Modularized distributed driving wheel set structure of electric drive chassis and control method and system of modularized distributed driving wheel set structure

Abstract

The invention belongs to the technical field of automobile driving wheel sets, and discloses an electrically-driven chassis modular distributed driving wheel set structure and a control method and system thereof in order to solve the problems that a traditional transmission shaft system is limited by mechanical transmission and is low in output power and transmission efficiency, the electrically-driven chassis modular distributed driving wheel set structure comprises an installation module, a movement module and a damping module, the mounting module is connected to one side of the wheel body through a mounting piece, the movement module is arranged on the mounting module and is configured to be a traveling driving unit used for driving the wheel body to travel and a steering driving unit used for driving the wheel body to steer, and the damping module is arranged on the mounting module. And the small shock absorbers are matched with the shock absorption bent belts to realize shock absorption on the wheel body in a working state. According to the distributed driving wheel set structure, the function of integrating driving, braking, steering and damping can be achieved, and the rationality and stability of the distributed driving wheel set structure design are verified through experiments.

Description

Technical Field

[0001] This invention relates to the field of automotive drive wheel assembly technology, and in particular to a modular distributed drive wheel assembly structure for an electric drive chassis and its control method and system. Background Technology

[0002] With the development of society and economy and the need for special tasks, the current demand for multi-axle special vehicle chassis is diverse. Moreover, the road driving environment of multi-axle special vehicles is diverse and complex. Chassis with special load-bearing and driving requirements is not universal, which increases vehicle design costs and development cycle and reduces production efficiency. It is often necessary to develop special chassis in a standardized and modular manner according to the application scenario and the current trend of electric drive development.

[0003] Traditional drive shaft systems are limited by mechanical transmission, resulting in long energy transfer paths, typically low output power and transmission efficiency. Furthermore, traditional drive shaft systems are complex and space-consuming. In contrast, the electric drive distributed drive wheel assembly chassis design has its own specific advantages. Firstly, the distributed drive system uses hub motors or wheel-side motors to drive the wheels, replacing the traditional drive shaft system. This reduces energy loss, increases output power, and significantly improves transmission efficiency, which is not limited by mechanical transmission. Secondly, the modular distributed design offers a high degree of integration; individual wheels can achieve rapid dynamic response through precise torque distribution control, reducing energy loss. Additionally, modular production offers high flexibility and adaptability, enabling rapid response to changes in market demand. Modular production allows for quick matching of task requirements, achieving customized production of multiple varieties, small batches, high quality, and low cost. Furthermore, modularity helps shorten the R&D cycle.

[0004] In view of this, an electric-driven distributed drive wheel set is designed to provide a high-efficiency, low-cost modular solution for multi-axle special vehicles. Furthermore, through an expandable control framework and system integration hardware, the collaborative control of the multi-wheel set structure can be realized. Summary of the Invention

[0005] To address the deficiencies in the existing technology, this invention aims to provide an electric drive chassis modular distributed drive wheel assembly structure and its control method and system, thereby solving the problems in the background section.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention discloses a modular distributed drive wheel assembly structure for an electric drive chassis, comprising: The mounting module is connected to one side of the wheel body via mounting hardware; The motion module, mounted on the mounting module, is configured as a travel drive unit for driving the wheels to move and a steering drive unit for driving the wheels to turn. The shock absorption module, installed on the mounting module, provides shock absorption for the wheels during operation.

[0007] As a further preferred embodiment of the above technical solution, the installation module includes: The wheel frame is connected to the clamping shaft of the wheel body; The upper support plate is located above the wheel frame, and the upper support plate is connected to the wheel frame through a shock-absorbing module.

[0008] A further preferred embodiment is that the wheel frame has a "mountain" shaped structure, and the middle part of the wheel frame has a first mounting hole and a second mounting hole from top to bottom. The first mounting hole is used to connect the driving unit, and the second mounting hole is used to install the mounting parts that are connected to the wheel body.

[0009] As a further preferred embodiment of the above technical solution, the mounting component includes: The rotating shaft passes through the second mounting hole; The bearing is fitted onto the rotating shaft and located within the second mounting hole; The mounting end cap is installed on the end of the wheel frame away from the wheel body, and the end of the rotating shaft is movably connected to the mounting end cap.

[0010] As a further preferred embodiment of the above technical solution, the travel drive unit includes: The drive motor is inserted through the first mounting hole and connected to the wheel frame; The first pinion is sleeved on the output shaft of the drive motor and located between the wheel frame and the wheel body; The large gear is fitted onto the rotating shaft and meshes with the first small gear.

[0011] As a further preferred embodiment of the above technical solution, the steering drive unit includes: The steering motor is mounted on the upper support plate. The second pinion is sleeved on the output shaft of the steering motor, and the second pinion is located at the top of the upper support plate; A fixed gear ring is located on the top of the upper support plate and is fixedly connected to the vehicle body, and the fixed gear ring meshes with the second pinion; The steering ring is located on top of the upper support plate and is movably mounted in the center of the fixed gear ring.

[0012] As a further preferred embodiment of the above technical solution, the vibration damping module includes: Shock absorbers are installed between the upper support plate and the wheel frame; The shock-absorbing curved strip is located on the side of the shock absorber away from the wheel body, and the shock-absorbing curved strip is an arc-shaped structure with both ends connected to the upper support plate and the wheel frame respectively.

[0013] A further preferred embodiment is that the shock absorber includes: The main body of the shock-absorbing head is connected to the upper support plate via a pin. End cap toothed ring, fitted onto the main body of the shock absorber head; The lower base center body is located at the bottom of the shock absorber head body and is connected to the wheel frame by a pin. The shock-absorbing spring is sleeved on the outside of the center body of the lower base, and the top of the shock-absorbing spring abuts against the toothed ring of the end cover.

[0014] Secondly, the present invention also discloses a control method for a modular distributed drive wheel assembly structure of an electric drive chassis, comprising the following steps: The host computer sends control commands to the controller; After receiving the control command, the controller transmits the control command to motor driver one and motor driver two through different ports of the CAN bus. Motor driver one is connected to the travel motor, and motor driver two is connected to the steering motor. The motor driver starts the travel motor to rotate, which in turn drives the first pinion to rotate. The first pinion then drives the large gear to rotate, and the large gear drives the rotating shaft to make the wheel set roll axially. At the same time, the second motor driver starts to rotate the steering motor, which in turn drives the second pinion to rotate. The second pinion meshes with the fixed gear ring and rotates around the fixed gear ring. At this time, the second pinion drives the upper support frame to rotate synchronously with the steering ring, causing it to deflect relative to the chassis connected to the fixed gear ring, thereby causing the wheel set to turn. During operation, the shock absorber and shock-absorbing belt work together to dampen the wheel set.

[0015] Thirdly, the present invention also discloses a control system for a modular distributed drive wheel assembly structure of an electric drive chassis, comprising: The host computer is equipped with the Ackerman steering algorithm, which generates steering angle and wheel speed signals for each wheelset structure based on the Ackerman steering algorithm and sends them to the controller through the host computer. The controller receives the steering angle and wheel speed signals of each wheel set structure sent by the host computer, compares them with the actual position and speed information of the drive motor and steering motor in the returned wheel set structure, generates control signal commands for the drive motor and steering motor based on the error between the two, and sends them to the motor driver via the CAN bus. The motor driver is used to receive control signal commands from the controller, complete the corresponding control of the drive motor and steering motor, and collect the speed information of the drive motor and the position information of the steering motor in real time, and return them to the controller via the CAN bus.

[0016] Fourthly, the present invention also discloses an electronic device, the electronic device comprising at least one processor and a memory communicatively connected to the processor; wherein the memory stores instructions executable by the processor, the instructions being executed by the processor to enable the processor to perform the steps of the method described above.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention constructs a motion module with a motor as its core. A first pinion gear, in conjunction with a large gear, drives the wheel. A second pinion gear, in conjunction with a fixed gear ring, rotates around the fixed gear ring, causing the second pinion gear, steering ring, and upper support frame to rotate together, thus enabling the wheel to steer. The upper support plate and wheel frame together form an integrated support system (i.e., the mounting module) for the wheel and chassis. A shock-absorbing module is installed between the upper support plate and the wheel frame. The shock-absorbing module uses a small shock absorber as the stabilizing center ring frame and shock-absorbing curved belts as auxiliary shock-absorbing components to counteract lateral tangential forces. Together, the mounting module, motion module, and shock-absorbing module constitute a distributed drive wheel assembly structure integrating driving, braking, steering, and shock absorption functions.

[0018] 2. The single wheel set of the present invention adopts an integrated control architecture, based on a dual operation mode with feedback correction. The drive motor and steering motor are equipped with encoders that can read the motor running speed and angle position parameters to achieve feedback correction and realize the integrated control of the electric drive chassis via an expandable CAN bus.

[0019] 3. This invention adopts a wheel set unit that integrates driving, braking, steering and shock absorption functions, eliminating the mechanical connection between wheel sets, which facilitates the expansion of the number of integrated wheel set units, and can quickly build vehicle chassis with different axle numbers, realize the expansion of vehicle axle numbers, and complete vehicle chassis reconstruction. Through integrated control and distributed drive architecture, driving control of different chassis configurations can be completed.

[0020] 4. This invention verifies the stability of the mechanical structure of the wheel set by conducting operational experiments on the distributed drive wheel set structure. The control error of the control system is no greater than 0.01, realizing the mechanical extensibility of the modular wheel set structure. After conducting experimental tests on the four-wheel set chassis prototype under various working conditions, the integrated control platform can achieve stable control with an error of no more than 0.01, verifying the rationality and stability of the distributed drive wheel set structure design. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below; the accompanying drawings described herein are used to provide a further understanding of the present invention, constitute a part of the present invention, and do not constitute an improper limitation of the present invention. In the accompanying drawings: Figure 1 This is a schematic diagram of the overall structure of a modular distributed drive wheel assembly structure for an electric drive chassis according to the present invention. Figure 2 This is another schematic diagram of the overall structure of the present invention; Figure 3 This is a partially enlarged view of the travel drive unit of the present invention; Figure 4 This is a longitudinal sectional view of the overall structure of the present invention; Figure 5 This is a structural diagram of the steering drive unit of the present invention; Figure 6 This is a top view of the overall structure of the present invention; Figure 7 This is a partially enlarged view of the steering drive unit of the present invention; Figure 8 This is a partial structural diagram of the shock absorption module of the present invention; Figure 9 This is a schematic diagram of the shock absorber of the present invention; Figure 10 This is a logic block diagram of the distributed drive wheel group control system of the present invention; Figure 11 The microcontroller used in this invention is the DM-MC-Board02. Figure 12 The present invention uses a USB to CAN converter instead of a CAN box; Figure 13 The power source used in this invention; Figure 14 This is a physical diagram of the distributed drive wheel assembly and the full wheel assembly experimental platform of the present invention; Figure 15 These are actual photos of the four-wheel chassis prototype used in the verification case of this invention. Figure 16 This is the experimental result of the four-wheel chassis prototype in the verification case of this invention under straight-line running conditions; Figure 17 The experimental results of the four-wheel chassis prototype in the verification case of this invention under the condition of self-rotation +45° are as follows; Figure 18 This is an experimental result of the four-wheel chassis prototype in the verification case of this invention under steering operation conditions; In the picture: 1. Mounting module; 11. Wheel frame; 12. Upper support plate; 13. Mounting component; 131. Rotating shaft; 132. Bearing; 133. Mounting end cover; 2. Motion module; 21. Travel drive unit; 211. Travel motor; 212. First pinion; 213. Large gear; 22. Steering drive unit; 221. Steering motor; 222. Second pinion; 223. Fixed gear ring; 224. Steering ring; 3. Vibration damping module; 31. Vibration damper; 311. Vibration damping head body; 312. End cap toothed ring; 313. Lower base center body; 314. Vibration damping spring; 32. Vibration damping bend; 4. Wheel body; 5. Pins. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can also refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Example 1

[0025] Reference Figures 1-9This invention provides a modular distributed drive wheel assembly structure for an electric drive chassis. The wheel assembly is designed as a three-in-one assembly of wheel body 4, hub, and clamping axle. The modular distributed drive wheel assembly structure of this invention includes an installation module 1, a motion module 2, and a shock absorption module 3. The installation module 1 is connected to one side of the wheel body 4 through an installation component 13. The motion module 2 is arranged on the installation module 1 and is configured as a travel drive unit 21 for driving the wheel body 4 to move and a steering drive unit 22 for driving the wheel body 4 to turn. The shock absorption module 3 is arranged on the installation module 1 to absorb shock from the wheel body 4 when it is in operation.

[0026] like Figure 1-2 , Figure 5 As shown, the mounting module 1 includes two parts: a wheel frame 11 and an upper support plate 12. The wheel frame 11 is connected to the wheel assembly's clamping shaft via a mounting component 13. The upper support plate 12 is positioned above the wheel frame 11, and the upper support plate 12 is connected to the wheel frame 11 via a shock-absorbing module 3. Specifically: The wheel frame 11 has a "mountain" shaped structure and is located on the side of the wheel set. The middle part of the wheel frame 11 has a first mounting hole and a second mounting hole from top to bottom. The first mounting hole is used to connect the driving unit 21, and the second mounting hole is used to install the mounting part 13 connected to the wheel body 4. The two ends of the wheel frame 11 in the horizontal direction are symmetrical L-shaped mounting brackets. The upper and lower ends of the L-shaped mounting brackets are provided with a first pin hole for connecting to the shock absorption module 3.

[0027] The upper support plate 12 is located at the top of the entire assembly, serving to support the steering drive unit 22, and is also responsible for transmitting the steering force of the steering drive unit 22 to drive the entire wheel set, causing the entire wheel set to rotate, and supporting the chassis in multi-wheel vehicle sets. Figure 1 As shown, the top of the upper support plate 12 is reserved with motor mounting holes and chassis mounting holes. The end of the upper support plate 12 connected to the shock absorption module 3 is provided with two sets of L-shaped connecting rods. Each set of L-shaped connecting rods contains two rods. The upper and lower ends of the L-shaped connecting rods are provided with second pin holes for connecting the shock absorption module 3.

[0028] In this embodiment, the mounting component 13 includes a rotating shaft 131, a bearing 132, and a mounting end cap 133, as shown in the figure. Figure 3-4 The rotating shaft 131 passes through the second mounting hole and has an A-shaped keyway. Two bearings 132 are provided, which are spaced apart on the rotating shaft 131 and are both located in the second mounting hole. The mounting end cover 133 is installed at the end of the wheel frame 11 away from the wheel body 4, and the end of the rotating shaft 131 is movably connected in the mounting end cover 133. The wheel frame 11 is connected to the wheel axle of the wheel set through the rotating shaft 131, bearings 132 and mounting end cover 133.

[0029] Motion module 2 is the power source for the distributed drive wheel assembly, such as... Figure 2 , Figure 4 As shown, the driving unit 21 includes a driving motor 211, a first pinion 212, and a large gear 213. The driving motor 211 passes through the first mounting hole and is connected to the wheel frame 11. A motor connecting plate is fixedly connected to the wheel frame 11, and the driving motor 211 is mounted on the motor connecting plate. The output shaft of the driving motor 211 extends through the first mounting hole to the side near the wheel assembly. The first pinion 212 is sleeved on the output shaft of the driving motor 211 and is located on the wheel frame. Between wheel 11 and wheel 4, a large gear 213 is sleeved on the rotating shaft 131, and the large gear 213 meshes with the first small gear 212; in this embodiment, the model of the propulsion motor 211 is DM-S3519-1EC, and the reduction ratio of the DM-S3519-1EC geared motor is 3591 / 187=1:19.2 (that is, the motor input shaft rotates 19.2 times, and the output shaft rotates 1 time), and it can work under a rated working voltage of 15V-52V, using 24V A 6000mAh safety lithium battery pack powers the motor 211, enabling it to operate at 24V. The rated torque of the DM-S3519-1EC is 3.5N·m, the peak torque is 7.8N·m, the rated speed is 395rpm, and the maximum speed under no-load is 435rpm. The first pinion 212 has a module of 2 and 13 teeth; the large gear 213 has a module of 2 and 65 teeth, and the transmission ratio between the first pinion 212 and the large gear 213 is 5.

[0030] like Figure 4-7 As shown, the steering drive unit 22 includes a steering motor 221, a second pinion 222, a fixed gear ring 223, and a steering ring 224. The steering motor 221 is mounted on the upper support plate 12. The second pinion 222 is fixedly sleeved on the output shaft of the steering motor 221 and is located at the top of the upper support plate 12. The fixed gear ring 223 is located at the top of the upper support plate 12 and is fixedly connected to the vehicle body, and the fixed gear ring 223 meshes with the second pinion 222. The steering ring 224 is fixedly connected to the top of the upper support plate 12, and the steering ring... The second pinion 224 is movably mounted at the center of the fixed gear ring 223. The second pinion 222 transmits the power of the steering motor 221 to achieve its own rotation. At the same time, the second pinion 222, together with the steering ring 224 and the upper support plate 12, rotates along the outer circumference of the fixed gear ring 223, causing the wheel set to steer relative to the chassis. In this embodiment, the steering motor 221 is also of the DM-S3519-1EC model. The second pinion 222 has the same model and size as the first pinion 212. The fixed gear ring 223 has a module of 2 and 70 teeth.

[0031] In this embodiment, the significance of setting both the travel motor 211 and the steering motor 221 as wheel-side motors instead of hub motors is that the travel motor 211 and the steering motor 221 are respectively suspended on the wheel frame 11 and the upper support frame. At the same time, in order to reduce the unsprung mass, the output shaft of the travel motor 211 is not directly connected to the wheel axle, which is beneficial to improve stability. In addition, the output shaft of the travel motor 211 does not have a keyway, avoiding the disadvantage of loosening after long-term operation.

[0032] like Figure 8-9 As shown, the shock absorption module 3 includes a shock absorber 31 and a shock absorption bend 32. The shock absorber 31 is arranged between the upper support plate 12 and the wheel frame 11, and the shock absorption bend 32 is arranged on the side of the shock absorber 31 away from the wheel body 4. The shock absorption bend 32 is an arc-shaped structure with both ends connected to the upper support plate 12 and the wheel frame 11 respectively. Specifically, the shock absorber 31 includes a shock absorber head body 311, an end cap gear ring 312, a lower base center body 313, and a shock absorber spring 314. The shock absorber head body 311 is connected to the upper support plate 12 via a pin 5. The end cap gear ring 312 is sleeved on the shock absorber head body 311. The lower end of the shock absorber head body 311 is a damper. The lower base center body 313 is connected to the bottom of the damper and is connected to the wheel frame 11 via a pin 5. The shock absorber spring 314 is sleeved on the outside of the lower base center body 313, and the top of the shock absorber spring 314 abuts against the end cap gear ring 312.

[0033] In this embodiment, both the damping head body 311 and the lower base center body 313 are made of nylon + glass fiber reinforced composite material, which combines lightweight and fatigue resistance. The end cap toothed ring 312 not only supports the damping spring 314, but also allows adjustment of the initial compression of the damping spring 314. The damping spring 314 wraps around the damper to form the core damping structure. The damping spring 314 is a high-strength alloy variable-diameter helical spring, guiding the axial deformation of the damping spring 314 and preventing energy loss or structural failure caused by lateral bending, thus forming a dynamic... The path constraint function is in a certain state. At the same time, the top coils of the damping spring 314 are relatively dense and the diameter is small, which enhances the initial support force when encountering violent fluctuations. When the initial support force is exceeded, as the central structure is compressed, the relatively loose spring coils at the bottom play a role in increasing the limit buffer. The damper 2 is internally designed as a mechanical friction damper. The bottom of the metal rod is supported by spring plates inside the damper. When the damping spring 314 is compressed downward, the damping head body 311 gives the metal rod a vibration frequency, and the spring plates at the lower end of the metal rod absorb the vibration energy to achieve the damping effect.

[0034] In this embodiment, a total of eight pins 5 are provided. Two pins 5 are used to connect the upper end of the shock-absorbing head body 311 to the upper support frame, two pins 5 are used to connect the lower end of the lower base center body 313 to the wheel frame 11, two pins 5 are used to connect the upper end of the shock-absorbing curved belt 32 to the upper support frame, and two pins 5 are used to connect the lower end of the shock-absorbing curved belt 32 to the wheel frame 11. The pins 5 cooperate with the pins and washers to achieve a flexible connection at the connection point.

[0035] During operation, with severe vibration, the upper support plate 12 inputs vibration impact force, and the damping belt 32 transmits the impact force through the pin 5, eliminating structural interference caused by multi-directional impact force. With the transmission of this flexible connecting medium, the high-frequency impact energy is preferentially dissipated through the tensile deformation of the damping belt 32, avoiding direct impact of high-frequency vibration on the damping spring 314 and causing metal fatigue. The remaining energy is transmitted to the damping spring 314 through the wheel frame 11, and the low-frequency energy is converted into elastic potential energy by compressing the stroke of the damping spring 314, thereby achieving a good vibration reduction effect.

[0036] The main parts in this embodiment are all made using a high-precision 3D printing process, with resin as the main material. The first pinion 212, the second pinion 222, the large gear 213, the fixed gear ring 223, and the steering ring 224 are made of aluminum alloy to ensure rigidity. Example 2

[0037] Reference Figure 10 This invention provides a control system for a modular distributed drive wheel assembly structure of an electric drive chassis, comprising: The host computer, also known as the host PC, is equipped with the Ackerman steering algorithm. Based on the steering angle and vehicle speed signal of wheel 4, the host computer generates the steering angle and wheel speed signal of each wheel set structure according to the Ackerman steering algorithm, and sends them to the controller. The controller, also known as the lower-level machine, is used to receive the steering angle and wheel speed signals of each wheel set structure sent by the upper-level machine, and compare them with the actual position and speed information of the drive motor and steering motor in the returned wheel set structure. Based on the error between the two, it generates control signal commands for the drive motor and steering motor, and sends them to the motor driver through the CAN bus. The motor driver is used to receive control signal commands from the controller, complete the corresponding control of the drive motor 211 and the steering motor 221, and collect the speed information of the drive motor and the position information of the steering motor in real time, and return them to the controller via the CAN bus.

[0038] In this embodiment, the host PC is programmed using PyCharm, which calls the DM_CAM.py and DM_Motor_Test.py example libraries, and places them in the same folder to construct the runtime environment.

[0039] like Figure 11 As shown, the controller in this embodiment uses a DM-MC-Board02 microcontroller with a FreeRTOS operating system. This microcontroller uses an STM32H723 chip and provides rich expansion interfaces, including one Octo-SPI (supporting HyperRAM / Flash expansion), two USB interfaces (including one 480Mbps high-speed OTG), two CAN FD buses, one Ethernet MAC (10 / 100Mbps), and one FMC interface (expandable to SRAM / LCD). It fully covers the control requirements of the drive wheel group, realizes high-speed communication to improve control accuracy and response speed, and provides interface services for complex peripheral device connection requirements. It provides highly integrated hardware support for multi-scenario applications and meets the communication requirements of multiple nodes. This embodiment uses a CAN bus to control the wheel assembly, such as... Figure 12 As shown, a USB-to-CAN converter is used instead of a CAN box to realize CAN node communication. The nodes are connected to the driver interface to form the vehicle's CAN bus. The USB-to-CAN cable consists of a USB-to-CAN module, a GH1.25 3-pin non-uniform cable, and a GH1.25 2-pin common-uniform cable. The host PC is connected to the motor driver via serial port COM3 through the USB-to-CAN cable. In this embodiment, the default serial port baud rate of 921600 is selected to ensure stable signal transmission.

[0040] like Figure 13 As shown, the wheel set is powered by a 24V 6000mAh safety lithium battery pack, weighing 1.72KG. It is equipped with a magnetic iron plate for easy fixing and installation. The battery can support simultaneous charging and discharging and has a built-in safety valve to effectively ensure reliable output and safe operation. During operation, it will simultaneously supply power to two motors. Both the drive motor 211 and the steering motor 221 are DM-S3519-1EC geared motors, which have three modes: MIT control mode, speed control mode, and position speed control mode. In this embodiment, the speed control mode is used for drive and the position speed control mode is used for steering.

[0041] In this embodiment, the host PC sends control commands to the wheel assembly, including parameters such as target speed and target rotation angle. It receives data through a virtual serial port driver and hands it over to the communication parsing task thread in FreeRTOS for processing. Based on the FreeRTOS operating system, two FreeRTOS threads are run for a single wheel assembly, including a command parsing thread (CommandTask) and a drive control thread (ControlTask). The command parsing thread is responsible for receiving and parsing the data frames sent by the computer through the USB-to-CAN virtual serial port. The drive control thread uses the target speed or target position information obtained from the command parsing to perform speed loop or position-speed dual loop control.

[0042] When the control system is running, the host computer (PC) inputs control signals to the slave computer. The slave computer parses the commands into electrical signals through a command parsing program, and transmits them to the motor driver via CAN, which converts them into corresponding current control signals. The control of the wheel set's movement and steering is achieved through gear transmission. Example 3

[0043] Based on the above control system, the present invention also provides a control method for a modular distributed drive wheel assembly structure of an electric drive chassis, comprising the following steps: Based on the wheelbase and track width parameters of the current configuration, the host computer calculates the turning angle of each wheel according to the Ackerman steering algorithm, distributes the torque, and then sends the control command to the controller. After receiving the control command, the controller processes it accordingly and then transmits the control command to motor driver 1 and motor driver 2 through different ports of the CAN bus. Motor driver 1 is connected to the travel motor 211, and motor driver 2 is connected to the steering motor 221. After receiving the control command, the motor driver drives the travel motor 211 to start rotating. The travel motor 211 drives the first pinion 212 to rotate, and the first pinion 212 synchronously drives the large gear 213 to rotate. The large gear 213 drives the rotating shaft 131 to make the wheel set roll axially. Simultaneously, the second motor driver also receives the control command and drives the steering motor 221 to start rotating. The steering motor 221 drives the second pinion 222 to rotate. The second pinion 222 meshes with the fixed gear ring 223 and rotates around the fixed gear ring 223. At this time, the second pinion 222 drives the upper support frame and the steering ring 224 to rotate synchronously, causing the chassis connected to the fixed gear ring 223 to deflect, thereby causing the wheel set to turn. During operation, the shock absorber 31 and the shock-absorbing curved belt 32 work together to dampen the wheel set.

[0044] Verification Case: like Figures 14-18 As shown, an operational experiment was conducted to verify the prototype vehicle integrating four distributed drive wheel sets: like Figure 15 As shown, the four-wheel prototype vehicle is equipped with four drive energy batteries, and the total weight of the vehicle is 43.77 kg. The total weight of the vehicle plus the host computer PC is 46.27 kg.

[0045] (1) Straight-line running condition test: The host computer integrated control system was set to send speed and rotation speed information at regular intervals. The speed of the four-wheel assembly was set to 0.5 rad / s and the angle to 0 degrees. A forward movement experiment was conducted, and the experimental data of the four-wheel assembly in straight-line operation were obtained as follows: Figure 16 The output waveforms of the four wheel sets are somewhat different. The blue and yellow waveforms of the left front wheel and right rear wheel fluctuate much more than the others, with wheel speed errors approaching 0.02m / s. This is because during the mechanical assembly process, improper wheel axle connection of the left front wheel and right rear wheel, whether too tight or too loose, can cause some free spin, resulting in a larger deviation in the wheel speed feedback received by the drive motor 211 and steering motor 221. However, overall, it meets the experimental expectations and verifies that the mechanical structure can operate reliably.

[0046] (2) Self-rotation operation test: The host computer integrated control system is set to send speed and rotation speed information at regular intervals. The speed of the four-wheel assembly is set to 0.5 rad / s. A self-rotation test is conducted when the assembly reaches a 45° angle, and the test data is obtained. Figure 17 During forward operation, the four-wheel prototype exhibited significant fluctuations in the deflection angles of the left rear wheel and right front wheel, with extreme values ​​exceeding 48°. This was attributed to a slight deviation in the overall center of gravity of the prototype. Since the height of each wheel assembly was determined by the shock-absorbing module 3 during the assembly of mechanical components, and the rotating pin of the shock-absorbing module 3 had an initial position error, this resulted in the overall center of gravity deviation. The overall driving trajectory remained relatively stable, and the drive motor operated smoothly without significant fluctuations. The overall performance met experimental expectations, validating the omnidirectional mechanical reliability of the wheel assembly.

[0047] (3) Steering operation condition test: When setting the steering mode, steering is achieved via the joystick on the user interface. During steering, the Ackermann steering algorithm model calculates the differential ratio. In the experiment, turning the joystick to the left caused the four-wheel prototype to turn right, and the steering operation was as follows: Figure 18 As shown, the speed range of the left wheel assembly is 0.59 m / s - 0.62 m / s, and the speed range of the right wheel assembly is 1.385 m / s - 1.415 m / s. With a wheelbase K = 1.2 m, the ratio of the left to right wheel speeds is 1:2, meaning the right wheel speed is twice the left wheel speed. The actual speeds conform to the speed-to-rotation ratio, and the experiment verifies that the differential speed distribution formula is followed during steering.

[0048] The steering angle curves of the four-wheel assembly show that the steering angle range for the left front wheel assembly is (62.8°, 63.9°), the right front wheel assembly is (40.1°, 41.3°), the left rear wheel assembly is (-62.6°, -63.9°), and the right rear wheel assembly is (-39.8°, -41.2°). The steering angles of the front wheels are slightly larger than those of the rear wheels. This is because the front wheels experience greater compressive force during steering, and the wheel damping mechanism influences the movement of the entire wheel assembly. The wheel assembly steering angles conform to the Ackermann steering angle, verifying that the four-wheel assembly prototype can complete steering under the control of the Ackermann model, which is in line with experimental expectations and also verifies the rationality of the wheel assembly structural design.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. An electric drive chassis modular distributed drive wheel set architecture, characterized by, The application relates to a wheel group, which comprises the following parts: an installation module connected to one side of a wheel body through an installation piece; a motion module arranged on the installation module and comprising a travel driving unit configured to drive the wheel body to travel and a steering driving unit configured to drive the wheel body to steer; a damping module arranged on the installation module and configured to damp the wheel body in a working state.

2. The electric drive chassis modular distributed drive wheel set structure according to claim 1, characterized in that, The installation module comprises: a wheel frame connected to the clamping shaft of the wheel body, wherein the wheel frame has a "mountain" shape structure, and a first installation hole and a second installation hole are sequentially arranged in the middle part of the wheel frame from top to bottom, wherein the first installation hole is used for connecting the travel driving unit, and the second installation hole is used for arranging the installation piece connected to the wheel body; an upper support plate arranged above the wheel frame and connected to the wheel frame through the damping module.

3. The electric drive chassis modular distributed drive wheel set structure according to claim 2, characterized in that, The installation piece comprises: a rotating shaft arranged in the second installation hole; a bearing arranged on the rotating shaft and located in the second installation hole; an installation end cover arranged at the end of the wheel frame away from the wheel body, and the end of the rotating shaft is movably connected to the installation end cover.

4. The electric drive chassis modular distributed drive wheel set structure according to claim 2, characterized in that, The travel driving unit comprises: a travel motor arranged in the first installation hole and connected to the wheel frame; a first pinion gear arranged on the output shaft of the travel motor and located between the wheel frame and the wheel body; a large gear arranged on the rotating shaft and engaged with the first pinion gear.

5. The electric drive chassis modular distributed drive wheel set structure according to claim 2, characterized in that, The steering driving unit comprises: a steering motor arranged on the upper support plate; a second pinion gear arranged on the output shaft of the steering motor and located at the top of the upper support plate; a fixed gear ring located at the top of the upper support plate and fixedly connected to the vehicle body, wherein the fixed gear ring is engaged with the second pinion gear; a steering ring located at the top of the upper support plate and movably arranged at the center of the fixed gear ring.

6. The electric drive chassis modular distributed drive wheel set structure according to claim 2, characterized in that, The damping module comprises: a damper arranged between the upper support plate and the wheel frame; a damping bent belt arranged at the side of the damper away from the wheel body, wherein the damping bent belt has an arc shape structure and is connected to the upper support plate and the wheel frame at two ends.

7. The electric drive chassis modular distributed drive wheel set structure according to claim 6, characterized in that, The damper comprises: a damping head main body connected to the upper support plate through a pin shaft; an end cover gear ring arranged on the damping head main body; a lower end base center body arranged at the bottom of the damping head main body and connected to the wheel frame through a pin shaft; a damping spring arranged outside the lower end base center body, and the top of the damping spring is in abutment with the end cover gear ring.

8. The control method of the electric drive chassis modular distributed drive wheel group structure according to any one of claims 1-7, characterized in that, The application further relates to a control method of the wheel group, which comprises the following steps: sending a control instruction from an upper computer to a controller; after the controller receives the control instruction, transmitting the control instruction to a motor driver I and a motor driver II through different ports of a CAN bus, wherein the motor driver I is connected to the travel motor, and the motor driver II is connected to the steering motor; the motor driver I drives the travel motor to start rotating, the travel motor drives the first pinion gear to rotate, the first pinion gear synchronously drives the large gear to rotate, and the large gear drives the rotating shaft to make the wheel group axially roll; at the same time, the motor driver II drives the steering motor to start rotating, the steering motor drives the second pinion gear to rotate, the second pinion gear is engaged with the fixed gear ring and rotates around the fixed gear ring, at this moment, the second pinion gear drives the upper support frame and the steering ring to synchronously rotate, and the vehicle chassis connected to the fixed gear ring is deflected, so that the wheel group is deflected to move; and in the running process, the wheel group is damped through the cooperation of the damper and the damping bent belt.

9. A control system for an electric drive chassis modular distributed drive wheel set architecture, characterized by, The control system is used to realize the control method in claim 8, comprising: A host computer, which is loaded with Ackerman steering algorithm, generates steering angle and wheel speed signal of each wheel group structure based on Ackerman steering algorithm, and sends the steering angle and wheel speed signal to the controller through the host computer; The controller is used to receive the steering angle and wheel speed signal of each wheel group structure sent by the host computer, compare the actual position and speed information of the traveling motor and the steering motor in the returned wheel group structure, generate control signal instruction of the traveling motor and the steering motor according to the error of the two, and send the control signal instruction to the motor driver through the CAN bus; The motor driver is used to receive the control signal instruction from the controller, complete corresponding control of the traveling motor and the steering motor, and collect the speed information of the traveling motor and the position information of the steering motor in real time, and return the speed information and the position information to the controller through the CAN bus.

10. An electronic device, comprising: The electronic device includes at least one processor, and a memory connected with the processor in communication; wherein the memory stores instructions executable by the processor, and the instructions are executed by the processor to enable the processor to perform the steps of the method in claim 8.

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