New energy electric vehicle experiment teaching device
By combining modular transparent chassis and digital twin technology, the problems of high cost, lack of visibility, safety hazards and experimental limitations of new energy vehicle teaching equipment have been solved, achieving safe, intuitive, interactive and economical teaching results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHONGQING UNIV
- Filing Date
- 2026-01-29
- Publication Date
- 2026-05-08
AI Technical Summary
Existing teaching equipment for new energy vehicles is expensive, has an invisible structure, poses high-voltage safety hazards, lacks experimental flexibility, and is disconnected from theory and practice, making it difficult to verify control strategies that combine virtual and real approaches.
It adopts a modular transparent chassis and digital twin technology, combining physical and digital prototypes, and realizes virtual-physical interaction through Matlab/Simulink control strategy. It integrates safety protection measures and supports a variety of interactive experiments.
The safety, intuitiveness, interactivity, and economy of the teaching equipment have been improved. Students can directly observe the internal structure and conduct various interactive experiments, which reduces costs and enhances learning effectiveness.
Smart Images
Figure CN121999673A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of new energy vehicle teaching equipment, specifically to a new energy electric vehicle experimental teaching device. Background Technology
[0002] In the field of new energy vehicle education, existing experimental equipment is often modified from traditional gasoline vehicles or directly uses mass-produced new energy vehicle models as teaching tools. These types of equipment generally have the following limitations:
[0003] 1. High Costs: Using mass-produced new energy vehicles not only requires huge initial investment but also incurs expensive maintenance costs. Furthermore, due to the rapid pace of vehicle upgrades, equipment may quickly become obsolete, making continuous upgrades prohibitively costly.
[0004] 2. Invisible internal structure: To ensure strength and aesthetics, mass-produced vehicles typically adopt a closed design, making it difficult for students to visually observe the working status and connection methods of internal components, resulting in a significant gap between theoretical knowledge and practical operation.
[0005] 3. High-voltage safety hazards: The high-voltage batteries and motor systems of new energy vehicles pose potential safety hazards, especially in teaching environments where students lack the necessary professional training and direct contact with high-voltage components can easily lead to safety accidents.
[0006] 4. Disconnect between theory and practice: Existing teaching equipment often focuses on static display or linear teaching, lacking deep integration with modern vehicle control strategies, making it difficult for students to master the key technologies and control strategies of new energy vehicles in practice.
[0007] 5. Insufficient experimental flexibility: Traditional teaching equipment can usually only demonstrate specific teaching content, such as vehicle structure or simple dynamic characteristics, and cannot support simulation and experimentation under complex working conditions, thus limiting the breadth and depth of experiments.
[0008] 6. Traditional digital twin experimental teaching equipment can only drive the movement of the digital prototype based on the measurement data of the physical prototype. This teaching equipment can not only control the physical prototype with the control strategy model, but also drive the physical prototype with the control strategy model. By feeding back the measurement data of the physical prototype to the digital prototype, it can also realize the difference between the theoretical value of the digital prototype and the actual value of the physical prototype in the digital prototype.
[0009] The above problems seriously affect the teaching quality of new energy vehicle-related courses and students' learning experience. Therefore, there is an urgent need to develop a new type of experimental teaching device. It should be cost-effective, have a clear structural view, comprehensive safety protection measures, the ability to verify control strategies combining virtual and real methods, and high experimental flexibility, in order to overcome the limitations of traditional teaching equipment and promote the modernization of new energy vehicle education.
[0010] A search revealed application publication number CN213275888, which discloses a comprehensive experimental system for the three-electric system of a new energy vehicle. The system includes a test bench, a drive assembly, a loading assembly, wheels, and a measurement and control system. The drive assembly includes a test motor, a first gearbox, and a drive housing. A torque sensor is installed between the test motor and the first gearbox. The first gearbox is connected to the drive housing, and the drive housing is connected to two wheels. The loading assembly includes a loading motor and two friction rollers. The loading motor drives the two friction rollers to rotate. The two friction rollers are respectively positioned directly below and in contact with the corresponding wheels. The test motor, torque sensor, and loading motor are all connected to the measurement and control system. This platform can perform performance testing experiments on the power motor of new energy vehicles under various operating conditions. It has a simple overall structure, low cost, and is suitable for teaching use in universities and educational institutions.
[0011] While comparative patents primarily focus on simplified designs for physical testing platforms, they fail to address core issues related to visualization, safety, interactivity, and cost in teaching equipment. This invention, through the innovative integration of a modular transparent chassis and digital twin technology, enhances the safety, intuitiveness, interactivity, and cost-effectiveness of teaching equipment, overcoming the limitations of traditional technologies. This solution is not conventional, as it requires interdisciplinary integration (mechanical, electronic, and software) and customized design for specific teaching scenarios, thus transcending the limitations of traditional single-domain solutions. Summary of the Invention
[0012] This invention aims to solve the problems of the prior art mentioned above. It proposes an experimental teaching device for new energy electric vehicles. The technical solution of this invention is as follows:
[0013] A new energy electric vehicle experimental teaching device includes: a physical experimental teaching device, i.e., a physical prototype, and a digital prototype measurement and control system, i.e., a digital prototype; wherein, the physical prototype includes a vehicle chassis, a front wheel suspension, a rear wheel suspension, a drive device, and a steering system; the steering system is a power steering device with automatic and manual switching functions;
[0014] The digital prototype runs on a computer terminal and includes a digital twin model, a data acquisition module, and a virtual-real interaction control module. The digital twin model is a kinematic and dynamic simulation model established based on a three-dimensional model of a physics experimental teaching device. The data acquisition module is used to acquire sensor data of the actual operating parameters of the physical prototype in real time. The virtual-real interaction control module is used to send the Matlab / Simulink control strategy to both the physical prototype and the digital prototype, and to send the real-time sensor data of the actual operation of the physical prototype to the digital prototype.
[0015] The digital prototype is a digital twin model driven by a Matlab / Simulink control strategy and sensor data from the physical prototype acquired in real time through a data acquisition module. It can move according to the Matlab / Simulink control strategy and can make feedback adjustments based on the actual motion data collected from the physical prototype.
[0016] The advantages and beneficial effects of this invention are as follows:
[0017] 1. Highly Intuitive: The compact, modular chassis and digital prototype make the complex, invisible mechanical transmission and electrical principles clearly visible. The physical chassis uses some high-strength transparent materials, allowing students to directly observe the layout of internal components, the gear meshing of the front wheel steering mechanism, the operation of the motor, and the working principle of the rear axle differential. The digital prototype can display the working status of invisible components inside the physical device in real time, showing the direction and magnitude of movement between components, such as the real-time display of the rotation and revolution speed relationship of the planetary gears inside the differential. Combined with the physical prototype, this facilitates students' understanding of the internal structure and working principles of new energy vehicles, making learning easier and more accessible.
[0018] 2. Safe and reliable: The low-voltage teaching system eliminates the risks of high voltage at its core. It also has comprehensive safety protections, such as integrated insulation monitoring, leakage protection, and emergency stop switches, to ensure the personal safety of students during the teaching process. This solves the safety hazards that exist in traditional teaching where experiments are conducted directly on real high-voltage vehicle systems.
[0019] 3. High interactivity: The virtual-physical integrated measurement and control system supports various interactive experiments such as parameter adjustment, fault injection, and performance testing, transforming passive observation into active exploration. On the physical chassis, students can adjust tire pressure, the damping coefficient of the telescopic shock absorber, etc.; on the digital prototype, the teacher can inject preset faults into the physical device or digital prototype through the measurement and control system, such as sensor signal drift and communication interruption. Students can diagnose and troubleshoot based on the phenomena on both the virtual and physical platforms, greatly enhancing student participation and learning outcomes.
[0020] 4. Comprehensive Functions: One set of equipment can cover comprehensive experiments for multiple courses such as "Automotive Structure", "Electric Vehicle Technology", "Automotive Theory" and "Automotive Testing and Diagnosis". At the same time, it can enhance students' understanding of structures and cultivate their innovative spirit. For example, the steering structure cleverly uses a combination sleeve to automatically switch between manual and automatic control. This can meet the multifaceted needs of new energy vehicle teaching and provide a comprehensive experimental platform for teaching.
[0021] 5. Reduced Costs: Compared to purchasing multiple physical vehicles, this teaching device is more cost-effective and durable. For example, the mainstream structure of current switchable steering devices is an electromagnetic clutch plus a motor, but the electromagnetic clutch and motor connection bear extremely high loads, making the electromagnetic clutch prone to burnout. In this structure, the electromagnet bears less load, resulting in better durability. It can also simultaneously meet the practical needs of a large number of students, solving the problem of expensive and scarce physical equipment in traditional teaching, which makes it difficult for students to disassemble, assemble, and measure in groups of several. Attached Figure Description
[0022] Figure 1 This is a structural diagram of the tram experimental teaching device according to a preferred embodiment of the present invention;
[0023] Figure 2 This is a diagram of the steering system structure;
[0024] Figure 3 This is a diagram of the rear axle drive unit.
[0025] Figure 4 This is a schematic diagram of a physics experiment teaching device (physics prototype).
[0026] The components include: drive unit-1; rear axle telescopic shock absorber-2; rear axle housing-3; connecting rod between rear axle housing and frame-4; frame-5; first connecting rod-6; steering tie rod-7; return spring-8; second connecting rod-9; third connecting rod-10; front axle telescopic shock absorber-11; fourth connecting rod-12; steering system-13; steering gear-14; steering rack-15; rack limit stop-16; and connecting rotating pair-17. Servo motor - 18; (Servo motor drive); Fourth spur gear - 19; Connecting sleeve with movable iron core - 20; Electromagnetic coil spring - 21; First spur gear - 22; Second spur gear - 23; Third spur gear - 24; Steering lever - 25; Fifth gear - 26; Motor - 27; Sixth gear - 28; Seventh gear - 29; Eighth gear - 30; Fifth link - 31; Steering wheel - 32; Torque sensor - 33; Steering column - 34. Detailed Implementation
[0027] The technical solutions of the embodiments of the present invention will be clearly and thoroughly described below with reference to the accompanying drawings. The described embodiments are merely some embodiments of the present invention.
[0028] The technical solution of the present invention to solve the above-mentioned technical problems is:
[0029] like Figure 1-3 As shown, a new energy electric vehicle experimental teaching device includes:
[0030] (1) Physics experiment teaching device (physics prototype) and digital prototype measurement and control system;
[0031] (2) The physical prototype includes a vehicle chassis, front wheel suspension, rear wheel suspension, drive unit and steering system;
[0032] (3) The digital prototype runs on a computer terminal and includes a digital twin model, a data acquisition module and a virtual-real interaction control module;
[0033] (4) The digital twin model is a kinematic and dynamic simulation model established based on the three-dimensional model of the physics experimental teaching device;
[0034] (5) The data acquisition module is used to acquire sensor data of the actual operating parameters of the physical prototype in real time, and the virtual-real interaction control module is used to send the Matlab / Simulink control strategy to the physical prototype and the digital prototype at the same time, and to send the sensor data of the actual operation of the physical prototype acquired in real time to the digital prototype.
[0035] (6) The digital prototype is a digital twin model driven by the Matlab / Simulink control strategy and the sensor data of the physical prototype acquired in real time through the data acquisition module. It can move according to the Matlab / Simulink control strategy and can make feedback adjustments based on the actual motion data collected by the physical prototype.
[0036] Preferably, the steering system includes: a steering wheel 32, a steering column 34, a torque sensor 33, a first spur gear 22, a second spur gear 23, a third spur gear 24, a steering rod 25, a servo motor 18, a fourth spur gear 19, a coupling sleeve 20 with a movable iron core, an electromagnetic coil spring 21, a steering tie rod 7, a return spring 8, a steering gear 14, a steering rack 15, and a rack limit stop 16. The steering wheel 32 and the steering column 34 are fixedly connected by the torque sensor 33. Torque sensor 33 measures the torque transmitted from steering wheel 32 to steering column 34; steering column 34 is fixedly connected to first spur gear 22, which is disconnected from second spur gear 23 along the axial direction and has no direct contact; second spur gear 23 is fixedly connected to steering rod 25; third spur gear 24 is a stepped spur gear with the upper gear radius larger than the lower gear radius; third spur gear 24 is loosely fitted on steering rod 25 and can rotate circumferentially relative to steering rod 25; fourth spur gear... Wheel 19 is fixed to the output shaft of servo motor 18, and the fourth spur gear 19 meshes with the pinion of the third spur gear 24. The parameters of the large gears of the first spur gear 22, the second spur gear 23, and the third spur gear 24 are consistent. The tooth profile of the coupling sleeve 20 with a movable iron core can mesh with the large gears of the first spur gear 22, the second spur gear 23, and the third spur gear 24. When the electromagnetic coil is de-energized, the large gears of the second spur gear 23 and the third spur gear 24 are circumferentially locked through the coupling sleeve 20 with a movable iron core. When the coil is energized, the coupling sleeve 20 with the movable iron core moves upward. At this time, the large gears of the first spur gear 22 and the second spur gear 23 are circumferentially locked through the coupling sleeve 20 with the movable iron core. The coupling sleeve has the function of moving up and down to switch the meshing state. The steering gear 14 is fixedly connected below the steering rod 25. The steering gear 14 meshes with the steering rack 15. The rotation of the steering gear 14 will drive the steering rack 15 to move left and right. The left and right movement of the steering rack 15 will drive the front wheel to steer through the steering tie rod 7.
[0037] Preferably, when the electromagnetic coil is de-energized, the engaging sleeve 20 with the movable iron core is in the lower position under the action of gravity or the return spring, so that the engaging sleeve 20 with the movable iron core simultaneously meshes with the large gears of the second spur gear 23 and the third spur gear 24. At this time, the power of the servo motor is transmitted to the steering rod 25 through the fourth spur gear 19, the small gear of the third spur gear 24, the large gear of the third spur gear 24, the engaging sleeve 20 with the movable iron core, and the second spur gear 23, so as to realize automatic assisted driving steering.
[0038] When the torque sensor 33 detects that the steering wheel torque is greater than the preset threshold of 5 Nm, the microcontroller controls the electromagnetic coil to be energized, attracting the coupling sleeve 20 with the movable iron core to move upward, so that it meshes with the first spur gear 22 and the second spur gear 23, and disengages from the large gear of the third spur gear 24. At this time, the torque of the steering wheel is directly transmitted to the steering rod 25 through the torque sensor 33, the steering column 34, the first spur gear 22, the coupling sleeve 20 with the movable iron core, and the second spur gear 23, so as to realize manual steering.
[0039] Preferably, the system is in "assisted driving mode" by default (i.e., the coil is de-energized). When the student turns the steering wheel, the change in the output voltage signal of the torque sensor is sampled by the ADC and the comparator determines whether the torque is greater than 5 Nm. If so, a high level is output to the relay, causing the electromagnet to engage, the coupling sleeve to move upward, and the system enters "mechanical takeover mode".
[0040] Preferably, the method for constructing and operating the digital prototype measurement and control system includes:
[0041] (1) Step S1: Use 3D modeling software to create a 3D model of the physical device and separate the parts into independent links according to the motion logic;
[0042] (2) Step S2: Convert the three-dimensional model into a URDF format description file, define the mass properties and moment of inertia of the link, and configure the type, limit position and damping coefficient of the joint;
[0043] (3) Step S3: Load the URDF file in the Gazebo simulation environment of the ROS operating system to generate a digital twin model that is consistent with the geometric and kinematic characteristics of the physical device;
[0044] (4) Establish multi-dimensional communication links between the control model and the digital prototype, the control model and the physical prototype, and the physical prototype and the digital prototype;
[0045] (5) The control strategy model and the physical prototype are connected by STLINK V2.1 downloader, and a virtual serial port is added to realize direct connection with the lower STM32F407 controller; by modifying the control model parameters, the execution result of the physical prototype can be seen immediately, and the execution result of the physical prototype can also be directly displayed in real time by adding the corresponding measurement module to the control strategy model.
[0046] Preferably, the specific implementation method of the communication link is as follows:
[0047] (1) The overall control strategy of the system is built using numerical calculation software. The numerical calculation software is configured as a ROS client node through the local area network communication protocol and connected to the master node of the ROS system to realize the sending and receiving of control commands. The specific implementation process is as follows:
[0048] 1) Build the overall system control strategy using Matlab / Simulink;
[0049] 2) In the ROS system, start the node manager with the command: roscore. In the new ROS terminal, use the ifconfig command to find the virtual machine's IP address, for example, http: / / 192.168.0.117:11311 / ;
[0050] 3) Specify the location of the ROS master node in the Matlab command window with the command: setenv('ROS_MASTER_URI', 'http: / / 192.168.0.117:11311 / ');
[0051] 4) Initialize the Matlab ROS client node with the command: rosinit;
[0052] (2) Communication between control model and physical prototype: STLINK v2.1 downloader is used for connection, and a virtual serial port is added to realize direct connection with the lower STM32F407 controller; by modifying the control model parameters, the execution result of the physical prototype can be seen immediately, and the execution result of the physical prototype can also be directly displayed in real time by adding the corresponding measurement module to the control strategy model;
[0053] Communication between physical and digital prototypes: The underlying sensor data of the physical prototype is acquired by STM32F407 and sent via WIFI through the ESP32 development board. The data is received by the digital prototype via WIFI through the ESP32 development board. The digital prototype subscribes to the data topic in ROS and drives the model movement in the simulation environment through the joint_state_publisher.
[0054] The actual state of the physical prototype is transmitted to the digital prototype through speed and position sensors. Feedback correction is performed on the differences between the digital prototype and the physical prototype. The digital prototype can display the control model parameters, physical prototype parameters, and the actual parameters of the current virtual prototype in real time.
[0055] Preferably, the rear wheel suspension adopts an integral structure, the drive unit 1 is located in the middle of the rear axle, and the drive unit includes a motor 27, a reducer composed of a fifth gear 26 and a sixth gear 28, and a differential composed of a seventh gear 29 and an eighth gear 30.
[0056] The rear axle cylindrical shock absorber 2, the rear axle housing 3, the frame 5, and the support rod 4 are all connected by a rotating pair to form a triangular linkage mechanism, which restricts longitudinal displacement.
[0057] The rear axle cylindrical shock absorber has strain gauges attached to its surface to measure the dynamic load on the suspension caused by road excitation. The motor 27 drives the fifth gear 26 to rotate. The fifth gear 26 meshes with the sixth gear 28 to form a reducer. The fifth link 31 is fixed to the inner side of the sixth gear 28. The eighth gear 30 is installed near the center of the large gear on the fifth link 31. The eighth gear 30 can rotate relative to the fifth link 31. The seventh gear 29 on both sides of the half shaft meshes with the eighth gear 30. The eighth gear 30 is the sun gear of the differential. It can rotate around the axis of the fifth link 31 and also revolve with the rotation of the sixth gear 28. The angular velocity of the eighth gear 30 is equal to the angular velocity of the sixth gear 28.
[0058] Preferably, the driving device integrates a sensor device, and its structural features are as follows:
[0059] (1) The speed measuring device includes an encoder mounted on the side of the motor output shaft;
[0060] (2) The status of each switch and the real-time measurement data are collected by the STM32F407 microcontroller and fed back to the digital prototype measurement and control system to calculate the real vehicle status and the difference between the real vehicle status and the physical prototype of the control strategy model. The speed of the virtual prototype is adjusted according to the positive and negative value and the magnitude of the difference.
[0061] Real-world vehicle condition measurement data not only provides real-time speed feedback for the digital prototype but also synchronizes the control strategy model data to the physical prototype via the ROS communication mechanism, forming a closed-loop control. Combining multi-source sensor information such as motor current and suspension dynamic load, the system can dynamically correct simulation parameters, improving the mapping accuracy of the digital prototype to real-world conditions and effectively supporting experimental teaching content such as drive control, energy consumption analysis, and suspension characteristics of new energy electric vehicles. Through real-time data interaction between the digital prototype and the physical device, the system can accurately reproduce the dynamic response characteristics of the vehicle under different road surface excitations. Combined with the MATLAB / Simulink co-simulation environment, the control strategy model can adaptively adjust PID parameters based on the deviation between the measured rotational speed and the target vehicle speed, achieving closed-loop optimization of the drive torque. Simultaneously, based on the suspension dynamic load data collected by strain gauges, the vehicle's vertical vibration acceleration can be inverted, further verifying the rationality of the damping characteristics and stiffness matching of the suspension system. All sensor information is timestamped and message published through ROS middleware, ensuring that the digital prototype's state update latency is less than 50ms, guaranteeing the real-time performance and stability of virtual-real synchronization. During the experiment, the system can dynamically switch between different road conditions to simulate typical vibration modes during vehicle operation. Through bidirectional feedback between the digital prototype and the physical device, coordinated observation of vehicle speed response and suspension dynamic characteristics is achieved. The speed data collected from the actual vehicle not only supports real-time correction of the closed-loop control strategy but also provides students with an intuitive basis for understanding the nonlinear characteristics of the drive system. Combining multi-source sensor information fusion, the teaching platform can recreate complex dynamic behaviors in real driving scenarios, strengthening the deep integration of theory and practice. Based on the tightly coupled architecture of the digital prototype and the physical device, the system achieves rapid synchronous response between virtual simulation and physical equipment, ensuring a high degree of consistency between control commands and physical feedback. Speed, torque, and vibration data published through ROS can be subscribed to in real time on a 3D visualization interface, intuitively presenting the evolution of vehicle dynamic behavior. This architecture supports fault injection experiments and extreme condition simulations, improving teaching safety and repeatability, while providing a high-fidelity testing environment for the verification of intelligent driving algorithms.
[0062] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions.
[0063] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0064] The above embodiments should be understood as illustrative only and not as limiting the scope of protection of the present invention. After reading the description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent changes and modifications also fall within the scope defined by the claims of the present invention.
Claims
1. A new energy electric vehicle experimental teaching device, characterized in that, include: The physics experiment teaching device is a physics prototype, and the digital prototype measurement and control system is a digital prototype; wherein, the physics prototype includes a vehicle chassis, front wheel suspension, rear wheel suspension, drive device and steering system; the steering system is a power steering device with automatic and manual switching function; The digital prototype runs on a computer terminal and includes a digital twin model, a data acquisition module, and a virtual-real interaction control module. The digital twin model is a kinematic and dynamic simulation model established based on a three-dimensional model of a physics experimental teaching device. The data acquisition module is used to acquire sensor data of the actual operating parameters of the physics prototype in real time. The virtual-real interaction control module is used to send the Matlab / Simulink control strategy to both the physics prototype and the digital prototype, and to send the real-time sensor data of the actual operation of the physics prototype to the digital prototype. The digital prototype is a digital twin model driven by a Matlab / Simulink control strategy and sensor data from the physical prototype acquired in real time through a data acquisition module. It can move according to the Matlab / Simulink control strategy and can make feedback adjustments based on the actual motion data collected from the physical prototype.
2. The experimental teaching device for new energy electric vehicles according to claim 1, characterized in that, The steering system includes: a steering wheel (32), a steering column (34), a torque sensor (33), a first spur gear (22), a second spur gear (23), a third spur gear (24), a steering rod (25), a servo motor (18), a fourth spur gear (19), a coupling sleeve (20) with a movable iron core, an electromagnetic coil spring (21), a steering tie rod (7), a return spring (8), a steering gear (14), a steering rack (15), and a rack limit stop (16). The steering wheel (32) and the steering column (34) are connected by the torque sensor (33). The torque sensor (33) is fixedly connected to the steering column (34) and can measure the torque transmitted from the steering wheel (32) to the steering column (34). The steering column (34) is fixedly connected to the first spur gear (22), and the first spur gear (22) is disconnected from the second spur gear (23) along the axial direction and has no direct contact. The second spur gear (23) is fixedly connected to the steering rod (25). The third spur gear (24) is a stepped spur gear with the upper gear radius being larger than the lower gear radius. The third spur gear (24) is loosely fitted on the steering rod (25) and can rotate circumferentially relative to the steering rod (25). The fourth spur gear (19) is fixed on the output shaft of the servo motor (18), and the fourth spur gear (19) meshes with the pinion of the third spur gear (24). The parameters of the large gears of the first spur gear (22), the second spur gear (23), and the third spur gear (24) are consistent. The tooth profile of the coupling sleeve (20) with the movable iron core can mesh with the large gears of the first spur gear (22), the second spur gear (23), and the third spur gear (24). When the electromagnetic coil is de-energized, the large gears of the second spur gear (23) and the third spur gear (24) are circumferentially locked by the coupling sleeve (20) with the movable iron core. When the electromagnetic coil is energized, the coupling sleeve (20) with the movable iron core moves upward. At this time, the large gears of the first spur gear (22) and the second spur gear (23) are circumferentially locked by the coupling sleeve (20) with the movable iron core. The coupling sleeve has the function of moving up and down to switch the meshing state. The steering gear (14) is fixedly connected below the steering rod (25). The steering gear (14) meshes with the steering rack (15). The rotation of the steering gear (14) will drive the steering rack (15) to move left and right. The left and right movement of the steering rack (15) will drive the front wheel to turn through the steering tie rod (7).
3. The experimental teaching device for new energy electric vehicles according to claim 2, characterized in that, When the electromagnetic coil is de-energized, the connecting sleeve (20) with the movable iron core is in the lower position under the action of gravity or the return spring, so that the connecting sleeve (20) with the movable iron core meshes with the large gear of the second spur gear (23) and the third spur gear (24) at the same time. At this time, the power of the servo motor is transmitted to the steering rod (25) through the small gear of the third spur gear (24), the large gear of the third spur gear (24), the connecting sleeve (20) with the movable iron core, and the second spur gear (23), so as to realize automatic assisted driving steering. When the torque sensor (33) detects that the steering wheel torque is greater than the preset threshold of 5 Nm, the microcontroller controls the electromagnetic coil to be energized, attracting the coupling sleeve (20) with the movable iron core to move upward, so that it meshes with the first spur gear (22) and the second spur gear (23), and disengages from the large gear of the third spur gear (24). At this time, the torque of the steering wheel is directly transmitted to the steering rod (25) through the torque sensor (33), steering column (34), first spur gear (22), coupling sleeve (20) with movable iron core and second spur gear (23), realizing manual steering.
4. The experimental teaching device for new energy electric vehicles according to claim 3, characterized in that, The system defaults to "assisted driving mode" (i.e., the coil is de-energized). When the student turns the steering wheel, the change in the voltage signal output by the torque sensor is sampled by the ADC and the comparator determines whether the torque is greater than 5 Nm. If so, a high level is output to the relay, causing the electromagnet to engage, the coupling sleeve to move upward, and the system enters "mechanical takeover mode".
5. The experimental teaching device for new energy electric vehicles according to claim 1, characterized in that, The construction and operation method of the digital prototype measurement and control system includes: (1) Step S1: Use 3D modeling software to create a 3D model of the physical device and separate the parts into independent links according to the motion logic; (2) Step S2: Convert the three-dimensional model into a URDF format description file, define the mass properties and moment of inertia of the link, and configure the type, limit position and damping coefficient of the joint; (3) Step S3: Load the URDF file in the Gazebo simulation environment of the ROS operating system to generate a digital twin model that is consistent with the geometric and kinematic characteristics of the physical device; (4) Establish multi-dimensional communication links between the control model and the digital prototype, the control model and the physical prototype, and the physical prototype and the digital prototype; (5) The control strategy model and the physical prototype are connected by STLINK V2.1 downloader, and a virtual serial port is added to realize direct connection with the lower STM32F407 controller.
6. The experimental teaching device for new energy electric vehicles according to claim 5, characterized in that, The specific implementation method of the communication link is as follows: (1) The overall control strategy of the system is built using numerical calculation software. The numerical calculation software is configured as a ROS client node through the local area network communication protocol and connected to the master node of the ROS system to realize the sending and receiving of control commands. The specific implementation process is as follows: 1) Build the overall system control strategy using Matlab / Simulink; 2) In the ROS system, start the node manager with the command: roscore. In the new ROS terminal, use the ifconfig command to find the virtual machine's IP address. 3) Specify the location of the ROS master node in the Matlab command window with the command: setenv('ROS_MASTER_URI', 'http: / / 192.168.0.117:11311 / '); 4) Initialize the Matlab ROS client node with the command: rosinit; (2) Communication between the control model and the physical prototype: The STLINK v2.1 downloader is used for connection, and a virtual serial port is added to realize direct connection with the lower-level STM32F407 controller; the execution results of the physical prototype can be seen immediately by modifying the control model parameters; Communication between physical and digital prototypes: The underlying sensor data of the physical prototype is acquired by STM32F407 and sent via WIFI through the ESP32 development board. The data is received by the digital prototype via WIFI through the ESP32 development board. The digital prototype subscribes to the data topic in ROS and drives the model movement in the simulation environment through the joint_state_publisher. The actual state of the physical prototype is transmitted to the digital prototype through speed and position sensors. Feedback correction is performed on the differences between the digital prototype and the physical prototype. The digital prototype can display the control model parameters, physical prototype parameters, and the actual parameters of the current virtual prototype in real time.
7. The experimental teaching device for new energy electric vehicles according to claim 1, characterized in that, The rear wheel suspension adopts an integral structure, and the drive unit (1) is located in the middle of the rear axle. The drive unit includes a motor (27), a reducer composed of the fifth gear (26) and the sixth gear (28), and a differential composed of the seventh gear (29) and the eighth gear (30). The rear axle cylindrical shock absorber (2), together with the rear axle housing (3), frame (5) and support rod (4), form a triangular linkage mechanism to limit longitudinal displacement; The rear axle cylindrical shock absorber (2) has strain gauges attached to its surface to measure the suspension dynamic load caused by road excitation; the motor (27) drives the fifth gear (26) to rotate, and the fifth gear (26) meshes with the sixth gear (28) to form a reducer. The fifth link (31) is fixedly connected to the inner side of the sixth gear (28). The eighth gear (30) is installed near the center of the large gear on the fifth link (31). The eighth gear (30) can rotate relative to the fifth link (31); meshing with the eighth gear (30) are the seventh gears (29) on both sides of the half shaft. The eighth gear (30) is the sun gear of the differential. It can rotate around the axis of the fifth link (31) and also revolve with the rotation of the sixth gear (28). The angular velocity of the eighth gear (30) is equal to the angular velocity of the sixth gear (28).