Multi-domain cooperative anti-rollover control method for drive-by-wire chassis of electric carrying equipment

Abstract

The invention discloses an electric carrying equipment drive-by-wire chassis multi-domain collaborative anti-rollover control method, which comprises the following steps of: 1, constructing a rollover risk assessment and control strategy selection method, and calculating key parameters such as yaw velocity and lateral acceleration of a vehicle in real time; step 2, based on the rollover risk index model and the rollover critical threshold in the step 1, establishing a multi-domain collaborative rollover prevention control model, and performing collaborative scheduling on independent steering, hub motor differential steering and an ESP brake control system; step 3, based on the multi-domain collaborative anti-rollover control model in the step 2; and 4, based on the priority dynamic allocation and control strategy execution result in the step 3, the central control unit coordinates the complex interaction relationship among the subsystems by using a fuzzy logic control algorithm. The invention provides a reliable control strategy priority and use frequency method, and provides a more reliable anti-rollover solution for the electric carrying equipment under a complex dynamic working condition.

Description

Technical Field

[0001] The present invention relates to the technical field of control of a by-wire chassis of an electric vehicle, and in particular to a multi-domain collaborative anti-rollover control method for a by-wire chassis of an electric vehicle. Background Art

[0002] With the development of electric vehicles, chassis-by-wire technology has gradually been applied in vehicle stability control, especially in the field of electric vehicles and unmanned driving. Due to its flexible handling and high-precision control capabilities, chassis-by-wire has become an important technical means to improve vehicle safety. However, in actual driving, the risk of vehicle rollover still exists, especially in high-speed turns, emergency obstacle avoidance or bad road conditions, when the lateral force of the vehicle is too large, it is easy to cause a rollover accident. Traditional anti-rollover systems, such as the electronic stability program (ESP), mainly rely on braking force adjustment to prevent rollover, but this single control method often performs insufficiently in the face of complex dynamic conditions and cannot effectively deal with a variety of unstable factors.

[0003] In recent years, new technologies such as four-wheel independent steering and hub motor differential steering have been introduced into electric vehicles, which have brought new opportunities for rollover prevention control. Among the existing rollover prevention control methods, most rollover prevention strategies rely on only a single control technology, such as electronic stability program (ESP), active suspension system or differential braking, but fail to fully integrate the advantages of multiple control technologies. This single technology-dependent method often fails to achieve the best control effect when dealing with changing road conditions or emergencies, and it is difficult to meet the vehicle's comprehensive dynamic performance requirements under extreme working conditions. Although a few studies have attempted to use multiple control technologies for rollover prevention control, these studies often lack detailed discussions and optimizations on the priority and frequency of use of different technical means in practical applications. Therefore, in order to improve the overall effectiveness and adaptability of the rollover prevention system, there is an urgent need for a rollover prevention control method that can work collaboratively in multiple domains to achieve precise control of the vehicle's lateral force and yaw moment, and to clarify the synergy, priority ranking and dynamic adjustment mechanism of various control technologies in the comprehensive rollover prevention strategy, so as to improve the stability and safety of the vehicle under complex working conditions.

[0004] There have been many breakthroughs in the existing chassis anti-rollover control method research. For example, the Chinese invention patent application number is CN201611254300.8, entitled "A four-wheel steering vehicle anti-rollover system and control method thereof", which proposes a method of anti-rollover control through a front wheel differential braking module and maintaining the driver's original driving intention through a rear wheel steering module, avoiding the secondary accident that may be caused by not considering the driving intention during traditional anti-rollover control, enhancing the robustness of the system and minimizing the controller output; the Chinese invention patent application number is CN201811557669.5, entitled "A vehicle anti-rollover method based on model predictive control", which compares the lateral load transfer rate with a preset lateral load transfer rate threshold, and adjusts the front wheel steering angle of the vehicle according to the comparison result of the two, and controls the braking force of the four wheels to achieve anti-rollover control; the Chinese invention patent application number is C N202011030509.2, named "Comprehensive anti-rollover control method for distributed drive electric vehicles", this method uses four control strategies, namely yaw stability control, roll stability control, decoupling control torque distribution strategy and anti-rollover control based on differential braking, to jointly control the vehicle driving force and braking force, thereby achieving comprehensive anti-rollover control for distributed drive electric vehicles; the Chinese invention patent application number is CN201610552073.0, named "A four-wheel steering vehicle anti-rollover control system integrating vehicle speed changes", this method adds a working condition discrimination unit, adopts a rarely used control mode, and discriminates the working condition according to parameters such as vehicle speed, wheel angle, and roll angular velocity, and adjusts the vehicle's driving state through differential braking and four-wheel steering actuators, thereby changing the vehicle's state to achieve the effect of suppressing rollover.

[0005] However, the above-mentioned anti-rollover control methods have the following two potential problems:

[0006] 1. Limitations of a single control domain: Although existing technologies such as Chinese invention patent application number CN201611254300.8: "A four-wheel steering vehicle anti-rollover system and control method thereof" and Chinese invention patent application number CN201811557669.5: "A vehicle anti-rollover method based on model predictive control" enhance 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 a braking system or a steering system. This method that relies on a single control domain may not be able to provide comprehensive stability support when faced with complex dynamic conditions or changing road conditions. In addition, a single control method 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, thereby limiting the improvement of the overall anti-rollover performance.

[0007] 2. Lack of optimization of dynamic priority and frequency of use: Existing technologies such as Chinese invention patent application number CN202011030509.2: "Anti-rollover integrated control method for distributed drive electric vehicles" and Chinese invention patent application number CN201610552073.0: "A four-wheel steering vehicle anti-rollover control system integrating vehicle speed changes" propose the integrated use of multiple control strategies, but these methods often lack a dynamic adjustment mechanism for the priority and frequency of use between different control strategies. In actual driving, the vehicle may face a variety of emergency situations, requiring the system to dynamically adjust the application of control strategies according to the real-time vehicle status and external environment to ensure the best anti-rollover effect under various working conditions. The lack of this dynamic adjustment capability may lead to a waste of control resources or the inability to provide effective control at critical moments. Summary of the invention

[0008] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot 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 of the wire-controlled 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 a wire-controlled chassis of an electric vehicle, which integrates four-wheel independent steering, hub motor differential steering and ESP system to propose a strategy for comprehensive regulation of vehicle lateral force and yaw moment, aiming to improve the vehicle's driving stability and safety under high-speed cornering, 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 control strategy priority and usage frequency method, providing a more reliable anti-rollover solution for electric vehicles under complex dynamic conditions.

[0011] In order to solve the above technical problems, the present invention provides the following technical solutions: a multi-domain coordinated rollover prevention control method for a wire-controlled chassis of an electric vehicle, comprising the following steps:

[0012] Step 1: Construct a rollover risk assessment and control strategy selection method. By calculating the vehicle's yaw angular velocity, lateral acceleration and other key parameters in real time, the rollover risk of the vehicle is assessed and a rollover risk index model is established. Based on this model, combined with the vehicle's center of gravity position, driving speed and steering angle factors, it is determined whether the vehicle is close to the critical state of rollover and the critical rollover threshold is obtained.

[0013] Step 2: Based on the rollover risk index model and rollover critical threshold in step 1, a multi-domain collaborative anti-rollover control model is established to achieve active intervention in rollover risk through the coordinated scheduling of independent steering, hub motor differential steering and ESP braking control system; specifically, the front and rear wheel steering angles are adjusted through the four-wheel independent steering system to provide additional lateral force to balance the vehicle body, and the vehicle yaw moment is changed through the hub motor differential steering system to help the vehicle restore stability. At the same time, the ESP system adjusts the braking force of each wheel 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 priority of each subsystem; the central control unit sets the priority and dynamically adjusts the four-wheel independent steering system, the hub motor differential steering system, and the ESP system by real-time monitoring and calculating the rollover risk index;

[0015] 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 rollover prevention and improved fault tolerance capabilities.

[0016] As a preferred solution of the multi-domain coordinated rollover prevention control method for the wire-controlled chassis of an electric vehicle according to the present invention, the step 1 specifically includes:

[0017] 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:

[0018]

[0019] 12) Based on the lateral acceleration ay and the yaw rate ωz of the vehicle in 11), combined with the height of the center of gravity of the vehicle 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:

[0020]

[0021] 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:

[0022]

[0023] As a preferred solution of the multi-domain coordinated rollover prevention control method for the wire-controlled chassis of the electric vehicle equipment of the present invention, the step 2 specifically includes:

[0024] 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:

[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] Among them, δ0 is the current wheel steering angle, k fl is the cornering stiffness of the left front wheel, k fr is the right front wheel cornering stiffness, 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 angle in 21), the wheel hub motor differential system is used to adjust the vehicle's yaw moment M through the torque difference ΔT z , as shown in the formula, where k d is the controller gain parameter:

[0031]

[0032] 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:

[0033]

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

[0035] As a preferred solution of the multi-domain coordinated rollover prevention control method for the wire-controlled chassis of the electric vehicle equipment of the present invention, the step three specifically includes:

[0036] 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:

[0037]

[0038] .............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:

[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 a fast response of the high priority system.

[0041] As a preferred solution of the multi-domain collaborative rollover prevention control method for the wire-controlled chassis of the electric vehicle equipment of the present invention, the step 4 specifically includes:

[0042] 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 in the formula:

[0043]

[0044] 42) Based on the fuzzy control output in 41), the control parameters θ of each subsystem are adjusted in real time using an adaptive control algorithm i , as shown in the formula, where γ is the RRI coefficient:

[0045]

[0046] 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.

[0047] As a preferred solution of the multi-domain collaborative anti-rollover control method for the wire-controlled chassis of electric vehicle equipment of the present invention, the multi-domain collaborative anti-rollover control method for the wire-controlled chassis of electric vehicle equipment is applied to the wire-controlled chassis of electric vehicle 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 gear reduction mechanism, a primary planetary gear reduction mechanism, a steering kingpin column, an angle sensor, a wheel, a steering knuckle, a frame, a bearing, and a chassis rollover protection 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 gear reduction mechanism, and the secondary worm gear reduction mechanism is connected to the steering kingpin column to ensure that the output torque of the steering motor is transmitted to the steering kingpin column through the worm, so as to achieve precise control of wheel steering; the upper end of the steering kingpin column is connected to the frame through a bearing, and the lower end is connected to the steering knuckle of the wheel, and the steering knuckle is mechanically connected to the wheel; the angle sensor is installed at an appropriate position of the steering mechanical structure, and is used to monitor the steering kingpin column angle in real time, and feed back the data to the steering motor controller, and the steering motor controller transmits the data to the chassis rollover protection domain controller to achieve closed-loop control;

[0049] The wheel hub motor differential steering system includes a wheel hub motor, a brake disc, a primary reduction mechanism of a gear set, a secondary reduction mechanism of a ball screw, 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 wheel hub motor is directly mechanically connected to the wheel, and the speed difference between different wheels is achieved by controlling the rotation speed of each wheel hub motor, thereby achieving the effect of differential steering; the brake motor is mechanically connected to the primary reduction mechanism of the gear set, the secondary reduction mechanism of the ball screw is mechanically connected to the primary reduction mechanism of the gear set, and the secondary reduction mechanism of the ball screw 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, a sensor, a wheel hub motor, a brake disc assembly, a mechanical electronic force amplification 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 rollover protection 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 electronic force amplification mechanism, the mechanical electronic force amplification 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 wheel hub motor is mechanically embedded in the wheel, and the sensor is installed on the wheel assembly for measuring the wheel speed;

[0051] The chassis rollover prevention domain controller includes a yaw angle sensor, a roll angle sensor, a central control unit and a rollover suppression actuator; the yaw angle sensor and the roll angle sensor 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; the central control unit analyzes the vehicle's motion state based on the data provided by the sensor, 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 supply for the entire wire-controlled chassis system, and converts high voltage electricity into low voltage electricity suitable for each subsystem through a DC-DC converter; the energy management system is responsible for monitoring and managing the charging and discharging status of the battery, ensuring the stable operation of the power supply unit, and distributing electrical energy to each subsystem through a 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 protection domain controller to ensure that each system has a stable power supply.

[0053] As a preferred solution of the multi-domain collaborative anti-rollover control method for the wire-controlled chassis of an electric vehicle equipment described in the present invention, wherein: the column is mechanically connected to the brake motor, the upper section of the column is mechanically connected to the upper fork arm, and the lower end 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 section of the steering arm is mechanically connected to the secondary worm gear reduction mechanism; the lower end of the shock absorber is mechanically connected to the column, and the upper section is mechanically connected to the steering arm; the steering motor and the steering motor controller are an integral casting, 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 gear reduction mechanism; the upper end of the secondary worm gear reduction mechanism is mechanically connected to the frame mounting point; the steering motor controller is connected to the chassis anti-rollover domain controller CAN bus.

[0054] As a preferred solution of the multi-domain collaborative anti-rollover control method for the wire-controlled chassis of the electric vehicle equipment described in the present invention, wherein: 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 a CAN bus, the brake controller is connected to the mechanical electronic force amplification mechanism through a CAN bus to control the braking force by sending and receiving signals, the brake controller is connected to the chassis anti-rollover domain controller through a CAN bus to receive control signals, and the wheel speed sensor is connected to the chassis anti-rollover domain controller through a CAN bus to receive signals.

[0055] As a preferred scheme of the multi-domain collaborative anti-rollover control method of the wire-controlled chassis of the electric transport equipment described in the present invention, 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, adjusts the vehicle's suspension system and lateral support force, so as to suppress the vehicle's rollover tendency.

[0056] Beneficial effects 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. The evaluation model can dynamically reflect the rollover risk of the vehicle under different working conditions, so that the system can quickly sense and respond to changes in the vehicle's state.

[0058] 2. By calculating the critical rollover threshold, it is possible to predict in advance the state of the vehicle approaching rollover and give a warning signal. This makes the anti-rollover control forward-looking and can take effective stabilization measures in advance to reduce the possibility of accidents.

[0059] 3. The present invention combines four-wheel independent steering, hub motor differential control and 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 work of these subsystems, the stability of the vehicle is significantly improved, especially in extreme working conditions, which can effectively prevent the vehicle from losing control or rolling over.

[0060] 4. Through the priority dynamic allocation model, the execution order and frequency of control instructions can be adjusted in real time according to the contribution of each subsystem to vehicle stability. This mechanism ensures that when the risk of rollover is high, the most critical subsystem is responded to first, optimizes the allocation of control resources, and enhances the safety and response speed of the vehicle.

[0061] 5. The present invention introduces fuzzy logic control and adaptive control algorithms, and can flexibly respond to different vehicle operating conditions through dynamic adjustment of fuzzy control rules. At the same time, the adaptive control algorithm automatically optimizes the control parameters of each subsystem by learning historical data and real-time status, thereby enhancing the self-learning ability of the system and improving the anti-rollover ability and adaptability of the vehicle.

[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 risk of rollover caused by changes in vehicle status or environmental changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

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

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

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

[0067] Figure 4 This is a schematic diagram of the hub motor differential steering system proposed by the present invention;

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

[0069] Figure 6 This is a diagram of the chassis rollover protection domain controller architecture proposed in the present invention. DETAILED DESCRIPTION

[0070] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

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

[0072] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0073] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0074] Reference Figure 1-Figure 6 , provides a multi-domain coordinated anti-rollover control method for a wire-controlled chassis of an electric vehicle, comprising the following steps:

[0075] Step 1: Construct a rollover risk assessment and control strategy selection method. By calculating the vehicle's yaw angular velocity, lateral acceleration and other key parameters in real time, the rollover risk of the vehicle is assessed and a rollover risk index model is established. Based on this model, combined with the vehicle's center of gravity position, driving speed and steering angle factors, it is determined whether the vehicle is close to the critical state of rollover and the critical rollover threshold is obtained.

[0076] Step 2: Based on the rollover risk index model and rollover critical threshold in step 1, a multi-domain collaborative anti-rollover control model is established to achieve active intervention in rollover risk through the coordinated scheduling of independent steering, hub motor differential steering and ESP braking control system; specifically, the front and rear wheel steering angles are adjusted through the four-wheel independent steering system to provide additional lateral force to balance the vehicle body, and the vehicle yaw moment is changed through the hub motor differential steering system to help the vehicle restore 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 anti-rollover control model in step 2, the central control unit dynamically allocates the control priority of each subsystem; the central control unit sets the priority and dynamically adjusts the four-wheel independent steering system, the hub motor differential steering system, and the ESP system by real-time monitoring and calculating the rollover risk index;

[0078] 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 rollover prevention and improved fault tolerance capabilities.

[0079] Among them, step one specifically includes:

[0080] 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:

[0081]

[0082] 12) Based on the lateral acceleration ay and the yaw rate ωz of the vehicle in 11), combined with the height of the center of gravity of the vehicle 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:

[0083]

[0084] 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:

[0085]

[0086] Furthermore, step 2 specifically includes:

[0087] 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:

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

[0093] 22) Based on the steering angle in 21), the wheel hub motor differential system is used to adjust the vehicle's yaw moment M 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 yaw rate ω z , the ESP system adjusts the braking force F of each wheel bi , as shown in the formula:

[0096]

[0097] Among them, 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 assistance coefficient.

[0098] Furthermore, step three specifically includes:

[0099] 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:

[0100]

[0101] .............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:

[0102] f i =f base +k p ·P i

[0103] 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 the high priority system.

[0104] Among them, step four specifically includes:

[0105] 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 in the formula:

[0106]

[0107] 42) Based on the fuzzy control output in 41), the control parameters θ of each subsystem are adjusted in real time using an adaptive control algorithm i , as shown in the formula, where γ is the RRI coefficient:

[0108]

[0109] 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.

[0110] Specifically, the multi-domain collaborative anti-rollover control method of the electric vehicle control-by-wire chassis is applied to the electric vehicle control-by-wire chassis, including: 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] The independent steering system includes a steering motor 401, a steering motor controller 405, a secondary worm gear reduction mechanism 402, a primary planetary gear reduction mechanism 411, a steering kingpin column 403, a rotation angle sensor 406, a wheel 404, a steering knuckle 410, a frame 408, a bearing 409, and a chassis rollover protection 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 connected to the mechanical gear of the secondary worm gear reduction mechanism 402, and the secondary 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 realize precise control of the steering of the wheel 404; the upper end of the steering kingpin column 403 is connected to the 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 back the data to the steering motor controller 405, and the steering motor controller 405 transmits the data to the chassis rollover protection domain controller 407 to realize closed-loop control;

[0112] The wheel hub motor differential steering system 5 includes 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 frame mounting point 511; the wheel hub motor 501 is directly mechanically connected to the wheel 404, and the speed difference between different wheels 404 is achieved by controlling the rotation speed of each wheel hub motor 501, thereby achieving the effect of differential steering; 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; further, the column 507 is connected to the brake The driving motor 505 is fixedly connected, 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 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 an integral casting, 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 gear reduction mechanism 402; the upper end of the secondary worm gear reduction mechanism 402 is fixedly connected to the frame mounting point 511; the steering motor controller 405 is connected to the chassis rollover protection domain controller 407 CAN bus.

[0113] Among them, 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 rollover protection domain controller 613; the brake motor 601 is mechanically connected to the ball screw reduction mechanism 602, the ball screw reduction mechanism 602 is fixedly connected to the mechanical electronic force amplification mechanism 606, the mechanical electronic force amplification mechanism 606 is mechanically connected to the multi-stage gear reduction mechanism 607, and the multi-stage gear reduction mechanism 607 is connected to the brake disc assembly 605 through mechanical gears. 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 via the CAN bus, the brake controller 612 and the mechanical electronic force amplification mechanism 606 are connected via the 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 the CAN bus to receive control signals, and the wheel speed sensor is connected to the chassis anti-rollover domain controller 613 via 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 supply for the entire wire-controlled chassis system, and converts high voltage electricity 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 charging and discharging status of the battery, ensuring the stable operation of the power supply unit, and distributing electrical 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 rollover protection domain controller 7 to ensure that each system has a stable power supply.

[0115] The chassis rollover prevention domain controller 7 includes 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 to 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 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;

[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 through the control circuit 704, adjusts the vehicle's suspension system and lateral support force, so as 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 rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A multi-domain collaborative rollover prevention control method for a wire-controlled chassis of an electric vehicle, characterized in that: The following steps are involved: Step 1: Construct a rollover risk assessment and control strategy selection method. By calculating the vehicle's yaw angular velocity, lateral acceleration and other key parameters in real time, the rollover risk of the vehicle is assessed and a rollover risk index model is established. Based on this model, combined with the vehicle's center of gravity position, driving speed and steering angle factors, it is determined whether the vehicle is close to the critical state of rollover and the critical rollover threshold is obtained. Step 2: Based on the rollover risk index model and rollover critical threshold in step 1, a multi-domain collaborative anti-rollover control model is established to achieve active intervention in rollover risk through the coordinated scheduling of independent steering, hub motor differential steering and ESP braking control system; specifically, the front and rear wheel steering angles are adjusted through the four-wheel independent steering system to provide additional lateral force to balance the vehicle body, and the vehicle yaw moment is changed through the hub motor differential steering system to help the vehicle restore 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 allocates the control priority of each subsystem; the central control unit sets the priority and dynamically adjusts the four-wheel independent steering system, the hub 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 rollover prevention 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 is 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 yaw rate ωz of the vehicle in 11), combined with the height of the center of gravity of the vehicle 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 is characterized in that: The step 2 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 cornering stiffness of the left front wheel, k fr is the right front wheel cornering stiffness, 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 through 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 assistance 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 the high priority system.

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 in the formula: 42) Based on the fuzzy control output in 41), the control parameters θ of each subsystem are adjusted in real time using an adaptive control algorithm 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: The multi-domain coordinated rollover prevention 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 wheel hub motor differential steering system (5), an ESP braking stability control system (6), a chassis rollover prevention domain controller (7) and a power supply unit; The independent steering system comprises a steering motor (401), a steering motor controller (405), a secondary worm gear reduction mechanism (402), a primary 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 primary planetary gear reduction mechanism (411), the primary planetary gear reduction mechanism (411) is gear-connected to the secondary worm gear reduction mechanism (402), and the secondary 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 gear, so as to realize accurate control of the steering of the wheel (404); the upper end of the steering kingpin column (403) is connected to the 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 steering angle sensor (406) is installed at an appropriate position of the steering mechanical structure, and is used to monitor the steering angle of the steering kingpin column (403) in real time, and feed back the data to the steering motor controller (405), and the steering motor controller (405) transmits the data to the chassis rollover protection domain controller (407) to realize 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 frame mounting point (511); the wheel hub motor (501) is directly mechanically connected to the wheel (404), and the speed difference between different wheels (404) is achieved by controlling the rotation speed of each wheel hub motor (501), thereby achieving the effect of differential steering; 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) comprises 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 rollover prevention 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 connected to a multi-stage gear reduction mechanism (607), the multi-stage gear reduction mechanism (607) is connected to a brake disc assembly (605) through a mechanical gear to provide braking force, the wheel 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; 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 movement state of the vehicle 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 charging and discharging state 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 an independent steering system (4), a wheel hub motor differential steering system (5), an ESP braking stability control system (6) and a chassis rollover protection 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 is 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 primary planetary gear reduction mechanism (411); the primary planetary gear reduction mechanism (411) is mechanically connected to a secondary worm gear reduction mechanism (402); the upper end of the secondary worm gear reduction mechanism (402) is mechanically connected to a frame mounting point (511); the steering motor controller (405) is connected to a chassis rollover protection 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 is 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 so as 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 so as to receive control signals; and the wheel speed sensor is connected via a CAN bus to the chassis anti-rollover domain controller (613) so as 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 work through the control circuit (704), thereby adjusting the suspension system and lateral support force of the vehicle to suppress the rollover tendency of the vehicle.

Images