Modular wheel-legged robot structure driven by full-bus steering engine

Abstract

A kind of full bus steering engine driven modular wheel-foot robot structure belongs to wheel-foot mobile robot technical field, including body assembly, control module assembly, four identical leg assemblies and wheel-foot drive module;In leg assembly, the output shaft of first serial bus steering engine is fixedly connected with the first end of first thigh link;The output shaft of second serial bus steering engine is fixedly connected with the first end of second thigh link;The end of first thigh link is hingedly connected with the first end of first shank link, and the end of second thigh link is hingedly connected with the first end of second shank link;In wheel-foot drive module, the output shaft of third serial bus steering engine is drivingly connected with one side of wheel shaft through steering wheel, and third serial bus steering engine is installed at the end of first shank link;The other side of wheel shaft is connected with the end of second shank link through angular contact bearing.The modular degree of the application is high, maintenance is convenient and the ability of adapting complex terrain is strong.

Description

Technical Field

[0001] This invention belongs to the field of wheeled mobile robot technology, and in particular to a modular wheeled robot structure driven by a fully bus servo motor. Background Technology

[0002] To combine the advantages of wheeled and legged robots, hybrid wheel-legged robots have gradually become a research hotspot in the industry. However, existing solutions still have significant drawbacks: some solutions adopt a wheel-leg separated architecture, setting up independent wheeled drive units and legged drive units, which results in structural redundancy, large overall weight, low mode switching efficiency, long transmission chains, and poor reliability. Another mainstream solution adopts a wheel-leg integrated architecture, integrating the drive wheels into the leg end. Although this solves the problem of structural redundancy, it generally suffers from insufficient bus integration and imperfect modular design. Existing servos cannot achieve real-time bidirectional feedback of multiple parameters such as position, speed, torque, and temperature, making it difficult to achieve adaptive closed-loop control based on working conditions. At the same time, the leg structure cannot be quickly disassembled and interchanged, resulting in high maintenance costs and failing to meet the actual usage requirements of high adaptability, high reliability, and easy maintenance in complex industrial scenarios. Summary of the Invention

[0003] To overcome the shortcomings of existing wheeled robot servo drive methods, such as unreasonable wiring, redundant wiring and low integration due to the use of ordinary PWM servos, lack of multi-parameter feedback capability, insufficient torque, low mode switching efficiency, and poor adaptability to complex terrain, this invention provides a modular wheeled robot structure driven by a serial bus servo drive, which features extremely simple wiring, high integration, real-time feedback of multiple parameters such as position, voltage, and temperature, sufficient torque, efficient mode switching, and strong adaptability to complex terrain.

[0004] The technical solution of this invention is as follows: A modular wheeled robot structure driven by a fully bus servo motor includes a body assembly, a control module assembly, a power module, four identical leg assemblies, and a wheel drive module installed at the end of each leg assembly. The leg assembly includes a first serial bus servo, a second serial bus servo, a first thigh link, a second thigh link, a first lower leg link, and a second lower leg link. The first and second serial bus servos are mounted on the fuselage assembly. The output shaft of the first serial bus servo is fixedly connected to the head end of the first thigh link; the output shaft of the second serial bus servo is fixedly connected to the head end of the second thigh link; the end of the first thigh link is hinged to the head end of the first lower leg link, and the end of the second thigh link is hinged to the head end of the second lower leg link. The wheel drive module includes a third serial bus servo, a wheel axle, and a walking wheel fixed on the wheel axle. The output shaft of the third serial bus servo is connected to one side of the wheel axle via a servo disc. The third serial bus servo is mounted at the end of the first lower leg link. The other side of the wheel axle is connected to the end of the second lower leg link via an angular contact bearing. The control terminals of the first serial bus servo, the second serial bus servo, and the third serial bus servo are communicatively connected to the control module assembly.

[0005] Furthermore, the first, second, and third serial bus servos are connected in series via a single bus cable. This bus cable includes a power supply line and a data communication line. After exiting the main control bay, the cable is concealed through internal channels of the thigh and lower leg linkages, ultimately connecting to the third serial bus servo. This is the preferred embodiment. Alternatively, the bus cable can be installed without concealment, directly connecting to the third serial bus servo after exiting the main control bay.

[0006] Preferably, the control module assembly includes an Intel N97 mini-host as the host computer and an STM32F446RCT6 microcontroller as the slave computer; the slave computer communicates with the first serial bus servo, the second serial bus servo, and the third serial bus servo via a serial port, outputs bus protocol frames to control each serial bus servo, and receives real-time feedback data of multiple parameters from each serial bus servo.

[0007] Furthermore, the modular wheeled robot structure also includes a power module, which uses a 24V power lithium battery as the total input and constructs three independent voltage-regulated power supply domains through a multi-channel step-down module: a 3.3V main control and IMU sensor weak current domain, a 12V servo motor power domain, and a 12V host computer domain.

[0008] Furthermore, the fuselage assembly adopts a layered quick-release modular structure, with a detachable control module assembly, power module, and leg assembly installed sequentially from top to bottom, and each layer is fixed by quick-release bolts.

[0009] Preferably, in the leg assembly, the center distance between the output shafts of the first serial bus servo and the second serial bus servo is 60mm, the center distance between the joints of the first thigh link and the second thigh link is 90mm, the center distance between the joints of the first lower leg link and the second lower leg link is 150mm, and the diameter of the walking wheel is 85mm.

[0010] In the wheel drive module, the third serial bus servo is installed in the mounting slot at the end of the first leg. The output shaft of the third serial bus servo is connected to the wheel axle through a 25T servo disk. The spline structure of the wheel axle is coaxially driven with one side of the traveling wheel. The other side of the traveling wheel is in contact with the bearing inner ring limiting shaft. The angular contact bearing is installed in the groove at the end of the second leg connecting rod. The bearing inner ring limiting shaft cooperates with the inner ring of the angular contact bearing to achieve coaxial rotation. The shaft end retaining ring abuts against the outer ring of the angular contact bearing and is fixed in the groove at the end of the second leg connecting rod.

[0011] The modular wheeled robot also includes a bidirectional communication protocol system between the upper and lower computers that works in conjunction with the control module assembly. This communication protocol system adopts a frame format with a fixed frame header and a variable-length data field. The frame starts with a 2-byte fixed frame header of 0xFF 0xFF and uses an accumulation and verification mechanism with frame header conflict correction.

[0012] The present invention adopts the above-mentioned modular wheeled robot structure scheme driven by a full bus servo motor, which has the following advantages compared with the existing wheeled robot structure: 1. Fully modular structural design, convenient disassembly and maintenance, and extremely strong versatility and expandability.

[0013] 2. The all-bus driven architecture simplifies wiring and significantly improves the overall integration and reliability of the device.

[0014] 3. It can transmit back the position, speed, temperature, voltage and fault codes collected by the built-in sensors of the servo motor, providing an endogenous data foundation for full closed-loop control and reducing reliance on external sensors.

[0015] 4. No redundant switching mechanism, balancing traffic efficiency and obstacle-crossing capability.

[0016] 5. It is equipped with a communication protocol for upper and lower computers that is compatible with the full bus architecture, supports 100Hz closed-loop control, and has the ability to control the whole machine and single wheels. It also has multiple reliability protection mechanisms, which greatly improves the system's safety and fault tolerance. Attached Figure Description

[0017] Figure 1 This is an isometric view of a modular wheeled robot structure driven by a fully bus-driven servo motor.

[0018] Figure 2 It is an isometric view of the control module assembly.

[0019] Figure 3 This is an isometric view of the leg assembly.

[0020] Figure 4 This is a diagram of a wheel-driven structure.

[0021] Figure 5 This is a structural schematic diagram of the fuselage assembly.

[0022] Figure 6 This is a diagram showing the dimensions of the leg linkage.

[0023] Figure 7 This is a PCB circuit design flowchart.

[0024] The attached diagram is labeled as follows: 1 is the fuselage assembly, 1-1 is a 15cm aluminum profile, 1-2 is an angle bracket, 1-3 is a 42cm aluminum profile, 1-4 is a 30cm aluminum profile, and 1-5 is a straight bracket; 2-1 is the first serial bus servo, 2-2 is the second serial bus servo, and 2-3 is the third serial bus servo; 3 is the wheel drive module, 3-1 is the wheel axle, 3-2 is the 25t transmission servo disc, 3-3 is the M3x65 fixing stud, 3-4 is the bearing inner ring limiting shaft, 3-5 is the 7000AC angular contact bearing, 3-6 is the shaft end retaining ring, and 3-7 is the running wheel; 4 is the leg assembly; 4-1 is the servo mounting bracket; 4-2 is the bearing mounting bracket; 4-3 is the 7004AC angular contact bearing; 4-4 is the hexagon socket rivet; 4-5 is the first thigh connecting rod; 4-6 is the first lower leg connecting rod; 4-7 is the second lower leg connecting rod; 4-8 is the hexagon socket rivet; 4-9 is the joint drive shaft; 4-10 is the 18t transmission servo disc; 4-11 is the perforated plate; 4-12 is the second thigh connecting rod. 5 is the power supply module; 6 is the control module assembly; 6-1 is an 11mm hexagonal support copper pillar; 6-2 is the power supply module PCB board; 6-3 is the main control module PCB board; 6-4 is the bottom mounting bracket; 6-5 is the cooling fan mounting bracket; 6-6 is the cooling fan; 6-7 is the host mounting bracket; 6-8 is a 45mm hexagonal support copper pillar; 6-9 is a 17mm hexagonal support copper pillar; 6-10 is a 5mm hexagonal support copper pillar; 6-11 is the Intel N97 mini host. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings.

[0026] Reference Figures 1-7 A modular wheeled robot structure driven entirely by a bus servo motor includes a body assembly 1, a wheel and leg drive module 3, a leg assembly 4, a power module 5, and a control module assembly 6. The first serial bus servo motor 2-1 and the second serial bus servo motor 2-2 are HTD-85H intelligent bus servo motors manufactured by Huaner Technology, with a stall torque of 85 kg·cm. They operate in servo mode and geared motor mode, and can provide feedback on position, temperature, voltage, and fault code parameters. The first serial bus servo motor 2-1 and the second serial bus servo motor 2-2 serve as the drive source for the legs. The drive source for the walking wheels is a third serial bus servo motor 2-3, which is a MicroSnow ST3215 bus servo motor with a stall torque of 30 kg·cm. It operates in servo mode and geared motor mode, and can provide feedback on voltage, position, and speed parameters.

[0027] The fuselage assembly 1 includes a 15cm aluminum profile 1-1, corner brackets 1-2, a 42cm aluminum profile 1-3, a 30cm aluminum profile 1-4, and straight brackets 1-5. Two 15cm aluminum profiles 1-1 and two 42cm aluminum profiles 1-3 are secured together using eight corner brackets 1-2 with boat nuts and studs. Two 30cm aluminum profiles 1-4 are secured together with the 42cm aluminum profiles 1-3 using eight straight brackets with boat nuts and studs.

[0028] The wheel drive module 3 includes a third serial bus servo motor 2-3, a 25t transmission servo disc 3-2, a wheel axle 3-1, a traveling wheel 3-7, a 7000AC angular contact bearing 3-5, a bearing inner ring limiting shaft 3-4, a shaft end retaining ring 3-6, and an M3x65 fixing stud 3-3. Its power transmission and shaft system assembly structure is as follows: the third serial bus servo motor 2-3 is installed at the end of the first small leg connecting rod 4-6, and its output gear shaft is connected to the 25t... The transmission rudder 3-2 engages with the drive mechanism; the 25t transmission rudder 3-2 is coaxially fixed to the wheel axle 3-1 via four fixing studs, achieving synchronous torque transmission; one side of the traveling wheel 3-7 is coaxially fixed to the wheel axle 3-1 via a spline structure at the end of the wheel axle 3-1, rotating synchronously with it; the other side of the traveling wheel 3-7 contacts the bearing inner ring limiting shaft 3-4, and the 7000AC angular contact bearing 3-5 is installed in the groove at the end of the second small leg connecting rod 4-7, with the bearing inner ring limiting shaft 3-4 and the 7000AC angular contact shaft... The inner ring of bearing 3-5 is engaged to achieve coaxial rotation; the shaft end retaining ring 3-6 abuts against the outer ring of the 7000AC angular contact bearing 3-5, and the shaft end retaining ring is fixed in the groove at the end of the second small leg connecting rod; finally, an M3x65 fixing stud 3-3 is inserted from the center hole at the end of the second small leg connecting rod 4-7, passes through the center hole of the wheel axle 3-1 and the bearing inner ring limiting shaft 3-4, and passes through the entire transmission shaft system. The end is locked into the center hole of the output gear shaft of the third serial bus servo 2-3 by thread, thus completing the axial locking of the entire transmission shaft system.

[0029] The leg assembly structure 4 includes a first serial bus servo 2-1, a second serial bus servo 2-2, a servo mounting bracket 4-1, a bearing mounting bracket 4-2, a 7004AC angular contact bearing 4-3, an internal hexagonal rivet 4-4, a first thigh connecting rod 4-5, a first lower leg connecting rod 4-6, a second lower leg connecting rod 4-7, an internal hexagonal rivet 4-8, a joint drive shaft 4-9, an 18t drive servo disc 4-10, a perforated plate 4-11, and a second thigh connecting rod 4-12. The first serial bus servo 2-1 is mounted on the servo mounting bracket 4-1, and the servo mounting bracket 4-1 is connected to the perforated plate 4-11 by studs. Its output shaft gear meshes with the 18t transmission servo disc 4-10 for transmission; the 18t transmission servo disc 4-10 is coaxially fixed to the joint transmission shaft 4-9 through 8 M2.5 fixing studs; the first thigh connecting rod 4-5 is bolted to the corresponding holes of the joint transmission shaft 4-9 through 4 mounting holes evenly distributed around its circumference; finally, the fixing stud is screwed into the center hole of the first thigh connecting rod 4-5 and locked and fixed to the center hole of the output shaft of the first serial bus servo 2-1; the joint transmission shaft 4-9 passes through the inner ring of the 7004AC angular contact bearing 4-3, the 7004AC angular contact bearing 4-3 is installed in the bearing mounting bracket 4-2, and the bearing mounting bracket 4-2 is installed on the perforated plate 4-11, which can effectively offset the axial load of the transmission shaft system, avoid the output bearing of the first serial bus servo 2-1 from being subjected to additional axial force, and improve the service life and transmission stability of the servo; the other joint of the wheel leg drive device adopts the same transmission and assembly structure. The first thigh link 4-5 and the first lower leg link 4-6, and the second thigh link 4-12 and the second lower leg link 4-7 adopt a hinged assembly structure: two sets of 7000AC angular contact bearings 3-5 are respectively installed at the hinged ends of the first thigh link 4-5 and the second thigh link 4-12. Hexagonal rivets 4-4 pass through the inner rings of the corresponding 7000AC angular contact bearings 3-5, and are locked to the first lower leg link 4-6 and the second lower leg link 4-7 respectively with hexagonal rivets 4-8. The hexagonal rivets 4-4 act as pivots, allowing for free and unimpeded rotation between the first thigh link 4-5 and the first lower leg link 4-6, and between the second thigh link 4-12 and the second lower leg link 4-7. (Refer to...) Figure 6 The wheel-leg drive device employs kinematically and dynamically optimized dual-link dimensions. The center distance between the output shafts of the dual serial bus servo motors in the legs is 60mm, the center distance between the thigh link joints is 90mm, the center distance between the lower leg link joints is 150mm, and the diameter of the end-walking wheel is 85mm, forming a 1:1.67 thigh-to-leg length ratio. This dimensional combination ensures no mechanical interference in the legs within a ±90° full range of motion, keeps the overall center of gravity height below 180mm, and achieves a maximum static obstacle-crossing height of 75mm, balancing leg-based obstacle-crossing capability, wheeled driving stability, and structural reliability.

[0030] The power module 5 includes a battery mounting base, a 24V power lithium battery pack, and a battery protective cover. The power module 5 has two sets of 24V power lithium battery packs, which are symmetrically installed on the left and right sides of the middle of the body assembly 1 through the battery mounting base. The battery protective cover is fastened to the outside of the battery mounting base for sealing and fixation. The two sets of 24V power lithium battery packs provide the total power input for the whole machine. Three independent voltage-regulated power supply domains are constructed through a multi-channel step-down module: a 3.3V main control and IMU sensor weak current domain, a 12V servo motor power domain, and a 12V host computer domain. This provides a stable power supply for the robot's bus servo drive system, main control system, and host computer system. The symmetrical layout can optimize the robot's center of gravity distribution and improve the stability of the body during movement.

[0031] The control module assembly 6 includes an Intel N97 mini host 6-11, a cooling fan mounting bracket 6-5, a cooling fan 6-6, a power module PCB board 6-2, a main control module PCB board 6-3, a bottom mounting bracket 6-4, a host mounting bracket 6-7, and multiple sets of hexagonal support copper pillars. Its modular assembly structure is as follows: the power module PCB board 6-2 and the main control module PCB board 6-3 are arranged in parallel layers. They are coaxially locked to the bottom mounting bracket 6-4 by screwing in 11mm hexagonal support copper pillars 6-1, 17mm hexagonal support copper pillars 6-9, and 5mm hexagonal support copper pillars 6-10, forming the lower electrical mounting cavity. The cooling fan 6-6 is embedded in the matching mounting slot of the cooling fan mounting bracket 6-5. The Intel N97 mini PC 6-11 is locked to the top surface of the host mounting bracket 6-7 by screwing in studs. The host mounting bracket 6-7 and the cooling fan mounting bracket 6-5 are fixedly connected to the bottom mounting bracket 6-4 by screwing in 45mm hexagonal support copper pillars 6-8, forming the upper host mounting cavity, thus completing the layered modular integration assembly of the entire main control module. Finally, it is installed onto the perforated board 4-11 through the holes on the bottom mounting bracket 6-4. In this module, the power module PCB board 6-2 provides power management and distribution for the whole machine, the main control module PCB board 6-3 provides core motion control for the robot, the Intel N97 mini host 6-11 provides computing power support for upper computer computing and remote interaction, and the cooling fan 6-6 provides forced air cooling for the core computing unit to ensure stable operation of the system under complex working conditions.

[0032] In this embodiment, to achieve remote control, parameter configuration, and full-state monitoring of the fully bus-driven modular wheeled robot, a bidirectional communication protocol system adapted to the full bus-driven architecture is designed. This communication protocol system is based on a UART / USB to serial / network transparent transmission link, enabling full-duplex communication between the PC host computer and the robot's main control module. The basic communication baud rate is fixed at 1000000bps (1Mbps), perfectly matching the communication baud rate of the robot's back-end serial bus servo motor. It can stably support the robot's 100Hz closed-loop control cycle, fully adapting to the core requirements of independent single-leg control and integrated wheel-leg movement in the modular wheeled structure.

[0033] Table 1 shows the frame structure format of the communication protocol between the host computer and the slave computer.

[0034] The communication protocol system adopts a unified frame format with a fixed frame header and a variable-length data field, which has strong anti-interference capabilities and high frame recognition accuracy. The frame structure is defined as follows: the frame starts with a 2-byte fixed frame header 0xFF 0xFF, the third byte is a checksum field, the fourth byte is a frame length field, the value of which is the number of bytes in the data field plus 4, and the fifth byte to the end of the frame is a variable-length data field, which contains core content such as instruction code, wheel and foot number, motion parameters, and status data.

[0035] The communication protocol system employs an accumulated checksum mechanism with frame header conflict correction. This ensures data transmission accuracy while completely avoiding erroneous frame identification caused by checksum overlap with the frame header. The specific rules are as follows: The checksum calculation covers all intra-frame bytes except the checksum field itself and the frame header, i.e., all bytes in the frame length field and all data fields. The hexadecimal values ​​of all these bytes are accumulated to obtain the calculated checksum. If the calculated checksum is exactly 0xFF (consistent with the frame header value), the sending end forcibly fills in 0xAA in the checksum field. After receiving a data frame, the receiving end recalculates the checksum according to the same rules. A frame is considered valid if either of the following conditions is met: ① The calculated result is completely consistent with the intra-frame checksum; ② The calculated result is 0xFF, and the intra-frame checksum is 0xAA. Frames that do not meet the conditions are discarded, triggering a timeout retransmission mechanism.

[0036] The instruction set of the communication protocol system in this example is fully compatible with the modular structure and full-bus drive architecture of this robot. It is divided into five main categories according to function, enabling flexible independent control of individual wheels and feet as well as unified control of the entire robot. The categories are: System Management: Responsible for basic system management and communication maintenance, including communication testing, control board reset, and emergency stop commands; Overall Motion Control: Adapts to the integrated wheel and foot motion requirements, including commands for body balance start / stop, stop, movement, rotation, compound motion, and overall robot status reporting; Wheel and Foot Module Control: Corresponds to the modular wheel and foot structure, supporting independent control of individual legs, including commands for servo enable, wheel and foot position read / write, single wheel and foot start / stop, and speed setting; Parameter Configuration: Enables online configuration of servo and control system parameters, including commands for PID parameters, protection thresholds, operating condition parameter configuration, and parameter saving; Status Reporting: Responsible for real-time reporting of all status data, including commands for single servo status, overall robot status, IMU data, fault alarms, and heartbeat packets.

[0037] The standard communication workflow of the communication protocol system is fully compatible with the modular structure of this robot, and consists of three core components: Initialization handshake process: After the system is powered on and completes hardware initialization, the main control module sends the initial state of the whole machine and the initial position data of each modular wheel foot to the host computer through the communication protocol. After receiving the data, the host computer replies with a communication test command to complete the two-way communication handshake. Real-time closed-loop control process: During normal operation, the host computer issues whole-machine motion or single-wheel foot control commands according to control requirements. After parsing the commands, the main control module completes gait calculation and full-bus servo drive. At the same time, it reports the whole-machine full-state data to the host computer at a 100Hz cycle, completing one closed-loop control cycle. Anomaly handling process: The main control module sends a heartbeat packet to the host computer every 1 second. If no heartbeat packet is received within 3 seconds, it is determined that the communication link is interrupted, and the emergency shutdown process is immediately triggered to shut down the torque output of all servos. If the single frame data verification fails, a timeout retransmission is immediately triggered. If the retransmission fails 3 times in a row, an alarm is reported and graded safety protection is implemented.

[0038] The modular wheeled robot circuit system driven by a fully bus servo motor disclosed in this embodiment provides hardware support for the modular structure and fully closed-loop control system of the robot. The specific implementation of this circuit system will be described in detail below with reference to the accompanying drawings.

[0039] The circuit system in this embodiment provides hardware support for modular structure and fully closed-loop control. The system uses STM32F446RCT6 as the lower-level main control core and a 24V power lithium battery as the total input power.

[0040] The power supply adopts a three-domain independent voltage regulation architecture: the main control and sensor weak current domain, the servo motor power domain, and the host computer domain are each powered by an independent step-down branch. The power supply circuits of each domain share a common ground on the input side and are filtered separately on the output side to suppress the conducted interference of servo motor start-stop and host computer load fluctuations on the main control and IMU. Each mechanical leg's servo motor power branch has an independent enable control terminal, which can be used by the main control to shut down the faulty branch without affecting the operation of the other branches.

[0041] The entire machine has 12 bus servos connected in series via a serial bus to form a distributed bus network. The main controller achieves automatic half-duplex transmission and reception switching through a tri-state buffer, communicates bidirectionally with each servo, issues position, speed, and torque commands, and receives position, speed, temperature, voltage, and fault codes returned by the servos, providing intrinsic status data for full closed-loop control.

[0042] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Various equivalent substitutions or modifications made by those skilled in the art without departing from the spirit and substance of the present invention should be included within the scope of protection of the present invention.

Claims

1. A modular wheeled robot structure driven entirely by bus servo motors, characterized in that, It includes the fuselage assembly, the control module assembly, four identical leg assemblies, and a wheel drive module installed at the end of each leg assembly; The leg assembly includes a first serial bus servo, a second serial bus servo, a first thigh link, a second thigh link, a first lower leg link, and a second lower leg link. The first and second serial bus servos are mounted on the fuselage assembly. The output shaft of the first serial bus servo is fixedly connected to the head end of the first thigh link; the output shaft of the second serial bus servo is fixedly connected to the head end of the second thigh link; the end of the first thigh link is hinged to the head end of the first lower leg link, and the end of the second thigh link is hinged to the head end of the second lower leg link. The wheel drive module includes a third serial bus servo, a wheel axle, and a walking wheel fixed on the wheel axle. The output shaft of the third serial bus servo is connected to one side of the wheel axle via a servo disc. The third serial bus servo is mounted at the end of the first lower leg link. The other side of the wheel axle is connected to the end of the second lower leg link via an angular contact bearing. The control terminals of the first serial bus servo, the second serial bus servo, and the third serial bus servo are communicatively connected to the control module assembly.

2. The modular wheeled robot structure driven by a fully bus servo motor as described in claim 1, characterized in that, The first serial bus servo, the second serial bus servo, and the third serial bus servo are connected in series via a bus cable. The bus cable includes a pair of power supply lines and a data communication line. After being led out from the main control compartment of the fuselage, the bus cable is concealed through the internal channels of the thigh linkage and the lower leg linkage, and finally connects to the third serial bus servo.

3. The modular wheeled robot structure driven by a fully bus servo motor as described in claim 1 or 2, characterized in that, The control module assembly includes an Intel N97 mini-host as the host computer and an STM32F446RCT6 microcontroller as the slave computer. The slave computer communicates with the first serial bus servo, the second serial bus servo, and the third serial bus servo via a serial port, outputs bus protocol frames to control each serial bus servo, and receives real-time feedback data of multiple parameters from each serial bus servo.

4. The modular wheeled robot structure driven by a fully bus servo motor as described in claim 1 or 2, characterized in that: The modular wheeled robot structure also includes a power module, which uses a 24V power lithium battery as the total input and constructs three independent voltage-regulated power supply domains through a multi-channel step-down module: a 3.3V main control and IMU sensor weak current domain, a 12V servo motor power domain, and a 12V host computer domain.

5. The modular wheeled robot structure driven by a fully bus servo motor as described in claim 4, characterized in that, The fuselage assembly adopts a layered quick-release modular structure, with a detachable control module assembly, power module, and leg assembly installed sequentially from top to bottom, and each layer is fixed by quick-release bolts.

6. The modular wheeled robot structure driven by a fully bus servo motor as described in claim 1 or 2, characterized in that, In the leg assembly, the center distance between the output shafts of the first serial bus servo and the second serial bus servo is 60mm, the center distance between the joints of the first thigh link and the second thigh link is 90mm, the center distance between the joints of the first lower leg link and the second lower leg link is 150mm, and the diameter of the walking wheel is 85mm.

7. The modular wheeled robot structure driven by a fully bus servo motor as described in claim 1 or 2, characterized in that, In the wheel drive module, the third serial bus servo is installed in the mounting slot at the end of the first leg. The output shaft of the third serial bus servo is connected to one side of the wheel axle through a 25T servo disk. The spline structure of the wheel axle is coaxially driven with one side of the walking wheel.

8. The modular wheeled robot structure driven by a fully bus servo motor as described in claim 7, characterized in that, The other side of the traveling wheel is in contact with the inner ring limiting shaft of the bearing. The angular contact bearing is installed in the groove at the end of the second lower leg connecting rod. The inner ring limiting shaft of the bearing and the inner ring of the angular contact bearing cooperate to achieve coaxial rotation. The shaft end retaining ring abuts against the outer ring of the angular contact bearing and is fixed in the groove at the end of the second lower leg connecting rod.

9. The modular wheeled robot structure driven by a fully bus servo motor as described in claim 1 or 2, characterized in that, The modular wheeled robot also includes a bidirectional communication protocol system between the upper and lower computers that works in conjunction with the control module assembly. This communication protocol system adopts a frame format with a fixed frame header and a variable-length data field. The frame starts with a 2-byte fixed frame header of 0xFF 0xFF and uses an accumulation and verification mechanism with frame header conflict correction.

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