A steering safety management and control system and method for intelligent driving

Abstract

The application discloses a kind of steering safety management and control systems and methods of intelligent driving, including by the steering function module of multiphase composite alloy material and the field energy control module coupled therewith, steering function module is set in the steering transmission path of drive-by-wire steering system, the damping characteristic of this material is changed in succession in the range of 10 times or more under the action of external field energy and geometric morphology changes.Field energy control module realizes damping adjustment and shape control by applying adjustable field energy, mode decision unit determines safety situation and selects corresponding working mode according to sensor signal.In normal driving mode, the resonant frequency of steering system is reduced to 8Hz, and the steering wheel shaking is reduced by 64%.In emergency obstacle avoidance mode, steering response delay is shortened to 28ms.The application solves the technical problems of existing drive-by-wire steering system structure redundancy, collision irreversible deformation and power failure out of control, and realizes full-working-condition steering safety management and control.

Description

Technical Field

[0001] This invention belongs to the field of steer-by-wire safety control technology, and particularly relates to a steering safety management system and method for intelligent driving. Background Technology

[0002] steer-by-wire systems eliminate the mechanical connection between the steering wheel and the steering wheels, transmitting steering commands entirely through electrical signals. They offer advantages such as fast response, ease of integration into autonomous driving, and flexible layout, making them a core component of intelligent driving vehicles. Currently, steer-by-wire systems typically include a steering actuator, a tie rod, steering sensors, and an electronic control unit (ECU). The steering actuator receives commands from the ECU and drives the steering wheels to rotate. The tie rod transmits the actuator's output to the steering knuckle. Sensors collect signals such as steering torque and wheel angle and feed them back to the ECU, forming a closed-loop control system. To ensure system safety, existing steer-by-wire systems typically employ electronic redundancy schemes such as dual-motor redundancy and dual-controller redundancy, and incorporate hydraulic dampers or spring damping mechanisms in the steering column or actuator to attenuate road vibrations. The tie rod, as the force transmission component between the steering actuator and the steering knuckle, is typically made of steel or aluminum alloy. Furthermore, to achieve electromagnetic compatibility, the ECU usually has an independent shielded housing, and the signal harness has an independent shielding layer.

[0003] However, the aforementioned existing technologies still have the following shortcomings: First, the damping coefficient of hydraulic dampers or spring damping mechanisms is fixed or adjustable within a limited range, and cannot be adjusted in real time according to driving conditions, resulting in an inherent contradiction between high-frequency road vibrations and driver handling feel. Second, the steering tie rod is a rigid rod that cannot recover itself after irreversible plastic deformation under collision impact, and cannot actively change its length before a collision to optimize wheel toe angle. Collision safety relies on the vehicle body's energy-absorbing structure and lacks the steering system's own active intervention capability. Third, the magnetic field response damping adjustment and temperature response shape memory functions are implemented by different materials or components, and are independently set and controlled, with no coordination in response timing. Furthermore, each requires independent drive circuits and installation space, increasing system complexity and manufacturing costs. Fourth, the electromagnetic shielding housing needs to be installed separately after the electronic control unit is assembled, and cannot be integrated with the structural body of the steering actuator or tie rod. The shielding effect depends on the assembly quality, and there is a risk of shielding discontinuity in the electrical connection between the signal harness shielding layer and the electronic control unit shielding housing. Fifth, the steering actuator, tie rod, damper, shape memory actuator, and other components are all independent and require separate design and assembly. The large number of components, long transmission chains, and accumulated response delays limit the integration and responsiveness improvement potential of the steering system. Sixth, when the vehicle's main power supply is interrupted, the steer-by-wire system completely loses its steering control capability, and the steering wheels cannot return to the center position due to the yaw angle at the moment of power failure. Existing solutions lack an autonomous and safe self-centering mechanism that does not rely on external power. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the present invention provides a steering safety control system and method for intelligent driving, which solves the problems of structural redundancy and response lag caused by the independent setting of each functional component in the existing steer-by-wire system, irreversible deformation of the tie rod during a collision and inability to actively intervene, and lack of autonomous self-centering capability after power failure without relying on external power source.

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

[0006] A steering safety control system and method for intelligent driving, comprising:

[0007] The steering function module is made of multiphase composite alloy material. The damping characteristics of the multiphase composite alloy material change under the action of external field energy, and its geometric shape changes under the action of external field energy.

[0008] The field energy regulation module is coupled to the steering function module and is used to apply adjustable field energy to the steering function module;

[0009] The steering function module is located in the steering transmission path of the steer-by-wire system;

[0010] The field energy control module applies the adjustable field energy to continuously change the damping characteristics of the multiphase composite alloy material within a range of more than 10 times, and applies the adjustable field energy to cause deformation of the multiphase composite alloy material.

[0011] Preferably, the multiphase composite alloy material uses a Ni-Ti shape memory alloy as a matrix, and magnetorheological elastomer particles are distributed in the matrix; the field energy control module applies a magnetic field and / or electric field to the multiphase composite alloy material, causing the system to switch between at least two of the following modes:

[0012] In the first mode, the field energy control module applies a first magnetic field to the multiphase composite alloy material, causing the magnetorheological elastomer particles to generate a first damping.

[0013] In the second mode, the field energy control module reduces or cuts off the first magnetic field and applies an electric field, thereby reducing the elastic modulus of the Ni-Ti alloy matrix and the equivalent rotational inertia of the steering function module.

[0014] In the third mode, the field energy control module applies a pulsed electric field to excite the shape memory effect of the Ni-Ti alloy matrix, causing the steering function module to deform.

[0015] In the fourth mode, the field energy regulation module releases electrical energy from the energy storage element to apply a second magnetic field to the multiphase composite alloy material. The strength of the second magnetic field is greater than that of the first magnetic field, causing the magnetorheological elastomer particles to reach a magnetic saturation state, and the steering function module switches to a restricted state.

[0016] In the fifth mode, the steering function module uses external vibration energy to generate electrical energy to stimulate the shape memory effect, causing the steering function module to return to a preset position.

[0017] Preferably, when the steering function module is a tie rod, the deformation of the tie rod in the third mode is axial extension and contraction with a stroke of 5mm to 20mm, and the axial displacement does not exceed ±0.5mm when switching to the restricted state in the fourth mode; when the steering function module is the rotor or piston of the steering actuator, the equivalent moment of inertia of the rotor or piston in the second mode is reduced by more than 50%.

[0018] Preferably, the steering function module includes:

[0019] A steering actuation module, disposed in the steering column or worm gear transmission mechanism of the steer-by-wire system, the steering actuation module comprising a moving component made of the multiphase composite alloy material; and

[0020] A tie rod module connects the steering actuation module and the steering knuckle, the tie rod module comprising a rod body made of the multiphase composite alloy material;

[0021] The field energy regulation module is coupled to the steering execution module and the tie rod module respectively;

[0022] A protective housing covers the outside of the field energy regulation module;

[0023] The multiphase composite alloy material uses Ni-Ti alloy as the matrix, and magnetorheological elastomer particles are distributed in the matrix. The surface of the matrix is ​​coated.

[0024] The field energy control module controls the magnetic field and / or electric field applied to the multiphase composite alloy material, enabling the system to switch between normal driving mode, emergency obstacle avoidance mode, pre-collision triggering mode, collision protection mode and power failure mode.

[0025] In the normal driving mode, the field energy control module applies a magnetic field to the multiphase composite alloy material, causing the magnetorheological elastomer particles to generate damping.

[0026] In the emergency obstacle avoidance mode, the field energy control module reduces the magnetic field and applies an electric field to heat the multiphase composite alloy material, thereby reducing the equivalent moment of inertia of the multiphase composite alloy material.

[0027] In the pre-collision triggering mode, the field energy control module applies a pulsed electric field to the crossbar module to excite the shape memory effect of the Ni-Ti alloy matrix, causing the rod to undergo expansion and contraction deformation.

[0028] In the collision protection mode, the field energy regulation module releases electrical energy from the energy storage element to apply a magnetic field to the multiphase composite alloy material, causing the magnetorheological elastomer particles to reach magnetic saturation, and the horizontal tie rod module switches to a confined state; and

[0029] In the power-off mode, the tie rod module uses road vibration energy to generate electrical energy, which is then rectified, stored, and released to the heating element to activate the shape memory effect, causing the steering wheel to return to the straight driving position.

[0030] Preferably, in the multiphase composite alloy material:

[0031] The Ni-Ti alloy has a Ni content of 50.0 at% to 50.8 at%, a Ti content of 49.2 at% to 50.0 at%, and a martensitic transformation temperature of -20°C to 80°C.

[0032] The magnetorheological elastomer microparticles have a particle size of 10 μm to 50 μm and a volume fraction of 5% to 15%.

[0033] The coating comprises an inner layer and an outer layer, wherein the inner layer is a Ni-Fe alloy layer with a thickness of 10 μm to 20 μm, and the outer layer is a Cu layer with a thickness of 5 μm to 10 μm;

[0034] The magnetorheological elastomer is composed of a two-component room temperature vulcanizing silicone rubber and carbonyl iron powder. The particle size of the carbonyl iron powder is 1 μm to 5 μm. The mass ratio of the silicone rubber to the carbonyl iron powder is 100:200 to 100:400. The magnetorheological elastomer is cured and formed under a pre-applied magnetic field of 0 mT to 700 mT.

[0035] Preferably, the steering execution module further includes:

[0036] The container has an internal cavity, and the moving part is disposed within the cavity;

[0037] An excitation coil is disposed around the periphery of the receiving cavity and coupled to the field energy control module;

[0038] A heating element is disposed inside the moving part and coupled to the field energy control module;

[0039] A temperature sensing element is disposed on the surface of the moving part and coupled to the field energy control module;

[0040] Vibration sensing elements and / or strain sensing elements are disposed inside the moving part and coupled to the field energy control module;

[0041] The tie rod module also includes:

[0042] An excitation coil sleeve is fitted over the outside of the rod and coupled to the field energy control module;

[0043] A heating element is disposed inside the rod body and coupled to the field energy control module;

[0044] Displacement sensing elements are disposed at both ends of the rod and coupled to the field energy control module. The displacement sensing elements are linear displacement sensing elements with a measurement range of 0 mm to 50 mm.

[0045] A rectifier energy storage unit is disposed at one end of the rod and coupled to the heating element.

[0046] Preferably, the field energy regulation module includes:

[0047] A magnetic field control unit, coupled to the excitation coil, receives a first command output by the mode decision unit and outputs an adjustable current to the excitation coil;

[0048] A thermal field control unit, coupled to the heating element, receives a second command output by the mode decision unit and outputs an adjustable current to the heating element;

[0049] The state acquisition unit is coupled to the temperature sensing element, vibration sensing element, strain sensing element and displacement sensing element, and processes the acquired signals and outputs them to the mode decision unit.

[0050] The mode decision unit, coupled with the magnetic field control unit, thermal field control unit, state acquisition unit, vehicle intelligent driving system, vehicle attitude sensor, and collision prediction sensor, generates decision commands based on the signals output by the state acquisition unit, the driving state output by the vehicle intelligent driving system, the attitude information output by the vehicle attitude sensor, and the prediction information output by the collision prediction sensor. It then outputs the first command to the magnetic field control unit and the second command to the thermal field control unit.

[0051] The energy storage control unit is coupled to the rectifier energy storage unit, monitors the energy storage status of the rectifier energy storage unit, and outputs an energy storage release signal to the thermal field control unit in the power-off mode.

[0052] Preferably, in the emergency obstacle avoidance mode, the field energy control module cuts off or reduces the current of the excitation coil and applies a pulse current with a duration of 50ms to 200ms through the heating element, thereby reducing the elastic modulus of the Ni-Ti alloy matrix by 20% to 40%; in the pre-collision trigger mode, the field energy control module applies a pulse current with a frequency of 5Hz to 20Hz and a duty cycle of 30% to 70% to the heating element, causing the rod to undergo a 5mm to 20mm extension and contraction deformation; in the collision protection mode, the field energy control module burns out the fuse of the excitation coil and releases the energy stored in the energy storage capacitor, causing the magnetorheological elastomer particles to reach a magnetic saturation state, the equivalent damping coefficient of the crossbar module is more than 20 times the conventional value, and the axial displacement of the rod under the confined state does not exceed ±0.5mm.

[0053] Preferably, in the power-off mode, the rectifier energy storage unit rectifies the induced current and stores it in a capacitor. The stored electrical energy is periodically released to the heating element to intermittently heat the rod. The output power of the rectifier energy storage unit is 50mW to 500mW, the starting power of the heating element is 100mW to 1000mW, and the energy stored in the capacitor is 10J to 100J. The straight-line driving position refers to the position where the steering angle of both the left and right front wheels is 0° when the vehicle is driving straight on a level road. It is determined by monitoring the axial displacement of the rod through the displacement sensing element. The tie rod module also has a mechanical energy storage unit, which includes an elastic element and a locking element. The elastic element is kept compressed by the locking element when the field energy control module is energized. In the power-off mode, the locking element releases the elastic element, and the elastic potential energy of the elastic element pushes the rod to move towards the straight-line driving position.

[0054] Preferably, a steering safety control method for intelligent driving includes the following steps:

[0055] S1. Collect steering torque and vibration signals through vibration sensing elements and / or strain sensing elements, collect temperature signals through temperature sensing elements, and collect axial displacement signals of the tie rod through displacement sensing elements.

[0056] S2. The state acquisition unit of the field energy regulation module receives the signal collected in step S1, processes it, and outputs it to the mode decision unit. The mode decision unit determines the safety situation based on the signal, vehicle driving status, and collision prediction information: when the collision prediction sensor outputs a collision time of less than 300ms, it is determined to be a pre-collision situation; when the collision sensor detects that the acceleration exceeds a preset threshold, it is determined to be a collision in progress situation; when the field energy regulation module detects that the main power supply is cut off, it is determined to be a power failure situation; in other cases, it is determined to be a normal situation or an emergency obstacle avoidance situation based on the amplitude of the steering torque signal.

[0057] S3. The mode decision unit selects the target mode according to the safety situation determined in step S2, and outputs corresponding instructions to the magnetic field control unit and / or thermal field control unit respectively: normal situation corresponds to normal driving mode, emergency obstacle avoidance situation corresponds to emergency obstacle avoidance mode, pre-collision situation corresponds to pre-collision triggering mode, collision in progress situation corresponds to collision protection mode, and power failure situation corresponds to power failure mode.

[0058] The technical effects and advantages of the intelligent driving steering safety control system and method of the present invention are as follows:

[0059] 1. This invention integrates a multiphase composite alloy steering module into the steering transmission path of a steer-by-wire system. By applying an adjustable field energy to the steering module using a field energy control module, the module's damping characteristics and geometry change under the influence of a magnetic field and field energy, respectively, thus achieving intelligent control of the steering system hardware. The steering module simultaneously performs force transmission, damping adjustment, and deformation actuation, eliminating the need for separate dampers and deformation actuators, simplifying the system structure, and reducing manufacturing costs and assembly complexity.

[0060] 2. This invention applies adjustable field energy through a field energy control module, allowing the damping characteristics of the multiphase composite alloy material to continuously vary within a range of more than 10 times. This enables the steering system to adjust the equivalent damping coefficient in real time according to driving conditions. During normal driving, it provides moderate damping to filter out high-frequency road vibrations and improve driving comfort; when a rapid response is needed, it reduces damping to decrease system inertia and improve steering sensitivity. Compared to traditional solutions with fixed damping, the steering feel can be steplessly adjusted from "heavy and stable" to "light and sensitive," adapting to the differentiated needs of different vehicle speeds and road conditions.

[0061] 3. This invention applies adjustable field energy to the steering module through a field energy regulation module, causing deformation of the multiphase composite alloy material. This allows the steering module to actively change its geometry when subjected to external impacts, extending safety control from "collision avoidance" to "active protection during a collision." The steering tie rod can generate a preset travel extension and contraction deformation within milliseconds before a collision to optimize the wheel camber angle. During a collision, it absorbs impact energy using the material's high damping characteristics and recovers itself after the collision through shape memory effect, achieving active safety and self-recovery at the structural level.

[0062] 4. This invention utilizes a composite structure of a Ni-Ti shape memory alloy matrix and magnetorheological elastomer microparticles to enable the same material to simultaneously possess two intelligent characteristics: magnetic field response damping regulation and temperature / electric field response shape memory. The two response mechanisms are independent at the microstructural level but synergistic at the macroscopic functional level, without interfering with each other. The damping response time of the magnetorheological elastomer microparticles under magnetic field action is on the order of milliseconds, while the shape memory response time of the Ni-Ti matrix is ​​on the order of tens of milliseconds. The timescales of the two responses are matched, allowing them to function sequentially or simultaneously during the same operating condition transition, without requiring separate actuators and control logic for each function.

[0063] 5. This invention utilizes a Ni-Fe / Cu gradient composite coating on the surface of a multiphase composite alloy material to enable the steering module itself to possess electromagnetic shielding capabilities. The steering actuator housing and tie rod itself constitute a Faraday cage shielding structure, eliminating the need for an additional independent electromagnetic shielding cover. The shielding layer of the steering ECU signal harness employs the same composite coating process as the material surface coating, constructing a complete electromagnetic immune barrier at the material level, ensuring the pure transmission of sensor signals and control commands in complex electromagnetic environments. Compared to traditional solutions that require a separate shielding cover and only achieve shielding after assembly, this invention completes the shielding layer formation during the material preparation stage, eliminating the need for additional shielding treatment after assembly, reducing assembly costs and improving shielding reliability.

[0064] 6. This invention applies a strong, instantaneous magnetic field to the multiphase composite alloy material by releasing electrical energy from the energy storage element through the field energy regulation module. This causes the magnetorheological elastomer particles to reach magnetic saturation within milliseconds, causing the equivalent damping coefficient of the multiphase composite alloy material to surge to more than 20 times the conventional value. The steering function module switches to a restricted state with an axial displacement not exceeding ±0.5 mm, maintaining structural integrity even under impact forces. This physical constraint mechanism does not rely on sensor signal processing or software algorithm response; it is a passive safety protection mechanism entirely based on the material's physical properties. Its response speed is more than an order of magnitude faster than electronic control systems, fundamentally solving the problem of electronic control systems potentially failing due to signal delays or power interruptions during a collision.

[0065] 7. This invention utilizes the magnetostrictive effect in a multiphase composite alloy material to convert road vibration energy into electrical energy. After rectification and energy storage, the energy is released to a heating element to stimulate the shape memory effect, enabling the steering module to autonomously return to center using road vibration energy even under the worst-case scenario of a complete vehicle power outage. This mechanism does not rely on external power sources or active control signals; it is a self-circulating energy conversion path of "mechanical energy → electrical energy → thermal energy," providing ultimate safety redundancy for steer-by-wire systems that does not depend on traditional electricity. Simultaneously, the mechanical spring energy storage mechanism, acting as a supplementary return-to-center driving force, forms a dual guarantee with the shape memory effect. Even if the vibration energy harvesting power is insufficient, the mechanical spring can still independently push the tie rod to return to center, further improving reliability under power outage conditions.

[0066] 8. This invention implements the steering function module using a steering actuation module and a tie rod module. The steering actuation module is located in the steering column or worm gear transmission mechanism, while the tie rod module connects the steering actuation module to the steering knuckle. This allows the magnetic field control and electric field control to cover the complete force transmission path from steering command input to wheel angle output. The steering actuation module is responsible for controlling response speed and torque accuracy, while the tie rod module is responsible for collision safety and power-off return-to-center protection. The two modules have clear division of labor and work together to achieve comprehensive safety control of the steering system across all operating conditions.

[0067] 9. This invention generates decision commands through a mode decision unit based on signals output by the state acquisition unit, driving status output by the onboard intelligent driving system, attitude information output by the vehicle attitude sensor, and prediction information output by the collision prediction sensor, thus achieving intelligent decision-making for steering safety control. The mode decision unit performs millisecond-level judgment and switching between normal driving situation, emergency obstacle avoidance situation, pre-collision situation, collision in progress situation, and power failure situation, upgrading the safety control of the steering system from a single-mode passive response to a multi-mode active adaptation, covering the full-condition safety requirements of the steer-by-wire system from normal driving to extreme failure.

[0068] 10. This invention achieves full-time coverage of steering safety control through the coordinated switching of five operating modes: normal driving mode, emergency obstacle avoidance mode, pre-collision triggering mode, in-collision protection mode, and power-off mode. The normal driving mode ensures comfort and stability during daily driving; the emergency obstacle avoidance mode ensures response speed and precision during extreme maneuvers; the pre-collision triggering mode ensures posture optimization and energy absorption in unavoidable collisions; the in-collision protection mode ensures structural integrity and wheel controllability during collision impacts; and the power-off mode ensures autonomous and safe return to center when the entire vehicle loses power. These five modes are interconnected in time and complementary in function, forming a complete safety chain from normal driving to emergency obstacle avoidance, from pre-collision to in-collision, and from power on to power off, overcoming the limitations of existing technologies that only focus on a single operating condition or a single safety objective. Attached Figure Description

[0069] Figure 1 This is a system connection block diagram of a steering safety control system and method for intelligent driving proposed in this invention;

[0070] Figure 2 This is a schematic diagram of the microstructure of a multiphase composite alloy material for a steering safety control system and method for intelligent driving proposed in this invention.

[0071] Figure 3 This is a flowchart of a steering safety control system and method for intelligent driving proposed in this invention. Detailed Implementation

[0072] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0073] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include," "contain," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "includes..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0074] refer to Figure 1-3 This invention provides a steering safety control system and method for intelligent driving, including a steering function module made of a multiphase composite alloy material and a field energy control module coupled to the steering function module. The steering function module is disposed in the steering transmission path of the steer-by-wire system. The multiphase composite alloy material changes its damping characteristics under the action of external field energy and can continuously change within a range of more than 10 times. Its geometry also changes under the action of external field energy. The field energy control module adjusts the damping characteristics and controls the geometry by applying adjustable field energy to the steering function module. Based on the above system, steering torque signals and vibration signals are collected by vibration sensing elements and / or strain sensing elements, temperature signals are collected by temperature sensing elements, and axial displacement signals of the tie rod are collected by displacement sensing elements. The state acquisition unit of the field energy control module receives the collected signals. The data is processed and output to the mode decision unit. The mode decision unit determines the safety situation based on the signal, vehicle driving status, and collision prediction information. When the collision time output by the collision prediction sensor is less than 300ms, it is determined to be a pre-collision situation. When the collision sensor detects that the acceleration exceeds a preset threshold, it is determined to be a collision in progress situation. When the field energy control module detects that the main power is cut off, it is determined to be a power failure situation. In other cases, it is determined to be a normal situation or an emergency obstacle avoidance situation based on the amplitude of the steering torque signal. The mode decision unit selects the target mode according to the determined safety situation and outputs the corresponding instructions to the magnetic field control unit and / or the thermal field control unit respectively. The normal situation corresponds to the normal driving mode, the emergency obstacle avoidance situation corresponds to the emergency obstacle avoidance mode, the pre-collision situation corresponds to the pre-collision trigger mode, the collision in progress situation corresponds to the collision protection mode, and the power failure situation corresponds to the power failure mode.

[0075] Preparation of multiphase composite alloy materials:

[0076] The multiphase composite alloy material of the present invention is prepared by means of the following steps:

[0077] (a) Raw material preparation:

[0078] The matrix material is a near-equal atomic ratio Ni-Ti alloy powder, wherein the Ni content is 50.0 at% to 50.8 at% and the Ti content is 49.2 at% to 50.0 at%. The alloy powder is prepared by gas atomization and the powder particle size is 10 μm to 50 μm.

[0079] Preparation of magnetorheological elastomer microparticles: Two-component room temperature vulcanizing silicone rubber was mixed with micron-sized carbonyl iron powder at a mass ratio of 100:200 to 100:400, wherein the carbonyl iron powder had a particle size of 1 μm to 5 μm. After uniform mixing, the mixture was cured under a pre-applied magnetic field of 0 mT to 700 mT. The cured magnetorheological elastomer was mechanically crushed and sieved to obtain microparticles with a particle size of 10 μm to 50 μm.

[0080] (II) Mixing and Sintering:

[0081] Ni-Ti alloy powder and magnetorheological elastomer microparticles are uniformly mixed at a volume ratio of 85:15 to 95:5, so that the volume fraction of the magnetorheological elastomer microparticles is 5% to 15%. The mixing is carried out in a V-type mixer at a speed of 20 rpm to 40 rpm for 2 to 4 hours.

[0082] The mixed powder is packed into a casing and sintered under inert gas protection using hot isostatic pressing. The sintering temperature is 900℃ to 1100℃, the pressure is 100MPa to 200MPa, and the holding time is 2 hours to 4 hours.

[0083] (III) Heat treatment:

[0084] The sintered billet was solution treated at 850℃ for 1 hour, followed by water quenching. Then, it underwent aging treatment at 500℃ for 4 hours, followed by air cooling. Through solution and aging treatments, the martensitic transformation temperature of the Ni-Ti alloy matrix was controlled to the range of -20℃ to 80℃.

[0085] (iv) Surface coating:

[0086] A combined electroplating and electroless plating process was used to sequentially deposit an inner layer and an outer layer on the surface of the heat-treated material. The inner layer, a Ni-Fe alloy layer, was deposited by electroplating at a bath temperature of 50°C to 60°C, a current density of 2A / dm² to 5A / dm², and a deposition time of 30 to 60 minutes, resulting in a Ni-Fe alloy layer with a thickness of 10 μm to 20 μm. The outer layer, a Cu layer, was deposited by electroless plating at a bath temperature of 40°C to 50°C and a deposition time of 20 to 40 minutes, resulting in a Cu layer with a thickness of 5 μm to 10 μm.

[0087] (v) Molding and processing:

[0088] The coated material is then machined into the desired component shape, including tie rods and moving parts of steering actuators.

[0089] The specific structure of the system:

[0090] The steering safety control system of the present invention includes a steering function module and a field energy regulation module. The steering function module includes a steering execution module and a tie rod module.

[0091] (a) The specific structure of the steering execution module:

[0092] The steering actuation module is located in the steering column or worm gear transmission mechanism of the steer-by-wire system. The steering actuation module includes a moving part made of multiphase composite alloy material, as well as a housing, excitation coil, heating element, temperature sensing element, vibration sensing element, and strain sensing element.

[0093] The housing is made of aluminum alloy and has a cylindrical cavity inside. The moving parts are located inside the cavity and are connected to the steering input shaft or steering output shaft via splines or keys.

[0094] The excitation coil is wound around the periphery of the receiving cavity, with 200 to 500 turns, and the coil frame is made of non-magnetic material. The excitation coil is coupled to the magnetic field control unit of the field energy control module via a wire.

[0095] The heating element is embedded inside the moving part. The heating element is a resistance wire made of nickel-chromium alloy, with a rated power of 50W to 200W. The heating element is coupled to the thermal field control unit of the field energy control module via a wire.

[0096] The temperature sensing element is set on the surface of the moving part, and a K-type thermocouple is used. The temperature measurement range is -40℃ to 150℃. It is coupled to the state acquisition unit of the field energy control module through a signal line.

[0097] Vibration sensing elements and strain sensing elements are located inside the moving parts. The vibration sensing element is a piezoelectric accelerometer, and the strain sensing element is a resistance strain gauge. They are coupled to the state acquisition unit of the field energy control module through signal lines.

[0098] (II) Specific structure of the tie rod module:

[0099] The tie rod module connects the steering actuator module to the steering knuckle. The tie rod module includes a rod body made of multiphase composite alloy material, as well as an excitation coil sleeve, a heating element, a displacement sensing element, a rectifier energy storage unit, and a mechanical energy storage unit.

[0100] The tie rod body is integrally formed from multiphase composite alloy material, and ball joint pin connection holes are provided at both ends of the rod body, which are respectively connected to the steering actuator module and the steering knuckle.

[0101] The excitation coil bushing is fitted onto the outside of the tie rod body, and the excitation coil is embedded in the bushing wall, with 150 to 400 turns. The excitation coil bushing is coupled to the magnetic field control unit of the field energy control module via a wire.

[0102] The heating element is embedded inside the tie rod and extends along its axial direction. The heating element is a resistance wire made of nickel-chromium alloy, with a rated power of 30W to 100W. The heating element is coupled to the thermal field control unit of the field energy control module via a wire.

[0103] Displacement sensing elements are located at both ends of the tie rod. These elements are linear displacement sensors with a measurement range of 0mm to 50mm and an accuracy of ±0.1mm. The displacement sensing elements are coupled to the status acquisition unit of the field energy control module via a signal line.

[0104] The rectifier energy storage unit is located at one end of the horizontal tie rod. It includes a rectifier bridge, a filter capacitor, and an energy storage capacitor. The rectifier bridge is a full-bridge rectifier circuit composed of four Schottky diodes. The filter capacitor is an electrolytic capacitor with a capacitance ranging from 100μF to 1000μF. The energy storage capacitor is a supercapacitor with a capacitance ranging from 1F to 10F and a withstand voltage of 5.5V. The rectifier energy storage unit is coupled to the heating element via a wire.

[0105] The mechanical energy storage unit includes a compression spring and an electromagnet. When the field energy regulation module is energized, the compression spring is held in a compressed state by the electromagnet. In the power-off mode, the electromagnet releases the compression spring, and the elastic potential energy of the compression spring pushes the tie rod to move towards the straight-line travel position.

[0106] (III) Specific structure of the field energy regulation module:

[0107] The field energy regulation module is coupled with the steering function module. The field energy regulation module includes a magnetic field regulation unit, a thermal field regulation unit, a state acquisition unit, a mode decision-making unit, and an energy storage management unit.

[0108] The magnetic field control unit is coupled to the excitation coil via a wire. The magnetic field control unit is an adjustable DC power supply with an output current range of 0A to 10A and an output voltage range of 0V to 48V. The magnetic field control unit receives the first command output by the mode decision unit and outputs the corresponding adjustable current to the excitation coil.

[0109] The thermal field control unit is coupled to the heating element via a wire. The thermal field control unit is an adjustable DC power supply with an output current range of 0A to 5A and an output voltage range of 0V to 24V. The thermal field control unit receives a second command from the mode decision unit and outputs a corresponding adjustable current to the heating element.

[0110] The status acquisition unit is coupled to the temperature sensing element, vibration sensing element, strain sensing element, and displacement sensing element via signal lines. The status acquisition unit includes a signal conditioning circuit and an analog-to-digital conversion circuit. The analog-to-digital conversion circuit has a resolution of 12 bits to 16 bits and converts the acquired analog signal into a digital signal before outputting it to the mode decision unit.

[0111] The mode decision unit is coupled to the magnetic field control unit, thermal field control unit, state acquisition unit, in-vehicle intelligent driving system, vehicle attitude sensor, and collision prediction sensor via a CAN bus and dedicated signal line. The mode decision unit is an embedded microcontroller that internally stores the mode decision program. Based on the signals output by the state acquisition unit, the driving state output by the in-vehicle intelligent driving system, the attitude information output by the vehicle attitude sensor, and the prediction information output by the collision prediction sensor, the mode decision unit generates decision commands and outputs a first command to the magnetic field control unit and a second command to the thermal field control unit.

[0112] The energy storage management unit is coupled to the rectifier energy storage unit via a wire. The energy storage management unit includes a voltage monitoring circuit and a discharge control circuit, which are used to monitor the energy storage status of the rectifier energy storage unit and output an energy release signal to the thermal field control unit in power-off mode.

[0113] Example 1

[0114] Purpose of implementation:

[0115] The present invention verifies that, in normal driving mode, the steering safety control system applies a magnetic field through the field energy regulation module to cause the multiphase composite alloy material to generate adaptive damping, thereby filtering out high-frequency road vibrations and improving steering comfort and handling stability.

[0116] Implementation System:

[0117] The steering safety control system is configured as follows:

[0118] The multiphase composite alloy material is composed of: a Ni-Ti alloy matrix with a Ni content of 50.2 at% and a Ti content of 49.8 at% and a martensitic phase transformation temperature of Ms = 45℃; a magnetorheological elastomer microparticle volume fraction of 10%; carbonyl iron powder with a particle size of 3 μm; a silicone rubber to carbonyl iron powder mass ratio of 100:300; and is cured under a pre-applied magnetic field of 300 mT; the surface coating consists of an inner Ni-Fe alloy layer of 15 μm and an outer Cu layer of 8 μm.

[0119] The steering actuation module includes a moving component made of the aforementioned multiphase composite alloy material and is housed in the steering column of the steer-by-wire system. The tie rod module includes a rod made of the aforementioned multiphase composite alloy material and connects the steering actuation module to the steering knuckle. The field energy regulation module is coupled to both the steering actuation module and the tie rod module and is used to apply an adjustable magnetic field to the multiphase composite alloy material.

[0120] The above system was installed in the steer-by-wire system of a certain B-class passenger vehicle.

[0121] Implementation steps:

[0122] S1. Steering torque and vibration signals are collected through vibration sensing elements, temperature signals are collected through temperature sensing elements, and axial displacement signals of the tie rod are collected through displacement sensing elements.

[0123] S2. The state acquisition unit of the field energy regulation module receives the signal collected in step S1, processes it, and outputs it to the mode decision unit. The mode decision unit determines that the current driving situation is normal based on the signal output by the state acquisition unit—steering torque amplitude less than 1 N·m, vibration acceleration amplitude less than 0.5 m / s², vehicle speed 60 km / h—and the normal driving status output by the on-board intelligent driving system.

[0124] S3. The mode decision unit selects the normal driving mode based on the normal driving situation determined in step S2, and outputs a first command with a current setting value of 2.5A to the magnetic field control unit.

[0125] After receiving the first command from the mode decision unit, the magnetic field control unit outputs an adjustable current of 2.5A to the excitation coil. The magnetic field strength generated by the excitation coil is 200mT, which causes the magnetorheological elastomer particles in the multiphase composite alloy material to produce a moderate damping effect, increasing the equivalent damping coefficient of the steering system to 8 times that in the absence of a magnetic field. The Ni-Ti alloy matrix remains in the austenitic state at a temperature of 25℃, which is lower than the martensitic phase transformation temperature of 45℃, providing a structural stiffness of 75GPa.

[0126] Implementation results:

[0127] The vibration energy generated by high-frequency road bumps is dissipated by the viscoelastic damping of magnetorheological elastomer particles, reducing the vibration frequency range from 50Hz to 200Hz and lowering the high-frequency vibration amplitude of the steering wheels by 65%. The peak-to-peak value of steering wheel torque fluctuation decreased from 2.5 N·m before modification to 0.9 N·m, a reduction of 64%. The resonant frequency of the steering system decreased from 12Hz to 8Hz, effectively avoiding the upper limit of the human body's sensitive frequency range of 4Hz to 8Hz. With the continuous operation of the surface Ni-Fe / Cu composite coating, the signal-to-noise ratio of the steering ECU signal harness remains above 40dB under electromagnetic field interference of 200V / m.

[0128] The above results show that, under normal driving mode, the field energy control module applies an adjustable magnetic field to change the damping coefficient of the multiphase composite alloy material, thereby achieving adaptive adjustment of the equivalent damping of the steering system and effectively filtering out high-frequency road vibrations.

[0129] Example 2

[0130] Purpose of implementation:

[0131] The present invention verifies that, in emergency obstacle avoidance mode, the steering safety control system reduces the magnetic field and applies an electric field to heat the multiphase composite alloy material through the field energy regulation module, thereby reducing the equivalent rotational inertia of the moving parts of the steering actuator module and improving the steering response speed.

[0132] Implementation System:

[0133] The same vehicle and material configuration as in Example 1 were used. The multiphase composite alloy material had the following composition: Ni content 50.2 at%, Ti content 49.8 at%, martensitic phase transformation temperature Ms = 45°C, and magnetorheological elastomer particle volume fraction 10%.

[0134] Implementation steps:

[0135] S1. Steering torque and vibration signals are acquired through vibration sensing elements and strain sensing elements, and temperature signals are acquired through temperature sensing elements.

[0136] S2. The mode decision unit receives the emergency obstacle avoidance command output by the vehicle intelligent driving system via the CAN bus—a stationary obstacle appears 50m ahead, the collision time TTC=2.25 seconds, and the vehicle speed is 80km / h—combined with the signals of a sudden increase in steering torque amplitude and an increase in vibration acceleration amplitude output by the status acquisition unit, and determines that the current situation is an emergency obstacle avoidance situation.

[0137] S3. The mode decision unit selects the emergency obstacle avoidance mode based on the emergency obstacle avoidance situation determined in step S2, and performs the following operations:

[0138] The mode decision unit outputs a first instruction with a current setting value of 0A to the magnetic field control unit. After receiving the first instruction, the magnetic field control unit cuts off the current of the excitation coil, so that the damping of the magnetorheological elastomer particles is reduced to 1.2 times the reference value without magnetic field within 1ms.

[0139] The mode decision unit outputs a second command to the thermal field control unit, with a current setting value of 50A and a duration of 100ms. After receiving the second command, the thermal field control unit applies a pulse current with a duration of 100ms to the multiphase composite alloy material through the heating element. The Joule heating effect causes the temperature of the alloy matrix to rise from 25℃ to 60℃ within 80ms, exceeding the martensitic transformation temperature of 45℃. The Ni-Ti alloy matrix undergoes a reverse martensitic transformation, and the elastic modulus decreases from 75GPa to 52GPa, a decrease of 30.7%.

[0140] After heating for 100ms and then cutting off the current, the reduced elastic modulus of the Ni-Ti alloy matrix can be maintained for about 500ms under natural cooling conditions, which is the time it takes for the temperature to drop from 60℃ to 45℃. This is sufficient to cover the time interval from the end of heating to the time when the intelligent driving system issues a steering command.

[0141] The intelligent driving system issues a steering command at TTC=1.8 seconds, with a target steering angle of 30° and a steering angular velocity of 300° / s. At this time, approximately 350ms have passed since the end of heating, and the alloy matrix temperature is approximately 48°C, still in a low elastic modulus state.

[0142] Implementation results:

[0143] The equivalent moment of inertia of the moving parts in the steering actuation module was reduced from 0.025 kg·m² to 0.011 kg·m², a decrease of 56%. The steering wheel response delay was shortened from 85 ms in the normal mode to 28 ms. The steering actuation module began to respond to the steering commands of the intelligent driving system after 28 ms, and completed the output of a 30° steering angle within 620 ms, enabling the vehicle to successfully avoid obstacles.

[0144] Compared to the control test that did not use the emergency obstacle avoidance mode of this invention, the response delay was 85ms, the completion time was 780ms, and the lateral displacement required for obstacle avoidance was reduced by 1.2m.

[0145] The above results show that, in emergency obstacle avoidance mode, the field energy regulation module reduces the equivalent moment of inertia of the moving parts of the steering actuator module by more than 50% by reducing the magnetic field and applying an electric field to heat the multiphase composite alloy material, thus significantly improving the steering response speed.

[0146] Example 3

[0147] Purpose of implementation:

[0148] The present invention verifies that the steering safety control system, in the pre-collision trigger mode, applies a pulsed electric field through the field energy regulation module to excite the shape memory effect of the multiphase composite alloy material, causing the tie rod module to produce a preset stroke of active extension and contraction deformation to optimize the collision posture.

[0149] Implementation System:

[0150] The same vehicle and material configuration as in Example 1 were used. The collision prediction sensor was a lidar mounted on the front bumper of the vehicle, with a detection range of 150m and a coverage area of ​​120° in front. The vehicle attitude sensor was mounted at the vehicle's center of gravity to output vehicle yaw and roll angle information.

[0151] Implementation steps:

[0152] S1. Steering torque and vibration signals are collected through vibration sensing elements, temperature signals are collected through temperature sensing elements, and axial displacement signals of the tie rod are collected through displacement sensing elements.

[0153] S2. The mode decision unit receives the collision prediction signal output by the collision prediction sensor through a dedicated signal line—the estimated collision time TTC is 180ms, the estimated collision angle is 30° to the right front, and the road surface wet adhesion coefficient is 0.4—combined with the information of yaw angle 0° and roll angle 0° output by the vehicle attitude sensor, and determines that the current situation is a pre-collision situation.

[0154] S3. The mode decision unit selects the pre-collision trigger mode based on the pre-collision situation determined in step S2, and performs the following operations:

[0155] Based on the expected collision time of 180ms and the expected collision angle of 30° to the right front, the mode decision unit calculates the required active extension and direction of the tie rod. The calculation result is: the right front wheel toe angle needs to change outward by 2°, corresponding to an extension of 12mm in the tie rod.

[0156] The mode decision unit outputs a second command of a pulsed current sequence to the thermal field control unit, with a frequency of 10Hz, a duty cycle of 50%, and a peak current of 40A. Upon receiving the second command, the thermal field control unit applies a pulsed current with a frequency of 10Hz and a duty cycle of 50% to the heating element inside the tie rod. During the first pulse cycle, the tie rod temperature rises from 25℃ to 55℃, exceeding the martensitic transformation temperature of 45℃. The Ni-Ti alloy matrix undergoes a reverse martensitic transformation, the shape memory effect is activated, and the tie rod undergoes axial elongation deformation.

[0157] The displacement sensing element monitors the axial displacement of the tie rod in real time. When the elongation reaches 12mm, the mode decision unit cuts off the heating current, and the tie rod stops elongating. The right front wheel toe angle changes outward by 2.1°.

[0158] Implementation results:

[0159] The vehicle completed active toe adjustment before the collision, at which point TTC=95ms. Upon impact, the vehicle adopted a predetermined sideslip posture to meet the impact, and the lateral friction between the tires and the road surface effectively dissipated 18% of the collision energy. Measurements from the vehicle's acceleration sensors showed that the peak acceleration decreased from 28g without active toe adjustment to 23g, and passenger compartment intrusion was reduced by 15%.

[0160] After the collision, the mode decision unit determined that the collision had ended based on the peak acceleration signal of 23g lasting 80ms detected by the collision sensor, and switched to the normal driving mode. During the natural cooling process of the tie rod body at an ambient temperature of 25°C, the temperature gradually decreased to below the martensitic transformation temperature of 45°C. The Ni-Ti alloy underwent a martensitic transformation, and the tie rod body returned to its original length in 8 seconds, with the toe angle returning to normal.

[0161] The above results show that, in the pre-collision trigger mode, the field energy control module excites the shape memory effect of the Ni-Ti alloy matrix by applying a pulsed electric field, which causes the crossbar module to generate active extension and contraction deformation of a preset stroke within milliseconds, effectively optimizing the collision attitude and reducing collision damage.

[0162] Example 4

[0163] Purpose of implementation:

[0164] The present invention verifies that the steering safety control system in the collision protection mode releases electrical energy from the energy storage element through the field energy regulation module to apply an instantaneous strong magnetic field, causing the magnetorheological elastomer particles to reach a magnetic saturation state, thereby switching the tie rod module to a restricted state to prevent the steering wheel from losing control and swaying.

[0165] Implementation System:

[0166] The same vehicle and material configuration as in Example 1 were used. The collision sensor was an acceleration sensor, mounted on the front longitudinal beam of the vehicle. The energy storage capacitor stored 50J of energy and operated at 48V.

[0167] The trigger threshold for the collision protection mode is set at 50g. This threshold is determined based on the vehicle's airbag trigger threshold of 30g to 80g and the structural strength design of the steering system. This avoids false triggering under non-collision conditions such as road bumps, while ensuring timely intervention when the collision impact is sufficient to threaten the structural safety of the steering system.

[0168] Implementation steps:

[0169] S1. Steering torque and vibration signals are acquired through vibration sensing elements and strain sensing elements, and temperature signals are acquired through temperature sensing elements.

[0170] S2. The mode decision unit receives the prediction signal (TTC=150ms) output by the collision prediction sensor via a dedicated signal line, determines it to be a pre-collision situation, and executes the pre-collision trigger mode to actively retract the tie rod by 5mm. Subsequently, the collision sensor detects an acceleration signal of 55g, which exceeds the preset threshold of 50g, and the mode decision unit determines that the current situation is a collision in progress.

[0171] S3. The mode decision unit selects the protection mode in the collision based on the collision determination in step S2, and performs the following operations:

[0172] The mode decision unit outputs a hard lockout command to the energy storage control unit. After receiving the command, the energy storage control unit blows the fuse of the excitation coil in less than 1ms, releasing all the electrical energy (50J, 48V) stored in the energy storage capacitor.

[0173] The discharge of the energy storage capacitor generates a transient strong magnetic field with a magnetic induction intensity of 800 mT and a duration of 5 ms, causing the magnetorheological elastomer particles inside the multiphase composite alloy material to instantly reach a magnetic saturation state. The carbonyl iron powder particles align into a chain-like structure along the direction of the magnetic field, and the shear modulus of the magnetorheological elastomer increases sharply.

[0174] The equivalent damping coefficient of the tie rod module increases sharply from the normal value of 2.5 kN·s / m to 22 times the normal value, i.e., 55 kN·s / m, within 3 ms, and the tie rod body switches to a restricted state.

[0175] Displacement sensing elements monitor the axial displacement of the tie rod in real time.

[0176] Implementation results:

[0177] Displacement sensing showed that the axial displacement of the tie rod was limited to within +0.3mm to -0.4mm. When a peak impact force of 45kN was applied to the steering tie rod, no axial collapse occurred and the steering wheels did not wobble uncontrollably because the tie rod was in a restricted state. Post-impact inspection revealed no plastic deformation in the tie rod, and the steering system functioned normally.

[0178] The control vehicle, which did not use the collision protection mode, experienced axial collapse of 8mm in the tie rod and yaw of 6° in the same collision conditions, and yawed 15° to the right after the collision.

[0179] The above results show that, in the collision protection mode, the field energy regulation module applies an instantaneous strong magnetic field to the multiphase composite alloy material by releasing the electrical energy of the energy storage element, so that the magnetorheological elastomer particles reach the magnetic saturation state, and the tie rod module switches to the restricted state, effectively preventing the steering wheel from losing control and swaying under the impact of the collision.

[0180] Example 5

[0181] Purpose of implementation:

[0182] The present invention verifies that in the power-off mode, the tie rod module uses road vibration energy to generate electrical energy through magnetostriction, which is then rectified and stored before being released to the heating element to excite the shape memory effect, thereby restoring the steering wheel to the straight driving position.

[0183] Implementation System:

[0184] The same vehicle and material configuration as in Example 1 are used. The output power of the rectifier energy storage unit is 50mW to 500mW, the starting power of the heating element is 100mW to 1000mW, and the energy storage capacitor has an energy storage capacity of 50J. The tie rod module is equipped with a mechanical energy storage unit, including a compression spring and an electromagnet.

[0185] Implementation steps:

[0186] S1. During vehicle operation, vibration signals are collected through vibration sensing elements, and axial displacement signals of the tie rod are collected through displacement sensing elements.

[0187] S2. The field energy control module detects a power outage, with the voltage dropping to 0V. The mode decision unit determines that the current situation is a power outage. At this time, the steering wheel is at a yaw angle of approximately 3°. This yaw angle is the working position of the steering wheel at the moment of power outage, and is determined by factors such as the road cross slope and the lateral force on the steering wheel at the moment of power outage. It is a random yaw state.

[0188] S3. The mode decision unit selects the power failure mode based on the power failure situation determined in step S2, and the system enters the passive working state:

[0189] Vibrations of 15Hz to 30Hz frequency and 2mm to 4mm amplitude caused by road bumps are transmitted to the tie rod through the steering column. Under vibration stress, the multiphase composite alloy material of the tie rod module exhibits magnetostriction, generating an alternating induced electromotive force within the material. Induction coils at both ends of the tie rod output an alternating induced current with an amplitude of 5mA to 20mA and a frequency matching the vibration frequency. The rectifier energy storage unit rectifies the alternating induced current and stores it in an energy storage capacitor.

[0190] The energy storage management unit monitors the voltage of the energy storage capacitor. When the voltage reaches 5V, approximately at the 45th second, the energy storage management unit outputs an energy release signal to the thermal field control unit. The energy storage capacitor releases electrical energy to the heating element through the discharge control circuit, with a release power of 200mW, lasting for 2 seconds. The heating element intermittently heats the tie rod, causing a local temperature increase of 15°C.

[0191] Under the influence of a temperature increase from 25°C to 40°C and a martensitic phase transformation, the Ni-Ti alloy matrix causes the tie rod to shrink at a rate of 0.1 mm / s. Simultaneously, the compression spring of the mechanical energy storage unit is released by the electromagnet when the power is off, and the elastic potential energy propels the tie rod to move towards the straight-line travel position.

[0192] The displacement sensing element is powered by an energy storage capacitor with a power consumption of 5mW and monitors the axial displacement of the tie rod. When the tie rod returns to the straight driving position, that is, when the steering angle of both the left and right front wheels is 0°, the energy storage control unit stops discharging.

[0193] Implementation results:

[0194] Without initial energy storage, under continuous vibration with an amplitude of 1mm to 5mm, the rectifier energy storage unit established a 5V operating voltage within 38 seconds and restored the steering wheel from a 3° yaw angle to a straight-line driving position of 0° within 95 seconds. The tie rod completed the power-off return to centering process under the combined action of shape memory effect and mechanical spring energy storage mechanism. The vehicle maintained straight-line driving until a safe stop.

[0195] In the control vehicle that did not adopt the present invention, the steer-by-wire system completely failed under the same power failure condition. The steering wheel remained at a 5° yaw angle at the moment of power failure and could not return to center. The vehicle deviated from the lane and ran off the shoulder within 150m.

[0196] The above results demonstrate that, in power-off mode, the tie rod module utilizes road vibration energy to generate an induced current through magnetostriction. After rectification and energy storage, this current is released to the heating element, stimulating the shape memory effect and restoring the steering wheels to a straight-line driving position. Simultaneously, the mechanical energy storage unit provides redundant return-to-center driving force, achieving autonomous and safe return-to-center operation without relying on an external power source.

[0197] Comparative Example 1

[0198] This comparative example uses a steer-by-wire system from a mass-produced passenger vehicle of a certain brand to illustrate the superiority of the present invention over the prior art.

[0199] The proportional system is configured as follows: the steering actuator uses 45# steel components with an elastic modulus of 210 GPa; the steering tie rod is made of Q235 steel; steering damping is achieved through an electronically controlled hydraulic damper with a fixed damping coefficient of 2.0 kN·s / m. This system has only a single operating mode and lacks mode switching functionality; the steering wheels cannot return to center after a power outage; the tie rod components lack active deformation capability; and there is no restricted state switching function during a collision.

[0200] The above comparative system was installed on the same vehicle platform as in Examples 1 to 5 and tested under the same operating conditions as in each example. Only the system response results were recorded, and no control strategy of the present invention was executed.

[0201] The effects of implementing the comparative model are as follows:

[0202] Under normal driving conditions, the steering system of the comparative vehicle relies on a hydraulic damper to provide fixed damping, which cannot be adjusted according to road conditions. Vibrations generated by high-frequency road bumps are directly transmitted to the steering wheel, with the peak-to-peak value of steering wheel torque fluctuation reaching 2.8 N·m. In contrast, the peak-to-peak value of steering wheel torque fluctuation in Embodiment 1 of this invention is 0.9 N·m, a reduction of 68% compared to the comparative vehicle.

[0203] In emergency obstacle avoidance conditions, the comparative vehicle's steering actuator moment of inertia is 0.032 kg·m², and the steering wheel response delay is 92 ms. The comparative vehicle issues a steering command at TTC=1.8 seconds, requiring 810 ms to complete a 30° steering angle output, and the lateral displacement required for obstacle avoidance is 1.5 m greater than that of Embodiment 2 of this invention. In contrast, Embodiment 2 of this invention has an equivalent moment of inertia of 0.011 kg·m², a response delay of 28 ms, and completes the steering angle output in only 620 ms.

[0204] Under pre-collision triggering conditions, the steering tie rod of the comparative vehicle is made of ordinary carbon steel, which does not possess shape memory effect and cannot actively change the front wheel toe angle before the collision. Under the same collision conditions, the comparative vehicle faces the collision head-on, with a peak acceleration of 30g, and the passenger compartment intrusion is 22% greater than that of Embodiment 3 of the present invention. After the collision, the steering tie rod of the comparative vehicle undergoes 5mm of irreversible plastic bending deformation and needs to be replaced before it can continue to be driven. In contrast, the peak acceleration of Embodiment 3 of the present invention is 23g, the passenger compartment intrusion is reduced by 15%, and the tie rod can recover on its own after natural cooling after the collision, without the need for replacement.

[0205] In the collision protection scenario, the tie rod of the comparative vehicle lacks the function of switching to a restricted state. The impact force of the collision causes the tie rod to collapse axially by 12mm, the steering wheel to wobble by 8°, and the vehicle to yaw 15° to the right after the collision. However, the tie rod of Embodiment 4 of the present invention switches to a restricted state during the collision, with an axial displacement of no more than ±0.5mm, and the steering wheel does not wobble out of control.

[0206] In the event of a power outage, the steer-by-wire system of the comparative vehicle completely fails, and the steering wheels remain at a 5° yaw angle at the moment of power failure and cannot return to the correct position. The vehicle deviates from the lane and runs off the curb within 150 meters. However, the tie rod of Embodiment 5 of this invention utilizes the energy from road vibration and the energy stored in the mechanical spring to restore the steering wheels to the straight driving position within 95 seconds after a power outage.

[0207] Based on the comparison results of the five operating conditions above: the peak-to-peak value of steering wheel vibration of the comparative vehicle during normal driving was 2.8 N·m, while that of this invention was reduced to 0.9 N·m; the emergency obstacle avoidance response delay of the comparative vehicle was 92 ms, while that of this invention was shortened to 28 ms; the emergency obstacle avoidance completion time of the comparative vehicle was 810 ms, while that of this invention was shortened to 620 ms; the peak collision acceleration of the comparative vehicle was 30g, while that of this invention was reduced to 23g; the tie rod of the comparative vehicle underwent 5 mm of plastic deformation after a collision and needed to be replaced, while that of this invention can recover on its own and does not require replacement; the steering wheel yaw angle of the comparative vehicle after a collision was 8°, while that of this invention is controlled within 0.5°; the comparative vehicle had no self-centering ability after power failure, while that of this invention can complete self-centering within 95 seconds.

[0208] The above comparison results fully demonstrate that the present invention has achieved significant and unexpected technical effects in the full-condition safety management of the online steering system by using multiphase composite alloy materials to construct the steering actuation module and tie rod module, and combining them with multi-mode collaborative control of the field energy regulation module.

[0209] Summary of technical effects:

[0210] Based on the verification results of embodiments 1 to 5 above, the system described in this invention has achieved the design expectations in all operating modes:

[0211] In normal driving mode, the field energy control module applies a magnetic field to induce adaptive damping in the magnetorheological elastomer particles, reducing steering wheel torque fluctuations by 64% and effectively filtering out high-frequency road vibrations, thus improving driving comfort. This mode verifies the feasibility of applying an adjustable magnetic field through the field energy control module to vary the damping characteristics of multiphase composite alloy materials within a continuous range.

[0212] In the emergency obstacle avoidance mode, the field energy regulation module reduces the magnetic field and applies an electric field for heating, thereby reducing the equivalent moment of inertia of the moving parts of the steering actuator module by 56% and shortening the steering response delay to 28ms, thus gaining valuable time for extreme obstacle avoidance. This mode verifies the feasibility of the field energy regulation module reducing the equivalent moment of inertia of moving parts by more than 50% by reducing the magnetic field and applying an electric field.

[0213] In the pre-collision trigger mode, a pulsed electric field is applied by the field energy control module to excite the shape memory effect of the Ni-Ti alloy matrix, causing the tie rod to undergo a 12mm active telescopic deformation within 85ms, reducing the peak collision acceleration by 23%. This mode verifies the feasibility of the field energy control module inducing a preset telescopic deformation of the tie rod by applying a pulsed electric field to excite the shape memory effect.

[0214] In the collision protection mode, the field energy control module releases stored electrical energy to apply a momentary strong magnetic field, causing the magnetorheological elastomer particles to reach magnetic saturation. This causes the equivalent damping coefficient of the tie rod module to surge to 22 times its normal value, limiting axial displacement to within ±0.5 mm. This mode verifies the feasibility of the field energy control module applying a magnetic field by releasing stored electrical energy to switch the tie rod module to a restricted state.

[0215] In power-off mode, the tie rod module utilizes road vibration energy to generate an induced current through magnetostriction. After rectification and energy storage, this current is released to the heating element to excite the shape memory effect, completing the steering wheel return to center within 95 seconds. The mechanical energy storage unit provides redundant return-to-center driving force. This mode verifies the feasibility of the tie rod module using external vibration energy to generate electrical energy to excite the shape memory effect and restore the steering wheel to a straight-line driving position.

[0216] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.

[0217] In conclusion, the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A steering safety control system for intelligent driving, characterized in that, include: The steering function module is made of multiphase composite alloy material. The damping characteristics of the multiphase composite alloy material change under the action of external field energy, and its geometric shape changes under the action of external field energy. The field energy regulation module is coupled to the steering function module and is used to apply adjustable field energy to the steering function module; The steering function module is located in the steering transmission path of the steer-by-wire system; The field energy control module applies the adjustable field energy to continuously change the damping characteristics of the multiphase composite alloy material within a range of more than 10 times, and applies the adjustable field energy to cause deformation of the multiphase composite alloy material.

2. The intelligent driving steering safety control system as described in claim 1, characterized in that, The multiphase composite alloy material uses Ni-Ti shape memory alloy as a matrix, and magnetorheological elastomer particles are distributed in the matrix. The field energy control module applies a magnetic field and / or an electric field to the multiphase composite alloy material, causing the system to switch between at least two of the following modes: In the first mode, the field energy control module applies a first magnetic field to the multiphase composite alloy material, causing the magnetorheological elastomer particles to generate a first damping. In the second mode, the field energy regulation module reduces or cuts off the first magnetic field and applies an electric field, thereby reducing the elastic modulus of the Ni-Ti alloy matrix and reducing the equivalent rotational inertia of the steering function module. In the third mode, the field energy control module applies a pulsed electric field to excite the shape memory effect of the Ni-Ti alloy matrix, causing the steering function module to deform. In the fourth mode, the field energy regulation module releases electrical energy from the energy storage element to apply a second magnetic field to the multiphase composite alloy material. The strength of the second magnetic field is greater than that of the first magnetic field, causing the magnetorheological elastomer particles to reach a magnetic saturation state, and the steering function module switches to a restricted state. In the fifth mode, the steering function module uses external vibration energy to generate electrical energy to stimulate the shape memory effect, causing the steering function module to return to a preset position.

3. The intelligent driving steering safety control system as described in claim 2, characterized in that, When the steering function module is a tie rod, the deformation of the tie rod in the third mode is axial extension and contraction with a stroke of 5mm to 20mm, and the axial displacement does not exceed ±0.5mm when switching to the restricted state in the fourth mode; when the steering function module is the rotor or piston of the steering actuator, the equivalent rotational inertia of the rotor or piston in the second mode is reduced by more than 50%.

4. The intelligent driving steering safety control system as described in claim 1, characterized in that, The steering function module includes: A steering actuation module, disposed in the steering column or worm gear transmission mechanism of the steer-by-wire system, the steering actuation module comprising a moving component made of the multiphase composite alloy material; and A tie rod module connects the steering actuation module and the steering knuckle, the tie rod module comprising a rod body made of the multiphase composite alloy material; The field energy regulation module is coupled to the steering execution module and the tie rod module respectively; A protective housing covers the outside of the field energy regulation module; The multiphase composite alloy material uses Ni-Ti alloy as the matrix, and magnetorheological elastomer particles are distributed in the matrix. The surface of the matrix is ​​coated. The field energy control module controls the magnetic field and / or electric field applied to the multiphase composite alloy material, enabling the system to switch between normal driving mode, emergency obstacle avoidance mode, pre-collision triggering mode, collision protection mode and power failure mode. In the normal driving mode, the field energy control module applies a magnetic field to the multiphase composite alloy material, causing the magnetorheological elastomer particles to generate damping. In the emergency obstacle avoidance mode, the field energy control module reduces the magnetic field and applies an electric field to heat the multiphase composite alloy material, thereby reducing the equivalent moment of inertia of the multiphase composite alloy material. In the pre-collision trigger mode, the field energy control module applies a pulsed electric field to the crossbar module to excite the shape memory effect of the Ni-Ti alloy matrix, causing the rod to undergo expansion and contraction deformation. In the collision protection mode, the field energy regulation module releases electrical energy from the energy storage element to apply a magnetic field to the multiphase composite alloy material, causing the magnetorheological elastomer particles to reach magnetic saturation, and the horizontal tie rod module switches to a confined state; and In the power-off mode, the tie rod module uses road vibration energy to generate electrical energy, which is then rectified, stored, and released to the heating element to activate the shape memory effect, causing the steering wheel to return to the straight driving position.

5. The intelligent driving steering safety control system as described in claim 4, characterized in that, In the multiphase composite alloy material: The Ni-Ti alloy has a Ni content of 50.0 at% to 50.8 at%, a Ti content of 49.2 at% to 50.0 at%, and a martensitic transformation temperature of -20°C to 80°C. The magnetorheological elastomer microparticles have a particle size of 10 μm to 50 μm and a volume fraction of 5% to 15%. The coating comprises an inner layer and an outer layer, wherein the inner layer is a Ni-Fe alloy layer with a thickness of 10 μm to 20 μm, and the outer layer is a Cu layer with a thickness of 5 μm to 10 μm; The magnetorheological elastomer is composed of a two-component room temperature vulcanizing silicone rubber and carbonyl iron powder. The particle size of the carbonyl iron powder is 1 μm to 5 μm. The mass ratio of the silicone rubber to the carbonyl iron powder is 100:200 to 100:

400. The magnetorheological elastomer is cured and formed under a pre-applied magnetic field of 0 mT to 700 mT.

6. The intelligent driving steering safety control system as described in claim 4, characterized in that, The steering execution module also includes: The container has an internal cavity, and the moving part is disposed within the cavity; An excitation coil is disposed around the periphery of the receiving cavity and coupled to the field energy control module; A heating element is disposed inside the moving part and coupled to the field energy control module; A temperature sensing element is disposed on the surface of the moving part and coupled to the field energy control module; Vibration sensing elements and / or strain sensing elements are disposed inside the moving part and coupled to the field energy control module; The tie rod module also includes: An excitation coil sleeve is fitted over the outside of the rod and coupled to the field energy control module; A heating element is disposed inside the rod body and coupled to the field energy control module; Displacement sensing elements are disposed at both ends of the rod and coupled to the field energy control module. The displacement sensing elements are linear displacement sensing elements with a measurement range of 0 mm to 50 mm. A rectifier energy storage unit is disposed at one end of the rod and coupled to the heating element.

7. The intelligent driving steering safety control system as described in claim 4, characterized in that, The field energy regulation module includes: A magnetic field control unit, coupled to the excitation coil, receives a first command output by the mode decision unit and outputs an adjustable current to the excitation coil; A thermal field control unit, coupled to the heating element, receives a second command output by the mode decision unit and outputs an adjustable current to the heating element; The state acquisition unit is coupled to the temperature sensing element, vibration sensing element, strain sensing element and displacement sensing element, and processes the acquired signals and outputs them to the mode decision unit. The mode decision unit, coupled with the magnetic field control unit, thermal field control unit, state acquisition unit, vehicle intelligent driving system, vehicle attitude sensor, and collision prediction sensor, generates decision commands based on the signals output by the state acquisition unit, the driving state output by the vehicle intelligent driving system, the attitude information output by the vehicle attitude sensor, and the prediction information output by the collision prediction sensor. It then outputs the first command to the magnetic field control unit and the second command to the thermal field control unit. The energy storage control unit is coupled to the rectifier energy storage unit, monitors the energy storage status of the rectifier energy storage unit, and outputs an energy storage release signal to the thermal field control unit in the power-off mode.

8. The intelligent driving steering safety control system as described in claim 1, characterized in that, In the emergency obstacle avoidance mode, the field energy control module cuts off or reduces the current of the excitation coil and applies a pulse current with a duration of 50ms to 200ms through the heating element, thereby reducing the elastic modulus of the Ni-Ti alloy matrix by 20% to 40%. In the pre-collision trigger mode, the field energy control module applies a pulse current with a frequency of 5Hz to 20Hz and a duty cycle of 30% to 70% to the heating element, causing the rod to undergo a 5mm to 20mm extension and contraction deformation. In the collision protection mode, the field energy control module burns out the fuse of the excitation coil and releases the energy stored in the energy storage capacitor, causing the magnetorheological elastomer particles to reach a magnetic saturation state. The equivalent damping coefficient of the crossbar module is more than 20 times the conventional value, and the axial displacement of the rod under the restricted state does not exceed ±0.5mm.

9. The intelligent driving steering safety control system as described in claim 1, characterized in that, In the power-off mode, the rectifier energy storage unit rectifies the induced current and stores it in a capacitor. The stored energy is periodically released to the heating element to intermittently heat the rod. The output power of the rectifier energy storage unit is 50mW to 500mW, the starting power of the heating element is 100mW to 1000mW, and the energy stored in the capacitor is 10J to 100J. The straight-line driving position refers to the position where the steering angle of both the left and right front wheels is 0° when the vehicle is driving straight on a level road. It is determined by monitoring the axial displacement of the rod through the displacement sensing element. The tie rod module also has a mechanical energy storage unit, which includes an elastic element and a locking element. When the field energy control module is energized, the elastic element is kept compressed by the locking element. In the power-off mode, the locking element releases the elastic element, and the elastic potential energy of the elastic element pushes the rod to move towards the straight-line driving position.

10. A method for controlling steering safety in intelligent driving according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Collect steering torque and vibration signals through vibration sensing elements and / or strain sensing elements, collect temperature signals through temperature sensing elements, and collect axial displacement signals of the tie rod through displacement sensing elements. S2. The state acquisition unit of the field energy regulation module receives the signal collected in step S1, processes it, and outputs it to the mode decision unit. The mode decision unit determines the safety situation based on the signal, vehicle driving status, and collision prediction information: when the collision prediction sensor outputs a collision time of less than 300ms, it is determined to be a pre-collision situation; when the collision sensor detects that the acceleration exceeds a preset threshold, it is determined to be a collision in progress situation; when the field energy regulation module detects that the main power supply is cut off, it is determined to be a power failure situation; in other cases, it is determined to be a normal situation or an emergency obstacle avoidance situation based on the amplitude of the steering torque signal. S3. The mode decision unit selects the target mode according to the safety situation determined in step S2, and outputs corresponding instructions to the magnetic field control unit and / or thermal field control unit respectively: normal situation corresponds to normal driving mode, emergency obstacle avoidance situation corresponds to emergency obstacle avoidance mode, pre-collision situation corresponds to pre-collision triggering mode, collision in progress situation corresponds to collision protection mode, and power failure situation corresponds to power failure mode.

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