robots currently on the market use rigid legs and gear or chain transmissions. These solutions present technical challenges such as structural complexity, high space requirements, poor stability, heavy weight, difficult maintenance, and significant transmission noise. In bipedal configurations, the leg drive system's bulk often compromises center of gravity control accuracy and overall balance performance.

[0004] Therefore, there is an urgent need to develop a bipedal wheel-legged self-balancing robot with a compact structure, simple drive, excellent stability and adaptability to a variety of complex terrains, so as to comprehensively improve the robot's obstacle crossing ability, self-stabilization performance and platform application value. Utility Model Content

[0005] In view of this, in order to solve the technical problems of poor self-stabilization performance and obstacle crossing ability of the current self-balancing robots that generally adopt rigid leg structures and gear or chain transmission devices, the utility model provides a bipedal wheel-legged self-balancing robot, which improves the robot's self-stabilization performance and movement ability in complex terrain by adopting rope transmission and a series four-bar linkage leg structure.

[0006] To achieve the above objectives, the present invention provides the following technical solutions:

[0007] A bipedal wheel-legged self-balancing robot comprising:

[0008] The trunk integrated component integrates a control system for real-time acquisition of robot posture data and output of control instructions to achieve self-balancing adjustment of the robot and ensure the dynamic stability of the entire robot.

[0009] Wheel-leg modules are located on both sides of the bottom of the robot. Each wheel-leg module contains a pair of serial four-link leg structures and a wheel hub drive assembly.

[0010] The driving module is arranged in the torso integrated component and is connected to the wheel-leg module through a rope transmission module. It is used to drive the wheel-leg module to realize the flexion and extension of the legs. In conjunction with the wheel hub drive component, the robot has the dual capabilities of wheeled movement and leg-based obstacle crossing.

[0011] Preferably, the rope transmission module comprises:

[0012] A small rotating drum coaxially connected to the output shaft end of the joint motor of the driving module;

[0013] A large rotating drum is nested outside the power output shaft and is coaxially arranged with the power arm of the series four-link leg structure;

[0014] The small rotating drum transmits the rotational power of the joint motor to the large rotating drum through a rope. The large rotating drum is used to receive the rope tension transmitted by the small rotating drum to drive the power arm to move.

[0015] Preferably, a first thread groove and a guide hole are provided on the surface of the small rotating drum, which are used for securely winding the rope and adjusting the rope entry angle respectively;

[0016] The large rotating drum is provided with a second thread groove for winding the rope and forming a closed-loop transmission path.

[0017] Preferably, the second thread groove is a double-track thread groove, which is used for bidirectional rope winding and forming a closed-loop transmission path.

[0018] Preferably, a threaded hole is provided in the small rotating drum for screws to pass through, the purpose of which is to improve the strength of the small rotating drum, transfer the force it receives to the four through screws, and fasten it to the output shaft end of the joint motor through four fastening screws on the end outward flange.

[0019] Preferably, the large rotating drum comprises:

[0020] The inner large rotating drum serves as the power output shaft, and the L1 power arm is sleeved and fixed on the inner large rotating drum;

[0021] The outer large rotating drum is nested on the outside of the inner large rotating drum, forming a coaxial nested layout of "inner shaft-outer drum".

[0022] Preferably, the inner large rotating drum and the outer large rotating drum are connected to the tensioning device through an annular screw, which is used to adjust the tension of the rope and realize "soft limit" of the rope;

[0023] The outer large rotating drum is provided with a limit groove for achieving "hard limit" on the rope.

[0024] Preferably, the free rotation angle of the inner large rotating drum and the outer large rotating drum is 0-150°.

[0025] Preferably, the wheel hub drive assembly comprises:

[0026] On-wheel motors,

[0027] a wheel hub, rotatably connected to the end of the series four-link leg structure and directly connected to the on-wheel motor;

[0028] The tire is mounted on the outside of the wheel hub and directly contacts the ground.

[0029] Preferably, the outer surface of the hub is provided with longitudinal lines, and the tire is a honeycomb solid tire.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) Rope transmission system: low wear, low noise, high flexibility, light weight

[0032] Traditional gear / chain transmission has technical problems such as complex structure, rapid wear and high noise. This utility model optimizes it through a flexible rope transmission system (small rotating drum + large rotating drum), as follows:

[0033] The surface of the small rotating drum is provided with thread grooves and guide holes to guide the rope to be wound and fixed and to adjust the angle (the rope passes through the guide hole and is arranged along the thread groove) to prevent the rope from sliding;

[0034] The large rotating drum is equipped with double matching thread grooves to form a closed-loop transmission path, ensuring stable rope retraction and release;

[0035] The tensioning device is connected to the large rotating drum through a ring screw and is used to adjust the tightness of the rope and maintain the transmission tension.

[0036] Advantages: Rope transmission replaces rigid transmission, significantly reducing mechanical wear and operating noise, while improving transmission flexibility (the rope can deform slightly to absorb impact), making it suitable for long-term operations in complex terrain.

[0037] (2) Series four-link wheel-leg structure: taking into account both mobility and obstacle-crossing capabilities

[0038] The robot uses a bipedal wheel-leg module to achieve the fusion of wheeled and legged movements:

[0039] The wheel-leg modules are located on both sides of the bottom and connected to the trunk through a carbon fiber frame. The tandem four-link leg structure is connected in series above the wheel foot, and the leg flexion and extension can be achieved by changing the joint angle.

[0040] The wheel feet (wheel hub + honeycomb solid tire) provide efficient wheeled mobility on flat terrain, and the serial four-link leg structure is driven by joints to achieve actions such as leg lifting and obstacle crossing (such as climbing stairs and crossing ravines).

[0041] Advantages: Compared with single wheeled or legged robots, this new robot takes into account both the mobility efficiency on flat terrain (wheeled) and the passability on complex terrain (legged), and its obstacle crossing ability is significantly improved.

[0042] (3) Limiting design on the inner and outer large rotating drums: high degree of freedom and motion controllability

[0043] The large rotating drum adopts a double limit structure of inner large rotating drum soft limit + outer large rotating drum hard limit:

[0044] The large inner rotating drum serves as the power output shaft, and its excessive rotation is limited by the tensioned rope (soft limit), avoiding transmission failure caused by rope slack;

[0045] The outer large rotating drum is nested outside the power shaft (inner large rotating drum) and cooperates with the power shaft through the limit slot to directly limit its rotation angle to 150° (hard limit), ensuring that the joint movement does not exceed the gait control range.

[0046] Advantages: The dual-limit design not only ensures high degrees of freedom of the joint (150° rotation range), but also prevents loss of control through dual constraints of soft and hard limits, thereby improving the accuracy of gait control and structural reliability.

[0047] (4) Anti-slip design of wheels and feet: Detailed optimization of mobility reliability

[0048] The wheel foot part uses 3D printed wheels + honeycomb solid tires, and the outer surface of the wheel is covered with longitudinal lines:

[0049] The wheel hub is directly connected to the on-wheel motor and is integrally formed through 3D printing, resulting in high structural strength and low cost.

[0050] The longitudinal grooves increase the contact friction between the wheel and the tire, preventing the tire from slipping when driving (especially on wet or soft surfaces).

[0051] Advantages: The anti-slip design improves the reliability of wheeled mobility, avoids power waste or posture loss caused by tire idling, and adapts to more complex ground scenarios (such as mud and sand).

[0052] In summary, the utility model has formed significant technical advantages in transmission efficiency, movement flexibility, self-balancing stability, terrain adaptability, etc. through core structural innovations such as rope transmission module, series four-link leg structure, and double-limit rotating drum. It is particularly suitable for scenarios such as geographical exploration, disaster relief, and material handling that require high robot operation capabilities in complex terrain. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0054] Figure 2 Schematic diagram of the series four-link leg structure;

[0055] Figure 3This is a schematic diagram of the small rotating drum structure of the rope transmission module and its partial enlarged view;

[0056] Figure 4 It is a schematic diagram of the structure of the large rotating drum and its partial enlarged diagram;

[0057] Figure 5 This is a schematic diagram of the assembly of the inner and outer large rotating drums and the tensioning device;

[0058] Figure 6 This is the internal integrated structure layout diagram of the main control trunk;

[0059] In the figure, 1. trunk integrated assembly; 2. wheel-leg module; 21. serial four-link leg structure; 211. power arm; 212. transmission member; 213. driven member; 214. large driving member; 22. wheel hub drive assembly; 221. wheel motor; 222. wheel hub; 223. tire; 3. drive module; 4. rope transmission module; 41. small rotating drum; 411. first thread groove; 412. guide hole; 413. threaded hole; 42. large rotating drum; 421. second thread groove; 422. inner large rotating drum; 423. outer large rotating drum; 4231. limit groove; 424. tensioning device. DETAILED DESCRIPTION

[0060] The following will combine the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all the embodiments. All other embodiments obtained by ordinary technicians in this field without making creative work based on the embodiments in the present invention fall within the scope of protection of the present invention.

[0061] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0062] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "mounted / connected," and "connected" should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be internal communication between two components. For those skilled in the art, the specific meanings of the above terms in this utility model can be understood according to the specific circumstances.

[0063] like Figure 1 As shown, the utility model provides a bipedal wheel-leg self-balancing robot, comprising:

[0064] The trunk integrated component 1 is integrated with a control system for real-time acquisition of robot posture data and output of control instructions to achieve self-balancing adjustment of the robot and ensure the dynamic stability of the entire robot. In the present invention, the trunk integrated component 1 is preferably an integrated setting. The control system in the trunk integrated component 1 can be controlled by a conventional control system in the art, and there is no special requirement for this. Figure 6 As shown, in the present invention, an embodiment of the control system is exemplarily shown, which is as follows:

[0065] 1. The control system can be integrated with the following components (selectable according to actual needs):

[0066] Main control and drive system

[0067] Raspberry Pi 4B main control unit: As the "brain" of the robot, it is responsible for posture control algorithm calculation, sensor data processing and motor command output.

[0068] Pi3hat expansion board: connects to the Raspberry Pi, provides a CAN bus interface, and enables high-speed communication with the MJBots driver board (supports the Moteus motor control protocol).

[0069] MJBots driver board: directly controls the operation of the joint motor of the drive module 3 (preferably a Moteus brushless servo motor), receives instructions from the Raspberry Pi and adjusts the motor speed and torque.

[0070] Energy and distribution systems

[0071] Battery assembly: Provides power for the entire machine, installed below the center of gravity of the torso (bottom compartment), using lightweight, high-capacity batteries.

[0072] Power distribution board: distributes the power output of the battery to various subsystems such as the Raspberry Pi, driver board, and sensors to ensure voltage stability.

[0073] Structure and fixings

[0074] 3D-printed parts: These form the main frame of the torso, offering a lightweight and customizable design to accommodate the layout requirements of internal components.

[0075] Carbon fiber plate: used in the series four-link leg structure to enhance structural strength while achieving lightweight.

[0076] PC packaging board: covers the outside of the trunk and protects internal components from external dust and vibration.

[0077] Stud and compartment structure: The control board is fixed to the middle compartment of the torso by studs to ensure the flatness and stability of the circuit board; the components are arranged in layers (such as batteries at the bottom and main control in the middle) to avoid cross-wiring.

[0078] Wire ducts are located between the internal compartments and studs of the trunk integrated assembly and run along the inner wall of the frame. They are used to organize the wires connecting the subsystems, such as the communication lines between the main control unit and the driver board, and the power supply lines of the power distribution board, to avoid cross-entanglement of the lines; they reduce electromagnetic interference through physical isolation and ensure the stability of signal transmission.

[0079] 2. Functions

[0080] Centralized control and signal transmission: The Raspberry Pi main control communicates with the driver board through the Pi3 Hat expansion board, collects robot posture data (such as tilt angle and joint position) in real time, and outputs control commands to the joint motors to achieve gait adjustment and self-balancing functions.

[0081] Power distribution and stable supply

[0082] The power distribution board distributes battery power to various electronic components (such as high-power motor drives and low-power sensors) as needed, ensuring system voltage stability and avoiding control failures caused by power fluctuations.

[0083] Structural protection and earthquake resistance

[0084] The 3D printed frame and carbon fiber plate provide rigid support to prevent internal components from shifting due to external impact;

[0085] The control board is fixed in the compartment by studs to reduce the impact of vibration during robot movement on the circuit board (such as preventing solder joints from falling off).

[0086] The encoder magnet, built into the output shaft of the driver module's joint motor (such as a Moteus brushless servo motor), detects the motor's rotation angle and speed in real time and transmits this data to the Raspberry Pi main control unit via the Pi3 Hat expansion board, enabling closed-loop motor control. Combined with posture sensor data, it precisely adjusts the flexion and extension angles of the wheel-leg module to ensure self-balancing and gait control accuracy.

[0087] Center of gravity optimization and self-balancing support

[0088] The battery is located below the center of gravity and installed in the battery compartment at the bottom of the trunk integrated component, which lowers the center of gravity of the entire machine. Combined with the Raspberry Pi's posture control algorithm, it significantly improves the robot's anti-interference ability during dynamic movements (such as walking and obstacle crossing).

[0089] 3. Advantages

[0090] High space utilization: The integrated structure centralizes the main control, drive, battery and other components in the middle of the torso, avoiding the space waste caused by the dispersed installation of traditional robots (such as the motor and control board are separated in the legs and torso), and reserving space for subsequent functional expansion (such as the installation of sensors and communication modules).

[0091] Balancing lightweight and structural stability: 3D-printed parts, carbon fiber panels, and other lightweight materials are used to reduce overall weight while ensuring structural strength (for example, the hollowed-out design of the printed trunk provides a cooling duct for the driver board while reducing overall weight), thereby reducing energy consumption.

[0092] The combination of carbon fiber boards and PC boards not only enhances impact resistance but also avoids the high weight problem of metal structures.

[0093] Easy maintenance and debugging: The modular layout (such as the control panel fixed by studs and the unified management of cables) facilitates quick disassembly and maintenance; the low-mounted battery design (bottom compartment) simplifies the replacement process and reduces maintenance costs.

[0094] Enhanced self-balancing performance: The synergy between the downward shift of the battery's center of gravity and the integrated trunk design makes it easier for the robot to maintain balance in complex terrain (such as slopes and uneven surfaces), reducing the risk of tipping over due to center of gravity shift.

[0095] Those skilled in the art may select the above-mentioned control system provided by the present invention or a conventional control system in the prior art according to actual needs. There are no special requirements in the present invention.

[0096] The wheel-leg modules 2 are located on either side of the robot's base. Each wheel-leg module 2 comprises a pair of tandem four-link leg structures 21 and a wheel hub drive assembly 22. They directly contact the ground and are responsible for walking and overcoming obstacles. The wheel hub drive assembly 22 is mounted at the ends of the tandem four-link leg structures 21. The tandem four-link leg structures 21 are preferably connected to the bottom of the trunk integrated assembly 1 via a carbon fiber support frame, forming the robot's "lower limbs." The wheel hub drive assembly 22 is connected to the ends of the tandem four-link leg structures 21 via on-wheel motors 221, wheels, and tires 223, forming the "wheel feet." The tandem four-link leg structures 21 achieve leg flexion and extension through changes in joint angles. Combined with the wheel hub drive, the robot possesses the dual capabilities of wheeled locomotion (on flat terrain) and legged obstacle overcoming (on complex terrain), improving its terrain adaptability.

[0097] The driving module 3 is arranged in the trunk integrated component 1, and is connected to the wheel-leg module 2 through the rope transmission module 4. It is used to drive the wheel-leg module 2 to realize the flexion and extension movement of the legs. In conjunction with the wheel hub drive component 22, the robot has the dual capabilities of wheeled movement and leg-based obstacle crossing.

[0098] like Figure 2 As shown, the present invention provides an embodiment of a tandem four-link leg structure 21, which is enclosed by a power arm 211, a transmission member 212, a driven member 213, and a large driving member 214. The power arm 211 is sleeved and fixed on the inner large rotating drum, and the large driving member 214 is sleeved and fixed on the outer large rotating drum. The power arm 211, the transmission member 212, the driven member 213, and the large driving member 214 are sequentially connected to form the tandem four-link leg structure 21.

[0099] It is connected to the joint motor in the drive module 3 through a rope to achieve angle change and action execution; different from the traditional method of using gears or chains, the utility model uses high-strength wear-resistant ropes for transmission, which not only improves the transmission efficiency, but also effectively reduces mechanical noise and wear.

[0100] like Figure 3-5 As shown, the present invention provides a specific implementation of the rope transmission module 4, which is as follows:

[0101] The rope transmission module 4 includes:

[0102] The small rotating drum 41 is coaxially connected to the output shaft end of the joint motor of the driving module 3 .

[0103] The large rotating drum 42 is nested outside the power output shaft and is coaxially arranged with the power arm 211 of the serial four-link leg structure 21 .

[0104] The small rotating drum 41 serves as the driven wheel of the rope transmission module 4, transmitting the rotational power of the joint motor to the large rotating drum 42 through the rope. The large rotating drum 42 serves as the driving wheel, receiving the rope tension transmitted by the small rotating drum 41, and driving the power arm 211 to move.

[0105] In this utility model, the surface of the small rotating drum 41 is provided with a first threaded groove 411 and a guide hole 412 (which guides the rope and adjusts the rope entry angle). These are used for stable rope winding (the rope passes through the guide hole 412 and winds along the first threaded groove 411) and for adjusting the rope entry angle. The first threaded groove 411 stabilizes the rope's trajectory, preventing slippage and tangled winding. The guide hole 412 allows the rope to pass through, guides the rope, and adjusts the rope entry angle.

[0106] The large rotating drum 42 is provided with a second thread groove 421 for winding a rope and forming a closed-loop transmission path.

[0107] In the present invention, the second thread groove 421 is a double-track thread groove, which is used for bidirectional rope winding and forming a closed-loop transmission path.

[0108] In the present invention, a threaded hole 413 is provided in the small rotating drum 41 for screws to pass through and be fastened to the output shaft end of the joint motor, thereby improving the strength of the small rotating drum, transferring the force received to the four through screws, and fastening the drum to the output shaft end of the joint motor through four fastening screws on the end outward flange.

[0109] Simultaneously, the opening of the screw hole can also reduce deadweight. In the present utility model, it is preferably fastened to the output shaft end of the joint motor by 4 screws.

[0110] In the present invention, the large rotating drum 42 includes:

[0111] The inner large rotating drum 422 serves as a power output shaft, and the power arm 211 is sleeved and fixed on the inner large rotating drum 422 to drive the power arm 211 to move.

[0112] The outer large rotating drum 423 is nested on the outside of the inner large rotating drum 422, forming a coaxial nested layout of "inner shaft-outer drum", with a compact and stable structure.

[0113] In this utility model, the inner and outer large rotating drums 422 and 423 are connected to the tensioning device 424 via annular screws (preferably M4 nuts). These are used to adjust the rope tension, providing a "soft limit" on the rope (limiting excessive rotation after the rope is tensioned), ensuring a controllable rotation range. For example, tightening the annular screw at the end of the rope to tighten the rope, and tensioning can be achieved by simply rotating the nut below the sleeve.

[0114] The outer large rotating drum 423 is provided with a limiting groove 4231 for achieving "hard limiting" of the rope.

[0115] In the present invention, the free rotation angle of the inner large rotating drum 422 and the outer large rotating drum 423 is 0-150°, so as to avoid exceeding the angle range required for gait control.

[0116] The coaxial nesting of the inner and outer large rotating drums 422 and 423, with complementary stoppers, ensures stable power transmission (the inner large rotating drum 422 acts as the active axis driving the power arm 211). The hard stoppers on the outer large rotating drum 423 also control joint rotation angles, meeting the precise control requirements for high-degree-of-freedom gaits. The stopper design (soft and hard) on both inner and outer large rotating drums 423 ensures controllable joint angles during transmission, meeting the requirements for high-degree-of-freedom gaits.

[0117] like Figure 5 As shown, in the present invention, the wheel hub drive assembly 22 includes:

[0118] The on-wheel motor 221 is located at the end of the series four-link leg structure 21 .

[0119] The wheel hub 222 is rotatably connected to the end of the tandem four-bar linkage leg structure 21 and is directly connected to the on-wheel motor 221. The wheel hub 222 is preferably formed in one piece by 3D printing and is securely connected to the output shaft of the on-wheel motor 221 through an inner hole on the wheel hub 222. The outer surface of the wheel hub 222 is covered with longitudinal grooves and contacts the honeycomb solid tire 223 described below, which is used to transmit the driving force of the on-wheel motor 221 to the tire 223 to achieve wheeled movement. The surface grooves increase friction with the tire 223 to prevent slipping.

[0120] Tire 223 fits over the wheel hub, directly contacting the ground. Preferred is a solid honeycomb tire 223. It is secured to the hub via longitudinal grooves on the hub surface, without additional fasteners. It provides ground friction and supports the robot's weight. Its solid honeycomb structure enhances impact resistance and adapts to complex terrain.

[0121] In summary, the self-balancing robot provided by this utility model achieves efficient component integration through a modular design: the wheel-leg module 2 and the tandem four-bar linkage leg structure 21 form the basis of motion. The rope drive module 4 (large and small rotating drums 41) replaces traditional gears / chains, reducing wear and noise. The control system utilizes a Raspberry Pi and a high-precision motor to achieve dynamic balance. The trunk integrated assembly 1 optimizes space and center of gravity. The wheel-foot components utilize 3D-printed hubs and anti-slip design to enhance mobility reliability. These components work together to achieve highly adaptable self-balancing motion in complex terrain.

[0122] The above description is merely a preferred embodiment of the present invention. However, the scope of protection of the present invention is not limited thereto. Any equivalent replacement or modification made by a person skilled in the art within the technical scope disclosed in the present invention and based on the technical solution and its improved conception shall be covered by the scope of protection of the present invention.

Claims

1. A bipedal wheel-legged self-balancing robot, characterized in that: include: The trunk integrated component integrates a control system for real-time acquisition of robot posture data and output of control instructions to achieve self-balancing adjustment of the robot and ensure the dynamic stability of the entire robot. Wheel-leg modules are located on both sides of the bottom of the robot. Each wheel-leg module contains a pair of serial four-link leg structures and a wheel hub drive assembly. The driving module is arranged in the torso integrated component and is connected to the wheel-leg module through a rope transmission module. It is used to drive the wheel-leg module to realize the flexion and extension of the legs. In conjunction with the wheel hub drive component, the robot has the dual capabilities of wheeled movement and leg-based obstacle crossing.

2. A bipedal wheel-legged self-balancing robot according to claim 1, characterized in that: The rope transmission module comprises: A small rotating drum coaxially connected to the output shaft end of the joint motor of the driving module; A large rotating drum is nested outside the power output shaft and is coaxially arranged with the power arm of the series four-link leg structure; The small rotating drum transmits the rotational power of the joint motor to the large rotating drum through a rope. The large rotating drum is used to receive the rope tension transmitted by the small rotating drum to drive the power arm to move.

3. The self-balancing robot with two wheels and legs according to claim 2, characterized in that: The surface of the small rotating drum is provided with a first thread groove and a guide hole, which are used for the stable winding of the rope and the adjustment of the rope entry angle respectively; The large rotating drum is provided with a second thread groove for winding the rope and forming a closed-loop transmission path.

4. The self-balancing robot with two wheels and legs according to claim 3, characterized in that: The second thread groove is a double-track thread groove, which is used for bidirectional rope winding and forming a closed-loop transmission path.

5. The self-balancing robot with two wheels and legs according to claim 2, characterized in that: A threaded hole is provided in the small rotating drum for screws to pass through, so as to improve the strength of the small rotating drum, transfer the force received to the four through screws, and fasten the drum to the output shaft end of the joint motor through four fastening screws on the end outward flange.

6. The self-balancing robot with two wheels and legs according to claim 2, characterized in that: The large rotating drum comprises: The inner large rotating drum serves as the power output shaft, and the power arm is sleeved and fixed on the inner large rotating drum; The outer large rotating drum is nested on the outside of the inner large rotating drum, forming a coaxial nested layout of "inner shaft-outer drum".

7. The self-balancing robot with two wheels and legs according to claim 6, characterized in that: The inner large rotating drum and the outer large rotating drum are connected to the tensioning device through an annular screw, which is used to adjust the tension of the rope and realize "soft limit" of the rope; The outer large rotating drum is provided with a limit groove for achieving "hard limit" on the rope.

8. The self-balancing robot with two wheels and legs according to claim 7, characterized in that: The free rotation angle of the inner large rotating drum and the outer large rotating drum is 0-150 degrees.

9. A bipedal wheel-legged self-balancing robot according to any one of claims 1 to 8, characterized in that: The wheel hub drive assembly comprises: On-wheel motors, a wheel hub, rotatably connected to the end of the series four-link leg structure and directly connected to the on-wheel motor; The tire is mounted on the outside of the wheel hub and directly contacts the ground.

10. The self-balancing robot with two wheels and legs according to claim 9, characterized in that: The outer surface of the wheel hub is covered with longitudinal lines, and the tire is a honeycomb solid tire.

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