A prototype vehicle platform for steer-by-wire system testing and method of testing thereof

Abstract

The present application relates to a kind of for drive-by-wire steering system test prototype vehicle platform and its testing method, comprising: control chassis, road feeling simulation controller, vehicle controller, steering execution controller and power supply;Control chassis is used to after receiving the control signal sent by vehicle controller, according to the whole vehicle signal collected, utilizes preset drive-by-wire steering algorithm to control road feeling simulation controller and steering execution controller;Road feeling simulation controller is used to collect steering wheel corner, torque signal, while providing road feeling feedback to driver;Steering execution controller is used to collect rack displacement and speed signal, while tracking target rack displacement;Vehicle controller and control chassis, road feeling simulation controller and steering execution controller carry out information interaction, realize the control of entire prototype vehicle platform;Power supply is used to control chassis, road feeling simulation module controller, steering execution controller and vehicle controller power supply.The present application can be widely applied to vehicle control field.

Description

Technical Field

[0001] This invention relates to a prototype vehicle platform and its testing method for testing steer-by-wire systems, belonging to the field of vehicle control. Background Technology

[0002] Currently, relevant regulations allow for physical decoupling between the steering wheel and tires, eliminating the clutch between the steering wheel and pinion gear, thus leveraging the spatial flexibility of steer-by-wire. Furthermore, relevant standards also state that disconnecting the mechanical connection between the steering wheel and tires provides an unparalleled experience, such as reducing the number of steering wheel turns required for parking and U-turns; completely isolating unnecessary vibrations from the road surface and tires, optimizing driving feel; providing personalized road feel and steering response; and expanding advanced driver assistance functions to improve driving safety.

[0003] The mature application of steering functions in vehicles requires multiple stages, including software-in-the-loop testing, processor-in-the-loop testing, hardware-in-the-loop testing, and real-vehicle testing. Steer-by-wire has made significant progress in algorithms related to road feel simulation, steering execution, functional safety, and failure redundancy. Some researchers have also established hardware-in-the-loop testing platforms to verify steer-by-wire strategies. However, such platforms have several shortcomings: (1) they are difficult to provide drivers with realistic and effective motion feedback and road excitation feedback; (2) they are difficult to simulate real steering resistance torque; (3) the signals referenced by the control strategy, such as yaw rate and lateral acceleration, are too idealized, making it difficult to verify the robustness of the algorithm. Some researchers have also proposed strategies for signal transmission, algorithm operation, and control unit deployment in steer-by-wire systems within vehicles. However, researchers often overlook testing safety issues, testing procedures, complex signal acquisition, and rapid functional verification strategies for steer-by-wire during the prototype vehicle design phase or before mass production. Summary of the Invention

[0004] To address the aforementioned problems, the purpose of this invention is to provide a prototype vehicle platform and its testing method for testing steer-by-wire systems. This prototype vehicle platform is equipped with a steer-by-wire system and testing equipment, and can complete tasks such as signal acquisition, algorithm development, signal storage, and testing process testing within the steer-by-wire system.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a prototype vehicle platform for testing a steer-by-wire system, comprising:

[0007] Control cabinet, road feel simulation controller, vehicle controller, steering actuator controller, and power supply;

[0008] The control box is used to control the road feel simulation controller and the steering execution controller based on the collected vehicle signals after receiving the control signal sent by the vehicle controller;

[0009] The road feel simulation controller is used to collect steering wheel angle and torque signals, and at the same time provide road feel feedback to the driver;

[0010] The steering actuator controller is used to acquire rack displacement and speed signals, and simultaneously track the target rack displacement;

[0011] The vehicle controller interacts with the control box, road feel simulation controller and steering execution controller to realize the control of the entire prototype vehicle platform.

[0012] The power supply is used to power the control cabinet, the road feel simulation module controller, the steering actuator controller, and the vehicle controller.

[0013] Furthermore, the road feel simulation controller includes a road feel simulation control module, a steering angle torque sensor, a road feel simulation motor, and a first reducer. The steering angle torque sensor is used to collect steering wheel angle and torque signals and send them to the road feel simulation control module. Based on the steering wheel angle and torque information, the vehicle speed, yaw rate, and lateral acceleration information in the chassis CAN signal sent by the control box, and the rack force information estimated by the steering actuator controller, the road feel simulation control module uses a preset road feel simulation algorithm to calculate the torque required by the driver and simulates the corresponding road feel through the current vector control of the first reducer and the road feel simulation motor.

[0014] Furthermore, the steering actuator controller includes a steering actuator control module, a steering actuator motor, a second reducer, and a steering angle sensor; the steering angle sensor is used to acquire rack displacement and speed signals; the steering actuator control module is used to track the target rack displacement sent by the control chassis through a proportional-integral controller, a sliding diaphragm controller, or an optimal controller, based on the acquired rack displacement and speed information, using a preset variable transmission ratio strategy and a vehicle stability control strategy, and to achieve steering control through the second reducer and the steering actuator motor.

[0015] Furthermore, the control chassis includes a rapid prototyping control module, a vehicle signal acquisition module, a clutch control module, and external equipment; the vehicle signal acquisition module is used to acquire vehicle signals and send them to the rapid prototyping control module; the rapid prototyping control module processes the acquired signals based on a preset steer-by-wire algorithm to obtain target rack displacement information, which is then sent to the steering actuator controller, while simultaneously driving the clutch control module and the external equipment.

[0016] Furthermore, the vehicle signal acquisition module includes an amplifier, a left rack force sensor, a right rack force sensor, and an inertial navigation system; the left and right rack force sensors are used to acquire the rack force at the steering ball joint tie rod; the amplifier is used to amplify the acquired signals from the left and right rack force sensors and send them to the rapid prototyping controller; the inertial navigation system is used to measure the vehicle's longitudinal speed, yaw rate, lateral acceleration, and longitudinal acceleration signals, and to calibrate the corresponding sensor information in the vehicle.

[0017] Furthermore, the clutch control module includes a relay and a clutch. The relay is used to drive the clutch according to the control signal sent by the rapid prototyping controller, so that the clutch is disengaged during normal operation of the wire steering system and engaged in emergency situations or when the power is off, thereby re-establishing the mechanical connection between the steering wheel and the tires.

[0018] Furthermore, the external equipment includes a touch-sensitive host computer, LED lights, and a buzzer. The touch-sensitive host computer is used to display system information or fault information, and to input driver commands or configure vehicle controller parameters via touch. In conjunction with the LED lights and buzzer, it can provide the driver with auditory and visual feedback, respond to the driver's actions, and remind the driver of the current status of the system and system fault information.

[0019] Furthermore, the power supply is connected to the control chassis, road feel simulation module controller, steering execution controller and vehicle controller through a power control module, and the power control module converts the power supply's electrical energy into the power level required by each controller.

[0020] Furthermore, the prototype vehicle platform also includes a first shared CAN communication line, a second shared CAN communication line, a first proprietary CAN communication line, a second proprietary CAN communication line, and a CAN signal recorder; the first shared CAN communication line and the second shared CAN communication line are used for communication between the control chassis, the road feel simulation controller, the steering actuator controller, and the vehicle controller; the first proprietary CAN communication line and the second proprietary CAN communication line are used for communication between the control chassis, the road feel simulation controller, and the steering actuator controller; the CAN signal recorder is used to record the vehicle CAN signal, the road feel simulation controller's CAN signal, the steering actuator controller's CAN signal, and the control chassis's CAN signal.

[0021] Secondly, the present invention provides a testing method for a prototype vehicle platform for testing a steer-by-wire system, comprising the following steps:

[0022] A preset steer-by-wire algorithm is loaded into the control box, road feel simulation controller, and steering execution controller of the prototype vehicle platform;

[0023] Based on the prototype vehicle platform with the loading algorithm, a complete test was conducted, including six events: key sensing, door opening, vehicle start, engine shutdown, door closing, and key moving away, as well as five states: vehicle entry synchronization, vehicle entry assistance, operation, vehicle exit assistance, and vehicle exit synchronization.

[0024] The present invention has the following advantages due to the adoption of the above technical solutions:

[0025] (1) By mounting a steer-by-wire system and testing equipment on a prototype vehicle platform, and by setting up a control box, a road feel simulation controller and a steering execution controller, the present invention can complete the signal acquisition, algorithm development, signal storage and test process testing in the steer-by-wire system.

[0026] (2) The present invention loads a preset steer-by-wire algorithm into the road feel simulation controller, the steering execution controller and the control box, and stores the data of the test process through a CAN signal recorder, so that the performance of steer-by-wire can be analyzed online.

[0027] (3) The present invention is equipped with a vehicle signal acquisition module, which can acquire key signals and quickly verify the loading algorithm;

[0028] (4) The present invention uses a control box to drive external equipment and clutch, so that the clutch is disengaged during normal operation of the online steering system and engaged in emergency situations or power failures to re-establish the mechanical connection between the steering wheel and the tires, ensuring test safety.

[0029] (5) Since the steer-by-wire system of this invention has dual backups for the motor, sensor, communication, power supply and controller, it can ensure the safety of test personnel during the test process;

[0030] Therefore, this invention can be widely applied in the field of vehicle control. Attached Figure Description

[0031] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. In the drawings:

[0032] Figure 1 This is a schematic diagram of a prototype vehicle platform for testing a steer-by-wire system provided in an embodiment of the present invention;

[0033] Figure 2a and Figure 2b This is a schematic diagram of fault diagnosis and degradation provided in an embodiment of the present invention;

[0034] Figure 3 This is a timing diagram of a complete test of a steer-by-wire system provided in an embodiment of the present invention;

[0035] Figure 4a and Figure 4b This is a comparison diagram of the signals from the force sensor and the rack force observer provided in an embodiment of the present invention, wherein... Figure 4a This involves continuous sinusoidal driving at 20 km / h on an asphalt road. Figure 4b This involves continuous sinusoidal driving at 20 km / h on a cobblestone road;

[0036] Figure 5a and Figure 5b This is a comparison diagram of high-precision inertial navigation signals and vehicle signals provided in an embodiment of the present invention, wherein... Figure 5a It's a comparison of lateral acceleration. Figure 5b It's a comparison of yaw rate. Detailed Implementation

[0037] 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 only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0038] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0039] Because steer-by-wire has high functional safety requirements, and current hardware-in-the-loop testing platforms are insufficient to meet all the tests required for steer-by-wire systems before mass production, some embodiments of this invention provide a prototype vehicle platform for testing steer-by-wire systems, used to verify and develop steer-by-wire algorithms and advanced human-machine interaction functions.

[0040] Correspondingly, in other embodiments of the present invention, a testing method for a prototype vehicle platform for testing a steer-by-wire system is provided.

[0041] Example 1

[0042] like Figure 1As shown, this embodiment provides a prototype vehicle platform for testing a steer-by-wire system, comprising: a control chassis 27, a road feel simulation controller 28, a vehicle controller 15, a steering actuation controller 29, and a power supply 3. The control chassis 27, upon receiving a control signal from the vehicle controller 15, controls the road feel simulation controller 28 and the steering actuation controller 29 based on collected vehicle signals and a preset steer-by-wire algorithm. The road feel simulation controller 28 collects steering wheel angle and torque signals, and provides appropriate road feel feedback to the driver. The steering actuation controller 29 collects rack displacement and speed signals, and tracks the target rack displacement. The vehicle controller 15 interacts with the control chassis 27, the road feel simulation controller 28, and the steering actuation controller 29 to control the entire prototype vehicle platform. The power supply 3 provides power to the control chassis 27, the road feel simulation controller 28, the steering actuation controller 29, and the vehicle controller 15.

[0043] Preferably, the road feel simulation controller 28 includes a road feel simulation control module 5, a steering angle torque sensor 6, a road feel simulation motor 7, and a reducer 8. The steering angle torque sensor 6 is used to collect steering wheel angle and torque signals and send them to the road feel simulation control module 5. The road feel simulation control module 5, based on the steering wheel angle and torque information, vehicle speed / yaw rate / lateral acceleration information from the chassis CAN signal sent by the control housing 27 (transmitted by the rapid prototyping control module 25), and rack force information estimated by the steering actuator controller 29, uses a preset road feel simulation algorithm to calculate the torque required by the driver, and simulates the corresponding road feel through current vector control of the reducer 8 and the road feel simulation motor (which can be a permanent magnet synchronous motor).

[0044] Preferably, the steering actuator controller 29 includes a steering actuator control module 14, a steering actuator motor 13, a reducer 12, and a steering angle sensor 10. The steering angle sensor 10 is used to acquire rack displacement and speed signals. The steering actuator control module 14, based on the acquired rack displacement and speed information, uses a preset variable gear ratio strategy and vehicle stability control strategy to track the target rack displacement sent by the control housing 27 through a proportional-integral controller, a sliding diaphragm controller, or an optimal controller, and achieves steering control through the reducer 12 and the steering actuator motor 13.

[0045] Preferably, the control chassis 27 includes a rapid prototyping control module 25, a vehicle signal acquisition module, a clutch control module, and external equipment. The vehicle signal acquisition module acquires vehicle signals and sends them to the rapid prototyping control module 25. The rapid prototyping control module 25 processes the acquired signals based on a preset steer-by-wire algorithm to obtain target rack displacement information, which is then sent to the steering actuator controller 29. Simultaneously, it drives the clutch control module and the external equipment.

[0046] Preferably, the rapid prototyping control module 25 can run all or part of the algorithms for road feel simulation, variable gear ratio, steering execution, and human-machine interaction to accelerate the testing and optimization process of the steer-by-wire system algorithm. In other words, the functions of the road feel simulation control module 5 and the steering execution control module 14 can be deployed to the rapid prototyping control module 25, and after successful verification, they can be deployed to the corresponding road feel simulation control module 5 and steering execution control module 14.

[0047] Preferably, the vehicle signal acquisition module includes an amplifier 24, a left rack force sensor 11, a right rack force sensor 20, and a high-precision inertial navigation device 21. The left rack force sensor 11 and the right rack force sensor 20 are used to acquire the rack force at the steering ball joint tie rod; the amplifier 24 amplifies the signals acquired by the left rack force sensor 11 and the right rack force sensor 20 before sending them to the rapid prototyping controller 25; the high-precision inertial navigation device 21 measures the vehicle's longitudinal speed, yaw rate, lateral acceleration, longitudinal acceleration, and other signals, calibrating the corresponding sensor information in the vehicle.

[0048] In this embodiment, the rack force sensor and amplifier can reflect the steering resistance torque, road surface adhesion, road surface bumpiness, and abuse conditions (such as steering into the curb) in real time. At the same time, the collected data can verify the rationality of some of the road feel simulation control module and steering execution control module strategies.

[0049] Preferably, the clutch control module includes a relay 23 and a clutch 9. The relay 23 is used to drive the clutch 9 according to the control signal sent by the rapid prototyping controller 25, so that the clutch 9 is disengaged during normal operation of the steering system and engaged in emergency situations or when the power is off, so as to re-establish the mechanical connection between the steering wheel and the tires.

[0050] Preferably, the external equipment includes a touch-sensitive host computer 4, an LED light 26, and a buzzer 30. The touch-sensitive host computer 4 is used to display system information or fault information, and allows the driver to input commands or configure parameters of the vehicle controller. In conjunction with the LED light 26 and the buzzer 30, it can provide the driver with auditory and visual feedback, respond to the driver's actions, and remind the driver of the current status of the system and system fault information.

[0051] Preferably, the power supply 3 is connected to the control chassis 27, the road feel simulation module controller 28, the steering actuator controller 29, and the vehicle controller 15 via a power control module. The power control module converts the electrical energy from the power supply 3 into the required electrical energy level for each controller. Specifically, the power control module may include a DC-DC converter 1 and a fuse box 2. The DC-DC converter 1 is connected to the power supply 3 and each controller 25 via the fuse box 2, and is used to convert the electrical energy output from the power supply 3 into the voltage level required by the rapid prototyping controller 25, for example, providing 24V and 5V voltages to power some non-standard equipment or sensors; the fuse box 2 is used to ensure the safety of each power supply.

[0052] Preferably, the prototype vehicle platform further includes a first shared CAN communication line 18, a second shared CAN communication line 19, a first proprietary CAN communication line 16, a second proprietary CAN communication line 17, and a CAN signal recorder 22. The first shared CAN communication line 18 and the second shared CAN communication line 19 are used for communication between the control chassis 27, the road feel simulation controller 28, the steering actuation controller 29, and the vehicle controller 15; the first proprietary CAN communication line 16 and the second proprietary CAN communication line 17 are used for communication between the control chassis 27, the road feel simulation controller 28, and the steering actuation controller 29; and the CAN signal recorder 22 is used to record the vehicle CAN signal, the CAN signal of the road feel simulation controller 28, the CAN signal of the steering actuation controller 29, and the CAN signal of the rapid prototyping control module 25.

[0053] Preferably, such as Figure 2a and Figure 2b The diagram shown illustrates the fault diagnosis and degradation process in this embodiment. In this embodiment, both the road feel simulation control module 5 and the steering execution control module 14 contain two completely independent sets of components, A and B. Both the road feel simulation motor 7 and the steering execution motor 13 are dual three-phase motors, meaning that theoretically, the failure of one set is unrelated to the other. The steering torque sensor 6 (TAS) in the road feel simulation controller 28 and the steering angle sensor 10 (SAS) in the steering execution controller 29 each contain two sets of independently powered and independently output signals. The power supply 3 uses both sets of power (A and B). There are two private CAN communication lines 16 and 17 between the control chassis 27, the road feel simulation controller 28, and the steering execution controller 29, and two shared CAN communication lines 18 and 19 between the control chassis 27, the road feel simulation controller 28, and the steering execution controller 29. Therefore, the steer-by-wire system has dual backups for the motors, sensors, communication, power supply, and controllers, with two failure modes: single-point failure and complete failure.

[0054] S00 is the normal state; S10 is a single point of failure in vehicle CAN communication; S11 is a single point of failure in proprietary CAN communication; S12 is a single point of failure in the steering angle sensor; S13 is a single point of failure in the steering angle torque sensor; S20 is a single point of failure in the power supply; S21 is a single point of failure in the steering actuator motor; S22 is a single point of failure in the road feel simulation motor; S30 is a complete failure in the steering angle torque sensor but a valid position sensor in the road feel simulation motor; S31 is a complete failure in the steering angle sensor but a valid position sensor in the steering actuator motor; S32 is a complete failure in the road feel simulation motor; S33 is a complete failure in proprietary CAN communication but at least one channel of vehicle CAN communication is valid; S34 is a complete failure in vehicle CAN communication; S40 is a complete failure in the steering actuator motor, a complete failure in inter-vehicle communication, or the road feel simulation controller 28 has difficulty obtaining valid steering angle information.

[0055] On this test platform, vehicle safety needs further verification. If the vehicle encounters a serious S40 malfunction, the rapid prototyping control module 25 will control the relay 23 to engage the clutch 9, restoring the mechanical connection. It can also notify the vehicle controller 15 that the drive and braking systems can take appropriate measures, such as limiting drive capability, differential brake steering, or differential drive steering.

[0056] Example 2

[0057] Based on the prototype vehicle platform for testing the steer-by-wire system provided in Embodiment 1, this embodiment provides a testing method for the prototype vehicle platform for testing the steer-by-wire system, including the following steps:

[0058] 1) Load a preset steer-by-wire algorithm into the control box 27, the road feel simulation controller 28, and the steering execution controller 29;

[0059] 2) Based on the prototype vehicle platform after the algorithm is loaded, complete testing is carried out, including six events: key sensing, door opening, vehicle start, engine shutdown, door closing, and key away, as well as five states: vehicle entry synchronization, vehicle entry assistance, operation, vehicle exit assistance, and vehicle exit synchronization.

[0060] like Figure 3 The diagram shown is a timing diagram of a complete test of the prototype vehicle platform used for testing the steer-by-wire system according to the present invention.

[0061] When the vehicle senses the key approaching from the previous sleep cycle, it wakes up the road sense simulation control module 5, steering execution control module 14, and rapid prototyping control module 25 via the vehicle controller 15 network. The rapid prototyping control module 25 controls the relay 23 to open the clutch 9, and the road sense simulation control module 5 controls the steering wheel to synchronize with the wheel angle. At this time, the steering execution controller 14 does not move.

[0062] When the driver opens the car door, the road feel simulation control module 5 is in auxiliary mode, the steering wheel force feedback is relatively heavy (i.e., it provides a handle for the driver), and the steering execution control module 14 controls the steering gear to follow the steering wheel movement.

[0063] When the vehicle starts, the road feel simulation control module 5 and the steering execution control module 14 enter normal mode. The road feel simulation control module 5 receives road surface information and steering resistance torque from the steering execution control module 14 to form reasonable speed-sensitive steering characteristics.

[0064] When the vehicle is turned off, the road feel simulation control module 5 is in auxiliary mode, and the steering wheel force feedback is relatively heavy.

[0065] After the driver closes the car door, the road feel simulation control module 5 controls the steering wheel and the wheel angle to turn synchronously.

[0066] When the key is moved away, the road feel simulation control module 5, the steering execution control module 14, and the rapid prototyping control module 25 enter sleep mode, and the clutch re-engages.

[0067] Example 3

[0068] like Figure 4a and Figure 4b The image shows a comparison of the force sensor and rack force observer signals during continuous sinusoidal driving at 20 km / h on asphalt and cobblestone roads, respectively. In the test platform of this invention, installing a force sensor allows for the evaluation of the similarity between the rack force observer's amplitude and phase and the actual rack force.

[0069] like Figure 5a and Figure 5b The image shows a comparison between high-precision inertial navigation signals and vehicle signals. Lateral acceleration and yaw rate signals are crucial for evaluating the steering system; therefore, the vehicle testing platform proposed in this invention can effectively calibrate and compare signals collected by the vehicle's own sensors.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A prototype vehicle platform for testing a steer-by-wire system, characterized in that, include: Control cabinet, road feel simulation controller, vehicle controller, steering actuator controller, and power supply; The control box is used to control the road feel simulation controller and the steering execution controller based on the collected vehicle signals after receiving the control signal sent by the vehicle controller; The road feel simulation controller is used to collect steering wheel angle and torque signals, and at the same time provide road feel feedback to the driver; The steering actuator controller is used to acquire rack displacement and speed signals, and simultaneously track the target rack displacement; The vehicle controller interacts with the control box, road feel simulation controller and steering execution controller to realize the control of the entire prototype vehicle platform. The power supply is used to power the control cabinet, road feel simulation controller, steering actuator controller and vehicle controller; The road feel simulation controller includes a road feel simulation control module, a steering angle torque sensor, a road feel simulation motor, and a first reducer. The steering angle torque sensor is used to collect steering wheel angle and torque signals and send them to the road feel simulation control module. The road feel simulation control module calculates the torque required by the driver using a preset road feel simulation algorithm based on the steering wheel angle and torque information, the vehicle speed, yaw rate, and lateral acceleration information in the chassis CAN signal sent by the control box, and the rack force information estimated by the steering actuator controller. It then simulates the corresponding road feel through current vector control of the first reducer and the road feel simulation motor.

2. The prototype vehicle platform for testing a steer-by-wire system as described in claim 1, characterized in that, The steering actuator controller includes a steering actuator control module, a steering actuator motor, a second reducer, and a steering angle sensor. The steering angle sensor is used to collect rack displacement and speed signals. The steering actuator control module is used to track the target rack displacement sent by the control chassis through a proportional-integral controller, a sliding diaphragm controller, or an optimal controller, based on the collected rack displacement and speed information, using a preset variable transmission ratio strategy and a vehicle stability control strategy, and to achieve steering control through the second reducer and the steering actuator motor.

3. The prototype vehicle platform for testing a steer-by-wire system as described in claim 1, characterized in that, The control chassis includes a rapid prototyping control module, a vehicle signal acquisition module, a clutch control module, and external equipment. The vehicle signal acquisition module is used to acquire vehicle signals and send them to the rapid prototyping control module. The rapid prototyping control module processes the acquired signals based on a preset steer-by-wire algorithm to obtain target rack displacement information, which is then sent to the steering actuator controller. Simultaneously, it drives the clutch control module and the external equipment.

4. The prototype vehicle platform for testing a steer-by-wire system as described in claim 3, characterized in that, The vehicle signal acquisition module includes an amplifier, a left rack force sensor, a right rack force sensor, and an inertial navigation system. The left and right rack force sensors are used to acquire the rack force at the steering ball joint tie rod. The amplifier amplifies the acquired signals from the left and right rack force sensors and sends them to the rapid prototyping control module. The inertial navigation system measures the vehicle's longitudinal speed, yaw rate, lateral acceleration, and longitudinal acceleration signals, and calibrates the corresponding sensor information in the vehicle.

5. A prototype vehicle platform for testing a steer-by-wire system as described in claim 3, characterized in that, The clutch control module includes a relay and a clutch. The relay is used to drive the clutch according to the control signal sent by the rapid prototyping control module, so that the clutch is disengaged during normal operation of the online steering system and engaged in emergency situations or when the power is off, so as to re-establish the mechanical connection between the steering wheel and the tire.

6. A prototype vehicle platform for testing a steer-by-wire system as described in claim 3, characterized in that, The external equipment includes a touch-sensitive host computer, LED lights, and a buzzer. The touch-sensitive host computer is used to display system information or fault information, and to input driver commands or configure parameters of the vehicle controller via touch. In conjunction with the LED lights and buzzer, it can provide the driver with auditory and visual feedback, respond to the driver's actions, and remind the driver of the current status of the system and system fault information.

7. A prototype vehicle platform for testing a steer-by-wire system as described in claim 1, characterized in that, The power supply is connected to the control cabinet, road feel simulation controller, steering actuator controller and vehicle controller through a power control module. The power control module converts the power supply's electrical energy into the power level required by each controller.

8. A prototype vehicle platform for testing a steer-by-wire system as described in claim 1, characterized in that, The prototype vehicle platform also includes a first shared CAN communication line, a second shared CAN communication line, a first proprietary CAN communication line, a second proprietary CAN communication line, and a CAN signal recorder; the first shared CAN communication line and the second shared CAN communication line are used for communication between the control chassis, the road feel simulation controller, the steering actuator controller, and the vehicle controller. The first and second private CAN communication lines are used for communication between the control chassis, the road feel simulation controller, and the steering actuator controller; the CAN signal recorder is used to record the CAN signals of the whole vehicle, the CAN signals of the road feel simulation controller, the CAN signals of the steering actuator controller, and the CAN signals of the control chassis.

9. A testing method, implemented based on the prototype vehicle platform for testing steer-by-wire systems as described in claim 1, characterized in that, Includes the following steps: A preset steer-by-wire algorithm is loaded into the control box, road feel simulation controller, and steering execution controller of the prototype vehicle platform; Based on the prototype vehicle platform with the loading algorithm, a complete test was conducted, including six events: key sensing, door opening, vehicle start, engine shutdown, door closing, and key moving away, as well as five states: vehicle entry synchronization, vehicle entry assistance, operation, vehicle exit assistance, and vehicle exit synchronization.

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