A multi-domain collaborative rollover prevention control method for the steer-by-wire chassis of an electric transportation equipment

Abstract

The present invention discloses a multi-domain collaborative rollover prevention control method for a steer-by-wire chassis of an electric transport equipment, including the following steps: Step 1: Construct a rollover risk assessment and control strategy selection method by calculating key parameters such as the yaw rate and lateral acceleration of the vehicle in real time; Step 2: Based on the rollover risk index model and the rollover critical threshold in Step 1, establish a multi-domain collaborative rollover prevention control model by coordinating the independent steering, in-wheel motor differential steering, and ESP braking control system; Step 3: Based on the multi-domain collaborative rollover prevention control model in Step 2; Step 4: Based on the priority dynamic allocation and the control strategy execution result in Step 3, the central control unit uses a fuzzy logic control algorithm to coordinate the complex interaction relationships between subsystems. The present invention provides a method for the priority and usage frequency of reliable control strategies, providing a more reliable rollover prevention solution for electric transport equipment under complex dynamic working conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of wire-controlled chassis control for electric transportation equipment, and particularly to a multi-domain collaborative anti-rollover control method for the wire-controlled chassis of electric transportation equipment. Background Art

[0002] With the development of electric transportation equipment, wire-controlled chassis technology has gradually been applied in vehicle stability control. Especially in the fields of electric vehicles and driverless, due to its flexible maneuverability and high-precision control ability, wire-controlled chassis has become an important technical means to improve vehicle safety. However, in the actual driving process, the risk of vehicle rollover still exists. Especially when turning at high speed, avoiding obstacles emergently or in bad road conditions, when the lateral force of the vehicle is too large, rollover accidents are likely to occur. Traditional anti-rollover systems, such as Electronic Stability Program (ESP), mainly rely on braking force adjustment to prevent rollover. However, this single control method often performs inadequately in the face of complex dynamic working conditions and cannot effectively cope with various unstable factors.

[0003] In recent years, new technologies such as four-wheel independent steering and in-wheel motor differential steering have been introduced in electric transportation equipment. These technologies have brought new opportunities for anti-rollover control. In the existing anti-rollover control methods, most anti-rollover strategies only rely on a single control technology, such as Electronic Stability Program (ESP), active suspension system or differential braking, etc., and fail to fully integrate the advantages of multiple control technologies. This single-technology-dependent method often cannot achieve the best control effect when dealing with variable road conditions or emergencies, and it is difficult to meet the requirements of the vehicle's comprehensive dynamic performance under extreme working conditions. Although a few studies have tried to use multiple control technologies for anti-rollover control, these studies often lack a detailed discussion and optimization of the priority and usage frequency of different technical means in practical applications. Therefore, in order to improve the overall efficiency and adaptability of the anti-rollover system, there is an urgent need for an anti-rollover control method that can work collaboratively among multiple domains, achieve precise control of the vehicle's lateral force and yaw moment, and clarify the collaborative effect, priority ranking and dynamic adjustment mechanism of various control technologies in the comprehensive anti-rollover strategy, so as to improve the stability and safety of the vehicle under complex working conditions.

[0004] There have been many breakthroughs in the research on existing chassis rollover prevention control methods. For example, in the Chinese invention patent application No. CN201611254300.8, titled "A Rollover Prevention System and Its Control Method for a Four-Wheel Steering Vehicle", a method of rollover prevention control through the front-wheel differential braking module is proposed, and the original driving intention of the driver is maintained through the rear-wheel steering module, avoiding the secondary accidents that may be caused by not considering the driving intention during traditional rollover prevention control, enhancing the robustness of the system and minimizing the output of the controller; in the Chinese invention patent application No. CN201811557669.5, titled "A Vehicle Rollover Prevention Method Based on Model Predictive Control", this method compares the lateral load transfer ratio with a preset lateral load transfer ratio threshold, and adjusts the front-wheel steering angle of the vehicle and controls the braking forces of the four wheels according to the comparison result of the two to achieve rollover prevention control; in the Chinese invention patent application No. CN202011030509.2, titled "A Comprehensive Rollover Prevention Control Method for Distributed Drive Electric Vehicles", this method jointly controls through four control strategies including yaw stability control, roll stability control, decoupling control torque distribution strategy, and rollover prevention control based on differential braking, and simultaneously controls the driving force and braking force of the vehicle to achieve the comprehensive rollover prevention control of distributed drive electric vehicles; in the Chinese invention patent application No. CN201610552073.0, titled "A Rollover Prevention Control System for a Four-Wheel Steering Vehicle Incorporating Vehicle Speed Changes", this method adds a working condition discrimination unit, adopts multiple control modes, discriminates the working conditions according to parameters such as vehicle speed, wheel steering angle, and roll angular velocity, and adjusts the vehicle driving state through differential braking and the four-wheel steering actuator, and then changes the vehicle state to achieve the effect of suppressing rollover.

[0005] However, the above several rollover prevention control methods have the following two potential problems:

[0006] 1. Limitations of a single control domain: Although existing technologies such as the Chinese invention patent application No. CN201611254300.8: "A Rollover Prevention System and Its Control Method for a Four-Wheel Steering Vehicle" and the Chinese invention patent application No. CN201811557669.5: "A Vehicle Rollover Prevention Method Based on Model Predictive Control" enhance the vehicle stability through specific control strategies (such as differential braking and model predictive control), these methods mainly rely on a single control domain, such as the braking system or the steering system. This method that relies on a single control domain may not be able to provide comprehensive stability support when facing complex dynamic working conditions or variable road surface conditions. In addition, a single control means may not be able to fully utilize other potential control resources of the vehicle, such as the coordinated control of the suspension system or the power system, thus limiting the improvement of the overall rollover prevention performance.

[0007] 2. Lack of optimization of dynamic priority and usage frequency: In existing technologies such as Chinese Patent Application No. CN202011030509.2: "Integrated Anti-Rollover Control Method for Distributed Drive Electric Vehicles" and Chinese Patent Application No. CN201610552073.0: "An Anti-Rollover Control System for Four-Wheel Steering Vehicles Incorporating Vehicle Speed Changes", although the integrated use of multiple control strategies is proposed, these methods often lack a dynamic adjustment mechanism for the priority and usage frequency between different control strategies. During actual driving, a vehicle may face various emergency situations, and the system needs to be able to dynamically adjust the application of control strategies according to the real-time vehicle state and external environment to ensure the best anti-rollover effect under various working conditions. The lack of such dynamic adjustment ability may lead to waste of control resources or the inability to provide effective control at critical moments. Summary of the Invention

[0008] The purpose of this part is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Simplifications or omissions may be made in this part, as well as in the abstract and title of the present application, to avoid obscuring the purpose of this part, the abstract, and the title, and such simplifications or omissions shall not be used to limit the scope of the present invention.

[0009] In view of the problems existing in the above-mentioned existing multi-domain collaborative anti-rollover control method for the drive-by-wire chassis of electric transportation equipment, the present invention is proposed.

[0010] Therefore, the purpose of the present invention is to provide a multi-domain collaborative anti-rollover control method for the drive-by-wire chassis of electric transportation equipment. By integrating four-wheel independent steering, in-wheel motor differential steering, and the ESP system, a strategy for comprehensively regulating the lateral force and yaw moment of the vehicle is proposed, aiming to improve the driving stability and safety of the vehicle under high-speed turning, emergency obstacle avoidance, and complex road conditions. The multi-domain collaborative control strategy of the present invention breaks through the limitations of traditional single-domain control and provides a reliable method for the priority and usage frequency of control strategies, providing a more reliable anti-rollover solution for electric transportation equipment under complex dynamic working conditions.

[0011] To solve the above technical problems, the present invention provides the following technical solutions: A multi-domain collaborative anti-rollover control method for the drive-by-wire chassis of electric transportation equipment, comprising the following steps:

[0012] Step one: Construct a rollover risk assessment and control strategy selection method. By calculating key parameters such as the yaw angular velocity and lateral acceleration of the vehicle in real time, assess the rollover risk of the vehicle and establish a rollover risk index model; based on this model, combined with factors such as the center of gravity position, driving speed, and steering angle of the vehicle, determine whether the vehicle is approaching the rollover critical state and obtain the rollover critical threshold.

[0013] Step 2: Based on the rollover risk index model and the rollover critical threshold in Step 1, establish a multi-domain collaborative anti-rollover control model. Through the collaborative scheduling of the independent steering, in-wheel motor differential steering, and ESP braking control systems, active intervention in the rollover risk is achieved. Specifically, it includes adjusting the steering angles of the front and rear wheels through the four-wheel independent steering system to provide additional lateral force to balance the vehicle body, changing the yaw moment of the vehicle through the in-wheel motor differential steering system to help the vehicle regain stability, and at the same time, adjusting the braking force of each wheel by the ESP system to further optimize the yaw characteristics.

[0014] Step 3: Based on the multi-domain collaborative anti-rollover control model in Step 2, the central control unit dynamically allocates the control priorities of each subsystem. The central control unit sets and dynamically adjusts the priorities of the four-wheel independent steering system, in-wheel motor differential steering system, and ESP system by real-time monitoring and calculating the rollover risk index.

[0015] Step 4: Based on the priority dynamic allocation and the execution results of the control strategy in Step 3, the central control unit uses the fuzzy logic control algorithm to coordinate the complex interaction relationships between subsystems, ensuring the coordination of systems such as four-wheel independent steering and in-wheel motor differential steering under different working conditions. At the same time, through the adaptive control algorithm, according to the real-time state and historical data of the vehicle, the control parameters of each subsystem are dynamically adjusted, ultimately achieving precise control of multi-domain collaborative anti-rollover and improving the fault tolerance ability.

[0016] As a preferred solution of the multi-domain collaborative anti-rollover control method for the by-wire chassis of the electric transport equipment described in the present invention, wherein: Step 1 specifically includes:

[0017] 11) Based on the driving speed V and turning radius R of the vehicle, calculate the lateral acceleration ay of the vehicle for real-time evaluation of the rollover risk, as shown in the formula:

[0018]

[0019] 12) Based on the lateral acceleration ay in 11) and the yaw angular velocity ωz of the vehicle, combined with the center of gravity height hc of the vehicle, calculate the rollover risk index RRI, as shown in the formula, where α is the lateral acceleration coefficient and β is the yaw angular velocity coefficient:

[0020]

[0021] 13) Based on the RRI calculated in 12) and the center of gravity height h c 、body width w, and driving speed V of the vehicle, calculate the rollover critical threshold λ RRI , as shown in the formula, where k1 is the speed-related coefficient:

[0022]

[0023] As a preferred solution of the multi-domain collaborative anti-roll control method for the by-wire chassis of the electric transportation equipment described in the present invention, where: Step 2 specifically includes:

[0024] 21) Based on the roll risk index RRI in Step 1, adjust the steering angles of the front and rear wheels through the four-wheel independent steering system, as shown in the formula:

[0025] δ fl = δ0 + k fl ·RRI

[0026] δ fr = δ0 + k fr ·RRI

[0027] δ rl = δ0 - k rl ·RRI

[0028] δ rr = δ0 - k rr ·RRI

[0029] Where, δ0 is the current wheel steering angle, k fl is the cornering stiffness of the left front wheel, k fr is the cornering stiffness of the right front wheel, k rl is the cornering stiffness of the left rear wheel, k rr is the cornering stiffness of the right rear wheel;

[0030] 22) Based on the steering angles in 21), use the in-wheel motor differential system to adjust the yaw moment M z , of the vehicle through the torque difference ΔT, as shown in the formula, where k d is the controller gain parameter:

[0031]

[0032] 23) Based on the yaw moment M z and the yaw angular velocity ω z in 22), adjust the braking force F bi of each wheel through the ESP system, as shown in the formula:

[0033]

[0034] Where, Δω z is the change in yaw angular velocity, is the maximum yaw angular velocity, F z is the total vertical force of the vehicle, μ i is the braking force assist coefficient.

[0035] As a preferred solution of the multi-domain collaborative anti-rollover control method for the by-wire chassis of the electric transportation equipment described in the present invention, wherein: Step three specifically includes:

[0036] 31) Based on the RRI value in Step two and the importance of each subsystem, calculate the priority P of each subsystem i , as shown in the formula, where w i is the priority weight:

[0037] ............. 32) Based on the priority P in 31) i , dynamically adjust the control frequency f of each subsystem i , as shown in the formula, where f base is the base frequency of the subsystem, and k p is the priority coefficient:

[0039] f i = f base + k p ·P i

[0040] 33) Based on the control frequency f in 32) i , the central control unit sets the execution order according to the priority to ensure the fast response of the high-priority system.

[0041] As a preferred solution of the multi-domain collaborative anti-rollover control method for the by-wire chassis of the electric transportation equipment described in the present invention, wherein: Step four specifically includes:

[0042] 41) Based on the priority P in Step three i , use the fuzzy logic control algorithm to adjust the output of each subsystem to coordinate the overall stability of the vehicle. The fuzzy control output is as shown in the formula:

[0043]

[0044] 42) Based on the fuzzy control output in 41), use the adaptive control algorithm to adjust the control parameter θ of each subsystem in real time i , as shown in the formula, where γ is the RRI coefficient:

[0045]

[0046] 43) Based on the adaptive control algorithm in 42), combine historical data and real-time data to optimize the control strategy and improve the fault tolerance and adaptability of the system.

[0047] As a preferred solution of the multi-domain collaborative anti-rollover control method for the steer-by-wire chassis of the electric transportation equipment described in the present invention, wherein: the multi-domain collaborative anti-rollover control method for the steer-by-wire chassis of the electric transportation equipment is applied to the steer-by-wire chassis of the electric transportation equipment, including: an independent steering system, a hub motor differential steering system, an ESP braking stability control system, a chassis anti-rollover domain controller, and a power supply unit;

[0048] The independent steering system includes a steering motor, a steering motor controller, a secondary worm and worm gear reduction mechanism, a primary planetary gear reduction mechanism, a kingpin column, an angle sensor, a wheel, a steering knuckle, a frame, a bearing, and a chassis anti-rollover domain controller. The output shaft of the steering motor is connected to the input end of the primary planetary gear reduction mechanism. The primary planetary gear reduction mechanism is mechanically connected to the secondary worm and worm gear reduction mechanism. The secondary worm and worm gear reduction mechanism is connected to the kingpin column to ensure that the output torque of the steering motor is transmitted to the kingpin column through the worm, achieving precise control of the wheel steering. The upper end of the kingpin column is connected to the frame through a bearing, and the lower end is connected to the steering knuckle of the wheel. The steering knuckle is mechanically connected to the wheel. The angle sensor is installed at an appropriate position of the steering mechanical structure to monitor the angle of the kingpin column in real time and feed the data back to the steering motor controller. The steering motor controller transmits the data to the chassis anti-rollover domain controller to achieve closed-loop control;

[0049] The hub motor differential steering system includes a hub motor, a brake disc, a gear set primary reduction mechanism, a ball screw secondary reduction mechanism, a brake motor, a lower fork arm, a column, a steering arm, an upper fork arm, a shock absorber, and a frame mounting point. The hub motor is directly mechanically connected to the wheel. By controlling the speed of each hub motor, differential speed between different wheels is achieved, thereby achieving the effect of differential steering. The brake motor is mechanically connected to the gear set primary reduction mechanism. The ball screw secondary reduction mechanism is mechanically connected to the gear set primary reduction mechanism, and the ball screw secondary reduction mechanism is mechanically connected to the brake disc to achieve braking;

[0050] The ESP braking stability control system includes a brake motor, a ball screw reduction mechanism, sensors, hub motors, a brake disc assembly, a mechanical and electronic power booster mechanism, a multi-stage gear reduction mechanism, a brake controller, a brake pedal position sensor, a brake pedal, an accelerator pedal, an accelerator pedal position sensor, and a chassis anti-rollover domain controller. The brake motor is mechanically connected to the ball screw reduction mechanism. The ball screw reduction mechanism is mechanically connected to the mechanical and electronic power booster mechanism. The mechanical and electronic power booster mechanism is mechanically connected to the multi-stage gear reduction mechanism. The multi-stage gear reduction mechanism is connected to the brake disc assembly through a mechanical structure to provide braking force. The hub motor is mechanically embedded in the wheel. The sensors are installed on the wheel assembly for measuring the wheel speed;

[0051] The chassis rollover prevention domain controller includes a yaw rate sensor, a roll angle sensor, a central control unit, and a rollover suppression actuator; the yaw rate sensor and the roll angle sensor are arranged inside the vehicle to monitor the yaw rate and roll angle of the vehicle in real time and transmit the data to the central control unit; the central control unit analyzes the motion state of the vehicle based on the data provided by the sensors, determines whether there is a rollover risk, and calculates the corresponding rollover suppression strategy;

[0052] The power supply unit includes a power battery pack, a DC-DC converter, an energy management system, and a cable network; the power battery pack provides the main power for the entire by-wire chassis system, and the high-voltage electricity is converted into low-voltage electricity suitable for each subsystem through the DC-DC converter; the energy management system is responsible for monitoring and managing the charge and discharge state of the battery to ensure the stable operation of the power supply unit and distributes the electric energy to each subsystem through the cable network; the cable network connects the power supply unit with the independent steering system, the hub motor differential steering system, the ESP braking stability control system, and the chassis rollover prevention domain controller to ensure that each system obtains stable power supply.

[0053] As a preferred solution of the multi-domain collaborative rollover prevention control method for the by-wire chassis of the electric transport equipment according to the present invention, the column is mechanically connected to the brake motor, the upper part of the column is mechanically connected to the upper fork arm, and the lower part is mechanically connected to the lower fork arm; the lower end of the steering arm is mechanically connected to the upper fork arm and the lower fork arm, and the upper part of the steering arm is mechanically connected to the secondary worm and gear reduction mechanism; the lower end of the shock absorber is mechanically connected to the column, and the upper part is mechanically connected to the steering arm; the steering motor and the steering motor controller are integrally castings, the steering motor is mechanically connected to the primary planetary gear reduction mechanism, and the primary planetary gear reduction mechanism is mechanically connected to the secondary worm and gear reduction mechanism; the upper end of the secondary worm and gear reduction mechanism is mechanically connected to the frame mounting point; the steering motor controller is connected to the chassis rollover prevention domain controller through the CAN bus.

[0054] As a preferred solution of the multi-domain collaborative rollover prevention control method for the by-wire chassis of the electric transport equipment according to the present invention, the brake pedal position sensor and the accelerator pedal position sensor are mechanically installed on the brake pedal and the accelerator pedal, the brake pedal position sensor, the accelerator pedal position sensor and the brake controller are connected through the CAN bus, the brake controller and the mechanical and electronic power booster mechanism are connected through the CAN bus to control the braking force by sending and receiving signals, the brake controller and the chassis rollover prevention domain controller are connected through the CAN bus to receive control signals, and the wheel speed sensor is connected to the chassis rollover prevention domain controller through the CAN bus to receive signals.

[0055] As a preferred solution of the multi-domain collaborative rollover prevention control method for the steer-by-wire chassis of the electric transportation equipment described in the present invention, wherein: the rollover suppression actuator includes an electronic stabilizer bar, a hydraulic rollover suppressor and a control circuit, and the control signal generated by the central control unit drives the electronic stabilizer bar and the hydraulic rollover suppressor to work through the control circuit, adjusting the vehicle's suspension system and lateral support force to suppress the vehicle's rollover tendency.

[0056] Advantages of the present invention:

[0057] 1. The present invention calculates the lateral acceleration and rollover risk index in real time based on the vehicle's driving speed, turning radius, center of gravity height and yaw angular velocity. This evaluation model can dynamically reflect the rollover risk of the vehicle under different working conditions, enabling the system to quickly perceive and respond to the vehicle's state changes.

[0058] 2. By calculating the rollover critical threshold, it is possible to predict in advance the state of the vehicle approaching rollover and give an early warning signal. This makes the rollover prevention control forward-looking, enabling effective stability measures to be taken in advance and reducing the likelihood of accidents.

[0059] 3. The present invention combines four-wheel independent steering, in-wheel motor differential control and the ESP system, and dynamically adjusts the control parameters of each subsystem of the vehicle based on the rollover risk index calculated in real time. Through the coordinated operation of these subsystems, the stability of the vehicle is significantly improved, especially in extreme working conditions, effectively preventing the vehicle from getting out of control or rolling over.

[0060] 4. Through the priority dynamic allocation model, it is possible to adjust the execution order and frequency of control instructions in real time according to the contribution of each subsystem to the vehicle's stability. This mechanism ensures that when the rollover risk is high, the most critical subsystems are responded to first, optimizing the allocation of control resources and enhancing the vehicle's safety and response speed.

[0061] 5. The present invention introduces fuzzy logic control and adaptive control algorithms. Through the dynamic adjustment of fuzzy control rules, it can flexibly cope with different vehicle working conditions. At the same time, the adaptive control algorithm automatically optimizes the control parameters of each subsystem by learning historical data and real-time states, enhancing the system's self-learning ability and improving the vehicle's rollover prevention ability and adaptability.

[0062] 6. By combining fuzzy logic control and adaptive control algorithms, the present invention can not only self-optimize based on real-time adjustment of control strategies, but also maintain the stability and fault tolerance of the system under complex and changeable working conditions, effectively reducing the rollover risk caused by vehicle state changes or environmental changes. Description of the Drawings

[0063] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. Among them:

[0064] Figure 1 is the schematic diagram of the method of the present invention;

[0065] Figure 2 is the power supply unit architecture and subsystem relationship diagram proposed by the present invention;

[0066] Figure 3 is the independent steering system architecture diagram proposed by the present invention;

[0067] Figure 4 is the hub motor differential steering system architecture diagram proposed by the present invention;

[0068] Figure 5 is the ESP braking stability control system architecture diagram proposed by the present invention;

[0069] Figure 6 is the chassis anti-rollover domain controller architecture diagram proposed by the present invention. Specific Embodiments

[0070] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will make a detailed description of the specific embodiments of the present invention in conjunction with the drawings of the specification.

[0071] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0072] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that can be included in at least one implementation manner of the present invention. The "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that excludes other embodiments.

[0073] Furthermore, the present invention is described in detail in conjunction with schematic diagrams. When detailing the embodiments of the present invention, for the convenience of explanation, the cross-sectional views showing the device structure will be enlarged locally out of the general scale, and the schematic diagrams are only examples and should not limit the scope of protection of the present invention herein. In addition, in actual production, three-dimensional spatial dimensions including length, width, and depth should be included.

[0074] Refer toFigures 1-6 , a multi-domain collaborative rollover prevention control method for the by-wire chassis of an electric transportation equipment is provided, including the following steps:

[0075] Step 1: Construct a rollover risk assessment and control strategy selection method. By calculating key parameters such as the yaw angular velocity and lateral acceleration of the vehicle in real time, evaluate the rollover risk of the vehicle and establish a rollover risk index model; based on this model, combined with factors such as the center of gravity position, driving speed, and steering angle of the vehicle, determine whether the vehicle is approaching the rollover critical state and obtain the rollover critical threshold;

[0076] Step 2: Based on the rollover risk index model and rollover critical threshold in Step 1, establish a multi-domain collaborative rollover prevention control model. Through the coordinated scheduling of the independent steering, hub motor differential steering, and ESP braking control systems, achieve active intervention in the rollover risk; specifically, adjust the steering angles of the front and rear wheels through the four-wheel independent steering system to provide additional lateral force to balance the vehicle body, and change the yaw moment of the vehicle through the hub motor differential steering system to help the vehicle regain stability. At the same time, the ESP system adjusts the braking force of each wheel to further optimize the yaw characteristics;

[0077] Step 3: Based on the multi-domain collaborative rollover prevention control model in Step 2, the central control unit dynamically allocates the control priorities of each subsystem; the central control unit sets and dynamically adjusts the priorities of the four-wheel independent steering system, hub motor differential steering system, and ESP system by real-time monitoring and calculating the rollover risk index;

[0078] Step 4: Based on the priority dynamic allocation and control strategy execution results in Step 3, the central control unit uses the fuzzy logic control algorithm to coordinate the complex interaction relationships between subsystems, ensuring the coordination of systems such as four-wheel independent steering and hub motor differential steering under different working conditions; at the same time, through the adaptive control algorithm, according to the real-time state and historical data of the vehicle, dynamically adjust the control parameters of each subsystem, and finally achieve the precise control of multi-domain collaborative rollover prevention and the improvement of fault tolerance ability.

[0079] Among them, Step 1 specifically includes:

[0080] 11) Based on the driving speed V and turning radius R of the vehicle, calculate the lateral acceleration ay of the vehicle for real-time evaluation of the rollover risk, as shown in the formula:

[0081]

[0082] 12) Based on the lateral acceleration ay in 11) and the yaw angular velocity ωz of the vehicle, combined with the center of gravity height hc of the vehicle, calculate the rollover risk index RRI, as shown in the formula, where α is the lateral acceleration coefficient and β is the yaw angular velocity coefficient:

[0083]

[0084] 13) Based on the RRI calculated in 12) and the height h of the vehicle's center of gravity c , body width w, and driving speed V, calculate the rollover critical threshold λ RRI , as shown in the formula, where k1 is the speed-related coefficient:

[0085]

[0086] Further, step two specifically includes:

[0087] 21) Based on the rollover risk index RRI in step one, adjust the steering angles of the front and rear wheels through the four-wheel independent steering system, as shown in the formula:

[0088] δ fl = δ0 + k fl ·RRI

[0089] δ fr = δ0 + k fr ·RRI

[0090] δ rl = δ0 - k rl ·RRI

[0091] δ rr = δ0 - k rr ·RRI

[0092] where δ0 is the current wheel steering angle, k fl is the left front wheel cornering stiffness, k fr is the right front wheel cornering stiffness, k rl is the left rear wheel cornering stiffness, k rr is the right rear wheel cornering stiffness;

[0093] 22) Based on the steering angles in 21), use the in-wheel motor differential system to adjust the yaw moment M of the vehicle through the torque difference ΔT z , as shown in the formula, where k d is the controller gain parameter:

[0094]

[0095] 23) Based on the yaw moment M in 22) z and the yaw angular velocity ω z , adjust the braking force F of each wheel through the ESP system bi , as shown in the formula:

[0096]

[0097] Among them, Δω z is the yaw rate change, is the maximum yaw rate, F z is the total vertical force of the vehicle, μ i is the braking force assist coefficient.

[0098] Furthermore, step three specifically includes:

[0099] 31) Based on the RRI value in step two and the importance of each subsystem, calculate the priority P i of each subsystem, as shown in the formula, where w i is the priority weight:

[0100]

[0101] .............32) Based on the priority P i in 31), dynamically adjust the control frequency f i of each subsystem, as shown in the formula, where f base is the base frequency of the subsystem, and k p is the priority coefficient:

[0102] f i = f base + k p ·P i

[0103] 33) Based on the control frequency f i in 32), the central control unit sets the execution order according to the priority to ensure the fast response of the high-priority system.

[0104] Among them, step four specifically includes:

[0105] 41) Based on the priority P i in step three, use the fuzzy logic control algorithm to adjust the output of each subsystem to coordinate the overall stability of the vehicle. The fuzzy control output is as shown in the formula:

[0106]

[0107] 42) Based on the fuzzy control output in 41), use the adaptive control algorithm to adjust the control parameter θ i of each subsystem in real time, as shown in the formula, where γ is the RRI coefficient:

[0108]

[0109] 43) Based on the adaptive control algorithm in 42), combine historical data with real-time data to optimize the control strategy and improve the fault tolerance and adaptability of the system.

[0110] Specifically, the multi-domain collaborative anti-rollover control method for the drive-by-wire chassis of an electric transportation equipment is applied to the drive-by-wire chassis of an electric transportation equipment, and includes: an independent steering system 4, a hub motor differential steering system 5, an ESP braking stability control system 6, a chassis anti-rollover domain controller 7, and a power supply unit;

[0111] Among them, the independent steering system includes a steering motor 401, a steering motor controller 405, a secondary worm and worm gear reduction mechanism 402, a primary planetary gear reduction mechanism 411, a kingpin column 403, a corner sensor 406, a wheel 404, a steering knuckle 410, a vehicle frame 408, a bearing 409, and a chassis anti-rollover domain controller 407. The output shaft of the steering motor 401 is connected to the input end of the primary planetary gear reduction mechanism 411. The primary planetary gear reduction mechanism 411 is mechanically gear-connected to the secondary worm and worm gear reduction mechanism 402. The secondary worm and worm gear reduction mechanism 402 is connected to the kingpin 403 column, ensuring that the output torque of the steering motor 401 is transmitted to the kingpin column 403 through the worm, realizing precise control of the steering of the wheel 404. The upper end of the kingpin column 403 is connected to the vehicle frame 408 through a bearing 409, and the lower end is connected to the steering knuckle 410 of the wheel 404. The steering knuckle 410 is fixedly connected to the wheel 404. The corner sensor 406 is installed at an appropriate position of the steering mechanical structure, used to monitor the corner of the kingpin column 403 in real time, and feedback the data to the steering motor controller 405. The steering motor controller 405 transmits the data to the chassis anti-rollover domain controller 407 to achieve closed-loop control;

[0112] Among them, the in-wheel motor differential steering system 5 includes an in-wheel motor 501, a brake disc 502, a gear set primary reduction mechanism 504, a ball screw secondary reduction mechanism 503, a brake motor 505, a lower fork arm 506, a column 507, a steering arm 508, an upper fork arm 509, a shock absorber 510, and a frame mounting point 511; the in-wheel motor 501 is directly mechanically connected to the wheel 404, and by controlling the rotational speed of each in-wheel motor 501, differential speed between different wheels 404 is achieved, thus achieving the effect of differential steering; the brake motor 505 is mechanically gear-connected to the gear set primary reduction mechanism 504, the ball screw secondary reduction mechanism 503 is mechanically gear-connected to the gear set primary reduction mechanism 504, and the ball screw secondary reduction mechanism 503 is fixedly connected to the brake disc 502 to achieve braking; further, the column 507 is fixedly connected to the brake motor 505, the upper section of the column 507 is mechanically connected to the upper fork arm 509, and the lower end is mechanically connected to the lower fork arm 506; the lower end of the steering arm 508 is mechanically connected to the upper fork arm 509 and the lower fork arm 506, and the upper section of the steering arm 508 is mechanically connected to the secondary worm and gear reduction mechanism 402; the lower end of the shock absorber 510 is fixedly connected to the column 507, and the upper section is mechanically connected to the steering arm 508; the steering motor 401 and the steering motor controller 405 are integrally castings, the steering motor 401 is gear-connected to the primary planetary gear reduction mechanism 411, and the primary planetary gear reduction mechanism 411 is mechanically gear-connected to the secondary worm and gear reduction mechanism 402; the upper end of the secondary worm and gear reduction mechanism 402 is fixedly connected to the frame mounting point 511; the steering motor controller 405 is connected to the chassis rollover prevention domain controller 407 via the can bus.

[0113] Among them, the ESP braking stability control system 6 includes a braking motor 601, a ball screw reduction mechanism 602, a sensor 603, a hub motor 604, a brake disc assembly 605, a mechanical and electronic force amplification mechanism 606, a multi-stage gear reduction mechanism 607, a brake controller 612, a brake pedal position sensor 608, a brake pedal 609, an accelerator pedal 610, an accelerator pedal position sensor 611, and a chassis rollover prevention domain controller 613; the braking motor 601 is mechanically connected to the ball screw reduction mechanism 602, the ball screw reduction mechanism 602 is fixedly connected to the mechanical and electronic force amplification mechanism 606, the mechanical and electronic force amplification mechanism 606 is mechanically gear-connected to the multi-stage gear reduction mechanism 607, and the multi-stage gear reduction mechanism 607 is mechanically gear-connected to the brake disc assembly 605 to provide braking force. The hub motor 604 is mechanically embedded in the wheel 404, and the sensor 603 is installed on the wheel assembly for measuring the wheel speed; further, the brake pedal position sensor 608 and the accelerator pedal position sensor 611 are mechanically installed on the brake pedal 609 and the accelerator pedal 610. The brake pedal position sensor 608, the accelerator pedal position sensor 611, and the brake controller 612 are connected through the can bus. The brake controller 612 is connected to the mechanical and electronic force amplification mechanism 606 through the can bus to control the braking force by sending and receiving signals. The brake controller 612 is connected to the chassis rollover prevention domain controller 613 through the can bus to receive control signals. The wheel speed sensor is connected to the chassis rollover prevention domain controller 613 through the can bus to receive signals.

[0114] Specifically, the power supply unit includes a power battery pack 1, a DC-DC converter 2, an energy management system 3, and a cable network; the power battery pack 1 provides the main power for the entire by-wire chassis system, and the high-voltage electricity is converted into low-voltage electricity suitable for each subsystem through the DC-DC converter 2; the energy management system 3 is responsible for monitoring and managing the charge and discharge status of the battery, ensuring the stable operation of the power supply unit, and distributing the electric energy to each subsystem through the cable network; the cable network connects the power supply unit to the independent steering system 4, the hub motor differential steering system 5, the ESP braking stability control system 6, and the chassis rollover prevention domain controller 7 to ensure that each system obtains stable power supply.

[0115] Among them, the chassis rollover prevention domain controller 7 includes a yaw rate sensor 701, a roll angle sensor 702, a central control unit 703, and a rollover suppression actuator; the yaw rate sensor 701 and the roll angle sensor 702 are arranged in the vehicle to real-time monitor the yaw rate and roll angle of the vehicle and transmit the data to the central control unit 703; based on the data provided by the sensors, the central control unit 703 analyzes the motion state of the vehicle, judges whether there is a rollover risk, and calculates the corresponding rollover suppression strategy;

[0116] Specifically, the rollover suppression actuator includes an electronic stabilizer bar 705, a hydraulic rollover suppressor 706, and a control circuit 704. The control signal generated by the central control unit 703 drives the electronic stabilizer bar 705 and the hydraulic rollover suppressor 706 to work, adjusting the vehicle's suspension system and lateral support force to suppress the vehicle's rollover tendency.

[0117] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A multi-domain coordinated rollover prevention control method for a wire-controlled chassis of an electric vehicle, characterized in that: The following steps are involved: Step 1: Develop a rollover risk assessment and control strategy selection method. By calculating key parameters such as the vehicle's yaw rate and lateral acceleration in real time, the rollover risk of the vehicle is assessed and a rollover risk index model is established. Based on this model, the vehicle's center of gravity, driving speed, and steering angle are combined to determine whether the vehicle is close to a critical rollover state and determine the critical rollover threshold. Step 2: Based on the rollover risk index model and rollover threshold in Step 1, a multi-domain collaborative anti-rollover control model is established. Through the coordinated scheduling of independent steering, hub motor differential steering, and ESP braking control systems, active intervention in rollover risks is achieved. Specifically, the four-wheel independent steering system adjusts the front and rear wheel steering angles to provide additional lateral force to balance the vehicle body, and the hub motor differential steering system changes the vehicle's yaw moment to help the vehicle regain stability. At the same time, the ESP system adjusts the braking force of each wheel to further optimize the yaw characteristics. Step 3: Based on the multi-domain collaborative anti-rollover control model in Step 2, the central control unit dynamically assigns control priorities to each subsystem. The central control unit sets priorities and dynamically adjusts the four-wheel independent steering system, the in-wheel motor differential steering system, and the ESP system by real-time monitoring and calculating the rollover risk index. Step 4: Based on the dynamic priority allocation and control strategy execution results in step 3, the central control unit uses fuzzy logic control algorithms to coordinate the complex interactions between subsystems to ensure the coordination and consistency of systems such as four-wheel independent steering and hub motor differential steering under different working conditions; at the same time, through adaptive control algorithms, the control parameters of each subsystem are dynamically adjusted according to the real-time status and historical data of the vehicle, ultimately achieving precise control of multi-domain collaborative anti-rollover and improved fault tolerance capabilities.

2. The multi-domain coordinated rollover prevention control method for a wire-controlled chassis of an electric vehicle according to claim 1, characterized in that: The step 1 specifically includes: 11) Based on the vehicle's speed V and turning radius R, the vehicle's lateral acceleration ay is calculated for real-time assessment of rollover risk, as shown in the formula: 12) Based on the lateral acceleration ay and the vehicle's yaw rate ωz in 11), combined with the vehicle's center of gravity height hc, the rollover risk index RRI is calculated as shown in the formula, where α is the lateral acceleration coefficient and β is the yaw rate coefficient: 13) Based on the RRI calculated in 12) and the vehicle's center of gravity height h c , vehicle width w, driving speed V, calculate the rollover critical threshold λ RRI , as shown in the formula, where k1 is the speed correlation coefficient:

3. The multi-domain coordinated rollover prevention control method for a wire-controlled chassis of an electric vehicle according to claim 2, characterized in that: The second step specifically includes: 21) Based on the rollover risk index (RRI) in step 1, the steering angles of the front and rear wheels are adjusted through the four-wheel independent steering system, as shown in the formula: d fl =δ0+k fl ·RRI d fr =δ0+k fr ·RRI d rl =δ0-k rl ·RRI d rr =δ0-k rr ·RRI Among them, δ0 is the current wheel steering angle, k fl is the left front wheel cornering stiffness, k fr is the cornering stiffness of the right front wheel, k rl is the cornering stiffness of the left rear wheel, k rr is the cornering stiffness of the right rear wheel; 22) Based on the steering angle in 21), the wheel hub motor differential system is used to adjust the vehicle's yaw moment M by the torque difference ΔT. z , as shown in the formula, where k d is the controller gain parameter: 23) Based on the yaw moment M in 22) z and yaw rate ω z , the ESP system adjusts the braking force F of each wheel bi , as shown in the formula: Among them, Δω z is the change in yaw angular velocity, ω zmax is the maximum yaw angular velocity, F z is the total vertical force of the vehicle, μ i is the braking force assist coefficient.

4. The multi-domain coordinated rollover prevention control method for a wire-controlled chassis of an electric vehicle according to claim 3 is characterized in that: The step three specifically includes: 31) Based on the RRI value in step 2 and the importance of each subsystem, calculate the priority P of each subsystem i , as shown in the formula, where w i is the priority weight: ............. 32) Based on the priority P in 31) i , dynamically adjust the control frequency f of each subsystem i , as shown in the formula, where f base is the subsystem fundamental frequency, k p is the priority coefficient: f i =f base +k p ·P i 33) Based on the control frequency f in 32) i ,The central control unit sets the execution order according to the priority to ensure a fast response of high-priority systems.

5. The multi-domain coordinated rollover prevention control method for a wire-controlled chassis of an electric vehicle according to claim 4 is characterized in that: The step 4 specifically includes: 41) Based on the priority P in step 3 i , the fuzzy logic control algorithm is used to adjust the output of each subsystem to coordinate the overall stability of the vehicle. The fuzzy control output is shown as follows: 42) Based on the fuzzy control output in 41), the adaptive control algorithm is used to adjust the control parameters θ of each subsystem in real time. i , as shown in the formula, where γ is the RRI coefficient: 43) Based on the adaptive control algorithm in 42), the control strategy is optimized by combining historical data with real-time data to improve the fault tolerance and adaptability of the system.

6. The multi-domain coordinated rollover prevention control method for a wire-controlled chassis of an electric vehicle according to claim 1, characterized in that: A multi-domain collaborative anti-rollover control method for a wire-controlled chassis of an electric vehicle is applied to the wire-controlled chassis of an electric vehicle, comprising: an independent steering system (4), a hub motor differential steering system (5), an ESP braking stability control system (6), a chassis anti-rollover domain controller (7), and a power supply unit; The independent steering system comprises a steering motor (401), a steering motor controller (405), a two-stage worm gear reduction mechanism (402), a one-stage planetary gear reduction mechanism (411), a steering kingpin column (403), a rotation angle sensor (406), a wheel (404), a steering knuckle (410), a vehicle frame (408), a bearing (409), and a chassis rollover prevention domain controller (407). The output shaft of the steering motor (401) is connected to the input end of the one-stage planetary gear reduction mechanism (411), the one-stage planetary gear reduction mechanism (411) is gear-connected to the two-stage worm gear reduction mechanism (402), and the two-stage worm gear reduction mechanism (402) is connected to the steering kingpin column (403). Ensure that the output torque of the steering motor (401) is transmitted to the steering kingpin column (403) through the worm, so as to achieve precise control of the steering of the wheel (404); the upper end of the steering kingpin column (403) is connected to the vehicle frame (408) through the bearing (409), and the lower end is connected to the steering knuckle (410) of the wheel (404), and the steering knuckle (410) is fixedly connected to the wheel (404); the angle sensor (406) is installed at an appropriate position of the steering mechanical structure, and is used to monitor the angle of the steering kingpin column (403) in real time, and feed the data back to the steering motor controller (405), and the steering motor controller (405) transmits the data to the chassis anti-rollover domain controller (407) to achieve closed-loop control; The wheel hub motor differential steering system (5) comprises a wheel hub motor (501), a brake disc (502), a gear set primary reduction mechanism (504), a ball screw secondary reduction mechanism (503), a brake motor (505), a lower fork arm (506), a column (507), a steering arm (508), an upper fork arm (509), a shock absorber (510), and a vehicle frame mounting point (511); the wheel hub motor (501) is directly mechanically connected to the wheel (404), and by controlling the rotation speed of each wheel hub motor (501), a differential speed between different wheels (404) is achieved, thereby achieving a differential steering effect; the brake motor (505) is mechanically connected to the gear set primary reduction mechanism (504), the ball screw secondary reduction mechanism (503) is mechanically connected to the gear set primary reduction mechanism (504), and the ball screw secondary reduction mechanism (503) is fixedly connected to the brake disc (502) to achieve braking; The ESP braking stability control system (6) includes a brake motor (601), a ball screw reduction mechanism (602), a sensor (603), a wheel hub motor (604), a brake disc assembly (605), a mechanical electronic force amplification mechanism (606), a multi-stage gear reduction mechanism (607), a brake controller (612), a brake pedal position sensor (608), a brake pedal (609), an accelerator pedal (610), an accelerator pedal position sensor (611), and a chassis anti-rollover domain controller (613); the brake motor (6 01) is fixedly connected to a ball screw reduction mechanism (602), the ball screw reduction mechanism (602) is fixedly connected to a mechanical electronic force amplification mechanism (606), the mechanical electronic force amplification mechanism (606) is mechanically gear-connected to a multi-stage gear reduction mechanism (607), the multi-stage gear reduction mechanism (607) is mechanically gear-connected to a brake disc assembly (605) to provide braking force, the hub motor (604) is mechanically embedded in a wheel (404), and the sensor (603) is mounted on the wheel assembly for measuring wheel speed; The chassis anti-rollover domain controller (7) comprises a yaw angle sensor (701), a roll angle sensor (702), a central control unit (703) and a rollover suppression actuator; the yaw angle sensor (701) and the roll angle sensor (702) are arranged in the vehicle, monitor the yaw angular velocity and roll angle of the vehicle in real time, and transmit the data to the central control unit (703); the central control unit (703) analyzes the vehicle's motion state based on the data provided by the sensors, determines whether there is a rollover risk, and calculates a corresponding rollover suppression strategy; The power supply unit comprises a power battery pack (1), a DC-DC converter (2), an energy management system (3) and a cable network; the power battery pack (1) provides the main power supply for the entire wire-controlled chassis system, and converts high voltage electricity into low voltage electricity suitable for use by each subsystem through the DC-DC converter (2); the energy management system (3) is responsible for monitoring and managing the charge and discharge status of the battery, ensuring stable operation of the power supply unit, and distributing electric energy to each subsystem through the cable network; the cable network connects the power supply unit with the independent steering system (4), the hub motor differential steering system (5), the ESP braking stability control system (6) and the chassis anti-rollover domain controller (7), ensuring that each system obtains a stable power supply.

7. The multi-domain coordinated rollover prevention control method for a wire-controlled chassis of an electric vehicle according to claim 6, characterized in that: The column (507) is mechanically connected to the brake motor (505); the upper section of the column (507) is mechanically connected to the upper fork arm (509), and the lower end is mechanically connected to the lower fork arm (506); the lower end of the steering arm (508) is mechanically connected to the upper fork arm (509) and the lower fork arm (506), and the upper section of the steering arm (508) is mechanically connected to the secondary worm gear reduction mechanism (402); the lower end of the shock absorber (510) is mechanically connected to the column (507), and the upper section is mechanically connected to the steering arm (508). The steering motor (401) and the steering motor controller (405) are an integral casting. The steering motor (401) is mechanically connected to a first-stage planetary gear reduction mechanism (411), and the first-stage planetary gear reduction mechanism (411) is mechanically connected to a second-stage worm gear reduction mechanism (402). The upper end of the second-stage worm gear reduction mechanism (402) is mechanically connected to a vehicle frame mounting point (511). The steering motor controller (405) is connected to a chassis anti-rollover domain controller (407) via a CAN bus.

8. The multi-domain coordinated rollover prevention control method for a wire-controlled chassis of an electric vehicle according to claim 6, characterized in that: The brake pedal position sensor (608) and the accelerator pedal position sensor (611) are mechanically installed on the brake pedal (609) and the accelerator pedal (610). The brake pedal position sensor (608), the accelerator pedal position sensor (611) and the brake controller (612) are connected via a CAN bus. The brake controller (612) and the mechanical electronic force-enhancing mechanism (606) are connected via a CAN bus to control the braking force by sending and receiving signals. The brake controller (612) and the chassis anti-rollover domain controller (613) are connected via a CAN bus to receive control signals. The wheel speed sensor is connected to the chassis anti-rollover domain controller (613) via a CAN bus to receive signals.

9. The multi-domain coordinated rollover prevention control method for a wire-controlled chassis of an electric vehicle according to claim 6, characterized in that: The rollover suppression actuator comprises an electronic stabilizer bar (705), a hydraulic rollover suppressor (706) and a control circuit (704). The control signal generated by the central control unit (703) drives the electronic stabilizer bar (705) and the hydraulic rollover suppressor (706) to operate through the control circuit (704), thereby adjusting the vehicle's suspension system and lateral support force to suppress the vehicle's rollover tendency.

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