A magnetorheological-pneumatic coordinated braking system, control method and automobile

Abstract

This invention proposes a magnetorheological-pneumatic coordinated braking system, control method, and vehicle, belonging to the field of vehicle engineering. The system includes: a brake pedal for generating a braking request signal; an electronic control unit (ECU) electrically connected to the brake pedal, receiving the braking request signal and vehicle status signals and sending control commands; a magnetorheological braking unit electrically connected to the ECU for generating braking force; a pneumatic eddy current braking unit electrically connected to the ECU, creating controllable turbulence behind the wheel hub to generate reverse aerodynamic drag; and an energy recovery unit connected to the ECU and the vehicle's drive motor, which, upon receiving commands from the ECU, converts the vehicle's kinetic energy into electrical energy for recovery and generates regenerative braking force. This invention, through the integration and synergy of magnetorheological, pneumatic, and energy recovery technologies, solves the technical problems of slow response, low control precision, single energy recovery method, and poor environmental adaptability in existing braking systems, thereby improving the braking safety and reliability of vehicles.

Description

Technical Field

[0001] This invention belongs to the field of vehicle engineering technology, and in particular relates to a magnetorheological-pneumatic coordinated braking system, control method, and automobile. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] The vehicle braking system is a core component for vehicle driving safety. Traditional hydraulic friction braking systems have revealed many shortcomings in application and are no longer suitable for the performance requirements of modern vehicles, especially autonomous driving.

[0004] Traditional automotive braking systems rely on hydraulic transmission of braking force. The physical displacement and fluid flow introduce significant delays, resulting in a response time exceeding 200ms, which cannot meet the ≤100ms braking response requirement of Level 4 autonomous driving. Furthermore, mechanical contact friction braking not only generates a large amount of dust, accounting for 16% of PM2.5 emissions, but also suffers from severe material wear and high maintenance costs. Its hydraulic oil is also greatly affected by temperature; its viscosity increases by 300% at -40℃, easily leading to brake failure. At high temperatures, it can also experience vapor lock and a decrease in boiling point, resulting in poor adaptability to extreme operating conditions.

[0005] Furthermore, traditional systems have low energy recovery rates, recovering only a small amount of kinetic energy, resulting in significant energy waste. The industry's single magnetorheological or pneumatic braking technologies also have limitations, such as magnetorheological fluid sedimentation and pneumatic braking being only applicable to high-speed conditions. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention provides a magnetorheological-pneumatic coordinated braking system, a control method, and an automobile, to solve the technical problems of slow response, low control accuracy, single energy recovery, and poor environmental adaptability of existing braking systems.

[0007] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions: The first aspect of this invention provides a magnetorheological-pneumatic coordinated braking system; A magnetorheological-pneumatic coordinated braking system includes: The brake pedal is used to generate a braking request signal; The electronic control unit (ECU) is electrically connected to the brake pedal and is used to receive the braking request signal and vehicle status signal, and generate and send control commands according to a preset strategy. The magnetorheological braking unit, electrically connected to the ECU, includes a brake disc, a cavity disposed within the brake disc, a magnetorheological fluid filled within the cavity, and an embedded electromagnetic field generator. Upon receiving a command from the ECU, the embedded electromagnetic field generator generates a controllable magnetic field, altering the rheological properties of the magnetorheological fluid to generate braking force. The pneumatic vortex braking unit is electrically connected to the ECU and includes a vortex plate and a drive mechanism. After receiving the command from the ECU, the drive mechanism drives the vortex plate to expand to the working position under preset conditions, creating controllable turbulence behind the wheel hub and generating reverse aerodynamic drag. The energy recovery unit is connected to the ECU and the vehicle's drive motor. After receiving instructions from the ECU, it converts the vehicle's kinetic energy into electrical energy for recovery and generates regenerative braking force.

[0008] As a further technical solution, the magnetorheological fluid includes magnetic particles, silicone oil carrier fluid, and dispersant; the magnetic particles are Fe3O4@SiO2 core-shell structured particles, with Fe3O4 as the core and SiO2 as the outer shell; the dispersant is a nanodiamond dispersant; As a further technical solution, the magnetic particles have a particle size of 150-250 nm; the magnetic particles are suspended in the silicone oil carrier liquid at a volume percentage of 35%-55%.

[0009] As a further technical solution, the embedded electromagnetic field generator includes multiple sets of electromagnetic coils arranged in an array, which are used to generate a gradient magnetic field under the control of the ECU to adjust the yield stress of the magnetorheological fluid.

[0010] As a further technical solution, the driving mechanism is a shape memory alloy hinge, and the vortex plate is made of carbon fiber composite material.

[0011] As a further technical solution, the surface of the vortex plate is coated with a polyetheretherketone coating, and the working position of the vortex plate after it is deployed forms an angle of 40°-50° with the plane where the hub is located.

[0012] As a further technical solution, temperature-controlled ceramic microcapsules are also added to the magnetorheological fluid to release activators at low temperatures to reduce viscosity.

[0013] A second aspect of the present invention provides a control method for a magnetorheological-pneumatic coordinated braking system.

[0014] A control method for a magnetorheological-pneumatic coordinated braking system includes: Step S1: Real-time acquisition of vehicle braking request signals and status parameters, wherein the status parameters include at least vehicle speed signals and brake pedal opening signals; Step S2: Based on the vehicle speed signal and the brake pedal opening signal, determine whether the current braking condition is a normal braking mode or an emergency braking mode. Step S3: When it is determined to be a normal braking mode, control the aerodynamic eddy current braking unit to remain in the retracted state, and coordinate the control of the magnetorheological braking unit and the energy recovery unit to perform braking according to the target braking force. When the emergency braking mode is detected, the magnetorheological braking unit, the aerodynamic eddy current braking unit, and the energy recovery unit are activated simultaneously, so that the three work together to generate braking force and achieve three-mode coordinated braking.

[0015] As a further technical solution, the pattern determination step specifically includes: The vehicle speed signal is compared with a first preset threshold, and the brake pedal opening signal is compared with a second preset threshold. When the vehicle speed is lower than the first preset threshold and the brake pedal opening is lower than the second preset threshold, it is determined to be in normal braking mode; When the vehicle speed is higher than or equal to the first preset threshold, or when the brake pedal opening is higher than or equal to the second preset threshold, it is determined to be an emergency braking mode.

[0016] A third aspect of the present invention provides an automobile comprising the magnetorheological-pneumatic coordinated braking system described in any of the preceding claims.

[0017] The above one or more technical solutions have the following beneficial effects: (1) This invention achieves a dual breakthrough in braking system response speed and control precision through intelligent coordinated control of the magnetorheological braking unit, the aerodynamic eddy current braking unit, and the energy recovery system, significantly improving vehicle driving safety. The magnetorheological braking unit is precisely controlled by current, with a full-chain response time of ≤0.05 seconds for current-magnetic field-particle chain formation-fluid solidification. Combined with the rapid deployment characteristic of the aerodynamic eddy current braking unit of 120ms, the total braking response time of the system across the entire range is ≤50ms, which is far superior to the traditional hydraulic braking system and meets the braking response requirements of L4 level autonomous driving, effectively shortening the braking distance during emergency braking. At the same time, the control method divides the braking conditions into three categories based on vehicle speed and brake pedal opening and dynamically distributes the braking force. In emergency conditions, the three braking forces are vector superimposed. Combined with the integrated control of ABS and ESC functions, the braking force distribution of each wheel is finely adjusted in real time, effectively preventing wheel lock-up, suppressing vehicle sideslip, maximizing the use of ground adhesion, and ensuring the braking stability of the vehicle under high speed and complex road conditions. In addition, for extreme temperature conditions, a special control strategy of low-temperature viscosity adjustment and high-temperature magnetic field adaptive compensation is adopted to ensure that the system performance degradation is less than 5%, achieve stable braking in all weather conditions, and completely solve the technical pain points of low-temperature failure and high-temperature air resistance in traditional braking systems.

[0018] (2) This control method solves the dust pollution problem of traditional braking systems, while achieving efficient multi-dimensional energy recovery, taking into account both environmental protection and energy saving. During the braking process, magnetorheological non-mechanical contact braking is given priority, and aerodynamic eddy current braking relies on aerodynamics to generate resistance. There is no friction and wear of brake pads throughout the process, which eliminates braking dust pollution and reduces wear and tear of braking components, thereby reducing system maintenance costs. In terms of energy utilization, the control method enables the energy recovery system and the braking unit to work in deep coordination. In addition to kinetic energy recovery under basic braking conditions, it can also comprehensively recover frictional heat energy and aerodynamic wind energy in high-speed and emergency braking conditions, breaking the limitation of traditional systems that only recover a small amount of kinetic energy. Moreover, aerodynamic eddy current braking is only activated in high-speed emergency conditions and is kept in a retracted state at other times to avoid additional wind resistance loss. Magnetorheological braking consumes only a small amount of control current, which significantly reduces the energy consumption of the whole vehicle compared with traditional hydraulic braking systems. It is especially suitable for new energy vehicles, effectively extending the vehicle's driving range and improving the energy utilization efficiency of the whole vehicle.

[0019] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0021] Figure 1 This is a flowchart of the method in the first embodiment.

[0022] Figure 2 This is a system structure diagram of the second embodiment. Detailed Implementation

[0023] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0025] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0026] The overall approach of this invention addresses the pain points of traditional braking systems, such as slow response, high pollution, poor climate adaptability, and low energy recovery rate. This invention uses an Electronic Control Unit (ECU) as its core, integrating magnetorheological, aerodynamic eddy current braking, and energy recovery technologies. It collects vehicle braking and driving signals through multiple sensors, processes them using algorithms to classify braking conditions, and achieves three-modal intelligent collaborative control. In the basic operating condition, magnetorheological braking is the primary method, with energy recovery working simultaneously. In high-speed emergency conditions, aerodynamic eddy current braking is superimposed. In extreme temperature conditions, a specific adaptation strategy ensures performance. Simultaneously, it integrates ABS / ESC functions to dynamically adjust braking force distribution, balancing extreme braking response, all-weather adaptability, zero dust pollution, and multi-dimensional energy recovery, significantly improving the safety, environmental friendliness, and energy efficiency of the braking system.

[0027] Example 1 This embodiment discloses a magnetorheological-pneumatic coordinated braking system; like Figure 1 As shown, a magnetorheological-pneumatic coordinated braking system comprises five core components: a brake pedal 101, an electronic control unit (ECU) 102, a magnetorheological braking unit 103, a pneumatic eddy current braking unit 104, and an energy recovery unit 105. The units are connected by electrical signals to realize real-time transmission of braking signals and intelligent coordinated control of braking force.

[0028] The brake pedal is the command input component for vehicle braking. A high-precision displacement sensor is mounted at its end. This sensor is electrically connected to the ECU. When the driver presses the brake pedal, the sensor converts the mechanical displacement signal of the pedal into a linear electrical signal in real time and quickly transmits the braking request signal to the electronic control unit (ECU). The strength of the electrical signal is positively correlated with the pedal depth and speed, accurately representing the driver's braking intention.

[0029] The Electronic Control Unit (ECU) is the control center of the entire braking system. It incorporates multivariate control algorithms such as Model Predictive Control (MPC), fuzzy logic, and adaptive control. It is electrically connected to the vehicle's wheel speed sensors, vehicle speed sensor, acceleration sensor, yaw rate sensor, and Battery Management System (BMS), synchronously receiving braking request signals, vehicle driving status signals, and battery status signals. The ECU possesses millisecond-level data fusion processing capabilities, analyzing and making decisions on multi-source signals according to preset strategies. It generates and sends precise control commands to the magnetorheological braking unit, aerodynamic eddy current braking unit, and energy recovery unit. It also integrates ABS anti-lock braking and ESC electronic stability control functions, adjusting power distribution in real time to ensure vehicle stability during braking.

[0030] In addition, the ECU's signal acquisition module performs filtering, amplification, analog-to-digital conversion, and signal fusion preprocessing on all received electrical signals. A Kalman filter algorithm is used to eliminate electromagnetic interference and vibration noise during signal transmission. Weak sensor signals are amplified to a standard voltage range of 0-5V via an amplification circuit. A 16-bit analog-to-digital converter converts the analog signals into digital signals. Finally, a signal fusion algorithm integrates the braking request signals from the dual sensors and multi-dimensional vehicle status signals, ensuring signal accuracy and reliability and providing a data foundation for subsequent condition judgment and braking decisions. The data processing module uses a built-in control algorithm to perform millisecond-level fusion analysis (≤10ms) on the preprocessed multi-source signals. Based on a preset control strategy, it calculates the target braking force and the braking force distribution ratio of each unit, and generates corresponding PWM pulse width modulation control commands. The command output module uses PWM technology to convert the control commands into current / voltage signals recognizable by each braking unit and sends them to the magnetorheological braking unit, aerodynamic eddy current braking unit, and energy recovery unit, achieving a control accuracy of 0.1A / 0.01V. The power supply module is for the ECU. It provides a stable on-board voltage (12V / 24V) to all external sensors and has overvoltage, overcurrent, short circuit, and reverse connection protection functions. It can still work stably when the vehicle power supply voltage fluctuates (9-36V). The fault diagnosis module monitors the working current, voltage, and temperature status of each braking unit in real time through the CAN bus, establishes a fault code library, and can identify more than 20 common faults such as sensor failure, actuator jamming, and short circuit / open circuit. When a unit fails, it immediately issues a fault alarm signal through the on-board instrument and automatically adjusts the braking force distribution strategy, relying on the remaining normal units to achieve braking, ensuring the basic braking safety of the vehicle and greatly improving the reliability of the system.

[0031] The magnetorheological braking unit is the basic braking execution unit of the system, including a brake disc, a cavity, magnetorheological fluid, and an embedded electromagnetic field generator. The cavity is integrated into the internal interlayer of the brake disc and has a sealed structure. The magnetorheological fluid is fully filled into the cavity. The embedded electromagnetic field generator is precisely assembled on the outside of the cavity and is electrically connected to the ECU. It receives current commands from the ECU and generates a controllable magnetic field.

[0032] The brake disc is made of gray cast iron HT250 through precision casting and machining, with a diameter of 280-350mm and a thickness of 20-30mm. It features high hardness, high wear resistance, and good thermal conductivity. The brake disc has an internal annular sealed jacketed cavity, the shape of which matches the radial structure of the brake disc. The inner wall of the cavity is precision polished and anodized for corrosion protection, with a surface roughness Ra≤0.4μm, preventing the magnetorheological fluid from adhering to the cavity wall and avoiding corrosion that could affect the performance of the magnetorheological fluid. The cavity is a fully sealed structure, with fluororubber sealing rings at the seals. These rings have a Shore hardness of 70-80 and are resistant to high and low temperatures, oil, and aging. The sealing pressure is ≥1.0MPa, effectively preventing magnetorheological fluid leakage and ensuring its sealed storage within the cavity. The cavity also features miniature injection and vent ports for easy addition of magnetorheological fluid and removal of air from the cavity.

[0033] The magnetorheological fluid is a composite of magnetic particles, silicone oil carrier fluid, nanodiamond dispersant, and temperature-controlled ceramic microcapsules. The components work synergistically to ensure the rheological response characteristics and stability of the magnetorheological fluid over a wide temperature range. The magnetic particles employ a Fe3O4@SiO2 core-shell structure. The core Fe3O4 is a high-magnetic-susceptibility magnetic material that provides a strong magnetic response to the magnetorheological fluid, while the outer shell SiO2 is an inert inorganic material that effectively isolates direct contact between magnetic particles, reducing magnetoagglomeration and wear under strong magnetic fields. This also improves the compatibility between the magnetic particles and the silicone oil carrier fluid, enhancing the long-term stability of the magnetorheological fluid. The particle size is controlled within the range of 150-250 nm, preferably 200 nm. This particle size balances the Brownian motion and magnetic response intensity, effectively preventing particle sedimentation while ensuring rapid chain formation under magnetic field conditions.

[0034] Magnetic particles are suspended in the silicone oil carrier fluid at a volume percentage of 35%-55%, preferably 45% vol. This high filling rate is the key to obtaining high yield stress in the magnetorheological fluid, ensuring that a dense chain-like or columnar microstructure can be formed under the action of a magnetic field, generating sufficient shear resistance. The silicone oil carrier fluid is made of high-purity polydimethylsiloxane, with an operating temperature range of -50℃ to above 200℃. It has excellent chemical stability, low volatility and insulation, providing a stable carrier basis for the magnetorheological fluid.

[0035] Adding 2% wt of nanodiamond dispersant with a particle size <100nm to the silicone oil carrier fluid allows it to form a "steric hindrance" in the magnetorheological fluid, interpenetrating between Fe3O4@SiO2 magnetic particles. This disrupts the dense precipitate layer formed by the particles during sedimentation, significantly delaying or even eliminating sedimentation and ensuring the uniformity and rapid response of the magnetorheological fluid after long-term standing. Simultaneously, adding 1% wt of temperature-controlled ceramic microcapsules, which are thermosensitive micro-nano structures, causes the wall material to rupture in low-temperature environments of -40℃ and below, releasing the internal viscosity modifier activator. This effectively reduces the low-temperature viscosity of the magnetorheological fluid, ensuring its fluidity and magnetic responsiveness.

[0036] The embedded electromagnetic field generator consists of 36 sets of high-purity copper electromagnetic coils. All coils are evenly distributed in an array on the outside of the cavity, parallel to the friction surface of the brake disc. This ensures a highly uniform gradient magnetic field is generated on the working surface of the brake disc and within the working gap of the magnetorheological fluid after energization. The electromagnetic coils are electrically connected to the ECU, which can output a gradient DC current of 0-100A. The current value precisely corresponds to the required braking torque. Under the influence of the current, the electromagnetic coils can instantly generate an adjustable magnetic field of 0.5-1.2 Tesla. The magnetic field direction is perpendicular to the friction surface of the brake disc and completely penetrates the working gap of the magnetorheological fluid, achieving precise control of the rheological properties of the magnetorheological fluid.

[0037] The aerodynamic vortex braking unit is the system's high-speed emergency braking auxiliary unit, electrically connected to the ECU. It includes vortex plates and a drive mechanism, mounted behind the vehicle's wheel hub. In its non-operating state, it is flush with the wheel hub, generating no additional wind resistance. Under preset conditions, it is driven by the drive mechanism to unfold to the operating position, generating reverse aerodynamic drag. The vortex plates are hot-pressed from T700 grade high-strength carbon fiber composite material, with a sheet thickness of 0.8mm. This material possesses extremely high specific strength, specific modulus, and lightweight characteristics, capable of withstanding the enormous impact of high-speed airflow, and exhibiting excellent bending, torsional, and fatigue resistance. The outer surface of the vortex plates is entirely coated with a polyetheretherketone (PEEK) coating. PEEK material possesses excellent wear resistance, a low coefficient of friction, chemical stability, and a long-term heat resistance temperature of 150℃, effectively protecting the carbon fiber matrix from erosion by dust particles in high-speed airflow, reducing wind resistance friction, and ensuring the structural integrity of the vortex plates under aerodynamic thermal effects. After the vortex vanes are deployed, their working position is at an angle of 40°-50° to the plane of the hub, preferably 45°. This angle is the optimal angle for generating aerodynamic drag and can efficiently generate controllable turbulence behind the hub.

[0038] The drive mechanism employs a NiTiNol shape memory alloy SMA hinge, which is fixedly connected to the eddy current plate, providing power for its deployment and retraction. A return spring is also included as an auxiliary reset component. The shape memory alloy hinge utilizes the thermoelastic martensitic phase transformation characteristics. After initial shaping and training, it is in the austenitic phase above 80°C, in an deployed state, driving the eddy current plate to a preset working angle; in the martensitic phase below 80°C, it is in a contracted state, causing the eddy current plate to retract and conform to the hub. This hinge uses a Joule heating drive method and is electrically connected to the ECU. The deployment command issued by the ECU controls the current flowing through the hinge's resistive element, raising the hinge temperature to above the phase transformation temperature of 80°C within milliseconds, generating a strong restoring force that drives the eddy current plate to precisely deploy to the working position within 120ms. After power is cut off, the hinge cools down to below the phase transformation temperature through natural convection, and returns to the contracted state under the elastic force of the return spring, causing the eddy current plate to retract smoothly.

[0039] The energy recovery unit is electrically connected to the ECU, the vehicle's drive motor, and the power battery. Its core consists of a motor controller, a rectifier, and an energy storage module. The motor controller receives control commands from the ECU to switch the operating mode of the vehicle's drive motor. During braking, the drive motor switches from drive mode to generator mode, converting the vehicle's kinetic energy into alternating current (AC). This AC is then rectified into direct current (DC) by the rectifier and stored in the vehicle's power battery via the energy storage module. Simultaneously, the counter-torque generated during motor generator generation forms regenerative braking force, which is transmitted to the wheels to participate in vehicle braking. This unit can work in conjunction with magnetorheological braking units and aerodynamic eddy current braking units to recover kinetic energy while simultaneously recovering frictional heat and aerodynamic wind energy during braking, thereby improving the system's overall energy recovery rate.

[0040] In this embodiment, the overall operation process of this system includes: By accurately judging the vehicle's braking conditions through the ECU, the magnetorheological braking unit, aerodynamic eddy current braking unit, and energy recovery unit can work in a graded and coordinated manner. There are three working modes: basic and medium braking conditions, high-speed cruise and medium to high braking conditions, and emergency / high-intensity braking conditions. At the same time, a special adaptation strategy is set for extreme temperature conditions ranging from -40℃ to 150℃ to ensure braking performance under all conditions.

[0041] (1) Basic and moderate braking conditions (vehicle speed < 80km / h, brake pedal opening 0%-70%) When the vehicle is traveling at low speed, and the driver lightly or moderately presses the brake pedal, the brake pedal displacement sensor transmits a braking request signal to the ECU. The ECU, combined with the vehicle speed sensor signal, determines whether the braking condition is basic or moderate. At this time, it controls the pneumatic eddy current braking unit to remain retracted to avoid unnecessary wind resistance loss. Simultaneously, it outputs a DC current of the corresponding gradient to the magnetorheological braking unit, controlling the embedded electromagnetic field generator to produce a magnetic field of 0.5-0.8 Tesla. Under the action of the magnetic field, the Fe3O4@SiO2 magnetic particles in the magnetorheological fluid instantly align along the magnetic field lines to form a chain-like microstructure, causing the magnetorheological fluid to transform from a free-flowing Newtonian fluid to a Bingham-like plastic body, generating a yield stress of 50-70 kPa. When the brake disc moves relative to the brake disc, it overcomes this yield stress to generate a controllable braking torque, achieving smooth braking.

[0042] At the same time, the ECU sends a working command to the energy recovery unit, controlling the vehicle drive motor to switch to power generation mode, converting the vehicle's kinetic energy into electrical energy and storing it in the power battery. The regenerative braking force and the magnetorheological braking force work together to complete the braking. Under this condition, the energy recovery efficiency of the energy recovery unit can reach the optimal level, effectively reducing the overall vehicle energy consumption.

[0043] (2) High-speed cruising and moderate to heavy braking conditions (vehicle speed ≥ 80 km / h, brake pedal opening 0%-70%) When the vehicle is cruising at high speed and the driver requests moderate braking, the ECU determines the operating condition based on the signals from the vehicle speed sensor and pedal displacement sensor. It still uses the magnetorheological braking unit as the main braking force, outputting a magnetic field control current of 0.8-1.0 Tesla to it, so that the magnetorheological fluid generates a yield stress of 70-90 kPa to meet the braking force requirements of high-speed braking; the aerodynamic eddy current braking unit remains in the retracted state to avoid additional wind resistance at high speeds.

[0044] The ECU, in conjunction with the battery status signal from the battery management system (BMS), finely adjusts the regenerative braking ratio of the energy recovery unit. If the remaining charge of the power battery is low, the energy recovery power is increased to maximize the recovery of vehicle kinetic energy; if the power battery is fully charged, the regenerative braking ratio is appropriately reduced, and braking is completed only by the magnetorheological braking unit to avoid battery overcharging and achieve the optimal balance between braking force distribution and energy recovery.

[0045] (3) Emergency / High-intensity braking conditions (vehicle speed ≥ 80 km / h or brake pedal opening > 70% or a collision warning signal is received) When the driver slams on the brake pedal while the vehicle is traveling at high speed, or when the ECU receives an emergency signal from the vehicle collision warning system, the ECU immediately determines that it is an emergency / high-intensity braking condition and instantly sends full-load operating commands to the magnetorheological braking unit, the aerodynamic eddy current braking unit, and the energy recovery unit to achieve vector superposition of the braking forces of the three units and produce a peak braking effect.

[0046] At this moment, the ECU instantly increases the current of the electromagnetic coil to 100A, the electromagnetic field generator excites a peak magnetic field of 1.2 Tesla, the magnetic particles in the magnetorheological fluid rapidly form a dense network microstructure, the yield stress rises to a peak of 100kPa, generating a powerful basic braking force. Its full-chain response time of current-magnetic field-particle chaining-fluid solidification is ≤0.05 seconds, realizing the instantaneous establishment of braking force; The ECU synchronously supplies power to the shape memory alloy hinge, driving the vortex vane to expand to a working position at 45° with the wheel hub within 120ms. The vortex vane forcibly strips away the high-speed airflow passing through the wheel hub, forming a high-intensity, controllable low-pressure turbulent wake vortex region behind the wheel hub. According to Bernoulli's principle, the high-pressure airflow in front of the vehicle flows towards the low-pressure wake vortex region, generating a reverse aerodynamic drag with a drag coefficient Cd=1.8. This drag acts directly on the vehicle body, providing additional braking force for the vehicle, and the aerodynamic effect propagates at the speed of sound without mechanical transmission delay. Operating at the maximum power allowed by the system, the drive motor converts the vehicle's kinetic energy and braking friction heat into electrical energy at maximum power output, generating maximum regenerative braking force. This force, in conjunction with magnetorheological braking force and aerodynamic drag, significantly increases the vehicle's deceleration and effectively shortens the high-speed emergency braking distance.

[0047] Under this condition, the ECU will also collect wheel speed and yaw rate signals in real time, integrate ABS and ESC functions, and change the distribution of braking force to each wheel by finely adjusting the current output of the magnetorheological braking unit of each wheel to prevent wheel lock-up; at the same time, it will finely adjust the unfolding angle of the eddy vanes (within the range of 40°-50°) according to the vehicle body attitude to ensure the stability of the vehicle body during braking and maximize the use of ground adhesion.

[0048] The magnetorheological-pneumatic coordinated braking system of this invention features a rationally designed unit structure and a precise and efficient coordinated working mechanism. Through the deep integration of magnetorheological and pneumatic technologies, coupled with multi-dimensional energy recovery by the energy recovery unit, it completely solves the technical pain points of traditional braking systems, such as slow response, dust pollution, poor climate adaptability, and low energy recovery rate. It achieves a full-range braking response of ≤50ms, dust-free braking with zero mechanical contact, and stable braking in all climates from -40℃ to 150℃, while increasing the total energy recovery rate to 40%. At the same time, the system eliminates the need for pipelines, boosters, and reservoirs in traditional hydraulic braking systems, offering advantages in lightweighting and integration. This significantly improves the safety, environmental friendliness, and energy efficiency of vehicle braking, making it highly valuable for industrial application and promotion.

[0049] Example 2 This embodiment discloses a control method for a magnetorheological-pneumatic coordinated braking system; like Figure 2 As shown, a control method for a magnetorheological-pneumatic coordinated braking system includes: A control method for a magnetorheological-pneumatic coordinated braking system includes: Step S1: Real-time acquisition of vehicle braking request signals and status parameters, the status parameters including at least vehicle speed signals and brake pedal opening signals.

[0050] When the driver initiates a braking request by operating the brake pedal, or when the vehicle's autonomous driving system triggers an automatic braking command, the ECU first starts a signal acquisition program to obtain braking request signals and vehicle status parameters in real time.

[0051] The braking request signal is acquired by a high-precision displacement sensor at the brake pedal. The sensor converts the mechanical displacement of the brake pedal into a linear electrical signal. The amplitude of the electrical signal is positively correlated with the pedal depth and speed, accurately representing the braking intention of the driver or automatic system. The status parameters include at least the vehicle speed signal and the brake pedal opening signal. The vehicle speed signal is acquired by the vehicle wheel speed sensor / vehicle speed sensor and represents the real-time speed of the vehicle. The brake pedal opening signal is calculated by the displacement sensor in combination with the full displacement of the pedal and represents the percentage of the pedal depth to the total travel.

[0052] All of the above signals are sent to the ECU in real time at a millisecond transmission rate. The ECU performs preprocessing such as filtering and amplification on the received electrical signals to eliminate interference noise during signal transmission, ensuring the accuracy and stability of the signals and providing a reliable data foundation for subsequent operating condition judgment.

[0053] Step S2: Based on the vehicle speed signal and the brake pedal opening signal, determine whether the current braking condition is a normal braking mode or an emergency braking mode. The ECU has a built-in operating condition judgment logic module that uses the pre-processed vehicle speed signal and brake pedal opening signal as the basis for judgment. It compares the vehicle speed signal with a first preset threshold (80km / h) and the brake pedal opening signal with a second preset threshold (70%). Based on the comparison results, it determines whether the current braking condition is normal braking mode or emergency braking mode. The specific judgment rules are as follows: When the vehicle's real-time speed is below 80km / h and the brake pedal opening is below 70%, it is determined to be in normal braking mode. This mode corresponds to the daily operating conditions of low-speed driving and smooth braking. The braking demand is small and there is no need for the pneumatic vortex braking unit to intervene. When the vehicle's real-time speed is higher than or equal to 80 km / h, or the brake pedal opening is higher than or equal to 70%, it is determined to be in emergency braking mode. This mode is for emergency situations where the vehicle brakes at high speed and the driver presses the pedal hard. The braking demand is high, and all braking units need to be activated to achieve forced braking.

[0054] The condition judgment process in this step is completed by the ECU within milliseconds, ensuring a rapid response to braking commands with no significant judgment delay, thus meeting the real-time requirements of vehicle braking.

[0055] Step S3: When it is determined to be a normal braking mode, control the aerodynamic eddy current braking unit to remain in the retracted state, and coordinate the control of the magnetorheological braking unit and the energy recovery unit to perform braking according to the target braking force.

[0056] Based on the operating condition judgment result in step S2, the ECU sends differentiated control commands to each braking unit to execute the cooperative braking strategy in the normal braking mode or emergency braking mode respectively, so as to achieve reasonable distribution of braking force and efficient coordination of each unit.

[0057] When the ECU determines that it is in the normal braking mode, it controls the aerodynamic eddy current braking unit to remain in the retracted state to prevent it from deploying and generating additional wind resistance, which would increase vehicle energy consumption. At this time, braking is achieved only through the coordinated operation of the magnetorheological braking unit and the energy recovery unit. The specific control process is as follows: Based on the strength of the braking request signal and combined with parameters such as the vehicle's real-time load and road adhesion, the ECU calculates the target braking force required by the vehicle through its built-in algorithm. The ECU prioritizes the use of the energy recovery unit, controlling the vehicle's drive motor to switch from drive mode to generator mode, converting the vehicle's kinetic energy into electrical energy and storing it in the power battery. At the same time, the counter-torque generated by the motor forms regenerative braking force, which is the primary source of braking force for conventional braking, maximizing energy recovery and improving the vehicle's energy utilization efficiency. If the regenerative braking force output by the energy recovery unit does not reach the target braking force, the ECU sends a current control command to the magnetorheological braking unit. Based on the braking force difference, the ECU adjusts the current input to the electromagnetic coil of the magnetorheological braking unit, controls the electromagnetic coil to generate a magnetic field of corresponding strength, changes the rheological properties of the magnetorheological fluid, and causes the magnetorheological braking unit to output supplementary braking force until the resultant force of the regenerative braking force and the magnetorheological braking force reaches the target braking force. During braking, the ECU collects the actual output values ​​of the regenerative braking force and the magnetorheological braking force in real time, compares them with the target braking force, and dynamically fine-tunes the current of the electromagnetic coil to achieve stepless and precise control of the braking force, ensuring smooth vehicle braking and improving braking comfort.

[0058] In conventional braking mode, the magnetorheological braking unit has no mechanical contact wear and no braking dust is generated throughout the process. At the same time, the efficient operation of the energy recovery unit effectively reduces the vehicle's energy consumption, making it especially suitable for low-speed urban driving conditions of new energy vehicles and significantly extending the vehicle's driving range.

[0059] When the ECU determines that it is in emergency braking mode, it immediately activates the three-modal coordinated braking strategy, simultaneously activating the magnetorheological braking unit, the aerodynamic eddy current braking unit, and the energy recovery unit. This allows all three to output braking force synchronously, achieving vector superposition of braking forces and producing a super-force braking effect, effectively shortening the braking distance. The specific control process is as follows: The ECU instantly outputs a peak current to the electromagnetic coil of the magnetorheological braking unit, which excites a peak magnetic field of 1.2 Tesla. Under the action of the strong magnetic field, the magnetorheological fluid rapidly forms a dense chain / network structure, and the yield stress rises to a peak value of 100 kPa, generating the maximum basic braking force. The full-chain response time of the magnetorheological braking unit is ≤0.05 seconds, realizing instantaneous establishment of braking force and no braking idle stroke. The ECU synchronously sends a power-on command to the drive mechanism of the aerodynamic vortex braking unit. Within 120ms, the drive mechanism drives the vortex plate to unfold to the preset working position. The vortex plate generates controllable turbulence behind the wheel hub, producing a reverse aerodynamic drag with a drag coefficient Cd=1.8. This aerodynamic drag acts directly on the vehicle body, providing additional forced dynamic force to the vehicle. Moreover, the aerodynamic effect propagates at the speed of sound, with no mechanical transmission delay, and can quickly intervene in braking. The ECU controls the energy recovery unit to operate at the maximum power allowed by the system, driving the motor to generate electricity at full load, converting the vehicle's kinetic energy and frictional heat energy during braking into electrical energy, and at the same time generating the maximum regenerative braking force, which participates in braking as a third braking force. The braking force output by the three units acts synchronously on the vehicle, forming a total braking force far exceeding that of a single unit, achieving peak deceleration. During braking, the ECU collects real-time state parameters such as vehicle wheel speed and yaw rate, integrating ABS anti-lock braking and ESC vehicle stability control functions. By finely adjusting the braking force distribution of each wheel in the magnetorheological braking unit and the deployment angle of the eddy current plates in the aerodynamic eddy current braking unit, it prevents wheel lock-up, suppresses vehicle sideslip, ensures vehicle driving stability during emergency braking, and maximizes the use of ground adhesion.

[0060] The magnetorheological-pneumatic coordinated braking system control method of this embodiment achieves intelligent coordinated regulation of the braking unit based on precise identification of operating conditions. The control method relies on the millisecond-level signal processing and operating condition judgment capabilities of the ECU. The entire process control delay from signal acquisition to braking force output is ≤50ms. The fast response of the magnetorheological braking unit (≤0.05s) and the deployment action of the pneumatic eddy current braking unit (120ms) work together to achieve a braking response speed that is far superior to the delay of more than 200ms of traditional hydraulic braking. This fully meets the stringent requirements of L4 autonomous driving for braking response and can effectively shorten the braking distance by more than 15% during emergency braking, significantly improving driving safety.

[0061] By differentiating control between normal and emergency braking modes, stepless and precise distribution of braking force is achieved. Under normal operating conditions, the braking force of magnetorheological braking and energy recovery is dynamically compensated to ensure smooth braking without nose-diving or shaking. Under emergency operating conditions, the three-modal braking force vector superposition, combined with the integrated control of ABS / ESC, allows for real-time fine adjustment of the braking force of each wheel and the eddy current plate deployment angle, effectively preventing wheel lock-up and vehicle sideslip, maximizing the use of ground adhesion, and ensuring braking stability under high-speed and complex road conditions.

[0062] Energy conservation and environmental protection are optimized in two ways. The control method prioritizes the use of the energy recovery unit under normal operating conditions, combined with magnetorheological non-mechanical contact braking, to completely eliminate dust pollution from traditional friction braking, while reducing wear on braking components and lowering system maintenance costs. The multi-dimensional energy recovery strategy achieves comprehensive recovery of kinetic energy, frictional heat energy and aerodynamic wind energy, increasing the total energy recovery rate to over 40%. Compared with traditional braking systems, energy consumption is reduced by 20%, the driving range of new energy vehicles can be extended by more than 15%, and the fuel consumption of fuel vehicles is reduced by 0.5-1.0L per 100 kilometers, taking into account both environmental protection and energy conservation.

[0063] The system's adaptability to all weather and operating conditions is significantly enhanced. Through adaptive compensation control under extreme temperature conditions, it triggers viscosity adjustment of magnetorheological fluid and micro-compensation of magnetic field current at low temperatures, and achieves adaptive enhancement of magnetic field strength and heat dissipation coordination at high temperatures. This ensures that the system's performance degradation is less than 5% within the range of -40℃ to 150℃, completely solving the pain points of traditional hydraulic braking such as low-temperature fluid solidification and high-temperature air resistance. At the same time, the detailed control of low-speed / medium-high-speed conventional braking adapts to different driving scenarios such as urban roads and highway cruising. The control logic fits the actual driving needs and has strong engineering practicality.

[0064] Example 3 This embodiment discloses a vehicle including the magnetorheological-pneumatic coordinated braking system described in any of the above embodiments.

[0065] In this embodiment, the structure and function of each component of the car are similar to those in the previous embodiment, and will not be repeated here.

[0066] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A magnetorheological-pneumatic coordinated braking system, characterized in that, include: The brake pedal is used to generate a braking request signal; The electronic control unit (ECU) is electrically connected to the brake pedal and is used to receive the braking request signal and vehicle status signal, and generate and send control commands according to a preset strategy. The magnetorheological braking unit, electrically connected to the ECU, includes a brake disc, a cavity disposed within the brake disc, a magnetorheological fluid filled within the cavity, and an embedded electromagnetic field generator. Upon receiving a command from the ECU, the embedded electromagnetic field generator generates a controllable magnetic field, altering the rheological properties of the magnetorheological fluid to generate braking force. The pneumatic vortex braking unit is electrically connected to the ECU and includes a vortex plate and a drive mechanism. After receiving the command from the ECU, the drive mechanism drives the vortex plate to expand to the working position under preset conditions, creating controllable turbulence behind the wheel hub and generating reverse aerodynamic drag. The energy recovery unit is connected to the ECU and the vehicle's drive motor. After receiving instructions from the ECU, it converts the vehicle's kinetic energy into electrical energy for recovery and generates regenerative braking force.

2. The magnetorheological-pneumatic coordinated braking system as described in claim 1, characterized in that, The magnetorheological fluid comprises magnetic particles, silicone oil carrier fluid, and dispersant; the magnetic particles are Fe3O4@SiO2 core-shell structured particles, with Fe3O4 as the core and SiO2 as the outer shell; the dispersant is a nanodiamond dispersant.

3. The magnetorheological-pneumatic coordinated braking system as described in claim 2, characterized in that, The magnetic particles have a particle size of 150-250 nm; the magnetic particles are suspended in the silicone oil carrier liquid at a volume percentage of 35%-55%.

4. The magnetorheological-pneumatic coordinated braking system as described in claim 1, characterized in that, The embedded electromagnetic field generator includes multiple sets of electromagnetic coils arranged in an array, which are used to generate a gradient magnetic field under the control of the ECU to adjust the yield stress of the magnetorheological fluid.

5. The magnetorheological-pneumatic coordinated braking system as described in claim 1, characterized in that, The driving mechanism is a shape memory alloy hinge, and the vortex plate is made of carbon fiber composite material.

6. The magnetorheological-pneumatic coordinated braking system as described in claim 1, characterized in that, The surface of the vortex plate is coated with a polyetheretherketone coating, and the working position of the vortex plate after it is deployed forms an angle of 40°-50° with the plane where the hub is located.

7. The magnetorheological-pneumatic coordinated braking system as described in claim 1, characterized in that, The magnetorheological fluid also contains temperature-controlled ceramic microcapsules, which are used to release activators at low temperatures to reduce viscosity.

8. A control method for a magnetorheological-pneumatic coordinated braking system, characterized in that, include: Step S1: Real-time acquisition of vehicle braking request signals and status parameters, wherein the status parameters include at least vehicle speed signals and brake pedal opening signals; Step S2: Based on the vehicle speed signal and the brake pedal opening signal, determine whether the current braking condition is a normal braking mode or an emergency braking mode. Step S3: When it is determined to be a normal braking mode, control the aerodynamic eddy current braking unit to remain in the retracted state, and coordinate the control of the magnetorheological braking unit and the energy recovery unit to perform braking according to the target braking force. When the emergency braking mode is detected, the magnetorheological braking unit, the aerodynamic eddy current braking unit, and the energy recovery unit are activated simultaneously, so that the three work together to generate braking force and achieve three-mode coordinated braking.

9. The control method for a magnetorheological-pneumatic coordinated braking system as described in claim 8, characterized in that, Determining whether the current braking condition is in normal braking mode or emergency braking mode specifically includes: The vehicle speed signal is compared with a first preset threshold, and the brake pedal opening signal is compared with a second preset threshold. When the vehicle speed is lower than the first preset threshold and the brake pedal opening is lower than the second preset threshold, it is determined to be in normal braking mode; When the vehicle speed is higher than or equal to the first preset threshold, or when the brake pedal opening is higher than or equal to the second preset threshold, it is determined to be an emergency braking mode.

10. A car, characterized in that, The system includes a magnetorheological-pneumatic coordinated braking system as described in any one of claims 1-7.

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